Laparoscopic Entry Techniques
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To compare different laparoscopic entry techniques.
Background
Laparoscopic surgery is a surgical technique in which operations in the abdomen and pelvis are performed through small incisions (0.5cm to 1.5cm) using a laparoscope (medical telescope that is usually inserted under general anaesthetic through or near the umbilicus). This is a very common procedure in gynaecology and increasingly used in other specialities. Initially and still commonly it was used to inspect the pelvis in order to make a diagnosis (for instance ectopic pregnancy or endometriosis). It is now increasing used to enable minimal access surgery (e.g. ovarian cystectomy or salpingectomy for ectopic pregnancy). There is evidence that laparoscopic surgery provides significant benefits compared with laparotomy, for patients and health care providers. The benefits for patients include less visible scarring, less post operative pain and quicker recovery. The benefits for health care providers include shorter hospital stay and thus reduced inpatient costs. The benefits for surgeons include no touch operative technique.
Although the number of laparoscopic surgical complications is significantly less when compared with laparotomy, they still occur. Most of these complications are related to the laparoscopic method of entry (Jansen, 2004). The most important complications can be life threatening and include bowel, major abdominal vessels and anterior abdominal wall vessel perforation. Fortunately, these most serious complications are rare, with the incidence of bowel perforation reported as being 1.8 per 1000 cases, and the incidence of major abdominal vessels and anterior abdominal wall vessel perforation reported as being 0.9 per 1000 cases (RCOG, 1978). Whilst these low rates are heartening, it still implies over 250 individuals in the United Kingdom will suffer a serious complication each year (BSGE, 1999). As well as these very serious operative complications, there are other less serious complications such as post operative infecton, subcutaneous emphysema and extraperitoneal insufflation (Copeland, 1983; Sigman, 1993).
Many differing laparoscopic entry methods have been described. These include a closed technique which has two variations. The first involves the insertion of a Veress needle into the peritoneal cavity, followed by gas insufflation (act of blowing) then insertion of a trocar (a sharp pointed instrument with a cannula used to enter body cavity) and then the laparoscope. The second involves the insertion of a trocar directly into the peritoneal cavity followed by laparoscopic inspection and then gas insufflation. The potential benefits of the closed technique are suggested to be shorter operating times, immediate recognition of bowel or vascular injuries and near exclusion of entry failure (Copeland 1983). The alternative open technique involves the peritoneal being cut‐down first followed by the insertion of a blunt trocar under direct visualisation, gas insufflation and then insertion of the laparoscope. The potential benefits of this technique are suggested to be the prevention of bowel injury, gas embolism, pre‐peritoneal insufflation and a low incidence of vascular injury (Sigman, 1993). However, direct entry may be an under‐utilised and safe alternative to the Veress needle and open entry technique (Molloy, 2002). Several other methods, such as the use of optical trocars, radically dilating trocars and threaded trocars have also been described.
There is no clear consensus as to the optimal method of entry into the peritoneal cavity (Molloy, 2002; Merlin, 2003). A consensus meeting regarding laparoscopic entry technique was held in 1999 and the resultant document is felt to represent best practice by many (BSGE, 1999). However many laparoscopic surgeons do not follow this Middlesbrough Consensus ( Lalchandani, 2005; Ahmad, 2007) The document emphasised the need for an intraumblical incision, sharp Veress needle, flat position of the patient and pressure not volume of gas to determine when to place the trocar in the peritoneal cavity. There is also a recommendation that all entry phases of laparoscopy should be performed with the patient lying level with no Trendelenburg tilt, because this patient position rotates the sacral promontory and brings the aortic bifurcation close to the umbilicus and thusincreases chances of vascular injury (Pasic, 1998). It also states that intra‐abdominal pressure should be used as a guide rather than volume of infused carbon dioxide to determine when to site the primary trocar. Garry et al (Garry, 1997)) measured the distance between the abdominal wall and underlying bowel at different intra‐abdominal pressures. They reported that at an intra‐abdominal pressure of 25 mmHg the distance would be 10 cm. They also noted that even with difficult trocar insertion, which could require a force of up to 4 to 5 kg, at an intra abdominal pressure of 25 mmHg, there would still be a safety distance of 5 cm between abdominal wall and underlying structures. This high intra abdominal pressure should in theory minimise the risk of visceral and vascular injury.
This meta‐analysis aims to compare the different laparoscopic entry methods in terms of their influence on post‐operative complications.
Objectives
To compare different laparoscopic entry techniques.
Methods
Criteria for considering studies for this review
Types of studies
Randomised controlled trials will be included where one laparoscopic entry technique is being compared with another.
Types of participants
Patients undergoing diagnostic operative or mixed laparoscopic surgery, preformed either by gynaecologists or general surgeons.
Types of interventions
The following laparoscopic entry techniques will be analysed.
1. Open entry technique versus closed entry technique.
a. Open entry technique versus verres needle entry technique.
b. Open entry technique versus direct trocar entry.
2. Verres needle insertion versus direct trocar insertion.
3. Direct vision entry versus verres needle entry.
4. Disposable instruments versus reusable instruments.
5. Radially expanding trocars versus standard trocars.
6. Trendelenberg position for entry versus supine poison for entry.
7. Volume of gas used as an indictor for entry versus intraabdominal pressure as an indicator for entry.
8. Site of entry.
9. Any other laparoscopic entry technique comparing any other laparoscopic entry technique.
Types of outcome measures
Primary o utcome m easure
1. Major complications
a. Mortality
b. Vascular injury
c. Visceral (bladder or bowel) injury
d. Gas embolism
Secondary outcome measure s
1. Any minor complication
2. Failed entry (unable to access the peritoneal cavity)
Search methods for identification of studies
We will search the following databases.
1. The Menstrual Disorders & Subfertility Group's Specialised Register of controlled trials for any trials with keywords in the title, abstract or keyword sections.
2. Using Ovid software: MEDLINE (from 1966 to December, 2006) and EMBASE (from 1980 to December, 2006).
EMBASE using the following terms combined with the methodological filters:
1.controlled study/ or randomized controlled trial/ (2276212)
2.double blind procedure/ (61537)
3.single blind procedure/ (6140)
4.Crossover Procedure/ (17930)
5.drug comparison/ (81250)
6.placebo/ (90992)
7.random$.tw. (317764)
8.latin square.tw. (1027)
9.crossover.tw. (23314)
10.cross‐over.tw. (10999)
11.placebo$.tw. (94492)
12.((doubl$ or singl$ or tripl$ or trebl$) adj5 (blind$ or mask$)).tw. (82682)
13.(comparativ$ adj5 trial$).tw. (4312)
14.(clinical adj5 trial$).tw. (98308)
15.animal/ not (human/ and animal/) (12834)
16.or/1‐14 (2592396)
17.16 not 15 (2591118)
18.laparoscopy/ (16106)
19.laparoscop$.ti,ab,hw,tn,mf. (42950)
20.pelvic endoscop$.ti,ab,hw,tn,mf. (8)
21.peritoneoscop$.ti,ab,hw,tn,mf. (259)
22.videolaparoscop$.ti,ab,hw,tn,mf. (175)
23.entry technique$.ti,ab,hw,tn,mf. (51)
24.Veress needl$.ti,ab,hw,tn,mf. (209)
25.trocar$.ti,ab,hw,tn,mf. (2310)
26.trocar/ (634)
27.open entr$.ti,ab,hw,tn,mf. (15)
28.closed entr$.ti,ab,hw,tn,mf. (9)
29.pneumoperiton$.ti,ab,hw,tn,mf. (3146)
30.body position/ or body posture/ or supine position/ (21653)
31.supine position$.ti,ab,hw,tn,mf. (7169)
32.lithotomy/ (526)
33.lithotomy.ti,ab,hw,tn,mf. (778)
34.patient$ position$.ti,ab,hw,tn,mf. (6713)
35.French position$.ti,ab,hw,tn,mf. (7)
36.American position$.ti,ab,hw,tn,mf. (5)
37.(side adj position$).ti,ab,hw,tn,mf. (85)
38.(side adj approach$).ti,ab,hw,tn,mf. (30)
39.Postoperative Complication/ (83037)
40.neuropraxia.ti,ab,hw,tn,mf. (136)
41.complication$.ti,ab,hw,tn,mf. (357071)
42.or/18‐22 (43027)
43.or/23‐38 (35478)
44.or/39‐41 (357141)
45.42 and 43 (3693)
46.17 and 45 (1107)
47.44 and 46 (371)
48.from 47 keep 1‐371 (371)
MEDLINE using the following terms combined with the methodological filters:
1.randomized controlled trial.pt. (244089)
2.controlled clinical trial.pt. (78416)
3.Randomized Controlled Trials/ (50797)
4.Random allocation/ (60333)
5.double‐blind method/ (93917)
6.single‐blind method/ (11204)
7.or/1‐6 (413999)
8.clinical trial.pt. (470405)
9.exp clinical trials/ (201963)
10.(clin$ adj25 trial$).ti,ab,sh. (135368)
11.((singl$ or doubl$ or tripl$ or trebl$) adj25 (blind$ or mask$)).ti,ab,sh. (92589)
12.Placebos/ (26655)
13.placebo$.ti,ab,sh. (117392)
14.random$.ti,ab,sh. (508048)
15.Research design/ (47651)
16.or/8‐15 (904759)
17.animal/ not (human/ and animal/) (3152830)
18.7 or 16 (911400)
19.18 not 17 (837794)
20.laparoscopy/ (33999)
21.laparoscop$.ti,ab,sh. (49539)
22.pelvic endoscop$.ti,ab,sh. (17)
23.peritoneoscop$.ti,ab,sh. (448)
24.videolaparoscop$.ti,ab,sh. (213)
25.entry technique$.ti,ab,sh. (46)
26.Veress needl$.ti,ab,sh. (221)
27.trocar$.ti,ab,sh. (2641)
28.open entr$.ti,ab,sh. (19)
29.closed entr$.ti,ab,sh. (9)
30.pneumoperiton$.ti,ab,sh. (4864)
31.posture/ or supine position/ (46426)
32.supine position$.ti,ab,sh. (7599)
33.lithotomy.ti,ab,sh. (609)
34.patient$ position$.ti,ab,sh. (1662)
35.French position$.ti,ab,sh. (7)
36.American position$.ti,ab,sh. (6)
37.(side adj position$).ti,ab,sh. (109)
38.(side adj approach$).ti,ab,sh. (54)
39.exp Postoperative Complications/ (305483)
40.neuropraxia.ti,ab,sh. (169)
41.complication$.ti,ab,sh. (360039)
42.or/20‐24 (49708)
43.or/25‐38 (58004)
44.or/39‐41 (595720)
45.and/42‐44 (1839)
46.19 and 45 (258)
47.from 46 keep 1‐258 (258)
Data collection and analysis
Study selection
GA and JD will independently select the trials to be included in accordance with the aforementioned criteria. AW will resolve any disagreements.
Data extraction
Two review authors (GA and JD) will independently extract data using forms designed according to Cochrane guidelines. All discrepancies will be resolved by AW. This information will be presented in the table 'Characteristics of included studies'. Additional information, on trial methodology or original trial data or both, will be sought from the authors of trials which appears to meet the eligibility criteria but had aspects of methodology that were unclear, or if the data was in a form unsuitable for meta‐analysis.
Quality assessment
Two review authors (GA and JD) will independently assess the quality of included studies for the following quality criteria and methodological details. This will help provide a context for discussing the reliability of results.
1. Method of randomisation:
a. truly randomised: centralised randomisation scheme (telephone or pharmacy) or on‐site computer system;
b. not stated.
2. Presence or absence of blinding to treatment allocation.
3. Quality of allocation concealment. Allocation concealment will be scored according to the categories used by the Cochrane Collaboration:
a. allocation concealment was adequate;
b. unclear;
c. inadequate or not used.
4. Number of women recruited, randomised, excluded, analysed or lost to follow up.
5. Surgeons:
a. same surgeon;
b. group of surgeons performing procedure in each arm of trial.
6. Duration of follow up:
a. outcome data used for primary analysis complete ‐ all randomised patients are accounted for, with 'intention to treat' analysis;
b. completeness of data uncertain;
c. outcome data incomplete.
7. Co‐intervention:
a. other than for use of intervention under study protocols were equivalent in treatment and control groups;
b. issue of co‐intervention not considered;
c. co‐intervention definitely exists.
8. Location of trial:
a. single centre;
b. multi‐centre.
9. Whether a power calculation was done.
Data analysis
We will perform statistical analysis in accordance with the guidelines for statistical analysis as per the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2005). Heterogeneity between results of the different studies will be examined by inspecting the scatter in the data points and the overlap in their confidence intervals and, more formally by checking the chi‐squared statistics. If possible, the outcomes will be pooled statistically.
The influence of confounding variables will be assessed during critical appraisal of each study. These confounders may include previous abdominal surgery, patient weight, patient position, access site, surgical skill, age and sex.
All the primary outcome measures for this review use binary data. Results for each study will be expressed as an odds ratio with 95% confidence intervals and combined for meta‐analysis with RevMan software using fixed‐effect methods. In case of statistical heterogeneity, a random‐effects model will be adopted. Sensitivity analysis will be carried out if there are sufficient trials in the meta‐analysis.
Completion of this review is expected within one year of publication of this protocol on the Cochrane Library. It is also the intention of the review authors that a new search for RCTs will be performed two yearly and the review updated accordingly.
