Management of Chiari I Malformation (CM): Analysis of the Clinical Outcome after Craniovertebral Decompression with Arachnoidal Sparing Technique

Objective: The purpose of this study was to determine the CSF values before and after surgical treatment of adult patients with chiari I malformation (CM) and to estimate the correlation of clinical outcome and postoperative phase-contrast MRI data. Material and Methods: A total of 67 CM patients were operated during 2005 to 2010. Syringomyelia was present in 41 cases. In 55 patients the uniform posterior craniovertebral decompression consisted of a suboccipital craniectomy, a C1 laminectomy and duraplasty with arachnoidal sparing was used. Remaining patients underwent various surgical procedures such as ETV, VP shunts, or combination with craniovertebral decompression and were not included in this study. Postoperative complication consisted of two CSF fistulas and one pseudomeningocele formation in cases when arachnoidea was unintentionally perforated. Improvement in main group was observed in 47 patients and no change in 8 of them. To determine the normal values of CSF flow at the C2-C3 level 16 healthy subjects underwent phase-contrast MRI. Same study performed in main group preoperatively. Postoperative results were analyzed by means of control study 6 month postoperatively and compared with clinical outcome. Results: After surgery a good clinical outcome was achieved. The CSF-flow values improved. We observed statistically significant correlation between postsurgical improvement and MRI data. Conclusions: Craniovertebral decompression and duraplasty without subarachnoidal manipulations is a suitable treatment modality for symptomatic CM with minor possible complications. Cardiac gated phase-contrast MRI is a valuable method in determining the CSF disturbances in patients with CM, which strongly correlate with clinical outcome.