Occult spinal dysraphism--the common combination of lesions and the clinical manifestations in 50 patients.

Fifty patients (26 males, 24 females) aged from birth to 51 years with occult spinal dysraphism were identified. All had Magnetic Resonance (MR) scans carried out. The MR scans were examined to determine the vertebral level of the conus and to see if one or more of the following were present; lipoma, syrinx, dermoid, diastematomyelia, and meningocele. In 43 patients the conus lay below the level of L3, 23 had a lipoma, 23 a meningocele, 20 an open central canal in the spinal cord or a syrinx, 15 a diastematomyelia and 4 a dermoid. The commonest combination of lesions was a long cord, a syrinx or an open central canal in the spinal cord and a lipoma. The diastematomyelias were always associated with a long cord and had the highest incidence of vertebral body anomalies (60%). The most frequent recorded signs were deformities of the feet, short legs, wasting of the calf muscles, weakness of the legs, back pain and bladder dysfunction. Combinations of these occurred with all of the lesions although some had none. Whilst deterioration was seen in about half of the patients, acute deterioration was uncommon and was associated most frequently with a dermoid or an expanded syrinx.