# The Advantage of Microelectrode Recording When Pneumocephalus Threatens the Precise Placement of a Deep Brain Stimulator

## TL;DR

This paper discusses how microelectrode recording helps correct brain stimulation placement errors caused by pneumocephalus during surgery.

## Contribution

The study highlights the importance of using microelectrode recording to adjust deep brain stimulation lead placement in the presence of pneumocephalus.

## Key findings

- Microelectrode recording revealed a mismatch between imaging-based targeting and actual subthalamic nucleus localization.
- Adjusting the lead position based on MER data improved therapeutic outcomes and motor benefits.
- Pneumocephalus-induced brain shifts can be corrected using MER and postoperative validation.

## Abstract

A 69-year-old woman with Parkinson’s disease underwent left subthalamic nucleus (STN) deep brain stimulation (DBS). Intraoperative awake microelectrode recording (MER) was used to confirm targeting.

MER and stimulation mapping revealed a short STN segment on the central pass, absent STN activity on the lateral pass, and low thresholds for capsular side effects. The data suggested a mismatch between the planned imaging-based trajectory and the localization of STN using physiology.

A substantial adjustment based on MER was required, giving up the ‘fork’ in the brain. The lead was repositioned 3.4 mm posterior and 2.9 mm medial to the initial central pass (4.9 mm vector). Final placement produced robust motor benefit and a desirable therapeutic window for programming.

Asleep image-guided workflows assume static intracranial anatomy: pneumocephalus can induce millimetric brain shift. This case demonstrated a pneumocephalus-related displacement and how MER, stimulation thresholds, and postoperative atlas-based validation can be employed to correct it.

This case illustrates how intraoperative pneumocephalus can compromise targeting in deep brain stimulation.

Microelectrode recording provided critical confirmation, guided corrective lead adjustments, and safeguarded therapeutic outcomes, emphasizing the value of physiology-based targeting alongside modern imaging techniques.