Mini-invasive temporalis muscle tendon transfer and lengthening temporalis myoplasty for facial reanimation - a retrospective outcome analysis.

Background: Long-standing facial nerve paralysis leads to profound functional, aesthetic, social, and psychological impairments, significantly reducing patients' quality of life (QOL). Lengthening temporalis myoplasty and mini-invasive temporalis muscle tendon transfer are considered standard treatment options for dynamic facial reanimation in patients with flaccid facial paralysis, particularly in patients for whom more extensive free functional muscle transfers may not be suitable. The aim of this study was to retrospectively evaluate these two temporalis muscle-based reanimation techniques in an institutional patient cohort, as there is a lack of comparative studies addressing their outcomes.

Methods: Between 2015 and 2021, 23 patients with long-standing (>18 months) flaccid facial palsy underwent dynamic reanimation surgery using either lengthening temporalis myoplasty (N = 8) or mini-invasive temporalis muscle tendon transfer (N = 15). Patient selection favoured local transfers in older or comorbid patients or when cross--facial nerve grafts were contraindicated. Many patients also underwent adjunctive static procedures, such as nasal ala suspension (N = 7) and/or lagophthalmos correction (N = 17). Postoperative physiotherapy employed the Mirror-effect protocol to improve muscle control and smiling ability. Outcomes were assessed pre-and postoperatively using clinician-reported House-Brackmann (HB) and eFACE scores, as well as the patient-reported Facial Palsy Disability Questionnaire (FPDQ). Statistical analysis was conducted using the Wilcoxon paired test and Fisher's exact test (significance P < 0.05).

Results: The mean patient age was 54.4 years (SD = 16.1), with 15 females and 8 males. The average follow-up to stable surgical results was 10.6 months (SD = 7.8). For the mini-invasive temporalis muscle tendon transfer group (N = 15), mean improvements were observed as follows: 1.6 HB points (SD = 0.6), 34.1% eFACE static (SD = 14.1), 28.1% eFACE dynamic (SD = 19.0), and 34.2% FPDQ overall score (SD = 11.3), with total of 3 revisions performed. For the temporalis myoplasty group (N = 8), mean improvements were 1.6 HB points (SD = 0.7), 27.4% eFACE static (SD = 18.6), 33.3% eFACE dynamic (SD = 17.2), and 26.2% FPDQ overall (SD = 15.7), with one revision surgery performed. No statistically significant difference in outcome was found between the two surgical techniques.

Conclusions: Both surgical techniques for facial reanimation evaluated in this study - the lengthening temporalis myoplasty and the minimally invasive temporalis tendon transfer -demonstrated significant improvements in clinician-graded facial function and QOL outcomes. Although the minimally invasive technique required a less extensive surgical field in the temporal area, it required additional graft harvesting and was associated with a slightly increased risk of revision surgery. A limitation of this study is the relatively small number of patients in each group, highlighting the need for prospective and/or multicentric studies to validate and confirm our findings.