A nomogram for estimating intracranial pressure using acute subdural hematoma thickness and midline shift

Chun-Chih Liao,Feipei Lai,Heng-Chun Liao,Furen Xiao

doi:10.1038/s41598-020-77667-x

Abstract

Although criteria for surgical treatment of acute subdural hematoma (SDH) have been proposed, interaction exists between SDH, midline shift (MLS), and intracranial pressure (ICP). Based on our half sphere finite-element model (FEM) of the supratentorial brain parenchyma, tools for ICP estimation using SDH thickness (SDHx) and MLS were developed. We performed 60 single load step, structural static analyses, simulating a left-sided SDH compressing the cerebral hemispheres. The Young's modulus was taken as 10,000 Pa. The ICP loads ranged from 10 to 80 mmHg with Poisson's ratios between 0.25 and 0.49. The SDHx and the MLS results were stored in a lookup table. An ICP estimation equation was derived from these data and then was converted into a nomogram. Numerical convergence was achieved in 49 model analyses. Their SDHx ranged from 0.79 to 28.3 mm, and the MLS ranged from 1.5 to 16.9 mm. The estimation formula was log(ICP) = 0.614–0.520 log(SDHx) + 1.584 log(MLS). Good correlations were observed between invasive ICP measurements and those estimated from preoperative SDHx and MLS data on images using our model. These tools can be used to estimate ICP noninvasively, providing additional information for selecting the treatment strategy in patients with SDH.

Highlights

Criteria for surgical treatment of acute subdural hematoma (SDH) have been proposed, interaction exists between SDH, midline shift (MLS), and intracranial pressure (ICP)
Since interaction exists between SDHx, MLS, ICP, and other factors including the severity of brain atrophy[9], a compound model including these variables is desirable
The values of SDHx and MLS from 49 successful simulation results were plotted on Fig. 1A; the values were used to construct the lookup table

Summary

Introduction

Criteria for surgical treatment of acute subdural hematoma (SDH) have been proposed, interaction exists between SDH, midline shift (MLS), and intracranial pressure (ICP). Based on our half sphere finite-element model (FEM) of the supratentorial brain parenchyma, tools for ICP estimation using SDH thickness (SDHx) and MLS were developed. Good correlations were observed between invasive ICP measurements and those estimated from preoperative SDHx and MLS data on images using our model These tools can be used to estimate ICP noninvasively, providing additional information for selecting the treatment strategy in patients with SDH. Details about MLS measurement and its automation were reviewed in our previous p ublication[5] Based on these quantitative evaluations, clear-cut SDH thickness (SDHx), MLS, and ICP thresholds for surgical treatment of aSDH have been proposed in existing clinical practice guidelines[1,6]. Neurosurgeons can determine the treatment strategy without invasive and sometimes costly ICP measurement

Methods

Results

Conclusion