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Objective: Minimally invasive endoscopic endonasal multiport approaches create additional visualization angles to treat skull base pathologies. The sublabial contralateral transmaxillary (CTM) approach and superior eyelid lateral transorbital approach, frequently used nowadays, have been referred to as the "third port" when used alongside the endoscopic endonasal approach (EEA). The endoscopic precaruncular contralateral medial transorbital (cMTO) corridor, on the other hand, is an underrecognized but unique port that has been used to repair CSF rhinorrhea originating from the lateral sphenoid sinus recess. However, no anatomical feasibility studies or clinical experience exists to assess its benefits and demonstrate its potential role in multiport endoscopic access to the other contralateral skull base areas. In this study, the authors explored the application and potential utility of multiport EEA combined with the endoscopic cMTO approach (EEA/cMTO) to three target areas of the contralateral skull base: lateral recess of sphenoid sinus (LRSS), petrous apex (PA) and petroclival region, and retrocarotid clinoidocavernous space (CCS)., Methods: Ten cadaveric specimens (20 sides) were dissected bilaterally under stereotactic navigation guidance to access contralateral LRSS via EEA/cMTO. The PA and petroclival region and retrocarotid CCS were exposed via EEA alone, EEA/cMTO, and EEA combined with the sublabial CTM approach (EEA/CTM). Qualitative and quantitative assessments, including working distance and visualization angle to the PA, were recorded. Clinical application of EEA/cMTO is demonstrated in a lateral sphenoid sinus CSF leak repair., Results: During the qualitative assessment, multiport EEA/cMTO provides superior visualization from a high vantage point and better instrument maneuverability than multiport EEA/CTM for the PA and retrocarotid CCS, while maintaining a similar lateral trajectory. The cMTO approach has significantly shorter working distances to all three target areas compared with the CTM approach and EEA. The mean distances to the LRSS, PA, and retrocarotid CCS were 50.69 ± 4.28 mm (p < 0.05), 67.11 ± 5.05 mm (p < 0.001), and 50.32 ± 3.6 mm (p < 0.001), respectively. The mean visualization angles to the PA obtained by multiport EEA/cMTO and EEA/CTM were 28.4° ± 3.27° and 24.42° ± 5.02° (p < 0.005), respectively., Conclusions: Multiport EEA/cMTO to the contralateral LRSS offers the advantage of preserving the pterygopalatine fossa contents and the vidian nerve, which are frequently sacrificed during a transpterygoid approach. This approach also offers superior visualization and better instrument maneuverability compared with EEA/CTM for targeting the petroclival region and retrocarotid CCS.

The styloid process constitutes the posterolateral boundary for an endonasal exposure of the infratemporal fossa. This study aims to explore the feasibility of a far-lateral extension to the lateral poststyloid space via an endonasal corridor. An endonasal dissection was performed on six cadaveric specimens (12 sides). Following an endoscopic endonasal access to the parapharyngeal space, the styloid process and the tympanic portion of the temporal bone were removed to reveal the jugular bulb and the extratemporal facial nerve. Distances from the anterior nasal spine to the relevant landmarks were measured using a surgical navigation device. Through an endonasal corridor, only the anteroinferior aspect of the jugular bulb was exposed. Conversely, the extratemporal facial nerve could be sufficiently exposed, and the deep temporal nerve could be transposed to the stylomastoid foramen. The average horizontal distances from the nasal spine to the posterior tract of V 3 , styloid process, and facial nerve were 79.33 ± 3.41, 97.10 ± 4.74, and 104.77 ± 4.42 mm, respectively. Access to the lateral poststyloid space via an endonasal corridor is feasible, potentially providing an alternative approach to address select lesions extending to this region. The deep temporal nerve has a similar diameter to that of the facial nerve; thus, providing potential reinnervation of the facial nerve., (© 2022 The Authors. Head & Neck published by Wiley Periodicals LLC.)

Background: Superb knowledge of surgical anatomy and nuances to remove the natural barriers preventing full access to the paramedian skull base determines the ease of using the expanded sellar/parasellar approaches as the main gateway for all the parasagittal modules during endoscopic endonasal access (EEA) to pituitary tumors with cavernous sinus (CS) invasion., Methods: Throughout stepwise-cadaveric dissections and pertinent intraoperative analysis, we describe surgical pearls and pitfalls of the parasellar-EEA with special references to the utility of various lines/classifications on neuroimaging correlated with strategies to enhance surgical safety and tumor resection., Conclusion: EEA to invasive parasellar pathologies needs to address strict bleeding control and displacement of neurovascular structures inside the CS, posing a chance for neurologic morbidities/ICA injury. Meticulous utilization of operative landmarks and strategies can help avoid and mitigate surgical complications.

Objective: The pediatric skull base may present anatomic challenges to the skull base surgeon, including limited sphenoid pneumatization and a narrow nasal corridor. The rare nature of pediatric skull base pathology makes it difficult to gain experience with these anatomic challenges. The objective of this study was to create a 3-dimensionally (3D) printed model of the pediatric skull base and assess its potential as a training tool., Methods: Twenty-eight participants at various stages of training and practice were included in our study. They completed a pre- and postdissection questionnaire assessing challenges with endoscopic endonasal skeletonization of the carotid arteries and sella face using the 3D printed model., Results: The majority of participants had completed a skull base surgery fellowship (60.7%), were <5 years into practice (60.7%), and had <10 cases of pediatric skull base experience (82.1%). Anticipated challenges included limitation of maneuverability of instruments (71.4%), narrow nasal corridor and nonpneumatized bone (57.1%). On a scale of 0-10, 10 being very difficult, the average participant expected level of difficulty with visualization was 6.89 and expected level of difficulty with instrumentation was 7.3. On postdissection assessment, there was a nonstatistically significant change to 6.93 and 7.5, respectively. Participants endorsed on a scale of 0-10, 10 being very realistic, an overall model realism of 7.0 and haptic realism of 7.1., Conclusions: A 3D printed model of the pediatric skull base may provide a realistic model to help participants gain experience with anatomic limitations characteristic of the pediatric anterior skull base., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Using the expanded endoscopic transtuberculum approach (EETA), the nuances of this technique have rendered a safe, direct, and feasible ventral corridor for the treatment of extending suprasellar pathologies. This study illustrates surgical landmarks and strategies of paramount importance for complications avoidance., Methods: This study presents the surgical anatomy and nuances of EETA, which can be used to remove large pituitary adenomas with suprasellar extension. Special references to cadaveric dissections highlight anatomical landmarks and surgical key points for complications avoidance., Conclusion: The EETA represents a versatile route for the treatment of sellar/suprasellar pathologies. Although, sizeable extrasellar pituitary tumors still pose a threat due to displacement/encasement of surrounding structures, necessitating accurate knowledge of correlative operative anatomy with traditional landmarks. Complete resection of extrasellar components is essential to avoid postoperative apoplexy.

Introduction: Since the early use of the endoscopic view for treating simple intrasellar pituitary adenomas, the skull base surgery has experienced an unprecedented revolution elevating the treatment of skull base lesions to the next level in proficiency and excellence of care., Methods: We have reviewed the preclinical and clinical evidence supporting the use of the endoscope in the treatment of skull base lesions. In this article, we aim to discuss and provide a wide view of the current indications and future perspectives of the endoscopic endonasal approaches (EEA) and of the endoscopic transcranial approaches., Results: As in the development of any other technique, EEA have gone through a transformation process from theoretical anatomic models to a pragmatic clinical use. Along the way, EEA have required several modifications, as well as pushbacks in the application of this technique in some indications. This process has resulted in the provision of an additional tool to the current surgical armamentarium that allows the skull base surgeon to face most challenging lesions along the skull base., Conclusions: The judicious combination of transcranial and endoscopic-transnasal approaches warrants highest chances of achieving satisfactory tumors resection with a reduced risk of complications.

Anterior skull base (ASB) malignancies are rare entities characterized by delayed diagnosis and comprise a variety of distinct histological types. Their treatment involves clinical and surgical management, with the latter encompassing open and, more recently, endoscopic approaches. The craniofacial resection, as an open approach, has revolutionized the treatment of such diseases and is the gold standard, although significant morbidity and facial scars are a shortcoming. Seeking a less invasive alternative, many surgeons have approached these pathologies using the endoscopic endonasal approach, with the theoretical advantage of reduced morbidity and no facial scars. In this manuscript, we aim to review the current state-of-art in the surgical management of the ASB malignancies. As such, indications, limitations and future perspectives of different surgical techniques are discussed.

Background: Endoscopic transethmoidal and prelacrimal approaches can access the medial intraconal space (MIS)., Objective: This study aimed to compare advantages and drawbacks of these two approaches, and to explore their appropriate indications for management of lesions at various locations within the MIS., Methods: Six injected cadaveric specimens were dissected using an endonasal approach performing a transethmoidal approach on one side and a prelacrimal approach on the contralateral side. The MIS was divided into three Zones : Zone 1 was defined as the area above the superior border of the medial rectus muscle (MRM), Zone 2 as the area between the MRM and the optic nerve, and Zone 3 as the area below the inferior border of MRM. The exposure provided by these two approaches to various Zones within the MIS was assessed and compared., Results: The average height of Zone 1 to 3 was 10.35 ± 0.45 mm, 11.07 ± 0.59 mm, and 6.53 ± 0.59 mm, respectively. Both approaches provided adequate exposure of Zone 2 and 3 ; however, the prelacrimal approach provided direct exposure of the posterosuperior aspect of Zone 2 without retraction of MRM. Retraction of MRM was unavoidable using a transethmoidal approach to enhance further exposure. Access to Zone 1 was adequately achieved through the corridor between superior oblique muscle and MRM via a transethmoidal corridor., Conclusion: Conceptualizing the MIS into the three aforementioned Zones seems beneficial to select the optimal approach for lesions restricted to each specific Zone. Both the transethmoidal and prelacrimal approaches provide adequate exposure for select lesions in the MIS.

Background: Expanded endonasal approaches can provide direct access to the midline skull base from the anterior cranial fossa to the ventral foramen magnum. Surgical strategies of bone drilling, dural opening, and intradural dissection can determine the area of surgical exposure and instrument handling, affecting the safety of devascularizing/debulking suprasellar tumors., Methods: We describe an expanded endoscopic endonasal approach for suprasellar lesions, with stepwise image-guided dissections highlighting surgical pearls and pitfalls to enhance surgical safety. This article presents transnasal intra-third-ventricular anatomy from trans-tuber cinereum, and trans-lamina terminalis approaches, comparing subchiasmatic and suprachiasmatic trajectories., Conclusion: The rostral extension via endoscopic endonasal transsellar-transtubercular-transplanum approaches can provide a safe and feasible route for suprasellar lesions, in subchiasmatic, suprachiasmatic, and intraventricular regions.

Background: Lesions of the upper parapharyngeal space (UPPS) present a surgical challenge. The objective of this study was to ascertain the feasibility of a novel technique of modified transpterygoid approach to the UPPS., Methods: Six fresh cadaveric specimens (12 sides) were dissected, developing a technique that includes en bloc mobilization of the lateral pterygoid plate and muscle to access the UPPS., Results: Following an endoscopic Denker's approach and the removal of posterolateral wall of the antrum, the lateral pterygoid plate was detached from the pterygoid process. Subsequently, the lateral pterygoid plate and muscle were displaced laterally as a unit, allowing the identification of the posterior trunk of V 3 and the fat in prestyloid compartment. Dissecting off the styloid aponeurosis affords entering the poststyloid UPPS exposing the internal carotid artery, internal jugular vein, and cranial nerves IX to XII., Conclusion: This novel modification of the endonasal transpterygoid approach offers a viable alternative for access to the UPPS., (© 2020 Wiley Periodicals, Inc.)

Objectives/hypothesis: Patients are frequently advised to sneeze with an open mouth and avoid nose-blowing following an endoscopic endonasal approache (EEA) to the skull base, despite a lack of quantitative evidence. This study applies computational fluid dynamics (CFD) to quantify sinus pressures along the skull base during sneezing., Study Design: Case-control series., Methods: Computed tomography or magnetic resonance imaging scans of four post-EEA patients and four healthy controls were collected and analyzed utilizing CFD techniques. A pressure drop of 6,000 Pa was applied to the nasopharynx based on values in the literature to simulate expiratory nasal airflow during sneezing. Peak pressures along the skull base in frontal, ethmoid, and sphenoid sinuses were collected., Results: Significant increases in skull base peak pressure was observed during sneezing, with significant individual variations from 2,185 to 5,685 Pa. Interestingly, healthy controls had significantly higher pressures compared to post-EEA patients (5179.37 ± 198.42 Pa vs. patients 3,347.82 ± 1,472.20 Pa, P < .05), which could be related to higher anterior nasal resistance in unoperated healthy controls (0.44 ± 0.22 vs. 0.31 ± 0.16 Pa/mL/sec for patients, P = .38). The sinus pressure buildup may be due to airway resistance functioning as a valve preventing air from being released quickly. Supporting this theory, there was a strong correlation (r = 0.82) between peak skull base pressure and the ratio of anterior resistance to total resistance. Within-subject variation in pressures between different skull base regions was much lower (average = ~5%)., Conclusions: This study provided the first quantitative analysis of air pressure along the skull base during sneezing in post-EEA patients through CFD, suggesting that pressure buildup may depend on individual anatomy., Level of Evidence: 3b Laryngoscope, 130:2138-2143, 2020., (© 2019 The American Laryngological, Rhinological and Otological Society, Inc.)

Importance: Injury to the internal carotid artery (ICA) during endoscopic endonasal skull base surgery does not typically occur as an isolated circumstance but often is the result of multiple factors., Objective: To assess the factors associated with ICA injury in an effort to reduce its occurrence., Design, Setting, and Participants: This quality improvement study used a multicenter root cause analysis of ICA injuries sustained during endoscopic endonasal skull base surgery performed at 11 tertiary care centers across 4 continents (North America, South America, Europe, and Asia) from January 1, 1993, to December 31, 2018. A fishbone model was built to facilitate the root cause analysis. Patients who underwent an expanded endoscopic endonasal approach that carried a substantial potential risk of an ICA injury were included in the analysis. A questionnaire was completed by surgeons at the centers to assess relevant human, patient, process, technique, instrument, and environmental factors associated with the injury., Main Outcomes and Measures: Root cause analysis of demographic, human, patient, process, technique, instrument, and environmental factors as well as mortality and morbidity data., Results: Twenty-eight cases of ICA injury occurred during 7160 expanded endoscopic endonasal approach procedures (incidence of 0.4%). The mean age of the patients was 49 years, with a female to male predominance ratio of 1.8:1 (18 women to 10 men). Anatomical (23 [82%]), pathological (15 [54%]), and surgical resection (26 [93%]) factors were most frequently reported. The surgeon's mental or physical well-being was reported as inadequate in 4 cases (14%). Suboptimal imaging was reported in 6 cases (21%). The surgeon's experience level was not associated with ICA injury. The ICA injury was associated with use of powered or sharp instruments in 20 cases (71%), and use of new instruments or technology in 7 cases (25%). Two patients (7%) died in the operating room, and 3 (11%) were alive with neurological deficits. Overall, patient-related factors were the most frequently reported risk factors (in 27 of 28 cases [96%]). Factors associated with ICA injury catalyzed a list of preventive recommendations., Conclusions and Relevance: This study found that human factors were associated with intraoperative ICA injuries; however, they were usually accompanied by other deficiencies. These findings suggest that identifying risk factors is crucial for preventing such injuries. Preoperative planning and minimizing the potential for ICA injury also appear to be essential.

Objective: The ventral jugular foramen and the infrapetrous region are difficult to access through conventional lateral and posterolateral approaches. Endoscopic endonasal approaches to this region are obstructed by the eustachian tube (ET). This study presents a novel strategy for mobilizing the ET while preserving its integrity. Qualitative and quantitative comparisons with previous ET management paradigms are also presented., Methods: Ten dry skulls were analyzed. Four ET management strategies were sequentially performed on a total of 6 sides of cadaveric head specimens. Four measurement groups were generated: in group A, the ET was intact and not mobilized; in group B, the ET was mobilized inferolaterally; in group C, the ET underwent anterolateral mobilization; and in group D, the ET was resected. ET range of mobilization, surgical exposure area, and surgical freedom were measured and compared among the groups., Results: Wide exposure of the infrapetrous region and jugular foramen was achieved by removing the pterygoid process, unroofing the cartilaginous ET up to the level of the posterior aspect of the foramen ovale, and detaching the ET from the skull base and soft palate. Anterolateral mobilization of the ET facilitated significantly more retraction (a 126% increase) of the ET than inferolateral mobilization (mean ± SD: 20.8 ± 11.2 mm vs 9.2 ± 3.6 mm [p = 0.02]). Compared with group A, groups C and D had enhanced surgical exposure (142.5% [1176.9 ± 935.7 mm2] and 155.9% [1242.0 ± 1096.2 mm2], respectively, vs 485.4 ± 377.6 mm2 for group A [both p = 0.02]). Furthermore, group C had a significantly larger surgical exposure area than group B (p = 0.02). No statistically significant difference was found between the area of exposure obtained by ET removal and anterolateral mobilization. Anterolateral mobilization of the ET resulted in a 39.5% increase in surgical freedom toward the exocranial jugular foramen compared with that obtained through inferolateral mobilization of the ET (67.2° ± 20.5° vs 48.1° ± 6.7° [p = 0.047]) and a 65.4% increase compared with that afforded by an intact ET position (67.2° ± 20.5° vs 40.6° ± 14.3° [p = 0.03])., Conclusions: Anterolateral mobilization of the ET provides excellent access to the ventral jugular foramen and infrapetrous region. The surgical exposure obtained is superior to that achieved with other ET management strategies and is comparable to that obtained by ET resection.

Background: Endoscopic skull-base surgery (ESBS) is employed in the management of diverse skull-base pathologies. Paralleling the increased utilization of ESBS, the literature in this field has expanded rapidly. However, the rarity of these diseases, the inherent challenges of surgical studies, and the continued learning curve in ESBS have resulted in significant variability in the quality of the literature. To consolidate and critically appraise the available literature, experts in skull-base surgery have produced the International Consensus Statement on Endoscopic Skull-Base Surgery (ICAR:ESBS)., Methods: Using previously described methodology, topics spanning the breadth of ESBS were identified and assigned a literature review, evidence-based review or evidence-based review with recommendations format. Subsequently, each topic was written and then reviewed by skull-base surgeons in both neurosurgery and otolaryngology. Following this iterative review process, the ICAR:ESBS document was synthesized and reviewed by all authors for consensus., Results: The ICAR:ESBS document addresses the role of ESBS in primary cerebrospinal fluid (CSF) rhinorrhea, intradural tumors, benign skull-base and orbital pathology, sinonasal malignancies, and clival lesions. Additionally, specific challenges in ESBS including endoscopic reconstruction and complication management were evaluated., Conclusion: A critical review of the literature in ESBS demonstrates at least the equivalency of ESBS with alternative approaches in pathologies such as CSF rhinorrhea and pituitary adenoma as well as improved reconstructive techniques in reducing CSF leaks. Evidence-based recommendations are limited in other pathologies and these significant knowledge gaps call upon the skull-base community to embrace these opportunities and collaboratively address these shortcomings., (© 2019 ARS-AAOA, LLC.)

Objective: The authors previously described a graded approach to skull base repair following endonasal microscopic or endoscope-assisted tumor surgery. In this paper they review their experience with skull base reconstruction in the endoscopic era., Methods: A retrospective review of a single-institution endonasal endoscopic patient database (April 2010–April 2017) was undertaken. Intraoperative CSF leaks were graded based on size (grade 0 [no leak], 1, 2, or 3), and repair technique was documented across grades. The series was divided into 2 epochs based on implementation of a strict perioperative antibiotic protocol and more liberal use of permanent and/or temporary buttresses; repair failure rates and postoperative meningitis rates were assessed for the 2 epochs and compared., Results: In total, 551 operations were performed in 509 patients for parasellar pathology, including pituitary adenoma (66%), Rathke’s cleft cyst (7%), meningioma (6%), craniopharyngioma (4%), and other (17%). Extended approaches were used in 41% of cases. There were 9 postoperative CSF leaks (1.6%) and 6 cases of meningitis (1.1%). Postoperative leak rates for all 551 operations by grade 0, 1, 2, and 3 were 0%, 1.9%, 3.1%, and 4.8%, respectively. Fat grafts were used in 33%, 84%, 97%, and 100% of grade 0, 1, 2, and 3 leaks, respectively. Pedicled mucosal flaps (78 total) were used in 2.6% of grade 0–2 leaks (combined) and 79.5% of grade 3 leaks (60 nasoseptal and 6 middle turbinate flaps). Nasoseptal flap usage was highest for craniopharyngioma operations (80%) and lowest for pituitary adenoma operations (2%). Two (3%) nasoseptal flaps failed. Contributing factors for the 9 repair failures were BMI ≥ 30 (7/9), lack of buttress (4/9), grade 3 leak (4/9), and postoperative vomiting (4/9). Comparison of the epochs showed that grade 1–3 repair failures decreased from 6/143 (4.1%) to 3/141 (2.1%) and grade 1–3 meningitis rates decreased from 5 (3.5%) to 1 (0.7%) (p = 0.08). Prophylactic lumbar CSF drainage was used in only 4 cases (< 1%), was associated with a higher meningitis rate in grades 1–3 (25% vs 2%), and was discontinued in 2012. Comparison of the 2 epochs showed increase buttress use in the second, with use of a permanent buttress in grade 1 and 3 leaks increasing from 13% to 55% and 32% to 76%, respectively (p < 0.001), and use of autologous septal/keel bone as a permanent buttress in grade 1, 2, and 3 leaks increasing from 15% to 51% (p < 0.001)., Conclusions: A graded approach to skull base repair after endonasal surgery remains valid in the endoscopic era. However, the technique has evolved significantly, with further reduction of postoperative CSF leak rates. These data suggest that buttresses are beneficial for repair of most grade 1 and 2 leaks and all grade 3 leaks. Similarly, pedicled flaps appear advantageous for grade 3 leaks, while CSF diversion may be unnecessary and a risk factor for meningitis. High BMI should prompt an aggressive multilayered repair strategy. Achieving repair failure and meningitis rates lower than 1% is a reasonable goal in endoscopic skull base tumor surgery.

Objectives/hypothesis: To evaluate the potential of a minimally invasive transoral-transpalatal approach (MITA) to the retrocarotid petrous apex, as an adjunct to endoscopic endonasal approaches (EEAs)., Study Design: Cadaver study., Methods: Five cadaveric specimens were dissected raising an inverted U-shaped palatal mucoperiosteal flap, and drilling a rectangular palatotomy (between the greater palatine foramens, and just anterior to the palatine aponeurosis). This allowed a transpterygoid EEA with cross-court access (contralateral line of sight), followed by an extradural clivectomy that exposed the petroclival junction bilaterally. Surgical targets were marked on the posterior and medial surface of the petrous internal carotid artery (ICA), at its anterior genu, midhorizontal portion, and posterior genu. For each target and approach, the surgical freedom and angles of approach (in the horizontal and vertical planes) were calculated and statistically compared., Results: Compared to EEA, the MITA resulted in greater surgical freedom for all targets, with the highest values at the anterior genu (1,661.37 mm 2 vs. 312.76 mm 2 , P <.001), and maintaining superiority in this regard all the way to the posterior genu (847.84 mm 3 vs. 138.91 mm 3 , P < .005). MITA also offered greater angles of approach for all targets., Conclusions: This study suggests that the MITA may be indicated to supplement the exposure provided by a transpterygoid EEA. This technique, associated with low potential morbidity, offers an alternative to internal carotid lateralization while managing extradural lesions that are adjacent to the petrous ICA., Level of Evidence: NA Laryngoscope, 129:339-343, 2019., (© 2018 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: The catastrophic and rare nature of an internal carotid artery (ICA) injury during endonasal surgery limits training opportunities. Cadaveric and animal simulation models have been proposed, but expense and complicated logistics have limited their adoption. Three-dimensional (3D) printed models are portable, modular, reusable, less costly, and proven to improve psychomotor skills required for managing different lesions. In this study we evaluate the role of a simplified laser-sintered model combined with standardized training in improving the effectiveness of managing an ICA injury endoscopically., Methods: A 3-mm defect was created in the parasellar carotid canal of a laser-sintered model representing a sphenoid sinus. Artificial blood was directed to simulate the copious bleeding arising from an ICA injury. Twenty otolaryngologists and 26 neurosurgeons, with varying training and experience levels, were individually asked to stop the "bleeding" as they would in a clinical scenario, and provided no other instructions. This was followed by individualized formative training and a second simulation. Volume of blood loss, time to hemostasis, and self-assessed confidence scores were compared., Results: At the end of the study, time to hemostasis was reduced from 105.49 seconds to 40.41 seconds (p < 0.001). The volume of blood loss was reduced from 690 to 272 mL (p < 0.001), and the confidence scores increased in 95.7% of participants, from an average of 3 up to 8., Conclusion: This ICA injury model, along with a formal training algorithm, appears to be valuable, realistic, portable, and cost-effective. Significant improvement in all parameters suggests the acquisition of psychomotor skills required to control an ICA injury., (© 2018 ARS-AAOA, LLC.)

Ligation of the sphenopalatine and posterior nasal arteries is indicated for posterior epistaxis as initial treatment or when conservative measures fail. In some patients, a transnasal approach or its alternative transantral approach are not possible due to tumor filling the nasal corridor, pterygopalatine fossa, or maxillary sinus. Aim of this study was to evaluate feasibility of endoscopically assisted transoral approach for the ligation of the maxillary artery (MA). Six fresh cadaver specimens (12 sides), previously prepared with intravascular injections of colored latex, were dissected. A combined transnasal and transoral approach exposed the MA from the deep belly of the temporalis muscle laterally to its terminal branches medially. Anatomical relationships of the MA with the deep belly of the temporalis muscle and the lower head of the lateral pterygoid muscle, and feasibility of access to the MA via a transoral approach were assessed. In all specimens, the MA was found at the point where horizontal fibers of the lower head of the lateral pterygoid muscle cross the vertical fibers of the deep belly of the temporalis muscle. In 5 specimens, the artery ran anteriorly and laterally to lower head of the lateral pterygoid muscle, and in 1 specimen, it ran posteriorly and medially to this muscle, diving between its fibers. The modified endoscopically assisted transoral approach is feasible to ligate the MA. It can be used for proximal vascular control in cases when transnasal and transantral approaches are not viable.

Background: When locoregional flaps fail to reconstruct the skull base, the microvascular surgeon faces several reconstructive challenges. We present our technique and results of salvage anterior skull base reconstruction utilizing the vastus lateralis free tissue transfer (VLFTT)., Methods: Four patients with anterior skull base defects after previous locoregional flap failure underwent free tissue transfer reconstruction with VLFTT., Results: The success rate of free tissue transfer was 100%. Complete separation of the intracranial and sinonasal cavities was achieved in all patients; thus, resolving the cerebrospinal fluid (CSF) leakage in all patients. The VLFTT was inset through a minimally invasive approach utilizing an anterior maxillotomy via a gingivobuccal incision, an endoscopic medial maxillectomy, and endoscopic inset in all patients. No vein grafts were needed., Conclusion: This technique permits endoscopic endonasal inset and placement of reliable, well vascularized free tissue that may be utilized for complex, secondary reconstruction of the skull base., (© 2018 Wiley Periodicals, Inc.)

The authors describe the surgical anatomy for the endoscopic endonasal approach (EEA) to the ventrolateral skull base. The ventrolateral skull base can be divided into two segments: the upper lateral and lower lateral skull base. The upper lateral skull base includes the cavernous sinus and the orbit, while the lower lateral skull base includes the petrous apex, Meckel's cave, parapharyngeal space, infratemporal fossa, etc. To gain access to the upper lateral skull base, a simple opening of the ethmoid sinus provides sufficient exposure of this area. To reach the lower lateral skull base, a transpterygoid approach, following ethmoidectomy, is a key procedure providing wide exposure of this area. Understanding of surgical anatomy is mandatory for treating ventrolateral skull base lesions via EEA. An appropriate, less-invasive approach should be applied depending on the size, location, and type of lesion.

Background: The optic canal is a bony channel that connects the anterior cranial fossa and orbit and contains the optic nerve and ophthalmic artery. It can be affected by several pathologies, leading to compression of the nerve nearby or inside the canal, leading to visual impairment. The usual technique to decompress the canal is through a craniotomy, but recently endoscopic endonasal approaches (EEAs) have surfaced as an interesting alternative due to direct access to the canal without the need for manipulation of neurovascular structures., Methods: Six specimens were dissected. The right optic canal was drilled on the right side via the EEA, and the left optic canal was drilled via frontotemporal craniotomy. The amount of decompression was measured using a 3-dimensional reconstruction on computed tomography scans and compared., Results: The EEA generated an average of 267.8 (221-294) degrees of decompression in the anterior portion of the canal versus 258.3 (219-300) degrees of decompression in the posterior portion of the canal, whereas the craniotomy generated an average of 229.3 (101-289) degrees of decompression in the anterior portion of the canal versus 250.3 (76-300) degrees of decompression in the posterior portion of the canal. There was no significant difference statistically., Conclusion: The decision for an approach for optic canal decompression should be based on the site of the pathology and localization of canal involvement. Both techniques are equivalent in terms of proportion of nerve decompression., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objectives: As the adoption of endoscopic endonasal approaches (EEA) continues to proliferate, increasing numbers of internal carotid artery (ICA) injuries are reported. The objective of this study was to develop a synthetic ICA injury-training model that could mimic this clinical scenario and be portable, repeatable, reproducible, and without risk of biological contamination., Methods: Based on computed tomography of a human head, we constructed a synthetic model using selective laser sintering with polyamide nylon and glass beads. Subsequently, the model was connected to a pulsatile pump using 6-mm silicon tubing. The pump maintains a pulsatile flow of an artificial blood-like fluid at a variable pressure to simulate heart beats. Volunteer surgeons with different levels of training and experience were provided simulation training sessions with the models. Pre- and posttraining questionnaires were completed by each of the participants., Results: Pre- and posttraining questionnaires suggest that repeated simulation sessions improve the surgical skills and self-confidence of trainees., Conclusion: This ICA injury model is portable; reproducible; and avoids ethical, biohazard, religious, and legal problems associated with cadaveric models. A synthetic ICA injury model for EEA allows recurring training that may improve the surgeon's ability to maintain endoscopic visualization, control catastrophic bleeding, decrease psychomotor stress, and develop effective team strategies to achieve hemostasis., Level of Evidence: NA Laryngoscope, 127:38-43, 2017., (© 2016 The American Laryngological, Rhinological and Otological Society, Inc.)

Petroclival meningiomas are challenging lesions to manage independently of the selected surgical approach and are unique tumors in the type of pathological displacement of the surrounding anatomy. They also represent one of the most controversial entities with regard to approach selection, especially when deciding between an open versus endonasal route. When choosing an approach to the intradural portion of the petroclival region, the location of critical neurovascular structures relative to the lesion must be anticipated, including the abducens and trigeminal nerves. The role of the expanded endoscopic endonasal approach (EEA) in the management of ventral posterior fossa meningiomas is still restricted due to limited surgical indications in selected cases. It is a safe alternative for the rare cases of meningiomas with most part of its dural base at the midline clival region, and it may be used as solely or combination of other approaches. Thus, appropriate case selection may optimize the advantages of the approach and reduce morbidity of this complex pathology. We discuss in this review article the main advantages and limitations of the EEA for clival and petroclival meningiomas.

OBJECTIVE The endoscopic endonasal approach (EEA) offers direct access to midline skull base lesions, and the anterior transpetrosal approach (ATPA) stands out as a method for granting entry into the upper and middle clival areas. This study evaluated the feasibility of performing EEA for tumors located in the petroclival region in comparison with ATPA. METHODS On 8 embalmed cadaver heads, EEA to the petroclival region was performed utilizing a 4-mm endoscope with either 0° or 30° lenses, and an ATPA was performed under microscopic visualization. A comparison was executed based on measurements of 5 heads (10 sides). Case illustrations were utilized to demonstrate the advantages and disadvantages of EEA and ATPA when dealing with petroclival conditions. RESULTS Extradurally, EEA allows direct access to the medial petrous apex, which is limited by the petrous and paraclival internal carotid artery (ICA) segments laterally. The ATPA offers direct access to the petrous apex, which is blocked by the petrous ICA and abducens nerve inferiorly. Intradurally, the EEA allows a direct view of the areas medial to the cisternal segment of cranial nerve VI with limited lateral exposure. ATPA offers excellent access to the cistern between cranial nerves III and VIII. The quantitative analysis demonstrated that the EEA corridor could be expanded laterally with an angled drill up to 1.8 times wider than the bone window between both paraclival ICA segments. CONCLUSIONS The midline, horizontal line of the petrous ICA segment, paraclival ICA segment, and the abducens nerve are the main landmarks used to decide which approach to the petroclival region to select. The EEA is superior to the ATPA for accessing lesions medial or caudal to the abducens nerve, such as chordomas, chondrosarcomas, and midclival meningiomas. The ATPA is superior to lesions located posterior and/or lateral to the paraclival ICA segment and lesions with extension to the middle fossa and/or infratemporal fossa. The EEA and ATPA are complementary and can be used independently or in combination with each other in order to approach complex petroclival lesions.

Background: The quadrangular space permits an anterior entry into Meckel's cave while obviating the need for cerebral or cranial nerve retraction. This avenue is intimately associated with the cavernous sinus; thus, from this ventral perspective, it is feasible to visualize the anteromedial, anterolateral, and Parkinson triangles., Methods: Twenty middle cranial fossae were dissected endonasally under direct endoscopic visualization. Measurements of the surface area of the quadrangular space and the ventrally accessible cavernous sinus triangles were performed using 3 coordinates under image-guided navigation., Results: The surface area of the quadrangular space was 16.36 mm(2) (±2.89 mm(2) ). The anterolateral triangle was the largest (47.27 ± 5.37 mm(2) ), whereas Parkinson's was the smallest (22.46 ± 5.54 mm(2) ); the anteromedial triangle presented an average surface area 36.07 mm(2) (±4.15 mm(2) )., Conclusion: The trajectory of the internal carotid artery (ICA) significantly impacts the quadrangular space area and may be a potential parameter for defining the feasibility of this corridor. © 2016 Wiley Periodicals, Inc. Head Neck 38: E1680-E1687, 2016., (© 2016 Wiley Periodicals, Inc.)

Injury of the internal carotid artery during endoscopic endonasal skull base surgery is a feared and perilous scenario. This article discusses perioperative strategies to prevent or manage an internal carotid artery injury to optimize outcomes. Meticulous preoperative planning is crucial in preventing its occurrence and minimizing its consequences. An effective plan of action relies on a well-prepared protocol, availability of proper instruments and devices, and an experienced multidisciplinary team. Intraoperative control of hemorrhage and stabilization of the patient's cardiovascular status is followed by an angiography and endovascular treatment whenever possible. Close clinical and radiologic monitoring of the patient prevents early and late complications., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Object: Despite the widespread adoption of endoscopic transsphenoidal surgery for pituitary adenomas, the sinonasal quality of life (QOL) and health status in patients who have undergone this technique have not been compared with these findings in patients who have undergone the traditional direct uninostril microsurgical technique. In this study, the authors compared the sinonasal QOL and patient-reported health status after use of these 2 surgical techniques., Methods: The study design was a nonblinded prospective cohort study. Adult patients with sellar pathology and planned transsphenoidal surgery were screened at 4 pituitary centers in the US between October 2011 and August 2013. The primary end point of the study was postoperative patient-reported sinonasal QOL as measured by the Anterior Skull Base Nasal Inventory-12 (ASK Nasal-12). Supplementary end points included patient-reported health status estimated by the 8-Item Short Form Health Survey (SF-8) and EuroQol (EQ)-5D-5L instruments, and sinonasal complications. Patients were followed for 6 months after surgery., Results: A total of 301 patients were screened and 235 were enrolled in the study. Of these, 218 were analyzed (111 microsurgery patients, 107 endoscopic surgery patients). Demographic and tumor characteristics were similar between groups (p ≥ 0.12 for all comparisons). The most common complication in both groups was sinusitis (7% in the microsurgery group, 13% in the endoscopic surgery group; p = 0.15). Patients treated with the endoscopic technique were more likely to have postoperative nasal debridements (p < 0.001). The ASK Nasal-12 and SF-8 scores worsened substantially for both groups at 2 weeks after surgery, but then returned to baseline at 3 months. At 3 months after surgery, patients treated with endoscopy reported statistically better sinonasal QOL compared with patients treated using the microscopic technique (p = 0.02), but there were no significant differences at any of the other postoperative time points., Conclusions: This is the first multicenter study to examine the effect of the transsphenoidal surgical technique on sinonasal QOL and health status. The study showed that surgical technique did not significantly impact these patient-reported measures when performed at high-volume centers. Clinical trial registration no.: NCT01504399 ( clinicaltrials.gov ).

Objectives/hypothesis: This cadaveric study analyzes the endoscopic endonasal anatomy of the ophthalmic division of the trigeminal nerve (V1 ), from the middle fossa to its orbital entry via the superior orbital fissure. Anatomical relationships with the surrounding cranial nerves and blood vessels are described, with emphasis on their clinical correlation during surgery in this region. Our objective was to describe the anatomical relationships of the ophthalmic division of the trigeminal nerve., Study Design: Cadaveric study., Methods: Thirty middle cranial fossae, in adult human cadaveric specimens, were dissected endonasally under direct endoscopic visualization. During the dissection, we noted the relationships of the V1 nerve with the other trigeminal branches, as well as with the oculomotor and trochlear nerves, the paraclival and cavernous portions of the internal carotid artery, and the superior orbital fissure (SOF)., Results: The V1 nerve is the most superior trigeminal branch and runs upward and obliquely, along the middle portion of the lateral wall of the cavernous sinus. The V1 nerve joins the oculomotor and trochlear nerves to exit the cavernous sinus and enter the orbit through the SOF. Ten percent of the specimens displayed the trochlear nerve running along as a mate of the V1 nerve. The V1 nerve borders two key triangles in the lateral wall of the cavernous sinus, and the Parkinson's and anteromedial triangles., Conclusions: In this study, the V1 nerve was a constant and reliable landmark, thus allowing the identification of the anteromedial triangle. This potential space can serve as an adequate window to access the temporal lobe. Knowledge of this anatomy is essential when planning and executing endonasal surgery in this region., Level of Evidence: NA., (© 2014 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: The anatomy of the skull base is extremely complex with an abundance of critical neurovascular bundles and their corresponding foramina as well as the insertions and origins of multiple masticatory and craniocervical muscles. These anatomic intricacies increase the difficulty of surgery within this area., Methods: Advantages and disadvantages of endoscopic endonasal approaches (EEAs) based on the authors' sequential learning and experience are described., Results: EEAs offer the advantages of using preexistent air spaces that enable accessing various areas of the skull base, while avoiding external incisions or scars and obviating the need for the translocation of the maxillofacial skeleton. In addition, EEAs are well suited to preserve neurologic, visual, and masticatory functions as well as cosmesis. However, the sinonasal corridor must be expanded and optimized to access the skull base adequately, facilitate the reconstruction of the surgical defect, avoid sinonasal complications, and minimize sequelae. Important considerations can limit or indicate the approach, such as the nature of the pathology, including location, diagnosis, and vascularity; patient characteristics, including age and medical comorbidities; surgeon attributes, including training, experience, and expertise; the resultant need to reconstruct large skull base defects and feasible alternatives to do so; and institutional resources, including adjunctive services, an intensive care unit, and operating room equipment., Conclusions: EEAs are important techniques in contemporary skull base surgery. Understanding the indications for and limitations of these approaches help to maximize outcomes., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Objective: To describe the technical and anatomic nuances related to endoscopic endonasal approaches (EEAs) to the paramedian skull base., Methods: Surgical indications, limitations, and technical aspects pertaining to EEAs designed to access areas oriented in the coronal plane are systematically reviewed with special attention to caveats, pitfalls, and common complications and how to avoid them. Case examples are presented., Results: The paramedian skull base may be divided into anterior (corresponding to the orbit and its contents), middle (corresponding to the middle cranial, pterygopalatine, and infratemporal fossae), and posterior (includes the craniovertebral junction lateral to the occipital condyles and the jugular foramen) segments. EEAs to the anterior segment offer access to the intraconal orbital space and the optic canal. A transpterygoid corridor typically precedes EEAs to the middle and posterior paramedian approaches. EEAs to the middle segment provide wide exposure of the petrous apex, middle cranial fossa (including cavernous sinus and Meckel cave), and infratemporal and pterygopalatine fossae. Finally, EEAs to the posterior segment access the hypoglossal canal, occipital condyle, and jugular foramen., Conclusions: Approaches to the paramedian skull base are the most challenging and complex of all endoscopic endonasal techniques. Because of their technical complexity, it is recommended that surgeons master endoscopic endonasal anatomic approaches oriented to median structures (sagittal plane) before approaching paramedian (coronal plane) pathologies., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Objectives/hypothesis: To define transnasal endoscopic surgical landmarks for the parapharyngeal segment of the internal carotid artery (ppICA) using radiographic analysis and cadaveric dissection., Study Design: Cadaveric and radiographic study., Methods: One hundred seventy-nine computed tomography angiography studies of the head and neck were analyzed using Osirix third-party software (Pixmeo, Geneva, Switzerland). Dissection of a cadaveric specimen was used as a correlate to radiographic findings. The posterior aspect of the lateral pterygoid process and posterior border of the mandibular ramus were used as bony landmarks for the ppICA., Results: At the level of the nasal floor, the distance from the ppICA to the posterolateral pterygoid process and to the posterior mandibular ramus was 2.36 cm and 1.94 cm, respectively, in males, and 2.37 cm and 1.99 cm, respectively, in females. At the level of the skull base, the distance from the ppICA to the posterolateral pterygoid process and to the posterior mandible was 2.33 cm and 1.49 cm, respectively, in males, and 2.20 cm and 1.57 cm, respectively, in females. Cadaver dissection demonstrated the utility of identifying these landmarks., Conclusions: The posterior border of the mandibular ramus and the posterolateral aspect of the pterygoid process may serve as consistent bony landmarks for identification of the ppICA., (© 2014 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: The purpose of this study was to describe the incidence of the middle ethmoidal artery and its anatomical nuances via an endoscopic endonasal approach., Methods: A cadaveric study was performed on 22 adult specimens. First, a frontal sinusotomy and ethmoidectomy were performed via an endoscopic endonasal approach in order to fully expose the anterior skull base. Subsequently, the lamina papyracea and the bone of the canals covering the ethmoidal neurovascular bundles were removed to identify the anterior, middle, and posterior ethmoidal arteries. Presence, laterality, and location of the middle ethmoidal artery were recorded., Results: A total of 14 middle ethmoidal arteries were identified (10 right and 4 left), among 44 sides (22 specimens), accounting for an incidence of 31.8%. Bilateral middle ethmoidal arteries were found in 3 of 22 specimens (14%). Endonasal endoscopy features of the middle ethmoidal artery were noted., Conclusion: This is the first study assessing the anatomical features of the middle ethmoidal arteries from an endonasal endoscopic perspective. The findings of this research have clinical significance in guiding surgeries that involve the medial orbital wall, intractable epistaxis, and anterior skull base pathologies, as well as endoscopic endonasal surgeries., (© 2013 ARS-AAOA, LLC.)

Endoscopic expanded endonasal approaches (EEAs) to the skull base are increasingly being used to address a variety of skull base pathologies. Postoperative CSF leakage from the large skull base defects has been well described as one of the most common complications of EEAs. There are reports of associated formation of delayed subdural hematoma and tension pneumocephalus from approximately 1 week to 3 months postoperatively. However, there have been no reports of immediate complications of high-volume CSF leakage from EEA skull base surgery. The authors describe two cases of EEAs in which complications related to rapid, large-volume CSF egress through the skull base surgical defect were detected in the immediate postoperative period. Preventive measures to reduce the likelihood of these immediate complications are presented.

Object: Skull base chondrosarcomas are slow-growing, locally invasive tumors that arise from the petroclival synchondrosis. These characteristics allow them to erode the clivus and petrous bone and slowly compress the contents of the posterior fossa progressively until the patient becomes symptomatic, typically from cranial neuropathies. Given the site of their genesis, surrounded by the petrous apex and the clival recess, these tumors can project to the middle fossa, cervical area, and posteriorly, toward the cerebellopontine angle (CPA). Expanded endoscopic endonasal approaches are versatile techniques that grant access to the petroclival synchondrosis, the core of these lesions. The ability to access multiple compartments, remove infiltrated bone, and achieve tumor resection without the need for neural retraction makes these techniques particularly appealing in the management of these complex lesions., Methods: Analysis of the authors' database yielded 19 cases of skull base chondrosarcomas; among these were 5 cases with predominant CPA involvement. The electronic medical records of the 5 patients were retrospectively reviewed for age, sex, presentation, pre- and postoperative imaging, surgical technique, pathology, and follow-up. These cases were used to illustrate the surgical nuances involved in the endonasal resection of CPA chondrosarcomas., Results: The male/female ratio was 1:4, and the patients' mean age was 55.2 ±11.2 years. All cases involved petrous bone and apex, with variable extensions to the posterior fossa and parapharyngeal space. The main clinical scenario was cranial nerve (CN) palsy, evidenced by diplopia (20%), ptosis (20%), CN VI palsy (20%), dysphagia (40%), impaired phonation (40%), hearing loss (20%), tinnitus (20%), and vertigo/dizziness (40%). Gross-total resection of the CPA component of the tumor was achieved in 4 cases (80%); near-total resection of the CPA component was performed in 1 case (20%). Two patients (40%) harbored high-grade chondrosarcomas. No patient experienced worsening neurological symptoms postoperatively. In 2 cases (40%), the symptoms were completely normalized after surgery., Conclusions: Expanded endoscopic endonasal approaches appear to be safe and effective in the resection of select skull base chondrosarcomas; those with predominant CPA involvement seem particularly amenable to resection through this technique. Further studies with larger cohorts are necessary to test these preliminary impressions and to compare their effectiveness with the results obtained with open approaches.

Background: Pituitary adenomas are often encased in a histological pseudocapsule that separates the tumor from the normal gland. Transsphenoidal adenoma resection may be performed either in an intra- or an extracapsular technique. The extracapsular fashion offers anatomical orientation, removal of a security margin, reduced risk of opening the arachnoid layer with subsequent CSF flow and identification of invasion., Method: The sella turcica is approached through the classic endoscopic endonasal route. After opening the dura of the sellar floor, the interface between the compressed tissue and the normal gland is used as a surgical plane for dissection. Performing slight counter-traction with the suction tube, the cleavage plane is identified and stepwise unsealed in an atraumatic fashion with the cotton swab. Once the cleavage plane is partially loosened, repeated twisting movements are performed with the cotton swab to enucleate the pseudocapsule and adenoma., Conclusion: Both micro- and macroadenomas presenting a pseudocapsule may be resected in the extracapsular dissection technique with the cotton swab. Operating in an endoscopic three- to four hands technique enables to visualize the anatomic planes and perform twisting movements with the cotton swab separating pseudocapsule and tumor in order to enucleate the adenoma.

Background: Intraoperative navigation is an important tool used during endonasal surgery, which typically requires rigid head fixation. Herein we describe a navigational technique using an autoregistration mask without head fixation., Material and Methods: Prospective evaluation of a surface autoregistration mask used without rigid head fixation in 12 consecutive endonasal endoscopic skull base procedures was performed with patients positioned in a horseshoe head holder. We assessed the accuracy by recording the surface registration error (SRE) and target registration error (TRE). We also noted the time required for installation and the occurrence of system failure. The system's accuracy was validated using a deep target simultaneously viewed with endoscopic., Results: In 12 consecutive endonasal cases performed by a neurosurgeon and ENT team, pathologies included pituitary macroadenomas (9), chordoma (1), craniopharyngioma (1), and sinonasal melanoma (1). Median time required for the registration and accuracy verification was 84 seconds (interval 64 to 129 seconds). The mask stayed on the patient throughout the procedure. The mean SRE was 0.8 mm (interval 0.6 to 0.9 mm). The mean TRE was 0.9 ± 0.7 mm and 1.0 ± 0.8 mm measured respectively at the beginning and end of the case. In every case, the system was judged accurate by the surgical team using the sphenoid keel or an intrasphenoidal bony septation as a deep target for internal validation. No system failure occurred during these 12 cases., Conclusion: A facial surface autoregistration mask maintained in place throughout surgery without rigid head fixation allows excellent operational accuracy in endonasal pituitary and skull base surgery. This navigation system is practical, reliable, and noninvasive., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Object: Symptomatic sellar arachnoid cysts (ACs) have typically been treated via the transsphenoidal route. After sellar cyst wall fenestration, some authors have advocated cyst wall resection and increasing communication between the AC and suprasellar subarachnoid space (SAS). This study is a report of the authors' experience using a simplified approach to reinforce a defective diaphragma sellae or unseen arachnoid diverticulum by deliberately not enlarging the AC-SAS communication and obliterating the cyst cavity with adipose tissue followed by skull base reconstruction., Methods: A retrospective analysis was conducted of patients who underwent an endonasal transsphenoidal obliteration of symptomatic ACs with a fat graft and skull base repair., Results: Between July 1998 and September 2010, 8 patients with a sellar AC were identified (6 women and 2 men, mean age 57 years). Clinical presentation included headache, pituitary dysfunction, and visual dysfunction (4 patients each group). Maximal cyst diameter averaged 22 mm (range 15-32 mm). In all cases the sellar communication to the SAS was deliberately not enlarged. The endoscope was used for visualization in 8 of 9 procedures. Postoperatively, headache improved in all 4 patients, vision in all 4 patients, and partial resolution of endocrine dysfunction (hyperprolactinemia and/or recurrent hyponatremia) occurred in 3 (75%) of 4 patients. No new endocrinopathy, CSF leak, meningitis, or neurological deficits occurred. Two patients experienced cyst reaccumulation: 1 symptomatic recurrence was treated with reoperation at 43 months postsurgery, and 1 asymptomatic partial recurrence continued to be monitored at 29 months postsurgery., Conclusions: Sellar ACs can be effectively treated using endonasal fenestration and obliteration with fat with resultant reversal of presenting symptoms in the majority of patients. This simplified technique of AC cavity obliteration without enlarging communication to the SAS has a low risk of CSF leakage, and in most cases appears to effectively disrupt cyst progression, although longer follow-up is required to monitor for cyst recurrence.

Background: The infratemporal fossa anatomy, from an endoscopic standpoint, is poorly understood. Our purpose was to design an anatomic model that illustrates the anatomy of the infratemporal fossa from the endoscopic standpoint and serves as a training model for surgeons interested in pursuing this endeavor., Methods: Red and blue silicone dyes were respectively injected into the great vessels of the neck. Digital data acquired from a high resolution CT scan was imported to a navigational system. An endoscopic endonasal dissection of the infratemporal fossa was completed under conditions that mimicked our operating suite., Results: A detailed anatomic dissection of the infratemporal fossa was correlated to the image guidance (navigation) system. This provided a surgical map highlighting critical neurovascular structures and illustrating the potential surgical corridors., Conclusion: A thorough understanding of the anatomy of infratemporal fossa from the endoscopic perspective allows the surgeon to plan an adequate corridor., (Copyright © 2011 Wiley Periodicals, Inc.)

Objectives/hypothesis: The aim of this work was to define the anatomical landmarks, limitations, and difficulties of obtaining internal carotid artery (ICA) exposure via endonasal endoscopic approaches (EEA)., Study Design: Cadaveric descriptive study., Methods: The ICA was dissected via EEA in 10 cadaveric specimens (20 sides) prepared with intravascular injections of colored silicone. We carried the ICA dissection from the cavernous to the distal parapharyngeal segments through a transpterygoid corridor., Results: The transpterygoid approach provided adequate exposure of the lacerum and horizontal petrous ICA. Additional exposure of the ICA and the infrapetrous area required resection of the eustachian tube (ET) and the fibrocartilaginous tissue of the foramen lacerum after a medial maxillectomy and resection of the pterygoid plates. The main anatomical landmarks to the corresponding ICA segment include: the vidian nerve that points to the lacerum and horizontal segments, the mandibular nerve (V3) that heralds the petrous segment, the foramen ovale and the ET that signal toward the carotid canal, and the posterior trunk of the mandibular nerve (V3) and the ET that mark the parapharyngeal segment., Conclusions: EEAs provide access to the ICA from its cavernous to the distal parapharyngeal segments. A stepwise approach is critical to its exposure and control. Surgeons must be aware of its frequently tortuous three-dimensional course and the intimate relation of the vessel to the carotid canal and the cartilage of the foramen lacerum., (Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.)

Objectives/hypothesis: To describe the clinical presentation, pathophysiology, and treatment of spontaneous cerebrospinal fluid (CSF) leaks of the sphenoid bone, with an emphasis on a previously undescribed form in this location, in which CSF is trapped under the mucosa of the sinonasal cavity or in the soft tissue of the skull base., Study Design: Case series and literature review., Methods: Analysis of cases through medical records and literature review., Results: Four examples of unusual spontaneous CSF leaks of the skull base are presented. In each case, a CSF collection was contained behind the sinonasal mucosa of the sphenoid sinus, resembling a nasal polyp or mucocele on exam or imaging. In one case, the fluid collection was also associated with significant bone resorption and extravasation into the soft tissue of the infratemporal fossa. In each case, small defects of the ventral skull base (sphenoid bone) were the source of the CSF leaks. Successful treatment was achieved after transnasal endoscopic repair of the skull base defects using a combination of free abdominal fat grafts, free fascial grafts, and pedicled nasoseptal flaps. Postoperatively, a ventriculoperitoneal shunt was placed if the intracranial pressure was elevated., Conclusions: Spontaneous CSF leaks arising in the sphenoid sinus may not always present with overt CSF rhinorrhea but with a submucosal fluid collection (pseudomeningocele) that may mimic a mucocele or nasal polyp. These bona fide pseudomeningoceles of the skull base may be associated with elevated intracranial pressure and can be managed using endoscopic endonasal surgery., (Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.)

Background: Indications for expanded endoscopic approaches continue to grow, resulting in larger and more complex skull base defects. Reconstructive developments, however, have lagged our extirpative capabilities. As the complexity of clinical scenarios continues to escalate, challenging our current reconstructive strategies, we are compelled to develop alternative techniques to prevent cerebrospinal fluid leaks and protect neurovascular structures. In this article we show the anatomic basis for a new posterior pedicled flap from the lateral wall of the nose (Carrau-Hadad [C-H] flap) for the reconstruction of median skull base defects and present our early clinical experience., Methods: Using a cadaveric model, we designed a posterior pedicle flap comprising the nasal inferolateral wall mucoperiosteum. We applied this information clinically, to reconstruct transmural skull base defects., Results: In our cadaveric model, we harvested and transposed C-H flaps into various defects of the planum sphenoidale, sella turcica, clivus, and nasopharynx. Then, we used the C-H flap in four patients, successfully reconstructing their clival (n = 3) and sellar (n = 1) surgical defects. All patients healed uneventfully., Conclusion: Our anatomic study and early clinical experience support the use of the posterior pedicle lateral nasal wall flap to reconstruct large cranial base defects resulting from endoscopic skull base surgery in properly selected patients.

Objective: Describe our technique for endoscopic transpterygoid nasopharyngectomy and support its feasibility with our early clinical outcomes., Methods: Our endoscopic technique comprises an extended inferomedial maxillectomy, mobilization of the pterygopalatine fossa, removal of the pterygoid plates and Eustachian tube to access the posterolateral nasopharynx. Control of the parapharyngeal and petrous segments of the internal carotid artery is the keystone of the approach., Results: Various histopathologies were treated, including epidermoid carcinomas (n = 9), lymphoepithelioma (n = 1), adenoid cystic carcinoma (n = 5), adenocarcinoma (n = 2), mucoepidermoid carcinoma (n = 2), and sarcoma (n = 1). Negative microscopic margins were obtained in 95% (19/20) of patients. No perioperative mortality, cerebral spinal fluid (CSF) leak, meningitis, or cerebrovascular accident was encountered; however, one patient suffered an internal carotid artery (ICA) injury, without permanent sequelae. All but one patient received adjuvant therapy (external and/or stereotactic radiotherapy with or without chemotherapy). Follow-up ranged from 15 to 68 months (mean = 33). Overall survival was 45% (9/20) and local control was 65% (13/20)., Conclusions: Endoscopic transpterygoid nasopharyngectomy for primary and recurrent nasopharyngeal malignancies is feasible and safe in properly selected patients. Preliminary outcomes compare to that of conventional techniques. Endoscopic resections, however, are demanding; they require specialized equipment and a team versed in endoscopic oncologic surgery. Long-term follow-up and reproducibility remain undefined., (Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.)

Background: Nasal morbidity following skull base surgery necessitates follow-up for postoperative care. We describe nasal morbidity following endoscopic skull base surgery., Methods: Patient and operative data and postoperative subjective and objective measures of morbidity were prospectively collected for 1 year. Time to absence of crusting and remucosalization were determined. Risk factor analyses for crusting and nasal discharge were performed., Results: Nasal crusting (98%) and discharge (46%) were the most common postoperative symptoms. Median time to absence of crusting was 101.0 days, with longer times for complex cases (p = .033) but not for patients with septal flaps or fat grafts. Median time to remucosalization after nasoseptal flap was 89.0 days. There were no risk factors for crusting, although surgical complexity was a risk factor for postoperative discharge (odds ratio [OR] = 5.17)., Conclusions: Nasal morbidity following endoscopic skull base surgery is common and may be affected by surgical complexity and use of the nasoseptal flap., (Copyright © 2010 Wiley Periodicals, Inc.)

Background: Endonasal endoscopic skull base surgery (ESBS) is perceived as having a high risk of infection because it is performed through the sinuses, which are not sterile., Objective: To identify the bacteriological characteristics, incidence, mortality, and risk factors for intracranial infection after ESBS., Methods: A retrospective analysis of the first 1,000 ESBS procedures performed at the University of Pittsburgh Medical Center from 1998 to 2008., Results: In 18 cases (1.8%), the patient developed meningitis. In 2 cases, the patient died within 2 months after surgery, of noninfectious causes. In 11 cases, cerebrospinal fluid (CSF) cultures had positive results. There were no predominant pathogens. Male sex (odds ratio [OR], 3.97 [95% confidence interval {CI}, 1.21-13.03]; P = .02), history of a craniotomy or endonasal surgery (OR, 4.77 [95% CI, 1.68-13.56]; P = .02), surgery with higher levels of complexity (OR, 6.60 [95% CI, 1.77-24.70]; P = .003), the presence of an external ventricular drain or ventriculoperitoneal shunt at the time of surgery (OR, 6.38 [95% CI, 1.07-38.09]; P = .005), and postoperative CSF leak (OR, 12.99 [95% CI, 4.24-39.82]; P < .001) were risk factors for infection., Conclusion: The incidence of infection of 1.8% in ESBS is comparable to that in open craniotomy. The most important risk factor was a postoperative CSF leak. All patients recovered from their infection.

Objectives/hypothesis: To provide a description of the techniques and limitations of nasoseptal flap takedown and reuse during second-stage and revision endoscopic skull base surgery and review the institutional experience with the use of this reconstructive technique., Study Design: : Case series., Methods: A retrospective analysis of cerebrospinal fluid (CSF) leak outcomes was performed for a consecutive series of patients who underwent the nasoseptal flap takedown technique during endoscopic skull base surgery at two tertiary care skull base centers., Results: Twenty-eight consecutive cases with nasoseptal flap takedown procedures for endoscopic skull base reconstruction were collected and evaluated for flap viability and CSF leak outcomes. This cohort was composed of 14 revision surgeries and 14 planned second-stage procedures. There were no cases of flap loss. Twenty cases involved the presence of intraoperative CSF leaks. Twelve of these 20 cases were second-stage surgeries, and eight were revision or recurrent-tumor procedures. Nineteen of 20 had successful skull base reconstruction without a postoperative CSF leak. One patient required revision endoscopic CSF leak repair and bolstering of the defect with a fat graft 3 days after the initial surgery. Endoscopic skull base reconstructive techniques and limitations of flap takedowns are discussed., Conclusions: Expansion of the limits of endoscopic skull base surgery must be accompanied by the development of new reconstructive options. This report illustrates the ability to take down and reuse the nasoseptal flap in staged and revision cases with a high success rate and minimal additional nasal morbidity.

Objectives: Endoscopic endonasal approaches to the pterygopalatine and infratemporal fossae are technically challenging due to the complex anatomy of these areas. This project attempts to develop an anatomic and surgical model to enhance the understanding of these spaces from the endonasal endoscopic perspective., Methods: Eight pterygopalatine and infratemporal fossae were dissected in four adult human specimens in accordance with institutional protocols. All specimens were prepared with vascular injections using colored latex. Both the pterygopalatine and infratemporal fossae were accessed using a transpterygoid approach, which included a medial maxillectomy. Rod lens endoscopes (with 0°, 30°, and 45° lenses), surgical microscope, microsurgical and endoscopic instruments were used to complete the dissections., Results: Endoscopic endonasal approaches provided adequate access to the pterygopalatine and infratemporal fossae. Dissection of the internal maxillary artery and its terminal branches, and detachment of the medial and lateral pterygoid muscles were critical steps to access deeper structures of the infratemporal fossa. The lateral pterygoid plate was the most useful landmark to locate foramen ovale, and the mandibular branch of the trigeminal nerve. The Eustachian tube, medial pterygoid plate, and styloid process were the most useful landmarks to locate parapharyngeal poststyloid structures (parapharyngeal segment of the internal carotid artery, internal jugular vein, cranial nerves IX and X)., Conclusions: A medial maxillectomy coupled with a transpterygoid endoscopic approach, provides adequate access to the pterygopalatine and infratemporal fossae. The complex anatomy of the infratemporal fossa requires precise identification of surgical landmarks to assure preservation of neurovascular structures.