Non-invasive Intracranial Pressure Waveform Analysis in Chiari Malformation Type 1: A Pilot Trial

Abstract

This pilot study aimed to investigate the role of Posterior Fossa Decompression (PFD) on the intracranial pressure (ICP) waveform in patients with Chiari Malformation type 1 (CM1). It also sought to explore the relationship between symptom improvement and ICP waveform behavior. This exploratory cohort study evaluated adult patients diagnosed with CM1. The patients underwent PFD using a standard technique at our institution, which involved a 3x3 cm posterior craniectomy and excision of the posterior arch of C1. The ICP waveform was measured using an external strain-gauge device connected to a pin attached to the skull. Measurements were collected pre- and post-PFD, and the P2/P1 ratio was calculated pre- and post-operatively. The pilot study comprised six participants, three men and three women, with ages ranging from 39 to 68 years. The primary symptoms were cerebellar ataxia and typical headaches. The study found that most patients who showed clinical improvement, as judged by the Gestalt method, had a post-operative decrease in the P2/P1 ratio. However, one patient did not show an improvement in the P2/P1 ratio despite a good clinical outcome. This study suggests that the P2/P1 ratio may decrease after PFD. However, we highlight the need for further research with a larger sample size to confirm these preliminary results.