Impact of Additional Tonsillar Manipulation or Intra-articular Distraction on Syrinx Remission for Type B Basilar Invagination

BACKGROUND AND OBJECTIVES: The impact of adjunctive techniques, such as cerebellar tonsillar manipulation (TM) (ie, tonsillectomy and coagulation) and intra-articular distraction, on the progression of syrinx reduction remains unclear. This study aims to investigate the factors influencing syringomyelia regression in patients with type B basilar invagination following craniovertebral junction fixation. METHODS: A retrospective analysis was performed on data from patients with type B basilar invagination and syringomyelia who underwent craniovertebral junction fixation supplemented by one of the following techniques: epidural decompression, TM, or intra-articular distraction. The analyzed data encompassed demographic, imaging, and surgical parameters. Syringomyelia remission was defined as a reduction in the maximal anteroposterior diameter of the syringomyelia by 50% on sagittal MRI. Survival analysis was performed to determine the median times to syringomyelia remission and discharge. Cox regression analysis was used for the multivariate analysis. RESULTS: A total of 77 patients were included in the study. Cox regression analysis identified factors influencing syringomyelia resolution, including TM (P = .007) and intra-articular distraction (P = .010). The median time to syrinx remission was 5.0 months in the fixation with TM group, 16.0 months in the fixation with epidural decompression group, and 6.0 months in the fixation with distraction group (P < .05). Patients who underwent intra-articular distraction had a shorter postoperative length of stay (P < .001), a reduced incidence of aseptic meningitis (P < .001), and a reduction in the need for lumbar drainage (P < .001), compared with those who underwent fixation with TM. CONCLUSION: Additional TM contributes to earlier syringomyelia remission; however, it is also associated with an increased incidence of aseptic meningitis, lumbar drainage, and delayed discharge. By contrast, additional intra-articular distraction is linked to earlier syringomyelia remission, lower complication rates, and a shorter hospital stay.