Cross-facial nerve anastomosis in the treatment of facial paralysis: a preliminary report on 10 cases

Anatomic and histomorphometric study of the nerve to the vastus lateralis in cadaver for its clinical application in facial reanimation

BACKGROUND

The innervated vastus lateralis flap (IVLF) is a barely used possibility for facial palsy reconstruction because of its thickness compared to the gracilis, latissimus dorsi, and pectoralis minor flaps. The aim of this study is to perform a precise description of the intramuscular distribution of the nerve motor branches and its relationship with the vascular pedicle in order to harvest a segmental muscle flap with the best contractile strength to restore facial reanimation.

METHODS

The study was performed on 16 adult cadaver thighs identifying the vastus lateralis muscle and the distribution and relationships of its neurovascular pedicle and branches. We evaluated where the nerve pierced the muscle and the course of the nerve within it. Transverse segments of the nerve were obtained from the proximal and distal ends of the nerve and stained using anti-ChAT (Choline acetyltransferase) antibodies which are specific of motor neurons.

RESULTS

A nerve for the vastus lateralis from the posterior division of the femoral nerve divided into 2 branches in 56% of cases; the principal branch coursed along the vascular pedicle and pierced the muscle more proximally than the respective vessels, and a minor branch that pierced the muscle 25-60 mm proximally. There were 3 main intramuscular branches. The nerve length (mean 132.65 ± 22.89 mm) allowed to reach the contralateral side of the face in almost all cases (95%). The mean ChAT positive fibers was 351.0 ± 92.4/mm² at the proximal end, and 270.3 ± 87.9/mm² at the distal end (p = 0.49). The number of ChAT negative fibers was higher than ChAT positive in both proximal and distal ends of the nerve.

CONCLUSION

We propose the IVLF as a one-step surgical flap for facial paralysis reanimation due to the constant neurovascular pattern and lengthy pedicle. The amount of motor fibers in several segments of the nerve is appropriate to produce a powerful contraction for dynamic reconstruction.

Anatomical study of the masseteric and obturator nerves: Application to face transplant and reanimation procedures

The masseteric nerve (MN) and the anterior branch of the obturator nerve (ON) that innervate the transferred gracilis muscle have proved highly efficient for reanimating paralyzed facial muscles when muscle transfer is required. Previous researchers have published the total axonal load for myelinated fibers in both nerves. However, the real motor axonal load has not been established. We performed the study on 20 MN and 13 ON. The segments of the MN and the ON were embedded in paraffin, sectioned at 10 μm, and stained following a standard immunohistochemical procedure using anti-choline acetyltransferase to visualize the motor fibers. The MN has a higher axonal load than the ON. There were statistically significant differences between the axonal load of the proximal segment of the MN and the ON. These findings confirm that end-to-end anastomoses between the MN and the ON should preferably use the proximal segment. However, MN neurotomy should ideally be performed between the proximal and distal segments, preserving innervation to the deep fascicles. Our results show that the MN is ideal as a donor motor nerve for reinnervating transplanted muscle for dynamic reanimation of the paralyzed face. The neurotomy should ideally be performed between the first and second collateral branches of the MN. Clin. Anat. 32:612-617, 2019. © 2019 Wiley Periodicals, Inc.

Technique evolution for facial paralysis reconstruction using functioning free muscle transplantation--experience of Chang Gung Memorial Hospital

The author performed facial reanimation by using functioning free muscle transplantation in 116 cases from 1986 to 2000. Three consecutive five-year periods are presented in relation to each stage of the author's technical improvement. The first five years bulkiness and asymmetrical smiling with weak gum exposure were encountered and required correction. The second five years was a period of technical improvement, but with residual deformities. The third five-year period was one of technique refinement. The author extended the utility of the gracilis for different and more challenged problems, such as the use of a muscle plus skin two-unit composite flap connected by the septoperforator nutrients, not only for facial reanimation but also for intra-oral contracture release or extra-oral facial soft tissue and skin deficits replacement.

Current principles in microsurgical nerve repair

Micronerve reconstruction of motor and sensitive nerves in the head and neck area currently has an established range of indications. Surgical procedures always follow a strict order, beginning with external neurolysis. In cases of complete separation of the nerve stumps or when tensionless coaptation of nerve ends can not be achieved, nerve grafts from suitable donor sites, for example the sural nerve, have to be interposed. Good functional results can be obtained following reconstruction of motor nerves, as with the accessory or the facial nerve. In contrast, reconstruction of sensory nerves has a lower success rate but very often leads to a subjective improvement of symptoms for the patient. In long-standing facial palsy with atrophy of the facial musculature, neurovascularly reanastomosed muscle grafts offer a good option.

Cross-face reanimation of the paralysed face, with a single stage microneurovascular gracilis transfer without nerve graft: a preliminary report

This paper describes a method of cross-face reanimation of the paralysed face by a single stage transfer of gracilis. In this method, the nerve to the gracilis is kept long and tunnelled across the upper lip and joined directly to branches of the facial nerve on the normal side. The method avoids the need for a nerve graft and shortens the period of rehabilitation by 12 months. The results in 3 cases were good in 2 cases and fair in 1 case.

Reanimation for facial palsy using gracilis muscle grafts

Twelve patients have been reviewed at least 2 years after gracilis muscle transfer, preceded by crossface nerve grafting, for complete unilateral facial palsy. Levels of satisfaction among the patients were good. Examination showed all had voluntary movement of the graft which could produce reasonable mouth symmetry in most patients. However, the involuntary spontaneity and expressive movements were not so satisfactory, though still worthwhile. The technique and some lessons learned from this experience are discussed. It appears from electromyographic studies that continuing innervation and activity can occur in these grafts for many years postoperatively.

Cross-facial nerve transplants: why are spontaneous smiles not restored?

The technique of cross-facial nerve transplantation (CFNT), with or without the addition of vascularised muscle, has made it possible to achieve some voluntary movement of the paralysed side of the face in patients with unrecovered facial palsy. If normal faces are studied during conversation, it can be seen that there are two types of movement of the lips--those of emotional expression and those involved in the formation of vowel sounds and labial consonants. Smiles themselves can be classified roughly according to their length of muscle contraction--the longer "definitive" smile, and the shorter "flash" smile. It is the synergistic facial movement of the unpremeditated "flash" smile and the small movements in the formation of the vowel sounds and labial consonants which fail to occur in patients reanimated by revascularised, reinnervated muscle, despite the return of voluntary contraction and resting facial tone. This study was undertaken to try to determine why these synergistic facial movements of short duration are so difficult to achieve.