Degree of distal trigeminal nerve atrophy predicts outcome after microvascular decompression for Type 1a trigeminal neuralgia

OBJECT: Trigeminal neuralgia is often associated with nerve atrophy, in addition to vascular compression. The authors evaluated whether cross-sectional areas of different portions of the trigeminal nerve on preoperative imaging could be used to predict outcome after microvascular decompression (MVD).

METHODS: A total of 26 consecutive patients with unilateral Type 1a trigeminal neuralgia underwent high-resolution fast-field echo MRI of the cerebellopontine angle followed by MVD. Preoperative images were reconstructed and reviewed by 2 examiners blinded to the side of symptoms and clinical outcome. For each nerve, a computerized automatic segmentation algorithm was used to calculate the coronal cross-sectional area at the proximal nerve near the root entry zone and the distal nerve at the exit from the porus trigeminus. Findings were correlated with outcome at 12 months.

RESULTS: After MVD, 17 patients were pain free and not taking medications compared with 9 with residual pain. Across all cases, the coronal cross-sectional area of the symptomatic trigeminal nerve was significantly smaller than the asymptomatic side in the proximal part of the nerve, which was correlated with degree of compression at surgery. Atrophy of the distal trigeminal nerve was more pronounced in patients who had residual pain than in those with excellent outcome. Among the 7 patients who had greater than 20% loss of nerve volume in the distal nerve, only 2 were pain free and not taking medications at long-term follow-up.

CONCLUSIONS: Trigeminal neuralgia is associated with atrophy of the root entry zone of the affected nerve compared with the asymptomatic side, but volume loss in different segments of the nerve has very different prognostic implications. Proximal atrophy is associated with vascular compression and correlates with improved outcome following MVD. However, distal atrophy is associated with a significantly worse outcome after MVD.

Medienart:

E-Artikel

Erscheinungsjahr:

2015

Erschienen:

2015

Enthalten in:

Zur Gesamtaufnahme - volume:123

Enthalten in:

Journal of neurosurgery - 123(2015), 6 vom: 18. Dez., Seite 1512-8

Sprache:

Englisch

Beteiligte Personen:

Duan, Yifei [VerfasserIn]
Sweet, Jennifer [VerfasserIn]
Munyon, Charles [VerfasserIn]
Miller, Jonathan [VerfasserIn]

Links:

Volltext

Themen:

Case Reports
Journal Article
MVD = microvascular decompression
Microvascular decompression
NVC = neurovascular conflict
Nerve atrophy
Pain
TN = trigeminal neuralgia
Trigeminal neuralgia

Anmerkungen:

Date Completed 28.03.2016

Date Revised 01.12.2015

published: Print-Electronic

Citation Status MEDLINE

doi:

10.3171/2014.12.JNS142086

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM250990970