Objective: We report the use of CSF drainage for the management of failed Adult Chiari Malformation (ACM) decompression.
Methods: All patients with more than one year follow-up after treatment of their failed ACM were included in this study. They underwent initial decompression between September 1998 and April 2000. Clinical and radiological data were collected initially and at recurrence. Lumbar punctures (LP) were done at recurrence for diagnostic and therapeutic purposes. Opening pressures and symptomatic relief were recorded. Therapeutic options included intermittent LP and ventriculo-peritoneal shunting (VPS).
Results: There were 6 patients (5 females and one male). Their age ranged from 19 to 43 years. Tonsillar descent ranged from 5 to 21 mm. The symptoms recurred 1.5 to 9 months postoperatively (average 5.6 months). Postoperative imaging revealed the presence of CSF flow behind the tonsils and the formation of a retrotonsillar neocistern in all patients. On LP, the opening pressure ranged from 17 to 31 cm of water (average 23 cm). All patients improved after CSF drainage, and four patients underwent VPS. The other patients were treated with repeat LP+/-Acetazolamide. There was significant improvement in all patients, with 18 months follow-up after CSF drainage (range 16-21 months).
Conclusions: Our results suggest a role for CSF drainage in the treatment of some patients with failed ACM surgery. Possible explanations for the failure of ACM surgery in this subgroup include: surgical complications leading to neural hydrodynamic alteration, inadequate initial surgery, and coexistence with another pathology, possibly a mild form of intracranial hypertension. More prospective and hydrodynamic studies are needed to further clarify these issues.