Diastematomyelia Presenting in Adulthood as Back Pain

Abstract

A 27-yr-old woman presented with a 4-yr history of postpartum low back pain and 1 yr of vague leg dysesthesias. Her pain had limited both function and ambulation, and she complained of increasing urinary tract infections, urgency, and constipation. Her other medical conditions included spina bifida occulta, congenital scoliosis, childhood thoracic fusion, high-arched feet, unicorn uterus, and solitary kidney, ovary, and fallopian tube. She demonstrated lumbar midline hypertrichosis and thoracic levoscoliosis. Her bilateral lower limb strength was 5/5 with asymmetric high-arched feet. Reflexes were 3+ on right and 2+ on left patella and 2+ at bilateral achilles tendons. Her sensation to light touch and temperature was intact, and her gait pattern was normal. Plain x-rays showed bifid L3 and L4. Noncontrast magnetic resonance imaging demonstrated an L2–L5 spinal dysraphism and split spinal cord (Fig. 1) rejoining at L3 with tethering into fatty filum terminale. She underwent tethered cord release and laminectomy.FIGURE 1: Magnetic resonance lumbar spine axial T2 fat suppression image showing split cord (arrow).On 1-mo surgical follow-up, her “sharp” lumbar back pain near the surgical site persisted with bilateral thigh/knee numbness and urinary incontinence; she ambulated with a walker. Examination showed diminished sensation to light touch at her quadriceps and hamstrings, intact pinprick sensation, reflexes 2+/4, and no focal weakness. Diastematomyelia is a dysraphism with an osseous, cartilaginous, or fibrous septum bifurcating the spinal cord.1 Spinal cord malformations often associate with other cord/column anomalies, including tethered cord syndrome and scoliosis.1 Tethered cord syndrome is a stretch-induced disorder with caudal anchoring by an inelastic structure.2 Adult presentation is uncommon and can be misdiagnosed as lumbar degenerative disease because of subtle, nonspecific findings. The degree of cord traction, not the tethering level or origin, is critical. Typically, patients present with pain, weakness, and urologic dysfunction.2 Acute symptoms may follow lumbar spinal trauma (pregnancy, childbirth, exercise, etc.) with filar fibrosis. Enhanced lumbosacral ligamentous laxity with childbirth can stretch the conus.3 Adults with spina bifida may experience more pain and sphincter dysfunction with lumbosacral motion.3 Magnetic resonance imaging is preferred for diagnosis. Surgery is the most common treatment. Timing and recommendations are controversial; most advocate surgery only after neurologic deterioration. Deficits may remain or even worsen from surgery.3