Surgery with disc prosthesis versus rehabilitation in patients with low back pain and degenerative disc: two year follow-up of randomised study

Objective To compare the efficacy of surgery with disc prosthesis versus non-surgical treatment for patients with chronic low back pain

Is the presence of foraminal stenosis associated with outcome in lumbar spinal stenosis patients treated with posterior microsurgical decompression

Background We aim to investigate associations between preoperative radiological findings of lumbar foraminal stenosis with clinical outcomes after posterior microsurgical decompression in patients with predominantly central lumbar spinal stenosis (LSS). Methods The study was an additional analysis in the NORDSTEN Spinal Stenosis Trial. In total, 230 men and 207 women (mean age 66.8 (SD 8.3)) were included. All patients underwent an MRI including T1- and T2-weighted sequences. Grade of foraminal stenosis was dichotomized into none to moderate (0–1) and severe (2–3) category using Lee’s classification system. The Oswestry Disability Index (ODI), Zurich Claudication Questionnaire (ZCQ), and numeric rating scale (NRS) for back and leg pain were collected at baseline and at 2-year follow-up. Primary outcome was a reduction of 30% or more on the ODI score. Secondary outcomes included the mean improvement on the ODI, ZCQ, and NRS scores. We performed multivariable regression analyses with the radiological variates foraminal stenosis, Pfirrmann grade, Schizas score, dural sac cross-sectional area, and the possible plausible confounders: patients’ gender, age, smoking status, and BMI. Results The cohort of 437 patients presented a high degree of degenerative changes at baseline. Of 414 patients with adequate imaging of potential foraminal stenosis, 402 were labeled in the none to moderate category and 12 in the severe category. Of the patients with none to moderate foraminal stenosis, 71% achieved at least 30% improvement in ODI. Among the patients with severe foraminal stenosis, 36% achieved at least 30% improvement in ODI. A significant association between severe foraminal stenosis and less chance of reaching the target of 30% improvement in the ODI score after surgery was detected: OR 0.22 (95% CI 0.06, 0.83), p=0.03. When investigating outcome as continuous variables, a similar association between severe foraminal stenosis and less improved ODI with a mean difference of 9.28 points (95%CI 0.47, 18.09; p=0.04) was found. Significant association between severe foraminal stenosis and less improved NRS pain in the lumbar region was also detected with a mean difference of 1.89 (95% CI 0.30, 3.49; p=0.02). No significant association was suggested between severe foraminal stenosis and ZCQ or NRS leg pain. Conclusion In patients operated with posterior microsurgical decompression for LSS, a preoperative severe lumbar foraminal stenosis was associated with higher proportion of patients with less than 30% improvement in ODI.publishedVersio

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

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 mm2 (SD: 21.1). Postoperatively the area increased to a mean area of 120.6 mm2 (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. <p<Conclusion - Less aggressive decompression performed similarly to wider decompression across multiple different patient-reported outcome measures at two years following surgery

Surgery in Degenerative Spondylolisthesis: Does fusion improve outcome in subgroups? A secondary analysis from a randomized trial (NORDSTEN trial)

BACKGROUND CONTEXT Patients with spinal stenosis and degenerative spondylolisthesis are treated surgically with decompression alone or decompression with fusion. However, there is debate regarding which subgroups of patients may benefit from additional fusion. PURPOSE To investigate possible treatment effect modifiers and prognostic variables among patients operated for spinal stenosis and degenerative spondylolisthesis. DESIGN A secondary exploratory study using data from the Norwegian Degenerative Spondylolisthesis and Spinal Stenosis (NORDSTEN-DS) trial. Patients were randomized to decompression alone or decompression with instrumented fusion. PATIENT SAMPLE The sample in this study consists of 267 patients from a randomized multicenter trial involving 16 hospitals in Norway. Patients were enrolled from February 12, 2014, to December 18, 2017. The study did not include patients with degenerative scoliosis, severe foraminal stenosis, multilevel spondylolisthesis, or previous surgery. OUTCOME MEASURES The primary outcome was an improvement of ≥ 30% on the Oswestry Disability Index score (ODI) from baseline to 2-year follow-up. METHODS When investigating possible variables that could modify the treatment effect, we analyzed the treatment arms separately. When testing for prognostic factors we analyzed the whole cohort (both treatment groups). We used univariate and multiple regression analyses. The selection of variables was done a priori, according to the published trial protocol. RESULTS Of the 267 patients included in the trial (183 female [67%]; mean [SD] age, 66 [7.6] years), complete baseline data for the variables required for the present analysis were available for 205 of the 267 individuals. We did not find any clinical or radiological variables at baseline that modified the treatment effect. Thus, none of the commonly used criteria for selecting patients for fusion surgery influenced the chosen primary outcome in the two treatment arms. For the whole cohort, less comorbidity (American Society of Anesthesiologists Classification [ASA], OR = 4.35; 95% confidence interval (CI [1.16–16.67]) and more preoperative leg pain (OR = 1.23; CI [1.02–1.50]) were significantly associated with an improved primary outcome. CONCLUSIONS In this study on patients with degenerative spondylolisthesis, neither previously defined instability criteria nor other pre-specified baseline variables were associated with better clinical outcome if fusion surgery was performed. None of the analyzed variables can be applied to guide the decision for fusion surgery in patients with degenerative spondylolisthesis. For both treatment groups, less comorbidity and more leg pain were associated with improved outcome 2 years after surgery.publishedVersio

Clinical and MRI findings in lumbar spinal stenosis: baseline data from the NORDSTEN study

Purpose The aim was to describe magnetic resonance imaging findings in patients planned for lumbar spinal stenosis surgery. Further, to describe possible associations between MRI findings and patient characteristics with patient reported disability or pain. Methods The NORDSTEN spinal stenosis trial included 437 patients planned for surgical decompression of LSS. The following MRI findings were evaluated before surgery: morphological (Schizas) and quantitative (cross-sectional area) grade of stenosis, disk degeneration (Pfirrmann), facet joint tropism and fatty infiltration of the multifidus muscle. Patients were dichotomized into a moderate or severe category for each radiological parameter classification. A multivariable linear regression analysis was performed to investigate the association between MRI findings and preoperative scores for Oswestry Disability Index, Zurich Claudication Questionnaire and Numeric rating scale for back and leg pain. The following patient characteristics were included in the analysis: gender, age, smoking and weight. Results The percentage of patients with severe scores was as follows: Schizas (C + D) 71.3%, cross-sectional area (< 75 mm2) 86.8%, Pfirrmann (4 + 5) 58.1%, tropism (≥ 15°) 11.9%, degeneration of multifidus muscle (2–4) 83.7%. Regression coefficients indicated minimal changes in severity of symptoms when comparing the groups with moderate and severe MRI findings. Only gender had a significant and clinically relevant association with ODI score. Conclusion In this cross-sectional study, the majority of the patients had MRI findings classified as severe LSS changes, but the findings had no clinically relevant association with patient reported disability and pain at baseline. Patient characteristics have a larger impact on disability and pain than radiological findings.publishedVersio

Comparable Increases in Dural Sac Area After Three Different Posterior Decompression Techniques for Lumbar Spinal Stenosis: Radiological Results From a Randomized Controlled Trial in the NORDSTEN Study

Purpose: To investigate changes in dural sac area after three different posterior decompression techniques in patients undergoing surgery for lumbar spinal stenosis. Decompression of the nerve roots is the main surgical treatment for lumbar spinal stenosis. The aim of this study was to radiologically investigate three commonly used posterior decompression techniques. Methods: The present study reports data from one of two multicenter randomized trials included in the NORDSTEN study. In the present trial, involving 437 patients undergoing surgery, we report radiological results after three different midline retaining posterior decompression techniques: unilateral laminotomy with crossover (UL) (n = 146), bilateral laminotomy (BL) (n = 142) and spinous process osteotomy (SPO) (n = 149). MRI was performed before and three months after surgery. The increase in dural sac area and Schizas grade at the most stenotic level was evaluated. Three different predefined surgical indicators of substantial decompression were used: (1) postoperative dural sac area of > 100 mm2, (2) increase in the dural sac area of at least 50% and (3) postoperative Schizas grade A or B. Results: No differences between the three surgical groups were found in the mean increase in dural sac area. Mean values were 66.0 (SD 41.5) mm2 in the UL-group, 71.9 (SD 37.1) mm2 in the BL-group and 68.1 (SD 41.0) mm2 in the SPO-group (p = 0.49). No differences in the three predefined surgical outcomes between the three groups were found. Conclusion: For patients with lumbar spinal stenosis, the three different surgical techniques provided the same increase in dural sac area.publishedVersio

Clinical outcome after surgery for lumbar spinal stenosis in patients with insignificant lower extremity pain. A prospective cohort study from the Norwegian registry for spine surgery

Background Spinal stenosis is a clinical diagnosis in which the main symptom is pain radiating to the lower extremities, or neurogenic claudication. Radiological spinal stenosis is commonly observed in the population and it is debated whether patients with no lower extremity pain should be labelled as having spinal stenosis. However, these patients is found in the Norwegian Registry for Spine Surgery, the main object of the present study was to compare the clinical outcomes after decompressive surgery in patients with insignificant lower extremity pain, with those with more severe pain. Methods This study is based on data from the Norwegian Registry for Spine Surgery (NORspine). Patients who had decompressive surgery in the period from 7/1–2007 to 11/3–2013 at 31 hospitals were included. The patients was divided into four groups based on preoperative Numeric Rating Scale (NRS)-score for lower extremity pain. Patients in group 1 had insignificant pain, group 2 had mild or moderate pain, group 3 severe pain and group 4 extremely severe pain. The primary outcome was change in the Oswestry Disability Index (ODI). Successfully treated patients were defined as patients reporting at least 30% reduction of baseline ODI, and the number of successfully treated patients in each group were recorded. Results In total, 3181 patients were eligible; 154 patients in group 1; 753 in group 2; 1766 in group 3; and 528 in group 4. Group 1 had significantly less improvement from baseline in all the clinical scores 12 months after surgery compared to the other groups. However, with a mean reduction of 8 ODI points and 56% of patients showing a reduction of at least 30% in their ODI score, the proportion of patients defined as successfully treated in group 1, was not significantly different from that of other groups. Conclusion This national register study shows that patients with insignificant lower extremity pain had less improvement in primary and secondary outcome parameters from baseline to follow-up compared to patients with more severe lower extremity pain

Decompression alone versusdecompression with instrumental fusionthe NORDSTEN degenerativespondylolisthesis trial (NORDSTEN-DS); study protocol for a randomized controlled trial

Background: Fusion in addition to decompression has become the standard treatment for lumbar spinal stenosis with degenerative spondylolisthesis (DS). The evidence for performing fusion among these patients is conflicting and there is a need for further investigation through studies of high quality. The present protocol describes an ongoing study with the primary aim of comparing the outcome between decompression alone and decompression with instrumented fusion. The secondary aim is to investigate whether predictors can be used to choose the best treatment for an individual. The trial, named the NORDSTEN-DS trial, is one of three studies in the Norwegian Degenerative Spinal Stenosis (NORDSTEN) study. Methods: The NORDSTEN-DS trial is a block-randomized, controlled, multicenter, non-inferiority study with two parallel groups. The surgeons at the 15 participating hospitals decide whether a patient is eligible or not according to the inclusion and exclusion criteria. Participating patients are randomized to either a midline preserving decompression or a decompression followed by an instrumental fusion. Primary endpoint is the percentage of patients with an improvement in Oswestry Disability Index version 2.0 of more than 30% from baseline to 2-year follow-up. Secondary outcome measurements are the Zürich Claudication Questionnaire, Numeric Rating Scale for back and leg pain, Euroqol 5 dimensions questionnaire, Global perceived effect scale, complications and several radiological parameters. Analysis and interpretation of results will also be conducted after 5 and 10years. Conclusion: The NORDSTEN/DS trial has the potential to provide Level 1 evidence of whether decompression alone should be advocated as the preferred method or not. Further on the study will investigate whether predictors exist and if they can be used to make the appropriate choice for surgical treatment for this patient group. Trial registration: ClinicalTrials.gov Identifier: NCT02051374. First Posted: January 31, 2014. Last Update Posted: February 14, 2018

Decompression alone versus decompression with instrumental fusion the NORDSTEN degenerative spondylolisthesis trial (NORDSTEN-DS); study protocol for a randomized controlled trial

Abstract Background Fusion in addition to decompression has become the standard treatment for lumbar spinal stenosis with degenerative spondylolisthesis (DS). The evidence for performing fusion among these patients is conflicting and there is a need for further investigation through studies of high quality. The present protocol describes an ongoing study with the primary aim of comparing the outcome between decompression alone and decompression with instrumented fusion. The secondary aim is to investigate whether predictors can be used to choose the best treatment for an individual. The trial, named the NORDSTEN-DS trial, is one of three studies in the Norwegian Degenerative Spinal Stenosis (NORDSTEN) study. Methods The NORDSTEN-DS trial is a block-randomized, controlled, multicenter, non-inferiority study with two parallel groups. The surgeons at the 15 participating hospitals decide whether a patient is eligible or not according to the inclusion and exclusion criteria. Participating patients are randomized to either a midline preserving decompression or a decompression followed by an instrumental fusion. Primary endpoint is the percentage of patients with an improvement in Oswestry Disability Index version 2.0 of more than 30% from baseline to 2-year follow-up. Secondary outcome measurements are the Zürich Claudication Questionnaire, Numeric Rating Scale for back and leg pain, Euroqol 5 dimensions questionnaire, Global perceived effect scale, complications and several radiological parameters. Analysis and interpretation of results will also be conducted after 5 and 10 years. Conclusion The NORDSTEN/DS trial has the potential to provide Level 1 evidence of whether decompression alone should be advocated as the preferred method or not. Further on the study will investigate whether predictors exist and if they can be used to make the appropriate choice for surgical treatment for this patient group. Trial registration ClinicalTrials.gov Identifier: NCT02051374. First Posted: January 31, 2014. Last Update Posted: February 14, 2018

Clinical outcome after surgery for lumbarspinal stenosis in patients with insignificantlower extremity pain. A prospective cohortstudy from the Norwegian registry for spine surgery

Background: Spinal stenosis is a clinical diagnosis in which the main symptom is pain radiating to the lower extremities, or neurogenic claudication. Radiological spinal stenosis is commonly observed in the population and it is debated whether patients with no lower extremity pain should be labelled as having spinal stenosis. However, these patients is found in the Norwegian Registry for Spine Surgery, the main object of the present study was to compare the clinical outcomes after decompressive surgery in patients with insignificant lower extremity pain, with those with more severe pain. Methods: This study is based on data from the Norwegian Registry for Spine Surgery (NORspine). Patients who had decompressive surgery in the period from 7/1–2007 to 11/3–2013 at 31 hospitals were included. The patients was divided into four groups based on preoperative Numeric Rating Scale (NRS)-score for lower extremity pain. Patients in group 1 had insignificant pain, group 2 had mild or moderate pain, group 3 severe pain and group 4 extremely severe pain. The primary outcome was change in the Oswestry Disability Index (ODI). Successfully treated patients were defined as patients reporting at least 30% reduction of baseline ODI, and the number of successfully treated patients in each group were recorded. Results: In total, 3181 patients were eligible; 154 patients in group 1; 753 in group 2; 1766 in group 3; and 528 in group 4. Group 1 had significantly less improvement from baseline in all the clinical scores 12months after surgery compared to the other groups. However, with a mean reduction of 8 ODI points and 56% of patients showing a reduction of at least 30% in their ODI score, the proportion of patients defined as successfully treated in group 1, was not significantly different from that of other groups. Conclusion: This national register study shows that patients with insignificant lower extremity pain had less improvement in primary and secondary outcome parameters from baseline to follow-up compared to patients with more severe lower extremity pain