Outcomes and their predictors in lumbar spinal stenosis: a 12-year follow-up.

PURPOSE: The aim of this prospective observational cohort study was to evaluate long-term outcomes in patients with mild-to-moderate lumbar spinal stenosis (LSS) and to analyse the predictors of clinical outcomes. METHODS: A group of 53 patients were re-examined after a median period of 139 months. Evaluations were made of subjective clinical outcome, objective clinical outcome and its predictors, any correlation between subjective and objective outcome, and the development of changes in radiological and electrophysiological parameters after 12 years. RESULTS: Satisfactory objective and subjective clinical outcomes were recorded in 54.7 and 43.4% of patients, respectively. No statistically significant correlation between objective and subjective clinical outcome was found (Spearman coefficient = 0.225, p = 0.132). Patients with isolated unsatisfactory subjective outcome exhibited the highest Functional Comorbidity Index of all subgroups. Electrophysiological and radiological findings did not demonstrate statistically significant changes after 12-year follow-up. Multivariate logistic regression confirmed only the lowest transverse diameter of spinal canal ≦13.6 mm as an independent predictor of unsatisfactory clinical outcome (OR = 5.51). CONCLUSIONS: Satisfactory objective and subjective clinical outcomes were disclosed in about half of the patients with mild-to-moderate LSS in a 12-year follow-up. The number of comorbid diseases had an unfavourable effect on subjective evaluation of clinical outcome. The lowest transverse diameter of spinal canal proved to be the only independent predictor of deterioration of clinical status in LSS patients.

Neurological impairment score in lumbar spinal stenosis.

BACKGROUND AND AIM: The Oswestry Disability Index (ODI) is an interview-based instrument generally accepted as a measure of disability in patients with lumbar spinal stenosis (LSS). There is, however, no generally accepted measure for neurological impairment in LSS. We therefore developed a scoring system [neurological impairment score in lumbar spinal stenosis (NIS-LSS)] for the assessment of neurological impairment in the lower limbs of patients with LSS, then performed a validation study to facilitate its implementation in the routine clinical evaluation of patients with LSS. METHODS: The NIS-LSS is based on the combined evaluation of tendon reflexes, tactile and vibratory sensation, pareses, and the ability to walk and run; the total score ranges from 0 (inability to walk) to 33 points (no impairment). A group of 117 patients with LSS and a control group of 63 age- and sex-matched healthy volunteers were assessed with the NIS-LSS to evaluate capacity to discriminate between LSS patients and controls. A correlation with the ODI was performed for assessment of construct validity. RESULTS: The median NIS-LSS was 27 points in LSS patients compared with 33 points in controls. The NIS-LSS discriminated LSS patients from healthy controls to a high degree of significance: the optimum NIS-LSS cut-off value was 32 points with a sensitivity of 85.5% and a specificity of 81.3% (p < 0.001). Overall NIS-LSS correlated significantly with the ODI score (p < 0.001). Vibratory sensation (p = 0.04), presence of paresis (p = 0.01) and especially the ability to walk and run (p < 0.001) were the NIS-LSS elements that correlated most closely with the degree of disability assessed by the ODI. CONCLUSIONS: The NIS-LSS is a simple and valid measure of neurological impairment in the lower limbs of patients with LSS (without comorbidity), discriminating them from healthy controls to a high degree of sensitivity and specificity and correlating closely with the degree of disability. It extends our ability to quantify neurological status and to follow changes arising out of the natural course of the disease or the effects of treatment.

Prediction of long-term clinical outcome in patients with lumbar spinal stenosis.

PURPOSE: The natural course of lumbar spinal stenosis (LSS) fluctuates and is not necessarily progressive. The aim of this study was to explore the predictors of clinical outcome in patients with LSS that might eventually help to optimise the therapeutic choices. METHODS: A group of 56 patients (27 men, 29 women, median age 55; range 31-72 years) with clinically symptomatic mild-to-moderate LSS were re-examined after a median period of 88 months and their clinical outcomes classified as satisfactory (34 patients, 60.7 % with stable or improved clinical status) or unsatisfactory (22 patients, 39.3 % for whom clinical status deteriorated). A wide range of demographical, clinical, imaging and electrophysiological entry parameters were evaluated as possible predictors of clinical outcome. RESULTS: Unlike the demographical, clinical and imaging variables, certain electrophysiological parameters were significantly associated with unsatisfactory outcomes. There was a significantly higher prevalence of pluriradicular involvement detected by EMG in patients with unsatisfactory outcome than those with satisfactory outcome (68.2 vs. 32.3 %; p = 0.035). Patients with unsatisfactory outcome had more frequent bilateral abnormalities of the soleus H-reflex (50.0 vs. 14.7 %; p = 0.015) and lower mean H-reflex amplitude. Multivariate logistic regression proposed two variables as mutually independent predictors of unsatisfactory outcome: EMG signs of pluriradicular involvement (OR = 3.72) and averaged soleus H-reflex amplitude ≤ 2.8 mV (OR = 2.87). CONCLUSIONS: Satisfactory outcomes were disclosed in about 61 % of the patients with mild-to-moderate LSS in a 7-year follow-up. Electrophysiological abnormalities, namely the presence of pluriradicular involvement and abnormalities of the soleus H-reflex, were predictive of deterioration of clinical status in these patients.

Dynamic electrophysiological examination in patients with lumbar spinal stenosis: is it useful in clinical practice?

UNLABELLED: Neurogenic claudication (NC) is typical of lumbar spinal stenosis (LSS). One suspected pathophysiological mechanism underlying NC is intermittent hypoxia of cauda equina fibres resulting from venous pooling, which may lead to ischaemic nerve conduction failure and to transient clinical and electrophysiological changes after exercise. The aim of this study was to evaluate the appearance of significant transient electrophysiological abnormalities after walking exercise in patients with LSS and to establish the contribution of dynamic electrophysiological examination in the differential diagnostics of patients with LSS. The study participants were 36 consecutive patients with LSS demonstrated by computed tomography (CT). The control groups included, respectively, 28 patients with diabetes mellitus and clinically manifested polyneuropathy, and 32 healthy volunteers. The LSS patients were divided into four subgroups based on the clinical severity of the disease (with respect to the presence or absence of NC in the history and pareses on neurological examination). Soleus H-reflex, tibial F-wave and motor evoked potentials (MEPs) to abductor hallucis muscle were examined in all groups, before and after quantified walking on a treadmill. The electrophysiological parameters measured after an exercise treadmill test (ETT) in LSS patients and in both control groups were compared with the same parameters obtained before ETT. The study shows that the electrophysiological parameters reveal minimal but statistically significant changes after walk loading in patients with LSS (a prolongation of the minimal latency of the tibial F-wave and of the latency of the soleus H-reflex). The changes in these parameters were demonstrated not only in patients with NC but also in patients without NC. More pronounced changes were found in LSS patients exhibiting chronic lower extremity pareses. CONCLUSIONS: From among a large battery of electrophysiological tests, only the minimal latency of the tibial F-wave and the latency of the soleus H-reflex exhibit changes after walk loading in patients with LSS. These are minimal but statistically significant. Dynamic electrophysiological examination can illustrate the pathophysiology of NC in LSS, but from a practical point of view its contribution to the differential diagnostics of LSS or diabetic polyneuropathy is limited by an absence of established cut-off values.

Differential diagnostics in patients with mild lumbar spinal stenosis: the contributions and limits of various tests.

Lumbar spinal stenosis (LSS) and diabetic polyneuropathy are common ailments of older age. Many people suffer from both at the same time. In such patients it may sometimes be difficult to separate signs and symptoms that could be attributed to either disease. This study evaluates the contributions and limits of various tests, especially the exercise treadmill test (ETT) and electrophysiological examination, in the diagnostics of patients with mild LSS. Twenty-nine patients with mild LSS documented by computed tomography (CT) participated in this study. Sixteen of the patients had neurogenic claudication (LSS NC+), and 13 patients did not (LSS NC-). Patients with LSS were compared with a group of 24 patients with diabetic polyneuropathy and 25 healthy volunteers. The distance covered, the time spent walking and the reasons for preliminary termination of the ETT were evaluated in all groups. Initial electrophysiological examination included electromyography (EMG) from the upper and lower extremities and motor evoked potentials (MEPs) to the lower extremities. LSS NC+ patients covered a significantly shorter distance and the time spent walking was significantly shorter than in LSS NC- patients and in the two control groups. The main reason for preliminary termination of the ETT was the development of NC in 67% of the LSS NC+ patients. In contrast, no LSS NC- patient and none from the control groups revealed NC, but 31% of LSS NC- patients were not able to finish the ETT for other reasons (e.g. dyspnoea). Electrophysiological parameters evaluated from the upper extremities distinguished diabetic patients from LSS patients. The latencies of the tibial F-wave, soleus H-reflex and spinal MEP response reliably distinguished healthy volunteers from diabetic patients and LSS patients, and particularly LSS patients from diabetic patients. The chronodispersion of the tibial F-wave distinguished LSS NC+ patients from the other groups. The results of the study show that electrophysiological examination contributes to the differential diagnostics between mild lumbar spinal stenosis and diabetic polyneuropathy. The contribution of electrophysiological methods in verification of NC in LSS patients is limited (chronodispersion of the tibial F-wave only). The ETT is useful in confirmation of NC and walking capacity verification, but restriction of walking capacity should be carefully analysed.

Conservative treatment versus surgery in spondylotic cervical myelopathy: a prospective randomised study.

A prospective randomised 2-year study was performed to compare the conservative and operative treatment of mild and moderate forms of spondylotic cervical myelopathy (SCM). Forty-eight patients presenting with the clinical syndrome of SCM, with a modified Japanese Orthopaedic Association (mJOA) score of 12 points or more, were randomised into two groups. Group A, treated conservatively, consisted of 27 patients, mean age 55.6 +/- 8.6 years, while group B was treated surgically (21 patients, mean age 52.7 +/- 8.1 years). The clinical outcome was measured by the mJOA score, recovery rate (RR), timed 10 m walk, score of daily activities (recorded by video and evaluated by two observers blinded to the therapy), and by the subjective assessment of the patients at 6, 12, and 24 months of the follow-up. There was, on average, no significant deterioration in mJOA score, recovery ratio, or timed 10 m walk within either group during the 2 years of follow-up. In the surgery group there was a slight decline in the scores for daily activities and subjective evaluation. A comparison of the two groups showed no significant differences in changes over time in mJOA score or quantified gait, but there were significant differences in the score of daily activities recorded by video at 24 months, which was a little lower in the surgical group, and also in RR and subjective evaluation, which were both worse in the surgical group at months 12 and 24. However, at month 6, this last parameter was significantly better in the surgical than in conservative group. Surgical treatment of mild and moderate forms of SCM in the present study design, comprising the patients with no or very slow, insidious progression and a relatively long duration of symptoms, did not show better results than conservative treatment over the 2-year follow-up.