Microvascular decompression for trigeminal neuralgia

Microvascular decompression for trigeminal neuralgia


Microvascular decompression is a first-line neurosurgical approach for classical trigeminal neuralgia with neurovascular conflict, but can show clinical relapse despite proper decompression. Second-line destructive techniques like radiofrequency thermocoagulation have become reluctantly used due to their potential for irreversible side effects. Subcutaneous peripheral nerve field stimulation (sPNFS) is a minimally invasive neuromodulatory technique which has been shown to be effective for chronic localised pain conditions.

The most frequently used surgical management of trigeminal neuralgia is Microvascular decompression (MVD), followed closely by stereotactic radiosurgery (SRS). Percutaneous stereotactic rhizotomy (PSR) , despite being the most cost-effective, is by far the least utilized treatment modality 1).

Microvascular decompression (MVD) via lateral suboccipital approach is the standard surgical intervention for trigeminal neuralgia treatment.

Teflon™ and Ivalon® are two materials used in MVD for TN. It is an effective treatment with long-term symptom relief and recurrence rates of 1-5% each year. Ivalon® has been used less than Teflon™ though is associated with similar success rates and similar complication rates 2)

Although microvascular decompression (MVD) is the most effective long-term operative treatment for TN, its use in older patient populations has been debated due to its invasive nature. The symptoms and surgical findings presented in a cohort for young-onset TN are similar to those reported in elderly adults. MVD appears to be a safe and effective treatment for young patients with TN 3).

see Microvascular decompression for trigeminal neuralgia and multiple sclerosis

see Awake Microvascular Decompression for Trigeminal Neuralgia.

see also Endoscope assisted microvascular decompression for trigeminal neuralgia.


Compared with the standard microscope-assisted techniques, the 3D exoscopic endoscope-assisted MVD offers an improved visualisation without compromising the field of view within and outside the surgical field 4).

97 patients with primary trigeminal neuralgia (PTN) underwent fully endoscopic microvascular decompression (MVD) via keyhole approach in Capital Medical University Affiliated Beijing Shijitan Hospital from December 2014 to February 2019 was collected. During fully endoscopic MVD in PTN via keyhole approach, performer use natural clearance without grinding except developed rock bone crest or excessive retraction of the brain tissue, visually and panoramically observe and evaluate the CPA area, accurately identify the responsible vessels, to avoid the omission of responsible vessels or insufficient decompression. And the use of preplaced technology, bridging technology and submersible technology, ensure the efficacy of surgery and reduce the surgical side injuries. Barrow Neurological Institute Pain Intensity Score was used to evaluate the efficacy and identify the recurrence. The surgical efficacy was analyzed. The offending vessels were identified under endoscope in 96 cases. Among them, arterial compression was found in 77 cases, venous compression in 6 cases, and both arterial and venous compression in 13 cases. About the pain outcomes, 87 cases had immediate and complete relief of pain, 5 cases had almost relief of pain, 4 cases had partial relief of pain, and still needed medication control, but the dose was lower than that before operation, and 1 case had no obvious relief of pain. About complications, there were 4 cases of temporary facial numbness, 1 case of temporary hearing loss, both of them recovered after symptomatic treatment. There was no cerebral infarction or hemorrhage, intracranial or incision infection. All cases were followed up for 3.0-38.0 months with a median period of(22.4±2.2) months. During the follow-up periods, postoperative recurrence occurred in 3 cases. Fully endoscopic MVD for PTN through keyhole approach, provides panoramic view to avoid omission of offending vessels and reduce complications, seemed to be a safe and effective surgical method 5).

Using preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, PubMedCochrane Library, and Scopus were queried for primary studies examining pain outcomes after MVD for TN published between 1988 and March 2018. Potential biases were assessed for included studies. Pain freedom (ie, Barrow Neurological Institute score of 1) at last follow-up was the primary outcome measure. Variables associated with pain freedom on preliminary analysis underwent formal meta-analysis. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for possible predictors.

Outcome data were analyzed for 3897 patients from 46 studies (7 prospective, 39 retrospective). Overall, 76.0% of patients achieved pain freedom after MVD with a mean follow-up of 1.7 ± 1.3 (standard deviation) yr. Predictors of pain freedom on meta-analysis using random effects models included (1) disease duration ≤5 yr (OR = 2.06, 95% CI = 1.08-3.95); (2) arterial compression over venous or other (OR = 3.35, 95% CI = 1.91-5.88); (3) superior cerebellar artery involvement (OR = 2.02, 95% CI = 1.02-4.03), and (4) type 1 Burchiel classification (OR = 2.49, 95% CI = 1.32-4.67).

Approximately three-quarters of patients with drug-resistant TN achieve pain freedom after MVD. Shorter disease duration, arterial compression, and type 1 Burchiel classification may predict a more favorable outcome. These results may improve patient selection and provider expectations 6).

Microvascular decompression for trigeminal neuralgia technique.

Microvascular decompression for trigeminal neuralgia outcome.

Microvascular decompression for trigeminal neuralgia complications

Microvascular decompression for trigeminal neuralgia case series.


1)

Sivakanthan S, Van Gompel JJ, Alikhani P, van Loveren H, Chen R, Agazzi S. Surgical management of trigeminal neuralgia: use and cost-effectiveness from an analysis of the medicare claims database. Neurosurgery. 2014 Sep;75(3):220-6. doi: 10.1227/NEU.0000000000000430. PubMed PMID: 24871139.
2)

Pressman E, Jha RT, Zavadskiy G, Kumar JI, van Loveren H, van Gompel JJ, Agazzi S. Teflon™ or Ivalon®: a scoping review of implants used in microvascular decompression for trigeminal neuralgia. Neurosurg Rev. 2019 Nov 30. doi: 10.1007/s10143-019-01187-0. [Epub ahead of print] Review. PubMed PMID: 31786660.
3)

Yu F, Yin J. Young-onset trigeminal neuralgia: a clinical study and literature review. Acta Neurochir (Wien). 2021 Apr 17. doi: 10.1007/s00701-021-04848-6. Epub ahead of print. PMID: 33864143.
4)

Li Ching Ng A, Di Ieva A. How I do it: 3D exoscopic endoscope-assisted microvascular decompression. Acta Neurochir (Wien). 2019 May 29. doi: 10.1007/s00701-019-03954-w. [Epub ahead of print] PubMed PMID: 31144166.
5)

Peng WC, Guan F, Hu ZQ, Huang H, Dai B, Zhu GT, Mao BB, Xiao ZY, Zhang BL, Liang X. [Efficacy analysis of fully endoscopic microvascular decompression in primary trigeminal neuralgia via keyhole approach]. Zhonghua Yi Xue Za Zhi. 2021 Mar 30;101(12):856-860. Chinese. doi: 10.3760/cma.j.cn112137-20200630-02002. PMID: 33789367.
6)

Holste K, Chan AY, Rolston JD, Englot DJ. Pain Outcomes Following Microvascular Decompression for Drug-Resistant Trigeminal Neuralgia: A Systematic Review and Meta-Analysis. Neurosurgery. 2020 Feb 1;86(2):182-190. doi: 10.1093/neuros/nyz075. PubMed PMID: 30892607.

Neuropathic dental pain

Neuropathic dental pain

Dental pain may have another origin than teeth. It may be caused by myofascial, neurovascular, cardiac, neurological, sinusal or psychological factors.

A high percentage of patients that are surgically treated for trigeminal neuralgia consult their dentist first and receive possibly unjustified dental treatment. Differential diagnoses include odontogenic pain syndromes as well as atypical orofacial pain. The present literature acknowledges difficulties in correctly diagnosing trigeminal neuralgia, but seems to underestimate the extent 1).

It is notoriously difficult to treat. To date, there are no deep brain stimulation (DBS) studies on this specific pain condition and no optimal target or “sweet spot” has ever been defined.

To determine the optimal thalamic target for improving this condition by utilizing the steering abilities of a directional DBS electrode (Vercise CartesiaTM Model DB-2202-45, Boston Scientific).

literature search and review of the database identified 3 potential thalamic targets. A directional lead was implanted in a patient with NDP and its current steering used to test the effects in each nucleus. The patient reported her pain after 2 wk of stimulation in a prospective randomized blinded clinical trial of one. Quality of life measurements were performed before and after 3 mo on their best setting.

They identified 3 potential nuclei: the Centromedian nucleus (CM), Ventral posteromedial nucleus (VPM), and Anterior pulvinar nucleus. The best results were during VPM stimulation (>90% reduction in pain) and CM stimulation (50% reduction). Following 3 mo of VPM-DBS in combination of lateral CM stimulation, their pain disability index dropped (from 25 to 0) and short form 36 improved (from 67.5 to 90).

VPM stimulation in combination with CM stimulation is a promising target for NDP. DBS electrode directionality can be used to test multiple targets and select a patient specific “sweet spot” for NDP treatment 2).

Case reports

Imholz et al. discuss 2 rare cases of patients who presented with a cerebellopontine angle tumor, who initially manifested with symptoms of dental pain.

The first patient, male, 44 years of age presented to his dentist with toothache (47), which led to its extraction. Five months later, a second painful episode, more characteristic, revealed the presence of a vestibular schwannoma, which was successfully treated and led to the disappearance of the pain. The second case, a 43-year-old female presented to her dentist with toothache (46), which lead the dentist perform a root filling. Two years later, with a 3rd episode of dental pain, more relevant of a trigeminal nevralgia, a epidermoid cyst of the right cerebellopontine angle was identified and successfully treated leading to the disappearance of the pain.

Cerebellopontine angle tumors of this type may lead, in exceptional cases to symptoms of dental pain. Therefore, in face of atypical tooth or facial pain, both a detailed medical history and a detailed examination are necessary, in order to investigate any neurological signs and symptoms, before undertaking any non-essential dental treatment, which may be detrimental for the patients 3).


1)

von Eckardstein KL, Keil M, Rohde V. Unnecessary dental procedures as a consequence of trigeminal neuralgia. Neurosurg Rev. 2015 Apr;38(2):355-60; discussion 360. doi: 10.1007/s10143-014-0591-1. Epub 2014 Nov 25. PubMed PMID: 25418511.
2)

Krüger MT, Avecillas-Chasin JM, Heran MKS, Naseri Y, Sandhu MK, Polyhronopoulos NE, Sarai N, Honey CR. Directional Deep Brain Stimulation Can Target the Thalamic “Sweet Spot” for Improving Neuropathic Dental Pain. Oper Neurosurg (Hagerstown). 2021 May 6:opab136. doi: 10.1093/ons/opab136. Epub ahead of print. PMID: 33956987.
3)

Imholz B, Lombardi T, Scolozzi P. [Toothache: At what point has a pontocerebellar angle tumor to be evoked?]. Rev Stomatol Chir Maxillofac Chir Orale. 2015 May 19. pii: S2213-6533(15)00068-3. doi: 10.1016/j.revsto.2015.04.002. [Epub ahead of print] French. PubMed PMID: 26001346.

Trigeminal nerve

Trigeminal nerve

Johann Friedrich Meckel made the first description of the subarachnoid space investing the trigeminal nerve into the middle fossa.

Possible pathways for facial pain include: trigeminal nerve (portio major as well as portio minor (motor root).

Supratentorial sensory perception, including facial pain, is subserved by the trigeminal nerve, in particular, by the branches of its ophthalmic nerve, which provide an extensive innervation of the dura mater and of the major brain blood vessels. In addition, contrary to previous assumptions, studies on awake patients during surgery have demonstrated that the mechanical stimulation of the pia mater and small cerebral vessels can also produce pain. The trigeminovascular system, located at the interface between the nervous and vascular systems, is therefore perfectly positioned to detect sensory inputs and influence blood flow regulation. Despite the fact that it remains only partially understood, the trigeminovascular system is most probably involved in several pathologies, including very frequent ones such as migraine, or other severe conditions, such as subarachnoid hemorrhage. The incomplete knowledge about the exact roles of the trigeminal system in headacheblood flow regulationBlood-brain Barrier Permeability, and trigemino-cardiac reflex warrants for an increased investigation of the anatomy and physiology of the trigeminal system 1).

The trigeminal nerve complex is a very important and somewhat unique component of the nervous system. It is responsible for the sensory signals that arise from the most part of the facemouthnosemeninges, and facial muscles, and also for the motor commands carried to the masticatory muscles. These signals travel through a very complex set of structures: dermal receptors, trigeminal branches, Gasserian ganglion, central nuclei, and thalamus, finally reaching the cerebral cortex. Other neural structures participate, directly or indirectly, in the transmission and modulation of the signals, especially the nociceptive ones; these include vagus nervesphenopalatine ganglion, occipital nerves, cervical spinal cord, periaqueductal gray matter, hypothalamus, and motor cortex. But not all stimuli transmitted through the trigeminal system are perceivable. There is a constant selection and modulation of the signals, with either suppression or potentiation of the impulses. As a result, either normal sensory perceptions are elicited or erratic painful sensations are created 2).


Originating in the posterior fossa of the brain stem, it follows a long and complex course towards its distribution territory, crossing several regions with a complex anatomy and establishing important relationships with several structures.

The nerve fibers originate in the brainstem and are part of several grey matter nuclei occupying all the brainstem and even the first spinal cervical segments.

Each of these sensitive and motor nuclei represents different processing centers, and there is a true systematization of the information this nervous tract is responsible for conducting.

The sensitive nucleus is the largest, comprising 3 true sub-nuclei, each responsible for each aspect of the general sensitivity. The highest is the mesencephalic nucleus, located in the tegmentum close to the midline and to the grey matter close to the Sylvian aqueduct. The neurons that form this nucleus are in charge of the propioceptive integration in the Vth nerve territory, high level information for correct mastication. The main nucleus is in the pons, it is also situated in the depth of the tegmentum, and is responsible for the tactile integration of the territory of this nerve. Finally, the inferior nucleus occupies the tegmentum of the medulla, extending caudally to the first segments of the cervical spine, and is in charge of thermal and pain information. Its location explains the possible appearance of symptoms in the facial territory in patients with a degenerative/inflammatory disorder of the upper cervical spine. There is one single motor nucleus, located in the pons tegmentum supplying mastication muscles, and is correspondingly called mastication nucleus. The fibers related with all these nuclei gather in the pons and emerge through the lateral sector of its anterior aspect, forming a thick nervous tract with two roots: a thicker and lateral sensitive root and a thinner more medial motor root.

The only intra-axial segment of the Vth ends there and initiates its long course to its distribution territory; it is formed by different sub-segments before dividing itself into its terminal branches (the cisternal and Gasserian or transdural segments).

The point where the roots emerge in the brainstem is called “REZ” (Root Entry Zone), an anatomical landmark of great functional hierarchy.

see Trigeminal nerve cisternal portion.

The trigeminal nerve as the name indicates is composed of three large branches. They are the ophthalmic nerve (V1, sensory), maxillary nerve (V2, sensory), and mandibular nerve (V3, motor and sensory) branches. The large sensory root and smaller motor root leave the brainstem at the mid-lateral surface of pons.

The trigeminal nerve (the fifth cranial nerve, or simply CN V) is a nerve responsible for sensation in the face and certain motor functions such as biting and chewing. It is the largest of the cranial nerves. Its name (“trigeminal” = tri- or three, and -geminus or twin, or thrice twinned) derives from the fact that each trigeminal nerve, one on each side of the pons, has three major branches: the ophthalmic nerve (V1), the maxillary nerve (V2), and the mandibular nerve (V3). The ophthalmic and maxillary nerves are purely sensory. The mandibular nerve has both cutaneous and motor functions.

Sensory information from the face and body is processed by parallel pathways in the central nervous system. The motor division of the trigeminal nerve is derived from the basal plate of the embryonic pons, while the sensory division originates from the cranial neural crest.

see Trigeminal nerve sensory pathways.

Trigeminal nerve-related pathology.

see Trigeminal nerve imaging.


1)

Terrier LM, Hadjikhani N, Velut S, Magnain C, Amelot A, Bernard F, Zöllei L, Destrieux C. The trigeminal system: The meningovascular complex- A review. J Anat. 2021 Feb 18. doi: 10.1111/joa.13413. Epub ahead of print. PMID: 33604906.
2)

Goellner E, Rocha CE. Anatomy of Trigeminal Neuromodulation Targets: From Periphery to the Brain. Prog Neurol Surg. 2020 Oct 6;35:1-17. doi: 10.1159/000511257. Epub ahead of print. PMID: 33022684.
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