Operative Treatment of Lumbar Foraminal and Extraforaminal Lesions

<p>  Objective : Lumbar foraminal or extraforaminal lesions account for 8-11% of all cases of lumbar canal stenosis. There is no consensus on the preferred surgical procedure for these lesions. To obtain adequate decompression of the nerve root, the partial or total removal of the facet joint is necessary. Some surgeons use decompression surgery alone, while others advocate the decompression procedure combined with spinal fixation.</p><p>  The authors retrospectively investigated the results of surgery for lumbar foraminal or extraforaminal lesions at our institute.</p><p>  Methods : Between January 2006 and December 2013, 86 patients with lumbar foraminal or extraforaminal lesions underwent surgery in our institute. Patients with reoperation, multiple level lesions, and spondylolysis were excluded from this study. The minimum postoperative follow-up time was 1 year. The Japanese Orthopedic Association (JOA) score and visual analogue scale (VAS) for back and leg pain were evaluated pre- and postoperatively. Dynamic slip angle, dynamic slip distance, and Cobb angle were measured by using standing X-ray films pre- and postoperatively. Patients with≧10° preoperative Cobb angle were defined as the “DLS group” and those with<10° were defined as the “non-DLS group” .</p><p>  Results : The preoperative JOA score (14.2) and VAS for back (5.4) and leg pain (6.9) were significantly improved to 20.7, 3.0, and 2.5, respectively, at 1 year after surgery. Postoperative progression of scoliosis (≧5°) occurred in 27.3% of the DLS group, which was higher than that in the non-DLS group (p=0.028). In the non-DLS group, no significant difference in the JOA score or VAS improvement rate was noted between the various operative procedures. On the contrary, in the DLS group, the JOA score improvement ratio was worse in patients who underwent decompression surgery alone than in patients who underwent spinal fixation. The Cobb angle increased significantly in patients who underwent decompression surgery alone and in those with unilateral pedicle screw fixation, compared with those who underwent interbody fusion and bilateral pedicle screw fixation.</p><p>  Conclusion : Microscopic decompression surgery alone can achieve satisfactory results for patients with foraminal or extraforaminal lesions when spinal instability or scoliosis (Cobb angle≧10°) is not apparent. On the other hand, patients with scoliosis have the potential risk of postoperative progression of scoliosis with a poor outcome. The authors recommend adequate decompression combined with interbody fixation and bilateral pedicle screw fixation for patients with DLS (Cobb angle≧10°).</p>