Clinical Fellow Neurosurgery UT Southwestern Medical Center Dallas, Texas, United States
Disclosure(s):
Nida Fatima, MD: No financial relationships to disclose
Introduction: Foramen magnum (FM) decompression with or without duraplasty is considered a common treatment strategy for Chiari Malformation type 1 (CM-I). However, to date, there is little known about the pre-and peri-operative factors which influence the outcomes following surgery. To determine a predictive model of risk factors for worsening following CM-I surgery
Methods: A retrospective review of electronic health records was conducted at an academic tertiary care hospital from 2000-2020. A multivariate cox-proportional hazards regression model was carried out to determine the risk factors and the Kaplan-Meier estimate was plotted to delineate outcomes based on the size of FM. FM was dichotomized based on the sagittal diameter into < 34 mm and ≥34 mm.
Results: A total of 454 patients [females, n=231 (50.9%)] with a median age of 8.0 years (range, 0-21 years) were included in the study. The median duration of follow-up was 21.0 months (range, 3.0-144.0 years). Patients with symptoms consisting of occipital/tussive headache [Hazards ratio (HR): 4.05, 95% Confidence Interval (CI): 1.34-12.17, p=0.01], cranial nerves (HR: 3.46, 95%CI: 1.16-10.2, p=0.02), brainstem/spinal cord (HR: 3.25, 95% CI: 1.01-11.49, p=0.05) and intra-operatively dural opening while leaving arachnoid intact (DO-AI) (HR: 12.2, 95%CI: 1.52-98.1. p=0.01) had a higher risk of clinical worsening postoperatively. Similarly, patients with symptoms of brainstem/spinal cord herniation (HR: 7.9, 95%CI: 2.84-9.50, p=0.03), scoliosis (HR: 1.04, 95%CI: 1.01-2.80, p=0.04), preoperative syrinx (HR:16.1, 95%CI:1.95-132.7, p=0.03) and intra-operative DO-AI (HR:5.03, 95%CI:2.43-8.57, p=0.01) had a significantly higher likelihood while patients undergoing adhesion lysis had 99.6% less likelihood of postoperative worsening of syrinx (HR: 0.004, 95%CI: 0.000-0.33, p=0.01). Kaplan-Meier estimate curve showed that patients with FM size ≥34 mm had significantly better clinical (p=0.02) and syrinx (p=0.03) improvement postoperatively when tonsils were resected.
Conclusion : Our results show that pre- and intra-operative factors might help in better clinical decision-making during CM-I surgery.
