Double innervation (facial/masseter) sur le lambeau gracile dans les réanimations du tiers moyen de la face lors de la prise en charge des paralysies faciales : nouveau concept

Anatomic Considerations of Perinasal Musculature for Improved Dental Show During Smile in Facial Synkinesis

Introduction:

There is an anatomic explanation for upper lip and midfacial tethering resulting in lack of motion in facial synkinesis.

Objective:

To measure the effect of perinasal chemodenervation on dental show in the synkinetic population and clarify the anatomic relationship of perinasal musculature.

Methods:

Literature search was performed on anatomy of the perinasal modiolus, and anatomic evaluation was performed through human anatomic specimen dissection. Photographic outcomes were observed in synkinetic patients receiving chemodenervation to smile antagonists with and without perinasal muscle injections and assessed through naive observer survey. Retrospective outcomes for all patients receiving perinasal chemodenervation was collected utilizing Facial Clinimetric Evaluation Scale, Sunnybrook Facial Grading System (FGS), Facial Disability Index (FDI), and the Synkinesis Assessment Questionnaire.

Results:

Anatomic dissections demonstrated muscular confluence spanning the nasal sidewall and upper lip tethering the soft tissue to bone. Thirty-four of 53 chemodenervation patients received perinasal Botox experiencing improvement in synkinetic symptoms of the upper lip, nose, and improved dental show as noted on paired t-test for FGS (p = 0.00096), and FDI social p = 0.015) also supported by naive observer surveys (p = 0.03).

Conclusions:

Human anatomic specimen dissections support a perinasal confluence of musculature with bony attachments that can be successfully treated with chemodenervation in facial synkinesis patients.

Advances in facial nerve management in the head and neck cancer patient

PURPOSE OF REVIEW

The purpose of this review is to summarize best practices in facial nerve management for patients with head and neck cancer. In addition, we provide a review of recent literature on novel innovations and techniques in facial reanimation surgery.

RECENT FINDINGS

Although recommended when tumor ablation surgery requires facial nerve sacrifice, facial reanimation procedures are not always performed. Concurrent dynamic facial reanimation with masseteric nerve transfers and cable graft repair can preserve native facial muscle function. Static suspension can provide facial support and immediate resting symmetry for patients. Eyelid weight and eye care should not be delayed, particularly in patients with trigeminal sensory deficits. Choice of neural source to innervate a gracilis-free muscle transfer for smile reanimation remains controversial; however, new techniques, such as dual innervation and multivector muscle transfer, may improve aesthetic and functional outcomes.

SUMMARY

Management of the facial nerve in the setting of head and neck cancer presents unique challenges. When possible, simultaneous oncologic resection and facial reanimation is ideal given the open surgical field, newly dissected and electrically stimulatable facial nerve branches, as well as minimizing postoperative healing time to prevent postsurgical treatment delays. A coordinated approach to facial nerve management with a multidisciplinary surgical team may help provide optimal, comprehensive care.

Spontaneity Assessment in Dually Innervated Gracilis Smile Reanimation Surgery

Importance

Surgeons have sought to optimize outcomes of smile reanimation surgery by combining inputs from nerve-to-masseter and cross-face nerve grafts. An objective assessment tool could help surgeons evaluate outcomes to determine the optimal neural sources for smile reanimation.

Objective

To evaluate the use of a novel video time-stamping method and standard outcome measurement tools to assess outcomes of facial reanimation surgery using various innervation strategies.

Design, Setting, and Participants

Cohort study assessing the outcomes of dually innervated gracilis free muscle transfers vs single-source innervated gracilis transfer performed at a tertiary care facial nerve center between 2007 and 2017 using a novel, video time-stamping spontaneity assessment method. The statistical analyses were performed in 2018.

Interventions

Dually innervated gracilis free muscle transfers or single-source innervated gracilis transfer.

Main Outcomes and Measures

Spontaneous smiling was assessed by clinicians and quantified using blinded time-stamped video recordings of smiling elicited while viewing humorous video clips.

Results

This retrospective cohort study included 25 patients (12 men and 13 women; median [range] age, 38.4 [29.3-46.0] years) treated with dually innervated gracilis free functional muscle graft for unilateral facial palsy between 2007 and 2017. Smile spontaneity assessment was performed in 17 patients and was compared with assessment performed in 24 patients treated with single-source innervated gracilis transfer (ie, nerve-to-masseter-driven or cross-face nerve graft-driven gracilis [n = 13]) (demographic data not available for NTM and CFNG cohorts). The use of time-stamped video assessment revealed that spontaneous synchronous oral commissure movement in a median percentage of smiles was 33% in patients with dually innervated gracilis (interquartile range [IQR], 0%-71%), 20% of smiles in patients with nerve-to-masseter-driven gracilis (IQR, 0%-50%), and 75% of smiles in patients with cross-face nerve graft-driven gracilis (IQR, 0%-100%). Clinicians graded smile spontaneity in dually innervated cases as absent in 40% (n = 6 of 15), trace in 33% (n = 5 of 15) and present in 27% (n = 4 of 15). No association was demonstrated between clinician-reported spontaneity and objectively measured synchronicity.

Conclusions and Relevance

Dually innervated gracilis free muscle transfers may improve smile spontaneity compared with masseteric nerve-driven transfers but not to the level of cross-face nerve graft-driven gracilis transfers. Quantifying spontaneity is notoriously difficult, and most authors rely on clinical assessment. Our results suggest that clinicians may rate presence of spontaneity higher than objective measures, highlighting the importance of standardized assessment techniques.

Level of Evidence

4.

Facial Paralysis Discussion and Debate

This article examines 6 questions about facial paralysis answered by 3 experts in their field of facial plastic surgery. The topics covered include routine assessment, neuromuscular training, nonsurgical management, and the future of this field. All the authors answered these questions in a "How I do it" manner to provide the reader with a true understanding of their thoughts and techniques. This article provides a practical resource to all physicians and practitioners treating patients with facial paralysis on some of the most common questions and issues.

Outcome Tracking in Facial Palsy

Outcome tracking in facial palsy is multimodal, consisting of patient-reported outcome measures, clinician-graded scoring systems, objective assessment tools, and novel tools for layperson and spontaneity assessment. Patient-reported outcome measures are critical to understanding burden of disease in facial palsy and effects of interventions from the patient perspective. Clinician-graded scoring systems are inherently subjective and no 1 single system satisfies all needs. Objective assessment tools quantify facial movements but can be laborious. Recent advances in facial recognition technology have enabled automated facial measurements. Novel assessment tools analyze attributes such as spontaneous smile, emotional expressivity, disfigurement, and attractiveness as determined by laypersons.

Mixed facial reanimation technique to treat paralysis in medium-term cases

Recent facial paralyses, in which fibrillations of the mimetic muscles are still detectable by electromyography (EMG), allow facial reanimation based on giving new neural stimuli to musculature. However, if more time has elapsed, mimetic muscles can undergo irreversible atrophy, and providing a new neural stimulus is simply not effective. In these cases function is provided by transferring free flaps into the face or transposing masticatory muscles to reinstitute major movements, such as eyelid closure and smiling. In a small number of cases, patients affected by paralysis are referred late - more than 18 months after onset. In these cases, reinnervating the musculature carries a high risk of failure because some or all of the mimetic muscles may atrophy irreversibly while axonal ingrowth is taking place. A mixed reanimation technique to address this involves a neurorrhaphy between the masseteric nerve and a facial nerve branch for the orbicularis oculi, to ensure a stronger innervation to that muscle, associated with the transposition of the temporalis muscle to the nasiolabial sulcus. This gives good symmetry in the rest of the midface, while smiling movement is achievable, but not guaranteed. This one-time facial reanimation is particularly indicated for those who refuse major free-flap surgery or when that may be risky, as in previously operated and irradiated fields. More extensive procedures based on utilizing a free flap to recover smiling, while adding a cross-face nerve graft to restore blinking, may be proposed for motivated patients. Between 2010 and 2015, five patients affected by complete unilateral facial palsy underwent this technique in the Maxillofacial Surgery Department, San Paolo Hospital (Milan, Italy). Symmetry of the middle-third of the face at rest and recovery of smiling was quite good. Complete voluntary eyelid closure was obtained in all cases. Combining temporalis flap rotation and a masseteric-to-orbicularis-oculi-facial-nerve branch neurorrhaphy seems to be a valid solution for those medium-term referred patients.

Facial nerve trauma: evaluation and considerations in management

The management of facial paralysis continues to evolve. Understanding the facial nerve anatomy and the different methods of evaluating the degree of facial nerve injury are crucial for successful management. When the facial nerve is transected, direct coaptation leads to the best outcome, followed by interpositional nerve grafting. In cases where motor end plates are still intact but a primary repair or graft is not feasible, a nerve transfer should be employed. When complete muscle atrophy has occurred, regional muscle transfer or free flap reconstruction is an option. When dynamic reanimation cannot be undertaken, static procedures offer some benefit. Adjunctive tools such as botulinum toxin injection and biofeedback can be helpful. Several new treatment modalities lie on the horizon which hold potential to alter the current treatment algorithm.

Reanimating the paralyzed face

Facial animation is an essential part of human communication and one of the main means of expressing emotions, indexing our physiologic state and providing nonverbal cues. The loss of this important human quality due to facial paralysis can be devastating and is often associated with depression, social isolation and poor quality of life. Interruption of the neuromuscular pathway from the facial motor cortex to the facial muscles is the common causative factor in facial paralysis resulting from various etiologies. Restoring tone, symmetry and movement to the paralyzed face requires timely nerve grafting intervention in cases of reversible paralysis and the transfer of functional muscle units in irreversible paralysis. We review recent advances in these techniques.