Session 11: Spine

Fredag den 24. oktober
09:00 – 10:30
Lokale: Stockholm/Copenhagen
Chairmen: Mikkel Østerheden Andersen / Søren Eiskjær

109. A modification of the Tokuhashi Revised score improves prognostic precision in patients with metastatic spinal cord compression.
Søren Schmidt Morgen, Martin Gehrchen, Sebastian Bjørck, Claus Falck Larsen, Svend Aage Engelholm, Benny Dahl
Spine Section, Department of Orthopedic Surgery , Copenhagen University Hospital, Rigshospitalet ; Trauma Center, Copenhagen University Hospital, Rigshospitalet ; Department of Radiation and Oncology, Copenhagen University Hospital, Rigshospitalet

Background: Patients suffering from metastatic spinal cord compression (MSCC) are routinely evaluated with pre-operative prognostic scoring systems. The most well known scoring system is the Tokuhashi Revised score (TR), but recent studies have proposed a modification of the TR due to lack of precision.
Purpose / Aim of Study: To modify the TR in order to improve the prognostic precision.
Materials and Methods: In 2011 and 2012 a total of 1143 consecutive patients admitted with MSCC were prospectively included and variables for the TR score were collected. In the 2011 cohort each component of the TR including primary cancer diagnosis was analyzed regarding prognostic ability by Cox regression analysis. Based on these findings a modified TR score (MTR) was defined. New prognostic groups were determined using Receiver Operating Characteristics (ROC) analysis for survival < 6 months, >= 6 months, and >= 12 months. These prognostic groups were used to compare the TR and the MTR in the 2012 cohort based on Kaplan-Meier (KM) survival curves and ROC analysis.
Findings / Results: There were no significant differences between the 2011 and the 2012 cohort regarding age and gender distribution. The mean age was 66 years (range 20-97) and the most common primary tumor sites were prostate (21%) and lung (20%). In the 2012 cohort the KM curves showed that the actual survival for each prognostic group was separated more accurate with the MTR compared to the TR. The areas under the ROC curves were significant larger for the MTR compared with the TR. The ROC area were for < 6 months survival, MTR = 0.71 and TR = 0.65; p = 0.003, for >= 6 months survival, MTR = 0.71 and TR = 0.65; p = 0.003, for >= 12 months survival MTR = 0.72 and TR= 0.67; p = 0.0015.
Conclusions: A modification of the TR can improve the precision in the estimation of survival among patients with MSCC.

110. Reliability and validity of the Danish version of SRS 22r
Ane Simony, Karen Højmark Hansen, Leah Carreon, Mikkel Østerheden Andersen
Rygkirurgisk Afdeling, Middelfart Sygehus; Research Department for Spine Surgery, Norton Spine Center

Background: Adolescent idiopathic scoliosis (AIS) is a three dimensional disease of the spine, with a Cobb angel greater than 10º. AIS affects children in the age of 12-16, and develops during the growth spurt. Treatment of AIS is correction of the spine by either brace treatment or surgery. Haher et al created the SRS 22 questionnaire as a tool to monitor health related quality of life in scoliosis patients, but no previous Danish version has been validated.
Purpose / Aim of Study: To evaluate the validity and reliability, of the Danish adapted version of SRS 22.
Materials and Methods: The SRS 22 were translated and cross cultural adapted, according to the guidelines from WHO. The SRS22 Danish version was distributed to 262 patients with scoliosis and 50 age matched controls, together with SF12. All data where analyzed by a independent statistician.
Findings / Results: A total of 207 questionnaires (79.2% response rate) were retrieved.165 questionnaires from scoliosis patients and 42 from healthy controls. No floor effects was noted. In the scoliosis patients, moderate ceiling effects were observed on the Satisfaction with Management domain. Reliability of the SRS-22 seemed good with a Cronbach á of 0.93 in scoliosis patients, 0.90 in healthy controls. In patients, good reliability was found for all domains: Pain, 0.88; Self-image, 0.87; Function, 0.89; Mental Health, 0.90; Satisfaction with Management, 0.68. The concurrent validity showed good reliability with an overall á of 0.88. The results were statistically significant at P <0.05. The discriminant validity was tested with a t-test. All domains differed significantly and reveal scoliosis patients have lower scores compared with the controls.
Conclusions: The Danish translated version of SRS 22 is valid, and can detect difference between patient with scoliosis and a age matched healthy control group.

111. Self-reported scoliosis is not a valid method for estimating concordance rates of Adolescent Idiopathic Scoliosis in a Danish twin population
Mikkel Andersen, Kirsten O. Kyvik , Karsten Thomsen , Ane Simony
Sector of Spine Surgery and Research, Region of Southern Denmark, Sygehus Lillebælt; Institute of Public Health, University of Southern Denmark; Sector of Spine Surgery, , Aleris

Background: The aetiology of adolescent idiopathic scoliosis is still unclear and the true mode of inheritance has yet to be established. From the Danish twin cohort concordance rates in monozygotic twins have previously been reported to be 0.13¬ and in dizygotic twins 0. Studies on concordance in twin pairs provide a basis for analysing the influence of genetic versus environmental factors.
Purpose / Aim of Study: To validate if self-reported scoliosis is a valid method to establish incidence and concordance rates in a twin population
Materials and Methods: All 46,418 twins registered in the Danish Twin Registry born from 1931 to 1982 were sent a questionnaire, which included questions about scoliosis. A sub group of 344 individuals with self- reported scoliosis were invited to a clinical and a radiologic examination together with their twin, in total 644 individuals/ 322 twin pairs. Zygosity was established by genetic testing.
Findings / Results: 203 individuals (31.5% of the cohort) participated. The total number of participants consisted of 95 twin pairs, where one or both twins had scoliosis and 13 individuals. 35 individuals (32.4%) of the 108 participants with self-reported scoliosis presented a clinical and radiological confirmed curve. Of these were 5 twin pairs (4 monozygotic pairs and 1 dizygotic pair) with scoliosis in both twins and 11 twin pairs with scoliosis in only one twin and 3 individuals where only one twin participated. Calculating concordance in twins with curves greater than 15 degrees, we found that the pairwise concordance rate was 0.4 (0.12-0.74) for monozygotic and 0.05 (0.01 -0.25) for dizygotic twin pairs, probandwise concordance was 0.45 for monozygotic and 0.1 for dizygotic pairs.
Conclusions: Self-reported scoliosis in a Danish twin population is not a valid method to establish the true concordance rates.

112. Investigating human VANGL1, as a candidate gene for adolescent idiopathic scoliosis
Malene Rask Andersen, Ane Simony, Lars Allan Larsen
Wilhelm Johannesen Centre for Functional Genome Research, Department of Cellular and Molecular Medic, Københavns Universitet; Rygkirurgisk afdeling, Middelfart Sygehus

Background: The human VANGL1 genes has been predicted to be associated with idiopathic scoliosis, as a mutation (c.676C>T, L226F) was identified in a family with dominant inheritance of the disease. Previous investigation of the gene revealed the candidate to segregate, with all but one family member. Adolescent idiopathic scoliosis (AIS) is generally considered multi-genic, but the determining genes remain yet to be characterised.
Purpose / Aim of Study: In this study we have examined VANGL1 as a contributor to the phenotype of AIS.
Materials and Methods: We have conducted automated Sanger sequencing of the seven coding exons of VANGL1 gene in a disease cohort of 170 AIS patients (n=340) and 177 controls (n=354). Localization of mutated VANGL1 proteins were investigeted in cell systems.
Findings / Results: Two novel mutations, each in separate individuals within the considered disease cohort, were identified. One mutation is situated in the third coding exon, which encodes the transmembrane parts of the VANGL protein. This mutation is a c.407T>A (L136N) conversion, for which the patient is heterozygotes. This mutation was also identified in the dizygotic unaffected twin of the patient. The second mutation was found in the seventh coding exon, which encode the C-terminal of the VANGL1 protein. This mutation is a c.1318T>G (F440V) conversion, for which the patient is also heterozygotes. Neither of the identified mutations was present in the sequenced controls or in 2000 Danish exomes. Currently, the cellular localization of wt and mutant VANGL1 protein are being investigated using immunofluorescence microscopy.
Conclusions: On behalf of the current results of this study we conclude that mutations in the VANGL1 gene may be a rare cause of AIS. Examination of the expression of VANGL1 in teenage-adult stages of life is wanted as well as examinations of effects.

113. Does obesity delay time of surgery for Lumbar Disc Herniation, and does it influence surgical outcome in 832 patients treated with discectomy.
Rikke Rousing, Ane Simony, Henrik Grønvall, Karen Højmark, Stefan Hummel, Mikkel Østerheden Andersen
Rygkirurgisk afdeling, Middelfart sygehus, Vejle sygehus

Background: Lumbar disc herniation (LDH) is associated with great morbidity and significant socioeconomics impact. Studies have shown that most LDH can be treated effective conservatively. However for the group of patients where pain and disability is unacceptable, surgical intervention provides effective clinical relief in many cases. Several factors may influence the outcome of surgery for LDH, including obesity and prolonged time of symptoms. Data from the Danish National Healthprofile 2010 state that 47% of the danish population is overweight (BMI ≥ 25) and about 13% is classified as obese (BMI ≥ 30).
Purpose / Aim of Study: To investigate if obesity is correlated with surgical outcome and whether overweight patients has a delayed time of surgery compared with non-obese patients.
Materials and Methods: 832 patients with first-time LDH were included in a Single-Center Study. Data were prospectively collected in DaneSpine, the Danish National Spine Register. The patient reported outcome measures (PROMs) EQ5D, SF36, ODI, VAS-leg and -back were correlated with duration of symptoms. A comparison between subgroups of BMI and 1-year follow-up PROMs were performed. Data was analysed with STATA.
Findings / Results: Overweight and obese patients have symptoms-relieve following LDH surgery, but the outcome is inferior to patients of normal weight. Patients with BMI ≥ 35 are treated conservatively for a longer time and have an inferior outcome.
Conclusions: Severe obesity delays time of surgery and influences the surgical outcome.

114. Moderate Precision of the Tokuhashi Revised Score and the Bauer Modified Score in Patients with Metastatic Spinal Cord Compression.
Søren Schmidt Morgen, Martin Gehrchen, Dennis Hallager Nielsen, Claus Falck Larsen, Svend Aage Engelholm, Benny Dahl
Spine Section, Department of Orthopedic Surgery, Copenhagen University Hospital, Rigshospitalet ; Trauma Center, Copenhagen University Hospital, Rigshospitalet ; Department of Radiation and Oncology, Copenhagen University Hospital, Rigshospitalet

Background: Estimated survival is an important element in the evaluation of patients with metastatic spinal cord compression (MSCC). The Tokuhashi Revised score (TR) has been recommended as a prognostic score in many studies, but two recent studies have showed that the Bauer Modified Score (BM) was the more accurate.
Purpose / Aim of Study: To compare the TR and the BM in the prediction of survival among patients surgically treated for MSCC.
Materials and Methods: From January 1st 2009 to December 31st 2011, a total of 246 MSCC patients were treated surgically for MSCC in one center. These patients were included in a cohort with a minimum of two years follow-up. The patients were scored with the TR and the BM scoring systems.
Findings / Results: The mean age on admission was 63 years (range 27-94) and 54% of the patients were men. The most common primary tumor-sites were lungs (24%) and breast (15%). The logrank test showed that each prognostic group in both scoring system were significantly different (p < 0.001). The Kaplan Meyer survival curves showed good prognostic value in each prognostic group for both of the scoring systems, but the specificity and sensitivity was moderate. In both scoring systems the prognostic groups with a short predicted survival had “longtime survivors” who lived longer than one-year (20% in the TR-group and 19% in the BM- group). For the prognostic groups with long estimated survival, a considerable proportion of the patients were dead within 6 months (27% in the BM and 31% in the TR).
Conclusions: This study showed that the TR and the BM ability to predict survival were almost equal. Both scoring systems performed well in categorizing patients in prognostic groups, but the moderate precision in predicting survival emphasizes that a modification may be necessary.

115. Morbidity and mortality of complex spine surgery: a prospective cohort study in 679 patients validating the SAVES system in a European population
Sven Karstensen, Tanvir Bari, Martin Gehrchen, John Street, Benny Dahl
SpineUnit, Department of Orthopaedic Surgery, Rigshospitalet and University of Copenhagen ; ICORD, University of British Columbia

Background: The Spine AdVerse Events Severity system (SAVES) has been found reliable and valid in two North American spine centers, providing precise information regarding all adverse events after complex spine surgery.
Purpose / Aim of Study: The purpose of the present study was to assess the generalizability of the SAVES system in a European population of patients, including pediatric patients, undergoing complex spine surgery.
Materials and Methods: All patients undergoing spinal surgery in the period January 1, 2013 through December 31, 2013 were prospectively included. A modified SAVES form was used, and a research coordinator collected all data prospectively. Once a week all patients were reviewed for additional events, validation of the data and clarification of any questions. The survival status was registered on January 31, 2014 to obtain 30-day survival.
Findings / Results: A total of 679 consecutive patients were included with 100% SAVES data completed. The in-hospital mortality was 1.3% and the 30-day mortality was 2.7 %; all occurring after emergency procedures. There was no significant difference between lengths of stay after elective or emergency surgery. The number of intraoperative AE’s was 162 and the number of postoperative AE’s was 1415; the most frequent event being postoperative electrolyte imbalance. 2.2% of the patients had postoperative infections requiring surgical revision. The frequency of postoperative AE’s was significantly higher in patients 65 years or older compared to young individuals (P=0.002).
Conclusions: The results confirm that a rigorous prospective system improves adverse event recognition, confirming the generalizability of the SAVES system to a non-Canadian populations including pediatric patients.

116. Clinical correlation of the SRS-Schwab Classification with HRQOL measures in a prospective non-US cohort of ASD patients
Dennis Hallager Nielsen, Lars Valentin Hansen, Casper Rokkjær Dragsted, Martin Gehrchen, Benny Dahl
Dept. of Orthopaedic Surgery, Rigshospitalet

Background: The SRS-Schwab adult spinal deformity (ASD) classification system is considered an important communication tool for spine surgeons as it summarizes the complex pathology of ASD in four coronal curve types with three sagittal modifiers (PI-LL, PT and SVA). The cut-off values separating level 0 from + have been proposed to predict severe disability defined by an Oswestry Disability Index (ODI) of more than 40. The clinical correlations of the classification system have only been evaluated using US ASD patients.
Purpose / Aim of Study: The aim of the present study was to assess the clinical correlations of the sagittal modifiers with various HRQOL measures in a prospective, consecutive non-US cohort of ASD patients.
Materials and Methods: Between March and August 2013 a total of 112 ASD patients aged >18 years having sufficient long standing X-rays taken at our out-patient clinic completed VAS scores for back pain, ODI, SRS22r, EQ5D and SF36 questionnaires. 14 patients were excluded due to predefined criteria. For each sagittal modifier the variation of score means/ranks across levels 0, + and ++ was assessed with one-way ANOVA/Kruskal-Wallis test.
Findings / Results: 98 patients were included with a median age of 64 years (range 18-85). 64% were female, and 49% had a history of previous deformity surgery. We found a significant variation for SF36 physical component summary (PCS) scores across the levels of all modifiers. Significant variation was also found for SRS22r total score across PI-LL and PT levels, EQ5D and VAS for back pain across PI-LL and SVA levels and ODI across SVA levels.
Conclusions: We showed that the SRS-Schwab classification modifiers are able to classify patients according to the SF36 PCS and various other HRQOL measures in a non-US cohort of ASD patients.

117. Providence Nighttime Bracing in adolescent idiopathic scoliosis
Ane Simony, Inge Beuschau , Lena Quisth , Mikkel Østerheden Andersen, Stig Mindedahl Jespersen
Rygkirurgisk Afdeling, Middelfart Sygehus; , Ortos, Odense; Rygkirurgisk sektor, Odense Universitets Hospital

Background: 6 years ago the primary conservative treatment of adolescent idiopathic scoliosis (AIS) in the southern part of Denmark, went from full time bracing to nighttime bracing.
Purpose / Aim of Study: To evaluate the effectiveness of nighttime bracing in AIS.
Materials and Methods: Patients diagnosed with AIS and skeletal immature. With an apex of the primary curve from TH7 and below and with a cobb angel between 20- 45 degrees. The patients were asked to wear the brace at least 7-8 hours pr. night. No other previous treatments were accepted and a follow up at least 6 months out of brace. The brace treatment was continued until two years post menarche or for male at the expected adult height. Cross-measured x-rays was used to compare the primary cobb angel, the in- brace correction and the outcome cobb angel. A decreased outcome cobb angle as well as the overcorrection of the curve measured in brace was recorded as zero. The brace treatment was considered failed if progression more than 5 degrees occurred and if surgery were performed.
Findings / Results: A total of 55 patients, 8 male and 47 female, with the mean age at 14 years (11-16.5) and the mean primary cobb at 31 degrees (20-41) were included in this study. The mean time of treatment was 18 month (5-59). After ended treatment the mean cob angle was 28 degrees (7-50), an average of no progression. The end results were 11 failures (6-15 degrees); equal 20 % and out of these 11 patients, 3 had surgery performed (5%).
Conclusions: The results show a good curve control and an acceptable 20 % failure rate, which is equal to other studies. The providens brace is an excellent alternative to standard conservative treatment. Larger studies are needed to establish the relationship between inbrace correction and curve progression.

118. Is the surgical outcome for lumbar disc herniations related to the duration of symptoms?
Christian Støttrup, Carsten Ernst, Dorte Clemmensen, Alexander Isenberg-Jørgensen, Randi Holm, Mikkel Østerheden Andersen
Rygkirurgisk sektor, Middelfart Sygehus, Vejle Sygehus

Background: Lumbar disc herniation (LDH) is associated with great morbidity and significant socio-economic impact in many parts of the world. Studies have shown that most LDH can be treated effectively with conservative management and the passage of time. However for the group of patients where pain and disability is unacceptable, surgical intervention provides effective clinical relief in many cases. Currently there is little consensus in the medical community on the timing of surgery for patients suffering from radicular pain due to LDH. Reports based on the SPORT database indicate that prolonged symptom-duration correlates with inferior outcome.
Purpose / Aim of Study: The aim of this study is to evaluate if prolonged symptom-duration is correlated with less favorable outcome following surgery for LDH in a Single- Center Study.
Materials and Methods: 832 patients with first-time LDH were included in a Single-Center Study. Data were prospectively collected in DaneSpine, the Danish National Spine Register. The patient reported outcome measures (PROM) EQ5D, SF36, ODI, VAS-leg and -back were correlated with duration of symptoms.
Findings / Results: 832 patients were included in the study, with complete one-year follow-up on 664 patients (80%) and a reoperation rate of 6%. The duration of symptoms have a negative correlation on all patient related outcome measures.
Conclusions: Delayed surgical intervention results in inferior patient related outcome. Our results indicate that patients operated within the first 3 months of leg-pain achieve best outcome.

119. Does loss of follow-up bias patient-related outcome measures of spine surgery performed at the Sector for Spine Surgery and Research, Region of Southern Denmark.
Karen Højmark , Christian Støttrup, Mikkel Østerheden Andersen
Rygkirugisk sektor, Ortopædkirurgisk afdeling Vejle, Sygehus Lillebælt

Background: DaneSpine, the Danish National Spine Register, collects patient-based pre- and postoperative questionnaires, completed before surgery and at 1, 2, 5 and 10 years postoperatively. The preoperative data entered into DaneSpine are entirely patient-based, and include age, sex, height, weight, duration of back and leg pain on the VAS-scale, SF-36, ODI and EQ-5D. The database was implemented at the Sector for Spine Surgery and Research on June 1st 2010. So far preoperative data has been collected on 99.3% of surgical patients, with a subsequent 1- year follow-up of more than 80%. Loss of follow-up may bias the outcome assessment of clinical registries.
Purpose / Aim of Study: To determine whether patient related outcome measures (PROMs) differed between responders and none-responders.
Materials and Methods: In order to validate DaneSpine data, we have performed 1-year follow-up on non-responding patients for a 3 months consecutive period between 1st of August 2013 until 31st of October 2013. Of the 262 patients operated in the same period 1-year prior, 217 (82,8%) had responded, 3 had died and 10 had received other primary spine surgery and therefore restarted in their registration period. During spring 2014 a structured interview was performed by telephone on the remaining 32 patients, 2 of which could not be reached and 2 did not want to participate.
Findings / Results: We found no difference in PROMs between responders and non-responders at the Sector for Spine Surgery and Research.
Conclusions: A 17% loss of 1-year follow-up does not bias conclusions drawn from PROMs at the Sector for Spine Surgery and Research.