Trigeminal involvement in intracranial tumours. Anatomical and clinical observations on 73 patients

Efficacy and safety of Dyna CT-assisted percutaneous balloon compression in the treatment of tumor-related trigeminal neuralgia: A single-center retrospective analysis

BACKGROUND

Percutaneous balloon compression (PBC) has been widely used in the treatment of trigeminal neuralgia (TN). Patients with tumor-related TN are typically treated by tumor resection. However, when craniotomy is not feasible, PBC may serve as a simple and effective method for pain relief. Currently, there is limited literature on the use of this technique in treating patients with tumor-related TN. In this study, we aim to evaluate the efficacy and safety of Dyna CT-assisted PBC in the treatment of tumor-related TN.

METHODS

From January 2018 to December 2023, a total of 19 patients with tumor-related TN underwent Dyna CT-assisted PBC at our institution. The modified Barrow Neurological Institute Pain Intensity Grading Scale and sensory reduction scores were employed to assess treatment outcomes. A retrospective analysis was conducted on the clinical characteristics, surgical efficacy, postoperative complications, and follow-up results of all patients.

RESULTS

Immediate and complete pain relief was observed in 18 patients following PBC, with one patient experiencing delayed recovery. Follow-up periods ranged from 4 to 62 months, revealing only 4 patients with pain recurrence at the last follow-up, and tumor-related TN patients with involvement of Meckel's cave were more prone to recurrence. No severe complications occurred throughout the follow-up period. Although facial numbness was reported in all 15 patients, jaw weakness in 8 patients, and postoperative headache in 7 patients, these symptoms resolved within a short period. There were no statistically significant differences in postoperative facial numbness and jaw weakness between tumor-related TN patients with or without Meckel's cave involvement. However, patients with Meckel's cave involvement were more likely to experience postoperative headaches. Patient satisfaction scores indicated a significant improvement in postoperative quality of life.

CONCLUSION

For patients with tumor-related TN, when craniotomy is not feasible, Dyna CT-assisted PBC proves to be a safe and effective alternative treatment. Additionally, we observed varying postoperative clinical outcomes based on the different sites of tumor compression on the trigeminal nerve. Patients with tumor-related TN not involving Meckel's cave exhibited more enduring clinical efficacy compared to those with Meckel's cave involvement.

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.

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.

Surgical Treatment of Secondary Trigeminal Neuralgia Induced by Cerebellopontine Angle Tumors: A Single-Center Experience

OBJECTIVE

Secondary trigeminal neuralgia (TN) caused by cerebellopontine angle (CPA) tumors are rare, although TN may be a primary manifestation in the neurosurgery department. In this study, we aimed to retrospectively assess patients with CPA tumor-induced TN from a single center.

METHODS

Of 819 consecutive patients with TN treated at our center between 2007 and 2017, 36 with CPA tumor-induced TN were enrolled, and their medical and surgical records were analyzed.

RESULTS

The 36 patients accounted for 4.4% of all patients with TN. A comparison of patients with classic and tumor-induced TN indicated significant intergroup differences in the mean age at surgery (58.94 vs. 49.33 years, P = 0.000), the mean age at onset of TN (52.01 vs. 38.04 years), and affected side (298/485 vs. 22/14 in left/right, P = 0.006); no such difference was noted in the sex ratio (0.598 vs. 0.385, P = 0.214). The rates of excellent, good, and fair clinical outcomes were 80.56%, 13.89%, and 2.78%, respectively. The offending vessels found during surgery included the superior and anterior inferior cerebellar arteries in 3 and 4 cases, respectively. Postoperative complications included aseptic meningitis (1 case), facial numbness (2 cases), hearing disturbance (3 cases), facial palsy (4 cases), hemorrhage (1 case), and diplopia (2 cases).

CONCLUSIONS

Secondary TN caused by CPA tumors is not as frequent as classic TN. Compared with classic TN, tumor-induced TN is characterized by symptom onset and surgery at a younger age. Direct compression rather than chemical irritation is the cause of secondary TN.

Neuroanatomical Determinants of Secondary Trigeminal Neuralgia: Application of 7T Ultra-High-Field Multimodal Magnetic Resonance Imaging

BACKGROUND

Seven-Tesla (7T) magnetic resonance imaging (MRI) has demonstrated value for evaluating a variety of intracranial diseases. However, its utility in trigeminal neuralgia has received limited attention. The authors of the present study applied ultra-high field multimodal MRI to two representative patients with secondary trigeminal neuralgia due to epidermoid tumors to illustrate the possible clinical and surgical advantages of 7T compared with standard clinical strength imaging. Techniques included co-registration of multiple 7T sequences to optimize the detection of potential concurrent neurovascular and neoplasm-derived compression.

METHODS

7T MRI studies were performed using a whole body scanner. Two- and three-dimensional renderings of potential neurovascular conflict were created by co-registering time-of-flight angiography and T2-weighted turbo spin echo images in MATLAB and GE software. Detailed comparisons of the various field strength images were provided by a collaborating neuroradiologist (B.D.).

RESULTS

7T MRI clearly illustrated minute tumor-adjacent vasculature. In contrast, conventional, low-field imaging did not consistently provide adequate details to distinguish cerebrospinal fluid pulsatility from vessels. The tumor margins, although distinct from the trigeminal nerve fibers at 7T, blended with those of the surrounding structures at 3T. Two- and three-dimensional co-registration of time-of-flight angiography with T2-weighted MRI suggested that delicate, intervening vasculature may have contributed to these illustrative patients' symptomatology.

CONCLUSIONS

7T provided superior visualization of vital landmarks and subtle nerve and vessel features. Co-registration of various advanced 7T modalities may help to resolve complex disease etiologies. Future studies should explore the extent to which this dual etiology might persist across tumor types and utilize diffusion-based techniques to quantify what microstructural differences might exist between patients with trigeminal neuralgia from varying etiologies.

[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.

Radiosurgery for Secondary Trigeminal Neuralgia: Revisiting the Treatment Paradigm

BACKGROUND

The mechanisms by which surgery and radiation elicit pain relief in trigeminal neuralgia (TN) secondary to mass lesions vary widely. We aimed to evaluate the outcomes of radiation to the nerve rather than to the lesion in the treatment of secondary TN.

METHODS

We retrospectively reviewed all patients who underwent radiation at the University of California, Los Angeles for TN secondary to tumors. The Barrow Neurological Institute (BNI) pain score was used to evaluate pain outcomes.

RESULTS

Twelve patients were identified; 4 were male and 8 were female. Their mean age at treatment was 59.8 years (range, 47.7-84.7 years). Tumor pathologies included meningioma (n = 8), squamous cell carcinoma (n = 2), vestibular schwannoma (n = 1), and hemangiopericytoma (n = 1). No patient suffered from multiple sclerosis. Ten patients underwent initial radiation targeting their tumors-radiosurgery in 3 and fractionated radiation therapy in 7 others. Only 6 among these 10 experienced at least partial relief, which lasted a mean 6 months. Radiosurgery targeting the trigeminal nerve was eventually performed. Overall, 10 of 12 (83.3%) patients experienced good initial pain relief, complete in 6 (50%) patients. Pain recurred in 6 (60%) patients, at a mean 41 months after radiosurgery to the trigeminal nerve. Three patients experienced facial sensory dysfunction postprocedurally at a mean follow-up duration of 57 months.

CONCLUSION

In contrast to tumor radiation, radiosurgery to the trigeminal nerve root resulted in reasonable and longer pain reduction, on par with the literature regarding surgical resection, with low risk of additional complications.

Rhabdomyomatous mesenchymal hamartoma of the face causing trigeminal neuralgia

BACKGROUND

Rhabdomyomatous mesenchymal hamartoma (RMH) is a benign, potentially pigmented lesion that occurs in the head and neck region. It generally consists of haphazardly arranged skeletal muscle with adipose tissue, blood vessels, collagen and nerve fibers and is largely asymptomatic. Trigeminal neuralgia is pain due to compression of the trigeminal nerve. TN may be idiopathic or associated with lesion-mediated compression.

CASE REPORT

We describe the case of a 14-year-old female presenting with trigeminal neuralgia (TN) associated with RMH. On initial consultation, the patient presented with a history of right-sided lower facial swelling, numbness, and pain. Evaluation by various specialists confirmed TN. Surgical resection of the lesion resolved the condition and pathology confirmed RMH.

CONCLUSIONS

This is the first case report demonstrating RMH-mediated TN. Surgical resection of the RMH is a safe management approach for this diagnosis.

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.

Evaluation of magnetic resonance imaging criteria for Meckel's cave lesion: logistic regression analysis and correlation with surgical findings

OBJECTIVE

Our aim was to investigate the statistical preoperative diagnostic criteria of lesions of Meckel's cave (MC) on MRI.

MATERIALS AND METHODS

We retrospectively reviewed the MR images with MC lesions in 34 patients. The MR signs were compared with histopathologic and surgical findings in all lesions. Odds ratio values and the confidence intervals of the MRI diagnostic criteria were evaluated by univariate logistic regression.

RESULTS

The following three signs of MC on post-contrast T1WI of MRI have been found to represent the most valuable criterion for determination of MC lesion: (1) contrast enhancement, (2) bulging of lateral wall, and (3) the absence of normal MC, with odds ratios of 362.67 (P<.001), 40.38 (P = .001), and 40.38 (P = .001) individually.

CONCLUSION

Contrast enhancement on post-contrast T1WI is the most sensitive MR sign for demonstrating the presence of MC lesion.

Trigeminal neuralgia as the initial manifestation of temporal glioma: Report of three cases and a review of the literature

BACKGROUND

It is almost an accepted scenario that trigeminal neuralgia (TN) occurs when there is a kind of vascular compression on the root entry zone of trigeminal nerve at pons. There are occasional reports about trigeminal neuralgia as the presenting sign of intracranial tumors but temporal glioma has rarely been included in the list.

CASE DESCRIPTION

We report three cases of temporal lobe glioma which presented with trigeminal neuralgia as the initial manifestation and review the relevant literature briefly. The patients were 19-, 20-, and 31-year-old males who presented with partially controlled TN. The tumor mass could be detected in paraclinical evaluations when the usual modalities of therapy for facial pain in our community were not effective. Excisional surgery led in full pain control in all the cases. Two of the patients died because of tumor recurrence after a year and the other one is being treated by adjuvants.

CONCLUSION

We add these types of intracranial tumors to the list of the etiologies for TN and the possible mechanisms for the initiation of pain in these types of intracranial tumors are discussed.

Epidermoid tumors in the cerebellopontine angle presenting with trigeminal neuralgia

OBJECTIVE

The purpose of this study is to evaluate the clinical characteristics and surgical outcome of cerebellopontine angle (CPA) epidermoids presenting with trigeminal neuralgia.

METHODS

Between 1996 and 2004, 10 patients with typical symptoms of trigeminal neuralgia were found to have cerebellopontine angle epidermoids and treated surgically at our hospital. We retrospectively analyzed the clinico-radiological records of the patients.

RESULTS

Total resection was done in 6 patients (60%). Surgical removal of tumor and microvascular decompression of the trigeminal nerve were performed simultaneously in one case. One patient died due to postoperative aseptic meningitis. The others showed total relief from pain. During follow-up, no patients experienced recurrence of their trigeminal neuralgia (TN).

CONCLUSION

The clinical features of TN from CPA epidermoids are characterized by symptom onset at a younger age compared to TN from vascular causes. In addition to removal of the tumor, the possibility of vascular compression at the root entry zone of the trigeminal nerve should be kept in mind. If it exists, a microvascular decompression (MVD) should be performed. Recurrence of tumor is rare in both total and subtotal removal cases, but long-term follow-up is required.

Orofacial pain in cancer: part II--clinical perspectives and management

Cancer-associated pain is extremely common and is associated with significant physical and psychological suffering. Unfortunately, pain associated with cancer or its treatment is frequently under-treated, probably due to several factors, including phobia of opioids, under-reporting by patients, and under-diagnosis by healthcare workers. The most common etiology of cancer pain is local tumor invasion (primary or metastatic), involving inflammatory and neuropathic mechanisms; these have been reviewed in Part I. As malignant disease advances, pain usually becomes more frequent and more intense. Additional expressions of orofacial cancer pain include distant tumor effects, involving paraneoplastic mechanisms. Pain secondary to cancer therapy varies with the treatment modalities used: Chemo-radiotherapy protocols are typically associated with painful mucositis and neurotoxicity. Surgical therapies often result in nerve and tissue damage, leading, in the long term, to myofascial and neuropathic pain syndromes. In the present article, we review the clinical presentation of cancer-associated orofacial pain at various stages: initial diagnosis, during therapy (chemo-, radiotherapy, surgery), and in the post-therapy period. As a presenting symptom of orofacial cancer, pain is often of low intensity and diagnostically unreliable. Diagnosis, treatment, and prevention of pain in cancer require knowledge of the presenting characteristics, factors, and mechanisms involved.

Cerebellopontine angle epidermoids presenting with trigeminal neuralgia

We studied the clinical characteristics of cerebellopontine angle (CPA) epidermoids presenting with trigeminal neuralgia (TN). Twenty-four patients were analyzed retrospectively and the literature reviewed with regard to clinical manifestation, imaging features, surgical procedures and prognosis. TN may be the initial symptom of CPA epidermoid, particularly in young patients. Epidermoids are characteristically hypodense nonenhancing lesions on CT scans, while on MRI they exhibit long T1 and T2 relaxation times. Although complete removal is ideal in the surgical management of CPA epidermoid, proximity to cranial nerves and the brain stem may pose technical difficulties in complete resection. In addition to complete resection of the tumour, arterial compression at the root entry zone (REZ) of the trigeminal nerve should be sought, and if found, a microvascular decompression (MVD) should be performed. Cranial nerve dysfunction and aseptic meningitis are the most common operative complications.

Cerebellopontine angle epidermoids presenting with cranial nerve hyperactive dysfunction: pathogenesis and long-term surgical results in 30 patients

OBJECTIVE

To provide the characteristics and long-term surgical results of patients who present with cerebellopontine angle epidermoids and trigeminal neuralgia (TN) or hemifacial spasm.

METHODS

A total of 30 patients (23 women, 7 men) who presented with cerebellopontine angle epidermoids and TN (28 patients) or hemifacial spasm (2 patients) between 1982 and 1995 were reviewed, with emphasis being placed on the clinical manifestations, the mechanisms of symptom development, the long-term follow-up results, and the anatomic relationship between the tumor and the surrounding neurovascular structures.

RESULTS

The average age of the patients was 37.8 years at symptom onset and 49.3 years at the time of the operation. The tumor-nerve relationships were classified into four types: complete encasement of the nerve by the tumor, compression and distortion of the nerve by the tumor, compression of the nerve by an artery located on the opposite side of the unilateral tumor, and compression of the nerve by an artery on the same side of the tumor. Total resection was achieved in 17 patients (56.7%). Microvascular decompression of the respective cranial nerve was achieved in nine cases of direct arterial compression in addition to tumor removal. The symptom was relieved completely in all cases. In an average follow-up period of 11.5 years, three patients developed recurrent symptoms: two experienced tumor regrowth, and one had arachnoid adhesion.

CONCLUSION

Hyperactive dysfunction of the cranial nerves, especially TN, may be the initial and only symptom that patients with cerebellopontine angle epidermoids experience. The occurrence of TN at a younger age was characteristic of TN patients with epidermoids, in contrast to patients with TN due to a vascular cause. The symptom is elicited by compression of the nerve by the tumor per se, by an artery that is displaced to the nerve, or by both. Careful resection of the tumor, whose capsule occasionally is strongly adherent to the neurovascular structures, is necessary, and microvascular decompression to straighten the neuraxis should be performed in some cases to achieve a complete, permanent cure of symptoms with a low rate of recurrence.

Long-term outcome after gamma knife surgery for secondary trigeminal neuralgia

OBJECT

This study was directed to evaluate the potential role of gamma knife surgery (GKS) in the treatment of secondary trigeminal neuralgia (TN). The authors have identified three anatomicoclinical types of secondary TN requiring different radiosurgical approaches.

METHODS

Pain control was retrospectively analyzed in a population of patients harboring tumors of the middle or posterior fossa that involved the trigeminal nerve pathway. This series included 53 patients (39 women and 14 men) treated using GKS between July 1992 and June 1997. The median follow-up period was 55 months. Treatment strategies differed according to lesion type, topography, and size, as well as visibility of the fifth cranial nerve in the prepontine cistern. Three different treatment groups were established. When the primary goal was treatment of the lesion (Group IV, 46 patients) we obtained pain cessation in 79.5% of cases. In some patients in whom GKS was not indicated for treatment of the lesion, TN was treated by targeting the fifth nerve directly in the prepontine cistern if visible (Group II, three patients) or in the part of the lesion including this nerve if the nerve root could not be identified (Group III, four patients). No deaths and no radiosurgically induced adverse effects were observed, but in two cases there was slight hypesthesia (Group IV). The neuropathic component of the facial pain appeared to be poorly sensitive to radiosurgery. At the last follow-up examination, six patients (13.3%) exhibited recurrent pain, which was complete in four cases (8.8%) and partial in two (4.4%).

CONCLUSIONS

The results of GKS regarding facial pain control are very similar to those achieved by microsurgery according to series published in the literature. Nevertheless, the low rate of morbidity and the greater comfort afforded the patient render GKS safer and thus more attractive.

Long-term outcome after operation for trigeminal neuralgia in patients with posterior fossa tumors

During a 20-year period, 26 patients with typical symptoms of trigeminal neuralgia were found to have posterior fossa tumors at operation. These cases included 14 meningiomas, eight acoustic neurinomas, two epidermoid tumors, one angiolipoma, and one ependymoma. The median patient age was 60 years and 69% of the patients were women. Sixty-five percent of the symptoms were left sided. The median preoperative duration of symptoms was 5 years. The distribution of pain among the three divisions of the trigeminal nerve was similar to that found in patients with trigeminal neuralgia who did not have tumors; however, more divisions tended to be involved in the tumor patients. The mean postoperative follow-up period was 9 years. At operation, the root entry zone of the trigeminal nerve was examined for vascular cross-compression in 21 patients. Vessels compressing the nerve at the root entry zone were observed in all patients examined. Postoperative pain relief was frequent and long lasting. Using Kaplan-Meier methods the authors estimated excellent relief in 81% of the patients 10 years postoperatively, with partial relief in an additional 4%.

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.