Vagus Nerve Stimulation Modulates Phase-Amplitude Coupling in Thalamic Local Field Potentials.

OBJECTIVE: The antiseizure effects of vagus nerve stimulation (VNS) are thought to be mediated by the modulation of afferent thalamocortical circuitry. Cross-frequency phase-amplitude coupling (PAC) is a mechanism of hierarchical network coordination across multiple spatiotemporal scales. In this study, we leverage local field potential (LFP) recordings from the centromedian (CM) (n = 3) and anterior (ATN) (n = 2) nuclei in five patients with tandem thalamic deep brain stimulation and VNS to study neurophysiological changes in the thalamus in response to VNS. MATERIALS AND METHODS: Bipolar LFP data were recorded from contact pairs spanning target nuclei in VNS "on" and "off" states. RESULTS: Active VNS was associated with increased PAC between theta, alpha, and beta phase and gamma amplitude in CM (q < 0.05). Within the ATN, PAC changes also were observed, although these were less robust. In both nuclei, active VNS also modulated interhemispheric bithalamic functional connectivity. CONCLUSIONS: We report that VNS is associated with enhanced PAC and coordinated interhemispheric interactions within and between thalamic nuclei, respectively. These findings advance understanding of putative neurophysiological effects of acute VNS and contextualize previous animal and human studies showing distributed cortical synchronization after VNS.

Surgery, obstetrics and anaesthesia: a Cambrian explosion for global health.

Our current global health structure has not yet evolved to do what the world needs of it. Despite significant advances in some areas of public health over the past few decades, disparities in health have worsened in many areas. The historical approach of global health governance to health issues has been overwhelmingly led by vertical, single disease efforts. Yet, this structure cannot effectively implement broad-reaching international development goals set forth by the United Nations. The solution requires a rapid evolution of the present health system conceptualisation. As the Cambrian period brought skeletal infrastructure to life on our planet with vertebrates, allowing life to take on new capabilities never before witnessed on earth, so will surgery, obstetrics and anaesthesia provide the much needed healthcare delivery infrastructure that will allow health system strengthening to take global healthcare along a new path. Surgery, anaesthesia and obstetrics form the core foundation upon which the whole of global health is built and serve as the skeletal structure and indicator of robust health systems. Integrating these domains as the backbone of health system strengthening will finally allow global health to stand and support all sectors of healthcare delivery as an equal partner in health.

Global neurosurgery: current and potential impact of neurosurgeons at the World Health Organization and the World Health Assembly. Executive summary of the World Federation of Neurosurgical Societies-World Health Organization Liaison Committee at the 71st World Health Assembly.

Since the creation of the World Health Organization (WHO) in 1948, the annual World Health Assembly (WHA) has been the major forum for discussion, debate, and approval of the global health agenda. As such, it informs the framework for the policies and budgets of many of its Member States. For most of its history, a significant portion of the attention of health ministers and Member States has been given to issues of clean water, vaccination, and communicable diseases. For neurosurgeons, the adoption of WHA Resolution 68.15 changed the global health landscape because the importance of surgical care for universal health coverage was highlighted in the document. This resolution was adopted in 2015, shortly after the publication of The Lancet Commission on Global Surgery Report titled "Global Surgery 2030: evidence and solutions for achieving health, welfare and economic development." Mandating global strengthening of emergency and essential surgical care and anesthesia, this resolution has led to the formation of surgical and anesthesia collaborations that center on WHO and can be facilitated via the WHA. Participation by neurosurgeons has grown dramatically, in part due to the official relations between WHO and the World Federation of Neurosurgical Societies, with the result that global neurosurgery is gaining momentum.

Variability in outcome after elective cerebral aneurysm repair in high-volume academic medical centers.

BACKGROUND AND PURPOSE: Unruptured intracranial aneurysm repair is the most commonly performed procedure for the prevention of hemorrhagic stroke. Despite efforts to regionalize care in high-volume centers, overall results have improved little. This study aims to determine the effectiveness in improving outcomes of previous efforts to regionalize unruptured intracranial aneurysm repair to high-volume centers and to recommend future steps toward that goal. METHODS: Using data obtained via the New York Statewide Planning and Research Cooperative System, this study included all patients admitted to any of the 10 highest volume centers in New York state between 2005 and 2010 with a principal diagnosis of unruptured intracranial aneurysm who were treated either by microsurgical or endovascular repair. Mixed-effects logistic regression was used to determine the degree to which hospital-level and patient-level variables contributed to observed variation in good outcome, defined as discharge to home, between hospitals. RESULTS: Of 3499 patients treated during the study period, 2692 (76.9%) were treated at the 10 highest volume centers, with 2198 (81.6%) experiencing a good outcome. Good outcomes varied widely between centers, with 44.6% to 91.1% of clipped patients and 75.4% to 92.1% of coiled patients discharged home. Mixed-effects logistic regression revealed that procedural volume accounts for 85.8% of the between-hospital variation in outcome. CONCLUSIONS: There is notable interhospital heterogeneity in outcomes among even the largest volume unruptured intracranial aneurysm referral centers. Although further regionalization may be needed, mandatory participation in prospective, adjudicated registries will be necessary to reliably identify factors associated with superior outcomes.

Interactive microsurgical anatomy education using photogrammetry 3D models and an augmented reality cube.

OBJECTIVE: This study sought to assess the use of an augmented reality (AR) tool for neurosurgical anatomical education. METHODS: Three-dimensional models were created using advanced photogrammetry and registered onto a handheld AR foam cube imprinted with scannable quick response codes. A perspective analysis of the cube anatomical system was performed by loading a 3D photogrammetry model over a motorized turntable to analyze changes in the surgical window area according to the horizontal rotation. The use of the cube as an intraoperative reference guide for surgical trainees was tested during cadaveric dissection exercises. Neurosurgery trainees from international programs located in Ankara, Turkey; San Salvador, El Salvador; and Moshi, Tanzania, interacted with and assessed the 3D models and AR cube system and then completed a 17-item graded user experience survey. RESULTS: Seven photogrammetry 3D models were created and imported to the cube. Horizontal turntable rotation of the cube translated to measurable and realistic perspective changes in the surgical window area. The combined 3D models and cube system were used to engage trainees during cadaveric dissections, with satisfactory user experience. Thirty-five individuals (20 from Turkey, 10 from El Salvador, and 5 from Tanzania) agreed that the cube system could enhance the learning experience for neurosurgical anatomy. CONCLUSIONS: The AR cube combines tactile and visual sensations with high-resolution 3D models of cadaveric dissections. Inexpensive and lightweight, the cube can be effectively implemented to allow independent co-visualization of anatomical dissection and can potentially supplement neurosurgical education.

History and Current State of Neurosurgery in the Gambia.

BACKGROUND: Despite global efforts to improve surgical care access, many low- and middle-income countries, especially in neurosurgery, face significant shortages. The Gambia exemplifies this, with only 1 fully qualified neurosurgeon serving its population of 2.5 million people. This scarcity results in higher morbidity and mortality. OBJECTIVE: We aim to document the history and current state of neurosurgery in the Gambia to raise awareness and promote neurosurgery development. METHODS: The study reviews the Gambia's health care system, infrastructure, neurosurgical history, workforce, disease burden, and progress, with information derived from reference sources as well as author experience and interviews with key partners in Gambian health care. RESULTS: Neurosurgery in the Gambia began in the 1970s, facing constraints due to competing health care demands. Significant progress occurred much later in the early 2010s, marked by the initiation of Banjul Neuro Missions and the establishment of a dedicated neurosurgery unit. We report significant progress with neurosurgical interventions in the past few years showcasing the unit's dedication to advancing neurosurgical care in the Gambia. However, challenges persist, including a lack of trained neurosurgeons, equipment shortages such as ventilators and diagnostic imaging. Financial barriers for patients, particularly related to the costs of computer tomography scans, pose significant hurdles, impacting the timely diagnosis and intervention for neurological conditions. CONCLUSIONS: Neurosurgery in the Gambia is progressing, but challenges like equipment scarcity hinder further progress. We emphasize the need for addressing cost barriers, improving infrastructure, and fostering research. Engaging the government and international collaborations are vital for sustained development in Gambian neurosurgery.

Volume-dependent effect of perihaematomal oedema on outcome for spontaneous intracerebral haemorrhages.

INTRODUCTION: It is still unknown whether subsequent perihaematomal oedema (PHE) formation further increases the odds of an unfavourable outcome. METHODS: Demographic, clinical, radiographic and outcome data were prospectively collected in a single large academic centre. A multiple logistic regression model was then developed to determine the effect of admission oedema volume on outcome. RESULTS: 133 patients were analysed in this study. While there was no significant association between relative PHE volume and discharge outcome (p=0.713), a strong relationship was observed between absolute PHE volume and discharge outcome (p=0.009). In a multivariate model incorporating known predictors of outcome, as well as other factors found to be significant in our univariate analysis, absolute PHE volume remained a significant predictor of poor outcome only in patients with intracerebral haemorrhage (ICH) volumes ≤30 cm(3) (OR 1.123, 95% CI 1.021 to 1.273, p=0.034). An increase in absolute PHE volume of 10 cm(3) in these patients was found to increase the odds of poor outcome on discharge by a factor of 3.19. CONCLUSIONS: Our findings suggest that the effect of absolute PHE volume on functional outcome following ICH is dependent on haematoma size, with only patients with smaller haemorrhages exhibiting poorer outcome with worse PHE. Further studies are needed to define the precise role of PHE in driving outcome following ICH.

Management of ruptured brain arteriovenous malformations.

Intracranial arteriovenous malformations (AVMs) are a common cause of stroke in younger patients, and often present as intracerebral hemorrhages (ICH), associated with 10 % to 30 % mortality. Patients who present with a hemorrhage from an AVM should be initially stabilized according to acute management guidelines for ICH. The characteristics of a lesion including its size, location in eloquent tissue, and high-risk features will influence risk of rupture, prognosis, as well as help guide management decisions. Given that rupture is associated with an increased risk of 6 % re-rupture in the year following the initial hemorrhage, versus 1 % to 3 % predicted annual risk in non-ruptured lesions only, definitive treatment is encouraged after ICH stabilization. A rest period of 2 to 6 weeks after hemorrhage is recommended before definitive treatment to avoid disrupting friable parenchyma and the hematoma. Treatment may consist of endovascular embolization, surgical resection, radiosurgery, or a combination of these three interventions based on the lesion.

Predictors of long-term shunt-dependent hydrocephalus in patients with intracerebral hemorrhage requiring emergency cerebrospinal fluid diversion.

OBJECT: Intracerebral hemorrhage (ICH) is frequently complicated by acute hydrocephalus, necessitating emergency CSF diversion with a subset of patients, ultimately requiring long-term treatment via placement of permanent ventricular shunts. It is unclear what factors may predict the need for ventricular shunt placement in this patient population. METHODS: The authors performed a retrospective analysis of a prospective database (ICH Outcomes Project) containing patients with nontraumatic ICH admitted to the neurological ICU at Columbia University Medical Center between January 2009 and September 2011. A multiple logistic regression model was developed to identify independent predictors of shunt-dependent hydrocephalus after ICH. The following variables were included: patient age, admission Glasgow Coma Scale score, temporal horn diameter on admission CT imaging, bicaudate index, admission ICH volume and location, intraventricular hemorrhage volume, Graeb score, LeRoux score, third or fourth ventricle hemorrhage, and intracranial pressure (ICP) and ventriculitis during hospital stay. RESULTS: Of 210 patients prospectively enrolled in the ICH Outcomes Project, 64 required emergency CSF diversion via placement of an external ventricular drain and were included in the final cohort. Thirteen of these patients underwent permanent ventricular CSF shunting prior to discharge. In univariate analysis, only thalamic hemorrhage and elevated ICP were significantly associated with the requirement for permanent CSF diversion, with p values of 0.008 and 0.033, respectively. Each remained significant in a multiple logistic regression model in which both variables were present. CONCLUSIONS: Of patients with ICH requiring emergency CSF diversion, those with persistently elevated ICP and thalamic location of their hemorrhage are at increased odds of developing persistent hydrocephalus, necessitating permanent ventricular shunt placement. These factors may assist in predicting which patients will require permanent CSF diversion and could ultimately lead to improvements in the management of this disorder and the outcome in patients with ICH.

Traumatic brain injury in pediatric patients: evidence for the effectiveness of decompressive surgery.

Traumatic brain injury (TBI) is the current leading cause of death in children over 1 year of age. Adequate management and care of pediatric patients is critical to ensure the best functional outcome in this population. In their controversial trial, Cooper et al. concluded that decompressive craniectomy following TBI did not improve clinical outcome of the analyzed adult population. While the study did not target pediatric populations, the results do raise important and timely clinical questions regarding the effectiveness of decompressive surgery in pediatric patients. There is still a paucity of evidence regarding the effectiveness of this therapy in a pediatric population, and there is an especially noticeable knowledge gap surrounding age-stratified interventions in pediatric trauma. The purposes of this review are to first explore the anatomical variations between pediatric and adult populations in the setting of TBI. Second, the authors assess how these differences between adult and pediatric populations could translate into differences in the impact of decompressive surgery following TBI.

Distal ventriculoperitoneal shunt catheter tightly coiled around the valve in the absence of a subgaleal cerebrospinal fluid collection: illustrative case.

BACKGROUND: Among the known complications of ventriculoperitoneal (VP) shunts, subcutaneous or subgaleal migration of distal catheters is rare. Prior case reports have proposed several risk factors, including inadequate fixation of the shunt device, presence of a large subgaleal space filled with cerebrospinal fluid (CSF), and repetitive flexion/extension movement of the head producing a "windlass effect." Tight coiling of a distal catheter around the valve without a large subgaleal space has not been reported. OBSERVATIONS: The patient was born prematurely and underwent VP shunt placement for posthemorrhagic ventricular dilatation at 3 months of age with reassuring postoperative imaging. At approximately 3 years of age, shunt radiography and head computed tomography unexpectedly showed excess tubing coiled extracranially around the shunt valve. The patient did not exhibit any clinical symptoms of shunt malfunction and underwent an uneventful revision of the VP shunt system. No CSF-filled subgaleal space was observed intraoperatively. LESSONS: Distal catheter migration can occur without the clear presence of a subgaleal CSF collection and symptoms of acute hydrocephalus. Appropriate fixation of the shunt system using nonabsorbable stitches is recommended to prevent catheter migration caused by the windlass effect.

Microsurgical Resection and Stabilization of a Giant Spinal Schwannoma: 2-Dimensional Operative Video.

We illustrate the microsurgical resection of a giant lumbar spinal schwannoma in a 37-yr-old male who presented with worsening low back pain, weakness, and numbness and tingling in the bilateral legs and feet. Lumbar spine imaging demonstrated a large, heterogeneously enhancing intradural mass with notable bony erosion. Given the thinning of the pedicles, large tumor size, and bony remodeling, instrumentation was performed in addition to decompression, with direct stimulation-triggered electromyography and intraoperative neurophysiological monitoring. This video demonstrates the surgical technique for resection and accompanied reconstruction necessary for the management of these giant intradural lesions. Postoperatively, the patient had no complications, with improvement of neurological symptoms at follow-up. Though improved, the patient had some residual numbness at postoperative follow-up visit. The patient consented to the procedure. This video was deemed Institutional Review Board (IRB) exempt by the University of Pennsylvania IRB, as it is considered a case report, which does not require IRB approval or patient consent.

Pediatric multicompartmental trigeminal schwannoma: illustrative case.

BACKGROUND: Trigeminal schwannoma (TS) is an uncommon and histologically benign intracranial lesion that can involve any segment of the fifth cranial nerve. Given its often impressive size at diagnosis and frequent involvement of critical neurovascular structures of the skull base, it represents a challenging entity to treat. Pediatric TS is particularly rare and presents unique challenges. Similarly, tumors with extension into multiple compartments (e.g., middle cranial fossa, posterior cranial fossa, extracranial spaces) are notoriously difficult to treat surgically. Combined or staged surgical approaches are typically required to address them, with radiosurgical treatment as an adjunct. OBSERVATIONS: The authors presented the unusual case of a 9-year-old boy with a large, recurrent multicompartmental TS involving Meckel's cave, the cerebellopontine angle, and the infratemporal fossa. Near-total resection was achieved using a frontotemporal-orbitozygomatic craniotomy with a combined interdural and extradural approach. LESSONS: The case report adds to the current literature on multicompartmental TSs in children and their management. The authors also provided a simplified classification of TS that can be generalized to other skull base tumors. Given a lack of precedent, the authors intended to add to the discussion regarding surgical management of these rare and challenging skull base lesions.

Navigated Ultrasonic Osteotomy to Aid in En Bloc Chordoma Resection via Spondylectomy.

BACKGROUND: Chordomas are rare, locally malignant tumors derived from remnants of the notochord that can manifest anywhere in the spine or base of the skull. Surgical treatment for chordomas of the lumbar spine often fails to achieve successful en bloc resection, which is critical to minimizing recurrence risk. CASE DESCRIPTION: In this case report, the authors describe total en bloc resection of a lumbar vertebral body chordoma via the first documented approach of navigated ultrasonic osteotomy for spondylectomy. The patient is a 43-year-old man with end-stage renal disease, requiring dialysis, secondary to diabetes mellitus. The lesion in question was incidentally discovered in the L5 vertebral body during full body scanning for evaluation for a renal transplant. The lesion was diagnosed as a chordoma via percutaneous coaxial needle biopsy. Allogeneic renal transplant was canceled pending treatment of this newly discovered lesion. A combined, staged approach of L3-pelvis posterior instrumented fusion, L5 laminectomy and spondylectomy, and anterior L5 cage reconstruction with L4-S1 fusion was planned. Intraoperative computed tomography scan was performed and stereotactic osteotomies were planned. Ultrasonic osteotome (SONOPET Ultrasonic Aspirator) was registered as a navigation tool and employed, after verification, to complete the posterior stereotactic osteotomies, with postoperative computed tomography, magnetic resonance imaging, and pathology demonstrating successful en bloc resection. The navigated osteotome provided a critical combination of surgical precision and efficiency intraoperatively. CONCLUSIONS: This approach offers a promising technological adjunct for the treatment of complex spine tumors requiring precise resection and reconstruction.

Penetrating Spinal Column Injuries (pSI): An Institutional Experience with 100 Consecutive Cases in an Urban Trauma Center.

BACKGROUND: Gunshot wound (GSW) injuries are among the leading causes of penetrating spinal column injury (pSI). Patients with pSI often have concurrent polytrauma that complicates management. METHODS: We retrospectively reviewed charts between January 2012 to June 2018 at an urban Level 1 trauma center and analyzed bracing and surgical indications, antibiotic and magnetic resonance imaging (MRI) use, and patient outcomes. RESULTS: We identified 100 patients with pSI with an average age of 27.2 (range, 15-58) years. Five patients had knife injuries and 95 suffered GSW. Polytrauma occurred in 90% of patients with an average of 3.39 bullets per patient (range, 1-23). Fourteen patients underwent either decompressive surgery (n = 8) or decompression and fusion (n = 6). Thirty-five patients were externally braced. A total of 43% of patients presented as American Spinal Injury Association-A compared with 26% who were intact. Although 14 patients received prophylactic antibiotics for retained bullets or durotomies, only 2 patients had postoperative wound infections and 4 had extraspinal infections from retained bullets. All inpatient mortalities (n = 5) were patients with cervical pSI. Thirteen patients with GSW obtained MRI scans without complications. Among our cohort, only 65 patients had follow-up with a median follow-up period of 1.25 (range, 1-60) months. CONCLUSIONS: Management of pSI in urban trauma centers is complex, as these victims routinely have polytrauma that takes precedence. Indications for surgical intervention are narrow and secondary to surgery for polytrauma. External bracing may be overutilized. The efficacy of prophylactic antibiotics remains unclear. MRI can contribute valuable information but is limited by uncertainty regarding bullet compatibility. Lack of follow-up limits the study of this population.

The World Federation of Neurosurgical Societies Young Neurosurgeons Survey (Part I): Demographics, Resources, and Education.

BACKGROUND: Providing a comprehensive and effective neurosurgical service requires adequate numbers of well-trained, resourced, and motivated neurosurgeons. The survey aims to better understand 1) the demographics of young neurosurgeons worldwide; 2) the challenges in training and resources that they face; 3) perceived barriers; and 4) needs for development. METHODS: This was a cross-sectional study in which a widely disseminated online survey (April 2018-November 2019) was used to procure a nonprobabilistic sample from current neurosurgical trainees and those within 10 years of training. Data were grouped by World Bank income classifications and analyzed using χ2 tests because of its categorical nature. RESULTS: There were 1294 respondents, with 953 completed responses included in the analysis. Of respondents, 45.2% were from high-income countries (HICs), 23.2% from upper-middle-income countries, 26.8% lower-middle-income countries, and 4.1% from low-income countries. Most respondents (79.8%) were male, a figure more pronounced in lower-income groups. Neuro-oncology was the most popular in HICs and spinal surgery in all other groups. Although access to computed tomography scanning was near universal (98.64%), magnetic resonance imaging access decreased to 66.67% in low-income countries, compared with 98.61% in HICs. Similar patterns were noted with access to operating microscopes, image guidance systems, and high-speed drills. Of respondents, 71.4% had dedicated time for neurosurgical education. CONCLUSIONS: These data confirm and quantify disparities in the equipment and training opportunities among young neurosurgeons practicing in different income groups. We hope that this study will act as a guide to further understand these differences and target resources to remedy them.

The World Federation of Neurosurgical Societies Young Neurosurgeons Survey (Part II): Barriers to Professional Development and Service Delivery in Neurosurgery.

BACKGROUND: Strengthening health systems requires attention to workforce, training needs, and barriers to service delivery. The World Federation of Neurosurgical Societies Young Neurosurgeons Committee survey sought to identify challenges for residents, fellows, and consultants within 10 years of training. METHODS: An online survey was distributed to various neurosurgical societies, personal contacts, and social media platforms (April-November 2018). Responses were grouped by World Bank income classification into high-income countries (HICs), upper middle-income countries (UMICs), low-middle-income countries (LMICs), and low-income countries (LICs). Descriptive statistical analysis was performed. RESULTS: In total, 953 individuals completed the survey. For service delivery, the limited number of trained neurosurgeons was seen as a barrier for 12.5%, 29.8%, 69.2%, and 23.9% of respondents from HICs, UMICs, LMICs, and LICs, respectively (P < 0.0001). The most reported personal challenge was the lack of opportunities for research (HICs, 34.6%; UMICs, 57.5%; LMICs, 61.6%; and LICs, 61.5%; P = 0.03). Other differences by income class included limited access to advice from experienced/senior colleagues (P < 0.001), neurosurgical journals (P < 0.0001), and textbooks (P = 0.02). Assessing how the World Federation of Neurosurgical Societies could best help young neurosurgeons, the most frequent requests (n = 953; 1673 requests) were research (n = 384), education (n = 296), and subspecialty/fellowship training (n = 232). Skills courses and access to cadaver dissection laboratories were also heavily requested. CONCLUSIONS: Young neurosurgeons perceived that additional neurosurgeons are needed globally, especially in LICs and LMICs, and primarily requested additional resources for research and subspecialty training.

Endoscopic-Assisted Spinal Arachnoiditis Adhesiolysis and Placement of a Spinal Cysto-Subarachnoid Shunt.

BACKGROUND: Spinal arachnoiditis and associated arachnoid adhesions can cause debilitating neurological symptoms due to nerve root and spinal cord compression or tethering. Adhesiolysis using a microscopic approach has traditionally been used for this condition. This procedure has been further refined in recent years with the use of flexible endoscopes. CASE DESCRIPTION: We report the case of a patient with progressive thoracic myelopathy secondary to arachnoid adhesions associated with arachnoiditis. A minimally invasive technique of adhesiolysis and placement of a cysto-arachnoid shunt was performed with the assistance of a flexible endoscope. CONCLUSIONS: The present case report has highlighted the advantages of using a flexible endoscope to treat spinal arachnoiditis adhesiolysis and placement of a cysto-arachnoid shunt, including a smaller skin incision and extended visualization.

Long-term outcomes following deep brain stimulation for Parkinson's disease.

OBJECTIVE: Deep brain stimulation (DBS) is an effective treatment for several movement disorders, including Parkinson's disease (PD). While this treatment has been available for decades, studies on long-term patient outcomes have been limited. Here, the authors examined survival and long-term outcomes of PD patients treated with DBS. METHODS: The authors conducted a retrospective analysis using medical records of their patients to identify the first 400 consecutive patients who underwent DBS implantation at their institution from 1999 to 2007. The medical record was used to obtain baseline demographics and neurological status. The authors performed survival analyses using Kaplan-Meier estimation and multivariate regression using Cox proportional hazards modeling. Telephone surveys were used to determine long-term outcomes. RESULTS: Demographics for the cohort of patients with PD (n = 320) were as follows: mean age of 61 years, 70% male, 27% of patients had at least 1 medical comorbidity (coronary artery disease, congestive heart failure, diabetes mellitus, atrial fibrillation, or deep vein thrombosis). Kaplan-Meier survival analysis on a subset of patients with at least 10 years of follow-up (n = 200) revealed a survival probability of 51% (mean age at death 73 years). Using multivariate regression, the authors found that age at implantation (HR 1.02, p = 0.01) and male sex (HR 1.42, p = 0.02) were predictive of reduced survival. Number of medical comorbidities was not significantly associated with survival (p > 0.5). Telephone surveys were completed by 40 surviving patients (mean age 55.1 ± 6.4 years, 72.5% male, 95% subthalamic nucleus DBS, mean follow-up 13.0 ± 1.7 years). Tremor responded best to DBS (72.5% of patients improved), while other motor symptoms remained stable. Ability to conduct activities of daily living (ADLs) remained stable (dressing, 78% of patients; running errands, 52.5% of patients) or worsened (preparing meals, 50% of patients). Patient satisfaction, however, remained high (92.5% happy with DBS, 95% would recommend DBS, and 75% felt it provided symptom control). CONCLUSIONS: DBS for PD is associated with a 10-year survival rate of 51%. Survey data suggest that while DBS does not halt disease progression in PD, it provides durable symptomatic relief and allows many individuals to maintain ADLs over long-term follow-up greater than 10 years. Furthermore, patient satisfaction with DBS remains high at long-term follow-up.