Sacrectomy and Spinopelvic Reconstruction Jason C. Eck, DO, MS,* Michael J. Yaszemski, MD, PhD, †,‡ and Franklin H. Sim, MD † Patients with malignant lumbosacral pelvic lesions present a difficult surgical challenge. Because of the insidious onset of symptoms, lesions are often diagnosed late in their course, and by that time they have attained a large size. Surgical resection is made more difficult by the complex surrounding anatomy and involvement of the sacral nerves respon- sible for bowel, bladder, and sexual function. Spinopelvic reconstruction is often required after resection. This article presents techniques for sacral resection and subsequent spinopelvic reconstruction. Biomechanical studies are summarized on construct stability, and recommendations are made as to when reconstruction is required. The expected bowel and bladder functional outcomes are summarized, based on the level of sacral resection. Semin Spine Surg 21:99-105 © 2009 Elsevier Inc. All rights reserved. KEYWORDS sacrectomy, spinopelvic reconstruction, tumor, chordoma T umors involving the sacrum present a very difficult surgical challenge. These tumors typically have an in- sidious onset that results in a delayed diagnosis. The tu- mors are difficult to identify on examination because they often expand anteriorly into the pelvic cavity. Conse- quently, these tumors can reach a very large size before diagnosis. Although they can generally be palpated on a digital rectal examination, they are most often identified using axial imaging studies. At the time of diagnosis, the tumors often involve much of the sacrum and the sacral plexus nerve roots. As with other musculoskeletal sarcomas, the goals of surgery are to resect the tumor with negative surgical margins while maximizing postoperative function. These goals are much more difficult to achieve when dealing with sacral tumors because of the complex anatomy. Of- ten, some or all sacral nerves must be sacrificed to achieve negative specimen margins. This may lead to either loss or diminished control of bowel and bladder function. When the tumor involves the pelvis, the sacrectomy can be com- bined with either an internal or external hemipelvectomy. These cases require the collaboration of specialists from multiple disciplines, including spine surgery, orthopedic oncology, colorectal surgery, urology, vascular surgery, plastic surgery, anatomic pathology, radiology, critical care anesthesiology, and medical and radiation oncology. Physiological Consequences of Sacrectomy An important consideration during surgical treatment of sa- cral tumors is the involvement of the sacral nerves. In most cases, sacrectomy involves sacrificing some of the sacral nerves to obtain negative surgical margins. The nerve supply of the bowel and bladder originates from the autonomic and somatic systems. The autonomic innervation comes from the hypogastric plexus and travels through the S2-S4 sacral nerves. The somatic innervation comes from the pudendal nerve that originates from S2 and S3 sacral nerves. The sym- pathetic system acts to constrict the internal anal sphincter and internal urethral orifice. The somatic system acts to con- tract the rectum and bladder. 1 Gunterberg et al 2,3 reported that unilateral resection of the sacral nerves did not affect bowel and bladder function. Bi- lateral resection of the S3 and S4 roots did result in bowel and bladder dysfunction, but the levels responsible were not de- termined. The sexual function response was similar in that unilateral resection of the S2, S3, and S4 roots resulted in retained sexual function but brought about numbness on the side of the resection. 4 Todd et al 5 performed a retrospective review of 53 patients undergoing partial or total sacrectomy to determine the effect of osteotomy level on postoperative bowel and bladder func- tion. Only patients with normal preoperative bowel and bladder function were included in the analysis. The results *Department of Orthopedics and Physical Rehabilitation, University of Mas- sachusetts, Worcester, MA. †Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN. ‡Department of Biomedical Engineering, Mayo Clinic, Rochester, MN. Address reprint requests to Jason C. Eck, DO, MS, Department of Orthopedics and Physical Rehabilitation, University of Massachusetts, 119 Belmont St., Worcester, MA 01605. E-mail: Jason.Eck@umassmemorial.org 99 1040-7383/09/$-see front matter © 2009 Elsevier Inc. All rights reserved. doi:10.1053/j.semss.2009.03.009