Background & Aims

A variety of biomarkers other than degree of neurovascular compression [1-5] (e.g., ox/carbamazepine responsiveness, type of TN) [6,7] have been used to estimate the likelihood of long-term pain-freedom after MVD. In this study we report the prognostic implications of microstructural changes found in idiopathic trigeminal neuralgia patients with neurovascular contact involving an arterial contact without morphological changes.

Methods

Patients aged 18 years or older who underwent microvascular decompression (MVD) as their initial surgical procedure for iTN with arterial contact without morphological changes between March 2013 and December 2021 were analyzed. Mean diffusivity, radial diffusivity, axial diffusivity, and fractional anisotropy (i.e., MD, RD, AD, FA) were extracted from the cisternal segment of the trigeminal nerve immediately adjacent to the root entry point (REP). We compared the symptomatic and asymptomatic side and the symptomatic side in responders vs. non-responders to MVD.

Results

The MD was significantly increased in the symptomatic trigeminal nerve (1.9 x 10-3 mm2/s ± 5.5 x 10-5 mm2/s) when compared to the asymptomatic trigeminal nerve (1.6 x 10-3 mm2/s ± 6.5 x 10-5 mm2/s, q = 0.00047). The RD was significantly increased in the symptomatic trigeminal nerve (1.6 x 10-3 mm2/s ± 9.8 x 10-5 mm2/s) when compared to the asymptomatic trigeminal nerve (1.2 x 10-3 mm2/s ± 8.3 x 10-5 mm2/s, q = 0.0000066). The FA was significantly decreased in the symptomatic trigeminal nerve (0.37 ± 0.013) when compared to the asymptomatic trigeminal nerve (0.45 ± 0.015, q = 0.0000054). FA was significantly decreased in treatment non-responders (0.33 ± 0.012) when compared to treatment responders (0.38 ± 0.016, q = 0.0056).

Conclusions

FA has potential to pre-operatively identify iTN patients with arterial contact without morphological changes that will respond to MVD. This study identifies a subset of iTN patients who are not truly idiopathic.

References

1. Leal PR, Barbier C, Hermier M, Souza MA, Cristino-Filho G, Sindou M. Atrophic changes in the trigeminal nerves of patients with trigeminal neuralgia due to neurovascular compression and their association with the severity of compression and clinical outcomes. J Neurosurg. 2014;120(6):1484-1495.

2. Hughes MA, Jani RH, Fakhran S, et al. Significance of degree of neurovascular compression in surgery for trigeminal neuralgia. J Neurosurg. 2019:1-6.

3. Duan Y, Sweet J, Munyon C, Miller J. Degree of distal trigeminal nerve atrophy predicts outcome after microvascular decompression for Type 1a trigeminal neuralgia. J Neurosurg. 2015;123(6):1512-1518.

4. Maarbjerg S, Wolfram F, Gozalov A, Olesen J, Bendtsen L. Significance of neurovascular contact in classical trigeminal neuralgia. Brain. 2015;138(Pt 2):311-319.

5. Andersen ASS, Heinskou TB, Rochat P, et al. Microvascular decompression in trigeminal neuralgia – a prospective study of 115 patients. J Headache Pain. 2022;23(1):145.

6. Panczykowski DM, Jani RH, Hughes MA, Sekula RF. Development and Evaluation of a Preoperative Trigeminal Neuralgia Scoring System to Predict Long-Term Outcome Following Microvascular Decompression. Neurosurgery. 2020;87(1):71-79.

Presenting Author

Margaret Tugend

Poster Authors

Margaret Tugend

BA

Columbia University

Lead Author

Katie Traylor

DO

Lead Author

Raviteja Bethamcharla

BS

Lead Author

Yue-Fang Chang

PhD

Lead Author

Stine Maarbjerg

PhD

Department of Neurology, Danish Headache Center, Copenhagen University Hospital - Rigshospitalet

Lead Author

Topics

  • Specific Pain Conditions/Pain in Specific Populations: Neuropathic Pain - Peripheral