Unilateral calf hypertrophy seen in lumbosacral stenosis: case report and review of the literature.

Study Design: A case report of a patient with neurogenic unilateral calf hypertrophy and review of the literature are reported.

Objectives: To provide further evidence that S1 radiculopathy is predisposed to develop neurogenic muscle hypertrophy.

Summary Of Background Data: Calf hypertrophy, specifically hypertrophy of the gastrocnemius muscle, is a rare but recognized presentation of S1 and less commonly L5 radiculopathies. The pathophysiology of this is incompletely understood.

Methods: We present a 59-year-old patient with painless progressive distal right leg weakness and calf enlargement. Electrodiagnostic studies and MAGNETIC RESONANCE IMAGING scanning were performed to evaluate the extent and cause of radicular damage as the etiology for unilateral calf hypertrophy.

Results: Examination and electrodiagnostic studies revealed right L5, right S1, and left L5 radiculopathies. Imaging studies demonstrated lumbar stenosis at L3-L4, L4-L5, and L5-S1 vertebral levels as well as L4-L5 and L5-S1 foraminal stenosis. After decompressive surgery the progressive nature of the patient's symptomatology halted, and he had partial resolution of his deficits.

Conclusion: Although the patient had bilateral L5 radiculopathies, he only had hypertrophy in the distribution of his right S1 radiculopathy. This supports the hypothesis that dysfunction of the S1 nerve root or its distribution is a predisposing factor to develop neurogenic muscle hypertrophy. Furthermore, patients presenting with unilateral calf hypertrophy need a careful diagnostic evaluation for S1 radiculopathy as well as to exclude asymmetric presentation of systemic neuromuscular conditions.