Clarke MJ, Zadnik PL, Groves ML, Dasenbrock HH, Sciubba DM, Hsu W, Witham TF, Bydon A, Gokaslan ZL, Wolinsky JP. En bloc hemisacrectomy and internal hemipelvectomy via the posterior approach. J Neurosurg Spine. 2014 Sep; 21(3):458-67.