Year : 2010 LumbSten : the lumbar spinal stenosis outcome study

Background: Lumbar spinal stenosis is the most frequent reason for spinal surgery in elderly people. For patients with moderate or severe symptoms different conservative and surgical treatment modalities are recommended, but knowledge about the effectiveness, in particular of the conservative treatments, is scarce. There is some evidence that surgery improves outcome in about two thirds of the patients. The aims of this study are to derive and validate a prognostic prediction aid to estimate the probability of clinically relevant improvement after surgery and to gain more knowledge about the future course of patients treated by conservative treatment modalities. Methods/Design: This is a prospective, multi-centre cohort study within four hospitals of Zurich, Switzerland. We will enroll patients with neurogenic claudication and lumbar spinal stenosis verified by Computer Tomography or Magnetic Resonance Imaging. Participating in the study will have no influence on treatment modality. Clinical data, including relevant prognostic data, will be collected at baseline and the Swiss Spinal Stenosis Questionnaire will be used to quantify severity of symptoms, physical function characteristics, and patient’s satisfaction after treatment (primary outcome). Data on outcome will be collected 6 weeks, and 6, 12, 24 and 36 months after inclusion in the study. Applying multivariable statistical methods, a prediction rule to estimate the course after surgery will be derived. Discussion: The ultimate goal of the study is to facilitate optimal, knowledge based and individualized treatment recommendations for patients with symptomatic lumbar spinal stenosis. Background Pain radiating to lower extremities is a frequent complaint, especially in elderly people, and lumbar spinal stenosis is one of the underlying conditions. Lumbar spinal stenosis is defined as “buttock or lower extremity pain, which may occur with or without low back pain, associated with diminished space available for the neural and vascular elements in the lumbar spine”[1]. Narrowing can be localized at three different anatomic structures, the central canal, the lateral recess, or the neural foramina. Patients complain of neurogenic claudication (pain in the buttocks and lower extremities with or without low back pain provoked by walking or extended standing and relieved by rest and bending forward) that is compatible with a narrowing of the lumbar spinal canal. In some patients Computer Tomography (CT) or Magnetic Resonance Imaging (MRI) can verify a stenosis in the lumbar spinal region, in others not. Vice versa a remarkable proportion of asymptomatic persons older 60 years show substantial narrowing of the spinal canal [2]. The incidence and prevalence of symptomatic lumbar stenosis are unknown. It is estimated from data in the USA that every year 90 out of 100.000 persons older than 60 years undergo lumbar surgery and lumbar spinal stenosis is the most frequent indication for this procedure [3,4]. In the Canton of Zurich with 1.3 Mio (2008) inhabitants we estimate that more than 300 operations on patients with lumbar spinal stenosis are performed every year. * Correspondence: johann.steurer@usz.ch Horten Centre for patient oriented research and knowledge transfer, University of Zurich, University Hospital, 8091 Zurich, Switzerland Full list of author information is available at the end of the article Steurer et al. BMC Musculoskeletal Disorders 2010, 11:254 http://www.biomedcentral. com/1471-2474/11/254 © 2010 Steurer et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Treatment modalities The natural course of spinal stenosis can vary, but is in most patients a relatively stable disorder, with severe disability and neurological deficits developing over time and not rapidly. In the SPORT trial it was reported that in most patients treated conservatively, symptoms did not worsen over four years [5]. A further trial focusing on development of pain over a five year period showed that in 70% of patients pain reached a plateau, in 15% pain increased over time and in 15% pain disappeared spontaneously [6,7]. For patients with moderate or severe symptoms different conservative and surgical treatment modalities are recommended, but knowledge about the effectiveness of these measures is scarce. Most of the studies evaluating non-operative treatments are of low quality and there is a lack of knowledge about the appropriate treatment of these patients [1,8]. There is little evidence that pharmacological treatment, including non-steroidal analgesics, calcitonin, methylcobalamin or intravenous lipoprostaglandin E, provides long-term benefit in patients with lumbar spinal stenosis [1]. A systematic review of the literature yielded insufficient evidence to draw conclusions regarding the effectiveness of physical therapy for lumbar spinal stenosis. In certain subgroups of patients physical therapy and exercise may be beneficial in controlling symptoms of neurogenic claudication in lumbar spinal stenosis, but the evidence that spinal manipulation offers benefit in the treatment is insufficient [1,8]. Epidural injections may have potential benefit and may be tried before surgery, but results about efficiency are mixed [9-13]. Some data suggest that epidural injection of corticosteroids relieves leg pain for a limited time but has no effect on the functional status or the need for surgery after one year [14]. The authors of a systematic review came to the conclusion that evidence is insufficient to recommend epidural injections in patients with spinal stenosis [15]. There is some evidence from randomized trials [5,16,17] and observational studies [18-22] that surgery improves symptoms in patients with spinal stenosis. The therapeutic effectiveness of conservative measures or surgery, as mentioned in the guidelines of the North American Spine Society, should be evaluated by further randomised controlled trials [1]. Such trials, however, as demonstrated in the study by Weinstein [16], are difficult to execute in patients with spinal stenosis. In the aforementioned study, patients with spinal stenosis were randomly allocated to either surgery or conservative treatment. Two years after randomization, only 67% of patients in the surgical group actually received surgery and 43% of those who were assigned to conservative treatment had also undergone surgery. Physicians and/ or patients seem to have strong preferences for surgery or conservative therapy impeding the accomplishment of randomised trials [23]. The long term success rates of surgery vary between 45% and 72%, depending on the measured clinical outcome assessed (pain, walking capacity, neurologic symptoms, working ability) [24]. The outcome of surgery depends on a number of different factors. Indicators of postoperative outcome have been evaluated in different populations and the results have been summarized in a systematic review [25,26]. A lower self rated preoperative health-status, comorbidity, depression and limited, preoperative walking ability are strong predictors of an unfavorable clinical outcome.