Opioids for low back pain

Evaluating associations between social risks and health care utilization in patients with chronic low back pain

Introduction

Care and outcomes for patients with chronic low back pain (cLBP) are influenced by the social risk factors that they experience. Social risk factors such as food insecurity and housing instability have detrimental effects on patient health and wellness, healthcare outcomes, and health disparities.

Objectives

This retrospective cross-sectional study examined how social risk factors identified in unstructured and structured electronic health record (EHR) data for 1,295 patients with cLBP were associated with health care utilization. We also studied the impact of social risk factors, controlling for back pain-related disability on health care utilization.

Methods

Included patients who received outpatient spine and/or physical therapy services at an urban academic medical center between 2018 and 2020. Five identified social risks were financial insecurity, housing instability, food insecurity, transportation barriers, and social isolation. Outcomes included 4 categories of health care utilization: emergency department (ED) visits/hospitalizations, imaging, outpatient specialty visits related to spine care, and physical therapy (PT) visits. Poisson regression models tested associations between the presence of identified social risks and each outcome measure.

Results

Identified social risks in 12.8% of the study population (N = 166/1,295). In multivariate models, social isolation was positively associated with imaging, specialty visits, and PT visits; housing instability was positively associated with ED visits/hospitalizations and imaging; food insecurity was positively associated with ED visits/hospitalizations and specialty visits but negatively associated with PT visits; and financial strain was positively associated with PT visits but negatively associated with ED visits/hospitalization.

Conclusion

These associations were seen above and beyond other factors used as markers of socioeconomic marginalization, including neighborhood-level social determinants of health, race/ethnicity, and insurance type. Identifying and intervening on social risk factors that patients with cLBP experience may improve outcomes and be cost-saving.

Factors associated with pain-related functional interference in people with chronic low back pain enrolled in a physical exercise programme: the role of pain, sleep, and quality of life

OBJECTIVE

To identify the factors associated with the pain-related functional interference level in people with chronic low back pain.

DESIGN

Cross-sectional.

SUBJECTS/PATIENTS

Chronic low back pain patients.

METHODS

Sociodemographic data, pain intensity, pain-related functional interference, physical functioning and fitness, sleep quality, anxiety and depression, social support, and health-related quality of life were recorded. Descriptive and bivariate analyses were performed. A linear regression model was carried out to identify the factors associated with the pain-related functional interference level.

RESULTS

99 participants were involved (mean age: 54.37 SD: 12.44; women: 67.7%). 37.4%, 27.3%, and 35.4% were classified into low, moderate, and high pain-related functional interference level groups, respectively. Higher pain-related functional interference was associated with higher pain intensity (β: 0.724; p = 0.026), worse sleep quality (β: 0.077; p = 0.012), worse quality of life (physical (β: -0.539; p < 0.001) and mental (β: -0.289; p < 0.001), and lower consumption of weak opioids (β: -3.408; p = 0.037).

CONCLUSION

Beyond the pain experience and intensity among people with chronic low back pain, several biopsychosocial factors associated with this condition has been identified. Furthermore, higher pain intensity, worse sleep quality, worse quality of life, and weak opioids' consumption have been related to the pain-related functional interference of this population.

Safety and efficacy of long-term use of a buprenorphine transdermal patch system in patients with osteoarthritis and low back pain refractory to non-opioid analgesics: Post-marketing surveillance of 3000 cases

OBJECTIVES

A post-marketing surveillance was conducted to evaluate the safety and efficacy of the buprenorphine transdermal patch under actual clinical practice.

RESULTS

Of the 3017 patients included in the safety analysis, adverse drug reactions (ADRs) were observed in 1524 (50.5%), the most common being nausea, skin symptoms at the site of application, constipation, and vomiting. The incidences of respiratory depression and withdrawal symptoms were low, and no drug dependence was observed. Among the 2573 patients included in the efficacy analysis, the efficacy (≥2-point improvement in the numerical rating scale) rate was 74.4%, which was significantly higher in older adults (≥65 y.o) than in younger adults. Discontinuation was mostly caused by ADRs during the early initiation phase.

CONCLUSION

This study demonstrated the safety and efficacy of long-term administration of buprenorphine transdermal patches, suggesting that pain control is possible over the long term if attention is paid to ADRs in the early stages of administration.

Human molecular mechanisms of discogenic low back pain: A scoping review

The limited understanding of the mechanisms underlying human discogenic low back pain (DLBP) has hampered the development of effective treatments. While there is much research on disc degeneration, the association between degeneration and pain is weak. Therefore, there is an urgent need to identify pain-inducing molecular mechanism to facilitate the development of mechanism-specific therapeutics. This scoping review aims to determine the current knowledge of molecular mechanisms associated with human DLBP. A systematic search on CENTRAL, CINAHL, Citation searching, ClinicalTrials.gov, Embase, Google Scholar, MEDLINE, PsycINFO, PubMed, Scopus, Web of Science, and World Health Organization was performed. Studies with human DLBP as diagnosed by discography or imaging that analyzed human disc tissues and reported pain-related outcomes were included, and those on predominant radicular pain were excluded. The search returned 6012 studies. Most studies did not collect pain-related outcomes. Those that included pain assessment relied on self-report of pain intensity and disability. Six studies qualified for data extraction and synthesis. The main molecular mechanisms associated with DLBP were the expressions of nociceptive neuropeptides and cytokines, particularly TNF-αdue to its strong association with pain outcomes. Activation of NF-κB signaling pathway, alterations in adrenoceptor expressions, and increase in reactive oxygen species (ROS) were also associated with DLBP through regulation of pro-inflammatory factors and pain-related neuropeptides. Current evidence converges to TNF-α, NF-κB signaling, and ROS-induced pro-inflammation. Major weaknesses in the current literature are the focus on degeneration without pain phenotyping, and lack of association of molecular findings with pain outcomes. PERSPECTIVE: This scoping review identified TNF-α, NF-κB signaling, and ROS-induced pro-inflammation as relevant mechanisms of human discogenic low back pain. Major weaknesses in the current literature are the focus on degeneration without pain phenotyping, and lack of association of molecular findings with pain outcomes.

Pain Resilience and Coping Behaviors in Individuals in a Collectivist Social Context

BACKGROUND/OBJECTIVES

Pain resilience (PR) may be associated with different coping skills, resulting in differences in pain outcomes. This study aimed to understand the role of PR in dictating the choice of coping methods.

METHODS

This study completed a preliminary validation of the Mandarin Chinese version of the Pain Resilience Scale (PRS-C) with online survey data (n = 46). Further, we conducted interviews with individuals with chronic low back pain (n = 24).

RESULTS

The PRS-C psychometric properties were assessed using a confirmatory factor analysis. The interviews explored pain history, treatment experiences, and coping strategies and were analyzed thematically. The validated PRS-C (10 items) demonstrated satisfactory psychometric properties. The interview results showed that participants who scored lower were more likely to adopt disengagement rather than engagement coping strategies. Qualitative data revealed three themes explaining why and how participants in this collectivist social framework chose their coping methods.

CONCLUSIONS

The findings suggest that while participants tried to understand their pain and treatment experiences, the cognitive appraisal construct in PR influenced some of the coping experiences. However, deeply influenced by Confucianism and Buddhism, participants also expressed factors beyond the scope of individual fortitudes, such as the relationship with a higher power that significantly influenced their coping behaviors.

A critical review of the role of manual therapy in the treatment of individuals with low back pain

The number of low back pain (LBP) cases is projected to increase to more than 800 million by 2050. To address the substantial burden of disease associated with this rise in prevalence, effective treatments are needed. While clinical practice guidelines (CPG) consistently recommend non-pharmacological therapies as first-line treatments, recommendations regarding manual therapy (MT) in treating low back pain vary. The goal of this narrative review was to critically summarize the available evidence for MT behind these recommendations, to scrutinize its mechanisms of action, and propose some actionable steps for clinicians on how this knowledge can be integrated into a person-centered approach. Despite disparate recommendations from CPG, MT is as effective as other available treatments and may be offered to patients with LBP, especially as part of a treatment package with exercise and education. Most of the effects of MT are not specific to the technique. MT and other interventions share several mechanisms of action that mediate treatment success. These mechanisms can encompass patients' expectations, prior experiences, beliefs and convictions, epistemic trust, and nonspecific contextual effects. Although MT is safer than opioids for patients with LBP, this alone is insufficient. Our goal is to encourage clinicians to shift away from outdated and refuted ideas in MT and embrace a person-centered approach rooted in a comprehensive biopsychosocial framework while incorporating patients' beliefs, addressing illness behaviors, and seeking to understand each patient's journey.

Brain white matter pathways of resilience to chronic back pain: a multisite validation

Chronic back pain (CBP) is a global health concern with significant societal and economic burden. While various predictors of back pain chronicity have been proposed, including demographic and psychosocial factors, neuroimaging studies have pointed to brain characteristics as predictors of CBP. However, large-scale, multisite validation of these predictors is currently lacking. In two independent longitudinal studies, we examined white matter diffusion imaging data and pain characteristics in patients with subacute back pain (SBP) over six- and 12-month periods. Diffusion data from individuals with CBP and healthy controls (HC) were analyzed for comparison. Whole-brain tract-based spatial statistics analyses revealed that a cluster in the right superior longitudinal fasciculus (SLF) tract had larger fractional anisotropy (FA) values in patients who recovered (SBPr) compared to those with persistent pain (SBPp), and predicted changes in pain severity. The SLF FA values accurately classified patients at baseline and follow-up in a third publicly available dataset (Area under the Receiver Operating Curve ~ 0.70). Notably, patients who recovered had FA values larger than those of HC suggesting a potential role of SLF integrity in resilience to CBP. Structural connectivity-based models also classified SBPp and SBPr patients from the three data sets (validation accuracy 67%). Our results validate the right SLF as a robust predictor of CBP development, with potential for clinical translation. Cognitive and behavioral processes dependent on the right SLF, such as proprioception and visuospatial attention, should be analyzed in subacute stages as they could prove important for back pain chronicity.

Trends in Utilization and Cost of Nonpharmacological Pain Therapies in the United States Under Medicare Part B, 2000-2022

Background: Many clinical practice guidelines for management of pain disorders now favor first-line use of nonpharmacological therapies (NPT). However, Medicare coverage of NPT is limited. Methods: Using a serial cross-sectional design, we examined temporal trends in the utilization and cost of NPT procedures commonly used to treat pain under Medicare. Results: Utilization and costs for physical therapy increased while those for spinal and osteopathic manipulation declined. Discussion: Future research on NPT under Medicare should focus on equity of patient access and comparative outcomes.

Prolonged opioid use after single-level lumbar spinal fusion surgery in a Belgian population: a multicentric observational study

PURPOSE

Lumbar spinal fusion surgeries are increasingly being performed in spinal degenerative disease, often accompanied by perioperative opioid prescriptions. The aim of this study is to analyze prolonged postoperative opioid use following a standardized opioid prescription after single-level lumbar spinal fusion surgery in a Belgian population.

METHODS

This prospective, multicentric observational study included patients undergoing single-level lumbar fusion surgery for degenerative disease. A standardized postoperative opioid protocol (Targinact 2 × 10 mg/5 mg, Paracetamol 4 × 1 g and Ibuprofen 3 × 600 mg) was applied uniformly. Prolonged opioid use was defined as continued opioid use six months after surgery. Patient data were collected using the Back-App®.

RESULTS

Among 198 participants, 32.8% continued opioid use six months post-surgery, with 8% utilizing strong opioids. Prolonged opioid use correlated with lower pre-operative back pain. Patients with prolonged opioid use and strong opioid use at six months show less improvement in disability compared to patients without prolonged opioid use. Moreover, patients with prolonged strong opioid use tend to have lesser improvement of the low back pain. The odds for prolonged opioid use decrease with the increase of the improvement in ODI.

CONCLUSION

1 in 3 patients undergoing single-level lumbar spinal fusion surgery is at risk for prolonged opioid use. The study underscores the importance of tailored pain management strategies, particularly given the rising prevalence of spinal fusion surgeries. The association between pre-operative low back pain, post-operative improvement in functionality (ODI), and prolonged opioid use emphasizes the need for judicious opioid prescribing practices and highlights the role of functional outcomes in treatment goals.

Public versus Private Care in the Military Health System: Evidence From Low Back Pain Patients

INTRODUCTION

There is a longstanding debate about whether health care is more efficiently provided by the public or private sector. The debate is particularly relevant to the Military Health System (MHS), which delivers care through a combination of publicly funded federal facilities and privately contracted providers. This study compares outcomes, treatments, and costs for MHS patients obtaining care for low back pain (LBP) from public versus private providers.

MATERIALS AND METHODS

A retrospective cohort study was completed using TRICARE Prime claims data from April 2015 to December 2018. The cohort was identified using International Classification of Diseases Ninth Revision and Tenth Revision diagnostic codes and then followed for 12 months after the index diagnosis to assess treatments, outcomes, and costs. Claims were classified as originating from either public or private providers. The primary outcome measure was resolution of LBP, defined as an absence of LBP diagnoses during the 6-to-12-month window following the index event. Instrumental variable models were used to assess the impact of care setting (i.e., private versus public), conditioning on the covariates. A regional measure of the fraction of private care was used as an instrument.

RESULTS

Resolution of LBP was achieved for 79.7% of 144,866 patients in the cohort. No significant association was found between resolution of LBP and fraction of privately provided care. Higher fraction of private care was associated with a greater likelihood of opioid treatments (odds ratio, 1.22; 95% CI, 1.02-1.46) and a lower likelihood of benzodiazepine (odds ratio, 0.56; 95% CI, 0.45-0.70) and physical therapy (odds ratio 0.55; 95% CI, 0.42-0.74) treatments; manual therapy was not significantly associated with the fraction of private care. There was a significant negative association between the fraction of private care and cost (coefficient -0.27; 95% CI, -0.44, -0.10).

CONCLUSION

This study found that privately provided care was associated with significantly higher opioid prescribing, less use of benzodiazepines and physical therapy, and lower costs. No systematic differences in outcomes (as measured by resolved cases) were identified. The findings suggest that publicly funded health care within the MHS context can attain quality comparable to privately provided care, although differences in treatment choices and costs point to possibilities for improved care within both systems.

Nurse-led web-based self-management program to improve patient activation and health outcomes in patients with chronic low back pain: an acceptability and feasibility pilot study

BACKGROUND

Patients with chronic low back (cLBP) pain report reduced physical function and ability to participate in social roles and are more likely to use opioid pain medications. While self-management interventions have been shown to support these patients, their effectiveness has been limited due to poor patient engagement. "Patient activation" encompasses the skills, knowledge, and motivation that a person has to manage their health. Supporting patient activation may improve the effectiveness of self-management for cLBP.

METHODS

In this single-masked pilot study of adults with cLBP, patients were randomized to receive either no intervention (control) or 6 weekly sessions of an evidence-based web-based self-management program (SMP) with or without health behavior change counseling (HBCC) using motivational interviewing. Participants were assessed at baseline and at 12 and 26 weeks using the Patient Activation Measure, Oswestry Disability Index and PROMIS physical function, social role participation, and pain interference. We assessed acceptability and feasibility based on recruitment, session attendance, and follow-up.

RESULTS

Of 187 individuals screened, 105 were eligible and 34 were randomized to control (n = 12), SMP (n = 4), or SMP + HBCC (n = 18). The population had 19 women, 22 patients married or living with significant other, 13 Black or African American patients, and 4 Hispanic or Latino patients. Participants had a mean (SD) Oswestry Disability Index score of 42 (12), moderate impairments in physical function (40 (6.6)) and social roles (45 (10)), and moderately severe pain interference (61 (6.7)). Of 22 participants receiving SMP sessions, 20 participated in at least 1, 15 participated in at least 3, and 7 participated in all 6 sessions. Loss to follow-up was 6 over the 26-week study. Participants in the SMP and SMP + HBCC groups had at least medium effect size improvements in Patient Activation Measures and small-to-medium effect size improvements in Oswestry Disability Index scores and physical function and large effect size improvement in social roles at 12 weeks. Improvements persisted in the SMP + HBCC group at 26 weeks.

CONCLUSIONS

A web-based SMP is acceptable and feasible in this population. Participants who received augmentation with HBCC had persistent improvements in health outcomes at 26 weeks.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT06236529 (2/1/2024 - retrospectively registered).

LEVEL OF EVIDENCE: 3

Attentional Bias for Opioids in Taiwanese Heavy Smokers with Chronic Noncancer Pain

Background and Objectives: Attentional bias (AB) for addictive substances is a feature of attention found in individuals with substance misuse or diagnosed with substance use disorders. When AB exists, the attention of the addicted individual may be quickly oriented to cues related to the addictive substance or be maintained on these cues for a longer time. AB toward opioids was found in Western samples of smokers with chronic noncancer pain. The level of AB was dose-responsive. However, similar studies in the Taiwanese population are lacking. This study compared the patterns of AB for opioid analgesics in Taiwanese participants with chronic noncancer pain to that of individuals without pain. This study aimed to investigate if AB toward opioids is presented in Taiwanese heavy smokers who are on long-term opioid therapy for pain control. Materials and Methods: Participants were grouped into chronic noncancer pain smokers, chronic pain nonsmokers, and smokers without pain, according to smoking habits and whether or not on long-term opioid therapy for pain control. Each participant completed demographic questionnaires, mood scales, and the opioid-related visual probe task. Differences in AB among the groups were compared using a three-way analysis of covariance controlling for daily cigarette consumption. Results: Chronic noncancer pain smokers (n = 17) and chronic pain nonsmokers (n = 16) displayed more severe levels of depression, anxiety, and pain, compared to smokers without pain (n = 28). Only did chronic pain nonsmokers show significant AB for opioid cues that were displayed for a short time. Analysis on reaction time found that smokers without pain consistently responded faster to the tasks. No difference in reaction time was found between the pain groups. Conclusions: The current study did not fully replicate findings from studies that were based in Western countries. Formulary availability and regulatory limitations might have affected patient's perception of prescription opioids in Taiwan. However, chronic pain nonsmokers exhibited initial orientation toward opioid-related cues when daily cigarette consumption was accounted for. According to previous research, this AB for shortly displayed opioid cues can be associated with the expectation of pain relief. The current finding also indicated general psychomotor retardation in individuals who were on long-term use of opioids.

Concurrent and lagged associations among pain medication use, pain, and negative affect: a daily diary study of people with chronic low back pain

ABSTRACT

People with chronic pain often attempt to manage pain and concurrent emotional distress with analgesic substances. Habitual use of such substances-even when not opioid-based-can pose side effect risks. A negative reinforcement model has been proposed whereby relief of pain and emotional distress following medication consumption increases the likelihood that the experience of elevated pain and distress will spur further medication use. People with chronic low back pain (N = 105) completed electronic diary assessments 5 times/day for 14 consecutive days. Lagged and cross-lagged analyses focused on links between time 1 pain and negative affect (NA) and time 2 analgesic medication use and vice versa. Sex differences were also explored. Primary results were as follows: (1) participants on average reported taking analgesic medication during 41.3% of the 3-hour reporting epochs (29 times over 14 days); (2) time 1 within-person increases in pain and NA predicted time 2 increases in the likelihood of ingesting analgesic medications; (3) time 1 within-person increases in medication use predicted time 2 decreases in pain and NA; and (4) lagged associations between time 1 pain/NA and time 2 medication use were strongest among women. Findings suggest that the use of analgesic medications for many people with chronic pain occurs frequently throughout the day. Results support the validity of a negative reinforcement model where pain and distress lead to pain medication use, which in turn leads to relief from pain and distress.

Senescence of endplate osteoclasts induces sensory innervation and spinal pain

Spinal pain affects individuals of all ages and is the most common musculoskeletal problem globally. Its clinical management remains a challenge as the underlying mechanisms leading to it are still unclear. Here, we report that significantly increased numbers of senescent osteoclasts (SnOCs) are observed in mouse models of spinal hypersensitivity, like lumbar spine instability (LSI) or aging, compared to controls. The larger population of SnOCs is associated with induced sensory nerve innervation, as well as the growth of H-type vessels, in the porous endplate. We show that deletion of senescent cells by administration of the senolytic drug Navitoclax (ABT263) results in significantly less spinal hypersensitivity, spinal degeneration, porosity of the endplate, sensory nerve innervation and H-type vessel growth in the endplate. We also show that there is significantly increased SnOC-mediated secretion of Netrin-1 and NGF, two well-established sensory nerve growth factors, compared to non-senescent OCs. These findings suggest that pharmacological elimination of SnOCs may be a potent therapy to treat spinal pain.

Percutaneous lumbar interbody fusion results in less perioperative opioid usage compared to minimally invasive transforaminal lumbar interbody fusion: a single institution, multi-surgeon retrospective study

Background

Ultra-minimally invasive percutaneous lumbar interbody fusion (percLIF) has been demonstrated to further minimize tissue trauma and has been associated with improved clinical outcomes including decreased blood loss, post-operative pain and length of stay when compared to minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) surgery. A single-institution retrospective study was conducted to investigate whether 1-level percLIF is associated with decreased narcotic consumption compared to 1-level MIS-TLIF in the first 24-hour following surgery.

Methods

A retrospective study of patients undergoing either single-level percLIF or MIS-TLIF from January 2018 to December 2021. Opioid consumption in the 24-hour following surgery was converted into total morphine milligram equivalents (MME). The primary outcome used univariate and multivariate regression analysis to compare MME consumption between the MIS-TLIF and percLIF groups. Secondary outcome variables included, estimated blood loss, total intraoperative MME, MME at discharge, MME at 30 days post-op, exiting nerve root injury, post-anesthesia care unit (PACU) visual analogue scale (VAS) score at handoff, time to first ambulation, distance ambulated post-operative day one and hospital length of stay.

Results

A total of 51 patients (21 percLIF vs. 30 MIS-TLIF) were included in the study. Univariate regression analysis revealed that on average patients who underwent percLIF had a 24-hour postoperative MME -50.8 mg (95% CI: -91.6, -10) lower than those who had MIS-TLIF (P=0.02). On multivariable analysis, after adjusting for sex and age, 24-hour postoperative MME closely failed to meet statistical significance (P=0.06) with an average of -40.8 mg (95% CI: -83.2, 1.6) MME in percLIF patients compared to MIS-TLIF. There was no statistically significant difference in MME between MIS-TLIF and percLIF at the time of discharge and at 30 days post-op.

Conclusions

In the setting of the current opioid epidemic in the United States and increased numbers of patients undergoing lumbar interbody fusion, spine surgeons must continue to do their part helping reduce the need for opioid prescriptions for postoperative pain management. New "ultra-MIS" techniques such as percLIF allow surgeons to further decrease tissue trauma, which should lead to reduced need for post-operative narcotic requirements.

Senescence of endplate osteoclasts induces sensory innervation and spinal pain

Spinal pain affects individuals of all ages and is the most common musculoskeletal problem globally. Its clinical management remains a challenge as the underlying mechanisms leading to it are still unclear. Here, we report that significantly increased numbers of senescent osteoclasts (SnOCs) are observed in mouse models of spinal hypersensitivity, like lumbar spine instability (LSI) or aging, compared to controls. The larger population of SnOCs is associated with induced sensory nerve innervation, as well as the growth of H-type vessels, in the porous endplate. We show that deletion of senescent cells by administration of the senolytic drug Navitoclax (ABT263) results in significantly less spinal hypersensitivity, spinal degeneration, porosity of the endplate, sensory nerve innervation, and H-type vessel growth in the endplate. We also show that there is significantly increased SnOC-mediated secretion of Netrin-1 and NGF, two well-established sensory nerve growth factors, compared to non-senescent OCs. These findings suggest that pharmacological elimination of SnOCs may be a potent therapy to treat spinal pain.

Opioid Use Prior to Adult Spine Deformity Correction Surgery is Associated With Worse Pre- and Postoperative Back Pain and Prolonged Opioid Demands

STUDY DESIGN

Prospective multicenter database post-hoc analysis.

OBJECTIVES

Opioids are frequently prescribed for painful spinal conditions to provide pain relief and to allow for functional improvement, both before and after spine surgery. Amidst a current opioid epidemic, it is important for providers to understand the impact of opioid use and its relationship with patient-reported outcomes. The purpose of this study was to evaluate pre-/postoperative opioid consumption surrounding ASD and assess patient-reported pain outcomes in older patients undergoing surgery for spinal deformity.

METHODS

Patients ≥60 years of age from 12 international centers undergoing spinal fusion of at least 5 levels and a minimum 2-year follow-up were included. Patient-reported outcome scores were collected using the Numeric Rating Scale for back and leg pain (NRS-B; NRS-L) at baseline and at 2 years following surgery. Opioid use, defined based on a specific question on case report forms and question 11 from the SRS-22r questionnaire, was assessed at baseline and at 2-year follow-up.

RESULT

Of the 219 patients who met inclusion criteria, 179 (81.7%) had 2-year data on opioid use. The percentages of patients reporting opioid use at baseline (n = 75, 34.2%) and 2 years after surgery (n = 55, 30.7%) were similar (P = .23). However, at last follow-up 39% of baseline opioid users (Opi) were no longer taking opioids, while 14% of initial non-users (No-Opi) reported opioid use. Regional pre- and postoperative opioid use was 5.8% and 7.7% in the Asian population, 58.3% and 53.1% in the European, and 50.5% and 40.2% in North American patients, respectively. Baseline opioid users reported more preoperative back pain than the No-Opi group (7.0 vs 5.7, P = .001), while NRS-Leg pain scores were comparable (4.8 vs 4, P = .159). Similarly, at last follow-up, patients in the Opi group had greater NRS-B scores than Non-Opi patients (3.2 vs 2.3, P = .012), but no differences in NRS-Leg pain scores (2.2 vs 2.4, P = .632) were observed.

CONCLUSIONS

In this study, almost one-third of surgical ASD patients were consuming opioids both pre- and postoperatively world-wide. There were marked international variations, with patients from Asia having a much lower usage rate, suggesting a cultural influence. Despite both opioid users and nonusers benefitting from surgery, preoperative opioid use was strongly associated with significantly more back pain at baseline that persisted at 2-year follow up, as well as persistent postoperative opioid needs.

Getting what you pay for: impact of copayments on physical therapy and opioid initiation, timing, and continuation for newly diagnosed low back pain

BACKGROUND CONTEXT

Physical therapy (PT) is an important component of low back pain (LBP) management. Despite established guidelines, heterogeneity in medical management remains common.

PURPOSE

We sought to understand how copayments impact timing and utilization of PT in newly diagnosed LBP.

STUDY DESIGN/SETTING

The IBM Watson Health MarketScan claims database was used in a longitudinal setting.

PATIENT SAMPLE

Adult patients with LBP.

OUTCOME MEASURES

The primary outcomes-of-interest were timing and overall utilization of PT services. Additional outcomes-of-interest included timing of opioid prescribing.

METHODS

Actual and inferred copayments based on nonnonprimary care provider visit claims were used to evaluate the relationship between PT copayment and incidence of PT initiation. Multivariable regression models were used to evaluate factors influencing PT usage.

RESULTS

Overall, 2,467,389 patients were included. PT initiation, among those with at ≥1 PT service during the year after LBP diagnosis (30.6%), occurred at a median of 8 days postdiagnosis (IQR 1-55). Among those with at least one PT encounter, incidence of subsequent PT visits was significantly lower for those with high initial PT copayments. High initial PT copayments, while inversely correlated with PT utilization, were directly correlated with subsequent opioid use (0.77 prescriptions/patient [$0 PT copayment] versus 1.07 prescriptions/patient [$50-74 PT copayment]; 1.15 prescriptions/patient [$75+ PT copayment]). Among patients with known opioid and PT copayments, higher PT copayments were correlated with faster opioid use while higher opioid copayments were correlated with faster PT use (Spearman p<.05). For multivariable whole-cohort analyses, incidence of PT initiation among patients with inferred copayments in the 50-75th and 75-100th percentiles was significantly lower than those below the 50th percentile (HR=0.893 [95%CI 0.887-0.899] and HR=0.905 [95%CI 0.899-0.912], respectively).

CONCLUSIONS

Higher PT copayments correlated with reduced PT utilization; higher PT copayments and lower opioid copayments were independent contributors to delayed PT initiation and higher opioid use. In patients covered by plans charging high PT copayments, opioid use was significantly higher. Copays may impact long-term adherence to PT.

Functional ultrasound imaging of the human spinal cord

Utilizing the first in-human functional ultrasound imaging (fUSI) of the spinal cord, we demonstrate the integration of spinal functional responses to electrical stimulation. We record and characterize the hemodynamic responses of the spinal cord to a neuromodulatory intervention commonly used for treating pain and increasingly used for the restoration of sensorimotor and autonomic function. We found that the hemodynamic response to stimulation reflects a spatiotemporal modulation of the spinal cord circuitry not previously recognized. Our analytical capability offers a mechanism to assess blood flow changes with a new level of spatial and temporal precision in vivo and demonstrates that fUSI can decode the functional state of spinal networks in a single trial, which is of fundamental importance for developing real-time closed-loop neuromodulation systems. This work is a critical step toward developing a vital technique to study spinal cord function and effects of clinical neuromodulation.

The psychophysiology of music-based interventions and the experience of pain

In modern times there is increasing acceptance that music-based interventions are useful aids in the clinical treatment of a range of neurological and psychiatric conditions, including helping to reduce the perception of pain. Indeed, the belief that music, whether listening or performing, can alter human pain experiences has a long history, dating back to the ancient Greeks, and its potential healing properties have long been appreciated by indigenous cultures around the world. The subjective experience of acute or chronic pain is complex, influenced by many intersecting physiological and psychological factors, and it is therefore to be expected that the impact of music therapy on the pain experience may vary from one situation to another, and from one person to another. Where pain persists and becomes chronic, aberrant central processing is a key feature associated with the ongoing pain experience. Nonetheless, beneficial effects of exposure to music on pain relief have been reported across a wide range of acute and chronic conditions, and it has been shown to be effective in neonates, children and adults. In this comprehensive review we examine the various neurochemical, physiological and psychological factors that underpin the impact of music on the pain experience, factors that potentially operate at many levels - the periphery, spinal cord, brainstem, limbic system and multiple areas of cerebral cortex. We discuss the extent to which these factors, individually or in combination, influence how music affects both the quality and intensity of pain, noting that there remains controversy about the respective roles that diverse central and peripheral processes play in this experience. Better understanding of the mechanisms that underlie music's impact on pain perception together with insights into central processing of pain should aid in developing more effective synergistic approaches when music therapy is combined with clinical treatments. The ubiquitous nature of music also facilitates application from the therapeutic environment into daily life, for ongoing individual and social benefit.

Predictors of sexual satisfaction among patients with chronic pain

Objectives

Sexual satisfaction is an important aspect of quality of life. Chronic pain, depression and anxiety, and relational problems correspond with higher risk for sexual difficulties. Less is known about how risk factors for sexual dysfunction and other problems-such as medical conditions, pain severity, and medication side effects-affect the sexual satisfaction of people with chronic pain. Using a biopsychosocial framework, this study explored factors related to sexual satisfaction among patients presenting for evaluation of chronic pain.

Methods

Researchers used a hierarchical multiple regression analysis to model potential predictors of sexual satisfaction. Variables analyzed were demographic features, medical history, average pain severity, depressed mood, anxiety, and perceived significant other support. Data collection involved administration of retrospective questionnaires and chart review. The sample included male and female participants (N = 134) presenting for evaluation at a multidisciplinary pain rehabilitation clinic.

Results

Medical history (i.e., medical conditions, surgical history, and medications) and clinical self-report variables (i.e., pain severity, depressed mood, anxiety, and perceived significant other support) were associated with sexual satisfaction. In this sample, antidepressant use and higher pain severity were unique predictors of lower sexual satisfaction. Married marital status and higher levels of perceived significant other support were predictive of greater sexual satisfaction.

Discussion

Findings highlight the importance of understanding the unique impact of biopsychosocial variables on the sexual satisfaction of patients presenting for evaluation at a multidisciplinary pain rehabilitation clinic. Further exploration of protective factors that account for sexual satisfaction among individuals with chronic pain may help inform screening, referrals, and treatment.

Healthcare resource utilization for chronic low back pain among high-utilizers

BACKGROUND

Chronic low back pain is a leading cause of morbidity and is among the largest cost drivers for the healthcare system. Research on healthcare resource utilization of patients with low back pain who are not surgical candidates is limited, and few studies follow individuals who generate high healthcare costs over time.

PURPOSE

This claims study aimed to identify patients with high-impact mechanical, chronic low back pain (CLBP), quantify their low back pain-related health resource utilization, and explore associated patient characteristics. We hypothesize that patients in the top quartile of healthcare resource utilization in the second year after initial diagnosis will continue to generate considerable back pain-related costs in subsequent years.

STUDY DESIGN/SETTING

IBM MarketScan Research Databases from 2009-2019 were retrospectively analyzed.

PATIENT SAMPLE

Adults in the United States with an initial diagnosis of low back pain between 2010 and 2014 who did not have cancer, spine surgery, recent pregnancy, or inflammatory spine conditions, were identified using the International Classification of Diseases (ICD) and Current Procedural Terminology (CPT) codes. To ensure patients had chronic low back pain, it was required that individuals had additional claims with a low back pain diagnosis 6 to 12 and 12 to 24 months after initial diagnosis.

OUTCOME MEASURES

Cost and utilization of inpatient visits, outpatient visits, emergency room visits, pharmacologic and nonpharmacologic treatment options and imaging for chronic low back pain.

METHODS

Annual back pain-related costs and the use of pharmacologic and nonpharmacologic treatments for 5 years were analyzed. Logistic regression was utilized to identify factors associated with persistent high spending.

RESULTS

Of 16,917 individuals who met the criteria for chronic low back pain, 4,229 met the criteria for having high healthcare utilization, defined as being in the top quartile of back pain-related costs in the 12 to 24 months after their initial diagnosis. The mean and median back pain-related cost in the first year after an initial diagnosis was $7,112 (SD $9,670) and $4,405 (Q1 $2,147, Q3 $8,461). Mean and median back pain related costs in the second year were $11,989 (SD $20,316) and $5,935 (Q1 $3,892, Q3 $10,678). Costs continued to be incurred in years 3 to 5 at a reduced rate. The cumulative mean cost for back pain over the 5 years following the initial diagnosis was $31,459 (SD $39,545). The majority of costs were from outpatient services. Almost a quarter of the high utilizers remained in the top quartile of back pain-related costs during years 3 to 5 after the initial diagnosis, and another 19% remained in the top quartile for 2 of the 3 subsequent years. For these two groups combined (42%), the 5-year cumulative mean cost for back pain was $43,818 (SD $48,270). Patient characteristics associated with a higher likelihood of remaining as high utilizers were diabetes, having a greater number of outpatient visits and pharmacologic prescriptions, and lower utilization of imaging services.

CONCLUSION

This is one of the first studies to use an administrative claims database to identify high healthcare resource utilizers among a population of United States individuals with nonsurgical, chronic low back pain and follow their utilization over time. There was a population of individuals who continued to experience high costs 5 years beyond their initial diagnosis, and the majority of individuals continued to seek outpatient services. Further longitudinal claims research that incorporates symptom severity is needed to understand the economic implications of this condition.

Accuracy and efficacy of ultrasound-guided puncture (vs. computed tomography-guided) in cervical medial branch blocks for cervicogenic pain: A randomized controlled study

Cervical medial branch block (CMBB) has been recognized as an effective treatment for cervicogenic pain. Previous studies mostly used ultrasound-guided out-of-plane puncture for CMBB, while this prospective study was designed to investigate the efficacy of ultrasound-guided in-plane puncture, specifically focusing on the new target of CMBB for cervical pain. This study includes two parts: the accuracy study (N = 15, CMBB was completed by ultrasound and confirmed by computed tomography [CT], in which a good distribution percentage of the analgesic solution was observed) and the efficacy study (N = 40, CMBB was completed by ultrasound or CT, while the proportion of pain relief (numerical rating scale) decrease by more than 50% postoperatively was analyzed). The results showed that the good distribution percentage of the analgesic solution was 97.8%. Furthermore, in the early period (30 min and 2 h postoperatively), the proportion of patients with pain relief was lower in the ultrasound group than that in the CT group, especially at 2 h postoperatively (52% vs. 94%). However, at 24 h postoperatively and later, the proportion of patients with pain relief gradually stabilized to about 60%-70%, and lasted for about 2 weeks to 1 month. Therefore, the new target for CMBB, guided by ultrasound in-plane, offers high visibility and accuracy. A single CMBB performed under ultrasound guidance resulted in pain relief comparable to that of a CT-guided procedure (1 day to 1 month postoperatively). This study indicated that CMBB guided by ultrasound in-plane could be regarded as a promising approach for treatment of cervicogenic pain.

Research on the multidimensional brain remodeling mechanisms at the level of brain regions, circuits, and networks in patients with chronic lower back pain caused by lumbar disk herniation

Introduction

Chronic lower back pain (cLBP), frequently attributed to lumbar disk herniation (LDH), imposes substantial limitations on daily activities. Despite its prevalence, the neural mechanisms underlying lower back pain remain incompletely elucidated. Functional magnetic resonance imaging (fMRI) emerges as a non-invasive modality extensively employed for investigating neuroplastic changes in neuroscience. In this study, task-based and resting-state fMRI methodologies are employed to probe the central mechanisms of lower back pain.

Methods

The study included 71 chronic lower back pain patients (cLBP group) due to LDH and 80 age, gender, and education-matched healthy volunteers (HC group). The subjects are mainly middle-aged and elderly individuals. Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and Japanese Orthopedic Association Scores (JOA) were recorded. Resting-state and task-based fMRI data were collected.

Results/discussion

No significant differences were observed in age, gender, and education level between the two groups. In the cLBP group during task execution, there was diffuse and reduced activation observed in the primary motor cortex and supplementary motor area. Additionally, during resting states, notable changes were detected in brain regions, particularly in the frontal lobe, primary sensory area, primary motor cortex, precuneus, and caudate nucleus, accompanied by alterations in Amplitude of Low Frequency Fluctuation, Regional Homogeneity, Degree Centrality, and functional connectivity. These findings suggest that chronic lower back pain may entail reduced excitability in sensory-motor areas during tasks and heightened activity in the sensory-motor network during resting states, along with modified functional connectivity in various brain regions.

Increased HIF-2α activity in the nucleus pulposus causes intervertebral disc degeneration in the aging mouse spine

Hypoxia-inducible factors (HIFs) are essential to the homeostasis of hypoxic tissues. Although HIF-2α, is expressed in nucleus pulposus (NP) cells, consequences of elevated HIF-2 activity on disc health remains unknown. We expressed HIF-2α with proline to alanine substitutions (P405A; P531A) in the Oxygen-dependent degradation domain (HIF-2αdPA) in the NP tissue using an inducible, nucleus pulposus-specific K19CreERT allele to study HIF-2α function in the adult intervertebral disc. Expression of HIF-2α in NP impacted disc morphology, as evident from small but significantly higher scores of degeneration in NP of 24-month-old K19CreERT; HIF-2αdPA (K19-dPA) mice. Noteworthy, comparisons of grades within each genotype between 14 months and 24 months indicated that HIF-2α overexpression contributed to more pronounced changes than aging alone. The annulus fibrosus (AF) compartment in the 14-month-old K19-dPA mice exhibited lower collagen turnover and Fourier transform-infrared (FTIR) spectroscopic imaging analyses showed changes in the biochemical composition of the 14- and 24-month-old K19-dPA mice. Moreover, there were changes in aggrecan, chondroitin sulfate, and COMP abundance without alterations in NP phenotypic marker CA3, suggesting the overexpression of HIF-2α had some impact on matrix composition but not the cell phenotype. Mechanistically, the global transcriptomic analysis showed enrichment of differentially expressed genes in themes closely related to NP cell function such as cilia, SLIT/ROBO pathway, and HIF/Hypoxia signaling at both 14- and 24-month. Together, these findings underscore the role of HIF-2α in the pathogenesis of disc degeneration in the aged spine.

Risk of fall or fracture with concomitant use of prescription opioids and other medications in osteoarthritis patients

BACKGROUND

Osteoarthritis (OA) patients taking prescription opioids for pain are at increased risk of fall or fracture, and the concomitant use of interacting drugs may further increase the risk of these events.

AIMS

To identify prescription opioid-related medication combinations associated with fall or fracture.

MATERIALS & METHODS

We conducted a case-crossover-based screening of two administrative claims databases spanning 2003 through 2021. OA patients were aged 40 years or older with at least 365 days of continuous enrollment and 90 days of continuous prescription opioid use before their first eligible fall or fracture event. The primary analysis quantified the odds ratio (OR) between fall and non-opioid medications dispensed in the 90 days before the fall date after adjustment for prescription opioid dosage and confounding using a case-time-control design. A secondary analogous analysis evaluated medications associated with fracture. The false discovery rate (FDR) was used to account for multiple testing.

RESULTS

We identified 41 693 OA patients who experienced a fall and 24 891 OA patients who experienced a fracture after at least 90 days of continuous opioid therapy. Top non-opioid medications by ascending p-value with OR > 1 for fall were meloxicam (OR 1.22, FDR = 0.08), metoprolol (OR 1.06, FDR >0.99), and celecoxib (OR 1.13, FDR > 0.99). Top non-opioid medications for fracture were losartan (OR 1.20, FDR = 0.80), alprazolam (OR 1.14, FDR > 0.99), and duloxetine (OR 1.12, FDR = 0.97).

CONCLUSION

Clinicians may seek to monitor patients who are co-prescribed drugs that act on the central nervous system, especially in individuals with OA.

The Effect of Preoperative Marijuana Use on Surgical Outcomes, Patient-Reported Outcomes, and Opioid Consumption Following Lumbar Fusion

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVES

To (1) investigate the effect of marijuana use on surgical outcomes following lumbar fusion, (2) determine how marijuana use affects patient-reported outcomes measures (PROMs), and (3) determine if marijuana use impacts the quantity of opioids prescribed.

METHODS

Patients > 18 years of age who underwent primary one- or two-level lumbar fusion with preoperative marijuana use at our institution were identified. A 3:1 propensity match incorporating patient demographics and procedure type was conducted to compare preoperative marijuana users to non-marijuana users. Patient demographics, surgical characteristics, surgical outcomes (90-day all-cause and 90-day surgical readmissions, reoperations, and revision surgeries), pre- and postoperative narcotic usage, and PROMs were compared between groups. Multivariate regression models were created to determine the effect of marijuana on surgical reoperations patient-reported outcomes (PROMs) 1-year postoperatively.

RESULTS

Of the 259 included patients, 65 used marijuana preoperatively. Multivariate logistic regression analysis demonstrated that marijuana use (OR = 2.28, P = .041) significantly increased the likelihood of having a spine reoperation. No other surgical outcome was found to be significantly different between groups. Multivariate linear regression analysis showed that marijuana use was not significantly associated with changes in 1-year postoperative PROMs (all, P > .05). The quantity of pre- and postoperative opioids prescriptions was not significantly different between groups (all, P > .05).

CONCLUSIONS

Preoperative marijuana use increased the likelihood of a spine reoperation for any indication following lumbar fusion, but it was not associated with 90-day all cause readmission, surgical readmission, the magnitude of improvement in PROMs, or differences in opioid consumption.

LEVEL OF EVIDENCE

III.

Trends, outcomes, and factors associated with in-hospital opioid overdose following major surgery

Background

With the growing opioid epidemic across the US, in-hospital utilization of opioids has garnered increasing attention. Using a national cohort, this study sought to characterize trends, outcomes, and factors associated with in-hospital opioid overdose (OD) following major elective operations.

Methods

We identified all adult (≥18 years) hospitalizations entailing select elective procedures in the 2016-2020 National Inpatient Sample. Patients who experienced in-hospital opioid overdose were characterized as OD (others: Non-OD). The primary outcome of interest was in-hospital OD. Multivariable logistic and linear regression models were developed to evaluate the association between in-hospital OD and mortality, length of stay (LOS), hospitalization costs, and non-home discharge.

Results

Of an estimated 11,096,064 hospitalizations meeting study criteria, 5375 (0.05 %) experienced a perioperative OD. Compared to others, OD were older (66 [57-73] vs 64 [54-72] years, p < 0.001), more commonly female (66.3 vs 56.7 %, p < 0.001), and in the lowest income quartile (26.4 vs 23.2 %, p < 0.001). After adjustment, female sex (Adjusted Odds Ratio [AOR] 1.68, 95 % Confidence Interval [CI] 1.47-1.91, p < 0.001), White race (AOR 1.19, CI 1.01-1.42, p = 0.04), and history of substance use disorder (AOR 2.51, CI 1.87-3.37, p < 0.001) were associated with greater likelihood of OD. Finally, OD was associated with increased LOS (β +1.91 days, CI [1.60-2.21], p < 0.001), hospitalization costs (β +$7500, CI [5900-9100], p < 0.001), and greater odds of non-home discharge (AOR 2.00, CI 1.61-2.48, p < 0.001).

Conclusion

Perioperative OD remains a rare but costly complication after elective surgery. While pain control remains a priority postoperatively, protocols and recovery pathways must be re-examined to ensure patient safety.

Nociceptive pain assessed by the PainDETECT questionnaire may predict response to opioid treatment for chronic low back pain

Introduction

The pharmacological management of chronic low back pain (LBP) is complex. The World Health Organisation recommends a laddered approach to pain medication usage. The PainDETECT questionnaire distinguishes between neuropathic pain (NeP), nociceptive pain (NoP), and ambiguous pain. By elucidating the difference in medication efficacy between these groups, clinicians can provide a tailored treatment plan to manage patient's pain. This study aimed to investigate the relationship between pharmacological treatments, pain categorizations, and medication efficacy as reported by patients.

Methods

A secondary retrospective analysis of a prospectively collected database was conducted involving 318 consecutively recruited patients, aged 18 years and above, who completed PainDETECT, medication history and patient reported medication efficacy questionnaires. Medication history was categorized into four lines of treatment: first line (paracetamol ± non-prescribed anti-inflammatories), second line (prescribed anti-inflammatories), third line (anticonvulsants/neuromodulators) and fourth line (opioids). Medication efficacy was measured using a three-point Likert scale: effective (+2), somewhat effective (+1), no effect (0).

Findings

The study included 120, 50, 54 and 94 patients on first line, second line, third line and fourth line treatment, respectively. The NeP group had higher mean numerical rating scale (NRS) compared to NoP group in all four lines of treatment (8.10 ± 1.59 vs. 5.47± 2.27, p < 0.001, 8.64± 1.43 vs. 5.52± 1.86, p < 0.001, 8.00± 1.07 vs. 6.37± 2.39, p < 0.01, and 8.05± 1.73 vs. 7.2± 1.29, p < 0.05). When confounding for severity of LBP as measured by NRS, the distribution of medication efficacy significantly differed amongst the NeP, ambiguous and NoP groups in patients undergoing fourth line pharmacological treatment (r2 = 8.623, p < 0.05). The NoP group exhibited significantly higher medication efficacy compared to the NeP group (U = 14.038, p < 0.05). There was no significant difference in medication efficacy across the pain classifications for first, second- and third-line treatment.

Interpretation

Opioids was the only line of treatment more effective in targeting NoP, as determined by the PainDETECT questionnaire, compared to NeP. This pioneering study illustrates the complex nature of pharmacological management for chronic LBP. It underscores the importance of tailoring pharmacological treatment plans to fit individual pain profiles and expectations instead of adopting a blanket approach to pain management.

What a pain in the … back: a review of current treatment options with a focus on naproxen sodium

Non-specific low back pain (LBP) represents a challenging and prevalent condition that is one of the most common symptoms leading to primary care physician visits. While established guidelines recommend prioritizing non-pharmacological approaches as the primary course of action, pharmacological treatments are advised when non-pharmacological approaches are ineffective or based on patient preference. These guidelines recommend non-steroidal anti-inflammatory drugs (NSAIDs) or skeletal muscle relaxers (SMRs) as the first-line pharmacological options for acute or subacute LBP, while NSAIDs are the exclusive first-line pharmacological option for chronic LBP. Although SMRs are generally effective for acute LBP, the available evidence does not support the view that they improve functional recovery, and their comparative efficacy to NSAIDs and other analgesics remains unknown, while studies have shown them to introduce adverse events without significantly reducing LBP. Moreover, opioids continue to be widely prescribed for LBP, despite limited evidence for effectiveness and known risks of addiction and overdose. Broader use of non-opioid pharmacotherapy, including the appropriate use of OTC options, is critical to addressing the opioid crisis. The balance of evidence indicates that NSAIDs have a favorable benefit-risk profile when compared to other available pharmacological treatment options for non-specific LBP, a condition that is primarily acute in nature and well-suited for self-treatment with OTC analgesics. While clinical guidelines do not differentiate between NSAIDs, evidence indicates that OTC naproxen sodium effectively relieves pain across multiple types of pain models, and furthermore, the 14-h half-life of naproxen sodium allows sustained, all day pain relief with reduced patient pill burden as compared to shorter acting options. Choosing the most appropriate approach for managing LBP, including non-pharmacological options, should be based on the patient's condition, severity of pain, potential risks, and individual patient preference and needs.

Understanding general practitioners' prescribing choices to patients with chronic low back pain: a discrete choice experiment

BACKGROUND

Although NSAIDs are recommended as a first line analgesic treatment, opioids are very commonly prescribed to patients with low back pain (LBP) despite risks of harms.

AIM

This study aimed to determine factors contributing to general practitioners' (GPs') prescribing choices to patients with chronic LBP in a primary care setting.

METHOD

This discrete choice experiment (DCE) presented 210 GPs with hypothetical scenarios of a patient with chronic LBP. Participants chose their preferred treatment for each choice set, either the opioid, NSAID or neither. The scenarios varied by two patient attributes; non-specific LBP or LBP with referred leg pain (sciatica) and number of comorbidities. The three treatment attributes also varied, being: the type of opioid or NSAID, degree of pain reduction and number of adverse events. The significance of each attribute in influencing clinical decisions was the primary outcome and the degree to which GPs preferred the alternative based on the number of adverse events or the amount of pain reduction was the secondary outcome.

RESULTS

Overall, GPs preferred NSAIDs (45.2%, 95% CI 38.7-51.7%) over opioids (28.8%, 95% CI 23.0-34.7%), however there was no difference between the type of NSAID or opioid preferred. Additionally, the attributes of pain reduction and adverse events did not influence a GP's choice between NSAIDs or opioids for patients with chronic LBP.

CONCLUSION

GPs prefer prescribing NSAIDs over opioids for a patient with chronic low back pain regardless of patient factors of comorbidities or the presence of leg pain (i.e. sciatica).

Translation, cross-cultural adaptation and psychometric properties of the Urdu version of the back pain functional scale in low back pain patients

BACKGROUND

Translation and validation of important scales in other languages reduce bias in reporting the functional status of the patient.

OBJECTIVE

To translate the Back Pain Functional Scale into Urdu (BPFSu), adapt it for use in other cultures, and evaluate its psychometric properties.

METHOD

According to Beaton guidelines, translation and cultural adaption was carried out. On 100 Urdu-literate men and women aged 18-60 years with lower back pain, the final BPFSu was assessed for psychometric qualities. First at baseline and again after 7 days, participants completed the BPFSu, the Functional Rating Index (FRI), and the Numeric Pain Rating Scale (NPRS).

RESULTS

Internal consistency of the BPFSu was excellent (Cronbach's alpha: 0.937). No floor and ceiling effects were found Excellent test-retest reliability (ICC = 0.882, CI 95%; 0.830-0.919) was achieved. Spearman correlation coefficient showed criterion validity with the NPRS (rho =â⁢⁢0.701, p⩽ 0.001) and Pearson correlation coefficient showed construct validity with the FRI (r=â⁢⁢0.740, p⩽ 0.001). The minimum detectable changes were 9.96, while the standard error of measurement was 3.6.

CONCLUSION

The BPFSu is a valid and reliable instrument for assessing physical function in individuals experiencing low back discomfort.

Post-Operative Complications Associated with Long-Term NSAID or Long-Term Opioid Use Prior to Lumbar Spinal Fusion Surgery

OBJECTIVE

Lower back pain (LBP) has been implicated as a significant cause of chronic pain in the United States, often requiring analgesic use. In this study, we investigate the trends in long-term preoperative NSAID (LTN) and Opioid (LTO) use in patients with low back pain in the United States, and the resultant postoperative complications following lumbar fusion.

METHODS

In this retrospective cohort study of patients with lumbar pathologies, multivariate population-based regression models were developed using the 2010-2017 National Readmission Database. Short-term complications (30-, 90-day) and long-term complications (180-, 300-day) were analyzed at readmission.

RESULTS

Of patients diagnosed with LBP (N = 1427,190) we found a rise in LTO users and a fall in LTN users following 2015. We identified 654,264 individuals who received a lumbar spine fusion, of which 22,975 were LTN users and 11,213 were LTO users. LTO users had significantly higher total inpatient charges (p-value<0.0001) and LOS (p-value<0.0001), while LTN users had lower rates of acute infection (OR: 0.993, 95% CI: 0.987-0.999, p = 0.017) and acute posthemorrhagic anemia (OR: 0.957, 95% CI: 0.935-0.979, p < 0.001) at primary admission. Readmission analysis showed that LTN use had significantly lower odds of readmission compared to LTO use at all time points (p < 0.01 for all). LTN use had significantly higher odds of hardware failure (OR: 1.134, 95% CI: 1.039-1.237, p = 0.005) within 300-days of receiving a lumbar fusion.

CONCLUSIONS

LTO users had significantly higher readmission rates compared to LTN. In addition, we found that LTN use was associated with significantly higher odds of hardware failure at long-term follow-up in patients receiving lumbar fusion surgery.

Central Sensitization and Pain: Pathophysiologic and Clinical Insights

Central sensitization is an increased responsiveness of nociceptive neurons in the central nervous system to their normal or subthreshold afferent input.

AIM

To explain how the notion of central sensitization has changed our understanding of pain conditions, discuss how this knowledge can be used to improve the management of pain, and highlight knowledge gaps that future research needs to address.

METHODS

Overview of definitions, assessment methods, and clinical implications.

RESULTS

Human pain models, and functional and molecular imaging have provided converging evidence that central sensitization occurs and is clinically relevant. Measures to assess central sensitization in patients are available; however, their ability to discriminate sensitization of central from peripheral neurons is unclear. Treatments that attenuate central sensitization are available, but the limited understanding of molecular and functional mechanisms hampers the development of target-specific treatments. The origin of central sensitization in human pain conditions that are not associated with tissue damage remains unclear.

CONCLUSION

The knowledge of central sensitization has revolutionized our neurobiological understanding of pain. Despite the limitations of clinical assessment in identifying central sensitization, it is appropriate to use the available tools to guide clinical decisions towards treatments that attenuate central sensitization. Future research that elucidates the causes, molecular and functional mechanisms of central sensitization would provide crucial progress towards the development of treatments that target specific mechanisms of central sensitization.

Increased HIF-2α Activity in the Nucleus Pulposus Causes Intervertebral Disc Degeneration in the Aging Mouse Spine

Hypoxia-inducible factors (HIFs) are essential to the homeostasis of hypoxic tissues. Although HIF-2α, is expressed in nucleus pulposus (NP) cells, consequences of elevated HIF-2 activity on disc health remains unknown. We expressed HIF-2α with proline to alanine substitutions (P405A;P531A) in the Oxygen-dependent degradation domain (HIF-2αdPA) in the NP tissue using an inducible, nucleus pulposus-specific K19 CreERT allele to study HIF-2α function in the adult intervertebral disc. Expression of HIF-2α in NP impacted disc morphology, as evident from small but significantly higher scores of degeneration in NP of 24-month-old K19 CreERT ; HIF-2α dPA (K19-dPA) mice. Noteworthy, comparisons of grades within each genotype between 14 months and 24 months indicated that HIF-2α overexpression contributed to more pronounced changes than aging alone. The annulus fibrosus (AF) compartment in the 14-month-old K19-dPA mice exhibited lower collagen turnover and Fourier transform-infrared (FTIR) spectroscopic imaging analyses showed changes in the biochemical composition of the 14-and 24-month-old K19-dPA mice. Moreover, there were changes in aggrecan, chondroitin sulfate, and COMP abundance without alterations in NP phenotypic marker CA3, suggesting the overexpression of HIF-2α had some impact on matrix composition but not the cell phenotype. Mechanistically, the global transcriptomic analysis showed enrichment of differentially expressed genes in themes closely related to NP cell function such as cilia, SLIT/ROBO pathway, and HIF/Hypoxia signaling at both 14- and 24-months. Together, these findings underscore the role of HIF-2α in the pathogenesis of disc degeneration in the aged spine.

Combined Rehabilitation with Alpha Lipoic Acid, Acetyl-L-Carnitine, Resveratrol, and Cholecalciferolin Discogenic Sciatica in Young People: A Randomized Clinical Trial

Background and Objectives: In the Western world, back pain and sciatica are among the main causes of disability and absence from work with significant personal, social, and economic costs. This prospective observational study aims to evaluate the effectiveness of a rehabilitation program combined with the administration of Alpha Lipoic Acid, Acetyl-L-Carnitine, Resveratrol, and Cholecalciferol in the treatment of sciatica due to herniated discs in young patients in terms of pain resolution, postural alterations, taking painkillers, and quality of life. Materials and Methods: A prospective observational study was conducted on 128 patients with sciatica. We divided the sample into 3 groups: the Combo group, which received a combination of rehabilitation protocol and daily therapy with 600 mg Alpha Lipoic Acid, 1000 mg Acetyl-L-Carnitine, 50 mg Resveratrol, and 800 UI Cholecalciferol for 30 days; the Reha group, which received only a rehabilitation protocol; and the Supplement group, which received only oral supplementation with 600 mg Alpha Lipoic Acid, 1000 mg Acetyl-L-Carnitine, 50 mg Resveratrol, and 800 UI Cholecalciferol. Clinical assessments were made at the time of recruitment (T0), 30 days after the start of treatment (T1), and 60 days after the end of treatment (T2). The rating scales were as follows: the Numeric Rating Scale (NRS); the Oswestry Disability Questionnaire (ODQ); and the 36-item Short Form Health Survey (SF-36). All patients also underwent an instrumental stabilometric evaluation. Results: At T1, the Combo group showed statistically superior results compared to the other groups for pain (p < 0.05), disability (p < 0.05), and quality of life (p < 0.05). At T2, the Combo group showed statistically superior results compared to the other groups only for pain (p < 0.05) and quality of life (p < 0.05). From the analysis of the stabilometric evaluation data, we only observed a statistically significant improvement at T2 in the Combo group for the average X (p < 0.05) compared to the other groups. Conclusions: The combined treatment of rehabilitation and supplements with anti-inflammatory, pain-relieving, and antioxidant action is effective in the treatment of sciatica and can be useful in improving postural stability.

Efficacy and safety of thermobalancing therapy with Dr Allen's Device for chronic low back pain: A randomised controlled trial

BACKGROUND

Lumbar disc herniation and non-specific low back pain are common conditions that seriously affect patients' health-related quality of life (HRQoL). Although empirical evidence has demonstrated that novel Thermobalancing therapy and Dr Allen's Device can relieve chronic low back pain, there have been no randomised controlled trials for these indications.

AIM

To evaluate the efficacy of Dr Allen's Device in lumbar disc herniation (LDH) and non-specific low back pain (NSLBP).

METHODS

A randomised clinical trial was conducted investigating 55 patients with chronic low back pain due to LDH (n = 28) or NSLBP (n = 27), out of which 15 were randomly assigned to the control group and 40 were assigned to the treatment group. The intervention was treatment with Dr Allen's Device for 3 mo. Changes in HRQoL were assessed using the Numerical Pain Rating Scale and the Japanese Orthopedic Association Back Pain Questionnaire.

RESULTS

Thermobalancing therapy with Dr Allen's Device showed a significant reduction in pain in the treatment group (P < 0.001), with no recorded adverse effects. Both pain assessment scales showed a significant improvement in patients' perception of pain indicating improvement in HRQoL.

CONCLUSION

The out-of-hospital use of Thermobalancing therapy with Dr Allen's Device for Low Back Treatment relieves chronic low back pain significantly and without adverse effects, improves the level of activity and HRQoL among patients with LDH and NSLBP. This study demonstrates the importance of this safe first-line therapy that can be used for effective at-home management of chronic low back pain.

Medical Cannabis and Its Efficacy/Effectiveness for the Treatment of Low-Back Pain: a Systematic Review

PURPOSE OF REVIEW

This systematic review aims to inform the current state of evidence about the efficacy and effectiveness of medical cannabis use for the treatment of LBP, specifically on pain levels and overall opioid use for LBP. Searches were conducted in MEDLINE (PubMed), Embase, and CINAHL. The search was limited to the past 10 years (2011-2021). Study inclusion was determined by the critical appraisal process using the Joanna Briggs Institute framework. Only English language articles were included. Participant demographics included all adult individuals with LBP who were prescribed medical cannabis for LBP and may be concurrently using opioids for their LBP. Study quality and the risk of bias were both evaluated. A narrative synthesis approach was used.

RECENT FINDINGS

A total of twelve studies were included in the synthesis: one randomized controlled trial (RCT), six observational studies (one prospective, four retrospective, and one cross-over), and five case studies. All study results, except for the RCT, indicated a decrease in LBP levels or opioid use over time after medical cannabis use. The RCT reported no statistically significant difference in LBP between cannabis and placebo groups. Low back pain (LBP) affects 568 million people worldwide. In the United States, LBP treatment represents more than half of regular opioid users. With the opioid epidemic, alternative methods, particularly medical cannabis, is now increasingly sought by practicing physicians and patients. Due to its infancy, there is minimal high-quality evidence to support medical cannabis use as a first line treatment for LBP.

Real World Characterization of Chronic Pain, Success Rates and Implant Rates: Evidence from a Digital Health Platform of Patients Undergoing Spinal Cord Stimulation Evaluations

Spinal cord stimulation is an effective treatment for those experiencing chronic back and leg pain but requires a temporary evaluation period (SCSeval) before permanent implantation. We present real-world data from 7,000 patients who underwent SCSeval while utilizing a mobile digital health platform for education, feedback, and outcomes collection during their surgical journey. We analyzed preoperative patient demographics, characterized patient pain profiles using the patient-reported outcomes measurement information system-29 surveys, and calculated the rates of conversion from temporary to permanent spinal cord stimulation (SCS) implantation. Between August 1, 2021, and March 2, 2023, 7,000 patients (mean age 59.1, 59.6% female) underwent SCSeval procedures while utilizing a mobile application. Patients commonly experienced aching, sharp, stabbing, tingling, numb, and burning pain. Patients had tried multiple prior therapies and wanted to reduce their use of opioids and pain medications. Overall, 90.1% of the patients had a successful SCSeval, and 80.4% of those converted to permanent implant, with the highest rates among those who underwent SCSeval in a hospital setting. There was a significant improvement in all domains of pain as evaluated by pre and postoperative patient-reported outcomes measurement information system-29 surveys. This study supports the use of digital health technology as part of the SCS journey to improve the patient experience and allow for robust patient-reported outcomes collection. The overall rate of SCSeval to permanent SCS in our study of 72.4% was higher than national rates of 64%, suggesting that an app may allow clinicians to better quantify changes in chronic pain and provide more insight into choosing to implant SCS permanently. PERSPECTIVE: This article presents real-world evidence from a digital health platform for therapy education and outcomes collection from patients undergoing spinal cord stimulation evaluation procedures. Such tools could allow for better pain characterization and allow for more nuanced tracking of patient outcomes among those with chronic pain.

Altered effective connectivity from cerebellum to motor cortex in chronic low back pain: A multivariate pattern analysis and spectral dynamic causal modeling study

To explore the central processing mechanism of pain perception in chronic low back pain (cLBP) using multi-voxel pattern analysis (MVPA) based on the static and dynamic fractional amplitude of low-frequency fluctuations (fALFF) analysis, and spectral dynamic causal modeling (spDCM). Thirty-two patients with cLBP and 29 matched healthy controls (HCs) for the first cohort and 24 patients with cLBP and 22 HCs for the validation cohort underwent resting-state fMRI scan. The alterations in static and dynamic fALFF were as classification features to distinguish patients with cLBP from HCs. The brain regions gotten from the MVPA results were used for further spDCM analysis. We found that the most discriminative brain regions that contributed to the classification were the right supplementary motor area (SMA.R), left paracentral lobule (PCL.L), and bilateral cerebellar Crus II. The spDCM results displayed decreased excitatory influence from the bilateral cerebellar Crus II to PCL.L in patients with cLBP compared with HCs. Moreover, the conversion of effective connectivity from the bilateral cerebellar Crus II to SMA.R from excitatory influence to inhibitive influence, and the effective connectivity strength exhibited partially mediated effects on Chinese Short Form Oswestry Disability Index Questionnaire (C-SFODI) scores. Our findings suggest that the cerebellum and its weakened or inhibited connections to the motor cortex may be one of the underlying feedback pathways for pain perception in cLBP, and partially mediate the degree of dysfunction.

Can Electroacupuncture Be Useful in Opioid-Induced Hyperalgesia? A Case Report

Opioid-induced hyperalgesia (OIH) is characterized by a paradoxical increase in pain sensitivity following opioid exposure. Although animal models indicate that electroacupuncture (EA) is effective against pain sensitization, there are no reports of its clinical application in OIH treatment. This case report involves an adult patient with osteomalacia complicated by multiple vertebral fragility fractures. The patient developed OIH following the use of oxycodone to treat severe disabling lower back pain that was refractory to nonsteroidal anti-inflammatory drugs. After hospitalization and treatment with low EA-frequency (2-10 Hz) sessions, the patient exhibited significant pain reduction and functional recovery after the first session, which was accompanied by steady progressive improvement as the treatment continued. This case report illustrates the clinical efficacy of EA in OIH treatment and indicates that EA, which has multiple modes of action on the neurobiology of chronic pain, has potential applications in the management of complex and difficult-to-manage conditions, such as OIH.

Analgesic effects of perioperative acupuncture methods: A narrative review

Postoperative pain occurs immediately after surgery. The most common perioperative analgesic methods are nerve block, patient-controlled intravenous analgesia, and patient-controlled epidural analgesia. However, overuse of opioid analgesics can cause many adverse reactions including excessive sedation, respiratory inhibition, postoperative nausea, and vomiting. In recent years, many clinical trials have shown that perioperative acupuncture has unique advantages in patients. Perioperative acupuncture can relieve intraoperative pain, improve postoperative pain management, reduce postoperative nausea and vomiting, and shorten the length of hospital stay. This study aimed to confirm the analgesic effect of perioperative acupuncture by reviewing studies on the different methods of perioperative acupuncture and their analgesic effects. The cited literature was searched in English and Chinese from PubMed, China National Knowledge Infrastructure, and Wanfang data, using the following keywords: "perioperative pain," "acupuncture," "electroacupuncture," and "perioperative analgesia." Studies published from 2005 to 2023 were included. All retrieved papers were read in detail. Perioperative acupuncture has benefits in reducing postoperative pain and opioid need. Although analgesic drugs are still the primary means of postoperative pain control, acupuncture provides a safe analgesic supplement or alternative. This review aimed to assist practitioners in choosing appropriate perioperative acupuncture methods by summarizing the recent literature on the role of different acupuncture approaches for perioperative pain management.

Functional disruptions of the brain network in low back pain: a graph-theoretical study

PURPOSE

The aim of this study was to investigate alterations in the topological organization of whole-brain functional networks in patients with chronic low back pain (CLBP) and characterize the relationship of these alterations with pain characteristics.

METHODS

Thirty-three CLBP patients and 34 matched healthy controls (HCs) underwent fMRI scans. A graph-theoretical approach was applied to identify brain network changes in patients suffering from chronic low back pain given its nonspecific etiology and complexity. Graph theory-based analysis was used to construct functional connectivity matrices and extract the features of small-world networks of the brain in both groups. Then, the whole-brain functional connectivity differences were characterized by network-based statistics (NBS) analysis, and the relationship between the altered brain features and clinical measures was explored.

RESULTS

At the global level, patients with CLBP showed significantly decreased gamma, sigma, global efficiency, and local efficiency and increased lambda and shortest path length compared with HCs. At the regional level, there were deficits in nodal efficiency within the default mode network and salience network. NBS analysis demonstrated that decreased functional connectivity was present in the CLBP patients, mainly in the frontolimbic circuit and temporal regions. Furthermore, aspects of topological dysfunctions in CLBP were correlated with pain severity.

CONCLUSION

This study highlighted the aberrant topological organization of functional brain networks in CLBP, which may shed light on the pathophysiology of CLBP and support the development of pain management approaches.

Various Doses of Tanezumab in the Management of Chronic Low Back Pain (CLBP): A Pooled Analysis of 4,514 Patients

Chronic low back pain (CLBP) is a persistent and debilitating condition characterized by pain and discomfort in the lower back region that lasts more than 12 weeks. This review aims to determine the efficacy and safety of various doses of tanezumab for managing CLBP. The present meta-analysis was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and the Cochrane Handbook for Systematic Reviews of Intervention standards. We searched multiple databases, including PubMed, Cochrane Library, Excerpta Medica Database (EMBASE), Scopus, and Web of Science, to identify randomized controlled trials comparing tanezumab to placebo or different dosage regimens for CLBP in adult patients. The primary outcome was the mean change in low back pain intensity (LBPI) score baseline to the end of treatment. Secondary outcomes included adverse events and the degree of disability or impairment. A total of six studies were included in the meta-analysis. Analysis of the data showed that tanezumab 5 mg significantly reduced LBPI compared to placebo at all time points (mean deviation (MD) ranging from -0.31 to -0.5). Similarly, tanezumab 10 mg showed a significant reduction in LBPI compared to placebo at all time points (MD ranging from -0.48 to -0.84). However, tanezumab 5 mg showed significantly less reduction of LBPI compared to 10 mg at two, four, eight, and 12 weeks (MD ranging from 0.19 to 0.32). These findings suggest that tanezumab is an effective treatment for CLBP, with 5 mg and 10 mg doses providing clinically meaningful reductions in LBPI.

Soft Tissue Manipulation Alters RANTES/CCL5 and IL-4 Cytokine Levels in a Rat Model of Chronic Low Back Pain

Low back pain (LBP) is a common musculoskeletal complaint that can impede physical function and mobility. Current management often involves pain medication, but there is a need for non-pharmacological and non-invasive interventions. Soft tissue manipulation (STM), such as massage, has been shown to be effective in human subjects, but the molecular mechanisms underlying these findings are not well understood. In this paper, we evaluated potential changes in the soft tissue levels of more than thirty pro- or anti-inflammatory cytokines following instrument-assisted STM (IASTM) in rats with chronic, induced LBP using Complete Freund's Adjuvant. Our results indicate that IASTM is associated with reduced soft tissue levels of Regulated on Activation, Normal T cell Expressed and Secreted (RANTES)/Chemokine (C-C motif) ligand 5 (CCL5) and increased soft tissue levels of Interleukin (IL)-4, which are pro-inflammatory and anti-inflammatory factors, respectively, by 120 min post-treatment. IASTM was not associated with tissue-level changes in C-X-C Motif Chemokine Ligand (CXCL)-5/Lipopolysaccharide-Induced CXC Chemokine (LIX)-which is the murine homologue of IL-8, CXCL-7, Granulocyte-Macrophage-Colony Simulating Factor (GM-CSF), Intercellular Adhesion Molecule (ICAM)-1, IL1-Receptor Antagonist (IL-1ra), IL-6, Interferon-Inducible Protein (IP)-10/CXCL-10, L-selectin, Tumor Necrosis Factor (TNF)-α, or Vascular Endothelial Growth Factor (VEGF) at either 30 or 120 min post-treatment. Combined, our findings raise the possibility that IASTM may exert tissue-level effects associated with improved clinical outcomes and potentially beneficial changes in pro-/anti-inflammatory cytokines in circulation and at the tissue level.

Sigma-1 receptor expression in a subpopulation of lumbar spinal cord microglia in response to peripheral nerve injury

Sigma-1 Receptor has been shown to localize to sites of peripheral nerve injury and back pain. Radioligand probes have been developed to localize Sigma-1 Receptor and thus image pain source. However, in non-pain conditions, Sigma-1 Receptor expression has also been demonstrated in the central nervous system and dorsal root ganglion. This work aimed to study Sigma-1 Receptor expression in a microglial cell population in the lumbar spine following peripheral nerve injury. A publicly available transcriptomic dataset of 102,691 L4/5 mouse microglial cells from a sciatic-sural nerve spared nerve injury model and 93,027 age and sex matched cells from a sham model was used. At each of three time points-postoperative day 3, postoperative day 14, and postoperative month 5-gene expression data was recorded for both spared nerve injury and Sham cell groups. For all cells, 27,998 genes were sequenced. All cells were clustered into 12 distinct subclusters and gene set enrichment pathway analysis was performed. For both the spared nerve injury and Sham groups, Sigma-1 Receptor expression significantly decreased at each time point following surgery. At the 5-month postoperative time point, only one of twelve subclusters showed significantly increased Sigma-1 Receptor expression in spared nerve injury cells as compared to Sham cells (p = 0.0064). Pathway analysis of this cluster showed a significantly increased expression of the inflammatory response pathway in the spared nerve injury cells relative to Sham cells at the 5-month time point (p = 6.74e-05). A distinct subcluster of L4/5 microglia was identified which overexpress Sigma-1 Receptor following peripheral nerve injury consistent with neuropathic pain inflammatory response functioning. This indicates that upregulated Sigma-1 Receptor in the central nervous system characterizes post-acute peripheral nerve injury and may be further developed for clinical use in the differentiation between low back pain secondary to peripheral nerve injury and low back pain not associated with peripheral nerve injury in cases where the pain cannot be localized.

Chronic pain after spine surgery: Insights into pathogenesis, new treatment, and preventive therapy

Chronic pain after spine surgery (CPSS) is often characterized by intractable low back pain and/or radiating leg pain, and has been reported in 8-40% of patients that received lumbar spine surgery. We conducted a literature search of PubMed, MEDLINE/OVID with a focus on studies about the etiology and treatments of CPSS and low back pain. Our aim was to provide a narrative review that would help us better understand the pathogenesis and current treatment options for CPSS. This knowledge will aid in the development of optimal strategies for managing postoperative pain symptoms and potentially curing the underlying etiologies. Firstly, we reviewed recent advances in the mechanistic study of CPSS, illustrated both structural (e.g., fibrosis and scaring) and non-structural factors (e.g., inflammation, neuronal sensitization, glial activation, psychological factor) causing CPSS, and highlighted those having not been given sufficient attention as the etiology of CPSS. Secondly, we summarized clinical evidence and therapeutic perspectives of CPSS. We also presented new insights about the treatments and etiology of CPSS, in order to raise awareness of medical staff in the identification and management of this complex painful disease. Finally, we discussed potential new targets for clinical interventions of CPSS and future perspectives of mechanistic and translational research. CPSS patients often have a mixed etiology. By reviewing recent findings, the authors advocate that clinicians shall comprehensively evaluate each case to formulate a patient-specific and multi-modal pain treatment, and importantly, consider an early intraoperative intervention that may decrease the risk or even prevent the onset of CPSS.

Translational potential statement

CPSS remains difficult to treat. This review broadens our understanding of clinical therapies and underlying mechanisms of CPSS, and provides new insights which will aid in the development of novel mechanism-based therapies for not only managing the established pain symptoms but also preventing the development of CPSS.