Neurovascular compression is generally accepted as a valid patho-physiological mechanism of trigeminal neuralgia. Controversies have been known whether this conflict refers to neuro-vascular contact at the root entry zone (1). Most of the published articles point out that there is demyelinisation over the intracranial portion of the trigeminal nerve at the point of conflict or somewhere at the trigeminal nucleus in the pons as in case of multiple sclerosis or ischemia (2,3).
The strongest hypothesis is that a mixed central-peripheral mechanism is present, in which abnormal impulses arise from axons with a damaged myeline sheet, because of different pathologies, from vascular to mechanical compression or to a weak structure of the myelin itself as in demyelinating diseases. (4)
Recently the visualization of neurovascular conflict has been reported to be more probable with 3tesla magnetic resonance imaging (5). But few institutions have the possibility of such expensive studies.
Micro-vascular decompression of the trigeminal nerve through retromastoid approach is considered the most effective and less complicated method compared to glycerol, balloon compression, radiofrequency of Gasser ganglion or gamma knife (5).
In recent articles (5,6) trigeminal nerve root entry zone exploration in cases of TN in lack of clear neurovascular conflict in imaging studies has been reported as beneficial for the pain relief.
Probably the adjacent arachnoid web and intracranial trigeminal nerve modify their relation with sagging effect of ageing predisposing to arachnoid fiber compression over the nerve.
However, I believe that the radiological evidence of a neuro-vascular conflict in case of legal dispute in case of unsuccessful microsurgical exploration could be a saving grace for the neurosurgeon.
References
1. Adams CB: Microvascular compression: an alternative view and hypothesis. J Neurosurg 70:1-12, 1989.
2. Brisman R. Treatment of Trigeminal Neuralgia Associated with Multiple Sclerosis. World Neurosurg. 2013 Oct 10. pii: S1878-8750(13)01304-1. doi:10.1016/j.wneu.2013.10.018.
3. Balestrino M, Leandri M: Trigeminal neuralgia in pontine ischaemia. J Neurol Neurosurg Psychiatry 62:297-298, 1997.
4. Broggi G. Trigeminal neuralgia without evidence of neurovascular conflict: microvascular compression or route entry zone exploration? World Neurosurg. 2013 Sep-Oct;80(3-4):300-1. doi: 10.1016/j.wneu.2012.10.042. Epub 2012 Oct 24.
5. Zhou Q, Liu ZL, Qu CC, Ni SL, Xue F, Zeng QS. Preoperative demonstration of neurovascular relationship in trigeminal neuralgia by using 3D FIESTA sequence. Magn Reson Imaging. 2012 Jun;30(5):666-71. doi: 10.1016/j.mri.2011.12.022. Epub 2012 Mar 9.
6. Revuelta-Gutierrez R, Martinez-Anda JJ, Coll JB, Campos-Romo A, Perez-Peña N. Efficacy and safety of root compression of trigeminal nerve for trigeminal neuralgia without evidence of vascular compression.
World Neurosurg. 2013 Sep-Oct;80(3-4):385-9. doi: 10.1016/j.wneu.2012.07.030. Epub 2012 Aug 10.
Competing interests:
No competing interests
25 March 2014
Ridvan Alimehmeti
Neurosurgeon
Service of Neurosurgery, University Hospital Center "Mother Theresa"
Rapid Response:
Re: Trigeminal neuralgia
Neurovascular compression is generally accepted as a valid patho-physiological mechanism of trigeminal neuralgia. Controversies have been known whether this conflict refers to neuro-vascular contact at the root entry zone (1). Most of the published articles point out that there is demyelinisation over the intracranial portion of the trigeminal nerve at the point of conflict or somewhere at the trigeminal nucleus in the pons as in case of multiple sclerosis or ischemia (2,3).
The strongest hypothesis is that a mixed central-peripheral mechanism is present, in which abnormal impulses arise from axons with a damaged myeline sheet, because of different pathologies, from vascular to mechanical compression or to a weak structure of the myelin itself as in demyelinating diseases. (4)
Recently the visualization of neurovascular conflict has been reported to be more probable with 3tesla magnetic resonance imaging (5). But few institutions have the possibility of such expensive studies.
Micro-vascular decompression of the trigeminal nerve through retromastoid approach is considered the most effective and less complicated method compared to glycerol, balloon compression, radiofrequency of Gasser ganglion or gamma knife (5).
In recent articles (5,6) trigeminal nerve root entry zone exploration in cases of TN in lack of clear neurovascular conflict in imaging studies has been reported as beneficial for the pain relief.
Probably the adjacent arachnoid web and intracranial trigeminal nerve modify their relation with sagging effect of ageing predisposing to arachnoid fiber compression over the nerve.
However, I believe that the radiological evidence of a neuro-vascular conflict in case of legal dispute in case of unsuccessful microsurgical exploration could be a saving grace for the neurosurgeon.
References
1. Adams CB: Microvascular compression: an alternative view and hypothesis. J Neurosurg 70:1-12, 1989.
2. Brisman R. Treatment of Trigeminal Neuralgia Associated with Multiple Sclerosis. World Neurosurg. 2013 Oct 10. pii: S1878-8750(13)01304-1. doi:10.1016/j.wneu.2013.10.018.
3. Balestrino M, Leandri M: Trigeminal neuralgia in pontine ischaemia. J Neurol Neurosurg Psychiatry 62:297-298, 1997.
4. Broggi G. Trigeminal neuralgia without evidence of neurovascular conflict: microvascular compression or route entry zone exploration? World Neurosurg. 2013 Sep-Oct;80(3-4):300-1. doi: 10.1016/j.wneu.2012.10.042. Epub 2012 Oct 24.
5. Zhou Q, Liu ZL, Qu CC, Ni SL, Xue F, Zeng QS. Preoperative demonstration of neurovascular relationship in trigeminal neuralgia by using 3D FIESTA sequence. Magn Reson Imaging. 2012 Jun;30(5):666-71. doi: 10.1016/j.mri.2011.12.022. Epub 2012 Mar 9.
6. Revuelta-Gutierrez R, Martinez-Anda JJ, Coll JB, Campos-Romo A, Perez-Peña N. Efficacy and safety of root compression of trigeminal nerve for trigeminal neuralgia without evidence of vascular compression.
World Neurosurg. 2013 Sep-Oct;80(3-4):385-9. doi: 10.1016/j.wneu.2012.07.030. Epub 2012 Aug 10.
Competing interests: No competing interests