Spinous process osteotomy to facilitate the access to the spinal canal when decompressing the spinal canal in patients with lumbar spinal stenosis

Abstract

Study design: Retrospective study.

Purpose: The main purpose of this study was to investigate the union-rate of the spinous process after performing a spinous process osteotomy and whether union affects the clinical results after surgery.

Overview of literature: In the present study, spinous process osteotomy was used to facilitate access to the spinal canal when performing a decompressive procedure for lumbar spinal stenosis. The aim of this study was to evaluate the union rate of the spinous process and its effect on the clinical results of the procedure.

Methods: All patients were included in the study that underwent a decompressive procedure through spinous process osteotomy be between January 1, 2007 and December 31, 2007. Operation protocols were reviewed. A computed tomography (CT) scan was performed to evaluate the union of the osteotomies of the spinous process. According to the CT-scans, patients were divided into three groups: "complete-union," "partial-union," and "non-union." Patients reported their clinical results through a self-administered questionnaire.

Results: The mean period of follow up was 21.6 months (range, 16-28 months). A total of 44% of the performed osteotomies were considered as united. Ten patients (18%) were classified as "complete-union," 30 patients (55%) as "partial-union," and 15 patients (27%) as "non-union." The "complete-union" group showed better clinical results and scored significantly better in the Oswestry Disability Index and EQ-5D. However, no statistical difference was found in the pain-scores. There were no differences between the "partial-union" group and the "no-union" group.

Conclusions: We found a radiologic union for 60 out of 135 (44%) spinous process osteotomies.

Keywords: Osteotomy; Spinal stenosis.

Fig. 1

Flow chart of patient inclusion to the study, using spinous process osteotomy to facilitate acces to the spinal canal when decompressing the spinal canal in patients suffering from lumbar spinal stenosis. ALS, amyotrophic lateral sclerosis.

Fig. 2

(A) The spinous process ratio (osteotomi-basis coefficient) is calculated from the posterior part of spinous process divided on the basis and the anterior part of the remaining spinous process (a/b). This computed tomography (CT)-scan picture show a spinous process that is not united. (B) This picture show a CT-scan with a united spinous process. The arrow indicates were the osteotomy were performed.

Fig. 3

Self-reported effect of surgery. 0, total improvement; 1, much improvement; 2, some improvement; 3, no improvement; 4, some worse; 5, much worse; 6, worse than ever.