Postoperative Dural Sac Cross-Sectional Area as an Association for Outcome After Surgery for Lumbar Spinal Stenosis: Clinical and Radiological Results From the NORDSTEN-Spinal Stenosis Trial.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: The aim was to investigate the association between postoperative dural sac cross-sectional area (DSCA) after decompressive surgery for lumbar spinal stenosis and clinical outcome. Furthermore, to investigate if there is a minimum threshold for how extensive a posterior decompression needs to be to achieve a satisfactory clinical result. SUMMARY OF BACKGROUND DATA: There is limited scientific evidence for how extensive lumbar decompression needs to be to obtain a good clinical outcome in patients with symptomatic lumbar spinal stenosis. MATERIALS AND METHODS: All patients were included in the Spinal Stenosis Trial of the NORwegian Degenerative spondylolisthesis and spinal STENosis (NORDSTEN)-study. The patients underwent decompression according to three different methods. DSCA measured on lumbar magnetic resonance imaging at baseline and at three months follow-up, and patient-reported outcome at baseline and at two-year follow-up were registered in a total of 393 patients. Mean age was 68 (SD: 8.3), proportion of males were 204/393 (52%), proportion of smokers were 80/393 (20%), and mean body mass index was 27.8 (SD: 4.2).The cohort was divided into quintiles based on the achieved DSCA postoperatively, the numeric, and relative increase of DSCA, and the association between the increase in DSCA and clinical outcome were evaluated. RESULTS: At baseline, the mean DSCA in the whole cohort was 51.1 mm 2 (SD: 21.1). Postoperatively the area increased to a mean area of 120.6 mm 2 (SD: 46.9). The change in Oswestry disability index in the quintile with the largest DSCA was -22.0 (95% CI: -25.6 to -18), and in the quintile with the lowest DSCA the Oswestry disability index change was -18.9 (95% CI: -22.4 to -15.3). There were only minor differences in clinical improvement for patients in the different DSCA quintiles. CONCLUSION: Less aggressive decompression performed similarly to wider decompression across multiple different patient-reported outcome measures at two years following surgery.

Amoxicillin Did Not Reduce Modic Change Edema in Patients With Chronic Low Back Pain: Subgroup Analyses of a Randomised Trial (the AIM Study).

STUDY DESIGN: Exploratory subgroup analyses of a randomised trial [Antibiotics in Modic changes (AIM) study]. OBJECTIVE: The aim was to assess the effect of amoxicillin versus placebo in reducing Modic change (MC) edema in patients with chronic low back pain. SUMMARY OF BACKGROUND DATA: The AIM study showed a small, clinically insignificant effect of amoxicillin on pain-related disability in patients with chronic low back pain and MC type 1 (edema type) on magnetic resonance imaging (MRI). MATERIALS AND METHODS: A total of 180 patients were randomised to receive 100 days of amoxicillin or placebo. MC edema was assessed on MRI at baseline and one-year follow-up. Per-protocol analyses were conducted in subgroups with MC edema on short tau inversion recovery (STIR) or T1/T2-weighted MRI at baseline. MC edema reductions (yes/no) in STIR and T1/T2 series were analyzed separately. The effect of amoxicillin in reducing MC edema was analyzed using logistic regression adjusted for prior disk surgery. To assess the effect of amoxicillin versus placebo within the group with the most abundant MC edema on STIR at baseline ("STIR3" group), we added age, STIR3 (yes/no), and STIR3×treatment group (interaction term) as independent variables and compared the marginal means (probabilities of edema reduction). RESULTS: Compared to placebo, amoxicillin did not reduce MC edema on STIR (volume/intensity) in the total sample with edema on STIR at baseline (odds ratio 1.0, 95% CI: 0.5, 2.0; n=141) or within the STIR3 group (probability of edema reduction 0.69, 95% CI: 0.47, 0.92 with amoxicillin and 0.61, 95% CI: 0.43, 0.80 with placebo; n=41). Compared with placebo, amoxicillin did not reduce MC edema in T1/T2 series (volume of the type 1 part of MCs) (odds ratio: 1.0, 95% CI: 0.5, 2.3, n=104). Edema declined in >50% of patients in both treatment groups. CONCLUSIONS: From baseline to one-year follow-up, amoxicillin did not reduce MC edema compared with placebo. LEVEL OF EVIDENCE: 2.

Apparent diffusion coefficient values in Modic changes - interobserver reproducibility and relation to Modic type.

BACKGROUND: Modic Changes (MCs) in the vertebral bone marrow were related to back pain in some studies but have uncertain clinical relevance. Diffusion weighted MRI with apparent diffusion coefficient (ADC)-measurements can add information on bone marrow lesions. However, few have studied ADC measurements in MCs. Further studies require reproducible and valid measurements. We expect valid ADC values to be higher in MC type 1 (oedema type) vs type 3 (sclerotic type) vs type 2 (fatty type). Accordingly, the purpose of this study was to evaluate ADC values in MCs for interobserver reproducibility and relation to MC type. METHODS: We used ADC maps (b 50, 400, 800 s/mm2) from 1.5 T lumbar spine MRI of 90 chronic low back pain patients with MCs in the AIM (Antibiotics In Modic changes)-study. Two radiologists independently measured ADC in fixed-sized regions of interests. Variables were MC-ADC (ADC in MC), MC-ADC% (0% = vertebral body, 100% = cerebrospinal fluid) and MC-ADC-ratio (MC-ADC divided by vertebral body ADC). We calculated mean difference between observers ± limits of agreement (LoA) at separate endplates. The relation between ADC variables and MC type was assessed using linear mixed-effects models and by calculating the area under the receiver operating characteristic curve (AUC). RESULTS: The 90 patients (mean age 44 years; 54 women) had 224 MCs Th12-S1 comprising type 1 (n = 111), type 2 (n = 91) and type 3 MC groups (n = 22). All ADC variables had higher predicted mean for type 1 vs 3 vs 2 (p < 0.001 to 0.02): MC-ADC (10- 6 mm2/s) 1201/796/576, MC-ADC% 36/21/14, and MC-ADC-ratio 5.9/4.2/3.1. MC-ADC and MC-ADC% had moderate to high ability to discriminate between the MC type groups (AUC 0.73-0.91). MC-ADC-ratio had low to moderate ability (AUC 0.67-0.85). At L4-S1, widest/narrowest LoA were for MC-ADC 20 ± 407/12 ± 254, MC-ADC% 1.6 ± 18.8/1.4 ± 10.4, and MC-ADC-ratio 0.3 ± 4.3/0.2 ± 3.9. Difference between observers > 50% of their mean value was less frequent for MC-ADC (9% of MCs) vs MC-ADC% and MC-ADC-ratio (17-20%). CONCLUSIONS: The MC-ADC variable (highest mean ADC in the MC) had best interobserver reproducibility, discriminated between MC type groups, and may be used in further research. ADC values differed between MC types as expected from previously reported MC histology.

Decompression with or without Fusion in Degenerative Lumbar Spondylolisthesis.

BACKGROUND: In patients with lumbar spinal stenosis and degenerative spondylolisthesis, it is uncertain whether decompression surgery alone is noninferior to decompression with instrumented fusion. METHODS: We conducted an open-label, multicenter, noninferiority trial involving patients with symptomatic lumbar stenosis that had not responded to conservative management and who had single-level spondylolisthesis of 3 mm or more. Patients were randomly assigned in a 1:1 ratio to undergo decompression surgery (decompression-alone group) or decompression surgery with instrumented fusion (fusion group). The primary outcome was a reduction of at least 30% in the score on the Oswestry Disability Index (ODI; range, 0 to 100, with higher scores indicating more impairment) during the 2 years after surgery, with a noninferiority margin of -15 percentage points. Secondary outcomes included the mean change in the ODI score as well as scores on the Zurich Claudication Questionnaire, leg and back pain, the duration of surgery and length of hospital stay, and reoperation within 2 years. RESULTS: The mean age of patients was approximately 66 years. Approximately 75% of the patients had leg pain for more than a year, and more than 80% had back pain for more than a year. The mean change from baseline to 2 years in the ODI score was -20.6 in the decompression-alone group and -21.3 in the fusion group (mean difference, 0.7; 95% confidence interval [CI], -2.8 to 4.3). In the modified intention-to-treat analysis, 95 of 133 patients (71.4%) in the decompression-alone group and 94 of 129 patients (72.9%) in the fusion group had a reduction of at least 30% in the ODI score (difference, -1.4 percentage points; 95% CI, -12.2 to 9.4), showing the noninferiority of decompression alone. In the per-protocol analysis, 80 of 106 patients (75.5%) and 83 of 110 patients (75.5%), respectively, had a reduction of at least 30% in the ODI score (difference, 0.0 percentage points; 95% CI, -11.4 to 11.4), showing noninferiority. The results for the secondary outcomes were generally in the same direction as those for the primary outcome. Successful fusion was achieved with certainty in 86 of 100 patients (86.0%) who had imaging available at 2 years. Reoperation was performed in 15 of 120 patients (12.5%) in the decompression-alone group and in 11 of 121 patients (9.1%) in the fusion group. CONCLUSIONS: In this trial involving patients who underwent surgery for degenerative lumbar spondylolisthesis, most of whom had symptoms for more than a year, decompression alone was noninferior to decompression with instrumented fusion over a period of 2 years. Reoperation occurred somewhat more often in the decompression-alone group than in the fusion group. (NORDSTEN-DS ClinicalTrials.gov number, NCT02051374.).

Predictors for long-term curve progression after Boston brace treatment of idiopathic scoliosis.

BACKGROUND: Identifying factors that predict successful bracing in patients with idiopathic scoliosis may help planning treatment. AIM: To assess predictors for long-term curve progression and health-related quality of life after Boston brace treatment. DESIGN: Observational retrospective cohort study with analysis of brace treated patients followed from start until at least 10 years after treatment. SETTING: Patients recruited from the country's entire population consecutively treated at the National Hospital. POPULATION: 365 patients (339 girls/26 boys) with idiopathic scoliosis. Mean (SD) chronological age/bone age at start bracing was 13.2 (1.9)/12.6 (1.9) years. The primary major curve measured 33.2 (7.4°), and the major levels were thoracic (N.=248), thoracolumbar (N.=78) and lumbar (N.=39). Mean bracing time was 2.8 (1.5) years. Long-term follow-up was in average 23.3 (4.1) years after weaning with a mean major curve of 33.0 (13.1°). Successful treatment was defined as a stable primary curve with progression ≤5°, and secondary the SRS-22 questionnaire assessed quality of life. METHODS: We applied linear or logistic regression with backward elimination. Internal validation was assessed by bootstrapping. Twelve variables were included in the prediction models: age, bone age, scoliosis in close family, major curve size, level, shape, flexibility and in-brace redressement, compliance, curve magnitude after 1 year, treatment time and quality of life (SRS-22). RESULTS: 290 patients (79%) had rated good compliance using the brace >20 hours daily. Treatment failure was observed in 65 patients (18%), and 27 of them were operated. The best baseline predictors were age and brace redressement. During treatment compliance, major curve after 1 year, and treatment time were the best predictors, while thoracic major curve, curve size at start bracing and scoliosis in close family also contributed to the final model. The model's ability to predict quality of life was low. CONCLUSIONS: The best predictors for a long-term success were good redressement and compliance, unchanged or reduced major curve after one year and short treatment time. CLINICAL REHABILITATION IMPACT: Predictors at baseline and during early treatment can help identifying patients who benefit from bracing.

Associations between shoulder pain and functioning on the ICF checklist and the disabilities of the arm, shoulder, and hand scale - a cross-sectional study.

Purpose: The association between patients' shoulder pain and functioning according to the International Classification of Functioning, Disability, and Health (ICF), and outcome on a condition specific patient reported outcome measure (PROM), has not been studied. The aim was to investigate how the most common problems on the ICF checklist were associated with shoulder function and disability.Materials and methods: In a cross-sectional design 164 patients ≥ 18 years with chronic shoulder pain were included. The ICF checklist, the Disability of the Arm, Shoulder, and Hand (DASH) outcome measure and the Self-Report Comorbidity Questionnaire were used. A hierarchical regression model tested categories for functioning on the ICF checklist associated with disability on the DASH.Results: Mean age was 46.5 years, 54% were women. 85% had had the shoulder pain longer than 6 months. Mean DASH score was 33.2 points (SD 17.1). Adjusted R2 was 0.67. Older age, being woman and having a lower education explained 22% of the variance on the DASH. The body functions bodily pain, mobility of joints and energy and drive function explained 30% of the variance, and the activities and participation problems lifting and carrying objects, washing oneself and recreation and leisure explained an additional 13%.Conclusions: The shoulder disability was multi-dimensional and comprised body functions and activities and participation. And 67% of the variance in the DASH score was explained.Implications for rehabilitationPersistent shoulder pain results in multi-dimensional disability calling for a broader assessment of function.A biopsychosocial approach to shoulder pain and disability is recommended.Functioning assessed on the ICF checklist can be applied in the assessment of chronic shoulder pain as it contributes to the understanding of self-reported disability on a region specific outcome measure.

Radiological glenohumeral osteoarthritis in long-term type 1 diabetes. Prevalence and reliability of three classification systems. The Dialong shoulder study.

OBJECTIVE: In the present study, we evaluate the intra- and interrater agreement of radiological glenohumeral OA using three different classification systems and estimate the prevalence of radiological and clinical glenohumeral OA in patients with type 1 diabetes mellitus (DM1), for over 45 years and controls (The Dialong study). MATERIALS AND METHODS: We included 102 patients with DM1 (49% women, mean age, 61.9 years) and 73 controls (57% women, mean age, 62.6 years). Anterior-posterior shoulder radiographs were interpreted by two observers applying the Kellgren-Lawrence (K-L), Samilson-Prieto (S-P) and Samilson-Prieto Allain (S-PA) classifications. RESULTS: The interrater agreement was moderate (weighted kappa, 0.46 to 0.48) for all classifications and the intrarater agreement mainly substantial (0.48-0.86) for both observers. The agreed prevalence of radiological OA was 26 and 18% (OR 1.6 (0.8 to 3.3), p = 0.22, 44 and 26% (OR 2.2 (1.2 to 4.2), p = 0.02) and 30 and 17% (OR 2.1 (1.0 to 4.5), p = 0.05) for the K-L, S-P and S-PA classifications respectively in the diabetes and control groups. The prevalence of moderate or severe radiological OA was 1 to 6% and clinical OA 1 to 2% with no difference between the groups. CONCLUSION: The prevalence of radiological glenohumeral OA was higher in the diabetes group with the Samilson-Prieto classification systems, but not associated with clinical OA. The interrater agreement was moderate. We recommend the Samilson-Prieto Allain classification for glenohumeral OA to avoid interpretation of osteophytes < 1 mm as OA in patient groups with a low pre-test likelihood of glenohumeral OA.

One year results of a randomized controlled trial on radial Extracorporeal Shock Wave Treatment, with predictors of pain, disability and return to work in patients with subacromial pain syndrome.

BACKGROUND: Radial Extracorporeal Shock Wave Therapy (rESWT) is increasingly used to treat patients with subacromial pain syndrome despite conflicting evidence of its effectiveness. Better knowledge regarding prognostic factors may contribute to the improvement in treatment and prognosis for the patients. AIM: The first aim of this study was to evaluate the effect of rESWT in addition to supervised exercises in patients with subacromial pain syndrome after one year. The second aim was to identify predictors of pain and disability and work status after one year in this patient group. DESIGN: A randomized, double-blind, sham-controlled trial. SETTING: An outpatient shoulder clinic of a University hospital. METHODS: Patients aged 25 to 70 years, with subacromial pain syndrome lasting at least three months were included and randomly assigned to receive either rESWT and supervised exercises or sham rESWT and supervised exercises. The Shoulder Pain and Disability Index (SPADI) and work status were assessed after one year. RESULTS: We screened 265 patients and enrolled 143; 74 were allocated to receive sham rESWT and exercises, and 69 were allocated to receive rESWT and exercises. After one year, no differences were found for the SPADI Score (mean difference -1.6, 95% confidence interval (CI) -10.2 to 7.0, P=0.71). Subgroup analysis of patients with calcification in the rotator cuff demonstrated no significant additional effect of rESWT to supervised exercises (mean difference -6.3, 95% CI -22.4 to 9.8, P=0.44). Marital status (single), frequent use of pain medication, not working at baseline, negative outcome expectations, low self-reported general health status and few supervised exercise sessions predicted a poor outcome on SPADI after one year. CONCLUSIONS: Radial ESWT was not superior to sham rESWT in addition to supervised exercises in the long term for patients with subacromial pain syndrome. The identified predictors for pain, disability and work should be assessed in future studies and addressed by clinicians in order to improve the effectiveness of supervised exercises. CLINICAL REHABILITATION IMPACT: Radial ESWT should not be recommended for patients with subacromial pain syndrome. Clinicians should assess patient`s outcome expectations, and if possible reduce the use of pain medication and sick leave in this patient group.

Risk factors for surgical site infections among 1,772 patients operated on for lumbar disc herniation: a multicentre observational registry-based study.

BACKGROUND: There are no previous studies evaluating risk factors for surgical site infections (SSIs) and the effectiveness of prophylactic antibiotic treatment (PAT), specifically for patients operated on for lumbar disc herniation. METHOD: This observational multicentre study comprises a cohort of 1,772 consecutive patients operated on for lumbar disc herniation without laminectomy or fusion at 23 different surgical units in Norway. The patients were interviewed about SSIs according to a standardised questionnaire at 3 months' follow-up. RESULTS: Three months after surgery, 2.3% of the patients had an SSI. Only no PAT (OR = 5.3, 95% CI = 2.2-12.7, p< 0.001) and longer duration of surgery than the mean time (68 min) (OR = 2.8, 95% CI = 1.2-6.6, p = 0.02) were identified as independent risk factors for SSI. Numbers needed to have PAT to avoid one SSI was 43. CONCLUSIONS: In summary, this study clearly lends support to the use of PAT in surgery for lumbar disc herniation. Senior surgeons assisting inexperienced colleagues to avoid prolonged duration of surgery could also reduce the occurrence of SSI.

Age and pro-inflammatory gene polymorphisms influence adjacent segment disc degeneration more than fusion does in patients treated for chronic low back pain.

PURPOSE: Does lumbar fusion lead to accelerated adjacent segment disc degeneration (ASDD) or is it explained by genetics and aging? The influence of genetics on ASDD remains to be explored. This study assesses whether the disc space height adjacent to a fused segment is associated with candidate gene single nucleotide polymorphisms (SNPs). METHODS: Patients with low back pain from four RCTs (N = 208 fusion; 77 non-operative treatment) underwent standing plain radiography and genetic analyses at 13 ± 4 years follow-up. Disc space height was measured using a validated computer-assisted distortion-compensated roentgen analysis technique and reported in standard deviations from normal values. Genetic association analyses included 34 SNPs in 25 structural, inflammatory, matrix degrading, apoptotic, vitamin D receptor and OA-related genes relevant to disc degeneration. These were analysed for their association with disc space height (after adjusting for age, gender, smoking, duration of follow-up and treatment group) first, separately, and then together in a stepwise multivariable model. RESULTS: Two SNPs from the IL18RAP gene (rs1420106 and rs917997) were each associated with a lower disc space height at the adjacent level (B = -0.34, p = 0.04 and B = -0.35, p = 0.04, respectively) and the MMP-9 gene SNP rs20544 was associated with a greater disc space height (B = 0.35, p = 0.04). Age (p < 0.001) and fusion (p < 0.008) were also significant variables in each analysis. The total explained variance in disc space height was for each SNP model 13-14 %, with 11-12 % of this being accounted for by the given SNP, 64-67 % by age and 19-22 % by fusion. In the multivariable regression analysis (with nine SNPs selected for entry, along with the covariates) the total explained variance in disc space height was 23 %, with the nine SNPs, age and fusion accounting for 45, 45 and 7 % of this, respectively. CONCLUSIONS: Age was the most significant determinant of adjacent segment disc space height followed by genetic factors, specifically inflammatory genes. Fusion explained a statistically significant but small proportion of the total variance. Much of the variance remained to be explained.

Catechol-O-methyltransferase (COMT) gene polymorphisms are associated with baseline disability but not long-term treatment outcome in patients with chronic low back pain.

PURPOSE: To examine the association between COMT and OPRM1 gene polymorphisms and pain and disability at baseline and long-term follow-up in patients treated for chronic low back pain (LBP). METHODS: 371 of 767 unrelated European patients recruited from four randomised trials underwent genetic analyses at mean 11.4 years follow-up. 274 patients had fusion and 97 had non-operative treatment. Association analyses included disability, pain, five single nucleotide polymorphisms (SNPs) in the COMT gene, and one SNP in the OPRM1 gene. Analyses were adjusted for age, gender, smoking, analgesics and treatment. RESULTS: Disability at baseline was significantly associated with COMT SNPs rs4818 (p = 0.02), rs6269 (p = 0.007), rs4633 (p = 0.04) rs2075507 (p = 0.009), two haplotypes (p < 0.002), age, gender and smoking (p ≤ 0.002). No significant associations with clinical variables were observed for OPRM1, or for COMT at long-term follow-up. CONCLUSIONS: Results suggest that genetic factors are partly responsible for the variation in disability levels in patients presenting with chronic LBP being considered for surgery; in contrast, genetics has no influence on the long-term outcome of treatment.

Patients' ratings of global perceived change during 2 years were strongly influenced by the current health status.

OBJECTIVES: To investigate the longitudinal validity of patients' ratings of global perceived change (GPC) and to assess the implications of using the GPC as the anchor to determine the minimal important change (MIC). STUDY DESIGN AND SETTING: Secondary analysis of data from a multicenter study including 380 patients with disc-related sciatica with follow-ups at 3, 6, 12, and 24 months. The GPC scale ranged from much worse to completely gone. Five patient-reported outcome measures were used. An MIC was defined as the mean change score in the actual outcome measure for patients reporting being better. The influence of patients' current state and baseline scores on the GPC was analyzed by multivariate linear regression. Differences in the magnitude of the MIC between the 3- and 24-month recall periods were analyzed by hierarchical linear models. RESULTS: Across all recall periods and outcome measures, the GPC was strongly influenced by the patient's state at the time of asking. In four of five outcome measures, the magnitude of the MIC increased when recall increased from 3 to 24 months. CONCLUSION: Caution is needed when using the GPC to determine the MIC of patient-reported outcome measures in patients with chronic conditions.

Prognostic factors for return to work in patients with sciatica.

BACKGROUND CONTEXT: Little is known about the prognostic factors for work-related outcomes of sciatica caused by disc herniation. PURPOSE: To identify the prognostic factors for return to work (RTW) during a 2-year follow-up among sciatica patients referred to secondary care. STUDY DESIGN/SETTING: Multicenter prospective cohort study including 466 patients. Administrative data from the National Sickness Benefit Register were accessed for 227 patients. PATIENT SAMPLE: Two samples were used. Sample A comprised patients who at the time of inclusion in the cohort reported being on partial sick leave or complete sick leave or were undergoing rehabilitation because of back pain/sciatica. Sample B comprised patients who, according to the sickness benefit register, at the time of inclusion received sickness benefits or rehabilitation allowances because of back pain/sciatica. OUTCOME MEASURES: In Sample A, the outcome was self-reported return to full-time work at the 2-year follow-up. In Sample B, the outcome was time to first sustained RTW, defined as the first period of more than 60 days without receiving benefits from the register. METHODS: Significant baseline predictors of self-reported RTW at 2 years (Analysis A) were identified by multivariate logistic regression. Significant predictors of time to sustained RTW (Analysis B) were identified by multivariate Cox proportional hazard modeling. Both analyses included adjustment for age and sex. To assess the effect of surgery on the probability of RTW, analyses similar to A and B were performed, including the variable surgery (yes/no). RESULTS: One-fourth of the patients were still out of work at the 2-year follow-up. In Sample A (n=237), younger age, better general health, lower baseline sciatica bothersomeness, less fear-avoidance work, and a negative straight-leg-raising test result were significantly associated with a higher probability of RTW at the 2-year follow-up. Surgery was not significantly associated with the outcome. In Sample B (n=125), history of sciatica, duration of the current sciatica episode more than 3 months, greater sciatica bothersomeness, fear-avoidance work, and back pain were significantly associated with a longer time to sustained RTW. Surgery was significantly negatively associated with time to sustained RTW both in univariate (hazard ratio [HR] 0.60; 95% confidence interval [CI] 0.39, 0.93; p=.02) and in multivariate (HR 0.49; 95% CI 0.31, 0.79; p=.003) analyses. CONCLUSIONS: The baseline factors associated with RTW identified in multivariate analysis were age, general health, history of sciatica, duration of the current episode, baseline sciatica bothersomeness, fear-avoidance work, back pain, and the straight-leg-raising test result. Surgical treatment was associated with slower RTW, but surgical patients were more severely affected than patients treated without surgery; so, this finding should be interpreted with caution.

Comparison of the SF6D, the EQ5D, and the oswestry disability index in patients with chronic low back pain and degenerative disc disease.

BACKGROUND: The need for cost effectiveness analyses in randomized controlled trials that compare treatment options is increasing. The selection of the optimal utility measure is important, and a central question is whether the two most commonly used indexes - the EuroQuol 5D (EQ5D) and the Short Form 6D (SF6D) - can be used interchangeably. The aim of the present study was to compare change scores of the EQ5D and SF6D utility indexes in terms of some important measurement properties. The psychometric properties of the two utility indexes were compared to a disease-specific instrument, the Oswestry Disability Index (ODI), in the setting of a randomized controlled trial for degenerative disc disease. METHODS: In a randomized controlled multicentre trial, 172 patients who had experienced low back pain for an average of 6 years were randomized to either treatment with an intensive back rehabilitation program or surgery to insert disc prostheses. Patients filled out the ODI, EQ5D, and SF-36 at baseline and two-year follow up. The utility indexes was compared with respect to measurement error, structural validity, criterion validity, responsiveness, and interpretability according to the COSMIN taxonomy. RESULTS: At follow up, 113 patients had change score values for all three instruments. The SF6D had better similarity with the disease-specific instrument (ODI) regarding sensitivity, specificity, and responsiveness. Measurement error was lower for the SF6D (0.056) compared to the EQ5D (0.155). The minimal important change score value was 0.031 for SF6D and 0.173 for EQ5D. The minimal detectable change score value at a 95% confidence level were 0.157 for SF6D and 0.429 for EQ5D, and the difference in mean change score values (SD) between them was 0.23 (0.29) and so exceeded the clinical significant change score value for both instruments. Analysis of psychometric properties indicated that the indexes are unidimensional when considered separately, but that they do not exactly measure the same underlying construct. CONCLUSIONS: This study indicates that the difference in important measurement properties between EQ5D and SF6D is too large to consider them interchangeable. Since the similarity with the "gold standard" (the disease-specific instrument) was quite different, this could indicate that the choice of index should be determined by the diagnosis.

Poor agreement found between self-report and a public registry on duration of sickness absence.

OBJECTIVE: To investigate the agreement between self-report and a public registry regarding the occurrence and duration of sickness absence (SA) in patients with sciatica. STUDY DESIGN AND SETTING: Observational 2-year longitudinal study including 227 patients. Self-report SA data were obtained by postal questionnaires covering recall periods of 3, 6, and 12 months and compared with data from the Norwegian National Sickness Benefit Register. RESULTS: The percent agreement on the occurrence of SA between self-report and registry was above 85% for all three recall periods. The patients overestimated the duration of their SA by 2.4 (95% confidence interval, 1.1-3.7) weeks for the 3-month recall period. The 95% limits of agreement were generally wide, varying from -12.5 to 17.3 weeks for the 3-month recall period to -38.8 to 37.2 weeks for the 12-month period. For the 3-, 6-, and 12-month recall periods, 48.1%, 29.8%, and 27.3% of the patients reported an SA duration that differed by ≤1 week from that recorded in the registry. CONCLUSION: Mainly because of low precision, the agreement on the duration of SA was poor for all three recall periods. The agreement between self-report and registry regarding the occurrence of SA was good.

No difference in long-term trunk muscle strength, cross-sectional area, and density in patients with chronic low back pain 7 to 11 years after lumbar fusion versus cognitive intervention and exercises.

BACKGROUND CONTEXT: Reduced muscle strength and density observed at 1 year after lumbar fusion may deteriorate more in the long term. PURPOSE: To compare the long-term effect of lumbar fusion and cognitive intervention and exercises on muscle strength, cross-sectional area, density, and self-rated function in patients with chronic low back pain (CLBP) and disc degeneration. STUDY DESIGN: Randomized controlled study with a follow-up examination at 8.5 years (range, 7-11 years). PATIENTS AND METHODS: Patients with CLBP and disc degeneration randomized to either instrumented posterolateral fusion of one or both of the two lower lumbar levels or a 3-week cognitive intervention and exercise program were included. Isokinetic muscle strength was measured by a Cybex 6000 (Cybex-Lumex, Inc., Ronkonkoma, NY, USA). All patients had previous experience with the test procedure. The back extension (E) flexion (F) muscles were tested, and the E/F ratios were calculated. Cross-sectional area and density of the back muscles were measured at the L3-L4 segment by computed tomography. Patients rated their function by the General Function Score. OUTCOME MEASURES: Trunk muscle strength, cross-sectional area, density, and self-rated function. RESULTS: Fifty-five patients (90%) were included at long-term follow-up. There were no significant differences in cross-sectional area, density, muscle strength, or self-rated function between the two groups. The cognitive intervention and exercise group increased trunk muscle extension significantly (p<.05), and both groups performed significantly better on trunk muscle flexion tests (p<.01) at long-term follow-up. On average, self-rated function improved by 56%, cross-sectional area was reduced by 8.5%, and muscle density was reduced by 27%. CONCLUSION: Although this study did not assess the morphology of muscles likely damaged by surgery, trunk muscle strength and cross-sectional area above the surgical levels are not different between those who had lumbar fusion or cognitive intervention and exercises at 7- to 11-year follow-up.

Protocol for the Cognitive Interventions and Nutritional Supplements (CINS) trial: a randomized controlled multicenter trial of a brief intervention (BI) versus a BI plus cognitive behavioral treatment (CBT) versus nutritional supplements for patients with long-lasting muscle and back pain.

BACKGROUND: Brief intervention programs are clinically beneficial, and cost efficient treatments for low back pain, when offered at 8-12 weeks, compared with treatment as usual. However, about 30% of the patients do not return to work. The European Guidelines for treatment of chronic low back pain recommends Cognitive Behavioral Therapy (CBT), but conclude that further research is needed to evaluate the effectiveness of CBT for chronic low back pain. METHODS/DESIGN: The aim of the multicenter CINS trial (Cognitive Interventions and Nutritional Supplements) is to compare the effectiveness of 4 different interventions; Brief Intervention, Brief Intervention and CBT, Brief Intervention and nutritional supplements of seal oil, and Brief Intervention and nutritional supplements of soy oil. All participants will be randomly assigned to the interventions. The nutritional supplements will be tested in a double blind design. 400 patients will be recruited from a population of chronic low back pain patients that have been sick listed for 2-10 months. Four outpatient clinics, located in different parts of Norway, will participate in recruitment and treatment of the patients.The Brief Intervention is a one session cognitive, clinical examination program based on a non-injury model, where return to normal activity and work is the main goal, and is followed by two booster sessions. The CBT is a tailored treatment involving 7 sessions, following a detailed manual. The nutritional supplements consist of a dosage of 10 grams of either soy or seal oil (capsules) per day for 3 months, administered in a double blind design. All patients will be followed up with questionnaires after 3, 6 and 12 months, while sick leave data will be collected up to at least 24 months after randomization. The primary outcome of the study is sick leave and will be based on register data from the National Insurance Administration. Secondary outcomes include self-reported data on disability, pain, and psychological variables. CONCLUSIONS: To our knowledge, the CINS trial will be the largest, randomized trial of psychological and nutritional interventions for chronic low back pain patients to date. It will provide important information regarding the effectiveness of CBT and seal oil for chronic low back pain patients. TRIAL REGISTRATION: http://www.clinicaltrials.gov, with registration number NCT00463970.

Comorbid subjective health complaints in patients with sciatica: a prospective study including comparison with the general population.

OBJECTIVE: Chronic nonspecific low back pain is accompanied by high rates of comorbid mental and physical conditions. The aims of this study were to investigate if patients with specific back pain, that is, sciatica caused by lumbar herniation, report higher rates of subjective health complaints (SHCs) than the general population and if there is an association between change in sciatica symptoms and change in SHCs over a 12-month period. METHODS: A multicenter cohort study of 466 sciatica patients was conducted with follow-up at 3 months and 1 year. Comorbid SHCs were measured by 27 items of the SHC inventory. Odds ratios (ORs) for each SHC were calculated with comparison to a general population sample (n=928) by logistic regression. The SHC number was calculated by summing all complaints present. RESULTS: At baseline, the ORs for reporting SHCs for the sciatica patients were significantly elevated in 15 of the 27 items with a mean (S.D.) SHC number of 7.5 (4.4), compared to 5.2 (4.4) in the general population (P<.01). Among those who during the 1-year follow-up period fully recovered from their sciatica, the SHC number was reduced to normal levels. Among those with persisting or worsening sciatica, the number increased to a level almost double that of the general population. CONCLUSION: Compared to the general population, the prevalence of subjective health complaints in sciatica is increased. During follow-up, the number of health complaints increased in patients with persisting or worsening sciatica.

Clinical, socio-demographic and radiological predictors of short-term outcome in rotator cuff disease.

BACKGROUND: Shoulder pain is common with rotator cuff disease as the most frequently used clinical diagnosis. There is a wide range of treatment options for this condition, but limited evidence to guide patients and clinicians in the choice of treatment strategy. The purpose of this study was to investigate possible prognostic factors of short-term outcome after corticosteroid injection for rotator cuff disease. METHODS: We performed analyses of data from 104 patients who had participated in a randomized controlled study. Socio-demographic, clinical and radiographic baseline factors were assessed for association with outcome at six-weeks follow-up evaluated by Shoulder Pain and Disability Index (SPADI) and patient perceived outcome. Factors with significant univariate association were entered into multivariate linear and logistic regression analyses. RESULTS: In the multivariate analyses; a high SPADI score indicating pain and disability at follow-up was associated with decreasing age, male gender, high baseline pain and disability, being on sick-leave, and using regular pain medication. A successful patient perceived outcome was associated with not being on sick-leave, high active abduction, local corticosteroid injection and previous cortisone injections. Structural findings of rotator cuff tendon pathology on MRI and bursal exudation or thickening on ultrasonography did not contribute to the predictive model. CONCLUSIONS: Baseline characteristics were associated with outcome after corticosteroid injection in rotator cuff disease. Sick-leave was the best predictor of poor short-term outcome. TRIAL REGISTRATION: Clinical trials NCT00640575.

Determinants of the shoulder pain and disability index in patients with subacromial shoulder pain.

OBJECTIVE: To examine the influence of determinants on the Shoulder Pain and Disability Index. DESIGN: A cross-sectional study. Baseline registrations were applied. PATIENTS: Two hundred patients with subacromial shoulder pain lasting at least 3 months. METHODS: A questionnaire consisting of possible determinants, 2 independent variables regarding pain and 2 regarding function, and the outcome measurement. Two multiple regression models (one with and one without the independent variables of pain and function) for the Shoulder Pain and Disability Index, the 2 subscales, and the determinants, were performed. RESULTS: The included determinants explained 29% of the variance of the Shoulder Pain and Disability Index (25% for pain and 33% for disability subscale) with pain medication, emotional distress, flexion, and the hand-behind-back range accounting for 26%. When pain and function were included, the final model explained 65% of the variance, with gender, education and range of flexion showing significance. CONCLUSION: The determinants explained 26% of the variance of the Shoulder Pain and Disability Index, but explained only a minor proportion when pain and function were included. This supports the Shoulder Pain and Disability Index as a shoulder pain and disability questionnaire.