Development of a machine-learning based model for predicting multidimensional outcome after surgery for degenerative disorders of the spine.

BACKGROUND: It is clear that individual outcomes of spine surgery can be quite heterogeneous. When consenting a patient for surgery, it is important to be able to offer an individualized prediction regarding the likely outcome. This study used a comprehensive set of data collected over 12 years in an in-house registry to develop a parsimonious model to predict the multidimensional outcome of patients undergoing surgery for degenerative pathologies of the thoracic, lumbar or cervical spine. METHODS: Data from 8374 patients (mean age 63.9 (14.9-96.3) y, 53.4% female) were used to develop a model to predict the 12-month scores for the Core Outcome Measures Index (COMI) and its subdomain scores. The data were split 80:20 into a training and test set. The top predictors were selected by applying recursive feature elimination based on LASSO cross validation models. Based on the 111 top predictors (contained within 20 variables), Ridge cross validation models were trained, validated, and tested for each of 9 outcome domains, for patients with either "Back" (thoracic/lumbar spine) or "Neck" (cervical spine) problems (total 18 models). RESULTS: Among the strongest outcome predictors in most models were: preoperative scores for almost all COMI items (especially axial pain (back or neck) and peripheral pain (leg/buttock or arm/shoulder)), catastrophizing, fear avoidance beliefs, comorbidity, age, BMI, nationality, previous spine surgery, type and spinal level of intervention, number of affected levels, and surgeon seniority. The R2 of the models on the validation/test sets averaged 0.16/0.13. A preliminary online tool was programmed to present the predicted outcomes for individual patients, based on their presenting characteristics. https://linkup.kws.ch/prognostictool . CONCLUSION: The models provided estimates to enable a bespoke prediction of the outcome of surgery for individual patients with varying degenerative pathologies and baseline characteristics. The models form the basis of a simple, freely-available online prognostic tool developed to improve access to and usability of prognostic information in clinical practice. It is hoped that, following confirmation of its validity and practical utility, the tool will ultimately serve to facilitate decision-making and the management of patients' expectations.

Development of a mapping function ("crosswalk") for the conversion of scores between the Oswestry Disability Index (ODI) and the Core Outcome Measures Index (COMI).

INTRODUCTION: The Oswestry Disability Index (ODI) and the Core Outcome Measures Index (COMI) are two commonly used self-rating outcome instruments in patients with lumbar spinal disorders. No formal crosswalk between them exists that would otherwise allow the scores of one to be interpreted in terms of the other. We aimed to create such a mapping function. METHODS: We performed a secondary analysis of ODI and COMI data previously collected from 3324 patients (57 ± 17y; 60.3% female) at baseline and 1y after surgical or conservative treatment. Correlations between scores and Cohen's kappa for agreement (κ) regarding achievement of the minimal clinically important change (MCIC) score on each instrument (ODI, 12.8 points; COMI, 2.2 points) were calculated, and regression models were built. The latter were tested for accuracy in an independent set of registry data from 634 patients (60 ± 15y; 56.8% female). RESULTS: All pairs of measures were significantly positively correlated (baseline, 0.73; 1y follow-up (FU), 0.84; change-scores, 0.73). MCIC for COMI was achieved in 53.9% patients and for ODI, in 52.4%, with 78% agreement on an individual basis (κ = 0.56). Standard errors for the regression slopes and intercepts were low, indicating excellent prediction at the group level, but root mean square residuals (reflecting individual error) were relatively high. ODI was predicted as COMI × 7.13-4.20 (at baseline), COMI × 6.34 + 2.67 (at FU) and COMI × 5.18 + 1.92 (for change-score); COMI was predicted as ODI × 0.075 + 3.64 (baseline), ODI × 0.113 + 0.96 (FU), and ODI × 0.102 + 1.10 (change-score). ICCs were 0.63-0.87 for derived versus actual scores. CONCLUSION: Predictions at the group level were very good and met standards justifying the pooling of data. However, we caution against using individual values for treatment decisions, e.g. attempting to monitor patients over time, first with one instrument and then with the other, due to the lower statistical precision at the individual level. The ability to convert scores via the developed mapping function should open up more centres/registries for collaboration and facilitate the combining of data in meta-analyses.

Patient-rated outcome after atlantoaxial (C1-C2) fusion: more than a decade of evaluation of 2-year outcomes in 126 patients.

INTRODUCTION: Various surgical techniques have been introduced for atlantoaxial (C1-C2) fusion, the most common being Magerl's (transarticular) or the Harms/Goel screw fixation. Common indications include degenerative osteoarthritis (OA), trauma or rheumatoid arthritis (RA). Only few, small studies have evaluated patient-reported outcomes after C1-C2 fusion. We investigated 2-year outcomes in a large series of consecutive patients undergoing isolated C1-C2 fusion. METHODS: We analysed prospectively collected data (2005-2016) from our Spine outcomes database, collected within the framework of EUROSPINE's Spine Tango Registry. It included 126 patients (34 (27%) men, 92 (73%) women; mean (SD) age 67 ± 19 y) who had undergone first-time isolated C1-C2 fusion (61% Magerl, 39% Harms(-Goel)) at least 2 years ago for OA (83 (66%)), RA (20 (16%)), fracture (15 (12%)) or other (8 (6%)). Patients completed the multidimensional Core Outcome Measures Index (COMI; 0-10) and various single item outcomes. RESULTS: Questionnaires were returned by 118/126 (94%) patients, 2 years post-operative. Mean COMI scores showed a significant reduction from baseline: 6.9 ± 2.4 to 2.7 ± 2.5 (p < 0.0001). Overall, 75% patients achieved the MCIC of ≥ 2.2 points reduction in COMI and 88% reported a good global outcome. 91% patients were satisfied/very satisfied with their care. Self-reported complications were declared by 16% patients and further surgery at the same segment, by 2.5%. CONCLUSION: In this large series with almost complete follow-up, C1-C2 fusion showed extremely good results. Despite the complexity of the intervention, outcomes surpassed those typically reported for simple procedures such as ACDF and lumbar discectomy, suggesting reservations about the procedure should perhaps be reviewed.

Non-medical factors significantly influence the length of hospital stay after surgery for degenerative spine disorders.

BACKGROUND: Unnecessarily long hospital stays are costly and inefficient. Studies have shown that the length of hospital stay (LOS) for spine surgical procedures is influenced by various disease-related or medical factors, but few have examined the role of socio-demographic/socio-economic (SDE) factors. METHODS: This was a retrospective analysis of data from 10,770 patients (5056 men, 5714 women; 62 ± 15 years) with degenerative spinal disorders, collected prospectively in an in-house database within the framework of EUROSPINE's Spine Tango Registry. Surgeons completed the Tango surgery form (clinical history, demographics, surgical measures, complications), and patients, a baseline Core Outcome Measures Index. Stepwise linear regression analyses examined SDE predictors of LOS, controlling for potential medical/biological factors. RESULTS: The mean LOS was 7.9 ± 5.2 days. The final model accounted for 42% of variance in LOS, with SDE variables explaining 13% variance and medical/surgical predictors, 29%. In the final model, the SDE factors age and being female were significant independent predictors of LOS, whereas others were either non-significant (insurance status, being of Swiss nationality, being a smoker) or reached only borderline significance (p < 0.1) (BMI). Controlling for all other SDE and medical/surgical confounders, being female was associated with 1.11-day longer LOS (95% CI 0.96-1.27; p < 0.0001). CONCLUSIONS: Patients of advanced age and female gender are at increased risk of longer hospital stay after surgery for degenerative spinal disorders. Further studies should seek to understand the reasoning behind the gender disparity, in order to minimise potentially unnecessary costs of prolonged LOS. Targeted preoperative discharge planning may improve the utilisation of hospital resources. These slides can be retrieved under Electronic Supplementary Material.

Can the Charlson Comorbidity Index be used to predict the ASA grade in patients undergoing spine surgery?

BACKGROUND: The American Society of Anaesthesiologists' Physical Status Score (ASA) is a key variable in predictor models of surgical outcome and "appropriate use criteria". However, at the time when such tools are being used in decision-making, the ASA rating is typically unknown. We evaluated whether the ASA class could be predicted statistically from Charlson Comorbidy Index (CCI) scores and simple demographic variables. METHODS: Using established algorithms, the CCI was calculated from the ICD-10 comorbidity codes of 11'523 spine surgery patients (62.3 ± 14.6y) who also had anaesthetist-assigned ASA scores. These were randomly split into training (N = 8078) and test (N = 3445) samples. A logistic regression model was built based on the training sample and used to predict ASA scores for the test sample and for temporal (N = 341) and external validation (N = 171) samples. RESULTS: In a simple model with just CCI predicting ASA, receiver operating characteristics (ROC) analysis revealed a cut-off of CCI ≥ 1 discriminated best between being ASA ≥ 3 versus < 3 (area under the curve (AUC), 0.70 ± 0.01, 95%CI,0.82-0.84). Multiple logistic regression analyses including age, sex, smoking, and BMI in addition to CCI gave better predictions of ASA (Nagelkerke's pseudo-R2 for predicting ASA class 1 to 4, 46.6%; for predicting ASA ≥ 3 vs. < 3, 37.5%). AUCs for discriminating ASA ≥ 3 versus < 3 from multiple logistic regression were 0.83 ± 0.01 (95%CI, 0.82-0.84) for the training sample and 0.82 ± 0.01 (95%CI, 0.81-0.84), 0.85 ± 0.02 (95%CI, 0.80-0.89), and 0.77 ± 0.04 (95%CI,0.69-0.84) for the test, temporal and external validation samples, respectively. Calibration was adequate in all validation samples. CONCLUSIONS: It was possible to predict ASA from CCI. In a simple model, CCI ≥ 1 best distinguished between ASA ≥ 3 and < 3. For a more precise prediction, regression algorithms were created based on CCI and simple demographic variables obtainable from patient interview. The availability of such algorithms may widen the utility of decision aids that rely on the ASA, where the latter is not readily available.

Does neck pain as chief complaint influence the outcome of cervical total disc replacement?

PURPOSE: We investigated whether outcomes after cervical total disc replacement (cTDR) are influenced by preoperative neck pain as the chief complaint. METHODS: This was a retrospective study using data in our local spine surgery outcomes database, linked to EUROSPINE Spine Tango Registry. Patients completed questionnaires at baseline enquiring about the "chief complaint" [neck pain (NP), arm/shoulder pain (AP) or neurological deficits (ND)] and including the Core Outcome Measures Index (COMI); these were completed again at 24 months postoperatively, along with a rating of "global treatment outcome" (on a five-point scale, later dichotomized as "good" or "poor"). Differences in outcomes between the groups were examined using ANOVA. Multivariable regression analysis examined the effect of the chief pain location on 24-month outcomes, controlling for age, gender, comorbidity, baseline pain and COMI scores. RESULTS: One hundred and fifty-nine consecutive patients were included, with a chief complaint of NP in 31%, AP in 38% and ND in 31%. The chief complaint groups did not differ in relation to their baseline COMI scores or their reductions in score from before surgery to 24 months after surgery (reduction: NP group, 4.4 ± 2.9 points; AP group, 4.7 ± 2.7; ND group, 4.3 ± 2.9; p = 0.78). Similarly, the percentage of patients reporting a "good global treatment outcome" at 24 months postoperatively did not differ between the groups (NP, 79%; AP, 77%; ND, 85%; p = 0.64). The findings were consistent when controlling for possible confounders in multiple regression. CONCLUSIONS: Having neck pain as opposed to arm pain or neurological deficits as preoperative chief complaint had no significant impact on clinical outcome after cTDR. These slides can be retrieved under Electronic Supplementary Material.

What level of symptoms are patients with adult spinal deformity prepared to live with? A cross-sectional analysis of the 12-month follow-up data from 1043 patients.

INTRODUCTION: Previous studies suggest that a meaningful and easily understood measure of treatment outcome may be the proportion of patients who are in a "patient acceptable symptom state" (PASS). We sought to quantify the score equivalent to PASS for different outcome instruments, in patients with adult spinal deformity (ASD). METHODS: We analysed the following 12-month questionnaire data from the European Spine Study Group (ESSG): Oswestry Disability Index (ODI; 0-100); Numeric Rating Scales (NRS; 0-10) for back/leg pain; Scoliosis Research Society (SRS) questionnaire; and an item "if you had to spend the rest of your life with the symptoms you have now, how would you feel about it?" (5-point scale, dichotomised with top 2 responses "somewhat satisfied/very satisfied" being considered PASS+, everything else PASS-). Receiver operating characteristics (ROC) analyses indicated the cut-off scores equivalent to PASS+. RESULTS: Out of 1043 patients (599 operative, 444 non-operative; 51 ± 19 years; 84% women), 42% reported being PASS+ at 12 months' follow-up. The ROC areas under the curve were 0.71-0.84 (highest for SRS subscore), suggesting the questionnaire scores discriminated well between PASS+ and PASS-. The scores corresponding to PASS+ were > 3.5 for the SRS subscore (> 3.3-3.8 for SRS subdomains); ≤ 18 for ODI; and ≤ 3 for NRS pain. There were slight differences in cut-offs for subgroups of age, treatment type, aetiology, baseline symptoms, and sex. CONCLUSION: Most interventions for ASD improve patients' complaints but do not totally eliminate them. Reporting the percentage achieving a score equivalent to an "acceptable state" may represent a more stringent and discerning target for denoting treatment success in ASD. These slides can be retrieved under Electronic Supplementary Material.

Dural sac cross-sectional area and morphological grade show significant associations with patient-rated outcome of surgery for lumbar central spinal stenosis.

PURPOSE: Lumbar central spinal stenosis (LSS) is one of the most common reasons for spine surgery in the elderly patient. Magnetic resonance imaging (MRI) represents the gold standard for the assessment of LSS and can be used to obtain quantitative measures of the dural sac cross-sectional area (DCSA) or qualitative measures (morphological grades A-D) of the rootlet/cerebrospinal fluid ratio. This study investigated the intercorrelation between these two MRI evaluation methods and explored their respective relationships with the patient baseline clinical status and outcome 12 months after surgery. METHODS: This was a retrospective analysis of prospectively collected data from 157 patients (88 male, 69 female; age 72 ± 7 years) who were undergoing first-time surgery for LSS. Patients with foraminal or isolated lateral stenosis were excluded. The Core Outcome Measures Index (COMI) was completed before and 12 months after surgery. Preoperative T2 axial MRIs were blinded and independently evaluated for DCSA and morphological grade. Spearman rank correlation coefficients described the relationship between the two MRI measures of stenosis severity and between each of these and the COMI baseline and change-scores (pre to 12 months' postop). Multiple logistic regression analysis (controlling for baseline COMI, age, gender, number of operated levels, health insurance status) was used to analyse the influence of stenosis severity on the achievement of the minimum clinically important change (MCIC) score for COMI and on global treatment outcome (GTO). RESULTS: There was a correlation of ρ = -0.69 (p < 0.001) between DCSA and morphological grade. There was no significant correlation between COMI baseline scores and either DCSA or morphological grades (p > 0.85). However, logistic regression revealed significant (p < 0.05) associations between stenosis ratings and 12-month outcome, whereby patients with more severe stenosis (as measured using either of the methods) benefited more from the surgery. Patients with a DCSA <75 mm2 or morphological grade D had a 4-13-fold greater odds of achieving the MCIC for COMI or a "good" GTO, compared with patients in the least severe categories of stenosis. CONCLUSIONS: Postoperative outcome was clearly related to the degree of preoperative radiological LSS. The two MRI methods appeared to deliver similar information, as given by the relatively strong correlation between them and their comparable performance in relation to baseline and 12-month outcomes. However, the qualitative morphological grading can be performed in an instant, without measurement tools, and does not deliver less clinically useful information than the more complex and time-consuming measures; as such, it may represent the preferred method in the clinical routine for assessing the extent of radiological stenosis and the likelihood of a positive outcome after decompression.

A novel use of the Spine Tango registry to evaluate selection bias in patient recruitment into clinical studies: an analysis of patients participating in the Lumbar Spinal Stenosis Outcome Study (LSOS).

PURPOSE: Patients enrolled in clinical studies typically represent a sub-set of all who are eligible, and selection bias may compromise the generalizability of the findings. Using Registry data, we evaluated whether surgical patients recruited by one of the referring centres into the Lumbar Spinal Stenosis Outcome Study (LSOS; a large-scale, multicentre prospective observational study to determine the probability of clinical benefit after surgery) differed in any significant way from those who were eligible but not enrolled. METHODS: Data were extracted for all patients with lumbar spinal stenosis registered in our in-house database (interfaced to Eurospine's Spine Tango Registry) from 2011 to 2013. Patient records and imaging were evaluated in relation to the admission criteria for LSOS to identify those who would have been eligible for participation but were not enrolled (non-LSOS). The Tango surgery data and Core Outcome Measures Index (COMI) data at baseline and 3 and 12 months after surgery were analysed to evaluate the factors associated with LSOS enrolment or not. RESULTS: 514 potentially eligible patients were identified, of which 94 (18%) were enrolled into LSOS (range 2-48% for the 6 spine surgeons involved in recruiting patients) and 420 (82%) were not; the vast majority of the latter were due to non-referral to the study by the surgeon, with only 5% actually refusing participation. There was no significant difference in gender, age, BMI, smoking status, or ASA score between the two groups (p ≥ 0.18). Baseline COMI was significantly (p = 0.002) worse in the non-LSOS group (7.4 ± 1.9) than the LSOS group (6.7 ± 1.9). There were no significant group differences in any Tango surgery parameters (additional spine patholothegies, operation time, blood loss, complications, etc.) although significantly more patients in the non-LSOS group had a fusion procedure (38 vs 18% in LSOS; p = 0.0004). Postoperatively, neither the COMI nor its subdomain scores differed significantly between the groups (p > 0.05). Multiple logistic regression revealed that worse baseline COMI (p = 0.021), surgeon (p = 0.003), and having fusion (p = 0.014) predicted non-enrolment in LSOS. CONCLUSION: A high proportion of eligible patients were not enrolled in the study. Non-enrolment was explained in part by the specific surgeon, worse baseline COMI status, and having a fusion. The findings may reflect a tendency of the referring surgeon not to overburden more disabled patients and those undergoing more extensive surgery with the commitments of a study. Beyond these factors, non-enrolment appeared to be somewhat arbitrary, and was likely related to surgeon forgetfulness, time constraints, and administrative errors. Researchers should be aware of potential selection bias in their clinical studies, measure it (where possible) and discuss its implications for the interpretation of the study's findings.

Adult degenerative scoliosis: comparison of patient-rated outcome after three different surgical treatments.

PURPOSE: Few studies have examined the effectiveness of surgical treatment for adult degenerative scoliosis (ADS) using validated patient-orientated outcome instruments. This study reports patient outcomes in a large, consecutive series of patients being treated for ADS by simple decompression (D), short fusion (SF), or long fusion (LF). METHODS: Our local spine surgery database (part of the Eurospine Spine Tango Registry) was used to acquire the data from patients with ADS undergoing D, SF or LF. Preoperatively and at 12 and 24 months follow-up (FU), patients completed the multidimensional Core Outcome Measures Index (COMI; 0-10); at FU, satisfaction and global outcome were rated on a five-point Likert scale and dichotomised as "good" and "poor", and patient-rated complications were recorded. RESULTS: 173 patients took part (81 D, 53 SF, 39 LF). Compared with the two fusion groups, the D group was significantly older, had more comorbidity, and had more leg pain than back pain (each p < 0.05). There were significant differences among the groups for operation duration, blood loss and general complications (each p < 0.05), in each case with the LF group showing the greatest values and the D group the lowest values. However, patient-rated complications were not significantly different between the groups (p > 0.89). Further surgery within the 2-year follow-up was required in 7 % of the D group, 15 % in SF and 28 % in LF. All groups benefited significantly from surgery with no significant differences (p > 0.05) between them: improvement in COMI after 24 months was 2.9 ± 2.8 points for D, 3.1 ± 3.3 points for SF and 3.2 ± 3.1 points for LF; a "good global outcome" was recorded for 69, 74 and 76 % patients, respectively. CONCLUSIONS: Despite the complexity of the disease, patient-orientated outcomes after surgery for ADS were similar to those previously reported using the same outcome instruments in patients with lumbar stenosis and degenerative spondylolisthesis. The use of D, SF and LF for ADS yielded similarly good results from the patient's perspective. This most likely reflects careful and appropriate patient selection. Further analyses are warranted to identify baseline variables predicting the 26-31 % cases in each group with a poor outcome.

[Congenital malformations of the growing spine : When should treatment be conservative and when should it be surgical?]. / Kongenitale Fehlbildungen der Wirbelsäule im Wachstum : Wann konservativ behandeln, wann operativ?

Congenital malformations of the spine are caused by genetic and teratogenic factors. By means of asymmetrical longitudinal growth of the spine they can lead to deformity, most commonly to scoliosis. The malformations can be classified as failure of formation, failure of segmentation and mixed-type malformations. The extent of the deformity and its progression are determined by the remaining growth potential and the location and type of malformation. Up to one third of such deformities are associated with some sort of cardiac or urogenital malformation. The treatment concept is typically determined on an individual basis. Mild deformities often remain undetected. Conservative treatment using a brace has no substantial effect on the primary curve but might be helpful in the treatment of long sweeping, flexible, secondary curves. If rapid progression is documented or expected, surgical intervention as early as possible is warranted to prevent secondary structural changes. The surgical treatment should be focused on and limited to the site of malformation. The aim of surgery is the correction of the deformity at the site of asymmetrical growth. This can be achieved either by resection of a hemivertebra or by performing a vertebral column resection or other type of osteotomy. If notable compensatory, secondary curves are present, these can be corrected with growing rod constructs. The aim of all types of treatment is the correction of existing deformity or the prevention of its progression, in order to ensure balanced growth of the healthy regions of the spine. The present paper discusses the conservative and surgical treatment modalities available to achieve these aims.

Posterior vertebral column resection in early onset spinal deformities.

PURPOSE: Early onset spinal deformities (EOSD) can be life-threatening in very young children. In the growing spine, surgical intervention is often unavoidable and should be carried out as soon as possible. A deformed section of the spine not only affects the development of the remaining healthy spine, but also that of the chest wall (which influences pulmonary function), the extremities and body balance. Posterior vertebral column resection (PVCR) represents an effective surgical solution to address such problems. However, reports in the literature concerning PVCR are mostly limited to its use in adolescents or adults. The purpose of this study was to illustrate our experience with PVCR in EOSD and to describe the surgical technique with respect to the unique anatomy of young children. MATERIALS AND METHODS: Four children [mean age 3.7 (range 2.5-5.2) years] with severe spinal deformity underwent PVCR through a single approach. Multimodal intraoperative monitoring was used in all cases. Surgery included one stage posterior circumferential resection of one vertebral body along with the adjoining intervertebral discs and removal of all posterior elements. A transpedicular screw-rod system was used for correction and stabilisation. Fusion was strictly limited to the resection site, allowing for later conversion into a growing rod construct at the remaining spine, if necessary. Relevant data were extracted retrospectively from patient charts and long spine radiographs. RESULTS: The mean operation time was 500 (range 463-541) min, with an estimated blood loss of 762 (range 600-1,050) ml. Mean follow-up time was 6.3 (range 3.5-12.4) years. After PVCR, the mean Cobb angle for scoliosis was reduced from 69° (range 50-99°) to 29° (5-44°) and the sagittal curvature (kyphosis) from 126° (87-151°) to 61° (47-75°). The mean correction of scoliosis was 57 % (18-92°) and of kyphosis, 51 % (44-62°). There were no spinal cord-related complications. In three patients, spinal instrumentation for growth guidance (fusion less growing rod technique) was applied. Two patients had complications: one patient had a complication of anesthesia, halo pin failure, and revision surgery with extension of the instrumentation cranially due to loss of correction; the second patient had a postoperative infection, which required plastic reconstructive measures. CONCLUSION: PVCR appears to be an effective technique to treat severe EOSD. There are important differences in its use in young children when compared with older patients. In patients with EOSD, additional surgical procedures are often necessary during growth, and hence non-fusion instrumentation beyond the vertebral resection site is advantageous, as it permits spinal growth and the later addition of fusion.

Validity of a single-item measure to assess leg or back pain as the predominant symptom in patients with degenerative disorders of the lumbar spine.

PURPOSE: Recent studies suggest that the location of predominant pain (back or leg) can be a significant predictor of the outcome of surgery for degenerative spinal disorders. However, others challenge the notion that the predominant symptom can be reliably identified. This study examined the validity of a single item used to determine the most troublesome symptom. METHODS: A total of 2,778 patients with degenerative disorders of the lumbar spine scheduled for surgery with the goal of pain relief completed a questionnaire enquiring as to their most troublesome symptom ["main symptom"; back pain (BACK) or leg/buttock pain (LEG)]. They also completed separate 0-10 graphic rating scales for back pain (LBP) and leg/buttock pain (LP) intensity. Receiver operating characteristics (ROC) analysis was used to determine the accuracy with which the "LP minus LBP" score was able to classify patients into their declared "main symptom" group. Sub-studies evaluated the test-retest reliability of the patients' self-rated pain scores (N = 45) and the agreement between the main symptom declared by the patient in the questionnaire and that documented by the surgeon after the clinical consultation (N = 118). RESULTS: Test-retest reliability of the back and leg pain scores was good (ICC2,1 of 0.8 for each), as was patient-surgeon agreement regarding the main symptom (BACK or LEG) (κ value 0.79). In the BACK group, the mean values for pain intensity were 7.3 ± 2.0 (LBP) and 5.2 ± 2.9 (LP); in the LEG group, they were 4.3 ± 2.9 (LBP) and 7.5 ± 1.9 (LP). The area under the curve for the ROC was 0.95 (95 % CI 0.94-0.95), indicating excellent discrimination between the BACK and LEG groups based on the "LP minus LBP" scores. A cutoff score >0.0 for "LP minus LBP" score gave optimal sensitivity and specificity for indicating membership of the LEG group (sensitivity 79.1%, specificity 95.7%). CONCLUSIONS: The responses on the single item for the "main symptom" were in good agreement with the differential ratings on the 0-10 pain scales for LBP and LP intensity. The cutoff >0 for "LP minus LBP" for classifying patients as LEG pain predominant seemed appropriate and suggests good concurrent validity for the single-item measure. The single item may be of use in sub-grouping patients with the same disorder (e.g. spondylolisthesis) or as an indication in surgical decision-making.

The influence of comorbidity on the risks and benefits of spine surgery for degenerative lumbar disorders.

PURPOSE: The ageing of the population will see a growing number of patients presenting for spine surgery with appropriate indications but numerous medical comorbidities. This complicates decision-making, requiring that the likely benefit of surgery (outcome) be carefully weighed up against the potential risk (complications). We assessed the influence of comorbidity on the risks and benefits of spine surgery. METHODS: 3,549/4,053 patients with degenerative lumbar disorders, undergoing surgery with the goal of pain relief, completed the multidimensional Core Outcome Measures Index (COMI; scored 0-10) before and 12 months after surgery. At 12 months postoperatively, they also rated the global treatment outcome and their satisfaction with care. Using the Eurospine Spine Tango Registry, surgeons documented surgical details, American Society of Anesthesiologists comorbidity (ASA) grades and perioperative surgical and general complications. RESULTS: 29.0% patients were rated as ASA1 (normal healthy), 45.7% as ASA2 (mild/moderate systemic disease), 24.9% as ASA3 (severe), and just 0.4% as ASA4 (life-threatening). In going from ASA1 to ASA3 (ASA4 group too small), surgical complications increased significantly from 5.0 to 14.5% and general complications increased from 2.9 to 15.7%; 12-month outcomes showed a corresponding decline, with a good global outcome being reported by 79% ASA1 patients, 76% ASA2, and 68% ASA3. Satisfaction with treatment was 87, 85, and 79%, respectively, and reduction in COMI was 4.2 ± 2.9, 3.7 ± 3.0, and 3.4 ± 3.0 points, respectively. Multiple regression analysis revealed a significant (p < 0.0001) independent effect of ASA grade on both complications and outcome. CONCLUSION: The negative impact of comorbidity on the outcome of spine surgery has not been well investigated/quantified to date. The ASA grade may be helpful in producing algorithms for decision-making and preoperative counselling regarding the corresponding risks and benefits of surgery.

Multi-scale entropy assessment of magnetoencephalography signals in schizophrenia.

Schizophrenia is a severe disruption in cognition and emotion, affecting fundamental human functions. In this study, we applied Multi-Scale Entropy analysis to resting-state Magnetoencephalography data from 54 schizophrenia patients and 98 healthy controls. This method quantifies the temporal complexity of the signal across different time scales using the concept of sample entropy. Results show significantly higher sample entropy in schizophrenia patients, primarily in central, parietal, and occipital lobes, peaking at time scales equivalent to frequencies between 15 and 24 Hz. To disentangle the contributions of the amplitude and phase components, we applied the same analysis to a phase-shuffled surrogate signal. The analysis revealed that most differences originate from the amplitude component in the δ, α, and ß power bands. While the phase component had a smaller magnitude, closer examination reveals clear spatial patterns and significant differences across specific brain regions. We assessed the potential of multi-scale entropy as a schizophrenia biomarker by comparing its classification performance to conventional spectral analysis and a cognitive task (the n-back paradigm). The discriminative power of multi-scale entropy and spectral features was similar, with a slight advantage for multi-scale entropy features. The results of the n-back test were slightly below those obtained from multi-scale entropy and spectral features.

[Tumors and metastases of the upper cervical spine (C0-2). A special challenge]. / Tumoren und Metastasen der oberen Halswirbelsäule (C0-2). Eine besondere Herausforderung.

Tumors of the upper cervical spine are rare and represent less than 0.5 % of all spinal tumors. The types of tumor and the clinical presentation are as varied as the modalities used for treatment. The unique anatomy of the upper cervical spine with its high physical mobility means that biomechanical considerations and neighboring anatomical structures (e.g. vertebral artery, medulla oblongata, lower cranial nerves and pharynx) must be considered when creating a treatment plan. Finding a balance between complete tumor removal, the preservation and reestablishment of stability and function and the possible necessity for postoperative radiotherapy is of utmost importance and must be assessed on an individual basis. In this review paper some important points will be presented concerning the preparation of the patient, the planning of the operation and the surgical approach used in treating tumors of the craniocervical junction.

Fusionless posterior hemivertebra resection in a 2-year-old child with 16 years follow-up.

PURPOSE: We present the case of a 2-year-old patient with congenital scoliosis due to a lumbar hemivertebra. The current gold standard treatment of such an abnormality would be hemivertebra resection and short level posterior spinal fusion. However, due to the young age of the patient, we considered that application of a fusionless solution might offer advantages in terms of retaining normal segmental motion and the potential for growth. METHODS: The incarcerated hemivertebra was resected and the facet joints of the neighbouring vertebrae were joined to create a new functional motion segment and correct the kyphoscoliotic deformity. Transpedicular screws were inserted on the convex side in L2 and L3 and a tension band was applied. RESULTS: 16 years after the surgery, the patient was completely pain-free, motion of the lumbar spine was preserved and the physiological curvatures were maintained. CONCLUSION: To our knowledge a fusionless surgical solution for the treatment of a hemivertebra has never been described before. Although this is only a single case, the good result with a long follow-up suggests the technique is worthwhile considering when planning the treatment of a lumbar hemivertebra in very young children.

To fuse or not to fuse in lumbar degenerative spondylolisthesis: do baseline symptoms help provide the answer?

INTRODUCTION: Clinical symptoms in lumbar degenerative spondylolisthesis (LDS) vary from predominantly radiating pain to severe mechanical low back pain. We examined whether the outcome of surgery for LDS varied depending on the predominant baseline symptom and the treatment administered [decompression with fusion (D&F) or decompression alone (D)]. METHODS: 213 consecutive patients (69 ± 9 years; 155f, 58 m) participated. Inclusion criteria were LDS, maximum three affected levels, no previous surgery at the affected level, and D (N = 56) or D&F (N = 157) as the operative procedure. Pre-op and at 12 months' follow-up (FU), patients completed the multidimensional Core Outcome Measures Index (COMI) including 0-10 leg-pain (LP) and LBP scales. At 12 months' FU, patients rated global outcome which was then dichotomised into "good" and "poor". RESULTS: Pre-operatively, LBP and COMI scores were significantly worse (p < 0.05) in the D&F group than in the D group. The improvement in COMI at 12 months' FU was significantly greater for D&F than for D (p < 0.001) and was not influenced by the patient's declared "main problem" at baseline (back pain, leg pain, or neurological disturbances) (p > 0.05). There was a higher proportion (p = 0.01) of "good" outcomes at 12 months' FU in D&F (86%) than in D (70%). Multiple regression analysis, controlling for possible confounders, revealed treatment group to be the only significant predictor of outcome (adding fusion = better outcome). DISCUSSION: Our study indicated that LDS patients showed better patient-based outcome with instrumented fusion and decompression than with decompression alone, regardless of baseline symptoms. This may be due to the fact that the underlying slippage as the cause of the stenosis is better addressed with fusion.

Shorter and sweeter: the 16-item version of the SRS questionnaire shows better structural validity than the 20-item version in young patients with spinal deformity.

PURPOSE: In patients with adult spinal deformity, it was previously shown that 16 of the non-management items of the SRS-instrument showed a better fit to the theoretical four-factor model (pain, function, self-image, mental health) than did all 20 items. Whether the same phenomenon is observed in data from younger (< 20y) patients, for whom the questionnaire was originally designed, is not currently known. METHODS: Confirmatory factor analysis was used to evaluate the factor structure of the 20 non-management items of the SRS-instrument completed by 3618 young patients with spinal deformity (75.5% female; mean age, 15.0 ± 2.0 years) and of its equivalence across language versions (2713 English-speaking, 270 Spanish, 264 German, 223 Italian, and 148 French). The root mean square error of approximation (RMSEA) and comparative fit index (CFI) indicated model fit. RESULTS: Compared with the 20-item version, the 16-item solution significantly increased the fit (p < 0.001) across all language versions, to achieve good model fit (CFI = 0.96, RMSEA = 0.06). For both 16-item and 20-item models, equivalence across languages was not reached, with some items showing weaker item-loading for some languages, in particular German and French. CONCLUSION: In patients with adolescent idiopathic scoliosis, the shorter 16-item version showed a better fit to the intended 4-factor structure of the SRS-instrument. The wording of some of the items, and/or their equivalence across language versions, may need to be addressed. Questionnaire completion can be a burden for patients; if a shorter, more structurally valid version is available, its use should be encouraged.

The outcome of decompression surgery for lumbar herniated disc is influenced by the level of concomitant preoperative low back pain.

Decompression surgery is a common and generally successful treatment for lumbar disc herniation (LDH). However, clinical practice raises some concern that the presence of concomitant low back pain (LBP) may have a negative influence on the overall outcome of treatment. This prospective study sought to examine on how the relative severity of LBP influences the outcome of decompression surgery for LDH. The SSE Spine Tango System was used to acquire the data from 308 patients. Inclusion criteria were LDH, first-time surgery, maximum 1 affected level, and decompression as the only procedure. Before and 12 months after surgery, patients completed the multidimensional Core Outcome Measures Index (COMI; includes 0-10 leg/buttock pain (LP) and LBP scales); at 12 months, global outcome was rated on a Likert scale and dichotomised into "good" and "poor" groups. In the "good" outcome group, mean baseline LP was 2.8 (SD 3.1) points higher than LBP; in the "poor" group, the corresponding value was 1.1 (SD 2.9) (p < 0.001 between groups). Significantly fewer patients with back pain as their "main problem" had a good outcome (69% good) when compared with those who reported leg/buttock pain (84% good) as the main problem (p = 0.04). In multivariate regression analyses (controlling for age, gender, co-morbidity), baseline LBP intensity was a significant predictor of the 12-month COMI score, and of the global outcome (each p < 0.05) (higher LBP, worse outcome). In conclusion, patients with more back pain showed significantly worse outcomes after decompression surgery for LDH. This finding fits with general clinical experience, but has rarely been quantified in the many predictor studies conducted to date. Consideration of the severity of concomitant LBP in LDH may assist in establishing realistic patient expectations before the surgery.