The lateral based nasopharyngeal flap: A novel vascularized flap for skull base reconstruction.

As the indications for endoscopic skull base approaches have increased, so has the need for more versatile vascularized flaps for skull base reconstruction. Here, we describe a novel lateral based nasopharyngeal flap (LNPF). Two cadaver heads were dissected to elucidate flap anatomy, dimensions, and technique. A retrospective review was performed on two cases where LNPF was used to repair CSF leaks in the nasopharyngeal area, and outcomes reported. The LNPF is an ascending pharyngeal artery myomucosal flap that includes the nasopharyngeal mucosa and the superior pharyngeal constrictor muscle. The flap was 1.2 × 2.2 cm in greatest dimensions. The LNPF was used for salvage CSF leak repair in two cases: one clival and one tubal. Both patients had resolution of leak at 7 months follow-up. The LNPF is a novel flap with reconstruction potential for the nasopharynx, including the lower clivus and the eustachian tube.

Use of Tympanostomy T-Tube for Endoscopic Endonasal Marsupialization of Small Rathke's Cleft Cysts: A Case Series.

Objectives This article describes a novel technique implementing the use of a tympanostomy t-tube to provide long-term marsupialization of small Rathke's cleft cysts (RCCs). Design A retrospective review of electronic medical records was performed to collect demographic and clinical data on a series of four patients. Setting Academic medical center. Participants Four female patients (mean age of 34 years) underwent transsphenoidal endoscopic endonasal surgery for RCC. All four patients presented with headaches. Mean cyst size was 7 mm. Two of the four surgeries were revisions for RCC recurrence. Main Outcome Measures Symptom resolution after surgery, duration of follow-up, and feasibility of the proposed technique. Results Tympanostomy t-tube was used to marsupialize small RCCs (< 10 mm) for four patients. Three patients remained symptom-free with endoscopy and imaging showing patent t-tubes at 21 months' (range 20-24 months) follow-up. One patient experienced severe migraines immediately after surgery. Migraines were relieved after t-tube was removed 6 weeks after surgery. Conclusion Tympanostomy t-tubes placed via an endoscopic endonasal approach can provide long-term marsupialization for small RCCs.

Revisiting flow augmentation bypass for cerebrovascular atherosclerotic vaso-occlusive disease: Single-surgeon series and review of the literature.

OBJECTIVE: Despite advances in the nonsurgical management of cerebrovascular atherosclerotic steno-occlusive disease, approximately 15-20% of patients remain at high risk for recurrent ischemia. The benefit of revascularization with flow augmentation bypass has been demonstrated in studies of Moyamoya vasculopathy. Unfortunately, there are mixed results for the use of flow augmentation in atherosclerotic cerebrovascular disease. We conducted a study to examine the efficacy and long term outcomes of superficial temporal artery to middle cerebral artery (STA-MCA) bypass in patients with recurrent ischemia despite optimal medical management. METHODS: A single-institution retrospective review of patients receiving flow augmentation bypass from 2013-2021 was conducted. Patients with non-Moyamoya vaso-occlusive disease (VOD) who had continued ischemic symptoms or strokes despite best medical management were included. The primary outcome was time to post-operative stroke. Time from cerebrovascular accident to surgery, complications, imaging results, and modified Rankin Scale (mRS) scores were aggregated. RESULTS: Twenty patients met inclusion criteria. The median time from cerebrovascular accident to surgery was 87 (28-105.0) days. Only one patient (5%) had a stroke at 66 days post-op. One (5%) patient had a post-operative scalp infection, while 3 (15%) developed post-operative seizures. All 20 (100%) bypasses remained patent at follow-up. The median mRS score at follow up was significantly improved from presentation from 2.5 (1-3) to 1 (0-2), P = .013. CONCLUSIONS: For patients with high-risk non-Moyamoya VOD who have failed optimal medical therapy, contemporary approaches to flow augmentation with STA-MCA bypass may prevent future ischemic events with a low complication rate.

Retrolabyrinthine transsigmoid approach to complex parabrainstem tumors in the posterior fossa.

OBJECTIVE: The surgical management of large and complex tumors of the posterior fossa poses a formidable challenge in neurosurgery. The standard retrosigmoid craniotomy approach has been performed at most neurosurgical centers; however, the retrosigmoid approach may not provide enough working space without significant retraction of the cerebellum. The transsigmoid approach provides wider and shallower surgical fields; however, there have been few clinical and no cadaveric studies on its usefulness. In the present study, the authors describe the transsigmoid approach in clinical cases and cadaveric specimens. METHODS: For the clinical study, the authors retrospectively reviewed the medical records and operative charts of patients who had been surgically treated for parabrainstem tumors using the transsigmoid approach between 1997 and 2019. They analyzed patient demographic and clinical data, as well as surgical and clinical outcomes. In the cadaveric study, they compared the surgical views obtained in different approaches (retrosigmoid, presigmoid, retrolabyrinthine, and transsigmoid) and measured the sigmoid sinus width at the level of the endolymphatic sac and the distance between the anterior edge of the sigmoid sinus and the endolymphatic sac on 35 sides in 19 cadaveric specimens. RESULTS: A total of 21 patients (6 males and 15 females) with a mean age of 42.2 (range 15-67) years were included in the clinical study. Eleven patients had meningioma, 7 had vestibular schwannoma, 2 had hemangioblastoma, and 1 had epidermoid cyst. Gross-total, near-total, and subtotal removal were achieved in 7 (33.3%), 3 (14.3%), and 11 (52.4%) patients, respectively. In the cadaveric study, 19 cadaveric specimens were used. The sigmoid sinus was cut in the middle, and the incision was extended from the retrosigmoid to the presigmoid dura. The dura was then retracted upward and downward like opening a door. The results indicated that this technique can widen the operative field anteriorly by approximately 2 cm as compared to the retrosigmoid approach and provides a better view anterior to the brainstem. CONCLUSIONS: The transsigmoid approach is useful for complex parabrainstem tumors in the posterior fossa because it provides a wider and shallower operative view with less retraction of the cerebellum. This enables safer tumor removal with less damage to important structures in the posterior fossa, resulting in better operative and clinical outcomes.

Olfactory-Specific Quality of Life Outcomes after Endoscopic Endonasal Surgery of the Sella.

OBJECTIVE: To assess olfactory outcomes as measured by an olfactory-specific quality of life (QOL) questionnaire in patients undergoing EESBS for sellar lesions. DESIGN: Retrospective case series. SETTING: Tertiary academic medical center. PARTICIPANTS: In total, 36 patients undergoing EESBS for lesions limited to the sella were evaluated. MAIN OUTCOME MEASURES: The following were performed before and three months after surgery: 22-Item Sinonasal Outcomes Test (SNOT-22), University of Pennsylvania Smell Identification Test (UPSIT), and the Assessment of Self-reported Olfactory Functioning (ASOF), which has three domains: subjective olfactory capability scale (SOC), smell-related problems (SRP), and olfactory-related quality of life (ORQ). RESULTS: Median age at surgery was 52.5 years, with a median tumor size of 1.8 cm (range: 0.2 to 3.9 cm). Pre- and postoperative median scores were 35 [34, 36.2] and 34.5 [32, 36] for UPSIT, 21 [7.5, 33.5] and 21.5 [6.8, 35.7] for SNOT-22, 10 [9, 10] and 9 [8, 10] for ASOF-SOC, 5 [4.8, 5] and 4.5 [4, 5] for ASOF-SRP, and 5 [5, 5] and 5 [4.5, 5] for ASOF-ORQ. There was no significant change in the two of the three domains of the ASOF. Correlation between ASOF and UPSIT scores were weak. Older age and larger tumor size were associated with worsened olfaction after surgery. CONCLUSIONS: Patients did not experience significant changes in olfactory-specific QOL three months after EESBS, as measured by two domains of the ASOF. The ASOF may serve as a useful adjunctive tool for assessing olfaction after surgery. The lack of correlation between UPSIT and ASOF suggests the need for more research in subjective olfactory-related quality of life after surgery.

Petrous bone lesions: surgical implementation and outcomes of extradural subtemporal approach.

BACKGROUND: Petrous bone lesions (PBLs) are rare with few reports in the neurosurgical literature. In this study, the authors describe our current technique of extradural subtemporal approach (ESTA). The objective of this study was to evaluate the role and efficacy of ESTA for treatment of the PBLs. To our knowledge, this is the largest reported clinical series of using an ESTA-treated PBLs in which the clinical outcomes were evaluated. METHODS: Between 1994 and 2019, 67 patients with PBLs treated by ESTA were retrospectively reviewed. Extent of resection, neurological outcomes, recurrence rate, and surgical complications were evaluated and compared with previous studies. The indications, advantages, limitations, and outcomes of ESTA were analyzed according to pathology. RESULTS: This series included 7 facial nerve schwannomas (10.4%), 16 cholesterol granulomas (23.9%), 16 chordomas (23.9%), 6 chondrosarcomas (9%), 5 trigeminal schwannomas (7.5%), 9 epidermoids/dermoids (13.4%), and 8 other pathologies (11.9%). The most common location of PBLs operated with ESTA was at the petrous apex and rhomboid areas (68.7%). Gross total resection was achieved in 35 (55.6%). Symptomatic improvement occurred in 56 patients (83.6%). Complications occurred in 7 (10.4%) of cases including one mortality. Nine patients (17%) had recurrence within the mean follow-up 71 months. Compared to previous literature, our results demonstrated comparable outcomes but with higher rates of hearing and facial nerve preservation as well as minimal morbidity. From our results, ESTA is an effective therapeutic option for lesions located at the rhomboid and petrous apex, particularly when patients presented with intact facial and hearing function. CONCLUSION: Our series demonstrated that ESTA provided satisfactory outcomes with excellent benefits of hearing and facial function preservation for patients with petrous bone lesions. ESTA should be considered as a safe and effective therapeutic option for selected patients with PBLs.

Neurosurgical management of petrous bone lesions: classification system and selection of surgical approaches.

BACKGROUND: Surgery of petrous bone lesions (PBLs) is challenging for neurosurgeons. Selection of the surgical approach is an important key for success. In this study, the authors present an anatomical classification for PBLs that has been used by our group for over the past 26 years. The objective of this study is to investigate the benefits and applicability of this classification. METHODS: Between 1994 and 2019, 117 patients treated for PBLs were retrospectively reviewed. Using the V3 and arcuate eminence as reference points, the petrous bone is segmented into 3 parts: petrous apex, rhomboid, and posterior. The pathological diagnoses, selection of the operative approach, and the extent of resection (EOR) were analyzed and correlated using this classification. RESULTS: This series included 22 facial nerve schwannomas (18.8%), 22 cholesterol granulomas (18.8%), 39 chordomas/chondrosarcomas (33.3%), 6 trigeminal schwannomas (5.1%), 13 epidermoids/dermoids (11.1%), and 15 other pathologies (12.8%). PBLs were most often involved with the petrous apex and rhomboid areas (46.2%). The extradural subtemporal approach (ESTA) was most frequently used (57.3%). Gross total resection was achieved in 58.4%. Symptomatic improvement occurred in 92 patients (78.6%). Our results demonstrated a correlation between this classification with each type of pathology (p < .001), selection of surgical approaches (p < 0.001), and EOR (p = 0.008). Chordoma/chondrosarcoma, redo operations, and lesions located medially were less likely to have total resection. Temporary complications occurred in 8 cases (6.8%), persistent morbidity in 5 cases (4.3%), and mortality in 1 case. CONCLUSION: In this study, we proposed a simple classification of PBLs. Using landmarks on the superior petrosal surface, the petrous bone is divided into 3 parts, apex, rhomboid, and posterior. Our results demonstrated that chordoma/chondrosarcoma, redo operations, and lesions involving the tip of the petrous apex or far medial locations were more difficult to achieve total resection. This classification could help surgeons understand surgical anatomy framework, predict possible structures at risk, and select the most appropriate approach for each patient.

How I do it: total resection of a giant sphenoclinoidal meningioma with normalization of near blind vision.

BACKGROUND: Resection of giant sphenoclinoidal meningiomas (SCLM) remains difficult. We discuss a patient presenting with right eye near blindness who underwent total removal of a giant SCLM, resulting in normal vision and no recurrence. METHOD: Utilizing frontotemporal craniotomy, devascularization, debulking, and detachment was achieved. Microdissection of tumor off the optic nerve and carotid perforators was accomplished, resulting in total resection, visual normalization, and no deficits using efficient face-to-face microscope set-up, 2-surgeon 4-hand technique, and double bipolar-suction arrangement. CONCLUSION: Frontotemporal craniotomy was adequate. Preservation of the optic nerve and carotid artery is key. Meticulous microsurgical techniques and refined instruments are important for success.

Extradural anterior temporal fossa approach to the paranasal sinuses, nasal cavities through the anterolateral and anteromedial triangles: Combined microscopic and endoscopic strategy.

OBJECTIVE: To demonstrate the utility and limitations of the extradural endoscopic-assisted anterior temporal fossa approach to the pterygopalatine fossa (PPF), infratemporal fossa (ITF), paranasal sinuses (PS), parapharyngeal region (PPR), nasal cavities (NC), epipharynx (EP), and clivus. METHODS: A frontotemporal orbitozygomatic craniotomy is performed. The dura is elevated from the cavernous sinus (CS). The anterior temporal fossa floor is drilled. Foramen rotundum and ovale are opened. The PPF is exposed and the lateral margin of inferior orbital fissure (IOF) is removed. The anterolateral triangle (ALT) is drilled and the vidian nerve (VN) is exposed. Drilling between the maxillary nerve (V2) and the VN provides access to the sphenoid sinus (SphS). The medial pterygoid plate is drilled exposing the EP. The maxillary sinus (MaxS) is opened anterior to the PPF. V2 is transposed laterally to enlarge the anteriomedial triangle (AMT). The orbital muscle of Muller is removed as well as the medial margin of the IOF, which opens the SphS. Anteriorly, the posterior ethmoid air cells are opened. Morphometric measurements evaluating the size of the ALT were done and the PS, NC, EP were explored with the endoscope. RESULTS: The ALT and AMT triangle provides a wide exposure of the PPF, ITF, PPR. In addition, those triangles represent a deep entry point to explore the PS, NC, and EP. CONCLUSION: The ALT and AMT are useful corridors to access to the SphS, MaxS, PS, NC, and EP via a transcranial approach. The use of the endoscope through this corridor widely extend the extradural anterior temporal fossa approach which may be considered as a valuable alternative to the extended endoscopic endonasal approach for selected skull base lesions extending both intracranial and into the PS, NC and EP.

Safety of the APOLLO Onyx delivery microcatheter for embolization of brain arteriovenous malformations: results from a prospective post-market study.

BACKGROUND: Catheter retention and difficulty in retrieval have been observed during embolization of brain arteriovenous malformations (bAVMs) with the Onyx liquid embolic system (Onyx). The Apollo Onyx delivery microcatheter (Apollo) is a single lumen catheter designed for controlled delivery of Onyx into the neurovasculature, with a detachable distal tip to aid catheter retrieval. This study evaluates the safety of the Apollo for delivery of Onyx during embolization of bAVMs. METHODS: This was a prospective, non-randomized, single-arm, multicenter, post-market study of patients with a bAVM who underwent Onyx embolization with the Apollo between May 2015 and February 2018. The primary endpoint was any catheter-related adverse event (AE) at 30 days, such as unintentional tip detachment or malfunction with clinical sequelae, or retained catheter. Procedure-related AEs (untoward medical occurrence, disease, injury, or clinical signs) and serious AEs (life threatening illness or injury, permanent physiological impairment, hospitalization, or requiring intervention) were also recorded. RESULTS: A total of 112 patients were enrolled (mean age 44.1±17.6 years, 56.3% men), and 201 Apollo devices were used in 142 embolization procedures. The mean Spetzler-Martin grade was 2.38. The primary endpoint was not observed (0/112, 0%). The catheter tip detached during 83 (58.5%) procedures, of which 2 (2.4%) were unintentional and did not result in clinical sequelae. At 30 days, procedure related AEs occurred in 26 (23.2%) patients, and procedure-related serious AEs in 12 (10.7%). At 12 months, there were 3 (2.7%) mortalities, including 2 (1.8%) neurological deaths, none of which were device-related. CONCLUSION: This study demonstrates the safety of Apollo for Onyx embolization of bAVMs. CLINICAL TRIAL REGISTRATION: CNCT02378883.

STA-enhanced vascularized galeal flap for revascularization of moyamoya disease: technical report.

BACKGROUND: A variety of revascularization techniques have been reported for the management of moyamoya disease to prevent risks of stroke. STA (superficial temporal artery)-MCA (middle cerebral artery) microanastomosis, single or double bypass, with temporal muscle or galeal onlay graft has been the standard operative procedure. METHOD: Our rationale of revascularization surgery has been a combination of STA-MCA double bypass using the frontal and the parietal branches of STA and transfer of a highly vascularized thick galeal flap with maintained STA vasculature. CONCLUSION: This STA-enhanced vascularized galeal flap graft is extremely effective for revascularization of moyamoya disease.

Percutaneous Intervention for Left Ventricular Assist Device Outflow Obstruction.

Left ventricular assist devices (LVADs) are used to support patients with advanced systolic heart failure (HF). These patients might develop LVAD dysfunction and consequent HF symptoms. Occasionally, outflow graft obstruction is responsible for LVAD dysfunction. Here, we describe percutaneous techniques to repair the outflow graft and avoid re-sternotomy.

Novel Application of Steroid Eluting Stent in Petrous Apex Cholesterol Granuloma.

Objective This study describes the safety and efficacy of mometasone furoate eluting stents in the management of petrous apex cholesterol granuloma approached through an endonasal endoscopic route and assesses the restenosis rate. Methods Consecutive patients undergoing endoscopic endonasal marsupialization of a petrous apex cholesterol granuloma at a tertiary referral center who had a mometasone furoate eluting stent placed intraoperatively were reviewed in a retrospective fashion. Postoperative endoscopy was used to determine success of surgery and stenting. Results Five patients were included in the study, three were primary cases and two patients had revision surgeries performed. The steroid eluting stent was placed successfully and safely in all patients with no dural or vascular injuries. The average follow-up duration was 10.6 months. There was no restenosis in three patients and one patient had an immediate restenosis that was debrided in clinic (revision case). This was patent at the 16 months follow-up. One patient also developed stenosis, 4 months after surgery due to sphenoid sinusitis. Conclusion Mometasone furoate eluting stents are safe and effective in the primary management of petrous apex cholesterol granuloma. Further studies are needed to assess their efficacy in revision cases and for long term results.

Sinonasal Quality of Life Outcomes After Extended Endonasal Approaches to the Skull Base.

Introduction Endoscopic endonasal skull base surgery (EESBS) leads to significant alterations in sinonasal anatomy and physiology. However, there is limited data available on quality of life (QOL) outcomes following EESBS. Methods A retrospective review of patients undergoing EESBS from January 2014 to April 2017 was performed. Records were reviewed for clinical history, operative details, and 22-item Sinonasal Outcomes Test (SNOT-22) scores. Unadjusted and adjusted linear regression models were utilized to compare change in SNOT-22 scores from baseline in patients who underwent a simple sella approach (SA) or an extended beyond sella approach (BSA). Results A total of 108 patients were in the SA group, while 61 patients were in the BSA group. SNOT-22 scores were available at baseline and 3 months for 84 patients, while 6-month scores were available for 49 patients. SNOT-22 scores for all patients were not significantly different at 3 months ( p = 0.40) or at 6 months ( p = 0.58). Unadjusted linear regression model did not show an association between the type of approach and change in SNOT-22 score at 3 months ( p = 0.07) and 6 months ( p = 0.28). Adjusted regression model showed a significant decrease in SNOT-22 scores at 3 months ( p = 0.04) for the BSA group, but there was no significant change in SNOT-22 score at 6 months ( p = 0.22). Conclusion Patients undergoing EESBS had no significant change in outcomes at 3 and 6 months. A more extensive BSA was not associated with worse QOL outcomes as measured by SNOT-22.

Visualization of Dark Side of Skull Base with Surgical Navigation and Endoscopic Assistance: Extended Petrous Rhomboid and Rhomboid with Maxillary Nerve-Mandibular Nerve Vidian Corridor.

BACKGROUND: Lesions located at the petrous apex, cavernous sinus, clivus, medial aspect of the jugular foramen, or condylar regions are still difficult to fully expose using the operating microscope. Although approaches to this region through the middle cranial fossa have been previously described, these approaches afford only limited visualization. We have confirmed a transcranial infratemporal fossa combined microsurgical and endoscopic access to the petrous apex, clivus, medial aspect of the jugular foramen, and occipital condyle. We have presented the results of a micro-anatomical cadaver dissection study and its clinical application. METHODS: Ten latex-injected cadaveric specimens (20 twenty sides) underwent dissection with navigational guidance to achieve an extended anterior petrosal approach combined with a far vidian corridor approach (between the foramen rotundum and foramen ovale). We performed anatomical dissections to confirm the surgical anatomy and the feasibility and limitations of this approach. Anatomical dissections were performed in the skull base laboratory of Lariboisière Hospital and Duke University Medical Center. This approach was then applied to some clinical cases. RESULTS: The combination of the microscope and endoscope, aided by surgical navigation, was extremely effective and provided a wide view of the petrous rhomboid, the entire clivus, and the medial condylar regions. The extended extradural anterior petrosal approach provided a large corridor to petrous and clival lesions. Endoscopic assistance allows for wide and deep exposure of the middle to lower clivus, epipharyngeal space, and bilateral condylar regions. This approach successfully provided adequate surgical access for resection of tumors located in these regions. The depth of the medial aspect of the jugular foramen was 16.3 ± 1.2 mm deep from the geniculate ganglion. The emerging point of the inferior petrosal sinus in the jugular foramen was 16.5 ± 1.8 mm deep from the geniculate ganglion. The hypoglossal canal was 21.6 ± 2.2 mm deep from the geniculate ganglion. The foramen magnum was located 31.5 ± 2.4 mm deep from the gasserian ganglion. The inferior petrosal sinus was found to be a reliable landmark to identify the medial portion of the jugular bulb. The introduction of the endoscope through the middle fossa rhomboid enabled visualization of the medial aspect of the jugular bulb, which otherwise would be hampered by the internal auditory canal under the microscope. CONCLUSION: After microscopic exposure of the middle fossa rhomboid, neuronavigational endoscopic assistance facilitated visualization of the ventral cavernous region, petrous apex, retropharyngeal space, and middle and inferior clivus down to the medial aspect of the jugular bulb and condyle regions. Additional maxillary nerve-mandibular nerve vidian corridor visualization provides a lateral transsphenoidal approach to upper clivus lesions.

Endovascular management of spinal dural arteriovenous fistulas.

Spinal dural arteriovenous fistulas (dAVF) are the most common subset of the larger group of spinal vascular malformations. In this chapter, we discuss the definition, epidemiology, clinical presentation, diagnosis, treatment, and outcomes of spinal dAVF. Special attention is given to clinical approach, imaging, and diagnosis with discussion of newer spinal magnetic resonance angiographic techniques. Endovascular management techniques are discussed, including technical and safety considerations for the performance of spinal angiography and various methods of embolization. Embolization media, including liquid embolics, particles, and coils, are introduced. Finally, clinical and imaging outcomes are discussed with attention to the clinical and imaging findings of dAVF recurrence.

Carotid Endarterectomy to Remove Retained Solitaire Stent Retriever inside Carotid Stent after Mechanical Thrombectomy.

BACKGROUND: Tandem occlusions of the internal carotid artery (ICA) and middle cerebral artery (MCA) occur in up to a third of patients with acute ischemic strokes undergoing endovascular mechanical thrombectomy. Understanding open neurosurgical management of associated complications with this procedure is important. CASE REPORT: A 67-year-old man with acute onset of left hemiparesis and a tandem right ICA and MCA occlusion. He underwent carotid stent angioplasty of a stenotic ICA, followed by attempted Solitaire stent retrieval of an MCA clot. On withdrawal, the tines of the Solitaire stent lodged inside the Precise carotid stent. The patient was started on aspirin, Plavix, and heparin infusion, and underwent a carotid endarterectomy (CEA) with safe removal of the stents and primary vessel repair. CONCLUSION: This is the first case reported to date of a Solitaire stent becoming lodged inside a Precise carotid stent, salvaged by CEA with safe removal of the stents and primary vessel repair. We discuss the timing, indication, alternatives, and technical nuances of a CEA in this setting.

Rare Lesions of the Internal Auditory Canal.

BACKGROUND: Approximately 95% of tumors occurring within the internal auditory canal (IAC) are vestibular schwannomas. Many undergo stereotactic radiation without definitive tissue diagnosis. Rare IAC tumors are not all radiosensitive and are poorly described. METHODS: Between 1992 and 2015, 289 consecutive patients with IAC lesions operated on were reviewed retrospectively. RESULTS: Fifteen patients (5.2%) (16 operations) had unusual histologic findings, including nonvestibular schwannomas (2 facial schwannomas, 2 cochlear schwannomas, 2 intermedius schwannomas), 3 meningiomas, 3 cavernous hemangiomas, a mucosa-associated lymphoid tissue lymphoma, an arachnoid cyst, and a lipochoristoma. None of these rare tumors could be identified before surgery. Three operative approaches were used: the retrosigmoid approach, middle fossa subtemporal approach, or translabyrinthine approach. Few complications occurred, including facial nerve palsy, loss of hearing, and vestibular function. Five-year average follow-up revealed one patient with recurrence. CONCLUSIONS: Clinical examination and imaging alone were insufficient to correctly identify these tumors. Definitive pathologicdiagnosis should be strongly considered to help tailor treatment.

Optimal pediatric dosing of anti-platelet agents for pipeline stent embolization -a case report and review of the literature.

BACKGROUND: Various strategies are emerging for dosing antiplatelet therapies in preparation for pipeline stent embolization in adults. Hyper-response is associated with hemorrhagic complications. Hypo-response is associated with thromboembolic events. Dosing of antiplatelet agents is highly variable, with little consensus among experts for adults-and even more so for children. To date, pipeline stents have been deployed in 11 pediatric patients, ages 4-15. A variety of clopidogrel and aspirin dosing regimens have been used, with response tested in only three patients, who were all therapeutic. Thrombotic events occurred in two patients, neither of whom were tested. CASE: We describe here the first case of a hemorrhagic complication in a hyper-responsive pediatric patient undergoing placement of a pipeline stent. DISCUSSION: As the use of endovascular therapies requiring dual anti-platelet agents becomes more established, there is an increasing need to develop titration protocols that minimizes the risk of thrombotic and hemorrhagic events.