Anastomotic leakage has always been a major clinical problem in rectal or anal anastomosis, however this complication after LAR still remains a challenging clinical problem that can lead to significant morbidity and mortality. The use of stapling devices, performing mid and low rectal cancer resections with TME that require radical dissection may lead to a higher rate of anastomotic leakage. The reported clinical leakage rate after anterior resection varies from 3 to 21% depending on the level of anastomosis, the method of reconstruction and surgical expertise. The post-operative mortality associated with anasto-motic complications ranges from 2 to 25%. On the other hand, the low local recurrence rate and improved survival after TME supports the necessity of the removal of the entire mesorectum. A low level of anastomosis is usually regarded as the significant risk factor increasing anastomotic leakage rate. As reported by Vignali et al. out of 1014 stapled rectal anastomoses, the leakage rates were 7.7 and 1% from anastomoses at a level below and above 7 cm from anal verge, respectively. In the report by Law et al., age, level of the tumour, level of the anastomosis, concomitant resection of the other organs, stage of disease and the technique of anastomosis were not significant factors. They found the gender of the patients and the presence of a stoma were the most important and independent risk factors for anastomotic leakage. The difference may be explained by the anatomical differences of the pelvis between males and females and might only become significant when the anastomosis is performed at a low level. Leakage rate in men was 13.4% while that in women was 5.2% (p=0.049). The presence of a stoma was associated with a lower leakage rate. In the group with proximal diversion, the leakage rate was 4.8% while that of the group without diversion was 16.1% (p=0.008). Moreover, in the male patients, the leakage rates in those with and without proximal diversion were 5 and 27% respectively (p=0.001) and in the female patients the presence of a stoma had no effect of the anastomotic leakage rate. Therefore Law et al. recommend routine creation of a stoma in male patients.
However, the relationship between a diversion stoma and anastomosic leakage is more controversial. Many studies did not find a lower leakage rate in patients with proximal diversion. In patients with anastomotic leakage, both conservative and surgical options (diversion stoma, Hartmann's procedure) may be considered. Conservative treatment for anas-tomotic leakage is usually possible in the presence of proximal diversion. Although the double stapling technique enables low rectal anastomoses, the transanal CAA still has its role. According to some surgeons, tumours at a level 2-3 cm from the dentate line were treated with transanal CA to preserve the anal sphincter. Enker et al. reported the low leakage rate in CAA after LAR in 1985. Law et al. did not find any statistical difference in leakage rate between double stapling and handsewn CAA. The low leakage rate of CAA may be due to the routine proximal diversion in the CAA. The anal canal may have a relatively better blood supply as compared with the ischaemic rectum stump after TME. The routine use of J-colon pouch may also be one of the reasons accounting for the low leakage rate. Hallbook et al. reported significantly lower leakage rates in colonic J-pouch anastomosis than straight anastomosis in a multicenter prospective randomised trial [91-93].
Stapled anastomosis besides its advantages is associated with the higher rate of anastomotic stenosis or stricture. The exact incidence of this complication is difficult to determine because the definition of stenosis is not well defined. Lett et al. and Fazio have defined a stricture as a narrowing that does not allow passage of a 15-mm sigmoidoscope. It is believed that, according to Kyzer and Gordon considered stenosis as any anastomosis that did not accept the 19-mm sigmoidoscope. The aetiology of anastomotic stenosis is not completely understood. When the colon is found to be ischaemic it may lead to further stricture above the anastomosis. It is proposed that stenosis may be caused by insufficient circulation in the marginal artery and this insufficiency may be aggravated also by irradiation. Experimental studies indicate that stapled anastomoses heal by second intention because the mucosa of the bowel segments is not in apposition but is separated by the muscular and serosal layers. Therefore, the precise stapled anastomosis predictably forms a perfect circular scar, which results in a narrowing of intestinal lumen. The stenosis is almost always subclinical and faecal dilatation ultimately provides for wide patient anastomosis [91, 94, 95]. Benign strictures arise in 5.8-20% of colorectal anastomoses. For such strictures, endoscopic dilation has proven to be a useful and safe treatment. Both through-the-scope balloon and over-the-wire pneumatic balloon dilation techniques are effective and safe for treatment of benign colorectal anastomotic strictures. Were et al. also reported good results after dilation of benign strictures following LAR using Savary-Gillard bougies [96, 97]. Yagyu et al.  found regular finger dilation of the anastomosis to be useful for preventing anastomotic stenosis after LAR. The role of temporary defunctioning stoma in patients undergoing LAR remains controversial. Grabham et al.  suggest that it should be performed in selective cases where there is a concern about the anastomosis due to difficult dissection, incomplete doughnuts and tension on anastomosis. Machado et al.  compared surgical outcome after LAR for rectal cancer with colonic J-pouch at two departments with a different policy regarding the use of a routine diverting stoma. A total of 161 patients with invasive rectal cancers were operated on between 1990 and 1997 with TME and a colonic J-pouch. Eighty patients were operated on in a surgical unit using routine defunctioning stomas (in 96%) whereas 81 were operated on in a department in which diversion was rarely used (5%). There was no difference between the two centres in post-operative mortality in connection with the primary resection and subsequent stoma reversal (3.7 vs. 3.8%). No significant difference could be found in the number of patients with pelvic sepsis (anastomotic leak: 9 vs. 12%). According to this study, the routine use of diverting stoma does not protect the patient from anastomotic complications or pelvic sepsis and requires a second admission for closure. Another interesting issue concerning LAR is small bowel obstruction as the impact of diversion ileostomy. Poon et al.  reviewed 214 patients who underwent LAR between 1993 and 1999 and were readmitted with the diagnosis of small bowel obstruction. Median follow-up was 39 months; 22 patients presented with 30 episodes of small bowel obstruction, and operations were necessary in nine patients (40.9%). Malignant obstruction occurred in two patients (10.3%). Obstruction within 6 weeks of surgery (including closure of stoma) occurred in 13 patients (6.1%). Early obstruction occurred at a higher incidence in those patients who had an ileostomy than in those who did not (9.1% vs. 2.9%, p=0.048). The Authors concluded that the presence of diversion ileostomy was associated with an increased incidence of early obstruction; therefore the use of loop ileostomy for proximal diversion should be further assessed.
The goals in the treatment of rectal cancer are cure, local control, and preservation of sphincter, sexual and bladder function. The complications and mortality rate in the setting of pre-operative chemoradiation have not been well defined. However, the results prompted the addition of adjuvant or neoadjuvant pelvic irradiation with or without chemotherapy to reduce local recurrence rates and improve survival rates. Pre-operative radiation therapy results in increased surgical complications and post-operative radiation therapy produces considerable short-term and long-term complications. Enker et al. assessed the pre-operative complications in association with pre-operative radiation. To determine the pre-operative morbidity rate associated with pre-operative radiation sequencing, patients receiving pre-operative chemoradiation were compared with those in the other groups (Pre-op RT «=150; No Pre-op RT «=531). All 681 patients underwent LAR for resection of primary rectal cancer. The type of surgical resection was distinguished between LAR (75%) and LAR with CAA (25%). One third of the patients undergoing CAA were stapled, two thirds underwent perianal sutured anastomoses. The leakage rate was significantly higher in patients undergoing LAR than those undergoing CAA. A temporary diverting ileostomy or colostomy was performed in 214 (31%) patients. Of the patients with a diverting stoma, 122 (57%) had a CAA. The leakage rate was no different among those with diversion or those without. In addition, a diverting stoma did not reduce the incidence of anastomotic leak among those undergoing LAR without CAA. The operative time, estimated blood loss and rate of pelvic abscess formation without associated leak were higher in the Pre-op RT group than the No Pre-op RT group. However, the overall complication rate and incidence of wound infection, anastomotic leaks and pelvic abscess formation not associated with a leak were compared between patients who did and did not receive pre-operative chemoradiation. The incidence of pelvic abscess formation was significantly higher in those who received pre-operative chemoradiation. Because LAR is a clean-contaminated procedure, localised sepsis in the contaminated radiated field is not surprising. It would be of interest to evaluate the potential efficacy of a more prolonged antibiotic course in patients receiving pre-operative radiation . Pucciarelli et al. reported that pre-operative combined RT and chemotherapy for rectal cancer did not affect early post-operative morbidity and mortality in LAR. They respectively compared 41 patients (Group A) with 30 patients (Group B) who in the same period underwent surgery without pre-operative adjuvant therapy. Minor post-operative complications that occurred in both groups (Group A - 51%, Group B - 62%) were anastomotic leak, middle and moderate anaemia, urinary tract infection, urinary retention, post-operative prolonged ileus, wound infection and bronchopneumonia. Major post-operative complications occurred in each group (p=NS). They were anastomotic leak, anasto-motic haemorrhage, descending colonic necrosis, rectovaginal fistula, haemoperitoneum and necrosis of gastric curvature, pelvic abscess and high output from ileostomy requiring readmission. Anastomotic leaks were treated conservatively with no further morbidity or reoperation. Of the two patients with rectovaginal fistulas, one underwent ileostomy and the other, who already had a diverting stoma, was given conservative treatment. One patient with an anastomotic haemorrhage was given endoscopically guided sclerosin injections. Three patients required reoperation for post-operative complications: one cirrhotic patient underwent reoperation for necrosis of anastomosed colon; the second patient required surgery for massive bleeding from the sacral veins; and the third one for ischaemic necrosis of the greater gastric curvature requiring emergency gastric resection. Conservative treatment was given for the remaining two major complications: a para-anasto-motic abscess and combined water and electrolyte deficit caused by the high output from the covering ileostomy. At multivariate analysis, ASA score 3, absence of diverting stoma, LAR with CAA, low pre-operative haemoglobin value and more intraoperative blood loss were found to be independent predictors of major complications. Whether pre-operative adjuvant therapy influences early post-operative mortality and morbidity is still controversial. Most of the studies report morbidity and mortality after preoperative adjuvant RT alone. Some Authors have found significant peri-operative mortality or morbidity rates or both, although others have not .
The advent of surgical stapling devices has resulted in a dramatic reduction in the number of abdominoperineal resections, however, transanal stapled anastomosis may be associated with continence disturbances and reduced post-operative anal sphincter function. Disorders of continence are present in up to 60% of all patients who undergo LAR for rectal cancer. It is likely that an anal stretch type of mechanism is responsible for internal sphincter injury that is seen on ultrasound .
Although anastomotic staplers are common in surgical practice and they allow more extended, lower resections of the colorectum, complications associated with stapler use have been reported. Anas-tomotic stricture and leakage is the most common. A unique complication following stapler use is colo-vaginal fistula during LAR. The management of a post-operative rectovaginal fistula after LAR for rectal cancer is difficult and requires reconstruction of the anastomotic site and fistula. One of the reconstructive operations is the technique using the posterior approach through the vaginal lumen for a high rectovaginal fistula repair. Wang et al. reported 140 patients who underwent LAR with a double-stapled anastomosis for rectal cancer. In 4 patients (2.9%) rectovaginal fistula (RVF) developed as a post-operative complication. The RVF developed gradually from 9 to 128 days after LAR. Authors performed modified transvaginal approach for RVF repair with a diverting colostomy. In all 4 patients, the RVFs were completely eradicated with re-establishment of intestinal continuity and did not recur during the mean follow-up period of 29.5 months . My preferred approach is laparotomy and excision of the anastomosis, and to perform a double-stapled anastomosis again.
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