Acoustic neurinomas associated with vascular compression syndromes

Outcomes of Trigeminal Ganglion Sparing Surgical Resection of Nonacoustic Cerebellopontine Angle Tumors Causing Trigeminal Neuralgia

OBJECTIVE

Tumors may be responsible for up to 5% of trigeminal neuralgia cases. Predictors of long-term pain relief after surgical resection of various cerebellopontine angle tumor types are not well understood. Previous studies found that size and extent of resection predict long-term pain status, although resection of tumor involving the trigeminal ganglion may be associated with high morbidity. This study evaluated predictors of TN pain freedom after resection of a nonacoustic CPA tumor, with avoidance of any portion involving the TG.

METHODS

In a retrospective cohort study, we evaluated clinical outcomes and complications after surgical resection of nonacoustic CPA tumors with purposeful avoidance of the TG causing trigeminal neuralgia. The primary outcome was pain-freedom. We performed logistic regression analyses to examine the relationship between pain-freedom at last follow-up and age, side of symptoms, preoperative symptom duration, tumor diameter, tumor type, and concurrent neurovascular compression (NVC).

RESULTS

Of 18 patients with nonacoustic CPA tumors causing TN treated with surgical resection, 83.3% were pain-free at last follow-up (mean 44.6 months). Age (P = 0.12), side (P = 0.41), preoperative symptom duration (P = 0.85), tumor diameter (P = 0.29), tumor type (P = 0.37), and NVC presence (P = 0.075) were not associated with long-term pain freedom.

CONCLUSIONS

This study provides additional evidence that various tumor types causing TN may safely undergo surgical resection and decompression of the trigeminal nerve to treat TN. This study presents a cohort of patients that underwent resection of a nonacoustic CPA tumor, with purposeful avoidance of the TG to minimize complications, demonstrating high rates of long-term pain freedom.

Delayed blink R1 latency in a patient with trigeminal neuralgia due to a contralateral vestibular schwannoma: An illustrative case

Background

Although the blink reflex (BR) is effective in objectively evaluating trigeminal neuropathy, few studies have demonstrated its effect on trigeminal neuralgia (TN). The authors report a patient with TN due to contralateral vestibular schwannoma (VS) functionally diagnosed by delayed R1 latency of the BR.

Case Description

A 36-year-old man presented with left-sided deafness and paroxysmal facial pain in the right V1-3 area. Magnetic resonance imaging (MRI) showed a solid cystic mass compressing the right pons and left brainstem at the left cerebellopontine angle. Although preoperative BR evoked by right supraorbital nerve stimulation-induced delayed ipsilateral R1 latency and normal ipsilateral and contralateral R2 responses, the BR latency evoked by left supraorbital nerve stimulation was normal, indicating deficits in the principal nucleus of the trigeminal nerve in the right pons. The symptoms of TN disappeared after the removal of the VS. Postoperative MRI showed subtotal removal of the tumor and sufficient decompression of the pons and cerebellopontine cistern. The R1 latency returned to normal 50 days after surgery.

Conclusion

The perioperative BR test was not only useful for objective evaluation of the localization of trigeminal neuropathy but also correlated with the symptoms of TN.

Open surgery vs. stereotactic radiosurgery for tumour-related trigeminal neuralgia: A systematic review

BACKGROUND

Secondary trigeminal neuralgia is a facial pain in trigeminal nerve dermatome caused by an underlying disease, such as cerebellopontine angle tumours. Treatment options to relieve the pains were surgical tumour resection and stereotactic radiosurgery of the tumour or trigeminal nerve. This study aims to review the efficacy of open surgery and stereotactic radiosurgery and recommend the treatment of choice for secondary trigeminal neuralgia due to cerebellopontine angle tumours.

METHOD

The inclusion criteria were studies covering patients with trigeminal neuralgia associated with cerebellopontine angle tumours that were treated with either open surgery or stereotactic radiosurgery and reported pain outcomes after treatment. Non-English articles or studies with a population of less than five were excluded. We systematically searched studies from PubMed, Ebscohost, and Cochrane Library from inception until December 20, 2021. Several works of literature from manual search were also added. Selected articles were appraised using a critical appraisal tool for prognostic studies.

RESULT

Included articles were 26 retrospective studies and one prospective study comprising 517 patients. Of 127 schwannomas, 226 epidermoids, 154 meningiomas, and ten other tumours, 320 cases received surgical tumour excision with or without MVD, 196 had tumour-targeted radiosurgery, and 22 underwent nerve-targeted radiosurgery. In surgical series, 92.2 % gained pain improvement, 2.8 % were unchanged, and 4.5 % had recurrence; none of the patients had worsened outcomes. In cases treated with tumour-targeted radiosurgery, the improvement rate was 79.1 %, unchanged at 14.3 %, recurrence at 26.5 %, and worse symptoms rate after the intervention was 6.6 %. Six patients with recurrent pain after tumour-targeted radiosurgery received secondary nerve-targeted radiosurgery with improved outcomes. Only one patient in our review underwent primary nerve-targeted radiosurgery, and the result was satisfactory. One study treated 15 patients with a single session of tumour-targeted and nerve-targeted radiosurgery, with an improvement rate of 93.3 % and a recurrence rate of 21.4 %.

CONCLUSION

Open surgery releasing the nerve root from compressive lesions is advocated to be the first-line treatment to gain satisfactory outcomes. Total removal surgery is recommended if possible. Nerve-targeted radiosurgery should be reserved as a secondary treatment for recurrent cases.

Trigeminal neuralgia in patients with cerebellopontine angle tumors: should we always blame the tumor? A case report and review of literature

OBJECTIVES

This report seeks to highlight a pitfall that may be encountered in the management of patients with trigeminal neuralgia with imaging showing both neurovascular conflict as well as tumors.

CASE PRESENTATION

A case of a 53 year old male with simultaneous neurovascular conflict and a vestibular schwannoma with trigeminal neuralgia is presented and the management is discussed with reference to managing this particular subset. Pain was noted to be likely generated by neurovascular conflict and not by the tumor, which is usually not the case.

CONCLUSIONS

It is suggested that in such cases, microvascular decompression should always be performed in addition to removal of the tumor.

A Case Report of Hemifacial Spasm Caused by Vestibular Schwannoma and Literature Review

BACKGROUND

Most cases of hemifacial spasm result from mechanical compression at the root exit zone of the facial nerve by vascular loops, and only a few cases are caused by vestibular schwannoma.

CASE PRESENTATION

We report a case of symptomatic hemifacial spasm induced by a small vestibular schwannoma that was totally resected. A 64-year-old man was admitted to our department with a 14-month history of symptomatic right-sided hemifacial spasm. During the process of microvascular decompression, no definite vessel was found to compress the facial nerve. By further exploration of regions other than root exit zone, a small vestibular schwannoma compressing the internal auditory canal portion of facial nerve from the ventral side was discovered. Resection of the tumor was then conducted. The symptoms of hemifacial spasm disappeared immediately after surgery.

CONCLUSIONS

We should be aware that magnetic resonance imaging is not always precise and perhaps misses some miniature lesions due to present image technique limitations. A small vestibular schwannoma might be the reason for HFS, although preoperative magnetic resonance tomography angiography showed possible vascular compression at the facial nerve root. More importantly, a full-length exploration of the facial nerve is in urgent need to find potential compression while performing microvascular decompression for HFS patients.

Small vestibular schwannoma presented with trigeminal neuralgia: illustrative case

BACKGROUND

A vestibular schwannoma (VS) presenting with paroxysmal facial electric shock pain, that is, trigeminal neuralgia (TN), is relatively rare. Furthermore, TN is extremely rare in small VSs.

OBSERVATIONS

Herein, the authors report the case of a 52-year-old woman with a complaint of right TN. Magnetic resonance (MR) imaging revealed a right VS of 12-mm diameter that compressed the trigeminal nerve. Although she did not report any hearing impairment, audiometry revealed decreased high-frequency range on the right side. The tumor was excised using the right retrosigmoid approach, and TN was confirmed to be caused by direct compression of the trigeminal nerve by the VS. Sufficient decompression of trigeminal nerve was done. The proximity of the trigeminal nerve root to the vestibular nerve root was the cause of TN. TN disappeared immediately after surgery, and there was no worsening of hearing impairment and facial paralysis.

LESSONS

It is important to remember that TN may occur with direct tumor compression, even in small VSs. A preoperative 3-dimensional MR cisternogram/angiogram fusion image clearly showed direct tumor compression of the trigeminal nerve and the absence of responsible vessels, which was useful for surgical planning.

Facial pain and sensory outcomes following resection of tumors compressing the trigeminal nerve

OBJECTIVE

Tumors compressing the trigeminal nerve can cause facial pain, numbness, or paresthesias. Limited data exist describing how these symptoms change after resection and what factors predict symptom improvement. The objective of this study was to report trigeminal pain and sensory outcomes after tumor resection and identify factors predicting postoperative symptom improvement.

METHODS

This retrospective study included patients with tumors causing facial pain, numbness, or paresthesias who underwent resection. Trigeminal schwannomas were excluded. Logistic regression, recursive partitioning, and time-to-event analyses were used to report outcomes and identify variables associated with facial sensory outcomes.

RESULTS

Eighty-six patients met inclusion criteria, and the median follow-up was 3.1 years; 63 patients (73%) had meningiomas and 23 (27%) had vestibular schwannomas (VSs). Meningioma patients presented with pain, numbness, and paresthesias in 56%, 76%, and 25% of cases, respectively, compared with 9%, 91%, and 39%, respectively, for patients with VS. Most meningioma patients had symptoms for less than 1 year (60%), whereas the majority of VS patients had symptoms for 1-5 years (59%). The median meningioma and VS diameters were 3.0 and 3.4 cm, respectively. For patients with meningiomas, gross-total resection (GTR) was achieved in 27% of patients, near-total resection (NTR) in 29%, and subtotal resection (STR) in 44%. For patients with VS, GTR was achieved in 9%, NTR in 30%, and STR in 61%. Pain improved immediately after tumor resection in 81% of patients and in 92% of patients by 6 weeks. Paresthesias improved immediately in 80% of patients, increasing to 84% by 6 weeks. Numbness improved more slowly, with 52% of patients improving immediately, increasing to 79% by 2 years. Pain recurred in 22% of patients with meningiomas and 0% of patients with VSs. After resection, the Barrow Neurological Institute (BNI) facial pain intensity score improved in 73% of patients. The tumor diameter significantly predicted improvement in BNI score (OR 0.47/cm larger, 95% CI 0.22-0.99; p = 0.047). Complete decompression of the trigeminal nerve was associated with qualitative improvement in pain (p = 0.037) and decreased pain recurrence (OR 0.08, 95% CI 0.01-0.67; p = 0.024).

CONCLUSIONS

Most patients with facial sensory symptoms caused by meningiomas or VSs experienced improvement after resection. Surgery led to immediate and sustained improvement in pain and paresthesias, whereas numbness was slower to improve. Patients with smaller tumors and complete decompression of the trigeminal nerve were more likely to experience improvement in facial pain.

[Trigeminal radiculopathy in vestibular schwannomas]

OBJECTIVE

To evaluate the correlation of trigeminal radiculopathy with anatomical relationships of trigeminal nerve root, brainstem, tumors and vessels in patients with vestibular schwannomas.

MATERIAL AND METHODS

A retrospective analysis included 153 patients (106 females and 47 males aged 22-82 years) with vestibular schwannomas who underwent surgery via retromastoid approach. Preoperative trigeminal radiculopathy (facial pain and sensory disturbances) was examined after microsurgical resection. Brainstem compression was analyzed by comparison of transverse size of contralateral to vestibular schwannoma half of brainstem and ipsilateral side.

RESULTS

Tumor-induced brainstem and trigeminal nerve compression was found in 115 cases. Sixty-four of these patients had trigeminal radiculopathy symptoms. Degree of brainstem compression was significantly higher in trigeminal radiculopathy group. Facial hypoesthesia was found in 61patients, trigeminal neuralgia - in 5 cases, neuropathic pain - in 3 patients. Thirty-seven patients without brainstem compression had no trigeminal nerve involvement. One patient had trigeminal neuralgia following compression by superior cerebellar artery. Total resection with brainstem and trigeminal nerve decompression were performed in all cases. Isolated or combined compression of trigeminal nerve root was noted in 9 patients with trigeminal neuralgia and neuropathic pain, in 2 with facial numbness and in 2 patients without trigeminal symptoms. In case of trigeminal neuralgia following compression by superior cerebellar artery, vascular decompression was performed only in patients with facial pain and numbness. Facial pain completely resolved in all patients. Complete or partial sensory restoration was noted in 25 cases. No facial sensory disorders were noted in 26 cases, transient sensory deterioration - in 10 patients.

CONCLUSION

Trigeminal radiculopathy is caused by severe brainstem compression following vestibular schwannomas and usually results sensory disturbances and rarely facial pain. The impact of tumor on trigeminal nerve root and brainstem trigeminal pathways can be accompanied by vascular compression by superior cerebellar artery. Regression of trigeminal radiculopathy symptoms after resection of vestibular schwannoma is caused by decompression of trigeminal nerve root and brainstem. In case of concomitant neurovascular syndrome, vascular decompression is indicated.

[Anatomical rationale for surgical treatment of trigeminal neuralgia combined with cerebellopontine angle tumors]

Trigeminal neuralgia (TN) can be combined with tumors of the cerebellopontine angle (CPA). The optimal surgical management in these cases depends on the anatomical relationship of the trigeminal nerve root (TNR) with tumors and vessels. The purpose of this study is to evaluate variants of the anatomical relationship between the TNR and the surrounding structures as well as to analyze the results of using various surgical techniques for treatment of TN in CPA tumors.

MATERIAL AND METHODS

We performed a retrospective analysis of 51 patients (38 females and 13 males aged 22 to 77 years) with TN and ipsilateral CPA tumors. Space-occupying lesions were represented by 29 meningiomas of the petrous apex, 11 epidermoids, 9 vestibular schwannomas, 1 hemangioma, and 1 cavernoma.

RESULTS

Intraoperatively, we identified 6 types of the anatomical relationships among the TNR, tumors, and CPA vessels: type I - the TNR is completely surrounded by the tumor (4 epidermoids); type II - the tumor compresses and displaces the TNR (21 meningiomas, 4 schwannomas, and 6 epidermoids); type III - the tumor occurs inside the TNR (1 cavernoma); type IV - the tumor together with the vessel compresses the TNR (3 meningiomas and 1 epidermoid); type V - the tumor displaces the TNR towards the vessel (5 meningiomas and 5 schwannomas); type VI - the tumor does not contact the TNR that is compressed by the vessel (1 hemangioma). Preoperative MRI and intraoperative findings revealed compression and deformity of the brain stem at the TNR entry level in all but two patients. Vascular compression of the TNR (usually by the superior cerebellar artery) was found in 15 of 51 patients. Microvascular decompression (MVD) was performed using various techniques: interposition of implants between vessels and the TNR, transposition of the compressing vessels from the TNR, or transposition of the nerve root. In all patients, except 1, pain syndrome regressed immediately after tumor removal and MVD. In 1 case, the pain syndrome did not regress after total removal of epidermoid and MVD, and TN was resolved by percutaneous radiofrequency rhizotomy. Long-term postoperative follow-up results showed complete elimination of TN in all cases; there were no persistent neurological complications and postoperative mortality.

CONCLUSION

TN may result from direct compression and deformation of the TNR and brain stem by CPA tumors. In some cases, the cause of TN is combined compression of the TNR by the tumor and vessels. Assessment of the neurovascular relationships requires detailed examination of the entire TNR after tumor removal. In the case of vascular compression of the TNR, various MVD techniques can be used for treatment of TN.

Hemifacial Spasm as Rare Clinical Presentation of Vestibular Schwannomas

OBJECTIVE

Although classical hemifacial spasm (HFS) has been attributed to an atraumatic pulsatile vascular compression around the root exit zone (REZ) of the facial nerve, rare tumor-related HFS associated with meningiomas, epidermoid tumors, lipomas, and schwannomas in the cerebellopontine angle have been reported. The exact mechanism and the necessity of microvascular decompression for tumor-induced HFS is not clear, especially for vestibular schwannomas.

METHODS

We retrospectively analyzed 10 patients with vestibular schwannomas out of 5218 cases of hemifacial spasm between 2004 and 2014.

RESULTS

Hemifacial spasm occurred ipsilateral to the vestibular schwannoma in 9 patients and contralateral to the lesion in 1 patient. The mean follow-up period was 86 months (range, 22-140 months). All patients underwent surgery for resection of the vestibular schwannoma. Following the principle of neurovascular compression, offending vessels were found in 7 patients, no offending vessels in 2 patients, and a tumor with the displacement of brain stem contributing to contralateral facial nerve compression in 1 patient. HFS was relieved immediately postoperatively in 9 patients, whereas it improved gradually and then resolved after one month in one patient with a contralateral vestibular schwannoma.

CONCLUSIONS

For HFS induced by vestibular schwannomas in our study, the majority of cases are caused by a combination of tumor and vascular co-compression at the REZ. Surgical intervention resulted in resolution of symptoms. For HFS with ipsilateral vestibular schwannoma, exploration of the facial nerve root for vascular compression should be performed routinely after tumor resection. It is critical to check that no vessel is contact with the entire nerve root.

Trigeminal neuropathy in vestibular schwannoma: a treatment algorithm to avoid long-term morbidity

BACKGROUND

Trigeminal neuropathy (TGN) can occur as a presenting feature of vestibular schwannoma (VS) or as an adverse effect of radiosurgery. This study was designed to evaluate a treatment algorithm for presenting symptoms of TGN in patients with VS, and a new radiosurgery dosimetric tolerance to avoid TGN after treatment. Outcome was measured after microsurgery (MS), stereotactic radiosurgery (SRS), hypofractionated stereotactic radiotherapy (HSRT), and fractionated radiotherapy (FRT).

METHODS

A prospectively held VS database was retrospectively analysed from 2011 to 2016 at a tertiary university hospital. All patients who underwent MS from 2011 and all patients who underwent radiotherapy (SRS, HSRT, FRT) from 2015 were studied. Patients on surveillance and neurofibromatosis type 2 patients were not included. Patient demographic data, tumour characteristics, presenting symptoms, and post-treatment outcomes were analysed.

RESULTS

Eighty-eight patients were included in the study (43 microsurgery, 45 radiotherapy). Twenty-seven (31%) patients presented with TGN symptoms. The median age of patients included was 56.5 (range 6-72 years), with a median follow-up for MS and SRS of 38 and 20 months, respectively (range 10-80 months). All 27 patients with TGN were offered MS as per protocol. Three patients declined, or were not fit for surgery, and received FRT. Complete resolution of TGN symptoms was achieved in all 24 patients who underwent MS and 33% (1/3) of patients with FRT. Eleven patients experienced transient post-operative complications (pseudomeningocele (6), meningitis (3), venous sinus thrombosis, cerebellar haemorrhagic contusion, and posterior fossa haematoma). Of the 45 patients in the radiotherapy cohort, 36 were suitable for SRS, of which 30 patients who met the dose-volume constraints for trigeminal nerve underwent single-fraction SRS and 6 patients who did not meet the constraints received HSRT. Nine patients (20%) received FRT including three patients with pre-treatment TGN. None of the patients developed new TGN symptoms following SRS or HSRT.

CONCLUSIONS

Our algorithm to select the optimal treatment modality appears to achieve comparable or better long-term outcome. Microsurgical resection in our cohort resulted in complete resolution of symptoms in all patients. None of our SRS- or HSRT-treated patients developed TGN during the follow-up period. The adherence to strict trigeminal nerve dose-volume constraints for SRS remains critical to minimise TGN post treatment. Fractionated radiotherapy is an alternative for patients who refuse surgery or those who are unfit for surgery.

Trigeminal Neuralgia Secondary to Osteoid Osteoma of the Petrous Bone: Report of 4 Cases and Brief Review of Literature

OBJECTIVE

To retrospectively analyze clinical data of 4 patients with trigeminal neuralgia (TN) secondary to osteoid osteoma (OO) of the petrous bone and discuss treatment for this rare disease.

METHODS

Between January 2008 and December 2016, 4 patients in whom TN secondary to petrous bone OO was diagnosed received surgical treatment in Xuan Wu Hospital of Capital Medical University. We summarized the characteristics and treatments of this rare disease through retrospective review of the clinical information, imaging features, surgical details, and follow-up outcomes of the 4 patients.

RESULTS

Among the 4 patients, 2 were men; mean age was 39.3 ± 12.3 years (range, 26-52 years). All patients presented with symptoms of typical TN. Preoperative bone window computed tomography scan of the brain showed a regular bony lesion located at the petrous bone, contacting the trigeminal nerve. All patients experienced total relief of symptoms after surgical resection of the lesion by retrosigmoid sinus approach. During a mean follow-up of 14.2 months (range, 7-23 months), no preoperative symptoms recurred.

CONCLUSIONS

TN secondary to petrous bone OO is extremely uncommon. Surgical decompression is an effective treatment for patients with petrous bone OO and associated TN.

Trigeminal neuralgia and neuropathy in large sporadic vestibular schwannomas

OBJECTIVE

The aim of this study was to evaluate the incidence, presentation, and treatment outcomes of trigeminal nerve–mediated symptoms secondary to large vestibular schwannomas (VSs) with trigeminal nerve contact. Specifically, the symptomatic results of pain, paresthesias, and numbness after microsurgical resection or stereotactic radiosurgery (SRS) were examined.

METHODS

The authors conducted a retrospective review of a database for concomitant diagnosis of trigeminal neuralgia (TN) or trigeminal neuropathy and VS between 1994 and 2014 at a tertiary academic center. All patients with VS with TN or neuropathy were included, with the exception of those patients with neurofibromatosis Type 2 and patients who elected observation. Patient demographic data, symptom evolution, and treatment outcomes were collected. Population data were summarized, and outcome comparisons between microsurgery and SRS were analyzed at last follow-up.

RESULTS

Sixty (2.2%) of 2771 total patients who had large VSs and either TN or neuropathy symptoms met inclusion criteria. The average age of trigeminal symptom onset was 53.6 years (range 24–79 years), the average age at VS diagnosis was 54.4 years (range 25–79 years), and the average follow-up for the microsurgery and SRS groups was 30 and 59 months, respectively (range 3–132 months). Of these patients, 50 (83%) had facial numbness, 16 (27%) had TN pain, and 13 (22%) had paresthesias (i.e., burning or tingling). Subsequently, 50 (83%) patients underwent resection and 10 (17%) patients received SRS.

Treatment of VS with SRS did not improve trigeminal symptoms in any patient. This included 2 subjects with unimproved facial numbness and 4 patients with worsened numbness. Similarly, SRS worsened TN pain and paresthesias in 5 patients and failed to improve pain in 2 additional patients. The Barrow Neurological Institute neuralgia and hypesthesia scale scores were significantly worse for patients undergoing SRS compared with microsurgery.

Resection alleviated facial numbness in 22 (50%) patients, paresthesias in 5 (42%) patients, and TN in 7 (70%) patients. In several patients, surgery was not successful in relieving facial numbness, which failed to improve in 17 (39%) cases and became worse in 5 (11%) cases. Also, surgery did not change the intensity of facial paresthesias or neuralgia in 6 (50%) and 3 (25%) patients, respectively. Microsurgery exacerbated facial paresthesias in 1 (8%) patient but, notably, did not aggravate TN in any patient.

CONCLUSIONS

Overall, resection of large VSs provided improved outcomes for patients with concomitant TN, facial paresthesia, and numbness compared with SRS. However, caution should be used when counseling surgical candidates because a number of patients did not experience improvement. This was especially true in patients with preoperative facial numbness and paresthesias, who frequently reported that these symptoms were unchanged following surgery.

Trigeminal Nerve Deficit in Large and Compressive Acoustic Neuromas and Its Correlation with MRI Findings

Objectives

Evaluate the prevalence of preoperative trigeminal nerve deficit in large/compressive acoustic neuromas and try to find a correlation between pre/postoperative magnetic resonance imaging (MRI) findings and pre/postoperative trigeminal nerve deficit.

Study Design

Case series with chart review.

Setting

University medical center.

Subjects and Methods

Retrospective study (1994-2009) including patients with stage 4 or 5 acoustic neuromas (Zini-Magnan classification). All patients underwent surgical resection. Pre- and postoperative trigeminal symptoms were sought. Imaging criteria were sought on pre- and 3-month postoperative MRI scans. Pearson χ2 statistical test was used.

Results

Fifty-three patients (27 females, mean 51 years) were operated on. Preoperatively, 3 patients (5.7%) had trigeminal neuralgia, 1 (1.9%) trigeminal anesthesia, and 28 (52.8%) trigeminal hypoesthesia. Sixteen patients (30.2%) had no corneal reflex (ophthalmic branch); keratitis occurred in 1 patient (1.9%). Postoperatively, 2 patients (3.8%) had trigeminal neuralgia, 1 (1.9%) trigeminal anesthesia, and 24 (45.3%) trigeminal hypoesthesia. Twenty-six patients (49%) had no corneal reflex; keratitis occurred in 11 patients (20.7%). Preoperative trigeminal hypoesthesia was statistically correlated with impaction of the tumor on cerebellar peduncles on preoperative MRI. Postoperative trigeminal hypoesthesia was statistically correlated with nonvisibility of the trigeminal nerve on postoperative MRI.

Conclusion

In large/compressive acoustic neuromas, trigeminal nerve deficit has to be sought to avoid corneal complications in particular. Trigeminal hypoesthesia occurs preoperatively in about half of the cases. It remains relatively stable after tumor removal, but there appears to be an increased rate of absent corneal reflex and keratitis postoperatively. We were able to correlate pre/postoperative trigeminal hypoesthesia with pre/postoperative MRI findings.

Secondary trigeminal neuralgia in cerebellopontine angle tumors

The analysis of the treatment results in patients with cerebellopontine angle (CPA) tumors, manifested as trigeminal neuralgia (TN). During the 10-year period from 1998 to 2008, 14 patients with verified CPA tumors that had the typical manifestations of TN were operated on at our hospital (5.8% from all patients with TN who underwent surgery). In nine cases the epidermoid was identified; three patients had meningioma, one patient had acoustic neurinoma, and one patient had lipoma. The follow-up of all patients lasted at least 12 months. The intraoperative assessment identified the three variants of relationship between the tumors and neurovascular structures: (1) tumor grows around the trigeminal nerve; (2) the tumor causes compression and displacement of the trigeminal nerve; and (3) tumor presses the arterial vessel to the trigeminal nerve by moving the vessel or nerve. For six patients, with removal of tumor a microvascular decompression of the trigeminal nerve was performed. Complete pain relief was achieved in 12 patients (86%). TN is an expectative symptom of CPA tumors. The most frequent cause of secondary TN of CPA tumors is epidermoid. All patients with manifestations of TN should undergo the magnetic resonance imaging for early diagnosis of CPA tumor.

CEREBELLOPONTINE ANGLE ARACHNOID CYST: A CASE OF HEMIFACIAL SPASM CAUSED BY AN ORGANIC LESION OTHER THAN NEUROVASCULAR COMPRESSION

OBJECTIVE

A rare case of cerebellopontine angle arachnoid cyst manifesting as hemifacial spasm (HFS) is reported. The patient is a 42-year-old woman with 10-month history of left HFS. A preoperative magnetic resonance imaging scan showed a well-demarcated area, hypointense on T1-weighted imaging and hyperintense on T2-weighted imaging, in the left cerebellopontine angle, without contrast enhancement, resembling an arachnoid cyst.

METHODS

The cyst was excised with microneurosurgical technique and the facial, vestibular, and acoustic nerves were completely decompressed from the arachnoid wall.

RESULTS

The postoperative course was uneventful, and the left HFS disappeared immediately. Histologically, the cyst wall was a typical arachnoidal membrane. Ten months after surgery, the patient is symptom free.

CONCLUSION

It is well-known that in approximately 10% of cases, trigeminal neuralgia can be caused by a space-occupying mass. However, the fact that HFS can also be caused by organic lesions as well as neurovascular compression is less well-known. Although the occurrence of tumor compression causing HFS has been previously recognized, cerebellopontine angle cysts have very rarely been described. The observation of a patient with a cerebellopontine angle arachnoid cyst causing HFS prompted us to review the literature relative to HFS caused by an organic lesion rather than neurovascular compression.

Hemifacial spasm caused by pontine glioma: case report and review of the literature

Hemifacial spasm (HFS) is an involuntary paroxysmal contractions of the facial musculature, caused generally by vascular compression of the seventh cranial nerve at its root exit zone from the brain stem. The case of an adult man harbouring brain stem glioma (BSG) whose only neurological signs were left HFS and mild facial weakness is reported. Radiological and neurophysiological findings are described. No responsible vessel could be identified during surgery, but the causative lesion was found to be an astrocytic tumour encasing the facial nerve at its root exit zone from the brain stem. The rarity of such a condition prompted us to review the literature. Nine cases, including our patient presenting with HFS caused by BSG, are reviewed.

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.

Vestibular schwannoma with contralateral facial pain - case report

BACKGROUND

Vestibular schwannoma (acoustic neuroma) most commonly presents with ipsilateral disturbances of acoustic, vestibular, trigeminal and facial nerves. Presentation of vestibular schwannoma with contralateral facial pain is quite uncommon.

CASE PRESENTATION

Among 156 cases of operated vestibular schwannoma, we found one case with unusual presentation of contralateral hemifacial pain.

CONCLUSION

The presentation of contralateral facial pain in the vestibular schwannoma is rare. It seems that displacement and distortion of the brainstem and compression of the contralateral trigeminal nerve in Meckel's cave by the large mass lesion may lead to this atypical presentation. The best practice in these patients is removal of the tumour, although persistent contralateral pain after operation has been reported.

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.

Microvascular decompression to treat hemifacial spasm: long-term results for a consecutive series of 143 patients

OBJECTIVE

The concept of neurovascular decompression for the treatment of hemifacial spasm is now widely accepted. In this study, we report our long-term results for 145 cases treated with this procedure.

METHODS

The results of 145 microvascular decompressions to treat hemifacial spasm (performed between 1980 and 1998) among 143 patients (62.2% female patients and 37.8% male patients; mean age, 54.5 yr) are presented. The onset of symptoms was typical in 95.9% of cases and atypical in 4.1%. Platysma muscle involvement was observed for 24.5% of patients, with a higher incidence among female patients (74.3%). Patients were monitored with annual questionnaires. Twenty-six patients were lost to follow-up monitoring, and 117 are still undergoing follow-up monitoring, with an average period of 9.6 years (range, 1-17.6 yr).

RESULTS

At discharge, 69 patients (59%) were spasm-free and 48 patients (41%) experienced further spasm. At 6 months, the number of spasm-free patients had increased to 108 (92.3%), whereas only 9 patients (7.7%) complained of hemifacial spasm; 44 patients were spasm-free at an average time of 15 weeks. In follow-up examinations (average period, 9.4 yr), 106 patients were spasm-free. Seven patients experienced only temporary relief, with recurrence after 4.5 years. Two patients were spasm-free after 4 or 6 weeks, and the recurrence of spasm was observed 1 year later. Two patients were never completely spasm-free. Among the patients who did not undergo previous surgery elsewhere, only two experienced recurrence.

CONCLUSION

Deafness was the main postoperative complication (8.3%); most of those cases (66%) occurred before the routine use of intraoperative evoked potential monitoring. Analysis of our series demonstrates that this surgical procedure involves very low risk, is well tolerated by elderly patients, is associated with very low recurrence rates, and is a definitive treatment for more than 90% of cases.

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.