Consensus Review on Strategies to Improve Delivery Across the BBB Including Focused Ultrasound.

Drug delivery to the central nervous system (CNS) has been a major challenge for CNS tumors due to the impermeability of the blood brain barrier (BBB). There have been a multitude of techniques aimed at overcoming the BBB obstacle aimed at utilizing natural transport mechanisms or bypassing the BBB which we review here. Another approach that has generated recent interest in the recently published literature is to use new technologies (Laser Interstitial Thermal Therapy, LITT; or Low Intensity Focused Ultrasound, LIFU) to temporarily increase BBB permeability. This review overviews the advantages, disadvantages, and major advances of each method. LIFU has been a major area of research to allow for chemotherapeutics to cross the BBB which has a particular emphasis in this review. While most of the advances remain in animal studies, there are an increasing number of translational clinical trials which will have results in the next few years.

A Nod for Meckel: A Novel Surgical Position Utilizing Meckel's Cave Anatomy for Percutaneous Glycerol Rhizotomy in Trigeminal Neuralgia.

Objective We aim to describe a novel positioning technique using a specific surgical table to achieve the optimal angle during percutaneous glycerol rhizotomy (PGR) for trigeminal neuralgia (TN). Design This is a descriptive and photographic analysis of successful cases for future implementation. Setting This study was conducted at a single-institution, academic center. Participants The participants were adult patients with TN who underwent PGR and provided consent for publication. Main Outcome Measures Primary outcomes of this study were TN symptomatic relief and surgical complications. Results The use of a beach chair sliding headboard surgical table for PGR is plausible and ensures precise and immobile head flexion for 1 hour postglycerol injection. There were no intraoperative or postoperative complications. All patients achieved successful reduction of TN symptoms. Conclusions Utilizing this new method of intraoperative navigation with a unique surgical table in the upright position, surgeons may achieve precise head adjustments post-PGR. Head flexion has been postulated as a means of ensuring glycerol containment in Meckel's cave. This method can help standardize this procedure for future systematic studies on the importance of head positioning post-PGR.

Improvement in Hearing Loss Following Posterior Fossa Arachnoid Cyst Fenestration: A Case Study.

Arachnoid cysts are abnormal intradural collections of cerebrospinal fluid. For posterior fossa arachnoid cysts (PFACs), symptoms vary greatly, often relating to cranial nerve impingement and/or hydrocephalus. Literature on long-term symptomatic and radiographic follow-up of PFACs is lacking. This case study describes a 32-year-old man who presented with headaches and left-sided hearing loss and was found to have a large left-sided cerebellopontine angle arachnoid cyst with syrinx and ventriculomegaly. After PFAC fenestration and excision, his headaches resolved and his hearing markedly improved. At the one-year postoperative evaluation, symptom improvement persisted, and MRI demonstrated a stable decreased cyst and near-complete resolution of his syrinx.

Knowledge Review of Spinal Deformity and the Need for Fusion and Fixation following Treatment for Spinal Tumors among the Pediatric Age Group.

BACKGROUND: Spinal tumors are rare pathology in the pediatric population. The tumors can be classified as extradural, intradural extramedullary, or intramedullary. Any of the spinal tumors can eventually lead to spinal deformity. The progressive spinal deformity can be part of the initial presentation or evolve on long follow-up, even years after the initial intervention and treatment. SUMMARY: Management of spinal deformity associated with spinal tumors in children is not well defined. Patients with progressive symptoms and even neurological deficits need correction for their deformity when diagnosed. Patients that do not have pain or related neurological deficits should be evaluated for the severity of their deformity and followed long-term. Special consideration is needed for young patients who need multilevel surgery or have deformity at presentation. KEY MESSAGES: When considering the need for instrumentation and fusion, the surgeon should consider the age of the patient, expected future growth of the spine, neurologic status, extent of initial deformity, and the number of vertebral levels involved by tumor. Providers should also consider how surgery may fix or prevent deformity, especially when instrumentation can affect imaging at follow-up.

Spontaneous resolution of cerebral arteriovenous malformation after liver transplant: illustrative case.

BACKGROUND: Cerebral arteriovenous malformations (AVMs) have historically been considered congenital lesions with treatment options including surgery, radiation therapy, and observation. Spontaneous resolution of cerebral AVMs remains an exceedingly rare event with poorly understood pathophysiology. MATERIALS AND METHODS: Herein we report a retrospective case review of a 28-year-old man with alcoholic cirrhosis who presented with a seizure 3 weeks after liver transplantation. Neuroimaging confirmed the presence of a Spetzler-Martin grade 2 AVM in the right frontal lobe. Due to the recent liver transplantation, treatment was deferred at the time of initial diagnosis and the patient was observed for a course of 1 year. Follow-up imaging 1 year later showed resolution of the AVM, confirmed by a catheter angiogram. CONCLUSION: Spontaneous resolution of cerebral AVMs is a rare event. Treatment of chronic liver disease resulted in the normalization of angiogenic factors that likely led to AVM resolution. This case provides valuable insight into the vital role of angiogenesis in the natural history of AVMs.

Sacroiliac joint arthropathy in adult spinal deformity patients with long constructs to the pelvis.

OBJECTIVE: Sacroiliac joint (SIJ) arthropathy is an increasingly recognized problem in adult spinal deformity patients undergoing long construct surgery. S2-alar-iliac (S2AI) screw instrumentation is thought to reduce morbidity from pelvic fixation in these patients. The goal of this study is to assess the overall incidence of SIJ arthropathy in patients with long constructs to the pelvis as well as compare SIJ outcomes of partially threaded (PT) versus fully threaded (FT) S2AI screws. METHODS: Data of eligible patients were collected from a prospectively maintained database with retrospective review of electronic records at an academic institution between 2016 and 2019. RESULTS: 65 consecutive patients who underwent S2AI screw instrumentation (40 in PT group, 25 in FT group) were enrolled. The rate of postoperative SIJ pain was higher in the PT (52.5 %) compared to FT (32 %) group. There was a significantly shorter time-to-pain development in the PT compared to FT group (11.8 versus 20.1 months, respectively). Of those who developed SIJ pain in the PT group, the pain worsened in 80.9 % versus only 25 % of those in the FT group despite conservative treatment. Cox regression found the PT group more likely to develop SIJ pain at any point during follow-up compared to the FT group (Hazard Ratio = 7.308). SIJ fusion was not detected on imaging of any patient during follow-up. CONCLUSION: FT S2AI screws are associated with better SIJ outcomes compared to PT screws. However, our data suggest that S2AI screw instrumentation is not sufficient to achieve fusion or prevent development of SIJ pain. Concurrent SIJ fusion may be necessary in patients with long constructs to prevent SIJ arthropathy.

Teflon versus Ivalon in Microvascular Decompression for Trigeminal Neuralgia: A 2-Center 10-Year Comparison.

BACKGROUND: Trigeminal neuralgia features jolts of pain along the distribution of the trigeminal nerve. If patients fail conservative management, microvascular decompression (MVD) is typically the next step in treatment. MVD consists of implanting a separating material, often Teflon, between the nerve and compressive lesions. A review found similar success and complication rates between Teflon and Ivalon, another commonly used material. The aim of this study was to analyze outcomes and complications associated with Teflon and Ivalon in MVD. METHODS: We conducted a 2-center retrospective cohort study of trigeminal neuralgia treated with MVD between 2005 and 2019. Patients with no postoperative follow-up were excluded. Postoperative pain was graded using the Barrow Neurological Institute (BNI) pain intensity score. Relapse was defined as a BNI score of 4-5 during follow-up after initial pain improvement or an initial BNI score of 1-3. RESULTS: The study included 221 MVD procedures in 219 patients. Ivalon was implanted in 121 procedures, and Teflon was implanted in 100 procedures. Multivariate analysis found that implant type had no effect on final BNI score (P = 0.305). Relapse rates were similar at 5- and 10-year follow-up (5-year: Ivalon 10.7%, Teflon 18.0%, P = 0.112; 10-year: Ivalon 11.6%, Teflon 19.0%, P = 0.123). There was no difference in postoperative immediate facial numbness (P = 0.125). Postoperative hearing difficulty was higher in the Ivalon cohort (8.4% vs. 1.0%; P = 0.016). CONCLUSIONS: We found no significant difference in final BNI score or risk of relapse between Ivalon and Teflon. Complications were similar, although Ivalon was more associated with temporary postoperative hearing loss.

The Return Back to Typical Practice from the "Battle Plan" of the Coronavirus Disease 2019 (COVID-19) Pandemic: A Comparative Study.

BACKGROUND: Every aspect of the medical field has been heavily affected by the coronavirus disease 2019 (COVID-19) pandemic, and neurosurgical services are no exception. Several departments have reported their experiences and protocols to provide insights for others impacted. The goals of this study are to report the load and variety of neurosurgical cases and clinic visits after discontinuing the COVID-19 Battle Plan at an academic tertiary care referral center to provide insights for other departments going through the same transition. METHODS: The clinical data of all patients who underwent a neurosurgical intervention between May 4, 2020, and June 4, 2020 were obtained from a prospectively maintained database. Data of the control group were retrospectively collected from the medical records to compare the types of surgeries/interventions and clinic visits performed by the same neurosurgical service before the COVID-19 pandemic started. RESULTS: One hundred sixty-one patients underwent neurosurgical interventions, and seven-hundred one patients were seen in clinic appointments, in the 4-week period following easing back from our COVID-19 "Battle Plan." Discontinuing the "Battle Plan" resulted in increases in case load to above-average practice after a week but a continued decrease in clinic appointments throughout the 4 weeks compared with average practice. CONCLUSIONS: As policy-shaping crises like pandemics abate, easing back to "typical" practice can be completed effectively by appropriately allocating resources. This can be accomplished by anticipating increases in neurosurgical volume, specifically in the functional/epilepsy and brain tumor subspecialties, as well as continued decreases in neurosurgical clinic volume, specifically in elective spine.

Teflon™ or Ivalon®: a scoping review of implants used in microvascular decompression for trigeminal neuralgia.

BACKGROUND: Trigeminal neuralgia (TN) is characterized by jolts of pain along the distribution of the trigeminal nerve. If patients fail conservative management, microvascular decompression (MVD) is the next step in treatment. MVD is largely done by placing implant pads between the nerve and compressing vessels. We conducted a literature review to assess effectiveness and safety of Teflon™ and Ivalon® sponges for treatment of TN with MVD. METHODS: In January 2019, PubMed was searched for manuscripts published in English using permutations of "Microvascular decompression", "Teflon", "Ivalon", "Granuloma", "Polytetrafluoroethylene", "Trigeminal Neuralgia", and "Exploration". Success and relapse rates, causes of relapse, and complication rates were analyzed. We analyzed for relationships with ANCOVA at an alpha threshold of .05. RESULTS: Thirty-six studies representing 4273 patients fit inclusion criteria. Twenty-five dealt with initial MVD, 12 with re-do MVD. Initial MVD initial success rates were 85% in patients receiving Teflon™ (57-100%*) and 91% in patients receiving Ivalon® (79-100%*). Recurrence rates were 12% in Teflon™ patients (0*-30%) and 9.1% in Ivalon® patients (0*-19%). In patients with relapses, implants were the cause in 49% of Teflon™ patients (0*-100%*) and 50% of Ivalon® patients (0*-100%*). Complication rates for patients receiving Teflon™ were 12% (0*-34%) and 19% for patients receiving Ivalon® (0*-40%). CONCLUSION: Teflon™ and Ivalon® are two materials used in MVD for TN. It is an effective treatment with long-term symptom relief and recurrence rates of 1-5% each year. Ivalon® has been used less than Teflon™ though is associated with similar success rates and similar complication rates.

Phantosmia and Dysgeusia following Endoscopic Transcribriform Approaches to Olfactory Groove Meningiomas.

The endoscopic, endonasal transcribriform approach (EETA) is an important technique used to directly access the anterior skull base and is increasingly being used in the management of olfactory groove meningiomas (OGMs). As this approach requires removal of the cribriform plate and olfactory epithelium en route to the tumor, patients are anosmic postoperatively. Here, we report the development of phantosmia and dysgeusia in two patients who underwent EETAs for OGMs, which has not yet been reported in the literature. We hypothesize that phantosmia and dysgeusia may result from aberrant neuronal signals or misinterpretation centrally from the remaining distal portions of the olfactory and taste pathways. Since EETAs are newer than traditional open craniotomy-based techniques, reporting these outcomes will be important to appropriately counsel patients preoperatively.

Vascularized Fibular Strut Autografts in Spinal Reconstruction after Resection of Vertebral Chordoma or Chondrosarcoma: A Retrospective Series.

BACKGROUND: Margin-free en bloc resection is the best medical practice for primary vertebral chordoma and chondrosarcoma. Spinal reconstruction following total spondylectomy requires reconstructive interbody graft (allograft, devascularized autograft, vascularized autograft, or cage constructs) and instrumentation. An important consideration when choosing grafts and instrumentation is the durability and the long-term success of the fusion without subsidence. OBJECTIVE: To evaluate the potential use of vascularized fibular autograft as a reconstructive strategy after en bloc resection. METHODS: We present a series of 16 patients who underwent spondylectomy for primary vertebral chordoma or chondrosarcoma with reconstruction using a vascularized fibular autograft and anterior/posterior instrumentation between January 2011 and April 2014. We report postoperative neurological outcome, 6-mo rates of fusion and graft subsidence, and other complications. RESULTS: Two patients passed away prior to 6-mo follow-up, and 1 patient was lost to follow-up. The mean follow-up time for the remaining 13 patients was 32 mo. Of these patients, 9 (69%) had evidence of fusion on the 6-mo follow-up computed tomography (CT) scan. Of the 4 patients who did not fuse, 2 had undergone surgery for new tumor diagnoses, 1 for hardware failure, and 1 for graft nonunion. Two patients (15%) had eventual graft subsidence along with hardware failure. CONCLUSIONS: Vascularized fibular strut grafts are a viable method for reconstruction following spondylectomy. We present the largest series of patients to date utilizing this technique. Further comparative studies examining vascularized grafts vs nonvascularized grafts or metallic cage constructs will be important in choosing the best reconstructive strategy.

Spinal cord glioblastoma: 25years of experience from a single institution.

Accounting for less than 0.2% of all glioblastomas, high grade gliomas of the spinal cord are very rare. Here, we discuss our approach to managing patients with high grade spinal cord glioma and review the literature on the subject. Six patients with high grade spinal cord gliomas who presented to our institution between 1990 and 2015 were reviewed. Each patient underwent subtotal surgical resection, with a subset receiving adjuvant chemotherapy and radiation. Our primary outcomes of interest were pre-operative and post-operative functional status. One year survival rate was 100%. All patients had stable or improved American Spine Injury Association score immediately after surgery, which was maintained at 3months in 83.3% of patients. Karnofsky Performance Status (KPS) was stable at 3month follow up in 50% of patients, but all had decreased KPS 1year after surgery. A subset of patients received post-operative radiation and chemotherapy with 0% tumor recurrence rate at 3months. We assessed the molecular profiles of tumors from two patients in our series and found that each had mutations in TP53, but had wildtype BRAF, IDH-1, and MGMT. Taken together, our data show that patients with high grade spinal cord gliomas have an excellent survival at 1year, but with some decline in functional status within this period. Further studies are needed to elucidate the natural history of the disease and to explore the role of adjuvant targeted molecular therapies.

Intramedullary spinal metastasis of a carcinoid tumor.

We report an intramedullary spinal cord metastasis from a bronchial carcinoid, and discuss its mechanisms and management. Intramedullary spinal cord metastases from any cancer are rare, and bronchial carcinoids account for only a small fraction of lung cancers. To our knowledge, an intramedullary spinal cord metastasis from a bronchial carcinoid has been described only once previously.

Reversal of warfarin associated coagulopathy with 4-factor prothrombin complex concentrate in traumatic brain injury and intracranial hemorrhage.

Warfarin-associated intracranial hemorrhage is associated with a high mortality rate. Ongoing coagulopathy increases the likelihood of hematoma expansion and can result in catastrophic hemorrhage if surgery is performed without reversal. The current standard of care for emergency reversal of warfarin is with fresh frozen plasma (FFP). In April 2013, the USA Food and Drug Administration approved a new reversal agent, 4-factor prothrombin complex concentrate (PCC), which has the potential to more rapidly correct coagulopathy. We sought to determine the feasibility and outcomes of using PCC for neurosurgical patients. A prospective, observational study of all patients undergoing coagulopathy reversal for intracranial hemorrhage from April 2013 to December 2013 at a single, tertiary care center was undertaken. Thirty three patients underwent emergent reversal of coagulopathy using either FFP or PCC at the discretion of the treating physician. Intracranial hemorrhage included subdural hematoma, intraparenchymal hematoma, and subarachnoid hemorrhage. FFP was used in 28 patients and PCC was used in five patients. International normalized ratio at presentation was similar between groups (FFP 2.9, PCC 3.1, p=0.89). The time to reversal was significantly shorter in the PCC group (FFP 256 minutes, PCC 65 minutes, p<0.05). When operations were performed, the time delay to perform operations was also significantly shorter in the PCC group (FFP 307 minutes, PCC 159 minutes, p<0.05). In this preliminary experience, PCC appears to provide a rapid reversal of coagulopathy. Normalization of coagulation parameters may prevent further intracranial hematoma expansion and facilitate rapid surgical evacuation, thereby improving neurological outcomes.