Dual Innervation of Free Functional Muscle Flaps in Facial Paralysis

Dual-Innervated Gracilis Free Functional Muscle Transfers in Facial Palsy Patients: Comparing Long-Term Outcomes between One- versus Two-Stage Procedures

BACKGROUND

 In facial reanimation, dual-innervated gracilis free functional muscle transfers (FFMTs) may have amalgamated increases in tone, excursion, synchroneity, and potentially spontaneity when compared with single innervation. The ideal staging of dual-innervated gracilis FFMTs has not been investigated. We aim to compare objective long-term outcomes following one- and two-stage dual-innervated gracilis FFMTs.

METHODS

 Included were adult patients with facial paralysis who underwent either one- (one-stage group) or two-stage (two-stage group) dual-innervated gracilis FFMT with ≥1 year of postoperative follow-up. Facial measurements were obtained from standardized photographs of patients in repose, closed-mouth smile, and open-mouth smile taken preoperatively, 1 year postoperatively, and 3 years postoperatively. Symmetry was calculated from the absolute difference between the paralyzed and healthy hemiface; a lower value indicates greater symmetry.

RESULTS

 Of 553 facial paralysis patients, 14 were included. Five and nine patients were in the one- and two-stage groups, with mean follow-up time, respectively, being 2.5 and 2.6 years. Within-group analysis of both groups, most paralyzed-side and symmetry measurements significantly improved over time with maintained significance at 3 years postoperatively in closed and open-mouth smile (all p ≤ 0.05). However, only the two-stage group had maintained significance in improvements at 3 years postoperatively in paralyzed-side and symmetry measurements in repose with commissure position (median change [interquartile range, IQR], 7.62 [6.00-10.56] mm), commissure angle (median change [IQR], 8.92 [6.18-13.69] degrees), commissure position symmetry (median change [IQR], -5.18 [-10.48 to -1.80] mm), commissure angle symmetry (median change [IQR], -9.78 [-11.73 to -7.32] degrees), and commissure height deviation (median change [IQR], -5.70 [-7.19 to -1.64] mm; all p ≤ 0.05). In the between-group analysis, all measurements were comparable in repose, closed-mouth smile, and open-mouth smile (all p > 0.05).

CONCLUSION

 Long-term outcomes demonstrate that both one- and two-stage dual-innervated gracilis FFMTs significantly improve excursion, but only two-stage reconstruction significantly improves resting tone.

Neurofibromatosis Type II and Facial Paralysis: Clinical Evaluation and Management

BACKGROUND

Facial paralysis secondary to neurofibromatosis type 2 (NF2) presents the reconstructive surgeon with unique challenges because of its pathognomonic feature of bilateral acoustic neuromas, involvement of multiple cranial nerves, use of antineoplastic agents, and management. Facial reanimation literature on managing this patient population is scant.

METHODS

A comprehensive literature review was performed. All patients with NF2-related facial paralysis who presented in the past 13 years were reviewed retrospectively for type and degree of paralysis, NF2 sequelae, number of cranial nerves involved, interventional modalities, and surgical notes.

RESULTS

Twelve patients with NF2-related facial paralysis were identified. All patients presented after resection of vestibular schwannoma. Mean duration of weakness before surgical intervention was 8 months. On presentation, one patient had bilateral facial weakness, 11 had multiple cranial nerve involvement, and seven were treated with antineoplastic agents. Two patients underwent gracilis free functional muscle transfer, five underwent masseteric-to-facial nerve transfer (of whom two were dually innervated with a crossfacial nerve graft), and one patient underwent depressor anguli oris myectomy. Trigeminal schwannomas did not affect reconstructive outcomes if trigeminal nerve motor function on clinical examination was normal. In addition, antineoplastic agents such as bevacizumab and temsirolimus did not affect outcomes if stopped in the perioperative period.

CONCLUSIONS

Effectively managing patients with NF2-related facial paralysis necessitates understanding the progressive and systemic nature of the disease, bilateral facial nerve and multiple cranial nerve involvement, and common antineoplastic treatments. Neither antineoplastic agents nor trigeminal nerve schwannomas associated with normal examination affected outcomes.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

An ACS-NSQIP Data Analysis of 30-Day Outcomes Following Surgery for Bell's Palsy

BACKGROUND

There exists a paucity of large-scale, multi-institutional studies that investigate the outcomes of surgery for Bell's palsy (BP). Here, we utilize a large, multi-institutional database to study the risk factors and early-stage outcomes following surgical procedures in BP.

METHODS

We reviewed the American College of Surgeons National Surgical Quality Improvement Program database (2008-2019) to identify patients who underwent surgery for the diagnosis of BP. We extracted data on comorbidities and preoperative blood values, and 30-day postoperative outcomes.

RESULTS

Two hundred fifty-seven patients who underwent surgery for BP symptoms over the 12-year review period were identified. Muscle grafts (n=50; 19%) and fascial grafts (n=48; 19%) accounted for the majority of procedures. The most common comorbidities were hypertension (n=89; 35%) and obesity (n=79; 31%). Complications occurred in 26 (10.1%) cases. Additionally, length of hospital stay was significantly associated with both surgical and medical complications (3.9±4.7 versus 1.5±2.0; P <0.01) and (3.2±3.8 versus 1.4±2.0; P <0.01), respectively. Preoperative creatinine, blood urea nitrogen, and alkaline phosphatase were identified as potential predictors of poor postoperative outcomes.

CONCLUSION

Based on multi-institutional analysis, complication rates following surgery for BP were found to be overall low and seen to correlate with length of hospital stay. Reoperations and readmissions were the most frequent complications after surgery for BP. The preoperative evaluation of routine laboratory values may help refine patient eligibility and risk stratification. In addition, our findings call for future large-scale prospective studies in the field of facial palsy surgery to further improve the quality of care and optimize perioperative protocols.

Restoring the spontaneous smile through free functional muscle transfer. A systematic review and meta-analysis of the last twenty years' experience

BACKGROUND

The recovery of the spontaneous smile has become a primary focus in facial reanimation surgery and its major determinant is the selected neurotizer. We aimed to compare the spontaneity outcomes of the most preferred neurotization methods in free functional muscle transfer for long-standing facial paralysis.

METHODS

The Embase, Ovid Medline, and PubMed databases were queried with 21 keywords. All clinical studies from the last 20 years reporting the postoperative spontaneity rate for specified neurotization strategies [cross-face nerve graft (CFNG), contralateral facial nerve (CLFN), motor nerve to the masseter (MNM), and dual innervation (DI)] were included. A meta-analysis of prevalence was performed using Freeman-Tukey double arcsine transformation, I2 statistic, and generic inverse variance with a random-effects model. Risk Of Bias In Non-randomized Studies of Interventions and Newcastle-Ottawa scale were used to assess bias and study quality.

RESULTS

The literature search produced 2613 results and 473 unique citations for facial reanimation. Twenty-nine studies including 2046 patients were included in the systematic review. A meta-analysis of eligible data (1952 observations from 23 studies) showed statistically significant differences between the groups (CFNG: 0.94; 95% confidence interval [CI], 0.76-1.00, CLFN: 0.91; 95% CI, 0.49-1.00, MNM: 0.26; 95% CI, 0.05-0.54, DI: 0.98; 95% CI, 0.90-1.00, P < 0.001). In pairwise comparisons, statistically significant differences were found between MNM and other neurotization strategies (P < 0.001 in CFNG compared with MNM, P = 0.013 for CLFN compared with MNM, P < 0.001 for DI compared with MNM).

CONCLUSIONS

DI- and CLFN-driven strategies achieved the most promising outcomes, whereas MNM showed the potential to elicit spontaneous smile at a lower extent. Our meta-analysis was limited primarily by incongruency between spontaneity assessment systems. Consensus on a standardized tool would enable more effective comparisons of the outcomes.

Muscle transposition and free muscle transfer in facial nerve reanimation

PURPOSE OF REVIEW

This review highlights recent advances in facial reanimation surgery particularly related to muscle transposition and free functional muscle transfer (FFMT).

RECENT FINDINGS

FFMT and muscle transposition are mainstays in the treatment of chronic facial paralysis. Recent literature evaluates single versus dual innervated FFMT, reanimation of the periocular region and lower lip depressors, and indications for such methods over gold standard FFMT techniques. New donor sites for muscle transposition and FFMT are also described.

SUMMARY

Gracilis FFMT (GFMT) continues to be the gold standard in dynamic facial reanimation for patients with chronic facial paralysis. Muscle transposition should be considered in older patients, those medically unfit for long operative procedures, and individuals who prefer more immediate results. With respect to FFMT, described nerve coaptation patterns, surgical stages, and donor muscle choice vary. Standardization of data reporting and outcome measures is needed in future studies.

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.

Artificial intelligence-based numerical analysis of the quality of facial reanimation: A comparative retrospective cohort study between one-stage dual innervation and single innervation

This study aimed to investigate the difference in facial reanimation surgery using functional gracilis muscle transfer between the masseteric nerve alone and its combined use with cross face nerve graft (CFNG), which has not been explored before. A novel analysis method based on artificial intelligence (AI) was employed to compare the outcomes of the two approaches. Using AI, 3-dimensional facial landmarks were extracted from 2-dimensional photographs, and distance and angular symmetry scores were calculated. The patients were divided into two groups, with Group 1 undergoing one-stage CFNG and masseteric nerve dual innervation, and Group 2 receiving only masseteric nerve. The symmetry scores were obtained before and 1 year after surgery to assess the degree of change. Of the 35 patients, Group 1 included 13 patients, and Group 2 included 22 patients. The analysis revealed that, in the resting state, the change in the symmetry score of the mouth corner showed distance symmetry (2.55 ± 2.94, 0.52 ± 2.75 for Group 1 and Group 2, respectively, p = 0.048) and angle symmetry (1.21 ± 1.43, 0.02 ± 0.22 for Group 1 and Group 2, respectively, p = 0.001), which were significantly improved in Group 1, indicating a more symmetric pattern after surgery. In the smile state, only the angle symmetry was improved more symmetrically in Group 1 (3.20 ± 2.38, 1.49 ± 2.22 for Group 1 and Group 2, respectively, p = 0.041). Within the limitations of the study it seems that this new analysis method enabled a more accurate numerical symmetry score to be obtained, and while the degree of mouth corner excursion was sufficient with only the masseteric nerve, accompanying CFNG led to further improvement in symmetry in the resting state.

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.