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Biomedical subjects

G T Rodeheaver

Publications and source records attributed to G T Rodeheaver.

At least 55 records · Page 3Linked to original sources
PubMed1994

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↗
PubMed1993

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.

Animals↗
PubMed1993

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.

Clinical Competence↗
PubMed1993

Development of independent vessel security after ligation with absorbable sutures or clips.

The external jugular vein and the contralateral carotid artery in each of 59 rabbits were ligated with either sutures or absorbable clips and then divided. After 0, 1, 2, 4, 7, or 14 days following ligation, the suture or clip was removed, and the vessel's resistance to leakage was quantitated. When the absorbable clips were removed from arteries after 1 day, their mean resistance pressure prior to leakage was 171 +/- 46 mm Hg; in contrast, arteries ligated with a suture did not achieve independent security until after 4 days. At 4 days, the mean pressure prior to leakage of arteries with the suture removed was only 88 +/- 49 mm Hg. Similar results were obtained with veins. The difference in vessel security was attributed to the significant increase in the width of the vessel wall compressed when an absorbable clip was utilized compared with a strand of suture.

Animals↗
PubMed1993

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↗
PubMed1993

Quantitative monitoring of capsular contraction around smooth and textured implants.

The purpose of this study was to assess the efficacy of textured silicone implants in reducing the incidence of capsular contracture. Each of 10 female New Zealand, albino rabbits received 2 saline-filled implants, 1 on either side of the lateral chest wall. The surface of 1 implant was smooth silicone, whereas the other implant's surface was textured silicone. Magnetic resonance imaging (MRI) scans of the implants were performed at 0, 9, 17, 26, 34, and 40 weeks after implantation. Data from the MRI scans were used to calculate the effective surface area of implants at each analysis interval. This technique provided a noninvasive method of monitoring implant contraction as a function of time. Eight rabbits completed the study. Four of 8 smooth implants developed contractures, whereas none of the textured implants developed contracture. For the 4 smooth implants that developed contractures, MRI scans calculated 72 +/- 12% contraction at 17 weeks, but the Baker palpation test detected only mild firmness. From 17 to 40 weeks, the mean percentage of contraction for these implants changed minimally, but their mean Baker score increased from mild to severe (II to IV). Quantitative data from MRI scans were much more predictive of final implant contraction than palpation (Baker test), applanation tonometry, or indentation tonometry. The latter two tests only detected the final stages of severe implant contraction.

Animals↗
PubMed1992

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↗
PubMed1992

Early tissue reaction to textured breast implant surfaces.

Capsular contracture around breast implants with smooth surfaces continues to be an unpredictable complication. Some surgeons believe that silicone implants covered with porous polyurethane foam have a lowered potential to contract. These textured implants are not as biocompatible as silicone. Recently, silicone implants with textured surfaces have been introduced with the hope that the incidence of unacceptable implant contracture will be reduced. Using a rat implant model, the tissue reaction to textured implant surfaces was assessed. The implant surfaces evaluated were Silastic II, Siltex, MISTI, Biocell, Silastic MSI, and Même. Disks of each implant material were implanted under the dorsal skin of rats for a period of 28 days. Each implant with its surrounding tissue was excised, processed for histological analysis, and assessed for the tissue's response to the implant with particular emphasis on the formation of a continuous collagen capsule. The results indicated that the magnitude of surface texturing influenced the development of a complete capsule. Implant surfaces with a texture of less than 150 microns in height or depth (Silastic II, Siltex, and MISTI) resulted in the formation of complete capsules. An implant (Biocell) with irregular texturing (200-350 microns) produced an organized capsule over most of its surface with localized interruptions of the capsule at the sites of its deepest cavities. Implant surfaces with texturing that exceeded 350 microns in height or depth (Silastic MSI and Même) resulted in inhibition of the formation of a continuous capsule during this 28-day study.

Adipose Tissue↗
PubMed1990

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↗
PubMed1990

Scientific basis for selecting staple and tape skin closures.

Use of tape and skin staples has many important clinical applications for surgical wounds. During the past two decades, our research program has identified the optimal performance parameters of these wound closure devices. On the basis of their unique performance characteristics, specific staplers and tapes are recommended for wound closure. The scientific basis for selecting staples and tapes for wound closure is based on their influences on the biology of wound repair and infection.

Bandages↗
PubMed1990

Scientific basis for selecting surgical needles and needle holders for wound closure.

Standardized reproducible tests have been devised to determine surgical needle sharpness, resistance to bending, and ductility. Three comparable groups of reverse cutting edge needles were selected from different manufacturers for measurement of these needle performance parameters. This testing demonstrated that needle diameter, manufacturing process, needle material composition, cross-sectional design, and the manufacturer were all important determinants of surgical needle performance. In addition, the biomechanics of curved surgical needle bending has been related to the clamping moment of surgical needle holders. This relationship identifies the surgical needle holder that can be used with surgical needles without deformation. The results of these studies provide a scientific basis for the selection of surgical needles and needle holders for use in surgery.

Equipment Design↗
PubMed1989

The effect of new monofilament absorbable sutures on the healing of musculoaponeurotic incisions, gastrotomies, and colonic anastomoses.

The purpose of this study was to quantitate the effect of two new synthetic monofilament absorbable sutures, Maxon and PDS, on the healing of musculoaponeurotic incisions, gastrotomies, and colonic anastomoses. Wound healing was assessed by measuring the resistance of the closed wound to leak or burst with controlled infusion of fluid. Bursting strength measurements of these incisions were compared with those undertaken in age-weight matched controls without wounds to determine the rate of gain of wound strength. The bursting strength measurements of unwounded tissue was found to vary according to the age, weight, and specific tissue. As the animals gained weight over 42 days, the bursting strength of their colons and musculoaponeurotic tissues significantly increased. In general, the regain of prewounding bursting strength was inversely proportional to the bursting strength of the unwounded tissue. The bursting strength of abdominal musculoaponeurotic tissue was the highest, followed by the stomach and then the colon. The time intervals in which the wounded musculoaponeurotic tissues, gastrotomies, and colonic anastomoses regained the strength of the unwounded tissue was 42, 14, and 7 days, respectively. The performance of Maxon and PDS sutures in the musculoaponeurotic tissues, gastrotomies, and colonic anastomoses was similar.

Abdominal Muscles↗
PubMed1989

Biomechanics of curved surgical needle bending.

Because needle bending resistance is such an important factor in the selection of surgical needles, a standard quantitative test of needle bending has been devised to study the biomechanics of deformation of needles from three different commercial manufacturers. The superior resistance to deformation of needles made by one manufacturer has been related to the specific alloy, ASTM 45500 stainless steel, employed in its production. The needles produced from ASTM stainless steel 45500 have stronger tensile and yield strengths than those of the other alloys, accounting for their greater resistance to bending.

Alloys↗
PubMed1989

Surgical needle sharpness.

We developed a standard reproducible test to determine surgical needle sharpness. This parameter was measured by recording the maximum force required to push a curved surgical needle through a thin laminated synthetic membrane. Three comparable groups of reversed cutting-edge needles were selected from different manufacturers for needle penetration testing. The results of this testing demonstrated that the needle diameter, manufacturing process, and the manufacturer were all important determinants of needle sharpness. Needles with a smaller diameter were sharper than those with a larger diameter. In addition, electrohoned or hand-honed needles were sharper than those subjected to only machine grinding. When comparably sized needles were compared, Ethicon manufactured the sharpest needles, followed by Davis & Geck and Deknatel needles. Scanning electron microscopic photographs and elemental analysis of the surgical needles could be correlated with their sharpness. The sharper needles had long, narrow cutting edge geometries compared with the short wide geometries of duller needles. The sharpest needles were fabricated from an American Society for Testing and Materials (ASTM) 45500 stainless steel alloy that has stronger tensile and yield strengths than those of ASTM 42000 and 42020 alloys used in the creation of the other needles. This stronger alloy allows the manufacturer to produce a longer, narrower cutting point geometry with reduced danger of either bending or breakage during surgery compared with needles made from weaker alloys (ASTM 42000 and ASTM 42020), which accounts for the superior sharpness of the Ethicon surgical needles.

Alloys↗
PubMed1989

A new quantitative measurement for surgical needle ductility.

Because surgical needle ductility is such an important factor in the selection of surgical needles, a new curved needle ductility test instrument was devised to measure the ductility of needles from three commercial manufacturers. The superior ductility of needles made by one manufacturer was related to the specific alloy, stainless steel ASTM 45500, used in their production. The ASTM 45500 stainless steel has a significantly greater tensile and yield strength than the other stainless steel alloys, accounting for its superior ductility.

Humans↗
PubMed1988

Principles of emergency wound management.

Every traumatic wound treated in the emergency department is a result of a finite energy source that caused tissue disruption. The dynamics of this exchange of energy will determine the magnitude of injury. Disruption of the body covering leaves the once-sterile underlying integument exposed to contamination. The contaminants are derived from either the victim (endogenous) or the exogenous energy source. The presence of a contaminant such as bacteria makes the care of the wound an exercise in microbiology. Other contaminants, such as dirt, also may reside in the recesses of the wound. Emergency physicians must understand the consequences of tissue trauma. A study of the mechanism of injury will provide a reliable indication of damages. Whether the tissue injury will be limited to the initial wounding depends on the outcome of the interaction between the contaminants and the wound. In the event that the contaminants are very reactive, a relatively insignificant wound may become a catastrophe. This circumstance can be averted by the implementation of a well-devised plan based on the biology of wound healing and infection.

Anti-Bacterial Agents↗
PubMed1988

Automatic wire twister.

This automatic wire twister used in surgery consists of a 6-inch needle holder attached to a twisting mechanism. The major advantage of this device is that it twists wires significantly more rapidly than the conventional manual techniques. Testing has found that the ultimate force required to disrupt the wires twisted by either the automatic wire twister or manual techniques did not differ significantly and was directly related to the number of twists. The automatic wire twister reduces the time needed for wire twisting without altering the security of the twisted wire.

Bone Wires↗