Trigeminal nerve atrophy predicts pain recurrence after gamma knife stereotactic radiosurgery for classical trigeminal neuralgia

Yong Sin Hu, Cheng Chia Lee, Wan Yuo Guo, Chung Jung Lin*, Huai Che Yang, Hsiu Mei Wu, Kang Du Liu, Wen Yuh Chung

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

BACKGROUND Trigeminal nerve atrophy and neurovascular compression (NVC) are frequently observed in classical trigeminal neuralgia (CTN). OBJECTIVE To determine whether nerve characteristics contribute to Gamma Knife (Elekta AB, Stockholm, Sweden) surgery (GKS) outcomes in unilateral CTN without previous surgery. METHODS From 2006 to 2012, 67 patients with unilateral CTN without previous surgery received GKS with a maximal dose of 90 Gy delivered to the trigeminal nerve juxta brainstem. Two evaluators, blinded to the side of pain, analyzed the magnetic resonance images before GKS to obtain the parameters, including nerve cross-sectional area (CSA), vessel type of NVC, and site of NVC along the nerve. Correlations of the parameters with pain relief (Barrow Neurological Institute [BNI] grades I-IIIb) and recurrence (BNI grades VI-V) were made by using Cox regression and Kaplan-Meier analyses. RESULTS The median CSA of the symptomatic nerves was significantly smaller than that of the asymptomatic nerves (4.95 vs 5.9 mm 2, P <.001). After adjustment for age and sex, larger nerve CSA was associated with lower initial pain relief (hazard ratio 0.81, P =.03) and lower pain recurrence after initial response (hazard ratio 0.58, P =.02). Patients with nerve atrophy (CSA of ≤ 4.4 mm 2 after receiver operating characteristic curve analysis) had a lower 5-yr probability of maintaining pain relief after initial response than those without nerve atrophy (65% vs 86%, P =.04). CONCLUSION Trigeminal nerve atrophy may predict pain recurrence in patients with initial post-GKS relief of CTN. Arterial and proximal NVC are not predictive of GKS outcomes. Future studies are required to determine optimal treatments for long-term pain relief in patients with CTN and trigeminal nerve atrophy.

Original languageEnglish
Pages (from-to)927-934
Number of pages8
JournalNeurosurgery
Volume84
Issue number4
DOIs
StatePublished - 1 Apr 2019

Keywords

  • Clinical outcome
  • Magnetic resonance imaging
  • Neurovascular compression
  • Pain
  • Stereotactic radiosurgery
  • Trigeminal nerve atrophy
  • Trigeminal neuralgia

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