Contralateral facial nerve palsy following mandibular second molar removal: is there co-relation or just coincidence?

The synergistic role of viral infection and immune response in the pathogenesis of facial palsy

Facial palsy refers to facial muscle paralysis and is typically brought about by viral infections, such as herpes simplex virus type 1 (HSV-1), herpes zoster virus (VZV), and SARS-CoV-2. While significant progress has been achieved in viral facial palsy pathogenesis, mechanisms of viral infection-immunity synergy are yet to be revealed. The authors of this article made an attempt to fill this gap by critically summarizing how viral infection causes inflammation and damage to the facial nerve through an immune response mechanism in the facial palsy pathogenesis. We also summarize the current treatment modalities and their respective efficacies. The article set the conditions under which viral infections caused by HSV-1, VZV, SARS-CoV-2, HIV, and EBV lead to facial paralysis and how the viruses infect the facial nerve, initiate an immune response, and cause nerve death. The impact involved direct viral invasion of neurons, immune evasion and induction of neuroinflammation. The review also discusses the primary role of T cells, B cells and innate immune cells in inducing or relieving the condition. The study emphasizes the need to understand the synergic effect of viral infection and immuneresponse of facial palsy as the foundation of the creation of more potent therapeutic strategies. The paper provides a detailed overview of complex interaction of immuneresponse and viral infection of facial palsy with significant level of importance regarding future research and clinical application.

Facial palsy after temporal lobectomy for epilepsy: illustrative cases

BACKGROUND

Facial palsy is a rare, unexpected complication of temporal lobectomy (TL) for intractable epilepsy. Even without direct manipulation, the facial nerve fibers may be at risk of injury during supratentorial surgery, including TL.

OBSERVATIONS

The authors presented two cases of facial palsy after unremarkable TL. In the first case, the palsy appeared in a delayed fashion and completely resolved within weeks. In the second case, facial nerve dysfunction was observed immediately after surgery, followed by progressive recovery over 2 years. The second patient had a dehiscence of the roof of the petrous bone overlying the geniculate ganglion, which put the facial nerve at risk of bipolar coagulation thermal injury.

LESSONS

Two major mechanisms could explain the loss of facial nerve function after TL: surgery-related indirect inflammation of the nerve resulting in herpesvirus reactivation and delayed dysfunction (Bell's palsy) or indirect thermal damage to the geniculate ganglion through a dehiscent petrous roof.