Operative findings in cases of trigeminal neuralgia without vascular compression: proposal of a different mechanism

miRNA contributes to neuropathic pains

Neuropathic pain (NP) is a kind of chronic pain caused by direct injury to the peripheral or central nervous system (CNS). microRNAs (miRNAs) are small noncoding RNAs that mostly interact with the 3 untranslated region of messenger RNAs (mRNAs) to regulate the expression of multiple genes. NP is characterized by changes in the expression of receptors and mediators, and there is evidence that miRNAs may contribute to some of these alterations. In this review, we aimed to fully comprehend the connection between NP and miRNA; and also, to establish a link between neurology, biology, and dentistry. Studies have shown that targeting miRNAs may be an effective therapeutic strategy for the treatment of chronic pain and potential target for the prevention of NP.

The Key to a Successful PBC in Treatment of Trigeminal Neuralgia

As a minimally invasive treatment of trigeminal neuralgia, percutaneous balloon compression (PBC) has become increasingly popular worldwide. Because it is simple and straightforward, it does not need a complicated apparatus only a fluoroscope plus an operator's experience. Therefore, the surgical technique seems to be essential and worth further addressing. The paper stresses that the target of PBC should be the semilunar ganglion (the soma of neurons) rather than the rootlets (axons) because the latter is renewable. To obtain a sufficient pressure against the ganglion, Meckel's cave should be covered utterly by an inflating balloon, which fluoroscopically appears in a pear shape. To attain a proper balloon position, it is suggested to make a tunnel with a blunt stylet in a proper penetrative angle before inserting a soft catheter. Too large a pear is unnecessary, hence injecting should be stopped when growth becomes apparently slow. To avoid an unacceptable postoperative paresthesia, a prolonged compression is not encouraged.

Narrow ovale foramina may be involved in the development of primary trigeminal neuralgia

Background

The etiology of primary trigeminal neuralgia remains unclear and is worthy of further study; In this study, the morphometric characteristics of ovale foramina between various groups were compared and analyzed to explore the novel cause of primary trigeminal neuralgia.

Methods

High-resolution three-dimensional reconstruction images from head computed tomography of 109 patients with primary trigeminal neuralgia affecting the third branch of the trigeminal nerve and 46 healthy controls were retrospectively reviewed. Among the 109 primary trigeminal neuralgia patients, 79 patients with apparent neurovascular compression (not simply contact) demonstrated on MRI or during surgery were divided into the classical trigeminal neuralgia group and 30 patients with MRI showing no significant abnormalities were divided into idiopathic trigeminal neuralgia group. The morphometric parameters including the area, width and length of ovale foramina were examined through the use of radiologic methods.

Results

In this study, the average minimum area, width and length of 79 ovale foramina on the affected and unaffected sides in the classical trigeminal neuralgia group were 21.83 ± 8.45, 21.94 ± 7.93 mm², 2.32 ± 0.91, 2.58 ± 0.81, 5.32 ± 1.29, and 5.26 ± 1.21 mm, respectively. No significant difference in these parameters was observed (p > 0.05). However, in the idiopathic trigeminal neuralgia group, the average minimum area, width and length of 30 ovale foramina were 21.33 ± 8.21, 22.85 ± 8.36 mm², 2.25 ± 0.90, 2.79 ± 0.96, 5.20 ± 1.27, and 5.28 ± 1.19 mm, respectively. The width on the symptomatic side was significantly smaller (p = 0.03) than that on the asymptomatic side. No significant difference in area (p = 0.48) or length (p = 0.79) was observed. In addition, when compared with the healthy control group, the area and width of ovale foramina on the symptomatic side in both groups were significantly smaller. No significant difference in length was observed.

Conclusions

By comparing and analyzing the statistical data, it can be inferred that a narrow foramen ovale is associated with primary trigeminal neuralgia, as well as its recurrence after microvascular decompression.

Prognostic factors for long-term outcomes of microvascular decompression in the treatment of glossopharyngeal neuralgia: a retrospective analysis of 97 patients

OBJECTIVE

The authors aimed to investigate predictors of postoperative outcomes of microvascular decompression (MVD) for the treatment of glossopharyngeal neuralgia (GPN).

METHODS

A cohort of 97 patients with medically refractory GPN who underwent MVD at the authors' institution between January 2010 and July 2019 was retrospectively reviewed. Univariate and multivariate regression models were used to identify predictors of long-term outcome in patients after MVD.

RESULTS

Eighty-nine patients (91.8%) reported immediate and complete relief of pain after the procedure. Of the remaining 8 patients (8.2%), 6 achieved partial pain relief and pain gradually diminished within 2 weeks after surgery, and 2 did not experience postoperative pain relief. In univariate Cox regression analysis, venous compression of the glossopharyngeal nerve root entry zone (HR 3.591, 95% CI 1.660-7.767, p = 0.001) and lower degree of neurovascular conflict (HR 2.449, 95% CI 1.177-5.096, p = 0.017) were significantly associated with worse pain-free survival. In multivariate Cox regression analysis, venous compression (HR 8.192, 95% CI 2.960-22.669, p < 0.001) and lower degree of neurovascular conflict (HR 5.450, 95% CI 2.069-14.356, p = 0.001) remained independently associated with worse pain-free survival.

CONCLUSIONS

Venous compression of the glossopharyngeal nerve root entry zone and lower degree of neurovascular conflict were significantly correlated with shorter pain-free survival in patients who underwent MVD for GPN. Microvascular decompression is a safe, feasible, and durable approach with a low complication rate for the treatment of GPN.

MRI Findings in Trigeminal Neuralgia without Neurovascular Compression: Implications of Petrous Ridge and Trigeminal Nerve Angles

Objective

To determine the anatomical characteristics of the petrous ridge and trigeminal nerve in trigeminal neuralgia (TN) without neurovascular compression (NVC).

Materials and Methods

From May 2017 to March 2021, 66 patients (49 female and 17 male; mean age ± standard deviation [SD], 56.8 ± 13.3 years) with TN without NVC and 57 controls (46 female and 11 male; 52.0 ± 15.6 years) were enrolled. The angle of the petrous ridge (APR) and angle of the trigeminal nerve (ATN) were measured using magnetic resonance imaging with a high-resolution three-dimensional T2 sequence. Data on the symptomatic side were compared with those on the asymptomatic side in patients and with the mean measurements of the bilateral sides in controls. Receiver operating characteristic (ROC) analysis was conducted to evaluate the performance of APR and ATN in distinguishing TN patients from controls.

Results

In TN patients without NVC, the mean ± standard deviation (SD) of APR on the symptomatic side (98.40° ± 19.75°) was significantly smaller than that of the asymptomatic side (105.59° ± 22.45°, p = 0.019) and controls (108.44° ± 15.98°, p = 0.003). The mean ATN ± SD on the symptomatic side (144.41° ± 8.92°) was significantly smaller than that of the asymptomatic side (149.67° ± 8.09°, p = 0.003) and controls (150.45° ± 8.48°, p = 0.001). The area under the ROC curve for distinguishing TN patients from controls was 0.673 (95% confidence interval [CI]: 0.579–0.758) for APR and 0.700 (CI: 0.607–0.782) for ATN. The sensitivity and specificity using the diagnostic cutoff yielding the highest Youden index were 81.8% (54/66) and 49.1% (28/57), respectively, for APR (with a cutoff score of 94.30°) and 65.2% (43/66) and 66.7% (38/57), respectively, for ATN (cutoff score, 148.25°).

Conclusion

In patients with TN without NVC, APR and ATN were smaller than those in controls, which may explain the potential cause of TN and provide additional information for diagnosis.

Neurapraxia in patients with trigeminal neuralgia but no identifiable neurovascular conflict during microvascular decompression: a retrospective analysis of 26 cases

Background

Microvascular decompression (MVD) is the first choice in patients with classic trigeminal neuralgia (TGN) that could not be sufficiently controlled by pharmacological treatment. However, neurovascular conflict (NVC) could not be identified during MVD in all patients. To describe the efficacy and safety of treatment with aneurysm clips in these situations.

Methods

A total of 205 patients underwent MVD for classic TGN at our center from January 1, 2015 to December 31, 2019. In patients without identifiable NVC upon dissection of the entire trigeminal nerve root, neurapraxia was performed using a Yasargil temporary titanium aneurysm clip (force: 90 g) for 40 s (or a total of 60 s if the process must be suspended temporarily due to bradycardia or hypertension).

Results

A total of 26 patients (median age: 64 years; 15 women) underwent neurapraxia. Five out of the 26 patients received prior MVD but relapsed. Immediate complete pain relief was achieved in all 26 cases. Within a median follow-up of 3 years (range: 1.0–6.0), recurrence was noted in 3 cases (11.5%). Postoperative complications included hemifacial numbness, herpes labialis, masseter weakness; most were transient and dissipated within 3–6 months.

Conclusions

Neurapraxia using aneurysm clip is safe and effective in patients with classic TGN but no identifiable NVC during MVD. Whether this method could be developed into a standardizable method needs further investigation.

External Neurolysis in Microvascular Decompression for Magnetic Resonance Imaging-Negative Idiopathic Trigeminal Neuralgia

OBJECTIVE

Internal neurolysis has been proposed as an alternative to microvascular decompression in patients with idiopathic trigeminal neuralgia (TN) in whom neurovascular compression is not confirmed by magnetic resonance imaging (MRI). External neurolysis, which straightens and realigns the trigeminal nerve root axis by dissecting the arachnoid membranes around the nerve, was reported 20 years ago in the context of so-called negative exploration when MRI did not confirm the absence of the offending vessel, but is not currently used.

METHODS

External neurolysis was performed in 4 patients with idiopathic TN with typical evoked neuralgic pain despite the absence of suspected offending vessels on MRI. The surgical findings that caused TN were summarized and the outcomes were evaluated using the Barrow Neurological Institute Pain Intensity Scale (BNI-PS).

RESULTS

Tethering and distortion of the nerve root by surrounding arachnoid membranes were commonly found. All 4 patients showed complete pain relief immediately after surgery. During the follow-up period of 26.5 ± 16.92 months (±standard deviation), 3 of 4 patients had no pain (score I, BNI-PS). One patient received a score of IIIa on the BNI-PS assessment. There was no instance of recurrence or side effects associated with the surgery.

CONCLUSIONS

Idiopathic TN can be induced by individual variation of the surrounding inner arachnoid membranes supporting the trigeminal nerve root, and the condition cannot be identified by MRI. Intradural external neurolysis may be considered an effective treatment for MRI-negative idiopathic TN.

Long-Term Retrospective Analysis of Re-do Microvascular Decompression in Patients With Hemifacial Spasm

Objective: To explore the clinical characteristics of patients with persistent or recurrent hemifacial spasm (HFS) and the experience of microvascular decompression (MVD) in the treatment of such patients to accumulate additional clinical evidence for optimal treatment protocols.

Methods: We retrospectively analyzed the clinical data, surgical methods and treatment efficacies of 176 patients with persistent or recurrent HFS from January 2009 to January 2018.

Results: Missing compression zones was the main reason for symptom persistence (87.50%) or recurrence (71.50%) after MVD treatment of HFS. We divided the surgical area into three zones. Most persistent or recurrent cases had decompression only in the root exit zone (REZ) (Zone 1) but missed the ventrolateral pons-involved area (Zone 2) or the bulbopontine sulcus-involved area (Zone 3) in the first MVD. Too much use of Teflon (12.50%), arachnoid adhesions (5.60%) and Teflon granulomas (10.40%) can also cause a recurrence. The difference between preoperative and postoperative Cohen scores was statistically significant in persistent or recurrent HFS patients (p<0.05). The postoperative follow-up time ranged from 36 to 108 months (71.75 ± 22.77).

Conclusions: MVD should be performed in the compression site, which is mostly located at the brainstem/facial REZ. Intraoperative exploration should be conducted in accordance with the abovementioned zones to effectively avoid missing offending vessels. Re-do MVD is effective in patients with persistent or recurrent HFS.

Trigeminal Neuralgia Caused by Dural Arteriovenous Fistula of the Transverse-Sigmoid Sinus without Vessel Compression at Root Entry Zone

Objective

The vessel compression at the root entry zone (REZ) of trigeminal nerve is a common cause of trigeminal neuralgia (TN). We report a rare case of TN caused by dural arteriovenous fistula (DAVF) of the transverse-sigmoid sinus without vessel compression at REZ.

Case Presentation

A 45-year-old woman presented with right side tinnitus and was diagnosed as a DAVF of the right transverse-sigmoid sinus (Borden Type I). After that, the facial pain in the right maxillary nerve area appeared and was getting worse. DSA revealed an enlargement of the artery of foramen rotundum (AFR) as one of the feeding arteries. MRI revealed no evidence of vascular compression at REZ. The patient was treated with transarterial embolization (TAE) with Onyx via the branches of the middle meningeal artery (MMA) and occipital artery (OA). The AFR decreased in size and the facial pain was improved. However, the DAVF and the facial pain were recurred. Finally, the DAVF was completely embolized with transvenous embolization (TVE). During 1-year follow-up period, the patient remained free of pain without recurrence.

Conclusion

The compression of the maxillary nerve by the AFR might result in TN, because the pain diminished after shrinkage of the AFR by the endovascular treatment.

Microvascular Decompression for Trigeminal Neuralgia: Experience of a Tertiary Care Center in India and a Brief Review of Literature

Background

Trigeminal neuralgia (TN) is a devastating condition causing significant patient discomfort and morbidity hampering quality of life. Of the many treatment options available, microvascular decompression (MVD) of the trigeminal nerve is widely performed. However, the procedure is not risk-free.

Objective

The study aimed to describe our experience of treating TN via MVD and long-term follow-up of the patients treated by this modality.

Materials and Methods

It is a 5-year retrospective analysis of the database of patients with idiopathic TN treated with MVD at our institute. A total of 106 patients fulfilling the criteria of idiopathic TN by International Classification of Headache Disorders, 3^rd ed.ition and available for follow-up for at least 1-year post-procedure were included in the study.

Results

Of the 106 patients, 58 (54.7%) were female and 48 (45.3%) were male with a mean age of 55 years (range 22-75 years). Vascular compression of the trigeminal nerve was seen in all cases; arterial compression in 82%, both artery and vein 14.5% while unidentified vessels were the culprit in 3.8% of the patients. There were no intra- or post-operative deaths. The best response was achieved at 1 month following the procedure where 85% of the patients achieved excellent outcomes.

Conclusion

In experienced hands, MVD is still a safe and cost-effective modality over a myriad of treatment options available for TN in patients of all ages. The absence of adhesions, indentations, and distortion of the trigeminal nerve are positive predictors of excellent outcomes in the long run.

Trigeminal neuralgia caused by an arachnoid cyst in Meckel's cave: A case report and literature review

Background:

We present a rare case of trigeminal neuralgia (TN) caused by an arachnoid cyst (AC) in Meckel’s cave (MC).

Case Description:

A 35-year-old man presented with facial pain in the left maxillary and mandibular regions. Since the initial magnetic resonance (MR) imaging showed no apparent offending vessels or tumors, the patient was diagnosed with idiopathic TN, for which carbamazepine was initially effective. When his pain worsened, he was referred to our hospital. A slightly asymmetric shape of MC and distorted course of the trigeminal nerve was confirmed on the initial and repeat MR images. His pain was characterized as electric-shock-like pain, which was triggered by touching the face. Under the tentative diagnosis of an AC confined to MC compressing the trigeminal nerve, the exploration of MC through suboccipital craniotomy was performed. Intraoperatively, the AC was identified in the rostral portion of MC. The indentation of the trigeminal nerve was also observed at the orifice of MC, indicating severe compression by the AC. The wall of the AC was fenestrated. The patient’s pain was relieved immediately after surgery. Postoperative MR images showed that the course of the trigeminal nerve was straightened. Although our literature review found five similar cases, the size of the AC was the smallest in our case.

Conclusion:

Although it is rare, the AC confined to MC can cause TN. The findings of this study emphasize the importance of evaluating subtle radiological findings of compression on the trigeminal nerve in cases of TN seemingly without neurovascular compression.

Meckel's Cave and Somatotopy of the Trigeminal Ganglion

BACKGROUND

The anatomy and spatial relationships of the dural sac comprising the Meckel cave (MC) and its ensheathed trigeminal ganglion (TG) are exceedingly intricate and complex. There are conflicting accounts in the literature regarding the dural configuration of the MC around the ganglion and the dual embryology of the MC and TG is still unclear.

METHODS

A combined systematic and narrative literature review was conducted to collate articles addressing MC and TG anatomy, in addition to their embryology, role in tumor spread, somatotopy, and association with trigeminal neuralgia.

RESULTS

Three key anatomic models by Paturet (1964), Lazorthes (1973), and Lang and Ferner (1983) have been put forward to show the arrangement of the MC around the TG. The TG is formed from both neural crest and placodal cells and drags the enveloping dura caudally to form the MC prolongation during development. Both a mediolateral and dorsoventral somatotopic arrangement of neurons exists in the TG, which corresponds to the 3 nerve divisions, of which V2 and V3 are prone to perineural tumor spread along their course.

CONCLUSIONS

Sound knowledge concerning the dural arrangement of the MC and the trigeminal divisions will be invaluable in optimally treating cancers in this region, and understanding TG somatotopy will immensely improve treatment of trigeminal neuralgia in terms of specificity, efficacy, and positive patient outcomes.

Personal experience with microvascular decompression and partial sensory rhizotomy for trigeminal neuralgia

Background

Trigeminal neuralgia (TN) is a severe, paroxysmal pain in the distribution of the fifth cranial nerve. Microvascular decompression (MVD) is the most widely used surgical treatment for TN. We undertook this study to analyze the effects of and complications of MVD and to refine the surgical procedure for treating TN.

Methods

A total of 88 patients underwent for TN underwent surgery at our hospital. Among them, 77 patients underwent MVD alone, and 11 underwent partial sensory rhizotomy (PSR) with or without MVD. The medical records of these patients were retrospectively analyzed for patient characteristics, clinical results, offending vessels, and complications if any.

Results

The mean follow-up duration was 43.2 months (range, 3–216 months). The most common site of pain was V2+V3 territory (n=27), followed by V2 (n=25) and V3 (n=23). The most common offending vessels were the superior cerebellar artery and anterior inferior cerebellar artery in that order. The overall rate of postoperative complications was 46.1%; however, most complications were transient. There were two cases of permanent partial hearing disturbance. In the MVD alone group, the cure rate was 67.5%, and the improvement rate was 26.0%. Among 11 patients who underwent PSR with or without MVD, the cure rate was 50.0%, and the improvement rate was 30.0%.

Conclusion

The clinical results of MVD were satisfactory. Although the outcomes of PSR were not as favorable as those of pure MVD in this study, PSR can be considered in cases where there is no significant vascular compressive lesion or uncertainty of the causative vessel at the surgery.

Characteristics and management of the offending veins in microvascular decompression surgery for trigeminal neuralgia

The optimal technique of microvascular decompression (MVD) for trigeminal neuralgia (TN) caused by venous conflict remains unclear. The objectives of this study are to characterize the offending veins identified during MVD for TN and to evaluate intraoperative technique applied for their management. From 2007 till 2019, 308 MVD surgeries were performed in 288 consecutive patients with TN, and in 58 of them, pure venous conflict was identified. In 44 patients, the offending vein was interrupted, as was done for small veins arising from the cisternal trigeminal nerve (CN V) or its root entry zone (REZ) causing their stretching (19 cases), small veins on the surface of REZ (9 cases), transverse pontine vein (TPV) compressing REZ or distal CN V (12 cases), and superior petrosal vein (SPV) using flow conversion technique (4 cases). In 14 other cases, the offending vein was relocated, as was done for the SPV or the vein of cerebellopontine fissure (8 cases), TPV (3 cases), and the vein of middle cerebellar peduncle (3 cases). Complete pain relief after surgery was noted in 49 patients (84%). No one patient experienced major neurological deterioration. Postoperative facial numbness developed in 14 patients (24%), and in 8 of them, it was permanent. In 14 patients, MRI demonstrated venous infarction of the middle cerebellar peduncle, which was associated with the presence of any (P = 0.0180) and permanent (P = 0.0002) facial numbness. Ten patients experienced pain recurrence. Thus, 39 patients (67%) sustained complete pain relief at the last follow-up (median, 48 months), which was significantly associated with the presence of any (P = 0.0228) and permanent (P = 0.0427) postoperative facial numbness. In conclusion, in cases of TN, small offending veins arising from REZ and/or distal CN V and causing their stretching may be coagulated and cut. In many cases, TPV can be also interrupted safely or considered as collateral way for blood outflow. The main complication of such procedures is facial numbness, which is associated with the venous infarction of middle cerebellar peduncle and long-term complete pain relief.

Trigeminal interfascicular neurolysis (nerve combing) for refractory recurrent neuralgia in multiple sclerosis

In multiple sclerosis (MS) patients, trigeminal neuralgia (TN) represents a challenging syndrome to treat, often refractory to medical therapy and percutaneous techniques. Despite the frequent lack of a neurovascular conflict, the trigeminal nerve’s axons are often damaged, with the myelin sheath permanently degenerated, thus explaining the difficulty in treating TN in MS.

The authors illustrate trigeminal interfascicular neurolysis (the combing technique) to control refractory recurrent TN in MS: the nerve is longitudinally divided along its fibers from the root entry zone, determining good pain relief.

The video can be found here: https://youtu.be/o1XksPW5fMY

Efficacy of microvascular decompression in patients with trigeminal neuralgia with negative neurovascular relationship shown by magnetic resonance tomography

OBJECTIVE

To explore the surgical efficacy of microvascular decompression(MVD) when the recent magnetic resonance tomography angiography(MRA) is unable to determine the relationship between blood vessels and nerves in patients with trigeminal neuralgia(TN).

MATERIALS AND METHODS

The MRI images of 146 patients with TN who underwent MVD from January 2016 to December 2019 were analyzed retrospectively. The relationship between nerves and vessels was categorized as no contact, suspicious contact, and clear contact. Suspicious contact and clear contact were both defined as positive neurovascular relationship, whereas no contact was defined as negative neurovascular relationship. The efficacy of MVD in positive and negative groups was compared.

RESULTS

1. A total of 146 TN patients underwent MVD. Intraoperative examination revealed that out of 146, 143 patients exhibited contacts, including 110 cases with arterial contact, 22 cases with combined arterial and venous contact, and 11 cases with venous contact. Considering the surgical result as a gold standard, the sensitivity of three-dimensional time leap angiography (3D-TOF-MRA) in assessing vascular compression in TN was 74.0 %; and the sensitivity of three-dimensional steady-state precession rapid imaging sequence (3D-FIESTA) in determining vascular compression was 82.2 %. Out of a total of 17 cases demonstrating negative neurovascular relationship by 3D-TOF-MRA together with 3D-FIESTA, 14 cases were found to have vascular contact during the surgery, and the sensitivity was determined to be 88.4 %. 2.Among the 38 patients with a negative neurovascular relationship demonstrated by 3D-TOF, postoperative efficacy was noted as a cure: 30 cases, improved: 5 cases, no effect: 3 cases. 3D-FIESTA showed 26 cases of negative neurovascular relationship, among them, cured: 20 cases, improved: 3 cases, no effect: 3 cases. A total of 17 patients with negative neurovascular relationships were established by 3D-TOF-MRA together with 3D-FIESTA, and the postoperative effects were found to be cure: 13 cases, improvement: 2 cases, and no effect: 2 cases. There was no statistically significant difference between the negative group and the positive group (x² test; p > 0.05).

CONCLUSION

To conclude, 3D-TOF-MRA, together with 3D-FIESTA, can illustrate the large blood vessels surrounding the trigeminal nerve efficiently, and determine whether it is the offending blood vessel. The interpretation would help reproduce the local anatomical spatial structure of the site before surgery, yet it is impossible to assess the peripheral anatomical relationship of the trigeminal nerve cistern comprehensively and accurately. This hints that a perfect prediction of the surgical effect of MVD is not possible at present. Thus, typical symptoms of TN are the most critical indicators for MVD surgery.

The Spectrum of Trigeminal Neuralgia Without Neurovascular Compression

BACKGROUND

In trigeminal neuralgia type 1 (TN1), neurovascular compression (NVC) is often assumed to be the pain initiating mechanism. NVC can be surgically addressed by microvascular decompression (MVD). However, some patients with TN1 present without NVC (WONVC).

OBJECTIVE

To characterize and analyze the clinical spectrum of a TN1 patient population WONVC.

METHODS

A retrospective chart review of patients presenting with TN1 between 2007 and 2017 was performed. Patients who were potential candidates for MVD surgery underwent high-resolution imaging with 3-dimensional (3D) reconstruction to address the presence, or absence, of NVC. Demographic data about the populations with NVC (WNVC) and WONVC were collected.

RESULTS

Of 242 patients with TN1, 32% did not have NVC. Patients WONVC were on average 10.6 yr younger than those WNVC. TN1 onset in patients WONVC was more frequent below 48.7 yr, and the opposite was found in patients WNVC. Compared to patients WNVC, those WONVC were predominantly female (odds ratio 4.8), on average were 4 yr younger at symptom onset (34.7 yr) and 7.8 yr younger at first clinic visit, and had a 3.7 yr shorter symptom duration.

CONCLUSION

Patients presenting with TN1 WONVC were predominantly females in their mid-30s with short symptom duration. In the absence of NVC, this subgroup of TN1 patients has limited surgical options, and potentially a longer condition duration that must be managed medically or surgically. This population WONVC might provide insights into the true pathophysiology of TN1.

Retrosigmoid approach for glycerin rhizotomy in the treatment of trigeminal neuralgia without overt arterial compression: updated case series

OBJECTIVE

Trigeminal neuralgia (TN) is a neuropathic pain disorder characterized by severe, lancinating facial pain that is commonly treated with neuropathic medication, percutaneous rhizotomy, and/or microvascular decompression (MVD). Patients who are not found to have distinct arterial compression during MVD present a management challenge. In 2013, the authors reported on a small case series of such patients in whom glycerin was injected intraoperatively into the cisternal segment of the trigeminal nerve. The objective of the authors' present study was to report their updated experience with this technique to further validate this novel approach.

METHODS

The authors performed a retrospective analysis of data obtained in patients in whom glycerin was directly injected into the inferior third of the cisternal portion of the trigeminal nerve. Seventy-four patients, including 14 patients from the authors' prior study, were identified, and demographic information, intraoperative findings, postoperative course, and complications were recorded. Fisher's exact test, unpaired t-tests, and Kaplan-Meier survival curves using Mantel log-rank test were used to compare the 74 patients with a cohort of 476 patients who received standard MVD by the same surgeon.

RESULTS

The 74 patients who underwent MVD and glycerin injection had an average follow-up of 19.1 ± 18.0 months, and the male/female ratio was 1:2.9. In 33 patients (44.6%), a previous intervention for TN had failed. On average, patients had an improvement in the Barrow Neurological Institute Pain Intensity score from 4.1 ± 0.4 before surgery to 2.1 ± 1.2 after surgery. Pain improvement after the surgery was documented in 95.9% of patients. Thirteen patients (17.6%) developed burning pain following surgery. Five patients developed complications (6.7%), including incisional infection, facial palsy, CSF leak, and hearing deficit, all of which were minor.

CONCLUSIONS

Intraoperative injection of glycerin into the trigeminal nerve is a generally safe and potentially effective treatment for TN when no distinct site of arterial compression is identified during surgery or when decompression of the nerve is deemed to be inadequate.

The efficacy and safety of nerve combing for trigeminal neuralgia without neurovascular compression

OBJECTIVE

The purpose of our study was to review and evaluate the efficacy and safety of nerve combing without neurovascular decompression for trigeminal neuralgia.

METHODS

A retrospective review of 298 patients with trigeminal neuralgia between August 2007 and August 2016 was conducted. The patients were divided into two groups: the A group was treated by nerve combing (34 patients) and the B group received microvascular decompression (264 patients). Surgical outcomes and postoperative complications were compared between the two groups.

RESULTS

Pain was completely relieved in 88.2% of group A patients and 92.8% of group B after surgery. The median duration of follow-up was 60 months (range 10-115 months) in group A and 62 months (range 12-118 months) in group B. 72.7% and 86.4% of cases were completely relieved in groups A and B, respectively. There were no statistically significant differences in the surgical outcomes between the two groups. Almost all patients experienced some degree of numbness or hypesthesia (76.5%). The rate of facial numbness in group A was significantly higher than that in group B.

CONCLUSION

This study demonstrated that nerve combing without neurovascular decompression is a safe and effective treatment for trigeminal neuralgia. However, a majority of patients treated with nerve combing experienced some degree of facial numbness.

Gamma Knife Radiosurgery in Recurrent Trigeminal Neuralgia after Other Procedures

Objectives Trigeminal neuralgia (TN) is undurable paroxysmal pain in the distribution of the fifth cranial nerve. Invasive treatment modalities for TN include microvascular decompression (MVD) and percutaneous procedures, such as, radiofrequency rhizotomy (RFR). Gamma Knife radiosurgery (GKRS) is a considerable option for patients with pain recurrence after an initial procedure. This study was undertaken to analyze the effects of gamma knife radiosurgery in recurrent TN after other procedures. Methods Eleven recurrent TN patients after other procedures underwent GKRS in our hospital from September 2004 to August 2016. Seven patients had previously undergone MVD alone, two underwent MVD with partial sensory rhizotomy (PSR), and two underwent RFR. Mean patient age was 60.5 years. We retrospectively analyzed patient's characteristics, clinical results, sites, and divisions of pain. Outcomes were evaluated using the Visual Analog Scales (VAS) score. Results Right sides were more prevalent than left sides (7:4). The most common distribution of pain was V1 + V2 division (n = 5) following V2 + V3 (n = 3), V2 (n = 2), and V1 + V2 + V3 (n = 1) division. Median GKRS dose was 80 Gy and the mean interval between the prior treatment and GKRS was 74.45 months. The final outcomes of subsequent GKRS were satisfactory in most cases, and at 12 months postoperatively ten patients (90.0%) had a VAS score of ≤ 3. Conclusions In this study, the clinical result of GKRS was satisfactory. Invasive procedures, such as, MVD, RFR are initially effective in TN patients, but GKRS provides a safe and satisfactory treatment modality for those who recurred after prior invasive treatments.

The Tethered Effect of Vestibular Schwannoma Tumor Shrinkage Following Stereotactic Radiosurgery in Secondary Trigeminal Neuralgia

BACKGROUND

Compression of the trigeminal nerve by vessels and tumors causes trigeminal neuralgia. However, a tethering effect, provoking an abnormal root-stretching force, has been previously reported to play a role in trigeminal nerve hyperexcitability. We report 2 patients with vestibular schwannomas treated by stereotactic radiosurgery (SRS) who presented with typical manifestations of trigeminal neuralgia after tumor shrinkage. Furthermore, we discuss the mechanisms of trigeminal neuralgia.

CASE DESCRIPTION

Two patients without a history of trigeminal dysfunction, including trigeminal neuralgia, underwent SRS for vestibular schwannomas. Both patients demonstrated tumor shrinkage after transient tumor expansion following SRS. Neither patient presented with facial pain or dysesthesia at the time of peak tumor volume. However, trigeminal neuralgia occurred after tumor shrinkage. One patient underwent surgery, as the neuralgia was refractory to medical treatment; although the trigeminal nerve was adhered and tethered to the tumor, no neurovascular conflict was identified between the tumor and the nerve. We removed the tumor partially, dissecting between the nerve and the tumor, and relieved the tethered effect. Trigeminal neuralgia was relieved without medication after surgery.

CONCLUSIONS

The present cases demonstrate a tethered effect of tumor shrinkage after SRS, which was considered to play a role in trigeminal neuralgia. Surgical dissection surrounding the nerve root is effective for medically resistant neuralgia, even if the tumor shrinks. Partial tumor removal is adequate in such cases, as the tumor has been controlled by radiosurgery.

Surgical treatment of trigeminal neuralgia with no neurovascular compression: A retrospective study and literature review

The objective of the current study is to summarize the experiences of 360-degree circumferential arachnoid dissection for TN in patients without NVC. Clinical data from 19 TN patients without NVC who underwent 360-degree circumferential arachnoid dissection were retrospectively analyzed. All patients underwent preoperative examinations of three-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) and three-dimensional nuclear magnetic resonance of constructive interference in steady state (3D-CISS) to identify the neurovascular structures around the trigeminal nerve. Surgical outcomes were evaluated based on the Barrow Neurological Institute (BNI) Pain Intensity Scale, and severity of pain was determined using the visual analogue scale (VAS) score. Preoperative imaging showed that no patients had NVC compression. The preoperative BNI pain score was IV among 9 patients and V among other 10 patients. The preoperative VAS score was 7.89 ± 0.658. After the operation, pain disappeared in all 19 patients, and transient facial numbness occurred in 3 patients. During follow-up, pain in 2 of 19 patients (10.5%) recurred at postoperative 20 and 23 months. This study demonstrated that 360-degree circumferential arachnoid dissection is an alternative treatment for trigeminal neuralgia in patients with no neurovascular compression, especially when a thickened arachnoid, angulation, or torsion of the trigeminal nerve root was found during the operation. However, further study is needed to compare the outcomes of different surgical strategies and prove the efficacy of 360-degree circumferential arachnoid dissection in cases without neurovascular compression (NVC).

Absence of neurovascular conflict during microvascular decompression while treating essential trigeminal neuralgia. How to proceed? Systematic review of literature

INTRODUCTION

Neurovascular conflict is the most accepted hypothesis for the cause for trigeminal neuralgia. Microvascular decompression of the trigeminal nerve is the most common surgical treatment for these patients. However, despite advances in diagnostic techniques, neurovascular conflict is sometimes not detected during surgery. The aim of this paper is to systematically review all the options available to best manage this scenario.

RESULTS

Several techniques that could be used during microvascular decompression for trigeminal neuralgia in the absence of neurovascular conflict have been described. The success rates of these techniques, pain recurrence rates and rates of complications are also reported. Finally, we provide suggestions based on our experience.

CONCLUSIONS

There is no gold standard, but several techniques could be successfully used in the absence of neurovascular conflict. The use of destructive techniques, such as PSR, should be held as treatments of last resort.

Nerve Combing for Trigeminal Neuralgia Without Vascular Compression

OBJECTIVE

The aim of this study was to describe and evaluate the long-term clinical outcome of "nerve combing" for trigeminal neuralgia (TN) without vascular compression.

METHODS

Fifteen patients with TN treated with microvascular decompression had no visible vascular compression intraoperatively. All of them underwent trigeminal nerve combing.

RESULTS

The long-term excellent relief was achieved in 73.3% of patients, 2 patients had good outcome, 1 patient experienced obvious partial relief, and the intensity of the residual pain was not severe enough to require medication. Three patients suffered facial numbness postoperatively, but it completely disappeared by 4 months after operation.

CONCLUSION

Nerve combing is an effective method in treating TN without vascular compression; however, further studies should be carried out to explore the possible mechanisms of underlying pain relief.

Flat Posterior Cranial Fossa Affects Outcomes of Microvascular Decompression for Trigeminal Neuralgia

OBJECTIVE

To investigate the prognostic factors for microvascular decompression (MVD) in patients with primary trigeminal neuralgia (TN), with a particular focus on the morphology of the posterior cranial fossa (PCF).

METHODS

The present study investigated 126 surgically treated patients with primary TN with more than 1-year follow-up who underwent high-resolution magnetic resonance imaging between April 2003 and September 2015. We retrospectively reviewed clinical information and operative findings. Outcomes of MVD were also evaluated and patients were classified into "success" and "failure" groups. Furthermore, length, width, and height of the PCF were measured by approximation to an ellipsoid with reference to the anterior commissure-posterior commissure line. These values were compared between groups.

RESULTS

Atypical type 2 TN (P < 0.001) and weak neurovascular compression (P < 0.001) correlated significantly with poor outcomes of MVD for primary TN. In terms of PCF morphology, the failure group showed a flatter PCF than the success group, whereas sex, age, affected side, topography of facial pain, interval between onset and surgery, responsible vessel, location of compression along the nerve, and site of compression around the circumference of the nerve root did not significantly affect outcomes of MVD for primary TN.

CONCLUSIONS

The present study identified type 2 TN, weak neurovascular compression, and flatness of the PCF as predictors of poor prognosis after MVD for primary TN.

Modified Decompression of the Infraorbital Canal to Treat Trigeminal Neuralgia Affecting the Maxillary Branch

PURPOSE

To modify the method of treating trigeminal neuralgia (TN) affecting the maxillary branch and to provide clinical evidence of an etiologic hypothesis of narrowing bone canal compression.

MATERIALS AND METHODS

Forty patients who met the inclusion and exclusion criteria were included, and those with bony compression of the affected infraorbital canal (IOC) were selected by preoperative computer measurement. Modified decompression of the IOC was performed through the maxillary sinus with the assistance of a piezoelectric device and an endoscope. The results of the operation were evaluated.

RESULTS

Fourteen patients (35.00%) had bony compression of the affected IOC. During a mean follow-up period of 29.4 months, 11 patients (78.57%) had complete pain relief (excellent); 1 (7.14%) had moderate relief with carbamazepine administration. The success rate was 85.71% (12 of 14). The postoperative numbness rate was 35.71% (5 of 14).

CONCLUSION

Narrowing of the IOC might be a reason some patients with TN have no intracranial neurovascular compression and have pain localized to the distribution of the maxillary branch. Modified decompression of the IOC through the maxillary sinus is a safe, highly effective, and minimally invasive method to treat these patients.

A retrospective study of neurocombing for the treatment of trigeminal neuralgia without neurovascular compression

BACKGROUND

Microvascular decompression (MVD) is the most effective and non-ablative treatment for trigeminal neuralgia (TN). However, it is not possible when neurovascular compression (NVC) is absent. Neurocombing is a possible treatment option for TN patients without NVC.

AIM

To evaluate and describe the clinical outcome of neurocombing for the treatment of TN when NVC was absent.

METHODS

We retrospectively reviewed the clinical data of the 37 patients of Type 1 TN without NVC who underwent neurocombing in our department between January 2013 and November 2014. The Barrow Neurological Institute (BNI) Pain Intensity scale, the numerical rating scale (NRS) and the quality of life scale (QOL) were evaluated in four stages-presurgical, immediate, at 1 and at 3 years. Pain recurrence was statistically evaluated with Kaplan-Meier analysis.

RESULTS

All the 37 enrolled patients were proved to have no NVC by imaging or exploration in surgery. The mean follow-up duration was 29.50 months. After the procedure, 35 patients (94.6%) experienced immediate pain relief (BNI I) and 2 patients (5.4%) had occasional pain without any medication (BNI II). At 1 year and 3 years, the rates of successful pain relief (BNI I&II) were 86.5 and 83.3%, respectively. 34 patients (91.9%) suffered from mild facial numbness, while it did not exert a harmful impact on their quality of life.

CONCLUSIONS

This study demonstrated that neurocombing is an attractive, effective, safe and durable treatment option for TN when NVC is absent. Further study is needed to explain the complicated and exact mechanism of pain relief by neurocombing.

Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a sudden, severe, brief, stabbing, and recurrent pain within one or more branches of the trigeminal nerve. Type 1 as intermittent and Type 2 as constant pain represent distinct clinical, pathological, and prognostic entities. Although multiple mechanism involving peripheral pathologies at root (compression or traction), and dysfunctions of brain stem, basal ganglion, and cortical pain modulatory mechanisms could have role, neurovascular conflict is the most accepted theory. Diagnosis is essentially clinically; magnetic resonance imaging is useful to rule out secondary causes, detect pathological changes in affected root and neurovascular compression (NVC). Carbamazepine is the drug of choice; oxcarbazepine, baclofen, lamotrigine, phenytoin, and topiramate are also useful. Multidrug regimens and multidisciplinary approaches are useful in selected patients. Microvascular decompression is surgical treatment of choice in TN resistant to medical management. Patients with significant medical comorbidities, without NVC and multiple sclerosis are generally recommended to undergo gamma knife radiosurgery, percutaneous balloon compression, glycerol rhizotomy, and radiofrequency thermocoagulation procedures. Partial sensory root sectioning is indicated in negative vessel explorations during surgery and large intraneural vein. Endoscopic technique can be used alone for vascular decompression or as an adjuvant to microscope. It allows better visualization of vascular conflict and entire root from pons to ganglion including ventral aspect. The effectiveness and completeness of decompression can be assessed and new vascular conflicts that may be missed by microscope can be identified. It requires less brain retraction.

Efficacy of stereotactic gamma knife surgery and microvascular decompression in the treatment of primary trigeminal neuralgia: a retrospective study of 220 cases from a single center

OBJECTIVES

A retrospective study was undertaken to compare the efficacy of stereotactic gamma knife surgery (GKS) and microvascular decompression (MVD) in the treatment of primary trigeminal neuralgia (TN) at a single center. The study included the evaluation of clinical outcomes of pain relief and pain recurrence and complications associated with GKS and MVD.

METHODS

The study included 202 patients with primary TN and was conducted between January 2013 and December 2014; about 115 patients were treated with GKS and 87 patients were treated with MVD. TN pain was evaluated using the Barrow Neurological Institute and the visual analog scale scoring systems. Preoperative magnetic resonance tomographic angiography was performed for all patients. Microscope-assisted MVD used the suboccipital retrosigmoid sinus approach. GKS targeted the trigeminal nerve root entry zone with a margin radiation dose of 59.5 Gy, and brainstem dose <12 Gy. Posttreatment follow-up was for 2 years.

RESULTS

Postoperative Barrow Neurological Institute scores for patients treated with GKS and MVD were significantly improved compared with preoperative scores (P<0.01). Reduction in postoperative pain following MVD (95.4% patients) was significantly greater than that following GKS (88.7% patients) (P<0.01). Postoperative visual analog scale scores of the MVD group were significantly reduced compared with those of patients treated with GKS at the same postoperative time points (P<0.01). Patients treated with GKS had a significantly increased rate of loss of corneal reflex compared with patients treated with MVD (P=0.002).

CONCLUSION

Both GKS and MVD are safe and effective first-line and adjunctive treatment options for patients with TN. The clinical outcomes of pain relief and reduction of pain recurrence were better with MVD. For GKS, this study showed that the optimal radiation therapeutic dose range was 70-90 Gy, but brainstem radiation protection is recommended.

Trigeminal Neuralgia Due to Red Vein Draining a Supratentorial Arteriovenous Malformation: Case Report

Trigeminal neuralgia (TGN) is rarely caused by arteriovenous malformation (AVM). The AVMs causing TGN are reported mostly in the ipsilateral posterior fossa. The culprit vessels are dilated feeding artery or nidus itself. We present a rare case of TGN caused by dilated draining veins from a supratentorial AVM. The patient suffered from TGN with an incidentally found large AVM, which had been left untreated. The neuralgia was successfully relieved by microvascular decompression. Dilated red veins compressed the nerve at the root entry zone and distant cisternal portion of the nerve. Technically, transposition is not practical for fragile, dilated red veins with high pressure. Interposition is safer method in this case.

Trigeminal neuralgia caused by brain arteriovenous malformations: A case report and literature review

Few cases of trigeminal neuralgia (TGN) induced by brain arteriovenous malformations (bAVMs) have previously been reported. The present case report described one case of TGN caused by bAVMs in a 32-year-old male patient who suffered from recurrent pain in his right cheek for a period of two years, for whom the seizure frequency and duration of pain increased for 6 months. Magnetic resonance imaging was performed, which demonstrated flow-void signals in the abnormal vessels in the right cerebellopontine angle. Subsequent digital subtraction angiography confirmed the diagnosis of bAVMs, and showed the nidus was fed by the right superior cerebellar and the right anterior inferior cerebellar, and drained into the adjacent venous sinuses on the same side. The patient underwent an interventional embolization treatment. TGN was completely relieved following embolization of the majority of the bAVMs. Pain relief may be associated with blocking of the pulsatile compression of the feeding arteries of the bAVMs, the arterialized draining veins or the malformed niduses following embolization, which is similar to the effects induced by microvascular decompression surgery of the trigeminal nerve. In the present case study and review, the underlying mechanism and treatment strategy of TGN caused by bAVMs were discussed in the context of present case, and a literature review was carried out.

Occurrence of Herpes Simplex Virus Reactivation Suggests a Mechanism of Trigeminal Neuralgia Surgical Efficacy

Common to the types of surgery that are effective for the treatment of trigeminal neuralgia (TN) is reactivation of herpes simplex virus (HSV). It is likely that such HSV reactivation following surgery indicates altered trigeminal ganglion neuron function, which was caused by the surgery. It is not thought that HSV infection is related to the cause of TN or that HSV reactivation is important for surgical treatment efficacy. Rather, it is thought that HSV reactivation is a marker of altered trigeminal ganglion neuron function resulting from the TN surgery. It is suggested that HSV reactivation is a surrogate marker of ganglion neuron injury. The correlation between effective types of surgery and evidence that they alter ganglion neuron function suggests that altered trigeminal ganglion neuron function may be the basis of the surgical efficacy.

Altered Autonomic Nervous System Reactivity to Pain in Trigeminal Neuralgia

Background: In the past two decades, there has been increasing evidence to suggest that trigeminal neuralgia (TN) may be linked to a dysfunction of the autonomic nervous system (ANS). The aim of the present study was to formally test this hypothesis by comparing the reactivity of the ANS to experimental pain in a population of TN patients and healthy controls. Methods: Twelve patients diagnosed with classical TN and 12 healthy controls participated in the study. Cardiac activity was assessed while participants were instructed to rest and again during a cold pressor test (CPT). Heart rate variability analyses were performed off-line to obtain parasympathetic (high-frequency) and sympathetic (low-frequency) indices. Results: At baseline, ANS measures did not differ between healthy controls and TN patients, and both groups showed a similar increase in heart rate during the CPT (all p values >0.05). However, TN patients showed a greater increase in cardiac sympathetic activity and a greater decrease in cardiac parasympathetic activity during CPT compared with healthy controls (all p values <0.05). Importantly, changes in sympathetic reactivity, from baseline to CPT, were negatively associated with the number of pain paroxysms experienced each day by TN patients in the preceding week (r=−.58, p<0.05). Conclusions: These results suggest that TN, like many other short-lasting, unilateral facial pain conditions, is linked to ANS alterations. Future studies are required to determine if the altered ANS response observed in TN patients is a cause or a consequence of TN pain

Trigeminal root compression for trigeminal neuralgia in patients with no vascular compression

BACKGROUND

Trigeminal neuralgia (TN) may be present in the absence of vascular compressiom, and surgical treatment in these cases is controversial. Our objective is to evaluate the efficacy and safety of trigeminal root compression in this situation.

METHODS

A prospective collection of clinical data on all patients diagnosed with idiopathic TN in our institution. Cases with no visible offending vessel intraoperatively were included in this study. These patients underwent trigeminal root compression and long-term follow-up. The basic characteristics and outcomes were analyzed.

RESULTS

From February 2005 to November 2010, 381 patients underwent microvascular decompression for TN at our department. Among them, 28(7.3 %) patients (17 female, 11 male) had no visible vascular compression intraoperatively. The median observation period was 46 months (range, 8-60 months). Twenty patients (71.4 %) achieved complete pain relief without medication immediately postoperatively. However, the recurrence rate was 38.4 %, and only 13 patients (46.4 %) achieved complete pain relief without medication at follow-up. Ten patients (35.7 %) developed some degree of facial numbness, which was transient in six cases (21.4 %) and permanent in four (14.3 %).

CONCLUSIONS

Although trigeminal root compression provides good initial pain relief, the long-term efficacy, complication and recurrence rates are far from satisfactory. Further studies are needed to explore the possible mechanisms of underlying pain and to compare the outcomes of various types of interventions in cases without vascular compression.

Etiologic exploration of magnetic resonance tomographic angiography negative trigeminal neuralgia

Our objective was to explore the etiologic factors involved in trigeminal neuralgia with negative magnetic resonance tomographic angiography (MRTA) results. Clinical data from 341 patients with idiopathic trigeminal neuralgia who were treated with neurovascular decompression between March 2003 and December 2011 were retrospectively analyzed. The etiologic causes of preoperative MRTA-negative trigeminal neuralgia were categorized based on comparisons between preoperative MRTA and intraoperative endoscopic images. MRTA was highly sensitive (92.4%, 291/315) to neurovascular compression, whereas its specificity was 65.4% (17/26). Among the 24 false-negative cases, there were nine patients with petrosal vein compression, 12 with superior cerebellar artery compression, two with superior cerebellar arterial branch compression, and one patient with anterior inferior cerebellar artery compression. Among the 17 true-negative cases, three patients had arachnoid adhesions, one had a protruding temporal eminence, five had micro-cholesteatomas, and eight patients exhibited no compression. The factors responsible for the MRTA-negative results included small-diameter arterial vessels, veins with slow blood flow, arachnoid adhesions, protruding temporal eminences, micro-cholesteatomas, and other pathologies such as multiple sclerosis. Preoperative diagnoses of MRTA-negative patients need to integrate the MRI results from multiple sequences to discriminate between arteriolar compression, venous compression, and small compressive lesions. When narrow cerebellopontine angles are shown in MRTA, arachnoid adhesion and temporal eminence compression should be considered.

The long-term outcome of nerve combing for trigeminal neuralgia

BACKGROUND

The purpose of our study was to describe and evaluate the long-term clinical outcome of nerve combing for idiopathic trigeminal neuralgia (TN) with and without vascular compression.

METHODS

The study included 60 trigeminal neuralgia patients, 28 of which (Group A) had no visible vascular compression intraoperatively and 32 of which (Group B) had trigeminal nerve root entry zone (REZ) compressed by vascular structure. All patients were considered medical failures prior to the surgeries. All of them underwent trigeminal nerve combing. The following outcome measures were assessed: pain relief, recurrence, complication and time to pain relief.

RESULTS

The median duration of follow-up was 52 months (range 48-96 months) in group A and 56 months (range 48-96 months) in group B. Excellent relief and good relief were noted in 23 patients (82.1 %) and two patients (7.1 %) from group A, respectively, and in 20 (62.5 %) and eight patients (25 %) from group B. The major complication of both groups was facial numbness. And the total complication rate was 15.8 % in group A and 18.8 % in group B. Recurrence was found in one patient in group A and in two in group B by the end of follow-up.

CONCLUSION

Trigeminal nerve combing is effective in treating TN, but has a much higher pain relief rate in patients without vascular compression than those with vascular compression.

Intrinsic arteriovenous malformation embedded in the trigeminal nerve of a patient with trigeminal neuralgia

A 66-year-old man presented with typical right trigeminal neuralgia. Neuroimaging showed a small arteriovenous malformation (AVM) in the right cerebellopontine angle. Suboccipital craniotomy verified that the AVM was almost completely embedded in the root entry zone of the trigeminal nerve and the nerve axis was tilted infero-posteriorly. The patient obtained complete pain relief without sequelae after surgery by transposition of the superior cerebellar artery and correction of the tilted nerve axis. The nidus of the unresected AVM was obliterated by gamma knife radiosurgery.

Efficacy and safety of root compression of trigeminal nerve for trigeminal neuralgia without evidence of vascular compression

OBJECTIVE

Trigeminal neuralgia (TN) surgical treatment with microvascular decompression is highly effective and safe, but for a percentage of patients who undergo this procedure, no vascular compression is found. The purpose of this study was to evaluate the long-term efficacy with trigeminal root compression of the trigeminal nerve in patients with TN refractory to medical treatment who underwent neurosurgical management by a retrosigmoid approach of the cerebellopontine angle and were found to be negative for vascular compression.

METHODS

A prospective collection of clinical data on all patients with a diagnosis of idiopathic TN was conducted at our institution. A total of 277 patients with TN were treated by a keyhole retrosigmoid approach for exploration of the cerebellopontine angle between January of 2000 and August of 2010. A total of 44 patients were found to be negative for vascular compression of the trigeminal nerve; all of these patients underwent trigeminal root compression.

RESULTS

We found that all patients were pain free after the procedure. There was a 27% relapse in a mean time of 10 months, but 83% of these patients were adequately controlled by medical treatment, and only 17% needed a complementary procedure for pain relief. We also found that 63% of the patients complained of a partial loss of facial sensitivity, but only 1 patient presented with a corneal ulcer. There was a 6.7% rate of significant complications.

CONCLUSIONS

We concluded that trigeminal root compression is a safe and effective option for patients with primary TN without vascular compression.

Trigeminal neuralgia caused by a fibrous ring around the nerve

Trigeminal neuralgia is usually caused by compression of the nerve by vessels or a tumor. The authors report a case of trigeminal neuralgia not caused by vessel/tumor compression but by a constricting fibrous band around the trigeminal nerve. A 26-year-old man presented with typical trigeminal neuralgia. Although a gradient echo MR imaging demonstrated no offending vessel or a tumor, the patient agreed to undergo exploratory surgery. Intraoperatively, there were no vessels that could be the cause of the neuralgia; instead, the trigeminal nerve was constricted near the root entry zone. After the fiber was cautiously cut, the nerve expanded slightly. The neuralgia resolved without any neurological deficit, and the postoperative course was uneventful. A fibrous band around the trigeminal nerve can cause trigeminal neuralgia. When the symptom is typical and gradient echo MR imaging shows constriction of the trigeminal nerve, surgery is recommended to release the constricted the trigeminal nerve.

A prospective study of 39 patients with trigeminal neuralgia treated with percutaneous balloon compression

OBJECTIVE

Trigeminal neuralgia is the most common facial pain. It may be treated with percutaneous balloon compression (PBC), which is considered to be a safe and efficient procedure. The purpose of this study was to review our results with PBC and to assess the factors influencing the outcome.

METHOD

A multivariate analysis was used to study 39 patients during a 50-month postoperative period.

RESULTS

There was predominance of the female gender (54%), the right side of the face (84%) and V2V3 roots of trigeminal nerve (33%). The mean age was 62.3 years. No major complications or deaths occurred. Among all variables, postoperative hypoesthesia was the single prognostic factor capable of positively influencing the results (p=0.02). Most patients (80%) were pain-free after 50 months with a 90% satisfaction rate.

CONCLUSION

PBC was a safe procedure with low morbidity, no mortality, high approval ratings, and was an important improving on patients' quality of life.

Unusual recurrence of trigeminal neuralgia after microvascular decompression by muscle interposal

BACKGROUND

Patients with trigeminal neuralgia (TN) and persistent or recurrent facial pain after microvascular decompression (MVD) typically undergo less invasive procedures in the hope of providing pain relief. However, re-operation should be considered in selected patients.

CASE REPORT

A 48-year-old woman presented with recurrent trigeminal neuralgia (TN) 3 years following microvascular decompression (MVD). The patient underwent brain magnetic resonance angiography (MRA), which did not reveal neurovascular compression; therefore surgical re-exploration was carried out. During the operation, the fifth cranial nerve was seen without impingement from any blood vessels; however, a very firm tissue was observed and identified as the muscle fragment from the previous MVD procedure. The fifth cranial nerve was carefully separated from the muscle. Thereafter, the right SCA was dissected out from the muscle and suspended by a periosteum tape sutured to the nearby dura.

CONCLUSIONS

Our findings, along with similar cases reported in the literature, support the development of new inert materials and alternative surgical strategies that can limit TN recurrence.