Addressing parastomal herniation through biomechanical simulation.

PURPOSE: Parastomal hernia remains a significant source of post-operative morbidity. Existing surgical solutions have shown limited success while not addressing the biomechanics underpinning parastomal herniation. The primary objective was to examine the influence of stoma aperture shape on abdominal wall stress and tissue destruction. The secondary objective compared mesh designs with respect to abdominal wall stress. METHODS: Finite element analysis of an abdominal wall model was used to simulate various stoma and mesh designs. The outcome measures were abdominal wall (mmHg) pressure required to initiate tissue tearing, stress distribution and median and peak abdominal wall stress (N/m2). RESULTS: The simulation demonstrated that the cruciate stoma incision developed high stress concentration at the apices of the slit incisions. The circular stoma incision distributed stress uniformly. The circular stoma design was more resistant to tissue tearing. The Keyhole mesh design demonstrated the lowest median and peak stress at 17.32 and 28.01 N/m2. This was a statically significant reduction in stress compared to the Sugar Baker and no mesh designs (p < 0.001).There were no significant differences between the Keyhole mesh design and loose mesh designs as long as the loose mesh design aperture did not exceed 1.5 times the stoma aperture diameter (p = 0.223). CONCLUSIONS: This study has demonstrated that the shape of the fascia incision and mesh design have a significant impact on parastomal hernia formation. Novel designs can be used to optimise the stoma. The circular stoma and loose mesh designs are promising avenues for future research.

Have early postoperative complications from laparoscopic rectal cancer surgery improved over the past 20 years?

AIM: Laparoscopic rectal cancer surgery has been increasingly used since 1991 following the publication of the first case series. Since then, several studies have confirmed that laparoscopic surgery for rectal cancer is challenging with associated morbidity and mortality. The aim of this study was to determine if the rates of early postoperative complications in laparoscopic rectal cancer surgery have improved over the past 20 years. METHOD: A literature search of the EMBASE and MEDLINE databases between August 1991 and August 2011 was conducted using the keywords laparoscopy, rectal cancer and postoperative complications. Data were analysed using linear regression ANOVA performed in GNUMERICS software. RESULTS: Ninety-seven studies were included for analysis. Over the last 20 years there has been no significant change in the rate of any early postoperative complications (anastomotic leak, conversion, sexual, urinary or faecal dysfunction, wound infection, overall morbidity or mortality). However, in the last 3 years, the rate of positive resection margins has decreased significantly (P = 0.01). CONCLUSION: There was no evidence of a statistically significant change in early postoperative complications until 3 years ago. This may reflect the inherent morbidity associated with rectal surgery regardless of the approach used, the limitations of the current laparoscopic instrumentation or the relatively long learning curve. With increasing experience, a repeat analysis in the near future following the publication of ongoing randomized clinical trials might show improved outcomes.

Has laparoscopic colorectal surgery become more cost-effective over time?

BACKGROUND: Several studies have confirmed that laparoscopic colorectal surgery (LCS) has superior short-term outcomes when compared to open colorectal surgery. However, the evidence for cost-effectiveness of LCS is less clear. AIM: The aim of this study is to explore the cost-effectiveness of LCS over time since it was first developed in 1991. METHODS: Systematic review of the literature was conducted. Electronic databases (PubMed, ScienceDirect and Google Scholar) were searched for studies from 1991 to 2010 using the keywords "laparoscopic, colorectal surgery cost, economic evaluation". RESULTS: Fifteen economic evaluations met the inclusion criteria. The percentage cost difference between open and laparoscopic surgery varied widely between different studies. The general trend when observing all the included economic evaluations is that there is a moderate negative correlation between progression of time and the size of the cost gap between laparoscopic and open surgery (R-value=-0.44). This correlation is even stronger (R-value=-0.64, P=0.046) if the studies are subdivided by the country where the surgery was carried out in. Western healthcare systems, even though they had a heterogeneous set of results (SD=27%), showed a decline in costs of laparoscopic surgery with time. CONCLUSION: From the current trends, it is projected that the results of future economic evaluations will unequivocally show that laparoscopic surgery is cheaper than open surgery. The initial higher costs of laparoscopic surgery training may be worth the savings made in the long term if it is practised in settings where postoperative care is expensive.