Clinical Correlation of Middle Cerebellar Peduncle Injury Following KOOS Grade III and IV Acoustic Neuroma Resection

Introduction: Identifying factors associated with postoperative deficits following treatment of acoustic neuromas can help guide patient counseling and postoperative care. Thus, we investigated the relationship between postoperative imaging findings of the middle cerebellar peduncle (MCP) suggestive of stroke and postoperative neurological deficits such as ataxia, dysdiadochokinesia, dysmetria, and ataxic dysarthria.

Methods: An institutional review board-approved retrospective study was conducted for patients who underwent treatment for KOOS grade III and IV acoustic neuromas from 2014 to 2022. Collected information included demographics, preoperative and postoperative neurologic function and symptoms, treatment approach, and postoperative outcomes. MCP diameter served as an indirect indicator of stroke due to failed follow-up or absence of either or both postoperative DWI and Flair.

Results: A total cohort of 109 patients were included in the study. The average age was 51.2 years, with an equal distribution of males and females and an average BMI of 29.47 ± 6.86. The average postoperative MCP diameter was significantly greater in patients who did not demonstrate postoperative DWI or Flair (15.77 ± 2.18mm vs 11.03 ± 4.56mm, p < 0.001). With each millimeter increase in postoperative MCP diameter, there was a 50.15% decreased likelihood of dysdiadochokinesia (OR = 0.499, 95% CI [0.258-0.964], p =0.039) and a 24.68% decreased likelihood of requiring an assistive walking device (OR = 0.753, 95% CI [0.569-0.997], p =0.048). MCP diameter was not associated with increased or decreased likelihood in dysmetria and ataxic dysarthria.

Conclusion : Decreased postoperative diameters of the MCP may serve as a predictive factor for declined neurological function after surgery, particularly deficits in performing rapid alternating movements and walking disabilities. Our findings indicate an indirect correlation between MCP diameter and stroke. Future research should further investigate this relationship and assess the predictive value of more direct measures of stroke on neurological deficits occurring after surgery for acoustic neuromas.