Arterial cross compression of the trigeminal nerve at the pons in trigeminal neuralgia. Case report with autopsy findings

Is percutaneous balloon compression better than microvascular decompression to treat trigeminal neuralgia? A systematic review and meta-analysis

BACKGROUND

Trigeminal neuralgia (TN) is a neuropathic pain that affects one or more branches of the trigeminal nerve. Surgical options after pharmacological failure are Microvascular Decompression (MVD) or percutaneous procedures, which include Balloon Compression (PBC). This study aims to describe pain outcomes and complications after PBC and MVD procedures for patients with trigeminal neuralgia.

METHODS

We performed a systematic review and meta-analysis on PubMed, EMBASE, LILACS, and Web of Science databases up to April 2022, following PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and meta-Analysis). Articles that separately describe pain outcome for MVD and PBC were included. MINORS tool was used for bias assessment. Meta-analysis results are presented in forest plot and funnel plot.

RESULTS

853 studies were assessed for screening, and 11 studies met the inclusion criteria for this review. A total of 1046 patients underwent PBC and 1324 underwent MVD. The subgroup analysis for patients without multiple sclerosis shows that MVD was associated with lower number of patients with pain than PBC, with an OR value of 0.54 (95 % CI 0.34-0.84). All other analyses evidenced a tendency for better outcomes after the MVD procedure, but with no statistically significant difference.

CONCLUSION

Considering short and long pain relief, recurrence of pain and total complications for MVD and PBC, our study found that MVD is the best surgical option available for trigeminal neuralgia.

Three Cases of Trigeminal Neuralgia with Radiographic Absence of Meckel's Cave

Trigeminal neuralgia (TN) is a debilitating but treatable disease. Classic TN has referable vascular compression of the trigeminal nerve, but rarely secondary sources of anatomic compression will present, including vascular malformations, aneurysms, or tumors. Understanding the etiology of the patients' symptoms leads to targeted treatment. Three patients presented with symptoms consistent with TN: shooting, paroxysmal pains in the distribution of the trigeminal nerve. However, imaging revealed no vascular conflict at the root entry zone of the trigeminal nerve. Instead, on the affected side Meckel's cave was absent. No other compressive mass lesion was identified. In all three cases, patients were offered both Gamma Knife Radiosurgery and surgical decompression of Meckel's cave. All 3 patients elected to proceed with stereotactic radiation and reported improvement in pain. Many cases of classic TN can be explained by neurovascular conflict at the trigeminal root entry zone, but secondary sources of compression or restriction along the nerve can result in similar symptomology. In this case series, an absent or hypoplastic ipsilateral Meckel's cave may have produced symptoms consistent with TN. Imaging with fine cuts through Meckel's cave is an important diagnostic tool.

Cerebellopontine angle epidermoid tumor presenting with 'tic convulsif' and tinnitus--case report

A 22-year-old female presented with a cerebellopontine angle epidermoid tumor manifesting as a rare combination of hemifacial spasm, trigeminal neuralgia, and tinnitus. Magnetic resonance imaging demonstrated the tumor distorting the brainstem and the fourth ventricle. The tumor was almost completely resected and the seventh-eighth cranial nerve complex was decompressed by mobilizing the anterior inferior cerebellar artery loop. No arterial loop was related to the trigeminal nerve. The patient was completely relieved of the "tic convulsif" and tinnitus after the surgery. The inflammatory nature of epidermoid tumor may be involved in the etiology of the syndrome. Microvascular decompression may be needed in addition to tumor removal in such cases.

The blood supply of the trigeminal nerve root, with special reference to the trigeminocerebellar artery

The vasculature of the 29 roots of the trigeminal nerve was examined after india ink and gelatin had been injected into the vertebrobasilar arterial system. The trigeminal arteries were most often noted to arise from the superolateral pontine branch of the basilar artery (89.66%), and from the peduncular cerebellar branch of the anterior inferior cerebellar artery (75.86%). The trigeminocerebellar artery supplied two roots (6.89%) of the trigeminal nerves. The number of trigeminal arteries ranged from two to six, and their diameters ranged from 100 to 510 microns. Anastomoses among them were seen in 37.93% of the cases. The arteries formed the vascular rings around 58.61% of the roots. The motor portion of the trigeminal nerve most often received blood from the superolateral pontine artery (79.31%). The same artery most commonly supplied the rostral part of the sensory portion, which corresponded to the ophthalmic division of the trigeminal nerve. The superolateral artery, together with the inferolateral pontine artery and the peduncular cerebellar branch of the anterior inferior cerebellar artery, irrigated the middle part of the sensory portion, which corresponded to the maxillary division. The caudal part of that portion, which corresponded to the mandibular division, was commonly perfused by the peduncular cerebellar branch of the anterior inferior cerebellar artery. In this article, we discuss the possible clinical significance of the anatomic data observed.

Evoked taste thresholds in a normal population and the application of electrogustometry to trigeminal nerve disease

No standardised method for taste threshold measurement is available and therefore comparison between clinical studies is difficult. An electrogustometer was evaluated in normal subjects. No sex difference in taste threshold was noted; however, there was a significant elevation in detection threshold with age and smoking. Electrogustometric values both in patients before and after surgery for trigeminal neuralgia and in patients with trigeminal sensory neuropathy were determined. Many patients with trigeminal nerve disorders had abnormal electrogustometric detection thresholds suggesting that there is possibly an accessory taste pathway through the trigeminal nerve, although in some individuals the site of lesion may be in the brain stem. Electrogustometry is a convenient method for clinically assessing taste.

Clip-grafts in microvascular decompression of the posterior fossa. Technical note

A method is described for the protection of the trigeminal root from recurrent vascular irritation or compression after posterior fossa microvascular decompression. A vascular clip-graft, using a Sundt clip of suitable size, is applied to the sensory root of the trigeminal nerve. The technique has proven safe and effective in a series of nine patients followed for up to 28 months.

Basilar artery ectasia: an unusual cause of trigeminal neuralgia

Basilar artery ectasia may be associated with trigeminal neuralgia as a consequence of trigeminal nerve compression by the aberrant artery. The case histories are presented of four patients, investigation of whom demonstrated the presence of an ectatic basilar artery thought to be the cause of facial pain. The value of intravenous digital subtraction angiography in the investigation of this condition is emphasised. The surgical management is discussed with particular reference to the choice between percutaneous thermocoagulation and posterior fossa microvascular decompression.

Trigeminal neuralgia and hemifacial spasm: treatment by microvascular decompression

On the basis of observation of 26 patients, we consider that the common cause in trigeminal neuralgia and hemifacial spasm is compression of the nerve-root entry zone at the brainstem by a blood vessel, usually an artery. By mobilising the vessel, and securing it away from the nerve, symptoms were relieved in 16 of 17 patients with trigeminal neuralgia and in seven of nine patients with hemifacial spasm for a follow-up period of up to four years. Trigeminal microvascular decompression had few complications, but three patients treated for facial hemispasm had postoperative deafness and one had a probable small brainstem infarct. The major advantage of this surgical approach is that is possible to relieve the symptoms without facial anaesthesia or paralysis.

Abnormal impulse generation in focally demyelinated trigeminal roots

In 12 cats and two Macaca mulatta monkeys, areas of chronic focal injury were induced in the trigeminal root by implantation of a chromic suture in the nerve near its entry into the brain stem. Experimental lesions were examined histologically and electrophysiologically at 1 week, 3 weeks, and 6 weeks after surgery. At 3 weeks following implantation, lesioned nerves showed areas of focal inflammation surrounding implanted sutures with prominent demyelination of adjacent axons. A total of 497 trigeminal units were studied, 304 of which had associated demyelination of the root. In these 304 cells, two types of abnormal impulse generation from areas of focal demyelination were recorded. Reflected orthodromic action potentials and prolonged high-frequency after-discharges following short priming trains of orthodromic stimuli were observed in 23% and 4% of cells, respectively. Ectopic spike initiation from areas of focal demyelination was not dependent upon anatomical continuity of the nerve with the brain stem, was augmented by hyperventilation, and could be eliminated by the intravenous administration of diphenylhydantoin sodium. The relevance of these findings to the pathophysiological mechanisms of pain syndromes involving peripheral nerves in general and the trigeminal system in particular is discussed.

Neurovascular compression in cranial nerve and systemic disease

As we age, our arteries elongate and our brains "sag." As a consequence of these processes, redundant arterial loops and bridging or intrinsic hindbrain veins may cause cross-compression of cranial nerve root entry zones in the cerebellopontine angle. This pulsatile compression can be seen to produce hyperactive dysfunction of the cranial nerve. Symptoms of trigeminal or glossopharyngeal neuralgia (somatic sensory), hemifacial spasm (somatic motor), tinnitus and vertigo (special sensory) and some cases of "essential" hypertension are caused by these vessels compressing cranial nerves V, IX--X, VII, VIII, and left X and medulla oblongata. Using microsurgical techniques, the symptoms may be relieved by vascular decompression, findings and results in 695 paients are briefly reviewed and correlated. A chronic primate model of "essential" hypertension is briefly described.

Microvascular relations of the trigeminal nerve. An anatomical study with clinical correlation

The vascular relationships of the trigeminal nerve root entry zone were examined bilaterally in 20 cadavers of individuals known to be free of facial pain. Fourteen of 40 nerves made contact with an artery, but only four of these showed evidence of compression or distortion of the nerve. In addition, the vascular relationships of 40 trigeminal nerves exposed surgically for treatment of trigeminal neuralgia were studied, and 31 nerves showed compression by adjacent arteries. Venous compression was seen in four of the cadaver nerves and in eight nerves from patients with trigeminal neuralgia. These data support the hypothesis that arterial compression of the trigeminal nerve is associated with trigeminal neuralgia.

Trigeminal neuralgia. Surgical treatment by microvascular decompression of the trigeminal nerve root

The surgical management of trigeminal neuralgia has always been less than ideal. Evidence accumulated over the last 10 years suggests that the condition is caused by vascular compression of the trigeminal nerve root at the brain stem. Removal of this compression by means of micro-neurosurgical techniques has so far been very effective in relieving the pain of trigeminal neuralgia while maintaining normal facial sensation. A series of 10 patients who underwent this procedure is presented. All patients lost their pain, and during the follow-up period of six to 18 months, there have been no recurrences. This experience further demonstrates that the microvascular decompression is a very useful procedure in selected patients.