The main principle of incision and drainage of perianal disease is to make adequate elimination of septic conditions and to avoid sphincter damage. It is used in the acute phase and when treatment is needed immediately. Combined surgical treatments with broad-spectrum antibiotics are recommended (Fig. 14.15).

Acute and painless anal fissures are responsive to conservative therapy, which is known to be effective in the majority of patients. However, if the patients have pain due to the fissure itself, without macroscopically rectal inflammation, a lateral internal sphincterotomy can be indicated [31]. The incision of this procedure is made across the intersphincteric groove with separation of the internal sphincter from the anal mucosa (Fig. 14.16).

The surgical management of perianal fistulas in patients with Crohn’s disease is decided by the presence or absence of inflammatory change of the rectum and the type and location of the fistulas. Perianal fistulas can be classified as superficial, intersphincteric, trans-sphincteric, supra-sphincteric, and extra-sphincteric fistula by Park’s anatomical classification, which regards the external anal sphincter as the central reference point [26] (Fig. 14.17). The disease activity and severity of perianal Crohn’s disease can be assessed by the Perianal Crohn’s Disease Activity Index (PCDAI) [16] (Table 14.2).

A simple fistula is a low superficial type such as low inter- or intra-sphincteric lesions with a single external opening, which are not connected to adjacent organs such as the vagina or bladder. A complex fistula is a high type as high inter- or intra-sphincteric, supra-sphincteric, and extra-sphincteric lesions, which have several external openings [37]. Patients who have low fistulas may be treated by a one- or two-stage fistulotomy (Fig. 14.18).

The seton procedure is a surgical technique for Crohn’s fistula to maintain proper pus drainage continuously and to avoid perianal abscess formation by using a seton drain. There are two kinds of seton procedures: the noncutting (loose) seton (Fig. 14.19) and the cutting seton (Fig. 14.20). The noncutting seton procedure is performed by a drain insertion through the fistula tract. According to the noncutting seton procedure, the drain is threaded into the cutaneous opening of a perianal fistula across the mucosal orifice of the fistula tract in the rectum. Then after the drain moves to the anal canal, the two ends of the drain are loosely tied. The cutting seton procedure is performed by tying the ends of the noncutting seton tightly, which can result in a slow fistulotomy by pressure necrosis [31].

High fistulas have a higher incidence of incontinence and recurrence of fistulas. Therefore, a technique to fulfill the fistula tract by using an endorectal mucosal flap was developed (Fig. 14.21). The advantages of endorectal advancement flaps are that the open wounds are avoided and several problems are prevented by dividing the sphincteric strictures, which can cause incontinence after surgery.

Fibrin glue has been used as a sphincter-preserving approach for anal fistulas. This technique begins by evaluating internal and external fistulous openings. After tracing the fistula tract, instilled fibrin glue is filled into the tract [10]. The efficacy is still controversial due to the different results according to the fistula types.

Autologous adipose-derived stem cell transplantation in patients with refractory Crohn’s disease has been developed since Crohn’s disease is an immunologically mediated inflammatory disease. This procedure is delivered by injection of adipose-derived stem cells around the fistula opening and directly into the fistula tract.

The indications for elective surgery in patients with UC are (1) failure of medical management to control symptoms, (2) complications associated with side effects of medications, (3) stricture formation, (4) epithelial dysplasia, dysplasia-associated lesion or mass or malignancy, (5) uncontrollable extraintestinal manifestations of UC, and (6) growth retardation in children [96]. TPC with a Brooke ileostomy is a safe and feasible surgical option in terms of not only postoperative surgical complications but also postoperative quality of life [48].

The procedure of the TPC contains the right hemicolectomy, transverse colectomy, left hemicolectomy, anterior resection, and low anterior resection, which removes the whole rectum to the dentate line. A characteristic of the Brooke ileostomy is primary maturation of the ileostomy. Primary maturation protects the serositis of the exposed ileum and facilitates healing of the ileostomy. The site of the ileostomy is in the right lower quadrant of the abdomen and the lateral one third of the rectus abdominis muscle. The skin around the ileostomy should be flat, and there must be no scars. Secure attachment of an ostomy plate is very important to maintain the quality of life of a patient with an ileostomy or a colostomy (Fig. 14.22).

Complications can occur including wound infection or dehiscence, intraluminal or extraluminal bleeding, intestinal obstruction, intra-abdominal infection or abscess, and other medically related postoperative complications such as pneumonia and pulmonary and cardiovascular diseases. Postoperative sexual and voiding dysfunctions are complications after a proctectomy. Permanent retrograde ejaculation or impotence in male and dyspareunia in female can occur as a result of nerve injuries with proctectomy. The superior hypogastric nerve, inferior hypogastric nerve, and both lateral pelvic plexuses should be well preserved to protect postoperative sexual and voiding dysfunctions [51, 73, 85]. Complications related to an ileostomy are ileal necrosis and parastomal skin irritation, stenosis, hernia, and prolapse [49]. A common cause of ileal necrosis is torsion of the mesentery. If ileal necrosis occurs, resection and a new ileostomy formation are necessary.

This procedure is performed electively and contraindicated in an emergency situation and attractive surgical option in terms of complete removal of the whole colorectal mucosa and preservation of the defecation function. TPC with IPAA is also indicated in familial adenomatous polyposis. However, Crohn’s disease is a contraindication due to remarkable postoperative complications and poor long-term outcomes [77, 79].