Abstract
The internal maxillary artery (IMAX) is a promising arterial pedicle to function as
a donor vessel for extracranial-to-intracranial (EC-IC) bypass procedures. The access
to the IMAX through the anterior portion of the middle cranial fossa floor allows
a much shorter interposition graft to be used to create a bypass to the ipsilateral
middle cerebral artery and prevents a second incision in the neck. One of the challenges
of this technique, however, is the difficulty to find the IMAX through an intracranial
approach. The purpose of this cadaveric study is to establish a reliable method to
localize the IMAX through a middle fossa floor approach based on skull base bone landmarks.
In this study 5 latex-injected fixated cadaveric specimens were dissected bilaterally
(providing a total of 10 IMAX dissections) to determine the precise location of the
IMAX in the pterygopalatine fossa in relationship to bone landmarks of the middle
fossa floor as seen through an intracranial approach. Drilling of the middle fossa
floor was undertaken through both the originally described “anteromedial” approach,
and a new “anterolateral” approach. Measurements were taken correlating the position
of the IMAX to ipsilateral foramen rotundum, ipsilateral foramen ovale, posterior
wall of the maxillary sinus, and distal V2 branches. Median and standard deviation
were calculated for each dataset. The IMAX was found, within the pterygopalatine fossa,
by drilling the greater wing of the sphenoid bone on average 10 mm anteriorly and
5 mm laterally to foramen rotundum, at an average depth of 8 mm. The IMAX was also
found inferiorly to the maxillary nerve and laterally to the pterygoid head of the
lateral pterygoid muscle. A more laterally oriented approach, consisting of drilling
the greater wing of the sphenoid bone from a point perpendicular to foramen rotundum
posteriorly to the sphenotemporal suture anteriorly, allowed for a longer segment
of the IMAX to be easily identified and exposed facilitating its use as a donor vessel
in bypass procedures. This cadaveric study provides a reliable and reproducible set
of measurements to localize the IMAX within the pterygopalatine fossa through an intracranial
middle fossa approach. The ability to find the IMAX consistently is an important step
in exploring the possibility of using the IMAX as a routine donor vessel for EC-IC
bypass procedures.
Keywords
internal maxillary artery - extracranial-to-intracranial bypass - middle fossa approach
- anatomy
