Experience and anatomical study of modified lengthening temporalis myoplasty for established facial paralysis

Summary Lengthening temporalis myoplasty, reported by Daniel Labbe in 1997, is a unique and definite facial reanimation procedure that involves moving the whole temporal muscle anteroinferiorly and inserting its tendon directly into the nasolabial fold. In the present article, we report our experience in the use of his modified method of the procedure, which preserves the zygomatic arch by transecting the coronoid process through the nasolabial fold incision. We also describe our cadaveric study that aimed to elucidate a secure approach for coronoid process transection. We performed this procedure in five patients with permanent facial paralysis. To improve facial symmetry, we also performed several additional static reconstructions such as T-shaped double-sleeve fascia grafts for lower lip deformities. We were successful in achieving considerable static improvement at rest, immediately after the surgery, and the recovery of facial movement was apparent approximately 3 months after the surgery. With regard to the cadaveric study, we noted that the entry to the buccal fat region, which is also the pathway of the temporal fascia, was a narrow space, and a short transection of the medial upper edge of the masseter fascia would make it easy to locate the coronoid process. Therefore, for a safe and secure access to the coronoid process from the nasolabial fold, we believe that we should first expose the cranial side and continue to dissect along the side and lower edge of the maxilla to locate the medial upper edge of the masseter fascia. By transecting along its edge, we could easily access the coronoid process, located immediately behind it, and widen the pathway of the temporal fascia. This modified method is less invasive and simpler compared to the original procedure, and understanding the detailed anatomy for dissection would help surgeons perform this procedure more confidently.