TRANSPEDICULAR DECANCELLATION FOR THE CORRECTION OF RIGID THORACIC KYPHOSIS

Abstract

Rigid angular kyphotic deformities of the spine have been corrected by staged anterior and posterior procedures. This paper evaluates the efficacy of single stage transpedicular decancellation, vertebral column mobilization and spinal shortening in the correction of rigid THORACIC kyphotic deformities in adolescent patients.

Between 1993 and 1999, 21 patients with rigid kyphosis underwent deformity correction using the above procedure. The deformity was thoracic in 6 patients, thoraco-lumbar in 14 and lumbar in one patient. This report focuses on 6 patients with thoracic deformity. The etiology in 5 patients was due to tuberculosis while one patient had a congenital anomaly. There were 4 females and 2 male patients. The average age was 12 years. The average kyphosis was 75 degrees (38 – 135 degrees). Of the 6 patients, 2 had preoperative paraplegia. All cases were assessed using CT and MRI scans in addition to plain radiographs. The surgical technique utilized the principle of transpedicular decancellation through a single posterior midline exposure in the prone position. Following complete decancellation of the apical vertebrae, the proximal and distal vertebral column was adequately mobilized to enable spinal shortening along with anterior translation. Segmental spinal instrumentation was used to achieve stable fixation.Intraoperatively, the wake-up test was used to assess the neurological function. This was followed by anterior interbody fusion and posterolateral fusion. At an average follow-up of 36 months, average kyphosis correction was 61% and all cases were adequately fused. Both cases with paraplegia recovered completely. The average loss of correction was 6 degrees. One patient developed hyperlordosis below the corrected level. This was revised by extending the spinal fixation to include the lower levels. In conclusion, the above procedure is used as a last resort for correction of rigid angular deformities. It is a safe but demanding procedure. Spinal column shortening is essential to avoid neurologic compromise and balance the column.