**6. Complications management**

#### **6.1 Intraoperative complications**

#### *6.1.1 Peritoneal entry*

Accidental peritoneal entry during full-thickness TEM excision was in the past considered a serious complication requiring an aggressive management by conversion to standard laparotomy anterior resection (LAR) and fecal diversion [18, 42, 43]. More recently, larger transanal minimally invasive resection series showed a rate of peritoneal entry ranging from 0 to 32% [44, 45]. Proposed risk factors for accidental peritoneal opening include full-thickness TEM excision of lesions located in the upper rectum and in the anterior and lateral rectal wall [46–48]. These papers also demonstrated that for a surgeon with appropriate skills in transanal surgery, peritoneal entry during TEM can be safely closed transanally with direct defect sutures without the need for abdominal exploration [45, 46] and was not followed by increased postoperative morbidity [45, 48, 49]. As previously demonstrated in large TEM series, [47, 48], the occurrence of peritoneal entry was not associated with increased risks of infectious or other postoperative complications, or longer hospital stay. Several series have also demonstrated that peritoneal entry during TEM resection of rectal cancer was not associated with worse oncologic outcomes [48, 49]. Peritoneal entry during TAMIS has not been as frequently reported as during TEM procedures. In a TAMIS systematic review of 390 patients published in 2014, only four cases of inadvertent peritoneal opening have been documented during dissection of low rectal lesions, and only one required laparoscopic assistance for closure of the defect [50]. TAMIS experience for resection of upper rectal lesion is still limited in

### *Local Excision for the Management of Early Rectal Cancer DOI: http://dx.doi.org/10.5772/intechopen.105573*

the literature, and among recent TAMIS series, the rate of peritoneal entry ranged from 0 to 10% [51–53]. However, a total of seven cases of peritoneal entry during TAMIS for upper rectal tumors have been described, six of which required conversion to laparoscopy or laparotomy. A recently published systematic review of 12 series of TEM procedures, including 4395 patients report that the rate of perforation into the peritoneal cavity was 5.1%, and conversion to an abdominal approach was required in 0.8% of cases [54]. Risk factor analysis identified anterior [46, 47] and upper rectal [45] tumor locations as significant risk factors for peritoneal entry. Also female sex during excision of anteriorly located lesions has been advocated as a risk factor due to the lower reflection of the anterior peritoneum in the female pelvis. Some authors state that in experienced hands, the majority of peritoneal defects could be closed transanally with significant decrease in conversion rate [49]. It is important to note that the definition used for peritoneal entry across different series is really heterogeneous, including: "major leakage of CO2 into the abdominal cavity resulted in significant technical difficulties" [55], "visible entrance into the peritoneal cavity" [46], "direct visualization of the defect during surgery" [45], while many studies do not explicitly state how they defined peritoneal entry [47, 48].

Transanal endoscopic direct closure of peritoneal defects appears to be feasible in more than 90% of cases, but it requires a significantly longer operating time (207.5 vs. 131.5 min) [55] from the increased technical complexity due to the loss of pneumorectum, producing a limited endoluminal vision and a troublesome reach of the peritoneal defect by the surgical instruments [49]. Authors experienced in both TEM and TAMIS transanal tumor excision have also suggested to shift to the TEM platform in case of peritoneal entry during TAMIS dissection, particularly for anterior and upper rectal lesions, to better manage the transanal peritoneal suture. This is due to the advantage offered by the rigid and longer rectoscope that is included in the TEM platform, which maintains the rectal wall stented allowing to suture the defect without the need for conversion [55]. In conclusion, peritoneal entry during local excision of a rectal tumor is a recognized intraoperative complication that can be adequately managed by endoluminal direct closure of the defect, not affecting the short- and long-term oncological results. However, extensive surgeon experience in transanal minimally invasive resection is required, together with the ability to use different transanal platforms. In the decision-making process for patient selection, the risk factors for peritoneal entry should be evaluated, considering the upper and anterior location of the lesion as an increased risk factor for this complication.
