Setting The study setting was tertiary care. The economic study was carried out in the USA.

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1 Laparoscopic intraperitoneal polytetrafluoroethylene (PTFE) prosthetic patch repair of ventral hernia: prospective comparison to open prefascial polypropylene mesh repair DeMaria E J, Moss J M, Sugerman H J Record Status 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. Health technology The use of a laparoscopic intraperitoneal polytetrafluoroethylene (PTFE) prosthetic patch (LIPP) for the repair of ventral hernia. An appropriate size of PTFE mesh was chosen to cover the fascial defect, with a 2 cm overlap of the fascial edges. The mesh was placed through a 10 mm trocar after four-quadrant-long sutures of nonabsorbable material were placed in the four quadrants of the material to facilitate the positioning of the patch. The patch was anchored to the fascia using a commercially available 5 mm tacking device. Type of intervention Treatment Economic study type Cost-effectiveness analysis. Study population The study population consisted of consecutive patients undergoing LIPP or OPPM repair. The mean age of patients was 46 years and the male to female ratio was similar in both groups: 8:13 for LIPP and 7:11 for OPPM. Setting The study setting was tertiary care. The economic study was carried out in the USA. Dates to which data relate The effectiveness data were for the period January 1996 to June The resource use data corresponded to the patients studied. The price year was not stated. Source of effectiveness data The estimates of effectiveness and resources used were derived from a single study. Link between effectiveness and cost data The costing was undertaken on the same patient sample as that used in the effectiveness study. It was not stated whether the costing was prospective or retrospective. Study sample No power calculations were reported. All patients undergoing ventral hernia repair as the primary surgical procedure, at the hospital where the study took place, were selected for inclusion in the study. Thirty-nine consecutive patients were studied, of which 21 underwent LIPP repair and 18 OPPM repair. No refusals to participate were reported. No loss to Page: 1 / 5

2 follow-up was reported. Study design The study was a single centre, non-randomised trial with concurrent controls, carried out in a tertiary care university hospital in an urban environment. The surgeon chose whether to perform LIPP or OPPM repair. The follow-up period was 12 to 24 months after surgery had been performed. No loss to follow-up was reported. Analysis of effectiveness The clinical data were analysed on an intention to treat basis. The primary health outcomes used in the analysis were the proportion of patients undergoing successful out-patient surgery, the proportion of patients needing post-operative parenteral narcotic therapy, subjective pain assessment and post-operative complications. It was unclear how the success of surgery was assessed, and the subjective pain assessment procedure was not reported. The groups were shown to be comparable at analysis in terms of age, gender and history of previous gastric bypass for obesity. The proportion of patients with history of previous ventral hernia repair was significantly higher for the LIPP group, i.e. 11 versus 3%, and more patients in the LIPP group had large hernia defects, 14 versus 8%, although this difference was not statistically significant. No adjustment for potential confounding factors was performed. Effectiveness results The hernia repair was successfully performed on an out-patient basis in 90% of LIPP cases and 7% of OPPM cases, (p<0.05). The need for parenteral narcotic therapy was significantly decreased for LIPP patients, 10 versus 79% for OPPM patients, (p<0.05). The subjective pain assessment showed that patients in the OPPM group experienced more pain than those in the LPPM group. The rate of complications and readmissions was not significantly different in the LIPP and OPPM groups, with the exception of an increase in the incidence of wound seromas in the LIPP repair group. The incidences of wound seromas were 43 and 22% in the LIPP and OPPM groups, respectively. Two major complications required re-operations; these were both found in patients in the LIPP group. The first required one readmission for surgical excision of the PTFE patch. The second required two readmissions with exploration and diversion for colocutaneous fistula, followed by colonic reanastomosis and repair of the hernia. The one case of hernia recurrence was found in a patient undergoing LIPP repair. Clinical conclusions Initial experience suggests that LIPP repair has advantages over OPPM repair in terms of decreased hospitalisation, post-operative pain and disability. Modelling No modelling was employed in the analysis. Measure of benefits used in the economic analysis No summary measure of benefits was used in the economic analysis. See the effectiveness results reported above. The economic analysis should be considered as a cost-consequences design since no measure of clinical benefit was identified. Page: 2 / 5

3 Direct costs The quantities and costs were generally not analysed separately, although the mean lengths of stay were reported separately. Direct costs included those for primary procedures and readmissions. Other direct costs included in the analysis were not reported. The costing was performed from a hospital perspective. Discounting of costs was not reported, although it may have been necessary in the case of readmissions. The estimates of quantities were based on actual data obtained from the study's participants. The source of the cost data was not provided and the price year was not stated. Statistical analysis of costs The data were compared between groups using Student's t-test, Fisher's exact test and the Wilcoxon rank sum test, as appropriate. A p-value of less than 0.05 was required for statistical significance. Indirect Costs Indirect costs were not included in the study. Currency US dollars ($). Sensitivity analysis No sensitivity analysis was reported. Estimated benefits used in the economic analysis Not applicable. See the effectiveness results above. Cost results The overall mean cost, i.e. initial plus readmission, was $11,013 plus $8,393 for the LIPP repair group and $13,600 plus $8,720 for the OPPM repair group. Synthesis of costs and benefits No synthesis of costs and benefits was performed. Authors' conclusions The initial results suggest that LIPP repair has advantages over OPPM repair in terms of decreased hospitalisation, postoperative pain, disability and overall cost. CRD COMMENTARY - Selection of comparators The selection of the comparator was justified. The OPPM repair technique was the traditional technique used for the repair of ventral hernia in the setting of the study. You, as a user of the database, should determine whether this is a widely used health technology in your own setting. Validity of estimate of measure of effectiveness The analysis was based on non-randomised study samples with the surgeon determining which repair technique to use; this is likely to introduce bias in the analysis of effectiveness. The authors argue that as more complex cases were selected for LIPP repair, the results in favour of LIPP repair may be even more meaningful. This is because the selection bias may introduce other unknown factors, which will differentiate the two study groups and therefore bias the Page: 3 / 5

4 results. The analysis of effectiveness suffered from additional problems, including: no preliminary sample size calculations were performed; no adjustments were made for the baseline factors where the groups were not comparable; and the apparent use of different follow-up periods. Finally, more detail should have been provided on the primary outcomes measured, in particular on the subjective pain assessment and on the definition of successful surgery. Validity of estimate of measure of benefit The authors did not derive a measure of health benefit. The analysis was, therefore, categorised as a cost-consequences design. Validity of estimate of costs Due to the lack of detail provided, it was not possible to assess whether all relevant categories of costs were included in the analysis, although all those relevant to the hospital perspective, i.e. the costs of the primary procedure and readmission, appear to have been included. This is likely to be problematic for assessing the quality of the costing results and for generalising the results to other settings. Another problem with the analysis of costs was the lack of discussion on discounting. For example, was it necessary. There was insufficient reporting of resource use and unit costs, and sensitivity analysis was lacking. Other issues Comparisons with other studies were not made, as, according to the authors, this was the first prospective study comparing the two repair techniques. The issue of generalisability to other settings was not addressed. The authors did not appear to present their results selectively. The authors' conclusions reflected the scope of the study. The authors did not report any further limitations to the study. Implications of the study The authors concluded that LIPP may become the procedure of choice for repair of ventral hernias, following refinements in the technique to reduce complications. Source of funding None stated. Bibliographic details DeMaria E J, Moss J M, Sugerman H J. Laparoscopic intraperitoneal polytetrafluoroethylene (PTFE) prosthetic patch repair of ventral hernia: prospective comparison to open prefascial polypropylene mesh repair. Surgical Endoscopy - Ultrasound and Interventional Techniques 2000; 14(4): Indexing Status Subject indexing assigned by NLM MeSH Adult; Aged; Biocompatible Materials; Comparative Study; Female; Hernia, Ventral /economics /surgery; Hospital Costs; Humans; Laparoscopy /economics /methods; Length of Stay; Male; Middle Aged; Peritoneum /surgery; Polytetrafluoroethylene; Postoperative Complications; Prospective Studies; Prosthesis Implantation; Recurrence; Reoperation; Surgical Mesh; Treatment Outcome AccessionNumber Page: 4 / 5

5 Powered by TCPDF ( Date bibliographic record published 31/01/2002 Date abstract record published 31/01/2002 Page: 5 / 5