The sternohyoid muscle flap for new dynamic facial reanimation technique: Anatomical study and clinical results

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.

Dynamic Repair Surgery for Late-Stage Facial Paralysis: Advances in Restoring Movement and Function

Purpose: Facial paralysis results from congenital or acquired facial nerve damage, leading to significant cosmetic and functional deficits. Surgical resection of parotid and midface tumors can cause facial paralysis, necessitating effective treatment strategies. This review addresses the challenge of restoring movement and function in late-stage facial paralysis, focusing on dynamic repair techniques involving nerve and muscle transplantation. Methods: The review encompasses studies on dynamic repair surgery for late facial paralysis, including techniques such as local muscle flap with pedicle transfer, vascularized nerve flap with pedicle transfer, and multiple muscle flap procedures. A systematic literature search was conducted using PubMed, Web of Science, and Google Scholar, covering studies from 2000 to 2024. Keywords included "dynamic repair", "late-stage facial paralysis", "nerve and muscle transplantation", "muscle flap", and "tendon transposition". Included were clinical studies, systematic reviews, and meta-analyses reporting surgical outcomes. Exclusion criteria included studies with insufficient data and non-peer-reviewed articles. Results: Dynamic repair techniques involving nerve and muscle transplantation are essential for treating late-stage facial paralysis. Each surgical method has strengths and limitations. The masseter muscle flap demonstrates high success rates, although it can cause horizontal tension and jaw contour issues. The temporalis muscle flap is effective for smile restoration but may lead to temporal concavity. The gracilis muscle flap is widely used, especially with dual nerve innervation, showing high success in spontaneous smiles but requiring a longer recovery period. The latissimus dorsi flap is effective but can cause edema and shoulder issues. The serratus anterior free flap offers flexibility with precise vector positioning but may not achieve adequate lip elevation and can cause cheek swelling. Combined multi-flap surgeries provide more natural facial expressions but increase surgical complexity and require advanced microsurgical skills. Conclusions: Dual nerve innervation shows promise for restoring spontaneous smiles. One-stage surgery offers faster recovery and reduced financial burden. Comprehensive patient evaluation is crucial to select the most suitable surgical method. Dynamic repair techniques involving nerve and muscle transplantation provide effective solutions for restoring function and aesthetics in late-stage facial paralysis. Future research should focus on long-term outcomes, patient satisfaction, and standardizing surgical protocols to optimize treatment strategies.

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.

Pediatric Facial Reanimation

Pediatric facial palsy is rare but severely debilitating and results in profound functional, developmental, psychosocial, and esthetic consequences. Identifying the specific cause of the palsy is important in directing the treatment course. The most common etiologies of pediatric facial palsy are distinct from those of adults. Facial reanimation interventions are targeted to address the zones of the face, with oral/smile rehabilitation the most common region requiring intervention in pediatric patients. Gracilis microneurovascular free tissue transfer is safe and highly effective in the pediatric population, providing significant functional, psychosocial, and esthetic benefits.