A comparison of prone versus sitting position for the surgical treatment of Chiari malformation type I in children

Abstract

Objective

Posterior fossa decompression and duroplasty (PFD-D) for Chiari type I malformation (CM-I) is usually performed in the prone position. Nevertheless, few centres routinely perform it in sitting position. This study aims to compare, for the first time in the literature, the peri-operative surgical and anaesthesiologic outcomes of two similar cohorts of paediatric patients with CM-I treated with PFD-D in prone and sitting position.

Methods

Patients younger than 17 years old, who had undergone PFD-D for CM-I performed by a single surgeon between November 2013 and June 2024, were included. Surgical time, intraoperative and perioperative events, and post-operative complications were recorded. All patients had at least a 10-month follow-up.

Results

Twenty-seven patients were operated in the prone position [mean age: 9.3 years, M/F: 0.59] and twenty-five in the sitting position [mean age: 11.3 years, M/F 0.47]. 15/27 (55 %) in the prone group and 13/25 (52 %) in the sitting group had pre-operative syringomyelia. The mean operative time in sitting was significantly shorter (143 min) compared to 175 min in the prone position (p < 0.001), particularly in high BMI > 30 patients. Complications in the prone cohort included 3 post-operative pseudomeningocele (11.1 %), 3 aseptic meningitis (1 %), 1 CSF leakage (3.7 %), and 1 post-infective hydrocephalus requiring VP shunt insertion (3.7 %). In the sitting position, 1 patient developed pseudomeningocele (4 %), and another patient had a post-operative hydrocephalus (4 %) successfully treated with an endoscopic third ventriculostomy. No patient in this series developed clinical air embolism or tension pneumocephalus.

Conclusions

The study did not show any significant difference in the surgical and anaesthetic complications between the two groups of patients. Sitting position for CM-I when performed by a trained neuro-anaesthesiologic team is a safe option with similar clinical outcomes compared to the prone position.