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Biomedical subjects

R F Edlich

Publications and source records attributed to R F Edlich.

At least 37 records · Page 2Linked to original sources

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.

Biomechanical Phenomena

A new device for securing meshed split-thickness skin grafts.

This report describes the design, operation, and biomechanical performance of the Auto Suture Multifire Graftac-S disposable surgical staplers and absorbable tacks. The performance of this reloadable stapler has been compared to that of the Auto Suture Multifire Premium disposable skin stapler. The Premium stapler forms stainless steel staples to close the wound. The Graftac-S ejects absorbable tacks into the graft from a cartridge, which can be reloaded during a single operation. In two clinical trials of 10 patients each, the Graftac-S delivered absorbable tacks which were biocompatible and successfully secured the graft to the wound. The most obvious advantage of this device is that it obviates the need to remove the staples from the wound later. By the tenth postoperative day, about 90% of the tacks had extruded spontaneously, thereby reducing the amount of postoperative care required; discomfort to the patient during removal of the stainless steel staples is eliminated.

Biocompatible Materials

Modern concepts of packaging surgical needles and suture.

A new, innovative packaging system for surgical needles and sutures has been developed that meets the special needs of surgical technologists. This packaging system consists of an overwrap, or breather pouch, as well as an innerwrap containing the suture swaged to a surgical needle. 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.

Drug Packaging

A portable tensiometer for assessing surgeon's knot tying technique.

The purpose of this study was to determine the influence of surgeon's tying technique on knot security using O and 2-O monofilament and multifilament nylon sutures. By use of 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. By use of the portable tensiometer, their knot tying techniques were judged to be superior to those used by a cohort of obstetricians and gynecologists. The surgeon's faulty technique can easily be corrected by didactic information and psychomotor skill training.

Suture Techniques

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)

Disposable Equipment

Electrical burn injuries of workers using portable aluminium ladders near overhead power lines.

The use of aluminium ladders around high voltage power lines has resulted in a significant number of electrical injuries and electrocutions. Workers often misjudge wire distances or lose control of fully extended ladders, thereby exposing themselves to electrocution hazard. High-voltage electrical burns of two workers using an aluminium ladder that contacted a high voltage power line are reported. The circumstances surrounding the injury, the clinical management of the case, and the methods of prevention are presented and discussed.

Accidents, Occupational

Salvage of a patient with burn inhalation injury and pancreatitis.

A multidisciplinary approach by the staffs of the Emergency Department and the Regional Burn Center saved the life of a burn patient with an inhalation injury and pancreatitis. This successful treatment is attributed to ventilatory management using fibreoptic bronchoscopy in the Emergency Department, followed by burn eschar excision with coverage by cultured skin and non-operative management of an enlarging pseudocyst by percutaneous transgastric drainage.

Adult

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.

Animals

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.

Alloys

A new compound curved tapercut needle for oral surgery.

A new compound curved tapercut needle has been designed and developed for oral mucous membrane closure from a unique stainless steel alloy, American Society for Testing Materials (ASTM) 45500. This tapercut needle has a short, relatively straight point, followed by a curved distal section. Despite its geometry, it exhibited similar sharpness as well as resistance to bending and breakage, as did the standard tapercut needle with a single radius of curvature manufactured from the same alloy. The design of this new needle enabled the surgeon to pass it through the oral mucous membrane with a greater accuracy to a controlled depth and length of bite than the standard tapercut needle with a single radius of curvature. In addition, the new needle design aids in the suturing of mucous membranes in confined spaces.

Elasticity

A new, compound-curved needle for vascular surgery.

A new, compound-curved needle has been designed and developed for vascular surgery from a unique stainless steel alloy, American Society for Testing Materials (ASTM) 45500. This needle has two different radii of curvature and a relatively straight body followed by a short, curved tapered point. Despite its geometry, it exhibits a similar sharpness, as well as resistance to bending and breakage, as did a curved needle with a single radius of curvature manufactured from the same alloy. The design of this new needle enabled the surgeon to pass it through the vessel wall with greater accuracy to a controlled depth and length of bite than the curved cutting edge needle with a single radius of curvature.

Biomechanical Phenomena

Biomechanical performance of tapercut needles for oral surgery.

A new tapercut needle has been designed and developed for closure of the oral mucous membrane in oral surgery. It is a sharp needle with short cutting edges that easily penetrates through a small needle puncture hole. It is manufactured from a unique stainless steel alloy that resists bending and fracture. Biomechanical performance tests and clinical experience confirm its superiority over the standard reverse cutting edge needle for use in oral surgery.

Biomechanical Phenomena

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.

Elasticity

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.

Humans

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.

Biomechanical Phenomena

Some biomechanical considerations of polytetrafluoroethylene sutures.

The biomechanical performance of polytetrafluoroethylene (PTFE) sutures has been compared with that of polypropylene sutures, the standard to which other sutures used in vascular and cardiac surgery are compared. The PTFE is supple and has no plastic memory, while the polypropylene suture is stiff and retains its plastic memory. In addition, the rate of creep encountered in the PTFE suture was significantly less than that of the polypropylene suture. The knotting profiles for knot security for either a square, granny, or surgeon's knot for polypropylene sutures were three throws each. In contrast, knot security with either a square or granny PTFE knot was accomplished with seven throws; six throws were needed for a secure surgeon's knot. The breaking strength of the unknotted and knotted PTFE sutures was approximately one half as great as that for the unknotted and knotted polypropylene sutures. Knot construction significantly reduced the breaking strength of polypropylene sutures but did not alter the breaking strength of PTFE sutures. The percent elongation experienced by both sutures before breakage did not differ significantly. The elasticity, as measured by work recovery, for the polypropylene suture was greater than that for the PTFE suture. On the basis of its unique biomechanical performance characteristics, the PTFE suture should have an important place in vascular and cardiac surgery.

Physical Phenomena