Biomedical subjects

G S Gurwitz

Publications and source records attributed to G S Gurwitz.

3 recordsLinked to original sources

PubMed1994

Intraoperative cardiopulmonary resuscitation in the prone position.

Cardiopulmonary resuscitation (CPR) occasionally is necessary in the operating-room setting. In such instances, it may be difficult to perform CPR if the patient is in the prone position. Although the supine position is optimal for CPR, it may not be feasible because of the risks of damage to craniospinal structures. The authors present the case of a 12-year-old boy who had cardiac arrest during spinal fusion. Successful CPR was performed with the patient in the prone position, with the use of "reversed precordial compressions," and the patient was resuscitated despite 7 minutes of asystole. Effective cardiac output was maintained and was confirmed by systolic blood pressure readings of 80 to 90 mm Hg on both the arterial catheter waveform and the noninvasive blood pressure cuff, by a waveform and the reading on the pulse oximeter, and by the presence of end-tidal carbon dioxide.

Cardiopulmonary Resuscitation↗

PubMed1993

Biomechanical analysis of three surgical approaches for lumbar burst fractures using short-segment instrumentation.

Burst fractures of the lumbar spine that are located below the thoracolumbar junction present a challenge when operative management is indicated. Short-segment instrumentation offers the advantage of incorporating fewer motion segments in the fusion, but may not provide adequate long-term stabilization. The goal of this study was to assess the axial stiffness and torsional rigidity of several short-segment instrumentation procedures. Compressive axial stiffness and torsional rigidity were measured in six intact porcine lumbar spines (L1-L5). A corpectomy was performed to simulate a burst fracture injury and decompression. Posterior instrumentation, posterior instrumentation with an anterior strut (a wood block), and anterior instrumentation with an anterior strut one level above and one level below the fracture site were applied as treatment strategies. VSP plates (Acromed, Cleveland, OH) for posterior instrumentation and the Kaneda system (Acromed, Cleveland, OH) for anterior instrumentation were used. Load-displacement and torque-angle plots were generated and used to calculate 144 estimates of axial stiffness and 144 estimates of torsional rigidity for these constructs. These analyses showed that, in comparison with the intact spine, posterior instrumentation alone was an average of 76% less stiff axially, posterior instrumentation with an anterior strut was 3% more stiff (not significantly different from intact), and anterior instrumentation with an anterior strut was 15% more stiff. Posterior instrumentation alone was an average of 30% less rigid in torsion, posterior instrumentation with an anterior strut was 26% less rigid, and anterior instrumentation with an anterior strut was 24% less rigid than the intact spine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Inflammatory synovial fluid and absorbable suture strength.

The effect of inflammatory synovial fluid upon several absorbable sutures commonly used for meniscus repair was studied by implanting lengths of these sutures into unstable, arthritic rabbit knees and, after varying lengths of time (1-6 weeks), testing their breaking strength. Both polyglactin-910 (Vicryl) and polyglycolic-acid (Dexon) sutures retained only minimal breaking strength 3 weeks after implantation. Chromic gut sutures demonstrated a steady reduction in breaking strength until they retained only 6% of their original strength at 5 weeks and none at 6 weeks. Polydioxanone (PDS) sutures began to lose breaking strength at 2 weeks and retained only 40% of their original strength 5 weeks after implantation. The rate of loss in polydioxanone breaking strength was faster in inflammatory synovial fluid than previously reported in the normal synovial joint. Braided polyester sutures (Mersiline) showed no loss of breaking strength over the duration of this test. While the choice of suture is only one variable influencing the outcome of a meniscus repair, this study demonstrates that only polydioxanone and green braided polyester sutures retain any strength 6 weeks after implantation (the time of immobilization commonly recommended for meniscal repairs). Complete meniscal healing can require several months. In the absence of compelling evidence to the contrary, the use of nonabsorbable suture materials for meniscal repair seems the most appropriate choice.

Absorption↗