Limbus Vertebral Fracture Presenting as Cauda Equina Syndrome Masquerading An Acute Disc Prolapse - A Rare Case Report and Review of Literature

INTRODUCTION: Limbus vertebral fracture is an uncommon injury described in adolescents. It refers to the separation of a bony fragment from the unfused ring apophysis of lumbar vertebral end plate. It usually presents with back pain with/without radiculopathy masquerading an acute disc prolapse. However, the presentation as acute cauda equina syndrome has seldom been reported. CASE REPORT: A 15-year-old male presented to the casualty with a history of acute-onset low back pain and bilateral lower limb radicular pain with weakness, after lifting of a heavy Indian musical instrument (Dholak). This was associated with urinary retention and numbness in perineal region. Examination revealed L5 and S1 weakness with absent ankle jerks bilaterally. Bulbocavernosus reflex was absent. Emergency magnetic resonance imaging imaging was done, which revealed a limbus fracture of cephalad part of L4 vertebral body with displaced fragment into the spinal canal causing compression of the cauda equina. Emergency surgery was done in the form of L3-L4 midline interlaminar microscopic decompression. The patient had complete neurological recovery including the bladder control within 1 month of surgery. The patient had no functional deficits during follow-up at 3 and6 months. Dynamic radiographs taken at the end of 6 months did not show any sign of instability. CONCLUSION: When an adolescent patient with no previous history of backpain presents with acute cauda equina syndrome, a possibility of limbus fracture should also be considered. Early diagnosis and surgical decompression in such cases can bring about complete neurological recovery and excellent clinical outcome.