Do patients with lumbar spinal stenosis benefit from decompression of levels with adjacent moderate stenosis? A prospective cohort study from the NORDSTEN study.

BACKGROUND: Lumbar spinal stenosis (LSS) is characterized by pain that radiates to the buttocks and/or legs, aggravated by walking and relieved by forward flexion. There is poor correlation between clinical symptoms and severity of stenosis on MRI, and multilevel stenosis has not been described to present worse symptoms or treatment outcomes, compared with patients with single-level stenosis. In patients with one level with severe stenosis combined with an adjacent level with moderate stenosis, the surgeon must decide whether to decompress only the narrowest level or both, to achieve the best possible outcome. The potential benefits of performing surgery on an adjacent moderate stenosis is debated, and the scientific evidence in scarce. PURPOSE: The aim of the present study was to investigate whether patients with a level of adjacent moderate stenosis, along with an index stenosis, benefitted from a dual-level decompression (DLD) compared with a single-level decompression (SLD). Furthermore, to investigate whether DLD patients had longer duration of surgery and hospital stay, higher rates of complications and/or lower rate of reoperations compared with SLD patients. STUDY DESIGN: Prospective cohort study. PATIENT SAMPLE: We analyzed data from the Norwegian Degenerative Spondylisthesis and Spinal Stenosis study- Spinal Stenosis Trial (NORDSTEN-SST). In this randomized multicenter study, 437 patients were included, evaluating clinical outcomes of three different surgical treatment options for LSS. Patients with degenerative spondylolisthesis were excluded. METHOD: Based on preoperative MRI, the present analysis included all patients who had a moderate stenosis (defined as Schizas B or C) in addition to a predefined index stenosis (the level with the smallest cross-sectional area). We compared patients who, based on the surgeons` choice, received a dual-level decompression, with those receiving a single-level decompression. OUTCOME MEASURES: The primary outcome was mean change in the Oswestry Disability Index (ODI) score from baseline to 2-year follow up. Secondary outcomes were proportion of success (30% reduction in ODI score), the Numeric Rating Scales for back and leg pain (NRS), the EuroQol 5-dimensional questionnaire utility index (EQ-5D), the Zurich Claudication Questionnaire (ZCQ), the Global Perceived Effect (GPE)-scale, duration of surgery, duration of hospital stay, perioperative complications and reoperation rates. RESULTS: Among the 222 patients, included in the analysis, 108 underwent DLD and 114 underwent SLD. There was no difference in change scores for any of the investigated patient-reported outcomes between the groups after 2 years. However, the DLD group had longer duration of surgery and longer length of hospital stay. There was no difference in reoperation rates or perioperative complications. CONCLUSION: This study, alongside the NORDSTEN-LSS trial on patients with adjacent moderate stenosis as well as an index stenosis, showed no superior clinical effectiveness for dual-level surgery compared with single-level surgery.

Comparable increases in dural sac area after three different posterior decompression techniques for lumbar spinal stenosis: radiological results from a randomized controlled trial in the NORDSTEN study.

PURPOSE: To investigate changes in dural sac area after three different posterior decompression techniques in patients undergoing surgery for lumbar spinal stenosis. Decompression of the nerve roots is the main surgical treatment for lumbar spinal stenosis. The aim of this study was to radiologically investigate three commonly used posterior decompression techniques. METHODS: The present study reports data from one of two multicenter randomized trials included in the NORDSTEN study. In the present trial, involving 437 patients undergoing surgery, we report radiological results after three different midline retaining posterior decompression techniques: unilateral laminotomy with crossover (UL) (n = 146), bilateral laminotomy (BL) (n = 142) and spinous process osteotomy (SPO) (n = 149). MRI was performed before and three months after surgery. The increase in dural sac area and Schizas grade at the most stenotic level was evaluated. Three different predefined surgical indicators of substantial decompression were used: (1) postoperative dural sac area of > 100 mm2, (2) increase in the dural sac area of at least 50% and (3) postoperative Schizas grade A or B. RESULTS: No differences between the three surgical groups were found in the mean increase in dural sac area. Mean values were 66.0 (SD 41.5) mm2 in the UL-group, 71.9 (SD 37.1) mm2 in the BL-group and 68.1 (SD 41.0) mm2 in the SPO-group (p = 0.49). No differences in the three predefined surgical outcomes between the three groups were found. CONCLUSION: For patients with lumbar spinal stenosis, the three different surgical techniques provided the same increase in dural sac area. CLINICAL TRIAL REGISTRATION: The study is registered at ClinicalTrials.gov reference on November 22th 2013 under the identifier NCT02007083.