Surgical interventions for degenerative lumbar spinal stenosis: a systematic review with network meta-analysis.

BACKGROUND: Several surgical options for degenerative lumbar spinal stenosis (LSS) are available, but current guidelines do not recommend which one should be prioritized. Although previous network meta-analyses (NMAs) have been performed on this topic, they have major methodological problems and could not provide the convincing evidence and clinical practical information required. METHODS: Randomized controlled trials (RCTs) comparing at least two surgical interventions were included by searching AMED, CINAHL, EMBASE, the Cochrane Library, and MEDLINE (inception to August 2023). A frequentist random-effects NMA was performed for physical function and adverse events due to any reason. For physical function, three follow-up time points were included: short-term (< 6 months post-intervention), mid-term (≥ 6 months but < 12 months), and long-term (≥ 12 months). Laminectomy was the reference comparison intervention. RESULTS: A total of 43 RCTs involving 5017 participants were included in the systematic review and 28 RCTs encompassing 14 types of surgical interventions were included in the NMA. For improving physical function (scale 0-100), endoscopic-assisted laminotomy (mean difference: - 8.61, 95% confidence interval: - 10.52 to - 6.69; moderate-quality evidence), laminectomy combined with Coflex (- 8.41, - 13.21 to - 3.61; moderate quality evidence), and X-stop (- 6.65, - 8.60 to - 4.71; low-quality evidence) had small effects at short-term follow-up; no statistical difference was observed at mid-term follow-up (very low- to low-quality evidence); at long-term follow-up, endoscopic-assisted laminotomy (- 7.02, - 12.95 to - 1.08; very low-quality evidence) and X-stop (- 10.04, - 18.16 to - 1.93; very low-quality evidence) had a small and moderate effect, respectively. Compared with laminectomy, endoscopic-assisted laminotomy was associated with fewer adverse events due to any reason (odds ratio: 0.27, 0.09 to 0.86; low-quality evidence). CONCLUSIONS: For adults with degenerative LSS, endoscopic-assisted laminotomy may be the safest and most effective intervention in improving physical function. However, the available data were insufficient to indicate whether the effect was sustainable after 6 months. TRIAL REGISTRATION: PROSPERO (CRD42018094180).

External validation of the deep learning system "SpineNet" for grading radiological features of degeneration on MRIs of the lumbar spine.

BACKGROUND: Magnetic resonance imaging (MRI) is used to detect degenerative changes of the lumbar spine. SpineNet (SN), a computer vision-based system, performs an automated analysis of degenerative features in MRI scans aiming to provide high accuracy, consistency and objectivity. This study evaluated SN's ratings compared with those of an expert radiologist. METHOD: MRIs of 882 patients (mean age, 72 ± 8.8 years) with degenerative spinal disorders from two previous trials carried out in our spine center between 2011 and 2019, were analyzed by an expert radiologist. Lumbar segments (L1/2-L5/S1) were graded for Pfirrmann Grades (PG), Spondylolisthesis (SL) and Central Canal Stenosis (CCS). SN's analysis for the equivalent parameters was generated. Agreement between methods was analyzed using kappa (κ), Spearman correlation (ρ) and Lin's concordance correlation (ρc) coefficients and class average accuracy (CAA). RESULTS: 4410 lumbar segments were analyzed. κ statistics showed moderate to substantial agreement in PG between the radiologist and SN depending on spinal level (range κ 0.63-0.77, all levels together 0.72; range CAA 45-68%, all levels 55%), slight to substantial agreement for SL (range κ 0.07-0.60, all levels 0.63; range CAA 47-57%, all levels 56%) and CCS (range κ 0.17-0.57, all levels 0.60; range CAA 35-41%, all levels 43%). SN tended to record more pathological features in PG than did the radiologist whereas the contrary was the case for CCS. SL showed an even distribution between methods. CONCLUSION: SN is a robust and reliable tool with the ability to grade degenerative features such as PG, SL or CCS in lumbar MRIs with moderate to substantial agreement compared to the current gold-standard, the radiologist. It is a valuable alternative for analyzing MRIs from large cohorts for diagnostic and research purposes.

The Clinical Effectiveness of a Physiotherapy Delivered Physical and Psychological Group Intervention for Older Adults With Neurogenic Claudication: The BOOST Randomized Controlled Trial.

BACKGROUND: Neurogenic claudication (NC) is a debilitating spinal condition affecting older adults' mobility and quality of life. METHODS: A randomized controlled trial of 438 participants evaluated the effectiveness of a physical and psychological group intervention (BOOST program) compared to physiotherapy assessment and tailored advice (best practice advice [BPA]) for older adults with NC. Participants were identified from spinal clinics (community and secondary care) and general practice records and randomized 2:1 to the BOOST program or BPA. The primary outcome was the Oswestry Disability Index (ODI) at 12 months. Data were also collected at 6 months. Other outcomes included ODI walking item, 6-minute walk test (6MWT), and falls. The primary analysis was intention-to-treat. RESULTS: The average age of participants was 74.9 years (standard deviation [SD] 6.0) and 57% (246/435) were female. There was no significant difference in ODI scores between treatment groups at 12 months (adjusted mean difference [MD]: -1.4 [95% confidence intervals (CI) -4.03, 1.17]), but, at 6 months, ODI scores favored the BOOST program (adjusted MD: -3.7 [95% CI -6.27, -1.06]). At 12 months, the BOOST program resulted in greater improvements in walking capacity (6MWT MD: 21.7m [95% CI 5.96, 37.38]) and ODI walking item (MD: -0.2 [95% CI -0.45, -0.01]) and reduced falls risk (odds ratio: 0.6 [95% CI 0.40, 0.98]) compared to BPA. No serious adverse events were related to either treatment. CONCLUSIONS: The BOOST program substantially improved mobility for older adults with NC. Future iterations of the program will consider ways to improve long-term pain-related disability. Clinical Trials Registration Number: ISRCTN12698674.

Current perspectives on the role of biomechanical loading and genetics in development of disc degeneration and low back pain; a narrative review.

Degenerative changes in the disc have long been of interest; they are thought to be strongly associated with low back pain and caused by inappropriate loading or through injury. However, independent of the magnitude of occupational spinal loading, twin studies find that the heritability of lumbar disc degeneration is 34-74%. This finding has led to intensive searches for susceptibility genes; some genes associated with disc degeneration have been identified, though all with small effects on the degenerative process. The complex nature of degenerative changes suggests that many different genes are involved, and that interactions with environmental factors are influential in progression of degeneration. Low back pain itself also appears heritable (30-46%). The most important clinical question though, is not how discs degenerate but is disc degeneration related to low back pain. Imaging studies find many people with degenerate discs or even with discs showing pathological features such as herniations, are asymptomatic. However results are obscured by the lack of consistent definitions of the phenotypes of disc degeneration and of low back pain. Epidemiological studies could help disentangle these complex relationships, but they will only be successful once consistent classifications and phenotypes of both disc degeneration and low back pain are developed.

Leptin and the intervertebral disc: a biochemical link exists between obesity, intervertebral disc degeneration and low back pain-an in vitro study in a bovine model.

PURPOSE: The aim of this study was to identify the effects of leptin upon the intervertebral disc (IVD) and to determine whether these responses are potentiated within an environment of existing degeneration. Obesity is a significant risk factor for low back pain (LBP) and IVD degeneration. Adipokines, such as leptin, are novel cytokines produced primarily by adipose tissue and have been implicated in degradative and inflammatory processes. Obese individuals are known to have higher concentrations of serum leptin, and IVD cells express leptin receptors. We hypothesise that adipokines, such as leptin, mediate a biochemical link between obesity, IVD degeneration and LBP. METHODS: The bovine intervertebral disc was used as a model system to investigate the biochemical effects of obesity, mediated by leptin, upon the intervertebral disc. Freshly isolated cells, embedded in 3D alginate beads, were subsequently cultured under varying concentrations of leptin, alone or together with the pro-inflammatory cytokines TNF-α, IL-1ß or IL-6. Responses in relation to production of nitric oxide, lactate, glycosaminoglycans and expression of anabolic and catabolic genes were analysed. RESULTS: Leptin influenced the cellular metabolism leading particularly to greater production of proteases and NO. Addition of leptin to an inflammatory environment demonstrated a marked deleterious synergistic effect with greater production of NO, MMPs and potentiation of pro-inflammatory cytokine production. CONCLUSIONS: Leptin can initiate processes involved in IVD degeneration. This effect is potentiated in an environment of existing degeneration and inflammation. Hence, a biochemical mechanism may underlie the link between obesity, intervertebral disc degeneration and low back pain. These slides can be retrieved under Electronic Supplementary Material.

The Association Between Body Mass Index (BMI) and Back or Leg Pain in Patients With Spinal Conditions: Results from the Genodisc Study.

STUDY DESIGN: A prospective observational study. OBJECTIVE: The aim of this study was to identify the relationship between obesity, quantified by body mass index (BMI), and both back and leg pain in spinal patients. SUMMARY OF BACKGROUND DATA: Obesity and back pain are massive public health problems. Given the poor correlation between pain and a pathological change in the spine, further investigation is required into other, nonpathological predictors such as obesity. METHODS: The Genodisc Study was one of the largest cross-sectional studies of patients presenting to tertiary spinal units and recruited from six centers in four European countries. In total, 2636 patients were recruited over a 5-year period between 2008 and 2013. Both back and leg pain were scored by patients in the range of 0 to 10. Linear regression was used to model the relationship between BMI and pain. Potential confounders included in the model were age, Zung Depression score, episodes of sport, gender, disability benefit, family history, previous surgery, smoking status, work type, clinical diagnosis, and relevant comorbidities. Back and leg pain outcomes were modeled separately. RESULTS: The study included 1160 men and 1349 women with a mean age of 50.9 years and mean BMI of 27.2 kg/m. In our fully adjusted model, a 5-point increase in BMI was associated with greater leg [0.19 units (95% confidence interval 0.08-0.31)] but not back [0.10 units (95% CI -0.02 to 0.22)] pain scores. Although this relationship was statically significant, given the small magnitude of the relationship, the clinical significance is limited. Similarly, female gender, heavy workload, rheumatoid arthritis, previous spine surgery, and depression were associated with higher back and leg pain. CONCLUSION: In this large observational study of spine patients presenting to tertiary European centers, obesity, as measured by increased BMI, was associated with greater leg pain. LEVEL OF EVIDENCE: 2.

Consensus at last! Long-term results of all randomized controlled trials show that fusion is no better than non-operative care in improving pain and disability in chronic low back pain.

Commentary On: Hedlund R, Johansson C, Hagg O, Fritzell P, Tullberg T. Swedish Lumbar Spine Study Group. The long-term outcome of lumbar fusion in the Swedish lumbar spine study. Spine J 2016;16:579-87 (in this issue).

Determination of the Oswestry Disability Index score equivalent to a "satisfactory symptom state" in patients undergoing surgery for degenerative disorders of the lumbar spine-a Spine Tango registry-based study.

BACKGROUND CONTEXT: The achievement of a given change score on a valid outcome instrument is commonly used to indicate whether a clinically relevant change has occurred after spine surgery. However, the achievement of such a change score can be dependent on baseline values and does not necessarily indicate whether the patient is satisfied with the current state. The achievement of an absolute score equivalent to a patient acceptable symptom state (PASS) may be a more stringent measure to indicate treatment success. PURPOSE: This study aimed to estimate the score on the Oswestry Disability Index (ODI, version 2.1a; 0-100) corresponding to a PASS in patients who had undergone surgery for degenerative disorders of the lumbar spine. STUDY DESIGN/SETTING: This is a cross-sectional study of diagnostic accuracy using follow-up data from an international spine surgery registry. PATIENT SAMPLE: The sample includes 1,288 patients with degenerative lumbar spine disorders who had undergone elective spine surgery, registered in the EUROSPINE Spine Tango Spine Surgery Registry. OUTCOME MEASURES: The main outcome measure was the ODI (version 2.1a). METHODS: Surgical data and data from the ODI and Core Outcome Measures Index (COMI) were included to determine the ODI threshold equivalent to PASS at 1 year (±1.5 months; n=780) and 2 years (±2 months; n=508) postoperatively. The symptom-specific well-being item of the COMI was used as the external criterion in the receiver operating characteristic (ROC) analysis to determine the ODI threshold equivalent to PASS. Separate sensitivity analyses were performed based on the different definitions of an "acceptable state" and for subgroups of patients. JF is a copyright holder of the ODI. RESULTS: The ODI threshold for PASS was 22, irrespective of the time of follow-up (area under the curve [AUC]: 0.89 [sensitivity {Se}: 78.3%, specificity {Sp}: 82.1%] and AUC: 0.91 [Se: 80.7%, Sp: 85.6] for the 1- and 2-year follow-ups, respectively). Sensitivity analyses showed that the absolute ODI-22 threshold for the two follow-up time-points were robust. A stricter definition of PASS resulted in lower ODI thresholds, varying from 16 (AUC=0.89; Se: 80.2%, Sp: 82.0%) to 18 (AUC=0.90; Se: 82.4%, Sp: 80.4%) depending on the time of follow-up. CONCLUSIONS: An ODI score ≤22 indicates the achievement of an acceptable symptom state and can hence be used as a criterion of treatment success alongside the commonly used change score measures. At the individual level, the threshold could be used to indicate whether or not a patient with a lumbar spine disorder is a "responder" after elective surgery.

A proposed set of metrics for standardized outcome reporting in the management of low back pain.

BACKGROUND AND PURPOSE: Outcome measurement has been shown to improve performance in several fields of healthcare. This understanding has driven a growing interest in value-based healthcare, where value is defined as outcomes achieved per money spent. While low back pain (LBP) constitutes an enormous burden of disease, no universal set of metrics has yet been accepted to measure and compare outcomes. Here, we aim to define such a set. PATIENTS AND METHODS: An international group of 22 specialists in several disciplines of spine care was assembled to review literature and select LBP outcome metrics through a 6-round modified Delphi process. The scope of the outcome set was degenerative lumbar conditions. RESULTS: Patient-reported metrics include numerical pain scales, lumbar-related function using the Oswestry disability index, health-related quality of life using the EQ-5D-3L questionnaire, and questions assessing work status and analgesic use. Specific common and serious complications are included. Recommended follow-up intervals include 6, 12, and 24 months after initiating treatment, with optional follow-up at 3 months and 5 years. Metrics for risk stratification are selected based on pre-existing tools. INTERPRETATION: The outcome measures recommended here are structured around specific etiologies of LBP, span a patient's entire cycle of care, and allow for risk adjustment. Thus, when implemented, this set can be expected to facilitate meaningful comparisons and ultimately provide a continuous feedback loop, enabling ongoing improvements in quality of care. Much work lies ahead in implementation, revision, and validation of this set, but it is an essential first step toward establishing a community of LBP providers focused on maximizing the value of the care we deliver.

The Oswestry Disability Index (version 2.1a): validation of a Dutch language version.

STUDY DESIGN: A cross-sectional study on baseline data. OBJECTIVE: To translate the Oswestry Disability Index (ODI) version 2.1a into the Dutch language and to validate its use in a cohort of patients with chronic low back pain in secondary spine care. SUMMARY OF BACKGROUND DATA: Patient-reported outcome measures (PROMs) are commonly accepted to evaluate the outcome of spine interventions. Functional status is an important outcome in spine research. The ODI is a recommended condition-specific patient-reported outcome measure used to evaluate functional status in patients with back pain. As yet, no formal translated Dutch version exists. METHODS: The ODI was translated according to established guidelines. The final version was built into the electronic web-based system in addition with the Roland Morris Disability Questionnaire, the numeric rating scale for pain severity, 36-Item Short Form Health Survey Questionnaire for quality of life, and the hospital anxiety and depression scale. Baseline data were used of 244 patients with chronic low back pain who participated in a combined physical and psychological program. Floor and ceiling effects, internal consistency, and the construct validity were evaluated using quality criteria. RESULTS: The mean ODI (standard deviation) was 39.6 (12.3); minimum 6, maximum 70. Most of the participants (88%) were moderately to severely disabled. Factor analysis determined a 1-factor structure (36% explained variance) and the homogeneity of ODI items is shown (Cronbach α = 0.79). The construct validity is supported as all (6:6) the a priori hypotheses were confirmed. Moreover, the ODI and Roland Morris Disability Questionnaire, showed a strong significant correlation (r = 0.68, P < 0.001) and an overlap: mean difference of -18 (95% limits of agreement: -44 to 8). CONCLUSION: The Dutch ODI version 2.1a is a valid and valuable tool for the measurement of functional status and disability among Dutch patients with chronic low back pain. This translated condition-specific patient-reported outcome measure version is recommended for use in future back pain research and to evaluate outcome of back care in the Netherlands.

ISSLS Prize winner: Long-term follow-up suggests spinal fusion is associated with increased adjacent segment disc degeneration but without influence on clinical outcome: results of a combined follow-up from 4 randomized controlled trials.

STUDY DESIGN: Cross-sectional analysis of long-term follow-up (LTFU) data from 4 randomized controlled trials of operative versus nonoperative treatment for chronic low back pain. OBJECTIVE: To examine the influence of spinal fusion on adjacent segment disc space height as an indicator of disc degeneration at LTFU. SUMMARY OF BACKGROUND DATA: There is ongoing debate as to whether adjacent segment disc degeneration results from the increased mechanical stress of fusion. METHODS: Plain standing lateral radiographs were obtained at LTFU (mean, 13 ± 4 yr postrandomization) in 229 of 464 (49%) patients randomized to surgery and 140 of 303 (46%), to nonoperative care. Disc space height and posteroanterior displacement were measured for each lumbar segment using a validated computer-assisted distortion compensated roentgen analysis technique. Values were reported in units of standard deviations above or below age and sex-adjusted normal values. Patient-rated outcomes included the Oswestry Disability Index and pain scales. RESULTS: Radiographs were usable in 355 of 369 (96%) patients (259 fusion and 96 nonoperative treatment). Both treatment groups showed significantly lower values for disc space height of the adjacent segment than norm values. There was a significant difference between treatment groups for the disc space height of the cranial adjacent segment (in both as-treated and intention-to-treat analyses). The mean treatment effect of fusion on adjacent segment disc space height was -0.44 SDs (95% CI, -0.77 to -0.11; P = 0.01; as-treated analysis); there was no group difference for posteroanterior displacement (0.18 SDs, 95% confidence interval, -0.28 to 0.64, P = 0.45). Adjacent level disc space height and posteroanterior displacement were not correlated with Oswestry Disability Index or pain scores at LTFU (r = 0.010-0.05; P > 0.33). CONCLUSION: Fusion was associated with lower disc space height at the adjacent segment after an average of 13 years of FU. The reduced disc space height had no influence on patient self-rated outcomes (pain or disability). LEVEL OF EVIDENCE: 2.

Disc cell therapies: critical issues.

BACKGROUND: Disc cell therapies, in which cells are injected into the degenerate disc in order to regenerate the matrix and restore function, appear to be an attractive, minimally invasive method of treatment. Interest in this area has stimulated research into disc cell biology in particular. However, other important issues, some of which are discussed here, need to be considered if cell-based therapies are to be brought to the clinic. PURPOSE: Firstly, a question which is barely addressed in the literature, is how to identify patients with 'degenerative disc disease' who would benefit from cell therapy. Pain not disc degeneration is the symptom which drives patients to the clinic. Even though there are associations between back pain and disc degeneration, many people with even severely degenerate discs, with herniated discs or with spinal stenosis, are pain-free. It is not possible using currently available techniques to identify whether disc repair or regeneration would remove symptoms or prevent symptoms from occurring in future. Moreover, the repair process in human discs is very slow (years) because of the low cell density which can be supported nutritionally even in healthy human discs. If repair is necessary for relief of symptoms, questions regarding quality of life and rehabilitation during this long process need consideration. Also, some serious technical issues remain. Finding appropriate cell sources and scaffolds have received most attention, but these are not the only issues determining the feasibility of the procedure. There are questions regarding the safety of implanting cells by injection through the annulus whether the nutrient supply to the disc is sufficient to support implanted cells and whether, if cells are able to survive, conditions in a degenerate human disc will allow them to repair the damaged tissue. CONCLUSIONS: If cell therapy for treatment of disc-related disorders is to enter the clinic as a routine treatment, investigations must examine the questions related to patient selection and the feasibility of achieving the desired repair in an acceptable time frame. Few diagnostic tests that examine whether cell therapies are likely to succeed are available at present, but definite exclusion criteria would be evidence of major disc fissures, or disturbance of nutrient pathways as measured by post-contrast MRI.

Predictive factors for successful clinical outcome 1 year after an intensive combined physical and psychological programme for chronic low back pain.

PURPOSE: The aim of this longitudinal study is to determine the factors which predict a successful 1-year outcome from an intensive combined physical and psychological (CPP) programme in chronic low back pain (CLBP) patients. METHODS: A prospective cohort of 524 selected consecutive CLBP patients was followed. Potential predictive factors included demographic characteristics, disability, pain and cognitive behavioural factors as measured at pre-treatment assessment. The primary outcome measure was the oswestry disability index (ODI). A successful 1-year follow-up outcome was defined as a functional status equivalent to 'normal' and healthy populations (ODI ≤22). The 2-week residential programme fulfills the recommendations in international guidelines. For statistical analysis we divided the database into two equal samples. A random sample was used to develop a prediction model with multivariate logistic regression. The remaining cases were used to validate this model. RESULTS: The final predictive model suggested being 'in employment' at pre-treatment [OR 3.61 (95 % CI 1.80-7.26)] and an initial 'disability score' [OR 0.94 (95 % CI 0.92-0.97)] as significant predictive factors for a successful 1-year outcome (R (2) = 22 %; 67 % correctly classified). There was no predictive value from measures of psychological distress. CONCLUSION: CLBP patients who are in work and mild to moderately disabled at the start of a CPP programme are most likely to benefit from it and to have a successful treatment outcome. In these patients, the disability score falls to values seen in healthy populations. This small set of factors is easily identified, allowing selection for programme entry and triage to alternative treatment regimes.

Why are there different versions of the Oswestry Disability Index?

This article updates readers on the current state of the Oswestry Disability Index (ODI) and the impact of unvalidated versions. The ODI is now licensed to the Mapi Research Trust in order to preserve a standard version in English and in validated translations. A proposed threshold of "normality" is potentially helpful as an outcome for both audit and research. There is an application of the sex section as a quality measure in Germany. The ODI is an important international shared resource for clinicians and investigators and should not be abused. Its current status will not be enhanced by further modification. It is now registered with the International Consortium for Health Outcomes Measurement as a standard outcome measure.

Comparison of spinal fusion and nonoperative treatment in patients with chronic low back pain: long-term follow-up of three randomized controlled trials.

BACKGROUND CONTEXT: Chronic low back pain (cLBP) represents a major challenge to our health care systems. The relative efficacy of surgery over nonoperative treatment for the treatment of cLBP remains controversial, and little is known of the long-term comparative outcomes. PURPOSE: To compare the clinical outcome at long-term follow-up (LTFU) of patients who were randomized with either spinal fusion or multidisciplinary cognitive-behavioral and exercise rehabilitation for cLBP. STUDY DESIGN/SETTING: Long-term clinical follow-up of three multicenter randomized controlled trials (RCTs) of surgery (instrumented or noninstrumented fusion, stabilization) versus nonoperative treatment (multidisciplinary cognitive-behavioral and exercise rehabilitation) in Norway and the United Kingdom. PATIENT SAMPLE: A total of 473 patients with cLBP of at least 1 year's duration who were all considered candidates for spinal fusion. OUTCOME MEASURES: The primary outcome was the Oswestry Disability Index (ODIv2.1a for the United Kingdom and ODIv1 for Norway) score measured at LTFU. Secondary outcomes included visual analog scale (VAS) pain intensity, pain frequency, pain medication use, work status, EuroQol VAS for health-related quality of life, satisfaction with care, and global treatment outcome at LTFU. METHODS: Patients who consented to LTFU (average 11.4 [range 8-15] years after the initial treatment) completed the outcome questionnaires. RESULTS: Of 473 enrolled patients, 261 (55%) completed LTFU, 140/242 patients randomized to receive surgery and 121/231 randomized to receive multidisciplinary cognitive-behavioral and exercise rehabilitation. The intention-to-treat analysis showed no statistically or clinically significant differences between treatment groups for ODI scores at LTFU (adjusted for baseline ODI, previous surgery, duration of LBP, sex, age, and smoking habit): the mean adjusted treatment effect of fusion was -0.7 points on the 0-100 ODI scale (95% confidence interval [CI], -5.5 to 4.2). An as-treated analysis similarly demonstrated no advantage of surgery (treatment effect, -0.8 points on the ODI (95% CI, -5.9 to 4.3). The results for the secondary outcomes were largely consistent with those of the ODI, showing no relevant group differences. CONCLUSIONS: After an average of 11 years follow-up, there was no difference in patient self-rated outcomes between fusion and multidisciplinary cognitive-behavioral and exercise rehabilitation for cLBP. The results suggest that, given the increased risks of surgery and the lack of deterioration in nonoperative outcomes over time, the use of lumbar fusion in cLBP patients should not be favored in health care systems where multidisciplinary cognitive-behavioral and exercise rehabilitation programmes are available.

Intervertebral disk nutrition: a review of factors influencing concentrations of nutrients and metabolites.

The biomechanical behavior of the intervertebral disk ultimately depends on the viability and activity of a small population of resident cells that make and maintain the disk's extracellular matrix. Nutrients that support these cells are supplied by the blood vessels at the disks' margins and diffuse through the matrix of the avascular disk to the cells. This article reviews pathways of nutrient supply to these cells; examines factors that may interrupt these pathways, and discusses consequences for disk cell survival, disk degeneration, and disk repair.