Demonstration of neurovascular compression in trigeminal neuralgia with magnetic resonance imaging. Comparison with surgical findings in 52 consecutive operative cases

Until recently, the inability to demonstrate neurovascular compression of the trigeminal nerve preoperatively resulted in surgery being offered only in cases of severe trigeminal neuralgia (TGN), frequently after a prolonged trial of medical treatment and following less invasive procedures, despite the fact that posterior fossa microvascular decompression gives long-term pain relief in 80% to 90% of cases. To assess whether vascular compression of the nerve could be demonstrated preoperatively, high definition magnetic resonance tomographic angiography (MRTA) was performed in 50 consecutive patients, five of whom had bilateral TGN, prior to posterior fossa surgery. The imaging results were compared with the operative findings in all patients, including two patients who underwent bilateral exploration. Vascular compression of the trigeminal nerve was identified in 42 of 45 patients with unilateral symptoms and on both sides in four patients with bilateral TGN. In the last patient with bilateral TGN, neurovascular compression was identified on one side, and on the other side the compressing superior cerebellar artery was separated from the nerve by a sponge placed during previous surgery. There was full agreement regarding the presence or absence of neurovascular compression demonstrated by MRTA in 50 of 52 explorations, but MRTA misclassified four vessels compressing the trigeminal nerve as arteries rather than veins. In two cases, there was disagreement between the surgical and MRTA findings. In the first of these cases, surgery revealed distortion of the nerve at the pons by a vein that MRTA had predicted to lie 6 mm remote from this point. In the second patient, venous compression was missed; however, this patient was investigated early in the series and did not have gadolinium-enhanced imaging. In nine cases, MRTA correctly identified neurovascular compression of the trigeminal nerve by two arteries. Moreover, MRTA successfully guided surgical reexploration in one patient in whom a compressing vessel was missed during earlier surgery and also prompted exploration of the posterior fossa in two patients with multiple sclerosis and one patient with Charcot-Marie-Tooth syndrome, in whom neurovascular compression was identified preoperatively. It is concluded that MRTA is an extremely sensitive and specific method for demonstrating vascular compression in TGN. As a result, open surgical procedures can be recommended with confidence, and microvascular decompression is now the treatment of choice for TGN at the authors' unit. They propose MRTA as the definitive investigation in such patients in whom surgery is contemplated.

Local anesthetic effects in the presence of chronic osteomyelitis (necrosis) of the mandible: implications for localizing the etiologic sites of referred trigeminal pain

The aims of this study were: (1) to demonstrate how reproducible variations in incomplete anesthesia of the inferior alveolar nerve can be used as a guide to locate the etiologic sites of referred trigeminal pain emanating from the mandible; (2) to describe the salient histopathologic features of a lowgrade, nonsuppurative osteomyelitis seen in this patient population. Forty-six patients with idiopathic facial pain were subjected to a specific protocol of local anesthetic injections to sequentially block branches of the mandibular nerve to determine the effects on his/her pain. If this significantly reduced or altered the pain on three separate appointments, then exploratory surgery was conducted near identified zones of unanesthetized gingiva. Blocking (92%), bridging (4%), and divergence (4%) were observed patterns of anesthetic resistance of the mucogingival tissues used to categorize the incomplete anesthesia. A 100% correlation was found between the identified zones of unanesthetized gingiva and the discovery of intramedullary pathology. Medullary fibrosis with ischemic and degenerative changes in the cancellous bone were common findings, along with chronic inflammatory cell infiltrates and clusters of lymphocytes. It is concluded that Ratner's method of diagnostic anesthesia be implemented when searching for occult pain producing pathology of the jaws.

[Trigeminal neuralgia caused by microvascular compression of perforation type]

Of 512 patients of trigeminal neuralgia who had undergone microvascular decompression through a retromastoid craniotomy, 4 were caused by microvascular compression of perforation type. In 3 patients, the perineurium of trigeminal nerve was cut longitudinally, the nerve-tract was separated, the perforating blood vessel was pushed to the distal end, and the vessel was made to leave the nerve sensitive area and then decompression materials were put between the separated nerve-tract. The patients were pain-free and the facial sensation was preserved after operation, and no recurrence occurred in 1 to 3 years after operation. The authors realized that there is a sensitive area near the trigeminal nerve sensory root entry zone. When the blood vessel compresses the sensitive area, trigeminal neuralgia is induced, whereas the vessel decompresses the area, the pain is free. So it is a good evidence for the microvascular compression theory and it is more important than the non-perforation type.

Stereotactic radiosurgery using the gamma knife for acoustic neuromas

PURPOSE

To assess the efficacy and toxicity of stereotactic radiosurgery using the gamma knife for acoustic neuromas.

METHODS AND MATERIALS

Between January 1990 and January 1993, 36 patients with acoustic neuromas were treated with stereotactic radiosurgery using the gamma knife. The median maximum tumor diameter was 21 mm (range: 6-32 mm). Tumor volumes encompassed within the prescribed isodose line varied from 266 to 8,667 mm3 (median: 3,135 mm3). Tumors < or = 20 mm in maximum diameter received a dose of 20 Gy to the margin, tumors between 21 and 30 mm received 18 Gy, and tumors > 30 mm received 16 Gy. The dose was prescribed to the 50% isodose line in 31 patients and to the 45%, 55%, 60%, 70%, and 80% isodose line in one patient each. The median number of isocenters per tumor was 5 (range: 1-12).

RESULTS

At a median follow-up of 16 months (range: 2.5-36 months), all patients were alive. Thirty-five patients had follow-up imaging studies. Nine tumors (26%) were smaller, and 26 tumors (74%) were unchanged. No tumor had progressed. The 1- and 2-year actuarial incidences of facial neuropathy were 52.2% and 66.5%, respectively. The 1- and 2-year actuarial incidences of trigeminal neuropathy were 33.7% and 58.9%, respectively. The 1- and 2-year actuarial incidence of facial or trigeminal neuropathy (or both) was 60.8% and 81.7%, respectively. Multivariate analysis revealed that the following were associated with the time of onset or worsening of facial weakness or trigeminal neuropathy: (a) patients < age 65 years, (b) dose to the tumor margin, (c) maximum tumor diameter > or = 21 mm, (d) use of the 18 mm collimator, and (e) use of > five isocenters. The 1- and 2-year actuarial rates of preservation of useful hearing (Gardner-Robertson class I or II) were 100% and 41.7% +/- 17.3, respectively.

CONCLUSION

Stereotactic radiosurgery using the gamma knife provides short-term control of acoustic neuromas when a dose of 16 to 20 Gy to the tumor margin is used. Preservation of useful hearing can be accomplished in a significant proportion of patients.

Magnetic resonance tomographic angiography: diagnostic value in trigeminal neuralgia

A combination of MRI, MR angiography and MR tomographic angiography (MRTA) was used to study the relationship of the root exit zone of the trigeminal nerve to surrounding vascular structures in seven patients with trigeminal neuralgia (TN) and ten patients with no evidence at a lesion in this region. MRTA is the technique for showing the relationship between vessels, cranial nerves and brain stem. MRTA clearly demonstrated the presence of a vessel at the root exit zone of the trigeminal nerve in all patients with TN. In the ten other patients, examination of 20 trigeminal nerves revealed that only one nerve (5%) was in contact with a vessel at the root exit zone. This study supports vascular compression of trigeminal nerves as a cause of TN, and demonstrates the value of MRTA as noninvasive technique for demonstrating compression.

Trigeminal neuralgia caused by a cerebellopontine-angle lipoma: case report

This report describes the surgical management of a rare trigeminal neuralgia caused by a cerebellopontine (CP)-angle lipoma. A 13-year-old girl presented with typical trigeminal neuralgia in the right mandibular area. Magnetic resonance imaging (MRI) disclosed a lipoma in the right CP angle. A suboccipital craniectomy revealed a lipoma around the 7th and 8th cranial nerves, but there was no apparent lipoma on the surface of the trigeminal nerve. Since the trigeminal nerve swelled only by infiltration of the lipoma, a partial rhizotomy of the involved sensory root was inevitable. The surgery relieved her neuralgia. She remained analgesic in the mandibular area.

Contralateral trigeminal neuralgia: a new clinical manifestation of neurocysticercosis: case report

In cysticercosis, the central nervous system is one of the most commonly affected sites; the clinical manifestations of this disease in the central nervous system can be very severe. The nature and intensity of the signs and symptoms depend on the location of the parasite; cysticeric situated in the cysternae may cause arachnoiditis and vasculitis, but the manifestations are rarely the result of their mass effect. We report the case of a 52-year-old woman with a racemose cysticercus in the left cerebellopontine angle, who presented with contralateral trigeminal neuralgia. The parasite was completely removed via a left suboccipital craniotomy. On the first postoperative day, the patient indicated that the pain had disappeared. The neuralgia was possibly caused by the distortion of the brain stem and the compression of the nerve against an arterial loop at the entry zone. This case demonstrates the advisability of obtaining imaging studies in all patients with trigeminal neuralgia before starting any treatment.

Neurinoma of the trigeminal root and atypical trigeminal neuralgia: case report and review of the literature

BACKGROUND

Neurinomas of the trigeminal nerve are a rare entity: those located in the posterior fossa account for 20% of all cases. In the majority of cases, the clinical presentation begins with fifth cranial nerve involvement producing a constant pain associated with other cranial nerve palsy and cerebellar signs.

METHODS

We report the clinical features, neuroradiological imagings, and management of a case of trigeminal neurinoma located in the cerebellopontine angle, arising from the Vth cranial nerve root, presenting with an atypical trigeminal neuralgia; moreover, we analyze similar cases reported in the literature and we discuss whether pain can be produced by a neurinoma that arises central to the ganglion.

RESULTS

The tumor presented with an atypical trigeminal neuralgia characterized by constant trigeminal pain with paroxystical burns, hyperesthesia and hyperactive autonomic dysfunction. Neuroradiological examinations provided the best preoperative localization of this lesion, allowing better planning of the surgical approach, considering the large size of this tumor. A retromastoid incision and posterior fossa craniectomy approach was used, with complete excision of the tumor. The paraxysmal sharp pain and hyperesthesia disappeared completely, but the constant burning pain persisted although it was less intense. At an 8-month follow-up examination, the patient showed a progressive improvement of clinical symptoms and control magnetic resonance imaging (MRI) showed the complete removal of the neoplasm and the absence of residuals or recurrences.

CONCLUSION

Although in a high percentage of cases of atypical trigeminal neuralgia a neurovascular conflict might be suspected, the review of the present case suggests that the hypothesis of a trigeminal neurinoma must be investigated both with adequate neuroradiological procedures and/or microsurgical exploration of the trigeminal root.

[A case of painful tic convulsif due to cerebellopontine angle epidermoid tumor which could not be clearly detected by MRI]

A case of painful tic convulsif (trigeminal neuralgia and ipsilateral hemifacial spasm) caused by cerebellopontine angle epidermoid tumor is presented. This tumor was compressed to the trigeminal nerve, and became attached to the facial and auditory nerves. The facial nerve exit-zone of brain stem was also compressed by the tumor along with a branch of the posterior inferior cerebellar artery. Total removal of the tumor was carried out and neuralgia and facial spasm disappeared. Painful tic convulsif caused by brain tumor is rare (eight cases in the literature plus our case), but epidermoid tumor is not rare as a cause of this complaint (seven in eight cases). In preoperative examination of this case, we could not detect this epidermoid in the cerebellopontine angle, because this tumor was the same intensity as CSF liquid on magnetic resonance imaging (T1 and T2 weighted image) and exerting hardly any mass effect on the brainstem. On encountering a case of painful tic convulsif of unknown origin despite the usual preoperative examinations, it may be useful that same kind of brain tumor, especially, epidermoid might be concealed in the cerebellopontine angle lesion.

Trigeminal neuralgia associated with osteogenesis imperfecta

Images

Trigeminal neuralgia: association with tentorial meningioma and persistent primitive trigeminal artery

A rare case of trigeminal neuralgia caused by tentorial meningioma associated with a persistent primitive trigeminal artery (PTA) is reported. This case involved a 59-year-old female patient with a more than 6 month history of left trigeminal neuralgia. A left cerebello-pontine angle (CP angle) meningioma was found associated with a right PTA connecting the proximal portion of the cavernous internal carotid artery with the basilar artery, supplying the bilateral superior cerebellar arteries. The tumor was totally removed via the suboccipital approach, which relieved the pain completely. Since the combination of a CP angle meningioma and a PTA is quite rare in patients with trigeminal neuralgia, we have presented this case here.

Tentorial meningioma and painful tic convulsif. Case report

A case is presented of painful tic convulsif caused by a posterior fossa meningioma, with right trigeminal neuralgia and ipsilateral hemifacial spasm. Magnetic resonance images showed an ectatic right vertebral artery as a signal-void area in the right cerebellopontine angle. At operation the tentorial meningioma, which did not compress either the fifth or the seventh cranial nerves directly, was totally removed via a suboccipital craniectomy. The patient had complete postoperative relief from the trigeminal neuralgia and her hemifacial spasm improved markedly with decreased frequency. From a pathophysiological standpoint, the painful tic convulsif in this case was probably produced by the tumor compressing and displacing the brainstem directly, with secondary neurovascular compression of the fifth and seventh nerves (the so-called "remote effect").

Trigeminal neuralgia associated with venous angioma--case report

A 35-year-old male presented with trigeminal neuralgia associated with venous angioma at the root entry zone. Magnetic resonance imaging and angiography demonstrated a venous angioma with a dilated petrosal draining vein, and displacement of the anterior inferior cerebellar artery (AICA). The AICA and dilated petrosal vein were both decompressed, resulting in complete relief from symptoms of trigeminal neuralgia for 30 months. Microvascular decompression rather than resection of venous angioma is recommended for treatment of such cases. The possibility of a venous anomaly should be considered in younger patients with trigeminal neuralgia.

Effect of ketamine, an NMDA receptor inhibitor, in acute and chronic orofacial pain

We examined the analgesic effect of racemic ketamine and its 2 enantiomers in 16 female patients (age: 20-29 years) suffering acute pain after oral surgery and in 7 female patients (age: 42-79 years) suffering chronic neuropathic orofacial pain. All 3 forms of ketamine consistently relieved postoperative pain, (S)-ketamine being 4 times more potent than (R)-ketamine. The analgesic effect was maximal 5 min after i.m. injection and lasted for about 30 min. The 7 patients with neuropathic pain received ketamine at one or several occasions. Four patients (age: 54-79 years) who had suffered pain for more than 5 years did not experience an analgesic effect, whereas 3 patients (age: 42-53 years) who had suffered pain for less than 3 years reported pain relief lasting from 24 h to 3 days. The individual type of response did not depend on the form of ketamine used. The mental side effects were qualitatively similar for the 3 forms of ketamine. Relative to the analgesic effect (S)-ketamine caused more disturbing side effects than did (R)-ketamine. The mean serum concentration of each form of ketamine at the time of maximal effect was close to the approximate Kd value for PCP site occupancy by that particular form. This is in concert with the hypothesis that the effect of ketamine on acute nociceptive pain is due to N-methyl-D-aspartate (NMDA) receptor inhibition and adds to the evidence that NMDA receptors are important for the perception of acute, nociceptive pain in humans.(ABSTRACT TRUNCATED AT 250 WORDS)

[Studies concerning the pathogenesis of trigeminal neuralgia caused by cerebellopontine angle tumors]

It has been well recognized that neurovascular compression can elicit trigeminal neuralgia (TN) and microvascular decompression surgery has become popular as a radical treatment of this clinical symptom. Cerebellopontine (C-P) angle tumors, however, as well known, can also cause TN. Four hundred fifty six patients with TN underwent posterior fossa exploration between 1984 and 1992 in our clinic, and among them, 45 (9.9%) patients harbored C-P angle tumors which were causative of TN. They included 22 epidermoids, 18 meningiomas and 5 neurinomas. The patient population consisted of 35 women and 10 men, ranging in age from 28 to 73 years, with a mean age of 51.7 years. The mean age of the patients of TN with tumors is considerably lower than that of neurovascular compression patients (61.0 years), particularly in cases of neurinomas (44.4 years) and epidermoids (48.0 years) (p < 0.01). Such difference in ages at the onset of symptom may be explained by the fact that the tumor growth in the C-P angle develops earlier than changes of the vasculature of the vertebrobasilar artery system by aging. Anatomical relationships between the 5th cranial nerve and offending arteries or tumors verified at surgery are as follows; Type A: The nerve is totally encased by the tumor. Type B: The axis of the nerve is distorted by the tumor. Type C: The nerve is shifted by the tumor and is compressed by the artery contralaterally. Type D: The nerve is compressed by the artery which was displaced by the tumor.(ABSTRACT TRUNCATED AT 250 WORDS)

[Medulla oblongata compression by tortuous vertebral artery: case report]

We reported a case of a 58-year-old woman who suffered from progressive tetraparesis and sensory disturbance caused by compression of the medulla oblongata brought about by bilateral tortuous vertebral arteries. The neurological examination on admission revealed tetraparesis, sensory disturbance in all modalities below the level of C2, onion-skin pattern sensory disturbance of the face, and motor weakness of the sternocleidomastoid muscles. X-ray films of the cervical spine showed OPLL at the level of C2.3, but on MRI the dural theca was not seen to be compressed at that level. MRI and vertebral angiography demonstrated ventrolateral compression of the medulla oblongata by bilateral tortuous vertebral arteries. After suboccipital craniectomy and C1.4 laminectomy, decompression of the medulla oblongata was performed. Both vertebral arteries were compressing the medulla oblongata at the ventrolateral side. Transposition of the vertebral arteries seemed impossible due to perforating branches to the medulla. After section of the dentate ligaments at C1 level, the medulla oblongata was decompressed and moved backward. Some small pieces of Dacron were inserted between the arteries and the medulla, in order to decrease the pulsatile effect of the vertebral arteries. Postoperatively, the patient's tetraparesis and sensory disturbance gradually improved. There are 6 reported cases concerning compression of the medulla oblongata by the vertebral artery. As MRI becomes more frequently used in neurological situations, it is important to keep the presence of such an entity in mind.

Long-term effects of jawbone curettage on the pain of facial neuralgia

PURPOSE

To evaluate the dimension and duration of pain reduction in patients with facial neuralgias after localization, decortication, and curettage of histologically confirmed inflammatory jawbone lesions of the newly identified form of alveolar avascular osteonecrosis called neuralgia-inducing cavitational osteonecrosis (NICO).

MATERIALS AND METHODS

One hundred ninety patients who could be located retrospectively and who had histories of jawbone curettage for chronic "idiopathic" facial pain, either trigeminal neuralgia (TN) or atypical facial neuralgia/pain (AFN), were identified through surgical pathology reports from four institutions. To assess pain reduction after jawbone surgery, these patients were mailed a modified McGill Pain Survey by investigators with whom they had had no previous professional contact. Patient demographics and clinicopathologic characteristics were also reviewed through surgical pathology specimens and reports.

RESULTS

More than two thirds of the respondents to whom the questionnaire was mailed experienced complete or almost complete disappearance of neuralgic pain immediately or shortly after curettage of jawbone osteonecrosis (NICO), regardless of whether they had previously been diagnosed with TN or AFN. Thirty percent, however, experienced local recurrence of jaw inflammation and facial pain, and one third developed at least one and as many as 12 additional foci of histologically confirmed osteonecrosis. Despite this, however, the long-term (average, 4.6 years) abatement of neuralgic pain was total or almost total in 74% of treated patients.

CONCLUSIONS

Neuraglia-inducing cavitational osteonecrosis appears to be associated with at least some cases of facial neuralgia, or with a pain so similar as to be clinically indistinguishable. Decortication and curettage dramatically reduces or eliminates this intense pain in two of every three patients, although multiple surgeries may be required, and additional sites of osteonecrosis may occur. It is recommended that NICO be included in the differential diagnosis of idiopathic facial pain syndromes.

Trigeminal neuralgia and multiple sclerosis. A complex diagnosis

Trigeminal neuralgia is a well-recognized complication in patients with multiple sclerosis. A case report is presented that describes multiple sclerosis in a middle-aged man with otherwise classical unilateral trigeminal neuralgia who demonstrated a variable response to pharmacologic and surgical intervention. The case highlights the difficulties of diagnosis when trigeminal neuralgia occurs concurrently with multiple sclerosis.

Encircling method of trigeminal nerve decompression for neuralgia caused by tortuous vertebrobasilar artery: technical note

BACKGROUND

Surgical treatment of trigeminal neuralgia caused by dolichoectatic vertebrobasilar artery presents a difficult problem because of the immobility and the stiffness of the atherosclerotic vessel walls.

METHODS AND RESULTS

A patient with trigeminal neuralgia was treated by a new method of vascular decompression. Preoperative studies demonstrated a dolichoectatic vertebrobasilar artery, and compression of the trigeminal nerve by the artery was confirmed during surgery. The fifth nerve was mobilized away from the artery using a ring-shaped piece of silicone rubber. Postoperatively, the facial pain completely resolved without complication.

CONCLUSIONS

Trigeminal neuralgia due to nerve compression by tortuous vertebrobasilar artery was successfully treated by an encircling method of vascular decompression.