Abstract

Background

Colorectal resection through a midline laparotomy is a commonly performed surgical procedure to treat various bowel conditions. The typical postoperative hospital stay after this operation is 6 to 10 days. The main factors hindering early recovery and discharge are thought to include postoperative pain and delayed return of bowel function.

Continuous infusion of a local anaesthetic into tissues surrounding the surgical incision via a multi‐lumen indwelling wound catheter placed by the surgeon prior to wound closure may reduce postoperative pain, opioid consumption, the time to return of bowel function, and the length of hospital stay.

Objectives

To evaluate the efficacy and adverse events of continuous local anaesthetic wound infusion for postoperative pain after midline laparotomy for colorectal resection in adults.

Search methods

We searched the CENTRAL, MEDLINE and Embase databases to January 2019 to identify trials relevant to this review. We also searched reference lists of relevant trials and reviews for eligible trials. Additionally, we searched two clinical trials registers for ongoing trials.

Selection criteria

We considered randomised controlled trials (including non‐standard designs) or quasi‐randomised controlled trials comparing continuous wound infusion of a local anaesthetic versus a placebo or a sham after midline laparotomy for colorectal resection in adults. We did not compare continuous local anaesthetic wound infusion to other techniques, such as transverse abdominis plane block or thoracic epidural analgesia. We allowed non‐randomised analgesic co‐interventions carried out equally in the intervention and control groups.

Data collection and analysis

Two review authors independently identified trials for inclusion and assessed their quality using the Cochrane 'Risk of bias' tool. We extracted data using standardised forms, including pain at rest and on movement (10‐point scale), opioid consumption via a patient‐controlled analgesia (PCA) system (mg morphine equivalent), postoperative opioid‐related adverse events, the time to rescue analgesia, the time to first flatus and to first bowel movement, the time to ambulation, the length of hospital stay, serious postoperative adverse events, and patient satisfaction. We quantitatively synthesised the data by meta‐analysis. We summarised and graded the certainty of the evidence for critical outcomes using the GRADEpro tool and created a 'Summary of findings' table.

Main results

This review included six randomised controlled trials that enrolled a total of 564 adults undergoing elective midline laparotomy for colorectal resection comparing continuous wound infusion of a local anaesthetic to a normal saline placebo. Due to 23 post‐randomisation exclusions, a total of 541 participants contributed data to the analysis of at least one outcome (local anaesthetic 268; control 273). Most participants were aged 55 to 65 years, with normal body mass index and low to moderate anaesthetic risk (American Society of Anesthesiologists class I‐III). Random sequence generation, allocation concealment, and blinding were appropriately carried out in most trials. However, we had to downgrade the certainty of the evidence for most outcomes due to serious study limitations (risk of bias), inconsistency, indirectness, imprecision and reporting bias.

Primary outcomes

On postoperative day 1, pain at rest (mean difference (MD) −0.59 (from 3.1), 95% confidence interval (CI) −1.12 to −0.07; 5 studies, 511 participants; high‐certainty evidence), pain on movement (MD −1.1 (from 6.1), 95% CI −2.3 to −0.01; 3 studies, 407 participants; low‐certainty evidence) and opioid consumption via PCA (MD −12 mg (from 41 mg), 95% CI −20 to −4; 6 studies, 528 participants; moderate‐certainty evidence) were reduced in the local anaesthetic group compared to the control group.

Secondary outcomes

There was a reduction in the time to first bowel movement (MD −0.67 from 4.4 days, 95% CI −1.17 to −0.17; 4 studies, 197 participants; moderate‐certainty evidence) and the length of hospital stay (MD −1.2 from 7.4 days, 95% CI −2.0 to −0.3; 4 studies, 456 participants; high‐certainty evidence) in the local anaesthetic group compared to the control group.

There was no evidence of a difference in any serious postoperative adverse events until hospital discharge (RR 1.04, 95% CI 0.68 to 1.58; 6 studies, 541 participants; low‐certainty evidence) between the two study groups.

Authors' conclusions

After elective midline laparotomy for colorectal resection, continuous wound infusion of a local anaesthetic compared to a normal saline placebo reduces postoperative pain at rest and the length of hospital stay, on the basis of high‐certainty evidence. This means we are very confident that the effect estimates for these outcomes lie close to the true effects. There is moderate‐certainty evidence to indicate that the intervention probably reduces opioid consumption via PCA and the time to first bowel movement. This means we are moderately confident that effect estimates for these outcomes are likely to be close to the true effects, but there is a possibility that they are substantially different. The intervention may reduce postoperative pain on movement, however, this conclusion is based on low‐certainty evidence. This means our confidence in the effect estimate is limited. The true effect may be substantially different from the estimate of the effect. There is low‐certainty evidence to indicate that the intervention may have little or no effect on the rates of any serious postoperative adverse events until hospital discharge. High‐quality randomised controlled trials to evaluate the intervention with a focus on important clinical and patient‐centred outcomes are needed.

Author(s)

Sophie S Liang, Andrew J Ying, Eshan T Affan, Benedict F Kakala, Giovanni FM Strippoli, Alan Bullingham, Helen Currow, David W Dunn, Zeigfeld Yu‐Ting Yeh

Abstract

Plain language summary

Continuous delivery of a local anaesthetic around the wound to treat pain after bowel surgery through a vertical cut in the abdomen

Background

People with bowel disease can be treated with surgery to remove a part of the bowel (colorectal resection). A long vertical cut in the abdomen (midline laparotomy) is often required. Recovery after this type of surgery can be slow and painful. Continuous injection of a local anaesthetic (numbing a specific area of the body, e.g. around the wound) may reduce pain after this type of surgery. The local anaesthetic may also reduce the amount of morphine‐like pain killers required and side effects related to these medications. This could mean a shorter recovery time for the patient and earlier discharge from the hospital.

Study characteristics

We searched for clinical trials to January 2019 looking at the benefits and harms of continuous injection of a local anaesthetic after surgery to remove the bowel through a vertical cut in the abdomen. We looked for trials comparing local anaesthetic to an inactive substance (placebo) such as salty water (normal saline). We found six clinical trials including 541 participants. Most participants were aged 55 to 65 years, of varying health status from fit and healthy to having a severe systemic disease (a disease that affects the whole body).

Key findings

In people who received a local anaesthetic, pain at rest, pain on movement, and requirement for morphine‐like pain killers were reduced on the first day after surgery compared to people who received an inactive substance.

People who received a local anaesthetic also opened their bowels about half a day earlier and were discharged from hospital about a day earlier compared to people who received an inactive substance.

We did not find a difference between people who received a local anaesthetic and those who received an inactive substance in the rates of any serious complications after surgery until hospital discharge.

Certainty of evidence

We rated the certainty of the evidence from studies using four levels: high, moderate, low, very low. Reasons for downgrading the certainty of the evidence included limitations problems with the design of the studies, missing data, differences between trials and how the outcomes were measured, and the small number of participants. We need more high‐quality trials to evaluate this treatment, especially its effects on recovery after surgery, side effects and complications.

We rated the certainty of the evidence for pain after surgery at rest and the length of hospital stay as high, meaning that we are very confident in the findings about the effects of the treatment on these outcomes. We rated the certainty of the evidence for the requirement for morphine‐like pain killers and the time until the first bowel movement as moderate. This means that we are moderately confident in the findings about the effects of the treatment on these outcomes. We rated the certainty of the evidence for pain after surgery on movement and the rates of any serious complications after surgery until hospital discharge as low, meaning that we have limited confidence in the findings about the effects of the treatment on these outcomes.

Author(s)

Sophie S Liang, Andrew J Ying, Eshan T Affan, Benedict F Kakala, Giovanni FM Strippoli, Alan Bullingham, Helen Currow, David W Dunn, Zeigfeld Yu‐Ting Yeh

Reviewer's Conclusions

Authors' conclusions 

Implications for practice 

For clinicians

In adults undergoing elective midline laparotomy for colorectal resection, continuous wound infusion of a local anaesthetic compared to a normal saline placebo probably has beneficial effects on pain and recovery when used as a component of multimodal management of postoperative pain.

The intervention reduces postoperative pain at rest and the length of hospital stay (high‐certainty evidence), probably reduces postoperative opioid consumption via PCA and the time to first bowel movement (moderate‐certainty evidence), and may reduce pain on movement (low‐certainty evidence). The intervention may have little or no effect on the rates of any serious postoperative adverse events, including death by any cause, pulmonary complications, venous thromboembolic complications, wound catheter‐related complications, local anaesthetic systemic toxicity, myocardial infarction, or renal impairment (low‐certainty evidence). The reasons for downgrading the certainty of the evidence included risk of bias relating to study design or missing data, inconsistency between trials, indirectness of outcome assessment, and imprecision of the estimates of effect.

The findings of our review are most applicable to adults undergoing elective midline laparotomy for resection of colorectal cancer, as those undergoing the surgery for other bowel conditions such as inflammatory bowel disease were excluded from two of six trials, although the remaining four trials did not restrict the indication for surgery. The findings may not be applicable to adults undergoing emergency surgery for treatment of acute bowel pathologies.

For patients

Continuous injection of a local anaesthetic into the wound, compared to an inactive substance such as salty water (normal saline), reduces pain at rest and leads to earlier hospital discharge after an elective surgery to remove a part of the bowel through a long vertical cut in the abdomen. It probably reduces the requirement for morphine‐like pain killers and leads to earlier bowel movement, and may reduce pain on movement. It does not appear to affect the rates of any serious complications, although we have limited confidence in this result. The reasons for downgrading the certainty of the evidence included limitations related to study design or missing data, inconsistency between trials, indirectness in the way the outcomes were measured in some trials, and imprecise results due to the small number of participants.

The findings of our review are most relevant to adults electively having this type of surgery to treat bowel cancer, as those having the surgery to treat other bowel conditions such as inflammatory bowel disease were excluded from two of six trials, although the remaining four trials did not restrict the reason for needing surgery. The findings may not be relevant to adults needing to have this type of surgery in an emergency.

For policy makers and funders of the intervention

Overall, our review supports the use of continuous local anaesthetic wound infusion as a component of a multimodal management strategy for postoperative pain after elective midline laparotomy for colorectal resection, based on high‐certainty evidence that the intervention reduces pain at rest and the length of hospital stay, and moderate‐certainty evidence that the intervention probably reduces opioid consumption via PCA and the time to first bowel movement. In addition, our review found low‐certainty evidence that the intervention may reduce pain on movement. The intervention does not appear to affect the rates of any serious postoperative adverse events, although we have limited confidence in this result. Ongoing attention and vigilance must be applied to monitor serious postoperative adverse events.

Implications for research 

General

There are a number of areas to be addressed by further research. High‐quality randomised controlled trials are necessary to evaluate the effectiveness of continuous local anaesthetic wound infusion after midline laparotomy for colorectal resection compared to a placebo or sham, or to an alternative method, such as transverse abdominis plane block or thoracic epidural analgesia. In addition, the optimal implementation of continuous wound infusion in terms of number and location of wound catheter(s), choice and dose of analgesic agent(s), and infusion programme needs to be established. Subgroup analyses suggested that preperitoneal placement of the wound catheter and delivery of a bolus prior to commencing continuous wound infusion may potentially increase the efficacy of the intervention. This warrants further investigation through high‐quality randomised controlled trials. Health economic evaluations of continuous local anaesthetic wound infusion are warranted to balance the current high cost of wound infusion devices against the economic benefits of potentially fewer adverse events and faster recovery.

Study design

• Follow guidance on study design provided by the CONSORT statement (Schulz 2010).
• Consider a stratified design with predefined subgroup analyses to evaluate the intervention in different settings (e.g. emergency versus elective surgery, open versus laparoscopic‐assisted approach) and participants (e.g. by age, body mass index, risk factors for postoperative opioid‐related adverse events).
• Clearly define the non‐randomised multimodal analgesic regimen provided. The regimen should be based on current best practice.
• Consider novel study designs, such as a platform trial design, that can enable efficient comparison of multiple adaptive treatment groups in a heterogenous population (Berry 2015).
• Adopt strategies to mitigate the study limitations affecting previous trials as extensively outlined in this review, including: small sample size, attrition bias, reporting bias, information bias, industry bias.

Outcome measurement and reporting

• Include the following outcomes: daily pain score at rest and with movement, daily opioid consumption, rates of postoperative opioid‐related adverse events (e.g. nausea or vomiting, ileus, urinary retention, pruritus, sedation, respiratory depression, sleep disturbance), the time to first flatus, the time to first bowel movement, the time to ambulation, the length of hospital stay, patient satisfaction.
• If other forms of opioids are used concurrently with an opioid PCA system as a part of the multimodal analgesia regimen, total opioid consumption should be included as an outcome measure in addition to PCA opioid consumption.
• Closely monitor and record rates of adverse events and complications, including: potential treatment complications (e.g. local anaesthetic toxicity, wound catheter injury), wound complications (e.g. laparotomy wound infection, laparotomy wound breakdown), surgical complications (e.g. anastomotic leak, intra‐abdominal infection), other serious postoperative adverse events (e.g. pulmonary complication, myocardial infarction, renal failure, thromboembolic complications), mortality.
• Consider inclusion of health economic outcome measures, such as cost of hospitalisation and interventions.
• Consider medium‐ to long‐term outcomes such as return to work, functional recovery and development of chronic pain.
• Clearly state the definitions and methods of assessment for all outcomes.
• Report all specified outcomes for all treatment groups at baseline and all assessment intervals with appropriate summary statistics, including estimates of effect (e.g. mean, median) and precision (e.g. standard deviation, range, interquartile ranges, confidence interval). Consider including this information in an appendix if unable to be included in the primary publication or depositing data sets in an appropriate public data repository.
• Avoid multiple publications of the same study.

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