Management of 1000 vestibular schwannomas (acoustic neuromas): clinical presentation

OBJECTIVE

Despite good knowledge of the key symptoms of vestibular schwannomas and their significance for surgical results, the evolution of symptoms and signs and their relation to tumor extension still need thorough investigation.

METHODS

From 1978 to 1993, operations were performed by the same surgeon (M.S.) on 1000 vestibular schwannomas at the Neurosurgical Department of Nordstadt Hospital. The vestibular schwannomas were diagnosed in 962 patients, including 522 female patients (54%) and 440 male patients (46%); the mean age was significantly higher in female patients (47.6 yr) than in men (45.2 yr). We focused our analysis on the incidence of subjective disturbances versus objective morbidity, on the sequence of symptom onset, and on symptom duration and symptomatology versus tumor size and extension.

RESULTS

The most frequent clinical symptoms were disturbances of the acoustic (95%), vestibular (61%), trigeminal (9%), and facial (6%) nerves. Symptom duration was 3.7 years for hearing loss, 1.9 years for facial paresis, and 1.3 years for trigeminal disturbances. Symptom incidence and duration did not strictly correlate with tumor size. Key symptoms of various tumor extension classes precipitated the diagnosis, such as trigeminal disturbances in large tumors with brain stem compression or tinnitus in small neuromas. In cases of trigeminal or facial nerve symptoms, the overall duration of symptomatology was much shorter. According to the subjective perception of the patients, between only one- and two-thirds of nerve disturbances were noticed. Patients with preoperative deafness had become deaf either chronically (23%) or suddenly (3%); even in cases of moderate hearing deficit that lasts a long time, deafness can occur suddenly. The rate of tinnitus was higher in hearing than in deaf patients; however, deafness does not mean relief from tinnitus, because this symptom persists in 46% of preoperatively deaf patients. Vestibular disturbances most often occur as some unsteadiness while walking or as vertigo, and the symptoms frequently are fluctuating, not constant.

CONCLUSION

Differences in tumor biology can be underestimated and are not visible on radiological scans. For example, intrameatal tumors, despite their small size, present with a duration of symptoms that is representative of the larger tumors and are most frequently associated with vestibular symptoms and with tinnitus. Large tumors with brain stem compression present with relatively shorter symptom durations and at a younger age; both factors are suggestive of especially fast tumor growth. The clinical findings presented in this study promote new consideration of the dynamics of tumor growth and of the affected neural tissues.

Treatment of trigeminal neuralgia by percutaneous radiofrequency rhizotomy

Percutaneous radiofrequency rhizotomy (PSR) is recognized as a simple, effective, and safe surgical treatment for trigeminal neuralgia. Rates of pain recurrence after PSR are the lowest versus those of other percutaneous procedures, and similar to those of microvascular decompression.

Percutaneous balloon compression of the trigeminal nerve

Balloon compression is a simple and effective percutaneous approach for the treatment of classic trigeminal neuralgia or trigeminal neuralgia secondary to multiple sclerosis. The operation injures large myelinated fibers, removing the "trigger" to the presumed ephaptic transmission of pain. Because unmyelinated fibers, which mediate the corneal reflex, are preserved, compression may be of advantage in the treatment of first division pain, since the corneal reflex is mediated by the small unmyelinated fibers. In the author's series of 141 consecutive patients treated by balloon compression, overall recurrence rate was 26%, with 80% of patients experiencing mild numbness postoperatively.

Trigeminal neuralgia

Trigeminal neuralgia is a sudden, severe, brief, recurrent, stabbing pain in the distribution of the trigeminal nerve. It is a rare condition whose etiology remains unknown. Diagnosis is by careful history and there are few investigations that are of value in the management of this condition. Management is initially medical with anticonvulsant drugs being the primary drugs. If the drugs are no longer effective or tolerated then surgical management needs to be considered. Surgery can be at a variety of different levels along the pathway of the trigeminal nerve. Each procedure has its advantages and disadvantage. It is crucial that throughout treatment the patient has been given fully informed choice.

Experience with cerebellopontine angle epidermoids

OBJECTIVE

Cerebellopontine angle (CPA) epidermoids, although of benign nature, are of considerable neurosurgical interest because of their close proximity and adherence to the cranial nerves and the brain stem. We describe our experience and attempt to correlate the final outcomes with the extent of surgical removal.

METHODS

Twenty-five consecutive patients with CPA epidermoids that were surgically treated were reviewed, and the final outcomes were assessed.

RESULTS

Thirteen patients had trigeminal neuralgia. In 7 of the 13 patients, trigeminal neuralgia was the only presenting feature. The epidermoid was confined to the CPA in each of 6 patients, and in each of 18, it had varying degrees of supratentorial extension. One patient had a predominant supratentorial epidermoid with extension to the CPA. The lesions were totally excised in 12 patients. Near-total removal was accomplished in eight patients, and in the remaining five, partial removal was accomplished. Transient worsening of the cranial nerve functions occurred in 11 patients, probably as a result of aggressive dissection of the capsule from the cranial nerves. In 9 of the 11 patients, the cranial nerve functions improved by the time of discharge. All of the patients who had trigeminal neuralgia were relieved of their symptoms. Eighteen patients were followed up for a mean period of 42 months, and none had symptoms of recurrence.

CONCLUSION

Aggressive surgical removal results in transient but significant cranial nerve dysfunction in the postoperative period. A conservative approach is indicated for patients in whom the capsule is adherent to the brain stem and the cranial nerves.

Case report: sequential bilateral carotid dissection leading to Raeder's syndrome

A 39-year-old man complained of unilateral headache, diplopia and marked anterior neck oppression "like a necklace". MRA was used to study this case of subsequent bilateral internal artery dissection (ICAD) which initially appeared as Raeder's syndrome. MRA proved to be a non-invasive alternative for studying stenosis, occlusions and dissections of the intracranial and extracranial vessels.

Magnetic resonance imaging of vertebrobasilar ectasia in trigeminal neuralgia

Vertebrobasilar ectasia is a rare cause of typical trigeminal neualgia. In a recently published large series only thirty-one (2%) of 1404 consecutive patients with vascularly determined neuralgia were found to have vertebrobasilar compression. We present three patients with trigeminal neuralgia caused by vertebrobasilar ectasia, who were evaluated with high resolution magnetic resonance imaging (MRI). MRI studies provided accurate information on the anatomical location and course of the ectatic vessel in the cerebellopontine angle and the caused mass effect on the brainstem. With gadolinium-enhancement vascular compression of the trigeminal nerve was demonstrated clearly. Surgery confirmed compression of the fifth nerve by an ectatic and tortuous vertebrobasilar artery in two cases. Following microvascular decompression neither patient experienced further pain. The third patient was treated with a ventriculoperitoneal shunt, as he developed occlusive hydrocephalus caused by the vertebrobasilar dolicho-ectasia. MRI is useful in the evaluation of trigeminal neuralgia as it excludes other aetiologies such as tumour or arteriovenous malformation, but also demonstrates cranial nerve compression by ectatic vertebral arteries.

Recurrent trigeminal neuralgia caused by an inserted prosthesis: report of two cases

We report two cases of recurrent trigeminal neuralgia caused by an inserted prosthesis. Teflon material or polyurethane sponge inserted between the trigeminal nerve and the superior cerebellar artery became hardened and compressed the trigeminal nerve 17 months (Teflon) and 9 years (polyurethane sponge) respectively after the initial surgery. On the basis of these cases, it it suggested that actual decompression of the trigeminal nerve is important in surgery for trigeminal neuralgia, and that the prosthesis should not touch the trigeminal nerve.

Raeder's paratrigeminal syndrome: a case report

Raeder's paratrigeminal syndrome is an uncommon neurologic disorder characterized by oculosympathetic paralysis, including ptosis and miosis. In the ED, this syndrome can be easily confused with Horner's syndrome, although with Raeder's syndrome trigeninal nerve irritation and preservation of facial sweating are noted. This report reviews a case of a 62-year-old man who presented to the ED with signs and symptoms consistent with Raeder's syndrome. MRI with angiography revealed a carotid artery dissection, and the patient was admitted and anticoagulated. The syndrome has been associated with head trauma, hypertension, vasculitis, migraine headaches, parasellar mass lesions, and internal carotid artery dissections. Hence, treatment of the patient who has Raeder's syndrome is dependent on the specific underlying lesion.

Treatment of chronic paranasal sinus pain with minimal sinus disease

A common problem for otolaryngologists are patients who present with recurrent, persistent sinus pain that appears out of proportion to the findings on physical examination. Often these patients have a history of recurrent sinusitis that required antibiotics or surgical intervention. Many have had repeated surgical procedures because of this pain. Other common past medical histories may include allergic rhinitis, facial trauma, or dental disease. Patients who have experienced documented acute sinusitis in the past will often present de novo with similar symptoms, but lack any objective evidence of a new active sinus infection. However, the diagnosis of sinusitis is not clearly removed from the patient's or clinician's mind, and the patient is further frustrated by the lack of adequate diagnosis, treatment, and resolution of symptoms. These patients may or may not be experiencing an upper respiratory tract infection or allergy with nasal drainage. Often, they are emotionally distraught from recurrent and persistent pain, the lack of resolution of their symptoms, dependency on narcotics and other analgesics, multiple consultations with a variety of clinicians, and the impingement of their symptoms on employment, interpersonal relationships, and societal and family obligations. If sinusitis is not found to be present, the otolaryngologist must help the patient understand this point, reassure him or her that the otolaryngologist will still be vigilant for the development of sinusitis, and refocus the history and workup for some other cause of the recurrent and persistent paranasal pain. We review various treatment approaches to paranasal pains that are not the result of sinusitis.

Trigeminal neuralgia in nasopharyngeal carcinoma

Tumours at the skull base may show perineural infiltration of the mandibular nerve. Subsequent retrograde spread into the cavernous sinus, Gasserian ganglion, the trigeminal nerve and the pons may be seen. The patient, a known and treated case of nasopharyngeal carcinoma (NPC), complained of trigeminal neuralgia and difficulty in chewing. Magnetic resonance imaging (MRI) revealed a Gasserian ganglion and trigeminal infiltration with resultant atrophy of the muscles innervated by the mandibular nerve. Proximal cranial nerve involvement should be suspected in patients with skull base malignancy presenting with trigeminal neuralgia. MRI is the modality of choice in delineating the pathological process.

[Identification of offending vessels in trigeminal neuralgia and hemifacial spasm using SPGR-MRI and 3D-TOF-MRA]

We investigated 100 consecutive patients with trigeminal neuralgia (TN) and 53 patients with hemifacial spasm (HFS) concerning the anatomical relationship between the root entry (exit) zone (REZ) of cranial nerve and the offending artery, using spoiled GRASS MRI (SPGR-MRI) and three dimensional-time of fly-MRA (MRA). In 67 of 100 (67%) patiets with TN, this new radiological method, SPGR-MRI and MRA demonstrated the relationship between the fifth cranial nerve root and offending artery causing neurovascular compression (NVC), and in 46 of 53 (87%) with HFS, demonstrated the similar relationship between seventh and eighth nerve complex and offending artery. Microvascular decompression (MVD) was performed in 10 with HFS, and NVC of the REZ of the facial nerve caused by the offending artery was exactly predicted by SPGR-MRI and MRA in 9 (90%). The combination of SPGR-MRI and MRA is very useful for demonstrating NVC as the cause of TN and HFS. On the other hand, we investigated asymptomatic 206 trigeminal and 253 facial nerves about the relationship between their REZ and the surrounding structures using the similar method. The contact of REZ of cranial nerve with surrounding artery is demonstrated in 31.6% of trigeminal nerves and in 22.5% of facial nerves. These results indicate that the contact of REZ of cranial nerve with surrounding artery is not rare in healthy subjects, though causing TN and HFS in particular patients. In this context, we discussed the difference between the contact which is asymptomatic and the compression which is symptomatic.

Relationship of the infraorbital nerve and vessels in the pathogenesis of idiopathic trigeminal neuralgia: a theoretical discussion and cadaveric study

Many etiologies have been postulated to explain the pathogenesis of Trigeminal Neuralgia (TN). Most theories focus on a demyelinating process resulting in ephaptic transmission and recruitment of small pain fibers or a restrictive relationship of the superior cerebellar arteries and the trigeminal nerve roots at the level of the pons which may lead to demyelination. It is postulated that vasodilation or constriction of these vessels in a confined bony canal can create localized regions of demyelination and restrictive relationships creating painful stimuli. It is the purpose of this study to grossly investigate the relationship of the infraorbital nerve and vessels passing through the infraorbital canal to discuss whether their relationship may play a role in the pathogenesis of idiopathic TN. Patterns of relationship have been elucidated and will be described. This preliminary gross anatomical study should set the framework from which to base further microscopic and clinical studies.

Dural arteriovenous malformation manifesting as tic douloureux

BACKGROUND

Although cerebral arteriovenous malformation (AVM) is an established cause of trigeminal neuralgia, dural AVM has rarely been reported to cause tic douloureux. Treatment of dural AVM in the tentorial and torcular regions by transarterial embolization is rarely curative. It has recently been proposed that many cranial dural AVMs with leptomeningeal venous drainage require only interruption of the draining vein as it enters the subarachnoid space for successful, lasting elimination.

CASE REPORT

We present a case of 65-year-old man with typical trigeminal neuralgia caused by a dural AVM. Carotid angiography revealed a dural AVM in the petrotentorial region with enlarged and serpiginous draining veins, which compressed the trigeminal nerve. Facial pain had been completely relieved for 2 months after successful transarterial embolization, but the symptom recurred. The patient subsequently underwent surgical interruption of the draining veins just beneath the cerebellar tentorium. The dural AVM disappeared, and the trigeminal neuralgia was completely relieved.

CONCLUSION

The literature concerning the etiology of tic douloureux is reviewed and the selection of treatment modality of this case is discussed. The striking clinical and radiologic improvement in this case emphasizes the pivotal role of simple interruption of the arterialized vein for petrotentorial dural AVMs, which are not amenable to cure by endovascular procedures.

Isolated trigeminal neuralgia secondary to distal anterior inferior cerebellar artery aneurysm

A 43-year-old woman complaining of severe pain of the right side of the face was admitted to the Department of Neurosurgery. It had been present for three months and diagnosed as trigeminal neuralgia. The CT scan without contrast material had been considered normal at that time. Three months later, after a favourable response to carbamazepine, she suddenly developed right occipital headache and drowsiness. On admission, she was alert, and neurological examination revealed only mild neck stiffness. Computed tomographic scan demonstrated an acute hematoma in the right cerebellopontine angle and in the fourth ventricle. Vertebral angiography revealed an aneurysm of the right anterior inferior cerebellar artery (AICA). A posterior fossa approach disclosed a large, nearly totally thrombosed, saccular AICA aneurysm, which showed minimal compression to the pons at the trigeminal root entry zone. The aneurysm was clipped and excised. She showed an excellent recovery and was free of pain in the early postoperative period and at the last examination 16 months later. Aneurysms in the distal AICA are very rare lesions. Only 31 cases have been published so far. Distal AICA aneurysm in an extremely unusual cause of trigeminal neuralgia secondary to aneurysmal compression. The literature concerning AICA aneurysms and their clinical manifestations is reviewed and discussed.

Magnetic resonance imaging used to assess patients with trigeminal neuralgia

To assess the value of magnetic resonance imaging in the evaluation of trigeminal neuralgia, 51 patients were studied by magnetic resonance imaging after a trigeminal protocol. Clinical and magnetic resonance imaging results were correlated. Seventeen (33%) nonvascular abnormalities and 27 (53%) vascular contacts or compressions of the trigeminal nerve were demonstrated. Of the patients younger than of 29 and 39 years of age, 100% and 45%, respectively, had a tumor or multiple sclerosis compared with 20% and 18% of those older than 40 and 60 years of age, respectively. One third of the patients with pain in more than one branch of the trigeminal nerve had tumors. On the basis of this study, magnetic resonance imaging may be useful in discovering underlying pathoses associated with trigeminal neuralgia if patients have failed to respond to an initial conservative treatment. The patients most likely to exhibit significant magnetic imaging resonance findings are young and with pain in more than one trigeminal branch.

Twenty-five years experience in the treatment of trigeminal neuralgia. Comparison of three different operative procedures in forty-nine patients

A series of 49 patients with trigeminal neuralgia (TN) were treated by three different surgical procedures: (1) peripheral ablative procedures in 10 patients; (2) percutaneous rhizotomy in 17 patients and (3) intracranial rhizotomy (IR) in 22 patients. On the basis of surgical treatment, the concept that neurovascular compression is a mechanical factor in the aetiology of TN was supported in 14 to 18 patients who underwent posterior fossa exploration. The results support the conclusion that retromastoid craniectomy with IR is the procedure of choice for the majority of patients with TN.

Trigeminal neuralgia due to vascular compression in multiple sclerosis--post-mortem findings

A 71-year-old male with multiple sclerosis and trigeminal neuralgia due to vascular compression underwent multiple radio-frequency nerve lesioning bilaterally. He was anaesthetic on the left side and required right microvascular decompression. He died after this procedure. The pathology of the pons and the effects of treatment are described.

Trigeminal neuralgia related to cerebellopontine angle tumors

A review of 30 cases with cerebellopontine angle tumors was carried out to identify patients with trigeminal neuralgia (TN) at presentation and to compare them with patients without TN. The study shows that dermoid tumors and the presence of tumor at the apex of petrous bone on CT are associated with a significantly higher incidence of TN, while the incidence did not appear to be influenced by age, sex, or size of tumor. In all patients but one (with medulloblastoma) that had surgery, there the TN disappeared following total or subtotal excision of the tumor, providing the trigeminal nerve was well decompressed. Patients with TN should be investigated carefully by CT or MRI irrespective of their age or the absence of neurological signs.