Combination targeting of subthalamic nucleus and ventral intermediate thalamic nucleus with a single trajectory in deep brain stimulation for tremor-dominant Parkinson's disease.

Deep brain stimulation (DBS) has traditionally been used to target the subthalamic nucleus (STN) or globus pallidus internus (GPi) to treat Parkinson's disease (PD) and the ventral intermediate thalamic nucleus (VIM) to treat essential tremor (ET). Recent case reports have described targeting both the STN and VIM with a single trajectory and electrode to treat patients with tremor-dominant PD, yet outcome data for this procedure remains sparse. Our objective is to determine the safety and efficacy of combination STN-VIM DBS. We conducted a single-center retrospective case series of all patients who underwent combined STN-VIM DBS. Demographic, perioperative, and outcome data, including Unified Parkinson Disease Rating Scale-III (UPDRS) and tremor scores (OFF-medication), and levodopa equivalent daily dose (LEDD), were collected and analyzed. Nineteen patients underwent this procedure. Patients were 89% male and 11% female, with a mean age of 63.6 years. Mean preoperative UPDRS was 24.1, and LEDD was 811.8. At a mean follow-up of 33.8 months, UPDRS and LEDD decreased by an average of 9.2 (38.2%) and 326.3 (40.2%), respectively. Tremor scores decreased by 4.9 (59.0%), and 58% were able to decrease total medication burden. One patient developed transient left-sided weakness, yielding a complication rate of 5.3%. Combined targeting of STN and VIM thalamus via a single frontal trajectory for tremor-dominant Parkinson's Disease results in similar UPDRS outcomes to STN DBS and improved control of tremor symptoms. Larger multicenter studies are necessary to validate this as the optimal DBS target for tremor-dominant PD.

Perioperative Coronavirus Disease 2019 (COVID-19) Incidence and Outcomes in Neurosurgical Patients at Two Tertiary Care Centers in Washington, DC, During a Pandemic: A 6-Month Follow-up.

OBJECTIVE: Coronavirus disease 2019 (COVID-19) continues to affect all aspects of health care delivery, and neurosurgical practices are not immune to its impact. We aimed to evaluate neurosurgical practice patterns as well as the perioperative incidence of COVID-19 in neurosurgical patients and their outcomes. METHODS: A retrospective review of neurosurgical and neurointerventional cases at 2 tertiary centers during the first 3 months of the first peak of COVID-19 pandemic (March 8 to June 8) as well as following 3 months (post-peak pandemic; June 9 to September 9) was performed. Baseline characteristics, perioperative COVID-19 test results, modified Medically Necessary, Time-Sensitive (mMeNTS) score, and outcome measures were compared between COVID-19-positive and-negative patients through bivariate and multivariate analysis. RESULTS: In total, 652 neurosurgical and 217 neurointerventional cases were performed during post-peak pandemic period. Cervical spine, lumbar spine, functional/pain, cranioplasty, and cerebral angiogram cases were significantly increased in the postpandemic period. There was a 2.9% (35/1197) positivity rate for COVID-19 testing overall and 3.6% (13/363) positivity rate postoperatively. Age, mMeNTS score, complications, length of stay, case acuity, American Society of Anesthesiologists status, and disposition were significantly different between COVID-19-positive and-negative patients. CONCLUSIONS: A significant increase in elective case volume during the post-peak pandemic period is feasible with low and acceptable incidence of COVID-19 in neurosurgical patients. COVID-19-positive patients were younger, less likely to undergo elective procedures, had increased length of stay, had more complications, and were discharged to a location other than home. The mMeNTS score plays a role in decision-making for scheduling elective cases.

Case Volumes and Perioperative Coronavirus Disease 2019 Incidence in Neurosurgical Patients During a Pandemic: Experiences at Two Tertiary Care Centers in Washington, DC.

OBJECTIVE: The true incidence of perioperative coronavirus disease 2019 (COVID-19) has not been well elucidated in neurosurgical studies. We reviewed the effects of the pandemic on the neurosurgical case volume to study the incidence of COVID-19 in patients undergoing these procedures during the perioperative period and compared the characteristics and outcomes of this group to those of patients without COVID-19. METHODS: The neurosurgical and neurointerventional procedures at 2 tertiary care centers during the pandemic were reviewed. The case volume, type, and acuity were compared to those during the same period in 2019. The perioperative COVID-19 tests and results were evaluated to obtain the incidence. The baseline characteristics, including a modified Medically Necessary Time Sensitive (mMeNTS) score, and outcome measures were compared between those with and without COVID-19. RESULTS: A total of 405 cases were reviewed, and a significant decrease was found in total spine, cervical spine, lumbar spine, and functional/pain cases. No significant differences were found in the number of cranial or neurointerventional cases. Of the 334 patients tested, 18 (5.4%) had tested positive for COVID-19. Five of these patients were diagnosed postoperatively. The mMeNTS score, complications, and case acuity were significantly different between the patients with and without COVID-19. CONCLUSION: A small, but real, risk exists of perioperative COVID-19 in neurosurgical patients, and those patients have tended to have a greater complication rate. Use of the mMeNTS score might play a role in decision making for scheduling elective cases. Further studies are warranted to develop risk stratification and validate the incidence.

Concurrent Intraventricular and Sacral Spinal Drop Metastasis of Ganglioglioma in an Adult Patient: A Case Report and Review of Literature.

Gangliogliomas are uncommon tumors of the central nervous system and rarely occur in the lateral ventricle or present with drop metastasis. We report a 49-year-old male who presented with a six-week history of left leg pain and numbness. Clinical examination revealed no focal neurological deficits. Magnetic resonance imaging (MRI) demonstrated enhancing nodular lesions in the sacral spine abutting the S2 nerve root. Further imaging of the neuroaxis demonstrated a cystic lesion in the left frontal horn of the lateral ventricle. Gross total surgical resection of the ventricular lesion was performed through a transcortical approach, followed by resection of the sacral spinal drop metastasis in a staged manner. A histopathological analysis revealed the diagnosis of low-grade ganglioglioma. To our knowledge, this is the first reported case of a low-grade intraventricular ganglioglioma presenting with symptoms associated with drop metastasis in an adult patient.

Real-Time Evaluation of Anterior Choroidal Artery Patency During Aneurysm Clipping.

Inadvertent occlusion of the anterior choroidal artery during aneurysm clipping can cause a disabling stroke in minutes. We evaluate the clinical utility of direct cortical motor evoked potential (MEP) monitoring during aneurysm clipping, as a real-time assessment of arterial patency, prior to performing indocyanine green videoangiography.   Direct cortical MEPs were recorded in seven patients undergoing surgery for aneurysms that involved or abutted the anterior choroidal artery. The aneurysms clipped in those seven patients included four anterior choroidal artery aneurysms and six posterior communicating artery aneurysms. Serial MEP recordings were performed during the intradural dissection, aneurysm exposure, and clip placement. A significant change in MEPs after clip placement would prompt immediate inspection and removal or repositioning of the clip. If the clip placement appeared satisfactory and MEP recordings were stable, then an intraoperative indocyanine green videoangiogram was performed to confirm obliteration of the aneurysm and patency of the arteries.  Seven patients underwent successful clipping of anterior choroidal artery aneurysms and posterior communicating artery aneurysms using direct cortical MEP monitoring, with good clinical and radiographic outcomes. In six patients, no changes in MEP amplitudes were observed following permanent clip placement. In one patient, a profound decrease in MEP amplitude occurred 220 seconds after placement of a permanent clip on a large posterior communicating aneurysm. An inspection revealed that the anterior choroidal artery was kinked. The clip was immediately removed, and the MEP signals returned to baseline shortly thereafter. A clip was then optimally placed, and the patient awoke without neurologic deficit.  Direct cortical MEPs are a useful adjunct to standard electrophysiologic monitoring in aneurysm surgery, particularly when the anterior choroidal artery or lenticulostriate arteries are at risk. When these arteries are occluded, infarction may occur before the occlusion is detected by indocyanine green videoangiography or intraoperative angiography. The use of MEPs allows real-time detection of ischemia to subcortical motor pathways.

Afterdischarges during cortical stimulation at different frequencies and intensities.

PURPOSE: The occurrence of unwanted afterdischarges (ADs) impedes cortical stimulation for mapping purposes. We investigated the safety of several stimulation paradigms. METHODS: We compared the incidence of ADs and behavioral responses of two stimulation frequencies (50 and 100 Hz), at two intensities (1 and 0.2 ms pulse widths). RESULTS: Stimulation with 100 Hz was more likely to cause ADs than 50 Hz, and stimulation using 1 ms pulse width was more likely to cause ADs than 0.2 ms. CONCLUSIONS: Stimulation using 50 Hz frequency with a pulse width of 0.2 ms might be safer during cortical mapping.

Basal ganglia neuronal discharge in primary and secondary dystonia in patients undergoing pallidotomy.

OBJECTIVE: Basal ganglia neuronal activity in patients undergoing posteroventral pallidotomy (PVP) for the treatment of primary genetic, secondary, or idiopathic dystonia (DYS) was studied to gain a better understanding of the pathophysiology of DYS. METHODS: Intraoperative neurophysiological data recorded from 15 DYS patients were compared with those from 78 patients with Parkinson's disease (PD) who underwent PVP. RESULTS: Putamen neurons in both DYS and PD patients had low discharge rates. Globus pallidus externa (GPe) and globus pallidus interna (GPi) neurons in DYS patients had significantly lower discharge rates and more irregular discharge patterns than in PD patients. GPe and GPi neurons displayed similar discharge rates and patterns in DYS, whereas in PD, the discharge rate of GPe neurons was lower than that of the GPi neurons. The discharge rate and pattern of GPe and GPi neurons in patients whose DYS was ameliorated by PVP were similar to those in DYS patients who did not benefit from PVP. No significant differences in the rate or pattern of neuronal discharge in patients with DYS of different causes were discernible. PVP was most beneficial in patients with primary genetic DYS. Anesthesia with desflurane depressed the discharge rate of the GPe and GPi neurons, particularly in patients with PD. CONCLUSION: Significant differences in the rates and patterns of discharge of GPe and GPi neurons exist in DYS and PD. The findings are discussed with reference to the current model of the functional connections of the basal ganglia.