TREATMENT OF HYDROMYELIA IN SPINA-BIFIDA

BACKGROUND Cavitation of the spinal cord (hydrosyringomyelia) seems to be common in spina bifida patients, although the overall clinical and radiological incidence has very rarely been analyzed. The real incide nce of the condition is, in fact, difficult to assess as patients with this complication may remain relatively asymptomatic. The mechanisms accounting;for the occurrence of hydrosyringomyelia in myelodysplasia are still a subject of debate. Similarly, the indications for the surg ical treatment are still to be defined and its results to be assessed. METHODS In this study, 142 patients with spina bifida were screened w ith magnetic resonance imaging (MRI) to determine the incidence of hyd romyelia. Thirty-two patients presented a cavitating lesion on MRIs of which 18 were not a cause of symptoms and 14 were. Clinical character istics of the lesions and their correlation to the radiological pictur e were analyzed. All the symptomatic children underwent surgical treat ment. Outcomes were evaluated and correlated also with the MRI finding s. RESULTS A correlation between the presence of symptomatology and th e extension and/or dilation of the hydromyelia was observed. A signifi cant relationship between the presence of symptoms and adequate contro l of associated hydrocephalus was also noted. No correlation was obser ved between the presence of hydromyelia and the level of the myelomeni ngocele or the degree of ventricular dilation in those cases that pres ented with hydrocephalus. The mean age at hydromyelia diagnosis for al l patients affected was 3.9 years and, in particular, 4 years for thos e patients who presented with symptoms. A total of 15 operations were performed in the 14 symptomatic patients.. Seven direct procedures wer e carried out to drain the hydromyelia: five hydroperitoneal shunt ins ertions and two hydrosubarachnoid shunting procedures. Eight indirect treatments were performed to eliminate the filling mechanism of the hy dromyelia: five posterior fossa decompressions, two ventriculoperitone al shunt revisions, and one spinal cord untethering procedure with ter minal syringostomy. All patients improved postoperatively, except one who remained clinically stable at follow-up. This patient had undergon e a posterior fossa decompression followed by a hydrosubarachnoid shun ting procedure. CONCLUSIONS The incidence of syringohydromyelia is act ually higher than that reported in the literature, although not all le sions are symptomatic. The radiological picture may be helpful in plan ning a more careful follow-up program for patients theoretically at ri sk for neurologic deterioration. Surgical treatment is possible with g ood results in the majority of cases and should be carried out as soon as possible before further deterioration occurs. Not all symptoms res pond equally to treatment. Generally, improvement of clinical status c orrelates with a reduction in size of the hydromyelic cavity on MRI. ( C) 1998 by Elsevier Science Inc.