Right-Sided Colon Surgery and Slower Bowel Recovery: What Patients Need to Know

Table of Contents

• Key Points
• Background: Why This Research Matters
• How the Study Was Conducted
• Key Findings: What the Researchers Discovered
• Understanding the Results: What the Authors Discuss
• Study Limitations: What This Research Couldn't Prove
• Recommendations for Patients
• Frequently Asked Questions
• Source Information

Key Points

• In a study of 384 colectomy patients, the first stool came later after right-sided than after left-sided surgery (median postoperative day 2 vs. day 1).
• Postoperative ileus occurred in 17% of right-sided and 14% of left-sided patients overall, a difference that was not statistically significant; among laparoscopic cases, rates were 15% vs. 7%, a statistically significant difference.
• Five factors were linked to higher odds of ileus: anastomotic leakage (the largest odds ratio, 58.22, with a wide confidence interval of 13.08–421.14), poor physical function (only 6 patients), conversion to open surgery, no oral bowel preparation, and open surgery.
• The study could not determine why bowel recovery is slower after right-sided colectomy; it was done at one hospital.

Background: Why This Research Matters

Over the past 20 years, elective colorectal surgery has experienced two major advancements: the introduction of laparoscopic (minimally invasive) surgery and the implementation of Enhanced Recovery After Surgery (ERAS) programs. ERAS consists of a set of evidence-based guidelines designed to minimize the body's stress response to surgery, reduce organ dysfunction, and promote rapid recovery. These programs have been shown to be safe, cost-effective, and associated with faster postoperative recovery, fewer complications, and shorter hospital stays.

Surgical removal of the colon (colectomy) can be performed on either the right side or the left side of the large intestine. Right-sided colectomy (removing the first portion of the colon, called the ascending colon) is often performed for cancers or growths (polyps) in that area. Left-sided colectomy (removing the descending colon or sigmoid colon) is frequently done for diverticular disease or cancers located on the left side.

It has long been believed by surgeons that recovery after right-sided colectomy is more challenging and prolonged compared to left-sided resection. This slower recovery is partly attributed to a higher incidence of postoperative ileus (POI) — a condition where the bowel temporarily stops functioning properly after surgery, causing nausea, vomiting, abdominal swelling, and the inability to pass gas or stool.

POI occurs in 10% to 17% of cases and is among the most common complications following abdominal surgery. Recent studies have identified right-sided colon resection as a risk factor for developing POI. However, the reasons behind slower functional recovery and higher POI rates in right-sided procedures remain poorly understood. This study was designed to compare bowel function recovery between right-sided and left-sided colectomies within a fully implemented ERAS program, and to identify risk factors for POI.

How the Study Was Conducted

This was a retrospective single-center study conducted at the General Surgery Department of the Martini General Hospital in Groningen, the Netherlands. The researchers used data from a prospective ERAS database, covering all patients who underwent elective (planned, non-emergency) colectomy between January 2017 and May 2020.

Patients were divided into two groups based on the type of surgery they received:

• Right-sided colectomy group: patients who underwent right hemicolectomy or ileocecal resection (removal of the end of the small intestine and beginning of the large intestine)
• Left-sided colectomy group: patients who underwent left hemicolectomy or sigmoid resection

Patients who had a transversectomy (removal of the middle portion of the colon) were categorized as right or left based on which flexure (the bend where the colon turns) the resection was closest to. All surgeries were performed or supervised by board-certified surgeons. The standard approach was laparoscopy, unless there were medical reasons against it. The anastomosis (reconnection of the bowel ends) was created using hand-sewing, stapling, or a combination of both.

The study measured several outcomes:

• ERAS protocol compliance — assessed as a yes/no answer for each of the 24 items in the protocol
• Functional recovery — time to first passage of gas (flatus), time to first bowel movement (stool), and ability to tolerate solid food, all measured in postoperative days (POD)
• Postoperative ileus — defined as the need for a nasogastric tube (a tube inserted through the nose into the stomach) due to persistent nausea, vomiting, and abdominal distension
• Clinical outcomes — complications, adverse events, and length of hospital stay. Complications were graded using the Clavien-Dindo classification system, a five-point severity scale

A post hoc analysis (an additional analysis performed after the main results were collected) was conducted including only patients who underwent elective laparoscopic surgeries, because open surgery is known to be associated with delayed functional recovery.

Statistical analysis was performed using RStudio version 1.2.5042. Continuous variables were expressed as median (interquartile range) or mean ± standard deviation, depending on their distribution. A p-value of less than 0.05 was considered statistically significant. A total of 48 patients were excluded from the risk factor analysis because they had incomplete data (a method called listwise deletion).

One important detail concerns oral bowel preparation. The ERAS protocol item is "no oral bowel preparation". Under the hospital's policy, patients undergoing right colectomy followed this item and had no bowel preparation, because of differences in intestinal content consistency. Patients undergoing left colectomy received oral bowel preparation, which is a deviation from the protocol. As we'll see, this affected the ERAS compliance numbers.

Key Findings: What the Researchers Discovered

Who Was in the Study?

A total of 384 patients were included in the analysis. Of these, 58% (223 patients) underwent right-sided colectomy, while 42% (161 patients) had left-sided resection.

Several differences existed between the two groups at the start of the study:

• Age: Right-sided patients were older — median 71 years (interquartile range 65–77) vs. 69 years (interquartile range 60–73) for left-sided patients (p < 0.001)
• Gender: 42% of right-sided patients were male vs. 58% of left-sided patients (p = 0.002)
• BMI: Left-sided patients had a significantly higher body mass index — 28 kg/m² vs. 26 kg/m² for right-sided patients (p = 0.001)
• Underlying disease: Right-sided patients more often had malignancy (cancer) — 85% vs. 75% — and more often had other benign conditions including polyps (10% vs. 3%). In contrast, diverticular disease was seen only in left-sided patients, representing 19% of surgical indications in that group (p < 0.001)

Other factors were similar between the groups, including smoking rates (14% in both), alcohol use, ASA scores (a measure of overall health before surgery), diabetes, heart disease, and lung disease. Only 2% of patients overall had a WHO performance score of 2 or higher (indicating limited physical activity), suggesting that most patients were in relatively good health before surgery.

Surgical Details: What Happened During the Operations

Several surgical characteristics were compared; only the differences in the length of surgery and in blood loss were statistically significant:

• Surgical approach: Laparoscopy was used more often for right-sided colectomies — 82% vs. 72% for left-sided procedures. Conversion to open surgery (switching from laparoscopy to a larger incision) occurred in 5% of right-sided vs. 9% of left-sided procedures. Open surgery (laparotomy) was performed in 13% of right-sided vs. 19% of left-sided cases (p = 0.07). Although this difference was not statistically significant, it trended toward more open/converted surgery in the left-sided group.
• Duration of surgery: Left-sided operations took significantly longer — median of 169 minutes (interquartile range 130–209) vs. 125 minutes (interquartile range 97–157) for right-sided operations (p < 0.001)
• Intraoperative blood loss: Left-sided surgeries caused more bleeding — median 0 ml in both groups, but with a wider interquartile range in the left-sided group (0–200 ml vs. 0–50 ml) (p < 0.001)
• New stoma: 1 of 223 patients in the right-sided group needed a new stoma vs. 4 of 161 patients (2%) in the left-sided group (p = 0.17)
• Opioid use: Similar in both groups — 77% of all patients received long-acting systemic opioids, 19% received short-acting opioids, and 4% received none

ERAS Compliance: Following the Recovery Protocol

Compliance with the ERAS protocol was significantly higher in patients undergoing right-sided colectomy: 70% vs. 66% for left-sided patients (p < 0.001). This difference was driven mainly by the preoperative phase, where the right-sided group achieved nearly 100% compliance compared to 84% in the left-sided group (p < 0.001). This was mainly due to the hospital's decision to give oral bowel preparation to left-sided colectomy patients, which is a deviation from the ERAS item "no oral bowel preparation".

Bowel Functional Recovery: The Core Finding

The study's central finding was that bowel function returned more slowly after right-sided colectomy:

• First passage of gas (flatus): Both groups passed gas at a median of 1 postoperative day, but the right-sided group had a wider interquartile range (1–2 days) compared to left-sided (1–1 day) (p < 0.001)
• First passage of stool: Right-sided patients had their first bowel movement at a median of 2 postoperative days (interquartile range 1–3), while left-sided patients had theirs at a median of 1 postoperative day (interquartile range 1–2) — a statistically significant difference (p < 0.001)
• Tolerance of solid food: Both groups tolerated solid food at a median of postoperative day 0 (interquartile range 0–1) (p = 0.48), meaning there was no significant difference in when patients tolerated solid food

Postoperative Ileus: A Key Complication

In the overall analysis:

• 37 patients (17%) who underwent right-sided colectomy developed POI
• 22 patients (14%) who underwent left-sided colectomy developed POI
• This difference was not statistically significant (p = 0.5)

However, when the researchers performed the post hoc analysis limited to laparoscopic surgeries only, the difference was statistically significant:

• 27 patients (15%) in the laparoscopic right-sided group developed POI
• 8 patients (7%) in the laparoscopic left-sided group developed POI
• This difference was statistically significant (p = 0.04)

In the laparoscopic subgroup, the time to first stool was also confirmed to be slower after right-sided surgery (median 2 days vs. 1 day, p < 0.001). The researchers believe that the higher rate of open and converted surgeries in the left-sided group contributed to a corresponding increase in the POI rate in that group, resulting in comparable POI rates between the two groups in the overall analysis. The post hoc analysis of laparoscopic procedures supported this assumption.

Complications and Hospital Stay

The groups did not differ significantly in the following outcomes:

• Complications during the primary (first) hospital stay: 98 right-sided patients (44%) vs. 59 left-sided patients (37%) experienced complications or adverse events (p = 0.18) — a difference that was not statistically significant
• Reoperations: among patients who had complications, 19 of 98 right-sided patients (19%) and 11 of 59 left-sided patients (19%) needed a reoperation (p > .999)
• Intensive care admissions: among patients who had complications, 10 of 98 right-sided patients (10%) and 4 of 59 left-sided patients (7%) were admitted to intensive care (p = 0.66)
• Anastomotic leakage (a leak where the bowel was reconnected) was the most common reason for reoperation: 8 of 19 reoperations (42%) in the right-sided group and 4 of 11 (36%) in the left-sided group, where mechanical bowel obstruction accounted for the same number
• Length of hospital stay: Median 4 days (interquartile range 2–6) for right-sided vs. 3 days (interquartile range 2–6) for left-sided patients (p = 0.5) — not statistically significant
• Readmissions: 7% for right-sided vs. 10% for left-sided patients (p = 0.44)

Risk Factors for Postoperative Ileus

The researchers identified six independent risk factors for developing POI using multivariate analysis (a statistical technique that accounts for multiple factors simultaneously):

1. Anastomotic leakage — the factor with the largest odds ratio (OR), 58.22 (95% confidence interval [CI] 13.08–421.14, p < 0.001). This means POI was much more likely in patients with a leak. The number 58 is an odds ratio, not a risk multiplier: it does not mean that POI was 58 times more likely. The estimate is also imprecise, as the wide confidence interval shows.
2. WHO performance score ≥ 2 — OR 16.33 (CI 1.61–168.91, p = 0.01). Patients with poorer physical function before surgery had higher odds of POI. Only 6 patients in the study had such a score.
3. Conversion to open surgery — OR 3.99 (CI 1.24–11.69, p = 0.02). Patients whose laparoscopic procedure was converted to open surgery had higher odds of POI.
4. Absence of oral bowel preparation — OR 3.93 (CI 1.73–10.01, p = 0.002). Not receiving oral bowel preparation was associated with higher odds of POI.
5. Laparotomy (planned open surgery) — OR 3.19 (CI 1.29–7.65, p = 0.01). Open surgery was associated with higher odds of POI than laparoscopy.
6. ASA score ≥ 3 — interestingly, this was associated with lower odds of POI (OR 0.27, CI 0.08–0.76, p = 0.02): after the other factors were taken into account, patients classified as higher surgical risk (ASA III–IV) had lower odds of POI in this study.

Other factors such as male gender, age over 70, BMI over 25, diabetes, heart disease, lung disease, presence of metastasis, preoperative malnutrition, new stoma, intraoperative blood loss over 500 ml, and surgery lasting more than 180 minutes did not reach statistical significance as independent risk factors. The side of surgery itself was also not a statistically significant risk factor for POI (in the univariate analysis, right-sided compared with left-sided: odds ratio 1.55, CI 0.85–2.92, p = 0.17).

Understanding the Results: What the Authors Discuss

This study confirms what many surgeons have long suspected: recovery of bowel function is delayed after right-sided colectomy compared to left-sided colectomy. The finding aligns with recent literature reports. The authors could not determine the cause of this difference. They discuss the following points.

First, the overall POI rate in this study was 15%. The authors write that this coincides with findings from other studies and a systematic review by Wolthuis et al., which reported POI prevalence in the general literature at closer to 10%. The authors note that the Wolthuis review had limitations, including the use of various definitions of ileus and reliance on low-quality data series.

Second, the two groups had different baseline characteristics. Right-sided patients were older and more often female, and had more cancer diagnoses. Left-sided patients had higher BMI, longer operations, more blood loss, and more open/converted surgeries. The authors point out that earlier studies have linked higher BMI, longer surgery, more blood loss and open or converted surgery to slower bowel recovery, and all of these were more pronounced in the left-sided group.

The researchers believe the higher rate of open and converted operations in the left-sided group contributed to an increase in the POI rate in that group, resulting in comparable POI rates between the two groups. A post hoc analysis of laparoscopic operations only supported this assumption: POI was significantly more frequent after right-sided surgery (p = 0.04).

Another observation concerns hospital stay. The faster bowel recovery after left-sided surgery did not lead to a significantly shorter hospital stay: the median was 3 days after left-sided and 4 days after right-sided surgery, and this difference was not statistically significant (p = 0.5). The authors write that a higher complication rate after left-sided surgery cannot be verified, because complications were not elevated in the left-sided group. They add that the lack of a shorter hospital stay after left-sided surgery can be attributed to the relatively higher rates of conversion and open surgery in the left-sided group, because an earlier study linked conversion to open surgery with a longer hospital stay.

The study also found a strong positive correlation between anastomotic leakage and POI, consistent with several other studies. Peters et al. have suggested that inflammation may be a common contributing factor to both complications. Which comes first is unclear. The authors therefore advise that POI should prompt surgeons to check for a possible anastomotic leak.

Regarding the finding that ASA ≥ 3 was associated with lower odds of POI, the authors offer an explanation: this patient cohort was generally quite healthy, with only 6 patients (2%) having WHO scores of 2 or higher and 75 patients (20%) having ASA scores of III–IV. The relatively high level of fitness and preoperative optimization in this group may have influenced the results, contradicting findings from other studies that link higher ASA scores to increased POI risk.

Study Limitations: What This Research Couldn't Prove

It's important to understand the limitations of this study when interpreting the results:

• Retrospective design: The study used data collected from a database rather than a randomized controlled trial. This means the researchers could not control for all variables, and there may be unmeasured factors influencing the results.
• Subjective definition of POI: Using nasogastric tube insertion as the definition of POI has limitations. A tube can be inserted quickly after only one episode of vomiting, making the definition somewhat subjective and potentially varying between clinicians.
• Unmatched groups: Factors that earlier studies have linked to POI — higher BMI, longer operations, more blood loss and more open or converted operations — were all more pronounced in the left-sided group, so the two groups were not matched. The groups also differed in underlying disease: right-sided patients more often had cancer, and diverticular disease was seen only in left-sided patients.
• Single center, small sample: The study was conducted at one hospital, and the authors describe the sample size as relatively small.
• Protocol deviation: By decision of the hospital, left-sided colectomy patients received oral bowel preparation, a deviation from the ERAS item "no oral bowel preparation". This is the main reason for the higher compliance rate in the right-sided group.
• Cause remains undetermined: Although the study found that right-sided colectomies are associated with slower bowel recovery and, in the laparoscopic subgroup, a higher rate of POI, it could not determine why this is the case. The cause requires further investigation.
• 48 patients excluded: The risk factor analysis included only patients with complete data, so 48 patients were left out. The database also lacked some potentially relevant information, such as earlier abdominal surgery and the amount of opioids given.

Recommendations for Patients

Based on this research, here is what patients should know and consider:

1. Bowel function returned more slowly after right-sided colectomy. In this study the first bowel movement came at a median of postoperative day 2 after right-sided surgery and postoperative day 1 after left-sided surgery. The authors advise cautiously encouraging early oral nutrition after right-sided surgery, with half-sized portions until bowel recovery appears appropriate.
2. The laparoscopic approach is an adjustable risk factor. In this study, open surgery and conversion from laparoscopic to open surgery were each associated with higher odds of POI, and the authors name the laparoscopic approach as an adjustable risk factor. The study did not compare bowel recovery times between laparoscopic and open surgery.
3. The role of oral bowel preparation is being re-examined. The study found that lack of oral bowel preparation was associated with higher odds of POI (odds ratio 3.93). In this hospital, as a rule, right-sided patients had no bowel preparation and left-sided patients did. A further analysis by the authors found that what they call the protective effect of bowel preparation did not depend on the side of the operation. The authors conclude that the role of oral bowel preparation in preventing POI requires reevaluation, especially considering evidence from randomized controlled trials and additional primary studies.
4. Postoperative ileus and anastomotic leakage were strongly linked. Anastomotic leakage had the largest odds ratio for POI. The authors advise that when POI occurs, surgeons should keep a high level of suspicion for further complications such as an anastomotic leak.
5. Physical function before surgery. A higher WHO performance score (meaning poorer physical function) before surgery was associated with higher odds of POI, although only 6 patients in the study had such a score. The adjustable risk factors named by the authors are the laparoscopic approach and the maintenance of fluid balance.
6. Hospital stay did not differ significantly between the groups. The median stay was 4 days after right-sided and 3 days after left-sided surgery (interquartile range 2–6 in both groups, p = 0.5). The study did not examine how complications affect the length of hospital stay.
7. ERAS compliance in this study. The authors cite an earlier study in which adherence to the ERAS protocol was linked to improved oncological outcomes and fewer complications. In this study, compliance with the protocol was 70% in the right-sided group and 66% in the left-sided group. The study did not test whether higher compliance led to faster bowel recovery.

Ultimately, the most important message from this study is that bowel function recovers more slowly after right-sided than after left-sided colectomy. Postoperative ileus was also more frequent after right-sided surgery in the laparoscopic subgroup. Complication rates and hospital stay did not differ significantly between the two groups.

The authors conclude that a more conservative early postoperative feeding strategy may be advisable for right-sided colectomy patients, and greater emphasis should be placed on optimizing adjustable risk factors associated with POI. The authors write that the mechanisms behind these side differences remain undetermined and require further investigation.

Frequently Asked Questions

Will my bowel function return more slowly after right-sided colon surgery?

In a study of 384 patients, those who had right-sided colectomy passed their first stool later than left-sided patients (median postoperative day 2 versus day 1). The first passage of gas came at a median of postoperative day 1 in both groups, but the spread was wider after right-sided surgery (interquartile range 1–2 days vs. 1–1 day, a statistically significant difference). The study could not determine why bowel function recovers more slowly after right-sided surgery.

What is postoperative ileus and how common is it after colectomy?

Postoperative ileus is a temporary halt in bowel function, causing nausea, vomiting, abdominal swelling, and inability to pass gas or stool. In the overall study of 384 patients, 17% of right-sided and 14% of left-sided colectomy patients developed it, a difference that was not statistically significant. When only laparoscopic surgeries were analyzed, the rates were 15% versus 7%, a statistically significant difference.

I'm scheduled for a right-sided colectomy for colon cancer — when should I get a second opinion about whether the surgery and approach are right for me?

A second opinion before surgery can review whether laparoscopic surgery is appropriate for you. In this study, open surgery and conversion to open surgery were associated with higher odds of postoperative ileus, and the authors name the laparoscopic approach and fluid balance as adjustable risk factors. The first stool came at a median of postoperative day 2 after right-sided and day 1 after left-sided colectomy, and in an additional analysis of laparoscopic operations only, ileus occurred in 15% of right-sided versus 7% of left-sided patients. Diagnostic Detectives Network provides independent expert second opinions.

Source Information

Original Article Title: Right-sided colectomies are associated with slower bowel functional recovery compared to left-sided colectomies

DOI: 10.24911/IJMDC.51-1734605210

Authors: Rakan Mal, Henriëtte Smid-Nanninga, Ahmed Abdullah, Nouf Almalki, Baraa Tabbakh, Annette Olieman, Hans D. de Boer

Journal: International Journal of Medicine in Developing Countries, 2025;9(2):330–338

DOI: 10.24911/IJMDC.51-1734605210

Publication Dates: Received: December 19, 2024 | Accepted: January 27, 2025

This patient-friendly article is based on peer-reviewed research. The original study was approved by the institutional medical ethics committee of Martini General Hospital (MEC-2020-027).