Background: Microelectrode recording helps surgeons accurately localize boundaries of the subthalamic nucleus (STN) and surrounding structures in deep brain stimulation.
Objective: To describe a novel adaptation of the Ben’s gun device to optimize efficient mapping.
Methods: Patients who underwent STN deep brain stimulation over a 3-year period were reviewed. For the final year, the Ben’s gun was rotated 45 degrees and the target was offset 1.4 mm lateral and anterior in the plane orthogonal to the intended trajectory to allow for simultaneous parallel tracks at target, 2.8 mm anterior (localizing the front of STN), and 2.8 mm lateral (identifying the internal capsule). Prior to this step, the initial pass consisted of 1-2 tracks with the frame center targeted to STN. Primary outcome measure was the number of passes required for accurate localization of the nucleus and boundaries.
Results: 83 electrodes were implanted in 45 patients (mean age 62, range 37-78 years), of which 29 electrodes were placed using the new technique. One electrode (4%) required more than one pass using the new technique compared with 36 (67%) using the older technique (p < 0.01). Distance from original target to final electrode position increased from 0.67 +/- 0.13 mm to 1.06 +/- 0.15 mm (p < 0.05) with a greater tendency to move the final electrode position posteriorly. There was no statistically significant difference in benefit from neurostimulation.
Conclusion: This technique facilitates reliable localization of the STN with fewer passes, possibly decreasing risks associated with more passes and longer duration of surgery.
From: Multi-tract Orthogonal Microelectrode Localization of the Subthalamic Nucleus: Description of a Novel Technique by Miller et al.