Early Deformation of Deep Brain Stimulation Electrodes Following Surgical Implantation: Intracranial, Brain, and Electrode Mechanics

Refining Stereotaxic Deep Brain Stimulation Surgery Procedures for Parkinson Disease in Pursuit of Zero Pneumocephalus: 2-Dimensional Operative Video

BACKGROUND AND OBJECTIVES

Deep brain stimulation (DBS) is a well-established intervention for alleviating both motor and nonmotor symptoms of Parkinson disease. However, a common complication of stereotaxic DBS surgery is pneumocephalus, which can compromise electrode accuracy, complicate postoperative assessments, and negatively affect the long-term outcomes of DBS surgery. This report proposes a comprehensive and robust set of recommendations aimed at optimizing DBS surgical protocols to achieve zero pneumocephalus outcomes.

METHODS

A retrospective analysis was undertaken on 138 patients with Parkinson disease who underwent simultaneous bilateral stereotaxic DBS targeting either the subthalamic nucleus or the globus pallidus internus at a single institution. The study compared the pneumocephalus volume and postsurgical electrode tip displacement between the original surgical technique and a refined procedure that incorporated modified supine position, dural puncture, and liquid sealing.

RESULTS

With the implementation of the refined procedure, the volume of pneumocephalus significantly decreased from 14.40 ± 17.00 to 0.32 ± 1.02 mL, with 92.9% of patients showing no visible pneumocephalus or intracranial air less than 1 mL. In addition, the refined procedure was associated with less electrode tip displacement in the postoperative stage.

CONCLUSION

The refined procedure effectively minimized the average pneumocephalus volume to approximately 0, and bilateral DBS electrodes exhibited enhanced stability during the postoperative stage.

Flexible neural probes: a review of the current advantages, drawbacks, and future demands

Brain diseases affect millions of people and have a huge social and economic impact. The use of neural probes for studies in animals has been the main approach to increasing knowledge about neural network functioning. Ultimately, neuroscientists are trying to develop new and more effective therapeutic approaches to treating neurological disorders. The implementation of neural probes with multifunctionalities (electrical, optical, and fluidic interactions) has been increasing in the last few years, leading to the creation of devices with high temporal and spatial resolution. Increasing the applicability of, and elements integrated into, neural probes has also led to the necessity to create flexible interfaces, reducing neural tissue damage during probe implantation and increasing the quality of neural acquisition data. In this paper, we review the fabrication, characterization, and validation of several types of flexible neural probes, exploring the main advantages and drawbacks of these devices. Finally, future developments and applications are covered. Overall, this review aims to present the currently available flexible devices and future appropriate avenues for development as possible guidance for future engineered devices.

Intensity-dependent gamma electrical stimulation regulates microglial activation, reduces beta-amyloid load, and facilitates memory in a mouse model of Alzheimer's disease

BACKGROUND

Gamma sensory stimulation may reduce AD-specific pathology. Yet, the efficacy of alternating electrical current stimulation in animal models of AD is unknown, and prior research has not addressed intensity-dependent effects.

METHODS

The intensity-dependent effect of gamma electrical stimulation (GES) with a sinusoidal alternating current at 40 Hz on Aβ clearance and microglia modulation were assessed in 5xFAD mouse hippocampus and cortex, as well as the behavioral performance of the animals with the Morris Water Maze.

RESULTS

One hour of epidural GES delivered over a month significantly (1) reduced Aβ load in the AD brain, (2) increased microglia cell counts, decreased cell body size, increased length of cellular processes of the Iba1 + cells, and (3) improved behavioral performance (learning & memory). All these effects were most pronounced when a higher stimulation current was applied.

CONCLUSION

The efficacy of GES on the reduction of AD pathology and the intensity-dependent feature provide guidance for the development of this promising therapeutic approach.

Feasibility and Accuracy of Robot-Assisted, Stereotactic Biopsy Using 3-Dimensional Intraoperative Imaging and Frameless Registration Tool

BACKGROUND

Robot-assisted stereotactic biopsy is evolving: 3-dimensional intraoperative imaging tools and new frameless registration systems are spreading.

OBJECTIVE

To investigate the accuracy and effectiveness of a new stereotactic biopsy procedure.

METHODS

Observational, retrospective analysis of consecutive robot-assisted stereotactic biopsies using the Neurolocate (Renishaw) frameless registration system and intraoperative O-Arm (Medtronic) performed at a single institution in adults (2019-2021) and comparison with a historical series from the same institution (2006-2016) not using the Neurolocate nor the O-Arm.

RESULTS

In 100 patients (55% men), 6.2 ± 2.5 (1-14) biopsy samples were obtained at 1.7 ± 0.7 (1-3) biopsy sites. An histomolecular diagnosis was obtained in 96% of cases. The mean duration of the procedure was 59.0 ± 22.3 min. The mean distance between the planned and the actual target was 0.7 ± 0.7 mm. On systematic postoperative computed tomography scans, a hemorrhage ≥10 mm was observed in 8 cases (8%) while pneumocephalus was distant from the biopsy site in 76%. A Karnofsky Performance Status score decrease ≥20 points postoperatively was observed in 4%. The average dose length product was 159.7 ± 63.4 mGy cm. Compared with the historical neurosurgical procedure, this new procedure had similar diagnostic yield (96 vs 98.7%; P = .111) and rate of postoperative disability (4.0 vs 4.2%, P = .914) but was shorter (57.8 ± 22.9 vs 77.8 ± 20.9 min; P < .001) despite older patients.

CONCLUSION

Robot-assisted stereotactic biopsy using the Neurolocate frameless registration system and intraoperative O-Arm is a safe and effective neurosurgical procedure. The accuracy of this robot-assisted surgery supports its effectiveness for daily use in stereotactic neurosurgery.