Partial sensory trigeminal rhizotomy at the pons for trigeminal neuralgia

Efficacy and safety of microvascular decompression with or without partial sensory rhizotomy: a comprehensive meta-analysis and systematic review in treating trigeminal neuralgia

Classical trigeminal neuralgia (TN), caused by vascular compression of the nerve root, is a severe cause of pain with a considerable impact on a patient's quality of life. While microvascular decompression (MVD) has lower recurrence rates when compared with partial sensory rhizotomy (PSR) alone, refractoriness can still be as high as 47%. We aimed to assess the efficacy and safety profile of MVD + PSR when compared to standalone MVD for TN. We searched Medline, Embase, and Web of Science following PRISMA guidelines. Eligible studies included those with ≥ 4 patients, in English, published between January 1980 and December 2023, comparing MVD vs. MVD + PSR for TN. Endpoints were pain cure, immediate post-operative pain improvement, long-term effectiveness, long-term recurrence, and complications (facial numbness, hearing loss, and intracranial bleeding). We pooled odds ratios (OR) with 95% confidence intervals with a random-effects model. I2 was used to assess heterogeneity, and sensitivity and Baujat analysis were conducted to address high heterogeneity. Eight studies were included, comprising a total of 1,338 patients, of whom 1,011 were treated with MVD and 327 with MVD + PSR. Pain cure analysis revealed a lower likelihood of pain cure in patients treated with MVD when compared to patients treated with MVD + PSR (OR = 0.30, 95% CI: 0.13 to 0.72). Immediate postoperative pain improvement assessment revealed a lower likelihood of improvement in the MVD group when compared with the MVD + PSR group (OR = 0.31, 95% CI: 0.10 to 0.95). Facial numbness assessment revealed a lower likelihood of occurrence in MVD alone when compared to MVD + PSR (OR = 0.08, 95% CI: 0.04 to 0.15). Long-term effectiveness, long-term recurrence, hearing loss, and intracranial bleeding analyses revealed no difference between both approaches. Our meta-analysis identified that MVD + PSR was superior to MVD for pain cure and immediate postoperative pain improvement for treating TN. However, MVD + PSR demonstrated a higher likelihood of facial numbness complications. Furthermore, identified that hearing loss and intracranial bleeding complications appear comparable between the two treatments, and no difference between long-term effectiveness and recurrence.

Neurosurgical Treatment of Pain

The aim of this review is to draw attention to neurosurgical approaches for treating chronic and opioid-resistant pain. In a first chapter, an up-to-date overview of the main pathophysiological mechanisms of pain has been carried out, with special emphasis on the details in which the surgical treatment is based. In a second part, the principal indications and results of different surgical approaches are reviewed. Cordotomy, Myelotomy, DREZ lesions, Trigeminal Nucleotomy, Mesencephalotomy, and Cingulotomy are revisited. Ablative procedures have a limited role in the management of chronic non-cancer pain, but they continues to help patients with refractory cancer-related pain. Another ablation lesion has been named and excluded, due to lack of current relevance. Peripheral Nerve, Spine Cord, and the principal possibilities of Deep Brain and Motor Cortex Stimulation are also revisited. Regarding electrical neuromodulation, patient selection remains a challenge.

Surgical treatment for Trigeminal neuralgia

Various treatments for trigeminal neuralgia (TN) are known to yield initial satisfactory results; however, the surgical treatment has excellent long-term outcomes and a low recurrence rate. Surgical treatment addresses the challenge of vascular compression, which accounts for 85% of the causes of TN. As for surgical treatment for TN, microvascular decompression (MVD) has become the surgical treatment of choice after Peter J. Jannetta reported the results of MVD surgery in 1996. Since then, many studies have reported a success rate of over 90% for the initial surgical treatment. Most MVDs aim to separate (decompress) the culprit vessel from the trigeminal nerve. To increase the success rate of surgery, accurate indications for MVD and management of the offender vessels without complications are critical. In addition, if there is no vascular compression, partial sensory rhizotomy or internal neurolysis can be performed to improve surgical outcomes.

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.

Preoperative evaluation of neurovascular relationships for microvascular decompression: Visualization using Brainvis in patients with idiopathic trigeminal neuralgia

OBJECTIVE

A precise and accurate evaluation of neurovascular relationships in patients with idiopathic trigeminal neuralgia (ITN) scheduled for microvascular decompression is necessary. Thus, we constructed and evaluated a fusion imaging technique combining multi-source heterogeneous imaging data from three-dimensional magnetic resonance (MR) and computerized tomography venoangiography (CTV), which enabled use of virtual reality to preoperatively assess the neurovascular relationships, in patients with ITN scheduled for microvascular decompression.

METHODS

A single-center observational study. In total, eight patients with ITN scheduled for microvascular decompression were included. Patients underwent three-dimensional MR imaging with time-of-flight (TOF) and fast imaging employing steady state acquisition (FIESTA) sequences and CTV before microvascular decompression. A fusion imaging technique, combining MR-TOF, MR-FIESTA, and CTV images, was used to construct a three-dimensional model with information regarding the facial and auditory nerves, brain tissue, skull, arteries and veins. The positions of the trigeminal nerve and the responsible vessels were observed. The agreement between intraoperative neurovascular compression findings and preoperative evaluation results, and the duration required to determine the neurovascular relationships, were evaluated.

RESULTS

The neurovascular relationships as determined with the fusion imaging technique were consistent with intraoperative neurovascular compression findings in all patients. Moreover, the assessment duration was significantly shorter with the fusion imaging technique than with the three-dimensional MR (P<0.05). The rate of an accurate assessment was significantly higher with the fusion imaging technique than with three-dimensional MR (P<0.05).

CONCLUSIONS

The fusion imaging technique is a useful tool for the diagnosis and decision-making process based on neurovascular relationships in patients with ITN scheduled for microvascular decompression.

Value of Partial Sensory Rhizotomy in the Microsurgical Treatment of Trigeminal Neuralgia Through Retrosigmoid Approach

Purpose

Microvascular decompression (MVD) is the most effective surgical procedure for the treatment of refractory primary trigeminal neuralgia (TN), but due to the presence of non-neurovascular compression (NVC), the application of MVD is limited. In some cases, partial sensory rhizotomy (PSR) is required. The purpose of this study was to compare the outcome of MVD and MVD+PSR in the treatment of primary TN and to evaluate the application value of PSR in the treatment of TN.

Patients and Methods

We retrospectively analyzed the postoperative outcomes of patients who received MVD or MVD+PSR for the first time from the same surgeon in the neurosurgery department of China-Japan Friendship Hospital from March 2009 to December 2017. A total of 105 patients were included in the data analysis, including 40 in the MVD group and 65 in the MVD+PSR group.

Results

The MVD group had an effectiveness rate of 60% and a recurrence rate of 31.4% after an average follow-up of 49.4 months. The MVD+PSR group had an average effectiveness rate of 69.2% and a recurrence rate of 28.6% after an average follow-up of 71.4 months. There was no statistically significant intergroup difference in long-term effectiveness (p=0.333) or recurrence rates (p=0.819). The incidence of facial numbness was significantly higher in the MVD+PSR group than in the MVD group (83.1% vs 7.5%; p<0.001). However, facial numbness had no significant effect on the patients’ daily life.

Conclusion

MVD+PSR and MVD have the same effectiveness in the treatment of primary TN. MVD+PSR is associated with a higher incidence of facial numbness than MVD, but the difference does not affect the patients’ daily life. PSR should have a place in the treatment of TN by posterior fossa microsurgery.

The Long-Term Outcomes and Predictors of Microvascular Decompression with or without Partial Sensory Rhizotomy for Trigeminal Neuralgia

Purpose

Microvascular decompression (MVD) and MVD combined with partial sensory rhizotomy (PSR) are effective surgical treatments for idiopathic trigeminal neuralgia (TN). The aim of this study was to compare the long-term outcomes of both MVD and MVD+PSR for the treatment of TN and to identify the factors that may influence the long-term outcomes after MVD or MVD+PSR.

Patients and Methods

From March 2009 to December 2017, 99 patients with idiopathic TN who underwent MVD or MVD+PSR in our hospital (40 MVD, 59 MVD+PSR) were included in the study. The indications for MVD+PSR were as follows: vessels only contacted the nerve root, absence of arterial conflict, or failing to completely decompress from the arteries or veins. All patients were treated by one neurosurgeon and were followed up for at least 1 year. The outcomes were assessed with the Barrow Neurological Institute (BNI) Pain Intensity Scale.

Results

The average follow-up duration was 63.0 months (range, 13.2-118.8 months). Patients in the MVD group were younger than those in the MVD+PSR group (55.1 years and 60.5 years, respectively, P=0.012). A total of 62.5% of the patients in the MVD group and 69.5% of the patients in the MVD+PSR group had favorable long-term outcomes. The Kaplan-Meier survival analysis showed no significant difference in long-term outcomes between the two groups (P=0.202). No factors were associated with long-term outcomes after MVD. For MVD+PSR, a long duration of the disease (odds ratio (OR) 6.967, P=0.016) was associated with unfavorable long-term outcomes, whereas pure arterial compression (OR 0.131, P=0.013) was associated with favorable long-term outcomes.

Conclusion

For patients who are not suitable to undergo pure MVD, MVD+PSR can be used as an effective alternative. For MVD+PSR, patients with a long duration of symptoms may have poor long-term outcomes, while patients with pure arterial compression may have favorable long-term outcomes.

Microvascular decompression for treating classical trigeminal neuralgia: can we offer the gold standard therapy to older patients?

PURPOSE

Microvascular decompression is the most successful procedure for treating classic trigeminal neuralgia. However, due to the risks of surgery and anesthesia, the procedure is performed less frequently in older patients. The aim of the study is to investigate the intraoperative and perioperative morbidity in older patients who underwent this surgical treatment.

METHODS

Patients who underwent microvascular decompression in our department between 2004 and 2016 were divided into two age groups (A: < 69 years old, n = 114; B: ≥ 70 years old, n = 47). Retrospectively, the pre-, intra- and postoperative data were analyzed.

RESULTS

Older patients showed a statistically significant prolonged duration of symptoms until surgery (mean 127 months vs. 70 months; p < 0.001). They also showed a significantly increased necessity for duroplasty (p = 0.015), but with no increased incidence of postoperative cerebrospinal fluid leakage or rhinoliquorrhea. A comparable postoperative course was found in both groups. Over 90% in both groups had a significantly postoperative improvement. There were no cardiopulmonary complications or infections in either group. In the 3-month follow-up, there was a comparable success of pain reduction and no increased incidence of sensory disturbances.

CONCLUSIONS

Based on the high chances of success and low morbidity, microvascular decompression should also be offered to older patients with anesthesiologic agreement.

Trigeminal root massage in microsurgical treatment of trigeminal neuralgia patients without arterial compression: When, how and why

BACKGROUND

During the microsurgical exploration of trigeminal root in the pontocerebellar angle in patients with primary trigeminal neuralgia (TN) without an evident arterial compression, the surgeon is in an engaged situation because there are not well-established surgical strategies. The aim of this study is to describe in these cases the surgical maneuver we call "trigeminal root massage" (TRM).

METHODS

52 consecutive patients with primary trigeminal neuralgia who had undergone a microsurgical suboccipital retrosigmoid exploration of trigeminal root were reviewed. Among them we found 10 patients without an evident arterial compression after a thorough microsurgical exploration. In the great majority of these 10 cases, we noticed a venous contact to the trigeminal root along this cisternal trajectory, in most cases we have had to coagulate the compressive vein/s and then cut. All underwent a simple trigeminal root massage, without interposition of any material implant.

RESULTS

All 10 patients experienced immediate pain disappearance and the postoperative course was uneventful except one case with a severe complication: cerebellar swelling, meningitis and hydrocephaly. The recurrence rate was 40%. Six patients achieved pain relief without specific medication with an average follow-up period of 5 years. There have been no mortalities nor any postoperative anesthesia dolorosa.

CONCLUSIONS

The described maneuver provides an easy and simple alternative way in cases where during a microsurgical exploration of trigeminal root, where we don't find a clear arterial compression, with similar results than other possibilities such as partial sensory rhizotomy or more complicated and time consuming surgery as "nerve combing". Nevertheless, a 40% of pain recurrence after an average follow-up of 5 years means that is a good alternative, but not a definitive technique at the moment for permanent cure of trigeminal neuralgia without arterial compression.

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.

Impact of pain and postoperative complications on patient-reported outcome measures 5 years after microvascular decompression or partial sensory rhizotomy for trigeminal neuralgia

Background

Microvascular decompression (MVD) and partial sensory rhizotomy (PSR) provide longstanding pain relief in trigeminal neuralgia (TN). Given their invasiveness, complications can result from such posterior fossa procedures, but the impact of these procedures and their complications on patient-reported outcome measures (PROM), such as quality of life and distress, are not well established.

Method

Five years after surgery, patients who underwent first MVD or PSR for TN at one institution, between 1982 and 2002, were sent a self-completion assessment set containing a range of PROMs: the Short Form-12 (SF-12) questionnaire to assess quality of life, the Hospital Anxiety and Depression Scale (HADS) to assess distress, and a questionnaire containing questions about postoperative complications, their severity and impact on quality of life. These findings and demographic data were compared between MVD and PSR.

Results

One hundred and eighty-one of 245 (73.9%) patients after first MVD and 49 of 60 (81.7%) after PSR responded, and were included in analyses. The mean SF-12 scores of patients after MVD and PSR at five-year follow-up were significantly lower than English age-matched norms. Though there were no differences in SF-12 physical or mental component scores between the two procedures, patients after PSR were more likely to have case-level anxiety (RR = 3.3; 95% CI, 1.1–10.5; p = 0.03), had more postoperative complications, and of greater severity, including pain (RR = 2.52; 95% CI, 1.5–4.1; p < 0.001), numbness (RR = 5.9; 95% CI, 3.8–9.2; p < 0.001), burning sensations (RR = 3.0; 95% CI, 1.5–5.8; p = 0.001) and difficulty in eating (RR = 17.1; 95% CI, 5.6–53.1; p < 0.001), and these had a larger impact on quality of life for PSR compared to MVD.

Conclusions

The quality of life 5 years after MVD or PSR is poorer than in the general population and associated with postoperative complications such as pain, numbness, burning sensation and difficulty in eating. These complications are commoner after PSR than MVD, and this is associated with anxiety in PSR patients at five-year follow-up. However, these differences are not reflected by quality of life scores. Outcome measures need to incorporate patient experience after treatment for TN, and represent patient priorities for quality of life.

Electronic supplementary material

The online version of this article (10.1007/s00701-017-3350-6) contains supplementary material, which is available to authorized users.

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.

Trigeminal neuralgia without neurovascular compression presents earlier than trigeminal neuralgia with neurovascular compression

OBJECT

Trigeminal neuralgia (TN) occurs and recurs in the absence of neurovascular compression (NVC). To characterize what may be distinct patient populations, the authors examined age at onset in patients with TN with and without NVC.

METHODS

A retrospective review of patients undergoing posterior fossa surgery for Type I TN at Oregon Health & Science University from 2009 to 2013 was undertaken. Charts were reviewed, and imaging and operative data were collected for patients with and without NVC. Mean, median, and the empirical cumulative distribution of onset age were determined. Statistical analysis was performed using Student t-test, Wilcoxon and Kolmogorov-Smirnoff tests, and Kaplan-Meier analysis. Multivariate analysis was performed using a Cox proportional hazards model.

RESULTS

The charts of 219 patients with TN were reviewed. There were 156 patients who underwent posterior fossa exploration and microvascular decompression or internal neurolysis: 129 patients with NVC and 27 without NVC. Mean age at symptoms onset for patients with and without NVC was 51.1 and 42.6 years, respectively. This difference (8.4 years) was significant (t-test: p = 0.007), with sufficient power to detect an effect size of 8.2 years. Median age between groups with and without NVC was 53.25 and 41.2 years, respectively (p = 0.003). Histogram analysis revealed a bimodal age at onset in patients without NVC, and cumulative distribution of age at onset revealed an earlier presentation of symptoms (p = 0.003) in patients without NVC. Chi-square analysis revealed a trend toward female predominance in patients without NVC, which was not significant (p = 0.08). Multivariate analysis revealed that age at onset was related to NVC but not sex, symptom side or distribution, or patient response to medical treatment.

CONCLUSIONS

NVC is neither sufficient nor necessary for the development of TN. Patients with TN without NVC may represent a distinct population of younger, predominantly female patients. Further research into the pathophysiology underlying this debilitating disease is needed.

Long-term efficacy and safety of internal neurolysis for trigeminal neuralgia without neurovascular compression

OBJECT Trigeminal neuralgia (TN) occurs and recurs in the absence of neurovascular compression (NVC). While microvascular decompression (MVD) is the most effective treatment for TN, it is not possible when NVC is not present. Therefore, the authors sought to evaluate the safety, efficacy, and durability of internal neurolysis (IN), or "nerve combing," as a treatment for TN without NVC. METHODS This was a retrospective review of all cases of Type 1 TN involving all patients 18 years of age or older who underwent evaluation (and surgery when appropriate) at Oregon Health & Science University between July 2006 and February 2013. Chart reviews and telephone interviews were conducted to assess patient outcomes. Pain intensity was evaluated with the Barrow Neurological Institute (BNI) Pain Intensity scale, and the Brief Pain Inventory-Facial (BPI-Facial) was used to assess general and face-specific activity. Pain-free survival and durability of successful pain relief (BNI pain scores of 1 or 2) were statistically evaluated with Kaplan-Meier analysis. Prognostic factors were identified and analyzed using Cox proportional hazards regression. RESULTS A total of 177 patients with Type 1 TN were identified. A subgroup of 27 was found to have no NVC on high-resolution MRI/MR angiography or at surgery. These patients were significantly younger than patients with classic Type 1 TN. Long-term follow-up was available for 26 of 27 patients, and 23 responded to the telephone survey. The median follow-up duration was 43.4 months. Immediate postoperative results were comparable to MVD, with 85% of patients pain free and 96% of patients with successful pain relief. At 1 year and 5 years, the rate of pain-free survival was 58% and 47%, respectively. Successful pain relief at those intervals was maintained in 77% and 72% of patients. Almost all patients experienced some degree of numbness or hypesthesia (96%), but in patients with successful pain relief, this numbness did not significantly impact their quality of life. There was 1 patient with a CSF leak and 1 patient with anesthesia dolorosa. Previous treatment for TN was identified as a poor prognostic factor for successful outcome. CONCLUSIONS This is the first report of IN with meaningful outcomes data. This study demonstrated that IN is a safe, effective, and durable treatment for TN in the absence of NVC. Pain-free outcomes with IN appeared to be more durable than radiofrequency gangliolysis, and IN appears to be more effective than stereotactic radiosurgery, 2 alternatives to posterior fossa exploration in cases of TN without NVC. Given the younger age distribution of patients in this group, consideration should be given to performing IN as an initial treatment. Accrual of further outcomes data is warranted.

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.

Comparative evaluation of surgical procedures for trigeminal neuralgia

Trigeminal neuralgia (TN) is a debilitating ailment. Pharmacotherapy still remains the first line therapy for the management of TN. However, often the patients become refractory to the pharmacotherapy and need surgical interventions. There is a wide array of surgical treatment modalities available for TN and it is important to select the most appropriate surgery for a patient. This review evaluates the various surgical modalities by employing a comparative analysis with respect to patient selection, success rate, complications and cost effectiveness. For the evaluation, a critical review of literature was done with predefined search terms to obtain the details of individual procedures, which were then compared, under similar parameters. The results suggested that microvascular decompression seem to be the most effective treatment in terms of patient satisfaction and long term cost effectiveness. However, if patient factors do not permit, then the peripheral procedures may be employed as a substitute, though they have higher recurrence rate and complications and have relatively lower long term cost effectiveness. The newer modalities like stereotactic radiosurgery and botulinum injections have promising results and further refinement in these procedures will provide additional options for the patients suffering from TN.

Operative treatment of trigeminal neuralgia: review of current techniques

Surgical approaches to pain management are performed when medication cannot control pain or patients cannot tolerate the adverse effects of the medication. Microvascular decompression (MVD) is generally performed when the patient is healthy and relatively young. Partial sensory rhizotomy is performed in addition to, or instead of MVD, in patients in whom significant compression of the trigeminal sensory root does not exist or in whom MVD is technically not feasible. Three percutaneous ablative procedures and gamma knife radiosurgery (GKS) are also performed when MVD cannot be performed. The result of MVD is superior to that of the 3 ablative procedures. GKS is inferior to the 3 ablative procedures in terms of initial pain relief and recurrence, but superior in terms of complications. Peripheral procedures are usually performed in patients not suitable for or not wishing to have other procedures. However, no strict rules exist and each patient should be evaluated individually.

Surgical treatment of trigeminal neuralgia without vascular compression: 20 years of experience

BACKGROUND

There are few reports on the outcome of surgical treatment of TGN without vascular compression.

METHODS

Between 1984 and 2004, 668 patients underwent MVD for TGN. In 21 patients (3.1%), vascular compression was absent. The surgical strategy in these cases involved the following: (1) dissection and exposure of the entire trigeminal nerve root; (2) slight neurapraxia with bipolar tips at the trigeminal nerve root; and (3) isolation of trigeminal nerve with Teflon sponge fragments.

RESULTS

The patients' (female/male, 20:1) ages ranged from 33 to 77 years. Their right side was the most frequently involved (61.9%). Their mean duration of pain before treatment was 7.6 years (range = 1-20 years). At surgical exploration, vascular compression or anatomical abnormalities were absent in 15 patients (71.4%), arachnoidal thickening was present in 5 (23.8%), and fiber dissociation of the trigeminal nerve was present in 1 (4.8%). Mean follow-up after surgery was 17.7 months (range = 4-65 months). Immediate relief from pain occurred in all 21 patients. On Kaplan-Meier analysis, recurrence was maintained at 14.8% for 12, 24, and 36 months, increasing to 43.2% at 48 months. Permanent hypoesthesia was present in 6 patients (28.6%), whereas loss of corneal reflex was observed transiently in 1 (4.8%). Motor function of the trigeminal nerve was intact in all patients. No other complication was found.

CONCLUSION

The proposed surgical plan of standard MVD plus slight trigeminal nerve root neurapraxia is a safe and effective management option for TGN without vascular compression.

Central demyelination of the Vth nerve root in trigeminal neuralgia associated with vascular compression

We have examined the ultrastructure of the trigeminal sensory nerve root in three patients with medically intractable trigeminal neuralgia. In one patient, the nerve root was sandwiched between a large vein and a small pontine artery, in the others compression was due to marked dolichoectasia of a verterbal artery. Because these were not amenable to microvascular decompression, a caudal rhizotomy was performed, by excising a short inferior segment of nerve root in the region of indentation. In all cases, examination revealed a zone of chronic demyelination in the proximal (centrally myelinated) part of the root, near its junction with peripheral nerve. The zone of demyelination contained closely packed axons without intervening glial cytoplasm. Also present were small numbers of thinly myelinated axons. In some cases a single thin myelin sheath encircled several adjacent axons that were still in close apposition. These findings indicate that the trigeminal neuralgia associated with vascular compression is due to demyelination. The demyelination is associated with some evidence of remyelination. The latter phenomenon may account in part for the long periods of remission, especially during the initial period after the onset of trigeminal neuralgia. The partly aberrant nature of the myelination within the region of vascular compression may contribute to the persistence of symptoms in some patients after decompressive surgery.

Neuro-ophthalmic considerations in trigeminal neuralgia and its surgical treatment

PURPOSE OF REVIEW

In this review, we will briefly discuss the clinical manifestations and etiology of trigeminal neuralgia, outline the neuro-ophthalmic features of trigeminal neuralgia, and detail the neuro-ophthalmic side effects and complications of the surgical treatment of trigeminal neuralgia.

RECENT FINDINGS

There is a variety of surgical treatment modalities available for patients with trigeminal neuralgia intolerable or resistant to medical therapy. Significant ocular and visual morbidity can result from the surgical treatment of trigeminal neuralgia.

SUMMARY

Percutaneous or open surgical procedures for trigeminal neuralgia can result in corneal anesthesia, neurotrophic keratitis, exposure keratitis, herpetic keratitis, ocular motor cranial neuropathies, and optic neuropathy. Ophthalmologists should be aware of these potential problems because they may need to evaluate and provide care to patients with ocular or visual complaints following surgery for trigeminal neuralgia.

Microvascular decompression surgery in the United States, 1996 to 2000: mortality rates, morbidity rates, and the effects of hospital and surgeon volumes

OBJECTIVE

Microvascular decompression (MVD) is associated with low mortality and morbidity rates at specialized centers, but many MVD procedures are performed outside such centers. We studied short-term end points after MVD in a national hospital discharge database sample.

METHODS

A retrospective cohort study was performed by using the Nationwide Inpatient Sample, 1996 to 2000.

RESULTS

The sample included 1326 MVD procedures for treatment of trigeminal neuralgia, 237 for treatment of hemifacial spasm, and 27 for treatment of glossopharyngeal neuralgia, performed at 305 hospitals by 277 identified surgeons. The mortality rate was 0.3%, and the rate of discharge other than to home was 3.8%. Neurological complications were coded in 1.7% of cases, hematomas in 0.5%, and facial palsies in 0.6%, with 0.4% of patients requiring ventriculostomies and 0.7% postoperative ventilation. Trigeminal nerve section was also coded for 3.4% of patients with trigeminal neuralgia, more commonly among older patients (P = 0.08), among female patients (P = 0.03), and at teaching hospitals (P = 0.02). The median annual caseloads were 5 cases per hospital (range, 1-195 cases) and 3 cases per surgeon (range, 1-107 cases). With adjustment for age, sex, race, primary insurance, diagnosis (trigeminal neuralgia versus hemifacial spasm versus glossopharyngeal neuralgia), geographic region, admission type and source, and medical comorbidities, outcomes at discharge were superior at higher-volume hospitals (P = 0.006) and with higher-volume surgeons (P = 0.02). Complications were less frequent after surgery performed at high-volume hospitals (P = 0.04) or by high-volume surgeons (P = 0.01). The rate of discharge other than to home was 5.1% for the lowest-volume-quartile hospitals, compared with 1.6% for the highest-volume-quartile hospitals. Volume and mortality rate were not significantly related, but three of the four deaths in the series followed procedures performed by surgeons who had performed only one MVD procedure that year. Length of stay (median, 3 d) and hospital volume were not significantly related. Hospital charges were slightly higher at higher-volume hospitals (P = 0.007).

CONCLUSION

Although most MVD procedures in the United States are performed at low-volume centers, mortality rates remain low. Morbidity rates are significantly lower at high-volume hospitals and with high-volume surgeons.

Trigeminal Neuralgia

The initial treatment for trigeminal neuralgia is medical. Carbamazepine is the drug of choice. If the patient proves to be intolerant of carbamazepine, a number of second-line drugs are available, though data on their relative efficacy are nonexistent. Phenytoin, baclofen, clonazepam, and sodium valproate are all worthy of consideration. Oxcarbazepine may be as effective as carbamazepine, but its availability is limited. Newer agents being tried in this condition include lamotrigine and gabapentin. Their comparative value has not been established. For patients resistant to or intolerant of drug therapy, interventional or surgical procedures are necessary. For younger, fit patients, particularly with involvement of the first division or all three divisions of the nerve, microvascular decompression is recommended. For older patients, for those not shown to have microvascular cross-compression, and for those not willing to undergo craniectomy, radiofrequency thermal rhizotomy is probably the next treatment of choice. Dogmatic recommendations are not appropriate in the absence of truly comparable data. Other techniques to be considered, if thermal rhizotomy is unsuccessful, include glycerol rhizotomy, balloon compression, partial sensory trigeminal rhizotomy, and peripheral neurectomy. The choice is given in no particular order. Patients offered such treatments require data on the track record of the relevant institution in performing that procedure. Stereotactic radiosurgery is still being evaluated for this condition. Because the associated morbidity is very low, it may become the treatment of choice for the elderly frail patient if longer-term follow-up establishes its continuing benefit.

Trigeminal neuralgia: a diagnostic challenge

A 38-year-old white woman came to the emergency department complaining of severe, unilateral jaw pain. She had consulted her primary care physician and dentist without achieving the correct diagnosis or significant relief of her symptoms. The emergency physician made the diagnosis of trigeminal neuralgia by obtaining a history of severe paroxysmal ipsilateral facial pain activated by numerous facial stimuli. A light stimulation of the trigger point precipitated the pain. Her pain relief from carbamazepine lent further credence to the diagnosis of trigeminal neuralgia and appropriate referral to a neurosurgeon. Pain relief was ultimately achieved for the last 8 months by a neurectomy of the right infraorbital nerve.

Results of treatment of trigeminal neuralgia by microvascular decompression of the Vth nerve at its root entry zone

Eighty five patients suffering from trigeminal neuralgia resistant to medical therapy underwent surgical treatment for relief of pain at the Department of Neurosurgery University Alexander Hospital Sofia from 1981 until 1997. Microvascular decompression at the root entry zone of the V(th) nerve has been performed using the technique of Jannetta. The operative exploration of the parapontine root entry zone disclosed neurovascular conflicts in 87.1% of the cases. They represented displacement and/or distortion, sometimes pressure grooves, discoloration, altered vascularity of the V(th) nerve. The analysis of early postoperative results have shown an excellent outcome in 90.6% of the cases, good in 3.5% and poor in 2.4% with mortality of 3.5% early in these series when no postoperative monitoring was available. The follow up study one year after surgery revealed 90.2% excellent and 3.7% good results and poor outcome and recurrences in 6.1% of the cases. Patients with long lasting trigeminal neuralgia, previous destructive procedures, venous compression, lack of convincible evidences for neurovascular conflicts had less favorable outcome or recurrences. In the last years partial sensory rhizotomy was performed in cases when no neurovascular conflicts were found out. Patients with unquestionable arterial compression leading to displacement associated with distortion and pressure grooves had excellent outcomes. Early recurrences were associated with missed pathology at the entry zones. During reexplorations for late recurrences new arterial compression was found in less than half of the cases.

Posterior fossa reexploration for persistent or recurrent trigeminal neuralgia or hemifacial spasm: surgical findings and therapeutic implications

OBJECTIVE

To evaluate the surgical findings and subsequent therapeutic implications of posterior fossa reexploration for persistent or recurrent trigeminal neuralgia (TN) or hemifacial spasm (HFS) after failed microvascular decompression (MVD).

METHODS

Between December 1975 and October 1996, the senior author performed 31 reexplorations for failure or recurrence after MVD: 23 for TN and 8 for HFS. Records were analyzed retrospectively for evidence of vascular compression in primary and secondary operations, other pertinent intraoperative findings, intraoperative therapeutic interventions, and postoperative results and complications.

RESULTS

The previously placed polyvinyl alcohol foam (Ivalon sponge; Unipoint Industries, High Point, NC) or Teflon implant (Teflon felt; CR Bard, Inc., Bard Implants Division, Billerica, MA) was found to be in good position in 100% of the patients (31 of 31 patients). New vascular compression from an arterial source was found in three patients during posterior fossa reexploration: one with TN and two with HFS. New vascular compression from a venous source was observed in one patient with HFS. A scarred Ivalon sponge or Teflon implant with apparent mass effect on the nerve root was identified in seven reexplorations. One bony source of compression was seen. No new compressive elements or other sources of root irritation were appreciated in 61% of reexplorations. Partial sensory trigeminal rhizotomy was performed in 83% of reexplorations for persistent or recurrent TN. Of eight patients undergoing reexploration for persistent or recurrent HFS, six sustained complications.

CONCLUSION

Recurrent vascular compression was seldom identified during posterior fossa reexploration for failed MVD in patients with persistent or recurrent TN or HFS. The previously placed Ivalon sponge or Teflon implant was consistently found to be in good position. Partial sensory trigeminal rhizotomy is an often effective alternative in cases of recurrent TN when neurovascular compression is not identified. However, because of the relatively high incidence of complications associated with reexploration, we recommend other ablative or medical treatments for most patients after failed MVD for TN or HFS.

Trigeminal numbness and tic relief after microvascular decompression for typical trigeminal neuralgia

OBJECTIVE

After most operative treatments for trigeminal neuralgia, long-term tic relief is closely correlated with postoperative numbness in the trigeminal distribution. Microvascular decompression (MVD) is proposed to relieve tic through a nontraumatic mechanism. We investigated the relationship between postoperative trigeminal numbness and tic relief in a large, prospectively followed cohort of patients treated with MVD for typical trigeminal neuralgia.

METHODS

Of 1204 patients who underwent MVD for typical tic during a 20-year period, 522 had single MVDs on a single side, had not undergone ablative trigeminal procedures before or after MVD, and were still being followed in 1994. In 1994, patients graded facial numbness using a questionnaire (response rate, 92%) with a 5-point scale. Multivariate Cox and logistic regression methods were used. The analyses were adjusted for the time that had passed between the performance of MVD and the completion of the questionnaire (minimum, 2 yr).

RESULTS

Seventeen percent of patients reported some degree of persistent facial numbness. Decompression of a vein at MVD (odds ratio, 2.5) and failure to find compression by the superior cerebellar artery (odds ratio, 2.0) independently predicted postoperative facial numbness, which in turn predicted postoperative burning and aching facial pain (odds ratio, 5.2-5.9). A trend toward worse outcome was noted in patients with numb faces (P = 0.3). Similar findings were noted in subgroups of patients in whom the superior cerebellar artery was decompressed at MVD (n = 381) and in whom a superior cerebellar artery with no vein was found (n = 120). In the latter subgroup, facial numbness (5.8% of patients) significantly predicted worse long-term outcome (P = 0.03).

CONCLUSION

We found no evidence that postoperative trigeminal numbness predicts relief of typical tic after MVD. Trigeminal numbness was related to operative findings at MVD and predicted postoperative burning and aching facial pain. To minimize postoperative facial dysesthesia, trauma to the trigeminal root during MVD should be avoided when possible.

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

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

Analysis of the relationship between long-term operative success and a transient or delayed operative side effect

OBJECTIVE

Investigators sometimes correlate the success of an operative procedure with the presence of an operative side effect that is thought to reflect the efficacy of the procedure in some way. When the prevalence of the side effect increases or decreases with time, this type of analysis can introduce a systematic bias.

METHODS

Monte Carlo-simulated patient cohorts with independently and randomly generated operative success and presence of side effects were generated. Kaplan-Meier analyses of operative success were stratified by the presence of side effects at various times after the "operation."

RESULTS

When the side effect (such as numbness after an ablative procedure) resolved during the study period in a significant proportion of patients, stratification by presence of the side effect at the end of the study period introduced a serious bias in favor of apparent better pain relief in patients without numbness. When the prevalence of the side effect increased with time (such as the requirement for a subsequent operation for radiation necrosis after brachytherapy or radiosurgical treatment of a glioma), the analysis was biased in favor of apparent longer survival for patients who experienced the side effect (i.e., those who required subsequent operations).

CONCLUSION

Analyses of operative success stratified by the presence of postoperative side effects with time-varying prevalence may be seriously biased and should be interpreted with caution.

Stereotactic radiosurgery for trigeminal neuralgia: a multiinstitutional study using the gamma unit

A multiinstitutional study was conducted to evaluate the technique, dose-selection parameters, and results of gamma knife stereotactic radiosurgery in the management of trigeminal neuralgia. Fifty patients at five centers underwent radio-surgery performed with a single 4-mm isocenter targeted at the nerve root entry zone. Thirty-two patients had undergone prior surgery, and the mean number of procedures that had been performed was 2.8 (range 1-7). The target dose of the radiosurgery used in the current study varied from 60 to 90 Gy. The median follow-up period after radiosurgery was 18 months (range 11-36 months). Twenty-nine patients (58%) responded with excellent control (pain free), 18 (36%) obtained good control (50%-90% relief), and three (6%) experienced treatment failure. The median time to pain relief was 1 month (range 1 day-6.7 months). Responses remained consistent for up to 3 years postradiosurgery in all cases except three (6%) in which the patients had pain recurrence at 5, 7, and 10 months. At 2 years, 54% of patients were pain free and 88% had 50% to 100% relief. A maximum radiosurgical dose of 70 Gy or greater was associated with a significantly greater chance of complete pain relief (72% vs. 9%, p = 0.0003). Three patients (6%) developed increased facial paresthesia after radiosurgery, which resolved totally in one case and improved in another. No patient developed other deficits or deafferentation pain. The proximal trigeminal nerve and root entry zone, which is well defined on magnetic resonance imaging, is an appropriate anatomical target for radiosurgery. Radiosurgery using the gamma unit is an additional effective surgical approach for the management of medically or surgically refractory trigeminal neuralgia. A longer-term follow-up review is warranted.

Trigeminal neuralgia versus atypical facial pain. A review of the literature and case report

Trigeminal neuralgia and atypical facial pain are common conditions of facial pain. Although these two pain conditions are classically well separated in textbooks, a straightforward diagnosis may not always be possible because of the overlapping clinical signs and symptoms. In this article, a comparison and differentiation between the clinical and diagnostic features of these two pain conditions are presented. The general characteristics, etiologic characteristics, pathophysiology, differential diagnostic criteria, and therapeutic options of trigeminal neuralgia and atypical facial pain are described. A case report demonstrates the difficulties that can arise in the diagnosis and differentiation between the two disease entities. The article underscores the responsibility clinicians have in correctly diagnosing and managing patients with facial pain conditions.

Post-rhizotomy periodontal atrophy

This report details the experience of two people who suffered a unique type of periodontal atrophy following trigeminal sensory rhizotomy. The cause is unknown but it may be the result of unintentional self-mutilation.

The medical and surgical management of trigeminal neuralgia

Trigeminal neuralgia is a paroxysmal and severely disabling facial pain. The diagnosis is usually made on the basis of a typical history and the exclusion of secondary causes. Initial management of the pain is medical. Carbamazepine is the drug of choice although some patients respond to other drugs including phenytoin, baclofen, sodium valproate and clonazepam. Surgical therapy should be considered if medical treatment fails or cannot be tolerated. Surgical options include peripheral or central (intracranial) procedures. Central procedures have greater morbidity and a significant mortality rate (approximately 1%) but the success rates are much greater. Physicians should be aware of the potential benefits of surgery but all patients should be advised carefully about the risks before informed consent is given.