321 © Springer International Publishing AG 2017 P. Ruggieri et al. (eds.), Tumors of the Sacrum, DOI 10.1007/978-3-319-51202-0_23 M.T. Houdek, M.D. • P.S. Rose, M.D. • F.H. Sim, M.D. (*) Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA e-mail: Houdek.Matthew@mayo.edu; Rose.Peter@mayo.edu; Sim.franklin@mayo.edu S.L. Moran, M.D. Division of Plastic and Reconstructive Surgery, Mayo Clinic, Rochester, MN, USA e-mail: Moran.Steven@mayo.edu M.J. Yaszemski, M.D. Ph.D. Department of Orthopedic Surgery and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA e-mail: Yaszemski.Michael@mayo.edu 23 Sacral Biomechanics and Reconstruction Matthew T. Houdek, Peter S. Rose, Steven L. Moran, Michael J. Yaszemski, and Franklin H. Sim 23.1 Introduction En bloc resection is considered a mainstay of treatment for primary tumors of the sacrum. Based on the extent and location of the tumor, following en bloc resection spinopelvic continuity can be compromised, and as such reconstruction is neces- sary. However, en bloc resection often creates a difficult reconstructive challenge for orthopedic and plastic oncologic and reconstructive surgeons due to the combi- nation of a segmental bony defect and the complex biomechanics of the sacrum. In addition to these significant mechanical issues, the surgical anatomy of the bony, vascular, and visceral pelvic structures contributes to a technically demanding reconstruction. The purpose of this chapter is to describe the biomechanical and technical challenges of reconstruction following sacral resection and the authors’ suggestions to address those challenges.