Medial antebrachial cutaneous nerve: a new donor graft for repair of facial nerve defects at the skull base

Repair and regeneration of peripheral nerve injuries that ablate branch points

The peripheral nervous system has an extensive branching organization, and peripheral nerve injuries that ablate branch points present a complex challenge for clinical repair. Ablations of linear segments of the PNS have been extensively studied and routinely treated with autografts, acellular nerve allografts, conduits, wraps, and nerve transfers. In contrast, segmental-loss peripheral nerve injuries, in which one or more branch points are ablated so that there are three or more nerve endings, present additional complications that have not been rigorously studied or documented. This review discusses: (1) the branched anatomy of the peripheral nervous system, (2) case reports describing how peripheral nerve injuries with branched ablations have been surgically managed, (3) factors known to influence regeneration through branched nerve structures, (4) techniques and models of branched peripheral nerve injuries in animal models, and (5) conclusions regarding outcome measures and studies needed to improve understanding of regeneration through ablated branched structures of the peripheral nervous system.

Research trends and perspectives on immediate facial reanimation in radical parotidectomy (Review)

For patients diagnosed with advanced malignant parotid tumour, radical parotidectomy with facial nerve sacrifice is part of the treatment. Multiple surgical techniques have been developed to cure facial paralysis in order to restore the function and aesthetics of the face. Despite the large number of publications over time on facial nerve reanimation, a consensus on the timing of the procedure or the donor graft selection has remained to be established. Therefore, the aim of the present study was to conduct a bibliometric analysis to identify and analyse scientific publications on the reconstruction of the facial nerve of patients who underwent radical parotidectomy with facial nerve sacrifice. The analysis on the topic was conducted using the built-in tool of the Scopus database and VOSviewer software. The first 100 most cited articles were separately reviewed to address the aim of the study. No consensus was found regarding the recommended surgical techniques for facial nerve reanimation. The most used donor cranial nerves for transfer included the following: Masseteric branch of the V nerve, contralateral VII nerve with cross-face graft, the XI nerve and the XII nerve. The best timing of surgery is also controversial depending on pre-exiting pathology and degree of nerve degeneration. However, most of the clinical experience suggests facial nerve restoration immediately after the ablative procedure to reduce complications and improve patients' quality of life.

Surgical Anatomy of the Medial Antebrachial Cutaneous Nerve: Clinical Application in Ulnar Nerve Decompression Surgery in the Elbow

Introduction Lesion to the posterior branch of the medial antebrachial cutaneous nerve (MACN) is one of the causes of revision of the ulnar nerve decompression surgery in the elbow.

To avoid the morbidity associated with this injury, cadaver dissections were performed to identify this branch in its course through the ulnar tunnel.

Methods We included 20 upper extremities of fresh cadaveric specimens. The posterior branch of the MACN was identified proximal to medial epicondyle and followed past the ulnar tunnel. The number of ramifications and their coordinates were recorded in a Cartesian plane, with the medial epicondyle as the central point.

Results The posterior branch passed proximal and posterior to the medial epicondyle in all specimens, except one. The average of the adjusted x value is of 30 mm, and of the adjusted y value is -18 mm. Additionally, we determined that the posterior branch passes at an average angle of 30° with respect to the x axis.

Conclusion The anatomical descriptions of this branch focused on surgical release of the ulnar nerve in the elbow are limited, and measures are only described in the horizontal plane (from proximal to distal). Schematizing the anatomy of this branch in its course throughout the ulnar tunnel will facilitate its identification during the procedures. However, variability and asymmetry in the branching pattern should be considered.

Contralateral C7 transfer via both ulnar nerve and medial antebrachial cutaneous nerve to repair total brachial plexus avulsion: a preliminary report

Aim: After brachial plexus injuries, sacrifice of the contralateral C7 (cC7) root from the non-injured side is well tolerated and various schemes to innervate the injured side from the cC7 root have been used. Objective: To demonstrate the surgical outcomes from transferring the cC7 to the affected side via both the ulnar nerve and medial antebrachial cutaneous nerve (MACN).Methods: A retrospective study of 16 adult patients sustaining total brachial plexus avulsion who underwent this procedure. The British Medical Research Council (MRC) grading system and the disabilities of the arm, shoulder, and hand (DASH) questionnaire scoring were used to evaluate the recovery.Results: About 68.75% of the patients achieved functional recovery of elbow flexion to M3 or better and 43.75% achieved motor recovery of wrist and finger flexion to M3 or better. Sensation in the median nerve territory recovered to S2 or better in 68.75%. The DASH scores after surgery were significantly lower than those before surgery.Conclusions: cC7 transfer via both ulnar and MACNs is an effective and safe procedure in patients sustaining total injuries of brachial plexus.

Intracranial Facial Nerve Grafting in the Setting of Skull Base Tumors: Global and Regional Facial Function Analysis and Possible Implications for Facial Reanimation Surgery

BACKGROUND

Reconstructive surgeons may encounter patients presenting after intracranial facial nerve resection and grafting in the setting of skull base tumors, who inquire regarding progression, final facial function, and need for future operations. Study goals were to analyze global and regional facial function using established grading systems and videography, while examine variables possibly affecting outcomes.

METHODS

Between 1997 and 2012, 28 patients underwent intracranial nerve grafting. Fifteen were prospectively evaluated by three facial nerve physical therapists with the Facial Nerve Grading System 2.0 and the Sunnybrook Facial Grading Score for function and the Facial Disability Index for quality of life. Still photographs and videography were used to assess quality of motion and tone, while demographic and medical variables were analyzed regarding their effect on end results.

RESULTS

Average patient age was 41.9 years (range, 22 to 66 years), and there were 10 women and five men. Average time interval between nerve grafting and evaluations was 42.9 months (range, 12 to 146 months). Both grading scores demonstrated best outcomes in the periorbita and worst outcomes in the brow. Buccinator muscle tone also improved. The average total Facial Disability Index was 67.5 percent. Although not statistically significant, the data suggest that nerve gap length affected total resting symmetry and voluntary movement, whereas preoperative palsy and age may affect total resting symmetry. Perioperative radiation therapy, tumor type, donor nerve, and coaptation technique were not found to affect outcomes.

CONCLUSIONS

Intracranial facial nerve grafting largely provides better resting tone and facial symmetry, potentially improving end results of future intervention; however, overall voluntary facial motion is poor.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Comparison of vocal outcome following two different procedures for immediate RLN reconstruction

The objective of this study was to compare time-dependent improvements in phonatory function and stroboscopic findings following two different procedures for immediate reconstruction of the recurrent laryngeal nerve (RLN) during neck tumor extirpation. Seventeen patients with neck tumors, consisting of advanced thyroid cancer (n = 15), metastatic neck lymph nodes from other malignant lesions (n = 2), underwent resection of the primary lesion and involved RLN. Immediate RLN reconstruction by either: (1) ansa cervicalis nerve (ACN) to RLN anastomosis (n = 8); or (2) placement of the great auricular nerve (GAN) between the cut ends of the RLN (n = 9) was performed from 2000 to 2011. Phonatory function [maximum phonation time, mean airflow rate (MFR), jitter, and shimmer) and stroboscopic findings (regularity, amplitude, and glottal gap) were examined at 1, 6, and 12 months postoperatively. Stroboscopic findings were assessed by two otolaryngologists and one speech pathologist. There were no significant differences in any parameter for either phonatory function or stroboscopic findings between ACN and GAN with the exception of jitter and shimmer, in which ACN was superior to GAN at 1 month postoperatively. All parameters improved significantly between 1 and 12 months postoperatively for both phonatory function and stroboscopic findings (P < 0.05). Either method of immediate RLN reconstruction at the time of neck tumor extirpation (i.e., ACN or GAN) provided both excellent long-term postoperative phonatory function and stroboscopic findings, and there was little difference in vocal outcome between the two procedures.

Posterior interosseus nerve vs. medial cutaneous nerve of the forearm: differences in digital nerve reconstruction

Digital nerve defects are common in hand trauma and for primary or secondary nerve reconstruction, the autologous nerve graft remains the gold standard. This study compares the regeneration results and donor side morbidity of either the posterior interosseus nerve (PIN) graft or the medial antebrachial cutaneous nerve (MACN) graft. 16 patients (group A, age 43 ± 13 years) with digital nerve defects were treated with a PIN graft and 12 patients (group B, age 40 ± 15 years) received a MACN graft. The average nerve gap was 22 mm in each group. After a follow-up of 15 ± 8 months in group A, S4-sensibility were measured in 9 cases, S3+ in 5 cases and in 1 case S2 and S0. Up to an inconspicuously scar in projection of the fourth extensor-tendon compartment, there was no significant donor side morbidity. In group B, a S4-senibility has been obtained in 4 cases, S3+ in 5 cases, S3, S2 and S0 in each 1 case after a follow-up of 16 ± 11 months. Regarding the donor side morbidity, almost all patients complained about a disturbing scar formation and unpleasant paresthesia at the forearm down to the rascetta. Neuroma-associated pain has been detected in 4 cases. Although there has been no significant difference in terms of nerve regeneration, we recommend the use of the PIN graft for digital nerve reconstruction, since harvesting this nerve is fast and easy and without any donor side morbidity compared to the MACN graft.

Thoracodorsal nerve graft for reconstruction of facial nerve branching

OBJECT

Surgical treatment of parotid malignancies may frequently involve facial nerve amputation to achieve oncological radical resection. The entire facial nerve branching from its exit from the stylomastoid foramen to the periphery of the gland is often sacrificed. The first reconstructive strategy is the immediate reconstruction of the facial nerve by directly anastomosing the trunk of the facial nerve to its distal branches by interpositional nerve grafting. The present study was performed to determine the adequacy of thoracodorsal nerve grafting for immediate repair of the facial nerve. The anatomical features of the thoracodorsal nerve make it particularly appropriate to match its trunk to the stump of the facial nerve at its exit from the stylomastoid foramen. Up to seven branches of the thoracodorsal nerve may be distally anastomosed to the severed distal branches of the facial nerve. More complex reconstruction may be addressed simultaneously by contemporary harvesting a de-epithelialized free flap from the same site based on thoracodorsal vessel perforators and preparing a rib graft from the same donor site.

METHODS

Between October 2003 and August 2010, seven patients affected by parotid tumors (6 with parotid malignancies and 1 with multiple recurrences of pleomorphic adenoma) underwent radical parotidectomy with intentional sacrifice of the facial nerve to obtain oncological radical resection. In all patients, the facial nerve was reconstructed with an interpositional thoracodorsal nerve graft. In four patients, a de-epithelialized free flap based on the latissimus dorsi was transposed to cover soft tissue defects. Moreover, two of these patients also required a rib graft to reconstruct both the condyle and ramus of the mandible. With the exception of one patient affected by recurrent pleomorphic adenoma, all patients underwent radiotherapy after surgical treatment.

RESULTS

All patients in our study recovered mimetic facial function. Facial muscles showed clinical signs of recovery within 5-14 (mean: 7.8) months, with varying degrees of mimetic restoration, and almost complete facial symmetry at rest in all patients. The House-Brackmann final score was I in two patients, II in two patients, and III in three patients.

CONCLUSIONS

A thoracodorsal nerve graft to replace extratemporal facial nerve branching is a valid alternative technique to multiple classical nerve grafts, with good matching at both the proximal and distal anastomoses.

A comparative microanatomical study on cross sections of medial and lateral cutaneous nerves of forearm at the antecubital fossa: a cadaveric study

BACKGROUND

The anterior branch of the medial antebrachial cutaneous nerve of the forearm (AMACN) and the lateral antebrachial cutaneous nerve of the forearm (LACN) are used as potential donor grafts for repairing sensory nerves. A higher percentage of connective tissue plays an important role in predicting prognosis after nerve repair. The aim is to perform a comparative study on cross-sectional microanatomy and age related changes in non-fascicular components of the AMACN and LACN.

METHODS

Thirty six fresh human (from both sides of 14 male and 4 female) cadaveric AMACN and LACN were collected at antecubital fossae and studied at different magnifications for morphometric analysis (total cross-sectional area (Asc), fascicular area (Af) and non-fascicular area (Anonf)), after histological (Masson's trichrome stain) processing.

RESULTS

AMACN and LACN belong to polyfascicular type and showed differences in amount of connective and adipose tissues in non-fascicular areas. In the AMACN, there was less adipose tissue (19.38% in Asc and 25.57% in Anonf) with more collagen fibers (57.28% in Asc and 75.57% in Anonf) and in the LACN, there was more adipose tissue (47.51% in Asc and 58.19% in Anonf) with fewer collagen fibers (34.10% in Asc and 41.76% in Anonf) in interfascicular domains.

CONCLUSIONS

The amount of adipose tissue in LACN non-fascicular area was found to be high at all ages. The presence of less adipose tissue and collagen fibers in the non-fascicular area of the AMACN (below 60 years) could be used for successful nerve grafting when compared to LACN.

Digital nerve reconstruction by multiple Y-shaped nerve grafts at the metacarpophalangeal joint level

Digital nerve injuries are common; injuries of the common digital nerves are less frequent than those involving the proper digital nerves. Traditional techniques used to reconstruct peripheral nerves are: direct suture, autologous nerve grafts, autologous vein grafts, vascularised nerve graft and alloplastic nerve grafts. Autologous nerve grafts remain the most common conduits for segmental defects. Difficulties can arise when attempting to repair complex nerve gaps, particularly when joining the proximal stump of the common digital nerve with two distal stumps of proper digital nerves as in lesions involving the web space. We present below a case of such a lesion. We describe the use of the lateral antebrachial cutaneous nerve (LABCN) as donor nerve, by exploiting its natural branchings.