Powering the Gracilis for Facial Reanimation: A Systematic Review and Meta-analysis of Outcomes Based on Donor Nerve

Outcomes of Free Flap Transfer in Facial Reanimation: A Review

Free functional muscle transfer is is an option for reanimating the face in chronic facial nerve paralysis. The optimal outcome in these patients is the ability to restore a spontaneous smile in response to emotion. We discuss the role of free functional muscle transfer in facial paralysis treatment, the choices of nerve used in reconstruction surgery, and the application of different types of muscle flaps in facial reanimation. In this paper, we review the relevant and up-to-date academic literature regarding the outcomes of free functional muscle flap transfer in facial paralysis patients.

Masseteric Nerve Ultrasound Identification for Dynamic Facial Reanimation Purposes

BACKGROUND

The masseteric nerve is one of the main options to neurotize free muscle flaps in irreversible long-term facial paralysis. Several preoperative skin-marking techniques for the masseteric nerve have been proposed to limit the surgical dissection area, shorten the surgical time, and enable a safer dissection. However, these have shown variability among them, and cannot visualize the nerve preoperatively. The authors designed an observational study to validate a high-frequency ultrasound (HFUS) nerve identification technique.

METHODS

A systematic HFUS examination was designed and performed to visualize the masseteric nerve in 64 hemifaces of healthy volunteers. One-third were randomly selected to undergo an additional HFUS-guided needle electrostimulation to validate the HFUS image.

RESULTS

The masseteric nerve was identified by HFUS in 96.9% of hemifaces (95% CI, 0.89 to >0.99) and showed almost perfect agreement with direct needle stimulation as calculated with Cohen kappa coefficient (0.95; 95% CI, 0.85 to 1.00). The masseteric nerve was found within the masseter muscle, in between the deeper muscle bellies, at 18.3 mm (SD ±2.2) from the skin. Only in 12.9% of cases (95% CI, 0.06 to 0.24) did its course become adjacent to the mandible periosteum. Other important features, such as disposition in relation to the parotid gland, or if the nerve was covered directly by a thick intramuscular aponeurosis, could be well observed by HFUS.

CONCLUSION

HFUS enables masseteric nerve identification and can provide the surgeon with specific information on anatomical relations for each examined individual before surgery.

Inverted gracilis muscle free flap with intraoral vascular anastomoses for facial reanimation in vessel depleted neck: A case report

The reinnervated gracilis muscle free flap represents a workhorse of facial reanimation. This procedure is carried out secondarily to parotid resections, due to advanced tumors that spread to the surrounding structures. Finding recipient vessels might be problematic if other reconstructive procedures are needed to address the defects. This paper describes a procedure to inset a reinnervated gracilis muscle free flap in a vessel depleted patient, through intraoral anastomoses to avoid venous interposition grafts. A 52-year-old man developed an advanced adenocarcinoma of the deep parotid lobe and underwent radical surgical excision including the mandibular ramus, condyle, and facial soft tissues (defect size: 8 cm × 4 cm). A secondary double-flap reconstruction restored the mandibular defect and inset a cross-face nerve graft. A third intervention finalized the facial reanimation with a 10 cm reinnervated gracilis muscle free flap. The gracilis flap inset was inverted resulting in the proximal flap (pedicle side) lying on the buccal aspect. This allowed vessel joining from the contralateral side via intraoral anastomoses. No complications occurred within and after the intervention. However, the adenocarcinoma relapsed before reinnervation of the gracilis. The patient also had distant brain and lung metastases and received best supportive care. The inverted gracilis muscle free flap may represent an option for attaining facial reanimation in vessel-depleted patients avoiding long interposition venous grafts.

Age-related outcomes of facial reanimation surgery using gracilis free functional muscle transfer innervated by the masseteric nerve: A retrospective cohort study

BACKGROUND

The free functional muscle gracilis transfer is an established approach in facial reanimation surgery; however, the significance of its neurotization and the patient's age is still inconclusive. Several donor nerves are available for facial reanimation using the free functional gracilis muscle transfer.

OBJECTIVE

This retrospective cohort study investigates whether the masseteric nerve is an equally reliable donor nerve in both older and younger patients.

METHODS

We included 46 patients (13-71 years, male and female) who underwent nerve-to-masseter (NTM)-driven free functional muscle transfer (FFMT) between January 2008 and December 2019. Patients were distributed into three cohorts according to their age at surgery. We assessed the facial symmetry before and after surgery using the pupillo-modiolar angle. Commissure height and excursion deviation were measured with the Emotrics software. Patient-reported outcome measurements were taken using the Facial Clinimetric Examination (FaCE) scale.

RESULTS

All patients had successful flap innervation, except for one patient in the middle-aged cohort (31-51 years). The postoperative facial symmetry at rest, smiling, and laughing was analyzed with the pupillo-modiolar angle and the Emotrics software and showed similar results between all cohorts. The FaCE scale showed similar scores for the middle-aged (31-51 years) cohort and the senior cohort (52-71 years). The social function score in the senior cohort was higher than in the middle-aged cohort, without statistical significance. One patient in the middle-aged (31-51 years) cohort and the senior cohort (52-71 years), respectively, underwent emergency revision due to impaired flap perfusion and could be salvaged.

CONCLUSIONS

NTM-driven FFMT for facial reanimation is a safe and reliable procedure across all age groups of patients.

Gracilis Muscle-Free Flap Objective Improvement of Oral Commissure Excursion in Facial Palsy Reanimation Surgery: Systematic Review and Meta-Analysis

Background: Facial palsy patients face significant challenges. Gracilis free flap transfer is a key procedure in facial reanimation. Objective: This study aims to analyze oral commissure excursion improvement after gracilis free flap transfer and the differences regarding donor nerve: cross-facial nerve graft (CFNG), hypoglossal or spinal accessory nerves, motor nerve to masseteric (MNTM), and most recently, double anastomosis using both the MNTM and CFNG. Methods: A systematic review and meta-analysis were conducted of studies reporting oral commissure excursion improvement after free gracilis muscle transfer. Pooled proportions were calculated using a random-effects model. Results: Eighteen studies, 453 patients, and 488 free gracilis flaps were included. The mean change in perioperative oral commissure excursion was 7.0 mm, for CFNG 7.2 mm, for MNTM 7.7, and for double anastomoses 5.5 mm. Conclusions: There is a significant improvement in oral commissure excursion after gracilis muscle-free flap. Unfortunately, we could not make definitive conclusions regarding the optimal choice of donor nerve.

Donor nerve selection in free gracilis muscle transfer for facial reanimation. A systematic review and meta-analysis of clinical outcomes

BACKGROUND

One of the critical factors in facial reanimation is selecting the donor nerve. The most favored neurotizers are the contralateral facial nerve with a cross-face nerve graft (CFNG) and motor nerve to the masseter (MNM). A relatively new dual innervation (DI) method has shown successful results. This study aimed to compare the clinical outcomes of different neurotization strategies for free gracilis muscle transfer (FGMT).

METHODS

The Scopus and WoS databases were queried with 21 keywords. Three-stage article selection was performed for the systematic review. Articles presenting quantitative data for commissure excursion and facial symmetry were included in meta-analysis, using random-effects model. ROBINS-I tool and Newcastle-Ottawa scale were used to assess bias and study quality.

RESULTS

One hundred forty-seven articles containing FGMT were systematically reviewed. Most studies indicated CFNG as the first choice. MNM was primarily indicated in bilateral palsy and in elderly. Clinical outcomes of DI studies were promising. 13 studies including 435 observations (179 CFNG, 182 MNM, 74 DI) were eligible for meta-analysis. The mean change in commissure excursion was 7.15 mm (95% CI: 4.57-9.72) for CFNG, 8.46 mm (95% CI: 6.86-10.06) for MNM, and 5.18 mm (95% CI: 4.01-6.34) for DI. In pairwise comparisons, a significant difference was found between MNM and DI (p = 0.0011), despite the superior outcomes described in DI studies. No statistically significant difference was found in resting and smile symmetry (p = 0.625, p = 0.780).

CONCLUSIONS

CFNG is the most preferred neurotizer, and MNM is a reliable second option. Outcomes of DI studies are promising, but more comparison studies are needed to draw conclusions. Our meta-analysis was limited by incompatibility of the assessment scales. Consensus on a standardized assessment system would add value to future studies.

Optimizing the results of facial animation surgery: Botulinum toxin injection into free functional gracilis flap transfer

Although neuromuscular gracilis transplantation is the best choice for facial reanimation in patients with congenital or inveterate palsy, the results are not completely satisfactory. Ancillary procedures developed to achieve better symmetry of the smile and reduce the hypercontractility of the transplanted muscle have been reported. However, the intramuscular injection of botulinum toxin has not been described for this purpose. Patients undergoing gracilis injections of botulinum toxin after facial reanimation surgery between September 1, 2020, and June 1, 2022, were retrospectively enrolled in this study. We collected photographs taken before and 20-30 days after injection and compared the symmetry of the face using software. Nine patients with a mean age of 23.56 years (range, 7-56 years) were enrolled. Reinnervation of the muscle was provided by the contralateral healthy facial nerve via a sural cross-graft (four patients), by the ipsilateral masseteric nerve (three cases), and by the contralateral masseteric and facial nerve (two). Using Emotrics software, we identified differences in the commissure excursion discrepancy of 3.82 mm, the smile angle discrepancy of 0.084°, and the dental show discrepancy of 1.49 mm; the average difference in the commissure height deviation was 2.26 mm (P = 0.02), and those in the upper- and lower-lip height deviation were 1.05 mm and 1.49 mm, respectively. Gracilis injection of botulinum toxin after gracilis transplantation is a safe and feasible procedure that could be applicable to all patients with asymmetric smiles related to excessive transplant contraction. It yields good esthetic results with little to no related morbidity.

The evolution of facial reanimation techniques

This review article provides an updated discussion on evidence-based practices related to the evaluation and management of facial paralysis. Ultimately, the goals of facial reanimation include obtaining facial symmetry at rest, providing corneal protection, restoring smile symmetry and facial movement for functional and aesthetic purposes. The treatment of facial nerve injury is highly individualized, especially given the wide heterogeneity regarding the degree of initial neuronal insult and eventual functional outcome. Recent advancements in facial reanimation techniques have better equipped clinicians to approach challenging patient scenarios with reliable, effective strategies. We discuss how technology such as machine learning software has revolutionized pre- and post-intervention assessments and provide an overview of current controversies including timing of intervention, choice of donor nerve, and management of nonflaccid facial palsy with synkinesis. We highlight novel considerations to mainstay conservative management strategies and examine innovations in modern surgical techniques with a focus on gracilis free muscle transfer. Innervation sources, procedural staging, coaptation patterns, and multi-vector and multi-muscle paddle design are modifications that have significantly evolved over the past decade.

Using the serratus anterior free flap for dynamic facial reanimation: Systematic review

It was the purpose of this study to evaluate the role of the serratus anterior free flap (SAFF) with its long thoracic nerve (LTN) as composite flap for dynamic facial reanimation. A total of 10 studies, published between 2004 and 2021, met inclusion criteria. Clinical data of 48 patients were used for the systematic review and analysis. One to three slips were used, mainly as one-stage procedures (n = 39; 81.3%), to create different force vectors. Single or double innervated muscle transfers were utilized in 32 (66.7%) and 16 (33.3%) cases with additionally harvested skin paddles in 4 (8.3%) patients. The LTN was mostly anastomosed to the ipsilateral masseteric nerve (45.8%; n = 22) or to remaining facial nerve branches (37.5%; n = 18), while cross-facial-nerve-grafting was rarely used (16.7%; n = 8). The SAFF as composite flap with different force vectors proved to be a good candidate for immediate dynamic facial reanimation after any midface defects.

The Use of Autologous and Cadaveric Grafts in Rhinoplasty: A Survey Study

BACKGROUND

Both autologous and cadaveric grafts are often used during rhinoplasty to create volume and provide support. Despite discussion in the literature comparing the efficacy, cost-effectiveness, and complication rates between grafting options, it remains unclear which is the superior choice when considering availability, donor site morbidity, and cost. There is a little description of the current use of these materials amongst facial plastic surgeons.

METHODS

A 12 question survey was created, and IRB approval was obtained. The survey was distributed to practicing members of the AAFPRS via their membership listserv.

RESULTS

178 respondents completed the survey for an overall response rate of 17.5%. The most common rhinoplasty graft types used by respondents were autologous septal cartilage (96.6%), autologous auricular grafts (93.8%), autologous rib graft (ARG) (75.8%), and cadaveric rib graft (CRG) (56.7%). Patient comorbidities and performing more than 50 rhinoplasties per year were positively correlated with use of CRG grafts and concerns about complications and cost were negatively correlated.

CONCLUSIONS

While autologous septal and auricular cartilage remain the most common graft choices amongst surveyed facial plastic surgeons, a majority utilize cadaveric rib grafts in their practice. Patient comorbidities, surgery volume, concerns about graft complications, and cost were the chief factors associated with use of cadaveric grafts amongst survey respondents.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Supercharged massetric-facial cross-graft for gracilis reinnervation in unilateral facial palsy treatment

BACKGROUND

The choice of neurotization source for gracilis neuromuscular transplant is a key point in the treatment of unilateral long-standing paralysis. To combine the advantages of different donor nerves and overcome their disadvantages, mixed neurotization sources have been described with encouraging results. The authors present a preliminary report of a novel technique, the "supercharged" cross-graft, a two-step technique consisting of a double powered cross nerve graft provided by a zygomatic branch of the healthy facial nerve and the masseter nerve of the healthy side.

PATIENTS AND METHODS

From January 2015 to December 2019 eight patients, aged between 19 and 61 years old (mean age at surgery 33.62) suffering unilateral established paralysis (congenital or acquired, >24 months) underwent gracilis reinnervation with the supercharged cross grafting technique. Subjects underwent a two-step surgical rehabilitation: in the first operation sural nerve was harvested and used as cross-graft cooptated by healthy side facial nerve branch and masseteric nerve. During second procedure gracilis neuromuscular transplant was performed reinnervarting the muscle with the cross-graft. Patients were evaluated using Emotrics software, which allowed for automated facial measurements on post-operative pictures taken at the last follow-up. The results of the different poses were compared to assess the contribution to smile excursion by the masseter and facial nerve, together and separately. Finally, we analyzed spontaneous smile to assess whether masseteric contribution is used in daily life.

RESULTS

No major or minor complications occurred. Follow-up time ranged from 12 to 41 months, with a mean of 22.75 months. A good commissure excursion (mean 33.84 mm) was obtained during smile with no teeth clenching (without masseter activation), as well as during teeth clenching without smiling (activation of gracilis only - mean 32.55). When smiling and biting simultaneously the excursion was greater than the single two components (mean 35.91). In spontaneous smile, commissure excursion was higher (mean 34.23) than that provided by only the facial nerve (smile only) in most patients.

CONCLUSIONS

This novel technique of mixed neurotization for gracilis transplant shows consistent results with powerful contraction and good smile coordination. It also allows us to extend the indications for mixed neurotization techniques.

Temporalis Tendon Transfer Versus Gracilis Free Muscle Transfer: When and Why?

Temporalis tendon transfer (T3) and gracilis free muscle transfer (GFMT) are popular techniques in lower facial rehabilitation when reinnervation techniques are unavailable. T3 involves a single-stage outpatient procedure resulting in immediate improvement in resting symmetry and a volitional smile. GFMT allows a spontaneous smile, customized vectors, and increased excursion but requires longer surgical time, a delay before movement, and specialized equipment. Ultimately, shared decision making between the clinician and patient should focus on the patient's goals and unique medical condition.

Artificial Intelligence-Driven Video Analysis for Novel Outcome Measures After Smile Reanimation Surgery

Background: Since facial paralysis is a dynamic condition, the analysis of still photographs is not sufficient for measurement of facial reanimation outcomes. This study aimed at evaluating an artificial intelligence (AI)-driven software as a novel video assessment tool for smile reanimation surgery and at comparing it with the Terzis score. Methods: Patients with facial paralysis undergoing smile reanimation surgery between January 2008 and April 2020 were eligible for this retrospective study. Inclusion criteria were at least 6 months of follow-up and availability of both pre- and post-operative video documentation. The software output was given as intensity score (IS) values between 0 and 1, representing emotions/action units (AUs) that are absent or fully present, respectively. Results: During the study period, 240 patients underwent facial reanimation surgery, of whom 63 patients met the inclusion criteria. Postoperatively, the median IS of the happiness emotion and lip corner puller AU increased significantly (p < 0.001). There was a positive correlation of Terzis score with the IS of happiness emotion (r = 0.8) and lip corner puller AU (r = 0.74). Conclusions: The novel AI-driven video analysis is strongly correlated with the Terzis score and shows promise for objective functional outcome evaluation after smile reanimation surgery.

Physical Therapy for Iatrogenic Facial Paralysis: A Systematic Review

Importance

Facial paralysis (FP) after surgery has substantial functional, emotional, and financial consequences. Most iatrogenic FP is managed by watchful waiting, with the expectation of facial function recovery. A potential treatment is physical therapy (PT).

Objective

To investigate whether noninvasive PT compared with no PT or other intervention improves facial nerve outcomes in adults with iatrogenic FP.

Evidence Review

Patients with noniatrogenic FP, facial reanimation surgery, and invasive adjunctive treatments (acupuncture or botulinum toxin injection) were excluded. A systematic review was conducted for records discussing iatrogenic FP and PT; a search for these records was performed using Ovid MEDLINE (1946-2019), Embase (1947-2019), Scopus (1823-2019), Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, World Health Organization International Clinical Trials Registry Platform (2004-2019), and ClinicalTrials.gov (1997-2019). The references of all the included articles were also assessed for eligible studies. All human participant, English-language study designs with at least 2 cases were included. Quality assessment was performed using the Methodological Index for Non-randomized Studies (MINORS) and the revised Cochrane Risk of Bias 2 (RoB 2) tool for randomized controlled trials. All search strategies were completed on May 16, 2019, and again on October 1, 2019.

Findings

Fifteen studies (7 of which were retrospective cohort studies) and 313 patients with iatrogenic FP were included in the systematic review. Most iatrogenic FP (166 patients [53%]) was associated with parotidectomy; traditional PT (ie, facial massage) was the most common intervention (196 patients [63%]). The use of various facial grading systems and inconsistent reporting of outcomes prevented direct comparison of PT types.

Conclusions and Relevance

Because of heterogeneity in reported outcomes of facial nerve recovery, definitive conclusions were unable to be made regarding the association between PT and outcomes of iatrogenic FP. Physical therapy probably has benefit and is associated with no harm in patients with iatrogenic FP.

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.