THE MID- TO LONG-TERM NATURAL HISTORY OF DEGENERATIVE LUMBAR SPINAL STENOSIS AND PREDICTORS FOR CLINICAL DETERIORATION

Abstract

<p>THE MID- TO LONG-TERM NATURAL HISTORY OF DEGENERATIVE LUMBAR SPINAL STENOSIS AND PREDICTORS FOR CLINICAL DETERIORATION</p><p><br></p><p>SAMUEL YAN-LIK NG¹, JANUS SIU-HIM WONG¹, WANG GUODONG¹, LONG HEI HA¹, JASON PUI-YIN CHEUNG¹, <u>GRAHAM KA-HON SHEA</u>¹</p><p><br></p><p><em>¹DEPARTMENT OF ORTHOPAEDICS AND TRAUMATOLOGY, THE UNIVERSITY OF HONG KONG</em></p><p><br></p><table><tbody><tr><td><p><strong>Background: </strong>Mid- to long-term data on the natural history of degenerative lumbar spinal stenosis (LSS) remains limited as surgery is increasingly favoured. We sought to characterize this in a patient cohort with regular follow-up. </p><p><br></p><p><strong>Objective: </strong>To characterize the natural history of LSS and prevalence of clinical deterioration, as well as to identify risk and protective factors.</p><p><br></p><p><strong>Methodology: </strong>We identified 202 patients with symptomatic LSS and a follow-up period ≥ 5 years. Clinical deterioration was defined as ≥ 1 of myotomal lower limb weakness, sphincter disturbance, or decrease in walking tolerance to ≤10 minutes due to neurogenic claudication. Radiological assessment was performed upon standing lumbar X-rays and lumbosacral MRIs obtained after symptom onset. Univariate analysis was performed, with variables demonstrating significance levels of p < 0.1 included in subsequent multivariable logistic regression analysis. Receiver Operator Characteristic (ROC) curves and Kaplan Meier survival curves were plotted for statistically significant risk factors.</p><p><br></p><p><strong>Results: </strong>Age at onset of neurological symptoms was 65.2 ± 4.2 years and mean follow-up duration was 121 ± 40.0 months. Clinical deterioration occurred in 39/202 (19.3%) patients. Amongst those with deterioration, 36 (92.3%) reported reduced walking tolerance due to neurogenic claudication, 8 (20.5%) exhibited myotomal weakness, and 2 (5.1%) developed sphincter disturbance. Presence of lumbar developmental spinal stenosis was a risk factor for deterioration (p = 0.043) whilst increased dural sac area (DSA) was protective (p = 0.003), and these remained significant on multivariate logistic regression with adjusted hazards ratios of 10.11 and 0.98 respectively. DSA ≤ 55 mm² exhibited an AUC of 0.781 in predicting clinical deterioration within 5 years of symptom onset.</p><p><br></p><p><strong>Conclusion: </strong>Conservative treatment of LSS is a reasonable management option especially in patients with low ambulatory expectations, favourable dural sac area, and an absence of developmental spinal stenosis.</p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p></td></tr></tbody></table><p><br></p>