Pedunculopontine Nucleus Region Deep Brain Stimulation in Parkinson Disease: Surgical Techniques, Side Effects, and Postoperative Imaging

Abstract

The pedunculopontine nucleus (PPN) region has received considerable attention in clinical studies as a target for deep brain stimulation (DBS) in Parkinson disease. These studies have yielded variable results with an overall impression of improvement in falls and freezing in many but not all patients treated. We evaluated the available data on the surgical anatomy and terminology of the PPN region in a companion paper. Here we focus on issues concerning surgical technique, imaging, and early side effects of surgery. The aim of this paper was to gain more insight into the reasoning for choosing specific techniques and to discuss shortcomings of available studies. Our data demonstrate the wide range in almost all fields which were investigated. There are a number of important challenges to be resolved, such as identification of the optimal target, the choice of the surgical approach to optimize electrode placement, the impact on the outcome of specific surgical techniques, the reliability of intraoperative confirmation of the target, and methodological differences in postoperative validation of the electrode position. There is considerable variability both within and across groups, the overall experience with PPN DBS is still limited, and there is a lack of controlled trials. Despite these challenges, the procedure seems to provide benefit to selected patients and appears to be relatively safe. One important limitation in comparing studies from different centers and analyzing outcomes is the great variability in targeting and surgical techniques, as shown in our paper. The challenges we identified will be of relevance when designing future studies to better address several controversial issues. We hope that the data we accumulated may facilitate the development of surgical protocols for PPN DBS.

Pedunculopontine nucleus deep brain stimulation in Parkinson's disease: A clinical review

“…Therefore, some studies have reported the location of PPN stimulation relative to local landmarks. A detailed discussion on the surgical anatomy and targeting is found in our companion papers . The next 2 issues are raised as important for understanding the medical management of PPN DBS.…”

“…A detailed discussion on the surgical anatomy and targeting is found in our companion papers. 17,18 The next 2 issues are raised as important for understanding the medical management of PPN DBS.…”

Estimating Accurate Target Coordinates with Magnetic Resonance Images by Using Multiple Phase-Encoding Directions during Acquisition

“…Many investigators have reported various methods for image acquisition in preparation for DBS surgery. For some structures, such as the pedunculopontine nucleus, there is no consensus on the optimal target site, and therefore it is even more important to devise and introduce targeting methods [3, 4]. …”

A 21‐Year Retrospective Study of the Toronto Western Hospital Deep Brain Stimulation Cohort

“…The risk for mortality was lower in the STN DBS group when compared with other DBS targets. However, because the use of non‐STN DBS targets is frequently a second‐line choice when candidates are not optimal for STN DBS including older age, falls, and freezing, the explanation of lower survival in the non‐STN DBS group is likely affected by selection bias. Of note, post‐DBS psychiatric comorbidity was associated with mortality, most likely indicating the negative impact of antipsychotic drugs including worsening of parkinsonism and cardiovascular disease .…”

“…To gain insights into the pathogenicity of sHTZ, we therefore examined mitochondrial function and Zn 21 metabolism in skin fibroblasts from sHTZ carriers as described in the Supporting Information and elsewhere. 2,3 When oxygen consumption rate was determined (Fig. 1A), sHTZ cells showed a significant reduction in the maximal respiration and the spare respiratory capacity indicative of impaired mitochondrial respiration (Fig.…”