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OBJECTIVE Chronic subdural hematoma (cSDH) is a common and challenging pathology to treat due to both the historically high recurrence rate following surgical evacuation and the medical comorbidities inherent in the aging patient population that it primarily affects. Middle meningeal artery (MMA) embolization has shown promise in the treatment of cSDHs, most convincingly to avoid surgical evacuation in relatively asymptomatic patients. Symptomatic patients requiring surgical evacuation may also benefit from perioperative MMA embolization to prevent cSDH recurrence. The goal of this study was to determine the utility of perioperative MMA embolization for symptomatic cSDH requiring surgical evacuation and to assess if there is a decrease in the cSDH recurrence rate compared to historical recurrence rates following surgical evacuation alone. METHODS Symptomatic cSDHs were evacuated using a subdural evacuating port system (SEPS) with 5-mm twist-drill craniostomy in an intensive care unit or by performing a craniotomy in the operating room, using either a small (silver dollar, < 4 cm) or large (≥ 4 cm) craniotomy. MMA embolization was performed perioperatively using angiography, selective catheterization of the MMA, and infusion of polyvinyl particles. Outcomes were assessed clinically and radiographically with interval head CT imaging. RESULTS There were 44 symptomatic cSDHs in 41 patients, with 3 patients presenting with bilateral symptomatic cSDH. All cSDHs were evacuated using an SEPS (n = 18), a silver-dollar craniotomy (n = 16), or a large craniotomy (n = 10). Prophylactic MMA embolization was performed successfully in all cSDHs soon after surgical evacuation. There were no deaths and no procedural complications. There was an overall reduction of greater than 50% or resolution of cSDH in 40/44 (90.9%) cases, regardless of the evacuation procedure used. Of the 44 prophylactic cases, there were 2 (4.5%) cases of cSDH recurrence that required repeat surgical evacuation at the 1-year follow-up. These 2 cSDHs were initially evacuated using an SEPS and subsequently required a craniotomy, thereby representing an overall 4.5% recurrence rate of treated cSDH requiring repeat evacuation. Most notably, of the 26 patients who underwent surgical evacuation with a craniotomy followed by MMA embolization, none had cSDH recurrence requiring repeat intervention. CONCLUSIONS Perioperative prophylactic MMA embolization in the setting of surgical evacuation, via either craniotomy or SEPS, may help to lower the recurrence rate of cSDH.

The COVID-19 pandemic has impacted neurosurgery in unforeseeable ways. Neurosurgical patient care, research, and education have undergone extraordinary modifications as medicine and mankind have adapted to overcome the challenges posed by this pandemic. Some changes will disappear as the situation slowly recovers to a prepandemic status quo. Others will remain: This pandemic has sparked some long-overdue systemic transformations across all levels of medicine, including in neurosurgery, that will be beneficial in the future. In this paper, we present some of the challenges faced across different levels of neurosurgical clinical care, research, and education, the changes that followed, and how some of these modifications have transformed into opportunities for improvement and growth in the future.

Intracranial venous sinus stenting is gaining acceptance as an effective treatment for idiopathic intracranial hypertension (IIH). The typical approach is via femoral venous and arterial access for transvenous stenting with simultaneous angiography. These patients are at an above average risk for groin complications considering obesity is typically associated with IIH and the need for heparinization and dual antiplatelet therapy. Here, we describe cerebral venography, angiography, and venous sinus stenting via a single upper extremity. We utilize a transradial approach for angiography and a venous access via the brachial or basilic vein. Over a series of 28 consecutive procedures, we were able to successfully access the intracranial venous sinuses via the arm without access site complications. This method offers the advantages of immediate patient mobilization after the procedure and more easily monitored and compressible access sites for easier post-procedural care.

Background and purpose This retrospective study evaluates the safety and effectiveness of preoperative endovascular embolization in patients who underwent temporomandibular joint (TMJ) replacement surgery. Material and methods We included all patients treated with preoperative embolization of the internal maxillary artery (IMAX) between June 2016 and January 2019. All patients were treated by the same surgeon using standard surgical approaches and procedures. Periprocedural adverse events, blood loss during surgery and clinical follow-up are reported. Results Fourteen patients (12 females, median age 32.5) were treated with 21 embolizations of the IMAX (bilateral embolizations in seven patients) prior to TMJ replacement surgery with prosthetic joints (TMJ Concepts prostheses). Seven patients presented with TMJ ankylosis/degenerative joint disease/post-trauma deformity, four patients with Idiopathic Condylar Resorption and resultant mandibular displacement/hypoplasia, two patients with rheumatoid arthritis-associated condylar degeneration and resultant loss of mandibular position, and 1 patient being re-reconstructed following management of a prosthetic joint infection. Seven patients underwent bilateral prosthetic joint replacement. Four patients underwent additional facial skeletal surgery as part of their treatment. The mean blood volume loss during TMJ surgery was approximately 370 cc (range 100–800 cc). Joint space-specific blood loss was not recorded, but, as per the surgical team, was significantly decreased when compared to non-embolized patients. There were no intra-procedural complications. The median clinical follow-up was 3.5 months (range 1–24 months). The modified Rankin scale (mRS) was 0 before the procedure and at last clinical follow-up in all patients. After TMJ surgery, three patients reported paresthesia of the trigeminal nerve likely related to the residual condyle resection and two patients had mild facial nerve weakness (Temporal and/or Marginal Mandibular branch) related to the surgical exposures. Conclusion Endovascular preoperative embolization of the IMAX is feasible, safe and likely effective in reducing blood volume loss in complex TMJ replacement surgery.

Background: The COVID-19 pandemic has revealed deficiencies in the adequacy of personal protective equipment (PPE) forhealth care workers. Endoscopic endonasal skull base surgery (ESBS) is thought to be among the highest risk aerosol-generating procedures (AGPs) for surgeons and operating room personnel. Objective: To validate the efficacy and clinical feasibility of a novel surgical device. Methods: A low-cost, modifiable, and easily producible negative pressure, face-mounted antechamber was developedutilizing 3D printing and silicone molding. Efficacy was evaluated using an optical particle sizer (OPS) to quantify aerosolsgenerated during both cadaver and intraoperative human use with high-speed drilling. Results: Particle counts in the cadaver showed that drilling led to a 2.49-fold increase in particles ≤5 μm ( p = 0.001), andthat the chamber was effective at reducing particles to levels not significantly different than baseline. In humans, drillingled to a 37-fold increase in in particles ≤5 μm ( p < 0.001), and the chamber was effective at reducing particles to a level notsignificantly different than baseline. Use of the antechamber in 6 complex cases did not interfere with the ability to performsurgery. Patients did not report any facial discomfort after surgery related to antechamber use. Conclusions: The use of a negative pressure facial antechamber can effectively reduce aerosolization from endoscopicdrilling without disturbing the flow of the operation. The antechamber, in conjunction with appropriate PPE, will be usefulduring the COVID-19 pandemic, as well as during flu season and any future viral outbreaks.

Background Venous sinus stenting (VSS) is an accepted and minimally invasive treatment for adult idiopathic intracranial hypertension (IIH) associated with lateral sinus stenosis (LSS). The efficacy and safety of venous sinus stenting (VSS) in children with IIH has not been established. Methods This is a retrospective analysis of IIH patients 18 years of age or younger with LSS treated with VSS at our institution. Included patients have fulminant disease course or are refractory or intolerant to medical management. Results Eight patients were identified; 4 males and 4 females. Mean age is 13.4 years (range 4–18). All patients had severe headaches, 5 had blurred vision, 3 had diplopia and 3 had pulsatile tinnitus. Papilledema was present in 4 patients. Three patients had prior surgical procedures. Four patients were intolerant to medical management, 3 were refractory and 1 had fulminant course. Cerebral venography demonstrated severe stenosis of the dominant sinus in 6 patients and of bilateral co-dominant sinuses in 2 patients. Six patients had intrinsic stenosis and 2 had extrinsic stenosis. Venous sinus stenting (VSS) resulted in improvement of symptoms, papilledema and normalization of CSF opening pressure in 7 patients. No immediate complications were observed. Mean follow-up period is 21 months (range 6–42). Two patients required re-stenting; one responded well and the other had persistent symptoms and underwent subsequent surgical procedures of CSF diversion, suboccipital decompression and duraplasty which were also ineffective. Conclusion VSS may provide a viable option for pediatric IIH patients who are intolerant to medication, have failed conservative management or prior surgical interventions, or present with fulminant disease.

Background and purpose This retrospective study evaluates the safety and mid-term and long-term effectiveness of stent-assisted coil embolization of anterior communicating artery (Acomm) aneurysms treated with the LVIS Jr stent. Materials and methods All patients treated with the LVIS Jr stent for Acomm aneurysms between June 2015 and March 2018 were included in the analysis. Details of the procedure’s periprocedural adverse events, immediate aneurysm occlusion rates, and clinical and angiographic follow-up assessment were collected. Results A total of 25 patients with 25 aneurysms were included. Eighteen aneurysms were found incidentally. Seven patients presented with seven ruptured aneurysms: Six were remotely ruptured and one acutely ruptured. Twenty-four patients were treated successfully and one technical failure is reported. The parent arteries measured 1.4 mm to 2.9 mm in diameter (mean, 2.3 mm). Intraprocedural thromboembolic complications occurred in two patients (8%) and an intraoperative aneurysm rupture in one patient (4%). Immediate complete aneurysm occlusion was noted in 18 out of 25 patients (72%). Clinical follow-up ranged from three months to 36 months (mean, 15.8 months) and the imaging follow-up ranged from two to 35 months (mean, 14.2 months). Complete aneurysm occlusion was achieved in 14 out of 20 patients (70%) at last angiographic follow-up. Of the two patients with in-stent thrombosis, one patient had an acutely ruptured aneurysm and the other patient was treated with an LVIS Jr stent in a Y configuration. Neurological morbidity and mortality rate were 0%. Conclusions Complex, wide-necked Acomm aneurysms can be effectively treated with stent-assisted embolization using LVIS Jr stents.

In this article, we report three cases of dural arteriovenous fistulas of the hypoglossal canal treated via transvenous approach. We also perform a review of the literature on the endovascular management of this type of lesions with particular attention to the dangerous extracranial-intracranial anastomoses that can occur at this level.

Pathologic vertebral compression fractures (VCF) are relatively common in patients with metastatic cancer and can significantly affect quality of life. Historically, these painful and sometimes debilitating fractures have been treated conservatively with pain medications and bracing. Minimally invasive vertebral augmentation procedures (VAP), including vertebroplasty and kyphoplasty, are now available and have been proven to alleviate pain and improve quality of life for select patients. Diagnosing symptomatic pathologic compression fractures and identifying those patients who would benefit from VAP in a timely manner are essential. This includes understanding the potential complications and absolute contraindications of VAP so as to minimize the potential risks while carefully selecting those patients who are likely to benefit based on their clinical history, physical exam findings, and diagnostic imaging. Radiofrequency ablation is a recently described procedure that can be performed as a stand-alone therapy or in conjunction with VAP for pathologic VCF to provide pain relief and potentially aid in local tumor control.

Venous sinus stenting is an accepted and minimally invasive treatment for idiopathic intracranial hypertension associated with significant venous sinus stenosis. There is inherent difficulty in navigating past the region of venous stenosis in order to safely deliver and deploy a stent. We have developed the “Cobra” technique, which allows for the safe and efficient navigation past regions of high-grade venous sinus stenosis.

OBJECTIVEEarly surgical intervention for pediatric refractory epilepsy is increasingly advocated as surgery has become safer and data have demonstrated improved outcomes with early seizure control. There is concern that the risks associated with staged invasive electroencephalography (EEG) in very young children outweigh the potential benefits. Here, the authors present a cohort of children with refractory epilepsy who were referred for invasive monitoring, and they evaluate the role and safety of staged invasive EEG in those 3 years old and younger.METHODSThe authors conducted a retrospective review of children 3 years and younger with epilepsy, who had been managed surgically at two institutions between 2001 and 2015. A cohort of pediatric patients older than 3 years of age was used for comparison. Demographics, seizure etiology, surgical management, surgical complications, and adverse events were recorded. Statistical analysis was completed using Stata version 13. A p < 0.05 was considered statistically significant. Fisher’s exact test was used to compare proportions.RESULTSNinety-four patients (45 patients aged ≤ 3 [47.9%]) and 208 procedures were included for analysis. Eighty-six procedures (41.3%) were performed in children younger than 3 years versus 122 in the older cohort (58.7%). Forty-two patients underwent grid placement (14 patients aged ≤ 3 [33.3%]); 3 of them developed complications associated with the implant (3/42 [7.14%]), none of whom were among the younger cohort. Across all procedures, 11 complications occurred in the younger cohort versus 5 in the older patients (11/86 [12.8%] vs 5/122 [4.1%], p = 0.032). Two adverse events occurred in the younger group versus 1 in the older group (2/86 [2.32%] vs 1/122 [0.82%], p = 0.571). Following grid placement, 13/14 younger patients underwent guided resections compared to 20/28 older patients (92.9% vs 71.4%, p = 0.23).CONCLUSIONSWhile overall complication rates were higher in the younger cohort, subdural grid placement was not associated with an increased risk of surgical complications in that population. Invasive electrocorticography informs management in very young children with refractory, localization-related epilepsy and should therefore be used when clinically indicated.

Background and purpose This retrospective study evaluates the safety and effectiveness of preoperative endovascular embolization in patients who underwent temporomandibular joint (TMJ) replacement surgery. Material and methods We included all patients treated with preoperative embolization of the internal maxillary artery (IMAX) between June 2016 and January 2019. All patients were treated by the same surgeon using standard surgical approaches and procedures. Periprocedural adverse events, blood loss during surgery and clinical follow-up are reported. Results Fourteen patients (12 females, mean age 32.5) were treated with 19 embolizations of the internal maxillary artery (bilateral embolizations in 7 patients) prior to TMJ replacement surgery with prosthetic joints (TMJ Concepts prostheses). Seven patients presented with TMJ ankylosis/degenerative joint disease/post-trauma deformity, 4 patients with Idiopathic Condylar Resorption and resultant mandibular displacement/hypoplasia, 2 patients with rheumatoid arthritis-associated condylar degeneration and resultant loss of mandibular position, and 1 patient being re-reconstructed following management of a prosthetic joint infection. Seven patients underwent bilateral prosthetic joint replacement. Four patients underwent additional facial skeletal surgery as part of their treatment. The median blood volume loss during TMJ surgery was approximately 370 cc per patient and 246 cc per TMJ replacement surgery (range 100 cc to 800 cc). Joint space-specific blood loss was not recorded but, as per the surgical team, was significantly decreased when compared to non-embolized patients. There were no intra-procedural complications. The mean clinical follow-up was 7.1 months (range 1–24 months). The modified Rankin scale (mRS) was 0 before the procedure and at last clinical follow-up in all patients. After TMJ surgery, 3 patients reported paresthesia of the trigeminal nerve likely related to the residual condyle resection and 3 patients had mild facial nerve weakness (Temporal and/or Marginal Mandibular branch) related to the surgical exposures. Conclusion Endovascular preoperative embolization of the internal maxillary artery (IMAX) is feasible and safe and likely effective in reducing blood volume loss in complex TMJ replacement surgery. Disclosures A. Santillan: None. M. Sur: None. J. Schwarz: None. K. Brown: None. E. Rogol: None. D. Behrman: None. A. Patsalides: None.

Background and purpose This retrospective study evaluates the safety, effectiveness and long-term clinical and angiographic follow up of intracranial aneurysms treated with LVIS Jr. stent and parent vessels diameter equal or less than 2.5 mm. Materials and methods We included all patients treated with LVIS Jr stent in aneurysms with small parent vessel diameter between March 2015 and July 2017. Periprocedural adverse events, immediate aneurysm occlusion rates and clinical and angiographic follow-up are reported. Results A total of 35 patients with 35 aneurysms were included. Ten aneurysms were ruptured (28.6%) and 25 were unruptured (71.4%). The parent arteries measured 0.9 mm to 2.5 mm in diameter (mean, 2.2 mm). Intra-procedural thromboembolic complications occurred in 4 patients (11.4%) and an intra-operative aneurysm rupture in 1 patient (2.8%). Immediate complete aneurysm occlusion was noted in 21 out of 35 patients (60%). The clinical follow-up ranged between 1 and 25 months (mean, 10.5 months) and the MRA follow up ranged between 4 and 24 months (mean, 10.4 months). Complete aneurysm occlusion was achieved in 21 out of 29 patients (72.4%) at last angiographic follow-up (mean, 9.4 months; range 4 to 23 months). In-stent stenosis occurred in 1 out of 29 patients (3.4%), which was asymptomatic. From the 4 patients with in-stent thrombosis, 3 patients were treated with ‘Y configuration’ (2 patients with MCA aneurysms and 1 patient with an Acomm aneurysm). Mortality rate was 0%. Neurological morbidity was 2.9%. Disclosures A. Santillan: None. S. Boddu: None. J. Schwarz: None. N. Lin: None. Y. Gobin: None. J. Knopman: None. A. Patsalides: None.

Purpose Three-Dimensional (3D) guidance has not been widely adopted in interventional neuro-radiology (INR) despite the recognized role of 3D imaging for diagnostic and therapeutic purposes. The objective of the study was to describe our experience using a new bi-plane 3D guidance software (Vessel ASSIST, GE Healthcare) for INR procedures and identify a subset of procedures which would benefit the most from it. Material and methods Between Mar-2017 and Feb-2018 bi-plane 3D guidance was made available for INR procedures, in addition to conventional 2D roadmap. The decision to use 3D guidance was based on anticipated procedure difficulty and availability of pre-operative images. For brain aneurysms and arteriovenous pathologies, diagnostic trans-arterial catheter injected 3D acquisition was used to segment vessels or structures of interest, which were then overlaid on top of fluoroscopy on the frontal and lateral plane with automatic registration. For transvenous procedures, vessels of interest were first segmented using the time of flight sequence of a pre-operative magnetic resonance venogram (MRV). Two non-contrast fluoroscopic frames of the skull on each plane were used to register the MRV with fluoroscopy before venous access. After bi-plane 3D guidance was used, an operator filled questionnaire recorded: 1- feasibility of the technique in terms of timing and accuracy, 2- perceived benefits of the technique compared to conventional 2D guidance, and 3- if fusion on both planes had been used. Results Guidance using an intra-operative 3D acquisition or pre-operative MRV was reported feasible and appropriately accurate in all cases with both automatic and semi-automatic registration. Fusion on both planes was used in 30 cases. More specifically, guidance using intra-operative 3D acquisition was reported superior to conventional 2D roadmapping for complex aneurysm coiling and arteriovenous fistula (AVF) embolization. Use of pre-operative MRV 3D guidance was reported useful for trasnvenous access for embolization of AVF and for venous sinus stenting (VSS) procedures, providing visibility of the cortical veins without need for arterial injection. Operators reported better anatomical path visualization, increased confidence in approaching the lesion and increased confidence during the treatment, compared to 2D visualization alone. Conclusion Bi-plane 3D guidance using either pre-operative or per-operative images is feasible and safe for procedures such as complex aneurysm, AVF and VSS. Further studies should quantify the benefits on procedure time, radiation dose, contrast media and operator confidence. Disclosures A. Santillan: None. J. Schwarz: None. G. Avignon: 5; C; General Electric. P. Ozbek: 5; C; General Electric. A. Patsalides: None.

Objective The A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) trial has received fierce criticism, including considerable selection bias, poor generalizability, questionable clinical practices (only 15.8% underwent surgical resection, the gold standard for arteriovenous malformation [AVM] treatment), and short follow-up (33 months) for a disease process that carries a life-long risk. In this study, we sought to present our own experience treating unruptured brain AVMs to provide supporting evidence of the ARUBA trial criticism. Methods All cases of treated brain AVMs from 2004 to 2017 at our institution were retrospectively reviewed and included in the analysis if they met ARUBA trial inclusion criteria. The primary outcome was symptomatic stroke or death. Secondary outcomes included AVM obliteration, long-term clinical impairment (modified Rankin Scale score >1), and new major or minor postoperative deficit. Results Of the 245 reviewed cases, 86 met the ARUBA trial criteria. Treatment included microsurgical resection alone (2.3%), preoperative embolization followed by microsurgical resection (62.8%), stereotactic radiosurgery alone (10.5%), embolization followed by stereotactic radiosurgery (15.1%), and embolization alone (9.3%). The primary outcome was met in 8.3%, new perioperative major and minor complications occurred in 5.8% and 12.8%, and long-term clinical impairment in 4.5%. AVM obliteration was observed in 92.4% overall and in 100% of patients who underwent surgical resection. Conclusions The criticism of the ARUBA trial is warranted, as our study found that treatment of unruptured brain AVMs has an acceptable safety profile when approached in a multidisciplinary manner at an experienced institution, using surgical resection as the primary treatment modality when applicable.

Background Embolization of the middle meningeal artery (MMA) has recently been proposed as an alternative to surgery for treatment of chronic subdural hematoma (SDH). There is increasing evidence that fragile neovasculature arising from distal branches of the MMA found within the membrane that forms around a chronic SDH is responsible for high recurrence rates due to chronic, repeated rebleeding. Embolization of the MMA could thus potentially eliminate the blood supply to this membrane and prevent further rebleeding. Methods The cases of 6 patients with 7 recurrent SDHs treated with MMA embolization with polyvinyl alcohol particles were retrospectively reviewed. Results MMA embolization was performed successfully in all 6 patients with no complications. Of the 7 SDHs treated, 1 required surgical reevacuation due to recurrence. The other 6 were able to avoid surgery, with reduction in size from 12 mm to 11 mm over 3 weeks, 14 mm to 9 mm over 9 weeks, 21 mm to 5 mm over 31 weeks, 17 mm to 9 mm over 12 weeks, 18 mm to 3 mm over 8 weeks, and 25 mm to 6 mm over 24 weeks. All patients had resolution of symptoms at longest follow-up. Conclusions In this case series of 6 patients harboring 7 recurrent, chronic SDHs, 6 of the 7 were successfully treated with MMA embolization and able to avoid surgery for reevacuation, suggesting that this minimally invasive technique may represent an effective alternative to surgery.

Background and purpose This retrospective study evaluates the safety, effectiveness, and long-term clinical and angiographic follow-up of intracranial aneurysms treated with the Low-Profile Visualized Intraluminal Support Junior (LVIS Jr.) stent and parent vessels of diameter equal to or less than 2.5 mm. Materials and methods We included all patients treated with the LVIS Jr. stent in aneurysms with small parent vessel diameter between March 2015 and July 2017. Periprocedural adverse events, immediate aneurysm occlusion rates, and clinical and angiographic follow-up are reported. Results A total of 35 patients with 35 aneurysms were included. Ten aneurysms were ruptured (28.6%) and 25 were unruptured (71.4%). The parent arteries measured 0.9 mm to 2.5 mm in diameter (mean, 2.2 mm). Intra-procedural thromboembolic complications occurred in four patients (11.4%) and there was an intraoperative aneurysm rupture in one patient (2.8%). Immediate complete aneurysm occlusion was noted in 21 out of 35 patients (60%). Clinical follow-up ranged between one and 25 months (mean, 10.5 months) and magnetic resonance angiography follow-up ranged between four and 24 months (mean, 10.4 months). Complete aneurysm occlusion was achieved in 21 out of 29 patients (72.4%) at last angiographic follow-up (mean, 9.4 months; range four to 23 months). In-stent stenosis occurred in one out of 29 patients (3.4%), who was asymptomatic. Of the four patients with in-stent thrombosis, three patients were treated with “Y configuration” (two patients with middle cerebral artery aneurysms and one patient with an anterior communicating artery aneurysm). Mortality rate was 0%. Neurological morbidity was 2.9%. Conclusions Stenting with the LVIS Jr. stent allowed us to treat complex intracranial aneurysms with parent vessel diameter of 2.5 mm or less with an acceptable safety profile.

Background Endoscopic endonasal (EE) transsphenoidal surgery is an important surgical approach to the treatment of sellar pathology, particularly for pituitary adenomas. Risk factors for the radiographic recurrence of pituitary adenomas resected using a purely endoscopic approach have not been established. This study investigates outcomes and identifies risk factors for recurrence following EE transsphenoidal surgery for pituitary adenoma. Methods We performed a retrospective review of 64 patients with pituitary adenomas undergoing EE surgery by a single, right-handed surgeon preferentially operating through the right nares. Post-operative MRI studies were utilized to monitor for residual disease or disease recurrence. Results Residual tumor was found in 31.2% of patients. Over a median follow-up period of 23.1 months (range 4–62.5), 4 (20%) of these patients showed recurrence. Two patients with inconclusive post-operative imaging had subsequent imaging consistent with recurrence, making the total recurrence in our series 9.4%. While no statistically significant effects of gender, age or history of previous treatment were seen, amenorrhea on presentation and maximum tumor diameter >10 mm were significant risk factors for radiographic recurrence (p = 0.044 and 0.005, respectively). No predominant side of residual tissue was identified in these tumors operated through the right nares. Conclusions Only 20% of patients with residual tumor developed recurrent disease over a median follow up of 23.1 months. This recurrence rate may be an important consideration in cases where gross total resection is not feasible. Preferentially operating from the right does not seem to influence the location of residual tumor.

Spinal dural arteriovenous fistulas (SDAVF) are a rare pathologic entity with a diverse and often misleading clinical presentation. While digital subtraction spinal angiography remains the gold standard, recent advances in noninvasive vascular imaging have improved the diagnosis of SDAVF. As this condition can result in permanent spinal cord injury, all patients require treatment, which consists of surgical or endovascular occlusion of the fistula. Failure to recognize and treat SDAVF in a timely fashion can result in irreversible neurologic disability, including myelopathy, lower extremity weakness and bowel, bladder and sexual dysfunction. This article reviews the clinical features, pathogenesis, radiographic features and current treatment strategies for these complex lesions.