Surgery for lumbar spinal stenosis. Attempted meta-analysis of the literature.
Purpose of Study
This paper published by Turner et al in 1992 represented an attempted meta-analysis of the literature covering a 24 year period (1996-1990). Based on the methods described by the authors, 74 studies met the inclusion criteria. One of the major issues in trying to include or exclude studies was a lack of a standardized outcome measure. While many outcome instruments have been developed and validated since 1992, this is still an area that presents a weakness in some modern day research. For the purposes of this meta-analysis, the authors developed their own criteria for good-to-excellent, fair, and poor outcomes. This type of outcome classification was common amongst published papers for the time periods covered.
Out of the 74 studies included, there were no randomized trials. A large majority of the studies were retrospective in nature. It is our opinion that Turner et al did present some interesting data but more importantly, shed some valuable conclusions related to directions for further study. The authors clearly stated that the biggest finding was that the quality of scientific literature reviewed was poor. This related to study design, methodologic flaws, and as discussed, a lack of objective measures.
In their discussion, Turner et al did make the recommendation that future studies use outcome measures that are rated by the patient, instead of the surgeon. Furthermore, details of the patients pre-operative clinical symptoms and specifics of surgical intervention (levels involved) is another area that was lacking in the literature in the 1970-1990’s and continues to improve in modern day research.
Despite lumbar spinal stenosis being one of the most diagnosed degenerative disorders especially in older adults, we still lack knowledge regarding the epidemiology of this condition. We have come a long way with the development of disease-specific outcome measures for spinal stenosis, but a consensus on specific treatments, including surgery is still lacking. The North American Spine Society (NASS) developed evidenced based guidelines for lumbar spinal stenosis in 2007 and has since updated them as a means of assisting spinal practitioners with improving quality and efficacy of care. In looking at the guidelines that relate specifically to surgical management of spinal stenosis, some solid grades of recommendations have been made for specific subsets of patients with lumbar spinal stenosis, but in many regards we are still limited in using data from published studies that have methodologic flaws, differing outcome measures, and other short comings that limit therapeutic evidence.
Nearly 24 years after this publication by Turner et al, the scientific literature has grown tremendously and overcome many of the short-comings of the previous decades. While disease classification systems, methods of diagnosing, treatment options, and outcome measurement have all improved in many regards, the opinions drawn by Turner et al in recommending the adoption of more objectivity and rigorous standards for both investigators and editors, is perhaps even more valid today and should remain a priority.