Excision of the rectum via a combined abdominal and perineal approach (i.e., an abdominoperineal resection [APR]) has been a time-honored technique for the management of rectal cancer and inflammatory bowel disease (IBD). However, achieving prompt and satisfactory healing of the perineum after such an approach is still a challenge. A wound that has not healed by 6 months after the surgery is considered an unhealed perineal wound (UPW), even though many such wounds will eventually heal by 1 year. The rate of failed perineal wound healing varies greatly in the literature; however, a reasonable estimate suggests that it occurs 20% to 30% of the time. Despite changes in practice that have minimized the number of patients undergoing an APR, some circumstances may lead to this operation secondarily.
Special Situations Leading to an Unhealed Perineal Wound
Failed restorative proctectomy: The focus on sphincter-preserving approaches for both anorectal cancer and IBD has decreased the attention given to the UPW or persistent perineal sinus. However, sometimes complications of these sphincter-saving procedures may require a subsequent proctectomy. At this time, avoiding the morbidity of an unhealed perineal wound may be more difficult.
Failed ileal-anal pouch: Although ileal pouch–anal anastomosis has largely replaced total proctocolectomy with ileostomy as the surgical treatment for ulcerative colitis, pouch failure occurs in approximately 5% to 10% of cases and sometimes requires abdominoperineal excision of the pelvic pouch. Pouch excision has been associated with a risk for UPW of 40% and 10% at 6 and 12 months, respectively.
Recurrent anal and rectal cancer: Combined modality chemoradiation has supplanted surgery as the primary treatment for squamous cell carcinoma of the anal canal, yet when recurrent disease is diagnosed, salvage APR is generally performed in an irradiated field. Similarly, recurrent rectal cancer after low anterior resection may be approached with aggressive multivisceral resections including proctectomy, often combined with preoperative and/or intraoperative radiation. Challenges of reconstruction in these circumstances may be formidable and lead to considerable morbidity.
APR is likely to be a continuing problem facing colorectal surgeons. Prevention and management of this complication continue to be important topics and are the subjects of this chapter.
Technical, patient-related, or disease-related factors may lead to a failure of perineal wounds to heal.
After the rectum is excised, a large pelvic cavity is created, and filling this space with healthy, well-vascularized soft tissue is important in promoting primary healing. Posterior migration of the remaining genitourinary structures and descent of the peritoneal floor help diminish this cavity, but the bony walls laterally and posteriorly tend to prevent it from closing completely.
Excessive bleeding with formation of a hematoma adversely affects postoperative healing, especially if contamination with stool occurs. The resulting pelvic collection may result in a rigid, fibrotic cavity that will heal very slowly if at all. Nonabsorbable sutures may serve as foreign bodies and impair long-term healing.
Malnutrition, diabetes, or obesity may contribute to poor healing, and the underlying indication for proctectomy also clearly affects the likelihood of an unhealed perineal wound. UPW is most likely to occur after a proctectomy for Crohn disease or in the setting of intraoperative radiation and neoadjuvant radiation, whereas patients undergoing a proctectomy for ulcerative colitis or rectal cancer typically have much lower rates of perineal wound breakdown.
Patients with Crohn disease are particularly prone to UPW after proctectomy for several reasons. Crohn disease may be present in the perineal skin itself, which leads to failure of healing at the skin level. In addition, considerable perirectal fibrosis is often present as a result of transmural inflammation and/or fistulization, making a proctectomy technically more difficult and predisposing to inadvertent rectal perforation or residual rectal mucosa, both of which are triggers for a UPW. Chronic use of immunomodulators and/or biologic agents, protein-calorie malnutrition, inadequately controlled systemic inflammation, and local sepsis are also factors predisposing to poor wound healing.
In many studies, pelvic irradiation appears to increase the risk of UPW, presumably because of the ischemia and fibrosis that follow its use. The risks associated with radiation may be exacerbated by concomitant chemotherapy.
Prior to performing a proctectomy, nutritional status and glucose control should be optimized, the patient who smokes should be encouraged to stop smoking, and steroid, biologic agent, and immunomodulator usage should be planned to cover the surgery while minimizing risk.
Perianal sepsis has been associated with poor perineal wound healing after proctectomy, particularly in patients with a “watering can” perineum. In one study of such patients, the rate of UPW was 46%, and other investigators have reported higher rates. The best approach to patients with symptomatic perianal Crohn disease remains controversial. Options include preliminary examination after induction of anesthesia with debridement, drainage of abscesses, and placement of setons ( Fig. 41-1 ), fecal diversion with a loop ileostomy, or an initial subtotal colectomy with an ileostomy. A near-total proctocolectomy with an ultra-low Hartmann pouch can excise almost all the rectum and avoid a perineal wound. If “perineal Crohn disease” is present, biologic agents are likely to improve the tissues and reduce the risks of chronic wounds. They may need to be continued postoperatively.