Yian Chen, MD

Abstract

It is nearly impossible to overestimate the burden of chronic pain, which is associated with enormous personal and socioeconomic costs. Chronic pain is the leading cause of disability in the world, is associated with multiple psychiatric comorbidities, and has been causally linked to the opioid crisis. Access to pain treatment has been called a fundamental human right by numerous organizations. The current COVID-19 pandemic has strained medical resources, creating a dilemma for physicians charged with the responsibility to limit spread of the contagion and to treat the patients they are entrusted to care for.To address these issues, an expert panel was convened that included pain management experts from the military, Veterans Health Administration, and academia. Endorsement from stakeholder societies was sought upon completion of the document within a one-week period.In these guidelines, we provide a framework for pain practitioners and institutions to balance the often-conflicting goals of risk mitigation for health care providers, risk mitigation for patients, conservation of resources, and access to pain management services. Specific issues discussed include general and intervention-specific risk mitigation, patient flow issues and staffing plans, telemedicine options, triaging recommendations, strategies to reduce psychological sequelae in health care providers, and resource utilization.The COVID-19 public health crisis has strained health care systems, creating a conundrum for patients, pain medicine practitioners, hospital leaders, and regulatory officials. Although this document provides a framework for pain management services, systems-wide and individual decisions must take into account clinical considerations, regional health conditions, government and hospital directives, resource availability, and the welfare of health care providers.

View details for DOI 10.1093/pm/pnaa127

View details for PubMedID 32259247

View details for PubMedCentralID PMC7184417

Abstract

Clinical studies frequently report that patients with major mental illness such as schizophrenia and bipolar disorder have co-morbid physical conditions, suggesting that systemic alterations affecting both brain and peripheral tissues might underlie the disorders. Numerous studies have reported elevated levels of anti-Toxoplasma gondii (T. gondii) antibodies in patients with major mental illnesses, but the underlying mechanism was unclear. Using multidisciplinary epidemiological, cell biological, and gene expression profiling approaches, we report here multiple lines of evidence suggesting that a major mental illness-related susceptibility factor, Disrupted in schizophrenia (DISC1), is involved in host immune responses against T. gondii infection. Specifically, our cell biology and gene expression studies have revealed that DISC1 Leu607Phe variation, which changes DISC1 interaction with activating transcription factor 4 (ATF4), modifies gene expression patterns upon T. gondii infection. Our epidemiological data have also shown that DISC1 607 Phe/Phe genotype was associated with higher T. gondii antibody levels in sera. Although further studies are required, our study provides mechanistic insight into one of the few well-replicated serological observations in major mental illness.

View details for DOI 10.1038/s41380-018-0217-z

View details for PubMedID 30127472

View details for PubMedCentralID PMC6382596

Abstract

In addition to basic image-guided injections, there are many advanced procedures to address the challenges of spine pain. Patients with debilitating symptoms are offered relief, a shorter recovery period, and fewer potential complications. Pain arises from numerous sites along the spine, presenting as spine pain or radiculopathy. This article is an overview of advanced techniques in this rapidly progressing field, including neuromodulation, radiofrequency thermocoagulation, discography, intradiscal thermocoagulation, and percutaneous image-guided lumbar decompression; and it highlights etiologic factors and their relationship to therapeutic technique and clinical evidence.

View details for DOI 10.1016/j.nic.2019.07.005

View details for Web of Science ID 000499761100009

View details for PubMedID 31677730

Abstract

Low back pain is the leading cause of worldwide disability, with lumbosacral radiculopathy accounting for over one-third of these cases. There are limited data on the relationship between etiologies and lumbosacral radiculopathy, and it is unknown whether specific causes predict treatment outcomes.This study explores patient-reported etiologies for lumbosacral radiculopathy in a chronic pain clinic between January 2007 and December 2015 and examines whether these causes affected epidural steroid injection outcomes.We reviewed the medical records of 1,242 patients with lumbosacral radiculopathy who received epidural steroid injections. The recording of an inciting event was done contemporaneously based on note templates. A positive outcome following an epidural steroid injection was defined as 30% pain relief sustained for six or more weeks without additional intervention. Factors associated with epidural steroid injection outcome were analyzed by multivariable logistic regression.Fifty point seven percent reported an inciting event, and 59.9% of patients experienced a positive epidural steroid injection outcome. The most commonly reported causes were falls (13.1%), motor vehicle collisions (10.7%), and lifting (7.8%). Individuals with a herniated disc (56.3%) were more likely to report a precipitating cause than those with stenosis (44.7%) or degenerative discs (47.8%, P = 0.012). An inciting event did not predict treatment outcome. Factors associated with negative treatment outcome included opioid consumption (odds ratio [OR] = 0.61, 95% confidence interval [CI] = 0.39-0.95, P = 0.027), secondary gain (OR = 0.69, 95% CI = 0.50-0.96, P = 0.030), and baseline pain score (OR = 0.90, 95% CI = 0.84-0.97, P = 0.006). The number of levels injected was associated with a positive outcome (OR = 2.72, 95% CI = 1.28-6.47, P = 0.008).Reported inciting events are common in patients with lumbosacral radiculopathy but are not associated with outcome following epidural steroid injection, and their occurrence is not always consistent with the purported mechanism of injury.

View details for DOI 10.1093/pm/pnz097

View details for PubMedID 31099846

Abstract

Low back pain is the leading cause of years lost to disability with approximately 15%-25% of the chronic back pain population suffering from lumbar facet arthropathy. No large-scale study has sought to systematically identify inciting events for lumbar facet arthropathy. The aim of this study is to quantify the proportion of individuals with lumbar facetogenic pain who report a specific precipitating event(s) and to determine if there is a correlation between these events and treatment outcome.Institutional electronic medical records were searched based on the current procedural terminology (CPT) codes representing lumbar facet joint radiofrequency ablation for procedures performed between January 2007 and December 2015. All patients had obtained 50% pain relief based on 6-hour pain diaries after 1 or more diagnostic facet blocks. A positive outcome was defined as 50% pain relief sustained for longer than 3-month after procedure, without additional procedural interventions.One thousand sixty-nine people were included in analysis. In the 52% of individuals who described an inciting event, the most commonly reported causes were falls (11%), motor vehicle collisions (11%), sports-related injuries (11%, of which weightlifting accounted for 62%), nonspine postsurgical injuries (2%), and "other" (17%). Six hundred seventeen (57.7%) individuals experienced 50% pain relief sustained for >3 months. Patients whose pain was preceded by an inciting event were more likely to have a positive outcome than those who could not recall a specific precipitating factor (odds ratio, 1.5; confidence interval, 1.02-2.1, P = .01). Another factor associated with outcome was shorter duration of pain (8.1 9.2 vs 9.7 10.1 years, P = .02), with an observed modifier effect of age on outcomes. For a 1-year increase in age, there was a 10% increase in the odds of a positive response.Inciting events are common in patients diagnosed with lumbar facetogenic pain and may be associated with a positive outcome.

View details for DOI 10.1213/ANE.0000000000002242

View details for PubMedID 28704245

Abstract

This review article outlines the recent advances, uses, and adverse effects of cell-based therapy for chronic pain management. Cell based therapies are gaining increasing ground as novel treatment modalities for a variety of pain pathologies that include, but are not limited to, neuropathic pain and degenerative disc disease. As these treatment modalities become more common practice, we have focused our review to provide pain practitioners and other practicing physicians an understanding of the technology and to summarize key clinical data and existing clinical trials that are being pursued by clinical investigators worldwide.Review of stem cell technology and applications in pain management.Narrative review.The Pubmed NCBI and EMBASE databases was utilized to review published reports of clinical studies reported from 2000 to 2015, and ClinicalTrials.gov (www.clinicaltrials.gov/ct2/search) search function was used to document ongoing clinical trials [keywords: "chronic pain," "disc pain," "cell therapy," "osteoarthritis," "neuropathic," "stem cell"] currently active and recruiting patients.Articles were screened by title, abstract, and full article review. They were then analyzed by specific clinical indications and appropriate data were presented based on critical analysis of those articles.More studies looking at the systematic use of stem cells in pain management will be required to draw conclusions about the benefits of the technology.Though the data from existing studies look promising for the use of stem cells as a novel therapeutic strategy for discogenic pain, neuropathic pain, and osteoarthritis, additional clinical studies will be needed to validate the benefit of the technology for clinical use. However, we hope that this narrative review will help guide pain physicians in making informed decisions for their patients about the potential of cell-based therapy for treating chronic pain conditions.

View details for Web of Science ID 000408131300023

View details for PubMedID 28535552

Abstract

Interventional pain treatment centers represent an integral part of interdisciplinary care. Barriers to effective treatment include access to care and financial issues related to pain clinic operations. To address these challenges, specialty clinics have taken steps to identify and remedy missed clinic appointments. However, no prospective study has sought to identify factors associated with pain clinic "no-shows."We performed a prospective, longitudinal year-long study in an inner-city, academic pain clinic in which patients scheduled for office visits and procedures were categorized as to whether they showed up or did not show up for their scheduled appointment without cancelling the day before. Twenty demographic (age, employment status), clinical (eg, diagnosis, duration of pain), and environmental (season, time and day of appointment) variables were assessed for their association with missing an appointment. The logistic regression model predicting no-shows was internally validated with crossvalidation and bootstrapping methods. A predictive nomogram was developed to display effect size of predictors for no-shows.No-show data were collected on 5134 patients out of 5209 total appointments for a capture rate of 98.6%. The overall no-show rate was 24.6% and was higher in individuals who were young (<65 years), single, of ethnic minority background, received Medicare/Medicaid, had a primary diagnosis of low back pain or headaches, were seen on a day with rain or snow or for an initial consult, and had at least 1 previous pain provider. Model discrimination (area under curve) was 0.738 (99% confidence interval, 0.70-0.85). A minimum threshold of 350 points on the nomogram predicted greater than 55% risk of no-shows.We found a high no-show rate, which was associated with predictable and unpredictable (eg, snow) factors. Steps to reduce the no-show rate are discussed. To maximize access to care, operation managers should consider a regression model that accounts for patient-level risk of predictable no-shows. Knowing the patient level, no-show rate can potentially help to optimize the schedule programming by staggering low- versus high-probability no-shows.

View details for DOI 10.1213/ANE.0000000000001794

View details for PubMedID 28277318

Abstract

Coccydynia is a condition with a multitude of different causes, characterized by ill-defined management. There are multiple prospective studies, including several controlled trials, that have evaluated conservative therapies. Additionally, a plethora of observational studies have assessed coccygectomy, but few studies have reported results for nonsurgical interventional procedures. In this report, we describe the treatment results of 12 patients who received conventional or pulsed radiofrequency for coccydynia and systematically review the literature on management.We performed a retrospective data analysis evaluating patients who underwent pulsed or conventional radiofrequency treatment at Johns Hopkins Hospital and Walter Reed National Military Medical Center. A comprehensive literature review was also performed to contextualize these results.The mean age of patients treated was 50.25 years (SD=11.20 years, range = 32-72 years), with the mean duration of symptoms being 3.6 years (SD=3.36 years, range 1-10 years). There were 10 males and two females in this cohort. Among patients who received radiofrequency treatment, the average benefit was 55.5% pain relief (SD=30.33%, range = 0-100%). Those who underwent conventional (vs pulsed radiofrequency) and who received prognostic blocks were more likely to experience a positive outcome. There were two cases of neuritis, which resolved spontaneously after several weeks.Radiofrequency ablation of the sacrococcygeal nerves may serve as a useful treatment option for patients with coccydynia who have failed more conservative measures. Further research into this therapeutic approach and its benefit for coccydynia should incorporate a control group for comparison.

View details for DOI 10.1093/pm/pnw268

View details for PubMedID 28034983

Abstract

Methodologies for generating functional neuronal cells directly from human fibroblasts [induced neuronal (iN) cells] have been recently developed, but the research so far has only focused on technical refinements or recapitulation of known pathological phenotypes. A critical question is whether this novel technology will contribute to elucidation of novel disease mechanisms or evaluation of therapeutic strategies. Here we have addressed this question by studying Tay-Sachs disease, a representative lysosomal storage disease, and Dravet syndrome, a form of severe myoclonic epilepsy in infancy, using human iN cells with feature of immature postmitotic glutamatergic neuronal cells. In Tay-Sachs disease, we have successfully characterized canonical neuronal pathology, massive accumulation of GM2 ganglioside, and demonstrated the suitability of this novel cell culture for future drug screening. In Dravet syndrome, we have identified a novel functional phenotype that was not suggested by studies of classical mouse models and human autopsied brains. Taken together, the present study demonstrates that human iN cells are useful for translational neuroscience research to explore novel disease mechanisms and evaluate therapeutic compounds. In the future, research using human iN cells with well-characterized genomic landscape can be integrated into multidisciplinary patient-oriented research on neuropsychiatric disorders to address novel disease mechanisms and evaluate therapeutic strategies.

View details for DOI 10.2174/1566524015666150303110300

View details for PubMedID 25732146

View details for PubMedCentralID PMC4428755

Abstract

Failed back surgery syndrome (FBSS) is a challenging problem. One treatment advocated to treat FBSS is epidural lysis of adhesions (LOA). The results of studies examining LOA for FBSS have been mixed, but are limited because no study has ever sought to identify factors associated with outcomes.We performed this multicenter, retrospective study in 115 patients who underwent LOA for FBSS (n = 104) or spinal stenosis (n = 11) between 2004 and 2007. Twenty-seven demographic, clinical, and procedural variables were extracted from medical records and correlated with the outcome, defined as 50% pain relief lasting 1 month. Univariable analysis was performed, followed by multivariable logistic regression.Overall, 48.7% (95% confidence interval [CI], 39.3%-58.1%) of patients experienced a positive outcome. In univariable analysis, those who had a positive outcome were older (mean age 64.1 years; 95% CI, 59.7-68.6 vs 57.2; 95% CI, 53.0-61.4 years; P = 0.02), while higher baseline numerical rating scale pain scores were associated with a negative outcome (mean 6.7 years; 95% CI, 6.0-7.3 vs 7.5; 95% CI, 6.9-8.0; P = 0.07). Use of hyaluronidase did not correlate with outcomes in univariable analysis (odds ratio [OR], 1.2; 95% CI, 0.6-2.5; P = 0.65). In multivariable analysis, age 81 years (OR, 7.8; 95% CI, 1.4-53.7), baseline numerical rating scale score 9 (OR, 4.4; 95% CI, 1.4-16.3, P = 0.02), and patients on or seeking disability or worker's compensation (OR, 4.4; 95% CI, 1.1-19.5, P = 0.04) were significantly more likely to experience a positive outcome.Considering our modest success rate, selecting patients for epidural LOA based on demographic and clinical factors may help better select treatment candidates. Procedural factors such as the use of hyaluronidase that increase risks and costs did not improve outcomes, so further research is needed before these become standard practice.

View details for DOI 10.1213/ANE.0000000000000042

View details for PubMedID 24356168

Abstract

Sacroiliac joint (SIJ) pain is an underappreciated source of mechanical low back pain, affecting between 15 and 30% of individuals with chronic, nonradicular pain. Predisposing factors for SIJ pain include true and apparent leg length discrepancy, older age, inflammatory arthritis, previous spine surgery, pregnancy and trauma. Compared with facet-mediated and discogenic low back pain, individuals with SIJ pain are more likely to report a specific inciting event, and experience unilateral pain below L5. Owing in part to its size and heterogeneity, the pain referral patterns of the SIJ are extremely variable. Although no single physical examination or historical feature can reliably identify a painful SIJ, studies suggest that a battery of three or more provocation tests can predict response to diagnostic blocks. Evidence supports both intra- and extra-articular causes for SIJ pain, with clinical studies demonstrating intermediate-term benefit for both intra- and extra-articular steroid injections. In those who fail to experience sustained relief from SIJ injections, radiofrequency denervation may provide significant relief lasting up to 1 year. This review covers all aspects of SIJ pain, with the treatment section being primarily focused on procedural interventions.

View details for DOI 10.1586/ern.12.148

View details for PubMedID 23253394

Abstract

Common variable immunodeficiency (CVID) is the most common primary immune defect, resulting in hypogammaglobulinemia as well as deficits in cell-mediated immunity. Although it mainly manifests in immunodeficiency and related infection, CVID can also be associated with autoimmune phenomena such as immune thrombocytopenic purpura, hemolytic anemia, rheumatoid arthritis, lupus, primary biliary cirrhosis, and autoimmune hepatitis (AIH). AIH is a less common but serious complication of CVID, which can result in early cirrhosis, ascites, and even hepatocellular carcinoma. Here, we discuss a recent case of transplantation for cirrhosis secondary to AIH in the context of CVID. Although the patient's surgery occurred without complication, he rapidly developed fulminant alveolar hemorrhage and seizures, and died secondary to disseminated neuroaspergillosis.

View details for DOI 10.1111/tid.12093

View details for PubMedID 23676145

Abstract

Schizophrenia (SZ) is a psychiatric disease with plausible neurodevelopmental etiology. Although genetic studies show significant association of immune molecules loci such as major histocompatibility complex (MHC) class I with SZ, it is not clear whether these immune molecules are involved in the pathology observed in SZ brains. MHC class I and the classical pathway components of complement system (C1q and C3) have been shown to regulate brain neuronal maturation and function. We have examined the expression of MHC class I and complement protein C3 in two frontal cortical regions of postmortem brains of SZ patients. Since cigarette smoking may modulate MHC class I protein expression and a higher rate of smoking is observed in SZ patients, we studied the expression of MHC class I and C3 in relation to the presence of smoking. We found that MHC class I protein expression is reduced in the dorsolateral prefrontal cortex (DLPFC) but not in the orbitofrontal cortex (OFC) of nonsmoker SZ patients. We did not observe SZ-associated changes in C3 mRNA expression. Our exploratory research suggests a potential involvement of MHC class I in SZ and implies that smoking might modulate its expression.

View details for DOI 10.1016/j.neures.2011.07.1818

View details for PubMedID 21801761