Hypoglossal-Facial Side-to-End Neurorrhaphy With Concomitant Masseteric-Zygomatic Nerve Branch Coaptation and Muscle Transfer for Facial Reanimation: Technique and Case Report

Nerve to the zygomaticus major muscle: An anatomical study and surgical application to smile reconstruction

Smile reconstruction using the branches that supply the zygomaticus major muscle as a motor source is an established procedure in facial reanimation surgery for facial paralysis. However, the anatomy of the nerve to the muscle remains unclear. Therefore, we herein examined the topographical anatomy of the nerve to the zygomaticus major muscle to obtain more detailed information on donor nerve anatomy. Preserved cadaver dissection was performed under a microscope on 13 hemifaces of 8 specimens. The branches that innervate the zygomaticus major muscle and their peripheral routes medial to the muscle were traced and examined. A median of four (ranges 2-4) branches innervated the zygomaticus major muscle. The proximal two branches (near the muscle origin) arose from the zygomatic branch, the second of which was the major branch. The distal branches (near the oral commissure) arose from the buccal branch or zygomaticobuccal plexus. The vertical distance from the caudal margin of the zygomatic arch to the major branch intersecting point was 19 ± 4.0 mm, while the horizontal distance parallel to the Frankfort plane was 29 ± 5.2 mm. The proximal two branches innervating the zygomaticus major muscle were detected in the majority of specimens. The anatomical findings obtained herein on the nerve to the zygomaticus major muscle will allow for more reliable donor selection in facial reanimation surgery.

The Selective Trigeminal Nerve Motor Branching Transfer: an Preliminary Clinical Application for Facial Reanimation

OBJECTIVE

To investigate the effectiveness and feasibility of selective trigeminal nerve motor branching in the repair of facial palsy.

MATERIALS AND METHODS

The clinical data of patients with advanced facial palsy from 2016 to 2021 were retrospectively analyzed, including pictures and videos before and 18 months after surgery. The House-Brackmann grading system was used to evaluate facial nerve function before and after repair, and the symmetry scale of oral commissure at rest and Terzis' smile functional evaluation scale were used to qualitatively assess the symmetry of the mouth angle and smile function. The distance of oral commissure movement was assessed to evaluate the dynamic repair effect, and the FaCE facial muscle function scale was used to assess patients' subjective perception before and after surgery.

RESULTS

A total of four patients were included in the study, all of whom showed signs of recovery of facial nerve function within six months. In all four cases, significant improvements were observed in House-Brackmann ratings, the smile function score and the symmetry scale of oral commissure at rest. Compared to the pre-operative period, the four patients demonstrated various degrees of eye-closing function recovery, and a significant improvement in oral commissure movement was observed ( P <0.001). FaCE scores also improved significantly after surgery ( P =0.019).

CONCLUSION

Concurrent selective facial nerve repair with trigeminal branch-facial nerve anastomosis resulted in eye-closing function recovery while improving static and dynamic symmetry, yielding acceptable postoperative results.

Dynamic eyelid reconstruction in facial nerve palsy

The consequences of facial nerve palsy and the secondary inability of eyelid closure and blink may lead to devastating complications for the patient, including blindness. Reconstruction techniques to improve eyelid position and function can be broadly classified into 'static' and 'dynamic' techniques. Generally, ophthalmologists have been familiar with static procedures such as upper eyelid loading, tarsorrhaphy, canthoplasty, and lower eyelid suspension. Recently, dynamic techniques are being increasingly described for patients who require definitive strategies to improve eyelid function, once the initial critical goals of corneal protection and vision preservation have been achieved. The choice of technique(s) is dependent upon the status of the main protractor of the eyelid region, as well as the age of the patient, the patient's morbidities and expectations, and surgeon preference. This review shall first describe the clinical and surgical anatomy relevant to the ophthalmic consequences of facial paralysis and discuss methods of defining function and outcomes. A comprehensive review of dynamic eyelid reconstruction is then presented with a discussion of the literature. These various techniques may not be familiar to all clinicians. It is important that ophthalmic surgeons are aware of all options available for their patients. Furthermore, eye care providers must have an understanding of when referral may be appropriate to provide timely intervention and optimal chances of recovery.

An Anatomical Feasibility Study on the Use of the Hypoglossal and Hemihypoglossal Nerve as a Donor Motor Nerve for Free Functioning Muscle Transfer in Upper Extremity Reconstruction

PURPOSE

Brachial plexus injuries (BPI) with complete root avulsions remains a clinical challenge due to a paucity of nerves available for nerve transfer and innervation of free functioning muscle transfers (FFMT). The hypoglossal and hemihypoglossal nerve has not been studied as a donor nerve option for FFMTs in brachial plexus reconstruction, despite successful outcomes of hypoglossal nerve transfers in facial reanimation surgery. We hypothesized that the hypoglossal nerve could be an appropriate candidate for surgical repair of BPI using FFMT.

METHODS

A cadaveric study was performed to determine the anatomic feasibility of using the hypoglossal and hemihypoglossal nerves as donor nerves to neurotize the gracilis or latissimus dorsi muscle in an FFMT to restore elbow flexion. Twelve cadavers (6 males and 6 females) were studied. The hypoglossal nerve, thoracodorsal nerve, and obturator nerve branches to the gracilis muscle were dissected, measured, and analyzed.

RESULTS

The average length of the hypoglossal nerve was 6.3 ± 0.5 cm in both sexes. The average distance between the lowest point of the hypoglossal nerve and the lateral clavicle was 8.4 ± 1.3 cm in males and 7.7 ± 0.8 cm in females. When the hypoglossal nerve was transected distally, the average distance to the clavicle was 4.5 ± 1.6 cm in males and 3.8 ± 1.5 cm in females.

CONCLUSIONS

The maximum theoretical length of the donor nerve required to perform an adequate FFMT using the hypoglossal nerve was 8.9 ± 1.2 cm, which was well exceeded by the lengths of the thoracodorsal nerve (14.5 ± 1.3 cm) and nerve to the gracilis muscle (12.7 ± 1.7 cm).

CLINICAL RELEVANCE

This cadaveric study demonstrated that the hypoglossal or hemihypoglossal nerves may be used as potential motor donor nerves to innervate a free gracilis or latissimus dorsi muscle transfer for the restoration of elbow flexion via a direct nerve transfer without the need for nerve grafting.

Donors for nerve transplantation in craniofacial soft tissue injuries

Neural tissue is an important soft tissue; for instance, craniofacial nerves govern several aspects of human behavior, including the expression of speech, emotion transmission, sensation, and motor function. Therefore, nerve repair to promote functional recovery after craniofacial soft tissue injuries is indispensable. However, the repair and regeneration of craniofacial nerves are challenging due to their intricate anatomical and physiological characteristics. Currently, nerve transplantation is an irreplaceable treatment for segmental nerve defects. With the development of emerging technologies, transplantation donors have become more diverse. The present article reviews the traditional and emerging alternative materials aimed at advancing cutting-edge research on craniofacial nerve repair and facilitating the transition from the laboratory to the clinic. It also provides a reference for donor selection for nerve repair after clinical craniofacial soft tissue injuries. We found that autografts are still widely accepted as the first options for segmental nerve defects. However, allogeneic composite functional units have a strong advantage for nerve transplantation for nerve defects accompanied by several tissue damages or loss. As an alternative to autografts, decellularized tissue has attracted increasing attention because of its low immunogenicity. Nerve conduits have been developed from traditional autologous tissue to composite conduits based on various synthetic materials, with developments in tissue engineering technology. Nerve conduits have great potential to replace traditional donors because their structures are more consistent with the physiological microenvironment and show self-regulation performance with improvements in 3D technology. New materials, such as hydrogels and nanomaterials, have attracted increasing attention in the biomedical field. Their biocompatibility and stimuli-responsiveness have been gradually explored by researchers in the regeneration and regulation of neural networks.

Human Adipose-Derived Stem Cells Delay Muscular Atrophy after Peripheral Nerve Injury in Rats

INTRODUCTION

Given that denervation atrophy often occurs in muscle after peripheral nerve injury, the effects of injections of human adipose-derived stem cells (hADSCs) and platelet-rich plasma (PRP) into muscle after peripheral nerve injury were examined.

METHODS

hADSCs were isolated from human subcutaneous fat tissue, and PRP was prepared from rat whole blood before injection into a rat sciatic nerve injury model. Muscle atrophy was evaluated by quantitating the gross musculature and muscle fiber area and walking footprint analysis.

RESULTS

At 4 weeks post-surgery, there were significant differences in the sciatic functional index between experimental (injected with hADSCs, PRP, or combined hADSCs + PRP) and non-operated groups (p < 0.0001), but no significant differences were observed between the different treatment groups (p > 0.05). Post hoc Bonferroni tests also showed significant differences in the wet muscle weight ratios of hADSC, PRP, and combined groups compared to PBS group. The gastrocnemius muscle fiber area was larger in hADSC group and the combined group compared to PBS group at 4 weeks post-surgery.

CONCLUSION

The injection of hADSCs delays muscular atrophy after sciatic nerve injury in rats; thus, hADSCs are a promising alternative for regenerating atrophied muscle.