Case report on a rare complication after transanal total mesorectal excision (TaTME) for rectal malignancy vesicorectal fistula

Abstract

Introduction and importance

Transanal Total Mesorectal Excision (TaTME) represents the latest surgical approach in rectal cancer management. We present a rare case of vesicorectal fistula (VRF) following a complication of TaTME surgery.

Case presentation

A 67-year-old male underwent a Hartmann's procedure for perforated rectosigmoid cancer in 2019. He was lost to follow-up and re-presented in 2021 with synchronous cancer of the transverse colon and rectum. A two-team surgical approach was utilized: open subtotal colectomy (transabdominal approach) with concurrent excision of rectal stump (TaTME approach). Intraoperatively, an inadvertent bladder injury was identified and repaired. 8 months later, he re-presented with the passage of urine per rectum. Imaging and endoscopy revealed a VRF with cancer recurrence at the rectal stump.

Clinical discussion

VRF is an uncommon complication of TaTME that carries a significant physical and psychological impact on the patient. While shown to be a safe and useful technique, the long-term oncological outcomes of TaTME are still awaited. Unique complications have been reported with TaTME, including gas embolism and injuries to the genitourinary structures, in which the latter caused the eventual VRF formation in our patient.

Conclusion

Revisional surgery for recurrent disease is challenging and can result in rare complications, especially in patients with distorted anatomy and when new surgical techniques are utilized. Radiotherapy further causes unpredictable tissue healing quality. The challenge remains for proper patient selection with individualization of surgical approaches, while keeping a close eye on the oncological outcomes of the patient.

Highlights

• •Trans anal mesorectal excision is a novel procedure for management of rectal cancers.
• •We report a rare case of vesicorectal fistula (VRF) following a complication of TaTME surgery.
• •Revisional surgery for recurrent disease is challenging and can result in rare complications, especially when new surgical techniques are utilized.
• •As per the available evidence, TaTME provides similar oncological and functional results comparable to the current standards of care.
• •Every new approach and technique has its own pros and cons; constant refinements to achieve standard of care will be the solution in the future.

1. Introduction

Transanal total mesorectal excision (TaTME) represents the latest surgical approach in rectal cancer management. Compared to abdominal TME methods, TaTME has allowed for better visualization in a confined space, with improved specimen quality [1] and preservation of function [2], [3]. TaTME has however shown to be technically challenging. Unfamiliarity of the pelvic anatomy from the transanal viewpoint can predispose to wrong plane dissection, with resultant genitourinary and pelvic nerve injuries. CO₂ embolism has also been reported [4]. With the paucity of literature on its long-term oncological outcomes, concerns about the safety of TaTME have surfaced.

We present a rare case of vesicorectal fistula (VRF) following revisional TaTME surgery for recurrent rectal cancer. We will discuss the postoperative outcomes of TaTME and propose the pathogenesis and management options for VRF.

This case report has been reported in line with the SCARE Criteria [5].

2. Presentation of case

A 65-year-old man with a strong family history of colorectal cancer initially presented with an acute abdomen in 2019. His past medical history included diabetes mellitus, hypertension, and hyperlipidemia controlled on medication. He was diagnosed with peritonitis secondary to a perforated rectosigmoid tumor based on imaging. He underwent emergency exploratory laparotomy with Hartmann's procedure and palliative resection of the perforated colon (Fig. 1). Intraoperative flexible sigmoidoscopy showed polyposis with ulceration along the inspected rectum. The pathology was a stage IIB Pathologic staging (pTNM) (AJCC, 8th Edition): pT4a pN0, moderately differentiated adenocarcinoma of the distal sigmoid colon. The proximal and distal margins were clear of malignancy, though polyps with tubular adenomas with low grade dysplasia changes were seen at both proximal and distal resection margins.

Fig. 1.

Gross specimen of the resected rectosigmoid colon showing multiple polyps.

Attenuated familial adenomatous polyposis (AFAP) was suspected due to the extensive polyposis and strong family history. The patient defaulted follow-up, adjuvant chemotherapy, and a completion scope.

The patient re-presented 18 months later with per rectal bleed and change in bowel habits per stoma. His CEA level was elevated at 17.6 ng/mL. Computed tomography scan of the thorax, abdomen and pelvis (CT TAP) showed findings suspicious of rectal tumor recurrence (Fig. 2a), and a synchronous or metachronous transverse colonic tumor (Fig. 2b). Endoscopic examination confirmed adenocarcinoma on biopsy of both lesions. The preoperative staging of rectal tumor is NCCN stage 3 (based on MRI T3, node positive disease). Following discussion at the multidisciplinary tumor board, neoadjuvant concurrent chemo radiotherapy (CCRT) was recommended. In view of noncompliance with previous treatment, short-course radiation therapy (25 Gray over 5 days) and two cycles of neoadjuvant chemotherapy (XELOX regimen - Capecitabine and Oxaliplatin) were given preoperatively.

Fig. 2.

a. Irregular polypoidal thickening of the rectal stump with mesorectal fat stranding

Fig. 2b. Irregular thickening of the proximal transverse colon with pericolic fat stranding.

Preoperative CT imaging after completion of CCRT showed reduced tumor size and distortion of the pelvic anatomy (Fig. 3). Patient wished to preserve sphincters on discussion (instead of Abdomino-perineal resection) and was hence counselled for subtotal colectomy with ultra-low anterior resection of rectal tumor via TaTME approach.

Fig. 3.

Distorted pelvic anatomy with the bladder and rectal stump in an unusually close proximity.

A two-team surgical approach was utilized: open subtotal colectomy with end ileostomy (transabdominal method) and concurrent rectal stump tumor excision (TaTME approach). With a low rectal tumor extending 2 cm from the anal verge, circumferential rectotomy with adequate margins was done prior to placing the initial oncological purse-string suture. Circumferential dissection was continued up to the level of the pelvic inlet. The abdominal team encountered dense scarring and fibrosis at the TME plane in the pelvis, and limited space in view of the bulky tumor in a male pelvis. Hence further dissection down the TME plane by the abdominal approach was limited.

2 h into the surgery, air was noticed in the urine bag. On reexamination of the surgical dissection planes, an inadvertent bladder injury was identified. The urology team was consulted and flexible cystoscopy was performed. A 2 cm full-thickness injury in the posterior bladder wall was found and noted to be in close proximity with the trigone of the bladder. Contrast flow into ureters was intact with no injuries detected on retrograde pyelogram (Fig. 4a, 4b). The bladder defect was closed in two layers with Vicryl 2–0. After resection of the rectal tumor, the remnant rectal stump just above the anal canal was closed with Prolene 0 and Vicryl 3–0 reinforcements. The transverse colon specimen was a stage IIIB, moderately differentiated mucinous adenocarcinoma. R0 resection was achieved and postoperative CEA levels dropped to 5.9 ng/mL. The rectal stump specimen had shown residual adenocarcinoma features with clear margins and negative lymph node metastasis (R0 resection), though three microscopic tumor deposits (<1 mm size) were seen in the TME fat plane. Urinary catheter was removed on post-operative day 10. The patient made an uneventful recovery and was advised adjuvant chemotherapy in view of the above post-operative pathological staging. Patient subsequently defaulted follow-up and adjuvant chemotherapy.

Fig. 4.

a, 4b. Retrograde pyelogram done intraoperatively, showing a continuous flow of contrast dye into the ureters with no injuries detected.

8 months later, the patient re-presented with the passage of urine per rectum for two weeks duration with nil symptoms before this presentation. There was good urine stream without pneumaturia, fecaluria, or urinary tract infection (UTI). His CEA level had risen to 6.5 ng/mL. Perineal examination showed an irregular lesion along the previous suture line of the remnant rectal stump. CT TAP revealed a 5 cm, ill-defined soft tissue mass in the pre-sacral region, with possible communication with the bladder (Fig. 5).

Fig. 5.

Ill-defined soft tissue mass in pre-sacral region with a small hypodense collection inseparable from the prostate, with possible communication with the bladder.

A small exophytic liver nodule was seen, suggesting rectal cancer recurrence with malignant bladder invasion and liver metastasis. Biopsy of the rectal stump lesion confirmed local recurrence. With suspicions of VRF, retrograde cystogram was done. This revealed intravesical gas and a fistula (VRF) arising from the posterior bladder wall, traversing within the pre-sacral soft tissue, with leakage of contrast into the rectal stump (Fig. 6). The patient was scheduled for urological review and palliative chemotherapy in view of rectal cancer recurrence and metastasis but has since defaulted follow-up.

Fig. 6.

Retrograde cystogram showing intravesical gas and a fistula between the bladder and rectal stump, with leakage of contrast into the rectal stump.

3. Discussion

3.1. Outcomes of TaTME

TaTME represents the latest surgical approach in rectal cancer management to overcome the challenges of open and laparoscopic TME (lap TME), especially in overweight patients and in deep, narrow pelvises [1]. It has 1) improved distal margin visualization; 2) improved pathological specimen quality; 3) reduced positive circumferential resection margins (CRM) rates; 4) reduced frequency of open conversion; and 5) significantly reduced operating time with a two-team approach [1], [6].

Postoperative functional outcomes were found to be comparable if not superior to lapTME, with similar preservation of sexual function and better preservation of urinary function due to improved exposition of hypogastric nerves during TaTME approach [2], [3]. While temporary loss of anal sphincter function is experienced post-TaTME due to intraoperative anal stretch and effacement [2], the impact on the quality of life is largely insignificant as patients with low rectal cancer would typically have a diverting ileostomy.

The reported complications unique to TaTME and paucity of literature on its long-term oncological outcomes have raised concerns of its safety. Interpretation of unfamiliar surgical planes have led to wrong plane dissection, resulting in genitourinary and pelvic nerve injuries [7]. Although rare, CO₂ embolism has also been reported [4].

Published oncological outcomes have been conflicting, with reports from Norway and the Netherlands showing high local recurrence rates and multifocal patterns of recurrence [8], [9]. If the initial purse-string suture is not adequately fastened, tumor cell spillage may occur, with high-flow gas insufflation further conferring the risk of tumor aerosolization and seeding. Studies from expert centers however have reported much more reassuring data [10], demonstrating that oncological safety is not compromised if TaTME is done in expert high-volume centers, where there is consistent supervision and evaluation of oncological outcomes [11].

We encountered a case of VRF following revisional TaTME surgery for recurrent rectal cancer. VRF is rare and its true incidence is not known, but enterovesical fistulae account for only 0.03 % of all surgical admissions [12]. Acquired enterovesical fistulae are frequently caused by inflammatory disease, malignancy, and iatrogenic complications [12].

3.2. Pathogenesis of the VRF

The cause of VRF formation in our patient was multifactorial and includes tumor location, poor disease biology, an iatrogenic intraoperative complication and post-radiation effects, with resultant disruption of tissue planes.

As a revisional surgery, extensive adhesions and fibrosis obscured the tissue planes, making identification of the correct dissection planes particularly challenging. The proximity to the rectal stump further predisposed the bladder to intraoperative injuries. Furthermore, poor tissue quality and impaired tissue healing are known effects of neoadjuvant radiotherapy. Radiation may promote endarteritis obliterans and localized ischemia of the posterior bladder wall, which may cause the tissue to be more friable and prone to fistula formation [12], [13]. In our case, radiation-induced changes in bladder possibly accounted for poor healing, and together with the local recurrence, had contributed to the VRF development.

3.3. Management options for VRF

VRF poses a reconstructive challenge for surgeons, and there is currently no consensus on a gold standard for treating this rare pathology. Surgery is the definitive treatment, although this has been associated with high morbidity and recurrence rates [14]. Patients with un-resectable cancer are instead considered for conservative treatment, which involves urinary diversion via catheterization, suprapubic cystostomy or nephrostomy, or a proximal diverting enterostomy [12].

Surgical management is guided by etiology. For non-malignant fistulae, the involved rectum is resected and the bladder defect is closed, with or without the interposition of vascularized flaps. Techniques include the trans-sphincteric (York-Mason), trans-perineal, transanal, and transabdominal approaches. Minimally invasive techniques such as over-the-scope clip (OTSC) can be used to manage smaller fistulae [15]. Some case reports have also described the use of fibrin glue injection with no post-operative complications, but its efficacy should be further studied [16]. For malignant fistulae, depending on the extent of spread, a radical cystoprostatectomy or pelvic exenteration may be required [17].

4. Conclusion

VRF is a rare condition that carries a significant physical and psychological impact on patients. To our knowledge, this is the first report of a VRF following a complication of TaTME surgery. The risks of encountering rare complications with novel techniques should not be underestimated, especially in revisional surgery for recurrent disease. Anatomical distortion and unpredictable tissue healing quality post-radiotherapy may further complicate an already difficult surgery. The challenge remains for proper patient selection with individualization of surgical approaches, while keeping a close eye on the oncological outcomes of the patient.

As per the available evidence, TaTME provides oncological and functional results comparable to the current standards of care. Every new approach and technique have its own pros and cons. Combinations of techniques and constant refinements to achieve standard of care will be the solution in the future.

Funding

Nil.

Ethical approval

Not applicable as it's a case report, patient consent obtained.

Ethical approval is exempt at our institution.

Author contribution

1] Dr. Sapphire Ho: Original Manuscript.

2] Dr. Kishore Rajaguru: Writing: Review and editing.

3] Dr. Ng Jing Yu: Supervision.

4] Dr. Seow Choon Sheong: Writing: Supervision.

Consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Provenance and peer review

Not commissioned, externally peer-reviewed.

Guarantor

Dr. Kishore Rajaguru.

Declaration of competing interest

Nil.