The prolonged analgesic effect of epidural ropivacaine in a rat model of neuropathic pain

Molecular pathway of pancreatic cancer-associated neuropathic pain

The pancreas is a heterocrine gland that has both exocrine and endocrine parts. Most pancreatic cancer begins in the cells that line the ducts of the pancreas and is called pancreatic ductal adenocarcinoma (PDAC). PDAC is the most encountered pancreatic cancer type. One of the most important characteristic features of PDAC is neuropathy which is primarily due to perineural invasion (PNI). PNI develops tumor microenvironment which includes overexpression of fibroblasts cells, macrophages, as well as angiogenesis which can be responsible for neuropathy pain. In tumor microenvironment inactive fibroblasts are converted into an active form that is cancer-associated fibroblasts (CAFs). Neurotrophins they also increase the level of Substance P, calcitonin gene-related peptide which is also involved in pain. Matrix metalloproteases are the zinc-associated proteases enzymes which activates proinflammatory interleukin-1β into its activated form and are responsible for release and activation of Substance P which is responsible for neuropathic pain by transmitting pain signal via dorsal root ganglion. All the molecules and their role in being responsible for neuropathic pain are described below.

Effects of Local Anesthetics With or Without Steroids in High-Volume Transforaminal Epidural Blocks for Lumbar Disc Herniation: A Randomized, Double-Blind, Controlled Trial

BACKGROUND

Lumbar transforaminal epidural block (TFEB) is an effective treatment modality for radicular pain due to lumbar disc herniation (LDH). The addition of steroids is more effective than local anesthetic alone in TFEBs for patients with LDH. Moreover, the efficacy of TFEBs has been reported to be positively correlated with the volume of injectate. We hypothesized that high-volume TFEBs without steroids effectively alleviate axial back and radicular pain associated with LDH. This study compared the efficacy of high-volume TFEBs with vs. without steroids for the management of the axial and radicular pain caused by LDH.

METHODS

A total of 54 patients were randomly assigned to either group L or group D. Patients in group L received 8-mL injections of 0.33% lidocaine only. Patients in group D received 8-mL injections of 0.33% lidocaine with 5 mg of dexamethasone. The primary outcomes were pain intensity at baseline and 4 weeks after the procedure. The secondary outcomes included the change of functional disability between baseline and 4 weeks after the procedure, pain scores during injection, and adverse effects.

RESULTS

Both groups showed a significant reduction in axial and radicular pain and improvement in the functional status at the outpatient visit 4 weeks after TFEB. However, there were no significant differences between the groups in terms of changes in back pain (10.00 [20.00] vs. 10.00 [22.50]; P = 0.896) or radicular pain (5.00 [20.00] vs. 10.00 [12.50]; P = 0.871).

CONCLUSION

High-volume TFEBs with and without steroid administration yielded similar significant pain reductions and functional improvements among LDH patients 4 weeks after the procedure.

A Comprehensive Review of the Treatment and Management of Myofascial Pain Syndrome

PURPOSE OF REVIEW

Myofascial pain syndrome (MPS) is a musculoskeletal pain condition that stems from localized, taut regions of skeletal muscle and fascia, termed trigger points. The purpose of this comprehensive review is to provide updated information on prevalence, pathophysiology, and treatment modalities with a focus on interventional modalities in managing MPS.

RECENT FINDINGS

Though MPS can present acutely, it frequently presents as a chronic condition, affecting up to 85% of adults during their lifetime. MPS is an often-overlooked component of pain with overarching effects on society, including patient quality of life, physical and social functioning, emotional well-being, energy, and costs on health care. The prevalence of MPS is generally increased among patients with other chronic pain disorders and has been associated with various other conditions such as bladder pain syndrome, endometriosis, and anxiety. MPS is poorly understood and remains a challenging condition to treat. Non-pharmacologic treatment modalities such as acupuncture, massage, transcutaneous electrical stimulation, and interferential current therapy may offer relief to some patients with MPS. Additional studies are warranted to get a better understanding of managing myofascial pain.

Comparison of effectiveness for fluoroscopic cervical interlaminar epidural injections with or without steroid in cervical post-surgery syndrome

Background

Neck and back pain are leading sources of disability placing substantial burden on health care systems. Surgical interventions in managing chronic neck pain secondary to various disorders continue to increase. Even though surgical interventions are effective, a significant proportion of patients continue to have symptomatology and develop cervical post-surgery syndrome. This study was performed to know the effectiveness of cervical interlaminar epidural injections with or without steroids.

Methods

The effectiveness of fluoroscopic cervical interlaminar epidural injections in post-surgery syndrome was evaluated in a randomized, active controlled trial. The study population included 116 patients assigned to 2 groups. Group 1 received cervical interlaminar epidural injections with local anesthetic alone and Group 2 received injection with local anesthetic and steroids. The main outcomes were defined as significant improvement (greater than 50%) of pain relief using the numeric rating scale and/or functional status improvement using the Neck Disability Index (NDI).

Results

Both groups had similar results with significant improvement (≥ 50% pain relief and functional status improvement) in 69% of the patients in Group I, whereas, in Group II, 71% of the patients showed significant improvement at the end of 2 years. During a 2-year period, the average number of procedures was 5 to 6, with an average of approximately 12 weeks of significant improvement per procedure.

Conclusions

Fluoroscopic cervical interlaminar epidural injections administered in cervical post-surgery syndrome using local anesthetic, regardless of the use of steroids, may be effective in approximately 70% of the patients at 2-year follow-up.

Intraperitoneal ropivacaine and early postoperative pain and postsurgical outcomes after laparoscopic herniorrhaphy in toddlers: a randomized clinical trial

BACKGROUND

Postoperative pain can cause physiological distress, postoperative complications, and extended lengths of hospitalized stay. In children, management of postoperative pain is still recognized as being inadequate.

OBJECTIVE

The aim of this trial was to investigate the effects of intraperitoneal ropivacaine on postoperative pain, and recovery of bowel function and emetic events after laparoscopic herniorrhaphy in toddlers.

METHODS

Seventy-six children aged from 9 months to 3 years were recruited between August 2013 and June 2014 at Tongji Hospital and randomly assigned into two groups. One group received intraperitoneal ropivacaine right before surgery and the control group received intraperitoneal saline. A standard combined general anesthesia procedure was performed under regular monitoring. Postoperative pain was assessed by the FLACC scale. Postoperative analgesic consumption, time to flatus, time to first stool, and postoperative emetic events were also recorded.

RESULTS

When compared with the control group, children who received intraperitoneal ropivacaine experienced less pain 0-4 h after surgery [P < 0.001, difference in median FLACC (95% CI) for 2 h time point is 2.00 (0.87-3.13), for 4 h time point is 1.00 (0.55-1.45)]. In addition, the number of toddlers who received analgesia 0-24 h after surgery in the ropivacaine group was lower than that in the control group [P < 0.001, difference in proportions (95% CI) is 0.575 (0.3865-0.7638)]. Compared with the control group, time to flatus in ropivacaine group was also much shorter [21.1 h vs 16.7 h, P = 0.04, difference in mean (95% CI) is 4.4 (1.49-7.28)], and the time to first stool after surgery was earlier in the ropivacaine group [30.7 h vs 25.6 h, P = 0.003, difference in mean (95% CI) is 5.1 (1.78-8.45)]. Furthermore, the incidence of emetic events in the ropivacaine group was significantly lower than the control group [32.4% vs 11.1%, P = 0.03, difference in proportions (95% CI) is 0.212 (0.0246-0.4002)].

CONCLUSION

The present results indicate that intraperitoneal ropivacaine reduces early postoperative pain and improves recovery after laparoscopic herniorrhaphy in toddlers. Therefore, IPLA is a good stratagem for postoperative pain management after laparoscopic surgery in toddlers.

Cervical zygapophysial (facet) joint pain: effectiveness of interventional management strategies

Diagnostic facet joint nerve blocks have been utilized in the diagnosis of cervical facet joint pain in patients without disk herniation or radicular pain due to a lack of reliable noninvasive diagnostic measures. Therapeutic interventions include intra-articular injections, facet joint nerve blocks and radiofrequency neurotomy. The diagnostic accuracy and effectiveness of facet joint interventions have been assessed in multiple diagnostic accuracy studies, randomized controlled trials (RCTs), and systematic reviews in managing chronic neck pain. This assessment shows there is Level II evidence based on a total of 11 controlled diagnostic accuracy studies for diagnosing cervical facet joint pain in patients without disk herniation or radicular pain utilizing controlled diagnostic blocks. Due to significant variability and internal inconsistency regarding prevalence in a heterogenous population; despite 11 studies, evidence is determined as Level II. Prevalence ranged from 36% to 67% with at least 80% pain relief as the criterion standard with a false-positive rate ranging from 27% to 63%. The evidence is Level II for the long-term effectiveness of radiofrequency neurotomy and facet joint nerve blocks in managing cervical facet joint pain. There is Level III evidence for cervical intra-articular injections.

Effect of electroconvulsive stimulation on messenger RNA expression in the prefrontal cortex in a rat pain model

Previous reports have shown that electroconvulsive therapy (ECT) is efficacious in the treatment of neuropathic pain; however, its mechanism of action remains unclear. The present study aimed to understand these mechanisms by investigating the alterations in the expression of neuropeptide Y (NPY) and interleukin-1β (IL-1β) in the prefrontal cortex. A rat model of neuropathic pain produced by chronic constrictive injury of the sciatic nerve was used, and mechanical and thermal hyperalgesia were evaluated starting 2 days after the injury. Using a pulse generator, ECT was administered to the rodents for 6 days from days 7-12 after the injury. Thermal and mechanical stimulation were administered to assess pain thresholds. Quantitative polymerase chain reaction, used to measure gene expression levels in the prefrontal cortex, showed that NPY and IL-1β gene expression levels in the prefrontal cortex increased following the injury. The present results indicate that these gene expression level variations may be associated with the mechanisms underlying the effect of ECT in treating neuropathic pain.

Do Epidural Injections Provide Short- and Long-term Relief for Lumbar Disc Herniation? A Systematic Review

BACKGROUND

As part of a comprehensive nonsurgical approach, epidural injections often are used in the management of lumbar disc herniation. Recent guidelines and systematic reviews have reached different conclusions about the efficacy of epidural injections in managing lumbar disc herniation.

QUESTIONS/PURPOSES

In this systematic review, we determined the efficacy (pain relief and functional improvement) of the three anatomic approaches (caudal, lumbar interlaminar, and transforaminal) for epidural injections in the treatment of disc herniation.

METHODS

We performed a literature search from 1966 to June 2013 in PubMed, Cochrane library, US National Guideline Clearinghouse, previous systematic reviews, and cross-references for trials studying all types of epidural injections in managing chronic or chronic and subacute lumbar disc herniation. We wanted only randomized controlled trials (RCTs) (either placebo or active controlled) to be included in our analysis, and 66 studies found in our search fulfilled these criteria. We then assessed the methodologic quality of these 66 studies using the Cochrane review criteria for RCTs. Thirty-nine studies were excluded, leaving 23 RCTs of high and moderate methodologic quality for analysis. Evidence for the efficacy of all three approaches for epidural injection under fluoroscopy was strong for short-term (< 6 months) and moderate for long-term (≥ 6 months) based on the Cochrane rating system with five levels of evidence (best evidence synthesis), with strong evidence denoting consistent findings among multiple high-quality RCTs and moderate evidence denoting consistent findings among multiple low-quality RCTs or one high-quality RCT. The primary outcome measure was pain relief, defined as at least 50% improvement in pain or 3-point improvement in pain scores in at least 50% of the patients. The secondary outcome measure was functional improvement, defined as 50% reduction in disability or 30% reduction in the disability scores.

RESULTS

Based on strong evidence for short-term efficacy from multiple high-quality trials and moderate evidence for long-term efficacy from at least one high quality trial, we found that fluoroscopic caudal, lumbar interlaminar, and transforaminal epidural injections were efficacious at managing lumbar disc herniation in terms of pain relief and functional improvement.

CONCLUSIONS

The available evidence suggests that epidural injections performed under fluoroscopy by trained physicians offer improvement in pain and function in well-selected patients with lumbar disc herniation.

Comparison of the efficacy of saline, local anesthetics, and steroids in epidural and facet joint injections for the management of spinal pain: A systematic review of randomized controlled trials

BACKGROUND

The efficacy of epidural and facet joint injections has been assessed utilizing multiple solutions including saline, local anesthetic, steroids, and others. The responses to these various solutions have been variable and have not been systematically assessed with long-term follow-ups.

METHODS

Randomized trials utilizing a true active control design were included. The primary outcome measure was pain relief and the secondary outcome measure was functional improvement. The quality of each individual article was assessed by Cochrane review criteria, as well as the criteria developed by the American Society of Interventional Pain Physicians (ASIPP) for assessing interventional techniques. An evidence analysis was conducted based on the qualitative level of evidence (Level I to IV).

RESULTS

A total of 31 trials met the inclusion criteria. There was Level I evidence that local anesthetic with steroids was effective in managing chronic spinal pain based on multiple high-quality randomized controlled trials. The evidence also showed that local anesthetic with steroids and local anesthetic alone were equally effective except in disc herniation, where the superiority of local anesthetic with steroids was demonstrated over local anesthetic alone.

CONCLUSION

This systematic review showed equal efficacy for local anesthetic with steroids and local anesthetic alone in multiple spinal conditions except for disc herniation where the superiority of local anesthetic with steroids was seen over local anesthetic alone.

Analysis of efficacy differences between caudal and lumbar interlaminar epidural injections in chronic lumbar axial discogenic pain: local anesthetic alone vs. local combined with steroids

STUDY DESIGN

Comparative assessment of randomized controlled trials of caudal and lumbar interlaminar epidural injections in chronic lumbar discogenic pain.

OBJECTIVE

To assess the comparative efficacy of caudal and lumbar interlaminar approaches of epidural injections in managing axial or discogenic low back pain.

SUMMARY OF BACKGROUND DATA

Epidural injections are commonly performed utilizing either a caudal or lumbar interlaminar approach to treat chronic lumbar axial or discogenic pain, which is pain exclusive of that associated with a herniated intervertebral disc, or that is due to degeneration of the zygapophyseal joints, or due to dysfunction of the sacroiliac joints, respectively. The literature on the efficacy of epidural injections in managing chronic axial lumbar pain of presumed discogenic origin is limited.

METHODS

The present analysis is based on 2 randomized controlled trials of chronic axial low back pain not caused by disc herniation, radiculitis, or facet joint pain, utilizing either a caudal or lumbar interlaminar approach, with a total of 240 patients studied, and a 24-month follow-up. Patients were assigned to receive either local anesthetic only or local anesthetic with a steroid in each 60 patient group.

RESULTS

The primary outcome measure was significant improvement, defined as pain relief and functional status improvement of at least 50% from baseline, which was reported at 24-month follow-ups in 72% who received local anesthetic only with a lumbar interlaminar approach and 54% who received local anesthetic only with a caudal approach. In patients receiving local anesthetic with a steroid, the response rate was 67% for those who had a lumbar interlaminar approach and 68% for those who had a caudal approach at 12 months. The response was significantly better in the lumbar interlaminar group who received local anesthetic only, 77% versus 56% at 12 months and 72% versus 54% at 24 months.

CONCLUSION

This assessment shows that in patients with axial or discogenic pain in the lumbar spine after excluding facet joint and SI Joint pain, epidural injections of local anesthetic by the caudal or lumbar interlaminar approach may be effective in managing chronic low back pain with a potential superiority for a lumbar interlaminar approach over a caudal approach.

Systemic ropivacaine diminishes pain sensitization processes: a randomized, double-blinded, placebo-controlled, crossover study in healthy volunteers

Introduction

Ropivacaine is a local anesthetic widely used for regional anesthesia. One of its advantages is low toxicity at plasma concentrations reached systemically during continuous peripheral or central nervous block. The objective of this study was to test the effect of systemic ropivacaine on pain, hyperalgesia, dynamic allodynia, and flare response.

Methods

This randomized, double-blinded, placebo-controlled, crossover study was carried out in at the Clinical Trials Centre, University of Zurich, Switzerland. Twenty healthy male volunteers were included in the study. Exclusion criteria were contraindications or hypersensitivity to local anesthetics, vulnerable subjects (intellectually or mental impaired), drug, alcohol or nicotine abuse, known peripheral neuropathies, diabetes mellitus and/or congestive heart disease. Ropivacaine and saline were infused intravenously during a subcutaneous electrical stimulation. The stimulation software adjusted the stimulus strength according to the rating on a numeric rating scale (NRS; 0–10) maintaining a NRS of 5. Areas of punctate hyperalgesia, dynamic allodynia, and flare response were measured before and after the infusion.

Results

The area of hyperalgesia increased significantly with saline (303 ± 380%, P < 0.05) and ropivacaine (186 ± 137%, P < 0.05). The area of allodynia (253 ± 299%, P < 0.05) and flare response (112 ± 24%, P < 0.05) increased only during the placebo infusion.

Conclusion

The results of this study imply that systemic ropivacaine may diminish pain sensitization processes.

Electronic supplementary material

The online version of this article (doi:10.1007/s40122-013-0021-z) contains supplementary material, which is available to authorized users.

Two-year follow-up results of fluoroscopic cervical epidural injections in chronic axial or discogenic neck pain: a randomized, double-blind, controlled trial

STUDY DESIGN

A randomized, double-blind, active-controlled trial.

OBJECTIVE

To assess the effectiveness of cervical interlaminar epidural injections of local anesthetic with or without steroids for the management of axial or discogenic pain in patients without disc herniation, radiculitis, or facet joint pain.

SUMMARY OF BACKGROUND DATA

Cervical discogenic pain without disc herniation is a common cause of suffering and disability in the adult population. Once conservative management has failed and facet joint pain has been excluded, cervical epidural injections may be considered as a management tool. Despite a paucity of evidence, cervical epidural injections are one of the most commonly performed nonsurgical interventions in the management of chronic axial or disc-related neck pain.

METHODS

One hundred and twenty patients without disc herniation or radiculitis and negative for facet joint pain as determined by means of controlled diagnostic medial branch blocks were randomly assigned to one of the 2 treatment groups. Group I patients received cervical interlaminar epidural injections of local anesthetic (lidocaine 0.5%, 5 mL), whereas Group II patients received 0.5% lidocaine, 4 mL, mixed with 1 mL or 6 mg of nonparticulate betamethasone. The primary outcome measure was ≥ 50% improvement in pain and function. Outcome assessments included numeric rating scale (NRS), Neck Disability Index (NDI), opioid intake, employment, and changes in weight.

RESULTS

Significant pain relief and functional improvement (≥ 50%) was present at the end of 2 years in 73% of patients receiving local anesthetic only and 70% receiving local anesthetic with steroids. In the successful group of patients, however, defined as consistent relief with 2 initial injections of at least 3 weeks, significant improvement was illustrated in 78% in the local anesthetic group and 75% in the local anesthetic with steroid group at the end of 2 years. The results reported at the one-year follow-up were sustained at the 2-year follow-up.

CONCLUSIONS

Cervical interlaminar epidural injections with or without steroids may provide significant improvement in pain and functioning in patients with chronic discogenic or axial pain that is function-limiting and not related to facet joint pain.

Differential expression of rat hippocampal microRNAs in two rat models of chronic pain

The two most common forms of chronic pain are inflammatory pain and neuropathic pain. Nevertheless, the underlying mechanisms of these pain conditions and their therapeutic responses are poorly understood. MicroRNAs (miRNAs) negatively regulate cell genes, and thus control cell proliferation, inflammation and metabolism. In the present study, we examined gene expression in the hippocampus of rats in two models of chronic pain. In addition, we used the left hindpaw procedure to identify differences in the bilateral hippocampus. We divided the rats into the 4 following groups: the group with chronic constriction injury (CCI), the sham-operated group, the group injected with complete Freund's adjuvant (CFA) and the group injected with normal saline. miRNA expression profiles were analyzed using TaqMan low-density array (TLDA). We observed 54 miRNAs (22.7%) in the rats with CCI rats that were differentially expressed, including 7 miRNAs that were downregulated compared with the sham-operated rats. In the CFA-injected rats, 40 miRNAs (16.8%) were differentially expressed, including 8 miRNAs that were downregulated compared with the normal saline-injected rats. Pearson's correlation co-efficient for all detected miRNAs in the rat hippocampus failed to identify differences between the hippocampi bilaterally. An unsupervised cluster analysis produced separate clusters between the control and experimental groups. In this study, we demonstrate the differential expression of hippocampal miRNAs in two rat models of chronic pain; however, no significant differences were observed bilaterally in hippocampal miRNA expression. Further research is required to determine the correlation among miRNAs, messenger RNAs (mRNAs) and proteins.

The role of fluoroscopic interlaminar epidural injections in managing chronic pain of lumbar disc herniation or radiculitis: a randomized, double-blind trial

BACKGROUND

There is continued debate on the effectiveness, indications, and medical necessity of epidural injections in managing pain and disability from lumbar disc herniation, despite extensive utilization. There is paucity of literature on interlaminar epidural injections in managing lumbar disc herniation or radiculitis in contemporary interventional pain management settings utilizing fluoroscopy.

METHODS

A randomized, double-blind, active-control trial was undertaken to assess the effectiveness of lumbar interlaminar epidural injections with or without steroids for disc herniation and radiculitis. The primary outcome was defined as pain relief and functional status improvement of ≥ 50%. One hundred twenty patients were randomly assigned to 1 of the 2 groups. Group I patients received lumbar interlaminar injections containing a local anesthetic (lidocaine 0.5%, 6 mL), whereas Group II patients received lumbar interlaminar epidural injections of 0.5% lidocaine, 5 mL, mixed with 1 mL of non-particulate betamethasone.

RESULTS

In the patients who responded with initial 2 procedures with at least 3 weeks of relief, significant improvement was seen in 80% of the patients in the local anesthetic group and 86% of the patients in the local anesthetic and steroid group. The overall average procedures per year were 3.6 in the local anesthetic group and 4.1 in the local anesthetic and steroid group, with an average relief of 33.7 ± 18.1 weeks in the local anesthetic group and 39.1 ± 12.2 weeks in the local anesthetic and steroid group over a period of 52 weeks in the overall population.

CONCLUSIONS

Lumbar interlaminar epidural injections of local anesthetic with or without steroids might be effective in patients with disc herniation or radiculitis, with potential superiority of steroids compared with local anesthetic alone at 1 year follow-up.

Assessment of effectiveness of percutaneous adhesiolysis and caudal epidural injections in managing post lumbar surgery syndrome: 2-year follow-up of a randomized, controlled trial

Background

The literature is replete with evaluations of failed surgery, illustrating a 9.5%–25% reoperation rate. Speculated causes of post lumbar surgery syndrome include epidural fibrosis, acquired stenosis, recurrent disc herniation, sacroiliac joint pain, and facet joint pain among other causes.

Methods

Patients (n = 120) were randomly assigned to two groups with a 2-year follow-up. Group I (control group, n = 60) received caudal epidural injections with catheterization up to S3 with local anesthetic (lidocaine 2%, 5 mL), nonparticulate betamethasone (6 mg, 1 mL), and 6 mL of 0.9% sodium chloride solution. Group II (intervention group, n = 60) received percutaneous adhesiolysis of the targeted area, with targeted delivery of lidocaine 2% (5 mL), 10% hypertonic sodium chloride solution (6 mL), and nonparticulate betamethasone (6 mg). The multiple outcome measures included the Numeric Rating Scale, the Oswestry Disability Index 2.0, employment status, and opioid intake with assessments at 3, 6, 12, 18, and 24 months posttreatment. Primary outcome was defined as 50% improvement in pain and Oswestry Disability Index scores.

Results

Significant improvement with at least 50% relief with pain and improvement in functional status was illustrated in 82% of patients at the 2-year follow-up in the intervention group compared to 5% in the control group receiving caudal epidural injections. The average number of procedures over a period of 2 years in Group II was 6.4 ± 2.35 with overall total relief of approximately 78 weeks out of 104 weeks.

Conclusion

The results of this study show significant improvement in 82% of patients over a period of 2 years with an average of six to seven procedures of 1-day percutaneous adhesiolysis in patients with failed back surgery syndrome.

Assessment of effectiveness of percutaneous adhesiolysis in managing chronic low back pain secondary to lumbar central spinal canal stenosis

BACKGROUND

Chronic persistent low back and lower extremity pain secondary to central spinal stenosis is common and disabling. Lumbar surgical interventions with decompression or fusion are most commonly performed to manage severe spinal stenosis. However, epidural injections are also frequently performed in managing central spinal stenosis. After failure of epidural steroid injections, the next sequential step is percutaneous adhesiolysis and hypertonic saline neurolysis with a targeted delivery. The literature on the effectiveness of percutaneous adhesiolysis in managing central spinal stenosis after failure of epidural injections has not been widely studied.

STUDY DESIGN

A prospective evaluation.

SETTING

An interventional pain management practice, a specialty referral center, a private practice setting in the United States.

OBJECTIVE

To evaluate the effectiveness of percutaneous epidural adhesiolysis in patients with chronic low back and lower extremity pain with lumbar central spinal stenosis.

METHODS

Seventy patients were recruited. The initial phase of the study was randomized, double-blind with a comparison of percutaneous adhesiolysis with caudal epidural injections. The 25 patients from the adhesiolysis group continued with follow-up, along with 45 additional patients, leading to a total of 70 patients. All patients received percutaneous adhesiolysis and appropriate placement of the Racz catheter, followed by an injection of 5 mL of 2% preservative-free lidocaine with subsequent monitoring in the recovery room. In the recovery room, each patient also received 6 mL of 10% hypertonic sodium chloride solution, and 6 mg of non-particulate betamethasone, followed by an injection of 1 mL of sodium chloride solution and removal of the catheter.

OUTCOMES ASSESSMENT

Multiple outcome measures were utilized including the Numeric Rating Scale (NRS), the Oswestry Disability Index 2.0 (ODI), employment status, and opioid intake with assessment at 3, 6, and 12, 18 and 24 months post treatment. The primary outcome measure was 50% or more improvement in pain scores and ODI scores.

RESULTS

Overall, a primary outcome or significant pain relief and functional status improvement of 50% or more was seen in 71% of patients at the end of 2 years. The overall number of procedures over a period of 2 years were 5.7 ± 2.73.

LIMITATIONS

The lack of a control group and a prospective design.

CONCLUSIONS

Significant relief and functional status improvement as seen in 71% of the 70 patients with percutaneous adhesiolysis utilizing local anesthetic steroids and hypertonic sodium chloride solution may be an effective management strategy in patients with chronic function limiting low back and lower extremity pain with central spinal stenosis after failure of conservatie management and fluoroscopically directed epidural injections.

Fluoroscopic caudal epidural injections in managing chronic axial low back pain without disc herniation, radiculitis, or facet joint pain

Background

Chronic low back pain without disc herniation is common. Various modalities of treatments are utilized in managing this condition, including epidural injections. However, there is continued debate on the effectiveness, indications, and medical necessity of any treatment modality utilized for managing axial or discogenic pain, including epidural injections.

Methods

A randomized, double-blind, actively controlled trial was conducted. The objective was to evaluate the ability to assess the effectiveness of caudal epidural injections of local anesthetic with or without steroids for managing chronic low back pain not caused by disc herniation, radiculitis, facet joints, or sacroiliac joints. A total of 120 patients were randomized to two groups; one group did not receive steroids (group 1) and the other group did (group 2). There were 60 patients in each group. The primary outcome measure was at least 50% improvement in Numeric Rating Scale and Oswestry Disability Index. Secondary outcome measures were employment status and opioid intake. These measures were assessed at 3, 6, 12, 18, and 24 months after treatment.

Results

Significant pain relief and functional status improvement (primary outcome) defined as a 50% or more reduction in scores from baseline, were observed in 54% of patients in group 1 and 60% of patients in group 2 at 24 months. In contrast, 84% of patients in group 1 and 73% in group 2 saw significant pain relief and functional status improvement in the successful groups at 24 months.

Conclusion

Caudal epidural injections of local anesthetic with or without steroids are effective in patients with chronic axial low back pain of discogenic origin without facet joint pain, disc herniation, and/or radiculitis.

Fluoroscopic lumbar interlaminar epidural injections in managing chronic lumbar axial or discogenic pain

Among the multiple causes of chronic low back pain, axial and discogenic pain are common. Various modalities of treatments are utilized in managing discogenic and axial low back pain including epidural injections. However, there is a paucity of evidence regarding the effectiveness, indications, and medical necessity of any treatment modality utilized for managing axial or discogenic pain, including epidural injections. In an interventional pain management practice in the US, a randomized, double-blind, active control trial was conducted. The objective was to assess the effectiveness of lumbar interlaminar epidural injections of local anesthetic with or without steroids for managing chronic low back pain of discogenic origin. However, disc herniation, radiculitis, facet joint pain, or sacroiliac joint pain were excluded. Two groups of patients were studied, with 60 patients in each group receiving either local anesthetic only or local anesthetic mixed with non-particulate betamethasone. Primary outcome measures included the pain relief-assessed by numeric rating scale of pain and functional status assessed by the, Oswestry Disability Index, Secondary outcome measurements included employment status, and opioid intake. Significant improvement or success was defined as at least a 50% decrease in pain and disability. Significant improvement was seen in 77% of the patients in Group I and 67% of the patients in Group II. In the successful groups (those with at least 3 weeks of relief with the first two procedures), the improvement was 84% in Group I and 71% in Group II. For those with chronic function-limiting low back pain refractory to conservative management, it is concluded that lumbar interlaminar epidural injections of local anesthetic with or without steroids may be an effective modality for managing chronic axial or discogenic pain. This treatment appears to be effective for those who have had facet joints as well as sacroiliac joints eliminated as the pain source.

Role of neurotrophins in neuropathic pain

Neurotrophins (NTs) belong to a family of structurally and functionally related proteins, they are the subsets of neurotrophic factors. Neurotrophins are responsible for diverse actions in the developing peripheral and central nervous systems. They are important regulators of neuronal function, affecting neuronal survival and growth. They are able to regulate cell death and survival in development as well as in pathophysiologic states. NTs and their receptors are expressed in areas of the brain that undergo plasticity, indicating that they are able to modulate synaptic plasticity.

Recently, neurotrophins have been shown to play significant roles in the development and transmission of neuropathic pain. Neuropathic pain is initiated by a primary lesion or dysfunction in the nervous system. It has a huge impact on the quality of life. It is debilitating and often has an associated degree of depression that contributes to decreasing human well being. Neuropathic pain ranks at the first place for sanitary costs.

Neuropathic pain treatment is extremely difficult. Several molecular pathways are involved, making it a very complex disease. Excitatory or inhibitory pathways controlling neuropathic pain development show altered gene expression, caused by peripheral nerve injury. At present there are no valid treatments over time and neuropathic pain can be classified as an incurable disease.

Nowadays, pain research is directing towards new molecular methods. By targeting neurotrophin molecules it may be possible to provide better pain control than currently available.

The role of thoracic medial branch blocks in managing chronic mid and upper back pain: a randomized, double-blind, active-control trial with a 2-year followup

Study Design. A randomized, double-blind, active-control trial. Objective. To determine the clinical effectiveness of therapeutic thoracic facet joint nerve blocks with or without steroids in managing chronic mid back and upper back pain. Summary of Background Data. The prevalence of thoracic facet joint pain has been established as 34% to 42%. Multiple therapeutic techniques utilized in managing chronic thoracic pain of facet joint origin include medial branch blocks, radiofrequency neurotomy, and intraarticular injections. Methods. This randomized double-blind active controlled trial was performed in 100 patients with 50 patients in each group who received medial branch blocks with local anesthetic alone or local anesthetic and steroids. Outcome measures included the numeric rating scale (NRS), Oswestry Disability Index (ODI), opioid intake, and work status, at baseline, 3, 6, 12, 18, and 24 months. Results. Significant improvement with significant pain relief and functional status improvement of 50% or more were observed in 80% of the patients in Group I and 84% of the patients in Group II at 2-year followup. Conclusions. Therapeutic medial branch blocks of thoracic facets with or without steroids may provide a management option for chronic function-limiting thoracic pain of facet joint origin.

Fluoroscopic cervical epidural injections in chronic axial or disc-related neck pain without disc herniation, facet joint pain, or radiculitis

Background

While chronic neck pain is a common problem in the adult population, with a typical 12-month prevalence of 30%–50%, there is a lack of consensus regarding its causes and treatment. Despite limited evidence, cervical epidural injections are one of the commonly performed nonsurgical interventions in the management of chronic neck pain.

Methods

A randomized, double-blind, active, controlled trial was conducted to evaluate the effectiveness of cervical interlaminar epidural injections of local anesthetic with or without steroids for the management of chronic neck pain with or without upper extremity pain in patients without disc herniation, radiculitis, or facet joint pain.

Results

One hundred and twenty patients without disc herniation or radiculitis and negative for facet joint pain by means of controlled diagnostic medial branch blocks were randomly assigned to one of two treatment groups, ie, injection of local anesthetic only (group 1) or local anesthetic mixed with nonparticulate betamethasone (group 2). The primary outcome of significant pain relief and improvement in functional status (≥50%) was demonstrated in 72% of group 1 and 68% of group 2. The overall average number of procedures per year was 3.6 in both groups with an average total relief per year of 37–39 weeks in the successful group over a period of 52 weeks.

Conclusion

Cervical interlaminar epidural injections of local anesthetic with or without steroids may be effective in patients with chronic function-limiting discogenic or axial pain.

Management of chronic pain of cervical disc herniation and radiculitis with fluoroscopic cervical interlaminar epidural injections

STUDY DESIGN

A randomized, double-blind, active controlled trial.

OBJECTIVE

To evaluate the effectiveness of cervical interlaminar epidural injections of local anesthetic with or without steroids in the management of chronic neck pain and upper extremity pain in patients with disc herniation and radiculitis.

SUMMARY OF BACKGROUND DATA

Epidural injections in managing chronic neck and upper extremity pain are commonly employed interventions. However, their long-term effectiveness, indications, and medical necessity, of their use and their role in various pathologies responsible for persistent neck and upper extremity pain continue to be debated, even though, neck and upper extremity pain secondary to disc herniation and radiculitis, is described as the common indication. There is also paucity of high quality literature.

METHODS

One-hundred twenty patients were randomly assigned to one of 2 groups: Group I patients received cervical interlaminar epidural injections of local anesthetic (lidocaine 0.5%, 5 mL); Group II patients received 0.5% lidocaine, 4 mL, mixed with 1 mL of nonparticulate betamethasone. Primary outcome measure was ≥ 50 improvement in pain and function. Outcome assessments included Numeric Rating Scale (NRS), Oswestry Disability Index (ODI), opioid intake, employment, and changes in weight.

RESULTS

Significant pain relief and functional status improvement (≥ 50%) was demonstrated in 72% of patients who received local anesthetic only and 68% who received local anesthetic and steroids. In the successful group of participants, significant improvement was illustrated in 77% in local anesthetic group and 82% in local anesthetic with steroid group.

CONCLUSIONS

Cervical interlaminar epidural injections with or without steroids may provide significant improvement in pain and function for patients with cervical disc herniation and radiculitis.

Fluoroscopic caudal epidural injections in managing post lumbar surgery syndrome: two-year results of a randomized, double-blind, active-control trial

STUDY DESIGN

A randomized, active control, double-blind trial.

OBJECTIVE

To evaluate the effectiveness of fluoroscopically directed caudal epidural injections with or without steroids in managing chronic low back and lower extremity pain secondary to post lumbar surgery syndrome.

SUMMARY OF BACKGROUND DATA

There is a paucity of evidence concerning caudal epidural injections for managing chronic persistent low back pain with or without lower extremity pain caused by post lumbar surgery syndrome.

METHODS

This active control randomized study included 140 patients with 70 patients in each group. Group I received 0.5% lidocaine, 10 mL; Group II received 9 mL of 0.5% lidocaine mixed with 1 mL of 6 mg of nonparticulate betamethasone. The multiple outcome measures included the numeric rating scale, the Oswestry Disability Index 2.0, employment status, and opioid intake with assessments at 3, 6, 12, 18, and 24 months posttreatment. Primary outcome was defined as at least 50% improvement in pain and Oswestry Disability Index scores. Patients with a positive response to the first 2 procedures with at least 3 weeks of relief were considered to be successful. All others were considered as failures.

RESULTS

Overall in Group I, 53% and 47% of the patients and in Group II, 59% and 58% of the patients, showed significant improvement with reduction in pain scores and disability index at 12 months and 24 months. In contrast, in the successful groups, significant pain relief and improvement in function were observed in 70% and 62% of Group I at one and 2 years; in 75% and 69% of Group II at one and 2 years. The results in the successful group showed that at the end of the first year patients experienced approximately 38 weeks of relief and at the end of 2 years Group I had 62 weeks and Group II had 68 weeks of relief. Overall total relief for 2 years was 48 weeks in Group I and 54 weeks in Group II. The average procedures in the successful groups were at 4 in one year and 6 at the end of 2 years.

CONCLUSION

Caudal epidural injections of local anesthetic with or without steroid might be effective in patients with chronic persistent low back and/or lower extremity pain in patients with post lumbar surgery syndrome.

A randomized, controlled, double-blind trial of fluoroscopic caudal epidural injections in the treatment of lumbar disc herniation and radiculitis

STUDY DESIGN

A randomized, controlled, double-blind trial.

OBJECTIVE

To assess the effectiveness of fluoroscopically directed caudal epidural injections in managing chronic low back and lower extremity pain in patients with disc herniation and radiculitis with local anesthetic with or without steroids.

SUMMARY OF BACKGROUND DATA

The available literature on the effectiveness of epidural injections in managing chronic low back pain secondary to disc herniation is highly variable.

METHODS

One hundred twenty patients suffering with low back and lower extremity pain with disc herniation and radiculitis were randomized to one of the two groups: group I received caudal epidural injections with an injection of local anesthetic, lidocaine 0.5%, 10 mL; group II patients received caudal epidural injections with 0.5% lidocaine, 9 mL, mixed with 1 mL of steroid. The Numeric Rating Scale (NRS), the Oswestry Disability Index 2.0 (ODI), employment status, and opioid intake were utilized with assessment at 3, 6, and 12 months posttreatment.

RESULTS

The percentage of patients with significant pain relief of 50% or greater and/or improvement in functional status with 50% or more reduction in ODI scores was seen in 70% and 67% in group I and 77% and 75% in group II with average procedures per year of 3.8 ± 1.4 in group I and 3.6 + 1.1 in group II. However, the relief with first and second procedures was significantly higher in the steroid group. The number of injections performed was also higher in local anesthetic group even though overall relief was without any significant difference among the groups. There was no difference among the patients receiving steroids.

CONCLUSION

Caudal epidural injection with local anesthetic with or without steroids might be effective in patients with disc herniation or radiculitis. The present evidence illustrates potential superiority of steroids compared with local anesthetic at 1-year follow-up.

Proteomic analysis of rat brains in a model of neuropathic pain following exposure to electroconvulsive stimulation

Some reports have shown that electroconvulsive shock therapy is effective for treating refractory neuropathic pain. However, its mechanism of action remains unknown. This study analyzes changes in protein expression in the brainstems of neuropathic pain model rats with or without electroconvulsive stimulation (ECS). A neuropathic pain model rat is produced by chronic constrictive injury (CCI) of the sciatic nerve. An ECS was administered to rodents once daily for 6 days after the CCI operation. After ECS, the latency to withdrawal from thermal stimulation was significantly increased. The expression of several proteins was changed after CCI. Ten proteins that increased after CCI then had decreased expression levels (close to control) after ECS, and 8 proteins that decreased after CCI then had increased expression levels (close to control) after ECS. In conclusion, ECS improved thermal hypersensitivity in a rat CCI model. Proteomic analysis showed that altered expression levels of proteins in the brainstem of CCI model rats returned to close to control levels after ECS, including many proteins associated with pain. This trend suggests an association of ECS with improved hypersensitivity, and these results may help elucidate the mechanism of this effect.

Changes in neuropeptide Y gene expression in the spinal cord of chronic constrictive injury model rats after electroconvulsive stimulation

Some reports have shown that electroconvulsive shock therapy (ECT) is effective for treating refractory neuropathic pain. However, its mechanism of action remains unknown. We have previously shown that electroconvulsive shock (ECS) improved thermal hypersensitivity in chronic constrictive injury (CCI) model rats and simultaneously elevated the neuropeptide Y (NPY) expression in the brain of these rats. In this study, we examined changes in the expression of NPY in the spinal cord of a CCI model. The rat model of CCI was established by ligating the left sciatic nerve. ECS was administered to the rats once daily for six days on days 7-12 after the operation using an electrical stimulator. RT-PCR was used to measure NPY mRNA expression in both the right and left L5 dorsal spinal cords on the 14th day after the operation. NPY gene expression was decreased in the dorsal spinal cords after ECS; however, no differences in NPY expression were observed between the right and left side of dorsal spinal cords, suggesting that the effect of changes in NPY expression after ECS on the improvement of neuropathic pain is not directly related to the spinal cord, but mainly to the upper central nerves.

A local anesthetic, ropivacaine, suppresses activated microglia via a nerve growth factor-dependent mechanism and astrocytes via a nerve growth factor-independent mechanism in neuropathic pain

Background

Local anesthetics alleviate neuropathic pain in some cases in clinical practice, and exhibit longer durations of action than those predicted on the basis of the pharmacokinetics of their blocking effects on voltage-dependent sodium channels. Therefore, local anesthetics may contribute to additional mechanisms for reversal of the sensitization of nociceptive pathways that occurs in the neuropathic pain state. In recent years, spinal glial cells, microglia and astrocytes, have been shown to play critical roles in neuropathic pain, but their participation in the analgesic effects of local anesthetics remains largely unknown.

Results

Repetitive epidural administration of ropivacaine reduced the hyperalgesia induced by chronic constrictive injury of the sciatic nerve. Concomitantly with this analgesia, ropivacaine suppressed the increases in the immunoreactivities of CD11b and glial fibrillary acidic protein in the dorsal spinal cord, as markers of activated microglia and astrocytes, respectively. In addition, epidural administration of a TrkA-IgG fusion protein that blocks the action of nerve growth factor (NGF), which was upregulated by ropivacaine in the dorsal root ganglion, prevented the inhibitory effect of ropivacaine on microglia, but not astrocytes. The blockade of NGF action also abolished the analgesic effect of ropivacaine on neuropathic pain.

Conclusions

Ropivacaine provides prolonged analgesia possibly by suppressing microglial activation in an NGF-dependent manner and astrocyte activation in an NGF-independent manner in the dorsal spinal cord. Local anesthetics, including ropivacaine, may represent a new approach for glial cell inhibition and, therefore, therapeutic strategies for neuropathic pain.

Clinical interpretation of pharmacokinetic and pharmacodynamic data in zoologic companion animal species

The treatment and prevention of pain in zoologic companion animals is difficult because of the lack of data available on the safety and efficacy of analgesics. Pharmacokinetic (PK)-pharmacodynamic (PD) studies integrate changes in drug concentrations and changes in the drug's effect. All experimental studies assessing the PDs of analgesics have limitations in animals, but the data provided by experimental studies are valuable in designing dosages. Placebo-controlled, randomized, and blinded clinical trials provide the best PK and PD data, but are rarely performed in major veterinary species because of the number of animals required for the study, lack of preliminary PK and PD data in a given species, species-specific differences in PK and PD, and ethical and toxicologic concerns. The usefulness and limitations as well as considerations for interpreting PK, PD, and controlled clinical studies are discussed. An example of allometric analysis of buprenorphine in mammals is also included.