Sympathetic blocks provided sustained pain relief in a patient with refractory painful diabetic neuropathy

Lumbar Sympathetic Block Leading to Increased Arterial Diameter and Blood Flow: A Mechanism of Therapeutic Benefit

Lumbar sympathetic blocks (LSBs) have long been used for the treatment of chronic lower extremity pain and for conditions such as complex regional pain syndrome (CRPS). With a better understanding of the autonomic nervous system and its function, these blocks have grown in their utility. Through this growth, however, our understanding of sympathetic-mediated pain is still vaguely understood. Here, we present a case of a patient who underwent a point-of-care ultrasound (POCUS) before and after an LSB, and we were able to show significant dilation of the posterior tibial artery (PTA) following the block. We propose that this arterial dilation plays a mechanistic role in providing pain relief to patients who undergo LSB. This increased blood flow can not only enhance healing properties to surrounding tissues but also allow for nitric oxide to play potential regulatory roles in pain pathways. Here, we also review potential mechanisms of the amelioration of sympathetic-mediated pain as well as the potential utilization of LSBs and neuromodulation in treating visceral pathologies through a better understanding of visceral somatic relationships.

A Systematic Guideline by the ASPN Workgroup on the Evidence, Education, and Treatment Algorithm for Painful Diabetic Neuropathy: SWEET

Introduction

Painful diabetic neuropathy (PDN) is a leading cause of pain and disability globally with a lack of consensus on the appropriate treatment of those suffering from this condition. Recent advancements in both pharmacotherapy and interventional approaches have broadened the treatment options for PDN. There exists a need for a comprehensive guideline for the safe and effective treatment of patients suffering from PDN.

Objective

The SWEET Guideline was developed to provide clinicians with the most comprehensive guideline for the safe and appropriate treatment of patients suffering from PDN.

Methods

The American Society of Pain and Neuroscience (ASPN) identified an educational need for a comprehensive clinical guideline to provide evidence-based recommendations for PDN. A multidisciplinary group of international experts developed the SWEET guideline. The world literature in English was searched using Medline, EMBASE, Cochrane CENTRAL, BioMed Central, Web of Science, Google Scholar, PubMed, Current Contents Connect, Meeting Abstracts, and Scopus to identify and compile the evidence for diabetic neuropathy pain treatments (per section as listed in the manuscript) for the treatment of pain. Manuscripts from 2000-present were included in the search process.

Results

After a comprehensive review and analysis of the available evidence, the ASPN SWEET guideline was able to rate the literature and provide therapy grades for most available treatments for PDN utilizing the United States Preventive Services Task Force criteria.

Conclusion

The ASPN SWEET Guideline represents the most comprehensive review of the available treatments for PDN and their appropriate and safe utilization.

Issues and challenges in diabetic neuropathy management: A narrative review

Diabetic neuropathy (DN) is a devastating disorder with an increasing prevalence globally. This epidemic can pose a critical burden on individuals and com-munities, subsequently affecting the productivity and economic output of a country. With more people living a sedentary lifestyle, the incidence of DN is escalating worldwide. Many researchers have relentlessly worked on ways to combat this devastating disease. Their efforts have given rise to a number of commercially available therapies that can alleviate the symptoms of DN. Unfortunately, most of these therapies are only partially effective. Worse still, some are associated with unfavorable side effects. This narrative review aims to highlight current issues and challenges in the management of DN, especially from the perspective of molecular mechanisms that lead to its progression, with the hope of providing future direction in the management of DN. To improve the approaches to diabetic management, the suggested resolutions in the literature are also discussed in this review. This review will provide an in-depth understanding of the causative mechanisms of DN, apart from the insights to improve the quality and strategic approaches to DN management.

Quantitative Analysis of Real-Time Infrared Thermography for the Assessment of Lumbar Sympathetic Blocks: A Preliminary Study

Lumbar sympathetic blocks (LSBs) are commonly performed to treat pain ailments in the lower limbs. LSBs involve injecting local anesthetic around the nerves. The injection is guided by fluoroscopy which is sometimes considered to be insufficiently accurate. The main aim was to analyze the plantar foot skin temperature data acquired while performing LSBs in patients with complex regional pain syndrome (CRPS) affecting the lower limbs. Forty-four LSBs for treating lower limb CRPS in 13 patients were assessed. Pain medicine physicians visualized the infrared thermography (IRT) video in real time and classified the performance depending on the observed thermal changes within the first 4 min. Thirty-two percent of the cases did not register temperature variations after lidocaine was injected, requiring the needle to be relocated. Differences between moments are indicated using the 95% confidence intervals of the differences (CI 95%), the Cohen effect size (ES) and the significance (p value). In successful cases, after injecting lidocaine, increases at minute 7 for the mean (CI 95% (1.4, 2.1 °C), p < 0.001 and ES = 0.5), at minute 5 for maximum temperature (CI 95% (2.3, 3.3 °C), p < 0.001 and ES = 0.6) and at minute 6 for SD (CI 95% (0.2, 0.3 °C), p < 0.001 and ES = 0.5) were observed. The results of our preliminary study showed that the measurement of skin temperature in real time by infrared thermography is valuable for assessing the success of lumbar sympathetic blocks.

Neuropathic Pain in the Elderly

Neuropathic pain due to a lesion or a disease of the somatosensory system often affects older people presenting several comorbidities. Moreover, elderly patients are often poly-medicated, hospitalized and treated in a nursing home with a growing risk of drug interaction and recurrent hospitalization. Neuropathic pain in the elderly has to be managed by a multidimensional approach that involves several medical, social and psychological professionals in order to improve the quality of life of the patients and, where present, their relatives.

Interventional Modalities to Treat Complex Regional Pain Syndrome

PURPOSE OF REVIEW

Complex regional pain syndrome (CRPS) is a debilitating pain condition that often requires a multidisciplinary approach including medication, physical therapy, occupational therapy, psychological therapy, and interventional procedures to restore the patient's quality of life. This article reviews the interventional treatments for pain resulting from CRPS.

RECENT FINDINGS

Sympathetic nerve blocks (stellate ganglion and lumbar sympathetic) are the first-line interventional treatment options for patients with CRPS of the upper and lower extremities, respectively. Fluoroscopic techniques for lumbar sympathetic blocks have not significantly changed throughout the years. However, both novel fluoroscopic and ultrasound approaches to stellate ganglion blockade have arisen. In addition, novel neuromodulation therapies to treat CRPS have been developed to include new waveforms with dorsal column stimulation and entirely new nerve targets such as dorsal root ganglion stimulation. This paper will review the latest interventional treatment options available for the treatment of CRPS.

Continuous Lumbar Sympathetic Blockade Enhances the Effect of Lumbar Sympatholysis on Refractory Diabetic Neuropathy: A Randomized Controlled Trial

INTRODUCTION

There are a number of options for the symptomatic treatment of peripheral neuropathy, but the overall treatment outcomes remain unsatisfactory.

METHODS

A total of 60 patients with refractory diabetic neuropathy were randomly assigned to two groups. Patients in Group A were treated with computed tomography (CT)-guided sympathetic neurolysis with alcohol, and patients in Group B were treated with a combined therapy of CT-guided catheterization to achieve continuous lumbar block for 4 weeks followed by neurolysis with alcohol administered via the catheter. The outcomes of these two treatment strategies were then analyzed in terms of pain relief, blood flow in the lower limb microcirculation, plasma levels of inflammatory mediators, and complications.

RESULTS

The visual analog scale (VAS) pain scores of all patients after treatment decreased significantly at the different evaluation time points compared with pre-treatment values, with the intergroup analysis revealing that the VAS scores were lower in Group B patients than in Group A patients at all post-treatment time points. Skin temperature, capillary filling time, and blood oxygen saturation level were significantly improved in all patients at the 1- and 7-day post-treatment assessment compared to pre-treatment values, but patients in Group B showed a greater improvement. The plasma levels of inflammatory mediators were lower in all patients at the 7-day post-treatment assessment compared to pre-treatment values, with those of patients in Group B being statistically significantly lower than those of patients in Group A.

CONCLUSION

Combined treatment with continuous lumbar sympathetic block followed by neurolysis with alcohol provided more benefit in all assessed outcomes than sympathetic alcohol neurolysis alone. The results show that the procedures were associated with satisfactory safety outcomes and sustained analgesic effects, thereby providing clinical evidence supporting the use of this novel treatment for patients with painful diabetic neuropathy.

Lumbar sympathetic treatment in the management of lower limb pain

The sympathetic system has been a target for interventional treatment since the early half of the 20th century. One area targeted for treatment has been the lumbar sympathetics for lower limb pain. Physicians have treated various neuropathic and ischemic conditions employing the use of sympathetic procedures as a mode of treatment, yet the studies strongly supporting the utility of the procedure have been lacking. Anatomic studies have brought to light the complexity and variation that exists with identifying the locations of the ganglion. Studies have investigated the different methods to determine the highest yield and less risky approaches in performing the technique. Many studies have reported positive results with blockade and neurolysis, but review of the literature reveals poor strength quality and small sample population. These reports should be viewed as building blocks for more robust investigation. Interpretation of the results should be performed with caution, and translation into common practice implemented on a case by case basis.