ABSTRACT
The surgical approach is planned using magnetic resonance imaging. The abdominal approach is performed prior to the perineal approach. Stomas, conduits, and the myocutaneous flap are performed prior to or during the perineal approach. The location of the primary or recurrent tumor determines the operative approach for a perineal or prone dissection. Tumors involving the posterior compartment and the sacrum above the junction of the S3-S4 disc space require a prone abdominosacral excision in most cases (always for lateral combined with posterior compartments). If the tumor is centrally placed on the sacrum, dissection of the upper sacral nerves first (to free them laterally) can allow an anterior central sacral vertebral body excision between the sacral foramina without lateral or prone excision. The anterior compartment excision and planes are best performed radically in modified Lloyd-Davies and can be performed prior to prone positioning for the posterior and lateral completions. This also allows access into the pelvis from the prone position to guide excision of the sacrum radically with identification and preservation of the sciatic nerves. This maneuver of disconnecting the anterior compartment, anterolateral muscles, and ligaments during the abdominal and perineal resections means when prone disconnection of the sacrum is performed, access can be more readily achieved into the pelvis by rotating the transected sacrum caudal to expose the anterior pelvis free of muscular and ligamentous anterior attachments and direct visualization of the preserved lumbosacral trunks.
