The modified scar approach for young patients undergoing lengthening temporalis myoplasty

The temporalis muscle and its relationship to the accessory attachments and the main pedicle-a cadaveric study

Lengthening temporalis myoplasty, described by Daniel Labbe in 1997, is a facial reanimation procedure for the treatment of facial nerve palsy. It involves the mobilization of temporalis muscle antero-inferiorly, and the insertion of its tendon at the nasolabial fold-oral commissure region. Knowledge of the temporalis muscle is crucial in performing this procedure; however, previous anatomical studies are limited. This study on cadavers, aimed to describe the anatomical location of the temporalis muscle insertion in relation to the adjacent structures, and its main pedicle to aid surgeons in performing this procedure. Twenty-four temporalis muscles were dissected in 12 fresh frozen cadavers. The anatomical location of the temporalis muscle insertion, accessory attachments, the emergence of the posterior deep temporal artery, and the distance of sliding movements from the coronoid process to the nasolabial fold were recorded. In addition to its origin from the temporalis fossa and its insertion at the coronoid process, the temporalis muscle was found to have multiple accessory attachments to adjacent structures. These findings explain the challenges in performing the sliding action without releasing the accessory attachments to the masseter and pterygoid muscles. The deep posterior temporal artery is located inferoposteriorly in relation to the muscle. Therefore, the muscle elevation maneuver performed without direct vision can be done with minimal risk to the muscle pedicle. The knowledge of temporalis muscle insertion, its accessory attachments, and its main pedicle will facilitate surgeons in performing the lengthening temporalis myoplasty more confidently.

Modified Lengthening Temporalis Myoplasty Involving an Extended Lazy-S Incision to Avoid Facial Scar Formation

BACKGROUND

Lengthening temporalis myoplasty is a faster and less invasive alternative to free muscle transfer for smile reconstruction. However, it requires a nasolabial fold incision, which leaves a midfacial scar. Based on esthetic considerations, a modified approach, involving an extended lazy-S (parotidectomy) incision instead of a nasolabial fold incision, was developed.

METHODS

A cadaveric study involving 10 hemifaces was conducted. From February 2013 to March 2016, the modified lengthening temporalis myoplasty procedure was employed in 10 patients. The results were graded from 1 (poor) to 5 (excellent) according to the Terzis grading system. The excursion of the oral commissure was also measured.

RESULTS

The extended lazy-S incision provides easy and safe access to the coronoid process and good visibility. The patients' mean age was 56.5 years, and the mean duration of the postoperative follow-up period was 22.2 months. The patients' underlying conditions included acoustic neuroma (n = 2), Bell palsy (n = 3), congenital conditions (n = 2), brain infarction (n = 1), Ramsay Hunt syndrome (n = 1), and malignant parotid lymphoma (n = 1). One patient suffered a surgical site infection, which was successfully treated with irrigation. All the patients achieved improvements in smile symmetry: 2, 5, and 3 patients obtained excellent, good, and moderate results, respectively. The excursion of the oral commissure ranged from 5 to 10 mm.

CONCLUSION

The modified lengthening temporalis myoplasty procedure provides satisfactory functional outcomes without causing significant complications. It does not leave a facial scar and is a preferable option, especially for young and female patients, and patients who have undergone ablative surgery involving the parotid region.