Landmarks for the preservation of the middle temporal artery during mastoid surgery: Cadaveric dissection study.

IMPORTANCE: The middle temporal artery flap is a vascularized periosteal flap that is highly useful for otologic reconstruction including the middle cranial fossa, mastoidectomy defect, and external auditory canal. The course of the artery is close to the external auditory canal and is easily injured during preliminary exposure and elevation of flaps.

OBJECTIVES: To describe the course of the middle temporal artery in relation to the external auditory canal and the superficial temporal artery in order to enhance preservation and use in otologic reconstruction.

DESIGN: Dissection of preserved, injected cadaveric temporal bones.

SETTING: Anatomical laboratory.

PARTICIPANTS: Seven cadaveric temporal bones.

INTERVENTION: Temporal bones were dissected in a planar manner to identify the middle temporal artery along the squamous temporal bone to its origin. The superior border of the external auditory canal was divided, horizontally, into thirds to create three measurement points. Distances between the middle temporal artery and the bony portion of the external auditory canal were then determined.

MAIN OUTCOMES AND MEASURES: Horizontal diameter of the external auditory canal, distance from the superior-most border of the external auditory canal to the middle temporal artery, various patterns of the middle temporal artery.

RESULTS: The middle temporal artery branched from the superficial temporal artery in all specimens. Mean horizontal diameter of the external auditory canal was 9.97mm. Mean distances between the bony portion of the external auditory canal and middle temporal artery for the first, second, and third points along the horizontal diameter of the external auditory canal were 1.57, 2.96, and 4.02mm, respectively. In at least one specimen, the artery dipped into the external auditory canal.

CONCLUSIONS AND RELEVANCE: The middle temporal artery runs closest to the external auditory canal at the anterosuperior border. To preserve the middle temporal artery for use in reconstruction after otologic surgery, the surgeon should avoid dissection superior to the external auditory canal until the artery is positively identified.