There are various surgical approaches to treat Chiari I malformation. In spite of the good clinical results that are reported with most of them, there is still controversy about the optimal treatment of this pathology.
Objective: To compare the clinical and radiological results of surgical treatment of the Chiari I malformation with suboccipital craniectomy, posterior arch of C1 resection with or without dural graft, analyzing clinical and radiological findings and describing the complications.
Material and methods: Retrospectively clinical cases series of patients who underwent Chiari I malformation surgery between 1998 and 2006 in the Hospital Germans Trias i Pujol in Badalona. The inclusion criteria consisted in: patients older than 18 years, who have had surgery in our hospital, detailed neurological examination before and after surgery (calculating the EDSS scale punctuation), craniospinal magnetic resonance imaging before and after surgery and minimal follow up period of 6 months. The election of the surgical approach was left to the discretion of the main surgeon. Patients were divided in two groups depending of the surgical technique: Group A (with dural graft) and Group B (without dural graft). To evaluate the morphological results in both groups, measurements of the position of the fastigium above a basal line in the midsagittal T1 weighted magnetic resonance images were obtained. In patients with syringomyelia, siringo-to-cord ratio was measured before and after surgery. To evaluate the clinical results, neurological examination was recorded in both groups before and after surgery.
Results: The mean age of Group A patients was 47 (-/+12.89) years, and of Group B was 38.3 (-/+7.77) years. Mean follow up period was 2.48 (-/+2.44) years in Group A and 4.2 (-/+4.46) in Group B. Creation of an artificial cisterna magna was observed en 35.7% of Group A patients and only in 3.5% of Group B patients (p=0.022). In 8 patients front Group A, 8 patients (28.6%) an upward migration of the cerebellum was seen, whereas any of the Group B patients presented it (p=0.022) Siringo-to-cord ratios were decreased in both groups without significant differences. All of the Group A patients improved their clinical exploration. In Group B, 60% of the patients improved and the 40% left maintained clinical stability. Any patient worsened. All patients that maintained clinical stability belonged to Group B, the differences between the two groups were statistically significant (p=0.04). Five patients presented immediate surgical complications (2 pseudomeningoceles, 2 meningitis and 1 hydrocephalus). All this patients where operated with dural graft (p=0.049).
Conclusions: According to our study, suboccipital craniectomy with resection of the posterior arch of C1 and dural graft shows better clinical and radiological results than without dural graft. Nevertheless this technique can increase the incidence of surgical complications.