Role of Acyclovir in Delayed Facial Palsy after Vestibular Schwannoma Resection: A Systematic Review

Introduction: Delayed facial palsy (DFP) is a dysfunction or deterioration of facial nerve function by at least 2 House-Brackmann (HB) grades after a period of normal facial function following surgery or trauma. It has occasionally been observed in patients after vestibular schwannoma (VS) resection. Some attribute the DFP post-VS resection to the reactivation of dormant herpes simplex virus. The aim of this study is to review the cases of patients diagnosed with DFP post-surgical resection of VS and analyze the effects of acyclovir on DFP progression.

Methods: A systematic search has been conducted using EMBASE, MEDLINE, ScienceDirect, and Google Scholar databases, yielding 700 articles. After following the PRISMA Guideline, five articles were finally included. A descriptive analysis was then implemented.

Results: A total of 128 patients had undergone VS resection and experienced DFP thereafter. The antivirals used varied between Acyclovir (ACV), Valcyclovir (VCV), and Famciclovir. The average preoperative House-Brackman (HB) grade was 1 ± 0. The mean reported HB grade upon onset of DFP was 3.18 ± 1.46. The median duration of antiviral treatment was 8 (0) days. Four studies observed a total recovery from facial palsy after treatment with Acyclovir or Valcyclovir (VCV). The mean reported HB grade after ACV or VCV was 1.05 ± 0.21. The remaining paper described a statistically significant decrease in DFP incidence after preoperative administration of Famciclovir.

Conclusion : HSV may be associated with an increased risk of developing DFP following VS resection. Antivirals have shown some decrease although not prevention of DFP occurrence, even upon preoperative administration. Rendering further prospective investigations is a prerequisite.