Evidence-based guideline for neuropathic pain interventional treatments: spinal cord stimulation, intravenous infusions, epidural injections and nerve blocks

A single infusion of intravenous lidocaine for primary headaches and trigeminal neuralgia: a retrospective analysis

Introduction

Intravenous (IV) lidocaine has been used as a transitional treatment in headache and facial pain conditions, typically as an inpatient infusion over several days, which is costly and may increase the risk of adverse effects. Here we report on our experience using a single one-hour IV lidocaine infusion in an outpatient day-case setting for the management of refractory primary headache disorders with facial pain and trigeminal neuralgia.

Methods

This is a retrospective, single-center analysis on patients with medically refractory headache with facial pain and trigeminal neuralgia who were treated with IV lidocaine between March 2018 and July 2022. Lidocaine 5 mg.kg-1 in 60 mL saline was administered over 1 h, followed by an observation period of 30 min. Patients were considered responders if they reported reduction in pain intensity and/or headache frequency of 50% or greater. Duration of response was defined as short-term (< 2 weeks), medium-term (2-4 weeks) and long-term (> 4 weeks).

Results

Forty infusions were administered to 15 patients with trigeminal autonomic cephalalgias (n = 9), chronic migraine (n = 3) and trigeminal neuralgia (n = 3). Twelve patients were considered responders (80%), eight of whom were complete responders (100% pain freedom). The average duration of the treatment effect for each participant was 9.5 weeks (range 1-22 weeks). Six out of 15 patients reported mild and self-limiting side effects (40%).

Conclusion

A single infusion of IV lidocaine might be an effective and safe transitional treatment in refractory headache conditions with facial pain and trigeminal neuralgia. The sustained effect of repeated treatment cycles in some patients may suggest a role as long-term preventive therapy in some patients.

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.

Spinal Cord Stimulators: An Analysis of the Adverse Events Reported to the Australian Therapeutic Goods Administration

BACKGROUND

Spinal cord stimulators are used to treat intractable pain. Placebo-controlled trials of spinal cord stimulators typically involve short-term treatment and follow-up, so long-term safety and efficacy are unclear.

AIM

The aim of the study was to describe the adverse events relating to spinal cord stimulators reported to the Therapeutic Goods Administration of Australia between July 2012 and January 2019.

METHODS

Adverse events were coded by seriousness, severity, body system affected, type of event, action taken, and attribution of fault. Data on the number of stimulators implanted and removed were sourced from the Admitted Patient Care Minimum Data Set.

RESULTS

Five hundred twenty adverse events were reported for spinal cord stimulators. Most events were rated as severe (79%) or life-threatening (13%). Device malfunction was the most common event (56.5%). The most common action taken in response to an adverse event was surgical intervention with or without antibiotics (80%). The ratio of removals to implants was 4 per every 10 implanted.

CONCLUSIONS

Spinal cords stimulators have the potential for serious harm, and each year in Australia, many are removed. In view of the low certainty evidence of their long-term safety and effectiveness, our results raise questions about their role in providing long-term management of intractable pain.

Neuropathic Pain in Neurologic Disorders: A Narrative Review

Neuropathic pain is defined as a painful condition caused by neurological lesions or diseases. Sometimes, neurological disorders may also be associated with neuropathic pain, which can be challenging to manage. For example, multiple sclerosis (MS) may cause chronic centralized painful symptoms due to nerve damage. Other chronic neuropathic pain syndromes may occur in the form of post-stroke pain, spinal cord injury pain, and other central pain syndromes. Chronic neuropathic pain is associated with dysfunction, disability, depression, disturbed sleep, and reduced quality of life. Early diagnosis may help improve outcomes, and pain control can be an important factor in restoring function. There are more than 100 different types of peripheral neuropathy and those involving sensory neurons can provoke painful symptoms. Accurate diagnosis of peripheral neuropathy is essential for pain control. Further examples are represented by gluten neuropathy, which is an extraintestinal manifestation of gluten sensitivity and presents as a form of peripheral neuropathy; in these unusual cases, neuropathy may be managed with diet. Neuropathic pain has been linked to CoronaVirus Disease (COVID) infection both during acute infection and as a post-viral syndrome known as long COVID. In this last case, neuropathic pain relates to the host’s response to the virus. However, neuropathic pain may occur after any critical illness and has been observed as part of a syndrome following intensive care unit hospitalization.

The Anti-Inflammatory and Cytoprotective Efficiency of Curvularin, a Fungal Macrolactone against Lipopolysaccharide-Induced Inflammatory Response in Nucleus Pulposus Cells: An In Vitro Study

STUDY DESIGN

Developing an in vitro model for assessing the anti-inflammatory properties of curvularin.

PURPOSE

To evaluate the efficacy of natural fungal macrolactone as a therapeutic drug against lipopolysaccharide (LPS)-induced inflammation in primary human nucleus pulposus cells (NPCs) in vitro.

OVERVIEW OF LITERATURE

Lumbar disk disease is a common cause of lower back pain (LBP) and sciatica. It is an established fact that inflammation, rather than mechanical compression on the nerve root, plays a role in the cause of LBP and sciatica. Current treatment options for reducing inflammation are either nonsteroidal anti-inflammatory drugs or steroids, prolonged use of which can potentially lead to adverse effects such as gastrointestinal disturbances and renal and cardiac issues. Hence, there is a need for better antiinflammatory drugs with no or minimal complications for treating inflammation-induced LBP and sciatica. Curvularin (Cur), a fungal macrolactone, is known for its anti-inflammatory activity, but nothing is known about its impact on inflammation due to disk pathologies.

METHODS

Primary NPCs were cultured and characterized by flow cytometry and immunocytochemistry using the CD24 antibody and treated with 10 μg/mL LPS for 36 hours and then treated with Cur, betamethasone, and dexamethasone (10 μg/mL) for 48 hours, after which cell cycle analysis, cell viability assay, and gene expression studies (quantitative polymerase chain reaction [PCR] and quantitative real-time-PCR) were conducted. The NPCs treated with Cur downregulated the expression of pro-inflammatory cytokines (tumor necrosis factor-α, interleukin [IL]-1β, and IL-6); matrix metalloproteinases (MMPs; MMP-2 and MMP-3), ADAMTS; and apoptotic marker (cytochrome c).

RESULTS

In our study, Cur-treated cells showed enhanced expression of collagen 9A1 and insulin-like growth factor receptor 1, indicating the recovery of NPCs from inflammatory assault.

CONCLUSIONS

Based on observations, the anti-inflammatory properties of Cur render it an excellent drug molecule for treating disk degeneration nonsurgically, by direct injection into spinal disks when treating LBP and sciatica.

Exercise and Neuropathic Pain: A General Overview of Preclinical and Clinical Research

Neuropathic pain is a disease of the somatosensory system that is characterized by tingling, burning, and/or shooting pain. Medication is often the primary treatment, but it can be costly, thus there is an interest in understanding alternative low-cost treatments such as exercise. The following review includes an overview of the preclinical and clinical literature examining the influence of exercise on neuropathic pain. Preclinical studies support the hypothesis that exercise reduces hyperalgesia and allodynia in animal models of neuropathic pain. In human research, observational studies suggest that those who are more physically active have lower risk of developing neuropathic pain compared to those who are less active. Exercise studies suggest aerobic exercise training (e.g., 16 weeks); a combination of aerobic and resistance exercise training (e.g., 10–12 weeks); or high-intensity interval training (e.g., 15 weeks) reduces aspects of neuropathic pain such as worst pain over the past month, pain over the past 24 h, pain scores, or pain interference. However, not all measures of pain improve following exercise training (e.g., current pain, heat pain threshold). Potential mechanisms and future directions are also discussed to aid in the goal of understanding the role of exercise in the management of neuropathic pain. Future research using standardized methods to further understanding of the dose of exercise needed to manage neuropathic pain is warranted.

Effects of dose titration on adherence and treatment duration of pregabalin among patients with neuropathic pain: A MarketScan database study

OBJECTIVE

To examine pregabalin dose titration and its impact on treatment adherence and duration in patients with neuropathic pain (NeP).

METHODS

MarketScan database (2009-2014) was used to extract a cohort of incident adult pregabalin users with NeP who had at least 12 months of follow-up data. Any dose augmentation within 45 days following the first pregabalin claim was defined as dose titration. Adherence (measured by medication possession ratio/MPR) and persistence (measured as the duration of continuous treatment) were compared between the cohorts with and without dose titration. Logistic regressions and Cox proportional hazards models were used to identify the factors associated with adherence (MPR ≥ 0.8) and predictors of time to discontinuation.

RESULTS

Among the 5,186 patients in the analysis, only 18% of patients had dose titration. Patients who had dose titration were approximately 2.6 times as likely to be adherent (MPR ≥ 0.8) (odds ratio = 2.59, P < 0.001) than those who did not have dose titration. Kaplan-Meier analysis shows that the time to discontinuation or switch was significantly longer among patients who had dose titration (4.99 vs. 4.04 months, P = 0.009).

CONCLUSIONS

Dose titration was associated with improved treatment adherence and persistence among NeP patients receiving pregabalin. The findings will provide valuable evidence to increase physician awareness of dose recommendations in the prescribing information and to educate patients on the importance of titration and adherence.

Advances in the interventional management of neuropathic pain

The management of neuropathic pain, defined as pain as a result of a lesion or disease in the somatosensory nervous system, continues to be researched and explored. As conventional methods demonstrate limited long-term efficacy, there is a significant need to discover therapies that offer both longitudinal and sustained management of this highly prevalent disease, which can be offered through interventional therapies. Tricyclic antidepressants (TCAs), gabapentinoids, lidocaine, serotonin norepinephrine reuptake inhibitors (SNRIs), and capsaicin have been shown to be the most efficacious pharmacologic agents for neuropathic pain relief. With respect to infusion therapies, the use of intravenous (IV) ketamine could be useful for complex regional pain syndrome, fibromyalgia, and traumatic spinal cord injury. Interventional approaches such as lumbar epidurals are a reasonable treatment choice for up to 3 months of pain relief for patients who failed to respond to conservative treatment, with a “B” strength of recommendation and moderate certainty. Neuroablative procedures like pulsed radiofrequency ablation work by delivering electrical field and heat bursts to targeted nerves or tissues without permanently damaging these structures, and have been recently explored for neuropathic pain relief. Alternatively, neuromodulation therapy is now recommended as the fourth line treatment of neuropathic pain after failed pharmacological therapy but prior to low dose opioids. Finally, the intrathecal delivery of various pharmacologic agents, such as quinoxaline-based kappa-opioid receptor agonists, can be utilized for neuropathic pain relief. In this review article, we aim to highlight advances and novel methods of interventional management of neuropathic pain.

Cost-effectiveness of mirogabalin for the treatment of post-herpetic neuralgia in Taiwan

Objectives: To assess the cost-effectiveness of mirogabalin versus no treatment or pregabalin in patients with post-herpetic neuralgia (PHN) from a third-party perspective in Taiwan.Methods: A Markov model, which was developed with 2-week cycles and 1-year time horizon from the Taiwanese National Health Insurance Administration perspective, consisted of three health states: "mild," "moderate," and "severe" pain. Average daily pain score (ADPS) was assessed at the end of each cycle. Patients either remained in, or transitioned from, their assigned health state to a different state according to their pain score changes. All patients entered the model in "moderate" (4 ≤ ADPS <7) or "severe" (7 ≤ ADPS ≤ 10) pain health states. Efficacy data was informed by the pivotal Phase III trial, or by a network meta-analysis (NMA). Utility values were obtained from published literature and cost data from Taiwanese clinical experts and the Taiwan National Health Insurance Administration, using 2018 New Taiwan dollar (NT$). Probabilistic analysis was conducted to test the robustness of base case results.Results: Head-to-head analysis showed mirogabalin 30 mg to be cost-effective versus placebo in PHN. The deterministic analysis estimated a quality-adjusted life years gain of 0.041 at an ICER of NT$11,231 (US$365) versus no treatment (ICER: NT$274,567 [US$8,900]). In the NMAs, mirogabalin was cost-effective compared to pregabalin 150 mg (ICER: NT$515,881 [US$16,720]) and 300 mg (ICER: NT$201,671 [US$6,535]). Mirogabalin 30 mg dominated pregabalin 600 mg. Results from sensitivity and scenario analyses confirmed these results.Conclusion: Mirogabalin 30 mg, a potent and selective α2δ ligand, is a cost-effective treatment option for PHN in Taiwan, with ICERs below the willingness-to-pay threshold.

Quality of chronic pain interventional treatment guidelines from pain societies: Assessment with the AGREE II instrument

BACKGROUND AND OBJECTIVE

Procedures to relieve pain are performed frequently but there are concerns about patient selection, appropriate image guidance, frequency and training for physicians. Patients, healthcare providers, policymakers and licensing bodies seek evidence-based recommendations to use these interventions judiciously. In this review we appraised the methodological quality of recent clinical practice guidelines (CPGs) for interventional pain procedures.

DATABASE AND DATA TREATMENT

A systematic search of the medical literature was performed. Three trained appraisers independently evaluated the methodological quality of the CPGs using a validated instrument, the Appraisal of Guidelines in Research and Evaluation II (AGREE II). Six domains were considered: 1) score and purpose; 2) stakeholder involvement; 3) rigour of development; 4) clarity of presentation; 5) applicability and 6) editorial independence. A total of 23 items were scored. CPGs were deemed 'high quality' if a mean scaled score above 60% for rigour of development and for two other domains was obtained.

RESULTS

Mean scaled domain quality scores ranged from 61.72% to 69.99%. Despite being based on modest levels of evidence, two of the four included CPGs were considered to be of high methodological quality. The AGREE II scores across the four guidelines exhibited good inter-rater reliability. None of the guidelines involved key stakeholders such as patients, other healthcare providers, and payers.

CONCLUSIONS

All four CPGs were limited by a weak execution of the guideline development process. There is a need to develop methodologically sound evidence-based guidelines for the use of interventional pain procedures using a rigorous process that involves all relevant stakeholders.

SIGNIFICANCE

This systematic review appraises the methodological quality of existing CPGs on interventional procedures using a validated epidemiological tool (AGREE II). The aims of this review were to identify methodological and knowledge gaps in existing CPGs. Findings of this study will help in development of a high-quality CPG that can assist healthcare providers and patients in making informed decisions while ensuring that the right intervention is performed for the right patient at the right time. The quality of the evidence provided by the CPGs provided in support of their recommendations was also evaluated.

Electrocatheter-mediated High-voltage Pulsed Radiofrequency of the Dorsal Root Ganglion in the Treatment of Chronic Lumbosacral Neuropathic Pain: A Randomized Controlled Study

OBJECTIVES

Despite the interest in scientific community, there is still poor evidence about pulsed radiofrequency (PRF) efficacy in the treatment of neuropathic pain. In order to determine whether high-voltage PRF and epidural adhesiolysis (PRF-EA) showed better results than epidural adhesiolysis alone (EA), a randomized, double-blind, comparative-effectiveness study was conducted in patients with chronic lumbosacral radiating pain and neuropathic features.

MATERIALS AND METHODS

A total of 41 patients were randomly allocated to 2 groups. Twenty-one patients were randomized to receive 2 cycles of 240 seconds high-voltage PRF followed by the injection of local anesthetics, hyaluronidase, and betamethasone, whereas 20 patients underwent sham stimulation followed by adhesiolysis. The treatment was delivered at the affected lumbosacral roots and patients, treating physicians and assessors were blinded to intervention.

RESULTS

A significant reduction of radiating pain was observed in mean Numeric Rating Scale score at follow-up. A change of -3.43 versus -1.75 (P=0.031) after 1 month and -3.34 versus -0.80 (P=0.005) after 6 months was reported in patients undergoing PRF-EA in comparison with EA, respectively. After 1 month, 57% of patients in the PRF-EA group experienced a pain reduction of ≥50% versus only 25% of patients allocated to EA (P=0.037). Improvement decreased to 48% in the PRF-EA group whereas only 10% of EA reported significant pain relief after 6 months (P=0.008).

DISCUSSION

High-voltage PRF of dorsal root ganglion delivered through multifunctional electrode provided significant pain relief and may be considered a valuable treatment in chronic lumbosacral radicular pain with neuropathic features.

Evaluation Through Transcutaneous Tissue Oximetry (Near Infrared Spectroscopy) of Spinal Cord Stimulation in Patients With Complex Regional Pain Syndrome Type I

OBJECTIVE

One of the physiopathological hypothesis behind complex regional pain syndrome (CRPS) type I involves the deep-tissue hypoxia of the affected areas. Spinal cord stimulation (SCS) appears to be effective in the treatment of these patients. We evaluated whether ESCS modifies tissue oxygen saturation (StO₂ ) measured with near-infrared spectroscopy (NIRS) in the affected limbs in patients diagnosed with CRPS type I.

MATERIALS AND METHODS

Nonrandomized, cross-sectional study that evaluated 16 patients with CRPS type I who were receiving SCS applied to the posterior cords. NIRS was used to evaluate baseline StO₂ (primary outcome) and variations in StO₂ (secondary outcome) during an ischemia-reperfusion test performed using a vascular occlusion test, comparing the hands of limbs unilaterally affected by CRPS type I with the unaffected contralateral hands. We also determined whether the variations in StO₂ were related to a modification in the percentage of subjective pain improvement and in the visual analog scale score.

RESULTS

The baseline StO₂ of the affected hands was significantly higher than that of the unaffected hands (mean 4.7%; 95% confidence interval: 1.41, 6.7; p = 0.005). Variations in StO₂ during the ischemia-reperfusion test revealed no differences between affected and unaffected hands. No significant correlations were detected between baseline StO₂ values or variations in StO₂ during the vascular occlusion test and the pain measurements.

CONCLUSIONS

Baseline StO₂ evaluated by NIRS was greater in the affected hands of patients with CRPS type I treated with SCS than in the unaffected, contralateral hands.

Spinal Cord Stimulation

Spinal cord stimulation (SCS) has been well established as a safe and effective treatment of pain derived from a wide variety of etiologies. Careful patient selection including a rigorous trial period and psychological evaluation are essential. When patients proceed to permanent implantation, various considerations should be made, such as the type of lead, type of anesthesia, and waveform patterns for SCS. This article discusses the common indications for SCS, patient selection criteria, and pertinent outcomes from randomized clinical trials related to common indications treated with SCS. Technical considerations, such as type of implant, anesthesia, and programming, are also discussed.

Toward a comprehensive evidence map of overview of systematic review methods: paper 2-risk of bias assessment; synthesis, presentation and summary of the findings; and assessment of the certainty of the evidence

BACKGROUND

Overviews of systematic reviews (SRs) attempt to systematically retrieve and summarise the results of multiple systematic reviews. This is the second of two papers from a study aiming to develop a comprehensive evidence map of the methods used in overviews. Our objectives were to (a) develop a framework of methods for conducting, interpreting and reporting overviews (stage I)-the Methods for Overviews of Reviews (MOoR) framework-and (b) to create an evidence map by mapping studies that have evaluated overview methods to the framework (stage II). In the first paper, we reported findings for the four initial steps of an overview (specification of purpose, objectives and scope; eligibility criteria; search methods; data extraction). In this paper, we report the remaining steps: assessing risk of bias; synthesis, presentation and summary of the findings; and assessing certainty of the evidence arising from the overview.

METHODS

In stage I, we identified cross-sectional studies, guidance documents and commentaries that described methods proposed for, or used in, overviews. Based on these studies, we developed a framework of possible methods for overviews, categorised by the steps in conducting an overview. Multiple iterations of the framework were discussed and refined by all authors. In stage II, we identified studies evaluating methods and mapped these evaluations to the framework.

RESULTS

Forty-two stage I studies described methods relevant to one or more of the latter steps of an overview. Six studies evaluating methods were included in stage II. These mapped to steps involving (i) the assessment of risk of bias (RoB) in SRs (two SRs and three primary studies, all reporting evaluation of RoB tools) and (ii) the synthesis, presentation and summary of the findings (one primary study evaluating methods for measuring overlap).

CONCLUSION

Many methods have been described for use in the latter steps in conducting an overview; however, evaluation and guidance for applying these methods is sparse. The exception is RoB assessment, for which a multitude of tools exist-several with sufficient evaluation and guidance to recommend their use. Evaluation of other methods is required to provide a comprehensive evidence map.

Consensus Guidelines on the Use of Intravenous Ketamine Infusions for Chronic Pain From the American Society of Regional Anesthesia and Pain Medicine, the American Academy of Pain Medicine, and the American Society of Anesthesiologists

BACKGROUND

Over the past 2 decades, the use of intravenous ketamine infusions as a treatment for chronic pain has increased dramatically, with wide variation in patient selection, dosing, and monitoring. This has led to a chorus of calls from various sources for the development of consensus guidelines.

METHODS

In November 2016, the charge for developing consensus guidelines was approved by the boards of directors of the American Society of Regional Anesthesia and Pain Medicine and, shortly thereafter, the American Academy of Pain Medicine. In late 2017, the completed document was sent to the American Society of Anesthesiologists' Committees on Pain Medicine and Standards and Practice Parameters, after which additional modifications were made. Panel members were selected by the committee chair and both boards of directors based on their expertise in evaluating clinical trials, past research experience, and clinical experience in developing protocols and treating patients with ketamine. Questions were developed and refined by the committee, and the groups responsible for addressing each question consisted of modules composed of 3 to 5 panel members in addition to the committee chair. Once a preliminary consensus was achieved, sections were sent to the entire panel, and further revisions were made. In addition to consensus guidelines, a comprehensive narrative review was performed, which formed part of the basis for guidelines.

RESULTS

Guidelines were prepared for the following areas: indications; contraindications; whether there was evidence for a dose-response relationship, or a minimum or therapeutic dose range; whether oral ketamine or another N-methyl-D-aspartate receptor antagonist was a reasonable treatment option as a follow-up to infusions; preinfusion testing requirements; settings and personnel necessary to administer and monitor treatment; the use of preemptive and rescue medications to address adverse effects; and what constitutes a positive treatment response. The group was able to reach consensus on all questions.

CONCLUSIONS

Evidence supports the use of ketamine for chronic pain, but the level of evidence varies by condition and dose range. Most studies evaluating the efficacy of ketamine were small and uncontrolled and were either unblinded or ineffectively blinded. Adverse effects were few and the rate of serious adverse effects was similar to placebo in most studies, with higher dosages and more frequent infusions associated with greater risks. Larger studies, evaluating a wider variety of conditions, are needed to better quantify efficacy, improve patient selection, refine the therapeutic dose range, determine the effectiveness of nonintravenous ketamine alternatives, and develop a greater understanding of the long-term risks of repeated treatments.

Efficacy and safety of pulsed radiofrequency and steroid injection for intercostobrachial neuralgia in postmastectomy pain syndrome - A clinical trial

Background:

Breast cancer is a common neoplastic tumor in women, and the postmastectomy pain syndrome has been reported frequently after surgical treatment. The injury of the intercostobrachial nerve is considered the major cause of this type of pain.

Purpose:

Evaluation of efficacy and safety of pulsed radiofrequency (PRF) and steroid injection on the 2^nd and 3^rd thoracic (T2 and T3) dorsal root ganglions (DRGs) for intercostobrachial neuralgia (ICBN) postmastectomy.

Patients and Methods:

This study was conducted on 100 patients with ICBN postmastectomy. The PRF waves were applied for 120 s twice on T2 and T3 DRGs then 1 ml of 4 mg dexamethasone and 1 ml of bupivacaine 0.25% were injected at each level then the technique was repeated three times 1 week apart for each patient.

Results:

After 6 months from the latest intervention, the mean of visual analog scale dropped from 7.48 to 4.7 (P = 0.005712) and the mean of the quality of life scale improved to 6.88 after being 4.66 (P < 0.00001) before the intervention and 64.68% of the patients decided that they would certainly repeat the procedure if they could go back in time and 66.64% would certainly recommend the same procedure to a family member. The analgesics consumption decreased mainly in the 1^st month but increased again after 6 months (not significant). No serious complications were recorded.

Conclusions:

PRF and steroid injection on T2 and T3 DRGs assumed an effective and safe method for ICBN postmastectomy treatment.

A review of Neuropathic Pain: From Guidelines to Clinical Practice

Neuropathic pain is a chronic condition representing a significant burden for patients, society, and healthcare systems. The prevalence of neuropathic pain in the general population has been estimated at 7–8% and is expected to increase in the future. Neuropathic pain differs from nociceptive pain and requires a different therapeutic approach; and the management of neuropathic pain is complicated and challenging. This chapter discusses clinical practice guidelines for neuropathic pain and their usefulness in clinical practice.

Funding: Pfizer, Italy.

Minimally invasive procedures for neuropathic pain

Neuropathic pain is "pain arising as a direct consequence of a lesion or disease affecting the somatosensory system". The prevalence of neuropathic pain ranges from 7 to 11% of the population and minimally invasive procedures have been used to both diagnose and treat neuropathic pain. Diagnostic procedures consist of nerve blocks aimed to isolate the peripheral nerve implicated, whereas therapeutic interventions either modify or destroy nerve function. Procedures that modify how nerves function include epidural steroid injections, peripheral nerve blocks and sympathetic nerve blocks. Neuroablative procedures include radiofrequency ablation, cryoanalgesia and neurectomies. Currently, neuromodulation with peripheral nerve stimulators and spinal cord stimulators are the most evidence-based treatments of neuropathic pain.

Clinical practice guidelines for the management of neuropathic pain: a systematic review

BACKGROUND

The management of neuropathic pain (NP) is challenging despite it being the recent focus of extensive research. A number of clinical practice guidelines (CPGs) for the management of NP have been published worldwide over the past 2 decades. This study aimed to assess the quality of these CPGs.

METHODS

We performed a systematic review of published CPGs for the management of NP. Three reviewers independently assessed the quality of the CPGs using the Appraisal of Guidelines Research and Evaluation II (AGREE-II) instrument, and recommendations of CPGs were also appraised.

RESULTS

A total of 16 CPGs were included. Thirteen CPGs were developed using an evidence-based approach, and the remaining CPGs were produced by consensus panels. None of CPGs obtained a score greater than 50% in all six AGREE II instrument domains mainly owing to poor performance in the "Applicability" domain. The highest score of the CPGs was achieved in "Clarity and Presentation" domain, followed by "Scope and Purpose" and "Editorial Independence" domains, and the lowest scores were found the in "Applicability" domain. The majority of the CPG recommendations on the management of patients with NP were relatively consistent, especially regarding the recommendation of stepwise treatment with medication.

CONCLUSIONS

Greater efforts are needed not only to improve the quality of development and presentation of the CPGs, but also to provide more efficacy evidence for the management of patients with NP.

Managing Neuropathic Pain

Neuropathic pain (NP) arises from injuries or diseases affecting the somatosensory component of the nervous system at any level of the peripheral or central nervous system. NP is diagnosed based on common neurologic signs and symptoms. NP is best treated with a combination of multiple therapeutic approaches, and treatments include conservative, complementary, medical, interventional, and surgical treatment modalities. Goals of treatment are the same as in pain management and include improvement in pain control and in coping skills as well as restoration of functional status. Most patients with NP benefit most from an individualized, multimodal approach that emphasizes both pain and function.

[Practice of regional anesthesia for chronic pain patients in specialized pain services : A nationwide survey in Germany]

BACKGROUND

The prevalence of chronic pain has been estimated to be 19% in the European population and criteria for disabling chronic pain were found in approximately 7% of the German population. Clinical care for these patients is provided in ambulant and hospital-associated facilities. In this context, invasive interventions are part of the diagnosis and treatment of several specific diseases. Current data on the structure of clinical care based regional anesthesia for chronic pain patients in Germany are not available.

OBJECTIVE

This study focused on the application and practice of interventional procedures in the context of pain management.

MATERIAL AND METHODS

An internet-based survey addressing pain facilities and pain specialists in Germany was carried out. The response rate achieved 54%.

RESULTS

Overall 79% of the pain therapists who responded included regional anesthesia techniques in the therapeutic spectrum in up to 25% of patients. The leading indications for invasive procedures were back pain and neuropathic pain. Two thirds of the therapists reported performing a series of blocks. A reduction of pain intensity of 30-50% was often reported as a sufficient criterion for the success of regional anesthesia interventions. Typically, approximately 40% of the chronic pain patients undergoing a series of blocks achieved sufficient pain relief which lasted most commonly for 12 weeks up to 6 months.

CONCLUSION

This survey describes the current structures of specialized pain facilities for regional anesthesia in Germany including responses from predominantly anesthesiologists in a hospital-associated setting. In light of the limited evidence in the literature there is no consensus on the interventional therapeutic management of chronic pain. Especially the application of a series of blocks and the frequency as well as criteria to support continuing or terminating a series of regional anesthesia interventions are not sufficiently evaluated. This survey also gives an incentive for a possible revision of the existing practice in regional anesthesia in the context of multimodal therapy and currently existing guidelines in future clinical studies.

Pharmacological management of chronic neuropathic pain: revised consensus statement from the Canadian Pain Society

BACKGROUND

Neuropathic pain (NeP), redefined as pain caused by a lesion or a disease of the somatosensory system, is a disabling condition that affects approximately two million Canadians.

OBJECTIVE

To review the randomized controlled trials (RCTs) and systematic reviews related to the pharmacological management of NeP to develop a revised evidence-based consensus statement on its management.

METHODS

RCTs, systematic reviews and existing guidelines on the pharmacological management of NeP were evaluated at a consensus meeting in May 2012 and updated until September 2013. Medications were recommended in the consensus statement if their analgesic efficacy was supported by at least one methodologically sound RCT (class I or class II) showing significant benefit relative to placebo or another relevant control group. Recommendations for treatment were based on the degree of evidence of analgesic efficacy, safety and ease of use.

RESULTS

Analgesic agents recommended for first-line treatments are gabapentinoids (gabapentin and pregabalin), tricyclic antidepressants and serotonin noradrenaline reuptake inhibitors. Tramadol and controlled-release opioid analgesics are recommended as second-line treatments for moderate to severe pain. Cannabinoids are now recommended as third-line treatments. Recommended fourth-line treatments include methadone, anticonvulsants with lesser evidence of efficacy (eg, lamotrigine, lacosamide), tapentadol and botulinum toxin. There is support for some analgesic combinations in selected NeP conditions.

CONCLUSIONS

These guidelines provide an updated, stepwise approach to the pharmacological management of NeP. Treatment should be individualized for each patient based on efficacy, side-effect profile and drug accessibility, including cost. Additional studies are required to examine head-to-head comparisons among analgesics, combinations of analgesics, long-term outcomes and treatment of pediatric, geriatric and central NeP.

[Interventional pain therapy. Results of a survey among specialized pain physicians in Germany]

BACKGROUND

Interventional pain therapy aims to treat pain which is refractory to pharmacologic and noninterventional treatment. Due to the partly lacking evidence and recommendations it remains unclear when interventional methods should be applied within the treatment pathway. This study assesses the current state of interventional methods in Germany and their leading indications comparing with the recommendations found in the literature.

METHODS

An online survey was conducted among German physicians specialized in pain therapy concerning the number of interventions they perform per quarter, which supporting measures they use, and their indications for sympathetic blocks, sensory blocks, intrathecal administration, and spinal cord stimulation.

RESULTS

A total of 109 physicians (23.5 %) participated in the survey. Blocks are most often performed on the stellate ganglion (94 %) and on the superior cervical ganglion (82 %). They are supported by anatomical landmarks and less often by imaging control. Both classic neuropathic pain diagnoses (e.g., complex regional pain syndrome) and diagnoses with a neuropathic pain component (e.g., peripheral arterial disease, tumor pain, and back pain) were considered as indications to perform interventional procedures.

CONCLUSION

Although there is no clear evidence on interventional procedures in the current literature, these methods are often performed by the respondents. Anatomic landmarks are most frequently used for orientation. The German pain physicians who responded consider especially neuropathic pain as an indication to perform interventional procedures for pain therapy.

Percutaneous spinal cord stimulation for chronic pain: indications and patient selection

Percutaneous spinal cord stimulation has a clinical benefit in selected patients with chronic neuropathic pain related to failed back surgery syndrome and complex regional pain syndrome. Patients with other peripheral neuropathic pain syndromes may also respond favorably. The cause of the chronic pain must be established to rule out remediable causes. Drug abuse or aberrant drug-related behaviors should be assessed before proceeding. A psychological evaluation identifies patients who may not benefit. Risk factors for infection should be corrected where possible. This safe, reversible treatment should be considered early for patients with intractable peripheral neuropathic pain.

Effectiveness and tolerability of low-dose oral oxycodone/naloxone added to anticonvulsant therapy for noncancer neuropathic pain: an observational analysis

BACKGROUND

Opioids may alleviate chronic neuropathic pain (NP), but are considered second/third-line analgesia due to their poor gastrointestinal (GI) tolerability. A fixed combination of prolonged-release oxycodone and naloxone (OXN) has been developed to overcome the GI effects. The aim of this analysis was to evaluate analgesic effectiveness and tolerability of low-dose OXN in patients with moderate-to-severe noncancer NP despite analgesia.

METHODS

This retrospective observation of consecutive adult patients, treated open-label for 8 weeks at a single Italian centre, evaluated effectiveness (pain intensity numerical rating scale [NRS], Patients' Global Impression of Change [PGIC], Douleur Neuropathique 4 inventory [DN4] and Chronic Pain Sleep Inventory [CPSI]), doses of daily OXN and adjuvant medication, rescue paracetamol use, bowel function index (BFI), laxative use, and safety.

RESULTS

Of 200 patients (mean age 65.9 years; 54% female) with NP included in the analysis; 97% completed 8 weeks' treatment. At the observation start, all patients were taking anticonvulsants and complained of constipation, and 60% were receiving opioids. Pain intensity and DN4 score decreased significantly by endpoint (NRS p < 0.0001; DN4 p < 0.0001) and need for rescue analgesics abated. Reduction in pain intensity throughout the observation was similar regardless of NP aetiology. According to PGIC, 87.8% of patients were much/extremely improved, CPSI (p < 0.0001) and BFI were significantly improved (p < 0.0001) and laxative use decreased. No differences were found between patients <65 years vs those ≥65 years. OXN was generally well tolerated.

STUDY LIMITATIONS

Study limitations including the retrospective observational design, the lack of a control group and the single-centre design may limit the generalizability of our findings.

CONCLUSIONS

Low-dose OXN (25.0 ± 12.5 mg/day) added to anticonvulsants was highly effective in controlling noncancer NP of varied aetiology, with reduced need for rescue analgesia and improved quality of sleep, and was well tolerated, with improved bowel function and reduced laxative use. The efficacy and tolerability of OXN demonstrated in this real-world setting suggest its utility in this difficult to manage patient population.

Relationship between bone mineral density and the frequent administration of epidural steroid injections in postmenopausal women with low back pain

BACKGROUND

Epidural steroid injection (ESI) is one of the most common nonsurgical treatments for low back pain. In general, corticosteroid therapy often results in bone loss and osteoporosis. In previous studies, bone mineral density (BMD) was evaluated after epidural injections of relatively small numbers and relatively low total doses of corticosteroids. However, the relationship between BMD and multiple ESIs remains to be elucidated.

OBJECTIVE

To explore the relationship between BMD and multiple ESIs in postmenopausal women with low back pain.

METHODS

Medical records of postmenopausal women with low back pain treated with or without ESIs were reviewed. BMD was measured in the lumbar spine, femoral neck and total femur after the treatments. A total of 71 patients were divided into two groups: group 1 included patients who had received non-ESI medications; and group 2 included those who had received ESIs >10 times, with a cumulative administered triamcinolone dose >200 mg.

RESULTS

Patients in group 2 showed lower BMD in the femoral neck and total femur. However, no significant intergroup differences in the BMD of the lumbar spine were observed. The prevalences of osteoporosis and osteopenia in the lumbar spine and femoral neck were significantly higher in group 2; these patients also had lower femoral neck BMD Z-scores.

CONCLUSIONS

Multiple ESIs (approximately 14 injections with a cumulative triamcinolone dose of approximately 400 mg) can reduce BMD in postmenopausal women with low back pain.