Risk factors for leak, complications and mortality after ileocolic anastomosis: comparison of two anastomotic techniques

Introduction There are no definitive data concerning the ideal configuration of ileocolic anastomosis. Aim of this study was to identify perioperative risk factors for anastomotic leak and for 60-day morbidity and mortality after ileocolic anastomoses(stapled vs handsewn).

This is a STROBE-compliant study. Demographic and surgical data were gathered from patients with an ileocolic anastomosis performed between November 2010 and September 2016 at a tertiary hospital. Anastomoses were performed using standardised techniques. Independent risk factors for anastomotic leak, complications and mortality were assessed.

We included 477 patients: 53.7% of the anastomoses were hand sewn and 46.3% stapled. Laterolateral anastomosis was the most common configuration (93.3%). Anastomotic leak was diagnosed in 8.8% of patients and 36 were classified as major anastomotic leak (7.5%). In the multivariate analysis, male sex (P = 0.014, odds ratio, OR, 2.9), arterial hypertension (P = 0.048, OR 2.29) and perioperative transfusions (P < 0.001, OR 2.4 per litre) were independent risk factors for major anastomotic leak. The overall 60-day complication rate was 27.3%. Male sex (31.3% vs female 22.3%, P = 0.02, OR 1.7), diabetes (P = 0.03 OR 2.0), smoking habit (P = 0.04, OR 1.8) and perioperative transfusions (P < 0.001, OR 3.3 per litre) were independent risk factors for postoperative morbidity. The 60-day-mortality rate was 3.1% and no significant risk factors were identified.

Anastomotic leak after ileocolic anastomosis is a relevant problem. Male sex, arterial hypertension and perioperative transfusions were associated with major anastomotic leak. Conversion to open surgery was more frequently associated with perioperative death.

Ileocolic anastomosis, Anastomotic leak, Risk factors, Handsewn, Stapled

Morbidity associated with anastomoses is a determining factor for patient outcome after colorectal surgery. Since the introduction of the stapling devices in colorectal surgery, anastomosis configuration and method have been matter of discussion. Anastomotic leak involves many factors related to the patient, the underlying disease, the hospital setting and surgeon expertise.1–3 Among them, anastomotic configuration and technique represent two important, modifiable factors. Despite the significant technical advancements, the choice of the technique (handsewn vs stapled) of ileocolic anastomosis does not currently follow universally agreed criteria; rather, it is left to the preference of the surgeon. According to the most recent meta-analysis on the topic,4 including seven studies with 1125 patients, a lower anastomotic leak rate was detected with stapled sutures compared with handsewn (2.5 vs 6%; odds ratio, OR, 0.48; range 0.24–0.95). However, more recent multicentric cohort studies showed a lower leak rate with handsewn anastomoses.3,5,6 Besides anastomotic leak, other factor may be responsible for morbidity after ileocolic resection or right colectomy. The main aim of this study was to identify preoperative and intraoperative risk factors for anastomotic leak after ileocolic anastomosis, according to different anastomotic techniques. Secondary aims included the assessment of factors associated with overall morbidity and mortality.

This is a retrospective, observational study including a consecutive series of patients in whom an ileocolic anastomosis was performed as part of elective or emergency (within 24 hours of hospital admission) colorectal procedure. Patients admitted at a tertiary hospital between November 2010 and September 2016 were included in a prospective database. In case of incomplete or discordant data, an evaluation of the clinical history was performed retrospectively. The study was approved by the ethical committee for clinical research of the hospital. The following variables were analysed as possible risk factors for anastomotic leak: demographic data (age, sex), comorbidities (American Society of Anaesthesiologists, ASA, score, oral anticoagulants, smoking habit, high blood pressure and diabetes), preoperative nutritional status (serum total protein), surgical details (emergency vs elective, type of surgeon, surgical approach, perioperative transfusions) and characteristic of the disease (cancer vs. benign, localisation, anastomotic technique and configuration, extended resection). Anastomotic leak, complications and mortality were evaluated 60 days after surgery, using the Dindo–Clavien classification.7 Pathological details were evaluated (TNM system). All patients received intravenous antibiotic prophylaxis perioperatively following the policy at our centre (piperacillin/tazobactam 4/0.5 g) and elective patients were preoperative prepared only with a soft clear liquid regimen at home. Handsewn anastomosis was performed in a side-to-side interrupted and continuous double-layer suture of Vicryl®. Stapled anastomosis was performed side-to-side with a linear stapler and an additional firing to resect the specimen and close the defect. Occasionally, an end-to-side with a circular stapler (end-to-end anastomosis, EEA) was performed: the EEA anvil was placed into the end of small bowel and the EEA stapler passed through a colotomy and coupled to the spike to the EEA anvil; a linear stapler was used to close the colon defect. Data on complications and mortality were recorded. The expertise of the operating surgeon (colorectal vs general surgeon) was included in the analysis. Anastomotic leak was defined according to the 1991 UK Surgical Infection Study Group,8 meaning ‘a leak of luminal contents from a surgical join between two hollow viscera’ diagnosed (1) radiologically, by a radiographic enema with hydrosoluble contrast or by computed tomography (CT) with presence of intra- abdominal collection adjacent to the anastomoses; (2) clinically, with evidence of extravasation of bowel content or gas through a wound or drain; (3) by endoscopy; or (4) intraoperatively. In the present study, perianastomotic abscesses were also considered anastomotic leak and the radiological examination was performed in case of clinical or analytical suspicion of anastomotic leak. The anastomotic leak was defined as ‘major’ when classified as Dindo–Clavien III–V. The study adheres to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines for observational studies.9 Statistical analysis Continuous variables are reported as median and interquartile ranges (25th to 75th percentile), whereas categorical variables are reported as total number and percentage. Differences in length of hospital stay between groups were assessed with the Kruskal–Wallis test. A univariate analysis was performed to evaluate the association between the study variables (major anastomotic leak, complications and mortality) and the different independent variables. Continuous and categorical variables were analysed with Mann–Whitney U test and chi square tests, respectively. Independent variables associated with the outcome variables with P-value less than 0.1 were included into a logistic regression model to determine the independent risk factors. A P-value less than 0.05 was considered statistically significant (two-tailed test). The Statistical Package for Social Sciences version 22.0.0 was used.

A total of 508 consecutive patients received an ileocolic anastomosis in the study period; 31 of them were excluded from the analysis, because they also received other anastomoses (Fig 1). Data on 477 patients were included and analysed: 262 (54.9%) men and 215 (45.1%) women, with a median age of 67 years (range 53–77 years). Most were ASA II (58.1%) and III (29, 6%); 340 patients underwent surgery for cancer (71.3%), 93 for IBD (19.5%) and 44 (9.2%) for different conditions (9 ileostomy reconstruction, 8 obstruction, 7 ischemia, 7 appendicitis, 5 perforations, 2 diverticulitis, 2 post-radiotherapy enteritis, 2 endometriosis, 1 digestive haemorrhage and 1 volvulus). Eighty three percent of the procedures were elective. Laparoscopy was used for 31.9% of the patients, with a conversion rate of 4.2%. There was a very similar distribution in technique of construction of the anastomosis (53.7% handsewn vs 46.3% stapled). Side-to-side (93.3%) was the most frequent configuration. A diverting stoma at the time of ileocolic anastomosis was performed in five patients (1%). Demographic, preoperative, intraoperative, and pathological data are detailed in Table 1. Table 1. | Variable | Patientsa | | | (n) | (%) | | | Age, years (range) | 67 (53–77) | | | Sex: | || | Male | 262 | 54.9 | | Female | 215 | 45.1 | | ASA score: | || | I–II | 323 | 67.7 | | III–IV | 154 | 32.3 | | Anticoagulants: | || | No | 434 | 91 | | Yes | 43 | 9 | | Active smoker: | || | No | 398 | 83.4 | | Yes | 79 | 16.6 | | Arterial hypertension: | || | No | 262 | 54.9 | | Yes | 215 | 45.1 | | Diabetes: | || | No | 383 | 80.2 | | Yes | 94 | 19.8 | | Serum total protein (g/dl) | 7 | 6–7 | | Serum haemoglobin (g/dl) | 12 | 11–14 | | Baseline disease: | || | Cancer | 340 | 71.3 | | Inflammatory bowel disease | 93 | 19.5 | | Other | 44 | 9.2 | | Disease location: | || | Appendix | 10 | 2.1 | | Ileocecal | 99 | 20.8 | | Cecum | 112 | 23.5 | | Ascending colon | 133 | 27.9 | | Hepatic flexure | 45 | 9.4 | | Transverse colon | 31 | 6.5 | | Other | 47 | 9.8 | | Surgeon expertise: | || | Colorectal | 396 | 83 | | Non-colorectal | 81 | 17 | | Type of surgery: | || | Elective | 396 | 83 | | Urgent | 81 | 17 | | Surgical approach: | || | Open | 305 | 63.9 | | Laparoscopy | 152 | 31.9 | | Laparoscopy converted | 20 | 4.2 | | Anastomosis technique: | || | Handsewn | 256 | 53.7 | | Stapled | 221 | 46.3 | | Anastomosis configuration: | || | Side-to-side | 445 | 93.3 | | Side-to-end | 2 | 0.4 | | End-to-side | 29 | 6.1 | | End-to-end | 1 | 0.2 | | Perioperative transfusion: | || | No | 386 | 80.9 | | Yes | 91 | 19.1 | | Protective stoma: | || | No | 472 | 99 | | Yes | 5 | 1 | | TNM stage: | || | 0 | 198 | 41.6 | | I | 55 | 11.6 | | II | 109 | 22.8 | | III | 73 | 15.3 | | IV | 42 | 8.7 | | Extended resection: | || | No | 444 | 93.1 | | Yes | 33 | 6.9 | ASA, American Society of Anaesthesiologists; IBD, inflammatory bowel disease. a Results are n (%) or median (25th to 75th percentiles). The 60-day morbidity rate was 27.3%. The most frequent complications were surgical site infections (11.7%), followed by anastomosis-related complications (11.3%). Thirty-eight patients required surgical reintervention (8%). Anastomotic leak was diagnosed in 42 patients (8.8%); 36 (7.5%) of them were classified as major anastomotic leak. In eight patients (22.2%) anastomotic leak was managed with radiological drainage, whereas the remainder 30 were reoperated (77.8%). A terminal ileostomy was performed in 12 patients. Thirty-eight percent of the anastomotic leaks were diagnosed after hospital discharge and required readmission. Sub-analyses were performed according to the expertise of surgeons and indications to surgery. Open surgery was more frequently adopted by non-colorectal surgeons (91.4% vs 54.3%, P < 0.001) but no differences were found in anastomotic leak (P = 0.607). In patients with inflammatory bowel disease, 18 were already being treated with steroids (19.4 %), which was not associated with risk of anastomotic leak (P = 0.484). The mortality rate after 60 days was 3.1% (one-third due to anastomotic leak and two-thirds due to complications unrelated to the anastomosis). In patients with anastomotic leak, the mortality rate increased significantly (13.9% in patients with anastomotic leak vs 2.3% in patients without, P < 0.0001). The median postoperative length of stay was seven days (range 6–10 days). Length of stay was seven days (range 6–9 days) in uncomplicated patients compared with 9 days (range 8–13 days) in patients with other than anastomotic leak postoperative complication and 21 days (range 9–33.5 days) in patients with anastomotic leak (P < 0.0001). The variables associated with major anastomotic leak in the univariate analysis are shown in Table 2. In the multivariate analysis, the following variables were independent risk factors for major anastomotic leak: male sex (OR 2.92, P = 0.014), high blood pressure (OR 2.29, P = 0.048) and perioperative transfusions (OR 2.4 per litre, P < 0.001) (Table 2). A trend towards higher anastomotic leak rate was observed after stapled compared with handsewn anastomosis (10% vs 5.5%, P = 0.07). Table 2. | Variables | Major anastomotic leak | P-value | Odds ratio (multivariate analysis) | 95 % CI | || | Yes (n = 36; 7.5%) | No (n = 441; 92.5%) | (univariate) | (multivariate) | ||| | Perioperative transfusion (litres) | 0.45 (0–0.92) | 0 (0–0) | < 0.001 | < 0.001 | 2.4 (per l) | 1.5–3.8 | | Arterial hypertension: | 0.007 | 0.048 | |||| | No | 12 (4.6) | 250 (95.4) | 1 | – | || | Yes | 24 (11.2) | 191 (88.8) | 2.29 | 1.009–5.2 | || | Sex: | 0.012 | 0.014 | |||| | Female | 9 (4.2) | 206 (95.8) | 1 | – | || | Male | 27 (10.3) | 235 (89.7) | 2.92 | 1.24–6.86 | || | Anastomosis technique: | 0.06 | 0.07 | |||| | Handsewn | 14 (5.5) | 242 (94.5) | 1 | – | || | Stapled | 22 (10) | 199 (90) | 2.0 | 0.95–4.2 | || | Baseline disease: | 0.004 | 0.08 | |||| | Cancer | 26 (7.6) | 314 (92.4) | 1 | – | || | Inflammatory bowel disease | 2 (2.2) | 91 (97.8) | 0.5 | 0.09–2.3 | || | Other | 8 (18.2) | 36 (81.8) | 2.6 | 0.98–6.8 | || | Serum total protein (g/dl) | 7 (6–7) | 7 (6–7) | 0.10 | 0.14 | 0.7 (per g/dl) | 0.4–1.1 | | Surgical approach: | |||||| | Laparoscopic | 8 (5.3) | 144 (94.7) | 0.06 | 0.25 | 1 | – | | Open | 24 (7.9) | 281 (92.1) | 1.4 | 0.6–3.6 | || | Laparoscopic converted | 4 (20) | 16 (80) | 3.34 | 0.8–13.9 | 95% CI, 95% confidence intervals for multivariate analysis.

are n (%) or median (25th -75th percentiles) Risk factors associated with 60-day postoperative morbidity are summarised in Table 3. The following variables were risk factors for postoperative morbidity in the multivariate analysis: sex (male 31.3% vs female 22.3%, OR 1.7, P = 0.02), smoking habit (OR 1.8, P = 0.04), diabetes (OR 2.0, P = 0.02) and perioperative transfusions (OR 3.3 per litre, P < 0.001). No independent risk factors for mortality were identified at multivariate analysis (Table 4). Table 3. | Variables | Complicationsa | P-value | Odds ratio (multivariate analysis) | 95 % CI | || | Yes (n = 130; 27.2%) | No (n = 347; 72.8%) | (univariate) | (multivariate) | ||| | Perioperative transfusion (litres) | 0 (0–0) | 0 (0–0) | < 0.001 | < 0.001 | 3.3 (per l) | 2.1–5.3 | | Sex: | 0.02 | 0.02 | |||| | Female | 48 (22.3) | 270 (70.5) | 1 | – | || | Male | 82 (31.3) | 77 (81.9) | 1.7 | 1.08–2.7 | || | Diabetes: | 0.02 | 0.03 | |||| | Yes | 113 (29.5) | 270 (70.5) | 1 | – | || | No | 17 (18.1) | 77 (81.9) | 2.0 | 1.08–3.7 | || | Current smoker: | 0.009 | 0.04 | |||| | Yes | 99 (24.9) | 299 (75.1) | 1 | – | || | No | 31 (39.2) | 48 (60.8) | 1.8 | 1.04–3.2 | || | Surgeon expertise: | 7 (6–7) | 7 (6–7) | 0.003 | 0.07 | 0.4–1.1 | | | Colorectal | 97 (24.5) | 299 (75.5) | 1 | ||| | Non-colorectal | 33 (40.7) | 48 (59.3) | 0.8 | 0.4–1.5 | || | Baseline disease: | 0.044 | 0.3 | |||| | Cancer | 88 (25.9) | 252 (74.1) | 1 | – | || | Inflammatory bowel disease | 23 (24.7) | 70 (75.3) | 0.8 | 0.4–1.5 | || | Other | 19 (43.2) | 25 (56.8) | 1.6 | 0.7–3.3 | || | Surgical approach: | |||||| | Laparoscopic | 34 (22.4) | 118 (77.6) | 0.028 | 0.3 | 1 | – | | Open | 86 (28.2) | 219 (71.8) | 1.1 | 0.7–1.9 | || | Laparoscopic converted | 10 (50) | 10 (50) | 2.4 | 0.8–6.6 | 95% confidence intervals for multivariable analysis. a Results are n (%) or median (25th to 75th percentiles). Table 4. | Variables | Deatha | P-value | Odds ratio (multivariate analysis) | 95 % CI | || | Yes (n = 15; 3.1%) | No (n = 462; 96.9%) | (univariate) | (multivariate) | ||| | Age (years) | 80 (70–83) | 67 (52–77) | < 0.001 | < 0.001 | 3.3 (per l) | 2.1–5.3 | | Surgical approach: | |||||| | Laparoscopic | 1 (0.7) | 151 (99.3) | |||| | Open | 12 (3.9) | 293 (96.1) | |||| | Laparoscopic converted | 2 (10) | 18 (90) | |||| | Arterial hypertension: | 0.02 | 0.02 | |||| | No | 3 (1.1) | 259 (98.9) | 1 | – | || | Yes | 12 (5.6) | 203 (94.4) | 1.7 | 1.08–2.7 | || | Perioperative transfusion | 0 (0–0.9) | 0 (0–0) | 0.03 | 0.2 | 1.5 | 0.7–3 | | Baseline disease: | 0.017 | 0.2 | |||| | Cancer | 11 (3.2) | 329 (96.8) | 1 | – | || | Inflammatory bowel disease | 0 | 93 (100) | 0.7 | 0.5–1.2 | || | Other | 4 (9.1) | 40 (90.9) | 3.7 | 0.8–13.3 | || | Serum haemoglobin (g/dl) | 11 (9–13) | 12 (11–14) | 0.045 | 0.3 | 0.8 | 0.6–1.2 | | Surgeon expertise: | 0.016 | 0.4 | |||| | Colorectal | 9 (2.3) | 387 (97.7) | 1 | – | || | Non-colorectal | 6 (7.4) | 75 (92.6) | 1.7 | 0.5–5.4 | || | ASA score: | 0.002 | 0.5 | |||| | I–II | 4 (1.5) | 319 (98.5) | 1 | – | || | III–IV | 11 (7.2) | 143 (92.8) | 1.6 | 0.4–5.8 | ASA, American Society of Anaesthesiologists; 95% CI, 95% confidence intervals for multivariable analysis. a Results are n (%) or median (25th to 75th percentiles).

The present study showed an anastomotic leak rate for ileocolic anastomoses of 8.8%, at the upper limit of the range described in the literature.3–6,10–16 Of note, we classified CT-detected intra-abdominal abscesses as anastomotic leak. Furthermore, our 60-day follow-up was longer than that used in the majority of the other studies, therefore including all late anastomotic leaks occurring after hospital discharge. Recent large studies carried out in Spain and Europe with a similar anastomotic leak definition and follow-up, found anastomotic leak rate similar to the present study.5,17 Major anastomotic leak rate in our series was 7.5%, similar to other national prospective series,3,18,19 and a higher anastomotic leak rate after non-cancer/inflammatory bowel disease indications for surgery (18%) was found, which undoubtedly affects the results. This leak rate is likely to be more realistic than that obtained from analysis of national registries, in which patients are inserted on a voluntary basis, probably resulting in anastomotic leak rate being underestimated. Our series confirmed the importance of patient preoperative status as a risk factor for complications after colorectal surgery. It also showed that high blood pressure is a risk factor for anastomotic leak and postoperative mortality, confirming the results suggested by others.20,21 Ischaemia of anastomotic tissues is advocated as a cause of anastomotic leak, but the fact that, during anaesthesia, blood pressure tends to decrease resulting in episodes of intraoperative hypotension and microvascular ischemia is often underestimated. Hypertensive patients are prone to experience intraoperative haemodynamic instability, which can affect postoperative outcomes, such as increasing anastomotic leak,22 poor graft function after transplantation and postoperative mortality.23 Hence, this study suggested a role for prehabilitation in patients with high blood pressure in the perioperative phase of colorectal surgery,24 and warranted the need to investigate further the potential effects of inotropes/vasopressors. Regulating their use during surgery might be useful to optimise blood flow and pressures, as well as splanchnic vasoconstriction, tissue hypoxia and any possible risk factor for anastomotic leak. The importance of patient optimisation in the present series is suggested by the low anastomotic leak rate in patients with inflammatory bowel disease. We would suggest that most underwent elective surgery by surgeons with expertise in colorectal surgery, given that fewer than 20% of them were receiving steroids at the time of surgery. In this study, anastomotic technique was not significantly associated with anastomotic leak at multivariate analysis (P = 0.07). However, we observed a trend towards a higher rate of anastomotic leak after stapled anastomosis (OR 2.0, 95% confidence interval 0.95–4.2). These results are in contrast with a Cochrane meta-analysis,4 in which stapled ileocolic anastomosis was associated with a lower anastomotic leak rate compared with handsewn anastomosis. In the meta-analysis,4 anastomotic leak rate was 1.0% (3/300) after stapled anastomosis and 4.2% (22/525) after handsewn anastomosis. However, the studies included in this meta-analysis were not methodologically homogeneous and most of them included small samples of patients.11–16 In agreement with our findings, recently published multicentric, prospective, observational studies showed a decrease of anastomotic leak rate with handsewn anastomoses,3,5,6,10 highlighting the necessity for a well-designed and conducted randomised study to determine which is the best technique for ileocolic anastomoses. This study also confirmed the need of restricting or preventing perioperative transfusions, since they are associated with increased risk of anastomotic leak, morbidity and mortality. Blood transfusions cause immunosuppression and they can increase the risk of infectious complications and anastomotic leak after colorectal resections,25–27 even if no definitive agreement exists.27 Although the pattern has not been fully clarified yet, some evidence suggests that transfusions affect the cellular immune response, the activity of natural killer cells and antigens of macrophages presentation, decreasing the T-helper-suppressor ratio, which plays an important role in the immune system and the wound healing process.27,28 Mortality rate in the present analysis was 3.1%, similar to that described in previous studies on the topic, ranging from 0% to 6.1%.3–6,10–16 Given the low number of death events, no risk factors for postoperative mortality could be identified, although national series have suggested some.29,30 Laparoscopy was associated with lower morbidity and mortality. The rate of laparoscopic approach was low (36.1%, with a conversion rate of 11.72%), but not dissimilar to that reported in other European series.3,5,6 These results are similar to those found in other studies, and conversion to open surgery could cause higher complication/mortality rates and longer length of stay compared with laparoscopy.3,31 Furthermore, in the present study, an important difference in the rate of complications between colorectal and general surgeons was found (24.5% vs 40.7%, P = 0.07, OR 1.7). Previous studies suggested the importance of surgeon specialisation as a risk factor for anastomotic leak.1,2 However, it should be considered that most non-colorectal surgeons were operating on in emergency settings out of hours, and they were less commonly preforming the more straightforward, elective operations. This factor might also explain their higher overall complication rate. To our knowledge, this study represents the largest standardised, single-centre series of ileocolic anastomoses published so far. Even if limited by the retrospective fashion and by the fact itself of having being performed in a single centre, the study has strengths. Procedures were standardised and performed in a referral hospital with a dedicated colorectal unit, with homogeneous techniques for handsewn and stapled anastomoses and a close follow-up of patients, therefore offering a real-life picture of the outcome of ileocolic anastomoses. Reporting bias due to deliberate omission of data uploading is a limitation affecting most of the prospective registries and audits on the topic.5 We included all consecutive patients with ileocolic anastomosis, who fulfilled the inclusion criteria, thereby removing the bias. In addition, risk factors for complications and mortality were evaluated and confounding factors were removed by means of multivariable regression analysis.

Anastomotic leak after ileocolic anastomosis still represents a significant clinical issue, even at tertiary, high-volume centres with a homogeneous anastomosis technique. Multicentric, adequately powered, correctly designed and conducted, randomised studies are desirable, in order to determine the best technique to perform an ileocolic anastomosis. Several perioperative factors – either modifiable (e.g. arterial hypertension and perioperative transfusions) or not modifiable (e.g. male sex) – can independently increase the risk of major anastomotic leak. Analyses and studies aimed at establishing the ideal conformation of ileocolic anastomoses need to take into account all factors which can contribute to the success or failure of each given technique.

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