1. Vertebral Arthrodesis: Revision Rates and Risk Factors in Deformity and Non-Deformity Related Pathologies Banfi G, Zagra A, Lamartina C, Brayda M, Zacchetti S, Viganò M, Berjano P IRCCS Istituto Ortopedico Galeazzi Milan (I)

3. Riccardo Galeazzi (1866- 1952) Chair of Orthopedics in University of Milan for 35 years Studied CHD, scoliosis, Scheuermann’s kyphosis, bone TB, achondroplasia 1939, described the radius fracture-dislocation (Galeazzi’s) Director or “Archivio di Ortopedia” for 35 years

4. Spine fusion Over a decade +220% increase of procedures (USA 1991-2000) Increasing number of revision cases Revision rate 3% - 45%

5. Institution’s case load 2007 to 2011 Non-cervical fusions in Italy: 55,313 Non-cervical fusions in Galeazzi: 2,970 (5.3%)

6. Aim of the study To describe the mid-term revision rate in our Institution To analyze the distribution by age and diagnosis

7. Methods Retrospective review of administrative database 2007-2011

8. Administrative database2007-2011 ICD-9-CM 81.05, 81.07, 81.08 4041 Met inclusion criteria 3082 –Absence of cancer etiology –Non-cervical arthrodesis –First posterior approach Non-revised patients with codes matching revision surgeries 2402 Minimum Follow-up 2 years (2-7); average 4.2 years

9. Diagnosis

10. Revision rates after spinal fusion *p<0.05, **p<0.01, ***p<0.001 in comparison with All Patients; £££ p<0.001 in comparison with scoliosis group, late onset $ p<0.05 in comparison with hyperkyphosis group late onset.

11. Age and Revision *p <0.05, ***p<0.001

12. Results

13. Main Reasons for Revision Sagittal imbalance18.6% Implant mobilization 17.4% Malpositioning 17.4%

14. Causes of revision Sag Imb Imp Mob Pers Symp ns

17. Discussion Overall mid-term revision rate is low (3,6%) compared with the literature (9-45%) High-volume effect? Some causes can be modified: – Implant malpositioning – Insufficient correction in sagittal imbalance

18. Limits Only revisions made at our institution have been included – Revision in other institutions is unlikely for complex cases Late revisions are not included – Late revision is less dependent of surgical appropriateness and quality

19. Conclusions Mid-term revision rate in a high-volume center is low Specific pathologies have higher revision rate Some causes of revision can be corrected

20. Vertebral Arthrodesis: Revision Rates and Risk Factors in Deformity and Non-Deformity Related Pathologies Banfi G, Zagra A, Lamartina C, Brayda M, Zacchetti S, Viganò M, Berjano P IRCCS Istituto Ortopedico Galeazzi Milan (I)