Dynamic Stabilization with an Interspinous Process Device (the Wallis System) for Degenerative Disc Disease and Lumbar Spinal Stenosis

Park, Yong Sook; Kim, Young Baeg; Lee, Dong Geol; Kim, Kyoung Tae; Nam, Taek Kyun

Abstract

OBJECTIVE
We used an interspinous process device, the Wallis system, to treat patients with disc disease or lumbar spinal stenosis and retrospectively assessed the clinical and radiological outcomes. METHOD: The patients were divided into two groups, one with herniated disc disease(HDD) and the other with lumbar spinal stenosis(LSS). Nineteen patients and fourteen patients were enrolled in the HDD and the LSS group, respectively. Preoperative and postoperative pain and activities of daily living(ADL) were assessed in each group. The anterior, posterior disc height and height of the neural foramen were measured. The degree of flexion, extension and lateral flexion were measured.
RESULTS
Both groups improved in pain and ADL after surgery. There were no significant changes in anterior, posterior disc height and height of the neural foramen after the operation in both groups. The change in coronal angle was statistically significant in the entire patient population. The kyphotic angle on the flexion lateral film was 6.1+/-4.1degrees preoperatively and 6.0+/-3.8degrees postoperatively in the entire patient population. Although it was not statistically significant, the kyphotic angle tended to decrease in the HDD group. The lordotic angle was 15.9+/-5.5degrees preoperatively and 13.5+/-6.3degrees postoperatively in overall patient population(from 15.5+/-3.9degrees to 14.0+/-2.7degrees in the HDD group and from 16.0+/-5.9degrees to 13.4+/-6.8degrees in the LSS group). The lordotic angle was significantly decreased in the LSS group.
CONCLUSIONS
Interspinous process devices can induce favorable motion changes on lumbar motion such as decreasing tendency of flexion in the HDD group and decreasing tendency of extension in the LSS group. It suggests that interspinous devices may act as dynamic stabilizers in patients with degenerative disc disease and lumbar spinal stenosis.