Laparoscopic entry techniques: Cochrane systematic review

Abstract

Assessed as up to date: 2014/09/01

Background

Laparoscopy is a common procedure in many surgical specialities. Complications arising from laparoscopy are often related to initial entry into the abdomen. Life-threatening complications include injury to viscera e.g. the bowel or bladder, or to vasculature e.g. major abdominal and anterior abdominal wall vessels. Minor complications can also occur, such as postoperative wound infection, subcutaneous emphysema, and extraperitoneal insufflation. There is no clear consensus as to the optimal method of laparoscopic entry into the peritoneal cavity.

Objectives

To evaluate the benefits and risks of different laparoscopic entry techniques in gynaecological and non-gynaecological surgery.

Search methods

This updated review has drawn on the search strategy developed by the Cochrane Menstrual Disorders and Subfertility Group. In addition, MEDLINE, EMBASE, CENTRAL and PsycINFO were searched through to September 2014.

Selection criteria

We included randomised controlled trials (RCTs) in which one laparoscopic entry technique was compared with another.

Data collection and analysis

Two authors independently selected studies, assessed risk of bias, and extracted data. We expressed findings as Peto odds ratios (Peto ORs) with 95% confidence intervals (CIs). We assessed statistical heterogeneity using the I² statistic. We assessed the overall quality of evidence for the main comparisons using GRADE methods.

Main results

The review included 46 RCTs including three multi-arm trials (7389 participants) and evaluated 13 laparoscopic entry techniques. Overall there was no evidence of advantage using any single technique for preventing major vascular or visceral complications. The evidence was generally of very low quality; the main limitations were imprecision and poor reporting of study methods.

Open-entry versus closed-entry There was no evidence of a difference between the groups for vascular (Peto OR 0.14, 95% CI 0.00 to 6.82, three RCTs, n = 795, I2 = n/a; very low quality evidence) or visceral injury (Peto OR 0.61, 95% CI 0.06 to 6.08, three RCTs, n = 795, I2 = 0%; very low quality evidence). There was a lower risk of failed entry in the open-entry group (Peto OR 0.16, 95% CI 0.04 to 0.63, n = 665, two RCTs, I2 = 0%; very low quality evidence). This suggests that for every 1000 patients operated on, 31 patients in the closed-entry group will have failed entry compared to between 1 to 20 patients in the open-entry group. No events were reported in any of the studies for mortality, gas embolism or solid organ injury.

Direct trocar versus Veress needle entry There was a lower risk of vascular injury in the direct trocar group (Peto OR 0.13, 95% CI 0.03 to 0.66, five RCTs, n = 1522, I2 = 0%; low quality evidence) and failed entry (Peto OR 0.21, 95% CI 0.14 to 0.30, seven RCTs, n = 3104; I ²= 0%; moderate quality evidence). This suggests that for every 1000 patients operated on, 8 patients in the Veress needle group will experience vascular injury compared to between 0 to 5 patients in the direct trocar group; and that 64 patients in the Veress needle group will experience failed entry compared to between 10 to 20 patients in the direct trocar group. The vascular injury significance is sensitive to choice of statistical analysis and may be unreliable. There was no evidence of a difference between the groups for visceral (Peto OR 1.02, 95% CI 0.06 to 16.24, four RCTs, n = 1438, I2 = 49%; very low quality evidence) or solid organ injury (Peto OR 0.16, 95% Cl 0.01 to 2.53, two RCTs, n = 998, I2 = n/a; very low quality evidence). No events were recorded for mortality or gas embolism.

Direct vision entry versus Veress needle entry There was no evidence of a difference between the groups in the rates of visceral injury (Peto OR 0.15, 95% CI 0.01 to 2.34, one RCT, n = 194; very low quality evidence). Other primary outcomes were not reported.

Direct vision entry versus open-entry There was no evidence of a difference between the groups in the rates of visceral injury (Peto OR 0.13, 95% CI 0.00 to 6.50, two RCTs, n = 392; low quality evidence), solid organ injury (Peto OR 6.16, 95% CI 0.12 to 316.67, one RCT, n = 60, I2 = n/a; very low quality evidence), or failed entry (Peto OR 0.40, 95% CI 0.04 to 4.09, one RCT, n = 60; low quality evidence). Vascular injury was reported, however no events occurred. Our other primary outcomes were not reported.

Radially expanding (STEP) trocars versus non-expanding trocars There was no evidence of a difference between the groups for vascular injury (Peto OR 0.24, 95% Cl 0.05 to 1.21, two RCTs, n = 331, I2 = 0%; low quality evidence), visceral injury (Peto OR 0.13, 95% CI 0.00 to 6.37, two RCTs, n = 331, I2 = n/a; low quality evidence), or solid organ injury (Peto OR 1.05, 95% CI 0.07 to 16.91, one RCT, n = 244; very low quality evidence). Other primary outcomes were not reported.

Comparisons of other laparoscopic entry techniques

There was a higher risk of failed entry in the group in which the abdominal wall was lifted before Veress needle insertion than in the not-lifted group (Peto OR 4.44, 95% CI 2.16 to 9.13, one RCT, n = 150; very low quality evidence). There was no evidence of a difference between the groups in rates of visceral injury or extraperitoneal insufflation. The studies had small numbers and excluded many patients with previous abdominal surgery, and women with a raised body mass index. These patients may have unusually high complication rates.

Authors' conclusions

Overall, there is insufficient evidence to recommend one laparoscopic entry technique over another.

An open-entry technique is associated with a reduction in failed entry when compared to a closed-entry technique, with no evidence of a difference in the incidence of visceral or vascular injury.

An advantage of direct trocar entry over Veress needle entry was noted for failed entry and vascular injury. The evidence was generally of very low quality with small numbers of participants in most studies; our findings should be interpreted with caution.

Author(s)

Ahmad Gaity, Gent David, Henderson Daniel, O'Flynn Helena, Phillips Kevin, Watson Andrew

Summary

Laparoscopic entry techniques

Review question

Cochrane review authors evaluated the benefits and risks of different laparoscopic entry techniques in gynaecological and non-gynaecological surgery.

Background

Laparoscopy is a procedure which uses a laparoscope, a thin tube with a light and camera on the end, like a telescope, that is inserted under general anaesthesia through a small cut (0.5 cm to 1 cm) in, or near, the umbilicus. The camera can project images onto external screens which allow surgeons to directly visualise the pelvic and abdominal organs. This permits keyhole surgery to be performed, which uses much smaller surgical tools without the need for large incisions. To perform laparoscopy, gas is gently pumped into the abdomen to increase the workspace for the camera and tools. The method by which incisions are made to introduce the laparoscope may influence the likelihood of complications.

Although laparoscopy is usually safe, a small minority of patients experience life-threatening complications, including injuries to surrounding blood vessels or the bowel. These complications often occur at the first step of the procedure when the abdominal wall is pierced using specialised instruments to insert the gas. Different doctors use different specialised instruments and techniques.

Study characteristics

Forty-six randomised controlled trials with a total of 7389 individuals undergoing laparoscopy were included in the systematic review. The RCTs compared 13 different laparoscopic entry techniques. The patients included in the review were men, women, and children requiring laparoscopic surgery for a range of gynaecological and non-gynaecological conditions. The duration of the included studies ranged from 5 months to 5 years. Sources of funding were not mentioned in 43 out of 46 studies. Three studies received funding from industry through either a grant or free use of medical equipment during their trials. The evidence is current to September 2014.

Key results

There was a reduction in the rate of failed entry with the use of an open-entry technique in comparison to a closed-entry technique (three RCTs, 665 participants, very low quality evidence). The evidence suggests that for every 1000 patients operated on, 31 patients in the closed-entry group will have failed entry compared to between 1 to 20 patients in the open-entry group.

Comparing closed techniques, a reduction in the risk of vascular injury (five RCTs, 1522 participants, low quality evidence) and a reduction in failed entry (seven RCTs, 3104 participants, moderate quality evidence) were demonstrated with the use of a direct trocar entry technique in comparison to Veress needle entry. Here the evidence suggests that for every 1000 patients operated on, eight patients in the Veress needle group will experience vascular injury compared to between 0 to 5 patients in the direct trocar group; and 64 patients in the Veress needle group will experience failed entry compared to between 10 to 20 patients in the Direct trocar group. The vascular injury risk depends on how the data are analysed and may be unreliable.

SILS (single incision laparoscopic surgery) was not shown to reduce major complication rates, but was shown to prolong operation times and possibly result in less bleeding at the incision sites.

Overall, there is insufficient evidence to recommend one laparoscopic entry technique over another. More research is required regarding safety of entry techniques and to discover if the risk of major complications differ between the techniques.

Quality of the evidence

The GRADE scores for the majority of studies were low or very low. Limitations included imprecision and poor reporting of study methods.

Reviewer's Conclusions

Implications for practice

The open-entry technique is associated with a reduction in failed entry when compared to the closed-entry technique, with no evidence of a difference in the incidence of visceral or vascular injury.

Benefits were noted with the use of the direct trocar entry technique when compared to Veress needle entry. The use of the Veress needle was associated with an increased incidence of failed entry.

Not lifting the abdominal wall before Veress needle insertion was associated with a reduction in failed entry compared to lifting the abdominal wall before Veress needle insertion. This was the only other comparison that demonstrated evidence of a difference for one of our primary outcomes.

The low rate of reported complications associated with laparoscopic entry and the small number of participants within the included studies may account for the lack of significant difference in terms of major vascular and visceral injury between most entry techniques. Results should be interpreted with caution for outcomes where only single studies were included.

Implications for research

Randomised controlled trials (RCTs) of adequate power are required to detect a significant reduction in risks of major complications. In order to increase cohort size enough to gain the statistical power needed to be able to detect rare major complications, the number of patients required would need to be in the hundreds of thousands and it is unlikely that these studies could be performed. This dilemma has been explored recently by Cuss 2014 who suggest that the evidence for laparoscopic surgery may be at the limit of what is possible. In order to address this issue, we suggest that a centralised national register could be created. Although this would not produce RCT-level evidence, it would enable collation of all information on laparoscopic complications and thus provide cohort sizes large enough to reliably identify major complications. This could be modelled on the existing maternal mortality databases. The onus would be on individual surgeons to be transparent in their reporting of complications.

Further well designed RCTs of sufficient power are required to determine the optimal entry technique in patients with extreme BMI and those with previous abdominal and pelvic surgery.

Future meta-analyses ought to consider using individual patient data (IPD) analysis. Aggregate data meta-analysis means accepting the reporting methods of each individual study and using their outcomes for analysis. Therefore any selective bias, publication bias or flaws in reporting protocol will influence the meta-analysis outcome. Although much more resource intensive, as all raw data from individual studies must be obtained and reanalysed using advanced statistical methods, IPD analysis would allow all data analysis to be standardised and reported consistently.

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