Facial pain and the second edition of the International Classification of Headache Disorders

BACKGROUND: Recurrent or chronic facial pain may be a diagnostic challenge. Applying the diagnostic criteria of the second edition of the International Classification of Headache Disorders (ICHD-II) leaves a considerable number of patients unclassifiable. OBJECTIVE: The aim of this study was to establish and evaluate revised criteria of trigeminal neuralgia and persistent idiopathic facial pain. METHODS: Based on the diagnostic value of 12 clinical features of trigeminal neuralgia and 15 features of persistent idiopathic facial in 97 patients referred for facial pain to a neurological tertiary care centre we established revised criteria for persistent idiopathic facial pain and additional criteria for probable trigeminal neuralgia and probable idiopathic facial pain. RESULTS: Applying the newly proposed criteria reduced the number of patients with facial pain not classifiable by more than 50%. The new criteria improved the sensitivity, particularly in idiopathic facial pain and did not cause a relevant decrease in specificity compared to ICHD-II. CONCLUSION: This study suggests that amendments to the ICHD-II criteria improve the diagnostic classification of facial pain.     

Pregabalin for Postherpetic Neuralgia: Placebo-Controlled Trial of Fixed and Flexible Dosing Regimens on Allodynia and Time to Onset of Pain Relief

Time to onset of pain relief and improvement in allodynia in 269 patients with postherpetic neuralgia was examined in a 4-week randomized trial comparing flexibly dosed pregabalin (150–600 mg/d), fixed-dose pregabalin (300 mg/d), and placebo. For each patient with clinically meaningful pain reduction (≥30%) at end point, onset of pain relief was defined as the first study day on which a patient reported ≥1-point reduction in pain relative to baseline. Average dose achieved was 396 mg/d in the flexible-dose group compared with 295 mg/d in the fixed-dose group. Median pain relief onset times were 3.5 days (flexible-dose), 1.5 days (fixed-dose), and >4 weeks (placebo). Compared with placebo, significantly more patients in both pregabalin treatment groups achieved ≥30% and ≥50% pain reduction at end point. Almost 95% of patients had brush-evoked allodynia, with 68% having moderate to severe allodynia (≥40/100 mm). At baseline, pain and allodynia were highly correlated. Independent of treatment assignment, improvement in pain and improvement in allodynia were significantly correlated. Allodynia could serve as a useful surrogate outcome measure in future studies. Pregabalin was significantly better than placebo in alleviating allodynia (flexible-dose reduction, 26 mm; fixed-dose, 21 mm; placebo, 12 mm). Discontinuation rates due to adverse events were more frequent in the fixed-dose group.PerspectiveA flexible-dose regimen reduces discontinuations, facilitates higher final doses, and results in a slightly greater pain relief. Allodynia (touch-evoked pain) can be of disabling severity and is present in nearly all patients with postherpetic neuralgia. Allodynia severity is correlated with pain severity and improvement in allodynia is correlated with clinical response.     

Occipital nerve block is effective in craniofacial neuralgias but not in idiopathic persistent facial pain

Occipital nerve block (ONB) has been used in several primary headache syndromes with good results. Information on its effects in facial pain is sparse. In this chart review, the efficacy of ONB using lidocaine and dexamethasone was evaluated in 20 patients with craniofacial pain syndromes comprising 8 patients with trigeminal neuralgia, 6 with trigeminal neuropathic pain, 5 with persistent idiopathic facial pain and 1 with occipital neuralgia. Response was defined as an at least 50% reduction of original pain. Mean response rate was 55% with greatest efficacy in trigeminal (75%) and occipital neuralgia (100%) and less efficacy in trigeminal neuropathic pain (50%) and persistent idiopathic facial pain (20%). The effects lasted for an average of 27 days with sustained benefits for 69, 77 and 107 days in three patients. Side effects were reported in 50%, albeit transient and mild in nature. ONBs are effective in trigeminal pain involving the second and third branch and seem to be most effective in craniofacial neuralgias. They should be considered in facial pain before more invasive approaches, such as thermocoagulation or vascular decompression, are performed, given that side effects are mild and the procedure is minimally invasive.     

Pain Responder Analysis: Use of Area Under the Curve to Enhance Interpretation of Clinical Trial Results

Interpretation of results on patient-reported pain outcomes from clinical trials should be meaningful to patients and healthcare providers. This study applied an area-under-the-curve (AUC) analysis to responder profiles in a clinical trial of pregabalin for the treatment of fibromyalgia (FM). Data were from a 14-week, randomized, placebo-controlled trial of pregabalin (300, 450, or 600 mg/day) for the treatment of FM in patients meeting American College of Rheumatology criteria for FM and with a baseline pain score of at least 40 mm on the 100-mm pain visual analogue scale. Pain was evaluated in a daily diary by patients using an 11-point numeric rating scale (0 = no pain, 10 = worst possible pain). Response profiles on pain improvement scores and their differences between pregabalin and placebo were assessed using the AUC (derived using the trapezoidal rule) from the responder curve (vertical axis, proportion of subjects; horizontal axis, minimum percent improvement in pain). The AUC can be interpreted as if all responders were improved by the same percentage equal to the AUC divided by 100. The AUCs (2,100 for placebo, and 2,944, 3,170, and 3,349 for pregabalin 300, 450, and 600 mg, respectively) can be considered as if every responder improved by 21, 29, 31, and 33.5% in the responder's respective treatment group. Pain improvement was significantly better with pregabalin ( P  < 0.05), with pregabalin responders improving by 8.4% (300 mg/day), 10.7% (450 mg/day), and 12.5% (600 mg/day) more than placebo responders. This novel approach demonstrates that responder profiles can provide an enhanced interpretation of pain outcomes for patient care and symptom management.     

Patient-reported outcomes in subjects with painful trigeminal neuralgia receiving pregabalin: evidence from medical practice in primary care settings

Effects of pregabalin (PGB) on patient-reported health outcomes were assessed in 65 PGB-naive subjects with trigeminal neuralgia refractory to previous analgesic therapy in a prospective, multicentre observational study carried out in primary care. Twelve weeks' monotherapy with PGB ( n  = 36) or add-on ( n  = 29), reduced baseline intensity of pain by a mean ± s . d . of −40.0 ± 22.1 mm [−55.4%, effect size (ES) 2.32; P  < 0.0001] with 59.4% of responders (pain reduction ≥ 50%), and produced 34.6 ± 29.3 additional days with no/mild pain. Anxiety/depression symptoms decreased by −3.8 ± 3.5 and −4.5 ± 4.2 points (ES 0.95 and 1.02; P  < 0.0001), respectively. PGB improved sleep by −17.9 ± 19.6 points (ES 1.18; P  < 0.0001) and improved patient functioning (Sheehan Disability Index) by decreasing overall scoring by −8.6 ± 5.9 points (ES 1.59; P  < 0.0001). Health state (EQ-5D) increased by 31.6 ± 22.2 mm (ES 1.67; P  < 0.0001), with 0.0388 ± 0.0374 gained quality-adjusted life-years. In spite of the small sample size, results support the effectiveness of PGB for the improvement in pain and related health symptoms.     

Pregabalin for relief of neuropathic pain associated with diabetic neuropathy: A randomized,double‐blind study

Seven published, randomized, placebo‐controlled clinical trials with pregabalin have shown robust efficacy for relief of neuropathic pain from DPN and PHN. An investigation of the efficacy and safety of twice daily pregabalin enrolled 395 adults with painful DPN for ≥1 year in a 12‐week, double‐blind, placebo‐controlled trial. Patients were randomized to placebo, 150, 300, or 600mg/day pregabalin (n=96, 99, 99, and 101). Primary efficacy measure was change from baseline in endpoint mean pain score from patients’ daily pain diaries. Secondary efficacy measures included pain‐related sleep‐interference scores, Patient and Clinical Global Impressions of Change (PGIC, CGIC), and the EuroQOL Health Utilities Index (EQ‐5D). Statistically significant reduction in pain was observed in patients receiving pregabalin 600mg/day, and 46% of patients treated with 600mg/day pregabalin reported ≥50% improvement in mean pain scores from baseline (vs 30% of placebo patients, p=0.036). Number needed to treat to achieve such response was 6.3. Pregabalin 600mg/day was significantly superior to placebo in improving pain‐related sleep‐interference scores (p=0.003), PGIC (p=0.021), and CGIC (p=0.009). (Neither pregabalin 150 nor 300mg/day separated from placebo on these measures, largely because of an atypically large placebo response in one country representing 42% of patients.) All pregabalin dosages were superior to placebo in improving EQ‐5D utility scores (all p≥0.0263 vs placebo). Pregabalin was well tolerated at all dosages; adverse events were generally mild to moderate. Number needed to harm (discontinuation because of adverse events) was 10.3 for pregabalin 600mg/day.     

A Cost-Consequences Analysis of the Effect of Pregabalin in the Treatment of Painful Radiculopathy under Medical Practice Conditions in Primary Care Settings

Purpose:   To analyze the effect of pregabalin (PGB) on pain relief, longitudinal utilization of health and nonhealth resources and derived costs in patients with refractory painful radiculopathy under routine medical practice in primary care settings (PCS).
Methods:   Subjects over 18 years of age with painful radiculopathy (cervical/lumbar) refractory to at least one previous analgesic therapy were included in a prospective, naturalistic, 12-week study. Consumption of resources included both health-care and nonhealth-care resources. Pain severity was measured using the Short Form of the McGill Pain Questionnaire.
Results:   One thousand three hundred and four PGB-naive patients (55.8% women, 56.7 [12.9] years) were analyzed: 473 (36%) switched to monotherapy with PGB (PGBm), 676 (52%) received add-on therapy with PGB (PGBadd-on), and in 155 patients (12%) the previous treatment was replaced by a schedule not including PGB (non-PGB). As compared with the non-PGB, both PGBm and PGBadd-on schedules showed a significantly greater reduction of pain severity (36.1%, 56.1%, and 49.6% reductions, respectively, P  < 0.001 between groups) and consumption of resources. Additional costs of drugs, particularly in the PGB subgroups (€15.4, €148.6 and €145.3, respectively, P  < 0.001) were offset by significantly greater reductions of all other components of health-care and nonhealth-care cost, thus resulting in a substantial reduction of total cost: €1,203.3, €1,423.2, and €1,429.2, respectively ( P  < 0.001).
Conclusion:   In PCS, either PGBadd-on or PGBm under routine medical practice was associated with pain alleviation leading to significant longitudinal reductions in resource use and total costs compared with non-PGB-therapy in subjects with painful refractory cervical or lumbar radiculopathy.     

Pregabalin: a novel gamma-aminobutyric acid analogue in the treatment of neuropathic pain, partial-onset seizures, and anxiety disorders

BACKGROUND: The US Food and Drug Administration (FDA) approved pregabalin in December 2004 for the treatment of neuropathic pain associated with diabetic peripheral neuropathy and postherpetic neuralgia. Pregabalin is the first drug approved in the United States and in Europe for both conditions. In June 2005, pregabalin was approved as an adjunctive treatment in adults with partial-onset seizures. The FDA currently is considering the approval of pregabalin as adjunctive therapy in adults with generalized anxiety disorder (GAD) or social anxiety disorder (SAD). OBJECTIVES: The goals of this review were to summarize the pharmacology, pharmacokinetics, efficacy, and tolerability of pregabalin; review its approved uses in the management of neuropathic pain and refractory partial-onset seizures; and investigate its potential use in patients with GAD or SAD. METHODS: Relevant English-language literature was identified through a search of MEDLINE (1993-June 2006) and International Pharmaceutical Abstracts (2000-June 2006). The search terms included pregabalin, Lyrica, S-(+)-3 isobutyl-gaba, PN, DPN, diabetic peripheral neuropathy, PHN, postherpetic neuralgia, partial seizures, epilepsy, generalized anxiety disorder, and CI-1008. RESULTS: In 4 clinical trials in a total of 1068 patients with diabetic peripheral neuropathy, the patients receiving pregabalin 300 to 600 mg/d had significantly greater improvement in mean pain scores than placebo recipients (P < or = 0.01). Patients with postherpetic neuralgia receiving pregabalin 450 to 600 mg/d had significantly greater improvement in relief of pain and pain-related sleep interference than placebo recipients (P < or = 0.002). Patients with refractory partial-onset seizures who received pregabalin 150 to 600 mg/d (divided into 2 or 3 doses) concomitantly with antiepileptic drugs had significantly fewer seizures than placebo recipients (P < or = 0.001). In the 3 studies that evaluated the efficacy of pregabalin in patients with GAD or SAD, the patients receiving pregabalin 200 to 600 mg/d (divided into 2 or 3 daily doses) had a significantly greater reduction in mean pain scores on the Hamilton Anxiety Scale than placebo recipients (P < or = 0.01). Across all the reviewed clinical trials, the most commonly reported adverse effects (AEs) were those affecting the central nervous system, including somnolence (< or =50%), dizziness (< or =49%), and headache (< or =29%). AEs resulted in withdrawal from the study in < or =32% of patients. CONCLUSIONS: Pregabalin appears to be an effective therapy in patients with diabetic peripheral neuropathy, postherpetic neuralgia, and adults with refractory partial-onset seizures. The available data suggest that pregabalin may be beneficial as an adjunctive therapy in adult patients with GAD or SAD.     

Pregabalin in patients with central neuropathic pain: a randomized, double-blind, placebo-controlled trial of a flexible-dose regimen

The effective treatment of patients suffering from central neuropathic pain remains a clinical challenge, despite a standard pharmacological approach in combination with anticonvulsants and antidepressants. A randomized, double-blinded, placebo-controlled trial evaluated the effects of pregabalin on pain relief, tolerability, health status, and quality of life in patients with central neuropathic pain caused by brain or spinal cord injuries. At baseline and 4 weeks after the start of treatment subjects were evaluated with standard measures of efficacy: pain intensity measured by visual analog scale, health status (Pain Disability Index and EQ-5D) and quality of life (SF-36). Forty patients received escalating doses of either pregabalin (150, 300, and 600 mg/day) or matching placebo capsules. In both groups, patients started with 1 capsule per day (either 150 mg of pregabalin or placebo). If pain relief was insufficient, patients were titrated to a higher dose. There was a statistically significant decrease in mean pain score at endpoint for pregabalin treatment, compared with placebo (P = 0.016). Follow-up observation showed no significant difference in Pain Disability Index scores between the two groups. The pregabalin group, however, showed a statistically significant improvement for the EQ-5D. Pregabalin treatment led to a significant improvement in the bodily pain domain of the SF36. In the other domains, more favorable scores were reported without reaching statistical significance. Pregabalin, in a flexible-dose regime, produced clinically significant reductions in pain, as well as improvements in health status in patients suffering from severe central neuropathic pain.     

伽玛刀治疗原发性三叉神经痛疗效观察

目的 探讨伽玛刀治疗原发性三又神经痛的疗效.方法 2003年1月至2008年3月,我院应用伽玛刀治疗原发性三又神经痛120例;治疗靶点为三叉神经根,用4 mm准直器,靶点中心计量为80～90 Gy.疗效评估采用患者自我报告疼痛的控制程度及药物用量的变化.结果 所有患者进行了随访,平均随访期(20.0±4.5)个月.本组病例中治愈69例(57.5%);显效34例(28.3%)、有效12例(10.0%)、无效5例(4.2%);总有效率为95.8%.5例患者疼痛复发后行其他治疗.83例患者(69.2%)曾出现一过性、局限性的面部麻木.14例患者(11.7%)在疼痛缓解后留下持续性的面部麻木;部分患者还伴有味觉减退、口嚼无力等主诉.结论 伽玛刀治疗原发性三又神经痛能够显著缓解疼痛、提高生活质量,不良反应发生率较低:是一种较为理想的治疗方法.     

Efficacy of pregabalin in neuropathic pain evaluated in a 12-week, randomised, double-blind, multicentre, placebo-controlled trial of flexible- and fixed-dose regimens

Pregabalin binds with high affinity to the alpha2-delta subunit protein of voltage-gated calcium channels and, thereby, reduces release of excitatory neurotransmitters. This 12-week randomised, double-blind, multicentre, placebo-controlled, parallel-group study evaluated the efficacy and safety of pregabalin in patients with chronic postherpetic neuralgia (PHN) or painful diabetic peripheral neuropathy (DPN). Patients were randomised to placebo (n=65) or to one of two pregabalin regimens: a flexible schedule of 150, 300, 450, and 600 mg/day with weekly dose escalation based on patients' individual responses and tolerability (n=141) or a fixed schedule of 300 mg/day for 1 week followed by 600 mg/day for 11 weeks (n=132). Both flexible- and fixed-dose pregabalin significantly reduced endpoint mean pain score (primary outcome) versus placebo (P=0.002, P<0.001) and were significantly superior to placebo in improving pain-related sleep interference (P<0.001). The most common adverse events (AEs) for pregabalin-treated patients were dizziness, peripheral oedema, weight gain (not affecting diabetes control), and somnolence. These results are consistent with previous studies' demonstrating pregabalin's efficacy, tolerability, and safety for treatment of chronic neuropathic pain associated with DPN or PHN. Pregabalin dosing aimed at optimal balance of efficacy and tolerability provides significant pain relief and may reduce risks for AEs and therapy discontinuation.     

Facial pain in a neurological tertiary care centre--evaluation of the International Classification of Headache Disorders

The aim of this study was to examine the diagnostic spectrum of facial pain and to evaluate the clinical features relevant to the differential diagnosis in a neurological tertiary care centre. This is the first investigation comparing the first with the second edition of the International Classification of Headache Disorders (ICHD-I, ICHD-II) in consecutively referred patients comprising a broad spectrum of disorders without restricting the inclusion to certain diagnoses. Studying 97 consecutive patients referred for facial pain, we found trigeminal neuralgia or other types of cranial neuralgia in 38% and 39% according to ICHD-I and ICHD-II, respectively; persistent idiopathic facial pain was diagnosed in 27% and 21%, respectively. The proportion of patients who could not be classified was 24% in ICHD-I and 29% in ICHD-II. Six per cent of the patients had cluster headache or chronic paroxysmal hemicrania, the remaining 5% had various other disorders. The agreement between ICHD-I and ICHD-II was very good to perfect. In ICHD-II, sensitivity and specificity were similar to ICHD-I, the specificity and negative predictive value were imrpoved in single features of trigeminal neuralgia, but were widely unchanged in persistent idiopathic facial pain. The number of patients who could not be classified was larger in ICHD-II than in ICHD-I. Modifying the diagnostic criteria for different types of facial pain, in particular changes in the criteria of persistent idiopathic facial pain, might be helpful in reducing the number of patients with unclassifiable facial pain.     

Neurosurgical therapy of facial neuralgias

INTRODUCTION: Neuralgias of the face, especially trigeminal neuralgia and glossopharyngeal neuralgia are indications for surgical interventions after failed medical therapy. In contrast to other forms of headache or atypical facial pain, where surgical measures are considered to be contraindicated, percutaneous procedures or microvascular decompression are able to produce immediate and longstanding pain relief. Careful preoperative evaluation is essential to confirm the clinical diagnosis and to rule out other causes as multiple sclerosis or tumors afflicting the cranial nerves. The following study will summarize the common surgical techniques and their role considering a mechanism-based therapy as well as document long-term results of these measures. METHODS: Between 1977 and 1997 316 thermo-controlled radiofrequency trigeminal rhizotomies (TK) and 379 microvascular decompressions (MVD) were performed in our hospital to treat trigeminal neuralgia; additional 6 MVDs for glossopharyngeal neuralgia and one MVD of the intermediate facial nerve were carried out. Questionnaires were sent out to all patients still living in 1981, 1982, 1992 and 1998. For all other patients, interviews with relatives or the general practitioners were conducted. A retrospective analysis of postoperative pain relief was performed using Kaplan-Meier curves at the latest follow-up. Additionally 80 patients underwent careful quantitative sensory testing with Von-Frey-hairs. RESULTS: 225 patients who underwent microvascular decompression and 206 with radiofrequency trigeminal rhizotomies were further analyzed. There was a 50% risk for pain recurrence two years after radiofrequency rhizotomy. On the other hand 64% of patients who underwent microvascular decompression remained painfree 20 years postoperatively. Patients with microvascular decompression without sensory deficit were painfree significantly longer than patients with postoperative hypesthesia. DISCUSSION: Etiology and pathogenesis of facial neuralgias are far from understood despite several hypotheses. Based on current models there is no explanation for the immediate pain relief especially after microvascular decompression. Some authors even discuss surgical trauma as the only cause for postoperative pain relief.     

Pharmacotherapy of orofacial pain

OBJECTIVES. Pharmacotherapy of chronic orofacial pain is unsatisfactory. Here we set out to prepare a systematic review of randomized controlled clinical trials (RCTs) on pharmacotherapy of facial pain. METHODS. The diagnostic groups "temporomandibular disorders" (TMDs), "atypical facial pain", and "trigeminal neuralgia" were included. RCTs published between 1966 and August 2001 were identified by Medline search, from review articles, and from the Cochrane and Bandolier databases. The quality of the trials was judged according to established criteria. Good or excellent pain reduction or >50% pain reduction were used as endpoints for successful treatment. Numbers needed to treat (NNTs) and their 95% confidence intervals were calculated where dichotomous data were available. RESULTS. Twelve studies were identified for the TMDs, 11 for trigeminal neuralgia, four for atypical facial pain. Many studies had methodological problems and small numbers of patients. There was sufficient evidence of efficacy of carbamazepin in trigeminal neuralgia, also for baclofen and lamotrigine. In the TMD studies, there was evidence of a moderate effect of muscle relaxants/tranquilizers. Two studies of atypical facial pain showed a moderate effect of antidepressants. CONCLUSIONS. Apart from studies in trigeminal neuralgia, there is little evidence of efficacy of pharmacotherapy in orofacial pain. High quality studies with sufficient numbers of patients using operational definitions of disease entities are warranted.     

The evidence for pharmacological treatment of neuropathic pain

Randomized, double-blind, placebo-controlled trials on neuropathic pain treatment are accumulating, so an updated review of the available evidence is needed. Studies were identified using MEDLINE and EMBASE searches. Numbers needed to treat (NNT) and numbers needed to harm (NNH) values were used to compare the efficacy and safety of different treatments for a number of neuropathic pain conditions. One hundred and seventy-four studies were included, representing a 66% increase in published randomized, placebo-controlled trials in the last 5 years. Painful poly-neuropathy (most often due to diabetes) was examined in 69 studies, postherpetic neuralgia in 23, while peripheral nerve injury, central pain, HIV neuropathy, and trigeminal neuralgia were less often studied. Tricyclic antidepressants, serotonin noradrenaline reuptake inhibitors, the anticonvulsants gabapentin and pregabalin, and opioids are the drug classes for which there is the best evidence for a clinical relevant effect. Despite a 66% increase in published trials only a limited improvement of neuropathic pain treatment has been obtained. A large proportion of neuropathic pain patients are left with insufficient pain relief. This fact calls for other treatment options to target chronic neuropathic pain. Large-scale drug trials that aim to identify possible subgroups of patients who are likely to respond to specific drugs are needed to test the hypothesis that a mechanism-based classification may help improve treatment of the individual patients.     

Paracetamol with and without codeine in acute pain: a quantitative systematic review

In order to assess the analgesia obtained from single oral doses of paracetamol alone and in combination with codeine in postoperative pain, we conducted a systematic review of randomised controlled trials. We found 31 trials of paracetamol against placebo with 2515 patients, 19 trials of paracetamol plus codeine against placebo with 1204 patients and 13 trials of paracetamol plus codeine against the same dose of paracetamol with 874 patients. Pain relief information was extracted, and converted into dichotomous information (number of patients with at least 50% pain relief). Wide variations in responses to placebo (0–72%) and active drug (3–89%) were observed. In postoperative pain states paracetamol 1000 mg alone against placebo had an number-needed-to-treat (NNT) of 3.6 (3.0–4.4) and paracetamol 600/650 mg alone an NNT of 5.0 (4.1–6.9). Paracetamol 600/650 mg plus codeine 60 mg against placebo had a better NNT of 3.1 (2.6–3.8), with no overlap of 95% confidence intervals with paracetamol 600/650 mg alone. In direct comparisons of paracetamol plus codeine with paracetamol alone the additional analgesic effect of 60 mg of codeine added to paracetamol was 12 extra patients in every 100 achieving at least 50% pain relief. In indirect comparisons of each with placebo it was 14 extra patients per 100. This was an NNT for adding codeine 60 mg of 9.1 (5.8–24). The results confirm that paracetamol is an effective analgesic, and that codeine 60 mg added to paracetamol produces worthwhile additional pain relief even in single oral doses.     

Studies on the operative outcomes and mechanisms of microvascular decompression in treating typical and atypical trigeminal neuralgia

OBJECTIVE: To evaluate the operative outcomes and mechanisms of microvascular decompression in treating typical and atypical trigeminal neuralgia. METHODS: A group of 45 patients with typical trigeminal neuralgia and 17 patients with atypical trigeminal neuralgia treated by micro-vascular decompression from 2000 to 2002 were reviewed, including their clinical presentations, operative findings, and outcomes. RESULTS: Of 45 patients with typical trigeminal neuralgia, the mean duration was 3.1 years, and the mean age of pain onset was 60.3 years. Single trigeminal division was involved in 20 patients (44.4%), and 2 or 3 divisions were involved in the other 25 patients (55.6%). During the operation, artery compression was found in 39 patients (86.7%), and the combined artery and venous compression was found in 6 patients (13.3%). Postoperatively, complete pain relief was achieved in 44 patients (97.8%), and significant pain relief was achieved in 1 patient (2.2%). As for 17 patients with atypical trigeminal neuralgia, the mean duration and the mean age of pain onset was 8.7 years and 55.5 years, respectively. Two or 3 trigeminal divisions were involved in all of these patients. During operation, artery compression occurred in 10 patients (58.8%), and the combined artery and venous compression was found in 7 patients (41.2%). Postoperatively, complete pain relief was achieved in 5 patients (29.4%), and partial pain relief was achieved in 10 patients (58.8%), and 2 patients showed no response to microvascular decompression. CONCLUSIONS: The operative outcome of microvascular decompression in patients with typical trigeminal neuralgia was better than that of patients with atypical trigeminal neuralgia, which perhaps related to short duration, late onset of pain, limited distribution, artery compression, and complete operative decompression.     

The use of botulinum toxin for the treatment of chronic facial pain.

An open label pilot study was conducted to evaluate efficacy of botulinum toxin injections for the treatment of patients with chronic facial pain seeking tertiary care at a pain clinic. Diagnoses included temporomandibular joint syndrome, postsurgical pain syndromes, essential headache, and idiopathic trigeminal neuralgia. Thirty-three (75%) of 44 patients favorably responded, including 8 of 11 patients with trigeminal neuralgia. The duration of beneficial effect ranged from 2 to 4 months, and all responding patients desired further injections. Complications were mild and included temporary facial asymmetry and weakness secondary to neuromuscular effects of botulinum toxin. Doses ranged from 25 to 75 LD 50 units with Hall strain-derived botulinum toxin type A. A small degree of facial edema during pain or erythema seemed to have predictive value when categorically evaluated against response.     

Surgical treatment of chronic cluster headache

Chronic cluster headache, also known as chronic migrainous neuralgia, is frequently unresponsive to medical management. Although neuronal factors may be involved in the pathogenesis of this form of recurrent hemicranial pain, vasodilatation within the distribution of the trigeminal nerve is believed to be important. Attempts to provide relief by surgical means have primarily involved interruption of the vasodilator pathways of the greater superficial petrosal nerve and the sphenopalatine ganglion. A more direct approach of interrupting the pain pathways of the trigeminal nerve has been attempted sporadically for more than 50 years. Recent interest in the role of substance P in the production of pain in cluster headache suggests that trigeminal ablative procedures might have a dual role in the relief of medically intractable cases. Among 26 patients who underwent posterior fossa trigeminal sensory rhizotomy or percutaneous radio-frequency trigeminal gangliorhizolysis at our institution, relief of pain was excellent in 14 (54%), fair to good in 4 (15%), and poor in 8 (31%).     

Cryoneurolysis of alveolar nerves for chronic dental pain: A new technique and a case series

Background

Chronic neuropathic dental pain has a poor prognosis with a low chance of significant spontaneous improvement. Local or oral therapies may be efficient, however short in terms of duration with potential side effects. Cryoneurolysis has been described to prevent acute postoperative pain or to treat some chronic pain conditions; however, application to dental orofacial pain has not been reported so far.

Case Series

Following a positive diagnostic block on the corresponding alveolar nerve, neuroablation was performed using a cryoprobe on three patients suffering from persistent pain after a dental extraction and 1 after multiple tooth surgeries. The effect of treatment was assessed using a Pain Numeric Rating Scale (NRS) and determined by changes in medication dosage and quality of life at day 7 and 3 months. Two patients experienced more than 50% of pain relief at 3 months, 2 by 50%. One patient was able to wean off pregabalin medication, one decreased amitriptyline by 50%, and one decreased tapentadol by 50%. No direct complications were reported. All of them mentioned improvement in sleep and quality of life.

Conclusion

Cryoneurolysis on alveolar nerves is a safe and easy-to-use technique allowing prolonged neuropathic pain relief after dental surgery.