Contralateral Botulinum Toxin Type A Injections for Facial Symmetry in Patients with Complete Facial Nerve Paralysis

Facial nerve paralysis may cause marked facial asymmetry and functional and social difficulties. Contralateral injection of botulinum toxin type A (BTX-A) is used to weaken the muscles on the unaffected side and improve facial balance. The objective of this study was to assess changes in facial asymmetry and facial disability after contralateral BTX-A injections in patients with facial nerve paralysis. This prospective study was conducted from November 2017 to December 2018 and included 15 patients with unilateral, complete facial paralysis (House–Brackmann grade VI). The patients were 11–65 years old; nine were male and six were female. BTX-A was injected into selected facial muscles on the unaffected side. Facial asymmetry was assessed using a visual analogue scale (VAS), and functional and social disability were assessed using the Facial Disability Index (FDI). Follow-up assessments were performed after one week and at two, four, and six months. The mean patient-rated VAS decreased from 8.5 ± 1.18 before injection to 2.93 ± 0.88 after one week and 3.66 ± 1.54 after four months (P = 0.001 for both comparisons). The surgeon-rated VAS decreased from 8.5 ± 1.18 to 2.73 ± 1.09 and 3.46 ± 1.24, respectively (P = 0.001). The mean functional FDI score increased from 33.66 ± 5.49 before injection to 71.46 ± 7.75 at two months and 61.73 ± 10.31 at four months. The social FDI score increased from 28.33 ± 4.08 to 63.33 ± 7.94 and 55.33 ± 10.08, respectively (P = 0.001 for the reported comparisons). Mild injection pain was reported in all patients; drooling and difficulty speaking were also recorded. In this group of patients with complete facial paralysis, contralateral BTX-A injections were associated with improved facial symmetry scores and higher functional and social FDI scores during follow-up. The observed improvement was still present at four months, although the scores had moved away from their best post-treatment values.