The VEBAS score: a practical scoring system for intracranial dural arteriovenous fistula obliteration.

BACKGROUND: Tools predicting intracranial dural arteriovenous fistulas (dAVFs) treatment outcomes remain scarce. This study aimed to use a multicenter database comprising more than 1000 dAVFs to develop a practical scoring system that predicts treatment outcomes. METHODS: Patients with angiographically confirmed dAVFs who underwent treatment within the Consortium for Dural Arteriovenous Fistula Outcomes Research-participating institutions were retrospectively reviewed. A subset comprising 80% of patients was randomly selected as training dataset, and the remaining 20% was used for validation. Univariable predictors of complete dAVF obliteration were entered into a stepwise multivariable regression model. The components of the proposed score (VEBAS) were weighted based on their ORs. Model performance was assessed using receiver operating curves (ROC) and areas under the ROC. RESULTS: A total of 880 dAVF patients were included. Venous stenosis (presence vs absence), elderly age (<75 vs ≥75 years), Borden classification (I vs II-III), arterial feeders (single vs multiple), and past cranial surgery (presence vs absence) were independent predictors of obliteration and used to derive the VEBAS score. A significant increase in the likelihood of complete obliteration (OR=1.37 (1.27-1.48)) with each additional point in the overall patient score (range 0-12) was demonstrated. Within the validation dataset, the predicted probability of complete dAVF obliteration increased from 0% with a 0-3 score to 72-89% for patients scoring ≥8. CONCLUSION: The VEBAS score is a practical grading system that can guide patient counseling when considering dAVF intervention by predicting the likelihood of treatment success, with higher scores portending a greater likelihood of complete obliteration.

A Scoping Review of Simulation-Based Training Paradigms for Carotid Artery Endarterectomy and Carotid Artery Stenting.

BACKGROUND: Surgical simulation has come to the forefront to enhance the training of residents. The aim of our scoping review is to analyze the available simulation-based carotid revascularization techniques, including carotid endarterectomy (CEA) and carotid artery stenting (CAS) and suggest critical steps for evaluating competency in a standardized fashion. METHODS: A scoping review of all reports on simulation-based carotid revascularization techniques including CEA and CAS was performed in PubMed/MEDLINE, Scopus, Embase, Cochrane, Science Citation Index Expanded, Emerging Sources Citation Index, and Epistemonikos databases. Data were collected according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. The English language literature was searched from January 1, 2000 to January 9, 2022. The outcomes evaluated included measures of assessment of operator performance. RESULTS: Five CEA and 11 CAS manuscripts were included in this review. The methods of assessments employed by these studies to judge performance were comparable. The 5 CEA studies sought to validate and demonstrate improved performance with training or distinguish surgeons by their experience level, either through assessing operative performance or end-product results. The 11 CAS studies used 1 of 2 types of commercial simulators and focused on determining the efficacy of simulators as teaching tools. By examining the steps of the procedure associated with preventable perioperative complications, it provides a reasonable framework for determining which elements of the procedure should be emphasized most. Furthermore, using potential errors as a basis for assessment of competency could reliably distinguish operators based on level of experience. CONCLUSIONS: Competency-based simulation training is becoming more relevant as our surgical training paradigm shifts with the increased scrutiny within training programs of work-hour regulations and the need to develop a curriculum to assess our trainees' ability to perform specific operations competently during their stipulated training period. Our review has given us an insight into the current efforts in this space regarding 2 specific procedures that are key for all vascular surgeons to master. Although many competency-based modules are available, there is a lack of standardization in the grading/rating system of what surgeons consider vital steps of each procedure to assess these simulation-based modules. Therefore, the next steps of curriculum development should be based on standardization efforts for the different protocols available.

Absence of the torcular, review of venous sinus anatomy, and the simplified dural sinus classification.

BACKGROUND: Classically, the torcular Herophili is described as the symmetric junction between the superior sagittal sinus (SSS), transverse sinuses (TSs), and straight sinus (SS). However, finding this pattern in practice is not standard. Anatomical variations are common, and different drainage patterns should be expected. Existing literature proposes highly detailed descriptions and classifications of this region. Still, a simplified and practical categorization is not available. METHODS: We present an anatomical finding of the torcular Herophili discovered on a cadaveric dissection. Then, we conducted a retrospective study examining the 100 most recent cranial magnetic resonance venographies (MRVs) from the Mayo Clinic, labeling them with a new proposed dural sinus classification system. Images were initially classified by two authors and further validated by a board-certified neurosurgeon and a board-certified neuroradiologist from our institution. To measure consistency in image identification, two additional international neurosurgeons were asked to classify a subset of the same MRV images, and their answers were compared. RESULTS: Of the MRV cohort, 33 patients were male and 67 were female. Their ages ranged from 18 to 86 years, with a mean of 47.35 years and a median of 49 years. Upon examination, 53 patients presented as confluent (53%), 9 as SSS divergent (9%), 25 as SS divergent (25%), 11 as circular (11%), and 2 as trifurcated (2%). The inter-rater reliability ranked very good; agreement between the two neurosurgeons was 83% (κ = 0.830, p < 0.0005). CONCLUSION: The confluence of the venous sinuses is a highly variable anatomical area that is rarely evaluated with neuroimaging before surgery. The classic textbook configuration is not the rule. Using a simplified classification system may increase awareness and hopefully patient safety by preparing the physician for anatomical variations that they will encounter in a surgical or clinical scenario.

No Sex Differences in the Prevalence of Intracranial Aneurysms in Patients with Ascending Thoracic Aortic Aneurysms: A Multi-Center Experience.

BACKGROUND: Previous studies suggest a coprevalence of intracranial aneurysms (IA) in patients with infrarenal abdominal aortic aneurysms (AAA). We reviewed our multicenter experience in the detection/treatment of IAs in patients with ascending thoracic aortic aneurysms (ATAA) relative to patients without ATAA. METHODS: Surgical cases of ATAA repaired at 3 sites from January 1998 to December 2018 were retrospectively reviewed. Out of these patients, those with intracranial vascular imaging were selected for our study, and these individuals were concurrently randomly matched with a control group of patients who underwent intracranial vascular imaging without an ATAA in a 1:1 ratio by age, sex, smoking history, and year of intracranial vascular imaging. Conditional logistic regression was used to calculate odds ratios (OR). RESULTS: We reviewed 2176 ATAA repairs. 74% (n = 1,615) were men. Intracranial vascular imaging was available in 298 (13.7%) patients. Ninteen patients were found to have 22 IAs for a prevalence of 6.4%. Mean size of IA was 4.6 ± 3.3 mm; mean age at IA detection, 63.4 ± 12.1 years. IA was present on head imaging in 4.7% of male and 12.5% of female patients. Eleven (58%) patients were men. The OR of having IA in female versus male patients is 2.90, 95% confidence interval [CI] [1.08-7.50], P = 0.029. Time from IA diagnosis to ATAA repair was 1.7 ± 116.2 months. Two patients underwent treatment for IA, one ruptured and one unruptured. All were diagnosed before ATAA repair. Treatment included 1 clipping and 1 coiling with subsequent reintervention of the coiling using a flow diversion device. In the matched group of patients who had intracranial vascular imaging without ATAA, the rate of IA is 5.0%. IA was detected in 3.8% of males and 9.4% of female patients for an OR of 2.59, 95% CI [0.84-7.47], P = 0.083. Association within our study and matched groups, the OR of developing an IA with and without ATAA was not statistically significant 1.29, 95% CI [0.642.59], P = 0.48. There was also no evidence of sex differences in the association of ATAA with IA (interaction P = 0.88). The OR for the association of ATAA with IA was 1.33, 95% CI [0.46-3.84], P = 0.59 in females and 1.25, 95% CI [0.49-3.17], P = 0.64 in males. CONCLUSIONS: Our study found that IA was present in 6.4% of patients with ATAA who had intracranial vascular imaging available. The odds of IA were 1.29 times higher than a matched cohort of patients who had intracranial vascular imaging without ATAA but this failed to achieve statistical significance. We found that the odds of IA were more than 2 times higher in females than males for both those with ATAA (OR = 2.90) and those without ATAA (OR = 2.59); however, it only reached statistical significance in those with ATAA.

Natural history, angiographic presentation and outcomes of anterior cranial fossa dural arteriovenous fistulas.

BACKGROUND: Anterior cranial fossa dural arteriovenous fistulas (ACF-dAVFs) are aggressive vascular lesions. The pattern of venous drainage is the most important determinant of symptoms. Due to the absence of a venous sinus in the anterior cranial fossa, most ACF-dAVFs have some degree of drainage through small cortical veins. We describe the natural history, angiographic presentation and outcomes of the largest cohort of ACF-dAVFs. METHODS: The CONDOR consortium includes data from 12 international centers. Patients included in the study were diagnosed with an arteriovenous fistula between 1990-2017. ACF-dAVFs were selected from a cohort of 1077 arteriovenous fistulas. The presentation, angioarchitecture and treatment outcomes of ACF-dAVF were extracted and analyzed. RESULTS: 60 ACF-dAVFs were included in the analysis. Most ACF-dAVFs were symptomatic (38/60, 63%). The most common symptomatic presentation was intracranial hemorrhage (22/38, 57%). Most ACF-dAVFs drained through cortical veins (85%, 51/60), which in most instances drained into the superior sagittal sinus (63%, 32/51). The presence of cortical venous drainage predicted symptomatic presentation (OR 9.4, CI 1.98 to 69.1, p=0.01). Microsurgery was the most effective modality of treatment. 56% (19/34) of symptomatic patients who were treated had complete resolution of symptoms. Improvement of symptoms was not observed in untreated symptomatic ACF-dAVFs. CONCLUSION: Most ACF-dAVFs have a symptomatic presentation. Drainage through cortical veins is a key angiographic feature of ACF-dAVFs that accounts for their malignant course. Microsurgery is the most effective treatment. Due to the high risk of bleeding, closure of ACF-dAVFs is indicated regardless of presentation.

Procedural, workforce, and reimbursement trends in neuroendovascular procedures.

BACKGROUND: This study aims to define the proportion of Medicare neuroendovascular procedures performed by different specialists from 2013 to 2019, map the geographic distribution of these specialists, and trend reimbursement for these procedures. METHODS: The Medicare Provider Utilization Database was queried for recognized neuroendovascular procedures. Data on specialists and their geographic distribution were tabulated. Reimbursement data were gathered using the Physician Fee Schedule Look-Up Tool and adjusted for inflation using the United States Bureau of Labor Statistics' Consumer Price Index Inflation calculator. RESULTS: The neuroendovascular workforce in 2013 and 2019, respectively, was as follows: radiologists (46% vs 44%), neurosurgeons (45% vs 35%), and neurologists (9% vs 21%). Neurologists increased proportionally (p=0.03). Overall procedure numbers increased across each specialty: radiology (360%; p=0.02), neurosurgery (270%; p<0.01), and neurology (1070%; p=0.03). Neuroendovascular revascularization (CPT 61645) increased in all fields: radiology (170%; p<0.01), neurosurgery (280%; p<0.01), neurology (240%; p<0.01); central nervous system (CNS) permanent occlusion/embolization (CPT61624) in neurosurgery (67%; p=0.03); endovascular temporary balloon artery occlusion (CPT61623) in neurology (29%; p=0.04). In 2019, radiologists were the most common neuroendovascular specialists everywhere except in the Northeast where neurosurgeons predominated. Inflation adjusted reimbursement decreased for endovascular temporary balloon occlusion (CPT61623, -13%; p=0.01), CNS transcatheter permanent occlusion or embolization (CPT61624, -13%; p=0.02), non-CNS transcatheter permanent occlusion or embolization (CPT61626, -12%; p<0.01), and intracranial stent placement (CPT61635, -12%; p=0.05). CONCLUSIONS: The number of neuroendovascular procedures and specialists increased, with neurologists becoming more predominant. Reimbursement decreased. Coordination among neuroendovascular specialists in terms of training and practice location may maximize access to acute care.

Resolution of atlanto-occipital cyst with conservative management: A case report and review of the literature.

Background: Spinal synovial cysts are cystic dilatations of synovial sheaths that extrude into the spinal canal. Despite their generally benign behavior, they can cause severe symptoms due to compression of neural structures. They are most commonly found in the lumbar spine and are rare in the cervical region, especially at the atlanto-occipital junction. Case Description: A 65-year-old presented with neck pain and headaches. The magnetic resonance imaging (MRI) revealed a degenerative cyst within the anterior foramen magnum causing anterior spinal cord and brainstem compression. Multiple surgical treatment options were discussed, and he was prescribed methylprednisolone and immobilization of his cervical spine with a rigid collar. One month later, the patient reported dramatic improvement of his symptoms, and no surgery was performed. One year later, his pain had remained much improved with the continued use of the collar and pain management (i.e., using anti-inflammatories and muscle relaxants). The 1-year follow-up MRI showed the atlanto-occipital cyst compressing the cervicomedullary junction had completely resolved along with the brainstem compression. Conclusion: A 65-year-old presented with myelopathy attributed to a large anterior foramen magnum atlanto-occipital cyst compressing the cord. Conservative management for 1 month with a rigid cervical collar and steroids resulted in marked neurological improvement; at 1 year follow-up, the patient was markedly improved with an MR that demonstrated spontaneous cyst regression.

MIS lateral retroperitoneal transpsoas approach allows gross total resection of a giant L4 schwannoma.

In this surgical video, the authors present a successful minimally invasive (MIS) lateral retroperitoneal transpsoas approach for resection of an L4 nerve root schwannoma. They describe the surgical approach in detail, with special emphasis on patient positioning for an orthogonal view, as well as technical nuances throughout the procedure. Using a sequential tubular retractor, they performed a microscopic dissection of the lesion. The tumor was debulked and the tumor capsule was disconnected from the surrounding tissue. During dissection, direct stimulation identified a functional nerve root that was carefully dissected from the tumor capsule. The tumor was then removed en bloc. The video can be found here: https://stream.cadmore.media/r10.3171/2022.3.FOCVID2220.

Interactive Neurosurgery Lecture Series: A Global Education Platform of Tele-Teaching During the Coronavirus Disease 2019 Pandemic and Beyond.

OBJECTIVE: To explore the worldwide impact of a virtual neurosurgery-neuroscience lecture series on optimizing neurosurgical education with tele-teaching. METHODS: A retrospective analysis was performed from our Zoom database to collect data from October 15, 2020, to December 14, 2020, and from September 27, 2021, to December 13, 2021. A comparative analysis of participants in the 2 different time frames was performed to investigate the impact of tele-teaching on neurosurgical education worldwide. To evaluate participant satisfaction, the yearly continuing medical education reports of 2020-2021 were analyzed. Data related to the distribution of lectures by subspecialties were also described. RESULTS: Among the 11 lectures of the first period, 257 participants from 17 countries in 4 different continents were recorded, with a mean of 64 (standard deviation = 9.30) participants for each meeting; 342 attendees participated from 19 countries in 5 continents over the 11 lectures of the second part, with an average of 82.8 (standard deviation = 14.04) attendees; a statistically significant increase in participation between the 2 periods was identified (P < 0.001) A total of 19 (2020) and 21 (2021) participants submitted the continuing medical education yearly survey. More than 86.4% of overall responses considered the lectures "excellent." The main topics reported during lectures in 2020-2021 were related to brain tumors (33.7%) and education (22.1%). CONCLUSIONS: The COVID-19 pandemic has increased the need to introduce new educational approaches for teaching novel ways to optimize patient care. Our multidisciplinary Web-based virtual lecture series could represent an innovative tele-teaching platform in neurosurgical training.

Imaging Characteristics and Reintervention in Patients after Radiation Induced Carotid Artery Stenting.

BACKGROUND: To evaluate and describe the radiographic imaging findings in a series of patients who underwent reintervention after radiation induced carotid artery stenting (RICAS). METHODS: A retrospective review of patients with prior RICAS and subsequent reintervention. RESULTS: We describe 10 patients including 8 male and 2 female patients with 12 reinterventions due to prior diagnosed radiation-induced carotid artery stenosis and subsequent stenting during the period 2000-2019. The rate of reintervention was found to be 10%. The pattern of stenosis is unique to this patient population including specifically long-segment stenosis, proximal and distal to the stent location, which tends not to occur in the atherosclerotic patient population. CONCLUSIONS: Careful surveillance after RICAS is necessary to assess for the risk and the unusual pattern of stenosis to offer reintervention in this high-risk patient population.

Intracranial Aneurysms in Loeys-Dietz Syndrome: A Multicenter Propensity-Matched Analysis.

BACKGROUND: Loeys-Dietz syndrome (LDS) is an autosomal dominant connective tissue disorder characterized by a classic triad of hypertelorism, bifid uvula and/or cleft palate, and generalized arterial tortuosity. There are limited data on the prevalence and rupture risk of intracranial aneurysms (IAs) in the setting of LDS, with no established guidelines. OBJECTIVE: To analyze the prevalence and rupture risk of IA in LDS. METHODS: Electronic medical records of patients with a confirmed diagnosis of LDS and available cerebrovascular imaging were reviewed. Patients were divided into 2 groups based on the presence of IA. Unmatched and propensity-matched analyses were used to identify potential risk factors for aneurysm formation. RESULTS: Records of 1111 patients were screened yielding a total of 60 patients with a diagnosis of LDS. Eighteen (30%) patients had IA, 4 (22.2%) of whom had multiple aneurysms for a total of 24 IAs. Twenty-three (95.8%) aneurysms were located in the anterior circulation; none of them were ruptured. On unmatched analysis, age ( P = .015), smoking history ( P = .034), hypertension ( P = .035), and number of extracranial aneurysms ( P < .001) were significantly higher in patients with IA. After matching for age, sex, race, stroke history, family history, and extracranial aneurysms, smoking history ( P = .009) remained significant. CONCLUSION: Patients with LDS have an increased risk of IAs, especially with a history of smoking. The prevalence rate of IAs in our series was 30%. Screening imaging should be considered at diagnosis, and patients should be encouraged to abstain from smoking. Further studies are needed to elucidate the risk of IA rupture and treatment considerations in this unique population.

Creation of a Proof-of-Concept 3D-Printed Spinal Lateral Access Simulator.

Background Minimally invasive lateral lumbar interbody fusion (LLIF) offers advantages over traditional approaches, providing indirect decompression of neural elements and deformity correction while avoiding many challenges and risks of anterior and posterior approaches. Mastering this technique requires a specialized team, advanced equipment, and sufficient case exposure. Current training is limited to the classic educational model, and alternative training methods such as cadaver labs can be inconvenient, inaccessible, expensive, and incompatible with intraoperative neuromonitoring (IONM) systems. Objective The aim of this study was to create a proof-of-concept, low-cost, fully synthetic lateral lumbar surgical simulator and to increase awareness of the lack of current training alternatives. Methods Standard engineering design and expert interviews of attending neurosurgeons, nurses, engineers, and medical device representatives (n=20) were utilized to determine key elements for the simulator, physical characteristics of the components, and translational strategy. Physical and radiographic testing was performed on multiple thermoplastics to determine appropriateness for inclusion in the simulator. For evaluation of the concept, a descriptive slide deck and questionnaire were sent to 15 U.S. and 15 international surgeons who perform LLIF. Results The lateral access training model (LATM) features the following three components: torso casing, spine module, and IONM feature. This model utilizes operable ABS (acrylonitrile butadiene styrene) 3D-printed lumbar vertebrae, verified for anatomical accuracy and compatibility with fluoroscopy. Additionally, a novel neuromonitoring simulation algorithm was developed to train junior residents on neurological complications. To further highlight the need for lateral training models, 30/30 polled surgeons felt that this simulator has value for the field, 29/30 noted that they would have used the LATM if they had access during training, and 30/30 responded that they would encourage trainees to practice on the LATM. Conclusion The LATM is a first step to provide reliable and inexpensive basic lateral lumbar spine training. While this model is lacking some anatomical features, our simulator offers novel training elements for lateral lumbar transpsoas approaches, which lay the foundation for future models to be built. The need for this training exists, and current gaps in the approach to learning these complex techniques need to be filled due to the inconvenience, cost, and impracticability of standard cadaveric models.

Moral Distress and Moral Injury Among Attending Neurosurgeons: A National Survey.

BACKGROUND: "Moral distress" describes the psychological strain a provider faces when unable to uphold professional values because of external constraints. Recurrent or intense moral distress risks moral injury, burnout, and physician attrition but has not been systematically studied among neurosurgeons. OBJECTIVE: To develop a unique instrument to test moral distress among neurosurgeons, evaluate the frequency and intensity of scenarios that may elicit moral distress and injury, and determine their impact on neurosurgical burnout and turnover. METHODS: An online survey investigating moral distress, burnout, and practice patterns was emailed to attending neurosurgeon members of the Congress of Neurological Surgeons. Moral distress was evaluated through a novel survey designed for neurosurgical practice. RESULTS: A total of 173 neurosurgeons completed the survey. Half of neurosurgeons (47.7%) reported significant moral distress within the past year. The most common cause was managing critical patients lacking a clear treatment plan; the most intense distress was pressure from patient families to perform futile surgery. Multivariable analysis identified burnout and performing ≥2 futile surgeries per year as predictors of distress (P < .001). Moral distress led 9.8% of neurosurgeons to leave a position and 26.6% to contemplate leaving. The novel moral distress survey demonstrated excellent internal consistency (Cronbach alpha = 0.89). CONCLUSION: We developed a reliable survey assessing neurosurgical moral distress. Nearly, half of neurosurgeons suffered moral distress within the past year, most intensely from external pressure to perform futile surgery. Moral distress correlated with burnout risk caused 10% of neurosurgeons to leave a position and a quarter to consider leaving.

Application of Color Doppler Ultrasound to Identify and Repair Postoperative Cerebrospinal Fluid Leak: A Technical Note.

BACKGROUND: Incidental durotomy is a known complication of spinal surgery. Persistent cerebrospinal fluid (CSF) leak after unrecognized durotomy may lead to prolonged hospitalization and significant morbidity. If initial bed rest fails, the surgeon must choose between nontargeted methods such as oversewing the wound and lumbar drain placement or return to the operating room. OBJECTIVE: To report the novel use of color flow doppler (CFD) in conjunction with ultrasound (US) to localize the point of CSF leak, assist with aspiration of the pseudomeningocele, and direct the application of fibrin sealant or epidural blood patch. METHODS: This article includes a description of the technique as a technical note. RESULTS: A 72-year-old man underwent L2-5 laminectomies for spinal stenosis. During the index operation, a durotomy occurred and was repaired primarily. The patient subsequently developed leg weakness, back pain, and bulging of the incision. Using CFD, the site of durotomy was determined. Under direct visualization, 34 mL of CSF was aspirated from the pseudomeningocele and 20 mL of fibrin sealant was placed opposing the durotomy. At 2-month follow-up, CFD confirmed absent flow and MRI demonstrated pseudomeningocele resolution. CONCLUSION: This article represents the first report highlighting the utility of CFD US to guide epidural patch placement for postsurgical CSF leaks. CFD allows localization of the durotomy and direct application of blood or fibrin sealant, potentially increasing the success rate of epidural blood patch in postoperative patients. This approach is less invasive than revision surgery and does not require the prolonged hospitalization of lumbar drainage or other nontargeted interventions.

Robotic-Assisted vs Nonrobotic-Assisted Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Cost-Utility Analysis.

BACKGROUND: Management of degenerative disease of the spine has evolved to favor minimally invasive techniques, including nonrobotic-assisted and robotic-assisted minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Value-based spending is being increasingly implemented to control rising costs in the US healthcare system. With an aging population, it is fundamental to understand which procedure(s) may be most cost-effective. OBJECTIVE: To compare robotic and nonrobotic MIS-TLIF through a cost-utility analysis. METHODS: We considered direct medical costs related to surgical intervention and to the hospital stay, as well as 1-yr utilities. We estimated costs by assessing all cases involving adults undergoing robotic surgery at a single institution and an equal number of patients undergoing nonrobotic surgery, matched by demographic and clinical characteristics. We adopted a willingness to pay of $50 000/quality-adjusted life year (QALY). Uncertainty was addressed by deterministic and probabilistic sensitivity analyses. RESULTS: Costs were estimated based on a total of 76 patients, including 38 undergoing robot-assisted and 38 matched patients undergoing nonrobot MIS-TLIF. Using point estimates, robotic surgery was projected to cost $21 546.80 and to be associated with 0.68 QALY, and nonrobotic surgery was projected to cost $22 398.98 and to be associated with 0.67 QALY. Robotic surgery was found to be more cost-effective strategy, with cost-effectiveness being sensitive operating room/materials and room costs. Probabilistic sensitivity analysis identified robotic surgery as cost-effective in 63% of simulations. CONCLUSION: Our results suggest that at a willingness to pay of $50 000/QALY, robotic-assisted MIS-TLIF was cost-effective in 63% of simulations. Cost-effectiveness depends on operating room and room (admission) costs, with potentially different results under distinct neurosurgical practices.

Dural arteriovenous fistulas without cortical venous drainage: presentation, treatment, and outcomes.

OBJECTIVE: Current evidence suggests that intracranial dural arteriovenous fistulas (dAVFs) without cortical venous drainage (CVD) have a benign clinical course. However, no large study has evaluated the safety and efficacy of current treatments and their impact over the natural history of dAVFs without CVD. METHODS: The authors conducted an analysis of the retrospectively collected multicenter Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) database. Patient demographics and presenting symptoms, angiographic features of the dAVFs, and treatment outcomes of patients with Borden type I dAVFs were reviewed. Clinical and radiological follow-up information was assessed to determine rates of new intracranial hemorrhage (ICH) or nonhemorrhagic neurological deficit (NHND), worsening of venous hyperdynamic symptoms (VHSs), angiographic recurrence, and progression or spontaneous regression of dAVFs over time. RESULTS: A total of 342 patients/Borden type I dAVFs were identified. The mean patient age was 58.1 ± 15.6 years, and 62% were women. The mean follow-up time was 37.7 ± 54.3 months. Of 230 (67.3%) treated dAVFs, 178 (77%) underwent mainly endovascular embolization, 11 (4.7%) radiosurgery alone, and 4 (1.7%) open surgery as the primary modality. After the first embolization, most dAVFs (47.2%) achieved only partial reduction in early venous filling. Multiple complementary interventions increased complete obliteration rates from 37.9% after first embolization to 46.7% after two or more embolizations, and 55.2% after combined radiosurgery and open surgery. Immediate postprocedural complications occurred in 35 dAVFs (15.2%) and 6 (2.6%) with permanent sequelae. Of 127 completely obliterated dAVFs by any therapeutic modality, 2 (1.6%) showed angiographic recurrence/recanalization at a mean of 34.2 months after treatment. Progression to Borden-Shucart type II or III was documented in 2.2% of patients and subsequent development of a new dAVF in 1.6%. Partial spontaneous regression was found in 22 (21.4%) of 103 nontreated dAVFs. Multivariate Cox regression analysis demonstrated that older age, NHND, or severe venous-hyperdynamic symptoms at presentation and infratentorial location were associated with worse prognosis. Kaplan-Meier curves showed no significant difference for stable/improved symptoms survival probability in treated versus nontreated dAVFs. However, estimated survival times showed better trends for treated dAVFs compared with nontreated dAVFs (288.1 months vs 151.1 months, log-rank p = 0.28). This difference was statistically significant for treated dAVFs with 100% occlusion (394 months, log-rank p < 0.001). CONCLUSIONS: Current therapeutic modalities for management of dAVFs without CVD may provide better symptom control when complete angiographic occlusion is achieved.

Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR): rationale, design, and initial characterization of patient cohort.

OBJECTIVE: Cranial dural arteriovenous fistulas (dAVFs) are rare lesions, hampering efforts to understand them and improve their care. To address this challenge, investigators with an established record of dAVF investigation formed an international, multicenter consortium aimed at better elucidating dAVF pathophysiology, imaging characteristics, natural history, and patient outcomes. This report describes the design of the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) and includes characterization of the 1077-patient cohort. METHODS: Potential collaborators with established interest in the field were identified via systematic review of the literature. To ensure uniformity of data collection, a quality control process was instituted. Data were retrospectively obtained. RESULTS: CONDOR comprises 14 centers in the United States, the United Kingdom, the Netherlands, and Japan that have pooled their data from 1077 dAVF patients seen between 1990 and 2017. The cohort includes 359 patients (33%) with Borden type I dAVFs, 175 (16%) with Borden type II fistulas, and 529 (49%) with Borden type III fistulas. Overall, 852 patients (79%) presented with fistula-related symptoms: 427 (40%) presented with nonaggressive symptoms such as tinnitus or orbital phenomena, 258 (24%) presented with intracranial hemorrhage, and 167 (16%) presented with nonhemorrhagic neurological deficits. A smaller proportion (224 patients, 21%), whose dAVFs were discovered incidentally, were asymptomatic. Many patients (85%, 911/1077) underwent treatment via endovascular embolization (55%, 587/1077), surgery (10%, 103/1077), radiosurgery (3%, 36/1077), or multimodal therapy (17%, 184/1077). The overall angiographic cure rate was 83% (758/911 treated), and treatment-related permanent neurological morbidity was 2% (27/1467 total procedures). The median time from diagnosis to follow-up was 380 days (IQR 120-1038.5 days). CONCLUSIONS: With more than 1000 patients, the CONDOR registry represents the largest registry of cranial dAVF patient data in the world. These unique, well-annotated data will enable multiple future analyses to be performed to better understand dAVFs and their management.

Recurrence after cure in cranial dural arteriovenous fistulas: a collaborative effort by the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR).

OBJECTIVE: Cranial dural arteriovenous fistulas (dAVFs) are often treated with endovascular therapy, but occasionally a multimodality approach including surgery and/or radiosurgery is utilized. Recurrence after an initial angiographic cure has been reported, with estimated rates ranging from 2% to 14.3%, but few risk factors have been identified. The objective of this study was to identify risk factors associated with recurrence of dAVF after putative cure. METHODS: The Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) data were retrospectively reviewed. All patients with angiographic cure after treatment and subsequent angiographic follow-up were included. The primary outcome was recurrence, with risk factor analysis. Secondary outcomes included clinical outcomes, morbidity, and mortality associated with recurrence. Risk factor analysis was performed comparing the group of patients who experienced recurrence with those with durable cure (regardless of multiple recurrences). Time-to-event analysis was performed using all collective recurrence events (multiple per patients in some cases). RESULTS: Of the 1077 patients included in the primary CONDOR data set, 457 met inclusion criteria. A total of 32 patients (7%) experienced 34 events of recurrence at a mean of 368.7 days (median 192 days). The recurrence rate was 4.5% overall. Kaplan-Meier analysis predicted long-term recurrence rates approaching 11% at 3 years. Grade III dAVFs treated with endovascular therapy were statistically significantly more likely to experience recurrence than those treated surgically (13.3% vs 0%, p = 0.0001). Tentorial location, cortical venous drainage, and deep cerebral venous drainage were all risk factors for recurrence. Endovascular intervention and radiosurgery were associated with recurrence. Six recurrences were symptomatic, including 2 with hemorrhage, 3 with nonhemorrhagic neurological deficit, and 1 with progressive flow-related symptoms (decreased vision). CONCLUSIONS: Recurrence of dAVFs after putative cure can occur after endovascular treatment. Risk factors include tentorial location, cortical venous drainage, and deep cerebral drainage. Multimodality therapy can be used to achieve cure after recurrence. A delayed long-term angiographic evaluation (at least 1 year from cure) may be warranted, especially in cases with risk factors for recurrence.

Assessing the rate, natural history, and treatment trends of intracranial aneurysms in patients with intracranial dural arteriovenous fistulas: a Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) investigation.

OBJECTIVE: There is a reported elevated risk of cerebral aneurysms in patients with intracranial dural arteriovenous fistulas (dAVFs). However, the natural history, rate of spontaneous regression, and ideal treatment regimen are not well characterized. In this study, the authors aimed to describe the characteristics of patients with dAVFs and intracranial aneurysms and propose a classification system. METHODS: The Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) database from 12 centers was retrospectively reviewed. Analysis was performed to compare dAVF patients with (dAVF+ cohort) and without (dAVF-only cohort) concomitant aneurysm. Aneurysms were categorized based on location as a dAVF flow-related aneurysm (FRA) or a dAVF non-flow-related aneurysm (NFRA), with further classification as extra- or intradural. Patients with traumatic pseudoaneurysms or aneurysms with associated arteriovenous malformations were excluded from the analysis. Patient demographics, dAVF anatomical information, aneurysm information, and follow-up data were collected. RESULTS: Of the 1077 patients, 1043 were eligible for inclusion, comprising 978 (93.8%) and 65 (6.2%) in the dAVF-only and dAVF+ cohorts, respectively. There were 96 aneurysms in the dAVF+ cohort; 10 patients (1%) harbored 12 FRAs, and 55 patients (5.3%) harbored 84 NFRAs. Dural AVF+ patients had higher rates of smoking (59.3% vs 35.2%, p < 0.001) and illicit drug use (5.8% vs 1.5%, p = 0.02). Sixteen dAVF+ patients (24.6%) presented with aneurysm rupture, which represented 16.7% of the total aneurysms. One patient (1.5%) had aneurysm rupture during follow-up. Patients with dAVF+ were more likely to have a dAVF located in nonconventional locations, less likely to have arterial supply to the dAVF from external carotid artery branches, and more likely to have supply from pial branches. Rates of cortical venous drainage and Borden type distributions were comparable between cohorts. A minority (12.5%) of aneurysms were FRAs. The majority of the aneurysms underwent treatment via either endovascular (36.5%) or microsurgical (15.6%) technique. A small proportion of aneurysms managed conservatively either with or without dAVF treatment spontaneously regressed (6.2%). CONCLUSIONS: Patients with dAVF have a similar risk of harboring a concomitant intracranial aneurysm unrelated to the dAVF (5.3%) compared with the general population (approximately 2%-5%) and a rare risk (0.9%) of harboring an FRA. Only 50% of FRAs are intradural. Dural AVF+ patients have differences in dAVF angioarchitecture. A subset of dAVF+ patients harbor FRAs that may regress after dAVF treatment.