2020 Volume 11 Issue 6 Pages 936-941
Purpose: There is no consensus of regarding the indication of surgical treatment of the less invasive decompression procedure for lumbar spinal stenosis (LSS). Although facet joint opening (FO) on preoperative computed tomography (CT) images has been reported as a parameter indicating segmental instability, there is no report on how FO affects on postoperative outcomes. The purpose of this study was to investigate risk factors for revision surgery after less invasive decompression surgery for LSS including FO by a minimum-5-year postoperative survey.
Materials and Methods: A total of 244 patients who underwent microscopic or microendoscopic decompression surgery for LSS and followed for ≥5 years were included in this study. We investigated revision lumbar surgeries at the same levels or other lumbar levels based on medical records. Revision surgeries due to postoperative hematoma or infection were excluded. FO was defined as a ≥2 mm opening on preoperative axial CT images at each lumbar intervertebral level. We evaluated the FO at index decompression levels and sum of FO-positive levels from L1-2 to L5-S. Risk factors for further surgeries were investigated among demographics, preoperative symptoms, and radiological parameters other than FO using univariate and cox proportional hazard regression analysis.
Results: There was 26 reoperations (10.7%) at a mean of 3.9 years after primary surgeries. FO at index decompression levels was significantly more frequent in patients with than without revision surgeries (69 and 39%, respectively, p=0.003). The sum of FO-positive levels among lumbar segments was significantly higher in patients with than without revision surgeries (2.0 and 1.2 levels, respectively, p=0.001). The cox proportional hazard regression analysis indicated that the sum of FO-positive levels among lumbar segments was one of the risk factors for revision surgery (p=0.003, adjusted hazard ratio: 1.47).
Conclusions: The FO of index decompression levels and sum of FO were associated with the need for further lumbar surgeries after less invasive surgery. FO might indicate not only segmental instability but also predictive parameter for progression of degenerative change.
