Introduction: Factors influencing the development of syringomyelia in Chiari I are still unknown, and thus the aim of this study was to further elucidate associations with syrinx formation.
Methods: After approval by the Wayne State University Institutional Review Board, medical records of Chiari I patients during 2010-2017 were retrospectively analyzed. Statistical calculations were obtained using student t-test and fisher exact test, with significance considered if p<0.05.
Results: Patients with appropriate follow up were grouped into those with syrinx (N=14) and those without (N=52). The demographics between the two groups were similar with respect to gender, presenting symptoms, and reoperation rate (p>.05). The mean age for patients with syrinx (9±5.8) was higher than those without syrinx (6.2±4.3; p=.05). The mean cerebellar ectopia in millimeters in the syrinx group was 14.4±6.4 compared to 12.5±4.4 in those without syrinx (p>.05). The posterior fossa volume, modified C-1 cerebellar tonsil ectopia, and the skull base angle were not statistically significant irrespective of syringomyelia (p>.05). Next, the authors measured an occiput slope angle by drawing a line from internal occipital protuberance inflection point to opisthion, joining it with the McRae line and measuring the angle in between. Children = 10 years old with syrinx had narrower slope angle (123.3±8.4) compared to those without syrinx (132.3±8.4; p<.05).
Conclusions: Our study suggests that unlike cerebellar tonsillar descent and posterior fossa volume, there is a statistically significant association between syrinx and the occiput slope angle in young children. Knowledge of this association might be crucial in properly selecting patients for Chiari decompressive surgery.
Patient Care: Knowledge of the factors that might influence syrinx formation in patients with Chiari I is crucial during the selection process of patients for a decompressive surgery.
Learning Objectives: By the conclusion of this session, participants should be able to identify factors that are associated with the development of syringomyelia in pediatric patients with Chiari I malformation. The participants should also be aware of the association between the occiput slope angle and syrinx development, as well as methods to measure the slope angle.