D S Bradford

The selection of fusion levels in thoracic idiopathic scoliosis.

From the material and data reviewed in our study of 405 patients, it appears that postoperative correction of the thoracic spine approximately equals the correction noted on preoperative side-bending roentgenograms. Selective thoracic fusion can be safely performed on a Type-II curve of less than 80 degrees, but care must be taken to use the vertebra that is neutral and stable so that the lower level of the fusion is centered over the sacrum. The lumbar curve spontaneously corrects to balance the thoracic curve when selective thoracic fusion is performed and the lower level of fusion is properly selected. In Type-III, IV, and V thoracic curves the lower level of fusion should be centered over the sacrum to achieve a balanced, stable spine.

STIMULATION OF MATURE CANINE INTERVERTEBRAL DISC BY GROWTH FACTORS

Although the role of growth factors in the regulation of phenotype, maintenance, and repair of cartilaginous tissues has been extensively evaluated, the response of intervertebral disc to growth factors has not been investigated. A tissue culture system for anular, transitional, and nuclear regions of mature canine intervertebral disc was devised to assess the proliferatiye response, as determined by 3H-thymidine incorporation, and the bio-synthetic response, assayed by 35S-sulfate incorporation into proteoglycan, of these tissues to growth factors. The culture system achieved steady-state conditions in serum-free mediums at 4 days and was perturbed by plasma-derived equine serum, fetal calf serum, insulin-like growth factor-1, epidermal growth factor, fibroblast growth factor, and transforming growth factor-β. Incorporation rates by the tissue regions of up to five times the control rate were recorded; the nucleus and transition zone responded more than anulus. Transforming growth factor-p and epidermal growth factor elicited greater responses than fibroblast growth factor; insulin-like growth factor-1 produced a marginally significant response in the nucleus and no response in the anulus and transition. The intervertebral disc appeared to respond to the growth factors differently than cartilage, and this may represent inherent differences in cell biology. The biologic significance and basis of these responses require further evaluation. However, the responses observed, particularly in the nucleus and transition zone suggest the possibility that disc repair can be modulated by growth factors. A therapeutic approach to degenerative disc disease involving enhanced tissue repair by exogenous growth factors would be of great clinical significance.

Management of severe spondylolisthesis in children and adolescents.

Forty-three patients with a fifth lumbar-first sacral spondylolisthesis of 50 per cent or greater were reviewed. Four had been treated non-operatively; eleven, by arthrodesis; eighteen, by decompression and arthrodesis; and ten, by reduction and arthrodesis. The angle of slipping (measurement of the kyphotic relationship of the fifth lumbar to the first sacral vertebra) was found to be as important a measurement as the percentage of slipping in measuring instability and progression of slipping. Hamstring tightness did not correlate with neural deficit. Arthrodesis alone, even in the presence of minor neural deficits, tight hamstrings, or both, gave relief of pain and resolution of neural deficits and tight hamstrings. Our experience with a limited number of patients suggests that management by postoperative extension casts may achieve a significant reduction in percentage of slipping and in angle of slipping. Progression of the spondylolisthesis may occur following a solid arthrodesis.

Results of spinal arthrodesis with pedicle screw-plate fixation.

Sixty-one patients were followed for an average of thirty months (range, twenty-four to thirty-five months) after arthrodesis of the lumbar or lumbosacral spine with pedicle screw-plate fixation for painful degenerative arthritis, spondylolisthesis, or pseudarthrosis. The patients rated the clinical result according to an analog scale. Most patients reported a marked decrease in pain and an increase in function, and two-thirds were able to work full time. The result of the operation was regarded as a clinical failure if the patient considered it so, if an additional operation had been done, or if the functional and pain scores were not good (that is, if the patient was not able to work full time and the rating for pain was more than 5 of 10 points). Seventeen (28 per cent) of the patients were considered to have a clinical failure, with the lowest rate (20 per cent) for patients who had painful degenerative arthritis and the highest rate (47 per cent) for patients who had had a pseudarthrosis before the operation. The rate of fusion was 90 per cent in patients who had painful degenerative disease, 93 per cent in patients who had spondylolisthesis, and 65 per cent in patients who had had a pseudarthrosis preoperatively.

Decompensation After Cotrel-dubousset Instrumentation of Idiopathic Scoliosis

Spinal decompensation after corrective surgery for scoliosis appears to be a significant problem after Cotrel-Dubousset instrumentation (CDI). CDI produces torsional changes in the instrumented and uninstrumented spine that could result in spinal imbalance. Preoperative and postoperative three-dimensional analysis including computed tomography (CT) scans to measure vertebral rotation and segmental rotation were performed to evaluate the importance of torsional changes. Moe/King Type II deformities had a substantially greater risk of imbalance. Deformities instrumented over fewer spinal segments were less likely to decompensate. Specifically, instrumentation excluding the mobile transition segment, determined by maximum segmental rotation and segmental Cobb angle, was likely to decompensate. Derotation and deformity correction excessive in relation to preoperative side bending flexibility and segmental rotation frequently resulted in imbalance. Spinal imbalance after CDI can be reduced by avoiding overcorrection and inclusion of mobile transition segments.

One-stage anterior and posterior hemivertebral resection and arthrodesis for congenital scoliosis.

Seven children who had congenital scoliosis due to a single, fully segmented lumbar hemivertebra were treated with single-stage anterior and posterior vertebral resection and arthrodesis. The scoliosis averaged 47 degrees preoperatively, 14 degrees postoperatively, and 15 degrees (approximately 70 per cent correction) after an average follow-up of 45.6 months. Four patients had thoracolumbar kyphosis preoperatively, and it remained unchanged at the most recent follow-up examination. Postoperatively, a cast was worn for twelve to sixteen weeks, after which a brace was applied. There were no neurological deficits, infections, deaths, or pseudarthroses. The combined procedure was well tolerated and, in the limited period of follow-up, the congenital scoliosis did not progress.

Post-traumatic kyphosis. A review of forty-eight surgically treated patients.

We reviewed the cases of forty-eight patients who were treated surgically for symptomatic post-traumatic kyphosis of the thoracic or lumbar spine six months or longer after the initial injury. Presenting signs and symptoms included pain in 94 per cent, progression of kyphosis in 46 per cent, instability in 36 per cent, and increasing neural deficit in 27 per cent. Twenty-four patients had had a prior laminectomy. Posterior fusion (sixteen patients) and combined anterior and posterior fusion (twenty patients) always resulted in primary fusion. Anterior fusion alone was attempted in twelve patients, but failed in six. The average final correction of the deformity was 26 per cent. Pain was reduced significantly in 31 per cent of the patients and was relieved completely in 67 per cent. Fourteen of the forty-eight patients also had an anterior decompression, of whom five were neurologically improved, four were unchanged or stabilized, and four were immediately worse after operation. One patient was neurologically stable for twenty-three months postoperatively and then deteriorated again. No patients were neurologically improved following posterolateral decompression or repeat exploratory laminectomy.

Surgical treatment of adult scoliosis. A review of two hundred and twenty-two cases.

We evaluated the cases of 222 patients older than twenty years in whom scoliosis was the primary diagnosis. No patient had had prior surgical treatment. The diagnoses were idiopathic scoliosis in 160 patients, paralytic scoliosis in forty-four, and congenital scoliosis in eleven, and there were miscellaneous diagnoses in seven patients. The average age of the patients when first seen was 30.7 years. The indications for operation were pain, progression of the curve, magnitude of the curve, and cardiopulmonary symptoms. Preoperative traction, including halo-femoral traction, did not result in increased correction when compared with the initial supine side-bending roentgenogram. A one-stage fusion was performed in 174 patients and multiple-stage procedures, in forty-eight patients. At an average follow-up of 3.6 years the average loss of correction was 6.2 degrees, 68 per cent of the patients were free of pain, and a solid fusion had been obtained in all but six patients. Complications developed in 53 per cent of the patients, the most common problems being pseudarthrosis, urinary tract infection, wound infection, instrumentation problems, a pulmonary disorder, and loss of lumbar lordosis. Paraplegia occurred in one patient. The over-all mortality rate was 1.4 per cent. Complications increased with age, and the highest mortality rate was in patients with congenital scoliosis who had cor pulmonale.

Scheuermann's Kyphosis and Roundback Deformity: Results Of Milwaukee Brace Treatment

Review of 223 patients with Scheuermanns kyphosis and postural roundback showed that seventy-five patients with this deformity who had completed Milwaukee brace treatment had their kyphosis improved by an average of 40 per cent; their vertebral wedging, by an average of 41 per cent; and their lordosis, by an average of 36 per cent. Severity of kyphosis (greater than 65 degrees), skeletal maturity (as shown by iliac epiphysis closure), and vertebral wedging averaging more than 10 degrees were factors which limited the amount of correction obtained with the Milwaukee brace. The presence of scoliosis did not affect the end result.

Spine deformity in neurofibromatosis. A review of one hundred and two patients.

The natural history, associated anomalies, and response to operative and nonoperative treatment were reviewed in 102 patients with neurofibromatosis and spine deformity. Eighty patients were found to have curvatures associated with dystrophic changes in the vertebrae and ribs. The presence of dystrophic changes such as rib penciling, spindling of the transverse processes, vertebral scalloping, severe apical vertebral rotation, foraminal enlargement, and adjacent soft-tissue neurofibromas was found to be highly significant in prognosis and management. Brace treatment of dystrophic curves was unsuccessful. Posterior fusion, with or without internal fixation, was the procedure of choice for problems due purely to scoliosis. Patients with dystrophic kyphoscoliosis required both anterior and posterior fusion to achieve stability. Sixteen patients had compression of the spinal cord or cauda equina.