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Relationship Between Laser Doppler Signals and Anatomy During Deep Brain Stimulation Electrode Implantation Toward the Ventral Intermediate Nucleus and Subthalamic Nucleus

Wårdell, Karin MSc, PhD*; Zsigmond, Peter MD‡,§; Richter, Johan MD*,§; Hemm, Simone MSc, PhD*,¶

doi: 10.1227/NEU.0b013e31827e5821
Instrumentation and Technique

BACKGROUND: Deep brain stimulation (DBS) requires precise and safe navigation to the chosen target. Optical measurements allow monitoring of gray-white tissue boundaries (total light intensity [TLI]) and microvascular blood flow during stereotactic procedures.

OBJECTIVE: To establish the link between TLI/blood flow and anatomy along trajectories toward the ventral intermediate nucleus (Vim) and subthalamic nucleus (STN).

METHODS: Stereotactic laser Doppler measurements were obtained with millimeter precision from the cortex toward the Vim (n = 13) and STN (n = 9). Optical trajectories of TLI and blood flow were created and compared with anatomy by superimposing the Schaltenbrandt-Wahren atlas on the patients' pre- and postoperative images. Measurements were divided into anatomic subgroups and compared statistically.

RESULTS: Typical TLI trajectories with well-defined anatomic regions could be identified for the Vim and STN. TLI was significantly lower (P < .001) and microvascular blood flow significantly higher (P = .01) in the Vim targets. Of 1285 sites, 38 showed blood flow peaks, 27 of them along the Vim trajectories. High blood flow was more common close to the sulci and in the vicinity of the caudate/putamen. Along 1 Vim trajectory, a slight bleeding was suspected during insertion of the probe and confirmed with postoperative computed tomography.

CONCLUSION: Laser Doppler is useful for intraoperative guidance during DBS implantation because simultaneous measurement of tissue grayness and microvascular blood flow can be done along the trajectory with millimeter precision. Typical but different TLI trajectories were found for the Vim and STN.

ABBREVIATIONS: a.u., arbitrary unit

Cd, caudate nucleus

DBS, deep brain stimulation

IC, internal capsule

LDPM, laser Doppler perfusion monitoring

LSS, Leksell Stereotactic System

STN, subthalamic nucleus

Put, putamen

TLI, total light intensity

Vim, ventral intermediate nucleus

Departments of *Biomedical Engineering and

Clinical and Experimental Medicine, Linköping University, Linköping, Sweden;

§Department of Neurosurgery, County Council of Östergötland, Linköping, Sweden;

University of Applied Sciences and Arts Northwestern Switzerland, Institute for Medical and Analytical Technologies, Muttenz, Switzerland

Correspondence: Karin Wårdell, MSc, PhD, Department of Biomedical Engineering, Linköping University, 581 85 Linköping, Sweden. E-mail:

Received June 01, 2012

Accepted November 01, 2012

Copyright © by the Congress of Neurological Surgeons