The complex retroperitoneum technically includes anything that is not suspended on a mesentery. To the surgeon, only the genitourinary tract, major vascular structures, and sympathetic chain are generally considered to be retroperitoneal because of the way in which these structures are approached. The pancreas, also a retroperitoneal organ, has been discussed in previous chapters (Chapters 71, 72 and 73).

The general approach to structures in this region involves mobilizing portions of overlying gastrointestinal tract by returning them to their original midline (embryonic) location. The complex anatomy of the underlying structures is first described by presenting the genitourinary tract. Chapters 87 and 88 describe the anatomy of the adrenal (suprarenal) glands through a discussion of adrenalectomy, performed by (open) anterior and posterior approaches and laparoscopically. Chapter 87 also presents some anatomy of the back muscles in the section on the posterior approach to the adrenals. Renal anatomy is described through a discussion of radical nephrectomy (Chapter 89) and renal transplantation (Chapters 90 and 91).