Correction of synkinesia using botulinum neuroprotein type A

Background. In patients with facial nerve (FN) injury, facial synkinesia and contractures on the affected side against the background of existing mimic muscle weakness can develop 4-6 months after neurosurgical interventions, and it can lead to significant social maladaptation and a decrease in the quality of life. Objective. Evaluation of the effectiveness of botulinum therapy in patients with synkinesia after neurosurgical interventions. Methods. The study included 150 patients with FN neuropathy after surgical treatment of tumors of the posterior cranial fossa and the cerebello-pontine angle, which were divided into two groups. Group I (main group) included 103 (68.7%) patients who had been prescribed botulinum toxin type A (BTA) - Incobotulinumtoxin A starting from the first days after FN injury. Synkinesia correction was carried out according to the following method: BTA was administered in small doses (0,5-1.5 ME per injection point) with symmetrical injection on the unaffected side at 1.5-2 fold higher dosese. Group II (control group) included 47 (31.3%) patients; they received physical therapy courses with special exercises and acupressure of painful muscular bands. The Sunnybrook Facial Grading Scale (SFGS) was used to assess facial symmetry and synkinesia. The quality of life during therapy was evaluated according to the FDI (Facial Disability Index) scale. The total duration of patient participation in the study was 2 years (control points - 6, 12 and 24 months). Results. Six months after the FN injury, synkinesia was detected in 48 (46.6%) and 30 (63.8%) patients, 1 year later - in 28 (27.2%) and 32 (68.1%; p<0.001), and 2 years later - in 14 (13.6%) and 40 (85.1%; p<0.001) patients of groups I and II, respectively. 6, 12, and 24 months after FN injury, the general condition of the facial muscles according to SFGS scale was 2.0, 2.3, and 1.68 fold better in patients of group I compared to the patients of group II (p<0,01). Against the background of the treatment of synkinesia in patients of group I, the severity of clinical symptoms significantly decreased, which was expressed in the form of a decrease in the frequency of involuntary contractions, decreased Chvostek’s sign on the unaffected side, low rate of blinking, as well as a decrease in masseteric hypertrophy on the unaffected side, less dry eye symptom and Bogorad’ symptom at 6, 12 and 24 months of the study compared to the patients of group II. In patients receiving botulinum therapy, the quality of life was also significantly higher during the whole period of the study. Conclusion. In case of synkinesia in patients after neurosurgical interventions for tumors of the posterior cranial fossa and the cere-bello-pontine angle, botulinum therapy is indicated both on injured and unaffected sides, while the dose of the drug on the injured side should be 1/2 to 1/3 of the that on the unaffected side.

synkinesia, facial nerve, botulinum toxin type A, neurosurgery