Displacements of Brain Due to Positional Changes during Stereotactic Operations

Abstract

Lumbar pneumoencephalograms, performed before craniotomy in the stereotactic procedure, from patients in the upright and supine positions demonstrate shifts (up to 2.5 mm) of deep-seated intracerebral structures, influenced by gravity. After trephining the burr hole with opening of a free communication of air into the subdural space, dislocation of the brain (up to 2 mm) in the direction of gravity may also be encountered. Thus, for exact localization of the stereotactic target point al-lowances for extracerebral air collections and consequent shifts of deep-seated target structures must be made.

Fabrication of a positional brain shift phantom through the utilization of the frozen intermediate hydrogel state

“…This is partly due to the difficulty of imaging human subjects in non-supine positions with magnetic resonance (MR) imaging (MRI) and the more general unsuitability of computerised tomography (CT) imaging due to radiation exposure, especially in studies that require multiple sequential scans. To date, only a handful of MR and CT imaging studies have investigated PBS (Thulin et al, 1972;Hill et al, 1998;Rice et al, 2013;Schnaudigel et al, 2010;Monea et al, 2012;Mikkonen and Laakso, 2019;Ji et al, 2004;Ji and Margulies, 2007;Zappalá et al, 2021), and of these studies, only a small number of positional transitions have been looked at. These studies, however, repeatedly show that patient repositioning alone can be sufficient to induce clinically significant brain shift (>1 mm).…”

Fabrication of a Positional Brain Shift Phantom Through the Utilization of the Frozen Intermediate Hydrogel State

“…This is partly due to the difficulty of imaging human subjects in non-supine positions with magnetic resonance (MR) imaging (MRI) and the more general unsuitability of computerised tomography (CT) imaging due to radiation exposure, especially in studies that require multiple sequential scans. To date, only a handful of MR and CT imaging studies have investigated PBS [1][2][3][4][5][6][7][8][9], and of these studies, only a small number of positional transitions have been looked at. These studies, however, repeatedly show that patient repositioning alone can be sufficient to induce clinically significant brain shift (>1 mm).…”