Atypical Facial Pain: a Comprehensive, Evidence-Based Review

The long-term outcome of CT-guided radiofrequency ablation of the peripheral branches of the trigeminal nerve in trigeminal neuralgia

Radiofrequency thermocoagulation (RFTC) of the peripheral branches of the trigeminal nerve has been used for trigeminal neuralgia. However, the long-term outcomes of radiofrequency thermocoagulation have not been established. To evaluate the long-term efficacy of RFTC of peripheral branches in patients with refractory trigeminal neuralgia. A retrospective cohort study was conducted in a comprehensive medical center in China. Patients who underwent radiofrequency thermocoagulation of peripheral branches for refractory trigeminal neuralgia from May 2014 to March 2021 were included for analysis. A total of 84 patients with refractory trigeminal neuralgia underwent 105 procedures. BNI I-II which represents treatment success was achieved in 76/84 (90%) patients and 93/105 (89%) procedures. During follow-up, BNI I and II were maintained in 64/76 (84%), 40/73 (55%), 20/67 (30%), 17/65 (26%), 12/61 (20%), and 8/58 (14%) of patients at 1, 2, 3, 4, 5, and 6 years, after the first procedure, respectively. For all the 105 procedures, BNI I and II were maintained in 68/93 (73%), 41/89(46%), 22/82(27%), 15/79 (19%), 8/74 (11%), and 3/72 (4%) at 1, 2, 3, 4, 5, and 6 years, respectively. There is no significant difference between the first and repeat thermocoagulation in terms of immediate (90% vs. 81%, P=0.140) and long-term efficacies (24 months vs.18 months, P=0.266). Radiofrequency thermocoagulation resulted in better long-term outcomes in patients with typical purely paroxysmal pain (24 months vs. 11 months, P=0.033). Radiofrequency ablation of the peripheral branches of the trigeminal nerve might be a safe and effective method in the treatment of refractory trigeminal neuralgia.

Advancements in Understanding and Classifying Chronic Orofacial Pain: Key Insights from Biopsychosocial Models and International Classifications (ICHD-3, ICD-11, ICOP)

In exploring chronic orofacial pain (COFP), this review highlights its global impact on life quality and critiques current diagnostic systems, including the ICD-11, ICOP, and ICHD-3, for their limitations in addressing COFP's complexity. Firstly, this study outlines the global burden of chronic pain and the importance of distinguishing between different pain types for effective treatment. It then delves into the specific challenges of diagnosing COFP, emphasizing the need for a more nuanced approach that incorporates the biopsychosocial model. This review critically examines existing classification systems, highlighting their limitations in fully capturing COFP's multifaceted nature. It advocates for the integration of these systems with the DSM-5's Somatic Symptom Disorder code, proposing a unified, multidisciplinary diagnostic approach. This recommendation aims to improve chronic pain coding standardization and acknowledge the complex interplay of biological, psychological, and social factors in COFP. In conclusion, here, we highlight the need for a comprehensive, universally applicable classification system for COFP. Such a system would enable accurate diagnosis, streamline treatment strategies, and enhance communication among healthcare professionals. This advancement holds potential for significant contributions to research and patient care in this challenging field, offering a broader perspective for scientists across disciplines.

Deep Brain Stimulation for Chronic Facial Pain: An Individual Participant Data (IPD) Meta-Analysis

Despite available, advanced pharmacological and behavioral therapies, refractory chronic facial pain of different origins still poses a therapeutic challenge. In circumstances where there is insufficient responsiveness to pharmacological/behavioral therapies, deep brain stimulation should be considered as a potential effective treatment option. We performed an individual participant data (IPD) meta-analysis including searches on PubMed, Embase, and the Cochrane Library (2000–2022). The primary endpoint was the change in pain intensity (visual analogue scale; VAS) at a defined time-point of ≤3 months post-DBS. In addition, correlation and regression analyses were performed to identify predictive markers (age, duration of pain, frequency, amplitude, intensity, contact configuration, and the DBS target). A total of seven trials consisting of 54 screened patients met the inclusion criteria. DBS significantly reduced the pain levels after 3 months without being related to a specific DBS target, age, contact configuration, stimulation intensity, frequency, amplitude, or chronic pain duration. Adverse events were an infection or lead fracture (19%), stimulation-induced side effects (7%), and three deaths (unrelated to DBS—from cancer progression or a second stroke). Although comparable long-term data are lacking, the current published data indicate that DBS (thalamic and PVG/PAG) effectively suppresses facial pain in the short-term. However, the low-quality evidence, reporting bias, and placebo effects must be considered in future randomized-controlled DBS trials for facial pain.

Supplementing transcranial direct current stimulation to local infiltration series for refractory neuropathic craniocephalic pain: A randomized controlled pilot trial

Background

Some patients with neuralgia of cranial nerves with otherwise therapy-refractory pain respond to invasive therapy with local anesthetics. Unfortunately, pain regularly relapses despite multimodal pain management. Transcranial direct current stimulation (tDCS) may prolong pain response due to neuro-modulatory effects.

Methods

This controlled clinical pilot trial randomized patients to receive anodal, cathodal or sham-tDCS stimulation prior to local anesthetic infiltration. Pain attenuation, quality-of-life and side effects were assessed and compared with historic controls to estimate effects of tDCS stimulation setting.

Results

Altogether, 17 patients were randomized into three groups with different stimulation protocols. Relative reduction of pain intensity in per protocol treated patients were median 73%, 50% and 69% in anodal, cathodal and sham group, respectively (p = 0.726). Compared with a historic control group, a lower rate of responders with 50% reduction of pain intensity indicates probable placebo effects (OR 3.41 stimulation vs. non-stimulation setting, NNT 3.63). 76.9% (n = 10) of tDCS patients reported mild side-effects. Of all initially included 17 patients, 23.5% (n = 4) withdrew their study participation with highest proportion in the cathodal group (n = 3). A sample size calculation for a confirmatory trial revealed 120 patients using conservative estimations.

Discussion

This pilot trial does not support series of anodal tDCS as neuro-modulatory treatment to enhance pain alleviation of local anesthetic infiltration series. Notably, results may indicate placebo effects of tDCS settings. Feasibility of studies in this population was limited due to relevant drop-out rates. Anodal tDCS warrants further confirmation as neuro-modulatory pain treatment option.

Effect of neuropathic pain on sphenopalatine ganglion block responses in persistent idiopathic facial pain

OBJECTIVES

Management of persistent idiopathic facial pain (PIFP) can be challenging. Sphenopalatine ganglion (SPG) has been the target for the interventional treatment of many facial pain syndromes. However, possible factors that may affect SPG block success are unknown. It was aimed to investigate the effect of neuropathic pain on SPG block outcomes in PIFP, which includes a heterogeneous patient group.

METHODS

All of the patients underwent fluoroscopy-guided SPG block with an injection of 40 mg of 2% lidocaine and 8 mg of dexamethasone. The patients were assigned to 2 groups according to existence of neuropathic pain determined with the DN4 questionnaire score: 19 patients with neuropathic pain (Group 1) and 15 patients without neuropathic pain (Group 2). Preprocedural and postprocedural Visual Analog Scale (VAS) scores were compared between the 2 groups.

RESULTS

The mean age of the patients was 47.65 ± 6.50 years. The average pain duration was 52.95 ± 34.81 weeks. A significantly greater decrease was detected in the VAS scores at 1 week (p = 0.036) and 1 month (p < 0.001) in Group 1 when compared to Group 2. Moreover, the proportion of patients with >50% improvement in the VAS scores at 1 week (p = 0.012) and 1 month (P = 0.017) was significantly lower in Group 1 than in Group 2.

DISCUSSION

SPG block appears as a safe, effective, and rapid method to treat PIFP, especially in cases with neuropathic pain. Neuropathic pain may be a predictor for pain relief in interventional procedures targeting SPG in the treatment of PIFP.

Pregestational neurological disorders among women of childbearing age—Nationwide data from a 13-year period in Hungary

Objectives

Comprehensive statistics evaluating pregnancies complicated by various medical conditions are desirable for the optimization of prenatal care and for improving maternal and fetal outcomes. The main objective of our study was to assess pregnancies during a 13-year study period with accompanying pregestational neurological disorders in medical history on a nationwide level.

Methods

In the framework of the NEUROHUN 2004–2017 project utilizing medical reports submitted for reimbursement purposes to the National Health Insurance Fund, we included women with at least one labor during 2004–2016 who had at least one pregestational diagnosis of a neurological disorder received within this time frame prior to their first pregnancy during the studied period. Three-digit codes from the 10^th International Classification of Diseases (ICD) were used for the identification and classification of neurological and obstetrical conditions.

Results

Specific inclusion and exclusion criteria were employed during the study process. A total of 744 226 women have been identified with at least one delivery during the study period with 98 792 of them (13.3%) having at least one neurological diagnosis received during 2004–2016 before their first gestation in the time frame of the study. The vast majority of diagnosis codes were related to different types of headaches affecting 69 149 (9.3%) individuals. The most prevalent diagnoses following headaches were dizziness and giddiness (15 589 patients [2.1%]; nerve, nerve root and plexus disorders (10 375 patients [1.4%]); epileptic disorders (7028 patients [0.9%]); neurological diseases of vascular origin (6091 patients [0.8%]); other disorders of the nervous system (5358 patients [0.7%]); and demyelinating diseases of the central nervous system (2129 patients [0.3%]). The present findings of our study show high prevalence of pregestational neurological disorders, the dominance of headaches followed by the rather nonspecific diagnosis of dizziness and giddiness, the relevance of nerve, nerve root and plexus disorders and epilepsy, and the importance of cerebrovascular disorders among women of childbearing age.

Conclusion

The present research findings can help healthcare professionals, researchers and decision makers in adopting specific health policy measures based on nationwide data and further aid the development of new diagnostic and therapeutic algorithms of various neurological manifestations concerning women of childbearing age.

NOP01, a NOP receptor agonist, produced potent and peripherally restricted antinociception in a formalin-induced mouse orofacial pain model

Orofacial pain is one of the most common medical challenges. A preliminary report indicates that the NOP receptor may act as a therapeutic target in orofacial pain. Previous studies have shown that [(pF)Phe⁴, Aib⁷, Aib¹¹, Arg¹⁴, Lys¹⁵]N/OFQ-NH₂ (NOP01) functions as a potent NOP receptor peptide agonist. This work aims to investigate the antinociception of NOP01 and its possible action mechanisms in a formalin-induced mouse orofacial pain model at different levels. Our results demonstrated that local, intraperitoneal (i.p.) or intrathecal (i.t.) injection of NOP01 produced dose-related antinociception in both phases of the formalin pain, which could be inhibited by the NOP receptor antagonist but not the classical opioid receptor antagonist. Furthermore, the antinociception induced by systemic NOP01 was blocked by local but not spinal pretreatment with the NOP receptor antagonist, suggesting the involvement of the peripheral NOP receptor in NOP01-induced systemic antinociception. Moreover, local injection of NOP01 markedly suppressed the expression of c-Fos protein induced by formalin in ipsilateral trigeminal ganglion (TG) neurons. In conclusion, this work suggests that NOP01 exerts significant antinociception on orofacial pain at both peripheral and spinal levels via the NOP receptor. Notably, NOP01 cannot readily penetrate the blood-brain barrier. Thus, NOP01 may behave as a potential compound for developing peripherally restricted analgesics.

Management of chronic idiopathic pain in patients with dental implant without a clear pathological lesion: A retrospective study

Non-nociceptive, persistent idiopathic facial pain (PIFP) is a poorly localized, continuous dull pain that occurs even in the absence of apparent pathological lesions or clinical neurologic deficiency. This study aimed to investigate the disease characteristics of PIFP that developed after dental implant treatments. The clinical characteristics of pain as well as treatment method and outcomes were retrospectively analyzed in 20 patients diagnosed with PIFP. The patients developed pain either after implant fixation or prosthetic treatment. In most of the patients, the pain persisted not only around the implant region but also at a distant site from the related implant (13/20, 65%). Many patients desired removal of the implants to manage the pain although the pain was not considered to be related to the implant treatment itself. In 12 patients, the related implants were removed but 67% (n = 8/12) of the patients still experienced chronic pain after implant removal. Medication helped decrease the pain in most patients (n = 17). Pregabalin and clonazepam showed relatively higher efficiency than other medications for controlling the pain. The results showed that although the onset of PIFP was related to dental implant treatment, implant removal could not be considered a reliable option for the management of PIFP. Although medication controls the pain at least partially, complete pain control with medication should not be expected. These results demonstrate that an accurate diagnosis of PIFP is important for the selection of appropriate treatment.

Referred Orofacial Pain as an Initial Symptom of Distant, Nonmetastatic Cancer: Report of a Case and Review of the Literature

Referred orofacial pain as the first symptom of an otherwise silent distant, nonmetastatic cancer has been reported, but there is sparse literature on the subject. Referred pain may not be considered in the orofacial pain differential diagnosis because of its rarity; however, this may delay a cancer diagnosis. The authors present a case report and a review of the English literature. Peer-reviewed publications were identified through a systematic search of MEDLINE, Embase, and Cochrane CENTRAL. Historic cases were reviewed, and available data regarding demographics, pain characteristics, treatment, cancer diagnosis, and outcome were extracted. Thirty-seven cases were identified. All cancers were intrathoracic. The average age was 54.1 years with a slight female predominance (3:2). Common pain characteristics were (1) diffuse location affecting the ear (76%), jaw (46%), and temple (30%); (2) constant duration (65%); (3) aching quality (74%); (4) severe intensity (94%); and (5) associated systemic symptoms (68%) such as weight loss and digital clubbing. The average time from the onset of facial pain to seeking medical attention was 9 months, and the average time from seeking medication attention to cancer diagnosis was 8 months. Orofacial pain was often attributed to odontogenic (35%) or neuropathic (25%) causes, and treatments for these conditions were also common. The impact of referred orofacial pain on the cancer prognosis was not possible because of the nature of the reviewed studies (case reports with no comparison group). Cancer-associated referred orofacial pain as a first symptom is rare but should be considered in cases with intractable pain and associated systemic symptoms.

Neuropathic orofacial pain: Characterization of different patient groups using the ICOP first edition, in a tertiary level Orofacial Pain Clinic

OBJECTIVE

To characterize patients with chronic neuropathic orofacial pain in accordance with the International Classification of Orofacial Pain (ICOP first edition) criteria.

STUDY DESIGN

A retrospective chart review of 108 patients was conducted. The most common categories observed were trigeminal neuralgia (TN) (25.9%), burning mouth syndrome (BMS) (11.1%), persistent idiopathic facial pain (PIFP) (26.9%), and posttraumatic trigeminal neuropathic pain (PTTNP) (26.9%); 9.3% of patients could not be categorized.

RESULTS

TN and BMS was more prevalent in the sixth decade, and PIFP and PTTN were more prevalent in the fifth decade. All categories showed female predilection. The pain in TN was predominantly episodic, described as "sharp shooting" and like an "electric shock," unilateral and affecting the V2 division, and with trigger zones in 50% of patients. Pain in BMS was predominantly constant and described as "burning," with the tongue being the most common site. Pain in PIFP and PTTNP was as follows: varied from constant to episodic; described as "burning," "sharp shooting," "throbbing," or "dull aching"; intraoral or extraoral; and mostly involving the V2 or V3 division.

CONCLUSION

This study is the first to characterize patients with neuropathic orofacial pain using the new ICOP criteria. PIFP and PTTNP were most commonly misdiagnosed categories. Using diagnostic criteria will increase the understanding of this patient group.

Differences in the Clinical Characteristics of Persistent Idiopathic Facial Pain (Atypical Odontalgia) Patients with or Without Neurovascular Compression of the Trigeminal Nerve

Background

Persistent idiopathic facial pain (PIFP) is the unexplained pain along the territory of the trigeminal nerve, including nonorganic tooth pain called atypical odontalgia (AO). Though PIFP is debilitating to patients’ livelihood and well-being, its pathophysiology remains poorly understood. Although neurovascular compression (NVC) of the trigeminal nerve is known to be associated with trigeminal neuralgia (TN), the relationship between NVC and other orofacial pains has not been fully elucidated.

Methods

In this study, we investigated the differences in the characteristics of PIFP (primarily AO) patients in the presence or absence of NVC. A retrospective analysis was performed on data from 121 consecutive patients who had been diagnosed with unilateral PIFP according to the criteria of the International Classification of Headache Disorders (ICHD)–3 and underwent magnetic resonance imaging scans of the head.

Results

In the group without NVC, characteristic findings were significant for psychiatric morbidity, somatization, and pain disability, when compared with the group with NVC. Furthermore, the group without NVC exhibited significant headache, noncardiac chest pain, shortness of breath, and pain catastrophizing.

Conclusions

These results suggest that PIFP patients can be divided into two groups: one consistent with a neuropathic pain phenotype when NVC is present and a functional somatic symptom phenotype when presenting without NVC. Our findings may enable a more precise understanding of pathophysiology of PIFP and lead to better treatment strategies.

A novel gabapentin analogue assuages neuropathic pain response in chronic sciatic nerve constriction model in rats

Gabapentin (GBP) is an established drug that has been used in the management of symptoms of neuropathy but it is associated with unwanted side effects such as sedation and motor incoordination. The goal of the study was to find out a drug with greater efficacy and safety for the treatment of neuropathic pain. Our previously synthesized GABA analogue (Gabapentsal, GPS) was tested (25-100 mg/kg, i.p) in chronic constriction injury (CCI) induced nociceptive model of static allodynia, dynamic allodynia, thermal hyperalgesia, mechanical hyperalgesia and cold allodynia in rats (Sprague Dawley). Open field and rotarod tests were performed to assess the impact of GPS on the motor performance of the animals. GBP (100 mg/kg, i.p) was used as a standard for comparison. GPS dose dependently reduced static (P <0.001) and dynamic allodynia (P <0.001), thermal hyperalgesia (P <0.001), mechanical hyperalgesia (P < 0.001) and cold allodynia (P < 0.001). In comparison to GBP, GPS failed to alter any significantly the motor performance of rats in both the open field and rotarod assays. These results suggest that GPS is effective in alleviating nociception in CCI neuropathic pain model but free from the side effect of motor discoordination seen in the treatment with GBP. In conclusion, GPS may prove to be a prospectively more effective and safer option in the management of neuropathic syndromes.

Repetitive percutaneous radiofrequency thermocoagulation for persistent idiopathic facial pain and central neuropathic pain attributed to multiple sclerosis-a retrospective monocentric analysis

BACKGROUND

Persistent idiopathic facial pain (PIFP) is a debilitating chronic pain condition with pain radiating to trigeminal dermatomes. Typically, there are no pathological findings that can be identified during workup and therapy is symptomatic. Facial pain is common in patients with multiple sclerosis (central neuropathic pain attributed to MS). Our aim was to evaluate the effectiveness of percutaneous radiofrequency thermocoagulation (PRTC) of the gasserian ganglion and the duration of pain relief, as well as the identification of factors associated with its outcome.

METHODS

Data on all the above-mentioned patients that have been treated with PRTC between 2009 and 2019 were included into the study. The outcome was assessed with a six-tiered score from 1 (complete remission) to 6 (no benefit). Univariate and multivariate analyses were performed in order to obtain factors associated with the outcome.

RESULTS

A total of 52 patients were included. The total number of procedures performed was 114. 61.5% of patients who experienced temporary pain relief that lasted for a median of 60 days (range 3-1490 days). In patients with recurrence, the fraction of successful interventions was higher, and also transient, with successful pain amelioration in over 80% of patients. Successful responses to PRTC were observed in 27.9% after 1 year, 19.4% after 2 years, and 8.3% after 3 years. The only independent variable predicting pain relief was a repeat intervention with a history of ≥ 2 interventions (OR: 4.36, 95%-CI: 1.34-14.34, p = 0.015). No severe complications occurred.

CONCLUSIONS

Our data showed good and immediate pain relief after PRTC in the majority of our patients. PRTC is a low-risk procedure that can be discussed as an option in case of failure of medical treatment even in critically ill patients and can be repeated with good results when necessary. Long-term pain amelioration, even with repeated procedures, was not possible and no patient was permanently cured.

Neuromodulators for Atypical Facial Pain and Neuralgias: A Systematic Review and Meta-Analysis

OBJECTIVE

To evaluate the effectiveness of neuromodulating agents for the management of atypical facial pain and primary facial neuralgias.

METHODS

We searched MEDLINE, Embase, CINAHL, and ClinicalTrials.gov databases for original research articles that examine the effectiveness and adverse reactions of pharmacologic therapy for the treatment of trigeminal neuralgia and atypical facial pain. Studies that included surgical interventions for atypical facial pain or facial pain secondary to other causes were excluded. Meta-analysis was conducted for reductions in symptom scores and adverse effects.

RESULTS

Of 3,409 articles screened, 73 full-text articles were included, consisting of 45 observational studies and 29 randomized controlled trials. Twenty-four different pharmacological agents were assessed; carbamazepine was the most frequently studied while botulinum toxin A demonstrated the highest consistency in reduction of symptom scores. Pooled estimate of three randomized controlled trials revealed that patients with trigeminal neuralgia who received botulinum toxin A had higher odds (odds ratio 7.46; 95% CI 3.53-15.78) of achieving a ≥50% reduction in visual analogue scale scores compared to controls. Pooled estimate of 15 observational studies showed that three-fourths of patients with trigeminal neuralgia who received carbamazepine experienced clinically significant pain reduction (prevalence proportion 0.75; 95% CI 0.66-0.83).

CONCLUSIONS

Patients receiving botulinum toxin A for trigeminal neuralgia had higher odds of achieving ≥50% reduction in pain scores. A significant proportion of patients with trigeminal neuralgia experienced positive response to carbamazepine. There was moderate evidence for amitriptyline in patients with atypical facial pain. Standardization of outcome reporting would facilitate future quantitative comparisons of therapeutic effectiveness. Laryngoscope, 131:1235-1253, 2021.

Chronic Facial Pain: Trigeminal Neuralgia, Persistent Idiopathic Facial Pain, and Myofascial Pain Syndrome-An Evidence-Based Narrative Review and Etiological Hypothesis

Trigeminal neuralgia (TN), the most common form of severe facial pain, may be confused with an ill-defined persistent idiopathic facial pain (PIFP). Facial pain is reviewed and a detailed discussion of TN and PIFP is presented. A possible cause for PIFP is proposed. (1) Methods: Databases were searched for articles related to facial pain, TN, and PIFP. Relevant articles were selected, and all systematic reviews and meta-analyses were included. (2) Discussion: The lifetime prevalence for TN is approximately 0.3% and for PIFP approximately 0.03%. TN is 15-20 times more common in persons with multiple sclerosis. Most cases of TN are caused by neurovascular compression, but a significant number are secondary to inflammation, tumor or trauma. The cause of PIFP remains unknown. Well-established TN treatment protocols include pharmacotherapy, neurotoxin denervation, peripheral nerve ablation, focused radiation, and microvascular decompression, with high rates of relief and varying degrees of adverse outcomes. No such protocols exist for PIFP. (3) Conclusion: PIFP may be confused with TN, but treatment possibilities differ greatly. Head and neck muscle myofascial pain syndrome is suggested as a possible cause of PIFP, a consideration that could open new approaches to treatment.

Factors Associated With Long-Term Risk of Recurrence After Percutaneous Radiofrequency Thermocoagulation of the Gasserian Ganglion for Patients With Trigeminal Neuralgia Involving the Ophthalmic Division: A Retrospective Study

OBJECTIVE

To evaluate risk factors associated with recurrence after radiofrequency thermocoagulation (RFT) of the gasserian ganglion among patients with ophthalmic trigeminal neuralgia (TN) and prognostic factors in terms of recurrence-free survival (RFS) during a long-term follow-up.

METHODS

From January 2005 to December 2017, 300 patients with ophthalmic TN underwent RFT. A retrospective analysis of 14-year outcomes was performed. Kaplan-Meier analysis was used for RFS after the procedure. Univariate and multivariate Cox regression analyses were performed to identify risk factors for pain recurrence.

RESULTS

The initial effective rate of RFT for ophthalmic TN was 92%. The mean follow-up time was 77.38 ± 43.24 months. The cumulative probability of RFS was 86.94% at 1 year, 80.03% at 2 years, 77.27% at 3 years, 74.01% at 5 years, and 59.92% at 10 years after RFT. The mean duration of RFS was 114.67 months (95% confidence interval [CI] 106.27 to 123.06 months). In multivariate analysis, atypical pain (hazard ratio [HR] = 2.831, 95% CI 1.759 to 4.554, P < 0.001) and mild facial hypesthesia (HR = 2.540, 95% CI 1.309 to 4.931, P = 0.006) before RFT were independently associated with pain recurrence. Patients with a prognostic index (PI) > 1.27 were at high risk for pain recurrence. Major complications included troublesome dysesthesia (0.7%), keratitis (10.9%), diplopia (0.4%), facial paresthesia (6.2%), and masseter weakness (12.7%). Masseter weakness was more common in patients with V3 branch involvement. Three patients lost their sight due to keratitis.

CONCLUSION

Our study investigated long-term outcomes and complications of RFT for ophthalmic TN. Patients at high risk for pain recurrence were identified, which might provide a basis for clinical decision making before RFT.

Retrospective Study on Ganglionic and Nerve Block Series as Therapeutic Option for Chronic Pain Patients with Refractory Neuropathic Pain

Objective

Current recommendations controversially discuss local infiltration techniques as specific treatment for refractory pain syndromes. Evidence of effectiveness remains inconclusive and local infiltration series are discussed as a therapeutic option in patients not responding to standard therapy. The aim of this study was to investigate the effectiveness of infiltration series with techniques such as sphenopalatine ganglion (SPG) block and ganglionic local opioid analgesia (GLOA) for the treatment of neuropathic pain in the head and neck area in a selected patient group.

Methods

In a retrospective clinical study, 4960 cases presenting to our university hospital outpatient pain clinic between 2009 and 2016 were screened. Altogether, 83 patients with neuropathic pain syndromes receiving local infiltration series were included. Numeric rating scale (NRS) scores before, during, and after infiltration series, comorbidity, and psychological assessment were evaluated.

Results

Maximum NRS before infiltration series was median 9 (IQR 8–10). During infiltration series, maximum NRS was reduced by mean 3.2 points (SD 3.3, p < 0.001) equaling a pain reduction of 41.0% (SD 40.4%). With infiltration series, mean pain reduction of at least 30% or 50% NRS was achieved in 54.2% or 44.6% of cases, respectively. In six percent of patients, increased pain intensity was noted. Initial improvement after the first infiltration was strongly associated with overall improvement throughout the series.

Conclusion

This study suggests a beneficial effect of local infiltration series as a treatment option for refractory neuropathic pain syndromes in the context of a multimodal approach. This effect is both significant and clinically relevant and therefore highlights the need for further randomized controlled trials.

Nonopioid Adjuncts and Alternatives

Multimodality nonopioid analgesia can be effective for pain control. Balancing risks and benefits of treatment should guide the appropriateness of opioid versus nonopioid pain control.

A Case of Post-traumatic Persistent Nasal Pain

Nasal pain is a complex and misdiagnosed entity with various peripheral and central etiologies. It is often a bothersome, treatment-resistant condition and could be spontaneous or post-traumatic. Although pain usually occurs immediately after injury, rarely it may occur long after the nasal trauma. Due to its rarity, successful treatment is difficult because of the lack of standardized options. According to our experience, an effective therapeutic approach should take into account both local inflammatory factors and aberrant nerve modulations. We describe the case of a young woman complaining of a delayed onset persistent nasal pain occurring 1 month after facial trauma and who has improved with the addition of intranasal steroids to first-line neuropathic pain treatment.

Atypical Facial Pain

Atypical facial pain (AFP), or persistent idiopathic facial pain, is a chronic and diffuse distribution of facial pain along the territory of the trigeminal nerve. This condition occurs in the absence of any neurologic deficit or any other obvious etiology. AFP is one of the most challenging conditions to diagnose due to lack of clear diagnostic criteria. Diagnosis of this condition is made by exclusion of other known etiologies. Specific disease modalities cannot be targeted, resulting in a deficiency of clear treatment protocol. Despite the limitations of evidence-based literature, tricyclic antidepressants have proved effective and are considered the treatment choice for AFP.

Opioid and Endocannabinoid System in Orofacial Pain

Orofacial pain disorders are frequent in the general population and their pharmacological treatment is difficult and controversial. Therefore, the search for novel, safe and efficient analgesics is an important but still elusive goal for contemporary medicine. In the recent years, the antinociceptive potential of endocannabinoids and opioids has been emphasized. However, concerns for the safety of their use limit their clinical applications. the possibility of modulating the activity of endocannabinoids by regulation of their synthesis and/or degradation offers an innovative approach to the treatment of pain. A rat model of trigeminal pain, utilizing tongue jerks evoked by electrical tooth pulp stimulation during perfusion of the cerebral ventricles with various neurotransmitter solutions can be used in the pharmacological studies of nociception in the orofacial area. The aim of this review is to present the effects of pharmacological activity of opioids and endocannabinoids affecting the transmission of the sensory information from the orofacial area on the example of trigemino-hypoglossal reflex in rats.

Persistent Idiopathic Facial Pain Originating from Cervical Abnormalities

BACKGROUND

Persistent idiopathic facial pain is characterized by persistent facial or oral pain in the absence of a neurologic deficit. This underexplored pain may be conducted by various nerves, including cranial nerves and upper cervical spinal roots, and its etiology is unclear.

CASE DESCRIPTION

A patient presented with persistent idiopathic facial pain associated with occipital muscle stiffness after an improper neck massage. The patient achieved almost complete pain relief by coblation of right upper cervical nerves (C1 and C2 spinal roots) followed by continuous cervical epidural analgesia for a period of 3 weeks. The analgesic effect was stable during the 3-month follow-up period.

CONCLUSIONS

Persistent idiopathic facial pain may be cervicogenic, and treatments focusing on cervical spinal roots may provide satisfactory pain control in patients with cervical abnormalities.

Neuropathic Characteristics In Patients With Persistent Idiopathic Facial Pain

Background

Persistent idiopathic facial pain (PIFP) is a subtype of painful cranial neuropathies and other facial pains. The involvement of neuropathic mechanisms in PIFP, however, remains controversial. Using the Douleur Neuropathique 4 (DN4) questionnaire, the present study examined neuropathic characteristics in patients with PIFP.

Methods

The multi-institutional retrospective study collected the following clinical data from 205 consecutive patients with adult chronic pain: gender, age, BMI, diseases causing chronic pain, disease duration, visual analogue scale score of pain strength, and DN4 score. To compare neuropathic characteristics between PIFP and postherpetic neuralgia (PHN), we selected patients with PIFP (n=19) and patients with PHN (n=33), and performing a case-control study in which each patient with PHN or PIFP was matched by age and gender (n=16 in each group).

Results

DN4 score was significantly lower in the PIFP group than in the PHN group before and after matching. The incidence when DN4 was ≥4 was 10.5% before matching and 12.5% after matching in the PIFP group, both of which were significantly lower than those in the PHN group before and after matching (66.7% and 75.0%).

Conclusion

Ten percent of the PIFP patients likely show neuropathic pain characteristics.

Efficacy of virtual reality to reduce chronic low back pain: Proof-of-concept of a non-pharmacological approach on pain, quality of life, neuropsychological and functional outcome

Objectives

Chronic pain, such as low-back pain, can be a highly disabling condition degrading people’s quality of life (QoL). Not every patient responds to pharmacological therapies, thus alternative treatments have to be developed. The chronicity of pain can lead to a somatic dysperception, meaning a mismatch between patients’ own body perception and its actual physical state. Since clinical evaluation of pain relies on patients’ subjective reports, a body image disruption can be associated with an incorrect pain rating inducing incorrect treatment and a possible risk of drug abuse. Our aim was to reduce chronic low-back pain through a multimodal neurorehabilitative strategy using innovative technologies to help patients regain a correct body image.

Methods

Twenty patients with chronic low-back pain were included. Before and after treatment, patients underwent: a neurological exam; a neuro-psychological evaluation testing cognitive functions (memory, attention, executive functions) and personality traits, QoL and mood; pain ratings; sensorimotor functional abilities’ testing. Patients underwent a 6 week-neurorehabilitative treatment (total 12 sessions) using virtual reality (VRRS system, Khymeia, Italy). Treatment consisted on teaching patients to execute correct movements with the painful body parts to regain a correct body image, based on the augmented multisensory feedback (auditory, visual) provided by the VRRS.

Results

Our data showed significant reductions in all pain rating scale scores (p<0.05); significant improvements of QoL in the domains of physical functioning, physical role functioning, bodily pain, vitality, and social role functioning; improvements in cognitive functions (p<0.05); improvements in functional scales (p<0.05) and mood (p = 0.04).

Conclusion

This non-pharmacological approach was able to act on the multi-dimensional aspects of pain and improved patients’ QoL, pain intensity, mood and patient’s functional abilities.

Diagnostic delay and suboptimal management in persistent idiopathic facial pain and persistent dentoalveolar pain; a cross-sectional study

OBJECTIVES

The aim of this study was to explore the diagnostic and therapeutic challenges encountered by patients with persistent idiopathic facial pain (PIFP) and to investigate factors influencing its delayed diagnosis.

STUDY DESIGN

In this cross-sectional study, 34 patients with newly diagnosed PIFP were interviewed. Data about diagnostic delay, number and nature of previous consultations, and previous medical and surgical interventions were recorded. Pearson's correlation and Student t test were used to examine the differences among the variables in relation to diagnostic delay.

RESULTS

The average time between the onset of symptoms to correct diagnosis was 19.3 ± 11.1 months. Diagnostic delay was significantly longer in patient with pain localized to intraoral sites (22.6 ± 7.4) compared with patients with extraoral pain (16.1 ± 9.3). The average number of health care professionals consulted before correct diagnosis was 3.7 ± 2.3. General dental practitioners were the most commonly consulted health care professionals (n = 27; 79.4%). On average, patients were given 2.3 ± 0.24 misdiagnoses before the correct diagnosis was determined and were prescribed 3.5 ± 2.4 classes of drugs. Twenty-five patients (73.5%) underwent unnecessary surgical/dental interventions.

CONCLUSIONS

Patients with PIFP are frequently misdiagnosed, leading to prescription of ineffective medications and unnecessary investigations and surgical interventions. Educational efforts should emphasize on improving knowledge and awareness of this condition.

Near-resolution of persistent idiopathic facial pain with low-dose lumbar intrathecal ziconotide: a case report

Purpose

Persistent idiopathic facial pain (PIFP) is a poorly defined and debilitating chronic pain state with a challenging and often inadequate treatment course. This is the first case report identifying the novel use of low-dose lumbar intrathecal ziconotide to successfully treat PIFP with nearly complete resolution of pain and minimal to no side effects.

Methods

The patient was a 37 year-old female whose PIFP was refractory to multimodal medication management and multiple neurovascular surgical interventions. A single-shot lumbar intrathecal trial of ziconotide (2.5 mL, equivalent 2.5 μg) was injected when she was at her baseline pain level — VAS 7/10. She received complete resolution of her pain for about 9 hours, concordant with ziconotide’s half-life. She was subsequently implanted with a lumbar intrathecal delivery system.

Results

The patient experienced complete resolution of her facial pain with a single-shot intrathecal trial of ziconotide. The intrathecal pump system has provided nearly complete (VAS 1/10) pain relief. Two flares of pain occurred 10 and 18 months after pump placement, which subsequently resolved after increasing the ziconotide dose by 0.5 μg/day on each occasion. The patient is currently maintained on a dose of 2.0 μg/day and is pain-free.

Conclusion

This is the first case report describing the use of a single-shot lumbar intrathecal trial of ziconotide and subsequent placement of lumbar (as opposed to thoracic) intrathecal ziconotide pump for PIFP. A single-injection intrathecal trial is a low-risk, viable option for patients with this debilitating and frustrating pain condition. Successful trials and subsequent intrathecal pump placement with ziconotide may supplant multimodal medication management and/or invasive orofacial surgical intervention for PIFP.

The role of electrophysiological investigations of masticatory muscles in patients with persistent idiopathic facial pain

INTRODUCTION

The authors tried to establish whether there is any electrophysiological difference of masticatory muscle activity between patients with persistent idiopathic facial pain (PIFP) and healthy subjects.

METHODS

Twenty-eight PIFP patients (6 men and 22 women, mean age 40 years) and 28 normal subjects (12 men and 16 women, mean age 40 years) underwent EMG of temporal and masseter muscles before and after transcutaneous electric nerve stimulation (TENS).

RESULTS

After TENS stimulation, the mean amplitude difference was found to be smaller than the baseline before TENS in the PIFP patients compared with healthy subjects.

CONCLUSIONS

The peculiar behavior of masticatory muscles after TENS could be relevant in order to explain the well-known improvement of pain reported by some PIFP patients after orthosis positioning.

Nonmigraine Headache and Facial Pain

The vast majority of headache patients encountered in the outpatient general medicine setting will be diagnosed with a primary headache disorder, mostly migraine or tension-type headache. Other less common primary headaches and secondary headaches, related to or caused by another condition, are the topic of this article. Nonmigraine primary headaches include trigeminal autonomic cephalalgias, primarily cluster headache; facial pain, primarily trigeminal neuralgia; and miscellaneous headache syndromes, such as hemicrania continua and new daily persistent headache. Selected secondary headaches related to vascular disease, cerebrospinal fluid dynamics, and inflammatory conditions are also reviewed.

Microcurrent technology for rapid relief of sinus pain: a randomized, placebo-controlled, double-blinded clinical trial

Background

Transcutaneous electrical nerve stimulation has proven to be effective in alleviating chronic pain from facial myalgias. We evaluated the efficacy of a novel handheld microcurrent‐emitting device in short‐term, office‐based treatment of patients with sinus pain. This device, which is U.S. Food and Drug Administration (FDA)‐cleared, detects and treats regions corresponding to nerve fibers.

Methods

Randomized, double‐blinded, placebo‐controlled trial. Seventy‐one participants with facial pain attributed to self‐reported nasal/sinus disease were recruited from a tertiary rhinologic practice and the surrounding community and randomly assigned to either office‐based use of an active (n = 38) or placebo (n = 33) microcurrent emitter. The study device was repetitively applied by each patient to the bilateral periorbital areas for 5 minutes. A visual analogue scale (VAS) for pain severity was administered before, and 10 minutes after, treatment.

Results

Active microcurrent‐treated patients had a reduction in mean pain score from 5.63 pretreatment to 3.97 posttreatment (mean difference, 1.66; 95% confidence interval [CI], 1.20 to 2.12). Patients using the sham device also reported sinus pain reductions (mean difference, 0.91; 95% CI, 0.61 to 1.21). However, the active device demonstrated a significantly greater reduction in pain compared to sham (0.75‐point difference, p = 0.007). Notably, 23.7% of patients using the active device had a reduction of 3 or more points by VAS compared to 0% of sham device patients (p = 0.003). One minor occurrence of transient facial skin erythema was noted.

Conclusion

This trial suggests that treatment of rhinologic facial pain using this noninvasive microcurrent device is safe and effective in providing rapid relief of nasal/sinus pain. Additional studies with longer term follow‐up are warranted.

Bulbar Muscle Weakness in the Setting of Therapeutic Botulinum Injections

We present a case of new-onset bulbar muscle weakness in the setting of therapeutic botulinum injections for spasticity in a teenaged patient with cerebral palsy. Through a careful history, a systemic effect of the local injections was suspected, and the patient’s symptoms improved with a decrease in the dosing of the botulinum injections.

Treatment of Facial Pain with I Ching Balance Acupuncture

Background: Trigeminal neuralgia (TN) is the most common cranial neuralgia in adults, with a slightly higher incidence in women than in men. This chronic pain condition affects the trigeminal nerve, also known as the 5th cranial nerve. It is one of the most deeply distributed nerves in the head. Antiseizure drugs are the main biomedical treatment of TN. However, TN is not the only source of facial pain. Background persistent idiopathic facial pain (PIFP) is also a chronic disorder, recurring daily for more than 2 hours per day over more than 3 months. PIFP occurs in the absence of a neurologic deficit. The underlying pathophysiologies of TN and PIFP are still unknown, and treatment options have not been sufficiently evaluated. Nevertheless, neuropathic mechanisms could be relevant in both TN and PIFP. Cases: A 65-year-old Caucasian female with left facial pain was diagnosed by a neurologist with TN ∼2.5 years prior to seeking acupuncture treatment. A 42-year-old Caucasian female with left and right facial pain was diagnosed by a neurologist with PIFP ∼3 years prior to commencing acupuncture treatment. The cause of facial pain was treated with 60-minute sessions of I Ching Balance Acupuncture (ICBA) twice per week. Prior to each session, the effect of the previous session was recorded carefully in the patients' files. Results: A complete dissipation of pain was achieved after 29 and 60 ICBA sessions in the TN and the PIFP patient, respectively. Conclusions: The present article is the one of the first to demonstrate the efficacy of ICBA treatment for refractory facial pain. As the present article shows, ICBA treatment affects facial pain of different types successfully. However, additional larger-scale studies are necessary to validate the efficacy of ICBA in TN and PIFP treatment.

Orofacial pain - an update on diagnosis and management

The diagnosis and management of orofacial pain may be challenging due to complex histories, pathophysiology and associated psychosocial co-morbidities such as depression and anxiety. Neuropathic facial pain conditions such as burning mouth syndrome (BMS), persistent idiopathic facial pain (PIFP), atypical odontalgia (AO) and trigeminal neuralgia (TN) require early recognition by primary care clinicians and referral to secondary care. Acute pain-related temporomandibular disorder (TMD) may be managed in the primary care setting, with identification of those at risk of developing chronic TMD receiving an early referral to secondary care. Adopting a biopsychosocial approach, consisting of physical therapies, pharmacotherapy and psychological support can lead to effective management and may limit the negative impact of facial pain upon quality of life and daily functioning.

A novel miniature, wireless neurostimulator in the management of chronic craniofacial pain: Preliminary results from a prospective pilot study

OBJECTIVE

To report a novel wireless neuromodulation system for treatment of refractory craniofacial pain.

BACKGROUND

Previous studies utilizing peripheral nerve stimulation (PNS) of the occipital and trigeminal nerves reported positive outcomes for alleviating neuropathic pain localized to the craniofacial and occipital areas. However several technological limitations and cosmetic concerns inhibited a more widespread acceptance and use of neuromodulation. Also, a relatively high incidence of adverse events like electrode erosions, dislocation, wire fracture and/or infection at the surgical site mandates a change in our approach to neuromodulation technology and implant techniques in the craniofacial region.

METHODS

We report a novel approach for the management of craniofacial pain with a wirelessly powered, minimally invasive PNS system. The system is percutaneously implanted and placed subcutaneously adjacent to affected facial nerves via visual guidance by the clinician. In this feasibility study, pilot evidence was gathered in a cohort of ten subjects suffering from a combination of chronic headaches, facial pain for at least 15 days per month and for at least 4h/day.

RESULTS

At four weeks post-implant follow up, all patients reported sustained pain relief of the primary pain area. Electrode location and total number of electrodes used per subject varied across the cohort. The average pain reduction using the visual analog scale was ≥82%. The procedure had no adverse events or side effects.

CONCLUSION

Percutaneous placement of a wireless neurostimulation device directly adjacent to affected craniofacial nerve(s) is a minimally invasive and reversible method of pain control in patients with craniofacial pain refractory to conventional medical managements. Preliminary results are encouraging and further larger scale studies are required for improved applications.

How and when to refer patients diagnosed with secondary headache and other craniofacial pain in the Emergency Department and Primary Care: Recommendations of the Spanish Society of Neurology's Headache Study Group

INTRODUCTION

When secondary headache is suspected and the patient is referred to the emergency department or to the outpatient neurology clinic, it is important to know which are the appropriate complementary examinations to perform and the suitable referral pathway for patients to follow. In order to establish recommendations on this matter, the Spanish Society of Neurology's Headache Study Group (GECSEN) has decided to issue a series of agreed recommendations constituting a referral protocol for patients with headache and/or craniofacial neuralgias.

DEVELOPMENT

Young neurologists with an interest and experience in headache were invited to draft a series of practical guidelines in collaboration with GECSEN's Executive Committee. For practical reasons, the document was divided into 2 articles: the first focuses on primary headaches and craniofacial neuralgias and this second article on secondary headaches and other craniofacial pain. In order for the recommendations to be helpful for daily practice, they follow a practical approach, with tables summarising referral criteria, examinations to be performed, and referral to other specialists.

CONCLUSIONS

We hope to offer a guide and tools to improve decision-making regarding patients with headache, identifying complementary tests to prioritise and referral pathways to be followed, in order to avoid duplicated consultations and delayed diagnosis and treatment.

Effects of centrally administered endocannabinoids and opioids on orofacial pain perception in rats

BACKGROUND AND PURPOSE

Endocannabinoids and opioids play a vital role in mediating pain-induced analgesia. The specific effects of these compounds within the orofacial region are largely unknown. In this study, we tried to determine whether an increase in cannabinoid and opioid concentration in the CSF affects impulse transmission between the motor centres localized in the vicinity of the third and fourth cerebral ventricles.

EXPERIMENTAL APPROACH

The study objectives were realized on rats using a method that allows the recording of the amplitude of evoked tongue jerks (ETJ) in response to noxious tooth pulp stimulation. The amplitude of ETJ was a measure of the effect of neurotransmitters on neural structures.

KEY RESULTS

Perfusion of cerebral ventricles with anandamide (AEA), endomorphin-2 (EM-2), URB597, an inhibitor of fatty acid amide hydrolase (FAAH) and JZL195, a dual inhibitor of FAAH and monoacylglycerol lipase (MAGL) reduced the ETJ amplitude. The antinociceptive effect of AEA, EM-2, URB597 and JZL195 was blocked by CB₁ receptor antagonist, AM251 and by μ receptor-antagonist, β-funaltrexamine. In contrast to AEA, 2-arachidonoylglycerol alone did not decrease ETJ amplitude.

CONCLUSIONS AND IMPLICATIONS

We demonstrated that in the orofacial area, analgesic activity is modulated by AEA and that EM-2-induced antinociception was mediated by μ and CB₁ receptors. The action of AEA and EM-2 is tightly regulated by FAAH and FAAH/MAGL, by preventing the breakdown of endogenous cannabinoids in regions where they are produced on demand. Therefore, the current findings support the therapeutic potential of FAAH and FAAH/MAGL inhibitors as novel pharmacotherapeutic agents for orofacial pain.