The relevance of biologically effective dose for pain relief and sensory dysfunction after Gamma Knife radiosurgery for trigeminal neuralgia: an 871-patient multicenter study.

OBJECTIVE: Recent studies have suggested that biologically effective dose (BED) is an important correlate of pain relief and sensory dysfunction after Gamma Knife radiosurgery (GKRS) for trigeminal neuralgia (TN). The goal of this study was to determine if BED is superior to prescription dose in predicting outcomes in TN patients undergoing GKRS as a first procedure. METHODS: This was a retrospective study of 871 patients with type 1 TN from 13 GKRS centers. Patient demographics, pain characteristics, treatment parameters, and outcomes were reviewed. BED was compared with prescription dose and other dosimetric factors for their predictive value. RESULTS: The median age of the patients was 68 years, and 60% were female. Nearly 70% of patients experienced pain in the V2 and/or V3 dermatomes, predominantly on the right side (60%). Most patients had modified BNI Pain Intensity Scale grade IV or V pain (89.2%) and were taking 1 or 2 pain medications (74.1%). The median prescription dose was 80 Gy (range 62.5-95 Gy). The proximal trigeminal nerve was targeted in 77.9% of cases, and the median follow-up was 21 months (range 6-156 months). Initial pain relief (modified BNI Pain Intensity Scale grades I-IIIa) was noted in 81.8% of evaluable patients at a median of 30 days. Of 709 patients who achieved initial pain relief, 42.3% experienced at least one pain recurrence after GKRS at a median of 44 months, with 49.0% of these patients undergoing a second procedure. New-onset facial numbness occurred in 25.3% of patients after a median of 8 months. Age ≥ 63 years was associated with a higher probability of both initial pain relief and maintaining pain relief. A distal target location was associated with a higher probability of initial and long-term pain relief, but also a higher incidence of sensory dysfunction. BED ≥ 2100 Gy2.47 was predictive of pain relief at 30 days and 1 year for the distal target, whereas physical dose ≥ 85 Gy was significant for the proximal target, but the restricted range of BED values in this subgroup could be a confounding factor. A maximum brainstem point dose ≥ 29.5 Gy was associated with a higher probability of bothersome facial numbness. CONCLUSIONS: BED and physical dose were both predictive of pain relief and could be used as treatment planning goals for distal and proximal targets, respectively, while considering maximum brainstem point dose < 29.5 Gy as a potential constraint for bothersome numbness.

Movement disorder Deep brain stimulation Hybridization: Patient and caregiver outcomes.

Background and Objectives: Deep brain stimulation (DBS) is a well-established surgical treatment for certain movement disorders and involves the implantation of brain electrodes connected to implantable pulse generators (IPGs). As more device manufacturers have entered the market, some IPG technology has been designed to be compatible with brain electrodes from other manufacturers, which has facilitated the hybridization of implant technology. The aim of this study was to assess the benefits of hybridization of non-rechargeable, constant voltage IPGs to rechargeable, constant current IPGs. Methods: A list of DBS movement disorder patients who had their non-rechargeable, constant voltage IPGs replaced with rechargeable, constant current IPGs from a different manufacturer was compiled. Structured surveys of these patients, and their caregivers when applicable, were undertaken to determine both patient and caregiver satisfaction in this DBS hybridization strategy. Results: Eighteen patients met inclusion criteria and twelve patients or their caregivers completed the structured survey (67% response rate). Nine patients had Parkinson's disease (75%), three had essential tremor (25%). Nine (75%) were converted from bilateral single-channel IPGs, and three (25%) were converted from a unilateral dual-channel IPGs. Overall, 92% of patients and caregivers surveyed reported improvement or no change in their symptoms, 92% reported a decrease or no change in their medication requirements, and 92% report they are satisfied or very satisfied with their IPG hybridization and would recommend the surgery to similar patients. There were no immediate surgical complications. Conclusion: In this series of movement disorder DBS patients, surgery was safe and patient and caregiver satisfaction were high with a hybridization of non-rechargeable, constant voltage IPGs to rechargeable, constant current IPGs.

Surgical Posture with Microscopic Versus Exoscopic Visualization in Anterior Cervical Procedures.

BACKGROUND: Surgeons sustain deviated postures during procedures even with the use of loupes or an operative microscope. The surgical exoscope is a new intraoperative visualization technology designed to improve surgical ergonomics; however, no objective data exist to say that surgeon posture is significantly improved. This study aimed to quantify the difference in posture during standard anterior cervical spine procedures performed with the aid of an operative microscope versus an exoscope. METHODS: This was a prospective cohort study utilizing a posture-sensing device at the surgeon's cervicothoracic junction. The primary outcome was the proportion of time under scope spent in a deviated posture, defined as greater than 10 degrees of deviation from neutral in the x- and y-axes (flexion/extension and lateral bending) of the surgeon's upper torso. Average deviation from baseline for the x-, y-, and z-axes (flexion/extension, lateral bending, and axial rotation, respectively), as well as the percentage of operative time spent with the visualization aid was also analyzed. RESULTS: Overall, 37 anterior cervical procedures were recorded: 18 were performed with an exoscope and 19 with a microscope. Surgeons spent significantly more time in the deviated posture with the operative microscope than with the exoscope (32% vs. 8% with x-axis >10 deg, P <0.005; 20% vs. 6% with y-axis >10 deg, P <0.05). This is also reflected by the significant differences in the average deviation in the x- and y-axes, while under scope. CONCLUSIONS: Utilizing the exoscope for anterior cervical spine procedures allows surgeons to spend less time in a deviated posture.

Stereoelectroencephalography in the setting of a previously implanted responsive neural stimulation device: illustrative case.

BACKGROUND: Responsive neural stimulation (RNS) is a relatively novel procedure for drug-resistant epilepsy, which involves implantation of a device into the skull and brain. As more devices are implanted, there may be an increasing need to perform intracranial electrocorticography in implant patients with persistent seizures. Given the device location, imaging difficulties with implanted devices, and other technical hurdles, stereoelectroencephalography (SEEG) could be especially challenging. The authors describe the first reported SEEG investigation in a patient with an RNS device, highlighting the technical challenges and clinical data ascertained. OBSERVATIONS: A 41-year-old male with drug-resistant epilepsy presented several years after a local surgeon had placed an RNS device with two electrodes in the bilateral parieto-occipital lobes. Because of inadequate seizure control, the patient was offered a repeat SEEG investigation to characterize his epilepsy better. Although more technically challenging than a traditional SEEG implantation, the SEEG investigation was successfully performed, which led to a confirmation of bilateral hippocampal seizure onset. The patient underwent repositioning of his RNS leads with a significant decrease in his seizure frequency. LESSONS: Concurrent implantation of SEEG electrodes in a functioning RNS device can be safely performed and can augment our understanding of a patient's seizures.

Spinal cord stimulation: A novel approach to pain management in Dercum's disease.

Background: Dercum's Disease (DD) is a rare chronic pain syndrome in which patients experience extreme burning pain associated with subcutaneous lipomatous tissue deposits. These patients may also present with; weakness, psychiatric symptoms, metabolic derangements, sleep disturbance, impaired memory, and easy bruising. Common risk factors for DD include: obesity, Caucasian race, and female sex. The etiology of DD remains under debate while it has proven highly resistant to treatment (i.e., requiring high doses of opioids for adequate pain management). Case Description: A 48-year-old female with DD and a prior spinal cord stimulator (SCS) placed for chronic back pain, presented with recurrent back pain, and increased falling. Surgery to replace her SCS resulted in improvement in her back pain and a decreased incidence of falls. Furthermore, she noticed significant improvement in the burning pain attributed to her subcutaneous nodules; this most markedly occurred at and below the level of stimulator placement. Conclusion: A 48-year-old female with the extremely rare condition, DD experienced dramatic reduction in her pain following the successful revision of her SCS.

Rare case of extracranial chordoid meningioma adjacent to the carotid sheath: illustrative case.

BACKGROUND: Chordoid meningioma is a rare World Health Organization (WHO) grade 2 variant of meningioma with histological features resembling those of a chordoma. This tumor type is known for having an aggressive clinical course with a propensity for local recurrence. Most cases occur within the cranium, more specifically around the cerebral convexities. Although extracranial meningiomas of various subtypes have been documented, extracranial meningioma with a chordoid subtype is an extremely rare entity. OBSERVATIONS: The authors herein report the case of a 51-year-old female who presented with a chief complaint of dysphagia and was found to have a neck mass abutting the carotid sheath. The patient underwent resection and final pathology results revealed a WHO grade 2 chordoid meningioma. LESSONS: This case report demonstrates an atypical case of an extracranial chordoid meningioma adjacent to the carotid sheath. To the authors' knowledge, this is the first reported case of a chordoid meningioma occurring within the soft tissue of the neck.

Systematic Review and Meta-Analysis of Responsive Neurostimulation in Epilepsy.

BACKGROUND: Neuromodulatory implants provide promising alternatives for patients with drug-resistant epilepsy (DRE) in whom resective or ablative surgery is not an option. Responsive neurostimulation (RNS) operates a unique "closed-loop" system of electrocorticography-triggered stimulation for seizure control. A comprehensive review of the current literature would be valuable to guide clinical decision-making regarding RNS. METHODS: Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocols, a systematic PubMed literature review was performed to identify appropriate studies involving patients undergoing RNS for DRE. Full texts of included studies were analyzed and extracted data regarding demographics, seizure reduction rate, responder rate (defined as patients with >50% seizure reduction), and complications were compiled for comprehensive statistical analysis. RESULTS: A total of 313 studies were screened, and 17 studies were included in the final review, representative of 541 patients. Mean seizure reduction rate was 68% (95% confidence interval 61%-76%), and the mean responder rate was 68% (95% confidence interval 60%-75%). Complications occurred in 102 of 541 patients, for a complication rate of 18.9%. A strong publication bias toward greater seizure reduction rate and increased responder rate was demonstrated among included literature. CONCLUSIONS: A meta-analysis of recent RNS for DRE literature demonstrates seizure reduction and responder rates comparable with other neuromodulatory implants for epilepsy, demonstrating both the value of this intervention and the need for further research to delineate the optimal patient populations. This analysis also demonstrates a strong publication bias toward positive primary outcomes, highlighting the limitations of current literature. Currently, RNS data are optimistic for the treatment of DRE but should be interpreted cautiously.

Case Series of Skull Base Meningioma Resection in the Octogenarian Population.

Introduction The geriatric population is the fastest growing segment of the American population, and octogenarians are increasingly seen by neurosurgeons for relatively common lesions such as meningiomas. Unfortunately, providers do not have clear data to guide decision-making regarding these lesions, particularly if they involve the skull base. Current research in outcomes among the elderly looks at a wide range of ages, often anyone older than 65. Previous studies in octogenarians report a wide-range of mortality rates and do not focus on skull base lesions. This paper strives to clarify the experiences and outcomes of octogenarians. Patients and Methods This retrospective series reviews skull base tumor surgeries performed at a single academic institution over the past 15 years in octogenarian patients. Primary endpoint was 30-day mortality; however, potential risk factors, perioperative morbidity, postdischarge disposition, and longer term follow-up were also captured. Multivariate logistic regression was performed to identify relevant perioperative and medical characteristics that increases the risk of adverse events. Results Fourteen patients underwent craniotomies for skull base procedures with an average age of 84.5, with a 14% 30-day mortality rate. One patient required a tracheostomy on discharge and approximately half were able to either go home or rehabilitation after their procedure. On statistical analysis, there were no noted characteristics that predisposed any of the patients to a poorer outcome. Conclusion Octogenarian patients were able to tolerate surgery for skull base meningiomas resection. This outcome data may be used to inform surgical decision and guide conversation with patients and their families.

Bilateral pallidal DBS for blepharospasm: A case report and review of the literature.

Background: Deep brain stimulation (DBS) of the globus pallidus internus (GPi) in the treatment of craniocervical dystonia often requires an extended period of stimulation parameter manipulations. Case Description: We present a patient suffering from debilitating blepharospasm treated with bilateral DBS of the GPi alongside 7 years of stimulation parameter manipulations and a literature review of comparable patients. Conclusion: Our literature review suggests that a patient's specific dystonic symptoms can guide stimulation parameter manipulations. Further research regarding trends in stimulation parameters being used in the field for different dystonic symptoms may expedite the stimulation parameter manipulation process.

Cross-Sectional Analysis of US Health Insurance Payer Policies for Humanitarian Device Exemption Indications for Deep Brain Stimulation.

BACKGROUND: The US Food and Drug Administration (FDA) has granted deep brain stimulation (DBS) approval under the humanitarian device exemption (HDE) pathway for both dystonia and obsessive-compulsive disorder (OCD). However, recent reports from the community of functional neurosurgeons suggest that insurance authorization remains a disproportionate barrier to OCD DBS implantation despite both conditions having similar support from the FDA. This cross-sectional study of health insurance policies quantifies the current payer landscape for these two interventions. OBJECTIVES: The aim of this study was to quantify the current payer policy coverage of DBS under HDE status for OCD as compared to DBS for dystonia for eligible patients in the US insurance market. METHODS: A commercial health insurance policy database was queried for documentation on DBS for dystonia and OCD. Results were individually analyzed for payer policy coverage statements on DBS for either dystonia or OCD and categorized as unique or nonunique policies. Unique policy positions were then coded for the geographic region, whether coverage was offered, and guidelines cited as evidence and justification. RESULTS: From the 80 policies in the database, there were 34 unique policies addressing DBS for either dystonia or OCD representing coverage of all 50 states. Of the 34 unique policies, 3 (9%) covered DBS for OCD, while 32 (94%) covered dystonia. Only 2 policies covered neither intervention. CONCLUSIONS: In spite of similar levels of support from the FDA, DBS for OCD has less support from insurance companies on a national level. This study begins to quantify the disparity noted by functional neurosurgeons in recent literature.

Cerebral metastases of malignant mesothelioma.

Malignant pleural mesothelioma represents a rare etiology of lung cancer metastasis to the brain. Neurologically symptomatic presentations are extremely rare as these metastatic lesions are detected in the late stages of the disease. Despite many highly heterogenous treatment techniques reported in the literature, overall survival is poor. A 72-year-old male with a history of mesothelioma presented with recurrent episodes of altered mental status, confusion and expressive aphasia. Imaging indicated a large hemorrhagic, enhancing lesion in the anterior left frontal lobe resulting in midline shift of 6 mm. He underwent a left frontal craniotomy for resection, after which he had complete resolution of symptoms. The resected mass was metastatic high-grade malignant mesothelioma. On a 1-month follow-up, new lesions in the bilateral frontal lobes were discovered, and despite undergoing adjuvant stereotactic radiosurgery, the right one grew significantly, causing notable mass effect. The patient successfully underwent a right craniotomy for resection.

A Rare Third Ventricular Dermoid Cyst in an Adult With Imaging Characteristics Consistent With a Colloid Cyst.

A 64-year-old male presented with spontaneous intracerebral hemorrhage and obstructive hydrocephalus without evidence of a third ventricular mass in 2019. The patient was lost to follow-up and re-admitted one year later for hydrocephalus secondary to a third ventricular mass. Imaging characteristics were consistent with a colloid cyst, which was the presumptive diagnosis. A transcallosal transchoroidal approach was utilized for cyst resection. The cyst wall was carefully incised, releasing flakey, partially solid contents which were grossly inconsistent with a colloid cyst. Due to the concern of iatrogenic cyst rupture in the setting of unknown diagnosis, the patient was placed on steroids post-operatively. Surgical specimens sent at the time of surgery were consistent with dermoid cyst. We present the first reported case of a third ventricular dermoid cyst in an adult initially misdiagnosed as a colloid cyst based on imaging characteristics.

Headache as a Presenting Symptom of Deep Brain Stimulator Generator Failure.

While a headache can have a wide variety of clinical presentations, it may occasionally be a red flag for underlying pathology that should prompt further investigation. Here, we present a case report demonstrating headache as an uncommon symptom of deep brain stimulation (DBS) device failure and discuss its clinical significance in the rapidly expanding list of current indications of DBS treatment. A 61-year-old female underwent bilateral hypothalamic DBS implantation for refractory morbid obesity. After a successful course involving significant weight loss, the patient began to experience worsening of her chronic headaches, refractory to her existing regiment. On interrogation, her generator was found to be depleted and its subsequent replacement led to a near total resolution of her headaches. This represents one of the few reported instances of headache as a sign of device failure in DBS treatment, thus adding to the wide possibility of headache presentations and their underlying pathology.

A consideration for the utility of the post-operative Oswestry Disability Index for measuring outcomes after sacroiliac joint fusion.

Sacroiliac joint (SIJ) dysfunction and its surgical treatment remain a controversial topic in spine surgery. Determining success after SIJ fusion may be difficult due to preexisting back pain, lumbar fusion (LF), and functional disability. We examine the utility of Oswestry Disability Index (ODI) as a measure of clinical outcomes after minimally invasive SIJ fusion. A retrospective review of 24 patients with at least 12- months follow-up. Patients were divided into two groups based on presence of previous LF. Their post-operative ODI was compared with overall satisfaction, pain reduction, and return to work status. No difference in demographics was found in patients with and without prior LF with 92% of patients reporting lower post-operative pain and 96% being satisfied. Presence of LF did not show any statistically significant differences in pain or satisfaction. However, patient with prior LF reported lower ODI than those without LF at 1-year post-operatively (P=0.015). Postoperative ODI may give a falsely pessimistic impression of outcomes in SIJ fusion patients with prior LF, and its use and limitations should be carefully considered in future studies.

Percutaneous transoral clivoplasty and upper cervical vertebroplasties for multifocal skeletal lymphangiomatosis resulting in complete resolution of pain: case report.

Lymphangiomatosis is a rare congenital disorder that results in multiorgan system lymphatic invasion. Symptoms due to axial skeletal involvement can range from chronic bone pain to severe deformity resulting in radiculopathy, myelopathy, and even paralysis. The authors present a case of lymphangiomatosis of the clivus, C-1, and C-2, resulting in chronic pain. The patient was successfully treated with percutaneous transoral clivoplasty and vertebroplasty, without disease progression or return of symptoms at 2 years.

Animal models of post-traumatic epilepsy.

Post-traumatic epilepsy (PTE) is defined as the development of unprovoked seizures in a delayed fashion after traumatic brain injury (TBI). PTE lies at the intersection of two distinct fields of study, epilepsy and neurotrauma. TBI is associated with a myriad of both focal and diffuse anatomic injuries, and an ideal animal model of epilepsy after TBI must mimic the characteristics of human PTE. The three most commonly used models of TBI are lateral fluid percussion, controlled cortical injury, and weight drop. Much of what is known about PTE has resulted from use of these models. In this review, we describe the most commonly used animal models of TBI with special attention to their advantages and disadvantages with respect to their use as a model of PTE.

A pilot study to evaluate awareness of and attitudes about prenatal and neonatal genetic testing in postpartum African American women.

OBJECTIVE: A pilot study to determine whether prenatal and neonatal sickle cell tests conform to the guidelines established by the American Congress of Obstetricians and Gynecologists and the American Academy of Pediatrics. METHODS: The project was initially structured as a pair of in-person interviews of postpartum women at the University of Chicago, the first collecting medical information and the second surveying the ethical, social, and legal implications (ELSI) of sickle cell trait (SCT). Due to inadequate enrollment, we elected to focus only on the second survey. Descriptive statistics and bivariate analyses were performed. RESULTS: A convenience sample was established from 205 women who had completed surveys of whom 12 (6%) received no prenatal care. Of the 60 women who completed both surveys, 15 (25%) were unsure of their hemoglobinopathy status. Of the 50 results we could verify, 2 women (4%) incorrectly recalled their hemoglobinopathy status. Of the 193 women who received prenatal care and completed the ELSI survey, 47 knew their hemoglobinopathy status from a previous pregnancy and 1 had sickle cell disease. Of the remaining 145 women, 53 (37%) recalled hemoglobinopathy testing during this pregnancy and 44 (30%) were unsure. Only 56 (39%) recalled being told they could refuse testing. Of the 115 women whose infants had newborn screening done prior to the interview, only 51 (44%) recalled discussions with a pediatric provider. CONCLUSION: Despite professional guidelines that stress the importance of education, counseling, and consent for prenatal and neonatal testing, postpartum women do not recall these conversations.