Introduction: With a life of over five years, Spine Tango can be considered the first truly International Spine Registry. The Swedish Spine Registry has already shown the feasibility of a registry on a national level. But, there is a need for an international spine registry allowing a benchmarking on an international level. Here we demonstrate the genesis of questionnaire development, the constantly increasing activity, and limitations of the International Spine Registry Spine Tango. Methods: From 2002 until 2007 about 9000 datasets were submitted by 28 hospitals in nine countries worldwide. Three different generations of Spine Tango questionnaires were used for documentation. Results: To cope with varying international administrative issues and legal requirements of data anonymisation, national Spine Tango modules are necessary. Four national Spine Tango modules are in operation to date, another three modules are in the process of roll-out. Considering all these participants, Spine Tango will soon expand to include data from 52 hospitals in 18 countries. One-fourth of these hospitals are University Hospitals, which are destined to take the lead in the Spine Tango registry as opinion leading hospitals. Although the number of participants is steadily growing, no country is yet represented with a sufficient number of hospitals. Indisputably, a marketing concept is needed. An acquisition of new centres via national spine societies seems an obvious strategic approach. Further limitations of Spine Tango include the low number and short duration of follow-ups and the lack of sufficiently detailed patient based data on subgroup level. Discussion: Spine Tango has achieved a firm position as international spine registry and with its increasing acceptance it is also gaining importance. The strengths of Spine Tango include a potentially very large network, the participation of a specialized international society and an academic partner with expertise and extensive experience in registry implementation. Data analysis from Spine Tango is possible but complicated by the incompatibility of generations one and two with the more recent generation three. Consequently findings cannot yet be generalized to any specific country or patient population. Nevertheless, the potential benefits of the project for the whole spine community become increasingly visible. In the near future, the established Spine Tango version three with standardised patient based data will make outcome evaluations possible. In parallel to the International Spine Registry Spine Tango, a National Spine Registry in Australia could be set up – comparable to AOA’s National Joint Replacement Registry

Aims. The British Spine Registry (BSR) was introduced in May 2012 to be used as a web-based database for spinal surgeries carried out across the UK. Use of this database has been encouraged but not compulsory, which has led to a variable level of engagement in the UK. In 2019 NHS England and NHS Improvement introduced a new Best Practice Tariff (BPT) to encourage input of spinal surgical data on the BSR. The aim of our study was to assess the impact of the spinal BPT on compliance with the recording of surgical data on the BSR. Methods. A retrospective review of data was performed at a tertiary spinal centre between 2018 to 2020. Data were collated from electronic patient records, theatre operating lists, and trust-specific BSR data. Information from the BSR included operative procedures (mandatory), patient consent, email addresses, and demographic details. We also identified Healthcare Resource Groups (HRGs) which qualified for BPT. Results. A total of 3,587 patients were included in our study. Of these, 1,684 patients were eligible for BPT. Between 2018 and 2019 269/974 (28%) records were complete on the BSR for those that would be eligible for BPT. Following introduction of BPT in 2019, 671/710 (95%) records were complete having filled in the mandatory data (p < 0.001). Patient consent to data collection also improved from 62% to 93%. Email details were present in 43% of patients compared with 68% following BPT introduction. Conclusion. Our study found that following the introduction of a BPT, there was a statistically significant improvement in BSR record completion compliance in our unit. The BPT offers a financial incentive which can help generate further income for trusts. National data input into the BSR is important to assess patient outcome following spinal surgery. The BSR can also aid future research in spinal surgery. Cite this article: Bone Jt Open 2021;2-3:198–201

The effective capture of outcome measures in the healthcare setting can be traced back to Florence Nightingale’s investigation of the in-patient mortality of soldiers wounded in the Crimean war in the 1850s. Only relatively recently has the formalised collection of outcomes data into Registries been recognised as valuable in itself. With the advent of surgeon league tables and a move towards value based health care, individuals are being driven to collect, store and interpret data. Following the success of the National Joint Registry, the British Association of Spine Surgeons instituted the British Spine Registry. Since its launch in 2012, over 650 users representing the whole surgical team have registered and during this time, more than 27 000 patients have been entered onto the database. There has been significant publicity regarding the collection of outcome measures after surgery, including patient-reported scores. Over 12 000 forms have been directly entered by patients themselves, with many more entered by the surgical teams. Questions abound: who should have access to the data produced by the Registry and how should they use it? How should the results be reported and in what forum?. Cite this article: Bone Joint J 2015;97-B:871–4

Introduction: As an example of possibilities of Spine Tango we extracted data on dural tears, one of the most frequent types of complications in posterior spinal fusion. Little is known about their predictors. This study examined which factors predict the occurrence of dural tears in posterior spinal fusion. Methods: Prospective consecutive documentation of hospital based interventions with an evidence level 2++. Between 05/2005 and 11/2006 data of 3437 patients were documented in the registry. 929 patients, who had been treated with posterior spinal fusion after opening of the spinal canal, were included in this study. Median age was 62.7 yrs (min 12.5, max 90.5 yrs) with a female to male ratio of 2:1. In 18 of 929 cases a dural tear occurred. Dural tears being the most frequent type of complications in the registry were chosen as dependent outcome variable (3–6). Multiple linear regression with stepwise elimination was performed on potential predictor-variables of the occurrence of dural tears. Benchmarking compared the performance of single hospitals with international peers. Results: Hospital (p=0.02) and number of segments of fusion (p=0.018) were found to be predictors of the occurrence of dural tears in posterior spinal fusion. Number of fusions per hospital (min 25, max 526) and academic status of hospital had no influence on the rate of dural tears. Fusions of four and more segments showed an increase of the rate of dural tears by a factor of three compared to fusions of less than four segments. There was no significant difference between fusions of one segment and fusions of two or three segments (1.3 vs. 1.9%) as well as between fusions of four or five segments and fusions of more than five segments (4.6 vs. 4.2%). Differences between hospitals remained when benchmarking dural lesions with case mix. Discussion: The feasibility of data analysis and benchmarking from the International Spine Registry Spine Tango could be demonstrated. Predictors of dural tears in posterior spinal fusion are. hospital and. number of segments of fusion. In fusions of four and more segments a threefold higher risk of dural tears in comparison to fusions of less than four segments should be taken into consideration. A subgroup analysis on the predictor-variable hospital should be performed assessing further covariates. However, this goes beyond the possibilities of documentation in this international spine registry

Aims. Scoliosis is a lateral curvature of the spine with associated rotation, often causing distress due to appearance. For some curves, there is good evidence to support the use of a spinal brace, worn for 20 to 24 hours a day to minimize the curve, making it as straight as possible during growth, preventing progression. Compliance can be poor due to appearance and comfort. A night-time brace, worn for eight to 12 hours, can achieve higher levels of curve correction while patients are supine, and could be preferable for patients, but evidence of efficacy is limited. This is the protocol for a randomized controlled trial of ‘full-time bracing’ versus ‘night-time bracing’ in adolescent idiopathic scoliosis (AIS). Methods. UK paediatric spine clinics will recruit 780 participants aged ten to 15 years-old with AIS, Risser stage 0, 1, or 2, and curve size (Cobb angle) 20° to 40° with apex at or below T7. Patients are randomly allocated 1:1, to either full-time or night-time bracing. A qualitative sub-study will explore communication and experiences of families in terms of bracing and research. Patient and Public Involvement & Engagement informed study design and will assist with aspects of trial delivery and dissemination. Discussion. The primary outcome is ‘treatment failure’ (Cobb angle progression to 50° or more before skeletal maturity); skeletal maturity is at Risser stage 4 in females and 5 in males, or ‘treatment success’ (Cobb angle less than 50° at skeletal maturity). The comparison is on a non-inferiority basis (non-inferiority margin 11%). Participants are followed up every six months while in brace, and at one and two years after skeletal maturity. Secondary outcomes include the Scoliosis Research Society 22 questionnaire and measures of quality of life, psychological effects of bracing, adherence, anxiety and depression, sleep, satisfaction, and educational attainment. All data will be collected through the British Spine Registry. Cite this article: Bone Jt Open 2023;4(11):873–880

As an example of benchmarking in spinal surgery using Spine Tango, we extracted data on dural tears, one of the most frequent types of complications in posterior spinal fusion. Little is known about their predictors. This study examined which factors predict the occurrence of dural tears in posterior spinal fusion.

Prospective consecutive documentation of hospital based interventions with an evidence level 2++. Between May 2005 and November 2006 data of 3437 patients were documented in the registry. Nine hundred and twenty nine patients, who had been treated with posterior spinal fusion after opening of the spinal canal, were included in this study. Dural tears being the most frequent type of complications in the registry were chosen as dependent outcome variable. Multiple linear regression with stepwise elimination was performed on potential predictor-variables of the occurrence of dural tears. Benchmarking compared the performance of single hospitals with international peers. Median age was 62.7 years (min 12.5, max 90.5 yrs) with a female to male ratio of 2:1. In 18 of 929 cases a dural tear occurred. Hospital (p=0.02) and number of segments of fusion (p=0.018) were found to be predictors of the occurrence of dural tears in posterior spinal fusion. Number of fusions per hospital (min 25, max 526) and academic status of hospital had no influence on the rate of dural tears. Fusions of four and more segments showed an increase of the rate of dural tears by a factor of three compared to fusions of less than four segments. There was no significant difference between fusions of one segment and fusions of two or three segments (1.3 vs. 1.9%) as well as between fusions of four or five segments and fusions of more than five segments (4.6 vs. 4.2%). Differences between hospitals remained when benchmarking dural tears with case mix.

Predictors of dural tears in posterior spinal fusion are

hospital and

In fusions of four and more segments a threefold higher risk of dural tears in comparison to fusions of less than four segments should be taken into consideration.

Aims. The aim of this study was to identify factors associated with poor outcome following coccygectomy on patients with chronic coccydynia and instability of the coccyx. Methods. From the Danish National Spine Registry, DaneSpine, 134 consecutive patients were identified from a single centre who had coccygectomy from 2011 to 2019. Patient demographic data and patient-reported outcomes, including pain measured on a visual analogue scale (VAS), Oswestry Disability Index (ODI), EuroQol five-dimension five-level questionnaire, and 36-Item Short-Form Health Survey questionnaire (SF-36) were obtained at baseline and at one-year follow-up. Patient satisfaction was obtained at follow-up. Regression analysis, including age, sex, smoking status, BMI, duration of symptoms, work status, welfare payment, preoperative VAS, ODI, and SF-36 was performed to identify factors associated with dissatisfaction with results at one-year follow-up. Results. A minimum of one year follow-up was available in 112 patients (84%). Mean age was 41.9 years (15 to 78) and 97 of the patients were female (87%). Regression showed no statistically significant association between the investigated prognostic factors and a poor outcome following coccygectomy. The satisfied group showed a statistically significant improvement in patient-reported outcomes at one-year follow-up from baseline, whereas the dissatisfied group did not show a significant improvement. Conclusion. We did not identify factors associated with poor outcome following coccygectomy. This suggests that neither of the included parameters should be considered contraindications for coccygectomy in patients with chronic coccydynia and instability of the coccyx. Cite this article: Bone Jt Open 2021;2(7):540–544

Aims. The aim of this study was to investigate the efficacy of coccygectomy in patients with persistent coccydynia and coccygeal instability. Methods. The Danish National Spine Registry, DaneSpine, was used to identify 134 consecutive patients who underwent surgery, performed by a single surgeon between 2011 and 2019. Routine demographic data, surgical variables, and patient-reported outcomes, including a visual analogue scale (VAS) (0 to 100) for pain, Oswestry Disability Index (ODI), EuroQol five-dimension questionnaire (EQ-5D), and the Physical Component Score (PCS) and Mental Component Score (MCS) of the 36-Item Short-Form Health Survey questionnaire (SF-36) were collected at baseline and one-year postoperatively. Results. A total of 112 (84%) patients with a minimum follow-up of one year had data available for analysis. Their mean age was 41.9 years, and 15 (13%) were males. At 12 months postoperatively, there were statistically significant improvements (p < 0.001) from baseline for the mean VAS for pain (70.99 to 35.34), EQ-5D (0.52 to 0.75), ODI (31.84 to 18.00), and SF-36 PCS (38.17 to 44.74). A total of 78 patients (70%) were satisfied with the outcome of treatment. Conclusion. Patients with persistent coccydynia and coccygeal instability resistant to nonoperative treatment may benefit from coccygectomy. Cite this article: Bone Joint J 2021;103-B(3):542–546

When a suspicious spine lesion is identified, an accurate diagnosis based on tissue biopsy is needed to direct towards the correct treatment protocol. Several studies concluded that the percutaneous fluoroscopy guided biopsy of vertebral lesions is a safe, effective and accurate diagnostic tool and is preferred over open techniques when possible. The aim of this study was to review percutaneous fluoroscopy guided transpedicular spinal biopsies at a tertiary hospital over a 6-year period. The research design was a retrospective review of patients who underwent percutaneous transpedicular spinal biopsies under fluoroscopy guidance at a tertiary hospital over a six year period (1st January 2016 to the 31st December 2021). The spine theatre registry and hospital records system were used as the source for data collection. Statistical analysis was conducted to determine the effectiveness of transpedicular spinal biopsies, compare spinal pathology amongst age and gender and to identify any complications. The study analysed 180 biopsies, 120 yielding a positive result (66.67%). Of these 8.9% were pyogenic infection, 18.4% neoplasm, 36.7% Tuberculosis and 2.7% other. There were 75 males and 105 females with an age range between 9 and 86 years and mean age of 43.44. Comparing age and gender found no statistical significance (p = 0.778). Comparing biopsy result and gender showed no statistical significant relationship (p = 0.970). Comparison of biopsy result with age showed no statistical significant association (p = 0,545). Four complications were identified (2.22%). The study showed that fluoroscopy guided percutaneous transpedicular biopsy is an effective and safe modality in obtaining spinal specimens in all age groups for a wide spectrum of spinal pathological lesions

The MAGnetic Expansion Control (MAGEC) system is used increasingly in the management of early-onset scoliosis. Good results have been published, but there have been recent reports identifying implant failures that may be associated with significant metallosis surrounding the implants. This article aims to present the current knowledge regarding the performance of this implant, and the potential implications and strategies that may be employed to identify and limit any problems. We urge surgeons to apply caution to patient and construct selection; engage in prospective patient registration using a spine registry; ensure close clinical monitoring until growth has ceased; and send all explanted MAGEC rods for independent analysis. The MAGEC system may be a good instrumentation system for the treatment of early-onset scoliosis. However, it is innovative and like all new technology, especially when deployed in a paediatric population, robust systems to assess long-term outcome are required to ensure that patient safety is maintained. Cite this article: Bone Joint J 2017;99-B:708–13

Background. Depression, anxiety, catastrophising, and fear-avoidance beliefs are some of the so-called “yellow flags” that predict a poor outcome in back patients. Many surgeons have difficulty assessing yellow flags, perhaps due to the complexity of existing instruments and time constraints during consultations. We developed a brief tool to allow the systematic evaluation of core flags. Methods. Data from 4 questionnaires (ZUNG depression (N=399); Hospital Anxiety and Depression Scale (Anxiety-subscale) (N=308); Pain Catastrophising (N=766); Fear Avoidance Beliefs (N=736)) were analysed to identify the respective single item that best represented the full scale score. The 4 items formed the “Core Yellow Flags Index” (CYFI). 1'768 patients completed CYFI and a Core Outcome Measures Index (COMI) preoperatively, and COMI 3 and 12mo later (FU). Results. The individual flag items correlated with their corresponding full-length questionnaires: 0.71 (depression), 0.81 (catastrophising), 0.77 (anxiety), 0.83 (fear avoidance beliefs). Cronbach's α for the 4 items was 0.79. Structural equation modelling revealed that CYFI explained a unique proportion of the variance in COMI at 3 months' FU (β=0.23, p< 0.001) and also at 12 months FU (β=0.20, p< 0.001). Conclusion. The 4-item CYFI proved to be a simple, practicable tool for routinely assessing key psychological attributes in spine surgery patients; it made a relevant contribution in predicting postoperative outcome. CYFI's items were similar to those in the “STarTBack screening-tool”, used in primary care to predict back pain chronicity, further substantiating its validity. Its wider use may help improve the accuracy of predictive models derived using spine registry data. No conflicts of interest. No funding obtained

Background: context: Length of hospital stay (LOS) varies widely within patients with posterior spinal fusion. So far there is little evidence on its co-variates. Purpose: This study examined which co-variates influence LOS in posterior spinal fusion. Study design: Prospective consecutive documentation of hospital based interventions in the international spine registry Spine Tango. Patient sample: Between 05/2005 and 11/2006 data of 3437 patients were documented in the registry. 790 patients with degenerative spinal disease (614) or spondylolisthesis (176), who had been treated with posterior decompression and spinal fusion, were included in this study. Median age was 62.8 yrs (min 13.2 yrs, max 89.8 yrs) with a female to male ratio of 2:1. Median LOS was 11 days (IQR 8–14 d). Outcome measures: LOS was chosen as dependent outcome variable. Methods: Multiple linear regression was performed on following independent variables: age, gender, main pathology, number of spinal segments of posterior fusion, level of fusion, number of previous spinal surgeries, operation time, clinic (number of fusions, academic status), surgeon credentials, type of fusion (sole fusion, fusion + instrumentation, fusion + instrumentation + cage). Results: Clinic (p< 0.0001) was found to be a highly significant co-variate for LOS (min 7 d, max 14 d). Number of fusions per clinic (min 25, max 434) and academic status of clinic had no influence on LOS. Further significant covariates were surgeon credentials (surgeons in training: 8.5 d, specialised spine surgeons: 11 d, orthopaedic or neurosurgeons: 12 d; p=0.001), number of spinal segments of posterior fusion (1 segment: 10 d, 2–3 segments: 12 d, 4–5 segments: 12.5 d, > 5 segments: 15 d; p=0.002), and age group (< 50 yrs: 9 d, 50–59 yrs: 11 d, 60–69 yrs: 12 d, ≥70 yrs: 13 d; p=0.01). Borderline significance was found for gender (women: 12 d, men: 10 d; p=0.05). All other variables showed no influence on LOS. Conclusion: Co-variates of LOS of patients with posterior spinal fusion are clinic, independent of number of spinal surgeries per clinic and academic status of clinic, surgeon credentials, number of segments of fusion, age group, and gender. A short LOS in surgeries performed by surgeons in training is explained by a smaller number of segments of fusions in these procedures. A subgroup analysis on the co-variate clinic should be performed assessing further explanatory variables. However, this goes beyond the possibilities of documentation in a spine registry

Background. PROMs have become an integral assessment tool of clinical effectiveness and patient satisfaction. To date, PROMs for lumbar discectomy are not an NHS requirement, although voluntary collection via the British Spine Registry is encouraged. Despite this, PROMs for day case microdiscectomy is scarcely reported. We present PROMs for day case microdiscectomy at Lancashire Teaching Hospitals. Aims. 1). To review PROMs to quantify leg pain, back pain, EQ5D and ODI scores. 2). Evaluate PROMs data collection compliance. Methods. We studied PROMs data, taken prospectively as part of routine clinical care for all patients who underwent single level day case microdiscectomy between January 2013 to December 2015. PROMs included VAS for back and leg pain, EQ5D and ODI scores. Preoperative PROMs were compared to all available postoperative PROMs at 3 months, 6 months, 12 months and 24 months. Paired student T-tests were used to compare preoperative to postoperative scores. Results. Preoperative PROMs were recorded for 132 patients. Postoperative PROMs were recorded for 48 patients at 3 months, 51 patients at 6 months, 37 patients at 12 months and 15 patients at 24 months. Significant postoperative improvements (p<0.05) were found at all time points for back pain, leg pain, EQ5D and ODI, with the exception EQ5D at 24 months (p = 0.10). Conclusion. There was significant improvement in VAS back and leg scores, as well as ODI scores over 24 months. Further work is needed to improve compliance with postoperative PROMs and to optimise the benefit of these health assessment tools. No conflicts of interest. No funding obtained

Aims. Repeated lumbar spine surgery has been associated with inferior clinical outcomes. This study aimed to examine and quantify the impact of this association in a national clinical register cohort. Methods. This is a population-based study from the Norwegian Registry for Spine surgery (NORspine). We included 26,723 consecutive cases operated for lumbar spinal stenosis or lumbar disc herniation from January 2007 to December 2018. The primary outcome was the Oswestry Disability Index (ODI), presented as the proportions reaching a patient-acceptable symptom state (PASS; defined as an ODI raw score ≤ 22) and ODI raw and change scores at 12-month follow-up. Secondary outcomes were the Global Perceived Effect scale, the numerical rating scale for pain, the EuroQoL five-dimensions health questionnaire, occurrence of perioperative complications and wound infections, and working capability. Binary logistic regression analysis was conducted to examine how the number of previous operations influenced the odds of not reaching a PASS. Results. The proportion reaching a PASS decreased from 66.0% (95% confidence interval (CI) 65.4 to 66.7) in cases with no previous operation to 22.0% (95% CI 15.2 to 30.3) in cases with four or more previous operations (p < 0.001). The odds of not reaching a PASS were 2.1 (95% CI 1.9 to 2.2) in cases with one previous operation, 2.6 (95% CI 2.3 to 3.0) in cases with two, 4.4 (95% CI 3.4 to 5.5) in cases with three, and 6.9 (95% CI 4.5 to 10.5) in cases with four or more previous operations. The ODI raw and change scores and the secondary outcomes showed similar trends. Conclusion. We found a dose-response relationship between increasing number of previous operations and inferior outcomes among patients operated for degenerative conditions in the lumbar spine. This information should be considered in the shared decision-making process prior to elective spine surgery. Cite this article: Bone Joint J 2023;105-B(4):422–430

Aims

To identify the incidence and risk factors for five-year same-site recurrent disc herniation (sRDH) after primary single-level lumbar discectomy. Secondary outcome was the incidence and risk factors for five-year sRDH reoperation.

Aims. The number of patients undergoing surgery for degenerative cervical radiculopathy has increased. In many countries, public hospitals have limited capacity. This has resulted in long waiting times for elective treatment and a need for supplementary private healthcare. It is uncertain whether the management of patients and the outcome of treatment are equivalent in public and private hospitals. The aim of this study was to compare the management and patient-reported outcomes among patients who underwent surgery for degenerative cervical radiculopathy in public and private hospitals in Norway, and to assess whether the effectiveness of the treatment was equivalent. Methods. This was a comparative study using prospectively collected data from the Norwegian Registry for Spine Surgery. A total of 4,750 consecutive patients who underwent surgery for degenerative cervical radiculopathy and were followed for 12 months were included. Case-mix adjustment between those managed in public and private hospitals was performed using propensity score matching. The primary outcome measure was the change in the Neck Disability Index (NDI) between baseline and 12 months postoperatively. A mean difference in improvement of the NDI score between public and private hospitals of ≤ 15 points was considered equivalent. Secondary outcome measures were a numerical rating scale for neck and arm pain and the EuroQol five-dimension three-level health questionnaire. The duration of surgery, length of hospital stay, and complications were also recorded. Results. The mean improvement from baseline to 12 months postoperatively of patients who underwent surgery in public and private hospitals was equivalent, both in the unmatched cohort (mean NDI difference between groups 3.9 points (95% confidence interval (CI) 2.2 to 5.6); p < 0.001) and in the matched cohort (4.0 points (95% CI 2.3 to 5.7); p < 0.001). Secondary outcomes showed similar results. The duration of surgery and length of hospital stay were significantly longer in public hospitals. Those treated in private hospitals reported significantly fewer complications in the unmatched cohort, but not in the matched cohort. Conclusion. The clinical effectiveness of surgery for degenerative cervical radiculopathy performed in public and private hospitals was equivalent 12 months after surgery. Cite this article: Bone Joint J 2023;105-B(1):64–71

Aims

The aim of the study was to determine if there was a direct correlation between the pain and disability experienced by patients and size of their disc prolapse, measured by the disc’s cross-sectional area on T2 axial MRI scans.

Introduction: Dural tears are one of the most frequent type of complication in posterior spinal fusion with little known about their predictors. Method: Prospective consecutive study with an evidence level 2++ of 42 patients in the international spine registry Spine Tango, who had been treated between 05/2005 and 8/2008 with posterior spinal fusion after opening of the spinal canal. Median age was 62.7 yrs (min 12.5, max 90.5 yrs) with a female to male ratio of 2:1. In 42 of 1575 cases a dural tear occurred being the most frequent type of complication in our study sample. Multiple linear regression was performed on potential predictor-variables of the occurrence of dural tears. Results: Hospital (p=0.02) and number of segments of fusion (p=0.018) were found to be predictors of the occurrence of dural tears in posterior spinal fusion. Number of fusions per hospital (min 25, max 526) and academic status of hospital had no influence on the rate of dural tears. Fusions of four and more segments showed an increase of the rate of dural tears by three compared to fusions of less than four segments. Conclusion: Predictors of dural tears in posterior spinal fusion are hospital, independent of number of spinal surgeries and academic status of hospital, and number of segments of fusion. In fusions of four and more segments a threefold higher risk of dural tears in comparison to fusions of less than four segments should be taken into consideration