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Biomedical subjects

B R Moed

Publications and source records attributed to B R Moed.

At least 19 recordsLinked to original sources
PubMed2001

Accuracy of detecting screw penetration of the acetabulum with intraoperative fluoroscopy and computed tomography.

BACKGROUND: The purpose of this study was to determine the accuracy of computed tomography and fluoroscopy in assessing joint penetration by periacetabular screws. METHODS: A 3.5-mm acetabular periarticular screw was inserted in each of thirty-nine cadaveric hemipelves. Twenty screws were intentionally directed to violate the articular surface, whereas nineteen screws were positioned to avoid the articular surface. Using two fluoroscopic views (tangential and axial) in a manner simulating the clinical setting, an examiner blinded to the actual screw location determined whether each screw was violating the articular surface. In addition, each hemipelvis was examined with computed tomography with use of two different techniques: (1) a 1-mm slice thickness at 1-mm intervals, and (2) a 4-mm slice thickness at 3-mm intervals. Each scan was evaluated by another examiner who was blinded to the actual screw location. Sensitivity, specificity, and percent correct interpretations were then calculated for each method. RESULTS: The sensitivity, specificity, and percent correct interpretations were 95%, 84%, and 90%, respectively, for axial fluoroscopy; 85%, 89%, and 87% for tangential fluoroscopy; 100%, 84%, and 92% for the computed tomography scans with a 1-mm slice thickness at 1-mm intervals; and 100%, 58%, and 79% for the computed tomography scans with a 4-mm slice thickness at 3-mm intervals. Tangential fluoroscopy was found to be more specific than the computed tomography scans with a 4-mm slice thickness at 3-mm intervals (p = 0.02). No other significant differences were found. CONCLUSIONS: Fluoroscopy and computed tomography are equally accurate for determining intra-articular screw penetration. Computed tomography scans with thick slices (4 mm at 3-mm intervals) have a low specificity. Their use postoperatively may lead to a false-positive interpretation of the scan and unnecessary exploration of a hip for screw penetration.

Acetabulum↗
PubMed2000

Fractures of the greater trochanter: intertrochanteric extension shown by MR imaging.

OBJECTIVE: To demonstrate the MR depiction of the intertrochanteric or femoral neck extension of fractures of the greater trochanter, when standard radiographs show only a fracture of the greater trochanter. DESIGN AND PATIENTS: A retrospective review was performed of the MR and radiographic findings in 13 consecutive patients (10 men, 3 women; ages 24-86 years) with radiographic evidence of fracture of the greater trochanter who were examined with MR imaging. RESULTS: The MR study displayed the fracture of the greater trochanter in all cases. In all but three patients, MR examinations displayed an extension of the fracture into the intertrochanteric region, and in one, also an extension into the femoral neck, although the cortex at this level was not interrupted. CONCLUSION: When there is radiographic evidence of an isolated fracture of the greater trochanter, MR often shows an intertrochanteric or femoral neck extension of the fracture in both young and older adults. This finding may be a factor in determining the need for surgical intervention.

Accidental Falls↗
PubMed2000

Open reduction and internal fixation of posterior wall fractures of the acetabulum.

The results of 94 patients with posterior wall fractures of the acetabulum associated with hip instability treated within 3 weeks of injury by open reduction and internal fixation were reviewed. Patients were followed up for an average of 3.5 years (range, 1-13 years). Fracture reductions were graded as anatomic (0-1 mm displacement) in 92 patients and imperfect (2-3 mm displacement) in two patients, as determined by plain radiography. However, postoperative computed tomography scans obtained in 59 patients revealed incongruency of more than 2 mm in six patients and fracture gaps of 2 mm or more in 44 patients. Complications included deep wound infection (one patient), deep vein thrombosis, (seven patients), and revision surgery to redirect an errant screw (one patient). Clinical outcome was graded as excellent in 34 patients (36%), good in 49 (52%), fair in two (2%), and poor in nine (10%). Radiographic results were excellent in 79 hips (84%), good in four (4%), fair in two (2%), and poor in nine (10%). There was a strong association between clinical outcome and radiographic grade. Variables identified as risk factors for an unsatisfactory result included age greater than 55 years, a delay greater than 24 hours from the time of injury for reduction of a hip dislocation, a residual fracture gap greater than 1 cm, and severe intraarticular comminution. The apparent disparity between the accuracy of surgical fracture reduction, as determined by plain radiographs obtained postoperatively, and clinical outcome is explained only partially by the limitations of plain radiography. Other variables are involved, many of which are under the surgeon's control but some are not. As is the case with other acetabular fracture types, the best results are predicated on anatomic fracture reduction.

Acetabulum↗
PubMed2000

Pilon fractures. Treatment protocol based on severity of soft tissue injury.

One hundred seven pilon fractures in 107 patients were treated according to a staged prospective protocol. All pilon fractures were stabilized immediately by the application of calcaneal traction. Open fractures or fractures in patients with multiple injuries were stabilized with traveling traction that was applied in the operating room. A distraction computed tomography scan was obtained before definitive treatment. Treatment groups were based on the degree of soft tissue compromise. Forty-one patients with Tscherne Grade 0 or Grade I injuries underwent open reduction and internal fixation (open plating) using contemporary techniques and low-profile implants. Sixty-four patients with Tscherne Grade II and Grade III closed injuries and all patients with open fractures underwent definitive treatment with limited open reduction and stabilization using small wire circular external fixators. Clinical and radiographic evaluations were performed at an average 4.9 years after injury. For all fracture types (AO classification), 81% of the patients who were treated with external fixation and 75% of the patients who were treated with open plating had good or excellent results. For severe fracture patterns (Type C), patients in both groups had significantly poorer results than patients with Types A and B fractures. The patients in the open plating group had a significantly higher rate of nonunion, malunion, and severe wound complications compared with the patients who received external fixation for Type C fracture patterns. Because of the increased incidence of bony and soft tissue complications when treating open or closed Type C fractures, use of limited exposures and stabilization with small wire circular external fixators is recommended.

Ankle Injuries↗
PubMed1999

Ultrasound of fracture and bone healing.

This article reviews the ultrasound appearance of common fractures that may mimic other pathologies. Recent works suggest a role for ultrasound in the assessment of callus formation in delayed union of fractures and following the Ilizarov reconstructive procedures.

Bone and Bones↗
PubMed1999

Evaluation of intraoperative nerve-monitoring during insertion of an iliosacral implant in an animal model.

BACKGROUND: The use of continuous electromyographic and somatosensory-evoked-potential monitoring systems has been advocated to assist in avoiding nerve-root injury during operations on the pelvic ring. More recently, it was suggested that stimulus-evoked electromyographic monitoring may further decrease the risk of iatrogenic nerve-root injury during posterior pelvic fixation by enabling the surgeon to determine the actual distance of an implant from a nerve root. The purpose of the current study was to evaluate the relative efficacy of these three methods of monitoring for minimizing the risk of neural injury during the placement of iliosacral implants. METHODS: While the function of the first sacral nerve root was monitored with the use of stimulus-evoked electromyographic, continuous electromyographic, and somatosensory-evoked-potential monitoring techniques, a 2.0-millimeter stainless-steel Kirschner wire was progressively inserted, guided by a high-speed computerized tomographic scanner, into the first sacral body of seventeen hemipelves in nine dogs. The end point was contact with the nerve as demonstrated by the computerized tomographic images. It was expected that this end point would be heralded by a burst of spontaneous electromyographic activity and an abnormal somatosensory-evoked-potential signal. Anatomical dissection at the completion of the study documented the final position of the Kirschner wire. RESULTS: Anatomical dissection demonstrated compression or penetration of the nerve root in sixteen of the seventeen specimens. A spontaneous burst of electromyographic activity was not recorded for any specimen on continuous electromyographic monitoring; this finding was significantly different from what had been expected (p<0.001). Because of technical problems, somatosensory evoked potentials could be recorded for only twelve hemipelves that had nerve-root compression or penetration, and abnormal somatosensory evoked potentials were recorded for only one of the twelve; this finding was significantly different from what had been expected (p<0.001). A total of 113 stimulus-evoked electromyographic data points were obtained. The correlation coefficient for the relationship between the current threshold recorded with stimulus-evoked electromyographic monitoring and the distance of the wire from the nerve was 0.801 (p<0.001). The actual measured current thresholds were of an observed proportion not different from what had been expected (p = 0.48). CONCLUSIONS: Continuous electromyographic and somatosensory-evoked-potential monitoring techniques failed to indicate contact with the nerve root reliably in this animal model. However, stimulus-evoked electromyographic monitoring consistently provided reliable information indicating the proximity of the implant to the nerve root.

Animals↗
PubMed1998

[Not Available].

Explore the source record for details and available documents.

Journal Article↗
PubMed1998

Intraoperative stimulus-evoked electromyographic monitoring for placement of iliosacral implants: an animal model.

OBJECTIVE: A canine model was designed to evaluate the feasibility of stimulus-evoked electromyographic (EMG) monitoring of the lumbosacral nerve roots during the insertion of iliosacral implants. STUDY DESIGN/METHODS: Four 2.5-millimeter Kirschner wires (K-wires) were percutaneously inserted under general anesthesia into the S1 body of each of five dog hemipelves using C-arm fluoroscopy image-intensifier control in an actual attempt to compromise the S1 canal and the S1 nerve root. A searching current of twenty milliamperes was initially applied to the K-wire with monitoring electrodes placed in the gastrocnemius muscle. Current thresholds required to evoke an EMG response were recorded for each K-wire. Actual K-wire location was determined by anatomical dissection. RESULTS: Evaluation of these twenty wires revealed that current threshold was directly related to the proximity of the K-wire to the nerve root, with a correlation coefficient of 0.94 (p < 0.001). CONCLUSIONS: Stimulus-evoked EMG monitoring provided reliable data indicating the proximity of the iliosacral implants to the sacral nerve root. This method of intraoperative nerve monitoring could potentially decrease the risk of iatrogenic nerve root injury during pelvic ring surgery. Further study is warranted.

Animals↗
PubMed1998

Outcomes following repair of quadriceps tendon ruptures.

OBJECTIVES: The purpose of this study was to examine critically the outcomes of patients sustaining a quadriceps tendon rupture and to compare outcomes in patients with bilateral simultaneous ruptures versus a unilateral rupture. DESIGN: Retrospective review. SETTING: Patients were treated at a Level I trauma center. PATIENTS/PARTICIPANTS: Fifty-one quadriceps tendon ruptures in thirty-nine patients were evaluated. A mean four-year follow-up (range 13 to 204 months) was available for forty-eight tendon ruptures. INTERVENTIONS: All patients except one were treated with operative repair of the quadriceps tendon rupture(s). MAIN OUTCOME MEASUREMENTS: Patients were assessed by physical examination, Lysholm and Tegner scores, a functional questionnaire, quadriceps isokinetic testing, and radiographs. RESULTS: A statistically greater number of patients in the bilateral simultaneous rupture group had a systemic illness associated with tendon rupture (p = 0.014). This result did not adversely affect outcome as compared with patients with unilateral ruptures. Mean range of motion was 123 degrees in injured knees. Eighty-four percent of working patients returned to their previous occupations. More than half the patients, however, in general the most active, could no longer participate in their preinjury recreational activities. Fifty-three percent of unilateral rupture patients had persistent quadriceps strength deficits (>20 percent) in the injured extremity. Both quadriceps and hamstring isokinetic testing correlated significantly with Lysholm and Tegner scores. CONCLUSIONS: Most patients with bilateral simultaneous and unilateral tendon repairs can expect a good range of motion and return to their previous occupation, but many have persistent weakness and difficulty returning to higher level sporting activities.

Activities of Daily Living↗
PubMed1998

Intraoperative monitoring with stimulus-evoked electromyography during placement of iliosacral screws. An initial clinical study.

A consecutive series of twenty-seven patients who had thirty acute unstable (type-C) fractures of the pelvic ring was studied prospectively to evaluate the use of stimulus-evoked electromyography to decrease the risk of iatrogenic nerve-root injury during the insertion of iliosacral screws. A prerequisite for inclusion in the study was a normal neurological status preoperatively; somatosensory evoked potentials were monitored to further document the neurological status both before and after insertion of the screw or screws. A total of fifty-one iliosacral screws were inserted, and a current threshold of more than eight milliamperes was selected as the level that indicated that the drill-bit was a safe distance from the nerve root. Four of the fifty-one screws were redirected because of information obtained with stimulus-evoked electromyography. Postoperatively, all patients had a normal neurological status. Computerized tomography, although not accurate for detailed measurements, demonstrated that all of the screws were in a safe, intraosseous position. Monitoring with stimulus-evoked electromyography appears to provide reliable data and may decrease the risk of iatrogenic injury to the nerve roots during operations on the pelvic ring.

Adolescent↗
PubMed1998

Comparison of the compression hip screw with the Medoff sliding plate for intertrochanteric fractures.

The Medoff sliding plate was designed to achieve compression along the femoral neck and the longitudinal axis of the femoral shaft theoretically to improve the treatment of intertrochanteric hip fractures. The Medoff sliding plate was compared with a standard compression hip screw in a randomized, prospective study for the fixation of 160 stable and unstable intertrochanteric fractures with an average followup of 9.5 months (range, 6-26 months). Overall, 91 fractures were treated using the compression hip screw and 69 were treated with the Medoff sliding plate. Stable fracture patterns (46) united without complication in both treatment groups. Unstable fractures (114) had an overall failure rate of 9.6%, 14% (nine patients) with the compression hip screw and 3% (two patients) with the Medoff plate; this difference was significantly different. The time to union for the 114 unstable fractures was not significantly different between the two devices. For all patients, no differences in lengths of hospitalization, return to ambulatory status before fracture, postoperative living status, or postoperative pain was observed between the two device groups. Use of the Medoff plate for all fracture types was associated with a significantly higher amount of blood loss and operating time.

Activities of Daily Living↗
PubMed1998

Reharvest of iliac crest donor site cancellous bone.

Patients requiring cancellous bone grafting of an extensive deficit or multiple bone grafting procedures often lack a sufficient quantity of autogenous cancellous bone. Canine studies have indicated that a potential exists for reharvesting autogenous cancellous bone from an iliac crest donor site using a trapdoor harvesting technique. However, significant human experience with this procedure has been lacking. This report describes four patients who underwent successful reharvesting of an iliac crest donor site that provided clinically sufficient autogenous cancellous bone graft material to treat an ongoing or a new skeletal problem. These patients all met specific criteria regarding use of the trapdoor method of bone graft harvest and a minimum 24-month interval between bone grafting procedures. Preoperative computed tomography scanning of the iliac crest was useful in documenting that sufficient cancellous bone was available for reharvest. It appears that iliac crest donor site reharvesting is a specific advantage of the trapdoor technique and is a possible alternative to multiple site grafting or the use of allograft or bone substitute materials.

Adolescent↗
PubMed1998

Heterotopic bone formation in male and female rabbits.

We performed mechanical induction of heterotopic ossification in the quadriceps of the right hind limb of six male and six female sexually mature New Zealand white rabbits of similar size. The effect of sex difference on heterotopic bone was assessed by analyzing plain radiographs of the femur. The results indicate that a male/female sex difference in heterotopic bone formation cannot be demonstrated.

Animals↗
PubMed1997

Early complications in the operative treatment of patella fractures.

OBJECTIVE: To identify and review early complications in the operative treatment of patella fractures. DESIGN: Retrospective review. SETTING: Single tertiary care institution with multiple surgeons, including generalists and fellowship trained subspecialists. PATIENTS: A consecutive series of eighty-seven patella fractures over a five year period was reviewed. Patients treated nonoperatively or with partial or total patellectomy were excluded. Minimum follow-up to fracture healing (four months) was available in fifty-one fractures. INTERVENTION: Modified tension band wire fixation was used in forty-nine fractures, whereas two fractures were treated with tension band wires threaded through cannulated screws. OUTCOME MEASURES: Early complications such as loss of reduction or fixation, infection, or soft-tissue problems were evaluated. RESULTS: Displacement of > or = 2 mm before healing was noted in eleven fractures. The displacement could be attributed to technical errors in five cases, and to patient noncompliance with postoperative activity restrictions in another five cases. Two cases of superficial infection were documented. Nine patients with symptomatic hardware required hardware removal. CONCLUSIONS: Twenty-two percent of fractures treated with tension band wiring and early motion displaced > or = 2 mm within the early postoperative period. Technical errors or patient noncompliance were identified as factors. The incidence of early complications in operatively treated patella fractures is higher than previously reported.

Adolescent↗
PubMed1997

Intramedullary nailing of unstable diaphyseal fractures of the tibia with distal intraarticular involvement.

OBJECTIVE: To evaluate the efficacy of intramedullary nailing in diaphyseal tibia fractures with distal intraarticular involvement. DESIGN: Retrospective. SETTING: Henry Ford Hospital, a level I trauma center. PATIENTS/PARTICIPANTS: Twenty patients with twenty fractures at an average of twenty-two months of follow-up were evaluated. There were fifteen closed and five open fractures. INTERVENTION: All fractures were stabilized with lag screw fixation (with or without supplemental plates) of the intraarticular-fracture extension or ankle fracture, and intramedullary nailing of the diaphyseal tibia fracture. MAIN OUTCOME MEASUREMENTS: Time to bony union, malunion, knee and ankle range of motion, early arthrosis, and any complications of treatment were assessed. RESULTS: Nineteen fractures healed, with an average time to bony union of seventeen weeks. One nonunion after a grade IIIB open fracture required exchange nailing and healed after sixty-two weeks. Nineteen fractures had excellent alignment after healing. There were no infections. CONCLUSIONS: The indications for intramedullary nailing of unstable diaphyseal tibia fractures may be extended to include certain fractures with distal extension into the ankle joint, as well in a tibial shaft fracture occurring in combination with a noncontiguous ipsilateral ankle fracture.

Adult↗
PubMed1996

Techniques for reduction and fixation of pelvic ring disruptions through the posterior approach.

Open reduction and internal fixation through the posterior approach has an important role in the management of unstable Type C pelvic ring injuries. Using the described techniques, the goals of anatomic reduction and stable fixation can be attained. However, the potential exists for significant complications. Careful patient selection and attentiveness to detail minimize these risks.

Bone Screws↗