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Biomedical subjects

J G Birch

Publications and source records attributed to J G Birch.

36 records · Page 2Linked to original sources
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↗
PubMed1988

Cotrel-Dubousset instrumentation in idiopathic scoliosis. A preliminary report.

This is a preliminary report on Cotrel-Dubousset (CD) instrumentation for the surgical management of idiopathic thoracic scoliosis. From September 1985 through April 1986, 37 patients were treated at the authors' hospital, by posterior spinal fusion with CD instrumentation. Twelve patients had surgical treatment of spinal deformity associated with other disorders or had revision surgery. The remaining 25 patients, with no prior surgery, were diagnosed as having juvenile or adolescent idiopathic scoliosis. After operation, this group of patients was routinely noted to have significant improvement in rib deformity. This is associated with the rotational correction achieved with CD instrumentation and contrasts with the minimal rib deformity correction with Harrington instrumentation documented by some workers. In this series, no rib resections have been necessary in conjunction with CD instrumentation. No postoperative external immobilization was used. Ambulation began on the second postoperative day, and patients were discharged five to seven days after operation. Gradual resumption of normal activities was allowed at six weeks, and full activities, other than contact sports, after three months.

Child↗
PubMed1984

Surgical anatomy of selected physes.

Recent advances have allowed successful resection of partial physeal arrest in children whose physes have been damaged by trauma, infection, irradiation, and other causes. Underlying physeal anatomy and the relationship of overlying structures to the physis are vital in preparing for precise surgical excision of the bony bar. The cadaver of a 5-year-old child was dissected with special emphasis on the surgical accessibility of the physes and adjacent metaphyses of the distal radius, distal femur, proximal tibia, and distal tibia and fibula. The physis of the distal radius was found to be completely extracapsular. The synovial reflection of the suprapatellar pouch obscured portions of the anterior, medial, and lateral aspects of the distal femur. The capsular attachment extended to the level of the physis anteriorly and posteriorly. The capsular attachment to the medial distal femur was more distal and peripheral than to the lateral. The insertion of the adductor magnus tendon medially and the intermuscular septum laterally served as landmarks to the level of the physis. The physis of the proximal tibia was completely extracapsular. The posterior aspects of the physis and the metaphysis were obscured in the midline by the popliteus muscle, and this posterolateral region was the least surgically accessible of any of the regions studied. The distal tibial physis was entirely extracapsular. The anterior and posterior tibiofibular ligaments inserted across the anterolateral and posterolateral aspects of the physis of the distal fibula. This physis on its medial aspect lay intraarticularly at the level of the articular cartilage of the distal tibia.(ABSTRACT TRUNCATED AT 250 WORDS)

Cartilage, Articular↗
PubMedDate not supplied

Intraoperative SSEP monitoring during external fixation procedures in the lower extremities.

The efficacy of somatosensory evoked potentials (SSEPs) to detect acute peripheral nerve injury during external-fixator application in the lower extremities was evaluated in 40 children with 42 Ilizarov surgical procedures. The study included patients who were either clinically normal or who had preexisting neuropathy but consistent and reliable SSEP responses preoperatively. SSEPs were recorded from the popliteal fossa and lumbar regions after alternating stimulation of the peroneal and posterior tibial nerves at the ankle. SSEP changes due to anesthesia, Ilizarov apparatus application, and other intraoperative variables are described. Significant deterioration or total loss of SSEP response during surgery occurred in four cases. Two of these patients were normal preoperatively and had symptoms of neurologic deficit postoperatively; the other two had exacerbations of pre-existing neuropathy. In general, the peroneal nerve was at greater risk for injury during surgery. SSEP monitoring proved to be technically feasible in external-fixation procedures on the lower extremities and may be a practical tool for detection of intraoperative nerve compromise.

Acute Disease↗
PubMedDate not supplied

Monitoring peripheral nerve function during external fixation of upper extremities.

Limb lengthening of the upper extremity using external fixation devices is associated with a high risk of neurovascular impairment. To aid early detection of nerve injury, intraoperative monitoring of neural function was performed in five patients undergoing Ilizarov-type circular external-fixator application. The apparatus was applied to the humerus in two cases and to the forearm in the other three cases. The function of ulnar, median, and radial nerves was assessed continuously throughout the surgery by using sensory-evoked potential (SEP) monitoring technique. The responses were elicited by stimulation of these nerves in the distal forearm with recording at Erb's point and over the anterior cervical spine. During apparatus application, radial-response attenuation was identified in two instances. No corrective actions were performed in one case, and the patient had symptoms of radial nerve deficit postoperatively. In the other case, prompt removal of the offending half-pin after the detection of electrophysiologic abnormalities resulted in subsequent response restoration and the avoidance of postoperative nerve dysfunction. Sensory-evoked potential monitoring proved to be a reliable indicator of nerve compromise during external fixation of upper extremities and may be considered a valuable surgical adjunct.

Adolescent↗
PubMedDate not supplied

Splitting of the intervertebral disc in spondylolisthesis: a magnetic resonance imaging finding in two cases.

Two patients with grade III spondylolisthesis of L5 on S1 underwent magnetic resonance imaging (MRI) as part of their preoperative evaluation. The nucleus pulposus of the involved intervertebral disc was noted to be divided into anterior and posterior halves. The signal intensity of the involved nucleus pulposus was decreased, a finding correlated to degenerative changes of the disc material. Moderate narrowing of the thecal sac was noted at the level of spondylolisthesis. Both patients underwent in situ posterolateral spinal fusion from L4 to S1 without decompression. We were not able to correlate the MRI findings to etiology of pain in spondylolisthesis.

Adolescent↗
PubMedDate not supplied

Teratologic dislocation of the hip.

We reviewed 27 teratologic hip dislocations in 17 patients. Four hips underwent closed reduction, 10 hips had medial adductor open reduction, 9 hips had iliofemoral open reduction, and 4 hips had iliofemoral open reduction and femoral shortening. Avascular necrosis occurred in 48%, redislocation in 19%, and subluxation in 22% of the hips. Results were best in those hips treated by anterior open reduction and femoral shortening and worst in those having closed reduction. Poor results correlated with multiple other involved joints, hypotonia, developmental delay, and poor head control.

Arthrogryposis↗
PubMedDate not supplied

Slipped capital femoral epiphysis: still an emergency.

Two case histories are presented in which acute progression of slipped capital femoral epiphysis occurred after a radiographic diagnosis of chronic slipped capital femoral epiphysis had been made. The importance of recognizing the potential for acute progression of a slipped epiphysis and the need for prompt orthopedic intervention are emphasized.

Child↗
PubMedDate not supplied

Spinal deformity in Marfan syndrome.

Fourteen patients with classic Marfan syndrome and spinal deformity treated at Texas Scottish Rite Hospital for Crippled Children (Dallas, TX) after 1975 have been conservatively treated to maturity or are at least 2 years after spinal fusion. Brace treatment was successful in one of nine patients. Nine patients underwent fusion. Three had a solid fusion, two lost 20 degrees of correction, and four required revision for multiple pseudarthroses. These latter four all had or developed a kyphotic deformity. Although Marfan syndrome patients can achieve solid fusion, they require massive bone graft, secure segmental internal fixation, and careful observation for pseudarthrosis. Kyphotic deformities require anterior fusion.

Adolescent↗
PubMedDate not supplied

Spontaneous resolution of congenital anterolateral bowing of the tibia.

In a series of 43 patients diagnosed with congenital anterolateral bowing of the tibia or congenital pseudarthrosis of the tibia treated between 1980 and 1992, the deformities corrected themselves spontaneously in five patients who had no other congenital abnormalities or evidence of neurofibromatosis. At an average follow-up of 58 months (average age at follow-up 80 months), the only residual deformity seen was a limb-length discrepancy in patients with unilateral involvement. In patients with subperiosteal callus formation on the posteromedial concavity of this deformity and an uninvolved fibula, no treatment appears necessary, as this deformity will spontaneously resolve.

Child, Preschool↗
PubMedDate not supplied

Outcome of ultrasonographic hip abnormalities in clinically stable hips.

A retrospective review was performed of 192 newborn hips in 112 patients referred for hip evaluation. The average age at presentation was 12.7 days, with average radiographic follow-up of 15.9 months. Inclusion criteria for our study were a normal physical examination of the hip without evidence of instability and an ultrasound examination that was considered abnormal. Pavlik harness treatment was chosen at the discretion of the treating physician. At final follow-up, dysplasia was defined as greater than two standard deviations above the mean acetabular index (AI) for age. Group I consisted of 43 hips that had Pavlik treatment, and group II consisted of 149 hips that did not receive treatment. There was no difference in these two groups with respect to risk factors for dysplasia or the initial abnormalities seen on ultrasound evaluation, although patients in group I had less coverage of the femoral head during stress maneuvers. No hip in group I and two (1.3%) hips in group II were considered dysplastic (AI > 2 SD) at final radiographic follow-up (p > 0.10). There was no correlation between the severity of the ultrasound abnormality at birth and the subsequent presence of dysplasia (p > 0.10). The two hips considered dysplastic on radiograph were not being actively treated. When the hip examination of a newborn hip younger than 1 month is normal, a screening ultrasound does not appear to predict accurately subsequent hip dysplasia. In this specific setting, an initial screening ultrasound may be too sensitive and does not appear warranted.

Analysis of Variance↗
PubMedDate not supplied

Efficacy of perioperative halo-gravity traction in the treatment of severe scoliosis in children.

SUMMARY: Perioperative halo traction was used in the treatment of severe scoliosis in 19 children. Diagnoses included neuromuscular, idiopathic, and congenital scoliosis. Traction was transferable between the bed and a walker or wheelchair. Thirteen patients had prior spinal surgery, and most required osteotomy. Traction was used for 6 to 21 weeks. All patients underwent spinal fusion surgery after traction, with instrumentation used in 15 patients. Improvement was achieved in all patients. The Cobb angle improved 35% from an average 84 degrees before traction (range 63 degrees -100 degrees ) to 55 degrees preceding fusion. Trunk decompensation improved in all patients. Trunk height increased 5.3 cm in traction. Response to traction did not correlate with diagnosis, patient age, or prior surgery. There were no neurologic complications. Perioperative halo-gravity traction improves trunk balance and frontal and sagittal alignment in children with severe spinal deformity. Surgical fusion was enhanced by the improved alignment, and neurologic injury was avoided.

Activities of Daily Living↗
PubMedDate not supplied

Syringomyelia and scoliosis in children.

We reviewed 28 patients < 18 years of age with scoliosis and syringomyelia. Children with scoliosis and syringomyelia had an equal incidence of left- and right-sided curves with a normal sagittal alignment. Most were first seen at Risser 0 with significant curves, and curve progression occurred in half of the patients. Bracing was not effective in preventing curve progression. Neurologic signs, present in most children, stabilized after syrinx drainage. Neither the sex or age of the child, nor the type of curve, nor the drainage of the syrinx was predictive of curve progression.

Adolescent↗
PubMedDate not supplied

Focal fibrocartilaginous dysplasia in the upper extremity.

Focal fibrocartilaginous dysplasia is a benign lesion known to cause tibia vara in young children. To date, this lesion has been recognized in only the proximal medial tibia. This study reports two additional cases of focal fibrocartilaginous dysplasia occurring in the long bones of the upper extremity. The clinical presentation, radiographic appearance, histopathology, and natural history of focal fibrocartilaginous dysplasia in the humerus and ulna are analogous to published descriptions involving the tibia. Spontaneous resolution of the lesion and the resultant angular deformity is possible but not entirely predictable. Limb-length discrepancy should be anticipated.

Arm↗