Endoscopic Transoral Approach for Resection of Basal Cell Adenoma Arising in Parapharyngeal Space

Anatomical Variations of the Ascending Pharyngeal Artery: Implications for Endoscopic Surgery in the Parapharyngeal Space

Objectives: The ascending pharyngeal artery (APA) travels with the parapharyngeal internal carotid artery (pICA) in the parapharyngeal space (PPS). This study aimed to investigate the anatomical variations of the APA, and to explore their implications for endoscopic surgery in the PPS. Methods: Dissection of the APA in the PPS was performed on 10 cadaveric specimens (20 sides). The relationship between APA and PPS tumors was retrospectively reviewed in 20 patients, attempting to ascertain the APA during the resection of 10 pre-styloid and 10 retro-styloid PPS tumors. Results: During the cadaveric dissections, the APA was identified at the medial, posteromedial, or bilateral aspects of the pICA in 12 (60%) and 4 (20%) sides, respectively. In the remaining 4 sides (20%), the APA branched into several subcategory arteries lying at the medial and lateral aspects of the pICA. Branches of the APA were observed in 13/20 sides (65%). Two branches were found in 9/13 sides and 3 branches in 4/13, respectively. The APA was only identifiable in 1/10 (10%) of pre-styloid tumors, a patient with basal cell adenoma. In contrast, the APA was encountered surrounding the pICA in 8/10 (80%) of patients with retro-styloid tumors, all of which were schwannomas. No inadvertent injury of the APA or the pICA occurred in this cohort. Conclusions: With identification of the ascending pharyngeal artery on preoperative magnetic resonance imaging, it may serve as an additional landmark during the endoscopic extirpation of tumors arising in the PPS.

Management of Parapharyngeal Space Tumors: Clinical Experience with a Large Sample and Review of the Literature

Parapharyngeal space (PPS) tumors are rare, and they account for 0.5-1.5% of all head and neck tumors. This study summarized the findings of large-sample clinical studies of PPS tumors and reported the clinical work-up and management of 177 cases of PPS tumors at our center. This retrospective study included patients treated for PPS tumors between 2005 and 2020 at our center. The basic characteristics, symptoms, surgical approach, complications, and recurrence rates were analyzed. A total of 99 male and 78 female patients, with a mean age of 48.3 ± 15.1 years, were enrolled in this study. The most common symptoms were external or intraoral masses (114 patients, 64%). Surgical management leveraging, a cervical approach, was used for 131 cases (74%). The tumors were benign for 92% (160 cases), with pleomorphic adenoma being the most common (88 cases, 50%). Surgical complications were reported for 31 cases (18%); facial and vocal cord paralyses were the most common. Three cases of recurrence were observed during the follow-up. PPS tumors are rare and present with atypical clinical manifestations. The current study, which involved cases in a large single center, demonstrates the importance of surgical interventions for PPS tumors. The use of endoscopic techniques has further expanded the scope of traditional surgical approaches and demonstrated its advantages in selected cases.

Endoscopic transoral approach to the lateral poststyloid space

The lateral poststyloid space (LPSS) located at the posterolateral aspect of the styloid process. This study aims to explore the anatomical relationships in LPSS via a transoral corridor, providing reference for addressing lesions extending to this region. An endoscopic transoral approach for exposure of the LPSS was performed on 6 cadaveric specimens (12 sides). Related landmarks were explored, and transoral extirpation of tumors extended into LPSS was employed in 12 patients. The deep lobe of the parotid gland, extratemporal facial nerve, and the accompanying artery in the LPSS were sufficiently exposed via the transoral corridor in all 12 cadaveric sides. The transoral corridor provided adequate exposure for tumors extending to the LPSS, and en bloc resection was achieved in these 12 patients. No facial nerve or vascular injury occurred, and no recurrence observed in this cohort with an average follow-up of 26 months. An endoscopic transoral approach provides a direct access to the LPSS. Appreciation of the anatomical relationships within the LPSS is valuable for employing a transoral extirpation of tumors extending to this specific region.

Endoscopic trans-lateral oropharyngeal wall approach to the petrous apex and the petroclival region

BACKGROUND

A trans-lateral oropharyngeal wall approach (TLOWA) to the petrous apex has not been previously defined. This study aims to assess the feasibility of a TLOWA for surgical access to the petrous apex and the petroclival region.

METHODS

An endoscopic TLOWA for exposure of the petrous apex and petroclival region was performed on five cadaveric specimens (10 sides). Associated anatomical landmarks were defined, and the strategies for maximal exposure of the internal carotid artery (ICA) were explored.

RESULTS

Via a TLOWA, the parapharyngeal ICA was widely exposed in all 10 sides. Following transection of the Eustachian tube, the inferior petrous apex and petroclival region could be sufficiently exposed. After drilling the anteroinferior bony canal, the horizontal petrous ICA, foramen lacerum, and the paraclival ICA could be adequately revealed.

CONCLUSION

The TLOWA may provide an alternative corridor for access to the petrous apex and the petroclival region. The parapharyngeal, petrous, lower paraclival ICAs, and the foramen lacerum could be adequately exposed via the TLOWA.

Transoral Approach to the Jugular Foramen Region with Preservation of the Eustachian Tube

OBJECTIVES/HYPOTHESIS

Transnasal exposure of the jugular foramen region (JFR) often requires transection of the Eustachian tube (ET). This study aims to propose a transoral corridor for access to the JFR with preservation of the ET.

STUDY DESIGN

Cadaveric dissection and case illustration.

METHODS

An endoscopic transoral approach for exposure of the JFR was performed on 5 cadaveric specimens (10 sides). Six patients who underwent a transoral resection of schwannoma within the JFR were retrospectively analyzed.

RESULTS

Direct exposure of the JFR with a 0° scope via a transoral approach was feasible, and the internal carotid artery and lower cranial nerves could be adequately exposed, and preservation of the ET was achieved in all 10 sides of the cadaveric specimens. For six patients with JFR tumors, the transoral approach provided adequate access to achieve a gross total resection with ET preservation. Intraoperative cerebral spinal fluid (CSF) leak was encountered in one patient, and a multilayer reconstruction was employed for reconstruction. No operative field or intracranial infection, persistent CSF leak, or emergent airway issues occurred. No recurrence occurred in this cohort with an average follow-up of 12 months.

CONCLUSIONS

The transoral approach provided a reliable corridor for access into the JFR with preservation of the ET. For select lesions with expansion into the posterior cranial fossa, a transoral corridor may serve as an alternative for tumor extirpation.

LEVEL OF EVIDENCE

4 Laryngoscope, 2022.