CSF Flow Improvement after Chiari Malformation Type I Surgery as a Prognostic Indicator for Clinical Improvement

Objective: Chiari malformation type I (CMI) is a common neurological condition for which surgical decompression is the standard treatment. We aim to establish that cerebral spinal fluid (CSF) flow as a potential objective indicator of surgical efficacy in symptom alleviation after decompression.

Methods: We performed a retrospective, two-center analysis of patients who underwent a suboccipital craniotomy due to symptomatic CMI. Qualitative CSF flow studies pre- and postoperative were analyzed to determine if any improvement in CSF flow was achieved. Finally, symptoms including headache, dizziness, weakness, and others were recorded, observing if improvement, worsening, or unchanging status was present.

Results: Forty-nine patients were identified who met inclusion criteria among four different surgeons at two institutions between 2010 and 2017. The average age was 36.06 years with 47 females and 2 males. Post decompression, 41 patients demonstrated improved CSF flow via flow studies. Regarding clinical outcomes, 38 patients were reported to be improved symptomatically by the attending physician on follow-up, 10 were unchanged, and 1 was worse. Subsequently, patients were divided into two groups: Group A, composed of patients with improved CSF flow, and Group B, with those with no improved CSF flow. Group A had a mean age of 34.82 years and an average tonsillar herniation distance of 8.30 mm vs Group B, which had a mean age of 42.25 years and an average tonsillar herniation of 8.56 mm (p < 0.05 and p = 0.40, respectively). Postoperatively, improved CSF flow (Group A) was associated with improved clinical outcomes, whereas a non-improved CSF flow (Group B) was associated with poorer outcomes (p = 0.024). More specifically, Group A demonstrated superior improvement of symptoms compared with Group B among the total patient population including headache (50 vs. 37.5% improvement), neck pain (66.67 vs. 33.33%), dizziness (78.5 vs. 50%), vision (84.2 vs. 80%), and weakness (100 vs. 66.67%). Group B had the only patient who did worse on clinical follow-up and had the worst headaches postoperatively.

Conclusion: Patients with CMI often present with a constellation of symptoms. We demonstrated a significant association between improved CSF flow post-decompression and symptom improvement. Further, our study suggests that improved CSF flow, post-decompression, could represent an objective indicator for positive patient outcomes and symptoms betterment.

No conflict of interest has been declared by the author(s).