Split spinal cord malformation in an elderly patient: case report.

Split spinal cord malformations (SCM) typically present in childhood and rarely in adulthood. Very little is known about the SCMs in the elderly, and the diagnosis can be easily missed. A 73-year-old woman with a childhood history of scoliosis and late ambulation milestones presented with a 2-year history of worsening low back pain and progressive difficulty walking. She had a mild gait disturbance with 4/5 weakness in left ankle dorsiflexion. Magnetic resonance imaging revealed a bifid spinal cord contained in a single thecal sac and a tethered cord with low-lying conus at L3. The patient was taken to the operating room and a soft-tissue median septum, as well as all other adhesions, was removed. The filum terminale was identified, coagulated, and divided. Six weeks later, the patient reported decreased back pain, improvement in ambulation, and markedly decreased used of narcotics for her back and leg pain. Her left ankle dorsiflexion strength improved to 4+/5. This patient had two hemicords encased in a single dural tube separated by a nonrigid, fibrous median septum and an associated tethered cord. Adult presentation of SCM is extremely rare. This case highlights the need to consider split cord malformation and tethered cord in the differential diagnosis not only for adults but also the elderly presenting with back pain, scoliosis, and difficulty walking.