Sarcopenia and Interlaminar Epidural Steroid Injection Outcomes in Lumbar Spinal Stenosis

Inclusion Criteria: * Clinical and radiological diagnosis of lumbar spinal stenosis * Persistent symptoms despite conservative treatment and scheduled to undergo interlaminar epidural steroid injection as part of routine clinical care * Age between 50 and 75 years * Low back and/or leg pain for at least 3 months * Availability of lumbar magnetic resonance imaging (MRI) Exclusion Criteria: * History of lumbar fusion surgery * Lumbar epidural steroid injection within the previous 3 months * Prominent radiculopathy due to lumbar disc herniation * Severe motor deficit or an indication for surgical treatment * Polyneuropathy, neuromuscular disease, or neurological disease that may significantly affect muscle mass * Active malignancy or systemic inflammatory disease * Significant mobility limitation due to advanced hip or knee osteoarthritis * Cognitive impairment or communication problems that may prevent completion of study assessments * Coagulopathy or active infection constituting a contraindication to epidural injection * Inflammatory rheumatic disease requiring chronic corticosteroid therapy