Deep brain stimulation for Parkinson's disease: Surgical issues

Abstract

Numerous factors need to be taken into account when implanting deep brain stimulation (DBS) systems into patients with Parkinson's disease. The surgical procedure itself can be divided into immediate preoperative, intraoperative, and immediate postoperative phases. Preoperative considerations include medication withdrawal issues, stereotactic equipment choices, imaging modalities, and targeting strategy. Intraoperative considerations focus on methods for physiological confirmation of a given target for DBS electrode deployment. Terms such as microelectrode recording, microstimulation, and macrostimulation will be defined to clarify inconsistencies in the literature. Advantages and disadvantages of each technique will be addressed. Furthermore, operative decisions such as staging, choice of electrode and implantable pulse generator, and methods of device fixation will be outlined. Postoperative issues include imaging considerations, including magnetic resonance safety, device-device interactions, and immediate surgical complications pertaining to the DBS procedure. This report outlines answers to a series of questions developed to address all aspects of the DBS surgical procedure and decision-making with a systematic overview of the literature (until mid-2004) and by the expert opinion of the authors. This is a report from the Consensus on Deep Brain Stimulation for Parkinson's Disease, a project commissioned by the Congress of Neurological Surgeons and the Movement Disorder Society. It outlines answers to a series of questions developed to address all surgical aspects of deep brain stimulation.

Stereotactic implantation of deep brain stimulation electrodes: a review of technical systems, methods and emerging tools

“…However, the way in which different clinical centres perform DBS electrode implantations often differs. In general, the procedure can be distinguished according to preoperative planning, surgical procedure and postoperative follow-up [79,103,115] …”

“…Today it has been replaced by CT and MR imaging [103,115]. MRI is the imaging modality of choice to visualise the anatomic targets.…”

“…MRI is the imaging modality of choice to visualise the anatomic targets. The sequence used depends on the chosen target structure: T 1 [22] or proton density imaging [54] is especially used for targeting of the globus pallidus, T 2 imaging for STN targeting [46,103,106], inversion recovery images are also beneficial for direct targeting of GPi and STN [99].…”

“…Following manufacturer guidelines [85] imaging is possible only with a 1.5 Tesla horizontal bore MRI, a transmit/receive head coil and when limiting the average head specific absorption rate (SAR) to 0.1 W/kg or less even if this implicates a lower imaging quality. Otherwise heating, magnetic field interactions or induced stimulation for example can be the consequence [103]. Experiences from MRI of implanted deep brain stimulators on a large patient material have been presented by Larson and colleagues [70].…”

Differences among implanted pulse generator waveforms cause variations in the neural response to deep brain stimulation

“…And, it is well recognized that the therapeutic benefit achieved by DBS is primarily dependent on precise electrode placement and careful clinical selection of stimulation parameters Rezai et al, 2006;Volkmann et al, 2006). However, the details of the stimulation waveform become important when defining correlations between DBS parameter settings, clinical outcomes, and/or experimental threshold measurements.…”