A Rare Presentation: Cauda Equina Compression Secondary to an L1 Burst Fracture in Osteoporosis

Cauda equina syndrome (CES) rarely occurs in upper lumbar spinal pathologies above L2. Osteoporosis is a consideration in determining the operative approach. We report a case of CES as a result of an L1 burst fracture in an osteoporotic lady with schizophrenia. A 74-year-old schizophrenic lady presented with traumatic lower back pain with no neurological deficit. Due to her psychiatric condition, the clinical assessment was challenging. On day 3 of admission, there was an acute total loss of motor function over bilateral L2-L3 myotomes to MRC grade 0/5, progressively involving bilateral L2-S1 myotomes symmetrically. There was associated symmetrical bilateral lower limb hypotonia, areflexia, acute urinary retention, and absence of anal tone and bulbocavernosus reflex. Magnetic resonance imaging (MRI) reported a severe L1 compression fracture with retropulsion and cauda equina compression. Conus medullaris terminated at T12. An L1 anterior corpectomy and decompression with T11-L3 posterior instrumentation and stabilization were performed. Intraoperatively noted osteoporotic bone. Postoperatively, motor function improved to MRC grade 4/5 over bilateral L4-S1 myotomes by postoperative day 15 with rehabilitation. A variant in anatomy may result in a high differentiation of the conus medullaris into the cauda equina. Thus, an L1 burst fracture may, on rare occasions, result in CES instead of conus medullaris syndrome. Special attention needs to be given to psychiatric patients who are unable to provide a good history and comply with a physical examination. MRI remains the diagnostic gold standard for CES. Early diagnosis and early surgical decompression are recommended for maximum functional recovery. Osteoporosis further complicates the operative intervention as both the anterior and posterior approaches must be adapted for better stabilization and surgical outcome. Early initiation of rehabilitation is crucial for postoperative functional recovery.