INTRODUCTION

This study was conducted to describe clinical manifestations of facial nerve single branches injuries due to facial plastic surgeries; to evaluate the method of therapeutic correction of impaired motor functions of mimic muscles using botulinum toxin type A Relatox in the acute and long-term periods of facial nerve damage after facial plastic surgeries.

MATERIAL AND METHODS

Thirty two patients (all patients were female) with acute paresis of mimic muscles due to facial nerve single branches injuries because of facial surgery for aesthetic purposes were examined. Anamnestic analysis was conducted to determine premorbid disorders, method of surgical treatment, and the postoperative course. Clinical evaluation of the mimic muscles condition with the use of mimic tests was carried out. All patients were injected with botulinum toxin type A Relatox into muscles of the contralateral (healthy) half of the face, which is in constant hypertonus. This is one of the causes of mimic asymmetry (static and dynamic) and prevents restoration of the activity of paretic muscles. Treatment efficacy was assessed using the House-Brackmann scale.

RESULTS

Fourteen (43.7%) patients had clinical signs of unilateral injury of temporal branch of the facial nerve in the form of peripheral paresis of the frontal, glabellar muscles and orbicularis oculi muscle. These patients have undergone the following surgeries: fronto-temporal lifting (n=8) and face lift with SMAS-facelift (n=6). In 10 (31.2%) patients there were clinical signs of unilateral injury of the zygomatic and cheek branches of the facial nerve in the form of smile asymmetry. The changes developed after endoscopic cheek-lifting with additional intraoral access for fixation of facial soft tissues (n=7) and circular skin facelift (n=3). Eight (25%) patients were diagnosed with clinical signs of unilateral injury of the marginal branch of the facial nerve in the form of peripheral paresis of the lower lip, which developed after facelift with platysmoplasty. Before starting botulinum therapy, the patients were divided into two groups: the 1st group consisted of 15 (47%) patients who were in the acute period of the disease (from 5 to 30 days after the surgery); the 2nd group (n=17; 53%) included patients in the long-term period after the surgery (from 1 month to 4 years). Before the start of botulinum therapy, the patients had an average dysfunction according to the House-Brackmann scale: 2.57±0.85 points in the 1st group and 2.77±0.79 points in the 2nd group. In the 1st group of patients in a month after the beginning of treatment there was a significant improvement, while in the 2nd group the improvement of facial nerve function came only after 9 months, after three times course of repeated injections (at the beginning of therapy, then after 3 months and 6 months) (p<0.05). The majority (n=9) of patients from the 1st group had enough to use botulinum toxin type A Relatox once for full recovery of the affected muscles. One year after injections, patients in the 1st group showed a persistent clinical effect, without the development of complications (residual paresis, contractures and muscle synkinesis). Whereas in the 2nd group there were signs of residual paresis (n=5) and synkinesis (n=5).

CONCLUSION

The most common cause of traumatic injury of the distal facial nerve branches after facial plastic surgeries is endoscopic lifting techniques. The local injections of botulinum toxin type A Relatox in the muscles of the contralateral (unaffected) side for correction of iatrogenic mimic asymmetry developed as a consequence after facial plastic surgery is effective both in the acute and long-term periods. However, monotherapy with the use of botulinum toxin type A in the acute period demonstrates the fastest, most effective and stable result. It is necessary to include botulinum therapy in the comprehensive rehabilitation program for this category of patients.

Keywords. mimic asymmetry, hypertonus of contralateral mimic muscles, complications of plastic surgery, botulinum toxin type A