Neurohistological changes after facial nerve rerouting

Comparative Anatomic Analysis of Neuronavigated Transmastoid-Infralabyrinthine Approaches for Jugular Fossa Pathologies: Short Anterior Rerouting Versus Nonrerouting and Tailored Nonrerouting Techniques

BACKGROUND AND OBJECTIVES

Access to the jugular fossa pathologies (JFPs) via the transmastoid infralabyrinthine approach (TI-A) using the nonrerouting technique (removing the bone anterior and posterior to the facial nerve while leaving the nerve protected within the fallopian canal) or with the short-rerouting technique (rerouting the mastoid segment of the facial nerve anteriorly) has been described in previous studies. The objective of this study is to compare the access to Fisch class C lesions (JFPs extending or destroying the infralabyrinthine and apical compartment of the temporal bone with or without involving the carotid canal) between the nonrerouting and the short-rerouting techniques. Also, some tailored steps to the nonrerouting technique (NR-T) were outlined to enhance access to the jugular fossa (JF) as an alternative to the short-rerouting technique.

METHODS

Neuronavigated TI-A was performed using the nonrerouting, tailored nonrerouting, and short-rerouting techniques on both sides of 10 human head specimens. Exposed area, horizontal distance, surgical freedom, and horizontal angle were calculated using vector coordinates for nonrerouting and short-rerouting techniques.

RESULTS

The short-rerouting technique had significantly higher values than the NR-T ( P < .01) for the exposed area (169.1 ± SD 11.5 mm 2 vs 151.0 ± SD 12.4 mm 2 ), horizontal distance (15.9 ± SD 0.6 mm vs 10.6 ± SD 0.5 mm 2 ), surgical freedom (19 650.2 ± SD 722.5 mm 2 vs 17 233.8 ± SD 631.7 mm 2 ), and horizontal angle (75.2 ± SD 5.1° vs 61.7 ± SD 4.6°). However, adding some tailored steps to the NR-T permitted comparable access to the JF.

CONCLUSION

Neuronavigated TI-A with the short-rerouting technique permits wider access to the JF compared with the NR-T. However, the tailored NR-T provides comparable access to the JF and may be a better option for class C1 and selected class C2 and C3 JFPs.

Facial nerve management in jugular paraganglioma surgery: a literature review

Objective:

This literature review analysed facial nerve management strategies in jugular paraganglioma surgery and discusses the tumour resection rate and the facial nerve outcome associated with each technique.

Methods:

A retrospective review of PubMed and Medline articles on the surgical treatments for jugular paraganglioma was performed. Tumour resection rates and post-operative facial nerve function after non-rerouting, short anterior rerouting and long anterior rerouting approaches were evaluated for each article.

Results:

A total of 15 studies involving a total of 688 patients were included. Post-operative facial nerve function was similar after non-rerouting and short anterior rerouting approaches (p= 0.169); however, both of these techniques had significantly better post-operative facial nerve outcomes compared with long anterior rerouting (p< 0.001 andp= 0.001, respectively). The total tumour removal rate was significantly higher for long anterior rerouting than with the non-rerouting approach (p= 0.016). There was no difference in total tumour removal rate between the long and short anterior rerouting approaches (p= 0.067) and between the short anterior rerouting and non-rerouting approaches (p= 0.867).

Conclusion:

No strict guidelines for facial nerve management in jugular paraganglioma resection are available. Although long anterior rerouting provides the best tumour exposure along with a low morbidity rate, case-by-case selection of the surgical approach is recommended.

Nerve repair: toward a sutureless approach

Peripheral nerve repair for complete section injuries employ reconstructive techniques that invariably require sutures in their application. Sutures are unable to seal the nerve, thus incapable of preventing leakage of important intraneural fluids from the regenerating nerve. Furthermore, sutures are technically demanding to apply for direct repairs and often induce detrimental scarring that impedes healing and functional recovery. To overcome these limitations, biocompatible and biodegradable glues have been used to seal and repair peripheral nerves. Although creating a sufficient seal, they can lack flexibility and present infection risks or cytotoxicity. Other adhesive biomaterials have recently emerged into practice that are usually based on proteins such as albumin and collagen or polysaccharides like chitosan. These adhesives form their union to nerve tissue by either photothermal (tissue welding) or photochemical (tissue bonding) activation with laser light. These biomaterial adhesives offer significant advantages over sutures, such as their capacity to unite and seal the epineurium, ease of application, reduced invasiveness and add the potential for drug delivery in situ to facilitate regeneration. This paper reviews a number of different peripheral nerve repair (or reconstructive) techniques currently used clinically and in experimental procedures for nerve injuries with or without tissue deficit.

Results of anterior facial nerve rerouting procedures for removing skull base tumors

OBJECTIVES

The purpose of this study was to estimate the rates of functional recovery of the facial nerve and of total tumor resection in patients who undergo short anterior rerouting and long anterior rerouting of the facial nerve in removal of skull base tumors.

METHODS

We retrospectively collected data on 37 patients with skull base tumors who underwent facial nerve rerouting during the procedure for tumor removal. Information on the rerouting technique, the completeness of tumor resection, and changes in facial nerve function were obtained from the medical records. Rerouting techniques were classified as short anterior rerouting or long anterior rerouting.

RESULTS

Ten of 16 patients (62.5%) in the group with short anterior rerouting showed postoperative facial palsy, and all completely recovered within 1 year. In the group with long anterior rerouting, 18 of 21 patients (85.7%) showed postoperative facial palsy, and recovery to a preoperative level of facial function was found in 10 patients at 1 year of follow-up. Total tumor resection was possible in 94% and 81% of patients with short rerouting and long rerouting, respectively. The mean operation time was not significantly related to the postoperative recovery of facial function.

CONCLUSIONS

Short rerouting techniques, when appropriately chosen on the basis of tumor and patient characteristics, offer excellent preservation of facial function and tumor resection, comparable to those of long rerouting techniques.