Benefits and Weaknesses of Interspinous Devices in Elderly Patients with Lumbar Spinal Stenosis: Comparative Study of Interspinous U and Decompression Surgery Alone

Park, Yong Sook; Kim, Young Baeg; Kim, Kyoung Tae

Abstract

OBJECTIVE
Several types of interspinous process(ISP) devices have the common goal of limiting lumbar extension. In this study, we selected patients aged older than 60 years with lumbar spinal stenosis and assessed whether ISP devices are more beneficial in elderly patients with lumbar spinal stenosis than simple decompression.
METHODS
Eighteen patients were treated with the Interspinous U device, and 17 patients were treated with decompre- ssion alone during the same period. Clinical results were assessed using the pre- and postoperative visual analogue scale(VAS) and activities of daily living(ADL). Radiologic results were assessed according to pre-and postoperative anterior disc height, posterior disc height, foraminal height, spondylolisthesis, segmental coronal angle and lordotic angle at the treated level.
RESULTS
The mean age of the patients in the interspinous device group was 66.9 years(range 60-78 years), and the mean age of the patients in the decompression group was 70.6 years(range 60-80 years). The mean pre- and postoperative VAS scores were 8.5 and 3.8, respectively, in interspinous devices group and 7.7 and 2.5 in the decompression group. Both groups of patients showed significant improvement in their VAS and ADL scores in comparison with their preoperative scores. Radiologically, there were no significant differences in anterior and posterior disc height or foraminal height in the interspinous devices group. Coronal and lordotic angles were reduced postoperatively in the device group but not in the decompression group. Listhesis at the treated level was significantly aggravated in both groups.
CONCLUSIONS
The ISP device was helpful in alleviating pain and improving ADL performance in elderly patients with lumbar spinal stenosis. It corrected segmental scoliosis and restricted extension. However Interspinous U may induce spondy- lolisthesis and do not prevent further displacement of preexisting spondylolisthesis. There should be careful selection to apply of this device in elderly patients.