Relative Contribution of Magnetic Resonance Imaging, Microelectrode Recordings, and Awake Test Stimulation in Final Lead Placement during Deep Brain Stimulation Surgery of the Subthalamic Nucleus in Parkinson’s Disease

Abstract

<b><i>Introduction:</i></b> For deep brain stimulation (DBS) surgery of the subthalamic nucleus (STN) in Parkinson’s disease (PD), many centers employ visualization of the nucleus on magnetic resonance imaging (MRI), intraoperative microelectrode recordings (MER), and test stimulation in awake patients. The value of these steps is a subject for ongoing debate. In the current study, we determined the relative contribution of MRI targeting, multitrack MER, and awake test stimulation in final lead placement during STN DBS surgery for PD. <b><i>Methods:</i></b> Data on PD patients undergoing MRI-targeted STN DBS surgery with three-channel MER and awake test stimulation between February 2010 and January 2014 were analyzed to determine in which MER trajectory final leads were implanted and why this tract was chosen. <b><i>Results:</i></b> Seventy-six patients underwent implantation of 146 DBS leads. In 92% of the STN, the final leads were implanted in one of the three planned channels. In 6%, additional channels were needed. In 2%, surgery was aborted before final lead implantation due to anxiety or fatigue. The final leads were implanted in the channels with the longest STN MER signal trajectory in 60% of the STN (38% of the bilaterally implanted patients). This was the central channel containing the MRI target in 39% of the STN (18% bilaterally). The most frequently noted reasons why another channel than the central channel was chosen for final lead placement were (1) a lower threshold for side effects (54%) and (2) no or a too short trajectory of the STN MER signal (40%) in the central channel. The latter reason correlated with larger 2D (<i>x</i> and <i>y</i>) errors in our stereotactic method. <b><i>Conclusions:</i></b> STN DBS leads were often not implanted in the MRI-planned trajectory or in the trajectory with the longest STN MER signal. Thresholds for side effects during awake test stimulation were decisive for final target selection in the majority of patients.

Longitudinal Assessment of Rotation Angles after Implantation of Directional Deep Brain Stimulation Leads

“…Deep brain stimulation (DBS) as a therapeutic approach to movement disorders such as Parkinson disease (PD), dystonia, and tremor has always relied on neuroimaging for precise lead placement [1]. Still, to date, no generally accepted protocol for lead localization has been established, and most clinicians use imaging fusion of pre- and postoperative cranial computer tomography (CCT) and/or magnetic resonance imaging (MRI) data to confirm the lead location at the attempted site [2].…”

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

“…Thus far, several groups reported good clinical outcomes in patients with Parkinson's disease undergoing STN DBS surgery under general anesthesia [45][46][47]. In our previously mentioned 2020 study employing MRI targeting, three-channel MER, and awake test stimulation, we retrospectively determined the relative contribution of awake test stimulation in STN DBS lead placement by analyzing where final DBS leads were implanted and why these locations were chosen [37]. For final lead placement, the MRI-targeted trajectory was chosen in 39% of STNs (18% of bilaterally implanted patients), the trajectory with the longest STN MER signal in 60% of STNs (38% of bilaterally implanted patients).…”

“…In 2010, we reported how often each of these five MER channels was chosen for final STN DBS lead implantation: the central channel was chosen in 50% of the cases, the anterior channel in 24%, the lateral channel in 10%, the posterior channel in 10%, and the medial channel in 6% [ 35 ]. Because of these results and the finding of a systematic literature review showing that the number of MER penetrations may increase the risk of intracerebral hemorrhage [ 36 ], we reduced the number of MER channels in the years thereafter to three (MRI target, 2 mm anterior and 2 mm lateral channels) and found that 92% of final STN DBS leads were indeed implanted in one of those three channels [ 37 ]. Three-channel instead of five-channel MER thus provides sufficient accuracy to target the dorsolateral STN in the large majority of patients.…”

“…As stated previously, not all MRI sequences properly display the dorsolateral STN, and clinically relevant discrepancies were reported when comparing dorsal STN borders on MRI to the electrophysiological dorsal STN border. Indeed, in our 2020 study no electrophysiological STN signal was found in 5% of the MRI-targeted trajectories, and unexpectedly short STN MER trajectories (2.5 mm or less) were seen in 13% of MRI-targeted channels [ 37 ]. Similarly, Lozano et al reported a 20% mismatch between the expected STN on 1.5-T MRI and the MER findings, with mismatch defined as an STN MER trajectory of less than 4 mm [ 40 ].…”

Methodological Considerations for Neuroimaging in Deep Brain Stimulation of the Subthalamic Nucleus in Parkinson’s Disease Patients

“…There are reports that suggest MER significantly improves DBS outcomes [ 80 ], and that MER fails to show any significant benefit compared to direct targeting [ 81 ]. Moreover, there remains a mismatch of around 20% in the planned target coordinate based on MRI, compared to the actual optimal location identified with MER when using 1.5 and 3 T [ 82 , 83 ]. Further, the use of intra-operative ultra-low field MRI for identification of the test leads during surgery has shown to be as effective as MER in improving post-operative motor symptoms [ 84 ].…”