Risk factors for sciatica leading to hospitalization

Associations of socioeconomic and lifestyle characteristics, psychological symptoms, multimorbidity, and multisite pain with sciatica - a 15-year longitudinal study

BACKGROUND CONTEXT

Sciatica is defined as pain radiating from the low back to the leg, usually below the knee. It is a disabling condition that causes a major burden to health care and society. Previous evidence of the multifactorial etiology of sciatica comes mostly from cross-sectional studies. Larger, longitudinal studies with a multidimensional set of variables are needed.

PURPOSE

To examine how socioeconomic and lifestyle characteristics, psychological symptoms, multimorbidity, and multisite pain are associated with sciatica.

STUDY DESIGN

A longitudinal study of the Northern Finland Birth Cohort 1966.

PATIENT SAMPLE

In total 6,683 working-aged members of the Northern Finland Birth Cohort 1966.

OUTCOME MEASURES

Self-reported sciatic pain status over a 15-year study period.

METHODS

We conducted a 15-year longitudinal study from the age of 31 to 46. We used multivariable generalized estimation equations analysis to examine how socioeconomic characteristics (low education, unemployment, and living alone), lifestyle characteristics (overweight, obesity, current smoking, and physical inactivity), psychological symptoms (depression, anxiety), multimorbidity, and multisite pain were associated with sciatica.

RESULTS

At the age of 31, 21.1% of the study population reported sciatic pain and at the age of 46, 36.7%. Multisite pain was clearly the strongest factor associated with sciatica (odds ratio [OR] 2.61, 95% confidence interval [CI] 2.34‒2.92). In descending order of effect size, older age, low education, psychological symptoms, multimorbidity, overweight, obesity, physical inactivity and current smoking were positively associated with sciatica. Their ORs varied between 1.17 and 2.18. Living alone was negatively associated with sciatica (OR 0.81, 95% CI 0.72‒0.90).

CONCLUSIONS

Multisite pain had the strongest association with sciatica. The effect sizes of the other factors were clearly smaller. To our knowledge this is the first study to evaluate the association of multisite pain with sciatica. This finding may have considerable implications for clinical work treating patients with sciatica.

Causal association of physical activity with low back pain, intervertebral disc degeneration and sciatica: a two-sample mendelian randomization analysis study

Objective: Previous studies are insufficient to confirm a causal association between physical activity (PA) and low back pain (LBP), intervertebral disc degeneration (IDD), and sciatica. The present study used a two-sample Mendelian randomization (MR) analysis method to demonstrate whether or not there was a causal connection. Methods: First, four PA phenotypes were selected [accelerometer-based PA (average acceleration), accelerometer-based PA (acceleration fraction >425 mg), self-reported moderate-to-vigorous PA, and self-reported vigorous PA], setting thresholds for single nucleotide polymorphisms (SNPs) significantly concerned with PA p < 5 × 10-8, linkage disequilibrium (LD) r 2 < 0.01, genetic distance >5,000 kb, and F-value >10. SNPs associated with the outcome and confounding factors were then excluded using the PhenoScanncer database. Finally, after coordinating the genetic instruments from genome-wide association studies (GWAS) effect alleles for exposure and outcomes, multiplicative random effects inverse variance weighting (IVW), MR-Egger, weighted median method (WMM), and weighted mode method were used to assess exposure-outcome causality and perform sensitivity analysis on the estimated results. Results: The current study's IVW findings revealed proof of a causal connection between PA and LBP. While there was a positive causal tie between accelerometer-based PA (acceleration fraction >425 mg) and LBP [OR: 1.818, 95% CI:1.129-2.926, p = 0.012], there was a negative causal link between accelerometer-based PA (average acceleration) and LBP [OR: 0.945, 95% CI: 0.909-0.984, p = 0.005]. However causal relationship between PA and IDD or sciatica was not found. Conclusion: Increasing average PA but needing to avoid high-intensity PA may be an effective means of preventing low back pain. Although PA is not directly causally related to disc degeneration and sciatica, it can act through indirect pathways.

Systematic review of predictors of hospitalisation for non-specific low back pain with or without referred leg pain

Significant costs and utilisation of healthcare resources are associated with hospitalisations for non-specific low back pain despite clinical guidelines recommending community-based care. The aim of this systematic review was to investigate the predictors of hospitalisation for low back pain. A protocol was registered with PROSPERO international prospective register of systematic reviews (#CRD42021281827) and conducted in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement. Database search of Ovid Medline, Emcare, Embase, PsycINFO, Cochrane Library, PEDro and OTSeeker was conducted. Studies were included if they examined a predictor of hospitalisation for non-specific low back pain with or without referred leg pain. Data was extracted and descriptively synthesised. Risk of bias of included studies was assessed using the Critical Appraisal Skills Programme Checklists. There were 23 studies published over 29 articles which identified 52 predictor variables of hospitalisation for low back pain. The risk of hospitalisation was grouped into themes: personal, health and lifestyle, psychology, socioeconomic, occupational, clinical, and health systems and processes. There was moderate level evidence that arrival to an emergency department via ambulance with low back pain, and older age increase the risk of hospitalisations for low back pain. There was low level evidence that high pain intensity, past history of low back pain, opioid use, and occupation type increase the risk of hospitalisation for low back pain. Further research into psychological and social factors is warranted given the paucity of available studies. Hospital avoidance strategies, improved patient screening and resource utilisation in emergency departments are considerations for practice.

Analysis of the influence of species, intervertebral disc height and Pfirrmann classification on failure load of an injured disc using a novel disc herniation model

BACKGROUND CONTEXT

Annular repair devices offer a solution to recurrent disc herniations by closing an annular defect and lowering the risk of reherniation. Given the significant risk of neurologic injury from device failure it is imperative that a reliable preclinical model exists to demonstrate a high load to failure for the disc repair devices.

PURPOSE

To establish a preclinical model for disc herniation and demonstrate how changes in species, intervertebral disc height and Pfirrmann classification impacts failure load on an injured disc. We hypothesized that: (1) The force required for disc herniation would be variable across disc morphologies and species, and (2) for human discs the force to herniation would inversely correlate with the degree of disc degeneration.

STUDY DESIGN

Animal and human cadaveric biomechanical model of disc herniation.

METHODS

We tested calf lumbar spines, bovine tail segments and human lumbar spines. We first divided individual lumbar or tail segments to include the vertebral bodies and disc. We then hydrated the specimens by placing them in a saline bath overnight. A magnetic resonance images were acquired from human specimens and a Pfirrmann classification was made. A stab incision measuring 25% of the diameter of the disc was then done to each specimen along the posterior intervertebral disc space. Each specimen was placed in custom test fixtures on a servo-hydraulic test frame (MTS, Eden Prarie, MN) such that the superior body was attached to a 10,000 lb load cell and the inferior body was supported on the piston. A compressive ramping load was placed on the specimen in load control at 4 MPa/sec stopping at 75% of the disc height. Load was recorded throughout the test and failure load calculated. Once the test was completed each specimen was sliced through the center of the disc and photos were taken of the cut surface.

RESULTS

Fifteen each of calf, human, and bovine tail segments were tested. The failure load varied significantly between specimens (p<.001) with human specimens having the highest average failure load (8154±2049 N). Disc height was higher for lumbar/bovine tail segments as compared to calf specimens (p<.001) with bovine tails having the highest disc height (7.1±1.7 mm). Similarly, human lumbar discs had a cross sectional area that was greater than both bovine tail/calf lumbar spines (p<.001). There was no correlation between disc height and failure load within each individual species (p>.05). Cross sectional area and failure load did not correlate with failure load for human lumbar spine and bovine tails (p>.05) but did correlate with calf spine (r=0.53, p=.04). There was a statistically significant inverse correlation between disc height and Pfirrmann classification for human lumbar spines (r=-0.84, p<.001). There was also a statistically significant inverse relationship between Pfirrmann classification and failure load (r=-0.58, p=.02).

CONCLUSIONS

We have established a model for disc herniation and have shown how results of this model vary between species, disc morphology, and Pfirrmann classification. Both hypotheses were accepted: The force required for disc herniation was variable across species, and the force to herniation for human spines was inversely correlated with the degree of disc degeneration. We recommend that models using human intervertebral discs should include data on Pfirrmann classification, while biomechanical models using calf spines should report cross sectional area. Failure loads do not vary based on dimensions for bovine tails.

CLINICAL SIGNIFICANCE

Our analysis of models for disc herniation will allow for quicker, reliable comparisons of failure forces required to induce a disc herniation. Future work with these models may facilitate rapid testing of devices to repair a torn/ruptured annulus.

Nicotine dependence and the International Association for the Study of Pain neuropathic pain grade in patients with chronic low back pain and radicular pain: is there an association?

Background

This study investigated whether current smoking and a higher nicotine dependency were associated with chronic low back pain (LBP), lumbar related leg pain (sciatica) and/or radicular neuropathic pain.

Methods

A cross-sectional study was conducted on 150 patients (mean age, 60.1 ± 13.1 yr). Demographic data, the International Association for the Study of Pain (IASP) neuropathic pain grade, STarT Back tool, and the Fagerström test were completed. A control group (n = 50) was recruited.

Results

There was a significant difference between current smokers and non-smokers in the chronic LBP group in the mean pain score (P = 0.025), total STarT Back score (P = 0.015), worst pain location (P = 0.020), most distal pain radiation (P = 0.042), and in the IASP neuropathic pain grade (P = 0.026). There was a significant difference in the mean Fagerström score between the four IASP neuropathic pain grades (P = 0.005). Current smoking yielded an odds ratio (OR) of 3.071 (P = 0.011) for developing chronic LBP and sciatica, and an OR of 4.028 (P = 0.002) for obtaining an IASP “definite/probable” neuropathic pain grade, for both cohorts. The likelihood for chronic LBP and sciatica increased by 40.9% (P = 0.007), while the likelihood for an IASP neuropathic grade of “definite/probable” increased by 50.8% (P = 0.002), for both cohorts, for every one unit increase in the Fagerström score.

Conclusions

A current smoking status and higher nicotine dependence increase the odds for chronic LBP, sciatica and radicular neuropathic pain.

Work-related risk factors for sciatica leading to hospitalization

The aim of this study was to assess the effects of the general strenuousness of work and various physical exposures on the risk of hospitalization for sciatica. The study population consisted of Finns aged 30 to 59 who had participated in a national health examination survey in 1978–80 (N = 3891). The participants were followed up until the end of 2011 and information on work-related determinants was acquired by a questionnaire. After adjustment for confounders, sedentary work involving handling fairly heavy objects/physically light work (HR 1.57; 95% CI 1.05–2.34), lifting or carrying heavy objects (2.10; 1.35–3.26) and exposure to whole-body vibration (1.61; 0.95–2.72) predicted sciatica, whereas heavier workloads appeared to reduce its risk (0.48; 0.26–0.89). There was an interaction between body mass index and exposure to whole-body vibration for the risk of sciatica. Overweight (1.94; 0.96–3.93) and obese (3.50; 1.44–8.46) participants exposed to whole-body vibration were at an increased risk of sciatica. Individuals of normal weight who were exposed to vibration, and overweight and obese individuals who were not exposed to vibration were not at an increased risk. The risk of hospitalization for sciatica seems to be highest among obese individuals exposed to whole-body vibration and among those lifting or carrying heavy objects.

The profile of chiropractors managing patients with low back-related leg pain: analyses of 1907 chiropractors from the ACORN practice-based research network

Background

Approximately 60% of people with low back pain also have associated leg pain symptoms. Guidelines for low back pain recommend non-pharmacological approaches, including spinal manipulation - a therapy provided by chiropractors. However, limited empirical data has examined the characteristics of chiropractors managing patients with low back-related leg pain (LBRLP). Our objective is to describe the prevalence, profile and practice characteristics of Australian chiropractors who often treat LBRLP, compared to those who do not often treat LBRLP.

Methods

This is a cross-sectional analysis of a nationally representative sample from the Australian Chiropractic Research Network (ACORN). This study investigated the demographic and practice characteristics as well as clinical management of chiropractors who ‘often’ treated patients with LBRLP compared to those who treated LBRLP ‘never/rarely/sometimes’. Multiple logistic regression models identified independent factors associated with chiropractors who ‘often’ treated patients with LBRLP.

Results

A total of 1907 chiropractors reported treating patients experiencing LBRLP, with 80.9% of them ‘often’ treating LBRLP. Chiropractors who ‘often’ treated LBRLP were more likely to manage patients with multi-site pain including axial low back pain (OR = 21.1), referred/radicular neck pain (OR = 10.8) and referred/radicular thoracic pain (OR = 3.1). While no specific management strategies were identified, chiropractors who ‘often’ treated LBRLP were more likely to discuss medication (OR = 1.8), manage migraine (OR = 1.7) and degenerative spine conditions (OR = 1.5), and treat women during pregnancy (OR = 1.6) and people with work-related injuries (OR = 1.5), compared to those not treating LBRLP frequently.

Conclusions

Australian chiropractors frequently manage LBRLP, although the nature of specific management approaches for this condition remains unclear. Further research on the management of LBRLP can better inform policy makers and educators interested in upskilling chiropractors to deliver safe and effective treatment of LBRLP.