IPD without bony decompression versus conventional surgical decompression for lumbar spinal stenosis: 2-year results of a double-blind randomized controlled trial.

PURPOSE: Interspinous process devices (IPDs) are implanted to treat patients with intermittent neurogenic claudication (INC) based on lumbar spinal stenosis. It is hypothesized that patients with lumbar spinal stenosis treated with IPD have a faster short-term recovery, an equal outcome after 2 years and less back pain compared with bony decompression. METHODS: A randomized design with variable block sizes was used, with allocations stratified according to center. Allocations were stored in prepared opaque, coded and sealed envelopes, and patients and research nurses were blind throughout the follow-up. Five neurosurgical centers (including one academic and four secondary level care centers) included participants. 211 participants were referred to the Leiden-The Hague Spine Prognostic Study Group. 159 participants with INC based on lumbar spinal stenosis at one or two levels with an indication for surgery were randomized into two groups. Patients and research nurses were blinded for the allocated treatment throughout the study period. 80 participants received an IPD and 79 participants underwent spinal bony decompression. The primary outcome at long-term (2-year) follow-up was the score for the Zurich Claudication Questionnaire. Repeated measurement analyses were applied to compare outcomes over time. RESULTS: At two years, the success rate according to the Zurich Claudication Questionnaire for the IPD group [69 % (95 % CI 57-78 %)] did not show a significant difference compared with standard bony decompression [60 % (95 % CI 48-71 %) p value 0.2]. Reoperations, because of absence of recovery, were indicated and performed in 23 cases (33 %) of the IPD group versus 6 (8 %) patients of the bony decompression group (p < 0.01). Furthermore, long-term VAS back pain was significantly higher [36 mm on a 100 mm scale (95 % CI 24-48)] in the IPD group compared to the bony decompression group [28 mm (95 % CI 23-34) p value 0.04]. CONCLUSIONS: This double-blinded study could not confirm the advantage of IPD without bony decompression over conventional 'simple' decompression, two years after surgery. Moreover, in the IPD treatment arm, the reoperation rate was higher and back pain was even slightly more intense compared to the decompression treatment arm.

Failed back (surgery) syndrome: time for a paradigm shift.

1. The group of patients with so-called 'failed back surgery syndrome' (FBSS) is very diverse. Published studies evaluating the outcome of surgical treatment vary widely in terms of surgical interventions that were performed. Results from these papers cannot be generally applied to all people who have persisting complaints after low back surgery. 2. The literature search that was performed demonstrated that the articles that scored as acceptable on assessment bias demonstrated a low to moderate patient-perceived recovery percentage. The only randomized controlled trial on this topic did not demonstrate a difference between instrumented fusion and cognitive intervention and exercise. 3. Current research does not show repeat surgery to be successful in 'FBSS patients', but clinical practice indicates that, in a small, carefully selected group, repeat surgery can yield rewarding results. However, parameters that make a patient prone to recover from a subsequent surgical intervention cannot be found in the literature. 4. The term 'failed back surgery syndrome' implies a causative role of surgery in a problem situation; failed back surgery syndrome is frequently regarded as failed back surgery. The literature does not, however, provide evidence for this. 5. It is important to inform the patient adequately to shape realistic expectations. Preoperative evaluation of parameters evaluating the psychological condition could help to better predict the outcome of surgery. 6. The term 'failed back surgery syndrome' has been demonstrated to be an ill-defined term, serving as a container for all kinds of back and leg problems, and wrongly implying a definite role for the surgical intervention in the aetiology. We suggest shifting the paradigm to 'failed back syndrome'. With this term we suggest defining those patients with back and radicular leg pain without a structural deficit, or with a structural deficit that has a low a priori chance of benefiting from a surgical intervention.