The effect of tonsillar coagulation on syringomyelia and clinical findings in chiari malformation Type 1

Chiari Malformation Type I (CM-I) results from developmental insufficiency of the posterior fossa, leading to downward displacement of the cerebellar tonsils through the foramen magnum. It commonly presents with occipital and nuchal pain, while syringomyelia is a frequent radiological finding. This study aimed to assess the impact of cerebellar tonsil coagulation on clinical and radiological outcomes in CM-I surgery. Seventy-eight patients operated for CM-I and followed for at least 6 months were divided into two groups: those who underwent tonsillar coagulation (Group A) and those who did not (Group B). Demographic and clinical features, postoperative Chicago Chiari Outcome Scale (CCOS) scores, syringomyelia regression rate, complications, and hospital stay were compared using appropriate statistical methods. There were no significant differences between the groups regarding age, sex, tonsillar herniation, or preoperative syringomyelia (p>0.05). The median CCOS score was significantly higher in Group A (14 vs 13; p=0.002). In patients with preoperative syringomyelia, postoperative regression was more frequent in Group A (79% vs 53%), although this was not statistically significant (p=0.16). Regression rates for headache, paresthesia, dizziness, and dysphagia were higher in Group A but the differences were not statistically significant (p>0.05). Complication rates and length of hospital stay were also comparable between the groups. In conclusion, overall functional improvement was significantly higher in the tonsil coagulation group. However, no significant superiority was observed in symptom-specific improvement, syringomyelia regression, complications, or hospital stay. Further and long-term studies are needed to establish its necessity for routine practice. Keywords: Chiari Malformation Type 1, cerebellar tonsil coagulation, Chicago Chiari Outcome Scale, syringomyelia