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1

Single column locking plate fixation is inadequate in two column acetabular fractures. A biomechanical analysis  

PubMed Central

Background The objective of this study was to determine whether one can achieve stable fixation of a two column (transverse) acetabular fracture by only fixing a single column with a locking plate and unicortical locking screws. We hypothesized that a locking plate applied to the anterior column of a transverse acetabular fracture would create a construct that is more rigid than a non-locking plate, and that this construct would be biomechanically comparable to two column fixation. Methods Using urethane foam models of the pelvis, we simulated transverse acetabular fractures and stabilized them with 1) an anterior column plate with bicortical screws, 2) an anterior locking plate with unicortical screws, 3) an anterior plate and posterior column lag screw, and 4) a posterior plate with an anterior column lag screw. These constructs were mechanically loaded on a servohydraulic material testing machine. Construct stiffness and fracture displacement were measured. Result and Discussion We found that two column fixation is 54% stiffer than a single column fixation with a conventional plate with bicortical screws. There was no significant difference between fixation with an anterior column locking plate with unicortical screws and an anterior plate with posterior column lag screw. We detected a non-significant trend towards more stiffness for the anterior locking plate compared to the anterior non-locking plate. Conclusion In conclusion, a locking plate construct of the anterior column provides less stability than a traditional both column construct with posterior plate and anterior column lag screw. However, the locking construct offers greater strength than a non-locking, bicortical construct, which in addition often requires extensive contouring and its application is oftentimes accompanied by the risk of neurovascular damage.

2010-01-01

2

Plating after tibial lengthening: unilateral monoaxial external fixator and locking plate.  

PubMed

Several studies recently reported the usefulness of plating methods following limb lengthening with external fixators. This study describes modification at the time of plate insertion, selection of a locking plate, and the direction of plating. From April 2006 to July 2009, 12 consecutive patients, mean age 17.8 years, were enrolled in the study. The mean follow-up period was 36.5 months. All lengthening procedures were performed at the tibia. After proximal tibial osteotomy, a monoaxial external fixator was maintained on the lateral side of the tibia. At the end of distraction, a manually bent locking plate was inserted on the anteromedial side of the tibia, and the external fixator was removed. The mean final lengthening amount was 4.23 cm (range, 3.6-5.0 cm). The mean duration of the external fixator was 54.9 days (range, 47-67 days) and the mean external fixator index was 13.0 days/cm (range, 12.3-14.4 days/cm). The mean time to bony consolidation was 195.7 days (range, 150-264 days) and the mean healing index was 46.1 days/cm (range, 38.4-55 days). There were only minor complications in four patients. This case series showed that, especially with tibia lengthening, our method allows for successful early removal of the external fixator as compared with other methods (plating after lengthening), is associated with fewer complications, and is an effective alternative. Level of Evidence: Therapeutic Level IV. PMID:23924852

Cha, Soo-Min; Shin, Hyun-Dae; Kim, Kyung-Cheon; Song, Jae-Hwang

2013-11-01

3

The effect of fracture stability on the performance of locking plate fixation in periprosthetic femoral fractures.  

PubMed

Periprosthetic femoral fracture (PFF) fixation failures are still occurring. The effect of fracture stability and loading on PFF fixation has not been investigated and this is crucial for optimum management of PFF. Models of stable and unstable PPFs were developed and used to quantify the effect of fracture stability and loading in a single locking plate fixation. Stress on the plate was higher in the unstable compared to the stable fixation. In the case of unstable fractures, it is possible for a single locking plate fixation to provide the required mechanical environment for callus formation without significant risk of plate fracture, provided partial weight bearing is followed. In cases where partial weight bearing is unlikely, additional biological fixation could be considered. PMID:23642449

Moazen, Mehran; Mak, Jonathan H; Etchels, Lee W; Jin, Zhongmin; Wilcox, Ruth K; Jones, Alison C; Tsiridis, Eleftherios

2013-04-30

4

Biomechanical Comparison of 2 Different Locking Plate Fixation Methods in Vancouver B1 Periprosthetic Femur Fractures  

PubMed Central

Locking plates are commonly used to treat fractures around a well-fixed femoral component. The optimal construct should provide sufficient fixation while minimizing soft-tissue dissection. The purpose of the current study was to determine whether plate length, working length, or bone mineral density affects survival of locking plate fixation for Vancouver type B1 periprosthetic hip fractures. A transverse osteotomy was created just distal to cemented femoral prostheses in 9 pairs of cadaveric femurs. Fractures were stabilized with long (20-hole) or short (12-hole) locking plates that were secured proximally with cables and screws and distally with screws only. Specimens were then cycled 10 000 times at 2500 N of axial force and 15 Nm of torque to simulate full weightbearing. A motion capture system was used to record fracture displacement during cycling. Failure occurred in 5 long and 3 short plates, with no significant differences found in the number of cycles to failure. For the specimens that survived, there were no significant differences found between long and short plates for displacement or rotation observed at the fracture site. A shorter working length was not associated with increased failure rate. Lower bone mineral density was significantly associated with failure (P = .02). We concluded that long locked plates do not appear to offer a biomechanical advantage over short locking plates in terms of fixation survival, and that bone mineral density was a better predictor of failure than was the fixation construct type.

Pletka, Joshua D.; Marsland, Daniel; Belkoff, Stephen M.; Mears, Simon C.; Kates, Stephen L.

2011-01-01

5

Failure of volar locking plate fixation of an extraarticular distal radius fracture: A case report  

PubMed Central

Background Volar locking plates provide significant structural stability to the distal radius. Failure of a volar locked plating is a rarely reported complication in the literature. Case Presentation A 40 year-old, obese female patient who presented with a displaced extraarticular distal radius fracture, underwent open reduction and internal fixation of the fracture using a volar locking plate. Radiographs taken at 10 weeks postoperatively showed failure of fixation with breakage of the four distal locking screws. A hardware removal was performed at 6 months, and the patient was then lost to follow-up. She presented again at 18 months after the first surgery, with significant pain, and radiographic signs of a radial collapse and a fracture-nonunion. A total wrist fusion was performed as the method of choice at that point in time. Conclusion Volar locked plating represents the new "gold standard" of distal radius fracture fixation. However, despite the stability provided by locking plates, hardware failure may occur and lead to a cascade of complications which will ultimately require a wrist fusion, as outlined in this case report. Additional structural support by bone grafting may be needed in selected cases of volar locked plating, particularly in patients with a high risk of developing a fracture-nonunion.

2010-01-01

6

Biomechanical evaluation of fixation of comminuted olecranon fractures: one-third tubular versus locking compression plating  

Microsoft Academic Search

Introduction  New concepts in plate fixation have led to an evolution in plate design for olecranon fractures. The purpose of this study\\u000a was to compare the stiffness and strength of locking compression plate (LCP) fixation to one-third tubular plate fixation\\u000a in a cadaveric comminuted olecranon fracture model with a standardised osteotomy.\\u000a \\u000a \\u000a \\u000a \\u000a Materials and methods  Five matched pairs of cadaveric elbows were randomly

Geert A. BuijzeLeendert Blankevoort; Leendert Blankevoort; Gabriëlle J. M. Tuijthof; Inger N. Sierevelt; Peter Kloen

2010-01-01

7

Treatment of Palatal Fractures by Osteosynthesis with 2.0-mm Locking Plates as External Fixator  

PubMed Central

Treatment options for palatal fractures range from orthodontic braces, acrylic bars, and arch bars for maxillomandibular fixation to internal fixation, with plates and screws placed under the palate mucosa and periosteum, together with pyriform aperture or alveolar plating plus buttress reconstruction. Forty-five patients, ages 4 to 56, were treated using medium- or high-profile locking plates placed over the palatal mucosa as an external fixator for palatal fractures, together with treatment for other associated facial fractures. In open fractures, plates were placed after approximating the edges of the mucosal wounds. Plates and screws for palate fixation were removed at 12 weeks, when computed tomography scans provided evidence of fracture healing. All palatal fractures healed by 12 weeks, with no cases of mucosal necrosis, bone exposure, fistulae, or infections. This approach achieves adequate stability, reduces the risk of bone and mucosal necrosis, and promotes healing of mucosal wounds in case of open fractures.

Cienfuegos, Ricardo; Sierra, Eduardo; Ortiz, Benjamin; Fernandez, Gerardo

2010-01-01

8

Fixation of Traumatic Sternal Fractures Using SternaLock Plating System  

PubMed Central

A 43-year-old man experienced chest trauma due to a car accident. Compound sternal fractures with severe dislocation were seen on computed tomography of the chest. Using a SternaLock plating system with manual reduction, fixation of the sternal fracture was successfully performed. There were no complications related to the operation.

Park, Jong Bin; Lee, Han Pil; Yoo, Dong Gon; Kim, Jong Wook

2013-01-01

9

Locked plate fixation of the comminuted distal fibula: a biomechanical study  

PubMed Central

Background The purpose of this study was to compare the biomechanical properties of locked versus nonlocked lateral fibular bridge plating of comminuted, unstable ankle fractures in a mode of catastrophic failure. Methods We created comminuted Weber C fractures in 8 paired limbs from fresh cadavers. Fractures were plated with either standard or locked one-third tubular bridge plating techniques. Specimens were biomechanically evaluated by external rotation to failure while subjected to a compressive load approximating body weight. We measured the angle to failure, torque to failure, energy to failure and construct stiffness. Results There was no significant difference in construct stiffness or other biomechanical properties between locked and standard one-third tubular plating techniques. Conclusion We found no difference in biomechanical properties between locked and standard bridge plating of a comminuted Weber C fibular fracture in a model of catastrophic failure. It is likely that augmentation of fixation with K-wires or trans-tibial screws provides a construct superior to locked bridge plating alone. Further biomechanical and clinical analysis is required to improve understanding of the role of locked plating in ankle fractures and in osteoporotic bone.

White, Neil J.; Corr, David T.; Wagg, James P.; Lorincz, Caeley; Buckley, Richard E.

2013-01-01

10

Load Sharing Mechanism Across Graft-Bone Interface in Static Cervical Locking Plate Fixation  

PubMed Central

Objective This study is a retrospective clinical study over more than 4 years of follow up to understand the mechanism of load sharing across the graft-bone interface in the static locking plate (SLP) fixation compared with non-locking plate (NLP). Methods Orion locking plates and Top non-locking plates were used for SLP fixation in 29 patients and NLP fixation in 24 patients, respectively. Successful interbody fusion was estimated by dynamic X-ray films. The checking parameters were as follows : screw angle (SA) between upper and lower screw, anterior and posterior height of fusion segment between upper and lower endplate (AH & PH), and upper and lower distance from vertebral endplate to the end of plate (UD & LD). Each follow-up value of AH and PH were compared to initial values. Contributions of upper and lower collapse to whole segment collapse were estimated. Results Successful intervertebral bone fusion rate was 100% in the SLP group and 92% in the NLP group. The follow-up mean value of SA in SLP group was not significantly changed compared with initial value, but follow-up mean value of SA in NLP group decreased more than those in SLP group (p=0.0067). Statistical analysis did not show a significant difference in the change in AH and PH between SLP and NLP groups (p>0.05). Follow-up AH of NLP group showed more collapse than PH of same group (p=0.04). The upper portion of the vertebral body collapsed more than the lower portion in the SLP fixation (p=0.00058). Conclusion The fused segments with SLP had successful bone fusion without change in initial screw angle, which was not observed in NLP fixation. It suggests that there was enough load sharing across bone-graft interface in SLP fixation.

Han, In Ho; Kuh, Sung Uk; Chin, Dong Kyu; Jin, Byung Ho; Cho, Yong Eun

2009-01-01

11

Residual wrist pain after volar locking plate fixation of distal radius fractures.  

PubMed

A prospective multicenter clinical study evaluated, using the Hand20 and hand diagram, the disability, incidence, location, and predictive factors of residual wrist pain 18 months after volar locking plate fixation of distal radius fracture in 122 patients. The average Hand20 score and numeric rating scores for pain were 13.1 +/- 18.2 and 2.1 +/- 23, respectively. Fifty-seven patients indicated that they had pain. Among those patients, 25 had ulnar pain and 45 had radial pain. The incidence of radial-sided wrist pain was higher than ulnar-sided wrist pain. Logistic regression analysis showed that female sex and intra-articular fracture significantly correlated with radial-sided wrist pain. Volar locking plate fixation maintained anatomical reduction; however, a significant number of patients complained of residual wrist pain. PMID:23162956

Kurimoto, Shigeru; Tatebe, Masahiro; Shinohara, Takaaki; Arai, Tetsuya; Hirata, Hitoshi

2012-10-01

12

Using a Reconstruction Locking Compression Plate as External Fixator in Infected Open Clavicle Fracture  

PubMed Central

Open clavicle fracture is an uncommon injury mostly caused by severe direct trauma. It is often associated with multiple organ injuries. Generally, surgical intervention with debridement and fracture repair is always indicated in order to prevent infection, non-union, and malalignment. In situations of bony exposure and significant contamination concomitant with severe soft tissue damage, the external fixation is the treatment of choice because of the possibility it offers of providing stable fixation with minimal local tissue damage resulting in excellent union rates and better soft tissue outcome. Nevertheless, traditional external fixation encountered some potential problems as its bulkiness and sharp edges caused discomfort to the patient. In this study, we present an interesting case of a polytraumatized patient with a gunshot injury with complex open clavicle fracture that was successfully treated with external fixation using reconstruction with a locking compression plate as definitive treatment.

Sirisreetreerux, Norachart; Sa-ngasoongsong, Paphon; Chanplakorn, Pongsthorn; Kulachote, Noratep; Laohajaroensombat, Sukij; Suphachatwong, Chanyut; Phiphobmongkol, Vajara; Wajanavisit, Wiwat

2013-01-01

13

Using a reconstruction locking compression plate as external fixator in infected open clavicle fracture.  

PubMed

Open clavicle fracture is an uncommon injury mostly caused by severe direct trauma. It is often associated with multiple organ injuries. Generally, surgical intervention with debridement and fracture repair is always indicated in order to prevent infection, non-union, and malalignment. In situations of bony exposure and significant contamination concomitant with severe soft tissue damage, the external fixation is the treatment of choice because of the possibility it offers of providing stable fixation with minimal local tissue damage resulting in excellent union rates and better soft tissue outcome. Nevertheless, traditional external fixation encountered some potential problems as its bulkiness and sharp edges caused discomfort to the patient. In this study, we present an interesting case of a polytraumatized patient with a gunshot injury with complex open clavicle fracture that was successfully treated with external fixation using reconstruction with a locking compression plate as definitive treatment. PMID:23888201

Sirisreetreerux, Norachart; Sa-Ngasoongsong, Paphon; Chanplakorn, Pongsthorn; Kulachote, Noratep; Laohajaroensombat, Sukij; Suphachatwong, Chanyut; Phiphobmongkol, Vajara; Wajanavisit, Wiwat

2013-06-07

14

Fixation of the Lapidus arthrodesis with a plantar interfragmentary screw and medial low profile locking plate.  

PubMed

The Lapidus arthrodesis can be used to correct pathology within the forefoot or midfoot, and severe hallux valgus deformities as well as hypermobility of the medial column may be amenable to correction with this procedure. Many different skeletal fixation methods have been described for this procedure, and one form that appears to provide enough construct stability to allow patients to bear weight early in the postoperative period is described herein. This construct consists of an interfragmental compression screw oriented from the plantar aspect of the first metatarsal to the superior aspect of the medial cuneiform, with medial locking plate augmentation. PMID:22632842

Cottom, James M

2012-05-24

15

Risk Factors for Failure of Locked Plate Fixation of Distal Femur Fractures: An Analysis of 335 Cases.  

PubMed

OBJECTIVES:: Locked plating has become a standard method to treat supracondylar femur fractures. Emerging evidence indicates this method of treatment is associated with modest failure rates. The goals of this study were to determine risk factors for complications and to provide technical recommendations for locked plating of supracondylar femur fractures. DESIGN:: Retrospective review SETTING:: Three Level I or II Trauma Centers PATIENTS/PARTICIPANTS:: Three-hundred twenty-six patients with 335 distal femur fractures (OTA 33A or C, 33% open) treated with lateral locked plates were studied. The average patient age was 57 years (range 17 - 97 years), 55% were female, 34% obese, 19% diabetic, and 24% smokers. INTERVENTION:: All patients were managed with open reduction internal fixation (ORIF) using a lateral distal femoral locked plate construct that included locked screws in the distal fragment and either non-locked, locked or a combination of locked and non-locked screws in the proximal fragment. MAIN OUTCOME MEASUREMENTS:: Risk factors for re-operation to promote union, deep infection, and implant failure. RESULTS:: After the index procedure, 64 fractures (19%) required re-operation to promote union, including 30 that had a planned staged bone grafting due to metaphyseal defect after debridement of an open fracture. Independent risk factors for re-operation to promote union and deep infection included diabetes and open fracture. Risk factors for proximal implant failure included open fracture, smoking, increased body mass index, and shorter plate length. CONCLUSIONS:: The identified risk factors for re-operation to promote union and complications included open fracture, diabetes, smoking, increased body mass index, and shorter plate length. The majority of these factors are out of surgeon control, but are useful when considering prognosis. Use of relatively long plates is a technical factor that can reduce risk for fixation failure. PMID:23760176

Ricci, William M; Streubel, Philipp N; Morshed, Saam; Collinge, Cory; Nork, Sean E; Gardner, Michael J

2013-06-11

16

Bone transport combined with locking bridge plate fixation for the treatment of tibial segmental defects: a report of 2 cases.  

PubMed

Segmental tibial bone loss, specifically in the setting of high-energy trauma, presents a challenging problem to the treating orthopaedic surgeon. These injuries are often complicated by tissue loss, poor wound healing, and infection. Many techniques of reconstruction have been advocated from bone grafting to bone transport. Transport can accomplished using Ilizarov frames, monolateral external fixators, and intramedullary devices. Although transport over an intramedullary device offers the advantage of rigidity and controlled alignment, many authors consider prolonged external fixation and history of pin tract infection to be contraindications to this technique. To our knowledge, bone segment transport used in combination with locking plate fixation has not been described for the treatment of tibial bone defects. We describe two cases of bone transport using a combination of locked plate fixation and a monolateral external fixation frame for large tibial bone defects. This technique allows for easy correction of length and alignment, stable fixation, facilitates quicker, and easier frame removal and also allows for compression of transported segment at the time of docking. PMID:22955338

Girard, Paul J; Kuhn, Kevin M; Bailey, James R; Lynott, John A; Mazurek, Michael T

2013-09-01

17

Radiation-Associated Fracture Nonunion of the Clavicle Treated with Locking Plate Fixation and Autologous Bone Grafting  

PubMed Central

We describe a case of radiation-associated fracture nonunion of the clavicle, which was treated by locking plate fixation and autologous bone grafting. The patient was a 67-year old man who received 70?Gy radiation therapy to treat nasopharyngeal carcinoma. Eight years later, he suffered a pathological fracture of the right clavicle. One year after the fracture, surgical treatment was performed due to persistent pain and weakness. Radiographs demonstrated atrophic nonunion. Bone scan demonstrated hot uptake at both ends of the fractured bone. MRI demonstrated a formation of pseudoarthrosis with fluid collection and suggested bone marrow edema at both ends of the fracture fragments. In surgery, fibrous pseudoarthrosis tissue was excised and both ends of the fracture fragments were refreshed to identify bleeding. Open reduction and internal fixation using a 7-hole locking plate and autologous bone grafting were performed. Successful bony union was obtained 1 year postoperatively, and no adverse events were observed up to 52 months after the operation. Our case suggests that a locking plate provides sufficient fixation and autologous bone grafting is effective in enhancing bone healing in a radiation-associated fracture nonunion of the clavicle in which it is difficult to achieve bony union.

Lee, Sang Yang; Nishida, Kotaro; Kuroda, Ryosuke; Kurosaka, Masahiro

2012-01-01

18

Locking plate fixation of proximal humeral fractures with impaction of the fracture site to restore medial column support: a biomechanical study.  

PubMed

BACKGROUND: Despite the advent of locking plate techniques, proximal humeral fracture fixation can fail due to varus collapse, especially in osteoporotic bone with medial cortex comminution. This study investigated the effect of restoring the integrity of the medial column by fracture impaction and shaft medialization with locking plate fixation. This construct was compared with a traditional locking plate construct under conditions of varus cyclical loading. MATERIALS AND METHODS: Proximal humeral fractures with medial comminution were simulated by performing wedge-shaped osteotomies at the surgical neck in cadaveric specimens and removing 1 cm of medial cortex. For each cadaver (n = 6), 1 humeral fracture was fixed with a traditional locking plate construct. The other was fixed with the locking plate construct plus fracture impaction and shaft medialization, resulting in medial column restoration. The humeral head was immobilized, and a repetitive, varus force was applied to the humeral shaft until construct collapse or until 25,000 cycles were completed. RESULTS: None of the constructs with fracture impaction collapsed, whereas 5 of 6 of the nonaugmented constructs collapsed before reaching 25,000 cycles (P = .008). Collapse of the 5 nonimpacted constructs that failed occurred after an average of 11,470 ± 3589 cycles. CONCLUSION: Fracture impaction increased the ability of the locking plate to withstand repetitive varus loading. This technique provides a construct biomechanically superior to locking plate fixation alone. PMID:23639833

Weeks, Colleen A; Begum, Farhana; Beaupre, Lauren A; Carey, Jason P; Adeeb, Samer; Bouliane, Martin J

2013-04-29

19

The Search for the Ideal Fixation of Palatal Fractures: Innovative Experience with a Mini-Locking Plate  

PubMed Central

Fractures of the palate have defied conventional management, such that malrotation and disinclination of the palatal shelves occur in a significant number of patients after repair. The fractured palatal shelves of eight patients were first prealigned. To do so, one or more 205-mm ratchet clamps and two intermaxillary fixation (IMF) posts were used. Rigid fixation was then achieved by applying a 2.0-mm mini-locking titanium plate (across the palatal vault) and by applying an adaptation miniplate across the fracture line as it exited the anterior surface of the maxilla. Screws were passed directly through the mucoperiosteum, to engage the palatal shelves and to lock the locking plate into position. Lacerations in the mucoperiosteum were neither used to aid fixation nor used as portals for dissection; incisions and mucoperiosteal flaps in the palatal vault were avoided. Adjuncts, such as intraoral splints, have not been used in cases to date, and early mobilization was allowed. Reconstitution of the craniomaxillofacial buttresses was added in patients with more extensive maxillary injury. The palatal appliance and screws remained rigidly in position in the roof of the mouth, much like an external fixator, until their removal 8 to 12 weeks after the repair. No patient suffered erosion of the mucoperiosteum or other major morbidity, other than a transient fistula of the soft palate. The palatoalveolar segments remained in proper realignment and inclination, and pretraumatic occlusal patterns and the width and depth of the lower face appear to have been restored with one exception. The latter suffered a subtle posterolateral open bite that was corrected orthodontically. Prealignment of fractured palatal shelves with one or more large ratchet clamps and two IMF posts provides several points of forced reduction of the palatal shelves, along the dental arch. In addition, stabilization with mini-locking plate(s) in the palatal vault and an adaptation plate across the fracture line, as it exits the maxilla, appear to have merit, based on this preliminary report (n?=?8). Outcomes seen on computed tomography and clinical examination during this 3-year experience have been favorable.

Pollock, Richard A.

2008-01-01

20

Early Weight Bearing of Calcaneal Fractures Treated by Intraoperative 3D-Fluoroscopy and Locked-Screw Plate Fixation  

PubMed Central

Operative therapy of intraarticular fractures of the calcaneus is an established surgical standard. The aim is an accurate reduction of the fracture with reconstruction of Boehler’s angle, length, axis and subtalar joint surface. Intraoperative 3D-fluoroscopy with the Siremobil Iso-C 3D® mobile C-arm system is a valuable assistant for accurate reconstruction of these anatomical structures. Remaining incongruities can be recognized and corrected intraoperatively. The achieved reduction can be fixed by the advantages of an internal fixator (locked-screw plate interface). In the period of October 2002 until April 2007 we operated 136 patients with intraarticular fractures of the calcaneus by means of anatomical reduction, and internal plate fixator under intraoperative control of 3D-fluoroscopy. All patients were supplied with an orthesis after the operation which allowed weight bearing of 10 kg for 12 weeks for the patients operated between October 2002 and October 2004 (Group A). Transient local osteoporosis was observed in all X-Rays at follow-up after an average of 8,6 months. Therefore we changed our postoperative treatment plan for the patients operated between November 2004 and April 2007 (Group B). Weight bearing started with 20 KG after 6 weeks, was increased to 40 KG after 8 weeks and full weight bearing was allowed after 10 weeks for these patients. In no case a secondary dislocation of the fracture was seen. No bone graft was used. At follow up the average American Foot and Ankle Society Score (AOFAS) were 81 for Group_A, compared to 84 for Group B, treated with earlier weight bearing. Autologous bone graft was not necessary even if weight bearing was started after a period of six weeks postoperatively. The combination of 3D-fluoroscopy with locked internal fixation showed promising results. If the rate of patients developing subtalar arthrosis will decrease by this management will have to be shown in long term follow up.

Kienast, B; Gille, J; Queitsch, C; Kaiser, M.M; Thietje, R; Juergens, C; Schulz, A.P

2009-01-01

21

Sternal fixation with nonspecific plate.  

PubMed

Purpose: The aim of the present study was to fixate displaced sternum fractures with a nonspecific plate, without a sternotomy procedure.Method: Between May 2010 and December 2011, 15 patients with sternal fractures were included in this study. We performed fixation for 8 of 15 sternal fracture patients.Posteroanterior and lateral chest x-rays and computed tomography were taken for diagnosis of sternal fractures. Our surgical indications were severe pain, dislocationoverlapping of sternal edges, and thoracic wall instability. Locked volar distal radius plates were used for the sternal fixation.Results: After fixation of sternum with plate, the sternum was stable in all 8 patients.There were no complications intra- or postoperatively. Sternal union was observed for all. Pain relief was determined dramatically.Conclusion: Locked volar distal radius plates can be used for displaced sternal fractures.It is an alternative and successful method for sternal fractures. PMID:23269267

Ergene, Gökhan; Tulay, Cumhur Murat; Anas?z, Hüseyin

2012-12-26

22

Fixation of lapidus arthrodesis with a plantar interfragmentary screw and medial locking plate: a report of 88 cases.  

PubMed

Lapidus arthrodesis is a powerful procedure that can be used to correct pathologic features within the forefoot or midfoot. Many different methods of fixation for this procedure have been reported. The use of plating constructs has been shown to provide increased stability compared with screw-only constructs. The technique we have described consists of a plantar to dorsal retrograde lag screw across the arthrodesis site, coupled with a low-profile medial locking plate. A total of 88 consecutive patients were treated with this modification of the Lapidus procedure by 2 surgeons and were retrospectively evaluated. All patients followed an early postoperative weightbearing protocol. Patient age, gender, follow-up duration, interval to weightbearing and radiographic fusion, preoperative and postoperative intermetatarsal angle, hardware removal, preoperative and postoperative American Orthopaedic Foot and Ankle Society midfoot scores, and adjunct procedures were analyzed. The mean follow-up period was 16.76 ± 5.9 (range 12 to 36) months, and all healed fusions demonstrated radiographic union at a mean of 51 ± 19.1 (range 40 to 89) days. The patients were treated with weightbearing starting a mean of 10.90 ± 4.1 (range 5 to 28) days postoperatively. Complications included 15 patients (17%) requiring hardware removal, 2 cases (2%) of hallux varus, 6 cases (7%) of radiographic recurrent hallux valgus, and 2 patients (2%) with first metatarsocuneiform nonunion. The results of the present study have demonstrated that plantar lag screw fixation with medial locking plate augmentation for Lapidus arthrodesis allows for early weightbearing with satisfactory outcomes, improved clinical and radiographic alignment, and improved American Orthopaedic Foot and Ankle Society scores. PMID:23540755

Cottom, James M; Vora, Anand M

2013-03-27

23

Metaphyseal locking plate as a definitive external fixator for treating open tibial fractures--clinical outcome and a finite element study.  

PubMed

We evaluated both the outcome of using a locking plate as a definitive external fixator for treating open tibial fractures and, using finite element analysis, the biomechanical performance of external and internal metaphyseal locked plates in treating proximal tibial fractures. Eight open tibial patients were treated using a metaphyseal locked plate as a low-profile definitive external fixator. Then, finite element models of internal (IPF) as well as two different external plate fixations (EPFs) for proximal tibial fractures were reconstructed. The offset distances from the bone surface to the EPFs were 6 cm and 10 cm. Both axial stiffness and angular stiffness were calculated to evaluate the biomechanical performance of these three models. The mean follow-up period was 31 months (range, 18-43 months). All the fractures united and the mean bone healing time was 37.5 weeks (range, 20-52 weeks). All patients had excellent or good functional results and were walking freely at the final follow-up. The finite element finding revealed that axial stiffness and angular stiffness decreased as the offset distance from the bone surface increased. Compared to the IPF models, in the two EPF models, axial stiffness decreased by 84-94%, whereas the angular stiffness decreased by 12-21%. The locking plate used as a definitive external fixator provided a high rate of union. While the locking plate is not totally rigid, it is clinically stable and may be advisable for stiffness reduction of plating constructs, thus promoting fracture healing by callus formation. Our patients experienced a comfortable clinical course, excellent knee and ankle joint motion, satisfactory functional results and an acceptable complication rate. PMID:23706173

Ma, Ching-Hou; Wu, Chin-Hsien; Tu, Yuan-Kun; Lin, Ting-Sheng

2013-05-22

24

[Mono- versus polyaxial locking plates].  

PubMed

Conventional plate osteosynthesis is undergoing a period of transition. The concept of locking plate osteosynthesis is of special importance. Monoaxial locking plate osteosynthesis has shown promising results (rapid bone healing via callus, minimal soft tissue irritation, advantageous in osteoporosis). Some implants allow for polyaxial locking. The first results of comparative studies concerning biomechanics and clinical outcome of mono- versus polyaxial locking plates are presented. PMID:23934534

Hanschen, M; Biberthaler, P

2013-08-01

25

Fixation of subtrochanteric extending\\/derotational femoral osteotomies with the Locking Compression Plate in ambulatory neuro-orthopaedic patients  

Microsoft Academic Search

Purpose  Patients with neuro-orthopaedic disorders often develop hip flexion contractures or rotational hip deformities. Increasing\\u000a deformities impair the already diminished walking abilities and proximal femoral osteotomies are often performed to maintain\\/improve\\u000a walking abilities. Fixation of the osteotomies with condylar plates has been successfully used but does often not allow immediate\\u000a postoperative full weight bearing. To avoid a substantial postoperative rehabilitation deficit

Mathias Haefeli; Hanspeter Huber; Stefan Dierauer; Leonhard E. Ramseier

2010-01-01

26

Locking buttons increase fatigue life of locking plates in a segmental bone defect model.  

PubMed

BACKGROUND : Durability of plate fixation is important in delayed union. Although locking plates result in stronger constructs, it is not known if locking affects the fatigue life of a plate. Two locking screws on either side of the nonunion could decrease working length and increase strain in the plate. However, the reinforcing effect of the locking head on the plate may compensate, so that it is unclear whether locking reduces fatigue life. QUESTIONS/PURPOSES : We determined whether locking screws, compression screws, and locking buttons reduce or increase the fatigue life of a plate. METHODS : We tested fatigue life of four constructs using an eight-hole locking plate in a segmental defect model: (1) all locking screws (Locked; n = 5); (2) all compression screws (Unlocked; n = 5); (3) six compression screws with two locking buttons in the central holes (Button; n = 6); and (4) six compression screws with two open central holes (Open; n = 6). RESULTS : The Button group had the longest fatigue life (1.3 million cycles). There was no difference between the Locked and Unlocked groups. All of the constructs failed by fracture of the plates through a screw hole adjacent to the defect. CONCLUSIONS : Locking screws did not improve fatigue life, however a locking button increased the fatigue life of a locking plate in a segmental bone defect model. CLINICAL RELEVANCE : Locking buttons in holes adjacent to a defect may improve durability, which is important when delayed union is a possibility. PMID:23104045

Tompkins, Marc; Paller, David J; Moore, Douglas C; Crisco, Joseph J; Terek, Richard M

2012-10-27

27

Internal fixation of intracapsular fractures of the hip using a dynamic locking plate: Two-year follow-up of 320 patients.  

PubMed

A consecutive series of 320 patients with an intracapsular fracture of the hip treated with a dynamic locking plate (Targon Femoral Neck (TFN)) were reviewed. All surviving patients were followed for a minimum of two years. During the follow-up period 109 patients died. There were 112 undisplaced fractures, of which three (2.7%) developed nonunion or re-displacement and five (4.5%) developed avascular necrosis of the femoral head. Revision to an arthroplasty was required for five patients (4.5%). A further six patients (5.4%) had elective removal of the plate and screws. There were 208 displaced fractures, of which 32 (15.4%) developed nonunion or re-displacement and 23 (11.1%) developed avascular necrosis. A further four patients (1.9%) developed a secondary fracture around the TFN. Revision to a hip replacement was required for 43 patients (20.7%) patients and a further seven (3.3%) had elective removal of the plate and screws. It is suggested that the stronger distal fixation combined with rotational stability may lead to a reduced incidence of complications related to the healing of the fracture when compared with other contemporary fixation devices but this needs to be confirmed in further studies. Cite this article: Bone Joint J 2013;95-B:1402-5. PMID:24078540

Parker, M; Cawley, S; Palial, V

2013-10-01

28

Internal fixation of a traumatic fracture around a hip resurfacing arthroplasty using the proximal femoral locking compression plate.  

PubMed

We report on a 40-year-old man who sustained a traumatic extracapsular fracture of the proximal femur with a Birmingham Hip Resurfacing in situ. It was decided to retain the resurfacing implant and a proximal femoral periarticular locking compression plate (Synthes) was used to stabilise the fracture. The patient regained full range of pain-free movement, and was bearing his full weight on the operated leg by 18 weeks. He had a Harris Hip score of 90. Fractures around hip resurfacing arthroplasties are an emerging problem, and a literature review reveals two distinct modes of presentation i.e. 'atraumatic' and 'traumatic' fractures. We elaborate on these two different fracture patterns, with emphasis on the epidemiology, biomechanical considerations, and management strategies for the 'traumatic' type of periprosthetic fracture. PMID:23162970

Weusten, Axel J; Khan, Sameer K; Bonczek, Sandra J; Elsharief, Deena; Wallace, Ian W

2012-10-01

29

Finite element comparison of retrograde intramedullary nailing and locking plate fixation with/without an intramedullary allograft for distal femur fracture following total knee arthroplasty.  

PubMed

PURPOSE: Periprosthetic distal femur fracture after total knee arthroplasty due to the stress-shielding phenomenon is a challenging problem. Retrograde intramedullary nail (RIMN) or locking plate (LP) fixation with/without a strut allograft has been clinically used via less invasive stabilization surgery (LISS) for the treatment of these periprosthetic fractures. However, their biomechanical differences in construct stability and implant stress have not been extensively studied, especially for the osteoporotic femur. METHODS: This study used a finite-element method to evaluate the differences between RIMN, LP, and LP/allograft fixation in treating periprosthetic distal femur fractures. There were sixteen variations of two fracture angles (transverse and oblique), two loading conditions (compression and rotation), and four bony conditions (one normal and three osteoporotic). Construct stiffness, fracture micromotion, and implant stress were chosen as the comparison indices. RESULTS: The LP/allograft construct provides both lateral and middle supports to the displaced femur. Comparatively, the LP and RIMN constructs, respectively, transmit the loads through the lateral and middle paths, thus providing more unstable support to the construct and high stressing on the implants. The fracture pattern plays a minor role in the construct stabilization of the three implants. In general, the biomechanical performances of the RIMN and LP constructs were comparable and significantly inferior to those of the LP/allograft construct. The bone quality should be evaluated prior to the selection of internal fixators. CONCLUSIONS: The LP/allograft construct significantly stabilizes the fracture gap, reduces the implant stress, and serves as the recommended fixation for periprosthetic distal femur fracture. PMID:23582376

Chen, Shih-Hao; Chiang, Ming-Chieh; Hung, Ching-Hua; Lin, Shang-Chih; Chang, Hsiao-Wei

2013-04-10

30

Mechanical evaluation of fourth-generation composite femur hybrid locking plate constructs  

Microsoft Academic Search

Locking compression plates are routinely used for open reduction and internal fixation of fractures. Such plates allow for\\u000a locking or non-locking screw placement in each hole. A combined use of both types of screw application for stabilization of\\u000a a fracture is commonly applied and referred to as hybrid internal fixation. Locking screws improve the stability of the fixation\\u000a construct but

Tarun Goswami; Vinit Patel; David J. Dalstrom; Michael J. Prayson

31

Locking plate construct for femoral shaft fractures in skeletally immature patients  

Microsoft Academic Search

Different methods of internal fixation are used in the treatment of femoral shaft fractures. Results of locked plate fixation in adults have been encouraging. A locking plate construct with a standard broad Dynamic Compression Plate (DCP) and 4.5 mm nuts was used in the treatment of femoral shaft fractures in 15 skeletally immature patients. There were 12 boys and three

Akram H AMMAD

32

[Overseas advance on the use of locking plates].  

PubMed

Locking plate technology offers improved fixation stability in osteopenic bone and for comminuted and periarticular fractures. The additional stability per screw compared with that of conventional nonlocking fixation enhances the application of minimally invasive fracture techniques. The application of locking plates is somewhat more difficult than the placement of conventional plates. Fracture reductions are often done indirectly, the locking screw must be carefully aligned along the axis of the receiving hole to ensure proper tightness, and the length of the plate must be selected carefully. The use of locking plates will likely increase, particularly with the increasing prevalence of osteopenic fractures on our aging population and the increase in high-energy fractures in younger patients severe trauma. PMID:19753999

Zhang, Gong-lin; Ge, Bao-feng

2009-08-01

33

Far Cortical Locking Can Reduce Stiffness of Locked Plating Constructs While Retaining Construct Strength  

PubMed Central

Background: Several strategies to reduce construct stiffness have been proposed to promote secondary bone healing following fracture fixation with locked bridge plating constructs. However, stiffness reduction is typically gained at the cost of construct strength. In the present study, we tested whether a novel strategy for stiffness reduction, termed far cortical locking, can significantly reduce the stiffness of a locked plating construct while retaining its strength. Methods: Locked plating constructs and far cortical locking constructs were tested in a diaphyseal bridge plating model of the non-osteoporotic femoral diaphysis to determine construct stiffness in axial compression, torsion, and bending. Subsequently, constructs were dynamically loaded until failure in each loading mode to determine construct strength and failure modes. Finally, failure tests were repeated in a validated model of the osteoporotic femoral diaphysis to determine construct strength and failure modes in a worst-case scenario of bridge plating in osteoporotic bone. Results: Compared with the locked plating constructs, the initial stiffness of far cortical locking constructs was 88% lower in axial compression (p < 0.001), 58% lower in torsion (p < 0.001), and 29% lower in bending (p < 0.001). Compared with the locked plating constructs, the strength of far cortical locking constructs was 7% lower (p = 0.005) and 16% lower (p < 0.001) under axial compression in the non-osteoporotic and osteoporotic diaphysis, respectively. However, far cortical locking constructs were 54% stronger (p < 0.001) and 9% stronger (p = 0.04) under torsion and 21% stronger (p < 0.001) and 20% stronger (p = 0.02) under bending than locked plating constructs in the non-osteoporotic and osteoporotic diaphysis, respectively. Within the initial stiffness range, far cortical locking constructs generated nearly parallel interfragmentary motion. Locked plating constructs generated significantly less motion at the near cortex adjacent to the plate than at the far cortex (p < 0.01). Conclusions: Far cortical locking significantly reduces the axial stiffness of a locked plating construct. This gain in flexibility causes only a modest reduction in axial strength and increased torsional and bending strength. Clinical Relevance: Far cortical locking may provide a novel bridge plating strategy to enhance interfragmentary motion for the promotion of secondary bone healing while retaining sufficient construct strength.

Bottlang, Michael; Doornink, Josef; Fitzpatrick, Daniel C.; Madey, Steven M.

2009-01-01

34

Tibiotalocalcaneal arthrodesis using a femoral locking plate.  

PubMed

The goal of a tibiotalocalcaneal arthrodesis is to create a pain-free, stable hindfoot and ankle. Although a reserved procedure, it is useful when simultaneous ankle and subtalar joint pathology exists. Numerous complications have been reported after tibiotalocalcaneal arthrodesis, most importantly nonunion. Locking plates have proved to be a more stable construct than alternative forms of arthrodesis. In the inverted positions, the hybrid plating of the femoral locking plate structurally aligns with the anatomy of the hindfoot. This provides an anatomically sound construct, while allowing for both locking and lag screw insertion. We describe a new technique using a 4.5-mm condylar plate for tibiotalocalcaneal arthrodesis. PMID:21945399

DiDomenico, Lawrence A; Wargo-Dorsey, Mari

2011-09-25

35

Biomechanical comparison of a locking plate with intraplate compression screw versus locking plate with plantar interfragmentary screw for Lapidus arthrodesis: a cadaveric study.  

PubMed

Lapidus arthrodesis (first metatarsal cuneiform arthrodesis) has become an accepted procedure for hallux abducto valgus. Several variations of fixation have been described. Earlier weightbearing postoperatively has been one reported benefit of using locking plates for fixation. Additionally, studies have demonstrated that fixation placed on the plantar or tension side of the arthrodesis increases the biomechanical advantage. We performed a biomechanical cadaveric study of the Lapidus procedure, comparing a previously reported technique using a low profile locking plate with an intraplate compression screw versus the same locking plate with a plantar interfragmentary screw (PIFS) placed on the tension side of the arthrodesis in 10 fresh, paired, cadaver limbs. The mean ultimate load of the plate with a PIFS was 383.2 ± 211.5 N, and the mean ultimate load of the plate with an intraplate compression screw was 205.5 ± 97.2 N. The mean ultimate load of the LPS Lapidus plate with a PIFS was statistically greater (p = .027) than that with the plate intraplate compression screw. Our results indicated that changing the orientation of the compression screw to a PIFS significantly increased the stability of the Lapidus arthrodesis fixation construct. The modified construct with the PIFS might decrease the incidence of nonunion and, ultimately, allow patients to bear weight faster postoperatively. PMID:23621977

Cottom, James M; Rigby, Ryan B

36

Use of SternaLock plating system in acute treatment of unstable traumatic sternal fractures.  

PubMed

Optimal surgical treatment of unstable sternal fractures is controversial. Wiring provides suboptimal fixation and adaptations of existing non-sternum specific plating systems may be dangerous when rapid sternal reentry is required. We present our experience with the sternal specific fixation system, SternaLock (Biomet Microfixation Inc, Jacksonville, FL), in the acute treatment of transverse sternal body fractures in 2 patients who sustained significant blunt anterior chest wall trauma. SternaLock provides the rigid sternal fixation necessary for reliable fracture healing while offering advantages over other systems with regards to ease of use and safety. PMID:21256325

Chou, Stephanie S; Sena, Matthew J; Wong, Michael S

2011-02-01

37

Extensor indicis proprius and extensor digitorum communis rupture after volar locked plating of the distal radius--a case report.  

PubMed

Distal radius fractures are among the most commonly encountered fractures in the extremities. Volar plating of distal radius fracture has gained popularity in recent years with the introduction of the locked plating system. Complications of volar plating include extensor and flexor tendon rupture. Here we present a case report of an extensor indicis proprius and extensor digitorum communis to index finger tendon rupture after open reduction and internal fixation of distal radius fracture with locked plate. PMID:23267455

Ward, James P; Kim, L T Suezie; Rettig, Michael E

2012-01-01

38

Locking plates for displaced fractures of the lateral end of clavicle: Potential pitfalls.  

PubMed

Roughly a quarter of all clavicle fractures occur at the lateral end. Displaced fractures of the lateral clavicle have a higher rate of nonunion. The management of fractures of the lateral clavicle remains controversial. Open reduction internal fixation with a superiorly placed locking plate is a recently developed technique. However, there are no randomized controlled trials to evaluate the efficacy of this procedure. We present a series of four cases which highlight the technical drawbacks with this method of fixation for lateral clavicle fractures. Two cases show that failure of the plate to negate the displacing forces at the fracture site can lead to plate pullout. Two cases illustrate an unusual complication of an iatrogenic injury to the acromioclavicular joint capsule which led to joint instability and dislocation. We advise caution in using this method of fixation. Recent studies have described the success of lateral clavicle locking plate fixation augmented with a coracoclavicular sling. This augmentation accounts for the displacing forces at the fracture site. We would recommend that when performing lateral clavicle locking plate fixation, it should be reinforced with a coracoclavicular sling to prevent plate failure by lateral screw pullout. PMID:23493822

Sajid, Soha; Fawdington, Ross; Sinha, Maneesh

2012-10-01

39

Case Report: A Technique to Remove a Jammed Locking Screw from a Locking Plate  

PubMed Central

Background Locking titanium plates revolutionized the treatment of osteoporotic and metaphyseal fractures of long bones. However as with any innovation, with time new complications are identified. One of the problems with titanium locking plates is removal of screws, often attributable to cold welding of screw heads into the locking screw holes. Several techniques have been described to overcome this problem. We describe a new easy technique to remove a jammed locking screw in a locking plate that is easily reproducible and suggest an algorithm to determine the method to remove screws from locking plates. Case Description A 57-year-old man underwent removal of a locking titanium plate from the distal femur. Because the screws could not be readily removed, we used a new technique to remove the jammed locking screws. A radial cut was made in the plate into the locking screw hole and wedged with an osteotome. This released the screw head from the locking screw hole. The screw holes were connected with radial cuts and jammed locking screws were removed in a similar fashion. Literature Review Instruments used for removal of locking screws, including conical extraction screws, hollow reamers, extraction bolts, modular devices, and carbide drill bits, have been described. However, these do not always work. Purposes and Clinical Relevance Removing screws from locking titanium plates can be difficult. There is no method of implant removal that can be universally applied. Therefore, this new technique and our algorithm may be used when removing screws from locking titanium plates.

Dunlop, Colin

2010-01-01

40

Lapidus bunionectomy: Early evaluation of crossed lag screws versus locking plate with plantar lag screw.  

PubMed

We compared outcomes of the Lapidus bunionectomy fixated with crossed lag screws versus a locking plate with a plantar lag screw. Forty patients who underwent Lapidus bunionectomy between August 2001 and May 2006 were evaluated in a combined retrospective and prospective fashion. Crossed lag screws were used in 19 of the patients, and a locking plate with a plantar lag screw was used in 21 of the patients. Other than fixation, the only interventional difference pertained to postoperative weight bearing, where those receiving the plate initiated full weight bearing on the operated foot at 4 weeks postoperative, as compared to 6 weeks for those receiving crossed screws. Overall, the mean preoperative AOFAS hallux score was 41.75 +/- 2.52, and the postoperative score was 90.48 +/- 8.41 (P < .0001). The overall mean preoperative first intermetatarsal angle was 15.3 degrees +/- 2.32 degrees , and long term the angle was 5.03 degrees +/- 2.86 degrees (P < .0001). When comparisons were made based on the method of fixation, use of an adjunct Akin osteotomy and surgery performed before 2003 were statistically significantly associated with crossed screw fixation, and the preoperative AOFAS score was statistically significantly higher in the locking plate fixation group. There were no statistically significant differences related to postoperative complications between the 2 fixation groups. In conclusion, the Lapidus bunionectomy fixated with a locking plate and a plantar lag screw allows earlier weight bearing in comparison with crossed lag screws, without a difference in complications. Level of Clinical Evidence: 2. PMID:19232969

Saxena, Amol; Nguyen, Aidan; Nelsen, Elise

41

Intramedullary nailing versus locked plate for treating supracondylar periprosthetic femur fractures.  

PubMed

The objective of this study was to compare retrograde intramedullary femoral nailing with supracondylar locked screw-plate fixation for the treatment of periprosthetic femur fractures following total knee arthroplasty. Time to union and full weight bearing were the primary study outcomes, with perioperative blood loss, need for transfusion, need for revision surgery, and infection being the secondary outcomes. A retrospective review of 63 patients who sustained Rorabeck Type II periprosthetic femoral fractures was undertaken. Patients were pooled from 3 academic institutions between 2001 and 2009. Patients eligible for the study were identified from the electronic medical record using an IDX query of International Classification of Diseases 9 and Current Procedural Terminology codes for fixation of femur fracture with intramedullary implant or plate and screws. In the series, 35 patients were treated with intramedullary femoral nailing and 28 with a locked screw-plate. The 2 groups were compared for radiographic union at 6, 12, 24, and 36 weeks. At 36 weeks, radiographic union was significantly greater in the locked screw-plate group. Time to full weight bearing was not significantly different. A greater perioperative transfusion rate was observed in the locking plate group, but it also had an overall lower rate of reoperation, for any reason, compared with the intramedullary femoral nailing group. The results support the use of a laterally based locked plate in the treatment of Rorabeck type II distal femur periprosthetic fractures. PMID:23672906

Horneff, John G; Scolaro, John A; Jafari, S Mehdi; Mirza, Amer; Parvizi, Javad; Mehta, Samir

2013-05-01

42

An evaluation of operative management of displaced volar Barton's fractures using volar locking plate.  

PubMed

Volar Barton's fractures are common but more convincing treatment methods are still controversial. Malunion can cause serious disability. Twenty-six consecutive patients were treated with open reduction Internal fixation using volar locking plate. Records of 21 cases were available for follow-up for a mean period of 18 months (range 12-34 months). All 21 fractures healed within 8 to 14 weeks (mean 9.3 weeks). The wrist function was satisfactory in 90.4% cases (19 out of 21 patients). This surgical technique can provide high success rate. Locking plate has better efficacy in terms of immediate stability, maintaining anatomic reduction and early mobilisation. PMID:23785911

Shaw, Ranjit; Shaw, Ranjit Kumar; Mandal, Ananda; Mukherjee, Kunal Subhas; Pandey, Prassana Kumar; Pandey, Prassana

2012-11-01

43

Clinical application of locked plating system in children. An orthopaedic view  

PubMed Central

In recent years, the locked plating system has gained favour in the treatment of certain fractures in adults; however, there is not much information regarding its use in children. We think there could be some advantages and applications such as: an alternative to external fixation, the bridge plating technique, unicortical screws, removal of hardware, metadiaphyseal fractures, periarticular fractures, poor quality bone, and allograft fixation. However, there are some disadvantages to keep in mind and the final decision for using it should be based on the osteosynthesis method principle the surgeon would like to apply. In this review article we discuss the up-to-date possible clinical applications and issues of this system.

Zafra-Jimenez, Jose Alberto; Rodriguez Martin, Juan

2010-01-01

44

Fixation with reconstruction plates under critical conditions: the role of screw characteristics  

Microsoft Academic Search

Mandibular angular ostectomy defects in 12 sheep were bridged with a titanium plate system (THORP), designed according to the screw-plate-locking principle. Two screw designs (hollow and solid) and two rough (plasma-coated, sandblasted)-surface and one smooth (anodized)-surface structure were tested in a critical two-screw anchorage model. Fixation with two screws only per fragment was successful in only one-third of the cases.

Anna-Lisa Söderholm; Berton A. Rann; Kai Skutnabb; Christian Lindqvist

1996-01-01

45

Rotation and plate locking at the southern Cascadia subduction zone  

Microsoft Academic Search

Global Positioning System vectors and surface tilt rates are inverted simultaneously for the rotation of western Oregon and plate locking on the southern Cascadia subduction thrust fault. Plate locking appears to be largely offshore, consistent with earlier studies, and is sufficient to allow occasional great earthquakes inferred from geology. Clockwise rotation of most of Oregon about a nearby pole is

Robert McCaffrey; Maureen D. Long; Chris Goldfinger; Peter C. Zwick; John L. Nabelek; Cheryl K. Johnson; Curt Smith

2000-01-01

46

Development of site-specific locking plates for acetabular fractures.  

PubMed

Site-specific locking plates have gained popularity for the treatment of fractures. However, the clinical use of a site-specific locking plate for acetabular fractures remains untested due to production limits. To design a universal site-specific locking plate for acetabular fractures, the 3-dimensional (3D) photographic records of 171 pelvises were retrospectively studied to generate a universal posterior innominate bone surface. Using 3D photographical processing software, the 3D coordinate system was reset according to bony landmarks and was scaled based on the acetabular diameter to allow a direct comparison between surfaces. The measured surface was separated into measurement units. At each measurement unit, the authors calculated the average z-axis values in all samples and obtained the 3D coordinate values of the point cloud that could be reconstructed into the universal surface. A plate was subsequently designed in 3D photographical processing software, and the orientation and distribution of locking screws was included. To manufacture a plate, the data were entered into Unigraphics NX version 6.0 software (Siemens PLM Software, Co, Ltd, Plano, Texas) and a CNC digital milling machine (FANUC Co, Ltd, Yamanashi, Japan). The resulting locking plate fit excellently with the reduced bone surface intraoperatively. Plate contouring was avoided intraoperatively. Universal 3.5-mm locking screws locked successfully into the plate, and their orientations were consistent with the design. No screw yielded to acetabular penetration. This method of designing a site-specific acetabular locking plate is practical, and the plates are suitable for clinical use. These site-specific locking plates may be an option for the treatment of acetabular fractures, particularly in elderly patients. PMID:23672911

Xu, Meng; Zhang, Li-Hai; Zhang, Ying-Ze; He, Chun-Qing; Zhang, Li-Cheng; Wang, Yan; Tang, Pei-Fu

2013-05-01

47

Results of titanium locking plate and stainless steel cerclage wire combination in femoral fractures  

PubMed Central

Background: Some in vitro studies warn combining different metals in orthopedic surgery. The aim of this study is to determine the impact of combining titanium and stainless steel on bone healing and the clinical course of patients undergoing internal fixation of femoral fractures. Materials and Methods: 69 patients with femoral fractures had polyaxial locking plate osteosynthesis. The locking plate was made of a titanium alloy. Two different cohorts were defined: (a) sole plating and (b) additional stainless steel cerclage wiring. Postoperative radiographs and clinical followup were performed at 6 weeks, 3 months and 12 months. Results: Cohorts A and B had 36 and 33 patients, respectively. Patient demographics and comorbidities were similar in both groups. In two cases in cohort A, surgical revision was necessary. No complication could be attributed to the combination of titanium and stainless steel. Conclusion: The combination of stainless steel cerclage wires and titanium plates does not compromise fracture healing or the postoperative clinical course.

El-Zayat, Bilal Farouk; Ruchholtz, Steffen; Efe, Turgay; Paletta, Jurgen; Kreslo, Dimitri; Zettl, Ralph

2013-01-01

48

Treatment of unstable distal radius fractures with the volar locking plate  

PubMed Central

Background Open reduction and internal fixation using an interlocking plate system has gained popularity for the treatment of dorsally displaced distal radius fractures. Purpose To evaluate the functional and radiological results of treating unstable distal radius fractures with the volar locking plate. Patients and methods A retrospective review was conducted of patients from one institution using the volar locking plate to treat intra-articular and extra-articular distal radius fractures. Unstable distal radius fractures in 15 patients, comprising 3 men and 12 women with a mean age of 64.4 years (34–76 years), were treated with a volar locking compression plate (Acu-Loc distal radius plate system; Acumed, Oregon, USA) and followed up for a minimum of 1 year. Fractures were classified using the AO classification. Radiographic parameters of preoperative, postoperative, and final follow-up radiographs were compared. The time to initiation of active range of motion was determined. Final follow-up range of motion and complications were reported. Results At final functional assessment, the scores of 5 patients were excellent, 7 patients good, and 3 patients fair according to Cooney's Clinical Scoring Chart. No non-union or infection occurred. Rupture of the flexor pollicis longus tendon occurred in 1 patient. Conclusion Treatment of unstable distal radius fractures with a volar locking plate leads to satisfactory results, provided the operative technique is carefully performed to prevent complications.

2011-01-01

49

Periprosthetic Vancouver type B1 and C fractures treated by locking-plate osteosynthesis  

PubMed Central

Background and purpose Historically, the treatment of periprosthetic femoral fractures (PFFs) has been associated with a high frequency of complications and reoperations. The preferred treatment is internal fixation, a revision of the femoral stem, or a combination of both. An improved understanding of plate use during internal fixation, and the introduction of locking-plate osteosynthesis may lead to improved outcome. We evaluated the outcome of Vancouver type B1 and C PFFs treated by locking-plate osteosynthesis, by assessing rates of fracture union and reoperations and by analyzing failure cases. Patients and methods From 2002 through 2011, 58 consecutive patients (60 fractures) with low-energy PFF around or below a stable femoral stem, i.e. Vancouver type B1 and C fractures, underwent osteosynthesis with a locking plate. All patients had a total hip replacement (THR). They were followed up clinically and radiographically, with 6 weeks between visits, until fracture union or until death. Fracture union was evaluated 6 months postoperatively. Results At a median follow-up time of 23 (0–121) months after PFF, 8 patients (8 fractures) had been reoperated due either to infection (n = 4), failure of fixation (n = 3), or loosening of the femoral stem (n = 1). All the patients who had been followed up for at least 6 months—and who did not undergo reoperation or die—went on to fracture union (n = 43). Interpretation Locking-plate osteosynthesis of periprosthetic Vancouver type B1 and C fractures gives good results regarding fracture union. It appears that spanning of the prosthesis to avoid stress-rising areas is important for successful treatment. Infection is the major cause of failure.

2012-01-01

50

The application of holography to examine plated fracture fixation systems  

Microsoft Academic Search

The determination of the real strain patterns across a plated fractured bone is important in developing alternative and improved fracture fixation devices. Bone is strain sensitive, and therefore controlling the displacement or strain at the fracture site or near the fracture plate will effect the bone's response to the fixator. Holographic interferometry is shown to be a useful technique for

J. C. Shelton; D. Gorman; W. Bonfield

1990-01-01

51

CORR Insights: Locking buttons increase fatigue life of locking plates in a segmental bone defect model.  

PubMed

This CORR Insights™ is a commentary on the article "Locking Buttons Increase Fatigue Life of Locking Plates in a Segmental Bone Defect Model" by Tompkins et al. available at DOI 10.1007/s11999-012-2664-1 . PMID:23242826

Schnaser, Erik; Vallier, Heather

2012-12-14

52

Finite element analysis of Puddu and Tomofix plate fixation for open wedge high tibial osteotomy.  

PubMed

The use of open wedge high tibial osteotomy (HTO) to correct varus deformity of the knee is well established. However, the stability of the various implants used in this procedure has not been previously demonstrated. In this study, the two most common types of plates were analysed (1) the Puddu plates that use the dynamic compression plate (DCP) concept, and (2) the Tomofix plate that uses the locking compression plate (LCP) concept. Three dimensional model of the tibia was reconstructed from computed tomography images obtained from the Medical Implant Technology Group datasets. Osteotomy and fixation models were simulated through computational processing. Simulated loading was applied at 60:40 ratios on the medial:lateral aspect during single limb stance. The model was fixed distally in all degrees of freedom. Simulated data generated from the micromotions, displacement and, implant stress were captured. At the prescribed loads, a higher displacement of 3.25 mm was observed for the Puddu plate model (p<0.001). Coincidentally the amount of stresses subjected to this plate, 24.7 MPa, was also significantly lower (p<0.001). There was significant negative correlation (p<0.001) between implant stresses to that of the amount of fracture displacement which signifies a less stable fixation using Puddu plates. In conclusion, this study demonstrates that the Tomofix plate produces superior stability for bony fixation in HTO procedures. PMID:22204773

Raja Izaham, Raja Mohd Aizat; Abdul Kadir, Mohammed Rafiq; Abdul Rashid, Abdul Halim; Hossain, Md Golam; Kamarul, T

2011-12-27

53

Far cortical locking technology for fixation of periprosthetic distal femur fractures: a surgical technique.  

PubMed

Far cortical locking screws have been shown to form greater amounts of callus in ovine studies when compared to traditional locking plates. These screws have recently become available for clinical use. This article describes the indications and surgical technique for far cortical locking screws, with a focus on distal femur periprosthetic fractures. PMID:23408343

Ries, Zachary G; Marsh, J L

2013-02-13

54

Failure analysis of stainless steel femur fixation plate.  

PubMed

Failure analysis was performed to investigate the failure of the femur fixation plate which was previously fixed on the femur of a girl. Radiography, metallography, fractography and mechanical testing were conducted in this study. The results show that the failure was due to the formation of notches on the femur plate. These notches act as stress raisers from where the cracks start to propagate. Finally fracture occurred on the femur plate and subsequently, the plate failed. PMID:15468877

Hussain, P B; Mohammad, M

2004-05-01

55

TRACE METAL ANALYSIS FOLLOWING LOCKED VOLAR PLATING FOR UNSTABLE FRACTURES OF THE DISTAL RADIUS  

PubMed Central

An increase in the utilization of metallic devices for orthopaedic interventions from joint replacement to fracture fixation has raised concern over local metal ion release and possible systemic sequelae due to dissemination of these ions. Our purpose was to determine whether serum titanium concentrations were elevated in patients who had previously received a locked volar distal radius plate. Our hypothesis was that the simple presence of titanium alone in a relatively fixed implant was not enough to raise serum titanium levels. Twenty-two potential subjects who had received a volar locked distal radius plate were identified through review of a single surgeon's operative logs. Eleven met inclusion criteria. Serum titanium levels were measured in these subjects and compared to both current and historical control groups. We found no difference between controls and our study group with the exception of one control subject who is employed as a welder. This is in contrast to previous studies from our institution which found increases in titanium levels in hip and spine implants. We conclude that a locking titanium volar distal radius plate does not raise serum titanium levels in this population.

Rylander, Lucas S; Milbrandt, Joseph C; Armington, Evan; Wilson, Marty; Olysav, David J

2010-01-01

56

Proximal Humeral Fractures: A Biomechanical Comparison of Locking Plate Constructs in a Cadaveric 3Part Fracture Model  

Microsoft Academic Search

The purpose of our study was to biomechanically compare, under cyclic loading conditions, fracture site motion, humeral head collapse, and intra-articular hardware penetration in simulated 3-part osteoporotic proximal humeral fractures stabilized with 1 of 2 locking-plate constructs. We performed fixation on simulated 3-part proximal humeral fractures in 10 pairs of cadaveric osteoporotic humeri with a Hand Innovations S3 Proximal Humerus

David M. Rose; Edward G. Sutter; Simon C. Mears; Rohit R. Gupta; Stephen M. Belkoff

2010-01-01

57

Effectiveness of a locking plate in preserving midcalcaneal length and positional outcome after evans calcaneal osteotomy: a retrospective pilot study.  

PubMed

When using the Evans calcaneal osteotomy for repair of a calcaneovalgus deformity, lengthening of the lateral column of the foot is the method by which the procedure acts to correct the deformity. Therefore, maintaining the length is a priority. In our experience, substantial length is lost soon after surgery using the traditional nonfixated procedure. To test this hypothesis, a retrospective study was undertaken in which we compared the calcaneal length before and after the Evans procedures in 22 patients treated without fixation and 13 patients in whom the graft was fixated with a small locking plate to bridge the osteotomy and reduce the compressive forces on the graft. Within the first 10 days after surgery, the increase in calcaneal length from the preoperative length was 6.3 mm in the nonfixated group and 6.8 mm in the fixated group (p = .54 for the 0.5-mm difference). At 12 weeks after surgery, the mean amount of shortening from the value observed at 1 week was 2.45 (range 0 to 6) mm in the nonfixated group and 1.0 (range 0 to 3) mm in the internal fixation group (p = .48). Also, at 12 weeks, distal calcaneal migration or dorsal anterior calcaneal displacement of more than 3 mm occurred in 5 patients (23%) in the nonfixated group and 1 patient (8%) in the fixated group (p = .04). Our results suggest that locking plates do preserve the correction obtained with the Evans calcaneal osteotomy. PMID:23800574

Dayton, Paul; Prins, Dustin B; Smith, David E; Feilmeier, Mindi J

2013-06-22

58

Biomechanical effects of screw fixation in second mandibular reconstruction plate.  

PubMed

The purpose of this study was to investigate biomechanical effects of second reconstruction plate with different combinations of fixed screws in patient with mandibular tumor resection by three-dimensional finite element analysis (FEA). The FEA models were consisted of defected mandible, reconstruction plate with different screw holes, and bone screws. The results indicated that application of the second reconstruction plate appeared to increase stability and decrease stress magnitude on the plates and screws accompanying with increasing screw number. For clinical cost consideration in usage of the second reconstruction plate, the conclusion showed that the second reconstruction plate could offer a better mechanical efficacy accompanying with increase of screw quantity, but single screw applied for the second plate fixation to defected mandible of tumor resection was enough to stabilize without increase of screw quantities. PMID:24110400

Chang, Ya-Wen; Liu, Pao-Hsin

2013-07-01

59

LCP distal ulna hook plate as alternative fixation for fifth metatarsal base fracture.  

PubMed

Intramedullary screw fixation is the most common treatment for fifth metatarsal base fractures. Screw application does not achieve accurate reduction in fracture with small fragments, osteoporotic bone, or Lawrence zone 1 fractures, however. On the basis of similar anatomical architectures between the distal ulna and the fifth metatarsal base, the purpose of this study was to assess the results of a locking compression plate (LCP) distal ulna hook plate in stabilizing displaced zone 1 or 2 fifth metatarsal base fractures. Nineteen patients with Lawrence zone 1 (n = 12) or 2 (n = 7) fractures of the fifth metatarsal base were treated surgically with an LCP distal ulna hook plate. The patients were evaluated clinically and radiographically, and functional outcomes were graded by using the American Orthopaedic Foot and Ankle Society (AOFAS) midfoot scoring system. Radiographic bony union was obtained in all patients, at an average of 7.4 weeks. The mean AOFAS midfoot score improved from 26 (range, 0-45) preoperatively to 94 (range, 72-100) points at the final follow-up. There were three patients with post-traumatic cubometatarsal arthrosis and one patient with sural nerve neuropraxia. In our experience, the distal ulna hook plate achieves a high rate of bony consolidation and anatomically suitable fixation in zone 1 or 2 fifth metatarsal base fractures. We also suggest that the LCP distal ulna hook plate should be considered as an alternative treatment in multifragmentary, osteoporotic, and tuberosity avulsion (zone 1) fifth metatarsal base fractures. PMID:23412193

Lee, Sang Ki; Park, Ju Sang; Choy, Won Sik

2012-08-22

60

Plate and screw fixation for atlanto-axial subluxation  

Microsoft Academic Search

Summary Our experience with 30 cases of atlanto-axial dislocation, over the period of 3 years and 9 months, is described. A modified plate and screw method of fixation of the lateral masses of the atlas and axis was successfully used in these cases. The technical aspects and merits of the method, wherein a 100% union rate was achieved, with no

A. Goel; V. Laheri

1994-01-01

61

Plate fixation for anterior cervical interbody fusion.  

PubMed

From April 1989 to April 1990, 13 patients with cervical spinal fracture/dislocation, spondylosis or metastasis were treated at the respective hospitals. There were 4 women and 9 men whose ages ranged from 25 to 70 years (mean 45 years). All of them were treated with neural decompression, bone grafting and anterior spinal interbody fusion. All iliac crest or fibular bone grafts were anchored to the vertebral bodies with plates and screws. The clinical outcomes were evaluated retrospectively. The results showed that all had improvement of neurological symptoms and signs. The radiographic evaluation revealed satisfactory alignment and sound union of the cervical spine in all 13 patients. No serious complications were found except screw loosening in two instances without impairment of clinical results. We concluded that anterior cervical plates provide effective stabilization which is essential for good results. Furthermore, from this study and a review of the literature, we advocated that it was not necessary for the tip of the screws to reach or even penetrate the posterior cortex of the vertebral body. PMID:1678412

Chen, I H; Yang, R S; Chen, P Q

1991-02-01

62

Operative outcome of unstable lower cervical fracture dislocation by lateral mass screw fixation or anterior plating.  

PubMed

From February 2009 to September 2012, 15 patients (13 males, 2 females; age range, 18-55 years) with the lower cervical fracture dislocation were treated at NRS Medical College, Kolkata. The fracture dislocation occurred in the following cervical segments: C5 (n = 8), C7 (n = 3), C4 (n = 2), and C6 (n = 2). Forteen patients were associated with neurological deficit graded according to ASIA impairment scale. The time interval between Injury and operation was from 3 to 22 days. Eight patients underwent anterior fusion with anterior locked-cervical plate fixation; 7 patients underwent posterior fusion and the lateral mass screw fixation. During each follow-up clinical and radiological parameters were measured; bone fusion and internal fixation condition were observed by x-ray and the neurological recovery was measured by ASIA impairment scale. Follow-up duration was from 3 months to 30 months in different patients which revealed fusion between vertebrae and significant neurological recovery. The fusion time was 4 to 6 months and there was also no instability of vertebrae or loosening of the internal fixation at 12 months. The selection of operative treatment of subaxial cervical spine injury depends upon neurological and radiological criteria. Both posterior and anterior surgical approaches are viable alternatives for treating subaxial spine injuries with different indication and risk profiles. In case of incomplete neurological injury there is significant improvement. Operative treatment certainly decreases the complications related to prolonged immobilisation in recovery phase by making the patient mobile early. PMID:23785912

Sarkar, Partha Sarathi; Mukhopadhyay, Kiran Kumar; Bera, Amiya Kumar; Latif, Abdul

2012-11-01

63

Biomechanical failure of metacarpal fracture resorbable plate fixation.  

PubMed

Metacarpal fractures are a relatively common hand injury that may require operative intervention to ensure adequate reduction and stabilization. The use of permanent hardware, although acceptable, may lead to complications and an increased number of surgical procedures. The use of resorbable hardware such as poly-L-lactic acid and polyglycolic acid copolymer plates and screws may circumvent some of these complications. In vitro studies have demonstrated that the biomechanical characteristics of these resorbable plates may provide the rigid fixation necessary to allow for union of metacarpal fractures in vivo. However, limited clinical data are available regarding the success of their use in this application. The authors present what they believe is the first reported case of the failure of a poly-L-lactic acid and polyglycolic acid copolymer miniplate after use in the fixation of a metacarpal shaft fracture. PMID:12187350

Lionelli, Gerald T; Korentager, Richard A

2002-08-01

64

Aramid-epoxy composite internal fixation plates: a pilot study.  

PubMed

Mechanical tests were conducted on an aramid-epoxy composite laminate in vitro and in vivo to determine its suitability for internal fixation plates. This material, fashioned into blank test coupons the size of the standard 4-hole AO-ASIF plates, had a tensile modulus of elasticity significantly lower than bone. In three-point bending, blank test coupons exhibited a low yield strength that would limit utility in significant load-bearing situations, but changes in the layer configuration of the composite could be expected to improve this characteristic. Under destructive loads, these specimens appeared to be less subject to catastrophic failure than carbon fibre composites. Using 4-hole test coupons fastened to a plastic tube simulating bone, four-point bending tests showed that strain-shielding was significantly reduced by aramid composite relative to carbon fibre composite or metal plates. Finally, in-vivo tests on canine femora demonstrated that aramid composite plates were well tolerated and caused less strain shielding during weightbearing, but significant differences in cortical atrophy and porosity beneath steel versus aramid plates were not apparent. Although the plates were relatively flexible, they could not be preformed during surgery like a metal plate. PMID:23916301

Cochran, G V; Palmieri, V R; Zickel, R E

1994-09-01

65

A new volar plate DiPhos-RM for fixation of distal radius fracture: preliminary report.  

PubMed

We analyzed the efficiency of a new plate DiPhos-RM in CFR-PEEK [carbon-fiber-reinforced poly (etheretherketone)] for the volar fixation of distal radius fractures. The new plate's composition has the advantage of x-ray absolute transparency, therefore allowing to monitor the healing of the fracture. The desired combination of high strength and low rigidity is obtained through the use of the polymer composites CFR-PEEK. In this preliminary study (from March 2012 to June 2012), 10 cases of intra-articular distal radius fractures were treated with DiPhos-RM produced by Lima Corporate (Italy). The fractures were classified according to the AO classification, 4 fractures were type C1, 3 type C2, and 3 were A2. A preoperative computed tomography scan was carried out in all patients. One patient also underwent a postoperative computed tomography scan. Grip strength, range of motion, and DASH score were evaluated at follow-up. There were no cases of hardware failure. Specifically, no loss of position or alignment of fixed-angle locking screws or breakage of the plate were observed. Radiographic union was present at an average of 6 weeks (range, 5 to 8 wk). The overall preliminary experience with this new plate is favorable. The new plate is easy to apply and provides the surgeon dual options of fixed-angle or variable-angle screws. It was rigid enough to maintain the reduction also in AO type C articular fractures. PMID:23423235

Tarallo, Luigi; Mugnai, Raffaele; Adani, Roberto; Catani, Fabio

2013-03-01

66

Treatment of extra-articular and simple articular distal radial fractures with intramedullary nail versus volar locking plate.  

PubMed

The purpose of this prospective, randomized and blinded study was to compare the clinical outcomes of distal radial fractures treated with either an intramedullary nail or a volar locking plate. Sixty two patients were enrolled in the study and randomized to treatment with a MICRONAILTM (Group 1, 31 patients) or an adaptive plate (Group 2, 31 patients). Fracture types included were unstable extra-articular metaphyseal distal radial fractures and simple or multifragmentary sagittal articular distal radial fractures (AO classification types A2, A3, B1.1 and B1.2). All patients were evaluated at 6 weeks, 3 months and 12 months after surgery. Outcome measures included standard radiographic parameters, active wrist range of motion, the disabilities of the arm, shoulder and hand (DASH) and Mayo wrist scores. We concluded that treatment of this subset of distal radius fractures with minimally invasive intramedullary nailing gives better clinical outcomes at 6 weeks after surgery than treatment with a volar locking plate. By 3 and 12 months following surgery, there are no significant differences in outcome between the two treatment methods. Disadvantages of the MICRONAIL™ fixation system include risk of injury to the superficial branch of the radial nerve and a narrower spectrum of indications than volar locking plates. PMID:23442339

Safi, A; Hart, R; Teknedzjan, B; Kozák, T

2013-02-26

67

Biomechanics of Far Cortical Locking  

PubMed Central

The development of FCL was motivated by a conundrum: locked plating constructs provide inherently rigid stabilization, yet they should facilitate biological fixation and secondary bone healing that relies on flexible fixation to stimulate callus formation. Recent studies have confirmed that the high stiffness of standard locked plating constructs can suppress interfragmentary motion to a level that is insufficient to reliably promote secondary fracture healing by callus formation. Furthermore, rigid locking screws cause an uneven stress distribution that may lead to stress fracture at the end screw and stress shielding under the plate. This review summarizes four key features of FCL constructs that have shown to enhance fixation and fracture healing: Flexible fixation, load distribution, progressive stiffening, and parallel interfragmentary motion. Specifically, flexible fixation provided by FCL reduces the stiffness of a locked plating construct by 80–88% to actively promote callus proliferation similar to an external fixator. Load distribution is evenly shared between FCL screws to mitigate stress risers at the end screw. Progressive stiffening occurs by near cortex support of FCL screws and provides additional support under elevated loading. Finally, parallel interfragmentary motion by s-shaped flexion of FCL screws has shown to induce symmetric callus formation. In combination, these features of FCL constructs have shown to induce more callus and to yield significantly stronger and more consistent healing compared to standard locked plating constructs. As such, FCL constructs function as true internal fixators by replicating the biomechanical behavior and biological healing response of external fixators.

Bottlang, Michael; Feist, Florian

2011-01-01

68

The relationship between porosity, collagen fiber orientation and strength of plated bone after rigid plate fixation and removal.  

PubMed

OBJECTIVE: To understand the relationship between porosity, collagen fiber orientation and strength of the plated bone after rigid plate fixation and removal. METHODS: Seventy-two New Zealand white rabbits were used in this experiment. Eight animals served as control and the other sixty-four were plated on their intact left tibiae with stainless steel (316L) 4-hole plates to induce early osteoporosis. The plates were removed 2 months after internal fixation in 40 plated animals, 8 of which were sacrificed immediately following plate removal and the other 32 were killed in successive groups with 8 in each group 1, 2, 3 and 4 months after plate removal. The remaining 24 plated animals were killed at 3, 4 and 6 months after plate fixation. After sacrifice, the samples of plated bone were prepared for light microscope, quantitative histological analysis, polarized light microscope and biomechanical test. RESULTS: The internal fixation with a rigid plate could induce the regional osteoporosis which manifested both bone loss and disorganized bone structure (loss of the orientation of the collagen fibers) leading to decreased strength of the plated bone. Although the regional osteoporosis could recover gradually after plate removal, the bone structure remained disorderly even when the bone mass returned to normal. Delayed restoration of bone structure was related to delayed restoration of bone strength. CONCLUSIONS: Besides the bone loss, the disorganized bone structure is the main cause of decrease of bone strength after rigid plate fixation and removal. PMID:11900663

Zhu, Zhen'an; Dai, Kerong; Qin, Shijing; Chen, Yongqiang

1999-11-15

69

Isolated locked compression plating for Vancouver Type B1 periprosthetic femoral fractures  

Microsoft Academic Search

ObjectiveReport treatment results of periprosthetic femoral fractures adjacent or at the tip of a stable femoral stem (Vancouver Type B1) using a locked compression plate as the sole method of fracture stabilisation.

Ginger K. Bryant; Saam Morshed; Julie Agel; M. Bradford Henley; David P. Barei; Lisa A. Taitsman; Sean E. Nork

2009-01-01

70

Effectiveness of locking versus dynamic compression plates for diaphyseal forearm fractures.  

PubMed

This study compares the results of the locking compression plate (LCP) and the dynamic compression plate (DCP) in the treatment of diaphyseal forearm fractures in adults and defines the indications for the use of the LCP. Forty-two patients with diaphyseal forearm fractures were retrospectively analyzed. Of those, 22 had been treated with the LCP (LCP group) and 20 had been treated with the DCP (DCP group). The AO/ASIF classification was used to classify the fractures. Patients were assessed using the Grace-Eversmann criteria and the Disabilities of the Arm and Shoulder and Hand questionnaire during the final follow-up. Mean follow-up was 21 months (range, 20-24 months) in the LCP group and 23 months (range, 19-26 months) in the DCP group. Union was achieved in all patients. Mean time to union was 15 weeks (range, 12-25 weeks) in the LCP group and 17 weeks (range, 13-24 weeks) in the DCP group. In each group, 1 patient experienced delayed union, which required no additional surgical intervention. No significant difference was found regarding the time to union between the groups (P>.05). No significant difference existed between the 2 groups in terms of Grace-Eversmann criteria and Disabilities of the Arm and Shoulder and Hand scores (both P>.05). The results of these different fixation methods for forearm fractures in adults are similar. As such, the correct selection and application of surgical technique is more important than the type of plate used. PMID:23823050

Azboy, Ibrahim; Demirtas, Abdullah; Uçar, Bekir Yavuz; Bulut, Mehmet; Alemdar, Celil; Ozkul, Emin

2013-07-01

71

The dynamisation of locking plate osteosynthesis by means of dynamic locking screws (DLS)-An experimental study in sheep.  

PubMed

In this in vivo study a new generation of locking screws was tested. The design of the dynamic locking screw (DLS) enables the dynamisation of the cortex underneath the plate (cis-cortex) and, therefore, allows almost parallel interfragmentary closure of the fracture gap. A 45° angle osteotomy was performed unilaterally on the tibia of 37 sheep. Groups of 12 sheep were formed and in each group a different osteotomy gap (0, 1 and 3mm) was fixed using a locking compression plate (LCP) in combination with the DLS. The healing process was monitored radiographically every 3 weeks for 6, respectively 12 weeks. After this time the sheep were sacrificed, the bones harvested and the implants removed. The isolated bones were evaluated in the micro-computed tomography unit, tested biomechanically and evaluated histologically. The best results of interfragmentary movement (IFM) were shown in the 0mm configuration. The bones of this group demonstrated histomorphometrically the most distinct callus formation on the cis-cortex and the highest torsional stiffness relative to the untreated limb at 12 weeks after surgery. This animal study showed that IFM stimulated the synthesis of new bone matrix, especially underneath the plate and thus, could solve a current limitation in normal human bone healing. The DLS will be a valuable addition to the locking screw technology and improve fracture healing. PMID:23182750

Plecko, Michael; Lagerpusch, Nico; Andermatt, Daniel; Frigg, Robert; Koch, Rudolf; Sidler, Michèle; Kronen, Peter; Klein, Karina; Nuss, Katja; Bürki, Alexander; Ferguson, Stephen J; Stoeckle, Ulrich; Auer, Jörg A; von Rechenberg, Brigitte

2012-11-24

72

A systematic review of plate versus intramedullary fixation in the treatment of midshaft clavicle fractures.  

PubMed

The best method of fixation for clavicle fractures is not known. The purpose of this review was to examine the evidence comparing plate and intramedullary fixation for midshaft clavicle fractures. A search of MEDLINE in September 2011 identified five papers that compared plate and intramedullary fixation, and fulfilled our eligibility criteria, consisting of; one randomised controlled trial, two quasi-randomised controlled trials, and two retrospective studies. Level of evidence was assessed using the Scottish Intercollegiate Guidelines Network guidance and the Cochrane Bone, Joint and Muscle Trauma Group's quality assessment tool. No attempt at meta-analysis was made due to the heterogeneity of the study populations and interventions. We found no difference between intramedullary fixation and plate fixation. There was a trend towards a lower complication rate with intramedullary fixation. On the basis of the available evidence, we would advocate both techniques for the treatment of midshaft clavicle fractures. PMID:23960055

Barlow, T; Beazley, J; Barlow, D

2013-08-01

73

Design of Fracture Fixation Plate for Necessary and Sufficient Bone Stress Shielding  

NASA Astrophysics Data System (ADS)

The objective of treating the fractured bone is to achieve painless functioning of the bone and undisturbed healing at the fracture. Internal fixation by stiff bone-plate is one of the standard methods to achieve these objectives. Recently, there is considerable interest in the usage of compliant plates to enhance bone healing with reduced stress shielding. Herein, first an analytical solution is developed to determine screw forces in the bone-plate assembly that conforms the plate and the bone under bending load. Based on the analytical calculations, an optimal fixator plate selection criterion for necessary and sufficient stress shielding is proposed. Second, effectiveness of employing a non-homogeneous stiffness graded (SG) plate rather than a homogeneous stainless steel (SS) plate for stress shielding is investigated using a finite element method. It is found that stress shielding on bone by SG plate is less compared to SS plate.

Ramakrishna, Kotlanka; Sridhar, Idapalapati; Sivashanker, Sathiamoorthy; Khong, Kok Sun; Ghista, Dhanjoo N.

74

Comparative study of ankle arthrodesis using cross screw fixation versus anterior contoured plate plus cross screw fixation.  

PubMed

Arthrodesis of the ankle joint is still the traditional treatment for symptomatic osteoarthritis. This comparative study was done to assess the functional outcome of open ankle fusion using either cross screw fixation (group A) or anterior contoured plate and cross screw fixation (group B) in a consecutive series of 22 patients. All the patients had the same inclusion criteria. All the patients in both groups underwent the same operative technique and were operated by the same surgeon. Mean follow-up was 26.8 months. The mean time to fusion was 18.8 weeks in group A and 16.8 weeks in group B (p = 0.046). The mean American Orthopaedic Foot and Ankle Society (AOFAS) Ankle and Hind foot score at the final follow-up was 79 in group A and 86 in group B (p = 0.23). Two patients in group A that went to non-union required re-arthrodesis using contoured plate and cross screw fixation; both attained eventual union. We conclude that anterior contoured plate plus cross screw fixation is a simple and reproducible technique for ankle arthrodesis that gives stable internal fixation and excellent clinical results. PMID:17260609

Kakarala, Gopikrishna; Rajan, Daniel T

2006-12-01

75

Comparison of a new minimum contact locking plate and the limited contact dynamic compression plate in an osteoporotic fracture model  

Microsoft Academic Search

The purpose of this study was to investigate the biomechanical properties of a new minimum contact locking plate (MC-LP) compared\\u000a with the limited contact dynamic compression plate (LC-DCP). Eighteen pairs of fresh human osteoporotic cadaver radii were\\u000a equally divided into three groups. Each specimen was tested in each of the following force applications: anteroposterior (AP)\\u000a four point bending, mediolateral (ML)

Yan Xiong; Yufeng Zhao; Ziming Wang; Quanyin Du; Weijun Chen; Aimin Wang

2009-01-01

76

Design and experimental evaluation of adjustable bone plates for mandibular fracture fixation.  

PubMed

Conventional bone plates are commonly used for surgical mandibular fracture fixation. Improper alignment between bone segments, however, can result in malocclusion. Current methods of fixation require a surgeon to visually align segments of bone and affix a metal plate using bone screws, after which little can be done to adjust alignment. A method of adjusting fracture alignment after plate placement, without screw removal, presents an improvement over costly and risky revision surgery. A modified bone plate has been designed with a deformable section to give surgeons the ability to reduce misalignments at the fracture site. The mechanics of deformation for various adjustment mechanisms was explored analytically, numerically, and experimentally to ensure that the adjustable plate is comparable to conventional bone plates. A static force of 358.8 N is required to deform the adjustable bone plate, compared with predicted values of 351 N using numerical simulation and 362 N using a simple beam theory. Dynamic testing was performed to simulate in vivo loading conditions and evaluate load-capacity in both deformed and un-deformed bone plates. Results indicate that bending stiffness of a rectangular bone plate is 709 N/mm, compared with 174 N/mm for an octagonal plate and 176 N/mm for standard plates. Once deformed, the rectangular and octagonal plates had a stiffness of 323 N/mm and 228 N/mm, respectively. Un-deformed and deformed adjustable bone plates have efficacy in bone segment fixation and healing. PMID:22036033

Cervantes, Thomas M; Slocum, Alexander H; Seldin, Edward B

2011-10-28

77

Precontoured Superior Locked Plating of Distal Clavicle Fractures: A New Strategy  

Microsoft Academic Search

Background  The ideal management of fractures of the distal third of the clavicle remains a topic of debate. Locked plating is a new treatment\\u000a method but is not yet widely studied.\\u000a \\u000a \\u000a \\u000a \\u000a Questions\\/purposes  We therefore determined union rates, function, and complications treated with locked plating.\\u000a \\u000a \\u000a \\u000a Patients and Methods  We retrospectively reviewed 20 patients with Neer Type II distal clavicle fractures. All patients were treated

Jaron R. Andersen; Matt P. Willis; Ryan Nelson; Mark A. Mighell

78

Finite element stress analysis of a hybrid fracture fixation plate  

Microsoft Academic Search

Metal plates are commonly used in the operative treatment of bone fractures. Rigid metal plates stabilize the fracture site, maintain good contact between bone fragments and allow early weight bearing and patient mobility. However, treatment with rigid metal plates can cause localized bone atrophy due to stress-shielding and interference with blood circulation, and the weakened bone can refracture after plate

S. J. Ferguson; U. P. Wyss; D. R. Pichora

1996-01-01

79

Interseismic locking of the plate interface in the northern Cascadia subduction zone, inferred from inversion of GPS data  

Microsoft Academic Search

We inverted GPS velocities from 20 continuous and 53 campaign sites in the northern Cascadia subduction zone using a Bayesian inverse method to estimate the locking state of the plate interface. The results are consistent with previous estimates based on thermal arguments and forward modeling. They suggest that the completely locked segment of the plate interface is offshore and that

Shoichi Yoshioka; Kelin Wang; Stephane Mazzotti

2005-01-01

80

An off-loading triceps suture for augmentation of plate fixation in comminuted osteoporotic fractures of the olecranon.  

PubMed

Comminuted osteoporotic olecranon fractures in the elderly are relatively common. Open reduction and internal plate fixation is a frequently used treatment option. In highly comminuted osteoporotic bone, fixation may be tenuous leading to an increased risk of fixation failure with loss of reduction and displacement of fracture fragments. The off-loading triceps suture technique is a load-sharing mechanism to decreases distraction forces caused by the extensor mechanism on comminuted osteopenic olecranon fracture fragments managed with plate fixation. PMID:22025265

Izzi, Joseph; Athwal, George S

2012-01-01

81

Corrective Osteotomy for Deformity of the Distal Radius Using a Volar Locking Plate  

Microsoft Academic Search

Dorsally angulated malunions of the distal radius have historically been corrected with an opening wedge osteotomy fixed with\\u000a a dorsal plate. Volar locking plates may facilitate a less morbid approach to corrective osteotomies of the wrist. Eight consecutive\\u000a patients with an average age of 40 years (range, 15–52 years) underwent correction of a distal radius deformity through a\\u000a volar approach. Clinical follow-up

Brett Peterson; Varun Gajendran; Robert M. Szabo

2008-01-01

82

A locking-free meshless local Petrov Galerkin formulation for thick and thin plates  

NASA Astrophysics Data System (ADS)

In this paper, a locking-free meshless local Petrov Galerkin formulation is presented for shear flexible thick plates, which remains theoretically valid in the thin-plate limit. The kinematics of a three-dimensional solid is used, instead of the conventional plate assumption. The local symmetric weak form is derived for cylindrical shaped local sub-domains. The numerical characteristics of the local symmetric weak form, in the thin plate limit, are discussed. Based on this discussion, the shear locking is theoretically eliminated by changing the two dependent variables in the governing equations. The moving least square interpolation is utilized in the in-plane numerical discretization for all the three displacement components. In the thickness direction, on the other hand, a linear interpolation is used for in-plane displacements, while a hierarchical quadratic interpolation is utilized for the transverse displacement, in order to eliminate the thickness locking. Numerical examples in both the thin plate limit and the thick plate limit are presented, and the results are compared with available analytical solutions.

Li, Q.; Soric, J.; Jarak, T.; Atluri, S. N.

2005-09-01

83

Biomechanical stability of a supra-acetabular pedicle screw Internal Fixation device (INFIX) vs External Fixation and plates for vertically unstable pelvic fractures  

PubMed Central

Background We have recently developed a subcutaneous anterior pelvic fixation technique (INFIX). This internal fixator permits patients to sit, roll over in bed and lie on their sides without the cumbersome external appliances or their complications. The purpose of this study was to evaluate the biomechanical stability of this novel supraacetabular pedicle screw internal fixation construct (INFIX) and compare it to standard internal fixation and external fixation techniques in a single stance pelvic fracture model. Methods Nine synthetic pelves with a simulated anterior posterior compression type III injury were placed into three groups (External Fixator, INFIX and Internal Fixation). Displacement, total axial stiffness, and the stiffness at the pubic symphysis and SI joint were calculated. Displacement and stiffness were compared by ANOVA with a Bonferroni adjustment for multiple comparisons Results The mean displacement at the pubic symphysis was 20, 9 and 0.8?mm for external fixation, INFIX and internal fixation, respectively. Plate fixation was significantly stiffer than the INFIX and external Fixator (P?=?0.01) at the symphysis pubis. The INFIX device was significantly stiffer than external fixation (P?=?0.017) at the symphysis pubis. There was no significant difference in SI joint displacement between any of the groups. Conclusions Anterior plate fixation is stiffer than both the INFIX and external fixation in single stance pelvic fracture model. The INFIX was stiffer than external fixation for both overall axial stiffness, and stiffness at the pubic symphysis. Combined with the presumed benefit of minimizing the complications associated with external fixation, the INFIX may be a more preferable option for temporary anterior pelvic fixation in situations where external fixation may have otherwise been used.

2012-01-01

84

Limb lengthening for post-traumatic shortening over a pre-implanted femoral locking plate.  

PubMed

Attempts have been made to refine techniques involved in distraction osteogenesis to improve patient compliance and reduce complications. The prolonged use of external fixators for limb lengthening is associated with a number of problems, and in addition patient satisfaction with a cumbersome external fixator may be low. To reduce the complication rate and facilitate early removal of the external fixator by protecting the regenerate bone, lengthening over an intramedullary nail is being increasingly described. These techniques have limitations when used in skeletally immature patients and carry a risk of deep intramedullary infection. Post-traumatic limb length discrepancy is not uncommon after high-energy injuries are fixed in a shortened position secondary to bone loss. The plate applied at the time of injury may be incorporated into any subsequent lengthening process. A detailed description of the technique of lengthening over a pre-implanted distal femoral plate is followed by presentation of 2 case examples. PMID:22648038

Kosuge, Dennis D; Pugh, Hannah; Timms, Anna; Barry, Matthew

2013-03-01

85

[Biomechanical evaluation of titanium mesh with anterior plate fixation in anterior cervical decompression].  

PubMed

We have made a biomechanical evaluation of titanium mesh with anterior plate fixation in anterior cervical decompression. Six fresh cervical spine specimens (C3-7) of young cadavers were used in the biomechanical test. Subtotal vertebrectomy was performed on C5, C5-6 and C4-6. We accomplished two constructions: (1) bone graft; (2) titanium mesh with anterior plate fixation. Then their biomechanic stabilities were tested in all groups and compared with those of intact specimens. We found that titanium mesh with anterior plate fixation improved the stability of the unstable spine, showing a significant difference when compared with that of the intact group (P < 0.05). The anterior cervical interbody fusion by bone graft and the titanium mesh implantation is stabler than the intact cervical sample, and the stability decreases with the increase in number of cervical segment. PMID:17591251

Cao, Yongfei; Zhao, Zhuchuan; Peng, Zhi; Zhang, Meixin; Chen, Mengshi

2007-04-01

86

Assessment of carbon fibre composite fracture fixation plate using finite element analysis.  

PubMed

In the internal fixation of fractured bone by means of bone-plates fastened to the bone on its tensile surface, an on-going concern has been the excessive stress shielding of the bone by the excessively-stiff stainless-steel plate. The compressive stress shielding at the fracture-interface immediately after fracture-fixation delays callus formation and bone healing. Likewise, the tensile stress shielding in the layer of bone underneath the plate can cause osteoporosis and decrease in tensile strength of this layer. In this study a novel forearm internal fracture fixation plate made from short carbon fibre reinforced plastic (CFRP) was used in an attempt to address the problem. Accordingly, it has been possible to analyse the stress distribution in the composite plates using finite-element modelling. A three-dimensional, quarter-symmetric finite element model was generated for the plate system. The stress state in the underlying bone was examined for several loading conditions. Based on the analytical results the composite plate system is likely to reduce stress-shielding effects at the fracture site when subjected to bending and torsional loads. The design of the plate was further optimised by reducing the width around the innermost holes. PMID:16732432

Saidpour, Seyed H

2006-05-27

87

Processing and evaluation of long fiber thermoplastic composite plates for internal fixation  

NASA Astrophysics Data System (ADS)

The metallic plates used in internal fracture fixation may have up to ten times the elastic modulus of normal bone tissue, causing stress shielding-induced osteopenia in healed bone that can lead to re-fracture after plate removal and prolonged and painful recovery. Thermoplastic polymer matrix composites reinforced with long carbon fiber are promising alternative materials for internal fixation plates because they may be produced with relative ease and be tailored to have specific mechanical properties, alleviating the stress shielding problem. Long carbon fiber-reinforced polyetheretherketone (LCF PEEK) plates were produced using the extrusion / compression molding process. Static flexural testing determined that LCF PEEK plates with rectangular cross-section had an average flexural modulus of 12 GPa, or 23% of the flexural modulus of a stainless steel plate. The LCF PEEK plates also experienced negligible (14.7%, 14.5%, and 16.7%) reductions in modulus after fatigue testing at applied moments of 2.5, 3.0, and 3.5 N•m, respectively, over 106 load cycles. Aging the plates in 0.9% NaCl solution for four and eight weeks caused 0.34% and 0.28% increases in plate mass, respectively. No significant decrease of flexural properties due to aging was detected. Differential scanning calorimetry (DSC) revealed the PEEK matrix of the plates to be 24.5% crystalline, which is lower than typical PEEK crystallinity values of 30-35%. Scanning electron microscopy (SEM) revealed three times as many fiber pullout areas in LCF PEEK fracture surfaces as in fracture surfaces of long carbon fiber-reinforced polyphenylenesulfide (LCF PPS), another plate material tested. DSC and SEM data suggest that improvements in processing conditions and fiber/matrix bonding, along with higher carbon fiber fractions, would enhance LCF PEEK plate performance. LCF PEEK remains a promising alternative to stainless steel for internal fixation plates.

Warren, Paul B.

88

Plate fixation of fresh displaced midshaft clavicle fractures  

Microsoft Academic Search

From 1992–1994, we operated on 251 fresh completely displaced mid-third clavicle fractures in adults; 232 were followed up. The fractures were plated with a Mizuho C-type plate or an AO\\/ASIF 3.5 mm reconstruction plate. Comminuted fragments were reduced and wired (133 cases). There were 150 men and 82 women; the median age was 37.3 years (range 18–79). The mean follow-up was

Wun-Jer Shen; Tsung-Jen Liu; Young-Shung Shen

1999-01-01

89

Application of lamina replantation with ARCH plate fixation in thoracic and lumbar intraspinal tumors  

PubMed Central

The aim of the present study was to investigate the clinical effects of lamina replantation with ARCH plate fixation on patients with thoracic and lumbar intraspinal tumors, following laminectomy. Thirteen patients with thoracic and lumbar intraspinal tumors underwent total lamina replantation with ARCH plate fixation and repair of the supraspinous ligaments, following laminectomy and tumor enucleation. To investigate the clinical effect of lamina replantation with ARCH plate fixation, pre- and postoperative visual analog scale (VAS), and Oswestry Disability Index (ODI) scores were determined, and pre- and postoperative X-ray and magnetic resonance imaging (MRI) examinations were conducted. Computed tomography (CT) examinations were also included in the follow-up. No complications were observed pre- or postoperatively. The VAS and ODI results 2 weeks following surgery and at the final follow-up examination demonstrated a significant improvement compared with the corresponding preoperative results. The X-ray examination results indicated a satisfactory internal fixation location, without any characteristics of a fracture, lumbar scoliosis, kyphosis or instability. Following the surgery, the CT and MRI examination results demonstrated that healing of the lamina bone and repair of the supraspinous ligament had occurred without tumor recurrence or spinal epidural scar recompression. Two of the 13 cases were lost to follow-up. The results indicated that in patients with thoracic and lumbar intraspinal tumors, lamina replantation with ARCH plate fixation following total laminectomy is effective and provides thoracolumbar stability. Furthermore, this has been identified to be an effective technique for preventing intraspinal scar proliferation.

ZHOU, DONG; NONG, LU-MING; GAO, GONG-MIN; JIANG, YU-QIN; XU, NAN-WEI

2013-01-01

90

Radiographic Comparison of Four Anterior Fusion Methods in Two Level Cervical Disc Diseases : Autograft Plate Fixation versus Cage Plate Fixation versus Stand-Alone Cage Fusion versus Corpectomy and Plate Fixation  

PubMed Central

Objective To evaluate radiographic results of anterior fusion methods in two-level cervical disc disease : tricortical autograft and plate fixation (ACDF-AP), cage and plate fixation (ACDF-CP), stand-alone cage (ACDF-CA), and corpectomy and plate fixation (ACCF). Methods The numbers of patients were 70 with a minimum 6 month follow-up (ACDF-AP : 12, ACDF-CP : 27, ACDF-CA : 15, and ACCF : 16). Dynamic simple X-ray and computed tomography were evaluated preoperatively, postoperatively, 6 month, and at the final follow-up. The fusion and subsidence rates at the final were determined, and global cervical lordosis (GCL), cervical range of motion, fused segment angle (FSA), and fused segment height (FSH) were analyzed. Results Nonunion was observed in 4 (25%) patients with ACDF-CA, 1 (8%) patient with ACDF-AP, 1 (4%) patient with ACDF-CP. The number of loss of FSH (%) more than 3 mm were 2 patients (16%) in ACDF-AP, 3 patients (11%) in ACDF-CP, 5 patients (33%) in ACDF-CA, and 3 patients (20%) in ACCF. The GCL was decreased with ACDF-CA and increased with others. The FSA was increased with ACDF-AP, ACDF-CP, and ACCF, but ACDF-CA was decreased. At the final follow-up, the FSH was slightly decreased in ACDF-CP, ACDF-AP, and ACCF, but ACDF-CA was more decreased. Graft related complication were minimal. Screw loosening, plate fracture, cage subsidence and migration were not identified. Conclusion ACDF-CP demonstrated a higher fusion rate and less minimal FSH loss than the other fusions in two-level cervical disc disease. The ACDF-AP and ACCF methods had a better outcome than the ACDF-CA with respect to GCL, FSA, and FSH.

Kim, Min-Ki; Jeon, Kwang-Mo; Kim, Tae-Sung

2012-01-01

91

Does smoking have an impact on fusion rate in single-level anterior cervical discectomy and fusion with allograft and rigid plate fixation?  

PubMed

Object Although smoking has been shown to negatively affect fusion rates in patients undergoing multilevel fusions of the cervical and lumbar spine, the effect of smoking on fusion rates in patients undergoing single-level anterior cervical discectomy and fusion (ACDF) with allograft and plate fixation has yet to be thoroughly investigated. The objective of the present study was to address the effect of smoking on fusion rates in patients undergoing a 1-level ACDF with allograft and a locked anterior cervical plate. Methods This study is composed of patients from the control groups of 5 separate studies evaluating the use of an anterior cervical disc replacement to treat cervical radiculopathy. For each of the 5 studies the control group consisted of patients who underwent a 1-level ACDF with allograft and a locked cervical plate. The authors of the present study reviewed data obtained in a total of 573 patients; 156 patients were smokers and 417 were nonsmokers. A minimum follow-up period of 24 months was required for inclusion in this study. Fusion status was assessed by independent observers using lateral, neutral, and flexion/extension radiographs. Results An overall fusion rate of 91.4% was achieved in all 573 patients. A solid fusion was shown in 382 patients (91.6%) who were nonsmokers. Among patients who were smokers, 142 (91.0%) had radiographic evidence of a solid fusion. A 2-tailed Fisher exact test revealed a p value of 0.867, indicating no difference in the union rates between smokers and nonsmokers. Conclusions The authors found no statistically significant difference in fusion status between smokers and nonsmokers who underwent a single-level ACDF with allograft and a locked anterior cervical plate. Although the authors do not promote tobacco use, it appears that the use of allograft with a locked cervical plate in single-level ACDF among smokers produces similar fusion rates as it does in their nonsmoking counterparts. PMID:23992432

Luszczyk, Myles; Smith, Justin S; Fischgrund, Jeffrey S; Ludwig, Steven C; Sasso, Rick C; Shaffrey, Christopher I; Vaccaro, Alexander R

2013-08-30

92

Are there any differences in various polyaxial locking systems? A mechanical study of different locking screws in multidirectional angular stable distal radius plates.  

PubMed

Numerous angular stable plates for the distal radius exist, and technically based comparisons of the polyaxial locking interfaces are lacking. The aim of this mechanical study was to investigate three different locking interfaces of angular stable volar plates by cantilever bending: VA-LCP Two-Column Distal Radius Plates 2.4 mm (Synthes® GmbH, Oberdorf, Switzerland), IXOS® P4 (Martin, Tuttlingen, Germany) and VariAX™ (Stryker®, Duisburg, Germany). We assessed the strength of 0°, 5°, 10° and 15° screw locking angles and tested the bending strength from 10° to 5° angles by cyclic loading until breakage. The final setup repeated the above assessments by inclusion of four locking screws. The single screw-plate interfaces of the VA-LCP showed the highest bending moment at an angle of 0° and 5°, the IXOS® P4 at an angle of 10° and 15° and the VariAX™ when changing the insertion angle from 10° into 5°. The strength of polyaxial locking interfaces and mechanism of failure proved to be different among the examined plates. PMID:23449519

Mehling, Isabella; Scheifl, Rebekka; Mehler, Dorothea; Klitscher, Daniela; Hely, Hans; Rommens, Pol M

2013-04-01

93

The biomechanical analysis of three plating fixation systems for periprosthetic femoral fracture near the tip of a total hip arthroplasty  

Microsoft Academic Search

BACKGROUND: A variety of techniques are available for fixation of femoral shaft fractures following total hip arthroplasty. The optimal surgical repair method still remains a point of controversy in the literature. However, few studies have quantified the performance of such repair constructs. This study biomechanically examined 3 different screw-plate and cable-plate systems for fixation of periprosthetic femoral fractures near the

James P Lever; Rad Zdero; Markku T Nousiainen; James P Waddell; Emil H Schemitsch

2010-01-01

94

Lateral fixation of open AO type-B2 ankle fractures: the Knowles pin versus plate  

Microsoft Academic Search

Forty-seven patients with open lateral malleolar (AO type-B2) fractures treated with copious irrigation and radical debridement,\\u000a reduction, and immediate fixation by Knowles pins or lateral plates were retrospectively reviewed with an average follow-up\\u000a period of 29 months. The 47 patients were divided into two groups, based on the method of treatment. The Knowles pin group\\u000a included 25 patients. The plate group

Yih-Shiunn Lee; Shu-Wen Chen

2009-01-01

95

Locking Compression Plate and Cerclage Band for Type B1 Periprosthetic Femoral Fractures  

Microsoft Academic Search

We present results of 12 type B1 periprosthetic femoral fractures treated with locking compression plate and cerclage band from January 2003 to June 2007. The average follow-up was 30.1 months. Twelve fractures united in an average period of 4.8 months. The mean Harris hip score was 84.4. One patient presented with loosening of proximal screws at 5 months. This patient

Huaming Xue; Yihui Tu; Minwei Cai; Anli Yang

2011-01-01

96

A preliminary study of bending stiffness alteration in shape changing nitinol plates for fracture fixation.  

PubMed

Nitinol is a promising biomaterial based on its remarkable shape changing capacity, biocompatibility, and resilient mechanical properties. Until now, very limited applications have been tested for the use of Nitinol plates for fracture fixation in orthopaedics. Newly designed fracture-fixation plates are tested by four-point bending to examine a change in equivalent bending stiffness before and after shape transformation. The goal of stiffness alterable bone plates is to optimize the healing process during osteosynthesis in situ that is customized in time of onset, percent change as well as being performed non-invasively for the patient. The equivalent bending stiffness in plates of varying thicknesses changed before and after shape transformation in the range of 24-73% (p values <0.05 for all tests). Tests on a Nitinol plate of 3.0 mm increased in stiffness from 0.81 to 0.98 Nm² (corresponding standard deviation 0.08 and 0.05) and shared a good correlation to results from numerical calculation. The stiffness of the tested fracture-fixation plates can be altered in a consistent matter that would be predicted by determining the change of the cross-sectional area moment of inertia. PMID:21286815

Olender, Gavin; Pfeifer, Ronny; Müller, Christian W; Gösling, Thomas; Barcikowski, Stephan; Hurschler, Christof

2011-02-01

97

Two potential causes of EPL rupture after distal radius volar plate fixation.  

PubMed

Rupture of the extensor pollicis longus tendon can occur after volar plate fixation of dorsally comminuted distal radius fractures. We attempted to identify the etiology of extensor pollicis longus tendon injury after volar plate fixation of the distal radius and potential solutions to this problem. After describing two case reports, we examine six cadaveric specimens and retrospectively review 10 selected patients to evaluate possible technique refinements to minimize damage to the extensor pollicis longus tendon during volar plating of the distal radius. We identify specific screw holes in three commercially available volar distal radius plates that direct the drill bit or prominent screw tips into the third extensor compartment. In addition, after reduction and plate fixation, bone fragments or dorsal gapping may predispose the extensor pollicis longus tendon to injury. We recommend either using shorter screw lengths or leaving the implicated plate holes unfilled. In addition, we suggest consideration of an open assessment of the third extensor compartment, if indicated, as performed through a small dorsal incision ulnar to Lister's tubercle. PMID:16770281

Benson, Eric C; DeCarvalho, Alex; Mikola, Elizabeth A; Veitch, John M; Moneim, Moheb S

2006-10-01

98

Biomechanics of bone-fracture fixation by stiffness-graded plates in comparison with stainless-steel plates  

PubMed Central

Background In the internal fixation of fractured bone by means of bone-plates fastened to the bone on its tensile surface, an on-going concern has been the excessive stress-shielding of the bone by the excessively-stiff stainless-steel plate. The compressive stress-shielding at the fracture-interface immediately after fracture-fixation delays callus formation and bone healing. Likewise, the tensile stress-shielding of the layer of the bone underneath the plate can cause osteoporosis and decrease in tensile strength of this layer. Method In order to address this problem, we propose to use stiffness-graded plates. Accordingly, we have computed (by finite-element analysis) the stress distribution in the fractured bone fixed by composite plates, whose stiffness is graded both longitudinally and transversely. Results It can be seen that the stiffness-graded composite-plates cause less stress-shielding (as an example: at 50% of the healing stage, stress at the fracture interface is compressive in nature i.e. 0.002 GPa for stainless steel plate whereas stiffness graded plates provides tensile stress of 0.002 GPa. This means that stiffness graded plate is allowing the 50% healed bone to participate in loadings). Stiffness-graded plates are more flexible, and hence permit more bending of the fractured bone. This results in higher compressive stresses induced at the fractured faces accelerate bone-healing. On the other hand, away from the fracture interface the reduced stiffness and elastic modulus of the plate causes the neutral axis of the composite structure to be lowered into the bone resulting in the higher tensile stress in the bone-layer underneath the plate, wherein is conducive to the bone preserving its tensile strength. Conclusion Stiffness graded plates (with in-built variable stiffness) are deemed to offer less stress-shielding to the bone, providing higher compressive stress at the fractured interface (to induce accelerated healing) as well as higher tensile stress in the intact portion of the bone (to prevent bone remodeling and osteoporosis).

Ganesh, VK; Ramakrishna, K; Ghista, Dhanjoo N

2005-01-01

99

Corrective Osteotomy for Deformity of the Distal Radius Using a Volar Locking Plate  

PubMed Central

Dorsally angulated malunions of the distal radius have historically been corrected with an opening wedge osteotomy fixed with a dorsal plate. Volar locking plates may facilitate a less morbid approach to corrective osteotomies of the wrist. Eight consecutive patients with an average age of 40 years (range, 15–52 years) underwent correction of a distal radius deformity through a volar approach. Clinical follow-up averaged 17.4 months (range, 7–41 months). Preoperative radiographs revealed an average of 24° of dorsal tilt in patients with dorsal deformity. Postoperatively, their average measurement was <3° of volar tilt. Patients were initially ulnar-positive with an average of 4 mm ulnar-positive variance (range, 2–7 mm). This corrected to less than 1 mm postoperatively. Postoperative disabilities of the arm, shoulder, and hand (DASH), SF-12, and Mayo Wrist scores averaged 10.8, 40.5, and 82.5, respectively. There were no nonunions, and no plates required removal. Distal radius deformity can be effectively addressed through a volar approach with the use of a locking plate.

Peterson, Brett; Gajendran, Varun

2007-01-01

100

A comparison of parallel and diverging screw angles in the stability of locked plate constructs.  

PubMed

We investigated the static and cyclical strength of parallel and angulated locking plate screws using rigid polyurethane foam (0.32 g/cm(3)) and bovine cancellous bone blocks. Custom-made stainless steel plates with two conically threaded screw holes with different angulations (parallel, 10° and 20° divergent) and 5 mm self-tapping locking screws underwent pull-out and cyclical pull and bending tests. The bovine cancellous blocks were only subjected to static pull-out testing. We also performed finite element analysis for the static pull-out test of the parallel and 20° configurations. In both the foam model and the bovine cancellous bone we found the significantly highest pull-out force for the parallel constructs. In the finite element analysis there was a 47% more damage in the 20° divergent constructs than in the parallel configuration. Under cyclical loading, the mean number of cycles to failure was significantly higher for the parallel group, followed by the 10° and 20° divergent configurations. In our laboratory setting we clearly showed the biomechanical disadvantage of a diverging locking screw angle under static and cyclical loading. PMID:21911539

Wähnert, D; Windolf, M; Brianza, S; Rothstock, S; Radtke, R; Brighenti, V; Schwieger, K

2011-09-01

101

Biomechanical comparison of axial load between cannulated locking screws and noncannulated cortical locking screws.  

PubMed

The goal of this study was to compare the biomechanical stability of cannulated locking screws and noncannulated cortical locking screws in a periarticular locking plate. Twelve fresh-frozen porcine tibias with a 1-cm gap created distal to the tibial plateau were used to simulate an unstable proximal tibial fracture. All specimens were fixed with a periarticular proximal lateral tibial locking plate and divided into 2 groups based on whether the proximal metaphyseal screw holes of the plate were inserted with either cannulated locking screws or noncannulated cortical locking screws. An axial compressive load was applied to cause failure in each specimen using a materials testing instrument. The axial stiffness and maximum failure strength in axial loading were recorded. Axial stiffness of the constructs using noncannulated cortical locking screw was significantly higher than that of the constructs using cannulated locking screws (P=.006). Axial failure strength of the constructs using noncannulated cortical locking screw was significantly higher than that of the constructs using cannulated locking screws (P=.002). The failure mode observed in all specimens was a permanent screw-bending deformity over the head-shaft junction of proximal metaphyseal screws, irrespective of whether they were cannulated or noncannulated cortical locking screws. Fixation with noncannulated cortical locking screws offered more stability than cannulated locking screws with regard to axial stiffness and failure strength in a porcine model with unstable proximal tibial fractures. PMID:24093710

Yang, Shan-Wei; Kuo, Shyh Ming; Chang, Shwu Jen; Su, Tian-Shiang; Chen, Hsiang-Ho; Renn, Jenn-Huei; Lin, Ting-Sheng

2013-10-01

102

Work in progress report - Cardiac general Sternal closure with titanium plate fixation - a paradigm shift in preventing mediastinitis  

Microsoft Academic Search

Sternal instability predisposes to post-operative mediastinitis. Biomechanical studies have shown the superiority of rigid plate fixation over wire circlage in sternal healing. We studied rigid plate fixation for sternotomies in high-risk patients. High-risk patients were identified as those having three or more historically established risk factors for post-operative mediastinitis, such as COPD, re-operative surgery, renal failure, diabetes, steroid use, obesity,

Jai Raman; David H. Song; Gil Bolotin; Valluvan Jeevanandam

2010-01-01

103

Treatment of type 2 and 4 olecranon fractures with locking compression plate osteosynthesis in horses: a prospective study (2002-2008).  

PubMed

This prospective study describes a series of 18 olecranon fractures in 16 horses that were treated with locking compression plates (LCP). Twelve of the 18 fractures were simple (type 2), whereas six were comminuted (type 4). Six fractures were open and 12 were closed. Each horse underwent LCP osteosynthesis consisting of open reduction and application of one or two LCP. Complete fracture healing was achieved in 13 horses. Three horses had to be euthanatized: two because of severe infection and one because of a comminuted radial fracture 11 days after fixation of the olecranon fracture. Complications encountered after discharge of the horses from the Equine Hospital at the Vetsuisse Faculty (University of Zurich) included implant infection (n=2) and lameness (n=3), which were successfully treated with implant removal. Despite being easier to use, LCP osteosynthesis resulted in a clinical outcome similar to DCP osteosynthesis. PMID:21103649

Jackson, M; Kummer, M; Auer, J; Hagen, R; Fuerst, A

2010-11-19

104

LCP external fixation - External application of an internal fixator: two cases and a review of the literature  

PubMed Central

The locking compression plate (LCP) is an angle-stable fixator intended for intracorporeal application. In selected cases, it can be applied externally in an extracorporeal location to function as a monolateral external fixator. We describe one patient with Schatzker V tibial plateau fracture and one patient with Gustillo IIIB open tibia shaft fracture treated initially with traditional external fixation for whom exchange fixation with externally applied LCPs was performed. The first case went on to bony union while the second case required bone grafting for delayed union. Both patients found that the LCP external fixators facilitated mobilization and were more manageable and aesthetically acceptable than traditional bar-Schanz pin fixators.

2010-01-01

105

Plate fixation of comminuted olecranon fractures: an in vitro biomechanical study.  

PubMed

The stiffness, cyclic stability, and failure strength of posterior and lateral plating were compared in an in vitro model of a comminuted olecranon fracture. Loading was applied to the brachialis and triceps while displacements of the olecranon were measured with an electromagnetic tracking device in six degrees of freedom. No statistical difference was seen in the cyclic or static stability of either plating method. The triceps tendon suture attachment failed during destructive testing in each case between 300 and 500 N of applied loading. No gross failure of the bony fixation of the implant occurred before suture failure. These results suggest that both plating methods are likely to afford adequate stability to permit early protected postoperative range of motion. PMID:8981268

King, G J; Lammens, P N; Milne, A D; Roth, J H; Johnson, J A

106

Anterior cervical interbody fusion with plate fixation for chronic spondylotic radiculopathy: a 2- to 8-year follow-up.  

PubMed

In retrospectively analyzing 35 consecutive patients with chronic spondylotic radiculopathy treated by nerve root decompression, interbody fusion (Robinson technique), and plating, we studied the perioperative complication rate as well as the long-term clinical and radiologic outcomes of an additional plate fixation in degenerative cervical disorders. After an average of 54 months (range 24-102 months), all cases were reviewed for the purpose of this study. There were no perioperative or postoperative complications related to the plate fixation. In particular, there was no infection, graft extrusion, or neurologic deterioration. A solid fusion was obtained in all cases with a single-level fusion and in 87% of the cases with a multilevel fusion. The overall fusion rate was 94%. The clinical outcome of the patients with chronic radiculopathy was comparable with that in the literature, with only three patients (8.6%) having a poor result. This study demonstrated that plate fixation can be a useful adjunct in patients undergoing interbody fusion for cervical spondylotic radiculopathy. Plate fixation seems to reduce the rate of nonunion without additional hazards for the patient. This report should form the basis for a prospective randomized trial to answer the question more conclusively of whether an additional plate fixation is superior to uninstrumented cervical fusion in degenerative disorders. PMID:10382774

Schneeberger, A G; Boos, N; Schwarzenbach, O; Aebi, M

1999-06-01

107

A comparative study of blade plate fixation and external fixation in osteotomies for slipped capital femoral epiphysis.  

PubMed

We have performed corrective osteotomies for moderate or severe slipped capital femoral epiphysis (SCFE) using an original blade plate (BP) until 2006 and using a hybrid external fixator (EF) since 2007. We designed a comparative study of the short-term results between BP and EF devices in the treatment of proximal femoral osteotomies in SCFE. Nineteen SCFE patients (12 BP; seven EF) who underwent corrective osteotomies at our institution were included. Clinical and radiographic valuables including the operative time, intraoperative blood loss, postoperative improvement of head shaft angle, and posterior tilting angle, Harris hip score, limb-length discrepancy, and associated complications were compared between the two groups. Although there were no significant differences between the two groups in postoperative improvement of head shaft angle and posterior tilting angle, Harris hip score, and limb-length discrepancy, the EF group showed significantly shorter operative time and less intraoperative blood loss. Serious complications were observed in two patients of the BP group (deep infection and chondrolysis, respectively) and one of the EF group (chondrolysis). Percutaneous proximal femoral osteotomy using an EF appears to be safe, easy, and effective in correcting multiplanar deformities associated with SCFE. It has potential advantages over commonly used open techniques in terms of simplicity and less invasiveness. PMID:23797857

Kitoh, Hiroshi; Kitakoji, Takahiko; Hattori, Tadashi; Kaneko, Hiroshi; Mishima, Kenichi; Matsushita, Masaki; Ishiguro, Naoki

2013-11-01

108

Achieving locked intramedullary fixation of long bone fractures: technology for the developing world.  

PubMed

Eighty per cent of severe fractures occur in developing countries. Long bone fractures are treated by conservative methods if proper implants, intraoperative imaging and consistent electricity are lacking. These conservative treatments often result in lifelong disability. Locked intramedullary nailing is the standard of care for long bone fractures in the developed world. The Surgical Implant Generation Network (SIGN) has developed technology that allows all orthopaedic surgeons to treat fracture patients with locked intramedullary nailing without the need for image intensifiers, fracture tables or power reaming. Introduced in 1999, SIGN nails have been used to treat more than 100,000 patients in over 55 developing world countries. SIGN instruments and implants are donated to hospitals with the stipulation that they will be used to treat the poor at no cost. Studies have shown that patients return to function more rapidly, hospital stays are reduced, infection rates are low and clinical outcomes excellent. Cost-effectiveness analysis has confirmed that the system not only provides better outcomes, but does so at a reduced cost. SIGN continues to develop new technologies, in an effort to transform lives and bring equality in fracture care to the poorest of regions. PMID:22847118

Phillips, Jonathan; Zirkle, Lewis G; Gosselin, Richard A

2012-07-31

109

Internal fixation of traumatic diastasis of pubic symphysis: is plate removal essential?  

Microsoft Academic Search

Introduction  Internal fixation of the traumatic diastasis of symphysis pubis is an integral part of the definitive management of pelvic\\u000a ring injuries. Both functional outcome and long term physiological effects of plate retention have not been clearly addressed\\u000a and no specific indications regarding implant removal have been proposed in the literature.\\u000a \\u000a \\u000a \\u000a Materials and methods  We reviewed 74 patients (18 females and 56

Peter V. Giannoudis; Byron E. Chalidis; Craig S. Roberts

2008-01-01

110

A comparison of plate versus staple-and-cast fixation in maintaining femoral tibial alignment after valgus tibial osteotomy  

PubMed Central

Purpose To compare 2 methods of fixation for maintenance of alignment during healing of valgus tibial osteotomies. Methods We performed a retrospective chart and radiographic review of valgus tibial osteotomy cases of staple fixation supplemented by a postoperative cast and of blade plate fixation for maintenance of femoral–tibial alignment during healing of the osteotomy. Results Both groups (staple-and-cast, n = 16; plate, n = 28) were similar in terms of age, preoperative alignment, extent of osteoarthritis and degree of intra-operative correction. Between-group differences in the maintenance of femoral–tibial alignment during healing were not significant. In both groups there was a strong correlation between degree of bone contact at the osteotomy site and maintenance of alignment (p < 0.005). In cases done with the plate, 90% of osteotomies with good or excellent bone contact maintained alignment during healing; with poor or fair bone contact, 75% had loss of alignment > 5° during healing. There was a trend toward a greater incidence of delayed or non-union with plate fixation compared with staple fixation that did not reach statistical significance. All of these cases of delayed/non-union had loss of femoral–tibial alignment > 5° during healing. Conclusion As a result of this study, we have modified our surgical technique. We now use intra-operative fluoroscopy for optimizaiton of bone contact, and we have reverted to the less invasive staple method for fixation of tibial osteotomies.

Harrison, Mark M.; Waddell, James P.

2005-01-01

111

Locking Compression Plates for the Treatment of Periprosthetic Femoral Fractures Around Well-Fixed Total Hip and Knee Implants  

Microsoft Academic Search

There are currently few published studies examining the use of locking compression plates for the treatment of periprosthetic femoral fractures. Fifteen total hip or knee arthroplasty patients with 16 Vancouver type B1 and C fractures with an average age of 76 years were fixed and followed clinically and radiographically for 2 years. Fourteen patients achieved radiographic union by 6 months,

Gavin C. A. Wood; Doug R. Naudie; James McAuley; Richard W. McCalden

2011-01-01

112

A video guided solution for screw insertion in orthopedic plate fixation  

NASA Astrophysics Data System (ADS)

In orthopedic and trauma surgery, metallic plates are used for reduction and fixation of bone fractures. In clinical practice, the intra-operative planning for screw fixation is usually based on fluoroscopic images. Screw fixation is then performed on a free-hand basis. As such, multiple attempts may be required in order to achieve an optimal positioning of the fixing screws. To help the physician insert the screws in accordance to the planned position, we propose a method for screw insertion guidance. Our approach uses a small video camera, rigidly placed on the drill, and a set of small markers that are rigidly fixed on a variable angle drill sleeve. In order to investigate the achievable accuracy of our setup, we simulate the estimation of the drill bit position under two different marker arrangements, planar and 3D, and different noise levels. Furthermore, we motivate our choices for marker design and position given the limited space available for marker positioning, the requirement for accurate position estimation of the drill bit and the illumination changes that could affect the surgical site. We also describe our proposed marker detection and tracking pipeline. Our simulation results let us conclude that we can achieve an accuracy of 1° and 1mm in the estimation of angular orientation and tip position of the drill bit respectively, provided that we have accurate marker detection.

Magaraggia, J.; Kleinszig, G.; Graumann, R.; Angelopoulou, E.; Hornegger, J.

2013-03-01

113

A shear-locking free robust isoparametric three-node triangular finite element for moderately-thick and thin arbitrarily laminated plates  

Microsoft Academic Search

A shear-locking free robust isoparametric three-node triangular finite element is developed for advanced fiber-reinforced arbitrarily laminated moderately-thick and thin plates. The strain-displacement relations are based on Reissner and Mindlin plate theory that accounts for transverse shear deformations into the plate formulation. A shear correction term is introduced into the finite element formulation to circumvent the shear locking effect. Numerical results,

H. R. H. Kabir

1995-01-01

114

Proximal humeral fractures: internal fixation.  

PubMed

Fractures of the proximal humerus are common injuries that are increasing in incidence as the population ages. These fractures are often treated nonsurgically; however, surgery is indicated if displacement, concurrent dislocation, or unacceptable alignment is present. Knowledge of the anatomic and physiologic characteristics of the proximal humerus and shoulder joint and familiarity with the available fixation elements will help surgeons make informed and patient-specific decisions regarding treatment. Reduction and internal fixation of proximal humeral fractures has expanding indications in comparison with arthroplasty, in part because of improvements in fixation technology and a better understanding of anatomy and physiology. The outcomes of proximal humeral fractures managed with percutaneous pinning, open reduction and locked-plate fixation, and intramedullary fixation are being actively investigated. PMID:23395021

Aaron, Daniel; Shatsky, Joshua; Paredes, Juan Carlos S; Jiang, Chunyan; Parsons, Bradford O; Flatow, Evan L

2013-01-01

115

Biomechanical analysis of the acetabular buttress-plate: are complex acetabular fractures in the quadrilateral area stable after treatment with anterior construct plate-1/3 tube buttress plate fixation?  

PubMed Central

OBJECTIVE: The acetabular buttress-plate has been widely used in treating difficult cases with satisfying clinical results. However, the biomechanical properties of a postoperative acetabular fracture fixed by the buttress-plate are not clear. The purpose of this study was to evaluate the biomechanical properties of stability after the anterior tube buttress-plate fixation of complex acetabular fractures in the quadrilateral area. METHODS: A construct was proposed based on anterior construct plate - 1/3 tube buttress plate fixation for acetabular both-column fractures. Two groups of six formalin-preserved cadaveric pelvises were analyzed: (1) group A, the normal pelvis and (2) group B, anterior construct plate-1/3 tube buttress plate with quadrilateral area fixation. The displacements were measured, and cyclical loads were applied in both standing and sitting simulations. RESULTS: As the load was added, the displacements were Aplate - 1/3 tube buttress plate fixation provided a better stable construct for early sitting. The standing mode yielded more significant differences between the groups. Placing a 1/3 tube buttress-plate via an anterior approach is a novel method of providing quadrilateral area support in this setting.

Wu, Yong-De; Cai, Xian-Hua; Liu, Xi-Ming; Zhang, Hong-Xi

2013-01-01

116

New techniques and alternative fixation for the lapidus arthrodesis.  

PubMed

Arthrodesis of the first metatarsocuneiform joint is a powerful and durable procedure to help correct moderate to severe hallux valgus and/or first ray hypermobility. However, painful nonunion remains a notoriously high potential outcome. Research regarding locking plates seems promising, and data show lower rates of nonunion. Innovative fixation techniques are new and should be considered in the future as further literature is available on their long-term use. Regardless of the fixation, proper joint preparation and good compression is fundamentally the most important. A case of Lapidus fusion with locking plates after a failed arthrodesis with screws alone is presented. PMID:23827494

Young, Nathan J; Zelen, Charles M

2013-07-01

117

Use of a 1.5 mm butterfly locking plate for stabilization of atlantoaxial pathology in three toy breed dogs.  

PubMed

The objective of this study was to describe the use of a titanium 1.5 mm locking plate in the stabilization of atlantoaxial pathology in three toy breed dogs. Two dogs with atlantoaxial subluxation and another dog with an axial fracture, confirmed by diagnostic imaging, were stabilized via a ventral approach with a 1.5 mm titanium 5-hole locking butterfly-plate. Surgical reduction and stabilization were assessed by computed tomography and radiography after surgery. Follow-up evaluation for resolution of neurological signs and possible complications was performed in all three dogs. For long-term assessment, a telephone follow-up was performed. A considerable improvement of neurological signs occurred within two to four weeks after surgery. An excellent clinical outcome was identified in all three patients. Adequate stabilization and resolution of neurological signs in all three dogs was achieved. The stabilization of atlantoaxial surgical conditions in toy breeds with the 1.5 mm titanium 5-hole butterfly locking plate appears to be an effective means of surgical treatment. PMID:21327294

Dickomeit, M; Alves, L; Pekarkova, M; Gorgas, D; Forterre, F

2011-02-16

118

A comparative study on four screw-plate locking systems in sheep: a clinical and radiological study.  

PubMed

Four mandibular screw-plate locking systems were studied in sheep. Three to four centimetres angular continuity resections of the mandible were performed and the defects bridged with pre-bent angular reconstruction plates fixed with four screws in the body part and three in the ramus. Each type was used four times. Clinical and radiological examinations were carried out 1 and 2 months later. All sheep were able to eat and ruminate normally throughout the postoperative period. Radiology revealed that 6/16 plates and 5/112 screws fractured during the follow-up period. In one type, no fracture occurred. Screw fracture was confined to just one reconstruction system. Six of 16 mandibles showed slight to moderate bone resorption under the plate. The results point to the internal shortcomings of the systems tested. PMID:11405453

Lindqvist, C; Söderholm, A L; Salo, A; Subasinghe, J; Ylijoki, S; Skutnabb, K; Hallikainen, D

2001-04-01

119

Volar fixation of distal radial fracture using compression plate: clinical and radiographic evaluation of 20 patients.  

PubMed

Distal radius fractures can be treated with different methods, depending on the type of fracture and, on our experience, according to the Fernandez algorithm. The report presents our experience treating distal radius fractures using a volar plate. We reviewed retrospectively 20 patients treated, during a period of 3 years (May 2008-May 2011) at our center, for unstable distal radius fractures using a volar plate. All patients were reviewed by thorough clinical examination and standard radiographs of the operated wrist. For the clinical evaluation, we used Mayo Wrist Score and DASH Score. At review, the injured wrist had recovered an average range of motion in flexion-extension of 120°, and the grip strength was an average of 50% compared to contralateral side. Overall, results at Mayo Wrist Score were good to excellent in 30%, satisfactory in 55%, and poor in 15%; results at DASH Score were good to excellent in 90%, satisfactory in 10% with no poor case. The majority of patients were fully satisfied with the results (65%), 20% of patients were partially satisfied, 5% were poorly satisfied, and 10% were not satisfied. At review, 4 patients reported the presence of transient paresthesia localized to the first three rays of the hand. At radiographic evaluation, the majority of patients had a radial tilt between 20 and 23, ulnar variance between 0 and 3, and dorsal tilt between 9 and 14. The treatment of unstable distal radius fractures with a volar plate provided stable internal fixation and allowed early function and was associated with a low complication rate. PMID:23275031

Giannotti, S; Alfieri, P; Magistrelli, L; Casella, F; Palmeri, L; Guido, G

2012-12-30

120

Fixation of distal radius fractures in adults: a review.  

PubMed

In patients for whom function is a priority, anatomic reduction and stable fixation are prerequisites for good outcomes. Several therapeutic options exist, including orthopedic treatment and internal fixation with pins (intra- and extrafocal), external fixation which may or may not bridge the wrist, and different internal fixation techniques with dorsal or palmar plates using or not, locking screws. Arthroscopy may be necessary in case of articular fracture. In the presence of significant metaphyseal bone defects, filling of the comminution with phosphocalcic cements provides better graft stability. The level of evidence is too low to allow recommending one type of fixation for one type of fracture; and different fixation options to achieve stable reduction exist, each with its own specific complications. With the new generations of palmar plate, secondary displacement is becoming a thing of the past. PMID:23518070

Obert, L; Rey, P-B; Uhring, J; Gasse, N; Rochet, S; Lepage, D; Serre, A; Garbuio, P

2013-03-18

121

Heterogeneous plate locking in the South-Central Chile subduction zone: Building up the next great earthquake  

NASA Astrophysics Data System (ADS)

We use Global Positioning System (GPS) velocities and kinematic Finite Element models (FE-models) to infer the state of locking between the converging Nazca and South America plates in South-Central Chile (36 °S - 46 °S) and to evaluate its spatial and temporal variability. GPS velocities provide information on earthquake-cycle deformation over the last decade in areas affected by the megathrust events of 1960 ( Mw= 9.5) and 2010 ( Mw= 8.8). Our data confirm that a change in surface velocity patterns of these two seismotectonic segments can be related to their different stages in the seismic cycle: Accordingly, the northern (2010) segment was in a final stage of interseismic loading whereas the southern (1960) segment is still in a postseismic stage and undergoes a prolonged viscoelastic mantle relaxation. After correcting the signals for mantle relaxation, the residual GPS velocity pattern suggests that the plate interface accumulates slip deficit in a spatially and presumably temporally variable way towards the next great event. Though some similarity exist between locking and 1960 coseismic slip, extrapolating the current, decadal scale slip deficit accumulation towards the ~ 300-yr recurrence times of giant events here does neither yield the slip distribution nor the moment magnitude of the 1960 earthquake. This suggests that either the locking pattern is evolving in time (to reconcile a slip deficit distribution similar to the 1960 earthquake) or that some asperities are not persistent over multiple events. The accumulated moment deficit since 1960 suggests that highly locked patches in the 1960 segment are already capable of producing a M ~ 8 event if triggered to fail by stress transfer from the 2010 event.

Moreno, M.; Melnick, D.; Rosenau, M.; Bolte, J.; Klotz, J.; Echtler, H.; Baez, J.; Bataille, K.; Chen, J.; Bevis, M.; Hase, H.; Oncken, O.

2011-05-01

122

Microsurgical anterior decompression and internal fixation with iliac bone graft and titanium plates for treatment of cervical intervertebral disc herniation.  

PubMed

42 cervical interbody fusions with iliac bone graft and titanium plate fixation were performed between October 1991 and March 1994. The mean follow up period in this study was 10.7 months. In 32 cases fusion was done for 1 and in 10 cases for 2 segments. 2 different types of plates were used. In 25 cases micro-osteosynthesis plates and screws with 2.7 mm diameter were used, and in 17 cases cervical H-plates and screws with 3.5 mm diameter. A favourable outcome was achieved in 31 of 42 cases (74%). Satisfactory pain relief was achieved in 90%. For radicular motor deficit good results were obtained in 84% and for cervical myelopathy in 54%. The 2 different types of plates showed a remarkable difference in the clinical outcome. The results were regarded favourable in 15 of 25 microplate fusions (60%) and in 16 of 17 H-plate fusions (94%). Compression of the bone graft was seen in 5 patients of the micro plate group, however, radiological signs for fusion were present in all 42 cases at follow up. Major surgical complications, damage to neural structures or neurological deterioration did not occur in this study. Plate fixation in cervical interbody fusions seems to be a safe procedure and may reduce graft related complications at the fusion site if the plates and screws are sufficiently well proportioned. A favourable impact upon the results for cervical interbody fusion might be expected and should be further investigated in a long term follow up study. PMID:8748783

Muhlbauer, M; Saringer, W; Aichholzer, M; Sunder-Plassmann, M

1995-01-01

123

Intraprosthetic fixation techniques in the treatment of periprosthetic fractures-A biomechanical study  

PubMed Central

AIM: To develop new fixation techniques for the treatment of periprosthetic fractures using intraprosthetic screw fixation with inserted threaded liners. METHODS: A Vancouver B1 periprosthetic fracture was simulated in femur prosthesis constructs using sawbones and cemented regular straight hip stems. Fixation was then performed with either unicortical locked-screw plating using the less invasive stabilization system-plate or with intraprosthetic screw fixation using inserted liners. Two experimental groups were formed using either prostheses made of titanium alloy or prostheses made of cobalt chrome alloy. Fixation stability was compared in an axial load-to-failure model. Drilling was performed using a specially invented prosthesis drill with constantly applied internal cooling. RESULTS: The intraprosthetic fixation model with titanium prostheses was superior to the unicortical locked-screw fixation in all tested devices. The intraprosthetic fixation model required 10 456 N ± 1892 N for failure and the unicortical locked-screw plating required 7649 N ± 653 N (P < 0.05). There was no significant difference between the second experimental group and the control group. CONCLUSION: Intraprosthetic screw anchorage with special threaded liners enhances the primary stability in treating periprosthetic fractures by internal fixation.

Brand, Stephan; Klotz, Johannes; Hassel, Thomas; Petri, Maximilian; Haasper, Carl; Bach, Friedrich-Wilhelm; Krettek, Christian; Goesling, Thomas

2012-01-01

124

Prospective blind comparative clinical study of two point fixation of zygomatic complex fracture using wire and mini plates  

PubMed Central

Background The zygomatic maxillary complex (ZMC) fractures are one of the most frequent injuries of the facial skeleton due to its position and facial contour. Assaults, road traffic accidents and falls are the principal etiologic factors that may cause fractures of zygomatic bone. The different fixation methods are applied to treat the zygomatic bone fractures, with many more classifications which have been described in the literature for the ease of management. The type of the fracture, its severity and associated facial fractures usually interferes the treatment modality. Purpose of study The aim of this paper is to show the results of 18yrs prospective blind comparative study using wire and plate osteosynthesis which needed open reduction and internal fixation involving Type II to Type IV Spissel and Schroll ZMC fractures. Materials and methods Total 80 cases included in the study out of 1780 ZMC cases which were treated using wire and plate osteosynthesis over a period of 18 yrs, involving only Type II to Type IV Spissel and Schroll ZMC fractures. Other types excluded from study to prevent observer bias. All the fixations carried out through Standard Dingman's incision using stainless steel 26 gauze wire and titanium 1.5 mm mini plate system under general anesthesia by single maxillofacial surgeon and evaluated by another maxillofacial surgeon who is blinded for surgical procedure after 2 and 4 wks of follow-up for facial symmetry, wound healing, functional assessment (mouth opening, diplopia), and sensory disturbance. All the data tabulated in Excel software (Microsoft) for statistical analysis. P-value calculated to know the Significance of treatment modality in all aspects. Results Result shows no significant p-values indicating both the operating techniques are equally efficient in the surgical management of ZMC fracture. Conclusion Osteosynthesis by mini plates is simple, logical and effective treatment compared to wire osteosynthesis in regard to stability of fracture fragments. Wire osteosynthesis will be helpful in emergency surgeries or where the mini plates are not available. Even though the wire osteosynthesis is economical compared to mini plate fixation; but the time and skill is required for fixation of wires.

2012-01-01

125

The biomechanical analysis of three plating fixation systems for periprosthetic femoral fracture near the tip of a total hip arthroplasty  

PubMed Central

Background A variety of techniques are available for fixation of femoral shaft fractures following total hip arthroplasty. The optimal surgical repair method still remains a point of controversy in the literature. However, few studies have quantified the performance of such repair constructs. This study biomechanically examined 3 different screw-plate and cable-plate systems for fixation of periprosthetic femoral fractures near the tip of a total hip arthroplasty. Methods Twelve pairs of human cadaveric femurs were utilized. Each left femur was prepared for the cemented insertion of the femoral component of a total hip implant. Femoral fractures were created in the femurs and subsequently repaired with Construct A (Zimmer Cable Ready System), Construct B (AO Cable-Plate System), or Construct C (Dall-Miles Cable Grip System). Right femora served as matched intact controls. Axial, torsional, and four-point bending tests were performed to obtain stiffness values. Results All repair systems showed 3.08 to 5.33 times greater axial stiffness over intact control specimens. Four-point normalized bending (0.69 to 0.85) and normalized torsional (0.55 to 0.69) stiffnesses were lower than intact controls for most comparisons. Screw-plates provided either greater or equal stiffness compared to cable-plates in almost all cases. There were no statistical differences between plating systems A, B, or C when compared to each other (p > 0.05). Conclusions Screw-plate systems provide more optimal mechanical stability than cable-plate systems for periprosthetic femur fractures near the tip of a total hip arthroplasty.

2010-01-01

126

Biomechanical analysis of expansion screws and cortical screws used for ventral plate fixation on the cervical spine  

PubMed Central

Compared to bicortical screws, the surgical risk of injuring intraspinal structures can be minimized with the use of monocortical screws. However, this reduction should not be achieved at the expense of the stability of the fixation. With monocortical stabilization, the expansion screws have the potential of absorbing high loads. Therefore, they are expected to be a suitable alternative to bicortical screws for revision surgeries and in osteoporotic bone. The purpose of this in vitro study was to investigate the stiffness of the two screw-plate systems used for ventral stabilization of the cervical spine, by focusing on the suitability of expansion screws as tools for revision treatments. The study was conducted in ten functional units of human cervical spines. The device sample stiffness was determined for four conditions using a turning moment of 2.25 N m each around one of the three principle axes. The conditions were native, destabilized, primarily stabilized with one of the screw-plate systems, followed by secondary stabilization using the expansion screw implant. The stabilized samples achieved a comparable, in most cases higher stiffness than the native samples. The samples undergoing secondary stabilization using expansion screws tend to display greater stiffness for all three axes compared to the primarily stabilized samples. The achieved tightening moment of the screws was higher than the one achieved with primary fixation. Both plates revealed similar primary stability. Revision surgeries with secondary instrumentation achieve a high stiffness of the screwed up segments. Monocortical expansion screws combined with a trapezoidal plate allow ventral stabilization of the cervical spine that is comparable to the plate fixation using bicortical screws.

Ullrich, Bernhard; Huber, Gerd; Morlock, Michael M.

2009-01-01

127

Biomechanical analysis of expansion screws and cortical screws used for ventral plate fixation on the cervical spine.  

PubMed

Compared to bicortical screws, the surgical risk of injuring intraspinal structures can be minimized with the use of monocortical screws. However, this reduction should not be achieved at the expense of the stability of the fixation. With monocortical stabilization, the expansion screws have the potential of absorbing high loads. Therefore, they are expected to be a suitable alternative to bicortical screws for revision surgeries and in osteoporotic bone. The purpose of this in vitro study was to investigate the stiffness of the two screw-plate systems used for ventral stabilization of the cervical spine, by focusing on the suitability of expansion screws as tools for revision treatments. The study was conducted in ten functional units of human cervical spines. The device sample stiffness was determined for four conditions using a turning moment of 2.25 N m each around one of the three principle axes. The conditions were native, destabilized, primarily stabilized with one of the screw-plate systems, followed by secondary stabilization using the expansion screw implant. The stabilized samples achieved a comparable, in most cases higher stiffness than the native samples. The samples undergoing secondary stabilization using expansion screws tend to display greater stiffness for all three axes compared to the primarily stabilized samples. The achieved tightening moment of the screws was higher than the one achieved with primary fixation. Both plates revealed similar primary stability. Revision surgeries with secondary instrumentation achieve a high stiffness of the screwed up segments. Monocortical expansion screws combined with a trapezoidal plate allow ventral stabilization of the cervical spine that is comparable to the plate fixation using bicortical screws. PMID:19588171

Röhl, Klaus; Ullrich, Bernhard; Huber, Gerd; Morlock, Michael M

2009-07-09

128

New Transverse Plate Fixation System for Complicated Sternal Wound Infection After Median Sternotomy  

Microsoft Academic Search

Wire fixation after median sternotomy is a safe proce- dure, but it is still associated with potential wound infection including bony dehiscence. In case of infection and dehiscence the sternum is re-fixated with steel wires. If this is insufficient, then flap reconstruction would be another option. We describe an alternative way for com- plicated sternal closure by using a rigid

Andre Plass; Jürg Grünenfelder; Oliver Reuthebuch; Robert Vachenauer; Jean-Marc Gauer; Gregor Zünd; Michele Genoni

129

Plate fixation of premaxillomaxillary suture and compensatory midfacial growth changes in the rabbit.  

PubMed

It has been suggested that rigid fixation of the developing craniofacial skeleton may lead to altered craniofacial growth. However, recent experimental studies have shown that microplate fixation of slow-growing calvarial sutures resulted in regional growth disturbances but had little effect on overall craniofacial growth. The present study was designed to assess the effects of microplate fixation of the more rapidly growing facial sutures on compensatory midfacial growth in the rabbit. Twenty-two 1.5-week-old rabbits were randomly divided into 2 groups: sham controls (n = 11) and animals with bilateral premaxillomaxillary suture fixation (n = 11). Fixation was accomplished using an intraoral approach, a 6-mm straight Luhr microplate, and two 2-mm long self-tapping screws across each suture. Serial lateral head radiographs were collected at 1.5, 3.5, 6, 12, and 18 weeks of age. Results revealed that by 3.5 weeks, animals with rigid fixation showed significantly shortened premaxillary lengths (p < 0.05), class III occlusal relationships, decreased midfacial heights, and abnormal palatocranial base angles compared with sham control animals. By 12 weeks of age, "catch-up" growth was evident in most dimensions in animals with fixation compared with shams. Gross examination of the cleaned and dried skulls revealed bony bridging across the premaxillomaxillary suture and osseous fracture lines extending superiorly from the site of screw fixation. Results demonstrated that rigid fixation of a rapidly growing facial suture did not impair long-term midfacial growth in the rabbit model and suggest that compensatory changes may have occurred at fracture lines from the self-tapping screws in these animals. PMID:1298421

Mooney, M P; Losken, H W; Siegel, M I; Tsachakaloff, A; Losken, A; Janosky, J

1992-12-01

130

[Fixation of periprosthetic femur fractures with the less invasive stabilization system (LISS)--a new minimally invasive treatment with locked fixed-angle screws].  

PubMed

The Less Invasive Stabilization System (LISS) is a minimally invasive technique indicated for fixation of periprosthetic fractures. This new system allows percutaneous placement of cortical-shaft screws and fixation of the fracture with fixed-angle locked screws with minimal surgical exposure of the mostly osteoporotic bone and without disturbance of the existing total joint replacement. Immediate range-of-motion exercises are begun postoperatively. A retrospective clinical review of 5 patients (2 total hip arthroplasties, 3 total knee arthroplasties) was performed to describe indications, surgical technique, intra- and postoperative complications and patient follow-up. Indications are periprosthetic distal femur fractures, per- and supracondylar fractures. Contraindications are none, except existing medical comorbidities. Extraarticular fractures were treated via stab incisions over the lateral femoral condyle. Fractures with intraarticular displacement were fixed via an anterolateral parapatellar approach to the knee joint. After anatomic reduction of femoral condyles, articular fragments are fixed with Kirschner wires, followed by closed reduction aligning the articular fragments controlling length, axis and rotation. The LISS is introduced proximally under the M. vastus lateralis along the femur. It is fixed with self-drilling cortical shaft screws, locked fixed-angle screws both proximally and distally. Range-of-motion exercises are begun on the second day postoperatively. Time to full weight bearing averaged 6-8 weeks depending on clinical and radiological findings. Benefits of the LISS technique include the minimally invasive approach with increased primary stability using monocortical fixings thus eliminating the need for spongiosaplasty and blood transfusion. Disadvantages of the percutaneous placement of the LISS include malplacement on the femur, proximal screw pull-out and postoperative rotational and axial malalignment. PMID:12594614

Kolb, W; Guhlmann, H; Friedel, R; Nestmann, H

2003-01-01

131

Anterior cervical fusion with interbody cage containing ?-tricalcium phosphate augmented with plate fixation: a prospective randomized study with 2-year follow-up  

PubMed Central

A variety of bone graft substitutes, interbody cages, and anterior plates have been used in cervical interbody fusion, but no controlled study was conducted on the clinical performance of ?-tricalcium phosphate (?-TCP) and the effect of supplemented anterior plate fixation. The objective of this prospective, randomized clinical study was to evaluate the effectiveness of implanting interbody fusion cage containing ?-TCP for the treatment of cervical radiculopathy and/or myelopathy, and the fusion rates and outcomes in patients with or without randomly assigned plate fixation. Sixty-two patients with cervical radiculopathy and/or myelopathy due to soft disc herniation or spondylosis were treated with one- or two-level discectomy and fusion with interbody cages containing ?-TCP. They were randomly assigned to receive supplemented anterior plate (n = 33) or not (n = 29). The patients were followed up for 2 years postoperatively. The radiological and clinical outcomes were assessed during a 2-year follow-up. The results showed that the fusion rate (75.0%) 3 months after surgery in patients treated without anterior cervical plating was significantly lower than that (97.9%) with plate fixation (P < 0.05), but successful bone fusion was achieved in all patients of both groups at 6-month follow-up assessment. Patients treated without anterior plate fixation had 11 of 52 (19.2%) cage subsidence at last follow-up. No difference (P > 0.05) was found regarding improvement in spinal curvature as well as neck and arm pain, and recovery rate of JOA score at all time intervals between the two groups. Based on the findings of this study, interbody fusion cage containing ?-TCP following one- or two-level discectomy proved to be an effective treatment for cervical spondylotic radiculopathy and/or myelopathy. Supplemented anterior plate fixation can promote interbody fusion and prevent cage subsidence but do not improve the 2-year outcome when compared with those treated without anterior plate fixation.

Jiang, Lei-Sheng

2008-01-01

132

Internal fixation of fractures of the shaft of the humerus by dynamic compression plate or intramedullary nail: A prospective study  

PubMed Central

Background: The indications for surgical management of fractures of the shaft of the humerus are clear, but selecting the right implant for internal fixation of humeral fractures has been a dilemma. Materials and Methods: Thirty-six patients (mean age 40.53 years) with fractures of the shaft of the humerus were followed for 12 to 24 months in a prospective study. Eighteen patients each underwent open reduction and internal fixation with compression plating and ante grade interlock nailing. Clinical and radiographic outcome measures included fracture healing, shoulder and elbow functions, need for additional procedures and any complication such as infection and recovery of radial nerve palsy. The results were analyzed statistically using the SPSS 11.5 software, with parametric and nonparametric tests. Results: Nine of the fractures treated with compression plating and seven of those treated with interlock nailing achieved union within six months. Though there was no significant difference in union time between the treatment groups, patients operated with interlock nailing underwent more number of secondary bone grafting procedures to obtain union (six against two). There were 12 patients (66.6%) with excellent and good results in the plating group compared to four patients (25%) in the nailing group. Interlock nailing was associated with significant reduction in shoulder function (P=0.03) and in overall results (P=0.02). Conclusion: Though there was no significant difference between plating or nailing in terms of time to union, compression plating is the preferred method in the majority of fractures of the shaft of the humerus with better preservation of joint function and lesser need for secondary bone grafting for union.

Raghavendra, S; Bhalodiya, Haresh P

2007-01-01

133

Coracoid bone graft osteolysis after Latarjet procedure: A comparison study between two screws standard technique vs mini-plate fixation  

PubMed Central

Aims: One of the reason for Latarjet procedure failure may be coracoid graft osteolysis. In this study, we aimed to understand if a better compression between the coracoid process and the glenoid, using a mini-plate fixation during the Latarjet procedure, could reduce the amount of coracoid graft osteolysis. Materials and Methods: A computed tomography scan analysis of 26 prospectively followed-up patients was conducted after modified Latarjet procedure using mini-plate fixation technique to determine both the location and the amount of coracoid graft osteolysis in them. We then compared our current results with results from that of our previous study without using mini-plate fixation to determine if there is any statistical significant difference in terms of corcacoid bone graft osteolysis between the two surgical techniques. Results: The most relevant osteolysis was represented by the superficial part of the proximal coracoid, whereas the deep part of the proximal coracoid graft is least involved in osteolysis and has best bone healing. The current study showed a significant difference only for the deep part of the distal coracoid with our previous study (P < 0.01). Discussion: To our knowledge, there are no studies in literature that show the causes of coracoid bone graft osteolysis after Latarjet procedure. Conclusion: Our study suggests that there is a significant difference only for the deep part of the distal coracoid in terms of osteolysis. At clinical examination, this difference did not correspond with any clinical findings. Level of Evidence: Level 4. Clinical Relevance: Prospective case series, Treatment study.

Giacomo, Giovanni Di; Costantini, Alberto; de Gasperis, Nicola; De Vita, Andrea; Lin, Bernard K. H.; Francone, Marco; Beccaglia, Mario A. Rojas; Mastantuono, Marco

2013-01-01

134

Salvation for hardware failure of resorbable fixation plates in bilateral mandibular angle fractures.  

PubMed

The resorbable fixation system is used for the treatment of facial bone fractures and has many merits. It does not require a fixture removal procedure and is biologically nontoxic. Also, it does not disturb normal growth in growing children. However, there are also many points to be considered, such as resorption time, foreign body reaction, infection rate, or fixation stability depending on the fracture pattern. Because of these factors, there is still controversy over the use of a resorbable system.We present a case of a patient who experienced malunion after using a resorbable fixation system to treat bilateral mandibular angle fracture, which was recovered by corrective osteotomy and vertical ramus osteotomy in our department. PMID:22801123

Kwon, Yong-Dae; Lee, Deok-Won; Choi, Byung-Joon; Suh, Joon-Ho; Ko, Sujin

2012-07-01

135

Modified biplanar open-wedge high tibial osteotomy with rigid locking plate to treat varus knee  

Microsoft Academic Search

Objective  To introduce and characterize the modified biplanar opening high tibial osteotomy with rigid fixation to treat varus knee\\u000a in young and active patients.\\u000a \\u000a \\u000a \\u000a Methods  Between June 2001 to July 2008, 18 patients with monocompartmental degeneration of the knee combined with a varus malalignment\\u000a of the leg had the modified biplanar opening high tibial osteotomy and the osteotomy was fixed with the

Hai-ning Zhang; Jie Zhang; Cheng-yu Lv; Ping Leng; Ying-zhen Wang; Xiang-da Wang; Chang-yao Wang

2009-01-01

136

Infection after open reduction and internal fixation with dynamic compression plates — Clinical and experimental data  

Microsoft Academic Search

Infection rates for open reduction and internal fixation (ORIF) with the DCP in clinical studies are based on heterogeneous data on general risk factors and do not take into account the direct effect of the implant (material, design, surface, technique). The initial degree of bacterial contamination is generally unknown and the applied definition of the term infection is not mentioned.

St. Arens; M. Hansis; U. Schlege; H. Eijer; G. Printzen; W. J. Ziegler; S. M. Perren

1996-01-01

137

Iterative design and testing of a modular anterior plate for lumbar spine fixation applications.  

PubMed

In this study, a modular anterior lumbar plate is designed and tested in an iterative fashion. The study starts with a basic design that is built by combining same-sized modules; an approach that allow inventory costs to be decreased. The basic design is iteratively improved guided by the results of biomechanical tests performed on each new design. At the end of three iterations of improvements, the design is complete and the plate is of sufficient quality for it to be used in anterior surgical operations. Using these plates creates the advantage of being able to increase the size and slot count during surgical operations, even when some of the modules are already fixed to vertebrae. The designed modular plate is shown to be as safe for use as a rigid plate in terms of its static and fatigue biomechanical performances. PMID:23025169

Demir, Teyfik

2012-09-01

138

Biodegradable internal fixation plates enabled with X-ray visibility by a radiopaque layer of ?-tricalcium phosphate and poly (lactic-co-glycolic acid).  

PubMed

Biodegradable polymer plates can be clinically used as an alternative to metal plates (e.g., titanium) for internal fixation, which, however, are not visible with X-ray imaging, often used for post-operative diagnostics. In this study, therefore, we prepared a biodegradable plate enabled with X-ray visibility by attaching a radiopaque layer on a biodegradable fixation plate in clinical use (Inion, Finland). A radiopaque layer was made of a fine powder of a radiopaque agent, ?-tricalcium phosphate (TCP) and a biodegradable binder material, poly (lactic-co-glycolic acid) (PLGA), which were physically mixed without change in their chemical structure. The radiopacity increased as we increased the layer thicknesses from 0.5 mm to 1.3 mm. Regardless of layer thickness, however, the radiopacity decreased with time both in vitro and in vivo due to decreasing density of TCP in the layer by swelling and degradation of a binder material, PLGA. The in vivo study with rabbits revealed that a discernible image of the radiopaque plate could be obtained by X-ray for up to 21 days, also showing the overall biocompatibility 6 months after implantation. Therefore, we conclude that the radiopaque plate prepared in this work is a promising fixation device enabled with both X-ray visibility and biodegradability. PMID:23165646

Shasteen, Catherine; Kwon, Seok Min; Park, Keun Yung; Jung, Sun Young; Lee, Seung Ho; Park, Chun Gwon; Kim, Myung Hun; Kim, Sukwha; Son, Woo-Chan; Choi, Tae Hyun; Choy, Young Bin

2012-11-16

139

Anterior cervical fusion with interbody cage containing beta-tricalcium phosphate augmented with plate fixation: a prospective randomized study with 2-year follow-up.  

PubMed

A variety of bone graft substitutes, interbody cages, and anterior plates have been used in cervical interbody fusion, but no controlled study was conducted on the clinical performance of beta-tricalcium phosphate (beta-TCP) and the effect of supplemented anterior plate fixation. The objective of this prospective, randomized clinical study was to evaluate the effectiveness of implanting interbody fusion cage containing beta-TCP for the treatment of cervical radiculopathy and/or myelopathy, and the fusion rates and outcomes in patients with or without randomly assigned plate fixation. Sixty-two patients with cervical radiculopathy and/or myelopathy due to soft disc herniation or spondylosis were treated with one- or two-level discectomy and fusion with interbody cages containing beta-TCP. They were randomly assigned to receive supplemented anterior plate (n = 33) or not (n = 29). The patients were followed up for 2 years postoperatively. The radiological and clinical outcomes were assessed during a 2-year follow-up. The results showed that the fusion rate (75.0%) 3 months after surgery in patients treated without anterior cervical plating was significantly lower than that (97.9%) with plate fixation (P < 0.05), but successful bone fusion was achieved in all patients of both groups at 6-month follow-up assessment. Patients treated without anterior plate fixation had 11 of 52 (19.2%) cage subsidence at last follow-up. No difference (P > 0.05) was found regarding improvement in spinal curvature as well as neck and arm pain, and recovery rate of JOA score at all time intervals between the two groups. Based on the findings of this study, interbody fusion cage containing beta-TCP following one- or two-level discectomy proved to be an effective treatment for cervical spondylotic radiculopathy and/or myelopathy. Supplemented anterior plate fixation can promote interbody fusion and prevent cage subsidence but do not improve the 2-year outcome when compared with those treated without anterior plate fixation. PMID:18301927

Dai, Li-Yang; Jiang, Lei-Sheng

2008-02-27

140

Dall–Miles cable and plate fixation for the treatment of peri-prosthetic femoral fractures-analysis of results in 13 cases  

Microsoft Academic Search

We present a retrospective review of 13 patients with periprosthetic femoral fractures treated with the Dall–Miles cable and plate fixation system between 1995 and 1999. Of these, 12 fractures were in relation to hip arthroplasty and one was proximal to the femoral component of a total knee replacement. Mean age at presentation was 77 years (range 66–87) with the male

K. M Venu; R Koka; R Garikipati; Y Shenava; T. S Madhu

2001-01-01

141

The Mennen femoral plate for fixation of periprosthetic femoral fractures following hip arthroplasty  

Microsoft Academic Search

Periprosthetic fractures can be treated by various methods. The Mennen femoral plate used to be a common implant in our region to stabilise periprosthetic femoral fractures following hip arthroplasty.This device has been used in 16 patients in our region from three different centres. The periprosthetic femoral fractures occurred approximately 7 years after the hip arthroplasty procedure. After stabilisation of the

Sashin Ahuja; S Chatterji

2002-01-01

142

[External fixation at the wrist and hand].  

PubMed

Distraction radio-metacarpal external fixation is an excellent technique for the osteosynthesis of distal radius fractures, in particular of comminuted articular fractures. The alternative is the locked palmar plate, a more demanding technique. The published literature does not allow concluding if one method is better than the other. The other main possible indications of external fixation at the wrist are comminuted fractures of the base of the thumb metacarpal, distal radius osteotomies, and wrist arthrodeses. At the hand, external minifixation is an excellent technique of osteosynthesis. Stable bone fixation is obtained, allowing early active mobilization of the fingers. The technique is especially indicated to treat open lesions or to perform lengthening, but we use also external minifixation to treat closed fractures, to perform arthrodesis or to cure non-unions, and to maintain the length of the thumb after trapeziectomy for osteoarthrosis. PMID:22458061

Schuind, F; El Kazzi, W; Cermak, K; Donkerwolcke, M; Burny, F

2011-01-01

143

Autograft versus interbody fusion cage without plate fixation in the cervical spine: a randomized clinical study using radiostereometry  

PubMed Central

A primary object with a fusion cage is avoidance of graft collapse with subsequent subsidence and malalignment of the cervical spine that is observed after bone grafting alone. No randomized studies exist that demonstrate the difference between these two methods in terms of graft subsidence and angulation of the fused segment. The size of the study population was calculated to be 24 patients to reach a significant difference at the 95% CI level. Patients with one-level cervical radiculopathy scheduled for surgery were randomized to anterior discectomy and fusion (ACDF) with autograft or to fusion cage, both without plate fixation. Tantalum markers were inserted in the two adjacent vertebrae at the end of surgery. Radiostereometry was performed immediately postoperatively and at regular intervals for 2 years. Questionnaires were used to evaluate the clinical outcome and an unbiased observer graded the outcome after 2 years. No significant differences were found between the two methods after 2 years in regard of narrowing of the disc space (mean 1.7 and 1.4 mm, respectively) or deformation of the fused segment into flexion (mean 7.7° and 4.6°, respectively). Patients in the cage group had a significantly better clinical outcome. The findings of subsidence and flexion deformation of the fused segment after 2 years seem to be of no clinical importance after one-level cervical disc surgery. However, in multi-level surgery using the same methods, an additive effect of the deformations of the fused segments may affect the clinical outcome.

Zoega, Bjorn; Rosen, Hans

2007-01-01

144

Pitfalls in the application of distal femur plates for fractures.  

PubMed

Despite design features intended to aid the surgeon in restoring proper alignment, malunion and implant-related problems are relatively common after a distal femur fracture treated with plate fixation. This article presents case examples of these problems followed by a discussion of the relevant distal femoral anatomy, design features of modern locked distal femur plating systems, and technical points necessary to avoid malunion and implant-related problems when using these devices. PMID:21857537

Collinge, Cory A; Gardner, Michael J; Crist, Brett D

2011-11-01

145

Mechanical comparison of two types of fixation for ludloff oblique first metatarsal osteotomy.  

PubMed

The Ludloff oblique metatarsal osteotomy is an effective method to correct hallux valgus deformity, although a number of problems have been associated with it, including inherent instability, delayed union, dorsal malunion, and fixation failure. The purpose of the present study was to compare the mechanical characteristics of fixation of the Ludloff osteotomy in 20 identical synthetic bone models, 10 fixated using 2 screws (group I) and 10 fixated using 2 screws augmented with a mini locking plate (group II). Each specimen was loaded to failure, and the mean average load to failure, stiffness, and absorbed energy to failure were compared using unpaired Student's t test. The mean average stiffness of the Ludloff osteotomy fixed with 2 screws (group I) and with the supplementary mini locking plate (group II) was 172.7 ± 31.7 N/mm and 193.3 ± 39 N/mm, respectively (p = .21). The mean average load to failure for groups I and II was 278.4 ± 64.4 N and 356.2 ± 77.9 N, respectively (p = .025). The mean average energy absorbed before failure for groups I and II was 506.7 ± 206.4 Nmm and 769.8 ± 339.4 Nmm, respectively (p = .05). The use of a medially applied supplementary mini locking plate offers a simple and effective method to improve the mechanical stability of the Ludloff oblique osteotomy. PMID:21813302

Tsilikas, Stavros P; Stamatis, Emmanouil D; Kourkoulis, Stavros K; Mitousoudis, Athanasios S; Chatzistergos, Panayiotis E; Papagelopoulos, Panayiotis J

2011-08-02

146

A new radiological method to detect dorsally penetrating screws when using volar locking plates in distal radial fractures. The dorsal horizon view.  

PubMed

Penetration of the dorsal screw when treating distal radius fractures with volar locking plates is an avoidable complication that causes lesions of the extensor tendon in between 2% and 6% of patients. We examined axial fluoroscopic views of the distal end of the radius to observe small amounts of dorsal screw penetration, and determined the ideal angle of inclination of the x-ray beam to the forearm when making this radiological view. Six volar locking plates were inserted at the wrists of cadavers. The actual screw length was measured under direct vision through a dorsal approach to the distal radius. Axial radiographs were performed for different angles of inclination of the forearm at the elbow. Comparing axial radiological measurements and real screw length, a statistically significant correlation could be demonstrated at an angle of inclination between 5° and 20°. The ideal angle of inclination required to minimise the risk of implanting over-long screws in a dorsal horizon radiological view is 15°. PMID:23908427

Haug, L C; Glodny, B; Deml, C; Lutz, M; Attal, R

2013-08-01

147

Open reduction and internal fixation versus casting for highly comminuted and intra-articular fractures of the distal radius (ORCHID): protocol for a randomized clinical multi-center trial  

Microsoft Academic Search

Background  Fractures of the distal radius represent the most common fracture in elderly patients, and often indicate the onset of symptomatic\\u000a osteoporosis. A variety of treatment options is available, including closed reduction and plaster casting, K-wire-stabilization,\\u000a external fixation and open reduction and internal fixation (ORIF) with volar locked plating. The latter is widely promoted\\u000a by clinicians and hardware manufacturers. Closed reduction

Christoph Bartl; Dirk Stengel; Thomas Bruckner; Inga Rossion; Steffen Luntz; Christoph Seiler; Florian Gebhard

2011-01-01

148

Variable fixation of staphylococcal slime by different histochemical fixatives  

Microsoft Academic Search

A variety of histochemical fixatives were used to compare the fixation of bacterial films produced by a standard slime-producing strain ofStaphylococcus epidermidis on plastic tissue culture plates. Some reagents were completely ineffective in fixing the slime layer, whereas others gave variable results. The best alternative to the fixative of the reference method, the potentially explosive Bouin's reagent, was air drying.

L. Baldassarri; W. A. Simpson; G. Donelli; G. D. Christensen

1993-01-01

149

Locking versus nonlocking construct in an osteoporotic, segmental fibula defect model.  

PubMed

Early studies on the treatment of osteoporotic distal fibular fractures suggest that poor bone quality can compromise fixation and, therefore, clinical outcome. Multiple prior biomechanical studies evaluated length-stable fracture models with destructive load-to-failure protocols, which may not represent a clinically relevant failure mode. The current authors compared a lateral locked construct with 2 distinct nonlocked constructs in an osteoporotic, segmental fibula defect model. Eighteen adult cadaveric ankles were randomized to a one-third tubular plate with nonlocking screws, a precontoured fibular plate with nonlocking screws, or the same pre-contoured plate with locking screws. Each was nondestructively loaded with an external rotation of 2.5 Nm for 10,000 cycles. The primary outcome was the change in construct stiffness. Secondary outcomes included maximal rotational displacement and change in insertion torques. Average increase in stiffness of the one-third tubular plate was 0.35 Nm/degree (P<.001), which was significantly greater than that in the nonlocking and locking precontoured plates (0.15 and 0.17 Nm/degree, respectively; P=.69). All 3 constructs externally rotated to 11.7°±4.6°, 8.6°±3.6°, and 10.9°±4.7°, respectively (P=.50). Average loss of insertion torque in the 4 proximal positions was 32.7%±19%, 41.3%±20.2%, 57.8%±19%, and 64.9%±29.2% (P>.05). Average loss in the 4 distal positions for nonlocking constructs (71.6%±21%, 70.4%±26.4%, 93.1%±11%, and 83.3%±35.4%) was significantly different from that for the locking construct (15%±21.4%, 11.7%±24%, 9.2%±9.2%, and 20.8%±23.3%) (P<.05). No evidence in the current study supports the use of a locking plate for osteoporotic specimens. PMID:24093701

Lo, Eddie Y; Tseng, Susan S; Christiansen, Blaine A; Lee, Mark A; Yoo, Brady J

2013-10-01

150

A comparative analysis of Ender's-rod and compression screw and side plate fixation of intertrochanteric fractures of the hip.  

PubMed

The purpose of this study is to compare the results of compression screw fixation and Ender's rods in the treatment of intertrochanteric fractures of the hip. A retrospective analysis of 77 cases of both unstable and stable cases of intertrochanteric fractures showed a higher incidence of complications in the Ender's group; these included backing out, distal femur fracture, need for a secondary procedure, external rotation deformity, and knee pain. Indications for the use of Ender's rods may be found among patients with burns, soft-tissue injuries of the proximal thigh, and patients refusing blood transfusions. Wiring of the distal ends of Ender's rods prevents backing out of the rods. Dacron tape has also been successfully used to prevent the distal ends of the rods from backing out in the last six of the 77 cases. The compression hip screw is a preferred treatment of choice in both stable and unstable intertrochanteric fractures. PMID:2364601

Rao, J P; Hambly, M; King, J; Benevenia, J

1990-07-01

151

Improving greater trochanteric reattachment with a novel cable plate system.  

PubMed

Cable-grip systems are commonly used for greater trochanteric reattachment because they have provided the best fixation performance to date, even though they have a rather high complication rate. A novel reattachment system is proposed with the aim of improving fixation stability. It consists of a Y-shaped fixation plate combined with locking screws and superelastic cables to reduce cable loosening and limit greater trochanter movement. The novel system is compared with a commercially available reattachment system in terms of greater trochanter movement and cable tensions under different greater trochanteric abductor application angles. A factorial design of experiments was used including four independent variables: plate system, cable type, abductor application angle, and femur model. The test procedure included 50 cycles of simultaneous application of an abductor force on the greater trochanter and a hip force on the femoral head. The novel plate reduces the movements of a greater trochanter fragment within a single loading cycle up to 26%. Permanent degradation of the fixation (accumulated movement based on 50-cycle testing) is reduced up to 46%. The use of superelastic cables reduces tension loosening up to 24%. However this last improvement did not result in a significant reduction of the grater trochanter movement. The novel plate and cables present advantages over the commercially available greater trochanter reattachment system. The plate reduces movements generated by the hip abductor. The superelastic cables reduce cable loosening during cycling. Both of these positive effects could decrease the risks related to grater trochanter non-union. PMID:22749768

Baril, Yannick; Bourgeois, Yan; Brailovski, Vladimir; Duke, Kajsa; Laflamme, G Yves; Petit, Yvan

2012-07-01

152

Treatment of posterior pelvic ring injuries with minimally invasive percutaneous plate osteosynthesis  

PubMed Central

From January 2004 to July 2007, 21 patients with injuries at the posterior pelvic ring were treated with locking compression plate osteosynthesis through a minimally invasive approach and followed up for a mean of 12.2 months. Preoperative and postoperative radiography was conducted to assess the reduction and union. The mean operation time was 60 minutes (range: 40–80). Intraoperative blood loss was 50–150 ml. All patients achieved union at the final follow-up. The overall radiological results were excellent or good in 17 patients (85%). The functional outcome was excellent or good in 18 patients (90%). There was no iatrogenic nerve injury, deep infection or failure of fixation. We believe that fixation with a locking compression plate is an effective method for the treatment of injuries of the posterior pelvic ring in view of its convenience, minimal traumatic invasion and lower morbidity.

Hao, Tang

2009-01-01

153

Comparative evaluation of the Rose Bengal plate test, standard tube agglutination test and complement fixation test for the diagnosis of human brucellosis.  

PubMed

In this study, 241 serum samples from individuals exposed to brucellosis were subjected to the Rose Bengal plate test (RBPT); the titre was estimated by standard tube agglutination test (STAT), with positive > or = 80 IU/ml. Randomly selected sera (n = 81) were analysed by complement fixation test (CFT): titre > or = 1:4 was considered positive. Of 241 sera subjected to RBPT and STAT, 177 were negative in both tests; 5 samples tested negative by RBPT but positive by STAT. None was positive by RBPT and negative by STAT. Of 81 sera subjected to CFT, 23 (28.4%) were positive. Both RBPT and CFT found 18 samples positive; 5 samples were positive by CFT and negative by RBPT. Comparison of STAT with CFT showed 13 samples positive by STAT but negative by CFT, and 4 positive by CFT but negative by STAT. The sensitivity and specificity of STAT were 82.6% and 77.6%, respectively, with CFT as gold standard. No test is perfect, and the clinical history coupled with a combination of two or more tests will reduce diagnostic errors. PMID:23520751

Yohannes, M; Gill, J P S; Ghatak, S; Singh, D K; Tolosa, T

2012-12-01

154

44. LOCK AND DAM NO. 26 (REPLACEMENT). LOCK LOCK ...  

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

44. LOCK AND DAM NO. 26 (REPLACEMENT). LOCK -- LOCK GUIDEWALLS -DOWNSTREAM GUIDEWALL, PARTIAL ISOMETRIC VIEW. M-L 26(R) 26/40 - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

155

A case of hypertrophic ischial tuberosity non-union treated by closed wedge osteotomy and plate and screws fixation.  

PubMed

We report a case of a 21-year-old male with massive hypertrophic ischial tuberosity non-union. Among multiple other lesions, the patient suffered an open avulsion of the ischial tuberosity in a severe traffic accident in adolescence. A conservative treatment was decided for the avulsion. Because of sciatic pain and difficulties while sitting since the age of 19, X-rays were realised and showed a massive hypertrophic non-union of the ischial tuberosity. To preserve hamstring origin with bone attachment, the non-union was mobilised, reduced by osteotomy and fixed by plate and screws. At the follow up of one year, the patient sits without pain and can work without interruption. Avulsion of the ischial tuberosity is infrequent and the diagnosis is often missed (Gidwani et al., BMJ 329:99-100, 2004; Hamada, Clin Orthop 31:117-130, 1963). This lesion is more often seen in adolescence as the consequence of a sport injury (Gidwani et al., BMJ 329:99-100, 2004). Treatment is generally conservative and outcome good. Surgical therapy is only needed in cases with severe displacement. Long-term problems are seldom and surgical therapy to solve these problems is the exception. PMID:23411936

Putman, S; Rommens, P M

2013-02-15

156

In vitro biomechanical evaluation of the effect of an additional L-shaped plate on straight or box plate fixation in sagittal split ramus osteotomy using a bioabsorbable plate system  

Microsoft Academic Search

Purpose  Relapse caused by clockwise (opening) rotation of the distal segment (dentate segment) in the sagittal plane is one of the\\u000a postoperative complications sometimes seen after sagittal split ramus osteotomy. The force involved in this movement is primarily\\u000a exerted by the masticatory and suprahyoid muscles. For postoperative stability, we have used two plates on each side: a straight\\u000a plate placed over

Kazuhiro Matsushita; Nobuo Inoue; Yasunori Totsuka

157

Valve lock  

NASA Astrophysics Data System (ADS)

A valve security lock is provided which secures a double union ball valve. The lock is formed from a band inserted through slits in a tube, with that combination being positioned over the valve stem to be secured, and the ends of the band wrapped around the circumference of the double union ball valve. The apparatus is secured around the double union ball valve by insertion of the shank of a lock of known kind through holes in the ends of the band. In a fluid control system, the valve security lock provides a highly visible means to prevent accidental turn-ons or turn-offs during system maintenance, but which can be easily disengaged by persons having the key or combination to the shank type lock.

Burley, Richard K.; Guirguis, Kamal S.

1992-11-01

158

Locking Hinge.  

National Technical Information Service (NTIS)

The space station configuration currently being studied utilizes structures which require struts to be hinged in the middle in stowed configuration and locked into place in the deployed configuration. Since there are hundreds of hinges involved, it is nec...

C. J. Wesselski

1986-01-01

159

Multifragmentary Tibial Pilon Fractures: Midterm Results After Osteosynthesis with External Fixation and Multiple Lag Screws  

PubMed Central

Osteosynthesis of intraarticular tibial pilon fractures is preferably achieved using locking plates via a minimally invasive technique. If combined with severe soft tissue damage there is a high risk of wound-healing deficits after plate osteosynthesis. Thus our aim was to find an alternative method of treatment for those cases with combined soft tissue injuries. We report on five cases with comminuted fractures of the joint surface combined with critical soft tissue condition that were treated with lag screws and external fixation (AO) applied across the ankle joint. All five patients were followed up, undergoing clinical and radiological examination. Using this approach we achieved fracture healing of comminuted fractures without further complications. Clinical follow-up after an average of 55.6 (36–75) months revealed a mean AOFAS score of 81 (62–100). We therefore propose combined treatment using lag screws with external fixation as a practical treatment option for those fractures for which lag screws combined with a locking plate are not feasible or when there is a high risk of wound-healing deficits due to severe soft tissue damage.

Kiene, Johannes; Herzog, Jan; Jurgens, Christian; Paech, Andreas

2012-01-01

160

Displaced midshaft fractures of the clavicle: non-operative treatment versus plate fixation (Sleutel-TRIAL). A multicentre randomised controlled trial  

PubMed Central

Background The traditional view that the vast majority of midshaft clavicular fractures heal with good functional outcomes following non-operative treatment may be no longer valid for all midshaft clavicular fractures. Recent studies have presented a relatively high incidence of non-union and identified speciic limitations of the shoulder function in subgroups of patients with these injuries. Aim A prospective, multicentre randomised controlled trial (RCT) will be conducted in 21 hospitals in the Netherlands, comparing fracture consolidation and shoulder function after either non-operative treatment with a sling or a plate fixation. Methods/design A total of 350 patients will be included, between 18 and 60 years of age, with a dislocated midshaft clavicular fracture. The primary outcome is the incidence of non-union, which will be determined with standardised X-rays (Antero-Posterior and 30 degrees caudocephalad view). Secondary outcome will be the functional outcome, measured using the Constant Score. Strength of the shoulder muscles will be measured with a handheld dynamometer (MicroFET2). Furthermore, the health-related Quality of Life score (ShortForm-36) and the Disabilities of Arm, Shoulder and Hand (DASH) Outcome Measure will be monitored as subjective parameters. Data on complications, bone union, cosmetic aspects and use of painkillers will be collected with follow-up questionnaires. The follow-up time will be two years. All patients will be monitored at regular intervals over the subsequent twelve months (two and six weeks, three months and one year). After two years an interview by telephone and a written survey will be performed to evaluate the two-year functional and mechanical outcomes. All data will be analysed on an intention-to-treat basis, using univariate and multivariate analyses. Discussion This trial will provide level-1 evidence for the comparison of consolidation and functional outcome between two standardised treatment options for dislocated midshaft clavicular fractures. The gathered data may support the development of a clinical guideline for treatment of clavicular fractures. Trial registration Netherlands National Trial Register NTR2399

2011-01-01

161

21 CFR 888.3060 - Spinal intervertebral body fixation orthosis.  

Code of Federal Regulations, 2013 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3060 Spinal intervertebral body fixation...fixation orthosis is a device intended to be implanted made of titanium. It consists of various vertebral plates that are...

2013-04-01

162

Healing Results of Periprosthetic Distal Femur Fractures Treated with Far Cortical Locking Technology: A Preliminary Retrospective Study  

PubMed Central

Introduction Periprosthetic distal femur fractures are severe injuries occurring in the often osteoporotic bone of the elderly. Far cortical locking (FCL) screws, which have been shown to promote increased callus formation in animal models, have recently become available for clinical use. The purpose of this study is to report preliminary healing and complication rates of periprosthetic distal femur fractures treated with FCL constructs. Materials and Methods A retrospective review of 20 patients who underwent open reduction and internal fixation of periprosthetic distal femur fractures using FCL constructs was performed. Healing was assessed radiographically and clinically at 6, 12 and 24 weeks post-operatively. Construct failure was defined as any hardware breakage or bone-implant dissociation leading to loss of reduction. Results Complete data through the 24 week study period was available for 18/20 patients. Bridging callus was identified in 16/18 patients by the 24 week follow up for a healing rate of 88.9%. In patients that healed, the average time to medial bridging callus formation was 10.7±6.7 weeks, 11.0±6.6 weeks for anterior fracture line and 13.4±7.5 weeks for the posterior fracture line. both patients that failed to heal underwent revision surgery. Discussion The initial results of this study are comparable to results reported for distal femur periprosthetic fractures treated with locking plate fixation without FCL screws, although it was difficult to compare time to healing between previously published studies. It is the impression of the authors that callus appears earlier and is more robust and uniform between the three cortices in FCL cases compared to their previous experiences with traditional locking plate periprosthetic distal femur fractures. This work suggests that FCL screws may be superior to traditional locking constructs but further studies are needed to directly compare the two methods.

Ries, Zachary; Hansen, Kirk; Bottlang, Michael; Madey, Steven; Fitzpatrick, Daniel; Marsh, J.L.

2013-01-01

163

Titanium plate artefact mimicking popliteal artery dissection on digital subtraction CT angiography.  

PubMed

Titanium plates used for the internal fixation of long bone fractures cause significant artefact on CT scans but have not been reported to affect digital subtraction CT angiography. We present a patient with clinical suspicion of popliteal artery injury following a high tibial osteotomy. The osteotomy was stabilised with a titanium locking plate. During the digital subtraction process used to produce reconstruction CT angiography, removal of artefact caused by the titanium plate produced CT images mimicking the appearance of a popliteal artery dissection. The imaging inaccuracy was realised prior to the patient undergoing further intervention. We highlight the potential error caused by titanium plates on digital subtraction CT angiography and recommend careful analysis of such images prior to further treatment. PMID:23563677

Woodacre, Timothy; Wienand-Barnett, Sophie

2013-04-05

164

Tectonic Plates and Plate Boundaries  

NSDL National Science Digital Library

Continents were once thought to be static, locked tight in their positions in Earth's crust. Similarities between distant coastlines, such as those on opposite sides of the Atlantic, were thought to be the work of a scientist's overactive imagination, or, if real, the result of erosion on a massive scale. This interactive feature shows 11 tectonic plates and their names, the continents that occupy them, and the types of boundaries between them.

2011-05-09

165

Tectonic Plates and Plate Boundaries  

NSDL National Science Digital Library

Continents were once thought to be static, locked tight in their positions in Earth's crust. Similarities between distant coastlines, such as those on opposite sides of the Atlantic, were thought to be the work of a scientist's overactive imagination, or, if real, the result of erosion on a massive scale. This interactive feature shows 11 tectonic plates and their names, the continents that occupy them, and the types of boundaries between them.

166

Low-profile titanium plate construct for early weightbearing with first metatarsophalangeal joint arthrodesis.  

PubMed

First metatarsophalangeal joint arthrodesis is a useful procedure for various first ray pathologic entities. Multiple constructs for fixation have provided successful fusion. A retrospective study of 21 feet (18 patients) was performed after first metatarsophalangeal joint fusion using crossed Kirschner wires or compression fixation with cannulated screws followed by the application of a 2-hole low-profile partially locking titanium plate. The median age was 59 (range 41 to 76) years, and we had 4 smokers and 3 patients with diabetes in our series. Postoperatively, a compression dressing with a posterior splint was applied. The patients then transitioned to a controlled ankle motion walker, and all patients reported full weightbearing by 2 weeks postoperatively. The mean follow-up duration was 11.43 (range 6 to 27) months. The overall primary fusion rate was 95.24% (20 of 21). Two nonunions occurred; one was asymptomatic and successfully consolidated at 12 months. The second nonunion required revisional surgery with an autogenous bone graft to heal successfully. This patient was noncompliant with the postoperative regimen and had a 48-pack year history of tobacco usage. Our results have shown early weightbearing after first metatarsophalangeal joint arthrodesis can be successfully initiated with splintage or lag screw fixation and a 2-hole, low-profile, partially locking titanium plate. PMID:23632068

Mann, Joshua J; Moon, Jared L; Brosky, Thomas A

2013-04-28

167

Minimally invasive poly-axial screw plating for three-part fractures of the proximal humerus.  

PubMed

The purpose of this study was to evaluate the poly-axial locked plating system inserted through a minimally invasive approach for the treatment of three-part fractures of the proximal humerus. Twenty-three patients with a three-part fracture of the proximal humerus treated with a poly-axial locking plate through a percutaneous approach were available for clinical and radiological analysis at a minimum of 2 years follow up (average 36 months; range, 24-54 months). To assess objective and subjective outcomes the Constant Score (CS) and the Disabilities of the Arm, Shoulder, and Hand (DASH) score were obtained. All complications were recorded. There were 17 women and 6 men, with a mean age of 62 years (range, 18-86). All fractures healed. At final follow up, the mean forward flexion, external rotation and internal rotation were 126°, 44° and L1, respectively; the mean CS was 64 and the mean DASH score was 23. Twelve patients (52%) had a postoperative complication, which included screw cut-out, stiffness and infection. The poly-axial locked plating system through a minimally-invasive approach may be an appropriate treatment for three-part fractures of the proximal humerus and may reduce the biological aggression of conventional plate fixation. PMID:23622997

Barco, R; Barrientos, I; Encinas, C; Antuña, S A

2012-12-01

168

Fixation of periprosthetic femoral shaft fractures occurring at the tip of the stem  

Microsoft Academic Search

This study evaluated 5 currently used periprosthetic femoral shaft fracture fixation techniques to determine which technique provided the greatest fixation stability. Periprosthetic fractures in 30 synthetic femurs were fixed with a plate with cables, plate with proximal cables and distal bicortical screws (Ogden concept), plate with proximal unicortical screws and distal bicortical screws, plate with proximal unicortical screws and cables

Michael G Dennis; Jordan A Simon; Frederick J Kummer; Kenneth J Koval; Paul E DiCesare

2000-01-01

169

Development and mechanical testing of a short intramedullary nail for fixation of femoral rotational osteotomy in cerebral palsy patients  

PubMed Central

Background Rotational osteotomy is frequently indicated to correct excessive femoral anteversion in cerebral palsy patients. Angled blade plate is the standard fixation device used when performed in the proximal femur, but extensile exposure is required for plate accommodation. The authors developed a short locked intramedullary nail to be applied percutaneously in the fixation of femoral rotational osteotomies in children with cerebral palsy and evaluated its mechanical properties. Methods The study was divided into three stages. In the first part, a prototype was designed and made based on radiographic measurements of the femoral medullary canal of ten-year-old patients. In the second, synthetic femoral models based on rapid-prototyping of 3D reconstructed images of patients with cerebral palsy were obtained and were employed to adjust the nail prototype to the morphological changes observed in this disease. In the third, rotational osteotomies were simulated using synthetic femoral models stabilized by the nail and by the AO-ASIF fixed-angle blade plate. Mechanical testing was done comparing both devices in bending-compression and torsion. Results The authors observed proper adaptation of the nail to normal and morphologically altered femoral models, and during the simulated osteotomies. Stiffness in bending-compression was significantly higher in the group fixed by the plate (388.97 ± 57.25 N/mm) than in that fixed by the nail (268.26 ± 38.51 N/mm) as torsional relative stiffness was significantly higher in the group fixed by the plate (1.07 ± 0.36 Nm/°) than by the nail (0.35 ± 0.13 Nm/°). Conclusions Although the device presented adequate design and dimension to fit into the pediatric femur, mechanical tests indicated that the nail was less stable than the blade plate in bending-compression and torsion. This may be a beneficial property, and it can be attributed to the more flexible fixation found in intramedullary devices.

2011-01-01

170

Concurrent programming without locks  

Microsoft Academic Search

Mutual exclusion locks remain the de facto mechanism for concurrency control on shared-memory data structures. However, their apparent simplicity is deceptive: It is hard to design scalable locking strategies because locks can harbor problems such as priority inversion, deadlock, and convoying. Furthermore, scalable lock-based systems are not readily composable when building compound operations. In looking for solutions to these problems,

Keir Fraser; Tim Harris

2007-01-01

171

Is a single anterolateral screw-plate fixation sufficient for the treatment of spinal fractures in the thoracolumbar junction? A Biomechanical in vitro Investigation  

Microsoft Academic Search

Controversy exists about the indications, advantages and disadvantages of various surgical techniques used for anterior interbody fusion of spinal fractures in the thoracolumbar junction. The purpose of this study was to evaluate the stabilizing effect of an anterolateral and thoracoscopically implantable screw-plate system. Six human bisegmental spinal units (T12–L2) were used for the biomechanical in vitro testing procedure. Each specimen

Ulrich Schreiber; Tibor Bence; Thomas Grupp; Erwin Steinhauser; Thomas Mückley; Wolfram Mittelmeier; Rudolf Beisse

2005-01-01

172

Biomechanical analysis of olecranon fracture fixation in children.  

PubMed

The authors present an original fixation technique for olecranon fractures in children, achievable without opening the fracture site. The standard method of Kirschner wire fixation with tension band wiring is replaced by a threaded pin stabilization with adjustable lock effect. An olecranon fracture model was used to compare the mechanical properties of this new system with the tension band wiring technique, and with a simple pin fixation. No significant difference was found between the two first techniques, whereas the simple pin fixation had much poorer mechanical properties. PMID:11744847

Gicquel, Philippe; Maximin, Marie-Christine; Boutemy, Philippe; Karger, Claude; Kempf, Jean-François; Clavert, Jean-Michel

173

Seismicity near the slip maximum of the 1960 Mw 9.5 Valdivia earthquake (Chile): Plate interface lock and reactivation of the subducted Valdivia Fracture Zone  

NASA Astrophysics Data System (ADS)

Understanding the processes behind subduction-related hazards is an important responsibility and major challenge for the Earth sciences. Few areas demonstrate this as clearly as south-central Chile, where some of the largest earthquakes in human history have occurred. We present the first observation of local seismicity in the Villarrica region (39°-40°S), based on a temporary local network of 55 stations installed from the Chilean coast into the Argentinian back-arc for one year. While consistent with the Chilean national catalog (SSN), our results allow us to observe smaller magnitudes with a completeness of about 2.0 and image the geometry of the Wadati-Benioff Zone from the Chile Trench down to 200 km. Offshore, a gap in interplate seismicity is observed in the region of the 1960 Valdivia earthquake slip. Above the interface, two offshore seismicity clusters possibly indicate ongoing stress relaxation. In the subducting Nazca Plate, we find a prominent seismicity cluster along the extrapolated trace of the oceanic Valdivia Fracture Zone (VFZ). The seismicity cluster is observed between 70 and 130 km depth and comprises mainly strike-slip events. It indicates weakening and reactivation of the major VFZ by dehydration of oceanic crust and mantle. Interpreting the subducted VFZ section as a localized reservoir of potential fluid release offers an explanation for the Villarrica volcanic complex that is located above the reactivated VFZ and shows the highest volcanic activity in South America. Crustal seismicity is observed near Puyehue volcano, which recently started to erupt (June 2011).

Dzierma, Yvonne; Thorwart, Martin; Rabbel, Wolfgang; Siegmund, Claudia; Comte, Diana; Bataille, Klaus; Iglesia, Paula; Prezzi, Claudia

2012-06-01

174

Locking clutch  

US Patent & Trademark Office Database

A locking clutch comprises a toothed member and a slide assembly which are connectable to drive and driven parts. The two members are movable between an engaged position in which the clutch transfers power and/or torque to the driven part and a disengaged position in which power and/or torque is not transferred. The toothed member comprises a cylindrical surface and a plurality of teeth spaced about and extending from the cylindrical surface. The slide assembly comprises a body having a circumferential surface with a plurality of channels formed in said surface. Slide members are received in the channels to be movable between an extended position in which they can engage the teeth of the toothed member and a retracted position in which they do not engage the teeth of the toothed member. A resilient member biases the slide members to their extended positions. The slide assembly can be formed so that the slide members move either axially or radially relative to the slide assembly body.

2004-06-08

175

Distally locked stems in revision hip arthroplasties: surgical technique and indications  

Microsoft Academic Search

In case of severe femoral bone loss, cementless revision hip arthroplasties require a stable initial distal fixation that\\u000a does not compromise a subsequent bone reconstruction. The locking mechanism provides initially reliable fixation, especially\\u000a if bone loss has spread to the distal femoral isthmus or when an extended trochanteric osteotomy (femorotomy) is indicated.\\u000a Locking stems can be used in all types

H. Migaud; O. May; M. Soenen; B. Miletic; P. Deroche; A. Gabrion; P. Mertl; J. Girard

2008-01-01

176

Limb lengthening over plate  

PubMed Central

Background: The limb lengthening over plate eliminates the associated risk of infection with limb lengthening over intramedullary nail. We present our experience of limb lengthening in 15 patients with a plate fixed on the proximal segment, followed by corticotomy and application of external fixator. Materials and Methods: 15 patients (7 females, 8 males) were included in this consecutive series. The average age was 18.1 years (range 8–35 years). Fifteen tibiae and one femur were lengthened in 15 patients. Lengthening was achieved at 1 mm/day followed by distal segment fixation with three or four screws on reaching the target length. Results: The preoperative target length was successfully achieved in all patients at a mean of 4.1 cm (range 1.8–6.5 cm). The mean duration of external fixation was 75.3 days (range 33–116 days) with the mean external fixation index at 19.2 days/cm (range 10.0–38.3 days/cm). One patient suffered deep infection up to the plate, three patients had mild procurvatum deformities, and one patient developed mild tendo achilles contracture. Conclusion: Lengthening over a plate allows early removal of external fixator and eliminates the risk of creating deep intramedullary infection as with lengthening over nail. Lengthening over plate is also applicable to children with open physis.

Kulkarni, Ruta; Singh, Nishant; Kulkarni, Govind S; Kulkarni, Milind; Kulkarni, Sunil; Kulkarni, Vidisha

2012-01-01

177

Parallel plating for a sternomanubrial dislocation.  

PubMed

Sternomanubrial dislocations are rare injuries. Although few cases of this injury have been reported in the literature, the etiology has varied widely: trampoline injury, seizures, falls from height, sporting injuries, gradual deformities from spine fractures, and motor vehicle collisions. This injury has been classified into 2 types: in type I, the sternal body is displaced posteriorly to the manubrium, and in the more common type II, the sternal body is displaced anteriorly. The sternomanubrial joint is an amphiarthroidal joint that bears hyaline cartilage on both surfaces connected by a fibrocartilage meniscus. It serves a protective role to vital thoracic structures and is an anterior stabilizing strut to the thorax, assisting the thoracic spine in upright stability. It is important to not ignore type I dislocations because posterior sternum displacement is a harbinger of injury to the pulmonary tree, heart, and esophagus. Chronic instability at this joint can lead to dyspnea and dysphasia due to sternum displacement. In the right scenario, type II injuries are occasionally treated conservatively with palliative treatment until the sternum heals with malformation. This article describes the case of a 20-year-old man who was treated surgically for symptomatic type II sternomanubrial dislocation with dual anterior locked plating. Locked plating gives the benefit of unicortical fixation, with the screws and plate acting as a unit to resist motion. Screw pullout and failure is less common, and the construct is more resistant for this application. The patient returned to full participation in activities of daily living and military duty 4 months postoperatively. PMID:22868620

Gaines, Robert J; Wilson, Addison; Antevil, Jared; Demaio, Marlene

2012-08-01

178

Phase Lock Acquisition System.  

National Technical Information Service (NTIS)

The acquisition of phase lock to a reference frequency by a signal acquisition system is accomplished using a voltage controlled oscillator, a wideband frequency discriminator, a prepositioning circuit, and a phase lock loop. The voltage controlled oscill...

S. P. Caldwell

1984-01-01

179

Phase-locked loops  

Microsoft Academic Search

An attempt to systematically outline the work done in the area of phase-locked loops which are now used in modern communication system design is presented. The analog phase-locked loops are well documented in several books but discrete, analog-digital, and digital. phase-locked loop work is scattered. Apart from discussing the various analysis, design, and application aspects of phase-locked loops, a number

S. C. Gupta

1975-01-01

180

ALAIN LOCKE AND COMMUNITY  

Microsoft Academic Search

Locke consistently argues for the importance of cosmopolitan identity, i.e., “cultural-citizenship.” Paradoxically, he also argues for the importance of particular, local, and racial\\/ethnic identities. People have a natural instinct that Locke terms a consciousness of kind, to bond with persons in relatively closed communities. Communities are not natural social groups for Locke, but historical social constructions. I argue that Locke's

LEONARD HARRIS

1997-01-01

181

Fast flux locked loop  

DOEpatents

A flux locked loop for providing an electrical feedback signal, the flux locked loop employing radio-frequency components and technology to extend the flux modulation frequency and tracking loop bandwidth. The flux locked loop of the present invention has particularly useful application in read-out electronics for DC SQUID magnetic measurement systems, in which case the electrical signal output by the flux locked loop represents an unknown magnetic flux applied to the DC SQUID.

Ganther, Jr., Kenneth R. (Olathe, KS); Snapp, Lowell D. (Independence, MO)

2002-09-10

182

Multiversion Query Locking  

Microsoft Academic Search

Multiversion two-phase locking (MV2PL) has been incorporated in some commercial transaction processing systems to support the serializable execution of queries. A drawback to this algo- rithm is the potentially high cost that it adds to maintain and access prior versions of data In this paper, we present a new multiversion locking algorithm, multiversion query locking (MVQL), that reduces the cost

Paul M. Bober; Michael J. Carey

1992-01-01

183

Additive Pulse Mode Locking.  

National Technical Information Service (NTIS)

A new principle of mode locking is analyzed: additive pulse mode locking. It is shown to be operative in two-cavity soliton lasers, but it also permits mode locking with fibers in the positive dispersion regime. A simple model is developed that displays t...

E. P. Ippen H. A. Haus L. Y. Liu

1989-01-01

184

Nonmetallic fixation in elective maxillofacial surgery.  

PubMed

Resorbable fixation technology offers several benefits, including easily cut and shaped plates, strong and predictable resorption qualities, and improved patient acceptance and expectations. Moreover, resorbable fixation implants can be completely reabsorbed into the body, eliminating the need for subsequent removal. This article describes the use of this innovative technology in orthognathic surgery, including preoperative and postoperative patient needs, intraoperative patient care, and potential complications. PMID:10686651

Abernathy, W; McDaniel, M; Edwards, R; Kiely, K; Frazier, D

2000-01-01

185

Fusion and failure following anterior cervical plating with dynamic or rigid plates: 6-months results of a multi-centric, prospective, randomized, controlled study.  

PubMed

Anterior cervical plate fixation is an approved surgical technique for cervical spine stabilization in the presence of anterior cervical instability. Rigid plate design with screws rigidly locked to the plate is widely used and is thought to provide a better fixation for the treated spinal segment than a dynamic design in which the screws may slide when the graft is settling. Recent biomechanical studies showed that dynamic anterior plates provide a better graft loading possibly leading to accelerated spinal fusion with a lower incidence of implant complications. This, however, was investigated in vitro and does not necessarily mean to be the case in vivo, as well. Thus, the two major aspects of this study were to compare the speed of bone fusion and the rate of implant complications using either rigid- or dynamic plates. The study design is prospective, randomized, controlled, and multi-centric, having been approved by respective ethic committees of all participating sites. One hundred and thirty-two patients were included in this study and randomly assigned to one of the two groups, both undergoing routine level-1- or level-2 anterior cervical discectomy with autograft fusion receiving either a dynamic plate with screws being locked in ap - position (ABC, Aesculap, Germany), or a rigid plate (CSLP, Synthes, Switzerland). Segmental mobility and implant complications were compared after 3- and 6 months, respectively. All measurements were performed by an independent radiologist. Mobility results after 6 months were available for 77 patients (43 ABC/34 CSLP). Mean segmental mobility for the ABC group was 1.7 mm at the time of discharge, 1.4 mm after 3 months, and 0.8 mm after 6 months. For the CSLP- group the measurements were 1.0, 1.8, and 1.7 mm, respectively. The differences of mean segmental mobility were statistically significant between both groups after 6 months (P = 0.02). Four patients of the CSLP-group demonstrated surgical hardware complications, whereas no implant complications were observed within the ABC-group (P = 0.0375). Dynamic plate designs provided a faster fusion of the cervical spine compared with rigid plate designs after prior spinal surgery. Moreover, the rate of implant complications was lower within the group of patients receiving a dynamic plate. These interim results refer to a follow-up period of 6 months after prior spinal surgery. Further investigations will be performed 2 years postoperatively. PMID:17684777

Stulik, Jan; Pitzen, Tobias Rainer; Chrobok, Jan; Ruffing, Sabine; Drumm, Jörg; Sova, Laurentius; Kucera, Ravel; Vyskocil, Tomas; Steudel, Wolf Ingo

2007-08-08

186

Locke’s Theology, 1694–1704  

Microsoft Academic Search

\\u000a What follows is a narrative of John Locke’s theological reflections and judgments, expressed in pertinent writings beginning\\u000a with ‘Adversaria theologica’ (1694), and ending with Of the conduct of the understanding (published posthumously in 1706). I hope to show that these reflections and judgments follow a continuous line of enquiry\\u000a and discovery that has its own integrity and may, therefore, be

Victor Nuovo

187

The limited contact dynamic compression plate (LC-DCP)  

Microsoft Academic Search

To realize the new concept of biological internal fixation the limited contact dynamic compression plate was developed. It minimizes vascular damage to the plated bone segment. It should lead to a more versatile and efficient application of internal fixation using plates.

S. M. Perren; K. Mane; O. Pohler; M. Predieri; S. Steinemann; E. Gautier

1990-01-01

188

Intramedullary tibial nailing in distal third tibial fractures: distal locking screws and fracture non-union.  

PubMed

Distal third tibial fractures are prone to non-union following tibial nail insertion. The purpose of this study was to assess the union of distal third tibial fractures in patients who have undergone intra-medullary (IM) tibial nailing with one versus two distal locking screws. Sixty-five patients who had intramedullary tibial nail fixation were retrospectively analysed. Our results showed that 80% of non-unions in distal third fractures had only one distal locking screw compared to 20% who had two distal locking screws. This is statistically significant (p<0.01). We therefore conclude that two distal locking screws are essential for distal third fractures. PMID:17410364

Mohammed, Aso; Saravanan, Ramaswamy; Zammit, Jason; King, Richard

2007-04-05

189

Locke and Environmental Political Theory  

Microsoft Academic Search

Few philosophers’ ideas have had as significant an impact on the natural world as those of John Locke; in particular, an examination of Locke’s account of property is central to any attempt at revealing environmentally significant themes in the traditional political theory canon. many readers have taken Locke’s theory to be utterly inimical to the use of state power to

Zev Trachtenberg

190

Lock 1 View north of wall west of lock ...  

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

Lock 1 - View north of wall west of lock 1. Note the wood pile and plank foundation (believed to be similar under lock 1 walls) - Savannah & Ogeechee Barge Canal, Between Ogeechee & Savannah Rivers, Savannah, Chatham County, GA

191

West Branch Pennsylvania Canal, Lock No. 34 Lock Keeper's House, ...  

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

West Branch Pennsylvania Canal, Lock No. 34 Lock Keeper's House, South of State Route 664 along North bank of West Branch of Susquehanna River, 2,000 feet East of Jay Street Bridge, Lock Haven, Clinton County, PA

192

39. VIEW OF AUXILIARY LOCK MITER GATE, WITH MAIN LOCK ...  

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

39. VIEW OF AUXILIARY LOCK MITER GATE, WITH MAIN LOCK UPSTREAM MITER GATE AND UPSTREAM GUIDEWALL IN BACKGROUND, LOOKING NORTHWEST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 10, Guttenberg, Clayton County, IA

193

49 CFR 236.779 - Plate, top.  

Code of Federal Regulations, 2010 CFR

...Transportation 4 2009-10-01 2009-10-01 false Plate, top. 236.779 Section 236.779 Transportation...DEVICES, AND APPLIANCES Definitions § 236.779 Plate, top. A metal plate secured to a locking bracket to prevent the cross...

2009-10-01

194

49 CFR 236.779 - Plate, top.  

Code of Federal Regulations, 2011 CFR

...Transportation 4 2011-10-01 2011-10-01 false Plate, top. 236.779 Section 236.779 Transportation...DEVICES, AND APPLIANCES Definitions § 236.779 Plate, top. A metal plate secured to a locking bracket to prevent the cross...

2011-10-01

195

49 CFR 236.779 - Plate, top.  

Code of Federal Regulations, 2012 CFR

...Transportation 4 2012-10-01 2012-10-01 false Plate, top. 236.779 Section 236.779 Transportation...DEVICES, AND APPLIANCES Definitions § 236.779 Plate, top. A metal plate secured to a locking bracket to prevent the cross...

2012-10-01

196

49 CFR 236.779 - Plate, top.  

Code of Federal Regulations, 2010 CFR

...Transportation 4 2010-10-01 2010-10-01 false Plate, top. 236.779 Section 236.779 Transportation...DEVICES, AND APPLIANCES Definitions § 236.779 Plate, top. A metal plate secured to a locking bracket to prevent the cross...

2010-10-01

197

Retrospective Comparison of Percutaneous Fixation and Volar Internal Fixation of Distal Radius Fractures  

PubMed Central

A change in the practice of a single surgeon provided an opportunity for retrospective comparison of comparable cohorts treated with percutaneous fixation (17 patients) or a volar plate and screws (23 patients) an average of 30 months after surgery. The final evaluation was performed according to the Gartland and Werley and Mayo rating systems and the DASH questionnaire. There were no significant differences on the average scores for the percutaneous and volar plating groups, respectively: Gartland and Werley, 4 vs 5; Mayo, 82 vs 83; and DASH score 13 for both cohorts. Motion, grip, and radiographical parameters were likewise comparable. Volar internal plate and screw fixation can achieve results comparable to percutaneous fixation techniques in the treatment of fractures of the distal radius.

Lozano-Calderon, Santiago A.; Doornberg, Job N.

2007-01-01

198

Protective air lock  

DOEpatents

A device suitable for preventing escape and subsequent circulation of toxic gases comprising an enclosure which is sealed by a surrounding air lock, automatic means for partially evacuating said enclosure and said air lock and for ventilating said enclosure and means for disconnecting said enclosure ventilating means, whereby a relatively undisturbed atmosphere is created in said enclosure.

Evans, Herbert W. (Scarsdale, NY)

1976-03-30

199

INNOVATIVE FINITE ELEMENT METHODS FOR PLATES  

Microsoft Academic Search

Finite element methods for the Reissner{Mindlin plate theory are discussed. Methods in which both the tranverse displacement and the rotation are approximated by nite elements of low degree mostly suer from locking. However a number of related methods have been devised recently which avoid locking eects. Although the nite element spaces for both the rotation and transverse displacement contain little

DOUGLAS N. ARNOLDy

200

Enhancing Biological Nitrogen Fixation.  

National Technical Information Service (NTIS)

The report summarizes present understanding of the broad area of the chemical and biological aspects of nitrogen fixation. It suggests: (a) opportunities for increasing fixation by leguma-bacterial and other types of systems, (b) approaches toward extendi...

H. J. Evans

1975-01-01

201

35. INTERIOR VIEW OF THE GUARD LOCKS LOCK HOUSE: CLOSED ...  

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

35. INTERIOR VIEW OF THE GUARD LOCKS LOCK HOUSE: CLOSED LOCK GATES AND TWO SETS OF MACHINERY TO ASSIST IN OPERATING THEM. VIEW FROM THE FAST END OF THE BUILDING LOOKING WEST 1976 - Pawtucket Canal, Guard Locks, Lowell, Middlesex County, MA

202

Optical injection locking and phase-lock loop combined systems.  

PubMed

Optical injection locking and optical phase-lock loops have been used for laser synchronization. The use of a combined optical injection locking and phase-lock loop system is proposed here. We have taken into account the modification of the slave laser phase response induced by the injection locking to calculated the phase-error signal spectrum and the phase-error variance for an optical injection locking and phase-lock system. They show that this system presents both a wide locking range, given by the optical injection locking action, and a low phase error for low frequencies, given by the optical phase-lock loop action. These results can improve the system tracking capability and decrease the final phase-error variance compared with those in isolated systems. PMID:19829524

Ramos, R T; Gallion, P; Erasme, D; Seeds, A J; Bordonalli, A

1994-01-01

203

Locke’s Religious Thinking and His Politics  

Microsoft Academic Search

\\u000a The expression ‘Locke’s religious thinking’ can be taken in two ways, one religious and the other not or not-necessarily so:\\u000a it may signify either Locke’s religious thoughts or his thoughts about religion. There is no doubt that Locke thought a lot\\u000a about religion. The question is whether any of these thoughts were religiously meant or motivated. Something like the same

Victor Nuovo

204

Adapter plate assembly for adjustable mounting of objects  

DOEpatents

An adapter plate and two locking discs are together affixed to an optic table with machine screws or bolts threaded into a fixed array of internally threaded holes provided in the table surface. The adapter plate preferably has two, and preferably parallel, elongated locating slots each freely receiving a portion of one of the locking discs for secure affixation of the adapter plate to the optic table. A plurality of threaded apertures provided in the adapter plate are available to attach optical mounts or other devices onto the adapter plate in an orientation not limited by the disposition of the array of threaded holes in the table surface. An axially aligned but radially offset hole through each locking disc receives a screw that tightens onto the table, such that prior to tightening of the screw the locking disc may rotate and translate within each locating slot of the adapter plate for maximum flexibility of the orientation thereof.

Blackburn, R.S.

1986-05-02

205

Plate Tectonics: Plate Interactions  

NSDL National Science Digital Library

This Science Object is the fourth of five Science Objects in the Plate Tectonic SciPack. It identifies the events that may occur and landscapes that form as a result of different plate interactions. The areas along plate margins are active. Plates pushing against one another can cause earthquakes, volcanoes, mountain formation, and very deep ocean trenches. Plates pulling apart from one another can cause smaller earthquakes, magma rising to the surface, volcanoes, and oceanic valleys and mountains from sea-floor spreading. Plates sliding past one another can cause earthquakes and rock deformation. Learning Outcomes:� Explain why volcanoes and earthquakes occur along plate boundaries. � Explain how new sea floor is created and destroyed.� Describe features that may be seen on the surface as a result of plate interactions.

National Science Teachers Association (NSTA)

2006-11-01

206

Multistability and hysteresis phenomena in passively mode-locked fiber lasers  

Microsoft Academic Search

A passively mode-locked fiber laser is theoretically investigated. The mode locking is achieved using the nonlinear polarization technique. We consider the practical case of the ytterbium-doped fiber laser operating in the normal dispersion regime. The effect of the phase plates is explicitly taken into account. The resulting model reduces to one iterative equation for the optical Kerr nonlinearity, the phase

Andrey Komarov; Hervé Leblond; François Sanchez

2005-01-01

207

Plate Tectonics: Plates  

NSDL National Science Digital Library

This Science Object is the second of five Science Objects in the Plate Tectonics SciPack. It provides a conceptual understanding of what plates are and how they move, contributing to a constantly changing surface. The Earth's continents and ocean basins are made up of plates consisting of the crust and the upper part of the mantle. One plate can consist of both continental and oceanic crust. These plates move very slowly (an inch or so per year) on the hot, deformable layer of the mantle beneath them. The outward transfer of Earth's internal heat drives convection circulation in the mantle. This convection, together with gravitational pull on the plates themselves, causes the plates to move. Learning Outcomes:� Identify that the outermost layer of Earth is made up of separate plates.� Choose the correct speed of the motion of plates.� Identify the ocean floor as plate, in addition to the continents (to combat the common idea that only continents are plates, floating around on the oceans).� Recognize that oceans and continents can coexist on the same plate.

National Science Teachers Association (NSTA)

2006-11-01

208

Pressure locking test results  

SciTech Connect

The U.S. Nuclear Regulatory Commission (NRC), Office of Nuclear Regulatory Research, is funding the Idaho National Engineering Laboratory (INEL) in performing research to provide technical input for their use in evaluating responses to Generic Letter 95-07, {open_quotes}Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves.{close_quotes} Pressure locking and thermal binding are phenomena that make a closed gate valve difficult to open. This paper discusses only the pressure locking phenomenon in a flexible-wedge gate valve; we will publish the results of our thermal binding research at a later date. Pressure locking can occur when operating sequences or temperature changes cause the pressure of the fluid in the bonnet (and, in most valves, between the discs) to be higher than the pressure on the upstream and downstream sides of the disc assembly. This high fluid pressure presses the discs against both seats, making the disc assembly harder to unseat than anticipated by the typical design calculations, which generally consider friction at only one of the two disc/seat interfaces. The high pressure of the bonnet fluid also changes the pressure distribution around the disc in a way that can further contribute to the unseating load. If the combined loads associated with pressure locking are very high, the actuator might not have the capacity to open the valve. The results of the NRC/INEL research discussed in this paper show that the relationship between bonnet pressure and pressure locking stem loads appears linear. The results also show that for this valve, seat leakage affects the bonnet pressurization rate when the valve is subjected to thermally induced pressure locking conditions.

DeWall, K.G.; Watkins, J.C.; McKellar, M.G.; Bramwell, D.

1996-06-01

209

Delayed degradation in a resorbable plating system.  

PubMed

Resorbable plating systems are used extensively for craniofacial reconstruction, particularly in children. The systems provide rigid fixation while potentially minimizing the long-term drawbacks of permanent plating systems such as plate "migration," bone growth restriction, and imaging artifact. However, the need for active plate resorption represents both the strength and weakness of these fixation systems. We present four patients who underwent cranial vault remodeling using a resorbable plating system, following which the plates were palpable and observable for at least 2 years postoperatively. All required surgical removal. On gross inspection, the plates had been replaced by an encapsulated spongy material containing yellow, grainy, cloudy liquid. The bone underlying the plates was depressed and irregular in contour when compared with the adjacent bone. Microscopic studies showed a giant cell foreign-body reaction with crystalline material present in the cell vacuoles. PMID:16432435

Mackool, Richard; Yim, Jun; McCarthy, Joseph G

2006-01-01

210

Photographic fixative poisoning  

MedlinePLUS

Photographic developer poisoning; Hydroquinone poisoning; Quinone poisoning; Sulfite poisoning ... Hydroquinones Quinones Sodium thiosulfate Sodium sulfite/bisulfite Boric acid Photographic fixative can also break down (decompose) to ...

211

Lock 1 View northwest of lock entrance. Notch for ...  

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

Lock 1 - View northwest of lock entrance. Notch for flash boards can be seen near center, gate pocket at left. - Savannah & Ogeechee Barge Canal, Between Ogeechee & Savannah Rivers, Savannah, Chatham County, GA

212

Treatment of comminuted olecranon fractures with olecranon plate and structural iliac crest graft.  

PubMed

Severely comminuted olecranon fractures are challenging injuries. Commonly used tension band wiring exerts excessive compressive forces causing olecranon shortening, joint incongruity and humeral trochlea subluxation. We report a retrospective study of 3 patients who underwent surgery for a severely comminuted olecranon fracture, with open reduction and fixation with a bridging rigid locking plate and intercalary tricortical structural iliac bone graft. Joint stability was restored allowing early mobilization and good functional outcome. Patients' mean age was 54 years. Mean follow-up was 23 months (range 19 to 27). Mean time to fusion was 14 weeks (range 11 to 18). Results were excellent/good in all three patients according the Broberg and Morrey scoring system, and Mayo Elbow Performance Index. Mean range of flexion was 115 degrees, with an average loss of 20 degrees of extension. Average pronation was 71 degrees, and supination 80 degrees. PMID:23409563

Cervera-Irimia, Javier; Tomé-Bermejo, Félix; Gómez-Bermejo, María A; Holgado-Moreno, Esperanza; Stratenwerth, Enrique Garrido

2012-12-01

213

Injection locking of excimer lasers  

SciTech Connect

Reliable injection locking of high-power unstable resonator excimer lasers can be achieved with extremely low reference oscillator power. The criteria for injection locking are discussed and experimental results are given.

Bigio, I.J.; Slatkine, M.

1981-01-01

214

Locking Mechanism for Orthopedic Braces.  

National Technical Information Service (NTIS)

A locking mechanism for orthopedic braces is described which automatically prevents or permits the relative pivotable movement between a lower brace member and an upper brace member, the locking mechanism also including a secondary manually operable latch...

J. I. L. Chao C. H. Epps

1977-01-01

215

External fixation for the uninfected angulated nonunion of the tibia.  

PubMed

External skeletal fixation is an effective method of stabilizing angulated ununited fractures of the tibia. In 14 patients who were not infected, realignment was accomplished by: closed-fracture-site manipulation (five cases); fibular osteotomy and closed manipulation (six cases); or fibular osteotomy and open reduction (three cases). External fixation was selected instead of internal fixation for patients in whom there was: risk of reactivating quiescent sepsis; thin secondary epithelium adherent to bone that might slough after surgical dissection; a very proximal or a very distal nonunion, where internal fixation is technically difficult; or a bulky, angulated delayed union or nonunion or one in bayonet apposition that would require excessive plate contouring. On the average, patients were corrected from 17.3 degrees (either varus or valgus) to 2.3 degrees. Two patients did not unite with the fixator/orthosis treatment plan, but neither one lost correction during subsequent management. The technique is not suitable for atrophic nonunions. PMID:6488633

Green, S A; Garland, D E; Moore, T J; Barad, S J

1984-11-01

216

Locke's ideology of ‘common sense’  

Microsoft Academic Search

Recent studies of the social and political meanings of English science in the 17th century have often included only a cursory inspection of Locke's work. Conversely, detailed studies of Locke's theory of knowledge have tended to refrain from taking into serious consideration the social context of English science in that period. The paper explores the contribution of Locke's conception of

Michael Ben-Chaim

2000-01-01

217

Guide to radiation fixatives  

SciTech Connect

This report identifies and then characterizes a variety of substances available in the market place for potential effectiveness as a fixative on radiologically contaminated surfaces. The substances include both generic chemicals and proprietary products. In selecting a fixative for a particular application, several attributes of the fixative may be relevant to the choice. These attributes include: toxicity, durability, and cleanliness and removability. In addition to the attributes of the fixative, one should also take into account certain characteristics of the site to be treated. These characteristics relate to climate, nature of the surface, use to which the treated surface will be put, subsequent cleanup operations, and type of neighboring surfaces. Finally, costs and potential environmental effects may influence the decision. A variety of fixatives are evaluated with respect to these various attributes and summarized in a reference table.

Tawil, J.J.; Bold, F.C.

1983-11-01

218

Positioning and locking apparatus  

DOEpatents

A positioning and locking apparatus including a fixture having a rotatable torque ring provided with a plurality of cam segments for automatically guiding a container into a desired location within the fixture. Rotation of the ring turns the container into a final position in pressure sealing relation against a hatch member.

Hayward, Milton L. (2305 Greenbrook Blvd., Richland, WA 99352); Harper, William H. (1454 Amon Dr., Richland, WA 99352)

1987-01-01

219

Locking Lorentz slides  

Microsoft Academic Search

The purpose of this paper is to introduce the concept of a Locking Lorentz Slide. Lorentz Slide actuators, which are based on the Lorentz force principal of physics and are also called Voice Coils, have earned wide-spread use in the aerospace industry because of their superior performance (precision, force, stroke, wide temperature range including cryogenics, reliability and compactness). NASA has

John M. Vranish; Lawrence M. Germann; Donald R. Lutter; Dale A. Lawrence

1998-01-01

220

Quantum noise locking  

Microsoft Academic Search

Quantum optical states which have no coherent amplitude, such as squeezed vacuum states, cannot rely on standard readout techniques to generate error signals for control of the quadrature phase. Here we investigate the use of asymmetry in the quadrature variances to obtain a phase-sensitive readout and to lock the phase of a squeezed vacuum state, a technique which we call

Kirk McKenzie; Eugeniy E. Mikhailov; Keisuke Goda; Ping Koy Lam; Nicolai Grosse; Malcolm B. Gray; Nergis Mavalvala; David E. McClelland

2005-01-01

221

Pile Driver Hammer Lock.  

National Technical Information Service (NTIS)

Disclosed in the patent application is a safety locking mechanism that prevents a pile driving hammer from accidentally falling while it is in the elevated position on a lead or guide. The device automatically blocks and supports the weight of the hammer ...

W. F. Law L. M. Baez

1974-01-01

222

Rod Lock Mechanism.  

National Technical Information Service (NTIS)

The patent application describes a fluid pressure mechanism for locking a movable rod or similar member in selected positions of adjustment. The mechanism includes a fluid housing having at least one annular rod-gripper element encircling a movable rod. I...

E. F'Geppert

1982-01-01

223

Cable Brake and Lock.  

National Technical Information Service (NTIS)

A cable brake and lock device to control the release of a mooring cable comprises a spring-biased piston abutting an elastic brake element, with the cable passing through both. An initial, preselected force is applied by the spring to the piston and the b...

H. P. Feldman

1976-01-01

224

Positioning and locking apparatus  

DOEpatents

A positioning and locking apparatus including a fixture having a rotatable torque ring provided with a plurality of cam segments for automatically guiding a container into a desired location within the fixture. Rotation of the ring turns the container into a final position in pressure sealing relation against a hatch member.

Hayward, M.L.; Harper, W.H.

1985-06-19

225

Positioning and locking apparatus  

DOEpatents

A positioning and locking apparatus are disclosed including a fixture having a rotatable torque ring provided with a plurality of cam segments for automatically guiding a container into a desired location within the fixture. Rotation of the ring turns the container into a final position in pressure sealing relation against a hatch member. 6 figs.

Hayward, M.L.; Harper, W.H.

1987-06-30

226

Stand-alone anterior lumbar discectomy and fusion with plate: initial experience  

Microsoft Academic Search

BackgroundThe stability of the lumbar spine after ALIF with lateral plate fixation and\\/or posterior fixation has previously been investigated; however, stand-alone ALDF with plate has not. Previous clinical studies have demonstrated poor fusion rates with stand-alone anterior interbody fusion in the absence of posterior instrumentation. We review our initial experience with stand-alone ALDF with segmental plate fixation for degenerative disc

Henry E. Aryan; Daniel C. Lu; Frank L. Acosta; Christopher P. Ames

2007-01-01

227

Internal Fixation for Fractures  

MedlinePLUS

... American Academy of Orthopaedic Surgeons Internal Fixation for Fractures When members of the American Academy of Orthopaedic ... bones together. Can be used alone to treat fractures of small bones, such as those found in ...

228

Lna (Locked Nucleic Acid)  

Microsoft Academic Search

LNA (Locked Nucleic Acid) forms duplexes with complementary DNA, RNA or LNA with unprecedented thermal affinities. CD spectra show that duplexes involving fully modified LNA (especially LNA:RNA) structurally resemble an A-form RNA:RNA duplex. NMR examination of an LNA:DNA duplex confirm the 3?-endo conformation of an LNA monomer. Recognition of double-stranded DNA is demonstrated suggesting strand invasion by LNA. Lipofectin-mediated efficient

Jesper Wengel; Alexei Koshkin; Sanjay K. Singh; Poul Nielsen; Michael Meldgaard; Vivek K. Rajwanshi; Ravindra Kumar; Jan Skouv; Christina B. Nielsen; Jens Peter Jacobsen; Nana Jacobsen; Carl E. Olsen

1999-01-01

229

Rigid versus wire fixation for mandibular advancement: Skeletal and dental changes after 5 years  

Microsoft Academic Search

The bilateral sagittal split osteotomy (BSSO) is the most common surgical procedure for the correction of mandibular retrognathism. Commonly, the proximal and distal segments are fixated together with either wire or rigid screws or plates. The purpose of this study was to compare long-term (5 years) skeletal and dental changes between wire and rigid fixation after BSSO. In this multisite,

Calogero Dolce; John P. Hatch; Joseph E. Van Sickels; John D. Rugh

2002-01-01

230

Locke on Judgement and Religious Toleration  

Microsoft Academic Search

With the publication of Locke’s early manuscripts on toleration and the drafts for the Essay, it is possible to understand to what extent Locke’s ideas on religious toleration have developed. Although the important arguments for toleration can already be found in these early texts, Locke was confronted with a problem in his defence of toleration that he needed to solve.

Maria van der Schaar

2012-01-01

231

Phase locking of relativistic magnetrons  

Microsoft Academic Search

Phase locking of relativistic magnetrons has been achieved at power levels of about 3 GW at 2.8 GHz, exceeding previous phase-locking power levels by 3 orders of magnitude. Two relativistic magnetrons interact directly through a short waveguide of length l about n lambda\\/2 to allow locking. Power-density enhancement due to source coherence is directly measured in the radiation field. Phase

J. Benford; H. Sze; W. Woo; R. R. Smith; B. Harteneck

1989-01-01

232

Safe-haven locking device  

DOEpatents

Disclosed is a locking device for eliminating external control of a secured space formed by fixed and movable barriers. The locking device uses externally and internally controlled locksets and a movable strike, operable from the secured side of the movable barrier, to selectively engage either lockset. A disengagement device, for preventing forces from being applied to the lock bolts is also disclosed. In this manner, a secured space can be controlled from the secured side as a safe-haven. 4 figures.

Williams, J.V.

1984-04-26

233

Treatment of Periprosthetic Femoral Fracture After Cementless Total Hip Arthroplasty With Ilizarov External Fixation  

Microsoft Academic Search

A 72-year-old woman with periprosthetic femoral fracture after cementless total hip arthroplasty (THA) underwent external fixation using the Ilizarov method. Although open reduction and internal fixation with a condylar plate system were initially attempted, deep infection with methicillin-resistant Staphylococcus aureus at the fracture site occurred 2 weeks postoperatively. Six weeks after removal of the plating system, the fracture was stabilized

Takashi Sakai; Kenji Ohzono; Takanobu Nakase; Seung Bak Lee; Tomoya Manaka; Shunsaku Nishihara

2007-01-01

234

Plate position and angular stability: mechanical comparison in sawbone osteotomy models.  

PubMed

Proximal metatarsal osteotomies are inherently unstable and difficult to fix. The purpose of this study was to compare the mechanical stiffness in sawbone models of medially versus dorsally placed plates and then to compare semilocked versus nonlocked plates in different osteotomy configurations. Thirty sawbone models were constructed, fixed either with titanium self-locking or steel mini-fragment plates. They were divided in groups and their stiffness was measured. The stiffness of any model fixed with medial titanium or steel plates was on average 158% and 228% greater, respectively, compared to dorsal plates. Adding a dorsal shelf of bone to a proximal closing wedge osteotomy increases its stiffness. Using locked plates increased the mechanical stiffness in only one configuration. The article suggests that models fixed with medial plates have greater resistance to failure than models fixed with dorsal plates. Using locked plates does not increase the mechanical stiffness of the construct. PMID:24063797

Wagner, Emilio; Ortiz, Cristian; Keller, Andres; Verschae, Gregorio; Wagner, Pablo; Gould, John S

2013-01-01

235

Low complications after minimally invasive fixation of calcaneus fracture  

PubMed Central

Calcaneus fractures are still a delicate point regarding the indication for osteosynthesis. Knowing the skin’s poor vascularisation of the back foot, the purpose of this study is to present the benefits of proper surgical options between an open and invasive osteosynthesis with anatomical reduction and internal fixation or minimally invasive approach preserving the quality of the soft parts. 66 interventions that targeted reduction and internal fixation of calcaneus fractures were performed between 2009-2012, in the Orthopaedic and Traumatology Department of Bucharest Emergency University Hospital. 29 cases underwent open reduction and internal fixation with plates and screws or Kirschner wires, and 37 cases underwent a minimally invasive reduction and Essex Lopresti osteosynthesis technique. No patient who underwent a minimally invasive reduction had skin lesions, but showed pain due to osteoarthritis lesions that appeared in the subtalar joint. 4 of them, who underwent open reduction and internal fixation had postoperative wound infections and skin necrosis.

Ene, R; Popescu, D; Panaitescu, C; Circota, G; Cirstoiu, M; Cirstoiu, C

2013-01-01

236

Locking gas equalizer assembly  

SciTech Connect

This patent describes a method for pumping a fluid with a high gas content with a standing check valve in a standing cage and a traveling check valve in a traveling cage. It comprises: the steps of mechanically unseating the traveling check valve when the traveling cage is at a position nearest the standing cage; mechanically unseating the traveling check valve momentarily as the traveling cage reverses direction at a location furthest from the standing cage; actuating a piston disposed between the traveling cage and the standing valve to axially reciprocate an unseating rod for engaging the traveling check valve; and locking the piston against rotation relative to the traveling cage.

Hebert, D.W.; Harris, E.

1990-03-13

237

Robust Photon Locking  

NASA Astrophysics Data System (ADS)

We experimentally demonstrate a strong-field coherent control mechanism that combines the advantages of photon locking (PL) and rapid adiabatic passage (RAP). Unlike earlier implementations of PL and RAP by pulse sequences or chirped pulses, we use shaped pulses generated by phase modulation of the spectrum of a femtosecond laser pulse with a generalized phase discontinuity. The novel control scenario is characterized by a high degree of robustness achieved via adiabatic preparation of a state of maximum coherence. Subsequent phase control allows for efficient switching among different target states. We investigate both properties by photoelectron spectroscopy on potassium atoms interacting with the intense shaped light field.

Bayer, T.; Wollenhaupt, M.; Sarpe-Tudoran, C.; Baumert, T.

2009-01-01

238

Robust Photon Locking  

SciTech Connect

We experimentally demonstrate a strong-field coherent control mechanism that combines the advantages of photon locking (PL) and rapid adiabatic passage (RAP). Unlike earlier implementations of PL and RAP by pulse sequences or chirped pulses, we use shaped pulses generated by phase modulation of the spectrum of a femtosecond laser pulse with a generalized phase discontinuity. The novel control scenario is characterized by a high degree of robustness achieved via adiabatic preparation of a state of maximum coherence. Subsequent phase control allows for efficient switching among different target states. We investigate both properties by photoelectron spectroscopy on potassium atoms interacting with the intense shaped light field.

Bayer, T.; Wollenhaupt, M.; Sarpe-Tudoran, C.; Baumert, T. [Universitaet Kassel, Institut fuer Physik und CINSaT, Heinrich-Plett-Str. 40, D-34132 Kassel (Germany)

2009-01-16

239

Use of Intraosseous Metal Appliances in Fixation of Mandibular Fractures.  

National Technical Information Service (NTIS)

When it is clinically determined that unfavorable stress might be placed on mandibular fracture segments, use of a transosseous splint or plate may be considered. In this study on dogs, intraosseous use of crossed wire alone for reduction and fixation of ...

E. J. Messer D. E. Hayes P. J. Boyne

1967-01-01

240

49 CFR 236.381 - Traffic locking.  

Code of Federal Regulations, 2012 CFR

...Transportation 4 2012-10-01 2012-10-01 false Traffic locking. 236.381 Section 236.381 Transportation...Interlocking Inspection and Tests § 236.381 Traffic locking. Traffic locking shall be tested when placed in...

2012-10-01

241

49 CFR 236.381 - Traffic locking.  

Code of Federal Regulations, 2011 CFR

...Transportation 4 2011-10-01 2011-10-01 false Traffic locking. 236.381 Section 236.381 Transportation...Interlocking Inspection and Tests § 236.381 Traffic locking. Traffic locking shall be tested when placed in...

2011-10-01

242

49 CFR 236.762 - Locking, indication.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Locking, indication. 236.762 Section 236.762 Transportation Other Regulations Relating to Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.762 Locking, indication. Electric locking which...

2011-10-01

243

Contributions of retinal input and phenomenal representation of a fixation object to the saccadic gap effect.  

PubMed

The saccadic "gap effect" refers to a phenomenon whereby saccadic reaction times (SRTs) are shortened by the removal of a visual fixation stimulus prior to target presentation. In the current study, we investigated whether the gap effect was influenced by retinal input of a fixation stimulus, as well as phenomenal permanence and/or expectation of the re-emergence of a fixation stimulus. In Experiment 1, we used an occluded fixation stimulus that was gradually hidden by a moving plate prior to the target presentation, which produced the impression that the fixation stimulus still remained and would reappear from behind the plate. We found that the gap effect was significantly weakened with the occluded fixation stimulus. However, the SRT with the occluded fixation stimulus was still shorter in comparison to when the fixation stimulus physically remained on the screen. In Experiment 2, we investigated whether this effect was due to phenomenal maintenance or expectation of the reappearance of the fixation stimulus; this was achieved by using occluding plates that were an identical color to the background screen, giving the impression of reappearance of the fixation stimulus but not of its maintenance. The result showed that the gap effect was still weakened by the same degree even without phenomenal maintenance of the fixation stimulus. These results suggest that the saccadic gap effect is modulated by both retinal input and subjective expectation of re-emergence of the fixation stimulus. In addition to oculomotor mechanisms, other components, such as attentional mechanisms, likely contribute to facilitation of the subsequent action. PMID:23438584

Ueda, Hiroshi; Takahashi, Kohske; Watanabe, Katsumi

2013-02-21

244

Transsacral fixation for failed posterior fixation of the pelvic ring  

Microsoft Academic Search

Introduction: In the treatment of certain pelvic ring pathologies (non-unions and failure of ilio-sacral screw fixation) trans-sacral\\u000a fixation (i.e. fixation from iliac wing to the other traversing the body of S1) may be necessary. The purpose of our study\\u000a was to describe our early experience and describe the surgical technique. Materials and methods: Seven cases of trans-sacral fixation were identified

Paul E. Beaulé; John Antoniades; Joel M. Matta

2006-01-01

245

Treatment of midclavicular nonunion: comparison of dynamic compression plating and low-contact dynamic compression plating techniques  

Microsoft Academic Search

In this study a comparison of patients with midclavicular nonunion, treated by a combination of internal fixation with dynamic compression plate (DCP) or low-contact DCP (LC-DCP) and application of autogenous corticocancellous chips or sculptured graft on nonunion areas, was performed. Time to union in the patients treated with LC-DCP fixation was shorter than in those treated with DCP fixation (P

Sevki Kabak; Mehmet Halici; Mehmet Tuncel; Levent Avsarogullari; Sinan Karaoglu

2004-01-01

246

Improving carbon fixation pathways.  

PubMed

A recent resurgence in basic and applied research on photosynthesis has been driven in part by recognition that fulfilling future food and energy requirements will necessitate improvements in crop carbon-fixation efficiencies. Photosynthesis in traditional terrestrial crops is being reexamined in light of molecular strategies employed by photosynthetic microbes to enhance the activity of the Calvin cycle. Synthetic biology is well-situated to provide original approaches for compartmentalizing and enhancing photosynthetic reactions in a species independent manner. Furthermore, the elucidation of alternative carbon-fixation routes distinct from the Calvin cycle raises possibilities that novel pathways and organisms can be utilized to fix atmospheric carbon dioxide into useful materials. PMID:22647231

Ducat, Daniel C; Silver, Pamela A

2012-05-29

247

Improving Carbon Fixation Pathways  

PubMed Central

A recent resurgence in basic and applied research on photosynthesis has been driven in part by recognition that fulfilling future food and energy requirements will necessitate improvements in crop carbon-fixation efficiencies. Photosynthesis in traditional terrestrial crops is being reexamined in light of molecular strategies employed by photosynthetic microbes to enhance the activity of the Calvin cycle. Synthetic biology is well-situated to provide original approaches for compartmentalizing and enhancing photosynthetic reactions in a species independent manner. Furthermore, the elucidation of alternative carbon-fixation routes distinct from the Calvin cycle raises possibilities that alternative pathways and organisms can be utilized to fix atmospheric carbon dioxide into useful materials.

Ducat, Daniel C.

2012-01-01

248

Frequency and Phase Lock Loop  

Microsoft Academic Search

A new electronic subsystem has been developed: The frequency and phase lock loop. It has an extended acquisition range compared to the standard phase lock loop. It will be advantageous to use this new loop in all applications where a simultaneous need for large acquisition range and a narrow tracking bandwidth can justify the added complexity of the new loop.

Richard Citta

1977-01-01

249

Fixative for fixing biological materials  

US Patent & Trademark Office Database

A fixative for fixing biological materials contains a depot agent, preferably a polyamine and especially hexamethylenetetramine, which reacts chemically with positively charged ions, especially H+ from an acid, while forming a fixative, where the fixative is an aldehyde and especially formaldehyde, which in turn reacts chemically with the biological material to be fixed in order to fix it and is consumed in doing so. By adjusting the pH of a solution containing the depot agent, a chemical equilibrium reaction occurs between the depot agent, fixative and biological material, so that just as much fixative is continuously formed as can be immediately consumed by the biological material. With that, the fixative, and especially the hazardous formaldehyde, cannot escape. Thus, an externally formaldehyde-free fixative that at the same time has the excellent fixative properties of formaldehyde is created.

Szabados; Andreas (Grunwald, DE); Gerigk; Roberto (Muhldorf a. Inn, DE)

2011-03-29

250

The Fixation of Nitrogen.  

ERIC Educational Resources Information Center

|Discusses the fixation of atmospheric nitrogen in the form of ammonia as one of the foundations of modern chemical industry. The article describes ammonia production and synthesis, purifying the hydrogen-nitrogen mix, nitric acid production, and its commericial plant. (HM)|

Andrew, S. P. S.

1978-01-01

251

Carbon dioxide fixation.  

National Technical Information Service (NTIS)

Solar carbon dioxide fixation offers the possibility of a renewable source of chemicals and fuels in the future. Its realization rests on future advances in the efficiency of solar energy collection and development of suitable catalysts for CO(sub 2) conv...

E. Fujita

2000-01-01

252

Nitrogen Fixation by Gloeocapsa  

Microsoft Academic Search

The continuous growth in a medium free of combined nitrogen and the experimental production of ethylene via acetylene reduction indicate that nitrogen fixation by blue-green algae is not solely confined to filamentous genera with heterocysts. Axenic cultures of Gloeocapsa sp., adapted to nitrate-free medium, form ethylene at rates comparable to those of species known to fix nitrogen.

J. T. Wyatt; J. K. G. Silvey

1969-01-01

253

Translaminar Facet Screw Fixation  

Microsoft Academic Search

significantly longer than that used by both Boucher and King due to an entry point at the base of the contralateral spinous process. This improves the technique by increasing the ef- fective working length of the screw on both sides of the facet joint resulting in increased strength of the fixation. This review focuses on the advantages of translaminar facet

Rick C. Sasso; Natalie M. Best

254

49 CFR 236.766 - Locking, movable bridge.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Locking, movable bridge. 236.766 Section 236.766 Transportation... Definitions § 236.766 Locking, movable bridge. The rail locks, bridge locks, bolt locks, circuit controllers,...

2012-10-01

255

49 CFR 236.766 - Locking, movable bridge.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Locking, movable bridge. 236.766 Section 236.766 Transportation... Definitions § 236.766 Locking, movable bridge. The rail locks, bridge locks, bolt locks, circuit controllers,...

2011-10-01

256

Plate motion  

SciTech Connect

The motion of tectonic plates on the earth is characterized in a critical review of U.S. research from the period 1987-1990. Topics addressed include the NUVEL-1 global model of current plate motions, diffuse plate boundaries and the oceanic lithosphere, the relation between plate motions and distributed deformations, accelerations and the steadiness of plate motions, the distribution of current Pacific-North America motion across western North America and its margin, plate reconstructions and their uncertainties, hotspots, and plate dynamics. A comprehensive bibliography is provided. 126 refs.

Gordon, R.G. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

1991-01-01

257

Single-bone fixation of paediatric diaphyseal both-bone forearm fractures: a systematic review.  

PubMed

Unstable paediatric diaphyseal both-bone forearm fractures that fail conservative management are usually treated with fixation of both radius and ulna. This systematic review aimed to establish if single-bone fixation achieves results comparable to both-bone fixation and which bone should be fixed and by what method. A systematic review of the published literature was performed, searching Medline for English language studies that reported functional or radiographic outcome following single-bone fixation of either bone by any method. Eight studies met the inclusion criteria (Level of Evidence III or IV). Three studies compared single- with both-bone fixation, showing comparable functional and radiographic outcomes. Redisplacement of the radius fracture is common following fixation of the ulna, particularly with intramedullary K-wires. Flexible nails achieve better results than K-wires in intramedullary stabilisations. Outcome is good following radius fixation with plating or nailing. Plating achieves good results in either bone. Few complications are seen when the second bone was left unfixed only if reduced and stable. Single-bone fixation achieves results comparable to both-bone fixation. Fixing the radius rather than the ulna provides better outcome, regardless of the method. The second bone should only be left unfixed if reduced and stable intra-operatively. PMID:23019772

Westacott, Daniel; Dickenson, Edward; Smith, Nicholas

2012-08-01

258

Sternal salvage with rigid fixation in the setting of a massive mediastinal aortic pseudoaneurysm: a case report and review of the literature.  

PubMed

Reconstruction of sternal nonunion following surgical resection can be difficult. Presented here is a case of sternal salvage with rigid fixation in the face of a massive aortic pseudoaneurysm. Plating is a safe and efficient technique that provides bone approximation and results in long term rigid sternal fixation. This case report highlights the history and biomechanical theory and examines the safety and clinical outcomes of sternal reconstruction with plating fixation. PMID:18033747

Shifrin, David A; Sohn, Samuel M; Stouffer, Chadwick W; Hooker, Robert L; Renucci, John D

2007-11-26

259

Phase-Locked Loops  

NSDL National Science Digital Library

Phase-locked loops (PLL) are unique feedback control circuits that offer many useful features and benefits in electronic applications. PLLs are available either in integrated circuit (IC) form for general applications or built into larger system IC chips. Today, PLLs are found in virtually all types of electronic equipment from PCs to consumer products like TV sets and cell phones. This module provides an introduction to the PLL and its applications. It begins with an overview of the main components of a PLL and how these components work together. It then describes PLL specifications and a description of the most widely used applications including frequency synthesizers, clock multipliers, clock and data recovery circuits, FM demodulators, and filters.

2012-09-06

260

Plate Tectonics  

NSDL National Science Digital Library

Students will go over the main points of plate tectonics, including the theory of continental drift, different types of plate boundaries, seafloor spreading, and convection currents. We have been spending time learning about plate tectonics. We have discussed the theory of continental drift, we have talked about the different types of plate boundaries, we have also learned about seafloor spreading and convection currents. Plate Boundary Diagram Now is your chance ...

Rohlfing, Mrs.

2011-02-03

261

Biomechanical comparison of gourd-shaped LCP versus LCP for fixation of comminuted tibial shaft fracture.  

PubMed

The purpose of this study was to compare monotonic biomechanical properties of gourd-shaped LCP fixation with LCP fixation of human tibial shaft in gap fracture mode. Twenty paired fresh cadaveric human tibias were randomly divided into 4 groups (5 pairs each): (1) axial loading single cycle to failure testing, (2) torsion single cycle to failure testing, (3) 4-point bending single cycle to failure testing, and (4) dynamic 4-point bending testing. A 7-hole 4.5 mm gourd-shaped LCP was secured on the anteromedial surface of 1 randomly selected bone from each pair, respectively, using 6 locking screws in the 1st, 2nd, 3rd, 5th, 6th and 7th hole with the middle hole unfilled and just located at the mid-diaphysis of the tibia. A 7-hole 4.5 mm LCP was secured on the other bone with the same method. Standard AO/ASIF techniques were used. After fixation finished, a 10 mm gap in the mid-diaphysis of tibia was created, centrally located at the unfilled hole. The axial, torsional, and bending stiffness and failure strengths were calculated from the collected data in static testings and statistically compared using paired Student's t-test. The 4-point bending fatigue lives of the two constructs were calculated from the dynamic testing data and also statistically compared using paired Student's t-test. Failure modes were recorded and visually analyzed. P<0.05 was considered significant. Results showed that the axial, torsional and bending stiffness of gourd-shaped LCP construct was greater (4%, 19%, 12%, respectively, P<0.05) than that of the LCP construct, and the axial, torsional and bending failure strengths of gourd-shaped LCP construct were stronger (10%, 46%, 29%, respectively, P<0.05) than those of the LCP construct. Both constructs failed as a result of plate plastic torsional deformation. After axial loading and 4-point bending testings, LCP failed in term of an obvious deformation of bent apex just at the unfilled plate hole, while the gourd-shaped LCP failed in term of a deformation of bent arc between the 3rd and 5th holes, which indicated a more consistent stress distribution on gourd-shaped LCP. Fatigue life of gourd-shaped LCP construct was significantly greater than LCP construct (153 836±2 228 vs. 132 471±6 460 cycles, P<0.01). All constructs failed as a result of fracture of the plate through the compression hole of the unfilled combination screw hole. The biomechanical testing showed that gourd-shaped LCP can provide greater stiffness and strength, and longer fatigue life than LCP. The gourd-shaped LCP may be more advantageous mechanically and may reduce the plate breakage rate clinically. PMID:23592139

Xu, Guo-hui; Liu, Bo; Zhang, Qi; Wang, Juan; Chen, Wei; Liu, Yue-ju; Peng, A-qin; Zhang, Ying-ze

2013-04-17

262

The Mechanics of External Fixation  

PubMed Central

External fixation has evolved from being used primarily as a last resort fixation method to becoming a main stream technique used to treat a myriad of bone and soft tissue pathologies. Techniques in limb reconstruction continue to advance largely as a result of the use of these external devices. A thorough understanding of the biomechanical principles of external fixation is useful for all orthopedic surgeons as most will have to occasionally mount a fixator throughout their career. In this review, various types of external fixators and their common clinical applications are described with a focus on unilateral and circular frames. The biomechanical principles that govern bony and fixator stability are reviewed as well as the recommended techniques for applying external fixators to maximize stability. Additionally, we have illustrated methods for managing patients while they are in the external frames to facilitate function and shorten treatment duration.

Rozbruch, S. Robert

2006-01-01

263

Plate Boundaries  

NSDL National Science Digital Library

This site provides information on plate boundaries, which are found at the edge of the lithospheric plates and are of three types: convergent, divergent and conservative. Wide zones of deformation are usually characteristic of plate boundaries because of the interaction between two plates. The three boundaries are characterized by their distinct motions which are described in the text and depicted with block diagram illustrations, all of which are animated. There are also two maps that show the direction of motion of the plates. Active links lead to more information on plate tectonics.

264

Cavity-locked ring down spectroscopy  

DOEpatents

Distinct locking and sampling light beams are used in a cavity ring-down spectroscopy (CRDS) system to perform multiple ring-down measurements while the laser and ring-down cavity are continuously locked. The sampling and locking light beams have different frequencies, to ensure that the sampling and locking light are decoupled within the cavity. Preferably, the ring-down cavity is ring-shaped, the sampling light is s-polarized, and the locking light is p-polarized. Transmitted sampling light is used for ring-down measurements, while reflected locking light is used for locking in a Pound-Drever scheme.

Zare, Richard N. (Stanford, CA); Paldus, Barbara A. (Stanford, CA); Harb, Charles C. (Palo Alto, CA); Spence, Thomas (Union City, CA)

2000-01-01

265

Cavity-locked ring down spectroscopy  

SciTech Connect

Distinct locking and sampling light beams are used in a cavity ring-down spectroscopy (CRDS) system to perform multiple ring-down measurements while the laser and ring-down cavity are continuously locked. The sampling and locking light beams have different frequencies, to ensure that the sampling and locking light are decoupled within the cavity. Preferably, the ring-down cavity is ring-shaped, the sampling light is s-polarized, and the locking light is p-polarized. Transmitted sampling light is used for ring-down measurements, while reflected locking light is used for locking in a Pound-Drever scheme.

Zare, R.N.; Paldus, B.A.; Harb, C.C.; Spence, T.

2000-07-04

266

[Locked intramedullary nailing in treatment of femur and tibia delayed union and pseudoarthrosis].  

PubMed

Five patients treated operatively on account of tibia and femur shaft delayed union and pseudoarthrosis were re-operated by locked intramedullary nailing. The method permits stable bone fixation. Intramedullary canal reaming stimulates bone union, as it refreshes fracture site and is a source of bone graft. Intramedullary nail covers anatomical axis of bone and, in the case of femur, is close to its mechanical axis. It diminishes the risk of implant breakage. The method permits active and efficient rehabilitation. Some fractures stabilised with external fixator or operated by Zespol or Polfix method can be re-operated by close technic. It shortens time of operation and diminishes its aggressiveness. In our opinion locked intramedullary nailing is an efficient method in treatment of tibia and femur shaft delayed union and pseudoarthrosis. PMID:15307378

Wójcik, Krzysztof; Ga?dzik, Tadeusz Szymon; Jaworski, Jerzy Miros?aw; Gajda, Tomasz

2004-01-01

267

75 FR 5071 - Lock + TM  

Federal Register 2010, 2011, 2012, 2013

...estimated average annual generation of about 62,130 megawatts-hours. Lock + Hydro Contact: Wayne F. Krouse, Chairman and CEO, Hydro Green Energy, LLC., 5090 Richmond Avenue, Suite 290, Houston, TX 77056, (877) 556-6566. FERC...

2010-02-01

268

75 FR 5068 - Lock + TM  

Federal Register 2010, 2011, 2012, 2013

...estimated average annual generation of about 62,130 megawatts-hours. Lock + Hydro Contact: Wayne F. Krouse, Chairman and CEO, Hydro Green Energy, LLC., 5090 Richmond Avenue, Suite 290, Houston, TX 77056, (877) 556-6566. FERC...

2010-02-01

269

Locking Mechanism for Orthopedic Braces.  

National Technical Information Service (NTIS)

A locking mechanism for orthopedic braces is described which automatically prevents or permits the relative pivotable movement between a lower brace member and an upper brace member. The upper and lower brace members are provided with drilled bores within...

J. I-lechao C. H. Epps

1976-01-01

270

Biology Nitrogen Fixation: Fundamentals  

Microsoft Academic Search

The enzyme responsible for N_2 fixation, nitrogenase, is only found in prokaryotes. It consists of two metalloproteins, both irreversibly destroyed by exposure to the O_2 of air. The MoFe-protein binds N_2 and the Fe-protein, after activation by MgATP, supplies electrons. H_2 is evolved during the reduction of N_2 to NH_3 and can become the sole reaction in the absence of

J. R. Postgate

1982-01-01

271

Color-Flavor Locked Strangelets  

Microsoft Academic Search

Finite lumps of color-flavor locked strange-quark matter (CFL strangelets) are significantly more stable than strangelets without color-flavor locking for wide ranges of parameters, increasing the likelihood of strangelet metastability, or even absolute stability beyond some minimum baryon number Amin. Whereas bulk CFL strange-quark matter is electrically neutral, CFL strangelets are positively charged, with Z~0.3A2\\/3. This is quite different from ``ordinary''

Jes Madsen

2001-01-01

272

Surgeon Perception of Cancellous Screw Fixation.  

PubMed

OBJECTIVES:: The ability of surgeons to optimize screw insertion torque in nonlocking fixation constructs is important for stability, particularly in osteoporotic and cancellous bone. This study evaluated screw torque applied by surgeons during synthetic cancellous fixation. It evaluated the frequency that screws were stripped by the surgeon, factors associated with screw stripping, and the ability of surgeons to recognize it. METHODS:: Ten surgeons assembled screw and plate fixation constructs into three densities of synthetic cancellous bone while screw insertion torque and axial force were measured. For each screw, the surgeon recorded a subjective rating as to whether or not the screw had been stripped. Screws were then advanced past stripping and stripped screws were identified by comparing the insertion torque applied by the surgeon to the measured stripping torque. RESULTS:: Surgeons stripped 109 of 240 screws (45.4%) and did not recognize stripping 90.8% of the time that it occurred. The tendency to strip screws was highly variable among individual surgeons (ranging from 16.7% to 83.3% stripped, p < 0.0001) and did not correlate to synthetic bone density in the range tested (p = 0.186), nor to rank as resident or attending surgeon (p = 0.437). Screws that were correctly recognized as stripped retained a mean 55.0% of maximum torque, less than when stripping was not recognized (79.6%, p = 0.005). CONCLUSIONS:: Surgeon perception is not reliable at preventing and detecting screw stripping at clinical torque levels in synthetic cancellous bone. Less aggressive insertion or standardized methods of insertion may improve the stability of nonlocking screw and plate constructs. PMID:23782959

Stoesz, Michael J; Gustafson, Peter A; Patel, Bipinchandra; Jastifer, James R; Chess, Joseph L

2013-06-18

273

Plate Tectonics  

NSDL National Science Digital Library

In this activity students use data from underwater earthquakes to outline the location of plate boundaries. Data from the Northeast Pacific, eastern Equatorial Pacific, and North Atlantic are examined in more detail. Background information on plate tectonics is provided.

2002-01-01

274

FES Fine Lock Guidance Test  

NASA Astrophysics Data System (ADS)

The current operational limit for fine lock is 13.0 magnitude, rather than the planned 14.5 magnitude. This restriction is due to the OTA spherical aberration and internal FGS effects. The limitation severly restricts the availability of guide stars for observations which require fine lock for guidance. The purpose of this test is to determine whether use of FES averaging time can allow the capture and guidance on stars fainter than 13.0, thus recovering the lost capability. This test will verify that fine lock averaging with NULL-BYPASS can be used to support pointing control. The discussions with the flight software engineers suggests that the FGS can be run with fine lock averaging as large as 100 milli-seconds without compromising the pointing control system. The probability of lock and the stability while in lock needs to be verified using the Spacecraft with an observation which is not scientifically critical before this method of guidance is used to support scientific observations.

Schiffer, Francis

1990-07-01

275

High-Performance, Space-Efficient, Automated Object Locking  

Microsoft Academic Search

The paper studies the impact of several lock manager de- signs on the overhead imposed to a persistent programming language by automated object locking. Our study reveals that a lock management method based onlock state shar- ing outperforms more traditional lock management designs. Lock state sharing is a novel lock management method that represents all lock data structures with equal

Laurent Daynès; Grzegorz Czajkowski

2001-01-01

276

Plate Tectonics  

NSDL National Science Digital Library

This interactive Flash explores plate tectonics and provides an interactive map where users can identify plate boundaries with name and velocities as well as locations of earthquakes, volcanoes, and hotspots. The site also provides animations and supplementary information about plate movement and subduction. This resource is a helpful overview or review for introductory level high school or undergraduate physical geology or Earth science students.

Smoothstone; Company, Houghton M.

277

Plate Tectonics  

NSDL National Science Digital Library

Create a poster all about Plate Tectonics! Directions: Make a poster about Plate Tectonics. (20 points) Include at least (1) large picture (15 points) on your poster complete with labels of every part (10 points). (15 points) Include at least three (3) facts about Plate Tectonics. (5 points ...

Walls, Mrs.

2011-01-30

278

Temporal stimulus properties that attract gaze to the periphery and repel gaze from fixation.  

PubMed

Humans use saccadic eye movements to fixate different parts of their visual environment. While stimulus features that determine the location of the next fixation in static images have been extensively studied, temporal stimulus features that determine the timing of the gaze shifts received less attention. It is also unclear if stimulus features at the present gaze location can trigger gaze shifts to another location. To investigate these questions, we asked observers to switch their gaze between two blobs. In three different conditions, either the fixated blob, the peripheral blob, or both blobs were flickering. A time-frequency analysis of the flickering noise values, time locked to the gaze shifts, revealed significant phase locking in a time window 300 to 100 ms before the gaze shift at temporal frequencies below 20 Hz. The average phase angles at these time-frequency points indicated that observer's gaze was repelled by decreasing contrast of the fixated blob and attracted by increasing contrast of the peripheral blob. These results show that temporal properties of both, fixated, and peripheral stimuli are capable of triggering gaze shifts. PMID:23568849

Schütz, Alexander C; Lossin, Felix; Kerzel, Dirk

2013-04-08

279

Locked intramedullary nailing of humeral shaft fractures. Implant design, surgical technique, and clinical results.  

PubMed

We report our experience with a modified implant and a new technique for locked intramedullary nailing of the humerus in 41 patients. Locking was by cross-screws placed from lateral to medial in the proximal humerus, and anteroposteriorly in the distal humerus. Early in the series, 11 nails were inserted at the shoulder, but we found that rehabilitation was faster after retrograde nailing through the olecranon fossa, which was used for the other 30. We used a closed technique for 29 of the nailings. Of the 41 patients treated, 21 had acute fractures, five had nonunion, and 15 had pathological fractures. Secure fixation was obtained for comminuted and osteoporotic fractures in any part of the humeral shaft, which allowed the early use of crutches and walking frames. Two nails were locked at only one end, and one of these became the only failure of union after an acute fracture. PMID:8300675

Ingman, A M; Waters, D A

1994-01-01

280

Plate Tectonics  

NSDL National Science Digital Library

The Plate Tectonics SciPack explores the various materials that make up Earth and the processes they undergo to provide a framework for understanding how continents are created and change over time. The focus is on Standards and Benchmarks related to Earth's layers, oceanic and continental plates and the interactions between plates.In addition to comprehensive inquiry-based learning materials tied to Science Education Standards and Benchmarks, the SciPack includes the following additional components:� Pedagogical Implications section addressing common misconceptions, teaching resources and strand maps linking grade band appropriate content to standards. � Access to one-on-one support via e-mail to content "Wizards".� Final Assessment which can be used to certify mastery of the concepts.Learning Outcomes:Plate Tectonics: Layered Earth� Identify that Earth has layers (not necessarily name them), and that the interior is hotter and more dense than the crust.� Identify the crust as mechanically strong, and the underlying mantle as deformable and convecting.Plate Tectonics: Plates� Identify that the outermost layer of Earth is made up of separate plates.� Choose the correct speed of the motion of plates.� Identify the ocean floor as plate, in addition to the continents (to combat the common idea that only continents are plates, floating around on the oceans).� Recognize that oceans and continents can coexist on the same plate.Plate Tectonics: Plate Interactions� Identify the different interactions between plates.� Discuss what happens as a result of those interactions.Plate Tectonics: Consequences of Plate Interactions� Explain why volcanoes and earthquakes occur along plate boundaries. � Explain how new sea floor is created and destroyed.� Describe features that may be seen on the surface as a result of plate interactions.Plate Tectonics: Lines of Evidence� Use plate tectonics to explain changes in continents and their positions over geologic time.� Provide evidence for the idea of plates, including the location of earthquakes and volcanoes, continental drift, magnetic orientation of rocks in the ocean floor, etc.

National Science Teachers Association (NSTA)

2007-03-21

281

Investigation of metallic and carbon fibre PEEK fracture fixation devices for three-part proximal humeral fractures.  

PubMed

A computational investigation of proximal humeral fracture fixation has been conducted. Four devices were selected for the study; a locking plate, intramedullary nail (IM Nail), K-wires and a Bilboquet device. A 3D model of a humerus was created using a process of thresholding based on the grayscale values of a CT scan of an intact humerus. An idealised three part fracture was created in addition to removing a standard volume from the humeral head as a representation of bone voids that occur as a result of the injury. All finite element simulations conducted represent 90° arm abduction. Simulations were conducted to investigate the effect of filling this bone void with calcium phosphate cement for each device. The effect of constructing devices from carbon fibre polyetheretherketone (CFPEEK) was investigated. Simulations of cement reinforced devices predict greater stability for each device. The average unreinforced fracture line opening (FLO) is reduced by 48.5% for metallic devices with a lesser effect on composite devices with FLO reduced by 23.6%. Relative sliding (shear displacement) is also reduced between fracture fragments by an average of 58.34%. CFPEEK device simulations predict reduced stresses at the device-bone interface. PMID:22989528

Feerick, Emer M; Kennedy, Jim; Mullett, Hannan; FitzPatrick, David; McGarry, Patrick

2012-09-16

282

Forefoot applications of external fixation.  

PubMed

The use of external fixation in foot and ankle surgery has steadily increased with the advent of devices geared toward the foot and ankle that have evolved over the past decade, as well as a greater understanding of the indications and advantages of external fixation. The application of external fixators in the forefoot may at first glance seem both limited and possibly overkill, but once the basics of external fixation and the types of devices available are understood the options for use become numerous. PMID:12613075

DeHeer, Patrick A

2003-01-01

283

A biomechanical study comparing cortical onlay allograft struts and plates in the treatment of periprosthetic femoral fractures  

Microsoft Academic Search

Background: Periprosthetic femoral fractures with well-fixed femoral components can be difficult to manage and internal fixation is usually necessary. This study was designed to determine the effect of cable plate, strut allograft and combined plate and strut allograft fixations of periprosthetic femoral fractures.Methods: A transverse fracture at the level of the tip of the femoral stem was simulated in six

Darrin Wilson; Hanspeter Frei; Bassam A. Masri; Thomas R. Oxland; Clive P. Duncan

2005-01-01

284

Suitability of DCPs with screw locking elements to allow sufficient interfragmentary motion to promote secondary bone healing of osteoporotic fractures.  

PubMed

This paper analyses the suitability of a system comprising a Dynamic Compression Plate (DCP) and Screw Locking Elements (SLEs) to allow sufficient interfragmentary motion to promote secondary bone healing in osteoporotic fractures. Four fixation systems were mounted on bone-simulating reinforced epoxy bars filled with solid rigid polyurethane foam. Group 1, used for comparison purposes, represents a system comprised of a Locking Compression Plate (LCP) and eight locking screws. Groups 2 and 3 represent a system comprised of a DCP plate with eight cortical screws and two SLEs placed on the screws furthest from (group 2) and nearest to (group 3) the fracture. Group 4 represents the system comprised of a DCP plate with SLEs placed on all eight cortical screws. Cyclic compression tests of up to 10,000 load cycles were performed in order to determine the parameters of interest, namely the stiffnesses and the interfragmentary motion of the various configurations under consideration. Tukey's multiple comparison test was used to analyse the existence or otherwise of significant differences between the means of the groups. At 10,000 cycles, interfragmentary motion at the far cortex for group 2 was 0.60±0.04 mm and for group 3 0.59±0.03 mm (there being no significant differences: p=0.995). The mean interfragmentary motion at the far cortex of the LCP construct was 70% less than that of the two groups with 2SLEs (there being significant differences: p=1.1×10(-8)). In the case of group 4 this figure was 45% less than in groups 2 and 3 (there being significant differences: p=5.6×10(-6)). At 10,000 cycles, interfragmentary motion at the near cortex for group 2 was 0.24±0.06 mm and for group 3 0.24±0.03 mm (there being no significant differences: p=1.000). The mean interfragmentary motion at the near cortex of the LCP construct was 70.8% less than that of the two groups with 2SLEs (there being significant differences: p=0.011). In the case of group 4 this figure was 66.7% less than in groups 2 and 3 (there being significant differences: p=0.016). The mean stiffness at 10,000 cycles was 960±110 N mm(-1) for group 2 and 969±53 N mm(-1) for group 3 (there being no significant differences: p=1.000). For group 1 (the LCP construct) the mean stiffness at 10,000 cycles was 3144±446 N mm(-1), 3.25 times higher than that of groups 2 and 3 (there being significant differences: p=0.00002), and 1.6 times higher than that of the DCP+8SLEs construct (1944±408 N mm(-1), there being significant differences: p=0.007). It is concluded that using the DCP+2SLEs construct sufficient interfragmentary motion is ensured to promote secondary bone healing. However, if too many SLEs are used the result may be, as with the LCP, an excessively rigid system for callus formation. PMID:22998895

Cuadrado, A; Yánez, A; Carta, J A; Garcés, G

2012-09-19

285

Plate subrotations  

NASA Astrophysics Data System (ADS)

The kinematics of plates is defined by Euler pole and angular velocity. However, during their journey, plates may be affected by additional simultaneous rotations (i.e., subrotations) while they are rotating about their Euler poles. The kinematic description of this particular plate motion requires a different analytical approach: two angular velocities and two poles are necessary to completely describe plate displacements. If a subrotation occurs, none of the points on a plate moves along circles of the Euler pole but, instead, follows cycloid trajectories because of the combination of the two simultaneous rotations. Regardless of the forces that move the lithosphere, every time a plate experiences a subrotation, an additional force (or resisting) force could act on the plate, generating the two-rotation motion. In the hot spot reference frame, we applied this model to the North America plate, investigating its past motion for a time interval ?t = 43 Ma up to the present and comparing results with those obtained by Gordon and Jurdy (1986). This application shows how the different positions of the North America plate over most of the Cenozoic can be reconstructed by two-rotation plate kinematics.

Cuffaro, Marco; Caputo, Michele; Doglioni, Carlo

2008-08-01

286

Definitive Bone Fixation and Reconstruction: Conversion from Temporary External Fixation to Internal Fixation Methods  

Microsoft Academic Search

\\u000a Temporary external fixation is frequently employed in the military combat theater of operations to temporize devastating extremity\\u000a injuries and facilitate transport of the wounded soldier. Multiple civilian and a few military studies have provided helpful\\u000a insight into the staged treatment of these injuries including conversion of temporary external fixation to definitive stabilization\\u000a with internal fixation. Diaphyseal fractures of the long

Craig S. Bartlett; Benjamin Geer; David L. Helfet

287

Prophylactic internal fixation of the radial osteocutaneous donor site.  

PubMed

The technique of prophylactic internal fixation (PIF) of the radial osteocutaneous donor site is described and reviewed. Twenty-two donor sites were reinforced with a 3.5mm dynamic compression plate across the anterior defect. The incidence of fracture was 4.5% (1 out of 22). The single fracture was due to a technical error and was managed conservatively. Fracture at a donor site that has not been plated is more frequent and often becomes displaced, requiring secondary surgery. In contrast, the incidence of fracture, displacement and secondary surgery following prophylactic internal fixation (PIF) is relatively low. There have been no significant long-term complications with PIF. It is now the method of choice for managing the radial osteocutaneous donor site. PMID:17110005

Avery, C M E; Danford, M; Johnson, P A

2006-11-15

288

Efficacy of two point rigid internal fixation in the management of zygomatic complex fracture  

Microsoft Academic Search

Purpose  To evaluate the efficacy of two point rigid internal fixation in the immobilization of zygomatic complex fractures.\\u000a \\u000a \\u000a \\u000a Patients and methods  30 patients with zygomatic complex fractures were managed by open reduction and internal fixation using titanium mini bone\\u000a plate screws at the frontozygomatic and zygomatic buttress region. This prospective study was carried out at the Department\\u000a of Oral & Maxillofacial Surgery,

Ashish Chakranarayan; G. K. Thapliyal; R. Sinha; Menon P. Suresh

2009-01-01

289

Fluid distribution in the subducting plate influences interplate slip  

NASA Astrophysics Data System (ADS)

We integrate geodetic and seismological data to explore the mechanisms controlling plate-locking degree, coseismic slip and afterslip distributions at the southern end of the 2010 Maule earthquake (Mw 8.8) rupture zone. We derive from a high-resolution seismic tomography the major lateral variations of the Vp/Vs ratio around the plate interface before the Maule earthquake. This ratio is correlated to changes of the Poisson's ratio which is a proxy for fluids. We demonstrate that the locking degree during the interseismic phase is closely related to the Poisson's ratio variations and thus to lateral variations of fluid content. Locking degree and Poisson's ratio are correlated, as shown by high locked patches in areas of lower Poisson's ratio suggesting that high accumulation of seismic energy relates to areas with low fluid content. In turn, areas with low locking degree and high afterslip rates correlate with enhanced Poisson's ratio, showing the influence of fluids. The inhomogeneous fluid content along strike is due to the Mocha fracture zone that is subducted in the southern part of the Maule rupture plane. Here dehydration due to methamorphic reactions provide substantial fluid volumes that migrate along the fractures into the subduction interface whereas further north of the fracture zone much less fluid is available causing a high locking degree and high co-seismic slip. Our findings suggest that the variation of fluid content and thus changes of effective stress at the plate interface have a direct control in the interplate dynamics.

Moreno, Marcos; Haberland, Christian; Oncken, Onno; Rietbrock, Andreas; Angiboust, Samuel; Heidbach, Oliver

2013-04-01

290

78. LOCKS CULVERT TAINTER VALVE CHAMBERS EAST AND ...  

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

78. LOCKS -- CULVERT TAINTER VALVE CHAMBERS -- EAST AND INTERMEDIATE WALLS -- MAIN LOCK M-L 27 20/33. Lock and Dam No. 27 - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 27, Granite City, Madison County, IL

291

DINITROGEN FIXATION IN ILLINOIS BUNDLEFLOWER  

Technology Transfer Automated Retrieval System (TEKTRAN)

Illinois bundleflower [Desmanthus illinoensis (Michx.) MacMillan] is a warm-season perennial forage legume that may serve as a pulse crop. Its productivity is influenced by its N2 fixation capability. Our objective was to estimate symbiotic N2 fixation of three Illinois bundleflower accessions from ...

292

Locked-wrap fuel rod  

DOEpatents

A method for spacing fast reactor fuel rods using a wire wrapper improved by orienting the wire-wrapped fuel rods in a unique manner which introduces desirable performance characteristics not attainable by previous wire-wrapped designs. Use of this method in a liquid metal fast breeder reactor results in: (a) improved mechanical performance, (b) improved rod-to-rod contact, (c) reduced steel volume, and (d) improved thermal-hydraulic performance. The method produces a "locked wrap" design which tends to lock the rods together at each of the wire cluster locations.

Kaplan, Samuel (Los Gatos, CA); Chertock, Alan J. (San Francisco, CA); Punches, James R. (San Jose, CA)

1977-01-01

293

Operative treatment for volar plate avulsion fractures of the fingers.  

PubMed

We present our experience with 14 volar plate avulsion fractures of the fingers that were treated by excision or internal fixation and discuss the factors affecting the operative techniques and results. Fourteen cases were divided into two groups: the volar plate avulsions with excision (eight cases) and the volar plate avulsions with fixation (six). We compared clinical factors between fracture groups and between fixation methods. Fractures treated with fixation had the larger fragment, a shorter preoperative period, and the larger articular surface involvement than fractures treated with excision. Postoperative pain, average age, patients' satisfaction measured by VAS, DASH scores, grip, and pinch strength were not different between two groups. All fixated fractures healed and the time to union did not differ based on fixation method. The true size of the fracture fragment was larger than expected based on the X-ray and the fragments were usually rotated by pull of the volar plate or ligament. The size and shape of the avulsed fragment might be important factors to determine the treatment method, but the results after operation were not significantly different whether the fragment was excised or fixed. PMID:23892555

Lee, Sanglim; Jung, Eui Yub; Kim, Ji Yeong

2013-07-28

294

Fracture risk and initial fixation of a cementless glenoid implant: The effect of numbers and types of screws.  

PubMed

The initial fixation of an anatomical cementless glenoid component, provided by different numbers and types of screws, and the risk of bone fracture were evaluated by estimating the bone-implant interface micromotions and the principal strains around the prosthesis. Four different fixation configurations using locking or compression screws were tested. Estimation of the micromotions at the bone-implant interface was performed both experimentally, using an in vitro model, and computationally, using a numerical model. Principal bone strains were estimated using the numerical model. Subject variability was included by modelling two different bone qualities (healthy and rheumatoid bone). For the fixation configurations that used two screws, experimental and modelling results found that the micromotions at the bone-implant interface did not change with screw type. However, screw type had a significant effect on fixation when only one screw was used; in this case, a locking screw resulted in less micromotion at the bone-implant interface compared with the compression screw. Bone strains were predicted by the numerical model, and strains were found to be independent of the screw type; however, the predicted strain levels calculated in rheumatoid bone were larger than the strain levels that may cause bone damage for most considered arm positions. Predicted bone strain in healthy bone did not reach this level. While proper initial component fixation that allows biological fixation can be achieved by using additional screws, the risk of bone failure around the screws must be considered, especially in cases of weak bone. PMID:23804951

Suarez, Daniel R; Valstar, Edward R; Rozing, Piet M; van Keulen, Fred

2013-06-26

295

Barkley Lock Prototype Tests, Cumberland River, Kentucky.  

National Technical Information Service (NTIS)

This report presents data obtained during prototype tests concerned with the performance of the 110- by 800-ft lock at Barkley Lock and Dam project, Cumberland River, Kentucky. Prototype measurements are continuous records of the following: (a) pressures ...

F. M. Neilson

1975-01-01

296

External fixator-assisted acute shortening with internal fixation for leg length discrepancy after total hip replacement  

PubMed Central

We report a case of a 51-year-old lady, who underwent a femoral shortening using a fixator assisted blade plate after total hip replacement. The patient had a total hip replacement on the other side with previous revisions, which resulted in a leg length discrepancy. We used the above technique to control the shortening and preserve the mechanical and anatomical axis of the femur.

Stockley, I.; Saleh, M.

2008-01-01

297

Refactoring Java programs for flexible locking  

Microsoft Academic Search

Recent versions of the Java standard library offer flexible locking constructs that go beyond the language’s built-in monitor locks in terms of features, and that can be fine-tuned to suit specific application scenarios. Under certain conditions, the use of these constructs can improve performance significantly, by reducing lock contention. However, the code transformations needed to convert between locking constructs are

Max Schäfer; Manu Sridharan; Julian Dolby; Frank Tip

2011-01-01

298

Lock Culvert Valves; Hydraulic Design Considerations.  

National Technical Information Service (NTIS)

This report presents a review of design guidance and hydraulic parameters associated with lock culvert valves. Many locks are beyond their design life, and the filling- and emptying-culvert valves are being replaced to keep the lock in service. Valve sele...

E. A. Hammack J. J. Hite R. L. Stockstill

2011-01-01

299

49 CFR 236.769 - Locking, traffic.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Locking, traffic. 236.769 Section 236.769 Transportation... Definitions § 236.769 Locking, traffic. Electric locking which prevents...other devices for changing the direction of traffic on a section of track while that...

2011-10-01

300

Stability Analysis of Troy Lock and Dam,  

National Technical Information Service (NTIS)

Troy Lock, Dam, and Powerhouse are located on the Hudson River in upstate New York (Figure 1) 156 miles from New York Harbor. Troy Lock and Dam allows entrance to the New York Barge Canal which connects to the Great Lakes. This makes Troy Lock and Dam an ...

C. Pace

1987-01-01

301

75 FR 2129 - Lock+TM  

Federal Register 2010, 2011, 2012, 2013

...13625-000] Lock+ TM Hydro Friends Fund XXX, LLC; Notice of Preliminary Permit Application...13, 2009, Lock+ TM Hydro Friends Fund XXX, LLC filed an application, pursuant to...Krouse, Lock+ TM Hydro Friends Fund XXX, LLC, 5090 Richmond Avenue...

2010-01-14

302

91. LOCKS CONTROL HOUSE & CRANE MACHINERY HOUSE ...  

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

91. LOCKS -- CONTROL HOUSE & CRANE MACHINERY HOUSE -- UPPER WEST WALL-- PLANS, ELEVATIONS, SECTIONS & VENT PLAN M-L 27 70/19. Lock and Dam No. 27 - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 27, Granite City, Madison County, IL

303

Plate Tectonics  

NSDL National Science Digital Library

This site contains 25 questions on the topic of plate tectonics, which covers the development of the theory, crustal movements, geologic features associated with tectonics, and plate boundaries (convergent, divergent, transform). This is part of the Principles of Earth Science course at the University of South Dakota. Users submit their answers and are provided immediate verification.

Heaton, Timothy

304

Automatic Locking Knee Brace Joint.  

National Technical Information Service (NTIS)

This invention is an apparatus for controlling the pivotal movement of a knee brace comprising a tang-and-clevis joint that has been uniquely modified. Both the tang and the clevis have a set of teeth that, when engaged, can lock the tang and the clevis t...

B. Weddendorf

1995-01-01

305

Spline-Locking Payload Fastener.  

National Technical Information Service (NTIS)

The invention consists of a locking spline payload fastener comprised of a spring-loaded male spline nut located at the tip of a threaded male positioning member that is affixed to a body being fastened. A complimentary female type spline fitting adapted ...

J. M. Vranish

1991-01-01

306

The variable finesse locking technique  

NASA Astrophysics Data System (ADS)

Virgo is a power recycled Michelson interferometer, with 3 km long Fabry-Perot cavities in the arms. The locking of the interferometer has been obtained with an original lock acquisition technique. The main idea is to lock the instrument away from its working point. Lock is obtained by misaligning the power recycling mirror and detuning the Michelson from the dark fringe. In this way, a good fraction of light escapes through the antisymmetric port and the power build-up inside the recycling cavity is extremely low. The benefit is that all the degrees of freedom are controlled when they are almost decoupled, and the linewidth of the recycling cavity is large. The interferometer is then adiabatically brought on to the dark fringe. This technique is referred to as variable finesse, since the recycling cavity is considered as a variable finesse Fabry-Perot. This technique has been widely tested and allows us to reach the dark fringe in few minutes, in an essentially deterministic way.

Acernese, F.; Amico, P.; Al-Shourbagy, M.; Aoudia, S.; Avino, S.; Babusci, D.; Ballardin, G.; Barillé, R.; Barone, F.; Barsotti, L.; Barsuglia, M.; Beauville, F.; Bizouard, M. A.; Boccara, C.; Bondu, F.; Bosi, L.; Bradaschia, C.; Braccini, S.; Brillet, A.; Brisson, V.; Brocco, L.; Buskulic, D.; Calloni, E.; Campagna, E.; Cavalier, F.; Cavalieri, R.; Cella, G.; Chassande-Mottin, E.; Corda, C.; Clapson, A.-C.; Cleva, F.; Coulon, J.-P.; Cuoco, E.; Dattilo, V.; Davier, M.; De Rosa, R.; Di Fiore, L.; Di Virgilio, A.; Dujardin, B.; Eleuteri, A.; Enard, D.; Ferrante, I.; Fidecaro, F.; Fiori, I.; Flaminio, R.; Fournier, J.-D.; Frasca, S.; Frasconi, F.; Freise, A.; Gammaitoni, L.; Gennai, A.; Giazotto, A.; Giordano, G.; Giordano, L.; Gouaty, R.; Grosjean, D.; Guidi, G.; Hebri, S.; Heitmann, H.; Hello, P.; Holloway, L.; Kreckelbergh, S.; La Penna, P.; Loriette, V.; Loupias, M.; Losurdo, G.; Mackowski, J.-M.; Majorana, E.; Man, C. N.; Mantovani, M.; Marchesoni, F.; Marion, F.; Marque, J.; Martelli, F.; Masserot, A.; Mazzoni, M.; Milano, L.; Moins, C.; Moreau, J.; Morgado, N.; Mours, B.; Pai, A.; Palomba, C.; Paoletti, F.; Pardi, S.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Perniola, B.; Piergiovanni, F.; Pinard, L.; Poggiani, R.; Punturo, M.; Puppo, P.; Qipiani, K.; Rapagnani, P.; Reita, V.; Remillieux, A.; Ricci, F.; Ricciardi, I.; Ruggi, P.; Russo, G.; Solimeno, S.; Spallicci, A.; Stanga, R.; Taddei, R.; Tombolato, D.; Tonelli, M.; Toncelli, A.; Tournefier, E.; Travasso, F.; Vajente, G.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinet, J.-Y.; Vocca, H.; Yvert, M.; Zhang, Z.; Evans, M.

2006-04-01

307

Interactive Systems Need Safety Locks  

Microsoft Academic Search

User interfaces often behave unpredictably on erroneous input - rather than blocking errors and requiring the user to correct them. The consequences of this in the context of medical devices, which may give patients undetected overdoses, can be unfortunate. The solution should include better design, including the concept of safety locks, that block some forms of user error.

Harold Thimbleby

2010-01-01

308

The conformational locking of asparagine.  

PubMed

One dominant structure has been identified analysing the rotational spectrum of asparagine in sharp contrast with the multiconformational behaviour for other amino acids with polar side chains. This locking of the conformational variety to a single conformer has been ascribed to an intramolecular hydrogen bonding network involving ?-amine, ?-carboxylic and amide groups. PMID:22573205

Cabezas, Carlos; Varela, Marcelino; Peña, Isabel; Mata, Santiago; López, Juan C; Alonso, José L

2012-05-10

309

Concurrent set manipulation without locking  

Microsoft Academic Search

Set manipulation consists of the actions insert, delete, and member on keys. We propose a concurrent set manipulation algorithm that uses no locking at all and requires no aborts, relying instead on atomic read-modify-write operations on single (data) locations. The algorithm satisfies order-preserving serializability through conditions that are strictly looser than existing algorithms

Vladimir Lanin; Dennis Shasha

1988-01-01

310

Fixator-assisted nailing and consecutive lengthening over an intramedullary nail for the correction of tibial deformity.  

PubMed

We report the results of using a combination of fixator-assisted nailing with lengthening over an intramedullary nail in patients with tibial deformity and shortening. Between 1997 and 2007, 13 tibiae in nine patients with a mean age of 25.4 years (17 to 34) were treated with a unilateral external fixator for acute correction of deformity, followed by lengthening over an intramedullary nail with a circular external fixator applied at the same operating session. At the end of the distraction period locking screws were inserted through the intramedullary nail and the external fixator was removed. The mean amount of lengthening was 5.9 cm (2 to 8). The mean time of external fixation was 90 days (38 to 265). The mean external fixation index was 15.8 days/cm (8.9 to 33.1) and the mean bone healing index was 38 days/cm (30 to 60). One patient developed an equinus deformity which responded to stretching and bracing. Another developed a drop foot due to a compartment syndrome, which was treated by fasciotomy. It recovered in three months. Two patients required bone grafting for poor callus formation. We conclude that the combination of fixator-assisted nailing with lengthening over an intramedullary nail can reduce the overall external fixation time and prevent fractures and deformity of the regenerated bone. PMID:20044694

Bilen, F E; Kocaoglu, M; Eralp, L; Balci, H I

2010-01-01

311

Obituary: Martha Locke Hazen, 1931-2006  

NASA Astrophysics Data System (ADS)

Longtime Harvard Curator of Astronomical Photographs and AAVSO officer Martha Hazen passed away on 23 December 2006 at Hingham, Massachusetts, after a short illness due to acute myelogenous leukemia. One of four children of Harold Locke and Katherine (neé Salisbury) Hazen, Martha was born in Cambridge, Massachusetts, on 15 July 1931, and raised in the Town of Belmont, near Cambridge, where she lived for most of her life. Her father coined the term "servo-mechanism" while serving as an engineering professor and dean for graduate students at the Massachusetts Institute of Technology. Her mother majored in chemistry at Mount Holyoke College. After receiving an A.B. in astronomy from Mount Holyoke College in 1953, Martha earned a Ph.D. in astronomy in 1958 from the University of Michigan, defending a dissertation on the distribution of intensity in elliptical galaxies in the Virgo cluster. Martha's marriage to William Liller in 1959, and the births of two children, inevitably slowed down her progress in observational astronomy. As a research fellow of the Harvard College Observatory, Martha continued to observe two to three weeks a year in Chile, and to reduce those observations and publish the results for sixteen years. Martha's first publication, at least as far as Astrophysics Data System includes the literature, was with Alice Farnsworth on the 1952 occultations of stars by the Moon, published in the Astronomical Journal (1953). In 1958 she joined L. R. Doherty and D. H. Menzel on a short note about the calculation of line profiles in a stratified atmosphere, her only theory paper. Martha's most cited paper is "The Distribution of Intensity in Elliptical Galaxies of the Virgo Cluster," (ApJ, 132, p.306, 1960). There she acknowledges Allan Sandage for suggesting the problem and providing some of the data. Her second most cited paper is "Photometric histories of QSOs - Two QSOs with large light amplitude," (Liller, M. H. & Liller, W., ApJ (Letters), 199, p. L133-L135, 1975). Progressing to smaller objects, other frequently cited papers are on eta Carinae and spectroscopic binaries in the globular cluster M3. All of these, and most of her other papers, involve photographic photometry, mostly using archival data. In 1969, Harvard appointed Martha Curator of Astronomical Photographs, placing her in responsible charge of the world renowned Harvard Plate Archives. Under attack during the mid-1950s because it occupied too much physical space, the collection had been neglected for over a decade when Martha assumed this additional responsibility. Though she continued to observe for a few years thereafter, her stewardship of the invaluable plate archives gradually demanded her full attention, which it held until her retirement in 2002. In her thirty-three years as curator of the plate stacks, as the archive is popularly known, Martha made numerous friends in both the professional and amateur communities. Astronomical researchers on a wide variety of topics relied on her detailed knowledge of the collection to guide them to important discoveries or discovery confirmations on the old plates, and to historical understanding of results in which some detail of origin needed clarification. Martha researched and documented the characteristics of nearly a hundred separate telescopic cameras used to take the plates archived in the collection. Much of this information was ephemeral, having been passed orally from observer to observer and was in danger of passing from human memory. This was, in itself, an enormous and valuable undertaking as it ensures the utility of the plates for future research. More importantly, Martha conserved and catalogued the all important logbooks that record the date, time, and other exposure circumstances for each of the plates in the collection. The full measure of Martha's long-term contribution in this regard undoubtedly will be realized as the digitization of the entire collection of plates is completed. The Digital Access to a Sky Century from Harvard (DASCH) project will ow

Williams, Thomas R.; Willson, Lee Anne

2007-12-01

312

Fixation disparity in binocular stress.  

PubMed

Fixation disparity has been taken as a sign of stress on binocular vision because it is established that prism stress creates fixation disparity. This paper looks at the effect on fixation disparity of the stress caused by requiring subjects to read in inadequate illumination. It is found that the reduction in illumination does not in itself immediately change the magnitude of the fixation disparity. There is, however, an increase in the mean slope of the central part of the fixation disparity curve which suggests that when the effect of reduced illumination is added to prism stress, fixation disparity is increased. The stress created by asking subjects to read in reduced illumination for half an hour resulted in the mean associated heterophoria being increased, and over half the subjects reported symptoms of stress. It is concluded that fixation disparity is changed by this type of visual stress in some subjects, and in near vision is increased to a more marked degree of exo-disparity. Most of this increase occurs in the first ten minutes. PMID:3658422

Pickwell, L D; Jenkins, T C; Yetka, A A

1987-01-01

313

Dynamic Holographic Lock-In Imaging of Ultrasonic Waves  

SciTech Connect

A laser imaging approach is presented that utilizes the adaptive property of photorefractive materials to produce a real-time measurement of ultrasonic traveling wave surface displacement and phase in all planar directions simultaneously without scanning. The imaging method performs optical lock-in operation. A single antisymmetric Lamb wave mode image produces direct quantitative determination of the phase velocity in all planar directions showing plate stiffness anisotropy. Excellent agreement was obtained with modeling calculations of the phase velocity in all planar directions for an anisotropic sheet material. The approach functions with diffusely scattering surfaces, subnanometer motions and at frequencies from Hz to GHz.

Telschow, Kenneth Louis; Deason, Vance Albert; Datta, S.K.

1999-05-01

314

Aspects of Stoicism in Locke’s Philosophy  

Microsoft Academic Search

\\u000a To begin with, Locke was not a Stoic philosopher, at least not a self-conscious one. There is no evidence that he made any\\u000a attempt to recover Stoic principles through a careful study of ancient sources that were available to him, one comparable\\u000a to the study he made of the New Testament in search of the fundamental principles of the Christian

Victor Nuovo

315

Biomechanical comparision of the stable efficacy of two anterior plating systems  

Microsoft Academic Search

Objective. To compare the immediate stable efficacy and load sharing effect of two types of anterior cervical screw-plating instrumentations: the Morscher Synthes titanium locking screw-plate system and the Caspar trapezoidal screw-plate system.Design. Fresh porcine cervical spines with intact, two surgery unstable models, and then reconstructed with or without screw-plating instruments were compared in three physiological loading conditions.Background. Two markedly instrumentation

Saiwei Yang; Lee-Wei Wang

2003-01-01

316

Performance of arm locking in LISA  

SciTech Connect

For the Laser Interferometer Space Antenna (LISA) to reach its design sensitivity, the coupling of the free-running laser frequency noise to the signal readout must be reduced by more than 14 orders of magnitude. One technique employed to reduce the laser frequency noise will be arm locking, where the laser frequency is locked to the LISA arm length. In this paper we detail an implementation of arm locking. We investigate orbital effects (changing arm lengths and Doppler frequencies), the impact of errors in the Doppler knowledge that can cause pulling of the laser frequency, and the noise limit of arm locking. Laser frequency pulling is examined in two regimes: at lock acquisition and in steady state. The noise performance of arm locking is calculated with the inclusion of the dominant expected noise sources: ultrastable oscillator (clock) noise, spacecraft motion, and shot noise. We find that clock noise and spacecraft motion limit the performance of dual arm locking in the LISA science band. Studying these issues reveals that although dual arm locking [A. Sutton and D. A. Shaddock, Phys. Rev. D 78, 082001 (2008)] has advantages over single (or common) arm locking in terms of allowing high gain, it has disadvantages in both laser frequency pulling and noise performance. We address this by proposing a modification to the dual arm-locking sensor, a hybrid of common and dual arm-locking sensors. This modified dual arm-locking sensor has the laser frequency pulling characteristics and low-frequency noise coupling of common arm locking, but retains the control system advantages of dual arm locking. We present a detailed design of an arm-locking controller and perform an analysis of the expected performance when used with and without laser prestabilization. We observe that the sensor phase changes beneficially near unity-gain frequencies of the arm-locking controller, allowing a factor of 10 more gain than previously believed, without degrading stability. With a time-delay error of 3 ns (equivalent of 1 m interspacecraft ranging error), time-delay interferometry (TDI) is capable of suppressing 300 Hz/{radical}(Hz) of laser frequency noise to the required level. We show that if no interspacecraft laser links fail, arm locking alone surpasses this noise performance for the entire mission. If one interspacecraft laser link fails, arm locking alone will achieve this performance for all but approximately 1 h per year, when the arm length mismatch of the two remaining arms passes through zero. Therefore, the LISA sensitivity can be realized with arm locking and time-delay interferometry only, without any form of prestabilization.

McKenzie, Kirk; Spero, Robert E.; Shaddock, Daniel A. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)

2009-11-15

317

Rigid skeletal fixation of fractures.  

PubMed

Rigid skeletal fixation of facial fractures has evolved from the principles established in orthopedics. It has taken a long time to develop rigid internal fixation devices that provide stability combined with safety. The application of rigid skeletal fixation to the facial skeleton requires the surgeon to pay strict attention to detail, which may add a small time increment to the procedure. However, the benefits to patients of having early use of the jaws and exact placement of bony segments seem to outweigh the disadvantages. The future of this constantly developing field will almost certainly center around technologic innovations that will make the application of fixation devices easier. It is likely that future research will provide devices that are more biocompatible, and perhaps just over the horizon, devices that are bioresorbable. PMID:8426256

Ellis, E

1993-02-01

318

Plate Motions  

NSDL National Science Digital Library

To prepare for this exercise students read the Chapter on plate tectonics in their text book. In class, they are given a color isochron map of the sea floor. They are given 4 tasks: Answer basic questions about the timing and rate of opening of the N. and S. Atlantic; Determine what has happened to the oceanic crust that is created on the eastern side of the East Pacific Rise; Determine what type of plate boundary existed on the western edge of the N. America plate before the San Andreas Fault and when this transition occurred; and Reconstruct the motion of the plates over the last 40 Ma assuming that the surface area of the Earth has not changed.

Nunn, Jeffrey

319

Plate Tectonics  

NSDL National Science Digital Library

Plate tectonic activity is being observed presently on a historic timescale, especially in the form of volcanic eruptions and earthquakes, but, as with many large-scale Earth science phenomena, it is hard to ...

320

Biological fixation of endosseous implants  

Microsoft Academic Search

Primary implant stability is ensured by a mechanical fixation of implants. However, during implant healing a biological anchorage is necessary to achieve final osseointegration.Aim of this study was to investigate the histological aspects of biological fixation around titanium screws.Forty-eight titanium screws with different surfaces (smooth, plasma sprayed, sand blasted) were inserted in tibiae and femura of sheep and analyzed by

M. Franchi; M. Fini; D. Martini; E. Orsini; L. Leonardi; A. Ruggeri; G. Giavaresi; V. Ottani

2005-01-01

321

Dall-Miles cable and plate system for periprosthetic femoral fracture  

Microsoft Academic Search

Management of femoral shaft fractures in association with hip implants in situ is a difficult and complex problem. We present here our experience of nine periprosthetic femoral fractures treated successfully with open reduction and internal fixation using the Dall-Miles plate and cable system. We recommend this system for fixation of the type 3 fractures using a minimum of three proximal

N. H. Shah; J. P. McCabe

2002-01-01

322

Experimental and finite element comparison of various fixation designs in combined loads.  

PubMed

The short- and long-term successes of tibial cementless implants depend on the initial fixation stability often provided by posts and screws. In this work, a metallic plate was fixed to a polyurethane block with either two bone screws, two smooth-surfaced posts, or two novel smooth-surfaced posts with adjustable inclinations. For this last case, inclinations of 0, 1.5, and 3 deg were considered following insertion. A load of 1031 N was eccentrically applied on the plate at an angle of approximately 14 deg, which resulted in a 1000 N axial compressive force and a 250 N shear force. The response was measured under static and repetitive loading up to 4000 cycles at 1 Hz. The measured results demonstrate subsidence under load, lift-off on the unloaded side, and horizontal translation of the plate specially at the loaded side. Fatigue loading increased the displacements, primarily during the first 100 cycles. Comparison of various fixation systems indicated that the plate with screw fixation was the stiffest with the least subsidence and liftoff. The increase in post inclination from 0 to 3 deg stiffened the plate by diminishing the liftoff. All fixation systems demonstrated deterioration under repetitive loads. In general, the finite element predictions of the experimental fixation systems were in agreement with measurements. The finite element analyses showed that porous coated posts (modeled with nonlinear interface friction with and without coupling) generated slightly less resistance to liftoff than smooth-surfaced posts. In the presence of porous coated posts, Coulomb friction greatly overestimated the rigidity by reducing the liftoff and subsidence to levels even smaller than those predicted for the design with screw fixation. The sequence of combined load application also influenced the predicted response. Finally, the finite element model incorporating measured interface friction and pull-out responses can be used for the analysis of cementless total joint replacement systems during the post-operation period. PMID:11601722

Shirazi-Adl, A; Patenaude, O; Dammak, M; Zukor, D

2001-10-01

323

Combination tether and locking device  

US Patent & Trademark Office Database

A combination snowboard tether, security lock, and carrying strap featuring a metal cable permanently or removably attached to a snowboard. The device may be permanently or removably secured to a snow board. The cable during use as a tether is maintained in a relatively upright position out of the snow and away from rocks and branches using positioning locators mounted on the cable in a fashion to limit the rotation of the cable when inserted into cooperating receiving cavities or notches for the positioning locators located in an eye bolt attached to the snowboard. The device has a lock mounted upon the ends of the cable to allow for the cable to be secured around a stationary object during periods when the board is not being used. The cable may also be used as a carrying strap by positioning it over the shoulder.

1999-05-18

324

Nitrogen Fixation (Acetylene Reduction) Associated with Duckweed (Lemnaceae) Mats  

PubMed Central

Duckweed (Lemnaceae) mats in Texas and Florida were investigated, using the acetylene reduction assay, to determine whether nitrogen fixation occurred in these floating aquatic macrophyte communities. N2-fixing microorganisms were enumerated by plating or most-probable-number techniques, using appropriate N-free media. Results of the investigations indicated that substantial N2-fixation (C2H2) was associated with duckweed mats in Texas and Florida. Acetylene reduction values ranged from 1 to 18 ?mol of C2H4 g (dry weight)?1 day?1 for samples incubated aerobically in light. Dark N2 fixation was always two- to fivefold lower. 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (7 to 10 ?M) reduced acetylene reduction to levels intermediate between light and dark incubation. Acetylene reduction was generally greatest for samples incubated anaerobically in the light. It was estimated that 15 to 20% of the N requirement of the duckweed could be supplied through biological nitrogen fixation. N2-fixing heterotrophic bacteria (105 cells g [wet weight]?1 and cyanobacteria (105 propagules g [wet weight]?1 were associated with the duckweed mats. Azotobacter sp. was not detected in these investigations. One diazotrophic isolate was classified as Klebsiella.

Zuberer, D. A.

1982-01-01

325

Proximal tibia medial open-wedge osteotomy using plates with wedges: early results in 58 cases  

Microsoft Academic Search

We evaluated in this study indications, surgical technique, and results of wedge plates for fixation in proximal tibia medial opening wedge osteotomy. Fifty-eight knees in 56 consecutive patients (9 men, 47 women; mean age 52 years; ranging between 36 and 66 years) with medial compartment osteoarthrosis were treated with proximal tibia medial open-wedge osteotomy. For fixation, plates which were designed by the

Irfan Esenkaya; Nurzat Elmali

2006-01-01

326

Cervical anterior transpedicular screw fixation. Part I: Study on morphological feasibility, indications, and technical prerequisites  

Microsoft Academic Search

Multilevel cervical spine procedures can challenge the stability of current anterior cervical screw-and-plate systems, particularly\\u000a in cases of severe three-column subaxial cervical spine injuries and multilevel plated reconstructions in osteoporotic bone.\\u000a Supplemental posterior instrumentation is therefore recommended to increase primary construct rigidity and diminish early\\u000a failure rates. The increasing number of successfully performed posterior cervical pedicle screw fixations have enabled

Heiko Koller; Axel Hempfing; Frank Acosta; Michael Fox; Armin Scheiter; Mark Tauber; Ulrich Holz; Herbert Resch; Wolfgang Hitzl

2008-01-01

327

Fuss, Futexes and Furwocks: Fast Userlevel Locking in Linux  

Microsoft Academic Search

Fast userlevel locking is an alternative locking mechanism to the typically heavy weight ker- nel approaches such as fcntl locking and Sys- tem V semaphores. Here, multiple processes communicate locking state through shared memory regions and atomic operations. Ker- nel involvement is only necessary when there is contention on a lock, in order to perform queueing and scheduling functions. In

Hubertus Franke; Rusty Russell; Matthew Kirkwood

328

1. LOCK CHAMBER, LOOKING NORTH. WITH A DEPTH OF 16 ...  

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

1. LOCK CHAMBER, LOOKING NORTH. WITH A DEPTH OF 16 FEET, LOCK #28 WAS THE DEEPEST LOCK IN THAT PORTION OF THE OHIO AND ERIE CANAL BETWEEN AKRON AND CLEVELAND, HENCE ITS POPULAR NAME,'DEEP LOCK'. - Ohio & Erie Canal, Lock No. 28, East of Junction of Major & Riverview Roads, Peninsula, Summit County, OH

329

Femoral Reconstruction Using External Fixation  

PubMed Central

Background. The use of an external fixator for the purpose of distraction osteogenesis has been applied to a wide range of orthopedic problems caused by such diverse etiologies as congenital disease, metabolic conditions, infections, traumatic injuries, and congenital short stature. The purpose of this study was to analyze our experience of utilizing this method in patients undergoing a variety of orthopedic procedures of the femur. Methods. We retrospectively reviewed our experience of using external fixation for femoral reconstruction. Three subgroups were defined based on the primary reconstruction goal lengthening, deformity correction, and repair of nonunion/bone defect. Factors such as leg length discrepancy (LLD), limb alignment, and external fixation time and complications were evaluated for the entire group and the 3 subgroups. Results. There was substantial improvement in the overall LLD, femoral length discrepancy, and limb alignment as measured by mechanical axis deviation (MAD) and lateral distal femoral angle (LDFA) for the entire group as well as the subgroups. Conclusions. The Ilizarov external fixator allows for decreased surgical exposure and preservation of blood supply to bone, avoidance of bone grafting and internal fixation, and simultaneous lengthening and deformity correction, making it a very useful technique for femoral reconstruction.

Palatnik, Yevgeniy; Rozbruch, S. Robert

2011-01-01

330

2?m mode-locked fiber lasers  

NASA Astrophysics Data System (ADS)

Mode-locked fiber lasers based on Tm-doped and Tm-Ho-codoped silicate fibers have been studied. The first modelocked fiber laser oscillator beyond 2 ?m was demonstrated. The first mode-locked 2?m fiber laser with ~GHz repetition rate was demonstrated. The broadest spectrum (50nm FWHM) was obtained from dispersion managed 2?m mode-locked fiber laser. Various operation regimes of mode-locked thulium fiber lasers are presented, as well as all-fiber 2?m pulse amplifiers.

Wang, Qing; Geng, Jihong; Luo, Tao; Jiang, Shibin

2012-02-01

331

Drilling riser locking apparatus and method  

SciTech Connect

Method and apparatus for use in drilling a well from a floating vessel by means of a riser, which connects the vessels drilling equipment to a wellhead assembly adjacent the ocean floor. The riser is capable of being disconnected from the wellhead assembly, and having its upper end locked to the vessel. The present riser locking apparatus is made up of selectively-positionable resiliently-moveable locking beams adapted to be remotely actuated to lock the upper elements of the riser to the vessel, thereby preventing lateral or vertical movement of the riser relative to the vessel.

Denison, E. B.; Picard, J. M.

1985-12-10

332

Vascular injury involving proximal medial-to-lateral oblique locking screw insertion in tibial intramedullary nailing.  

PubMed

Orthopaedic surgeons have reported increased neurologic complications with the employment of next-generation tibial nail fixation with variable proximal and distal locking options. However, vascular injury due to oblique screw placement has not been documented. We describe a case in which a medial-to-lateral oblique locking screw led to significant vascular injury. The judicious use of these screws and their relative contribution to fracture stability should be carefully considered for individual cases. Additionally, drill penetration through the far tibial cortex may not be obvious and utilizing oscillation or reverse drilling techniques may be of benefit. Lastly, the forward thrust of the popliteal artery with the use of a positioning bump in the popliteal fossa may place the vascular structure at increased risk of injury. Employing means to avoid these injuries and minimize risks in pertinent patients is of utmost importance. PMID:21846016

Hussain, Waqas; Balach, Tessa; Leland, J Martin

2011-06-01

333

Wide plate margin deformation, southern Central America and northwestern South America, CASA GPS observations  

Microsoft Academic Search

Global positioning system data from southern Central America and northwestern South America were collected during 1991, 1994, 1996, and 1998 in Costa Rica, Panama, Ecuador, Colombia, and Venezuela. These data reveal wide plate boundary deformation and escape tectonics occurring along an approximately 1400km length of the North Andes, locking of the subducting Nazca plate and strain accumulation in the Ecuador–Colombia

Robert Trenkamp; James N. Kellogg; Jeffrey T. Freymueller; Hector P. Mora

2002-01-01

334

A biomechanical study of the fatigue characteristics of thoracolumbar fixation implants in a calf spine model.  

PubMed

Clinical failures of internal fixation implants for the treatment of the thoracolumbar spine are generally attributed to fatigue. Few studies, however, have characterized changes in fixation rigidity with time or subjected spine-implant fixation constructs to fatigue loading until failure. Fatigue characteristics of five dorsally applied spinal fixation implants were determined using lumbosacral calf spines, with an L3 vertebrectomy, loaded cyclically in combined compression (maximum 605 N) and flexion (maximum 16 Nm) for up to 100,000 cycles. Displacement transducers monitored motion at the site of instability and at the segment above the implants. Flexibility and strain at these segments were then calculated. A one-way analysis of variance showed that there were no significant differences in flexibility of the five fixation constructs (P greater than .05). A multiple Bonferroni test revealed that the AO and Kluger fixateur interne and Steffee plates, with fixation at L2 and L4, allowed significantly more strain (P less than .01) across the site of instability than did Harrington rods and Luque plates with fixation at L1, L2, L4, and L5. There were no significant differences between fixation constructs in initial strain above the implants. After 10,000 cycles, however, there were significant increases in strain across the segment above the Luque and Harrington implants (P less than .05). Failure of the AO Schanz screw occurred in three of six constructs at a mean of 73,300 cycles. The Steffee screws failed in four of five constructs at a mean of 20,800 cycles. The rods of the Kluger fixateur interne broke in four of five constructs at a mean of 47,800 cycles, and one screw slipped at 11,000 cycles. There were no metal failures in the Harrington or Luque implants.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1631711

Wittenberg, R H; Shea, M; Edwards, W T; Swartz, D E; White, A A; Hayes, W C

1992-06-01

335

A case of needle fixation.  

PubMed

Needle fixation is frequently missed and dismissed by clinicians and patients. However, ignoring this condition can have severe consequences, such as septicaemia, thrombosis, blood borne viruses, and is associated with an overall poor prognosis of drug dependence.Here we describe a 37-year-old man who presented with 20-year history of polydrug dependence, drug-induced psychosis and antisocial personality disorder. He was found to also have a 5-year history of intermittent needle fixation. His injecting behaviour and drug use improved significantly with fluoxetine while being on methadone maintenance.At present there is little evidence for any effective treatment strategies for needle fixation. The current recommended treatment consists of cognitive behavioural therapy and cue exposure. Whether fluoxetine constitutes an effective management strategy remains to be seen. PMID:22479297

Treffurth, Yvonne; Pal, Hem Raj

2010-04-05

336

49 CFR 236.302 - Track circuits and route locking.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Track circuits and route locking. 236.302 Section 236...Interlocking Standards § 236.302 Track circuits and route locking. Track circuits and route locking shall be provided...

2011-10-01

337

VIEW LOOKING SOUTH SOUTHWEST AT THE BASE OF THE LOCKS. ...  

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

VIEW LOOKING SOUTH SOUTHWEST AT THE BASE OF THE LOCKS. THE ERIE CANAL MUSEUM (FORMER LOCK POWER PLANT) IS THE STRUCTURE IN THE CENTER OF THE VIEW. - New York State Barge Canal, Lockport Locks, Richmond Avenue, Lockport, Niagara County, NY

338

170. VIEW OF UNIDENTIFIED LOCK SHOWING DOORS PARTIALLY OPEN. IRON ...  

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

170. VIEW OF UNIDENTIFIED LOCK SHOWING DOORS PARTIALLY OPEN. IRON RODS STICKING UP FROM GATES OPERATE PADDLES THAT ALLOWS WATER IN LOCK TO EQUALIZE WITH WATER IN CANAL DURING THE LOCKING PROCEDURE. - Morris Canal, Phillipsburg, Warren County, NJ

339

32. OVERALL VIEW OF MAIN (LEFT) AND AUXILIARY (RIGHT) LOCKS, ...  

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

32. OVERALL VIEW OF MAIN (LEFT) AND AUXILIARY (RIGHT) LOCKS, SHOWING GUIDEWALLS, DOWNSTREAM MITER GATES IN OPEN POSITION AND LOCK INTERIOR, LOOKING NORTH - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 10, Guttenberg, Clayton County, IA

340

12. VIEW OF OUTLET LOCKS AND RARITAN RIVER, LOOKING NORTH ...  

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

12. VIEW OF OUTLET LOCKS AND RARITAN RIVER, LOOKING NORTH FROM APPROXIMATE SITE OF FORMER LOCK TENDER'S HOUSE - Delaware & Raritan Canal, Outlet Locks, Between State Route 18 & Raritan River, New Brunswick, Middlesex County, NJ

341

Cost Advantages of Two-Level Anterior Cervical Fusion with Rigid Internal Fixation for Radiculopathy and Degenerative Disease  

Microsoft Academic Search

BackgroundConventional anterior cervical discectomy with fusion is thought to require postoperative neck immobilization for the promotion of bony fusion. Rigid internal fixation with anterior cervical plates may decrease graft-related complications and provide immediate stability. This stability may obviate postoperative external immobilization.MethodsThis report reviews one surgeon’s experience with the use of rigid internal fixation for two-level anterior cervical discectomy and fusion

Mark R McLaughlin; Vasan Purighalla; Francis J Pizzi

1997-01-01

342

An inexpensive and available external fixator.  

PubMed

This article introduces a simple and inexpensive external fixator device which has been designed and manufactured from materials readily available in this country. It is called the Doxa Fixator. PMID:11391841

Dagbue, N A

343

Formal Reasoning about Concurrent Assembly Code with Reentrant Locks  

Microsoft Academic Search

Abstract—This paper focuses on the problem,of reason- ing about concurrent assembly code with reentrant locks. Our verification technique is based on concurrent separatio n logic (CSL). In CSL, locks are treated as non-reentrant locks and each lock is associated with a resource invariant, the lock-protected resources are obtained and,released through acquiring and,releasing the lock respectively. In order to accommodate for

Ming Fu; Yu Zhang; Yong Li

2009-01-01

344

VIEW LOOKING NORTHEAST FROM THE PINE STREET BRIDGE. THE LOCK ...  

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

VIEW LOOKING NORTHEAST FROM THE PINE STREET BRIDGE. THE LOCK ACCESS ROAD (FORMER TOW PATH) IS AT THE EXTREME LEFT, AND LOCKS 69 THROUGH 67 ARE IN THE CENTER LEFT, THE LOCK MACHINE SHOP IS IN THE MID-GROUND CENTER, AND THE ERIE CANAL MUSEUM (FORMER LOCK POWER PLANT) IN THE BACKGROUND CENTER. THE BARGE CANAL LOCK 34 IS AT THE EXTREME RIGHT. - New York State Barge Canal, Lockport Locks, Richmond Avenue, Lockport, Niagara County, NY

345

Locking of the metacarpophalangeal joint of the thumb with the radial collateral ligament rupture after stress radiography.  

PubMed

Stress test is a commonly used diagnostic examination to evaluate the radial collateral ligament (RCL) tear of the thumb metacarpophalangeal (MCP) joint to indicate the surgical intervention. We experienced a locked MCP joint after stress test in a patient with the RCL and volar plate injury. PMID:19609539

Lee, Sanglim; Yum, Jae-kwang; Kim, Ji Yeong

2009-07-16

346

[Claw plates--new implants for para-articular osteosynthesis].  

PubMed

The claw plate types used by us are manufactured according to the same principle. These plates are mostly applied in the treatment of multiple fragment fractures and in the fixation of osteotomies. A strong fixation of the plate, also to little fragments close to the joint, is achieved by the claws and one screw. The plates may be used for neutralization or as a support, distance piece, or compression plate. The shape of the variable plate as well as the claws can be formed. The masses of the maximum and minimum plate are adapted to the different sizes of bones. No special instrument is needed to insert the claw plate, and the region around the joint can be laid open in a sparing manner. Regarding the experience accumulated during ten years and the good results obtained, we are of the opinion that claw plates can be used successfully to complete the methods applied hitherto in the treatment of joint-near fractures of all long bones except the femur. PMID:3824689

Berentey, G; Feczkó, J; Sárváry, A

1986-12-01

347

Noise in phase-locked loops  

Microsoft Academic Search

Jitter and phase noise properties of phase-locked loops (PLL) are analyzed, identifying various forms of jitter and phase noise in PLLs. The effects of different building blocks on the jitter and phase noise performance of PLLs are demonstrated through a parallel analytical and graphical treatment of noise evolution in the phase-locked loop

Ali Hajimiri

2001-01-01

348

Past, Present, Future Erosion at Locke Island  

SciTech Connect

This report describes and documents the erosion that has occurred along the northeast side of Locke Island over the last 10 to 20 years. The principal cause of this erosion is the massive Locke Island landslide complex opposite the Columbia River along the White Bluffs, which constricts the flow of the river and deflects the river's thalweg southward against the island.

Bjornstad, Bruce N.

2006-08-08

349

46 CFR 108.157 - Locked doors.  

Code of Federal Regulations, 2012 CFR

... 4 2012-10-01 2012-10-01 false Locked doors. 108.157 Section 108.157 Shipping COAST...Arrangement Means of Escape § 108.157 Locked doors. No door to the required means of escape may be designed to...

2012-10-01

350

Fatigue crack identification using near-tip singular temperature field measured by lock-in thermography  

NASA Astrophysics Data System (ADS)

Applicability of the newly developed two different lock-in thermographic NDT techniques is discussed. One of the proposed techniques is based on the lock-in measurement of the singular temperature field, which appears near crack tips under the application of periodically modulated electric current. Experimental study is made on the resolution and the applicability in the detection of through-thickness cracks embedded in steel and aluminum alloy plate samples. Modulated electric current is applied to the cracked sample by an induction coil. Temperature amplitude and phase delay thermal images synchronized to the reference current modulation signal are taken by the lock-in thermography. Significant temperature rise related to singular temperature field is observed at the crack tips in the lock-in thermal images. It is found that the cracks are sensitively detected by the lock-in thermography technique combined with near-tip singular temperature field measurement. The other technique is based on the lock-in measurement of the surface temperature under the application of periodical xenon light heating. Experimental study is made on the applicability to the detection of flat objective body. In-phase and out-of-phase temperature amplitude images are taken by the lock-in thermography, synchronized to the reference signal of the electric shutter operation. It is found that the location and size of the defects can be identified by the localized contrast change in the out-of- phase images. Further, the depths of the defects can be identified from the heat penetration depth, which is changed by the frequency of thermal wave stimulation.

Sakagami, Takahide; Kubo, Shiro; Teshima, Yasuhiro

2000-03-01

351

Fixation biases affecting human SNPs  

Microsoft Academic Search

Under neutrality all classes of mutation have an equal probability of becoming fixed in a population. In this article, we describe our analysis of the frequency distributions of >5000 human SNPs and provide evidence of biases in the process of fixation of certain classes of point mutation that are most likely to be attributable to biased gene conversion. The results

Matthew T. Webster; Nick G. C. Smith

2004-01-01

352

Polymeric media for tritium fixation  

Microsoft Academic Search

The synthesis and leach testing of several polymeric media for tritium ; fixation are presented. Tritiated bakelite, poly(acrylonitrile) and polystyrene ; successfully fixed tritium. Tritium leach rates at the tracer level appear to be ; negligible. Advantages and disadvantages of the processes are discussed, and ; further bench-scale investigations underway are reported. Rough cost estimates ; are presented for the

J. A. Franz; L. L. Burger

1975-01-01

353

Quantitative Approach to Camera Fixation.  

National Technical Information Service (NTIS)

The paper deals with quantitative aspects of camera fixation for a static scene. In general, when the camera undergoes translation and rotation, there is an infinite number of points that produce equal optical flow for any instantaneous point in time. Usi...

D. Raviv

1990-01-01

354

Methacarn (methanol-Carnoy) fixation  

Microsoft Academic Search

According to chemical data, methanol raises the shrinkage temperature of collagen significantly more than ethanol (86° C versus 70° C). Since increase of shrinkage temperature appears desirable in tissues to be embedded in paraffin, methanol was substituted for ethanol in Carnoy's fluid. This methanol-Carnoy mixture is referred to as methacarn solution. The fixation-embedding procedure was similar to that described in

Holde Puchtler; Faye Sweat Waldrop; Susan N. Meloan; Mary S. Terry; H. M. Conner

1970-01-01

355

Fixation of microsporidian spores for electron microscopy.  

PubMed

Fresh and frozen spores of the microsporidia Nosema apis and Nosema bombi were fixed using various fixatives at different times and temperatures. Paraformaldehyde and technical formaldehyde gave results comparable to or better than glutaraldehyde. Increased fixation temperature improved the fixation of spores from terrestrial hosts. Freezing did not destroy the cytology of the spore. PMID:16112682

Larsson, J I Ronny

2005-08-19

356

Osmolarity of osmium tetroxide and glutaraldehyde fixatives  

Microsoft Academic Search

Synopsis  The evidence available to date for the importance of fixative osmolarity is considered together with some observations on the volume changes of crab axons after fixation by osmium tetroxide and glutaraldehyde. The results obtained are compared with those obtained from crab axons and from amphioxus skin cells which had been processed and examined with the electron microscope after initial fixation

Q. Bone; K. P. Ryan

1972-01-01

357

Allograft interference screw fixation in meniscus transplantation  

Microsoft Academic Search

Allograft meniscus transplantation is indicated to restore proper knee biomechanics and prevent subsequent articular degeneration in patients with a meniscus-deficient knee. A variety of techniques for fixation of meniscal transplants exist, with some techniques using soft-tissue fixation of the meniscal horns and others using bony fixation. The authors present a technique of meniscus transplantation using a tibial slot with allograft

Jack Farr; R. Michael Meneghini; Brian J. Cole

2004-01-01

358

Bone plate  

US Patent & Trademark Office Database

A bone plate assembly and method of use comprising a head; a shaft; an upper surface; a lower surface having a fixed plane intended to be adjacent to the patient's bone when the plate is in use; a first hole positioned in the head wherein the first hole passes through the upper and lower surfaces and is configured to fix a shaft of a first bone anchor along a first axis; a second hole positioned on the anterior portion of the upper surface of the head wherein the second hole passes through the upper and lower surfaces and is configured to fix a shaft of a second bone anchor along a second axis; and a third hole positioned in the posterior side of the head wherein the third hole passes through the upper and lower surfaces and is configured to fix a shaft of a third bone anchor along a third axis, wherein the first axis, the second axis and the third axis do not intersect in the bone when the plate is in use.

Gehlert; Rick J. (Albuquerque, NM)

2012-09-18

359

Understanding Nitrogen Fixation  

SciTech Connect

The purpose of our program is to explore fundamental chemistry relevant to the discovery of energy efficient methods for the conversion of atmospheric nitrogen (N{sub 2}) into more value-added nitrogen-containing organic molecules. Such transformations are key for domestic energy security and the reduction of fossil fuel dependencies. With DOE support, we have synthesized families of zirconium and hafnium dinitrogen complexes with elongated and activated N-N bonds that exhibit rich N{sub 2} functionalization chemistry. Having elucidated new methods for N-H bond formation from dihydrogen, C-H bonds and Broensted acids, we have since turned our attention to N-C bond construction. These reactions are particularly important for the synthesis of amines, heterocycles and hydrazines with a range of applications in the fine and commodity chemicals industries and as fuels. One recent highlight was the discovery of a new N{sub 2} cleavage reaction upon addition of carbon monoxide which resulted in the synthesis of an important fertilizer, oxamide, from the diatomics with the two strongest bonds in chemistry. Nitrogen-carbon bonds form the backbone of many important organic molecules, especially those used in the fertilizer and pharamaceutical industries. During the past year, we have continued our work in the synthesis of hydrazines of various substitution patterns, many of which are important precursors for heterocycles. In most instances, the direct functionalization of N{sub 2} offers a more efficient synthetic route than traditional organic methods. In addition, we have also discovered a unique CO-induced N{sub 2} bond cleavage reaction that simultaneously cleaves the N-N bond of the metal dinitrogen compound and assembles new C-C bond and two new N-C bonds. Treatment of the CO-functionalized core with weak Broensted acids liberated oxamide, H{sub 2}NC(O)C(O)NH{sub 2}, an important slow release fertilizer that is of interest to replace urea in many applications. The synthesis of ammonia, NH{sub 3}, from its elements, H{sub 2} and N{sub 2}, via the venerable Haber-Bosch process is one of the most significant technological achievements of the past century. Our research program seeks to discover new transition metal reagents and catalysts to disrupt the strong N {triple_bond} N bond in N{sub 2} and create new, fundamental chemical linkages for the construction of molecules with application as fuels, fertilizers and fine chemicals. With DOE support, our group has discovered a mild method for ammonia synthesis in solution as well as new methods for the construction of nitrogen-carbon bonds directly from N{sub 2}. Ideally these achievements will evolve into more efficient nitrogen fixation schemes that circumvent the high energy demands of industrial ammonia synthesis. Industrially, atmospheric nitrogen enters the synthetic cycle by the well-established Haber-Bosch process whereby N{sub 2} is hydrogenated to ammonia at high temperature and pressure. The commercialization of this reaction represents one of the greatest technological achievements of the 20th century as Haber-Bosch ammonia is responsible for supporting approximately 50% of the world's population and serves as the source of half of the nitrogen in the human body. The extreme reaction conditions required for an economical process have significant energy consequences, consuming 1% of the world's energy supply mostly in the form of pollution-intensive coal. Moreover, industrial H{sub 2} synthesis via the water gas shift reaction and the steam reforming of methane is fossil fuel intensive and produces CO{sub 2} as a byproduct. New synthetic methods that promote this thermodynamically favored transformation ({Delta}G{sup o} = -4.1 kcal/mol) under milder conditions or completely obviate it are therefore desirable. Most nitrogen-containing organic molecules are derived from ammonia (and hence rely on the Haber-Bosch and H{sub 2} synthesis processes) and direct synthesis from atmospheric nitrogen could, in principle, be more energy-efficient. This is particularly attractive giv

Paul J. Chirik

2012-05-25

360

Dangerous Earth: A Plate Tectonic Story  

NSDL National Science Digital Library

This article and accompanying questions discusses the fact that several of the Earth's tectonic plates move at about the same speed as fingernails grow - around 35 mm per year - and that the plates are made of lithosphere (crust plus the upper part of the mantle). Students will also learn that beneath the lithosphere is the asthenosphere, part of the upper mantle that is ductile because it contains 1-10 percent molten material as films around the crystals. In addition they will find that the Earth's magnetic field has flipped (the N pole becoming the S pole, and vice versa) many times throughout geological time, resulting in rocks with varying directions of magnetism. They will also find that as tectonic plates move apart, new rock is formed and this locks in the direction of the magnetic field at the time.

361

Balser plate stabilization: an alternate therapy for traumatic sternoclavicular instability  

Microsoft Academic Search

Traumatic instability of the sternoclavicular joint is a rare condition. It can be treated by surgical cerclage fixation, which necessitates postoperative immobilization, an approach preventing early postoperative functional rehabilitation. Balser plate stabilization is a therapeutic alternative that does not require extended periods of immobilization. From January 1, 1996, to December 31, 2000, a total of 10 trauma patients with unstable

Wolfgang M Franck; Olof Jannasch; Michael Siassi; Friedrich F Hennig

2003-01-01

362

A biomechanical evaluation of mandibular condyle fracture plating techniques  

Microsoft Academic Search

Objectives: The purpose of this investigation was to evaluate the biomechanical behavior of various rigid internal fixation techniques for mandibular condylar process fractures. Materials and Methods: Synthetic mandible replicas (Synbone, Landquart, Switzerland) were used to evaluate a control, and four monocortical mandibular condyle plating techniques. Each group was subjected to linear loading in lateral to medial, medial to lateral and

Richard H. Haug; Gilman P. Peterson; Michele Goltz

2002-01-01

363

Superior versus anteroinferior plating of clavicle fractures.  

PubMed

Plate fixation of displaced clavicle fractures has proven to be reliable and reproducible, leading to high union rates and a low rate of associated complications. However, the decision of whether to place the plate superiorly or anteroinferiorly on the clavicle has remained controversial. The authors performed a retrospective review on a consecutive series of patients who underwent plate fixation for a displaced midshaft clavicle fracture at a Level I urban trauma center. A review of surgical records identified 138 patients with a displaced midshaft clavicle fracture requiring operative stabilization. A total of 105 patients who met the inclusion criteria were included in the analysis. Both superior and anteroinferior techniques resulted in a similar time to radiographic union (12.6±4.8 vs 11.3±5.2 weeks, respectively) and identical union rates (95%). At final follow-up, patient-reported implant prominence was nearly double in patients with a retained superior plate (54% vs 29%, respectively; P=.04). No significant difference existed in mean visual analog scale score at a mean of 2.77 years postoperatively, although a significant difference existed in the Oxford Shoulder Score questionnaire, with a mean score of 41.4 in the superior group and 44.4 in the anteroinferior group (P=.008). Implant removal occurred more frequently after superior plating but was not significant. Both superior and anteroinferior clavicle plating are safe treatment methods for displaced clavicle fractures. Superior plating leads to an increased rate of patient-reported implant prominence and may prompt more requests for implant removal. PMID:23823047

Formaini, Nathan; Taylor, Benjamin C; Backes, Jeffrey; Bramwell, Thomas J

2013-07-01

364

NONLINEAR FLUTTER OF LAMINATED PLATES WITH IN-PLANE FORCE AND TRANSVERSE SHEAR EFFECTS  

Microsoft Academic Search

Based on a simplified higher-order shear deformation plate theory (SDPT) and von Karman large deformation assumption, a high-precision higher-order triangular-plate element that can be used to deal with transverse shear effects is developed for the nonlinear flutter analysis of composite laminates. The element presents no shear-locking problem due to the assumption that the total transverse displacement of the plate is

Le-Chung Shiau; Teng-Yuan Wu

2001-01-01

365

Clinical experience with a new load-sharing anterior cervical plate  

Microsoft Academic Search

Purpose of study: Anterior plate fixation is widely accepted as an adjunct to surgical correction of traumatic or degenerative conditions of the cervical spine. The various systems have evolved from nonconstrained constructs to rigid plate screw constructs. With the popularity of the latter, concerns have increased on both the biomechanical and clinical levels regarding the adverse effects of graft stress

Ronald I Apfelbaum; Andrew T Dailey; Scott Soleau; Jose Barbera

2002-01-01

366

Unusual Cause of Knee Locking  

PubMed Central

We report a case of partial intrasubstance tear of popliteus tendon as an unusual cause of pseudolocking of the knee. A 13-year-old semiprofessional soccer player applied to our clinic with a locked right knee in spite of the therapy applied (cold pack, NSAID, and immobilization) in another institution 20 days after the injury. Significant extension loss was observed in his right knee with 30°–90°?ROM. Magnetic resonance imaging (MRI) and arthroscopy confirmed the intrasubstance tear of popliteus tendon and synovitis. The ruptured part of the tendon was debrided, and the inflammatory tissue around the tendon, which may lead to pseudolocking, was gently removed with a shaver in order to regain the normal ROM. The patient was discharged with full ROM and weight bearing first day after the surgery. To our knowledge, this is the first case demonstrating intrasubstance tear of popliteus tendon causing pseudolocking of the knee.

Huri, Gazi; Bicer, Omer Sunkar

2013-01-01

367

Delay locked loop integrated circuit.  

SciTech Connect

This report gives a description of the development of a Delay Locked Loop (DLL) integrated circuit (IC). The DLL was developed and tested as a stand-alone IC test chip to be integrated into a larger application specific integrated circuit (ASIC), the Quadrature Digital Waveform Synthesizer (QDWS). The purpose of the DLL is to provide a digitally programmable delay to enable synchronization between an internal system clock and external peripherals with unknown clock skew. The DLL was designed and fabricated in the IBM 8RF process, a 0.13 {micro}m CMOS process. It was designed to operate with a 300MHz clock and has been tested up to 500MHz.

Brocato, Robert Wesley

2007-10-01

368

Femoral neck fracture fixation: rigidity of five techniques compared.  

PubMed Central

Artificial cadaveric femoral neck fractures were internally fixed with five different devices and subjected to cyclical loading of 0-1.0 kilonewtons (approximately one body weight) whilst in an anatomical position. Displacement of the proximal fragment was detected by a transducer and charted. Bone strength was assessed by a preliminary control loading phase on the intact bone. Efficiency of each fracture fixator could then be directly compared by the relative movement in each case. Five specimens each were tested with Moore's Pins, Trifin Nail, Garden Screws and a sliding screw-plate (OEC Ltd). By the criteria of the experiment, which put a severe shearing load on the implant, none of these devices reliably bore the representative body weight. An extended barrel-plate, which supported the sliding screw almost up to the fracture line, was then made. This device, employing some of Charnley's concepts, tolerated body weight in four cases out of five.

Mackechnie-Jarvis, A C

1983-01-01

369

Measuring the onset of locking in the Peru-Chile trench with GPS and acoustic measurements.  

PubMed

The subduction zone off the west coast of South America marks the convergence of the oceanic Nazca plate and the continental South America plate. Nazca-South America convergence over the past 23 million years has created the 6-km-deep Peru-Chile trench, 150 km offshore. High pressure between the plates creates a locked zone, leading to deformation of the overriding plate. The surface area of this locked zone is thought to control the magnitude of co-seismic release and is limited by pressure, temperature, sediment type and fluid content. Here we present seafloor deformation data from the submerged South America plate obtained from a combination of Global Positioning System (GPS) receivers and acoustic transponders. We estimate that the measured horizontal surface motion perpendicular to the trench is consistent with a model having no slip along the thrust fault between 2 and 40 km depth. A tsunami in 1996, 200 km north of our site, was interpreted as being the result of an anomalously shallow interplate earthquake. Seismic coupling at shallow depths, such as we observe, may explain why co-seismic events in the Peruvian subduction zone create large tsunamis. PMID:15758997

Gagnon, Katie; Chadwell, C David; Norabuena, Edmundo

2005-03-10

370

The in vivo performance of 250 internal fixation devices: a follow-up study.  

PubMed

The in vivo performance of 250 retrieved internal fixation plates was evaluated. The corrosion characteristics and metallurgical properties of each implant were assessed and correlated with respective clinical performance. Screw-plate interface corrosion and screw surface corrosion were graded; Rockwell hardness, grain size, thin inclusion content, and heavy inclusion content measurements were made. The devices studied included 169 bone plates, 59 Richards type hip screw-plates and 22 Jewett type hip nail-plates. The devices remained in situ for an average of 26.3 months, with in situ periods ranging from 1 to 192 months. The majority of the plates (50.4%) were removed due to cause-related reasons, while the remaining devices (49.6%) were removed on a routine asymptomatic basis. The primary symptomatic removal reasons consisted of implant related pain, nonunion or malunion, infection, loosening and implant breakage. Upon stereomicroscopic examination, 89% of all plates exhibited some degree of interface crevice corrosion, and 88% of all screws exhibited some degree of surface corrosion. Statistical analysis of corrosion gradings and metallurgical data revealed significant correlations between the two. As was suggested in our previous study of a limited number of implants, this study demonstrates that stricter manufacturing standards for metallurgical properties would serve to enhance corrosion resistance and improve the in vivo performance of stainless steel internal fixation devices. It is also suggested that the routine removal of all internal fixation plates after fracture healing has been achieved would reduce the occurrence of symptomatic complications, such as implant breakage, implant loosening and implant related pain. PMID:3607150

Cook, S D; Thomas, K A; Harding, A F; Collins, C L; Haddad, R J; Milicic, M; Fischer, W L

1987-05-01

371

In vitro biomechanical evaluation of sagittal split osteotomy fixation with a specifically designed miniplate.  

PubMed

Recent studies have evaluated many methods of internal fixation for sagittal split ramus osteotomy (SSRO), aiming to increase stability of the bone segments while minimizing condylar displacement. The purpose of this study was to evaluate, through biomechanical testing, the stability of the fixation comparing a specially designed bone plate to other two commonly used methods. Thirty hemimandibles were separated into three equal groups. All specimens received SSRO. In Group I the osteotomies were fixed with three 15 mm bicortical positional screws in an inverted-L pattern with an insertion angle of 90°. In Group II, fixation was carried out with a four-hole straight plate and four 6mm monocortical screws. In Group III, fixation was performed with an adjustable sagittal plate and eight 6mm monocortical screws. Hemimandibles were submitted to vertical compressive loads, by a mechanical testing unit. Averages and standard deviations were submitted to analysis of variance using the Tukey test with a 5% level of significance. Bicortical screws presented the greatest values of loading resistance. The adjustable miniplate demonstrated 60% lower resistance compared to bicortical screws. Group II presented on average 40% less resistant to the axial loading. PMID:22898312

Pereira Filho, V A; Iamashita, H Y; Monnazzi, M S; Gabrielli, M F R; Vaz, L G; Passeri, L A

2012-08-13

372

A new generation of lock and tag  

SciTech Connect

The safety culture of an organization needs to change to achieve full implementation of Chapter 9, Lockout and Tagouts'' of DOE Order 5480.19, Conduct of Operations Requirements for DOE Facilities (DOE 1990). You can implement this change of culture through Conduct of Operations training in the classroom, in organized group discussions, and with on-the-job training. In many facilities, lock and tag is viewed as an administration function that is not directly tied to individual employee safety. Often, lock and tag is seen as an obstacle to getting the job done, a roadblock in the way of progress that has been placed there by unseen forces for unknown reasons. Because lock and tag is not always viewed as part of the personal safety standards of the employee, the necessary attention to detail is lacking. We are presenting you with three useful methods for introducing and reinforcing a new generation of safety culture and lock and tag safety. The method will help your fellow workers view lock and tag and as a safety tool. Lock and tag will become part of their safety foundation. However, you may need to do some foundation building regarding safety, personal standards, and worker attitude before the principles of lock and tag training can become an integral part of your safety culture.

Wells, P.A.; Bickford, J.C.

1992-04-01

373

A new generation of lock and tag  

SciTech Connect

The safety culture of an organization needs to change to achieve full implementation of Chapter 9, ``Lockout and Tagouts`` of DOE Order 5480.19, Conduct of Operations Requirements for DOE Facilities (DOE 1990). You can implement this change of culture through Conduct of Operations training in the classroom, in organized group discussions, and with on-the-job training. In many facilities, lock and tag is viewed as an administration function that is not directly tied to individual employee safety. Often, lock and tag is seen as an obstacle to getting the job done, a roadblock in the way of progress that has been placed there by unseen forces for unknown reasons. Because lock and tag is not always viewed as part of the personal safety standards of the employee, the necessary attention to detail is lacking. We are presenting you with three useful methods for introducing and reinforcing a new generation of safety culture and lock and tag safety. The method will help your fellow workers view lock and tag and as a safety tool. Lock and tag will become part of their safety foundation. However, you may need to do some foundation building regarding safety, personal standards, and worker attitude before the principles of lock and tag training can become an integral part of your safety culture.

Wells, P.A.; Bickford, J.C.

1992-04-01

374

Dicondylar humeral fracture stabilisation in a dog using a transilial rod and external fixation.  

PubMed

Repair of a Salter-Harris type IV dicondylar humeral fracture was performed on a 15-week-old pitbull terrier. Interfragmentary compression of the intracondylar component of the fracture was achieved with a transilial rod and locking nuts (Trans-ilial Rod; IMEX Veterinary, Inc.). The transilial rod was articulated with a modified type I external fixator which functioned as adjunctive stabilisation for the supracondylar component of the fracture. Fracture healing was confirmed radiographically five weeks following surgery. The dog had no appreciable lameness when examined 12 months after fracture repair. PMID:17725586

Au, K; Mattern, K L; Lewis, D D

2007-08-23

375

Efficacy analysis of pedicle screw internal fixation of fractured vertebrae in the treatment of thoracolumbar fractures  

PubMed Central

The present study aimed to discuss the method and effect of posterior internal fixation of thoracolumbar fractures strengthened by the vertical stress pedicle screw fixation of fractured vertebrae. Patients with single thoracolumbar fractures were examined retrospectively. Fourteen patients (group A) had been treated with vertical stress pedicle screw fixation of a fractured vertebra and sixteen patients (group B) received traditional double-plate fixation, as a control. All patients were diagnosed with fresh fractures with a complete unilateral or bilateral pedicle and no explosion of the inferior half of the vertebral body or inferior endplate. In group A, patients received conventional posterior distraction and lumbar lordosis restoration, as well as pedicle screws in the fractured vertebra in a vertical direction to relieve stress to achieve a local stress balance. All patients were followed up postoperatively for 4–18 months (average, 12.6 months). The vertical stress pedicle screw fixation assisted in the reduction of vertebrae fracture, which reduced the postoperative Cobb’s angle loss. There was a significant difference in the change of Cobb’s angle between the two groups one year after surgery (P<0.01). Conditional application of pedicle screws in a single thoracolumbar fracture enhances the stability of the internal fixation system and is conducive to the correction of kyphosis and maintenance of the corrective effects.

HUANG, WEIJIE; LUO, TAO

2013-01-01

376

Surgical approaches for minimally invasive plate osteosynthesis in dogs.  

PubMed

Fracture stabilisation techniques continue to evolve and to provide approaches which minimise the iatrogenic trauma associated with surgery. Minimally invasive plate osteosynthesis (MIPO) is a recently described method of biological internal fixation performed by introducing a bone plate via small insertional incisions that are made remote to the fracture site. The plate is slid adjacent to the bone in an epiperiosteal tunnel connecting the two insertional incisions. Screws are placed in the plate through the insertional incisions or via additional stab incisions made over the holes in the plate. In this paper we describe the surgical approaches used to perform MIPO in humeral, radial, femoral and tibial fractures in dogs. We found that these approaches allowed safe insertion of the plate without grossly damaging neuro-vascular structures. Further studies are needed to evaluate the clinical outcome of MIPO in dogs. PMID:19597635

Pozzi, A; Lewis, D

2009-06-23

377

Passively Mode-Locked Raman Laser  

NASA Astrophysics Data System (ADS)

We report on the observation of a mode-locked laser generated with a crystalline whispering gallery mode resonator pumped with a continuous wave laser. Optical pumping of the resonator generates an optical frequency comb with phase locked components at the Raman offset of the resonator host material. Phase locking of the modes is confirmed via measurement of the radio-frequency beat note produced by the comb on a fast photodiode. Neither the conventional Kerr comb nor hyperparametric oscillation is observed when the comb is present. We present a theoretical explanation of the effect.

Liang, W.; Ilchenko, V. S.; Savchenkov, A. A.; Matsko, A. B.; Seidel, D.; Maleki, L.

2010-10-01

378

A possible nitrogen crisis for Archaean life due to reduced nitrogen fixation by lightning.  

PubMed

Nitrogen is an essential element for life and is often the limiting nutrient for terrestrial ecosystems. As most nitrogen is locked in the kinetically stable form, N2, in the Earth's atmosphere, processes that can fix N2 into biologically available forms-such as nitrate and ammonia-control the supply of nitrogen for organisms. On the early Earth, nitrogen is thought to have been fixed abiotically, as nitric oxide formed during lightning discharge. The advent of biological nitrogen fixation suggests that at some point the demand for fixed nitrogen exceeded the supply from abiotic sources, but the timing and causes of the onset of biological nitrogen fixation remain unclear. Here we report an experimental simulation of nitrogen fixation by lightning over a range of Hadean (4.5-3.8 Gyr ago) and Archaean (3.8-2.5 Gyr ago) atmospheric compositions, from predominantly carbon dioxide to predominantly dinitrogen (but always without oxygen). We infer that, as atmospheric CO2 decreased over the Archaean period, the production of nitric oxide from lightning discharge decreased by two orders of magnitude until about 2.2 Gyr. After this time, the rise in oxygen (or methane) concentrations probably initiated other abiotic sources of nitrogen. Although the temporary reduction in nitric oxide production may have lasted for only 100 Myr or less, this was potentially long enough to cause an ecological crisis that triggered the development of biological nitrogen fixation. PMID:11452304

Navarro-González, R; McKay, C P; Mvondo, D N

2001-07-01

379

View of lock while being filled through partially opened upper ...  

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

View of lock while being filled through partially opened upper lock gates, with control house on left and boats in lock, view towards southwest - St. Lucie Canal, St. Lucie Lock No. 1, St. Lucie, Cross State Canal, Okeechobee Intracoastal Waterway, Stuart, Martin County, FL

380

VIEW LOOKING EAST THROUGH LOCKS 69 AND 68. VIEW SHOWS ...  

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

VIEW LOOKING EAST THROUGH LOCKS 69 AND 68. VIEW SHOWS EXTANT GATE MOUNTING HARDWARE EMBEDED IN THE NORTH LOCK WALL, A FOOT BRIDGE SPANNING THE LOCK, THE MACHINE SHOP, AND THE ERIE CANAL MUSEUM (FORMER POWER PLANT). - New York State Barge Canal, Lockport Locks, Richmond Avenue, Lockport, Niagara County, NY

381

Resonance Assisted Synchronization of Coupled Oscillators: Frequency Locking without Phase Locking  

NASA Astrophysics Data System (ADS)

Frequency locking without phase locking of two coupled nonlinear oscillators is experimentally demonstrated. This synchronization regime is found for two coupled laser modes, beyond the phase-locking range fixed by Adler’s equation, because of a resonance mechanism. Specifically, we show that the amplitudes of the two modes exhibit strong fluctuations that produce average frequency synchronization, even if the instantaneous phases are unlocked. The experimental results are in good agreement with a theoretical model.

Thévenin, J.; Romanelli, M.; Vallet, M.; Brunel, M.; Erneux, T.

2011-09-01

382

Cable plates and onlay allografts in periprosthetic femoral fractures after hip replacement: laboratory and clinical observations.  

PubMed

Fractures of the femur after total hip replacement are an increasingly common and technically challenging problem. The results of nonsurgical treatment are poor. When the general condition of the patient allows, these injuries should be treated surgically. Several surgical treatments can be used to treat these fractures, and classification of the fracture assists the surgeon in the choice of procedure. Over the past decade, cable plate fixation systems and onlay strut allografts have become two of the most commonly used methods of fixation for fractures associated with hip prostheses. The ideal method of fixation is yet to be determined. However, laboratory studies have shown that dual fixation using either a lateral plate and anterior strut graft or two strut grafts produces the strongest construct. Cables rather than smooth wires should be used for fixation, and fixation strength increases with the number of cables used. The use of screws proximally produces a strong fixation but there are theoretical disadvantages to using screws around a femoral implant. Clinical data show high rates of fracture union using cable plate fixation, cortical onlay allograft fixation, and combined fixation methods for fractures that occur around well-fixed implants. Results have been less encouraging when these techniques have been used to fix fractures around prostheses that are either loose or malaligned; such fractures are better managed by revision of the femoral component to a long-stemmed device. Care should also be taken when there has been previous periosteal stripping of the femur because this may predispose to fracture nonunion. Periprosthetic fractures of the femur are a complex surgical problem and require specialized training in a range of surgical techniques. PMID:15116604

Howell, Jonathan R; Masri, Bassam A; Garbuz, Donald S; Greidanus, Nelson V; Duncan, Clive P

2004-01-01

383

An oculomotor continuum from exploration to fixation.  

PubMed

During visual exploration, saccadic eye movements scan the scene for objects of interest. During attempted fixation, the eyes are relatively still but often produce microsaccades. Saccadic rates during exploration are higher than those of microsaccades during fixation, reinforcing the classic view that exploration and fixation are two distinct oculomotor behaviors. An alternative model is that fixation and exploration are not dichotomous, but are instead two extremes of a functional continuum. Here, we measured the eye movements of human observers as they either fixed their gaze on a small spot or scanned natural scenes of varying sizes. As scene size diminished, so did saccade rates, until they were continuous with microsaccadic rates during fixation. Other saccadic properties varied as function of image size as well, forming a continuum with microsaccadic parameters during fixation. This saccadic continuum extended to nonrestrictive, ecological viewing conditions that allowed all types of saccades and fixation positions. Eye movement simulations moreover showed that a single model of oculomotor behavior can explain the saccadic continuum from exploration to fixation, for images of all sizes. These findings challenge the view that exploration and fixation are dichotomous, suggesting instead that visual fixation is functionally equivalent to visual exploration on a spatially focused scale. PMID:23533278

Otero-Millan, Jorge; Macknik, Stephen L; Langston, Rachel E; Martinez-Conde, Susana

2013-03-26

384

An oculomotor continuum from exploration to fixation  

PubMed Central

During visual exploration, saccadic eye movements scan the scene for objects of interest. During attempted fixation, the eyes are relatively still but often produce microsaccades. Saccadic rates during exploration are higher than those of microsaccades during fixation, reinforcing the classic view that exploration and fixation are two distinct oculomotor behaviors. An alternative model is that fixation and exploration are not dichotomous, but are instead two extremes of a functional continuum. Here, we measured the eye movements of human observers as they either fixed their gaze on a small spot or scanned natural scenes of varying sizes. As scene size diminished, so did saccade rates, until they were continuous with microsaccadic rates during fixation. Other saccadic properties varied as function of image size as well, forming a continuum with microsaccadic parameters during fixation. This saccadic continuum extended to nonrestrictive, ecological viewing conditions that allowed all types of saccades and fixation positions. Eye movement simulations moreover showed that a single model of oculomotor behavior can explain the saccadic continuum from exploration to fixation, for images of all sizes. These findings challenge the view that exploration and fixation are dichotomous, suggesting instead that visual fixation is functionally equivalent to visual exploration on a spatially focused scale.

Otero-Millan, Jorge; Macknik, Stephen L.; Langston, Rachel E.; Martinez-Conde, Susana

2013-01-01

385

Automatic NMR field-frequency lock-pulsed phase locked loop approach.  

PubMed

A self-contained deuterium frequency-field lock scheme for a high-resolution NMR spectrometer is described. It is based on phase locked loop techniques in which the free induction decay signal behaves as a voltage-controlled oscillator. By pulsing the spins at an offset frequency of a few hundred hertz and using a digital phase-frequency discriminator this method not only eliminates the usual phase, rf power, offset adjustments needed in conventional lock systems but also possesses the automatic pull-in characteristics that dispense with the use of field sweeps to locate the NMR line prior to closure of the lock loop. PMID:18699193

Kan, S; Gonord, P; Fan, M; Sauzade, M; Courtieu, J

1978-06-01

386

Locked modes in TEXT-U tokamak.  

National Technical Information Service (NTIS)

Locked mode coils for detecting radial magnetic field perturbations B(sub r) were recently constructed and installed on the TEXT-U tokamak. The measured experimental signals showed that both minor and major disruptive instabilities were almost always prec...

A. Vannucci S. C. McCool

1994-01-01

387

Drilling riser locking apparatus and method  

SciTech Connect

Apparatus and method for use in drilling a well from a floating vessel by means of a riser, which connects the vessels drilling equipment to a wellhead assembly adjacent the ocean floor. The riser is capable of being disconnected from the wellhead assembly, and having its upper elements locked to the vessel. This allows the riser to be suspended from the floating vessel, or permits maintenance of the normal riser motion-compensating and tensioning equipment. Riser locking apparatus is employed which comprises selectively positionable moveable locking beams adapted to be remotely actuated to lock the upper elements of the riser to the vessel, thereby preventing lateral or vertical movement of the riser relative to the vessel after the lower end thereof has been disconnected from the wellhead assembly.

Denison, E. B.

1985-10-08

388

Modeling of Magnetron Injection Locking Characteristics  

NASA Astrophysics Data System (ADS)

A magnetron-specific, phase-locking model has been developed [1] to qualitatively explain the various regimes observed in magnetron injection-locking experiments [2]. The experiments utilize two continuous wave oven magnetrons; one functions as an oscillator and the other as a driver. Both time and frequency domain solutions are developed from the model, allowing investigations into the growth and saturation as well as the frequency response of the output signal. This paper extends this locking theory for various configurations of magnetron coupling. Also studied is the general effect of driving frequency chirp on Adler's classical locking condition. This work was supported by AFOSR. [1] P. Penvanich et al., J. Appl. Phys. 98, 114903 (2005). [2] V. B. Neculaes, Ph.D. Dissertation, University of Michigan, Ann Arbor, MI (2005).

Pengvanich, P.; Lau, Y. Y.; Gilgenbach, R. M.; Luginsland, J. W.

2006-10-01

389

49 CFR 236.762 - Locking, indication.  

Code of Federal Regulations, 2010 CFR

...locking which prevents manipulation of levers that would result in an unsafe condition for a train movement if a signal, switch, or other operative...corresponding to that of its controlling lever, or which directly prevents...

2012-10-01

390

49 CFR 236.765 - Locking, mechanical.  

Code of Federal Regulations, 2011 CFR

...cross locking and other apparatus by means of which interlocking is effected between the levers of an interlocking machine and so interconnected that their movements must succeed each other in a predetermined...

2012-10-01

391

49 CFR 236.769 - Locking, traffic.  

Code of Federal Regulations, 2012 CFR

...traffic. Electric locking which prevents the manipulation of levers or other devices for changing the direction of traffic on...section is occupied or while a signal displays an aspect for a movement to proceed into that...

2012-10-01

392

Architectural Support for Fair Reader-Writer Locking  

Microsoft Academic Search

Many shared-memory parallel systems use lock-based synchronization mechanisms to provide mutual exclusion or reader-writer access to memory locations. Software locks are inefficient either in memory usage, lock transfer time, or both. Proposed hardware locking mechanisms are either too specific (for example, requiring static assignment of threads to cores and vice-versa), support a limited number of concurrent locks, require tag values

Enrique Vallejo; Ramon Beivide; Adrian Cristal; Tim Harris; Fernando Vallejo; Osman S. Unsal; Mateo Valero

2010-01-01

393

Primer on the Lock-in Amplifier  

NSDL National Science Digital Library

This is an experiment designed to measure the resistance of copper and gold nanowires using a lock-in amplifier. Students learn: 1. about different types of noise, 2. the principles of phase-sensitive techniques, 3. to extract signals buried in noise using a lock-in amplifier, 4. to operate optical chopper to measure weak optical signals modulated at a certain frequency. 4. to measure the minute resistance of a conducting nanowires.

Farooq, Sidra; Salman, Rabiya; Zia, Wasif; Hassan, Umer; Anwar, Muhammad S.

2012-02-10

394

Fourier domain mode locking pulse fiber laser  

Microsoft Academic Search

A novel pulse fiber laser is proposed based on the modulation of the lasing wavelength. Different from conventional amplitude\\u000a or phase modulated mode-locking fiber lasers, the proposed fiber laser is with a so-called Fourier domain mode locking (FDML)\\u000a operation (i.e., the cavity round-trip time of the optical pulse should match the period that the open time window of the\\u000a tunable

D. Chen

2010-01-01

395

Lock-Out / Tag-Out  

NSDL National Science Digital Library

Tags and locks can be the last line of defense against machinery accidents. This MATEC module leaves your learners solidly grounded in OSHA's six-step lockout/tagout procedures for preventing unexpected start-ups of equipment. They learn how to use energy-isolating devices and how to safely remove locks and tags. They can demonstrate their facility with the OHSA standards using a machine on the manufacturing floor.

2010-05-14

396

Treatment of periprosthetic femoral fractures with two different minimal invasive angle-stable plates: Biomechanical comparison studies on cadaveric bones  

Microsoft Academic Search

IntroductionThe introduction of fixed-angle plate osteosynthesis techniques has provided us a further means to treat periprosthetic femoral fractures. The goal of this experimental study is to evaluate the biomechanical properties and stability of treated periprosthetic fractures when using two different plate systems, which vary in the locking mechanism and the screw placement (monocortical or bicortical) with respect to the prosthesis

L. Konstantinidis; O. Hauschild; N. A. Beckmann; A. Hirschmüller; N. P. Südkamp; P. Helwig

397

Supplemental pinning improves the stability of external fixation in distal radius fractures during simulated finger and forearm motion.  

PubMed

External fixation is commonly used in the treatment of distal radius fractures. In this in vitro study, we investigated changes in fracture stability when using supplemental radial styloid pinning in combination with external fixation. Eight previously frozen cadaveric upper extremities were mounted in a computer-controlled wrist-loading apparatus. This device was used to generate finger and forearm motions through loading relevant tendons. An unstable extra-articular distal radius fracture was simulated by removing a dorsal wedge from the distal radius metaphysis. An electromagnetic tracking system measured fragment motion following randomized application of a Hoffman external fixator, a Hoffman external fixator with 2 supplemental radial styloid pins, and a dorsal 3.5-mm AO plate. Regardless of the fixation technique used in this unstable fracture model, fragment motion occurred when postoperative finger and forearm motions were simulated. The addition of radial styloid pins to a construct stabilized by an external fixator significantly improved fragment stability, approaching that achieved with the dorsal AO plate. PMID:10509278

Dunning, C E; Lindsay, C S; Bicknell, R T; Patterson, S D; Johnson, J A; King, G J

1999-09-01

398

Free fructose is conformationally locked.  

PubMed

Fructose has been examined under isolation conditions using a combination of UV ultrafast laser vaporization and Fourier-transform microwave (FT-MW) spectroscopy. The rotational spectra for the parent, all (six) monosubstituted (13)C species, and two single D species reveal unambiguously that the free hexoketose is conformationally locked in a single dominant ?-pyranose structure. This six-membered-chair skeleton adopts a (2)C(5) configuration (equivalent to (1)C(4) in aldoses). The free-molecule structure sharply contrasts with the furanose form observed in biochemically relevant polysaccharides, like sucrose. The structure of free fructose has been determined experimentally using substitution and effective structures. The enhanced stability of the observed conformation is primarily attributed to a cooperative network of five intramolecular O-H···O hydrogen bonds and stabilization of both endo and exo anomeric effects. Breaking a single intramolecular hydrogen bond destabilizes the free molecule by more than 10 kJ mol(-1). The structural results are compared to ribose, recently examined with rotational resolution, where six different conformations coexist with similar conformational energies. In addition, several DFT and ab initio methods and basis sets are benchmarked with the experimental data. PMID:23346993

Cocinero, Emilio J; Lesarri, Alberto; Écija, Patricia; Cimas, Álvaro; Davis, Benjamin G; Basterretxea, Francisco J; Fernández, José A; Castaño, Fernando

2013-02-07

399

Event-Locked Fourier Spectroscopy  

NASA Astrophysics Data System (ADS)

A new spectroscopic method for transient optical signals using a continuously scanning interferometer is described. Based on the interleaved (or stroboscopic) method, it achieves the same timing accuracy, signal-to-noise ratio, and freedom from artifacts as commercial step-scan interferometers by locking the interferogram digitization and optical-transient initiation to a quartz stable clock rather than to HeNe-laser fringe occurrences. Inevitable mirror-speed variations cause interferogram points to be recorded at unevenly spaced path-length differences, determined from a simultaneous speed record. Hence, a least-squares fit of harmonic functions extracts the spectrum rather than FFT. The method has low cost and fits any continuous scan FTIR. Our first implementation achieves time-resolved spectroscopy with 1 /mu s resolution. Spectroscopy of a low-duty-cycle FIR laser, a near-IR energy-transfer problem in a laser crystal, and a pulsed Ar-ion laser in the blue-green demonstrate the potential of the technique.

Weidner, Henry; Schwindt, C. J.; Peale, R. E.

1996-03-01

400

Intravascular lead extraction using locking stylets, sheaths, and other techniques.  

PubMed

Septicemia necessitates extraction of chronic pacemaker leads. Using locking stylets and sheaths to extract leads via the implantation vein (subclavian, cephalic, or jugular) and maneuvering devices, sheaths, and retrieval baskets via the femoral approach, extraction of 228 leads implanted 5 days to 240 months (mean 55 months) was attempted in 136 patients (mean 62 years) at 34 institutions. In addition to septicemia (9%) and infection (39%), total 48%, indications included prophylaxis/replacement (40%), and other (12%). Seventy-seven leads were atrial, 151 ventricular; 147 were unipolar, 81 bipolar; 96 had silicone insulation, 127 polyurethane, 1 poly/silicone, and 2 undetermined. Fixation included tines or fins (160), screw (40), flange (12), and other (16). One hundred and ninety-four leads were completely extracted, 19 partly extracted, and 15 not extracted. Procedural complications were: torn atrium requiring open heart repair (1), hemothorax requiring a chest tube and blood transfusions (1), subacute hemothorax requiring drainage 18 days after discharge (1), thrombosis treated by drugs (1), and myocardial avulsion without sequela (1). Important observations included the significant training required due to the large number of possible clinical variables, and the need to be prepared for life-threatening cardiovascular complications. With training, procedures done at higher volume and lower volume institutions met with similar success. Conclusion: Intravascular lead extraction is a viable technique whose benefits outweigh the risks, given the proper intensive training and open heart surgical backup, and may obviate the need for open heart surgery for lead extraction. PMID:1704556

Fearnot, N E; Smith, H J; Goode, L B; Byrd, C L; Wilkoff, B L; Sellers, T D

1990-12-01

401

Intravascular lead extraction using locking stylets and sheaths.  

PubMed

Chronic lead extraction using intravascular countertraction techniques was studied in patients with over 65 different lead models including passive and active fixation devices. Indications for removal of 115 leads implanted 5 days to 264 months (mean 58 months) in 62 patients (mean 65 years) included septicemia, subcutaneous tissue infection, preerosion, free-floating lead, lead trapped in valve, too many leads, pain, and vein thrombosis. The superior vena cava (SVC) approach was attempted in 101 leads and was successful in 82 attempts (71% of total leads). The inferior vena cava (IVC) approach via the femoral vein was required to extract 14 (12%) leads inaccessible to the SVC approach and the 19 leads that failed the SVC approach (29% of total leads). The SVC procedure includes a sized stylet locked at the tip and telescoping sheaths advanced over the lead to the heart. An IVC procedure includes placement of a 16 F sheath workstation via a femoral vein into the right atrium. A deflection catheter and Dotter snare in an 11 F sheath were advanced through the workstation into the right atrium. The lead was maneuvered into position, snared, and pulled into the workstation. For both the SVC and IVC approaches, the leads were removed by applying traction on the lead and countertraction with the sheaths. In experienced hands, these techniques have proven safe and effective for removing chronic transvenous leads. PMID:1704557

Byrd, C L; Schwartz, S J; Hedin, N B; Goode, L B; Fearnot, N E; Smith, H J

1990-12-01

402

Intramedullary foot fixation for midfoot Charcot neuroarthropathy.  

PubMed

Midfoot Charcot collapse commonly occurs through the tarsometatarsal and/or midtarsal joints, which creates the characteristic "rocker bottom" deformity. Intramedullary metatarsal fixation spanning the tarsus into the talus and/or calcaneus is a recently developed method for addressing unstable midfoot Charcot deformity. The intramedullary foot fixation technique has various advantages when addressing midfoot Charcot deformity in the neuropathic patient. These advantages include anatomical realignment, minimally invasive fixation technique, formal multiple joint fusion, adjacent joint fixation beyond the level of Charcot collapse, rigid interosseus fixation, and preservation of foot length. The goals of the intramedullary foot fixation procedure are to create a stable, plantigrade, and ulcer-free foot, which allows the patient to ambulate with custom-molded orthotics and shoes. PMID:22632840

Lamm, Bradley M; Siddiqui, Noman A; Nair, Ajitha K; LaPorta, Guido

2012-05-24

403

The Biggest Plates on Earth: Plate Tectonics  

NSDL National Science Digital Library

In this lesson, students investigate the movement of Earth's tectonic plates, the results of these movements, and how magnetic anomalies present at spreading centers document the motion of the crust. As a result of this activity, students will be able to describe the motion of tectonic plates, differentiate between three types of plate boundaries, infer what type of boundary exists between two tectonic plates, and understand how magnetic anomalies provide a record of geologic history and crustal motion around spreading centers. As an example, they will also describe plate boundaries and tectonic activity in the vicinity of the Juan de Fuca plate adjacent to the Pacific Northwest coast of North America.

404

Strength of internal fixation for calcaneal fractures  

Microsoft Academic Search

Objective. To compare the strength of two types of fixation method for calcaneal fractures.Design. A biomechanical testing examined the stability of 12 fractured calcaneal specimens fixed with two different methods.Background. Though anatomic reduction and internal fixation for the treatment of intra-articular fractures of the calcaneus has become popular, biomechanical data on the fixation strength is lacking.Methods. Twenty fresh frozen specimens

Chung-Li Wang; Guan-Liang Chang; Wen-Chang Tseng; Chin-Yin Yu; Ruey-Mo Lin

1998-01-01

405

Intermittent Plate Tectonics  

Microsoft Academic Search

Intermittent Plate Tectonics A basic premise of Earth Science is that plate tectonics has been continuously operating since it began early in Earth's history. Yet, plate-tectonic theory itself, specifically the collisional phase of the Wilson Cycle, constitutes a process that is capable of stopping all plate motion. The plausibility of a plate-tectonic hiatus is most easily illustrated by considering the

P. G. Silver; M. D. Behn

2006-01-01

406

Petrology and plate tectonics  

Microsoft Academic Search

Petrology played an important role in the formulation of plate tectonics and early plate tectonic interpretations of the geologic past. In the last few years widespread interest in plate tectonics and progress in plate tectonic interpretations have begun to give petrology various feedback effects.In the period 1971–1974 there were two symposiums intended particularly to connect petrology with plate tectonics [Wyllie,

Akiho Miyashiro

1975-01-01

407

Karnovsky-osmium as a primary fixative for electron microscopy  

NASA Astrophysics Data System (ADS)

A combined Karnovsky-osmium tetroxide primary fixative is proposed for transmission electron microscopy. This fixative, hypothetically, seems to overcome the drawbacks of sequential fixation techniques. Evaluation of this combined fixative reveals very acceptable fixation of hepatocytes, lymphocytes, and fibroblasts, as well as various organelles within these cells.

Buchanan, G. M.

1983-09-01

408

Environmentally safe parasitology fixative and stain  

US Patent & Trademark Office Database

A fixative-stain system, which gives superior preservation of nuclear detail, is free from toxic mercury compounds, and which is simple and easy to use, includes a zinc salt and a cobalt salt, in combination, as a fixative, and at least one of Chlorazol Black E, Fast Green FCF and May-Grunwald stains, and preferably the three in admixture, as a staining composition. The fixative may also be used alone. The present fixative-stain system is suitable for fixing and staining all types of parasites such as enteric and other parasites which infect animals and humans.

1996-04-16

409

Modeling fixation locations using spatial point processes.  

PubMed

Whenever eye movements are measured, a central part of the analysis has to do with where subjects fixate and why they fixated where they fixated. To a first approximation, a set of fixations can be viewed as a set of points in space; this implies that fixations are spatial data and that the analysis of fixation locations can be beneficially thought of as a spatial statistics problem. We argue that thinking of fixation locations as arising from point processes is a very fruitful framework for eye-movement data, helping turn qualitative questions into quantitative ones. We provide a tutorial introduction to some of the main ideas of the field of spatial statistics, focusing especially on spatial Poisson processes. We show how point processes help relate image properties to fixation locations. In particular we show how point processes naturally express the idea that image features' predictability for fixations may vary from one image to another. We review other methods of analysis used in the literature, show how they relate to point process theory, and argue that thinking in terms of point processes substantially extends the range of analyses that can be performed and clarify their interpretation. PMID:24084942

Barthelmé, Simon; Trukenbrod, Hans; Engbert, Ralf; Wichmann, Felix

2013-10-01

410

Research on CFRP materials nondestructive testing by IR lock-in thermography  

NASA Astrophysics Data System (ADS)

Lock-in thermography which is an active thermography technique for NDT is based on propagation and reflection of thermal waves which are launched from the surface into the inspected component by absorption of modulated radiation. Phase angle images obtained by superposition of the initial thermal wave and its internal reflection display hidden thermal structures down to a certain depth below surface. Defects are found by comparing the observed features with expected features provided by an intact reference sample. This technique has been widely applied to detect the defection of many materials and structure in aerospace and automotive industry. In this study, the law of sine modulated lamp was used for active heat source into the CFRP plate sample. The theory of thermal wave transmission and reflection were studied deeply by finite difference method and thermal-electronic equaling model. The thermal wave image sequences were collected with infrared camera, and the program of IR Lock-in thermography was developed by Visual C++ development platform. So that the phase image was extracted between the reflection thermal wave and reference ones on the surface of sample by means of correlation algorithms or Fourier transform. The experimental results show that the simulation is closed to the experimental ones. The defect character is detected clearly, and the relation between phase and defect depth is obtained by lock-in thermography, this relation can be used to measure the defect depth. Lock-in thermography is an effective tool to detect the Debonding defect of CFRP materials.

Liu, Junyan; Wang, Yang; Liu, Hui; He, Yinhang

2009-07-01

411

Arthroscopy-assisted fracture fixation  

Microsoft Academic Search

Purpose  The purpose of this article was to systematically analyze the results of published studies in the literature which evaluated\\u000a the use of arthroscopically assisted techniques in intra-articular fracture fixation.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Published investigations to date were analyzed by classifying them according to joints that were involved with intra-articular\\u000a fractures including: knee, ankle, hip, shoulder, elbow, and wrist joints. The results were studied

Kivanc AtesokM; M. Nedim Doral; Terry Whipple; Gideon Mann; Omer Mei-Dan; O. Ahmet Atay; Yiftah Beer; Joseph Lowe; Michael Soudry; Emil H. Schemitsch

2011-01-01

412

49 CFR 236.340 - Electromechanical interlocking machine; locking between electrical and mechanical levers.  

Code of Federal Regulations, 2012 CFR

...false Electromechanical interlocking machine; locking between electrical and mechanical...340 Electromechanical interlocking machine; locking between electrical and mechanical... In electro-mechanical interlocking machine, locking between electric and...

2012-10-01

413

49 CFR 236.340 - Electromechanical interlocking machine; locking between electrical and mechanical levers.  

Code of Federal Regulations, 2011 CFR

...false Electromechanical interlocking machine; locking between electrical and mechanical...340 Electromechanical interlocking machine; locking between electrical and mechanical... In electro-mechanical interlocking machine, locking between electric and...

2011-10-01

414

Do Fixation Cues Ensure Fixation Accuracy in Split-Fovea Studies of Word Recognition?  

ERIC Educational Resources Information Center

Many studies have claimed that hemispheric processing is split precisely at the foveal midline and so place great emphasis on the precise location at which words are fixated. These claims are based on experiments in which a variety of fixation procedures were used to ensure fixation accuracy but the effectiveness of these procedures is unclear. We…

Jordan, Timothy R.; Paterson, Kevin B.; Kurtev, Stoyan; Xu, Mengyun

2009-01-01

415

Plate Tectonics: Consequences of Plate Interactions  

NSDL National Science Digital Library

This Science Object is the fourth of five Science Objects in the Plate Tectonic SciPack. It identifies the events that may occur and landscapes that form as a result of different plate interactions. The areas along plate margins are active. Plates pushing against one another can cause earthquakes, volcanoes, mountain formation, and very deep ocean trenches. Plates pulling apart from one another can cause smaller earthquakes, magma rising to the surface, volcanoes, and oceanic valleys and mountains from sea-floor spreading. Plates sliding past one another can cause earthquakes and rock deformation. Learning Outcomes:� Explain why volcanoes and earthquakes occur along plate boundaries. � Explain how new sea floor is created and destroyed.� Describe features that may be seen on the surface as a result of plate interactions.

National Science Teachers Association (NSTA)

2006-11-01

416

Modeling of mode-locked fiber lasers  

NASA Astrophysics Data System (ADS)

This thesis presents the results of analytical and numerical simulations of mode-locked fiber lasers and their components: multiple quantum well saturable absorbers and nonlinear optical loop mirrors. Due to the growing interest in fiber lasers as a compact source of ultrashort pulses there is a need to develop a full understanding of the advantages and limitations of the different mode-locked techniques. The mode-locked fiber laser study performed in this thesis can be used to optimize the design and performance of mode-locked fiber laser systems. A group at Air Force Research Laboratory reported a fiber laser mode-locked by multiple quantum well (MQW) saturable absorber with stable pulses generated as short as 2 ps [21]. The laser cavity incorporates a chirped fiber Bragg grating as a dispersion element; our analysis showed that the laser operates in the soliton regime. Soliton perturbation theory was applied and conditions for stable pulse operation were investigated. Properties of MQW saturable absorbers and their effect on cavity dynamics were studied and the cases of fast and slow saturable absorbers were considered. Analytical and numerical results are in a good agreement with experimental data. In the case of the laser cavity with a regular fiber Bragg grating, the properties of MQW saturable absorbers dominate the cavity dynamics. It was shown that despite the lack of a soliton shaping mechanism, there is a regime in parameter space where stable or quasi-stable solitary waves solutions can exist. Further a novel technique of fiber laser mode-locking by nonlinear polarization rotation was proposed. Polarization rotation of vector solitons was simulated in a birefringent nonlinear optical loop mirror (NOLM) and the switching characteristics of this device was studied. It was shown that saturable absorber-like action of NOLM allows mode-locked operation of the two fiber laser designs. Laser cavity designs were proposed: figure-eight-type and sigma-type cavity.

Shaulov, Gary

417

High-performance phase locking of wide linewidth semiconductor lasers by combined use of optical injection locking and optical phase-lock loop  

Microsoft Academic Search

The requirement for narrow linewidth lasers or short-loop propagation delay makes the realization of optical phase-lock loops using semiconductor lasers difficult. Although optical injection locking can provide low phase error variance for wide linewidth lasers, the locking range is restricted by stability considerations. Theoretical and experimental results for a system which combines both techniques so as to overcome these limitations,

A. C. Bordonalli; C. Walton; Alwyn J. Seeds

1999-01-01

418

[Primary stability of AO-plate osteosynthesis of the lower cervical spinal column. III. Posterior and combined spondylodesis. Conclusions].  

PubMed

For evaluation of stability changes-concerning primary stability of the lower cervical spine either posterior ASIF plate fixation according to Roy-Camille or combined fixation (anterior H plate and posterior plate fixation according to Roy-Camille) were performed for arteficially produced fracture-dislocations of the lower cervical spine on cadavers. Functional loading was simulated by a mechanical device ensuring 10 000 flexion and extension movements on the corpses. Tensile moments determined by a screwdriver measuring the turning moment were compared with the release moment examined on screws following functional loading, unloaded free screws were used as reference. Decreasing of stability depending on the type of the injury has come posteriorly to 2,52-18,65%, anteriorly to 0,57-20% of the primary rate. It has been established that external fixation is not warranted in the postoperative treatment of patients with fracture dislocations of the lower cervical spine following either ASIF plate fixation according to Roy-Camille or combined plate fixation. General rules of the operative fracture management are valid for treatment of the cervical spine built of segmental elements. PMID:4002764

Sándor, L

1985-01-01

419

Pneumatic wall-locking geophone system  

DOEpatents

A seismic signal receiving system is provided for use in boreholes to receive seismic waves in carrying out geophysical investigations. The system includes three pairs of opposed plates, each of the pairs of plates including oppositely facing outer surfaces for engagement with opposite sides of a borehole. A seismic receiver is mounted on the inner surface of each of the plates for receiving seismic signals. A double-acting, fluid-operated actuator selectively causes relative movement of the plates of the pairs of plates away from each other to provide expansion thereof so as to enable the plates to engage the walls of a borehole and selectively causes relative movement of the plates of the pairs of plates toward each other to provide retraction thereof so as to enable the system to be removed from a borehole. The pairs of plates each comprise a relatively long plate and a relatively short plate. An expandable linkage interconnects the long plates at the distal ends thereof. The plates are mechanically biassed into the retracted state so that the plates return to this state in the event of a system failure.

Kuhlman, Harland L. (Minneapolis, MN); Cumerlato, Calvin L. (Minneapolis, MN); Tweeton, Daryl R. (Apple Valley, MN)

1991-01-01

420

Hamate hook nonunion treated with a hook plate: case report and surgical technique.  

PubMed

Despite of its rarity, hamate hook nonunion can cause several complications like tendon rupture or loss of grip strength. Admitted treatments in the literature are excision of the bone fragment or its open reduction and internal fixation. We report a clinical case of a high-level baseball player with hamate hook nonunion treated with an original technique of fixation using a hook plate. PMID:23160549

Taleb, Chihab; Murachowsky, Joel; Ruggiero, Gustavo M

2012-12-01

421

The nature of the plate interface and driving force of interseismic deformation in the New Zealand plate-boundary zone, revealed by the continuous GPS velocity field  

NASA Astrophysics Data System (ADS)

New Zealand straddles the boundary between the Australian and Pacific plates. Cenozoic relative plate motion has resulted in a complex pattern of faulting and block rotation, with displacements on individual faults up to hundreds of kilometers. However, over periods of several years, GPS measurements show a remarkably smooth pattern of velocities. We show here using a new method of back slip analysis, that almost the entire plate-boundary continuous GPS velocity field can be predicted within measurement error from a simple model of elastic distortion due to deep slip on a single plate interface (megathrust in the Hikurangi and Putsegur subduction zones or fault through continental lithosphere beneath the Southern Alps) at the relative plate motion rates. This suggests that the main driving force of plate-boundary deformation is slip on the deeper moving part of the plate interface, without buried creep in localized shear zones beneath individual surface faults. The depth at which this deep slip terminates (locking point line) determines the width of deformation. Along the Hikurangi margin, there is also clockwise rotation of ~150 km long segment of the fore arc (Wairoa domain) at 4.5° ± 1 Ma, relative to the Australian Plate, about a pole in western North Island; model residuals in the velocity field are mainly a result of incomplete averaging of the cycle of slow slip events on the plate interface, downdip of the locking point.

Lamb, Simon; Smith, Euan

2013-06-01

422

21 CFR 872.4880 - Intraosseous fixation screw or wire.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Intraosseous fixation screw or wire. 872.4880 Section 872... § 872.4880 Intraosseous fixation screw or wire. (a) Identification. An intraosseous fixation screw or wire is a metal device intended...

2010-04-01

423

21 CFR 872.4880 - Intraosseous fixation screw or wire.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Intraosseous fixation screw or wire. 872.4880 Section 872... § 872.4880 Intraosseous fixation screw or wire. (a) Identification. An intraosseous fixation screw or wire is a metal device intended...

2009-04-01

424

Bending deformations of plates in the model of strong subduction earthquakes  

NASA Astrophysics Data System (ADS)

The model of elastic rebound of thin plates is considered to account for GPS-inferred surface deformation of plates during subduction earthquakes on the example of the M9 earthquake that occurred in Japan in 2011. Due to the fact that the oceanic plate moves together with a great mass of the convective mantle, it dips into the mantle at constant velocity all the time, both during the earthquakes and in the periods between them, although its coupling with the continental plate changes. The edge of the continental plate behaves as an elastic plate that permanently bends under the action of the friction force on contact with the diving oceanic plate. The bent plate unbends after the earthquake. This leads to its thrusting over the subducting oceanic plate. As a result, the island plate moves towards the ocean, its island part sinks, and the oceanic plate uplifts leading to a tsunami. The coordinates and magnitudes of the rise and subsidence correspond to the universal relations in the elastic plate model. The breaking of coupling of the continental plate with the submarine mountains and a basaltic plateau of the dipping plate is considered as a possible explanation of the anomalous properties of the strongest earthquakes. The main earthquake can be produced by partial destruction of a plateau or a large mountain. After this, the locked plates become free along a great area in an avalanche-like manner, and the friction of rest gives place to sliding friction.

Trubitsyn, V. P.

2012-02-01

425

Evaluation of the syndesmotic-only fixation for Weber-C ankle fractures with syndesmotic injury  

PubMed Central

Background: With the length of the fibula restored and the syndesmosis reduced anatomically, internal fixation using a plating device may not be necessary for supra-syndesmotic fibular fractures combined with diastasis of inferior tibio-fibular joint. A retrospective observational study was performed in patients who had this injury pattern treated with syndesmosis-only fixation. Materials and Methods: 12 patients who had Weber type-C injury pattern were treated with syndesmosis only fixation. The treatment plan was followed only if the fibular length could be restored and if the syndesmosis could be anatomically reduced. Through a percutaneous or mini-open reduction and clamp stabilization of the syndesmosis, all but one patient had a single tricortical screw fixation across the syndesmosis. Patients were kept non-weight-bearing for 6 weeks, followed by screw removal at an average of 8 weeks. Outcomes were assessed using an objective ankle scoring system (Olerud and Molander scale) and by radiographic assessment of the ankle mortise. Results: At a mean follow-up of 13 months, the functional outcome score was 75. Excellent to good outcomes were noted in 83% of the patients. Ankle mortise was reduced in all cases, and all but one fibular fracture united without loss of fixation. Six patients had more than one malleolar injury, needing either screw or anchor fixations. One patient had late diastasis after removal of the syndesmotic screw and underwent revision surgery with bone grafting of the fibula. This was probably due to early screw removal, before union of the fibular fracture had occurred. Conclusion: We recommend syndesmosis-only fixation as an effective treatment option for a combination of syndesmosis disruption and Weber type-C lateral malleolar fractures.

Mohammed, R; Syed, S; Metikala, S; Ali, SA

2011-01-01

426

Chemical fixation of arsenic in contaminated soils  

Microsoft Academic Search

Arsenic-contaminated soils have been successfully treated using fixation methods whereby chemicals are added to prevent As mobilization. However, the chemistry of the fixation process used in the field is poorly understood. We have examined one process which succeeded in immobilizing 0. I to 0.2 weight % As in soil at a 69 a old dump site through the addition of

Remy J.-C. Hennet; S. L. Brantley

1996-01-01

427

Nitrogen Fixation in Denitrified Marine Waters  

Microsoft Academic Search

Nitrogen fixation is an essential process that biologically transforms atmospheric dinitrogen gas to ammonia, therefore compensating for nitrogen losses occurring via denitrification and anammox. Currently, inputs and losses of nitrogen to the ocean resulting from these processes are thought to be spatially separated: nitrogen fixation takes place primarily in open ocean environments (mainly through diazotrophic cyanobacteria), whereas nitrogen losses occur

Camila Fernandez; Laura Farías; Osvaldo Ulloa

2011-01-01

428

Fixation and the Road Not Taken  

Microsoft Academic Search

In this article, the psychic and existential impact that fixation has on an individual's life is addressed. A person may drift through years that are dictated by the circuitous path of a fixation and its vicissitude of the repetition compulsion. When such \\

Peter Shabad

1987-01-01

429

Direct needle fixation in endoscopic facial rejuvenation  

Microsoft Academic Search

Background: Several authors have described the application of video endoscopy to facial rejuvenation to minimize incisions. Methods of fixation used in this technique include miniplates, tunnels in the outer tissues, and tissue glues. Objective: In this study, we examined the efficacy of endoscopic facial rejuvenation with direct transcutaneous needle fixation. Methods: Detailed preoperative markings were placed to outline important anatomical

Carlos Casagrande; Renato Saltz; Roberto Chem; Rinaldo Pinto; Marcus Collares

2000-01-01

430

Two fixations suffice in face recognition.  

PubMed

It is well known that there exist preferred landing positions for eye fixations in visual word recognition. However, the existence of preferred landing positions in face recognition is less well established. It is also unknown how many fixations are required to recognize a face. To investigate these questions, we recorded eye movements during face recognition. During an otherwise standard face-recognition task, subjects were allowed a variable number of fixations before the stimulus was masked. We found that optimal recognition performance is achieved with two fixations; performance does not improve with additional fixations. The distribution of the first fixation is just to the left of the center of the nose, and that of the second fixation is around the center of the nose. Thus, these appear to be the preferred landing positions for face recognition. Furthermore, the fixations made during face learning differ in location from those made during face recognition and are also more variable in duration; this suggests that different strategies are used for face learning and face recognition. PMID:19000210

Hsiao, Janet Hui-wen; Cottrell, Garrison

2008-10-01

431

Spherical Retinal Flow for a Fixating Observer.  

National Technical Information Service (NTIS)

When a human observer moves, the eye continually fixates on targets in the world. Although fixation is a common process in human vision, its role has not yet been established for computational purposes. The main contribution of this paper is the formalize...

I. Thomas E. Simoncelli R. Bajcsy

1994-01-01

432

Biochemical Approaches to Improved Nitrogen Fixation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Improving symbiotic nitrogen fixation by legumes has emerged again as an important topic on the world scene due to the energy crisis and lack of access to nitrogen fertilizer in developing countries. We have taken a biochemical genomics approach to improving symbiotic nitrogen fixation in legumes. L...

433

Driver Eye Fixations under Different Operating Conditions.  

National Technical Information Service (NTIS)

The eye fixations of six individuals were measured while driving on straight and curved sections of road, night and day, and with and without a car in front of them. Eye fixations on straight sections were distributed uniformly over the road, while on cur...

P. L. Olson D. S. Battle T. Aoki

1989-01-01

434

The osmotic effects of electron microscope fixatives.  

PubMed

The reflecting cells on the scales of sprat and herring contain ordered arrays of guanine crystals. The spacing of the crystals within these cells determines the wave bands of the light which they reflect, hence volume changes in the reflecting cells can be observed as color changes directly. This property of the scales is used to show that (a) fixation with osmium tetroxide solutions destroys osmotic activity; (b) fixation with aldehyde solutions does not destroy osmotic activity and does not cause volume changes if the aldehydes are made up in salt or sucrose solutions whose osmolarities, discounting the aldehyde, are about 60% of those to which the cells are in equilibrium in life, and (c) after aldehyde fixation the cells are osmotically active but come to a given volume in salt and sucrose solutions of concentrations only 60% of those which give their volume before fixation. Various possible mechanisms underlying the change of osmotic equilibrium caused by aldehyde fixation are discussed. PMID:4103952

Bone, Q; Denton, E J

1971-06-01

435

Arthroscopic coracoclavicular ligament reconstruction using biologic and suture fixation.  

PubMed

Presented in this report is a modified arthroscopic approach to acromioclavicular joint reconstruction via suture and allograft fixation. An arthroscopic approach is used to expose the base of the coracoid by use of electrocautery. After an open distal clavicle excision is performed, clavicular and coracoid tunnels are created under arthroscopic visualization as previously described by Wolf and Pennington. The myotendinous end of a semitendinosus allograft is sutured to a Spider plate (Kinetikos Medical, San Diego, CA). The tendinous end of the graft is prepared with a running baseball stitch. A Nitinol wire with a loop end (Arthrex, Naples, FL) is used to pass 2 free FiberTape sutures (Arthrex) and the leading sutures from the tendinous end of the graft through the clavicular and coracoid tunnels, exiting out the anterior portal. One of the FiberTape sutures is retrieved with a grasper and passed over the anterior aspect of the distal clavicle. The second FiberTape suture and the allograft are passed over the distal end of the resected clavicle. While the acromioclavicular joint is held reduced, the FiberTape sutures are tied to the plate and the allograft is tensioned medially until the plate is embedded against the superior surface of the clavicle. The tendinous end of the graft is secured to the superior surface of the clavicle with a Bio-tenodesis screw (Arthrex) medial to the clavicular tunnel. PMID:17637416

Pennington, William T; Hergan, David J; Bartz, Brian A

2007-02-14

436

Cervical Post-traumatic Unilateral Locked Facets: Clinical, Radiological and Surgical Remarks on a Series of 33 Patients.  

PubMed

STUDY DESIGN:: Radiographic and clinical analysis. OBJECTIVE:: Review author's experience with anterior discectomy, interbody fusion and anterior cervical plating in 33 patients with post-traumatic unilateral cervical locked facets. SUMMARY OF BACKGROUND DATA:: Unilateral cervical locked facet syndrome is a relatively uncommon injury that often is misdiagnosed and therefore subject to a dangerous delay in surgery. Management of this trauma is controversial. METHODS:: 33 patients with radiologically proven diagnosis of postraumatic unilateral cervical locked facets were treated by skull traction and surgical operation from January 2005 to December 2009. All patients preoperatively were assessed for neurological examination and underwent XRays, MRI and CT evaluation of the cervical spine. RESULTS:: The unilateral locked facet level was C4-C5 in 13 patients, C5-C6 in ten, C6-C7 in eight and C3-C4 in two patients. After closed reduction attempt with Crutchfield system, the correct alignment was achieved in 30 patients, who underwent anterior discectomy with cage, interbody fusion and anterior cervical plating. In 3 patients there was an overdistraction and therefore a closed reduction was not possible, so they were firstly operated by posterior approach with opened reduction of the facets, lateral mass screws and posterolateral fusion. In two of these patients there was an anterior fragment of the disc in the canal, so was also performed an anterior approach with discectomy, cage and plating. There were no surgery-related complications. Post-operative neurological status was unchanged in the three patients with tetraplegia and improved in eight of the ten patients with radiculopathy. Fusion was obtained in all patients, as showed in the clinical and radiological follow-up. CONCLUSION:: The authors conclude that an anterior approach provides a safe and effective alternative for the treatment of patients with post-traumatic unilateral cervical locked facet, when preoperatively the cervical alignment of the dislocation is achieved with a closed reduction. PMID:23429304

Piccirilli, Manolo; Liberati, Chiara; Santoro, Giorgio; Santoro, Antonio

2013-02-19

437

Mode-locked ytterbium fiber lasers.  

PubMed

A compact fiber laser is demonstrated with use of a Gires-Tournois compensator and a short length (2-4 cm-long) of highly doped ytterbium (Yb) fiber providing net anomalous group-velocity dispersion. With use of a novel semiconductor saturable absorber mirror based on GaInNAs structure, self-started 1.5-ps-pulse mode-locked operation was obtained at 1023 nm with a repetition rate of 95 MHz. A mode-locked Yb-doped fiber laser was developed without the use of any dispersion compensation technique. Overall group-velocity dispersion was minimized by using a short length of highly doped Yb fiber in a compact amplifying loop cavity. Self-started mode-locked operation was obtained in 980-1030-nm wavelength range with a fundamental repetition rate of 140 MHz. PMID:15065719

Orsila, Lasse; Gomes, Luís A; Xiang, Ning; Jouhti, Tomi; Okhotnikov, Oleg G

2004-03-20

438

Dynamics of phase-locking random lasers  

NASA Astrophysics Data System (ADS)

Laser modes may coalesce into a mode-locked state that enables femtosecond pulse compression. The nature of the interaction and the interaction time play fundamental roles in the onset of this collective state, but the investigation of the transition dynamics is technically challenging because phases are not always experimentally accessible. This is even more difficult for random lasers, a kind of disordered laser in which energies in play are much smaller than in the ordered macroscopic case. Here we investigate experimentally and numerically the dynamics of the phase-locking transition in a random laser. We developed an experimental setup able to pump individual modes with different pulse durations and found that the mode-locked regime builds only for quasicontinuous pumping, resulting in an emission linewidth dependent on the pump duration. Numerical simulation confirms experimental data.

Leonetti, Marco; Conti, Claudio; López, Cefe

2013-10-01

439