Intradural posterior bony spur causing tethered cord syndrome without split cord malformation: A rare caudal developmental variant

Background: Tethered cord syndrome (TCS) is most commonly associated with congenital spinal dysraphism, thickened filum terminale, lipomas, or split cord malformations (SCM ). Bony causes of tethering are typically described in association with diastematomyelia. Isolated intradural bony spurs without cord splitting or extradural communication are exceptionally rare. Case Description: We report a young adult female presenting with long-standing progressive lower limb sensory disturbances, gait tightness, and urinary dysfunction. A delayed neurological diagnosis resulted in multiple orthopedic procedures for severe foot deformities without prior spinal evaluation. Magnetic resonance imaging revealed a low-lying tethered spinal cord with focal posterior indentation. Surgical exploration demonstrated a solitary posterior intradural bony spur adherent to the inner surface of the dura mater, causing mechanical tethering without SCM or extradural continuity. Complete excision resulted in effective detethering and clinical improvement. Conclusion: This case highlights a rare intradural cause of TCS and emphasizes the importance of early neurological assessment in patients with progressive lower limb deformities. Such isolated intradural bony anomalies may represent focal manifestations within the broader spectrum of caudal developmental disorders.