A Well-Being Well-Check for Neurosurgery: Evidence-Based Suggestions for Our Specialty Based on a Systematic Review.

BACKGROUND: The path through neurosurgery is rigorous. Many neurosurgeons may experience burnout, depression, or suicide throughout training and practice. We review the literature to help foster a culture of awareness and self-care and arm trainees with coping skills to reduce burnout and, thus, suicidality during all phases of their medical careers. METHODS: A systematic search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using 4 databases. 7 studies were included. RESULTS: Overlying themes of interventions were to increase balance, mindfulness, and physical fitness. The most common interventions included in programs were educational and physical activity. We suggest a comprehensive wellness program emphasizing interventions from 4 wellness dimensions-physical, spiritual, mental, and emotional. CONCLUSIONS: Many neurosurgeons experience burnout, leading to a lack of satisfaction and early retirement; this necessitates a discipline-wide acknowledgment of endemic burnout among neurosurgeons. Systemic changes are needed to refine the training process and prioritize physician well-being- this cannot be left to chance.

Acute deep brain stimulation of the paraventricular nucleus of the hypothalamus increases brown adipose tissue thermogenesis in rats.

Brown adipose tissue (BAT) activity is controlled by the sympathetic nervous system. Activation of BAT has shown significant promise in preclinical studies to elicit weight loss. Since the hypothalamic paraventricular nucleus (PVN) contributes to the regulation of BAT thermogenic activity, we sought to determine the effects of electrical stimulation of the PVN as a model of deep brain stimulation (DBS) for increasing BAT sympathetic nerve activity (SNA). The rostral raphe pallidus area (rRPa) was also chosen as a target for DBS since it contains the sympathetic premotor neurons for BAT. Electrical stimulation (100 µA, 100 µs, 100 Hz, for 5 min at a 50 % duty cycle) of the PVN increased BAT SNA and BAT thermogenesis. These effects were prevented by a local nanoinjection of bicuculline, a GABAA receptor antagonist. We suggest that electrical stimulation of the PVN elicited local release of GABA, which inhibited BAT sympathoinhibitory neurons in PVN, thereby releasing a restraint on BAT SNA. Electrical stimulation of the rRPa inhibited BAT thermogenesis and this was prevented by a local nanoinjection of bicuculline, suggesting that local release of GABA suppressed BAT SNA. Electrical stimulation of the PVN activates BAT metabolism via a mechanism that may include activation of local GABAA receptors. These findings contribute to our understanding of the mechanisms underlying the effects of DBS in the regulation of fat metabolism and provide a foundation for further DBS studies targeting hypothalamic circuits regulating BAT thermogenesis as a therapy for obesity.

Identifying the therapeutic zone in globus pallidus deep brain stimulation for Parkinson's disease.

OBJECTIVE: The globus pallidus internus (GPI) has been demonstrated to be an effective surgical target for deep brain stimulation (DBS) treatment in patients with medication-refractory Parkinson's disease (PD). The ability of neurosurgeons to define the area of greatest therapeutic benefit within the globus pallidus (GP) may improve clinical outcomes in these patients. The objective of this study was to determine the best DBS therapeutic implantation site within the GP for effective treatment in PD patients. METHODS: The authors performed a retrospective review of 56 patients who underwent bilateral GP DBS implantation at their institution during the period from January 2015 to January 2020. Each implanted contact was anatomically localized. Patients were followed for stimulation programming for at least 6 months. The authors reviewed preoperative and 6-month postsurgery clinical outcomes based on data from the Unified Parkinson's Disease Rating Scale Part III (UPDRS III), dyskinesia scores, and levodopa equivalent daily dose (LEDD). RESULTS: Of the 112 leads implanted, the therapeutic cathode was most frequently located in the lamina between the GPI external segment (GPIe) and the GP externus (GPE) (n = 40). Other common locations included the GPE (n = 24), the GPIe (n = 15), and the lamina between the GPI internal segment (GPIi) and the GPIe (n = 14). In the majority of patients (73%) a monopolar programming configuration was used. At 6 months postsurgery, UPDRS III off medications (OFF) and on stimulation (ON) scores significantly improved (z = -4.02, p < 0.001), as did postsurgery dyskinesia ON scores (z = -4.08, p < 0.001) and postsurgery LEDD (z = -4.7, p < 0.001). CONCLUSIONS: Though the ventral GP (pallidotomy target) has been a commonly used target for GP DBS, a more dorsolateral target may be more effective for neuromodulation strategies. The assessment of therapeutic contact locations performed in this study showed that the lamina between GPI and GPE used in most patients is the optimal central stimulation target. This information should improve preoperative GP targeting.

The Long-Term Outcome of Radiofrequency Ablation in Multiple Sclerosis-Related Symptomatic Trigeminal Neuralgia.

BACKGROUND: Radiofrequency lesioning (RFL) is used to surgically manage trigeminal neuralgia (TN) secondary to multiple sclerosis (MS). However, the long-term outcome of RFL has not been established. OBJECTIVE: To investigate the long-term clinical outcome of RFL in MS-related TN (symptomatic trigeminal neuralgia [STN]). METHODS: During a 23-yr period, institutional data were available for 51 patients with STN who underwent at least one RFL procedure to treat facial pain. Patient outcome was evaluated at a mean follow-up of 69 mo (95% confidence interval; range 52-86 mo). No pain with no medication (NPNM) was the primary long-term outcome measure. RESULTS: After an initial RFL procedure, immediate pain relief was achieved in 50 patients (98%), and NPNM as assessed at 1, 3, and 6 yr was 86%, 52%, and 22%, respectively. At the last clinical visit after an initial RFL, 23 patients (45%) with pain recurrence underwent repeat RFL; NPNM at 1, 3, and 6 yr after a repeat RFL was 85%, 58%, and 32%, respectively. There was no difference in pain outcome after an initial and repeat RFL ( P = .77). Ten patients with pain recurrence underwent additional RFL procedures. Two patients developed mastication muscle weakness, one patient experienced a corneal abrasion, which resolved with early ophthalmological interventions, and one patient experienced bothersome numbness. CONCLUSION: RFL achieves NPNM status in STN and can be repeated with similar efficacy.

Neurosurgery residency and fellowship education in the United States: 2 decades of system development by the One Neurosurgery Summit organizations.

The purpose of this report is to chronicle a 2-decade period of educational innovation and improvement, as well as governance reform, across the specialty of neurological surgery. Neurological surgery educational and professional governance systems have evolved substantially over the past 2 decades with the goal of improving training outcomes, patient safety, and the quality of US neurosurgical care. Innovations during this period have included the following: creating a consensus national curriculum; standardizing the length and structure of neurosurgical training; introducing educational outcomes milestones and required case minimums; establishing national skills, safety, and professionalism courses; systematically accrediting subspecialty fellowships; expanding professional development for educators; promoting training in research; and coordinating policy and strategy through the cooperation of national stakeholder organizations. A series of education summits held between 2007 and 2009 restructured some aspects of neurosurgical residency training. Since 2010, ongoing meetings of the One Neurosurgery Summit have provided strategic coordination for specialty definition, neurosurgical education, public policy, and governance. The Summit now includes leadership representatives from the Society of Neurological Surgeons, the American Association of Neurological Surgeons, the Congress of Neurological Surgeons, the American Board of Neurological Surgery, the Review Committee for Neurological Surgery of the Accreditation Council for Graduate Medical Education, the American Academy of Neurological Surgery, and the AANS/CNS Joint Washington Committee. Together, these organizations have increased the effectiveness and efficiency of the specialty of neurosurgery in advancing educational best practices, aligning policymaking, and coordinating strategic planning in order to meet the highest standards of professionalism and promote public health.

Hidden Error in Optical Stereotactic Navigation Systems and Strategy to Maximize Accuracy.

BACKGROUND: Optical neuronavigation has been established as a reliable and effective adjunct to many neurosurgical procedures. Operations such as asleep deep brain stimulation (aDBS) benefit from the potential increase in accuracy that these systems offer. Built into these technologies is a degree of tolerated error that may exceed the presumed accuracy resulting in suboptimal outcomes. OBJECTIVE: The objective of this study was to identify an underlying source of error in neuronavigation and determine strategies to maximize accuracy. METHODS: A Medtronic Stealth system (Stealth Station 7 hardware, S8 software, version 3.1.1) was used to simulate an aDBS procedure with the Medtronic Nexframe system. Multiple configurations and orientations of the Nexframe-Nexprobe system components were examined to determine potential sources of, and to quantify navigational error, in the optical navigation system. Virtual entry point and target variations were recorded and analyzed. Finally, off-plan error was recorded with the AxiEM system and visual observation on a phantom head. RESULTS: The most significant source of error was found to be the orientation of the reference marker plate configurations to the camera system, with the presentation of the markers perpendicular to the camera line of site being the most accurate position. Entry point errors ranged between 0.134 ± 0.048 and 1.271 ± 0.0986 mm in a complex, reproducible pattern dependent on the orientation of the Nexprobe reference plate. Target errors ranged between 0.311 ± 0.094 and 2.159 ± 0.190 mm with a similarly complex, repeatable pattern. Representative configurations were tested for physical error at target with errors ranging from 1.2 mm to 1.4 mm. Throughout data acquisition, no orientation was indicated as outside the acceptable tolerance by the Stealth software. CONCLUSIONS: Use of optical neuronavigation is expected to increase in frequency and variety of indications. Successful implementation of this technology depends on understanding the tolerances built into the system. In situations that depend on extremely high precision, surgeons should familiarize themselves with potential sources of error so that systems may be optimized beyond the manufacturer's built-in tolerances. We recommend that surgeons align the navigation reference plate and any optical instrument's reference plate spheres in the plane perpendicular to the line of site of the camera to maximize accuracy.

Verification of the Deep Brain Stimulation Electrode Position Using Intraoperative Electromagnetic Localization.

BACKGROUND: Electromagnetic (EM) localization has typically been used to direct shunt catheters into the ventricle. The objective of this study was to determine if this method of EM tracking could be used in a deep brain stimulation (DBS) electrode cannula to accurately predict the eventual location of the electrode contacts. METHODS: The Medtronic AxiEMTM system was used to generate the cannula tip location directed to the planned target site. Prior to clinical testing, a series of phantom modelling observations were made. RESULTS: Phantom trials (n = 23) demonstrated that the cannula tip could be accurately located at the target site with an error of between 0.331 ± 0.144 and 0.6 ± 0.245 mm, depending on the orientation of the delivery system to the axis of the phantom head. Intraoperative EM localization of the DBS cannula was performed in 84 trajectories in 48 patients. The average difference between the planned target and the EM stylet location at the cannula tip was 1.036 ± 0.543 mm. The average error between the planned target coordinates and the actual target electrode location (by CT) was 1.431 ± 0.607 and 1.145 ± 0.636 mm for the EM stylet location in the cannula (p = 0.00312), indicating that EM localization reflected the position of the target electrode more accurately than the planned target. CONCLUSIONS: EM localization can be used to verify the position of DBS electrodes intraoperatively with a high accuracy.

Utilization of 3D imaging reconstructions and assessment of symptom-free survival after microvascular decompression of the facial nerve in hemifacial spasm.

OBJECTIVE: Hemifacial spasm (HFS), largely caused by neurovascular compression (NVC) of the facial nerve, is a rare condition characterized by paroxysmal, unilateral, involuntary contraction of facial muscles. It has long been suggested that these symptoms are due to compression at the transition zone of the facial nerve. The aim of this study was to examine symptom-free survival and long-term quality of life (QOL) in HFS patients who underwent microvascular decompression (MVD). A secondary aim was to examine the benefit of utilizing fused MRI and MRA post hoc 3D reconstructions to better characterize compression location at the facial nerve root exit zone (fREZ). METHODS: The authors retrospectively analyzed patients with HFS who underwent MVD at a single institution, combined with a modified HFS-7 telephone questionnaire. Kaplan-Meier analysis was used to determine event-free survival, and the Wilcoxon signed-rank test was used to compare pre- and postoperative HFS-7 scores. RESULTS: Thirty-five patients underwent MVD for HFS between 2002 and 2018 with subsequent 3D reconstructions of preoperative images. The telephone questionnaire response rate was 71% (25/35). If patients could not be reached by telephone, then the last clinic follow-up date was recorded and any recurrence noted. Twenty-four patients (69%) were symptom free at longest follow-up. The mean length of follow-up was 2.4 years (1 month to 8 years). The mean symptom-free survival time was 44.9 ± 5.8 months, and the average symptom-control survival was 69.1 ± 4.9 months. Four patients (11%) experienced full recurrence. Median HFS-7 scores were reduced by 18 points after surgery (Z = -4.013, p < 0.0001). Three-dimensional reconstructed images demonstrated that NVC most commonly occurred at the attached segment (74%, 26/35) of the facial nerve within the fREZ and least commonly occurred at the traditionally implicated transition zone (6%, 2/35). CONCLUSIONS: MVD is a safe and effective treatment that significantly improves QOL measures for patients with HFS. The vast majority of patients (31/35, 89%) were symptom free or reported only mild symptoms at longest follow-up. Symptom recurrence, if it occurred, was within the first 2 years of surgery, which has important implications for patient expectations and informed consent. Three-dimensional image reconstruction analysis determined that culprit compression most commonly occurs proximally along the brainstem at the attached segment. The success of this procedure is dependent on recognizing this pattern and decompressing appropriately. Three-dimensional reconstructions were found to provide much clearer characterization of this area than traditional preoperative imaging. Therefore, the authors suggest that use of these reconstructions in the preoperative setting has the potential to help identify appropriate surgical candidates, guide operative planning, and thus improve outcome in patients with HFS.

The Spectrum of Trigeminal Neuralgia Without Neurovascular Compression.

BACKGROUND: In trigeminal neuralgia type 1 (TN1), neurovascular compression (NVC) is often assumed to be the pain initiating mechanism. NVC can be surgically addressed by microvascular decompression (MVD). However, some patients with TN1 present without NVC (WONVC). OBJECTIVE: To characterize and analyze the clinical spectrum of a TN1 patient population WONVC. METHODS: A retrospective chart review of patients presenting with TN1 between 2007 and 2017 was performed. Patients who were potential candidates for MVD surgery underwent high-resolution imaging with 3-dimensional (3D) reconstruction to address the presence, or absence, of NVC. Demographic data about the populations with NVC (WNVC) and WONVC were collected. RESULTS: Of 242 patients with TN1, 32% did not have NVC. Patients WONVC were on average 10.6 yr younger than those WNVC. TN1 onset in patients WONVC was more frequent below 48.7 yr, and the opposite was found in patients WNVC. Compared to patients WNVC, those WONVC were predominantly female (odds ratio 4.8), on average were 4 yr younger at symptom onset (34.7 yr) and 7.8 yr younger at first clinic visit, and had a 3.7 yr shorter symptom duration. CONCLUSION: Patients presenting with TN1 WONVC were predominantly females in their mid-30s with short symptom duration. In the absence of NVC, this subgroup of TN1 patients has limited surgical options, and potentially a longer condition duration that must be managed medically or surgically. This population WONVC might provide insights into the true pathophysiology of TN1.

Natural history of neuromodulation devices and therapies: a patient-centered survival analysis.

OBJECTIVE: Despite rapid development and expansion of neuromodulation technologies, knowledge about device and/or therapy durability remains limited. The aim of this study was to evaluate the long-term rate of hardware and therapeutic failure of implanted devices for several neuromodulation therapies. METHODS: The authors performed a retrospective analysis of patients' device and therapy survival data (Kaplan-Meier survival analysis) for deep brain stimulation (DBS), vagus nerve stimulation (VNS), and spinal cord stimulation (SCS) at a single institution (years 1994-2015). RESULTS: During the study period, 450 patients underwent DBS, 383 VNS, and 128 SCS. For DBS, the 5- and 10-year initial device survival was 87% and 73%, respectively, and therapy survival was 96% and 91%, respectively. For VNS, the 5- and 10-year initial device survival was 90% and 70%, respectively, and therapy survival was 99% and 97%, respectively. For SCS, the 5- and 10-year initial device survival was 50% and 34%, respectively, and therapy survival was 74% and 56%, respectively. The average initial device survival for DBS, VNS, and SCS was 14 years, 14 years, and 8 years while mean therapy survival was 18 years, 18 years, and 12.5 years, respectively. CONCLUSIONS: The authors report, for the first time, comparative device and therapy survival rates out to 15 years for large cohorts of DBS, VNS, and SCS patients. Their results demonstrate higher device and therapy survival rates for DBS and VNS than for SCS. Hardware failures were more common among SCS patients, which may have played a role in the discontinuation of therapy. Higher therapy survival than device survival across all modalities indicates continued therapeutic benefit beyond initial device failures, which is important to emphasize when counseling patients.

Contemporary concepts of pain surgery.

Pain surgery is one of the historic foundations of neurological surgery. The authors present a review of contemporary concepts in surgical pain management, with reference to past successes and failures, what has been learned as a subspecialty over the past 50 years, as well as a vision for current and future practice. This subspecialty confronts problems of cancer pain, nociceptive pain, and neuropathic pain. For noncancer pain, ablative procedures such as dorsal root entry zone lesions and rhizolysis for trigeminal neuralgia (TN) should continue to be practiced. Other procedures, such as medial thalamotomy, have not been proven effective and require continued study. Dorsal rhizotomy, dorsal root ganglionectomy, and neurotomy should probably be abandoned. For cancer pain, cordotomy is an important and underutilized method for pain control. Intrathecal opiate administration via an implantable system remains an important option for cancer pain management. While there are encouraging results in small case series, cingulotomy, hypophysectomy, and mesencephalotomy deserve further detailed analysis. Electrical neuromodulation is a rapidly changing discipline, and new methods such as high-frequency spinal cord stimulation (SCS), burst SCS, and dorsal root ganglion stimulation may or may not prove to be more effective than conventional SCS. Despite a history of failure, deep brain stimulation for pain may yet prove to be an effective therapy for specific pain conditions. Peripheral nerve stimulation for conditions such as occipital neuralgia and trigeminal neuropathic pain remains an option, although the quality of outcomes data is a challenge to these applications. Based on the evidence, motor cortex stimulation should be abandoned. TN is a mainstay of the surgical treatment of pain, particularly as new evidence and insights into TN emerge. Pain surgery will continue to build on this heritage, and restorative procedures will likely find a role in the armamentarium. The challenge for the future will be to acquire higher-level evidence to support the practice of surgical pain management.

Balancing Operative Efficiency and Surgical Education: A Functional Neurosurgery Model.

BACKGROUND: Attending surgeons have dual obligations to deliver high-quality health care and train residents. In modern healthcare, lean principles are increasingly applied to processes preceding and following surgery. However, surgeons have limited data regarding variability and waste during any given operation. OBJECTIVE: To measure variability and waste during the following key functional neurosurgery procedures: retrosigmoid craniectomy (microvascular decompression [MVD] and internal neurolysis) and deep brain stimulation (DBS). Additionally, we correlate variability with residents' self-reported readiness for the surgical steps. The aim is to guide surgeons as they balance operative safety and efficiency with training obligations. METHODS: For each operation (retrosigmoid craniectomy and DBS), a standard workflow, segmenting the operation into components, was defined. We observed a representative sample of operations, timing the components, with a focus on variability. To assess perceptions of safety and risk among surgeons of various training levels, a survey was administered. Survey results were correlated with operative variability, attempting to identify areas for increasing value without compromising trainee experience. RESULTS: A sampling of each operation (n = 36) was observed during the study period. For MVD, craniectomy had the highest mean duration and standard deviation, whereas the MVD itself had the lowest mean duration and standard deviation. For DBS, the segments with largest standard deviation in duration were registration and electrode placement. For many steps of both procedures, there was a statistically significant relationship between increasing level of training and increasing perception of safety. CONCLUSION: This proof-of-concept study introduces an educational and process-improvement tool that can be used to aid surgeons in increasing the efficiency of patient care.

Sex-dependent posterior fossa anatomical differences in trigeminal neuralgia patients with and without neurovascular compression: a volumetric MRI age- and sex-matched case-control study.

OBJECTIVE: The pathophysiology of trigeminal neuralgia (TN) in patients without neurovascular compression (NVC) is not completely understood. The objective of this retrospective study was to evaluate the hypothesis that TN patients without NVC differ from TN patient with NVC with respect to brain anatomy and demographic characteristics. METHODS: Six anatomical brain measurements from high-resolution brain MR images were tabulated; anterior-posterior (AP) prepontine cistern length, cerebellopontine angle (CPA) cistern volume, nerve-to-nerve distance, symptomatic nerve length, pons volume, and posterior fossa volume were assessed on OsiriX. Brain MRI anatomical measurements from 232 patients with either TN type 1 or TN type 2 (TN group) were compared with measurements obtained in 100 age- and sex-matched healthy controls (control group). Two-way ANOVA tests were conducted on the 6 measurements relative to group and NVC status. Bonferroni adjustments were used to correct for multiple comparisons. A nonhierarchical k-means cluster analysis was performed on the TN group using age and posterior fossa volume as independent variables. RESULTS: Within the TN group, females were found to be younger than males and less likely to have NVC. The odds ratio (OR) of females not having NVC compared to males was 2.7 (95% CI 1.3-5.5, p = 0.017). Patients younger than 30 years were much less likely to have NVC compared to older patients (OR 4.9, 95% CI 1.3-18.4, p = 0.017). The mean AP prepontine cistern length and symptomatic nerve length were smaller in the TN group than in the control group (5.3 vs 6.5 mm and 8.7 vs 9.7 mm, respectively; p < 0.001). The posterior fossa volume was significantly smaller in TN patients without NVC compared to those with NVC. A TN group cluster analysis suggested a sex-dependent difference that was not observed in those without NVC. Factorial ANOVA and post hoc testing found that findings in males without NVC were significantly different from those in controls or male TN patients with NVC and similar to those in females (female controls as well as female TN patients with or without NVC). CONCLUSIONS: Posterior fossa volume in males was larger than posterior fossa volume in females. This finding, along with the higher incidence of TN in females, suggests that smaller posterior fossa volume might be an independent factor in the pathophysiology of TN, which warrants further study.

A novel scoring system as a preoperative predictor for pain-free survival after microsurgery for trigeminal neuralgia.

OBJECTIVEPain relief following microvascular decompression (MVD) for trigeminal neuralgia (TN) may be related to pain type, degree of neurovascular conflict, arterial compression, and location of compression. The objective of this study was to construct a predictive pain-free scoring system based on clinical and radiographic factors that can be used to preoperatively prognosticate long-term outcomes for TN patients following surgical intervention (MVD or internal neurolysis [IN]). It was hypothesized that contributing factors would include pain type, presence of an artery or vein, neurovascular conflict severity, and compression location (root entry zone).METHODSAt the authors' institution 275 patients with type 1 or type 2 TN (TN1 or TN2) underwent MVD or IN following preoperative high-resolution brain MRI studies. Outcome data were obtained retrospectively by chart review and/or phone follow-up. Characteristics of neurovascular conflict were obtained from preoperative MRI studies. Factors that resulted in a probability value of < 0.05 on univariate logistic regression analyses were entered into a multivariate Cox regression analysis in a backward stepwise fashion. For the multivariate analysis, significance at the 0.15 level was used. A prognostic system was then devised with 4 possible scores (0, 1, 2, or 3) and pain-free survival analyses conducted.RESULTSUnivariate predictors of pain-free survival were pain type (p = 0.013), presence of any vessel (p = 0.042), and neurovascular compression severity (p = 0.038). Scores of 0, 1, 2, and 3 were found to be significantly different in regard to pain-free survival (log rank, p = 0.005). At 5 and 10 years there were 36%, 43%, 61%, and 69%, and 36%, 43%, 56%, and 67% pain-free survival rates in groups 0, 1, 2, and 3, respectively. While TN2 patients had worse outcomes regardless of score, a subgroup analysis of TN1 patients with higher neurovascular conflict (score of 3) had significantly better outcomes than TN1 patients without severe neurovascular conflict (score of 1) (log rank, p = 0.005). Regardless of pain type, those patients with severe neurovascular conflict were more likely to have arterial compression (99%) compared to those with low neurovascular conflict (p < 0.001).CONCLUSIONSPain-free survival was predicted by a scoring system based on preoperative clinical and radiographic findings. Higher scores predicted significantly better pain relief than lower scores. TN1 patients with severe neurovascular conflict had the best long-term pain-free outcome.

Pain-free survival after vagoglossopharyngeal complex sectioning with or without microvascular decompression in glossopharyngeal neuralgia.

OBJECTIVE: Glossopharyngeal neuralgia (GN) is a rare pain condition in which patients experience paroxysmal, lancinating throat pain. Multiple surgical approaches have been used to treat this condition, including microvascular decompression (MVD), and sectioning of cranial nerve (CN) IX and the upper rootlets of CN X, or a combination of the two. The aim of this study was to examine the long-term quality of life and pain-free survival after MVD and sectioning of the CN X/IX complex. METHODS: A combined retrospective chart review and a quality-of-life telephone survey were performed to collect demographic and long-term outcome data. Quality of life was assessed by means of a questionnaire based on a combination of the Barrow Neurological Institute pain intensity scoring criteria and the Brief Pain Inventory-Facial. Kaplan-Meier analysis was performed to determine pain-free survival. RESULTS: Of 18 patients with GN, 17 underwent sectioning of the CN IX/X complex alone or sectioning and MVD depending on the presence of a compressing vessel. Eleven of 17 patients had compression of CN IX/X by the posterior inferior cerebellar artery, 1 had compression by a vertebral artery, and 5 had no compression. One patient (6%) experienced no immediate pain relief. Fifteen (88%) of 17 patients were pain free at the last follow-up (mean 9.33 years, range 5.16-13 years). One patient (6%) experienced throat pain relapse at 3 months. The median pain-free survival was 7.5 years ± 10.6 months. Nine of 18 patients were contacted by telephone. Of the 17 patients who underwent sectioning of the CN IX/X complex, 13 (77%) patients had short-term complaints: dysphagia (n = 4), hoarseness (n = 4), ipsilateral hearing loss (n = 4), ipsilateral taste loss (n = 2), and dizziness (n = 2) at 2 weeks. Nine patients had persistent side effects at latest follow-up. Eight of 9 telephone respondents reported that they would have the surgery over again. CONCLUSIONS: Sectioning of the CN IX/X complex with or without MVD of the glossopharyngeal nerve is a safe and effective surgical therapy for GN with initial pain freedom in 94% of patients and an excellent long-term pain relief (mean 7.5 years).

Pain-free and pain-controlled survival after sectioning the nervus intermedius in nervus intermedius neuralgia: a single-institution review.

OBJECTIVE: Nervus intermedius neuralgia (NIN) or geniculate neuralgia is a rare facial pain condition consisting of sharp, lancinating pain deep in the ear and can occur alongside trigeminal neuralgia (TN). Studies on the clinical presentation, intraoperative findings, and ultimately postoperative outcomes are extremely limited. The aim of this study was to examine the clinical presentation and surgical findings, and determine pain-free survival after sectioning of the nervus intermedius (NI). METHODS: The authors conducted a retrospective chart review and survey of patients who were diagnosed with NIN at one institution and who underwent neurosurgical interventions. Pain-free survival was determined through chart review and phone interviews using a modified facial pain and quality of life questionnaire and represented as Kaplan-Meier curves. RESULTS: The authors found 15 patients with NIN who underwent microsurgical intervention performed by two surgeons from 2002 to 2016 at a single institution. Fourteen of these patients underwent sectioning of the NI, and 8 of 14 had concomitant TN. Five patients had visible neurovascular compression (NVC) of the NI by the anterior inferior cerebellar artery in most cases where NVC was found. The most common postoperative complaints were dizziness and vertigo, diplopia, ear fullness, tinnitus, and temporary facial nerve palsy. Thirteen of the 14 patients reportedly experienced pain relief immediately after surgery. The mean length of follow-up was 6.41 years (range 8 months to 14.5 years). Overall recurrence of any pain was 42% (6 of 14), and 4 patients (isolated NIN that received NI sectioning alone) reported their pain was the same or worse than before surgery at longest follow-up. The median pain-free survival was 4.82 years ± 14.85 months. The median pain-controlled survival was 6.22 years ± 15.78 months. CONCLUSIONS: In this retrospective review, sectioning of the NI produced no major complications, such as permanent facial weakness or deafness, and was effective for patients when performed in addition to other procedures. After sectioning of the NI, patients experienced 4.8 years pain free and experienced 6.2 years of less pain than before surgery. Alone, sectioning of the NI was not effective. The pathophysiology of NIN is not entirely understood. It appears that neurovascular compression plays only a minor role in the syndrome and there is a high degree of overlap with TN.

Preoptic area cooling increases the sympathetic outflow to brown adipose tissue and brown adipose tissue thermogenesis.

Modest cold exposures are likely to activate autonomic thermogenic mechanisms due to activation of cutaneous thermal afferents, whereas central thermosensitive neurons set the background tone on which this afferent input is effective. In addition, more prolonged or severe cold exposures that overwhelm cold defense mechanisms would directly activate thermosensitive neurons within the central nervous system. Here, we examined the involvement of the canonical brown adipose tissue (BAT) sympathoexcitatory efferent pathway in the response to direct local cooling of the preoptic area (POA) in urethane-chloralose-anesthetized rats. With skin temperature and core body temperature maintained between 36 and 39°C, cooling POA temperature by ~1-4°C evoked increases in BAT sympathetic nerve activity (SNA), BAT temperature, expired CO2, and heart rate. POA cooling-evoked responses were inhibited by nanoinjections of ionotropic glutamate receptor antagonists or the GABAA receptor agonist muscimol into the median POA or by nanoinjections of ionotropic glutamate receptor antagonists into the dorsomedial hypothalamic nucleus (bilaterally) or into the raphe pallidus nucleus. These results demonstrate that direct cooling of the POA can increase BAT SNA and thermogenesis via the canonical BAT sympathoexcitatory efferent pathway, even in the face of warm thermal input from the skin and body core.

Asleep Deep Brain Stimulation Reduces Incidence of Intracranial Air during Electrode Implantation.

BACKGROUND: Asleep deep brain stimulation (aDBS) implantation replaces microelectrode recording for image-guided implantation, shortening the operative time and reducing cerebrospinal fluid egress. This may decrease pneumocephalus, thus decreasing brain shift during implantation. OBJECTIVE: To compare the incidence and volume of pneumocephalus during awake (wkDBS) and aDBS procedures. METHODS: A retrospective review of bilateral DBS cases performed at Oregon Health & Science University from 2009 to 2017 was undertaken. Postimplantation imaging was reviewed to determine the presence and volume of intracranial air and measure cortical brain shift. RESULTS: Among 371 patients, pneumocephalus was noted in 66% of wkDBS and 15.6% of aDBS. The average volume of air was significantly higher in wkDBS than aDBS (8.0 vs. 1.8 mL). Volumes of air greater than 7 mL, which have previously been linked to brain shift, occurred significantly more frequently in wkDBS than aDBS (34 vs 5.6%). wkDBS resulted in significantly larger cortical brain shifts (5.8 vs. 1.2 mm). CONCLUSIONS: We show that aDBS reduces the incidence of intracranial air, larger air volumes, and cortical brain shift. Large volumes of intracranial air have been correlated to shifting of brain structures during DBS procedures, a variable that could impact accuracy of electrode placement.