This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn.

High-level disinfection of laparoscopic disposable plastic trocars with 2% alkalinised glutaraldehyde solution.

Primary prevention.

Cost-effectiveness analysis.

The study population consisted of 30 female and 15 male patients who underwent laparoscopic cholecystectomy with the diagnosis of cholecystitis.

Clinic of Gastrointestinal Surgery, Turkiye Yuksek Ihtisas Hospital, Ankara, Turkey

No dates for effectiveness, resource use or price data are specified.

The estimate of effectiveness was derived from a single study.

The effectiveness results were estimated to be equivalent and a cost consequences analysis was performed retrospectively on the same patient sample as that used in the effectiveness analysis.

The sample consisted of 45 patients (15 male and 30 female with a mean age of 48 years). Patients were randomly allocated to the intervention group (n=30) and the control group (n=15), but no details were provided regarding the method of randomisation. No power calculations were performed to determine the sample size. Written informed consent for participation was obtained in all cases.

The study was a single-centre, randomised, controlled trial. The decision whether to use disinfected or disposable trocars was made by a nurse but details of the criteria employed were not stated in the paper. The surgeons were blinded regarding the use of disinfected or new trocars.

The primary health outcomes estimated in the study were identifications of organisms in: samples of glutaraldehyde, trocar, laparoscope, umbilicus, bile, peritoneal lavage fluid, epigastric incision and umbilical incision. Identification of organisms was performed by classical methods. The patients were asked, on the seventh postoperative day, to check the trocar access site for infection. Wounds were assessed according to Cruse's criteria.

Gram-positive bacilli were isolated in one (3.3%) of the disinfected plastic trocars and in none of the new disposable trocars.

No culture positive results were found in the samples taken from laparoscope, glutaraldehyde, and epigastric incisions.

Culture positive results were obtained in 11 cases at the umbilicus (3 in the control group and 8 in the intervention group; non significant difference), in one case at the peritoneal lavage (in the control group) and in one case at the umbilical incision (in the control group).

None of the patients had infection at the wound site or intra-abdominally.

Disposable plastic trocars subjected to high-level disinfection can be reused safely without infection risk, but the preventive precautions for patients should be observed.

The results from the effectiveness analysis for the intervention and control groups were considered equivalent and thus, a cost-minimisation analysis was performed.

The direct costs considered were the costs of new and disposable trocars, scissors, Veress needles, and clip appliers. Discounting was not relevant due to the short period of analysis (less than 1 year). The source of the cost data was not stated and costs and quantities were not reported separately.

No statistical analysis was performed.

No indirect costs were considered.

US dollars ($).

No sensitivity analysis was performed.

A cost-minimisation analysis was performed after the effectiveness results for the intervention group were considered safe and without infection risks.

The total costs, if disposable trocars were used, would have been $18,600. Instead only 8 trocars were used with an expenditure of $1,240, thus savings of $17,360 were realised. Additional $22,000 savings were realised by the reuse of scissors, Veress needles, and clip appliers. Thus the overall savings were $39,360.

Costs and benefits were not combined due to the cost-minimisation approach adopted.

The authors concluded that disposable plastic trocars may be safely reused after high-level disinfection by 2% alkalinised glutaraldehyde solution, and that this is a very cost-effective method.

The choice of new disposable trocars in the comparator group was suitable for the objectives of the study although a case for sterilisation with ethylene is a possible alternative. Users of the database should consider whether the comparator used is the proper alternative in their own setting.

The lack of power calculation in determination of the sample size renders verification of the validity of the results difficult. In addition, concerns could be expressed regarding the selection of study participants (method not stated in the article) and the randomisation process of participants between the intervention and treatment arms.

The article does not state whether the costs of disinfection (materials and labour employed) were included in the analysis. The quantities of resources were not separately reported. The case for realised cost savings is valid provided that the intervention is safe and without risk of infection. The lack of rigorous cost analysis that would have included statistical or sensitivity analysis and the lack of a price year do limit the generalisability of the cost results.

The authors did make appropriate comparisons of their findings with those from other studies but did not address the issue of generalisability of the results to other settings and populations. The study sample appears to have been representative of the population considered.

The study confirms the safety results of analysis of the use of disinfected trocars but the sample size may not have been sufficiently large to validate the conclusions.

None stated.

Comment in: Journal of Laparoendoscopic & Advanced Surgical Techniques-Part A 1999;9(1):117-8.