Anatomy of the sphenoidal spine and its implications in endoscopic endonasal surgery of the infratemporal fossa

The posterior or tubal sphenoidal plate extending into the tympanosquamous fissure - A novel finding

OBJECTIVE

The tympanic plate typically joins the articular tubercle in the medial glenoid wall. It is aimed to report a peculiar anatomic variant of the latter.

METHODS

The computed tomography scans of two adult male cases were documented for the anatomical details of the temporomandibular joint.

RESULTS

The absence of the tubal processes of the tympanic plates was found bilaterally. The medial glenoid walls were penetrated by posterior or tubal sphenoidal plates extending posteriorly from the sphenoidal spines, 6.6 mm/12.2 mm on the right/left sides in the first case, and 9.8/8.4 mm on the right/left sides in the second case. These plates formed the lateral tubal walls and modified the tubal sulci on the sphenopetrosal fissures into musculotubal pseudo-canals. On the sides of the tubal sphenoidal plates formed in the medial wall of the glenoid fossa additional fissures, an anterolateral sphenotemporal one and a postero-medial sphenotympanic one.

CONCLUSION

As far as the authors know, the tubal plate of the sphenoid bone was not observed previously to participate in the glenoid fossa's medial wall. It could be regarded as a rare anatomic variation.

Maximal exposure of the parapharyngeal internal carotid artery via transnasal and transoral corridors

BACKGROUND

The parapharyngeal internal carotid artery (pICA) could be surgically exposed through the transnasal and transoral corridors. However, their potential degree of exposure has not been established sufficiently. This study aims to elucidate the maximal exposure of the pICA via the transnasal and transoral corridors.

METHODS

An endonasal transpterygoid nasopharyngectomy for exposure of the pICA was performed on eight cadaveric specimens (16 sides), while a transoral approach for exposure of the pICA was performed on six additional specimens (12 sides). In addition, the CT angiography of 60 consecutive patients (120 sides) was analyzed to establish the potential maximal exposure of the pICA through each corridor.

RESULTS

The hard palate becomes a restricting factor for the inferior exposure of the pICA via the transnasal approach, whereas the entire pICA segment could be adequately displayed through the transoral corridor. The maximal exposed length of the pICA for a transnasal and transoral approach was 3.08 ± 0.30 cm and 6.56 ± 0.57 cm, respectively. This difference was statistically significant (p < 0.001).

CONCLUSION

An endonasal exposure of the pICA seems limited to its superior aspect, whereas the transoral corridor could provide adequate exposure of the entire length of pICA.

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.