Aerodynamics power consumption for mechanical flapping wings undergoing flapping and pitching motion

NASA Astrophysics Data System (ADS)

Razak, N. A.; Dimitriadis, G.; Razaami, A. F.

2017-07-01

Lately, due to the growing interest in Micro Aerial Vehicles (MAV), interest in flapping flight has been rekindled. The reason lies in the improved performance of flapping wing flight at low Reynolds number regime. Many studies involving flapping wing flight focused on the generation of unsteady aerodynamic forces such as lift and thrust. There is one aspect of flapping wing flight that received less attention. The aspect is aerodynamic power consumption. Since most mechanical flapping wing aircraft ever designed are battery powered, power consumption is fundamental in improving flight endurance. This paper reports the results of experiments carried out on mechanical wings under going active root flapping and pitching in the wind tunnel. The objective of the work is to investigate the effect of the pitch angle oscillations and wing profile on the power consumption of flapping wings via generation of unsteady aerodynamic forces. The experiments were repeated for different airspeeds, flapping and pitching kinematics, geometric angle of attack and wing sections with symmetric and cambered airfoils. A specially designed mechanical flapper modelled on large migrating birds was used. It will be shown that, under pitch leading conditions, less power is required to overcome the unsteady aerodnamics forces. The study finds less power requirement for downstroke compared to upstroke motion. Overall results demonstrate power consumption depends directly on the unsteady lift force.

BCL-2 and Bax Expression in Skin Flaps Treated with Finasteride or Azelaic Acid

PubMed Central

Ayatollahi, Seyyed Abdulmajid; Ajami, Marjan; Reyhanfard, Hamed; Asadi, Yasin; Nassiri-Kashani, Mansour; Rashighi Firoozabadi, Mehdi; Davoodi, Sayed Hossein; Habibi, Esmaeil; Pazoki-Toroudi, Hamidreza

2012-01-01

Despite all modern surgical techniques, skin flap that is considered as the main method in most reconstructive surgeries puts the skin tissue at danger of necrosis and apoptosis derived from ischemia. Therefore, finding a treatment for decreasing the apoptosis derived from flap ischemia will be useful in clinic. In present study, we evaluated the effect of azelaic acid 20% and finasteride on expression of BCL-2 and bax proteins after the skin flap surgery. For this purpose, 21 rats were entered in three groups including control, azelaic acid 20% and finasteride, all experienced skin flap surgery and then flap tissue was assessed for determining the expression of proteins in 5 slices prepared from each rat that were graded between – to +++ scales. Both azelaic acid and finasteride increased the expression of BCL-2 protein (p < 0.05) and decrease the expression of bax protein (p < 0.05). These results suggested an antiapoptotic role for finasteride and azelaic acid in preserving the flap after the ischemia reperfusion insult. PMID:24250563

Passive control of the flow around unsteady aerofoils using a self-activated deployable flap

NASA Astrophysics Data System (ADS)

Rosti, Marco E.; Omidyeganeh, Mohammad; Pinelli, Alfredo

2018-03-01

Self-activated feathers are used by many birds to adapt their wing characteristics to the sudden change of flight incidence angle. In particular, dorsal feathers are believed to pop-up as a consequence of unsteady flow separation and to interact with the flow to palliate the sudden stall breakdown typical of dynamic stall. Inspired by the adaptive character of birds feathers, some authors have envisaged the potential benefits of using of flexible flaps mounted on aerodynamic surfaces to counteract the negative aerodynamic effects associated with dynamic stall. This contribution explores more in depth the physical mechanisms that play a role in the modification of the unsteady flow field generated by a NACA0020 aerofoil equipped with an elastically mounted flap undergoing a specific ramp-up manoeuvre. We discuss the design of flaps that limit the severity of the dynamic stall breakdown by increasing the value of the lift overshoot also smoothing its abrupt decay in time. A detailed analysis on the modification of the turbulent and unsteady vorticity field due to the flap flow interaction during the ramp-up motion is also provided to explain the more benign aerodynamic response obtained when the flap is in use.

Four-flap Breast Reconstruction: Bilateral Stacked DIEP and PAP Flaps

PubMed Central

Mayo, James L.; Allen, Robert J.

2015-01-01

Background: In cases of bilateral breast reconstruction when the deep inferior epigastric perforator (DIEP) free flap alone does not provide sufficient volume for body-specific reconstruction, stacking each DIEP flap with a second free flap will deliver added volume and maintain a purely autologous reconstruction. Stacking the profunda artery perforator (PAP) flap with the DIEP flap offers favorable aesthetics and ideal operative efficiency. We present the indications, technique, and outcomes of our experience with 4-flap breast reconstruction using stacked DIEP/PAP flaps. Methods: The authors performed 4-flap DIEP/PAP breast reconstruction in 20 patients who required bilateral reconstruction without adequate single donor flap volume. The timing of reconstruction, average mastectomy/flap weights, and operative time are reported. Complications reviewed include fat necrosis, dehiscence, hematoma, seroma, mastectomy flap necrosis, and flap loss. Results: Twenty patients underwent 4-flap DIEP/PAP breast reconstruction. Surgical time averaged 7 hours and 20 minutes. The primary recipient vessels were the antegrade and retrograde internal mammary vessels. No flap losses occurred. Complications included 1 hematoma, 1 incidence of arterial and venous thrombosis successfully treated with anastomotic revision, 1 incidence of thigh donor site dehiscence, and 3 episodes of minor mastectomy skin flap necrosis. Conclusions: Four-flap breast reconstruction is a favorable autologous reconstructive option for patients requiring bilateral reconstruction without adequate single donor flap volume. Stacking DIEP/PAP flaps as described is both safe and efficient. Furthermore, this combination provides superior aesthetics mirroring the natural geometry of the breast. Bilateral stacked DIEP/PAP flaps represent our first choice for breast reconstruction in this patient population. PMID:26090273

Control of Flap Vortices

NASA Technical Reports Server (NTRS)

Greenblatt, David

2005-01-01

A wind tunnel investigation was carried out on a semi-span wing model to assess the feasibility of controlling vortices emanating from outboard flaps and tip-flaps by actively varying the degree of boundary layer separation. Separation was varied by means of perturbations produced from segmented zero-efflux oscillatory blowing slots, while estimates of span loadings and vortex sheet strengths were obtained by integrating wing surface pressures. These estimates were used as input to inviscid rollup relations as a means of predicting changes to the vortex characteristics resulting from the perturbations. Surveys of flow in the wake of the outboard and tip-flaps were made using a seven-hole probe, from which the vortex characteristics were directly deduced. Varying the degree of separation had a marked effect on vortex location, strength, tangential velocity, axial velocity and size for both outboard and tip-flaps. Qualitative changes in vortex characteristics were well predicted by the inviscid rollup relations, while the failure to account for viscosity was presumed to be the main reason for observed discrepancies. Introducing perturbations near the outboard flap-edges or on the tip-flap exerted significant control over vortices while producing negligible lift excursions.

Discovery of the first dual inhibitor of the 5-lipoxygenase-activating protein and soluble epoxide hydrolase using pharmacophore-based virtual screening

NASA Astrophysics Data System (ADS)

Temml, Veronika; Garscha, Ulrike; Romp, Erik; Schubert, Gregor; Gerstmeier, Jana; Kutil, Zsofia; Matuszczak, Barbara; Waltenberger, Birgit; Stuppner, Hermann; Werz, Oliver; Schuster, Daniela

2017-02-01

Leukotrienes (LTs) are pro-inflammatory lipid mediators derived from arachidonic acid (AA) with roles in inflammatory and allergic diseases. The biosynthesis of LTs is initiated by transfer of AA via the 5-lipoxygenase-activating protein (FLAP) to 5-lipoxygenase (5-LO). FLAP inhibition abolishes LT formation exerting anti-inflammatory effects. The soluble epoxide hydrolase (sEH) converts AA-derived anti-inflammatory epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatetraenoic acids (di-HETEs). Its inhibition consequently also counteracts inflammation. Targeting both LT biosynthesis and the conversion of EETs with a dual inhibitor of FLAP and sEH may represent a novel, powerful anti-inflammatory strategy. We present a pharmacophore-based virtual screening campaign that led to 20 hit compounds of which 4 targeted FLAP and 4 were sEH inhibitors. Among them, the first dual inhibitor for sEH and FLAP was identified, N-[4-(benzothiazol-2-ylmethoxy)-2-methylphenyl]-N’-(3,4-dichlorophenyl)urea with IC50 values of 200 nM in a cell-based FLAP test system and 20 nM for sEH activity in a cell-free assay.

Medial sural artery perforator flap: a challenging free flap.

PubMed

Toyserkani, Navid Mohamadpour; Sørensen, Jens Ahm

Oral and extremity defect reconstruction can often require a flap that is thin, and traditionally, the radial forearm free flap has been used, however, this has significant donor site morbidity. Over the last decade, the medial sural artery perforator (MSAP) flap has emerged as a possible alternative with lower donor site morbidity. We present our experiences and review the literature regarding this promising but challenging flap. The study was a retrospective case series in a university hospital setting. All patients who had a MSAP flap performed at our institution were included until March 2015, and their data was retrieved from electronic patient records. In total, ten patients were reconstructed with a MSAP flap for floor of mouth (eight) and lower extremity (two) defect reconstruction. The median flap dimensions were as follows: 10 cm (range 7-14 cm), width 5 cm (range 3.5-8 cm), thickness 5 mm (range 4-8 mm), and pedicle length 10 cm (range 8-12 cm). In one case, the procedure was abandoned because of very small perforators and another flap was used. In two cases, late onset of venous congestion occurred which could not be salvaged. There were no donor site complaints. The MSAP flap is an ideal flap when a thin free flap is needed with lower donor site morbidity than alternative solutions. There seems to be a higher rate of late onset of venous thrombosis compared with more established flaps. Therefore, this flap should be monitored more closely for venous problems and we recommend performing two venous anastomoses when using this flap. Level of Evidence: Level IV, therapeutic study.

Free-style puzzle flap: the concept of recycling a perforator flap.

PubMed

Feng, Kuan-Ming; Hsieh, Ching-Hua; Jeng, Seng-Feng

2013-02-01

Theoretically, a flap can be supplied by any perforator based on the angiosome theory. In this study, the technique of free-style perforator flap dissection was used to harvest a pedicled or free skin flap from a previous free flap for a second difficult reconstruction. The authors call this a free-style puzzle flap. For the past 3 years, the authors treated 13 patients in whom 12 pedicled free-style puzzle flaps were harvested from previous redundant free flaps and recycled to reconstruct soft-tissue defects at various anatomical locations. One free-style free puzzle flap was harvested from a previous anterolateral thigh flap for buccal cancer to reconstruct a foot defect. Total flap survival was attained in 12 of 13 flaps. One transferred flap failed completely. This patient had received postoperative radiotherapy after the initial cancer ablation and free anterolateral thigh flap reconstruction. Another free flap was used to close and reconstruct the wound. All the donor sites could be closed primarily. The free-style puzzle flap, harvested from a previous redundant free flap and used as a perforator flap to reconstruct a new defect, has proven to be versatile and reliable. When indicated, it is an alternative donor site for further reconstruction of soft-tissue defects.

Translational damping on high-frequency flapping wings

NASA Astrophysics Data System (ADS)

Parks, Perry A.

Flapping fliers such as insects and birds depend on passive translational and rotational damping to terminate quick maneuvers and to provide a source of partial stability in an otherwise unstable dynamic system. Additionally, passive translational and rotational damping reduce the amount of active kinematic changes that must be made to terminate maneuvers and maintain stability. The study of flapping-induced damping phenomena also improves the understanding of micro air vehicle (MAV) dynamics needed for the synthesis of effective flight control strategies. Aerodynamic processes which create passive translational and rotational damping as a direct result of symmetric flapping with no active changes in wing kinematics have been previously studied and were termed flapping counter-force (FCF) and flapping counter-torque (FCT), respectively. In this first study of FCF measurement in air, FCF generation is measured using a pendulum system designed to isolate and measure the relationship of translational flapping-induced damping with wingbeat frequency for a 2.86 gram mechanical flapper equipped with real cicada wings. Analysis reveals that FCF generation and wingbeat frequency are directly proportional, as expected from previous work. The quasi-steady FCF model using Blade-Element-Theory is used as an estimate for translational flapping-induced damping. In most cases, the model proves to be accurate in predicting the relationship between flapping-induced damping and wingbeat frequency. "Forward-backward" motion proves to have the strongest flapping-induced damping while "up-down" motion has the weakest.

Tanshinone IIA Pretreatment Renders Free Flaps against Hypoxic Injury through Activating Wnt Signaling and Upregulating Stem Cell-Related Biomarkers

PubMed Central

Xu, Zihan; Zhang, Zhenxin; Wu, Lijun; Sun, Yaowen; Guo, Yadong; Qin, Gaoping; Mu, Shengzhi; Fan, Ronghui; Wang, Benfeng; Gao, Wenjie

2014-01-01

Partial or total flap necrosis after flap transplantation is sometimes clinically encountered in reconstructive surgery, often as a result of a period of hypoxia that exceeds the tolerance of the flap tissue. In this study, we determine whether tanshinone IIA (TSA) pretreatment can protect flap tissue against hypoxic injury and improve its viability. Primary epithelial cells isolated from the dorsal skin of mice were pretreated with TSA for two weeks. Cell counting kit-8 and Trypan Blue assays were carried out to examine the proliferation of TSA-pretreated cells after exposure to cobalt chloride. Then, Polymerase chain reaction and Western blot analysis were used to determine the expression of β-catenin, GSK-3β, SOX2, and OCT4 in TSA-treated cells. In vivo, after mice were pretreated with TSA for two weeks, a reproducible ischemic flap model was implemented, and the area of surviving tissue in the transplanted flaps was measured. Immunohistochemistry was also conducted to examine the related biomarkers mentioned above. Results show that epidermal cells, pretreated with TSA, showed enhanced resistance to hypoxia. Activation of the Wnt signaling pathway in TSA-pretreated cells was characterized by the upregulation of β-catenin and the downregulation of GSK-3β. The expression of SOX2 and OCT4 controlled by Wnt signaling were also found higher in TSA pretreated epithelial cells. In the reproducible ischaemic flap model, pretreatment with TSA enhanced resistance to hypoxia and increased the area of surviving tissue in transplanted flaps. The expression of Wnt signaling pathway components, stem-cell related biomarkers, and CD34, which are involved in the regeneration of blood vessels, was also upregulated in TSA-pretreated flap tissue. The results show that TSA pretreatment protects free flaps against hypoxic injury and increases the area of surviving tissue by activating Wnt signaling and upregulating stem cell-related biomarkers. PMID:25302618

Naringin improves random skin flap survival in rats.

PubMed

Cheng, Liang; Chen, Tingxiang; Tu, Qiming; Li, Hang; Feng, Zhenghua; Li, Zhijie; Lin, Dingsheng

2017-11-07

Random-pattern flap transfer is commonly used to treat soft-tissue defects. However, flap necrosis remains a serious problem. Naringin accelerates angiogenesis by activating the expression of vascular endothelial growth factor (VEGF). In the present study, we investigated whether naringin improves the survival of random skin flaps. Compared with controls, the naringin-treated groups exhibited significantly larger mean areas of flap survival, significantly increased SOD activity and VEGF expression, and significantly reduced MDA level. Hematoxylin and eosin (HE) staining revealed that naringin promoted angiogenesis and inhibited inflammation. "McFarlane flap" models were established in 90 male Sprague-Dawley (SD) rats divided into three groups: a 40 mg/kg control group (0.5 % sodium carboxymethylcellulose), a 40 mg/kg naringin-treated group, and an 80 mg/kg naringin-treated group. The extent of necrosis was measured 7 days later, and tissue samples were subjected to histological analysis. Angiogenesis was evaluated via lead oxide-gelatin angiography, immunohistochemistry, and laser Doppler imaging. Inflammation was evaluated by measurement of serum TNF-α (tumor necrosis factor-α) and IL-6 (interleukin-6) levels. Oxidative stress was assessed by measuring superoxide dismutase (SOD) activity and the malondialdehyde (MDA) level. Naringin improved random skin flap survival.

Rate-determining Step of Flap Endonuclease 1 (FEN1) Reflects a Kinetic Bias against Long Flaps and Trinucleotide Repeat Sequences.

PubMed

Tarantino, Mary E; Bilotti, Katharina; Huang, Ji; Delaney, Sarah

2015-08-21

Flap endonuclease 1 (FEN1) is a structure-specific nuclease responsible for removing 5'-flaps formed during Okazaki fragment maturation and long patch base excision repair. In this work, we use rapid quench flow techniques to examine the rates of 5'-flap removal on DNA substrates of varying length and sequence. Of particular interest are flaps containing trinucleotide repeats (TNR), which have been proposed to affect FEN1 activity and cause genetic instability. We report that FEN1 processes substrates containing flaps of 30 nucleotides or fewer at comparable single-turnover rates. However, for flaps longer than 30 nucleotides, FEN1 kinetically discriminates substrates based on flap length and flap sequence. In particular, FEN1 removes flaps containing TNR sequences at a rate slower than mixed sequence flaps of the same length. Furthermore, multiple-turnover kinetic analysis reveals that the rate-determining step of FEN1 switches as a function of flap length from product release to chemistry (or a step prior to chemistry). These results provide a kinetic perspective on the role of FEN1 in DNA replication and repair and contribute to our understanding of FEN1 in mediating genetic instability of TNR sequences. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Topical application of nitrosonifedipine, a novel radical scavenger, ameliorates ischemic skin flap necrosis in a mouse model.

PubMed

Fukunaga, Yutaka; Izawa-Ishizawa, Yuki; Horinouchi, Yuya; Sairyo, Eriko; Ikeda, Yasumasa; Ishizawa, Keisuke; Tsuchiya, Koichiro; Abe, Yoshiro; Hashimoto, Ichiro; Tamaki, Toshiaki

2017-04-01

Ischemic skin flap necrosis can occur in random pattern flaps. An excess amount of reactive oxygen species is generated and causes necrosis in the ischemic tissue. Nitrosonifedipine (NO-NIF) has been demonstrated to possess potent radical scavenging ability. However, there has been no study on the effects of NO-NIF on ischemic skin flap necrosis. Therefore, they evaluated the potential of NO-NIF in ameliorating ischemic skin flap necrosis in a mouse model. A random pattern skin flap (1.0 × 3.0 cm) was elevated on the dorsum of C57BL/6 mice. NO-NIF was administered by topical injection immediately after surgery and every 24 hours thereafter. Flap survival was evaluated on postoperative day 7. Tissue samples from the skin flaps were harvested on postoperative days 1 and 3 to analyze oxidative stress, apoptosis and endothelial dysfunction. The viable area of the flap in the NO-NIF group was significantly increased (78.30 ± 7.041%) compared with that of the control group (47.77 ± 6.549%, p < 0.01). NO-NIF reduced oxidative stress, apoptosis and endothelial dysfunction, which were evidenced by the decrease of malondialdehyde, p22phox protein expression, number of apoptotic cells, phosphorylated p38 MAPK protein expression, and vascular cell adhesion molecule-1 protein expression while endothelial nitric oxide synthase protein expression was increased. In conclusion, they demonstrated that NO-NIF ameliorated ischemic skin flap necrosis by reducing oxidative stress, apoptosis, and endothelial dysfunction. NO-NIF is considered to be a candidate for the treatment of ischemic flap necrosis. © 2017 by the Wound Healing Society.

Extreme load alleviation using industrial implementation of active trailing edge flaps in a full design load basis

NASA Astrophysics Data System (ADS)

Barlas, Thanasis; Pettas, Vasilis; Gertz, Drew; Madsen, Helge A.

2016-09-01

The application of active trailing edge flaps in an industrial oriented implementation is evaluated in terms of capability of alleviating design extreme loads. A flap system with basic control functionality is implemented and tested in a realistic full Design Load Basis (DLB) for the DTU 10MW Reference Wind Turbine (RWT) model and for an upscaled rotor version in DTU's aeroelastic code HAWC2. The flap system implementation shows considerable potential in reducing extreme loads in components of interest including the blades, main bearing and tower top, with no influence on fatigue loads and power performance. In addition, an individual flap controller for fatigue load reduction in above rated power conditions is also implemented and integrated in the general controller architecture. The system is shown to be a technology enabler for rotor upscaling, by combining extreme and fatigue load reduction.

Effect of pre-slaughter shackling and wing flapping on plasma parameters, postmortem metabolism, AMPK, and meat quality of broilers.

PubMed

Huang, J C; Yang, J; Huang, M; Zhu, Z S; Sun, X B; Zhang, B H; Xu, X L; Meng, W G; Chen, K J; Xu, B C

2018-05-01

The objective of this study was to determine the effects of shackling and wing flapping on stress, postmortem metabolism, AMP-activated protein kinase (AMPK), and quality of broiler pectoralis major. Before slaughter, a total of 80 Arbor Acres broilers was randomly categorized into 2 replicate pens (40 broilers per pen) and each pen randomly divided into 2 groups (shackling, T; control, C). Corticosterone, creatine kinase, and lactate dehydrogenase were determined on blood plasma parameters. Pectoralis major were removed after evisceration and used for determination of energy metabolism, meat quality, and AMPK phosphorylation. In this study, shackling and wing flapping increased (P < 0.05) plasma corticosterone level, creatine kinase activity, and lactate dehydrogenase activity. Shackling and wing flapping increased (P < 0.05) AMPKα(Thr172) and acetyl-CoA carboxylase (ACC) phosphorylation, followed by rapid glycolysis and accumulation of lactic acid, and leading to a fast pH decline in the initial postmortem meat. Shackling and wing flapping have an adverse effect on final meat quality, which increased (P < 0.05) muscle lightness, drip loss, and cooking loss. The results indicate that antemortem shackling and wing flapping increased stress and AMPKα(Thr172) phosphorylation, which may accelerate glycolysis and lead to a low water-holding capacity of broiler meat.

Pharmacological profile and efficiency in vivo of diflapolin, the first dual inhibitor of 5-lipoxygenase-activating protein and soluble epoxide hydrolase.

PubMed

Garscha, Ulrike; Romp, Erik; Pace, Simona; Rossi, Antonietta; Temml, Veronika; Schuster, Daniela; König, Stefanie; Gerstmeier, Jana; Liening, Stefanie; Werner, Markus; Atze, Heiner; Wittmann, Sandra; Weinigel, Christina; Rummler, Silke; Scriba, Gerhard K; Sautebin, Lidia; Werz, Oliver

2017-08-24

Arachidonic acid (AA) is metabolized to diverse bioactive lipid mediators. Whereas the 5-lipoxygenase-activating protein (FLAP) facilitates AA conversion by 5-lipoxygenase (5-LOX) to pro-inflammatory leukotrienes (LTs), the soluble epoxide hydrolase (sEH) degrades anti-inflammatory epoxyeicosatrienoic acids (EETs). Accordingly, dual FLAP/sEH inhibition might be advantageous drugs for intervention of inflammation. We present the in vivo pharmacological profile and efficiency of N-[4-(benzothiazol-2-ylmethoxy)-2-methylphenyl]-N'-(3,4-dichlorophenyl)urea (diflapolin) that dually targets FLAP and sEH. Diflapolin inhibited 5-LOX product formation in intact human monocytes and neutrophils with IC 50  = 30 and 170 nM, respectively, and suppressed the activity of isolated sEH (IC 50  = 20 nM). Characteristic for FLAP inhibitors, diflapolin (I) failed to inhibit isolated 5-LOX, (II) blocked 5-LOX product formation in HEK cells only when 5-LOX/FLAP was co-expressed, (III) lost potency in intact cells when exogenous AA was supplied, and (IV) prevented 5-LOX/FLAP complex assembly in leukocytes. Diflapolin showed target specificity, as other enzymes related to AA metabolism (i.e., COX1/2, 12/15-LOX, LTA 4 H, LTC 4 S, mPGES 1 , and cPLA 2 ) were not inhibited. In the zymosan-induced mouse peritonitis model, diflapolin impaired vascular permeability, inhibited cysteinyl-LTs and LTB 4 formation, and suppressed neutrophil infiltration. Diflapolin is a highly active dual FLAP/sEH inhibitor in vitro and in vivo with target specificity to treat inflammation-related diseases.

Water Tunnel Studies of Dynamic Wing Flap Effects

DTIC Science & Technology

2016-06-01

applications where dynamic flaps have been studied are in the active elevon rotor and wind turbines . Any analytical or computational study needs to be...observed here that most of these pertain to other applications such as rotorcraft and wind turbine flow control. At times, a Gurney flap has been for...the flap-slices used. Source: [12]. .......................14 Figure 6. NACA 2212 at wind tunnel section. Source: [8

The temporalis muscle flap and temporoparietal fascial flap.

PubMed

Lam, Din; Carlson, Eric R

2014-08-01

The temporal arterial system provides reliable vascular anatomy for the temporalis muscle flap and temporoparietal fascial flap that can support multiple reconstructive needs of the oral and maxillofacial region. The minimal donor site morbidity and ease of development of these flaps result in their predictable and successful transfer for reconstructive surgery of the oral and maxillofacial region. Copyright © 2014 Elsevier Inc. All rights reserved.

Phosphate steering by Flap Endonuclease 1 promotes 5'-flap specificity and incision to prevent genome instability

DOE PAGES

Tsutakawa, Susan E.; Thompson, Mark J.; Arvai, Andrew S.; ...

2017-06-27

DNA replication and repair enzyme Flap Endonuclease 1 (FEN1) is vital for genome integrity, and FEN1 mutations arise in multiple cancers. FEN1 precisely cleaves single-stranded (ss) 5'-flaps one nucleotide into duplex (ds) DNA. Yet, how FEN1 selects for but does not incise the ss 5'-flap was enigmatic. Here we combine crystallographic, biochemical and genetic analyses to show that two dsDNA binding sites set the 5'polarity and to reveal unexpected control of the DNA phosphodiester backbone by electrostatic interactions. Via phosphate steering', basic residues energetically steer an inverted ss 5'-flap through a gateway over FEN1's active site and shift dsDNA formore » catalysis. Mutations of these residues cause an 18,000-fold reduction in catalytic rate in vitro and large-scale trinucleotide (GAA) n repeat expansions in vivo, implying failed phosphate-steering promotes an unanticipated lagging-strand template-switch mechanism during replication. Thus, phosphate steering is an unappreciated FEN1 function that enforces 5'-flap specificity and catalysis, preventing genomic instability.« less

Phosphate steering by Flap Endonuclease 1 promotes 5'-flap specificity and incision to prevent genome instability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsutakawa, Susan E.; Thompson, Mark J.; Arvai, Andrew S.

DNA replication and repair enzyme Flap Endonuclease 1 (FEN1) is vital for genome integrity, and FEN1 mutations arise in multiple cancers. FEN1 precisely cleaves single-stranded (ss) 5'-flaps one nucleotide into duplex (ds) DNA. Yet, how FEN1 selects for but does not incise the ss 5'-flap was enigmatic. Here we combine crystallographic, biochemical and genetic analyses to show that two dsDNA binding sites set the 5'polarity and to reveal unexpected control of the DNA phosphodiester backbone by electrostatic interactions. Via phosphate steering', basic residues energetically steer an inverted ss 5'-flap through a gateway over FEN1's active site and shift dsDNA formore » catalysis. Mutations of these residues cause an 18,000-fold reduction in catalytic rate in vitro and large-scale trinucleotide (GAA) n repeat expansions in vivo, implying failed phosphate-steering promotes an unanticipated lagging-strand template-switch mechanism during replication. Thus, phosphate steering is an unappreciated FEN1 function that enforces 5'-flap specificity and catalysis, preventing genomic instability.« less

Instep island flaps.

PubMed

Reading, G

1984-12-01

The instep island flap is safe and useful. It is based on branches of the posterior tibial artery and can be a musculocutaneous or a direct fasciocutaneous island flap. Sensory branches of the digital nerves may be transposed with the flap. There is a wide arc of transposition and the flap has survived even in very difficult circumstances.

Mutational analysis of the active site flap (20s loop) of mandelate racemase.

PubMed

Bourque, Jennifer R; Bearne, Stephen L

2008-01-15

Mandelate racemase from Pseudomonas putida catalyzes the Mg2+-dependent 1,1-proton transfer that interconverts the enantiomers of mandelate. Residues of the 20s and 50s loops determine, in part, the topology and polarity of the active site and hence the substrate specificity. Previously, we proposed that, during racemization, the phenyl ring of mandelate moves between an S-pocket comprised of residues from the 50s loop and an R-pocket comprised of residues from the 20s loop [Siddiqi, F., Bourque, J. R., Jiang, H., Gardner, M., St. Maurice, M., Blouin, C., and Bearne, S. L. (2005) Biochemistry 44, 9013-9021]. The 20s loop constitutes a mobile beta-meander flap that covers the active site cavity shielding it from solvent and controlling entry and egress of ligands. To understand the role of the 20s loop in catalysis and substrate specificity, we constructed a series of mutants (V22A, V22I, V22F, T24S, A25V, V26A, V26L, V26F, V29A, V29L, V29F, V26A/V29L, and V22I/V29L) in which the sizes of hydrophobic side chains of the loop residues were varied. Catalytic efficiencies (kcat/Km) for all mutants were reduced between 6- and 40-fold with the exception of those of V22I, V26A, V29L, and V22I/V29L which had near wild-type efficiencies with mandelate. Thr 24 and Ala 25, located at the tip of the 20s loop, were particularly sensitive to minor alterations in the size of their hydrophobic side chains; however, most mutations were tolerated quite well, suggesting that flap mobility could compensate for increases in the steric bulk of hydrophobic side chains. With the exception of V29L, with mandelate as the substrate, and V22F and V26A/V29L, with 2-naphthylglycolate (2-NG) as the substrate, the values of kcat and Km were not altered in a manner consistent with steric obstruction of the R-pocket, perhaps due to flap mobility compensating for the increased size of the hydrophobic side chains. Surprisingly, V22I and V29L catalyzed the racemization of the bulkier substrate 2-NG

4-Phenylbutyrate protects rat skin flaps against ischemia-reperfusion injury and apoptosis by inhibiting endoplasmic reticulum stress

PubMed Central

YUE, ZHEN-SHUANG; ZENG, LIN-RU; QUAN, REN-FU; TANG, YANG-HUA; ZHENG, WEN-JIE; QU, GANG; XU, CAN-DA; ZHU, FANG-BING; HUANG, ZHONG-MING

2016-01-01

4-phenylbutyrate (4-PBA) is a low molecular weight fatty acid, which has been demonstrated to regulate endoplasmic reticulum (ER) stress. ER stress-induced cell apoptosis has an important role in skin flap ischemia; however, a pharmacological approach for treating ischemia-induced ER dysfunction has yet to be reported. In the present study, the effects of 4-PBA-induced ER stress inhibition on ischemia-reperfusion injury were investigated in the skin flap of rats, and transcriptional regulation was examined. 4-PBA attenuated ischemia-reperfusion injury and inhibited cell apoptosis in the skin flap. Furthermore, 4-PBA reversed the increased expression levels of two ER stress markers: CCAAT/enhancer-binding protein-homologous protein and glucose-regulated protein 78. These results suggested that 4-PBA was able to protect rat skin flaps against ischemia-reperfusion injury and apoptosis by inhibiting ER stress marker expression and ER stress-mediated apoptosis. The beneficial effects of 4-PBA may prove useful in the treatment of skin flap ischemia-reperfusion injury. PMID:26648447

Reduction of Flap Side Edge Noise - the Blowing Flap

NASA Technical Reports Server (NTRS)

Hutcheson, Florence V.; Brooks, THomas F.

2005-01-01

A technique to reduce the noise radiating from a wing-flap side edge is being developed. As an airplane wing with an extended flap is exposed to a subsonic airflow, air is blown outward through thin rectangular chord-wise slots at various locations along the side edges and side surface of the flap to weaken and push away the vortices that originate in that region of the flap and are responsible for important noise emissions. Air is blown through the slots at up to twice the local flow velocity. The blowing is done using one or multiple slots, where a slot is located along the top, bottom or side surface of the flap along the side edge, or also along the intersection of the bottom (or top) and side surfaces.

Lower-limb reconstruction with chimeric flaps: The quad flap.

PubMed

Azouz, Solomon M; Castel, Nikki A; Vijayasekaran, Aparna; Rebecca, Alanna M; Lettieri, Salvatore C

2018-05-07

Early soft-tissue coverage is critical for treating traumatic open lower-extremity wounds. As free-flap reconstruction evolves, injuries once thought to be nonreconstructable are being salvaged. Free-tissue transfer is imperative when there is extensive dead space or exposure of vital structures such as bone, tendon, nerves, or blood vessels. We describe 2 cases of lower-extremity crush injuries salvaged with the quad flap. This novel flap consists of parascapular, scapular, serratus, and latissimus dorsi free flaps in combination on one pedicle. This flap provides the large amount of soft-tissue coverage necessary to cover substantial defects from skin degloving, tibia and fibula fractures, and soft-tissue loss. In case 1, a 51-year-old woman was struck by an automobile and sustained bilateral tibia and fibula fractures, a crush degloving injury of the left leg, and a right forefoot traumatic amputation. She underwent reconstruction with a contralateral quad free flap. In case 2, a 53-year-old man sustained a right tibia plateau fracture with large soft-tissue defects from a motorcycle accident. He had a crush degloving injury of the entire anterolateral compartment over the distal and lower third of the right leg. The large soft-tissue defect was reconstructed with a contralateral quad flap. In both cases, the donor site was closed primarily and without early flap failures. There was one surgical complication, an abscess in case 2; the patient was taken back to the operating room for débridement of necrotic tissue. There have been no long-term complications in either case. Both patients achieved adequate soft-tissue coverage, avoided amputation, and had satisfactory aesthetic and functional outcomes. With appropriate surgical technique and patient selection, the quad-flap technique is promising for reconstructing the lower extremity. © 2018 Wiley Periodicals, Inc.

Free-style free flaps.

PubMed

Wei, Fu-Chan; Mardini, Samir

2004-09-15

Free-tissue transfer has become the accepted standard for reconstruction of complex defects. With the growth of this field, anatomic studies and clinical work have added many flaps to the armamentarium of the microvascular surgeon. Further advancements and experience with techniques of perforator flap surgery have allowed for the harvest of flaps in a free-style manner, where a flap is harvested based only on the preoperative knowledge of Doppler signals present in a specific region. Between June of 2002 and September of 2003, 13 free-style free flaps were harvested from the region of the thigh. All patients presented with an oral or pharyngeal cancer and underwent resection and immediate reconstruction of these flaps. All flaps were cutaneous and were harvested in a suprafascial plane. The average size of the flaps was 108 cm2 (range, 36 to 187 cm2), and the average length of the vascular pedicle was 10 cm (range, 9 to 12 cm). All flaps were successful in achieving wound coverage and functional outcomes without any vascular compromise necessitating re-exploration. Free-style free flaps have become a clinical reality. The concepts and techniques used to harvest a free-style free flap will aid in dealing with anatomic variations that are encountered during conventional flap harvest. Future trends in flap selection will focus mainly on choosing tissue with appropriate texture, thickness, and pliability to match requirements at the recipient site while minimizing donor-site morbidity.

Crystal structures of the structure-selective nuclease Mus81-Eme1 bound to flap DNA substrates

PubMed Central

Gwon, Gwang Hyeon; Jo, Aera; Baek, Kyuwon; Jin, Kyeong Sik; Fu, Yaoyao; Lee, Jong-Bong; Kim, YoungChang; Cho, Yunje

2014-01-01

The Mus81-Eme1 complex is a structure-selective endonuclease with a critical role in the resolution of recombination intermediates during DNA repair after interstrand cross-links, replication fork collapse, or double-strand breaks. To explain the molecular basis of 3′ flap substrate recognition and cleavage mechanism by Mus81-Eme1, we determined crystal structures of human Mus81-Eme1 bound to various flap DNA substrates. Mus81-Eme1 undergoes gross substrate-induced conformational changes that reveal two key features: (i) a hydrophobic wedge of Mus81 that separates pre- and post-nick duplex DNA and (ii) a “5′ end binding pocket” that hosts the 5′ nicked end of post-nick DNA. These features are crucial for comprehensive protein-DNA interaction, sharp bending of the 3′ flap DNA substrate, and incision strand placement at the active site. While Mus81-Eme1 unexpectedly shares several common features with members of the 5′ flap nuclease family, the combined structural, biochemical, and biophysical analyses explain why Mus81-Eme1 preferentially cleaves 3′ flap DNA substrates with 5′ nicked ends. PMID:24733841

Naringin improves random skin flap survival in rats

PubMed Central

Cheng, Liang; Chen, Tingxiang; Tu, Qiming; Li, Hang; Feng, Zhenghua; Li, Zhijie; Lin, Dingsheng

2017-01-01

Background Random-pattern flap transfer is commonly used to treat soft-tissue defects. However, flap necrosis remains a serious problem. Naringin accelerates angiogenesis by activating the expression of vascular endothelial growth factor (VEGF). In the present study, we investigated whether naringin improves the survival of random skin flaps. Results Compared with controls, the naringin-treated groups exhibited significantly larger mean areas of flap survival, significantly increased SOD activity and VEGF expression, and significantly reduced MDA level. Hematoxylin and eosin (HE) staining revealed that naringin promoted angiogenesis and inhibited inflammation. Materials and Methods “McFarlane flap” models were established in 90 male Sprague-Dawley (SD) rats divided into three groups: a 40 mg/kg control group (0.5 % sodium carboxymethylcellulose), a 40 mg/kg naringin-treated group, and an 80 mg/kg naringin-treated group. The extent of necrosis was measured 7 days later, and tissue samples were subjected to histological analysis. Angiogenesis was evaluated via lead oxide–gelatin angiography, immunohistochemistry, and laser Doppler imaging. Inflammation was evaluated by measurement of serum TNF-α (tumor necrosis factor-α) and IL-6 (interleukin-6) levels. Oxidative stress was assessed by measuring superoxide dismutase (SOD) activity and the malondialdehyde (MDA) level. Conclusion Naringin improved random skin flap survival. PMID:29212216

Parametric study of fluid flow manipulation with piezoelectric macrofiber composite flaps

NASA Astrophysics Data System (ADS)

Sadeghi, O.; Tarazaga, P.; Stremler, M.; Shahab, S.

2017-04-01

Active Fluid Flow Control (AFFC) has received great research attention due to its significant potential in engineering applications. It is known that drag reduction, turbulence management, flow separation delay and noise suppression through active control can result in significantly increased efficiency of future commercial transport vehicles and gas turbine engines. In microfluidics systems, AFFC has mainly been used to manipulate fluid passing through the microfluidic device. We put forward a conceptual approach for fluid flow manipulation by coupling multiple vibrating structures through flow interactions in an otherwise quiescent fluid. Previous investigations of piezoelectric flaps interacting with a fluid have focused on a single flap. In this work, arrays of closely-spaced, free-standing piezoelectric flaps are attached perpendicular to the bottom surface of a tank. The coupling of vibrating flaps due to their interacting with the surrounding fluid is investigated in air (for calibration) and under water. Actuated flaps are driven with a harmonic input voltage, which results in bending vibration of the flaps that can work with or against the flow-induced bending. The size and spatial distribution of the attached flaps, and the phase and frequency of the input actuation voltage are the key parameters to be investigated in this work. Our analysis will characterize the electrohydroelastic dynamics of active, interacting flaps and the fluid motion induced by the system.

An innovative method of planning and displaying flap volume in DIEP flap breast reconstructions.

PubMed

Hummelink, S; Verhulst, Arico C; Maal, Thomas J J; Hoogeveen, Yvonne L; Schultze Kool, Leo J; Ulrich, Dietmar J O

2017-07-01

Determining the ideal volume of the harvested flap to achieve symmetry in deep inferior epigastric artery perforator (DIEP) flap breast reconstructions is complex. With preoperative imaging techniques such as 3D stereophotogrammetry and computed tomography angiography (CTA) available nowadays, we can combine information to preoperatively plan the optimal flap volume to be harvested. In this proof-of-concept, we investigated whether projection of a virtual flap planning onto the patient's abdomen using a projection method could result in harvesting the correct flap volume. In six patients (n = 9 breasts), 3D stereophotogrammetry and CTA data were combined from which a virtual flap planning was created comprising perforator locations, blood vessel trajectory and flap size. All projected perforators were verified with Doppler ultrasound. Intraoperative flap measurements were collected to validate the determined flap delineation volume. The measured breast volume using 3D stereophotogrammetry was 578 ± 127 cc; on CTA images, 527 ± 106 cc flap volumes were planned. The nine harvested flaps weighed 533 ± 109 g resulting in a planned versus harvested flap mean difference of 5 ± 27 g (flap density 1.0 g/ml). In 41 out of 42 projected perforator locations, a Doppler signal was audible. This proof-of-concept shows in small numbers that flap volumes can be included into a virtual DIEP flap planning, and transferring the virtual planning to the patient through a projection method results in harvesting approximately the same volume during surgery. In our opinion, this innovative approach is the first step in consequently achieving symmetric breast volumes in DIEP flap breast reconstructions. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Experimental Study of Wake / Flap Interaction Noise and the Reduction of Flap Side Edge Noise

NASA Technical Reports Server (NTRS)

Hutcheson, Florence V.; Stead, Daniel J.; Plassman, Gerald E.

2016-01-01

The effects of the interaction of a wake with a half-span flap on radiated noise are examined. The incident wake is generated by bars of various widths and lengths or by a simplified landing gear model. Single microphone and phased array measurements are used to isolate the effects of the wake interaction on the noise radiating from the flap side edge and flap cove regions. The effects on noise of the wake generator's geometry and relative placement with respect to the flap are assessed. Placement of the wake generators upstream of the flap side edge is shown to lead to the reduction of flap side edge noise by introducing a velocity deficit and likely altering the instabilities in the flap side edge vortex system. Significant reduction in flap side edge noise is achieved with a bar positioned directly upstream of the flap side edge. The noise reduction benefit is seen to improve with increased bar width, length and proximity to the flap edge. Positioning of the landing gear model upstream of the flap side edge also leads to decreased flap side edge noise. In addition, flap cove noise levels are significantly lower than when the landing gear is positioned upstream of the flap mid-span. The impact of the local flow velocity on the noise radiating directly from the landing gear is discussed. The effects of the landing gear side-braces on flap side edge, flap cove and landing gear noise are shown.

The midline central artery forehead flap: a valid alternative to supratrochlear-based forehead flaps.

PubMed

Faris, Callum; van der Eerden, Paul; Vuyk, Hade

2015-01-01

This study clarifies the pedicle geometry and vascular supply of a midline forehead flap for nasal reconstruction. It reports on the vascular reliability of this flap and its ability to reduce hair transposition to the nose, a major complicating factor of previous forehead flap designs. To compare the vascular reliability of 3 different pedicle designs of the forehead flap in nasal reconstruction (classic paramedian, glabellar paramedian, and central artery flap design) and evaluate hair transposition rates and aesthetic results. Retrospective analysis of patient data and outcomes retrieved from computer files generated at the time of surgery, supplemented by data from the patient medical records and photographic documentation, from a tertiary referral nasal reconstructive practice, within a secondary-care hospital setting. The study population included all consecutive patients over a 19-year period who underwent primary forehead flap repair of nasal defects, with more than 3 months of postoperative follow-up and photographic documentation. Three sequential forehead flap patterns were used (classic paramedian flap, glabella flap, and central artery flap) for nasal reconstruction over the study duration. Data collected included patient characteristics, method of repair, complications, functional outcome, and patient satisfaction score. For cosmetic outcome, photographic documentation was scored by a medical juror. No forehead flap had vascular compromise in the first stage. Partial flap necrosis was reported in subsequent stages in 4 patients (1%), with no statistical difference in the rate of vascular compromise between the 3 flap designs. Hair transposition to the nose was lower in the central artery forehead flap (7%) compared with the classic paramedian (23%) and glabellar paramedian (13%) flaps (P < .05). Photographic evaluation in 227 patients showed that brow position (98%) and color match (83%) were good in the majority of the patients. In this series

Reconstruction of Complex Facial Defects Using Cervical Expanded Flap Prefabricated by Temporoparietal Fascia Flap.

PubMed

Zhang, Ling; Yang, Qinghua; Jiang, Haiyue; Liu, Ge; Huang, Wanlu; Dong, Weiwei

2015-09-01

Reconstruction of complex facial defects using cervical expanded flap prefabricated by temporoparietal fascia flap. Complex facial defects are required to restore not only function but also aesthetic appearance, so it is vital challenge for plastic surgeons. Skin grafts and traditional flap transfer cannot meet the reconstructive requirements of color and texture with recipient. The purpose of this sturdy is to create an expanded prefabricated temporoparietal fascia flap to repair complex facial defects. Two patients suffered severe burns on the face underwent complex facial resurfacing with prefabricated cervical flap. The vasculature of prefabricated flap, including the superficial temporal vessel and surrounding fascia, was used as the vascular carrier. The temporoparietal fascia flap was sutured underneath the cervical subcutaneous tissue, and expansion was begun in postoperative 1 week. After 4 to 6 months of expansion, the expander was removed, facial scars were excised, and cervical prefabricated flap was elevated and transferred to repair the complex facial defects. Two complex facial defects were repaired successfully by prefabricated temporoparietal fascia flap, and prefabricated flaps survived completely. On account of donor site's skin was thinner and expanded too fast, 1 expanded skin flap was rupture during expansion, but necrosis was not occurred after the 2nd operation. Venous congestion was observed in 1 patient, but after dressing, flap necrosis was not happened. Donor site was closed primarily. Postoperative follow-up 6 months, the color, texture of prefabricated flap was well-matched with facial skin. This method of expanded prefabricated flap may provide a reliable solution to the complex facial resurfacing.

Refining the cross-finger flap: Considerations of flap insetting, aesthetics and donor site morbidity.

PubMed

Chong, Chew-Wei; Lin, Cheng-Hung; Lin, Yu-Te; Hsu, Chung-Chen; Chen, Shih-Heng

2018-04-01

We described a laterally based cross-finger flap for reconstruction of soft tissue defects in the fingers. This modification enables coverage of volar or dorsal soft tissue defects at the distal, middle or proximal phalanx. From March 2015 to January 2017, a total of 12 patients (13 fingers) underwent soft tissue reconstruction of the fingers with a laterally based cross-finger flap. The flap dimensions ranged from 13 ×7 mm to 43 ×13 mm. Eleven of the 13 flaps survived completely. The two flap failures were attributed to injuries in the donor fingers, rendering the blood supply of the flaps unreliable. All donor sites were closed primarily without the need for skin grafting, negating the problem of donor site morbidity that is associated with skin graft harvesting. The laterally based cross-finger flap is a versatile flap with less donor site morbidity and better aesthetics than a conventional cross-finger flap. We described the design of the flap, as well as the advantages and disadvantages, in doing a laterally based cross-finger flap. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Latissimus Dorsi Myocutaneous Flap for Breast Reconstruction: Bad Rap or Good Flap?

PubMed Central

Perdikis, Galen; Koonce, Stephanie; Collis, George; Eck, Dustin

2011-01-01

Objective: This article serves to review latissimus dorsi myocutaneous flap as an option for breast reconstruction postmastectomy. Since the introduction of the latissimus dorsi myocutaneous flap in the late 1970s, its use has always been as a secondary technique, particularly after the development of the transverse rectus abdominus myocutaneous flap in the 1980s. Methods: A literature review of the history of latissimus dorsi myocutaneous flap utilized for breast reconstruction as well as a review of our institution's experience with latissimus dorsi myocutaneous flap and tissue expander placement was performed. Results: There remains a paucity of published studies investigating latissimus dorsi myocutaneous flap for breast reconstruction. Most studies have small numbers and do not utilize tissue expanders. More recently several small studies have been published that show acceptably low complication rates with aesthetically pleasing outcomes when latissimus dorsi myocutaneous flap is employed with a tissue expander. At our institution, we have employed latissimus dorsi myocutaneous flap with tissue expander placement for both delayed and immediate reconstruction with subsequent replacement with a permanent implant with a capsular contraction rate of 10.5%. Our data and others more recently published demonstrate very acceptable capsular contracture rates and aesthetic outcomes, particularly when an expander is utilized. Conclusion: The latissimus dorsi myocutaneous flap remains an excellent choice for breast reconstruction with a low risk of complications. PMID:22031843

Latissimus dorsi myocutaneous flap for breast reconstruction: bad rap or good flap?

PubMed

Perdikis, Galen; Koonce, Stephanie; Collis, George; Eck, Dustin

2011-01-01

This article serves to review latissimus dorsi myocutaneous flap as an option for breast reconstruction postmastectomy. Since the introduction of the latissimus dorsi myocutaneous flap in the late 1970s, its use has always been as a secondary technique, particularly after the development of the transverse rectus abdominus myocutaneous flap in the 1980s. A literature review of the history of latissimus dorsi myocutaneous flap utilized for breast reconstruction as well as a review of our institution's experience with latissimus dorsi myocutaneous flap and tissue expander placement was performed. There remains a paucity of published studies investigating latissimus dorsi myocutaneous flap for breast reconstruction. Most studies have small numbers and do not utilize tissue expanders. More recently several small studies have been published that show acceptably low complication rates with aesthetically pleasing outcomes when latissimus dorsi myocutaneous flap is employed with a tissue expander. At our institution, we have employed latissimus dorsi myocutaneous flap with tissue expander placement for both delayed and immediate reconstruction with subsequent replacement with a permanent implant with a capsular contraction rate of 10.5%. Our data and others more recently published demonstrate very acceptable capsular contracture rates and aesthetic outcomes, particularly when an expander is utilized. The latissimus dorsi myocutaneous flap remains an excellent choice for breast reconstruction with a low risk of complications.

Influence of Flap Thickness on Nipple Projection After Nipple Reconstruction Using a Modified Star Flap.

PubMed

Ishii, Naohiro; Ando, Jiro; Harao, Michiko; Takemae, Masaru; Kishi, Kazuo

2018-05-07

In nipple reconstruction, the width, length, and thickness of modified star flaps are concerns for long-term reconstructed nipple projection. However, the flap's projection has not been analyzed, based on its thickness. The aim of the present study was to investigate how flap thickness in a modified star flap influences the resulting reconstructed nipple and achieves an appropriate flap width in design. Sixty-three patients who underwent nipple reconstruction using a modified star flap following implant-based breast reconstruction between August 2014 and July 2016 were included in this case-controlled study. The length of laterally diverging flaps was 1.5 times their width. The thickness of each flap was measured using ultrasonography, and the average thickness was defined as the flap thickness. We investigated the correlation between the resulting reconstructed nipple and flap thickness, and the difference of the change in the reconstructed nipple projection after using a thin or thick flap. The average flap thickness was 3.8 ± 1.7 (range 2.5-6.0) mm. There was a significant, linear correlation between the flap thickness and resulting reconstructed nipple projection (β = 0.853, p < 0.01). Furthermore, the difference between the thin and thick flaps in the resulting reconstructed nipple projection was significant (p < 0.01). Measuring the flap thickness preoperatively may allow surgeons to achieve an appropriate flap width; otherwise, alternative methods for higher projection might be used. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Heart rate and estimated energy expenditure of flapping and gliding in black-browed albatrosses.

PubMed

Sakamoto, Kentaro Q; Takahashi, Akinori; Iwata, Takashi; Yamamoto, Takashi; Yamamoto, Maki; Trathan, Philip N

2013-08-15

Albatrosses are known to expend only a small amount of energy during flight. The low energy cost of albatross flight has been attributed to energy-efficient gliding (soaring) with sporadic flapping, although little is known about how much time and energy albatrosses expend in flapping versus gliding during cruising flight. Here, we examined the heart rates (used as an instantaneous index of energy expenditure) and flapping activities of free-ranging black-browed albatrosses (Thalassarche melanophrys) to estimate the energy cost of flapping as well as time spent in flapping activities. The heart rate of albatrosses during flight (144 beats min(-1)) was similar to that while sitting on the water (150 beats min(-1)). In contrast, heart rate was much higher during takeoff and landing (ca. 200 beats min(-1)). Heart rate during cruising flight was linearly correlated with the number of wing flaps per minute, suggesting an extra energy burden of flapping. Albatrosses spend only 4.6±1.4% of their time flapping during cruising flight, which was significantly lower than during and shortly after takeoff (9.8±3.5%). Flapping activity, which amounted to just 4.6% of the time in flight, accounted for 13.3% of the total energy expenditure during cruising flight. These results support the idea that albatrosses achieve energy-efficient flight by reducing the time spent in flapping activity, which is associated with high energy expenditure.

Aesthetic Penoscrotal Resurfacing: Creating Propeller Flaps from Gluteal Folds.

PubMed

Han, So-Eun; Kim, Eun-Ji; Sung, Hyun Hwan; Pyon, Jai-Kyong

2018-04-01

Reconstruction of extensive penoscrotal defects is a surgical challenge. Resurfacing defects in highly complex three-dimensional structures and restoring their function are an essential part of the reconstruction of penoscrotal regions. We describe a technique using internal pudendal artery perforator (IPAP) pedicled propeller flaps created from the gluteal fold. This could be a reliable surgical option that maintains a natural looking scrotal pouch with minimal donor site morbidity and optimal sexual activity. We retrospectively reviewed data for 10 consecutive patients who had undergone penoscrotal reconstruction using IPAP pedicled propeller flaps between January 2011 and March 2015. The IPAP was identified using a hand-held Doppler ultrasound device. This was the pivot around which the flap was internally rotated more than 90° in a tension-free manner. The long axis of the flap was centred on the gluteal fold to provide a better-orientated donor site scar. Complications and patient satisfaction with respect to size, colour match, scar appearance, and sexual activity were evaluated. Anatomic and aesthetic penoscrotal reconstruction was performed without any major complications in the follow-up period (mean, 19.7 mo). The mean width of the IPAP pedicled propeller flaps was 6.7cm, and the mean length was 11.7cm. Partial distal flap necrosis occurred in only one case, and healed spontaneously. All of the patients were satisfied with the cosmetic and functional results. On the basis of reliable perforators, donor site morbidity, flap thickness, and a better orientated scar, our technique using IPAP pedicled propeller flaps created from the gluteal fold could be a reasonable surgical option for extensive penoscrotal reconstruction. The creation of pedicled propeller flaps using an internal pudendal artery perforator could be a reliable surgical option for reconstruction of extensive penoscrotal defects. The approach yields functional and aesthetically acceptable

Outcomes of using a modified anteromedial thigh perforator flap for repairing the anterolateral thigh free flap donor site: A retrospective clinical review.

PubMed

Zhou, Xiao; Wang, Jin; Qiang, Li; Rui, Yongjun; Xue, Mingyu

2018-04-01

The anterolateral thigh (ALT) flap plays an essential part in plastic and reconstructive surgery. However, repair of the anterolateral donor site has not been the focus of the clinicians.To assess the clinical value and feasibility of using a modified anteromedial thigh (AMT) perforator flap for repairing the ALT free flap donor site.In this retrospective study, 16 ALT flaps were transferred to resurface large soft-tissue defects (ranged from 7 × 5 to 13 × 8 cm) in the foot or hand from June 2012 to March 2013. The donor sites were repaired with an advancement flap pedicled with an AMT perforator. Sensation within the advancement flap, return-to-work (RTW) time, the aesthetic appearance of the donor sites, and functional recovery were measured.All 15 flaps survived completely without necrosis. One flap developed partial necrosis in the tip but healed with dressing changes after 1 week. The medain follow-up period was 3.5 months (range, 3-6 months). The average median time was 9.5 weeks (range 8-13 weeks). There was no numbness of the advancement flap. Additionally, there was no specific complication at both the recipient and donor sites. Thigh quadriceps muscle strength and activities of the knee were normal. All patients were satisfied with the aesthetic outcome postoperatively at the 3-month to 6-month follow-up.The modified advancement flap pedicled with an AMT perforator is an ideal option for repairing the anterolateral donor site.

Low Speed and High Speed Correlation of SMART Active Flap Rotor Loads

NASA Technical Reports Server (NTRS)

Kottapalli, Sesi B. R.

2010-01-01

Measured, open loop and closed loop data from the SMART rotor test in the NASA Ames 40- by 80- Foot Wind Tunnel are compared with CAMRAD II calculations. One open loop high-speed case and four closed loop cases are considered. The closed loop cases include three high-speed cases and one low-speed case. Two of these high-speed cases include a 2 deg flap deflection at 5P case and a test maximum-airspeed case. This study follows a recent, open loop correlation effort that used a simple correction factor for the airfoil pitching moment Mach number. Compared to the earlier effort, the current open loop study considers more fundamental corrections based on advancing blade aerodynamic conditions. The airfoil tables themselves have been studied. Selected modifications to the HH-06 section flap airfoil pitching moment table are implemented. For the closed loop condition, the effect of the flap actuator is modeled by increased flap hinge stiffness. Overall, the open loop correlation is reasonable, thus confirming the basic correctness of the current semi-empirical modifications; the closed loop correlation is also reasonable considering that the current flap model is a first generation model. Detailed correlation results are given in the paper.

The transverse musculocutaneous gracilis flap for breast reconstruction: guidelines for flap and patient selection.

PubMed

Schoeller, Thomas; Huemer, Georg M; Wechselberger, Gottfried

2008-07-01

The transverse musculocutaneous gracilis (TMG) flap has received little attention in the literature as a valuable alternative source of donor tissue in the setting of breast reconstruction. The authors give an in-depth review of their experience with breast reconstruction using the TMG flap. A retrospective review of 111 patients treated with a TMG flap for breast reconstruction in an immediate or a delayed setting between August of 2002 and July of 2007 was undertaken. Of these, 26 patients underwent bilateral reconstruction and 68 underwent unilateral reconstruction, and 17 patients underwent reconstruction unilaterally with a double TMG flap. Patient age ranged between 24 and 65 years (mean, 37 years). Twelve patients had to be taken back to the operating room because of flap-related problems and nine patients underwent successful revision microsurgically, resulting in three complete flap losses in a series of 111 patients with 154 transplanted TMG flaps. Partial flap loss was encountered in two patients, whereas fat tissue necrosis was managed conservatively in six patients. Donor-site morbidity was an advantage of this flap, with a concealed scar and minimal contour irregularities of the thigh, even in unilateral harvest. Complications included delayed wound healing (n = 10), hematoma (n = 5), and transient sensory deficit over the posterior thigh (n = 49). The TMG flap is more than an alternative to the deep inferior epigastric perforator (DIEP) flap in microsurgical breast reconstruction in selected patients. In certain indications, such as bilateral reconstructions, it possibly surpasses the DIEP flap because of a better concealed donor scar and easier harvest.

[Pedicle flap of nasal septum-basis nasi and temporal muscucofascial flap to repair nasoseptal perforation].

PubMed

Yin, Xinghong; Hu, Wei; Zhang, Xinhai; Sun, Min

2014-10-01

To explore curative effect with pedicle flap of nasal septum-basis nasi and temporal muscucofascial flap to repair nasal septal perforation. Dissecting mucoperichondrium and mucoperioseptum around the perforation and taking dowm and out xia-ward to the floor of nasal cavity to make a inferior extremity pedicle flap. Then,the flap was tumbled and sutured onto raw surface of contralateral side through perforation. Reapplicating autoallergic temporal musculofascial flap to repair another side perforation. Repairing perforation Sin twelve cases were sucessfully healed in endoscope. The pedicle flap of nasal septum-basis nasi and temporal muscucofascial flap is easy to acquire and no rejection. The flap has good blood supplying, high survival rate and provides adequate transplantating materail to repair comparatively large perforation.

Reconstruction of the Foot and Ankle Using Pedicled or Free Flaps: Perioperative Flap Survival Analysis

PubMed Central

Li, Xiucun; Cui, Jianli; Maharjan, Suraj; Lu, Laijin; Gong, Xu

2016-01-01

Objective The purpose of this study is to determine the correlation between non-technical risk factors and the perioperative flap survival rate and to evaluate the choice of skin flap for the reconstruction of foot and ankle. Methods This was a clinical retrospective study. Nine variables were identified. The Kaplan-Meier method coupled with a log-rank test and a Cox regression model was used to predict the risk factors that influence the perioperative flap survival rate. The relationship between postoperative wound infection and risk factors was also analyzed using a logistic regression model. Results The overall flap survival rate was 85.42%. The necrosis rates of free flaps and pedicled flaps were 5.26% and 20.69%, respectively. According to the Cox regression model, flap type (hazard ratio [HR] = 2.592; 95% confidence interval [CI] (1.606, 4.184); P < 0.001) and postoperative wound infection (HR = 0.266; 95% CI (0.134, 0.529); P < 0.001) were found to be statistically significant risk factors associated with flap necrosis. Based on the logistic regression model, preoperative wound bed inflammation (odds ratio [OR] = 11.371,95% CI (3.117, 41.478), P < 0.001) was a statistically significant risk factor for postoperative wound infection. Conclusion Flap type and postoperative wound infection were both independent risk factors influencing the flap survival rate in the foot and ankle. However, postoperative wound infection was a risk factor for the pedicled flap but not for the free flap. Microvascular anastomosis is a major cause of free flap necrosis. To reconstruct complex or wide soft tissue defects of the foot or ankle, free flaps are safer and more reliable than pedicled flaps and should thus be the primary choice. PMID:27930679

Pedicled Temporalis Muscle Flap for Craniofacial Reconstruction: A 35-Year Clinical Experience with 366 Flaps.

PubMed

Spanio di Spilimbergo, Stefano; Nordera, Paolo; Mardini, Samir; Castiglione, Giusy; Chim, Harvey; Pinna, Vittore; Brunello, Massimo; Cusino, Claudio; Roberto, Squaquara; Baciliero, Ugo

2017-02-01

In the past 130 years, the temporalis muscle flap has been used for a variety of different indications. In this age of microsurgery and perforator flaps, the temporalis muscle flap still has many useful applications for craniofacial reconstruction. Three hundred sixty-six temporalis muscle flaps were performed in a single center between 1978 and 2012. The authors divided the cases into two series-before and after 1994-because, after 1994, they started to perform free flap reconstructions, and indications for reconstruction with a temporalis muscle flap were changed RESULTS:: In the series after 1994, flaps were most commonly used for reconstruction of defects in the maxilla, mandible, and oropharynx, in addition to facial reanimation and filling of orbital defects. Complications included total flap necrosis (1.6 percent) and partial flap necrosis (10.7 percent). The rate of material extrusion at the donor site decreased after porous polyethylene was uniformly used for reconstruction from 17.1 to 7.9 percent. The pedicled temporalis muscle flap continues to have many applications in craniofacial reconstruction. With increasing use of free flaps, the authors' indications for the pedicled temporalis muscle flap are now restricted to (1) orbital filling for congenital or acquired anophthalmia; (2) filling of unilateral maxillectomy defects; and (3) facial reanimation in selected cases of facial nerve palsy. Therapeutic, IV.

Dancing girl flap: a new flap suitable for web release.

PubMed

Shinya, K

1999-12-01

To create a deep web, a flap must be designed to have a high elongation effect in one direction along the mid-lateral line of the finger and also to have a shortening effect in the other direction, crossing at a right angle to the mid-lateral line. The dancing girl flap is a modification of a four-flap Z-plasty with two additional Z-plasties. It has a high elongation effect in one direction (>550%) and a shortening effect in the other direction at a right angle (<33%), creating a deep, U-shaped surface. This new flap can be used to release severe scar contracture with a web, and is most suitable for incomplete syndactyly with webs as high as the proximal interphalangeal joint.

PIV Measurements on a Blowing Flap

NASA Technical Reports Server (NTRS)

Hutcheson, Florence V.; Stead, Daniel J.

2004-01-01

PIV measurements of the flow in the region of a flap side edge are presented for several blowing flap configurations. The test model is a NACA 63(sub 2)-215 Hicks Mod-B main-element airfoil with a half-span Fowler flap. Air is blown from small slots located along the flap side edge on either the top, bottom or side surfaces. The test set up is described and flow measurements for a baseline and three blowing flap configurations are presented. The effects that the flap tip jets have on the structure of the flap side edge flow are discussed for each of the flap configurations tested. The results indicate that blowing air from a slot located along the top surface of the flap greatly weakened the top vortex system and pushed it further off the top surface. Blowing from the bottom flap surface kept the strong side vortex further outboard while blowing from the side surface only strengthened the vortex system or accelerated the merging of the side vortex to the flap top surface. It is concluded that blowing from the top or bottom surfaces of the flap may lead to a reduction of flap side edge noise.

Structural insights into 5‧ flap DNA unwinding and incision by the human FAN1 dimer

NASA Astrophysics Data System (ADS)

Zhao, Qi; Xue, Xiaoyu; Longerich, Simonne; Sung, Patrick; Xiong, Yong

2014-12-01

Human FANCD2-associated nuclease 1 (FAN1) is a DNA structure-specific nuclease involved in the processing of DNA interstrand crosslinks (ICLs). FAN1 maintains genomic stability and prevents tissue decline in multiple organs, yet it confers ICL-induced anti-cancer drug resistance in several cancer subtypes. Here we report three crystal structures of human FAN1 in complex with a 5‧ flap DNA substrate, showing that two FAN1 molecules form a head-to-tail dimer to locate the lesion, orient the DNA and unwind a 5‧ flap for subsequent incision. Biochemical experiments further validate our model for FAN1 action, as structure-informed mutations that disrupt protein dimerization, substrate orientation or flap unwinding impair the structure-specific nuclease activity. Our work elucidates essential aspects of FAN1-DNA lesion recognition and a unique mechanism of incision. These structural insights shed light on the cellular mechanisms underlying organ degeneration protection and cancer drug resistance mediated by FAN1.

Lower Extremity Limb Salvage with Cross Leg Pedicle Flap, Cross Leg Free Flap, and Cross Leg Vascular Cable Bridge Flap.

PubMed

Manrique, Oscar J; Bishop, Sarah N; Ciudad, Pedro; Adabi, Kian; Martinez-Jorge, Jorys; Moran, Steven L; Huang, Tony; Vijayasekaran, Aparna; Chen, Shih-Heng; Chen, Hung-Chi

2018-05-16

 Lower extremity salvage following significant soft tissue loss can be complicated by lack of recipient vessel for free tissue transfer. We describe our experience in lower limb salvage for patients with no recipient vessels with the use of pedicle, free and cable bridge flaps.  A retrospective review from 1985 to 2017 of patients undergoing lower limb salvage using a contralateral pedicle cross leg (PCL) flaps, free cross leg (FCL) flaps, or free cable bridge (FCB) flaps was conducted. Demographics, etiology of the reconstruction, type of flap used, donor-site vessels, defect size, operating time, time of pedicle division, length of hospital stay, time to ambulation, and complications were analyzed.  A total of 53 patients (48 males and 5 females) with an average age of 35 years (range, 29-38 years) were identified. The etiology for the reconstruction was trauma in 52 patients and oncological resection in 1 patient. There were 18 PCL, 25 FCL, and 10 FCB completed. The recipient vessels for all flaps were the posterior tibial artery and vein. The average operating room times for PCL, FCL, and FCB flaps were 4, 9, and 10 hours, respectively. The average length of hospital stay was 5 weeks and average time to ambulation was 4 weeks. The average follow-up time was 7.5 years (range, 3-12 years). Complications encountered were hematoma (six), prolonged pain (six), total flap loss (two), reoperation (five), and infection (four). Limb salvage rates were 96.2%.  When ipsilateral limb vessels are not available, and other reconstructive options have been exhausted, cross leg flaps can be a viable option for limb salvage in the setting of extensive defects. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Navier-Stokes Computations of a Wing-Flap Model With Blowing Normal to the Flap Surface

NASA Technical Reports Server (NTRS)

Boyd, D. Douglas, Jr.

2005-01-01

A computational study of a generic wing with a half span flap shows the mean flow effects of several blown flap configurations. The effort compares and contrasts the thin-layer, Reynolds averaged, Navier-Stokes solutions of a baseline wing-flap configuration with configurations that have blowing normal to the flap surface through small slits near the flap side edge. Vorticity contours reveal a dual vortex structure at the flap side edge for all cases. The dual vortex merges into a single vortex at approximately the mid-flap chord location. Upper surface blowing reduces the strength of the merged vortex and moves the vortex away from the upper edge. Lower surface blowing thickens the lower shear layer and weakens the merged vortex, but not as much as upper surface blowing. Side surface blowing forces the lower surface vortex farther outboard of the flap edge by effectively increasing the aerodynamic span of the flap. It is seen that there is no global aerodynamic penalty or benefit from the particular blowing configurations examined.

Edaravone enhances the viability of ischemia/reperfusion flaps.

PubMed

Zhang, Dong-Yi; Kang, Shen-Song; Zhang, Zheng-Wen; Wu, Rui

2017-02-01

The purpose of the experiment was to study the efficacy of edaravone in enhancing flap viability after ischemia/reperfusion (IR) and its mechanism. Forty-eight adult male SD rats were randomly divided into 3 groups: control group (n=16), IR group (n=16), and edaravone-treated IR group (n=16). An island flap at left lower abdomen (6.0 cm×3.0 cm in size), fed by the superficial epigastric artery and vein, was created in each rat of all the three groups. The arterial blood flow of flaps in IR group and edaravone-treated IR group was blocked for 10 h, and then the blood perfusion was restored. From 15 min before reperfusion, rats in the edaravone-treated IR group were intraperitoneally injected with edaravone (10 mg/kg), once every 12 h, for 3 days. Rats in the IR group and control group were intraperitoneally injected with saline, with the same method and frequency as the rats in the edaravone-treated IR group. In IR group and edaravone-treated IR group, samples of flaps were harvested after reperfusion of the flaps for 24 h. In the control group, samples of flaps were harvested 34 h after creation of the flaps. The content of malondialdehyde (MDA) and activity of superoxide dismutase (SOD) were determined, and changes in organizational structure and infiltration of inflammatory cells were observed by hematoxylin-eosin (HE) staining, apoptotic cells of vascular wall were marked by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, and the apoptotic rate of cells in vascular wall was calculated. The ultrastructural changes of vascular endothelial cells were observed by transmission electron microscopy (TEM). Seven days after the operation, we calculated the flap viability of each group, and marked vessels of flaps by immunohistochemical staining for calculating the average number of subcutaneous vessels. The results showed that the content of MDA, the number of multicore inflammatory cells and apoptotic rate of cells in vascular wall

The "Tokyo" consensus on propeller flaps.

PubMed

Pignatti, Marco; Ogawa, Rei; Hallock, Geoffrey G; Mateev, Musa; Georgescu, Alexandru V; Balakrishnan, Govindasamy; Ono, Shimpei; Cubison, Tania C S; D'Arpa, Salvatore; Koshima, Isao; Hyakusoku, Hikko

2011-02-01

Over the past few years, the use of propeller flaps, which base their blood supply on subcutaneous tissue or isolated perforators, has become increasingly popular. Because no consensus has yet been reached on terminology and nomenclature of the propeller flap, different and confusing uses of the term can be found in the literature. In this article, the authors report the consensus on the definition and classification of propeller flaps reached by the authors that gathered at the First Tokyo Meeting on Perforator and Propeller Flaps in June of 2009. Some peculiar aspects of the surgical technique are discussed. A propeller flap can be defined as an "island flap that reaches the recipient site through an axial rotation." The classification is based on the nourishing pedicle (subcutaneous pedicled propeller flap, perforator pedicled propeller flap, supercharged propeller flap), the degrees of skin island rotation (90 to 180 degrees) and, when possible, the artery of origin of the perforator. The propeller flap is a useful reconstructive tool that can achieve good cosmetic and functional results. A flap should be called a propeller flap only if it fulfils the definition above. The type of nourishing pedicle, the source vessel (when known), and the degree of skin island rotation should be specified for each flap.

Noise Reduction of Aircraft Flap

NASA Technical Reports Server (NTRS)

Hutcheson, Florence V. (Inventor); Brooks, Thomas F. (Inventor)

2009-01-01

A reduction in noise radiating from a side of a deployed aircraft flap is achieved by locating a slot adjacent the side of the flap, and then forcing air out through the slot with a suitable mechanism. One, two or even three or more slots are possible, where the slot is located at one;or more locations selected from a group of locations comprising a top surface of the flap, a bottom surface of the flap, an intersection of the top and side surface of the flap, an intersection of the bottom and side surfaces of the flap, and a side surface of the flap. In at least one embodiment the slot is substantially rectangular. A device for adjusting a rate of the air forced out through the slot can also be provided.

New model of flap-gliding flight.

PubMed

Sachs, Gottfried

2015-07-21

A new modelling approach is presented for describing flap-gliding flight in birds and the associated mechanical energy cost of travelling. The new approach is based on the difference in the drag characteristics between flapping and non-flapping due to the drag increase caused by flapping. Thus, the possibility of a gliding flight phase, as it exists in flap-gliding flight, yields a performance advantage resulting from the decrease in the drag when compared with continuous flapping flight. Introducing an appropriate non-dimensionalization for the mathematical relations describing flap-gliding flight, results and findings of generally valid nature are derived. It is shown that there is an energy saving of flap-gliding flight in the entire speed range compared to continuous flapping flight. The energy saving reaches the highest level in the lower speed region. The travelling speed of flap-gliding flight is composed of the weighted average of the differing speeds in the flapping and gliding phases. Furthermore, the maximum range performance achievable with flap-gliding flight and the associated optimal travelling speed are determined. Copyright © 2015 Elsevier Ltd. All rights reserved.

Management of Dropped Skull Flaps.

PubMed

Abdelfatah, Mohamed AbdelRahman

2017-01-01

Dropping a skull flap on the floor is an uncommon and avoidable mistake in the neurosurgical operating theater. This study retrospectively reviewed all incidents of dropped skull flaps in Ain-Shams University hospitals during a 10-year period to show how to manage this problem and its outcome. Thirty-one incidents of dropped skull flaps occurred from January 2004 to January 2014 out of more than 10,000 craniotomies. Follow-up period varied from 20 to 44 months. The bone flap was dropped while elevating the bone (n = 16), while drilling the bone on the operating table (n = 5), and during insertion of the bone flap (n = 10). Treatment included re-insertion of the skull flap after soaking it in povidone iodine and antibiotic solution (n = 17) or after autoclaving (n = 11), or discarding the skull flap and replacing it with a mesh cranioplasty in the same operation (n = 3). No bone or wound infection was noted during the follow-up period. Management of dropped skull flap is its prevention. Replacement of the skull flap, after decontamination, is an option that avoids the expense and time of cranioplasty.

Decellularized skin/adipose tissue flap matrix for engineering vascularized composite soft tissue flaps.

PubMed

Zhang, Qixu; Johnson, Joshua A; Dunne, Lina W; Chen, Youbai; Iyyanki, Tejaswi; Wu, Yewen; Chang, Edward I; Branch-Brooks, Cynthia D; Robb, Geoffrey L; Butler, Charles E

2016-04-15

Using a perfusion decellularization protocol, we developed a decellularized skin/adipose tissue flap (DSAF) comprising extracellular matrix (ECM) and intact vasculature. Our DSAF had a dominant vascular pedicle, microcirculatory vascularity, and a sensory nerve network and retained three-dimensional (3D) nanofibrous structures well. DSAF, which was composed of collagen and laminin with well-preserved growth factors (e.g., vascular endothelial growth factor, basic fibroblast growth factor), was successfully repopulated with human adipose-derived stem cells (hASCs) and human umbilical vein endothelial cells (HUVECs), which integrated with DSAF and formed 3D aggregates and vessel-like structures in vitro. We used microsurgery techniques to re-anastomose the recellularized DSAF into nude rats. In vivo, the engineered flap construct underwent neovascularization and constructive remodeling, which was characterized by the predominant infiltration of M2 macrophages and significant adipose tissue formation at 3months postoperatively. Our results indicate that DSAF co-cultured with hASCs and HUVECs is a promising platform for vascularized soft tissue flap engineering. This platform is not limited by the flap size, as the entire construct can be immediately perfused by the recellularized vascular network following simple re-integration into the host using conventional microsurgical techniques. Significant soft tissue loss resulting from traumatic injury or tumor resection often requires surgical reconstruction using autologous soft tissue flaps. However, the limited availability of qualitative autologous flaps as well as the donor site morbidity significantly limits this approach. Engineered soft tissue flap grafts may offer a clinically relevant alternative to the autologous flap tissue. In this study, we engineered vascularized soft tissue free flap by using skin/adipose flap extracellular matrix scaffold (DSAF) in combination with multiple types of human cells. Following

Face resurfacing using a cervicothoracic skin flap prefabricated by lateral thigh fascial flap and tissue expander.

PubMed

Li, Qingfeng; Zan, Tao; Gu, Bin; Liu, Kai; Shen, Guoxiong; Xie, Yun; Weng, Rui

2009-01-01

Resurfacing of facial massive soft tissue defect is a formidable challenge because of the unique character of the region and the limitation of well-matched donor site. In this report, we introduce a technique for using the prefabricated cervicothoracic skin flap for facial resurfacing, in an attempt to meet the principle of flap selection in face reconstructive surgery for matching the color and texture, large dimension, and thinner thickness (MLT) of the recipient. Eleven patients with massive facial scars underwent resurfacing procedures with prefabricated cervicothoracic flaps. The vasculature of the lateral thigh fascial flap, including the descending branch of the lateral femoral circumflex vessels and the surrounding muscle fascia, was used as the vascular carrier, and the pedicles of the fascial flap were anastomosed to either the superior thyroid or facial vessels in flap prefabrication. A tissue expander was placed beneath the fascial flap to enlarge the size and reduce the thickness of the flap. The average size of the harvested fascia flap was 6.5 x 11.7 cm. After a mean interval of 21.5 weeks, the expanders were filled to a mean volume of 1,685 ml. The sizes of the prefabricated skin flaps ranged from 12 x 15 cm to 15 x 32 cm. The prefabricated skin flaps were then transferred to the recipient site as pedicled flaps for facial resurfacing. All facial soft tissue defects were successfully covered by the flaps. The donor sites were primarily closed and healed without complications. Although varied degrees of venous congestion were developed after flap transfers, the marginal necrosis only occurred in two cases. The results in follow-up showed most resurfaced faces restored natural contour and regained emotional expression. MLT is the principle for flap selection in resurfacing of the massive facial soft tissue defect. Our experience in this series of patients demonstrated that the prefabricated cervicothoracic skin flap could be a reliable alternative

Propeller flaps in eyelid reconstruction.

PubMed

Rajak, Saul N; Huilgol, Shyamala C; Murakami, Masahiro; Selva, Dinesh

2018-03-14

Propeller flaps are island flaps that reach the recipient site through an axial rotation. The flap has a subcutaneous pedicle on which it pivots, thereby resembling a helicopter propeller. We present our series of propeller flaps for the reconstruction of large eyelid defects. This is a retrospective review of the clinical case notes of eight patients that underwent tumour excision with reconstruction with a cutaneous propeller flap supplied by a non-perforator orbicularis pedicle between July and December 2016. Propeller flaps were used in the reconstruction of five lower lid defects (size range 19 × 5 mm to 25 × 8 mm), one medial canthus defect (13 mm diameter), one complete upper lid defect (42 × 19 mm diameter) and one lid sparing extenteration defect. The flaps were recruited from nasolabial, lateral canthal, temple or medial upper cheek skin. Post-operatively one case had 'trapdooring' which required flap revision at 4 months and one had persistent oedema that settled without intervention. The reconstruction of large eyelid defects is challenging in part because of the paucity of locally available skin. Propeller flaps are a paradigm shift in periocular reconstruction in which the subcutaneous pedicle enables the recruitment of large and highly mobile skin flaps from a wide area of regional tissue.

Prostaglandins inhibit 5-lipoxygenase-activating protein expression and leukotriene B4 production from dendritic cells via an IL-10-dependent mechanism.

PubMed

Harizi, Hedi; Juzan, Monique; Moreau, Jean-François; Gualde, Norbert

2003-01-01

PGs produced from arachidonic acid by the action of cyclooxygenase enzymes play a pivotal role in the regulation of both inflammatory and immune responses. Because leukotriene B4 (LTB4), a product of 5-lipoxygenase (5-LO) pathway, can exert numerous immunoregulatory and proinflammatory activities, we examined the effects of PGs on LTB4 release from dendritic cells (DC) and from peritoneal macrophages. In concentration-dependent manner, PGE1 and PGE2 inhibited the production of LTB4 from DC, but not from peritoneal macrophage, with an IC50 of 0.04 microM. The same effect was observed with MK-886, a 5-LO-activating protein (FLAP)-specific inhibitor. The decreased release of LTB4 was associated with an enhanced level of IL-10. Furthermore, the inhibition of LTB4 synthesis by PGs was significantly reversed by anti-IL-10, suggesting the involvement of an IL-10-dependent mechanism. Hence, we examined the effects of exogenous IL-10 on the 5-LO pathway. We demonstrate that IL-10 suppresses the production of LTB4 from DC by inhibiting FLAP protein expression without any effect on 5-LO and cytosolic phospholipase A2. Taken together, our results suggest links between DC cyclooxygenase and 5-LO pathways during the inflammatory response, and FLAP is a key target for the PG-induced IL-10-suppressive effects.

Comparison of gluteal perforator flaps and gluteal fasciocutaneous rotation flaps for reconstruction of sacral pressure sores.

PubMed

Chen, Yen-Chou; Huang, Eng-Yen; Lin, Pao-Yuan

2014-03-01

The gluteus maximus myocutaneous flap was considered the workhorse that reconstructed sacral pressure sores, but was gradually replaced by fasciocutaneous flap because of several disadvantages. With the advent of the perforator flap technique, gluteal perforator (GP) flap has gained popularity nowadays. The aim of this study was to compare the complications and outcomes between GP flaps and gluteal fasciocutaneous rotation (FR) flaps in the treatment of sacral pressure sores. Between April 2007 and June 2012, 63 patients underwent sacral pressure sore reconstructions, with a GP flap used in 31 cases and an FR flap used in 32 cases. Data collected on the patients included patient age, gender, co-morbidity for being bedridden and follow-up time. Surgical details collected included the defect size, operative time and estimated blood loss. Complications recorded included re-operation, dehiscence, flap necrosis, wound infection, sinus formation, donor-site morbidity and recurrence. The complications and clinical outcomes were compared between these two groups. We found that there was no significant difference in patient demographics, surgical complications and recurrence between these two groups. In gluteal FR flap group, all recurrent cases (five) were treated by reuse of previous flaps. Both methods are comparable, good and safe in treating sacral pressure sores. Gluteal FR flap can be performed without microsurgical dissection, and re-rotation is feasible in recurrent cases. The authors suggest using gluteal FR flaps in patients with a high risk of sore recurrence. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Vibration reduction in helicopter rotors using an actively controlled partial span trailing edge flap located on the blade

NASA Technical Reports Server (NTRS)

Millott, T. A.; Friedmann, P. P.

1994-01-01

This report describes an analytical study of vibration reduction in a four-bladed helicopter rotor using an actively controlled, partial span, trailing edge flap located on the blade. The vibration reduction produced by the actively controlled flap (ACF) is compared with that obtained using individual blade control (IBC), in which the entire blade is oscillated in pitch. For both cases a deterministic feedback controller is implemented to reduce the 4/rev hub loads. For all cases considered, the ACF produced vibration reduction comparable with that obtained using IBC, but consumed only 10-30% of the power required to implement IBC. A careful parametric study is conducted to determine the influence of blade torsional stiffness, spanwise location of the control flap, and hinge moment correction on the vibration reduction characteristics of the ACF. The results clearly demonstrate the feasibility of this new approach to vibration reduction. It should be emphasized than the ACF, used together with a conventional swashplate, is completely decoupled from the primary flight control system and thus it has no influence on the airworthiness of the helicopter. This attribute is potentially a significant advantage when compared to IBC.

On the generation of side-edge flap noise. [part span trailing edge flaps

NASA Technical Reports Server (NTRS)

Howe, M. S.

1981-01-01

A theory is proposed for estimating the noise generated at the side edges of part span trailing edge flaps in terms of pressure fluctuations measured just in-board of the side edge of the upper surface of the flap. Asymptotic formulae are developed in the opposite extremes of Lorentz contracted acoustic wavelength large/small compared with the chord of the flap. Interpolation between these limiting results enables the field shape and its dependence on subsonic forward flight speed to be predicted over the whole frequency range. It is shown that the mean width of the side edge gap between the flap and the undeflected portion of the airfoil has a significant influence on the intensity of the radiated sound. It is estimated that the noise generated at a single side edge of a full scale part span flap can exceed that produced along the whole of the trailing edge of the flap by 3 dB or more.

Use of active control systems to improve bending and rotor flapping response of a tilt rotor VTOL airplane

NASA Technical Reports Server (NTRS)

Whitaker, H. P.; Cheng, Y.

1975-01-01

The results are summarized of an analytical study of the use of active control systems for the purpose of reducing the root mean square response of wing vertical bending and rotor flapping to atmospheric turbulence for a tilt-rotor VTOL airplane. Only the wing/rotor assembly was considered so that results of a wind tunnel test program would be applicable in a subsequent phase of the research. The capabilities and limitations of simple single feedback configurations were identified, and the most promising multiloop feedback configurations were then investigated. Design parameters were selected so as to minimize either wing bending or rotor flapping response. Within the constraints imposed by practical levels of feedback gains and complexity and by considerations of safety, reduction in response due to turbulence of the order of 30 to 50 percent is predicted using the rotor longitudinal cyclic and a trailing edge wing flap as control effectors.

Foucher first dorsal metacarpal artery flap versus littler heterodigital neurovascular flap in resurfacing thumb pulp loss defects.

PubMed

Delikonstantinou, Iraklis P; Gravvanis, Andreas I; Dimitriou, Vasilios; Zogogiannis, Ioannis; Douma, Amalia; Tsoutsos, Dimosthenis A

2011-08-01

Our study aims to illustrate the advantages and disadvantages of Foucher's first dorsal metacarpal artery flap and Littler's heterodigital neurovascular flap in thumb pulp reconstruction, by assessing wound healing of donor and recipient sites, sensibility, and functional outcome of the reconstructed thumb. Fourteen male patients were reconstructed either with Foucher (n = 8) or Littler flap (n = 6). Dissection of Foucher's flap was faster than that of Littler's flap. All Littler flaps survived completely, but we experienced 1 partial Foucher flap necrosis. Thumb motility and stability was optimal in all patients. Wound healing of donor sites was achieved in both groups. Two patients reconstructed with Littler flap developed scar contractures and presented a reduced range of motion of donor finger and first webspace, respectively. Although Littler flap resulted in better sensibility and tactile gnosis of the reconstructed thumb-pulp, Foucher flap ensured negligible donor site morbidity, complete cortical reorientation, and better overall hand function.

Molecular Dynamics Simulations of Ligand-Induced Flap Conformational Changes in Cathepsin-D-A Comparative Study.

PubMed

Arodola, Olayide A; Soliman, Mahmoud E S

2016-11-01

The flap region in aspartic proteases is a unique structural feature to this class of enzymes, and found to have a profound impact on protein overall structure, function, and dynamics. Understanding the structure and dynamic behavior of the flap regions is crucial in the design of selective inhibitors against aspartic proteases. Cathepsin-D, an aspartic protease enzyme, has been implicated in a long list of degenerative diseases as well as breast cancer progression. Presented herein, for the first time, is a comprehensive description of the conformational flap dynamics of cathepsin-D using a comparative 50 ns "multiple" molecular dynamics simulations. Diverse collective metrics were proposed to accurately define flap dynamics. These are distance d1 between the flap tips residues (Gly79 and Met301); dihedral angle ϕ; in addition to TriCα angles Gly79-Asp33-Asp223, θ1 , and Gly79-Asp223-Met301, θ2 . The maximum distance attained throughout the simulation was 17.42 and 11.47 Å for apo and bound cathepsin-D, respectively, while the minimum distance observed was 8.75 and 6.32 Å for apo and bound cathepsin-D, respectively. The movement of the flap as well as the twist of the active pocket can properly be explained by measuring the angle, θ1 , between Gly79-Asp33-Met301 and correlating it with the distance Cα of the flap tip residues. The asymmetrical opening of the binding cavity was best described by the large shift of -6.26° to +20.94° in the dihedral angle, ϕ, corresponding to the full opening of the flap at a range of 31-33 ns. A wide-range of post-dynamic analyses was also applied in this report to supplement our findings. We believe that this report would augment current efforts in designing potent structure-based inhibitors against cathepsin-D in the treatment of breast cancer and other degenerative diseases. J. Cell. Biochem. 117: 2643-2657, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Comparison of Dorsal Intercostal Artery Perforator Propeller Flaps and Bilateral Rotation Flaps in Reconstruction of Myelomeningocele Defects.

PubMed

Tenekeci, Goktekin; Basterzi, Yavuz; Unal, Sakir; Sari, Alper; Demir, Yavuz; Bagdatoglu, Celal; Tasdelen, Bahar

2018-04-09

Bilateral rotation flaps are considered the workhorse flaps in reconstruction of myelomeningocele defects. Since the introduction of perforator flaps in the field of reconstructive surgery, perforator flaps have been used increasingly in the reconstruction of various soft tissue defects all over the body because of their appreciated advantages. The aim of this study was to compare the complications and surgical outcomes between bilateral rotation flaps and dorsal intercostal artery perforator (DICAP) flaps in the soft tissue reconstruction of myelomeningocele defects. Between January 2005-February 2017, we studied 47 patients who underwent reconstruction of myelomeningocele defects. Patient demographics, operative data, and postoperative data were reviewed retrospectively and are included in the study. We found no statistically significant differences in patient demographics and surgical complications between these two groups; this may be due to small sample size. With regard to complications-partial flap necrosis, cerebrospinal fluid (CSF) leakage, necessity for reoperation, and wound infection-DICAP propeller flaps were clinically superior to rotation flaps. Partial flap necrosis was associated with CSF leakage and wound infection, and CSF leakage was associated with wound dehiscence. Although surgical outcomes obtained with DICAP propeller flaps were clinically superior to those obtained with rotation flaps, there was no statistically significant difference between the two patient groups. A well-designed comparative study with adequate sample size is needed. Nonetheless, we suggest using DICAP propeller flaps for reconstruction of large myelomeningocele defects.

Externally-blown-flap noise

NASA Technical Reports Server (NTRS)

Dorsch, R. G.; Kreim, W. J.; Olsen, W. A.

1972-01-01

Noise data were obtained with a large externally blown flap model. A fan-jet engine exhaust was simulated by a 1/2-scale bypass nozzle supplied by pressurized air. The nozzle was pylon mounted on a wing section having a double-slotted flap for lift augmentation. Noise radiation patterns and spectra were obtained for nozzle exhaust velocities between 400 and 1150 ft/sec. The blown flap noise data are in good agreement with previous small model results extrapolated to test conditions by Strouhal scaling. The results indicate that blown flap noise must be suppressed to meet STOL aircraft noise goals.

Superficial ulnar artery perforator flap.

PubMed

Schonauer, Fabrizio; Marlino, Sergio; Turrà, Francesco; Graziano, Pasquale; Dell'Aversana Orabona, Giovanni

2014-09-01

Superficial ulnar artery is a rare finding but shows significant surgical implications. Its thinness and pliability make this flap an excellent solution for soft tissue reconstruction, especially in the head and neck region. We hereby report a successful free superficial ulnar artery perforator forearm flap transfer for tongue reconstruction. A 64-year-old man presenting with a squamous cell carcinoma of the left tongue underwent a wide resection of the tumor, left radical neck dissection, and reconstruction of the tongue and the left tonsillar pillar with the mentioned flap. No complications were observed postoperatively. The flap survived completely; no recurrence at 6 months of follow-up was detected. Superficial ulnar artery perforator flap has shown to be a safe alternative to other free tissue flaps in specific forearm anatomic conditions.

Free-style Deepithelialized Propeller Flaps: An Ideal Local Flap to Obliterate Wounds with Dead Space.

PubMed

Datli, Asli; Suh, HyunSuk; Kim, Young Chul; Choi, Doon Hoon; Hong, Joon Pio Jp

2017-03-01

The reconstruction of the posterior trunk, especially with large dead spaces, remains challenging. Regional muscle flaps may lack adequate volume and reach. The purpose of this report was to evaluate the efficacy of deepithelialized free-style perforator-based propeller flaps to obliterate defects with large dead space. A total of 7 patients with defects on the posterior trunk with large dead spaces were evaluated. After complete debridement or resection, all flaps were designed on a single perforator adjacent to the defect, deepithelialized, and then rotated in a propeller fashion. Flaps were further modified in some cases such as folding the flap after deepithelialization to increase bulk and to obliterate the dead space. The flap dimension ranged from 10 × 5 × 1 to 15 × 8 × 2.5 cm based on a single perforator. The rotation arch of the flap ranged from 90 to 180 degrees. Uneventful healing was noted in all cases. One case showed latent redness and swelling at 7 months after falling down, which resolved with medication. During the average follow-up of 28 months, there were no other flap and donor site complications. The deepithelialized propeller flap can be used efficiently to obliterate dead spaces in the posterior trunk and retains advantages such as having a good vascular supply, adequate bulk, sufficient reach without tension, and minimal donor site morbidity.

4‑Phenylbutyrate protects rat skin flaps against ischemia‑reperfusion injury and apoptosis by inhibiting endoplasmic reticulum stress.

PubMed

Yue, Zhen-Shuang; Zeng, Lin-Ru; Quan, Ren-Fu; Tang, Yang-Hua; Zheng, Wen-Jie; Qu, Gang; Xu, Can-Da; Zhu, Fang-Bing; Huang, Zhong-Ming

2016-02-01

4‑phenylbutyrate (4‑PBA) is a low molecular weight fatty acid, which has been demonstrated to regulate endoplasmic reticulum (ER) stress. ER stress‑induced cell apoptosis has an important role in skin flap ischemia; however, a pharmacological approach for treating ischemia‑induced ER dysfunction has yet to be reported. In the present study, the effects of 4‑PBA‑induced ER stress inhibition on ischemia‑reperfusion injury were investigated in the skin flap of rats, and transcriptional regulation was examined. 4‑PBA attenuated ischemia‑reperfusion injury and inhibited cell apoptosis in the skin flap. Furthermore, 4‑PBA reversed the increased expression levels of two ER stress markers: CCAAT/enhancer-binding protein‑homologous protein and glucose‑regulated protein 78. These results suggested that 4‑PBA was able to protect rat skin flaps against ischemia‑reperfusion injury and apoptosis by inhibiting ER stress marker expression and ER stress‑mediated apoptosis. The beneficial effects of 4‑PBA may prove useful in the treatment of skin flap ischemia‑reperfusion injury.

Unraveling HIV protease flaps dynamics by Constant pH Molecular Dynamics simulations.

PubMed

Soares, Rosemberg O; Torres, Pedro H M; da Silva, Manuela L; Pascutti, Pedro G

2016-08-01

The active site of HIV protease (HIV-PR) is covered by two flaps. These flaps are known to be essential for the catalytic activity of the HIV-PR, but their exact conformations at the different stages of the enzymatic pathway remain subject to debate. Understanding the correct functional dynamics of the flaps might aid the development of new HIV-PR inhibitors. It is known that, the HIV-PR catalytic efficiency is pH-dependent, likely due to the influence of processes such as charge transfer and protonation/deprotonation of ionizable residues. Several Molecular Dynamics (MD) simulations have reported information about the HIV-PR flaps. However, in MD simulations the protonation of a residue is fixed and thus it is not possible to study the correlation between conformation and protonation state. To address this shortcoming, this work attempts to capture, through Constant pH Molecular Dynamics (CpHMD), the conformations of the apo, substrate-bound and inhibitor-bound HIV-PR, which differ drastically in their flap arrangements. The results show that the HIV-PR flaps conformations are defined by the protonation of the catalytic residues Asp25/Asp25' and that these residues are sensitive to pH changes. This study suggests that the catalytic aspartates can modulate the opening of the active site and substrate binding. Copyright © 2016 Elsevier Inc. All rights reserved.

Venous coupler use for free-flap breast reconstructions: specific analyses of TMG and DIEP flaps.

PubMed

Bodin, Frédéric; Brunetti, Stefania; Dissaux, Caroline; Erik, A Sauleau; Facca, Sybille; Bruant-Rodier, Catherine; Liverneaux, Philippe

2015-05-01

The purpose of this report was to present the results of comparisons of anastomotic data and flap complications in the use of venous coupler in breast reconstruction with the transverse musculocutaneous gracilis (TMG) flap and the deep inferior epigastric perforator (DIEP) flap. Over a three-year period, 95 patients suffering from breast cancer were treated with mastectomy and breast reconstruction using free flaps. We performed 121 mechanical venous anastomoses for 105 flap procedures (80 DIEP and 25 TMG). The coupler size, anastomotic duration, number of anastomoses and postoperative complications were assessed for the entire series. The coupling device was perfectly suitable for all end-to-end anastomoses between the vein(s) of the flap and the internal mammary vein(s). No venous thrombosis occurred. The mean anastomotic time did not significantly differ between the DIEP (330 seconds) and TMG flap procedures (352 seconds) (P = 0.069). Additionally, there were no differences in coupling time observed following a comparison of seven coupler sizes (P = 0.066). The mean coupler size used during the TMG flap procedure was smaller than that used with the DIEP (2.4 mm versus 2.8 mm) (P < 0.001). The mean size was also smaller when double venous anastomoses were required compared to single anastomosis (2.4 mm versus 2.9 mm) (P < 0.001). The double branching was more frequent with the TMG flap (28%) than with the DIEP flap (11%). The coupler size used was smaller for the TMG procedure and when double venous anastomosis was performed. Additionally, anastomotic time was not affected by the flap type or coupler size used or by anastomosis number. © 2014 Wiley Periodicals, Inc.

Effects of lidocaine on random skin flap survival in rats.

PubMed

Cao, Bin; Wang, Liren; Lin, Dingsheng; Cai, Leyi; Gao, Weiyang

2015-01-01

Use of a random skin flap is common for repairing wounds and for reconstruction. Lidocaine is a traditional local anesthetic that blocks sodium channels and has positive effects on ischemia-reperfusion injury. To investigate the effects of lidocaine on random skin flap survival in rats. McFarlane flaps were established in 20 rats divided into 2 groups. Lidocaine was injected in the lidocaine group, and the same concentration of saline was injected in the control group. The survival area of the flaps was measured on Day 7. Levels of inflammation were evaluated by hematoxylin and eosin (H&E)-stained slices, and superoxide dismutase and malonyldialdehyde contents were examined. The mean survival area of the flaps in the lidocaine group was significantly larger than that in the control group. Superoxide dismutase activity increased significantly in the lidocaine group compared with that in the control group. Malonyldialdehyde level in the lidocaine group was significantly lower than that in the control group. The H&E-stained slices showed that inflammation was clearly inhibited in the lidocaine group. Lidocaine improved the survival of random skin flaps.

Optimal propulsive flapping in Stokes flows.

PubMed

Was, Loïc; Lauga, Eric

2014-03-01

Swimming fish and flying insects use the flapping of fins and wings to generate thrust. In contrast, microscopic organisms typically deform their appendages in a wavelike fashion. Since a flapping motion with two degrees of freedom is able, in theory, to produce net forces from a time-periodic actuation at all Reynolds numbers, we compute in this paper the optimal flapping kinematics of a rigid spheroid in a Stokes flow. The hydrodynamics for the force generation and energetics of the flapping motion is solved exactly. We then compute analytically the gradient of a flapping efficiency in the space of all flapping gaits and employ it to derive numerically the optimal flapping kinematics as a function of the shape of the flapper and the amplitude of the motion. The kinematics of optimal flapping are observed to depend weakly on the flapper shape and are very similar to the figure-eight motion observed in the motion of insect wings. Our results suggest that flapping could be a exploited experimentally as a propulsion mechanism valid across the whole range of Reynolds numbers.

Propeller Flaps: A Literature Review.

PubMed

Sisti, Andrea; D'Aniello, Carlo; Fortezza, Leonardo; Tassinari, Juri; Cuomo, Roberto; Grimaldi, Luca; Nisi, Giuseppe

2016-01-01

Since their introduction in 1991, propeller flaps are increasingly used as a surgical approach to loss of substance. The aim of this study was to evaluate the indications and to verify the outcomes and the complication rates using this reconstructing technique through a literature review. A search on PubMed was performed using "propeller flap", "fasciocutaneous flap", "local flap" or "pedicled flap" as key words. We selected clinical studies using propeller flaps as a reconstructing technique. We found 119 studies from 1991 to 2015. Overall, 1,315 propeller flaps were reported in 1,242 patients. Most frequent indications included loss of substance following tumor excision, repair of trauma-induced injuries, burn scar contractures, pressure sores and chronic infections. Complications were observed in 281/1242 patients (22.6%) occurring more frequently in the lower limbs (31.8%). Partial flap necrosis and venous congestion were the most frequent complications. The complications' rate was significantly higher in infants (<10 years old) and in the older population (>70 years old) but there was not a significant difference between the sexes. Trend of complication rate has not improved during the last years. Propeller flaps showed a great success rate with low morbidity, quick recovery, good aesthetic outcomes and reduced cost. The quality and volume of the transferred soft tissue, the scar orientation and the possibility of direct donor site closure should be considered in order to avoid complications. Indications for propeller flaps are small- or medium-sized defects located in a well-vascularized area with healthy surrounding tissues. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

[A variant of island flaps for the covering of pressure sores: the hatchet flap. Apropos of 31 cases].

PubMed

Quillot, M; Lodde, J P; Pegorier, O; Reynaud, J P; Cormerais, A

1994-08-01

The authors propose a modification of the classical design of island flaps for cover of pressure sores, applied to gluteus maximus and tensor fascia lata muscles: the hatchet flap. 31 flaps have been used including 13 gluteus maximus superior flaps for sacral pressure sores, 9 gluteal inferior flaps for ischial pressure sores and 9 tensor fascia lata flaps for trochanteric pressure sores. A small partial necrosis and two cases of sepsis were observed in this series, but did not require surgical revision. The authors emphasize the value of this modification of the classical flap design, which preserves an even better musculocutaneous capital in these patients, who are often already multi-operated. The very rapid recovery of patients supports the authors' application of hatchet flaps to the surgery of pressure sores, and suggests the extension to other musculocutaneous flaps in the future.

Increased survival of skin flaps by scavengers of superoxide radical

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, L.; Privalle, C.T.; Serafin, D.

1987-08-01

Elevation of rat abdominal skin flaps, followed by ligation and division of the left inferior neurovascular pedicle, resulted in only a 40% survival of the area normally perfused by the ligated artery and vein. Superoxide dismutase (SOD) (EC1.15.1.1) administered v (20,000 U/kg) 30 min before flap elevation increased survival to 52%. SOD derivatized with polyethylene gycol, which increases circulating half-life, was more effective, increasing survival to 80%. This protective effect resulted from the catalytic activity of the derivatized enzyme because inactivation by treatment with H/sub 2/O/sub 2/ eliminated its effect on skin flap survival. An equimolar mixture of Desferal andmore » MnCl/sub 2/, which catalyzes the dismutation of O/sub 2//sup -/ in vitro, improved survival to 72%. Desferal-Fe/sup 3 +/, which lacks in vitro SOD activity, or Mn/sup 2 +/ alone did not affect the survival of skin flaps, but Desferal alone was nearly as effective as the Desferal-Mn/sup 2 +/ mixture. This effect of Desferal may result from acquisition of and subsequent removal of iron in vivo. These results support the view that the superoxide radical or a product derived from it plays a role in limiting the survival of island skin flaps.« less

[Aesthetic effect of wound repair with flaps].

PubMed

Tan, Qian; Zhou, Hong-Reng; Wang, Shu-Qin; Zheng, Dong-Feng; Xu, Peng; Wu, Jie; Ge, Hua-Qiang; Lin, Yue; Yan, Xin

2012-08-01

To investigate the aesthetic effect of wound repair with flaps. One thousand nine hundred and ninety-six patients with 2082 wounds hospitalized from January 2004 to December 2011. These wounds included 503 deep burn wounds, 268 pressure sores, 392 soft tissue defects caused by trauma, 479 soft tissue defects due to resection of skin cancer and mole removal, 314 soft tissue defects caused by scar excision, and 126 other wounds. Wound area ranged from 1.5 cm x 1.0 cm to 30.0 cm x 22.0 cm. Sliding flaps, expanded flaps, pedicle flaps, and free flaps were used to repair the wounds in accordance with the principle and timing of wound repair with flaps. Five flaps showed venous congestion within 48 hours post-operation, 2 flaps of them improved after local massage. One flap survived after local heparin wet packing and venous bloodletting. One flap survived after emergency surgical embolectomy and bridging with saphenous vein graft. One flap showed partial necrosis and healed after skin grafting. The other flaps survived well. One thousand three hundred and twenty-one patients were followed up for 3 months to 2 years, and flaps of them were satisfactory in shape, color, and elasticity, similar to that of normal skin. Some patients underwent scar revision later with good results. Application of suitable flaps in wound repair will result in quick wound healing, good function recovery, and satisfactory aesthetic effect.

Propeller Flap for Complex Distal Leg Reconstruction: A Versatile Alternative when Reverse Sural Artery Flap is Not Feasible.

PubMed

Ademola, Samuel A; Michael, Afieharo I; Oladeji, Femi J; Mbaya, Kefas M; Oyewole, O

2015-01-01

Reverse sural artery fasciocutaneous flap has become a workhorse for the reconstruction of distal leg soft tissue defects. When its use is not feasible, perforator-based propeller flap offers a better, easier, faster, and cheaper alternative to free flap. We present our experience with two men both aged 34 years who sustained Gustilo 3B injuries from gunshot. The donor area for reversed sural artery flap was involved in the injuries. They had early debridement, external fixation, and wound coverage with perforator-based propeller flaps. The donor sites were covered with skin graft. All flaps survived. There were minor wound edge ulcers due to the pressure of positioning that did not affect flap survival and the ulcers healed with conservative management. Perforator-based propeller flap is a versatile armamentarium for reconstruction of soft tissue defects of the distal leg in resource-constrained settings, especially when the donor area for a reverse flow sural flap artery is involved in the injury.

Comparison of gluteal fasciocutaneous rotational flaps and myocutaneous flaps for the treatment of sacral sores

PubMed Central

Ip, F. K.

2005-01-01

To compare the outcomes of gluteal fasciocutaneous rotational flaps and myocutaneous flaps in the treatment of sacral sores, together with a review of surgical complications in two matched cohorts. Thirty-eight patients (18 gluteal fasciocutaneous rotational flaps and 20 myocutaneous flaps) were reviewed retrospectively at a mean follow-up of 58 weeks. The rate of healing of the sore, the sore healing time, and the incidence of surgical complications, together with rate of recurrence, were obtained by chart review. Treatment groups were matched by patient characteristics, operative time and blood loss. The rate of healing of the sore, sore healing time and complication rate were comparable in the two groups but the rate of recurrence was lower to a statistically significant extent in myocutaneous flap patients. The authors suggest that both methods are comparable, good and safe in treating sacral sores; myocutaneous flaps are more durable. PMID:16333656

The myocutaneous trapezius flap revisited: a treatment algorithm for optimal surgical outcomes based on 43 flap reconstructions.

PubMed

Can, Anil; Orgill, Dennis P; Dietmar Ulrich, J O; Mureau, Marc A M

2014-12-01

Because the vascular anatomy of the trapezius flap is highly variable, choosing the most appropriate flap type and design is essential to optimize outcomes and minimize postoperative complications. The aim of this study was to develop a surgical treatment algorithm for trapezius flap transfers. The medical files of all consecutive patients with a myocutaneous trapezius flap reconstruction of the head, neck, and upper back area treated at three different university medical centers between July 2001 and November 2012 were reviewed. There were 43 consecutive flaps performed in 38 patients with a mean follow-up time of 15 months (range, 1-48 months). Eleven patients had a mentosternal burn scar contracture (12 flaps), 12 patients (13 flaps) presented with cancer, and 15 patients (18 flaps) were suffering from chronic wounds due to failed previous reconstruction (n = 6), osteoradionecrosis (n = 1), chronic infection (n = 3), bronchopleural fistula (n = 3), and pressure sores (n = 2). The mean defect size was 152 cm(2). Sixteen flaps were based on the superficial cervical artery (SCA; type 2), 16 were based on the dorsal scapular artery (DSA; type 3), one was based on the intercostal arteries (type 4), and 10 flaps were based on both the DSA and SCA. Recipient-site complications requiring reoperation occurred in 16.3%, including one total flap failure (2.6%). The trapezius myocutaneous flap is a valuable option to reconstruct various head and neck and upper back defects. Based on our data, a surgical treatment algorithm was developed in an attempt to reduce variation in care and improve clinical outcomes. Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Treatment of ischial pressure sores with both profunda femoris artery perforator flaps and muscle flaps.

PubMed

Kim, Chae Min; Yun, In Sik; Lee, Dong Won; Lew, Dae Hyun; Rah, Dong Kyun; Lee, Won Jai

2014-07-01

Reconstruction of ischial pressure sore defects is challenging due to extensive bursas and high recurrence rates. In this study, we simultaneously applied a muscle flap that covered the exposed ischium and large bursa with sufficient muscular volume and a profunda femoris artery perforator fasciocutaneous flap for the management of ischial pressure sores. We retrospectively analyzed data from 14 patients (16 ischial sores) whose ischial defects had been reconstructed using both a profunda femoris artery perforator flap and a muscle flap between January 2006 and February 2014. We compared patient characteristics, operative procedure, and clinical course. All flaps survived the entire follow-up period. Seven patients (50%) had a history of surgery at the site of the ischial pressure sore. The mean age of the patients included was 52.8 years (range, 18-85 years). The mean follow-up period was 27.9 months (range, 3-57 months). In two patients, a biceps femoris muscle flap was used, while a gracilis muscle flap was used in the remaining patients. In four cases (25%), wound dehiscence occurred, but healed without further complication after resuturing. Additionally, congestion occurred in one case (6%), but resolved with conservative treatment. Among 16 cases, there was only one (6%) recurrence at 34 months. The combination of a profunda femoris artery perforator fasciocutaneous flap and muscle flap for the treatment of ischial pressure sores provided pliability, adequate bulkiness and few long-term complications. Therefore, this may be used as an alternative treatment method for ischial pressure sores.

Treatment of Ischial Pressure Sores with Both Profunda Femoris Artery Perforator Flaps and Muscle Flaps

PubMed Central

Kim, Chae Min; Yun, In Sik; Lee, Dong Won; Lew, Dae Hyun; Rah, Dong Kyun

2014-01-01

Background Reconstruction of ischial pressure sore defects is challenging due to extensive bursas and high recurrence rates. In this study, we simultaneously applied a muscle flap that covered the exposed ischium and large bursa with sufficient muscular volume and a profunda femoris artery perforator fasciocutaneous flap for the management of ischial pressure sores. Methods We retrospectively analyzed data from 14 patients (16 ischial sores) whose ischial defects had been reconstructed using both a profunda femoris artery perforator flap and a muscle flap between January 2006 and February 2014. We compared patient characteristics, operative procedure, and clinical course. Results All flaps survived the entire follow-up period. Seven patients (50%) had a history of surgery at the site of the ischial pressure sore. The mean age of the patients included was 52.8 years (range, 18-85 years). The mean follow-up period was 27.9 months (range, 3-57 months). In two patients, a biceps femoris muscle flap was used, while a gracilis muscle flap was used in the remaining patients. In four cases (25%), wound dehiscence occurred, but healed without further complication after resuturing. Additionally, congestion occurred in one case (6%), but resolved with conservative treatment. Among 16 cases, there was only one (6%) recurrence at 34 months. Conclusions The combination of a profunda femoris artery perforator fasciocutaneous flap and muscle flap for the treatment of ischial pressure sores provided pliability, adequate bulkiness and few long-term complications. Therefore, this may be used as an alternative treatment method for ischial pressure sores. PMID:25075362

Gastrocnaemius-propeller extended miocutanous flap: a new chimaeric flap for soft tissue reconstruction of the knee.

PubMed

Innocenti, M; Cardin-Langlois, E; Menichini, G; Baldrighi, C

2014-02-01

Soft tissue defects involving the anterior aspect of the knee are a frequent finding in a number of pathological conditions. The aim of this article is to describe a new pedicled flap consisting of a conventional medial gastrocnaemius muscle flap associated with a propeller flap based on a perforator of the medial sural artery. Five males ranging in age between 26 and 72 years underwent a reconstruction of the soft tissue of the knee by means of the described procedure. Three patients sustained complex tissue loss subsequent to high-energy trauma; two losses were due to septic complications after elective knee surgery. Four flaps survived allowing adequate proximal tibial metaphysis and patella coverage. One patient underwent early above-the-knee amputation due to life-threatening septicaemia. The described chimaera flap consists of a medial gastrocnaemius flap with a skin paddle that is elevated on a perforator of the medial sural artery and then rotated according to the propeller flaps' principles. It provides effective coverage of large soft tissue defects of the knee. In the authors' experience, the propeller flap portion proved to be particularly useful to cover the patella, while the muscle flap was used to cover the proximal metaphysis of the tibia and fill the dead space if present. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Experimental validation of a true-scale morphing flap for large civil aircraft applications

NASA Astrophysics Data System (ADS)

Pecora, R.; Amoroso, F.; Arena, M.; Noviello, M. C.; Rea, F.

2017-04-01

Within the framework of the JTI-Clean Sky (CS) project, and during the first phase of the Low Noise Configuration Domain of the Green Regional Aircraft - Integrated Technological Demonstration (GRA-ITD, the preliminary design and technological demonstration of a novel wing flap architecture were addressed. Research activities were carried out to substantiate the feasibility of morphing concepts enabling flap camber variation in compliance with the demanding safety requirements applicable to the next generation green regional aircraft, 130- seats with open rotor configuration. The driving motivation for the investigation on such a technology was found in the opportunity to replace a conventional double slotted flap with a single slotted camber-morphing flap assuring similar high lift performances -in terms of maximum attainable lift coefficient and stall angle- while lowering emitted noise and system complexity. Studies and tests were limited to a portion of the flap element obtained by slicing the actual flap geometry with two cutting planes distant 0.8 meters along the wing span. Further activities were then addressed in order to increase the TRL of the validated architecture within the second phase of the CS-GRA. Relying upon the already assessed concept, an innovative and more advanced flap device was designed in order to enable two different morphing modes on the basis of the A/C flight condition / flap setting: Mode1, Overall camber morphing to enhance high-lift performances during take-off and landing (flap deployed); Mode2, Tab-like morphing mode. Upwards and downwards deflection of the flap tip during cruise (flap stowed) for load control at high speed. A true-scale segment of the outer wing flap (4 meters span with a mean chord of 0.9 meters) was selected as investigation domain for the new architecture in order to duly face the challenges posed by real wing installation. Advanced and innovative solutions for the adaptive structure, actuation and control

Energy extraction from a semi-passive flapping-foil turbine with active heave and passive pitch

NASA Astrophysics Data System (ADS)

Boudreau, Matthieu; Dumas, Guy; Gunther, Kevin; CFD Laboratory LMFN Team

2017-11-01

Due to the inherent complexity of the mechanisms needed to prescribe the heaving and the pitching motions of optimal flapping-foil turbines, several research groups are now investigating the potential of using unconstrained passive motions. The amplitude, the phase and the frequency of such free motions are thus the result of the interaction of the blade with the flow and its elastic supports, namely springs and dampers. In parallel with our current study on fully-passive flapping-foil turbines, we investigate in this work the possibility of using a semi-passive turbine. Unlike previous semi-passive turbines studied in the literature, we propose a turbine with a passive pitching motion and an active heaving motion constrained to be a sine wave with desired amplitude and frequency. As most of the energy extracted by flapping-foil turbines comes from the heaving motion, it is natural to connect an electric generator to this degree of freedom, thereby allowing one to constrain this motion. It is found that large-amplitude pitching motions leading to a considerable energy extraction can arise under different circumstances and mechanisms, either forced by the heaving motion or driven by an instability of the pitching motion itself. The authors gratefully acknowledge the support from the Natural Sciences and Engineering Research Council of Canada (NSERC), the Tyler Lewis Clean Energy Research Foundation, Calcul Québec and Compute Canada.

Free Boomerang-shaped Extended Rectus Abdominis Myocutaneous flap: The longest possible skin/myocutaneous free flap for soft tissue reconstruction of extremities.

PubMed

Koul, Ashok R; Nahar, Sushil; Prabhu, Jagdish; Kale, Subhash M; Kumar, Praveen H P

2011-09-01

A soft tissue defect requiring flap cover which is longer than that provided by the conventional "long" free flaps like latissimus dorsi (LD) and anterolateral thigh (ALT) flap is a challenging problem. Often, in such a situation, a combination of flaps is required. Over the last 3 years, we have managed nine such defects successfully with a free "Boomerang-shaped" Extended Rectus Abdominis Myocutaneous (BERAM) flap. This flap is the slightly modified and "free" version of a similar flap described by Ian Taylor in 1983. This is a retrospective study of patients who underwent free BERAM flap reconstruction of soft tissue defects of extremity over the last 3 years. We also did a clinical study on 30 volunteers to compare the length of flap available using our design of BERAM flap with the maximum available flap length of LD and ALT flaps, using standard markings. Our clinical experience of nine cases combined with the results of our clinical study has confirmed that our design of BERAM flap consistently provides a flap length which is 32.6% longer than the standard LD flap and 42.2% longer than the standard ALT flap in adults. The difference is even more marked in children. The BERAM flap is consistently reliable as long as the distal end is not extended beyond the mid-axillary line. BERAM flap is simple in design, easy to harvest, reliable and provides the longest possible free skin/myocutaneous flap in the body. It is a useful new alternative for covering long soft tissue defects in the limbs.

Flap Conformations in HIV-1 Protease are Altered by Mutations

NASA Astrophysics Data System (ADS)

Fanucci, Gail; Blackburn, Mandy; Veloro, Angelo; Galiano, Luis; Fangu, Ding; Simmerling, Carlos

2009-03-01

HIV-1 protease (PR) is an enzyme that is a major drug target in the treatment of AIDS. Although the structure and function of HIV-1 PR have been studied for over 20 years, questions remain regarding the conformations and dynamics of the β-hairpin turns (flaps) that cover the active site cavity. Distance measurements with pulsed EPR spectroscopy of spin labeled constructs of HIV-1 PR have been used to characterize the flap conformations in the apo and inhibitor bound states. From the most probably distances and the breadth of the distance distribution profiles from analysis of the EPR data, insights regarding the flap conformations and flexibility are gained. The EPR results clearly show how drug pressure selected mutations alter the average conformation of the flaps and the degree of opening of the flaps. Molecular dynamics simulations successfully regenerate the experimentally determined distance distribution profiles, and more importantly, provide structural models for full interpretation of the EPR results. By combining experiment and theory to understand the role that altered flap flexibility/conformations play in the mechanism of drug resistance, key insights are gained toward the rational development of new inhibitors of this important enzyme.

Pedicled Extranasal Flaps in Skull Base Reconstruction

PubMed Central

Kim, Grace G.; Hang, Anna X.; Mitchell, Candace; Zanation, Adam M.

2013-01-01

Cerebrospinal fluid (CSF) leaks most commonly arise during or after skull base surgery, although they occasionally present spontaneously. Recent advances in the repair of CSF leaks have enabled endoscopic endonasal surgery to become the preferred option for management of skull base pathology. Small defects (<1cm) can be repaired by multilayered free grafts. For large defects (>3cm), pedicled vascular flaps are the repair method of choice, resulting in much lower rates of postoperative CSF leaks. The pedicled nasoseptal flap (NSF) constitutes the primary reconstructive option for the vast majority of skull base defects. It has a large area of potential coverage and high rates of success. However, preoperative planning is required to avoid sacrificing the NSF during resection. In cases where the NSF is unavailable, often due to tumor involvement of the septum or previous resection removing or compromising the flap, other flaps may be considered. These flaps include intranasal options—inferior turbinate (IT) or middle turbinate (MT) flaps—as well as regional pedicled flaps: pericranial flap (PCF), temporoparietal fascial flap (TPFF), or palatal flap (PF). More recently, novel alternatives such as the pedicled facial buccinator flap (FAB) and the pedicled occipital galeopericranial flap (OGP) have been added to the arsenal of options for skull base reconstruction. Characteristics of and appropriate uses for each flap are described. PMID:23257554

The radix nasi island flap: a versatile musculocutaneous flap for defects of the eyelids, nose, and malar region.

PubMed

Seyhan, Tamer

2009-03-01

A versatile musculocutan flap from the radix nasi region, the radix nasi island flap, is described. The flap has an axial blood supply derived from the dorsal nasal branch of the ophthalmic artery which is anastomosed to the terminal branch of the facial artery. The flap includes the skin, subcutaneous tissue, and procerus muscle. Ten patients, aged 50 to 86 years, have been reconstructed with this flap for defects in the nose (in 4 cases), midface (in 4 cases) and lower eyelids (in 2 cases). The mean flap size was 17 x 23 mm (range: 15 x 20 to 20 x 27 mm). All flaps fully survived. Additional complications and morbidity were not observed. The donor sites were closed a primarily closure in all cases. Follow-up ranged from 3 to 12 months (mean: 8.2 months). The radix nasi flap is a safe flap, has minimal donor site morbidity, and is especially suited for nasal and midface reconstruction in terms of attaining a suitable color and thickness.

Free Boomerang-shaped Extended Rectus Abdominis Myocutaneous flap: The longest possible skin/myocutaneous free flap for soft tissue reconstruction of extremities

PubMed Central

Koul, Ashok R.; Nahar, Sushil; Prabhu, Jagdish; Kale, Subhash M.; Kumar, Praveen H. P.

2011-01-01

Background: A soft tissue defect requiring flap cover which is longer than that provided by the conventional “long” free flaps like latissimus dorsi (LD) and anterolateral thigh (ALT) flap is a challenging problem. Often, in such a situation, a combination of flaps is required. Over the last 3 years, we have managed nine such defects successfully with a free “Boomerang-shaped” Extended Rectus Abdominis Myocutaneous (BERAM) flap. This flap is the slightly modified and “free” version of a similar flap described by Ian Taylor in 1983. Materials and Methods: This is a retrospective study of patients who underwent free BERAM flap reconstruction of soft tissue defects of extremity over the last 3 years. We also did a clinical study on 30 volunteers to compare the length of flap available using our design of BERAM flap with the maximum available flap length of LD and ALT flaps, using standard markings. Results: Our clinical experience of nine cases combined with the results of our clinical study has confirmed that our design of BERAM flap consistently provides a flap length which is 32.6% longer than the standard LD flap and 42.2% longer than the standard ALT flap in adults. The difference is even more marked in children. The BERAM flap is consistently reliable as long as the distal end is not extended beyond the mid-axillary line. Conclusion: BERAM flap is simple in design, easy to harvest, reliable and provides the longest possible free skin/myocutaneous flap in the body. It is a useful new alternative for covering long soft tissue defects in the limbs. PMID:22279271

Cost-effectiveness of monitoring free flaps.

PubMed

Subramaniam, Shiva; Sharp, David; Jardim, Christopher; Batstone, Martin D

2016-06-01

Methods of free flap monitoring have become more sophisticated and expensive. This study aims to determine the cost of free flap monitoring and examine its cost effectiveness. We examined a group of patients who had had free flaps to the head and neck over a two-year period, and combined these results with costs obtained from business managers and staff. There were 132 free flaps with a success rate of 99%. The cost of monitoring was Aus $193/flap. Clinical monitoring during this time period cost Aus$25 476 and did not lead to the salvage of any free flaps. Cost equivalence is reached between monitoring and not monitoring only at a failure rate of 15.8%. This is to our knowledge the first study to calculate the cost of clinical monitoring of free flaps, and to examine its cost-effectiveness. Copyright © 2016 The British Association of Oral and Maxillofacial Surgeons. All rights reserved.

Rotation Flaps-Principles and Locations.

PubMed

LoPiccolo, Matteo C

2015-10-01

The rotation flap is a classic method of tissue rearrangement. It is a simple yet effective tool for recruiting tissue from areas of laxity and redirecting vectors of tension to reconstruct wounds not amenable to primary closure. This article presents the basic design principles and specific applications of the rotation flap in dermatologic surgery. A Medline search of articles describing rotation flaps published prior to April 1, 2015 was performed, and several prominent texts in dermatologic surgery were reviewed. Information gathered from the above sources is combined with the clinical experience of the author and editors to present surgeons with a guide for planning and executing various rotation flaps. Mastering the technique of the rotation flap will allow a surgeon to repair a wide variety of cutaneous defects.

Lower Extremity Free Flaps for Breast Reconstruction.

PubMed

Dayan, Joseph H; Allen, Robert J

2017-11-01

Thigh-based flaps are typically a secondary option for breast reconstruction because of concerns regarding limited tissue volume and donor-site morbidity. In recent years, there have been a number of new techniques and insights that have resulted in greater flexibility and improved outcomes. This article reviews lessons learned from a large collective experience using the following 4 flaps: transverse upper gracilis also known as transverse myocutaneous gracilis, diagonal upper gracilis, profunda artery perforator, and lateral thigh perforator flaps. Flap selection considerations include the patient's fat distribution and skin laxity, perforator anatomy, and scar location. Pearls to minimize donor-site morbidity include avoiding major lymphatic collectors in the femoral triangle and along the greater saphenous vein and respecting the limits of flap dimension to reduce wound healing complications and distal ischemia. Limited flap volume may be addressed with stacking another flap from the contralateral thigh or primary fat grafting as opposed to overaggressive flap harvest from a single thigh. A detailed review of the benefits and disadvantages of each flap and strategies to improve results is discussed. With careful planning and selection, thigh-based flaps can provide a reliable option patients desiring autologous breast reconstruction.

Bilobed flap in sole surgery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanchez-Conejo-Mir, J.; Bueno Montes, J.; Moreno Gimenez, J.C.

1985-09-01

The bilobed flap is a simple reconstructive technique principally used to correct substantial defects in the facial region. The authors present their experience with this local flap in the difficult plantar area, with excellent short-term functional results. They describe the special characteristics of the bilobed flap in this zone, and comment on its indications and possible complications.

Optimization design and dynamic analysis on the drive mechanisms of flapping-wing air vehicles based on flapping trajectories

NASA Astrophysics Data System (ADS)

Xie, Lingwang; Zhang, Xingwei; Luo, Pan; Huang, Panpan

2017-10-01

The optimization designs and dynamic analysis on the driving mechanism of flapping-wing air vehicles on base of flapping trajectory patterns is carried out in this study. Three different driving mechanisms which are spatial double crank-rocker, plane five-bar and gear-double slider, are systematically optimized and analysed by using the Mat lab and Adams software. After a series debugging on the parameter, the comparatively ideal flapping trajectories are obtained by the simulation of Adams. Present results indicate that different drive mechanisms output different flapping trajectories and have their unique characteristic. The spatial double crank-rocker mechanism can only output the arc flapping trajectory and it has the advantages of small volume, high flexibility and efficient space utilization. Both planar five-bar mechanism and gear-double slider mechanism can output the oval, figure of eight and double eight flapping trajectories. Nevertheless, the gear-double slider mechanism has the advantage of convenient parameter setting and better performance in output double eight flapping trajectory. This study can provide theoretical basis and helpful reference for the design of the drive mechanisms of flapping-wing air vehicles with different output flapping trajectories.

Forward flight of swallowtail butterfly with simple flapping motion.

PubMed

Tanaka, Hiroto; Shimoyama, Isao

2010-06-01

Unlike other flying insects, the wing motion of swallowtail butterflies is basically limited to flapping because their fore wings partly overlap their hind wings, structurally restricting the feathering needed for active control of aerodynamic force. Hence, it can be hypothesized that the flight of swallowtail butterflies is realized with simple flapping, requiring little feedback control of the feathering angle. To verify this hypothesis, we fabricated an artificial butterfly mimicking the wing motion and wing shape of a swallowtail butterfly and analyzed its flights using images taken with a high-speed video camera. The results demonstrated that stable forward flight could be realized without active feathering or feedback control of the wing motion. During the flights, the artificial butterfly's body moved up and down passively in synchronization with the flapping, and the artificial butterfly followed an undulating flight trajectory like an actual swallowtail butterfly. Without feedback control of the wing motion, the body movement is directly affected by change of aerodynamic force due to the wing deformation; the degree of deformation was determined by the wing venation. Unlike a veinless wing, a mimic wing with veins generated a much higher lift coefficient during the flapping flight than in a steady flow due to the large body motion.

Skin flaps and grafts - self-care

MedlinePlus

... Free flap - self-care; Skin autografting - self-care; Pressure ulcer skin flap self-care; Burns skin flap self- ... skin infection Surgery for skin cancer Venous ulcers , pressure ulcers , or diabetic ulcers that DO NOT heal After ...

Active control system for a rotor blade trailing-edge flap

NASA Astrophysics Data System (ADS)

Duvernier, Marc; Reithler, Livier; Guerrero, Jean Y.; Rossi, Rinaldo A.

2000-06-01

Reducing the external noise is becoming a major issue for helicopter manufacturers. The idea beyond this goal is to reduce or even avoid the blade vortex interaction (BVI), especially during descent and flights over inhabited areas. This can be achieved by changing locally the lift of the blade. Several strategies to reach this goal are under investigation at EUROCOPTER such as the control of the local incidence of the blade by a direct lift flap. AEROSPATIALE MATRA Corporate Research Centre and AEROSPATIALE MATRA MISSILES proposed an actuator system able to answer EUROCOPTER's needs for moving a direct lift flap. The present paper describes the definition, manufacturing and testing of this new actuator system. This actuator is based on an electromagnetic patented actuation system developed by AEROSPATIALE MATRA MISSILES for missile and aeronautic applications. The particularity of this actuator is its ability to produce the desired force on its whole range of stroke. The flap is designed to be fitted on a DAUPHIN type blade produced by EUROCOPTER and the actuator system was designed to fit the room available within the blade and to produce the right amount of stroke and force within the required frequency range. Other constraints such as centrifugal loading were also taken into account. This paper describes briefly the specifications and the major characteristics of the actuating system and presents some results of its behavior on a representative composite test-bed manufactured by EUROCOPTER when subjected to realistic mechanical loads.

A new mucosal propeller flap (deep lingual artery axial propeller): the renaissance of lingual flaps.

PubMed

Cordova, Adriana; Toia, Francesca; D'Arpa, Salvatore; Giunta, Gabriele; Moschella, Francesco

2015-03-01

Lingual flaps provide ideal mucosal coverage for intraoral defects but traditionally require two surgical stages. The authors present an axial mucosal propeller flap for single-stage intraoral reconstruction. The flap includes the mucosa of the lateral side of the tongue, islanded on the deep lingual vessels. Between 2011 and 2013, 23 patients underwent intraoral mucosal reconstruction with a deep lingual artery axial propeller flap after cancer resection in the cheek (n = 16), floor of the mouth (n = 2), retromolar trigone (n = 2), hard palate (n = 2), and soft palate (n = 1). Mean defect size was 19.5 cm. Preoperative and postoperative intraoral function was evaluated with the Functional Intraoral Glasgow Scale. The authors always achieved one-stage reconstruction with primary donor-site closure. The only complications were an infection treated conservatively and a late oronasal fistula caused by radiotherapy. All patients resumed an oral diet after 1 week and none required surgical revision. Mean 12-month postoperative Functional Intraoral Glasgow Scale score was better than the preoperative score (13.5 versus 12.8). The deep lingual artery axial propeller flap combines the advantages of the traditional lingual flap (i.e., reliable axial vascularization and like-with-like reconstruction) with those of a propeller flap (i.e., one-stage transfer of like tissue and extreme mobility) and has wider indications than a conventional lingual flap. The technique is fast and has low morbidity and good functional results, and the authors recommend it as a first-choice technique to reconstruct moderate to large intraoral defects. Therapeutic, IV.

Development of a morphing flap using shape memory alloy actuators: the aerodynamic characteristics of a morphing flap

NASA Astrophysics Data System (ADS)

Ko, Seung-Hee; Bae, Jae-Sung; Rho, Jin-Ho

2014-07-01

The discontinuous contour of a wing with conventional flaps diminishes the aerodynamic performance of an aircraft. A wing with a continuous contour does not experience extreme flow stream fluctuations during flight, and consequently has good aerodynamic characteristics. In this study, a morphing flap using shape memory alloy actuators is proposed, designed and fabricated, and its aerodynamic characteristics are investigated using aerodynamic analyses and wind tunnel tests. The ribs of the morphing flap are designed and fabricated with multiple elements joined together in a way that allows relative rotations of adjacent elements and forms a smooth contour of the morphing flap. The aerodynamic analyses of this multiple-element morphing-flap wing are performed using XFLR pro; its aerodynamic performance is compared with that of a mechanical-flap wing, and is measured through wind-tunnel tests.

Blade-Mounted Flap Control for BVI Noise Reduction Proof-of-Concept Test

NASA Technical Reports Server (NTRS)

Dawson, Seth; Hassan, Ahmed; Straub, Friedrich; Tadghighi, Hormoz

1995-01-01

This report describes a wind tunnel test of the McDonnell Douglas Helicopter Systems (MDHS) Active Flap Model Rotor at the NASA Langley 14- by 22-Foot Subsonic Tunnel. The test demonstrated that BVI noise reductions and vibration reductions were possible with the use of an active flap. Aerodynamic results supported the acoustic data trends, showing a reduction in the strength of the tip vortex with the deflection of the flap. Acoustic results showed that the flap deployment, depending on the peak deflection angle and azimuthal shift in its deployment schedule, can produce BVI noise reductions as much as 6 dB on the advancing and retreating sides. The noise reduction was accompanied by an increase in low frequency harmonic noise and high frequency broadband noise. A brief assessment of the effect of the flap on vibration showed that significant reductions were possible. The greatest vibration reductions (as much as 76%) were found in the four per rev pitching moment at the hub. Performance improvement cam results were inconclusive, as the improvements were predicted to be smaller than the resolution of the rotor balance.

Aerodynamic characteristics of a wing with Fowler flaps including flap loads, downwash, and calculated effect on take-off

NASA Technical Reports Server (NTRS)

Platt, Robert C

1936-01-01

This report presents the results of wind tunnel tests of a wing in combination with each of three sizes of Fowler flap. The purpose of the investigation was to determine the aerodynamic characteristics as affected by flap chord and position, the air loads on the flaps, and the effect of flaps on the downwash.

Sulfolobus chromatin proteins modulate strand displacement by DNA polymerase B1

PubMed Central

Sun, Fei; Huang, Li

2013-01-01

Strand displacement by a DNA polymerase serves a key role in Okazaki fragment maturation, which involves displacement of the RNA primer of the preexisting Okazaki fragment into a flap structure, and subsequent flap removal and fragment ligation. We investigated the role of Sulfolobus chromatin proteins Sso7d and Cren7 in strand displacement by DNA polymerase B1 (PolB1) from the hyperthermophilic archaeon Sulfolobus solfataricus. PolB1 showed a robust strand displacement activity and was capable of synthesizing thousands of nucleotides on a DNA-primed 72-nt single-stranded circular DNA template. This activity was inhibited by both Sso7d and Cren7, which limited the flap length to 3–4 nt at saturating concentrations. However, neither protein inhibited RNA displacement on an RNA-primed single-stranded DNA minicircle by PolB1. Strand displacement remained sensitive to modulation by the chromatin proteins when PolB1 was in association with proliferating cell nuclear antigen. Inhibition of DNA instead of RNA strand displacement by the chromatin proteins is consistent with the finding that double-stranded DNA was more efficiently bound and stabilized than an RNA:DNA duplex by these proteins. Our results suggest that Sulfolobus chromatin proteins modulate strand displacement by PolB1, permitting efficient removal of the RNA primer while inhibiting excessive displacement of the newly synthesized DNA strand during Okazaki fragment maturation. PMID:23821667

Small Molecule Regulation of Protein Conformation by Binding in the Flap of HIV Protease

PubMed Central

Tiefenbrunn, Theresa; Forli, Stefano; Baksh, Michael M.; Chang, Max W.; Happer, Meaghan; Lin, Ying-Chuan; Perryman, Alexander L.; Rhee, Jin-Kyu; Torbett, Bruce E.; Olson, Arthur J.; Elder, John H.; Finn, M. G.; Stout, C. David

2013-01-01

The fragment indole-6-carboxylic acid (1F1), previously identified as a flap site binder in a fragment-based screen against HIV protease (PR), has been co-crystallized with pepstatin-inhibited PR and with apo-PR. Another fragment, 3-indolepropionic acid (1F1-N), predicted by AutoDock calculations and confirmed in a novel ‘inhibition of nucleation’ crystallization assay, exploits the same interactions in the flap site in two crystal structures. Both 1F1 and 1F1-N bind to the closed form of apo-PR and to pepstatin:PR. In solution, 1F1 and 1F1-N raise the Tm of apo-PR by 3.5–5 °C as assayed by differential scanning fluorimetry (DSF), and show equivalent low-micromolar binding constants to both apo-PR and pepstatin:PR, assayed by backscattering interferometry (BSI). The observed signal intensities in BSI are greater for each fragment upon binding to apo-PR than to pepstatin-bound PR, consistent with greater conformational change in the former binding event. Together, these data indicate that fragment binding in the flap site favors a closed conformation of HIV PR. PMID:23540839

Perforator Peroneal Artery Flap for Tongue Reconstruction.

PubMed

Chauhan, Shubhra; Chavre, Sachin; Chandrashekar, Naveen Hedne; B S, Naveen

2017-03-01

Reconstruction has evolved long way from primary closure to flaps. As time evolved, better understanding of vascularity of flap has led to the development of innovative reconstructive techniques. These flaps can be raised from various parts of the body for reconstruction and have shown least donor site morbidity. We use one such peroneal artery perforator flap for tongue reconstruction with advantage of thin pliable flap, minimal donor site morbidity and hidden scar. Our patient 57yrs old lady underwent wide local excision with selective neck dissection. Perforators are marked about 10 and 15 cm inferiorly from the fibular head using hand held Doppler. Leg is positioned in such a way to give better exposure during dissection of the flap and flap is harvested under a tourniquet with pressure kept 350 mm Hg. The perforator is kept at the eccentric location, so as to gain length of the pedicle. Skin incison is placed over the peroneal muscle and deepened unto the deep facia, then the dissection is continued over the muscle and the perforator arising from the lateral septum. The proximal perforator about 10 cm from the fibular head is a constant perforator and bigger one, which is traced up to the peroneal vessel. We could get a 6 cm of pedicle length. Finally the flap is islanded on this perforator and the pedicle is ligated and flap harvested. Anastamosis was done to the ipsilateral side to facial vessels. The donor site is closed primarily and in the upper half one can harvest 5 cm width flap without requiring a skin graft along with a length of 8 to 12 cm. Various local and free flap has been used for reconstruction of partial tongue defects with its obvious donor site problems, like less pliable skin and not so adequate tissue from local flaps and sacrificing a important artery as in radial forearm flap serves as the work horse in reconstruction of partial tongue defects, Concept of super microsurgery was popularized by Japanese in 1980s and the concept of

Lower Extremity Reconstruction with Free Gracilis Flaps

PubMed Central

Nicoson, Michael C; Parikh, Rajiv P; Tung, Thomas H

2017-01-01

Background There have been significant advancements in lower extremity reconstruction over the last several decades, and the plastic surgeon’s armamentarium has grown to include free muscle and fasciocutaneous flaps along with local perforator and propeller flaps. While we have found a use for a variety of techniques for lower extremity reconstruction, the free gracilis has been our workhorse flap due to the ease of harvest, reliability, and low donor site morbidity. Methods This is a retrospective review of a single surgeon’s series of free gracilis flaps utilized for lower extremity reconstruction. Demographic information, comorbidities, outcomes and secondary procedures were analyzed. Results We identified 24 free gracilis flaps. The duration from injury to free flap coverage was 7 days or less in 6 patients, 8–30 days in 11 patients, 31–90 days in 4 patients, and > 90 days in 3 patients. There were 22 (92%) successful flaps and an overall limb salvage rate of 92%. There was one partial flap loss. Two flaps underwent incision and drainage in the operating room for infection. Two patients developed donor site hematomas. Four patients underwent secondary procedures for contouring. Our subset of pediatric patients had 100% flap survival and no secondary procedures at a mean 30 month follow up. Conclusions This study demonstrates the utility of the free gracilis flap in reconstruction of small to medium sized defects of the lower extremity. This flap has a high success rate and low donor site morbidity. Atrophy of the denervated muscle over time allows for good shoe fit, often obviating the need for secondary contouring procedures. PMID:28024305

Reconstruction of a traumatic plantar foot defect with a novel free flap: The medial triceps brachii free flap.

PubMed

Leclère, Franck Marie; Casoli, Vincent

2015-01-01

Lower extremity defects may account for 14.6% of the approximately 117 million visits to emergency departments in the U. S. in 2007. In this article, we present a reconstruction of a traumatic plantar foot defect with a medial triceps brachii (MTB) free flap. A 53-year-old man sustained an accidental gunshot wound to the right foot. The patient was admitted after the failure of a sural flap procedure performed in another hospital. He presented with a soft-tissue defect with calcaneal exposition and osteomyelitis. The defect was reconstructed with a MTB free flap anastomosed to his dorsalis pedis vessels. Flap raising time was 52 min. There were no intraoperative complications. The total flap surface was 38.5 cm². The pedicle length was 3 cm. The diameters of the artery and vein of the flap pedicle were 1.1 mm and 1.4 mm, respectively. Ischemia time was 28 min. His donor site healed uneventfully without any morbidity, and the scar was well concealed. The flaps survived and there was no partial flap necrosis. A split-thickness skin graft was performed 12 days postoperatively. Two months later, he had a completely healed wound with no contour abnormality. The total follow-up was 24 months. The patient was able to walk normally. MTB free flap appears to be an excellent option for plantar foot defects in patients with preserved vascularization of the foot. Due to the anatomical shape of the flap, the position of its pedicle, and the moldability of the muscle, we predict that the use of the MTB free flap will grow and develop rapidly for reconstruction of ankle and foot defects.

A novel five-lipoxygenase activity protein inhibitor labeled with carbon-14 and deuterium.

PubMed

Latli, Bachir; Hrapchak, Matt; Gao, Joe J; Busacca, Carl A; Senanayake, Chris H

2015-07-01

2-[4-(3-{(1R)-1-[4-(2-Aminopyrimidin-5-yl)phenyl]-1-cyclopropylethyl}-1,2,4-oxadiazol-5-yl)-1H-pyrazol-1-yl]-N,N-dimethylacetamide (1), is a novel and selective five-lipoxygenase activity protein (FLAP) inhibitor with excellent pharmacokinetics properties. The availability of a key chiral intermediate allowed the synthesis of [(14) C]-(1) in six radiochemical steps and in 47% overall radiochemical yield with a specific activity of 51 mCi/mmol using carbon-14 zinc cyanide. 2-Chloro-N,N-dimethyl-(2)H6-acetamide was prepared and condensed with a penultimate intermediate to give [(2)H6]-(1) in very high yield and in more than 99% isotopic enrichment. Copyright © 2015 John Wiley & Sons, Ltd.

Tensor fascia lata flap versus tensor fascia lata perforator-based island flap for the coverage of extensive trochanteric pressure sores.

PubMed

Kim, Youn Hwan; Kim, Sang Wha; Kim, Jeong Tae; Kim, Chang Yeon

2013-06-01

Tensor fascia lata (TFL) musculocutaneous flaps often require a donor site graft when harvesting a large flap. However, a major drawback is that it also sacrifices the muscle. To overcome this disadvantage, we designed a TFL perforator-based island flap that was harvested from a site near the defect and involved transposition within 90 degrees without full isolation of the pedicles. We performed procedures on 17 musculocutaneous flaps and 23 perforator-based island flaps, and compared the outcomes of these surgeries. The overall complication rate was 27.5% (11 regions). There were 7 complications related to the musculocutaneous flaps and 4 complications related to the perforator flaps. Although there were no statistical differences between those groups, lower complication rates were associated with procedures involving perforator flaps. The TFL perforator procedure is a simple and fast operation that avoids sacrificing muscle. This decreases complication rates compared to true perforator flap techniques that require dissection around the perforator or pedicle.

Evaluation of the cranial rectus abdominus muscle pedicle flap as a blood supply for the caudal superficial epigastric skin flap in dogs.

PubMed

Degner, D A; Walshaw, R; Arnoczky, S P; Smith, R J; Patterson, J S; Degner, L A; Hamaide, A; Rosenstein, D

1996-01-01

This study evaluates the cranial rectus abdominus muscle pedicle flap as the sole blood supply for the caudal superficial epigastric skin flap. This flap was composed of a cranially based rectus abdominus muscle pedicle flap that was attached to the caudal superficial epigastric island skin flap (including mammary glands 2 to 5) via the pudendoepigastric trunk. Selective angiography of the cranial epigastric artery in eight cadaver dogs proved that the arterial vasculature in the cranial rectus abdominus was contiguous with that in the caudal superficial epigastric skin flap. In the live dog study, three of six of the flaps failed because of venous insufficiency. Necrosis of mammary gland 2 occurred in two of six flaps. One of six flaps survived with the exception of the cranial most aspect of mammary gland 2. Angiography of the cranial epigastric artery proved that arterial blood supply to these flaps was intact. Histological evaluation of the failed flaps showed full-thickness necrosis of the skin and subcutaneous tissues, the presence of severe congestion, and venous thrombosis. Retrograde venous blood flow through the flap was inconsistent, and hence resulted in failure of this myocutaneous flap. Use of this flap for clinical wound reconstruction cannot be recommended.

Use of Adipose-Derived Mesenchymal Stem Cells to Accelerate Neovascularization in Interpolation Flaps.

PubMed

Izmirli, Hakki Hayrettin; Alagoz, Murat Sahin; Gercek, Huseyin; Eren, Guler Gamze; Yucel, Ergin; Subasi, Cansu; Isgoren, Serkan; Muezzinoglu, Bahar; Karaoz, Erdal

2016-01-01

Interpolation flaps are commonly used in plastic surgery to cover wide and deep defects. The need to, wait for 2 to 3 weeks until the division of the pedicle still, however, poses a serious challenge, not only extending treatment and hospital stay, but also increasing hospital expenses. To solve this problem, we have aimed to use the angiogenic potential of stem cells to selectively accelerate neovascularization with a view to increasing the viability of interpolation flaps and achieving early pedicle removal. A total of 32 rats were allocated to 2 groups as control (N = 16) and experiment (N = 16). The cranial flaps 6 × 5 cm in size located on the back of the rats were raised. Then, a total suspension containing 3 × 10(6) adipose-derived mesenchymal stem cells (ADSC) tagged with a green fluorescent protein (GFP) was injected diffusely into the distal part of the flap, receiving bed, and wound edges. In the control group, only a medium solution was injected into the same sites. After covering the 3 × 5 cm region in the proximal part of the area where the flap was removed, the distal part of the flap was adapted to the uncovered distal area. The pedicles of 4 rats in each group were divided on postoperative days 5, 8, 11, and 14. The areas were photographed 7 days after the pedicles were released. The photographs were processed using Adobe Acrobat 9 Pro software (San Jose, CA) to measure the flap survival area in millimeters and to compare groups. Seven days after the flap pedicle was divided, the rats were injected with 250 mCi Tc-99 mm (methoxy-isobutyl-isonitrie) from the penile vein, and scintigraphic images were obtained. The images obtained from each group were subjected to a numerical evaluation, which was then used in the comparison between groups. The flaps were then examined by histology to numerically compare the number of newly formed vessels. Neovascularization was also assessed by microangiography. In addition, radiographic images were obtained by

14 CFR 23.697 - Wing flap controls.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Wing flap controls. 23.697 Section 23.697... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.697 Wing flap controls. (a) Each wing flap control must be designed so that, when the flap...

14 CFR 23.697 - Wing flap controls.

Code of Federal Regulations, 2011 CFR

2011-01-01

... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.697 Wing flap controls. (a) Each wing flap control must be designed so that, when the flap... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Wing flap controls. 23.697 Section 23.697...

14 CFR 23.697 - Wing flap controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.697 Wing flap controls. (a) Each wing flap control must be designed so that, when the flap... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Wing flap controls. 23.697 Section 23.697...

14 CFR 23.697 - Wing flap controls.

Code of Federal Regulations, 2014 CFR

2014-01-01

... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.697 Wing flap controls. (a) Each wing flap control must be designed so that, when the flap... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Wing flap controls. 23.697 Section 23.697...

14 CFR 23.697 - Wing flap controls.

Code of Federal Regulations, 2010 CFR

2010-01-01

... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.697 Wing flap controls. (a) Each wing flap control must be designed so that, when the flap... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Wing flap controls. 23.697 Section 23.697...

Propeller thoracodorsal artery perforator flap for breast reconstruction.

PubMed

Angrigiani, Claudio; Rancati, Alberto; Escudero, Ezequiel; Artero, Guillermo; Gercovich, Gustavo; Deza, Ernesto Gil

2014-08-01

The thoracodorsal artery perforator (TDAP) flap has been described for breast reconstruction. This flap requires intramuscular dissection of the pedicle. A modification of the conventional TDAP surgical technique for breast reconstruction is described, utilizing instead a propeller TDAP flap. The authors present their clinical experience with the propeller TDAP flap in breast reconstruction alone or in combination with expanders or permanent implants. From January 2009 to February 2013, sixteen patients had breast reconstruction utilizing a propeller TDAP flap. Retrospective analysis of patient characteristics, clinical indications, procedure and outcomes were performed. The follow-up period ranged from 4 to 48 months. Sixteen patients had breast reconstruction using a TDAP flap with or without simultaneous insertion of an expander or implant. All flaps survived, while two cases required minimal resection due to distal flap necrosis, healing by second intention. There were not donor-site seromas, while minimal wound dehiscence was detected in two cases. The propeller TDAP flap appears to be safe and effective for breast reconstruction, resulting in minimal donor site morbidity. The use of this propeller flap emerges as a true alternative to the traditional TDAP flap.

Free flap reconstruction for diabetic foot limb salvage.

PubMed

Sato, Tomoya; Yana, Yuichiro; Ichioka, Shigeru

2017-12-01

Although free flap is gaining popularity for the reconstruction of diabetic foot ulcers, it is unclear whether free flap reconstruction increases the chances of postoperative independent ambulation. The aim of this study is to evaluate the relationship between free flap success and postoperative ambulation. This study reviewed 23 cases of free flap reconstruction for diabetic foot ulcers between January 2007 and March 2014. Free rectus abdominis, latissimus dorsi, and anterolateral thigh flaps were used in ten, eight, and five patients, respectively. A comparison was made between free flap success and postoperative independent ambulation using Fisher's exact test. Two patients developed congestive heart failure with fatal consequences within 14 days postoperatively, resulting in an in-hospital mortality rate of 8.7%. Five patients lost their flaps (21.7%). Of the 16 patients who had flap success, 12 achieved independent ambulation. Five patients with flap loss did not achieve independent ambulation, except one patient who underwent secondary flap reconstruction using a distally based sural flap. Fisher's exact test revealed that independent ambulation was associated with free flap success (p = 0.047). The present study indicates that free flap reconstruction may increase the possibility of independent ambulation for patients with extensive tissue defects due to diabetic ulcers. Intermediate limb salvage rates and independent ambulation rates were favourable in patients with successful reconstruction. The use of foot orthoses and a team approach with pedorthists were effective to prevent recurrence.

Single-stage interpolation flaps in facial reconstruction.

PubMed

Hollmig, S Tyler; Leach, Brian C; Cook, Joel

2014-09-01

Relatively deep and complex surgical defects, particularly when adjacent to or involving free margins, present significant reconstructive challenges. When the use of local flaps is precluded by native anatomic restrictions, interpolation flaps may be modified to address these difficult wounds in a single operative session. To provide a framework to approach difficult soft tissue defects arising near or involving free margins and to demonstrate appropriate design and execution of single-stage interpolation flaps for reconstruction of these wounds. Examination of our utilization of these flaps based on an anatomic region and surgical approach. A region-based demonstration of flap conceptualization, design, and execution is provided. Tunneled, transposed, and deepithelialized variations of single-stage interpolation flaps provide versatile options for reconstruction of a variety of defects encroaching on or involving free margins. The inherently robust vascularity of these flaps supports importation of necessary tissue bulk while allowing aggressive contouring to restore an intricate native topography. Critical flap design allows access to distant tissue reservoirs and placement of favorable incision lines while preserving the inherent advantages of a single operative procedure.

Ipsilateral pedicled TRAM flaps: the safer alternative?

PubMed

Clugston, P A; Gingrass, M K; Azurin, D; Fisher, J; Maxwell, G P

2000-01-01

Transverse rectus abdominis myocutaneous (TRAM) flap breast reconstruction has become a commonly performed procedure in the 1990s. The original description of the procedure was that of an ipsilaterally based pedicle procedure. Concerns about potential folding of the pedicle with possible compromise of the vascular supply led many surgeons to prefer the contralateral pedicle. Subsequently, there have been several large clinical series of pedicled TRAM flaps showing a relatively high complication rate related to flap vascularity problems. Partial flap necrosis rates in pedicled TRAM series range from 5 to 44 percent. These findings resulted in many centers favoring free TRAM flap breast reconstruction, despite an increase in resource use and negligible differences in complication rates. Ipsilateral pedicle TRAM flap breast reconstruction is not a commonly reported procedure and is reserved for cases for which scars preclude use of the contralateral pedicle. Simplicity and versatility of flap shaping, improved maintenance of the inframammary fold, and lack of disruption of the natural xiphoid hollow give ipsilateral TRAM flaps further advantages. This study reports on a series of 252 consecutive ipsilateral TRAM flap reconstructions in 190 patients. The majority of patients underwent muscle-sparing procedures with preservation of a medial and a lateral strip of rectus muscle. Immediate reconstruction was done in 104 of the 190 patients. Skin-sparing (69 patients) or skin-reduction procedures (21 patients) were used in 90 of the 104 patients (87 percent) undergoing immediate reconstruction. Complication rates were comparable to those of series reported for contralateral TRAM flaps, except that partial flap necrosis (2.0 percent) was less in this series. Risk factors were analyzed with regard to the most common complications seen in this study. Ipsilateral TRAM flap breast reconstruction is our preferred method, if available, because we believe that it has several

Preliminary Design and Evaluation of an Airfoil with Continuous Trailing-Edge Flap

NASA Technical Reports Server (NTRS)

Shen, Jinwei; Thornburgh, Robert P.; Kreshock, Andrew R.; Wilbur, Matthew L.; Liu, Yi

2012-01-01

This paper presents the preliminary design and evaluation of an airfoil with active continuous trailing-edge flap (CTEF) as a potential rotorcraft active control device. The development of structural cross-section models of a continuous trailing-edge flap airfoil is described. The CTEF deformations with MFC actuation are predicted by NASTRAN and UM/VABS analyses. Good agreement is shown between the predictions from the two analyses. Approximately two degrees of CTEF deflection, defined as the rotation angle of the trailing edge, is achieved with the baseline MFC-PZT bender. The 2D aerodynamic characteristics of the continuous trailing-edge flap are evaluated using a CFD analysis. The aerodynamic efficiency of a continuous trailing-edge flap is compared to that of a conventional discrete trailing-edge flap (DTEF). It is found that the aerodynamic characteristics of a CTEF are equivalent to those of a conventional DTEF with the same deflection angle but with a smaller flap chord. A fluid structure interaction procedure is implemented to predict the deflection of the continuous trailingedge flap under aerodynamic pressure. The reductions in CTEF deflection are overall small when aerodynamic pressure is applied: 2.7% reduction is shown with a CTEF deflection angle of two degrees and at angle of attack of six degrees. In addition, newly developed MFC-PMN actuator is found to be a good supplement to MFC-PZT when applied as the bender outside layers. A mixed MFC-PZT and MFC-PMN bender generates 3% more CTEF deformation than an MFC-PZT only bender and 5% more than an MFC-PMN only bender under aerodynamic loads.

Energy management - The delayed flap approach

NASA Technical Reports Server (NTRS)

Bull, J. S.

1976-01-01

Flight test evaluation of a Delayed Flap approach procedure intended to provide reductions in noise and fuel consumption is underway using the NASA CV-990 test aircraft. Approach is initiated at a high airspeed (240 kt) and in a drag configuration that allows for low thrust. The aircraft is flown along the conventional ILS glide slope. A Fast/Slow message display signals the pilot when to extend approach flaps, landing gear, and land flaps. Implementation of the procedure in commercial service may require the addition of a DME navigation aid co-located with the ILS glide slope transmitter. The Delayed Flap approach saves 250 lb of fuel over the Reduced Flap approach, with a 95 EPNdB noise contour only 43% as large.

Risk Factor Analysis of Freestyle Propeller Flaps.

PubMed

Paik, Joo Myong; Pyon, Jai-Kyong

2017-01-01

Background  Freestyle propeller flaps have been widely used as a reconstructive option for both trunk and extremities. It offers the advantage of "like-with-like" reconstruction with an adjacent tissue with no dissection to the source vessels. However, there is the risk of vascular complications. In the present study, the authors investigated the incidence of vascular complications and their risk factors following freestyle propeller flap in the trunk and extremities. Methods  The authors conducted a retrospective review of 50 patients who underwent soft tissue reconstruction of the trunk and the extremities with 55 freestyle propeller flaps from 2004 to 2015. Data regarding patient demographics, surgical details, including the arc of rotation, and flap complications were collected from a prospectively maintained database and analyzed. Results  There were 10 flap complications (18.2%), including 7 superficial partial necrosis, 2 full-thickness partial necrosis, and 1 total necrosis from the 55 freestyle propeller flaps harvested. Previous irradiation was a significant risk factor for flap complications and the propeller flap harvested from the extremities showed a significantly higher rate of complications compared with those harvested from the trunk. Complication rates were higher in flaps with the arc of rotation between 150 and 180 degrees with marginal significance compared with flaps with the arc of rotation less than 150 degrees. Conclusions  Freestyle propeller flaps proved to be a valid and reliable option for reconstruction of defects in the trunk, while complication rate was quite high in the extremities. A prudent preoperative evaluation and preparation may be necessary before performing this surgical technique in the extremities. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Externally blown flap noise research

NASA Technical Reports Server (NTRS)

Dorsch, R. G.

1974-01-01

The Lewis Research Center cold-flow model externally blown flap (EBF) noise research test program is summarized. Both engine under-the-wing and over-the-wing EBF wing section configurations were studied. Ten large scale and nineteen small scale EBF models were tested. A limited number of forward airspeed effect and flap noise suppression tests were also run. The key results and conclusions drawn from the flap noise tests are summarized and discussed.

14 CFR 25.1511 - Flap extended speed.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flap extended speed. 25.1511 Section 25... Limitations § 25.1511 Flap extended speed. The established flap extended speed V FE must be established so that it does not exceed the design flap speed V F chosen under §§ 25.335(e) and 25.345, for the...

14 CFR 25.1511 - Flap extended speed.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Flap extended speed. 25.1511 Section 25... Limitations § 25.1511 Flap extended speed. The established flap extended speed V FE must be established so that it does not exceed the design flap speed V F chosen under §§ 25.335(e) and 25.345, for the...

Comparison of morbidity-related seroma formation following conventional latissimus dorsi flap versus muscle-sparing latissimus dorsi flap breast reconstruction

PubMed Central

Numajiri, Toshiaki; Nakatsukasa, Katsuhiko; Sakaguchi, Koichi; Taguchi, Tetsuya

2017-01-01

Purpose The pedicled, descending-branch muscle-sparing latissimus dorsi (MSLD) flap has been widely used for breast reconstruction following total mastectomy. However, the superiority of the MSLD flap compared to the conventional latissimus dorsi (CLD) flap in preventing seroma formation has not been demonstrated. This study compares the morbidities related to seroma formation following pedicled MSLD flap and CLD flap breast reconstruction. Methods A total of 15 women who underwent partial mastectomy and immediate partial breast reconstruction with MSLD flaps were compared with 15 women under identical conditions with CLD flap breast reconstruction. The medical records were reviewed for both complications and demographic data. The authors compared morbidity, including donor-site seroma, total volume of drain discharge, indwelling period of drainage, and length of hospital stay following both MSLD flap and CLD flap breast reconstruction. Results The demographic data of the 2 groups were not significantly different. Donor-site seroma occurred in 2 MSLD patients (13.3%) and in 6 CLD patients (40.0%). The total volume of the drain discharge and the indwelling period of drainage at donor site were significantly lower in the MSLD group. The length of hospital stay was significantly shorter (by approximately a day and a half) for the MSLD group. Conclusion The MSLD flap, with its low complication rate and associated minimal functional and aesthetic deficits at the donor site, may be a useful option for small breast reconstruction if earlier discharge from hospital is demanded. PMID:28932726

Comparison of morbidity-related seroma formation following conventional latissimus dorsi flap versus muscle-sparing latissimus dorsi flap breast reconstruction.

PubMed

Sowa, Yoshihiro; Numajiri, Toshiaki; Nakatsukasa, Katsuhiko; Sakaguchi, Koichi; Taguchi, Tetsuya

2017-09-01

The pedicled, descending-branch muscle-sparing latissimus dorsi (MSLD) flap has been widely used for breast reconstruction following total mastectomy. However, the superiority of the MSLD flap compared to the conventional latissimus dorsi (CLD) flap in preventing seroma formation has not been demonstrated. This study compares the morbidities related to seroma formation following pedicled MSLD flap and CLD flap breast reconstruction. A total of 15 women who underwent partial mastectomy and immediate partial breast reconstruction with MSLD flaps were compared with 15 women under identical conditions with CLD flap breast reconstruction. The medical records were reviewed for both complications and demographic data. The authors compared morbidity, including donor-site seroma, total volume of drain discharge, indwelling period of drainage, and length of hospital stay following both MSLD flap and CLD flap breast reconstruction. The demographic data of the 2 groups were not significantly different. Donor-site seroma occurred in 2 MSLD patients (13.3%) and in 6 CLD patients (40.0%). The total volume of the drain discharge and the indwelling period of drainage at donor site were significantly lower in the MSLD group. The length of hospital stay was significantly shorter (by approximately a day and a half) for the MSLD group. The MSLD flap, with its low complication rate and associated minimal functional and aesthetic deficits at the donor site, may be a useful option for small breast reconstruction if earlier discharge from hospital is demanded.

Comparison of Tear cytokines and clinical outcomes between off-flap and on-flap epi-LASIK with mitomycin C.

PubMed

Zhang, Yu; Chen, Yue-Guo; Xia, Ying-Jie; Qi, Hong

2012-09-01

To compare tear cytokines and clinical outcomes between off-flap and on-flap epi-LASIK eyes and explore the possible mechanism for the clinical differences. This double-masked, randomized study enrolled 18 myopic patients who underwent off-flap epi-LASIK with mitomycin C (MMC) in 1 eye and on-flap epi-LASIK with MMC in the contralateral eye. Tears were collected from each eye preoperatively and 2 hours, 1 day, and 5 days postoperatively. Concentrations of multiple tear cytokines were measured by a multiplex immunobead assay. Uncorrected distance visual acuity (UDVA), refraction, haze scores, pain scores, and percentage of corneal epithelial healing were evaluated. Compared with the on-flap group, the off-flap group had outcomes of better UDVA and higher percentages of epithelial healing at 5 days after surgery (P<.001) and lower levels of haze at 1 month after surgery (P=.049). Preoperatively, no significant differences were noted in the release rate of all tear cytokines between groups. At 2 hours postoperatively, the release rate of tear basic fibroblast growth factor (bFGF), platelet-derived growth factor-BB (PDGF-BB), interleukin-8 (IL-8), and tumor necrosis factor alpha (TNF-α) in the off-flap group were significantly lower than those in the on-flap group (P=.011, .017, .048, and .041, respectively). Off-flap epi-LASIK with MMC offers faster corneal epithelial healing and visual recovery, and temporary less haze than on-flap epi-LASIK with MMC. The lower tear levels of bFGF, PDGF-BB, IL-8, and TNF-α in the offflap group 2 hours after surgery may suggest a possible mechanism for the clinical differences. Copyright 2012, SLACK Incorporated.

Reconstruction of Facial Defect Using Deltopectoral Flap.

PubMed

Aldelaimi, Tahrir N; Khalil, Afrah A

2015-11-01

Reconstruction of the head and neck is a challenge for otolarygology surgeons, maxillofacial surgeons as well as plastic surgeons. Defects caused by the resection and/or trauma should be closed with flaps which match in color, texture and hair bearing characteristics with the face. Deltopectoral flap is a one such flap from chest and neck skin mainly used to cover the facial defects. This study report a patient presenting with tragic Road Traffic Accident (RTA) admitted to maxillofacial surgery department at Ramadi Teaching Hospital, Anbar province, Iraq. An incision, medially based, was done and deltopectoral fascio-cutaneous flap was used for surgical exposure and closure of defects after RTA. There was no major complication. Good aesthetic and functional results were achieved. Deltopectoral flap is an excellent alternative for the reconstruction of head and neck. Harvesting and application of the flap is rapid and safe. Only a single incision is sufficient for dissection and flap elevation.

Innervated boomerang flap for finger pulp reconstruction.

PubMed

Chen, Shao-Liang; Chiou, Tai-Fung

2007-11-01

The boomerang flap originates from the dorsolateral aspect of the proximal phalanx of an adjacent digit and is supplied by the retrograde blood flow through the vascular arcades between the dorsal and palmar digital arteries. To provide sensation of the boomerang flap for finger pulp reconstruction, the dorsal sensory branch of the proper digital nerve and the superficial sensory branch of the corresponding radial or ulnar nerve are included within the skin flap. After transfer of the flap to the injured site, epineural neurorrhaphies are done between the digital nerves of the pulp and the sensory branches of the flap. We used this sensory flap in five patients, with more than 1 year follow-up, and all patients achieved measurable two-points discrimination. The boomerang flap not only preserves the proper palmar digital artery but also provides an extended and innervated skin paddle. It seems to be an alternative choice for one-stage reconstruction of major pulp defect.

Aerothermal Assment Of The Expert Flap In The SCIROCCO Wind Tunnel

NASA Astrophysics Data System (ADS)

Walpot, L.; Di Clemente, M.; Vos, J.; Etchells, J.; Trifoni, E.; Thoemel, J.; Gavira, J.

2011-05-01

In the frame of the “In-Flight Test Measurement Techniques for Aerothermodynamics” activity of the EXPERT Program, the EXPERT Instrumented Open Flap Assembly experiment has the objective to verify the design/sensor integration and validate the CFD tools. Ground based measurements were made in Europe’s largest high enthalpy plasma facility, Scirocco in Italy. Two EXPERT flaps of the flight article, instrumented with 14 thermocouples, 5 pressure ports, a pyrometer and an IR camera mounted in the cavity instrumented flap will collect in-flight data. During the Scirocco experiment, an EXPERT flap model identical to the flight article was mounted at 45 deg on a holder including cavity and was subjected to a hot plasma flow at an enthalpy up to 11MJ/kg at a stagnation pressure of 7 bar. The test model sports the same pressure sensors as the flight article. Hypersonic state-of-the-art codes were then be used to perform code-to-code and wind tunnel-to-code comparisons, including thermal response of the flap as collected during the tests by the sensors and camera.

Removing the Active-Site Flap in Lipase A from Candida antarctica Produces a Functional Enzyme without Interfacial Activation.

PubMed

Wikmark, Ylva; Engelmark Cassimjee, Karim; Lihammar, Richard; Bäckvall, Jan-E

2016-01-01

A mobile region is proposed to be a flap that covers the active site of Candida antarctica lipase A. Removal of the mobile region retains the functional properties of the enzyme. Interestingly interfacial activation, required for the wild-type enzyme, was not observed for the truncated variant, although stability, activity, and stereoselectivity were very similar for the wild-type and variant enzymes. The variant followed classical Michaelis-Menten kinetics, unlike the wild type. Both gave the same relative specificity in the transacylation of a primary and a secondary alcohol in organic solvent. Furthermore, both showed the same enantioselectivity in transacylation of alcohols and the hydrolysis of alcohol esters, as well as in the hydrolysis of esters chiral at the acid part. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Refining the intrinsic chimera flap: a review.

PubMed

Agarwal, Jayant P; Agarwal, Shailesh; Adler, Neta; Gottlieb, Lawrence J

2009-10-01

Reconstruction of complex tissue deficiencies in which each missing component is in a different spatial relationship to each other can be particularly challenging, especially in patients with limited recipient vessels. The chimera flap design is uniquely suited to reconstruct these deformities. Chimera flaps have been previously defined in many ways with 2 main categories: prefabricated or intrinsic. Herein we attempt to clarify the definition of a true intrinsic chimeric flap and provide examples of how these constructs provide a method for reconstruction of complex defects. The versatility of the intrinsic chimera flap and its procurement from 7 different vascular systems is described. A clarification of the definition of a true intrinsic chimera flap is described. In addition, construction of flaps from the lateral femoral circumflex, deep circumflex iliac, inferior gluteal, peroneal, subscapular, thoracodorsal, and radial arterial systems is described to showcase the versatility of these chimera flaps. A true intrinsic chimera flap must consist of more than a single tissue type. Each of the tissue components receives its blood flow from separate vascular branches or perforators that are connected to a single vascular source. These vascular branches must be of appropriate length to allow for insetting with 3-dimensional spatial freedom. There are a multitude of sites from which true intrinsic chimera flaps may be harvested.

To flap or not to flap: a discussion between a fish and a jellyfish

NASA Astrophysics Data System (ADS)

Martin, Nathan; Roh, Chris; Idrees, Suhail; Gharib, Morteza

2016-11-01

Fish and jellyfish are known to swim by flapping and by periodically contracting respectively, but which is the more effective propulsion mechanism? In an attempt to answer this question, an experimental comparison is made between simplified versions of these motions to determine which generates the greatest thrust for the least power. The flapping motion is approximated by pitching plates while periodic contractions are approximated by clapping plates. A machine is constructed to operate in either a flapping or a clapping mode between Reynolds numbers 1,880 and 11,260 based on the average plate tip velocity and span. The effect of the total sweep angle, total sweep time, plate flexibility, and duty cycle are investigated. The average thrust generated and power required per cycle are compared between the two modes when their total sweep angle and total sweep time are identical. In general, operating in the clapping mode required significantly more power to generate a similar thrust compared to the flapping mode. However, modifying the duty cycle for clapping caused the effectiveness to approach that of flapping with an unmodified duty cycle. These results suggest that flapping is the more effective propulsion mechanism within the range of Reynolds numbers tested. This work was supported by the Charyk Bio-inspired Laboratory at the California Institute of Technology, the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469, and the Summer Undergraduate Research Fellowships program.

Aeroacoustic Measurements of a Wing-Flap Configuration

NASA Technical Reports Server (NTRS)

Meadows, Kristine R.; Brooks, Thomas F.; Humphreys, William M.; Hunter, William H.; Gerhold, Carl H.

1997-01-01

Aeroacoustic measurements are being conducted to investigate the mechanisms of sound generation in high-lift wing configurations, and initial results are presented. The model is approximately 6 percent of a full scale configuration, and consists of a main element NACA 63(sub 2) - 215 wing section and a 30 percent chord half-span flap. Flow speeds up to Mach 0.17 are tested at Reynolds number up to approximately 1.7 million. Results are presented for a main element at a 16 degree angle of attack, and flap deflection angles of 29 and 39 degrees. The measurement systems developed for this test include two directional arrays used to localize and characterize the noise sources, and an array of unsteady surface pressure transducers used to characterize wave number spectra and correlate with acoustic measurements. Sound source localization maps show that locally dominant noise sources exist on the flap-side edge. The spectral distribution of the noise sources along the flap-side edge shows a decrease in frequency of the locally dominant noise source with increasing distance downstream of the flap leading edge. Spectra are presented which show general spectral characteristics of Strouhal dependent flow-surface interaction noise. However, the appearance of multiple broadband tonal features at high frequency indicates the presence of aeroacoustic phenomenon following different scaling characteristics. The scaling of the high frequency aeroacoustic phenomenon is found to be different for the two flap deflection angles tested. Unsteady surface pressure measurements in the vicinity of the flap edge show high coherence levels between adjacent sensors on the flap-side edge and on the flap edge upper surface in a region which corresponds closely to where the flap-side edge vortex begins to spill over to the flap upper surface. The frequency ranges where these high levels of coherence occur on the flap surface are consistent with the frequency ranges in which dominant features

[COMPARISON OF REPAIR EFFECT BETWEEN CHIMERIC ANTEROLATERAL THIGH FLAP AND SERIES-WOUND FLAPS FOR DEFECT AFTER RESECTION OF ORAL AND MAXILLOFACIAL CANCER].

PubMed

Yang, Heping; Zhang, Hongwu; Chen, Haidi; Yang, Shuxiong; Wang, Jun; Hu, Dawang

2016-04-01

To compare the effectiveness of complex defects repair between using chimeric anterolateral thigh flap and series-wound flaps after resection of oral and maxillofacial cancer. After resection of oral and maxillofacial cancer, defect was repaired with chimeric anterolateral thigh flap in 39 patients between January 2011 and July 2014 (chimeric anterolateral thigh flap group); and defect was repaired with series-wound flaps in 35 patients between January 2009 and December 2010 (series-wound flaps group). There was no significant difference in gender, age, duration of disease, tumor type, tumor staging, defect location, and defect area between 2 groups (P > 0.05). The operation time, flap harvesting and microvascular anastomosis time, stomach tube extraction time, and oral feeding time were recorded and compared between 2 groups, and postoperative complications were observed; the effectiveness was evaluated according to clinical efficacy evaluation table of bone and soft tissue defects reconstruction surgery in oral and maxillofacial region. Vascular crisis occurred in 2 cases of chimeric anterolateral thigh flap group, and 4 cases of series-wound flaps group. Partial necrosis appeared at distal end of a series-wound flaps, and oral fistula and infection developed in 3 series-wound flaps. The other flaps and the grafted skin at donor site survived; wounds at recipient site healed by first intention. The operation time, stomach tube extraction time, and oral feeding time of chimeric anterolateral thigh flap group were significantly shorter than those of series-wound flaps group (P < 0.05), while the flap harvesting and microvascular anastomosis time was significantly longer than that of series-wound flaps group (P < 0.05). The patients were followed up 1-5 years (mean, 2.5 years). At 3 months after operation, the appearance, patients' satisfaction, working conditions, oral closure function, chew, language performance, and swallowing scores of the chimeric anterolateral

Comparative study of functional and aesthetically outcomes of reverse digital artery and reverse dorsal homodigital island flaps for fingertip repair.

PubMed

Chen, Q Z; Sun, Y C; Chen, J; Kong, J; Gong, Y P; Mao, T

2015-11-01

This retrospective study was designed to compare functional and cosmetic outcomes of the reverse digital artery island flap and reverse dorsal homodigital island flap in fingertip repair. A total of 23 patients were followed for 24 to 30 months. The reverse digital artery island flap was used in 12 patients, and reverse dorsal homodigital island flap in another 11 patients. Flap sensibility was assessed using the Semmes-Weinstein monofilament test and static 2-point discrimination test. Patient satisfaction, active motion of the finger joints, complications and cold intolerance were evaluated. The static 2-point discrimination and Michigan Hand Outcomes Questionnaire (appearance) of the fingers treated with a reverse digital artery flap were significantly better than those with a reverse dorsal homodigital flap. The static 2-point discrimination of the skin-grafted donor sides after dorsal homodigital flap were poorer than that in the contralateral finger. No significant differences were found between the two flaps for pressure or touch sensibility, active ranges of digital motion, complications and cold intolerance. III. © The Author(s) 2015.

The First Dorsal Metatarsal Artery Perforator Propeller Flap.

PubMed

Hallock, Geoffrey G

2016-06-01

Distal foot and toe defects requiring a vascularized flap for coverage have very limited options, oftentimes justifying even a free flap. Perforator flaps in general and propeller flaps in particular have opened up an entirely new subset of local tissue transfer alternatives that can potentially avoid the difficulties that accompany microvascular tissue transfers. The first dorsal metatarsal artery (FDMA) perforator propeller flap represents another variation of this theme. A standard FDMA flap from the dorsum of the foot was raised in reversed fashion based on the distal communicating branch or "perforator" from the plantar foot circulation in 2 patients with great toe defects. All distal skin tissue between this perforator and the defect was kept with the FDMA flap as an attached minor blade, to thereby create an FDMA propeller flap. Salvage of the great toe in both patients was achieved. The benefit of the minor blade of the propeller was to fill a portion of the donor site defect of the traditional FDMA major blade, to permit tension-free donor site closure of the dorsal foot without sequela. The distal-based FDMA flap can be useful as a local flap for coverage of distal foot and toe wounds, but direct donor site closure can be problematic as mirrored by its relative the dorsalis pedis flap. The FDMA perforator propeller flap variation can achieve the same reconstructive goals while simultaneously transferring vascularized tissue into the dorsal foot donor site to thereby minimize the tension if direct closure is possible or minimize the need for a skin graft in this notoriously difficult region.

Experimental study on axial pedicled composite flap prefabrication with high density porous polyethylene implants: medporocutaneous flap.

PubMed

Kocman, A Emre; Kose, Aydan A; Karabagli, Yakup; Baycu, Cengiz; Cetin, Cengiz

2008-01-01

Composite flaps including soft tissues with bone or cartilage are widely used in reconstruction of three-dimensional defects, but have some disadvantages. Flap prefabrication with alloplastic implants is an alternative procedure. Axial pattern vascularised high density porous polyethylene (HDPP) implants are capable of sustaining skin grafts. The purpose of this study was to examine the vascularisation pattern of the skin island in a composite flap prefabrication model prepared with vascularised HDPP implants. Forty male Wistar rats divided into four groups were used. A 9.5 x 6 x 2 mm HDPP block was centered on the dissected saphenous pedicle and anchored under the abdominal skin in the experimental group I (n=10). In experimental group II (n=10) saphenous artery and vein were put between the skin and the implant. Thus, the structures were laid as skin, HDPP block, pedicle in experimental group I and skin, pedicle, HDPP block in experimental group II. HDPP block-implanted and pedicle-implanted only groups served as control groups I and II, respectively. Eight weeks after prefabrication, skin islands 1.5 x 5 cm in size incorporated with implants were elevated based on saphenous vessels in the experimental groups and skin islands only based on the pedicle in control group II. Skin islands of the same dimensions were raised as grafts in control group I. Nylon sheets were put under the flaps and grafts to prevent vascularisation from the recipient bed. Flap viability was assessed by measuring the surface area on the 7th day. Total necrosis developed in composite grafts of control group I. Flap survival was higher in experimental group II and control group II (45% and 46.8%) than in group I (29.28%). Histologic studies demonstrated fibrovascular ingrowth into the HDPP implants, except in control group I, with significant inflammatory response and necrosis. Vascularisation of skin and implants from the pedicle was seen also microangiographically. In conclusion, a

Retention of a reconstructed nipple using a C-V flap with different layer thicknesses in the C-flap.

PubMed

Sowa, Yoshihiro; Itsukage, Sizu; Sakaguchi, Kouichi; Taguchi, Tetsuya; Numajiri, Toshiaki

2018-04-01

The C-V flap for nipple reconstruction is now one of standard surgical techniques. But decreased projection is still a problem. In recent years, it has been suggested that projection can be more easily maintained when raising of the C-flap is performed with a split thickness dermis. In this study, we examined whether decrease of projection can be prevented by raising of a C-flap with a split dermis rather than with full dermis. A total of 49 consecutive patients who underwent reconstruction of a nipple using the C-V flap technique were enrolled. The patients included 22 who underwent surgery using a C-flap with a full thickness dermis (Group F), and 27 who underwent surgery with raising of a flap with a split thickness dermis (Group S). The size of the reconstructed nipple was measured at 2 weeks, 6 months and 1 year postoperatively for comparison between Groups F and S. Partial necrosis of the C-flap end occurred in 4 subjects in only Group S. The decrease in projection after 1 year postoperatively in Group S was significantly lower than that in Group F. In contrast, the teat base size in Group F tended to be greater than that in Group S, suggesting a tendency for an expanded base using a flap with a full dermis. Our results indicated that it is recommended to use a C-flap with a split dermis for cases with high projection of the nipple on the contralateral side.

Parasacral Perforator Flaps for Reconstruction of Sacral Pressure Sores.

PubMed

Lin, Chin-Ta; Chen, Shih-Yi; Chen, Shyi-Gen; Tzeng, Yuan-Sheng; Chang, Shun-Cheng

2015-07-01

Despite advances in reconstruction techniques, pressure sores continue to present a challenge to the plastic surgeon. The parasacral perforator flap is a reliable flap that preserves the entire contralateral side as a future donor site. On the ipsilateral side, the gluteal muscle itself is preserved and all flaps based on the inferior gluteal artery are still possible. We present our experience of using parasacral perforator flaps in reconstructing sacral defects. Between August 2004 and January 2013, 19 patients with sacral defects were included in this study. All the patients had undergone surgical reconstruction of sacral defects with a parasacral perforator flap. The patients' sex, age, cause of sacral defect, flap size, flap type, numbers of perforators used, rotation angle, postoperative complications, and hospital stay were recorded. There were 19 parasacral perforator flaps in this series. All flaps survived uneventfully except for 1 parasacral perforator flap, which failed because of methicillin-resistant Staphylococcus aureus infection. The overall flap survival rate was 95% (18/19). The mean follow-up period was 17.3 months (range, 2-24 months). The average length of hospital stay was 20.7 days (range, 9-48 days). No flap surgery-related mortality was found. Also, there was no recurrence of sacral pressure sores or infected pilonidal cysts during the follow-up period. Perforator-based flaps have become popular in modern reconstructive surgery because of low donor-site morbidity and good preservation of muscle. Parasacral perforator flaps are durable and reliable in reconstructing sacral defects. We recommend the parasacral perforator flap as a good choice for reconstructing sacral defects.

Pressure Distributions for the GA(W)-2 Airfoil with 20% Aileron, 25% Slotted Flap and 30% Fowler Flap

NASA Technical Reports Server (NTRS)

Wentz, W. H., Jr.; Fiscko, K. A.

1978-01-01

Surface pressure distributions were measured for the 13% thick GA(W)-2 airfoil section fitted with 20% aileron, 25% slotted flap and 30% Fowler flap. All tests were conducted at a Reynolds number of 2.2 x 10 to the 6th power and a Mach number of 0.13. Pressure distribution and force and moment coefficient measurements are compared with theoretical results for a number of cases. Agreement between theory and experiment is generally good for low angles of attack and small flap deflections. For high angles and large flap deflections where regions of separation are present, the theory is inadequate. Theoretical drag predictions are poor for all flap-extended cases.

The possibility for use of venous flaps in plastic surgery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baytinger, V. F., E-mail: baitinger@mail.tomsknet.ru; Kurochkina, O. S., E-mail: kurochkinaos@yandex.ru; Selianinov, K. V.

2015-11-17

The use of venous flaps is controversial. The mechanism of perfusion of venous flaps is still not fully understood. The research was conducted on 56 white rats. In our experimental work we studied two different models of venous flaps: pedicled venous flap (PVF) and pedicled arterialized venous flap (PAVF). Our results showed that postoperative congestion was present in all flaps. However 66.7% of all pedicled venous flaps and 100% of all pedicled arterialized venous flaps eventually survived. Histological examination revealed that postoperatively the blood flow in the skin of the pedicled arterialized venous flap became «re-reversed» again; there were nomore » differences between mechanism of survival of venous flaps and other flaps. On the 7-14th day in the skin of all flaps were processes of neoangiogenesis and proliferation. Hence the best scenario for the clinical use of venous flaps unfolds when both revascularization and skin coverage are required.« less

Microsurgical free flaps: Controversies in maxillofacial reconstruction

PubMed Central

George, Rinku K.; Krishnamurthy, Arvind

2013-01-01

Reconstructive microsurgery for oral and maxillofacial (OMF) defects is considered as a niche specialty and is performed regularly only in a handful of centers. Till recently the pectoralis major myocutaneous flap (PMMC) was considered to be the benchmark for OMF reconstruction. This philosophy is changing fast with rapid advancement in reconstructive microsurgery. Due to improvement in instrumentation and the development of finer techniques of flap harvesting we can positively state that microsurgery has come of age. Better techniques, microscopes and micro instruments enable us to do things previously unimaginable. Supramicrosurgery and ultrathin flaps are a testimony to this. Years of innovation in reconstructive microsurgery have given us a reasonably good number of very excellent flaps. Tremendous work has been put into producing some exceptionally brilliant research articles, sometimes contradicting each other. This has led to the need for clarity in some areas in this field. This article will review some controversies in reconstructive microsurgery and analyze some of the most common microvascular free flaps (MFF) used in OMF reconstruction. It aims to buttress the fact that three flaps-the radial forearm free flap (RFFF), anterolateral thigh flap (ALT) and fibula are the ones most expedient in the surgeon's arsenal, since they can cater to almost all sizeable defects we come across after ablative surgery in the OMF region. They can thus aptly be titled as the workhorses of OMF reconstruction with regard to free flaps. PMID:23662264

The gust-mitigating potential of flapping wings.

PubMed

Fisher, Alex; Ravi, Sridhar; Watkins, Simon; Watmuff, Jon; Wang, Chun; Liu, Hao; Petersen, Phred

2016-08-02

Nature's flapping-wing flyers are adept at negotiating highly turbulent flows across a wide range of scales. This is in part due to their ability to quickly detect and counterract disturbances to their flight path, but may also be assisted by an inherent aerodynamic property of flapping wings. In this study, we subject a mechanical flapping wing to replicated atmospheric turbulence across a range of flapping frequencies and turbulence intensities. By means of flow visualization and surface pressure measurements, we determine the salient effects of large-scale freestream turbulence on the flow field, and on the phase-average and fluctuating components of pressure and lift. It is shown that at lower flapping frequencies, turbulence dominates the instantaneous flow field, and the random fluctuating component of lift contributes significantly to the total lift. At higher flapping frequencies, kinematic forcing begins to dominate and the flow field becomes more consistent from cycle to cycle. Turbulence still modulates the flapping-induced flow field, as evidenced in particular by a variation in the timing and extent of leading edge vortex formation during the early downstroke. The random fluctuating component of lift contributes less to the total lift at these frequencies, providing evidence that flapping wings do indeed provide some inherent gust mitigation.

Pressure Distribution Over Airfoils with Fowler Flaps

NASA Technical Reports Server (NTRS)

Wenzinger, Carl J; Anderson, Walter B

1938-01-01

Report presents the results of tests made of a Clark y airfoil with a Clark y Fowler flap and of an NACA 23012 airfoil with NACA Fowler flaps. Some of the tests were made in the 7 by 10-foot wind tunnel and others in the 5-foot vertical wind tunnel. The pressures were measured on the upper and lower surfaces at one chord section both on the main airfoils and on the flaps for several angles of attack with the flaps located at the maximum-lift settings. A test installation was used in which the model was mounted in the wind tunnel between large end planes so that two-dimensional flow was approximated. The data are given in the form of pressure-distribution diagrams and as plots of calculated coefficients for the airfoil-and-flap combinations and for the flaps alone.

Reconstruction of Large Postburn Facial-Scalp Scars by Expanded Pedicled Deltopectoral Flap and Random Scalp Flap: Technique Improvements to Enlarge the Reconstructive Territory.

PubMed

Ma, Xianjie; Li, Yang; Li, Weiyang; Liu, Chaohua; Peng, Pai; Song, Baoqiang; Xia, Wensen; Yi, Chenggang; Lu, Kaihua; Su, Yingjun

2017-09-01

The scars of face and scalp caused by burning often show as 1 large facial-scalp scar. The deltopectoral flap was recognized as one of the first choices for the facial scar reconstruction. However, this flap cannot cross the level of zygomatic arch traditionally when it was transferred with pedicle. When the flap reconstructed the facial-scalp scars with expanded random scalp flap, another flap was often needed to reconstruct the remaining temple and forehead scars. The authors reviewed 24 patients of large facial-scalp scars reconstructed by expanded pedicled deltopectoral flap and scalp flap with several technique improvements. The seaming scar between the deltopectoral flap and scalp flap in the temple region formed the new hairline. The technique improvements included ligation of the perforating branches of the transverse cervical artery and thoracoacromial artery when dissecting the pocket, the partial bolster compressive dressing to the distal part of the flap and dividing the pedicle partly as a delaying procedure before dividing the pedicle completely. Good skin compliance, normal contours, and emotional expression were noted. There were complications including expander exposure in 3 patients, stretch marks in 5 patients, flap tip necrosis in 2 patients, and mild postoperative hypertrophic scars in 3 patients. In conclusion, the expanded pedicled deltopectoral flap can enlarge the reconstructive territory in face successfully with the technique improvements. The combination of the expanded pedicled deltopectoral flap and scalp flap is a reliable and excellent reconstructive option for large postburn facial-scalp scars.

[Pedicled versus free TRAM flap for breast reconstruction].

PubMed

Galla, T J; Lukas, B; Feller, A M

1999-03-01

In breast reconstruction, the free TRAM-flap offers many advantages over the pedicled TRAM-flap. Due to its superior perfusion, the free flap rarely develops necrosis. Shaping of the flap is easier due to the lack of the thick muscle pedicle. Because the rectus muscle is spared, there is minimal donor site morbidity. However, the necessary microvascular anastomoses reduced the acceptance of the free TRAM-flap. During a 13-months period, 51 breast reconstructions were performed in 41 patients, 31 unilateral and ten bilateral. 45 flaps served for delayed reconstruction and six flaps for immediate reconstruction. The operations were performed by two teams working simultaneously. The average operating time was 3.9 hours for unilateral and 6.9 hours for bilateral delayed reconstruction. For immediate reconstruction, 6.2 and 6.3 hours were required for uni- and bilateral procedures, respectively. In 38 flaps, the thoracodorsal vessels served as recipient vessels; 13 flaps were anastomosed to the internal mammary artery and vein. Postoperative complications were observed in 13 patients. Three vessel anastomoses had to be revised. In one flap, a partial necrosis occurred; in two flaps hematoma evacuation was necessary. Two patients suffered from fat necroses at the abdomen and one umbilicus was lost. Skin irritations and seromas at the abdomen occurred in five patients. Pulmonary embolism was diagnosed in one patient three weeks postoperatively. Abdominal hernias or bulging in the epigastric area were not observed up to 15 months after reconstruction. These results reveal a low complication rate for breast reconstruction with the free TRAM-flap. The advantages of this technique as compared to the pedicled technique are discussed.

Vortex leading edge flap assembly for supersonic airplanes

NASA Technical Reports Server (NTRS)

Rudolph, Peter K. C. (Inventor)

1997-01-01

A leading edge flap (16) for supersonic transport airplanes is disclosed. In its stowed position, the leading edge flap forms the lower surface of the wing leading edge up to the horizontal center of the leading edge radius. For low speed operation, the vortex leading edge flap moves forward and rotates down. The upward curve of the flap leading edge triggers flow separation on the flap and rotational flow on the upper surface of the flap (vortex). The rounded shape of the upper fixed leading edge provides the conditions for a controlled reattachment of the flow on the upper wing surface and therefore a stable vortex. The vortex generates lift and a nose-up pitching moment. This improves maximum lift at low speed, reduces attitude for a given lift coefficient and improves lift to drag ratio. The mechanism (27) to move the vortex flap consists of two spanwise supports (24) with two diverging straight tracks (64 and 68) each and a screw drive mechanism (62) in the center of the flap panel (29). The flap motion is essentially normal to the airloads and therefore requires only low actuation forces.

Release of hand burn contracture: comparing the ALT perforator flap with the gracilis free flap with split skin graft.

PubMed

Misani, M; Zirak, C; Hau, Lê Thua Trung; De Mey, A; Boeckx, W

2013-08-01

The use of microsurgery in the management of burn sequelae is not a new idea. According to the properties of various types of free flaps different goals can be achieved or various additional procedures have to be combined. We report the comparison of two different free flaps on a single patient for reconstruction of both upper extremities for burn sequelae. A 1-year-old child sustained severe burns on both hands, arms and thorax and was initially only treated conservatively. This resulted in severe contractures. At the age of 4-years a free gracilis flap was selected for reconstruction of his left hand and a free anterolateral thigh flap for the right hand. We noticed a better functional and esthetic result for the gracilis flap associated with a shorter operative time and a minor donor site morbidity. The intraoperative technique and time, postoperative complications, functional and esthetic results and donor site morbidities were studied in the two types of flaps chosen. A review of literature was also performed. Our experience reported a better success of the gracilis muscle flap covered with a split skin graft compared to the anterolateral thigh flap in the reconstruction of hand function after severe burn sequelae. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

Flap Reconstruction for Pressure Ulcers: An Outcomes Analysis

PubMed Central

Madden, James J.; Hoffman, Ashley N.; Kim, Justine S.; Thayer, Wesley P.; Nanney, Lillian B.; Spear, Marcia E.

2017-01-01

Background: Historically, complication rates after pressure ulcer reconstruction utilizing flap coverage have been high. Patients undergoing operations for pressure ulcer coverage typically have multiple risk factors for postoperative complications. The purpose of this study was to examine a large patient series in the pressure ulcer population to uncover objective evidence of the linkage between risk factors and outcomes after flap coverage. Methods: This study was a retrospective chart review of patients who underwent flap reconstruction for a pressure ulcer between 1997 and 2015. The characteristics of patients were analyzed to determine those who had complications such as pressure ulcer recurrence, wound dehiscence, and wound infection. Results: All patients (N = 276) underwent flap coverage of their pressure ulcers. The overall complication rate was 58.7% (162 patients). Wound dehiscence was the most common complication (31.2%), and the pressure ulcer recurrence rate was 28.6%. Multivariate regression for pressure ulcer recurrence revealed that body mass index <18.5 [relative risk (RR) 3.13], active smoking (RR 2.33), and ischial pressure ulcers (RR 3.46) were independent risk factors for pressure ulcer recurrence. Ischial pressure ulcers (RR 2.27) and preoperative osteomyelitis (RR 2.78) were independent risk factors for wound dehiscence. Diabetes was an independent risk factor for wound infection (RR 4.34). Conclusions: Our retrospective analysis revealed numerous factors that are associated with high rates of major postoperative complications. Risk factors must be taken into account when offering flap coverage, and risk-reducing strategies must be implemented in patients before pressure ulcer reconstruction. PMID:28203494

Sequence, Structural Analysis and Metrics to Define the Unique Dynamic Features of the Flap Regions Among Aspartic Proteases.

PubMed

McGillewie, Lara; Ramesh, Muthusamy; Soliman, Mahmoud E

2017-10-01

Aspartic proteases are a class of hydrolytic enzymes that have been implicated in a number of diseases such as HIV, malaria, cancer and Alzheimer's. The flap region of aspartic proteases is a characteristic unique structural feature of these enzymes; and found to have a profound impact on protein overall structure, function and dynamics. Flap dynamics also plays a crucial role in drug binding and drug resistance. Therefore, understanding the structure and dynamic behavior of this flap regions is crucial in the design of potent and selective inhibitors against aspartic proteases. Defining metrics that can describe the flap motion/dynamics has been a challenging topic in literature. This review is the first attempt to compile comprehensive information on sequence, structure, motion and metrics used to assess the dynamics of the flap region of different aspartic proteases in "one pot". We believe that this review would be of critical importance to the researchers from different scientific domains.

[APPLICATION VALUE OF INDOCYANINE GREEN ANGIOGRAPHY IN FLAP RECONSTRUCTIVE SURGERY].

PubMed

Yang, Kai; Mu, Lan; Liu, Yan; Peng, Zhe; Li, Guangxue

2015-09-01

To investigate the utility of indocyanine green angiography in flap reconstructive surgery and possibility of decrease the complications. Indocyanine green angiography was performed on 14 patients undergoing flap reconstructive surgery between February and December 2014 to evaluate the blood perfusion of the flap and to adjust the operation plan. Of 14 cases, 2 were male and 12 were female, aged 23-58 years (mean, 35.5 years); 11 flaps were used for breast reconstruction [including 3 free deep inferior epigastric antery perforator (DIEP) flaps, 4 pedicled transverse rectus abdominis myocutaneous flaps (TRAM), 2 pedicled TRAM and free TRAM, and 2 pedicled latissimus dorsi myocutaneous flaps and prosthesis], 1 pedicled latissimus dorsi myocutaneous flap for repairing chest wall defect, 1 pedicled profunda artery perforator (PAP) flap for upper leg defect, and 1 pedicled descending genicular artery perforator flap for knee defect. The size of the flaps ranged from 9 cm x 6 cm to 26 cm x 12 cm. A total of 32 indocyanine green angiography were performed. There was no adverse reactions to the infusion of indocyanine green. The surgery management was adjusted according to results of indocyanine green angiography findings in 5 of 14 cases. The distal part of flap were discarded because of poor perfusion in 3 cases (1 DIEP flap, 1 TRAM, and 1 PAP flap) and the other 2 cases (pedicled TRAM) needed additional free anastomosis to ensure sufficient blood supply (pedicled TRAM and free TRAM); the other flaps were harvested according to preoperative plan and repaired defect successfully. The mean follow-up was 5 months (range, 1-9 months). The other flaps survived without infection or fat necrosis except 1 PAP flap with distal necrosis. Intraoperative indocyanine green angiography can provide real-time information of flap perfusion and then the operation plan can be adjusted in time to ensure the flap survival.

Efficient flapping flight of pterosaurs

NASA Astrophysics Data System (ADS)

Strang, Karl Axel

In the late eighteenth century, humans discovered the first pterosaur fossil remains and have been fascinated by their existence ever since. Pterosaurs exploited their membrane wings in a sophisticated manner for flight control and propulsion, and were likely the most efficient and effective flyers ever to inhabit our planet. The flapping gait is a complex combination of motions that sustains and propels an animal in the air. Because pterosaurs were so large with wingspans up to eleven meters, if they could have sustained flapping flight, they would have had to achieve high propulsive efficiencies. Identifying the wing motions that contribute the most to propulsive efficiency is key to understanding pterosaur flight, and therefore to shedding light on flapping flight in general and the design of efficient ornithopters. This study is based on published results for a very well-preserved specimen of Coloborhynchus robustus, for which the joints are well-known and thoroughly described in the literature. Simplifying assumptions are made to estimate the characteristics that can not be inferred directly from the fossil remains. For a given animal, maximizing efficiency is equivalent to minimizing power at a given thrust and speed. We therefore aim at finding the flapping gait, that is the joint motions, that minimize the required flapping power. The power is computed from the aerodynamic forces created during a given wing motion. We develop an unsteady three-dimensional code based on the vortex-lattice method, which correlates well with published results for unsteady motions of rectangular wings. In the aerodynamic model, the rigid pterosaur wing is defined by the position of the bones. In the aeroelastic model, we add the flexibility of the bones and of the wing membrane. The nonlinear structural behavior of the membrane is reduced to a linear modal decomposition, assuming small deflections about the reference wing geometry. The reference wing geometry is computed for

[Reconstruction of ankle and foot with combination of free perforator flaps and skin graft].

PubMed

Yin, Lu; Gong, Ketong; Yin, Zhonggang; Zhang, Bo; Xu, Jianhua

2017-03-01

To evaluate the clinical outcomes of free perforator flaps combined with skin graft for reconstruction of ankle and foot soft tissue defects. Between June 2014 and October 2015, 20 cases of ankle and foot soft tissue defects were treated. There were 16 males and 4 females, aged from 19 to 61 years (mean, 43.3 years). Injury was caused by traffic accident in 7 cases, by crashing in 9 cases, and machine twist in 4 cases. The locations were the ankle in 6 cases, the heel in 3 cases, the dorsum pedis in 4 cases, and the plantar forefoot in 7 cases of avulsion injury after toes amputation. The size of wound ranged from 15 cm×10 cm to 27 cm×18 cm. The time from injury to treatment was from 11 to 52 days (mean, 27 days). The anterolateral thigh perforator flap was used in 11 cases, thoracodorsal antery perforator flap in 3 cases, medial sural artery perforator flap in 4 cases, deep inferior epigastric perforator flap in 1 case, and anteromedial thigh perforator flap in 1 case, including 5 chimeric perforator flaps, 5 polyfoliate perforator flaps, 3 flow-through perforator flaps, and 3 conjoined perforator flaps. The size of the perforator flap ranged from 10.0 cm×6.5 cm to 36.0 cm×8.0 cm, the size of skin graft from 5 cm×3 cm to 18 cm×12 cm. Venous crisis occurred in 2 flaps which survived after symptomatic treatment; 18 flaps survived successfully and skin grafting healed well. The follow-up time ranged 4-18 months (mean, 8.3 months). The flaps had good appearance, texture and color, without infection. The patients could walk normally and do daily activities. Only linear scars were observed at the donor sites. Free perforator flap can be used to reconstruct defects in the ankle and foot, especially in the weight-bearing area of the plantar forefoot. A combination of free perforator flap and skin graft is ideal in reconstruction of great soft tissue defects in the ankle and foot.

Keystone-designed buried de-epithelialized flap

PubMed Central

Kim, Hoon; Ryu, Wan Cheol; Yoon, Chi Sun; Kim, Kyu Nam

2017-01-01

Abstract Effective obliteration of dead space after reconstructive surgery facilitates a good cosmetic outcome and prevention of delayed wound healing and recurrent infection. We evaluated the efficacy of a keystone-designed buried de-epithelialized (KBD) flap for the obliteration of small to moderately sized surgical dead spaces. We reviewed the medical records of patients who received a KBD flap following removal of a mass or debridement of necrotic tissue from September 2015 to February 2016. The diagnosis, site, dead space dimensions, flap width, drain data, complications, and follow-up duration were recorded. Twenty-eight KBD flaps were evaluated, including 9 cases of fat necrosis, 7 cases of epidermal cyst, and 12 cases of lipoma. Dead space dimensions ranged from 2 × 1.5 × 1 cm to 10 × 5 × 3 cm, with a mean depth of 2.01 cm. Flap sizes ranged from 2.5 × 1 cm to 11 × 3 cm, with a mean flap width of 2.01 cm. No postoperative complications, such as seroma or hematoma, occurred. The cosmetic results were favorable, and all patients were satisfied with their final outcomes. The KBD flap is useful for the obliteration of small to moderately sized surgical dead spaces both spatially and physiologically and shows excellent cosmetic outcomes. PMID:28538418

Cannula-Assisted Flap Elevation (CAFE): a novel technique for developing flaps during skin-sparing mastectomies.

PubMed

Grant, Michael D

2015-02-01

One of the most challenging procedures in breast surgery is the skin-sparing mastectomy (SSM). Various techniques and incisions have evolved that characterize this procedure; however, what is common in all of them is the smaller the incision, the more difficult it is to develop the skin flaps. A procedure was developed that incorporates the use of liposuction cannulas (without suction) to create the skin flaps. The technique and results are described in this manuscript. From October of 2012 to April 2014, 289 mastectomies (171 patients) were performed using the CAFE procedure on women of all shapes and sizes. Postoperatively, no problems were experienced with flap viability using this technique. The main difference in side effects between the CAFE technique and other standard techniques for developing flaps in SSMs was more bruising than normal, but this resolved rapidly. The results for use of this technique were consistently impressive. The learning curve for this procedure is very short, especially for those who perform SSMs using sharp technique (scissors). Residents and fellows became proficient with the CAFE technique in a relatively short amount of time. Plastic surgeons were pleased with the cosmetic outcomes of their reconstructions that follow this type of mastectomy. Patients were extremely satisfied with their reconstructions as well. Incorporating the use of liposuction cannulas (without suction) makes the creation of flaps for SSM a relatively simple and rapid method. It is especially useful to assist in developing skin flaps with even the smallest of skin incisions.

The role of postoperative hematoma on free flap compromise.

PubMed

Ahmad, Faisal I; Gerecci, Deniz; Gonzalez, Javier D; Peck, Jessica J; Wax, Mark K

2015-08-01

Hematomas may develop in the postoperative setting after free tissue transfer. When hematomas occur, they can exert pressure on surrounding tissues. Their effect on the vascular pedicle of a free flap is unknown. We describe our incidence of hematoma in free flaps and outcomes when the flap is compromised. Retrospective chart review of 1,883 free flaps performed between July 1998 and June 2014 at a tertiary referral center. Patients with free flap compromise due to hematoma were identified. Etiology, demographic data, and outcomes were evaluated. Eighty-eight (4.7%) patients developed hematomas. Twenty (22.7%) of those had flap compromise. Twelve compromises (60%) showed evidence of pedicle thrombosis. The salvage rate was 75% versus 54% in 79 flaps with compromise from other causes (P = .12). Mean time to detection of the hematoma was 35.3 hours in salvaged flaps compared to 91.6 hours in unsalvageable flaps (P = .057). Time to operating room (OR) from detection was 2.8 hours in salvageable flaps compared to 12.4 hours in nonsalvageable flaps (P = .053). The salvage rate for flaps that returned to the OR in <5 hours was 93.3% compared to 20% (P = .0049) for those that did not. Vascular thrombosis reduced salvage rate to 58.3% from 100% (P = .002) when there was no thrombosis. In our series hematomas developed rarely. When they did, 23% went on to develop flap compromise. Prompt recognition and re-exploration allowed for a high salvage rate. Vessel thrombosis predicted inability to salvage the flap. 4 © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

Mandibular reconstruction in irradiated patients utilizing myosseous-cutaneous flaps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pearlman, N.W.; Albin, R.E.; O'Donnell, R.S.

1983-10-01

Myosseous-cutaneous flaps were used for mandibular reconstruction in 16 irradiated patients. Three of six sternomastoid-clavicle flaps failed (all in conjunction with a neck dissection), as did one of 10 pectoralis major-anterior-fifth rib flaps. One trapezius-scapular flap was used and it succeeded. We found the blood supply of the sternomastoid-clavicle flap too tenuous for use in conjunction with a neck dissection. The trapezius-scapular flap had too short an arc of rotation to be used for defects other than those in the horizontal ramus. In addition, this flap required a change of position and created an undesirable functional deformity. The pectoralis major-fifthmore » rib flap, in contrast, could be used for a variety of defects, in conjunction with a neck dissection, and did not require a change of position during operation. We found it to be the most versatile and dependable of the flaps employed in this series.« less

50 CFR Figure 16 to Part 223 - Escape Opening and Flap Dimensions for the Double Cover Flap TED

Code of Federal Regulations, 2014 CFR

2014-10-01

... 50 Wildlife and Fisheries 10 2014-10-01 2014-10-01 false Escape Opening and Flap Dimensions for the Double Cover Flap TED 16 Figure 16 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES... MARINE AND ANADROMOUS SPECIES Pt. 223, Fig. 16 Figure 16 to Part 223—Escape Opening and Flap Dimensions...

50 CFR Figure 16 to Part 223 - Escape Opening and Flap Dimensions for the Double Cover Flap TED

Code of Federal Regulations, 2013 CFR

2013-10-01

... 50 Wildlife and Fisheries 10 2013-10-01 2013-10-01 false Escape Opening and Flap Dimensions for the Double Cover Flap TED 16 Figure 16 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES... MARINE AND ANADROMOUS SPECIES Pt. 223, Fig. 16 Figure 16 to Part 223—Escape Opening and Flap Dimensions...

Pre-expanded Intercostal Perforator Super-Thin Skin Flap.

PubMed

Liao, Yunjun; Luo, Yong; Lu, Feng; Hyakusoku, Hiko; Gao, Jianhua; Jiang, Ping

2017-01-01

This article introduces pre-expanded super-thin intercostal perforator flaps, particularly the flap that has a perforator from the first to second intercostal spaces. The key techniques, advantages and disadvantages, and complications and management of this flap are described. At present, the thinnest possible flap is achieved by thinning the pre-expanded flap that has a perforator from the first to second intercostal spaces. It is used to reconstruct large defects on the face and neck, thus restoring function and cosmetic appearance. Copyright © 2016 Elsevier Inc. All rights reserved.

14 CFR 25.1511 - Flap extended speed.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Flap extended speed. 25.1511 Section 25.1511 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Limitations § 25.1511 Flap extended speed. The established flap extended speed V FE must be established so...

14 CFR 25.1511 - Flap extended speed.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Flap extended speed. 25.1511 Section 25.1511 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Limitations § 25.1511 Flap extended speed. The established flap extended speed V FE must be established so...

14 CFR 25.1511 - Flap extended speed.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flap extended speed. 25.1511 Section 25.1511 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Limitations § 25.1511 Flap extended speed. The established flap extended speed V FE must be established so...

Reconstruction of pressure sores with perforator-based propeller flaps.

PubMed

Jakubietz, Rafael G; Jakubietz, Danni F; Zahn, Robert; Schmidt, Karsten; Meffert, Rainer H; Jakubietz, Michael G

2011-03-01

Perforator flaps have been successfully used for reconstruction of pressure sores. Although V-Y advancement flaps approximate debrided wound edges, perforator-based propeller flaps allow rotation of healthy tissue into the defect. Perforator-based propeller flaps were planned in 13 patients. Seven pressure sores were over the sacrum, five over the ischial tuberosity, and one on the tip of the scapula. Three patients were paraplegic, six were bedridden, and five were ambulatory. In three patients, no perforators were found. In 10 patients, propeller flaps were transferred. In two patients, total flap necrosis occurred, which was reconstructed with local advancement flaps. In two cases, a wound dehiscence occurred and had to be revised. One hematoma required evacuation. No further complications were noted. No recurrence at the flap site occurred. Local perforator flaps allow closure of pressure sores without harvesting muscle. The propeller version has the added benefit of transferring tissue from a distant site, avoiding reapproximation of original wound edges. Twisting of the pedicle may cause torsion and venous obstruction. This can be avoided by dissecting a pedicle of at least 3 cm. Propeller flaps are a safe option for soft tissue reconstruction of pressure sores. © Thieme Medical Publishers.

Reconstruction Using Locoregional Flaps for Large Skull Base Defects.

PubMed

Hatano, Takaharu; Motomura, Hisashi; Ayabe, Shinobu

2015-06-01

We present a modified locoregional flap for the reconstruction of large anterior skull base defects that should be reconstructed with a free flap according to Yano's algorithm. No classification of skull base defects had been proposed for a long time. Yano et al suggested a new classification in 2012. The lb defect of Yano's classification extends horizontally from the cribriform plate to the orbital roof. According to Yano's algorithm for subsequent skull base reconstructive procedures, a lb defect should be reconstructed with a free flap such as an anterolateral thigh free flap or rectus abdominis myocutaneous free flap. However, our modified locoregional flap has also enabled reconstruction of lb defects. In this case series, we used a locoregional flap for lb defects. No major postoperative complications occurred. We present our modified locoregional flap that enables reconstruction of lb defects.

The "chimeric" trapezius muscle and fasciocutaneous flap (dorsal scapular artery perforator flap): a new design for complex 3-dimensional defects.

PubMed

Rozen, Warren M; Fox, Carly M; Leong, James; Morsi, Adel

2013-11-01

Multiple variations of the musculocutaneous trapezius flap have been described, each of which use a single composite musculocutaneous unit in their designs. The limitation of such designs is the ability to use the components in a 3-dimensional manner, with only 1 vector existing in the geometry of the musculocutaneous unit. A review of the literature was undertaken with regard to designs of the musculocutaneous trapezius flap, and we present a new technique for flap design. With identification of individual perforators to each of the muscle and fasciocutaneous portions of the trapezius flap, the 2 components can act in a chimeric fashion, able to fill both a deep and complex 3-dimensional space while covering the wound with robust skin. A range of flap designs have been described, including transverse, oblique, and vertical skin paddles accompanying the trapezius muscle. We describe a technique with which a propeller-style skin paddle based on a cutaneous perforator can be raised in any orientation with respect to the underlying muscle. In a presented case, separation of the muscular and fasciocutaneous components of the trapezius flap was able to obliterate dead space around exposed cervicothoracic spinal metalwork and obtain robust wound closure in a patient with previous radiotherapy. This concomitant use of a muscle and fasciocutaneous perforator flap based on a single perforator, a so-called chimeric perforator flap, is a useful modification to trapezius musculocutaneous flap design.

14 CFR 23.1511 - Flap extended speed.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Flap extended speed. 23.1511 Section 23.1511 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1511 Flap extended speed. (a) The flap extended speed V FE must be established so that it is...

14 CFR 23.1511 - Flap extended speed.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flap extended speed. 23.1511 Section 23.1511 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1511 Flap extended speed. (a) The flap extended speed V FE must be established so that it is...

14 CFR 23.1511 - Flap extended speed.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Flap extended speed. 23.1511 Section 23.1511 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1511 Flap extended speed. (a) The flap extended speed V FE must be established so that it is...

14 CFR 23.1511 - Flap extended speed.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Flap extended speed. 23.1511 Section 23.1511 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1511 Flap extended speed. (a) The flap extended speed V FE must be established so that it is...

14 CFR 23.1511 - Flap extended speed.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flap extended speed. 23.1511 Section 23.1511 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1511 Flap extended speed. (a) The flap extended speed V FE must be established so that it is...

Long-Term Follow-Up of Flap Prefabrication in Facial Reconstruction.

PubMed

Wang, Weixin; Zhao, Muxin; Tang, Yong; Chen, Wen; Yang, Zhe; Ma, Ning; Xu, Lisi; Feng, Jun; Li, Yangqun

2017-07-01

Flap prefabrication is to turn a random flap into an axial flap by transferring a vascular pedicle. In the past 13 years, we have prefabricated 20 flaps in 20 patients by the superficial temporal artery and its concomitant veins. Typically, a 50- to 800-mL tissue expander was implanted in the donor site. After flap maturation, the prefabricated flap was raised and transferred locally to cover the large defect on the face. All the cases were followed up regularly. The patients' age were between 3 and 27 years, the size of the flaps were between 3.5 × 5.5 cm and 13 × 15 cm, the superficial temporal artery length was between 10 and 15 cm. All flaps were transferred successfully: 10 of the flaps had venous congestion, partial epidermis exfoliation and flap necrosis occurred in 4 flaps. All cases were followed up for at least 1 year, the longest follow-up period was 9 years. Long-term follow-up results showed the prefabricated flap survived in good condition and had a satisfactory outcome. Because flap prefabrication is practical, and long-term follow-ups have proved its preferable characters and stability, it is a fine method for large area facial reconstructions.

Aromatic residues located close to the active center are essential for the catalytic reaction of flap endonuclease-1 from hyperthermophilic archaeon Pyrococcus horikoshii.

PubMed

Matsui, Eriko; Abe, Junko; Yokoyama, Hideshi; Matsui, Ikuo

2004-04-16

Flap endonuclease-1 (FEN-1) possessing 5'-flap endonuclease and 5'-->3' exonuclease activity plays important roles in DNA replication and repair. In this study, the kinetic parameters of mutants at highly conserved aromatic residues, Tyr33, Phe35, Phe79, and Phe278-Phe279, in the vicinity of the catalytic centers of FEN-1 were examined. The substitution of these aromatic residues with alanine led to a large reduction in kcat values, although these mutants retained Km values similar to that of the wild-type enzyme. Notably, the kcat of Y33A and F79A decreased 333-fold and 71-fold, respectively, compared with that of the wild-type enzyme. The aromatic residues Tyr33 and Phe79, and the aromatic cluster Phe278-Phe279 mainly contributed to the recognition of the substrates without the 3' projection of the upstream strand (the nick, 5'-recess-end, single-flap, and pseudo-Y substrates) for the both exo- and endo-activities, but played minor roles in recognizing the substrates with the 3' projection (the double flap substrate and the nick substrate with the 3' projection). The replacement of Tyr33, Phe79, and Phe278-Phe279, with non-charged aromatic residues, but not with aliphatic hydrophobic residues, recovered the kcat values almost fully for the substrates without the 3' projection of the upstream strand, suggesting that the aromatic groups of Tyr33, Phe79, and Phe278-Phe279 might be involved in the catalytic reaction, probably via multiple stacking interactions with nucleotide bases. The stacking interactions of Tyr33 and Phe79 might play important roles in fixing the template strand and the downstream strand, respectively, in close proximity to the active center to achieve the productive transient state leading to the hydrolysis.

Comparison of the deep inferior epigastric perforator flap and free transverse rectus abdominis myocutaneous flap in postmastectomy reconstruction: a cost-effectiveness analysis.

PubMed

Thoma, Achilleas; Veltri, Karen; Khuthaila, Dana; Rockwell, Gloria; Duku, Eric

2004-05-01

This study compared the deep inferior epigastric perforator (DIEP) flap and the free transverse rectus abdominis myocutaneous (TRAM) flap in postmastectomy reconstruction using a cost-effectiveness analysis. A decision analytic model was used. Medical costs associated with the two techniques were estimated from the Ontario Ministry of Health Schedule of Benefits for 2002. Hospital costs were obtained from St. Joseph's Healthcare, a university teaching hospital in Hamilton, Ontario, Canada. The utilities of clinically important health states related to breast reconstruction were obtained from 32 "experts" across Canada and converted into quality-adjusted life years. The probabilities of these various clinically important health states being associated with the DIEP and free TRAM flaps were obtained after a thorough review of the literature. The DIEP flap was more costly than the free TRAM flap ($7026.47 versus $6508.29), but it provided more quality-adjusted life years than the free TRAM flap (28.88 years versus 28.53 years). The baseline incremental cost-utility ratio was $1464.30 per quality-adjusted life year, favoring adoption of the DIEP flap. Sensitivity analyses were performed by assuming that the probabilities of occurrence of hernia, abdominal bulging, total flap loss, operating room time, and hospital stay were identical with the DIEP and free TRAM techniques. By assuming that the probability of postoperative hernia for the DIEP flap increased from 0.008 to 0.054 (same as for TRAM flap), the incremental cost-utility ratio changed to $1435.00 per quality-adjusted life year. A sensitivity analysis was performed for the complication of hernia because the DIEP flap allegedly diminishes this complication. Increasing the probability of abdominal bulge from 0.041 to 0.103 for the DIEP flap changed the ratio to $2731.78 per quality-adjusted life year. When the probability of total flap failure was increased from 0.014 to 0.016, the ratio changed to $1384.01 per

A computer program to calculate the longitudinal aerodynamic characteristics of wing-flap configurations with externally blown flaps

NASA Technical Reports Server (NTRS)

Mendenhall, M. R.; Goodwin, F. K.; Spangler, S. B.

1976-01-01

A vortex lattice lifting-surface method is used to model the wing and multiple flaps. Each lifting surface may be of arbitrary planform having camber and twist, and the multiple-slotted trailing-edge flap system may consist of up to ten flaps with different spans and deflection angles. The engine wakes model consists of a series of closely spaced vortex rings with circular or elliptic cross sections. The rings are normal to a wake centerline which is free to move vertically and laterally to accommodate the local flow field beneath the wing and flaps. The two potential flow models are used in an iterative fashion to calculate the wing-flap loading distribution including the influence of the waves from up to two turbofan engines on the semispan. The method is limited to the condition where the flow and geometry of the configurations are symmetric about the vertical plane containing the wing root chord. The calculation procedure starts with arbitrarily positioned wake centerlines and the iterative calculation continues until the total configuration loading converges within a prescribed tolerance. Program results include total configuration forces and moments, individual lifting-surface load distributions, including pressure distributions, individual flap hinge moments, and flow field calculation at arbitrary field points.

Lift production through asymmetric flapping

NASA Astrophysics Data System (ADS)

Jalikop, Shreyas; Sreenivas, K. R.

2009-11-01

At present, there is a strong interest in developing Micro Air Vehicles (MAV) for applications like disaster management and aerial surveys. At these small length scales, the flight of insects and small birds suggests that unsteady aerodynamics of flapping wings can offer many advantages over fixed wing flight, such as hovering-flight, high maneuverability and high lift at large angles of attack. Various lift generating mechanims such as delayed stall, wake capture and wing rotation contribute towards our understanding of insect flight. We address the effect of asymmetric flapping of wings on lift production. By visualising the flow around a pair of rectangular wings flapping in a water tank and numerically computing the flow using a discrete vortex method, we demonstrate that net lift can be produced by introducing an asymmetry in the upstroke-to-downstroke velocity profile of the flapping wings. The competition between generation of upstroke and downstroke tip vortices appears to hold the key to understanding this lift generation mechanism.

Scalp Free Flap Reconstruction Using Anterolateral Thigh Flap Pedicle for Interposition Artery and Vein Grafts

PubMed Central

Park, Jun Hyung; Eun, Suk Chan; Lee, Jong Hoon; Hong, Sung Hee; Kim, Chin Whan

2012-01-01

We experienced satisfactory outcomes by synchronously transplanting an artery and vein using an anterolateral thigh flap pedicle between the vascular pedicle and recipient vessel of a flap for scalp reconstruction. A 45-year-old man developed a subdural hemorrhage due to a fall injury. In this patient, the right temporal cranium was missing and the patient had 4×3 cm and 6×5 cm scalp defects. We planned a scalp reconstruction using a latissimus dorsi free flap. Intraoperatively, there was a severe injury to the right superficial temporal vessel because of previous neurosurgical operations. A 15 cm long pedicle defect was needed to reach the recipient facial vessels. For the vascular graft, the descending branch of the lateral circumflex femoral artery and two venae comitantes were harvested. The flap survived well and the skin graft was successful with no notable complications. When an interposition graft is needed in the reconstruction of the head and neck region for which mobility is mandatory to a greater extent, a sufficient length of graft from an anterolateral flap pedicle could easily be harvested. Thus, this could contribute to not only resolving the disadvantages of a venous graft but also to successfully performing a vascular anastomosis. PMID:22783493

Reconstruction of Anterolateral Thigh Defects Using Perforator-Based Propeller Flaps.

PubMed

Iida, Takuya; Yoshimatsu, Hidehiko; Koshima, Isao

2017-10-01

Usually, anterolateral thigh (ALT) defects with width more than 8 cm cannot be closed directly. Although several methods of using local flaps exist, flap mobility of these methods is limited. We introduced a perforator-based propeller flap for such reconstruction. Their maximal mobility, which minimizes their size, is their greatest advantage. In addition, we present our technical refinements including double-axes propeller flap, the use of indocyanine green real-time angiography, and supercharged propeller flap for safer flap transfer. Seven patients underwent perforator-based propeller flap reconstruction of ALT defects. Flaps were designed cranial or caudal to the defect according to the perforator locations. To maximize mobility, flaps were designed so that the perforator was located at the periphery and closer to the defect. After rotating the flap to the defect, indocyanine green angiography was performed to determine the need for supercharge. In all cases, all flaps survived completely. Defect size ranged from 12 × 11 cm to 18 × 16 cm, and flap size ranged from 7 × 5 cm to 15 × 7 cm. The number of perforators in the flap was 1 in 3 cases and 2 in 4 cases. Supercharging was performed in 3 cases. Donor-site complications, including gait disturbance, were not observed. This method achieves ALT defect closure with minimal donor-site morbidity and can provide prompt and aesthetically acceptable results. Indocyanine green real-time angiography and supercharging technique are also useful for safer and reliable flap transfer.

Flow field of flexible flapping wings

NASA Astrophysics Data System (ADS)

Sallstrom, Erik

The agility and maneuverability of natural fliers would be desirable to incorporate into engineered micro air vehicles (MAVs). However, there is still much for engineers to learn about flapping flight in order to understand how such vehicles can be built for efficient flying. The goal of this study is to develop a methodology for capturing high quality flow field data around flexible flapping wings in a hover environment and to interpret it to gain a better understanding of how aerodynamic forces are generated. The flow field data was captured using particle image velocimetry (PIV) and required that measurements be taken around a repeatable flapping motion to obtain phase-averaged data that could be studied throughout the flapping cycle. Therefore, the study includes the development of flapping devices with a simple repeatable single degree of freedom flapping motion. The acquired flow field data has been examined qualitatively and quantitatively to investigate the mechanisms behind force production in hovering flight and to relate it to observations in previous research. Specifically, the flow fields have been investigated around a rigid wing and several carbon fiber reinforced flexible membrane wings. Throughout the whole study the wings were actuated with either a sinusoidal or a semi-linear flapping motion. The semi-linear flapping motion holds the commanded angular velocity nearly constant through half of each half-stroke while the sinusoidal motion is always either accelerating or decelerating. The flow fields were investigated by examining vorticity and vortex structures, using the Q criterion as the definition for the latter, in two and three dimensions. The measurements were combined with wing deflection measurements to demonstrate some of the key links in how the fluid-structure interactions generated aerodynamic forces. The flow fields were also used to calculate the forces generated by the flapping wings using momentum balance methods which yielded

Combined application of latissimus dorsi myocutaneous flap and iliac bone flap in the treatment of chronic osteomyelitis of the lower extremity.

PubMed

Ju, Jihui; Li, Lei; Zhou, Rong; Hou, Ruixing

2018-05-18

To evaluate the clinical efficacy and safety of latissimus dorsi myocutaneous flap (stage I) combined with iliac bone flap (stage II) in the treatment of chronic osteomyelitis of the lower extremity. Clinical data of 18 patients undergoing latissimus dorsi myocutaneous flap in combination with iliac bone flap grafting were retrospectively analyzed. Among them, 2 patients developed chronic osteomyelitis of the lower segment of the femur, 4 were diagnosed with chronic osteomyelitis of the tibial plateau, and 12 with chronic osteomyelitis of the lower segment of the tibia. All the latissimus dorsi myocutaneous flaps survived in 18 patients. After the corresponding surgery, primary wound healing was achieved in 11 patients, and delayed wound healing was obtained in 7 cases. All wounds were completely healed with postoperative 2 months. Following the iliac bone flap grafting, primary would healing was accomplished in all cases. All dorsal window chambers survived. The bone defects were properly restored within 4-12 postoperative months. Functional training was performed after removal of the internal and external fixators. Postoperative follow-up was endured from 6 months to 10 years. All patients were satisfied with the bone healing and flap texture without the incidence of osteomyelitis and sinus tract. No contraction was observed in the grafting area of 2 patients receiving latissimus dorsi myocutaneous flap grafting. Residual linear scars were noted in the dorsal and iliac donor sites. Combined usage of stage I latissimus dorsi myocutaneous flap and stage II iliac bone flap grafting is an efficacious and safe surgical technique in clinical practice.

A Simple Strategy in Avulsion Flap Injury: Prediction of Flap Viability Using Wood's Lamp Illumination and Resurfacing with a Full-thickness Skin Graft.

PubMed

Lim, Hyoseob; Han, Dae Hee; Lee, Il Jae; Park, Myong Chul

2014-03-01

Extensive degloving injuries of the extremities usually result in necrosis of the flap, necessitating comprehensive skin grafting. Provided there is a sufficient tool to evaluate flap viability, full-thickness skin can be used from a nonviable avulsed flap. We used a Wood's lamp to determine the viability of avulsed flaps in the operation field after intravenous injection of fluorescein dye. We experienced 13 cases during 16 months. Fifteen minutes after the intravenous injection of fluorescein dye, the avulsed skin flaps were examined and non-fluorescent areas were marked under Wood's lamp illumination. The marked area was defatted for full-thickness skin grafting. The fluorescent areas were sutured directly without tension. The non-fluorescent areas were covered by defatted skin. Several days later, there was soft tissue necrosis within the flap area. We measured necrotic area and revised the flap. Among all the cases, necrotic area was 21.3% of the total avulsed area. However, if we exclude three cases, one of a carelessly managed patient and two cases of the flaps were inappropriately applied, good results were obtained, with a necrotic area of only 8.4%. Eight patients needed split-thickness skin grafts, and heel pad reconstruction was performed with free flap. A full-thickness skin graft from an avulsed flap is a good method for addressing aesthetic concerns without producing donor site morbidity. Fluorescein dye is a useful, simple, and cost-effective tool for evaluating flap viability. Avulsed flap injuries can be managed well with Wood's lamp illumination and a full-thickness skin graft.

[DORSALIS PEDIS FLAP SERIES-PARALLEL BIG TOE NAIL COMPOSITE TISSUE FLAP TO REPAIR HAND SKIN OF DEGLOVING INJURY WITH THUMB DEFECT].

PubMed

Shi, Pengju; Zhang, Wenlong; Zhao, Gang; Li, Zhigang; Zhao, Shaoping; Zhang, Tieshan

2015-07-01

To investigate the effectiveness of dorsalis pedis flap series-parallel big toe nail composite tissue flap in the repairment of hand skin of degloving injury with tumb defect. Between March 2009 and June 2013, 8 cases of hand degloving injury with thumb defect caused by machine twisting were treated. There were 7 males and 1 female with the mean age of 36 years (range, 26-48 years). Injury located at the left hand in 3 cases and at the right hand in 5 cases. The time from injury to hospitalization was 1.5-4.0 hours (mean, 2.5 hours). The defect area was 8 cm x 6 cm to 15 cm x 1 cm. The thumb defect was rated as degree I in 5 cases and as degree II in 3 cases. The contralateral dorsal skin flap (9 cm x 7 cm to 10 cm x 8 cm) combined with ipsilateral big toe nail composite tissue flap (2.5 cm x 1.8 cm to 3.0 cm x 2.0 cm) was used, including 3 parallel anastomosis flaps and 5 series anastomosis flaps. The donor site of the dorsal flap was repaired with thick skin grafts, the stumps wound was covered with tongue flap at the shank side of big toe. Vascular crisis occurred in 1 big toe nail composite tissue flap, margin necrosis occurred in 2 dorsalis pedis flap; the other flaps survived, and primary healing of wound was obtained. The grafted skin at dorsal donor site all survived, skin of hallux toe stump had no necrosis. Eight cases were followed up 4-20 months (mean, 15.5 months). All flaps had soft texture and satisfactory appearance; the cutaneous sensory recovery time was 4-7 months (mean, 5 months). At 4 months after operation, the two-point discrimination of the thumb pulp was 8-10 mm (mean, 9 mm), and the two-point discrimination of dorsal skin flap was 7-9 mm (mean, 8.5 mm). According to Society of Hand Surgery standard for the evaluation of upper part of the function, the results were excellent in 4 cases, good in 3 cases, and fair in 1 case. The donor foot had normal function. Dorsalis pedis flap series-parallel big toe nail composite tissue flap is an ideal

Repair of nostril stenosis using a triple flap combination: boomerang, nasolabial, and vestibular rotation flaps.

PubMed

Bozkurt, Mehmet; Kapi, Emin; Kuvat, Samet Vasfi; Selçuk, Caferi Tayyar

2012-11-01

Tissue losses within the nose due to various reasons result in the loss of normal anatomy and function. The external nasal valve area is one of the most important functional components of the nose. The columella, lobule, nostril, and alar region are among the components forming the external nasal valve area. Deformities of the nostrils are among the most frequently observed features that interfere with the functional anatomy of the nose. Malformations of the nostrils often emerge subsequent to cleft lip repairs. Stenoses are a common type of pathology among nostril deformities. In cases where a stenosis has formed, breathing problems and developmental anomalies may occur. In the patient with nostril stenosis presented in this report, there was a serious alar collapse and contracture subsequent to a cleft lip repair. In order to repair the nostril stenosis, a "boomerang flap" was chosen. This boomerang flap was used in combination with a nasolabial flap, a vestibular rotation flap, and a conchal cartilage graft to achieve a satisfactory repair.

Triple flap technique for vulvar reconstruction.

PubMed

Mercut, R; Sinna, R; Vaucher, R; Giroux, P A; Assaf, N; Lari, A; Dast, S

2018-04-09

Perineal defects are encountered ever more frequently, in the treatment of vulvar cancers or abdominoperineal resection. The surgical treatment of vulvar cancer leads to significant skin defect. The aim of the reconstruction is not to provide volume but rather to resurface perineum. We propose a new solution to cover the extensive skin defect remaining after excision. We report 3 patients who underwent large excision for vulvar cancer, with lymph node dissection. For reconstruction, we performed 3 advancement flaps. Two V-Y flaps cantered on the infra-gluteal folds and based on pudendal perforator arteries were used to cover the postero-lateral parts of the defect. The third advancement flap from the superior aspect of the defect was a Y-V Mons pubis flap. The defects were successfully covered by the 3 flap technique. The first patient suffered a non-union that slowly healed by secondary intention. For the other cases, we used the same technique, but applied negative pressure wound therapy on the sutures, with excellent results. The 3 flap technique is a simple and reliable method and the donor site morbidity is minimal. It can be realised without changing the position of the patient after tumour excision, and does not require delicate perforator dissection. This surgical option can be easily applied, allowing better management of these cases. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

"Internet of Things" Real-Time Free Flap Monitoring.

PubMed

Kim, Sang Hun; Shin, Ho Seong; Lee, Sang Hwan

2018-01-01

Free flaps are a common treatment option for head and neck reconstruction in plastic reconstructive surgery, and monitoring of the free flap is the most important factor for flap survival. In this study, the authors performed real-time free flap monitoring based on an implanted Doppler system and "internet of things" (IoT)/wireless Wi-Fi, which is a convenient, accurate, and efficient approach for surgeons to monitor a free flap. Implanted Doppler signals were checked continuously until the patient was discharged by the surgeon and residents using their own cellular phone or personal computer. If the surgeon decided that a revision procedure or exploration was required, the authors checked the consumed time (positive signal-to-operating room time) from the first notification when the flap's status was questioned to the determination for revision surgery according to a chart review. To compare the efficacy of real-time monitoring, the authors paired the same number of free flaps performed by the same surgeon and monitored the flaps using conventional methods such as a physical examination. The total survival rate was greater in the real-time monitoring group (94.7% versus 89.5%). The average time for the real-time monitoring group was shorter than that for the conventional group (65 minutes versus 86 minutes). Based on this study, real-time free flap monitoring using IoT technology is a method that surgeon and reconstruction team can monitor simultaneously at any time in any situation.

Pressure Available for Cooling with Cowling Flaps

NASA Technical Reports Server (NTRS)

Stickle, George W; Naiman, Irven; Crigler, John L

1941-01-01

Report presents the results of a full-scale investigation conducted in the NACA 20-foot tunnel to determine the pressure difference available for cooling with cowling flaps. The flaps were applied to an exit slot of smooth contour at 0 degree flap angle. Flap angles of 0 degree, 15 degrees, and 30 degrees were tested. Two propellers were used; propeller c which has conventional round blade shanks and propeller f which has airfoil sections extending closer to the hub. The pressure available for cooling is shown to be a direct function of the thrust disk-loading coefficient of the propeller.

Flap Edge Noise Reduction Fins

NASA Technical Reports Server (NTRS)

Khorrami, Mehdi R. (Inventor); Choudhan, Meelan M. (Inventor)

2015-01-01

A flap of the type that is movably connected to an aircraft wing to provide control of an aircraft in flight includes opposite ends, wherein at least a first opposite end includes a plurality of substantially rigid, laterally extending protrusions that are spaced apart to form a plurality of fluidly interconnected passageways. The passageways have openings adjacent to upper and lower sides of the flap, and the passageways include a plurality of bends such that high pressure fluid flows from a high pressure region to a low pressure region to provide a boundary condition that inhibits noise resulting from airflow around the end of the flap.

Coarse-grained models for interacting, flapping swimmers

NASA Astrophysics Data System (ADS)

Oza, Anand; Ristroph, Leif; Shelley, Michael; Courant Institute Applied Math Lab Collaboration

2016-11-01

We present the results of a theoretical investigation into the dynamics of interacting flapping swimmers. Our study is motivated by ongoing experiments in the NYU Applied Math Lab, in which freely-translating, heaving airfoils interact hydrodynamically to choose their relative positions and velocities. We develop a discrete dynamical system in which flapping swimmers shed point vortices during each flapping cycle, which in turn exert forces on the swimmers. We present a framework for finding exact solutions to the evolution equations and for assessing their stability, giving physical insight into the preference for certain observed "schooling states". The model may be extended to arrays of flapping swimmers, and configurations in which the swimmers' flapping frequencies are incommensurate. Generally, our results indicate how hydrodynamics may mediate schooling and flocking behavior in biological contexts. A. Oza acknowledges the support of the NSF Mathematical Sciences Postdoctoral Fellowship.

Flap Edge Aeroacoustic Measurements and Predictions

NASA Technical Reports Server (NTRS)

Brooks, Thomas F.; Humphreys, William M., Jr.

2000-01-01

An aeroacoustic model test has been conducted to investigate the mechanisms of sound generation on high-lift wing configurations. This paper presents an analysis of flap side-edge noise, which is often the most dominant source. A model of a main element wing section with a half-span flap was tested at low speeds of up to a Mach number of 0.17, corresponding to a wing chord Reynolds number of approximately 1.7 million. Results are presented for flat (or blunt), flanged, and round flap-edge geometries, with and without boundary-layer tripping, deployed at both moderate and high flap angles. The acoustic database is obtained from a Small Aperture Directional Array (SADA) of microphones, which was constructed to electronically steer to different regions of the model and to obtain farfield noise spectra and directivity from these regions. The basic flap-edge aerodynamics is established by static surface pressure data, as well as by Computational Fluid Dynamics (CFD) calculations and simplified edge flow analyses. Distributions of unsteady pressure sensors over the flap allow the noise source regions to be defined and quantified via cross-spectral diagnostics using the SADA output. It is found that shear layer instability and related pressure scatter is the primary noise mechanism. For the flat edge flap, two noise prediction methods based on unsteady surface pressure measurements are evaluated and compared to measured noise. One is a new causality spectral approach developed here. The other is a new application of an edge-noise scatter prediction method. The good comparisons for both approaches suggest that much of the physics is captured by the prediction models. Areas of disagreement appear to reveal when the assumed edge noise mechanism does not fully define the noise production. For the different edge conditions, extensive spectra and directivity are presented. Significantly, for each edge configuration, the spectra for different flow speeds, flap angles, and

Flap Edge Aeroacoustic Measurements and Predictions

NASA Technical Reports Server (NTRS)

Brooks, Thomas F.; Humphreys, William M., Jr.

2000-01-01

An aeroacoustic model test has been conducted to investigate the mechanisms of sound generation on high-lift wing configurations. This paper presents an analysis of flap side-edge noise, which is often the most dominant source. A model of a main element wing section with a half-span flap was tested at low speeds of up to a Mach number of 0.17, corresponding to a wing chord Reynolds number of approximately 1.7 million. Results are presented for flat (or blunt), flanged, and round flap-edge geometries, with and without boundary-layer tripping, deployed at both moderate and high flap angles. The acoustic database is obtained from a Small Aperture Directional Array (SADA) of microphones, which was constructed to electronically steer to different regions of the model and to obtain farfield noise spectra and directivity from these regions. The basic flap-edge aerodynamics is established by static surface pressure data, as well as by Computational Fluid Dynamics (CFD) calculations and simplified edge flow analyses. Distributions of unsteady pressure sensors over the flap allow the noise source regions to be defined and quantified via cross-spectral diagnostics using the SADA output. It is found that shear layer instability and related pressure scatter is the primary noise mechanism. For the flat edge flap, two noise prediction methods based on unsteady-surface-pressure measurements are evaluated and compared to measured noise. One is a new causality spectral approach developed here. The other is a new application of an edge-noise scatter prediction method. The good comparisons for both approaches suggest that much of the physics is captured by the prediction models. Areas of disagreement appear to reveal when the assumed edge noise mechanism does not fully define, the noise production. For the different edge conditions, extensive spectra and directivity are presented. Significantly, for each edge configuration, the spectra for different flow speeds, flap angles, and

Early wound healing of laser in situ keratomileusis-like flaps after treatment with human corneal stromal stem cells.

PubMed

Morgan, Siân R; Dooley, Erin P; Kamma-Lorger, Christina; Funderburgh, James L; Funderburgh, Martha L; Meek, Keith M

2016-02-01

To use a well-established organ culture model to investigate the effects of corneal stromal stem cells on the optical and biomechanical properties of corneal wounds after laser in situ keratomileusis (LASIK)-like flap creation. School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom. Experimental study. The LASIK-like flaps were produced in sheep corneas. The flap beds were treated with corneal stromal stem cells and were then replaced and allowed to heal for different periods of up to 3 weeks in organ culture. The optical transmission of the cornea, the force required to detach the flap, and the presence of myofibroblasts near the flap bed were measured. Corneal stromal stem cell-treated flap beds were statistically significantly more transparent after 3 weeks in culture than the untreated controls. At 3 weeks, the mean force necessary to detach the flap was more than twice the force required for the respective control samples. Concurrently, there were 44% activated cells immediately below the flap margin of the controls compared with 29% in the same region of the corneal stromal stem cell-treated flaps. In this system, the presence of corneal stromal stem cells at the wound margin significantly increased the adherence of LASIK-like flaps while maintaining corneal transparency. It is postulated that this is achieved by the deposition of extracellular connective tissue similar to that found in the normal cornea and by the paucity of activated keratocytes (myofibroblasts), which are known to scatter a significant amount of the incident light. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Proteome analysis reveals that de novo regenerated mucosa over fibula flap-reconstructed mandibles resembles mature keratinized oral mucosa.

PubMed

Kumar, Vinay V; James, Bonney L; Ruß, Manuela; Mikkat, Stefan; Suresh, Amritha; Kämmerer, Peer W; Glocker, Michael O

2018-03-01

The aim of this study was to determine whether intra-oral de novo regenerated mucosa (D) that grew over free fibula flap reconstructed-mandibles resembled the donor tissue i.e. external skin (S) of the lateral leg, or the recipient site tissue, i.e. keratinized oral mucosa (K). Differential proteome analysis was performed with ten tissue samples from each of the three groups: de novo regenerated mucosa (D), external skin (S), and keratinized oral mucosa (K). Expression differences of cornulin and involucrin were validated by Western blot analysis and their spatial distributions in the respective tissues were ascertained by immunohistochemistry. From all three investigated tissue types a total of 1188 proteins were identified, 930 of which were reproducibly and robustly quantified by proteome analysis. The best differentiating proteins were assembled in an oral mucosa proteome signature that encompasses 56 differentially expressed proteins. Principal component analysis of both, the 930 quantifiable proteins and the 56 oral mucosa signature proteins revealed that the de novo regenerated mucosa resembles keratinized oral mucosa much closer than extra-oral skin. Differentially expressed cornification-related proteins comprise proteins from all subclasses of the cornified cell envelope. Prominently expressed in intra-oral mucosa tissues were (i) cornifin-A, cornifin-B, SPRR3, and involucrin from the cornified-cell-envelope precursor group, (ii) S100A9, S100A8 and S100A2 from the S100 group, and (iii) cornulin which belongs to the fused-gene-protein group. According to its proteome signature de novo regenerated mucosa over the free fibula flap not only presents a passive structural surface layer but has adopted active tissue function. Copyright © 2018 Elsevier Ltd. All rights reserved.

Classification and Microvascular Flap Selection for Anterior Cranial Fossa Reconstruction.

PubMed

Vargo, James D; Przylecki, Wojciech; Camarata, Paul J; Andrews, Brian T

2018-05-18

 Microvascular reconstruction of the anterior cranial fossa (ACF) creates difficult challenges. Reconstructive goals and flap selection vary based on the defect location within the ACF. This study evaluates the feasibility and reliability of free tissue transfer for salvage reconstruction of low, middle, and high ACF defects.  A retrospective review was performed. Reconstructions were anatomically classified as low (anterior skull base), middle (frontal bar/sinus), and high (frontal bone/soft tissue). Subjects were evaluated based on pathologic indication and goal, type of flap used, and complications observed.  Eleven flaps in 10 subjects were identified and anatomic sites included: low ( n  = 5), middle ( n  = 3), and high ( n  = 3). Eight of 11 reconstructions utilized osteocutaneous flaps including the osteocutaneous radial forearm free flap (OCRFFF) ( n  = 7) and fibula ( n  = 1). Other reconstructions included a split calvarial graft wrapped within a temporoparietal fascia free flap ( n  = 1), latissimus myocutaneous flap ( n  = 1), and rectus abdominis myofascial flap ( n  = 1). All 11 flaps were successful without microvascular compromise. No complications were observed in the high and middle ACF defect groups. Two of five flaps in the low defect group using OCRFFF flaps failed to achieve surgical goals despite demonstrating healthy flaps upon re-exploration. Complications included persistent cerebrospinal fluid leak ( n  = 1) and pneumocephalus ( n  = 1), requiring flap repositioning in one subject and a second microvascular flap in the second subject to achieve surgical goals.  In our experience, osteocutaneous flaps (especially the OCRFFF) are preferred for complete autologous reconstruction of high and middle ACF defects. Low skull base defects are more difficult to reconstruct, and consideration of free muscle flaps (no bone) should be weighed as an option in this anatomic area. Thieme Medical Publishers

Temporalis myo-osseous flap: an experimental study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antonyshyn, O.; Colcleugh, R.G.; Hurst, L.N.

1986-03-01

The present paper investigates the anatomy and vascularization of the temporalis myo-osseous flap. This is a calvarial bone flap that employs temporalis muscle and its distal pericranial extension as a pedicle. In six human cadavers the flap was raised as an island on the anterior deep temporal artery after transecting the zygomatic arch and coronoid process. Maximal mobilization was thus obtained, allowing rotation of the flap into the mouth for intraoral reconstruction. The arc of rotation and potential surgical applications were noted. A comparative study of the temporalis myo-osseous flap and free calvarial bone graft was then conducted in amore » rabbit model. Vascularization of the calvarial bone flap was confirmed by technetium scintigraphy performed on the first postoperative day. The uptake of fluorochrome labels immediately after transfer verified the adequacy of the periosteal circulation in maintaining viability and new osteoid formation throughout the full thickness of calvarial bone. The transplantation of free calvarial bone grafts was followed by necrosis of most cellular elements. This was demonstrated by an absence of fluorochrome uptake up to 19 days postoperatively and a predominance of empty lacunae and nonviable marrow.« less

The clinical application of anterolateral thigh flap.

PubMed

Lee, Yao-Chou; Chiu, Haw-Yen; Shieh, Shyh-Jou

2011-01-01

The anterolateral thigh flap can provide a large skin paddle nourished by a long and large-caliber pedicle and can be harvested by two-team work. Most importantly, the donor-site morbidity is minimal. However, the anatomic variations decreased its popularity. By adapting free-style flap concepts, such as preoperative mapping of the perforators and being familiar with retrograde perforator dissection, this disadvantage had been overcome gradually. Furthermore, several modifications widen its clinical applications: the fascia lata can be included for sling or tendon reconstruction, the bulkiness could be created by including vastus lateralis muscle or deepithelization of skin flap, the pliability could be increased by suprafascial dissection or primary thinning, the pedicle length could be lengthening by proximally eccentric placement of the perforator, and so forth. Combined with these technical and conceptual advancements, the anterolateral thigh flap has become the workhorse flap for soft-tissue reconstructions from head to toe.

REAR DETAIL OF RIGHT ENGINE AND WING. FLAPS REMAIN DOWN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

REAR DETAIL OF RIGHT ENGINE AND WING. FLAPS REMAIN DOWN AND SPOILERS UP. THIS CONFIGURATION IS AUTOMATICALLY ACTIVATED ON ROLLOUT. - Greater Buffalo International Airport, Maintenance Hangar, Buffalo, Erie County, NY

Reconstruction of eyelids with Washio flap in anophthalmia.

PubMed

Tvrdek, M; Kozák, J

2014-01-01

The authors present a case report of a patient with anophthalmia in whom retroauriculo-temporal flap (Washio flap) was used for reconstruction of eyelids. This flap, which is mostly used for reconstructions of nasal defects, was not used in this way according to available literature.

Pectoralis myocutaneous flap for salvage of necrotic wounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Price, J.C.; Davis, R.K.; Koltai, P.J.

1985-02-01

The authors have utilized six pectoralis major myocutaneous flaps in attempts to salvage extensive necrotic wounds of the pharynx and neck. The flap was employed in the following situations: massive necrosis of the entire neck skin with both carotid artery systems exposed, radiation necrosis of the neck skin with exposure of carotid artery, dehiscence of gastric pull-up from pharynx with resultant carotid exposure, failed trapezius flap in a radionecrotic oral cavity, and two cases of pharyngocutaneous fistula with extensive soft tissue necrosis. These flaps achieved healing in all cases. One death occurred 3 weeks following complete cutaneous healing secondary tomore » a ruptured carotid pseudoaneurysm. One flap underwent total skin loss but the entirety of the muscle survived and the fistula was successfully closed with the back of the muscle being subsequently skin grafted. One case of dehiscence of the flap from oral mucosa resulted in a minor exposure of mandible with limited osteoradionecrosis controlled by topical means. This flap has performed extremely well in these precarious and difficult situations that previously may not have been salvageable. It has also been effective in abbreviating the required hospitalization and wound care. The authors conclude that the pectoralis myocutaneous flap should be the primary choice for the management of extensive postsurgical wound necrosis.« less

Calf Perforator Flaps: A Freestyle Solution for Oral Cavity Reconstruction.

PubMed

Molina, Alexandra R; Citron, Isabelle; Chinaka, Fungayi; Cascarini, Luke; Townley, William A

2017-02-01

Reconstruction of oral cavity defects requires a thin, pliable flap for optimal functional results. Traditional flap choices are imperfect: the anterolateral thigh flap is excessively thick, whereas the radial forearm flap has a poor donor site. The authors therefore favor calf perforator flaps such as the medial sural artery perforator flap to provide thin tissue with an acceptable donor site. This two-part study aims to demonstrate their suitability for intraoral reconstruction. In the radiologic part of the study, the authors compared thigh and calf tissue thickness by examining lower limb computed tomographic scans of 100 legs. For their clinical study, they collected data prospectively on 20 cases of oral cavity reconstruction using calf perforator flaps. The mean thickness of the calf tissue envelope was significantly less than that of the thigh (8.4 mm compared with 17 mm) based on computed tomographic analysis. In the clinical study, a medial sural artery perforator was used in the majority of cases (17 of 20). The mean pedicle length was 10.2 cm and the mean time to raise a flap was 85 minutes. There were no flap losses. One patient was returned to the operating room for management of late hematoma and wound dehiscence. Calf perforator flaps provide ideal tissue for intraoral reconstruction and are significantly thinner than anterolateral thigh flaps. In addition to medial sural artery perforator flaps, the authors raised both sural and soleal artery perforator flaps in this series. Opportunistic use of the calf donor site allows the harvest of thin tissue with minimal donor-site morbidity. Therapeutic, IV.

New method for maximum mobilization of temporalis muscle flap.

PubMed

Masic, Tarik; Babajic, Emina; Dervisevic, Almir; Hassouba, Mahmoud

2012-01-01

Pedicled temporalis muscle flap presenting a good flap for closing large craniofacial defects. Careful surgeons usually do not mobilize temporalis muscle flap enough to make appropriate use, fully closure, especially if defect exceeds the median line. Temporalis flap was used in 16 patients, ages ranged between 12 and 76. In all cases defect reconstruction was done by useing new method of extending standard temporal muscle flap. During surgical procedure it is very important to keep periosteal elevator in close contact with the bone. Then, there is no risk for pedicle injury. After vascular pedicle is identified elevating temporal muscle has to be continued by releasing the muscle insertion from the coronoid process. By this way, flap length and arc of rotation is increased. The flap remained viable in all instances. Most of the patients experienced no perioperative complications. There was no major complications or mortality as a result of performed procedures. With this division, flap length was increased at least 2 cm wich is enough for covering defects crossing the midline. Instead of using bilateral temporalis muscle flaps for defect closure, unilateral is sufficient. With this extension of the pedicle length now rotation point is not at the level of the zygomatic arch but lower part mandibular neck.

Flexible wings in flapping flight

NASA Astrophysics Data System (ADS)

Moret, Lionel; Thiria, Benjamin; Zhang, Jun

2007-11-01

We study the effect of passive pitching and flexible deflection of wings on the forward flapping flight. The wings are flapped vertically in water and are allowed to move freely horizontally. The forward speed is chosen by the flapping wing itself by balance of drag and thrust. We show, that by allowing the wing to passively pitch or by adding a flexible extension at its trailing edge, the forward speed is significantly increased. Detailed measurements of wing deflection and passive pitching, together with flow visualization, are used to explain our observations. The advantage of having a wing with finite rigidity/flexibility is discussed as we compare the current results with our biological inspirations such as birds and fish.

Application of multidetector-row computed tomography in propeller flap planning.

PubMed

Ono, Shimpei; Chung, Kevin C; Hayashi, Hiromitsu; Ogawa, Rei; Takami, Yoshihiro; Hyakusoku, Hiko

2011-02-01

The propeller flap is defined as (1) being island-shaped, (2) having an axis that includes the perforators, and (3) having the ability to be rotated around an axis. The advantage of the propeller flap is that it is a pedicle flap that can be applied to cover defects located at the distal ends of the extremities. The specific aims of the authors' study were (1) to evaluate the usefulness of multidetector-row computed tomography in the planning of propeller flaps and (2) to present a clinical case series of propeller flap reconstructions that were planned preoperatively using multidetector-row computed tomography. The authors retrospectively analyzed all cases between April of 2007 and April of 2010 at Nippon Medical School Hospital in Tokyo, where multidetector-row computed tomography was used preoperatively to plan surgical reconstructions using propeller flaps. Thirteen patients underwent 16 flaps using the propeller flap technique. The perforators were identified accurately by multidetector-row computed tomography preoperatively in all cases. This is the first report describing the application of multidetector-row computed tomography in the planning of propeller flaps. Multidetector-row computed tomography is superior to other imaging methods because it demonstrates more precisely the perforator's position and subcutaneous course using high-resolution three-dimensional images. By using multidetector-row computed tomography to preoperatively identify a flap's perforators, the surgeon can better plan the flap design to efficiently conduct the flap surgery.

A performance application study of a jet-flap helicopter rotor

NASA Technical Reports Server (NTRS)

Sullivan, R. J.; Laforge, S.; Holchin, B. W.

1972-01-01

A performance study was made of the application of a jet-flap to a reaction-drive rotor for a heavy-lift helicopter mission and for a high-speed-helicopter maneuverability (200 knots, 2g) mission. The results of the study are as follows: As a result of the increase in maximum airfoil lift coefficient achieved by the jet-flap, rotor solidity is reduced with the jet-flap to approximately 59% of a nonjet-flap rotor. As a result of the saving in rotor solidity, and hence in rotor weight, the jet-flap configuration had a 21% higher productivity than a nonjet-flap configuration. Of the three propulsion systems studied utilizing a jet-flap (hot cycle, warm cycle, cold cycle) the hot cycle gave the largest increase in productivity. The 200 knot 2g mission is performed best with a warm cycle propulsion system. The jet-flap permits designing for a rotor blade loading coefficient C sub T/sigma = .170 at 2g without encountering blade stall. The jet-flap rotor permits a 200 knot 2g maneuver without suffering the penalty of an unreasonable rotor solidity that would be required by a nonjet-flap rotor.

Comparison of 5468 retreatments after laser in situ keratomileusis by lifting the flap or performing photorefractive keratectomy on the flap.

PubMed

Ortega-Usobiaga, J; Llovet-Osuna, F; Katz, T; Djodeyre, M R; Druchkiv, V; Bilbao-Calabuig, R; Baviera, J

2018-02-01

To assess visual outcomes of retreatment after laser in situ keratomileusis (LASIK) by lifting the flap or performing photorefractive keratectomy (PRK) on the flap, as well as to establish whether there was an increased risk of epithelial ingrowth (EIG) when LASIK and lifting of the flap are separated by a long time interval and to determine the incidence of corneal haze after PRK. Retrospective study of 4077 patients (5468 eyes) who underwent LASIK and subsequent retreatment were reviewed in order to study their visual results and identify cases of EIG and corneal haze. Enhancements included 5196 eyes from 3876 patients that were retreated by lifting the flap, and 272 eyes from 201 patients that were retreated by PRK on the flap. No statistically significant differences were found between the retreatments in terms of predictability, efficacy, and safety. A total of 704 cases of EIG were found after lifting the flap, for which surgical cleansing was necessary in 70. Surgical cleansing decreased the efficacy index when compared with patients with EIG who did not need cleansing (P=.01). Differences in terms of safety and predictability were not statistically significant. The incidence of corneal haze after ablation of the surface of the previous flap was 14.34%, although none of these cases were clinically relevant. Visual outcomes were similar between patients who were retreated by lifting the flap and those who underwent PRK. The incidence of EIG when the flap was lifted was 13.55%. The incidence of EIG increases with the time elapsed between the primary procedure and retreatment. Copyright © 2017 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

The Clinical Application of Anterolateral Thigh Flap

PubMed Central

Lee, Yao-Chou; Chiu, Haw-Yen; Shieh, Shyh-Jou

2011-01-01

The anterolateral thigh flap can provide a large skin paddle nourished by a long and large-caliber pedicle and can be harvested by two-team work. Most importantly, the donor-site morbidity is minimal. However, the anatomic variations decreased its popularity. By adapting free-style flap concepts, such as preoperative mapping of the perforators and being familiar with retrograde perforator dissection, this disadvantage had been overcome gradually. Furthermore, several modifications widen its clinical applications: the fascia lata can be included for sling or tendon reconstruction, the bulkiness could be created by including vastus lateralis muscle or deepithelization of skin flap, the pliability could be increased by suprafascial dissection or primary thinning, the pedicle length could be lengthening by proximally eccentric placement of the perforator, and so forth. Combined with these technical and conceptual advancements, the anterolateral thigh flap has become the workhorse flap for soft-tissue reconstructions from head to toe. PMID:22567234

Defining the Role of Free Flaps in Partial Breast Reconstruction.

PubMed

Smith, Mark L; Molina, Bianca J; Dayan, Erez; Jablonka, Eric M; Okwali, Michelle; Kim, Julie N; Dayan, Joseph H

2018-03-01

 Free flaps have a well-established role in breast reconstruction after mastectomy; however, their role in partial breast reconstruction remains poorly defined. We reviewed our experience with partial breast reconstruction to better understand indications for free tissue transfer.  A retrospective review was performed of all patients undergoing partial breast reconstruction at our center between February 2009 and October 2015. We evaluated the characteristics of patients who underwent volume displacement procedures versus volume replacement procedures and free versus pedicled flap reconstruction.  There were 78 partial breast reconstructions, with 52 reductions/tissue rearrangements (displacement group) and 26 flaps (replacement group). Bra cup size and body mass index (BMI) were significantly smaller in the replacement group. Fifteen pedicled and 11 free flaps were performed. Most pedicled flaps (80.0%) were used for lateral or upper pole defects. Most free flaps (72.7%) were used for medial and inferior defects or when there was inadequate donor tissue for a pedicled flap. Complications included hematoma, cellulitis, and one aborted pedicled flap.  Free and pedicled flaps are useful for partial breast reconstruction, particularly in breast cancer patients with small breasts undergoing breast-conserving treatment (BCT). Flap selection depends on defect size, location, and donor tissue availability. Medial defects are difficult to reconstruct using pedicled flaps due to arc of rotation and intervening breast tissue. Free tissue transfer can overcome these obstacles. Confirming negative margins before flap reconstruction ensures harvest of adequate volume and avoids later re-operation. Judicious use of free flaps for oncoplastic reconstruction expands the possibility for breast conservation. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Propeller Perforator Flaps in Distal Lower Leg: Evolution and Clinical Applications

PubMed Central

2012-01-01

Simple or complex defects in the lower leg, and especially in its distal third, continue to be a challenging task for reconstructive surgeons. A variety of flaps were used in the attempt to achieve excellence in form and function. After a long evolution of the reconstructive methods, including random pattern flaps, axial pattern flaps, musculocutaneous flaps and fasciocutaneous flaps, the reappraisal of the works of Manchot and Salmon by Taylor and Palmer opened the era of perforator flaps. This era began in 1989, when Koshima and Soeda, and separately Kroll and Rosenfield described the first applications of such flaps. Perforator flaps, whether free or pedicled, gained a high popularity due to their main advantages: decreasing donor-site morbidity and improving aesthetic outcome. The use as local perforator flaps in lower leg was possible due to a better understanding of the cutaneous circulation, leg vascular anatomy, angiosome and perforasome concepts, as well as innovations in flaps design. This review will describe the evolution, anatomy, flap design, and technique of the main distally pedicled propeller perforator flaps used in the reconstruction of defects in the distal third of the lower leg and foot. PMID:22783507

Effect of marking pens on femtosecond laser-assisted flap creation.

PubMed

Ide, Takeshi; Kymionis, George D; Abbey, Ashkan M; Yoo, Sonia H; Culbertson, William W; O'Brien, Terrence P

2009-06-01

To compare the ease of the flap lift after central corneal marking with 2 types of marking pens after femtosecond laser-assisted flap creation in laser in situ keratomileusis. Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA. Porcine eyes were prepared for flap creation with a femtosecond laser (IntraLase). The eyes were assigned to 1 of 4 groups. After the femtosecond laser treatment, the difficulty of flap lifting the 4 groups was compared. Twelve porcine eyes, 3 in each group, were evaluated. In the 2 groups in which an oil-based pen was used, the corneal flap could not be lifted. In the 2 groups in which a water-based pen was used, the corneal flap was easily lifted. Oil-based ink may reduce the ability of the femtosecond laser to penetrate the cornea. The resultant corneal flap may require aggressive manipulation to be lifted. When used to mark the center of the cornea before flap creation, water-based ink provided greater ease of corneal flap lifting than oil-based ink. Because the marking is located over the center of the pupil, any alteration of the cornea in this area from aggressive flap lifting may result in substantial visual loss. Therefore, the use of an oil-based ink to mark the central cornea must be avoided to prevent traumatic irregularities of the flap stroma.

Double transverse myocutaneous gracilis free flaps for unilateral breast reconstruction.

PubMed

Werdin, Frank; Haug, Daniel M; Amr, Amro; Schoeller, Thomas

2016-10-01

In cases were the deep inferior epigastric perforator flap (DIEP flap) is not available and unilateral transverse myocutaneous gracilis flap (TMG flap) is not sufficient for breast reconstruction, we perform double TMG flaps as a reconstructive method. In this report, we present our results of the use of double TMG free-flap-transfer for unilateral breast reconstruction. Between August 2004 and June 2012 we performed 58 TMG flaps in 29 patients for unilateral breast reconstruction. Patient data were analyzed and operative outcome (operation time, complication rate and aesthetic results) were investigated. Aesthetic outcome was evaluated retrospectively via photo documentation by an independent plastic surgeon. The results were classified in;unsatisfactory, satisfactory, good and very good. The average operating time was 6 hours 55 minutes (295 - 650 minutes). Of 58 TMG flaps, 57 (98.3%) were successful. Thrombosis occurred in seven (12%) cases (1 arterial, 6 venous). Flap salvage was successful in six cases and flap failure occurred in one (1.7%) case. The results of 25 patients were graded as good and very good. Three patients showed satisfying and one patient unsatisfying results. Double TMG flaps in unilateral breast reconstruction could lead to good operative results. This method further expands the range of options with autologous tissue in reconstructive breast surgery. © 2015 Wiley Periodicals, Inc. Microsurgery 36:539-545, 2016. © 2015 Wiley Periodicals, Inc.

Damping in flapping flight and its implications for manoeuvring, scaling and evolution.

PubMed

Hedrick, Tyson L

2011-12-15

Flying animals exhibit remarkable degrees of both stability and manoeuvrability. Our understanding of these capabilities has recently been improved by the identification of a source of passive damping specific to flapping flight. Examining how this damping effect scales among different species and how it affects active manoeuvres as well as recovery from perturbations provides general insights into the flight of insects, birds and bats. These new damping models offer a means to predict manoeuvrability and stability for a wide variety of flying animals using prior reports of the morphology and flapping motions of these species. Furthermore, the presence of passive damping is likely to have facilitated the evolution of powered flight in animals by providing a stability benefit associated with flapping.

Flap-edge aeroacoustic measurements and predictions

NASA Astrophysics Data System (ADS)

Brooks, Thomas F.; Humphreys, William M.

2003-03-01

An aeroacoustic model test has been conducted to investigate the mechanisms of sound generation on high-lift wing configurations. This paper presents an analysis of flap side-edge noise, which is often the most dominant source. A model of a main element wing section with a half-span flap was tested at low speeds of up to a Mach number of 0.17, corresponding to a wing chord Reynolds number of approximately 1.7 million. Results are presented for flat (or blunt), flanged, and round flap-edge geometries, with and without boundary-layer tripping, deployed at both moderate and high flap angles. The acoustic database is obtained from a small aperture directional array (SADA) of microphones, which was constructed to electronically steer to different regions of the model and to obtain farfield noise spectra and directivity from these regions. The basic flap-edge aerodynamics is established by static surface pressure data, as well as by computational fluid dynamics (CFD) calculations and simplified edge flow analyses. Distributions of unsteady pressure sensors over the flap allow the noise source regions to be defined and quantified via cross-spectral diagnostics using the SADA output. It is found that shear layer instability and related pressure scatter is the primary noise mechanism. For the flat edge flap, two noise prediction methods based on unsteady-surface-pressure measurements are evaluated and compared to measured noise. One is a new causality spectral approach developed here. The other is a new application of an edge-noise scatter prediction method. The good comparisons for both approaches suggest that the prediction models capture much of the physics. Areas of disagreement appear to reveal when the assumed edge noise mechanism does not fully define the noise production. For the different edge conditions, extensive spectra and directivity are presented. The complexity of the directivity results demonstrate the strong role of edge source geometry and frequency in

Accuracy of Visual Estimation of LASIK Flap Thickness.

PubMed

Brenner, Jason E; Fadlallah, Ali; Hatch, Kathryn M; Choi, Catherine; Sayegh, Rony R; Kouyoumjian, Paul; Wu, Simon; Frangieh, George T; Melki, Samir A

2017-11-01

To assess the accuracy of surgeons' visual estimation of LASIK flap thickness when created by a femtosecond laser by comparing it to ultrasound measurements. Surgeons were asked to visually estimate the thickness of a femtosecond flap during the procedure. Total corneal thickness was measured by ultrasound pachymetry prior to the procedure and the stromal bed was similarly measured after flap lifting. The estimates from three experienced surgeons (cornea fellowship trained and more than 5 years in practice) were compared to those of three cornea fellows, with each surgeon evaluating 20 eyes (120 total). Surgeons were not told the thickness of the flaps unless required for safety reasons. The average difference between visual and ultrasonic estimation of LASIK flap thickness was 15.20 μm. The flap was 10 μm thicker than estimated in 37% of eyes, 20 μm thicker in 17% of eyes, and 30 μm thicker in 10% of eyes. The largest deviation was 53 μm. There was no statistically significant difference between the accuracy of experienced surgeons and fellows (P = .51). There are significant differences between surgeons' visual estimates and ultrasonic measurements of LASIK flap thickness. Relying on these visual estimates may lead to deeper excimer laser ablation than intended. This could lead to thinner residual stromal beds and higher percent tissue altered than planned. The authors recommend that surgeons measure flaps intraoperatively to maximize accuracy and safety. [J Refract Surg. 2017;33(11):765-767.]. Copyright 2017, SLACK Incorporated.

[Analysis of sequelae of the latissimus dorsi flap removal. Report of 44 cases reviewed and tested].

PubMed

Legré, R; Boghossian, V; Servant, J M; Magalon, G; Bureau, H

1990-01-01

Since Tanzini, the latissimus dorsi muscle flap has been widely used in plastic surgery. Based on the experience of two plastic surgery units, we decided to try to define the sequelae of this operation. In order to simplify our analysis we only considered free flaps. Out study is based on 42 patients (26 pure muscular flaps and 16 musculo-cutaneous flaps). The sequelae were analysed in terms of aesthetic and functional criteria. The aesthetic sequelae appeared to be minima in the case of pure muscular flaps, but more severe in the case of musculo-cutaneous flaps. Functional sequelae in the shoulder were observed on muscle testing in 30% of cases, although there were no repercussions on sport or work activities. Analysis of spinal posture demonstrated a modification in the frontal plane in 40% of cases although this could not be clearly attributed to the donor site. On the basis of this study, we can conclude that the latissimus dorsi flap retains an important place in the therapeutic arsenal of plastic surgery due to its reliability and its minor cicatricial and functional sequelae at the donor site.

[The repair of bulky tissue defect of forearm with skin flaps].

PubMed

Huang, Xiaoyuan; Long, Jianhong; Xie, Tinghong; Zhang, Minghua; Zhang, Pihong; Yang, Xinghua; Zhong, Keqin

2002-12-01

To evaluate the repairing methods of bulky tissue defect of forearm with flaps. Twenty-one burned patients with wounds in the forearm were enrolled in this study. The injury causes were high-voltage electricity, hot press or crush injury. After local debridement, the forearm defects were repaired with pedicled complex flaps, latissimus dorsi musculocutaneous island flaps or large thoraco-abdominal flaps immediately. All the flaps survived very well with satisfactory results except for 1 patient in whom local ischemic necrosis and sub-flap infection at the distal end of the flap occurred. Early debridement followed by skin flaps with pedicles or musculocutaneous flaps transfer could be simple, safe and reliable treatment strategies in the management of bulky tissue defects of the forearm due to burn, electric injury, or other devastating injuries.

The Anterior Interosseus Artery Perforator Flap: Anatomical Dissections and Clinical Study.

PubMed

Panse, Nikhil S; Joshi, Sheetal B; Sahasrabudhe, Parag B; Bahetee, B; Gurude, Pradnya; Chandanwale, Ajay

2017-05-01

Reconstruction of upper extremity deformities continues to be a challenge to the reconstructive surgeon. Various loco regional, distant and free flaps are available for reconstruction. However, each has its own set of advantages and disadvantages. Of the commonly performed local flaps, radial artery forearm flap, and the posterior interosseus artery flap stand out prominently. Recently, perforator propeller flaps have been used for resurfacing the upper extremity. The anterior interosseus artery perforator flap is an uncommonly used and described flap. This study was divided into anatomical study and clinical application in a IV level of evidence. In the anatomical study, five upper extremities were studied. Clinically, 12 patients underwent reconstruction using the anterior interosseus artery perforator flap. Flaps were performed by a single surgeon. A retrospective review of these cases from November 2008 to May 2014 is presented. The anterior interosseus artery perforator was identified in four out of five cadaver limbs. The septocutaneous perforator was in the fifth extensor compartment around 4 cm proximal to the wrist joint. Of the twelve flaps, there was complete necrosis in one flap, and partial necrosis in one flap. The patient with complete necrosis underwent skin grafting at a later date. The wound healed secondarily in case of partial flap necrosis. Anterior interosseus artery perforator flap must be considered as an important reconstructive option in the armamentarium of the plastic surgeon, while managing hand and wrist defects.

The Anterior Interosseus Artery Perforator Flap: Anatomical Dissections and Clinical Study

PubMed Central

Panse, Nikhil S; Joshi, Sheetal B; Sahasrabudhe, Parag B; Bahetee, B; Gurude, Pradnya; Chandanwale, Ajay

2017-01-01

BACKGROUND Reconstruction of upper extremity deformities continues to be a challenge to the reconstructive surgeon. Various loco regional, distant and free flaps are available for reconstruction. However, each has its own set of advantages and disadvantages. Of the commonly performed local flaps, radial artery forearm flap, and the posterior interosseus artery flap stand out prominently. Recently, perforator propeller flaps have been used for resurfacing the upper extremity. The anterior interosseus artery perforator flap is an uncommonly used and described flap. METHODS This study was divided into anatomical study and clinical application in a IV level of evidence. In the anatomical study, five upper extremities were studied. Clinically, 12 patients underwent reconstruction using the anterior interosseus artery perforator flap. Flaps were performed by a single surgeon. A retrospective review of these cases from November 2008 to May 2014 is presented. RESULTS The anterior interosseus artery perforator was identified in four out of five cadaver limbs. The septocutaneous perforator was in the fifth extensor compartment around 4 cm proximal to the wrist joint. Of the twelve flaps, there was complete necrosis in one flap, and partial necrosis in one flap. The patient with complete necrosis underwent skin grafting at a later date. The wound healed secondarily in case of partial flap necrosis. CONCLUSION Anterior interosseus artery perforator flap must be considered as an important reconstructive option in the armamentarium of the plastic surgeon, while managing hand and wrist defects. PMID:28713704

Binding of Single Walled Carbon Nanotube to WT and Mutant HIV-1 Proteases: Analysis of Flap Dynamics and Binding Mechanism

PubMed Central

Meher, Biswa Ranjan; Wang, Yixuan

2012-01-01

Most of the currently treated HIV-1 protease (HIV-PR) inhibitors have been prone to suffer from the mutations associated drug resistance. Therefore, it is necessary to search for potent alternatives against the drug resistance. In the current study we have tested the single-walled carbon nanotube (SWCNT) as an inhibitor in wild type (WT) as well as in three primary mutants (I50VPR, V82APR and I84VPR) of the HIV-1-PR through docking the SWCNT in the active site region, and then performed all-atom MD simulations for the complexes. The conformational dynamics of HIV-PR with a 20 ns trajectory reveals that the SWCNT can effectively bind to the HIV-1-PR active site and regulate the flap dynamics such as maintaining the flap-flap closed. To gain an insight into the binding affinity, we also performed the MM-PBSA based binding free energy calculations for the four HIV-PR/SWCNT complexes. It was observed that, although the binding between the SWCNT and the HIV-PR decreases due to the mutations, the SWCNTs bind to the HIV-PRs 3–5 folds stronger than the most potent HIV-1-PR inhibitor, TMC114. Remarkably, the significant interactions with binding energy higher than 1 kcal/mol focus on the flap and active regions, which favors closing flap-flap and deactivating the active residues of the HIV-PR. The flap dynamics and binding strength information for HIV-PR and SWCNTs can help design SWCNT-based HIV-1-PR inhibitors. PMID:23142620

Routine closure of the donor site with a second dorsal metacarpal artery flap to avoid the use of a skin graft after harvest of a first dorsal metacarpal artery flap.

PubMed

Chi, Zhenglin; Lin, Damu; Chen, Yiheng; Xue, Jixin; Li, Shi; Chu, Tinggang; Li, Zhijie

2018-06-01

Closure of the donor site on the index finger after raising a first dorsal metacarpal artery (DMA) flap harvest is challenging. The conventional choice is to use a full-thickness skin graft. However, this procedure is associated with several complications and a second donor site to harvest the skin graft is inevitable. The aim of this study was to design a modified incision to allow harvest of a first DMA flap without skin graft. From 2015 to 2016, 18 patients with a soft tissue defect of the thumb had reconstruction of the defect using a first DMA flap. A modified incision was used and a relaying perforator flap pedicled on the second DMA was raised through the same incision to cover the donor site. Patient satisfaction, appearance of the injured hand, and the active range of motion (ROM) were assessed. The sensitivity was evaluated by the 2-point discrimination (2-PD) test. All flaps survived completely without complications. Good coverage was obtained with only one linear scar in the dorsum of the hand and no skin grafts. All patients recovered full range of movement in their fingers and regained sensitivity of the flaps. All patients were satisfied with their hand function according to the Michigan Hand Outcomes Questionnaire (MHQ). The mean cosmetic score for the appearance of the injured hand was 8.2 out of 10. Using our modified incision, it was possible to harvest a second DMA flap at the same time as a first DMA flap allowing simultaneous coverage of the donor defect on the index finger. This prevented the need for a skin graft with all of the associated disadvantages. Copyright © 2018. Published by Elsevier Ltd.

Folding in and out: passive morphing in flapping wings.

PubMed

Stowers, Amanda K; Lentink, David

2015-03-25

We present a new mechanism for passive wing morphing of flapping wings inspired by bat and bird wing morphology. The mechanism consists of an unactuated hand wing connected to the arm wing with a wrist joint. Flapping motion generates centrifugal accelerations in the hand wing, forcing it to unfold passively. Using a robotic model in hover, we made kinematic measurements of unfolding kinematics as functions of the non-dimensional wingspan fold ratio (2-2.5) and flapping frequency (5-17 Hz) using stereo high-speed cameras. We find that the wings unfold passively within one to two flaps and remain unfolded with only small amplitude oscillations. To better understand the passive dynamics, we constructed a computer model of the unfolding process based on rigid body dynamics, contact models, and aerodynamic correlations. This model predicts the measured passive unfolding within about one flap and shows that unfolding is driven by centrifugal acceleration induced by flapping. The simulations also predict that relative unfolding time only weakly depends on flapping frequency and can be reduced to less than half a wingbeat by increasing flapping amplitude. Subsequent dimensional analysis shows that the time required to unfold passively is of the same order of magnitude as the flapping period. This suggests that centrifugal acceleration can drive passive unfolding within approximately one wingbeat in small and large wings. Finally, we show experimentally that passive unfolding wings can withstand impact with a branch, by first folding and then unfolding passively. This mechanism enables flapping robots to squeeze through clutter without sophisticated control. Passive unfolding also provides a new avenue in morphing wing design that makes future flapping morphing wings possibly more energy efficient and light-weight. Simultaneously these results point to possible inertia driven, and therefore metabolically efficient, control strategies in bats and birds to morph or recover

The perforator pedicled propeller (PPP) flap method: report of two cases.

PubMed

Hyakusoku, Hiko; Ogawa, Rei; Oki, Koichiro; Ishii, Nobuaki

2007-10-01

Perforator flaps are thin free-tissue transfers consisting of skin and subcutaneous tissue which have the advantage of decreasing donor site morbidity. We have reconstructed postburn scar contractures using "propeller flaps" of the remaining healthy skin around the recipient sites. In this paper, we report on two cases and describe the concept of using "perforator flaps" and "propeller flaps" together as what are called "perforator pedicled propeller (PPP) flaps." Patient 1 was an 18-year-old man with a sacral pressure ulcer. The soft tissue defect was reconstructed with a rotated superior gluteal artery PPP flap. Patient 2 was a 53-year-old woman who presented with an open fracture of the right elbow. The skin defect over the fracture was covered with a rotated deep brachial artery PPP flap raised on the lateral upper arm. The PPP flaps are useful for burn reconstruction and repairing various types of wound. Moreover, microsurgery is unnecessary. The PPP flap may be classified into two types: the central axis type and the acentric axis type. The central axis PPP flap is significant when used as a 90-degree-rotation island flap, and the acentric axis PPP flap is significant when used as a 180-degree-rotation island flap. Both types are easy to harvest and useful for repairing various kinds of wound.

Abdominal morbidity after single- versus double-pedicled deep inferior epigastric perforator flap use.

PubMed

Uda, Hirokazu; Tomioka, Yoko Katsuragi; Sarukawa, Syunji; Sunaga, Ataru; Kamochi, Hideaki; Sugawara, Yasusih; Yoshimura, Kotaro

2016-09-01

The reduced incidence of donor site morbidity after deep inferior epigastric perforator (DIEP) flap is because the rectus muscle and its fascia are preserved. However, no study has proved that trunk flexion recovers not by the compensatory effect of the contralateral rectus muscle but by reinnervation of the ipsilateral rectus muscle. We hypothesized that if sufficient reinnervation occurs, patients who undergo single-pedicled DIEP (S-DIEP) flap or double-pedicled DIEP (D-DIEP) flap breast reconstruction would have similar levels of preoperative trunk flexion. To determine this, we investigated perioperative changes in trunk flexor muscle ability quantitatively using an isokinetic dynamometer in patients who had received S-DIEP or D-DIEP. Patients who underwent breast reconstruction with S-DIEP (n = 37) and D-DIEP (n = 30) were included in this study. Pre- and postoperative trunk flexor muscle ability was measured prospectively by an isokinetic dynamometer in all patients. Postoperative abdominal pain and stiffness, patients' activity, and incidence of bulging were also investigated. Six months after surgery, the trunk flexor muscle ability recovered and did not significantly decrease subsequently in either group. This finding was consistent with the result that patients' activities and the incidence of bulging were similar between the two groups. Our results show that reinnervation of the rectus muscle can be confirmed at 6 months after DIEP flap elevation. Thus, we recommend D-DIEP flap without concern for abdominal wall weakness, especially in patients with multiple abdominal scars and who require breast tissue exceeding the amount of tissue that can be transferred with S-DIEP flap. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Is It Possible to Increase Flap Viability by Hydrostatic Dilation?: An Experimental Study in the Rat Abdominal Fasciocutaneous Flap Model.

PubMed

Sahin, Cihan; Aysal, Bilge Kagan; Ergun, Ozge

2016-08-01

Ergun et al previously demonstrated the efficacy of hydrostatic dilation in a TRAM flap model in an experimental study. We investigated the effect of hydrostatic dilation on a fasciocutaneous flap model. Eighteen female Wistar rats were equally divided into 3 groups, of which 1 served as a control. In the second, the abdominal fasciocutaneous flap surgical delay procedure was performed by division of the left superficial inferior epigastric (SIE) vessels. In the third, hydrostatic dilation was performed on the left SIE artery and vein, with a mean pressure of 300 mm Hg, while elevating the flap on the right-sided SIE pedicle. The groups were compared by microangiography and by the survival ratio of abdominal flaps 7 days after elevation. The mean (SD) flap necrosis rates were as follows: control group, 44.75% (4.31%); delay group, 33.32% (7.11%); and hydrostatic dilation group, 32.51% (5.03%). There was a significant difference between the control group and the other 2 groups (P < 0.05). There was no difference between the delay and hydrostatic dilation groups with respect to surface area necrosis. The microangiographies showed remarkable increased vascularity in the delay and hydrostatic dilation groups. Hydrostatic dilation is a new method of enhancing flap viability that could be used in clinical cases in place of surgical delay once further studies and clinical trials are completed.

Boomerang flap reconstruction for the breast.

PubMed

Baumholtz, Michael A; Al-Shunnar, Buthainah M; Dabb, Richard W

2002-07-01

The boomerang-shaped latissimus dorsi musculocutaneous flap for breast reconstruction offers a stable platform for breast reconstruction. It allows for maximal aesthetic results with minimal complications. The authors describe a skin paddle to obtain a larger volume than either the traditional elliptical skin paddle or the extended latissimus flap. There are three specific advantages to the boomerang design: large volume, conical shape (often lacking in the traditional skin paddle), and an acceptable donor scar. Thirty-eight flaps were performed. No reconstruction interfered with patient's ongoing oncological regimen. The most common complication was seroma, which is consistent with other latissimus reconstructions.

Neodymium:yttrium-aluminum-garnet laser fusion of endarterectomy flaps.

PubMed

Humphrey, P W; Slocum, M M; Loy, T S; Silver, D

1995-07-01

This study evaluated the efficacy of neodymium:yttrium-aluminum-garnet laser welding of flaps in canine arteries and in securing the distal flap during human carotid endarterectomy. Endarterectomy flaps were created in both common carotid and both common femoral arteries in 12 dogs. The flaps were repaired with either the neodymium:yttrium-aluminum-garnet laser or with 6-0 polypropylene sutures. The arteries were removed after duplex scanning at either 7 or 28 days. Eighteen high carotid endarterectomy flaps in 16 patients have been subsequently secured with the laser welding technique. Laser repairs (125 +/- 19 joule) of the canine arteries were completed more quickly than suture repairs (mean 25 seconds vs 135 seconds, respectively; p < 0.04). Duplex ultrasonography revealed no discernable differences between the two groups of arteries. Arteries studied at 7 days revealed three microscopic flaps (two suture, one laser), more subintimal fibroblastic proliferation in suture than laser-repaired carotid arteries (3: 1, p = 0.0530), and similar amounts of inflammation in suture- and laser-repaired arteries. Arteries studied at 28 days revealed one microscopic intimal flap (suture-repaired); equal fibroblastic and inflammatory responses in suture- and laser-repaired vessels; and no evidence of laser thermal injury. Eighteen carotid endarterectomy flaps have been successfully fused with no immediate or long-term complications in 16 patients (follow-up of 0 to 24 months). Laser fusion appears to be a safe and effective method for securing distal carotid endarterectomy flaps.

[Ablation on the undersurface of a LASIK flap. Instrument and method for continuous eye tracking].

PubMed

Taneri, S; Azar, D T

2007-02-01

The risk of iatrogenic keratectasia after laser in situ keratomileusis (LASIK) increases with thinner posterior stromal beds. Ablations on the undersurface of a LASIK flap could only be performed without the guidance of an eye tracker, which may lead to decentration. A new method for laser ablation with flying spot lasers on the undersurface of a LASIK flap was developed that enables the use of an active eye tracker by utilizing a novel instrument. The first clinical results are reported. Patients wishing an enhancement procedure were eligible for a modified repeat LASIK procedure if the flaps cut in the initial procedure were thick enough to perform the intended additional ablation on the undersurface leaving at least 90 microm of flap thickness behind. (1) The horizontal axis and the center of the entrance pupil were marked on the epithelial side of the flap using gentian violet dye. (2) The flap was reflected on a newly designed flap holder which had a donut-shaped black marking. (3) The eye tracker was centered on the mark visible in transparency on the flap. (4) Ablation with a flying spot Bausch & Lomb Technolas 217z laser was performed on the undersurface of the flap with a superior hinge taking into account that in astigmatic ablations the cylinder axis had to be mirrored according to the formula: axis on the undersurface=180 degrees -axis on the stromal bed. (5) The flap was repositioned. Detection of the marking on the modified flap holder and continuous tracking instead of the real pupil was possible in all of the 12 eyes treated with this technique. It may be necessary to cover the real pupil during ablation in order not to confuse the eye tracker. Ablation could be performed without decentration or loss of best spectacle-corrected visual acuity. Refractive results in minor corrections were good without nomogram adjustment. Using this novel flap holder with a marking that is tracked instead of the real pupil, centered ablations with a flying spot laser

An aeroelastic instability provides a possible basis for the transition from gliding to flapping flight.

PubMed

Curet, Oscar M; Swartz, Sharon M; Breuer, Kenneth S

2013-03-06

The morphology, kinematics and stiffness properties of lifting surfaces play a key role in the aerodynamic performance of vertebrate flight. These surfaces, as a result of their flexible nature, may move both actively, owing to muscle contraction, and passively, in reaction to fluid forces. However, the nature and implications of this fluid-structure interaction are not well understood. Here, we study passive flight (flight with no active wing actuation) and explore a physical mechanism that leads to the emergence of a natural flapping motion. We model a vertebrate wing with a compliant shoulder and the ability to camber with an idealized physical model consisting of a cantilevered flat plate with a hinged trailing flap. We find that at low wind speed the wing is stationary, but at a critical speed the wing spontaneously flaps. The lift coefficient is significantly enhanced once the wing starts to oscillate, although this increase in lift generation is accompanied by an increase in drag. Flow visualization suggests that a strong leading edge vortex attached to the wing during downstroke is the primary mechanism responsible for the enhanced lift. The flapping instability we observe suggests a possible scenario for an evolutionary transition from gliding to powered flapping flight in animals that possess compliant wings capable of passive camber. Although the flapping state is accompanied by a lower lift-to-drag ratio, the increased lifting capability it confers might have enabled increased body mass, improved foraging performance and/or flight at lower speeds, any of which might have been selectively advantageous.

An aeroelastic instability provides a possible basis for the transition from gliding to flapping flight

PubMed Central

Curet, Oscar M.; Swartz, Sharon M.; Breuer, Kenneth S.

2013-01-01

The morphology, kinematics and stiffness properties of lifting surfaces play a key role in the aerodynamic performance of vertebrate flight. These surfaces, as a result of their flexible nature, may move both actively, owing to muscle contraction, and passively, in reaction to fluid forces. However, the nature and implications of this fluid–structure interaction are not well understood. Here, we study passive flight (flight with no active wing actuation) and explore a physical mechanism that leads to the emergence of a natural flapping motion. We model a vertebrate wing with a compliant shoulder and the ability to camber with an idealized physical model consisting of a cantilevered flat plate with a hinged trailing flap. We find that at low wind speed the wing is stationary, but at a critical speed the wing spontaneously flaps. The lift coefficient is significantly enhanced once the wing starts to oscillate, although this increase in lift generation is accompanied by an increase in drag. Flow visualization suggests that a strong leading edge vortex attached to the wing during downstroke is the primary mechanism responsible for the enhanced lift. The flapping instability we observe suggests a possible scenario for an evolutionary transition from gliding to powered flapping flight in animals that possess compliant wings capable of passive camber. Although the flapping state is accompanied by a lower lift-to-drag ratio, the increased lifting capability it confers might have enabled increased body mass, improved foraging performance and/or flight at lower speeds, any of which might have been selectively advantageous. PMID:23303221

Use of the pericranial flap in medial canthal reconstruction: another application for this versatile flap.

PubMed

Leatherbarrow, Brian; Watson, Adam; Wilcsek, Geoffrey

2006-01-01

To describe the use and outcomes of a versatile surgical technique in the reconstruction of deep soft tissue and bony defects of the medial canthus. A retrospective review of consecutive cases requiring reconstruction of medial canthal defects involving loss of periosteum or bone by a median forehead pericranial flap and full-thickness skin grafting in a tertiary referral hospital setting. Two techniques were used: an open technique, using a midline forehead incision; and an endoscopic technique, using 2 incisions behind the hairline. Twenty-one cases were identified: 19 open and 2 endoscopic. The average length of follow-up was 13 months (range, 6-50 months). Ten cases required additional oculoplastic procedures including local periosteal flaps and mucous membrane grafts. Two cases (10%) had complete flap failure; one of these was caused by infection. Five (24%) had partial (< 50%) skin graft necrosis. Two cases (10%) have required further surgery. Our experience shows the pericranial flap to be versatile, robust, and easy to manipulate, offering advantages over alternative techniques when used for the repair of deep medial canthal defects. It is a valuable reconstructive technique that can yield good cosmetic and functional results.

[Repair of pressure sores over ischial tuberosity with long head of biceps femoris muscle flap combined with semi-V posterior thigh fasciocutaneous flap].

PubMed

Hai, Heng-lin; Shen, Chuan-an; Chai, Jia-ke; Li, Hua-tao

2012-02-01

To explore the clinical effect of transplantation of the long head of biceps femoris muscle flap in combination with semi-V posterior thigh fasciocutaneous flap for repair of pressure sores over ischial tuberosity. Eight patients with 10 deep pressure sores over ischial tuberosity were admitted to the First Affiliated Hospital to the PLA General Hospital and the 98th Hospital of PLA from April 2004 to June 2010. The wounds measured from 2 cm × 2 cm to 6 cm × 4 cm were covered with the long head of biceps femoris muscle flap and semi-V posterior thigh fasciocutaneous flap (ranged from 10 cm × 6 cm to 13 cm × 8 cm). The condition of flaps was observed and followed up for a long time. All flaps survived. Nine wounds healed by first intention. Subcutaneous accumulation of fluids occurred in one wound with formation of a sinus at drainage site, and it healed after dressing change for 25 days. Patients were followed up for 7 to 34 months. Sore recurred in one patient 9 months after surgery, and it was successfully repaired with the same flap for the second time. Flaps in the other 7 patients appeared satisfactory with soft texture and without ulceration. This combined flap is easy in formation and transfer, and it causes little side injury with good resistance against pressure. It is a new method for repair of pressure sore over sacral region.

Active Management of Flap-Edge Trailing Vortices

NASA Technical Reports Server (NTRS)

Greenblatt, David; Yao, Chung-Sheng; Vey, Stefan; Paschereit, Oliver C.; Meyer, Robert

2008-01-01

The vortex hazard produced by large airliners and increasingly larger airliners entering service, combined with projected rapid increases in the demand for air transportation, is expected to act as a major impediment to increased air traffic capacity. Significant reduction in the vortex hazard is possible, however, by employing active vortex alleviation techniques that reduce the wake severity by dynamically modifying its vortex characteristics, providing that the techniques do not degrade performance or compromise safety and ride quality. With this as background, a series of experiments were performed, initially at NASA Langley Research Center and subsequently at the Berlin University of Technology in collaboration with the German Aerospace Center. The investigations demonstrated the basic mechanism for managing trailing vortices using retrofitted devices that are decoupled from conventional control surfaces. The basic premise for managing vortices advanced here is rooted in the erstwhile forgotten hypothesis of Albert Betz, as extended and verified ingeniously by Coleman duPont Donaldson and his collaborators. Using these devices, vortices may be perturbed at arbitrarily long wavelengths down to wavelengths less than a typical airliner wingspan and the oscillatory loads on the wings, and hence the vehicle, are small. Significant flexibility in the specific device has been demonstrated using local passive and active separation control as well as local circulation control via Gurney flaps. The method is now in a position to be tested in a wind tunnel with a longer test section on a scaled airliner configuration. Alternatively, the method can be tested directly in a towing tank, on a model aircraft, a light aircraft or a full-scale airliner. The authors believed that this method will have significant appeal from an industry perspective due to its retrofit potential with little to no impact on cruise (devices tucked away in the cove or retracted); low operating power

[Predictability of the corneal flap creation with the femtosecond laser in LASIK].

PubMed

Mai, Zhi-bin; Liu, Su-bing; Nie, Xiao-li; Sun, Hong-xia; Xin, Bao-li; Tang, Xiu-xia

2012-05-01

To observe the predictability of corneal flap creation with the FEMTO LDV femtosecond laser and analyze preliminarily the factors correlating to the thickness and diameter of the flap . It was a study of serial cases. 260 eyes of 130 consecutive patients were treated with the FEMTO LDV. The eyes were assigned to two groups according to intended flap thickness, 110 µm (208 eyes) and 90 µm (52 eyes). Intended flap diameter varied from 8.5 to 9.5 mm. Difference analysis of flap diameter and intended diameter as well as flap thickness and intended thickness were made. The data was analyzed with SPSS to sum up a multiple stepwise regression formula that could express their quantitative relationship. The 90 µm flap group had a average flap thickness of (95.12 ± 7.65) µm, while for the 110 µm group the average flap thickness was (104.81 ± 3.09) µm. The difference between right and left eyes was not statistically significant (t(110 µm) = -1.223, t(90 µm) = -1.343, P > 0.05). Corneal flap thickness was inversely correlated with flap diameter (r(110 µm) = -0.143, r(90 µm) = -0.315, P < 0.05), but was not related to preoperative patient age, corneal thickness, keratometric value K or intraocular pressure (r(110 µm) = -0.160, 0.054, -0.011, -0.363; r(90 µm) = 0.024, 0.074, -0.212, -0.434, all P > 0.05). Corneal flap diameter was positively correlated with preoperative corneal keratometric value K and thickness (P < 0.001, P < 0.05). Multiple stepwise regression analysis showed flap diameter was an influencing factor for flap thickness. Preoperative corneal keratometric value K and thickness were influencing factors for flap diameter. The LASIK flap creation with the FEMTO LDV laser has relatively good predictability. Flap diameter is an influencing factor for flap thickness.

A bio-inspired study on tidal energy extraction with flexible flapping wings.

PubMed

Liu, Wendi; Xiao, Qing; Cheng, Fai

2013-09-01

Previous research on the flexible structure of flapping wings has shown an improved propulsion performance in comparison to rigid wings. However, not much is known about this function in terms of power efficiency modification for flapping wing energy devices. In order to study the role of the flexible wing deformation in the hydrodynamics of flapping wing energy devices, we computationally model the two-dimensional flexible single and twin flapping wings in operation under the energy extraction conditions with a large Reynolds number of 106. The flexible motion for the present study is predetermined based on a priori structural result which is different from a passive flexibility solution. Four different models are investigated with additional potential local distortions near the leading and trailing edges. Our simulation results show that the flexible structure of a wing is beneficial to enhance power efficiency by increasing the peaks of lift force over a flapping cycle, and tuning the phase shift between force and velocity to a favourable trend. Moreover, the impact of wing flexibility on efficiency is more profound at a low nominal effective angle of attack (AoA). At a typical flapping frequency f * = 0.15 and nominal effective AoA of 10°, a flexible integrated wing generates 7.68% higher efficiency than a rigid wing. An even higher increase, around six times that of a rigid wing, is achievable if the nominal effective AoA is reduced to zero degrees at feathering condition. This is very attractive for a semi-actuated flapping energy system, where energy input is needed to activate the pitching motion. The results from our dual-wing study found that a parallel twin-wing device can produce more power compared to a single wing due to the strong flow interaction between the two wings.

Principles of definitive soft tissue coverage with flaps.

PubMed

Levin, L Scott

2008-01-01

Despite the emergence of negative pressure wound therapy with reticulated open cell foam (NPWT/ROCF) as delivered by V.A.C.(R) Therapy (KCI, San Antonio, TX) for orthopaedic trauma, vascularized tissue transfer whether it be pedicle, free, or tissue transfer using the operating microscope or as an island, remains the mainstay of soft tissue reconstruction for orthopaedic traumatology. The critisism of microvascular procedures has been that they are lengthy, costly, and required technical expertise to perform. While technical skills are required, microsurgical care has evolved into a routine operation with high degrees of success in experienced hand. The problem that still remains is access to surgeons who are interested in soft tissue reconstruction and can perform definitive coverage with flaps. There is a need in the orthopaedic community to solve the problem of lack of flap surgeons and as a result, NPWT/ROCF has been touted as the answer to flap reconstruction. NPWT/ROCF is an important addition to soft tissue reconstruction but it serves as a bridge rather than definitive coverage in many hands. Just as wound technology is evolving with tissue substitutes, growth factors and NPWT/ROCF flaps technology continues to advance with new perforator flaps and local regional flaps, particularly the sural flap, coming on line as mainstays of soft tissue reconstruction.

Droplet ejection and sliding on a flapping film

NASA Astrophysics Data System (ADS)

Chen, Xi; Doughramaji, Nicole; Betz, Amy Rachel; Derby, Melanie M.

2017-03-01

Water recovery and subsequent reuse are required for human consumption as well as industrial, and agriculture applications. Moist air streams, such as cooling tower plumes and fog, represent opportunities for water harvesting. In this work, we investigate a flapping mechanism to increase droplet shedding on thin, hydrophobic films for two vibrational cases (e.g., ± 9 mm and 11 Hz; ± 2 mm and 100 Hz). Two main mechanisms removed water droplets from the flapping film: vibrational-induced coalescence/sliding and droplet ejection from the surface. Vibrations mobilized droplets on the flapping film, increasing the probability of coalescence with neighboring droplets leading to faster droplet growth. Droplet departure sizes of 1-2 mm were observed for flapping films, compared to 3-4 mm on stationary films, which solely relied on gravity for droplet removal. Additionally, flapping films exhibited lower percentage area coverage by water after a few seconds. The second removal mechanism, droplet ejection was analyzed with respect to surface wave formation and inertia. Smaller droplets (e.g., 1-mm diameter) were ejected at a higher frequency which is associated with a higher acceleration. Kinetic energy of the water was the largest contributor to energy required to flap the film, and low energy inputs (i.e., 3.3 W/m2) were possible. Additionally, self-flapping films could enable novel water collection and condensation with minimal energy input.

"Reading man flap" design for reconstruction of circular infraorbital and malar skin defects.

PubMed

Seyhan, Tamer; Caglar, Baris

2008-11-01

Surgical complications such as lid retraction and ectropion from graft or flap scar contracture make reconstruction of skin defects in the malar and infraorbital regions challenging. A new flap design, the reading man flap, was used to overcome these problems. The Limberg and bilobed flap were compared with the reading man flap. The reading man flap consists mainly of a superiorly based quadrangular flap and an inferiorly based triangular flap. Malar and infraorbital circular skin defects measuring 14 x 14 to 40 x 40 mm were reconstructed with a reading man flap in 13 patients. The defects occurred after basal cell carcinoma in all patients. The Limberg flap, bilobed flap, and reading man flap were planned for same-sized defects on the abdominoplasty resection material. The results were compared in terms of total scar area, scar length, and total healthy skin area discarded. When comparing the 3 flap designs, the reading man flap was the most suitable flap in terms of total scar area and length. The reading man flap can be used to reconstruct malar and infraorbital circular defects with good cosmetic results and without creating any tractional forces to the eyelids.

Noise Radiation from a Continuous Mold-Line Link Flap Configuration

NASA Technical Reports Server (NTRS)

Hutcheson, Florence V.; Brooks, Thomas F.; Humphreys, William M., Jr.

2011-01-01

The results of an experimental study of the noise from a Continuous Mold-Line Link (CML) flap are presented. Acoustic and unsteady surface pressure measurements were performed on a main element wing section with a half-span CML flap in NASA Langley s Quiet Flow Facility. The acoustic data were acquired with a medium aperture directional array (MADA) of microphones. The Deconvolution Approach for the Mapping of Acoustic Sources (DAMAS) method is applied to determine the spatial distribution and strength of the noise sources over the surface of the test model. A Coherent Output Power (COP) method which relates the output from unsteady surface pressure sensors to the output of the MADA is also used to obtain more detailed characteristics of the noise source distribution in the trailing edge region of the CML. These results are compared to those obtained for a blunt flap to quantify the level of noise benefit that is achieved with the CML flap. The results indicate that the noise from the CML region of the flap is 5 to 17 dB lower (depending on flap deflection and Mach number) than the noise from the side edge region of the blunt flap. Lower noise levels are obtained for all frequencies. Spectral analysis of the noise from the cove region of the CML and blunt flap models also reveal a spectral peak in the high frequency range that is related to noise scattering at the trailing edge of the main element. The peaks in the CML and blunt flap cove noise spectra are close in level and often exceed blunt side edge noise. Applying a strip of serrated tape to the trailing edge of the CML flap model main airfoil reduced the peak but increased other noise somewhat. Directivity measurements show that the CML flap can be more directional than the blunt flap.

Noise Radiation from a Continuous Mold-Line Link Flap Configuration

NASA Technical Reports Server (NTRS)

Hutcheson, Florence V.; Brooks, Thomas F.; Humphreys, William M.

2008-01-01

The results of an experimental study of the noise from a Continuous Mold-Line Link (CML) flap are presented. Acoustic and unsteady surface pressure measurements were performed on a main element wing section with a half-span CML flap in NASA Langley s Quiet Flow Facility. The acoustic data were acquired with a medium aperture directional array (MADA) of microphones. The Deconvolution Approach for the Mapping of Acoustic Sources (DAMAS) method is applied to determine the spatial distribution and strength of the noise sources over the surface of the test model. A Coherent Output Power (COP) method which relates the output from unsteady surface pressure sensors to the output of the MADA is also used to obtain more detailed characteristics of the noise source distribution in the trailing edge region of the CML. These results are compared to those obtained for a blunt flap to quantify the level of noise benefit that is achieved with the CML flap. The results indicate that the noise from the CML region of the flap is 5 to 17 dB lower (depending on flap deflection and Mach number) than the noise from the side edge region of the blunt flap. Lower noise levels are obtained for all frequencies. Spectral analysis of the noise from the cove region of the CML and blunt flap models also reveal a spectral peak in the high frequency range that is related to noise scattering at the trailing edge of the main element. The peaks in the CML and blunt flap cove noise spectra are close in level and often exceed blunt side edge noise. Applying a strip of serrated tape to the trailing edge of the CML flap model main airfoil, reduced the peak but increased other noise somewhat. Directivity measurements show that the CML flap can be more directional than the blunt flap.

Traumatic corneal flap displacement after laser in situ keratomileusis (LASIK)

PubMed Central

Tsai, Tsung-Han; Peng, Kai-Ling; Lin, Chien-Jen

2017-01-01

Background Laser in situ keratomileusis (LASIK) is the most common and popular procedure performed for the correction of refractive errors in the last two decades. We report a case of traumatic flap displacement with flap folding which occurred 3 years after LASIK was performed. Previous literature suggests that vision prognosis would be closely related to proper and prompt management of traumatic flap displacement with flap folding 3 years after LASIK. Case presentation A 23-year-old female presented to our hospital who had undergone uneventful LASIK in both eyes 3 years prior. Unfortunately, she had suffered a blunt trauma in her right eye in a car accident. A late onset of corneal flap displacement was found with upper and lower portion of the flap being folded inside the corneal bed. Surgical intervention for debridement with subsequent reposition of corneal flap was performed as soon as possible in the operating room. A bandage contact lens was placed, and topical antibiotic and corticosteroids were given postoperatively. Two days after the operation, the displaced corneal flap was found to be well attached smoothly on the corneal bed without folds. The best-corrected visual acuity was 6/6 with refraction of −0.75 D to 1.0 D ×175° in her right eye 1 month later. Literature review We reviewed a total of 19 published cases of late-onset traumatic flap dislocations or displacements after LASIK with complete data from 2000 to 2014. Conclusion Traumatic displacement of corneal flaps after LASIK may occur after blunt injury with specific direction of force to the flap margin, especially tangential one. According to the previous literature, late-onset traumatic flap displacement may happen at any time after LASIK and be caused by various types of injuries. Fortunately, good visual function could mostly be restored with immediate and proper management. PMID:28458585

Traumatic corneal flap displacement after laser in situ keratomileusis (LASIK).

PubMed

Tsai, Tsung-Han; Peng, Kai-Ling; Lin, Chien-Jen

2017-01-01

Laser in situ keratomileusis (LASIK) is the most common and popular procedure performed for the correction of refractive errors in the last two decades. We report a case of traumatic flap displacement with flap folding which occurred 3 years after LASIK was performed. Previous literature suggests that vision prognosis would be closely related to proper and prompt management of traumatic flap displacement with flap folding 3 years after LASIK. A 23-year-old female presented to our hospital who had undergone uneventful LASIK in both eyes 3 years prior. Unfortunately, she had suffered a blunt trauma in her right eye in a car accident. A late onset of corneal flap displacement was found with upper and lower portion of the flap being folded inside the corneal bed. Surgical intervention for debridement with subsequent reposition of corneal flap was performed as soon as possible in the operating room. A bandage contact lens was placed, and topical antibiotic and corticosteroids were given postoperatively. Two days after the operation, the displaced corneal flap was found to be well attached smoothly on the corneal bed without folds. The best-corrected visual acuity was 6/6 with refraction of -0.75 D to 1.0 D ×175° in her right eye 1 month later. We reviewed a total of 19 published cases of late-onset traumatic flap dislocations or displacements after LASIK with complete data from 2000 to 2014. Traumatic displacement of corneal flaps after LASIK may occur after blunt injury with specific direction of force to the flap margin, especially tangential one. According to the previous literature, late-onset traumatic flap displacement may happen at any time after LASIK and be caused by various types of injuries. Fortunately, good visual function could mostly be restored with immediate and proper management.

Aerodynamic effects of flexibility in flapping wings.

PubMed

Zhao, Liang; Huang, Qingfeng; Deng, Xinyan; Sane, Sanjay P

2010-03-06

Recent work on the aerodynamics of flapping flight reveals fundamental differences in the mechanisms of aerodynamic force generation between fixed and flapping wings. When fixed wings translate at high angles of attack, they periodically generate and shed leading and trailing edge vortices as reflected in their fluctuating aerodynamic force traces and associated flow visualization. In contrast, wings flapping at high angles of attack generate stable leading edge vorticity, which persists throughout the duration of the stroke and enhances mean aerodynamic forces. Here, we show that aerodynamic forces can be controlled by altering the trailing edge flexibility of a flapping wing. We used a dynamically scaled mechanical model of flapping flight (Re approximately 2000) to measure the aerodynamic forces on flapping wings of variable flexural stiffness (EI). For low to medium angles of attack, as flexibility of the wing increases, its ability to generate aerodynamic forces decreases monotonically but its lift-to-drag ratios remain approximately constant. The instantaneous force traces reveal no major differences in the underlying modes of force generation for flexible and rigid wings, but the magnitude of force, the angle of net force vector and centre of pressure all vary systematically with wing flexibility. Even a rudimentary framework of wing veins is sufficient to restore the ability of flexible wings to generate forces at near-rigid values. Thus, the magnitude of force generation can be controlled by modulating the trailing edge flexibility and thereby controlling the magnitude of the leading edge vorticity. To characterize this, we have generated a detailed database of aerodynamic forces as a function of several variables including material properties, kinematics, aerodynamic forces and centre of pressure, which can also be used to help validate computational models of aeroelastic flapping wings. These experiments will also be useful for wing design for small

Aerodynamic effects of flexibility in flapping wings

PubMed Central

Zhao, Liang; Huang, Qingfeng; Deng, Xinyan; Sane, Sanjay P.

2010-01-01

Recent work on the aerodynamics of flapping flight reveals fundamental differences in the mechanisms of aerodynamic force generation between fixed and flapping wings. When fixed wings translate at high angles of attack, they periodically generate and shed leading and trailing edge vortices as reflected in their fluctuating aerodynamic force traces and associated flow visualization. In contrast, wings flapping at high angles of attack generate stable leading edge vorticity, which persists throughout the duration of the stroke and enhances mean aerodynamic forces. Here, we show that aerodynamic forces can be controlled by altering the trailing edge flexibility of a flapping wing. We used a dynamically scaled mechanical model of flapping flight (Re ≈ 2000) to measure the aerodynamic forces on flapping wings of variable flexural stiffness (EI). For low to medium angles of attack, as flexibility of the wing increases, its ability to generate aerodynamic forces decreases monotonically but its lift-to-drag ratios remain approximately constant. The instantaneous force traces reveal no major differences in the underlying modes of force generation for flexible and rigid wings, but the magnitude of force, the angle of net force vector and centre of pressure all vary systematically with wing flexibility. Even a rudimentary framework of wing veins is sufficient to restore the ability of flexible wings to generate forces at near-rigid values. Thus, the magnitude of force generation can be controlled by modulating the trailing edge flexibility and thereby controlling the magnitude of the leading edge vorticity. To characterize this, we have generated a detailed database of aerodynamic forces as a function of several variables including material properties, kinematics, aerodynamic forces and centre of pressure, which can also be used to help validate computational models of aeroelastic flapping wings. These experiments will also be useful for wing design for small robotic

The Economy in Autologous Tissue Transfer: Part 1. The Kiss Flap Technique.

PubMed

Zhang, Yi Xin; Hayakawa, Thomas J; Levin, L Scott; Hallock, Geoffrey G; Lazzeri, Davide

2016-03-01

All reconstructive microsurgeons realize the need to improve aesthetic and functional donor-site outcomes. A "kiss" flap design concept was developed to increase the surface area of skin flap coverage while minimizing donor-site morbidity. The main goal of the kiss flap technique is to harvest multiple skin paddles that are smaller than those raised with traditional techniques, to minimize donor-site morbidity. These smaller flap components are then sutured to each other, or said to kiss each other side-by-side, to create a large, wide flap. The skin paddles in the kiss technique can be linked to one another by a variety of native intrinsic vascular connections, by additional microanastomosis, or both. This technique can be widely applied to both free and pedicle flaps, and essentially allows for the reconstruction of a large defect while providing the easy primary closure of a smaller donor-site defect. According to their origin of blood supply, kiss flaps are classified into three styles and five types. All of the different types of kiss flaps are unique in both flap design and harvest technique. Most kiss flaps are based on common flaps already familiar to the reconstructive surgeon. The basis of the kiss flap design concept is to convert multiple narrow flaps into a single unified flap of the desired greater width. This maximizes the size of the resulting flap and minimizes donor-site morbidity, as a direct linear closure is usually possible. Therapeutic, V.

Free 'mini' groin flap for digital resurfacing.

PubMed

Tare, M; Ramakrishnan, V

2009-06-01

Ten cases of post-traumatic skin and soft tissue loss over the digits were resurfaced by free 'mini' groin flap. Five patients had defects of the dorsum of the digit, three had proximal palmar defects, one patient had circumferential skin loss and one had multiple digital injuries. The flap was harvested from the contralateral groin using a two-team approach. The average size of the flap was 5.5 x 4.75 cm and the mean operating time was 2.45 hrs. All patients had physiotherapy within 48-72 hrs. There were no flap losses. Six patients were happy with the cosmetic result and did not require any further debulking. We recommend free tissue transfer for digital resurfacing specifically in moderate to large dorsal defects, proximal volar defects, circumferential skin loss and multiple digit injuries.

The Gradual Expansion Muscle Flap

DTIC Science & Technology

2014-01-01

acute shortening and angulation of the tibia and rotational muscle flap coverage and split thickness skin grafting of the soft tissue defect...is also amenable to split-thickness skin grafting after tissue incorporation.11 In addition to donor site morbidity, free tissue transfer is dependent...necessary soft tissue coverage. In the second stage, after the flap has adequately set and overlying skin graft has full adherence, a Taylor Spatial

A novel animal model for skin flap prelamination with biomaterials

NASA Astrophysics Data System (ADS)

Zhou, Xianyu; Luo, Xusong; Liu, Fei; Gu, Chuan; Wang, Xi; Yang, Qun; Qian, Yunliang; Yang, Jun

2016-09-01

Several animal models of skin flap construction were reported using biomaterials in a way similar to prefabrication. However, there are few animal model using biomaterials similar to prelamination, another main way of clinical skin flap construction that has been proved to be reliable. Can biomaterials be added in skin flap prelamination to reduce the use of autogenous tissues? Beside individual clinical attempts, animal model is needed for randomized controlled trial to objectively evaluate the feasibility and further investigation. Combining human Acellular Dermal Matrix (hADM) and autologous skin graft, we prelaminated flaps based on inguinal fascia. One, two, three and four weeks later, hADM exhibited a sound revascularization and host cell infiltration. Prelaminated skin flaps were then raised and microsurgically transplanted back to groin region. Except for flaps after one week of prelamination, flaps from other subgroups successfully reconstructed defects. After six to sixteen weeks of transplantation, hADM was proved to being able to maintain its original structure, having a wealth of host tissue cells and achieving full revascularization.To our knowledge, this is the first animal model of prelaminating skin flap with biomaterials. Success of this animal model indicates that novel flap prelamination with biomaterials is feasible.

Blood Perfusion in Human Eyelid Skin Flaps Examined by Laser Speckle Contrast Imaging-Importance of Flap Length and the Use of Diathermy.

PubMed

Nguyen, Cu Dinh; Hult, Jenny; Sheikh, Rafi; Tenland, Kajsa; Dahlstrand, Ulf; Lindstedt, Sandra; Malmsjö, Malin

2017-10-11

It is well known that blood perfusion is important for the survival of skin flaps. As no study has been conducted to investigate how the blood perfusion in human eyelid skin flaps is affected by the flap length and diathermy, the present study was carried out to investigate these in patients. Fifteen upper eyelids were dissected as part of a blepharoplastic procedure, releasing a 30-mm long piece of skin, while allowing the 5 mm wide distal part of the skin to remain attached, to mimic a skin flap (hereafter called a "skin flap"). Blood perfusion was measured before and after repeated diathermy, using laser speckle contrast imaging. Blood perfusion decreased from the base to the tip of the flap: 5 mm from the base, the perfusion was 69%, at 10 mm it was 40%, at 15 mm it was 20%, and at 20 mm it was only 13% of baseline values. Diathermy further decreased blood perfusion (measured 15 mm from the base) to 13% after applying diathermy for the first time, to 6% after the second and to 4% after the third applications of diathermy. Blood perfusion falls rapidly with distance from the base of skin flaps on the human eyelid, and diathermy reduces blood perfusion even further. Clinically, it may be advised that flaps with a width of 5 mm be no longer than 15 mm (i.e., a width:length ratio of 1:3), and that the use of diathermy should be carefully considered.

Surgical Repair of Mid-shaft Hypospadias Using a Transverse Preputial Island Flap and Pedicled Dartos Flap Around Urethral Orifice.

PubMed

Liang, Weiqiang; Ji, Chenyang; Chen, Yuhong; Zhang, Ganling; Zhang, Jiaqi; Yao, Yuanyuan; Zhang, Jinming

2016-08-01

To evaluate the effects, particularly the incidence of anastomotic fistula, of a pedicled dartos flap around the urethral orifice in the treatment of urethroplasty of mid-shaft hypospadias. A total of 46 cases of congenital mid-shaft hypospadias were included in this study. The patients ranged in age from 0.7 to 25.4 years and the average was 5.8 years. The patients received penis chordee correction. A transverse preputial island flap was developed for urethral reconstruction. The proximal dartos of the urethral orifice was used to develop a pedicled dartos flap, which was transposed to cover and strengthen neourethral anastomosis. The ventral penile skin defect was repaired by another flap. The 46 patients were examined during follow-up visits for 6 months to 3 years. An anastomotic fistula was observed in one case (2.2 %). Scar healing without fistula was observed in another patient due to poor blood supply to part of the ventral penile skin. No other incidences of fistula, urethral rupture, flap necrosis, wound infections, urinary tract (meatal) stenosis, or urethral diverticulum were observed in the patients. A pedicled dartos flap around the urethral orifice can take advantage of well-vascularized local tissue to add a protective layer to the proximal aspect of the neourethral anastomosis for reducing the incidence of anastomotic fistula in mid-shaft hypospadias repair using a transverse preputial island flap. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

"Apron" flap and re-creation of the inframammary fold following TRAM flap breast reconstruction.

PubMed

Amir, A; Silfen, R; Hauben, D J

2000-03-01

To the best of our knowledge, the recreation of an inframammary fold after TRAM flap breast reconstruction has not yet been described. This article offers a technique for the creation of an inframammary fold as a secondary procedure. The technique has been performed thus far in two patients with good aesthetic outcomes and no postoperative complications. It may also be suitable for adding bulk to the TRAM flap, especially in bilateral breast reconstruction, and for other minor chest deformities.

Long-Term Patency of Twisted Vascular Pedicles in Perforator-Based Propeller Flaps.

PubMed

Jakubietz, Rafael G; Nickel, Aljoscha; Neshkova, Iva; Schmidt, Karsten; Gilbert, Fabian; Meffert, Rainer H; Jakubietz, Michael G

2017-10-01

Propeller flaps require torsion of the vascular pedicle of up to 180 degrees. Contrary to free flaps, where the relevance of an intact vascular pedicle has been documented, little is known regarding twisted pedicles of propeller flaps. As secondary surgeries requiring undermining of the flap are common in the extremities, knowledge regarding the necessity to protect the pedicle is relevant. The aim of this study was a long-term evaluation of the patency of vascular pedicle of propeller flaps. In a retrospective clinical study, 22 patients who underwent soft-tissue reconstruction with a propeller flap were evaluated after 43 months. A Doppler probe was used to locate and evaluate the patency of the vascular pedicle of the flap. The flaps were used in the lower extremity in 19 cases, on the trunk in 3 cases. All flaps had healed. In all patients, an intact vascular pedicle could be found. Flap size, source vessel, or infection could therefore not be linked to an increased risk of pedicle loss. The vascular pedicle of propeller flaps remains patent in the long term. This allows reelevation and undermining of the flap. We therefore recommend protecting the pedicle in all secondary cases to prevent later flap loss.

A standardized model for predicting flap failure using indocyanine green dye

NASA Astrophysics Data System (ADS)

Zimmermann, Terence M.; Moore, Lindsay S.; Warram, Jason M.; Greene, Benjamin J.; Nakhmani, Arie; Korb, Melissa L.; Rosenthal, Eben L.

2016-03-01

Techniques that provide a non-invasive method for evaluation of intraoperative skin flap perfusion are currently available but underutilized. We hypothesize that intraoperative vascular imaging can be used to reliably assess skin flap perfusion and elucidate areas of future necrosis by means of a standardized critical perfusion threshold. Five animal groups (negative controls, n=4; positive controls, n=5; chemotherapy group, n=5; radiation group, n=5; chemoradiation group, n=5) underwent pre-flap treatments two weeks prior to undergoing random pattern dorsal fasciocutaneous flaps with a length to width ratio of 2:1 (3 x 1.5 cm). Flap perfusion was assessed via laser-assisted indocyanine green dye angiography and compared to standard clinical assessment for predictive accuracy of flap necrosis. For estimating flap-failure, clinical prediction achieved a sensitivity of 79.3% and a specificity of 90.5%. When average flap perfusion was more than three standard deviations below the average flap perfusion for the negative control group at the time of the flap procedure (144.3+/-17.05 absolute perfusion units), laser-assisted indocyanine green dye angiography achieved a sensitivity of 81.1% and a specificity of 97.3%. When absolute perfusion units were seven standard deviations below the average flap perfusion for the negative control group, specificity of necrosis prediction was 100%. Quantitative absolute perfusion units can improve specificity for intraoperative prediction of viable tissue. Using this strategy, a positive predictive threshold of flap failure can be standardized for clinical use.

The changing role of pectoralis major flap in head and neck reconstruction.

PubMed

Liu, Hin-Lun; Chan, Jimmy Yu-Wai; Wei, William Ignace

2010-11-01

Although pectoralis major flap (PM flap) has been used as the workhorse flap in head and neck reconstruction, its use in head and neck defects seems to fall out of favour in the era of free tissue transfer. The aim of this review is to find out the role of PM flap in modern head and neck surgery. Medical records of patients who underwent PM flap reconstruction for head and neck defect in our division were reviewed. The age, gender, flap type, indication and complication rate were described. Between January 1998 and December 2008, 202 PM flaps were used for head and neck reconstruction in 192 patients. In the early study period (1998-June 2003), out of the 119 PM flap reconstructions, 106 (89%) were performed for immediate reconstruction after resection of head and neck tumour, while 10 (8%) were performed as salvage procedures for complication after tumour resection e.g. failure of free flap, pharyngocutaneous fistula. In the late study period (July 2003-2008), out of the 83 PM flap reconstructions, 58 (70%) were performed for immediate reconstruction, while 24 (29%) were performed as salvage procedures. For immediate reconstruction after tumour extirpation, 51 flaps (48%) were performed for reconstruction of the tongue in the early study period, while only 14 (24%) were performed in the late study period. The number of PM flap used for immediate reconstruction for other head and neck defects remained relatively static throughout the two study periods. Over the study period, there were 10 (5%) cases of partial flap necrosis and 2 (1%) total flap loss, making the overall flap necrosis rate 6%. In the era of free tissue transfer, the role of PM flap in head and neck surgery has shifted from immediate reconstruction to salvage operation. However, PM flap still has an unique role in the repair of certain head and neck defects.

Submental island flap reconstruction reduces cost in oral cancer reconstruction compared to radial forearm free flap reconstruction: a case series and cost analysis.

PubMed

Forner, D; Phillips, T; Rigby, M; Hart, R; Taylor, M; Trites, J

2016-02-05

In Canada, 4,400 cases of oral cancer are diagnosed yearly. Surgical resection is a key component of treatment in many of these cancers. Reconstruction of defects, with the goal of preserving function, is of utmost importance. Several choices are possible for reconstruction of larger defects, including both free and pedicled flaps. Free flap reconstruction is reliable and effective, but requires additional personnel and peri-operative resources. Pedicled flaps remain an important alternative to free flaps, and are less resource intensive. This paper reviews our inaugural experience with the submental island flap (SIF) and compares costs incurred to a matched cohort of oral cancer patients reconstructed with forearm free flaps. Charts of patients who underwent SIF and RFFF reconstruction from January 1st 2013 to April 1st 2015 were retrospectively examined. Associated costs were obtained via online database and previously reported costs at the study institution. Mean length of ICU stay in glossectomy RFFF reconstruction was 4.7 days. Only one patient required ICU stay for one night in the SIF group. Mean length of hospital stay was not significantly different in SIF patients vs RFFF patients (12.4 vs 15.4 days, p > 0.05). Mean operative time was significantly lower in the SIF group compared to the RFFF group (347 vs 552 min, p < 0.05). Total mean intraoperative costs were found to be $4780.59 for RFFF operations, versus $2307.94 for SIF. Total mean cost of post-operative stay was $18158.40 in the SIF group and $43617.60 in the RFFF group. Total cost savings were therefore $27931.85 per patient for the SIF group. We have demonstrated the use of the submental island flap as an alternative to radial forearm free flaps, showing both decreased hospital costs and comparable patient outcomes. Pedicled flaps are making a resurgence in head and neck reconstruction, and the submental island flap offers an excellent alternative to more labour intensive and costly free

Multiple-digit resurfacing using a thin latissimus dorsi perforator flap.

PubMed

Kim, Sang Wha; Lee, Ho Jun; Kim, Jeong Tae; Kim, Youn Hwan

2014-01-01

Traumatic digit defects of high complexity and with inadequate local tissue represent challenging surgical problems. Recently, perforator flaps have been proposed for reconstructing large defects of the hand because of their thinness and pliability and minimal donor site morbidity. Here, we illustrate the use of thin latissimus dorsi perforator flaps for resurfacing multiple defects of distal digits. We describe the cases of seven patients with large defects, including digits, circumferential defects and multiple-digit defects, who underwent reconstruction with thin latissimus dorsi perforator flaps between January 2008 and March 2012. Single-digit resurfacing procedures were excluded. The mean age was 56.3 years and the mean flap size was 160.4 cm(2). All the flaps survived completely. Two patients had minor complications including partial flap loss and scar contracture. The mean follow-up period was 11.7 months. The ideal flap for digit resurfacing should be thin and amenable to moulding, have a long pedicle for microanastomosis and have minimal donor site morbidity. Thin flaps can be harvested by excluding the deep adipose layer, and their high pliability enables resurfacing without multiple debulking procedures. The latissimus dorsi perforator flap may be the best flap for reconstructing complex defects of the digits, such as large, multiple-digit or circumferential defects, which require complete wrapping of volar and dorsal surfaces. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

The inferior turbinate flap in skull base reconstruction

PubMed Central

2013-01-01

Background As the indications for expanded endonasal approaches continue to evolve, alternative reconstructive techniques are needed to address increasingly complex surgical skull base defects. In the absence of the nasoseptal flap, we describe our experience with the posterior pedicle inferior turbinate flap (PPITF) in skull base reconstruction. Design Case series. Setting Academic tertiary care centre. Methods Patients who underwent reconstruction of the skull base with the PPITF were identified. Medical records were reviewed for demographic, presentation, treatment, follow-up, surgical and outcomes data. Main outcome measures Flap survival, adequacy of seal, and complications. Results Two patients with residual/recurrent pituitary adenomas met the inclusion criteria. The nasoseptal flap was unavailable in each case due to a prior septectomy. Salvage of the original nasoseptal flap was not possible, as it did not provide adequate coverage of the resultant defect due to contraction from healing. All PPITFs healed uneventfully and covered the entire defect. No complications were observed in the early post-operative period. Endoscopic techniques and limitations of the PPITF are also discussed. Conclusions Our clinical experience supports the PPITF to be a viable alternative for reconstruction of the skull base in the absence of the nasoseptal flap. PMID:23663897

Clinical application of scrotal flap on penis lengthening.

PubMed

Zhuo, Qinqiang; Li, Shirong; Wu, Julong; Wang, Zhenxiang; Yang, Dongyun; Tao, Ling

2009-03-01

To investigate the clinical application of the scrotal flap on penis lengthening. One hundred and fifty-two patients were operated using the scrotal flap from July 1998 to January 2008 at the Department of Plastic and Aesthetic, Surgery Southwest Hospital, Chongqing, China. The procedure consisted of designing a positive sign shaped incision 1.5cm above the root of the penis, dissect and release the superficial suspensory ligament and part of the deep suspensory ligament, then cover the elongated cavernosum with proper scrotal flap. Six-month to 5-year follow-up showed that all patients were satisfied with the good contour and function of the penis. The operation was successful. The method of using scrotal flap on penis lengthening has the following advantages: simple operation, reliable blood supply of the flap, one-stage operation, and satisfactory postoperative results. It is a preferable operation technique for penis lengthening.

Postoperative morphine requirements of free TRAM and DIEP flaps.

PubMed

Kroll, S S; Sharma, S; Koutz, C; Langstein, H N; Evans GRD; Robb, G L; Chang, D W; Reece, G P

2001-02-01

In a review of the charts of 158 patients who had undergone breast reconstruction with free transverse rectus abdominis musculocutaneous (TRAM) or deep inferior epigastric perforator (DIEP) flaps and who were treated for postoperative pain with morphine administered by a patient-controlled analgesia pump, the total dose of morphine administered during hospitalization for the flap transfer was measured. Patients whose treatment was supplemented by other intravenous narcotics were excluded from the study. The mean amount of morphine per kilogram required by patients who had reconstruction with DIEP flaps (0.74 mg/kg, n = 26) was found to be significantly less than the amount required by patients who had reconstruction with TRAM flaps (1.65 mg/kg; n = 132; p < 0.001). DIEP flap patients also remained in the hospital less time (mean, 4.73 days) than did free TRAM flap patients (mean, 5.21 days; p = 0.026), but the difference was less than one full hospital day. It was concluded that the use of the DIEP flap does reduce the patient requirement for postoperative pain medication and therefore presumably reduces postoperative pain. It may also slightly shorten hospital stay.

Wind tunnel tests of the GA(W)-2 airfoil with 20% aileron, 25% slotted flap, 30% Fowler flap and 10% slot-lip spoiler

NASA Technical Reports Server (NTRS)

Wentz, W. H., Jr.

1977-01-01

Two dimensional wind tunnel tests were conducted for the GA(W)-2 airfoil section with: 20% aileron, 25% slotted flap; 30% Fowler flap, and 10% slot-lip spoiler. All tests were conducted at a Reynolds number of 2,200,000 and a Mach Number of 0.13. In addition to force measurements, tuft studies were conducted for the slotted and Fowler flap configurations. Aileron and spoiler hinge moments were obtained by integration of surface pressure measurements. Tests results show that a value of 3.82 was obtained with 30% Fowler flap. Aileron control effectiveness and hinge moments were similar to other airfoils. The slot-lip spoiler provided powerful, positive roll control at all flap settings.

Free style perforator based propeller flaps: Simple solutions for upper extremity reconstruction!

PubMed

Panse, Nikhil; Sahasrabudhe, Parag

2014-01-01

The introduction of perforator flaps by Koshima et al. was met with much animosity in the plastic surgery fraternity. The safety concerns of these flaps following the intentional twist of the perforators have prevented widespread adoption of this technique. Use of perforator based propeller flaps in the lower extremity is gradually on the rise, but their use in upper extremity reconstruction is infrequently reported, especially in the Indian subcontinent. We present a retrospective series of 63 free style perforator flaps used for soft tissue reconstruction of the upper extremity from November 2008 to June 2013. Flaps were performed by a single surgeon for various locations and indications over the upper extremity. Patient demographics, surgical indication, defect features, complications and clinical outcome are evaluated and presented as an uncontrolled case series. 63 free style perforator based propeller flaps were used for soft tissue reconstruction of 62 patients for the upper extremity from November 2008 to June 2013. Of the 63 flaps, 31 flaps were performed for trauma, 30 for post burn sequel, and two for post snake bite defects. We encountered flap necrosis in 8 flaps, of which there was complete necrosis in 4 flaps, and partial necrosis in four flaps. Of these 8 flaps, 7 needed a secondary procedure, and one healed secondarily. Although we had a failure rate of 12-13%, most of our failures were in the early part of the series indicative of a learning curve associated with the flap. Free style perforator based propeller flaps are a reliable option for coverage of small to moderate sized defects. Therapeutic IV.

Force Generation by Flapping Foils

NASA Astrophysics Data System (ADS)

Bandyopadhyay, P. R.; Donnelly, M.

1996-11-01

Aquatic animals like fish use flapping caudal fins to produce axial and cross-stream forces. During WW2, German scientists had built and tested an underwater vehicle powered by similar flapping foils. We have examined the forces produced by a pair of flapping foils. We have examined the forced produced by a pair of flapping foils attached to the tail end of a small axisymmetric cylinder. The foils operate in-phase (called waving), or in anti-phase (called clapping). In a low-speed water tunnel, we have undertaken time-dependent measurements of axial and cross-stream forces and moments that are exerted by the vortex shedding process over the entire body. Phase-matched LDV measurements of vorticity-velocity vectors, as well as limited flow visualization of the periodic vortex shedding process have also been carried out. The direction of the induced velocity within a pair of shed vortices determines the nature of the forces produced, viz., thrust or drag or cross-stream forces. The clapping mode produces a widely dispersed symmetric array of vortices which results in axial forces only (thrust and rag). On the other hand, the vortex array is staggered in the waving mode and cross-stream (maneuvering) forces are then generated.

Comparison of hatchet-shaped tensor fascia lata flap and pedicle anterior lateral thigh flap for treatment of trochanteric sores: a retrospective analysis of 48 patients.

PubMed

Li, Chun-Chang; Chang, Shun-Cheng; Fu, Ju-Peng; Tzeng, Yuan-Sheng; Wang, Chih-Hsing; Chen, Tim-Mo; Chen, Shyi-Gen

2013-12-01

Surgical reconstruction of trochanteric sores remains a formidable task for plastic surgeons. Diverse types of flaps have been proposed for use in this situation, each with particular advantages and limitations. This study aimed to compare the surgical outcomes between the hatchet-shaped tensor fascia lata (TFL) flap and the pedicle anterior lateral thigh (ALT) flap in treatment of trochanteric sores. Forty-eight patients with trochanteric sores were operated on under spinal or general anesthesia using TFL or ALT flaps between August 2007 and November 2010. In the TFL group, 26 hatchet-shaped TFL musculocutaneous flaps were performed on 24 patients. In the ALT group, 25 pedicle ALT musculocutaneous flaps were performed on 24 patients. Surgical outcomes were retrospectively analyzed. No significant difference was detected between the TFL and ALT groups in terms of age, preoperative disease period, obesity (body mass index), American Society of Anesthesiologists score, comorbidity, the defect size, follow-up time, and complication rate. The recurrence rate and the flap size were significantly higher in the TFL group than in the ALT group (P = 0.022; P < 0.001). The operation time was longer in the ALT group (P < 0.001). The pedicle ALT flap is a more effective treatment than the TFL flap for the surgical management of trochanteric sores. The hatchet-shaped TFL flap should be reserved for the reconstruction of recurrent trochanteric sores or for use in the critically ill patient who cannot tolerate longer anesthesia and operation time.

Paramuscular perforators in DIEAP flap for breast reconstruction.

PubMed

Pons, Gemma; Masia, Jaume; Sanchez-Porro, Lídia; Larrañaga, Jose; Clavero, Juan Angel

2014-12-01

One of the main steps in perforator flap surgery is to identify the dominant perforator. Using multidetector row computed tomography (MDCT) for the preoperative planning of deep inferior epigastric artery perforator (DIEAP) flap surgery, we identified a perforator with a large caliber, an excellent location in the middle abdominal region, and a totally extramuscular trajectory in a significant number of patients. We describe the frequency of this perforator and determine its characteristics. We conducted a retrospective study of 482 patients who underwent 526 DIEAP flaps for breast reconstruction from October 2003 to October 2011. Mean age at surgery was 51.3 years old. A preoperative MDCT of abdominal vascularization was performed in all patients. MDCT identified a dominant perforator with a paramuscular course in 12.4% of abdominal walls. In all cases, it was located in the midline and emerged directly from the deep inferior epigastric system. Its mean caliber was 1.9 mm. The flap was harvested based on this perforator in all these patients, and mean harvest time was 51 minutes. The characteristics of this perforator made dissection easier and reduced morbidity at the donor site. There were no flap losses and the only complications were minor. We located a paramuscular perforator in 12.4% of patients undergoing breast reconstruction with abdominal perforator flaps. Its morphological features and extramuscular course make it the perforator of choice in DIEAP flap surgery.

Distally based sural neuro-fasciocutaneous perforator flap for foot and ankle reconstruction: Surgical modifications for flap pedicle and donor site closure without skin graft.

PubMed

Chi, Zhenglin; Chen, Yiheng; Chu, Tinggang; Gao, Weiyang; Li, Zhijie; Yan, Hede; Song, Yonghuan

2018-02-01

The conventional procedure of the sural neuro-fasciocutaneous flap enables the supply of blood and venous drainage by increasing the width of the adipofascial tissue and preserving tiny venous return routes. Moreover, skin graft is a common method for donor site closure, which may lead to some complications and influence the aesthetic appearance. We report modifications for a distally based sural neuro-fasciocutaneous perforator flap and a relaying flap for donor site closure without skin graft. Twelve patients undergoing the modified flap for foot and ankle reconstruction were included in this study between 2014 and 2016. A peroneal-based perforator, a superficial vein, and the vascular axis of the sural nerve were included in the pedicle. A Z-shape skin incision was performed to explore the perforator vessels and a relaying island perforator flap was used to close the donor site. All flaps survived completely without necrosis. The area of the flaps ranged from 16 × 8 cm to 30 × 15 cm. The diameter width of the pedicle ranged from 1.0 to 2.0 cm. A relaying perforator island flap was used in 10 cases for donor site closure and no skin graft was performed. There were no serious donor site complications. All patients were satisfied with the aesthetic outcome postoperatively at the final follow-up. The distally based sural neuro-fasciocutaneous perforator flap is considered a reliable method for foot and ankle reconstruction. The modification for flap pedicle and donor site closure method without skin graft should be recommended. Copyright © 2017. Published by Elsevier Ltd.

Submental island pedicled flap vs radial forearm free flap for oral reconstruction: comparison of outcomes.

PubMed

Paydarfar, Joseph A; Patel, Urjeet A

2011-01-01

To compare intraoperative, postoperative, and functional results of submental island pedicled flap (SIPF) against radial forearm free flap (RFFF) reconstruction for tongue and floor-of-mouth reconstruction. Multi-institutional retrospective review. Academic tertiary referral center. Consecutive patients from February 2003 to December 2009 undergoing resection of oral tongue or floor of mouth followed by reconstruction with SIPF or RFFF. Two groups: SIPF vs RFFF. Duration of operation, hospital stay, surgical complications, and speech and swallowing function. The study included 60 patients, 27 with SIPF reconstruction and 33 with RFFF reconstruction. Sex, age, and TNM stage were similar for both groups. Mean flap size was smaller for SIPF (36 cm²) than for RFFF (50 cm²) (P < .001). Patients undergoing SIPF reconstruction had shorter operations (mean, 8 hours 44 minutes vs 13 hours 00 minutes; P < .001) and shorter hospitalization (mean, 10.6 days vs 14.0 days; P < .008) compared with patients who underwent RFFF. Donor site, flap-related, and other surgical complications were comparable between groups, as was speech and swallowing function. Reconstruction of oral cavity defects with the SIPF results in shorter operative time and hospitalization without compromising functional outcomes. The SIPF may be a preferable option in reconstruction of oral cavity defects less than 40 cm².

Desferrioxamine: a practical method for improving neovascularization of prefabricated flaps.

PubMed

Li, Bin; Li, Hua; Jin, Rui; Cheng, Chen; Wang, Jing; Zhu, Hainan; Zan, Tao; Li, Qingfeng; Hao, Lijun

2015-02-01

Prefabricated flaps are an ideal alternative to repair massive and complex tissue defects. Nevertheless, the risk of necrosis due to unpredictable blood supplies is a major obstacle to the application of prefabricated flaps. The survival of a prefabricated flap depends on the neovascularization between the vascular carrier and the donor tissue. Here, we proposed that the iron chelator, desferrioxamine (DFX), owned therapeutic effects that promoted the neovascularization of prefabricated flaps. An abdominal prefabricated flap model was created in rats via a 2-stage operation. The rats were allocated into 4 groups as follows: 2 groups of rats received DFX treatments during the first or the second stage of the operation, respectively; 1 group of rats received a delay procedure 1 week before the second operation; and the final group was used as a blank control. Flap survival rates and capillary densities were evaluated between groups. The influence of DFX on the dermal fibroblasts was also studied in vitro. Desferrioxamine treatment during the first stage of the operation greatly increased flap survival rate compared to the blank control. The results were similar to those produced by the delay treatment. The vessel count results were consistent with the flap survival rate findings. In vitro, DFX treatment up-regulated the expression levels of several angiogenic factors in the dermal fibroblasts. Nevertheless, DFX treatment during the second stage of the operation was therapeutically detrimental. The application of DFX around the time of vascular carrier implantation greatly promoted neovascularization of prefabricated flaps, but was therapeutically detrimental after the flaps had been elevated.

Flap preconditioning by pressure-controlled cupping in a rat model.

PubMed

Koh, Kyung S; Park, Sung Woo; Oh, Tae Suk; Choi, Jong Woo

2016-08-01

Flap survival is essential for the success of soft-tissue reconstruction. Accordingly, various surgical and medical methods aim to increase flap survival. Because flap survival is affected by the innate vascular supply, traditional preconditioning methods mainly target vasodilatation or vascular reorientation to increase blood flow to the tissue. External stress on the skin, such as an external volume expander or cupping, induces vascular remodeling, and these approaches have been used in the fat grafting field and in traditional Asian medicine. In the present study, we used a rat random-pattern dorsal flap model to study the effectiveness of preconditioning with an externally applied device (cupping) at the flap site that directly applied negative pressure to the skin. The device, the pressure-controlled cupping, is connected to negative pressure vacuum device providing accurate pressure control from 0 mm Hg to -200 mm Hg. Flap surgery was performed after preconditioning under -25 mm Hg suction pressure for 30 min a day for 5 d, followed by 9 d of postoperative observation. Flap survival was assessed as the area of viable tissue and was compared between the preconditioned group and a control group. The preconditioned group showed absolute percentage increase of flap viability relative to the entire flap by 19.0± 7.6% (average 70.1% versus 51.0%). Tissue perfusion of entire flap, evaluated by laser Doppler imaging system, was improved with absolute percentage increase by 24.2± 10.4% (average 77.4% versus 53.1%). Histologic analysis of hematoxylin and eosin, CD31, and Masson-trichrome staining showed increased vascular density in the subdermal plexus and more organized collagen production with hypertrophy of the attached muscle. Our study suggests that flap preconditioning caused by controlled noninvasive suction induces vascular remodeling that increases tissue perfusion and improves flap survival in a rat model. Copyright © 2016 Elsevier Inc. All rights

Efficacy of Liposuction as a Delay Method for Improving Flap Survival.

PubMed

Orhan, Erkan; Erol, Yağmur Reyyan; Deren, Orgun; Altun, Serdar; Erdoğan, Bülent

2016-12-01

Flaps are often used in repairing tissue defects and partial or full flap loss is still an important morbidity cause. Several techniques have been tried to increase flap circulation but none of these could replace the delay technique. Our goal in this study is to show the efficacy of liposuction in delay of dorsal rat cutaneous flaps and improvement in flap survival. Twenty-four Wistar rats were used. The rats in group 1 received 9 × 3-sized caudally-based random pattern skin flaps. In group 2, liposuction was done under the tissue island spotted as the flap and after 14 days, standard flap surgery was done. In group 3, surgical delay was done and after 14 days, standard flap surgery was done. In group 4, liposuction was done under the tissue island spotted as the flap and standard flap surgery was done right after the liposuction. The rate of necrotic tissue in group 3 (surgical delay; mean % 13.7) was less than the rate in group 2 (liposuction delay; mean % 15.1), although the difference was not statistically significant. The necrosis rates in group 3 (surgical delay) and group 2 (liposuction delay) were less than the rates in both group 1 (only flap; mean % 41.5) and group 4 (liposuction flap; mean % 40.0) and this difference was statistically significant (p < 0.0001). Liposuction can be an alternative to surgical delay as a less invasive method in the clinic. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Sexual dysfunction after colpectomy and vaginal reconstruction with a vertical rectus abdominis myocutaneous flap.

PubMed

Løve, Uffe S; Sjøgren, Pia; Rasmussen, Peter; Laurberg, Søren; Christensen, Henrik K

2013-02-01

The use of the vertical rectus abdominis myocutaneous flap in reconstruction after abdominoperineal resection or pelvic exenteration for neoplasia is well documented. However, functional outcomes after vaginal reconstruction, including sexual function, are poorly described. This study aimed to examine sexual function in women following extensive pelvic surgery with colpectomy and vaginal reconstruction with the use of a vertical rectus abdominis myocutaneous flap. This study is a retrospective review of medical records in combination with patient questionnaires. Nonresponders were followed up with a second contact. This study was performed at a tertiary care university medical center (Colorectal Section, Department of Surgery P, Aarhus University Hospital, Denmark) All women undergoing pelvic surgery and simultaneous vaginal reconstruction with the use of a vertical rectus abdominis myocutaneous flap between 2004 and 2010 at our department were identified from a patient database. Thirty women who were alive at the time of identification were included in the study. Sexual function before and after surgery was evaluated by the use of the Sexual function Vaginal changes Questionnaire. The main outcome end point was whether the patient was sexually active after vaginal reconstruction. Twenty-six participants (87%) answered the questionnaire. Fifty percent of patients reported an active sex life before surgery. In general, patients reported an unchanged desire for both physical and sexual contact after surgery. However, only 2 patients (14%) reported being sexually active after surgery. This was a retrospective study with a heterogeneous cohort involving several types of cancers and surgical procedures. Factors other than vertical rectus abdominis myocutaneous flap reconstruction itself may interfere with the sexual function. Extensive pelvic surgery with colpectomy leads to sexual dysfunction even when the vagina is reconstructed with a vertical rectus abdominis

Medium- and Large-Sized Autologous Breast Reconstruction using a Fleur-de-lys Profunda Femoris Artery Perforator Flap Design: A Report Comparing Results with the Horizontal Profunda Femoris Artery Perforator Flap.

PubMed

Hunsinger, Vincent; Lhuaire, Martin; Haddad, Kevin; Wirz, Francesco-Saverio; Abedalthaqafi, Samah; Obadia, Déborah; Derder, Mohamed; Marchac, Alexandre; Benjoar, Marc David; Hivelin, Mikael; Lantieri, Laurent

2018-06-02

 The volume of the profunda femoris artery perforator (PAP) flap limits its indications to small- and medium-sized breast reconstructions after modified radical mastectomy for cancer. We report a modified PAP flap design, including not only a vertical extension that increases its volume but also the skin surface, which suits larger breasts requiring immediate or delayed breast reconstructions and compare the results with our horizontal skin paddle PAP flap experience.  In our center between November 2014 and November 2016, 51 consecutive patients underwent a PAP flap breast reconstruction following breast cancer. A retrospective analysis on the collected data was performed to compare 34 patients with a bra cup smaller than C who underwent 41 horizontal PAP flap procedures, with those ( n  = 17) of a bra cup greater than or equal to C who underwent 21 fleur-de-lys PAP flap procedures. Demographic, anthropometric, flap and surgical characteristics, postoperative complication rates, and hospital stay were compared between the two groups.  The average flap weight was 480 g (range: 340-735 g) for the fleur-de-lys PAP flap group compared with 222 g (range: 187-325 g) for the horizontal PAP flap procedure ( p  < 0.001). The mean flap dimensions were 25 × 18 cm for the fleur-de-lys PAP flap group compared with 25 × 7 cm in the horizontal PAP flap group. No flap failure was observed in the fleur-de-lys PAP flap group compared with two flap failures secondary to venous thrombosis in the horizontal PAP flap group ( NS ). Three patients (14%) experienced delayed healing at the donor site compared with four patients (10%) in the horizontal PAP flap group ( NS ).  The fleur-de-lys skin paddle design not only allows an increase of the horizontal PAP flap volume, but also increases the skin surface, with an acceptable donor site morbidity. For medium- or large-sized breasts, the fleur-de-lys PAP flap seems to be ideal when a DIEP flap

Clinical applications of perforator-based propeller flaps in upper limb soft tissue reconstruction.

PubMed

Ono, Shimpei; Sebastin, Sandeep J; Yazaki, Naoya; Hyakusoku, Hiko; Chung, Kevin C

2011-05-01

A propeller flap is an island flap that moves from one orientation to another by rotating around its vascular axis. The vascular axis is stationary, and flap movement is achieved by revolving on this axis. Early propeller flaps relied on a thick, subcutaneous pedicle to maintain vascularity, and this limited the flap rotation to 90°. With increasing awareness of the location and the vascular territory perfused by cutaneous perforators, it is now possible to design propeller flaps based on a single perforator, so-called "perforator-based propeller flaps." These flaps permit flap rotation up to 180°. We present the results of upper limb soft tissue reconstruction using perforator-based propeller flaps. We constructed a treatment strategy based on the location of the soft tissue defect and the perforator anatomy for expedient wound coverage in 1 stage. All perforator-based propeller flaps derived from 3 institutions that were used for upper limb soft tissue reconstruction were retrospectively analyzed. The parameters studied included the size and location of the defect, the perforator that was used, the size and shape of the flap, the direction (ie, clockwise or counter-clockwise) of flap rotation, the degree of twisting of the perforator, the management of the donor site (ie, linear closure or skin grafting), and flap survival (recorded as the percentage of the flap area that survived). Twelve perforator-based propeller flaps were used to reconstruct upper limb soft tissue defects in 12 patients. Six different perforators were used as vascular pedicles. The donor defects of 11 flaps could be closed primarily. One flap was partially lost in a patient with electrical burns. Perforator-based propeller flaps provide a reliable option for covering small- to medium-size upper limb soft tissue defects. Copyright © 2011 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

50 CFR Figure 16 to Part 223 - Escape Opening and Flap Dimensions for the Double Cover Flap TED

Code of Federal Regulations, 2012 CFR

2012-10-01

... 50 Wildlife and Fisheries 10 2012-10-01 2012-10-01 false Escape Opening and Flap Dimensions for the Double Cover Flap TED 16 Figure 16 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED...

Vascularized osseous flaps and assessing their bipartate perfusion pattern via intraoperative fluorescence angiography.

PubMed

Valerio, Ian; Green, J Marshall; Sacks, Justin M; Thomas, Shane; Sabino, Jennifer; Acarturk, T Oguz

2015-01-01

Large segmental bone and composite tissue defects often require vascularized osseous flaps for definitive reconstruction. However, failed osseous flaps due to inadequate perfusion can lead to significant morbidity. Utilization of indocyanine green (ICG) fluorescence angiography has been previously shown to reliably assess soft tissue perfusion. Our group will outline the application of this useful intraoperative tool in evaluating the perfusion of vascularized osseous flaps. A retrospective review was performed to identify those osseous and/or osteocutaneous bone flaps, where ICG angiography was employed. Data analyzed included flap types, success and failure rates, and perfusion-related complications. All osseous flaps were evaluated by ICG angiography to confirm periosteal and endosteal perfusion. Overall 16 osseous free flaps utilizing intraoperative ICG angiography to assess vascularized osseous constructs were performed over a 3-year period. The flaps consisted of the following: nine osteocutaneous fibulas, two osseous-only fibulas, two scapular/parascapular with scapula bone, two quadricep-based muscle flaps, containing a vascularized femoral bone component, and one osteocutaneous fibula revision. All flap reconstructions were successful with the only perfusion-related complication being a case of delayed partial skin flap loss. Intraoperative fluorescence angiography is a useful adjunctive tool that can aid in flap design through angiosome mapping and can also assess flap perfusion, vascular pedicle flow, tissue perfusion before flap harvest, and flap perfusion after flap inset. Our group has successfully extended the application of this intraoperative tool to assess vascularized osseous flaps in an effort to reduce adverse outcomes related to preventable perfusion-related complications. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Perforator flap based on the third perforator of the profunda femoris artery (PFA)-assisted closure of the free vertical posteromedial thigh (vPMT) flap donor site.

PubMed

Scaglioni, Mario F; Barth, Andrè A; Chen, Yen-Chou

2018-06-19

The primary closure of the vertical posteromedial thigh (vPMT) free flap donor site is very important to minimize donor site morbidity and maximize cosmetic appearance. However, sometimes due to the dimension of the defect, a vPMT flap is wider than the 8-10 cm requirement. The authors report their experience with the third perforator of the profunda femoris artery (PFA) during the vPMT free flap donor-site closure. Between January 2016 and December 2017, 5 patients underwent reconstruction of lower extremity (2 pts.) and head and neck (3 pts.) area with the free vPMT flaps. Attempts to close the vPMT free flap donor site directly failed due to the flaps' width (average: 11 cm) and pedicled perforator flaps based on the third perforator of the PFA at the distal thigh were harvested to close the defect primary without the use of a skin graft. The size of perforator flap based on 3rd perforator of PFA was on average 6 cm × 4 cm (ranged: 4-8 cm × 3-6 cm). In all patients, the third perforator of the PFA was identified and the perforator diameter was on average 2.0 mm (range, 1.8-2.2 mm). All perforators were musculocutaneous and single. The dimensions of the flaps were on average 6 cm × 4 cm (range: 4 to 8 cm × 3 to 6 cm). All flaps healed uneventfully without complications and the patients were satisfied with cosmetic and functional results at 6 months follow-up. The third perforator of the PFA may be an option to ensure primary closure of the PMT flap donor site, when a larger flap for reconstruction is needed with subsequent impossibility to achieve primary closure of the donor site. © 2018 Wiley Periodicals, Inc.

Single-molecule FRET unveils induced-fit mechanism for substrate selectivity in flap endonuclease 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rashid, Fahad; Harris, Paul D.; Zaher, Manal S.

Human flap endonuclease 1 (FEN1) and related structure-specific 5’nucleases precisely identify and incise aberrant DNA structures during replication, repair and recombination to avoid genomic instability. Yet, it is unclear how the 5’nuclease mechanisms of DNA distortion and protein ordering robustly mediate efficient and accurate substrate recognition and catalytic selectivity. Here, single-molecule sub-millisecond and millisecond analyses of FEN1 reveal a protein-DNA induced-fit mechanism that efficiently verifies substrate and suppresses off-target cleavage. FEN1 sculpts DNA with diffusion-limited kinetics to test DNA substrate. This DNA distortion mutually ‘locks’ protein and DNA conformation and enables substrate verification with extreme precision. Strikingly, FEN1 never missesmore » cleavage of its cognate substrate while blocking probable formation of catalytically competent interactions with noncognate substrates and fostering their pre-incision dissociation. These findings establish FEN1 has practically perfect precision and that separate control of induced-fit substrate recognition sets up the catalytic selectivity of the nuclease active site for genome stability.« less

Single-molecule FRET unveils induced-fit mechanism for substrate selectivity in flap endonuclease 1

DOE PAGES

Rashid, Fahad; Harris, Paul D.; Zaher, Manal S.; ...

2017-02-23

Human flap endonuclease 1 (FEN1) and related structure-specific 5’nucleases precisely identify and incise aberrant DNA structures during replication, repair and recombination to avoid genomic instability. Yet, it is unclear how the 5’nuclease mechanisms of DNA distortion and protein ordering robustly mediate efficient and accurate substrate recognition and catalytic selectivity. Here, single-molecule sub-millisecond and millisecond analyses of FEN1 reveal a protein-DNA induced-fit mechanism that efficiently verifies substrate and suppresses off-target cleavage. FEN1 sculpts DNA with diffusion-limited kinetics to test DNA substrate. This DNA distortion mutually ‘locks’ protein and DNA conformation and enables substrate verification with extreme precision. Strikingly, FEN1 never missesmore » cleavage of its cognate substrate while blocking probable formation of catalytically competent interactions with noncognate substrates and fostering their pre-incision dissociation. These findings establish FEN1 has practically perfect precision and that separate control of induced-fit substrate recognition sets up the catalytic selectivity of the nuclease active site for genome stability.« less

Single-molecule FRET unveils induced-fit mechanism for substrate selectivity in flap endonuclease 1

PubMed Central

Rashid, Fahad; Harris, Paul D; Zaher, Manal S; Sobhy, Mohamed A; Joudeh, Luay I; Yan, Chunli; Piwonski, Hubert; Tsutakawa, Susan E; Ivanov, Ivaylo; Tainer, John A; Habuchi, Satoshi; Hamdan, Samir M

2017-01-01

Human flap endonuclease 1 (FEN1) and related structure-specific 5’nucleases precisely identify and incise aberrant DNA structures during replication, repair and recombination to avoid genomic instability. Yet, it is unclear how the 5’nuclease mechanisms of DNA distortion and protein ordering robustly mediate efficient and accurate substrate recognition and catalytic selectivity. Here, single-molecule sub-millisecond and millisecond analyses of FEN1 reveal a protein-DNA induced-fit mechanism that efficiently verifies substrate and suppresses off-target cleavage. FEN1 sculpts DNA with diffusion-limited kinetics to test DNA substrate. This DNA distortion mutually ‘locks’ protein and DNA conformation and enables substrate verification with extreme precision. Strikingly, FEN1 never misses cleavage of its cognate substrate while blocking probable formation of catalytically competent interactions with noncognate substrates and fostering their pre-incision dissociation. These findings establish FEN1 has practically perfect precision and that separate control of induced-fit substrate recognition sets up the catalytic selectivity of the nuclease active site for genome stability. DOI: http://dx.doi.org/10.7554/eLife.21884.001 PMID:28230529

Reconstruction of the vulva with sensate gluteal fold flaps.

PubMed

Kuokkanen, H; Mikkola, A; Nyberg, R H; Vuento, M H; Kaartinen, I; Kuoppala, T

2013-01-01

Soft-tissue reconstruction of the vulva following resection of malignancies is challenging. The function of perineal organs should be preserved and the reconstructed area should maintain an acceptable cosmetic appearance. Reconstruction with local flaps is usually sufficient in the primary phase after a radical vulvectomy. Numerous flaps have been designed for vulvar reconstruction usually based on circulation from the internal pudendal artery branches. In this paper we introduce our modification of the gluteal fold V-Y advancement flap as a primary reconstruction after a radical vulvectomy. Twenty-two patients were operated with a radical vulvectomy because of vulvar malignancies. The operation was primary in eight and secondary in 14 patients. The reconstruction of the vulva was performed in the same operation for each patient. All flaps survived completely. Wound complications were registered in three patients. Late problems with urinary stream were corrected in two patients. A local recurrence of the malignancy was observed in six patients during the follow-up period. Gluteal fold flap is easy to perform, has a low rate of complications and gives good functional results. Even a large defect can be reconstructed reliably with this method. A gluteal fold V-Y advancement flap is sensate and our modification allows the flap to be transposed with lesser dissection as presented before.

Reverse-flow retroauricular island flap in facial reconstruction.

PubMed

Benlier, Erol; Top, Husamettin; Cinar, Can; Yazar, Sukru; Aygit, A Cemal; Cetinkale, Oguz

2007-12-01

Reconstruction of facial skin defects requires good-quality skin cover to satisfy aesthetic expectations of patient, especially when the skin defect is on the uncovered area of the face. Limitations in the available local tissue and donor-site morbidity restrict the options. In an effort to solve these problems, we have begun to use a subcutaneous pedicled retroauricular reverse-flow flap. Between January 1997 and December 2005, reverse-flow subcutaneous pedicled retroauricular island flap was used to cover facial defects in 12 patients who underwent surgical excision of skin tumor. The patients ranged in age from 44 to 81 years with a mean age of 58 years. Only one case experienced a superficial necrosis in the distal one-quarter part of the flap. The functional and aesthetic results were satisfactory for both patients and surgeons, and no tumor recurrence was observed during the 12 to 28 months (mean, 18.8 months) follow-up period. This flap can be used reliably for the reconstruction of facial skin defects of small and medium size. The preference of frontal branch pedicled flap enables more distal facial area defects to be covered, such as dorsal nasal, nasolabial, and upper lip, than flaps based on parietal branch.

FAMM Flap in Reconstructing Postsurgical Nasopharyngeal Airway Stenosis

PubMed Central

Nangole, Ferdinand Wanjala; Khainga, Stanley Ominde

2014-01-01

Introduction. Postsurgical nasopharyngeal airway stenosis can be a challenge to manage. The stenosis could be as a result of any surgical procedure in the nasopharyngeal region that heals extensive scarring and fibrosis. Objective. To evaluate patients with nasopharyngeal stenosis managed with FAMM flap. Study Design. Prospective study of patients with nasopharyngeal stenosis at the Kenyatta National Hospital between 2010 and 2013 managed with FAMM flap. Materials and Methods. Patients with severe nasopharyngeal airway stenosis were reviewed and managed with FAMM flaps at the Kenyatta National Hospital. Postoperatively they were assessed for symptomatic improvement in respiratory distress, patency of the nasopharyngeal airway, and donor site morbidity. Results. A total of 8 patients were managed by the authors in a duration of 4 years with nasopharyngeal stenosis. Five patients were managed with unilateral FAMM flaps in a two-staged surgical procedure. Four patients had complete relieve of the airway obstruction with a patent airway created. One patient had a patent airway created though with only mild improvement in airway obstruction. Conclusion. FAMM flap provides an alternative in the management of postsurgical severe nasopharyngeal stenosis. It is a reliable flap that is easy to raise and could provide adequate epithelium for the stenosed pharynx. PMID:25328699

Piloted simulation study of two tilt-wing flap control concepts, phase 2

NASA Technical Reports Server (NTRS)

Birckelbaw, Lourdes G.; Corliss, Lloyd D.; Hindson, William S.; Churchill, Gary B.

1994-01-01

A two phase piloted simulation study has been conducted in the Ames Vertical Motion Simulator to investigate alternative wing and flap controls for tilt-wing aircraft. This report documents the flying qualities results and findings of the second phase of the piloted simulation study and describes the simulated tilt-wing aircraft, the flap control concepts, the experiment design and the evaluation tasks. The initial phase of the study compared the flying qualities of both a conventional programmed flap and an innovative geared flap. The second phase of the study introduced an alternate method of pilot control for the geared flap and further studied the flying qualities of the programmed flap and two geared flap configurations. In general, the pilot ratings showed little variation between the programmed flap and the geared flap control concepts. Some differences between the two control concepts were noticed and are discussed in this report. The geared flap configurations had very similar results. Although the geared flap concept has the potential to reduce or eliminate the pitch control power requirements from a tail rotor or a tail thruster at low speeds and in hover, the results did not show reduced tail thruster pitch control power usage with the geared flap configurations compared to the programmed flap configuration. The addition of pitch attitude stabilization in the second phase of simulation study greatly enhanced the aircraft flying qualities compared to the first phase.

Interchain hydrophobic clustering promotes rigidity in HIV-1 protease flap dynamics: new insights from molecular dynamics.

PubMed

Meher, Biswa Ranjan; Kumar, Mattaparthi Venkata Satish; Bandyopadhyay, Pradipta

2014-01-01

The dynamics of HIV-1 protease (HIV-pr), a drug target for HIV infection, has been studied extensively by both computational and experimental methods. The flap dynamics of HIV-pr is considered to be more important for better ligand binding and enzymatic actions. Moreover, it has been demonstrated that the drug-induced mutations can change the flap dynamics of HIV-pr affecting the binding affinity of the ligands. Therefore, detailed understanding of flap dynamics is essential for designing better inhibitors. Previous computational investigations observed significant variation in the flap opening in nanosecond time scale indicating that the dynamics is highly sensitive to the simulation protocols. To understand the sensitivity of the flap dynamics on the force field and simulation protocol, molecular dynamics simulations of HIV-pr have been performed with two different AMBER force fields, ff99 and ff02. Two different trajectories (20 ns each) were obtained using the ff99 and ff02 force field. The results showed polarizable force field (ff02) make the flap tighter than the nonpolarizable force field (ff99). Some polar interactions and hydrogen bonds involving flap residues were found to be stronger with ff02 force field. The formation of interchain hydrophobic cluster (between flap tip of one chain and active site wall of another chain) was found to be dominant in the semi-open structures obtained from the simulations irrespective of the force field. It is proposed that an inhibitor, which will promote this interchain hydrophobic clustering, may make the flaps more rigid, and presumably the effect of mutation would be small on ligand binding.

Bed isolation in experimental flap studies in rats: a dispensable procedure.

PubMed

Heimer, Sina; Schaefer, Amelia; Mueller, Wolf; Lass, Ulrike; Gebhard, Martha M; Germann, Günter; Leimer, Uwe; Köllensperger, Eva; Reichenberger, Matthias A

2013-03-01

Review of the literature regarding rodent experimental flap models reveals fundamental differences in applied surgical procedures. Although some authors isolate the flap from its wound bed, others do not. This study was planned to investigate to what extent the insertion of a silicone sheet affects physiological wound healing in experimental flap surgery. An extended epigastric adipocutaneous flap (6 × 10 cm) was raised in 16 male Lewis rats. In the control group (group C), flaps were immediately inset without any intervention. In the experimental group (group M), a silicone sheet barrier was placed between the flap and the wound bed. Mean flap survival area and flap perfusion were evaluated. Microvessel density was visualized by immunohistochemistry, and semiquantitative real-time polymerase chain reaction addressed differential gene expression. All animals were investigated on postoperative day 5. Flap survival area and flap perfusion were found to be similar. Immunohistochemistry, however, demonstrated a significantly increased number of CD31-positive small vessels in group C. The insertion of the silicone sheet barrier (group M) was accompanied by a significantly enhanced expression of proinflammatory genes and a suppression of proangiogenic genes. Our results show that although the silicone membrane has no influence on the surgical outcome in terms of flap survival and perfusion, it does lead to significant molecular alterations in pathways involved in physiological wound healing. These alterations are artificially induced by the foreign body material and conceal the true driving forces of the healing process. As the latter might include relevant therapeutic targets to ameliorate surgical results, we regard wound bed isolation as a dispensable procedure in the study of rodent flap models.

Works on theory of flapping wing. [considering boundary layer

NASA Technical Reports Server (NTRS)

Golubev, V. V.

1980-01-01

It is shown mathematically that taking account of the boundary layer is the only way to develop a theory of flapping wings without violating the basic observations and mathematics of hydromechanics. A theory of thrust generation by flapping wings can be developed if the conventional downstream velocity discontinuity surface is replaced with the observed Karman type vortex streets behind a flapping wing. Experiments show that the direction of such vortices is the reverse of that of conventional Karman streets. The streets form by breakdown of the boundary layer. Detailed analysis of the movements of certain birds and insects during flight 'in place' is fully consistent with this theory of the lift, thrust and drag of flapping wings. Further directions for research into flight with flapping wings are indicated.

Reconstruction of lower face defect or deformity with submental artery perforator flaps.

PubMed

Shi, Cheng-li; Wang, Xian-cheng

2012-07-01

Reconstruction of lower face defects or deformity often presents as a challenge for plastic surgeons. Many methods, including skin graft, tissue expander, or free flap are introduced. Submental artery perforator flaps have been used in the reconstruction of defects or deformities of the lower face. Between August 2006 and December 2008, 22 patients with lower face defects or deformity underwent reconstruction with pedicled submental artery perforator flaps. Their age ranged between 14 and 36 years. The perforator arteries were detected and labeled with a hand-held Doppler flowmeter. The size of flaps ranged from 4 × 6 to 6 × 7 cm, and the designed flaps included the perforator artery. All the flaps survived well, except 1 flap which resulted in partial necrosis in distal region and healed after conservative therapy. No other complication occurred with satisfactory aesthetic appearance of the donor site. The submental artery perforator flap is a thin and reliable flap with robust blood supply. This flap can reduce donor-site morbidity significantly and is a good choice for reconstructive surgery of lower face.

50 CFR Figure 16 to Part 223 - Escape Opening and Flap Dimensions for the Double Cover Flap TED

Code of Federal Regulations, 2011 CFR

2011-10-01

... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Escape Opening and Flap Dimensions for the Double Cover Flap TED 16 Figure 16 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE...

A dynamical system for interacting flapping swimmers

NASA Astrophysics Data System (ADS)

Oza, Anand; Ramananarivo, Sophie; Ristroph, Leif; Shelley, Michael

2015-11-01

We present the results of a theoretical investigation into the dynamics of interacting flapping swimmers. Our study is motivated by the recent experiments of Becker et al., who studied a one-dimensional array of self-propelled flapping wings that swim within each other's wakes in a water tank. They discovered that the system adopts certain ``schooling modes'' characterized by specific spatial phase relationships between swimmers. To rationalize these phenomena, we develop a discrete dynamical system in which the swimmers are modeled as heaving airfoils that shed point vortices during each flapping cycle. We then apply our model to recent experiments in the Applied Math Lab, in which two tandem flapping airfoils are free to choose both their speed and relative positions. We expect that our model may be used to understand how schooling behavior is influenced by hydrodynamics in more general contexts. Thanks to the NSF for its support.

14 CFR 23.699 - Wing flap position indicator.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.699 Wing flap position indicator. There must be a wing flap position...

14 CFR 23.699 - Wing flap position indicator.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.699 Wing flap position indicator. There must be a wing flap position...

14 CFR 23.699 - Wing flap position indicator.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.699 Wing flap position indicator. There must be a wing flap position...

14 CFR 23.699 - Wing flap position indicator.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.699 Wing flap position indicator. There must be a wing flap position...

Treatment of ischial pressure sores with double adipofascial turnover flaps.

PubMed

Lin, Haodong; Hou, Chunlin; Xu, Zhen; Chen, Aiming

2010-01-01

Despite a variety of flap reconstruction options, the ischium remains the most difficult pressure sore site to treat. This article describes the authors' successful surgical procedure for coverage of ischial ulcers using double adipofascial turnover flaps.After debridement, the adipofascial flaps are harvested both cephalad and caudal to the defect. The flaps are then turned over to cover the exposed bone in a manner so as to overlap the 2 flaps. The skin is then closed with sutures in 2 layers. A total of 15 patients with ischial sores were treated using this surgical procedure.The follow-up period ranged from 11 to 159 months, with a mean of 93.6 months. Overall, 86.7% of the flaps (13 of 15) healed primarily. One patient had a recurrent grade II ischial pressure sore again 11 months after the operation. The other 14 patients did not have a recurrence.Treatment of ischial pressure sores with adipofascial turnover flaps provides an easy, minimally invasive procedure, with preservation of future flap options, and a soft-tissue supply sufficient for covering the bony prominence and filling dead space. This technique is a reliable and safe reconstructive modality for the management of minor ischial pressure sores.

Porcine experimental model for perforator flap raising in reconstructive microsurgery.

PubMed

González-García, José A; Chiesa-Estomba, Carlos M; Álvarez, Leire; Altuna, Xabier; García-Iza, Leire; Thomas, Izaskun; Sistiaga, Jon A; Larruscain, Ekhiñe

2018-07-01

Perforator free flap-based reconstruction of the head and neck is a challenging surgical procedure and needs a steep learning curve. A reproducible mammal large animal model with similarities to human anatomy is relevant for perforator flap raising and microanastomosis. The aim of this study was to assess the feasibility of a swine model for perforator-based free flaps in reconstructive microsurgery. Eleven procedures were performed under general anesthesia in a porcine model, elevating a skin flap vascularized by perforating musculocutaneous branches of the superior epigastric artery to evaluate the relevance of this model for head and neck reconstructive microsurgery. The anterior abdominal skin perforator-based free flap in a swine model irrigated by the superior epigastric artery was elevated in eleven procedures. In six of these procedures, we could perform an arterial and venous microanastomosis to the great vessels located in the base of the neck. The porcine experimental model of superior epigastric artery perforator-based free flap reconstruction offers relevant similarities to the human deep inferior epigastric artery perforator flap. We could demonstrate this model as acceptable for perforator free flap training due to the necessity of perforator and pedicle dissection and transfer to a distant area. Copyright © 2018 Elsevier Inc. All rights reserved.

A lining vomer flap for palate pushback in unilateral cleft palate repair.

PubMed

Clavin, H D; Owsley, J Q

1978-01-01

A combinaation vomer mucoperiosteal flap and nasal floor mucoperiosteal flap is described which is used to achieve nasal coverage in unilateral cleft palate patients requiring pushbacks. A posteriorly based readily accessible vomer flap is raised on the cleft side and used as nasal lining for the palatal mucoperiosteal flap on the non-cleft side. On the cleft side, a symmetrically sized nasal floor flap is easily elevated under direct vision and used to cover the nasal aspect of the corresponding mucoperiosteal palatal flap.

Dynamic perfusion assessment during perforator flap surgery: an up-to-date

PubMed Central

MUNTEAN, MAXIMILIAN VLAD; MUNTEAN, VALENTIN; ARDELEAN, FILIP; GEORGESCU, ALEXANDRU

2015-01-01

Flap monitoring technology has progressed alongside flap design. The highly variable vascular anatomy and the complexity associated with modern perforator flaps demands dynamic, real-time, intraoperative information about the vessel location, perfusion patterns and flap physiology. Although most surgeons still assess flap perfusion and viability based solely on clinical experience, studies have shown that results may be highly variable and often misleading. Poor judgment of intraoperative perfusion leads to major complications. Employing dynamic perfusion imaging during flap reconstruction has led to a reduced complication rate, lower morbidity, shorter hospital stay, and an overall better result. With the emergence of multiple systems capable of intraoperative flap evaluation, the purpose of this article is to review the two systems that have been widely accepted and are currently used by plastic surgeons: Indocyanine green angiography (ICGA) and dynamic infrared thermography (DIRT). PMID:26609259

Tracheal reconstruction with a pleuroperiosteal flap.

PubMed

Krespi, Y P; Biller, H F; Baek, S M

1983-12-01

Reconstruction of extensive tracheal defects remains a difficult surgical problem. In many experiments restoration of tracheal mucosa by autogenous or homologous soft tissue grafts has usually failed because of rejection or tracheal obstruction. This experimental work employed a two-stage surgical procedure that allowed reconstruction of extensive circumferential full-thickness defects of the trachea. Stage I involved the creation of a vascularized pleuroperiosteal flap that was formed into a rigid tube around a Silastic stent. Stage II consisted of creation of a full-thickness circumferential tracheal defect and repair with the flap in those animals in which a suitable rigid tube had been formed. The results of these experiments argue strongly that a vascularized composite pleuroperiosteal flap can produce an adequate tracheal replacement.

Posttraumatic eyebrow reconstruction with hair-bearing temporoparietal fascia flap

PubMed Central

Denadai, Rafael; Raposo-Amaral, Cassio Eduardo; Marques, Frederico Figueiredo; Raposo-Amaral, Cesar Augusto

2015-01-01

The temporoparietal fascia flap has been extensively used in craniofacial reconstructions. However, its use for eyebrow reconstruction has been sporadically reported. We describe a successfully repaired hair-bearing temporoparietal fascia flap after traumatic avulsion of eyebrow. Temporoparietal fascia flap is a versatile tool and should be considered as a therapeutic option by all plastic surgeons. PMID:25993077

Dynamic response of a piezoelectric flapping wing

NASA Astrophysics Data System (ADS)

Kumar, Alok; Khandwekar, Gaurang; Venkatesh, S.; Mahapatra, D. R.; Dutta, S.

2015-03-01

Piezo-composite membranes have advantages over motorized flapping where frequencies are high and certain coupling between bending and twisting is useful to generate lift and forward flight. We draw examples of fruit fly and bumble bee. Wings with Piezo ceramic PZT coating are realized. The passive mechanical response of the wing is characterized experimentally and validated using finite element simulation. Piezoelectric actuation with uniform electrode coating is characterized and optimal frequencies for flapping are identified. The experimental data are used in an empirical model and advanced ratio for a flapping insect like condition for various angular orientations is estimated.

Wind tunnel test of a tailless aircraft with a belly-flap control surface used in combination with wing flaps

NASA Astrophysics Data System (ADS)

Dougherty, Daniel A.

A wind tunnel tat of a tailless aircraft configuration that has been quipped with a belly-flap control surface, was conducted with the goal of improving the trimmed maximum-lift coefficient. Tailless aircraft have aerodynamic and structural efficiencies that are superior to those of a traditionally configured wing/body/tail aircraft. However, tailless aircraft have a low maximum-lift coefficient such that; when sized for equivalent takeoff performance, the tailless aircraft suffers a large reduction in aerodynamic and structural efficiencies. A Belly-Flap control surface used in combination with wing trailing edge flaps was tested in a wind tunnel with the goal of achieving a longitudinally trimmed solution at a higher maximum lift coefficient. It was determined that, though the Belly-Flap increases the trimmed lift of the tailless configuration at low angles of attack, the maximum lift coefficient is slightly reduced in relation to the controls neutral configuration.

Vortex Flap Technology: a Stability and Control Assessment

NASA Technical Reports Server (NTRS)

Carey, K. M.; Erickson, G. E.

1984-01-01

A comprehensive low-speed wind tunnel investigation was performed of leading edge vortex flaps applied to representative aircraft configurations. A determination was made of the effects of analytically- and empirically-designed vortex flaps on the static longitudinal and lateral-directional aerodynamics, stability, and control characteristics of fighter wings having leading-edge sweep angles of 45 to 76.5 degrees. The sensitivity to several configuration modifications was assessed, which included the effects of flap planform, leading- and trailing-edge flap deflection angles, wing location on the fuselage, forebody strakes, canards, and centerline and outboard vertical tails. Six-component forces and moments, wing surface static pressure distributions, and surface flow patterns were obtained using the Northrop 21- by 30-inch low-speed wind tunnel.

Freestyle multiple propeller flap reconstruction (jigsaw puzzle approach) for complicated back defects.

PubMed

Park, Sung Woo; Oh, Tae Suk; Eom, Jin Sup; Sun, Yoon Chi; Suh, Hyun Suk; Hong, Joon Pio

2015-05-01

The reconstruction of the posterior trunk remains to be a challenge as defects can be extensive, with deep dead space, and fixation devices exposed. Our goal was to achieve a tension-free closure for complex defects on the posterior trunk. From August 2006 to May 2013, 18 cases were reconstructed with multiple flaps combining perforator(s) and local skin flaps. The reconstructions were performed using freestyle approach. Starting with propeller flap(s) in single or multilobed design and sequentially in conjunction with adjacent random pattern flaps such as fitting puzzle. All defects achieved tensionless primary closure. The final appearance resembled a jigsaw puzzle-like appearance. The average size of defect was 139.6 cm(2) (range, 36-345 cm(2)). A total of 26 perforator flaps were used in addition to 19 random pattern flaps for 18 cases. In all cases, a single perforator was used for each propeller flap. The defect and the donor site all achieved tension-free closure. The reconstruction was 100% successful without flap loss. One case of late infection was noted at 12 months after surgery. Using multiple lobe designed propeller flaps in conjunction with random pattern flaps in a freestyle approach, resembling putting a jigsaw puzzle together, we can achieve a tension-free closure by distributing the tension to multiple flaps, supplying sufficient volume to obliterate dead space, and have reliable vascularity as the flaps do not need to be oversized. This can be a viable approach to reconstruct extensive defects on the posterior trunk. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Improvement of Tissue Survival of Skin Flaps by 5α-Reductase Inhibitors: Possible Involvement of Nitric Oxide and Inducible Nitric Oxide Synthase

PubMed Central

Karimi, Ali Asghar; Ajami, Marjan; Asadi, Yasin; Aboutaleb, Nahid; Gorjipour, Fazel; Malekloo, Roya; Pazoki-Toroudi, Hamidreza

2015-01-01

Background: Skin flap grafting is a popular approach for reconstruction of critical skin and underlying soft tissue injuries. In a previous study, we demonstrated the beneficial effects of two 5α-reductase inhibitors, azelaic acid and finasteride, on tissue survival in a rat model of skin flap grafting. In the current study, we investigated the involvement of nitric oxide and inducible nitric oxide synthase (iNOS) in graft survival mediated by these agents. Methods: A number of 42 male rats were randomly allocated into six groups: 1, normal saline topical application; 2, azelaic acid (100 mg/flap); 3, finasteride (1 mg/flap); 4, injection of L-NG-nitroarginine methyl ester (L-NAME) (i.p., 20 mg/kg); 5, L-NAME (20 mg/kg, i.p.) + azelaic acid (100 mg/flap, topical); 6, L-NAME (20 mg/kg, i.p.) + finasteride (1 mg/flap, topical). Tissue survival, level of nitric oxide, and iNOS expression in groups were measured. Results: Our data revealed that azelaic acid and finasteride significantly increased the expression of iNOS protein and nitric oxide (NO) levels in graft tissue (P < 0.05). These increases in iNOS expression and NO level were associated with higher survival of the graft tissue. Conclusion: It appears that alterations of the NO metabolism are implicated in the azelaic acid- and finasteride-mediated survival of the skin flaps. PMID:25864816

USB noise reduction by nozzle and flap modifications

NASA Technical Reports Server (NTRS)

Hayden, R. E.

1976-01-01

The development of concepts for reducing upper surface blown flap noise at the source through flap modifications and special nozzles is reviewed. In particular, recent results obtained on the aerodynamic and acoustic performance of flaps with porous surfaces near the trailing edge and multi-slotted nozzles are reviewed. Considerable reduction (6-10 db) of the characteristic low frequency peak is shown. The aerodynamic performance is compared with conventional systems, and prospects for future improvements are discussed.

Pressure Distribution Over a Symmetrical Airfoil Section with Trailing Edge Flap

NASA Technical Reports Server (NTRS)

Jacobs, Eastman N; Pinkerton, Robert M

1931-01-01

Measurements were made to determine the distribution of pressure over one section of an R. A. F. 30 (symmetrical) airfoil with trailing edge flaps. In order to study the effect of scale measurements were made with air densities of approximately 1 and 20 atmospheres. Isometric diagrams of pressure distribution are given to show the effect of change in incidence, flap displacement, and scale upon the distribution. Plots of normal force coefficient versus angle of attack for different flap displacements are given to show the effect of a displaced flap. Plots are given of both the experimental and theoretical characteristic coefficients versus flap angle, in order to provide a comparison with the theory. It is concluded that for small flap displacements the agreement for the pitching and hinge moments is such that it warrants the use of the theoretical parameters. However, the agreement for the lift is not as good, particularly for the smaller flaps. In an appendix, an example is given of the calculation of the load and moments on an airfoil with hinged flap from these parameters.

Reconstruction of trochanteric pressure sores with pedicled anterolateral thigh myocutaneous flaps.

PubMed

Wang, Chih-Hsin; Chen, Shih-Yi; Fu, Ju-Peng; Dai, Niann-Tzyy; Chen, Shao-Liang; Chen, Tim-Mo; Chen, Shyi-Gen

2011-05-01

To provide an alternative choice for covering trochanteric pressure sores, we report on a modified pedicle anterolateral thigh (ALT) myocutaneous flap based on the descending branch of the lateral circumflex femoral artery. From August 2007 to January 2010, 20 consecutive patients (10 men and 10 women) underwent 21 pedicled ALT myocutaneous flaps for reconstruction of trochanteric pressure sores. The flap was designed and elevated, resembling the ALT perforator flap including part of the vastus lateralis muscle but without skeletonisation of the perforators. The mean age of patients was 79.4 years (range: 46-103). The mean follow-up period was 13.9 months (range: 3-32). The flaps were 8-21 cm long and 5-11 cm wide. All flaps healed without major complications. All donor sites were closed primarily without skin grafting and showed good aesthetic results. No recurrence was observed. This modified design of pedicled ALT myocutaneous flap without skeletonisation of perforators is a reliable and easily harvested flap for reconstruction of trochanteric pressure sores with limited morbidity. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

Intercostal artery perforator propeller flap for reconstruction of trunk defects following sarcoma resection.

PubMed

Zang, Mengqing; Yu, Shengji; Xu, Libin; Zhao, Zhenguo; Zhu, Shan; Ding, Qiang; Liu, Yuanbo

2015-06-01

Trunk defects following soft tissue sarcoma resection are usually managed by myocutaneous flaps or free flaps. However, harvesting muscle will cause functional morbidities and some trunk regions lack reliable recipient vessels. The intercostal arteries give off multiple perforators, which distribute widely over the trunk and can supply various pedicle flaps. Our purpose is to use various intercostal artery perforator propeller flaps for trunk oncologic reconstruction. Between November 2013 and July 2014, nine intercostal artery perforator propeller flaps were performed in seven patients to reconstruct the defects following sarcoma resection in different regions of the trunk, including the back, lumbar, chest, and abdomen. Two perforators from intercostal arteries were identified for each flap using Doppler ultrasound probe adjacent to the defect. The perforator with visible pulsation was chosen as the pedicle vessel. An elliptical flap was raised and rotated in a propeller fashion to repair the defects. There were one dorsal intercostal artery perforator flap, four dorsolateral intercostal artery perforator flaps, three lateral intercostal artery perforator flaps, and one anterior intercostal artery perforator flap. The mean skin paddle dimension was 9.38 cm in width (range 6-14 cm) and 21.22 cm in length (range 13-28 cm). All intercostal artery perforator flaps survived completely, except for marginal necrosis in one flap harvested close to the previous flap donor site. The intercostal artery perforator propeller flap provides various and valuable options in our reconstructive armamentarium for trunk oncologic reconstruction. To our knowledge, this is the first case series of using intercostal artery perforator propeller flaps for trunk oncologic reconstruction and clinical application of dorsolateral intercostal artery perforator flaps. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All

Free anterolateral thigh flap for reconstruction of major craniofacial defects.

PubMed

Amin, Ayman; Rifaat, Mohammed; Civantos, Francisco; Weed, Donald; Abu-Sedira, Mohammed; Bassiouny, Mahmoud

2006-02-01

Free-tissue transfer has revolutionized skull-base surgery by expanding the ability to perform cranial base resection and by improving the quality of reconstruction. The anterolateral thigh flap has come recently into use in the field of head and neck reconstruction. Its role in craniofacial and midface reconstruction has not been specifically defined. This study involved a total of 18 patients who were treated over a 5-year period from 1998 to 2003. Seventeen patients had locally advanced head and neck cancer, requiring craniofacial resection, and one patient had a complicated gun shot wound of the forehead. Thirteen patients were treated at the National Cancer Institute, Cairo University, Egypt, and five patients at the University of Miami, Florida. The patients presented with defects of the anterior skull base (5), lateral skull base (3), scalp and calvarium (3), and the midface (7). The anterolateral thigh flap was used as a myocutaneous flap in 11 cases and as a perforator fasciocutaneous flap in seven cases. Musculocutaneous perforators supplied the majority of flaps (17/18). Total flap survival occurred in 17 cases; one patient developed complete flap necrosis. The most commonly used recipient vessels were the facial vessels and the external jugular vein. Major complications included one case with meningitis; the patient died after failure of treatment. Another patient died 6 weeks postoperatively from pulmonary embolism. One patient developed CSF leak that stopped spontaneously. In addition, two patients developed minor wound dehiscence that healed spontaneously. The donor-site wound healed without problems except in two cases. One patient had an incomplete take of the skin graft; the other developed wound infection and superficial sloughing. Both wounds healed spontaneously. In addition to the feasibility of simultaneous flap harvesting with tumor resection, the flap's advantage in skull base reconstruction is its reliable blood supply, which can provide

Proline Scanning Mutagenesis Reveals a Role for the Flap Endonuclease-1 Helical Cap in Substrate Unpairing*

PubMed Central

Patel, Nikesh; Exell, Jack C.; Jardine, Emma; Ombler, Ben; Finger, L. David; Ciani, Barbara; Grasby, Jane A.

2013-01-01

The prototypical 5′-nuclease, flap endonuclease-1 (FEN1), catalyzes the essential removal of single-stranded flaps during DNA replication and repair. FEN1 hydrolyzes a specific phosphodiester bond one nucleotide into double-stranded DNA. This specificity arises from double nucleotide unpairing that places the scissile phosphate diester on active site divalent metal ions. Also related to FEN1 specificity is the helical arch, through which 5′-flaps, but not continuous DNAs, can thread. The arch contains basic residues (Lys-93 and Arg-100 in human FEN1 (hFEN1)) that are conserved by all 5′-nucleases and a cap region only present in enzymes that process DNAs with 5′ termini. Proline mutations (L97P, L111P, L130P) were introduced into the hFEN1 helical arch. Each mutation was severely detrimental to reaction. However, all proteins were at least as stable as wild-type (WT) hFEN1 and bound substrate with comparable affinity. Moreover, all mutants produced complexes with 5′-biotinylated substrate that, when captured with streptavidin, were resistant to challenge with competitor DNA. Removal of both conserved basic residues (K93A/R100A) was no more detrimental to reaction than the single mutation R100A, but much less severe than L97P. The ability of protein-Ca2+ to rearrange 2-aminopurine-containing substrates was monitored by low energy CD. Although L97P and K93A/R100A retained the ability to unpair substrates, the cap mutants L111P and L130P did not. Taken together, these data challenge current assumptions related to 5′-nuclease family mechanism. Conserved basic amino acids are not required for double nucleotide unpairing and appear to act cooperatively, whereas the helical cap plays an unexpected role in hFEN1-substrate rearrangement. PMID:24126913

Supraclavicular artery perforator flap in management of post-burn neck reconstruction: clinical experience

PubMed Central

Ismail, H.; Elshobaky, A.

2016-01-01

Summary Anterior cervical contractures of the neck represent a great challenge for plastic and reconstructive surgeons. Necks can be reconstructed with a wide range of surgical techniques, including chimeric flaps, supercharged flap, pre-expanded flaps, “superthin” flaps and perforator flaps. The supraclavicular flap is easy to harvest without the need for free tissue transfer. It provides a relatively large flap for neck resurfacing with tissue very similar to that of the neck. Between January 2013 and March 2015, 20 patients suffering from postburn neck contracture underwent reconstruction with 20 unilateral supraclavicular artery perforator flaps. Nineteen patients had post-burn neck contractures (9 cases type Іc, 10 cases type Пc) while only one had post-burn granulation tissue in the neck. We harvested fifteen flaps from the right side and five from the left. Size of the reconstructed defect ranged from 23x10 to14x6, and flap size varied from 25/11 to 16/7cm. Period of follow up ranged from 27-2months (average 12.3). Nineteen flaps survived well (95% survival rate): only one was lost due to iatrogenic extensive dissection over the pedicle. Five cases showed distal superficial epidermolysis, and 2 cases showed 2 cm complete distal necrosis. All patients were managed conservatively. Our results coincide with other literature results confirming the efficacy and rich vascularity of this flap. In all cases with distal partial necrosis, flaps were 23 cm or more. We recommend that supraclavicular flaps of more than 22 cm in length are not harvested immediately and that flaps are expanded before harvesting. Expanding the supraclavicular flap increases its surface area and decreases donor site morbidity. PMID:28149252

Viscous investigation of a flapping foil propulsor

NASA Astrophysics Data System (ADS)

Posri, Attapol; Phoemsapthawee, Surasak; Thaweewat, Nonthipat

2018-01-01

Inspired by how fishes propel themselves, a flapping-foil device is invented as an alternative propulsion system for ships and boats. The performance of such propulsor has been formerly investigated using a potential flow code. The simulation results have shown that the device has high propulsive efficiency over a wide range of operation. However, the potential flow gives good results only when flow separation is not present. In case of high flapping frequency, the flow separation can occur over a short instant due to fluid viscosity and high angle of attack. This may cause a reduction of propulsive efficiency. A commercial CFD code based on Lattice Boltzmann Method, XFlow, is then employed in order to investigate the viscous effect over the propulsive performance of the flapping foil. The viscous results agree well with the potential flow results, confirming the high efficiency of the propulsor. As expected, viscous results show lower efficiency in high flapping frequency zone.

Perforator-based propeller flaps for leg reconstruction in pediatric patients.

PubMed

Özalp, Burhan; Aydınol, Mustafa

2016-10-01

Perforator-based propeller flaps provide adequate soft tissue coverage for leg reconstruction. The aim of this study was to assess the versatility and reliability of the use of propeller flaps for leg reconstruction in pediatric patients. Seven male pediatric patients ranging in age from 2 to 13 years with a mean age of 6.7 underwent perforator-based propeller flap surgery over a four-year period. The defects resulted from burn injuries (n = 4) and traffic accidents (n = 3). The injuries were located on the ankles of four patients and on the knee, anterior lower tibia, and foot dorsum of the other three patients, respectively. The flap sizes ranged from 5 × 3 to 10 × 6 cm with a mean flap size of 7.6 × 4.3 cm. Flap harvesting time ranged from 38 to 56 m with a mean of 46 m. The rotation degree range of the flaps was from 90° to 180°. The propeller flaps were based on the posterior tibial artery (n = 4), anterior tibial artery (n = 2), and the descending branch of the lateral circumflex femoral artery (n = 1). All flaps survived completely without surgical complication; however, one patient developed disseminated intravascular coagulation syndrome two days post-surgery and died within four days. Perforator-based propeller flap reconstruction is a safe, reliable, and versatile method for lower extremities in pediatric patients; however, it requires meticulous surgical dissection and extreme patience during the surgical procedure. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Improving Pressure Ulcer Reconstruction: Our Protocol and the COP (Cone of Pressure) Flap

PubMed Central

Edstrom, Lee; Szymanski, Karen; Schmidt, Scott; Bevivino, Jack; Zienowicz, Richard; Stark, Jennifer; Taylor, Helena O.; Podda, Silvio; Liu, Paul

2017-01-01

Background: Surgical treatment of pressure ulcers is challenging for high recurrence rates. Deepithelialized flaps have been used previously with the aim to eliminate shearing forces and the cone of pressure (COP) effect. The goal of this study is to adopt a standardized protocol and evaluate if 2 different flap techniques affect outcomes. Methods: The novel COP flap is illustrated. Twenty patients were prospectively treated with flap coverage over a 36-month period. According to the flap type, patients were assigned to 2 groups: group 1 with 11 patients treated with the COP flap and group 2 with 9 patients treated with conventional flap without anchoring technique. We adopted a standardized protocol of debridement, tissue cultures, and negative-pressure wound therapy. Rotation fasciocutaneous flaps were used for both groups and mean follow-up was 19 months. The COP flap is a large deepithelialized rotation flap inset with transcutaneous nonabsorbable bolster sutures. The 2 groups were comparable for demographics and ulcer location and size (P < 0.05). Five patients showed positive cultures and were treated with antibiotics and negative-pressure therapy before surgery. Results: Recurrence rates were 12% in the COP flap group and 60% in the conventional flap coverage group (P < 0.001). Results were compared at 16-month follow-up. Conclusions: The COP flap significantly reduces recurrences and eliminates shearing forces, suture ripping, and tension on superficial soft-tissue layers. The technique can be applied to both ischial and sacral pressure sores. The flap provides padding over bony prominence without jeopardizing flap vascularity. PMID:28458961

A new agent for flap survival – Hippophae rhamnoides L. (sea buckthorn): An experimental study in rats

PubMed Central

Emsen, Ilteris Murat

2005-01-01

Hippophae rhamnoides L. (sea buckthorn) is a member of the Elaeagnaceae family, and is a temperate bush native to Europe and Asia. The antioxidant activity of H rhamnoides L. has been shown in vitro cell culture and animal studies. Different fractions of H rhamnoides L. fruits inhibit 2,2-azobis-(2,4 dimethylvaleronitrile) and ascorbate iron-induced lipid peroxidations in vitro. H rhamnoides L., as well as vitamin E, decrease the malondialdehyde content in hyperlipidemic rabbit serum-cultured smooth muscle cells. The aim of the present study was to investigate, in a rat model, the potential effect of H rhamnoides L. on survival of random pattern skin flaps. For this purpose, 30 Wistar Albino rats were used, and a McFarlane-type caudally based skin flap was created on the dorsum of the rat (2.5 cm × 8 cm). Rats were divided into three groups: one control (group A) and two treatment groups (groups B and C). H rhamnoides L. was administered orally to the experimental groups: group B received a single 15 mg/kg dose per day and group C received 15 mg/kg twice per day. The areas and lengths of flap necrosis were measured in each group. The extent of necrotic flap areas were evaluated as length and area of total flap area, and differences were studied by Student’s t tests. The areas and lengths of necrosis of skin flaps decreased depending on H rhamnoides L., but viability of the flaps treated with 15 mg/kg/day was not significantly different from the control group. The rats receiving H rhamnoides L. 15 mg/kg twice per day had the highest flap survival rate (P<0.001). In conclusion, H rhamnoides L. may have a dose-dependent effect to increase flap survival in random skin flaps. PMID:24227931

Free radial forearm adiposo-fascial flap for inferior maxillectomy defect reconstruction

PubMed Central

Thankappan, Krishnakumar; Trivedi, Nirav P.; Sharma, Mohit; Kuriakose, Moni A.; Iyer, Subramania

2009-01-01

A free radial forearm fascial flap has been described for intraoral reconstruction. Adiposo-fascial flap harvesting involves few technical modifications from the conventional radial forearm fascio-cutaneous free flap harvesting. We report a case of inferior maxillectomy defect reconstruction in a 42-year-old male with a free radial forearm adiposo-fascial flap with good aesthetic and functional outcome with minimal primary and donor site morbidity. The technique of raising the flap and closing the donor site needs to be meticulous in order to achieve good cosmetic and functional outcome. PMID:19881028

50 CFR Figure 16 to Part 223 - Escape Opening and Flap Dimensions for the Double Cover Flap TED

Code of Federal Regulations, 2010 CFR

2010-10-01

... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Escape Opening and Flap Dimensions for the Double Cover Flap TED 16 Figure 16 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE AND ANADROMOUS SPECIES Pt. 223, Fig. 1...

[Reconstruction of facial soft tissue defects with pedicled expanded flaps].

PubMed

Yangqun, Li; Yong, Tang; Wen, Chen; Zhe, Yang; Muxin, Zhao; Lisi, Xu; Chunmei, Hu; Yuanyuan, Liu; Ning, Ma; Jun, Feng; Weixin, Wang

2014-09-01

To investigate the application of pedicled expanded flaps for the reconstruction of facial soft tissue defects. The expanded skin flaps, pedicled with orbicularis oculi muscle, submental artery, the branch of facial artery, superficial temporal artery, interior upper arm artery, had similar texture and color as facial soft tissue. The pedicled expanded flaps have repaired the facial soft tissue defects. Between Jan. 2003 to Dec. 2013, 157 cases with facial soft tissue defects were reconstructed by pedicled expanded flaps. Epidermal necrosis happened at the distal end of 8 expanded flaps, pedicled with interior upper arm artery(4 cases), orbicularis oculi muscle(3 cases) and submental artery(1 case), which healed spontaneously after dressing. All the other flaps survived completely with similar color and inconspicuous scar. 112 cases were followed up for 8 months to 8 years. Satisfactory results were achieved in 75 cases. 37 cases with hypertrophic scar at incisions need secondary operation. Island pedicled expanded flap with similar texture and color as facial soft tissue is suitable for facial soft tissue defects. The facial extra-incision and large dog-ear deformity could be avoided.

The Differential Use of Bilobed and Trilobed Transposition Flaps in Cutaneous Nasal Reconstructive Surgery.

PubMed

Knackstedt, Thomas; Lee, Kachiu; Jellinek, Nathaniel J

2018-05-22

Bilobed and trilobed transposition flaps are versatile random pattern transposition flaps which reliably restore nasal symmetry, topography, light reflex, contour and are frequently used in cutaneous nasal reconstructive surgery. We wish to compare the characteristics of bilobed and trilobed flaps in cutaneous reconstructive surgery and to identify scenarios for their differential use. A retrospective chart review over 7 years of consecutive patients reconstructed with a bilobed or trilobed flap after Mohs micrographic surgery was performed. Statistical analysis of patient and surgery characteristics, anatomic distribution, postprocedural events and need for revisions after both flap types was conducted. One hundred eleven patients with bilobed flaps and 74 patients with trilobed flaps were identified. Bilobed flaps are significantly more frequently used on the inferior nasal dorsum and on the sidewall whereas trilobed flaps are significantly more frequently used on the nasal tip and infratip. No significant difference in postprocedural events (complications, erythema, trapdoor, etc) was noted between the two flap types. Bilobed and trilobed transposition flaps are versatile repairs for nasal reconstruction. Trilobed flaps may be used to repair defects in a more distal nasal location than bilobed flaps. Regardless of flap type, complications are rare.

The Arterialized Facial Artery Musculo-Mucosal Island Flap for Post-Oncological Tongue Reconstruction.

PubMed

Moro, Alessandro; Saponaro, Gianmarco; Doneddu, Piero; Cervelli, Daniele; Pelo, Sandro; Gasparini, Giulio; Garagiola, Umberto; D'Amato, Giuseppe; Todaro, Mattia

2018-05-15

In 1992, Pribaz described the facial artery musculomucosal flap (FAMM), an axial musculomucosal flap based on the facial artery. The FAMM flap, a modification of the nasolabial and buccal mucosal flaps, is widely used in the reconstruction of defects in the oral cavity. Many modifications of this flap have been described in the literature. Here we aimed to explore the use of an arterialized tunnelized FAMM island flap (a-FAMMIF) for the reconstruction tongue defects after tumor resection. From January 2015 to December 2016, five cases of tongue cancer were selected for the use of arterialized FAMMIF flap to reconstruct defects after tumor resection. Reconstruction was successful in all cases, except one case of total flap necrosis; partial necrosis of the flap occurred in two patients, which were solved with medications. The authors consider the a-FAMMIF an unreliable flap in the reconstruction of tongue defects.The authors recommend avoiding tunneling and island modification when the vein is not included in the pedicle.

Near-Infrared Irradiation Increases Length of Axial Pattern Flap Survival in Rats.

PubMed

Yasunaga, Yoshichika; Matsuo, Kiyoshi; Tanaka, Yohei; Yuzuriha, Shunsuke

2017-01-01

Objective: We previously reported that near-infrared irradiation nonthermally induces long-lasting vasodilation of the subdermal plexus by causing apoptosis of vascular smooth muscle cells. To clarify the possible application of near-infrared irradiation to prevent skin flap necrosis, we evaluated the length of axial pattern flap survival in rats by near-infrared irradiation. Methods: A bilaterally symmetric island skin flap was elevated under the panniculus carnosus on the rat dorsum. Half of the flap was subjected to near-infrared irradiation just before flap elevation with a device that simulates solar radiation, which has a specialized contact cooling apparatus to avoid thermal effects. The length of flap survival of the near-infrared irradiated side was measured 7 days after flap elevation and compared with the nonirradiated side. Results: The irradiated side showed elongation of flap survival compared with the nonirradiated side (73.3 ± 11.7 mm vs 67.3 ± 14.9 mm, respectively, P = .03). Conclusions: Near-infrared irradiation increases the survival length of axial pattern flaps in rats.

Propeller Flaps: A Review of Indications, Technique, and Results

PubMed Central

D'Arpa, Salvatore; Toia, Francesca; Pirrello, Roberto; Moschella, Francesco; Cordova, Adriana

2014-01-01

In the last years, propeller flaps have become an appealing option for coverage of a large range of defects. Besides having a more reliable vascular pedicle than traditional flap, propeller flaps allow for great freedom in design and for wide mobilization that extend the possibility of reconstructing difficult wounds with local tissues and minimal donor-site morbidity. They also allow one-stage reconstruction of defects that usually require multiple procedures. Harvesting of a propeller flap requires accurate patient selection, preoperative planning, and dissection technique. Complication rate can be kept low, provided that potential problems are prevented, promptly recognized, and adequately treated. This paper reviews current knowledge on propeller flaps. Definition, classification, and indications in the different body regions are discussed based on a review of the literature and on the authors' experience. Details about surgical technique are provided, together with tips to avoid and manage complications. PMID:24971367

Optimization of the Flapping Wing Systems for Micro Air Vehicle

DTIC Science & Technology

2010-09-01

as 87%, under specific combinations of the flapping kinematics by water tunnel experiments [5]. Pesavento and Wang found that optimized flapping wing...41-72. [6] Pesavento , U., and Wang Z. J., “Flapping Wing Flight Can Save Aerodynamic Power Compared to Steady Flight,” Physical Review Letters

The plane problem of the flapping wing

NASA Technical Reports Server (NTRS)

Birnbaum, Walter

1954-01-01

In connection with an earlier report on the lifting vortex sheet which forms the basis of the following investigations this will show how the methods developed there are also suitable for dealing with the air forces for a wing with a circulation variable with time. The theory of a propulsive wing flapping up and down periodically in the manner of a bird's wing is developed. This study shows how the lift and its moment result as a function of the flapping motion, what thrust is attainable, and how high is the degree of efficiency of this flapping propulsion unit if the air friction is disregarded.

Vulva reconstruction after pelvic exenteration, using a unique combination of two flaps

PubMed Central

van Bommel, Annelotte C M; Schreuder, Henk W R; Schellekens, Pascal P A

2011-01-01

A 64-year-old woman with recurrence of carcinoma of the vulva in an irradiated area received an en-bloc total pelvic exenteration. Reconstruction of the pelvic defect was performed with an anterolateral thigh (ALT) flap and a rectus abdominis muscle (RAM) flap (PM/RAM). This combination of flaps is unique, with excellent results. In a large defect, often irradiated in advance, well-vascularised tissue should be placed. Multiple flaps can be used to reconstruct these large pelvic defects, each with their own advantages and disadvantages. The combination of flaps used in this case uses the good properties of both flaps: the reliable and well-vascularised PM/RAM in combination with the ALT flap to provide much bulk in extreme large defects. PMID:22692483

Early experience with the free lumbar artery perforator flap for breast reconstruction.

PubMed

Peters, Kevin T; Blondeel, Phillip N; Lobo, Fernando; van Landuyt, Koenraad

2015-08-01

Autologous breast reconstruction has become a progressively more popular method of breast reconstruction. A wide variety of perforator flaps have been described and subsequently refined to decrease donor-site morbidity. Recently, the lumbar artery perforator (LAP) flap has been reported as an option for autologous breast reconstruction. This study summarises the prospectively gathered data of 35 free LAP flaps for breast reconstruction in 28 patients. The mean follow-up was 18 months. The internal mammary artery and the venae comitantes were used as recipient vessels in all reconstructions. In 80% of the reconstructions (28 flaps), an interposition graft was used. Six flaps (17%) had to be revised for venous thrombosis. Two of the revised flaps (5.7%) could not be salvaged, and total flap necrosis occurred. The mean operating time was 6 h and 15 min, 6 h and 39 min when an interposition graft was used and 5 h and 23 min when no interposition graft was necessary. The LAP flap should be considered as a further alternative for breast reconstruction in patients in whom a deep inferior epigastric artery perforator (DIEAP) flap is not possible or not desirable. Shaping of this flap is easier compared to any other flaps due to the quality of the lumbar fat and the gluteal extension. An interposition graft is frequently used to facilitate anastomosis, either to lengthen the pedicle or to resolve size mismatch. This is a disadvantage of the LAP flap. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Wound Healing and Angiogenesis through Combined Use of a Vascularized Tissue Flap and Adipose-Derived Stem Cells in a Rat Hindlimb Irradiated Ischemia Model.

PubMed

Yoshida, Shuhei; Yoshimoto, Hiroshi; Hirano, Akiyoshi; Akita, Sadanori

2016-05-01

Treatment of critical limb ischemia is sometimes difficult because of the patient's condition, and some novel approaches are needed. The hindlimbs of Sprague-Dawley rats, after 20-Gy x-ray irradiation and surgical occlusion, were divided into four groups: with a superficial fascial flap, 5.0 × 10 adipose-derived stromal/stem cells, and both combined. The rats were tested for laser tissue blood flow, immunohistologic blood vessel density, and foot paw punch hole wound healing. Green fluorescent protein-tagged Sprague-Dawley rats were used for further investigation by cell tracking for 2 weeks. Laser tissue blood flow demonstrated a significant increase in the combined treatment of flap and adipose-derived stem cells at both 1 and 2 weeks. There were no significant differences between the treatment groups treated with flaps alone and those treated with adipose-derived stem cells alone. Wound healing was significantly increased following combined treatment at 1 week, and there was no wound by 2 weeks except for the no-flap and no-adipose-derived stem cell group. The number of vessels depicted by von Willebrand factor showed a significant increase in the combined treatment group, at both 1 week and 2 weeks. In the cell tracking group, at 2 weeks, the green fluorescent protein-tagged adipose-derived stem cells were significantly more positive in the no-flap group than in the flap group. Adipose-derived stem cells may be a potent cell source in irradiated and occluded limbs by enhancing tissue blood flow and blood vessel density. Adipose-derived stem cells may play an important role in some difficult ischemic conditions in terms of wound healing.

Why borrow from Peter when Paul can afford it? Reverse homodigital artery flap for fingertip reconstruction

PubMed Central

Sundaramurthy, Narayanamurthy; Venkata Mahipathy, Surya Rao Rao; Durairaj, Alagar Raja

2017-01-01

Background: Fingertip injuries that are complicated by pulp loss, bone or tendon exposure will need a flap cover. Cross finger flap is commonly used to cover such defects. However, patients are apprehensive about injuring the uninjured finger as a donor site. Reverse homodigital artery flap (RHAF) can provide reliable vascularised cover to such defects. Aims: This study aims to assess the functional and aesthetic outcomes along with the patient satisfaction of RHAFs done for fingertip defects. Materials and Methods: RHAFs done in 18 patients operated between August 2015 and October 2016 were retrospectively analysed on flap survival, sensory recovery, range of movements, hypersensitivity, cold intolerance, flexion contracture and donor site morbidity. Results: Seventeen of the 18 flaps done survived completely. One flap had partial necrosis of 3 mm that healed conservatively. Middle finger of the right hand was the most commonly injured finger. Touch, pain and pressure sensations recovered in 8–12 weeks. Two-point discrimination was 4.5 mm at 6 months. The deficit of 5° s was present at distal interphalangeal joint during active flexion at 6 months. Cold intolerance and flexion contracture were not seen and 2 instances of hypersensitivity at 2 months got cured conservatively after 4 months. Overall satisfaction of patients was 8/10. Conclusion: RHAF provides single staged well-vascularised cover for fingertip injuries with good sensory recovery without damaging the adjacent uninjured finger. Hence, it can be a reliable flap for fingertip reconstruction in selected cases. PMID:29343895

Comparison of Laser Doppler and Laser-Assisted Indocyanine Green Angiography Prediction of Flap Survival in a Novel Modification of the McFarlane Flap.

PubMed

Fourman, Mitchell Stephen; Gersch, Robert P; Phillips, Brett T; Nasser, Ahmed; Rivara, Andrew; Verma, Richa; Dagum, Alexander B; Rosengart, Todd K; Bui, Duc T

2015-07-01

The McFarlane rat ischemic dorsal skin flap model has been commonly used for clinical vector studies, as well as the testing of noninvasive diagnostics. However, variability of this model secondary to flap contact with the wound bed has led many to question its validity. Here we present a novel modification to the McFarlane skin flap using sterile silicone. We also use this model to test the prognostic efficacy of laser-assisted indocyanine green (ICG) angiography and laser Doppler imaging (LDI). A 3 × 9-cm dorsal skin flap with a cranially based pedicle was created, centered 1 cm distal to the scapulae. The flap was undermined, and in one of the 2 groups, a sterile silicone sheet was placed onto the wound bed. All flaps were then reapproximated with sutures 1-cm intervals. Clinical assessment and perfusion imaging was performed immediately postoperative, and at 24, 48, and 72 hours postsurgery. Postoperative day 7 clinical assessment was obtained before euthanasia. A comparative study using silicone blocked versus unblocked models (n = 6 per group) showed that, clinically, both models had equivalent flap survival [8.5 (0.913) vs 9.5 (1.01) cm]. However, a statistically significant increase in perfusion in the mid-third of unblocked models was observed on POD3 [20.28% (2.7%) vs blocked 13.45% (2.5%), P < 0.05], with a similar increase in the distal third on POD7 [18.73% (2.064%) vs 10.91% (4.19%), P < 0.05]. A prognostic study comparing LDI and ICG angiography prediction of POD7 survival at early time points (n = 10) found that LDI underpredicted flap survival at early time points [84.2% (12.03%) on POD0, 87.35% (16.11%) on POD1]. In contrast, ICG was more proficient [100.1% (10.1%) on POD0]. We present a modification of the McFarlane skin flap model that results in similar clinical results, but with a noted reduction in perfusion inconsistencies noted in unblocked models. The ICG angiography is superior to LDI in predicting POD7 flap necrosis within the first 48

The shunt from the cyclooxygenase to lipoxygenase pathway in human osteoarthritic subchondral osteoblasts is linked with a variable expression of the 5-lipoxygenase-activating protein.

PubMed

Maxis, Kelitha; Delalandre, Aline; Martel-Pelletier, Johanne; Pelletier, Jean-Pierre; Duval, Nicolas; Lajeunesse, Daniel

2006-01-01

Osteoarthritis (OA) is characterized by articular cartilage degradation and hypertrophic bone changes with osteophyte formation and abnormal bone remodeling. Two groups of OA patients were identified via the production of variable and opposite levels of prostaglandin E2 (PGE2) or leukotriene B4 (LTB4) by subchondral osteoblasts, PGE2 levels discriminating between low and high subgroups. We studied whether the expression of 5-lipoxygenase (5-LO) or 5-LO-activating protein (FLAP) is responsible for the shunt from prostaglandins to leukotrienes. FLAP mRNA levels varied in low and high OA groups compared with normal, whereas mRNA levels of 5-LO were similar in all osteoblasts. Selective inhibition of cyclooxygenase-2 (COX-2) with NS-398-stimulated FLAP expression in the high OA osteoblasts subgroup, whereas it was without effect in the low OA osteoblasts subgroup. The addition of PGE2 to the low OA osteoblasts subgroup decreased FLAP expression but failed to affect it in the high OA osteoblasts subgroup. LTB4 levels in OA osteoblasts were stimulated about twofold by 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) plus transforming growth factor-beta (TGF-beta), a situation corresponding to their effect on FLAP mRNA levels. Treatments with 1,25(OH)2D3 and TGF-beta also modulated PGE2 production. TGF-beta stimulated PGE2 production in both OA osteoblast groups, whereas 1,25(OH)2D3 alone had a limited effect but decreased the effect of TGF-beta in the low OA osteoblasts subgroup. This modulation of PGE2 production was mirrored by the synthesis of COX-2. IL-18 levels were only slightly increased in a subgroup of OA osteoblasts compared with normal; however, no relationship was observed overall between IL-18 and PGE2 levels in normal and OA osteoblasts. These results suggest that the shunt from the production of PGE2 to LTB4 is through regulation of the expression of FLAP, not 5-LO, in OA osteoblasts. The expression of FLAP in OA osteoblasts is also modulated differently by 1,25(OH

Facial artery musculomucosal flap for reconstruction of skull base defects: a cadaveric study.

PubMed

Xie, Liyue; Lavigne, François; Rahal, Akram; Moubayed, Sami Pierre; Ayad, Tareck

2013-08-01

Failure in skull base defects reconstruction following tumor resection can have serious consequences such as ascending meningitis and pneumocephaly. The nasoseptal flap showed a very low incidence of cerebrospinal fluid leak but is not always available. The superiorly pedicled facial artery musculomucosal (FAMM) flap has been successfully used for reconstruction of head and neck defects. Our objective is to show that the FAMM flap can be used as a new alternative in skull base reconstruction. Cadaveric study. Feasibility. Thirteen specimens underwent bilateral FAMM flap dissection. Two new modifications of the traditional FAMM flap have been developed. Feasibility in FAMM flap transfer to the skull base was investigated through endoscopic skull base dissection and maxillectomy in four specimens. Measurements were recorded for each harvested flap. The mean surface area of the modified FAMM flap efficient for reconstruction was 15.90 cm(2) . The flaps easily covered the simulated defects of the frontal sinus and the fovea ethmoidalis areas. Modifications of the traditional FAMM flap were necessary for a tension-free coverage of the planum sphenoidale and sella turcica. The FAMM flap holds high potential as a new alternative vascular flap in skull base reconstruction. However, it has not been used in patients yet and should be considered only when other options are not available. New modifications developed in this article can elongate the traditional FAMM flap, potentially contributing to a tighter seal of the skull base defect than FAMM flap alone. © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

Biochemical and Cellular Assessment of Acetabular Chondral Flaps Identified During Hip Arthroscopy.

PubMed

Hariri, Sanaz; Truntzer, Jeremy; Smith, Robert Lane; Safran, Marc R

2015-06-01

To analyze chondral flaps debrided during hip arthroscopy to determine their biochemical and cellular composition. Thirty-one full-thickness acetabular chondral flaps were collected during hip arthroscopy. Biochemical analysis was undertaken in 21 flaps from 20 patients, and cellular viability was determined in 10 flaps from 10 patients. Biochemical analysis included concentrations of (1) DNA (an indicator of chondrocyte content), (2) hydroxyproline (an indicator of collagen content), and (3) glycosaminoglycan (an indicator of chondrocyte biosynthesis). Higher values for these parameters indicated more healthy tissue. The flaps were examined to determine the percentage of viable chondrocytes. The percentage of acetabular chondral flap specimens that had concentrations within 1 SD of the mean values reported in previous normal cartilage studies was 38% for DNA, 0% for glycosaminoglycan, and 43% for hydroxyproline. The average cellular viability of our acetabular chondral flap specimens was 39% (SD, 14%). Only 2 of the 10 specimens had more than half the cells still viable. There was no correlation between (1) the gross examination of the joint or knowledge of the patient's demographic characteristics and symptoms and (2) biochemical properties and cell viability of the flap, with one exception: a degenerative appearance of the surrounding cartilage correlated with a higher hydroxyproline concentration. Although full-thickness acetabular chondral flaps can appear normal grossly, the biochemical properties and percentage of live chondrocytes in full-thickness chondral flaps encountered in hip arthroscopy show that this tissue is not normal. There has been recent interest in repairing chondral flaps encountered during hip arthroscopy. These data suggest that acetabular chondral flaps are not biochemically and cellularly normal. Although these flaps may still be valuable mechanically and/or as a scaffold in some conductive or inductive capacity, further study is

LASIK flap buttonhole treated immediately by PRK with mitomycin C.

PubMed

Kymionis, George D; Portaliou, Dimitra M; Karavitaki, Alexandra E; Krasia, Maria S; Kontadakis, Georgios A; Stratos, Aimilianos; Yoo, Sonia H

2010-03-01

To describe the visual outcomes of three patients who had LASIK flap buttonhole and were treated immediately with photorefractive keratectomy (PRK) and topical mitomycin C (MMC) 0.02%. Three patients underwent bilateral LASIK with the SCHWIND Carriazo-Pendula 90 microm head microkeratome. In all three cases, a buttonhole flap occurred in the left eye. The flap was repositioned and phototherapeutic keratectomy for 50 microm was used for epithelial removal while immediate PRK with MMC was performed to treat the buttonhole flap. Three months after the procedure, uncorrected distance visual acuity and corrected distance visual acuity were 20/20 with regular topographic findings. Using PRK with MCC immediately after the occurrence of the LASIK flap buttonhole may be an effective treatment.

Study of Flapping Flight Using Discrete Vortex Method Based Simulations

NASA Astrophysics Data System (ADS)

Devranjan, S.; Jalikop, Shreyas V.; Sreenivas, K. R.

2013-12-01

In recent times, research in the area of flapping flight has attracted renewed interest with an endeavor to use this mechanism in Micro Air vehicles (MAVs). For a sustained and high-endurance flight, having larger payload carrying capacity we need to identify a simple and efficient flapping-kinematics. In this paper, we have used flow visualizations and Discrete Vortex Method (DVM) based simulations for the study of flapping flight. Our results highlight that simple flapping kinematics with down-stroke period (tD) shorter than the upstroke period (tU) would produce a sustained lift. We have identified optimal asymmetry ratio (Ar = tD/tU), for which flapping-wings will produce maximum lift and find that introducing optimal wing flexibility will further enhances the lift.

Full-Scale Wind-Tunnel Investigation of a Jet Flap in Conjunction with a Plain Flap with Blowing Boundary-Layer Control on a 35 deg Sweptback-Wing Airplane

NASA Technical Reports Server (NTRS)

Aoyagi, Kiyoshi; Hickey, David H.

1959-01-01

Previous investigations have shown that increased blowing at the hinge-line radius of a plain flap will give flap lift increases above that realized with boundary-layer control. Other experiments and theory have shown that blowing from a wing trailing edge, through the jet flap effect, produced lift increases. The present investigation was made to determine whether blowing simultaneously at the hinge-line radius and trailing edge would be more effective than blowing separately at either location. The tests were made at a Reynolds number of 4.5 x 10(exp 6) with a 35 deg sweptback-wing airplane. For this report, only the lift data are presented. Of the three flap blowing arrangements tested, blowing distributed between the trailing edge and the hinge-line radius of a plain flap was found to be superior to blowing at either location separately at the plain flap deflections of interest. Comparison of estimated and experimental jet flap effectiveness was fair.

Noise reduction tests of large-scale-model externally blown flap using trailing-edge blowing and partial flap slot covering. [jet aircraft noise reduction

NASA Technical Reports Server (NTRS)

Mckinzie, D. J., Jr.; Burns, R. J.; Wagner, J. M.

1976-01-01

Noise data were obtained with a large-scale cold-flow model of a two-flap, under-the-wing, externally blown flap proposed for use on future STOL aircraft. The noise suppression effectiveness of locating a slot conical nozzle at the trailing edge of the second flap and of applying partial covers to the slots between the wing and flaps was evaluated. Overall-sound-pressure-level reductions of 5 db occurred below the wing in the flyover plane. Existing models of several noise sources were applied to the test results. The resulting analytical relation compares favorably with the test data. The noise source mechanisms were analyzed and are discussed.

A new skin flap method for total auricular reconstruction in microtia patients with a reconstructed ear canal: extended scalp and extended mastoid postauricular skin flaps.

PubMed

Hwang, Euna; Kim, Young Soo; Chung, Seum

2014-06-01

Before visiting a plastic surgeon, some microtia patients may undergo canaloplasty for hearing improvement. In such cases, scarred tissues and the reconstructed external auditory canal in the postauricular area may cause a significant limitation in using the posterior auricular skin flap for ear reconstruction. In this article, we present a new method for auricular reconstruction in microtia patients with previous canaloplasty. By dividing a postauricular skin flap into an upper scalp extended skin flap and a lower mastoid extended skin flap at the level of a reconstructed external auditory canal, the entire anterior surface of the auricular framework can be covered with the two extended postauricular skin flaps. The reconstructed ear shows good color match and texture, with the entire anterior surface of the reconstructed ear being resurfaced with the skin flaps. Clinical question/level of evidence; therapeutic level IV. Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Preoperative color Doppler assessment in planning of gluteal perforator flaps.

PubMed

Isken, Tonguc; Alagoz, M Sahin; Onyedi, Murat; Izmirli, Hakki; Isil, Eda; Yurtseven, Nagehan

2009-02-01

Gluteal artery perforator flaps have gained popularity due to reliability, preservation of the muscle, versatility in flap design without restricting other flap options, and low donor-site morbidity in ambulatory patients and possibility of enabling future reconstruction in paraplegic patients. But the inconstant anatomy of the vascular plexus around the gluteal muscle makes it hard to predict how many perforators are present, what their volume of blood flow and size are, where they exit the overlying fascia, and what their course through the muscle will be. Without any prior investigations, the reconstructive surgeon could be surprised intraoperatively by previous surgical damage, scar formation, or anatomic variants.For these reasons, to confirm the presence and the location of gluteal perforators preoperatively we have used color Doppler ultrasonography. With the help of the color Doppler ultrasonography 26 patients, 21 men and 5 women, were operated between the years 2002 and 2007. The mean age of patients was 47.7 (age range: 7-77 years). All perforator vessels were marked preoperatively around the defect locations. The perforator based flap that will allow primary closure of the donor site and the defect without tension was planned choosing the perforator that showed the largest flow in color Doppler ultrasonography proximally. Perforators were found in the sites identified with color Doppler ultrasonography in all other flaps. In our study, 94.4% flap viability was ensured in 36 perforator-based gluteal area flaps. Mean flap elevation time was 31.9 minutes. We found that locating the perforators preoperatively helps to shorten the operation time without compromising a reliable viability of the perforator flaps, thus enabling the surgeon easier treatment of pressure sores.

Design and construction of an airfoil with controlled flap

NASA Astrophysics Data System (ADS)

Amin, Md. Ruhul; Rahman, S. M. Mahbobur; Mashud, Mohammad; Rabbi, Md. Fazle

2017-06-01

For modern aircrafts maneuvering control and reduction of power loss is a matter of great concern in Aerodynamics. Separation of airflow over the wings of aircraft at high angle of attack or at other situations is a hindrance to proper maneuvering control. As flow separation increases drag force on the aircraft, it consumes excess power. For these reasons much effort and research has gone into the design of aerodynamic surfaces which delay flow separation and keep the local flow attached for as long as possible. One of the simple and cost-effective way is to use a hinged flap on the wing of the aircraft, which lifts and self-adjusts to a position dependent on the aerodynamic forces and flap weight due to reversed flow at increasing angle of attack. There is a limitation of this kind of process. At very high angles of attack, the reversed flow would cause the flap to tip forwards entirely and the effect of the flap would vanish. For recovering this limitation an idea of controlling the movement or rotation of the flap has been proposed in this paper. A light surface was selected as a flap and was coupled to the shaft of a servo motor, which was placed on a model airfoil. For controlling the angle of rotation of the motor as well as the flap arbitrarily, an electronic circuit comprising necessary components was designed and applied to the servo motor successfully.

V-Y and rotation flap for reconstruction of the epicanthal fold.

PubMed

Shin, Yong Ho; Hwang, Pil Joong; Hwang, Kun

2012-07-01

Epicanthoplasty is commonly performed on Asian eyelids. Consequently, overcorrection may appear. The aim of this study was to introduce a method of reconstructing the epicanthal fold and to apply this method to the patients. A V flap with an extension (eagle beak shaped) was designed on the medial canthal area. The upper incision line started near the medial end of the double-fold line, and it followed its curvature inferomedially. For the lower incision, starting at the tip (medial end) of the flap, a curvilinear incision was designed first diagonally and then horizontally along the lower blepharoplasty line. The V flap was elevated as thin as possible. Then, the upper flap was deeply undermined to make it thick. The lower flap was made a little thinner than the upper flap. Then, the upper and lower flaps were approximated to form the anteromedial surface of the epicanthal fold in a fashion sufficient to cover the red caruncle. The V flap was rotated inferolaterally over the caruncle. The tip of the V flap was sutured to the medial one-third point of the lower margin. The inferior border of the V flap and the residual lower margin were approximated. Thereafter, the posterolateral surface of the epicanthal fold was made. From 1999 to 2011, 246 patients were operated on using this method. Among them, 62 patients were followed up. The mean intercanthal distance was increased from 31.7 to 33.8 mm postoperatively. Among the 246 patients operated on, reoperation was performed for 6 patients. Among the 6 patients reoperated on, 3 cases were due to epicanthus inversus, 1 case was due to insufficient reconstruction, 1 case was due to making an infold, and 1 case was due to reopening the epicanthal fold.This V-Y and rotation flap can be a useful method for reconstruction of the epicanthal fold.

The midabdominal TRAM flap for breast reconstruction in morbidly obese patients.

PubMed

Gabbay, Joubin S; Eby, Joseph B; Kulber, David A

2005-03-01

The transverse rectus abdominis myocutaneous (TRAM) flap is ideal for postmastectomy reconstruction but is tenuous in morbidly obese patients. Because of their relatively high incidence of postoperative complications, morbidly obese patients are often not considered candidates for autogenous reconstruction. The midabdominal TRAM flap has a more favorable anatomy and may represent an alternative technique in this patient population. The records of 18 morbidly obese patients who underwent postmastectomy reconstruction using a mid-abdominal TRAM flap from 1998 through 2002 were retrospectively reviewed. The mid-abdominal TRAM flap territory includes more of the supraumbilical region than the traditional TRAM flap, corresponding to an area with more abundant musculocutaneous perforators and greater dependence on the superior epigastric vascular system. All patients underwent unipedicled mid-abdominal TRAM flap surgery. Four patients with previous subumbilical midline incisions had a delay procedure with ligation of the inferior epigastric vessels. Complications investigated were flap necrosis greater than 10 percent or sufficient to require surgical revision, abdominal donor-site breakdown, seroma formation, umbilical necrosis, abdominal wall bulging or hernia, deep vein thrombosis, infected mesh, surgical revisions, fat necrosis, and extended hospital stay. At a mean follow-up time of 15.6 months (range, 12 to 24 months), three patients had postoperative complications requiring surgical revision. Two of these patients had previous midline abdominal incisions. One patient had both partial flap necrosis and a donor-site complication. The second patient had partial flap necrosis, and the third had an abdominal donor-site complication. No occurrences of abdominal wall hernia, total flap loss, deep vein thrombosis, infected mesh, extensive surgical revision, or extended hospitalization were noted in this series. The mid-abdominal TRAM flap represents an alternative method

In situ monitoring of surgical flap viability using THz imaging (Conference Presentation)

NASA Astrophysics Data System (ADS)

Bajwa, Neha; Sung, Shijun; Grundfest, Warren; Taylor, Zachary

2016-03-01

This paper explores the utility of reflective THz imaging to assess the viability of surgical flaps. Flap surgery is a technique where tissue is harvested from a donor site and moved to a recipient while keeping the blood supply intact. This technique is common in head and neck tumor resection surgery where the reconstruction of complex and sensitive anatomic structures is routine following the resection of large and/or invasive tumors. Successful flap surgery results in tissue that is sufficiently perfused with both blood and extracellular water. If insufficient fluid levels are maintained, the flap tissue becomes necrotic and must be excised immediately to prevent infection developing and spreading to the surrounding areas. The goal of this work is to investigate the hydration of surgical flaps and correlate image features to successful graft outcomes. Advancement flaps were created on the abdomens of rat models. One rat model was labeled control and care was taken to ensure a successful flap outcome. The flap on the second rat was compromised with restricted blood flow and allowed to fail. The flaps of both rats were imaged once a day over the course of a week at which point the compromised flap had begun to show signs of necrosis. Significant differences in tissue water content were observed between rats over the experimental period. The results suggest that THz imaging may enable early assessment of flap viability.

Management of Vortices Trailing Flapped Wings via Separation Control

NASA Technical Reports Server (NTRS)

Greenblatt, David

2005-01-01

A pilot study was conducted on a flapped semi-span model to investigate the concept and viability of near-wake vortex management via separation control. Passive control was achieved by means of a simple fairing and active control was achieved via zero mass-flux blowing slots. Vortex sheet strength, estimated by integrating surface pressure ports, was used to predict vortex characteristics by means of inviscid rollup relations. Furthermore, vortices trailing the flaps were mapped using a seven-hole probe. Separation control was found to have a marked effect on vortex location, strength, tangential velocity, axial velocity and size over a wide range of angles of attack and control conditions. In general, the vortex trends were well predicted by the inviscid rollup relations. Manipulation of the separated flow near the flap edges exerted significant control over both outboard and inboard edge vortices while producing negligible lift excursions. Dynamic separation and attachment control was found to be an effective means for dynamically perturbing the vortex from arbitrarily long wavelengths down to wavelengths less than a typical wingspan. In summary, separation control has the potential for application to time-independent or time-dependent wake alleviation schemes, where the latter can be deployed to minimize adverse effects on ride-quality and dynamic structural loading.

Pharmacologic manipulation of the microcirculation in cutaneous and myocutaneous flaps in pigs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pang, C.Y.; Neligan, P.C.; Nakatsuka, T.

1985-04-01

The vascular effects of isoxsuprine, diazoxide, and isoproterenol were studied in arterial buttock flaps and latissimus dorsi myocutaneous flaps in pigs. Capillary blood flow to the skin and muscles of these flaps was measured by the radioactive microsphere (15-mu diameter) technique 6 hours postoperatively under pentobarbital anesthesia. It was observed that isoproterenol, a beta-adrenergic receptor agonist, was not effective in augmentation of skin blood flow in the arterial buttock flaps. However, isoproterenol significantly increased capillary blood flow to the arterialized portion of latissimus dorsi myocutaneous flaps compared with controls. Isoxsuprine and diazoxide (vascular smooth muscle relaxants) significantly (p less thanmore » 0.05) increased total capillary blood flow to the skin of arterial buttock flaps and to the skin and muscles of the latissimus dorsi myocutaneous flaps. However, the increase in capillary blood flow occurred mainly in the arterialized portion of these flaps. The capillary blood flow, which was supplied by the small arteries in the distal portion of the arterial buttock and latissimus dorsi flaps, was not increased by treatment with isoxsuprine or diazoxide. Therefore, there was also no increase in the maximum distance of capillary blood flow from the pedicle to the distal end of the flaps. These observations led the authors to hypothesize that different sizes (diameters) of arteries in the skin and muscle have different reactivity (or sensitivity) to vasodilatory drugs. In the present experiment, the large dominant artery of the arterial buttock and latissimus dorsi flaps responded to isoxsuprine or diazoxide (vascular smooth-muscle relaxants), resulting in an increase in blood supply to the capillaries in the proximal portion of the flaps.« less

Surgeon-Based 3D Printing for Microvascular Bone Flaps.

PubMed

Taylor, Erin M; Iorio, Matthew L

2017-07-01

Background  Three-dimensional (3D) printing has developed as a revolutionary technology with the capacity to design accurate physical models in preoperative planning. We present our experience in surgeon-based design of 3D models, using home 3D software and printing technology for use as an adjunct in vascularized bone transfer. Methods  Home 3D printing techniques were used in the design and execution of vascularized bone flap transfers to the upper extremity. Open source imaging software was used to convert preoperative computed tomography scans and create 3D models. These were printed in the surgeon's office as 3D models for the planned reconstruction. Vascularized bone flaps were designed intraoperatively based on the 3D printed models. Results  Three-dimensional models were created for intraoperative use in vascularized bone flaps, including (1) medial femoral trochlea (MFT) flap for scaphoid avascular necrosis and nonunion, (2) MFT flap for lunate avascular necrosis and nonunion, (3) medial femoral condyle (MFC) flap for wrist arthrodesis, and (4) free fibula osteocutaneous flap for distal radius septic nonunion. Templates based on the 3D models allowed for the precise and rapid contouring of well-vascularized bone flaps in situ, prior to ligating the donor pedicle. Conclusions  Surgeon-based 3D printing is a feasible, innovative technology that allows for the precise and rapid contouring of models that can be created in various configurations for pre- and intraoperative planning. The technology is easy to use, convenient, and highly economical as compared with traditional send-out manufacturing. Surgeon-based 3D printing is a useful adjunct in vascularized bone transfer. Level of Evidence  Level IV. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Vortex shedding noise of a cylinder with hairy flaps

NASA Astrophysics Data System (ADS)

Kamps, Laura; Geyer, Thomas F.; Sarradj, Ennes; Brücker, Christoph

2017-02-01

This study describes the modification of acoustic noise emitted from cylinders in a stationary subsonic flow for a cylinder equipped with flexible hairy flaps at the aft part as a passive way to manipulate the flow and acoustics. The study was motivated by the results from previous water tunnel measurements, which demonstrated that hairy flaps can modify the shedding cycle behind the cylinder and can reduce the wake deficit. In the present study, wind tunnel experiments were conducted on such a modified cylinder and the results were compared to the reference case of a plain cylinder. The acoustic spectrum was measured using two microphones while simultaneously recording the flap motion. To further examine the flow structures in the downstream vicinity of the cylinder, constant temperature anemometry measurements as well as flow visualizations were also performed. The results show that, above a certain Reynolds number, the hairy flaps lead to a jump in the vortex shedding frequency. This phenomenon is similarly observed in the water flow experiments as a jump in the non-dimensional Strouhal number that is related to the change of the shedding cycle. This jump appears to be coupled to a resonant excitation of the flaps. The specific Reynolds number at which the jump occurs is higher in the present case, which is attributed to the lower added mass in air as compared with the one in water. The flow visualizations confirmed that such action of the flaps lead to a more slender elongated shape of the time-averaged separation bubble. In addition, the hairy flaps induce a noticeable reduction of the tonal noise as well as broadband noise as long as the flaps do not touch each other.

[Modified pectoralis major myocutaneous flap in reconstruction of head and neck defects].

PubMed

Chen, Jie; Huang, Wenxiao; Li, Zan; Zhou, Xiao; Yu, Jianjun; Bao, Ronghua; Zhang, Hailin; Ling, Hang

2015-05-01

To report the experience of use of modified pectoralis major myocutaneous (PMMC) flaps in reconstruction of head and neck postoperative defects. A total of 107 patients who underwent head and neck defect reconstruction using modified PMMC flaps after tumor rescetion between Jan 2008 and Dec 2013 were analyzed retrospectively. The success rate of reconstruction with modified PMMC flaps was 94.4% (101/107). Five patients had partial flap necrosis and their wounds healed with dressing change. One patient (0.9%) had total flap necrosis, followed by the second reconstruction using contralateral PMMC flap. The modified falcate PMMC flap can obtain optimum quantity of the skin in the chest and decreasing the closing tension of the donnor site in favor of wound healing. The pedicle without muscle will not only maintain the partial function of the pectoralis major, but also help to avoid pressing the vascular pedicle within the subclavian tunnel. The muscular element the pedicled muscles of the PMMC flap can increase the ability of the flap to resist infection, which can use for covering an exposed carotid artery and improving the neck fibrosis of irradiated patients.

Unit Advancement Flap for Lower Lip Reconstruction.

PubMed

Ogino, Akihiro; Onishi, Kiyoshi; Okada, Emi; Nakamichi, Miho

2018-05-01

Lower lip reconstruction requires consideration of esthetic and functional outcome in selecting a surgical procedure, and reconstruction with local tissue is useful. The authors reconstructed full-thickness defects with a unit advancement flap. Reconstruction was performed using this method in 4 patients with lower lip squamous cell carcinoma in whom tumor resection with preservation of the mouth angle was possible. The lower lip resection width was 30 to 45 mm, accounting for 50% to 68% of the entire width of the lower lip. The flap was prepared by lateral extension from above the mental unit and matched with the potential wrinkle line of the lower lip in order to design a unit morphology surrounded by the anterior margin of the depressor labii inferioris muscle. It was elevated as a full-thickness flap composed of the orbicularis oris muscle, skin, and mucosa of the residual lower lip from the bilateral sides, and advanced to the defect. Flap transfer was adjusted by small triangular resection of the skin on the lateral side of the mental unit. The postoperative scar was inconspicuous in all patients and there was no impairment of the mouth opening-closing or articulation functions. This was a relatively simple surgical procedure. A blood supply of the flap was stable, and continuity of the orbicularis oris muscle was reconstructed by transferred the residual lower lip advancement flap from the bilateral sides. The postoperative mouth opening-closing function was sufficient, and dentures could be placed from an early phase in elderly patients. The postoperative scar was consistent with the lip unit morphology, being esthetically superior. This procedure may be applicable for reconstruction of defects approximately 1/3 to 2/3 the width of the lower lip where the mouth angle is preserved.

Pedicled unipolar latissimus dorsi flap for reconstruction of finger extensor *

PubMed Central

Takahashi, Mitsuhiko; Kasai, Tokio; Hibino, Naohito; Ishii, Seiji; Mitsuhashi, Tadashi

2017-01-01

Abstract We describe the use of a pedicled unipolar latissimus dorsi flap to restore finger extension. The patient had large defects in the radial nerve and extensor musculature. A long-tailed, 50-cm-long flap was prepared, which enabled the end of the flap to be sutured to the extensor digitorum. PMID:28470032

Three-dimensional model simulation and reconstruction of composite total maxillectomy defects with fibula osteomyocutaneous flap flow-through from radial forearm flap.

PubMed

He, Yue; Zhu, Han Guang; Zhang, Zhi Yuan; He, Jie; Sader, Robert

2009-12-01

A total maxillectomy always causes composite defects of maxilla, zygomatic bone, orbital floor or rim, and palatal and nasal mucosa lining. This leads to significant functional and cosmetic consequences after ablative surgery. The purpose of this clinical study was to preliminarily 3-dimensionally reconstruct the defect of total maxillectomy with sufficient bone support and soft tissue lining. Three-dimensional model simulation technique and free fibula osteomyocutaneous flap flow-through from radial forearm flap were used to reconstruct a total maxillectomy defect for a 21-year-old female patient. Preoperatively, the 3-dimensional (3D) simulated resin models of skeleton and fibula were used to design the osteotomies and bone segment replacement. At surgery, a 22-cm-length free fibula was divided into 4 segments to make 1 maxilla skeletal framework in the schedule of the preoperative model surgical planning with a radial forearm flap flow-through for the free fibula flap with skin paddle to repair the palatal and nasal region. Free fibula and radial forearm flap were alive, and the patient was satisfied with the results both esthetically and functionally after dental rehabilitation which was carried out 6 months after surgery. This preliminarily clinical study and case demonstrated that: the fibula osteomyocutaneous flap is an ideal donor site in 3D total maxillectomy defect reconstruction, because of its thickness, length, and bone uniformity which makes ideal support for dental rehabilitation; the flow-through forearm radial flap not only serves as the vascular bridge to midface reconstruction, but also provides sufficient soft tissue cover for the intraoral defect; and the 3D model simulation and preoperative surgical planning are effective methods to refine reconstruction surgery, shorten the surgical time, and predict the outcome after operation.

Effect of topically applied minoxidil on the survival of rat dorsal skin flap.

PubMed

Gümüş, Nazım; Odemiş, Yusuf; Yılmaz, Sarper; Tuncer, Ersin

2012-12-01

Flap necrosis still is a challenging problem in reconstructive surgery that results in irreversible tissue loss. This study evaluated the effect of topically applied minoxidil on angiogenesis and survival of a caudally based dorsal rat skin flap. For this study, 24 male Wistar rats were randomly divided into three groups of eight each. A caudally based dorsal skin flap with the dimensions of 9 × 3 cm was raised. After elevation of the flaps, they were sutured back into their initial positions. In group 1 (control group), 1 ml of isotonic saline was applied topically to the flaps of all the animals for 14 days. In group 2, minoxidil solution was spread uniformly over the flap surface for 7 days after the flap elevation. In group 3, minoxidil solution was applied topically to the flap surface during a 14-day period. On day 7 after the flap elevation, the rats were killed. The average area of flap survival was determined for each rat. Subdermal vascular architecture and angiogenesis were evaluated under a light microscope after two full-thickness skin biopsy specimens had been obtained from the midline of the flaps. The lowest flap survival rate was observed in group 1, and no difference was observed between groups 1 and 2. Compared with groups 1 and 2, group 3 had a significantly increased percentage of flap survival (P < 0.05). Intense and moderate angiogenesis also was observed respectively at the proximal and distal areas of the flaps in group 3. The results of this experiment seem to show that the early effect of minoxidil is vasodilation and that prolonged use before flap elevation leads to angiogenesis, increasing flap viability. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The Temporalis Muscle Flap for Palate Reconstruction: Case Series and Review of the Literature

PubMed Central

Brennan, Tara; Tham, Tristan M.; Costantino, Peter

2017-01-01

Introduction  The temporalis myofascial (TM) is an important reconstructive flap in palate reconstruction. Past studies have shown the temporalis myofascial flap to be safe as well as effective. Free flap reconstruction of palate defects is also a popular method used by contemporary surgeons. We aim to reaffirm the temporalis myofascial flap as a viable alternative to free flaps for palate reconstruction. Objective  We report our results using the temporalis flap for palate reconstruction in one of the largest case series reported. Our literature review is the first to describe complication rates of palate reconstruction using the TM flap. Methods  Retrospective chart review and review of the literature. Results  Fifteen patients underwent palate reconstruction with the TM flap. There were no cases of facial nerve injury. Five (33%) of these patients underwent secondary cranioplasty to address temporal hollowing after the TM flap. Three out of fifteen (20%) had flap related complications. Fourteen (93%) of the palate defects were successfully reconstructed, with the remaining case pending a secondary procedure to close the defect. Ultimately, all of the flaps (100%) survived. Conclusion  The TM flap is a viable method of palate defect closure with a high defect closure rate and flap survival rate. TM flaps are versatile in repairing palate defects of all sizes, in all regions of the palate. Cosmetic deformity created from TM flap harvest may be addressed using cranioplasty implant placement, either primarily or during a second stage procedure. PMID:28680495

Wind-Tunnel Investigation of the Effect of Angle of Attack and Flapping-Hinge Offset on Periodic Bending Moments and Flapping of a Small Rotor

NASA Technical Reports Server (NTRS)

McCarty, John Locke; Brooks, George W.; Maglieri, Domenic J.

1959-01-01

A two-blade rotor having a diameter of 4 feet and a solidity of 0.037 was tested in the Langley 300-MPH 7- by 10-foot tunnel to obtain information on the effect of certain rotor variables on the blade periodic bending moments and flapping angles during the various stages of transformation between the helicopter and autogiro configuration. Variables studied included collective pitch angle, flapping-hinge offset, rotor angle of attack, and tip-speed ratio. The results show that the blade periodic bending moments generally increase with tip-speed ratio up into the transition region, diminish over a certain range of tip-speed ratio, and increase again at higher tip-speed ratios. Above the transition region, the bending moments increase with collective pitch angle and rotor angle of attack. The absence of a flapping hinge results in a significant amplification of the periodic bending moments, the magnitudes of which increase with tip-speed ratio. When the flapping hinge is used, an increase in flapping-hinge offset results in reduced period bending moments. The aforementioned trends exhibited by the bending moments for changes in the variables are essentially duplicated by the periodic flapping motions. The existence of substantial amounts of blade stall increased both the periodic bending moments and the flapping angles. Harmonic analysis of the bending moments shows significant contributions of the higher harmonics, particularly in the transition region.

Extending the use of the gracilis muscle flap in perineal reconstruction surgery.

PubMed

Goldie, Stephen J; Almasharqah, Riyadh; Fogg, Quentin A; Anderson, William

2016-08-01

Reconstruction of the perineum is required following oncological resections. Plastic surgical techniques can be used to restore the aesthetics and function of the perineum. The gracilis myocutaneous flap provides a substantial skin paddle, with minimal donor site morbidity. The flap is pedicled on a perforator from the medial circumflex femoral artery, giving it limited reach across the perineum. Tunnelling the flap under the adductor longus muscle may free up more of the arterial pedicle, increasing its reach. On three female cadavers, bilateral gracilis flaps were raised in the standard surgical manner, giving six flaps in total. With the flaps pedicled across the perineum, the distance from the tip of each flap was measured to the anterior superior iliac spine (ASIS). The flaps were then tunnelled under the adductor longus muscle. The distances to the ASIS were measured again. The average pedicle length was greater than 7 cm. Tunnelling the flap under the adductor longus muscle increased the reach by more than 4 cm on average. Cadaveric dissection has shown that tunnelling of the flap in a novel way increase its reach across the perineum. This additional flexibility improves its use clinically and is of benefit to plastic surgeons operating in perineal reconstruction. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Acoustic characteristics of externally blown flap systems with mixer nozzles

NASA Technical Reports Server (NTRS)

Goodykoontz, J. H.; Dorsch, R. G.; Wagner, J. M.

1974-01-01

Noise tests were conducted on a large scale, cold flow model of an engine-under-the-wing externally blown flap lift augmentation system employing a mixer nozzle. The mixer nozzle was used to reduce the flap impingement velocity and, consequently, try to attenuate the additional noise caused by the interaction between the jet exhaust and the wing flap. Results from the mixer nozzle tests are summarized and compared with the results for a conical nozzle. The comparison showed that with the mixer nozzle, less noise was generated when the trailing flap was in a typical landing setting (e.g., 60 deg). However, for a takeoff flap setting (20 deg), there was little or no difference in the acoustic characteristics when either the mixer or conical nozzle was used.

Development of Bird-like Micro Aerial Vehicle with Flapping and Feathering Wing Motions

NASA Astrophysics Data System (ADS)

Maglasang, Jonathan; Goto, Norihiro; Isogai, Koji

To investigate the feasibility of a highly efficient flapping system capable of avian maneuvers, such as rapid takeoff, hover and gliding, a full scale bird-like (ornithopter) flapping-wing micro aerial vehicle (MAV) shaped and patterned after a typical pigeon (Columba livia) has been designed and constructed. Both numerical and experimental methods have been used in the development of this vehicle. This flapping-wing micro aerial vehicle utilizes both the flapping and feathering motions of an avian wing by employing a novel flapping-feathering mechanism, which has been synthesized and constructed so as to best describe the properly coordinated flapping and feathering wing motions at phase angle difference of 90° in a horizontal steady level flight condition. This design allows high flapping and feathering amplitudes and is configurable for asymmetric wing motions which are desirable in high-speed flapping flight and maneuvering. The preliminary results indicate its viability as a practical and an efficient flapping-wing micro aerial vehicle.

Indocyanine green fluorescence angiography for free flap monitoring: A pilot study.

PubMed

Hitier, Marine; Cracowski, Jean-Luc; Hamou, Cynthia; Righini, Christian; Bettega, Georges

2016-11-01

We evaluated the feasibility and the tolerance of repeated fluorescent indocyanine green angiography in free flap monitoring, and determined the intraoperative predictive values of flap vitality. The free flap failure rate has been significantly reduced, but free flap loss still occurs and remains a costly disaster. Repeated clinical examinations are commonly used for flap monitoring, but they can be unreliable because of their subjectivity. Laser-induced fluorescence of indocyanine green is a new method for assessing tissue perfusion. 20 patients undergoing microsurgical reconstruction were monitored by indocyanine green fluorescence angiography, intraoperatively, and during 4 days after surgery, with 18 injections. Monitoring was made by clinical examination, and then compared to angiographic findings. The vascular complication rate was 15% (3/20) with 2 cases of venous thrombosis and one case of partial necrosis of the flap skin paddle. Both cases of venous thrombosis were salvaged by secondary surgery. There was no total flap loss. ICG angiography allowed detecting each intra and postoperative complication, earlier than clinical examination. The mean per-operative intensity of fluorescence was significantly lower in flaps with vascular complications (23.8 GL/ms; p = 0.008). The postoperative slope (p = 0.02) and amplitude (p = 0.03) of the fluorescent signal were both significantly lower than for uncomplicated flaps, before surgical revision. These 2 parameters came back to normal values after secondary surgery. There was no adverse effect of ICG despite the repeated injections. ICG angiography is a feasible and safe technique for the detection of free flap vascular complications. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Computational Study of Porous Treatment for Altering Flap Side-Edge Flowfield

NASA Technical Reports Server (NTRS)

Choudhari, Meelan; Khorrami, Mehdi R.

2003-01-01

Reynolds-averaged Navier-Stokes calculations are used to investigate porous side-edge treatment as a passive means for flap noise reduction. Steady-state simulations are used to infer effects of the treatment on acoustically relevant features of the mean flow near the flap side edge. Application of the porous treatment over a miniscule fraction of the wetted flap area (scaling with the flap thickness) results in significantly weaker side-edge vortex structures via modification of the vortex initiation and roll-up processes. At high flap deflections, the region of axial flow reversal associated with the breakdown of the side-edge vortex is also eliminated, indicating an absence of vortex bursting in the presence of the treatment. Potential ramifications of the mean-flow modifications for flap-noise reduction are examined in the light of lessons learned from recent studies on flap noise. Computations confirm that any noise reduction benefit via the porous treatment would be achieved without compromising the aerodynamic effectiveness of the flap. Results of the parameter study contribute additional insight into the measured data from the 7x10 wind tunnel at NASA Ames and provide preliminary guidance for specifying optimal treatment characteristics in terms of treatment location, spatial extent, and flow resistance of the porous skin.

Local vascularized flaps for augmentation of Reinke's space.

PubMed

Dailey, Seth H; Gunderson, McLean; Chan, Roger; Torrealba, Jose; Kimura, Miwako; Welham, Nathan V

2011-02-01

The purpose of this study is to describe and test a novel surgical strategy for augmentation of Reinke's space using vascularized flaps: a thyroid ala perichondrium flap (TAP) and a composite thyroid ala perichondrium flap (CTAP) from the anterior larynx. We hypothesized that these specially designed vascularized flaps would remain viable once inset into the lamina propria, and that they would not disrupt rheologic, biomechanical, and histologic properties of the native vocal fold. Experimental. In vivo canine model. The length and volume of test flaps harvested in six adult human cadaveric larynges were analyzed to determine suitability for use in augmentation in the lamina propria. Also, 12 beagles randomly underwent unilateral placement of either TAP or CTAP, which were designed in accordance with the human adult cadaveric experiments. Flap perfusion was measured before and after harvest with laser Doppler. After 1 month, the beagles were humanely sacrificed and their larynges subjected to aerodynamic and acoustic evaluation using an excised larynx apparatus. The vocal fold lamina propria of four larynges--two TAP and two CTAP--underwent rheologic evaluation using a simple-shear rheometer. The remaining eight larynges underwent quantitative histologic and immunohistochemical evaluation. The survival and complication (swallowing, airway, local wound) rates of all dogs were noted. Initial studies with adult human cadaveric larynges established that TAP and CTAP possessed length and volume greater than native lamina propria. In the canine experiments, the perfusion change in the flaps was similar between flap groups. The damping ratio (ζ), dynamic viscosity (η'), elastic shear modulus (G'), and viscous shear modulus (G″) of treated and untreated native vocal folds were not statistically different. The glottic function measures of vocal efficiency, laryngeal resistance, jitter, shimmer, and harmonics-to-noise ratio (HNR) of treated and normal larynges were not

Subcutaneous pedicle propeller flap: An old technique revisited and modified!

PubMed

Karki, Durga; Mehta, Nikhil; Narayan, Ravi Prakash

2016-01-01

Post-burn axillary and elbow scar contracture is a challenging problem to the reconstructive surgeon owing to the wide range of abduction and extension that should be achieved, respectively, while treating either of the joint. The aim of this paper is to highlight the use of subcutaneous pedicle propeller flap for the management of post-burn axillary and elbow contractures. This is a prospective case study of axillary and elbow contractures managed at a tertiary care hospital using propeller flap based on subcutaneous pedicle from 2009 to 2014. Surgical treatment comprised of subcutaneous-based pedicle propeller flap from the normal tissue within the contracture based on central axis pedicle. The flap was rotated axially to break the contracture. The technique further encompassed a modification, a Zig-Zag incision of the flap, which was seen to prevent hypertrophy along the incision line. There was a mean period of 12 months of follow-up. Thirty-eight patients consisting of 22 males and 16 females were included in this study among which 23 patients had Type II axillary contractures and 15 had moderate flexion contractures at elbow joint. The post-operative abduction achieved at shoulder joint had a mean of 168° whereas extension achieved at elbow had a mean of 175°. The functional and aesthetic results were satisfactory. The choice of surgical procedure for reconstruction of post-burn upper extremity contractures should be made according to the pattern of scar contracture and the state of surrounding skin. The choice of subcutaneous pedicle propeller flap should be emphasised because of the superior functional results of flap as well as ease to learn it. Moreover, the modification of propeller flap described achieves better results in terms of scar healing. There is an inter-positioning of healthy skin in between the graft, so it prevents scar band formation all around the flap.

Angiotensin II improves random-flap viability in a rat model.

PubMed

Okuyama, N; Roda, N; Sherman, R; Guerrero, A; Dougherty, W; Nguyen, T; diZerega, G; Rodgers, K

1999-03-01

Angiotensin II (AII) is a naturally occurring peptide that has been shown to be angiogenic, cause the proliferation of several primary cell types (including endothelial cells), accelerate the repair of dermal injuries, and increase production of growth factors and extracellular matrix. The effect of a single administration of AII on the viability and vascularity of a random flap was assessed in a rat model. In the control model, the viability of the distal portion of the flap was reduced consistently by postoperative day 8. Initially, AII was administered in an aqueous vehicle (phosphate-buffered saline [PBS]) and a viscous vehicle (10% carboxymethyl cellulose [CMC]). Administration of 1 mg per milliliter AII in PBS did not affect the viability of random flaps (1.2 x 7 cm) in this animal model. However, a single administration of a higher dose of AII in PBS (10 mg per milliliter) or 1 mg per milliliter AII in the CMC vehicle resulted in 67% of the grafts being fully viable at postsurgical day 12, in contrast to vehicle-treated control flaps, none of which were fully viable at day 12. Furthermore, the portion of the flap that was viable was increased significantly (p < or = 0.05). Subsequently, a study was conducted to assess the dose-response curve for AII in a CMC vehicle in this rat model. As the dose of AII was reduced, the percentage of animals with fully viable flaps and the percentage of the flap that was viable decreased correspondingly. Administration of 0.03 mg per milliliter AII and greater increased significantly (p < or = 0.05) the viability of the flaps. In conclusion, AII appears to be highly efficacious in increasing the percentage of distal flap surface area survival when administered as a single topical dose to the wound bed.