An anatomic mathematical measurement to find an adequate recipient M4 branch for superficial temporal artery to middle cerebral artery bypass surgery.

ABSTRACT

OBJECTIVE: With the recent interest in superficial temporal artery-middle cerebral artery (MCA) bypass for hemodynamic related ischemia, we performed an anatomic study to find the best possible craniotomy site that will allow finding a suitable recipient cortical artery without compromising the use of the best branch and/or segment of the donor's superficial temporal artery branches. METHODS: Anatomic dissection and measurements were performed in 15 injected cadaveric heads to verify the location of an adequate temporal recipient cortical branch of the MCA. The location of the branch was then correlated with surface anatomic landmarks. Mathematical measurements were then derived. RESULTS: A perpendicular line measuring 5 cm in length is drawn starting from a point two-thirds the distance from the lateral canthus to the tragus, and ending at the center of a circle measuring 3 cm in diameter, which is equivalent to the craniotomy size and site. This craniotomy will expose the posterior aspect of the sylvian fissure and exposes no less than two M4 temporal MCA branches. The diameter of at least one branch is larger than 1 mm in 93% of the specimens. These findings were later successfully applied to several bypass operations. CONCLUSION: This study provides an anatomic and patient-independent mathematical measurement as a way to predictably find an adequate recipient temporal M4 branch for superficial temporal artery-MCA bypass in the majority of patients.