An anatomical study of the neurovascular relationships at the trigeminal root entry zone

We aimed to study the neurovascular relationships at the trigeminal root entry zone in the normal population to help determine the pathogenesis of trigeminal neuralgia. We studied 50 fresh cadavers asymptomatic for trigeminal neuralgia or other facial pain during life and examined the 100 trigeminal root entry zones (REZ) using either a transtentorial (34 cadavers) or an infratentorial approach (16 cadavers). A vascular relationship was seen in 39 REZ (39%). There was an arterial relationship in 34 REZ (superior cerebellar artery in 23, anterior inferior cerebellar artery in 7, and pontine branches of the basilar artery in 4). A venous relationship was seen in 5 REZ. There was vascular contact only in 28 REZ, displacement of the nerve in 7 and grooving of the nerve in 4. We concluded that a neurovascular relationship at the trigeminal root entry zone is not uncommon in an asymptomatic population. The incidence of a vascular relationship in the Indian population seems similar to that in other major series. Electron microscopic studies of the nerve at the site of vascular contact in normal and symptomatic populations may help determine the exact pathogenesis of trigeminal neuralgia.     

Cerebellopontine angle cysticercus and concurrent vascular compression in a case of trigeminal neuralgia

The authors present the case of a 59-year-old woman with an 8 months history of lancinating pain and hyphestesia on the right side of the face along with hearing impairment. She had poor tolerance to carbamazepine. A non-enhancing cystic image was observed at the right cerebellopontine angle on magnetic resonance imaging. The patient underwent surgery. Through a right retromastoid minicraniectomy and under microscopic magnification the VII and VIII cranial nerve complex was found involved by multiple adhesions around a cysticercus. After the cyst was removed a loop of the anteroinferior cerebellar artery was identified compressing the V right nerve at its root entry zone. Decompression was performed by the insertion of a Teflon implant. The postoperative course was uneventful and trigeminal neuralgia (TN) disappeared after surgery. Five previous cases of cranial nerve hyperactive dysfunction syndromes, four of trigeminal neuralgia and one of hemifacial spasm associated to cerebellopontine angle cysticercosis are briefly commented. We suggest that in some of these cases microvascular compression was probably present, and during surgery of cerebellopontine angle cysticercus by either trigeminal neuralgia or hemifacial spasm, vascular compression must be carefully searched and treated when found.     

高分辨率强化3D - SPGR序列评价三叉神经痛患者神经血管的关系

目的 探讨强化三维损毁梯度回波( 3D - SPGR)序列检出三叉神经痛(TN)患者神经血管压迫(NVC)的能力.方法 对37例TN患者行强化3D- SPGR序列扫描,由高年资神经影像学医师评价三叉神经根进入区(REZ)神经与血管的关系,并与显微血管减压术(MVD)术中观察的结果对比.结果 37例患者中,MVD证实36例存在NVC,强化3D-SPGR显示了35例,其敏感性为97.2％,特异性为100％,且MRI所显示的责任血管位置与MVD之间有高度的一致性(K=0.81).在14例三叉神经上颌支疼痛的患者中,12例(85.7％)的NVC位于REZ的内侧,而在16例下颌支疼痛的患者中,13例(81.3％)的NVC位于REZ的外侧,两者之间的差异有统计学意义(P＜0.001).结论 强化3D - SPGR序列是检出TN患者NVC有效的检查方法,将为MVD术前制定治疗方案提供有价值的信息.     

三叉神经根入脑干区MRI形态学研究

目的研究原发性三叉神经痛(TN)患者三叉神经根入脑干区(REZ)的形态结构及其临床应用价值。方法 36例TN患者和20例非TN患者作为健康对照纳入研究。所有受试对象采用3.0TMRI扫描,采用可变翻转角的三维快速自旋回波序列(3D-SPACE)分别扫描两侧REZ区的形态学结构。采取图像分析软件测量分析三叉神经脑池段长度、三叉神经脑桥角、桥小脑角池面积和三叉神经脑池段面积。结果患侧三叉神经脑池段长度的均值、三叉神经脑桥角的均值、桥小脑角池面积的均值以及三叉神经脑池段面积的均值均小于健侧。对照组的三叉神经脑池段长度、三叉神经脑桥角、桥小脑角池面积及三叉神经脑池段面积的均值均大于疾病组。结论三叉神经脑池段较短,三叉神经脑桥角锐利,易发生神经血管冲突,临床上易导致TN;三叉神经脑池段面积缩小提示三叉神经根的萎缩性改变。MRI形态学信息有利于疾病的诊断及手术决策的选择。     

Differences in individual susceptibility affect the development of trigeminal neuralgia

Trigeminal neuralgia is a syndrome due to dysfunctional hyperactivity of the trigeminal nerve,and is characterized by a sudden,usually unilateral,recurrent lancinating pain arising from one or more divisions of the nerve.The most accepted pathogenetic mechanism for trigeminal neuralgia is compression of the nerve at its dorsal root entry zone or in its distal course.In this paper,we report four cases with trigeminal neuralgia due to an unknown mechanism after an intracranial intervention.The onset of trigeminal neuralgia after surgical interventions that are unrelated to the trigeminal nerve suggests that in patients with greater individual susceptibility,nerve contact with the vascular structure due to postoperative pressure and changes in cerebrospinal fluid flow may cause the onset of pain.     

Resolution of trigeminal neuralgia following pontine haemorrhage

Trigeminal neuralgia is characterized by paroxysms of pain in the sensory distribution of the trigeminal nerve usually caused by vascular compression of the trigeminal nerve at the root entry zone. We describe a 57-year-old woman who experienced complete resolution of trigeminal neuralgia following hypertensive pontine haemorrhage.     

Trigeminal neuralgia. Pathophysiology and treatment

Trigeminal neuralgia is a very peculiar disease. The pain, also known as "tic douloureux", is paroxystic and very severe. It can be triggered by a light cutaneous stimulus on a very localized spot on the face (the so-called "trigger zone"). The patient can sometimes benefit from long remissions without any treatment. With the exception of multiple sclerosis and of uncommon cases of posterior fossa tumours or other lesions impinging on the trigeminal nerve, ganglion or root, trigeminal neuralgia is considered as "idiopathic". Some benign abnormality had for long been suspected. The current opinion is now in favour of a "neurovascular conflict": an artery, most often a loop of the superior or anteroinferior cerebellar artery, has an offending contact with the trigeminal nerve root, which results in localized demyelination and ectopic triggering of neuronal discharges. This hypothesis is in agreement with the relief provided by antiepileptic drugs and is supported by recent neuroimaging data. Therapeutic options are reviewed: very efficient drugs are available but fail to provide a significant relief and/or have important side effects in many cases. Surgical alternatives are available, for which guidelines are proposed.     

The significance of three-dimensional MR-defined neurovascular compression for the pathogenesis of trigeminal neuralgia

Three-dimensional MR tomography was used to examine the relationship between symptoms of trigeminal neuralgia and neurovascular compression of the nerve in 18 patients. The intensity of neurovascular interaction was classified according to neuroradiological criteria. We found that a radiologically defined compression or dislocation of the nerve by an artery was always associated with symptoms of trigeminal neuralgia. A simple contanct between vessel and nerve, however, was also observed on the asymptomatic sides of 10 out of 18 patients. In 6 of 18 patients, in contrast, trigeminal neuralgia was present in spite of the absence of neurovascular contact. In accordance with a cited study based on autopsy and intraoperative findings, our findings indicate that, in a certain proportion of cases, trigeminal neuralgia may be caused by neurovascular compression alone, whereas in other cases, other pathogenetic factors may be involved to a varying degree or be even exclusively responsible for the development of trigeminal neuralgia. The possible significance of the method for a preoperative estimation of the success of microvascular decompression of the trigeminal nerve is discussed.     

Trigeminal neuralgia due to multiple sclerosis: ultrastructural findings in trigeminal rhizotomy specimens

Trigeminal neuralgia is a well-recognized complication of multiple sclerosis. In patients with neuralgia not responding to medical treatment or transcutaneous ablative procedures, the pain can often be treated successfully by partial rhizotomy of the trigeminal sensory root. We have examined partial trigeminal rhizotomy specimens from six multiple sclerosis patients, aged between 34 and 77 years, with intractable trigeminal neuralgia lasting between 18 months and 11 years. The rhizotomy specimens were placed in buffered glutaraldehyde immediately after resection, and subsequently processed for electron microscopy. In all cases, this revealed demyelination in the proximal (CNS) part of the nerve root, with associated gliosis and variable inflammation. A consistent feature was the presence of clusters of juxtaposed axons without intervening glial processes. Similar juxtaposition of axons was previously observed in trigeminal neuralgia due to vascular compression of the nerve root. Experimental studies indicate that this arrangement of demyelinated axons is conducive to both spontaneous impulse activity and ephaptic spread of excitation. The demyelination and associated juxtaposition of axons may therefore account for key aspects of the pathogenesis of trigeminal neuralgia.     

颅神经疾病微血管减压术患者的护理体会

目的探讨微血管减压术治疗颅神经疾病的手术前后的护理,使患者能很好地配合治疗,减轻患者术前恐惧、紧张心理,减少术后并发症,提高患者生活质量和增加疗效。方法对83例行微血管减压术的颅神经疾病患者,包括三叉神经痛、面肌痉挛和舌咽神经痛,术前进行心理辅导,术后加强对病情现察及护理。结果 53例三叉神经痛患者中,治愈45例,有效7例,无效1例,后行三叉神经感觉根射频热凝术后治愈;27例面肌痉挛患者中,22例治愈、5例有效;3例舌咽神经痛患者全部治愈。术后17例因三叉神经感觉根切断术后遗留有面部麻木,11例出现轻度面瘫,脑脊液漏3例,口唇疱疹9例,1例出现术后岀血,颅内感染1例。无l例死亡。结论通过术前心理干预,可以患帮助患者克服焦虑与恐惧心理,保证手术的顺利进行;加强术后病情观察,采取有效的治疗及护理,减少术后并发症的发生率,提高患者生活质量和增加疗效。     

A method for intraoperative microneurographic recording of unitary activity in the trigeminal ganglion of patients with trigeminal neuralgia

The etiology of trigeminal neuralgia appears to be vascular compression of the nerve at the root entry zone. However, the physiologic mechanism of trigeminal neuralgia remains uncertain. To gain insight into the pathophysiology of the disorder, we developed a method for intraoperative microneurographic recordings from the trigeminal ganglion of patients with trigeminal neuralgia. The recordings are performed immediately prior to standard percutaneous trigeminal gangliolysis for pain relief. Spontaneous or evoked single- and multi-unit action potential activity can be recorded and the location of receptive fields determined. The method should facilitate the testing of hypotheses concerning the origin of this unique pain disorder.     

Microvascular Decompression for Primary Trigeminal Neuralgia : Short-Term Follow-Up Results and Prognostic Factors

Objective

The aim of this prospective study was to demonstrate the influence of some factors on the prognosis of microvascular decompression in 37 patients with trigeminal neuralgia.

Methods

The results of microvascular decompression (MVD) in 37 patients with trigeminal neuralgia were evaluated at 6 months after surgery and were compared with clinical and operative findings.

Results

The sex of the patient, the patient''s age at surgery, the side of the pain, and the duration of symptoms before surgery did not play any significant roles in prognosis. Also, the visual analogue scale (VAS) of the patient, the duration of each pain attack, and the frequency of pain over 24 hours did not play any significant roles in prognosis. In addition, intraoperative detection of the type of conflicting vessel, the degree of severity of conflict, and the location of the conflict around the circumference of the root did not play any roles in prognosis. The only factors affecting the prognosis in MVD surgery were intraoperative detection of the site of the conflict along the root and neuroradiological compression signs on preoperative magnetic resonance imaging (MRI)/magnetic resonance angiography (MRA).

Conclusion

These findings demonstrated that if neurovascular compression is seen on preoperative MRI/MRA and/or compression is found intraoperative at the root entry zone, then the patient will most likely benefit from MVD surgery.     

Unusual cause for bilateral trigeminal neuralgia: unilateral racemous cysticercus of cerebellopontine angle. Case report

We report the case of a 42-year-old woman with a racemous cystecercus in the right cerebellopontine angle (CPA), who presented with bilateral trigeminal neuralgia. The parasite was completly removed via a right suboccipital craniotomy. On the first postoperative day, the patient indicated that the pain disappeared. The neuralgia was caused by two probable mechanisms: a distortion of the brain stem and compression of the nerve against an arterial loop at the entry zone or arachnoiditis caused by the parasite in the both CPA cisternae. This case demonstrates the advisability of obtaining imaging studies in all patients with trigeminal neuralgia before starting any management. We must always remind that the cysticercus may be a differential diagnosis of CPA lesions.     

磁共振血管成像对舌咽神经痛的的诊断价值(13例临床分析)

目的 分析舌咽神经痛的三维时间飞跃法磁共振血管成像(3D-TOF MRA)的影像学表现,探讨其诊断价值.方法 回顾性分析13例临床诊断舌咽神经痛患者的3D-TOF MRA表现,两名神经影像医生共同阅片达成共识,判断神经血管关系,并与手术结果对比.结果 3D-TOF MRA发现13例舌咽神经痛患者中共14侧舌咽神经出/入延髓区存在血管压迫或接触,其中症状侧舌咽神经有血管压迫或接触12例,无症状侧舌咽神经有血管压迫或接触2 例,本组病例统计学分析表明,舌咽神经痛患者症状的出现与舌咽神经出/入延髓区是否存在血管压迫或接触存在显著相关关系(P＜0.01) ,3D-TOF MRA对舌咽神经痛诊断的敏感性为84.62%,特异性为92.31%.13例有血管压迫或接触引起的舌咽神经痛患者手术证实责任血管9例为小脑后下动脉,1例为小脑前下动脉,1例为椎动脉,1例为未知的静脉,1例为未知的小动脉,而3D-TOF MRA 1例未发现责任血管,2例对责任血管判断不符.结论 3D-TOF MRA对诊断舌咽神经痛具有较高的敏感度及特异度,但对小血管的检出和责任血管的判断上仍存在不足.     

Symptomatic cranial neuralgias in multiple sclerosis: clinical features and treatment

In multiple sclerosis, neuropathic pain is a frequent condition, negatively influencing the overall quality of life. Cranial neuralgias, including trigeminal, glossopharyngeal neuralgias, as well as occipital neuralgia, are typical expression of neuropathic pain. Neuralgias are characterised by paroxysmal painful attacks of electric shock-like sensation, occurring spontaneously or evoked by innocuous stimuli in specific trigger areas. In multiple sclerosis, demyelination in the centrally myelinated part of the cranial nerve roots plays an important role in the origin of neuralgic pain. These painful syndromes arising in multiple sclerosis are therefore considered "symptomatic", in contrast to classic cranial neuralgias, in which no cause other than a neurovascular contact is identified. At this time, the evidence on the management of symptomatic cranial neuralgias in multiple sclerosis is fragmentary and a comprehensive review addressing this topic is still lacking. For that reason, treatment is often based on personal clinical experience as well as on anecdotal reports. The aim of this review is to critically summarise the latest findings regarding the pathogenesis, the diagnosis, the instrumental evaluation and the medical as well as neurosurgical treatment of symptomatic trigeminal, glossopharyngeal and occipital neuralgia in multiple sclerosis, providing useful insights for neurologists and neurosurgeons and a broad range of specialists potentially involved in the treatment of these painful syndromes.     

三维时间飞跃法MRA及图像后处理技术对血管压迫性三叉神经痛的诊断价值

目的　探讨三维时间飞跃法磁共振血管成像 (3D TOFMRA)及其后处理技术 (MPR)对血管压迫性三叉神经痛的诊断价值。方法　两名神经放射科医师盲法分析 38例临床诊断为三叉神经痛患者的 3D TOFMRA基础图像及MPR图像。结果　 (1) 38例三叉神经痛患者中 ,MRI诊断为血管接触或压迫 31例 ,其中有症状侧血管接触或压迫 2 6例。症状侧与影像上三叉神经存在血管接触或压迫有显著相关 (P <0 0 0 5 )。(2 ) 14例以三叉神经第 2支分布区域疼痛为主要症状的患者中 ,85 .7% (12例 )血管压迫神经的中间部位 ;10例以三叉神经第 3支分布区域疼痛为主要症状的患者中 ,70 % (7例 )血管压迫神经的侧方 (P <0 0 0 5 )。结论　 3D TOFMRA及MPR可清晰地显示三叉神经脑池段与毗临血管的关系 ,血管压迫神经的部位与疼痛的区域有一定的相关性     

微血管减压术治疗三叉神经痛的疗效分析

目的介绍乙状窦后锁孔入路微血管减压术（MVD）治疗三叉神经痛（TN）的手术经验,探讨影响手术疗效的因素。方法回顾分析2697例TN患者的临床资料,重点介绍手术操作及注意事项。结果治愈2541例,显效76例,有效48例,无效31例,死亡1例。2190例接受3～240个月的随访,1965例治愈,91例显效,40例有效,30例无效,64例疼痛复发（其中37例行2次手术治愈）。结论异常血管压迫三叉神经入根区并合并局部蛛网膜增厚粘连是TN的主要病因。行MVD同时松解蛛网膜,做到彻底减压。依据病人的不同情况采取相应的减压措施是提高MVD治疗TN效果的重要手段。     

微血管减压术治疗原发性三叉神经痛

目的提出微血管减压术是治疗原发性三叉神经痛的最佳手术方式。方法报告了12例原发性三叉神经痛患者行微血管减压术,其中11例发现三叉神经入脑干区动脉压迫神经根,将压迫血管与神经根分离,在其间植入纤维蛋白海绵或聚四氟乙烯片维持分离状态,术后除1例疼痛减轻外,其余疼痛完全缓解,另1例术中未发现责任血管,但在神经根远侧段发现有粘连,将粘连松解,使神经根游离。结果所有患者术后疼痛减轻或缓解,所有病例无并发症。结论微血管减压术治疗原发性三叉神经痛是去除病因的手术方式,对已行微血管减压术后复发的患者再次行微血管减压术亦可获得满意疗效,作者还认为,神经内镜辅助微血管减压术顺应了当今微侵袭外科的趋势,将有望被更多地用来治疗原发性三叉神经痛。     

Idiopathic and symptomatic trigeminal pain.

The trigeminal reflexes (corneal reflex, blink reflex, masseter inhibitory periods, jaw-jerk) and far field scalp potentials (nerve, root, brainstem, subcortical) evoked by percutaneous infraorbital stimulation were recorded in 30 patients with "idiopathic" trigeminal neuralgia (ITN) and 20 with "symptomatic" trigeminal pain (STP): seven postherpetic neuralgia, five multiple sclerosis, four tumour, two vascular malformation, one Tolosa-Hunt syndrome, and one traumatic fracture. All the patients with STP and two of those with ITN had trigeminal reflex abnormalities; 80% of patients with STP and 30% of those with ITN had evoked potential abnormalities. The results indicate that 1) trigeminal reflexes and evoked potentials are both useful in the examination of patients with trigeminal pain, and in cases secondary to specific pathologies provide 100% sensitivity; 2) in "symptomatic" and "idiopathic" paroxysmal pain the primary lesion affects the afferent fibres in the proximal portion of the root or the intrinsic portion in the pons; 3) primary sensory neurons of the A-beta fibre group are involved in both paroxysmal and constant pain, but in the latter the damage is far more severe.     

Enhanced three-dimensional fast spoiled gradient recalled MRI combined with magnetic resonance angiography for preoperative assessment of patients with trigeminal neuralgia

Microvascular decompression (MVD) is now a standard treatment for trigeminal neuralgia (tic douloureux). The goal of MVD is to decompress the trigeminal root from offending vessels, aiming at a permanent cure with no or little sensory deficit. Preoperative identification of neurovascular compression, therefore, has potentially important implications for patient selection, surgical planning, and outcomes. In this study, enhanced three-dimensional fast spoiled gradient recalled MRI and three-dimensional magnetic resonance angiography with a 3.0-Tesla MRI system were used to detect the anatomic relationship of neural and vascular structures at the trigeminal root entry zone (TREZ) preoperatively. In 27 of 29 patients (93%), surgical findings were consistent with the imaging results. All patients treated with MVD achieved complete pain relief. The usefulness of high-resolution MRI in revealing the neurovascular contact at the TREZ was demonstrated, and it could be used to facilitate the selection of treatment modality. Thus, MVD can be chosen for patients who are most likely to benefit from this intracranial procedure.