This study protocol was reviewed and approved by the Institutional Review Board of Helsinki University Hospital (No. HUS/115/2020) and this study adhered to the Declaration of Helsinki and the International Conference on the Harmonization of Good Clinical Practice. Finnish law allows for the use of medical records in medical research without necessitating the patient’s consent. The requirement for informed consent was waived in accordance with national guidelines by the Institutional Review Board of Helsinki University Hospital because of the retrospective nature of the study.

A single-center, retrospective study was carried out including all consecutive patients undergoing elective laparoscopic right hemicolectomy or extended right colectomy for malignant or benign neoplastic disease between January 2017 and December 2019. The exclusion criteria were emergency surgery, open surgery, active Crohn disease, and age under 18 years. A total of 499 patients were included. Of these, all patients with >80% ERAS adherence (n = 271) were included in further analysis. Results of patients with <80% ERAS adherence are shown as a comparison.

All the patients were treated according to our ERAS program optimized for elective colonic surgery. Our ERAS program was developed based on the ERAS Society guidelines for elective colorectal surgery [6].

Preoperatively, all elective patients meet a multidisciplinary team of a surgeon, a colorectal nurse, and an anesthesiologist in a predefined order. Detailed information on the planned surgical procedure is given. One month’s abstinence from alcohol and smoking is recommended. The nurse supervises the peroral intake on the day of surgery: clear fluids are allowed up to 2 hours, and solids up to 6 hours before the induction of anesthesia [7]. A preoperative carbohydrate drink is advised to be taken 2 hours prior to hospital arrival [89]. Medication is optimized (most importantly, peroral anticoagulants are paused and replaced) and prophylaxis against thrombosis is planned [89]. Compression stockings are measured to fit well. All instructions are given in both verbal and written forms.

A standardized anesthesia protocol is followed. Premedication is given only as an exception. Standard antimicrobial and postoperative nausea and vomiting (PONV) prophylaxes are administered [1011]. Cefuroxime prophylaxis is repeated if surgery is prolonged (>3 hours) and in case of extensive (>500 mL) bleeding [12]. The patient is kept normothermic and fluid balance is monitored with a restricted goal [1314]. Purely ropivacaine-based transversus abdominis plane (TAP) block, or rarely thoracic epidural analgesia (TEA), is preferably applied preoperatively or at the beginning of surgery for perioperative analgesia [15]. Paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs) (when no contraindications) are routinely used postoperatively. In the recovery room, patients are encouraged to drink 100–200 mL of fluids and are mobilized to sitting or standing. The time in the recovery room is kept reasonably short so the patient may benefit sooner from the better facilities for mobilization in the ward.

In the ward, oral fluids and supplements are given from the day of surgery [16]. Solid food is offered from the postoperative day (POD) 1 onwards [17]. Total fluid intake is kept at 20–30 mL/kg per day and intravenous (IV) administration is used if needed. Low molecular weight heparin is administered. With multimodal pain management, opioid use is kept low. Early mobilization is encouraged with the aim of spending a minimum of 6 hours out of bed from POD 1, with a physiotherapist being consulted when needed [18]. Urinary and epidural catheters are removed on POD 1 and 2, respectively [19].

The criteria for safe discharge are adequately controlled pain (oral analgesics), independent mobilization, normal diet (soup/solid), passage of air/stool and urine, and normothermia.

A standard laparoscopic procedure for right hemicolectomy or extended right colectomy was performed. Patients with malignant diagnoses were treated according to oncological principles. In the group of patients undergoing handsewn extracorporeal anastomosis (ECA), the resected bowel was extracted through a 5–7 cm incision in the upper right quadrant (or upper left in case of extended right colectomy). A plastic wound protector (Alexis, Applied Medical) was used. The anastomosis was performed end-to-end with 4-0 absorbable monofilament continuous suturing. In the stapled ECA group, the bowel was similarly extracted, and the anastomosis was performed with a GIA linear stapler (Medtronic), preferably side-to-side in an isoperistaltic fashion. The enterocolotomy was closed with 4-0 or 3-0 polydioxanone. For the patients undergoing intracorporeal anastomosis (ICA), the anastomosis was performed side-to-side in an isoperistaltic fashion intracorporeally using The Signia stapling system by Medtronic. The enterocolotomy was closed with a 3-0 V-loc (Medtronic) continuous double-layer suturing technique. Afterward, the resected bowel was extracted from a mini-Pfannenstiel opening. The fascial level of the extraction wound was closed with 2-0 absorbable monofilament continuous suturing. As part of our normal ERAS protocol, all the patients received prophylactic antibiotics within 1 hour before the surgical incision. Considering the possible risk of perioperative contamination in performing ICA, the ICA group received 3 doses of antibiotics postoperatively (a combination of cefuroxime and metronidazole).

In this study, all the patients were operated on or assisted and supervised by 1 or 2 experienced colorectal surgeons. Residents under the supervision and assistance of an experienced consultant performed only 7.0% of all the operations (19 of 271), in all of which a handsewn ECA was performed.

The incidence and predictive factors for postoperative ileus were analyzed as the primary outcome. Postoperative ileus was defined as abdominal distention with PONV from POD 2, a clinical or radiological confirmation of ileus, and an inability to tolerate oral intake from POD 2. Most of the patients were treated with a nasogastric tube. Additionally, the time to the first bowel movement after surgery was recorded and reported.

Other short-term postoperative complications (including the rate of anastomotic leakages, reoperations, and postoperative infections) and the length of hospital stay were analyzed as secondary outcomes. All complications were recorded using the upgraded Clavien-Dindo classification for colorectal surgery [20]. The Comprehensive Complication Index within 30 days after surgery was calculated as the sum of all complications, weighted for severity. The postoperative care, observations, and patient discharge were conducted according to the department’s ERAS protocol. Over 80% ERAS adherence was demanded for the patient to be analyzed further. Postoperative pain was monitored using visual analog scale scores from 0 to 10 and the consumption of pain medication was recorded in the patient’s medical record.

Overall, data gathered from the electronic patient records included sex, age, diagnosis, body mass index (BMI), American Society of Anesthesiologist (ASA) classification, Chalson comorbidity index score (CCI-score), anticoagulant treatment, preoperative hemoglobin level, preoperative albumin level, IV iron infusions, preoperative bowel preparation, preoperative antibiotic administration, preoperative medication, type of anastomosis, conversion to open surgery, the operating staff, TEA, TAP block, PONV prophylaxis, drainage, nasogastric tube, normothermia, IV fluids on the day of surgery, urinary catheter (the length kept in place), antithrombosis, postoperative mobilization, postoperative po intake (fluids, solids), bowel function recovery (air, solid stool), C-reactive protein (CRP) level on POD 2 and 3, analgesic regimen (paracetamol, NSAIDs, oxycodone), complications, length of hospital stay, reoperations, readmissions, adjuvant therapy, 30-day mortality.

Statistical analyses were performed using IBM SPSS Statistics for Windows (ver. 29.0, IBM Corp.). Continuous variables with normal distribution (age, BMI, intraoperative bleeding, duration of operation) are expressed as means with standard deviation and were compared using the one-way analysis of variance. Continuous variables with non-normal distribution (ERAS adherence, amount of postoperative opioids, first bowel movement, length of hospital stay, and CCI-score) are expressed in medians with interquartile range and compared with nonparametric tests. Categorical variables (anastomotic dehiscence, ileus, reoperation, 30-day mortality, readmission) were analyzed by the Pearson chi-square test and Fisher exact test. Univariate and multivariate logistic regression analyses were performed to study the predicting factors for postoperative ileus. The enter method was used in the multivariate analysis. The statistical significance threshold was set at a 2-sided α of 0.05.

The data of 580 patients were collected in total. Patients with nonneoplastic diagnoses or patients who underwent procedures other than right hemicolectomy (ileocecal resection or caecum resection) were excluded. Of the remaining 499 patients, all of those with ≥80% ERAS adherence (n = 271) were included in further analysis. The median ERAS adherence among these 271 patients was 88.9% (interquartile range [IQR], 80%–90%; range, 80%–100%). The demographic characteristics are detailed in Table 1. Comparison is made to patients with under 80% ERAS adherence (n = 228).

The mean duration of operation was 175 minutes (range, 74–403 minutes) and the mean amount of intraoperative bleeding was 90 mL (range, 0–1,350 mL). The median need for postoperative opioids was 27 mg (IQR, 15–43 mg; range, 0–172 mg). The median first postoperative bowel movement was recorded at 2 days (IQR, 1–2 days; range, 0–4 days), and the median length of hospital stay was 4 days (IQR, 3–5 days; range, 2–28 days). These results are reported in detail in Table 2. The comparison was made to patients with under 80% ERAS adherence (n = 228). The difference was significant considering the need for postoperative opioids (P = 0.006) and the length of hospital stay (P = 0.007).

Of all the 271 patients with ≥80% ERAS adherence, 96 (35.4%) developed at least 1 complication. The CCI score was calculated for every patient. The median CCI score was 0 (IQR, 0–20.9; range, 0–47.7).

The rate of anastomotic dehiscence was 1.8%, and 2.2% of patients required reoperation. The 30-day readmission rate was 8.1% and 30-day mortality was 0%. These results are reported in detail in Table 3. The comparison was made to patients with under 80% ERAS adherence (n = 228). The difference was significant considering the rate of reoperations (P = 0.026).