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Biomedical subjects

D Seligson

Publications and source records attributed to D Seligson.

At least 91 records · Page 5Linked to original sources

Coefficient of static friction at pig femoral osteotomies: the role of anatomic reduction and compression on the value of the coefficient.

The coefficient of static friction for pig femora following an osteotomy has been determined in vitro. It was found that the coefficient had a value of 0.46 +/- 0.05, and that this was independent of the reduction force applied to the osteotomy site, provided there was good anatomical reduction. When the osteotomy was not anatomically reduced, the coefficient of friction varied in a linear manner with the applied reduction force.

Animals↗

Antibiotic-metal interactions in saline medium.

The commonly used surgical alloys, stainless steel, titanium and Vitallium, were exposed to normal saline solution containing antibiotics frequently used for the control and treatment of orthopaedic infections and the corrosion potential versus time behaviour was followed. It was found that only one antibiotic, oxytetracycline, exerted a significant effect on electrochemical behaviour, producing an anodic shift of 120-250 mV in the Ecorr of the three metals. The study indicated that oxytetracycline at addition levels of 0.01-1.0 mg/ml acts as an anodic corrosion inhibitor.

Chromium Alloys↗

The in vivo behavior of gentamicin-PMMA beads in the maxillofacial region.

Gentamicin-PMMA beads were placed in maxillofacial wounds of ten dogs, and gentamicin levels from wound drain sites, serum, and urine were measured by radioimmunoassay. The results indicate extremely high wound and modest urine levels (which decrease exponentially) concurrently with negligible serum levels of gentamicin. The results of this study of a highly vascularized area were similar to other studies in which beads were placed in avascular areas.

Animals↗

Psychiatric assessment of leg fracture patients: a pilot study.

Of 200 consecutively admitted leg fracture patients, 101 consented to be screened for psychopathology using the BSI and SMAST questionnaires. Probable cases of psychopathology were referred for diagnostic psychiatric evaluation. Of the participants, 80.2 percent were identified as possible psychiatric cases. Diagnostic evaluation revealed high prevalence of substance abuse (66.0%), depression (46.8%), and personality pathology (38.3%). Accident victims tended to be single young males. Accidents occurred mostly during leisure hours, and were often associated with alcohol use. Psychiatric assistance appears essential in the management of such patients. Psychiatrists need to be especially knowledgeable about chemical dependency, interpersonal issues and psychotherapy.

Accidents↗

Ankle arthroscopy: a method of distraction.

Although ankle arthroscopy has been limited by the restricted available joint space, the use of distraction in addition to joint distention has permitted improved surgical and diagnostic examination of the ankle. In contrast to previously described methods of distraction, a simple, effective, and noninvasive method of distracting the ankle joint is proposed. This method requires no special equipment: a standard fracture table, adhesive tape, and sterile self-adherent bandages are used to provide successful joint distraction as demonstrated radiographically.

Adult↗

[Treatment of 2d and 3d degree complicated tibial shaft fractures with the PMMA bead pouch technic].

In a consecutive series of 222 compound fractures treated at the University of Louisville Level I Trauma Center from November 1984 to January 1987, 21 severe compound tibia shaft fractures in 20 patients were managed with the antibiotic bead pouch technique. There were 5 tibia shaft fractures and 16 tib-fib fractures. There were 9 type II and 12 type III (4 III A and 8 III B) open tibias. The patients' ages ranged from 16 to 50 years; the mean age was 29 years. There were 19 men and 1 woman. The Injury Severity Score (I.S.S.) ranged from 9 to 34; the mean I.S.S. was 14.4. Porous plastic film (Opsite) is placed over the soft tissue defect to establish a "closed" bead - hematoma - fracture environment containing high local levels of antibiotic at the fracture site. All patients had external skeletal fixation, serial wound débridement, and parenteral systemic antibiotics (cefazolin, penicillin, tobramycin). An aggregate of 46 bead pouch changes were performed in the 21 tibia fractures. During these changes, 86 cultures were taken, 5 of which were positive. One patient developed a wound infection, which was caused by tobramycin-resistant Pseudomonas and Enterococcus. No cases of osteomyelitis were observed at the fracture site. Wound closure was obtained in 9 fractures with delayed primary closure, and in 12 fractures with flap coverage and/or split thickness skin grafting. All patients underwent autogenous cancellous bone grafting after wound closure was established. The mean follow-up was 26 months (range 13-43 months). At final follow-up, 4 results were rated excellent, 11 good, 3 fair and 3 poor.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

The tip of the iceberg: psychiatric consultations on an orthopedic service.

One hundred and one consecutively admitted orthopedic patients with leg fractures participated in a study assessing psychiatric morbidity using the BSI- and SMAST-questionnaires. Patients identified as probable cases of psychopathology were then psychiatrically evaluated to establish diagnoses. It was determined that about 70 percent of the sample met the criteria for psychiatric diagnoses, with substance abuse being the leading group of disorders. The psychiatric consultation-liaison and orthopedic services remained blind to the research activities and continued to refer patients for psychiatric consultation when clinically necessary. Only six (5.9%) of the patients also participating in the study were referred for clinical consultation, and these appeared to have very obvious symptoms or complaints. The large majority of emotional distress remained unnoticed.

Fractures, Bone↗

Wound and serum levels of tobramycin with the prophylactic use of tobramycin-impregnated polymethylmethacrylate beads in compound fractures.

Antibiotic-impregnated polymethylmethacrylate (PMMA) beads have been useful in treating orthopedic infections. Local delivery has been reported to establish wound antibiotic levels well above the therapeutic range while avoiding serum levels associated with increased incidence of side effects. After operative debridement, 70 patients with compound fractures were treated prophylactically with tobramycin-impregnated PMMA beads. Observations of antibiotic levels in 27 patients demonstrated antibiotic levels in the wound drainage and clot that were significantly in excess of the usual therapeutic range for tobramycin and simultaneous nontoxic serum levels. Significant levels of tobramycin can be achieved in the extracellular fluid at the fracture site when tobramycin-impregnated PMMA beads are placed in the wound after irrigation and debridement.

Debridement↗

Intramedullary fixation of subtrochanteric fractures with the Williams Y-nail: report of three cases.

Küntscher Y-nailing is indicated for unstable proximal fractures of the femur in the elderly (5-7,10). The Williams modified Y-nail is an interlocking Y-nail that was designed to extend the indications beyond those of the Küntscher Y-nail. The Williams Y-nail was employed in three cases of subtrochanteric and subtrochanteric-intertrochanteric fractures, including one case in which there was an ipsilateral femoral shaft fracture. This procedure requires reaming and interlocking which are not performed in classic Küntscher Y-nailing. At follow-up (14-month minimum), each patient had a good clinical result and radiographic healing. Leg length shortening (maximum, 1.5 cm) occurred in two of three cases, primarily as a result of the failure to employ either a proximal or a distal interlocking screw. No other deformities have been observed. Williams Y-nailing can extend the indications of the Küntscher Y-nail to include rotationally unstable subtrochanteric fractures and associated ipsilateral femoral shaft fractures. The increased technical demands of the Williams modified Y-nail warrant cautious use depending upon the complexity of the fracture. Used properly, the Williams Y-nail may reduce the incidence of rotational and leg length deformities often experienced with other commonly used devices for unstable subtrochanteric and ipsilateral trochanteric-diaphyseal fractures of the femur.

Aged↗

Cracking of a coated orthopaedic external fixation connecting bar.

During the course of a routine orthopaedic surgical procedure, a stainless steel external fixation connecting bar was deliberately bent to accommodate the patient's anatomy. It was found that the bar carried a nickel electrodeposited coating that flaked off the bar surface due to the bending. It is believed that the presence of a nickel coating might cause adverse tissue responses in patients and surgeons should be aware that connecting bars for external fixators might carry such coatings.

Drug Hypersensitivity↗

Heat of intramedullary reaming.

Cortical ischemia and necrosis after intramedullary reaming are well documented. Numerous authors have described ischemic changes attributed to mechanical disruption of the arterial system of the intramedullary canal. Few have investigated the potential thermal injury during extreme temperatures generated during intramedullary reaming. We reamed the medullary canal of cadaveric tibial and femoral diaphyses using a flexible shaft reaming device and stainless steel intramedullary reamer. The temperatures generated by reaming from 11 mm through 15 mm in 1 mm increments were measured after each pass. In the 17 specimens tested, we observed an incremental rise in temperature with reaming. The mean intramedullary temperature after reaming was 52 C ( +/- 8.3) with a range of 42 to 67 C. The mean extramedullary temperature was 46 C ( +/- 8.3) with a range of 36 to 59 C. There was a direct correlation between temperature increase and reamer size. Our results indicate that temperature elevations generated during intramedullary reaming are sufficient to cause thermal necrosis, and may cause delayed healing in vivo.

Aged↗

Analysis of the effect of using two different strain rates on the acoustic emission in bone.

To study the effect of strain rate on the acoustic emission amplitude signature of bone, bovine cortical bone was milled into standard tensile specimens which were tested at two different strain rates while being monitored with acoustic emission equipment. It was demonstrated that the amplitude distribution of the acoustic events in bone is dependent on strain rate. Greater numbers of events occurred with the slower strain rate (0.0001 s-1), but these events were of lower amplitude than those emitted during the more rapid strain rate (0.01 s-1). The plot of the cumulative event amplitude distribution followed the power-law model, and the slope of this output, the b-value, represented a signature of the amplitude distribution. The mechanical test results were consistent with the behavior of a viscoelastic multi-phase composite material.

Acoustics↗

Leaching of tobramycin from PMMA bone cement beads.

The in vitro leaching characteristics of tobramycin from acrylic resin (PMMA) bone cement beads have been determined by a radioimmune assay. Tobramycin was incorporated at two concentrations into bone cement beads fabricated from three commercial brands of acrylic resin. Antibiotic leaching followed a curvilinear relationship of the form X . Y = A . X + B . Y. All beads showed similar tobramycin leaching rates over time but the initial amount of leached material differed with the amount of tobramycin incorporated in the bead and the source of the PMMA bone cement. The data indicate that tobramycin-impregnated PMMA beads permit antibiotic leaching at a controlled rate compatible with possible clinical application.

Bone Cements↗

Importunate fractures.

The treatment of compound fractures has been discussed extensively in the literature. Little has been written, however, about the closed fracture that compounds in the hospital environment. This paper discusses three cases of importunate fracture, with skin breakdown and exposed fracture fragments, and their treatment with tobramycin beads (and in two cases, external fixateurs).

Adult↗