Neurological deficit after surgery for spinal deformity is a rare but devastating complication. Factors that have been associated with a post surgical deficit are congenital curves, large curves, kyphotic deformities, anterior and posterior surgery, ligation of multiple anterior vessels and hypotension; controlled or otherwise. Intra operative wake up tests have been used alone or in combination with spinal cord monitoring: to detect evolving neurological deficit in spinal deformity surgery. Despite these checks, major neurological deficits still occur post surgery. This is a report of two cases with normal intra operative wake up tests, but developed neurological deficit twelve hours after the end of surgery.
The Pedriolle torsion meter is an established method of vertebral rotation assessment in scoliosis. However, the assessment of scoliosis by this method is static and indirect. The objective of this study is to compare the accuracy of a direct method of assessing scoliosis rotation by fluoroscopy compared to the Pedriolle torsion meter. Secondly, to determine that vertebral body rotation changes with supine posture compared to erect position. Eight volunteers with idiopathic scoliosis were assessed for the apical vertebral rotation with this method and the Pedriolle torsion meter. These patients were also assessed in the supine and erect position with the fluoroscopic method to determine if the apical vertebral rotation would change with posture. The mean Cobb angle of the curves was 62.8 degrees (range 45 degrees to 86 degrees). The mean apical vertebral rotation in a standing position was assessed to be 21.5 degrees by Pedriolle torsion meter and 29 degrees by the fluoroscopic method. This difference was not statistically significant by the student t-test. In most patient, the rotation of vertebrae improved by a varying degree ranging from none to 24 degrees in the supine position. In conclusion, the fluoroscopic method is an alternate mean of measuring vertebrae rotation in idiopathic scoliosis, with comparable accuracy to the Pedriolle torsion meter method. The amount of vertebral rotation changes with posture of the patient.
We studied the curve progression of untreated curves presenting to the Scoliosis Service of Hospital Kuala Lumpur. One hundred and fifty-two (152) patients were included in this study. The median rate of curve progression of idiopathic scoliosis curves was 7.03 degrees per year, for neuromuscular scoliosis curves was 17.39 degrees per year; and congenital scoliosis curves were 3.67 degrees per year. These rates are similar to the reported rates in the literature. Data for sixty-one (61) surgically treated patients were reviewed to determine the early curve correction of the curves of different aetiology. The mean age of surgery was 14.15 years old, the mean preoperative curve size was 71.61 degrees; and the mean postoperative curve size was 43.78 degrees. The mean duration of follow up after surgery was 2.44 years. The revision and removal of instrumentation rate was 8.3%.
Non-traumatic, progressing sagittal plane deformities are uncommon, but can lead to neurological deficit if untreated. The currently used Cobb method in assessing sagittal spinal curves is based on measuring the tilt of the end vertebrae. This study describes a method which quantifies the apex of the sagittal curve based on the apical quality as measured by the radius of curvature. Both this and the Cobb methods are compared to determine which has relevance in determining neurological deficit. Radiographs of 36 consecutive patients diagnosed with congenital kyphosis were reviewed. Twenty-four had normal neurology and 12 had neurological deficit as a result of sagittal curve progression. Both groups of patients had their weight bearing lateral radiographs analysed to measure the sagittal curve by the usual Cobb method and the Radius of Curvature method. There was no difference for the Cobb values for negative neurology and patients with positive neurological deficit (p = 0.3). There was a difference in these two groups when the radius of curvature method was used (p < 0.0005). The Radius of Curvature method has more relevance than Cobb method in quantifying sagittal plane deformity in congenital kyphosis when assessing neurological deficit.