Intracranial pressure changes during early postoperative mobilization in patients with chronic subdural hematoma

Abstract

Background

Passive subdural drainage is used to reduce the risk of chronic subdural hematoma (cSDH) recurrence and mortality. However, the effects of patient positioning on intracranial pressure (ICP) during passive drainage remain unclear.

Objective

To examine how subdural drainage and patient positions influence postoperative ICP in cSDH patients with a subdural passive drainage system.

Methods

This was a prospective, single-center observational cohort study. Eleven patients (mean age 78 years) underwent burr hole evacuation for cSDH with placement of a subdural drain connected to a bile bag system. An ICP probe was placed in the subdural space posteriorly via the same burr hole. During the first 48 h, ICP was measured in supine, 30° head elevation, and sitting positions before and after removal of the subdural drain. Given the small sample size, the study was a priori considered hypothesis‑generating; the width of confidence intervals and potential type II error are therefore emphasised throughout. Also, the associations between ICP and radiographic parameters (midline shift, hematoma size, pneumocephalus) were assessed.

Results

When all positions were combined, mean ICP with the drain in situ was − 2.5 (− 4.8 to − 0.2) mmHg versus − 0.5 (− 2.9 to 1.9) mmHg after removal (p = 0.233). Position-specific differences after vs before removal were likewise small and non-significant: supine -1.9 (-7.8 to 4.1, p = 0.537), 30° -2.6 mmHg (-8.5 to 3.3, p = 0.378), sitting -3.6 (-9.8 to 2.6, p = 0.244) mmHg; mixed-effects modelling confirmed these findings.

Greater midline shift and hematoma volume were associated with higher ICP, whereas larger pneumocephalus volumes correlated with lower ICP.

Conclusions

After burr-hole evacuation of cSDH, ICP remained within normal physiological limits across all head positions, both with the subdural drain in situ and after its routine removal at 24 h. Providing that the drainage height is adjusted to the pivot point for CSF pressure at shoulder level, mobilization—even to the upright position—did not provoke dangerously low ICP. These data, together with emerging randomised evidence, support early mobilisation after cSDH surgery; nonetheless, confirmation in adequately powered multicentre trials is required before firm practice recommendations can be issued.