Comparisons of steroid, acyclovir, lipoprostoglandin E1 and steroid + acyclovir treatments in facial paralysis: a rat study

Delayed facial palsy after microvascular decompression for hemifacial spasm: friend or foe?

OBJECTIVE

The authors investigated the incidence, clinical course, and predisposing factors associated with delayed facial palsy (DFP) following microvascular decompression (MVD).

METHODS

The authors reviewed the records of 310 patients (311 cases) who were followed after MVD for hemifacial spasm (HFS). Of these patients, 45 (14.5%) developed DFP after MVD. The clinical characteristics and predisposing factors of the patients with HFS were investigated to identify prognostic factors that predicted the development of DFP after MVD. Log-rank tests were used to compare times to symptom disappearance, and a logistic regression analysis was performed to compare clinical characteristics between patients who developed DFP and those who did not.

RESULTS

HFS was completely resolved immediately after MVD in 158 cases (50.8%), and HFS eventually disappeared in 289 (92.9%) of the cases. Of the 45 patients with DFP, 17 were men and 28 were women. DFP occurred between postoperative Days 1 and 44 (mean 9.67 days). Finally, 44 patients (97.8%) completely recovered. The average time to recovery was 3.9 months (range 1–24 months). Patients who had experienced an immediate disappearance of HFS experienced a significantly higher occurrence of DFP than those who did not (odds ratio 0.383, 95% confidence interval 0.183–0.802; p = 0.011). In addition, preoperative botulinum neurotoxin injections negatively influenced the occurrence of DFP (p = 0.016).

CONCLUSIONS

In this study, the incidence rate of DFP was slightly higher than previously reported values. Moreover, DFP can occur even when spasms disappear immediately after MVD, but the patients with DFP can fully recover within weeks.

Facial paralysis induced by ear inoculation of herpes simplex virus in rat

OBJECTIVE

Bell's palsy is caused by the reactivation of herpes simplex virus type 1 (HSV-1). Using Balb/c mice inoculated with the KOS strain of HSV-1, we previously developed an animal disease model that simulated mild Bell's palsy. The current study developed an animal disease model of more severe facial palsy than that seen in the mouse model.

METHODS

Three-week-old female Wister rats weighing 60-80g were inoculated on the auricle with HSV-1 and acyclovir was administered intraperitoneally to deactivate the infected HSV-1. Instead of HSV-1, phosphate-buffered saline was used for inoculation as a negative control. Quantitative polymerase chain reaction (PCR), behavior testing (blink reflex), electroneuronography, histopathology of the peripheral nerve, and immunohistochemistry of the facial nerve nucleus were evaluated.

RESULTS

Facial palsy occurred 3-5 days after virus inoculation, and the severity of the facial palsy progressed for up to 7 days. Quantitative PCR showed an increase in HSV-1 DNA copies in the facial nerve from 24 to 72h, suggesting that HSV-1 infection occurred in the nerve. Electroneuronography values were 33.0±15.3% and 110.0±18.0% in HSV-1-inoculated and control rats, respectively. The histopathology of the peripheral nerve showed demyelination and loss of the facial nerve, and the facial nerve nucleus showed degeneration.

CONCLUSION

Facial palsy developed in Wister rats following inoculation of the KOS strain of HSV-1 onto the auricles. The behavioral, histopathological, and electroneuronography data suggested that the severity of facial palsy was greater in our rats than in animals in the previous mouse disease model.

Single dose intravenous methyl prednisolone versus oral prednisolone in Bell's palsy: a randomized controlled trial

Objectives:

Corticosteroids have been used in the treatment of Bell's palsy and several other postinfectious neurological conditions. We hypothesized that administration of a single dose of intravenous (IV) methylprednisolone might be an effective alternative to oral prednisolone.

Materials and Methods:

In this open label, randomized trial, patients with acute Bell's palsy were randomized into two groups. One group received single dose (500 mg) of IV methylprednisolone while the other group received 10 days of oral prednisone. Outcome was assessed at 1 and 3 months with House–Brackmann scale.

Results:

At 3 months, 93 (79.48%) patients had completely recovered. IV methylprednisolone and oral prednisolone groups had similar recovery rates (80% vs. 78.33%, P > 0.05). Patients with Grade 2 and 3 recovered completely. In patients with Grade 6, the recovery rate was 20%. A better outcome was observed if corticosteroids were administered within 3 days of onset of palsy.

Conclusion:

Intravenous methylprednisolone and oral prednisolone showed equivalent benefit in patients with acute Bell's palsy.

Transient delayed facial nerve palsy after inferior alveolar nerve block anesthesia

Facial nerve palsy, as a complication of an inferior alveolar nerve block anesthesia, is a rarely reported incident. Based on the time elapsed, from the moment of the injection to the onset of the symptoms, the paralysis could be either immediate or delayed. The purpose of this article is to report a case of delayed facial palsy as a result of inferior alveolar nerve block, which occurred 24 hours after the anesthetic administration and subsided in about 8 weeks. The pathogenesis, treatment, and results of an 8-week follow-up for a 20-year-old patient referred to a private maxillofacial clinic are presented and discussed. The patient's previous medical history was unremarkable. On clinical examination the patient exhibited generalized weakness of the left side of her face with a flat and expressionless appearance, and she was unable to close her left eye. One day before the onset of the symptoms, the patient had visited her dentist for a routine restorative procedure on the lower left first molar and an inferior alveolar block anesthesia was administered. The patient's medical history, clinical appearance, and complete examinations led to the diagnosis of delayed facial nerve palsy. Although neurologic occurrences are rare, dentists should keep in mind that certain dental procedures, such as inferior alveolar block anesthesia, could initiate facial nerve palsy. Attention should be paid during the administration of the anesthetic solution.