Evidence-Based Case Report: The Prevention and Management of Postherpetic Neuralgia With Emphasis on Interventional Procedures

Comparison of Adjuvant Hypertonic Saline and Normal Saline for Epidural Block in Patients with Postherpetic Neuralgia: A Double-Blind, Randomized Trial

Background

In patients with postherpetic neuralgia (PHN), the effectiveness of epidural block and the benefits of adjuvant hypertonic saline (HS) have not been fully determined. Therefore, we investigated these issues in this study.

Methods

At a tertiary medical center's single pain clinic in Seoul, Republic of Korea, patients complaining of PHN even after 4 months of herpes zoster onset were enrolled and randomly assigned to either the HS or normal saline (NS) group. After epidural block with adjuvant HS or NS administration according to each protocol, outcomes were assessed at baseline and one and three months after the intervention. The primary outcome was pain intensity on the numerical rating scale (NRS). The secondary outcomes were the insomnia severity index (ISI), the medication quantification scale (MQS), and the global perceived effect of satisfaction (GPES).

Results

Thirty-six patients (NS: 17, HS: 19) were included in the intention-to-treat analysis. The estimated pain intensity decreased in both groups at one and three months after the procedure (P < 0.001), without a significant group difference. The estimated ISI and MQS were not significantly different at 1 month compared with baseline but significantly decreased at 3 months in each group (P < 0.001 and P < 0.001, respectively), without group differences. In addition, there was no difference between the groups on the GPES scale at one and three months after the procedure.

Conclusions

Epidural steroid injection may have the advantages of short-term pain relief, improved sleep quality, and decreased medication usage in patients with PHN. In addition, adjuvant HS administration with epidural steroid injection did not show beneficial effects in patients with PHN. Further studies are needed to clarify the potential effectiveness of HS in treating neuropathic pain such as PHN. This trial is registered with KCT0002845.

Computed Tomography-Guided Radiofrequency Ablation of the Cervical Dorsal Root Ganglia in 27 Patients with Cervical and Occipital Postherpetic Neuralgia

Background

Postherpetic neuralgia (PHN) is a common complication of herpes zoster virus infection that is associated with intense pain. The present study aimed to investigate the use of computed tomography (CT)-guided radiofrequency ablation (RFA) of the cervical dorsal root ganglia (DRG) for treatment of cervical and occipital PHN in 27 patients at a single center.

Material/Methods

Twenty-seven patients with PHN in the cervical and/or occipital region were enrolled. After imaging the area of PHN in the patients, axial scanning was performed on the upper cervical segment in the spinal scanning mode. The puncture path was defined and then RFA therapy (90°C for 180 s) was performed by targeting the corresponding intervertebral foramen. Patients were followed 2 days later and at 1, 3, 6, and 12 months after surgery. Observation at each follow-up visit included rating of pain on a visual analog scale (VAS) and assessment of complications and adverse events.

Results

VAS scores significantly decreased in patients with PHN after RFA compared with their scores before RFA (P<0.05). Skin sensation decreased in the area that was originally painful and allodynia significantly diminished.

Conclusions

The findings from this small study from a single center showed that CT-guided percutaneous RFA of cervical DRG safely and effectively reduced cervical and occipital PHN in the short term.

Ultrasound-guided Erector Spinae Plane Block for the Management of Herpes Zoster Pain: Observational Study

Background

Herpes zoster is caused by the reactivation of latent varicella-zoster virus, which promotes acute and chronic pain that may interfere with daily activities and reduce the quality of life. Ultrasound-guided erector spinae plane (ESP) blocks are used for a wide variety of indications in the management of acute, chronic, and postoperative pain. Our aim was to evaluate the efficacy of ultrasound-guided erector spinae plane blocks for the management of pain in herpes zoster.

Methods

The medical records of 34 patients with acute or chronic pain during herpes zoster between May 2017 and June 2018 were investigated at two pain clinic centers. The patients received ultrasound-guided erector spinae plane block: We performed a single injection for the patients having acute pain and a continuous block for the patients having chronic pain. Patient characteristics, block characteristics (needle insertion level, catheter, or single insertion), the volume of given local anesthetics, the intensity of pain before and after the block procedure using a numerical rating score (NRS) between 0 and 10, and the duration of analgesia were evaluated.

Results

All patients reported a remarkable and rapid resolution of pain immediately after the block procedure. Median (min-max) NRS score before the block procedure was 9 (4-10). The median (min-max) NRS score was 1.5 (0-7) after the block procedure. The difference was found to be statistically significant (p<0.0001). NRS score after the third month was 1 (0-3); the difference is statistically significant (p=0.002). The median value of analgesia time (min-max) was 18 (3-24) hours.

Conclusion

Our preliminary experience demonstrated that an ESP block provided sufficient analgesia in acute herpetic pain. A combination of ESP block, pregabalin, and tramadol was also effective within the three-months-period after the block performance.

Interventional pain management for spinal disorders: a review of injection techniques

Chronic spinal pain has a high prevalence and a severe economic, societal and health impact. In the last decades the practice and research of interventional techniques for the diagnosis and treatment of spinal pain has increased sharply. The level of evidence of the most common techniques is well documented. With image-guided precise diagnostic blocks it is possible to identify the source of chronic spinal pain in well over 60% of the cases. Nonsurgical specialties such as PM&R increasingly resort to the possibilities of interventional pain management for musculoskeletal disorders. For many forms of spinal pain there is at least fair evidence for long-term pain relief after a guided therapeutic injection often reducing the intake of analgesic medication or the need for surgery. This review focuses on the evidence, the application spectrum and special considerations of injection techniques for the treatment of spinal disorders.

The appropriate use of neurostimulation of the spinal cord and peripheral nervous system for the treatment of chronic pain and ischemic diseases: the Neuromodulation Appropriateness Consensus Committee

INTRODUCTION

The Neuromodulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society (INS) evaluated evidence regarding the safety and efficacy of neurostimulation to treat chronic pain, chronic critical limb ischemia, and refractory angina and recommended appropriate clinical applications.

METHODS

The NACC used literature reviews, expert opinion, clinical experience, and individual research. Authors consulted the Practice Parameters for the Use of Spinal Cord Stimulation in the Treatment of Neuropathic Pain (2006), systematic reviews (1984 to 2013), and prospective and randomized controlled trials (2005 to 2013) identified through PubMed, EMBASE, and Google Scholar.

RESULTS

Neurostimulation is relatively safe because of its minimally invasive and reversible characteristics. Comparison with medical management is difficult, as patients considered for neurostimulation have failed conservative management. Unlike alternative therapies, neurostimulation is not associated with medication-related side effects and has enduring effect. Device-related complications are not uncommon; however, the incidence is becoming less frequent as technology progresses and surgical skills improve. Randomized controlled studies support the efficacy of spinal cord stimulation in treating failed back surgery syndrome and complex regional pain syndrome. Similar studies of neurostimulation for peripheral neuropathic pain, postamputation pain, postherpetic neuralgia, and other causes of nerve injury are needed. International guidelines recommend spinal cord stimulation to treat refractory angina; other indications, such as congestive heart failure, are being investigated.

CONCLUSIONS

Appropriate neurostimulation is safe and effective in some chronic pain conditions. Technological refinements and clinical evidence will continue to expand its use. The NACC seeks to facilitate the efficacy and safety of neurostimulation.

The effects of glucocorticoids on neuropathic pain: a review with emphasis on intrathecal methylprednisolone acetate delivery

Methylprednisolone acetate (MPA) has a long history of use in the treatment of sciatic pain and other neuropathic pain syndromes. In several of these syndromes, MPA is administered in the epidural space. On a limited basis, MPA has also been injected intrathecally in patients suffering from postherpetic neuralgia and complex regional pain syndrome. The reports on efficacy of intrathecal administration of MPA in neuropathic pain patients are contradictory, and safety is debated. In this review, we broadly consider mechanisms whereby glucocorticoids exert their action on spinal cascades relevant to the pain arising after nerve injury and inflammation. We then focus on the characteristics of the actions of MPA in pharmacokinetics, efficacy, and safety when administered in the intrathecal space.

Vaccination against and treatment of acute herpes zoster for prevention of post-herpetic neuralgia

Zostavax (zoster vaccine) is a 1-dose, high-potency, live, attenuated varicella zoster virus (VZV) vaccine that boosts VZV-specific cell-mediated immunity (CMI), and this is its presumed mechanism of action. Other strategies focus on preventing the major complication of HZ, post-herpetic neuralgia (PHN). Evidence that the vaccine is effective in older patients comes from the pivotal Shingles Prevention Study. That study demonstrated that HZ vaccine significantly reduced morbidity due to HZ and PHN in older patients. However, the duration of efficacy beyond 5 years after vaccination remains unclear. The Long-Term Persistence Substudy, currently under analysis, may provide additional data on the duration of efficacy for zoster vaccine. This review discusses vaccination against HZ, and further reviews recent pharmacotherapy for prevention of PHN.

Epidural steroids: a comprehensive, evidence-based review

Epidural steroid injections (ESIs) are the most widely utilized pain management procedure in the world, their use supported by more than 45 placebo-controlled studies and dozens of systematic reviews. Despite the extensive literature on the subject, there continues to be considerable controversy surrounding their safety and efficacy. The results of clinical trials and review articles are heavily influenced by specialty, with those done by interventional pain physicians more likely to yield positive findings. Overall, more than half of controlled studies have demonstrated positive findings, suggesting a modest effect size lasting less than 3 months in well-selected individuals. Transforaminal injections are more likely to yield positive results than interlaminar or caudal injections, and subgroup analyses indicate a slightly greater likelihood for a positive response for lumbar herniated disk, compared with spinal stenosis or axial spinal pain. Other factors that may increase the likelihood of a positive outcome in clinical trials include the use of a nonepidural (eg, intramuscular) control group, higher volumes in the treatment group, and the use of depo-steroid. Serious complications are rare following ESIs, provided proper precautions are taken. Although there are no clinical trials comparing different numbers of injections, guidelines suggest that the number of injections should be tailored to individual response, rather than a set series. Most subgroup analyses of controlled studies show no difference in surgical rates between ESI and control patients; however, randomized studies conducted by spine surgeons, in surgically amenable patients with standardized operative criteria, indicate that in some patients the strategic use of ESI may prevent surgery.

Peripheral nerve surgery for the treatment of postherpetic neuralgia

Postherpetic neuralgia is a chronic pain condition that develops in some patients after the resolution of herpes zoster, and has no medical cure. Medications used to treat chronic pain do not hasten resolution of the disorder and may impair function. In this brief case report, we describe our experience with excision and implantation to muscle of peripheral sensory nerves in the affected dermatomes as a novel surgical treatment to reduce pain and improve quality of life for patients with this condition. Of the 3 treated patients, all had resolution of chronic pain after surgery. It is concluded that peripheral nerve surgery offers a promising option to improve pain and quality of life in postherpetic neuralgia patients, without affecting systemic functioning.

Spinal cord stimulation in the treatment of postherpetic neuralgia in patients with chronic kidney disease: a case series and review of the literature

BACKGROUND

Postherpetic neuralgia (PHN) is usually managed pharmacologically. It is not uncommon for patients with chronic kidney disease (CKD) to suffer from PHN. It is difficult to prescribe a sufficient dose of anticonvulsants for intractable pain because of the decreased glomerular filtration rate. If the neural blockade and pulsed radiofrequency ablation provide only short-term amelioration of pain, spinal cord stimulation (SCS) with a low level of evidence may be used only as a last resort. This study was done to evaluate the efficacy of spinal cord stimulation in the treatment of PHN in patients with CKD.

METHODS

PHN patients with CKD who needed hemo-dialysis who received insufficient relief of pain over a VAS of 8 regardless of the neuropathic medications were eligible for SCS trial. The follow-up period was at least 2 years after permanent implantation.

RESULTS

Eleven patients received percutaneous SCS test trial from Jan 2003 to Dec 2007. Four patients had successfully received a permanent SCS implant with their pain being tolerable at a VAS score of less than 3 along with small doses of neuropathic medications.

CONCLUSIONS

SCS was helpful in managing tolerable pain levels in some PHN patients with CKD along with tolerable neuropathic medications for over 2 years.