Lumbar Superior Articular Process-Pedicle Impingement, a Previously Unrecognized Pathological Cause of Low Back Pain: A Case Report.

Abstract

Superior articular process-pedicle impingement may be an underrecognized mechanical pain generator in posture-dependent axial low back pain. We report a case of a 32-year-old male professional football player who presented with low back pain that was provoked by forward flexion and right lateral bending and was refractory to conservative measures. Radiographs and computed tomography scans showed near-elimination of the osseous interval between the right S1 superior articular process and the caudal aspect of the right L5 pedicle, with reactive cortical change. Targeted infiltration of local anesthetic at the suspected impingement interface produced immediate pain relief, and facet-preserving full-endoscopic bony decompression led to sustained improvement at 3 months. We propose that superior articular process-pedicle impingement should be considered in patients presenting with posture-dependent axial low back pain. The following 3 features serve as a practical diagnostic triad: concordant provocation; radiographic or computed tomographic evidence of superior articular process-pedicle contact or near-contact; and an immediate response to targeted local anesthesia. Facet-preserving full-endoscopic decompression is a reasonable option for refractory cases.