Spinaplasty following lumbar laminectomy for multilevel lumbar spinal stenosis to prevent iatrogenic instability

Background: Iatrogenic instability following laminectomy occurs in patients with degenerative lumbar canal stenosis. Long segment fusions to obviate postoperative instability result in loss of motion of lumbar spine and predisposes to adjacent level degeneration. The best alternative would be an adequate decompressive laminectomy with a nonfusion technique of preserving the posterior ligament complex integrity. We report a retrospective analysis of multilevel lumbar canal stenosis that were operated for posterior decompression and underwent spinaplasty to preserve posterior ligament complex integrity for outcome of decompression and iatrogenic instability. Materials and Methods: 610 patients of degenerative lumbar canal stenosis (n=520) and development spinal canal stenosis (n=90), with a mean age 58 years (33-85 years), underwent multilevel laminectomies and spinaplasty procedure. At followup, changes in the posture while walking, increase in the walking distance, improvement in the dysesthesia in lower limb, the motor power, capability to negotiate stairs and sphincter function were assessed. Forward excursion of vertebrae more than 4 mm in flexion-extension lateral X-ray of the spine as compared to the preoperative movements was considered as the iatrogenic instability. Clinical assessment was done in standing posture regarding active flexion-extension movement, lateral bending and rotations. Results: All patients were followed up from 3 to 10 years. None of the patients had neurological deterioration or pain or catch while movement. Walking distance improved by 5-10 times, with marked relief (70-90%) in neurogenic claudication and preoperative stooping posture, with improvement in sensation and motor power. There was no significant difference in the sagittal alignment as well as anterior translation. Two patients with concomitant scoliosis and one with cauda equine syndrome had incomplete recovery. Two patients who developed disc protrusion, underwent a second operation for a symptomatic disc prolapse. Conclusion: Spinaplasty following posterior decompression for multilevel lumbar canal stenosis is a simple operation, without any serious complications, retaining median structures, maintaining the tension band and the strength with least disturbance of kinematics, mobility, stability and lordosis of the lumbar spine.