Guide to Surgical Procedures on Hollow Viscera: Part 2 Colorectal, Ostomy, and Malabsorptive Bariatric Procedures

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1 Integrative Imaging Pictorial Essay Roberts et al. Hollow Viscera Surgery Integrative Imaging Pictorial Essay CME SM Guide to Surgical Procedures on Hollow Viscera Downloaded from by on 04/26/18 from IP address Copyright RRS. For personal use only; all rights reserved FOCUS ON: manda Roberts 1 Randy Fanous 2 Nasir M. Jaffer 2 Robin McLeod 3 Tanya P. Chawla 2 W. Frederick u 2 Sangeet Ghai 2 Roberts, Fanous R, Jaffer MN, et al. Keywords: abdominal imaging, bariatric surgery, colon, hollow viscera, ostomy, rectum DOI: /JR Received July 19, 2011; accepted without revision ugust 8, Department of General Surgery, University of Toronto, 500 University ve, Toronto, ON M5G 1V7, Canada. ddress correspondence to. Roberts (amanda.roberts@utoronto.ca). 2 Department of Medical Imaging, University of Toronto, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada. 3 Department of General Surgery, Mount Sinai Hospital, Toronto, ON, Canada. CME/SM This article is available for CME/SM credit. JR 2012; 199: X/12/ merican Roentgen Ray Society Guide to Surgical Procedures on Hollow Viscera: Part 2 Colorectal, Ostomy, and Malabsorptive ariatric Procedures OJECTIVE. The objective of this article is to explore with a surgical perspective the key radiologic features of common bariatric, colorectal, and ostomy procedures. The images and diagrams show relevant postoperative anatomy. CONCLUSION. n understanding of procedures on the hollow viscera is essential for a radiologist at any level. The ability to quickly recognize postoperative anatomy is critical to accurately and efficiently interpret routine imaging studies and to diagnose postoperative complications. S urgical procedures are performed on hollow viscera from the esophagus to the anus. Understanding the postoperative anatomy of these procedures is increasingly important because a timely diagnosis can affect patient care and outcome. Many patients undergo multiple procedures over a lifetime, making understanding of each procedure crucial. Postoperative evaluation is performed with various imaging modalities. Urgent evaluation is most commonly performed with CT because of accessibility and ease of interpretation. lthough urgent postoperative evaluation with gastrointestinal imaging modalities, such as fluoroscopy, is not common, nonurgent indications for these investigations require that radiologist thoroughly understand the anatomy after gastrointestinal operations because radiologic interpretation can be altered. The purpose of this article is to sequentially explore procedures commonly performed for benign and malignant disease of the intestines. Procedures on the esophagus and stomach and additional bariatric operations are described in Part 1, which also appears in this issue. ariatric Surgery With the ever-growing incidence of obesity around the world, bariatric procedures are becoming an increasingly important aspect of surgical practice. ariatric surgery can induce weight loss by two methods, restriction and malabsorption [1]. Restrictive procedures include laparoscopic adjustable gastric banding and sleeve gastrectomy and are described in Part 1. Malabsorptive procedures include bil- iopancreatic diversion and jejunoileal bypass. Combinations of these procedures include Roux-en-Y gastric bypass and biliopancreatic diversion with duodenal switch [1]. Jejunoileal ypass Jejunoileal bypass (Fig. 1) was performed mainly during the 1950s to 1970s. It was the origin of the malabsorptive bariatric procedures [1]. The procedure involved bypassing most of the small bowel with a short segment ( cm) of jejunum, which was anastomosed to the terminal ileum. This bypass resulted in an unacceptable incidence of malnutrition complications and is therefore no longer performed. Older patients, however, may still have this anatomic configuration [2]. iliopancreatic Diversion The first step in biliopancreatic diversion (Fig. 1) is subtotal gastrectomy, which results in a residual gastric pouch. The terminal ileum is then divided 250 cm proximal to the ileocecal valve [1]. The distal end of the divided terminal ileum is anastomosed to the remnant stomach, and the proximal end is anastomosed to the terminal ileum approximately cm proximal to the ileocecal valve. Prophylactic cholecystectomy can be performed because of the high incidence of gallstones secondary to malabsorption of bile salts. iliopancreatic Diversion With Duodenal Switch or Duodenal Switch lone ecause of the high rate of marginal ulcer associated with biliopancreatic diversion, the duodenal switch procedure (Fig. 1C) was devel- 76 JR:199, July 2012

2 Hollow Viscera Surgery Downloaded from by on 04/26/18 from IP address Copyright RRS. For personal use only; all rights reserved oped to address bile reflux gastritis [1]. Instead of distal gastrectomy, resection of most of the stomach is performed to create a narrow lesser curvature tube analogous to a sleeve gastrectomy. The duodenum is divided to leave approximately 2 cm of intact duodenum beyond the pylorus. circular stapler is used to establish an anastomosis between the stomach with this small portion of duodenum and the distal end of the 250 cm of divided terminal ileum. This difficult anastomosis has a high leak rate. The gastric staple line, duodenal stump, and ileoileostomy are all areas of concern about postoperative anastomotic leak [1]. Ostomy Overview The term ostomy refers to the construction of an artificial opening. n ileostomy is made from the ileal portion of the small bowel and is typically placed in the right lower quadrant of the abdomen [3]. n ostomy derives its name from the portion of the gastrointestinal tract from which it is made. For example, an ostomy or opening made from the jejunum is a jejunostomy, from the stomach is a gastrostomy, and from the large bowel is a colostomy. ecause colostomies are most commonly made from the left side of the colon (descending colon), they are typically located in the left lower quadrant. Ostomies are also established in a location that allows the bowel to pass through the rectus abdominis muscle, decreasing the risk of development of parastomal hernia. Ostomies can be loop or end, depending on the procedure and the indication. Diversion by ostomy can be permanent or temporary. Temporary diversion is used to divert the fecal stream and protect an anastomosis at high risk of leak. high-risk anastomosis may be located in a radiation field or low in the pelvis [3]. permanent ostomy is needed when the anorectum has been removed, as after abdominoperineal resection. Complications Ostomy complications can occur early or late after surgery. Stoma necrosis is an early complication caused by an inadequate blood supply [4]. Mucosal necrosis can cause sloughing of the mucosa but generally has no long-term sequelae and does not require intervention. If full-thickness necrosis (extending below the level of the fascia) has occurred, immediate surgical revision is needed. If necrosis does not extend below the level of the fascia, the patient can be observed, but stenosis will likely occur and require revision at a later date [4, 5]. Sometimes in this situation the stoma separates from the skin and infection develops, requiring earlier surgical intervention. Stoma retraction is usually caused by tension on the bowel during stoma construction [5]. Later, it can be caused by weight gain, development of a parastomal hernia, or recurrence of Crohn disease. Retraction is managed by changing the type of appliance or the method of application. If continued leaking results in poor quality of life and skin irritation or breakdown, revision may be necessary (Figs. 2 and 2). Prolapse occurs when the intestine protrudes excessively through the stoma opening. It is almost always associated with a parastomal hernia and is most common with loop transverse colostomy. Stomal prolapse rarely causes incarceration and strangulation of the bowel. The stoma site usually is changed if excessive prolapse has occurred [4] (Figs. 2 and 2C). Parastomal hernia occurs when weakness in the abdominal wall fascia surrounding the stoma allows protrusion of abdominal cavity contents [5]. Repair is undertaken when the hernia is large, interferes with the stoma appliance, affects stoma function, or is painful. Repair can be achieved by relocation and primary fascial or prosthesis repair. Recurrence rates are very high no matter which technique is used. Obesity is a major risk factor (Fig. 3). End In end ostomy (Fig. 4), the end of the bowel opens at the abdominal wall. End ostomy is more commonly used for permanent diversion than is loop ostomy [3]. Loop loop ostomy (Fig. 5) is constructed by passing a loop of bowel through the abdominal wall. n opening is then made on one side of the bowel wall to create an afferent (proximal) limb and an efferent (distal) limb, resulting in two luminal openings. The bowel contents pass through the afferent limb [3]. Colorectal Procedures Hemicolectomy Right hemicolectomy For disease processes (e.g., malignant lesions and bleeding) in the cecum and ascending colon, a segment of colon from the terminal ileum to the hepatic flexure is removed. This right hemicolectomy (Fig. 6) requires division of the ileocolic and right colic arteries [6]. The right branch of the middle colic artery may also be ligated [6]. Left hemicolectomy For disease processes in the descending colon, a segment of colon from the splenic flexure to the sigmoid colon is removed [4]. This procedure requires division of the left colic artery at the level of the inferior mesenteric artery [7]. variation of vascular division includes dividing the inferior mesenteric artery at its origin with or without division of the left branch of the middle colic arteries [7]. Extended right hemicolectomy For lesions at the hepatic flexure or proximal transverse colon, a segment of colon is removed in a similar manner as for right hemicolectomy. To encompass the lesion, the distal resection margin is extended along the transverse colon, necessitating division of the ileocolic, right colic, and middle colic arteries [8]. Extended left hemicolectomy For lesions at the splenic flexure, a segment of colon is removed in a similar manner as for left hemicolectomy [4]. To encompass the lesion, the proximal resection margin is extended along the transverse colon, necessitating division of the middle colic, left colic, and proximal sigmoid arteries at their independent origins or ligation of the inferior mesenteric artery at its origin [7]. Subtotal Colectomy Subtotal colectomy (Fig. 7) involves removing the colon from the terminal ileum to the rectum [8]. If intestinal continuity is not immediately restored, a permanent or temporary end ileostomy is made, and the rectal stump is left in place. Subtotal colectomy is indicated for ulcerative colitis (alone or as part of an ileal pouch anal anastomosis), fulminant infectious colitis, synchronous malignant tumors, hereditary nonpolyposis colorectal cancer, and occasionally, severely obstructing sigmoid cancer [8]. Ileocolic Resection Ileocolic resection involves removal of the distal ileum with the cecum [4]. Intestinal continuity is established immediately by means of a primary anastomosis between the ileum and ascending colon [8]. This procedure is most commonly performed in the care of patients with Crohn disease. nterior Resection To complete an anterior resection (Fig. 8), a segment of colon from the sigmoid to the upper rectum is removed [8]. Low anterior resection involves a similar resection, but the rectum is removed below the peritoneal reflection. The levator muscles and anal sphincter are preserved. This resection requires division of the inferior mesenteric artery [4]. Low anterior JR:199, July

3 Roberts et al. Downloaded from by on 04/26/18 from IP address Copyright RRS. For personal use only; all rights reserved resection is most commonly indicated for malignant lesions in the proximal two thirds of the rectum. Intestinal continuity can be restored immediately or later with a coloanal-colorectal anastomosis or a colonic J pouch [8]. Hartmann Procedure In a Hartmann procedure (Figs. 9 and 10), the sigmoid colon is removed, a rectal stump is left in place, and an end colostomy is established [4]. This procedure is indicated in the management of complicated diverticular disease, particularly in the acute phase [8]. In the management of nonmalignant disease (e.g., diverticular disease), the vascular mesentery can be divided close to the colon. owel continuity can be reestablished at a later date, once the inflammatory changes have resolved. bdominoperineal Resection For malignant lesions in the distal third of the rectum or the anus, abdominoperineal resection (Fig. 11) is performed to remove a segment of colon from the sigmoid to the anus and establish a permanent end colostomy [8]. The dissection requires an abdominal and a perineal component. The perineal dissection requires that the anus be removed with the specimen. The perineum is closed without an anal opening, and intestinal diversion is through the colostomy. Total Proctocolectomy Total proctocolectomy (Fig. 12) entails removal of the entire colon from the terminal ileum to the anus. Only an anal cuff is left in place, and a permanent end ileostomy is established, unless an ileal pouch anal anastomosis procedure has been performed [8]. Total proctocolectomy with end ileostomy is ideal for patients with poor anal sphincter function or incontinence. It also can be performed to treat ulcerative colitis. Ileal Pouch nal nastomosis Ileal pouch anal anastomosis (Fig. 13) entails removal of the entire colon and restoration of intestinal continuity with a pelvic pouch reservoir made from small bowel [8]. Postoperative evaluation can be completed with a fluoroscopic pouchogram to ensure the absence of leakage before ileostomy reversal [8]. Ileal pouch anal anastomosis is performed in the care of patients with ulcerative colitis or familial adenomatous polyposis and occasionally those with Crohn colitis. n ileal pouch anal anastomosis allows bowel movements per rectum; a permanent stoma is avoided. The procedure can be completed in one, two, or three stages. Three stages The first stage of the threestage ileal pouch anal anastomosis procedure is subtotal colectomy and construction of an end ileostomy. This operation leaves a rectal stump similar to that in a Hartmann procedure [8]. The subtotal colectomy is usually performed as the first step in acutely ill patients, avoiding low pelvic dissection, or when the diagnosis of Crohn disease versus ulcerative colitis is unclear. In the second operation, a pelvic pouch is constructed, and a protecting loop ileostomy is established. The pelvic pouch is most commonly a J pouch but can be an S or W pouch [4]. The third operation is reversal of the loop ileostomy. Two stages The first operation in twostage ileal pouch anal anastomosis is total proctocolectomy and establishment of a pelvic pouch and loop ileostomy [5]. The second procedure is reversal of the loop ileostomy. One stage During one-stage ileal pouch anal anastomosis, total proctocolectomy is performed and an ileoanal pelvic pouch is constructed. No protecting loop ileostomy is used [8]. Complications of ileal pouch anal anastomosis Complications after ileal pouch anal anastomosis can occur early or late postoperatively. The most common early complication requiring radiologic evaluation is an anastomotic leak [9]. nastomotic leaks can occur at one or more of three possible sites the blind end of the ileal stump, the anastomosis between the pouch and the anus, and the parallel staple lines along the sides of the pouch [10]. Leaks can be identified with fluoroscopic pouchography or CT with transrectal injection of water-soluble contrast material. n anastomotic leak can cause pelvic abscesses that may require interventional drainage. Pouch leak and abscess formation can cause pelvic sepsis and pouch failure [9, 10]. Late complications of ileal pouch anal anastomosis include pouchitis, fistulas, and strictures [9]. Pouchitis, or inflammation of the ileal pouch, is the most common complication [9, 10]. The diagnosis is typically based on clinical findings with the aid of endoscopic evaluation [10]. If imaging is performed because leak or abscess is suspected because the patient has symptoms of pouchitis, CT or MRI can depict features consistent with pouchitis, such as pouch thickening, inflammatory changes, peripouch adenopathy, mucosal enhancement, and pouch dilatation [10]. Persistent anastomotic leak and recurrent Crohn disease can lead to fistula formation between adjacent bowel and the abdominal wall, anal sphincter, and genitourinary tract, and these epithelialized tracks are best identified with MRI. nastomotic strictures can occur after ileal pouch anal anastomosis and if severe can result in pouch outlet obstruction or smallbowel obstruction [9]. Obstruction secondary to stricture can be evaluated with CT or a barium enema examination [10]. cknowledgment We thank Julie Roberts for the medical illustrations in this article. Conclusion Using the descriptions, diagrams, and images in this article, practicing and in-training radiologists should be able to identify the relevant anatomic findings after intestinal and malabsorptive bariatric surgical procedures. This knowledge should aid in accurate and timely radiologic diagnosis. References 1. Schirmer, Schauer PR. The surgical management of obesity. In: runicardi FC, ndersen DK, illiar TR, et al. Schwartz s principles of surgery, 9th ed. New York, NY: McGraw-Hill, Chandler RC, Srinivas G, Chintapalli KN, Schwesinger WH, Prasad SR. Imaging in bariatric surgery: a guide to postsurgical anatomy and common complications. JR 2008; 190: eck DE, Roberts PL, Rombeau J, Stamos MJ, Wexner SD. Intestinal stomas. In: Wexner SD, Stamos MJ, Rombeau J, Roberts PJ, eck DE. The SCRS manual of colon and rectal surgery. New York, NY: Springer-Verlag, 2009: Dunn KM, Rothenberger D. Colon, rectum, and anus. In: runicardi FC, ndersen DK, illiar TR, et al. Schwartz s principles of surgery, 9th ed. New York, NY: McGraw-Hill, Shellito PC. Complications of abdominal stoma surgery. Dis Colon Rectum 1998; 41: Scott-Conner CE, ed. Chassin s operative strategy in colon and rectal surgery. New York, NY: Springer-Verlag, 2006:25 41, Senagore, Fry R. Surgical management of colon cancer. In: Wexner SD, Stamos MJ, Rombeau J, Roberts PJ, eck DE. The SCRS manual of colon and rectal surgery. New York, NY: Springer- Verlag, 2009: Mahmoud N, Rombeau J, Ross H, Fry R. Colon and rectum. In: Townsend CM, ed. Sabiston textbook of surgery: the biological basis of modern surgical practice, 17th ed. Philadelphia, P: Saunders Elsevier, 2004: Gorgun E, Remzi FH. Complications of ileoanal pouches. Clin Colon Rectal Surg 2004; 17: roder JC, Tkacz JN, nderson SW, Soto J, Gupta. Ileal pouch-anal anastomosis surgery: imaging and intervention for post-operative complications. RadioGraphics 2010; 30: JR:199, July 2012

4 Hollow Viscera Surgery Downloaded from by on 04/26/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig. 1 Diagrams of bariatric procedures., Jejunoileal bypass., iliopancreatic diversion. C, iliopancreatic diversion with duodenal switch. Fig. 2 Diagrams of stoma complications., End ileostomy., Retraction of stoma. C, Prolapse of stoma. C C JR:199, July

5 Roberts et al. Downloaded from by on 04/26/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig. 3 Right lower quadrant ileostomy complicated by obstructed strangulated parastomal hernia. and, xial CT images show herniation of proximal loop of bowel more proximally into stoma site (asterisks). Loops of bowel (solid arrows) proximal to incarcerated loop are dilated, but ileostomy loop (dashed arrows, ) is decompressed, suggestive of obstruction. Fig. 4 End ostomy., Diagram shows construction of end ostomy., xial contrast-enhanced CT image shows left lower quadrant end colostomy (arrow). Fig. 5 Loop ostomy., Diagram shows afferent (a) and efferent (e) luminal openings., Coronal contrast-enhanced CT image shows afferent (a) and efferent (e) ostomy loops (arrows) where they pass through abdominal wall. 80 JR:199, July 2012

6 Hollow Viscera Surgery Downloaded from by on 04/26/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig. 6 Right hemicolectomy., Diagram shows resection margins at distal ileum and hepatic flexure., Diagram shows right upper quadrant anastomosis between ileum and hepatic flexure of colon. C, Coronal contrast-enhanced CT image shows right upper quadrant anastomosis (circle). Fig. 7 Subtotal colectomy., Diagram shows proximal resection margin in terminal ileum and distal resection margin in rectum., Postresection anatomic diagram shows end ileostomy in right lower quadrant and rectal stump. C JR:199, July

7 Roberts et al. Fig. 8 Low anterior resection., Diagram shows proximal resection margin in sigmoid and distal resection margin in distal rectum., Diagram shows postresection intestinal continuity established with coloanal-colorectal anastomosis. Downloaded from by on 04/26/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig. 9 Diagrams of Hartmann procedure., Resection margins in sigmoid colon., Postresection end colostomy in left lower quadrant and rectal stump. C, Restoration of intestinal continuity by reversal of Hartmann procedure. nastomosis is between sigmoid and rectum. C 82 JR:199, July 2012

8 Hollow Viscera Surgery Fig. 10 Hartmann procedure., xial contrast-enhanced CT image shows staple line of rectal stump (arrow)., xial contrast-enhanced CT image shows remainder of rectal stump (arrow) as it passes into pelvis. Downloaded from by on 04/26/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig. 11 bdominoperineal resection., Diagram shows proximal resection margin in sigmoid. Entire rectum and anus are removed with specimen., Postresection anatomic diagram shows end colostomy. Perineum is closed. Fig. 12 Total proctocolectomy., Diagram shows proximal resection margin in terminal ileum and distal resection margin at anus. nal cuff is left in place., Postresection anatomic diagram shows end ileostomy in right lower quadrant (anal cuff not shown). JR:199, July

9 Roberts et al. Fig. 13 Ileal pouch anal anastomosis., Diagram shows J-shaped pelvic pouch reservoir made from afferent (a) and blind (b) limb of small bowel. Loop ileostomy is closed in second procedure., xial contrast-enhanced CT image shows J pouch in pelvis and blind (b) and afferent (a) limbs. Downloaded from by on 04/26/18 from IP address Copyright RRS. For personal use only; all rights reserved FOR YOUR INFORMTION This article is part of a self-assessment module (SM). Please also refer to Guide to Surgical Procedures on Hollow Viscera: Part 1 Esophageal, Gastric, and Restrictive ariatric Procedures, which can be found on page 66. Each SM is composed of two journal articles along with questions, solutions, and references, which can be found online. You can access the two articles at and the questions and solutions that comprise the Self-ssessment Module by logging on to clicking on JR (in the blue Publications box), clicking on the name, and adding the article to the cart and proceeding through the checkout process. The merican Roentgen Ray Society is pleased to present these SMs as part of its commitment to lifelong learning for radiologists. Continuing medical education (CME) and SM credits are available in each issue of the JR and are free to RRS members. Not a member? Call (from the U.S. or Canada) or to speak to an RRS membership specialist and begin enjoying the benefits of RRS membership today! 84 JR:199, July 2012