If the fistula is small, the diagnosis may be delayed and the patient will present with recurrent urinary tract infections [9].

All the patients must undertake a complete physical examination as part of the diagnostic process with identification of previous incisions, medications, immunosuppression, nutritional status, and comorbidities. The history of relevant coexisting disorders such as diverticular disease, inflammatory bowel disease, pelvic malignancies, and operations is important [1, 7].

The diagnosis is suggested by clinical features like recurrent cystitis, pneumaturia, fecaluria, and urine leakage per rectum. Sometimes, gastrointestinal symptoms such as abdominal pain and diarrhea, are associated.

Identification of the exact site of the fistula is critical for the operative plan.

Cystourethrography, colonoscopy, endoscopic ultrasound (EUS), pelvic magnetic resonance imaging (MRI), and intravenous pyelography are usually used during the RUF workup. Cystoscopy is the reference standard for the diagnosis, with a sensitivity of 80–100 % [7] helping to rule out a uretheral stricture, if present. Colonoscopy is used to assess vascularity and pliability of tissues and to localize the rectal fistula orifice (whenever it is possible).

Both EUS and MRI have shown to be more accurate than computer tomography and are the diagnostic imaging techniques of choice for the assessment of the perianal tract [10].

According to Buchanan [11], surgery guided by MRI reduces further recurrence of fistula by 75 % and should be done in all patients with recurrent fistula.

The preoperative management must also include bowel preparation and antibiotic prophylaxis administered before the operation.

Symptoms of retrorectal tumors are often nonspecific and are related to the location and size of the lesion. Most benign lesions are asymptomatic. Pain or constipation occurs occasionally and are more often related to the presence of large masses (cystic or solid). A careful rectal examination is essential to establish the diagnosis in >90 % of the patients [12, 13]. Most lesions are soft and easily missed if the physician does not maintain a high index of suspicion [14, 15].

Flexible colonoscopy is useful for detecting the involvement of rectal mucosa and may help confirm the level of proximal extension of the tumor [14].

Glasgow et al. reported that transrectal ultrasonography (TRUS) , combined with proctoscopy, had a sensitivity of 100 % and provided information on the size, consistency of the mass, and evidence of local invasion [16].

Computed tomographic scan has been used extensively (Fig. 14.1), is able to distinguish a cystic lesion from a solid lesion, and to reveal sacral involvement or invasion of adjacent structures. MRI is particularly useful in delineating soft tissue planes and evaluating the presence or absence of bony invasion and nerve involvement.

The role of biopsy is controversial [8]. As cases of contamination and tumor spread have been reported, biopsy is usually not indicated, and surgical resection is the best diagnostic option. A biopsy should be performed when the lesion appears to be unresectable and if a tissue diagnosis is required to guide adjuvant therapy (imaging suspicious of Ewing sarcoma, osteogenic sarcoma, neurofibrosarcomas, and desmoid tumors) [17].

The patient is positioned in the prone jackknife position and the perineal area is draped in a sterile fashion. After placing a LoneStar (TM) retractor ^® (Lone Star Retractor System, Cooper Surgical) to dilate the anus, the transanal dissection has begun starting about 1 cm distal to the level of the fistula in the intersphincteric plane. The area around the fistula is dissected and debrided to achieve an adequate view of the opening of the fistula, afterwards the urethral opening is approximated with 4/0 vicryl interrupted sutures.

The patient is therefore repositioned in a modified lithotomy position. Draping and pneumoperitoneum are obtained in the usual fashion. After positioning a total of six ports, the laparoscopic part of the procedure is started. Using a medial-to-lateral approach, the descending and sigmoid colon are mobilized. The inferior mesenteric vein and superior rectal artery were identified (Fig. 14.2), skeletonized and divided between Hem-o-lok clips (Weck Teleflex Medical), after identifying and preserving the left ureter and gonadal vessels. Then, the entire descending and sigmoid colon were medialized above Toldt’s fascia.

At this point, the four-arm da Vinci ^® Si HD robot (Intuitive Surgical, Inc., Sunnyvale, CA, USA) is docked over the left hip. Total mesorectal dissection and autonomic nerve preservation is carried out posteriorly, laterally, and finally anteriorly (Fig. 14.3). The dissection of the rectum is continued all the way down until the transanal intersphincteric plane is met, freeing the distal rectum from its attachments around the anal hiatus. The port sites were closed.

The patient is repositioned in the prone jackknife position. The perineal area is draped in a sterile fashion. A wound protector was introduced through the anus enabling the specimen extraction (Figs. 14.4 and 14.5). After the segmental resection of the diseased rectum and a handsewn rectoanal anastomosis (Fig. 14.6), a Penrose drain was left in between the anastomotic sutures, draining the pelvic cavity.