Synthetic interpolated DSA for radiation exposure reduction via gamma variate contrast flow modeling: a retrospective cohort study.

BACKGROUND: Digital subtraction angiography (DSA) yields high cumulative radiation dosages (RD) delivered to patients. We present a temporal interpolation of low frame rate angiograms as a method to reduce cumulative RDs. METHODS: Patients undergoing interventional evaluation and treatment of cerebrovascular vasospasm following subarachnoid hemorrhage were retrospectively identified. DSAs containing pre- and post-intervention runs capturing the full arterial, capillary, and venous phases with at least 16 frames each were selected. Frame rate reduction (FRR) of the original DSAs was performed to 50%, 66%, and 75% of the original frame rate. Missing frames were regenerated by sampling a gamma variate model (GVM) fit to the contrast response curves to the reduced data. A formal reader study was performed to assess the diagnostic accuracy of the "synthetic" studies (sDSA) compared to the original DSA. RESULTS: Thirty-eight studies met inclusion criteria (average RD 1,361.9 mGy). Seven were excluded for differing views, magnifications, or motion. GVMs fit to 50%, 66%, and 75% FRR studies demonstrated average voxel errors of 2.0 ± 2.5% (mean ± standard deviation), 6.5 ± 1.5%, and 27 ± 2%, respectively for anteroposterior projections, 2.0 ± 2.2%, 15.0 ± 3.1%, and 14.8 ± 13.0% for lateral projections, respectively. Reconstructions took 0.51 s/study. Reader studies demonstrated an average rating of 12.8 (95% CI 12.3-13.3) for 75% FRR, 12.7 (12.2-13.2) for 66% FRR and 12.0 (11.5-12.5) for 50% FRR using Subjective Image Grading Scale. Kendall's coefficient of concordance resulted in W = 0.506. CONCLUSION: FRR by 75% combined with GVM reconstruction does not compromise diagnostic quality for the assessment of cerebral vasculature. RELEVANCE STATEMENT: Using this novel algorithm, it is possible to reduce the frame rate of DSA by as much as 75%, with a proportional reduction in radiation exposure, without degrading imaging quality. KEY POINTS: • DSA delivers some of the highest doses of radiation to patients. • Frame rate reduction (FRR) was combined with bolus tracking to interpolate intermediate frames. • This technique provided a 75% FRR with preservation of diagnostic utility as graded by a formal reader study for cerebral angiography performed for the evaluation of cerebral vasospasm. • This approach can be applied to other types of angiography studies.

Disparities in Postoperative Endocrine Outcomes After Endoscopic-Assisted Transsphenoidal Pituitary Adenoma Resection.

Objectives Socioeconomic factors can influence morbidity in patients with pituitary adenoma. This study aims to identify associations between socioeconomic factors and postoperative outcomes in patients with pituitary adenomas. Methods A retrospective medical chart review was conducted on adult patients who underwent resection of purely sellar nonfunctional and functional pituitary adenomas between May 1, 2014, and May 31, 2020, at the University of North Carolina Medical Center. The main outcome measures included the incidence of postoperative diabetes insipidus (PDI), postoperative hyponatremia (PHN), and postoperative hypopituitarism (PHP). Outcome measures were analyzed using univariate and multivariate analyses against preoperative tumor volume as well as socioeconomic and demographic factors (self-identified race/ethnicity, age, gender, address assessed by the Area Deprivation Index (ADI), and insurance status). Results On univariate analysis, patients of Hispanic race/ethnicity and patients living in more disadvantaged neighborhoods had an increased incidence of postoperative diabetes insipidus. Patients who experienced PDI were significantly younger on average in both univariate and multivariate analyses. When analyzed further, patients of Hispanic race/ethnicity were significantly younger and more likely to be uninsured compared to their respective racial/ethnic counterparts. No significant correlations were found for PHN or PHP. Conclusions Patients of Hispanic race/ethnicity and patients living in more disadvantaged neighborhoods were more likely to experience PDI. This finding, when combined with findings regarding age and insurance status, suggests complex disparities in medical care that are confirmed or corroborated by prior literature. These results may enhance clinicians' management of patients from disadvantaged socioeconomic backgrounds through increased awareness of disparities and the provision of resources for assistance.

Comparative Outcomes by Surgical Approach in Patients with Malignant Sinonasal Disease.

Objective There is a paucity of data on comparative outcomes for open versus endoscopic surgery for patients with malignant sinonasal pathology. Most of the available studies are limited by a sample size <100 patients. Design This is a retrospective cohort study. Setting The findings of this study come from a single-institution tertiary care center from 2008 to 2019. Participants In total, 199 patients who underwent surgery for malignant sinonasal disease participated in this study. Main Outcome Measures The main outcome measures were perioperative complications and reoperation. Results Patients in our sample had a mean age of 59.7 years (SD, 20.4). In total, 62% were male and 72% were white. An endoscopic-only approach was used in 41% of patients and an open or combined approach in 59% of patients. Squamous cell carcinoma was the most common pathology (43.0%), followed by sarcoma (9.5%), skin cancer (6.5%), sinonasal undifferentiated carcinoma (6.5%), and adenocarcinoma (5.5%). The all-cause complication rate was 14.6%. Patients with an open resection had a higher rate of intraoperative complications (5.9 vs. 0%; p = 0.043), postoperative complications (19.5 vs. 3.7%; p = 0.001), and all-cause complications (21.0 vs. 3.7%; p < 0.001). The likelihood of early reoperation (<6 months) or late reoperation (>6 months) did not significantly differ by surgical approach ( p = 1.000 and 0.741, respectively). Conclusion The endoscopic approach for resection of malignant sinonasal disease is viable for select patients and may be associated with a favorable complication rate compared with the open approach.

Cumulative Radiation Exposure in Aneurysmal Subarachnoid Hemorrhage: A Single-Institution Analysis.

OBJECTIVE: Diagnosis and management of aneurysmal subarachnoid hemorrhage (aSAH) depend heavily on imaging modalities that repeatedly expose patients to ionizing radiation. There is limited literature on cumulative radiation exposure in this patient population, which is a problem compounded by wide variation among institutions. The present study quantifies the cumulative cranial exposure to ionizing radiation resulting from diagnostic medical imaging and medical procedures during initial hospitalization for ruptured aSAH at a single academic institution and estimates the risk of future adverse events related to radiation injury. METHODS: We performed a retrospective observational study of adults who presented to our institution during a nearly 3-year period with acute-onset aSAH, which was confirmed with diagnostic imaging, and had the aneurysm treated with either surgical clip ligation or endovascular embolization. RESULTS: A total of 131 patients met the inclusion criteria. Eighty-eight patients (67%) were treated with endovascular embolization and 43 (32%) were treated with clip ligation. We found the average radiation dose to the head during the incident hospitalization for aSAH to be 4.40 Gy (95% confidence interval, 3.91-4.89). Angiography and interventional radiology procedures accounted for most of this exposure. CONCLUSIONS: Most patients were exposed to levels of ionizing radiation that put them at considerable risk of deterministic radiation injury. Providers should be aware of the potential consequences of acute and long-term radiation exposure in this patient population, so they can monitor and counsel individuals accordingly and take steps to safely limit radiation exposure during aSAH management.

Pentobarbital Coma Use in a Pregnant Patient With Refractory Intracranial Hypertension: A Case Report.

OBJECTIVE: Intracranial hypertension is a life-threatening condition that requires emergent diagnosis and management. Although pentobarbital coma for refractory intracranial hypertension has been studied in the general population, this study is the first reported case of pentobarbital coma use in a pregnant patient. METHODS: We performed a retrospective chart review of a pregnant patient with refractory intracranial hypertension and reviewed the current literature on the role of pentobarbital coma. RESULTS: We present the case of a 35-year-old woman at 26 weeks of gestation who developed refractory intracranial hypertension secondary to rupture of a dural arteriovenous fistula. The patient was taken to surgery for decompressive hemicraniectomy, clot evacuation, and dural arteriovenous fistula resection. Subsequently, the patient was treated with pentobarbital coma for 5 days and achieved adequate control of her intracranial pressures. The patient and fetus were closely monitored by the obstetrics team with no apparent harm to fetal well-being during her hospital stay. The patient underwent planned cesarean delivery at term, and both the mother and newborn were discharged in stable condition with no known pentobarbital-related complications. CONCLUSIONS: Thus, we present the first case report demonstrating that pentobarbital coma may be a safe and efficacious option for treating pregnant patients with life-threatening refractory intracranial hypertension. We also provide dosing information for pentobarbital administration. Additional studies and reports involving pregnant patients are needed to better understand the impact of pentobarbital on both the mother and fetus. Furthermore, long-term follow-up of both the mother and newborn is critical to identifying any delayed sequelae of neonatal exposure to pentobarbital.

Bilateral Decompressive Hemicraniectomy for Diffuse Cerebral Edema and Medically Refractory Elevated Intracranial Pressure in Aneurysmal Subarachnoid Hemorrhage: A Case Series.

Decompressive hemicraniectomy (DCHC) may be indicated in the setting of subarachnoid hemorrhage (SAH) complicated by persistent elevated intracranial pressure (ICP) that is refractory to medical interventions. Outcomes can be variable as indications for surgery can include focal hematomas, infarctions, and regional or diffuse edema. Bilateral DCHC for medically refractory elevated ICP in the setting of SAH is not well described in the literature, and the viability of this option in terms of patient outcomes is unclear. We describe the cases of four patients with medically refractory ICP secondary to diffuse cerebral edema who underwent bilateral DCHC in the setting of SAH. This is a retrospective case review of four patients with aneurysmal SAH who underwent bilateral DCHC for management of diffuse global edema resulting in medically refractory ICP. We describe two patients who made impressive recoveries after bilateral DCHC and two patients who required significant continued care needs despite ICP control in all patients. Bilateral DCHC is a viable option for control of refractory elevated ICP in SAH patients who develop diffuse cerebral edema. Bilateral DCHC in this setting can be considered after exhaustion of other therapeutic options.

Rabbit Elastase Aneurysm: Imaging and Histology Correlates for Inflammation and Healing.

OBJECTIVE: Aneurysmal subarachnoid hemorrhage remains a devastating event with poorly understood pathophysiology. Previous studies have suggested that aneurysm wall inflammation may play a part in the development and potential rupture of aneurysms. The rabbit elastase aneurysm model is a well-established model, which produces aneurysms closely mimicking human cerebral aneurysms in flow dynamics and histopathology. The primary aim of this study was to correlate inflammatory changes after aneurysm formation using sequential vessel wall imaging with histopathologic analysis. A secondary aim was to evaluate the potential effect of gender and anti-inflammatory treatment with aspirin on this inflammatory response. METHODS: Twenty-seven New Zealand rabbits underwent surgery to create an aneurysm using elastase infusion at the right common carotid artery origin. Vessel wall imaging and histopathologic analysis was obtained at different time points after aneurysm creation. The rabbits were also randomized by gender and to treatment groups with or without aspirin. RESULTS: Histopathologic analysis revealed 3 distinct phases after aneurysm formation. These phases were an initial inflammatory phase, followed by a regeneration phase, and finally a connective tissue deposition phase. Vessel wall imaging demonstrated 2 distinct imaging patterns. No appreciable differences were seen in histology or imaging when comparing gender or treatment with aspirin. CONCLUSIONS: Inflammatory changes induced by the rabbit elastase aneurysm model can be correlated with histopathologic findings and observed on noninvasive vessel wall imaging. This may provide a method to study the inflammatory pathway as it pertains to aneurysmal development and subsequent rupture.

Outcomes of Endoscopic Versus Open Skull Base Surgery in Pediatric Patients.

OBJECTIVE/HYPOTHESIS: To characterize the pathology and outcomes of skull base surgery in the pediatric population by open versus endoscopic surgical approach. STUDY DESIGN: Retrospective cohort study. METHODS: A retrospective review of pediatric patients (<18 years) who underwent skull base surgery for nonmalignant disease from May 2000 to August 2019 was performed. Patient demographics, pathology, and operative characteristics by surgical approach were recorded and analyzed. Patients with a combined endoscopic/open approach were classified as open for the analysis. RESULTS: Eighty-two pediatric skull base patients were identified with a mean age of 11.3 years (standard deviation 5.2). A purely endoscopic approach was used in 63 (77%) patients, a purely open approach was used in nine (11%) patients, and a combined open/endoscopic approach was used in 10 (12%) patients. The all-cause complication rate was 9.8%. There was no statistically significant difference in rate of complications between patients with an open versus endoscopic approach for resection (15.8% vs. 7.9%; P = .379). Risk of having a complication did not significantly vary by patient age. The odds of having a complication with an open approach was not statistically significant in a multivariable model adjusted for age, sex, race, intraoperative cerebrospinal fluid leak, tracheostomy requirement, and vascular flap use (odds ratio 2.76, 95% confidence interval 0.28-26.94; P = .383). CONCLUSIONS: Our retrospective study demonstrates a similar risk of complication for open versus endoscopic approach to resection in pediatric skull base patients at our institution. Safety and feasibility of the endoscopic approach has previously been demonstrated in children, and this is the first study to directly compare outcomes with open approaches. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:996-1001, 2021.

Analysis of anterior and posterior maneuvers to enhance intraconal exposure.

BACKGROUND: The medial and inferior recti encompass the ideal surgical corridor to approach the intraconal space endonasally. Here, we describe 3 different maneuvers to achieve greater access to orbital contents through an expanded endonasal approach (EEA). METHODS: Four human cadaver heads were dissected bilaterally (n = 8). EEA to the medial intraconal orbit was executed. The following 3 maneuvers were performed: (1) anterior: extraocular muscles control (EOM); (2) posterior: annulus of Zinn (AZ) release; and (3) anterior/posterior combined. Measurements of the inferior and medial rectus corridor at the level of anterior ethmoidal artery (AEA) and posterior ethmoidal artery (PEA) and extent of optic nerve and medial rectus visualization was performed before and after each maneuver. RESULTS: Medial rectus length (MRL) and optic nerve length (ONL) achieved were 1.72 ± 0.28 cm and 0.85 ± 0.2 cm, respectively. Mean caudal-rostral distances between the rectus muscles at the level of the AEA and PEA were 3.45 ± 0.7 mm and 1.30 ± 0.3 mm, respectively. After EOM control, mean caudal-rostral distances at the same level were as follows: AEA 4.90 ± 1.15 mm (p = 0.009) and PEA 1.70 ± 0.20 mm (p = 0.016). With AZ release, MRL was 2.20 ± 0.7 cm (p = 0.002) and ONL was 1.30 ± 0.2 cm (p = 0.003), with mean rostral-caudal distance at the level of AEA at 4.03 ± 0.8 mm (p = 0.16) and PEA at 1.71 ± 0.36 mm (p = 0.039). Mean caudal-rostral distances achieved with AZ release and EOM control were as follows: AEA 5.6 ± 1.2 mm (p = 0.001) and PEA 2.15 ± 0.4 mm (p = 0.001). CONCLUSION: Progressive access to the orbital contents is afforded with the 3 delineated maneuvers. The magnitude of access is optimized with the combined maneuver. The actual anterior/posterior location of the target will determine which maneuvers are required.

Outcomes of Open vs Endoscopic Skull Base Surgery in Patients 70 Years or Older.

Importance: The use of skull base surgery in patients 70 years or older is increasing, but its safety in this age group has not been evaluated to date. Objectives: To describe outcomes in a cohort of patients 70 years or older undergoing skull base surgery and to evaluate whether age, type of disease process, and approach (endoscopic vs traditional open surgery) are associated with increased intraoperative and postoperative complications in this population. Design, Setting, and Participants: This retrospective cohort study analyzed a population-based sample of 219 patients 70 years or older from a database of 1720 patients who underwent skull base surgery at University of North Carolina Hospitals, Chapel Hill, a tertiary referral center, between October 2007 and June 2017. Data were collected from June 2016 to July 2017 and analyzed in July 2017 and August 2017. Exposure: Skull base surgery. Main Outcomes and Measures: Data collected included demographic characteristics, surgical approach, and disease process. Intraoperative findings and postoperative complications were analyzed by age, surgical approach, and malignancy status. Results: Of the 219 patients, 166 were aged 70.0 to 79.9 years and 53 patients were older than 80 years (mean [SD] age, 76.4 [4.7] years); 120 (54.8%) were men and 160 (73.7%) were white. There were 161 (73.5%) endoscopic and 58 (26.5%) open operations. The most common pathologic processes among the 219 patients were nonsellar malignant (81 [37.0%]), nonsellar benign (53 [24.2%]), and pituitary (49 [22.4%]) tumors. The most common intraoperative and postoperative complications were intraoperative major bleeding (5 of 219 patients [2.3%]) and postoperative bleeding (9 [4.1%]). Thirty-day mortality was zero. There was no clinically meaningful difference in complications between patients aged 70.0 to 79.9 years vs those older than 80 years, endoscopic vs open surgery, or benign vs malignant neoplasms. Specifically, between the endoscopic and open surgery groups, there was no difference in intraoperative major bleeding (3.9%; 95% CI, -0.7% to 12.9%), postoperative cerebrospinal fluid leak (-0.6%; 95% CI, -3.4% to 5.6%), or postoperative bleeding (1.5%; 95% CI, -3.9% to 10.6%). Conclusions and Relevance: Skull base surgery is a safe option in persons 70 years or older, with similar outcomes across age ranges, surgical approaches, and disease processes.

Neoplastic Cerebral Aneurysm From Metastatic Nonsmall Cell Lung Carcinoma: Case Report and Literature Review.

BACKGROUND AND IMPORTANCE: Intracranial cerebral aneurysms secondary to neoplastic etiology are a very rare occurrence. There have only been 5 published reports of intracranial cerebral aneurysms secondary to metastatic lung cancer. Four of those five previously published reports have been secondary to nonsmall cell lung carcinoma, and only 1 case caused subarachnoid hemorrhage. To our knowledge, this is the first report of a lung cancer-associated superior cerebellar artery aneurysm. CLINICAL PRESENTATION: A 41-yr old male presented with right-sided cerebellar hemorrhage. Cerebral angiogram was negative, but he was noted to have an underlying nonsmall cell carcinoma. His workup revealed a left upper lobe mass consistent with a diagnosis of metastatic lung carcinoma. A few weeks later, the patient represented with subarachnoid hemorrhage from a left superior cerebellar artery aneurysm that was new in comparison with a magnetic resonance angiography 19 d earlier. The aneurysm was remote to the surgical site, and the patient had a negative infectious workup, making an iatrogenic pseudoaneurysm or mycotic aneurysm unlikely. In the setting of metastatic cancer, a neoplastic cerebral aneurysm was the presumptive diagnosis. CONCLUSION: Intracranial neoplastic cerebral aneurysms are extremely rare entities, and a rare cause of subarachnoid hemorrhage. This diagnosis should be considered in patients who present with concurrent metastatic cancer and cerebral aneurysm or aneurysmal subarachnoid hemorrhage. Early initiation of chemotherapy may be beneficial in reducing the risk of tumor-particle embolization, but more research needs to be conducted to better understand this rare phenomenon.

The incidence of radiation necrosis following stereotactic radiotherapy for melanoma brain metastases: the potential impact of immunotherapy.

Stereotactic radiotherapy (SRT) is the standard treatment for patients with limited number of brain metastases. In the past few years, newer immunotherapies (immune checkpoint inhibitors) have been proven to prolong survival in patients with metastatic melanoma. The safety of the combination of SRT and immunotherapy for brain metastases is unknown. We retrospectively identified patients with melanoma brain metastases treated with SRT between 2007 and 2015. Patients who did not have at least 3 months of follow-up with imaging after SRT were excluded from the analysis. Outcomes were compared between patients who were treated with or without immunotherapy. A total of 58 patients were included; of these, 29 were treated with SRT and immunotherapy. MAPK inhibitors (BRAF, MEK inhibitors) were used more often in the immunotherapy group (nine vs. two patients). There was a higher incidence of intracranial complications in patients treated with immunotherapy and SRT. Eight patients had radiation necrosis; all occurred in patients who were treated with immunotherapy. Nine patients had hemorrhage, of which seven occurred in patients who were treated with immunotherapy (P=0.08). However, patients treated with immunotherapy and SRT had a significant overall survival advantage compared with SRT without immunotherapy (15 vs. 6 months, P=0.0013). Patients treated with SRT and immunotherapy have a higher incidence/risk of intracranial complications, but a longer overall survival.

A New Window for the Treatment of Posterior Cerebral Artery, Superior Cerebellar Artery, and Basilar Apex Aneurysm: The Expanded Endoscopic Endonasal Approach.

OBJECTIVE: To explore the feasibility of an endoscopic endonasal transclival approach to treat aneurysms arising in the basilar apex, posterior cerebral arteries, and superior cerebellar arteries. STUDY DESIGN: Cadaveric anatomical study. PARTICIPANTS: Fifteen cadaveric specimens. MAIN OUTCOME MEASURES: Degree of surgical exposure of each artery attained, distance from the nasal vestibule to these three arteries, and feasibility of clipping these vessels using standard vascular clip applicators. RESULTS: Both posterior cerebral arteries were exposed, 0.67 cm (standard deviation [SD]: 0.2) on the right side and 0.59 cm (SD: 0.2) on the left side. Both right and left superior cerebral arteries were exposed, 0.6 cm (SD: 0.2) and 0.7 cm (SD: 0.3), respectively. The length of the basilar artery exposed was 2.6 cm (SD: 0.3). The distance from the nasal vestibule to the posterior cerebral artery, superior cerebellar artery, and basilar apex was 10 cm with an SD of ± 0.7, 0.6, and 0.8 cm, respectively. We were able to apply clips on each of these three vessels with a minimal alteration of surrounding normal tissue. CONCLUSION: The endoscopic endonasal transclival approach represents a potentially feasible surgical corridor to treat aneurysms arising from these vessels.

Using the Endoscopic Endonasal Transclival Approach to Access Aneurysms Arising from AICA, PICA, and Vertebral Artery: An Anatomical Study.

Objective To explore the use of the endoscopic endonasal transclival approach (EEA) for clipping anterior inferior cerebellar artery (AICA), posterior inferior cerebellar artery (PICA), and vertebral artery (VA) aneurysms. Design Anatomical study. Participants Fifteen adult cadavers. Main Outcome Measures Length of artery exposed and distance from the nasal ala to the arteries. Results The length of the right and left VA exposed were 1.7 ± 0.6 cm and 1.6 ± 0.6 cm, respectively. The distance to the right VA was 11.1 ± 0.9 cm and to the left was 11.1 ± 0.8 cm. Right and left AICA were exposed for an average length of 1.1 ± 0.3 cm and 0.8 ± 0.3 cm, respectively. The distance to the right AICA was 10.3 ± 0.8 cm and to the left was 10.3 ± 0.8 cm. The right PICA was exposed for a length of 0.5 ± 0.2 cm at a distance of 10.9 ± 0.5 cm. The left PICA was exposed for a length of 0.5 ± 0.2 cm at a distance of 11.1 ± 0.9 cm. Conclusion The EEA can provide direct access to AICA, PICA, and VA, making it a potential alternative to the traditional approaches for the clipping of aneurysms arising from those arteries.

Imaging in Endoscopic Cranial Skull Base and Pituitary Surgery.

Endoscopic endonasal approaches have widely accepted techniques for managing benign and malignant processes along the entire ventral skull base with similar or better results compared with open procedures, but with lower rates of complication. Managing pathology affecting the skull base can be challenging because of complex anatomy and the proximity of critical neurovascular structures. Postoperative imaging can be challenging, because of surgical alterations of normal anatomy and the now common use of complex reconstruction techniques. Understanding the normal imaging appearance of skull base reconstruction is important for accurate postoperative interpretation and delineation between normal reconstructive tissue and recurrent neoplasm.

Endoscopic sinonasal meningoencephalocele repair: a 13-year experience with stratification by defect and reconstruction type.

OBJECTIVE: Sinonasal meningoencephalocele is a rare defect, with varying etiologies and treatment strategies. Here we present the largest published series from a single institution of patients with endoscopic repair. The primary goal is to examine rates of success with consideration to accompanying patient demographic data. The secondary goal is to report the results stratified by defect and reconstruction type. DESIGN: Retrospective consecutive case series. SETTING: Tertiary care academic center. SUBJECTS AND METHODS: Consecutive patients with CPT codes for skull base meningoencephalocele repair between May 2000 and March 2013 were reviewed. Patients who specifically had sinonasal defects were included. RESULTS: During the study period, 149 cases of sinonasal meningoencephaloceles were managed in 133 patients. Mean follow-up was 21.3 months (range, 0-116). There was a success rate of 88% for initial repair, with mean recurrence time of 8.3 months (range, 0-38), and a success rate of 93.8% for initial recurrence surgery, with 99.3% of ultimate successful repair. All cases were repaired endoscopically. Recurrence rate was not significantly related to location of defect (P = .682), size of defect (P = .434), particular reconstruction technique (P = .163), or etiology (trauma, P = .070). Overall complication rate was 11.3%. CONCLUSION: Endoscopic sinonasal meningoencephalocele repair has excellent long-term results and may be considered as a primary approach. Surgeon comfort with a particular technique should be the most important factor used to guide choice of reconstruction.

Endoscopic endonasal approaches to infratemporal fossa tumors: a classification system and case series.

OBJECTIVES/HYPOTHESIS: To propose a clinically applicable anatomic classification system describing three progressive endoscopic endonasal approaches (EEAs) to the infratemporal fossa (ITF) and their potential sequelae. Overall feasibility and outcomes of these approaches are presented through a consecutive case series. STUDY DESIGN: Description of classification system for EEAs to the ITF and case series. METHODS: A classification system of EEAs to ITF tumors was created based on the senior author's clinical experience and cadaveric dissection. A retrospective chart review of 21 child and adult patients with primary ITF tumors treated by these approaches from 2008 to 2012 at a tertiary-care academic medical center was conducted. RESULTS: Three progressive EEAs to ITF tumors were defined: 1) a transpterygopalatine fossa approach, 2) a transmedial pterygoid plate approach, and 3) a translateral pterygoid plate approach. Twenty-one patients treated with these approaches were identified consecutively, with a mean age of 44.2 years (range, 11-79 years). Tumors primarily involving the pterygopalatine fossa and not the ITF were excluded. Pathology included three advanced juvenile nasopharyngeal angiofibromas, three adenoid cystic carcinomas, two recurrent inverted papillomas, two trigeminal schwannomas, and 11 other diverse skull base pathologies. No intraoperative or postoperative complications occurred, with a mean follow-up of 21.5 months (range, 1-55 months). Expected potential sequelae such as V2/palatal numbness, Eustachian tube dysfunction, and trismus occurred in 10/21 patients. CONCLUSIONS: EEAs to ITF tumors are technically feasible with low risk of complications for well-selected patients. The proposed classification system is useful for anticipating potential sequelae for each approach.

A multicenter retrospective study of frameless robotic radiosurgery for intracranial arteriovenous malformation.

INTRODUCTION: CT-guided, frameless radiosurgery is an alternative treatment to traditional catheter-angiography targeted, frame-based methods for intracranial arteriovenous malformations (AVMs). Despite the widespread use of frameless radiosurgery for treating intracranial tumors, its use for treating AVM is not-well described. METHODS: Patients who completed a course of single fraction radiosurgery at The University of North Carolina or Georgetown University between 4/1/2005-4/1/2011 with single fraction radiosurgery and received at least one follow-up imaging study were included. All patients received pre-treatment planning with CTA ± MRA and were treated on the CyberKnife (Accuray) radiosurgery system. Patients were evaluated for changes in clinical symptoms and radiographic changes evaluated with MRI/MRA and catheter-angiography. RESULTS: Twenty-six patients, 15 male and 11 female, were included in the present study at a median age of 41 years old. The Spetzler-Martin grades of the AVMs included seven Grade I, 12 Grade II, six Grade III, and one Grade IV with 14 (54%) of the patients having a pre-treatment hemorrhage. Median AVM nidal volume was 1.62 cm(3) (0.57-8.26 cm(3)) and was treated with a median dose of 1900 cGy to the 80% isodose line. At median follow-up of 25 months, 15 patients had a complete closure of their AVM, 6 patients had a partial closure, and 5 patients were stable. Time since treatment was a significant predictor of response, with patients experience complete closure having on average 11 months more follow-up than patients with partial or no closure (p = 0.03). One patient experienced a post-treatment hemorrhage at 22 months. CONCLUSION: Frameless radiosurgery can be targeted with non-invasive MRI/MRA and CTA imaging. Despite the difficulty of treating AVM without catheter angiography, early results with frameless, CT-guided radiosurgery suggest that it can achieve similar results to frame-based methods at these time points.

Endoscopic endonasal transclival approaches: case series and outcomes for different clival regions.

Objective Transclival endoscopic endonasal approaches to the skull base are novel with few published cases. We report our institution's experience with this technique and discuss outcomes according to the clival region involved. Design Retrospective case series. Setting Tertiary care academic medical center Participants All patients who underwent endoscopic endonasal transclival approaches for skull base lesions from 2008 to 2012. Main Outcome Measures Pathologies encountered, mean intraoperative time, intraoperative complications, gross total resection, intraoperative cerebrospinal fluid (CSF) leak, postoperative CSF leak, postoperative complications, and postoperative clinical course. Results A total of 49 patients underwent 55 endoscopic endonasal transclival approaches. Pathology included 43 benign and 12 malignant lesions. Mean follow-up was 15.4 months. Mean operative time was 167.9 minutes, with one patient experiencing an intraoperative internal carotid artery injury. Of the 15 cases with intraoperative cerebrospinal fluid (CSF) leaks, 1 developed postoperative CSF leak (6.7%). There were six other postoperative complications: four systemic complications, one case of meningitis, and one retropharyngeal abscess. Gross total resection was achieved for all malignancies approached with curative intent. Conclusions This study provides evidence that endoscopic endonasal transclival approaches are a safe and effective strategy for the surgical management of a variety of benign and malignant lesions. Level of Evidence 4.

Beyond the nasoseptal flap: outcomes and pearls with secondary flaps in endoscopic endonasal skull base reconstruction.

OBJECTIVES/HYPOTHESIS: Endoscopic endonasal skull base surgery defects require effective reconstruction. Although the nasoseptal flap (NSF) has become our institution's workhorse for large skull base defects with cerebrospinal fluid (CSF) leaks, situations where it is unavailable require secondary flaps. Clinical outcomes, pearls and pitfalls, and an algorithm will be presented for these secondary flaps. STUDY DESIGN: Clinical case series. METHODS: Medical records of all endoscopic endonasal skull base surgeries at a tertiary care academic medical center were reviewed for skull base defect type, reconstruction method, CSF leak rate, and flap necrosis rate. RESULTS: Of 330 flaps for reconstructing endoscopic endonasal skull base defects, secondary flaps were used in 34 cases (10%). These included 16 endoscopic-assisted pericranial flaps, seven tunneled temporoparietal fascia flaps, three inferior turbinate flaps, two middle turbinate flaps, two anterior lateral nasal wall flaps, two palatal flaps, one occipital flap, and one facial artery buccinator flap. There were 19 anterior cranial fossa defects, 10 clival defects, three sellar defects, and one frontal and one lateral orbit/middle fossa defect. Twenty-five of the 34 cases (73.5%) had either prior or postoperative radiation therapy. The most common pathology was sinonasal cancer, with 16 cases (47.1%). The postoperative CSF leak rate was 3.6% due to one middle turbinate flap necrosis. CONCLUSIONS: Secondary flaps for skull base reconstruction can be harvested with minimally invasive techniques and demonstrate excellent success rates (97%) that are comparable to that of the NSF (>95%). Multiple flaps for complex skull base defects should be in the armamentarium of comprehensive skull base surgery centers. LEVEL OF EVIDENCE: 4.