Delayed presentation of traumatic facial nerve (CN VII) paralysis

Experimental research on treatment of injured facial nerves induced by hepatocyte growth factor mediated by ultrasound-targeted microbubble destruction

The purpose of our study was to explore the regeneration effect of the ultrasound (US)-targeted microbubble destruction-mediated eukaryotic coexpression vector (pIRES2-enhanced green fluorescent protein [EGFP]/hepatocyte growth factor [HGF]) with EGFP and HGF gene system on facial nerve injury in rats. Forty rats were randomly divided into 4 groups after the models of facial nerve injury were established: A, phosphate-buffered saline (PBS) group; B, HGF and microbubble (HGF + MB) group; C, HGF and US (HGF + US) group; and D, HGF + US + microbubble (HGF + MB/US) group. Gene and protein levels of HGF were detected by quantitative real-time reverse transcriptase-polymerase chain reaction and Western blot, respectively. The expression of pEGFP in facial nerve trunks was examined by laser scanning confocal microscope; HGF gene and protein expression were significantly higher in D group compared with those of the other groups (P < 0.05). The expression of pEGFP was the strongest in D group (P < 0.05). These data indicate that US-targeted microbubble destruction effectively transfects the HGF gene into target tissues and has a significant effect on an injured facial nerve, thus providing a new strategy for gene therapy in facial nerve injury.

Delayed Facial Palsy After the Anterior Petrosal Approach

OBJECTIVE

In this case report, delayed facial palsy developed in a patient without any direct manipulation of the main part of the facial nerve during an anterior petrosal approach. We discuss putative etiologies and management techniques that may help avoid this problem.

CLINICAL PRESENTATION

A 21-year-old woman underwent anterior petrosectomy for gross total resection of a low-grade chondrosarcoma. Six days later, the patient presented with left-sided facial weakness in the emergency department.

RESULTS

Examination revealed evidence of House-Brackmann grade V/VI left-sided facial palsy, and repeat magnetic resonance imaging revealed diffuse enhancement of the contents of the internal auditory canal that was not present immediately after surgery. After a 10-day course of acyclovir and a tapering dose of methylprednisolone, the facial palsy slowly diminished and resolved 2 months after the onset.

CONCLUSION

This unique development of delayed facial palsy after an isolated anterior petrosal approach is evidence that this complication should be considered when dissecting along the floor of the middle fossa. Exposure of the intracranial or intracanalicular segment of the facial nerve is not necessary for delayed facial palsy to develop. Proposed mechanisms (ie, viral reactivation, vasospasm, neural edema) of this condition remain unproven. Prognosis for recovery has been reported to be excellent, with or without treatment.