Is the Agricultural Work a Risk Factor for Koreans Elderly Spinal Sagittal Imbalance?

Lumbar fusion surgery in the era of an aging society: analysis of a nationwide population cohort with minimum 8-year follow-up

BACKGROUND CONTEXT

Fusions for lumbar spine diseases are widely performed and have a growing incidence, especially in elderly population.

PURPOSE

The goal of this study was to assess national trends of lumbar spinal fusions and examine the risk for reoperations after a lumbar fusion with a focus on 'epidemiologic transition' relating to age.

STUDY DESIGN/SETTING

The prospectively collected Korean Health Insurance Review and Assessment Service (HIRA) nationwide cohort database was retrospectively reviewed.

PATIENT SAMPLE

The total 278,815 patients who underwent lumbar spinal fusions for degenerative spine diseases between 2010 and 2018 were reviewed and used to assess trends in operative incidence. The 37,050 patients who underwent lumbar fusions between 1/2010 and 12/2011 were enrolled to determine 8-year reoperation rates.

OUTCOME MEASURES

The overall number of lumbar spinal fusions were analyzed for the national annual trend. Demographic data, reoperation rates, and confounding clinical factors were evaluated.

METHODS

The overall number of lumbar spinal fusions was analyzed to determine the national annual trend of operative incidence. For the reoperation rate analysis, the primary outcome measured was the cumulative incidence of revision operations within a minimum 8-year follow-up period. Additional outcomes included comparative analyses of the reoperation rate with respect to age, sex, or other underlying comorbidities.

RESULTS

Over time, elderly patients comprised a larger portion of the cohort (2010:24.2%; 2018:37.6%), while operations in younger patients decreased over time (2010:40.3%; 2018:27.0%). In the cohort of patients with a minimum 8-year follow-up (n=37,050), rates of reoperation peaked in patients aged 60-69 years (17.6 per 1000 person-years [HR 2.20 compared to <40years]) and decreased for more elderly patients (14.3 per 1000 person-years [HR 1.80 compared to <40years]). Age was the most significant risk factor for reoperation. Osteoporosis was also a risk factor for reoperation in postmenopausal females.

CONCLUSIONS

Increasing incidence of lumbar fusions in elderly patients was seen however the risk of reoperation decreased in patients aged 70 or more. Lumbar fusion for elderly patients should not be hesitated in the decision-making process because of concerns about reoperation.

The Relationship Between Low Back Pain and Sagittal Spinal Alignment and Back Muscle Mass in Korean Fishery Workers

OBJECTIVE

To investigate the relationship between low back pain (LBP) and sagittal spino-pelvic parameters along with the relationship between LBP and back muscle mass in Korean male and female fishery workers.

METHODS

This retrospective study included a total of 146 subjects who underwent Fishermen's health survey conducted between June 2018 and August 2020. LBP was evaluated through visual analogue scale (VAS) and Oswestry Disability Index (ODI). Sagittal spino-pelvic parameters were measured from whole spine standing X-rays. Back muscle cross-sectional areas were identified through lumbar spine magnetic resonance imaging and body composition was analyzed through bioelectrical impedance analysis.

RESULTS

The study included 75 males and 71 females, with an average age of 58.33 years for males and 56.45 years for females. Female subjects exhibited higher VAS and ODI scores, larger pelvic tilt (PT) and trunk fat mass and smaller trunk muscle mass compared to males. In female, ODI positively correlated with sagittal vertical axis (SVA) and PT. No significant correlations were found between ODI scores and body composition in either sex. The high ODI group showed greater SVA, PT, and pelvic incidence-lumbar lordosis and higher trunk fat/muscle ratio. Psoas muscle mass, total and skeletal muscle mass and trunk muscle mass of that group were smaller than those of low ODI group.

CONCLUSION

Spino-pelvic parameters and back muscle mass were associated with ODI and there were differences between Korean male and female fishery workers.

Biomechanical Effects of Different Sitting Postures and Physiologic Movements on the Lumbar Spine: A Finite Element Study

This study used the finite element method(FEM) to investigate how pressure on the lumbar spine changes during dynamic movements in different postures: standing, erect sitting on a chair, slumped sitting on a chair, and sitting on the floor. Three load modes (flexion, lateral bending, and axial rotation) were applied to the FEM, simulating movements of the lumbar spine. Results showed no significant difference in pressure distribution on the annulus fiber and nucleus pulposus, representing intradiscal pressure, as well as on the cortical bone during movements between standing and erect sitting postures. However, both slumped sitting on a chair and sitting on the floor postures significantly increased pressure on the nucleus pulposus, annulus fibrosus, and cortical bone in all three movements when compared to standing or erect sitting on a chair. Notably, sitting on the floor resulted in even higher pressure on the nucleus pulposus and annulus fibers compared to slumped sitting on a chair. The decreased lumbar lordosis while sitting on the floor led to the highest increase in pressure on the annulus fiber and nucleus pulposus in the lumbar spine. In conclusion, maintaining an erect sitting position with increased lumbar lordosis during seated activities can effectively reduce intradiscal pressure and cortical bone stress associated with degenerative disc diseases and spinal deformities.

A Comparison of Spinopelvic Alignment and Quality of Life between Farmers and Non-Farmers: A Cross-Sectional Population-Based Study in a Japanese Rural Area

BACKGROUND

It may be difficult to define what would constitute an abnormal spinal sagittal alignment. The same degree of malalignment may be found both in patients with pain and disability and in asymptomatic individuals. This study focuses on elderly farmers who characteristically have a kyphotic spine, in addition to local residents. It questions whether these patients experience cervical and lower back symptoms, respectively, more often than elderly people who never worked on a farm and do not have a kyphotic deformity. Previous research could have been biased by sampling patients who came to a spine clinic for treatment, whereas this study sampled asymptomatic elderly who may or may not have had kyphosis.

METHODS

We studied 100 local residents at their annual health checkup (22 farmers and 78 non-farmers) with a median age of 71 years (range 65-84 years). Spinal radiographs were used to measure sagittal vertical axis, lumbar lordosis, thoracic kyphosis and other measurements of sagittal malalignment. Back symptoms were measured using Oswestry Disability Index (ODI) and Neck Disability Index (NDI). The association between alignment measures and back symptoms were calculated by bivariate comparison between patient groups and by Pearson's correlation.

RESULTS

About 55% of farmers and 35% of non-farmers had abnormal radiographs (i.e., vertebral fracture). Farmers had higher measurements of sagittal vertical axis (SVA), compared to non-farmers, when measured from C7 (median 24.4 mm vs. 9.15 mm, p = 0.04) and from C2 (47.65 vs. 25.3, p = 0.03). Lumbar lordosis (LL) and thoracic kyphosis (TK) were significantly decreased in farmers vs. non-farmers (37.5 vs. 43.5, p = 0.04 and 32.5 vs. 39, p = 0.02, respectively). The ODI was likely to be higher among farmers compared to non-farmers while NDI scores showed no significant difference between farmers and non-farmers (median 11.7 vs. 6.0, p = 0.06 and median 13 vs. 12, p = 0.82, respectively). In terms of correlation among spinal parameters, LL had a higher correlation with SVA, but TK had less correlation with SVA among farmers compared to non-farmers. There was no significant correlation between disability scores and measurements of sagittal alignment.

CONCLUSIONS

Farmers had higher measurements of sagittal malalignment, characterized by loss of LL, decreased TK and an increased forward translation of cervical vertebrae relative to sacrum. ODI was likely to higher in farmers compared to non-farmers although the association did not reach a significant level. These results probably indicate that the gradual development of spinal malalignment in agricultural workers does not result in excess morbidity compared to controls.

Radiographic hand osteoarthritis in women farmers: characteristics and risk factors

Background

Repetitive hand use increases the risk of hand osteoarthritis (OA). This study aimed to investigate characteristics of and risk factors for hand OA in Korean women farmers.

Methods

This cross-sectional study included women farmers resident in Jeollanam-do, Korea. The participants were interviewed, and radiographs were taken of both hands. Radiological hand OA was defined based on the Osteoarthritis Research Society International imaging criteria of joint space narrowing or the presence of osteophytes. The participants were divided into age groups of < 60 and ≥ 60 years. Obesity was defined as body mass index of > 25 kg/m². Annual working time was divided into < 2,000, 2,000–2,999, and ≥ 3,000 hours. Agricultural working type was divided into rice farming and field farming. Robust Poisson regression was used to identify factors associated with radiographic hand OA, with adjustment for age, obesity, annual working time, and agricultural classification.

Results

A total of 310 participants with a mean age of 58.1 ± 7.6 years, were enrolled. The prevalence of radiologically confirmed OA was 49.0%, with an OA prevalence of 39.4% the interphalangeal joint in the thumb (IP1). The prevalence of OA was higher in the distal interphalangeal joint than in the proximal interphalangeal, metacarpophalangeal, and carpometacarpal joints. The prevalence of OA varied by age, annual working time, and agriculture type.

Conclusions

Korean women farmers have a high prevalence of OA, particularly in the IP1 joints. OA is associated with age, working hours, and agriculture type.

Vitamin D Status and Bone Health in Postmenopausal Women Working in Greenhouses

Objectives

Greenhouse workers synthesize less vitamin D because ultraviolet light is blocked by the vinyl that covers the greenhouses. This study aimed to investigate the vitamin D status and bone health of postmenopausal women working in greenhouses.

Methods

This observational study enrolled women living in urban (n = 70, group 1) and rural areas (n = 91, group 2) and those working in greenhouses (n = 112, group 3). Serum levels of total and bioavailable 25-hydroxy-vitamin D [25(OH)D] and vitamin D binding protein were measured. T-scores of the lumbar spine and femur neck were measured by dual-energy X-ray absorptionetry.

Results

Heights were shorter in group 2 and group 3 than in group 1. Bioavailable 25(OH)D levels were higher and T-scores of the spine and femur were lower in both group 2 and 3 than in group 1. T-scores of the femur in group 3 were lower than those in group 2. The linear regression analysis showed that levels of bioavailable 25(OH)D significantly correlated with the spine T-scores but not with the femur T-scores. The prevalence of spinal osteoporosis was higher in both groups 2 and 3 compared to group 1. Group 3 demonstrated greater femur osteoporosis compared to groups 1 and 2.

Conclusions

Vitamin D plays an important role in spinal bone health. Moreover, working conditions are likely to play an important role in femur bone health. Therefore, appropriate working conditions and nutrition are paramount to improve bone health in postmenopausal women working in greenhouses.

Thoracolumbar Slope Is Useful Parameter for Evaluating HealthRelated Quality of Life and Sagittal Imbalance Aggravation in Adult Spinal Deformity: A Prospective Observational Cohort Study

Objective

The purpose of the present study was to evaluate the natural course of primary degenerative sagittal imbalance (PDSI), its aggravating factors, and health-related quality of life (HRQoL) associated with various spinal alignment parameters (SAPs) in patients with PDSI who have not undergone surgery.

Methods

One hundred three participants volunteered to participate. The SAPs, including T1 pelvic angle (T1PA), thoracolumbar tilt, and thoracolumbar slope (TLS), were measured on whole-spine standing radiographs. The back and lumbar muscle volumes were measured. To determine HRQoL at baseline and at 2-year follow-up, face-to-face questionnaires were administered, which included visual analogue scale of the back and leg, physical component summary/mental component summary of 36-item Short Form Health Survey, Oswestry Disability Index (ODI), and Mini-Mental State Examination.

Results

Overall HRQoL measures had improved after 2 years of follow-up compared to baseline. PDSI aggravation was observed in 18 participants (26.1%). TLS, sagittal vertical axis (SVA), and T1PA were strongly correlated with each other. TLS, SVA, and T1PA were correlated with ODI score. Among them, TLS was most highly correlated with ODI score. TLS greater than -3.5° was a predicting factor for PDSI aggravation (p=0.034; 95% confidence interval, 1.173–63.61; odds ratio, 8.636).

Conclusion

The present study implied that PDSI does not necessarily worsen with aging. TLS is an appropriate parameter for assessing the clinical situation in patients with PDSI. Furthermore, a TLS greater than -3.5° predicts PDSI aggravation; thus, TLS may be a useful parameter for predicting prognosis in PDSI.

Clinical, Radiographic, and Genetic Analyses in a Population-Based Cohort of Adult Spinal Deformity in the Older Population

OBJECTIVE

This study aimed to identify the sagittal parameters associated with health-related quality of life and genetic variations that increase the risk of adult spinal deformity (ASD) onset in the older population.

METHODS

We recruited 120 participants who had a sagittal vertical axis > 50 mm in a sagittal imbalance study. Sagittal radiographic parameters, cross-sectional area, and intramuscular fatty infiltration using the Goutallier classification in the paraspinal lumbar muscles were evaluated. Functional scales included the self-reported Oswestry Disability Index (ODI), 36-item Short Form Health Survey (SF-36), and visual analogue scales (VAS) for back and leg pain. We performed whole-exome sequencing and an exome-wide association study using the 100 control subjects and 63 individuals with severe phenotypes of sagittal imbalance.

RESULTS

Pelvic incidence minus lumbar lordosis (PI-LL) mismatch was negatively associated with the SF-36 and positively correlated with ODI and VAS for back and leg pain. PI-LL was related to the quality and size of the paraspinal muscles, especially the multifidus muscle. We identified common individual variants that reached exome-wide significance using single-variant analysis. The most significant single-nucleotide polymorphism was rs78773460, situated in an exon of the SVIL gene (odds ratio, 9.61; p = 1.15 × 10-9).

CONCLUSION

Older age, higher body mass index, and a more significant PI-LL mismatch were associated with unfavorable results on functional scales. We found a genetic variation in the SVIL gene, which has been associated with the integrity of the cytoskeleton and the development of skeletal muscles, in severe ASD phenotypes. Our results help to elucidate the pathogenesis of ASD.