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Peritoneal drainage versus laparotomy as initial surgical treatment for perforated necrotizing enterocolitis or spontaneous intestinal perforation in preterm low birth weight infants

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Authors

Shripada C Rao1, Laxman Basani2, Karen Simmer1, Naeem Samnakay3, Girish Deshpande4

Background - Methods - Results - Characteristics of Included Studies - References - Data Tables & Graphs


1Neonatal Care Unit, King Edward Memorial Hospital for Women and Princess Margaret Hospital for Children, Subiaco, Australia [top]
2Neonatology, Royal North Shore Hospital, St. Leonards, Australia [top]
3Department of Surgery, Princess Margaret Hospital, Subiaco, Australia [top]
4Neonatal Pediatrics, Nepean Hospital Sydney and University of Sydney, Kingswood, Australia [top]

Citation example: Rao SC, Basani L, Simmer K, Samnakay N, Deshpande G. Peritoneal drainage versus laparotomy as initial surgical treatment for perforated necrotizing enterocolitis or spontaneous intestinal perforation in preterm low birth weight infants. Cochrane Database of Systematic Reviews 2011, Issue 6. Art. No.: CD006182. DOI: 10.1002/14651858.CD006182.pub2.

Contact person

Shripada C Rao

Neonatal Care Unit
King Edward Memorial Hospital for Women and Princess Margaret Hospital for Children
Robert Road
Ward 6B
Subiaco
6008
Australia

E-mail: Shripada.Rao@health.wa.gov.au

Dates

Assessed as Up-to-date: 31 January 2011
Date of Search: 10 July 2010
Next Stage Expected: 31 January 2013
Protocol First Published: Issue 4, 2006
Review First Published: Issue 6, 2011
Last Citation Issue: Issue 6, 2011

History

Date / Event Description
24 October 2008
Amended

Converted to new review format.

Abstract

Background

Standard surgical management of infants with perforated necrotizing enterocolitis (NEC) or spontaneous intestinal perforation (SIP) is laparotomy with the resection of the necrotic or perforated segments of the intestine. Peritoneal drainage is an alternative approach to the management of such infants.

Objectives

To evaluate the benefits and risks of peritoneal drainage compared to laparotomy as the initial surgical treatment for perforated NEC or SIP in preterm infants.

Search methods

Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library 2010, Issue 3), MEDLINE (1966 to July 2010), EMBASE (1980 to July 2010), CINAHL (1982 to July 2010), previous reviews and cross-references were searched. Abstracts of paediatric academic society meetings were also searched (online: 2000 to 2009; handsearching Pediatric Research: 1995 to 2000).

Selection criteria

All randomised or quasi-randomised controlled trials in preterm (< 37 weeks gestation), low birth weight (< 2500 g) infants with perforated NEC or SIP allocated to peritoneal drainage or laparotomy as initial surgical treatment.

Data collection and analysis

Data were excerpted from the trial reports and analysed according to the standards of the Cochrane Neonatal Review Group.

Results

Only two randomised controlled trials (RCT) met the eligibility criteria. Overall, no significant differences were seen between the peritoneal drainage and laparotomy groups regarding the incidence of mortality within 28 days of the primary procedure (28/90 versus 30/95; typical relative risk (RR) 0.99, 95% CI 0.64 to 1.52; N = 185, two trials); mortality by 90 days after the primary procedure (typical RR 1.05, 95% CI 0.71 to 1.55; N = 185, two trials) and the number of infants needing total parenteral nutrition for more than 90 days (typical RR 1.18, 95% CI 0.72 to 1.95; N = 116, two trials). Nearly 50% of the infants in the peritoneal drainage group could avoid the need for laparotomy during the study period (44/90 versus 95/96; typical RR 0.49, 95% CI 0.39 to 0.61; N = 186, two trials). One study found that the time to attain full enteral feeds in infants less than/or equal to 1000 g was prolonged in the peritoneal drainage group (mean difference (MD) 20.77, 95% CI 3.62 to 37.92).

Authors' conclusions

Evidence from two RCTs suggests no significant benefits or harms of peritoneal drainage over laparotomy. However, due to the very small sample size, clinically significant differences may have easily been missed. No firm recommendations can be made for clinicians. Large multicentre randomised controlled trials are needed to address this question definitively.

Plain language summary

Peritoneal drainage versus laparotomy as initial surgical treatment for perforated necrotizing enterocolitis or spontaneous intestinal perforation in preterm low birth weight infants

Intestinal perforation is a very serious condition in very premature babies. Standard treatment of intestinal perforation is the surgical opening of the abdomen and removal of the unhealthy or dead intestine. Insertion of a drain into the abdomen instead of surgical opening has been tried to treat this condition. This review did not find any significant advantages or harms of insertion of the drain over surgically opening the abdomen; however, there is too little evidence to fully understand the risks and benefits of this approach.

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Background

Description of the condition

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in the preterm infant (Tudehope 2005). Bell staging criteria with the Walsh and Kliegman modification allow uniformity of diagnosis and treatment based on severity of illness (Bell 1978; Walsh 1986). Stage I is defined as suspected NEC, manifesting as feeding intolerance, abdominal distention and occult or frank blood in the stool; Stage II is definite NEC, presenting with marked abdominal distention, blood in the stool and pneumatosis intestinalis on radiograph; Stage III is advanced NEC, with impending or proven perforation in addition to pneumatosis intestinalis in a critically ill baby with metabolic derangement (Walsh 1986). The incidence of significant NEC (greater than/or equal to stage 2) is 5% to 12% in very low birth weight (< 1500 g) infants (Stoll 1994; Horbar 2002; Fitzgibbons 2009), with a higher incidence at lower length of gestation and birth weight. NEC is characterised by variable damage to the intestinal tract, ranging from mucosal injury to full-thickness necrosis and perforation. The areas most commonly affected are the terminal ileum and proximal ascending colon. The pathogenesis of NEC is multifactorial (Kanto 1985; Uauy 1991).

Isolated intestinal perforation or spontaneous intestinal perforation (SIP), on the other hand, is thought to be a distinct clinical entity that is different from NEC (Pumberger 2002; Tarrado 2005). The onset of illness in SIP is usually significantly earlier than in NEC (Okuyama 2002). Presence of free intraperitoneal air in the absence of pneumatosis intestinalis on preoperative x-rays suggest the possibility of SIP. SIP is usually not associated with significant metabolic derangement such as metabolic acidosis, hypotension, neutropenia, thrombocytopenia and hyponatraemia (Tepas 2006; Nguyen 2007). At operation, SIP is usually located in the terminal ileum in an antimesenteric position, with the rest of the bowel being normal.

However, it may not be possible to definitely distinguish between perforated NEC and SIP during the preoperative period and often these two conditions are described together as perforated NEC and treated similarly. Hence, the term 'perforated NEC' is used by the majority of the published studies to include both conditions.

Reported mortality rates for preterm infants with perforated NEC range from 10% to 50%, with lower gestational age groups carrying a higher risk (Schullinger 1981; Snyder 1997; Blakely 2005; Luig 2005A; Luig 2005; Fitzgibbons 2009). Survivors of significant NEC are at high risk of serious short and long term complications, including neurodevelopmental impairment (Tobiansky 1995; Sonntag 2000; Blakely 2006; Rees 2007; Schulzke 2007). Infants with NEC requiring surgery are at higher risk for neurodevelopmental impairment compared to those who require only medical therapy (Rees 2007; Schulzke 2007).

Description of the intervention

The standard surgical treatment for perforated NEC or SIP is laparotomy (Henry 2008). The principal objectives of laparotomy are to remove gangrenous or perforated bowel and to preserve as much of the intestine as possible. Options include resection of necrotic areas of bowel with enterostomy, resection with primary anastomosis, proximal jejunostomy, the 'clip and drop' technique and 'patch, drain and wait' (Pierro 2005).

Peritoneal drainage on the other hand involves the simple procedure of inserting a Penrose drain into the peritoneal cavity. This is usually done at the bedside in the neonatal intensive care unit under local anaesthesia.

How the intervention might work

The peritoneal drain removes the toxic effluents in the peritoneal cavity such as blood, gas and pus. This decompresses the abdomen and facilitates the stabilisation of the infant. In addition, the unique features of wound healing described in experimental fetal models may play a role in the healing of the gastrointestinal perforation. Fetal wound healing without inflammation and scarring is well documented for humans and appears to be related to intrinsic differences in fetal cells and the extracellular matrix (Longaker 1989). This type of wound healing begins to diminish at the start of the third trimester and does not occur once gestational maturity is attained. These findings would suggest that if the bowel were to heal on its own, it would be less likely to produce scarring and stricture in preterm infants. The ability of the fetal peritoneal cavity to resorb infarcted bowel is well demonstrated by intestinal atresia (Longaker 1991; Adzick 1992; Roh 2001). Peritoneal drainage also avoids the intra and immediate postoperative complications in critically ill very preterm infants undergoing surgery. The other theoretical advantage is the potential for the avoidance of deleterious effects of general anaesthesia on the developing brain (Loepke 2008).

Laparotomy on the other hand allows direct visualisation of the intestines, enabling the surgeon to undertake appropriate procedures such as resection of the gangrenous segment; peritoneal lavage with evacuation of pus, stools and blood; and creation of enterostomies. Removal of gangrenous segments in turn helps control the sepsis and other metabolic derangements.

Why it is important to do this review

Peritoneal drainage was initially introduced in the late 1970s to stabilise the critically ill, extremely low birth weight (ELBW) infant prior to laparotomy (Ein 1977). Subsequently Ein et al (Ein 1990) reported that some of the preterm infants who were treated with peritoneal drainage recovered completely without the need for any laparotomy. Since then, many units have tried peritoneal drainage as either a stabilising or even definitive procedure for perforated NEC or SIP; 95% of the surgeons who responded to a recent survey in the UK used peritoneal drainage for stabilisation and 58% used it as definitive treatment (Rees 2005). A USA study also found that peritoneal drainage was very commonly used for perforated NEC or SIP (Blakely 2006). Many retrospective studies have tried to address the role of peritoneal drainage for perforated NEC and SIP in preterm infants (Cheu 1988; Takamatsu 1992; Snyder 1997; Demestre 2002; Gollin 2003; Lee 2003; Morgan 1994; Dimmitt 2000; Pierro 2003; Romero 2005; Rees 2005; Ibanez 2009). Two RCTs have been published addressing this issue. If peritoneal drainage is as effective as or superior to laparotomy as a treatment of acute cases of perforated NEC or SIP, it will have significant implications for the management of these critically ill infants. Hence we undertook this systematic review to evaluate the benefits and risks of peritoneal drainage compared to laparotomy as the initial surgical treatment of perforated NEC or SIP in preterm infants.

Objectives

To evaluate the benefits and risks of peritoneal drainage compared to laparotomy as the initial surgical treatment for perforated NEC or SIP in preterm and LBW infants.

Subgroup analysis:

  • birthweight less than/or equal to 1000 g versus > 1000 g;
  • gestational age less than/or equal to 30 weeks versus > 30 weeks;
  • preoperative diagnosis of perforated NEC versus SIP.

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Methods

Criteria for considering studies for this review

Types of studies

All randomised or quasi-randomised controlled trials.

Types of participants

Preterm (< 37 weeks gestation) or low birth weight (< 2500 g) neonates with perforated NEC or SIP.

Types of interventions

Peritoneal drainage or laparotomy as initial surgical treatment.

Types of outcome measures

Primary outcomes

Mortality at 28 days, within 90 days of surgery, within six months of surgery, before discharge and at one year corrected age.

Secondary outcomes
  1. Need for parenteral nutrition for greater than three months (chronic) after initial surgery.
  2. Recurrent NEC.
  3. Need for laparotomy any time after the primary procedure.
  4. Need for laparotomy within seven days of the primary surgical intervention.
  5. Need for laparotomy greater than/or equal to seven days after the primary surgical intervention.
  6. Abdominal abscess.
  7. Intestinal fistula: occurring between two loops of intestine (entero-enteric fistula) or intestine and skin (entero-cutaneous fistula) and diagnosed by contrast imaging or operative exploration.
  8. Intestinal stricture: a narrow area of intestine that may lead to bowel obstruction, diagnosed by contrast imaging or operative exploration.
  9. Bladder fistula: abnormal connection between (a) the bladder and the rectum or vagina; or (b) the bladder and the skin.
  10. Time to attain full enteral feeds after the primary procedure (days).
  11. Length of stay in hospital (days).
  12. Neurodevelopmental outcome at 18 to 26 months corrected age.
  13. Cost effectiveness: cost per one patient that has survived until discharge home.

Search methods for identification of studies

We used the standard search strategy of the Cochrane Neonatal Review Group was used.

Electronic searches

We performed electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library 2010, Issue 3), MEDLINE (1966 to July 2010), EMBASE (1980 to July 2010), CINAHL (1982 to July 2010) and previous reviews including the cross-references. Abstracts of paediatric academic society meetings were also searched (online: 2000 to 2009; handsearching Pediatric Research: 1995 to 2000).

The following MeSH terms or text words were used to search the literature: (primary peritoneal drainage OR peritoneal drainage OR laparotomy OR abdominal paracentesis OR abdominal drainage) AND (necrotising enterocolitis OR necrotizing enterocolitis OR NEC OR perforated NEC OR perforated necrotising enterocolitis OR spontaneous intestinal perforation OR isolated intestinal perforation OR SIP AND (infant, newborn/OR infant, low birth weight/OR infant, very low birth weight/OR infant, premature/OR Infant, Premature, Diseases) OR (neonate: OR prematur*: OR newborn) AND (clinical trial OR Randomized Controlled Trials). No language restrictions were applied.

Clinical trial registries were also searched for ongoing or recently completed trials (ClinicalTrials.gov, Controlled-Trials.com External Web Site Policy, and WHO International Clinical Trials Registry Platform (ICTRP) External Web Site Policy.

Searching other resources

Reference lists of published narrative and systematic reviews were also reviewed. The authors of the identified studies were contacted to provide additional information from their studies.

Data collection and analysis

Data regarding clinical outcomes were excerpted from the trial reports by one review author (SR) and checked by the second review author (NS). Data were analysed according to the standards of the Cochrane Neonatal Review Group.

Selection of studies

All randomised and quasi-randomised controlled trials fulfilling the selection criteria. SR and GD screened the titles and abstracts of all the identified studies and obtained full articles for all potentially relevant trials. SR and GD independently assessed the full text of these reports to determine their eligibility for inclusion in the review.

Data extraction and management

SR and GD separately extracted, assessed and coded all data for each study using a form that was designed specifically for this review. Any disagreement was resolved by discussion with NS and KS. NS contacted the trial authors to clarify methodology and to obtain additional information. For each study, final data were entered into RevMan by SR and then checked by GD and NS. Any disagreement was resolved by discussion with KS.

Assessment of risk of bias in included studies

Two review authors (SR and GD) independently assessed the risk of bias for each study using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2008). Any disagreement was resolved by discussion involving KS and NS as the new assessors.

The methodological quality of the studies was assessed and entered into the 'Risk of Bias' table using the following criteria.

  1. Was there adequate sequence generation (checking for possible selection bias)? The method used to generate the allocation sequence in each included study was described as: low risk (any truly random process such as random number table, computerised random number generator); high risk (any nonrandom process, for example odd or even date of birth, hospital or clinic record number); or unclear risk.
  2. Was there adequate allocation concealment (checking for possible selection bias)? The method used to conceal the allocation sequence in each included study was described as: adequate (for example telephone or central randomisation, consecutively numbered sealed opaque envelopes); inadequate (open random allocation, unsealed or non-opaque envelopes, alternation, date of birth); or unclear.
  3. Was there adequate blinding (checking for possible performance bias)? The methods used to blind the personnel from the knowledge of which intervention the participants received: was knowledge of the allocated intervention adequately prevented during the study; and at the time of outcome assessment?
  4. Were incomplete outcome data addressed (checking for possible attrition bias through withdrawals, dropouts, protocol deviations)? If attrition and exclusion were reported: the numbers included in the analysis at each stage (compared with the total number of randomised participants); reasons for attrition or exclusion where reported; and whether missing data were balanced across the groups or were related to outcomes where reported. We assessed the methods as low risk (< 20% missing data); high risk (greater than/or equal to 20% missing data); or unclear risk.
  5. Was there selective reporting bias? The possibility of selective outcome reporting bias was investigated. We assessed the methods as low risk (where it was clear that all of the study's prespecified outcomes and all expected outcomes of interest to the review had been reported); high risk (where not all of the study's prespecified outcomes were reported; one or more reported primary outcomes were not prespecified; outcomes of interest were reported incompletely and so could not be used; study failed to include results of a key outcome that would have been expected to have been reported); or unclear risk.
  6. Were there any other sources of potential bias? Any important concerns we had about other potential sources of bias (for example whether there was a potential source of bias related to the specific study design or whether the trial was stopped early due to some data-dependent process) were described. We assessed whether each study was free of other problems that could put it at risk of bias as: low risk; high risk; or unclear risk.

Measures of treatment effect

We used the standard methods of the Cochrane Neonatal Review Group. For the dichotomous outcomes, we used relative risk (RR) and risk difference (RD) with their 95% confidence intervals. For continuous data, we used the mean difference (MD) and its 95% confidence interval (CI).

Assessment of heterogeneity

We examined the heterogeneity between trial results by inspecting the forest plots. We quantified the impact of heterogeneity in the meta-analysis using a measure of the degree of inconsistency in the studies' results using the I2 statistic.

Data synthesis

Since the patient population and the intervention were similar in both the studies, it was considered appropriate to pool the data. Meta-analysis was done with RevMan 5 software using the fixed-effect model.

Subgroup analysis and investigation of heterogeneity

Planned subgroup analyses

Subgroup analysis was carried out for the prespecified category:

  • birthweight less than/or equal to 1000 g versus > 1000 g.

The subgroup analysis for less than/or equal to 30 weeks versus > 30 weeks gestation could not be carried out because only 10 out of a total of 186 study infants were > 30 weeks gestation.

Another subgroup was added post-hoc: perforated NEC versus SIP. This could not be carried out because neither of the studies stratified the infants based on this preoperative diagnosis.

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Results

Description of studies

After a thorough literature search, 22 possibly eligible studies were identified. After reading all 22 full text articles, 20 were excluded because of the non-randomised nature of the studies; two were included. One ongoing study was also identified by searching ClinicalTrials.gov.

See the following tables for further information: 'Characteristics of Included Studies', 'Characteristics of excluded studies' and 'Characteristics of ongoing studies'.

Included studies

The search identified two studies (Moss 2006; Rees 2008) that met the eligibility criteria for inclusion in the review.

Moss 2006 was a multicentre RCT conducted in 15 centres across USA and Canada.
Objectives

To determine whether primary peritoneal drainage improved survival 90 days postoperatively as compared with laparotomy in preterm very low birth weight infants (< 1500 g) with perforated NEC or SIP.

Population

Preterm infants less than 34 weeks gestation at birth and birth weight less than 1500 g with evidence of perforated necrotizing enterocolitis or SIP were eligible for inclusion. Intestinal perforation was defined as the presence of free intraperitoneal air on abdominal radiographs (96 infants); stool, bile or pus found at abdominal paracentesis (five infants) or clinical evidence of perforation in the joint opinion of the attending surgeon and the neonatologist (16 infants). The investigators did not differentiate between perforated NEC and those with SIP at the time of randomisation. Infants with gastrointestinal anomalies, a previous abdominal operation or bilateral grade four intraventricular haemorrhage were not eligible. A total of 55 were randomised to primary peritoneal drainage and 62 to primary laparotomy. The study infants in both groups were similar with respect to their baseline demographic and clinical characteristics.

Inteventions

Primary peritoneal drainage: infants randomised to primary peritoneal drainage received a 0.6 cm full thickness incision in the right lower quadrant of the abdomen. Stools and pus were expressed manually from the peritoneal cavity, which was then irrigated with warmed normal saline until clear. A long 1/4 inch Penrose drain was placed via the incision in the right lower quadrant. A second drain was placed if the surgeon believed it was needed to provide effective drainage. If the air or fluid re-accumulated, the original drain was manipulated or an additional drain inserted. The protocol allowed, but did not encourage, early laparotomy in infants with persistent metabolic acidosis, haemodynamic instability and respiratory failure.

Primary laparotomy: infants assigned to the laparotomy underwent abdominal exploration through a transverse abdominal incision. All frankly necrotic intestines were resected and stomas created. If evidence of further intestinal necrosis or perforation developed, additional laparotomies were performed.

Outcomes assessed

The primary outcome of interest was mortality 90 days after the intervention. The secondary outcome measures were dependence on total parenteral nutrition 90 days postoperatively and the length of hospital stay for Infants surviving 90 days postoperatively.

Rees 2008 was a multicentre RCT conducted across 31 surgical neonatal units in UK, Europe, Australia, New Zealand and Asia.
Objectives

To determine whether primary peritoneal drainage improved survival and outcomes of extremely low birth weight infants(< 1000 g) with intestinal perforation as compared to laparotomy.

Population

Extremely low birth weight preterm infants (< 1000 g) with evidence of intestinal perforation were eligible. Intestinal perforation was defined as the presence of free intraperitoneal air on abdominal radiographs. Infants with extensive disease as well as those with SIP were included in the study. The investigators stated that they did not differentiate between perforated NEC and SIP because it is difficult to differentiate between them preoperatively. Infants were excluded from the trial if they had: previous episodes of NEC, a previous laparotomy or peritoneal drain, bilateral grade 4 intraventricular haemorrhage or were treated in a neonatal intensive care unit where access to paediatric surgeons was not available. A total of 35 were randomised to primary peritoneal drainage and 34 to primary laparotomy. The study infants in both groups were similar with respect to their baseline demographic and clinical characteristics.

Inteventions

Primary peritoneal drainage: infants randomised to primary peritoneal drainage underwent this procedure at the bedside in the neonatal unit. The paediatric surgeons performed this procedure under local anaesthesia, via an incision made in the right or left lower quadrant of the abdomen. The peritoneal cavity was entered under direct vision and a 1/4 inch soft drain inserted. Irrigation via the drain was not recommended. Infants whose clinical condition was stable continued with peritoneal drainage. Infants with a deteriorating clinical condition were allowed laparotomy at the discretion of the surgeon, after at least 12 hours of being on peritoneal drainage. The criteria for laparotomy were based on worsening of the clinical condition (for example inotrope requirement, respiratory support, decreased urine output, increasing or persistent pneumoperitoneum, palpable mass, increasing abdominal distension or discolouration, and persistent intestinal obstruction).

Primary laparotomy: infants assigned to the laparotomy underwent abdominal exploration either in theatre or in the neonatal unit. The choice of surgery was at the discretion of the operating surgeon.

Outcomes assessed

The primary outcome of interest was survival at one and six months after the intervention. The secondary outcomes were length of hospital stay, dependence on ventilation by one and six months, dependence on parenteral nutrition by one and six months and time to full enteral feeding.

Ongoing studies: a search of ClinicalTrials.gov, Controlled-Trials.com External Web Site Policy, and WHO International Clinical Trials Registry Platform (ICTRP) External Web Site Policy revealed one multicentre RCT which started recruiting from January 2010 (Blakely 2009).

Risk of bias in included studies

Trials were evaluated for their methodological quality in terms of adequacy of sequence generation, concealment of allocation, blinding of intervention and outcome assessment, completeness of follow up and completeness of reporting.Details are given in the table 'Characteristics of Included Studies' and the 'Risk of bias' table.

In the Moss 2006 trial, infants were randomised to receive primary peritoneal drainage or laparotomy within permuted blocks of four, with the block size unknown to the investigators. A computerised random number generator was used to generate the allocation sequence. Allocation concealment was maintained by means of sequentially numbered, sealed opaque envelopes for each stratum; randomisation was stratified according to birthweight (< 1000 g; 1001 to 1499 g). Being a surgical intervention, it was not possible to mask the intervention. The statisticians were blinded to the interventions. All infants were followed and they were accounted for at the final evaluation.All the study's prespecified outcomes were reported.

In the Rees 2008 trial, infants were randomised to receive primary peritoneal drainage or laparotomy by weighted minimisation. Minimisation criteria used were: weight at enrolment (< 800 g, 800 to 1000 g), gestational age (less than/or equal to 26 weeks, > 26 weeks), platelet count (< 100, 000 or transfused, greater than/or equal to 100, 000), mechanical ventilation required (yes, no), inotropic support required (yes, no), facilities for onsite laparotomy (that is ambulance transfer required: yes, no), and geographical location (10 groups). This minimised the chance that patient management differed preoperatively and postoperatively between the allocated groups. The method used to generate the allocation sequence numbers was not clear. Minimisation and allocation were performed centrally, the clinical trials unit at the University of Aberdeen, independent of the trial researchers. Being a surgical intervention it was not possible to mask the intervention. It was not clear if the outcome assessors or the statisticians were blinded to the interventions. Parents of only one infant withdrew consent immediately after randomisation. The authors mentioned that the infant was excluded from the analysis in accordance with the UK Multicentre Research Ethics Committee (MREC) guidelines. All other infants received the allocated treatment and were followed up and accounted for at the final evaluation.All the study's prespecified outcomes were reported.

Effects of interventions

Mortality (Comparison 1):

Mortality within 28 days of the primary procedure (Outcome 1.1):

(Figure 1)

The meta-analysis did not find a statistically significant difference in mortality within 28 days of the primary procedure between the two groups (28/90 versus 30/95; typical RR 0.99, 95% CI 0.64 to 1.52; typical RD -0.00, 95% CI -0.14 to 0.13; N = 185, two trials).

Subgroup analysis

Infants less than/or equal to 1000 g: Moss 2006 did not find a statistically significant difference between the two groups (15/45 versus15/45; RR 1.0, 95% CI 0.56 to 1.79). Rees 2008 also did not find a statistically significant difference between the two groups (12/35 versus 8/33; RR 1.41, 95% CI 0.66 to 3.02). The meta-analysis combining both the studies did not find a statistically significant difference between the two groups (typical RR 1.15, 95% CI 0.72 to 1.82; typical RD 0.04, 95% CI -0.10 to 0.19; N = 158, two trials).

Infants > 1000 g: Moss 2006 did not find a statistically significant difference between the two groups (1/10 versus 7/17; RR 0.24, 95% CI 0.03 to 1.70; RD -0.31, 95% CI -0.61 to -0.01; N = 27, one trial).

Mortality within 90 days of the primary procedure (Outcome 1.2):

(Figure 2)

The meta-analysis did not find a statistically significant difference in mortality within 90 days of the primary procedure between the two groups (typical RR 1.05, 95% CI 0.71 to 1.55; typical RD 0.02, 95% CI -0.12 to 0.16; N = 185, two trials).

Subgroup analysis

Infants less than/or equal to 1000 g: Moss 2006 did not find a statistically significant difference between the two groups (16/45 versus 15/45; RR 1.07, 95% CI 0.60 to 1.89). Rees 2008 also did not find a statistically significant difference between the two groups (14/35 versus 11/33; RR 1.20, 95% CI 0.64 to 2.25). The meta-analysis combining the two studies did not find a statistically significant difference between the two groups (typical RR 1.12, 95% CI 0.74 to 1.72; typical RD 0.04, 95% CI -0.11 to 0.19; N = 158, two trials).

Infants > 1000 g: Moss 2006 did not find a statistically significant difference between the two groups (3/10 versus 7/17; RR 0.73, 95% CI 0.24 to 2.20; RD -0.11, 95% CI -0.48 to 0.26; N = 27, one trial).

Mortality within six months of the primary procedure (Outcome 1.3):

(Figure 3)

Infants less than/or equal to 1000 g: only Rees 2008 reported this outcome. They did not find a statistically significant difference between the two groups (17/35 versus 12/33; RR 1.34, 95% CI 0.76 to 2.35; RD 0.12, 95% CI -0.11 to 0.36).

Infants >1000 g: no study reported this outcome.

Mortality before discharge from the hospital (Outcome 1.4):

Infants less than/or equal to 1000 g: only Rees 2008 reported this outcome. They did not find a statistically significant difference between the two groups (17/35 versus 12/33; RR 1.34, 95% CI 0.76 to 2.35; RD 0.12, 95% CI -0.11 to 0.36).

Infants > 1000 g: no study reported this outcome.

Mortality before one year corrected age (Outcome 1.5):

(Figure 4)

Infants less than/or equal to 1000 g: only Rees 2008 reported this outcome. They did not find a statistically significant difference between the two groups (17/35 versus 12/33; RR 1.34, 95% CI 0.76 to 2.35; RD 0.12, 95% CI -0.11 to 0.36).

Infants > 1000 g: no study reported this outcome.

Need for total parenteral nutrition (TPN) (Comparison 2):

Need for TPN for more than three months after the primary procedure (Outcome 2.1):

(Figure 5)

The meta-analysis did not find a statistically significant difference between the two groups (typical RR 1.18, 95% CI 0.72 to 1.95; typical RD 0.05, 95% CI -0.11 to 0.21; N = 116, two trials).

Subgroup analysis

Infants less than/or equal to 1000 g: Moss 2006 did not find a statistically significant difference between the two groups (15/29 versus 12/30; RR 1.29, 95% CI 0.74 to 2.27). Rees 2008 also did not find a statistically significant difference between the two groups (2/18 versus 2/22; RR 1.22, 95% CI 0.19 to 7.84). The meta-analysis combining the two studies did not find a statistically significant difference between the two groups (typical RR 1.28, 95% CI 0.74 to 2.21; typical RD 0.08, 95% CI -0.09 to 0.25; N = 99, two trials).

Infants > 1000 g: Moss 2006 reported this outcome. They did not find a statistically significant difference between the two groups (2/7 versus 4/10; RR 0.71, 95% CI 0.18 to 2.88; RD -0.11, 95% CI -0.57 to 0.34).

Recurrent necrotizing enterocolitis (NEC) (Comparison 3):

Recurrent NEC after the primary procedure (Outcome 3.1):

Infants less than/or equal to 1000 g: only Rees 2008 reported this outcome. They did not find statistically significant difference between the two groups (7/33 versus 4/32; RR 1.70, 95% CI 0.55 to 5.24; RD 0.09, 95% CI -0.09 to 0.27).

Infants > 1000 g: no study reported this outcome.

Need for laparotomy (Outcome 4):

Need for laparotomy at any stage (Outcome 4.1):

(Figure 6)

The meta-analysis found a statistically significant decrease in the risk of the need for laparotomy in the peritoneal drain group (44/90 versus 95/96; typical RR 0.49, 95% CI 0.39 to 0.61; typical RD -0.51, 95% CI -0.61 to -0.41; N = 186, two trials).

Subgroup analysis

Infants less than/or equal to 1000 g: Moss 2006: found a statistically significant decrease in the risk of the need for laparotomy in the peritoneal drain group (12/45 versus 45/45; RR 0.27, 95% CI 0.17 to 0.44). Rees 2008 also found a statistically significant decrease in the risk of the need for laparotomy in the peritoneal drain group (26/35 versus 33/34; RR 0.77, 95% CI 0.62 to 0.94). The meta-analysis combining these two studies found a statistically significant decrease in the risk in the primary peritoneal drainage group (typical RR 0.48, 95% CI 0.38 to 0.61; typical RD -0.51, 95% CI -0.62 to -0.41; N = 159, two trials).

Infants > 1000 g: Moss 2006 did not find a statistically significant differences between the two groups for this outcome (6/10 versus 17/17; RR 0.61, 95% CI 0.37 to 1.00; RD -0.40, 95% CI -0.70 to 0.10).

Need for laparotomy any time after the primary procedure (Outcome 4.2):

The meta-analysis found a statistically significant increase in the risk of the need for laparotomy in the primary peritoneal drainage group (typical RR 2.65, 95% CI 1.65 to 4.26; typical RD 0.30, 95% CI 0.18 to 0.42; N = 185, two trials).

Subgroup analysis

Infants less than/or equal to 1000 g: Moss 2006: did not find a statistically significant difference between the two groups (12/45 versus 7/45; RR 1.71, 95% CI 0.74 to 3.95). Rees 2008 found that the incidence of laparotomy after the primary procedure was significantly higher in the primary peritoneal drainage group (26/35 versus 8/33; RR 3.06, 95% CI 1.63 to 5.78). The meta-analysis combining these two studies also found a statistically significant increase in the risk in the primary peritoneal drainage group (typical RR 2.44, 95% CI 1.48 to 4.03; typical RD 0.28, 95% CI 0.15 to 0.41; N = 158, two trials).

Infants > 1000 g: Moss 2006 found that the incidence of laparotomy after the primary procedure was higher in the primary peritoneal drainage group (6/10 versus 2/17; RR 5.10, 95% CI 1.26 to 20.61; RD 0.48, 95% CI 0.14 to 0.82).

Need for laparotomy within seven days after the primary procedure (Outcome 4.3):

The meta-analysis found a statistically significant increase in the risk of the need for laparotomy in the primary peritoneal drainage group (typical RR 6.37, 95% CI 1.88 to 21.54; typical RD 0.17, 95% CI 0.10 to 0.24; N = 185, two trials).

Subgroup analysis

Infants less than/or equal to 1000 g: Moss 2006 did not find a statistically significant difference between the two groups for this outcome (0/45 versus 1/45; RR 0.33, 95% CI 0.01 to 7.97). Rees 2008 found that the incidence of laparotomy within seven days after the primary procedure was significantly higher in the primary peritoneal drainage group (18/35 versus 1/33; RR 16.97, 95% CI 2.40 to 120.09). The meta-analysis found a statistically significant increase in the primary peritoneal drainage group (typical RR 7.10, 95% CI 1.94 to 25.98; typical RD 0.20, 95% CI 0.11 to 0.28; N = 158, two trials).

Infants > 1000 g: Moss 2006 did not find a statistically significant difference between the two groups for this outcome (1/10 versus 1/17; RR 1.70, 95% CI 0.12 to 24.29; RD 0.04, 95% CI -0.18 to 0.26).

Need for laparotomy after seven days following the primary procedure (Outcome 4.4):

The meta-analysis found a statistically significant increase in the risk in the primary peritoneal drainage group (typical RR 3.14, 95% CI 1.86 to 5.28; typical RD 0.32, 95% CI 0.20 to 0.44; N = 185, two trials).

Subgroup analysis

Infants less than/or equal to 1000 g: Moss 2006 did not find a statistically significant difference between the two groups for this outcome (12/45 versus 6/45; RR 2.00, 95% CI 0.82 to 4.86). Rees 2008 found a significantly higher incidence in the primary peritoneal drainage group (26/35 versus 7/33; RR 3.50, 95% CI 1.76 to 6.95). The meta-analysis combining the two studies found a statistically significant increase in the need for laparotomy in the primary peritoneal drainage group (typical RR 2.82, 95% CI 1.65 to 4.83; typical RD 0.30, 95% CI 0.18 to 0.43; N = 158, two trials).

Infants > 1000 g: Moss 2006 found a significantly higher incidence of the need for laparotomy in the primary peritoneal drainage group (5/10 versus 1/17; RR 8.50, 95% CI 1.15 to 62.80; RD 0.44, 95% CI 0.11 to 0.77).

Other complications (Comparison 5):

Abdominal abscess (Outcome 5.1):

The meta-analysis did not find a statistically significant difference between the two groups (typical RR 0.99, 95% CI 0.24 to 4.11; typical RD -0.00, 95% CI -0.06 to 0.05; N = 185, two trials).

Subgroup analysis

Infants less than/or equal to 1000 g: Moss 2006 did not find a statistically significant difference between the two groups for this outcome (0/45 versus 0/45). Rees 2008 did not find a statistically significant difference between the two groups (2/35 versus 3/33; RR 0.63, 95% CI 0.11 to 3.53). The meta-analysis combining the two studies also did not find a statistically significant difference between the two groups (typical RR 0.63, 95% CI 0.11 to 3.53; typical RD -0.01, 95% CI -0.07 to 0.04; N = 158, two trials).

Infants > 1000 g: Moss 2006 did not find a statistically significant difference between the two groups (1/10 versus 0/17; RR 4.91, 95% CI 0.22 to 110.23; RD 0.10, 95% CI -0.12 to 0.32).

Intestinal fistula after the primary procedure (Outcome 5.2):

The meta-analysis did not find a statistically significant difference between the two groups (typical RR 3.05, 95% CI 0.63 to 14.79; typical RD 0.04, 95% CI -0.01 to 0.10; N = 185, two trials).

Subgroup analysis

Infants less than/or equal to 1000 g: Moss 2006 did not find a statistically significant difference between the two groups (1/45 versus 1/45; RR 1.0, 95% CI 0.06 to 15.50). Rees 2008 did not find a statistically significant difference between the two groups (4/35 versus 1/33; RR 3.77, 95% CI 0.44 to 32.03). The meta-analysis combining the two studies also did not find a statistically significant difference between the two groups (typical RR 2.41, 95% CI 0.48 to 12.08; typical RD 0.04, 95% CI -0.03 to 0.10).

Infants > 1000 g: Moss 2006 did not find a statistically significant difference between the two groups for this outcome (1/10 versus 0/17; typical RR 4.91, 95% CI 0.22 to 110.23; typical RD 0.10, 95% CI -0.12 to 0.32).

Intestinal stricture after the primary procedure (Outcome 5.3):

The meta-analysis did not find a statistically significant difference between the two groups (typical RR 2.60, 95% CI 0.52 to 12.94; typical RD 0.03, 95% CI -0.02 to 0.09; N = 185, two trials).

Subgroup analysis

Infants less than/or equal to 1000 g: Moss 2006 did not find a statistically significant difference between the two groups for this outcome (1/45 versus 0/45; RR 3.00, 95% CI 0.13 to 71.74). Rees 2008 did not find a statistically significant difference between the two groups (2/35 versus 1/33; RR 1.89, 95% CI 0.18 to 19.83). The meta-analysis combining both studies also did not find a statistically significant difference between the two groups (typical RR 2.25, 95% CI 0.34 to 14.76; typical RD 0.02, 95% CI -0.03 to 0.08).

Infants > 1000 g: Moss 2006 did not find a statistically significant difference between the two groups (2/10 versus 1/17; RR 3.40, 95% CI 0.35 to 32.90; RD 0.14, 95% CI -0.13 to 0.41).

Urinary bladder fistula after the primary procedure (Outcome 5.4):

None of the infants in the Moss 2006 and Rees 2008 trials developed a bladder fistula.

Time to full enteral feeds (Comparison 6)

Time to full enteral feeds after the primary procedure among survivors (Outcome 6.1):

The meta-analysis including both the less than/or equal to 1000 g and > 1000 g infants could not be performed because of the lack of data in a format which could be pooled.

Infants less than/or equal to 1000 g: Moss 2006 found that time to full enteral feeds was significantly prolonged in the primary peritoneal drainage group (MD 20.77, 95% CI 3.62 to 37.92). Rees 2008 did not find a statistically significant difference between the two groups (MD -4.60, 95% CI -26.28 to 17.08). The meta-analysis combining the two studies did not find a statistically significant difference between the two groups (weighted mean difference (WMD) 11.01, 95% CI -2.44 to 24.46; N = 83, two trials).

Infants > 1000 g: Moss 2006 did not find a statistically significant difference between the two groups (MD 30.63, 95% CI -31.97 to 93.23).

Length of stay in the hospital (Comprison 7):

Length of stay in the hospital survivors (Outcome 7.1):

The meta-analysis including both the less than/or equal to 1000 g and > 1000 g infants could not be done because of the lack of data in a format which could be pooled.

Infants less than/or equal to 1000 g: Moss 2006 did not find a statistically significant difference between the two groups (MD 8.60, 95% CI -17.56 to 34.76). Rees 2008 did not find a statistically significant difference between the two groups (MD -2.71, 95% CI -41.44 to 36.02). The meta-analysis combining the two studies also did not find a statistically significant difference between the two groups (WMD 5.06, 95% CI -16.62 to 26.74; N = 87, two trials).

Infants >1000 g: Moss 2006 did not find a statistically significant difference between the two groups (MD 6.02, 95% CI -40.99 to 53.02).

Neurodevelopmental outcome at 18 to 26 months corrected age

Neither trial reported this outcome.

Cost effectiveness

Neither trial reported this outcome.

Discussion

Peritoneal drainage for perforated NEC or SIP is an attractive concept because, if effective, it will avoid exposure to inhalational anaesthesia and laparotomy in critically ill preterm infants. Clinicians and parents would be keen to adopt this approach if it can be proven that peritoneal drainage is as effective as, if not superior to, laparotomy. Hospital and National Health policy makers will also be interested if it can be proven to be a cost effective alternative to laparotomy.

This systematic review found only two trials addressing the issue of peritoneal drainage versus laparotomy. The review did not find major benefits or harms of peritoneal drainage over laparotomy as the initial surgical management. However, these results need to be interpreted with caution because the very small sample size could have easily missed clinically significant differences between the two groups.

The review also demonstrated that in the two trials, 49% (44/90) of the initially drained patients received a subsequent laparotomy; that the risk of subsequent laparotomies (both early and late) was significantly higher in the peritoneal drainage group; and that, in one trial (Moss 2006), infants less than/or equal to 1000 g in the peritoneal drainage group took a longer time to achieve full enteral feeds.

A possible explanation for the prolonged time to achieve enteral feeds in the peritoneal drainage group is the continued presence of necrotic gut and associated inflammation resulting in delayed initiation and progression of the enteral feeds. The Moss 2006 trial, which had very few crossovers from peritoneal drainage to laparotomy, showed increased time to full enteral feeds. The Rees 2008 trial protocol allowed easy provision of laparotomy, which might have resulted in minimisation of gut related morbidities and hence no differences in the time to achieve full enteral feeds. This was reflected by the fact that nearly 50% of the participants (less than/or equal to 1000 g) randomised to peritoneal drainage underwent laparotomy within one week in the Rees 2008 trial compared to none in the Moss 2006 trial.

Believers of peritoneal drainage could argue that potential for the avoidance of laparotomy and hence inhalational anaesthesia is an important benefit. On the other hand, advocates of laparotomy may argue that prolongation of time to attain full enteral feeds, by nearly 20 days, carries a significant risk of sepsis and other morbidities. Also, infants undergoing peritoneal drainage are at higher risk of having unplanned laparotomies on an emergency basis (within seven days of peritoneal drainage). Such emergency laparotomies can put infants at higher risk of intra as well as postoperative complications.

Peritoneal drainage allows the necrotic intestines to remain inside the abdomen, causing the release of inflammatory mediators which are known mediators of adverse neurodevelopmental outcomes (Grave 2007). On the other hand, use of general inhalational anaesthesia in extremely preterm infants may result in apoptosis of brain cells resulting in neurodevelopmental delay (Loepke 2008). Hence it is highly essential that the published and future RCTs report the long term neurodevelopmental outcomes of the surviving trial participants.

Two previous meta-analyses (Moss 2001: ten retrospective studies; Sola 2009: five prospective studies) found increased mortality rates for peritoneal drainage versus laparotomy. The incidence of mortality was 62.3% in the peritoneal drainage group versus 35.6% in the laparotomy group (P = 0.0009) in the Moss 2001 meta-analysis. Sola 2009 also found excessive mortality in the peritoneal drainage group (odds ratio (OR) 1.55, 95% CI 1.08 to 2.22, P = 0.02). A large prospective, multicentre observational study by the National Institute of Child Health and Human Development (NICHD) involving 156 extremely low birth weight (ELBW) infants with perforated NEC found that 48 (68%) of the infants in the initial laparotomy group had either died or developed neurodevelopmental impairment compared to 64 (84%) in the initial drain group at 18 to 22 months corrected age (Blakely 2006). However, the infants receiving peritoneal drainage were more immature and unstable than the infants who received laparotomy. The unadjusted OR for adverse outcomes in the laparotomy group relative to the drain group was substantially less than 1.0 (OR 0.39, 95% CI 0.18 to 0.86). The risk adjusted OR was also lower in the laparotomy group, but the confidence intervals were wide and hence not statistically significant (OR 0.44, 95% CI 0.16 to 1.2). After excluding all the infants who were deemed to be too sick to undergo laparotomy, and adjusting for all the confounders, the re-calculated OR continued to be lower in the laparotomy group but the results were not statistically significant (OR 0.56, 95% CI 0.19 to 1.69). Observational studies and their meta analyses suffer from limitations because of multiple inherent biases and confounding factors (Stroup 2000). Hence, their results should be interpreted cautiously and usually do not influence clinical practice.

Another issue that needs to be addressed in future RCTs is the preoperative differentiation between perforated NEC and spontaneous intestinal perforation, because SIP is usually a milder entity with better outcomes. However, experts (Blakely 2006; Rees 2008) differ on whether such differentiation is possible preoperatively. Tepas 2006 hypothesised that the acuity of the metabolic derangement is the determinant of the outcome and should dictate the choice of peritoneal drainage or laparotomy. In a retrospective study of 65 very low birth weight infants with suspected gut disruption, they investigated the effects of metabolic derangement and initial surgical care (laparotomy versus peritoneal drainage) on mortality. Metabolic derangement was scaled by assigning one point each for thrombocytopenia, metabolic acidosis, neutropenia, a left shift of segmented neutrophils, hyponatremia, bacteremia or hypotension. Multivariate logistic regression demonstrated metabolic derangement to be the best predictor of mortality (OR 4.76, 95% CI 1.41 to 16.13, P = 0.012). Infants with a metabolic derangement receiving peritoneal drainage had a four-fold increase in mortality (OR 4.43, 95% CI 1.37 to 14.29, P = 0.0126). Conversely, those without metabolic derangement and sudden free air who underwent laparotomy had a three-fold increase in mortality (OR 2.92, 95% CI 1.11 to 7.69, P = 0.03). Hence, they proposed that peritoneal drainage should be considered in infants without metabolic derangement, and laparotomy considered for those with metabolic derangement. Along similar lines, Cass 2000 and Rovin 1999 also reported positive outcomes of peritoneal drainage for infants with SIP (that is those without metabolic derangement) but not for those with NEC. Nguyen 2007 expressed a similar opinion after a review of the available literature. Since both the RCTs in our meta-analysis (Moss 2006; Rees 2008) did not stratify the intervention based on the primary diagnosis, that is SIP versus NEC, this logical hypothesis remains unanswered.

In summary, this Cochrane review found a very limited number of RCTs addressing this clinically important question, necessitating the need for further trials. Future RCTs will need to consider stratifying the infants based on the preoperative diagnosis (isolated SIP versus perforated NEC). If such differentiation is deemed difficult, the stratification could be based on objective criteria such as the presence or absence of metabolic derangement. The long term follow up of the participants from published and future RCTs is very important to find out if the type of initial surgical intervention affects neurodevelopmental outcomes. In addition, costs and cost effectiveness of peritoneal drainage over laparotomy also needs to be addressed.

Authors' conclusions

Implications for practice

No firm recommendations can be made regarding the choice of initial surgical management of perforated necrotizing enterocolitis (NEC) or spontaneous intestinal perforation (SIP) in preterm infants based on the currently available randomised controlled trials.

Implications for research

Large multicentre randomised controlled trials are needed to address this issue more definitively. Future randomised controlled trials will need to consider stratifying the infants based on the preoperative diagnosis (isolated SIP versus perforated NEC). If such differentiation is deemed difficult, the stratification could be based on objective criteria such as the presence or absence of metabolic derangement. The long term follow-up data from the published and future randomised controlled trials is essential to find out if the type of initial surgical intervention affects neurodevelopmental outcomes. In addition, costs and cost effectiveness of peritoneal drainage over laparotomy need to be addressed.

Acknowledgements

We would like to thank Prof Lawrence Moss and Clare Rees for providing additional information from their studies.

The Cochrane Neonatal Review Group has been funded in part through Federal funds from the Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health, Department of Health and Human Services, USA, under Contract No. HHSN267200603418C.

Contributions of authors

Shripada Rao (SR) performed the literature search, selected the relevant studies, assessed the methodological quality of studies, entered the data into RevMan and wrote the manuscript of the review.

Laxman Basani (LB) was mainly responsible for writing the protocol of the review. He also reviewed the draft of the review to identify any major deficiencies.

Girish Deshpande (GD) performed the literature search, selected the relevant studies, assessed the methodological quality of the studies and checked the data entered into RevMan by SR.

Naeem Samnakay (NS) contacted the authors to get additional information from their studies and checked the data entered into RevMan by SR. He also reviewed the draft of the review to identify any major deficiencies.

Karen Simmer (KS) revised and edited the draft of the protocol as well as the completed review. She was the referee reviewer at various stages of the review process.

Declarations of interest

  • None noted.

Differences between protocol and review

The title has been changed to 'Peritoneal drainage versus laparotomy as initial surgical treatment for perforated necrotizing enterocolitis or spontaneous intestinal perforation in preterm low birth weight infants'.

New outcome: need for laparotomy at any stage has been added.

New outcome: cost effectiveness has been added.

New subgroup analysis: perforated NEC versus SIP.

Potential conflict of interest

  • None noted.

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Characteristics of studies

Characteristics of Included Studies

Moss 2006

Methods

Multicentre randomised controlled trial.

Participants

Preterm infants < 34 weeks gestation with birth weight less than 1500g with evidence of intestinal perforation. The bowel perforation was defined as the presence of free intraperitoneal air on abdominal radiograph; or the presence of stool, bile or pus on abdominal paracentesis; or joint clinical opinion of the attending surgeon and the neonatologist. Infants with gastrointestinal anomalies, a previous abdominal operation, or bilateral grade 4 intraventricular haemorrhage were excluded. 117 were enrolled in the trial of which 90 were less than/or equal to1000 g and 27 were >1000g birth weight.

Interventions

55 were allocated to primary peritoneal drainage; 62 to laparotomy.

Outcomes

Dependency on total parenteral nutrition 90 days after the operation, length of hospital stay in the surviving infants.

Notes
Risk of bias table
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk

Computerised random number generator was used to generate the allocation sequence.

Allocation concealment (selection bias) Low risk

Allocation concealment was achieved by using sequentially numbered sealed envelopes.

Blinding (performance bias and detection bias) High risk

Being a surgical intervention, blinding was not possible. Statisticians were blinded to the intervention.

Incomplete outcome data (attrition bias) Low risk

There were no losses to follow up. Data for primary outcome was available on all enrolled infants.

Selective reporting (reporting bias) Low risk

All the study's prespecified outcomes were reported.

Other bias Low risk
Additional information from authors? Low risk

The authors provided clarification regarding allocation sequence generation, allocation concealment and blinding of the statisticians.

Rees 2008

Methods

Multicentre randomised controlled trial.

Participants

Preterm infants with birth weight less than/or equal to1000g with evidence of bowel perforation demonstrated as pneumoperitoneum on abdominal radiograph. 69 were enrolled in the trial.

Interventions

35 were allocated to primary peritoneal drainage and 34 to primary laparotomy.

Outcomes

Primary outcome: survival at one and six months. Secondary outcome: length of hospital stay, ventilator dependence, duration of parenteral nutrition, time to full enteral feeding.

Notes

Parents of one infant in the laparotomy group withdrew consent immediately after randomisation and hence infant was excluded from analysis by the researchers.

Risk of bias table
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk

Computerised random number generator was used to generate the allocation sequence. Patients were allocated to groups by means of weighted minimisation to ensure that the groups were balanced with respect to prognostic indicators that were likely to affect patient outcome.

Allocation concealment (selection bias) Low risk

Allocation was coordinated centrally from the clinical trial unit at the University of Aberdeen, which was entirely independent of the trial researchers.

Blinding (performance bias and detection bias) High risk

Being a surgical intervention, blinding was not possible. The statisticians were blinded to the intervention groups.

Incomplete outcome data (attrition bias) Low risk

Only one infant was withdrawn from the study postrandomisation. Data for primary outcome was available on all the remaining enrolled infants.

Selective reporting (reporting bias) Low risk

All the study's prespecified outcomes were reported.

Other bias Low risk
Additional information from authors? Low risk

The authors provided clarification regarding allocation sequence generation, allocation concealment and blinding of the statisticians.

Characteristics of excluded studies

Ahmed 1998

Reason for exclusion

Retrospective study

Azarow 1997

Reason for exclusion

Retrospective cohort study

Blakely 2005

Reason for exclusion

Prospective observational cohort study

Cheu 1988

Reason for exclusion

Retrospective study

Chiu 2006

Reason for exclusion

Retrospective case series

Demestre 2002

Reason for exclusion

Prospective observational cohort study

Dimmitt 2000

Reason for exclusion

Retrospective case series

Dzakovic 2001

Reason for exclusion

Retrospective case series

Ehrlich 2001

Reason for exclusion

Retrospective cohort study

Ibanez 2009

Reason for exclusion

Retrospective cohort study

Lessin 1998

Reason for exclusion

Retrospective case series

Morgan 1994

Reason for exclusion

Retrospective cohort study

Noble 2001

Reason for exclusion

Retrospective cohort study

Romero 2005

Reason for exclusion

Retrospective cohort study

Rovin 1999

Reason for exclusion

Retrospective cohort study

Roy 2004

Reason for exclusion

Retrospective study

Snyder 1997

Reason for exclusion

Retrospective cohort study

Takamatsu 1992

Reason for exclusion

Case series

Tepas 2006

Reason for exclusion

Retrospective cohort study

Zenciroglu 2005

Reason for exclusion

Retrospective study

Characteristics of studies awaiting classification

  • None noted.

Characteristics of ongoing studies

Blakely 2009

Study name

Laparotomy vs Drainage for Infants With Necrotizing Enterocolitis (NEST)

Methods

Multicentre randomised controlled trial

Participants

ELBW infants with necrotizing enterocolitis (NEC) or isolated intestinal perforation (IP)

Interventions

Laparotomy versus drainage as the initial surgical therapy

Outcomes

Death or neurodevelopmental impairment at 18-22 months corrected age

Starting date

January 2010

Contact information

Martin L Blakely; email: mblakely@uthsc.edu; Rosemary D Higgins; email: higginsr@mail.nih.gov

Notes

Estimated enrolment: 300

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References to studies

Included studies

Moss 2006

Published and unpublished data

Moss RL, Dimmitt RA, Barnhart DC, Sylvester KG, Brown RL, Powell DM, et al. Laparotomy versus peritoneal drainage for necrotizing enterocolitis and perforation. New England Journal of Medicine 2006;354:2225-34.

Rees 2008

Published and unpublished data

Rees CM, Eaton S, Kiely EM, Wade AM, McHugh K, Pierro A. Peritoneal drainage or laparotomy for neonatal bowel perforation? A randomized controlled trial. Annals of Surgery 2008;248:44-51.

Excluded studies

Ahmed 1998

Ahmed T, Ein S, Moore A. The role of peritoneal drains in treatment of perforated necrotizing enterocolitis: recommendations from recent experience. Journal of Pediatric Surgery 1998;33:1468-70.

Azarow 1997

Azarow KS, Ein SH, Shandling B, Wesson D, Superina R, Filler RM. Laparotomy or drain for perforated necrotizing enterocolitis: who gets what and why? Pediatric Surgery International 1997;12:137-9.

Blakely 2005

Blakely ML, Lally KP, McDonald S, Brown RL, Barnhart DC, Ricketts RR, et al; NEC Subcommittee of the NICHD Neonatal Research Network. Postoperative outcomes of extremely low birth-weight infants with necrotizing enterocolitis or isolated intestinal perforation: a prospective cohort study by the NICHD Neonatal Research Network. Annals of Surgery 2005;241:984-9.

Cheu 1988

Cheu HW, Sukarochana K, Lloyd DA. Peritoneal drainage for necrotizing enterocolitis. Journal of Pediatric Surgery 1988;23:557-61.

Chiu 2006

Chiu B, Pillai SB, Almond PS, Beth Madonna M, Reynolds M, Luck SR, Arensman RM. To drain or not to drain: a single institution experience with neonatal intestinal perforation. Journal of Perinatal Medicine 2006;34:338-41.

Demestre 2002

Demestre X, Ginovart G, Figueras-Aloy J, Porta R, Krauel X, Garcia-Alix A, Raspall F. Peritoneal drainage as primary management in necrotizing enterocolitis: a prospective study. Journal of Pediatric Surgery 2002;37:1534-9.

Dimmitt 2000

Dimmitt RA, Meier AH, Skarsgard ED, Halamek LP, Smith BM, Moss RL. Salvage laparotomy for failure of peritoneal drainage in necrotizing enterocolitis in infants with extremely low birth weight. Journal of Pediatric Surgery 2000;35:856-9.

Dzakovic 2001

Dzakovic A, Notrica DM, Smith EO, Wesson DE, Jaksic T. Primary peritoneal drainage for increasing ventilatory requirements in critically ill neonates with necrotizing enterocolitis. Journal of Pediatric Surgery 2001;36:730-2.

Ehrlich 2001

Ehrlich PF, Sato TT, Short BL, Hartman GE. Outcome of perforated necrotizing enterocolitis in the very low-birth weight neonate may be independent of the type of surgical treatment. American Surgeon 2001;67:752-6.

Ibanez 2009

Ibáñez V, Lucas J, Modesto V, Centelles I, Alberola A, Bordón F. Clinical assessment of peritoneal drainages for necrotizing enterocolitis. A Bayesian approach. Cirugia Pediatrica 2009;22:72-6.

Lessin 1998

Lessin MS, Luks FI, Wesselhoeft CW Jr, Gilchrist BF, Iannitti D, DeLuca FG. Peritoneal drainage as definitive treatment for intestinal perforation in infants with extremely low birth weight (< 750 g). Journal of Pediatric Surgery 1998;33:370-2.

Morgan 1994

Morgan LJ, Shochat SJ, Hartman GE. Peritoneal drainage as primary management of perforated NEC in the very low birth weight infant. Journal of Pediatric Surgery 1994;29:310-4.

Noble 2001

Noble HG, Driessnack M. Bedside peritoneal drainage in very low birth weight infants. American Journal of Surgery 2001;181:416-9.

Romero 2005

Romero RM, Garcia-Casillas MA, Matute JA, Barrientos G, Zamora E, Megias A, et al. Role of peritoneal drainage in very low birth weight with enterocolitis. Cirugia Pediatrica 2005;18:88-92.

Rovin 1999

Rovin JD, Rodgers BM, Burns RC, McGahren ED. The role of peritoneal drainage for intestinal perforation in infants with and without necrotizing enterocolitis. Journal of Pediatric Surgery 1999;34:143-7.

Roy 2004

Roy A, Tayeb M, Al-Khogeer S. Outcome in definite and advanced neonatal necrotizing enterocolitis. Saudi Medical Journal 2004;25:746-52.

Snyder 1997

Snyder CL, Gittes GK, Murphy JP, Sharp RJ, Ashcraft KW, Amoury RA. Survival after necrotizing enterocolitis in infants weighing less than 1, 000 g: 25 years' experience at a single institution. Journal of Pediatric Surgery 1997;32:434-7.

Takamatsu 1992

Takamatsu H, Akiyama H, Ibara S, Seki S, Kuraya K, Ikenoue T. Treatment for necrotizing enterocolitis perforation in the extremely premature infant (weighing less than 1, 000 g). Journal of Pediatric Surgery 1992;27:741-3.

Tepas 2006

Tepas JJ 3rd, Sharma R, Hudak ML, Garrison RD, Pieper P. Coming full circle: an evidence-based definition of the timing and type of surgical management of very low-birth-weight (< 1000 g) infants with signs of acute intestinal perforation. Journal of Pediatric Surgery 2006;41:418-22.

Zenciroglu 2005

Zenciroglu A, Cakmak O, Demirel N, Bas AY, Yilmaz D, Karaman I, Erdogan D. Outcome of primary peritoneal drainage for perforated necrotizing enterocolitis: comparison between laparotomy and drainage. European Journal of Pediatric Surgery 2005;15:243-47.

Studies awaiting classification

  • None noted.

Ongoing studies

Blakely 2009

[ClinicalTrials.gov: NCT01029353]

Other references

Additional references

Adzick 1992

Adzick NS, Longaker MT. Scarless fetal healing. Therapeutic implications. Annals of Surgery 1992;215:3-7.

Bell 1978

Bell MJ, Ternberg JL, Feigin RD. Neonatal necrotising enterocolitis. Therapeutic decisions based upon clinical staging. Annals of Surgery 1978;187:1-7.

Blakely 2006

Blakely ML, Tyson JE, Lally KP, McDonald S, Stoll BJ, Stevenson DK; NICHD Neonatal Research Network. Laparotomy versus peritoneal drainage for necrotizing enterocolitis or isolated intestinal perforation in extremely low birth weight infants: outcomes through 18 months adjusted age. Pediatrics 2006;117:e680-7.

Cass 2000

Cass DL, Brandt ML, Patel DL, Nuchtern JG, Minifee PK, Wesson DE. Peritoneal drainage as definitive treatment for neonates with isolated intestinal perforation. Journal of Pediatric Surgery 2000;35:1531-6.

Ein 1977

Ein SH, Marshall DG, Girvan D. Peritoneal drainage under local anesthesia for perforations from necrotizing enterocolitis. Journal of Pediatric Surgery 1977;12:963-7.

Ein 1990

Ein SH, Shandling B, Wesson D, Filler RM. A 13-year experience with peritoneal drainage under local anesthesia for necrotizing enterocolitis perforation. Journal of Pediatric Surgery 1990;25:1034-6.

Fitzgibbons 2009

Fitzgibbons SC, Ching Y, Yu D, Carpenter J, Kenny M, Weldon C, et al. Mortality of necrotizing enterocolitis expressed by birth weight categories. Journal of Pediatric Surgery 2009;44:1072-5.

Gollin 2003

Gollin G, Abarbanell A, Baerg JE. Peritoneal drainage as definitive management of intestinal perforation in extremely low-birth-weight infants. Journal of Pediatric Surgery 2003;38:1814-7.

Grave 2007

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Other published versions of this review

  • None noted.

Classification pending references

  • None noted.

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Data and analyses

1 Mortality

For graphical representations of the data/results in this table, please use link under "Outcome or Subgroup".

Outcome or Subgroup Studies Participants Statistical Method Effect Estimate
1.1 Mortality within 28 days of the primary procedure 2 Risk Ratio (M-H, Fixed, 95% CI) Subtotals only
1.1.1 All infants 2 185 Risk Ratio (M-H, Fixed, 95% CI) 0.99 [0.64, 1.52]
1.1.2 Less than 1000g 2 158 Risk Ratio (M-H, Fixed, 95% CI) 1.15 [0.72, 1.82]
1.1.3 More than 1000g 1 27 Risk Ratio (M-H, Fixed, 95% CI) 0.24 [0.03, 1.70]
1.2 Mortality within 90 days of the primary procedure 2 Risk Ratio (M-H, Fixed, 95% CI) Subtotals only
1.2.1 All infants 2 185 Risk Ratio (M-H, Fixed, 95% CI) 1.05 [0.71, 1.55]
1.2.2 Less than 1000g 2 158 Risk Ratio (M-H, Fixed, 95% CI) 1.12 [0.74, 1.72]
1.2.3 More than 1000g 1 27 Risk Ratio (M-H, Fixed, 95% CI) 0.73 [0.24, 2.20]
1.3 Mortality within 6 months of primary procedure 1 68 Risk Ratio (M-H, Fixed, 95% CI) 1.34 [0.76, 2.35]
1.3.1 less than/or equal to 1000g 1 68 Risk Ratio (M-H, Fixed, 95% CI) 1.34 [0.76, 2.35]
1.4 Mortality before discharge from hospital 1 68 Risk Ratio (M-H, Fixed, 95% CI) 1.34 [0.76, 2.35]
1.4.1 Less than 1000g 1 68 Risk Ratio (M-H, Fixed, 95% CI) 1.34 [0.76, 2.35]
1.5 Mortality before corrected age of one year 1 68 Risk Ratio (M-H, Fixed, 95% CI) 1.34 [0.76, 2.35]
1.5.1 Less than 1000g 1 68 Risk Ratio (M-H, Fixed, 95% CI) 1.34 [0.76, 2.35]

2 Need for total parenteral nutrition (TPN)

For graphical representations of the data/results in this table, please use link under "Outcome or Subgroup".

Outcome or Subgroup Studies Participants Statistical Method Effect Estimate
2.1 Need for TPN for more than 3 months after the primary procedure among survivors 2 Risk Ratio (M-H, Fixed, 95% CI) Subtotals only
2.1.1 All infants 2 116 Risk Ratio (M-H, Fixed, 95% CI) 1.18 [0.72, 1.95]
2.1.2 Less than 1000g 2 99 Risk Ratio (M-H, Fixed, 95% CI) 1.28 [0.74, 2.21]
2.1.3 More than 1000g 1 17 Risk Ratio (M-H, Fixed, 95% CI) 0.71 [0.18, 2.88]

3 Recurrent necrotizing enterocolitis (NEC)

For graphical representations of the data/results in this table, please use link under "Outcome or Subgroup".

Outcome or Subgroup Studies Participants Statistical Method Effect Estimate
3.1 Recurrent NEC after primary procedure 1 65 Risk Ratio (M-H, Fixed, 95% CI) 1.70 [0.55, 5.24]
3.1.1 Less than 1000g 1 65 Risk Ratio (M-H, Fixed, 95% CI) 1.70 [0.55, 5.24]

4 Need for laparotomy

For graphical representations of the data/results in this table, please use link under "Outcome or Subgroup".

Outcome or Subgroup Studies Participants Statistical Method Effect Estimate
4.1 Need for laparotomy at any stage 2 Risk Ratio (M-H, Fixed, 95% CI) Subtotals only
4.1.1 All infants 2 186 Risk Ratio (M-H, Fixed, 95% CI) 0.49 [0.39, 0.61]
4.1.2 less than/or equal to 1000 gram 2 159 Risk Ratio (M-H, Fixed, 95% CI) 0.48 [0.38, 0.61]
4.1.3 >1000 grams 1 27 Risk Ratio (M-H, Fixed, 95% CI) 0.61 [0.37, 1.00]
4.2 Need for laparotomy any time after the primary procedure 2 Risk Ratio (M-H, Fixed, 95% CI) Subtotals only
4.2.1 All infants 2 185 Risk Ratio (M-H, Fixed, 95% CI) 2.65 [1.65, 4.26]
4.2.2 Less than 1000g 2 158 Risk Ratio (M-H, Fixed, 95% CI) 2.44 [1.48, 4.03]
4.2.3 More than 1000g 1 27 Risk Ratio (M-H, Fixed, 95% CI) 5.10 [1.26, 20.61]
4.3 Need for laparotomy within 7 days of the primary procedure 2 Risk Ratio (M-H, Fixed, 95% CI) Subtotals only
4.3.1 All infants 2 185 Risk Ratio (M-H, Fixed, 95% CI) 6.37 [1.88, 21.54]
4.3.2 Less than 1000g 2 158 Risk Ratio (M-H, Fixed, 95% CI) 7.10 [1.94, 25.98]
4.3.3 More than 1000g 1 27 Risk Ratio (M-H, Fixed, 95% CI) 1.70 [0.12, 24.29]
4.4 Need for laparotomy after 7 days of the primary procedure 2 Risk Ratio (M-H, Fixed, 95% CI) Subtotals only
4.4.1 All infants 2 185 Risk Ratio (M-H, Fixed, 95% CI) 3.14 [1.86, 5.28]
4.4.2 Less than 1000g 2 158 Risk Ratio (M-H, Fixed, 95% CI) 2.82 [1.65, 4.83]
4.4.3 More than 1000g 1 27 Risk Ratio (M-H, Fixed, 95% CI) 8.50 [1.15, 62.80]

5 Other complications

For graphical representations of the data/results in this table, please use link under "Outcome or Subgroup".

Outcome or Subgroup Studies Participants Statistical Method Effect Estimate
5.1 Abdominal abscess 2 Risk Ratio (M-H, Fixed, 95% CI) Subtotals only
5.1.1 All infants 2 185 Risk Ratio (M-H, Fixed, 95% CI) 0.99 [0.24, 4.11]
5.1.2 Less than 1000g 2 158 Risk Ratio (M-H, Fixed, 95% CI) 0.63 [0.11, 3.53]
5.1.3 More than 1000g 1 27 Risk Ratio (M-H, Fixed, 95% CI) 4.91 [0.22, 110.23]
5.2 Intestinal fistula after the primary procedure 2 Risk Ratio (M-H, Fixed, 95% CI) Subtotals only
5.2.1 All infants 2 185 Risk Ratio (M-H, Fixed, 95% CI) 3.05 [0.63, 14.79]
5.2.2 Less than 1000g 2 158 Risk Ratio (M-H, Fixed, 95% CI) 2.41 [0.48, 12.08]
5.2.3 More than 1000g 1 27 Risk Ratio (M-H, Fixed, 95% CI) 4.91 [0.22, 110.23]
5.3 Intestinal stricture after the primary procedure 2 Risk Ratio (M-H, Fixed, 95% CI) Subtotals only
5.3.1 All infants 2 185 Risk Ratio (M-H, Fixed, 95% CI) 2.60 [0.52, 12.94]
5.3.2 Less than 1000g 2 158 Risk Ratio (M-H, Fixed, 95% CI) 2.25 [0.34, 14.76]
5.3.3 More than 1000g 1 27 Risk Ratio (M-H, Fixed, 95% CI) 3.40 [0.35, 32.90]
5.4 Bladder fistula 2 370 Risk Ratio (M-H, Fixed, 95% CI) Not estimable
5.4.1 All infants 2 185 Risk Ratio (M-H, Fixed, 95% CI) Not estimable
5.4.2 Less than 1000g 2 158 Risk Ratio (M-H, Fixed, 95% CI) Not estimable
5.4.3 More than 1000g 1 27 Risk Ratio (M-H, Fixed, 95% CI) Not estimable

6 Time to full enteral feeds

For graphical representations of the data/results in this table, please use link under "Outcome or Subgroup".

Outcome or Subgroup Studies Participants Statistical Method Effect Estimate
6.1 Time to full enteral feeds among survivors 2 Mean Difference (IV, Fixed, 95% CI) Subtotals only
6.1.1 Less than 1000g 2 83 Mean Difference (IV, Fixed, 95% CI) 11.01 [-2.44, 24.46]
6.1.2 More than 1000g 1 10 Mean Difference (IV, Fixed, 95% CI) 30.63 [-31.97, 93.23]

7 Length of stay in the hospital

For graphical representations of the data/results in this table, please use link under "Outcome or Subgroup".

Outcome or Subgroup Studies Participants Statistical Method Effect Estimate
7.1 Length of stay in the hospital among survivors to discharge 2 Mean Difference (IV, Fixed, 95% CI) Subtotals only
7.1.1 Less than 1000g 2 87 Mean Difference (IV, Fixed, 95% CI) 5.06 [-16.62, 26.74]
7.1.2 More than 1000g 1 15 Mean Difference (IV, Fixed, 95% CI) 6.02 [-40.99, 53.02]

8 Length of stay in the hospital

For graphical representations of the data/results in this table, please use link under "Outcome or Subgroup".

Outcome or Subgroup Studies Participants Statistical Method Effect Estimate
8.1 Length of stay in the hospital among survivors to discharge 2 Mean Difference (IV, Fixed, 95% CI) Subtotals only
8.1.1 Less than 1000g 2 87 Mean Difference (IV, Fixed, 95% CI) 5.06 [-16.62, 26.74]
8.1.2 More than 1000g 1 15 Mean Difference (IV, Fixed, 95% CI) 6.02 [-40.99, 53.02]

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Figures

Figure 1 (Analysis 1.1)

Refer to figure 1 caption below.

Forest plot of comparison: 1 Mortality, outcome: 1.1 Mortality within 28 days of the primary procedure (Figure 1 summary).

Figure 2 (Analysis 1.2)

Refer to figure 2 caption below.

Forest plot of comparison: 1 Mortality, outcome: 1.2 Mortality within 90 days of the primary procedure (Figure 2 summary).

Figure 3 (Analysis 1.3)

Refer to figure 3 caption below.

Forest plot of comparison: 1 Mortality, outcome: 1.3 Mortality within 6 months of primary procedure (Figure 3 summary).

Figure 4 (Analysis 1.5)

Refer to figure 4 caption below.

Forest plot of comparison: 1 Mortality, outcome: 1.5 Mortality before corrected age of one year (Figure 4 summary).

Figure 5 (Analysis 2.1)

Refer to figure 5 caption below.

Forest plot of comparison: 2 Need for TPN, outcome: 2.1 Need for TPN for more than 3 months after the primary procedure among survivors (Figure 5 summary).

Figure 6 (Analysis 4.1)

Refer to figure 6 caption below.

Forest plot of comparison: 4 Need for laparotomy, outcome: 4.1 Need for laparotomy at any stage (Figure 6 summary).

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Sources of support

Internal sources

  • King Edward Memorial Hospital for Women, Perth, Australia
  • Princess Margaret Hospital for Children, Perth, Australia
  • Royal North Shore Hospital, Sydney, Australia

External sources

  • No sources of support provided.

This review is published as a Cochrane review in The Cochrane Library, Issue 6, 2011 (see http://www.thecochranelibrary.com External Web Site Policy for information). Cochrane reviews are regularly updated as new evidence emerges and in response to feedback. The Cochrane Library should be consulted for the most recent version of the review.