Routine abdominal drainage for uncomplicated liver resection
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To assess the benefits and harms of routine abdominal drainage in uncomplicated liver resections.
Background
Elective liver resection is performed mainly for benign and malignant liver tumours (Belghiti 1993). The other main reason for liver resection is living donor liver resection (Bombuy 2004). The malignant tumours may arise primarily within the liver (hepatocellular carcinoma and cholangiocarcinoma) or may be metastases from malignancies of other organs (Belghiti 1993; Fong 1996). More than 1000 elective liver resections are performed annually in the United Kingdom alone (HES 2005).
The liver resections could be anatomical resection (resection of Couinaud segments) or can be non‐anatomic (wedge resections) (Liu 2004). The anatomical liver resections include right hemi‐hepatectomy (Couinaud segments 5‐8 ±1), left hemi‐hepatectomy (segments 2‐4 ±1), right trisectionectomy (segments 4‐8 ±1), left trisectionectomy (segments 2‐5, 8 ±1), right anterior sectionectomy (segments 5,8), right posterior sectionectomy (segments 6,7), left medial sectionectomy (segment 4), left lateral sectionectomy (segments 2,3), segmentectomy (any segment) and bisegmentectomy (any 2 segments in continuity) (Strasberg 2000). Although every liver resection is considered major surgery, only resection of three or more segments is a major liver resection (Belghiti 1993).
Traditionally, after liver resection, a prophylactic drain is placed in the sub‐phrenic space close to the resection surface (Schwartz 1997). The main reasons for inserting a drain after hepato‐biliary surgery are (i) prevention of sub‐phrenic or sub‐hepatic fluid collection, (ii) identification and monitoring of post‐operative bleeding (Bona 1994), (iii) identification and drainage of any bile leak (Sarr 1987; Bona 1994), and (iv) prevent the accumulation of ascitic fluid (which is common after resection of cirrhotic liver, particularly in those patients with portal hypertension) (Fuster 2004).
Surgical drains may either be open or closed. An open drain is when an artificial conduit is left in the wound to allow drainage of fluids to the exterior (eg, corrugated drain; Penrose drain; Yeates drain). Closed drains allow drainage of fluids through a tube into a sealed container. Closed drains may either be suction drains (eg, Redon drain) or passive (gravity assisted) drains (eg, Robinson drain).
While some authors found that using a drain reduced the ascitic leak (Fuster 2004), others have found that there was no significant difference in the complication rates whether drain is used or not (Fong 1996; Aldameh 2005). However, other authors found that using a drain increased the morbidity rates including chest infection (Liu 2004), wound infection (Liu 2004), sub‐phrenic collections (Belghiti 1993), and ascitic leak (Liu 2004). The drain did not detect any of the bile leaks and intra‐abdominal bleeding in a study on the use of drain in liver resections (Liu 2004). Drain‐site infection is also a complication of using a drain (Fong 1996; Liu 2004). Another feared complication of using a drain is the potential cancer seedling along the drain tract (Fong 1996).
Thus the use of abdominal drain in liver resections is a controversial issue. We have not been able to identify any meta‐analyses or systematic reviews comparing routine abdominal drainage versus no abdominal drainage in uncomplicated liver resections.
Objectives
To assess the benefits and harms of routine abdominal drainage in uncomplicated liver resections.
Methods
Criteria for considering studies for this review
Types of studies
Only randomised clinical trials (irrespective of language, blinding, or publication status) will be considered for this review.
Quasi‐randomised studies (where the method of allocating participants to a treatment are not strictly random, eg, date of birth, hospital record number, alternation), cohort studies, and case‐control studies will not be considered for this review.
Types of participants
Adult patients who have undergone uncomplicated elective liver resection for any indication. We will exclude trials with patients with complicated liver resection, emergency liver resection, and those with biliary‐enteric anastomoses as these conditions constitute a different subset of patients, although the main reason for keeping the drain in these groups of patients is also to detect leak of blood or bile or intestinal content.
Types of interventions
We will include only trials comparing abdominal drainage versus no drainage (irrespective of the type of the drain; minor or major liver resection).
Trials comparing two types of drains will also be included in this review.
Co‐interventions will be allowed provided they are used equally in the intervention arms.
Types of outcome measures
Primary outcomes
(1) Mortality at maximal follow‐up.
(2) Re‐operations.
(3) Additional procedures for subhepatic collection
(a) Surgical drainage.
(b) Radiological drainage requiring insertion of drain.
(c) Radiological drainage requiring percutaneous aspiration.
Secondary outcomes
(4) Infected abdominal collections (however defined by authors).
(5) Wound dehiscence.
(6) Wound infection (as reported by authors):
(6a) Main wound site.
(6b) Drain site.
(7) Biliary fistula.
(8) Ascitic leak (however defined by authors).
(9) Chest infections.
(10) Other respiratory complications (pleural effusion, pneumothorax).
(11) Tumour recurrence at drain site.
(12) Hospital stay.
Search methods for identification of studies
We will search The Cochrane Hepato‐Biliary Group Controlled Trials Register, theCochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded (Royle 2003). We have given the preliminary search strategies in Table 1 with the timespan for the searches. As the review progresses, we will improve the search strategies if necessary.
| Database | Period | Search strategy used |
| The Cochrane Hepato‐Biliary Group Controlled Trials Register | The date will be given when the search is performed. | drain* AND (((liver OR hepat*) AND (segmentectomy OR resection)) OR hepatectomy) |
| Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library | Latest issue. | #1 MeSH descriptor Drainage explode all trees in MeSH products |
| MEDLINE | January 1950 to the date when the search will be performed. | ((("Liver"[MeSH] OR "Liver Neoplasms"[MeSH] OR "Liver Diseases"[MeSH] OR "Adenoma, Liver Cell"[MeSH] OR "Carcinoma, Hepatocellular"[MeSH] OR liver OR hepat*) AND (segmentectomy OR resection)) OR hepatectomy OR "Hepatectomy"[MeSH]) AND ("Drainage"[MeSH] OR drain*) AND ((randomized controlled trial [pt] OR controlled clinical trial [pt] OR randomized controlled trials [mh] OR random allocation [mh] OR double‐blind method [mh] OR single‐blind method [mh] OR clinical trial [pt] OR clinical trials [mh] OR ("clinical trial" [tw]) OR ((singl* [tw] OR doubl* [tw] OR trebl* [tw] OR tripl* [tw]) AND (mask* [tw] OR blind* [tw])) OR (placebos [mh] OR placebo* [tw] OR random* [tw] OR research design [mh:noexp]) NOT (animals [mh] NOT human [mh])) |
| EMBASE | January 1974 to the date when the search will be performed. | 1. drain$ OR SURGICAL‐DRAINAGE.DE. |
| Science Citation Index Expanded (http://portal.isiknowledge.com/portal.cgi?DestApp=WOS&Func=Frame) | 1970 to the date when the search will be performed. | #1 TS=(liver OR hepat*) |
We will also search the references of the identified trials to identify further relevant trials.
Data collection and analysis
Trial selection and extraction of data
Both authors independently of each other will identify the trials for inclusion. We will also list the excluded studies with the reasons for the exclusion.
Both authors will independently extract the following data:
(1) Year and language of publication.
(2) Country.
(3) Year of study.
(4) Inclusion and exclusion criteria.
(5) Sample size.
(6) Population characteristics such as age and sex ratio.
(7) Type of drain used.
(8) Whether drain was brought out through main wound or separate wound.
(9) Preoperative antibiotics.
(10) Type of dissection.
(11) Management of the raw surface.
(12) Criteria for removing the drain.
(13) Outcomes (mentioned above).
(14) Methodological quality (described below).
Any unclear or missing information will be sought by contacting the authors of the individual trials. If there is any doubt whether the trials share the same patients ‐ completely or partially (by identifying common authors and centres), the authors of the trials will be contacted to clarify whether the trial has been duplicated.
We will resolve any differences in opinion through discussion.
Assessment of methodological quality
The authors will assess the methodological quality of the trials independently, without masking of the trial names. The authors will follow the instructions given in Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2005). Due to the risk of biased overestimation of intervention effects in randomised trials with inadequate methodological quality (Schulz 1995; Moher 1998; Kjaergard 2001), we will look at the influence of methodological quality of the trials on the results by evaluating the reported randomisation and follow‐up procedures in each trial. If information is not available in the published trial, we will contact the authors in order to assess the trials correctly. We will assess generation of allocation sequence, allocation concealment, blinding, and follow‐up.
Generation of the allocation sequence
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Adequate, if the allocation sequence was generated by a computer or random number table. Drawing of lots, tossing of a coin, shuffling of cards, or throwing dice will be considered as adequate if a person who was not otherwise involved in the recruitment of participants performed the procedure.
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Unclear, if the trial was described as randomised, but the method used for the allocation sequence generation was not described.
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Inadequate, if a system involving dates, names, or admittance numbers were used for the allocation of patients. These studies are known as quasi‐randomised and will be excluded from the review.
Allocation concealment
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Adequate, if the allocation of patients involved a central independent unit, on‐site locked computer, or sealed envelopes.
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Unclear, if the trial was described as randomised, but the method used to conceal the allocation was not described.
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Inadequate, if the allocation sequence was known to the investigators who assigned participants. Such studies will be excluded.
Blinding
Double blinding will not be assessed since we expect that there will be no double‐blind trials. However, we will record whether any of the outcomes were assessed by a blinded observer or blinded assessor.
Follow‐up
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Adequate, if the numbers and reasons for dropouts and withdrawals in all intervention groups were described or if it was specified that there were no dropouts or withdrawals.
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Unclear, if the report gave the impression that there had been no dropouts or withdrawals, but this was not specifically stated.
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Inadequate, if the number or reasons for dropouts and withdrawals were not described.
Statistical methods
We will perform the meta‐analyses according to the recommendations of The Cochrane Collaboration (Higgins 2005). We will use the software package RevMan Analyses (RevMan 2003). For dichotomous variables, we will calculate the odds ratio with 95% confidence interval. We will use a random‐effects model (DerSimonian 1986) and a fixed‐effect model (DeMets 1987). In case of discrepancy between the two models we will report both results; otherwise we will report only the results from the fixed‐effect model. Heterogeneity will be explored by chi‐squared test with significance set at P value 0.10, and the quantity of heterogeneity will be measured by I2 (Higgins 2002).
We will adopt the 'available‐case analysis' (Higgins 2005) The analysis will be performed on an intention‐to‐treat basis (Newell 1992). In case we find 'zero‐event' trials, we will perform a sensitivity analysis with and without empirical continuity correction factors as suggested by Sweeting et al (Sweeting 2004). We will also report the risk difference because of its immunity to 'zero‐event' trials.
Subgroup analysis
We will perform the following subgroup analyses:
‐ trials with high (adequate generation of allocation sequence and allocation concealment) compared to trials with low methodological quality (unclear generation of allocation sequence or unclear allocation concealment).
‐ drainage in major liver resection compared to minor liver resections.
‐ liver resection in cirrhotic livers compared to non‐cirrhotic livers.
‐ open compared to closed drains.
‐ suction compared to passive drains.
‐ trials that use routine antibiotic prophylaxis compared to those that do not use routine antibiotic prophylaxis.
Bias exploration
We will use a funnel plot to explore publication bias and other bias (Egger 1997; Macaskill 2001). Asymmetry in funnel plot of trial size against treatment effect will be used to assess this bias. We will perform linear regression approach described by Egger et al (Egger 1997) to determine the funnel plot asymmetry.
| Database | Period | Search strategy used |
| The Cochrane Hepato‐Biliary Group Controlled Trials Register | The date will be given when the search is performed. | drain* AND (((liver OR hepat*) AND (segmentectomy OR resection)) OR hepatectomy) |
| Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library | Latest issue. | #1 MeSH descriptor Drainage explode all trees in MeSH products |
| MEDLINE | January 1950 to the date when the search will be performed. | ((("Liver"[MeSH] OR "Liver Neoplasms"[MeSH] OR "Liver Diseases"[MeSH] OR "Adenoma, Liver Cell"[MeSH] OR "Carcinoma, Hepatocellular"[MeSH] OR liver OR hepat*) AND (segmentectomy OR resection)) OR hepatectomy OR "Hepatectomy"[MeSH]) AND ("Drainage"[MeSH] OR drain*) AND ((randomized controlled trial [pt] OR controlled clinical trial [pt] OR randomized controlled trials [mh] OR random allocation [mh] OR double‐blind method [mh] OR single‐blind method [mh] OR clinical trial [pt] OR clinical trials [mh] OR ("clinical trial" [tw]) OR ((singl* [tw] OR doubl* [tw] OR trebl* [tw] OR tripl* [tw]) AND (mask* [tw] OR blind* [tw])) OR (placebos [mh] OR placebo* [tw] OR random* [tw] OR research design [mh:noexp]) NOT (animals [mh] NOT human [mh])) |
| EMBASE | January 1974 to the date when the search will be performed. | 1. drain$ OR SURGICAL‐DRAINAGE.DE. |
| Science Citation Index Expanded (http://portal.isiknowledge.com/portal.cgi?DestApp=WOS&Func=Frame) | 1970 to the date when the search will be performed. | #1 TS=(liver OR hepat*) |
