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Biomedical subjects

W McGregor

Publications and source records attributed to W McGregor.

At least 19 recordsLinked to original sources
PubMed1997

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.

Animals↗
PubMed1997

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.

Animals↗
PubMed1997

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.

Animals↗
PubMed1996

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.

Biomechanical Phenomena↗
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↗
PubMed1992

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↗
PubMed1991

Laser-drilled cardiovascular surgical needles.

Surgical sutures that are directly attached to the surgical needle ends are called swaged sutures. A forming tool has been used to split one-half of the wire diameter of cardiovascular needles that forms a channel or receptacle for the suture. With the advent of lasers, uniform holes can now be produced in the ends of small-diameter cardiovascular needles. An advantage of the laser-produced hole is that its outer circumference is smooth; the channel swage has a linear slit that interrupts its smooth outer circumference. A standardized reproducible test has been developed that quantitates the force required to pull the needle end through a synthetic membrane that simulates vascular tissue. A swage produced by a laser encountered significantly less drag forces than that noted with a comparable size channel swage of cardiovascular needles.

Cardiac Surgical Procedures↗
PubMed1991

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↗
PubMed1990

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.

Equipment Design↗
PubMed1989

New atraumatic rounded-edge surgical needle holder jaws.

A new atraumatic smooth needle holder jaw with rounded edges that does not damage synthetic monofilament sutures is described herein. These rounded edges were created by mechanical filing of the sharp edges of smooth needle jaws. Compression of the monofilament suture between the needle holder jaw with sharp edges reduces the suture breaking strength compared with that of control sutures. A quality control method has been devised to detect the potentially damaging sharp edges of smooth needle jaws that can be easily implemented by needle holder manufacturers.

Suture Techniques↗
PubMed1989

Needle holder damage to surgical needles.

Clamping surgical needles between the jaws of needle holders with teeth markedly weaken the needles, making them prone to breakage. In contrast, clamping surgical needles between either smooth needle holder jaws or jaws embedded with tungsten carbide particles did not alter the ductility of surgical needles.

Alloys↗
PubMed1988

Surgical needle holder damage to sutures.

Needle holder jaws with teeth produce distinct structural changes in synthetic sutures that cause a marked reduction in the suture breaking strength. This damage to the suture may account for disruptions of vascular and fascial wound closures in which continuous closure techniques are employed.

Humans↗
PubMed1988

Observations on the development of tick-transmitted Theileria buffeli (syn T orientalis?) in cattle.

The development and morphology of Australian Theileria buffeli in cattle were studied after infection had been experimentally transmitted by the tick, Haemophysalis humerosa. Macroschizonts of T buffeli were demonstrated in Giemsa's stained lymph node preparations for between six and 20 days following tick infestation. The presence of schizonts was confirmed by immunofluorescence with sera from known infected animals. Microschizonts were seen infrequently. The schizonts and piroplasms of T buffeli are morphologically similar to those of T orientalis.

Animals↗