Postoperative Imaging Findings of Colorectal Surgery: A Pictorial Essay

Figures

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  Fig. 1. Anatomic schematic diagram of colon surgery. A. Ileocecal resection. Terminal ileum, ileocolic valve and cecum are resected, and ileocolic vessels are also ligated. B. Right hemicolectomy. Right colon is resected, and ileocolic vessels, right colic vessels, and right branch of middle colic vessels are ligated. C. Extended right hemicolectomy. It includes ligation of the middle colic vessels at their base. D. Transverse colectomy. Transverse colon is resected, and middle colic vessels are ligated. E. Left hemicolectomy. Left colon is resected, and left branches of middle colic vessels, left colic vessels and first braches of sigmoid vessels are ligated. F. Extended left hemicolectomy. It includes ligation of the right branches of the middle colic vessels. G. Anterior resection (low ligation). Distal sigmoid colon and upper rectum are resected. Divisions of the inferior mesenteric artery is ligated, but left colic artery is preserved. H. Anterior resection (high ligation). It includes ligation of the inferior mesenteric artery at its origin. I. Subtotal colectomy. It involves resection of the entire colon excluding the sigmoid colon. Ileocolic vessels, right colic vessels, middle…

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  Fig. 2. Anatomic schematic diagram of rectal surgery. A. Abdominoperineal resection. In this procedure, distal colon, rectum, anal canal and anus are removed, and permanent colostomy is created. B, C. Low anterior resection (B: low ligation, C: high ligation). Unlike abdominoperineal resection, anal canal and anus are preserved. Note the difference in the location of ligation of the inferior mesenteric artery between the two surgical methods.

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  Fig. 3. Subtype of abdominoperineal resection. A, B. Unlike classical abdominoperineal resection (A), extralevator abdominoperineal resection (B) aims to achieve complete excision of the levator ani muscle surrounding the mesorectum adjacent to the cancer.

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  Fig. 4. Subtype of low anterior resection. A, B. Low anterior resection (A) is performed for cancer located in upper-middle rectum. Generally, it is performed when the cancer is situated more than 5 cm away from the dentate line. In contrast, ultralow anterior resection (B) is performed for cancer located in the lower rectum, approximately 2 to 5 cm away from the dentate line.

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  Fig. 5. Anatomic schematic diagram of pelvic exenteration. In this procedure, all the pelvic organs are removed. It can be performed when advanced rectal cancer invades adjacent structures such as the prostate, seminal vesicles, and bladder in males, or the uterus and posterior vaginal wall in females.

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  Fig. 6. Abdominal wound dehiscence. On a contrast-enhanced postoperative CT scan performed 7 days after total colectomy for severe slow transit constipation, separation of the abdominal wall and a fluid collection is identified along the midline incision (arrows).

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  Fig. 7. Anastomotic leakage in a 68-year-old male who underwent a right hemicolectomy for cancer of the transverse colon. A, B. On a contrast-enhanced axial CT scan performed 7 days after surgery, a fluid collection and air bubble are identified near the anastomosis site (arrows).

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  Fig. 8. Urologic injury in a 60-year-old male who underwent a right hemicolectomy for recurred liposarcoma of the right colon and double J stent insertion of the right urinary tract. A. A preoperative contrast-enhanced coronal CT scan shows the proximity of the tumor and ureter (arrow). Double J stent insertion of the right urinary tract was planned due to the potential for ureteral injury during right hemicolectomy. Note the heterogeneously enhancing mass involving the right psoas muscle with infiltration of the terminal ileum, cecum, and right transverse abdominalis muscle. B, C. On a postoperative contrast-enhanced coronal and axial CT scan performed 20 days after surgery, there is right hydroureteronephrosis (arrow in B) and abrupt narrowing of the right ureter near the tumor excision site (arrow in C). Note a possible hematoma and fluid collection at the tumor excision site.

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  Fig. 9. Lymphocele in a 68-year-old male who underwent a robotic intersphincteric resection for rectal cancer. On a contrast-enhanced axial CT scan performed 1 year after surgery, there is a cystic lesion at the right lateral pelvic side wall (arrow).

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  Fig. 10. Parastomal hernia in a 65-year-old male who underwent a Hartmann’s operation for a disrupted coloanal anastomosis with necrosis of his distal colon after LAR. On a postoperative contrast-enhanced CT scan performed 19 months after the surgeries, there is protrusion of a loop of jejunum beyond the peritoneum at the previous ileostomy site of the Hartmann’s operation (arrow). It also presents an abscess in the right abdominal wall near the previous ileostomy site of the LAR (dotted arrow). LAR = low anterior resection

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  Fig. 11. Small bowel obstruction due to a parastomal adhesion after low anterior resection and ileostomy. A postoperative CT scan performed 24 days after the LAR shows abrupt narrowing of the ileum near the ileostomy site, diffuse dilatation of the small bowel to more than 2.5 cm in diameter, and air-fluid levels. It also identifies a beak sign (dotted arrow) and adhesive band (arrow) near the transition zone.

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  Fig. 12. Sinus tract in a 56-year-old male who underwent low anterior resection for rectal cancer. A, B. On water-soluble enema X-ray (A) and contrast-enhanced axial CT scans (B) performed 3 years after surgery, direct communication between the sinus cavity and rectal stump is identified. C. On a postoperative T2WI axial MR performed 3 years after surgery, an air-filled cavity (arrow) in the left lateral pelvic wall is identified. D. Contrast-enhanced T1 axial MR shows rim enhancement of the cavity (arrow).