The use of the Core Yellow Flags Index for the assessment of psychosocial distress in patients undergoing surgery of the cervical spine.

BACKGROUND: Psychosocial distress (the presence of yellow flags) has been linked to poor outcomes in spine surgery. The Core Yellow Flags Index (CYFI), a short instrument assessing the 4 main yellow flags, was developed for use in patients undergoing lumbar spine surgery. This study evaluated its ability to predict outcome in patients undergoing cervical spine surgery. METHODS: Patients with degenerative spinal disorders (excluding myelopathy) operated in one centre, from 2015 to 2019, were asked to complete the CYFI at baseline and the Core Outcome Measures Index (COMI) at baseline and 3 and 12 months after surgery. The relationship between CYFI and COMI scores at baseline as well as the predictive ability of the CYFI on the COMI follow-up scores were tested using structural equation modelling. RESULTS: From 731 eligible patients, 547 (61.0 ± 12.5 years; 57.2% female) completed forms at all three timepoints. On a cross-sectional basis, preoperative CYFI and COMI scores were highly correlated (ß = 0.54, in men and 0.51 in women; each p < 0.001). CYFI added significantly and independently to the prediction of COMI at 3 months' FU in men (ß = 0.36) and 12 months' FU in men and women (both ß = 0.20) (all p < 0.001). CONCLUSION: The CYFI had a low to moderate but significant and independent association with cervical spine surgery outcomes. Implementing the CYFI in the preoperative workup of these patients could help refine outcome predictions and better manage patient expectations.

Does loss to follow-up lead to an overestimation of treatment success? Findings from a spine surgery registry of over 15,000 patients.

PURPOSE: Patient-reported outcome measures (PROMs) are integral to the assessment of treatment success, but loss to follow-up (attrition) may lead to bias in the results reported. We sought to evaluate the extent, nature and implications of attrition in a long-established, single-centre spine registry. METHODS: The registry contained the data of 15,264 consecutive spine surgery patients. PROMs included the Core Outcome Measures Index (COMI) and a rating of the Global Treatment Outcome (GTO) and Satisfaction with Care. Baseline characteristics associated with returning a 12-month PROM (= "responder") were analysed (logistic regression). The 3-month outcomes of 12-month responders versus 12-month non-responders were compared (ANOVA and Chi-square). RESULTS: In total, 14,758/15,264 (97%) patients (60 ± 17y; 46% men) had consented to the use of their registry data for research. Preoperative, 3-month post-operative and 12-month post-operative PROMs were returned by 91, 90 and 86%, respectively. Factors associated with being a 12-month responder included: greater age, born in the country of the study, no private/semi-private insurance, better baseline status (lower COMI score), fewer previous surgeries, less comorbidity and no perioperative medical complications. 12-month non-responders had shown significantly worse outcomes in their 3-month PROMs than had 12-month responders (respectively, 66% vs 80% good GTO ("treatment helped/helped a lot"); 77% vs 88% satisfied/very satisfied; and 49% vs 63% achieved MCIC on COMI). CONCLUSION: Although attrition in this cohort was relatively low, 12-month non-responders displayed distinctive characteristics and their early outcomes were significantly worse than those of 12-month responders. If loss to follow-up is not addressed, treatment success will likely be overestimated, with erroneously optimistic results being reported.

Quality metrics in adult spinal deformity surgery over the last decade: a combined analysis of the largest prospective multicenter data sets.

OBJECTIVE: The reported rate of complications and cost of adult spinal deformity (ASD) surgery, associated with an exponential increase in the number of surgeries, cause alarm among healthcare payers and providers worldwide. The authors conjointly analyzed the largest prospective available ASD data sets to define trends in quality-of-care indicators (complications, reinterventions, and health-related quality of life [HRQOL] outcomes) since 2010. METHODS: This is an observational prospective longitudinal cohort study. Patients underwent surgery between January 2010 and December 2016, with > 2 years of follow-up data. Demographic, surgical, radiological, and HRQOL (i.e., Oswestry Disability Index, SF-36, Scoliosis Research Society-22r) data obtained preoperatively and at 3, 6, 12, and 24 months after surgery were evaluated. Trends and changes in indicators were analyzed using local regression (i.e., locally estimated scatterplot smoothing [LOESS]) and adjusted odds ratio (OR). RESULTS: Of the 2286 patients included in the 2 registries, 1520 underwent surgery between 2010 and 2016. A total of 1151 (75.7%) patients who were treated surgically at 23 centers in 5 countries met inclusion criteria. Patient recruitment increased progressively (2010-2011 vs 2015-2016: OR 1.64, p < 0.01), whereas baseline clinical characteristics (age, American Society of Anesthesiologists class, HRQOL scores, sagittal deformity) did not change. Since 2010 there has been a sustained reduction in major and minor postoperative complications observed at 90 days (major: OR 0.59; minor: OR 0.65; p < 0.01); at 1 year (major: OR 0.52; minor: 0.75; p < 0.01); and at 2 years of follow-up (major: OR 0.4; minor: 0.80; p < 0.01) as well as in the 2-year reintervention rate (OR 0.41, p < 0.01). Simultaneously, there has been a slight improvement in the correction of sagittal deformity (i.e., pelvic incidence-lumbar lordosis mismatch: OR 1.11, p = 0.19) and a greater gain in quality of life (i.e., Oswestry Disability Index 26% vs 40%, p = 0.02; Scoliosis Research Society-22r, self-image domain OR 1.16, p = 0.13), and these are associated with a progressive reduction of surgical aggressiveness (number of fused segments: OR 0.81, p < 0.01; percent pelvic fixation: OR 0.66, p < 0.01; percent 3-column osteotomies: OR 0.63, p < 0.01). CONCLUSIONS: The best available data show a robust global improvement in quality metrics in ASD surgery over the last decade. Surgical complications and reoperations have been reduced by half, while improvement in disability increased and correction rates were maintained, in patients with similar baseline characteristics.

Development of the "Core Yellow Flags Index" (CYFI) as a brief instrument for the assessment of key psychological factors in patients undergoing spine surgery.

BACKGROUND: Depression, anxiety, catastrophising, and fear-avoidance beliefs are key "yellow flags" (YFs) that predict a poor outcome in back patients. Most surgeons acknowledge the importance of YFs but have difficulty assessing them due to the complexity of the instruments used for their measurement and time constraints during consultations. We performed a secondary analysis of existing questionnaire data to develop a brief tool to enable the systematic evaluation of YFs and then tested it in clinical practice. METHODS: The following questionnaire datasets were available from a total of 932 secondary/tertiary care patients (61 ± 16 years; 51% female): pain catastrophising (N = 347); ZUNG depression (N = 453); Hospital Anxiety and Depression Scale (anxiety subscale) (N = 308); fear-avoidance beliefs (N = 761). The single item that best represented the full-scale score was identified, to form the 4-item "Core Yellow Flags Index" (CYFI). 2422 patients (64 ± 16 years; 54% female) completed CYFI and a Core Outcome Measures Index (COMI) before lumbar spine surgery, and a COMI 3 and 12 months later (FU). RESULTS: The item-total correlation for each item with its full-length questionnaire was: 0.77 (catastrophising), 0.67 (depression), 0.69 (anxiety), 0.68 (fear-avoidance beliefs). Cronbach's α for the CYFI was 0.79. Structural equation modelling showed CYFI uniquely explained variance (p < 0.001) in COMI at both the 3- and 12-month FUs (ß = 0.11 (women), 0.24 (men); and ß = 0.13 (women), ß = 0.14 (men), respectively). CONCLUSION: The 4-item CYFI proved to be a simple, practicable tool for routinely assessing key psychological attributes in spine surgery patients and made a relevant contribution in predicting postoperative outcome. CYFI's items were similar to those in the "STarT Back screening tool" used in primary care to triage patients into treatment pathways, further substantiating its validity. Wider use of CYFI may help improve the accuracy of predictive models derived using spine registry data.

Back Pain and Its Change After Surgery in Adolescents and Young Adults With Idiopathic Scoliosis.

STUDY DESIGN: A retrospective analysis of prospectively collected data from patients aged 12-30 years, operated for AIS in our hospital from 2005 to 2014 and registered in our local patient outcomes database linked to EUROSPSINE's Spine Tango Registry. OBJECTIVES: To investigate whether in patients with AIS and notable back pain surgery is associated with significant pain relief and whether age influences outcome. SUMMARY OF BACKGROUND DATA: Few studies have investigated the association between adolescent idiopathic scoliosis and back pain and the influence of age on the relief of back pain after surgical correction of the deformity. METHODS: Preoperatively and up to two years' postoperatively, patients completed the Core Outcome Measures Index, which includes two 0-10 scales for back pain and leg/buttock pain. A score of 4/10 or more is considered "relevant pain." RESULTS: We identified 85 patients with AIS (74 (87%) females) in the database; 60 were aged 12-18 years (mean 15.5 ± 1.7 years) and 25 were 19-30 years (mean 22.5 ± 3.1 years). There were no significant differences (p > .05) between the age groups for coronal Cobb angles of the main curves or Lenke curve types, and these curves showed no correlation with pain intensity (p > .05). Back pain was correlated with age (r = 0.31, p = .004). Preoperatively, 42% patients had a back pain score of ≥4/10 (52% in adults, 38% in adolescents). Just 8% patients had a leg pain score of ≥4/10 (16% in adults, 5% in adolescents). Those with notable back pain showed a significant (p < .0001) improvement two years after surgery. However, 24% of patients with no back pain at baseline showed a worsening of pain by 2 (out of 10) points or more two years postoperatively. There was no significant difference in the extent of improvement in older and younger patients (p = .22). CONCLUSION: In patients undergoing surgery for correction of AIS, back pain is correlated with age. In those with relevant back pain at baseline, surgery is associated with a statistically significant and clinically relevant reduction of pain 24 months later, in skeletally mature young adults and adolescents alike. LEVEL OF EVIDENCE: Level III.

Development of predictive models for all individual questions of SRS-22R after adult spinal deformity surgery: a step toward individualized medicine.

PURPOSE: Health-related quality of life (HRQL) instruments are essential in value-driven health care, but patients often have more specific, personal priorities when seeking surgical care. The Scoliosis Research Society-22R (SRS-22R), an HRQL instrument for spinal deformity, provides summary scores spanning several health domains, but these may be difficult for patients to utilize in planning their specific care goals. Our objective was to create preoperative predictive models for responses to individual SRS-22R questions at 1 and 2 years after adult spinal deformity (ASD) surgery to facilitate precision surgical care. METHODS: Two prospective observational cohorts were queried for ASD patients with SRS-22R data at baseline and 1 and 2 years after surgery. In total, 150 covariates were used in training machine learning models, including demographics, surgical data and perioperative complications. Validation was accomplished via an 80%/20% data split for training and testing, respectively. Goodness of fit was measured using area under receiver operating characteristic (AUROC) curves. RESULTS: In total, 561 patients met inclusion criteria. The AUROC ranged from 56.5 to 86.9%, reflecting successful fits for most questions. SRS-22R questions regarding pain, disability and social and labor function were the most accurately predicted. Models were less sensitive to questions regarding general satisfaction, depression/anxiety and appearance. CONCLUSIONS: To the best of our knowledge, this is the first study to explicitly model the prediction of individual answers to the SRS-22R questionnaire at 1 and 2 years after deformity surgery. The ability to predict individual question responses may prove useful in preoperative counseling in the age of individualized medicine. These slides can be retrieved under Electronic Supplementary Material.

Development of Deployable Predictive Models for Minimal Clinically Important Difference Achievement Across the Commonly Used Health-related Quality of Life Instruments in Adult Spinal Deformity Surgery.

STUDY DESIGN: Retrospective analysis of prospectively-collected, multicenter adult spinal deformity (ASD) databases. OBJECTIVE: To predict the likelihood of reaching minimum clinically important differences in patient-reported outcomes after ASD surgery. SUMMARY OF BACKGROUND DATA: ASD surgeries are costly procedures that do not always provide the desired benefit. In some series only 50% of patients achieve minimum clinically important differences in patient-reported outcomes (PROs). Predictive modeling may be useful in shared-decision making and surgical planning processes. The goal of this study was to model the probability of achieving minimum clinically important differences change in PROs at 1 and 2 years after surgery. METHODS: Two prospective observational ASD cohorts were queried. Patients with Scoliosis Research Society-22, Oswestry Disability Index , and Short Form-36 data at preoperative baseline and at 1 and 2 years after surgery were included. Seventy-five variables were used in the training of the models including demographics, baseline PROs, and modifiable surgical parameters. Eight predictive algorithms were trained at four-time horizons: preoperative or postoperative baseline to 1 year and preoperative or postoperative baseline to 2 years. External validation was accomplished via an 80%/20% random split. Five-fold cross validation within the training sample was performed. Precision was measured as the mean average error (MAE) and R values. RESULTS: Five hundred seventy patients were included in the analysis. Models with the lowest MAE were selected; R values ranged from 20% to 45% and MAE ranged from 8% to 15% depending upon the predicted outcome. Patients with worse preoperative baseline PROs achieved the greatest mean improvements. Surgeon and site were not important components of the models, explaining little variance in the predicted 1- and 2-year PROs. CONCLUSION: We present an accurate and consistent way of predicting the probability for achieving clinically relevant improvement after ASD surgery in the largest-to-date prospective operative multicenter cohort with 2-year follow-up. This study has significant clinical implications for shared decision making, surgical planning, and postoperative counseling. LEVEL OF EVIDENCE: 4.

What level of pain are patients happy to live with after surgery for lumbar degenerative disorders?

BACKGROUND CONTEXT: A new approach to the interpretation of treatment success comprises the reporting of the proportion of patients whose symptoms have reduced to an acceptable level, ie, who have reached a satisfactory state. PURPOSE: We sought to evaluate the acceptable level of pain in patients after surgery for painful degenerative lumbar disorders. DESIGN: This is a cross-sectional study of outcome data, 12 months postoperatively. PATIENT SAMPLE: The sample includes 6,943 patients registered in our in-house Spine Outcomes Registry, nested within the EUROSPINE "Spine Tango" registry, undergoing surgery for degenerative disorders of the lumbar spine (disc herniation [DH; N=1,608], spinal stenosis [SS; N=1,782], degenerative spondylolisthesis [DS; N=1,000], degenerative deformity [DegDef; N=612], and degenerative disc or segment disease [DegSeg; N=473], and 1,468 degenerative but no specific category). OUTCOME MEASURES: The Core Outcome Measures Index (COMI) was the outcome measure. The specific items used for this analysis were the two 0 to 10 graphic rating scales for back and leg pain and the symptom-specific well-being (SSWB) item "if you had to spend the rest of your life with the symptoms you have now, how would you feel about it?", with a 5-point response scale from "very satisfied" to "very dissatisfied." METHODS: The COMI was completed before and at 3, 12, and 24 months after surgery. Answers on the SSWB were dichotomized and used as the external criterion in receiver operating characteristics (ROC) analysis to derive the cutoff score for pain (the higher of back and leg pain) indicating being at least "somewhat satisfied" with the symptom state 12 months postoperatively. Sensitivity analyses were carried out for various subgroups (sex, age, pathology, comorbidity status, smoking status, preoperative pain level, previous surgery, type of health insurance, and time of follow-up [3 and 24 months]). The study was funded by the Schulthess Klinik Research Funds; there were no potential conflict of interest-associated biases for any of the authors. RESULTS: Of 6,943 patients, 6,248 (90%) returned a 12-month questionnaire, of which 47% reported being at least somewhat satisfied with their symptom state (52% [DH], 45% [SS], 53% [DS], 44% [DegDef], 45% [DegSeg], and 44% [others]). The areas under the curve for the ROCs were 0.89 to 0.91 for the different pathologies, indicating a good ability of the pain score to discriminate between being in a satisfactory state or not. The cutoff indicating a satisfactory symptom state was ≤2 points for DH (sensitivity: 76%; specificity: 88%) and ≤3 points for all other pathologies (sensitivity: 79%-84%; specificity 81%-85%). The sensitivity analyses revealed ≤3 points to be the most common cutoff for the various subgroups. CONCLUSIONS: Most spine interventions decrease pain but rarely do they totally eliminate it. Reporting of the percent of patients achieving a pain score equivalent to the "acceptable symptom state" may represent a more stringent target for denoting surgical success in the treatment of painful spinal disorders. For DH, this is ≤2, and for other degenerative pathologies it is ≤3.

Could less be more when assessing patient-rated outcome in spinal stenosis?

STUDY DESIGN: Longitudinal study of the measurement properties of a brief outcome instrument. OBJECTIVE: In patients undergoing surgery for lumbar spinal stenosis, we compared the responsiveness of the Core Outcome Measures Index (COMI) with that of the condition-specific Swiss Spinal Stenosis Measure (SSM), an instrument developed to assess patients with neurogenic claudication. SUMMARY OF BACKGROUND DATA: The COMI is a validated multidimensional questionnaire for assessing the key outcomes of importance to patients with back problems. Being brief, it is associated with minimal respondent burden and high completion rates. However, for a given pathology, intuitively it may be expected to be less responsive than a condition-specific instrument. METHODS: A total of 91 patients (73±8 yr; 53% males) completed the following questionnaires before surgery: COMI, SSM, Roland Morris Disability Questionnaire, back trouble "Feeling Thermometer," pain numeric rating scale, EuroQoL-visual analogue scale. Twelve months postoperatively, 78/91 (86%) completed all the questionnaires again; they also rated the "global treatment outcome" (GTO; rated 1-5) and SSM "satisfaction with treatment result" (SSM-sat; rated 1-4), which were used as external criteria of treatment success. RESULTS: Scores for the external criteria of success (GTO/SSM-sat) correlated with the change scores (baseline to 12 mo) in COMI (r=0.57) and SSM (r=0.54) to a similar extent. Using receiver operating characteristics, with GTO or SSM-sat dichotomized as external criterion, the area under the curve was similar for the COMI change score (0.86-0.90) and the SSM (sub)scales (0.80-0.90). CONCLUSION: With either SSM-sat or GTO serving as the external criterion, COMI was as responsive as the SSM. The COMI is well able to detect important change in lumbar spinal stenosis and has the added benefit of reducing the response burden for the patient and facilitating outcome comparisons with other spinal pathologies. LEVEL OF EVIDENCE: 2.

Lumbar facet joint effusion on MRI as a sign of unstable degenerative spondylolisthesis: should it influence the treatment decision?

STUDY DESIGN: Retrospective study. OBJECTIVE: To examine whether the outcomes of decompression alone (D) or decompression with fusion (D&F) differed depending on the presence or absence of the facet effusion sign in degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: There is ongoing discussion as to whether D&F is superior to D in the surgical treatment of patients with lumbar degenerative spondylolisthesis (LDS) and symptoms of spinal or radicular claudication. Previous studies have shown that a positive facet joint effusion sign on magnetic resonance imaging correlates with the spontaneous reduction of slip when comparing upright and supine postures and might represent a sign of instability, guiding treatment decisions. PATIENTS AND METHODS: One hundred sixty patients [age 69 (SD 10) y; 119 women, 41 men] with a diagnosis of LDS were identified retrospectively from our Spine Center Registry (linked to the Eurospine, Spine Society of Europe Spine Tango Registry). They were categorized based on the presence/absence of the facet effusion sign and the type of treatment received. Forty-four patients had effusion and underwent D; 76 effusion and D&F; 19 no effusion and D; and 21 no effusion and D&F. Before surgery and 3, 12, and 24 months after surgery, patients completed the multidimensional Core Outcome Measures Index questionnaire. At follow-up, they rated the global treatment outcomes (1-5 scale). Multiple regression analyses evaluated the factors influencing the outcomes. RESULTS: When age and sex was controlled for, there was no significant difference in outcomes dependent on the presence of the facet effusion sign and/or the treatment received (D vs. D&F). CONCLUSIONS: Although mindful of the limitations of this retrospective study, we conclude that the effusion sign alone does not seem to be an indication for adding fusion to decompression in the treatment of LDS. Hence, the presence of the facet effusion sign should not, in itself, deter the surgeon from performing decompression alone. However, the phenomenon should be investigated in larger samples of patients, ideally within a randomized trial.

The influence of cervical plate fixation with either autologous bone or cage insertion on radiographic and patient-rated outcomes after two-level anterior cervical discectomy and fusion.

PURPOSE: We aimed to identify technique-related factors influencing radiographic and patient-rated outcomes after two-level anterior cervical discectomy with fusion (ACDF) using either cage or autologous bone, with or without anterior plate fixation (APF). METHODS: This single center study was nested within the Eurospine Spine Tango data acquisition system. INCLUSION CRITERIA: consecutive two-level ACDF patients (2004-2012) presenting with signs of degenerative cervical radiculopathy or myelopathy. Before and 12 month postoperatively, patients completed the multidimensional Core Outcome Measures Index (COMI); at 12 months postoperatively they also rated the global treatment outcome (GTO) and their satisfaction with care. Cervical lordosis and segmental height were assessed radiographically preoperatively, immediately postoperatively, and at the last follow-up (LFU) (18.2 ± 13.3 months). RESULTS: One hundred and forty-four consecutive patients (113 with APF) were included. The use of APF versus stand-alone methods was associated with significantly increased segmental height (by 2.6 ± 2.6 versus 1.5 ± 2.4 mm, p = 0.04) and preservation of lordosis (by 2.7 ± 4.4° versus -1.7 ± 5°, p < 0.0001) at LFU, with comparable clinical outcome (COMI score reduction ≥3.1-point). Multiple regression controlling for potential confounders revealed that APF (p = 0.0004) and cage (p = 0.001) were associated with greater segmental height at LFU; APF was associated with a greater lordosis angle at LFU (p < 0.0001). Greater increase in segmental height at LFU (p = 0.02) was associated with a better GTO. CONCLUSIONS: Adding APF was associated with greater segmental height and preservation of lordosis in two-level ACDF, especially using bone autograft, but also for cage. Clinical outcome was comparable for all groups. Though the surgical technique per se did not determine clinical outcome, patients achieving a greater segmental height difference showed a significantly better GTO.

A comparison of patient and surgeon preoperative expectations of spinal surgery.

STUDY DESIGN: Cross-sectional study of agreement between patients' and surgeons' expectations of the outcome of spinal surgery. OBJECTIVE: Patients' satisfaction after spinal surgery depends, in part, on whether their expectations of surgery are fulfilled. Whether the patient always fully understands the key messages conveyed by the surgeon, to formulate realistic expectations, is not known. This study evaluates the level of agreement in expectations declared preoperatively by the patient and the surgeon. SUMMARY OF BACKGROUND DATA: Previous studies have investigated the importance of realistic expectations for the patients' satisfaction with surgical treatments, but there is still a need for a more detailed analysis in the field of spinal surgery. METHODS: The study included 225 German-speaking patients (92 men and 133 women; mean ± SD [range] age, 62 ± 15 [15-90] yr) and their treating spinal surgeons (N = 7). Following the preoperative informed consent consultation, the patient and the surgeon independently completed a questionnaire about baseline neurological status and realistic expectations regarding various patient-orientated outcomes (axial pain (back/neck), radiating pain (leg/arm), pain medication usage, sensory and motor function, and the ability to work, do household activities, and play sports). Concordance was given by percent agreement and κ coefficients. RESULTS: Agreement between the patient and the surgeon about the existence of spine-related neurological deficits occurred in 75% (sensory) and 61% (motor) cases. The patient but not the surgeon reported a sensory deficit in 20% cases and motor deficit in 35% cases; for 4% to 5% cases, the physician reported such a deficit that the patient was seemingly unaware of. The patients consistently had higher expectations than the surgeons, especially for back or neck pain and function (work, household activities, and sports); weighted κ values for agreement were low, ranging from 0.097 to 0.222. CONCLUSION: The findings demonstrate wide discrepancies between the patient and the surgeon regarding the expected result of surgery. They highlight the need for clearer explanations of the association between the spinal problem and neurological deficits and the improvement that can be expected in pain and function after surgery. Systematic, routine evaluation of outcomes should assist in deriving the information necessary to document the improvement achieved and to formulate realistic expectations of surgery.

Lumbar facet joint effusion in MRI: a sign of instability in degenerative spondylolisthesis?

PURPOSE: The term "segmental instability" of the lumbar spine is not clearly defined, especially as it relates to degenerative spondylolisthesis (DS) and rotational translation (RT). We investigated whether facet joint effusion on conventional supine MRI indicated increased abnormal motion in DS and RT. METHODS: 160 patients (119 female, 41 male, mean age 68.8 years, range 38.8-89.3 years) who had undergone decompression only or decompression with instrumented fusion for degenerative spondylolisthesis with different degrees of narrowing of the spinal canal were identified retrospectively from our spine surgery database. All had preoperative upright X-rays in AP and lateral views as well as supine MRI. The imaging studies were assessed for the following parameters: percent of slippage, absolute value of facet joint effusion, facet angles, degree of facet degeneration and spinal canal central narrowing, disc height, presence of facet cysts and the presence of rotational translation in the AP X-ray. RESULTS: 40/160 patients showed no facet joint effusion, and in these the difference in the values for the % slip on upright X-ray and % slip on supine MRI was ≤3%. A further 12 patients also showed a difference ≤3%, but had some fluid in the joints (0.44 ± 0.38 mm). In 108 patients, the difference in the % slip measured on X-ray and on MRI was >3% (mean 10.6%, range 4-29%) and was associated with a mean facet effusion size of 2.15 ± 0.85 mm. The extent of effusion correlated significantly with the relative slippage difference between standing and supine positions (r = 0.64, p < 0.001), and the extent of the left/right difference in effusion was associated with the presence of rotational translation (RT 1.31 ± 0.8 mm vs. no-RT 0.23 ± 0.17 mm, p < 0.0001). CONCLUSIONS: Facet joint effusion is clearly correlated with spontaneous reduction of the extent of slippage in the supine position compared to the upright position. Also, the greater the difference in right and left facet effusion, the higher the likelihood of having a RT. Future studies should assess whether analysis of facet joint effusion measured on routine MRI can help in decision-making regarding the optimal surgical treatment to be applied (decompression alone or combined with fusion).

Prospective study of the effect of pedicle screw placement on development of the immature vertebra in an in vivo porcine model.

INTRODUCTION: There is increasing awareness of the need for pedicle screw constructs in the treatment of spinal deformities in very young children. However, the long-term effects of pedicle screws on the immature spine are still unclear. We used a porcine model to analyze the morphological changes of the spinal canal and vertebral body in response to the placement of pedicle screws. METHODS: 13 newborn pigs were operated on. Each pig received a single pedicle screw at the L2 level. After a tenfold increase in body weight (7 months later), the symmetry of the spinal canal and vertebral body was measured on CT scans of the investigational (L2) and control (L3) levels in terms of the angulations of the instrumented and non-instrumented halves of the vertebral body and spinal canal. RESULTS: After 7 months, the normalised vertebral body angle had reduced on the non-screw side and increased on the screw side, indicating asymmetry in vertebral body growth in the axial plane. The difference was significant (p = 0.009). However, there was no significant difference between the screw and non-screw sides for the spinal canal angles at the L2 level at either the intraoperative or 7-month follow-up assessment (each p > 0.05). CONCLUSIONS: Pedicle screws in the immature porcine spine have a significant effect on the development of the vertebral body. However, in the present study, no corresponding alteration of the morphology of the spinal canal was observed. Our results provide further support for the existing arguments in favour of pedicle screws when weighing up the many factors to be considered in creating a treatment plan for early onset scoliosis.

A comparison of outcomes of cervical disc arthroplasty and fusion in everyday clinical practice: surgical and methodological aspects.

Randomised controlled trials (RCTs) of cervical disc arthroplasty vs fusion generally show slightly more favourable results for arthroplasty. However, RCTs in surgery often have limited external validity, since they involve a select group of patients who fit very rigid admission criteria and who are prepared to subject themselves to randomisation. The aim of this study was to examine whether the findings of RCTs are verified by observational data recorded in our Spine Center in association with the Spine Society of Europe Spine Tango surgical registry. Patients undergoing fusion/stabilisation or disc arthroplasty for degenerative cervical spinal disease were selected for inclusion. They completed a questionnaire pre-operatively and at 12 and 24 months follow-up (FU). The questionnaire comprised the multidimensional Core Outcome Measures Index (COMI; 0-10 scale) and, at FU, questions on global outcome and satisfaction with treatment (5-point scales, dichotomised to "good" and "poor"), re-operation and patient-rated complications. The surgeon completed a Spine Tango Surgery form. The outcome data from 266 (208 fusion, 58 arthroplasty) out of 284 eligible patients who had reached 12 months FU, and 169 (139 fusion, 30 arthroplasty) out of 178 who had reached 24 months FU, were included. Patients with cervical disc arthroplasty were younger [46 (SD 8) years vs 56 (SD 11) years for fusion; P < 0.05], had less comorbidity (P < 0.05), more often had only mono-segmental pathology (69% arthroplasty, 47% fusion) and only one type of degenerative pathology (69% arthroplasty, 46% fusion). Surgical complication rates were similar in each group (arthroplasty, 1.5%; fusion, 2.6%). The reduction in the COMI score was significantly greater in the arthroplasty group (at 12 months, 4.8 (SD 3.0) vs 3.7 (SD 2.9) points for fusion, and at 24 months 5.1 (SD 2.8) vs 3.8 (SD 2.9) points; each P < 0.05). In the arthroplasty group, a "good" global outcome was recorded in 90% patients (at 12 months) and 93% (at 24 months); in the fusion group the figures were 80 and 82%, respectively (group differences at each timepoint, P > 0.09). Satisfaction with treatment was similar in both groups (89-93%), at each timepoint. In multiple regression analysis, treatment group was of borderline significance as a unique predictor of the change in COMI at FU (P = 0.059 at 12 months, P = 0.055 at 24 months) in a model in which known confounders (age, comorbidity, number of affected levels) were controlled for. Being in the arthroplasty group was associated with an approximately 1-point greater reduction in the COMI score at FU. The results of this observational study appear to support those of the RCTs and suggest that, in patients with degenerative pathology of the cervical spine, disc arthroplasty is associated with a slightly better outcome than fusion. However, given the small size of the difference, its clinical relevance is questionable, especially in view of the a priori more favourable outcome expected in the arthroplasty group due to the more rigorous selection of patients.

The influence of preoperative back pain on the outcome of lumbar decompression surgery.

STUDY DESIGN: Prospective study with 12-month follow-up. OBJECTIVE: To examine how the relative severity of low back pain (LBP) to leg/buttock pain (LP) influences the outcome of decompression surgery for spinal stenosis. SUMMARY OF BACKGROUND DATA: Decompression surgery is a common treatment for lumbar spinal canal stenosis, with generally good outcome. However, concomitant LBP at presentation can make it difficult to decide whether decompression alone will result in a good overall outcome. METHODS: The Spine Society of Europe Spine Tango system was used to acquire the data from 221 patients. Inclusion criteria were lumbar degenerative spinal stenosis, first-time surgery, maximum 3 affected levels, and decompression as the only procedure. Before and 12 months after surgery, patients completed the multidimensional Core Outcome Measures Index (COMI; includes 0-10 LP and LBP scales); at 12 months, global outcome was rated on a Likert-scale and dichotomized into "good" and "poor" groups. RESULTS: There was a low but significant positive correlation between baseline LP-minus-LBP scores and both improvement in the multidimensional COMI score after 12 months (r = 0.21, P = 0.003) and the score on the 12-month global outcome scale (r = 0.19, P = 0.007). In the good outcome group, mean baseline LP was 2.3 (+/-3.7) points higher than LBP; in the poor group, the corresponding value was 0.8 (+/-3.4) (P = 0.01 between groups). In multivariate regression analyses (controlling for age, gender, comorbidity), baseline LBP intensity was the most significant predictor of the 12-month COMI score, and preoperative LP-minus-LBP score of the global outcome (each P < 0.05). CONCLUSION: Overall, greater back pain relative to LP at baseline was associated with a significantly worse outcome after decompression. This finding seems intuitive, but has rarely been quantified in the many predictor studies conducted to date. Consideration of relative LBP and LP scores may assist in clinical decision-making and in establishing realistic patient expectations.