Anatomical Variations and Relationships of the Infratemporal Fossa: Foundation of a Novel Endonasal Approach to the Foramen Ovale

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.

Exploration of anatomical landmarks for performing an endoscopic transoral nasopharyngectomy

BACKGROUND

Performing a nasopharyngectomy via a transoral approach has been reported; however, defining landmarks to facilitate this approach has not been addressed. This study aims to explore anatomical landmarks to aid in performing a nasopharyngectomy via the transoral corridor.

METHODS

An endoscopic transoral nasopharyngectomy was performed on six cadaveric specimens (12 sides). Related anatomical landmarks were defined, and the strategy to preserve the parapharyngeal internal carotid artery (pICA) was explored.

RESULTS

An endoscopic transoral nasopharyngectomy was successfully achieved in all 12 sides. Utilizing the pterygoid hamulus as a landmark, the cartilaginous ET and attachments could be adequately exposed. Identification of the pICA is a prerequisite prior to Eustachian tube (ET) transection. The sphenoidal spine and the petrotympanic fissure could be sufficiently revealed in all 12 sides, which aided in transection of the cartilaginous ET without pICA injury. The ET and the prevertebral contents could be adequately removed via the transoral corridor.

CONCLUSION

The pterygoid hamulus, sphenoidal spine and petrotympanic fissure serve as reliable landmarks for performing a transoral nasopharyngectomy. Identification of the pICA is a prerequisite prior to transection of the ET to avoid pICA injury.

[Surgical approach of transnasal endoscopic resection of benign lesions in the paramedian lateral skull base]

Objective:To investigate the surgical approach of transnasal endoscopic resection of benign lesions in the paramedian lateral skull base. Methods:Retrospectively analyze 40 cases of the clinical data of patients with benign lesions of the skull base from August 2018 to February 2021 with transnasal endoscopic surgery, including 9 cases of cholesteatoma, 6 cases of hemangioma, 1 case of hemangiopericytoma, 6 cases of schwannoma, 15 cases of sphenoid sinus lateral crypt meningocele and cerebrospinal fluid leak, 3 cases of nasopharyngeal carcinoma bone inflammation after radiotherapy. All patients underwent transnasal endoscopic surgery, and different surgical approaches were selected according to the lesion location. Results:The total resection rate was 100% in 40 patients. One patient had cerebrospinal fluid rhinorrhea, which was cured after repair. During the follow-up period of 3-30 months, 39 patients had different degrees of numbness in the maxillary or mandibular region, and the numbness disappeared from 2 weeks to 6 months; one patient with schwannoma still had numbness on one side of the upper lip one year after surgery. Conclusion:Transnasal endoscopic resection of benign lesions in the paramedian skull base has a high surgical safety and cure rate. The surgical approach selection mainly focuses on the pterygoid process and extends to the periphery. The shortest and least damaging approach should be selected according to the lesion location, and the endoscopic approach should also be selected according to the surgeon's expertise.