Faculty Bibliography

OBJECTIVE:While pedicled intranasal flaps, such as the nasoseptal flap (NSF), successfully reduce postoperative CSF leaks following endoscopic endonasal approaches (EEA) to the skull base, morbidity remains prevalent. This study describes the first cadaveric description and radiographic analysis of the posterior septal nasal floor mucosal flap (PSNF) designed to reduce pedicled nasal flap morbidity. A case series is also detailed. STUDY DESIGN:Cadaveric dissection, radiographic analysis, and case series. METHODS:Seven cadaver specimens underwent harvest of the PSNF. PSNF flap dimensions were measured on the thirty deidentified sinus computed tomography (CT) scans. A retrospective case series was performed on the first set of patients who received the PSNF for reconstruction of a sellar base defect. Information concerning complications, symptoms, and the appearance of the flap was recorded from records of the patient's postoperative inpatient stay, 1-week postop visit, and 1-month postop visit. RESULTS:, respectively. 15 patients underwent reconstruction of a sellar or planum defect using the PSNF technique. Only one CSF leak was encountered postoperatively. Minimal crusting of the flap and donor site was seen 1 month postoperatively. CONCLUSION:The PSNF flap provides a sizeable pedicled region for reconstruction comparable to other pedicled nasal flaps. Our case series demonstrated good postoperative outcomes without reduced donor site morbidity. LEVEL OF EVIDENCE:4 Laryngoscope, 132:1561-1568, 2022.

PURPOSE:Traditional endoscopic endonasal approaches to the cavernous sinus (CS) open the anterior CS wall just medial to the internal carotid artery (ICA), posing risk of vascular injury. This work describes a potentially safer midline sellar entry point for accessing the CS utilizing its connection with the inferior intercavernous sinus (IICS) when anatomically present. METHODS:The technique for the midline intercavernous dural access is described and depicted with cadaveric dissections and a clinical case. RESULTS:An endoscopic endonasal approach exposed the periosteal dural layer of anterior sella and CS. The IICS was opened sharply in midline through its periosteal layer. The feather knife was inserted and advanced laterally within the IICS toward the anterior CS wall, thereby gradually incising the periosteal layer of the IICS. The knife was turned superiorly then inferiorly in a vertical direction to open the anterior CS wall. This provided excellent access to the CS compartments, maintained the meningeal layer of the IICS and the medial CS wall, and avoided an initial dural incision immediately adjacent to the ICA. CONCLUSION:The midline intercavernous dural access to the CS assisted by a 90° dissector-blade is an effective modification to previously described techniques, with potentially lower risk to the ICA.

BACKGROUND:Trigeminal schwannomas (TSs) with solitary extracranial location are rare, and surgical excision is challenging. In recent years, the endoscopic endonasal transmaxillary transpterygoid approach (EETPA) has been advocated as an effective strategy for TSs in the infratemporal fossa (ITF). METHOD:We describe the steps of the EETPA combined with the sublabial transmaxillary approach for the surgical excision of a giant mandibular schwannoma of the ITF. Indications, advantages, and approach-specific complications are also discussed. The main surgical steps are shown in an operative video. CONCLUSION:A combined EETPA and sublabial transmaxillary approach represents a safe and effective option for the surgical excision of extracranial TSs.

BACKGROUND:The lingual process of the sphenoid bone (LP) and the petrolingual ligament (PLL) surround laterally the internal carotid artery within the middle cranial fossa (MCF). OBJECTIVE:To study the LP and the PLL and anatomical variations considering their relationships with different structures and landmarks within the MCF, especially oriented toward the endoscopic endonasal approaches. METHODS:Seventy-two sides of dry skulls and 20 sides of embalmed specimens were studied. The measurements of the LP and the PLL were obtained, considering important landmarks in the MCF. RESULTS:The LP had a mean length and height of 5 mm and 3 mm, respectively. Its distance from the foramen lacerum was 6 mm, from the foramen ovale 10 mm, foramen rotundum 15 mm, and petrous apex 9 mm. In 44 sides (61.11%), the LP partially closed the lateral aspect of the carotid sulcus; in 17 sides (23.61%), it was found as a near-ring; and in 11 sides (15.2%), it was considered rudimentary. Considering the PLL, its length and height were, respectively, 9 mm, and 4 mm. CONCLUSION:The LP and PLL separate the carotid artery at the inferior aspect of Meckel's cave and constitute important landmarks for endoscopic endonasal approaches to Meckel's cave and MCF, and their identification and removal is essential for internal carotid artery mobilization in this area.

OBJECTIVE:The aim of this study is to verify if the length of the nasoseptal flap is sufficient to cover the tuberculum sellae and planum sphenoidale of sphenoidal sinuses with varied degrees of pneumatization. METHODS:Retrospective study of paranasal sinus computed tomography comparing the potential length of the nasoseptal flap and the length of the nasoseptal flap required for reconstruction of transtuberculum and transplanum approaches in conchal, presellar, sellar, incomplete postsellar, and complete postsellar sphenoidal sinuses. RESULTS:The length of the nasoseptal flap required for reconstruction of transtuberculum and transplanum approaches was directly related to the degree of pneumatization of the sphenoidal sinus. The nasoseptal flap length was adequate to cover the cranial base after transtuberculum approaches of all cases from the conchal, presellar, and sellar groups and the majority of cases from postsellar pneumatization. For transplanum approaches, the nasosseptal flap was sufficient to reconstruct defects in most cases from conchal, pre-sellar, and sellar type sinuses and in 54,9% and 19,2% in incomplete and complete postsellar, respectively. CONCLUSIONS:In well pneumatized sphenoidal sinus, the nasoseptal flap may not be sufficient to cover the cranial base after transtuberculum and transplanum approaches.

OBJECTIVE:Esthesioneuroblastoma (ENB) is a rare malignant neoplasm arising from the olfactory epithelium of the cribriform plate. The goal of this study was to update our oncologic outcomes for this disease and explore prognostic factors associated with survival. MATERIALS AND METHODS:We performed a retrospective analysis of patients with ENB treated at a single tertiary care institution from January 1, 1960, to January 1, 2020. Univariate and multivariate analysis was performed. Overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS) were reported. RESULTS:Among 143 included patients, the 5-year OS was 82.3% and the 5-year PFS was 51.6%; 5-year OS and PFS have improved in the modern era (2005-present). Delayed regional nodal metastasis was the most common site of recurrence in 22% of patients (median, 57 months). On univariate analysis, modified Kadish staging (mKadish) had a negative effect on OS, PFS, and DMFS (p < 0.05). Higher Hyams grade had a negative effect on PFS and DMFS (p < 0.05). Positive margin status had a negative effect on PFS (p < 0.05). Orbital invasion demonstrated worsening OS (hazard ratio, 3.1; p < 0.05). On multivariable analysis, high Hyams grade (3 or 4), high mKadish stage (C+D), and increasing age were independent negative prognostic factors for OS (p < 0.05). High Hyams grade (3+4), high mKadish stage (C+D), age, and positive margin status were independent negative prognostic factors for PFS (p < 0.05). High Hyams grade (3+4) was an independent negative prognostic factor for DMFS (p < 0.05). CONCLUSIONS:Patients with low Hyams grade and mKadish stage have favorable 5-year OS, PFS, and DMFS.

BACKGROUND:The pedicled nasoseptal flap (NSF) is the mainstay for endoscopic skull base reconstruction. We present a novel technique using a semirigid chondromucosal NSF that improves the reinforcement and protection of intracranial structures. METHODS:Composite NSFs were performed to repair intraoperative high-flow cerebrospinal fluid leaks in 2 patients who had undergone endoscopic endonasal resection of a suprasellar mass. The surgical technique and postoperative outcomes are described. RESULTS:The flaps were sufficient for defect coverage, and the patients did not experience any cerebrospinal fluid leak in the immediate and delayed postoperative periods. No complications related to the composite flap had developed. CONCLUSIONS:The composite chondromucosal NSF is a reliable reconstruction option for select ventral cranial base reconstruction cases with the potential to improve the protection of intracranial structures. Additional surgical cases and longer follow-up are required for a better assessment of long-term outcomes.

BACKGROUND:The lateral craniopharyngeal or Sternberg's canal (SC) originates from superior orbital fissure (SOF) and traverses the sphenoid body into the nasopharynx. A remnant of the canal, Sternberg's defect (SD), has been debated as a source of cerebrospinal fluid (CSF) leak. The canal was described in 1888, and there is limited accurate visual illustration in the literature. OBJECTIVE:To provide a detailed anatomic and radiological illustration of the canal in pediatric and adult population including the mechanism undermining the incidence of the canal, and the possibility of the canal as a source of CSF leak. METHODS:A total of 195 high-resolution computed tomographies (CT) of patients (50 3-yr-old, 20 5-yr-old, and 125 adults) and 43 dry adult skulls (86 sides) were analyzed for a canal matching the description of the SC. RESULTS:A SC was identified in 86% of the 3-yr-old and 40% of 5-yr-old patients. The diameter and length were 2.12 mm and 12 mm, respectively. The incidence of the canal decreased with age as sinus pneumatization extended into the sphenoid sinus. Only 0.8% of the adult skull on CT had the canal. The canal was not present on the dry adult skulls examination, but SD was found in 4.65%. CONCLUSION:SC exists with high incidence in the pediatric group. Sinus pneumatization obliterates the canal in the adult population, leaving a defect in 4.65% of cases, which given the location and related anatomic structures, is unlikely to be a source of CSF leak.

BACKGROUND:Reconstruction of full thickness nasal defects usually requires different donor sites for the external skin envelope, structural elements, and internal nasal lining. In this paper we present a novel single site method for dual inner lining and skeleton repair for full thickness nasal defects with a composite nasoseptal flap and extended pedicle dissection. METHODS:A 72-year-old male presented with a T4b melanoma involving the nasal dorsum and left upper lateral cartilage. Following full thickness resection, reconstruction was performed with a nasoseptal flap (NSF) with attached septal cartilage and vomer in conjunction with a paramedian forehead flap. Extended pedicle dissection into the pterygopalatine fossa allowed the NSF to fully cover the defect. RESULTS:The nasal defect was fully corrected. There was no evidence of flap compromise or nasal valve stenosis at 1 month, 2 month, and 1 year follow-up visits. CONCLUSIONS:We present here the first successful application of a composite cartilage-osseous-mucosal NSF for multilayered nasal reconstruction. In appropriate patients, this technique may obviate the need for flaps or grafts from extranasal sources, limiting donor site morbidity.