Targeting of the Subthalamic Nucleus in Patients with Parkinson’s Disease Undergoing Deep Brain Stimulation Surgery

Abstract

Precise stereotactic targeting of the dorsolateral motor part of the subthalamic nucleus (STN) is paramount for maximizing clinical effectiveness and preventing side effects of deep brain stimulation (DBS) in patients with advanced Parkinson's disease. With recent developments in magnetic resonance imaging (MRI) techniques, direct targeting of the dorsolateral part of the STN is now feasible, together with visualization of the motor fibers in the nearby internal capsule. However, clinically relevant discrepancies were reported when comparing STN borders on MRI to electrophysiological STN borders during microelectrode recordings (MER). Also, one should take into account the possibility of a 3D inaccuracy of up to 2 mm of the applied stereotactic technique. Pneumocephalus and image fusion errors may further increase implantation inaccuracy. Even when implantation has been successful, suboptimal lead anchoring on the skull may cause lead migration during follow-up. Meticulous preand intraoperative imaging is therefore indispensable, and so is postoperative imaging when the effects of DBS deteriorate during follow-up. Thus far, most DBS centers employ MRI targeting, multichannel MER, and awake test stimulation in STN surgery, but randomized trials comparing surgery under local versus general anesthesia and additional studies comparing MER-STN borders to high-field MRI-STN may change this clinical practice. Further developments in imaging protocols and improvements in image fusion processes are needed to optimize placement of DBS leads in the dorsolateral motor part of the STN in Parkinson's disease.

More Than Just the Level of Consciousness: Comparing Asleep and Awake Deep Brain Stimulation

“…Preoperatively, both awake and asleep procedures benefit from magnetic resonance imaging (MRI) with higher magnetic field strengths to better delineate basal ganglia structures such as the subthalamic nucleus (STN), especially true for nowadays with available 3 T and 7 T MRI. 10 A potential confound in analyzing outcomes of asleep DBS relates to different intraoperative imaging methods. Intraoperative MRI (iMRI) gives real-time feedback to guide the trajectory planning before electrode placement 11 so that targeting can be adjusted after the dura is opened.…”

Deep Brain Stimulation: Emerging Tools for Simulation, Data Analysis, and Visualization

“…Since DBS implantations require precise and safe targeting of a specific brain structure, stereotactic systems that rely on high quality brain imaging and surgical planning systems are required. Intraoperative recording of physiological signals is used as a complement for target verification and compensation of trajectory deviations due to brain shift ( Hemm and Wårdell, 2010 ; van den Munckhof et al, 2021 ). With novel DBS lead designs, the postoperative programming of stimulation results in many available options which require the need for support systems.…”

Surgical Strategy for Directional Deep Brain Stimulation

“…3A ). 26 , 29) With a D-lead, some authors proposed that directional segments (2, 3) should be placed in sweet spots, 23 , 30) as decided from microelectrode recording (MER) and test stimulation, but no specific indicators were shown. In our hospital, 4 was often the optimal stimulation site in the conventional arrangement in STN-DBS and Vim-DBS, so we have changed the arrangement so that 2 and 3 in the part where the kinesthetic response and tremor rhythm are recorded by MER.…”

“…Steigerwald et al and Fricke et al therefore noted that the measurement of the TW with OS should be tried as a first step, focusing the monopolar review on the DS at the level of the best TW on OS. 23 , 29 , 30) The Informity tool for monopolar review is available from Abbott. Informity works with a user-friendly interface on an iPad (Apple), and users can easily switch between each contact alone, combinations of two contacts, and OS using all three contacts, gradually increasing the stimulus, and recording amplitude and symptoms with effects and side effects ( Fig.…”