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BACKGROUND: The ability to reconstruct large cranial base defects has greatly improved with the development of pedicled vascularized flaps. The temporoparietal fascia flap (TPFF) is a viable alternative to the Hadad-Bassagasteguy nasoseptal flap for large ventral skull-base defects. This study aims to characterize the size of the TPFF necessary for optimal ventral skull-base reconstruction. METHODS: Eleven formaldehyde-fixed cadaveric heads were used to harvest TPFF of varying heights on each side (total = 22). TPFF was passed through the pterygomaxillary fissure (PMF) to the ventral skull base to assess its coverage. For a subgroup of 12 sides, the TPFF was trimmed to determine the minimum height necessary for coverage. RESULTS: The TPFF height was (mean ± standard deviation [SD]) 14.72 ± 1.02 cm (range, 12.5 to 16.5 cm) and width was 8.43 ± 1.05 cm (range, 6 to 10.5 cm). The distance from the TPFF pedicle through the PMF was 5.8 ± 0.5 cm (range, 5 to 6.5 cm). All TPFF flaps provided complete ipsilateral coverage of clival defects, and all but 1 covered the entire clivus. All TPFF flaps, when rotated anteriorly, provided coverage up to the cribriform plate. The minimum TPFF height necessary for complete coverage of cribriform defects and ventral defects up to the planum sphenoidale was 12 cm. TPFF height for specimens with and without complete ventral skull-base coverage was significantly different (p < 0.0001). CONCLUSION: The TPFF is a versatile alternative to the nasoseptal flap and a height of at least 12 cm can provide enough coverage for all ventral skull base defects.

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BACKGROUND: There remains considerable variation in the extent of sinonasal preservation during the approach for endoscopic transsphenoidal hypophysectomy (TSH). We advocate for a minimally destructive approach utilizing turbinate lateralization, small posterior septectomy, no ethmoidectomy, and preservation of nasoseptal flap (NSF) pedicles bilaterally. Due to these factors, this approach may affect the rates of postoperative rhinosinusitis. The objective of this study is to define the rates of postoperative rhinosinusitis in patients undergoing this approach. METHODS: Single institution, retrospective chart review of patients undergoing TSH from 2005 to 2018. RESULTS: A total of 415 patients were identified and 14% developed an episode of postoperative rhinosinusitis within 3 months. These patients were significantly more likely to have had a history of recurrent acute or chronic rhinosinusitis. Most cases were sphenoethmoidal sinusitis managed with 1 to 2 courses of antibiotics. Of patients with postoperative rhinosinusitis, most did not undergo NSF. Average follow-up was 38 months. Six patients (1.4%) underwent post-TSH functional endoscopic sinus surgery (FESS). Average time from TSH to FESS was 26.3 months. Two of these patients had a history of prior chronic rhinosinusitis without polyposis. Two patients underwent revision TSH for recurrent tumor as the primary indication for surgery at time of FESS. Twenty-two-item Sino-Nasal Outcome Test (SNOT-22) scores generally increased immediately postoperatively, but frequently decreased below preoperative level by the time of last follow-up, regardless of whether patients developed rhinosinusitis. CONCLUSION: Sinonasal preservation during TSH is associated with a low rate of postoperative rhinosinusitis requiring FESS and excellent long-term patient reported outcomes. We continue to advocate for sinonasal preservation during pituitary surgery.

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BACKGROUND: As the management of ventral skull-base pathology has transitioned from open to endonasal treatment, there has been an increased focus on the prevention and endoscopic endonasal management of internal carotid artery (ICA) and major vascular injury. The use of adenosine to induce transient hypotension or flow arrest has been previously described during intracranial aneurysm surgery; however, there have been no reports of the technique being used during endonasal skull-base surgery to achieve hemostasis following major vascular injury. METHODS: Case report (n = 1) and literature review. RESULTS: A 25-year-old female underwent attempted endoscopic endonasal resection of an advanced right-sided chondrosarcoma. During resection of the tumor, brisk arterial bleeding was encountered consistent with focal injury to the right cavernous ICA. Stable vascular hemostasis could not be achieved with tamponade. An intravenous bolus dose of adenosine was administered to induce a transient decrease in systemic blood pressure and facilitate placement of the muscle patch over the direct site of vascular injury. The patient subsequently underwent endovascular deconstruction of the right ICA. CONCLUSION: This is the first reported use of adenosine to induce transient hypotension for a major vascular injury sustained during endonasal skull-base surgery. Based on well-established safety data from neurosurgical application, adenosine has the potential to be used as a safe and effective adjunctive technique in similar endonasal circumstances and may represent an additional tool in the armamentarium of the skull-base surgeon. Surgeons should consider having adenosine available when a risk of ICA injury is anticipated.

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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.

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BACKGROUND: Although recent guidelines for obstructive sleep apnea recommend early postoperative use of continuous positive airway pressure (CPAP) after endonasal skull base surgery, the time of initiation of CPAP is unclear. In this study we used a novel, previously validated cadaveric model to analyze the pressures delivered to the cranial base and evaluate the effectiveness of various repair techniques to withstand positive pressure. METHODS: Skull base defects were surgically created in 3 fresh human cadaver heads and repaired using 3 commonly used repair techniques: (1) Surgicel™ onlay; (2) dural substitute underlay with dural sealant onlay; and (3) dural substitute underlay with nasoseptal flap onlay with dural sealant. Pressure microsensors were placed in the sphenoid sinus and sella, both proximal and distal to the repair, respectively. The effectiveness of each repair technique against various CPAP pressure settings (5-20 cm H2 O) was analyzed. RESULTS: Approximately 79%-95% of positive pressure administered reached the sphenoid sinus. Sellar pressure levels varied significantly across the 3 repair techniques and were lowest after the third technique. "Breach" points (CPAP settings at which sellar repair was violated) were lowest for the first group. All 3 specimens showed a breach after the first repair technique. For the second repair technique, only a single breach was created in 1 specimen at 20 cm H2 O. No breaches were created in the third group. CONCLUSION: Different skull base repair techniques have varying ability to withstand CPAP. Both second and third repair techniques performed in a nearly similar fashion with regard to their ability to withstand positive pressure ventilation.

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BACKGROUND: Obstructive sleep apnea is a common respiratory disorder that can have negative effects on health and quality of life. Positive pressure therapy (CPAP) is the primary treatment. There is a lack of consensus on the risk of postoperative CPAP after endoscopic sinus or skull base surgery. We present a proof-of-concept cadaver model for measuring sinonasal pressure delivered by CPAP. METHODS: Three fresh cadaver heads were prepared by removing the calvaria and brain. Sphenoidotomies were made and sellar bone was removed. Pressure sensors were placed in the midnasal cavity, sphenoid sinus, and sella. CPAP was applied and the delivered pressure was recorded at increasing levels of positive pressure. Paired t tests and intraclass correlation coefficients were used to analyze results. RESULTS: Increases in positive pressure led to increased pressure recordings for all locations. Nasal cavity pressure was, on average, 81% of delivered CPAP. Pressure was highest in the sphenoid sinus. The effect of middle turbinate medialization on intrasphenoid pressure was not statistically significant in 2 heads. Intrasellar pressure was 80% of delivered CPAP with lateralized turbinates and 84% with medialized turbinates. Pressure recordings demonstrated excellent reliability for all locations. All heads developed non-sellar-based cranial base leaks at higher pressures. Cribriform region leaks were successfully sealed with DuraSeal®. CONCLUSION: Our proof-of-concept cadaver model represents a novel approach to measure pressures delivered to the nasal cavity and anterior skull base by CPAP. With further study, it may have broader clinical application to guide the safe postoperative use of CPAP in this population.

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The purpose of this study was to evaluate the effect of posterior septectomy size on surgical exposure and surgical freedom during the endoscopic transsphenoidal approach to the sella and parasellar region. Dissections were performed on 10 embalmed cadaver heads. Dissections started with wide bilateral sphenoidotomies, lateralization of middle turbinates, and a 5-mm posterior septectomy. The posterior septectomy was increased in 5-mm increments to a maximum of 35 mm, followed by bilateral middle turbinectomies. Surgical exposure was defined as the distance between the ipsilateral and contralateral limit of exposure as allowed by the posterior septum along a midsphenoid horizontal meridian. Surgical freedom was defined as the angle between the ipsilateral and contralateral limit. The mean baseline width of the posterior sphenoid sinus was 29.4 ± 3.7 mm. With a 5-mm septectomy, the mean width of surgical exposure was 21.1 ± 2.8 mm. The surgical exposure increased significantly with progressively larger posterior septectomy until a 20-mm posterior septectomy, after which no further increase in surgical exposure or freedom was obtained. Bilateral lateral opticocarotid recesses were accessible with a 15-mm posterior septectomy. The addition of bilateral middle turbinectomies did not significantly increase lateral exposure within the sphenoid sinus compared with middle turbinate lateralization.

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BACKGROUND: Endoscopic-endonasal skull base surgery (ESBS) provides an important approach to select pathologies. There remains a paucity of data, however, regarding morbidity in patients undergoing ESBS with comorbid acute rhinosinusitis (ARS), a fungal ball (FB), or chronic rhinosinusitis (CRS). METHODS: A retrospective database review between January 2008 and January 2013 identified 35 patients with concurrent skull-base pathology and refractory ARS, FB, CRS, and CRS with nasal polyposis (CRSP) who underwent endoscopic sinus surgery (ESS) and ESBS. RESULTS: Two of 35 (5.7%) had an FB, 3 of 35 (8.6%) had ARS, 19 of 35 (54.2%) had CRSP, and 11 of 35 (31.4%) had CRS. Five of 35 (14.3%) were staged procedures whereas 30 of 35 (85.7%) underwent concurrent ESS and ESBS. Four patients (80%) who were staged carried diagnoses of an FB and ARS. Two patients in the concurrent group required revision ESS for recurrent polyposis. There were no cases of intraorbital or intracranial infectious complications. CONCLUSION: Management of the paranasal sinuses is paramount to maintain healthy sinonasal function in patients undergoing ESBS. In our experience, most cases of CRS and CRSP can be surgically managed at the time of ESBS without increased risk of intracranial infection. Patients with ARS at the time of surgery or an FB should be staged to avoid postoperative ESBS morbidity.

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BACKGROUND: The nasoseptal flap (NSF) has been shown to be a valuable addition to the reconstructive armamentarium of the endoscopic skull-base surgeon. We aimed to evaluate the rate of postoperative cerebrospinal fluid (CSF) leak after use of a NSF that had a small tear during harvest. METHODS: After Institutional Review Board (IRB) approval, we analyzed our database of patients undergoing skull-base resection. We included all patients who had a NSF reconstruction, septoplasty, and/or spur on preoperative computed tomography (CT) imaging. We then evaluated video of each procedure to determine if a tear occurred in the NSF during harvest. Patient records were reviewed to determine if a postoperative CSF leak occurred. RESULTS: We evaluated video of 21 patients who underwent a skull-base resection, were reconstructed with a NSF, and had either a septoplasty or evidence of a septal spur on CT imaging. Of these 21 cases, 11 small tears occurred during harvest of the NSF flap and none of the patients with a torn NSF had a postoperative CSF leak. CONCLUSION: Our series shows a 0% postoperative CSF leak rate in patients undergoing skull-base reconstruction with a NSF that was torn during harvest. Small tears in the NSF do not seem to affect postoperative CSF leak rates.

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