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1

Devices and methods for interlocking surgical screws and nails  

US Patent & Trademark Office Database

The present invention demonstrates an improved interlocking nail and screw combination to repair fracture bones. The preferred combination uses an hourglass shaped intramedullary nail wherein the larger ends of the nail have holes capable of receiving screws. The holes may, or may not be conical. Further, the holes may or may not be threaded. The surgical screws have a variety of thread patterns, or lack threads. A non-threaded end is believed to improve healing because of a larger core diameter as compared to a comparably sized threaded screw end.

2013-05-07

2

Interlocking medullary nails — Radiation doses in distal targeting  

Microsoft Academic Search

Distal interlocking of intramedullary nails involves the use of a fluoroscope and a targeting device. A specially designed awl makes the interlocking procedure simple and efficient. The 30-cm-long side arm of this awl protects the surgeon's hand from direct radiation, and measurements of X-ray exposure show that the protection against radiation is sufficient.

S. Skjeldal; S. Backe

1987-01-01

3

Reinforcing the role of the conventional C-arm - a novel method for simplified distal interlocking  

PubMed Central

Background The common practice for insertion of distal locking screws of intramedullary nails is a freehand technique under fluoroscopic control. The process is technically demanding, time-consuming and afflicted to considerable radiation exposure of the patient and the surgical personnel. A new concept is introduced utilizing information from within conventional radiographic images to help accurately guide the surgeon to place the interlocking bolt into the interlocking hole. The newly developed technique was compared to conventional freehand in an operating room (OR) like setting on human cadaveric lower legs in terms of operating time and radiation exposure. Methods The proposed concept (guided freehand), generally based on the freehand gold standard, additionally guides the surgeon by means of visible landmarks projected into the C-arm image. A computer program plans the correct drilling trajectory by processing the lens-shaped hole projections of the interlocking holes from a single image. Holes can be drilled by visually aligning the drill to the planned trajectory. Besides a conventional C-arm, no additional tracking or navigation equipment is required. Ten fresh frozen human below-knee specimens were instrumented with an Expert Tibial Nail (Synthes GmbH, Switzerland). The implants were distally locked by performing the newly proposed technique as well as the conventional freehand technique on each specimen. An orthopedic resident surgeon inserted four distal screws per procedure. Operating time, number of images and radiation time were recorded and statistically compared between interlocking techniques using non-parametric tests. Results A 58% reduction in number of taken images per screw was found for the guided freehand technique (7.4 ± 3.4) (mean ± SD) compared to the freehand technique (17.6 ± 10.3) (p < 0.001). Total radiation time (all 4 screws) was 55% lower for the guided freehand technique compared to conventional freehand (p = 0.001). Operating time per screw (from first shot to screw tightened) was on average 22% reduced by guided freehand (p = 0.018). Conclusions In an experimental setting, the newly developed guided freehand technique for distal interlocking has proven to markedly reduce radiation exposure when compared to the conventional freehand technique. The method utilizes established clinical workflows and does not require cost intensive add-on devices or extensive training. The underlying principle carries potential to assist implant positioning in numerous other applications within orthopedics and trauma from screw insertions to placement of plates, nails or prostheses.

2012-01-01

4

[Results of interlocking nailing of distal tibial fractures].  

PubMed

Between 1982 and 1989, 117 fractures of the distal part of the lower leg were surgically treated in the Trauma Clinic belonging to the employers' liability insurance company in Frankfurt/Main. A follow-up examination of 85 of these patients, based on X-ray series, clinical reports, and insurance files, shows the functional results. Because of the high proportion of good to excellent results (95.4%), we consider fracture of the distal tibia a good indication for interlocking nailing, even from the aspect of the borderline indication of fracture in the fifth sixth. In open fractures of the distal part of the lower leg we consider the change of method from primary stabilization with external fixation to secondary interlocking nailing an appropriate procedure. The methods presented for internal fixation of fractures of the distal tibia by interlocking nailing allow early partial and full weight-bearing with the stability needed for exercising. PMID:2270498

Schnettler, R; Börner, M; Soldner, E

1990-11-01

5

Interference screw failure in distal biceps endobutton repair: case report.  

PubMed

Endobutton (Arthrex, Naples, FL) fixation of distal biceps rupture with interference screw fixation provides for a secure repair, allowing for early motion. We present a case in which Endobutton fixation failed with a loose interference screw, rendering the distal biceps attachment incompetent. Revision surgery with an extensile approach, mobilization of the biceps, and repeat Endobutton fixation at a more distal site provided a secure fixation with an excellent clinical outcome. An understanding of the mechanism of failure might allow surgeons to perform this procedure with a lower incidence of complications. PMID:20807629

Naidu, Sanjiv H

2010-09-01

6

[Molar distalization by using vertically installed mini-screws].  

PubMed

Mini-screws can be used for orthodontic anchorage in distalizing maxillary and mandibular molars. With them, practitioners can avoid the undesirable reciprocal movement that so often occurs when teeth are used as anchorage units. In this article, we propose a method of vertical insertion of mini-screws that places them in positions that will not interfere with movement of tooth roots. This allows orthodontists to use mass movements of groups of teeth or even of entire arches, thus reducing the need for extractions, simplifying treatment procedures, and enlarging the range of therapeutic possibilities. We evaluate the indications for this vertical placement in different anatomic situations. We suggest different sites for mini-screw placement and illustrate them with many clinical cases. PMID:23206370

Lee, Ju-Young

2012-12-01

7

Coracoclavicular screw fixation for unstable distal clavicle fractures.  

PubMed

Fifteen patients with Neer type II distal clavicle fracture were treated surgically. Operative treatment included open reduction and fixation of the proximal clavicular fragment to the coracoid process using a 6.5-mm cancellous screw and repair of the coracoclavicular ligaments. Fracture union occurred at a mean of 7 weeks postoperatively without any serious complications. All patients returned to the pre-injury level of activity with no residual pain or dysfunction. PMID:16119284

Macheras, George; Kateros, Konstantinos T; Savvidou, Olga D; Sofianos, John; Fawzy, Ernest A; Papagelopoulos, Panayiotis J

2005-07-01

8

Biomechanics of the interlocking nail  

Microsoft Academic Search

Conventional interlocking nails for the femur use an inclined proximal interlocking screw; the AO\\/ASIF universal interlocking nail utilizes a transverse interlocking screw which is anchored in cortical bone. The transverse position of the screw allows one to employ the nail for either the right or left side. The yield strength of the thinner diameter transverse screw, (thread 4.5 mm, core

C. Kinast; R. Frigg; S. M. Perren

1990-01-01

9

Fatigue strength of common tibial intramedullary nail distal locking screws  

Microsoft Academic Search

BACKGROUND: Premature failure of either the nail and\\/or locking screws with unstable fracture patterns may lead to angulation, shortening, malunion, and IM nail migration. Up to thirty percent of all unreamed nail locking screws can break after initial weight bearing is allowed at 8–10 weeks if union has not occurred. The primary problem this presents is hardware removal during revision

Lanny V. Griffin; Robert M Harris; Joseph J Zubak

2009-01-01

10

[Combination of intramedullary nail and covered screw osteosynthesis for managing distal tibial fracture with ankle joint involvement].  

PubMed

Fractures of the distal metaphysis of the tibia often include an extension into the ankle. Intramedullary nailing combined with covered screw osteosynthesis should reduce the high incidence of soft tissue and ankle problems and should be an alternative to open plate fixation, with good ultimate functional outcome. Between January 1993 and December 1995, a prospective study on 49 patients with distal metaphyseal tibia fracture and involvement of the ankle was performed. All the fractures were treated with intramedullary nailing combined with covered screw osteosynthesis, and plate fixation in cases of fibula fractures. There were 27 men and 22 women with an average age of 46.4 +/- 12.7 years (range 21-90). In most studies of the use of intramedullary nailing in distal tibial fractures the classification has been inadequate. Therefore a new classification according to Robinson et al. (1995) was used: 10 fractures were type II B (20.4%), 13 were type II C (26.5%), and 26 patients suffered a combination of type II B and type II C (53.1%). This fracture type was defined as type II D for use in this study. The severity of soft tissue injury was recorded using the Gustilo system in case of open (n = 19) and the Tscheme system in case of closed fractures (n = 30). In 31 patients distal tibia fracture was accompanied by a fracture of the fibula, which was first stabilized using a plate. For reconstruction of the distal articular surface, covered screw osteosynthesis was done. At the next step intramedullary nails were inserted and were statically locked proximally and distally. From January 1993 to February 1994, the reamed AO standard nail was used. After introduction of the unreamed tibial nail (UTN) all fractures were treated by this implant. Full load on the operated leg was allowed after 8 weeks. Union of the fracture was assessed by standard radiological and clinical criteria. Misalignment was defined as more than 5 degrees of angular rotation. Further surgery due to a valgus deformity in the ankle joint had to be done in three cases. There were no deep infections. Three patients had a superficial infection in the ankle area, but surgical debridement was not necessary. A leg shortening was found in 4 cases, but it was less than 1 cm in every case. Therefore, surgical correction was not done. Patients were reviewed at intervals of 2, 6, and 12 weeks, and after 6, and at least 12 months. All 49 patients were finally reviewed after an average time of 15.7 months (range 12-38). Bone fusion was reached 12.8 weeks (range 9-21) after the operative treatment. A specific assessment of the ankle symptoms was made using the score of Olerud and Molander (1984). In 29 patients excellent results were recorded. A satisfactory result was attained with 17 patients and just 3 patients were found to be unsatisfactory. Although proximity of distal tibia fracture to the ankle makes the treatment more complicated than for fractures of the tibial diaphysis, closed intramedullary nailing combined with covered screw fixation is a good alternative to open reduction and plate fixation. The major advantages are closed procedure and simplified interlocking techniques. Therefore, closed intramedullary nailing combined with covered screw fixation is a safe and effective method of managing this type of fracture. PMID:10025240

Rzesacz, E H; Könneker, W; Reilmann, H; Culemann, U

1998-12-01

11

The use of intraosseous screw for upper molar distalization: a case report.  

PubMed

The use of implants has made a major change in orthodontic treatment mechanics. They have replaced conventional unaesthetic and compliance dependent extraoral appliances with well accepted intraoral mechanics. Implants can be used in molar and canine distalization, intrusion and in extraoral force applications. In the present case report, treatment of a case using an intermaxillary fixation screw (IMF) will be presented. The treatment results will be evaluated using pretreatment, post distalization and post treatment cephalometric radiographs and dental casts. PMID:19212521

Polat-Ozsoy, Omür

2008-04-01

12

The Use of Intraosseous Screw for Upper Molar Distalization: A Case Report  

PubMed Central

The use of implants has made a major change in orthodontic treatment mechanics. They have replaced conventional unaesthetic and compliance dependent extraoral appliances with well accepted intraoral mechanics. Implants can be used in molar and canine distalization, intrusion and in extraoral force applications. In the present case report, treatment of a case using an intermaxillary fixation screw (IMF) will be presented. The treatment results will be evaluated using pretreatment, post distalization and post treatment cephalometric radiographs and dental casts.

Polat-Ozsoy, Omur

2008-01-01

13

Distal Tibial Metaphyseal Fractures: Does Blocking Screw Extend the Indication of Intramedullary Nailing?  

PubMed Central

Aim. To evaluate the clinical use of blocking screws as a supplement to stability in distal tibial metaphyseal fractures treated with statically locked intramedullary nail. Main Outcome Measurement. Alignment and reduction preoperatively, postoperatively, and at healing were the main outcome measured with an emphasis on maintenance of initial reduction on followup. Patients and Methods. This was a prospective study of 20 consecutive cases of distal tibial metaphyseal fractures treated with statically locked intramedullary nailing with supplementary blocking screw between August 2006 and September 2007 with a maximum followup of 3 years. Medullary canal diameter was measured at the levels of fracture and isthmus. Results. The mean diameter of tibia at the level of isthmus was 11.9?mm and at the fracture site was 22.9?mm. Mean length of distal fracture segment was 4.6?cm. Mean varus/valgus alignment was 10.3?degrees preoperatively and 1.7?degrees immediatly postoperatively and was maintained till union. Using Karlstrom-Olerud score the outcome was excellent to good in 90%. Conclusion. We conclude that the use of blocking screw as a supplement will aid in achieving and maintaining the reduction of distal tibial metaphyseal fractures when treated with intramedullary nailing thereby extending the indication of intramedullary nailing.

Moongilpatti Sengodan, Mugundhan; Vaidyanathan, Singaravadivelu; Karunanandaganapathy, Sankaralingam; Subbiah Subramanian, Sukumaran; Rajamani, Samuel Gnanam

2014-01-01

14

Distal tibial physeal bridge: a complication from a tension band plate and screw construct. Report of a case.  

PubMed

We report on a case of a tension band plate and screw construct (Eight Plate) used over the anterior distal tibia in an 9-year-old girl in an attempt to induce recurvatum of the ankle joint to correct a recalcitrant equinus deformity. With growth of the distal tibial physis, the epiphyseal screw was drawn through the physis into the distal tibial metaphysis, resulting in the creation of a transphyseal bony bar. Caution should be exercised when attempting temporary hemiepiphyseodesis using a plate and screw construct in small epiphyses or in an osteopenic bone. PMID:22158054

Oda, Jon E; Thacker, Mihir M

2013-05-01

15

Osteosynthesis of distal radial fractures with a volar locking screw plate system  

Microsoft Academic Search

We developed a locking screw plate system for the stabilisation of distal radial fractures, which can be inserted through a standard volar approach and in which the locking mechanism allows early post-operative mobilisation. Forty-nine patients with 50 fractures underwent surgical treatment; 66% were type C fractures. The mean follow-up was 26 months. According to the scores of Gartland and Werley

H. Drobetz; E. Kutscha-Lissberg

2003-01-01

16

Radiographic Evaluation of Dorsal Screw Penetration After Volar Fixed-Angle Plating of the Distal Radius: A Cadaveric Study  

Microsoft Academic Search

Introduction  Extensor tendon irritation and attritional tendon ruptures are potentially serious complications after open reduction and\\u000a internal fixation of distal radius fractures. These complications are well recognized after dorsal plating of distal radii;\\u000a and these are now being reported after errant screw placement during volar fixed-angle plating. Intraoperative detection of\\u000a improper screw placement is critical, as corrective action can be taken

Steven D. Maschke; Peter J. Evans; David Schub; Richard Drake; Jeffrey N. Lawton

2007-01-01

17

Radiographic Evaluation of Dorsal Screw Penetration After Volar Fixed-Angle Plating of the Distal Radius: A Cadaveric Study  

PubMed Central

Introduction Extensor tendon irritation and attritional tendon ruptures are potentially serious complications after open reduction and internal fixation of distal radius fractures. These complications are well recognized after dorsal plating of distal radii; and these are now being reported after errant screw placement during volar fixed-angle plating. Intraoperative detection of improper screw placement is critical, as corrective action can be taken before completion of the operative procedure. The purpose of this study was to define the extensor tendon compartments at risk secondary to dorsal screw penetration and to compare pronation and supination fluoroscopic images with standard lateral images in demonstrating dorsal screw prominence during volar locked plating. Methods Eight fresh-frozen human cadaveric upper extremities underwent fixation with a volar, fixed-angle distal radius locked plate (Wright Medical Technology, Arlington, TN). Three fluoroscopic views (lateral, supinated, and pronated) followed by dorsal wrist dissections were compared to determine accuracy in detecting dorsal screw prominence and extensor tendon compartment violation. Subsequently, screws measuring 2, 4, 6, 8, and 10(mm longer than the measured depths were sequentially inserted into each distal locking screw, with each image deemed either "in" (completely inside the bone) or "out" (prominent screw tip dorsally-would typically be exchanged for a shorter screw intraoperatively). Results The radial most distal locking screw (position 1) violated either the first (25%) or second (75%) extensor tendon compartments. The average screw prominence required for radiographic detection was: 6.5(mm for lateral views and 2(mm for supinated views. Pronated views did not identify prominent screws. Screws occupying plate position 2 consistently entered Lister's tubercle, with 5/8 exiting the apex and 3/8 exiting the radial base. The average screw prominences for radiographic detection were: 2.75(mm-lateral views and 3.0(mm-supinated views. Although the screws entered the second dorsal compartment, they did not encroach upon either of the tendons. Screws occupying plate position 3 violated the third extensor tendon compartment in 7/8 specimens with 1/8 exiting the Ulan base of Lister's tubercle. The average screw prominences for radiographic detection were: 3.5(mm-lateral views and 2.5(mm-pronated views. Supinated views did not identify prominent hardware. Screws occupying plate position 4 all violated the IV dorsal extensor compartment-2/8 screws were noted to tent the posterior interosseous nerve. The average screw prominences required for radiographic detection were: 4.0(mm-lateral views and 2.5(mm-pronated views. The supinated views did not identify prominent screws. Conclusions Volar fixed-angle plating has shown great promise in the advancement of distal radius fracture management. We have seen in our referral practices and in the literature an increase in the number of extensor tendon complications arising from unrecognized dorsally prominent screws, pegs, or tines. Standard PA and lateral radiographs cannot adequately visualize screw position and length secondary to the complex geometry of the dorsal cortex. We believe this study supports the routine application of intraoperative, oblique pronosupination fluoroscopic imaging for enhanced confirmation of distal locking screw position and length.

Maschke, Steven D.; Evans, Peter J.; Schub, David; Drake, Richard

2007-01-01

18

The wire interlock technique for harvesting a partial-width distally attached tendon graft.  

PubMed

A wire interlock technique useful for harvesting a partial-width tendon graft with an intact insertion for local reconstructive procedures is described. This technique is rapid and reliable for procuring attached tendon grafts with minimal exposure. The technique was used to harvest a flexor carpi radialis tendon graft for basal joint interposition arthroplasty in 12 patients. This method also may be readily applicable for other procedures requiring local ligament reconstruction with a partial-width tendon graft. (J Hand Surg 2000; 25A:176-182. PMID:10642490

Lester, B; McCormack, R R; Jeong, G K

2000-01-01

19

A simple mini-screw assembly for simultaneous molar uprighting and distalization--a case of adjunctive adult orthodontics.  

PubMed

Anchorage is a major concern in adult mutilated dentition. However, with the explosive development of Temporary Anchorage Devices (TADs) newer avenues in orthodontic treatment philosophy have opened up. Mini-screws are found to be stable during such treatments, demonstrating that they could provide absolute anchorage for tooth movement. The present article describes a simple, yet effective technique for simultaneous molar uprighting and distalization, using direct skeletal anchorage using a mini-screw supported assembly in a 38 years old male patient as part of adjunctive adult orthodontics with mutilated dentition. PMID:23729134

Reddy, Vijay; Parmar, Renu; Jamadar, Irfan Abdul Razak; Reddy, Rajesh; Reddy, Deepti

2013-01-01

20

A Robust and Accurate Two-Stage Approach for Automatic Recovery of Distal Locking Holes in Computer-Assisted IntramedullaryNailing of Femoral Shaft Fractures  

Microsoft Academic Search

It has been recognized that one of the most difficult steps in intramedullary nailing of femoral shaft fractures is the distal locking- the insertion of distal transverse interlocking screws, for which it is necessary to know the positions and orientations of the distal locking holes (DLHs) of the intramedullary nail (IMN). This paper presents a robust and accurate approach for

Guoyan Zheng; Xuan Zhang; Daniel Haschtmann; Philippe Gedet; Xiao Dong; Lutz-peter Nolte

2008-01-01

21

Retrograde intramedullary nails with distal screws locked to the nail have higher fatigue strength than locking plates in the treatment of supracondylar femoral fractures: A cadaver-based laboratory investigation.  

PubMed

We investigated a new intramedullary locking nail that allows the distal interlocking screws to be locked to the nail. We compared fixation using this new implant with fixation using either a conventional nail or a locking plate in a laboratory simulation of an osteoporotic fracture of the distal femur. A total of 15 human cadaver femora were used to simulate an AO 33-A3 fracture pattern. Paired specimens compared fixation using either a locking or non-locking retrograde nail, and using either a locking retrograde nail or a locking plate. The constructs underwent cyclical loading to simulate single-leg stance up to 125,000 cycles. Axial and torsional stiffness and displacement, cycles to failure and modes of failure were recorded for each specimen. When compared with locking plate constructs, locking nail constructs had significantly longer mean fatigue life (75,800 cycles (SD 33,900) vs 12,800 cycles (SD 6100); p = 0.007) and mean axial stiffness (220 N/mm (SD 80) vs 70 N/mm (SD 18); p = 0.005), but lower mean torsional stiffness (2.5 Nm/° (SD 0.9) vs 5.1 Nm/° (SD 1.5); p = 0.008). In addition, in the nail group the mode of failure was either cut-out of the distal screws or breakage of nails, and in the locking plate group breakage of the plate was always the mode of failure. Locking nail constructs had significantly longer mean fatigue life than non-locking nail constructs (78,900 cycles (SD 25,600) vs 52,400 cycles (SD 22,500); p = 0.04). The new locking retrograde femoral nail showed better stiffness and fatigue life than locking plates, and superior fatigue life to non-locking nails, which may be advantageous in elderly patients. PMID:24395321

Pekmezci, M; McDonald, E; Buckley, J; Kandemir, U

2014-01-01

22

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

23

A prospective, randomised trial comparing the use of absorbable and metallic screws in the fixation of distal tibiofibular syndesmosis injuries: mid-term follow-up.  

PubMed

Our aim was to compare polylevolactic acid screws with titanium screws when used for fixation of the distal tibiofibular syndesmosis at mid-term follow-up. A total of 168 patients, with a mean age of 38.5 years (18 to 72) who were randomly allocated to receive either polylevolactic acid (n = 86) or metallic (n = 82) screws were included. The Baird scoring system was used to assess the overall satisfaction and functional recovery post-operatively. The demographic details and characteristics of the injury were similar in the two groups. The mean follow-up was 55.8 months (48 to 66). The Baird scores were similar in the two groups at the final follow-up. Patients in the polylevolactic acid group had a greater mean dorsiflexion (p = 0.011) and plantar-flexion of the injured ankles (p < 0.001). In the same group, 18 patients had a mild and eight patients had a moderate foreign body reaction. In the metallic groups eight had mild and none had a moderate foreign body reaction (p < 0.001). In total, three patients in the polylevolactic acid group and none in the metallic group had heterotopic ossification (p = 0.246). We conclude that both screws provide adequate fixation and functional recovery, but polylevolactic acid screws are associated with a higher incidence of foreign body reactions. PMID:24692626

Sun, H; Luo, C F; Zhong, B; Shi, H P; Zhang, C Q; Zeng, B F

2014-04-01

24

Use of the radial groove view intra-operatively to prevent damage to the extensor pollicis longus tendon by protruding screws during volar plating of a distal radial fracture.  

PubMed

The aims of this study were to assess the efficacy of a newly designed radiological technique (the radial groove view) for the detection of protrusion of screws in the groove for the extensor pollicis longus tendon (EPL) during plating of distal radial fractures. We also aimed to determine the optimum position of the forearm to obtain this view. We initially analysed the anatomy of the EPL groove by performing three-dimensional CT on 51 normal forearms. The mean horizontal angle of the groove was 17.8° (14° to 23°). We found that the ideal position of the fluoroscopic beam to obtain this view was 20° in the horizontal plane and 5° in the sagittal plane. We then intra-operatively assessed the use of the radial groove view for detecting protrusion of screws in the EPL groove in 93 fractures that were treated by volar plating. A total of 13 protruding screws were detected. They were changed to shorter screws and these patients underwent CT scans of the wrist immediately post-operatively. There remained one screw that was protruding. These findings suggest that the use of the radial groove view intra-operatively is a good method of assessing the possible protrusion of screws into the groove of EPL when plating a fracture of the distal radius. PMID:24078534

Lee, S K; Bae, K W; Choy, W S

2013-10-01

25

Radiation exposure to the surgeon during closed interlocking intramedullary nailing  

Microsoft Academic Search

During interlocking intramedullary nailing of twenty-five femoral and five tibial fractures, the primary surgeon wore both a universal film badge on the collar of the lead apron and a thermoluminescent dosimeter ring on the dominant hand to quantify the radiation that he or she received. When distal interlocking was performed, the first ring was removed and a second ring was

PAUL E. LEVIN; ROBERT W. SCHOEN; BRUCE D. BROWNER

1987-01-01

26

Lithium Lens Interlocks  

Microsoft Academic Search

The lithium lens in the antiproton source target vault is protected by an interlock system, which is located in relay racks R5 and R6 near the southwest corner of the Target Hall (building APO). The interlock system consists of crates of commercial signal conditioner and alarm modules built by Acromag, Inc and interlock Master Modules built by Fermilab: Twenty analog

J. Krider

1985-01-01

27

[Interlocking nailing of the humerus].  

PubMed

Within a 3-year period a total of 42 humeral fractures were treated. Nineteen of these were operated on with the Seidel intramullary interlocking nail. Most of the fractures could be classified into group A (AO classification); three type B and four type C fractures occurred. Two patients had pathological fractures due to bone metastases. Mean hospital inpatient treatment was 24 days. Besides two infections seven system-specific complications occurred. A discrepancy between the diameter of the nail and the width of medullary cavity was the reason in one case for an additional fracture and in another case for nonunion because of loosening of the nail tip in the distal fragment. Three further intraoperative fractures occurred during impaction of the nail, the reasons are also device-specific and are carefully analyzed. In two cases we were forced to remove the nail because of subacromial impingement due to an overranging proximal nail end. Finally, a normal intraoperative and postoperative course with good functional results could only be observed in approximately half the cases. Thus, our initial optimism with respect to the outstanding theoretical concept was dampened, so that the interlocking humerus nail is now just applied in pathological shaft fractures. PMID:8342061

Ruf, W; Pauly, E

1993-06-01

28

Interlocking properties of buckyballs  

NASA Astrophysics Data System (ADS)

A geometric possibility of arranging C 60 molecules (buckyballs) in a monolayer in which they are interlocked topologically is considered. Three arrangements of this type, all different from the common, face centred cubic fullerene structure, are presented. Although in this analysis the buckyballs are treated in a simplified way, as rigid bodies, the realization of structures in which C 60 molecules would be arranged in the way described may lead to mechanically stronger fullerene monolayers. The Letter aims to initiate discussion of the viability and the potential of the new systems of interlocked buckyballs.

Dyskin, A. V.; Estrin, Y.; Kanel-Belov, A. J.; Pasternak, E.

2003-12-01

29

Open interlocked nailing without a targeting device or X-ray guidance for non-union of the femur: a case series.  

PubMed

From October 2005 to August 2007, we operated on six patients who had femoral non-unions and performed interlocked intramedullary nailing without X-ray guidance or a targeting device. There were three fractures of the distal femur, two fractures of the mid-shaft and one of the proximal femur. Fatigue failure of a non-interlocked Kuntscher nail and one nail migration were the presenting features in two patients. The presence of sclerosis of the bone ends in four cases and a need for cancellous bone grafts at the site of non-union in all patients made wide dissection and open reduction unavoidable. There was a limb length discrepancy in all patients before surgical intervention. Partial weight bearing was commenced at 6 weeks post-operation. There was no case of wound infection. There was no misplaced screw. Minimum range of knee flexion was 105° at 2 months post-operation. These early results call for a closer look at this cheap, safe and effective means of handling femoral non-union in third world societies where there is paucity of instrumentation and implants for interlocked nailing. PMID:21286356

Ogbemudia, Alfred O; Bafor, Anire; Igbinovia, Efosa; Ogbemudia, Peter E

2010-12-01

30

Interlocking properties of buckyballs  

Microsoft Academic Search

A geometric possibility of arranging C60 molecules (buckyballs) in a monolayer in which they are interlocked topologically is considered. Three arrangements of this type, all different from the common, face centred cubic fullerene structure, are presented. Although in this analysis the buckyballs are treated in a simplified way, as rigid bodies, the realization of structures in which C60 molecules would

A. V. Dyskin; Y. Estrin; A. J. Kanel-Belov; E. Pasternak

2003-01-01

31

Specifying Railway Interlocking Systems  

Microsoft Academic Search

One of the Grand Challenges in Computer Science is to verify railway interlocking systems (1). We give a generic datatype of control tables and ladder logic (2,3), and extract from these verification conditions (4). A proof o f the cor- rectness of these conditions is performed using induction and a datatype of reachable states (5). Finally, some concluding remarks are

Karim Kanso; Anton Setzer

32

Split spline screw  

NASA Technical Reports Server (NTRS)

A split spline screw type payload fastener assembly, including three identical male and female type split spline sections, is discussed. The male spline sections are formed on the head of a male type spline driver. Each of the split male type spline sections has an outwardly projecting load baring segment including a convex upper surface which is adapted to engage a complementary concave surface of a female spline receptor in the form of a hollow bolt head. Additionally, the male spline section also includes a horizontal spline releasing segment and a spline tightening segment below each load bearing segment. The spline tightening segment consists of a vertical web of constant thickness. The web has at least one flat vertical wall surface which is designed to contact a generally flat vertically extending wall surface tab of the bolt head. Mutual interlocking and unlocking of the male and female splines results upon clockwise and counter clockwise turning of the driver element.

Vranish, John M. (inventor)

1993-01-01

33

Lithium Lens Interlocks  

SciTech Connect

The lithium lens in the antiproton source target vault is protected by an interlock system, which is located in relay racks R5 and R6 near the southwest corner of the Target Hall (building APO). The interlock system consists of crates of commercial signal conditioner and alarm modules built by Acromag, Inc and interlock Master Modules built by Fermilab: Twenty analog signals from the lens/transformer, power supply, and cooling water system are buffered with signal conditioners (amplifiers), which are located in creates R5C and R5E. The signals and conditioner assignments are listed in Table 1. Interconnection details are shown in Figure 1. Thermocouple signals come into the conditioners directly from the vault or water system via 12-pair multiconductor thermocouple extension cables. All other signals pass through a master connection panel on the east end of rack R6. Water flow signals are AC voltages which must be converted by electronics in crate D2B to DC voltages before entering their signal conditioners. Each conditioner drives two parallel outputs. One output goes to a Multiplexed Analog to Digital Converter (MADC 25), which is located in R5D. This voltage output is read by the accelerator control network (ACNET) and can be displayed at any control console on parameter page P46. The other voltage output is connected to an alarm module. Thirteen analog signals are processed by alarm modules, which are located in crates R6B and R6C. Alarm connection details are shown in Figure 2. Each alarm module contains two DPDT relays, one for an upper limit and one for a lower limit. The relays are latching, so that once an input has passed outside a limit, that limit relay remains in the tripped condition until an operator issues a reset pulse. The reset may be generated locally with a pushbutton on the appropriate interlock master module or remotely from controls parameter page P46 via ACNET. Alarm settings are summarized in engineering units in Table 1, and actual comparitor voltage settings are listed in Figure 2. Each alarm crate contains 10 module slots and is wired as shown in Figure 3, except for the water conductivity slot, which is wired to a separate interlock chain output. Normally open contacts are used for interlock chains, while normally closed contacts provide status bits. The interlock chain outputs are connected to Interlock Master Modules located in D5C. Status bits are read into ACNET through a multiplexer in R4A, and can be displayed on parameter page S40. Any alarm slot may be bypassed by inserting a 'dummy' printed circuit card in place of a module. Each interlock master module sums 5 inputs and provides 3 reed relay contact closure outputs. A circuit schematic is shown in Figure 4. Input 1 requires +5 volts, and directly energizes an interlock chain relay. Input 2 and 3 require TTL logic levels, and inputs 4 and 5 require and external contact closure. Internal switches select which inputs are active Interlock master interconnections are shown in Figure 5. The lens uses two masters, one for water conductivity and the other for all interlocked conditions. The Conductivity Master controls the lens water purging system and also energizes one input of the General Master. The General Master provides the external interlock for the pulsed power supply. If lithium comes into contact with the cooling water, the conductivity master will trip. Output 2 of the Master shuts off the water circulating pump and initiates purging hardware, which isolates the lens from the water supply and allows inert gas to force remaining water from the lens into a reservoir located in the vault. Output 1 of the Master, which is connected to input 4 of the lens General Master, causes the General Master to trip and disable the pulsed power supply. All other lens alarm conditions (except conductivity) enter input 1 and 2 of the Lens General Master. An alarm condition from these inputs will disable the pulsed power supply, but the water system will remain on. Each interlock master has a manual Emergency Stop pushbutton (red) on its front pan

Krider, J.

1985-12-18

34

Model Checking Railway Interlocking Systems  

Microsoft Academic Search

For supporting the analysis of railway interlocking systems in the early stage of their design we propose the use of model checking. We investigate the use of the formal modelling language CSP and the corresponding model checker FDR. In this paper, we describe the basics of this formalism and introduce our formal model of a railway interlocking system. Checking this

Kirsten Winter

2002-01-01

35

Option Backdating and Board Interlocks  

Microsoft Academic Search

We examine the role of board connections in explaining how the controversial practice of backdating employee stock options spread to a large number of firms across a wide range of industries. The increase in the likelihood that a firm begins to backdate stock options that can be explained by having a board member who is interlocked to a previously identified

John Bizjak; Michael Lemmon; Ryan Whitby

2009-01-01

36

Interlocking Directorates and Business Groups: Belgian Evidence  

Microsoft Academic Search

We investigate the determinants of interlocking directorates and their impact on company performance for a Belgian sample of 286 companies affiliated with a business group and 2,136 stand-alone companies. Most of these companies are not listed. We find that companies belonging to a group have much more interlocking directorates than stand-alone companies. Group companies tend to be strongly interlocked with

An ROMMENS; Cuyvers L; Deloof M

2007-01-01

37

2. ENVIRONMENT, FROM SOUTHEAST, SHOWING B&P INTERLOCKING TOWER, AUXILIARY INTERLOCKING ...  

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

2. ENVIRONMENT, FROM SOUTHEAST, SHOWING B&P INTERLOCKING TOWER, AUXILIARY INTERLOCKING BUILDING, AND POWER SUBSTATION - Baltimore & Potomac Interlocking Tower, Adjacent to AMTRAK railroad tracks in block bounded by Howard Street, Jones Falls Expressway, Maryland Avenue & Falls Road, Baltimore, Independent City, MD

38

Biomechanics of femoral interlocking nails.  

PubMed

Today there is a variety of different interlocking intramedullary nail designs available for the femur. We compared different nail types in the bone implant complex (BIC) of four unreamed solid nails and a slotted reamed nail with simulated comminuted mid shaft fractures to see if there are major differences in stiffness for axial load, bending and torsion. The fractures were simulated by a 2 cm defect osteotomy in paired human cadaver femora. Each bone was tested intact in a universal testing machine, osteotomy and osteosynthesis were performed, and the BIC was tested. Relative stiffness was calculated. In torque testing the unslotted solid nail showed significantly more stiffness (0.6-1.8 Nm/degrees) compared to the slotted nail (0.2 Nm/degrees). Compared to intact bone (6.9 Nm/degrees), both groups of nails were significantly less stiff (relative stiffness 2-20%). In axial load and bending testing the large diameter unreamed nail showed significantly higher stiffness (32-68%). This study shows that stiffness of bone implant complex in interlocking femoral nails is more dependent on nail profile than on the pressfit of nails in the medullary canal. PMID:10831743

Schandelmaier, P; Farouk, O; Krettek, C; Reimers, N; Mannss, J; Tscherne, H

2000-07-01

39

Cartelizing effects of horizontal shareholding interlocks  

Microsoft Academic Search

Some models of industries with horizontal shareholding interlocks are generalized. First, we consider industries where firms exhibit different technologies and more general market demand functions. The cartelizing effects of financial interlocks are examined using both the Lerner index and the Herfindahl-Hirshman index. Furthermore, the model is extended to consider multiproduct oligopolies. We find a compact expression for the Lerner index

Ugo Merlone

2001-01-01

40

Screw-locking wrench  

NASA Technical Reports Server (NTRS)

A tool comprises a first handle and a second handle, each handle extending from a gripping end portion to a working end portion, the first handle having first screw threads disposed circumferentially about an inner portion of a first through-hole at the working end portion thereof, the second handle having second screw threads disposed circumferentially about an inner portion of a second through-hole at the working end portion thereof, the first and second respective through-holes being disposed concentrically about a common axis of the working end portions. First and second screw locks preferably are disposed concentrically with the first and second respective through-holes, the first screw lock having a plurality of locking/unlocking screw threads for engaging the first screw threads of the first handle, the second screw lock having a plurality of locking/unlocking screw threads for engaging the second screw threads of the second handle. A locking clutch drive, disposed concentrically with the first and second respective through-holes, engages the first screw lock and the second screw lock. The first handle and the second handle are selectively operable at their gripping end portions by a user using a single hand to activate the first and second screw locks to lock the locking clutch drive for either clockwise rotation about the common axis, or counter-clockwise rotation about the common axis, or to release the locking clutch drive so that the handles can be rotated together about the common axis either the clockwise or counter-clockwise direction without rotation of the locking clutch drive.

Vranish, John M. (Inventor)

2007-01-01

41

Arthroscopically assisted reconstruction and percutaneous screw fixation of a Pilon tibial fracture.  

PubMed

We report a case of closed distal tibial fracture (AO 43C3), treated successfully with arthroscopically assisted minimally invasive reduction and percutaneous screw fixation. Techniques and postoperative treatment are described. PMID:12724669

Kralinger, Franz; Lutz, Martin; Wambacher, Markus; Smekal, Vinzenz; Golser, Karl

2003-01-01

42

[Reamed interlocking intramedullary nail in the treatment of tibial and fibular fractures].  

PubMed

To analyse retrospectively the results of thirty-eight fractures of the tibial and fibular treated with reamedintramedullary interlocking nail from May 1997 to June 2000. The patients were followed for an average of 14.6(range: 6-32) months. The mean age was 32.8(range: 18-64) years, the sex distribution was 29 males and 9 females. 26 fractures were closed (One case was failure of plate and screws) and 12 were opened: 6 were graded I, 4 were II, 2 IIIa, according to Gustilo's classification. A solid union was achieved in all patients within a period of 6 months. There were no deep infections except one case of superficial infection. Cases of deformity or peroneal nerve injury were no noticed. It is believed that reamed intramedullary interlocking nail allows a stable and safety fixation in open or closed tibial and fibular fractures. PMID:12536751

Zhang, D H; Yang, H F; Zhan, R S

2001-08-28

43

Coastal protection using topological interlocking blocks  

NASA Astrophysics Data System (ADS)

The coastal protection systems mainly rely on the self-weight of armour blocks to ensure its stability. We propose a system of interlocking armour blocks, which form plate-shape assemblies. The shape and the position of the blocks are chosen in such a way as to impose kinematic constraints that prevent the blocks from being removed from the assembly. The topological interlocking shapes include simple convex blocks such as platonic solids, the most practical being tetrahedra, cubes and octahedra. Another class of topological interlocking blocks is so-called osteomorphic blocks, which form plate-like assemblies tolerant to random block removal (almost 25% of blocks need to be removed for the assembly to loose integrity). Both classes require peripheral constraint, which can be provided either by the weight of the blocks or post-tensioned internal cables. The interlocking assemblies provide increased stability because lifting one block involves lifting (and bending) the whole assembly. We model the effect of interlocking by introducing an equivalent additional self-weight of the armour blocks. This additional self-weight is proportional to the critical pressure needed to cause bending of the interlocking assembly when it loses stability. Using beam approximation we find an equivalent stability coefficient for interlocking. It is found to be greater than the stability coefficient of a structure with similar blocks without interlocking. In the case when the peripheral constraint is provided by the weight of the blocks and for the slope angle of 45o, the effective stability coefficient for a structure of 100 blocks is 33% higher than the one for a similar structure without interlocking. Further increase in the stability coefficient can be reached by a specially constructed peripheral constraint system, for instance by using post-tension cables.

Pasternak, Elena; Dyskin, Arcady; Pattiaratchi, Charitha; Pelinovsky, Efim

2013-04-01

44

Plates, pins, and interlocking nails.  

PubMed

Evidence-based criteria that promise the best treatment outcome for bovine fracture patients have not been established. Internal fixation with plates and screws allows successful management of many long bone fractures in calves as well as in heavier cattle. Intramedullary pins may be better or equally suited for repair of humerus or femoral fractures in calves, respectively. In richly comminuted fractures in heavy cattle, methods of external fixation are still indicated. With newly introduced locking plates, treatment options for repair of long bone fractures in cattle have further improved, but high costs and a guarded prognosis limit their application. PMID:24534661

Nuss, Karl

2014-03-01

45

49 CFR 236.772 - Machine, interlocking.  

Code of Federal Regulations, 2013 CFR

...Definitions § 236.772 Machine, interlocking. An assemblage of manually operated levers or other devices for the control of signals, switches or other units. Cross Reference: Magnet, track, see §...

2013-10-01

46

49 CFR 236.751 - Interlocking, manual.  

Code of Federal Regulations, 2013 CFR

...manual. An arrangement of signals and signal appliances operated from an interlocking machine and so interconnected by means of mechanical and/or electric locking that their movements must succeed each other in proper sequence, train...

2013-10-01

47

Distal cholangiocarcinoma.  

PubMed

Cholangiocarcinoma involving the distal common bile duct (distal cholangiocarcinoma [DCC]) is a periampullary neoplasm that is less common than, but often difficult to distinguish from, pancreatic adenocarcinoma (PDA). The prognosis and cure rate of DCC is improved over that of PDA, but it remains a highly lethal disease. Although the diagnostic and therapeutic management of DCC is not dissimilar from PDA, the pathophysiology is, in many instances, distinctly different. A multi-disciplinary approach toward DCC is important. PMID:24679424

Dickson, Paxton V; Behrman, Stephen W

2014-04-01

48

Palmar locking plate for treatment of unstable dorsal dislocated distal radius fractures  

Microsoft Academic Search

Introduction This study investigates the clinical and radiological results of open reduction and internal fixation of unstable distal radial fractures using a palmar placed interlocking plate system with no substitutes for treatment of the dorsal metaphyseal fracture void. Materials and methods Nineteen patients with a mean age of 61 years (range 49-78 years) and a dorsally dis- placed distal radial

R. Arora; M. Lutz; D. Fritz; R. Zimmermann; J. Oberladstätter; M. Gabl

2005-01-01

49

Maxillary molar distalization with a bone-anchored pendulum appliance.  

PubMed

To obtain an effective and compliance-free molar distalization without an anchorage loss, we designed the bone-anchored pendulum appliance (BAPA). The aim of this study was to evaluate the stability of the anchoring screw, distalization of the maxillary molars, and the movement of teeth anterior to maxillary first molars. The study group comprised 10 patients (mean age 13.5 +/- 1.8 years) with Class II molar relationship. A conventional pendulum appliance was modified to obtain anchorage from an intraosseous screw instead of the premolars. The screw was placed in the anterior paramedian region of the median palatal suture. Skeletal and dental changes were measured on cephalograms, and dental casts were obtained before and after distalization. A super Class I molar relationship was achieved in a mean period of 7.0 +/- 1.8 months. The maxillary first molars distalized an average of 6.4 +/- 1.3 mm in the region of the dental crown by tipping distally an average of 10.9 degrees +/- 2.8 degrees . Also, the maxillary second premolar and first premolar moved distally an average of 5.4 +/- 1.3 mm and 3.8 +/- 1.1 mm, respectively. The premolars tipped significantly distally. No anterior incisor movement was detected. The BAPA was found to be an effective, minimally invasive, and compliance-free intraoral distalization appliance for achieving both molar and premolar distalization without any anchorage loss. PMID:16808573

Kircelli, Beyza Hancio?lu; Pekta?, Zafer Ozgür; Kircelli, Cem

2006-07-01

50

'Screw'--appendicitis.  

PubMed

We report a rare case of appendicitis due to screw in the appendix in a 4-year old boy. An appendicectomy was done. Foreign body appendicitis should be treated with early surgical intervention. PMID:17827638

Samujh, Ram; Mansoor, Khizer; Khan, Imran; Mannan, A

2007-08-01

51

Survey of Screw Feeders.  

National Technical Information Service (NTIS)

This report presents the results of a survey to determine the availability of screw feeders for use in areas related to coal feeding in the field of coal conversion. 15 references. (ERA citation 09:037045)

G. Sine

1983-01-01

52

Helical screw viscometer  

DOEpatents

A helical screw viscometer for the measurement of the viscosity of Newtonian and non-Newtonian fluids comprising an elongated cylindrical container closed by end caps defining a circular cylindrical cavity within the container, a cylindrical rotor member having a helical screw or ribbon flight carried by the outer periphery thereof rotatably carried within the cavity whereby the fluid to be measured is confined in the cavity filling the space between the rotor and the container wall. The rotor member is supported by axle members journaled in the end caps, one axle extending through one end cap and connectable to a drive source. A pair of longitudinally spaced ports are provided through the wall of the container in communication with the cavity and a differential pressure meter is connected between the ports for measuring the pressure drop caused by the rotation of the helical screw rotor acting on the confined fluid for computing viscosity.

Aubert, J.H.; Chapman, R.N.; Kraynik, A.M.

1983-06-30

53

Fabrication and Evaluation of a Noncompliant Molar Distalizing Appliance: Bonded Molar Distalizer  

PubMed Central

Objective Attempts to treat class II malocclusions without extraction in non-compliant patients have led to utilization of intraoral molar distalizing appliances. The purpose of this study was to investigate dental and skeletal effects of Bonded Molar Distalizer (BMD) which is a simple molar distalizing appliance. Materials and Methods Sixteen patients (12 girls, four boys) with bilateral half-cusp class II molar relationship, erupted permanent second molars and normal or vertical growth pattern were selected for bilateral distalization of maxillary molars via BMD. The screws were activated every other day, alternately. Lateral cephalograms and study models were obtained before treatment and after 11 weeks activation of the appliance. Results Significant amounts of molar distalization, molar distal tipping and anchorage loss were observed. The mean maxillary first molar distal movement was 1.22±0.936 mm with a distal tipping of 2.97±3.74 degrees in 11 weeks. The rate of distal movement was 0.48 mm per month. Reciprocal mesial movement of the first premolars was 2.26±1.12 mm with a mesial tipping of 4.25±3.12 degrees. Maxillary incisors moved 3.55±1.46 mm and tipped 9.87±5.03 degrees mesially. Lower anterior face height (LAFH) decreased 1.28±1.36 mm. Conclusion BMD is appropriate for distalizing maxillary molars, especially in patients with critical LAFH, although significant amounts of anchorage loss occur using this appliance.

Sodagar, A.; Ahmad Akhoundi, M. S.; Rafighii, A.; Arab, S.

2011-01-01

54

Blocks and Screws  

NSDL National Science Digital Library

In this lesson, each student is given a block of wood and a screw (or nail), and is asked to put the screw into the block, without any tool (like a screwdriver or hammer). Their efforts, with varying success, lead to a discussion of contrivances, using various items and strategies as make-do (contrived) tools for which they were not intended, and an exploration of many examples of contrivances or adaptive compromises and other imperfections in the living world, especially in humans. This situation may be better explained by evolution rather than the result of intelligent design.

Patterson, Tim

55

Predicting repeat DUI offenses with the alcohol interlock recorder  

Microsoft Academic Search

The aim of this report has been to use information contained in the alcohol ignition interlock recorder to determine whether systematic analysis of it can be used to predict which DUI offenders will recidivate during the first 2 years after the interlock is removed. The interlock record was accumulated during a 4-year intervention study in Alberta, Canada. Data from more

Paul R Marques; A. Scott Tippetts; Robert B Voas; Douglas J Beirness

2001-01-01

56

Automated Verification of Signalling Principles in Railway Interlockings  

Microsoft Academic Search

In this paper we present a verification strategy for signalling principles for the control of a railway interlock- ing system written in ladder logic. All translation steps have been implemented and tested on a real-world example of a railway interlocking system. The steps in this translation are as follows: 1. The development of a mathematical model of a railway interlocking

Karim Kanso; Faron Moller; Anton Setzer

2008-01-01

57

Automated Verification of Signalling Principles in Railway Interlocking Systems  

Microsoft Academic Search

In this paper we present a verification strategy for signalling principles for the control of a railway interlocking system written in ladder logic. All translation steps have been implemented and tested on a real-world example of a railway interlocking system. The steps in this translation are as follows: 1. The development of a mathematical model of a railway interlocking system

Karim Kanso; Faron Moller; Anton Setzer

2009-01-01

58

Innovation: the induction heated screw.  

National Technical Information Service (NTIS)

The Research and Development Division at EDF has developed an original technique for heating, drying or baking powder products: the induction heated Archimedes screw. Its main characteristic is simultaneous heating of the screw and the sleeve. (author). 4...

B. Paya

1993-01-01

59

Interlocking Egg-Crate Type Grid Assembly.  

National Technical Information Service (NTIS)

Disclosed is an interlocking egg-crate hexagonal grid for supporting a nuclear fuel pin in a hexagonal array. The grid is formed from strips bent at an angle of about 120 deg 0 at each vertex. Over some faces of each hexagonal cell the strips are coplanar...

S. J. Kast

1985-01-01

60

Colloidal self-assembly: Interlocked octapods  

NASA Astrophysics Data System (ADS)

Suspensions of octapod-shaped nanocrystals are seen to spontaneously interlock into chains, which in turn aggregate side-by-side to form three-dimensional crystals. The observed hierarchical self-assembly can be explained by the octapod's shape and the solvent-tunable van der Waals interactions.

Rupich, Sara M.; Talapin, Dmitri V.

2011-11-01

61

Interlocking Ownership in the Korean Chaebol  

Microsoft Academic Search

This paper analyses how a dominant entrepreneur of the Korean chaebol is able to exercise control, despite having a tiny shareholding, through strategic interlocking ownership. The entrepreneur organises his intimate group, consisting of three clusters of in-house shareholders, and they together have controlling interests in only a few subsidiaries, mainly public companies. These central subsidiaries, as quasi-holding companies, control most

Dong-Woon Kim

2003-01-01

62

Radiation safety interlocks at the NSLS  

SciTech Connect

The function of the NSLS interlock systems is to insure that no one is in an area where there is hazardous radiation, and to turn off the radiation source if a person somehow gains access to such an area. The interlock systems for the high hazard areas meet the following design requirements: (1) The system is redundant, that is no single failure can render the system unsafe. This is done by providing 2 independent systems or circuits; (2) In so far as possible, the two circuits are physically different. This minimizes the possibility of related coincident failures; (3) The design is fail safe. This means that the most likely failure modes leave the system in a safe condition. For example, the following failures are safe: Loss of power in any part of the system, any combination of shorts to ground, and any combination of open circuits; and (4) The interlock system must be testable. Redundancy sometimes makes testing difficult, but testing schemes must be worked out, since an untested interlock is undependable.

Dickinson, T.

1985-07-01

63

Flexor Tendon Problems after Volar Plate Fixation of Distal Radius Fractures  

Microsoft Academic Search

Four cases of flexor tendon problems which developed after volar plate fixation of distal radius fractures are presented.\\u000a All cases were associated with close contact of the screws or distal edge of the plate with the flexor tendons. Poor bone\\u000a stock or multiple bone fragments allowing loosening of the plate or non-locking screws cause the hardware to irritate the\\u000a flexor

Mehdi N. Adham; Margaret Porembski; Christine Adham

2009-01-01

64

Comparison of Maxillary Molar Distalization with an Implant-Supported Distal Jet and a Traditional Tooth-Supported Distal Jet Appliance  

PubMed Central

Aim. To investigate and compare the efficiency of two appliances for molar distalization: the bone-anchored distal screw (DS) and the traditional tooth-supported distal jet (DJ) for molar distalization and anchorage loss. Methods. Tests (18 subjects) were treated with a DS and controls (18 subjects) were treated with a DJ. Lateral cephalograms were obtained before and at the end of molar distalization and were analysed. Shapiro Wilk test, unpaired t-test, and Wilcoxon rank-sum test were applied according to values distribution. The ? level was fixed at 0.05. Results. Maxillary first molars were successfully distalized into a Class I relationship in all patients. The mean molar distalization and treatment time were similar in both groups. The DS group exhibited a spontaneous distalization (2.1 ± 0.9?mm) of the first premolar with control of anchorage loss, distal tipping, extrusion, and skeletal changes. Conclusions. The DS is an adequate compliance-free distalizing appliance that can be used safely for the correction of Class II malocclusions. In comparison to the traditional DJ, the DS enables not only a good rate of molar distalization, but also a spontaneous distalization of the first premolars.

Cozzani, Mauro; Pasini, Marco; Zallio, Francesco; Ritucci, Robert; Mutinelli, Sabrina; Mazzotta, Laura; Giuca, Maria Rita; Piras, Vincenzo

2014-01-01

65

Modelling Railway Interlocking Tables Using Coloured Petri Nets  

NASA Astrophysics Data System (ADS)

Interlocking tables are the functional specification defining the routes, on which the passage of the train is allowed. Associated with the route, the states and actions of all related signalling equipment are also specified. This paper formally models the interlocking tables using Coloured Petri Nets (CPN). The CPN model comprises two parts: Signaling Layout and Interlocking Control. The Signaling Layout part is used to simulate the passage of the train. It stores geographic information of the signalling layout in tokens. The Interlocking Control part models actions of the controller according to the functions specified in the interlocking tables. The arc inscriptions in the model represent the content of the interlocking tables. Following our modelling approach we can reuse the same CPN net structure to model any new or modified interlocking system regardless of its size. Experimental results are presented to provide increased confidence in the model correctness.

Vanit-Anunchai, Somsak

66

[Screw fixation of craniocervical junction].  

PubMed

In recent years an increase has been observed of the use of screw techniques for the fixation of the craniocervical junction. For clinical use two techniques have been introduced: (1) transarticular screw fixation, and (2) transpedicular screw fixation. In the former the screw is inserted through the C2 lateral mass, the fissure of the C1-C2 joint, and the C1 lateral mass. (2) in the latter the screw is inserted into the C2 pedicle and anchored in C2 vertebral body. Transarticular or pedicle screws can be easily connected to longitudinal elements such as rods or plates, and combined with lateral mass screws of the remaining cervical vertebrae or occipital screws. In comparison to sublaminar wiring or interlaminar clamping the screw techniques: (a) strengthen the stiffness of the construct and speed up fusion, (b) allow fixation in the absence or deficiency of laminae as a result of trauma or laminectomy, and (c) can selectively include only the affected segments. Increased construct stiffness is due to deep anchorage of the screw in bone providing thus a solid grip on the vertebra. Both techniques require preoperative assessment of the course of the vertebral artery using imaging methods. In about 18% of cases abnormal course of the artery precludes screw use. Pedicle screw insertion requires direct control of the medial and superior walls of C2 pedicle with dissector introduced into the vertebral canal, which requires removal of the atlantoaxial ligament. Additional control can be achieved with lateral fluoroscopy. The entry point for transarticular screw is on the lateral mass of the odontoid 2-3 mm laterally to the medial margin of C2 facet and 2-3 mm above the C1/C2 articular fissure. The screw trajectory is 0-10 degrees in horizontal plane and towards the anterior C1 tuberculum in sagittal plane. PMID:10791042

Maciejczak, A; Radek, A

1999-01-01

67

Mechanically interlocked single-wall carbon nanotubes.  

PubMed

Extensive research has been devoted to the chemical manipulation of carbon nanotubes. The attachment of molecular fragments through covalent-bond formation produces kinetically stable products, but implies the saturation of some of the C-C double bonds of the nanotubes. Supramolecular modification maintains the structure of the SWNTs but yields labile species. Herein, we present a strategy for the synthesis of mechanically interlocked derivatives of SWNTs (MINTs). In the key rotaxane-forming step, we employed macrocycle precursors equipped with two ?-extended tetrathiafulvalene SWNT recognition units and terminated with bisalkenes that were closed around the nanotubes through ring-closing metathesis (RCM). The mechanically interlocked nature of the derivatives was probed by analytical, spectroscopic, and microscopic techniques, as well as by appropriate control experiments. Individual macrocycles were observed by HR?STEM to circumscribe the nanotubes. PMID:24729452

de Juan, Alberto; Pouillon, Yann; Ruiz-González, Luisa; Torres-Pardo, Almudena; Casado, Santiago; Martín, Nazario; Rubio, Ángel; Pérez, Emilio M

2014-05-19

68

Cannulated screws for odontoid screw fixation and atlantoaxial transarticular screw fixation. Technical note.  

PubMed

Cannulated screw systems use thin Kirschner wires (K-wires) that have been drilled into the bone to direct screw trajectories accurately into small bone fragments. Use of the K-wires avoids overdrilling the pilot holes and allows fixation of adjacent bone fragments during screw insertion. Hollow tools and hollow screws are inserted into the bone over the K-wires. Cannulated screw fixation is useful in the cervical spine to stabilize odontoid fractures and to treat atlantoaxial instability. This report describes techniques for successful cannulated screw insertion and methods to minimize complications. Cannulated screws have several distinct advantages compared to noncannulated screws: 1) the K-wires guide the screw position into the bone; 2) the K-wire trajectory can be repositioned easily if the original trajectory was not ideal; 3) the K-wires allow continuous fixation of adjacent unstable bone fragments; and 4) the K-wires prevent migration of unstable bone fragments during screw insertion. Complications associated with the K-wire (breakage, repositioning, and advancement) can be minimized using precise operative techniques, a specialized tool system, and intraoperative fluoroscopic monitoring. A unique cannulated screw tool system was developed specifically for upper cervical fixation to allow percutaneous drilling using long tunneling devices, tissue sheaths, drill guides, and long K-wires. These tools allow delivery of cannulated fracture-fixation screws at a low angle to the spine through long soft-tissue trajectories. Cannulated screws have significant advantages compared to noncannulated screws for fixation of the unstable cervical spine. PMID:7490629

Dickman, C A; Foley, K T; Sonntag, V K; Smith, M M

1995-12-01

69

Comparison of migration behavior between single and dual lag screw implants for intertrochanteric fracture fixation  

PubMed Central

Background Lag screw cut-out failure following fixation of unstable intertrochanteric fractures in osteoporotic bone remains an unsolved challenge. This study tested if resistance to cut-out failure can be improved by using a dual lag screw implant in place of a single lag screw implant. Migration behavior and cut-out resistance of a single and a dual lag screw implant were comparatively evaluated in surrogate specimens using an established laboratory model of hip screw cut-out failure. Methods Five dual lag screw implants (Endovis, Citieffe) and five single lag screw implants (DHS, Synthes) were tested in the Hip Implant Performance Simulator (HIPS) of the Legacy Biomechanics Laboratory. This model simulated osteoporotic bone, an unstable fracture, and biaxial rocking motion representative of hip loading during normal gait. All constructs were loaded up to 20,000 cycles of 1.45 kN peak magnitude under biaxial rocking motion. The migration kinematics was continuously monitored with 6-degrees of freedom motion tracking system and the number of cycles to implant cut-out was recorded. Results The dual lag screw implant exhibited significantly less migration and sustained more loading cycles in comparison to the DHS single lag screw. All DHS constructs failed before 20,000 cycles, on average at 6,638 ± 2,837 cycles either by cut-out or permanent screw bending. At failure, DHS constructs exhibited 10.8 ± 2.3° varus collapse and 15.5 ± 9.5° rotation around the lag screw axis. Four out of five dual screws constructs sustained 20,000 loading cycles. One dual screw specimens sustained cut-out by medial migration of the distal screw after 10,054 cycles. At test end, varus collapse and neck rotation in dual screws implants advanced to 3.7 ± 1.7° and 1.6 ± 1.0°, respectively. Conclusion The single and double lag screw implants demonstrated a significantly different migration resistance in surrogate specimens under gait loading simulation with the HIPS model. In this model, the double screw construct provided significantly greater resistance against varus collapse and neck rotation in comparison to a standard DHS lag screw implant.

Kouvidis, George K; Sommers, Mark B; Giannoudis, Peter V; Katonis, Pavlos G; Bottlang, Michael

2009-01-01

70

Interlocking egg-crate type grid assembly  

SciTech Connect

A spacer grid assembly for supporting nuclear fuel pins in a closely-spaced array is described comprising: (a) a first grid strip comprising segments, disposed at an angle to each other with alternate segments being substantially parallel to each other, each of the segments carrying at least one dimple for contacting the fuel pins; (b) a second grid strip comprising segments disposed at an angle to each other with alternate segments being substantially parallel to each other, each alternate segment of the second strip carrying a resilient contact for contacting the fuel pins; (c) a third grid strip comprising segments disposed at an angle to each other with alternate segments being substantially parallel to each other, each of the segments of the third strip carrying at least one dimple for contacting the fuel pins; and (d) interlocking means formed on the grid strips for interlocking the first and third grid strips with the second grid strip to form an array of grid cells having a hexagonal cross section and the segments of the first and third grid strips are substantially coplanar. The locking means include first tabs positioned on alternate segments of the first and third grid strips for interlocking with first slots formed on other alternate segments of the second grid strips that do not carry the resilient contacts.

Kast, S.J.

1987-12-22

71

How necessary is monitoring to interlock program success?  

PubMed

Objective: Numerous studies have demonstrated that vehicle alcohol ignition interlocks installed on the cars of impaired-driving offenders reduce recidivism by approximately two-thirds in comparison to similar offenders whose licenses have been suspended. An unresolved issue is the extent to which the effectiveness of interlock programs can be improved by close monitoring of the offenders' performance while in the program. This article describes 5 types of monitoring currently being used in interlock programs in the United States. Methods: The programs reviewed vary from those that simply ensure that the interlock is on the offender's vehicle and functioning, to those that use the interlock log data to extend the length of time the offender is required to be in the interlock program, and those that use the interlock data to initiate special monitoring and treatment programs that must be completed before removal of the interlock device. The strengths and limitations of each type of program are described. Also reviewed are current technological developments that appear to be leading to the development of fully automated interlock monitoring systems. Results: Initial evidence shows that more intensive monitoring provides benefits in improved performance on the interlock, as indicated by fewer high blood alcohol concentration (BAC) breath tests when attempting to drive. Although effective, supervision that is more intensive increases government program costs. Conclusions: The relative cost-effectiveness of the differing types of monitoring requires investigation. Treatment programs need to be integrated with the interlock installation period. New technologies can potentially reduce interlock offender monitoring costs and effectiveness. Integrating treatment with the interlock could have postinterlock benefits. PMID:24380634

Voas, Robert B; Taylor, Eileen; Kelley-Baker, Tara

2014-10-01

72

Guidewire Breakage: An Unusual Complication of Anterior Odontoid Cannulated Screw Fixation  

PubMed Central

The preferred treatment of a type II odontoid fracture is anterior odontoid screw fixation to preserve the cervical spine range of movement. This case report describes an unusual complication of guidewire breakage during anterior odontoid cannulated screw fixation for a 52-year-old patient who presented with a type II odontoid fracture after a motor vehicle accident. The distal segment of the guidewire was bent over the tip of the cannulated odontoid screw and broke off during guidewire withdrawal. The three months follow-up computed tomography examination of the cervical spine showed acceptable screw placement, good odontoid process alignment with incomplete fusion, and no migration of the fractured segment of the guidewire. It is recommended that the guidewire be withdrawn once the cannulated screw is passed through the fractured site into the odontoid process and a new guidewire be used in each surgical procedure instead of been reused to avoid metal stress fatigue that can result in easy breakage.

Bin-Nafisah, Sharaf; Almusrea, Khaled; Alfawareh, Mohamed

2011-01-01

73

Strength comparison of allogenic bone screws, bioabsorbable screws, and stainless steel screw fixation.  

PubMed

Allogenic bone screws are new to the fixation market and have yet to be tested against current fixation materials. An in vitro comparison of the same sizes of stainless steel, bioabsorbable, and allogenic bone screws was undertaken to assess screw resistance to the forces of bending, pullout, and shear. Using aluminum plates to support the screws, forces up to 1000 Newtons were applied to six to eight samples of each type of screw. During each test, stainless steel screws withstood the maximum force that could be exerted by the testing apparatus without failing (bending, 113.9 +/- 11.8 N mean +/- SE; pullout 999.1 +/- 33.7 N; and shear, 997.5 +/- 108.8 N). In each test, compared to bioabsorbable screws, allogenic bone screws failed faster (pullout, allogenic: 12.4 +/- 1.1 seconds vs. bioabsorbable, 120.6 +/- 13.8 seconds; p = .001; bending, allogenic: 53.4 +/- 4.8 seconds vs. bioabsorbable, 201.9 +/- 11.1 seconds; p = .001; shear, allogenic 13.5 +/- 1.4 seconds vs. bioabsorbable, 43.8 +/- 0.9 seconds; p = .001) under equivalent (pullout: bioabsorbable, 385.0 +/- 18.4 N vs. allogenic, 401.0 +/- 35.9 N; p = .001) or lower (bending, allogenic: 4.7 +/- 0.2 N vs. bioabsorbable, 11.0 +/- 0.9 N; p = .675; shear, allogenic: 312.1 +/- 15.5 N vs. bioabsorbable 680.9 +/- 8.5 N; p = .001) loads, and in a highly variable fashion. Overall, the bioabsorbable screws withstood the forces of bending, pullout, and shear better than the allogenic screws, and stainless steel screws outperformed both bioabsorbable and allogenic screws. Despite these results, allogenic screws could still be useful in compliant patients who would benefit from their osteoconductive properties. PMID:11858609

Rano, James A; Savoy-Moore, Ruth T; Fallat, Lawrence M

2002-01-01

74

Operative treatment of distal radius fractures.  

PubMed

The incidence of distal radius fractures is increasing together with the average age of population. Intra-articular incongruity is the most probable cause of unsatisfactory outcome of distal radius fractures in younger and more active patients. Thus, the main goal in the treatment of distal radius fractures should be restoration of articular congruence. A computed tomography (CT) is recommended to help surgeon in preoperative planning in the treatment of comminuted intra-articular fractures. New implants have been designed to provide stable enough fixation for early mobilisation after surgery and to lower rather high complication rates related to conventional fixation methods such as external fixation and dorsal plating. The most common complications related to volar fixed angle plating such as flexor and extensor tendon problems, median nerve neuropathy, and screw diplacement into the radiocarpal joint are surgeon related and are avoidable with proper education. More randomized prospective studies are needed to prove superiority of any fixation method to another. PMID:19211382

Vasenius, J

2008-01-01

75

Low noise lead screw positioner  

NASA Technical Reports Server (NTRS)

A very precise and low noise lead screw positioner, for positioning a retroreflector in an interferometer is described. A gas source supplies inert pressurized gas, that flows through narrow holes into the clearance space between a nut and the lead screw. The pressurized gas keeps the nut out of contact with the screw. The gas flows axially along the clearance space, into the environment. The small amount of inert gas flowing into the environment minimizes pollution. By allowing such flow into the environment, no seals are required between the end of the nut and the screw.

Perkins, Gerald S. (inventor)

1986-01-01

76

18 CFR 45.9 - Automatic authorization of certain interlocking positions.  

Code of Federal Regulations, 2013 CFR

...authorization of certain interlocking positions. 45.9 Section 45.9 Conservation...APPLICATION FOR AUTHORITY TO HOLD INTERLOCKING POSITIONS § 45.9 Automatic authorization of certain interlocking positions. (a) Applicability....

2013-04-01

77

49 CFR 236.312 - Movable bridge, interlocking of signal appliances with bridge devices.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Movable bridge, interlocking of signal appliances with bridge devices. 236.312 Section 236.312...Interlocking Standards § 236.312 Movable bridge, interlocking of signal appliances with...

2013-10-01

78

49 CFR 1242.58 - Operating signals and interlockers, operating drawbridges, highway crossing protection (accounts...  

Code of Federal Regulations, 2013 CFR

...interlockers, operating drawbridges, highway crossing protection (accounts XX-51-59...interlockers, operating drawbridges, highway crossing protection (accounts XX-51-59...signals, interlockers, drawbridges and highway crossings are...

2013-10-01

79

49 CFR 1242.58 - Operating signals and interlockers, operating drawbridges, highway crossing protection (accounts...  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Operating signals and interlockers, operating...ACCOUNTS, RECORDS AND REPORTS SEPARATION OF COMMON OPERATING EXPENSES...Expenses-Transportation § 1242.58 Operating signals and interlockers, operating...segment on which the common signals, interlockers,...

2009-10-01

80

49 CFR 1242.58 - Operating signals and interlockers, operating drawbridges, highway crossing protection (accounts...  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Operating signals and interlockers, operating...ACCOUNTS, RECORDS AND REPORTS SEPARATION OF COMMON OPERATING EXPENSES...Expenses-Transportation § 1242.58 Operating signals and interlockers, operating...segment on which the common signals, interlockers,...

2010-10-01

81

Mechanically interlocked gold and silver nanoparticles using metallosupramolecular catenane chemistry.  

PubMed

We have employed the toolbox of metallosupramolecular chemistry to mechanically interlock gold and silver nanoparticles. A specifically designed PEGthiol-functionalized bis(phenanthroline)copper(I) complex acts to 'catenate' the nanoparticles. The interlocked assemblies were characterised by three complementary techniques: DLS, SERS and TEM. PMID:21264434

Otter, Carl A; Patty, Philipus J; Williams, Martin A K; Waterland, Mark R; Telfer, Shane G

2011-03-01

82

An experimental study of the failure modes of the Gamma Locking Nail and AO Dynamic Hip Screw under static loading: a cadaveric study.  

PubMed

The sliding compression screw is widely regarded as the optimum treatment for intertrochanteric fractures of the femur, allowing bone fragments to impact until a bony support has been established across the fracture site. This study carried out biomechanical, cadaveric tests to establish the influence of direct static loading situations on the modes of failure of the Gamma Nail compared with the Dynamic Hip Screw (DHS). Clinical studies report DHS failures of lag screws cutting-out, bending of the lag screws and cortical screws pulling out causing plate loosening. Gamma Nail failures include lag screw cut-out or fractures of the femoral shaft around the distal locking screws or nail tip. In this study each failure mode has been isolated, to establish the loads to failure under various fracture configurations. The biomechanical results indicated that the intramedullary Gamma Locking Nail can be recommended over a standard DHS in cases of subtrochanteric fracture or conditions of very poor bone quality. PMID:9338885

Haynes, R C; Pöll, R G; Miles, A W; Weston, R B

1997-07-01

83

Influence of screw length and diameter on tibial strain energy density distribution after anterior cruciate ligament reconstruction  

NASA Astrophysics Data System (ADS)

Postoperative tunnel enlargement has been frequently reported after anterior cruciate ligament (ACL) reconstruction. Interference screw, as a surgical implant in ACL reconstruction, may influence natural loading transmission and contribute to tunnel enlargement. The aims of this study are (1) to quantify the alteration of strain energy density (SED) distribution after the anatomic single-bundleACL reconstruction; and (2) to characterize the influence of screw length and diameter on the degree of the SED alteration. A validated finite element model of human knee joint was used. The screw length ranging from 20 to 30mm with screw diameter ranging from 7 to 9mm were investigated. In the post-operative knee, the SED increased steeply at the extra-articular tunnel aperture under compressive and complex loadings, whereas the SED decreased beneath the screw shaft and nearby the intra-articular tunnel aperture. Increasing the screw length could lower the SED deprivation in the proximal part of the bone tunnel; whereas increasing either screw length or diameter could aggravate the SED deprivation in the distal part of the bone tunnel. Decreasing the elastic modulus of the screw could lower the bone SED deprivation around the screw. In consideration of both graft stability and SED alteration, a biodegradable interference screw with a long length is recommended, which could provide a beneficial mechanical environment at the distal part of the tunnel, and meanwhile decrease the bone-graft motion and synovial fluid propagation at the proximal part of the tunnel. These findings together with the clinical and histological factors could help to improve surgical outcome, and serve as a preliminary knowledge for the following study of biodegradable interference screw.

Yao, Jie; Kuang, Guan-Ming; Wong, DuoWai-Chi; Niu, Wen-Xin; Zhang, Ming; Fan, Yu-Bo

2014-03-01

84

Influence of screw length and diameter on tibial strain energy density distribution after anterior cruciate ligament reconstruction  

NASA Astrophysics Data System (ADS)

Postoperative tunnel enlargement has been frequently reported after anterior cruciate ligament (ACL) reconstruction. Interference screw, as a surgical implant in ACL reconstruction, may influence natural loading transmission and contribute to tunnel enlargement. The aims of this study are (1) to quantify the alteration of strain energy den sity (SED) distribution after the anatomic single-bundle ACL reconstruction; and (2) to characterize the influence of screw length and diameter on the degree of the SED alteration. A validated finite element model of human knee joint was used. The screw length ranging from 20 to 30mm with screw diameter ranging from 7 to 9 mm were investigated. In the post-operative knee, the SED increased steeply at the extra-articular tunnel aperture under compressive and complex loadings, whereas the SED decreased beneath the screw shaft and nearby the intra-articular tunnel aperture. Increasing the screw length could lower the SED deprivation in the proximal part of the bone tunnel; whereas increasing either screw length or diameter could aggravate the SED deprivation in the distal part of the bone tunnel. Decreasing the elastic modulus of the screw could lower the bone SED deprivation around the screw. In consideration of both graft stability and SED alteration, a biodegradable interference screw with a long length is recommended, which could provide a beneficial mechanical environment at the distal part of the tunnel, and meanwhile decrease the bone-graft motion and synovial fluid propagation at the proximal part of the tunnel. These findings together with the clinical and histological factors could help to improve surgical outcome, and serve as a preliminary knowledge for the following study of biodegradable interference screw. [Figure not available: see fulltext.

Yao, Jie; Kuang, Guan-Ming; Wong, Duo Wai-Chi; Niu, Wen-Xin; Zhang, Ming; Fan, Yu-Bo

2014-04-01

85

Orientation of the "Lisfranc screw".  

PubMed

The reduction and stabilization of diastases between the medial cuneiform and the base of second metatarsal after a Lisfranc ligament injury is a crucial objective in the open reduction and internal fixation of these injuries. To achieve this objective, a single screw is used. The present practice is to insert the screw directed from the medial cuneiform bone into the base of the second metatarsal. This technique trick describes an easier method of insertion of the screw and one that possibly provides a better fixation. PMID:22549028

Panchbhavi, Vinod K

2012-11-01

86

Multidisciplinary design optimization of lumbar transpedicular screws  

Microsoft Academic Search

Some of the complications associated with the use of transpedicular screws for spinal fusions include the large diameters of the screws and screw breakagein vivo. Recent advances in multidisciplinary design optimization techniques have provided a unique approach to incorporate the structural, biological, and manufacturing disciplines involved in the design process of spinal screws, allowing the development of smaller and safer

H. A. Serhan; C. L. Bloebaum; G. J. Bennett

1995-01-01

87

The path of screw insertion for stabilization of the scapholunate joint: a cadaveric study.  

PubMed

The aim of this study was to determine the path of screw placement to avoid breaching the articular surface of both lunate and scaphoid bones at the radiocarpal and midcarpal joints. An Acutrak screw was inserted into the right scapholunate joint of ten cadavers starting immediately distal to the tip of the radial styloid and aiming for the tip of the ulnar styloid. The articular surfaces of the scaphoid and lunate bones in all ten cadavers were exposed and examined. A computed tomography (CT) scan of four wrists was performed. Eight of the ten cadavers had no perforation or destruction of the articular surfaces. Screw stabilization of the scapholunate joint can be performed without perforation or destruction of the lunate or scaphoid surfaces. We recommend that if this form of fixation is being used then the screw should be inserted commencing at the radial styloid tip and aiming for ulnar styloid tip, under radiological guidance. PMID:24641760

Flannery, O M; Murphy, L C; Dockery, P; O'Sullivan, M E

2014-01-01

88

Surgical treatment of distal biceps rupture.  

PubMed

Rupture of the distal biceps tendon accounts for 10% of all biceps brachii ruptures. Injuries typically occur in the dominant elbow of men aged 40 to 49 years during eccentric contraction of the biceps. Degenerative changes, decreased vascularity, and tendon impingement may precede rupture. Although nonsurgical management is an option, healthy, active persons with distal biceps tendon ruptures benefit from early surgical repair, gaining improved strength in forearm supination and, to a lesser degree, elbow flexion. Biomechanical studies have tested the strength and displacement of various repairs; the suspensory cortical button technique exhibits maximum peak load to failure in vitro, and suture anchor and interosseous screw techniques yield the least displacement. Surgical complications include sensory and motor neurapraxia, infection, and heterotopic ossification. Current trends in postoperative rehabilitation include an early return to motion and to activities of daily living. PMID:20190104

Sutton, Karen M; Dodds, Seth D; Ahmad, Christopher S; Sethi, Paul M

2010-03-01

89

34. Boston switch interlocking tower. Central Falls, Providence Co., RI. ...  

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

34. Boston switch interlocking tower. Central Falls, Providence Co., RI. Sec. 4116, mp 190.40. - Northeast Railroad Corridor, Amtrak route between CT & MA state lines, Providence, Providence County, RI

90

Refining the maintenance techniques for Interlocking Concrete Paver GIs - abstract  

EPA Science Inventory

Surface clogging adversely affects the performance of Interlocking Concrete Pavements (ICP) by reducing their ability to infiltrate stormwater runoff. Determining the correct methods for remedial maintenances is crucial to recovering and maintaining efficient ICP performance. T...

91

Unilateral molar distalization with a modified slider.  

PubMed

Although there are numerous publications on bilateral non-compliance molar distalization appliances, there is limited information on problems such as asymmetrical unilateral Class II malocclusions. The aim of the present investigation was to examine the distalization of molars unilaterally in patients with a unilateral Class II molar relationship utilizing a Keles Slider, designed without a bite plane. Ten girls (mean age 13.94 +/- 2.13 years) and seven boys (mean age 13.12 +/- 1.51 years) comprised the study material. Following insertion of the appliance, the patients were seen monthly and the screw was reactivated every 2 months. After a super-Class I molar relationship was achieved, the appliance was removed and the molars were stabilized with a Nance appliance for 2 months before the second-phase of orthodontic treatment. The Nance appliance was maintained in the palate until the end of canine distalization. Lateral cephalometric radiographs were obtained before and immediately after insertion of the molar distalizer. The results showed that the maxillary first molars were distalized bodily on average by 2.85 mm. The maxillary first premolars moved forward bodily 2 mm and were extruded 2.03 mm. In all, 1.32 mm of protrusion, 1.12 mm of extrusion, and 1.79 degrees of proclination of the upper incisors were observed. The mandibular incisors and mandibular molars erupted 0.83 and 0.95 mm, respectively. The unilateral Keles Slider distalized molars successfully to a Class I molar relationship. PMID:16648210

Sayinsu, Korkmaz; Isik, Fulya; Allaf, Ferdi; Arun, Tülin

2006-08-01

92

49 CFR 1242.17 - Signals and interlockers (accounts XX-17-19 and XX-18-19).  

Code of Federal Regulations, 2010 CFR

... 2009-10-01 false Signals and interlockers (accounts...ACCOUNTS, RECORDS AND REPORTS SEPARATION OF COMMON OPERATING EXPENSES...Structures § 1242.17 Signals and interlockers (accounts...tracks on which the common signals and interlockers are...

2009-10-01

93

49 CFR 1242.17 - Signals and interlockers (accounts XX-17-19 and XX-18-19).  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 false Signals and interlockers (accounts...ACCOUNTS, RECORDS AND REPORTS SEPARATION OF COMMON OPERATING EXPENSES...Structures § 1242.17 Signals and interlockers (accounts...tracks on which the common signals and interlockers are...

2010-10-01

94

In vitro evaluation of conventional and locking miniplate\\/screw systems for the treatment of mandibular angle fractures  

Microsoft Academic Search

This in vitro study evaluated the influence of the type of miniplate and the number of screws installed in the proximal and distal segments on the stability and resistance of Champy's osteosynthesis in mandibular angle fractures. Sixty polyurethane hemimandibles with bone-like consistency were randomly assigned to four groups (n=15) and sectioned in the mandibular angle region to simulate fracture. The

P. D. Ribeiro-Junior; O. Magro-Filho; K. A. Shastri; M. B. Papageorge

2010-01-01

95

PLC-based interlock system for superconducting magnets  

SciTech Connect

Conventional interlock systems rely heavily on hard-wired electromagnetic relays. Although this approach is well understood and has proven to be reliable, several drawbacks plague the designer as well as the repairman. If larger systems have to be implemented in relay logic, the complexity limit is soon reached; the systems become too bulky, and wiring expenses sky-rocket; moreover, the intelligence of those designs is limited in such a way that desirable features such as self-tests have to be left out. Additionally, relay interlocks are inherently inflexible: if the configuration of the system they protect has to change, a disproportional amount of time, work and money has to be invested in order to adapt the hard-wiring of the interlock system to the new requirements. Repair work is often unnecessarily delayed due to the lack of adequate documentation.

Agostini, R.C.; Barker, L.; Hodgers, J.; Reagan, D.; Walz, H.V. (Stanford Univ., CA (USA))

1989-10-01

96

Metallurgical examination of gun barrel screws  

SciTech Connect

The examination was conducted to determine the extent of degradation that had occurred after a series of firings; these screws prevent live rounds of ammunition from being loaded into the firing chamber. One concern is that if the screw tip fails and a live round is accidentally loaded into the chamber, a live round could be fired. Another concern is that if the blunt end of the screw begins to degrade by cracking, pieces could become small projectiles during firing. All screws used in firing 100 rounds or more exhibited some degree degradation, which progressively worsened as the number of rounds fired increased. (SEM, metallography, x-ray analysis, and microhardness were used.) Presence of cracks in these screws after 100 fired rounds is a serious concern that warrants the discontinued use of these screws. The screw could be improved by selecting an alloy more resistant to thermal and chemical degradation.

Bird, E.L.; Clift, T.L.

1996-06-01

97

Anion-directed formation and degradation of an interlocked metallohelicate.  

PubMed

Although there are many examples of catenanes, those of more complex mechanically interlocked molecular architectures are rare. Additionally, little attention has been paid to the degradation of such interlocked systems into their starting complexes, although formation and degradation are complementary phenomena and are equally important. Interlocked metallohelicate, [(Pd(2)L(4))(2)](8+) (2(8+)), is a quadruply interlocked molecular architecture consisting of two mechanically interlocked monomers, [Pd(2)L(4)](4+) (1(4+)). 2(8+) has three internal cavities, each of which encapsulates one NO(3)(-) ion (1:3 host-guest complex, 2?(NO(3)|NO(3)|NO(3))(5+)) and is characterized by unusual thermodynamic stability. However, both the driving force for the dimerization and the origin of the thermodynamic stability remain unclear. To clarify these issues, BF(4)(-), PF(6)(-), and OTf(-) have been used to demonstrate that the dimerization is driven by the anion template effect. Interestingly, the stability of 2(8+) strongly depends on the encapsulated anions (2?(NO(3)|NO(3)|NO(3))(5+) ? 2?(BF(4)|BF(4)|BF(4))(5+)). The origins of this differing thermodynamic stability have been shown through detailed investigations to be due to the differences in the stabilization of the interlocked structure by the host-guest interaction and the size of the anion. We have found that 2-naphthalenesulfonate (ONs(-)) induces the monomerization of 2?(NO(3)|NO(3)|NO(3))(5+) via intermediate 2?(ONs|NO(3)|ONs)(5+), which is formed by anion exchange. On the basis of this finding, and using p-toluenesulfonate (OTs(-)), the physical separation of 2?(NO(3)|NO(3)|NO(3))(5+) and 1(4+) as OTs(-) salt was accomplished. PMID:22663382

Sekiya, Ryo; Fukuda, Morihiko; Kuroda, Reiko

2012-07-01

98

Strong interlocking of nonconvex particles in random packings  

NASA Astrophysics Data System (ADS)

We present a numerical study of random packings made of nonconvex grains. These particles are built by the agglomeration of overlapping spheres in order to control their sphericity ?. The contact number C is found to be much larger than the coordination number Z, providing a significant difference with convex grains. The packing properties are found to be highly dependent on the morphological parameters of the grains : packing fractions as low as 0.3 have been reached. More importantly, the way nonconvex grains develop multiple contacts, i.e., interlocking, is found to be a relevant effect in such packings. Interlocking provides more stability to loose packings.

Ludewig, F.; Vandewalle, N.

2012-05-01

99

A Case of Pedicle Screw Loosening Treated by Modified Transpedicular Screw Augmentation with Polymethylmethacrylate  

PubMed Central

We report a case of pedicle screw loosening treated by modified transpedicular screw augmentation technique using polymethylmethacrylate (PMMA), which used the anchoring effect of hardened PMMA. A 56-year-old man who had an L3/4/5 fusion operation 3 years ago complained of continuous low back pain after this operation. The computerized tomography showed a radiolucent halo around the pedicle screw at L5. We augmented the L5 pedicle screw with modified pedicle screw augmentation technique using PMMA and performed an L3/4/5 pedicle screw fixation without hook or operation field extension. This modified technique is a kind of transpedicular stiffness augmentation using PMMA for the dead space around the loosed screw. After filling the dead space with 1-2 cc of PMMA, we inserted a small screw. Once the PMMA hardened, we removed the small screw and inserted a thicker screw along the existing screw threading to improve the pedicle screws' pullout strength. At 10 months' follow-up, x-ray showed strong fusion of L3/4/5. The visual analogue scale (VAS) of his back pain was improved from 9 to 5. This modified transpedicular screw augmentation with PMMA using anchoring effect is a simple and effective surgical technique for pedicle screw loosening. However, clinical analyses of long-term follow-up and biomechanical studies are needed.

Kang, Suk-Hyung; Kim, Kyoung-Tae; Park, Seung Won

2011-01-01

100

1. ENVIRONMENT, FROM NORTHWEST, SHOWING B&P INTERLOCKING TOWER AND POWER ...  

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

1. ENVIRONMENT, FROM NORTHWEST, SHOWING B&P INTERLOCKING TOWER AND POWER SUBSTATIONS - Baltimore & Potomac Interlocking Tower, Adjacent to AMTRAK railroad tracks in block bounded by Howard Street, Jones Falls Expressway, Maryland Avenue & Falls Road, Baltimore, Independent City, MD

101

Evaluation of a program to motivate impaired driving offenders to install ignition interlocks  

Microsoft Academic Search

Approximately 30,000 alcohol ignition interlocks, which are designed to prevent the operation of a vehicle if the driver has been drinking, are in use in the US and Canada. Ignition interlock programs are also being initiated in Sweden and Australia. The best-controlled studies that are currently available suggest that ignition interlocks are effective in reducing impaired driving recidivism while on

Robert B. Voas; Kenneth O. Blackman; A. Scott Tippetts; Paul R. Marques

2001-01-01

102

Evaluation of a program to motivate impaired driving offenders to install ignition interlocks  

Microsoft Academic Search

Approximately 30,000 alcohol ignition interlocks, which are designed to prevent the operation of a vehicle if the driver has been drinking, are in use in the US and Canada. Ignition interlock programs are also being initiated in Sweden and Australia. The best-controlled studies that are currently available suggest that ignition interlocks are effective in reducing impaired driving recidivism while on

Robert B. Voas; Kenneth O. Blackman; A. Scott Tippetts; Paul R. Marques

2002-01-01

103

Description of a system for interlocking elevated temperature mechanical tests  

NASA Astrophysics Data System (ADS)

Long term mechanical creep and fatigue testing at elevated temperatures requires reliable systems with safeguards to prevent destruction of equipment, loss of data, and negative environmental impacts. Toward this goal, a computer controlled system has been developed and built for interlocking tests run on elevated temperature mechanical test facilities. Sensors for water flow, water pressure, water leakage, temperature, power, and hydraulic status are monitored to control specimen heating equipment through solid state relays and water solenoid valves. The system is designed to work with the default interlocks present in the RF generators and mechanical tests systems. Digital hardware consists of two National Instruments I/O boards mounted in a Macintosh IIci computer. Software is written in National Instruments LabVIEW. Systems interlocked include two MTS closed loop servo controlled hydraulic test frames, one with an RF generator and one with both an RF generator and a quartz lamp furnace. Control for individual test systems is modularized making the addition of more systems simple. If any of the supporting utilities fail during tests, heating systems, chill water, and hydraulics are powered down, minimizing specimen damage and eliminating equipment damage. The interlock control is powered by an uninterruptible power supply. Upon failure the cause is documented in an ASCII file.

Schmale, D. T.; Poulter, G. A.

1995-07-01

104

How Does Learning Intent Affect Interlocking Directorates Dynamic?  

ERIC Educational Resources Information Center

Purpose: Literature on board interlocks agrees that these inter-organizational ties are effective channels to exchange information and share knowledge. However, studies that consider the nature and the amount of knowledge that firms exchange are still relatively absent. Filling this gap, this paper aims to identify four types of mechanisms that…

Simoni, Michele; Caiazza, Rosa

2012-01-01

105

An applicable topology-independent model for railway interlocking systems  

Microsoft Academic Search

In this article, two decision models for railway interlocking systems are presented. The first – for the case that the turnouts have spring switches- and the second – for the case that the turnouts should not be trailed through a switch set against-. In both cases, the algorithm is independent of the topology of the station and is based on

Eugenio Roanes-Lozano; Luis M. Laita

1998-01-01

106

Flammable gas interlock spoolpiece flow response test plan and procedure  

SciTech Connect

The purpose of this test plan and procedure is to test the Whittaker electrochemical cell and the Sierra Monitor Corp. flammable gas monitors in a simulated field flow configuration. The sensors are used on the Rotary Mode Core Sampling (RMCS) Flammable Gas Interlock (FGI), to detect flammable gases, including hydrogen and teminate the core sampling activity at a predetermined concentration level.

Schneider, T.C., Fluor Daniel Hanford

1997-02-13

107

Description of a system for interlocking elevated temperature mechanical tests  

SciTech Connect

Long term mechanical creep and fatigue testing at elevated temperatures requires reliable systems with safeguards to prevent destruction of equipment, loss of data and negative environmental impacts. Toward this goal, a computer controlled system has been developed and built for interlocking tests run on elevated temperature mechanical test facilities. Sensors for water flow, water pressure, water leakage, temperature, power and hydraulic status are monitored to control specimen heating equipment through solid state relays and water solenoid valves. The system is designed to work with the default interlocks present in the RF generators and mechanical tests systems. Digital hardware consists of two National Instruments 1/0 boards mounted in a Macintosh IIci computer. Software is written in National Instruments LabVIEW. Systems interlocked include two MTS closed loop servo controlled hydraulic test frames, one with an RF generator and one with both an RF generator and a quartz lamp furnace. Control for individual test systems is modularized making the addition of more systems simple. If any of the supporting utilities fail during tests, heating systems, chill water and hydraulics are powered down, minimizing specimen damage and eliminating equipment damage. The interlock control is powered by an uninterruptible power supply. Upon failure the cause is documented in an ASCII file.

Schmale, D.T.; Poulter, G.A.

1995-07-01

108

Slippage between screwdriver and bone screw.  

PubMed

Cortical 3.5-mm stainless steel screws with hexagonal heads and corresponding screwdrivers from two manufacturers were investigated. Measurement of dimensions and torsional testing were done to study slippage between the screw and the driver bit. There were only small differences in dimensions between the manufacturers. Ultimate torque values obtained were at the level of 2.7 N-m where reaming of the screw socket took place. Additional rotation resulted in approximately (1/2) of the maximum torque. Subsequent torque testing in the opposite direction, corresponding to removal of the screw, revealed that the torque values were equally low in that direction. Additional insertion and removal of bone screws with hexagonal sockets are hampered after only one episode of slippage. It is justified to consider new shapes of drive bits and corresponding screw head sockets, such as a fluted multiedge configuration. PMID:12439282

Behring, Jon K; Gjerdet, Nils R; Mølster, Anders

2002-11-01

109

Construction and Biomechanical Properties of PolyAxial Self-Locking Anatomical Plate Based on the Geometry of Distal Tibia  

PubMed Central

In order to provide scientific and empirical evidence for the clinical application of the polyaxial self-locking anatomical plate, 80 human tibias from healthy adults were scanned by spiral CT and their three-dimensional images were reconstructed using the surface shaded display (SSD) method. Firstly, based on the geometric data of distal tibia, a polyaxial self-locking anatomical plate for distal tibia was designed and constructed. Biomechanical tests were then performed by applying axial loading, 4-point bending, and axial torsion loading on the fracture fixation models of fresh cadaver tibias. Our results showed that variation in twisting angles of lateral tibia surface was found in various segments of the distal tibia. The polyaxial self-locking anatomical plate was constructed based on the geometry of the distal tibia. Compared to the conventional anatomical locking plate, the polyaxial self-locking anatomical plate of the distal tibia provides a better fit to the geometry of the distal tibia of the domestic population, and the insertion angle of locking screws can be regulated up to 30°. Collectively, this study assesses the geometry of the distal tibia and provides variable locking screw trajectory to improve screw-plate stability through the design of a polyaxial self-locking anatomical plate.

Liang, Weiguo; Ye, Weixiong; Ye, Dongping; Zhou, Ziqiang; Chen, Zhiguang; Li, Aiguo; Xie, Zong-Han; Zhang, Lihai; Xu, Jiake

2014-01-01

110

A Comparison of Functional Outcomes After Metallic and Bioabsorbable Interference Screw Fixations in Arthroscopic ACL Reconstructions  

PubMed Central

Introduction: Anterior Cruciate Ligament (ACL) is as one of the most frequently injured ligaments in the modern contact sports scenario. Graft fixations can be achieved during anterior cruciate ligament (ACL) reconstructions by using either bioabsorbable screws or metal screws. The objective of this study was to compare the functional outcomes after bioabsorbable and metallic interference screw fixations in arthroscopic anterior cruciate ligament reconstructions done by using hamstring grafts. Materials and Methods: This was a prospective, randomized study. Patients in Group 1 received bioabsorbable interference screws and patients in Group 2 received metallic interference screws. Arthroscopic assisted, anterior cruciate ligament reconstructions with the use of hamstring grafts which were fixed proximally with endobuttons and distally with bioabsorbable or metallic interference screws, were undertaken. Progress in functional outcomes was assessed by using Mann Whitney U- test. Functional outcomes in the two groups were compared by using independent t-test. Observation and Results: In each group, there were statistically significant improvements in functional outcomes over successive follow-ups, which were seen on basis on Mann-Whitney U-test. The comparison of functional outcomes between the two groups, done by using independent t-test, showed no statistically significant differences between the two groups at 3 months, 6 months and 1 year of follow-up. p-value <0.05 was considered to be significant in our study. Conclusion: In our prospective study of comparison of functional outcomes between bioabsorbable and metallic interference screws in arthroscopic anterior cruciate ligament reconstuctions, which were evaluated by using Tegner activity scale and Lysholm knee scoring scale for a period of 1 year, no statistically significant difference was found. However, further authentication is required by doing long term studies.

Rai, Deepak K; Kannampilly, Antony J

2014-01-01

111

[Torque measurement of self-threading bone screws. Test procedure for new surgical screws].  

PubMed

Different systems of self-cutting screws are tested by a measuring instrument to test the torsional strain. Modern methods of measuring techniques are applied to get results of the torsional force and the torque by screwing into the bones. To get a self-cutting screw system several methods of biomechanical properties must be applied. A variety of quality tests, of biomechanical screws, are used, before performing the operations, that flaws may be detected. PMID:2639546

Heinl, T; Neumayer, B

1989-12-01

112

Intra-operative screw trimming in direct screw fixation of the odontoid process fracture — Technical note  

Microsoft Academic Search

Summary For a satisfactory direct screw fixation of fractures of the odontoid process it is necessary to use a screw of the proper total length and thread length, but such an optimal ready-made screw is not always available. The authors describe a technique of intra-operative screw trimming using a high-speed diamond drill. This adjustment is easily and quickly performed. It

T. Hasegawa; K. Yamano; Y. Hamada; T. Miyamori

1992-01-01

113

Biodegradable Interference Screw Fixation Exhibits Pull-Out Force and Stiffness Similar to Titanium Screws  

Microsoft Academic Search

Recently, increased interest in biodegradable interference screws for bone-tendon-bone graft fixation has led to numerous screws becoming available. The implants are made from different polymers and have different designs, which might influence their mechanical properties. Several studies have reported a wide range of mechanical results for these screws using different biomechanical models. The aim of the present study is to

Andreas Weiler; Henning J. Windhagen; Michael J. Raschke; Andrea Laumeyer; Reinhard F. G. Hoffmann

1998-01-01

114

A novel screw guiding method with a screw guide template system for posterior C-2 fixation.  

PubMed

Object Accurate insertion of C-2 cervical screws is imperative; however, the procedures for C-2 screw insertion are technically demanding and challenging, especially in cases of C-2 vertebral abnormality. The purpose of this study is to report the effectiveness of the tailor-made screw guide template (SGT) system for placement of C-2 screws, including in cases with abnormalities. Methods Twenty-three patients who underwent posterior spinal fusion surgery with C-2 cervical screw insertion using the SGT system were included. The preoperative bone image on CT was analyzed using multiplanar imaging software. The trajectory and depth of the screws were designed based on these images, and transparent templates with screw guiding cylinders were created for each lamina. During the operation, after templates were engaged directly to the laminae, drilling, tapping, and screwing were performed through the templates. The authors placed 26 pedicle screws, 12 pars screws, 6 laminar screws, and 4 C1-2 transarticular screws using the SGT system. To assess the accuracy of the screw track under this system, the deviation of the screw axis from the preplanned trajectory was evaluated on postoperative CT and was classified as follows: Class 1 (accurate), a screw axis deviation less than 2 mm from the planned trajectory; Class 2 (inaccurate), 2 mm or more but less than 4 mm; and Class 3 (deviated), 4 mm or more. In addition, to assess the safety of the screw insertion, malpositioning of the screws was also evaluated using the following grading system: Grade 0 (containing), a screw is completely within the wall of the bone structure; Grade 1 (exposure), a screw perforates the wall of the bone structure but more than 50% of the screw diameter remains within the bone; Grade 2 (perforation), a screw perforates the bone structures and more than 50% of the screw diameter is outside the pedicle; and Grade 3 (penetration), a screw perforates completely outside the bone structure. Results In total, 47 (97.9%) of 48 screws were classified into Class 1 and Grade 0, whereas 1 laminar screw was classified as Class 3 and Grade 2. Mean screw deviations were 0.36 mm in the axial plane (range 0.0-3.8 mm) and 0.30 mm in the sagittal plane (range 0.0-0.8 mm). Conclusions This study demonstrates that the SGT system provided extremely accurate C-2 cervical screw insertion without configuration of reference points, high-dose radiation from intraoperative 3D navigation, or any registration or probing error evoked by changes in spinal alignment during surgery. A multistep screw placement technique and reliable screw guide cylinders were the key to accurate screw placement using the SGT system. PMID:24785974

Kaneyama, Shuichi; Sugawara, Taku; Sumi, Masatoshi; Higashiyama, Naoki; Takabatake, Masato; Mizoi, Kazuo

2014-08-01

115

Articular fractures of the distal humerus.  

PubMed

Distal humeral fractures represent 2% of all adult elbow fractures. Injury mechanisms include high-energy trauma with skin involvement, and low energy trauma in osteoporotic bone. Treatment goals are anatomical restoration in young, high-demand patients and quick recovery of activities of daily living in the elderly. Complete fractures are relatively easy to diagnose, but partial intra-articular fractures are not. The clinical diagnosis must take into account potential complications such as open injuries and ulnar nerve trauma. Standard X-rays with additional distraction series in the operating room are sufficient in complete articular fracture cases. Partial intra-articular fractures will need CT scan and 3D reconstruction to fully evaluate the involved fragments. SOFCOT, AO/OTA and Dubberley classifications are the most useful for describing fractures and selecting treatment. Surgery is the optimal treatment and planning is based on fracture type. Complete fractures are treated using a posterior approach. Triceps management is a function of fracture lines and type of fixation planned. Constructs using two plates at 90° or 180° are the most stable, with additional frontal screw for intercondylar fractures. Elbow arthroplasty may be indicated in selected patients, having severely communited distal humerus fractures and osteoporotic bone. Open fractures make fixation and wound management more challenging and unfortunately have poorer outcomes. Other complications are elbow stiffness, non-union, malunion and heterotopic ossification. PMID:24461911

Bégué, T

2014-02-01

116

Pullout strength of pedicle screws with cement augmentation in severe osteoporosis: A comparative study between cannulated screws with cement injection and solid screws with cement pre-filling  

Microsoft Academic Search

BACKGROUND: Pedicle screws with PMMA cement augmentation have been shown to significantly improve the fixation strength in a severely osteoporotic spine. However, the efficacy of screw fixation for different cement augmentation techniques, namely solid screws with retrograde cement pre-filling versus cannulated screws with cement injection through perforation, remains unknown. This study aimed to determine the difference in pullout strength between

Lih-Huei Chen; Ching-Lung Tai; De-Mei Lee; Po-Liang Lai; Yen-Chen Lee; Chi-Chien Niu; Wen-Jer Chen

2011-01-01

117

Tricorrectional bunionectomy with AO screw fixation.  

PubMed

A 16-month preliminary study was performed on 58 patients for corrective surgery of hallux abducto valgus, with AO4 screw fixation. The procedure is a modification of the bi-plane Austin procedure, called a tricorrectional bunionectomy. The authors present the procedure with objective and subjective findings. The principles of bone healing and internal fixation using AO screw fixation are discussed. PMID:2625507

Boggs, S I; Selner, A J; Roth, I E; Bernstein, A L

1989-01-01

118

Solar power units with screw expanders  

Microsoft Academic Search

A low-power solar electric generator based on a screw expander which drives an ac motor is presented. The choices of flat plate or concentrating Rankine or Brayton cycle, and an oil-injected screw expander motor in the development of the unit are examined, and the effects of Mediterranean and subtropical locations on plant performance are discussed. Results of solar engine performance

J. M. Merigoux; P. Pocard

1980-01-01

119

NATIONAL SYNCHROTRON LIGHT SOURCE MEDICAL PERSONNEL PROTECTION INTERLOCK  

SciTech Connect

This report is founded on reports written in April 1987 by Robert Hettel for angiography operations at the Stanford Synchrotron Research Laboratory (SSRL) and a subsequent report covering angiography operations at the National Synchrotron Light Source (NSLS); BNL Informal Report 47681, June 1992. The latter report has now been rewritten in order to accurately reflect the design and installation of a new medical safety system at the NSLS X17B2 beamline Synchrotron Medical Research Facility (SMERF). Known originally as the Angiography Personnel Protection Interlock (APPI), this system has been modified to incorporate other medical imaging research programs on the same beamline and thus the name has been changed to the more generic Medical Personnel Protection Interlock (MPPI). This report will deal almost exclusively with the human imaging (angiography, bronchography, mammography) aspects of the safety system, but will briefly explain the modular aspects of the system allowing other medical experiments to be incorporated.

BUDA,S.; GMUR,N.F.; LARSON,R.; THOMLINSON,W.

1998-11-03

120

Engineering interlocking DNA rings with weak physical interactions.  

PubMed

Catenanes are intriguing molecular assemblies for engineering unique molecular devices. The resident rings of a catenane are expected to execute unhindered rotation around each other, and to do so, they must have weak physical interactions with each other. Due to sequence programmability, DNA has become a popular material for nanoscale object engineering. However, current DNA catenanes, particularly in the single-stranded (ss) form, are synthesized through the formation of a linking duplex, which makes them less ideal as mobile elements for molecular machines. Herein we adopt a random library approach to engineer ssDNA [2] catenanes (two interlocked DNA rings) without a linking duplex. Results from DNA hybridization, double-stranded catenane synthesis and rolling circle amplification experiments signify that representative catenanes have weak physical interactions and are capable of operating as independent units. Our findings lay the foundation for exploring free-functioning interlocked DNA rings for the design of elaborate nanoscale machines based on DNA. PMID:24969435

Wu, Zai-Sheng; Shen, Zhifa; Tram, Kha; Li, Yingfu

2014-01-01

121

Metal-organic frameworks with dynamic interlocked components  

NASA Astrophysics Data System (ADS)

The dynamics of mechanically interlocked molecules such as rotaxanes and catenanes have been studied in solution as examples of rudimentary molecular switches and machines, but in this medium, the molecules are randomly dispersed and their motion incoherent. As a strategy for achieving a higher level of molecular organization, we have constructed a metal-organic framework material using a [2]rotaxane as the organic linker and binuclear Cu(II) units as the nodes. Activation of the as-synthesized material creates a void space inside the rigid framework that allows the soft macrocyclic ring of the [2]rotaxane to rotate rapidly, unimpeded by neighbouring molecular components. Variable-temperature 13C and 2H solid-state NMR experiments are used to characterize the nature and rate of the dynamic processes occurring inside this unique material. These results provide a blueprint for the future creation of solid-state molecular switches and molecular machines based on mechanically interlocked molecules.

Vukotic, V. Nicholas; Harris, Kristopher J.; Zhu, Kelong; Schurko, Robert W.; Loeb, Stephen J.

2012-06-01

122

116. Photocopied August 1978. NEW INTERLOCKING STEEL SHEET PILING AT ...  

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

116. Photocopied August 1978. NEW INTERLOCKING STEEL SHEET PILING AT PENSTOCK 52 IN THE FALL OF 1926. THE PILES FOR SUPPORTING THE HORIZONTAL ELEMENTS OF THE NEW FOREBAY APRON ARE IN PLACE BETWEEN THE NEW SHEET PILING AND THE FOREBAY WALL. VISIBLE BEYOND THE NEW SHEET PILING IS THE TIMBER SHEET PILING DRIVEN IN 1903 BY VON SCHON TO PREVENT WASHOUTS. (1006) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

123

Laser structuring of metal surfaces: Micro-mechanical interlocking  

NASA Astrophysics Data System (ADS)

Efficient micro-mechanical interlocking may be achieved on appropriately laser-structured surfaces. In this paper, we discuss the issues relevant for the laser-machining process, including the precision and the material removal rate. We investigate the surface morphology of stainless steel after irradiation by nanosecond laser pulses at different pulse energies and irradiation strategies. At the optimum operation parameters, we demonstrate that a high-average-power nanosecond laser provides a reasonable compromise between precision and production time.

Byskov-Nielsen, J.; Balling, P.

2009-03-01

124

Shareholding Interlocks in the Keiretsu, Japan's Financial Groups  

Microsoft Academic Search

Abstract Banks and insurance companies,in Japan have been more,inclined to hold stock directly and indirectly in clients that borrow more intensely from them, based on analysis of 1980 data. This evidence is consistent with the rationale for such stockholding being to resolve agency problems of debt. In carrying out this investigation a new measure,of indirect shareholding is developed. SHAREHOLDING INTERLOCKS

David Flath

125

Dimensional stability of cotton-spandex interlock structures under relaxation  

Microsoft Academic Search

In this study, dimensional characteristics of core spun cotton\\/spandex interlock structures with high, medium and low tightness\\u000a factors were studied under dry-, wet-, and full relaxation conditions. Results are compared with those for similar fabrics\\u000a knitted from 100 % cotton. Dimensional characteristics of samples of core-spun cotton\\/spandex and cotton are measured by considering\\u000a the changing of course-, wale- densities and

C. N. Herath; Bok Choon Kang; Han-Yong Jeon

2007-01-01

126

Biomechanical analysis of the mechanism of interlocking nail failure  

Microsoft Academic Search

From December 1986 to May 1989, 412 patients with 274 femoral and 144 tibial fractures were treated with Grosse-Kempf interlocking nails at our hospital. 324 cases (78.6%) were followed-up for at least 1 year (average 23 months). There were 13 breakages in the locking nails in femora and none in tibiae. The recorded incidence of breakage in the femur is

Chi-Chuan Wu; Chun-Hsiung Shih

1992-01-01

127

The influence of distal locking on the need for fibular plating in intramedullary nailing of distal metaphyseal tibiofibular fractures.  

PubMed

Using human cadaver specimens, we investigated the role of supplementary fibular plating in the treatment of distal tibial fractures using an intramedullary nail. Fibular plating is thought to improve stability in these situations, but has been reported to have increased soft-tissue complications and to impair union of the fracture. We proposed that multidirectional locking screws provide adequate stability, making additional fibular plating unnecessary. A distal tibiofibular osteotomy model performed on matched fresh-frozen lower limb specimens was stabilised with reamed nails using conventional biplanar distal locking (CDL) or multidirectional distal locking (MDL) options with and without fibular plating. Rotational stiffness was assessed under a constant axial force of 150 N and a superimposed torque of ± 5 Nm. Total movement, and neutral zone and fracture gap movement were analysed. In the CDL group, fibular plating improved stiffness at the tibial fracture site, albeit to a small degree (p = 0.013). In the MDL group additional fibular plating did not increase the stiffness. The MDL nail without fibular plating was significantly more stable than the CDL nail with an additional fibular plate (p = 0.008). These findings suggest that additional fibular plating does not improve stability if a multidirectional distal locking intramedullary nail is used, and is therefore unnecessary if not needed to aid reduction. PMID:24589796

Attal, R; Maestri, V; Doshi, H K; Onder, U; Smekal, V; Blauth, M; Schmoelz, W

2014-03-01

128

Neutral beam interlock system on TFTR using infrared pyrometry  

SciTech Connect

Although the region of the TFTR vacuum vessel wall which is susceptible to damage by neutral beam strike is armored with a mosaic of TiC-clad POCO graphite titles, at power deposition levels above 2.5 kW/cm/sup 2/ the armor surface temperature exceeds 1200/sup 0/C within 250 ms and itself becomes susceptible to damage. In order to protect the wall armor, a neutral beam interlock system based on infrared pyrometry measurement of the armor surface temperature was installed on TFTR. For each beamline, a three-fiber-optic telescope views three areas of approx.30 cm diameter centered on the armor hot spots for the three ion sources. Each signal is fiber-optic coupled to a remote 900 nm pyrometer which feeds analog signals to the neutral beam interrupt circuits. The pyrometer interlock system is designed to interrupt each of the twelve ion sources independently within 10 ms of the temperature exceeding a threshold settable in the range of 500 to 2300/sup 0/C. A description of the pyrometer interlock system and its performance will be presented.

Medley, S.S.; Kugel, H.W.; Kozub, T.A.; Lowrance, J.L.; Mastrocola, V.; Renda, G.; Young, K.M.

1986-06-01

129

Neutral beam interlock system on TFTR using infrared pyrometry  

SciTech Connect

Although the region of the Tokamak Fusion Test Reactor (TFTR) vacuum vessel wall which is susceptible to damage by neutral beam strike is armored with a mosaic of TiC-clad POCO graphite tiles, at power deposition levels above 2.5 kW/cm/sup 2/ the armor surface temperature exceeds 1200 /sup 0/C within 250 ms, and itself becomes susceptible to damage. In order to protect the wall armor, a neutral beam interlock system based on infrared pyrometry measurement of the armor surface temperature was installed on TFTR. For each beamline, a three-fiber-optic telescope views three areas of --30 cm diameter centered on the armor hot spots for the three ion sources. Each signal is fiber-optic coupled to a remote 900-nm pyrometer which feeds analog signals to the neutral beam interrupt circuits. The pyrometer interlock system is designed to interrupt each of the 12 ion sources independently within 10 ms of the temperature exceeding a threshold which can be set in the range of 500--2300 /sup 0/C. A description of the pyrometer interlock system and its performance will be presented.

Medley, S.S.; Kugel, H.W.; Kozub, T.A.; Lowrance, J.L.; Mastrocola, V.; Renda, G.; Young, K.M.

1986-08-01

130

Flammable gas interlock spoolpiece flow response test report  

SciTech Connect

The purpose of this test report is to document the testing performed under the guidance of HNF-SD-WM-TC-073, {ital Flammable Gas Interlock Spoolpiece Flow Response Test Plan and Procedure}. This testing was performed for Lockheed Martin Hanford Characterization Projects Operations (CPO) in support of Rotary Mode Core Sampling jointly by SGN Eurisys Services Corporation and Numatec Hanford Company. The testing was conducted in the 305 building Engineering Testing Laboratory (ETL). NHC provides the engineering and technical support for the 305 ETL. The key personnel identified for the performance of this task are as follows: Test responsible engineering manager, C. E. Hanson; Flammable Gas Interlock Design Authority, G. P. Janicek; 305 ETL responsible manager, N. J. Schliebe; Cognizant RMCS exhauster engineer, E. J. Waldo/J. D. Robinson; Cognizant 305 ETL engineer, K. S. Witwer; Test director, T. C. Schneider. Other support personnel were supplied, as necessary, from 305/306 ETL. The testing, on the flammable Gas Interlock (FGI) system spoolpiece required to support Rotary Mode Core Sampling (RMCS) of single shell flammable gas watch list tanks, took place between 2-13-97 and 2-25-97.

Schneider, T.C., Fluor Daniel Hanford

1997-03-24

131

[The monorail system--bone segment transport over unreamed interlocking nails].  

PubMed

A treatment protocol is demonstrated, consisting of an osteotomy, either proximal or distal, of the bone defect with subsequent segmental transport via an anteromedially (tibia) or laterally (femur) mounted AO external fixation over an unreamed interlocking nail (monorail system). Twenty patients were treated by this method with indications as follows: 13 had a segmental bone defect of the tibia, 3 of the femur. Three patients showed post-traumatic and postinfectious leg-length discrepancies and one was treated for hypertrophic non-union of the femur. Defect distance varied between 5 and 18.5 cm and average time for transport was 19,42 days/ cm for the tibial shaft, 15,93 days/cm for the femur. Two patients developed deep infection, which required change of treatment, removing the monorail system and application of an Ilizarov apparatus. Despite complications using the monorail system, all patients healed and no amputations were required. The monorail system can be used as an alternative to the Ilizarov method under certain criteria of patient selection; these criteria are shown by an algorithm for segmental bone defects without infection, respecting the soft-tissue status with or without neurovascular compromise. PMID:9035940

Oedekoven, G; Jansen, D; Raschke, M; Claudi, B F

1996-11-01

132

Improved extraction torque of hydroxyapatite-coated pedicle screws.  

PubMed

Loosening of the screws is a problem in instrumentation with pedicle screws. Coating with hydroxyapatite improves the holding characteristics for metal implants, but the possible effects on the anchorage of pedicle screws have not been described. In this study, seven patients were operated on with spinal instrumentation using four stainless steel pedicle screws. Hydroxyapatite-coated screws were used in either the upper or the lower of the instrumented levels. The insertion torque was measured. In four cases the screws were removed after 10-22 months and the extraction torque was measured. The mean insertion torque was found to be significantly greater in the hydroxyapatite-coated screws (107 Ncm) than in the standard screws (76 Ncm). In three cases, the extraction torque for the hydroxyapatite-coated screws exceeded the range for the torque wrench (600 Ncm), while the conventional screws were loose (< 5 Ncm). In one case, the extraction torque was 475 and 550 Ncm for the coated screws, and 5 and 25 Ncm for the conventional screws. The difference in extraction torque was significant. Hydroxyapatite coating was shown to have improved the purchase of pedicle screws very effectively. By using fully coated screws, as in the present study, extraction was extremely difficult compared to extraction of conventional stainless steel screws, which were regularly loose. By reducing the area of the screws that is coated, it may be possible to achieve an enhanced purchase while extraction will be easier when compared to fully coated screws. PMID:11189923

Sandén, B; Olerud, C; Johansson, C; Larsson, S

2000-12-01

133

Scarf osteotomy without screw fixation  

Microsoft Academic Search

The scarf osteotomy is now well recognised as reliable and effective to contribute to the correction of the majority of hallux\\u000a valgus. The challenge remains for the correction of severe deformities with metatarsus varus angle >18? and Distal Metatarsal\\u000a Articular Angle (DMAA) >15?. In order to significantly improve in 3D the metatarsal head displacements, our scarf design became more oblique,

M. Maestro

2007-01-01

134

Screw-released roller brake  

NASA Technical Reports Server (NTRS)

A screw-released roller brake including an input drive assembly, an output drive assembly, a plurality of locking sprags, a mechanical tripper nut for unlocking the sprags, and a casing therefor. The sprags consist of three dimensional (3-D) sprag members having pairs of contact surface regions which engage respective pairs of contact surface regions included in angular grooves or slots formed in the casing and the output drive assembly. The sprags operate to lock the output drive assembly to the casing to prevent rotation thereof in an idle mode of operation. In a drive mode of operation, the tripper is either self actuated or motor driven and is translated linearly up and down against a spline and at the limit of its travel rotates the sprags which unlock while coupling the input drive assembly to the output drive assembly so as to impart a turning motion thereto in either a clockwise or counterclockwise direction.

Vranish, John M. (Inventor)

1999-01-01

135

Distal radius fixation through a mini-invasive approach of 15 mm. PART 1: a series of 144 cases.  

PubMed

The volar Henry approach is becoming the gold standard for distal radius fracture fixation. It decreases the incidence of nonunion, limits complications especially complex regional pain syndrome (CRPS) type I, and allows early mobilization of the wrist. Nonetheless, it has some disadvantages such as the size of the incision, which is not esthetically pleasing, and the loss of ligamentotaxis. This is why some authors have developed a mini-invasive approach. The aim of this work was to evaluate the feasibility of the anterior mini-invasive approach of 15 mm in a clinical series of 144 cases of distal radius fracture. All patients were operated under regional anesthesia using the same techniques by five surgeons of the same team. According to the AO classification, there were 83 type A fractures, 2 type B, and 59 type C. A volar plate (Step One(®), Newclip Technics™, Haute-Goulaine, France) was used in all cases. The 2 proximal metaphyseal screws and the 2 distal central epiphyseal screws were monoaxial locking. The 2 distal ulnar and radial epiphyseal screws were placed in polyaxial locking at 20° angulation maximum. Skin closure without drainage was performed. No postoperative immobilization was prescribed, and patients were encouraged to use their upper limb immediately postoperative. No postoperative physiotherapy was prescribed. The mean follow-up was 4.1 months. The final size of the incision was on average 16.1 mm. Mean pain score was 1.8. The Quick DASH score was average 25. Average range of motion was more than 85 %, and global force of the hand was 67 % compared with contralateral side. On X-ray, the mean radial slope was 22°, the mean radial tilt was 8.3°, and the mean radioulnar variance/index was -0.4 mm. There were nine cases of CRPS type I, which all resolved. Specific complications included two secondary displacements and nine tenosynovitis cases. No tendon rupture was noted. Two intra-articular distal radioulnar joint screws had to be removed at 3 months. One epiphyseal screw required removal 1 month postoperative due to loosening. There were no intra-articular radiocarpal screws. Distal radius fracture fixation using a mini-invasive approach is a reliable and reproducible procedure with few complications. It allows anatomical reduction in the distal radius fractures including intra-articular ones. It can be associated with arthroscopy, scaphoid screw fixation or even percutaneous pinning. Thus, most traumatic lesions of the wrist bony or soft tissue can be treated through this mini-invasive approach. PMID:24258689

Lebailly, Frédéric; Zemirline, Ahmed; Facca, Sybille; Gouzou, Stéphanie; Liverneaux, Philippe

2014-08-01

136

Automated Checking and Visualization of Interlocks in the ISAC Control System  

Microsoft Academic Search

The EPICS based control system of the ISAC radioactive beam facility supervises several sub-systems, which are controlled by PLCs. Most of the devices are protected by non-trivial interlocks, which are implemented with ladder-logic software. Detailed information on interlock state and the individual interlock conditions are accessible for each device at the EPICS operator interface level. With the increasing number of

Rolf Keitel; R. Nussbaumer

2001-01-01

137

On-machine interlocking of 3D laminate structures for composites  

Microsoft Academic Search

By using an adjacent-layer interlocking method on a weaving machine, multi-layer preform structures are developed. The on-loom interlocking method eliminates the yarn breakage resulting from needle penetration which is the case for off-loom interlocking of fabric layers. The concept of this three-dimensional (3D) fabric design is to bind each pair of adjacent layers at one connecting point in every other

Sabit Adanur; C. Andrew Tam

1997-01-01

138

Distal tibiofibular radiological overlap  

PubMed Central

Objectives Overlap between the distal tibia and fibula has always been quoted to be positive. If the value is not positive then an injury to the syndesmosis is thought to exist. Our null hypothesis is that it is a normal variant in the adult population. Methods We looked at axial CT scans of the ankle in 325 patients for the presence of overlap between the distal tibia and fibula. Where we thought this was possible we reconstructed the images to represent a plain film radiograph which we were able to rotate and view in multiple planes to confirm the assessment. Results The scans were taken for reasons other than pathology of the ankle. We found there was no overlap in four patients. These patients were then questioned about previous injury, trauma, surgery or pain, in order to exclude underlying pathology. Conclusion We concluded that no overlap between the tibia and fibula may exist in the population, albeit in a very small proportion.

Sowman, B.; Radic, R.; Kuster, M.; Yates, P.; Breidiel, B.; Karamfilef, S.

2012-01-01

139

Combined S-1 and S-2 sacral alar-iliac screws as a salvage technique for pelvic fixation after pseudarthrosis and lumbosacropelvic instability: combined S-1 and S-2 sacral alar-iliac screws as a salvage technique for pelvic fixation after pseudarthrosis and lumbosacropelvic instability: technical note.  

PubMed

Lumbosacropelvic pseudarthrosis after long spinal fusions for treatment of adult degenerative scoliosis remains a challenging condition. Moreover, although pelvic fixation with iliac screws is widely used in deformity surgery to provide a biomechanically strong distal anchor for long thoracolumbar constructs, there are very few options available after failed pelvic fixation with iliac screws. The authors conducted a retrospective review of the surgical charts and imaging findings of patients subjected to revision surgery for lumbosacropelvic pseudarthrosis from August 2011 to August 2012. This review identified 5 patients in whom a salvage technique combining both S-1 and S-2 sacral alar-iliac (SAI) screws had been performed. In this technical note, the authors present a detailed anatomical discussion and an appraisal of the sequential intraoperative steps of this new technique involving a combination of S-1 and S-2 SAI screws. The discussion is illustrated with a surgical case in which this technique was used to treat a patient with pseudarthrosis that had developed after fixation with classic iliac screws. In conclusion, although S-2 SAI screws have previously been reported as an interesting alternative to classic iliac wing screws, this report is the first on the use of combined S-1 and S-2 SAI screws for pelvic fixation as a salvage technique for lumbosacropelvic instability. According to the reported experience, this technique provides a biomechanically robust construct for definitive pelvic fixation during revision surgeries in the challenging scenarios of pseudarthrosis and instability of the lumbosacropelvic region. PMID:23808582

Mattei, Tobias A; Fassett, Daniel R

2013-09-01

140

The effect of transpedicular screw misplacement on late spinal stability  

Microsoft Academic Search

Summary ¶ Background. In this article the authors investigated the consequences of misplaced thoracolumbar pedicle screws on late spinal stability. Method. This study consisted of 16 patients with screws in the proper position (Group A) and a further 16 patients with screw misplacement (Group B) who had previously undergone transpedicular screw fixation following thoracolumbar injury. The authors retrospectively evaluated the

S. C. Aç?kba?; F. Y. Arslan; M. R. Tuncer

2003-01-01

141

The biomechanics of guided growth: does screw size, plate size, or screw configuration matter?  

PubMed

Guided growth with the eight-plate is a commonly used technique to correct angular limb deformities in children. However, the optimal combination of plate size, screw size, and screw configuration has not been determined. Using osteotomized femoral sawbones and a rail frame, we developed a growth model to examine the effect of these variables at 6-month, 12-month, and 18-month growth increments. The mean annual coronal plane change was 11.3°. Screw size and plate size were not associated with the rate of angular correction. Screw configuration was important, with parallel screws resulting in optimal correction at all time points compared with divergent screws (P<0.05). PMID:24322536

Schoenleber, Scott J; Iobst, Christopher A; Baitner, Avi; Standard, Shawn C

2014-03-01

142

Fixed Bicortical Screw and Blade Implants as a Non-Standard Solution to an Edentulous (Toothless) Mandible  

PubMed Central

Aim This paper deals with the treatment of an atrophied toothless mandible with a fixing bridge carried by two non-standard implant systems. Methodology Four bicortical screws were implanted into the frontal part of the mandible and one implant on each side was placed into the distal area of the mandible as a support for a fixing bridge. Results During the years 2002 – 2007 the authors placed a total of 256 bicortical screw and 84 blade implants. During this period only four bicortical screws and one blade implant failed. The primary and secondary surgical success rate was therefore above 98%, while the prosthetic success rate was 100%. (Bridges which had to be re-fabricated due to implant failure were not taken into account.) Conclusion This approach is recommended as a highly successful and affordable option for a wide range of patients.

Strecha, Juraj; Jurkovic, Richard; Siebert, Tomas; Prachar, Patrik; Bartakova, Sonia

2010-01-01

143

Distal biceps tendon rupture  

Microsoft Academic Search

The authors report a rupture of the distal tendon of biceps brachii in a 42-year-old athlete. Magnetic resonance imaging confirmed the injury. Early surgical repair was performed by reinsertion of the tendon on the radial tuberosity according to modified Boyd-Anderson technique. Indomethacin was administered prophylactically. No complications were noted. At the latest follow-up, the patient had full elbow range of

Olga D. Savvidou; Panayiotis J. Papagelopoulos; Andreas F. Mavrogenis; Antonios A. Partsinevelos; Evangelos J. Karadimas; Demetrios S. Korres

2004-01-01

144

Minifragment screw fixation of oblique metacarpal fractures: a biomechanical analysis of screw types and techniques.  

PubMed

The lag screw technique has historically been a successful and accepted way to treat oblique metacarpal fractures. However, it does take additional time and involve multiple steps that can increase the risk of fracture propagation or comminution in the small hand bones of the hand. An alternate fixation technique uses bicortical interfragmentary screws. Other studies support the clinical effectiveness and ease of this technique. The purpose of this study is to biomechanically assess the strength of the bicortical interfragmentary screw versus that of the traditional lag screw. Using 48 cadaver metacarpals, oblique osteotomies were created and stabilized using one of four methods: 1.5 mm bicortical interfragmentary (IF) screw, 1.5 mm lag technique screw, 2.0 mm bicortical IF screw, or 2.0 mm lag technique screw. Biomechanical testing was performed to measure post cyclic displacement and load to failure. Data was analyzed using one-way analysis of variance (ANOVA). There was no significant difference among the fixation techniques with regard to both displacement and ultimate failure strength. There was a slight trend for a higher load to failure with the 2.0 mm IF screw and 2.0 mm lag screw compared to the 1.5 mm IF and 1.5 mm lag screws, but this was not significant. Our results support previously established clinical data that bicortical interfragmentary screw fixation is an effective treatment option for oblique metacarpal fractures. This technique has clinical importance because it is an option to appropriately stabilize the often small and difficult to control fracture fragments encountered in metacarpal fractures. PMID:18780019

Liporace, Frank A; Kinchelow, Tosca; Gupta, Salil; Kubiak, Erik N; McDonnell, Matthew

2008-12-01

145

Minifragment Screw Fixation of Oblique Metacarpal Fractures: A Biomechanical Analysis of Screw Types and Techniques  

PubMed Central

The lag screw technique has historically been a successful and accepted way to treat oblique metacarpal fractures. However, it does take additional time and involve multiple steps that can increase the risk of fracture propagation or comminution in the small hand bones of the hand. An alternate fixation technique uses bicortical interfragmentary screws. Other studies support the clinical effectiveness and ease of this technique. The purpose of this study is to biomechanically assess the strength of the bicortical interfragmentary screw versus that of the traditional lag screw. Using 48 cadaver metacarpals, oblique osteotomies were created and stabilized using one of four methods: 1.5 mm bicortical interfragmentary (IF) screw, 1.5 mm lag technique screw, 2.0 mm bicortical IF screw, or 2.0 mm lag technique screw. Biomechanical testing was performed to measure post cyclic displacement and load to failure. Data was analyzed using one-way analysis of variance (ANOVA). There was no significant difference among the fixation techniques with regard to both displacement and ultimate failure strength. There was a slight trend for a higher load to failure with the 2.0 mm IF screw and 2.0 mm lag screw compared to the 1.5 mm IF and 1.5 mm lag screws, but this was not significant. Our results support previously established clinical data that bicortical interfragmentary screw fixation is an effective treatment option for oblique metacarpal fractures. This technique has clinical importance because it is an option to appropriately stabilize the often small and difficult to control fracture fragments encountered in metacarpal fractures.

Liporace, Frank A.; Gupta, Salil; Kubiak, Erik N.; McDonnell, Matthew

2008-01-01

146

3D mapping of safe and danger zones in the maxilla and mandible for the placement of intermaxillary fixation screws.  

PubMed

Intermaxillary (IMF) screws feature several advantages over other devices used for intermaxillary fixation, but using cone beam computed tomography (CBCT) scans to determine the safe and danger zones to place these devices for all patients can be expensive. This study aimed to determine the optimal interradicular and buccopalatal/buccolingual spaces for IMF screw placement in the maxilla and mandible. The CBCT volumetric data of 193 patients was used to generate transaxial slices between the second molar on the right to the second molar on the left in both arches. The mean interradicular and buccopalatal/buccolingual distances and standard deviation values were obtained at heights of 2, 5, 8 and 11 mm from the alveolar bone crest. An IMF screw with a diameter of 1.0 mm and length of 7 mm can be placed distal to the canines (2 - 11 mm from the alveolar crest) and less than 8 mm between the molars in the maxilla. In the mandible, the safest position is distal to the first premolar (more than 5 mm) and distal to the second premolar (more than 2 mm). There was a significant difference (p<0.05) between the right and left quadrants. The colour coding 3D template showed the safe and danger zones based on the mesiodistal, buccopalatal and buccolingual distances in the maxilla and mandible.The safest sites for IMF screw insertion in the maxilla were between the canines and first premolars and between the first and second molars. In the mandible, the safest sites were between the first and second premolars and between the second premolar and first molar. However, the IMF screw should not exceed 1.0 mm in diameter and 7 mm in length. PMID:24367643

Purmal, Kathiravan; Alam, Mohammad Khursheed; Pohchi, Abdullah; Abdul Razak, Noor Hayati

2013-01-01

147

Screw pull-out force is dependent on screw orientation in an anterior cervical plate construct.  

PubMed

Two common justifications for orienting cervical screws in an angled direction is to increase pull-out strength and to allow use of longer screws. This concept is widely taught and has guided implant design. Fixed versus variable angle systems may offer strength advantages. The purpose of our study is to test the influence of screw orientation and plate design on the maximum screw pull-out load. Variable and fixed angle 4.0 x 15 mm and 4.0 x 13 mm self-tapping screws were used to affix a Medtronic Atlantis cervical plate to polyurethane foam bone samples (density 0.160/cm). This synthetic product is a model of osteoporotic cancellous bone. The fixed angle screws can only be placed at 12 degrees convergent to the midline and 12 degrees in the cephalad/caudal ("12 degrees up and in") direction. Three groups were tested: (1) all fixed angle screws, (2) variable angle, all screws 12 degrees up and in, (3) variable angle, all screws 90 degrees to the plate. Plate constructs were pulled off with an Instron DynaMight 8841 servohydrolic machine measuring for maximum screw pull-out force. There was no difference between group 1, fixed angle (288.4 +/- 37.7 N) (mean +/- SD) and 2, variable angle group (297.7 +/- 41.31 N P< or =0.73). There was a significant increase in maximum pull-out force to failure for the construct with all screws at 90 degrees (415.2+/-17.4 N) compared with all screws 12 degrees "up and in" (297.4 +/- 41.3 N, P< or =0.0016). Group 3 done with 13 mm screws, showed a trend toward better pull-out strength, compared to group 2 w/15 mm screws (345.2 +/- 20.5 vs. 297.4 +/- 41.3, P< or =0.06). In this plate pull-out model, screw orientation influences maximum force to failure. When all 4 screws are 90 degrees to the plate the construct has the greatest ability to resist pullout. Fixed angle designs show no advantage over variable angle. These findings are contrary to current teaching. PMID:17607102

DiPaola, Christian P; Jacobson, Justin A; Awad, Hani; Conrad, Bryan P; Rechtine, Glenn R

2007-07-01

148

National Synchrotron Light Source angiography personnel protection interlock  

SciTech Connect

This document has been written to describe the safety system operation at the NSLS X17B2 beamline Synchrotron Medical Research Facility (SMERF). The angiography exposure process involves scanning a patient up and down through dual fixed-position x-ray beams; exposure is controlled by opening and closing a fast-acting Safety Shutter mechanism at precise times in relation to the up and down motion of the scan chair. The fast-acting Safety Shutter mechanism is the primary radiation-stopping element protecting the patient while the chair is at rest and while it is reversing directions during the scan. Its fail-safe and fast operation is essential for the safety of the patient. Operation of X17B2 as a human subject angiography station necessitates the implementation of a personnel protection interlock system that, in conjunction with the Safety Shutters: permits safe access to the patient exposure area while the synchrotron radiation beam is illuminating the upstream dual energy monochromator; allows a patient to be imaged by the monochromatized beam under the supervision of a Responsible Physician, with scan chair motion and precision shutter actuation regulated by an angiography control computer, while providing a suitable number of safeguards against accidental radiation exposure; has different modes of operation to accommodate equipment set-up, test, and calibration; and patient exposure; and ensures the quick extinction of the beam if a potentially unsafe condition is detected. The interlock system which performs these safety functions is called the Angiography Personnel Protection Interlock (APPI). The APPI Document is organized such that the level of detail changes from a general overview to detailed engineering drawings of the hardware system.

Gmuer, N.; Larson, R.; Thomlinson, W.

1992-06-01

149

National Synchrotron Light Source medical personnel protection interlock  

SciTech Connect

This report is founded on reports written in April 1987 by Robert Hettel for angiography operations at the Stanford Synchrotron Research Laboratory (SSRL) and a subsequent report covering angiography operations at the National Synchrotron Light Source (NSLS); BNL Informal Report 47681, June 1992. The latter report has now been rewritten in order to accurately reflect the design and installation of a new medical safety system at the NSLS X17B2 beamline Synchrotron Medical Research Facility (SMERF). Known originally as the Angiography Personnel Protection Interlock (APPI), this system has been modified to incorporate other medical imaging research programs on the same beamline and thus the name has been changed to the more generic Medical Personnel Protection Interlock (MPPI). This report will deal almost exclusively with the human imaging (angiography, bronchography, mammography) aspects of the safety system, but will briefly explain the modular aspects of the system allowing other medical experiments to be incorporated. This MPPI report is organized such that the level of detail changes from a general overview to detailed engineering drawings of the hardware system. The general overview is presented in Section 1.0, MPPI Operational Mode and Procedures. The various MPPI components are described in detail in Section 2.0. Section 3.0 presents some simplified logic diagrams and accompanying text. This section was written to allow readers to become familiar with the logic system without having to work through the entire set of detailed engineering drawings listed in the Appendix. Detailed logic specifications are given in Section 4.0. The Appendix also contains copies of the current MPPI interlock test procedures for Setup and Patient Modes.

Buda, S.; Gmuer, N.F.; Larson, R.; Thomlinson, W.

1998-11-01

150

Coracoid fracture combined with distal clavicle fracture without coracoclavicular ligament rupture: A case report  

PubMed Central

Distal clavicle fracture accompanied by coracoid process one is a rare injury. Surgical and/or conservative treatments are proposed. We report the case of a 49-year-old woman presenting a distal clavicle fracture associated with a coracoid process one due to a fall on the left shoulder. Both injuries are treated surgically. Per operatively, and through an anterior “strap” approach, the coracoclavicular ligament was seen intact. The distal clavicle fracture was fixed with K-wires and cerclage and the coracoid process was secured by a screw. Active-assisted rehabilitation of the shoulder was initiated 3 weeks after surgery. At the last follow-up of twelve months, the patient had painless full shoulder functions and X-rays show bony union. Early recovery to normal life is possible with surgical treatment in patients with distal clavicle fracture combined with coracoid fracture.

Allagui, M.; Koubaa, M.; Aloui, I.; Zrig, M.; Hamdi, M.F.; Abid, A.

2013-01-01

151

Stable three-dimensional metallic carbon with interlocking hexagons.  

PubMed

Design and synthesis of 3D metallic carbon that is stable under ambient conditions has been a long-standing dream. We predict the existence of such phases, T6- and T14-carbon, consisting of interlocking hexagons. Their dynamic, mechanical, and thermal stabilities are confirmed by carrying out a variety of state-of-the-art theoretical calculations. Unlike the previously studied K4 and the simple cubic high pressure metallic phases, the structures predicted in this work are stable under ambient conditions. Equally important, they may be synthesized chemically by using benzene or polyacenes molecules. PMID:24191020

Zhang, Shunhong; Wang, Qian; Chen, Xiaoshuang; Jena, Puru

2013-11-19

152

Stable three-dimensional metallic carbon with interlocking hexagons  

PubMed Central

Design and synthesis of 3D metallic carbon that is stable under ambient conditions has been a long-standing dream. We predict the existence of such phases, T6- and T14-carbon, consisting of interlocking hexagons. Their dynamic, mechanical, and thermal stabilities are confirmed by carrying out a variety of state-of-the-art theoretical calculations. Unlike the previously studied K4 and the simple cubic high pressure metallic phases, the structures predicted in this work are stable under ambient conditions. Equally important, they may be synthesized chemically by using benzene or polyacenes molecules.

Zhang, Shunhong; Wang, Qian; Chen, Xiaoshuang; Jena, Puru

2013-01-01

153

Photovoltaic module and interlocked stack of photovoltaic modules  

DOEpatents

One embodiment relates to an arrangement of photovoltaic modules configured for transportation. The arrangement includes a plurality of photovoltaic modules, each photovoltaic module including a frame having at least a top member and a bottom member. A plurality of alignment features are included on the top member of each frame, and a plurality of alignment features are included on the bottom member of each frame. Adjacent photovoltaic modules are interlocked by the alignment features on the top member of a lower module fitting together with the alignment features on the bottom member of an upper module. Other embodiments, features and aspects are also disclosed.

Wares, Brian S.

2012-09-04

154

Reconstruction after wide resection of the entire distal fibula in malignant bone tumours.  

PubMed

In this study we present a series of patients (n?=?11) with resection of the entire distal fibula in the case of sarcoma or metastasis. Moreover, we describe a new method to restore ankle stability with a tibiotalocalcaneal arthrodesis using a retrograde hindfoot nail (n?=?4) in contrast to tibiotalar arthrodesis with screws (n?=?5). The screw fixation failed in two patients due to osteopoenic bone. The crucial benefits of an arthrodesis with a retrograde nail are a stable arthrodesis, intramedullary stabilisation of the tibia and avoidance of extrinsic material in the wound area. An arthrodesis with a retrograde nail is a good alternative for reconstruction after a wide distal fibula resection. The additional arthrodesis of the subtalar joint was not associated with worse functional results in the MSTS and TESS scores. PMID:20039038

Dieckmann, Ralf; Ahrens, Helmut; Streitbürger, Arne; Budny, Tymoteusz Borys; Henrichs, Marcel-Philipp; Vieth, Volker; Gebert, Carsten; Hardes, Jendrik

2011-01-01

155

Distal interphalangeal joint arthrodesis using nitinol intramedullary fixation implants: X-fuse implants for DIP arthrodesis.  

PubMed

Arthrodesis has been shown to be a successful operative procedure for the treatment of intractable pain, instability, and deformity of the distal interphalangeal joint of the fingers, and interphalangeal joint of the thumb. Multiple fixation techniques have been used in the past including Kirschner wires, tension bands, headless screws, or lag screws. Clinical results are generally acceptable, but complication rates have been reported to vary between 10% and 20%. Complications include nonunion, pain, malunion, infection, nerve injury, and protruding hardware. The aim of this study is to describe an alternative technique for arthrodesis of the distal interphalangeal joint of the fingers or interphalangeal joint of the thumb using Nitinol implants for intramedullary fixation with a minimal complication rate. PMID:23970200

Seitz, William H; Marbella, Marko E

2013-09-01

156

Treatment of Symptomatic Distal Interphalangeal Joint Arthritis with Percutaneous Arthrodesis: a Novel Technique in Select Patients  

PubMed Central

Arthrodesis of the distal interphalangeal (DIP) joint is a reliable means of achieving pain relief in a symptomatic DIP joint afflicted by a variety of degenerative, inflammatory, or posttraumatic conditions. Successful arthrodesis is more reproducible when rigid compression of the joint is achieved. The emergence of an increasing number of commercially available headless or variable pitch compression screws reflects the growing trend among hand surgeons to utilize rigid stabilization of the DIP joint so that motion at more proximal levels can be initiated immediately without affecting arthrodesis rates. Successful closed percutaneous DIP arthrodesis can be achieved in a patient with hypertrophic osteoarthropathy, passively correctable deformity, and patients at increased risk for perioperative soft tissue complications associated with open arthrodesis. We present a novel percutaneous DIP fusion technique utilizing a cannulated headless compression screw in a select group of patients. The sagittal plane diameters of the distal and middle phalanges are templated. Cannulated headless compression screws, 2.4 and 3.0 mm, with short or long terminal threads at the leading end of the screw are selected based upon patient-specific anatomic considerations. Pain-free status and radiographic fusion were achieved in both patients (gout arthropathy, n?=?1; posttraumatic arthritis, n?=?1) at an average of 6 weeks postoperatively. Our current indications, along with pearls and pitfalls with this technique, are reviewed. In select patients, this percutaneous DIP joint arthrodesis is advantageous in comparison with open fusion techniques.

Ruchelsman, David E.; Hazel, Antony

2010-01-01

157

Treatment of symptomatic distal interphalangeal joint arthritis with percutaneous arthrodesis: a novel technique in select patients.  

PubMed

Arthrodesis of the distal interphalangeal (DIP) joint is a reliable means of achieving pain relief in a symptomatic DIP joint afflicted by a variety of degenerative, inflammatory, or posttraumatic conditions. Successful arthrodesis is more reproducible when rigid compression of the joint is achieved. The emergence of an increasing number of commercially available headless or variable pitch compression screws reflects the growing trend among hand surgeons to utilize rigid stabilization of the DIP joint so that motion at more proximal levels can be initiated immediately without affecting arthrodesis rates. Successful closed percutaneous DIP arthrodesis can be achieved in a patient with hypertrophic osteoarthropathy, passively correctable deformity, and patients at increased risk for perioperative soft tissue complications associated with open arthrodesis. We present a novel percutaneous DIP fusion technique utilizing a cannulated headless compression screw in a select group of patients. The sagittal plane diameters of the distal and middle phalanges are templated. Cannulated headless compression screws, 2.4 and 3.0 mm, with short or long terminal threads at the leading end of the screw are selected based upon patient-specific anatomic considerations. Pain-free status and radiographic fusion were achieved in both patients (gout arthropathy, n?=?1; posttraumatic arthritis, n?=?1) at an average of 6 weeks postoperatively. Our current indications, along with pearls and pitfalls with this technique, are reviewed. In select patients, this percutaneous DIP joint arthrodesis is advantageous in comparison with open fusion techniques. PMID:22131929

Ruchelsman, David E; Hazel, Antony; Mudgal, Chaitanya S

2010-12-01

158

Familial distal dysautonomia.  

PubMed Central

A patient is described who presented with painful feet on exercise. He had no evidence of peripheral vascular disease but did have anhidrosis and failure of vasodilatation in the hands and feet suggesting peripheral dysautonomia. Examination of his mother and a cousin and clinical histories of blood relatives suggested that his problem was a severe presentation of a familial distal dysautonomia. In other family members this was represented by dry hands and feet and variable vasomotor symptoms. This condition appeared to be autosomal dominant.

Robinson, B; Johnson, R; Abernethy, D; Holloway, L

1989-01-01

159

Distal radius fractures.  

PubMed

Distal radius fractures are a common injury, particularly in the elderly population. Severity of these fractures is directly related to the bone mineral density of the patient, and clinical results are dependent on this parameter as well. In terms of treatment, several options exist. Nonoperative management consists of closed treatment with casting. Operative treatment options include intrafocal pinning, nonbridging and bridging external fixation, arthroscopic-assisted external fixation, and various methods of open reduction internal fixation. When operative intervention is indicated, considerations include the characteristics of the fracture and the experience of the surgeon with the treatment modalities. PMID:19858984

Liporace, Frank A; Adams, Mark R; Capo, John T; Koval, Kenneth J

2009-01-01

160

Metal artifacts from titanium and steel screws in CT, 1.5T and 3T MR images of the tibial Pilon: a quantitative assessment in 3D  

PubMed Central

Radiographs are commonly used to assess articular reduction of the distal tibia (pilon) fractures postoperatively, but may reveal malreductions inaccurately. While magnetic resonance imaging (MRI) and computed tomography (CT) are potential three-dimensional (3D) alternatives they generate metal-related artifacts. This study aims to quantify the artifact size from orthopaedic screws using CT, 1.5T and 3T MRI data. Three screws were inserted into one intact human cadaver ankle specimen proximal to and along the distal articular surface, then CT, 1.5T and 3T MRI scanned. Four types of screws were investigated: titanium alloy (TA), stainless steel (SS) (Ø =3.5 mm), cannulated TA (CTA) and cannulated SS (CSS) (Ø =4.0 mm, Ø empty core =2.6 mm). 3D artifact models were reconstructed using adaptive thresholding. The artifact size was measured by calculating the perpendicular distance from the central screw axis to the boundary of the artifact in four anatomical directions with respect to the distal tibia. The artifact sizes (in the order of TA, SS, CTA and CSS) from CT were 2.0, 2.6, 1.6 and 2.0 mm; from 1.5T MRI they were 3.7, 10.9, 2.9, and 9 mm; and 3T MRI they were 4.4, 15.3, 3.8, and 11.6 mm respectively. Therefore, CT can be used as long as the screws are at a safe distance of about 2 mm from the articular surface. MRI can be used if the screws are at least 3 mm away from the articular surface except for SS and CSS. Artifacts from steel screws were too large thus obstructed the pilon from being visualised in MRI. Significant differences (P<0.05) were found in the size of artifacts between all imaging modalities, screw types and material types, except 1.5T versus 3T MRI for the SS screws (P=0.063). CTA screws near the joint surface can improve postoperative assessment in CT and MRI. MRI presents a favourable non-ionising alternative when using titanium hardware. Since these factors may influence the quality of postoperative assessment, potential improvements in operative techniques should be considered.

Radzi, Shairah; Cowin, Gary; Robinson, Mark; Pratap, Jit; Volp, Andrew; Schuetz, Michael A.

2014-01-01

161

Metal artifacts from titanium and steel screws in CT, 1.5T and 3T MR images of the tibial Pilon: a quantitative assessment in 3D.  

PubMed

Radiographs are commonly used to assess articular reduction of the distal tibia (pilon) fractures postoperatively, but may reveal malreductions inaccurately. While magnetic resonance imaging (MRI) and computed tomography (CT) are potential three-dimensional (3D) alternatives they generate metal-related artifacts. This study aims to quantify the artifact size from orthopaedic screws using CT, 1.5T and 3T MRI data. Three screws were inserted into one intact human cadaver ankle specimen proximal to and along the distal articular surface, then CT, 1.5T and 3T MRI scanned. Four types of screws were investigated: titanium alloy (TA), stainless steel (SS) (Ø =3.5 mm), cannulated TA (CTA) and cannulated SS (CSS) (Ø =4.0 mm, Ø empty core =2.6 mm). 3D artifact models were reconstructed using adaptive thresholding. The artifact size was measured by calculating the perpendicular distance from the central screw axis to the boundary of the artifact in four anatomical directions with respect to the distal tibia. The artifact sizes (in the order of TA, SS, CTA and CSS) from CT were 2.0, 2.6, 1.6 and 2.0 mm; from 1.5T MRI they were 3.7, 10.9, 2.9, and 9 mm; and 3T MRI they were 4.4, 15.3, 3.8, and 11.6 mm respectively. Therefore, CT can be used as long as the screws are at a safe distance of about 2 mm from the articular surface. MRI can be used if the screws are at least 3 mm away from the articular surface except for SS and CSS. Artifacts from steel screws were too large thus obstructed the pilon from being visualised in MRI. Significant differences (P<0.05) were found in the size of artifacts between all imaging modalities, screw types and material types, except 1.5T versus 3T MRI for the SS screws (P=0.063). CTA screws near the joint surface can improve postoperative assessment in CT and MRI. MRI presents a favourable non-ionising alternative when using titanium hardware. Since these factors may influence the quality of postoperative assessment, potential improvements in operative techniques should be considered. PMID:24914417

Radzi, Shairah; Cowin, Gary; Robinson, Mark; Pratap, Jit; Volp, Andrew; Schuetz, Michael A; Schmutz, Beat

2014-06-01

162

The Turn of the Screw: Optimal Design of an Archimedes Screw  

Microsoft Academic Search

The geometry of an Archimedes screw is governed by certain external parameters (its outer radius, length, and slope) and certain internal parameters (its inner radius, number of blades, and the pitch of the blades). The external parameters are usually determined by the location of the screw and how much water is to be lifted. The internal parameters, however, are free

Chris Rorres

2000-01-01

163

Use of the Interlock Fibered IDC Occlusion System in Clinical Practice.  

PubMed

The use of coils in embolotherapy has been extensively described. Many different types of coils are commercially available for use. In 2006, the Interlock Fibered IDC Occlusion System (Boston Scientific, Natick, MA) was introduced to clinical practice. In this article, embolotherapy with coils in general is discussed, and the use of the Interlock coils in particular is described in different clinical scenarios. PMID:21326487

Van Ha, Thuong G

2008-03-01

164

Interlocking directorates and the knowledge transfer of supermarket retail techniques from North America to Britain  

Microsoft Academic Search

This paper considers the importance of interlocking directorates in knowledge transfer within the retail sector. In doing so it provides a discussion of the types of knowledge and more especially the importance of tacit knowledge. Such ideas are set against a more detailed review of the changing perspectives on the role of interlocking directorships. These discussions serve as a conceptual

Gareth Shaw; Andrew Alexander

2006-01-01

165

Axial loading cross screw fixation for the Austin bunionectomy.  

PubMed

The Austin procedure has become a common method of osteotomy for the correction of hallux abductovalgus when indicated. The V-type configuration is intrinsically stable but not without complications. One complication encountered is rotation and/or displacement of the capital fragment. We present the use of an axial loading screw in conjunction with a dorsally placed compression screw. The benefit to this technique lies in the orientation of the axial loading screw, because it is directed to resist the ground reactive forces while also providing a second point of fixation in a crossing screw design. In a head-to-head biomechanical comparison, we tested single dorsal screw fixation versus double screw fixation, including both the dorsal and the axial loading screws in 10 metatarsal Sawbones(®) (Pacific Research Laboratories Inc, Vashon, WA). Five metatarsals received single dorsal screw fixation and five received the dorsal screw and the additional axial loading screw. The metatarsals were analyzed on an Instron compression device for comparison; 100% of the single screw fixation osteotomies failed with compression at an average peak load of 205 N. Four of five axial loading double screw fixation osteotomies did not fail. This finding suggests that the addition of an axial loading screw providing cross screw orientation significantly increases the stability of the Austin osteotomy, ultimately decreasing the likelihood of displacement encountered in the surgical repair of hallux abductovalgus. PMID:21621434

Rigby, Ryan B; Fallat, Lawrence M; Kish, John P

2011-01-01

166

Modified trajectory of c2 laminar screw - double bicortical purchase of the inferiorly crossing screw.  

PubMed

The crossing laminar screw fixation might be the most recently developed approach among various fixation techniques for C2. The new construct has stability comparable to transarticular or transpedicular screw fixation without risk of vertebral artery injury. Quantitative anatomical studies about C2 vertebra suggest significant variation in the thickness of C2 lamina as well as cross sectional area of junction of lamina and spinous process. We present an elderly patient who underwent an occipito-cervical stabilization incorporating crossed C2 laminar screw fixation. We preoperatively recognized that she had low profiles of C2 lamina, and thus made a modification of trajectory for the inferiorly crossing screw. We introduce a simple modification of crossing C2 laminar screw technique to improve stability in patients with low laminar profiles. PMID:19096618

Rhee, Woo-Tack; You, Seung-Hoon; Jang, Yeon-Gyu; Lee, Sang-Youl

2008-02-01

167

Temperature calculation for extruder screws with internal heat pipes  

NASA Astrophysics Data System (ADS)

One possibility of directly influencing the temperature profile in an extruder is by tempering the screw. This method is currently used in double-screw extrusion and in certain specialized applications in the field of single-screw extrusion. Significant possibilities of influencing the temperature have been shown, for example, while processing PVC on counterrotating double-screw extruders [1]. However, until now, it has not been possible to theoretically model this effect. This paper will thus introduce a mathematical model which describes the effect of internal screw tempering on the temperature gradient of the material in the extruder, allowing processes using tempered screws to be better designed and dimensioned.

Lakemeyer, C.; Schöppner, V.

2014-05-01

168

THE INTERLOCK STRUCTURE OF THE POLICY-PLANNING NETWORK AND THE RIGHT TURN IN U.S. STATE POLICY  

Microsoft Academic Search

This paper examines interlocks among the governing boards of 12 leading policy- planning organizations and changes in the structure of this network between 1973 and 2000. Methods of multidimensional scaling and hierarchical clustering are used to construct topographical maps of the pattern of interlocks among policy-planning groups and their change over time. In contrast to the findings on corporate interlocking

Val Burris

169

Apparatus to test insertion and removal torque of bone screws.  

PubMed

This paper describes affordable equipment for testing bone screw torque, corresponding to ASTM standard F543-00 for testing metallic medical bone screws. Correct testing of thin and long bone screws is essential due to screw failures during insertion and removal of the screws. Furthermore, insertion torque is an important factor in predicting fixation strength, screw pull-out force and effects of surface treatment of screws. The capability of the custom-built tester was determined using polytetrafluoroethylene and wood disc samples and bone screws. Bovine cortical bones allowed testing to the failure limit, i.e. the torque increased in long screws to the fracture limit. For 2.7 and 3.5 mm thick self-tapping cortical bone screws, the failure torques were 30-50 per cent higher than the minimum values required by the standard (1.0 and 2.3 N m respectively). The equipment provided reproducible results and fulfilled the ASTM standard very well. Preliminary testing with amorphous diamond coated bone screws showed good durability of the coating and on average 10-15 per cent lower torque values compared with uncoated screws. The equipment can be used to measure insertion and removal torques as described in the standard. Furthermore, it also allows testing of normal screws and bolts. PMID:14702987

Koistinen, A; Santavirta, S; Lappalainen, R

2003-01-01

170

Screw expander for light duty diesel engines  

NASA Technical Reports Server (NTRS)

Preliminary selection and sizing of a positive displacement screw compressor-expander subsystem for a light-duty adiabatic diesel engine; development of a mathematical model to describe overall efficiencies for the screw compressor and expander; simulation of operation to establish overall efficiency for a range of design parameters and at given engine operating points; simulation to establish potential net power output at light-duty diesel operating points; analytical determination of mass moments of inertia for the rotors and inertia of the compressor-expander subsystem; and preparation of engineering layout drawings of the compressor and expander are discussed. As a result of this work, it was concluded that the screw compressor and expander designed for light-duty diesel engine applications are viable alternatives to turbo-compound systems, with acceptable efficiencies for both units, and only a moderate effect on the transient response.

1983-01-01

171

Low energy high pressure miniature screw valve  

DOEpatents

A low energy high pressure screw valve having a valve body having an upper portion and a lower portion, said lower portion of said valve body defining an inlet flow passage and an outlet flow passage traversing said valve body to a valve seat, said upper portion of said valve body defining a cavity at said valve seat, a diaphragm restricting flow between said upper portion of said valve body and said lower portion, said diaphragm capable of engaging said valve seat to restrict fluid communication between said inlet passage and said outlet passage, a plunger within said cavity supporting said diaphragm, said plunger being capable of engaging said diaphragm with said valve seat at said inlet and outlet fluid passages, said plunger being in point contact with a drive screw having threads engaged with opposing threads within said upper portion of said valve body such engagement allowing motion of said drive screw within said valve body.

Fischer, Gary J. (Sandia Park, NM); Spletzer, Barry L. (Albuquerque, NM)

2006-12-12

172

Effect of screw diameter, insertion technique, and bone cement augmentation of pedicular screw fixation strength.  

PubMed

This study investigated (1) the effect of screw diameter and insertion technique in lumbar vertebrae, and insertion site in the sacrum, on the axial pullout force and transverse bending stiffness of pedicle screws, and (2) the effect of bone cement augmentation using polymethylmethacrylate (PMMA) and the biodegradable composite, poly(propylene glycol-fumarate) on axial pullout force and transverse bending stiffness of pedicle screws inserted into lumbar vertebrae. The axial pullout force and transverse bending stiffness of a 6.25-mm Steffee screw and a 6-mm Kluger screw did not differ significantly in vertebral bodies of similar equivalent bone mineral density. The axial pullout force of Schanz screws was significantly increased with a 1-mm increase in screw diameter. However, there was no significant increase in transverse bending stiffness. In the sacrum, an approach through the S1 facet produced significantly higher axial pullout forces and transverse bending stiffness than the approach described by Harrington and Dickson. PMMA and a biodegradable composite bone cement poly(propylene glycol-fumarate) both increased the axial pullout force. PMMA also increased the transverse bending stiffness. PMID:8222439

Wittenberg, R H; Lee, K S; Shea, M; White, A A; Hayes, W C

1993-11-01

173

Active interlock for the NSLS-II damping wiggler  

NASA Astrophysics Data System (ADS)

The NSLS-II is a 3rd generation light source with ultra-low beam emittance that is currently under construction at the Brookhaven National Laboratory. Because the power of the synchrotron radiation from the damping wiggler (DW) is about 64 kW, a slight mis-steer can result in severe damage to the vacuum chamber. To avoid such problems, an active interlock system is being considered. The system dumps the beam when it departs from the predefined safe window in the phase space. In this paper, we present simple geometric arguments from which we define the safe window on the basis of betatron amplitudes. This window can be applied to any DW around the ring. For the entrance of the wiggler, we obtained window of ?x=±8.4 mm, ?x'=±429 ?rad and ?y=±2.1 mm, ?y'=±449 ?rad.

Choi, J.; Willeke, F.

2012-07-01

174

Switchable reconfiguration of an interlocked DNA olympiadane nanostructure.  

PubMed

Interlocked DNA rings (catenanes) are interesting reconfigurable nanostructures. The synthesis of catenanes with more than two rings is, however, hampered, owing to low yields of these systems. We report a new method for the synthesis of catenanes with a controlled number of rings in satisfactory yields. Our approach is exemplified by the synthesis of a five-ring DNA catenane that exists in four different configurations. By the use of nucleic acids as "fuels" and "antifuels", the cyclic reconfiguration of the system across four states is demonstrated. One of the states, olympiadane, corresponds to the symbol of the Olympic Games. The five-ring catenane was implemented as a mechanical scaffold for the reconfiguration of Au NPs. The advantages of DNA catenanes over supramolecular catenanes include the possibility of generating highly populated defined states and the feasibility of tethering nanoobjects to the catenanes, which act as a mechanical scaffold to reconfigure the nanoobjects. PMID:24889855

Lu, Chun-Hua; Qi, Xiu-Juan; Cecconello, Alessandro; Jester, Stefan-Sven; Famulok, Michael; Willner, Itamar

2014-07-14

175

Group Distal Movement of Teeth using Micro-Screw-Implant Anchorage-A Case Report.  

PubMed

This case report describes a case of orthodontic tooth movement of a 29-year-old female patient utilizing maxillary posterior edentulous area. Micro-implants were placed at buccal edentulous spaces and inter-radicular space for retraction of entire maxillary dentition. An overjet reduction of 8mm and good posterior occlusion were achieved. PMID:24995260

Kalarickal, Biju

2014-05-01

176

Group Distal Movement of Teeth using Micro-Screw-Implant Anchorage-A Case Report  

PubMed Central

This case report describes a case of orthodontic tooth movement of a 29-year-old female patient utilizing maxillary posterior edentulous area. Micro-implants were placed at buccal edentulous spaces and inter-radicular space for retraction of entire maxillary dentition. An overjet reduction of 8mm and good posterior occlusion were achieved.

2014-01-01

177

Detection of phosphatidylethanol (PEth) in the blood of drivers in an alcohol ignition interlock program  

PubMed Central

Objective The rate of failed interlock blood alcohol concentration (BAC) tests is a strong predictor of recidivism post-interlock and a partial proxy for alcohol use. Alcohol biomarkers measured at the start of an interlock program are known to correlate well with rates of failed BAC tests over months of interlock use. This study evaluates two methods of measuring low blood levels of the biomarker PEth (phosphatidylethanol). PEth is a 100% alcohol specific biomarker and strongly intercorrelated with several independent indicators of drinking driving risk, including 8 other biomarkers, 3 psychometric assessments, and the rate of failed interlock BAC tests during many months of interlock use. Does a more sensitive method of measuring PEth at program entry detect drinking even among those who subsequently log no failed interlock tests? Methods In a sample of 281 driver blood samples, PEth was measured by both high-performance liquid chromatography (HPLC) and liquid chromatography tandem mass spectrometry (LCMSMS) in order to compare sensitivity and accuracy. The average rate of failed interlock BAC tests was the criterion measure for marker sensitivity. LCMSMS, calibrated to detect low levels of drinking as a possible measure of abstinence violation, was judged relative to the standard HPLC assay for PEth measured up to 4 µmol/L. Results The two methods showed a good quantitative relationship (r2>.86). LCMSMS detected positive PEth levels in samples that were below the limit of detection of the HPLC method. PEth measured by LCMSMS was positive for a higher proportion of DUI offenders who logged zero failed interlock BAC tests than were detected by HPLC. Conclusion Although HPLC is the widely used standard for measuring PEth in clinical alcoholism samples, the LCMSMS method, when calibrated to detect trace amounts of the major component of PEth, can detect abstinence levels of alcohol near zero intake and still correlate strongly with other indicators related to alcohol use and road safety.

Marques, Paul; Hansson, Therese; Isaksson, Anders; Walther, Lisa; Jones, Joseph; Lewis, Douglas; Jones, Mary

2011-01-01

178

Stiffness between different directions of transpedicular screws and vertebra  

Microsoft Academic Search

Objective. This study was undertaken to evaluate the variation in bone density within the vertebral body and to determine the biomechanical stiffness of the screw-bone interface for different superior-inferior transpedicular screw orientations in the vertebral body.Design. The stiffness of three directions of screw placement (upper, middle, and lower) were measured in two modes of loading (flexion and torsion). All screws

Shing-Sheng Wu; W. Thomas Edwards; Hansen A. Yuan

1998-01-01

179

Radiostrontium clearance and bone formation in response to simulated internal screw fixation  

SciTech Connect

Changes in radiostrontium clearance (SrC) and bone formation (tetracycline labeling) were observed in the femurs of skeletally mature dogs following the various operative steps involved in bone screw fixation. Drilling, but not periosteal stripping, produced a small but statistically significant increase in SrC and endosteal bone formation in the distal third of the bone. Strontium clearance values equivalent to those produced by drilling alone were recorded after screw fixation at low or high torque (5 versus 20 inch pounds), as well as by the insertion of loosely fitting stainless steel implants. Bone formation (equals the percentage tetracycline-labeled trabecular bone surfaces) was increased by 30% when SrC values exceeded 3.5 ml/100 g bone/min, and the relationship was linear when SrC values ranged between 1.0 and 7.0 ml/100 g bone/min. The changes in SrC and bone formation one-week after bone screw application are primarily those associated with a response to local trauma caused by drilling.

Daum, W.J.; Simmons, D.J.; Fenster, R.; Shively, R.A.

1987-06-01

180

Plasma processing for inducing bioactivity in stainless steel orthopaedic screws  

Microsoft Academic Search

The work presented in this paper is centred on applying plasma processing for inducing bioactivity (ability of a material to bond with bone) in otherwise bioinert stainless steel screws commonly used in orthopaedic surgery. As-received cortical stainless steel screws were hydroxylated using a patented two-step plasma process developed by the authors. The bioactivity of the screws thus processed was investigated

Sunil Kumar; Darren Simpson; Roger St. C. Smart

2007-01-01

181

Self-tapping screw fixation of the Austin osteotomy.  

PubMed

The authors present an alternative method of fixation for the Austin bunionectomy using the Richards self-tapping screw. A description of the screw and method of application is included. In more than 250 osteotomies fixated by this technique, no complications inherent to the self-tapping screw have been encountered. PMID:2319102

Klein, M S; Ognibene, F A; Erali, R P; Hendrix, C L

1990-01-01

182

A Novel Pedicle Screw with Mobile Connection: A Pilot Study  

PubMed Central

To prevent adjacent disc problems after spinal fusion, a pedicle screw with a mobile junction between the head and threaded shaft was newly developed. The threaded shaft of the screw has 10 degrees mobility in all directions, but its structure is to prevent abnormal translation and tilting. This screw was evaluated as follows: (1) endurance test: 106 times rotational stress was applied; (2) biological reactions: novel screws with a mobile head and conventional screws with a fixed head were inserted into the bilateral pedicles of the L3, L4, and L5 in two mini pigs with combination. Eight months after surgery, vertebral units with the screw rod constructs were collected. After CT scan, the soft and bony tissues around the screws were examined grossly and histologically. As a result, none of the screws broke during the endurance test stressing. The mean amount of abrasion wear was 0.0338?g. In the resected mini pig section, though zygapophyseal joints between fixed-head screws showed bony union, the amount of callus in the zygapophyseal joints connected with mobile-head screws was small, and joint space was confirmed by CT. No metalloses were noted around any of the screws. Novel screws were suggested to be highly durable and histologically safe.

Oshima, Masashi; Ajiro, Yasumitsu; Uei, Hiroshi

2014-01-01

183

Biomechanical evaluation of a new composite bioresorbable screw.  

PubMed

A new bioresorbable composite cannulated screw has been developed for small bone fracture fixation. The LG ("Little Grafter") screw is manufactured from Biosteon, which is a composite of poly L-lactic acid and hydroxyapatite. This study aimed to compare interfragmentary compression generated by this new screw with conventional metal screws commonly used in scaphoid fracture fixation. Four small metallic screws were compared with the LG screw, using a bone model produced from rigid polyurethane foam. The screws included the Acutrak, Asnis III, Herbert and Herbert-Whipple screws. The mean maximum compression forces for the LG screw, the Asnis and the Acutrak were comparable (LG 32.3 N, Asnis 32.8 N, Acutrak 38.3 N), whereas those using the Herbert and the Herbert-Whipple screw were significantly lower (Herbert 21.8 N, Herbert-Whipple 19.9 N). The bioresorbable LG screw has been shown to have good compressive properties compared to commonly used small bone fragment compression screws. PMID:16361004

Bailey, C A; Kuiper, J H; Kelly, C P

2006-04-01

184

Nylon screws make inexpensive coil forms  

NASA Technical Reports Server (NTRS)

Standard nylon screws act as coil form copper wire laid down in spiral thread. Completed coil may be bonded to printed-circuit board. However, it is impossible to tune coil by adjusting spacing between windings, technique sometimes used with air-core coils.

Aucoin, G.; Rosenthal, C.

1978-01-01

185

Computer simulation of screw dislocation in aluminum  

NASA Technical Reports Server (NTRS)

The atomic structure in a 110 screw dislocation core for aluminum is obtained by computer simulation. The lattice statics technique is employed since it entails no artificially imposed elastic boundary around the defect. The interatomic potential has no adjustable parameters and was derived from pseudopotential theory. The resulting atomic displacements were allowed to relax in all three dimensions.

Esterling, D. M.

1976-01-01

186

Improvements to the single screw extruder  

NASA Technical Reports Server (NTRS)

The extrusion on a single screw extruder is examined. The process is divided into several steps: the dosage of the materials to be conveyed; the modification of the shape of the feeding opening which influences the feeding process and consequently the throughput of the extruder; optimizing the shape of the feeding zone to meet the specific material requirements; and plasticizing and homogenizing.

Hiemenz, C.; Ziegmann, G.; Franzkoch, B.; Hoffmanns, W.; Michaeli, W.

1977-01-01

187

Improvements In Ball-Screw Linear Actuators  

NASA Technical Reports Server (NTRS)

Report describes modifications of design of type of ball-screw linear actuator driven by dc motor, with linear-displacement feedback via linear variable-differential transformer (LVDT). Actuators used to position spacecraft engines to direct thrust. Modifications directed toward ensuring reliable and predictable operation during planned 12-year cruise and interval of hard use at end of cruise.

Iskenderian, Theodore; Joffe, Benjamin; Summers, Robert

1996-01-01

188

Radiographic study of iliac screw passages  

PubMed Central

Background The optimal iliac screw path was determined to provide references for lumbosacral-pelvic reconstruction. Methods Radiographic data of 100 patients with normal pelvis were selected for this study. Four paths were designed. Paths A, B, and C were from the starting point of the crossing point of the chiotic line and posterior iliac crest (CLIC, located at 24.0 mm above the posterior superior iliac spine) to the upper edge of the acetabulum, anterior inferior iliac spine, and acetabulum center, respectively. Path D was from the starting point of the posterior superior iliac spine to the anterior inferior iliac spine. The lengths of the different paths of screw passage and bone plate thicknesses of two narrow places were measured and analyzed. Results Paths A, B, and D were approximately equal in length, but the thickness of the iliac plate in path A was significantly thicker than those in paths B and D. No significant difference was found between the iliac thickness of paths A and C, but the passage length of path A was significantly longer than that of path C. Conclusion Path A had the longest passage length and thickest iliac plate and could accommodate the relatively longest and thickest iliac screw. Thus, path A was the optimal iliac screw passage.

2014-01-01

189

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

2009-01-01

190

Failure of femoral head fixation: a cadaveric analysis of lag screw cut-out with the gamma locking nail and AO dynamic hip screw  

Microsoft Academic Search

The most commonly reported failure mode of sliding hip screws in published literature is cut-out of the lag screw. This study investigates the resistance to failure of the femoral head, with lag screws used in two types of sliding hip screws, the gamma locking nail (Howmedica) and the dynamic hip screw (DHS) (Synthes). The investigation consisted of biomechanical tests under

R. C. Haynes; R. G. Pöll; A. W. Miles; R. B. Weston

1997-01-01

191

MR imaging for early complications of transpedicular screw fixation.  

PubMed

This series comprises ten patients treated with transpedicular screw fixation, who suffered early postoperative problems such as radicular pain or motor weakness. Besides plain radiographs, all patients were also evaluated with MR imaging. Three patients were reoperated for either repositioning or removal of the screws. MR images, especially T1-weighted ones, were very helpful for visualizing the problem and verifying the positions of the screws. In cases of wide areas of signal void around the screws, the neighboring axial MR images at either side, which have fewer artifacts, gave more information about the screws and the vertebrae. PMID:10333155

Colak, A; Kutlay, M; Demircan, N; Seçer, H I; Kibici, K; Ba?ekim, C

1999-01-01

192

49 CFR 571.102 - Standard No. 102; Transmission shift position sequence, starter interlock, and transmission...  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Standard No. 102; Transmission shift position sequence, starter interlock, and transmission braking effect. 571.102 Section... § 571.102 Standard No. 102; Transmission shift position sequence,...

2013-10-01

193

Interlock recovery during the drying, calcination and vitrification phase of Am/Cm processing  

SciTech Connect

This document summarizes the results of five CIM5 [5-inch Cylindrical Induction Melter] runs designed to demonstrate power interlock recovery methods during the drying, calcination and vitrification phases of the Am/Cm melter cycle.

Snyder, T.K.

2000-01-20

194

D0 Central Tracking Solenoid Energization, Controls, Interlocks and Quench Protection Operating Procedures.  

National Technical Information Service (NTIS)

This procedure is used when it is necessary to operate the solenoid energization, controls, interlocks and quench detection system. Note that a separate procedure exists for operating the solenoid 'cryogenic' systems. Only D0 Control Room Operators or the...

R. Hance

1998-01-01

195

Global ice-sheet system interlocked by sea level  

NASA Astrophysics Data System (ADS)

Denton and Hughes (1983, Quaternary Research20, 125-144) postulated that sea level linked a global ice-sheet system with both terrestrial and grounded marine components during late Quaternary ice ages. Summer temperature changes near Northern Hemisphere melting margins initiated sea-level fluctuations that controlled marine components in both polar hemispheres. It was further proposed that variations of this ice-sheet system amplified and transmitted Milankovitch summer half-year insolation changes between 45 and 75°N into global climatic changes. New tests of this hypothesis implicate sea level as a major control of the areal extent of grounded portions of the Antarctic Ice Sheet, thus fitting the concept of a globally interlocked ice-sheet system. But recent atmospheric modeling results ( Manabe and Broccoli, 1985, Journal of Geophysical Research90, 2167-2190) suggest that factors other than areal changes of the grounded Antarctic Ice Sheet strongly influenced Southern Hemisphere climate and terminated the last ice age simultaneously in both polar hemispheres. Atmospheric carbon dioxide linked to high-latitude oceans is the most likely candidate ( Shackleton and Pisias, 1985, Atmospheric carbon dioxide, orbital forcing, and climate. In "The Carbon Cycle and Atmospheric CO 2: Natural Variations Archean to Present" (E. T. Sundquest and W. S. Broecker, Eds.), pp. 303-318. Geophysical Monograph 32, American Geophysical Union, Washington, D.C.), but another potential influence was high-frequency climatic oscillations (2500 yr). It is postulated that variations in atmospheric carbon dioxide acted through an Antarctic ice shelf linked to the grounded ice sheet to produce and terminate Southern Hemisphere ice-age climate. It is further postulated that Milankovitch summer insolation combined with a warm high-frequency oscillation caused marked recession of Northern Hemisphere ice-sheet melting margins and the North Atlantic polar front about 14,000 14C yr B.P. This permitted renewed formation of North Atlantic Deep Water, which could well have controlled atmospheric carbon dioxide ( W. S. Broecker, D. M. Peteet, and D. Rind, 1985, Nature ( London) 315, 21-26). Combined melting and consequent sea-level rise from the three warming factors initiated irreversible collapse of the interlocked global ice-sheet system, which was at its largest but most vulnerable configuration.

Denton, George H.; Hughes, Terence J.; Karlén, Wibjörn

1986-07-01

196

Surgical screw segmentation for mobile C-arm CT devices  

NASA Astrophysics Data System (ADS)

Calcaneal fractures are commonly treated by open reduction and internal fixation. An anatomical reconstruction of involved joints is mandatory to prevent cartilage damage and premature arthritis. In order to avoid intraarticular screw placements, the use of mobile C-arm CT devices is required. However, for analyzing the screw placement in detail, a time-consuming human-computer interaction is necessary to navigate through 3D images and therefore to view a single screw in detail. Established interaction procedures of repeatedly positioning and rotating sectional planes are inconvenient and impede the intraoperative assessment of the screw positioning. To simplify the interaction with 3D images, we propose an automatic screw segmentation that allows for an immediate selection of relevant sectional planes. Our algorithm consists of three major steps. At first, cylindrical characteristics are determined from local gradient structures with the help of RANSAC. In a second step, a DBScan clustering algorithm is applied to group similar cylinder characteristics. Each detected cluster represents a screw, whose determined location is then refined by a cylinder-to-image registration in a third step. Our evaluation with 309 screws in 50 images shows robust and precise results. The algorithm detected 98% (303) of the screws correctly. Thirteen clusters led to falsely identified screws. The mean distance error for the screw tip was 0.8 +/- 0.8 mm and for the screw head 1.2 +/- 1 mm. The mean orientation error was 1.4 +/- 1.2 degrees.

Görres, Joseph; Brehler, Michael; Franke, Jochen; Wolf, Ivo; Vetter, Sven Y.; Grützner, Paul A.; Meinzer, Hans-Peter; Nabers, Diana

2014-03-01

197

Distal biceps tendon injuries--current treatment options.  

PubMed

Three percent of all biceps tendon ruptures occur at the distal aspect, where the tendon inserts into the radial tuberosity. Distal bicep tendon ruptures typically occur in middle-aged males after an eccentric extension load is applied to the elbow. Patients usually complain of a sudden, sharp, and painful tearing sensation in the antecubital region, with a palpable defect. The biceps squeeze and hook tests are specific maneuvers by which to diagnose distal biceps ruptures on physical examination. Magnetic resonance imaging (MRI) or ultrasound maybe be helpful to distinguish between partial and complete tears. Anatomic studies suggest there are two distinct insertions for the short and long heads of the distal biceps. The short head may be a more powerful flexor, and the long head may be a more powerful supinator. Nonoperative treatment typically results in loss of flexion and supination strength and endurance. Early anatomic re-attachment is the goal. Surgical approaches include one- or two-incision techniques, and tendon fixation methods include the use of suture anchors, bone tunnels, an endobutton, or biotenodesis screws. Biomechanical studies have shown that endobuttons have higher load-to-failure strengths, compared to the other fixation methods. However, clinical studies have demonstrated that patients do well regardless of surgical approach or fixation method. Possible complications include nerve injuries, heterotopic ossification, postoperative fracture, tendon rerupture, complex regional pain syndrome, and wound infection. Partial ruptures are significantly less common and initially can be treated conservatively. Chronic tears are more difficult to treat because of possible tendon retraction and poor tissue quality. Tendon grafts using semitendinosus, fascia lata, hamstring, Achilles (calcaneal), or flexor carpi radialis have been successfully used for length restoration in these cases. PMID:20632985

Quach, Tony; Jazayeri, Reza; Sherman, Orrin H; Rosen, Jeffrey E

2010-01-01

198

Cost-Benefit Analysis of an Alcohol Ignition Interlock for Installation in all Newly Registered Vehicles  

Microsoft Academic Search

Objective: This study conducted a cost-benefit analysis of an alcohol ignition interlock device in preventing alcohol-related fatalities and serious injuries when installed in all newly registered vehicles in Australia.Methods: Benefit-cost ratios (BCRs) were calculated by comparing the benefits associated with the number of road injuries the interlock was predicted to save with the costs associated with installing the device in

Julie A. Lahausse; Brian N. Fildes

2009-01-01

199

Automatic Generation of Relay Logic for Interlocking System Based on Statecharts  

Microsoft Academic Search

Computer-based Interlocking System (CIS) is a kind of widely applied safety-critical system in current signaling industry. CIS always uses relay logic to describe interlocking safety logic. Normally, all logic is designed by experienced signaling engineer manually, this develop mode is low-efficient and expensive. This paper presents a new logic design model. In this new model, a component-based model is used

Chen Xiangxian; Huang hai; He Yulin

2010-01-01

200

Effectiveness of Ignition Interlocks for Preventing Alcohol-Impaired Driving and Alcohol-Related Crashes  

Microsoft Academic Search

A systematic review of the literature to assess the effectiveness of ignition interlocks for reducing alcohol-impaired driving and alcohol-related crashes was conducted for the Guide to Community Preventive Services (Community Guide). Because one of the primary research issues of interest—the degree to which the installation of interlocks in offenders' vehicles reduces alcohol-impaired driving in comparison to alternative sanctions (primarily license

Randy W. Elder; Robert Voas; Doug Beirness; Ruth A. Shults; David A. Sleet; James L. Nichols; Richard Compton

2011-01-01

201

Imaging of the Distal Airways  

PubMed Central

Imaging techniques of the lung continues to advance with improving ability to image the more distal airways. Two imaging techniques are reviewed, computerized tomography and magnetic resonance with hyperpolarized helium-3.

Tashkin, Donald P.; de Lange, Eduard E.

2009-01-01

202

Results of uncemented distal locked prosthesis in revision hip arthroplasty with proximal femoral bone loss: A retrospective study  

PubMed Central

Introduction: Management of bone loss is a challenge in revision total hip arthroplasty (THA). A retrospective review was performed to study the use of uncemented distal locked prosthesis in cases with proximal femoral bone loss. Materials and Methods: Uncemented stems with distal interlocking were used in 65 hips during revision THAs with 38 hips having Paprosky IIIB/IV defects between January 1998 and February 2004. There were 48 males and 17 females in the study with an average age of 53 years (range 30-80 years). Radiographic and clinical outcome evaluation using the Harris hip score (HHS) were performed. Results: An improvement in HHS (mean: 33 points) was observed at final followup (mean: 9 years). Regeneration of proximal bone stock was observed without signs of loosening or subsidence and none of the stems were revised. Three patients developed recurrent dislocation while one had a stem subsidence of 1cm following removal of interlocking bolts. Conclusion: Uncemented distal locked prosthesis provide adequate stability in revision THA, aiding the reconstruction of bony deficiencies while avoiding the disadvantages of fully porous or cemented implants.

Agarwala, Sanjay; Jhunjhunwala, Hari Ram; Pachore, Jawahir A; Joglekar, Siddharth B; Eachempati, Krishna Kiran

2013-01-01

203

Inertial interlock bonding: A new approach to sputtering target construction  

SciTech Connect

Inertial interlock bonding (IIB) was developed to provide a reliable low cost automated method for joining dissimilar metal plates at low bulk bonding temperatures for the production of sputtering targets. Joining dissimilar metals at elevated temperatures creates residual stress from the differential thermal expansion of the bimetallic plates. The IIB method of joining dissimilar metal plates alleviates the need to increase the bulk temperature of the metal plates during bonding and thereby significantly reduces the residual stress. In IIB, the heat generated by inertial friction between two dissimilar metal plates is used to simultaneously (1) soften an intercalated ring that is forged into a matching T groove and (2) melt a thin solder layer that wets the other plate creating a reliable solder bond. While finite element modeling of the process indicates that the surface temperatures during bonding approach 1000 deg. C, the bulk temperature for the assembly remains below 70 deg. C. In this way, the differential thermal residual stress remains low, while a reliable bimetallic joint is formed. Results for joining tantalum to copper alloy plates for sputtering target applications are provided.

Wickersham, C. E. Jr.; Workman, David [Cabot Corporation, 157 Concord Road, Billerica, Massachusetts 01821 (United States); Edision Welding Institute, 1250 Arthur E Adams Drive, Columbus, Ohio 43221 (United States)

2007-01-15

204

ACIS design compliance with principle accelerator safety interlock design requirements.  

SciTech Connect

Prior to and during the design of the APS's Access Control Interlock System (ACIS), an effort was made to insure that the design complied with the relevant DOE and ANL requirements as well as those set forth in other recognized documents then in circulation. A paragraph-by-paragraph listing of the requirements (in some cases, recommended practices) and the corresponding ACIS design features was compiled for use by the review committees then in place. This tabulation was incorporated in the APS Safety Analysis Document (SAD) as Appendix A. With the evolutionary changes that have occurred to the APS and to the documents referenced, some of the details of these compliances have evolved as well. It has been decided to maintain the SAD as a ''living'' document, editing it in close time proximity to the evolving APS. Since Appendix A depicted the ACIS's original design compliance to an also-evolving set of documents, it was decided to remove Appendix A but to retain it as a reference document. This LS Note now contains that set of original design compliances. As the APS and the ACIS continue to evolve, the changes made will be subject to internal review and approval and will always be subject to the requirements set forth by the DOE and ANL.

Knott, M.

2005-02-23

205

Addition of an anti-rotation screw to the dynamic hip screw for femoral neck fractures.  

PubMed

The authors investigated the use of an anti-rotation screw with the dynamic hip screw (DHS) during internal fixation of Garden I and II femoral neck fractures. Sixty-five patients with Garden I and II femoral neck fractures (mean age, 70 years) were treated with internal fixation at the authors' institution. In 31 patients, a 2-hole DHS was used alone (group 1), and in 34 patients, the DHS was combined with an anti-rotation screw placed in the cranial part of femoral head and neck (group 2). Patients' preinjury function and mental level were assessed using the Barthel index and the Abbreviated Mental test, respectively. The outcome measures included cost implications, operative time, and intraoperative radiation dose. The modified Harris Hip Score and a radiological assessment were performed at a mean of 11 months (range, 8-24 months) postoperatively. The use of the anti-rotation screw was associated with a longer operative time (mean, 44.54 minutes in group 1 vs 51.52 minutes in group 2; P<.0001) and more fluoroscopy screening (mean dose area product, 28.39 cGy/cm(2) in group 1 vs 44.33 cGy/cm(2) in group 2; P=.03). The additional cost of using an anti-rotation screw was £106 ($170) per case. No difference existed between the 2 groups with regard to radiological union, onset of avascular necrosis, and rate of revision surgeries. An anti-rotation screw, used with the dynamic hip screw, involves extra costs, prolongs operative time, and requires more intraoperative fluoroscopy screening but offers no advantages with regard to fracture union. PMID:23823042

Makki, Daoud; Mohamed, Ahmed M; Gadiyar, Rajeev; Patterson, Marc

2013-07-01

206

Sliding screw implants for extracapsular hip fractures.  

PubMed

Hip fractures are associated with significant mortality and morbidity for the patients, more dependent residual status, and increased socio-economic cost. Many hip-fracture patients experience severe functional impairment, and most never recover their pre-fracture level of function. Current research has sought to identify the most effective treatments to reduce the incidence of hip fractures, improve survival and quality of life, and minimize complications and disability. The treatment of these fractures in the elderly aims to return these people to their pre-fracture mobility and functional level. This article reviews the surgical treatment options for extracapsular hip fractures and discusses their associated advantages, disadvantages, and complications. Two types of implants are currently available: the dynamic hip screw (DHS), and the intramedullary hip nail with one or two sliding screws. In this review, no clear advantage of one implant over another for the treatment of extracapsular hip fractures was evident. Both the DHS and hip nails can be used successfully for the treatment of stable hip fractures; for unstable fractures and low subtrochanteric fractures, hip nails are preferred. Although hip nails are associated with limited exposure, lower blood loss and transfusion requirements, and shorter operative time, complications are more common with hip nails. Long-term survival and function are similar in the two approaches. Hip nails with two sliding screws do not seem to make the difference in clinical practice that is reported in biomechanical studies. PMID:23016784

Mavrogenis, Andreas F; Kouvidis, George; Stavropoulos, Nikolaos A; Stavrakakis, Loannis; Katonis, Pavlos; Papagelopoulos, Panayiotis J

2012-01-01

207

Factors affecting the pullout strength of cancellous bone screws.  

PubMed

Screws placed into cancellous bone in orthopedic surgical applications, such as fixation of fractures of the femoral neck or the lumbar spine, can be subjected to high loads. Screw pullout is a possibility, especially if low density osteoporotic bone is encountered. The overall goal of this study was to determine how screw thread geometry, tapping, and cannulation affect the holding power of screws in cancellous bone and determine whether current designs achieve maximum purchase strength. Twelve types of commercially available cannulated and noncannulated cancellous bone screws were tested for pullout strength in rigid unicellular polyurethane foams of apparent densities and shear strengths within the range reported for human cancellous bone. The experimentally derived pullout strength was compared to a predicted shear failure force of the internal threads formed in the polyurethane foam. Screws embedded in porous materials pullout by shearing the internal threads in the porous material. Experimental pullout force was highly correlated to the predicted shear failure force (slope = 1.05, R2 = 0.947) demonstrating that it is controlled by the major diameter of the screw, the length of engagement of the thread, the shear strength of the material into which the screw is embedded, and a thread shape factor (TSF) which accounts for screw thread depth and pitch. The average TSF for cannulated screws was 17 percent lower than that of noncannulated cancellous screws, and the pullout force was correspondingly less. Increasing the TSF, a result of decreasing thread pitch or increasing thread depth, increases screw purchase strength in porous materials. Tapping was found to reduce pullout force by an average of 8 percent compared with nontapped holes (p = 0.0001). Tapping in porous materials decreases screw pullout strength because the removal of material by the tap enlarges hole volume by an average of 27 percent, in effect decreasing the depth and shear area of the internal threads in the porous material. PMID:8872262

Chapman, J R; Harrington, R M; Lee, K M; Anderson, P A; Tencer, A F; Kowalski, D

1996-08-01

208

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

209

A biomechanical comparison of unilateral and bilateral String-of-Pearls™ locking plates in a canine distal humeral metaphyseal gap model.  

PubMed

Objective: To compare the in vitro biomechanical performance of two String-of-Pearls (SOP) plate constructs in a canine distal humeral metaphyseal gap model. Methods: Seven pairs of canine cadaveric humeri, including the elbow joints, were prepared. One group consisted of a unilateral medially placed SOP plate with bicortical screws (UNI). The second group consisted of bilateral caudo-medial and caudo-lateral SOP plates applied with monocortical screws (BI). A 2 cm ostectomy was performed immediately proximal to the supratrochlear foramen. Constructs were tested in torsion and axial compression. Results: The UNI constructs had significantly lower stiffness in torsion and axial compression than the BI group. However, UNI constructs had a significantly higher ultimate strength than BI constructs. All UNI constructs failed by bending of the transcondylar screw and SOP plate. All BI constructs failed by axial pullout of the distal most screws. Clinical significance: In stabilizing canine supracondylar humeral fractures as modeled here, both the UNI model and the BI model demonstrated biomechanical advantages. The incorporation of a transcondylar screw through the medial plate appears to be beneficial to construct strength. PMID:24763388

Hurt, R J; Syrcle, J A; Elder, S; McLaughlin, R

2014-05-19

210

Dual load path ball screw with rod end swivel  

NASA Technical Reports Server (NTRS)

A dual drive ball has a ball screw shaft coupled at one end to a gear train and coupled at the other end to a ball screw nut. The ball screw shaft and ball screw nut are connected through complementary helical grooves filled with ball bearing balls. The outer surface of the ball screw nut is plined and can be driven by a second gear train. An output tube is coupled at one end to the ball screw nut and at its opposite end has a connector portion with a groove on its inner surface. A rod end has a coupling member for coupling to a surface to be actuated and a shaft portion with a groobe on its outer surface. This shaft portion is received with in the outputtube portion and the corresponding grooves are coupled through the use of a plurality of ball bearing balls.

Wngett, Paul (Inventor)

2002-01-01

211

Screw-matrix method in dynamics of multibody systems  

Microsoft Academic Search

In the present paper the concept of screw in classical mechanics is expressed in matrix form, in order to formulate the dynamical\\u000a equations of the multibody systems. The mentioned method can retain the advantages of the screw theory and avoid the shortcomings\\u000a of the dual number notation. Combining the screw-matrix method with the tool of graph theory in Roberson\\/Wittenberg formalism.

Liu Yanzhu

1988-01-01

212

Clinical application of C2 laminar screw technique  

Microsoft Academic Search

C2 laminar screws have become an increasingly used alternative method to C2 pedicle screw fixation. However, the outcome of\\u000a this technique has not been thoroughly investigated. A total of 35 cases with upper cervical spinal instability undergoing\\u000a C2 laminar screw fixation were reviewed. All cases had symptoms of atlantoaxial instability, such as craniocervical junction\\u000a pain, and were fixed with the

Weihu Ma; Leling Feng; Rongming Xu; Xiaochen Liu; Alan H. Lee; Shaohua Sun; Liujun Zhao; Yong Hu; Guanyi Liu

2010-01-01

213

Simulation and analysis of resin flow in injection machine screw  

Microsoft Academic Search

A method with simulation and analysis of the resin flow in a screw is presented to ease the control of some problems that\\u000a may affect the efficiency and the quality of the product among existing screws in an injection machine. The physical model\\u000a of a screw is established to represent the stress, the strain, the relationship between velocity and stress,

Ling-feng Li; Samir Mekid

2008-01-01

214

Overview of Pedicle Screw-Based Posterior Dynamic Stabilization Systems  

Microsoft Academic Search

\\u000a Using pedicle screws and rods in the lumbar spine has been familiar to spine surgeons since the 1980s. Originally, these constructs\\u000a were used to stabilize the spine while bony incorporation of the fusion bone graft occurred. Now, there are many options for\\u000a devices that are all built upon this early pedicle screw concept. While the placement of the screws has

Richard D. Guyer; Donna D. Ohnmeiss; Kevin R. Strauss

215

Looking back, looking forward: a reexamination of Benjamin Wolstein's interlock and the emergence of intersubjectivity.  

PubMed

In this paper the author takes a close look at Benjamin Wolstein's chapter, 'Therapy', from his book, Countertransference, published in 1959. This chapter contains a discussion of what he refers to as the interlock between analyst and patient, or today what we might describe as transference/countertransference enactment. The author shows how Wolstein's concept of the interlock and its relation to the analyst's countertransference was radical and innovative for its time. Wolstein's notion of a transference/countertransference interlock, along with the seminal contributions of Ferenczi and some of the early interpersonal theorists, anticipates the complexities of a two-person psychology and the entanglement which can occur from the intermingling of unconscious processes of analyst and patient in the experiential field. The author highlights three main ideas. First, the author provides a brief review of enactment with an emphasis on the role of the analyst's participation as conceptualized by the various theoretical perspectives. An historical context is given for Wolstein's clinical theorizing. Second, the author explicates Wolstein's concept of the interlock, with particular attention to the processes involved which account for the complexities it presents. Third, the author examines the 'working through' process, including the emergence of intersubjectivity in the resolution of the interlock. The author shows throughout Wolstein's emphasis on the influence of the analyst's personal psychology, mutuality, and intersubjectivity, all of which anticipated the gradual interpersonalization of psychoanalysis across the various schools of thought. PMID:19580593

Bonovitz, Christopher

2009-06-01

216

Treatment of Femoral Shaft Fracture with an Interlocking Humeral Nail in Older Children and Adolescents  

PubMed Central

Purpose Rigid interlocking nailing for femoral shaft fracture is ideal for use in adolescents in terms of stability of the fracture and convenience for the patient. However, numerous authors have reported that rigid interlocking nailing has some limitations in this age group due to the risk of complications. We evaluated the results of intramedullary nailing for femoral shaft fractures with an interlocking humeral nail in older children and adolescents. Materials and Methods We retrospectively reviewed records of patients treated with an interlocking humeral nail. Radiographs were examined for proximal femoral change and evidence of osteonecrosis. Outcomes were assessed by major or minor complications that occurred after operative treatment. Results Twenty-four femoral shaft fractures in 23 patients were enrolled. The mean age at the time of operation was 12 years and 8 months and the mean follow-up period was 21 months. Bony union was achieved in all patients without any complications related to the procedure such as infection, nonunion, malalignment and limb length discrepancy. All fractures were clinically and radiographically united within an average eight weeks. No patients developed avascular necrosis of the femoral head and coxa valga. Conclusion Intramedullary nailing through the greater trochanter using a rigid interlocking humeral nail is effective and safe for the treatment of femoral shaft fractures in older children and adolescents.

Park, Hoon

2012-01-01

217

[Evaluation of surgical repair of distal biceps tendon ruptures].  

PubMed

PURPOSE OF THE STUDY To present the results of surgical repair of ruptures of the distal tendon of the biceps brachii muscle and thus show the adequacy of this treatment. MATERIAL Between 1987 and 2006, 19 patients had surgery for distal biceps tendon rupture. Only one side was affected in each patient. All patients were men between 28 and 69 years (average age, 47.5 years) at the time of injury (surgery). When the patients were evaluated at the end of 2007, 18 patients were included, because one died a year after surgery. METHODS The surgical repair always included a single-incision anatomical reattachment into the radial tuberosity. In 11 patients, a modified Mac Reynolds method with screw and washer fixation was used; in seven patients the insertion was fixed with Mitek anchors and, in one, it was sutured to the adjacent soft tissues. The average follow-up was 7 years (range, 1 to 20.5 years). The patients were evaluated for the cause of injury, their physical activity, age, dominance of the injured arm, surgical procedure and complications. RESULTS In 18 patients surgical repair was done early and, in one, at 16 days after injury. In all of them the tendon was detached from its site of insertion, but never torn. The intra-operative complications included, in one patient, bleeding owing to iatrogenic damage to a branch of the brachial artery, and difficult separation of the tendon due to its previous healed injury in another patient. Early post-operative complications included superficial skin necrosis in one patient and transient neurological deficit of the dorsal brand of the radial nerve and of the lateral cutaneous nerve of the forearm in two and one patient, respectively. The late complications were heterotropic ossification in three patients and screw migration in the one treated by the Mac Reynolds method. Excellent results were recorded in 11 patients (61 %), and good outcomes with a slight restriction of motion or muscle strength not limiting the patient's physical activities were in six (33.5 %) patients; only one patient (5.5 %) experienced pain on moderate exercise and had recurrent heterotropic ossification. Apart from this condition, there was no difference in the frequency of complications associated with the method used. DISCUSSION Only sparse information on distal biceps tendon ruptures has been available in the relevant Czech literature and, if so, only small groups with short follow-ups have been involved. Conservative treatment or the methods of non-anatomical reattachment have poor functional outcomes. Much better results are achieved by anatomical reattachment. Based on our experience with the Mac Reynolds technique, an anterior single-incision approach using fixation with Mitek anchors can be recommended. CONCLUSIONS Early surgical repair involving anatomical reattachment from the anterior singleincision approach with two Mitek anchors is recommended when a rupture of the distal tendon insertion of the biceps brachii is diagnosed. Key words: biceps radii muscle, biceps tendon injury, tendon fixation, bone screw and washer use. PMID:19268049

Behounek, J; Hrubina, M; Skoták, M; Krumpl, O; Zahálka, M; Dvorák, J; Fucík, M

2009-02-01

218

Electro-magnetic archimedean screw motor-generator  

US Patent & Trademark Office Database

An Archimedes' screw serves as a rotor, inducer, impeller, and/or driver with motor and/or generator configurations that surround the screw by attaching to an outer cylinder of the screw. The screw acts as the motor's rotor axis with attached permanent magnets and or frame and the stator is built around the auxiliary circumference of this rotor. The rotor may also house half the bearings and can be used for the movement of fluids and/or solids, for cavitation-less drive of water vehicles, or for the generation of electrical power when the fluids become the motive force to drive the unit.

2004-05-25

219

Complications of transpedicular screw fixation in the cervical spine.  

PubMed

Today, posterior stabilization of the cervical spine is most frequently performed by lateral mass screws or spinous process wiring. These techniques do not always provide sufficient stability, and anterior fusion procedures are added secondarily. Recently, transpedicular screw fixation of the cervical spine has been introduced to provide a one-stage stable posterior fixation. The aim of the present prospective study is to examine if cervical pedicle screw fixation can be done by low risk and to identify potential risk factors associated with this technique. All patients stabilized by cervical transpedicular screw fixation between 1999 and 2002 were included. Cervical disorders included multisegmental degenerative instability with cervical myelopathy in 16 patients, segmental instability caused by rheumatoid arthritis in three, trauma in five and instability caused by infection in two patients. In most cases additional decompression of the spinal cord and bone graft placement were performed. Pre-operative and post-operative CT-scans (2-mm cuts) and plain X-rays served to determine changes in alignment and the position of the screws. Clinical outcome was assessed in all cases. Ninety-four cervical pedicle screws were implanted in 26 patients, most frequently at the C3 (26 screws) and C4 levels (19 screws). Radiologically 66 screws (70%) were placed correctly (maximal breach 1 mm) whereas 20 screws (21%) were misplaced with reduction of mechanical strength, slight narrowing of the vertebral artery canal (<25%) or the lateral recess without compression of neural structures. However, these misplacements were asymptomatic in all cases. Another eight screws (9%) had a critical breach. Four of them showed a narrowing of the vertebral artery canal of more then 25%, in all cases without vascular problems. Three screws passed through the intervertebral foramen, causing temporary paresis in one case and a new sensory loss in another. In the latter patient revision surgery was performed. The screw was loosened and had to be corrected. The only statistically significant risk factor was the level of surgery: all critical breaches were seen from C3 to C5. Percutaneous application of the screws reduced the risk for misplacement, although this finding was not statistically significant. There was also a remarkable learning curve. Instrumentation with cervical transpedicular screws results in very stable fixation. However, with the use of new techniques like percutaneous screw application or computerized image guidance there remains a risk for damaging nerve roots or the vertebral artery. This technique should be reserved for highly selected patients with clear indications and to highly experienced spine surgeons. PMID:15912352

Kast, E; Mohr, K; Richter, H-P; Börm, W

2006-03-01

220

Screws, Propellers and Fans Based on a Mobius Strip  

NASA Technical Reports Server (NTRS)

A Mobius strip concept is intended for improving the working efficiency of propellers and screws. Applications involve cooling, boat propellers, mixing in appliance, blenders, and helicopters. Several Mobius shaped screws for the average size kitchen mixers have been made and tested. The tests have shown that the mixer with the Mobius shaped screw pair is most efficient, and saves more than 30% of the electric power by comparison with the standard. The created video film about these tests illustrates efficiency of Mobius shaped screws.

Seiner, John M.; Backley, Floyd D.; Gilinsky, Mikhail

1998-01-01

221

Abrasion of abutment screw coated with TiN  

PubMed Central

STATEMENT OF PROBLEM Screw loosening has been a common complication and still reported frequently. PURPOSE The purpose of this study was to evaluate abrasion of the implant fixture and TiN coated abutment screw after repeated delivery and removal with universal measuring microscope. MATERIAL AND METHODS Implant systems used for this study were Osstem and 3i. Seven pairs of implant fixtures, abutments and abutment screws for each system were selected and all the fixtures were perpendicularly mounted in liquid unsaturated polyesther with dental surveyor. After 20 times of repeated closing and opening test, the evaluation for the change of inner surface of implant and TiN-coated abutment screw, and weight loss were measured. Mann-Whitney test with SPSS statistical software for Window was applied to analyze the measurement of weight loss. RESULTS TiN-coated abutment screws of Osstem and 3i showed lesser loss of weight than non-coated those of Osstem and 3i (P < .05, Mann-Whitney test). CONCLUSION Conclusively, TiN coating of abutment screw showed better resistance to abrasion than titanium abutment screw. It was concluded that TiN coating of abutment screw would reduce the loss of preload with good abrasion resistance and low coefficient of friction, and help to maintain screw joint stability.

Jung, Seok-Won; Son, Mee-Kyoung; Chung, Chae-Heon

2009-01-01

222

Ipsilateral nonunions of the coracoid process and distal clavicle--a rare shoulder girdle fracture pattern.  

PubMed

Coracoid fractures are uncommon injuries, in isolation or in association with other osseoligamentous injuries about the shoulder girdle. We report a case of successful operative management of symptomatic ipsilateral nonunions of a type I coracoid base fracture and a lateral one-third clavicular fracture, which developed following nonoperative treatment of this exceedingly rare injury pattern. Following open distal clavicle excision and reduction of the coracoclavicular interval with screw fixation, radiographic union and excellent clinical outcome were achieved. This rare and potentially troublesome injury pattern is discussed, and the literature regarding ipsilateral coracoid and osseoligamentous injuries about the shoulder is reviewed. PMID:20345361

Ruchelsman, David E; Christoforou, Dimitrios; Rokito, Andrew S

2010-01-01

223

Subcoracoid dislocation of the distal end of the clavicle. A case report.  

PubMed

Subcoracoid dislocation of the outer end of the clavicle in association with an acromial fracture is a rare injury usually produced by high energy trauma that moves the clavicle posterior to the conjoined tendon and inferior to the coracoid process. To restore the acromioclavicular joint, open reduction is needed. After the reduction is accomplished, the clavicle has to be stabilized with a coracoclavicular screw. The acromial fracture can be reduced and held with nonabsorbable sutures placed through the bone. To avoid osteolysis of the distal end of the clavicle and to be able to repair the torn ligaments, treatment should not be delayed. PMID:9553543

Torrens, C; Mestre, C; Pérez, P; Marin, M

1998-03-01

224

Mixing effects of constituting elements of mixing screws in single and twin screw extruders  

Microsoft Academic Search

In extrusion, mixing of solids and melts has always been problematic, leading to diverse models describing the melting process. It is found that for foods based on cereals, only a few are valid, due to the simultaneous presence of water and high viscous non-Newtonian material. Mixing trials are summarised for single and twin screw extruders, with particulate solids of different

D. J. van Zuilichem; E. Kuiper; W. Stolp; T. Jager

1999-01-01

225

Transforaminal lumbar interbody fusion using unilateral pedicle screws and a translaminar screw  

PubMed Central

Lumbar spinal fusion is advancing with minimally invasive techniques, bone graft alternatives, and new implants. This has resulted in significant reductions of operative time, duration of hospitalization, and higher success in fusion rates. However, costs have increased as many new technologies are expensive. This study was carried out to investigate the clinical outcomes and fusion rates of a low implant load construct of unilateral pedicle screws and a translaminar screw in transforaminal lumbar interbody fusion (TLIF) which reduced the cost of the posterior implants by almost 50%. Nineteen consecutive patients who underwent single level TLIF with this construct were included in the study. Sixteen patients had a TLIF allograft interbody spacer placed, while in three a polyetheretherketone (PEEK) cage was used. Follow-up ranged from 15 to 54 months with a mean of 32 months. A clinical and radiographic evaluation was carried out preoperatively and at multiple time points following surgery. An overall improvement in Oswestry scores and visual analogue scales for leg and back pain (VAS) was observed. Three patients underwent revision surgery due to recurrence of back pain. All patients showed radiographic evidence of fusion from 9 to 26 months (mean 19) following surgery. This study suggests that unilateral pedicle screws and a contralateral translaminar screw are a cheaper and viable option for single level lumbar fusion.

Lee, Sandra; Vaidya, Rahul

2008-01-01

226

Postfusion pullout strength comparison of a novel pedicle screw with classical pedicle screws on synthetic foams.  

PubMed

Pullout is a very common failure mode on the use of pedicle screws. Numerous studies were completed to increase the pullout strength of pedicle screws especially for osteoporotic bones. In this study, a previously designed pedicle screw type was tested before and after fusion condition. Synthetic polyurethane foams were used in all tests. Three different grades of foams were used in tests to simulate severely osteoporotic, osteoporotic, and healthy bones. Test blocks were produced and characterized in our clinical biomechanics laboratory. Foaming of polyurethane was accepted as fusion process (bone in growth). Pedicle screw including radial holes (new design) was tested both before and after the fusion. It also exhibited remarkably higher pullout strength after fusion than before fusion and most of other alternatives stated in the literature. In total, 70% higher pullout strength was achieved with new design after fusion. On the other hand, new design did not dominate other alternatives when comparison was carried out on severely osteoporotic and healthy bones. To the knowledge of the authors, this is the first study investigating the postfusion properties on synthetic foams. PMID:23513982

Arslan, Arslan K; Demir, Teyfik; Ormeci, Mehmet F; Camu?cu, Necip; Türeyen, Kudret

2013-02-01

227

Arc Detection and Interlock Module for the PEP-II Low Level RF System  

NASA Astrophysics Data System (ADS)

A new arc detection and interlock generating module for the SLAC PEP-II low-level RF VXI-based system has been developed. The system is required to turn off the RF high voltage power supply in the event of arcing in the cavity windows, klystron window, and circulator. Infrared photodiodes receive arc signals through radiation resistant optical fibers. Optical emitters are paired with the detectors to allow continuity and attenuation monitoring of the optical fiber cable. Gain and bandwidth are selectable for each channel to allow tailoring response. The module also responds to interlock requests from other modules in the VXI system and communicates with the industrial controller responsible for much of the low-level RF system's interlock functionality.

Tighe, R.

1997-05-01

228

Programmable controllers replace relays in MFTF-B personnel-safety interlocks  

SciTech Connect

This paper describes a new approach for implementing personnel safety interlocks logic using industrial-type programmable controllers. The logic for all personnel safety interlocks except those totally internal to a subsystem is implemented in two non-redundant controllers. A high degree of fail-safe reliability is achieved by augmenting the protective features intrinsic to each controller with those provided by a small amount of external support hardware. The controllers are interfaced to the host computer system via fiber optic data links to enable display of interlock and overall system status on the control room graphic displays. When fully implemented, the controllers will perform the equivalent of over 2000 discreet relay functions.

Branum, J.D.

1981-10-20

229

Magnesium alloys as a biomaterial for degradable craniofacial screws.  

PubMed

Recently, magnesium (Mg) alloys have received significant attention as potential biomaterials for degradable implants, and this study was directed at evaluating the suitability of Mg for craniofacial bone screws. The objective was to implant screws fabricated from commercially available pure Mg and alloy AZ31 in vivo in a rabbit mandible. First, Mg and AZ31 screws were compared to stainless steel screws in an in vitro pull-out test and determined to have a similar holding strength (?40N). A finite-element model of the screw was created using the pull-out test data, and this model can be used for future Mg alloy screw design. Then, Mg and AZ31 screws were implanted for 4, 8 and 12weeks, with two controls of an osteotomy site (hole) with no implant and a stainless steel screw implanted for 12weeks. Microcomputed tomography was used to assess bone remodeling and Mg/AZ31 degradation, both visually and qualitatively through volume fraction measurements for all time points. Histological analysis was also completed for the Mg and AZ31 at 12weeks. The results showed that craniofacial bone remodeling occurred around both Mg and AZ31 screws. Pure Mg had a different degradation profile than AZ31; however, bone growth occurred around both screw types. The degradation rate of both Mg and AZ31 screws in the bone marrow space and the muscle were faster than in the cortical bone space at 12weeks. Furthermore, it was shown that by alloying Mg, the degradation profile could be changed. These results indicate the promise of using Mg alloys for craniofacial applications. PMID:24384125

Henderson, Sarah E; Verdelis, Konstantinos; Maiti, Spandan; Pal, Siladitya; Chung, William L; Chou, Da-Tren; Kumta, Prashant N; Almarza, Alejandro J

2014-05-01

230

Joining mechanism with stem tension and interlocked compression ring  

DOEpatents

A stem (34) extends from a second part (30) through a hole (28) in a first part (22). A groove (38) around the stem provides a non-threaded contact surface (42) for a ring element (44) around the stem. The ring element exerts an inward force against the non-threaded contact surface at an angle that creates axial tension (T) in the stem, pulling the second part against the first part. The ring element is formed of a material that shrinks relative to the stem by sintering. The ring element may include a split collet (44C) that fits partly into the groove, and a compression ring (44E) around the collet. The non-threaded contact surface and a mating distal surface (48) of the ring element may have conic geometries (64). After shrinkage, the ring element is locked onto the stem.

James, Allister W.; Morrison, Jay A.

2012-09-04

231

A unique non-catenane interlocked self-assembled supramolecular architecture and its photophysical properties  

PubMed Central

A novel, interlocked, self-assembled (M2L2)2 molecular architecture (3) was constructed from arene-Ru acceptor 1 and 1,4-di(pyridine-4-yl)buta-1,3-diyne donor 2. Two M2L2 units, with cavities of ~7.21 Å, spontaneously interlock with one unit encapsulating a twin in a non-catenane fashion. The dimeric host-guest complex thus formed is unique among two dimensional self-assemblies and is stabilized by ?-? interactions between the M2L2 units.

Vajpayee, Vaishali; Song, Young Ho; Cook, Timothy R.; Kim, Hyunuk; Lee, Youngil; Stang, Peter J.; Chi, Ki-Whan

2011-01-01

232

Arthroscopic meniscal repair with an absorbable screw: results and surgical technique  

Microsoft Academic Search

The results of a new method for arthroscopic all-inside meniscus repair using a biodegradable cannulated screw (Clearfix meniscal screw) were assessed in a medium-term follow-up prospective study. The Clearfix meniscal screw system consists of delivery cannulae, screw driver, and screw implants. After tear debridement, a screw is located on the driver and passed through the cannula to the insertion site,

Michael E. Hantes; Elias S. Kotsovolos; Dimitrios S. Mastrokalos; Joerg Ammenwerth; Hans H. Paessler

2005-01-01

233

Surgical Treatment for Unstable Distal Clavicle Fracture with Micromovable and Anatomical Acromioclavicular Plate  

PubMed Central

Between 2006 and 2009, 18 patients of distal clavicle fracture were treated with micro-movable and anatomical acromioclavicular plate (MAAP) in our department. According to the Neer's classification, all cases were unstable with type IIA (12 cases) and type IIB (6 cases). Functional outcome was evaluated using the Karlsson's criteria. The mean follow-up was 18 months (range, 12-36months). No postoperative plate screws complication was observed. Osseous union could be achieved at a mean time of 12 weeks after operation in 18 patients (range, 8 -16 weeks). According to Karlsson's criteria, radiographic appearances and postoperative shoulder functional recovery revealed a good and excellent rate in these cases. We conclude that surgical treatment using MAAP seems to be a good option for unstable type II fractures of the distal clavicle. This technique allows for reliable fixation with early functional exercises and functional recovery.

Liu, Qingjun; Miao, Jianyun; Lin, Bin; Lian, Kejian

2012-01-01

234

Management of extra-articular fractures of the distal tibia: intramedullary nailing versus plate fixation.  

PubMed

Intramedullary nailing and plate fixation represent two viable approaches to internal fixation of extra-articular fractures of the distal tibia. Although both techniques have demonstrated success in maintaining reduction and promoting stable union, they possess distinct advantages and disadvantages that require careful consideration during surgical planning. Differences in soft-tissue health and construct stability must be considered when choosing between intramedullary nailing and plating of the distal tibia. Recent advances in intramedullary nail design and plate-and-screw fixation systems have further increased the options for management of these fractures. Current evidence supports careful consideration of the risk of soft-tissue complications, residual knee pain, and fracture malalignment in the context of patient and injury characteristics in the selection of the optimal method of fixation. PMID:23118133

Casstevens, Chris; Le, Toan; Archdeacon, Michael T; Wyrick, John D

2012-11-01

235

Thoracic pedicle screw fixation for spinal deformity.  

PubMed

Techniques to improve segmental fixation have advanced the ability to correct complex spinal deformity. The purpose of instrumentation is to correct spinal deformity or to stabilize the spine to enhance the long-term biological fusion. The ultimate goal of spinal deformity surgery is the creation of a stable, balanced, pain-free spine centered over the pelvis in the coronal and sagittal planes. The minimum number of segments should be fused. These concepts remain challenging in the setting of deformity and instability. Successful results can be obtained if the surgeon understands the technology available, its capabilities, biological limitations, and the desired solution. The authors prefer to use thoracic pedicle screws when treating patients with spinal deformity because they provide greater corrective forces for realignment. This allows shorter-segment constructs and the possibility of true derotation in correction. In this article the authors focus on the use of thoracic transpedicular screw fixation in the management of complex spinal disorders and deformity. PMID:15766224

Rosner, Michael K; Polly, David W; Kuklo, Timothy R; Ondra, Stephen L

2003-01-15

236

Screw dislocations in GaN  

SciTech Connect

GaN has received much attention over the past few years because of several new applications, including light emitting diodes, blue laser diodes and high-power microwave transistors. One of the biggest problems is a high density of structural defects, mostly dislocations, due to a lack of a suitable lattice-matched substrate since bulk GaN is difficult to grow in large sizes. Transmission Electron Microscopy (TEM) has been applied to study defects in plan-view and cross-sections on samples prepared by conventional techniques such as mechanical thinning and precision ion milling. The density of dislocations close to the sample surface of a 1 mm-thick HVPE sample was in the range of 3x109 cm-2. All three types of dislocations were present in these samples, and almost 50 percent were screw dislocations. Our studies suggest that the core structure of screw dislocations in the same material might differ when the material is grown by different methods.

Liliental-Weber, Zuzanna; Jasinski, Jacek B.; Washburn, Jack; O'Keefe, Michael A.

2002-02-15

237

[The value of miniature compression screws in maxillofacial surgery].  

PubMed

According to the well-known principle of compression, a new kind of screw has been developed. It is a development of the miniaturized Michelet-Champy osteosynthesis device which we have used for the last 10 years in maxillofacial surgery. These traction-screws were initially elaborated for rigid stabilization after sagittal ramus osteotomies such as Obwegeser-Dal Pont. Usually, three screws are inserted at each side, via a transjugal approach. It is then possible to remove the intermaxillary fixation device at the end of the surgical procedure. However, these screws are also useful in other cases: for other kinds of mandibular osteotomies (visor osteotomy for instance), in traumatology (oblique mandibular or condylar fractures) or for fixation of onlay bone grafts on the facial structures. When iliac bone grafts, which are essentially cancellous bone are used, it is possible to use a small metallic ring to avoid penetration of the head of the screw into the graft. The screws can be inserted by a cutaneous punctiform incision when it is impossible to pass the screwdriver through the buccal incision. In all cases, this material is particularly easy to insert, allows good fixation, permits a solid interosseous compression, and is particularly well tolerated. The main drawback is the difficulty of choosing the right length of the screws because only two lengths are available at the present time. Despite this problem, these mini traction-screws seem to be useful for maxillofacial surgeons. PMID:2470321

Boutault, F; Cadenat, H; Poirot, A; Bodin, H

1989-01-01

238

Accuracy of Pedicle Screw Placement in Thoracic Spine Fractures  

Microsoft Academic Search

Background and Purpose: Transpedicular instrumentation in the thoracic spine is technically difficult because of small pedicle diameters. There are not many studies assessing in vivo accuracy, complications, and the revision rate of transpedicular screws in the thoracic spine. In this retrospective study 278 thoracic pedicle screws of 43 patients were assessed using a scoring system and postoperative computed tomography (CT)

Marty Zdichavsky; Michael Blauth; Christian Knop; Joachim Lotz; Christian Krettek; Leonard Bastian

2004-01-01

239

Axial Loading Cross Screw Fixation for the Austin Bunionectomy  

Microsoft Academic Search

The Austin procedure has become a common method of osteotomy for the correction of hallux abductovalgus when indicated. The V-type configuration is intrinsically stable but not without complications. One complication encountered is rotation and\\/or displacement of the capital fragment. We present the use of an axial loading screw in conjunction with a dorsally placed compression screw. The benefit to this

Ryan B. Rigby; Lawrence M. Fallat; John P. Kish

2011-01-01

240

Biceps tenodesis with interference screw: cyclic testing of different techniques.  

PubMed

Different surgical techniques exist for biceps tenodesis. The most secure fixation technique is with interference screws. The purpose of the study was to compare the biomechanical performance of three different interference screw biceps tenodesis fixation methods, which involve different tunnel preparation methods. Using a sheep shoulder model and metal interference screws, a bone wedge technique was compared to serial tunnel dilation and a control group. After a preload, all repairs were cyclically loaded (20-60 N) for 100 cycles followed by destructive testing. Biceps tenodesis using an interference screw--bone wedge technique showed statistically lower cyclic displacement (8.1 ± 6.4 mm) than serial dilatation with an interference screw (21.3 ± 8.4 mm) or interference screw fixation alone (18.3 ± 8.3 mm) (P = 0.02). There were no statistically significant differences in ultimate failure strength for any of the interference screw biceps tenodesis techniques tested. The tunnel preparation method chosen for interference screw fixed biceps tenodesis can have a positive effect on tenodesis performance. Using the bone wedge technique may allow a more rapid rehabilitation program applicable for the traumatic biceps tendon rupture seen in young, athletic patients with high demands. PMID:20549186

Hapa, Onur; Günay, Cüneyd; Kömürcü, Erkam; Cak?c?, Hüsamettin; Bozda?, Ergun

2010-12-01

241

Use of the cannulated bone screw in rearfoot surgery.  

PubMed

There are many types of rigid internal fixation devices available for podiatric surgery. The cannulated screw system is an easy and effective way to decrease surgical time. These screws are being used with great success for several rearfoot procedures, such as the triple arthrodesis, Dwyer calcaneal osteotomy, and posterior malleolar ankle fractures. PMID:2507621

Chieppa, W A; Sydnor, K H; Walter, J H

1989-01-01

242

Continuous expression of slurry in a screw press  

Microsoft Academic Search

An approximate method is described for predicting the steadystate performance of a screw press for the continuous expression of a slurry, with the worm channel being modified as the path between two flat plates. Screw expression of a slurry involves two mechanisms of dewatering which, for a batch operation, can be analyzed by the variable-pressure, variable-rate theory of filtration and

M. Shirato; N. Hayashi; M. Iwata; T. Murase; Y. Ogawa

1985-01-01

243

Antibiotic cement screw for postoperative infection after gamma nailing.  

PubMed

Few articles describe the management of postoperative infection occurring after the use of an intramedullary nail in the treatment of femoral intertrochanteric fractures. Implant removal is frequently selected for postoperative infection control, especially in chronic cases. However, removal of the intramedullary nail causes a high rate of femoral neck fractures, challenging surgeons to prevent such fractures with few guidelines for how this can be done. This article presents 2 cases of postoperative infection following intramedullary nail implant in elderly women. After removal of the infected implant and meticulous debridement, an antibiotic cement screw (a cannulated screw enveloped with antibiotic-impregnated bone cement) was inserted from the lag screw hole into the femoral head. At the latest follow-up (mean, 18 months postoperatively), neither femoral neck fracture nor infection had occurred in either patient. The antibiotic cement screw is expected to provide stability and prevent fracture at the femoral neck region, and its more intimate contact with the medullary canal allows a higher concentration of local antibiotics than intravenous application. The antibiotic cement screw is recommended especially for infection after gamma nailing. We also introduce a simple, reproducible method for constructing an antibiotic cement screw large enough to fit the lag screw hole using bone cement, cannulated screw, antibiotics, and a chest tube. PMID:19708621

Noda, Mitsuaki; Saegusa, Yasuhiro; Takakura, Yoshiyuki; Kuroda, Ryosuke; Doita, Minoru

2009-08-01

244

Screw Gluing Kerto-LVL Structures with Polyurethane.  

National Technical Information Service (NTIS)

The objective was to find out the applicability of screw-pressing technique and to determine factors affecting the strength and quality of glue line in screw-pressed Laminated Veneer Lumber (LVL) elements purposed to structural use. The production of thes...

M. Kairi E. Kaloinen S. Koponen T. Nokelainen M. Fonselius A. Kevarinmaeki

1999-01-01

245

Anatomic considerations of costotransverse screw placement in the thoracic spine  

Microsoft Academic Search

BACKGROUNDNumerous techniques have been reported to restore spinal stability and to correct spinal deformities, including rods with wires\\/hooks, and rods or plates with pedicular screws. It was thought that posterior fixation of the thoracic spine through the costotransverse joint may be another alternative.METHODSNine cadavers were obtained for study of screw fixation of the costotransverse joint for posterior thoracic instrumentation. The

Rongming Xu; Nabil A Ebraheim; Yiangjia Ou; Martin Skie; Richard A Yeasting

2000-01-01

246

A shape-persistent quadruply interlocked giant cage catenane with two distinct pores in the solid state.  

PubMed

Discrete interlocked three-dimensional structures are synthetic targets that are sometimes difficult to obtain with "classical" synthetic approaches, and dynamic covalent chemistry has been shown to be a useful method to form such interlocked structures as thermodynamically stable products. Although interlocked and defined hollow structures are found in nature, for example, in some viruses, similar structures have rarely been synthesized on a molecular level. Shape-persistent interlocked organic cage compounds with dimensions in the nanometer regime are now accessible in high yields during crystallization through the formation of 96?covalent bonds. The interlocked molecules form an unprecedented porous material with intrinsic and extrinsic pores both in the micropore and mesopore regime. PMID:24706547

Zhang, Gang; Presly, Oliver; White, Fraser; Oppel, Iris M; Mastalerz, Michael

2014-05-12

247

Distal intramural spread of rectal carcinomas  

Microsoft Academic Search

Forty-three consecutive specimens of resected rectal carcinomas, 16 abdominoperineal and 27 anterior resections, were examined\\u000a for distal intramural spread. Thirty-four of the resections were considered curative and nine palliative. Eighteen carcinomas\\u000a (42 percent) showed no distal spread, and 14 (33 percent) showed very limited distal spread (0–5 mm). In the remaining cases,\\u000a 11 (25 percent) had distal spread of more

Per M. Madsen; John Christiansen

1986-01-01

248

Distal myopathy of Gowers: a reappraisal.  

PubMed

This article argues against the general idea that the patient described by Gowers as distal myopathy in 1902 may have suffered from myotonic dystrophy. A case of distal myopathy with markedly atrophic sternocleidomastoids is presented. Patients of distal myopathy with absence of sternocleidomastoids, sometimes accompanied by facial weakness, are recorded in the literature. All these cases are sporadic and may be called distal myopathy of Gowers, which is different from Welander's cases. PMID:6468454

Furukawa, T; Odajima, N; Watabiki, S; Tsukagoshi, H

1984-01-01

249

A simple model of throughput calculation for single screw  

NASA Astrophysics Data System (ADS)

To be able to predict the throughput of a single-screw extruder or the metering time of an injection moulding machine for a given screw geometry, set of processing conditions and polymeric material is important both for practical and designing purposes. Our simple model show that the screw geometry is the most important parameter, followed by polymer rheology and processing conditions. Melting properties and length seem to intervene to a lesser extent. The calculations hinges on the idea of viewing the entire screw as a pump, conveying a solid and a molten fraction. The evolution of the solid fraction is the essence of the plastication process, but under particular circumstances, its influence on the throughput is nil. This allows us to get a very good estimate on the throughput and pressure development along the screw. Our calculations are compared to different sets of experiments available from the literature. We have consistent agreement both in throughput and pressure with published data.

Béreaux, Yves; Charmeau, Jean-Yves; Moguedet, Maël

2007-04-01

250

Triplane fracture of the distal radius.  

PubMed

We report the case of a 14-year-old boy who sustained a displaced triplane fracture of the distal radius. This was treated with closed reduction and application of a cast with good clinical and radiological results. We discuss (for the first time) the reasons for the rarity of this fracture at the distal radius compared to the distal tibia. PMID:24765336

Pearce, Christopher; Chung, Raymond

2011-07-01

251

Fractures of the distal radius and ulna  

Microsoft Academic Search

Associated fractures of the distal ulnar metaphysis were present in 19 of 320 distal radial fractures requiring either closed manipulation or surgical treatment over a 2-year period. Four morphological patterns of ulnar fracture were encountered, the commonest being the type 1 simple extra-articular fracture of the distal end of ulna with minimal comminution (eight out of 19). 15 patients were

A. Biyani; A. J. M. Simison; L. Klenerman

1995-01-01

252

Lateral Movement of Screw Dislocations During Homoepitaxial Growth and Devices Yielded Therefrom Free of the Detrimental Effects of Screw Dislocations  

NASA Technical Reports Server (NTRS)

The present invention is related to a method that enables and improves wide bandgap homoepitaxial layers to be grown on axis single crystal substrates, particularly SiC. The lateral positions of the screw dislocations in epitaxial layers are predetermined instead of random, which allows devices to be reproducibly patterned to avoid performance degrading crystal defects normally created by screw dislocations.

Neudeck, Philip G. (Inventor); Powell, J. Anthony (Inventor)

2004-01-01

253

Use of screws and cement in primary TKA with up to 20 years follow-up.  

PubMed

The purpose of this study was to investigate screws and cement for large tibial bone defects during primary TKA. Of 14,686 consecutive primary TKAs performed between December 1988 and February 2010, 256 received screws and cement for tibial defects. Cox regression was used for the analysis. 20-year survival probability was 0.9897 (screws) and 0.9339 (no screws) (P = .4225 log-rank). Tibial bone condition was significantly worse in knees receiving screws (P < .0001) with 73.0% having defects in the screws group and 3.4% (P < .0001) for non-screws. Radiolucency appeared in 13.7% (screws) and 6.4% (no screws) postoperatively. Screws were $137 each, wedges $910 to $2240. Knees with tibial defects and screws performed similarly if not better than knees without defects at substantially lower cost than alternatives. PMID:24456788

Berend, Michael E; Ritter, Merrill A; Keating, E Michael; Jackson, Michael D; Davis, Kenneth E

2014-06-01

254

Homodyne reflectometer for neutral beam injection interlock on large helical device  

SciTech Connect

Neutral beam injection (NBI) into low-density plasmas can cause serious damage to the vacuum vessel wall. It is necessary to stop the NBI when the plasma terminates. This needs a reliable density monitor for NBI interlock. A three-channel homodyne reflectometer, installed on a large helical device was used for an NBI interlock. Microwaves of 28.5, 34.9, and 40.2 GHz were injected with O mode polarization. At present, a simple homodyne detection scheme is used. The reflected signal consists of a dc component due to local and reflected power and an ac component due to fluctuations in the position of the cutoff layer. Since the change in dc signal was very small, the root mean square value of the ac signal was used as the interlock signal. At present the 34.9 GHz O mode channel, whose O mode cutoff density is 1.5x10{sup 19} m{sup -3}, is used for the interlock. The system has been working since the first NBI experiments on LHD in 1999.

Tanaka, K.; Ejiri, A.; Ito, Y.; Kawahata, K.; Tokuzawa, T.; Osakabe, M.; Takeiri, Y. [National Institute for Fusion Science, Toki 509-5292 (Japan)

2006-10-15

255

Patterns In Contingencies: The Interlocking of Formal and Informal Political Institutions in Contemporary Argentina  

ERIC Educational Resources Information Center

This article explores how the interlocking of formal and informal political institutions has affected the dynamics and performance of the Argentine democracy. Key institutional features of the Argentine political system have been a competitive form of federalism, loosely structured and political parties that are not ideologically unified,…

Llamazares, Ivan

2005-01-01

256

Molecular self-assembly of arene-Ru based interlocked catenane metalla-cages.  

PubMed

Two interlocked trigonal prismatic metalla-cages are formed quantitatively through the self-assembly of ?-electron rich arene-Ru acceptors with a new tridentate donor. Interestingly, non-?-electron rich arene-Ru acceptors furnish simple trigonal prisms when they are combined with a tridentate donor. PMID:24888738

Mishra, Anurag; Dubey, Abhishek; Min, Jin Wook; Kim, Hyunuk; Stang, Peter J; Chi, Ki-Whan

2014-06-17

257

Control and Interlocking System for Bending Magnet Front-end at Indus-2  

SciTech Connect

We present control and interlock system developed for Indus-2 bending magnet front-end. The paper describes in detail the control of various signals associated with the front-end and the interlocking scheme implemented for the installed front-end. The number of signals associated with each front-end is {approx} 75. A control system is designed for monitoring temperature, pressure, airflow, water flow and control of vacuum gauges, fast shutter, water cooled shutter, safety shutter, pneumatic gate valves, sputter ion pump power supplies, beam position monitor etc. Two independent signals are generated for critical components that are used for software interlock and hard-wired interlock. The front-end control system is VME based and window 2000/XP workstation as an operator console. The CPU used is Motorola 68000-processor board of the VME bus having OS-9 real time operating system. One VME crate serves a cluster of 2-3 front ends. The communication between the VME and the workstation is linked over RS232 serial communication. The sputter ion power supplies are connected over isolated RS485 network. Critical protection features are implemented so that no single failure can render the system unsafe. This is implemented by providing two independent chains of protection (1) Hard wired in which relay logic is used and (2) Software. A Graphical User Interface (GUI) is developed using Lab view Version 7.0.

Kane, Sanjeev R.; Garg, Chander Kant; Nandedkar, R. V. [Synchrotron Utilization and Material Research Division, Raja Ramanna Centre for Advanced Technology, Indore-452013 (India)

2007-01-19

258

A two-ring interlocked DNA catenane rotor undergoing switchable transitions across three states.  

PubMed

A two-ring (?/?) interlocked DNA catenane rotor system is described. Using appropriate fuel and anti-fuel strands, the triggered switchable rotation across three states S1, S2 and S3 associated with the circular track of ring ? is demonstrated. PMID:24676286

Qi, Xiu-Juan; Lu, Chun-Hua; Cecconello, Alessandro; Yang, Huang-Hao; Willner, Itamar

2014-04-01

259

Family ties, Interlocking Directors and Performance of Business Groups in Emerging Countries  

Microsoft Academic Search

The effect of business groups on economic performance is controversial, both theoretically and empirically. We hypothesized that the seemingly contradictory empirical results can be explained by the differentiated governance structure of the business groups and, in particular, the role of social ties (family ties and interlocking directorates). Using a sample of Chilean firms, we analyzed the effects of social ties

Francisca Silvaa; Nicolás Majluf; Ricardo D. Paredes

260

Family ties, interlocking directors and performance of business groups in emerging countries: The case of Chile  

Microsoft Academic Search

The effect of business groups on economic performance is controversial, both theoretically and empirically. We hypothesized that the seemingly contradictory empirical results can be explained by the differentiated governance structure of the business groups and, in particular, the role of social ties (family ties and interlocking directorates). Using a sample of Chilean firms, we analyzed the effects of social ties

Francisca Silva; Nicolás Majluf; Ricardo D. Paredes

2006-01-01

261

INDOOR METAL CLAD SWITCH GEAR AND ALUMINUM INTERLOCKED CABLE INSTALLATION FOR CONTROLLING BOTH MAIN  

NASA Technical Reports Server (NTRS)

INDOOR METAL CLAD SWITCH GEAR AND ALUMINUM INTERLOCKED CABLE INSTALLATION FOR CONTROLLING BOTH MAIN AND SECONDARY DRIVES - THERE ARE 8 LINEUPS OF 6900 VOLT 500 MVA - WITH A TOTAL OF 29 CIRCUIT BREAKERS IN THE 10X10 FOOT WIND TUNNEL LUPA

1957-01-01

262

Design lessons from using programmable controllers in the MFTF-B personnel safety and interlocks system  

Microsoft Academic Search

Applying programmable controllers in critical applications such as personnel safety and interlocks systems requires special considerations in the design of both hardware and software. All modern programmable controller systems feature extensive internal diagnostic capabilities to protect against problems such as program memory errors; however most, if not all present designs lack an intrinsic capability for detecting and countering failures on

Branum

1983-01-01

263

Experimental Investigation About Stamping Behaviour of 3D Warp Interlock Composite Preforms  

NASA Astrophysics Data System (ADS)

Forming of continuous fibre reinforcements and thermoplastic resin commingled prepregs can be performed at room temperature due to its similar textile structure. The "cool" forming stage is better controlled and more economical. The increase of temperature and the resin consolidation phases after the forming can be carried out under the isothermal condition thanks to a closed system. It can avoid the manufacturing defects easily experienced in the non-isothermal thermoforming, in particular the wrinkling [1]. Glass/Polypropylene commingled yarns have been woven inside different three-dimensional (3D) warp interlock fabrics and then formed using a double-curved shape stamping tool. The present study investigates the in-plane and through-thickness behaviour of the 3D warp interlock fibrous reinforcements during forming with a hemispherical punch. Experimental data allow analysing the forming behaviour in the warp and weft directions and on the influence of warp interlock architectures. The results point out that the layer to layer warp interlock preform has a better stamping behaviour, in particular no forming defects and good homogeneity in thickness.

Dufour, Clément; Wang, Peng; Boussu, François; Soulat, Damien

2013-12-01

264

DUI risk prediction with alcohol biomarkers, interlock records, and self-report  

Microsoft Academic Search

The risk of impaired driving can be estimated through the use of several technologies but few programs utilize the full spectrum of predictive technologies and often underutilize the ones they do employ. The record of alcohol ignition interlock breath alcohol (BAC) tests are good predictors of future DUI risk, but still not widely used. These are a good, but imperfect

Paul Marques; Martin Javors; Fritz Pragst; Volker Auwaerter; Steina Aradottir; Christer Alling; Michel Yegles; Friedrich Wurst

2007-01-01

265

Controlled retainer-screw access placement for screw-retained implant prosthesis.  

PubMed

An implant-supported prosthesis is often secured to the underlying gold cylinders by retaining screws. There must be access to these screws from the oral surface of the prosthesis. Conventional preparation of this access is from the oral surface. This approach is difficult because the underlying gold cylinder is obscured. It may be damaged by a rotary cutting instrument as the access is prepared above it, because the cylinder cannot be seen during the preparation. Alternatively, the access hole may be unnecessarily enlarged in an attempt to find the cylinder. This loss of structure may weaken the prosthesis. A new approach, using 18-gauge stainless steel wire as a rotary cutting instrument, permits preparation of the access chamber from the intaglio surface of the prosthesis. This reduces risk of damage to the gold cylinder and is less destructive to the overlying material. PMID:9028229

Cohen, S R; Lawrence, S; Orenstein, J H; Appleby, D C; Blitzer, R M

1996-09-01

266

SCREW COMPRESSOR CHARACTERISTICS FOR HELIUM REFRIGERATION SYSTEMS  

SciTech Connect

The oil injected screw compressors have practically replaced all other types of compressors in modern helium refrigeration systems due to their large displacement capacity, minimal vibration, reliability and capability of handling helium's high heat of compression.At the present state of compressor system designs for helium systems, typically two-thirds of the lost input power is due to the compression system. Therefore it is important to understand the isothermal and volumetric efficiencies of these machines to help properly design these compression systems to match the refrigeration process. This presentation summarizes separate tests that have been conducted on Sullair compressors at the Superconducting Super-Collider Laboratory (SSCL) in 1993, Howden compressors at Jefferson Lab (JLab) in 2006 and Howden compressors at the Spallation Neutron Source (SNS) in 2006. This work is part of an ongoing study at JLab to understand the theoretical basis for these efficiencies and their loss

Ganni, Venkatarao; Knudsen, Peter; Creel, Jonathan; Arenius, Dana; Casagrande, Fabio; Howell, Matt

2008-03-01

267

Dynamic-locking-screw (DLS)-leads to less secondary screw perforations in proximal humerus fractures  

PubMed Central

Background Loss of reduction and screw perforation causes high failure rates in the treatment of proximal humerus fractures. The purpose of the present study was to evaluate the early postoperative complications using modern Dynamic Locking Screws (DLS 3.7) for plating of proximal humerus fractures. Methods Between 03/2009 and 12/2010, 64 patients with acute proximal humerus fractures were treated by angular stable plate fixation using DLSs in a limited multi-centre study. Follow-up examinations were performed three, six, twelve and twenty-four weeks postoperatively and any complications were carefully collected. Results 56 of 64 patients were examined at the six-month follow-up. Complications were observed in 12 patients (22%). In five cases (9%), a perforation of the DLS 3.7 occurred. Conclusions Despite the use of modern DLS 3.7, the early complications after plating of proximal humerus fractures remain high. The potential advantage of the DLS 3.7 regarding secondary screw perforation has to be confirmed by future randomized controlled trials.

2014-01-01

268

Effect of Frictions on the Ballistic Performance of a 3D Warp Interlock Fabric: Numerical Analysis  

NASA Astrophysics Data System (ADS)

3D interlock woven fabrics are promising materials to replace the 2D structures in the field of ballistic protection. The structural complexity of this material caused many difficulties in numerical modeling. This paper presents a new tool that permits to generate a geometry model of any woven fabric, then, mesh this model in shell or solid elements, and apply the mechanical properties of yarns to them. The tool shows many advantages over existing software. It is very handy in use with an organization of the functions in menu and using a graphic interface. It can describe correctly the geometry of all textile woven fabrics. With this tool, the orientation of the local axes of finite elements following the yarn direction facilitates defining the yarn mechanical properties in a numerical model. This tool can be largely applied because it is compatible with popular finite element codes such as Abaqus, Ansys, Radioss etc. Thanks to this tool, a finite element model was carried out to describe a ballistic impact on a 3D warp interlock Kevlar KM2® fabric. This work focuses on studying the effect of friction onto the ballistic impact behavior of this textile interlock structure. Results showed that the friction among yarns affects considerably on the impact behavior of this fabric. The effect of the friction between projectile and yarn is less important. The friction plays an important role in keeping the fabric structural stability during the impact event. This phenomenon explained why the projectile is easier to penetrate this 3D warp interlock fabric in the no-friction case. This result also indicates that the ballistic performance of the interlock woven fabrics can be improved by using fibers with great friction coefficients.

Ha-Minh, Cuong; Boussu, François; Kanit, Toufik; Crépin, David; Imad, Abdellatif

2012-06-01

269

Noninvasive method for retrieval of broken dental implant abutment screw.  

PubMed

Dental implants made of titanium for replacement of missing teeth are widely used because of ease of technical procedure and high success rate, but are not free of complications and may fail. Fracturing of the prosthetic screw continues to be a problem in restorative practice and great challenge to remove the fractured screw conservatively. This case report describes and demonstrates the technique of using an ultrasonic scaler in the removal of the fracture screw fragment as a noninvasive method without damaging the hex of implants. PMID:24963261

Gooty, Jagadish Reddy; Palakuru, Sunil Kumar; Guntakalla, Vikram Reddy; Nera, Mahipal

2014-04-01

270

A novel technique for accurate Poller (blocking) screw placement.  

PubMed

Achieving good results with intramedullary nailing of oblique long bone fractures at the metaphyseal-diaphyseal junction can be difficult. There is a strong tendency for axial displacement and an association with characteristic malalignment of the short fragment. Poller or blocking screws have been shown to be effective in aiding fracture reduction. While several papers describe methods for screw placement, these are confusing to understand, difficult to follow in clinical practice and not always applicable. Here we describe a new, simple, reproducible and easy to use method for ensuring accurate Poller screw placement, in order to maximise the benefits of their use and achieve good overall results. PMID:24629702

Hannah, Andrew; Aboelmagd, Tariq; Yip, Grace; Hull, Peter

2014-06-01

271

Noninvasive method for retrieval of broken dental implant abutment screw  

PubMed Central

Dental implants made of titanium for replacement of missing teeth are widely used because of ease of technical procedure and high success rate, but are not free of complications and may fail. Fracturing of the prosthetic screw continues to be a problem in restorative practice and great challenge to remove the fractured screw conservatively. This case report describes and demonstrates the technique of using an ultrasonic scaler in the removal of the fracture screw fragment as a noninvasive method without damaging the hex of implants.

Gooty, Jagadish Reddy; Palakuru, Sunil Kumar; Guntakalla, Vikram Reddy; Nera, Mahipal

2014-01-01

272

Vertebral Artery Dissect Injury with Brown-S?quard Syndrome by a Neural Foramen Penetrated Electric Screw Driver Bit : A Case Report  

PubMed Central

There are few reports in the literature of complete obstruction of the vertebral artery (VA) due to an electric screw driver bit penetration through the neural foramen into the spinal canal with Brown-Séquard syndrome (BSS). A 25-year-old man was admitted to the emergency department with a penetrated neck injury by an electric screw driver bit after a struggle. The patient presented the clinical features of BSS. Computed tomography scan revealed that the electric screw driver bit penetrated through the right neural foramen at the level of C3-4, and it caused an injury to the right half of the spinal cord. Emergent angiography revealed VA dissection, which was managed by immediate coil embolization at both proximal and distal ends of the injury site. After occlusion of the VA, the electric screw driver bit was extracted under general anesthesia. Bleeding was minimal and controlled without difficulties. No postoperative complications, such as wound dehiscence, CSF leakage, or infection, were noted. Endovascular approaches for occlusion of vertebral artery lesions are safe and effective methods of treatment.

Oh, Chang Hyun; Kim, Min Soo; Noh, Sung Hyun; Ji, Gyu Yeul

2013-01-01

273

Vertebral artery dissect injury with brown-séquard syndrome by a neural foramen penetrated electric screw driver bit : a case report.  

PubMed

There are few reports in the literature of complete obstruction of the vertebral artery (VA) due to an electric screw driver bit penetration through the neural foramen into the spinal canal with Brown-Séquard syndrome (BSS). A 25-year-old man was admitted to the emergency department with a penetrated neck injury by an electric screw driver bit after a struggle. The patient presented the clinical features of BSS. Computed tomography scan revealed that the electric screw driver bit penetrated through the right neural foramen at the level of C3-4, and it caused an injury to the right half of the spinal cord. Emergent angiography revealed VA dissection, which was managed by immediate coil embolization at both proximal and distal ends of the injury site. After occlusion of the VA, the electric screw driver bit was extracted under general anesthesia. Bleeding was minimal and controlled without difficulties. No postoperative complications, such as wound dehiscence, CSF leakage, or infection, were noted. Endovascular approaches for occlusion of vertebral artery lesions are safe and effective methods of treatment. PMID:24891861

Oh, Chang Hyun; Kim, Min Soo; Noh, Sung Hyun; Shin, Dong Ah; Ji, Gyu Yeul

2013-12-01

274

Effectiveness of ignition interlocks for preventing alcohol-impaired driving and alcohol-related crashes: a Community Guide systematic review.  

PubMed

A systematic review of the literature to assess the effectiveness of ignition interlocks for reducing alcohol-impaired driving and alcohol-related crashes was conducted for the Guide to Community Preventive Services (Community Guide). Because one of the primary research issues of interest--the degree to which the installation of interlocks in offenders' vehicles reduces alcohol-impaired driving in comparison to alternative sanctions (primarily license suspension)--was addressed by a 2004 systematic review conducted for the Cochrane Collaboration, the current review incorporates that previous work and extends it to include more recent literature and crash outcomes. The body of evidence evaluated includes the 11 studies from the prior review, plus four more recent studies published through December 2007. The installation of ignition interlocks was associated consistently with large reductions in re-arrest rates for alcohol-impaired driving within both the earlier and later bodies of evidence. Following removal of interlocks, re-arrest rates reverted to levels similar to those for comparison groups. The limited available evidence from three studies that evaluated crash rates suggests that alcohol-related crashes decrease while interlocks are installed in vehicles. According to Community Guide rules of evidence, these findings provide strong evidence that interlocks, while they are in use in offenders' vehicles, are effective in reducing re-arrest rates. However, the potential for interlock programs to reduce alcohol-related crashes is currently limited by the small proportion of offenders who participate in the programs and the lack of a persistent beneficial effect once the interlock is removed. Suggestions for facilitating more widespread and sustained use of ignition interlocks are provided. PMID:21335270

Elder, Randy W; Voas, Robert; Beirness, Doug; Shults, Ruth A; Sleet, David A; Nichols, James L; Compton, Richard

2011-03-01

275

Direct Arthroscopic Distal Clavicle Resection  

PubMed Central

Degenerative change involving the acromioclavicular (AC) is frequently seen as part of a normal aging process. Occasionally, this results in a painful clinical condition. Although AC joint symptoms commonly occur in conjunction with other shoulder pathology, they may occur in isolation. Treatment of isolated AC joint osteoarthritis is initially non-surgical. When such treatment fails to provide lasting relief, surgical treatment is warranted. Direct (superior) arthroscopic resection of the distal (lateral) end of the clavicle is a successful method of treating the condition, as well as other isolated conditions of the AC joint. The following article reviews appropriate patient evaluation, surgical indications and technique.

Lervick, Gregory N

2005-01-01

276

Does ischial screw fixation improve mechanical stability in revision total hip arthroplasty?  

PubMed

Ischial screw fixation, albeit technically challenging, is postulated to provide additional mechanical stability in revision total hip arthroplasty (THA). Hemipelvis specimens were prepared to simulate revision THA, and an acetabular component with supplemental screw fixation was implanted. Three configurations were tested: 2 dome screws alone, 2 dome screws plus an additional screw within the dome, and 2 dome screws plus an ischial screw. Force displacement data were acquired during mechanical testing. An increase in mechanical stability was observed in acetabular components with supplemental screw fixation into either the posterior column or ischium (P?.031) compared to isolated dome fixation. In addition, supplemental ischial screw fixation may provide a modest advantage over a screw placed posteroinferiorly within the acetabular dome during revision THA. PMID:19679432

Meneghini, R Michael; Stultz, Allison D; Watson, Jill S; Ziemba-Davis, Mary; Buckley, Christine A

2010-10-01

277

Stress analysis of a centrally fractured rib fixated by an intramedullary screw.  

PubMed

The stress on an intramedullary screw rib fixation device holding together a centrally fractured human rib under in vivo force loadings was studied using finite element analysis (FEA). Validation of the FEA modelling using pullout from porcine ribs proved FEA to be suitable for assessing the structural integrity of screw/bone systems such as rib fixated by a screw. In the human rib fixation investigation, it was found that intramedullary bioresorbable Bioretec screws can fixate centrally fractured human ribs under normal breathing conditions. However, under coughing conditions, simulation showed Bioretec fixating screws to bend substantially. High stresses in the screw are mainly the result of flexion induced by the force loading, and are restricted to thin regions on the outside of the screw shaft. Stiffer screws result in less locally intense stress concentrations in bone, indicating that bone failure in the bone/screw contact regions can be averted with improvements in screw stiffness. PMID:23098197

Liovic, Petar; Sutalo, Ilija D; Marasco, Silvana F

2014-07-01

278

Comparison of straight median sternotomy and interlocking sternotomy with respect to biomechanical stability  

PubMed Central

AIM: To increase the stability of sternotomy and so decrease the complications because of instability. METHODS: Tests were performed on 20 fresh sheep sterna which were isolated from the sterno-costal joints of the ribs. Median straight and interlocking sternotomies were performed on 10 sterna each, set as groups 1 and 2, respectively. Both sternotomies were performed with an oscillating saw and closed at three points with a No. 5 straight stainless-steel wiring. Fatigue testing was performed in cranio-caudal, anterio-posterior (AP) and lateral directions by a computerized materials-testing machine cycling between loads of 0 to 400 N per 5 s (0.2 Hz). The amount of displacement in AP, lateral and cranio-caudal directions were measured and also the opposing bone surface at the osteotomy areas were calculated at the two halves of sternum. RESULTS: The mean displacement in cranio-caudal direction was 9.66 ± 3.34 mm for median sternotomy and was 1.26 ± 0.97 mm for interlocking sternotomy, P < 0.001. The mean displacement in AP direction was 9.12 ± 2.74 mm for median sternotomy and was 1.20 ± 0.55 mm for interlocking sternotomy, P < 0.001. The mean displacement in lateral direction was 8.95 ± 3.86 mm for median sternotomy and was 7.24 ± 2.43 mm for interlocking sternotomy, P > 0.001. The mean surface area was 10.40 ± 0.49 cm² for median sternotomy and was 16.8 ± 0.78 cm² for interlocking sternotomy, P < 0.001. The displacement in AP and cranio-caudal directions is less in group 2 and it is statistically significant. Displacement in lateral direction in group 2 is less but it is statistically not significant. Surface area in group 2 is significantly wider than group 1. CONCLUSION: Our test results demonstrated improved primary stability and wider opposing bone surfaces in interlocking sternotomy compared to median sternotomy. This method may provide better healing and less complication rates in clinical setting, further studies are necessary for its clinical implications.

Kucukdurmaz, Fatih; Ag?r, Ismail; Bezer, Murat

2013-01-01

279

[Variations of transpedicular screw fixation and spinal dura opening].  

PubMed

The paper presents modified treatment protocols for spinal trauma and degenerative disease--transpedicular screw fixation based upon biomechanical adjustment and spinal dura opening. Both methods help to improve results of surgical treatment and decrease complication rate. PMID:23033595

Tumakaev, R F

2012-01-01

280

Screw-Type Compressors for Use in Heat Pump Systems.  

National Technical Information Service (NTIS)

Due to its particular advantages, i.e., small dimensions with relatively large volume flow velocity, high operational reliability and large control region, the screw-type compressor has gained wide acceptance in industrial refrigeration engineering. Air c...

R. Klein

1977-01-01

281

21. NBS SUIT LAB. THREE GLOVES, HELMET, AND SCREW DRIVER ...  

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

21. NBS SUIT LAB. THREE GLOVES, HELMET, AND SCREW DRIVER TORQUE WRENCH FOR ASSEMBLY AND REPAIR OF BOTH. - Marshall Space Flight Center, Neutral Buoyancy Simulator Facility, Rideout Road, Huntsville, Madison County, AL

282

Biocompatibility studies of titanium-based alloy pedicle screw and rod system  

Microsoft Academic Search

Background context: Few histological studies of pedicle screw and rod systems have been done, and spinal surgery with pedicle screw and rod system is increasing.Purpose: To know the biocompatibility of pedicle screw and rod systems histologically. Study design\\/setting: Titanium-based alloy pedicle screws were removed from 20 patients. Histological studies of the tissue response to the screws were performed by light

Kazuhiro Yamaguchi; Hiroaki Konishi; Shinichiro Hara; Yoshinori Motomura

2001-01-01

283

Surface polishing positively influences ease of plate and screw removal.  

PubMed

Difficulties removing temporary fracture fixation devices due to excessive bony on-growth results in extended surgical time leading to excessive blood loss, debris contamination and potentially refracture. Commercially available locking plates and screws are manufactured for clinics with a micro-rough surface, which contributes to the excessive bony on-growth reported. We have applied polishing technology to commercially pure titanium locking compression plates (LCP) and titanium-6%aluminium-7%niobium (TAN) plates and screws to assess if it can alleviate problems with strong bony overgrowth. Samples were implanted for 6, 12 and 18 months in a bilateral sheep tibia non fracture model and assessed for screw removal torque, percentage of bone contact and tissue-material response. Both electropolishing (p=0.001) and paste polishing (p=0.010) of TAN screws significantly reduced the mean torque required for removal compared to their micro-rough counterparts. This was accompanied by a trend for a lower percentage of bone contact for polished screws. This difference in bone contact was significant for paste polished TAN screws (p<0.001 parallel but not electropolished TAN screws (p=0.066). Ex vivo, soft tissue removal was much easier (approximately five minutes) for polished constructs, which was difficult and at least four times longer for standard micro-rough constructs. We suggest that polishing of locked plate/screw systems will improve ease of removal and reduce implant related removal complications encountered due to excessive strong bony on-growth while maintaining biocompatibility and implant stability. Future studies aim to assess the potential of this technology in the next level of complication, a fracture model. PMID:20186671

Hayes, J S; Seidenglanz, U; Pearce, A I; Pearce, S G; Archer, C W; Richards, R G

2010-01-01

284

Biomechanical Behaviour of Double Threaded Screw in Tibia Fixation  

Microsoft Academic Search

The aim of the work was assessment of stability of tibia fixation realized with the use of double threaded screw. Biomechanical\\u000a analysis of the tibia – double threaded screw system was carried our for the implant made of two biomaterials used in bone\\u000a surgery – Cr-Ni-Mo stainless steel and Ti-6Al-4V alloy. Finite element method was applied to calculate displacements, strains

Witold Walke; Jan Marciniak; Zbigniew Paszenda; Marcin Kaczmarek; Jerzy Cieplak

2008-01-01

285

Screw thread parameter measurement system based on image processing method  

NASA Astrophysics Data System (ADS)

In the industrial production, as an important transmission part, the screw thread is applied extensively in many automation equipments. The traditional measurement methods of screw thread parameter, including integrated test methods of multiparameters and the single parameter measurement method, belong to contact measurement method. In practical the contact measurement exists some disadvantages, such as relatively high time cost, introducing easily human error and causing thread damage. In this paper, as a new kind of real-time and non-contact measurement method, a screw thread parameter measurement system based on image processing method is developed to accurately measure the outside diameter, inside diameter, pitch diameter, pitch, thread height and other parameters of screw thread. In the system the industrial camera is employed to acquire the image of screw thread, some image processing methods are used to obtain the image profile of screw thread and a mathematics model is established to compute the parameters. The C++Builder 6.0 is employed as the software development platform to realize the image process and computation of screw thread parameters. For verifying the feasibility of the measurement system, some experiments were carried out and the measurement errors were analyzed. The experiment results show the image measurement system satisfies the measurement requirements and suitable for real-time detection of screw thread parameters mentioned above. Comparing with the traditional methods the system based on image processing method has some advantages, such as, non-contact, easy operation, high measuring accuracy, no work piece damage, fast error analysis and so on. In the industrial production, this measurement system can provide an important reference value for development of similar parameter measurement system.

Rao, Zhimin; Huang, Kanggao; Mao, Jiandong; Zhang, Yaya; Zhang, Fan

2013-08-01

286

Inertia Compensation While Scanning Screw Threads on Coordinate Measuring Machines  

NASA Astrophysics Data System (ADS)

Usage of scanning coordinate-measuring machines for inspection of screw threads has become a common practice nowadays. Compared to touch trigger probing, scanning capabilities allow to speed up the measuring process while still maintaining high accuracy. However, in some cases accuracy drastically depends on the scanning speed. In this paper a compensation method is proposed allowing to reduce the influence of inertia of the probing system while scanning screw threads on coordinate-measuring machines.

Kosarevsky, Sergey; Latypov, Viktor

2010-01-01

287

Intramedullary screw fixation for midshaft fractures of the clavicle  

Microsoft Academic Search

Open intramedullary fixation of 37 fresh midshaft clavicular fractures in 35 patients was performed using a 6.5 partially\\u000a threaded cancellous screw. Mean age was 38 years (range 18–65). The screw was inserted from the medial fragment after retrograde\\u000a drilling of that fragment. Average follow-up period was 21 months (range 9–36). Radiological evidence of union was apparent\\u000a in all cases within six to

Ayman Khalil

2009-01-01

288

Posterior Atalntoaxial Fusion with C1 Lateral Mass Screw and C2 Pedicle Screw Supplemented with Miniplate Fixation for Interlaminar Fusion : A Preliminary Report  

PubMed Central

Objective To investigate the feasibility of C1 lateral mass screw and C2 pedicle screw with polyaxial screw and rod system supplemented with miniplate for interlaminar fusion to treat various atlantoaxial instabilities. Methods After posterior atlantoaxial fixation with lateral mass screw in the atlas and pedicle screw in the axis, we used 2 miniplates to fixate interlaminar iliac bone graft instead of sublaminar wiring. We performed this procedure in thirteen patients who had atlantoaxial instabilities and retrospectively evaluated the bone fusion rate and complications. Results By using this method, we have achieved excellent bone fusion comparing with the result of other methods without any complications related to this procedure. Conclusion C1 lateral mass screw and C2 pedicle screw with polyaxial screw and rod system supplemented with miniplate for interlaminar fusion may be an efficient alternative method to treat various atlantoaxial instabilities.

Yoon, Sang-Mok; Baek, Jin-Wook

2012-01-01

289

Clinical applications of drill free screws in maxillofacial surgery.  

PubMed

Drill free screws are newly designed osteosynthesis screws with specially formed tips and cutting flutes, which act like a cork-screw and can be inserted into bone without predrilling. A prospective study on 82 patients was performed in order to investigate the efficiency of mini- and micro-drill free screws (DFS) in clinical use and to find out areas in maxillofacial traumatology and orthognathic surgery, where the application of this new type of screw may be recommended. Thirty-eight Le-Fort-osteotomies, 23 central and lateral midfacial fractures and 21 fractures of the mandible were fixed using the Champy titanium micro/miniplate system and in total 518 center-drive titanium micro-DFS (1.5 mm) and 392 center-drive titanium mini-DFS (2 mm) with lengths between 4 and 7 mm. The results showed that the grip of micro- and mini-DFS was sufficient for the fixation of bone fragments in the central and lateral midface and in the mandibular area. The insertion of DFS was simple and is recommended in the area of the central midface; the insertion of the screws was difficult, but possible in the anterior mandible and in the lateral midface. The application of DFS in the mandibular angle region is not recommended. PMID:10626259

Heidemann, W; Gerlach, K L

1999-08-01

290

Screw driver: an unusual cause of cervical spinal cord injury  

PubMed Central

Non-missile penetrating spinal injuries are rare. Screw driver injury, more especially to the cervical spine, represents an even rarer subset. To our knowledge, this is the first reported case from West Africa of cervical spinal cord injury from a screw driver. A middle-aged man was stabbed from the back with a screw driver. He presented with right-sided C4 Brown-Sequard syndrome with the impaling object in situ. Cervical spine x-rays showed the screw driver to have gone into the spine between the spinous processes of C4 and C5, traversing the spinal canal and lodged in the anterior part of the C4/5 intervertebral disc space. C4 and C5 laminectomies were performed and the screw driver removed under vision. The object was found to have traversed the right side of the cervical spinal cord. The dural tear was repaired. He had some neurologic improvement initially, but later declined. He died from severe pulmonary complications 2 weeks postinjury. Screw driver represents an unusual cause of non-missile penetrating cervical spinal injury. Its neurological effects and complications of the cord injury lead to significant morbidity and mortality.

Rabiu, Taopheeq Bamidele; Aremu, Abayomi Adeniran; Amao, Olusegun Adetunji; Awoleke, Jacob Olumuyiwa

2011-01-01

291

Safety and reliability assessment of the EDS (Engineering Demonstration System) Hardwire Interlock System using extended fault trees.  

National Technical Information Service (NTIS)

A safety and reliability assessment of the Laser Isotope Separation (LIS) Engineering Demonstration System (EDS) Hardwire Interlock System (HIS) has been completed. A major objective of the assessment was to identify any single-point failures in the HIS t...

G. C. Corynen

1990-01-01

292

Ankle fractures involving the fibula proximal to the distal tibiofibular syndesmosis.  

PubMed

Thirty-two cases of ankle fractures associated with fibular fractures above the distal tibiofibular syndesmosis were studied. All were treated with open reduction and internal fixation. The average follow-up was 25 months. The results of the postoperative evaluation were rated, based on subjective clinical criteria, as good, fair, and poor. According to the Lauge-Hansen classification, there were 17 (53%) cases of supination-external rotation injury (2 stage 2 and 15 stage 4), 9 (28%) cases of stage 3 pronation-abduction injury, and 6 (19%) cases of pronation-external rotation injury (3 stage 3 and 3 stage 4). All cases could be classified as Weber type C or as suprasyndesmotic, fibular diaphyseal fracture (44-C) according to the Orthopaedic Trauma Association classification. In 18 (56%) cases, the fracture was associated with ankle dislocation. There were seven (22%) open fractures, (two grade I, four grade II, and one grade IIIA). Syndesmotic screws were used in 23 (72%) cases (12 supination-external rotation injury, 6 pronation-external rotation injury, and 5 pronation-abduction injury). The syndesmotic screw was removed after an average of 9 weeks. Four (13%) nonunions and two (6%) delayed unions of the fibula were treated with bone grafting and/or hardware revision and eventually healed. Three of the nonunions had poor clinical results because of degenerative ankle joint arthritis in two (one of them ended in arthrodesis) and deep infection, which was eventually cured, in the third. The fourth nonunion had a fair result. One of the delayed unions had a fair result (an obese patient) and the other had a good result. Two patients developed deep infections; one ended in gangrene and amputation in a diabetic patient, and the other was a patient with fibular nonunion that eventually healed. Three patients had superficial infections that were treated successfully. Of the 32 cases, 23 (72%) showed good results, 4 (13%) showed fair results, and 5 (16%) showed poor results. The cases with poor results included three fibular nonunions, one deep infection, and one recurrent superficial infection and wound dehiscence after hardware removal. A syndesmotic screw is usually needed in cases of fracture-dislocations. Two patients with occult fibular nonunions developed diastasis of the syndesmosis after removal of the syndesmotic screw. It was found that reduction and temporary pinning of the distal tibiofibular joint helps achieve fibular length, which is crucial to restoring the biomechanics of the ankle joint. It seems advisable not to remove the syndesmotic screw until there are signs of healing of fibular fracture to avoid diastasis of the distal tibiofibular joint. Bone grafting should be considered in high energy fractures with comminution. These complex injuries are associated with higher rates of complications. Poor results can be attributed to fracture factors, e.g., open fractures, infections; patient factors, e.g., obesity, lowered immunity as in diabetes, and noncompliance; and iatrogenic factors, e.g., early removal of syndesmotic screws. PMID:9278748

Ebraheim, N A; Mekhail, A O; Gargasz, S S

1997-08-01

293

Fixation strength of biocomposite wedge interference screw in ACL reconstruction: effect of screw length and tunnel/screw ratio. A controlled laboratory study  

PubMed Central

Background Primary stability of the graft is essential in anterior cruciate ligament surgery. An optimal method of fixation should be easy to insert and provide great resistance against pull-out forces. A controlled laboratory study was designed to test the primary stability of ACL tendinous grafts in the tibial tunnel. The correlation between resistance to traction forces and the cross-section and length of the screw was studied. Methods The tibial phase of ACL reconstruction was performed in forty porcine tibias using digital flexor tendons of the same animal. An 8 mm tunnel was drilled in each specimen and two looped tendons placed as graft. Specimens were divided in five groups according to the diameter and length of the screw used for fixation. Wedge interference screws were used. Longitudinal traction was applied to the graft with a Servohydraulic Fatigue System. Load and displacement were controlled and analyzed. Results The mean loads to failure for each group were 295,44 N (Group 1; 9 × 23 screw), 564,05 N (Group 2; 9 × 28), 614,95 N (Group 3; 9 × 35), 651,14 N (Group 4; 10 × 28) and 664,99 (Group 5; 10 × 35). No slippage of the graft was observed in groups 3, 4 and 5. There were significant differences in the load to failure among groups (ANOVA/P < 0.001). Conclusions Longer and wider interference screws provide better fixation in tibial ACL graft fixation. Short screws (23 mm) do not achieve optimal fixation and should be implanted only with special requirements.

2010-01-01

294

Interlocked feedforward loops control cell type-specific Rhodopsin expression in the Drosophila eye  

PubMed Central

How complex networks of activators and repressors lead to exquisitely specific cell type determination during development is poorly understood. In the Drosophila eye, expression patterns of Rhodopsins define at least eight functionally distinct though related subtypes of photoreceptors. Here, we describe a role for the transcription factor gene defective proventriculus (dve) as a critical node in the network regulating Rhodopsin expression. dve is a shared component of two opposing, interlocked feedforward loops (FFLs). Orthodenticle and Dve interact in an incoherent FFL to repress Rhodopsin expression throughout the eye. In the R7 and R8 photoreceptors, a coherent FFL relieves repression by Dve while activating Rhodopsin expression. Therefore, this network uses repression to restrict, and combinatorial activation to induce cell type-specific expression. Further, Dve levels are finely tuned to yield cell type- and region-specific repression or activation outcomes. This interlocked FFL motif may be a general mechanism to control terminal cell fate specification.

Johnston, Robert J.; Otake, Yoshiaki; Sood, Pranidhi; Vogt, Nina; Behnia, Rudy; Vasiliauskas, Daniel; McDonald, Elizabeth; Xie, Baotong; Koenig, Sebastian; Wolf, Reinhard; Cook, Tiffany; Gebelein, Brian; Kussell, Edo; Nagakoshi, Hideki; Desplan, Claude

2011-01-01

295

A simple method for fashioning an antibiotic cement-coated interlocking intramedullary nail.  

PubMed

Acute or chronic infection in the presence of nonunited fracture or chronic nonunion often necessitates staged surgical treatment. Treatment typically involves removal of hardware, débridement of infected tissue, use of local antibiotic delivery, and a long-term course of intravenous antibiotics. Several methods of local antibiotic delivery using antibiotic-impregnated polymethylmethacrylate (PMMA) have been commonly used, including commercial or hand-fashioned PMMA beads, antibiotic spacers, and antibiotic PMMA-coated guide rods. While these methods address the problem of infection, they do little to address fracture stability. In this report we describe a simple method for fashioning an antibiotic cement-coated interlocking intramedullary nail to treat an infected tibia fracture. This technique capitalizes on local delivery of antibiotics through use of antibiotic cement with the added benefit of improving fracture stability and fixation with an interlocking nail to achieve bony union. PMID:20305835

Riel, Ryan U; Gladden, Paul B

2010-01-01

296

Design lessons from using programmable controllers in the MFTF-B personnel safety and interlocks system  

SciTech Connect

Applying programmable controllers in critical applications such as personnel safety and interlocks systems requires special considerations in the design of both hardware and software. All modern programmable controller systems feature extensive internal diagnostic capabilities to protect against problems such as program memory errors; however most, if not all present designs lack an intrinsic capability for detecting and countering failures on the field-side of their I/O modules. Many of the most common styles of I/O modules can also introduce potentially dangerous sneak circuits, even without component failure. This paper presents the most significant lessons learned to date in the design of the MFTF-B Personnel Safety and Interlocks System, which utilizes two non-redundant programmable controllers with over 800 I/O points each. Specific problems recognized during the design process as well as those discovered during initial testing and operation are discussed along with their specific solutions in hardware and software.

Branum, J.D.

1983-11-29

297

Finite element simulation of three?dimensional angle?interlock woven fabric undergoing ballistic impact  

Microsoft Academic Search

This paper presents finite element simulations of three?dimensional (3D) angle?interlock woven fabric (3DAWF) undergoing ballistic impact. A micro?structure model of the 3DAWF was established at the fiber tow level. Incorporated with commercial finite element code, ABAQUS\\/Explicit, the ballistic impact damage of the 3DAWF was simulated and compared with that in the experiment. Residual velocities of the conically cylindrical steel projectile

Limin Jin; Baozhong Sun; Bohong Gu

2011-01-01

298

Successful Embolization of Coronary Arteriovenous Fistula Using an Interlocking Detachable Coil  

Microsoft Academic Search

.   Although the efficacy and feasibility of coil embolization of coronary arteriovenous fistulas have been reported, the procedure\\u000a may be complicated by migration of the coil into peripheral vessels or pulmonary arteries. We report two cases of successful\\u000a coil embolization of such lesions using an interlocking detachable coil. This system can provide safer and more effective\\u000a coil embolization in patients

Y. Ogoh; T. Akagi; T. Abe; K. Hashino; N. Hayabuchi; H. Kato

1997-01-01

299

Compressive behavior of 3-D angle-interlock woven fabric composites at various strain rates  

Microsoft Academic Search

The compressive properties of 3-D angle-interlock E-glass\\/vinyl ester woven composites at quasi-static and high strain rate loadings have been investigated to evaluate the compressive failure mode at different strain rates. The through-thickness compressive properties at high strain rates from 800 to 2700s?1 were tested using the split Hopkinson pressure bar (SHPB) technique. The compressive properties at quasi-static strain rate were

Baozhong Sun; Bohong Gu; Xin Ding

2005-01-01

300

Effect of washing cycles on behavior of core spun cotton\\/spandex interlock structures  

Microsoft Academic Search

Effect of machine washing on structural behavior of core spun cotton\\/spandex interlock fabrics made with high, medium and\\u000a low tightness factors has been investigated. Results are compared with those for similar fabrics knitted from 100 % cotton.\\u000a Structural behavior of cotton\\/spandex and cotton fabric samples was observed under full relaxation and washing treatments\\u000a up to 10th cycle. Based on these

C. N. Herath; Bok Choon Kang

2009-01-01

301

Development of an interlocked nail for segmental defects in the rabbit tibia.  

PubMed

Previous animal models have been developed to study intramedullary nailing for challenging segmental defects in the tibia. In large animals, interlocked nail fixation created a stable environment suitable to study new bone growth technologies placed in the defect. To our knowledge, there are no comparable interlocked tibial defect models for the rabbit in which new technologies could be evaluated. Such a model would be helpful since the rabbit is a popular initial model for orthopedic research studies owing to its wide availability and low cost. While numerous studies have nailed the rabbit tibia, all were non-locked implants that allowed some degree of instability between the fracture fragments. In addition, the non-locked nails were constructed of stainless steel, whereas human nails are increasingly made from titanium alloy. In the current study, an interlocked titanium nail was developed for the rabbit tibia. It was implanted in cadaver tibiae and subjected to fatigue cycling in combined compression and bending at physiologic levels to 21,061 cycles. This duration is estimated to represent 12 weeks of gait by the animal. Before and after fatigue cycling, monotonic testing was performed in compression and bending at physiologic levels. The intact contralateral limbs served as controls. All limbs completed the cycling; the instrumented limbs exhibited interfragmentary cyclic strain amplitudes during fatigue (616 +/- 139 micro-strain), which was significantly greater than the control limbs (136 +/- 35 microstrain). Monotonic strain amplitudes for the test limbs in bending and compression were 4839 +/- 1028 and 542 +/- 122 microstrain, respectively; corresponding values for the control bones were 407 +/- 118 and 95 +/- 38 microstrain, respectively. These data are similar to those presented in prior studies in larger bone models. The current study presents one method for interlocked nail fixation for this complex tibial shaft fracture in a small animal. PMID:22611873

LeCronier, David J; Papakonstantinou, John S; Gheevarughese, Vineetha; Beran, Casey D; Walter, Norman E; Atkinson, Patrick J

2012-04-01

302

Attitude and Interlock Angle Estimation Using Split-Field-of-View Star Tracker1  

Microsoft Academic Search

An efficient Kalman filter based algorithm has been proposed for the spacecraft attitude estimation problem using a novel split-field-of-view star camera and three-axis rate gyros. The conventional spacecraft attitude algorithm has been modified for on-orbit estimation of interlock angles between the two fields of view of star camera, gyro axis, and the spacecraft body frame. Real time estimation of the

Puneet Singla; D. Todd Griffith; Anup Katake; John L. Junkins

303

?????????????????????????? ?????????????????????????????????????????????????? ??????????? ????????????????????? ??????????????????????????????? Effect of Screw Rotating Speed on the Properties of Poly lactic acid(PLA)\\/Organoclay Nanocomposites Prepared by a Twin Screw Extruder  

Microsoft Academic Search

This study analyzes the effect of different screw rotating speeds on the properties of nanocomposites prepared by melt compounding PLA with an organoclay in a co-rotating twin-screw extruder. Polyamide 12 was used as an additive. Two different screw rotating speeds, 65 rpm and 150 rpm, were used in this study. According to the tensile strength data, the Young's modulus and

Aniwat Hasook; Hiroki Muramatsu; Shuichi Tanoue; Yoshiyuki Iemoto; Tsunemune Unryu

304

Efficacy of different fixation devices in maintaining an initial reduction for surgically managed distal radius fractures  

PubMed Central

Background Fracture of the distal radius is a common injury. Many treatment options exist for the surgical management of extra-articular and intra-articular distal radius fractures. The best method of treatment for these fractures remains controversial. We sought to examine radiographic outcomes of patients treated with non-spanning external fixator (NSEF), open reduction and internal fixation (ORIF) with locking plates and screws or closed reduction and percutaneous pinning (CRPP) and compare their ability to maintain radiographic parameters over the initial 6-week postoperative period. Methods We performed a retrospective review of radiographs showing 211 distal radius fractures treated with NSEF, ORIF or CRPP. We examined the images for a variety of radiological parameters. Measurements were taken immediately postoperatively and at 6-week follow-up to determine whether there was any loss of reduction. Results Of the 211 fractures, 104 (49.3%) were type-A fractures, 12 (5.7%) were type-B fractures and 95 (45.0%) were type-C fractures. The 3 treatments maintained the reduction obtained at surgery until healing. The CRPP and ORIF treatments failed to maintain correction in ulnar variance for the 6-week period; however, only ORIF actually changed the ulnar variance from presurgical values. Conclusion Treatment with ORIF for comminuted, intra-articular distal radius fractures produces good radiographic results with maintenance of surgical radiographic parameters, whereas NSEFand CRPP of less complex fractures also provide good results. This suggests that fracture-specific fixation with CRPP or NSEF are sufficient for certain distal radius fractures.

Geller, Loren; Bernstein, Mitchell; Carli, Alberto; Berry, Greg; Reindl, Rudy; Harvey, Edward

2009-01-01

305

Atlantoaxial fixation using the polyaxial screw-rod system  

PubMed Central

The aim of this study is to evaluate the first results of the atlantoaxial fixation using polyaxial screw–rod system. Twenty-eight patients followed-up 12–29 months (average 17.1 months) were included in this study. The average age was 59.5 years (range 23–89 years). The atlantoaxial fusion was employed in 20 patients for an acute injury to the upper cervical spine, in 1 patient with rheumatoid arthritis for atlantoaxial vertical instability, in 1 patient for C1–C2 osteoarthritis, in 2 patients for malunion of the fractured dens. Temporary fixation was applied in two patients for type III displaced fractures of the dens and in two patients for the atlantoaxial rotatory dislocation. Retrospectively, we evaluated operative time, intraoperative bleeding and the interval of X-ray exposure. The resulting condition was subjectively evaluated by patients. We evaluated also the placement, direction and length of the screws. Fusion or stability in the temporary fixation was evaluated on radiographs taken at 3, 6, 12 weeks and 6 and 12 months after the surgery. As concerns complications, intraoperatively we monitored injury of the nerve structures and the vertebral artery. Monitoring of postoperative complications was focused on delayed healing of the wound, breaking or loosening of screws and development of malunion. Operative time ranged from 35 to 155 min, (average 83 min). Intraoperative blood loss ranged from 50 to 1,500 ml (average 540 ml). The image intensifier was used for a period of 24 s to 2 min 36 s (average 1 min 6 s). Within the postoperative evaluation, four patients complained of paresthesia in the region innervated by the greater occipital nerve. A total of 56 screws were inserted into C1, their length ranged from 26 to 34 mm (average, 30.8 mm). All screws were positioned correctly in the C1 lateral mass. Another 56 screws were inserted into C2. Their length ranged from 28 to 36 mm (average 31.4 mm). Three screws were malpositioned: one screw perforated the spinal canal and two screws protruded into the vertebral artery canal. C1–C2 stability was achieved in all patients 12 weeks after the surgery. No clinically manifested injury of the vertebral artery or nerve structures was observed in any of these cases. As for postoperative complications, we recorded wound dehiscence in one patient. The Harms C1–C2 fixation is a very effective method of stabilizing the atlantoaxial complex. The possibility of a temporary fixation without damage to the atlantoaxial joints and of reduction after the screws and rods had been inserted is quite unique.

Vyskocil, Tomas; Sebesta, Petr; Kryl, Jan

2006-01-01

306

Modelling the evolution of a bi-partite network Peer referral in interlocking directorates*  

PubMed Central

A central part of relational ties between social actors are constituted by shared affiliations and events. The action of joint participation reinforces personal ties between social actors as well as mutually shared values and norms that in turn perpetuate the patterns of social action that define groups. Therefore the study of bipartite networks is central to social science. Furthermore, the dynamics of these processes suggests that bipartite networks should not be considered static structures but rather be studied over time. In order to model the evolution of bipartite networks empirically we introduce a class of models and a Bayesian inference scheme that extends previous stochastic actor-oriented models for unimodal graphs. Contemporary research on interlocking directorates provides an area of research in which it seems reasonable to apply the model. Specifically, we address the question of how tie formation, i.e. director recruitment, contributes to the structural properties of the interlocking directorate network. For boards of directors on the Stockholm stock exchange we propose that a prolific mechanism in tie formation is that of peer referral. The results indicate that such a mechanism is present, generating multiple interlocks between boards.

Edling, Christofer

2010-01-01

307

In vivo loss of cement-bone interlock reduces fixation strength in total knee arthroplasties.  

PubMed

Prevention of aseptic loosening of total knee arthroplasties (TKAs) remains a clinical challenge. Understanding how changes in morphology at the implant-bone interface with in vivo service affect implant stability and strength could lead to new approaches to mitigate loosening. Enbloc TKA retrievals and freshly-cemented TKA tibial components were used to determine if the mechanical strength of the interface depended on the amount of cement-bone interlock and the morphology of the supporting bone under the cement layer. Implants were sectioned into small specimens of the cement-interface-bone from under the tibial tray. Micro-CT scans were used to document interlock morphology and architecture of the supporting trabecular bone. Axial compression tests were used to assess mechanical behavior. Postmortem retrievals had lower contact fraction (42?±?55%) compared to freshly-cemented constructs (121?±?61%) (p?=?0.0008). Supporting bone architecture parameters were not different for the two groups. Increased interface contact fraction and supporting bone volume fraction (BV/TV) were positive predictors of interface strength (r(2) ?=?0.72, p?=?0.0001). For the same supporting bone BV/TV, postmortem specimens had weaker interfaces; they were also more compliant. Cemented TKAs with in vivo service experience a loss of fixation strength and increased micro-motion due to the loss of cement-bone interlock. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1052-1060, 2014. PMID:24777486

Goodheart, Jacklyn R; Miller, Mark A; Mann, Kenneth A

2014-08-01

308

Extending DIII-D Neutral Beam Modulated Operations with a Camac Based Total on Time Interlock  

SciTech Connect

A new total-on-time interlock has increased the operational time limits of the Neutral Beam systems at DIII-D. The interlock, called the Neutral Beam On-Time-Limiter (NBOTL), is a custom built CAMAC module utilizing a Xilinx 9572 Complex Programmable Logic Device (CPLD) as its primary circuit. The Neutral Beam Injection Systems are the primary source of auxiliary heating for DIII-D plasma discharges and contain eight sources capable of delivering 20MW of power. The delivered power is typically limited to 3.5 s per source to protect beam-line components, while a DIII-D plasma discharge usually exceeds 5 s. Implemented as a hardware interlock within the neutral beam power supplies, the NBOTL limits the beam injection time. With a continuing emphasis on modulated beam injections, the NBOTL guards against command faults and allows the beam injection to be safely spread over a longer plasma discharge time. The NBOTL design is an example of incorporating modern circuit design techniques (CPLD) within an established format (CAMAC). The CPLD is the heart of the NBOTL and contains 90% of the circuitry, including a loadable, 1 MHz, 28 bit, BCD count down timer, buffers, and CAMAC communication circuitry. This paper discusses the circuit design and implementation. Of particular interest is the melding of flexible modern programmable logic devices with the CAMAC format.

Baggest, D.S.; Broesch, J.D.; Phillips, J.C.

1999-11-01

309

Windshield-wiper loosening: a complication of in situ screw fixation of slipped capital femoral epiphysis.  

PubMed

A retrospective review of patients treated for slipped capital femoral epiphysis (SCFE) by in situ screw fixation with a cannulated titanium screw was performed. Of the 18 hips with at least 1-year follow-up, windshield-wiper loosening of the cannulated screw in the femoral head had occurred in three. In all three cases, the screw had been left protruding > 1.5 cm from the anterolateral cortex of the femur. We postulate that with hip motion the protruding screw is toggled by the anterolateral soft tissues, causing a windshield-wiper effect in the femoral head, leading to eventual screw loosening. We believe that leaving the screw protruding from the fascia lata is a potential source of screw loosening by the windshield-wiper mechanism and now routinely place the screw head within 1.5 cm of the anterolateral cortex of the femur. PMID:8376561

Maletis, G B; Bassett, G S

1993-01-01

310

Prediction of Deformity Correction by Pedicle Screw Instrumentation in Thoracolumbar Scoliosis Surgery  

NASA Astrophysics Data System (ADS)

In segmental pedicle screw instrumentation, the relationship between the combinations of pedicle screw placements and the degree of deformity correction was investigated with a three-dimensional rigid body and spring model. The virtual thoracolumbar scoliosis (Cobb’s angle of 47 deg.) was corrected using six different combinations of pedicle-screw placements. As a result, better correction in the axial rotation was obtained with the pedicle screws placed at or close to the apical vertebra than with the screws placed close to the end vertebrae, while the correction in the frontal plane was better with the screws close to the end vertebrae than with those close to the apical vertebra. Additionally, two screws placed in the convex side above and below the apical vertebra provided better correction than two screws placed in the concave side. Effective deformity corrections of scoliosis were obtained with the proper combinations of pedicle screw placements.

Kiriyama, Yoshimori; Yamazaki, Nobutoshi; Nagura, Takeo; Matsumoto, Morio; Chiba, Kazuhiro; Toyama, Yoshiaki

311

Self-tapping versus standard tapped titanium screw fixation in the upper extremity.  

PubMed

Most screws used in fracture fixation necessitate a separate step for tapping of the screw hole. Titanium screw systems have been developed in which the screws can be inserted directly after a drill hole is made. These self-tapping screws thereby eliminate an operative step. A retrospective study was conducted that evaluated all wrist and hand procedures performed between January 1992 and December 1994 by 1 surgeon using screw fixation. The results of 39 cases treated with standard tapped titanium screws were compared with 28 cases treated with self-tapping titanium screws. Nearly identical union and complication rates were obtained in each group. Comparable results can be obtained with self-tapping screw fixation, which limits the number of instruments needed, eliminates an operative step, and thereby may diminish operative risk and shorten operative time. PMID:9556274

Bickley, M B; Hanel, D P

1998-03-01

312

A processing method for orthodontic mini-screws reuse  

PubMed Central

Background: The possibility of mini-screws reuse would reduce treatment cost. The aim of this study is to introduce a new method (application of phosphoric acid 37% for 10 minutes followed by sodium hypochlorite 5.25% for 30 minutes) for cleansing of mini-screws and assessing the efficacy of this method. The effects of this processing on the insertion, removal, and fracture torques of mini-screws were evaluated. Materials and Methods: This experimental study was done in two parts. In part I the amount of calcium ion on mini-screws surfaces as an index of tissue remnants was assessed. In part II of this study, the effects of previous use, processing method, and resterilization on the insertion, removal, and fracture torques of mini-screws were assessed. Each part of this study had 3 groups; non-processed used (NP), processed used (P), and as-received (C). Each group had 16 samples in part I and 20 samples. Non parametric statistical tests were used in part I and one way ANOVA in part II. Results: The mean amount of calcium ion in groups non-processed (NP1), processed (P1), and control (C1) were 4.7, 0.43, and 0.02 ppm, respectively. The amount of calcium ion in group NP1 was significantly greater than in the other groups (P = 0.000), but the difference between groups P1 and C1 was not significant (P = 0.087). The mean insertion torque of group NP2 was lower than that of other groups (P < 0.05) but P2 and C2 did not have significant differences (P = 0.988). The mean of removal and fracture torque did not have significant differences among all groups. Conclusion: Cleaning of used mini-screws with phosphoric acid 37% (10 minutes) and sodium hypochlorite 5.25% (30 minutes) reduces tissue remnants to the level of as-received mini-screws. So it can be suggested as a processing method of used mini-screws. Previous insertion of mini-screws into the bone and above-mentioned processing method and resterilization with autoclave had no adverse effects on insertion, removal, and fracture torque values as mechanical properties indices.

Noorollahian, Saeed; Alavi, Shiva; Monirifard, Mohammad

2012-01-01

313

[Observations on before and after employ of screw of implant denture with SEM].  

PubMed

The loss of screw is one of the clinic complication in MDIC implant denture cases. The purpose of this study is to find the cause of loss of screw. The authors has studied MDIC implant denture with SEM before and after employ of the screw and found that the causes of screw loss were crevice corrosion and friction pressure. Crevice corrosion may promote the loss of screw. Base the above condition, it is necessary to select Ti-alloy screw and associat with anticorrosive measure in MDIC implant denture construction. PMID:10677963

Song, Y; Xu, J; Ma, X

1997-03-01

314

Planning and insertion of pedicle screws with computer assistance.  

PubMed

Transpedicular screw fixation relies on thorough knowledge of the pedicular anatomy and a reliable intraoperative technique. To enhance the safety and accuracy of screw insertion, computer-assisted systems have been introduced. Our in vitro study investigated the potential benefits of such a system for the preoperative planning and the intraoperative visualization. In part 1, the potentially possible range of screw paths (trajectories) through lumbar pedicles was analyzed. In part 2, the accuracy of actual pedicle-hole preparation with and without preoperative planning was assessed. It was shown that, especially in the lower lumbar regions, the possible range of trajectories is considerable, with inclinations of < or = 40 degrees in the transverse plane and a range of angulation in the sagittal plane of > 20 degrees. The computer assistance in preparation of 100 pedicle holes resulted in cortex perforation in only one case. Computer assistance therefore may be used as a valuable tool to minimize the risks of transpedicular screw insertion. It furthermore may assist in determining the desired screw orientation and length and transform this planning into the intraoperative pedicle-hole preparation. PMID:9113610

Berlemann, U; Monin, D; Arm, E; Nolte, L P; Ozdoba, C

1997-04-01

315

Modern posterior screw techniques in the pediatric cervical spine  

PubMed Central

Treatment of children with cervical spine disorders requiring fusion is a challenging endeavor for a variety of reasons. The size of the patients, the corresponding abnormal bony anatomy, the inherent ligamentous laxity of children, and the relative rarity of the disorders all play a part in difficulty of treatment. The benefits of modern posterior cervical instrumentation in children, defined as rigid screw-rod systems, have been shown to be many including: improved arthrodesis rates, diminished times in halo-vest immobilization, and improved reduction of deformities. The anatomy of children and the corresponding pathology seen frequently is at the upper cervical spine and craniocervical junction given the relatively large head size of children and the horizontal facets at these regions predisposing them to instability or deformity. Posterior screw fixation, while challenging, allows for a rigid base to allow for fusion in these upper cervical areas which are predisposed to pseudarthrosis with non-rigid fixation. A thorough understanding of the anatomy of the cervical spine, the morphology of the cervical spine, and the available screw options is paramount for placing posterior cervical screws in children. The purpose of this review is to discuss both the anatomical and clinical descriptions related to posterior screw placement in the cervical spine in children.

Hedequist, Daniel J

2014-01-01

316

Design optimization of the hip nail-plate-screws implant.  

PubMed

This paper is aimed at determining the number of screws and the dimensions of the appliance components of a hip nail-plate screw implant such that their sizes are a minimum (i.e. the implant weight is minimum), without the stresses in the appliance components as well as in the bone shaft exceeding the allowable limits. The implant-bone structure is idealized as a hybrid frame, composed of appliance components and the supporting femur bone elements, which act integrally to support the maximal load (during the gait cycle) at the hip joint. For various configurations of the implant, entailing different numbers of screws, the optimization technique is employed to determine the size of the members (nail, plate and screws) for a lightweight design. Implant configurations are analyzed for two, three, four and five nail configurations. The analysis of the hybrid (implant femur) frame, during each integrative object function and design parameter evaluation, is done by the Finite Element Method. The optimization problem is solved by the sequential unconstrained minimization technique (with the introduction of interior penalty function terms). It is found, from the results of analyses of the four hybrid frames, that the appliance frame, with two screws, yields the minimum-weight structurally safe design. PMID:8925648

Elkholy, A H

1995-12-01

317

Management of odontoid fractures with percutaneous anterior odontoid screw fixation  

PubMed Central

Minimally invasive techniques have revolutionized the management of a variety of spinal disorders. The authors of this study describe a new instrument and a percutaneous technique for anterior odontoid screw fixation, and evaluate its safety and efficacy in the treatment of patients with odontoid fractures. Ten patients (6 males and 4 females) with odontoid fractures were treated by percutaneous anterior odontoid screw fixation under fluoroscopic guidance from March 2000 to May 2002. Their mean age at presentation was 37.2 years (with a range from 21 to 55 years). Six cases were Type II and four were Type III classified by the Anderson and D’Alonzo system. The operation was successfully completed without technical difficulties, and without any soft tissue complications such as esophageal injury. No neurological deterioration occurred. Satisfactory results were achieved in all patients and all of the screws were in good placement. After a mean follow-up of 15.7 months (range 10–25 months), radiographic fusion was documented for 9 of 10 patients (90%). Neither clinical symptoms nor screw loosening or breakage occurred. Our preliminary clinical results suggest that the percutaneous anterior odontoid screw fixation procedure using a new instrument and fluoroscopy is technically feasible, safe, useful, and minimally invasive.

Wang, Xiang-Yang; Xu, Hua-Zi; Lin, Yan; Huang, Qi-Shan; Mao, Fang-Min; Ni, Wen-Fei; Wang, Sheng; Dai, Li-Yang

2007-01-01

318

Screw dislocations in GaN grown by different methods  

SciTech Connect

A study of screw dislocations in Hydride-Vapor-Phase-Epitaxy (HVPE) template and Molecular-Beam-Epitaxy (MBE) over-layers was performed using Transmission Electron Microscopy (TEM) in plan-view and in cross-section. It was observed that screw dislocations in the HVPE layers were decorated by small voids arranged along the screw axis. However, no voids were observed along screw dislocations in MBE overlayers. This was true both for MBE samples grown under Ga-lean and Ga-rich conditions. Dislocation core structures have been studied in these samples in the plan-view configuration. These experiments were supported by image simulation using the most recent models. A direct reconstruction of the phase and amplitude of the scattered electron wave from a focal series of high-resolution images was applied. It was shown that the core structures of screw dislocations in the studied materials were filled. The filed dislocation cores in an MBE samples were stoichiometric. However, in HVPE materials, single atomic columns show substantial differences in intensities and might indicate the possibility of higher Ga concentration in the core than in the matrix. A much lower intensity of the atomic column at the tip of the void was observed. This might suggest presence of lighter elements, such as oxygen, responsible for their formation.

Liliental-Weber, Z.; Zakharov, D.; Jasinski, J.; O'Keefe, M.A.; Morkoc, H.

2003-05-27

319

Modern posterior screw techniques in the pediatric cervical spine.  

PubMed

Treatment of children with cervical spine disorders requiring fusion is a challenging endeavor for a variety of reasons. The size of the patients, the corresponding abnormal bony anatomy, the inherent ligamentous laxity of children, and the relative rarity of the disorders all play a part in difficulty of treatment. The benefits of modern posterior cervical instrumentation in children, defined as rigid screw-rod systems, have been shown to be many including: improved arthrodesis rates, diminished times in halo-vest immobilization, and improved reduction of deformities. The anatomy of children and the corresponding pathology seen frequently is at the upper cervical spine and craniocervical junction given the relatively large head size of children and the horizontal facets at these regions predisposing them to instability or deformity. Posterior screw fixation, while challenging, allows for a rigid base to allow for fusion in these upper cervical areas which are predisposed to pseudarthrosis with non-rigid fixation. A thorough understanding of the anatomy of the cervical spine, the morphology of the cervical spine, and the available screw options is paramount for placing posterior cervical screws in children. The purpose of this review is to discuss both the anatomical and clinical descriptions related to posterior screw placement in the cervical spine in children. PMID:24829871

Hedequist, Daniel J

2014-04-18

320

Optically driven Archimedes micro-screws for micropump application.  

PubMed

Archimedes micro-screws have been fabricated by three-dimensional two-photon polymerization using a Nd:YAG Q-switched microchip laser at 532nm. Due to their small sizes they can be easily manipulated, and made to rotate using low power optical tweezers. Rotation rates up to 40 Hz are obtained with a laser power of 200 mW, i.e. 0.2 Hz/mW. A photo-driven micropump action in a microfluidic channel is demonstrated with a non-optimized flow rate of 6 pL/min. The optofluidic properties of such type of Archimedes micro-screws are quantitatively described by the conservation of momentum that occurs when the laser photons are reflected on the helical micro-screw surface. PMID:21643076

Lin, Chih-Lang; Vitrant, Guy; Bouriau, Michel; Casalegno, Roger; Baldeck, Patrice L

2011-04-25

321

[Management of proximal scaphoid bone pseudarthroses and fractures with the mini-Herbert screw via a dorsal approach].  

PubMed

32 patients, aged 16 to 49 years, were treated by osteosynthesis using the Herbert mini screw. The indications were five fractures (type B3, Herbert classification), two delayed unions (type C) and 25 nonunions (type D1 to D3, Filan and Herbert classification). Six patients received no bone grafts, 19 received cancellous bone graft from the radius. An interpositional iliac crest bone graft was used in four, and a vascularized bone graft from the distal radius in three cases respectively. The average postoperative immobilisation in a forearm splint was nine weeks. 26 patients could be recruited for clinical follow-up at an average of 14.5 months. The radiological results were assessed in 30 cases (94%). Bony consolidation was achieved in 26 cases (100% of the fractures, 84% of the nonunions). In three cases a loosening of the screw, and in three further cases a dislocation into the radiocarpal joint were observed. A humpback deformity was present in four cases. Three patients showed a persisting nonunion, one patient a fibrous union. Early degenerative changes of the radiocarpal joint were observed in six cases. The clinical follow up examination showed an average grip strength of 91% (JAMAR II), 94% for the three finger, and 95% for the pinch grip compared to the contralateral side. The mean postoperative pain score on the visual analog scale was one for resting conditions, eleven for motion and 33 under stress. The range of motion was 79% of the opposite side for extension/flexion and 83% for radial/ulnar deviation. The average DASH-score reached 15 points. The Herbert mini screw has proven to be a reliable implant for reconstruction of proximal pole fractures and nonunions of the scaphoid. PMID:11572122

Küntscher, M; Tränkle, M; Sauerbier, M; Germann, G; Bickert, B

2001-09-01

322

Comparative study on stress distribution around internal tapered connection implants according to fit of cement- and screw-retained prostheses  

PubMed Central

PURPOSE The aim of this study was to compare the passivity of implant superstructures by assessing the strain development around the internal tapered connection implants with strain gauges. MATERIALS AND METHODS A polyurethane resin block in which two implants were embedded served as a measurement model. Two groups of implant restorations utilized cement-retained design and internal surface of the first group was adjusted until premature contact between the restoration and the abutment completely disappeared. In the second group, only nodules detectable to the naked eye were removed. The third group employed screw-retained design and specimens were generated by computer-aided design/computer-aided manufacturing system (n=10). Four strain gauges were fixed on the measurement model mesially and distally to the implants. The strains developed in each strain gauge were recorded during fixation of specimens. To compare the difference among groups, repeated measures 2-factor analysis was performed at a level of significance of ?=.05. RESULTS The absolute strain values were measured to analyze the magnitude of strain. The mean absolute strain value ranged from 29.53 to 412.94 µm/m at the different strain gauge locations. According to the result of overall comparison, the cement-retained prosthesis groups exhibited significant difference. No significant difference was detected between milled screw-retained prostheses group and cement-retained prosthesis groups. CONCLUSION Within the limitations of the study, it was concluded that the cement-retained designs do not always exhibit lower levels of stress than screw-retained designs. The internal adjustment of a cement-retained implant restoration is essential to achieve passive fit.

Lee, Mi-Young; Heo, Seong-Joo; Park, Eun-Jin

2013-01-01

323

Unilateral molar distalization: a nonextraction therapy.  

PubMed

In the recent years, nonextraction treatment approaches and noncompliance therapies have become more popular in the correction of space discrepancies. One of the conventional approaches for space gaining in the arches without patient compliance is done by using certain extra oral appliances or intraoral appliance. The greatest advantage of certain appliances like fixed functional and molar distalization appliances is that they minimize the dependence on patient cooperation. Molar distalization appliances like pendulum appliance which distalizes the molar rapidly without the need of head gear can be used in patients as a unilateral space gaining procedure due to buccal segment crowding. PMID:23320203

Prasad, M Bhanu; Sreevalli, S

2012-01-01

324

Unilateral Molar Distalization: A Nonextraction Therapy  

PubMed Central

In the recent years, nonextraction treatment approaches and noncompliance therapies have become more popular in the correction of space discrepancies. One of the conventional approaches for space gaining in the arches without patient compliance is done by using certain extra oral appliances or intraoral appliance. The greatest advantage of certain appliances like fixed functional and molar distalization appliances is that they minimize the dependence on patient cooperation. Molar distalization appliances like pendulum appliance which distalizes the molar rapidly without the need of head gear can be used in patients as a unilateral space gaining procedure due to buccal segment crowding.

Prasad, M. Bhanu; Sreevalli, S.

2012-01-01

325

Laparoscopic radical distal gastrectomy for ca stomach.  

PubMed

Gastric cancer remains an important cause of cancer-related deaths and a complete margin-negative (R0) resection remains the only potentially curative treatment for gastric adenocarcinoma. We report a case of carcinoma of distal stomach in a 48-year-old male patient who was diagnosed on UGI endoscopy and CT scan. He had symptoms suggestive of gastric outlet obstruction due to stenosing lesion. He was successfully treated with laparoscopic distal gastrectomy with D2 lymphadenectomy. Laparoscopic distal gastrectomy is justified by its feasibility, early recovery, oncological safety, and improved quality of life in cancer stomach. PMID:24426619

Deo, Sadhana V; Puntambekar, Shailesh P

2013-06-01

326

Semiconstrained Distal Radioulnar Joint Prosthesis  

PubMed Central

Distal radioulnar joint (DRUJ) problems can occur as a result of joint instability, abutment, or incongruity. The DRUJ is a weight-bearing joint; the ulnar head is frequently excised either totally or partially, and in some cases it is fused, because of degenerative, rheumatoid, or posttraumatic arthritis. Articles about these procedures report the ability to pronate and supinate, but they rarely discuss grip strength, and even less do they address lifting capacity. We report the long term results of the first 35 patients who underwent total DRUJ arthroplasty with the Aptis DRUJ prosthesis after 5 years follow-up. Surgical indications were all causes of dysfunctional DRUJ (degenerative, posttraumatic, autoimmune, congenital). We recorded data for patient demographics, range of motion (ROM), strength, and lifting capacity of the operated and of the nonoperated extremity. Pain and functional assessments were also recorded. The Aptis DRUJ prosthesis, a bipolar self-stabilizing DRUJ endoprosthesis that restores forearm function, consists of a semiconstained and modular implant designed to replace the function of the ulnar head, the sigmoid notch of the radius, and the triangular fibrocartilage ligaments. The surgical technique is presented in detail. The majority of the patients regained adequate ROM and improved their strength and lifting capacity to the operated side. Pain and activities of daily living were improved. Twelve patients experienced complications, most commonly being extensor carpi ulnaris (ECU) tendinitis, ectopic bone formation, bone resorption with stem loosening, low-grade infection, and need for ball replacement. The Aptis total DRUJ replacement prosthesis is an alternative to salvage procedures that enables a full range of motion as well as the ability to grip and lift weights encountered in daily living activities.

Savvidou, Christiana; Murphy, Erin; Mailhot, Emilie; Jacob, Shushan; Scheker, Luis R.

2013-01-01

327

Single crystal alumina for dental implants and bone screws.  

PubMed

When ground to a suitable form, flexural strength of single crystal alumina (Al2O3) decreases to as low as one third the strength of the intact crystal. This flexural strength decrease is, however, recovered by chemical etching at a high temperature to eliminate surface defects caused by grinding. By using this strength recovery treatment, various types of single crystal implants with fine structure were able to be designed. Four kinds of single crystal bone screws and single crystal dental implants of screw and anchor type were designed. Flexural strength and impact strength of the implants were measured. PMID:7349666

Kawahara, H; Hirabayashi, M; Shikita, T

1980-09-01

328

Virtual estimates of fastening strength for pedicle screw implantation procedures  

NASA Astrophysics Data System (ADS)

Traditional 2D images provide limited use for accurate planning of spine interventions, mainly due to the complex 3D anatomy of the spine and close proximity of nerve bundles and vascular structures that must be avoided during the procedure. Our previously developed clinician-friendly platform for spine surgery planning takes advantage of 3D pre-operative images, to enable oblique reformatting and 3D rendering of individual or multiple vertebrae, interactive templating, and placement of virtual pedicle implants. Here we extend the capabilities of the planning platform and demonstrate how the virtual templating approach not only assists with the selection of the optimal implant size and trajectory, but can also be augmented to provide surrogate estimates of the fastening strength of the implanted pedicle screws based on implant dimension and bone mineral density of the displaced bone substrate. According to the failure theories, each screw withstands a maximum holding power that is directly proportional to the screw diameter (D), the length of the in-bone segm,ent of the screw (L), and the density (i.e., bone mineral density) of the pedicle body. In this application, voxel intensity is used as a surrogate measure of the bone mineral density (BMD) of the pedicle body segment displaced by the screw. We conducted an initial assessment of the developed platform using retrospective pre- and post-operative clinical 3D CT data from four patients who underwent spine surgery, consisting of a total of 26 pedicle screws implanted in the lumbar spine. The Fastening Strength of the planned implants was directly assessed by estimating the intensity - area product across the pedicle volume displaced by the virtually implanted screw. For post-operative assessment, each vertebra was registered to its homologous counterpart in the pre-operative image using an intensity-based rigid registration followed by manual adjustment. Following registration, the Fastening Strength was computed for each displaced bone segment. According to our preliminary clinical study, a comparison between Fastening Strength, displaced bone volume and mean voxel intensity showed similar results (p < 0.1) between the virtually templated plans and the post-operative outcome following the traditional clinical approach. This study has demonstrated the feasibility of the platform in providing estimates the pedicle screw fastening strength via virtual implantation, given the intrinsic vertebral geometry and bone mineral density, enabling the selection of the optimal implant dimension adn trajectory for improved strength.

Linte, Cristian A.; Camp, Jon J.; Augustine, Kurt E.; Huddleston, Paul M.; Robb, Richard A.; Holmes, David R.

2014-03-01

329

Herbert bone screw fixation of the Austin bunionectomy.  

PubMed

This manuscript represents an alternative method of fixation for the Austin bunionectomy using the Herbert bone screw. A description of the modified Austin bunionectomy and fixation utilizing this system is presented. A discussion of potential and encountered complications is included. Two hundred and four osteotomies were fixated with the Herbert bone screw in 182 patients, with follow-up ranging from 6 months to 3 years. Early range of motion, rigid internal fixation with compression, and the elimination of pin tracks are the advantages of this method. PMID:3446706

Quinn, M R; DiStazio, J J; Kruljac, S J

1987-01-01

330

Optical conductivity of semiconductor crystals with a screw dislocation  

NASA Astrophysics Data System (ADS)

We study ac electronic transport in semiconductor crystals with a screw dislocation. The screw dislocation in the crystal results in an effective potential field that has a pronounced effect on the quantum mechanical electronic transport of the system. Alternating current conductivity at a frequency around 100 GHz has been calculated, showing upward shift in the peak position with increasing the Fermi energy. The result is in contrast to the persistency in the peak position observed in a dislocation-free crystal penetrated by magnetic flux, despite the apparent similarity between the two crystalline systems.

Taira, Hisao; Shima, Hiroyuki

2014-01-01

331

Experimental Results of Single Screw Mechanical Tests. A Follow-Up to SAND2005-6036.  

National Technical Information Service (NTIS)

The work reported here was conducted to address issues raised regarding mechanical testing of attachment screws described in SAND2005-6036, as well as to increase the understanding of screw behavior through additional testing. Efforts were made to evaluat...

J. S. Korellis K. L. Lee S. Lee X. McFadden

2006-01-01

332

Intraoperative C-arm CT imaging in angular stable plate osteosynthesis of distal radius fractures.  

PubMed

The purpose of this study was to analyze the practicability and benefit of intraoperative C-arm computed tomography (CT) imaging in volar plate osteosynthesis of unstable distal radius fractures. During a 1 year period, intraoperative three dimensional (3D) imaging with the ARCADIS Orbic 3D was performed in addition to standard fluoroscopy in 51 cases. The volar angular stable plate oesteosyntheses were analyzed intraoperatively and, if necessary, improved immediately. The duration of the scan and radiation exposure dose were measured. On average, performance of the scan and analysis of the CT dataset took 6.7 minutes. In 31.3% of the surgeries a misplacement of screws was detected and correction was done immediately. C-arm CT imaging can easily be integrated in the normal course of surgery. As a complement to the standard 2D-fluoroscopy, the C-arm CT is a useful tool to evaluate the quality of osteosynthesis. PMID:23390154

Mehling, I; Rittstieg, P; Mehling, A P; Küchle, R; Müller, L P; Rommens, P M

2013-09-01

333

Increased initial cement-bone interlock correlates with reduced total knee arthroplasty micro-motion following in vivo service.  

PubMed

Aseptic loosening of cemented tibial components in total knee arthroplasty (TKA) has been related to inadequate cement penetration into the trabecular bone bed during implantation. Recent postmortem retrieval work has also shown there is loss of interlock between cement and bone by resorption of trabeculae at the interface. The goal of this study was to determine if TKAs with more initial interlock between cement and bone would maintain more interlock with in vivo service (in the face of resorbing trabeculae) and have less micro-motion at the cement-bone interface. The initial (created at surgery) and current (after in vivo service) cement-bone interlock morphologies of sagittal implant sections from postmortem retrieved tibial tray constructs were measured. The implant sections were then functionally loaded in compression and the micro-motion across the cement-bone interface was quantified. Implant sections with less initial interdigitation between cement and bone and more time in service had less current cement-bone interdigitation (r(2)=0.86, p=0.0002). Implant sections with greater initial interdigitation also had less micro-motion after in vivo service (r(2)=0.36, p=0.0062). This work provides direct evidence that greater initial interlock between cement and bone in tibial components of TKA results in more stable constructs with less micro-motion with in vivo service. PMID:24795171

Miller, Mark A; Terbush, Matthew J; Goodheart, Jacklyn R; Izant, Timothy H; Mann, Kenneth A

2014-07-18

334

[Biomechanical studies of 9 tibial interlocking nails in a bone-implant unit].  

PubMed

Various different interlocking intramedullary nail designs are now available for the tibia the designs resulting from a different approaches to achieving stability for fracture fixation. During recent years small-diameter unreamed interlocking nails have been developed. So far there are no data on stiffness of different nail designs that can justify the use of certain nail types. We compared different nail types in the bone-implant complex (BIC) with reference to stiffness under axial load, bending and torsion of the BIC. We simulated comminuted mid-shaft fractures by a 2-cm defect osteotomy in paired human cadaver tibiae. We fixed each tibia with one of nine different interlocking nails (AO Unreamed Tibial Nail 9 mm [UTN9], AO Unreamed Tibial Nail 8 mm [UTN8], Russell & Taylor Delta Tibial Nail 9 mm [RTD], Russell & Taylor Reconstruction Tibial Nail 11 mm [RTR], Brooker & Wills Nail 11 mm [B-W], Grosse & Kempf Tibial Nail 11 mm [G-K], AO Universal Tibial Nail 11 mm [AOU], Klemm & Schellmann Tibial Nail 11 mm [K-S], Börner & Mattheck Tibial Nail 11 mm [B-M]) according to the manufacturers' recommendations. Each BIC was tested mechanically using a Zwick universal testing machine. Torque testing was performed with a maximum moment of 5 Nm in both directions. Maximum axial load was 1100 N. Four-point bending was done up to a moment of 66 Nm. For each implant bending and torque stiffness of the nail were calculated and compared with the test results obtained in the cadaver study. A P-value less than 0.05 (least significance difference test, ANOVA) was considered significant.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7817197

Schandelmaier, P; Krettek, C; Tscherne, H

1994-11-01

335

Estimating Driver Risk Using Alcohol Biomarkers, Interlock BAC Tests and Psychometric Assessments: Initial Descriptives  

PubMed Central

Aim To identify alcohol biomarker and psychometric measures that relate to drivers’ blood alcohol concentration (BAC) patterns from ignition interlock devices (IIDs). Design, Setting, Participants, Measurements In Alberta, Canada, 534 drivers, convicted of driving under the influence of alcohol (DUI), installed IIDs and agreed to participate in a research study. IID BAC tests are an established proxy for predicting future DUI convictions. Three risk groups were defined by rates of failed BAC tests. Program entry and followup blood samples (n=302, 171) were used to measure phosphatidyl ethanol (PETH), carbohydrate deficient transferrin (%CDT), gamma glutamyltransferase (GGT) and other biomarkers. Program entry urine (n=130) was analyzed for ethyl glucuronide (ETG) and ethyl sulfate (ETS). Entry hair samples were tested for fatty acid ethyl esters (FAEE) (n=92) and ETG (n=146). Psychometric measures included the DSM-4 Diagnostic Interview Schedule Alcohol Module, Alcohol Use Disorders Identification Test (AUDIT), the Timeline Followback (TLFB), the Drinker Inventory of Consequences (DRINC), and the Temptation and Restraint Inventory (TRI). Findings Except for FAEE, all alcohol biomarkers were significantly related to the interlock BAC test profiles; higher marker levels predicted higher rates of interlock BAC test failures. PETH, the strongest with an overall ANOVA F ratio of 35.5, had significant correlations with all nine of the other alcohol biomarkers and with 16 of 19 psychometric variables. Urine ETG and ETS were strongly correlated with the IID BAC tests. Conclusions The findings suggest several alcohol biomarkers and assessments could play an important role in the prediction and control of driver alcohol risk when relicensing.

Marques, Paul; Tippetts, Scott; Allen, John; Javors, Martin; Alling, Christer; Yegles, Michel; Pragst, Fritz; Wurst, Friedrich

2009-01-01

336

Biomechanical and histological evaluation of an expandable pedicle screw in osteoporotic spine in sheep  

Microsoft Academic Search

Transpedicular fixation can be challenging in the osteoporotic spine as reduced bone mineral density compromises the mechanical\\u000a stability of the pedicle screw. Here, we sought to investigate the biomechanical and histological properties of stabilization\\u000a of expandable pedicle screw (EPS) in the osteoporotic spine in sheep. EPSs and standard pedicle screws, SINO screws, were\\u000a inserted on the vertebral bodies in four

Shiyong Wan; Wei Lei; Zixiang Wu; Da Liu; Mingxuan Gao; Suochao Fu

2010-01-01

337

Biomechanical and Histological Evaluation of Roughened Surface Titanium Screws Fabricated by Electron Beam Melting  

PubMed Central

Background Various fabrication methods are used to improve the stability and osseointegration of screws within the host bone. The aim of this study was to investigate whether roughened surface titanium screws fabricated by electron beam melting can provide better stability and osseointegration as compared with smooth titanium screws in sheep cervical vertebrae. Methods Roughened surface titanium screws, fabricated by electron beam melting, and conventional smooth surface titanium screws were implanted into sheep for 6 or 12 weeks (groups A and B, respectively). Bone ingrowth and implant stability were assessed with three-dimensional imaging and reconstruction, as well as histological and biomechanical tests. Results No screws in either group showed signs of loosening. Fibrous tissue formation could be seen around the screws at 6 weeks, which was replaced with bone at 12 weeks. Bone volume/total volume, bone surface area/bone volume, and the trabecular number were significantly higher for a define region of interest surrounding the roughened screws than that surrounding the smooth screws at 12 weeks. Indeed, for roughened screws, trabecular number was significantly higher at 12 weeks than at 6 weeks. On mechanical testing, the maximum pullout strength was significantly higher at 12 weeks than at 6 weeks, as expected; however, no significant differences were found between smooth and roughened screws at either time point. The maximum torque to extract the roughened screws was higher than that required for the smooth screws. Conclusions Electron beam melting is a simple and effective method for producing a roughened surface on titanium screws. After 12 weeks, roughened titanium screws demonstrated a high degree of osseointegration and increased torsional resistance to extraction over smooth titanium screws.

Yang, Jun; Cai, Hong; Lv, Jia; Zhang, Ke; Leng, Huijie; Wang, Zhiguo; Liu, Zhongjun

2014-01-01

338

Axial and Angled Pullout Strength of Bone Screws in Normal and Osteoporotic Bone Material  

Microsoft Academic Search

Orthopedic surgery often involves the use of bone screws to stabilize fractures. Screw fixation can be extremely difficult\\u000a in osteoporotic (OP) bone because of its compromised strength. Pullout strength is commonly used to measure screw fixation\\u000a strength. In this study, axial and angled screw pullouts (ranging from 0° to 40°) were performed on 0.09 g.cm-3, 0.16 g.cm-3 and 0.32 g.cm-3

P. S. D. Patel; D. E. T. Shepherd; D. W. L. Hukins

339

Ground-state kinetics of bistable redox-active donor-acceptor mechanically interlocked molecules.  

PubMed

The ability to design and confer control over the kinetics of theprocesses involved in the mechanisms of artificial molecular machines is at the heart of the challenge to create ones that can carry out useful work on their environment, just as Nature is wont to do. As one of the more promising forerunners of prototypical artificial molecular machines, chemists have developed bistable redox-active donor-acceptor mechanically interlocked molecules (MIMs) over the past couple of decades. These bistable MIMs generally come in the form of [2]rotaxanes, molecular compounds that constitute a ring mechanically interlocked around a dumbbell-shaped component, or [2]catenanes, which are composed of two mechanically interlocked rings. As a result of their interlocked nature, bistable MIMs possess the inherent propensity to express controllable intramolecular, large-amplitude, and reversible motions in response to redox stimuli. In this Account, we rationalize the kinetic behavior in the ground state for a large assortment of these types of bistable MIMs, including both rotaxanes and catenanes. These structures have proven useful in a variety of applications ranging from drug delivery to molecular electronic devices. These bistable donor-acceptor MIMs can switch between two different isomeric states. The favored isomer, known as the ground-state co-conformation (GSCC) is in equilibrium with the less favored metastable state co-conformation (MSCC). The forward (kf) and backward (kb) rate constants associated with this ground-state equilibrium are intimately connected to each other through the ground-state distribution constant, KGS. Knowing the rate constants that govern the kinetics and bring about the equilibration between the MSCC and GSCC, allows researchers to understand the operation of these bistable MIMs in a device setting and apply them toward the construction of artificial molecular machines. The three biggest influences on the ground-state rate constants arise from (i) ground-state effects, the energy required to breakup the noncovalent bonding interactions that stabilize either the GSCC or MSCC, (ii) spacer effects, where the structures overcome additional barriers, either steric or electrostatic or both, en route from one co-conformation to the other, and (iii) the physical environment of the bistable MIMs. By managing all three of these effects, chemists can vary these rate constants over many orders of magnitude. We also discuss progress toward achieving mechanostereoselective motion, a key principle in the design and realization of artificial molecular machines capable of doing work at the molecular level, by the strategic implementation of free energy barriers to intramolecular motion. PMID:24341283

Fahrenbach, Albert C; Bruns, Carson J; Li, Hao; Trabolsi, Ali; Coskun, Ali; Stoddart, J Fraser

2014-02-18

340

Successful Transcatheter Embolization of Penetrating Aortic Ulcer Using Interlocking Detachable Coils  

SciTech Connect

A 54-year-old man with persistent chest pain was hospitalized for hypertension and DeBakey type IIIb aortic dissection. The false lumen of the dissection was almost completely thrombosed; however, a penetrating atherosclerotic ulcer (PAU) was observed 5 weeks later. At that time, we successfully embolized the PAU with a microcatheter and interlocking detachable coils (IDCs). The patient is well with no episodes of relapse in 20 months of follow-up. This case suggests the utility of the microcatheter and IDC system as an alternative to surgery.

Hama, Yukihiro; Kaji, Tatsumi; Iwasaki, Yoshie [Department of Radiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042 (Japan); Hinokiyama, Kazuhiro; Shimizu, Masafumi [Department of Surgery II, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042 (Japan); Kusano, Shoichi [Department of Radiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042 (Japan)

2000-09-15

341

Distal Embolic Protection for Renal Arterial Interventions  

Microsoft Academic Search

Distal or embolic protection has intuitive appeal for its potential to prevent embolization of materials generated during\\u000a interventional procedures. Distal protection devices (DPDs) have been most widely used in the coronary and carotid vascular\\u000a beds, where they have demonstrated the ability to trap embolic materials and, in some cases, to reduce complications. Given\\u000a the frequency of chronic kidney disease in

Gregory J. Dubel; Timothy P. Murphy

2008-01-01

342

Wrist fractures in the athlete. Distal radius and carpal fractures.  

PubMed

The primary prerequisites for optimal management of the athlete's fractured wrist are prompt diagnosis, anatomic and stable reduction, effective immobilization until healing is thorough, and comprehensive rehabilitation of the injured parts. Fulfillment of these fundamental criteria consistently leads to a highly favorable outcome with minimal risk of re-injury. In contrast, a compromise of these principles, especially for the sake of a speedy return to sports, invariably results in suboptimal recovery and, not infrequently, a permanent loss of skills. The exceptions to the cardinal rule that successful treatment of wrist fractures requires precise restoration of anatomic relationships are specific: displaced hamate hook fractures, displaced trapezial ridge fractures, and comminuted pisiform fractures. In such instances, successful union essentially is precluded, and early excision of the displaced fragments is the logical means of facilitating an uncomplicated recovery. For the more complex fractures requiring stabilization, continual refinements in methods of fixation are considerably diminishing fracture morbidity. The availability of small screws that provide rigid fixation of the carpus is, with increasing consistency, promoting accelerated union and rapid rehabilitation. Well-conceived combinations of low-profile, mechanically efficient external fixators and precisely used Kirschner wires achieve highly secure fracture stability for the distal radius that similarly enhances recovery with a minimum of complications. Improvements in both design and application of internal and external fixation techniques undoubtedly constitute a major advance in the management of wrist fractures among athletes. For some athletes, the return to competition can be safely expedited by the use of custom-fit protective gloves, splints, or casts. For most, however, the treatment regimen usually entails a minimum of 3 to 4 months. Although the healing and rehabilitation process is often lengthy and may seem costly, particularly in terms of time lost from competition, seldom do athletes regret the investment once they return to their highly skillful activities unencumbered by wrist impairment. Never does the sports medicine physician regret compliance with the principles of optimal care. PMID:9700415

Rettig, M E; Dassa, G L; Raskin, K B; Melone, C P

1998-07-01

343

The effects of screw removal on bone strain in an idealized plated bone model.  

PubMed

An idealized plated bone model was used to test the hypothesis that selected screw removal could alter the bone strain field and be a viable treatment for stress protection osteoporosis. Eighteen bone screw modifications were evaluated for their effects on bone strain. The three variables studied were number, position, and length of screws. Removal of two or four bone screws from an eight hole plate significantly increased the strain per load on the bone model over the values with eight screws in the plate (p less than 0.05). The four screw configurations increased bone strain more than the six screw configurations. It also was shown that the position of screws in the plate could significantly alter the bone strain per load results. Removal of six bone screws from an eight hole plate also increased the bone strain per load, but to excess in some tests. In those configurations, the results were not statistically different from the unplated configuration. Replacement of the full length screws with eight half length screws that engaged only the near cortex significantly reduced bone strain per load as compared with eight bicortical bone screws. PMID:3238883

Korvick, D L; Monville, J D; Pijanowski, G J; Phillips, J W

1988-01-01

344

Evaluation of calcium sulfate paste for augmentation of lumbar pedicle screw pullout strength  

Microsoft Academic Search

Background context: Many authors have evaluated the components responsible for ultimate pullout strength of pedicle screws. In these studies, one important variable has been the screw fixation. Because pedicle screw fixation has increased in popularity over recent years, so has the need for augmentation in difficult situations. Polymethylmethacrylate (PMMA) has been established as the gold standard in terms of strength

Michael T Rohmiller; Dugan Schwalm; R. Chris Glattes; Tarek G Elalayli; Dan M Spengler

2002-01-01

345

Pushout strength of tibial locking screws: Development of finite element models  

Microsoft Academic Search

This study investigated the bone holding power of tibial locking screws by mechanical testing and finite element analysis. In mechanical tests, five types of commercially available tibial locking screws: Howmedica, Osteo AG, Richards type I, Richards type II, and Synthes were inserted in a cylinder of polyurethane foam bone. Axial load was applied to the screw tip to push the

Jinn Lin

2003-01-01

346

Image-Guided Computer-Assisted Spine Surgery: A Pilot Study on Pedicle Screw Fixation  

Microsoft Academic Search

As the pedicle offers a strong point of attachment to the spine, several instrumentation systems using screws that go through the pedicle into the vertebral body have been developed to provide internal stability. All pedicle screw systems share the risk of damage to adjacent neural structures as a result of improper screw placement. A computer-assisted system allowing precise preoperative planning

Lutz Nolte; Lucia Zamorano; E. Arm; H. Visarius; Zaowei Jiang; U. Berlerman; O. Schwarzenbach

1996-01-01

347

Development and Testing of a Screw Compressor Supermarket Refrigeration System: Phase II, Final Report  

Microsoft Academic Search

A laboratory prototype screw compressor refrigeration system was designed, fabricated and tested under various evaporator and ambient conditions. The design is based on a Dunham-Bush vertical hermetic screw compressor and other standard refrigeration components. Results indicate that a screw compressor rack with vapor injection can increase the thermodynamic efficiency of low temperature refrigeration in supermarkets by 20 to 28% compared

H. Hamed Borhanian; William M. Toscano; Kang P. Lee

1987-01-01

348

Hamstring tendon fixation using interference screws: a biomechanical study in calf tibial bone  

Microsoft Academic Search

It has recently been shown that graft fixation close to the ACL insertion site is optimal in order to increase anterior knee stability. Hamstring tendon fixation using interference screws offers this possibility and a round threaded titanium interference screw has been previously developed. The use of a round threaded biodegradable interference screw may be equivalent. In addition, to increase initial

A Weiler; RF Hoffmann; AC Stähelin; HJ Bail; CJ Siepe; NP Südkamp

1998-01-01

349

Thermally-active screw dislocations in si nanowires and nanotubes.  

PubMed

Dislocations significantly influence the physical properties of nanomaterials. Nonequilibrium molecular dynamics simulations uncover significant reductions in thermal conductivity when <110> Si nanowires contain axial screw dislocations. The effect can act in combination with other known thermal conductivity limiting mechanisms, and thus can enable the further optimization of the figure of merit for a new family of complex thermoelectric nanomaterials. PMID:24574194

Xiong, Shiyun; Ma, Jihong; Volz, Sebastian; Dumitric, Traian

2014-05-01

350

Primary thoracoplasty and pedicle screw instrumentation in thoracic idiopathic scoliosis  

Microsoft Academic Search

Thoracoplasty in combination with spine fusion is an established method to address the rib cage deformity in idiopathic scoliosis. Most reports about thoracoplasty and scoliosis correction focused on Harrington or CD instrumentation. We report a retrospective analysis of 21 consecutive patients, who were treated with pedicle screw instrumentation for idiopathic thoracic scoliosis and concomitant thoracoplasty. Minimal follow up was 24

Kan Min; Beat Waelchli; Frederik Hahn

2005-01-01

351

Clinical Outcome of Modified Cervical Lateral Mass Screw Fixation Technique  

PubMed Central

Objective The purpose of this study was 1) to analyze clinically-executed cervical lateral mass screw fixation by the Kim's technique as suggested in the previous morphometric and cadaveric study and 2) to examine various complications and bicortical purchase that are important for b-one fusion. Methods A retrospective study was done on the charts, operative records, radiographs, and clinical follow up of thirty-nine patients. One hundred and seventy-eight lateral mass screws were analyzed. The spinal nerve injury, violation of the facet joint, vertebral artery injury, and the bicortical purchases were examined at each lateral mass. Results All thirty-nine patients received instrumentations with poly axial screws and rod systems, in which one hundred and seventy-eight screws in total. No vertebral artery injury or nerve root injury were observed. Sixteen facet joint violations were observed (9.0%). Bicortical purchases were achieved on one hundred and fifty-six (87.6%). Bone fusion was achieved in all patients. Conclusion The advantages of the Kim's technique are that it is performed by using given anatomical structures and that the complication rate is as low as those of other known techniques. The Kim's technique can be performed easily and safely without fluoroscopic assistance for the treatment of many cervical diseases.

Kim, Seong-Hwan; Seo, Won-Deog; Kim, Ki-Hong; Yeo, Hyung-Tae; Choi, Gi-Hwan

2012-01-01

352

Bone registration method for robot assisted surgery: pedicle screw insertion  

Microsoft Academic Search

SUMMARY A registration method that identifies bone geometry with respect to a robotic manipulator arm is presented. Although the method is generally applicable to many orthopaedic internal fixation, it was only demonstrated for the insertion of pedicle screws in vertebral bodies for spine fixation. The method relies upon obtaining an impression of the vertebral bodies. Computed Tomography scans of both

K Abdel-Malek; D P McGowan; V K Goel; D Kowalski; A Hager

1997-01-01

353

Theory of electrical resistance of multivalley semiconductors with screw dislocations  

Microsoft Academic Search

The diffusion theory of electrical resistance in multivalley semiconductors of Si-type with screw dislocations is developed. Intervalley electron transitions are taken into account. The effect of the inhomogeneous dislocation distribution on the electrical resistance of the crystal is considered.

Yu. V. Kornyushin; P. Streda

1973-01-01

354

INTERIOR VIEW OF JAMES HARRIS CUTTING SCREW THREADS INTO THE ...  

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

INTERIOR VIEW OF JAMES HARRIS CUTTING SCREW THREADS INTO THE INTERIOR OF FITTINGS ON ONE IN A BANK OF TAPPING MACHINES, EACH OPERATED BY THE SAME WORKER SIMULTANEOUSLY BUT TIMED TO REQUIRE WORKER ACTION AT INTERVALS THAT DO NOT INTERFERE WITH THE OTHER MACHINES. - Stockham Pipe & Fittings Company, Tapping Room, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

355

Twin-screw extrusion of ‘Pesta’-encapsulated biocontrol agents  

Microsoft Academic Search

‘Pesta’ granules in which fungal propagules are encapsulated in a wheat gluten matrix were prepared in multipound quantities by twin-screw extrusion and fluid bed drying. Dough formulations for extrusion contained wheat flour and kaolin, or wheat flour, kaolin and rice flour, plus water and fungal inoculum. Conidial inoculum of Colletotrichum truncatum, a pathogen of the weed hemp sesbania (Sesbania exaltata),

D. J. Daigle; W. J. Connick; C. D. Boyette; M. P. Lovisa; K. S. Williams; M. Watson

1997-01-01

356

An online measuring system for large screw threads  

NASA Astrophysics Data System (ADS)

An online measuring system can automatically detect large screw threads by using the neotype gauge head of threads, which includes a TESA inductance type transducer and a probe pin chosen according to the tooth-type of the screw thread. The contact measurement method was adopted on the basis of the synthetic measurement principle. The functional diameter of thread has experimentally been investigated and analyzed. The method of data processing is not only based on the principle of a precision measurement, but also on the principle of a dynamic test. The dynamic error is analyzed in this paper by spectrum analysis. The dynamic error is taken out and data of the functional diameter of the thread will be obtained. The analysis and the results of an actual measurement mentioned above show that the neotype gauge head of thread is capable to get the error and relative changes of the functional diameter of the screw thread. So the compatibility of saw-tooth thread can be evaluated. The system is not only suited for the test of saw-tooth thread, but also for that of other large threads with different tooth forms by using different types of probes. External threads as well as internal threads can be tested. Because the measurement strength of the neotype gauge head is much smaller than that of regular screw gauges, thus diminishing the measurement error resulting from the contact stress, the measurement precision of the gauging head can reach 1?m.

Zhang, Hongyan; Zhang, Guoxiong

2008-12-01

357

Conducting-polymer-driven actively shaped propellers and screws  

Microsoft Academic Search

Conducting polymer actuators are employed to create actively shaped hydrodynamic foils. The active foils are designed to allow control over camber, much like the ailerons of an airplane wing. Control of camber promises to enable variable thrust in propellers and screws, increased maneuverability, and improved stealth. The design and fabrication of the active foils are presented, the forces are measured

John D. Madden; Bryan Schmid; Serge R. Lafontaine; Peter G. A. Madden; Franz S. Hover; Karl McLetchie; Ian W. Hunter

2003-01-01

358

The formation mechanisms of interlocked microstructures in low-carbon high-strength steel weld metals  

SciTech Connect

Microstructural features and the formation mechanisms of interlocked microstructures of acicular ferrite in a low-carbon high-strength steel weld metal were investigated by means of computer-aided three-dimensional reconstruction technique and electron backscattered diffraction analysis. Multiple nucleation on inclusions, sympathetic nucleation or repeated nucleation, hard impingement, mutual intersection, and fixed orientation relationships of acicular ferrite grains were observed. They were all responsible for the formation of interlocked microstructures in the weld metal. During the process of isothermal transformation, the pre-formed acicular ferrite laths or plates partitioned austenite grains into many small and separate regions, and the growth of later formed acicular ferrite grains was confined in these small regions. Thus, the crystallographic grain size became smaller with the increasing holding time. Highlights: Black-Right-Pointing-Pointer Acicular ferrite is formed by multiple nucleation and sympathetic nucleation. Black-Right-Pointing-Pointer Hard impingement and intersection of ferrite grains occur at later stages. Black-Right-Pointing-Pointer The pre-formed ferrite laths partition austenite grains into smaller regions. Black-Right-Pointing-Pointer The growth of later formed ferrite grains is confined in the smaller regions.

Wan, X.L.; Wang, H.H.; Cheng, L.; Wu, K.M., E-mail: wukaiming2000@yahoo.com

2012-05-15

359

Interlocked optimization and fast gradient algorithm for a seismic inverse problem  

SciTech Connect

Highlights: {yields} A 2D extension of the 1D nonlinear inversion of well-seismic data is given. {yields} Appropriate regularization yields a well-determined large scale inverse problem. {yields} An interlocked optimization loop acts as an efficient preconditioner. {yields} The adjoint state method is used to compute the misfit function gradient. {yields} Domain decomposition method yields an efficient parallel implementation. - Abstract: We give a nonlinear inverse method for seismic data recorded in a well from sources at several offsets from the borehole in a 2D acoustic framework. Given the velocity field, approximate values of the impedance are recovered. This is a 2D extension of the 1D inversion of vertical seismic profiles . The inverse problem generates a large scale undetermined ill-conditioned problem. Appropriate regularization terms render the problem well-determined. An interlocked optimization algorithm yields an efficient preconditioning. A gradient algorithm based on the adjoint state method and domain decomposition gives a fast parallel numerical method. For a realistic test case, convergence is attained in an acceptable time with 128 processors.

Metivier, Ludovic, E-mail: ludovic.metivier@gmail.com [LAGA, Universite Paris XIII, 99 Avenue Jean-Baptiste Clement, 93000 Epinay-Villetaneuse (France)

2011-08-10

360

Maxillary expansion with the memory screw: a preliminary investigation  

PubMed Central

Objective The purpose of this study was to investigate the effects of a newly developed rapid maxillary expansion screw-the memory screw-over 6 months. Methods Five subjects, aged between 11.7 and 13.75 years, were enrolled in this study. All subjects underwent placement of a maxillary expansion appliance containing superelastic nickel-titanium open-coil springs in its screw bed. The parents of the patients and/or the patients themselves were instructed to activate the expansion screw by 2 quarter-turns 3 times a day (morning, midday, and evening; 6 quarter-turns a day). The mean expansion period was 7.52 ± 1.04 days. Dentoskeletal effects of the procedure, including dentoalveolar inclination, were evaluated. Measurements of all the parameters were repeated after 6 months of retention in order to check for relapse. Results Sella-Nasion-A point (SNA) and Sella-Nasion/Gonion-Menton angles increased, and Sella-Nasion-B point (SNB) angle decreased in all the subjects during the expansion phase. However, they approximated to the initial values at the end of 6 months. On the other hand, the increments in maxillary apical base (Mxr-Mxl) and intermolar widths was quite stable. As expected, some amount of dentoalveolar tipping was observed. Conclusions The newly developed memory expansion screw offers advantages of both rapid and slow expansion procedures. It widens the midpalatal suture and expands the maxilla with relatively lighter forces and within a short time. In addition, the resultant increments in the maxillary apical base and intermolar width remained quite stable even after 6 months of retention.

Halicioglu, Koray; Kiki, Ali

2012-01-01

361

The general theory of blade screws including propellers, fans, helicopter screws, helicoidal pumps, turbo-motors, and different kinds of helicoidal blades  

NASA Technical Reports Server (NTRS)

Report presents a theory which gives a complete picture and an exact quantitative analysis of the whole phenomenon of the working of blade screws, but also unites in a continuous whole the entire scale of states of work conceivable for a blade screw. Chapter 1 is devoted to the establishment of the system of fundamental equations relating to the blade screw. Chapter 2 contains the general discussion of the 16 states of work which may establish themselves for a blade screw. The existence of the vortex ring state and the whirling phenomenon are established. All the fundamental functions which enter the blade-screw theory are submitted to a general analytical discussion. The general outline of the curve of the specific function is examined. Two limited cases of the work of the screw, the screw with a zero constructive pitch and the screw with an infinite constructive pitch, are pointed out. Chapter 3 is devoted to the study of the propulsive screw or propeller. (author)

De Bothezat, George

1920-01-01

362

Distal Ulna Hook Plate: Angular Stable Implant for Fixation of Distal Ulna  

PubMed Central

Distal ulna fractures, especially styloid injuries, classically have not been repaired, and only recently have these injuries been considered important. Certain fracture patterns of the distal ulna contribute to distal radioulnar joint (DRUJ) incongruity and potential instability. Appropriate fixation of the distal ulna is frequently difficult for several reasons: (1) high incidence of osteoporois in the affected patient population, (2) proximity of the injury to articular surfaces, and (3) lack of a proper implant to treat these injuries. The 2.0-mm locking compression distal ulna plate (LC-DUP) is an anatomically contoured implant with a low profile and fixed angle that provides proper stability to treat injuries of the distal ulna. The plate was designed for the treatment of distal ulna fractures, but its success has led to an extension of its indications to be used in treating symptomatic basistyloid ulnar nonunions and in ulnar shortening osteotomy for ulnocarpal abutment syndrome. The authors' description of the techniques used for each indication as well as their perspectives in the treatment of distal ulna injuries are described in detail in this report.

Nunez, Fiesky A.; Li, Zhongyu; Campbell, Douglas; Nunez, Fiesky A.

2013-01-01

363

A new approach in maxillary molar distalization: Intraoral bodily molar distalizer  

Microsoft Academic Search

The objectives of our study were to achieve bodily molar distalization, avoid distal tipping of molars, eliminate the need for patient cooperation (no headgear, no elastics, and no esthetic and social concern), and finally to minimize the treatment period and maximize the treatment efficiency. The study was carried out on 5 males and 10 females, a total of 15 patients.

Ahmet Keles; Korkmaz Sayinsu

2000-01-01

364

Complications After Open Distal Clavicle Excision  

PubMed Central

Isolated distal clavicle excision performed as an open procedure has been considered safe and, in the literature, has been considered the standard for comparison with arthroscopic distal clavicle excisions. However, we noticed isolated open distal clavicle excision was associated with a number of complications. We therefore raised two questions about the complication rate in a cohort of our patients who had undergone this procedure: (1) What was the complication rate and how did it compare to that in the existing literature on this subject? and (2) Were the complications in our cohort similar to those previously reported? We studied 42 patients who underwent an isolated distal clavicle excision between 1992 and 2003. There were 27 complications (64%), which was substantially higher than rates previously reported. Complications in our cohort not previously reported included continued acromioclavicular joint tenderness and scar hypertrophy. Our study suggests complications after open distal clavicle excisions may be more frequent than and may differ from previously reported rates and types. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Chronopoulos, Efstathis; Gill, Harpreet S.; Freehill, Michael T.; Petersen, Steve A.

2008-01-01

365

Percutaneous pedicle screw placement in the thoracic spine: A cadaveric study  

PubMed Central

Study Design: A cadaveric study to determine the accuracy of percutaneous screw placement in the thoracic spine using standard fluoroscopic guidance. Summary of Background Data: While use of percutaneous pedicle screws in the lumbar spine has increased rapidly, its acceptance in the thoracic spine has been slower. As indications for pedicle screw fixation increase in the thoracic spine so will the need to perform accurate and safe placement of percutaneous screws with or without image navigation. To date, no study has determined the accuracy of percutaneous thoracic pedicle screw placement without use of stereotactic imaging guidance. Materials and Methods: Eighty-six thoracic pedicle screw placements were performed in four cadaveric thoracic spines from T1 to T12. At each level, Ferguson anterior–posterior fluoroscopy was used to localize the pedicle and define the entry point. Screw placement was attempted unless the borders of the pedicle could not be delineated solely using intraoperative fluoroscopic guidance. The cadavers were assessed using pre- and postprocedural computed tomography (CT) scans as well as dissected and visually inspected in order to determine the medial breach rate. Results: Ninety pedicles were attempted and 86 screws were placed. CT analysis of screw placement accuracy revealed that only one screw (1.2%) breached the medial aspect of the pedicle by more than 2 mm. A total of four screws (4.7%) were found to have breached medially by visual inspection (three Grade 1 and one Grade 2). One (1.2%) lateral breach was greater than 2 mm and no screw violated the neural foramen. The correlation coefficient of pedicle screw violations and pedicle diameter was found to be 0.96. Conclusions: This cadaveric study shows that percutaneous pedicle screw placement can be performed in the thoracic spine without a significant increase in the pedicle breach rate as compared with standard open techniques. A small percentage (4.4%) of pedicles, especially high in the thoracic spine, may not be safely visualized.

Hardin, Carolyn A.; Nimjee, Shahid M.; Karikari, Isaac O.; Agrawal, Abhishek; Fessler, Richard G.; Isaacs, Robert E.

2013-01-01

366

A BIOMECHANICAL EVALUATION OF THE GAMMA NAIL  

Microsoft Academic Search

We examined the effect of the Gamma nail on strain distribution in the proximal femur, using ten cadaver femora instrumented with six unidirectional strain gauges along the medial and lateral cortices. The femora were loaded to 1800 N and strains were determined with or without distal interlocking screws before and after experimentally created two-part and four-part fractures. Motion of the

SHEPHERD F. ROSENBLUM; JOSEPH D. ZUCKERMAN; FREDERICK J. KUMMER; BENJAMIN S. TAM

367

Osteochondritis of the Distal Tibial Epiphysis  

PubMed Central

Osteochondritis of the distal tibial epiphysis is a very rare entity. 9 cases have been described in 7 articles and 8 other cases have been mentioned in textbooks. This paper describes the 10th case of osteochondritis of the distal tibial epiphysis and summarizes the clinical and radiological presentations of the 9 other cases. The etiology of this entity is well debated in the literature. We believe that it results from a vascular abnormality in the distal tibial epiphysis associated with a mechanical stress (trauma, excessive overload, etc.). Since it is a self-limited disease, the prognosis is good and the younger the patient is the better the prognosis will be. In general, this entity responds well to conservative treatment.

EL Hajj, Firass; Sebaaly, Amer; Kharrat, Khalil; Ghanem, Ismat

2012-01-01

368

Distal Cervical Internal Carotid Artery Stenosis  

PubMed Central

This report describes a case of distal cervical internal carotid artery (ICA) occlusive lesion managed by saphenous interposition vein graft after exposure of the ICA up to the skull base. The skull base approach described herein emphasizes the mobilization of the mandible without mandibular osteotomy or disarticulation. Instead, the stylomandibular and stylosphenoidal ligaments are resected to allow mandibular mobilization. In addition, the distal ICA lesion represented a form of diffuse intimal thickening without any plaque formation. This required the resection of the thickened, stenotic segment and reconstruction of the distal cervical ICA with a saphenous interposition graft. The surgical management implications of diffuse intimal thickening are discussed. ImagesFigure 1Figure 4Figure 5Figure 6p114-b

Awasthi, Deepak; Smith, Roger

1994-01-01

369

Topological and Conformational Effects on Electron Transfer Dynamics in Porphyrin-[60]Fullerene Interlocked Systems.  

PubMed

The effect of molecular topology, and conformation on the dynamics of photoinduced electron transfer (ET) processes has been studied in interlocked electron donor-acceptor systems, specifically rotaxanes with zinc(II)-tetraphenylporphyrin (ZnP) electron donor and [60]fullerene (C(60)) as the electron acceptor. Formation or cleavage of coordinative bonds was used to induce major topological and conformational changes in the interlocked architecture. In the first approach, the tweezers-like structure created by the two ZnP stopper groups on the thread was used as a recognition site for complexation of 1,4-diazabicyclo[2.2.2]octane (DABCO), which creates a bridge between the two ZnP moieties on the rotaxane, generating a catenane structure. The photoinduced processes in the DABCO-complexed (ZnP)(2)-[2]catenate-C(60) system were compared with those of the (ZnP)(2)-rotaxane-C(60) precursor and the previously reported ZnP-[2]catenate-C(60). Steady-state emission and transient absorption studies showed that a similar multistep ET pathway emerged for rotaxanes and catenanes upon photoexcitation at various wavelengths, ultimately resulting in a long-lived ZnP(•+)/C(60) (•-) charge separated radical pair state. However, the decay kinetics of the latter states clearly reflect the topological differences between the rotaxane, the catenate, and DABCO-complexed-catenate architectures. The lifetime of the long-distance ZnP(•+)-[Cu(I)phen(2)](+)-C(60) (•-) charge separated state is more than four times longer in 3 (1.03 µs) than in 1 (0.24 µs) and approaches that in catenate 2 (1.1 µs). The results clearly showed that adoption of a catenane from a rotaxane topology inhibits the charge recombination process. In a second approach, the Cu(I) ion used as template to assemble the (ZnP)(2)-[Cu(I)phen(2)](+)-C(60) rotaxane was removed, and structural analysis suggested a major topographical change occurred, such that charge separation between the chromophores was no longer observed upon photoexcitation in nonpolar as well as polar solvents. Only ZnP and C(60) triplet excited states were observed upon laser excitation. These results highlighted the critical importance of the central Cu(I) ion for long range ET processes in these large interlocked electron donor-acceptor systems. PMID:22984324

Megiatto, Jackson D; Schuster, David I; de Miguel, Gustavo; Wolfrum, Silke; Guldi, Dirk M

2012-07-10

370

Recent advances in distal tubular potassium handling  

PubMed Central

It is well known that sodium reabsorption and aldosterone play important roles in potassium secretion by the aldosterone-sensitive distal nephron. Sodium- and aldosterone-independent mechanisms also exist. This review focuses on some recent studies that provide novel insights into the sodium- and aldosterone-independent potassium secretion by the aldosterone-sensitive distal nephron. In addition, we discuss a study reporting on the regulation of the mammalian potassium kidney channel ROMK by intracellular and extracellular magnesium, which may be important in the pathogenesis of persistent hypokalemia in patients with concomitant potassium and magnesium deficiency. We also discuss outstanding questions and propose working models for future investigation.

Rodan, Aylin R.; Cheng, Chih-Jen

2011-01-01

371

Torsion of wandering spleen and distal pancreas  

SciTech Connect

Wandering spleen is the term applied to the condition in which a long pedicle allows the spleen to lie in an abnormal location. Torsion of a wandering spleen is an unusual cause of an acute abdomen and is rarely diagnosed preoperatively. Associated torsion of the distal pancreas is even more uncommon. The authors describe a patient with torsion of a wandering spleen and distal pancreas, who was correctly diagnosed, and define the merits of the imaging methods used. The initial examination should be /sup 99//sup m/Tc-sulfur colloid liner-spleen scanning.

Sheflin, J.R.; Lee, C.M.; Kretchmar, K.A.

1984-01-01

372

Distal-Selective Hydroformylation using Scaffolding Catalysis.  

PubMed

In hydroformylation, phosphorus-based directing groups have been consistently successful at placing the aldehyde on the carbon proximal to the directing group. The design and synthesis of a novel catalytic directing group are reported that promotes aldehyde formation on the carbon distal relative to the directing functionality. This scaffolding ligand, which operates through a reversible covalent bond to the substrate, has been applied to the diastereoselective hydroformylation of homoallylic alcohols to afford ?-lactones selectively. Altering the distance between the alcohol and the olefin revealed that homoallylic alcohols gives the distal lactone with the highest levels of regioselectivity. PMID:24902624

Joe, Candice L; Blaisdell, Thomas P; Geoghan, Allison F; Tan, Kian L

2014-06-18

373

Definition and means of maintaining the process vacuum liquid detection interlock systems portion of the PFP safety envelope  

SciTech Connect

The HC-4, HC-7, HC-227s and the tank 50 High Level Liquid detection interlock systems detect the potential for a liquid up take into the 26 inch Vacuum Headers. All of the detectors are well upstream of the 26 inch Vacuum Liquid Detection system that is designed to prevent a criticality due to liquid uptake. Failure of any of the four glovebox liquid detection systems would not impact the operation of the 26 inch Vacuum Liquid Detection system. The systems are completely separate. The liquid detectors and interlocks were installed after an incident in HC-227s resulted in a significant volume of RMC feed grade plutonium solution to be drawn out of the glovebox and into the vacuum header. The vacuum trap liquid detection interlock system operability is verified by a weekly functional test per maintenance procedure 2222124. Removal of the HC-7 Liquid Detection Interlock system from the WHC-SD-CP-SDD-013 document will not impact this maintenance procedure.

THOMAS, R.J.

1999-09-01

374

Stress fracture of the proximal femur after screw removal.  

PubMed

We describe a case of stress fracture of the proximal femur occurring in a patient after removal of an internal fixation device for a comminuted subtrochanteric fracture. The presenting clinical picture resembled a late postoperative infection with a positive technetium and gallium bone scan and normal radiological findings. The stress fracture occurred after removal of the fixation device when the patient started full weight-bearing. The patient was treated initially as having osteomyelitis until a second X-radiograph some weeks later demonstrated a stress fracture through one of the previous screw holes. This case illustrates well the possible complication of a insufficiency fracture subsequent to the occurrence of stress risers through screw holes in a weakened bone when submitted to normal load. The clinical presentation may sometimes resemble late postoperative infection. PMID:8775714

Velkes, S; Nerubay, J; Lokiec, F

1996-01-01

375

Medial migration of lag screw after gamma nailing.  

PubMed

Fractures of the proximal femur are common in the elderly population. Intramedullary nailing has become the standard treatment for intertrochanteric fractures although several extramedullary implants (e.g. dynamic hip screw (DHS), blade plate, locking compression plate (LCP), etc.) exist. However, despite this being a very common operation in traumatology, there are numerous associated complications. We report the rare complication of the migration of the medial lag screw into the pelvis at five and a half weeks postoperatively. The implant was removed and replaced by a total hip arthroplasty with simultaneous grafting of the acetabular defect and strapping of the greater trochanter. The evolution was favourable. We also present a review of the literature and analyze our case. PMID:24933440

Thein, Eric; De Cannière, Alexandre; Burn, Alexandre; Borens, Olivier

2014-08-01

376

Screw pumps provide high efficiency in transport of Orinoco bitumen  

SciTech Connect

One of the world`s largest known deposits of extra natural bitumen is located in the Orinoco River basin of eastern Venezuela. Production and transportation of an emulsion of bitumen and water is one of the major projects being directed by Petroleos de Venezuela S.A. This paper reviews the pump selection options considered in transporting this bitumen to a viable processing facility. The three pump types evaluated were centrifugal, reciprocating, or rotary screw. Performance and cost parameters are evaluated and the screw pump was determined to be the most economical, high performance choice. The paper goes on to describe the installation of the main transport lines and efficiency of these new pumps.

Brennan, J.R. [IMO Industries, Inc., Monroe, NC (United States)

1995-03-01

377

Analysis of Eyring-Powell fluid in helical screw rheometer.  

PubMed

This paper aims to study the flow of an incompressible, isothermal Eyring-Powell fluid in a helical screw rheometer. The complicated geometry of the helical screw rheometer is simplified by "unwrapping or flattening" the channel, lands, and the outside rotating barrel, assuming the width of the channel is larger as compared to the depth. The developed second order nonlinear differential equations are solved by using Adomian decomposition method. Analytical expressions are obtained for the velocity profiles, shear stresses, shear at wall, force exerted on fluid, volume flow rates, and average velocity. The effect of non-Newtonian parameters, pressure gradients, and flight angle on the velocity profiles is noticed with the help of graphical representation. The observation confirmed the vital role of involved parameters during the extrusion process. PMID:24707194

Siddiqui, A M; Haroon, T; Zeb, M

2014-01-01

378

Delayed perforation of the aorta by a thoracic pedicle screw  

PubMed Central

Pedicle screw instrumentation has become increasingly popular during the past 20 years and a vast selection of products is available on the market. With rising implantation rates, reports about specific complications also have increased. The main reason for these complications is the fact that the course of the pedicle and in turn the positioning of the pedicle screw cannot be adequately controlled visually. Based on the anatomy of the surrounding structures, complications caused by malpositioning can be divided into three main groups: mechanical, neurological and vascular. Beyond mechanical limitations of spinal motion, nerve injury can lead to neurological problems while injuries to vascular structures usually cause hemorrhage. These typical problems in general become apparent intraoperatively or in the immediate postoperative course. We report on a rare delayed complication and analyze the factors that led to it. In addition, we outline our treatment strategy. The goal has to be to avoid such problems in the future by using suitable navigational aids.

Birkenmaier, Christof; Fottner, Andreas; Jansson, Volkmar; Durr, Hans Roland

2008-01-01

379

D0 Central Tracking Solenoid Energizatino, Controls, Interlocks and Quench Protection Initial Validation Procedures  

SciTech Connect

This note presents the inspection and tests to be performed on the DZERO solenoid energization, controls, interlocks and quench protection system before it is energized for the first time. This test is to be performed with a 5000A jumper at the end of the bus instead of the solenoid. This system is based in DZERO room 511. A copy of this note shall be annotated, signed and dated by the person coordinating the procedure; and filed with the system maintenance records. Annotations shall include comments about any aspect of the procedure that is abnormal or unsuccessful. The following inspections and tests shall be performed by persons knowledgeable about the system. Each individual test step should be reviewed and understood before proceeding with that step.

Jaskierny, W.; Hance, R.; /Fermilab

1998-01-27

380

A Molecular-Based Magnet with a Fully Interlocked Three-Dimensional Structure  

NASA Astrophysics Data System (ADS)

A compound has been synthesized with the formula (rad)_2Mn_2[Cu(opba)]_3(DMSO)_2.2H_2O, where rad^+ is 2-(4-N-methylpyridinium)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, opba is orthophenylenebis (oxamato), and DMSO is dimethyl sulfoxide. It consists of two nearly perpendicular graphite-like networks with edge-sharing Mn(II)_6Cu(II)_6 hexagons. The two networks are fully interlocked with the same topological relationship as that between adjacent rings of a necklace. The compound has three kinds of spin carriers: Mn(II) and Cu(II) ions, antiferromagnetically coupled through oxamato bridges, and rad^+ radical cations, bridging the Cu(II) ions through the nitronyl nitroxide groups and forming Cu-rad chains. The temperature dependence of the magnetization reveals that below 22.5 K, the compound behaves as a magnet.

Stumpf, Humberto O.; Ouahab, Lahcene; Pei, Yu; Grandjean, Daniel; Kahn, Olivier

1993-07-01

381

Testing the permeability and corrosion resistance of micro-mechanically interlocked joints  

NASA Astrophysics Data System (ADS)

Micro-mechanical interlocking (MMI) can be applied to create new and interesting composite materials. We have employed laser structuring to achieve MMI between stainless steel and plastic with extremely high joint strength. However, the water permeability and corrosion resistance of the joint must be examined. For many industrially relevant applications it is important to keep water away from certain parts and to prevent the sample from corroding. A thorough study of the permeability of the interconnected samples at different temperatures and after employing different laser-structuring techniques is conducted. The permeability seems to be consistent with the Hagen-Poiseuille equation independent of the laser structuring technique and is orders of magnitudes larger than the diffusion rate through the plastic. Two different types of corrosion tests have been undertaken, and we show that care must be taken in order not to degrade the corrosion resistance of the sample to an unacceptable level.

Byskov-Nielsen, Jeppe; Holm, Allan H.; Højsholt, Rune; Sá, Pedro; Balling, Peter

2011-09-01

382

Interlocked grain growth of YBCO film on magnesium oxide as observed by scanning tunneling microscopy  

SciTech Connect

Thin films of YBa[sub 2]Cu[sub 3]O[sub 7] on MgO deposited by RF magnetron sputtering to study their superconducting behavior, were examined by a Scanning Tunneling Microscope. The films were deposited at room temperature, sintered exsitu at 850 C, 900 C, 930 C, 950 C and 980 C for 30 minutes each and cooled at rate of 100 C per hour in oxygen ambient. Topographic images taken in air show that the films which were initially amorphous in nature, gradually transform to a layered grain structure with the increase of sintering temperature. Films sintered at temperatures above 900 C are c-axis oriented and have a coarse grain structure. These grains layers of neighboring grains. The mechanism of interlocking of layers from adjacent grains and its possible influence on the superconducting properties has been discussed.

Rao, M.V.H.; Mishra, S.K.; Pathak, L.C.; Mathur, B.K.; Bhattacharya, D.; Chopra, K.L. (Indian Inst. of Technology, Kharagpur (India))

1993-03-01

383

Charged residues dominate a unique interlocking topography in the heterodimeric cytokine interleukin-12  

PubMed Central

Human interleukin-12 (IL-12, p70) is an early pro-inflammatory cytokine, comprising two disulfide-linked subunits, p35 and p40. We solved the crystal structures of monomeric human p40 at 2.5 ? and the human p70 complex at 2.8 ? resolution, which reveals that IL-12 is similar to class 1 cytokine–receptor complexes. They also include the first description of an N-terminal immunoglobulin-like domain, found on the p40 subunit. Several charged residues from p35 and p40 intercalate to form a unique interlocking topography, shown by mutagenesis to be critical for p70 formation. A central arginine residue from p35 projects into a deep pocket on p40, which may be an ideal target for a small molecule antagonist of IL-12 formation.

Yoon, Christina; Johnston, Steven C.; Tang, Jin; Stahl, Mark; Tobin, James F.; Somers, William S.

2000-01-01

384

Radiation interlocks: The choice between conventional hard-wired logic and computer-based systems  

SciTech Connect

During the past few years, the use of computers in radiation safety systems has become more widespread. This is not surprising given the ubiquitous nature of computers in the modern technological world. But is a computer a good choice for the central logic element of a personnel safety system. Recent accidents at computer controlled medical accelerators would indicate that extreme care must be exercised if malfunctions are to be avoided. The Department of Energy has recently established a sub-committee to formulate recommendations on the use of computers in safety systems for accelerators. This paper will review the status of the committee's recommendations, and describe radiation protection interlock systems as applied to both accelerators and to irradiation facilities. Comparisons are made between the conventional relay approach and designs using computers. 6 refs., 6 figs.

Crook, K.F.

1986-11-01

385

Disturbed basal ice seen in radio echo images coincide with zones of big interlocking ice crystals.  

NASA Astrophysics Data System (ADS)

Improvement of the depth sounding radio echo sounding (RES) over Antarctica and Greenland Ice Sheet has made it possible to map the near basal layers that have not been 'seen' earlier due to the very high demand of attenuation needed to reach through more than 3000m of ice. The RES internal reflectors show that the near basal ice at many locations has disturbed layering. At the locations where ice cores reach the bedrock both in Greenland and Antarctica studies of the ice crystal size and orientation show that the near basal ice has big and interlocking ice crystals which suggests the ice is not actively deforming. These observations challenge the often used constitutive equations like Glens flow law in ice sheet modelling. A discussion of the impact of the RES findings on ice sheet modeling and the quest to find the oldest ice in Antarctic based on the anisotropy of the basal ice will follow.

Dahl-Jensen, Dorthe; Gogineni, Sivaprasad; Panton, Christian

2014-05-01

386

The Community Structure of the European Network of Interlocking Directorates 2005-2010  

PubMed Central

The boards of directors at large European companies overlap with each other to a sizable extent both within and across national borders. This could have important economic, political and management consequences. In this work we study in detail the topological structure of the networks that arise from this phenomenon. Using a comprehensive information database, we reconstruct the implicit networks of shared directorates among the top 300 European firms in 2005 and 2010, and suggest a number of novel ways to explore the trans-nationality of such business elite networks. Powerful community detection heuristics indicate that geography still plays an important role: there exist clear communities and they have a distinct national character. Nonetheless, from 2005 to 2010 we observe a densification of the boards interlocks network and a larger transnational orientation in its communities. Together with central actors and assortativity analyses, we provide statistical evidence that, at the level of corporate governance, Europe is getting closer.

Heemskerk, Eelke M.; Daolio, Fabio; Tomassini, Marco

2013-01-01

387

The community structure of the European network of interlocking directorates 2005-2010.  

PubMed

The boards of directors at large European companies overlap with each other to a sizable extent both within and across national borders. This could have important economic, political and management consequences. In this work we study in detail the topological structure of the networks that arise from this phenomenon. Using a comprehensive information database, we reconstruct the implicit networks of shared directorates among the top 300 European firms in 2005 and 2010, and suggest a number of novel ways to explore the trans-nationality of such business elite networks. Powerful community detection heuristics indicate that geography still plays an important role: there exist clear communities and they have a distinct national character. Nonetheless, from 2005 to 2010 we observe a densification of the boards interlocks network and a larger transnational orientation in its communities. Together with central actors and assortativity analyses, we provide statistical evidence that, at the level of corporate governance, Europe is getting closer. PMID:23894318

Heemskerk, Eelke M; Daolio, Fabio; Tomassini, Marco

2013-01-01

388

Accuracy and safety of free-hand pedicle screw fixation in age less than 10 years  

PubMed Central

Background: Pedicle screws are being used commonly in the treatment of various spinal disorders. However, use of pedicle screws in the pediatric population is not routinely recommended because of the risk of complications. The present study was to evaluate the safety of pedicle screws placed in children aged less than 10 years with spinal deformities and to determine the accuracy and complication (early and late) of pedicle screw placement using the postoperative computed tomography (CT) scans. Materials and Methods: Thirty one patients (11 males and 20 females) who underwent 261 pedicle screw fixations (177 in thoracic vertebrae and 84 in lumbar vertebrae) for a variety of pediatric spinal deformities at a single institution were included in the study. The average age of patients was 7 years and 10 months. These patients underwent postoperative CT scan which was assessed by two independent observers (spine surgeons) not involved in the treatment. Results: Breach rate was 5.4% (14/261 screws) for all pedicles. Of the 177 screws placed in the thoracic spine, 13 (7.3%) had breached the pedicle, that is 92.7% of the screws were accurately placed within pedicles. Seven screws (4%) had breached the medial pedicle wall, 4 screws (2.3%) had breached the lateral pedicle wall and 2 screws (1.1%) had breached the superior or inferior pedicle wall respectively. Of the 84 screws placed in the lumbar spine, 83 (98.8%) screws were accurately placed within the pedicle. Only 1 screw (1.2%) was found to be laterally displaced. In addition, the breach rate was found to be 4.2% (11/261 screws) with respect to the vertebral bodies. No neurological, vascular or visceral complications were encountered. Conclusions: The accuracy of pedicle screw placement in pedicles and vertebral bodies were 94.6% and 95.8% respectively and there was no complication related to screw placement noted until the last followup. These results suggest that free-hand pedicle screw fixation can be safely used in patients younger than 10 years to treat a variety of spinal disorders.

Seo, Hyoung Yeon; Yim, Ji Hyeon; Heo, Jung Pil; Patil, Abhishek S; Na, Seung Min; Kim, Sung Kyu; Chung, Jae Yoon

2013-01-01

389

Subaxial subluxation after atlantoaxial transarticular screw fixation in rheumatoid patients  

PubMed Central

The most common cervical abnormality associated with rheumatoid arthritis (RA) is atlantoaxial subluxation, and atlantoaxial transarticular screw fixation has proved to be one of the most reliable, stable fixation techniques for treating atlantoaxial subluxation. Following C1–C2 fixation, however, subaxial subluxation reportedly can bring about neurological deterioration and require secondary operative interventions. Rheumatoid patients appear to have a higher risk, but there has been no systematic comparison between rheumatoid and non-rheumatoid patients. Contributing radiological factors to the subluxation have also not been evaluated. The objective of this study was to evaluate subaxial subluxation after atlantoaxial transarticular screw fixation in patients with and without RA and to find contributing factors. Forty-three patients who submitted to atlantoaxial transarticular screw fixation without any concomitant operation were followed up for more than 1 year. Subaxial subluxation and related radiological factors were evaluated by functional X-ray measurements. Statistical analyses showed that aggravations of subluxation of 2.5 mm or greater were more likely to occur in RA patients than in non-RA patients over an average of 4.2 years of follow-up, and postoperative subluxation occurred in the anterior direction in the upper cervical spine. X-ray evaluations revealed that such patients had a significantly smaller postoperative C2–C7 angle, and that the postoperative AA angle correlated negatively with this. Furthermore, anterior subluxation aggravation was significantly correlated with the perioperative atlantoaxial and C2–C7 angle changes, and these two changes were strongly correlated to each other. In conclusion, after atlantoaxial transarticular screw fixation, rheumatoid patients have a greater risk of developing subaxial subluxations. The increase of the atlantoaxial angel at the operation can lead to a decrease in the C2–C7 angle, followed by anterior subluxation of the upper cervical spine and possibly neurological deterioration.

Neo, Masashi; Sakamoto, Takeshi; Fujibayashi, Shunsuke; Yoshitomi, Hiroyuki; Nakamura, Takashi

2009-01-01

390

Modified Austin bunionectomy with single screw fixation: a comparison study.  

PubMed

The authors present a new modification of the Austin bunionectomy with single 2.7-mm. cortical screw fixation, and a comparison study with the standard osteotomy fixation using a single Kirschner wire. The results include subjective postoperative evaluation as well as objective radiographic analysis. Suggestions are made that this type of procedure is indeed a viable alternative in a large patient population suffering from hallux abducto valgus deformities. PMID:2794359

Clancy, J T; Berlin, S J; Giordano, M L; Sherman, S A

1989-01-01

391

Management of odontoid fractures with percutaneous anterior odontoid screw fixation  

Microsoft Academic Search

Minimally invasive techniques have revolutionized the management of a variety of spinal disorders. The authors of this study\\u000a describe a new instrument and a percutaneous technique for anterior odontoid screw fixation, and evaluate its safety and efficacy\\u000a in the treatment of patients with odontoid fractures. Ten patients (6 males and 4 females) with odontoid fractures were treated\\u000a by percutaneous anterior

Yong-Long Chi; Xiang-Yang Wang; Hua-Zi Xu; Yan Lin; Qi-Shan Huang; Fang-Min Mao; Wen-Fei Ni; Sheng Wang; Li-Yang Dai

2007-01-01

392

Recent results of the toroidal screw pinch SPICA 2  

NASA Astrophysics Data System (ADS)

With discharges in the slow screw pinch mode (without shock wave heating), high beta plasmas were studied. In this mode the power crowbar banks are switched on when the predischarge current and the bias field reach their maximum value. At these low plasma currents (less than 70 kA) the stabilization by the conducting wall could not prevent disastrous plasma-wall contact. It is concluded that for this mode of operation a pulsed vertical field is essential.

Lassing, H. S.; Lok, J.; Vandermeer, A. F. G.; Navratil, G. A.; Oepts, D.; Oomens, A. A. M.; Verreck, M.

1988-06-01

393

Femoral nailing with transverse locking screws through the femoral neck  

Microsoft Academic Search

We treated 55 patients with subtrochanteric or comminuted femoral fractures with a transverse locking femoral nail (Alta, Howmedica). This nail was positioned more cephalad than usual so that at least one fixation screw was located in the femoral neck or head. Forty-seven fractures (20 subtrochanteric and 27 diaphyseal) were available for follow-up averaging 12 months (3-35). The time to radiographic

B. H. Ziran; A. D. Wasan; M. W. Chapman

2001-01-01

394

External jig-aided intramedullary interlocking nailing of diaphyseal fractures: experience from a tropical developing centre.  

PubMed

Intramedullary interlocking nailing for diaphyseal fractures is a standard treatment option in affluent societies. These procedures are often performed under image intensifier guidance. The cost of these gadgets precludes their common use in resource poor regions. External jig-aided intramedullary interlocking nailing is relatively cheap and offers the chance for performing these procedures in resource poor regions. The aim of this study was to document the advantages, challenges and outcome of this form of treatment in a resource poor setting. The Surgical Implant Generation Network (SIGN) implants and instrumentation were used for this study. Thirty-seven limbs in 35 patients were included. There were 30 males and five females giving a ratio of 6:1. The mean age was 35?±?11.9 years with a range of 15-61 years. The femur and tibia were the bones studied with a total of 23 and 14 fractures, respectively (ratio 1.6:1). There were 14 comminuted fractures, two segmented fractures, six mal-unions, eight non-unions and seven simple fractures. Road traffic accidents were the most common cause of injuries with motorcycle accidents accounting for 19 (57.4%) cases. The mean follow-up period was 22?±?5.32 months, mean time to union was 16.9?±?5.4 weeks and the major complication was osteomyelitis (10.8%). We conclude that this is a viable treatment option for musculoskeletal injuries in resource poor regions. Education to encourage early acceptance of surgical intervention and reduced patronage of traditional bone setting for injudicious interventions can reduce the infective complication rates. PMID:20148329

Ikpeme, Ikpeme; Ngim, Ngim; Udosen, Anthony; Onuba, Obiora; Enembe, Okokon; Bello, Segun

2011-01-01

395

[Biomechanics of femoral interlocking nails at the bone-implant transition].  

PubMed

Today there is a variety of different interlocking intramedullary nail designs available for the femur-each designed with a different approach to achieve stability for fracture fixation. We compared different nail types in the bone-implant complex (BIC) of four unreamed solid nails and a slotted, reamed nail to see if there are major differences in stiffness for axial load, bending and torsion. We simulated comminuted mid-shaft fractures by a 2 cm defect osteotomy in paired human cadaver femora. Each bone was tested intact in a Universal testing machine. The results were recorded, osteotomy and osteosynthesis were performed, and the BIC was tested. Relative stiffness was calculated for each individual bone. For P-values less than 0.01 ('least significance difference test') the difference between groups was considered to be significant. In torque testing the unslotted solid nails showed significantly more stiffness (0.6-1.8 Nm/degree) compared to the slotted nail (0.2 Nm/degree). Compared to intact bone (6.9 Nm/degree), both groups of nails were significantly less stiff (relative stiffness 2-20%). In axial load and bending testing, the large-diameter unreamed nail showed greater higher stiffness (32-68%). This study shows that stiffness of the BIC in interlocking femoral nails is more dependent on nail profile than on the press-fit of nails in the medullary canal. For torque stiffness the absence of a slot is of special importance. According to our study, all of the unslotted nails tested give adequate stability for fracture fixation. PMID:9324617

Schandelmaier, P; Farouk, O; Krettek, C; Mannss, J; Tscherne, H

1997-01-01

396

A DEM model for soft and hard rocks: Role of grain interlocking on strength  

NASA Astrophysics Data System (ADS)

The Discrete Element Method (DEM) is increasingly used to simulate the behavior of rock. Despite their intrinsic capability to model fracture initiation and propagation starting from simple interaction laws, classical DEM formulations using spherical discrete elements suffer from an intrinsic limitation to properly simulate brittle rock behavior characterized by high values of UCS/TS ratio associated with non-linear failure envelopes, as observed for hard rock like granite. The present paper shows that the increase of the interaction range between the spherical discrete elements, which increases locally the density of interaction forces (or interparticle bonds), can overcome this limitation. It is argued that this solution represents a way to implicitly take into account the degree of interlocking associated to the microstructural complexity of rock. It is thus shown that increasing the degree of interlocking between the discrete elements which represent the rock medium, in addition to enhancing the UCS/TS ratio, results in a non-linear failure envelop characteristic of low porous rocks. This approach improves significantly the potential and predictive capabilities of the DEM for rock modeling purpose. A special emphasis is put on the model ability to capture the fundamental characteristics of brittle rocks in terms of fracture initiation and propagation. The model can reproduce an essential component of brittle rock failure, that is, cohesion weakening and frictional strengthening as a function of rock damage or plastic strain. Based on model predictions, it is finally discussed that frictional strengthening may be at the origin of the brittle ductile transition occurring at high confining pressures.

Scholtès, Luc; Donzé, Frédéric-Victor

2013-02-01

397

Fluid-structure interactions in micro-interlocked regions of the cement-bone interface.  

PubMed

Experimental tests and computational modelling were used to explore the fluid dynamics at the trabeculae-cement interlock regions found in the tibial component of total knee replacements. A cement-bone construct of the proximal tibia was created to simulate the immediate post-operative condition. Gap distributions along nine trabeculae-cement regions ranged from 0 to 50.4 ?m (mean = 12 ?m). Micro-motions ranged from 0.56 to 4.7 ?m with a 1 MPa compressive load to the cement. Fluid-structure analysis between the trabeculae and the cement used idealised models with parametric evaluation of loading direction, gap closing fraction (GCF), gap thickness, loading frequency and fluid viscosity. The highest fluid shear stresses (926 Pa) along the trabecular surface were found for conditions with very thin and large GCFs, much larger than reported physiological levels (?1-5 Pa). A second fluid-structure model was created with a provision for bone resorption using a constitutive model with resorption velocity proportional to fluid shear rate. A lower cut-off was used, below which bone resorption would not occur (50 s(- 1)). Results showed that there was initially high shear rates (>1000 s(- 1)) that diminished after initial trabecular resorption. Resorption continued in high shear rate regions, resulting in a final shape with bone left deep in the cement layer, and is consistent with morphology found in post-mortem retrievals. Small gaps between the trabecular surface and the cement in the immediate post-operative state produce fluid flow conditions that appear to be supra-physiologic; these may cause fluid-induced lysis of trabeculae in the micro-interlock regions. PMID:23480611

Mann, Kenneth A; Miller, Mark A

2014-12-01

398

Techniques and accuracy of thoracolumbar pedicle screw placement  

PubMed Central

Pedicle screw instrumentation has been used to stabilize the thoracolumbar spine for several decades. Although pedicle screws were originally placed via a free-hand technique, there has been a movement in favor of pedicle screw placement with the aid of imaging. Such assistive techniques include fluoroscopy guidance and stereotactic navigation. Imaging has the benefit of increased visualization of a pedicle’s trajectory, but can result in increased morbidity associated with radiation exposure, increased time expenditure, and possible workflow interruption. Many institutions have reported high accuracies with each of these three core techniques. However, due to differing definitions of accuracy and varying radiographic analyses, it is extremely difficult to compare studies side-by-side to determine which techniques are superior. From the literature, it can be concluded that pedicles of vertebrae within the mid-thoracic spine and vertebrae that have altered morphology due to scoliosis or other deformities are the most difficult to cannulate. Thus, spine surgeons would benefit the most from using assistive technologies in these circumstances. All other pedicles in the thoracolumbar spine should theoretically be cannulated with ease via a free-hand technique, given appropriate training and experience. Despite these global recommendations, appropriate techniques must be chosen at the surgeon’s discretion. Such determinations should be based on the surgeon’s experience and the specific pathology that will be treated.

Puvanesarajah, Varun; Liauw, Jason A; Lo, Sheng-fu; Lina, Ioan A; Witham, Timothy F

2014-01-01

399

Screwing/rolling head for pre-threaded caps  

US Patent & Trademark Office Database

The present invention relates to a screwing/rolling head 1 for screwing and sealing a pre-threaded cap 5 on to a threaded neck 6 of a container 7, the head 1 having a cap pressing member 4 capable of engaging the cap 5 and screwing it on to the container 7. The said cap pressing member 4 is associated for operation with a body 2 of the head 1 in such a way that it can be moved with respect to the body 2 between a first contracted configuration and a second extended configuration, in which the movement is rotary-translational with only one degree of freedom. The present invention also relates to a head 1 in which asymmetrical clutch means 18 are interposed between the cap pressing member 4 and the body 2, and a head 1 in which the body 2 comprises a first element 8 and a second element 9 connected to it with respect to rotation by means of a disengageable torque limiter 24.

2009-11-17

400

Modelling of the Heating Process in a Thermal Screw  

NASA Astrophysics Data System (ADS)

The procedure of separating efficiently dry-stuff (proteins), fat, and water is an important process in the handling of waste products from industrial and commercial meat manufactures. One of the sub-processes in a separation facility is a thermal screw where the raw material (after proper mincing) is heated in order to melt fat, coagulate protein, and free water. This process is very energy consuming and the efficiency of the product is highly dependent on accurate temperature control of the process. A key quality parameter is the time that the product is maintained at temperatures within a certain threshold. A detailed mathematical model for the heating process in the thermal screw is developed and analysed. The model is formulated as a set of partial differential equations including the latent heat for the melting process of the fat and the boiling of water, respectively. The product is modelled by three components; water, fat and dry-stuff (bones and proteins). The melting of the fat component is captured as a plateau in the product temperature. The model effectively captures the product outlet temperature and the energy consumed. Depending on raw material composition, "soft" or "dry", the model outlines the heat injection and screw speeds necessary to obtain optimal output quality.

Zhang, Xuan; Veje, Christian T.; Lassen, Benny; Willatzen, Morten

2012-11-01

401

Determination of screw and nail withdrawal resistance of some important wood species.  

PubMed

In this study, screw and nail withdrawal resistance of fir (Abies nordmanniana), oak (Quercus robur L.) black pine (Pinus nigra Arnold) and Stone pine (Pinus pinea L.) wood were determined and compared. The data represent the testing of withdrawal resistance of three types of screws as smart, serrated and conventional and common nails. The specimens were prepared according to TS 6094 standards. The dimensions of the specimens were 5x5x15cm and for all of the directions. Moreover, the specimens were conditioned at ambient room temperature and 65+/-2% relative humidity. The screws and nails were installed according to ASTM-D 1761 standards. Nail dimensions were 2.5mm diameter and 50 mm length, conventional screws were 4x50mm, serrated screws were 4x45mm and smart screws were 4x50mm. Results show that the maximum screw withdrawal resistance value was found in Stone pine for the serrated screw. There were no significant differences between Stone pine and oak regarding screw withdrawal resistance values. Conventional screw yielded the maximum screw withdrawal resistance value in oak, followed by Stone pine, black pine and fir. Oak wood showed the maximum screw withdrawal resistance value for the smart screw, followed by Stone pine, black pine, and fir. Oak wood showed higher nail withdrawal resistances than softwood species. It was also determined that oak shows the maximum nail withdrawal resistance in all types. The nail withdrawal resistances at the longitudinal direction are lower with respect to radial and tangential directions. PMID:19325775

Aytekin, Alper

2008-04-01

402

Effect of abutment screw surface treatment on reliability of implant-supported crowns.  

PubMed

Purpose: To evaluate and compare the reliability of implant-supported single crowns cemented onto abutments retained with coated (C) or noncoated (NC) screws and onto platform-switched abutments with coated screws. Materials and Methods: Fifty-four implants (DT Implant 4-mm Standard Platform, Intra-Lock International) were divided into three groups (n = 18 each) as follows: matching-platform abutments secured with noncoated abutment screws (MNC); matching-platform abutments tightened with coated abutment screws (MC); and switched-platform abutments secured with coated abutment screws (SC). Screws were characterized by scanning electron microscopy and x-ray photoelectron spectroscopy (XPS). The specimens were subjected to step-stress accelerated life testing. Use-level probability Weibull curves and reliability for 100,000 cycles at 200 N and 300 N (90% two-sided confidence intervals) were calculated. Polarized light and scanning electron microscopes were used for fractographic analysis. Results: Scanning electron microscopy revealed differences in surface texture; noncoated screws presented the typical machining grooves texture, whereas coated screws presented a plastically deformed surface layer. XPS revealed the same base components for both screws, with the exception of higher degrees of silicon in the SiO2 form for the coated samples. For 100,000 cycles at 300 N, reliability values were 0.06 (0.01 to 0.16), 0.25 (0.09 to 0.45), and 0.25 (0.08 to 0.45), for MNC, MC, and SC, respectively. The most common failure mechanism for MNC was fracture of the abutment screw, followed by bending, or its fracture, along with fracture of the abutment or implant. Coated abutment screws most commonly fractured along with the abutment, irrespective of abutment type. Conclusion: Reliability was higher for both groups with the coated screw than with the uncoated screw. Failure modes differed between coated and uncoated groups. PMID:24818196

Anchieta, Rodolfo Bruniera; Machado, Lucas Silveira; Bonfante, Estevam Augusto; Hirata, Ronaldo; Freitas, Amilcar Chagas; Coelho, Paulo G

2014-01-01

403

The distal hindlimb musculature of the cat  

Microsoft Academic Search

Summary  Chronic recordings were made of electromyographic (EMG) activity, tension, and length of distal hindlimb muscles in six cats performing a variety of normal motor tasks. Muscles studied thoroughly or in part were medial gastrocnemius, lateral gastrocnemius, plantaris, soleus, flexor digitorum brevis, flexor digitorum longus, flexor hallucis longus, tibialis posterior, tibialis anterior, extensor digitorum longus, peroneus longus, and peroneus brevis. Postural

L. D. Abraham; G. E. Loeb

1985-01-01

404

Molar distalization with the Herbst appliance  

Microsoft Academic Search

This article reviews the dental effects of the Herbst appliance as well as itslong-term effects on the dentition. The Herbst appliance exhibits a pronounced high-pull headgear effect on the maxillary molars. Without retention, the molars tend to return to their former anteroposterior positions after the removal of the appliance. These distal movements of the maxillary molars are favorable in Class

Meson Lai

2000-01-01

405

Distal upper extremity motion during keyboarding  

Microsoft Academic Search

Abnormal computer keyboard typing patterns have been associated with musculoskeletal disorders of the upper extremities. Threshold values for quantifying abnormal distal upper extremity function during typing have been established to identify typing behaviors that may place the computer user at risk for developing an injury. In this paper, the joint displacements of repeated typing tasks were normalized using previously collected

E. J. Bill; D. R. Peterson

2007-01-01

406

Comparison of the effects of rapid maxillary expansion caused by treatment with either a memory screw or a Hyrax screw on the dentofacial structures--transversal effects.  

PubMed

The aim of the present study was to investigate and compare the effects of conventional Hyrax screw treatment and memory screw treatment on skeletal and dentoalveolar structures. Thirty-two patients with maxillary transversal deficiency were divided into two groups. The memory-screw group included 17 patients (nine females and eight males), while the Hyrax-screw group comprised 15 patients (eight females and seven males). Mean ages of the subjects in the memory-screw and Hyrax-screw groups were 13.00 ± 1.29 and 12.58 ± 1.50 years, respectively. Plaster models and postero-anterior cephalograms were taken from the patients at the beginning of the treatment (T1) and at the end of expansion (T2) and retention periods (T3). The mean expansion period was 7.76 ± 1.04 days in the memory-screw group and 35.46 ± 9.39 days in the Hyrax-screw group. 'Shapiro-Wilk Normality test' was used to determine whether the investigated parameters were homogeneous or not. To determine the treatment changes within the group, 'paired t-test' and 'Wilcoxon signed-ranks test' were applied to the homogeneous and non-homogeneous parameters, respectively. Comparison between the groups was carried out using 'Student's t-test' for homogeneous parameters and 'Mann-Whitney U-test' for the rest. Rapid maxillary expansion was carried out successfully in both the groups. However, the use of memory screw may be advantageous because it shortens the maxillary expansion period, provides additional expansion in the retention period, and generates light forces relative to the conventional Hyrax screw. PMID:21876219

Hal?c?o?lu, Koray; Yavuz, Ibrahim

2014-04-01

407

Method and apparatus for determining the preload for screws for dental implant systems  

US Patent & Trademark Office Database

A method and apparatus are provided for determining the preload in a dental implant system. The preload is determined by transmitting a sonic impulse, which is preferably an ultrasonic impulse, at a predetermined frequency to the head of the implant screw through a transducer, which may be incorporated into the head of the screw, the head of a wand which generates the sonic impulse, or the transducer and pulse-generating instrumentation may be incorporated into a torque generating instrument used to tighten the screw. The preload is determined by measuring the delay between the first and second reflections through the preloaded screw to determine a preload value and comparing that value with a pre-established baseline value for the screw, and comparing the difference with a predetermined table of values to determine the preload on the screw.

2002-03-19

408

The mechanical role of laminar hook protection of pedicle screws at the caudal end vertebra  

Microsoft Academic Search

Biomechanical studies have shown hooks to be superior to pedicle screws in pull-out, especially in osteoporosis. This study evaluates the possible increase in stiffness of pedicle screws provided by laminar hooks while applying non-destructive forces to a vertebrectomy model assembled with Compact Cotrel Dubousset (CCD) instrumentation. Synthetic vertebrae were employed in a three-level vertebrectomy model. CCD screw-based three-level constructs with

J. Y. Margulies; R. S. Casar; S. A. Caruso; M. G. Neuwirth; T. R. Haher

1997-01-01

409

Investigation of melting in a modular intermeshing co-rotating twin screw extruder  

Microsoft Academic Search

Since the first patent regarding the co-rotating twin screw extruder was published in 1869, the co-rotating twin screw extruder has evolved into a high performance extruder, having self wiping capability, modular screw configuration, starved feed zone, kneading disc block elements, and special mixing devices. For this device, flow studies began in the mid 1960's but melting studies started in the

Ho-Chul Jung

2004-01-01

410

Computer tomography assessment of pedicle screw insertion in percutaneous posterior transpedicular stabilization  

Microsoft Academic Search

Percutaneous insertion of cannulated pedicle screws has been recently developed as a minimally invasive alternative to the\\u000a open technique during instrumented fusion procedures. Given the reported rate of screw misplacement using open techniques\\u000a (up to 40%), we considered it important to analyze possible side effects of this new technique. Placement of 60 pedicle screws\\u000a in 15 consecutive patients undergoing lumbar

Constantin Schizas; Jacky Michel; Victor Kosmopoulos; Nicolas Theumann

2007-01-01

411

Accuracy and complications of transpedicular C2 screw placement without the use of spinal navigation  

Microsoft Academic Search

The objective of the study was to describe the technique, accuracy of placement and complications of transpedicular C2 screw\\u000a fixation without spinal navigation. Patients treated by C2 pedicle screw fixations were identified from the surgical log book\\u000a of the department. Clinical data were extracted retrospectively from the patients’ charts. Pedicle screw placement accuracy\\u000a was assessed on postoperative CT scans according

Christian-Andreas Mueller; Lukas Roesseler; Martin Podlogar; Attlila Kovacs; Rudolf Andreas Kristof

2010-01-01

412

Use of a 2.0-mm locking plate\\/screw system for mandibular fracture surgery  

Microsoft Academic Search

Purpose: In this study, we examined the use of a 2.0-mm locking bone plate\\/screw system in mandibular surgery. Patients and Methods: All patients who were treated with a 2.0-mm locking bone plate\\/screw system during an 8-month period for fractures of the mandible or other defects of the mandible were prospectively studied. Ease of use of locking plate\\/screw system, characteristics of

Edward Ellis; John Graham

2002-01-01

413

Use of a locking reconstruction bone plate\\/screw system for mandibular surgery  

Microsoft Academic Search

Purpose: This study examined the use of a locking reconstruction bone plate\\/screw system for use in mandibular surgery.Patients and Methods: All patients treated with a locking reconstruction bone plate\\/screw system for fractures of the mandible or continuity defects in an 18-month period were prospectively studied. Ease of use of the locking plate\\/screw system, characteristics of the fractures\\/defects, and complications were

Alan S Herford; Edward Ellis

1998-01-01

414

Proximal metatarsal osteotomy for hallux valgus: an audit of radiologic outcome after single screw fixation and full postoperative weightbearing  

PubMed Central

Background Proximal metatarsal osteotomy combined with a distal soft-tissue procedure is a common treatment for moderate to severe hallux valgus. Secure stabilisation of the metatarsal osteotomy is necessary to avoid complications such as delayed union, nonunion or malunion as well as loss of correction. The aim of this study was to report our results using a single screw for stabilisation of the osteotomy. Methods We retrospectively reviewed 151 patients with severe hallux valgus who were treated by the above mentioned way with full postoperative weightbearing in a stiff soled shoe. Mean age of patients at time of surgery was 54 years, 19 patients were male and 132 female. Assessment of clinical and radiographic results was performed after 2 days and 6 weeks. Results were also correlated to the experience of the performing surgeon. Results Mean preoperative HVA (hallux valgus angle) was 36.4 degrees, and then 3.5 degrees 2 days and 13.4 degrees 6 weeks after the procedure (p < 0.001). Mean preoperative IMA (intermetarsal angle) was 16.8 degrees, and then 6.4 degrees after 2 days and 9.8 degrees after 6 weeks (p < 0.001). Mean preoperative first metatarsal length of 56.4 mm decreased to 53.6 mm after 6 weeks. Possible non-union of the osteotomy was observed in 4 patients (2.6%) after 6 weeks. Performing residents (n = 40) operated in 65 minutes and attending surgeons (n = 111) in 45 minutes, with no significant differences in radiographic measurements between both groups. Conclusions Single screw stabilisation of proximal chevron osteotomy is a reliable method for treating severe hallux valgus deformities with satisfactory results.

2013-01-01

415

Retrograde Tibial Nailing: a minimally invasive and biomechanically superior alternative to angle-stable plate osteosynthesis in distal tibia fractures  

PubMed Central

Background Currently, antegrade intramedullary nailing and minimally invasive plate osteosynthesis (MIPO) represent the main surgical alternatives in distal tibial fractures. However, neither choice is optimal for all bony and soft tissue injuries. The Retrograde Tibial Nail (RTN) is a small-caliber prototype implant, which is introduced through a 2-cm-long incision at the tip of the medial malleolus with stab incisions sufficient for interlocking. During this project, we investigated the feasibility of retrograde tibial nailing in a cadaver model and conducted biomechanical testing. Methods Anatomical implantations of the RTN were carried out in AO/OTA 43 A1-3 fracture types in three cadaveric lower limbs. Biomechanical testing was conducted in an AO/OTA 43 A3 fracture model for extra-axial compression, torsion, and destructive extra-axial compression. Sixteen composite tibiae were used to compare the RTN against an angle-stable plate osteosynthesis (Medial Distal Tibial Plate, Synthes®). Statistical analysis was performed by Student's t test. Results Retrograde intramedullary nailing is feasible in simple fracture types by closed manual reduction and percutaneous reduction forceps, while in highly comminuted fractures, the use of a large distractor can aid the reduction. Biomechanical testing shows a statistically superior stability (p?distal tibia fractures.

2014-01-01

416

Syndesmosis screws: How many, what diameter, where and should they be removed? A literature review.  

PubMed

Although screw fixation remains the most commonly used method of syndesmosis fixation, the ideal screw size, placement, and number remain controversial. In addition, there has been debate as to whether the screw should always be removed, and a number of studies have looked at radiological and functional outcomes. In addition a number of cadaveric models have been developed, but the correlation between cadaveric findings and functional outcomes remains unclear. This systematic review of the literature aims to summarise the available evidence on how many screws should be placed, of what diameter, through how many cortices, at what level, and whether they should be removed. PMID:24917210

Peek, A C; Fitzgerald, C E; Charalambides, C

2014-08-01

417

Development and Testing of a Screw Compressor Supermarket Refrigeration System: Phase II, Final Report.  

SciTech Connect

A laboratory prototype screw compressor refrigeration system was designed, fabricated and tested under various evaporator and ambient conditions. The design is based on a Dunham-Bush vertical hermetic screw compressor and other standard refrigeration components. Results indicate that a screw compressor rack with vapor injection can increase the thermodynamic efficiency of low temperature refrigeration in supermarkets by 20 to 28% compared to multiple reciprocating compressor racks. The payback period of the screw compressor refrigeration system relative to multiple reciprocating compressor systems is 1.1 to 1.5 years and the net present value savings range from 15 to 22 thousand dollars.

Borhanian, H. Hamed; Toscano, William M.; Lee, Kang P.

1987-02-01

418

CALAXO(R) Osteoconductive Interference Screw: The Value of Post-Market Surveillance  

PubMed Central

The CALAXO® osteoconductive interference screw was recalled in August 2007 due to reports of increased numbers of postoperative complications associated with screw swelling and prominence leading to the need for surgical debridement. This study reviews complications associated with CALAXO® screw use in a consecutive cohort of patients undergoing anterior cruciate ligament reconstruction surgery by the senior author at our institution. Over a 12 month period, 226 CALAXO® interference screws, either of 20mm length or 25mm length, were implanted in 112 patients, and postoperative complications were noted. The 25mm tibial screw was over 5 times (RR 5.2, 95% CI 1.8 to 15.3) more likely to be prominent than the 20mm screw (p-value = 0.002). Four surgical debridements were required in the 25mm tibial screw group; none were required in the 20mm group. We hypothesize that the inability to bury the longer screw length into the bone tunnel is associated with postoperative complications associated with the CALAXO® screw.

Cox, Charles L.; Homlar, Kelly C.; Carey, James L.; Spindler, Kurt P.

2013-01-01

419

C2 laminar screw and C1-2 transarticular screw combined with C1 laminar hooks for atlantoaxial instability with unilateral vertebral artery injury.  

PubMed

Transarticular screw fixation (TASF) is technically demanding, with high risk of vertebral artery (VA) injury. How to manage intraoperative VA injury and choose optimal alternative fixation becomes a concern of spinal surgeons. In this study, the management strategy for a patient with suspected intraoperative VA injury was analyzed. A 53-year-old woman developed type II odontoid fracture and brain stem injury due to a motor vehicle accident 3 months earlier. After conservative treatments, the brain stem injury improved, but with residual ocular motility defect in the right eye. The odontoid fracture did not achieve fusion with displacement and absorption of fracture fragments. After admission, atlantoaxial fixation using bilateral C1-2 transarticular screws (TASs) combined with C1 laminar hooks was planed. The first TAS was inserted successfully. Unfortunately, suspected VA injury developed during tapping the tract for the second TAS. Considering the previous brain stem injury and that directly inserting the screw to tamponade the hemorrhage might cause VA stenosis or occlusion, we blocked the screw trajectory with bone wax. C2 laminar screw was implanted instead of intended TAS on the injured side. The management strategy for suspected VA injury should depend on intraoperative circumstances and be tailored to patients. Blocking screw trajectory with bone wax is a useful method to stop bleeding. Atlantoaxial fixation using C2 laminar screw and C1-2 TAS combined with C1 laminar hooks is an ideal alternative procedure. PMID:21331546

Guo, Qunfeng; Liu, Jun; Ni, Bin; Lu, Xuhua; Zhou, Fengjin

2011-09-01

420

Accuracy of Free Hand Pedicle Screw Installation in the Thoracic and Lumbar Spine by a Young Surgeon: An Analysis of the First Consecutive 306 Screws Using Computed Tomography  

PubMed Central

Study Design A retrospective cross-sectional study. Purpose The purpose of this study is to evaluate the accuracy and safety of free-hand pedicle screw insertion performed by a young surgeon. Overview of Literature Few articles exist regarding the safety of the free-hand technique without inspection by an experienced spine surgeon. Methods The index surgeon has performed spinal surgery for 2 years by himself. He performed fluoroscopy-assisted pedicle screw installation for his first year. Since then, he has used the free-hand technique. We retrospectively reviewed the records of all consecutive patients undergoing pedicle screw installation using the free-hand technique without fluoroscopy in the thoracic or lumbar spine by the index surgeon. Incidence and extent of cortical breach by misplaced pedicle screw was determined by a review of postoperative computed tomography (CT) images. Results A total of 36 patients received 306 free-hand placed pedicle screws in the thoracic or lumbar spine. A total of 12 screws (3.9%) were identified as breaching the pedicle in 9 patients. Upper thoracic spine was the most frequent location of screw breach (10.8%). Lateral breach (2.3%) was more frequent than any other direction. Screw breach on the right side (9 patients) was more common than that on the left side (3 patients) (p<0.01). Conclusions An analysis by CT scan shows that young spine surgeons who have trained under the supervision of an experienced surgeon can safely place free-hand pedicle screws with an acceptable breach rate through repetitive confirmatory steps.

Lee, Chang-Hyun; Kim, Yongjung J; Kim, Ki-Jeong; Jahng, Tae-Ahn; Kim, Hyun-Jib

2014-01-01

421

Experimental distal subluxation in the glenohumeral joint.  

PubMed

In an experimental set-up including ten shoulder specimens, increments in the acromiohumeral distance (the subacromial space) were measured on an X-ray radioscope after the vertical stabilizing structures of the glenohumeral joint had been cut. It was found that when only the supraspinatus tendons were cut, the acromiohumeral space only increased by a few millimeters. When first the coracohumeral ligament and then the proximal one-third of the anterior capsule were cut, the acromiohumeral distance was doubled in each case. Distal subluxation did not occur when only the anterior capsule was cut. When the coracohumeral ligament was also cut, the acromiohumeral distance was more than doubled. It is concluded that the most important structures in the pathogenesis of distal subluxation are first the coracohumeral ligament and then the proximal part of the glenohumeral capsule. PMID:4051701

Ovesen, J; Nielsen, S

1985-01-01

422

Peristalsis in the rabbit distal colon  

PubMed Central

1. The motility of the distal colon of the rabbit has been examined by the conventional Trendelenburg method and by an isometric, isovolumic modification of this method. 2. The colon shows a range of movements, and tetrodotoxin and cold-storage have been used in an attempt to differentiate between myogenic and neurally integrated activities. 3. The observable myogenic movements are pendulum movements, `tone rings' and `tone waves'; the last of these can be weakly propulsive. The rabbit colon also shows a neurally organized and powerfully propulsive movement which corresponds to the peristaltic wave. 4. The implication of a role for nervous structures in the propulsive activity of the rabbit distal colon is at variance with the view of Lee (1960). 5. The myenteric reflex arc in the colon has been examined pharmacologically. Cholinergic neural transmission has been implicated at the ganglionic-synaptic and neuroeffector junctions, but additional noncholinergic mechanisms of chemical transmission have not been excluded.

Mackenna, B. R.; McKirdy, H. C.

1972-01-01

423

Mini-Incision Distal Biceps Tendon Repair  

Microsoft Academic Search

\\u000a Stark first described distal biceps tendon rupture in 1843.1 The earliest reports of surgical repair was in 1897 by Johnson and later in 1898 by Acquaviva.1, 2 Fischer and Shepanek in 19563 and Meherin and Kilgore in 19604 reported on a single incision for reattachment of the biceps to the radial tuberosity. This was shown to significantly improve\\u000a flexion and

Jason A. Schneider; Peter D. McCann

424

Distal tibial triplane fractures: diagnosis with CT.  

PubMed

Distal tibial triplane features, which constitute 6%-10% of epiphyseal injuries, are most accurately delineated and analyzed with computed tomography (CT). This is directly related to the special geometry of these fractures that have important transverse components. CT, with its transaxial orientation, is the only radiographic technique that directly images the otherwise inaccessible, horizontally oriented tibial plafond, the integrity of which largely determines the prognosis. CT is the method of choice for preoperative and postoperative evaluation of these injuries. PMID:3602382

Feldman, F; Singson, R D; Rosenberg, Z S; Berdon, W E; Amodio, J; Abramson, S J

1987-08-01

425

A simple distal radioulnar joint orthosis.  

PubMed

These authors describe an orthosis they have successfully used in their clinic to treat patients with distal radioulnar joint instability. In addition to describing how they fabricate the orthosis, these authors also describe how they determine if the patient needs volar or dorsal support, and how they then incorporate this support into the orthosis - Victoria Priganc, PhD, OTR, CHT, CLT, Practice Forum Editor. PMID:23692968

O'Brien, Virginia H; Thurn, Jennifer

2013-01-01

426

Laparoscopic distal pancreatectomy with splenic preservation  

Microsoft Academic Search

Background  The technique of distal pancreatectomy has been well described, both with en bloc resection of the spleen and with splenic\\u000a preservation. Splenic preservation during pancreatic tail resection is desirable when oncologically appropriate, yet it is\\u000a technically challenging, particularly with laparoscopic approaches. Skeletonization of the splenic artery and vein is associated\\u000a with longer operative times and greater potential for bleeding. The

A. Pryor; J. R. Means; T. N. Pappas

2007-01-01

427

Floating distal interphalangeal joint injury: case report.  

PubMed

A 37-year-old man sustained a floating distal interphalangeal (DIP) joint injury to the left index finger. The diagnosis was not confirmed until 3 months after the injury because of minimal deformity of the injured finger. Open reduction and internal fixation of the dorsally displaced floating DIP joint was carried out. Bone union was achieved but radiographs revealed osteoarthritis of the DIP joint. PMID:20724082

Kawamura, Kenji; Omokawa, Shohei; Shimizu, Takamasa; Tanaka, Yasuhito

2010-09-01

428

Distal Embolic Protection for Renal Arterial Interventions  

SciTech Connect

Distal or embolic protection has intuitive appeal for its potential to prevent embolization of materials generated during interventional procedures. Distal protection devices (DPDs) have been most widely used in the coronary and carotid vascular beds, where they have demonstrated the ability to trap embolic materials and, in some cases, to reduce complications. Given the frequency of chronic kidney disease in patients with renal artery stenosis undergoing stent placement, it is reasonable to propose that these devices may play an important role in limiting distal embolization in the renal vasculature. Careful review of the literature reveals that atheroembolization does occur during renal arterial interventions, although it often goes undetected. Early experience with DPDs in the renal arteries in patients with suitable anatomy suggests retrieval of embolic materials in approximately 71% of cases and renal functional improvement/stabilization in 98% of cases. The combination of platelet inhibition and a DPD may provide even greater benefit. Given the critical importance of renal functional preservation, it follows that everything that can be done to prevent atheroembolism should be undertaken including the use of DPDs when anatomically feasible. The data available at this time support a beneficial role for these devices.

Dubel, Gregory J., E-mail: gdubel@lifespan.org; Murphy, Timothy P. [Brown University Medical School, Department of Diagnostic Imaging, Division of Interventional Radiology (United States)

2008-01-15

429

Novel topical therapies for distal colitis  

PubMed Central

Distal colitis (DC) can be effectively treated with topical 5ASA agents. Suppositories target the rectum while enemas can reliably reach the splenic flexure. Used in combination with oral 5ASAs, the control of the inflammation is even more effective. Unfortunately, resistant DC does occur and can be extremely challenging to manage. In these patients, the use of steroids, immunosuppressants and the anti-tumor necrosis factor ? agents are often required. These, however, can be associated with systemic side effects and are not always effective. The investigation of new topical therapeutic agents is thus required as they are rarely associated with significant blood drug levels and side effects are infrequent. Some of the agents that have been proposed for use in resistant distal colitis include butyrate, cyclosporine and nicotine enemas as well as tacrolimus suppositories and tacrolimus, ecabet sodium, arsenic, lidocaine, rebamipide and Ridogrel® enemas. Some of these agents have demonstrated impressive results but the majority of the agents have only been assessed in small open-labelled patient cohorts. Further work is thus required with the investigation of promising agents in the context of randomized double-blinded placebo controlled trials. This review aims to highlight those potentially effective therapies in the management of resistant distal colitis and to promote interest in furthering their investigation.

Lawrance, Ian Craig

2010-01-01

430

Distal phalangeal metastasis of extramammary Paget's disease.  

PubMed

A rare case of phalangeal metastasis of extramammary Paget's disease in a 68-year-old man is described. The patient developed an erythematous, slightly elevated area in the pubic region. A biopsy specimen demonstrated numerous, large, rounded cells with ample pale-staining cytoplasm proliferating in the epidermis. With a diagnosis of extramammary Paget's disease, he underwent wide local excision and inguinal node dissection. Eleven months postoperatively, the patient developed a tender, red, swollen right ring finger. Bone X-ray showed that the distal phalanx of the ring finger had completely dissolved. Histopathological examination demonstrated proliferation of tumor cells in the adipose tissue. They had poorer and darker cytoplasm than the Paget's cells in the epidermis of the pubic region. Immunohistochemically, these cells showed the same staining pattern as did the Paget's cells at the primary site. Accordingly, the patient was diagnosed with distal phalangeal metastasis of extramammary Paget's disease. Two weeks after the appearance of the distal phalangeal metastasis, the patient died of cancerous pleurisy. It has been reported that patients with phalangeal metastasis have a very poor prognosis. PMID:14739508

Umebayashi, Yoshihiro

2004-01-01

431

Forsok med alkolas i Sverige. Evaluering av forsoksordningen med betinget forekortinndragning ved promillekjoring (Evaluation of the trial with an alcohol ignition interlock programme in Sweden).  

National Technical Information Service (NTIS)

The trial with an alcohol ignition interlock program commenced in 1999 in three counties in Sweden. In 2003 the trial was extended to the whole country. The purpose of this project has been an independent evaluation of the trial.

K. S. Eriksen S. Nordbakke T. Assum T. Grunnan

2007-01-01

432

Tibial tubercle osteotomy with screw fixation for total knee arthroplasty.  

PubMed

This study investigated the efficacy of tibial tubercle osteotomy (TTO) with screw fixation as part of the surgical treatment of primary complicated total knee arthroplasty (TKA) and revision TKA. From January 2000 to April 2011, 15 patients (15 knees) underwent revision TKA and 20 patients (21 knees) underwent primary TKA. The average patient age was 68.7±8.7 years. Patients underwent follow-up at the authors' institution for an average of 60.6±32.9 months. Comparison of preoperative and postoperative Knee Society Scores and Knee Society Functional Scores showed significant postoperative improvement (P<.05). Moreover, postoperative range of motion of the knee improved from 88.5°±33.8° to 104.3°±18.2° (P<.05). Radiographic assessment showed that the average period to bone union was 10.8±5 weeks (range, 5-28 weeks), the average length of the bone fragment was 59.4±5.9 mm, the average width at the proximal end was 18.9±2.9 mm, and the average thickness at the proximal end of the osteotomy was 10.3±1.2 mm. Tibial tubercle osteotomy provided wide exposure for TKA while protecting the extensor mechanism. Solid bone-to-bone fixation was achieved using TTO with 2 screws, and although the overall complication rate was 8.3%, none of the complications were associated with TTO itself. It is recommended that the bone fragment be 60 mm long, 20 mm wide, and 10 mm thick at the proximal end. Appropriate size of the osteotomized bone and solid screw fixation are essential to prevent complications during this procedure. PMID:24762842

Chinzei, Nobuaki; Ishida, Kazunari; Kuroda, Ryosuke; Matsumoto, Tomoyuki; Kubo, Seiji; Iguchi, Tetsuhiro; Chin, Takaaki; Akisue, Toshihiro; Nishida, Kotaro; Kurosaka, Masahiro; Tsumura, Nobuhiro

2014-04-01

433

Atlantoaxial fixation using the polyaxial screw–rod system  

Microsoft Academic Search

The aim of this study is to evaluate the first results of the atlantoaxial fixation using polyaxial screw–rod system. Twenty-eight\\u000a patients followed-up 12–29 months (average 17.1 months) were included in this study. The average age was 59.5 years (range\\u000a 23–89 years). The atlantoaxial fusion was employed in 20 patients for an acute injury to the upper cervical spine, in 1 patient\\u000a with rheumatoid arthritis

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