The Effect of Sedation on Diagnostic Lumbar Medial Branch Blocks for Facetogenic Low Back Pain: An Observational Study.

BACKGROUND: Lumbar medial branch blocks (MBB) are some of the most commonly performed pain procedures in the United States. Diagnostic MBBs are performed to confirm if the generator of low back pain is the facet joint. However, with diagnostic injections, false positive blocks may occur. OBJECTIVES:   Our prospective observational study aims to investigate the effects of midazolam sedation on patients' perceived intensity of pain relief following lumbar MBB. STUDY DESIGN: This is a single-center multi-site prospective observational study registered on clinicaltrials.gov (NCT04453449). SETTING: The study was approved by the Henry Ford Health System Institutional Review Board (IRB) in June 2020 (IRB# 14010) and registered on clinicaltrials.gov in July 2020 (NCT04453449). This manuscript adheres to the applicable EQUATOR STROBE guidelines for an observational cohort study. METHODS: Patients that underwent MBB without sedation were compared to sedated patients. Patients were asked to complete the Numeric Rating Scale (NRS) at baseline, one day after their diagnostic blocks, as well as 4 weeks and 8 weeks after their lumbar radiofrequency ablation (RFA). The primary outcome is the difference between baseline NRS pain scores and the lowest reported score in the 8 hours following MBB. For patients who proceed to RFA, the frequency of false positive blocks was evaluated. A patient was considered to have a false positive block when they failed to achieve 50% pain relief from RFA after 2 successful sequential MBBs. RESULTS: There was no significant difference in the NRS pain score change between the sedated and non-sedated groups for diagnostic block one (P = 0.167) and diagnostic block 2 (P = 0.6145). There was no significant difference of false positive rates between non-sedation and sedation patients at 4-weeks post-RFA (P = 0.7178) and at 8-weeks post-RFA (P = 1.000). LIMITATIONS: Some of the limitations of this study include its nonrandomized design, patient self-reported pain scores, as well as the small variability in the injection technique of proceduralists and in the anatomical location of the injection site. CONCLUSIONS: This study showed that midazolam did not change patients' perceived intensity of pain following MBB, as well as false positive rates after RFA. Larger studies are required to draw definitive conclusions.

Artificial Intelligence and Pain Medicine: An Introduction.

Artificial intelligence was introduced 60 years ago and has evolved immensely since that time. While artificial intelligence is found in nearly all aspects of our life, the use of artificial intelligence in the healthcare industry has only recently become apparent and more widely discussed. It is expected that artificial intelligence will allow improved disease recognition, treatment optimization, cost and time savings, product development, decision making, and marketing. For pain medicine specifically, these same benefits will be translatable and we can expect better disease recognition and treatment selection. As adoption occurs with this impressive technology, it will be imperative for the pain medicine community to be informed on proper definitions and expected use cases for artificial intelligence. Our objective was to provide pain medicine physicians an overview of artificial intelligence, including important definitions to aid understanding, and to offer potential clinical applications pertinent to the specialty.

Transcranial magnetic stimulation for the treatment of chronic low back pain: a narrative review.

Background: Chronic low back pain is a debilitating condition that impacts millions of individuals around the world, and also has an enormous economic impact. The impact of chronic pain does not only involve physical health, but can also play a detrimental role in a patient's mental health. Consequently, it is critical to approach these patients with multimodal management. Initially, a treatment plan which includes medications, psychotherapy, physical therapy, and invasive interventions can be utilized for chronic back pain. However, many patients experience refractory low back pain to these initial treatments, which can result in non-resolving chronic pain. As a result, many new interventions have been developed in recent years to treat refractory low back pain, including non-invasive transcranial magnetic stimulation. In recent years, there has been some limited and preliminary evidence for the treatment of chronic low back pain with transcranial magnetic stimulation, as further investigation on this intervention is warranted. After reviewing analytically high impact studies, our objective is to provide a narrative review of the treatment of chronic low back pain with repetitive transcranial magnetic stimulation (rTMS). Methods: We performed a comprehensive database search on PubMed, Embase, PsychInfo, Web of Science, and CINAHL for literature that pertains to the treatment of chronic low back pain with transcranial magnetic stimulation using these terms: "Chronic Low Back Pain and Transcranial Magnetic Stimulation", "Low Back Pain and Transcranial Magnetic Stimulation", "Chronic Back Pain and Transcranial Magnetic Stimulation", "Chronic Low Back Pain and TMS", "Low Back Pain and TMS", and "Chronic Back Pain and TMS". We aim to provide a narrative review of the role of rTMS in CLBP. Results: Initial search results from September to November 2021 using the above-mentioned search criteria included 458 articles, of which 164 duplicates were removed and 280 were further excluded by a three-person (CO, NM and RA) screening process. Articles were further filtered based on various exclusion and inclusion criteria. The resulting 6 studies are discussed. Discussion: The studies reviewed suggest the potential benefit in chronic lower back pain symptoms after various rTMS protocols and sites of stimulation. However, the included studies are not without issues in design for example: not randomized, not blinded, or have small sample size. This review highlights the need for scaled, better controlled research studies and standardization of treatment protocols to determine if rTMS for chronic lower back pain will be accepted as a standard treatment option for patients with chronic lower back pain symptoms.

Preoperative hemoglobin A1c and perioperative blood glucose in patients with diabetes mellitus undergoing spinal cord stimulation surgery: A literature review of surgical site infection risk.

AIMS: The aim of our study was to review the surgical literature regarding the relationship between hemoglobin A1c (HbA1c), diagnosis of diabetes mellitus (DM), and risk of postoperative surgical site infection (SSI). METHODS: A librarian-assisted literature search was performed with two goals: (1) identify surgical publications related to SSI and HbA1c values, and (2) identify publications reporting infection risk with DM in spinal cord stimulation (SCS), intrathecal drug delivery systems (IDDS), and cardiovascular implantable electronic device (CIED) implantation surgeries. Published guidelines on perioperative management of DM are reviewed. RESULTS: We identified 30 studies reporting SSI and HbA1c values. The literature review indicated that for many surgical procedures, elevated HbA1c is not correlated to rate of SSI. We identified 16 studies reporting infection rates within DM cohorts following SCS, IDDS, and CIED implantation surgeries. The data reviewed did not indicate DM as an independent risk factor for SSI. CONCLUSION: Preoperative HbA1c levels in patients with a history of DM is not a singularly sufficient tool to estimate risk of perioperative infection in SCS implantation surgery. Published guidelines on perioperative management of DM do not suggest a specific HbA1c above which surgery should be delayed; intentional perioperative glycemic control is recommended.

The American Society of Pain and Neuroscience (ASPN) Evidence-Based Clinical Guideline of Interventional Treatments for Low Back Pain.

Introduction: Painful lumbar spinal disorders represent a leading cause of disability in the US and worldwide. Interventional treatments for lumbar disorders are an effective treatment for the pain and disability from low back pain. Although many established and emerging interventional procedures are currently available, there exists a need for a defined guideline for their appropriateness, effectiveness, and safety. Objective: The ASPN Back Guideline was developed to provide clinicians the most comprehensive review of interventional treatments for lower back disorders. Clinicians should utilize the ASPN Back Guideline to evaluate the quality of the literature, safety, and efficacy of interventional treatments for lower back disorders. Methods: The American Society of Pain and Neuroscience (ASPN) identified an educational need for a comprehensive clinical guideline to provide evidence-based recommendations. Experts from the fields of Anesthesiology, Physiatry, Neurology, Neurosurgery, Radiology, and Pain Psychology developed the ASPN Back Guideline. The world literature in English was searched using Medline, EMBASE, Cochrane CENTRAL, BioMed Central, Web of Science, Google Scholar, PubMed, Current Contents Connect, Scopus, and meeting abstracts to identify and compile the evidence (per section) for back-related pain. Search words were selected based upon the section represented. Identified peer-reviewed literature was critiqued using United States Preventive Services Task Force (USPSTF) criteria and consensus points are presented. Results: After a comprehensive review and analysis of the available evidence, the ASPN Back Guideline group was able to rate the literature and provide therapy grades to each of the most commonly available interventional treatments for low back pain. Conclusion: The ASPN Back Guideline represents the first comprehensive analysis and grading of the existing and emerging interventional treatments available for low back pain. This will be a living document which will be periodically updated to the current standard of care based on the available evidence within peer-reviewed literature.

Balloon Kyphoplasty vs Vertebroplasty: A Systematic Review of Height Restoration in Osteoporotic Vertebral Compression Fractures.

Purpose of Review: This systematic review comprehensively compared balloon kyphoplasty and vertebroplasty with respect to height restoration and pain relief. Recent Findings: PRISMA guidelines were utilized to compare balloon kyphoplasty and vertebroplasty, focusing on the primary outcome of height restoration and the secondary outcomes of pain relief and functionality. A total of 33 randomized controlled trials were included; 20 reviewed balloon kyphoplasty, 7 reviewed vertebroplasty, and 6 compared vertebroplasty to balloon kyphoplasty. Both treatments restored some vertebral body height and showed benefits in pain reduction and improved patient-reported functionality. Summary: Balloon kyphoplasty and vertebroplasty are effective treatments for vertebral compression fractures and this review suggests that balloon kyphoplasty may be favored for vertebral height restoration. Further studies are needed to conclude whether balloon kyphoplasty or vertebroplasty is superior for alleviating pain.

Cervical spine ligamentum flavum gaps: MR characterisation and implications for interlaminar epidural injection therapy.

BACKGROUND: Cervical epidural steroid injections are commonly performed to manage pain from cervical spine disease. Cadaveric studies have demonstrated incomplete ligamentum flavum fusion in the central interlaminar region with resultant midline gaps. We performed an MR-based characterization of cervical ligamentum flavum midline gaps to improve understanding of their prevalence and guide interventionalists in procedural planning. METHODS: Fifty patients were retrospectively reviewed following institutional review board approval. Axial T2-weighted spinecho sequences were used to evaluate ligamentum flavum integrity at the interlaminar spaces of C5-C6, C6-C7 and C7-T1. Interlaminar spaces were further subdivided into superior, middle, and inferior portions, yielding 150 interlaminar regions characterized from C5 to T1. Subsequently, a novel categorization of gap morphology was performed, highlighting gap morphology (anterior, posterior, full, or no gap). RESULTS: Full gaps of the ligamentum flavum, with direct epidural space exposure, were observed with variable prevalence at all three levels evaluated. The highest incidence of full ligamentum flavum gaps were observed at C7-T1, occurring in 71.4% of patients at both its middle and inferior portions. The inferior aspect of C5-C6 demonstrated the lowest observed rates of full ligamentum flavum gap (2%). CONCLUSIONS: Ligamentum flavum gaps occur in the lower cervical spine at high rates, with the highest prevalence of full thickness ligamentum flavum gaps at C7-T1. Interventionists must be aware of these important normal variants and evaluate preprocedural MRI to plan interventions.

A systematic review of full endoscopic versus micro-endoscopic or open discectomy for lumbar disc herniation.

Aim: Endoscopic discectomies provide several advantages over other techniques such as traditional open lumbar discectomy (OLD) including possibly decreased complications, shorter hospital stay and an earlier return to work. Methods: An electronic database search including MEDLINE/PubMed, EMBASE, Scopus, Cochrane Database of Systematic Reviews and Cochrane Controlled trials (CENTRAL) were reviewed for randomized controlled trials (RCTs) only. Results: A total of nine RCTs met inclusion criteria. Three showed benefit of endoscopic discectomy over the comparator with regards to pain relief, with the remaining six studies showing no difference in pain relief or function. Conclusion: Based on review of the nine included studies, we can conclude that endoscopic discectomy is as effective as other surgical techniques, and has additional benefits of lower complication rate and superior perioperative parameters.

Lay abstract This systematic review investigates the use of a common surgical procedure, endoscopic discectomy, for the surgical treatment of lumbar disc herniation. It is a type of minimally invasive spine surgery (MISS) procedure, which has been shown to be not only effective in outcomes, but also optimal for peri-operative parameters, such as post-operative hospital stay, time duration of surgery and blood loss during the procedure. We utilized five search databases to collect data on only randomized controlled studies that investigated endoscopic discectomy compared with another surgical technique. Our results include nine randomized controlled trials, three of which showed improvement in pain scores for endoscopic discectomies. Consequently, in combination with the optimal peri-operative measures, it is concluded that endoscopic discectomy is a reasonable procedure to treat lumbar disc herniation surgically.

Slipping rib syndrome: case report of an iatrogenic result following video-assisted thoracic surgery and chest tube placement.

The aim of this case report is to shed light on slipping rib syndrome (SRS), a painful and overlooked condition. A 62-year old man reported intermittent, self-resolving sharp rib pain that began after a video-assisted thoracic surgery and chest tube placement 4 years prior to presentation. The patient's pain was associated with a rigid protrusion in the right upper quadrant, and home use of acetaminophen provided no relief. After physical examination, multiple imaging and lab tests, the patient was diagnosed with SRS and was referred to physical therapy and thoracic surgery for further evaluation. SRS is an under-recognized cause of upper abdominal and lower thoracic pain that should be considered if a patient's history includes previous trauma or abdominal surgery.

Lay abstract This is a case report of slipping rib syndrome (SRS). It is a painful medical condition. A 62-year old man after a video-assisted thoracic surgery and chest tube placement had recurrent, self-resolving sharp rib pain. The pain was associated with a rigid lump in the right lower rib cage. Acetaminophen and narcotics provided no relief. After physical examination, multiple imaging and lab tests, he was diagnosed with SRS and was referred to physical therapy and thoracic surgery for further evaluation. SRS is an under-recognized cause of rib pain that should be considered if a patient's history includes previous trauma or abdominal surgery.

Treatment of knee osteoarthritic pain with platelet-rich plasma: a systematic review of clinical studies.

Introduction: Knee osteoarthritis is a degenerative joint disease that is secondary to degradation of articular cartilage, reformation of subchondral bone through degradation and proliferation as well as presence of synovitis. Materials & methods: This systematic review was conducted and reported as per Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Results: A total of 30 of the 48 comparators showed statistically significant superiority with platelet-rich plasma (PRP) compared with a control, while the other 16 comparators showed no significant difference between PRP and the comparator. Conclusion: We can only recommend PRP for patients with early-stage osteoarthritis (I or II) and who are aged below 65, based on our findings. Based on the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) recommendations, while studies reviewed were randomized controlled studies, and therefore, high grade, due to variance in imprecision, risk of bias and inconsistency among the 37 studies, it would be reasonable to rate this paper as subjectively moderate.

A Systematic Literature Review of Peripheral Nerve Stimulation Therapies for the Treatment of Pain.

OBJECTIVE: To conduct a systematic literature review of peripheral nerve stimulation (PNS) for pain. DESIGN: Grade the evidence for PNS. METHODS: An international interdisciplinary work group conducted a literature search for PNS. Abstracts were reviewed to select studies for grading. Inclusion/exclusion criteria included prospective randomized controlled trials (RCTs) with meaningful clinical outcomes that were not part of a larger or previously reported group. Excluded studies were retrospective, had less than two months of follow-up, or existed only as abstracts. Full studies were graded by two independent reviewers using the modified Interventional Pain Management Techniques-Quality Appraisal of Reliability and Risk of Bias Assessment, the Cochrane Collaborations Risk of Bias assessment, and the US Preventative Services Task Force level-of-evidence criteria. RESULTS: Peripheral nerve stimulation was studied in 14 RCTs for a variety of painful conditions (headache, shoulder, pelvic, back, extremity, and trunk pain). Moderate to strong evidence supported the use of PNS to treat pain. CONCLUSION: Peripheral nerve stimulation has moderate/strong evidence. Additional prospective trials could further refine appropriate populations and pain diagnoses.

A Systematic Literature Review of Dorsal Root Ganglion Neurostimulation for the Treatment of Pain.

OBJECTIVE: To conduct a systematic literature review of dorsal root ganglion (DRG) stimulation for pain. DESIGN: Grade the evidence for DRG stimulation. METHODS: An international, interdisciplinary work group conducted a literature search for DRG stimulation. Abstracts were reviewed to select studies for grading. General inclusion criteria were prospective trials (randomized controlled trials and observational studies) that were not part of a larger or previously reported group. Excluded studies were retrospective, too small, or existed only as abstracts. Studies were graded using the modified Interventional Pain Management Techniques-Quality Appraisal of Reliability and Risk of Bias Assessment, the Cochrane Collaborations Risk of Bias assessment, and the US Preventative Services Task Force level-of-evidence criteria. RESULTS: DRG stimulation has Level II evidence (moderate) based upon one high-quality pivotal randomized controlled trial and two lower-quality studies. CONCLUSIONS: Moderate-level evidence supports DRG stimulation for treating chronic focal neuropathic pain and complex regional pain syndrome.

The Regenerative Potential of Therapeutic Ultrasound on Neural Tissue: A Pragmatic Review.

OBJECTIVES: Low-intensity ultrasound (LIU)/low-intensity pulsed ultrasound (LIPUS) may influence nerve tissue regeneration and axonal changes in the context of carpal tunnel syndrome (CTS) and in the animal model. The purpose of this pragmatic review is to understand the current knowledge for the effects of low-intensity therapeutic ultrasound in the animal and human model and determine the future directions of this novel field. DESIGN: Pragmatic review. METHODS: We performed a literature search of available material using OVID, EmBase, and PubMed for LIU/LIPUS, all of which were preclinical trials, case reports, and case series using animal models. For CTS, a literature search was performed on PubMed (1954 to 2019), CENTRAL (the Cochrane Library, 1970 to 2018), Web of Science (1954 to 2019), and SCOPUS (1954 to 2019) to retrieve randomized controlled trials. RESULTS: Eight articles were discussed showing the potential effects of LIU on nerve regeneration in the animal model. Each of these trials demonstrated evidence of nerve regeneration in the animal model using LIPUS or LIU. Seven randomized controlled trials were reviewed for ultrasound effects for the treatment of carpal tunnel syndrome, each showing clinical efficacy comparable to other treatment modalities. CONCLUSIONS: LIU/LIPUS is a promising and noninvasive means of facilitating nerve regeneration in the animal model and in the treatment of carpal tunnel syndrome. Although many of the trials included in this review are preclinical, each demonstrates promising outcomes that could eventually be extrapolated into human studies.

A Systematic Literature Review of Spine Neurostimulation Therapies for the Treatment of Pain.

OBJECTIVE: To conduct a systematic literature review of spinal cord stimulation (SCS) for pain. DESIGN: Grade the evidence for SCS. METHODS: An international, interdisciplinary work group conducted literature searches, reviewed abstracts, and selected studies for grading. Inclusion/exclusion criteria included randomized controlled trials (RCTs) of patients with intractable pain of greater than one year's duration. Full studies were graded by two independent reviewers. Excluded studies were retrospective, had small numbers of subjects, or existed only as abstracts. Studies were graded using the modified Interventional Pain Management Techniques-Quality Appraisal of Reliability and Risk of Bias Assessment, the Cochrane Collaborations Risk of Bias assessment, and the US Preventative Services Task Force level-of-evidence criteria. RESULTS: SCS has Level 1 evidence (strong) for axial back/lumbar radiculopathy or neuralgia (five high-quality RCTs) and complex regional pain syndrome (one high-quality RCT). CONCLUSIONS: High-level evidence supports SCS for treating chronic pain and complex regional pain syndrome. For patients with failed back surgery syndrome, SCS was more effective than reoperation or medical management. New stimulation waveforms and frequencies may provide a greater likelihood of pain relief compared with conventional SCS for patients with axial back pain, with or without radicular pain.

Therapeutic Ultrasound for Pain Management in Chronic Low Back Pain and Chronic Neck Pain: A Systematic Review.

BACKGROUND: Low back pain (LBP) and neck pain are major causes of pain and disability that are experienced across all ages. The primary goals of treatment are to improve patient function and facilitate a return to the patient's desired level of daily activity. Therapeutic ultrasound is a noninvasive modality widely utilized in the management of musculoskeletal disorders, but there continues to be controversy regarding its use due to insufficient evidence of effectiveness. The objective of this systematic review was to evaluate the effectiveness of therapeutic ultrasound in the management of patients with chronic LBP and neck pain. METHODS: Using PRISMA guidelines, a search of the PubMed and CENTRAL (The Cochrane Library) databases was performed to retrieve randomized controlled trials (RCTs) that evaluated therapeutic ultrasound in patients with chronic LBP or neck pain. RESULTS: The search strategy identified 10 trials that met the criteria for inclusion. Three studies in LBP reported that both therapeutic and sham (placebo) ultrasound provided significant improvement in pain intensity. In each of these studies, ultrasound was found to be more effective than placebo when using only one of several validated instruments to measure pain. Three of the four studies on neck pain demonstrated significant pain relief with ultrasound in combination with other treatment modalities. However, only one of these studies demonstrated that the use of ultrasound was the cause of the statistically significant improvement in pain intensity. CONCLUSIONS: Therapeutic ultrasound is frequently used in the treatment of LBP and neck pain and is often combined with other physiotherapeutic modalities. However, given the paucity of trials and conflicting results, we cannot recommend the use of monotherapeutic ultrasound for chronic LBP or neck pain. It does seem that ultrasound may be considered as part of a physical modality treatment plan that may be potentially helpful for short-term pain relief; however, it is undetermined which modality may be superior. In both pain syndromes, further trials are needed to define the true effect of low-intensity ultrasound therapy for axial back pain. No conclusive recommendations may be made for optimal settings or session duration.

Therapeutic Ultrasound for Chronic Pain Management in Joints: A Systematic Review.

BACKGROUND: Treatments for joint pain and dysfunction focus on restoration of joint motion, improvement in pain and a return to the previous level of the patient's daily activity. Therapeutic ultrasound is a noninvasive modality widely utilized in the management of musculoskeletal disorders. The objective of this systematic review was to evaluate the effectiveness of therapeutic ultrasound in the management of patients with knee, shoulder and hip pain. METHODS: Using PRISMA guidelines, a search of the PubMed, CENTRAL (The Cochrane Library), Web of Science and Scopus databases was performed to retrieve randomized controlled trials (RCTs) that evaluated therapeutic ultrasound (continuous and pulsed) in patients with chronic knee, shoulder and hip pain. RESULTS: The search strategy identified 8 trials for knee, 7 trials for shoulder and 0 trials for hip that met the criteria for inclusion. All 8 trials showed improvement in knee pain, and of these studies 3 showed statistical significance improvement for therapeutic ultrasound versus the comparator. For shoulder pain, all 7 trials showed reduction in pain, but should be noted that 4 of studies demonstrated that therapeutic ultrasound is inferior to the comparator modality. CONCLUSION: Therapeutic ultrasound is frequently used in the treatment of knee, shoulder and hip pain and is often combined with other physiotherapeutic modalities. The literature on knee arthritis is most robust, with some evidence supporting therapeutic ultrasound, though the delivery method of ultrasound (pulsed vs continuous) is controversial. As a monotherapy, ultrasound treatment may not have a significant impact on functional improvement but can be a reasonable adjunct to consider with other common modalities. In all three pain syndromes, especially for hip pain, further trials are needed to define the true effect of low-intensity ultrasound therapy knee, shoulder and hip pain. No conclusive recommendations may be made for optimal settings or session duration.

Incidence and risk factors for development of persistent postsurgical pain following total knee arthroplasty: A retrospective cohort study.

Persistent postsurgical pain (PPP) is defined as the discomfort that lasts >3 months postoperatively. The primary aim of this retrospective study was to estimate the risk of developing moderate-to-severe PPP after primary total knee arthroplasty (TKA). The secondary goal was to explore potential predictors of this outcome.Data were collected via hospital arthroplasty registry and chart review. The risk of moderate-to-severe PPP, defined as ≥4 on the numerical rating scale (NRS) at minimum of 3 months post-surgery, was calculated. Multivariable logistic regression was used to estimate the association of patient demographics, diagnoses, length of hospital stay, and preoperative NRS with the odds of developing PPP. Exploratory, simple logistic regression was used to estimate the association of perioperative factors with the odds of developing PPP on a subset of patients (n = 72).The risk of PPP after TKA was 31.3% (95% confidence interval [CI]: 27.5-35.0) (n = 578). Every 2-point increase in baseline NRS was associated with 1.66 (95% CI: 1.37-2.03) times the odds of developing PPP (P < .001). African-Americans (vs whites) had 1.82 (95% CI: 1.03-3.22) times the odds of developing PPP (P = .040). Exploratory analysis suggested that the adductor canal saphenous nerve (vs femoral nerve) blocks were associated with 2.87 (95% CI: 1.00-8.26) times the odds of developing PPP (P = .049).This study estimated a high risk (31.3%) of moderate-to-severe PPP after primary TKA. This study suggested that higher preoperative pain scores might be associated with greater odds of developing PPP. Moreover, this study suggested the possibility that racial differences and types of peripheral nerve blocks might be associated with greater odds of developing moderate-to-severe PPP after TKA surgery. However, the evidence obtained from our exploratory analysis of limited data certainly requires further exploration in large-scale studies.

Nonopioid versus opioid agents for chronic neuropathic pain, rheumatoid arthritis pain, cancer pain and low back pain.

Chronic pain continues to be a major health issue throughout the world and a huge economic burden for nations around the world. While the use of opioids does have risks, they are still widely used by clinicians as a treatment option for various chronic pain conditions. This review explores and compares the efficacy and safety of opioid and nonopioid agents for the following commonly encountered chronic pain conditions: neuropathic pain, rheumatoid arthritis joint pain, cancer pain and low back pain. Our findings demonstrate that while there are several nonopioid pharmacologic options that are clinically effective, opioids maintain a role in the treatment of certain chronic pain conditions and should continue to have an important place in the armamentarium of clinicians.

Extrapyramidal signs occurring after sympathetic block for complex regional pain syndrome responding to diphenhydramine: Two case reports.

RATIONALE: To present an unusual extrapyramidal motor response occurring after a sympathetic block in CRPS and its successful treatment with diphenhydramine. PATIENT CONCERNS: Severe pain related to Complex Regional Pain Syndrome type 1 interfering with activities of daily living. DIAGNOSES: Complex Regional Pain Syndrome type 1. INTERVENTIONS: We report a video case reports of two patients with a diagnosis of CRPS type-I. Both patients exhibited similar presentation of unusual extrapyramidal motor response of the affected limb following lumbar sympathetic block. Both patients were treated with intravenous diphenhydramine to abort the extrapyramidal motor response. OUTCOMES: Both patients similarly responded to treatment with intravenous diphenhydramine with abrupt resolution of the motor response. LESSONS: Sympathetic blockade may interfere with the adaptive autonomic reflex circuits of the motor balance homeostasis in patients with complex regional pain syndrome. Disinhibition of extrapyramidal system may lead to immediate expression of extrapyramidal signs following the sympathetic block. Diphenhydramine, with its anti-histaminic and anticholinergic properties, may be effective in aborting such extrapyramidal signs, and should be considered as a treatment option in similar cases.