Selective Neurectomy for Treatment of Post-Facial Paralysis Synkinesis: A Systematic Review

Abstract

Background: Synkinesis is commonly encountered after flaccid facial paralysis and can have a detrimental impact on a patient’s life. First line treatment of synkinesis is chemodenervation with Botulinum toxin (Botox) and neuromuscular retraining. Surgical options include selective myectomy, selective neurectomy (SN), cross-facial nerve grafting, nerve substitution, and free gracilis muscle transfer (FGMT). Data on surgical management of synkinesis using selective neurectomy is limited. Evidence Review PubMed, Embase, Cochrane CENTRAL, Cochrane Neuromuscular Register, Clinicaltrials.gov, and WHO ICTPR were searched using a comprehensive keyword strategy in accordance with PRISMA guidelines. All English-only texts published in the last 20 years were included. Two independent investigators reviewed 906 abstracts and 7 studies met inclusion criteria. Demographics, etiology of paralysis, time to surgery, and primary outcomes studied were collected. Findings A total of 250 patients were included across 7 studies. In 6 out of 7 studies, Botox was used prior to surgical intervention. Two studies showed significant reduction in Botox dosage postoperatively, while one study showed no difference. Other primary outcomes included the House-Brackman Score, palpebral fissure width, eFACE score, Facial Clinimetric Evaluation (FaCE) scale, and Synkinesis Assessment Questionnaire (SAQ). Three studies showed significant improvement in the eFACE score, two studies showed significant improvement in the FaCE scale, while one study showed improvement in quality of life measured by the SAQ. Conclusions Selective neurectomy can be considered as an adjunct to other management options including neuromuscular retraining, Botox, selective myectomy and reanimation procedures. While there is great heterogeneity of study design in the studies included, many cohorts showed improvement in facial symmetry, facial function, and quality of life. There remains a great gap in knowledge in this subject matter and a need for large well designed prospective studies comparing this technique to other management options.

Selective neurectomy for nonflaccid facial palsy

“…Not only were these techniques focused on reducing some of the discomfort related to tightness and synkinesis, but also improving smile and oral competence [15]. As techniques have continued to evolve over time, the surgical technique and patient management has become quite varied among surgeons [16 ▪▪ ].…”

“…Ideal candidacy includes those with “stable synkinesis over time, active zygomatic major/minor muscles, and intact distal branches of the facial nerve” [17 ▪ ]. There are two major patient populations that are historically represented in the literature: those with periocular synkinesis and those with a synkinetic smile [16 ▪▪ ]. While difficult to treat, highly selective neurectomy has been described as a treatment option for periocular synkinesis in cases that are refractory to chemodenervation [16 ▪▪ ,18,19].…”

“…There are two major patient populations that are historically represented in the literature: those with periocular synkinesis and those with a synkinetic smile [16 ▪▪ ]. While difficult to treat, highly selective neurectomy has been described as a treatment option for periocular synkinesis in cases that are refractory to chemodenervation [16 ▪▪ ,18,19]. The majority of other studies have focused on denervation of mid to lower facial branches that contribute to a synkinetic smile and oral incompetence [16 ▪▪ ,20,21,22 ▪▪ ,23,24].…”

“…While difficult to treat, highly selective neurectomy has been described as a treatment option for periocular synkinesis in cases that are refractory to chemodenervation [16 ▪▪ ,18,19]. The majority of other studies have focused on denervation of mid to lower facial branches that contribute to a synkinetic smile and oral incompetence [16 ▪▪ ,20,21,22 ▪▪ ,23,24]. MSN offers a logical correction of the aberrant neural regeneration contributing to synkinesis (e.g.…”

“…Numerous factors, including appropriate patient selection, contribute to the wide variation of selective neurectomy as a procedure. Additionally, methods of selecting nerve branches for denervation are quite variable [16 ▪▪ ]. Many techniques have been described, from intraoperative monitoring under general anesthesia to isolation of branches intraoperatively followed by identification of branches for sacrifice after the patient is awakened [17 ▪ ,19].…”