Health Technology Assessment of laparoscopic compared to conventional surgery with and without mesh for incisional hernia repair regarding safety, efficacy and cost-effectiveness.

Introduction: Incisional hernias are a common complication following abdominal surgery and they represent about 80% of all ventral hernia. In uncomplicated postoperative follow-up they can develop in about eleven percent of cases and up to 23% of cases with wound infections or other forms of wound complications. Localisation and size of the incisional hernia can vary according to the causal abdominal scar. Conservative treatment (e. g. weight reduction) is only available to relieve symptoms while operative treatments are the only therapeutic treatment option for incisional hernia. Traditionally, open suture repair was used for incisional hernia repair but was associated with recurrence rates as high as 46%. To strengthen the abdominal wall and prevent the development of recurrences the additional implantation of an alloplastic mesh is nowadays commonly used. Conventional hernia surgery as well as minimally invasive surgery, introduced in the early 90s, make use of this mesh-technique and thereby showed marked reductions in recurrence rates. However, there are possible side effects associated with mesh-implantation. Therefore recommendations remain uncertain on which technique to apply for incisional hernia repair and which technique might, under specific circumstances, be associated with advantages over others.

Objectives: The goal of this HTA-Report is to compare laparoscopic incisional hernia repair (LIHR) and conventional incisional hernia repair with and without mesh-implantation in terms of their medical efficacy and safety, their cost-effectiveness as well as their ethical, social und legal implications. In addition, this report aims to compare different techniques of mesh-implantation and mesh-fixation as well as to identify factors, in which certain techniques might be associated with advantages over others.

Methods: Relevant publications were identified by means of a structured search of databases accessed through the German Institute of Medical Documentation and Information (DIMDI) as well as by a manual search. The former included the following electronic resources: SOMED (SM78), Cochrane Library - Central (CCTR93), MEDLINE Alert (ME0A), MEDLINE (ME95), CATFILEplus (CATLINE) (CA66), ETHMED (ED93), GeroLit (GE79), HECLINET (HN69), AMED (CB85), CAB Abstracts (CV72), GLOBAL Health (AZ72), IPA (IA70), Elsevier BIOBASE (EB94), BIOSIS Previews (BA93), EMBASE (EM95), EMBASE Alert (EA08), SciSearch (IS90), Cochrane Library - CDSR (CDSR93), NHS-CRD-DARE (CDAR94), NHS-CRD-HTA (INAHTA) as well as NHSEED (NHSEED). The present report includes German and English literature published until 31.08.2005. The search parameters can be found in the appendix. No limits were placed on the target population. The methodological quality of the included clinical studies was assessed using the criteria recommended by the "Scottish Intercollegiate Guidelines Network Grading Review Group". Economic studies were evaluated by the criteria of the German Scientific Working Group Technology Assessment for Health Care.

Results: The literature search identified 17 relevant medical publications. One of these studies compared laparoscopic and conventional surgery with and without mesh for incisional hernia repair, while 16 studies compared laparoscopic and conventional surgery with mesh for incisional hernia repair. Among these studies were 14 primary studies (one randomised controlled trial (RCT), two systematic reviews and one HTA-Report. The only study comparing laparoscopic and conventional surgery without mesh found substantial differences in terms of baseline characteristics between treatment groups. The outcome parameters showed decreased recurrence rates for the laparoscopic repair and similar safety of the procedures. Studies comparing laparoscopic and conventional surgery with mesh found similar outcome in terms of medical efficacy and safety. However, there was a trend towards lower recurrence rates, length of hospital stay, and postoperative pain as well as decreased complication rates for laparoscopic repair in the majority of studies. The impact of the technique of mesh-implantation and -fixation as well as the impact of certain factors on the choice of technique has not been systematically assessed in any of the studies.

Discussion: All identified studies suffer from significant methodological weaknesses, such as differences between treatment groups, mainly due to the non-randomised study design, small treatment groups causing low case numbers and lack of statistical power as well as the neglect of important risk factors or adjustment for those. Therefore, no conclusive differences could be identified concerning compared operative techniques, mesh-implantation and -fixation techniques or certain risk factors. Only the comparison of laparoscopic and conventional technique with mesh provides some evidence for a trend towards similar or slightly improved outcome in terms of medical efficacy and safety for the laparoscopic technique. However, there is still a great need for further research to investigate these questions. Basically, there is no full economic evaluation focussing on the relevant alternatives. Cost compareisons were available, even though only briefly attached to clinical research results. None of the studies primarily aimed to investigate costs or even cost-effectiveness.

Conclusion: When deciding on the choice of operative technique for incisional hernia repair, surgeons take various considerations into account, including patient characteristics, hernia characteristics and their own experience. The studies included in this HTA did not provide conclusive evidence to answer the research questions. Nonetheless, laparoscopic surgery demonstrated a trend towards similar or slightly improved outcome following incisional hernia repair. However, for more conclusive recommendations on the choice of operative technique, high quality trials are required From the economic perspective, alternative methods are not yet assessed. Only five of the studies involve a cost analysis, though in an insufficient manner. None of the studies identified were laid out as a health economic evaluation. Hence, further research is strongly recommended.