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Biomedical subjects

J G Birch

Publications and source records attributed to J G Birch.

At least 19 recordsLinked to original sources
PubMed2000

Developmental coxa vara associated with spondylometaphyseal dysplasia (DCV/SMD): "SMD-corner fracture type" (DCV/SMD-CF) demonstrated in most reported cases.

BACKGROUND: This paper reports three children with short stature: developmental coxa vara unilateral in the first case and bilateral in the other two; somewhat squared and "ovoid" vertebral bodies in the first patient, and normal to slightly tall vertebral bodies in the third; metaphyseal changes in some long tubular bones including bone fragments similar to the corner fractures seen in child abuse in all three patients. MATERIALS AND METHODS: The first and second patients were sisters; their mother, also quite short, had surgical procedures in early life for bilateral "coxa vara"; their brother, also of short stature, had bilateral coxa valga with otherwise normal femoral heads and necks, and mild metaphyseal changes associated with two minute "corner fractures" in the proximal metaphysis of the left tibia. RESULTS: A review of reported cases of developmental coxa vara associated with spondylometaphyseal dysplasia revealed that simulated corner fractures were present in most instances.

Bone and Bones↗
PubMed1999

Syme amputation for the treatment of fibular deficiency. An evaluation of long-term physical and psychological functional status.

BACKGROUND: Syme amputation is an accepted treatment for fibular deficiency. With improvement in limb-lengthening procedures, there has been renewed interest in limb salvage for these patients. The purpose of the present study was to evaluate the physical and psychological results in ten young adults who had had a Syme amputation for the treatment of fibular deficiency when they were children. METHODS: The evaluation consisted of physical examination, prosthetic assessment, psychological testing, and physical performance testing of knee extension and flexion with use of a Cybex-II dynamometer. RESULTS: Five patients reported no difficulty with the involved limb since the Syme amputation, four had had minor secondary procedures (three medial distal femoral or proximal tibial hemiepiphyseodeses, one reconstruction with an autologous patellar ligament graft, one revision of the stump, and one tibial osteotomy) on the affected extremity, and one had mild instability of the knee that had been treated nonoperatively. All ten patients had an appropriate, functional Syme prosthesis, and none reported difficulty with walking or running. On psychological testing, this group generally did not differ from the norm with regard to occupational satisfaction, personal growth, relationships with family members and peers, and recreational behavior. The patients' overall assessment of self-reported quality of life and self-esteem was similar to that of normative adult samples. In general, these patients were leading active, productive lives and had always done so. CONCLUSIONS: On the basis of the results of this study, we concluded that young adults who have had a Syme amputation apparently are not limited in their ability to pursue and achieve personal goals. In order to justify recommending limb salvage rather than early Syme amputation for the treatment of fibular deficiency, the results of multistaged lengthening and reconstruction would have to match the functional, psychological, and cost-effective results for the patients whom we studied, who had had a Syme amputation.

Adolescent↗
PubMed1998

Orthopedic management of neuromuscular disorders in children.

In many cases, the orthopedic surgeon may be the first consultant requested to assess complaints of lower extremity weakness or deformity to result from such conditions and must remain alert to the primary diagnosis. In addition, the orthopedic surgeon should be prepared to guide appropriate physical therapy, prescribe orthotics, and perform surgery to improve function, prevent deformity, or provide comfort when necessary. Most deformities of the extremities result from a combination of muscle weakness and imbalance, and surgical procedures are aimed at correcting existing deformity and rebalancing existing musculature by release or transfer. Skeletally immature patients with neuromuscular disorders are also susceptible to the development of scoliosis, which may impair comfortable sitting or already compromised pulmonary function. This article reviews the clinical manifestation and orthopedic management of Duchenne's muscular dystrophy, spinal muscular atrophy, facioscapulohumeral dystrophy, and Charcot-Marie-Tooth disease.

Adolescent↗
PubMed1998

Histomorphometry of distraction osteogenesis in a caprine tibial lengthening model.

Standardized histomorphometry of bone formation and remodeling during distraction osteogenesis (DO) has not been well characterized. Increasing the rhythm or number of incremental lengthenings performed per day is reported to enhance bone formation during limb lengthening. In 17 skeletally immature goats, unilateral tibial lengthenings to 20 or 30% of original length were performed at a rate of 0.75 mm/day and rhythms of 1, 4, or 720 times per day using standard Ilizarov external fixation and an autodistractor system. Two additional animals underwent frame application and osteotomy without lengthening and served as osteotomy healing controls. Histomorphometric indices were measured at predetermined regions from undecalcified tibial specimens. Within the distraction region, bone formation and remodeling activity were location dependent. Intramembranous bone formed linearly oriented columns of interconnecting trabecular plates of woven and lamellar type bone. Total new bone volume and bone formation indices were significantly increased within the distraction and osteotomy callus regions (Tb.BV/TV, 226% [p < 0.05]; BFR/BS, 235-650% [p < 0.01]) respectively, compared with control metaphyseal bone. Bone formation indices were greatest adjacent to the mineralization zones at the center of the distraction gap; mineral apposition rate 96% (p < 0.01); mineralized bone surfaces 277% [p < 0.001]); osteoblast surfaces 359% [p < 0.001]); and bone formation rate (650% [p < 0.01]). There was no significant difference (p < 0.14; R = 0.4) in the bone formation rate of the distracted callus compared with the osteotomy control callus. Within the original cortices of the lengthened tibiae, bone remodeling indices were significantly increased compared with osteotomy controls; activation frequency (200% [p < 0.05]); osteoclast surfaces (295% [p < 0.01]); erosion period (75%); porosity (240% [p < 0.001]). Neither the rhythm of distraction nor the percent lengthening appeared to significantly influence any morphometric parameter evaluated. Distraction osteogenesis shares many features of normal fracture gap healing. The enhanced bone formation and remodeling appeared to result more from increased recruitment and activation of bone forming and resorbing cells rather than from an increased level of individual cellular activity.

Animals↗
PubMed1996

Effects of external fixation and limb lengthening on peripheral nerve function.

To identify factors affecting peripheral nerve function during limb lengthening, serial somatosensory evoked potentials studies were performed in 18 goats and correlated with gross appearance of the soft tissues at necropsy. In 15 goats, a 20% or 30% tibial lengthening was done using the Ilizarov apparatus at a rate of 0.75 mm per day and rhythm of 1, 4, or 720 times per day. Three animals served as frame/corticotomy controls. Seven lengthened and 2 control animals maintained normal somatosensory evoked potentials throughout the study. At necropsy, the peroneal and tibial nerves appeared grossly normal. In one control animal with irreversible loss of evoked potentials documented intraoperatively, peroneal nerve impalement by a transfixion wire was identified at necropsy. Eight lengthened animals experienced significant changes of peroneal nerve conduction. In 6 of these 8 animals, transfixion wires were found to be disrupting the nerve in some way. In the remaining 2 animals, no offending wires were identified, but there was extensive diffuse soft tissue fibrosis within the extremity. The rhythm of distraction did not have an important influence on evoked potential changes during the course of distraction. Although there was a correlation between the amount of lengthening performed and the degree of evoked potentials deterioration, the anatomic relationship between the wires and nerves was a more important factor in the development of these abnormalities.

Animals↗
PubMed1996

Cervical kyphosis in patients who have Larsen syndrome.

Four patients who had Larsen syndrome and cervical kyphosis were managed operatively and followed for an average of seventy months (range, forty to ninety-two months). The preoperative cervical kyphosis ranged from 35 to 65 degrees. The patients had had a posterior cervical arthrodesis alone when they were infants, at an average age fo fourteen months (range, ten to sixteen months). In three infants, the kyphosis either stabilized (one patient) or reversed into lordosis (two patients). Thus, the kyphosis corrected gradually by continued anterior growth in the presence of a solid posterior fusion. In the fourth infant, the kyphosis progressed to 110 degrees because of pseudarthrosis. This child had anterior decompression and arthrodesis for an acute neurological deficit. We believe that cervical kyphosis is sometimes present but not diagnosed in patients who have Larsen syndrome. Early diagnosis followed by operative stabilization should help such patients avoid neurological deficits. Posterior cervical arthrodesis alone, performed in infancy, provided stability and the opportunity for the gradual correction of the deformity by continued anterior growth in three of our four patients.

Abnormalities, Multiple↗
PubMed1995

Computer-assisted surgery planning for lower extremity deformity correction by the Ilizarov method.

Starting in 1952, Prof. Gavril Ilizarov, a Russian orthopedic surgeon, devised a complex method of long bone deformity correction using an external bone fixation system consisting of rings and wires. We have developed a computer-assisted surgery planning system to aid in correction using the Ilizarov method. The hardware for the system is composed of an ultrasonic digitizer as input device, an HI plotter as output device, a 386/486 personal computer with super VGA monitor, and a mouse interfacing between user and computer. The software includes two separate programs. The main program is a menu-driven two-dimensional graphics program, which divides the planning procedure into several major stages, including preoperative planning and postoperative verification. The second program uses the information generated from the first program to create an image of the ideal three-dimensional frame construction to give a general impression of the appearance of the constructed frame.

Computer Simulation↗
PubMed1994

Treatment of adolescent idiopathic scoliosis using Texas Scottish Rite Hospital instrumentation.

STUDY DESIGN: To determine the effectiveness of posterior TSRH instrumentation for the treatment of idiopathic scoliosis, 103 patients with a 2-year minimum followup were retrospectively studied. METHODS: Patients who underwent operations between October 1988 and April 1991 were evaluated for curve correction, spinal balance, and complications. Age at surgery averaged 14.3 years. Follow-up averaged 2.5 years. RESULTS: Thoracic curve correction averaged 65% in those with King Type III/IV curves and 54% in those with Type II curves. With follow-up, correction loss averaged approximately 13% for each group. Lumbar curve correction after instrumentation in Type I and II curves averaged 48% postop but lost approximately 20% with follow-up. Trunk balance improved 77% toward midline after surgery in those with Type III/IV curves. Improvement in trunk balance was less impressive in patients with Type II curves, particularly after selective thoracic fusions. Thoracic sagittal contour improved 43% for hypokyphotic (< 20 degrees) patients but, in the remainder, no significant radiographic change was evident. No neurologic complications occurred. Delayed deep infections developed in ten patients (10%) between 11 and 45 months postoperative. Cultures eventually grew Propionibacterium acnes, staph epidermidis, or staph coagulase negative in eight patients. Two patients had pseudarthroses. CONCLUSIONS: Frontal and sagittal thoracic curve correction can be satisfactorily obtained using TSRH instrumentation. Continued efforts are being made to improve lumbar hook patterns and technique to achieve and maintain better lumbar curve correction.

Adolescent↗
PubMed1994

Somatosensory evoked potential evaluation of acute nerve injury associated with external fixation procedures.

The effects of different mechanisms of acute nerve injury on peripheral nerve function during K wire application and 1 stage limb lengthening were evaluated prospectively in 24 goats using somatosensory evoked potentials. Stable somatosensory evoked potential recordings throughout 3-day experiments were obtained in animals with wires placed at a distance from or directly adjacent to a nerve but without producing any tension or pressure. Complete loss of the peroneal nerve somatosensory evoked potentials occurred if this nerve was perforated by wire, underwent excessive pressure by wire, or had been over-stretched due to acute 10% limb lengthening. Acute distraction resulted only in peroneal nerve dysfunction, while the tibial nerve was relatively unaffected. Although somatosensory evoked potential changes were not specific for the type of injury produced and the time of waveform disappearance varied, significant somatosensory evoked potential changes (> 50% amplitude reduction, > 10% latency delay or both) were seen within the first 15 minutes after injury in 90% of the cases. The somatosensory evoked potential changes did not reverse if the offending wire or distraction was left in place for the full duration of the experiment. Variable nerve conduction recovery was observed in all animals who had the insult removed immediately after the somatosensory evoked potentials disappearance. The greatest improvement occurred after discontinuation of nerve distraction. The worst somatosensory evoked potential waveform recovery was noted in animals with nerve perforation. Intraoperative somatosensory evoked potential monitoring proved to be a reliable and useful technique for earlier detection of acute nerve injury during external fixation procedures.

Animals↗
PubMed1992

Pelvic support femoral reconstruction using the method of Ilizarov: a case report.

A 15-year-old boy presented with a fixed, irreducible congenital dislocation of the hip associated with other multiple lower extremity growth disturbances secondary to neonatal multifocal osteomyelitis. The affected hip had very limited abduction, and the patient had a very severe Trendelenburg gait secondary to the dislocation. The hip was reconstructed according to the Ilizarov method, by a combination of maximum proximal femoral adduction osteotomy in the subtrochanteric region and distal femoral corticotomy, to permit the gradual realignment of the knee into the new weight-bearing axis produced by the proximal osteotomy. Total fixation time for the femoral reconstruction was two months. Five months after removal of the apparatus, the patient was returned to full function with a remarkably improved gait.

Adolescent↗
PubMed1991

Ilizarov apparatus for infected pseudarthrosis of the spine: a case report.

A case is presented of a 13-year-old girl with thoracic level myelomeningocele who developed an infected pseudarthrosis of the lumbar spine after an attempted kyphosectomy. The pseudarthrosis was successfully united through the use of special modifications of the Ilizarov apparatus. Rings and wires were applied to the iliac wings below and the thoracic laminae above the pseudarthrosis site. Preoperative planning was aided by a CT scan of the pelvis and spine. A cut-out foam mattress and a special wheelchair were used postoperatively to facilitate patient care.

Abscess↗
PubMed1990

Use of the Pavlik harness in congenital dislocation of the hip. An analysis of failures of treatment.

In twenty-five patients, the Pavlik harness failed to obtain or maintain reduction in thirty of thirty-five congenital dislocations of the hip. All of the patients had met the clinical criteria for use of the harness in our institution: they were less than seven months old, the femoral head pointed to the triradiate cartilage on anteroposterior radiographs that were made with the child wearing the harness, and they had no evidence of neuromuscular disease or teratological dislocation. These patients were compared with seventy-one patients (eighty-one dislocations) who had also been treated with the Pavlik harness and in whom a stable reduction was obtained and maintained. Statistically significant risk factors for failure of the harness included an absent Ortolani sign at the initial evaluation, bilateral dislocation, and an age of more than seven weeks before treatment with the harness was begun. All thirty hips in which the harness failed to obtain or maintain reduction had a subsequent attempt at closed reduction after preliminary Bryant traction. Fifteen of these hips were successfully reduced closed, but two later redislocated and needed an open reduction. The remaining fifteen hips needed an open reduction, and two redislocated and needed a second open reduction.

Age Factors↗
PubMed1990

Measurement of scoliosis and kyphosis radiographs. Intraobserver and interobserver variation.

Interobserver variations for measurements of the Cobb angle on radiographs of patients who had kyphosis were comparable with those on the radiographs of patients who had scoliosis. Four staff orthopaedists and one physical therapist measured eight radiographs that showed scoliosis and twenty that showed kyphosis. The measurements were made on two occasions and in random order. For scoliosis, the average difference between readings was 3.8 degrees, and 95 per cent of the differences were 8 degrees or less (range, 0 to 10 degrees). These findings were in keeping with those of other published reports. For kyphosis, the average difference between readings was 3.3 degrees, and 95 per cent of the differences were 7 degrees or less (range, 0 to 30 degrees). One investigator rated the kyphosis radiographs with respect to clarity. There was a trend to less variation with clearer radiographs, but this was not significant. The end-vertebrae were pre-selected for some radiographs and were freely chosen by the interpreter for others. Reliability was not significantly improved when the end-vertebrae of the curve had been pre-selected. Using the statistical method called tolerance limits, we determined that if one were to be 95 per cent confident that a measured difference represented a true change, the difference would have to be 10 degrees for scoliosis radiographs and 11 degrees for kyphosis radiographs. The probability that a measured difference is due to measurement error alone (that is, a false-positive reading) was calculated.

Analysis of Variance↗
PubMed1989

Frontal plane and sagittal plane balance following Cotrel-Dubousset instrumentation for idiopathic scoliosis.

Postoperative decompensation has been reported following Cotrel-Dubousset instrumentation for right thoracic idiopathic scoliosis. The authors examined balance in the frontal and sagittal planes in 53 patients to determine optimal levels for fusion. King et al Type II curves, particularly larger ones, shifted to the left when the thoracic curve was fused to the stable vertebra or just below. Most Type III curves balanced well regardless of the levels fused. One-third of all patients developed mild radiographic junctional kyphosis at the lower level instrumented, more commonly when instrumentation ended at or above T12. The authors recommend fusing one segment short of the stable vertebra in most Type II curves. Large Type II curves need both curves fused for optimal balance. Type III curves can be fused short of the stable vertebra.

Adolescent↗
PubMed1989

One-stage treatment of congenital dislocation of the hip in older children, including femoral shortening.

We reviewed the results of primary operative treatment in twenty-five patients (thirty-three hips) who were two years or older and had congenital dislocation of the hip. None of the patients had had previous treatment for the dislocation. Preliminary traction was not used in any patient. Femoral shortening and, in twenty-one hips, pelvic osteotomy were performed at the time of open reduction. At the most recent follow-up (average, three years and seven months), according to the radiographic classification system of Severin, there were seven excellent, seventeen good, and eight fair results; one hip had a poor result. Avascular necrosis developed in three of the thirty-three hips. At follow-up, these hips had a radiographic result of excellent, good, and fair, respectively. Twenty-one patients (twenty-eight hips) were reviewed with respect to range of motion and recovery from limb-length discrepancy. According to the rating system of Ferguson and Howorth, there were seventeen excellent, seven good, and three fair results; one hip had a poor result. It was concluded that children who are two years or older and who have a congenital dislocation of the hip can safely be treated with an extensive one-stage operation consisting of open reduction combined with femoral shortening and, often, pelvic osteotomy, without increasing the risk of avascular necrosis. The limb-length discrepancy that is produced by the shortening does not appear to cause a clinical problem.

Child↗
PubMed1988

Mechanical testing of spinal instrumentation.

Clinically, implant failure is often the result of fatigue from continuous cyclic loading. Because of the inadequacies of long-run cyclic testing, fatigue susceptibility of implants was investigated by means of strain measurements and stress analysis under physiologic loads. The implants were equipped with strain gauges during load-deformation testing, and the tensile stress (the component of stress-producing fatigue failure in metals) was calculated for that site on the implant. For metals most often implanted for spinal surgery, such as stainless steel and chrome-cobalt alloys, a stress exists, known as the endurance limit, below which failure will not occur, even if cycled indefinitely. By calculating the tensile stresses in an implant and relating them to the endurance limit, the implant's susceptibility to fatigue can be determined at the site of stress analysis without formal cyclic load testing.

Biomechanical Phenomena↗