Treatment of neurogenic claudication by interspinous decompression: application of the X STOP device in patients with lumbar degenerative spondylolisthesis

Object. Interspinous process decompression (IPD) theoretically relieves narrowing of the spinal canal and neural foramen in extension and thus reduces the symptoms of neurogenic intermittent claudication (NIC). The purpose of this study was to compare the efficacy of IPD with nonoperative treatment in patients with NIC secondary to degenerative spondylolisthesis. Methods. The authors conducted a randomized controlled study in patients with NIC; they compared the results obtained in patients treated with the X STOP IPD device with those acquired in patients treated nonoperatively. The X STOP implant is a titanium alloy device that is placed between the spinous processes to reduce the canal and foraminal narrowing that occurs in extension. In a cohort of 75 patients with degenerative spondylolisthesis, 42 underwent surgical treatment in which the X STOP IPD device was placed and 33 control individuals were treated nonoperatively. Patients underwent serial follow-up evaluations. The Zurich Claudication Questionnaire (ZCQ), 36-Item Short Form Health Survey (SF-36), and radiographic assessment were used to determine outcomes. Two-year follow-up data were obtained in 70 of 75 patients. Statistically significant improvement in ZCQ and SF-36 scores was seen in X STOP device-treated patients but not in the nonoperative control patients at all postoperative intervals. Overall clinical success occurred in 63.4% of X STOP device-treated patients and only 12.9% of controls. Spondylolisthesis and kyphosis were unaltered.. Conclusions. The X STOP device was more effective than nonoperative treatment in the management of NIC secondary to degenerative lumbar spondylolisthesis.