ISSLS PRIZE in Clinical Science 2023: comparison of degenerative MRI features of the intervertebral disc between those with and without chronic low back pain. An exploratory study of two large female populations using automated annotation.

OBJECTIVES: The relationship of degeneration to symptoms has been questioned. MRI detects apparently similar disc degeneration and degenerative changes in subjects both with and without back pain. We aimed to overcome these problems by re-annotating MRIs from asymptomatic and symptomatics groups onto the same grading system. METHODS: We analysed disc degeneration in pre-existing large MRI datasets. Their MRIs were all originally annotated on different scales. We re-annotated all MRIs independent of their initial grading system, using a verified, rapid automated MRI annotation system (SpineNet) which reported degeneration on the Pfirrmann (1-5) scale, and other degenerative features (herniation, endplate defects, marrow signs, spinal stenosis) as binary present/absent. We compared prevalence of degenerative features between symptomatics and asymptomatics. RESULTS: Pfirrmann degeneration grades in relation to age and spinal level were very similar for the two independent groups of symptomatics over all ages and spinal levels. Severe degenerative changes were significantly more prevalent in discs of symptomatics than asymptomatics in the caudal but not the rostral lumbar discs in subjects < 60 years. We found high co-existence of degenerative features in both populations. Degeneration was minimal in around 30% of symptomatics < 50 years. CONCLUSIONS: We confirmed age and disc level are significant in determining imaging differences between asymptomatic and symptomatic populations and should not be ignored. Automated analysis, by rapidly combining and comparing data from existing groups with MRIs and information on LBP, provides a way in which epidemiological and 'big data' analysis could be advanced without the expense of collecting new groups. LEVEL OF EVIDENCE I: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

The internal pressure and stress environment of the scoliotic intervertebral disc--a review.

The aetiology, in terms of both initiation and progression, of the deformity in idiopathic scoliosis is at present unclear. Even in neuromuscular cases, the mechanisms underlying progression are not fully elucidated. It is thought, however, that asymmetrical loading is involved in the progression of the disease, with evidence mainly from animal studies and modelling. There is, however, very little direct information as to the origin or mechanism of action of these forces in the scoliotic spine. This review describes the concept of intervertebral disc pressure or stress and examines possible measurement techniques. The biological and mechanical consequences of abnormalities in these parameters are described. Future possible studies and their clinical significance are also briefly discussed. Techniques of pressure measurement have culminated in the development of 'pressure profilometry', which provides stress profiles across the disc in mutually perpendicular axes. A hydrated intervertebral disc exhibits mainly hydrostatic behaviour. However, in pathological states such as degeneration and scoliosis, non-hydrostatic behaviour predominates and annular peaks of stress occur. Recent studies have shown that, in scoliosis, high hydrostatic pressures are seen with asymmetrical stresses from concave to convex sides. These abnormalities could influence both disc and endplate cellular activity directly, causing asymmetrical growth and matrix changes. In addition, disc cells could be influenced via nutritional changes consequent to end-plate calcification. Evidence suggests that the stress environment of the scoliotic disc is abnormal, probably generated by high and asymmetrical loading of non-muscular origin. If present in the scoliotic spine during daily activities, this could generate a positive feedback of cellular changes, resulting in curve progression. Future advances in understanding may rely on the development of computer models owing to the difficulties of in-vivo invasive measurements.

Development of a German version of the Oswestry Disability Index. Part 2: sensitivity to change after spinal surgery.

When functional scales are to be used as treatment outcome measures, it is essential to know how responsive they are to clinical change. This information is essential not only for clinical decision-making, but also for the determination of sample size in clinical trials. The present study examined the responsiveness of a German version of the Oswestry Disability Index version 2.1 (ODI) after surgical treatment for low back pain. Before spine surgery 63 patients completed a questionnaire booklet containing the ODI, along with a 0-10 pain visual analogue scale (VAS), the Roland Morris disability questionnaire, and Likert scales for disability, medication intake and pain frequency. Six months after surgery, 57 (90%) patients completed the same questionnaire booklet and also answered Likert-scale questions on the global result of surgery, and on improvements in pain and disability. Both the effect size for the ODI change score 6 months after surgery (0.87) and the area under the receiver operating characteristics (ROC) curve for the relative improvement in ODI score in relation to global outcome 6 months after surgery (0.90) indicated that the ODI showed good responsiveness. The ROC method revealed that a minimum reduction of the baseline (pre-surgery) ODI score by 18% (equal to a mean 8-point reduction in this patient group) represented the cut-off for indicating a "good" individual outcome 6 months after surgery (sensitivity 91.4% and specificity 82.4%). The German version of the ODI is a sensitive instrument for detecting clinical change after spinal surgery. Individual improvements after surgery of at least an 18% reduction on baseline values are associated with a good outcome. This figure can be used as a reliable guide for the determination of sample size in future clinical trials of spinal surgery.

Development of a German version of the Oswestry Disability Index. Part 1: cross-cultural adaptation, reliability, and validity.

Patient-orientated assessment methods are of paramount importance in the evaluation of treatment outcome. The Oswestry Disability Index (ODI) is one of the condition-specific questionnaires recommended for use with back pain patients. To date, no German version has been published in the peer-reviewed literature. A cross-cultural adaptation of the ODI for the German language was carried out, according to established guidelines. One hundred patients with chronic low-back pain (35 conservative, 65 surgical) completed a questionnaire booklet containing the newly translated ODI, along with a 0-10 pain visual analogue scale (VAS), the Roland Morris Disability Questionnaire, and Likert scales for disability, medication intake and pain frequency [to assess ODI's construct (convergent) validity]. Thirty-nine of these patients completed a second questionnaire within 2 weeks (to assess test-retest reliability). The intraclass correlation coefficient for the test-retest reliability of the questionnaire was 0.96. In test-retest, 74% of the individual questions were answered identically, and 21% just one grade higher or lower. The standard error of measurement (SEM) was 3.4, giving a "minimum detectable change" (MDC(95%)) for the ODI of approximately 9 points, i.e. the minimum change in an individual's score required to be considered "real change" (with 95% confidence) over and above measurement error. The ODI scores correlated with VAS pain intensity (r = 0.78, P < 0.001) and Roland Morris scores (r = 0.80, P < 0.001). The mean baseline ODI scores differed significantly between the surgical and conservative patients (P < 0.001), and between the different categories of the Likert scales for disability, medication use and pain frequency (in each case P < 0.001). Our German version of the Oswestry questionnaire is reliable and valid, and shows psychometric characteristics as good as, if not better than, the original English version. It should represent a valuable tool for use in future patient-orientated outcome studies in German-speaking lands.

Electrochemical measurement of transport into scoliotic intervertebral discs in vivo using nitrous oxide as a tracer.

STUDY DESIGN: An in vivo study measuring nitrous oxide concentrations in scoliotic intervertebral discs during surgery. OBJECTIVES: To determine pathways for nutrient transport into scoliotic human discs in vivo. SUMMARY OF BACKGROUND DATA: The intervertebral disc is the largest avascular structure in the body. Disc cells in the nucleus rely on the blood supply from the vertebral bodies for supply of nutrients and removal of waste. Loss of nutrient supply is thought to lead to disc degeneration, but solute transport has not been measured in vivo in humans. METHODS: We measured solute transport into the disc using N2O as a tracer, in 19 human discs from five patients with neuromuscular scoliosis (6-19 years of age) during surgery for correction of scoliotic deformities. During anesthesia N2O diffuses into the disc at a rate governed by effective permeability of the vertebral body-disc interface. Intradiscal N2O concentrations were measured amperometrically using silver needle microelectrodes, which were inserted into the discs once they were exposed by an anterior approach. RESULTS: For all spines N2O concentrations were very low in the disc at the curve apex (6% those expected from unimpeded diffusion) and, although still low, were significantly higher 2 discs below or above the apex. CONCLUSIONS: Because flux into the apical disc is most restricted, the decrease in solute transport is possibly induced by changes in mechanical stress on the disc; microfocal radiographs of a scoliotic spine suggest that increased endplate calcification could be partly responsible for limiting solute diffusion.

Intervertebral disc composition in neuromuscular scoliosis: changes in cell density and glycosaminoglycan concentration at the curve apex.

STUDY DESIGN: An analysis of the variation in glycosaminoglycan, water content, and cell density with disc level in patients with neuromuscular scoliosis. OBJECTIVES: To determine whether the composition of the apical disc differed from that of adjacent discs in the same spine. SUMMARY OF BACKGROUND DATA: Compositional differences between the convex and concave sides of scoliotic discs have been noted and are thought to be secondary to altered loading. However, there is little information on changes relative to the apex. METHODS: Intact wedges of disc obtained during anterior fusion procedures were taken from 23 discs of 6 patients with neuromuscular scoliosis. Radial profiles of glycosaminoglycan, water content, and cell density were measured. Concentrations were compared at a standard distance (5 mm) into the disc and plotted versus spinal level. RESULTS: Glycosaminoglycan and water content were lowest in the outer annulus and increased steadily toward the disc center, whereas the cell density was highest in the outer 2 mm, fell steeply and then remained constant. At 5 mm from the annulus edge, cell density was lowest in apical discs and, in most cases, was noticeably higher in adjacent discs of the same spine. At the same point, there was no consistent change in glycosaminoglycan/dry weight from disc to disc, indicating no significant proteoglycan loss. However, glycosaminoglycan/tissue water, and therefore swelling pressure, was highest in the apical discs, suggesting that these discs were the most heavily loaded. CONCLUSIONS: The loss of cells from the disc at the curve apex probably arose because this disc experiences greater mechanical stress or is more deformed than its neighbors. The decrease in cell density was not associated with major changes in tissue composition, possibly because rates of degradation and of synthesis were reduced, leaving the matrix largely unchanged.

The Oswestry Disability Index.

STUDY DESIGN: The Oswestry Disability Index (ODI) has become one of the principal condition-specific outcome measures used in the management of spinal disorders. This review is based on publications using the ODI identified from the authors' personal databases, the Science Citation Index, and hand searches of Spine and current textbooks of spinal disorders. OBJECTIVES: To review the versions of this instrument, document methods by which it has been validated, collate data from scores found in normal and back pain populations, provide curves for power calculations in studies using the ODI, and maintain the ODI as a gold standard outcome measure. SUMMARY OF BACKGROUND DATA: It has now been 20 years since its original publication. More than 200 citations exist in the Science Citation Index. The authors have a large correspondence file relating to the ODI, that is cited in most of the large textbooks related to spinal disorders. METHODS: All the published versions of the questionnaire were identified. A systematic review of this literature was made. The various reports of validation were collated and related to a version. RESULTS: Four versions of the ODI are available in English and nine in other languages. Some published versions contain misprints, and many omit the scoring system. At least 114 studies contain usable data. These data provide both validation and standards for other users and indicate the power of the instrument for detecting change in sample populations. CONCLUSIONS: The ODI remains a valid and vigorous measure and has been a worthwhile outcome measure. The process of using the ODI is reviewed and should be the subject of further research. The receiver operating characteristics should be explored in a population with higher self-report disabilities. The behavior of the instrument is incompletely understood, particularly in sensitivity to real change.

Variation with age in the pattern of type X collagen expression in normal and scoliotic human intervertebral discs.

The distribution and expression of type X collagen, a calcium-binding collagen, which is a marker of hypertrophic chondrocytes and thought to be involved in cartilage calcification, was examined in situ in nondegenerate (grade I or II) human discs taken at autopsy over a wide age range (fetal->80 years) and also in scoliotic discs removed at surgery. In the fetal vertebral column, type X collagen was strongly expressed in the hypertrophic chondrocytes of the endplate, but was not seen in other areas. In the cartilaginous endplate of adults, it was found over the whole age range examined, with intensity increasing with age. In the disc matrix itself, type X collagen was demonstrated around individual cells from all individuals older than 50 years, but not in any fetal or autopsy disc from individuals younger than 40 years. In scoliotic discs, however, focal type X collagen expression was seen in 3/8 patients younger than 40 years including one 12-year-old. No type X collagen was found in the outer annulus in any autopsy or scoliotic disc, supporting the idea that cells of the outer annulus are phenotypically distinct from cells of the inner annulus and the nucleus. Our results demonstrate for the first time that type X collagen is a possible gene product of the intervertebral disc cells and a potential biochemical component of the disc matrix. They indicate that with age or in scoliosis, some cells from the inner annulus or nucleus of the disc differentiate to the hypertrophic chondrocyte phenotype. This might be the initiating event for the abnormal calcification described in aged and scoliotic discs in other studies.

A fitness programme for patients with chronic low back pain: 2-year follow-up of a randomised controlled trial.

The aim of this study was to assess the long-term effect of a supervised fitness programme on patients with chronic low back pain. The design of the study was a single blind randomised controlled trial with follow-up, by postal questionnaire, 2 years after intervention. The Oswestry Low Back Pain Disability Index was used as the outcome measure to assess daily activity affected by back pain. Eighty-one patients with chronic low back pain, who were referred to the physiotherapy department of a National Health Service orthopaedic hospital, were randomised to either a supervised fitness programme or a control group. Patients in the intervention group and control group were taught specific exercises to be continued at home and referred to a backschool for back care education. In addition, the intervention group attended eight sessions of a supervised fitness programme. Sixty-two patients (76%) with a mean age of 37 years, returned the Oswestry Low Back Pain Disability Index questionnaire. Of these, 29 were in the intervention group and 31 in the control group. Patients in the intervention group demonstrated a mean reduction of 7.7% in the Oswestry Low Back Pain Disability Index score (95% confidence interval of mean paired difference 3.9, 11.6 P < 0.001), compared with only 2.4% in the control group (95% confidence interval of mean paired difference -2.0, 6.9 P > 0.05). Between group comparisons demonstrated a statistically significant difference in disability scores between the treatment and control group (mean difference 5.8, 95% confidence interval 0.3, 11.4 P < 0.04). This study supports the current trend towards a more active treatment approach to low back pain. We have demonstrated clinical effectiveness of a fitness programme 2 years after treatment but this needs to be replicated in a larger study which should include a cost effectiveness analysis, further analysis of objective functional status and a placebo intervention group.

Oxygen and lactate concentrations measured in vivo in the intervertebral discs of patients with scoliosis and back pain.

STUDY DESIGN: Oxygen concentrations in intervertebral discs were measured in 10 patients during discography and in 13 patients with scoliosis and 11 patients with back pain during spinal surgery. Lactate concentration profiles were measured in 12 of these discs. The discs were graded for degeneration by magnetic resonance imaging and histology where possible. OBJECTIVES: To determine if oxygen and lactate levels in human discs vary with degree of degeneration. Failure of nutrient transport is thought to lead to disc degeneration. SUMMARY OF BACKGROUND DATA: The disc is avascular. Oxygen is used by the disc cells, and lactate is produced. Low oxygen and high lactate concentrations have been measured in the center of healthy animal discs. METHODS: Oxygen concentrations were measured amprometrically. The sterilized gold-needle electrode was introduced into the disc during discography or after the disc was exposed surgically via an anterior approach. Concentration profiles of each disc took approximately 5 minutes to measure. Lactate concentrations were measured biochemically on the excised disc segment. RESULTS: Oxygen concentrations were highest at the disc surface and fell toward the center. Lactate concentrations showed the reverse profile. Oxygen levels were very variable, ranging from 5-150 mm Hg in the center of the nucleus. No correlation was seen with age, pathology, or degree of degeneration. Lactate concentrations ranged for the most part from 2 mmol/L to 6 mmol/L. CONCLUSIONS: Concentrations of metabolites depend on cellular activity and on transport of the metabolite between the blood supply and the cell. The correlation between degeneration and nutrition cannot be determined only from metabolite concentrations; measurements of metabolic activity and nutrient transport rates also are required.

Early detection of progression in adolescent idiopathic scoliosis by measurement of changes in back shape with the Integrated Shape Imaging System scanner.

STUDY DESIGN: A retrospective study of 78 patients with right thoracic idiopathic scoliosis was done. OBJECTIVES: To evaluate the reliability of the integrated Shape Imaging System scan (Oxford Metrics Ltd, Oxford, UK) in detecting progression of scoliosis and the use of back shape data in predicting scoliosis progression. SUMMARY OF BACKGROUND DATA: At first presentation and every 3-6 months during the follow-up period, all patients underwent integrated Shape Imaging System scans and radiographic examinations, from which the Cobb angle was measured. The follow-up period was 18-49 months (mean = 31.4 months). METHODS: Patients were divided into three groups according to the severity and progression of the Cobb angle. The spinal fusion, brace, and observation groups were compared using analysis of variance and the student's t test to detect significant differences among groups in the progression of deformity as measured by the integrated Shape Imaging System parameters and the Cobb angle. RESULTS: Three of the Integrated Shape Imaging System parameters detected significant progression in the spinal fusion group 1 year earlier than the Cobb angle. Only one of the Integrated Shape Imaging System parameters detected a significant difference in progression between the brace and observation groups. CONCLUSIONS: The Integrated Shape Imaging System technique demonstrated significant changes in this group of patients with progressive scoliosis. Serial measurements of back surface shape, particularly the size of the rib hump, may be predictive of progression. Serial Integrated Shape Imaging System scanning has advantages over serial radiography in the management of idiopathic scoliosis in addition to the avoidance of exposure to ionizing radiation.

Two-level intervertebral disc herniation in an adolescent.

A two-level intervertebral disc prolapse is a rare circumstance in adolescents. We describe the case of a 19-year-old man who suffered a deceleration traum and developed simultaneous large intervertebral disc herniations at L4/5 and L5/S1. The aetiology is discussed and, in accordance with the current literature, it is pointed out that clinical findings due to intervertebral disc herniations in young people do not necessarily correspond with the extent of the disease.

Randomised controlled trial for evaluation of fitness programme for patients with chronic low back pain.

OBJECTIVE: To evaluate a progressive fitness programme for patients with chronic low back pain. DESIGN: Single blind randomised controlled trial. Assessments were carried out before and after treatment by an observer blinded to the study and included a battery of validated measures. All patients were followed up by postal questionnaire six months after treatment. SETTING: Physiotherapy department of orthopaedic hospital. SUBJECTS: 81 patients with chronic low back pain referred from orthopaedic consultants for physiotherapy. The patients were randomly allocated to a fitness programme or control group. INTERVENTION: Both groups were taught specific exercises to carry out at home and referred to a back-school for education in back care. Patients allocated to the fitness class attended eight exercise classes over four weeks in addition to the home programme and backschool. RESULTS: Significant differences between the groups were shown in the changes before and after treatment in scores on the Oswestry low back pain disability index (P < 0.005), pain reports (sensory P < 0.05 and affective P < 0.005), self efficacy reports (P < 0.05), and walking distance (P < 0.005). No significant differences between the groups were found by the general health questionnaire or questionnaire on pain locus of control. A benefit of about 6 percentage points on the disability index was maintained by patients in the fitness group at six months. CONCLUSION: There is a role for supervised fitness programmes in the management of moderately disabled patients with chronic low back pain. Further clinical trials, however, need to be established in other centres to confirm these findings.

Quantifying the cosmetic defect of adolescent idiopathic scoliosis.

Cosmesis is important in the treatment of adolescent idiopathic scoliosis patients. The aim of this study was to quantify the cosmetic defect using parameters of the ISIS (Oxford Metrics Ltd., Oxford, England) scan. Ten nonmedical judges scored photographs of 100 adolescent idiopathic scoliosis patients based on cosmetic criteria. This Cosmetic Spinal Score proved to be a reliable figure. The Cosmetic Spinal Score was then compared with ISIS parameters and the Cobb angle. An equation based on ISIS parameters was developed, which could predict Cosmetic Spinal Score with sufficient reproducibility to have a useful clinical application. Bracing reduced the rib hump but not enough to improve the cosmetic appearance. Spinal fusion and Harrington instrumentation improved all measured parameters influencing physical appearance.

Acute pericardial tamponade complicating spinal surgery in a child with Duchenne muscular dystrophy.

A hitherto unrecognised problem of pericardial tamponade complicating spinal surgery in a child with Duchenne muscular dystrophy is reported in this paper.

1989 Volvo Award in clinical sciences. Reproducibility of physical signs in low-back pain.

The reproducibility between observers of physical signs in patients with low-back pain was investigated. Fifty patients were examined by two surgeons and another sample of 33 patients was examined by a surgeon and a physiotherapist. Continuous data on five signs were analyzed by Pearsons' correlation coefficient, and binary data on 54 signs were analyzed by the Kappa agreement coefficient. Reliable signs consisted of measurements of lordosis and flexion range, determination of pain on flexion and lateral bend, nearly all measurements associated with the straight leg raising test, determination of pain location in the thigh and legs, and determination of sensory changes in the legs. Signs of root tension showed better agreement when qualified with a description of where the pain was experienced. Bony tenderness was more reliable than soft tissue tenderness.