gms | German Medical Science

Objective: The osteo-dural decompression of the cerebellar tonsils at the cranio-cervical junction is generally considered the most effective treatment for syringomyelia-Chiari I complex. However, there is much controversy concerning a great number of surgical adjuvants to the standard bony decompression. Here an extra-arachnoidal cranio-cervical decompression (CCD) without duroplasty is described and the surgical results are reported.

Methods: Between 2000 and 2005, twenty-four adult patients underwent surgery for symptomatic syringomyelia-Chiari I complex not associated with hydrocephalus. In all cases, the surgical procedure consisted of a limited suboccipital craniectomy and laminectomy of C1 (when necessary C2 as well) followed by dural opening leaving the arachnoid membrane intact. The dura mater is left open and is stitched laterally to the muscles.

Results: With a mean clinical long-term follow-up of 44 months (range, 12-78 mo), neurological disturbances improved in twenty-one of twenty-four patients (87.5%) as result of extra-arachnoidal CCD. The postoperative complications occurred when the arachnoid membrane was accidentally violated (4 cases, 16.6%). The complications included aseptic meningitis (one patient), nucal pseudomeningocele (two patients) and postoperative hydrocephalus requiring a ventriculoperitoneal shunt (one patient). Finally, one patient received an additional C2 laminectomy in order to achieve an improvement in symptoms and syrinx shrinkage. Postoperative MRI studies demonstrated that the syrinx decreased in size or collapsed in 20 patients (83.3%) and stabilized in 4 (16.7%).

Conclusions: The extra-arachnoidal CCD is a safe and effective treatment for syringomyelia associated with Chiari I malformation in adults without intraoperative evidence of adhesive arachnoiditis. However, a larger number of patients and longer follow-up will be necessary to determine the efficacy of extra-arachnoidal CCD.