# Outcomes, Predictors of Retreatment, and Complications After Repeat Gamma Knife Radiosurgery for Trigeminal Neuralgia: A Single-Center Retrospective Cohort Study

## TL;DR

This study examines the effectiveness and risks of repeat Gamma Knife surgery for trigeminal neuralgia, finding it offers moderate pain relief but with a risk of facial numbness.

## Contribution

The study identifies prior microvascular decompression and lower initial radiation dose as key predictors for needing retreatment.

## Key findings

- Facial hypoesthesia was the most common complication after repeat Gamma Knife surgery.
- Prior microvascular decompression and lower initial radiation dose were significant predictors of retreatment.
- Repeat Gamma Knife surgery provided moderate pain relief but limited long-term benefits.

## Abstract

Objective: This study was conducted to evaluate the outcomes of repeat Gamma Knife surgery (GKS) in patients with recurrent trigeminal neuralgia (TN), identify predictors for retreatment, and characterize associated complications.

Methods: Among 198 patients initially treated with GKS for TN, 34 (17.2%) underwent a second procedure due to recurrent or persistent pain. After applying the eligibility criteria, 25 patients were analyzed. Factors associated with retreatment were assessed, and complications and pain relief outcomes following repeat GKS were evaluated.

Results: Prior microvascular decompression (MVD) and lower initial radiation dose were significantly associated with need for retreatment (p < 0.001 and p = 0.014, respectively). Neurovascular conflict and prior rhizotomy were not statistically significant predictors. Facial hypoesthesia was the most common complication after repeat GKS (64%). Repeat treatment yielded moderate pain relief in most patients, but durable long-term benefit was limited, consistent with literature reporting 40-60% efficacy.

Conclusions: Repeat GKS is a valuable option for recurrent TN but presents a risk of sensory complications. Prior MVD and lower initial dose are important predictors of retreatment necessity, guiding individualized patient counseling and treatment planning.