Minimally Invasive Exposure of the Infratemporal Maxillary Artery for Extracranial–Intracranial Bypass

Background: Various techniques have emerged to localize and harvest the maxillary artery (MA) for its use as a donor in cerebrovascular bypass surgery. All of these techniques require middle fossa dissection, brain retraction, and drilling of the skull base. Also they have a potential risk of venous plexus bleeding, possible injury to branches of trigeminal nerve, muscular transection, or risk of temporomandibular junction disorders.

Objective: To present a novel isolation technique of the MA at the infratemporal fossa for extracranial-intracranial bypass purposes without zygomatic osteotomy, and without middle fossa drilling.

Methods: Eight adult cadaveric heads were dissected (total of ten specimens). A conventional pterional approach was performed with a subfascial dissection of the temporalis muscle. MA was identified following the sphenozygomatic suture (SZS) to the anterolateral edge of the inferior orbital fissure (IOF), locating the infraorbital artery (IOA), tracking it back to its origin; once the main trunk of the MA was identified, it was dissected distally just prior to its entrance through the pterygomaxillary fissure (PMF). Anatomical topography was assessed using surrounding bony landmarks and 3D Cartesian coordinates were obtained to define the surgical area exposed. The total length and visible branches of MA were recorded.

Results: We successfully exposed the MA in all specimens. The average distance between the three-suture junction and the MA was 40.71 ± 7.48 mm and, on average, the anterolateral edge of the IOF was found to be 11.46 ± 4.19 mm from the MA. The average length of the MA exposed was 23.31 ± 8.30 mm and the average surgical area was 2.84 cm² (s.d. = 1.05). Additionally, this approach allowed six branches of the MA to be exposed. While the posterior superior alveolar and anterior deep temporal branches were exposed in all specimens (10/10), the infraorbital branch was found 90% (9/10) of the time. The anterior deep temporal and the pterygoid branches were exposed 80% (8/10) of the time and the masseteric branch was only identified in 4 out of 10 specimens.

Conclusion: Our technique provides efficient and safe landmarks to identify the distal pterygoid and proximal pterygopalatine segments of MA for EC-IC bypasses without the need of time-expending procedures such as drilling or osteotomies. Clear anatomical landmarks, such as the SZS, anterolateral edge of IOF, IOA, and the PMF could provide a trajectory to localize MA with minimal risk to surrounding structures.