Physical activity as mediator between back pain and disability.

The objective was to explore the mediating role of leisure-time physical activity on the correlation between back pain and disability. A mediation analysis was conducted among the cross-sectional sample of 1330 patients in outpatient clinic. The average age was 47.6 years and 64% were women. For the entire sample, the mediating effect of physical activity remained below 10% of the total effect. The mediating effect was significantly greater among women comparing to men - up to 19.0% [95% confidence interval (CI) 10.4-27.6%] versus 2.3% (95% CI 0.0-6.1%). The effect did not significantly differ based on age, BMI, or educational or professional status. Some insignificant trends, however, could be seen - the effect was possibly stronger among patients with higher educational level and those with higher BMI. The results suggested that while physical activity seems to be a weak mediator, its mediating role might vary across different groups of patients with back pain. This variation should be taken into account when planning rehabilitation measures for people with back pain.

Disability and pain after anterior cervical decompression and fusion: A group-based trajectory analysis.

OBJECTIVES: This study aimed to identify the clusters of patients with different developmental trajectories of pain and disability after anterior cervical decompression and fusion (ACDF). METHODS: Group-based trajectory analysis among 318 patients undergoing the ACDF. RESULTS: Three developmental trajectories of disability were identified: "Steadily good functioning," "Improved functioning," and "Steadily poor functioning." Three developmental trajectories of neck pain were identified: "Worsened pain," "Pain relief," and "Steadily severe pain." Two developmental trajectories of arm pain were identified: "Decreased arm pain" and "Severe arm pain with only short-term relief." No associations were found between sex, preoperative pain duration, or body weight and probability to be classified into a particular disability trajectory group. Female sex (relative risk ratio (RRR) 1.78) and longer history of preoperative pain (RRR 2.31-2.68) increased the probability to be classified into a group with steadily severe neck pain. Longer history of preoperative pain increased the probability to be classified into group with severe arm pain with only short-term pain relief (RRR 2.68). CONCLUSION: After the ACDF, dissimilar developmental trajectories of pain and disability were identified between the patient clusters. While sex, preoperative pain duration, and body weight were not associated with differences in improvement in disability level, female sex and longer duration of preoperative pain were correlated with more severe neck and arm pain after surgery.

Back pain and radicular pain after lumbar microdiscectomy.

PURPOSE: It is generally expected that lumbar microdiscectomy affects radicular leg pain, but not so much local back pain. The primary objective was to evaluate if the trajectories of changes in pain severity follow similar patterns for back and radicular leg pain after lumbar microdiscectomy. The secondary objective was to investigate the associations between some preoperative parameters and the patterns of these trajectories. METHODS: Register-based retrospective study of 353 patients undergoing microdiscectomy in the lumbar spine. Linear mixed modelling was applied. RESULTS: The average age of the participants was 46 years and 44% were women. The developmental trajectories were similar for both back and leg pain. Pain level decrease during the first year after the surgery, slightly worsening later. No statistically significant interactions were detected of preoperative pain duration or severity, sex or age on the shapes of the trajectories. For every analyzed grouping factor, the 95% confidence intervals overlapped at every postoperative time point with one exception - worse preoperative back pain was statistically significantly associated with worse pain at three months and at the end of the two-year follow-up. CONCLUSION: After microsurgical discectomy, developmental curves for both back and radicular leg pain demonstrated similar patterns. Pain intensity decreased during the first year after the surgery. and slightly increased after that remaining, however, below the preoperative level. Age, sex, preoperative pain duration or preoperative intensity of leg pain were not associated with significant differences in the trajectories of pain severity after the surgery. In this study, severe preoperative back pain was the only factor, which was significantly associated with worse postoperative trajectory of pain intensity.

Importance of factors determining disability caused by neck pain may vary by gender and age.

The objective was to investigate if age and gender affect the importance of domains of functioning when grading disability related to neck pain. Multi-group confirmatory factor analysis of register-based data on 392 patients undergoing cervical surgery was applied. The main outcome was item loadings on a common factor. The mean age was 55 years and 52% were women. The factor structure was different for both gender and age groups, P < 0.0001. Reading, driving, pain intensity, and recreational activity had the highest loadings while headaches, lifting, and sleep placed the lowest. Reading and pain intensity had bigger weight among men than women, while recreational activity and driving had higher loadings in women. Reading and work were more important for the younger than for the older respondents, while recreational activity was more important for the older respondents. The importance of factors determining disability caused by neck pain may vary by gender and age.

Change in functioning profile after cervical surgery.

The objectives are to (a) introduce an approach to use the Neck Disability Index (NDI) in a way, which is different and more International Classification of Functioning, Disability and Health-oriented than acommon practice - focusing on functional profile instead of composite score only, and (b) to describe the changes in functioning experienced by patients undergoing cervical surgery. This was a register-based study of almost 400 patients undergoing different cervical surgical procedures in a university hospital between 2018 and 2021. The patients responded to repeated surveys preoperatively and 3, 12 and 24 months postoperatively. Linear regression test was performed to analyze the change of the NDI score. The changes in scores during a follow-up were statistically significant ( P < 0.001) for all the NDI items as well as for the total score. Each item demonstrated significant improvement postoperatively and a slight worsening between 1 and 2 years after the surgery. The observed slight decline in functioning at the end of follow-up remained below the baseline level for all the items. While the change in the composite score of the NDI was able to describe the overall change in functioning after the surgery, different areas of functioning were affected by the surgery differently. The results suggest that the use of functional profiles, in addition to composite scores, is justified among patients with cervical pathologies.

Sex-related differential item functioning of neck disability index.

PURPOSE: To investigate if the responses to the Neck Disability Index (NDI) may produce some differential item functioning (DIF) comparing men and women. MATERIALS AND METHODS: Register-based study among patients undergoing cervical surgery. Item response theory (IRT) analysis including a model for detecting a DIF. RESULTS: Of 338 patients, 171 (51%) were women and 167 (49%) were men. The mean age was 54.0 years. For most of the items, the average level of disability in a studied sample was associated with the middle point of the scale. The ability to distinguish people with different levels of disability was high or perfect for seven out of 10 items. While the DIF could be seen for all 10 items, only three items demonstrated statistically significant DIF - "pain intensity", "headaches" and "recreation". While the other seven items did not show statistically significant DIFs, better discrimination (steeper curves) for women could be graphically observed for "personal care", "lifting", "work", "driving" and "sleeping". CONCLUSIONS: It seemed that the NDI may behave differently depending on the sex of respondents. Several items of the NDI may be more precise and more sensitive when detecting restrictions in functioning among women compared to men. This finding should be taken into account when using the NDI in research and clinical practice.Implications for RehabilitationWhile the Neck Disability Index have been found to be a reliable and valid scale, potential differences in its properties across different sexes have mostly remained uninvestigated.This study showed that the Neck Disability Index may behave differently depending on the sex of respondents.Several items of the Neck Disability Index were more precise and sensitive when detecting restrictions in functioning among women compared to men.This difference should be taken into account when using the NDI in research and clinical practice.

Reliability and validity of the Neck Disability Index among patients undergoing cervical surgery.

To explore the internal consistency and factor structure of the Neck Disability Index (NDI) among patients undergoing surgery on the cervical spine. This was an observational retrospective cohort study among 392 patients undergoing cervical surgery of any kind in a university hospital between 2018 and 2021. The patients responded to repeated surveys preoperatively, and 3, 12 and 24 months postoperatively. The reliability and validity of the NDI were investigated using Cronbach's alpha and factor analysis. The internal consistency of the NDI was found to be good at 0.86. The exploratory factor analysis demonstrated unidimensionality. The correlations between the main factor 'disability' and all the individual items of the NDI were at least moderate. The highest correlations were observed for pain intensity, reading, driving and recreation. The NDI is an internally consistent and unidimensional scale when applied to a population of patients undergoing cervical surgery. 45: 273-278 Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.