Prosthetic material degeneration over time as a possible factor in delayed recurrence of hemifacial spasm after successful microvascular decompression

BACKGROUND: The effectiveness of microvascular decompression in treating hemifacial spasm is widely accepted. However, some experience recurrence of hemifacial spasm after successful decompression surgery. Especially, delayed recurrence more than 5 years after surgery is rare and the cause of this phenomenon is unknown. CASE DESCRIPTION: A female underwent microvascular decompression to treat her hemifacial spasm 6 years ago. Six years later, her hemifacial spasm recurred and she underwent a second surgery. The second surgery revealed that the sponge had become fragile, losing the ability to absorb the impact of pulsatile compression of the offending artery on the root exit zone of her facial nerve. CONCLUSION: We report a case in which degeneration of material, a sponge (polyurethane), used in decompression surgery caused delayed recurrence of hemifacial spasm. The selection of appropriate prosthetic materials is essential in such functional surgeries.