Biomechanical performance of new cardiovascular needles

Cardiovascular needles are now being manufactured from new stainless steel alloys containing high concentrations of nickel, Surgalloy and Ethalloy. The purpose of this study was to compare the biomechanical performance of a cardiovascular needle made of Surgalloy with a comparably sized needle made of Ethalloy. The parameters of biomechanical performance included sharpness, maintenance of sharpness, resistance to bending, and ductility. Because the biomechanical performance of these needles was remarkably similar, cardiovascular needles made of either the Surgalloy or Ethalloy alloys are recommended for cardiovascular surgery.

Failure of glove hole detection device for synthetic gloves

Holes in latex gloves can be reliably detected by commercially available electronic devices. The purpose of this study was to compare the performance of an electronic glove hole detection device using latex gloves to that of neoprene, vinyl, and nitrile latex-free gloves. The electronic hole detection device accurately detected holes in the latex gloves during the 2-h study. In contrast, the latex-free gloves were immediately conductive of electricity in the absence of holes. Consequently, electronic glove hole detection devices cannot be reliably used with latex-free gloves.

Ease of donning commercially available latex examination gloves

There are a wide variety of latex examination gloves now available for use by health care providers. A prospective randomized trial was completed to quantify the forces required to don a sample of seven cornstarch-lubricated gloves and 13 powder-free latex examination gloves. The data collected was analyzed by a 20 x 2 general factorial ANOVA, as well as two 1-way ANOVAs using a least significance difference post hoc test. Some powder-free gloves can be easily donned with dry or wet hands without tearing with forces comparable to those encountered with powdered gloves. With the advent of these powder-free examination gloves, powdered gloves can now be abandoned, protecting health professionals and patients from the dangers of absorbable dusting powders. Despite the dangers of the absorbable dusting powders and the Food and Drug Administration's requirement for labeling examination glove boxes, some manufacturers of powdered examination gloves do not appropriately label their boxes with a warning to the health professional and patient of the presence of powder.

Biomechanical performance of orthopedic gloves

The purpose of this study was to compare the biomechanical performance of commercially available orthopedic gloves to that of a single surgical glove, as well as a double glove system. The orthopedic gloves were found to be thicker than the single surgical glove. This increased thickness of the orthopedic glove was associated with a greater resistance to glove puncture. The thickest orthopedic gloves also had reduced tactile sensitivity when compared to the single surgical glove. In addition, the glove donning forces and glove hydration rates varied considerably. These latter biomechanical performance parameters were not significantly related to glove thickness. The double glove systems tested in this study had similar performance characteristics in regard to many of the orthopedic gloves. The glove donning forces for the double glove systems were the lowest of the gloves tested. In addition, the double glove systems displayed the greatest resistance to glove hydration of the gloves tested. Their performance in the glove hydration tests and the force required to don the double glove systems were much more desirable than any of the orthopedic gloves. The results of this study indicate that the double glove systems may provide a desirable alternative to the use of the single orthopedic gloves.

Influence of irrigation solutions on oscillating bone saw blade performance

The influence of irrigation on bone cutting was determined by measuring the biomechanical performance of a bone cutting saw during irrigation with various solutions. Solutions of 0.9% saline and 10, 20, and 30% poloxamer-188 were used as the irrigant. A 10% solution of poloxamer-188 was judged to be the superior irrigant because it successfully maintained bone temperature at a controlled level without interfering with the rate of bone removal.

Wheelchair caster shimmy II: damping

The theory of shimmy damping is investigated including tire friction, spindle bearing friction, and hydraulic damping. A new theoretical improvement in hydraulic damping is presented. Experimental results are presented along with a discussion concerning the limitations due to the approximations used in the theory. The basic theory of wheelchair caster shimmy was published by the authors in 1984, and an examination of the sources of shimmy damping is corrected and updated in this paper.

Biomechanical performance of latex and non-latex double-glove systems

The purpose of this study was to evaluate ten commercially available latex, powder-free surgical gloves and four commercially available non-latex, powder-free surgical gloves using standardized, reproducible biomechanical parameters that included glove thickness, puncture resistance, and glove donning force. For all gloves tested, with one exception (Neolontrade mark PF), puncture resistance increased for double-gloves as compared to single-gloves. In addition, single-glove thickness was not a reliable determinant of puncture resistance for either latex or non-latex gloves. For the latex gloves, the Ultrafree double and single-gloves exhibited the highest puncture resistance. The glove donning forces for the Biogeltrade mark M and Biogel Sensortrade mark single-gloves were the lowest. In contrast, the Biogel Revealtrade mark and Encoretrade mark Ultra-Thick exhibited the lowest double-glove donning forces. On the basis of these performance tests of latex gloves, the surgeon should consider the Biogel Reveal as well as the Ultrafree gloves for their latex double-glove system. For the non-latex gloves, the Pure Advantage Nitriletrade mark glove had the highest puncture resistance for one layer and two layers of glove material. The thin Pure Advantage Nitrile glove was the most resistant to glove puncture. The Pure Advantage Nitrile glove had low glove donning forces for both single-glove donning configurations and double-glove donning configurations. Consequently, we recommend the Pure Advantage Nitrile glove as the powder-free, non-latex, double-glove system.

Biomechanical performance of powder-free examination gloves

Biomechanical performance studies were undertaken for powder-free, latex and nitrile examination gloves. Using standardized tests, examination glove performance was judged by measuring glove thickness, glove puncture force, glove tape adhesion force, glove donning force, glove stiffness, and immediate unrecovered stretch. Even though the nitrile examination gloves were thinner than the latex examination gloves, they exhibited a greater puncture resistance. In addition, tape adherence to the N-Dex nitrile glove was the lowest. Moreover, measurements of the handling characteristics of the nitrile examination gloves demonstrated that they are an acceptable alternative to latex examination gloves. While these biomechanical studies demonstrate the superiority of the nitrile examination gloves, clinical glove evaluation is still needed to determine their performance in the health care setting.

Biomechanical performance of examination gloves

The purpose of this study was to compare the biomechanical performance of new powder-free commercially available synthetic examination gloves to that of commercially available powder-free latex examination gloves. The synthetic gloves were significantly thinner than the latex gloves. Despite the decreased thickness, all three nitrile gloves, as well as the polyvinyl chloride glove, exhibited a greater resistance to glove puncture. The glove donning forces varied considerably among all gloves, and wet donning forces were greater than dry donning forces. Under dry conditions, the donning forces for the synthetic gloves were less than or equal to the forces for the latex gloves. Because of their increased puncture resistance and similar donning forces, synthetic gloves are a safe alternative to latex examination gloves.

A synthetic membrane for testing needle penetration

Needle performance is primarily judged by its penetration through tissue. For detailed studies of needle performance, tissue is too heterogeneous and unstable and difficult to obtain. A homogeneous, stable, and readily available polyurethane substrate has been evaluated as a suitable alternative to biological tissue for evaluation of needle penetration. The needle penetration profiles through the synthetic substrate correlated very well with those through natural tissue. In addition, the synthetic substrate was sensitive enough to easily detect a 20% increase in the force necessary to penetrate natural tissue. This polyurethane substrate offers a valid alternative to biological tissue for the testing of needle penetration performance.

Influence of surgeon's tying technique on knot security

The purpose of this study was to determine the influence of the surgeon's tying technique on knot security using 0 and 2-0 monofilament and multifilament nylon sutures. Using an Instron Tensile Tester and a portable tensiometer, knot security was achieved with these sutures using four-throw square knots (1 = 1 = 1 = 1). After didactic and psychomotor skill training, medical students were taught to construct the four-throw square knot using either a two-hand tie or an instrument tie. Using the portable tensiometer, their knot tying techniques were judged to be superior to those used by surgeons. The surgeon's faulty technique can easily be corrected by didactic information and psychomotor skill training.

Inadequate standard for glove puncture resistance: allows production of gloves with limited puncture resistance

The National Fire Protection Association has developed standards for glove puncture resistance using a metal puncture probe. Biomechanical performance studies have demonstrated that glove puncture resistance to the probe is significantly greater than that of the hypodermic needle, suggesting that these standards have no clinical relevance. These standards give a false sense of security to health care personnel and sanction the production and use of gloves that give inadequate protection. The result is potentially harmful for medical personnel.

A new computerized control unit for small bone surgical instruments

The SmartDrive console represents an important advance in small bone surgery because it monitors and coordinates the operation of its handpieces. The SmartDrive console has the following unique features: 1) a handpiece recognition system; 2) an instrument speed display; 3) a handpiece display and monitoring system; 4) a torque instrument control system; 5) a temperature monitoring system; 6) and an irrigation system. Mechanical performance studies have been undertaken that have validated the accuracy of the monitoring systems of the consoles. The consoles provided reliable recordings of the rotational speeds of their hi-speed drills. The MicroAire console automatically shuts off its power as the temperature increased to 110 degrees F (43 degrees C). In contrast, the Stryker Command 2 console has a limited monitoring system that can not alter the operation of the handpieces.

Biomechanical performance of cutting edge surgical needles

The purpose of this study was to compare the biomechanical performance of cutting edge needles made of S45500 stainless steel alloy to Surgalloy stainless steel. The new high-nickel stainless steel alloy, Surgalloy, has superior performance characteristics over that of the other high-nickel stainless steel alloy, S45500. The Surgalloy needle is produced from a stronger stainless steel alloy than the S45500 needle. The Surgalloy needle has considerably greater resistance to bending than the needle produced from S45500 alloy. In addition, Surgalloy stainless steel has almost a twofold greater resistance to fracture than the S45500 stainless steel alloy.

A technique for quantifying the performance of oscillating bone saw blades

A new model has been developed to evaluate the performance of oscillating surgical saw blades used in medical-implant procedures. A test apparatus was constructed to maintain a constant cutting force between a blade driven by a pneumatic powered oscillating saw and the bone. Evaluations of saw-blade performance were determined using the following outcome measures: cutting time, volume of bone removal, and peak cutting temperature. Two popular, commercially available blades similar in size and tooth geometry were evaluated. This model identified differences in the performance of these two types of oscillating saw blades.

Durability of oscillating bone saw blades

The purpose of this study was to measure the durability of disposable saw blades using a standard bone-cutting experimental model that can be replicated in any laboratory. Using a constant cutting force, the bone-cutting efficiency was determined by recording the maximum cutting temperature and the rate of material removal. In this experimental study, porcine femurs as well as a synthetic bone substitute were used as the test samples for measuring cutting efficiency. Repeated cutting of these test materials did not significantly alter the performance of the disposable bone-cutting blades.

Innovations in oscillating bone saw blades

The purpose of this study was to identify some of the determinants of saw-blade design that influence bone-cutting performance. Using a reproducible experimental model, saw-blade performance was judged by measuring the blade temperature and the rate of bone removal. The results of this study demonstrated that the rake angle and blade swing radius had significant influence on saw-blade performance.

Another cause of surgical needle holder damage to surgical sutures

The sharp edges of the box lock of the needle holder can inadvertently damage the suture during instrument ties. Compression of a monofilament nylon suture between the sharp edges of the box lock of a surgical needle holder damages the suture, reducing its breaking strength. This adverse effect has been eliminated by one manufacturer whose needle holder box lock has rounded edges and sufficient space to permit passage of the suture.

Needle puncture resistance of surgical gloves, finger guards, and glove liners

New puncture resistant materials are being developed for health professional use as protection against disease and needle stick injuries. The needle puncture resistance of protective gloves and glove liners from DePuy DuPont Orthopaedics and of finger guards from Zimmer was evaluated using a computerized needle penetration system to determine maximal penetration forces and the penetration work required for taper point and for cutting edge needles to penetrate these membranes. The Medak portion of the Life Liner glove liner and the Spectra portion of the FingGuard finger guard offered remarkable resistance against needle penetration as compared to the other glove liners and gloves tested. The cutting edge needles required considerably less penetration force and work to penetrate the FingGuard and Life Liner than that required with comparable size taper point needles. Because these unique protective materials had a limited distribution over the hand, the surgeon's hand remained susceptible to inadvertent needle puncture. While this protection against needle penetration in the Life Liner and the FingGuard represents an exciting advance in surgery, it is important to emphasize that this development is only one consideration in the selection of surgical gloves.

Knot performance of polypropylene sutures

A mechanical performance test using an Instron Tensile Tester demonstrated the superior handling characteristics of Surgipro suture as compared to Prolene suture that facilitated knot construction without suture breakage. For both granny and square knots, the knot run down forces for the Surgipro sutures were significantly less than those encountered for comparable knots for Prolene sutures. This propensity of the two-throw knots of Surgipro sutures to advance without breakage considerably facilitated knot construction.

Studies of determinants of glove hole puncture during electrosurgery

Holes in surgical gloves are considered to be an important source of transmission of pathogens between patient and surgeon. The purpose of this study was to determine if electrosurgery could alter the integrity of latex surgical gloves. The effects of electrosurgery on 11 brands of commercially available latex surgical gloves were tested through an in vitro study that simulated the conditions in the operating room. Glove hole puncture was encountered only with coagulation current operating at the highest setting. In addition, maximal surface area contact with the hemostat to the glove surface was required to produce glove puncture. The presence of powder and glove hydration were not significant determinants of glove hole puncture. On the basis of our study, we believe that all surgical gloves tested offered the surgeon adequate protection at commonly used levels of cutting and coagulation current, as long as no breach existed prior to the donning of gloves.

Ease of donning commercially available powder-free surgical gloves

There are a wide variety of powder-free gloves that can now be used by surgeons. The purpose of this study was to quantify the forces required to don these powder-free surgical gloves. The lowest donning forces for wet hands was encountered with powder-free gloves coated with a hydrogel polymer. In addition, the hydrogel coated gloves exhibited the least increase in donning forces from dry hands to wet hands. While greater forces were encountered with the other commercially available powder-free gloves than the hydrogel coated gloves, they all could be safely donned on dry hands without tearing.

Strain-based fatigue analysis of wheelchairs on a double roller fatigue machine

Results are presented from an experimental program that recorded the outputs of strain gages mounted on two wheelchair frames (one manual, one power) as the wheelchairs were run on a double roller fatigue machine. Rectangular strain gage rosettes were attached to the frames near the cross tube center pin and on the side frame behind a front caster. Thirty data sets were recorded from each rosette on each wheelchair frame. The fatigue test machine and test protocol were in substantial conformance with the recently published ANSI/RESNA Standard for wheelchair fatigue testing. Two analyses have been performed on the recorded strain data. The von Mises stress histories were computed from the strain data and show that peak stresses are frequently twice the mean value. Also, estimates of the number of fatigue machine cycles to failure have been made using a strain-based fatigue analysis. These data will provide wheelchair designers with useful data to incorporate into their design process.

Successful excision of a giant acoustic neuroma in the third trimester of pregnancy

Intracranial neoplasms presenting during pregnancy are uncommon. We report the case of a woman with a giant acoustic neuroma, presenting with hyperemesis gravidarum, and detail the surgical excision of the tumour during the third trimester. The case illustrates the unusual presentation and that such surgery can be performed safely without detriment to mother or fetus.

Enhancing needle durability by silicone coating of surgical needles

The purpose of this study was to assess the effect of coating surgical needles with silicone on their durability. Needle durability is a measure of needle sharpness after repeated passage through tissue. Needle sharpness was determined by quantitating the energy required to pass a designated needle repeatedly (20 times) through porcine skin, linea alba, colon, and aorta. The results demonstrate that the durability and sharpness of silicone-coated needles were significantly greater than those of comparable uncoated needles in linea alba, colon, and aorta, but not in skin.

Ease of donning surgical gloves: an important consideration in glove selection

It is a commonly held belief among physicians that powder free surgical gloves are more difficult to don than cornstarch powdered gloves. This difficulty is supposedly enhanced when the physician's hands are wet, a situation commonly encountered when regloving during surgical procedures. This investigation dispels these beliefs by demonstrating that the forces required to don powder free gloves do not differ significantly from those required to don gloves coated in cornstarch lubricant. Moreover, Biogel, a new powder free glove with an inner hydrogel lining, is shown to don easily and safely without ripping, even with wet hands, a circumstance not encountered with other gloves.

A new powder-free glove with a textured surface to improve handling of surgical instruments

A latex surgical glove has been designed to have a textured surface that stimulates the surface of intact skin. This textured surface enhances security of grasp of surgical instruments under wet and dry conditions without altering tactile discrimination. The unique hydrogel polymer of this glove allows the glove to be donned with either wet or dry hands without the use of cornstarch lubricants.

A new glove puncture detection system

A new glove detection system has been developed for early and accurate detection of a hole in the glove. It consists of an inner glove colored by a green dye and outer glove. When a breach in the outer glove occurs, the inner glove develops a dark patch around the needle puncture hole, a visible indicator for immediate glove change. Using a computerized needle penetration system, the immediate and maximal penetration forces as well as the work required for needle penetration of this new double glove was significantly greater than those encountered with either the inner or outer glove tested separately. In addition to hole detection, this double glove provides increased protection against needle penetration.

Innovations in the design and performance of underpads for patients with burns

The purpose of this study was to determine the biomechanical performance of commercially available underpads and bed linens to reduce the development of pressure sores in patients with burns who are at high risk. The three biomechanical performance parameters examined were coefficient of friction, absorbent capacity, and rewet. Because wetting either cotton or cotton/polyester bedsheets markedly increases their coefficients of friction, underpads should be used routinely to protect the skin against frictional forces. One disposable underpad is ideally suited to protect the skin of the patient at high risk. It has a polyolefin backing with a low coefficient of friction that serves as an effective barrier to moisture transmission while still shifting easily with the patient's movement. In addition, it is the only underpad studied that contains a superabsorbent polymer that provides a far superior absorbent capacity and minimizes rewet. Wet-back is further inhibited by its thick intermediate tissue layer and its spunbonded polypropylene coverstock.

Evolution of powered surgical instruments

The history of powered surgical instruments has paralleled their need in surgery, particularly surgery involving hard tissue like bone or teeth. This development was of great importance, as the sophistication of procedures became more demanding, requiring the use of implants. The fields of neurosurgery, orthopaedics, otology, and dentistry have all played key roles in the development of the high-powered surgical instruments that are now used in every surgical and dental subspecialty. Power modalities that include pneumatic and electric sources along with the development of interchangeable accessories have revolutionized the surgical field, making procedures both safer and faster. Many physicians, dentists, and companies continue to contribute to this exciting and rapidly evolving industry.

Wound cleansing by irrigation for implant surgery

Wound irrigation is an adjunct to all implant surgeries involving surgical incisions or arthroplasties. An understanding of the physics of wound irrigation provides a scientific basis for recommending wound irrigation systems for implant surgery. When inserting implants through surgical incisions, a low-pressure irrigation system is recommended for removing blood from the wound surface. In contrast, high-pressure irrigation systems are indicated to cleanse the intramedullary canal before cemented arthroplasty. With the advent of static and dynamic pressure transducers, irrigation systems can now be specifically designed to achieve these goals.

Adaptive air travel transportation systems for persons with disabilities

The Air Carrier Access Act ensures that no air carrier may discriminate against persons with disabilities. This Act specifies rules and regulations that remove architectural barriers to persons with disabilities. Other important considerations in the comprehensive adaptive air travel system for persons with disabilities include (1) aircraft boarding environment, (2) boarding chairs, (3) collapsible aircraft wheelchairs, (4) aircraft stowage procedures for battery-powered wheelchairs, and (5) airport shuttle bus or van service. Educational curricula must be developed that describe the comprehensive operation of this system. Evaluation of the performance of the system for persons with disabilities is mandatory to ensure that persons with disabilities have the same level of services as those without disabilities.

Some biomechanical considerations in microsutures

The purpose of this study was to measure the biomechanical performance for commercially available microsutures, nylon polypropylene, polyester, and polyglactin 910. The biomechanical performance was determined by reproducible, biomechanical parameters that included stiffness, elasticity, resistance to creep, secure knot construction, and knot breaking strength. On the basis of these comprehensive studies, the handling characteristics of the nylon microsutures were judged to be superior over the other microsutures. Knot security was achieved with a three-throw square (1 = 1 = 1) knot that allowed a preview of the ultimate apposition of the divided tissue. In addition, nylon microsutures were more supple than the other microsutures. The breaking strength of the knotted nylon microsutures was comparable with those of the knotted polyglactin 910 and polyester microsutures, and significantly greater than that of the knotted polypropylene sutures. Its resistance to creep was significantly greater than that of the polypropylene microsutures but less than those of polyglactin 910 and polyester microsutures.

Biomechanics of surgical glove expansion

The purpose of this study was to correlate the latex gloves' susceptibility to hydration to its development of glove expansion or irreversible elongation of the latex glove. During hydration, the Micro-Touch glove exhibited significantly more creep strain than did the Biogel gloves. Similarly, the Micro-Touch glove exhibited glove growth, while the Biogel glove maintained a uniform fit during hydration.

Past, present, and future for surgical needles and needle holders

During the last two decades, major advances in surgical needle and needle holder technology have markedly improved surgical wound repair. These advances include quantitative tests for surgical needle and needle holders performance, high nickel maraging stainless steels, compound curved needles, needle sharpening methods, laser-drilled holes for swages, needle:suture ratios of 1:1, and the atraumatic needle holder.

New advances in automatic disposable rotating cartridge skin staplers

This report describes the design, operation, and mechanical performance of Auto Suture Multifire Premium disposable skin staplers and staples in a biomechanical laboratory investigation and a clinical evaluation. The performance of this reloadable stapler has been compared with that of a new disposable skin stapler with a rotating cartridge, the Proximate RH stapler. The latter exemplifies a disposable skin stapler whose cartridge cannot be reloaded. The Auto Suture Multifire Premium disposable skin stapler has been designed so that its cartridge can be reloaded during a single surgical procedure. The most obvious advantage of this new device is that it substantially reduces the cost of skin stapling during surgery. Another unique benefit of this stapler is that it can accommodate either regular or wide staples, allowing the surgeon to use both size of staples without discarding the stapler. On the basis of this investigation, the Auto Suture Multifire Premium disposable skin stapler is recommended for skin incision and graft closure, since it provides maximal visualization of the wound as well as the staple during its formation. It delivers the staple into the skin or skin graft so that the topspan of the staple is above the skin or wound surface. In addition, the Auto Suture Multifire Premium disposable skin stapler has a prepositioning (precocking mechanism) that is controlled by the surgeon with minimal force, a mechanism which allows the stapler to hold its staple securely, even when its pointed legs extend beyond the delivery end of the stapler. The force required to form its staples is so low that the surgeon can staple repetitively without fatigue.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical performance of microsurgical spatula needles for the repair of nail bed injuries

The purpose of this study was to determine the mechanical performance of microsurgical spatula needles for repair of nail bed injuries. Standard biomechanical tests have been devised to evaluate the performance of microsurgical spatula needles. Two comparable groups of microsurgical spatula needles were selected from two different manufacturers for these biomechanical studies. The results of this testing demonstrated that needle point geometry and needle composition were important determinants of needle performance. When needles of comparable size were evaluated, the biomechanical performance of the CS160-8 spatula needle (Ethicon, Inc., Somerville, NJ) was superior to the C-5 spatula needles (Alcon, Inc., Fort Worth, TX). While the development of these biomechanical tests has allowed the evaluation of these microsurgical spatula needles, these same tests can be used to assess the performance of new microsurgical spatula needles.

New, innovative packaging system for surgical sutures and needles

A new, innovative packaging system for surgical needles and sutures has been developed that meets the special needs of emergency physicians, surgeons, and operating personnel. This packaging system consists of an overwrap, or breather pouch, as well as an innerwrap containing the needle swaged to a surgical suture. The flaps of the overwrap are offset and serrated to facilitate the opening and sterile transfer of the inner packet to the sterile field. The inner packet contains either a plastic labyrinth or craft board that maintains the suture as straight as possible until knot construction. The needle swaged to a suture is parked in foam to protect its sharp cutting edges and point.

Biomechanical performance of laser-drilled and channel taper point needles

The purpose of this study is to evaluate the biomechanical performance of laser-drilled and channel needle swages. The laser-drilled swages have a more uniform circumference that encounters lower drag forces than the channel needle swages. In addition, the length of the laser-drilled hole is shorter than that of the channel needles, allowing the physician to grasp the laser-drilled needle close (3 mm) to the needle end without deformation. These benefits of laser-drilled swages indicate that they should replace all channel needles.

Influence of emergency physician's tying technique on knot security

The purpose of this study was to determine the influence of emergency physician's tying technique on knot security using 2-0 and 4-0 monofilament and multifilament nylon sutures. Using an Instron Tensile Tester and a portable tensiometer, knot security was achieved with these sutures using four-throw square knots (1 = 1 = 1 = 1). After didactic and psychomotor skill training, medical students were taught to construct the four-throw square knot using either a two-hand tie or an instrument tie. Using the portable tensiometer, their knot tying techniques were judged to be superior to those used by emergency physicians. The emergency physician's faulty technique can easily be corrected by didactic information and psychomotor skill training.

Biomechanical performance of ophthalmic surgical needles

The mechanical performance of ophthalmic surgical needles is studied. Standard biomechanical tests, devised to evaluate the performance of ophthalmic surgical needles, are presented. Four comparable groups of ophthalmic surgical needles were selected from two different manufacturers for these biomechanical studies. The results of this testing demonstrate that needle point geometry and needle composition are important determinants of needle performance. When comparable size needles were evaluated, the biomechanical performance of the recently introduced CS160-6 ophthalmic needle (Ethicon, Inc) was superior to the AU-5, CU-5, and SU-5 needles (Alcon, Inc). Whereas the development of these biomechanical tests has allowed the evaluation of these ophthalmic needles, these same tests can be used to assess the performance of other new ophthalmic surgical needles.

Biomechanics of a new atraumatic surgical needle holder

It is the purpose of this report to design, develop, and evaluate a needle holder whose jaws improve needle-holding security without altering the geometry of the curved surgical needle. The configuration of the jaws of this new needle holder is curved, conforming to the curvature of the surgical needle. A biomechanical study of this curved surgical needle holder demonstrates that it holds the curved needle securely without needle deformation.

A new compound-curved needle for microvascular surgery

A new compound-curved needle has been designed and developed for microvascular surgery from a unique stainless steel alloy, American Society for Testing Materials 45500. This needle has two distinct radii of curvature and a short tapered point, followed by a curved distal section. Despite its geometry, it exhibits similar resistance to bending and breakage as a curved needle with a single radius of curvature manufactured from the same alloy. The design of this new needle enables plastic surgeons to pass it through vessel walls with greater accuracy to a controlled depth and length of bite than a curved needle with a single radius of curvature.

Biochemical performance of tapercut cardiovascular needles

Standardized reproducible tests have been developed to determine the biomechanical performance of cardiovascular needles. The parameters used to assess performance were: 1) sharpness, 2) resistance to bending, and 3) ductility. Four comparable groups of tapercut and taper point cardiovascular needles were selected from different manufacturers for these biochemical studies. The results of this testing demonstrated that needle geometry, needle composition, and the manufacturer were important determinants of needle performance. When comparable needles were evaluated, the biochemical performance of cardiovascular needles manufactured by Ethicon, Inc. (Somerville, NJ) were superior to needles produced by other manufacturers. The superior performance characteristics of the cardiovascular needles produced by Ethicon, Inc. were related to their unique stainless steel alloy, American Society for Testing Materials 45500, which has greater yield and tensile strengths than the alloy used by the other manufacturers. This stainless steel alloy was ideal for the production of tapercut needles, which combined some of the features of a reverse cutting edge needle and taper point needle. Its very short cutting edges allowed it to penetrate the membrane at considerably lower penetration forces than were encountered with comparable taper point needles. In addition, the investigation indicated that the trocar point cardiovascular needles produced a large triangular defect whose diameter was much larger than that of the needle body. For this reason, the use of the trochar point needle is not recommended in cardiovascular surgery.

Influence of knot configuration and tying technique on the mechanical performance of sutures

The purpose of this investigation was to determine the influence of knot configuration and tying technique on the mechanical performance of surgical sutures. Multifilament and monofilament nylon sutures were selected for this evaluation because they are commonly used in wound closure. The mechanical performance of these sutures was judged by the following parameters: knot breakage force, configuration of secure knots, and knot run down force. During each test, tension was applied at either rapid or slow rates, which correlates with the physician's speed of tying knots. On the basis of these mechanical performance tests, four throw square (1 = 1 = 1 =1) knots and five throw square (1 = 1 = 1 = 1 = 1) knots are recommended for monofilament nylon and multifilament nylon sutures, respectively, in which the speed of application of forces to the knots is relatively slow. Because these tests can easily be replicated in any laboratory, manufacturers now have a scientific basis for recommending specific tying techniques for their surgical sutures.

Mechanical performance of surgical needle holders

A new quantitative measurement of surgical needle holder performance has been described that records the forces (clamping moment) applied by the needle holder jaws to curved surgical needles. This test has been used to determine the applied clamping forces of four different surgical needle holders made by one manufacturer. By relating the magnitude of the clamping moment of needle holder to the resistance to bending of curved surgical needles, we propose a new scientific basis for selecting surgical needle and needle holders for wound closure.

A system for adaptive transportation

In our society, we take for granted the ability to travel with few restrictions. For most travelers, the major factor that limits travel is cost. However, for a significant number of Americans, the phrase "freedom to travel" is meaningless. These are the physically handicapped, a group with special needs that has long been denied what every American assumes to be a natural right.

Metallurgically bonded needle holder jaws. A technique to enhance needle holding security without sutural damage

A new needle holder jaw face has been specifically designed and developed to increase needle holding security without sutural damage. Tungsten carbide particles have been metallurgically bonded into the stainless steel jaw to create a fine granular surface. This bonded jaw enhances needle holding security by limiting either twisting or rotation of the clamped needle. In addition, compression of the monofilament synthetic sutures by the bonded jaws does not reduce suture breaking strength.