Injectate distribution patterns in posterior infrazygomatic and transoral approaches to the pterygopalatine fossa

Injectate distribution patterns in the pterygopalatine fossa may differ based on the drug administration approach used. This study primarily aimed to assess and compare injectate distribution following the posterior infrazygomatic and transoral approaches. The secondary aim was to evaluate the safety of both approaches.

Injectate distribution patterns were evaluated in 13 cadaveric head specimens. The vessels were perfused with a gelatin-based solution containing an iodinated contrast agent. The ultrasound-guided posterior infrazygomatic approach and transoral approach were performed on contralateral sides, and needle placement was confirmed using computed tomography (CT). A methylene blue and iodinated contrast agent solution was administered following successful needle placement. Injectate distribution and injuries were assessed via CT and anatomical dissection.

With the posterior infrazygomatic approach, methylene blue consistently stained the maxillary artery and nerve, sphenopalatine ganglion, and lateral pterygoid muscle, whereas with the transoral approach, it most frequently surrounded the maxillary artery and structures within the greater palatine canal. The iodinated contrast agent was distributed predominantly along the needle trajectories for both approaches. Injuries to the maxillary artery and facial nerve were documented following the posterior infrazygomatic approach, whereas injury to the lateral pterygoid plate was observed following the transoral approach.

With the posterior infrazygomatic approach, contrast agent encompassed the entire pterygopalatine fossa, whereas the transoral approach yielded a more localized distribution, primarily within the inferior portion and greater palatine canal. These differences in distribution patterns should guide the selection of the most appropriate approach based on the specific clinical indication.