Based on Virtual Screening and Simulation Exploring the Mechanism of Plant-Derived Compounds with PINK1 to Postherpetic Neuralgia

Accumulating evidence strongly supports that PINK1 mutation can mediate mitochondrial autophagy dysfunction in dopaminergic neurons. This study was conducted to determine the role of PINK1 in the pathogenesis of postherpetic neuralgia (PHN) and find new targets for its treatment. A rigorous literature review was conducted to identify 2801 compounds from more than 200 plants in Asia. Virtual screening was used to shortlist the compounds into 20 groups based on their binding energies. MM/PBSA was used to further screen the compound dataset, and vitexin, luteoloside, and 2'-deoxyadenosine-5'-monophosphate were found to have a score of - 59.439, - 52.421, and - 47.544 kcal/mol, respectively. Pain behavioral quantification, enzyme-linked immunosorbent assay, quantitative polymerase chain reaction, western blotting, and transmission electron microscopy were used to confirm the effective mechanism. Vitexin had the most significant therapeutic effect on rats with PHN followed by luteoloside; 2'-deoxyadenosine-5'-monophosphate had no significant effect. Our findings suggested that vitexin could alleviate PHN by regulating mitochondrial autophagy through PINK1.

Modelling the Public Health Burden of Herpes Zoster and the Impact of Adjuvanted Recombinant Zoster Vaccine in Five Selected Countries in Southeast Asia

INTRODUCTION

Herpes zoster (HZ) can cause substantial patient morbidity and lead to large healthcare costs. However, the disease burden of HZ in Southeast Asia may be underestimated. This study aimed to estimate the public health burden of HZ and the impact of vaccinating adults aged ≥ 50 years old in five Southeast Asian countries (Indonesia, Malaysia, Philippines, Thailand, and Vietnam), with adjuvanted recombinant zoster vaccine (RZV) compared with no vaccination.

METHODS

For each country, we adapted a static multicohort Markov model developed with a 1-year cycle length and lifetime horizon. Demographics were obtained from the World Health Organization, HZ incidence from a worldwide meta-regression reporting Asian-specific values, proportions of postherpetic neuralgia (PHN) and non-PHN complications from local/regional studies, and vaccine efficacy from a long-term follow-up trial. First-dose coverage and second-dose compliance were assumed to be 30% and 70%, respectively. A one-way deterministic sensitivity analysis (OWSA) and probabilistic sensitivity analysis (PSA) were performed to assess the robustness and uncertainty of inputs for each country.

RESULTS

Without RZV, it was estimated that there would be a total of approximately 10 million HZ cases, 2.1 million PHN cases, and 1.4 million non-PHN complications in individuals aged ≥ 50 years included in the model. Introducing RZV under 30% coverage could avoid approximately 2.2 million (22%) HZ cases, almost 500,000 (21%) PHN cases, and around 300,000 (22%) non-PHN complications. OWSA showed that first-dose coverage and initial HZ incidence had the largest impact on the estimated number of HZ cases avoided. The number needed to vaccinate ranged from 15 to 21 to prevent one case of HZ and from 68 to 104 to prevent one case of PHN across each country.

CONCLUSIONS

This study demonstrated that there is substantial HZ disease burden in older adults for the five selected countries in Southeast Asia, negatively impacting national healthcare systems. Introducing RZV could potentially reduce this burden. A graphical abstract is available with this article.

Efficacy of Paravertebral Injection of Interferon-α2b Combined with High-Voltage, Long-Term Pulsed Radiofrequency in DRG in Mitigation of Postherpetic Neuralgia: A Retrospective Study

OBJECTIVE

This investigation aims to evaluate the effectiveness of the paravertebral injection of recombinant human interferon-α2b in conjunction with high-voltage, long-term, pulsed radiofrequency (PRF) in the dorsal root ganglion for the mitigation of postherpetic neuralgia (PHN).

METHODS

This retrospective study included 84 individuals with acute PHN. The participants were divided into 3 groups. Group H was treated with interferon-α2b combined with high-voltage long-term PRF. Group C was treated with a combination of high-voltage, long-term PRF and a paravertebral injection (without recombinant human interferon-α2b), and group I was treated with interferon-α2b only. All the patients in the 3 groups were orally administered a 5-mg morphine hydrochloride quick-release tablet when a burst of pain occurred during treatment. The numerical rating scale for pain score, the interleukin-6 and galectin-3 levels, and the incidence of PHN were documented before and after therapy.

RESULTS

The pain intensity of all individuals decreased after therapy. Compared with group C, the numerical rating scale scores for group H were significantly reduced at 4, 8, and 12 weeks following therapy, and the PHN incidence was significantly lower. Compared with prior treatment, the recommended dosage of gabapentin capsules and immediate-release morphine hydrochloride tablets was reduced for group H. Compared with group C, the requirement for orally administrated gabapentin capsules and morphine hydrochloride tablets in group H was reduced significantly after treatment. No serious adverse reactions occurred in any of the 3 groups.

CONCLUSIONS

Within the context of treatment of acute PHN, the injection of interferon-α2b in conjunction with high-voltage, long-term application of PRF is more effective than PRF or the injection of interferon-α2b alone.

Progress in Radiofrequency Therapy for Zoster-Associated Pain About Parameters, Modes, Targets, and Combined Therapy: A Narrative Review

Zoster-associated pain (ZAP) is a painful condition that significantly impacts a patient's quality of life, often leading to postherpetic neuralgia (PHN). Over 30% of patients with herpes probably experience PHN. However, the understanding and treatment of ZAP remain inadequate. Common interventional treatments include radiofrequency therapy, nerve blocks, epidural block, and spinal cord electrical stimulation. Among these, radiofrequency therapy is widely used for pain control in ZAP, but the standard pulsed radiofrequency technique can still be improved. Researchers have explored different radiofrequency parameters, modes, targets, and combined treatments to enhance the therapeutic effect. In this paper, we review the latest research findings and incorporate our own departmental investigations. We conclude that high-voltage, long-duration pulsed radiofrequency and radiofrequency thermocoagulation therapy have shown improved therapeutic outcomes, despite some remaining limitations. Emphasis is placed on safety in intercostal nerve and extracranial nerve radiofrequency treatments. Combination therapy is also safe and effective; however, many studies have a low grade of evidence. Further high-quality research and systematic reviews are needed.

Effect of CT-Guided Repeated Pulsed Radiofrequency on Controlling Acute/Subacute Zoster-Associated Pain: A Retrospective Cohort Study

INTRODUCTION

Zoster-associated pain (ZAP) treatment and management is still inadequate. Repeated intervention protocol is often applied to manage ZAP. This study aimed to retrospectively investigate the effect of repeated applications of pulsed radiofrequency therapy on controlling acute/subacute ZAP.

METHODS

From March 2019 to December 2021, 150 patients with acute/subacute ZAP who underwent repeated application of pulsed radiofrequency treatment (R-PRF) and pulsed radiofrequency combined paravertebral block interventions (PRF + PVB) in the Pain Department of the affiliated Hospital of Jiaxing University were enrolled. Patients were grouped by intervention protocol and received at least 12 months of follow-up assessments using the Numerical Rating Scale score (NRSs), Pittsburg Sleep Quality Index (PSQI), Simple McGill Pain Questionnaire-2 score (SF-MPQ-2s), and follow-up interventions.

RESULTS

Both groups experienced a reduction in the incidence of clinically meaningful ZAP after the intervention therapy. In the R-PRF group, there were 36 cases of clinically meaningful ZAP within the first month post-treatment, while the PRF + PVB group had 38 cases. The incidence of clinically meaningful ZAP, as determined by multivariable generalized estimating equations, was 42.86% in the R-PRF group and 57.58% in the PRF + PVB group during the first month of follow-up. There was a significant difference in the incidence of clinically meaningful ZAP between the two groups after 1 month of treatment (adjusted odds ratio: 0.40; 95% confidence interval: 0.18-0.91; p = 0.03).

CONCLUSIONS

Both R-PRF and PRF + PVB treatments effectively relieve pain in patients with acute/subacute ZAP. However, R-PRF may have superior efficacy compared to PRF + PVB in reducing the incidence of clinically meaningful ZAP 1 month after treatment.

Gut Microbiota Modulation and Its Implications on Neuropathic Pain: A Comprehensive Literature Review

Neuropathic pain (NP) is a chronic pain disorder arising from somatosensory nervous system impairment. Extensive evidence supports the notion that the gut microbiota (GM) is crucial in maintaining human health by performing vital tasks. At the same time, its disruption has been linked to the emergence and advancement of an expanding range of disorders, including NP, in which GM could play a role in its pathophysiology. The crosstalk between the nervous system and GM happens through immune mediators, metabolites, and nervous structures and involves both central and peripheral nervous systems. This literature review aims to thoroughly investigate the function of modulating GM in the treatment of NP. It will achieve this by integrating existing knowledge, identifying underlying mechanisms, and evaluating the possible clinical consequences of exploiting the gut-brain axis. We will cover the main therapeutic applications of the described GM-modulators, such as probiotics, faecal microbiota transplantation, dietary supplements and emotional support, to the main kinds of NP in which any evidence, even if only pre-clinical, has been unravelled in recent years. The explored NP areas include chemotherapy-induced peripheral neuropathy, diabetic neuropathy, trauma-induced neuropathic pain, trigeminal neuralgia, postherpetic neuralgia and low back pain.

A retrospective cohort study evaluating the incidence of herpes zoster and postherpetic neuralgia after a live attenuated Oka-strain herpes zoster vaccine in a real-world setting in Japan

BACKGROUND

In Japan, freeze-dried live attenuated Oka-strain varicella-zoster virus vaccine, VVL (BIKEN), is available for adults aged ≥50 years to prevent herpes zoster (HZ). Although an increase in the antibody titer and cellular immune response has been demonstrated following vaccination with VVL (BIKEN), to date, no clinical studies have shown that the vaccine decreases the incidence of HZ and postherpetic neuralgia (PHN). This study investigated the incidence of HZ and PHN among adults aged ≥50 years who received a single dose of VVL (BIKEN) to prevent HZ.

METHODS

This retrospective cohort study investigated the incidence of HZ and PHN among adults aged ≥50 years who received a single dose of VVL (BIKEN) at a large hospital and affiliated clinics in Japan. A dispensing database and electronic medical records were used to identify vaccine recipients and cases of HZ and PHN. The end date of the follow-up period and the reason to end the follow-up were defined to avoid underestimating the incidence. The analysis was stratified according to age, sex, immunocompromising conditions, and use of immunosuppressant therapy. Vaccine effectiveness was estimated using published estimates of the incidence of HZ and PHN in the unvaccinated population in Japan.

RESULTS

A total of 1175 patients were enrolled in the study. During a median follow-up period of 3.36 years, HZ was diagnosed in 27 participants (15 men [2.8%] and 12 women [1.9%]). The incidence of HZ among VVL (BIKEN) recipients was 7.67/1000 person-years. The incidence of PHN was 0.82/1000 person-years. The vaccine effectiveness was estimated as 27.8% [95% confidence interval (CI), -29.8 to 63.9%] and 73.8% [95% CI, 38.6-100%] against HZ and PHN, respectively.

CONCLUSIONS

The VVL (BIKEN) had limited effectiveness at preventing HZ, but relatively good effectiveness at preventing PHN. VVL (BIKEN) might have a role as an affordable alternative.

Alleviating effect of lavender (Lavandula angustifolia) and its major components on postherpetic pain: a randomized blinded controlled trial

BACKGROUND

Postherpetic neuralgia (PHN) causes severe pain which can lead to decreased quality-of-life. This study aimed to evaluate the effects of inhalation of lavender (Lavandula angustifolia) oil and its major components (linalool and linalyl acetate) on the pain in patients with PHN.

METHODS

This study was performed at an outpatient clinic. Sixty-four patients with postherpetic neuralgia were randomly allocated to a control group (almond oil) or one of three experimental groups (lavender oil, linalool, or linalyl acetate diluted in almond oil at concentration of 1% v/v), and the participants inhaled the aroma by natural breathing. Quality, severity, and intensity of pain were measured before and after the intervention.

RESULTS

Six patients discontinued the intervention for personal reasons; hence, data from 58 patients were analyzed (control group, n = 14; 1% lavender oil group, n = 15; 1% linalool, n = 15; 1% linalyl acetate, n = 14). Reduction in sensory pain was greater in the 1% lavender oil group, 1% linalool group, and 1% linalyl acetate group than in the control group (all P < 0.001). Reduction in affective pain was greater in the 1% lavender group (P < 0.001) and the 1% linalool group (P = 0.007) than in the control group. Decreases in pain severity and intensity were significantly greater in all three intervention groups than in the control group.

CONCLUSIONS

Inhalation of lavender oil and its major volatile components effectively reduced the quality, severity, and intensity of postherpetic pain, suggesting that lavender oil, linalool, and linalyl acetate may each be an effective intervention for reducing pain in patients with postherpetic neuralgia.

TRIAL REGISTRATION

This study was retrospectively registered on the Clinical Research Information Service.

REGISTRATION NUMBER

KCT0007772, first registration 06/10/2022.

Incidence and Burden of Herpes Zoster in Sweden: A Regional Population-Based Register Study

INTRODUCTION

Herpes zoster (HZ) is a painful disease that mainly affects individuals whose immune system has been weakened because of increasing age (> 50 years) or certain diseases or treatments. We estimated the complete burden of HZ.

METHODS

This population-based register study analysed healthcare data from the VEGA and Digitalis databases of Västra Götaland Region (VGR), Sweden. The VEGA database includes all patients in VGR, covering both hospital and primary care. The Digitalis records prescribed medications. The study population included patients aged ≥ 18 years with at least one registered primary or secondary HZ diagnosis (based on International Classification of Diseases [ICD] codes) between 2005 and 2021. Incidence rates (95% confidence intervals [CI]) were stratified by age, sex and diagnosis/analgesic prescription.

RESULTS

Overall HZ incidence increased from 2.5 (95% CI 2.4-2.6) in 2005 to 4.2 (95% CI 4.1-4.3) in 2021. The increase in incidence was rapid from 2005 to 2013, followed by a plateauing trend. From 2014-2019, the lifetime risk of HZ, excluding recurrent cases, was 36.5% (95% CI 35.5-37.4%). Municipal differences ranged from 34.4% (95% CI 32.5-36.4%) to 43.6% (95% CI 39.9-47.4%). Recurrence rates of HZ were 8.7% and 9.1% with follow-up periods of 5.5 and 10.5 years, respectively. Reported postherpetic neuralgia (PHN) cases increased five-fold over the study period. In 2019, 19% of all HZ patients developed HZ-related neuropathic pain; 13.6% had signs of persistent pain (> 90 days; i.e. PHN). An increased occurrence of cerebral and cardiovascular disease was observed in HZ patients. Among high-risk groups the occurrence of HZ peaked among those with inflammatory and autoimmune diseases.

CONCLUSION

HZ and PHN risk in Sweden is comparable to that in other European countries prior to implementing HZ national vaccination programs. Municipal differences suggest that the lifetime risk of HZ in Sweden is at least 36.5%.

CLINICAL TRIAL REGISTRATION

NCT Number ( www.

CLINICALTRIALS

gov ).

Medication Management of Neuropathic Pain Disorders

It is important for Oral and Maxillofacial Surgeons to be familiar with the various neuropathic facial pain disorders and their appropriate treatments. Neuropathic pain can be characterized by the nature of the pain experienced by patients; episodic or continuous. Episodic neuropathic pain disorders include trigeminal neuralgia and glossopharyngeal neuralgia. Continuous neuropathic pain disorders compromise of disorders such as idiopathic trigeminal neuralgia, postherpetic neuralgia, central post-stroke pain, and complex regional pain syndrome. Various forms of pharmacologic management exist for these neuropathic pain disorders.

Chronic Respiratory Diseases as a Risk Factor for Herpes Zoster Infection

INTRODUCTION

Herpes zoster (HZ) is a condition that results from the reactivation of the varicella zoster virus (VZV). Several diseases have been reported to increase the risk of developing HZ and postherpetic neuralgia (PHN). The objective of this study is to analyze the prevalence and risk factors for HZ and PHN in the most frequent chronic respiratory diseases, which are chronic obstructive pulmonary disease (COPD), asthma, lung cancer and obstructive sleep apnea (OSA).

METHODS

We conducted an observational, retrospective, non-interventional study between January 2012 and December 2020 based on data from the Castilla-La Mancha Regional Health System in Spain. We used the Savana Manager 3.0 artificial intelligence-enabled system to collect information from electronic medical records.

RESULTS

31765 subjects presented a diagnosis of HZ. Mean age was 64.5 years (95%CI 64.3-64.7), and 58.2% were women. The prevalence of HZ showed an increasing trend in patients over the age of 50. A risk analysis adjusted for sex and comorbidities in COPD, asthma, lung cancer and OSA presented a higher risk of developing HZ in the first three (OR 1.16 [95%CI 1.13-1.19], 1.67 [1.63-1.71], 1.68 [1.60-1.76], respectively), which further increased in all three when associated with comorbidities. Regarding postherpetic neuralgia, an increased risk was only observed related to COPD and lung cancer (OR 1.24 [95%CI 1.23-1.25], 1.14 [1.13-1.16], respectively), further increasing when associated with comorbidities.

CONCLUSIONS

In a standard clinical practice setting, the most prevalent respiratory diseases (asthma, COPD and lung cancer) are related to a higher risk of HZ and PHN. These data are fundamental to assess the potential impact of vaccination in this population.

Foreign Body Granuloma Following Hwangryunhaedok-tang Pharmacopuncture for Postherpetic Neuralgia

Foreign body granuloma can be caused by endogenous compounds as well as various injectable materials. In oriental medicine, pharmacopuncture combining herbal medicine administration and injection is one of the commonly used procedures. Hwangryunhaedok-tang (HHT, a.k.a., Huang-Lian-Jie-Du-Tang in China), an oriental medicinal herb known to produce anti-inflammatory effects, has been recently made in pharmacopuncture products and commonly used for various disorders. An 88-year-old female presented with multiple tender nodules on the left parietal scalp and forehead. The diagnosis of foreign body granuloma caused by HHT pharmacopuncture was revealed by more detailed previous treatment history of postherpetic neuralgia and histopathologic examination. Herein, we report a foreign body granuloma as a delayed adverse reaction caused by non-standard administration of herbal extracts, considered biologically inert.

Interpeduncular cistern intrathecal targeted drug delivery for intractable postherpetic neuralgia: A case report

BACKGROUND

Intractable postherpetic neuralgia (PHN) can be difficult to manage even with aggressive multimodal therapies. Patients who experience uncontrolled refractory cranial PHN despite conservative treatment may benefit from an intrathecal drug delivery system (IDDS). For craniofacial neuropathic pain, the traditional approach has been to place the intrathecal catheter tip below the level of the cranial nerve root entry zones, which may lead to insufficient analgesia.

CASE SUMMARY

We describe a 69-year-old man with a 1-year history of PHN after developing a vesicular rash in the ophthalmic division of cranial nerve V (trigeminal nerve) distribution. The pain was rated 7-8 at rest and 9-10 at breakthrough pain (BTP) on a numeric rating scale. Despite receiving aggressive multimodal therapies including large doses of oral analgesics (gabapentin 150 mg q12 h, oxycodone 5 mg/acetaminophen 325 mg q6 h, and lidocaine 5% patch 700 mg q12 h) and sphenopalatine ganglion block, there was no relief of pain. Subsequently, the patient elected to have an implantable IDDS with the catheter tip placed at the interpeduncular cistern. The frequency of BTP episodes decreased. The patient's continuous daily dose was adjusted to 0.032 mg/d after 3 mo of follow-up and stopped 5 mo later. He did not report pain or other discomfort at outpatient follow-up 6 mo and 1 year after stopping intracisternal hydromorphone.

CONCLUSION

The use of interpeduncular cistern intrathecal infusion with low-dose hydromorphone by IDDS may be effective for severe craniofacial PHN.

Alterations of the gut microbiota in patients with postherpetic neuralgia

Postherpetic neuralgia (PHN) is a prevalent, intricate, and intractable form of neuropathic pain. The available evidence indicates that alterations in the gut microbiota are significant environmental determinants in the development of chronic neuropathic pain. Nevertheless, the correlation between the gut microbiota and PHN remains elusive. A cross-sectional study was performed on a cohort of 27 patients diagnosed with PHN and 27 matched healthy controls. Fecal samples were collected and subjected to microbiota analysis using 16S ribosomal RNA gene sequencing. Comparable levels of bacterial richness and diversity were observed in the gut microbiota of PHN patients and healthy controls. A significant difference was observed in 37 genera between the two groups. Furthermore, the LEfSe method revealed that the abundance levels of Escherichia-Shigella, Streptococcus, Ligilactobacillus, and Clostridia_UCG-014_unclassified were elevated in PHN patients, while Eubacterium_hallii_group, Butyricicoccus, Tyzzerella, Dorea, Parasutterella, Romboutsia, Megamonas, and Agathobacter genera were reduced in comparison to healthy controls. Significantly, the discriminant model utilizing the predominant microbiota exhibited efficacy in distinguishing PHN patients from healthy controls, with an area under the curve value of 0.824. Moreover, Spearman correlation analysis demonstrated noteworthy correlations between various gut microbiota and clinical symptoms, including disease course, anxiety state, sleep quality, heat pain, pain intensity, and itching intensity. Gut microbiota dysbiosis exists in PHN patients, microbiome differences could be used to distinguish PHN patients from normal healthy individuals with high sensitivity and specificity, and altered gut microbiota are related to clinical manifestations, suggesting potentially novel prevention and therapeutic directions of PHN.

Role of autophagy in the pathogenesis and regulation of pain

Pain is a ubiquitous and highly concerned clinical symptom, usually caused by peripheral or central nervous injury, tissue damage, or other diseases. The long-term existence of pain can seriously affect daily physical function and quality of life and produce great torture on the physiological and psychological levels. However, the complex pathogenesis of pain involving molecular mechanisms and signaling pathways has not been fully elucidated, and managing pain remains highly challenging. As a result, finding new targets to pursue effective and long-term pain treatment strategies is required and urgent. Autophagy is an intracellular degradation and recycling process that maintains tissue homeostasis and energy supply, which can be cytoprotective and is vital in maintaining neural plasticity and proper nervous system function. Much evidence has shown that autophagy dysregulation is linked to the emergence of neuropathic pain, such as postherpetic neuralgia and cancer-related pain. Autophagy has also been connected to pain caused by osteoarthritis and lumbar disc degeneration. It is worth noting that in recent years, studies on traditional Chinese medicine have also proved that several traditional Chinese medicine monomers involve autophagy in the mechanism of pain relief. Therefore, autophagy can serve as a potential regulatory target to provide new ideas and inspiration for pain management.

Therapeutic Strategies for Postherpetic Neuralgia: Mechanisms, Treatments, and Perspectives

PURPOSE OF REVIEW

Postherpetic neuralgia is an annoying pain that mainly affects older people. In order to give patients more options, this review summarizes the pharmacological and interventional treatments for postherpetic neuralgia and updates the research on the efficacy, thereby providing doctors with more treatment options. The adverse effects and effective doses of its various treatments are also presented so that the therapy can be prescribed according to their concrete physical conditions. In a word, this review is dedicated to providing a comprehensive overview of the treatment options for postherpetic neuralgia and offering patients more choices.

RECENT FINDINGS

Combinational therapy is more excellent than monotherapy. The local anesthesia and gabapentin comprised outstanding compatibility. In addition, two therapeutic tools for PHN patients, especially for the intractable ones, electroacupuncture (EA), and osteopathic manipulative treatment (OMT), show their efficacy and become potential options to alleviate pain. In terms of treatment, guidelines recommend patients use tricyclic antidepressants (TCAs), gabapentin, pregabalin, and 5% lidocaine patches as the first-line medications, and gabapentin is investigated most, especially the gabapentin enacarbil (GEn). And drug efficacy can be limited by adverse effects and tolerated doses. Interventional treatments, with their invasiveness and operational difficulty, are usually considered for intractable patients. Combinational therapies may be used when a single therapy cannot achieve the desired effect. Therapies such as OMT and EA have also been proposed to palliate pain in some cases, and future directions of treatment may be investigated in Chinese medicine and acupuncture.

Evaluation of the correlation of dorsal root ganglia and spinal nerves with clinical symptoms in patients with postherpetic neuralgia using magnetic resonance neurography

Purpose

To assess changes of dorsal root ganglia (DRG) and spinal nerves in patients with postherpetic neuralgia (PHN), and investigate the correlation between DRG morphology and clinical symptoms in PHN patients using magnetic resonance neurography (MRN).

Methods

In this case-control study, forty-nine lesioned DRG in 30 patients and 49 normal DRG in 30 well-matched (age, sex, height, weight) healthy controls were assessed. Clinical symptoms of patients (pain, allodynia, itching, and numbness) were assessed. MRN features (DRG volume (VDRG), the largest diameter (Dmax) of spinal nerves, signal intensity of DRG and spinal nerves (M-value)) were measured in all participants. Multilinear regression analysis was used to evaluate the relationship between the DRG morphology and clinical symptoms in patients.

Results

The volume and relative M-value of lesioned DRG in patients were significantly higher than those on the same side of healthy controls (p = 0.013, p < 0.001, respectively). The mean Dmax and relative M-value of spinal nerves on the lesioned side were significantly higher than those on the contralateral and same side of healthy controls (p < 0.0001, p = 0.0001, p = 0.0011, p = 0.0053, respectively). No difference was found between the mean VDRG of the lesioned and contralateral sides. Multiple linear regression analysis revealed that disease duration was independent risk factor for the maximum rate of VDRG differences (p = 0.013).

Conclusions

DRG and spinal nerves on the lesioned side are swollen during PHN. Disease duration is an independent risk factor for morphological differences in the lesioned DRG of PHN patients. This study provides important guidance for individualized treatments of PHN.

Evaluating public interest in herpes zoster in Germany by leveraging the internet: a retrospective search data analysis

BACKGROUND

Herpes zoster (HZ) and its complication postherpetic neuralgia (PHN), whose incidence are both expected to increase with an ageing population, have demonstrated high costs on healthcare systems and burden on individual quality of life. Previous studies have shown the possibility of assessing public interest in a disease and factors that influence search behaviour using internet search data. The aim of this study was to analyze internet search data for HZ in Germany to evaluate public interest in the disease and relevant influential temporal and geographic factors that modify search behavior.

METHODS

Google Ads Keyword Planner was used to generate a list of HZ-related keywords including their search volume for Germany as a whole and its sixteen federal states from October 2016 to September 2020. All keywords were qualitatively categorized, and changes over time and correlations with population density, physician density, and vaccination rates were assessed using Welch's ANOVA, Bonferroni correction for post-hoc analyses, and Pearson's correlation.

RESULTS

A total of 1,651 relevant keywords with a search volume of 20,816,210 searches were identified. Overall, national search volume increased each year of the study period with a peak in August 2020. More than half of the total search volume related to general queries (55.1%). The highest average monthly search volumes were observed in the states of Hamburg, Saarland, and Bremen. Average monthly search volume showed strong positive correlations with population density (r = .512, p = .043) and a strong negative correlation with the number of inhabitants per working physician (r = -.689, p = .003).

CONCLUSIONS

The study demonstrated that evaluating internet search data is a viable method for assessing public interest in HZ, thereby identifying areas of unmet need to support targeted public health campaigns.

Correlation between pain catastrophizing in acute herpes zoster and postherpetic neuralgia: a retrospective analysis

PURPOSE

The objective of this study was to examine the association between pain catastrophizing in acute phase herpes zoster and the development of postherpetic neuralgia.

METHODS

The medical records of all patients diagnosed with herpes zoster between February 2016 and December 2021 were retrieved. Inclusion criteria were patients aged > 50 years who visited our pain center within 60 days after rash onset and reported a pain intensity of ≥ 3 in a numerical rating scale. Patients with a score of 30 or more in the pain catastrophizing scale at baseline were assigned to the catastrophizer group, and those with a score < 30 were assigned to the non-catastrophizer group. We defined patients with "postherpetic neuralgia" and "severe postherpetic neuralgia" as those with a numerical rating scale score of 3 or more and 7 or more at 3 months after baseline, respectively.

RESULTS

Data of 189 patients were available for complete analysis. Age, baseline numerical rating scale, and prevalence of anxiety and depression were significantly higher in the catastrophizer than those in the non-catastrophizer group. Incidence of postherpetic neuralgia did not differ significantly between the groups (p = 0.26). Multiple logistic regression analysis showed that age, severe pain at baseline, and immunosuppressive state were the factors which were independently associated with developing postherpetic neuralgia. Severe pain at baseline was the only factor related to developing severe postherpetic neuralgia.

CONCLUSION

Pain catastrophizing in the acute phase of herpes zoster may not be related to the development of postherpetic neuralgia.

Randomized, Placebo-Controlled, Multicenter Clinical Study on the Efficacy and Safety of Lidocaine Patches in Chinese Patients with Postherpetic Neuralgia

INTRODUCTION

To evaluate the efficacy and safety of lidocaine patches in Chinese patients with postherpetic neuralgia (PHN).

METHODS

Patients were randomized to receive lidocaine patches or placebo every day for 4 weeks. Efficacy endpoints included the decrease of analogue scale score (VAS) value at week 4, 2 and 1 and the percentage of patients that achieved a 30% decrease of VAS value. Safety analyses were conducted as well.

RESULTS

Two hundred forty Chinese patients were randomized. At week 1, lidocaine patch-treated patients had a higher clinical response versus placebo, and at week 4, the mean (SD) decreases of VAS value compared to the baseline were 14.01 (14.35) in the treatment group and 9.36 (12.03) in the placebo group (p = 0.0088). Overall, the safety profile in the treatment group was consistent with that observed in the placebo group [adverse event (AE) incidence rate: 33.33% versus 37.29%, p = 0.5857].

CONCLUSIONS

Lidocaine patches resulted in improved clinical response versus placebo in the treatment of PHN patients and were well tolerated.

Status of Herpes Zoster and Herpes Zoster Vaccines in 2023: A position paper

Herpes zoster infection (HZ) is an important public health problem due to its high incidence and frequent complications, especially post-herpetic neuropathy . The incidence of HZ increases with age and is more frequent in immunocompromised patients. It is estimated that at least 60,000 people develop HZ each year in Spain. The usual forms of HZ are so clinically characteristic that they do not usually require microbiological confirmation, which is reserved for cases without cutaneous manifestations or with atypical presentation. There are currently two vaccines approved by the regulatory agencies and marketed in Spain to prevent the onset of HZ and its complications. The first (Zostavax®) was marketed by the company MSD and licensed in Europe in 2006 and is a live attenuated virus vaccine that is administered in a single dose, while the second (Shingrix®) is a recombinant vaccine, marketed in 2017 and requires two doses. While the former cannot be administered to immunocompromised persons, the latter can be prescribed to any group of adults. The criteria for the indication and financing of these vaccines have not been uniform in the various autonomous communities of Spain. These and other aspects of HZ have been discussed by a group of experts from the Illustrious Official College of Physicians of Madrid (ICOMEM) whose criteria and opinions are included in this paper.

Treatment of postherpetic neuralgia by bone marrow aspirate injection: A case report

BACKGROUND

Postherpetic neuralgia (PHN) is the most frequent and a difficult-to-treat complication of herpes zoster (HZ). Its symptoms include allodynia, hyperalgesia, burning, and an electric shock-like sensation stemming from the hyperexcitability of damaged neurons and varicella-zoster virus-mediated inflammatory tissue damage. HZ-related PHN has an incidence of 5%–30%, and in some patients, the pain is intolerable and can lead to insomnia or depression. In many cases, the pain is resistant to pain-relieving drugs, necessitating radical therapy.

CASE SUMMARY

We present the case of a patient with PHN whose pain was not cured by conventional treatments, such as analgesics, block injections, or Chinese medicines, but by bone marrow aspirate concentrate (BMAC) injection containing bone marrow mesenchymal stem cells. BMAC has already been used for joint pains. However, this is the first report on its use for PHN treatment.

CONCLUSION

This report reveals that bone marrow extract can be a radical therapy for PHN.

Utilization of Truncal Fascial Plane Nerve Blocks for Chronic Pain Management: A Narrative Review

PURPOSE OF REVIEW

Nerve blocks constitute an integral portion in the management of chronic pain. The widespread use of ultrasound imaging opened the door to a flood of newer blocks especially truncal plane nerve blocks. We reviewed the current medical literature for studies and case reports utilizing the two most common truncal plane nerve blocks, transversus abdominis plane and erector spinae plane blocks, to manage chronic pain.

RECENT FINDINGS

We found some evidence, mostly in case reports and retrospective observational studies, that supports the use of transversus abdominis plane and erector spinae plane nerve blocks, usually with steroids, as a safe and valuable part of interdisciplinary management of chronic abdominal and chest walls pain. Ultrasound-guided truncal fascial plane nerve blocks are safe, easy to learn, and proven to help with post-operative acute pain management. Although limited, our current review provides evidence from the current medical literature regarding the utility of these blocks to manage some of the challenging chronic and cancer-related pain conditions of the trunk region.

Intradermal miR-16-5p targets Akt3 and reduces RTX-induced postherpetic neuralgia-mimic pain in mice

The molecular mechanisms of refractory pain in postherpetic neuralgia (PHN) patients are not fully understood. PHN may be related to skin abnormality after herpes zoster induced skin lesions. We previously reported 317 differentially expressed microRNAs (miRNAs) in PHN skin compared with the contralateral normal mirror skin. In this study, 19 differential miRNAs were selected and the expression was validated in other 12 PHN patients. The expression levels of miR-16-5p, miR-20a-5p, miR-505-5p, miR-3664-3p, miR-4714-3p and let-7a-5p are lower in PHN skin, which is the same as those in microarray experiment. To evaluate the effects of cutaneous miRNA on PHN, the expression of candidate miRNAs is further observed in resiniferatoxin (RTX) induced PHN-mimic mice model. In the plantar skin of RTX mice, miR-16-5p and let-7a-5p are downregulated, with the same expression trend of PHN patients. In addition, intraplantar injection of agomir-16-5p reduced mechanical hyperalgesia, and improved thermal hypoalgesia in RTX mice. Furthermore, agomir-16-5p down-regulated the expression levels of Akt3, which is the target gene of agomir-16-5p. These results suggest that intraplantar miR-16-5p may alleviate RTX induced PHN-mimic pain by inhibiting the expression of Akt3 in the skin.

Herpes zoster vaccine effectiveness against herpes zoster and postherpetic neuralgia in New Zealand: a retrospective cohort study

BACKGROUND

Herpes zoster (HZ) and associated complications cause significant burden to older people. A HZ vaccination programme was introduced in Aotearoa New Zealand in April 2018 with a single dose vaccine for those aged 65 years and a four-year catch up for 66-80 year-olds. This study aimed to assess the 'real-world' effectiveness of the zoster vaccine live (ZVL) against HZ and postherpetic neuralgia (PHN).

METHODS

We conducted a nationwide retrospective matched cohort study from 1 April 2018 to 1 April 2021 using a linked de-identified patient level Ministry of Health data platform. A Cox proportional hazards model was used to estimate ZVL vaccine effectiveness (VE) against HZ and PHN adjusting for covariates. Multiple outcomes were assessed in the primary (hospitalised HZ and PHN - primary diagnosis) and secondary (hospitalised HZ and PHN: primary and secondary diagnosis, community HZ) analyses. A sub-group analysis was carried out in, adults ≥ 65 years old, immunocompromised adults, Māori, and Pacific populations.

FINDINGS

A total of 824,142 (274,272 vaccinated with ZVL matched with 549,870 unvaccinated) New Zealand residents were included in the study. The matched population was 93.4% immunocompetent, 52.2% female, 80.2% European (level 1 ethnic codes), and 64.5% were 65-74 years old (mean age = 71.1±5.0). Vaccinated versus unvaccinated incidence of hospitalised HZ was 0.16 vs. 0.31/1,000 person-years and 0.03 vs. 0.08/1000 person-years for PHN. In the primary analysis, the adjusted overall VE against hospitalised HZ and hospitalised PHN was 57.8% (95% CI: 41.1-69.8) and 73.7% (95% CI:14.0-92.0) respectively. In adults ≥ 65 years old, the VE against hospitalised HZ was 54.4% (95% CI: 36.0-67.5) and VE against hospitalised PHN was 75·5% (95% CI: 19.9-92.5). In the secondary analysis, the VE against community HZ was 30.0% (95% CI: 25.6-34.5). The ZVL VE against hospitalised HZ for immunocompromised adults was 51.1% (95% CI: 23.1-69.5), and PHN hospitalisation was 67.6% (95% CI: 9.3-88.4). The VE against HZ hospitalisation for Māori was 45.2% (95% CI: -23.2-75.6) and for Pacific Peoples was 52.2% (95% CI: -40.6 -83·7).

INTERPRETATION

ZVL was associated with a reduction in risk of hospitalisation from HZ and PHN in the New Zealand population.

FUNDING

Wellington Doctoral Scholarship awarded to JFM.

A Meta-analysis of Randomized Controlled Trials Comparing the Efficacy and Safety of Pregabalin and Gabapentin in the Treatment of Postherpetic Neuralgia

OBJECTIVE

To systematically evaluate the clinical efficacy of pregabalin and gabapentin in the treatment of postherpetic neuralgia (PHN), including the difference in pain control and occurrence of adverse reactions.

METHODS

PubMed, MEDLINE, EMBASE, Cochrane Library, and Web of Science databases were searched for randomized controlled trials (RCTs) comparing the efficacy of pregabalin and gabapentin in patients with PHN. Data from studies meeting the inclusion criteria were extracted and the Cochrane Risk of Bias risk assessment tool was used to evaluate the quality of the included studies. Revman 5.3 and Stata17 were used to perform the meta-analysis and to detect publication bias.

RESULTS

A total of 14 RCTs with 3545 patients were included in this study, including 926 in the pregabalin treatment group, 1256 in the gabapentin treatment group, and 1363 in the placebo control group. Pregabalin was better than gabapentin in alleviating pain and improving the global perception of change in pain and sleep (P < 0.05). Gabapentin was associated with a lower incidence of adverse events than pregabalin (P < 0.05). Funnel plot and Begg's and Egger's tests showed no significant publication bias.

CONCLUSION

Pregabalin appears to have a better overall therapeutic effect than gabapentin for patients with PHN, but gabapentin has a lower incidence of adverse reactions and a better safety profile. Clinicians should comprehensively consider patient factors and fully evaluate the advantages and disadvantages of each treatment option to select the most suitable drugs for patient use. Considering the limited quantity and quality of the existing literature, high-quality RCTs are needed to confirm the advantages of pregabalin over gabapentin in the treatment of PHN and guide clinical decision-making.

Herpes zoster after COVID-19 vaccination, aspect of pain medicine: a retrospective, single-center study

BACKGROUND

Herpes zoster (HZ) is one of the most common cutaneous adverse reactionsassociated with the coronavirus disease 2019 (COVID-19) vaccine and has been widely reported. This study aimed to evaluate HZ following COVID-19 vaccination from the viewpointof pain management.

METHODS

A retrospective study was conducted on 42 patients with HZ who visited the painclinic between August 2021 and October 2021. Medical records were reviewed to comparepain severity, treatment methods, treatment duration, and incidence rate of postherpeticneuralgia (PHN) in patients who received COVID-19 vaccination within 6 weeks prior to developing symptoms compared with other patients with HZ.

RESULTS

Fourteen patients developed HZ within 6 weeks after vaccination and were significantly younger than the other HZ groups. There were no significant differences in the frequency of prodromal pain, location of pain, pain severity, treatment methods, treatmentduration, or incidence of PHN compared with the other HZ groups.

CONCLUSIONS

COVID-19 vaccination-related HZ showed clinical features similar to those ofthe other HZ.

A Guide to Preclinical Models of Zoster-Associated Pain and Postherpetic Neuralgia

Reactivation of latent varicella-zoster virus (VZV) causes herpes zoster (HZ), which is commonly accompanied by acute pain and pruritus over the time course of a zosteriform rash. Although the rash and associated pain are self-limiting, a considerable fraction of HZ cases will subsequently develop debilitating chronic pain states termed postherpetic neuralgia (PHN). How VZV causes acute pain and the mechanisms underlying the transition to PHN are far from clear. The human-specific nature of VZV has made in vivo modeling of pain following reactivation difficult to study because no single animal can reproduce reactivated VZV disease as observed in the clinic. Investigations of VZV pathogenesis following primary infection have benefited greatly from human tissues harbored in immune-deficient mice, but modeling of acute and chronic pain requires an intact nervous system with the capability of transmitting ascending and descending sensory signals. Several groups have found that subcutaneous VZV inoculation of the rat induces prolonged and measurable changes in nociceptive behavior, indicating sensitivity that partially mimics the development of mechanical allodynia and thermal hyperalgesia seen in HZ and PHN patients. Although it is not a model of reactivation, the rat is beginning to inform how VZV infection can evoke a pain response and induce long-lasting alterations to nociception. In this review, we will summarize the rat pain models from a practical perspective and discuss avenues that have opened for testing of novel treatments for both zoster-associated pain and chronic PHN conditions, which remain in critical need of effective therapies.

Refractory postherpetic neuralgia in a multiple myeloma patient with lenalidomide maintenance therapy: a case report

Herpes zoster is not common in multiple myeloma (MM) patients treated with lenalidomide-based regimens. We report an MM patient in his late 60s who received lenalidomide as maintenance treatment and whose condition was complicated with refractory postherpetic neuralgia. The patient received antiviral treatment and analgesia immediately after the diagnosis of herpes zoster. Two months later, the patient received acupuncture, radiofrequency treatment, and even spinal cord stimulation, which failed to relieve the pain. Consequently, we performed high-resolution magnetic resonance imaging of the cervical and thoracic nerves. Then, stellate ganglion block, left C5/C6/C7/C8 nerve root block, and left thoracic 1, 2 paravertebral nerve block were performed with the assistance of real-time ultrasound. The pain was immediately relieved after treatment; however, the symptoms reappeared 2 days later. At 5 months after treatment, the patient still experienced severe pain. We suggest that MM patients complicated with postherpetic neuralgia are refractory to treatment. Starting nerve block therapy, pulsed radiofrequency, and other interventional therapies as early as possible could be a more optimal treatment plan for these patients.

Analysis of Efficacy and Factors Associated with Reccurence After Radiofrequency Thermocoagulation in Patients with Postherpetic Neuralgia: a Long-Term Retrospective and Clinical Follow-Up Study

INTRODUCTION

Postherpetic neuralgia (PHN) is a painful condition that persists for 1 month or more after herpes zoster rash has healed. Radiofrequency thermocoagulation (RF-TC) provides analgesia by destroying the dorsal root ganglion and blocking the pain upload pathway; nonetheless, the concomitant neurological-related side effects and recurrence remain a concern.

METHODS

In this study, 228 patients with PHN in the thoracic segment treated with RF-TC of the dorsal root ganglion of the spinal nerve were included, and were followed up regularly after surgery. The numerical rating scale (NRS) scores, time to recurrence, and intraoperative and postoperative adverse events were recorded and analyzed. The Kaplan-Meier method was used to plot survival curves and calculate the cumulative effective rate and recurrence rate. Cox regression analyses were performed to identify factors associated with postoperative recurrence. Predictive models were built to assess the value of applications.

RESULTS

The NRS scores decreased in all postoperative periods compared with preoperative ones. At 10-year-follow-up, recurrence was observed in 34.6% (79/228) of patients that underwent PHN. The main postoperative complications were numbness and reduced abdominal muscle strength, which gradually decreased with time, while the abdominal muscle strength gradually recovered. No other adverse events occurred. Interval-censored multivariable Cox regression analysis demonstrated that disease course, complications, pain grade, and type of RF electrode were associated with a significantly higher risk of relapse. The main intraoperative adverse effect was a transient increase in pain during RF-TC.

CONCLUSION

CT-guided RF-TC of the dorsal root ganglion of the spinal nerve for PHN is a relatively safe and effective surgical option. Disease course, type of RF electrode, complications, and pain grade are risk factors for postoperative recurrence and can assist in clinical decision-making before the RF-CT procedure.

Treatment Efficacy and Technical Advantages of Temporary Spinal Nerve Root Stimulation Compared to Traditional Spinal Cord Stimulation for Postherpetic Neuralgia

BACKGROUND

Postherpetic neuralgia (PHN) is a common complication after herpes zoster infection. While conventional dorsal column temporary spinal cord stimulation (tSCS) has been shown as an effective treatment option for this pain condition, recent data suggests ipsilateral temporary spinal nerve root stimulation (tSNRS) as a safe alternative for treating PHN. However, there is no direct clinical comparison between the newer tSNRS and the traditional tSCS.

OBJECTIVES

The current retrospective study aimed to describe the technical factors and the therapeutic efficacy of tSNR for patients with unilateral PHN and to compare these parameters with those treated with tSCS.

STUDY DESIGN

Retrospective cohort study.

SETTING

Single-center study in a large academic hospital.

METHODS

One hundred sixty patients with unilateral PHN who underwent 7-14 days of tSCS (n = 109) or tSNRS (n = 51) treatment were included. Technical factors between the 2 groups, such as procedure time, radiation dosage, number of electrodes used, number of stimulation parameter adjustments, and average cost, were compared. Treatment efficacy, measured by analgesic coverage, pain visual analog scale (VAS), total analgesic agent consumption, Pittsburgh sleep quality index (PSQI), and physical and mental quality of life, were also compared between the 2 groups at baseline, post-procedure, and 3 months after stimulation treatment.

RESULTS

Patients who underwent tSNRS reported significant improvement in pain level, sleep quality, and overall quality of life immediately postprocedure and during the follow-up period. This therapeutic effect was comparable to the tSCS group. Moreover, tSNRS achieved this therapeutic effect with a fewer number of implanted electrodes and stimulation adjustments than tSCS. The precision and consistency of the tSNRS technique were associated with a significant overall lower cost, a shorter procedure time, and less intraoperative radiation exposure in the tSNRS group than in those who received tSCS.

LIMITATIONS

The current retrospective cohort study was limited by its relatively short follow-up period. Also, the selection of stimulation techniques was not randomized.

CONCLUSIONS

While tSNRS provides similar therapeutic efficacy compared to tSCS for patients with unilateral PHN; it offers several technical advantages. These advantages include shorter procedure time, less radiation exposure, fewer implanted electrodes, more effective stimulation, and lower overall cost.

Trigeminal extracranial thermocoagulation along with patient-controlled analgesia with esketamine for refractory postherpetic neuralgia after herpes zoster ophthalmicus: A case report

BACKGROUND

Primary trigeminal neuralgia can achieve satisfactory results through clinical treatment and intervention. The pathogenesis of neuralgia caused by varicella-zoster virus infection of the trigeminal nerve is more complex, and it is still difficult to relieve the pain in some patients simply by drug treatment or surgical intervention.

CASE SUMMARY

A 66-year-old woman was hospitalized with herpetic neuralgia after herpes zoster ophthalmicus (varicella-zoster virus infects the ophthalmic branch of the trigeminal nerve). On admission, the patient showed spontaneous, electric shock-like and acupuncture-like severe pain in the left frontal parietal region, and pain could be induced by touching the herpes area. The numerical rating scale (NRS) was 9. There was no significant pain relief after pulsed radiofrequency and thermocoagulation of the ophthalmic branch of the trigeminal nerve. Combined with patient-controlled intravenous analgesia (PCIA) with esketamine, neuralgia was significantly improved. The patient had no spontaneous pain or allodynia at discharge, and the NRS score decreased to 2 points. The results of follow-up 2 mo after discharge showed that the NRS score was ≤ 3, and the Pittsburgh Sleep Quality Index score was 5 points. There were no adverse reactions.

CONCLUSION

Trigeminal extracranial thermocoagulation combined with esketamine PCIA may be a feasible method for the treatment of refractory herpetic neuralgia after herpes zoster ophthalmicus.

A 1-Year Survey of Zoster-Associated Pain after Amenamevir Treatment

INTRODUCTION

Amenamevir is a new anti-varicella-zoster virus drug that inhibits the helicase-primase complex involved in viral replication. Amenamevir has the same effect as valaciclovir on acute pain and skin eruption, but no studies have examined the presence of long-term zoster-associated pain (ZAP) or postherpetic neuralgia (PHN) after amenamevir treatment.

METHODS

A total of 785 herpes zoster patients treated with amenamevir were followed up for 12 months. Patients recorded their pain status on a questionnaire once a month.

RESULTS

The proportion of patients with pain was 20.8% at 90 days, 8.0% at 180 days, 3.8% at 270 days, and 2.7% at 360 days after treatment. The median residual pain duration was 48 days. ZAP resolution rate slowed between 90 and 120 days, suggesting that the main feature of ZAP is a shift from nociceptive pain to neuropathic pain. Older age and more severe skin symptoms at the first visit were associated with a higher risk of developing PHN. Median ZAP duration was high for the head, face, and upper back and chest. Regarding the nature of pain, sudden pain attacks that felt like electric shocks, sensation of numbness, burning sensation, and cold/heat pain tended to remain as PHN.

CONCLUSIONS

Although conclusions must remain tentative without further comparative studies, amenamevir seems to have a similar effect on PHN as conventional nucleoside analogs, despite having a different action mechanism.

CLINICAL TRIAL REGISTRATION

UMIN000035938.

Support Vector Machine versus Multiple Logistic Regression for Prediction of Postherpetic Neuralgia in Outpatients with Herpes Zoster

BACKGROUND

Postherpetic neuralgia (PHN), as the most common complication of herpes zoster (HZ), is very refractory to current therapies. Studies of HZ have indicated that early aggressive pain interventions can effectively prevent PHN; therefore, accurately predicting PHN in outpatients with HZ and treating HZ promptly, would be of great benefit to patients. Multiple logistic regression (MLR) has often been used to predict PHN. However, support vector machine (SVM) has been poorly studied in predicting PHN in outpatients with HZ.

OBJECTIVE

The aim of our retrospective study was to analyze the data of outpatients with HZ to evaluate the use of SVM for predicting PHN by comparing it with MLR.

STUDY DESIGN

A retrospective study.

SETTING

Department of Anesthesiology in China.

METHODS

The data of 732 outpatients with HZ from January 1, 2015 to May 31, 2020 were reviewed. Risk factors for having PHN in outpatients with HZ were screened using least absolute shrinkage and selection operator (LASSO) algorithm. Then, SVM and MLR were used to predict PHN in outpatients with HZ based on screened risk factors. The data from 600 patients were used for training set and another 132 patients for test set. The receiver operating characteristic (ROC) curve was drawn from the 132 test set of patients. The prediction accuracy of the models was assessed using the area under curve (AUC).

RESULTS

The incidence of having PHN in outpatients with HZ was 19.4%. The risk factors selected by LASSO algorithm were gender, age, VAS scores, skin lesion area, initial treatment time, anxiety, sites of HZ (multiple skin lesions), types of HZ (bullous) and types of pain (knife cutting). The AUC for the SVM and MLR in test set were 0.884 versus 0.853. According to the ROC curve, the specificity and the sensitivity were 0.879 and 0.840 for SVM, and 0.780 and 0.840 for MLR, respectively.

LIMITATIONS

Retrospective study and relatively small sample size.

CONCLUSIONS

Both SVM and MLR had good discriminative power, but SVM has better performance in predicting PHN in outpatients with HZ, regarding the prediction accuracy and specificity.

[Herpes zoster-prevention, diagnosis, and treatment]

BACKGROUND

Herpes zoster (HZ) is a common skin disease resulting from a regionally limited reactivation of a latent infection with the varicella zoster virus (VZV). Despite its usually self-limiting course, HZ is associated with a considerable individual and public health burden of disease, particularly due to its high rate of postherpetic neuralgia (PHN).

OBJECTIVES

To improve knowledge of the current recommendations for the prevention, diagnosis and treatment.

MATERIALS AND METHODS

Narrative review and summary of current guideline recommendations.

RESULTS

In Germany, the recombinant VZV subunit zoster vaccine is recommended for all adults of 60+ years and for immunocompromised persons of 50+ years. The diagnosis of HZ is clinical; in case of uncertainty, laboratory investigations can help confirm the diagnosis. For patients with HZ ophthalmicus, HZ oticus or neurological complications, an interdisciplinary approach is advantageous. Antiviral treatment should be started as early as possible; various factors, including the duration and location of the disease, the patient's age and signs of a complicated course, serve to determine the indication to initiate an antiviral medication. The choice of the appropriate treatment depends, among other factors, on the intravenous availability, comorbidities and intake preferences. Early and sufficient analgesic treatment according to the WHO pain ladder and, if required, with anticonvulsant adjuvants is necessary to treat acute pain and to reduce the risk for PHN.

CONCLUSION

Implementation of the current recommendations for the prevention, diagnosis and treatment of HZ and PHN is important to reduce the high burden of disease and improve quality of life of the patients.

Dorsal root ganglion stimulation combined with spinal cord stimulation for effective treatment of postherpetic neuralgia - A case report

Background

Although spinal cord stimulation (SCS) can be a treatment option for intractable postherpetic neuralgia (PHN), obtaining proper stimulation at the thoracic dermatome is difficult. Dorsal root ganglion (DRG) stimulation may be an effective treatment for patients with insufficient efficacy in SCS only.

Case

A 54-year-old male with intractable PHN was referred to our clinic. Pain was localized to the distribution of the T1–3 dermatomes. SCS trial was conducted, and lead was placed within the epidural space over the C6–T1 level; however, the stimulation was inadequate for his pain site. Therefore, another lead was placed within the left T1 and T2 DRG for trial, and T1 DRG stimulation provided adequate stimulation. T1 DRG stimulation and SCS could cover the entire pain site with paresthesia, and his pain was decreased by over 50%.

Conclusions

DRG stimulation combined with SCS may be a good treatment option for intractable thoracic PHN.

Incidence of complications of herpes zoster in individuals on immunosuppressive therapy: A register-based population study

OBJECTIVES

Herpes zoster (HZ) exposes to alterations of the quality-of-life. HZ is more frequent in immunocompromised individuals, but whether immunosuppression is associated with a higher rate of complications is not well documented. We aimed to assess association between drug-induced immunosuppression and HZ complications.

METHODS

Data from a sample of the French healthcare claims from 01/01/2006 to 12/31/2018 were analyzed. Complicated zoster (CZ) was defined as a hospitalization with a code for HZ or the first-time dispensation of high-dose valacyclovir and specific neuralgia analgesics. Drug-induced immunosuppression was identified through medication dispensation. Risk ratios were calculated to compare incidences in exposed individuals (EI) and non-exposed to immunosuppressive therapy (NEI).

RESULTS

We identified 227 and 2838 CZ, accounting for an incidence of 178 per 100,000 person-year (95%CI[154.9-201.1]) and 51.7 per 100,000 person-year (95%CI[49.8-53.6]), in EI and NEI, respectively (risk ratio: 3.44 (95%CI[3.01-3.94]). Mean age was 66 years in both groups. CZ occurred after a median of 11.7 months (IQR[5.3-49.9]) of immunosuppressive therapy. Post-herpetic neuralgia (PHN) lasted at least 3 months in 32.6% and 22.5% of cases in EI and NEI, respectively (p=.01).

CONCLUSIONS

Drug-induced immunosuppression increases the risk of CZ and exposes to longer-lasting PHN. Figures provided in this study could help guide prophylaxis of HZ.

A Cross-Sectional Concept Elicitation Study to Understand the Impact of Herpes Zoster on Patients' Health-Related Quality of Life

Introduction

After a chickenpox infection, the varicella zoster virus lies dormant in nerve cells and can be reactivated in later life to cause herpes zoster (HZ), also called shingles, a painful rash that may result in persistent postherpetic neuralgia (PHN). Treatment options are limited, and HZ/PHN may have substantial negative effects on health-related quality of life (HRQoL). This qualitative cross-sectional study explored the subjective patient experience and impact on HRQoL of HZ and PHN in adults aged ≥ 50 years in Canada.

Methods

Patients were eligible for the study if they were aged at least 50 years and had been diagnosed with HZ by a healthcare practitioner 7–60 days earlier for HZ patients and 90–365 days earlier for PHN patients. Eligible patients were invited to participate in concept elicitation interviews by telephone. Data from the interviews were transcribed and analyzed to identify key concepts related to symptoms and impacts on the patients’ lives.

Results

A total of 32 patients participated, with a mean age of 61 years. Most (72%) were female. The most common symptoms reported were rash (n = 32), pain (n = 31), fatigue (n = 26), and itchiness (n = 20). The most commonly reported HRQoL domains affected were emotional functioning (n = 31), activities of daily living (n = 31), sleep (n = 29), physical functioning (n = 25) and hobbies (n = 21). A conceptual model was developed to summarize these symptoms and impacts.

Conclusion

HZ negatively affected many dimensions of patients’ HRQoL, particularly during the acute phase of illness. This qualitative study helps to broaden understanding of the subjective patient experience of HZ.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-021-00581-w.

Analgesic Effect of Electroacupuncture on Postherpetic Neuralgia: A Trial Protocol for a Multicenter Randomized Controlled Trial

INTRODUCTION

The chronic neuropathic pain associated with postherpetic neuralgia (PHN) can last for several months or even many years, seriously affecting the affected person's work, sleep, mood, and daily life activities. In generaly, current treatments for PHN are at best limited and unsatisfactory, and adverse reactions are common, especially in elderly patients. Electroacupuncture (EA) is widely used clinically to manage painful diseases, but there remains a lack of evidence to support the effectiveness of EA on PHN. This study is designed to assess the efficacy and safety of EA on PHN, and to provide evidence-based medical evidence for EA treatment of PHN.

METHODS

This multicenter, prospective, randomized controlled trial will recruit 448 patients with PHN at seven clinical centers. Multicenter stratified variable block randomization will be used, and the eligible patients will be randomly allocated in a ratio of 1:1 to the EA group or sham EA group. The EA group will receive 4 weeks of EA treatment, given as 30-min treatment sessions, once daily, 5 times per week, for a total of 20 treatments; the sham EA group will receive sham EA treatment under the same conditions.

PLANNED OUTCOMES

The primary outcome measure is the 11-point Numeric Rating Scale pain score at week 4. The secondary outcome measures, including mechanical pain threshold, pain area of PHN, average number of pain episodes, the short-form McGill Pain Questionnaire 2, Zoster Brief Pain Inventory, the Depression, Anxiety, and Positive Outlook Scale, Patient Global Impression of Change, safety of EA, and use of concomitant medications, among others. The primary analysis of the outcomes will be the mixed-effect model with repeated measurement between groups on an intent-to-treat population.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT04560361. Registered 23 September 2020 ( https://clinicaltrials.gov/ct2/show/NCT04560361?term=NCT04560361&draw=2&rank=1 ).

Transverse myelitis after infection with varicella zoster virus in patient with normal immunity: A case report

BACKGROUND

Varicella zoster virus (VZV) is a human neurotropic and double-stranded DNA alpha-herpes virus. Primary infection with VZV usually occurs during childhood, manifesting as chickenpox. Reactivation of latent VZV can lead to various neurological complications, including transverse myelitis (TM); although cases of the latter are very rare, particularly in newly active VZV infection.

CASE SUMMARY

We report here an unusual case of TM in a middle-aged adult immunocompetent patient that developed concomitant to an active VZV infection. The 46-year-old male presented with painful vesicular eruption on his left chest that had steadily progressed to involvement of his back over a 3-d period. Cerebrospinal fluid testing was denied, but findings from magnetic resonance imaging and collective symptomology indicated TM. He was administered antiviral drugs and corticosteroids immediately but his symptom improvement waxed and waned, necessitating multiple hospital admissions. After about a month of repeated treatments, he was deemed sufficiently improved for hospital discharge to home.

CONCLUSION

VZV myelitis should be suspected when a patient visits the outpatient pain clinic with herpes zoster showing neurological symptoms.

Abnormal within- and cross-networks functional connectivity in different outcomes of herpes zoster patients

Neuroimaging studies have displayed aberrant brain activities in individual sensory- and emotional-linked regions in postherpetic neuralgia (PHN) patients. However, multi-dimensional dysfunction in chronic pain may rely on the interplay between networks. Little is known about the changes in the functional architecture of resting state networks (RSNs) in PHN. In this cross-sectional study, we recruited 31 PHN patients, 33 RHZ patients and 34 HCs; all participants underwent resting-state functional magnetic resonance imaging scans. We investigated the differences of within- and cross-network connectivities between different outcomes of HZ patients [including PHN and recuperation from herpes zoster (RHZ)] and healthy controls (HCs) so as to extract a characteristic network pattern of PHN. The abnormal network connectivities were then correlated with clinical variables in respective groups. PHN and RHZ patients could be similarly characterized by abnormal within-default mode network (DMN), DMN-salience network (SN) and SN-basal ganglia network (BGN) connectivity relative to HCs. Of note, compared with RHZ patients, PHN patients could be characterized by abnormal DMN-BGN and within-BGN connectivity. Furthermore, the within-DMN connectivity was associated with pain-induced emotional scores among PHN patients. Our study presented that network-level imbalance could account for the pain-related dysfunctions in different outcomes of herpes zoster patients. These insights are potentially useful for understanding neuromechanism of PHN and providing central therapeutic targets for PHN.

C-tactile touch perception in patients with chronic pain disorders

Supplemental Digital Content is Available in the Text. C-tactile stimulation in patients with chronic pain results in reduced pleasantness perception. Results suggest impaired C-tactile function with functional loss of pleasant touch perception in patients with postherpetic neuralgia.

Introduction:

Slow brushing over the skin activates C-tactile nerve fibers that transmit pleasant tactile experiences in healthy subjects, leading to an inverted U-shaped velocity dependence of ratings: C-tactile optimal stroking stimulations are rated as more pleasant than slower or faster stimulations. Chronic pain diseases such as postherpetic neuralgia (PHN) and complex regional pain syndrome show altered C-fiber innervation density, sensory loss, and pain sensitization.

Objectives:

We aimed to investigate whether C-tactile function is affected in painful conditions.

Methods:

We assessed psychophysically C-tactile function and sensory perception thresholds in 16 patients with PHN, 19 patients with complex regional pain syndrome, and 22 healthy controls.

Results:

Assessment of C-tactile function showed a significantly altered perceived pleasantness of CT stimulation between healthy controls and patients with chronic pain. In specific, tactile stimulation was perceived less pleasant on the affected and contralateral side when compared with controls. In patients with PHN, velocity-dependent pleasantness ratings could not be obtained, suggesting highly impaired C-tactile function with functional loss of pleasant touch perception.

Conclusions:

In conclusion, this is the first report of impaired C-tactile function in patients with PHN. Reduced pleasantness resulting from gentle touch can reflect defective C-fiber function or result from central nervous system effects in a chronic pain state.

Efficacy and safety of pulsed radiofrequency modulation of thoracic dorsal root ganglion or intercostal nerve on postherpetic neuralgia in aged patients: a retrospective study

BACKGROUND

Postherpetic neuralgia (PHN) is common in elderly patients and can be alleviated by pulsed radiofrequency (PRF). However, PRF treatments display different efficacy on different nerves. The purpose of this study was to evaluate the efficacy and safety of ultrasound-guided PRF modulation on thoracic dorsal root ganglion (DRG) or intercostal nerve (ICN) for PHN in aged patients and to provide a theoretical basis for clinical treatment.

METHODS

We classified aged patients into two groups, DRG group and ICN group, based on the needle tip position. Visual analogue scale (VAS) and concise health status questionnaire (Short-form 36 health/survey questionnaire, SF-36) were used to evaluate the pain intensity and the life quality of the patients before and 2, 4 and 12 weeks after the PRF treatments. We also recorded the adverse reactions during the treatments.

RESULTS

After the PRF treatment, the scores of VAS and SF-36 (assessing general health perception, social function, emotional role, mental health, and pain) improved significantly in both groups (P < 0.05). The mean VAS score in the DRG group was significantly lower than that in the ICN group 2 weeks after treatment, and remained for 12 weeks. The SF-36 scores in the DRG group were significantly higher than those in the ICN group (P < 0.05). We found a similar incidence of adverse reactions between the two groups (P > 0.05).

CONCLUSIONS

PRF therapy is safe and effective for elderly patients with postherpetic neuralgia. However, PRF treatment in dorsal root ganglion is superior to that in intercostal nerve with improving VAS and SF-36 scores to a greater extent in older patients.

TRIAL REGISTRATION

ChiCTR2100044176 .

Economic Burden and Impact on Quality of Life of Herpes Zoster in Spanish Adults Aged 50 Years or Older: A Prospective Cohort Study

Introduction

The economic burden of herpes zoster (HZ), including its most common complication, postherpetic neuralgia (PHN), and its impact on health-related quality of life (HRQL) is not well described in Spain. The aim of this study was to estimate HZ-related healthcare costs and impact on HRQL in Spanish adults aged 50 years or older.

Methods

A prospective, observational study was performed with patients with HZ recruited through four general practitioner networks in Spain (NCT01521286). HRQL data were collected using the EuroQoL-5 Dimension (EQ-5D) questionnaire; HZ-related pain and associated interference with activities of daily living (ADL) were assessed using the Zoster Brief Pain Inventory (ZBPI) questionnaire at days 0 (HZ rash onset), 15, 30, 60, and 90; patients with PHN were assessed up until day 270. Medical resource utilization was recorded throughout study follow-up. Work loss for patients/caregivers was also assessed. Costs were calculated from both the payer and societal perspectives.

Results

A total of 545 patients with Hz were included, of whom 25 developed PHN. During days 0–30 post HZ diagnosis, the mean EQ-5D utility score was 0.738, equating to a utility loss of 0.138. Sleep was the ADL most affected component. The mean costs for HZ in the overall cohort were €240 and €296 from the payer/societal perspective, respectively; €187/€242 for patients with HZ without any HZ-related complications; and €571/€712 for patients who developed PHN. The majority of costs were incurred during days 0–30.

Conclusions

In Spain, HZ and HZ-related complications such as PHN reduce patient HRQL and increase the economic burden for both payers and society in general.

Trail Registration

ClinicalTrials.gov identifier NCT01521286.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01717-7.

P2X7 receptor antagonist BBG inhibits endoplasmic reticulum stress and pyroptosis to alleviate postherpetic neuralgia

Postherpetic neuralgia (PHN) is the most common complication of acute herpes zoster. The treatment of PHN remains a challenge for clinical pain management. The present study investigated the P2X7 receptor antagonist brilliant blue G (BBG) whether inhibits endoplasmic reticulum stress and pyroptosis (a necrotic form of cell death) and alleviates PHN. Varicella zoster virus (VZV)-infected CV-1 cells were used to induce PHN model. Mechanical paw withdrawal thresholds were measured using an ascending series of von Frey filaments. Immunohistochemistry was used to detect the expression of P2X7R in nerve tissues. Western blot was used to determine the expression of endoplasmic reticulum (ER) stress and pyroptosis-related molecules. The expression of IL-1β and IL-18 in tissue homogenate was detected by ELISA. The PHN rat has the lower paw withdrawal threshold, but higher expression of P2X7 in nerve tissues. And, endoplasmic reticulum stress was activated and pyroptosis was increased in PHN rats. BBG can decrease pain thresholds and reduce ER stress and pyroptosis in PHN rats. In addition, ER stress activator tunicamycin (TM) can reverse the effect of BBG on the paw withdrawal thresholds, endoplasmic reticulum stress, and pyroptosis. Therefore, P2X7 receptor antagonist BBG alleviates PHN by activating ER stress and reducing pyroptosis.

Inhibiting BDNF/TrkB.T1 receptor improves resiniferatoxin-induced postherpetic neuralgia through decreasing ASIC3 signaling in dorsal root ganglia

BACKGROUND

Postherpetic neuralgia (PHN) is a devastating complication after varicella-zoster virus infection. Brain-derived neurotrophic factor (BDNF) has been shown to participate in the pathogenesis of PHN. A truncated isoform of the tropomyosin receptor kinase B (TrkB) receptor TrkB.T1, as a high-affinity receptor of BDNF, is upregulated in multiple nervous system injuries, and such upregulation is associated with pain. Acid-sensitive ion channel 3 (ASIC3) is involved in chronic neuropathic pain, but its relation with BDNF/TrkB.T1 in the peripheral nervous system (PNS) during PHN is unclear. This study aimed to investigate whether BDNF/TrkB.T1 contributes to PHN through regulating ASIC3 signaling in dorsal root ganglia (DRGs).

METHODS

Resiniferatoxin (RTX) was used to induce rat PHN models. Mechanical allodynia was assessed by measuring the paw withdrawal thresholds (PWTs). Thermal hyperalgesia was determined by detecting the paw withdrawal latencies (PWLs). We evaluated the effects of TrkB.T1-ASIC3 signaling inhibition on the behavior, neuronal excitability, and inflammatory response during RTX-induced PHN. ASIC3 short hairpin RNA (shRNA) transfection was used to investigate the effect of exogenous BDNF on inflammatory response in cultured PC-12 cells.

RESULTS

RTX injection induced mechanical allodynia and upregulated the protein expression of BDNF, TrkB.T1, ASIC3, TRAF6, nNOS, and c-Fos, as well as increased neuronal excitability in DRGs. Inhibition of ASIC3 reversed the abovementioned effects of RTX, except for BDNF and TrkB.T1 protein expression. In addition, inhibition of TrkB.T1 blocked RTX-induced mechanical allodynia, activation of ASIC3 signaling, and hyperexcitability of neurons. RTX-induced BDNF upregulation was found in both neurons and satellite glia cells in DRGs. Furthermore, exogenous BDNF activated ASIC3 signaling, increased NO level, and enhanced IL-6, IL-1β, and TNF-α levels in PC-12 cells, which was blocked by shRNA-ASIC3 transfection.

CONCLUSION

These findings demonstrate that inhibiting BDNF/TrkB.T1 reduced inflammation, decreased neuronal hyperexcitability, and improved mechanical allodynia through regulating the ASIC3 signaling pathway in DRGs, which may provide a novel therapeutic target for patients with PHN.