Anatomic characteristics make en bloc sacral resections with wide surgical margins a very demanding and challenging procedure in most malignant tumours of the sacrum. Sacral tumours generally respect the nerve sheaths and do not penetrate through them. Instead, they surround the sacral nerves during the growing stages, making it practically impossible to dissect them from the nerves. Ventrally, the tumours also push into the presacral connective tissue layers though they seldom infiltrate the rectum.