Management of hydromyelia.

The authors review their experience in the management of 22 patients with hydromyelia over a 26-month period. Ten children had Chiari I malformations and hydromyelia; 4 children had myelomeningoceles (3 with large thoracic spinal cord cavitations and 1 with cervical hydromyelia); 6 children had distal hydromyelia associated with tethered cords and occult dysraphism; and 2 patients had cavitation subsequent to arachnoiditis. All patients were investigated preoperatively with MRI and intraoperatively with ultrasound. These neurodiagnostic examinations dictated the type of surgical intervention. Patients with Chiari I or Chiari II malformations, cervical hydromyelia, or basal arachnoiditis underwent decompression of the hindbrain malformations, myelotomy with drainage of the cyst, and placement of a stent. When the area of hydromyelia extended to the obex, as demonstrated by intraoperative ultrasound, the obex was plugged. Cyst-pleural shunts were placed in the children who had myelomeningoceles and thoracic hydromyelia. Patients with distal hydromyelia underwent modified terminal ventriculostomy. The classical presentation of brachial amyotrophy and dissociated sensory loss was present in only 3 patients. Progressive scoliosis without neurological deficit, pain, and Lhermitte's phenomenon were common presentations. The patients with tethered cords were generally asymptomatic from their cysts. The authors discuss operative technique, utilization of intraoperative ultrasound, and surgical outcome.