Wasting of Extensor Digitorum Brevis as a Decisive Preoperative Clinical Indicator of Lumbar Canal Stenosis: A Single‑center Prospective Cohort Study

Abstract

Background: The dilemma in managing patients with low back ache lies in  differentiating radiculopathy from lumbar canal stenosis. This has a huge bearing in patients being planned for surgical intervention as underperforming leads to failed back syndrome whereas over‑doing leads to instability. There still remains a loophole in clinically diagnosing lumbar canal stenosis.

Aim: We opt to utilize a simple bedside clinical examination in routinely assessing patients presenting with low back ache in ruling out underlying canal stenosis.

Subjects and Methods: We performed a prospective study on 120 consecutive  patients presenting with low back ache in the spine clinic. Each of them was neurologically examined and thoroughly assessed for wasting of extensor digitorum brevis (EDB) muscles. These were then correlated with the radio‑imaging and the intraoperative findings.

Results: Lumbar canal stenosis was mostly observed in the age group of 50–60 years. Diagnosis for L3/4 canal stenosis was made in 44/120 (36.6%), L5‑S1 in 52/120 (43.3%), and L3/L4/L5 level in 48/120 (40%) of patients. EDB wasting was seen unilaterally in 72/120 (60%) and bilaterally in 36/120 (30%) of the study group.

Conclusion: This study appraises the clinical implication of observing for the wasting of EDB muscle so as to aid in the diagnosis of lumbar canal stenosis. This simple bedside clinical pearl can help us in predicting the need of further imaging studies and also in taking right therapeutic decision.

Keywords: Extensor digitorum brevis, Lumbar canal, Stenosis