Modified endoscopic endonasal approach with a minimally invasive transoral approach-an adjunct to infrapetrous approaches.

OBJECTIVES/HYPOTHESIS: To evaluate the potential of a minimally invasive transoral-transpalatal approach (MITA) to the retrocarotid petrous apex, as an adjunct to endoscopic endonasal approaches (EEAs).

STUDY

DESIGN

Cadaver study.

METHODS

Five cadaveric specimens were dissected raising an inverted U-shaped palatal mucoperiosteal flap, and drilling a rectangular palatotomy (between the greater palatine foramens, and just anterior to the palatine aponeurosis). This allowed a transpterygoid EEA with cross-court access (contralateral line of sight), followed by an extradural clivectomy that exposed the petroclival junction bilaterally. Surgical targets were marked on the posterior and medial surface of the petrous internal carotid artery (ICA), at its anterior genu, midhorizontal portion, and posterior genu. For each target and approach, the surgical freedom and angles of approach (in the horizontal and vertical planes) were calculated and statistically compared.

RESULTS

Compared to EEA, the MITA resulted in greater surgical freedom for all targets, with the highest values at the anterior genu (1,661.37 mm2 vs. 312.76 mm2 , P <.001), and maintaining superiority in this regard all the way to the posterior genu (847.84 mm3 vs. 138.91 mm3 , P < .005). MITA also offered greater angles of approach for all targets.

CONCLUSIONS

This study suggests that the MITA may be indicated to supplement the exposure provided by a transpterygoid EEA. This technique, associated with low potential morbidity, offers an alternative to internal carotid lateralization while managing extradural lesions that are adjacent to the petrous ICA.

LEVEL OF EVIDENCE: NA Laryngoscope, 129:339-343, 2019.