Magnetic Resonance-Guided Focused Ultrasound without Anesthesiologist Support.

INTRODUCTION: Magnetic resonance-guided focused ultrasound (MRgFUS) is an effective treatment option for essential tremor (ET) and tremor dominant Parkinson's disease (TDPD), which is often performed with sedation or in the presence of an anesthesiologist in an effort to minimize adverse events and maximize patient comfort. This study explores the safety, feasibility, and tolerability of performing MRgFUS without an anesthesiologist. METHODS: This is a single academic center, retrospective review of 180 ET and TDPD patients who underwent MRgFUS treatment without anesthesiologist support. Patient demographics, intra-procedural treatment parameters, peri-procedural adverse events, and 3-month Clinical Rating Scale for Tremor Part B (CRST-B) scores were compared to MRgFUS studies that utilized varying degrees of anesthesia. RESULTS: There were no anesthesia related adverse events or unsuccessful treatments. There were no early treatment terminations due to patient discomfort, regardless of skull density ratio. 94.6% of patients would repeat the procedure again. The most common side effects during treatment were facial/tongue paresthesia (26.3%), followed by nausea (22.3%), dysarthria (8.6%), and scalp pain (8.0%). No anxiolytic, pain, or antihypertensive medications were administered. The most common early adverse event after MRgFUS procedure was gait imbalance (58.3%). There was a significant reduction of 83.1% (83.4% ET and 80.5% TDPD) of the mean CRST-B scores of the treated hand when comparing 3-month and baseline scores (1.8 vs. 10.9, n = 109, p < 0.0001). CONCLUSION: MRgFUS without intra-procedural anesthesiologist support is a safe, feasible, and well-tolerated option, without an increase in peri-procedural adverse events.

Parkinson Disease and Subthalamic Nucleus Deep Brain Stimulation: Cognitive Effects in GBA Mutation Carriers.

OBJECTIVE: This study was undertaken to compare the rate of change in cognition between glucocerebrosidase (GBA) mutation carriers and noncarriers with and without subthalamic nucleus deep brain stimulation (STN-DBS) in Parkinson disease. METHODS: Clinical and genetic data from 12 datasets were examined. Global cognition was assessed using the Mattis Dementia Rating Scale (MDRS). Subjects were examined for mutations in GBA and categorized as GBA carriers with or without DBS (GBA+DBS+, GBA+DBS-), and noncarriers with or without DBS (GBA-DBS+, GBA-DBS-). GBA mutation carriers were subcategorized according to mutation severity (risk variant, mild, severe). Linear mixed modeling was used to compare rate of change in MDRS scores over time among the groups according to GBA and DBS status and then according to GBA severity and DBS status. RESULTS: Data were available for 366 subjects (58 GBA+DBS+, 82 GBA+DBS-, 98 GBA-DBS+, and 128 GBA-DBS- subjects), who were longitudinally followed (range = 36-60 months after surgery). Using the MDRS, GBA+DBS+ subjects declined on average 2.02 points/yr more than GBA-DBS- subjects (95% confidence interval [CI] = -2.35 to -1.69), 1.71 points/yr more than GBA+DBS- subjects (95% CI = -2.14 to -1.28), and 1.49 points/yr more than GBA-DBS+ subjects (95% CI = -1.80 to -1.18). INTERPRETATION: Although not randomized, this composite analysis suggests that the combined effects of GBA mutations and STN-DBS negatively impact cognition. We advise that DBS candidates be screened for GBA mutations as part of the presurgical decision-making process. We advise that GBA mutation carriers be counseled regarding potential risks associated with STN-DBS so that alternative options may be considered. ANN NEUROL 2022;91:424-435.

Initiating a Magnetic Resonance-Guided Focused Ultrasound Program: Comprehensive Workflow and Lessons Learned from the Initial 116 Cases.

INTRODUCTION: Magnetic resonance-guided focused ultrasound (MRgFUS) represents an incisionless treatment option for essential or parkinsonian tremor. The incisionless nature of this procedure has garnered interest from both patients and providers. As such, an increasing number of centers are initiating new MRgFUS programs, necessitating development of unique workflows to optimize patient care and safety. Herein, we describe establishment of a multi-disciplinary team, workflow processes, and outcomes for a new MRgFUS program. METHODS: This is a single-academic center retrospective review of 116 consecutive patients treated for hand tremor between 2020 and 2022. MRgFUS team members, treatment workflow, and treatment logistics were reviewed and categorized. Tremor severity and adverse events were evaluated at baseline, 3, 6, and 12 months post-MRgFUS with the Clinical Rating Scale for Tremor Part B (CRST-B). Trends in outcome and treatment parameters over time were assessed. Workflow and technical modifications were noted. RESULTS: The procedure, workflow, and team members remained consistent throughout all treatments. Technique modifications were attempted to reduce adverse events. A significant reduction in CRST-B score was achieved at 3 months (84.5%), 6 months (79.8%), and 12 months (72.2%) post-procedure (p < 0.0001). The most common post-procedure adverse events in the acute period (<1 day) were gait imbalance (61.1%), fatigue and/or lethargy (25.0%), dysarthria (23.2%), headache (20.4%), and lip/hand paresthesia (13.9%). By 12 months, the majority of adverse events had resolved with a residual 17.8% reporting gait imbalance, 2.2% dysarthria, and 8.9% lip/hand paresthesia. No significant trends in treatment parameters were found. CONCLUSIONS: We demonstrate the feasibility of establishing an MRgFUS program with a relatively rapid increase in evaluation and treatment of patients while maintaining high standards of safety and quality. While efficacious and durable, adverse events occur and can be permanent in MRgFUS.

Increased Subthalamic Nucleus Deep Brain Stimulation Amplitude Impairs Inhibitory Control of Eye Movements in Parkinson's Disease.

BACKGROUND AND OBJECTIVES: Bilateral subthalamic nucleus deep brain stimulation (STN DBS) in Parkinson's disease (PD) can have detrimental effects on eye movement inhibitory control. To investigate this detrimental effect of bilateral STN DBS, we examined the effects of manipulating STN DBS amplitude on inhibitory control during the antisaccade task. The prosaccade error rate during the antisaccade task, that is, directional errors, was indicative of impaired inhibitory control. We hypothesized that as stimulation amplitude increased, the prosaccade error rate would increase. MATERIALS AND METHODS: Ten participants with bilateral STN DBS completed the antisaccade task on six different stimulation amplitudes (including zero amplitude) after a 12-hour overnight withdrawal from antiparkinsonian medication. RESULTS: We found that the prosaccade error rate increased as stimulation amplitude increased (p < 0.01). Additionally, prosaccade error rate increased as the modeled volume of tissue activated (VTA) and STN overlap decreased, but this relationship depended on stimulation amplitude (p = 0.04). CONCLUSIONS: Our findings suggest that higher stimulation amplitude settings can be modulatory for inhibitory control. Some individual variability in the effect of stimulation amplitude can be explained by active contact location and VTA-STN overlap. Higher stimulation amplitudes are more deleterious if the active contacts fall outside of the STN resulting in a smaller VTA-STN overlap. This is clinically significant as it can inform clinical optimization of STN DBS parameters. Further studies are needed to determine stimulation amplitude effects on other aspects of cognition and whether inhibitory control deficits on the antisaccade task result in a meaningful impact on the quality of life.

Structural connectivity of the human massa intermedia: A probabilistic tractography study.

The role of massa intermedia (MI) is poorly understood in humans. Recent studies suggest its presence may play a role in normal human neurocognitive function while prior studies have shown the absence of MI correlated with psychiatric disorders. There is growing evidence that MI is likely a midline white matter conduit, responsible for interhemispheric connectivity, similar to other midline commissures. MI presence was identified in an unrelated sample using the Human Connectome Project database. MI structural connectivity maps were created and gray matter target regions were identified using probabilistic tractography of the whole brain. Probabilistic tractography revealed an extensive network of connections between MI and limbic, frontal and temporal lobes as well as insula and pericalcarine cortices. Women compared to men had stronger connectivity via their MI. The presented results support the role of MI as a midline commissure with strong connectivity to the amygdala, hippocampus, and entorhinal cortex.

The Medial Subthalamic Nucleus Border as a New Anatomical Reference in Stereotactic Neurosurgery for Parkinson's Disease.

INTRODUCTION: The intersection of Bejjani's line with the well-delineated medial subthalamic nucleus (STN) border on MRI has recently been proposed as an individualized reference in subthalamic deep brain stimulation (DBS) surgery for Parkinson's disease (PD). We, therefore, aimed to investigate the applicability across centers of the medial STN border as a patient-specific reference point in STN DBS for PD and explore anatomical variability between left and right mesencephalic area within patients. Furthermore, we aim to evaluate a recently defined theoretic stimulation "hotspot" in a different center. METHODS: Preoperative 3-Tesla T2 and susceptibility-weighted images (SWI) were used to identify the intersection of Bejjani's line with the medial STN border in left and right mesencephalic area. The average stereotactic coordinates of the center of stimulation relative to the medial STN border were compared with the predefined theoretic stimulation "hotspot." RESULTS: Fifty-four patients provided 108 stereotactic coordinates of medial STN borders on both sequences. Significant difference in means was found in the Y-(anteroposterior) and Z-(dorsoventral) directions (T2 vs. SWI; p < 0.001). Mean coordinates in the Y-(anteroposterior) direction differed significantly between left and right mesencephalic area (T2: p < 0.001; SWI: p = 0.021). Sixty-six DBS leads were placed in 36 patients that had finished stimulation programming, and the average stereotactic coordinates of the center of stimulation relative to the medial STN border on T2 sequences were 3.1 mm lateral, 0.7 mm anterior, and 1.8 mm superior, in proximity of the predefined theoretic stimulation "hotspot." CONCLUSION: The medial STN border is applicable across centers as a reference point for STN DBS surgery for PD and seems suitable in order to account for interindividual and intraindividual anatomical variability if one is aware of the discrepancies between T2-weighted imaging and SWI.

Surgical Treatments of Epilepsy.

Nearly 30% of epilepsy patients are refractory to medical therapy. Surgical management of epilepsy is an increasingly viable option for these patients. Although surgery has historically been used as a palliative option, improvements in technology and outcomes show its potential in certain subsets of patients. This article reviews the two main categories of surgical epilepsy treatment-resective surgery and neuromodulation. Resective surgery includes temporal lobe resections, extratemporal resections, laser interstitial thermal therapy, and disconnection procedures. We discuss the three main types of neuromodulation-vagal nerve stimulation, responsive neurostimulation, and deep brain stimulation for epilepsy. The history and indications are explored for each type of treatment. Given the myriad types of resection and neuromodulation techniques, patient selection is reviewed in detail, with a discussion on which patients are most likely to benefit from different treatment strategies. We also discuss outcomes with examples of the pertinent landmark trials and their results. Finally, complications and surgical technique are reviewed. As new indications emerge and patient selection is refined, surgical management will continue to evolve as an adjuvant therapy for epileptic patients.

Age is but a number when considering epilepsy surgery in older adults.

BACKGROUND: A quarter of patients with newly diagnosed epilepsy are older, yet they are less likely to be offered resective surgery potentially because of clinical bias that they incur increased surgical risks. There are few peer-reviewed case series that address this cohort and their outcomes. OBJECTIVE: In the context of current literature, the objective of this study was to report on all epilepsy surgeries in patients aged 50 years or older from a tertiary care center over 15 years with an average follow-up period of 6 years. METHODS: Patients with epilepsy who underwent surgery between 2001 and 2016 were reviewed retrospectively. Inclusion criteria were age > 50 at surgery, availability of presurgical evaluation data, and minimum one year of follow-up data. We identified 34 patients. Seizure outcome was evaluated using the Engel classification system. RESULTS: Thirty-four patients aged 50 years and older out of 276 underwent epilepsy surgery. Average age at time of surgery was 55 years, and average duration of epilepsy was 30 years. Average length of follow-up was 6 years (1-15 years). Twenty-two out of 34 patients (64%) were seizure-free (Engel class I) at their last follow-up visit. Patients with lesional pathology on neuroimaging were more likely to achieve seizure freedom (p < 0.02). Parameters associated with poorer outcome included extratemporal epileptogenic focus (p = 0.07) and bitemporal interictal epileptiform activity (p = 0.003). CONCLUSION: Our study cohort is one of the largest and most representative outcome studies of this age group, following the cohort for 6 years. Our findings demonstrated that when considering epilepsy surgery in an older adult, their age should not play a determining role in the decision-a finding that is more common in modern literature.

Accuracy of Microelectrode Trajectory Adjustments during DBS Assessed by Intraoperative CT.

BACKGROUND/AIMS: Microelectrode recording (MER)-guided deep brain stimulation (DBS) aims to place the DBS lead in the optimal electrophysiological target. When single-track MER or test stimulation yields suboptimal results, trajectory adjustments are made. The accuracy of these trajectory adjustments is unknown. Intraoperative computed tomography can visualize the microelectrode (ME) and verify ME adjustments. We aimed to determine the accuracy of ME movements in patients undergoing MER-guided DBS. METHODS: Coordinates following three methods of adjustment were compared: (1) those within the default "+" configuration of the ME holder; (2) those involving rotation of the default "+" to the "x" configuration; and (3) those involving head stage adjustments. Radial error and absolute differences between coordinates were determined. RESULTS: 87 ME movements in 59 patients were analyzed. Median (IQR) radial error was 0.59 (0.64) mm. Median (IQR) absolute x and y coordinate errors were 0.29 (0.52) and 0.38 (0.44) mm, respectively. Errors were largest after rotating the multielectrode holder to its "x"-shaped setup. CONCLUSION: ME trajectory adjustments can be made accurately. In a considerable number of cases, errors exceeding 1 mm were found. Adjustments from the "+" setup to the "x" setup are most prone to inaccuracies.

Borders of STN determined by MRI versus the electrophysiological STN. A comparison using intraoperative CT.

BACKGROUND: It is unclear which magnetic resonance imaging (MRI) sequence most accurately corresponds with the electrophysiological subthalamic nucleus (STN) obtained during microelectrode recording (MER, MER-STN). CT/MRI fusion allows for comparison between MER-STN and the STN visualized on preoperative MRI (MRI-STN). OBJECTIVE: To compare dorsal and ventral STN borders as seen on 3-Tesla T2-weighted (T2) and susceptibility weighted images (SWI) with electrophysiological STN borders in deep brain stimulation (DBS) for Parkinson's disease (PD). METHODS: Intraoperative CT (iCT) was performed after each MER track. iCT images were merged with preoperative images using planning software. Dorsal and ventral borders of each track were determined and compared to MRI-STN borders. Differences between borders were calculated. RESULTS: A total of 125 tracks were evaluated in 45 patients. MER-STN started and ended more dorsally than respective dorsal and ventral MRI-STN borders. For dorsal borders, differences were 1.9 ± 1.4 mm (T2) and 2.5 ± 1.8 mm (SWI). For ventral borders, differences were 1.9 ± 1.6 mm (T2) and 2.1 ± 1.8 mm (SWI). CONCLUSIONS: Discrepancies were found comparing borders on T2 and SWI to the electrophysiological STN. The largest border differences were found using SWI. Border differences were considerably larger than errors associated with iCT and fusion techniques. A cautious approach should be taken when relying solely on MR imaging for delineation of both clinically relevant STN borders.

Structural Connectivity of the Human Piriform Cortex: an Exploratory Study.

BACKGROUND AND OBJECTIVES: The piriform cortex (PC) is part of the primary olfactory network in humans. Recent findings suggest that it plays a role in pathophysiology of epilepsy. Therefore, studying its connectivity can further our understanding of seizure propagation in epilepsy. We aimed to explore the structural connectivity of PC using high-quality human connectome project data coupled with segmentation of PC on anatomic MRI. METHODS: Twenty subjects were randomly selected from the human connectome project database, and PC was traced on each hemisphere. Probabilistic whole-brain tractography was then used to visualize PC connectivity. RESULTS: The strongest connectivity was noted between PC and ipsilateral insula in both hemispheres. Specifically, the posterior long gyrus of each insula was predominantly connected to PC. This was followed by connections between PC and basal ganglia as well as orbital frontal cortices. CONCLUSION: The PC has the strongest connectivity with the insula bilaterally. Specifically, the posterior long gyri of insula have the strongest connectivity. This finding may provide additional insight for localizing and treating temporo-insular epilepsy.

Technical Feasibility of Delineating the Thalamic Gustatory Tract Using Tractography.

BACKGROUND AND OBJECTIVES: Magnetic resonance-guided focused ultrasound (MRgFUS) has been increasingly performed in recent years as a minimally invasive treatment of essential tremor and tremor-dominant Parkinson disease. One of the side effects after treatment is dysgeusia. Some centers use tractography to facilitate the treatment planning. However, there have been no reports of identifying gustatory tracts so far. Our aim was to investigate the technical feasibility of isolating and visualizing the gustatory tracts, as well as to explore the relationship between the gustatory tract and the MRgFUS lesion using actual patient data. METHODS: We used 20 randomly selected individuals from the Human Connectome Project database to perform tractography of the gustatory tracts. We defined region of interest as the dorsal region of the brainstem, Brodmann area 43 associated with taste perception, and a sphere with a 3-mm radius centered around the ventral intermediate nucleus in the anterior commissure-posterior commissure plane. We also examined the position of the gustatory tract in relation with other tracts, including the medial lemniscus, the pyramidal tract, and the dentatorubrothalamic tract. In addition, using the data of real patients with essential tremor, we investigated the distance between MRgFUS lesions and the gustatory tract and its association with the development of dysgeusia. RESULTS: We delineated a mean of 15 streamlines of the gustatory tracts per subject in each hemisphere. There was no statistical difference in the localization of the gustatory tracts between the left and right cerebral hemispheres. The gustatory tract was located anteromedial to the medial lemniscus and posteromedial to the dentatorubrothalamic tract in the anterior commissure-posterior commissure plane. The distance from the MRgFUS lesion to the gustatory tract was significantly shorter in the case where dysgeusia occurred compared with nondysgeusia cases (P-value: .0068). CONCLUSION: The thalamic gustatory tracts can be reliably visualized using tractography.

Minimizing pneumocephalus during deep brain stimulation surgery.

BACKGROUND: Deep brain stimulation (DBS) surgery is an effective treatment for movement disorders. Introduction of intracranial air following dura opening in DBS surgery can result in targeting inaccuracy and suboptimal outcomes. We develop and evaluate a simple method to minimize pneumocephalus during DBS surgery. METHODS: A retrospective analysis of prospectively collected data was performed on patients undergoing DBS surgery at our institution from 2014 to 2022. A total of 172 leads placed in 89 patients undergoing awake or asleep DBS surgery were analyzed. Pneumocephalus volume was compared between leads placed with PMT and leads placed with standard dural opening. (112 PMT vs. 60 OPEN). Immediate post-operative high-resolution CT scans were obtained for all leads placed, from which pneumocephalus volume was determined through a semi-automated protocol with ITK-SNAP software. Awake surgery was conducted with the head positioned at 15-30°, asleep surgery was conducted at 0°. RESULTS: PMT reduced pneumocephalus from 11.2 cm3±9.2 to 0.8 cm3±1.8 (P<0.0001) in the first hemisphere and from 7.6 cm3 ± 8.4 to 0.43 cm3 ± 0.9 (P<0.0001) in the second hemisphere. No differences in adverse events were noted between PMT and control cases. Lower rates of post-operative headache were observed in PMT group. CONCLUSION: We present and validate a simple yet efficacious technique to reduce pneumocephalus during DBS surgery.

NIH Toolbox performance of persons with Parkinson's disease according to GBA1 and STN-DBS status.

OBJECTIVE: Mutations in the glucocerebrosidase (GBA1) gene and subthalamic nucleus deep brain stimulation (STN-DBS) are independently associated with cognitive dysfunction in persons with Parkinson's disease (PwP). We hypothesized that PwP with both GBA1 mutations and STN-DBS are at greater risk of cognitive dysfunction than PwP with only GBA1 mutations or STN-DBS, or neither. In this study, we determined the pattern of cognitive dysfunction in PwP based on GBA1 mutation status and STN-DBS treatment. METHODS: PwP who are GBA1 mutation carriers with or without DBS (GBA1+DBS+, GBA1+DBS-), and noncarriers with or without DBS (GBA1-DBS+, GBA1-DBS-) were included. Using the NIH Toolbox, cross-sectional differences in response inhibition, processing speed, and episodic memory were compared using analysis of variance with adjustment for relevant covariates. RESULTS: Data were available for 9 GBA1+DBS+, 14 GBA1+DBS-, 17 GBA1-DBS+, and 26 GBA1-DBS- PwP. In this cross-sectional study, after adjusting for covariates, we found that performance on the Flanker test (measure of response inhibition) was lower in GBA1+DBS+ PwP compared with GBA1-DBS+ PwP (P = 0.030). INTERPRETATION: PwP who carry GBA1 mutations and have STN-DBS have greater impaired response inhibition compared with PwP with STN-DBS but without GBA1 mutations. Longitudinal data, including preoperative scores, are required to definitively determine whether GBA1 mutation carriers respond differently to STN-DBS, particularly in the domain of response inhibition.

Frailty and outcomes after unilateral MRI-guided focused ultrasound thalamotomy for tremor.

OBJECTIVE: Frailty is recognized as an important predictor of neurointerventional outcomes. MRI-guided focused ultrasound (MRgFUS) thalamotomy is a treatment option for patients with refractory essential tremor (ET) and tremor-dominant Parkinson's disease (TdPD). The aim of this study was to evaluate whether frailer MRgFUS thalamotomy patients had worse tremor outcomes or more complications. METHODS: The authors performed a cohort analysis of patients treated with MRgFUS between 2020 and 2023. Inclusion criteria were unilateral MRgFUS thalamotomy for ET or TdPD with available follow-up data (minimum 3-month follow-up). Frailty was assessed using the 11-item modified frailty index (mFI-11), which includes 11 medical comorbidities. Tremor outcomes were assessed using the Clinical Rating Scale for Tremor Part B. Complications assessed included disturbances of sensation, speech and swallowing, balance and gait, and strength. RESULTS: In total, 169 eligible patients were identified, including 135 (79.9%) ET and 34 (20.1%) TdPD patients. Frailty did not result in significant differences in tremor outcomes in the combined (p = 0.833), ET (p = 0.902), or TdPD (p = 0.501) cohort, or in any adverse events at the last follow-up (all p > 0.05). The combined mean follow-up was 10.3 ± 5.8 months (range 3-24 months), with cohort-specific mean follow-ups of 10.8 ± 6.0 months for ET and 8.6 ± 4.6 months for TdPD. Between the ET and TdPD cohorts, no significant differences existed in age, sex, handedness, side treated, skull density ratio, number of sonications, peak and average temperatures, energy delivered, BMI, or American Society of Anesthesiologists classification. For medical comorbidities, only hypertension was significantly different (65.9% ET, 47.1% TdPD; p = 0.043). The ET patients were significantly frailer overall, with 20.7% ET and 35.3% TdPD patients considered robust (mFI-11 score of 0), 14.8% ET and 32.4% TdPD patients prefrail (mFI-11 score of 1), 25.9% ET and 8.8% TdPD patients frail (mFI-11 score of 2), and 38.5% ET and 23.5% TdPD patients severely frail (mFI-11 score ≥ 3) (p = 0.007). CONCLUSIONS: Increasing frailty is not associated with worse outcomes, suggesting that MRgFUS may be appropriate even for frailer patients. ET patients are frailer than TdPD patients selected for MRgFUS.

Benefits of subthalamic nucleus deep brain stimulation on visually-guided saccades depend on stimulation side and classic paradigm in Parkinson's disease.

OBJECTIVE: We aimed to gain further insight into previously reported beneficial effects of subthalamic nucleus deep brain stimulation (STN-DBS) on visually-guided saccades by examining the effects of unilateral compared to bilateral stimulation, paradigm, and target eccentricity on saccades in individuals with Parkinson's disease (PD). METHODS: Eleven participants with PD and STN-DBS completed the visually-guided saccade paradigms with OFF, RIGHT, LEFT, and BOTH stimulation. Rightward saccade performance was evaluated for three paradigms and two target eccentricities. RESULTS: First, we found that BOTH and LEFT increased gain, peak velocity, and duration compared to OFF stimulation. Second, we found that BOTH and LEFT stimulation decreased latency during the gap and step paradigms but had no effect on latency during the overlap paradigm. Third, we found that RIGHT was not different compared to OFF at benefiting rightward saccade performance. CONCLUSIONS: Left unilateral and bilateral stimulation both improve the motor outcomes of rightward visually-guided saccades. Additionally, both improve latency, a cognitive-motor outcome, but only in paradigms when attention does not require disengagement from a present stimulus. SIGNIFICANCE: STN-DBS primarily benefits motor and cognitive-motor aspects of visually-guided saccades related to reflexive attentional shifting, with the latter only evident when the fixation-related attentional system is not engaged.

Efficacy of subcutaneous sumatriptan in postcraniotomy pain and opioid consumption.

OBJECTIVE: Traditional pain management pathways following craniotomy are predicated on opioids. However, narcotics can confound critical neurological examination, contribute to respiratory depression, lower the seizure threshold, and lead to medication habituation, dependence, and/or abuse. Alternative medications to better address postoperative pain while mitigating opioid-related adverse effects remain insufficiently studied. Preliminary studies suggest sumatriptan, a 5-HT (1B/1D) receptor agonist known to regulate dural vasoactivity and inflammation, may moderate pain following trigeminal microvascular decompression and chronic postcraniotomy headache. In this study, the authors evaluated the efficacy of sumatriptan to modulate pain and opioid requirements following craniotomy surgery. METHODS: This was a single academic center, retrospective cohort study of 300 consecutive adult patients who underwent elective craniotomy surgery between 2015 and 2022. Patients were equally divided between a control and a sumatriptan cohort contingent upon administration of 6 mg of subcutaneous sumatriptan within 1 hour of surgery completion and prior to opioid administration. Postoperative opioid consumption at 6, 12, and 24 hours, as well as admission total, inpatient length of stay, and 30-day global reevaluation, were assessed. RESULTS: Three hundred patients were included for analysis. Significant differences were seen in baseline hypertension (p < 0.01), hyperlipemia (p < 0.01), anxiety (p = 0.04), and operative time (p = 0.02). A significant reduction of mean postoperative pain scores at 12 (p = 0.03) and 24 (p < 0.01) hours and total opioid consumption (p = 0.04) was observed in the sumatriptan cohort. Subgroup analysis revealed significantly lower postoperative pain scores at 6 (p = 0.05), 12 (p < 0.01), and 24 (p < 0.01) hours in patients who underwent burr hole placement in the sumatriptan cohort as compared with controls; however, no significant difference in opioid consumption was noted. No adverse events related to sumatriptan administration were noted throughout the study. CONCLUSIONS: Postoperative single-dose subcutaneous sumatriptan following elective craniotomy may reduce pain scores and opioid requirements. Additional studies are needed to better understand nuanced differences in opioid modulation and optimal patient selection.

Rubrospinal activation during asleep subthalamic nucleus deep brain stimulation: a false localizing sign. Illustrative case.

BACKGROUND: Deep brain stimulation (DBS) can be a life-changing intervention for patients with Parkinson's disease (PD), but its success is largely dependent on precise lead placement. The subthalamic nucleus (STN) is one of the most common surgical targets of DBS, but the close anatomical and physiological resemblance of the STN to the mediocaudal red nucleus renders these landmarks difficult to distinguish. OBSERVATIONS: We present an atypical case in which targeted localization of the STN resulted in symptoms pathognomonic of rubrospinal tract (RST) stimulation. A 79-year-old female with a 12-year history of right-hand resting tremor due to medically refractory PD presented for asleep bilateral STN-DBS surgery. Right STN intraoperative testing revealed left hand and elbow flexion contractures, initially suggestive of corticospinal tract activation, despite imaging studies demonstrating reasonable lead placement in the central dorsolateral STN. The lead was moved anteromedially near the medial border of the STN, but stimulation at this location revealed similar but more robust flexor hand and arm contractures, without any extraocular muscle involvement. Thus, activation of the RST was suspected. LESSONS: Isolated activation of the RST is possible during STN-DBS surgery. Its identification can help avoid false localization and suboptimal lead placement.