Clinical Outcome in Lumbar Decompression Surgery for Spinal Canal Stenosis in the Aged Population : A Prospective Swiss Multicenter Cohort Study

The objective of this study was to compare the relative responsiveness of a condition-specific spinal stenosis measure and two generic health status measures for outcome assessment of surgery for degenerative lumbar spinal stenosis, and to examine whether responsiveness statistics and measures of the ability to distinguish clinically important improvement rank the instruments consistently. Physical function and symptom severity scales of the spinal stenosis measure were compared to the Sickness Impact Profile (SIP) and the Roland scale, which is derived from the SIP. Responsiveness was calculated with the standardized response mean, the effect size, and Guyatt's responsiveness statistic. The discriminative ability of the instruments to distinguish patients who improved from those who did not was assessed using satisfaction with surgery as an external criterion. Minimal clinically relevant improvement was estimated using patient satisfaction as the external criterion. All responsiveness statistics revealed the same order of responsiveness; the physical function scale (SRM = 1.07) and symptom severity scales (SRM = 0.96) were more responsive than the Roland scale (SRM = 0.77) which was only slightly more responsive than the SIP (SRM = 0.69). Strikingly, the physical dimension of the SIP (SRM = 0.62) was even less responsive than the global SIP. The shape of and the area under the ROC curves showed that the physical function and symptom severity scales discriminate better between satisfied and unsatisfied patients than the Roland scale and SIP. The sensitivity to detect clinically important changes was somewhat lower at the ends of the scales, especially for the SIP and the Roland scale. Statistical approaches that assess the ability to distinguish clinically important changes and overall responsiveness statistics ranked the measures consistently. On the basis of these findings, we suggest that a condition-specific spinal stenosis measure is preferable as the primary end point in evaluative studies of degenerative lumbar spinal stenosis.

A prospective, observational study. To identify outcome predictors of surgery for degenerative lumbar spinal stenosis. Degenerative lumbar spinal stenosis is the most frequent indication for spine surgery in the elderly. More than 25% of surgical patients have a poor outcome, yet little is known about factors that predict the outcome of surgery. Surgery was performed on 199 patients with degenerative lumbar spinal stenosis, and they were observed for 2 years after surgery in four referral centers. Surgery consisted of decompressive laminectomy with or without arthrodesis. Outcomes included validated measures of symptom severity, walking capacity, and satisfaction with the results of surgery. Potential predictors of outcome included sociodemographic factors and physical examination, as well as radiographic, psychological, social, and clinical history variables. The proportion of patients with severe pain decreased from 81% before surgery to 31% by 2 years afterward. The most powerful preoperation predictor of greater walking capacity, milder symptoms, and greater satisfaction was the patient's report of good or excellent health before surgery. Low cardiovascular comorbidity also predicted a favorable outcome. Patient's assessments of their own health and comorbidity are the most cogent outcome predictors of surgery for spinal stenosis.

The objective of the North American Spine Society (NASS) evidence-based clinical guideline for the diagnosis and treatment of degenerative lumbar spinal stenosis (DLSS) is to provide evidence-based recommendations to address key clinical questions surrounding the diagnosis and treatment of DLSS. The guideline is intended to reflect contemporary treatment concepts for symptomatic DLSS as reflected in the highest quality clinical literature available on this subject as of April 2006. The goals of the guideline recommendations are to assist in delivering optimum, efficacious treatment, and functional recovery from this spinal disorder. To provide an evidence-based tool that assists practitioners in improving the quality and efficiency of care delivered to patients with DLSS. Evidence-based clinical guideline. This report is from the Spinal Stenosis Work Group of the NASS Clinical Guidelines Committee. The work group comprised medical, diagnostic, interventional, and surgical spinal care specialists, all of whom were trained in the principles of evidence-based analysis. In the development of this guideline, the work group arrived at a consensus definition of a working diagnosis of lumbar spinal stenosis by use of a modification of the nominal group technique. Each member of the group formatted a series of clinical questions to be addressed by the group and the final list of questions agreed on by the group is the subject of this report. A literature search addressing each question and using a specific literature search protocol was performed on English language references found in MEDLINE, EMBASE (Drugs and Pharmacology), and four additional, evidence-based, databases. The relevant literature to answer each clinical question was then independently rated by at least two reviewers using the NASS-adopted standardized levels of evidence. An evidentiary table was created for each of the questions. Any discrepancies in evidence levels among the initial raters were resolved by at least two additional members' review of the reference and independent rating. Final grades of recommendation for the answer to each clinical question were arrived at in face-to-face meetings among members of the work group using the NASS-adopted standardized grades of recommendation. When Levels I to IV evidence was insufficient to support a recommendation to answer a specific clinical question, expert consensus was arrived at by the work group through the modified nominal group technique and is clearly identified as such in the guideline. Eighteen clinical questions were asked, addressing issues of prognosis, diagnosis, and treatment of DLSS. The answers to these 18 clinical questions are summarized in this document along with their respective levels of evidence and grades of recommendation in support of these answers. A clinical guideline for DLSS has been created using the techniques of evidence-based medicine and using the best available evidence as a tool to aid both practitioners and patients involved with the care of this disease. The entire guideline document including the evidentiary tables, suggestions for future research, and all references is available electronically at the NASS Web site (www.spine.org) and will remain updated on a timely schedule.