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Biomedical subjects

D Seligson

Publications and source records attributed to D Seligson.

At least 37 records · Page 2Linked to original sources

Fracture site motion with Ilizarov and "hybrid" external fixation.

OBJECTIVES: To evaluate differences in fracture site motion by using different external fixators. DESIGN: A wooden dowel was used to simulate a long bone with a transverse diaphyseal fracture. Ilizarov, "hybrid," and strutaugmented "hybrid" external fixation was used to stabilize the "fracture." The wooden dowel was subjected to separate axial, four-point bending, and torsional loads. Fracture site motion in the axial plane, off-axis motion (shear and bending), and rotation were measured. SETTING: All mechanical testing was performed with a sevohydraulic test frame (MTS Systems, Minneapolis, MN, U.S.A.). Fracture site motion was measured with an interfragment motion device developed in this laboratory. INTERVENTION: Comparison was made between a traditional fourring Ilizarov fixator, a "hybrid" fixator using rings and threaded pins attached by a unilateral aluminum bar, and a "hybrid" fixator augmented with a V-shaped strut. MAIN OUTCOME MEASUREMENT: Load-deformation behavior in axial displacement, shear displacement, and bending displacement were compared between the different configurations under identical conditions of axial loading, torsional loading, and four-point bending. In torsional loading, rotational displacement was also measured. RESULTS: The Ilizarov configuration allowed significantly less off-axis fracture site motion in all loading modes than either "hybrid" configuration while still allowing axial compression of the fracture ends. CONCLUSIONS: In a completely unstable fracture with poor bone apposition, the mechanical behavior of a four-ring Ilizarov external fixator is superior to the mechanical behavior of a unilateral "hybrid" frame.

Biomechanical Phenomena↗

Vascular compromise and amputation after intramedullary nailing of a tibia fracture.

A case is presented of a fifty-three-year-old man with a displaced tibia-fibula fracture that was treated with an intramedullary nail. The morning after surgery pulses were absent and did not improve after fasciotomies. The patient was transferred to our institution, where an arteriogram showed tapering of the anterior tibial and peroneal vessels in the mid-calf and occlusion of the posterior tibial artery at the level of the ankle. Vascular status did not improve after heparinization and arteriogram thrombolysis. The patient ultimately underwent below-the-knee amputation and subsequent revision to above-the-knee amputation.

Amputation, Surgical↗

Sonography for the office screening of suspected rotator cuff tears: early experience of the orthopedic surgeon.

This study examined the feasibility of orthopedic surgeons performing sonography of the shoulder at the initial office evaluation of the rotator cuff and assessed the sensitivity, specificity, and predictive value of sonography for the detection of tears in the rotator cuff. Initial results in 24 patients suggest that sonography by the orthopedic surgeon is feasible and that it detects tears in the rotator cuff with sufficient accuracy for clinical decision making.

Adult↗

Dynamic external fixation for distal radius fractures.

Thirty adult patients with closed comminuted and mostly intraarticular fractures of the distal radius were treated by closed reduction and immobilization with a dynamic external wrist fixator during a 2-year period. In 13 patients with severely comminuted and unstable fractures, additional Kirschner wires were used. After 10 to 14 days of rigid fixation in neutral position, the motion element was unlocked to allow up to 30 degrees flexion. Six weeks later, the fixator was removed. The patients then were observed for an average of 24 weeks. An excellent functional outcome was seen in 6 patients (20%), a good outcome in 20 patients (67%), and a fair outcome in 4 patients (13%). Anatomically, 15 patients (50%) had an excellent result, 14 (47%) a good outcome, and 1 (3%) a fair outcome. Only minimal loss of reduction averaging 1 degree palmar tilt was seen during mobilization. There were 2 major complications: 1 deep Kirschner wire tract infection and 1 index metacarpal fracture. Minor complications such as sensory disturbances and pin tenderness were present but recovered completely after removal of the fixator. This study provides promising data and offers an alternative method in the treatment of distal radius fractures with severe comminution. In cases with postreductive unstable fragments, additional Kirschner wires should be used to allow early mobilization of the wrist.

Adult↗

Difficulty in removal of certain intramedullary nails.

Intramedullary nailing is the most common treatment for displaced diaphyseal fractures of the femur and tibia. Gerhard Küntscher introduced the technique of intramedullary nailing to clinical practice in the 1940s, and this method has been the focus of many authors with regard to indications, technique, complications, and outcome. The five cases presented here represent a complication not often reported in recent years: the difficulty in removing an intact intramedullary nail. Inspection of the interlocking nails in four of the cases presented reveals a specific design characteristic: the cross sectional design of the nail prevents the distal, unslotted end of the nail from being extracted from the medullary cavity. This problem is preventable by a change in nail design or the development of absorbable implants.

Adolescent↗

In vivo study of stainless steel and Ti-13Nb-13Zr bone plates in a sheep model.

A sheep study was performed to compare the in vivo performance of bone plates of 316L stainless steel and a new titanium alloy, titanium + 13% niobium + 13% zirconium (Ti-13Nb-13Zr), which had been subjected to a diffusion hardening treatment to produce a blue, wear resistant surface. Bone plates and screws of stainless steel and diffusion hardened Ti-13Nb-13Zr were implanted in adult sheep, in one group (with unosteotomized femurs) for 16 weeks, and in the other (with osteotomized femurs) for 8 weeks. At harvest, the diffusion hardened Ti-13Nb-13Zr devices had superior fixation strength, with greater screw torque out strength and fewer loose screws. In the osteotomized animals, the femurs with diffusion hardened Ti-13Nb-13Zr plates had higher torsional strength after removal of the implants; however, the difference was not statistically significant. In the unosteotomized animals, the torsional strength of the femurs was identical for both materials. There was a slightly reduced incidence of infection (bacterial adhesion) for the sheep with diffusion hardened Ti-13Nb-13Zr implants. In a parallel in vitro study, the magnetic resonance imaging compatibility of Ti-13Nb-13Zr was significantly superior to that of stainless steel. This indicates that diffusion hardened Ti-13Nb-13Zr may be an attractive alternative material for osteosynthesis.

Alloys↗

Operative treatment of humeral shaft fractures.

The results of the operative treatment of 27 humeral shaft fractures treated at the University of Louisville during a 2-year period were reviewed. The aim of this study was to analyze 1) the indications and results of surgical treatment, 2) the indications for nailing versus plating, and 3) the failures and their treatment (especially surgical nonunions). Indications for surgery were polytrauma patients (including open fractures, associated neurovascular injuries, associated ipsilateral forearm injuries) and isolated unstable fractures in which closed reduction failed. Plate and screw osteosynthesis was used in patients with proximal and distal fractures, in the presence of neurovascular injuries, progressive radial nerve palsy and failure of closed reduction due to interposition of soft tissue. Intramedullary antegrade nailing was preferentially used in polytrauma patients. Seven patients (25%) needed further surgery because of nonunion. The frequency was higher after plating (30%) than after nailing (20%), it was more common in comminuted fractures, middle third fractures and after insufficient distal locking. Exchange nailing resulted in union in 5 of the 7 cases. Although excellent results with low complication rates are reported in the recent literature following plate and screw osteosynthesis or locked intramedullary nailing, we found that operative treatment of difficult humeral shaft fractures is still fraught with a high complication rate.

Bone Nails↗

Functional outcome of patients with salvageable limbs with grades III-B and III-C open fractures of the tibia.

Numerous reports list predictive criteria to determine whether Gustilio-type tibial III-B and III-C fractures of the tibia are salvageable. What is lacking are long-term reports of comprehensive functional outcome of these severe injuries. We evaluated the functional outcome of patients with our own seven-scale score. Fifty-four patients with 57 types III-B (n = 41) and III-C (n = 16) open tibial fractures sustained between 1980 and 1989 were recalled for evaluation. There were 45 men and 9 women (average age, 28.4 years; range, 4-68 years). Follow-up periods averaged 48.2 months (range, 12-116 months). Salvage rate for the III-B fractures was 75% (n = 31) and for the III-C fractures 37% (n = 6). We conclude that the functional score is a simple and complete method for assessing the functional outcome of patients undergoing limb salvage procedures.

Activities of Daily Living↗

Squamous cell carcinoma of the foot: two case reports.

Plantar keratoses and verrucous lesions are common foot problems in the orthopaedic, dermatologic, and podiatric practices. Treatment often is palliative. Two cases of squamous cell carcinoma are presented to draw attention to the potential for these lesions to deteriorate into malignant lesions. A high index of suspicion is necessary to make the early diagnosis of malignancy and prevent spread of lesions. An initial wide excision may prevent metastasis. Inadequate excision, recurrence, or tumor in the margins should be treated by amputation.

Carcinoma, Squamous Cell↗

Serum bilirubin pigments covalently linked to albumin.

The serum levels of biliprotein (i.e., the bilirubin fraction covalently linked to albumin) were measured in patients with hepatobiliary disease by two analytical procedures: reverse-phase anion-exchange chromatography (Bond-Elut) and anion-exchange chromatography. Bond-Elut extracts contained tetrapyrroles, allowing the analysis of biliprotein, bilirubin, and bilirubin conjugates, whereas the anion-exchange method converted tetrapyrroles to azodipyrroles (protein-free), which were adsorbed on the resin, with the exception of azopyrrole of biliprotein (covalently linked to albumin), which passed through the resin and could be analyzed. In contrast, other cationic polymer columns did not completely bind the alkaline diazo derivatives of unconjugated bilirubin, conjugated bilirubin, or the azopyrrole of biliprotein not bound to albumin. Therefore, a comparison was made of these two methods using the original anion-exchange resin. Both procedures gave similar values for serum levels of biliprotein in patients with high levels of total bilirubin.

Bile Pigments↗

[Treatment concept and results of grade 3 open fractures with arterial injuries requiring reconstruction].

Ninety-one open fractures associated with arterial injury requiring vascular repair (type IIIC injuries) were treated at the University of Louisville between May 1983 and January 1994. Involved anatomical areas were the humerus (6x), the forearm (11x), the femur (16x), the tibia (36x), the ankle (11x) and the foot (11x). Fracture management consisted of meticulous radical debridement, copious wound irrigation, fasciotomy and fracture stabilization. Additionally, 49 wounds (53.8%) were treated with the supplemental local use of antibiotics (tobramycin-PMMA-beads). Thirty-four patients underwent primary amputation whereas 57 repairs of the injured vessels were performed. There were 7 secondary amputations due to infection or poor revascularization resulting in an overall amputation rate of 45.1%. The wound infection rate was 12.1% (11/91) and the rate for osteomyelitis was 3.3% (3/91). The local use of the antibiotic beads was of significant benefit to lower infectious complications. Primary coverage of the soft tissue defect with free tissue transfer was associated with a high infection rate (2/3) and is not recommended for this type of injury. Temporary wound coverage with the "antibiotic bead pouch" technique until wound closure can be obtained in a sterile and viable environment leads to more satisfying results.

Adolescent↗

Is the timing of fracture fixation important for the patient with multiple trauma?

OBJECTIVE: The effect of timing of femur fracture fixation for patients with multiple trauma was studied to determine the effect of operative timing on eventual outcome. METHODS: The relationship between timing of intramedullary rod (IMR) placement, degree of injury, and pulmonary complications was studied in 424 consecutive patients. The authors focused on 105 patients undergoing IMR placement with an Injury Severity score (ISS) of greater than or equal to 18. The effects of timing of IMR placement on various pulmonary complications, organ failure, intensive care unit (ICU) admission, and ventilatory assistance were studied for various time intervals. RESULTS: Of the 424 patients, pulmonary complications increased slightly in the more seriously injured group (ISS > 18) but were not influenced by the timing of IMR placement. Of the 105 patients undergoing IMR placement with an ISS > or = 18, only 2 patients died. Both patients had an IMR placed in less than 24 hours and died later of head injury and delayed hemorrhage. The incidence of organ failure, number of ventilator days, and length of ICU stay did not differ between the groups based on timing of fracture fixation. The incidence of severe head injuries was higher in the group undergoing delayed IMR placement (> 48 hours). CONCLUSIONS: Modest delays in IMR placement did not adversely affect patient outcome. Pulmonary complications were related to the severity of injury rather than to timing of fracture fixation. In a well-integrated trauma system, clinical judgment regarding the timing of IMR placement was the most important determinant of outcome. Delays that were made to stabilize the patient, treat associated injuries, and plan orthopedic reconstruction did not adversely affect patient outcome.

Adult↗

Distal femoral nonunion: treatment with a retrograde inserted locked intramedullary nail.

Between March 1989 and August 1993, 16 distal femoral nonunions (16 patients) were treated using the supracondylar intramedullary nail. The time between the initial event and retrograde nailing averaged 33 months. The nonunion level was infraisthmal in four patients and supracondylar in 12. Operative technique involved retrograde insertion of a reamed supracondylar intramedullary nail through the intercondylar notch. Follow-up was available on all patients and averaged 20 months (range 9-46). Four nonunions (25%) united with a single surgery at an average of 17 months. A fifth nonunion united at 21 months after nail dynamization and subsequent nail breakage. The nonunions of two additional patients united after exchange of a broken retrograde nail. Additional surgical procedures were performed in six of the remaining nine patients in an attempt to gain union. At an average follow-up of 16 months (range 9-23), none of the nine had united. Nine nails fractured at an average of 11 months, all through a screw hole near the nonunion. Based on these results, we cannot recommend use of the supracondylar intramedullary nail in its present form for the treatment of distal femoral nonunions.

Adult↗