Decreasing the width or excessive convexity of the side of the head is done by removal of the posterior temporalis muscle. Despite being only about 1/3 of the total volume of the entire temporalis muscle, it has enough thickness to it that its removal makes for a very visible change in the profile of the side of the head above the ears. Its loss results in no functional limitations for mouth opening and closing undoubtedly due to its relatively low contribution to overall temporalis muscle size.
When the desire for temporal reduction is more anterior, the surgical considerations change. Because of a more exposed incisional placement for access and to avoid contour deformities which may also be associated with some functional issues, cutting out portions of the anterior temporalis muscle is not an option.
A more viable approach to anterior temporalis muscle reduction is a direct thermal treatment. Using electrocautery the outer surface of the desired area of anterior temporal fullness can be treated. This can be done through a small incision using a long curved retractor to access muscle areas some distance from the incision. How much to cauterize the muscle is an intraoperative judgment. But the production of a char on its outer surface is desired.
The key question is where to place the incision. While the incision location must allow the desired area of treatment to be reached, it must also be as hidden as possible. Based on hairstyle, one option is to place it in a superior location. While a 2cm long incision is small it is advisable to be thoughtful of its placement.
Unlike posterior temporalis muscle reduction, electrocautery treatment of the anterior muscle takes longer to see the resultant narrowing. Relying on muscle atrophy from the thermal injury takes two to three months to see its full effect.
Dr. Barry Eppley