Impact of spinal cord stimulation on sick leave and disability pension in patients with chronic neuropathic pain: a real-world evidence study in Sweden.

ABSTRACT: Current research indicates that spinal cord stimulation (SCS) has a positive short-term impact on outcomes, such as quality of life, pain, and productivity in patients with chronic neuropathic pain. However, there is a need for studies on larger population samples. This study used data from Swedish national registers to analyze change and predictors of sick leave and disability pension 2 years before and after SCS treatment. Patients with SCS implanted between 2006 and 2017, and a reference group consisting of 5 individuals matched to each SCS patient without replacement with respect to age, sex, and region of residence, were included. A difference-in-difference approach was used to compare the average change (2 years after treatment vs 2 years before treatment) in net disability days and indirect cost related to disability days for the SCS group, compared with the average change for the reference group. The results showed that SCS treatment in Sweden is associated with a decrease of 21 disability days and consequent decrease in indirect cost of €4127 in working age patients. Large work loss prior to index date was also demonstrated (average 214 days before 1 year), indicating a significant burden on the patient, employers, and the society at large. The number of disability days varied considerably depending on age, sex, socioeconomic variables, and comorbidities; however, the effect of SCS seemed to have little association with patient characteristics. This economic benefit needs to be considered, as well as the clinical outcome, when evaluating the full societal value of SCS.

Handling of missing items in the Oswestry disability index and the neck disability index. A study from Swespine, the National Swedish spine register.

PURPOSE: The Oswestry Disability Index (ODI) and the Neck Disability Index (NDI) scoring algorithms used by the Swedish spine register (Swespine) until April 2022 handled missing items somewhat differently than the original algorithms. The purpose of the current study was to evaluate possible differences in the ODI and NDI scores between the Swespine and the original scoring algorithms. METHODS: Patients surgically treated for degenerative conditions of the lumbar or cervical spine between 2003-2019 (lumbar) and 2006-2019 (cervical) were identified in Swespine. Preoperative and 1-year postoperative ODI/NDI data were used to evaluate differences between the Swespine and the original ODI/NDI algorithms with adjustment for at most 1 or 2 missing items using mean imputation. RESULTS: The preoperative as well as the 1-year postoperative ODI/NDI were approximately 1 unit out of 100 smaller for the Swespine algorithm, irrespective of adjustment model. The differences between preoperative and postoperative ODI/NDI scores were similar between the Swespine and the original scoring algorithms. There were occasional statistically significant differences between the preoperative-postoperative differences due to large sample sizes. CONCLUSIONS: The Swespine algorithms, used until April 2022, underestimated the ODI and NDI by approximately 1 out of 100 units compared with the original algorithms. In addition, there were no statistically significant differences between the original algorithms when adjusting for at most 1 or 2 missing items. The algorithm has now been changed, also for historical data.

Prediction of outcome after spinal surgery-using The Dialogue Support based on the Swedish national quality register.

PURPOSE: To evaluate the predictive precision of the Dialogue Support, a tool for additional help in shared decision-making before surgery of the degenerative spine. METHODS: Data in Swespine (Swedish national quality registry) of patients operated between 2007 and 2019 found the development of prediction algorithms based on logistic regression analyses, where socio-demographic and baseline variables were included. The algorithms were tested in four diagnostic groups: lumbar disc herniation, lumbar spinal stenosis, degenerative disc disease and cervical radiculopathy. By random selection, 80% of the study population was used for the prediction of outcome and then tested against the actual outcome of the remaining 20%. Outcome measures were global assessment of pain (GA), and satisfaction with outcome. RESULTS: Calibration plots demonstrated a high degree of concordance on a group level. On an individual level, ROC curves showed moderate predictive capacity with AUC (area under the curve) values 0.67-0.68 for global assessment and 0.6-0.67 for satisfaction. CONCLUSION: The Dialogue Support can serve as an aid to both patient and surgeon when discussing and deciding on surgical treatment of degenerative conditions in the lumbar and cervical spine. LEVEL OF EVIDENCE: I.

Does the order of total hip replacement and lumbar spinal stenosis surgery influence patient-reported outcomes: An observational register study.

Patients with degenerative hip and lumbar spine disorders requiring surgery in both locations is fairly common in clinical practice. We investigated if the order of total hip replacement (THR) and lumbar spinal stenosis surgery (LSSS) influences patient-reported outcomes (PROs). We used data from the Swedish Hip Arthroplasty Register (SHAR) and the Swedish Spine Register (Swespine), on patients operated with THR and LSSS in years 2002 to 2012. To increase the probability of having symptomatic disorders in both locations at the time of the first surgery, we only included patients with both LSSS and THR performed within 2 years. Linear and logistic regression analyses adjusted for age, sex, preoperative PROs, and time between surgeries were used to investigate the association between order of surgeries and the generic PRO measurements EQ-5D and EQ VAS. Eighty-four patients had THR prior to LSSS and 171 patients LSSS prior to THR. Linear regression showed that LSSS prior to THR was associated with higher EQ-5D index (B = 0.09, 95% confidence interval [CI] 0.03-0.16) and EQ VAS (B = 5.6, 95% CI 0.4-10.9) 1 year after the last surgery. Logistic regression showed that the odds ratio [OR] for not having any problems in the "pain" (OR = 3.0, 95% CI 1.5-6.3) and "anxiety/depression" (OR = 2.3, 95% CI 1.3-4.1) dimensions were higher for LSSS before THR. In our cohort, LSSS before THR was associated with better health-related quality of life outcomes compared to the reverse order. The results from our cohort can be helpful in a clinical situation where the physician gives advice to an individual patient when choosing the order of procedures. However, further studies are necessary in order to confirm these results in other cohorts. At present, standard of care remains that order of surgery should be individualized for each patient, with guidance from the operating surgeons.

[Antibiotics should not be used for treating back pain due to Modic changes].

Infection has been proposed as a cause of back pain in individuals with Modic changes. This review summarises the knowledge on this topic in Scandinavia. A Norwegian randomized controlled trial could not replicate results in favor of antibiotic treatment for such patients. A Danish study demonstrated that patients with low back pain and Modic changes had similar physical disability-scores and less sick leave due to back pain than individuals without Modic changes at long-term follow-up (>10 years). A Swedish study displayed equal bacterial presence in discs of patients operated for lumbar disc herniation and in control patients, indicating that the presence of bacteria is caused by contamination during the surgical procedure and is not related to back pain.

[Antibiotics should not be used to treat patients with back/leg pain]. / Antibiotika ska med dagens kunskap inte användas vid ryggvärk ­ med eller utan benvärk.

This report is based on results from three research groups in Sweden (Fritzell et al), Denmark (Udby et al), and Norway (Bråten et al). The groups have conducted studies published in international journals in 2019 [8-10]. The results complement each other and strongly suggest that antibiotics, in the absence of clear signs of a clinically relevant infection (discitis/spondylitis), should not be used for back pain with or without leg pain. The Swedish study showed that bacteria found in the disc/vertebra during surgery are very likely due to contamination [8], the Danish study showed that patients with Modic Changes (MC) on MR in the long term were not associated with more back pain or functional impairment than in patients without MC [9], and the Norwegian study showed that antibiotics for residual back pain after previous disc herniation had no better clinical effect than placebo [10]. Antibiotic resistance is one of the biggest threats to public health today and in the future.

Correction to: Bacteria: back pain, leg pain and Modic sign-a surgical multicenter comparative study.

Unfortunately, the 5th author name was incorrectly published in the original paper. The complete correct name is given below.

Cost and Health Outcomes Patterns in Patients Treated With Spinal Cord Stimulation Following Spine Surgery-A Register-Based Study.

OBJECTIVE: Spinal cord stimulation (SCS), a minimally invasive treatment option for long-term neuropathic pain, has been shown to be effective in patients with persisting neuropathic pain after spine surgery. However, little is known about the long-term cost and quality-of-life (QoL) patterns in SCS-treated patients. The aim is to describe the use of SCS, costs, pre-spine-surgery and post-spine-surgery QoL, and reported pain intensity, in patients who have undergone spine surgery and subsequent SCS implantation. The results will be related to outcome and cost in spine surgery patients in general. MATERIALS AND METHODS: A research database comprised from six Swedish national and regional registers, and the spine surgery quality-of-care register Swespine was utilized. Two cohorts were identified: all patients who had spine surgery (N = 73,765) and patients who had spine surgery and subsequent SCS implantation (N = 239). Costs were analyzed before and after spine surgery for both cohorts, as well as before and after SCS implantation for the second cohort. QoL was explored by estimating patient-reported outcome measures such as pain intensity, Oswestry Disability Index, and EuroQol-5Dimensions from spine surgery up to five years post-spine surgery. RESULTS: In spine surgery patients, mean QoL and pain intensity levels improved following surgery. Patients subsequently treated with SCS had lower reported QoL and higher costs before the initial spine surgery, and spine surgery did not lead to any substantial improvements, however, costs decreased following SCS implantation in these patients.

Surgical Treatment of Degenerative Disk Disease in Three Scandinavian Countries: An International Register Study Based on Three Merged National Spine Registers.

STUDY DESIGN: Observational study of prospectively collected data. OBJECTIVES: Patients with chronic low back pain resistant to nonoperative treatment often face a poor prognosis for recovery. The aim of the current study was to compare the variation and outcome of surgical treatment of degenerative disc disease in the Scandinavian countries based on The International Consortium for Health Outcomes Measurement core spine data sets. METHODS: Anonymized individual level data from 3 national registers were pooled into 1 database. At the time of surgery, the patient reports data on demographics, lifestyle topics, comorbidity, and data on health-related quality of life such as Oswestry Disability Index, Euro-Qol-5D, and back and leg pain scores. The surgeon records diagnosis, type of surgery performed, and complications. One-year follow-ups are obtained with questionnaires. Baseline and 1-year follow-up data were analyzed to expose any differences between the countries. RESULTS: A total of 1893 patients were included. At 1-year follow-up, 1315 (72%) patients responded. There were statistically significant baseline differences in age, smoking, comorbidity, frequency of previous surgery and intensity of back and leg pain. Isolated fusion was the primary procedure in all the countries ranging from 84% in Denmark to 76% in Sweden. There was clinically relevant improvement in all outcome measures except leg pain. CONCLUSIONS: In homogenous populations with similar health care systems the treatment traditions can vary considerably. Despite variations in preoperative variables, patient reported outcomes improve significantly and clinically relevant with surgical treatment.

Bacteria: back pain, leg pain and Modic sign-a surgical multicentre comparative study.

PURPOSE: To compare bacterial findings in pain-generating degenerated discs in adults operated on for lumbar disc herniation (LDH), and mostly also suffering from low back pain (LBP), with findings in adolescent patients with non-degenerated non-pain-generating discs operated on for scoliosis, and to evaluate associations with Modic signs on magnetic resonance imaging (MRI). Cutibacterium acnes (Propionibacterium acnes) has been found in painful degenerated discs, why it has been suggested treating patients with LDH/LBP with antibiotics. As multidrug-resistant bacteria are a worldwide concern, new indications for using antibiotics should be based on solid scientific evidence. METHODS: Between 2015 and 2017, 40 adults with LDH/LBP (median age 43, IQR 33-49) and 20 control patients with scoliosis (median age 17, IQR 15-20) underwent surgery at seven Swedish hospitals. Samples were cultured from skin, surgical wound, discs and vertebrae. Genetic relatedness of C. acnes isolates was investigated using single-nucleotide polymorphism analysis. DNA samples collected from discs/vertebrae were analysed using 16S rRNA-based PCR sequencing. MRI findings were assessed for Modic changes. RESULTS: No bacterial growth was found in 6/40 (15%) LDH patients, compared with 3/20 (15%) scoliosis patients. Most positive samples in both groups were isolated from the skin and then from subcutis or deep within the wound. Of the four disc and vertebral samples from each of the 60 patients, 235/240 (98%) were DNA negative by bacterial PCR. A single species, C. acnes, was found exclusively in the disc/vertebra from one patient in each group. In the LDH group, 29/40 (72%) patients had at least one sample with growth of C. acnes, compared to 14/20 (70%) in the scoliosis group. Bacterial findings and Modic changes were not associated. CONCLUSIONS: Cutibacterium acnes found in discs and vertebrae during surgery for disc herniation in adults with degenerated discs may be caused by contamination, as findings in this group were similar to findings in a control group of young patients with scoliosis and non-degenerated discs. Furthermore, such findings were almost always combined with bacterial findings on the skin and/or in the wound. There was no association between preoperative Modic changes and bacterial findings. Antibiotic treatment of lumbar disc herniation with sciatica and/or low back pain, without signs of clinical discitis/spondylitis, should be seriously questioned. These slides can be retrieved under Electronic Supplementary Material.

The Association Between Patient Reported Outcomes of Spinal Surgery and Societal Costs: A Register Based Study.

STUDY DESIGN: Retrospective register-based study using Swedish registers and data prospectively collected in quality register Swespine. OBJECTIVE: Analyze the association of societal costs and spine surgery outcome in low back pain (LBP) patients based on patient reported outcome measures (PROMs). SUMMARY OF BACKGROUND DATA: Studies show that LBP has a substantial impact on societal cost. There are indications that the burden diverges over different patient groups, but little is known about cost patterns in relation to PROMs of LBP surgery. METHODS: We utilized a database with data from six registers. All lumbar spine surgery patients registered in Swespine 2000 to 2012 were identified. Swespine collects PROMs Global Assessment of pain improvement (GA), Oswestry Disability Index (ODI), Visual Analog Scale (VAS), and EuroQol five-dimension scale (EQ-5D). A literature search was conducted to identify threshold changes in ODI, VAS, and EQ-5D representing a significant improvement or deterioration as defined by the minimal clinically important difference (MCID). We categorized patients into groups by their GA response at 2-year follow-up and estimated mean changes in ODI, VAS, and EQ-5D for each group. These changes were compared with the MCID thresholds to determine a GA-anchored classification of surgical outcomes. Costs consisted of out/inpatient care, sick leave, early retirement, and pharmaceuticals. RESULTS: In total, 12,350 patients were included. GA 1-2 ("pain has disappeared"/"pain is much improved") were labeled successful surgery outcomes (67%), GA 3 ("pain somewhat improved"), undetermined (16%), and GA 4-5 ("no change in pain"/"pain has worsened") unsuccessful (17%). Costs of the unsuccessful and undetermined were higher than of the successful during the entire study period, with differences increasing markedly post-surgery. For the successful, a downward cost trend was observed; costs almost returned to the level observed 3 years pre-surgery. No such trend was observed in the other groups. CONCLUSION: Identifying patients with higher probability of responding to surgery could lead to improved health and substantial societal cost savings. LEVEL OF EVIDENCE: 3.

Lumbar spinal stenosis: comparison of surgical practice variation and clinical outcome in three national spine registries.

BACKGROUND CONTEXT: Decompression surgery for lumbar spinal stenosis (LSS) is the most common spinal procedure in the elderly. To avoid persisting low back pain, adding arthrodesis has been recommended, especially if there is a coexisting degenerative spondylolisthesis. However, this strategy remains controversial, resulting in practice-based variation. PURPOSE: The present study aimed to evaluate in a pragmatic study if surgical selection criteria and variation in use of arthrodesis in three Scandinavian countries can be linked to variation in treatment effectiveness. STUDY DESIGN: This is an observational study based on a combined cohort from the national spine registries of Norway, Sweden, and Denmark. PATIENT SAMPLE: Patients aged 50 and older operated during 2011-2013 for LSS were included. OUTCOME MEASURES: Patient-Reported Outcome Measures (PROMs): Oswestry Disability Index (ODI) (primary outcome), Numeric Rating Scale (NRS) for leg pain and back pain, and health-related quality of life (Euro-Qol-5D) were reported. Analysis included case-mix adjustment. In addition, we report differences in hospital stay. METHODS: Analyses of baseline data were done by analysis of variance (ANOVA), chi-square, or logistic regression tests. The comparisons of the mean changes of PROMs at 1-year follow-up between the countries were done by ANOVA (crude) and analysis of covariance (case-mix adjustment). RESULTS: Out of 14,223 included patients, 10,890 (77%) responded at 1-year follow-up. Apart from fewer smokers in Sweden and higher comorbidity rate in Norway, baseline characteristics were similar. The rate of additional fusion surgery (patients without or with spondylolisthesis) was 11% (4%, 47%) in Norway, 21% (9%, 56%) in Sweden, and 28% (15%, 88%) in Denmark. At 1-year follow-up, the mean improvement for ODI (95% confidence interval) was 18 (17-18) in Norway, 17 (17-18) in Sweden, and 18 (17-19) in Denmark. Patients operated with arthrodesis had prolonged hospital stay. CONCLUSIONS: Real-life data from three national spine registers showed similar indications for decompression surgery but significant differences in the use of concomitant arthrodesis in Scandinavia. Additional arthrodesis was not associated with better treatment effectiveness.

Predicting clinical outcome and length of sick leave after surgery for lumbar spinal stenosis in Sweden: a multi-register evaluation.

PURPOSE: Lumbar spinal stenosis (LSS) can be surgically treated, with variable outcome. Studies have linked socioeconomic factors to outcome, but no nation-wide studies have been performed. This register-based study, including all patients surgically treated for LSS during 2008-2012 in Sweden, aimed to determine predictive factors for the outcome of surgery. METHODS: Clinical and socioeconomic factors with impact on outcome in LSS surgery were identified in several high-coverage registers, e.g., the national quality registry for spine surgery (Swespine, FU-rate 70-90%). Multivariate regression analyses were conducted to assess their effect on outcome. Two patient-reported outcome measures, Global Assessment of leg pain (GA) and the Oswestry Disability Index (ODI), as well as length of sick leave after surgery were analyzed. RESULTS: Clinical and socioeconomic factors significantly affected health outcome (both GA and ODI). Some predictors of a good outcome (ODI) were: being born in the EU, reporting no back pain at baseline, a high disposable income and a high educational level. Some factors predicting a worse outcome were previous surgery, having had back pain more than 2 years, having comorbidities, being a smoker, being on social welfare and being unemployed. CONCLUSIONS: The study highlights the relevance of adding socioeconomic factors to clinical factors for analysis of patient-reported outcomes, although the causal pathway of most predictors' impact is unknown. These findings should be further investigated in the perspective of treatment selection for individual LSS patients. The study also presents a foundation of case mix algorithms for predicting outcome of surgery for LSS. These slides can be retrieved under Electronic Supplementary Material.

Effectiveness of surgery for sciatica with disc herniation is not substantially affected by differences in surgical incidences among three countries: results from the Danish, Swedish and Norwegian spine registries.

PURPOSE: Yearly incidence of surgery for symptomatic lumbar disc herniation varies and is 29/100,000 in Sweden, 46/100,000 in Denmark and 58/100,000 in Norway. This variation was used to study whether differences in surgical incidence were associated with differences in preoperative patient characteristics as well as patient-reported outcomes. METHODS: Data from the national spine registers in Sweden, Denmark and Norway during 2011-2013 were pooled, and 9965 individuals, aged 18-65 years, of which 6468 had one-year follow-up data, were included in the study. Both absolute and case-mix-adjusted comparisons of the primary outcome Oswestry Disability Index (ODI) and the secondary outcomes EQ-5D-3L, and Numerical Rating Scale (NRS) for leg and back pain were performed. Case-mix adjustment was done for baseline age, sex, BMI, smoking, co-morbidity, duration of leg pain and preoperative value of the dependent variable. RESULTS: Mean improvement in the outcome variables exceeded previously described minimal clinical important change in all countries. Mean (95% CI) final scores of ODI were 18 (17-18), 19 (18-20) and 15 (15-16) in Sweden, Denmark and Norway, respectively. Corresponding results of EQ-5D-3L were 0.74 (0.73-0.75), 0.73 (0.72-0.75) and 0.75 (0.74-0.76). Results of NRS leg and back pain behaved similarly. Case-mix adjustment did not alter the findings substantially. CONCLUSION: We found no clear association between incidence of surgery for lumbar disc herniation and preoperative patient characteristics as well as outcome, and the differences between the countries were lower than the minimal clinical important difference in all outcomes. These slides can be retrieved under Electronic Supplementary Material.

Cost of low back pain: results from a national register study in Sweden.

PURPOSE: To estimate the societal costs of low back pain with/without radiating leg pain (LBP). LBP is a major burden in terms of both personal suffering and societal costs. METHODS: Patients visiting healthcare providers with a LBP-diagnosis in the Western region of Sweden (Västra Götaland) in 2008-2011 were identified in national registers and an administrative patient database. Direct healthcare costs and indirect costs in terms of sick leave and early retirement were summarized over time periods called LBP episodes, starting with a LBP-related healthcare contact or work absence due to LBP and ended when 6 months had elapsed without any LBP-related healthcare contact or work absence. RESULTS: The mean total cost per episode was estimated at €2753 with a mean duration of 51 days. There was a sharp increase in total cost the first month after the LBP episode started and a marked decrease from the second month. Total cost leveled off at a higher level during the 2 years after episode start compared with the 2 years before episode start. The total economic burden of LBP in Sweden including all LBP episodes that started in 2011 was estimated at €740 million, or €78 per capita. CONCLUSIONS: LBP has an apparent impact on the overall resource use and work loss. The results indicate that there is a high short-term cost increase at the beginning of an LBP episode, but also that the costs decrease in the long term after the LBP symptoms have come to clinical attention. These slides can be retrieved under Electronic Supplementary Material.