Optimum pain relief with continuous epidural infusion of local anesthetics shortens the duration of zoster-associated pain

Lumbar sympathetic pulsed radiofrequency combined with continuous epidural infusion for treatment of painful diabetic neuropathy: A report of two cases and a literature review

Diabetic neuropathy (DN), one of the most common late complications of diabetes mellitus, significantly affects distinct regions of the nervous system. Pain management is challenging in DN as no effective therapies exist that reverse the pathological course of DN. Several drugs are recommended as the first-line treatment for painful DN, but these are associated with various side-effects in the long term. This report presents two cases with painful DN who underwent lumbar sympathetic pulsed radiofrequency combined with continuous epidural infusion. The two cases were followed for 30 days. Lumbar sympathetic pulsed radiofrequency combined with continuous epidural infusion offered effective pain relief and improved the health-related quality of life in two patients with DN over this time period.

Pharmacological and non-pharmacological strategies for preventing postherpetic neuralgia: a systematic review and network meta-analysis

Background

Postherpetic neuralgia (PHN) is a refractory complication of herpes zoster (HZ). To prevent PHN, various strategies have been aggressively adopted. However, the efficacy of these strategies remains controversial. Therefore, we aimed to estimate the relative efficacy of various strategies used in clinical practice for preventing PHN using a network meta-analysis (NMA).

Methods

We performed a systematic and comprehensive search to identify all randomized controlled trials. The primary outcome was the incidence of PHN at 3 months after acute HZ. We performed both frequentist and Bayesian NMA and used the surface under the cumulative ranking curve (SUCRA) values to rank the interventions evaluated.

Results

In total, 39 studies were included in the systematic review and NMA. According to the SUCRA value, the incidence of PHN was lower in the order of continuous epidural block with local anesthetics and steroids (EPI-LSE), antiviral agents with subcutaneous injection of local anesthetics and steroids (AV + sLS), antiviral agents with intracutaenous injection of local anesthetics and steroids (AV + iLS) at 3 months after acute HZ. EPI-LSE, AV + sLS and AV + iLS were also effective in preventing PHN at 1 month after acute HZ. And paravertebral block combined with antiviral and antiepileptic agents was effective in preventing PHN at 1, 3, and 6 months.

Conclusions

The continuous epidural block with local anesthetics and steroid, antiviral agents with intracutaneous or subcutaneous injection of local anesthetics and a steroid, and paravertebral block combined with antiviral and antiepileptic agents are effective in preventing PHN.

Efficacy of continuous epidural infusion with epidural electric stimulation compared to that of conventional continuous epidural infusion for acute herpes zoster management: a retrospective study

Background

Continuous epidural infusions are commonly used in clinical settings to reduce the likelihood of transition to postherpetic neuralgia via pain control. The purpose of this study was to compare the efficacy of conventional continuous epidural infusion to that of continuous epidural infusion in which the catheter is guided by electric stimulation to areas with neurological damage for the treatment of zoster-related pain and prevention of postherpetic neuralgia.

Methods

We analyzed the medical records of 114 patients in this study. The patients were divided into two groups: contrast (conventional continuous epidural infusion) and stimulation (continuous epidural infusion with epidural electric stimulation). In the contrast group, the position of the epidural catheter was confirmed using contrast medium alone, whereas in the stimulation group, the site of herpes zoster infection was identified through electric stimulation using a guidewire in the catheter. Clinical efficacy was assessed using a numerical rating scale (pain score) up to 6 months after the procedures. We compared the percentage of patients who showed complete remission (pain score less than 2 and no further medication) in each group. We also investigated whether the patients required additional interventional treatment due to insufficient pain control during the 6-month follow-up period after each procedure.

Results

After adjusting for confounding variables, the pain score was significantly lower in the stimulation group than in the contrast group for 6 months after the procedure. After adjustment, the odds of complete remission were 1.9-times higher in the stimulation group than in the contrast group (95% confidence interval [CI]: 0.81–4.44, P = 0.14). Patients in the contrast group were significantly more likely to require other interventions within 6 months of the procedure than patients in the stimulation group (odds ratio: 3.62, 95% CI: 1.17–11.19, P = 0.03).

Conclusion

Epidural drug administration to specific spinal segments using electric stimulation catheters may be more helpful than conventional continuous epidural infusion for improving pain and preventing postherpetic neuralgia in the acute phase of herpes zoster.

Comparison of therapeutic effects of continuous epidural nerve block combined with drugs on postherpetic neuralgia

PURPOSE

To compare the therapeutic effects of continuous epidural block combined with drugs and oral drugs alone on postherpetic neuralgia (PHN).

METHODS

Ninety-six PHN patients meeting the standard were selected and divided into group A and group B. Patients in group A had epidural block combined with oral administration of gabapentin and oxycodone-acetaminophen, and patients in group B received oral gabapentin and oxycodone-acetaminophen. Visual analogue scale (VAS) and Wisconsin brief pain inventory scores were used to evaluate the patients in group A and group B for 6 times (before treatment, 1 d, 3 d, 7 d, 15 d and 30 d after treatment) respectively, and the complications and adverse reactions of the two treatment methods, as well as the number of cases requiring remedial measures were observed.

RESULTS

There were significant differences in VAS and Wisconsin brief pain inventory scores at 1 d, 3 d, 7 d, 15 d and 30 d after treatment between the two groups (p < 0.05). Moreover, the scores before and after treatment decreased with the time of treatment, and there was a significant difference between the two groups at different time points (p < 0.05). No significant adverse reactions were observed in group A except for 1 patient with catheter detachment. Compared with group A, the adverse reactions of group B were more varied and obvious.

CONCLUSION

Both treatments have certain effects on PHN, but epidural block combined with drug therapy is more effective, especially for patients with severe pain, early use can quickly relieve pain.

Efficacy of intermittent epidural dexamethasone bolus for zoster-associated pain beyond the acute phase

Herpes zoster develops when latent varicella zoster virus is reactivated in the trigeminal or dorsal root ganglions. Zoster-associated pain (ZAP) is neuropathic pain caused by the herpes zoster virus. Histological studies of postherpetic neuralgia patients suggest that inflammation is involved in ZAP. The effectiveness of local anesthetic and steroid epidural injections in ZAP patients has been reported. However, most studies included patients with acute herpes zoster, and the safety and therapeutic effects of different doses of epidural steroids in ZAP patients remain elusive. In this study, we randomly assigned 42 patients with severe ZAP beyond the acute phase, as determined by a numeric rating scale (NRS) score ≥7, to receive continuous epidural infusion of local anesthetics with either a one-time 5-mg dose or intermittent repeated doses (15 mg total) of dexamethasone. We found that intermittent repeated epidural dexamethasone bolus resulted in reduced NRS scores and an increased likelihood of complete remission in ZAP patients without any adverse effects. Thus, our results suggest that intermittent repeated epidural dexamethasone administration is safe and effective for treatment of ZAP beyond the acute phase.

Comparison of the efficacy of continuous epidural block with epidural electrical stimulation and conventional continuous epidural block for management of zoster-associated pain beyond the acute phase: A retrospective study

Continuous epidural block (CEB) is a popular clinical method for controlling postherpetic neuralgia (PHN). However, the long-term effects of CEB on PHN have not yet been established. This study aimed to confirm the clinical efficacy of epidural electrical stimulation catheters in CEB to manage PHN.Patients were classified into 2 groups: those with subacute PHN, between 30 and 180 days after the onset of the rash; and those with chronic PHN, over 180 days after the onset of the rash. On the basis of the type of catheter used, the patients were further divided into the following 2 groups: the esopocan group, in which the site of herpes zoster infection was confirmed using a contrast medium alone; and the epistim group, in which an additional method of electrical stimulation through a guide-wire in the catheter was used for detecting the site affected by herpes. Clinical efficacy was assessed with a numerical rating scale immediately 1, 3, and 6 months after the procedure. We also investigated whether additional interventional treatment was necessitated because of insufficient pain control during the 6-month follow-up.We examined 88 patients. In the subacute PHN period, the numerical rating scale score was significantly lower in the epistim group than in the esopocan group until 6 months. In the chronic PHN period, no significant differences in the numerical rating scale scores were observed between the 2 groups until 6 months. In the subacute PHN period, the adjusted odds ratio for other interventional procedures within 6 months in the esopocan group versus the epistim group was 2.59 (95% confidence interval [CI] 0.83-8.09, P = .10), and in the chronic PHN period, it was 1.31 (95% CI 0.11-5.46, P = .79).Epidural drug administration to specific segments using electrical stimulation catheters may be more useful in mitigating zoster-associated pain in subacute PHN.

Comparison of efficacy of continuous epidural block and pulsed radiofrequency to the dorsal root ganglion for management of pain persisting beyond the acute phase of herpes zoster

Background

There is little evidence regarding the effectiveness of intervention methods in the treatment of zoster-related pain (ZAP) after the acute phase of zoster. Generally, if ZAP remains after more than 180 days from its onset, the likelihood of pain reduction is very low; this condition is considered as a “well established” post-herpetic neuralgia (PHN). Although the clinical efficacy of intrathecal steroid injection and spinal cord stimulation (SCS) for ZAP management has been reported, these interventions are not widely used due to inherent disadvantages. Continuous epidural block is widely used in clinical practice, and the effectiveness of pulsed radiofrequency (PRF) to the dorsal root ganglion (DRG) in the treatment of ZAP already has been reported.

Objectives

The purpose of this study was to compare the clinical efficacy of continuous epidural block and DRG PRF beyond acute phase of zoster, bur before PHN was well established (from 30 days to180 days after zoster onset).

Study design

Retrospective comparative study.

Methods

A total of 42 medical records were analyzed. Patients were divided into two groups according to the type of procedure utilized: continuous epidural block (continuous epidural group) and DRG PRF (PRF group). The clinical efficacy of the procedure was evaluated using a numeric rating scale (NRS) and the medication dose before and 1 to 6 months after the procedure.

Results

There was a significant decrease in the NRS value with time in both groups. However, this decrease was more significant in the PRF group than in the continuous epidural group. The medication doses decreased significantly in the PRF group over time, but not in the continuous epidural group. The rate of clinically meaningful PHN (NRS≥3) was also lower in the PRF group than in the continuous epidural group.

Conclusions

This study revealed that DRG PRF was more effective than a continuous epidural block in treating ZAP after the acute phase of zoster. A neuromodulation method such as DRG PRF may be a useful option for reducing the progression of neuropathic changes caused by the persistent transmission of a pain signal after the acute phase of zoster.

Looking back to move forward: a twenty-year audit of herpes zoster in Asia-Pacific

Background

Herpes zoster (HZ) is a prevalent viral disease that inflicts substantial morbidity and associated healthcare and socioeconomic burdens. Current treatments are not fully effective, especially among the most vulnerable patients. Although widely recommended, vaccination against HZ is not routine; barriers in Asia-Pacific include long-standing neglect of adult immunisation and sparse local data. To address knowledge gaps, raise awareness, and disseminate best practice, we reviewed recent data and guidelines on HZ from the Asia-Pacific region.

Methods

We searched PubMed, Scopus, and World Health Organization databases for articles about HZ published from 1994 to 2014 by authors from Australia, China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, New Zealand, the Philippines, Singapore, Taiwan, Thailand, and Vietnam. We selected articles about epidemiology, burden, complications, comorbidities, management, prevention, and recommendations/guidelines. Internet searches retrieved additional HZ immunisation guidelines.

Results

From 4007 retrieved articles, we screened-out 1501 duplicates and excluded 1264 extraneous articles, leaving 1242 unique articles. We found guidelines on adult immunisation from Australia, India, Indonesia, Malaysia, New Zealand, the Philippines, South Korea, and Thailand.

HZ epidemiology in Asia-Pacific is similar to elsewhere; incidence rises with age and peaks at around 70 years – lifetime risk is approximately one-third. Average incidence of 3–10/1000 person-years is rising at around 5% per year. The principal risk factors are immunosenescence and immunosuppression. HZ almost always causes pain, and post-herpetic neuralgia is its most common complication. Half or more of hospitalised HZ patients have post-herpetic neuralgia, secondary infections, or inflammatory sequelae that are occasionally fatal. These disease burdens severely diminish patients’ quality of life and incur heavy healthcare utilisation.

Conclusions

Several countries have abundant data on HZ, but others, especially in South-East Asia, very few. However, Asia-Pacific countries generally lack data on HZ vaccine safety, efficacy and cost-effectiveness. Physicians treating HZ and its complications in Asia-Pacific face familiar challenges but, with a vast aged population, Asia bears a unique and growing burden of disease. Given the strong rationale for prevention, most adult immunisation guidelines include HZ vaccine, yet it remains underused. We urge all stakeholders to give higher priority to adult immunisation in general and HZ in particular.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2198-y) contains supplementary material, which is available to authorized users.

Effects of applying nerve blocks to prevent postherpetic neuralgia in patients with acute herpes zoster: a systematic review and meta-analysis

BACKGROUND

Postherpetic neuralgia (PHN) is a common and painful complication of acute herpes zoster. In some cases, it is refractory to medical treatment. Preventing its occurrence is an important issue. We hypothesized that applying nerve blocks during the acute phase of herpes zoster could reduce PHN incidence by attenuating central sensitization and minimizing nerve damage and the anti-inflammatory effects of local anesthetics and steroids.

METHODS

This systematic review and meta-analysis evaluates the efficacy of using nerve blocks to prevent PHN. We searched the MEDLINE, EMBASE, Cochrane Library, ClinicalTrials.gov and KoreaMed databases without language restrictions on April, 30 2014. We included all randomized controlled trials performed within 3 weeks after the onset of herpes zoster in order to compare nerve blocks vs active placebo and standard therapy.

RESULTS

Nine trials were included in this systematic review and meta-analysis. Nerve blocks reduced the duration of herpes zoster-related pain and PHN incidence of at 3, 6, and 12 months after final intervention. Stellate ganglion block and single epidural injection did not achieve positive outcomes, but administering paravertebral blockage and continuous/repeated epidural blocks reduced PHN incidence at 3 months. None of the included trials reported clinically meaningful serious adverse events.

CONCLUSIONS

Applying nerve blocks during the acute phase of the herpes zoster shortens the duration of zoster-related pain, and somatic blocks (including paravertebral and repeated/continuous epidural blocks) are recommended to prevent PHN. In future studies, consensus-based PHN definitions, clinical cutoff points that define successful treatment outcomes and standardized outcome-assessment tools will be needed.

Efficacy of continuous epidural block in acute herpes zoster: Incidence and predictive factors of postherpetic neuralgia, a retrospective single-center study

The aim of the present study was to investigate efficacy of continuous epidural block for prevent postherpetic neuralgia (PHN) progression in cases of acute herpes zoster with severe pain and also to identify predictive factors for PHN in such conditions.We retrospectively analyzed the clinical data of patients with herpes zoster who underwent continuous epidural block between March 2013 and October 2015. Time points were set as 1 month, 3 months, and 6 months after zoster onset. PHN was defined as the presence of pain with NRS ≥3 at certain time points.The incidence of developing PHN was 38.1%, 27.0%, and 19.0% 1 month, 3 months, and 6 months after zoster onset, respectively. Age and duration of catheterization were predictive factors for PHN at 1 month. Age, duration of catheterization, and NRS at first visit were identified as predictive factors for PHN at 3 months. Presence of diabetes, duration of catheterization, and NRS during catheterization were significant predictive factors for PHN at 6 months.The incidence of PHN is higher in zoster patients with severe pain that requires continuous epidural block compared to incidence in the general population. Advanced age and severe initial pain intensity were predictive factors of PHN development. Prolonged catheterization resulting from weak response to treatment strongly suggested progression to PHN.

Epidural catheterization with a subcutaneous injection port for the long-term administration of opioids and local anesthetics to treat zoster-associated pain -a report of two cases-

Continuous epidural analgesia has been used for decades to treat acute herpes zoster pain and to prevent postherpetic neuralgia. However, many technical problems can arise during chronic treatment with epidural medications. These complications include catheter dislodgement, infection, injection pain, leakage, and occlusion. Epidural catheter placement utilizing subcutaneous injection port implantation has gained widespread acceptance as a method to overcome such complications. The technique reduces the risk of infection, the most feared complication, compared to the use of a percutaneous epidural catheter. Herein, we present 2 cases in which the continuous thoracic epidural administration of opioids and local anesthetics through an implantable subcutaneous injection port for over 2 months successfully treated zoster-associated pain without any technique- or medication-related complications in patients with risk factors for epidural abscess.

Preventing Chronic Pain following Acute Pain: Risk Factors, Preventive Strategies, and their Efficacy

Chronic pain is the leading cause of disability in the United States. The transition from acute to persistent pain is thought to arise from maladaptive neuroplastic mechanisms involving three intertwined processes, peripheral sensitization, central sensitization, and descending modulation. Strategies aimed at preventing persistent pain may target such processes. Models for studying preventive strategies include persistent post-surgical pain (PPP), persistent post-trauma pain (PTP) and post-herpetic neuralgia (PHN). Such entities allow a more defined acute onset of tissue injury after which study of the long-term effects is more easily examined. In this review, we examine the pathophysiology, epidemiology, risk factors, and treatment strategies for the prevention of chronic pain using these models. Both pharmacological and interventional approaches are described, as well as a discussion of preventive strategies on the horizon.

Management and prevention of herpes zoster: A Canadian perspective

Varicella-zoster virus reactivation leads to herpes zoster - the main complication of which is postherpetic neuralgia (PHN). Rapid antiviral therapy initiated within 72 h of rash onset has been shown to accelerate rash healing, reduce the duration of acute pain and, to some extent, attenuate the development and duration of PHN. Other adjunctive therapies such as analgesics, antidepressants and some anticonvulsants are frequently required in the management of severe PHN. A live, attenuated zoster vaccine has been recently shown to significantly decrease herpes zoster incidence, PHN and the overall burden of illness when administered to adults older than 60 years of age. This new prophylactic modality has been reported to be cost-effective in the Canadian context, especially in the 60- to 75-year-old age group.

The impact of herpes zoster and post-herpetic neuralgia on quality-of-life

BACKGROUND

The potentially serious nature of herpes zoster (HZ) and the long-term complication post-herpetic neuralgia (PHN) are often underestimated. One in four people will contract herpes zoster in their lifetime, with this risk rising markedly after the age of 50 years, and affecting one in two in elderly individuals. Pain is the predominant symptom in all phases of HZ disease, being reported by up to 90% of patients. In the acute phase, pain is usually moderate or severe, with patients ranking HZ pain as more intense than post-surgical or labour pains. Up to 20% of patients with HZ develop PHN, which is moderate-to-severe chronic pain persisting for months or years after the acute phase. We review the available data on the effect of HZ and PHN on patients' quality-of-life.

DISCUSSION

Findings show that HZ, and particularly PHN, have a major impact on patients' lives across all four health domains--physical, psychological, functional and social. There is a clear correlation between increasing severity of pain and greater interference with daily activities. Non-pain complications such as HZ ophthalmicus can increase the risk of permanent physical impairment. Some elderly individuals may experience a permanent loss of independence after an acute episode of HZ. Current challenges in the management of HZ and PHN are highlighted, including the difficulty in administering antiviral agents before pain becomes established and the limited efficacy of pain treatments in many patients. We discuss the clinical rationale for the HZ vaccine and evidence demonstrating that the vaccine reduces the burden of the disease. The Shingles Prevention Study, conducted among >38,000 people aged >or=60 years old, showed that the HZ vaccine significantly reduces the burden of illness and the incidence of both HZ and PHN. In the entire study population, zoster vaccination reduced the severity of interference of HZ and PHN with activities of daily living by two-thirds, as measured by two questionnaires specific to HZ.

SUMMARY

A vaccination scheme may positively impact the incidence and course of HZ disease, thereby improving patients' quality-of-life.

Herpes Zoster and Postherpetic Neuralgia: a review of the effects of vaccination

Herpes zoster (HZ) results from reactivation of varicella zoster virus which has been persistent but clinically latent in dorsal root and cranial nerve ganglia since primary infection, usually as a child, with varicella (chicken pox). HZ affects 20-30% of individuals during their lifetime and up to 50% of those > or =80 years old. Although serious life- or sight-threatening complications occur rarely, postherpetic neuralgia (PHN) is the most common complication. Both HZ and PHN are most common in the elderly. Declining cell-mediated immunity resulting from immune senescence appears to be the cause. Incidence of HZ is also high in individuals who are immunocompromised as a result of disease or its treatment. HZ also occurs in younger and fit individuals but is usually mild and complications are rare. Current management of HZ with antiviral drugs and analgesics attains quite good control of acute pain and skin rash but offers only partial protection against PHN. Other strategies studied to prevent PHN such as nerve blocks are relatively ineffective and clinically impractical. Although several drug classes are used to manage PHN, numbers needed to treat to obtain 50% pain reduction range from approx. 2.5-5 and adverse effects are common. The elderly population is growing and thus the number of HZ and PHN susceptible individuals is increasing. HZ and PHN are expensive in terms of suffering, loss of independence and healthcare costs. Significant numbers of the elderly with HZ require hospitalization. Short-term illness in the elderly can lead to long-term loss of independence. A live attenuated herpes zoster vaccine has been studied in a large number of subjects and shown to reduce incidence of HZ as well as incidence and severity of PHN. The safety profile of the vaccine is good, local soreness at the injection site being the only common adverse event. Health economics studies suggest that vaccination of adults about 60 years of age would be cost effective. Duration of protection following vaccination is the subject of ongoing surveillance, as is the potential benefit of vaccinating younger and sicker members of the population.

Factors contributing to pain chronicity

The chronicity of pain is the feature of pain that is least understood and most directly linked with our inability to effectively manage pain. Acute pain is relatively responsive to our current pharmacologic and interventional armamentarium. However, as pain persists, our ability to treat effectively diminishes and the patient's frustration and resource utilization increases. This article explores our current understanding of the factors linked to pain duration and the transition from acute to chronic pain in both human and animal models, and across a spectrum of human chronic pain conditions.

Recommendations for the management of herpes zoster

The objective of this article is to provide evidence-based recommendations for the management of patients with herpes zoster (HZ) that take into account clinical efficacy, adverse effects, impact on quality of life, and costs of treatment. Systematic literature reviews, published randomized clinical trials, existing guidelines, and the authors' clinical and research experience relevant to the management of patients with HZ were reviewed at a consensus meeting. The results of controlled trials and the clinical experience of the authors support the use of acyclovir, brivudin (where available), famciclovir, and valacyclovir as first-line antiviral therapy for the treatment of patients with HZ. Specific recommendations for the use of these medications are provided. In addition, suggestions are made for treatments that, when used in combination with antiviral therapy, may further reduce pain and other complications of HZ.