Facial nerve repair: fibrin adhesive coaptation versus epineurial suture repair in a rodent model

Fibrin Glue and Its Alternatives in Peripheral Nerve Repair

Over the past century, many advancements have been made in peripheral nerve repair, yet these reconstructions still remain a challenge. Although sutures have historically been used for neurorrhaphy, they sometimes fail to provide optimal outcomes. As a result, multiple adhesive compounds are currently being investigated for their efficacy in nerve repair. Recently, fibrin glue has shown utility in peripheral nerve repair, and the body of evidence supporting its use continues to grow. Fibrin glue has been shown to reduce inflammation, improve axonal regeneration, and provide excellent functional results. This alternative to traditional suture neurorrhaphy could potentially improve outcomes of peripheral nerve reconstruction.

Comparison between VII-to-VII and XII-to-VII coaptation techniques for early facial nerve reanimation after surgical intra-cranial injuries: a systematic review and pooled analysis of the functional outcomes

The surgical injury of the intracranial portion of the facial nerve (FN) is a severe complication of many skull base procedures, and it represents a relevant issue in terms of patients' discomfort, social interactions, risk for depression, and social costs. The aim of this study was to investigate the surgical and functional outcomes of the most common facial nerve rehabilitation techniques. The present study is a systematic review of the pertinent literature, according to the PRISMA guidelines. Two different online medical databases (PubMed, Scopus) were screened for studies reporting the functional outcome, measured by the House-Brackman (HB) scale, and complications, in FN early reanimation, following surgical injuries on its intracranial portion. Data on the VII-to-VII and XII-to-VII coaptation, the surgical technique, the use of a nerve graft, the duration of the deficit, and complications were collected and pooled. The XII-to-VII end-to-side coaptation seems to provide higher chances for functional restoration (HB 1-3) than the VII-to-VII (68.8% vs 60.6%), regardless of the duration of the palsy deficit, the use or not of a nerve graft, and the use of stitches or glues. However, its complication rate was as high as 28.6%, and a second procedure is then often needed. The XII-to-VII side-to-end coaptation is the most effective in providing a functional outcome (HB 1-3), even though it is associated to a higher complication rate. Further trials are needed to better investigate this relevant topic, in terms of health-related social costs and patients' quality of life.

Animal models used to study direct peripheral nerve repair: a systematic review

Objective:

Peripheral nerve repair is required after traumatic injury. This common condition represents a major public health problem worldwide. Recovery after nerve repair depends on several factors, including the severity of the injury, the nerve involved, and the surgeon’s technical skills. Despite the precise microsurgical repair of nerve lesions, adequate functional recovery is not always achieved and, therefore, the regeneration process and surgical techniques are still being studied. Pre-clinical animal models are essential for this research and, for this reason, the focus of the present systematic review (according to the PRISMA statement) was to analyze the different animal models used in pre-clinical peripheral nerve repair studies.

Data sources:

Original articles, published in English from 2000 to 2018, were collected using the Web of Science, Scopus, and PubMed databases.

Data selection:

Only preclinical trials on direct nerve repair were included in this review. The articles were evaluated by the first two authors, in accordance with predefined data fields.

Outcome measures:

The primary outcomes included functional motor abilities, daily activity and regeneration rate. Secondary outcomes included coaptation technique and animal model.

Results:

This review yielded 267 articles, of which, after completion of the screening, 49 studies were analyzed. There were 1425 animals in those 49 studies, being rats, mice, guinea pigs, rabbits, cats and dogs the different pre-clinical models. The nerves used were classified into three groups: head and neck (11), forelimb (8) and hindlimb (30). The techniques used to perform the coaptation were: microsuture (46), glue (12), laser (8) and mechanical (2). The follow-up examinations were histology (43), electrophysiological analysis (24) and behavioral observation (22).

Conclusion:

The most widely used animal model in the study of peripheral nerve repair is the rat. Other animal models are also used but the cost-benefit of the rat model provides several strengths over the others. Suture techniques are currently the first option for nerve repair, but the use of glues, lasers and bioengineering materials is increasing. Hence, further research in this field is required to improve clinical practice.

Facial Nerve Injury and Repair: A Practical Review for Cutaneous Surgery

BACKGROUND

The facial nerve and its branches are at risk of injury during dermatologic surgery. Few publications in the dermatologic literature discuss facial nerve injury and management.

OBJECTIVE

To review facial nerve injury and management, including static and dynamic repair techniques, and to review outcomes in facial nerve reconstruction.

METHODS

Two detailed literature reviews were performed using PubMed. First, articles reporting facial nerve injury and/or management in the dermatologic literature were identified. In addition, articles pertaining to outcomes in facial nerve reconstruction with a minimum of 20 patients were included.

RESULTS

Fifty-three articles reporting outcomes in facial nerve reconstruction were identified and consist of retrospective reviews and case series. Most patients achieve improvement in facial symmetry and movement with nerve repair.

CONCLUSION

Timing of facial nerve repair is an important consideration in management of facial nerve injury, with earlier repairs achieving better outcomes. Facial nerve repair does not result in normal facial movement, and improvements may require a year or more to be realized. Many options exist for facial nerve reconstruction, and patients with long-standing facial nerve injuries may still benefit from treatment.

Toward the Bionic Face: A Novel Neuroprosthetic Device Paradigm for Facial Reanimation Consisting of Neural Blockade and Functional Electrical Stimulation

BACKGROUND

Facial palsy is a devastating condition potentially amenable to rehabilitation by functional electrical stimulation. Herein, a novel paradigm for unilateral facial reanimation using an implantable neuroprosthetic device is proposed and its feasibility demonstrated in a live rodent model. The paradigm comprises use of healthy-side electromyographic activity as control inputs to a system whose outputs are neural stimuli to effect symmetric facial displacements. The vexing issue of suppressing undesirable activity resulting from aberrant neural regeneration (synkinesis) or nerve transfer procedures is addressed using proximal neural blockade.

METHODS

Epimysial and nerve cuff electrode arrays were implanted in the faces of Wistar rats. Stimuli were delivered to evoke blinks and whisks of various durations and amplitudes. The dynamic relation between electromyographic signals and facial displacements was modeled, and model predictions were compared against measured displacements. Optimal parameters to achieve facial nerve blockade by means of high-frequency alternating current were determined, and the safety of continuous delivery was assessed.

RESULTS

Electrode implantation was well tolerated. Blinks and whisks of tunable amplitudes and durations were evoked by controlled variation of neural stimuli parameters. Facial displacements predicted from electromyographic input modelling matched those observed with a variance-accounted-for exceeding 96 percent. Effective and reversible facial nerve blockade in awake behaving animals was achieved, without detrimental effect noted from long-term continual use.

CONCLUSIONS

Proof-of-principle of rehabilitation of hemifacial palsy by means of a neuroprosthetic device has been demonstrated. The use of proximal neural blockade coupled with distal functional electrical stimulation may have relevance to rehabilitation of other peripheral motor nerve deficits.

Stimulation of morphofunctional repair of the facial nerve with photobiomodulation, using the end-to-side technique or a new heterologous fibrin sealant

This research evaluated the influence of Photobiomodulation Therapy (PBMT) on lesions of the facial nerve repaired with the end-to-side technique or coaptation with a new heterologous fibrin sealant. Thirty-two Wistar rats were separated into 5 groups: Control group (CG), where the buccal branch of the facial nerve was collected; Experimental Suture Group (ESG) and Experimental Fibrin Group (EFG), in which the buccal branch was end-to-side sutured to the zygomatic branch on the right side of the face or coaptated with fibrin sealant on the left side; Experimental Suture Laser Group (ESLG) and Experimental Fibrin Laser Group (EFLG), in which the same procedures were performed as the ESG and EFG, associated with PBMT (wavelength of 830nm, energy density 6.2J/cm², power output 30mW, beam area of 0.116cm², power density 0.26W/cm², total energy per session 2.16J, cumulative dose of 34.56J). The laser was applied for 24s/site at 3 points on the skin's surface, for a total application time of 72s, performed immediately after surgery and 3 times a week for 5weeks. A statistically significant difference was observed in the fiber nerve area between the EFG and EFLG (57.49±3.13 and 62.52±3.56μm², respectively). For the area of the axon, fiber diameter, axon diameter, myelin sheath area and myelin sheath thickness no statistically significant differences were found (p<0.05). The functional recovery of whisker movement occurred faster in the ESLG and EFLG, which were associated with PBMT, with results closer to the CG. Therefore, PBMT accelerated morphological and functional nerve repair in both techniques.

The effects of venous ensheathment on facial nerve repair in the rat

OBJECTIVE

To investigate the protective effect of autologous venous ensheathment on sutured rat facial nerve and to test whether the ensheathment could improve the functional recovery of repaired nerve and accuracy of axonal growth.

STUDY DESIGN

In vivo study.

METHODS

Forty-six rats were examined, with six rats serving as normal controls and 40 receiving facial nerve transection and suture repair (SR) or transection and suture repair with an additional venous ensheathment (VE). The rats were then subjected to functional testing, histological assessment of nerve specimens, or retrograde tracing, respectively.

RESULTS

At the postoperative day (POD) 60, the venous ensheathment showed no adhesion at the surrounding tissues. No significant difference in neuroma formation was found between the two surgical manipulations (SR and VE groups) (P < 0.05). Retrogradely labeled motoneurons in facial nuclei were extremely disorganized after the facial nerve undertook surgical manipulation. In all manipulated groups, double retrogradely labeled neurons, indicative of aberrant axonal branching during regeneration, could be observed after peripheral manipulation across all time points. With the two facial surgical manipulations, the average count of double-labeled neurons at POD 60 was significantly less than at POD 21 (P < 0.05).

CONCLUSION

Autologous venous ensheathment could not help with the functional recovery of facial nerve or improve the accuracy of axonal regeneration. Further studies are warranted to elucidate the effects of venous ensheathment in other motor and sensory nerve models.

LEVEL OF EVIDENCE

NA. Laryngoscope, 127:1558-1564, 2017.

Use of Fibrin Glue as an Adjunct in the Repair of Lingual Nerve Injury: Case Report

This report describes a case of lingual nerve injury repair using a novel technique in which Tisseel fibrin glue was used to stabilize an Axoguard nerve conduit placed around the site of primary neurorrhaphy to decrease the number of sutures required for stabilization. Five months postoperatively, the patient subjectively had increased sensation and improved taste in the left lingual nerve distribution. At neurosensory examination, the patient exhibited functional neurosensory recovery (S3+ on the Medical Research Council Scale).

Fibrin sealants: surgical hemostat, sealant and adhesive

INTRODUCTION

Fibrin sealants (FS) have been approved for use in the United States since 1998. Since approval, they have been used in a wide variety of clinical settings and new products continue to be introduced.

AREAS COVERED

This review covers the literature supporting the USA FDA-approved indications for FS products produced by Baxter Corp. Literature review of PubMed, the Cochrane Library, FDA approval documents and product websites yielded information contained in this article. Mechanism of action, efficacy and safety of these products are covered.

EXPERT OPINION

FS are generally safe, popular and are used for a wide variety of off-label indications. Their use appears to be expanding rapidly. For many uses, including approved ones, large well-controlled trials are still needed. Additionally, cost-effectiveness data for these products would be a great benefit in guiding their future use.