Chiari Malformation with and without Syringomyelia: Surgical Technique and Outcome in 88 Adult Patients

Objective:  This study identified the relationship between posterior fossa craniectomy, expansion neuroplasty, and radiological appearances in patients with Chiari malformation with and without clinical syringomyelia with the surgical outcomes in an attempt to correct the lesion. Materials & Methods:  Eighty-eight patients with Chiari malformation (CM) were included in the study where 70 had associated syringomyelia. All underwent posterior fossa craniotomy, expansion duroplasty without fiddling with cerebellar tonsils. Patients were evaluated at 1 month, 3 months, and 12 months. The MRI studies were done at 12 months when symptomatic relief and radiological findings were evaluated and matched. Results:  Most of the patients were young adults between the age range of 25 – 40 years. The most common complication was pseudomeningocele (5.68%) formation followed by CSF leak (4.54%). Patients with a longer history of Chiari malformation or syrinx-related symptoms and signs had partial relief in symptoms and signs. The poor outcome as expected was seen in patients with atrophic changes in upper limbs and hypertonia in lower limbs, especially in patients with loss of joints position sense and poor balance. Patients showed maximum improvement in headaches both suboccipital as well as generalized. Syringomyelia was decreased in size in 49 patients and remained unchanged in 21.  Dysesthesias were improved in 31 patients. Conclusion:  Clinical improvement was related to the expansion of the posterior fossa and subarachnoid cistern and reduction in the size of the syrinx. Surgical decompression of the posterior fossa should create adequate space for its contents and reduce the syrinx cavity. The relationship between symptomatic improvement and radiological findings is not always linear. Keywords:  Chiari Malformation, Tonsillar Herniation, Syringomyelia, Duroplasty.