John G. Birch

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.

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°) 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 Propionlbacterium acnes, staph epidermidis, or staph coagulese 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.

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.

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 implants susceptibility to fatigue can be determined at the site of stress analysis without formal cyclic load testing.

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.

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

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° before traction (range 63°–100°) to 55° 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.

Stability of external circular fixation: a multi-variable biomechanical analysis

OBJECTIVE: To determine how the manipulation of the parameters of fixation and components of the circular external frame could improve and maintain optimal stability of bone fragments. DESIGN: We performed a multi-parametric biomechanical analysis of the extrinsic parameters effecting bone fragment stabilization. Results of testing are presented as a percent change in stiffness due to the manipulation of frame components and their interaction with other fixation parameters. BACKGROUND: Although there have been investigations of the biomechanical characteristics of circular external fixation, they have been limited to either individual frame components or full frame comparisons. Therefore, these studies did not provide a comprehensive understanding of how the manipulation of circular fixator components influences bone fragment stability. METHODS: Mechanical testing was performed in three phases examining the effect of numerous components including ring diameter, wire angle, ring separation, etc. on axial, torsional and bending stiffness. RESULTS: For phase I (single ring) and phase II (double-ring block), ring diameter was the most significant factor affecting axial and torsional stiffness, while wire angle, ring separation, and their interaction had the most influence on bending stiffness. Phase III (two double-ring blocks) showed that ring positioning with respect to the osteotomy site had the most affect on bending and torsional stiffness while axial stiffness was non-linear and dependent upon the applied load. CONCLUSIONS: The stability of bone fragments within a circular external fixator is affected by manipulation of the parameters of fixation or individual components of the frame. The contribution of each component to overall bone fragment stability is dependent upon the mode of loading. The changes in overall stability of bone fragments are dependent not only on the individual frame components but also upon their interaction with other parameters of fixation. RELEVANCE: Understanding how the manipulation of individual frame components will affect overall bone fragment stabilization will allow the surgeon to better control the stability of bone fragments for each clinical situation.

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 of 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.

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.

Use of the Ilizarov Method to Correct Lower Limb Deformities in Children and Adolescents

Abstract The introduction to the West in the early 1980s of the Ilizarov circular external fixator and method resulted in rapid advances in limb lengthening, deformity correction, and segmental long‐bone defect reconstruction. The mechanical features of and biologic response to using distraction osteogenesis with the circular external fixator are the unique aspects of Ilizarovs contribution. The most common indications for children and adolescents are limb lengthening and angular deformity correction. Surgical application and postoperative management of the device require diligent attention to detail by both patient and surgeon. Also required of the surgeon is a thorough appreciation of the basic principles of the apparatus, mechanical axial realignment, potential complications, and biologic response to stretching.