Principles= Prevention of incision hernias by primary closure of mid line laparotomies with the best-evidenced suture techniques.
Background:
Although many data from prospective studies have set some evidence-based principles to be adopted when closing mid line laparotomy incisions, these principles have not found a widespread implementation in the surgical community. Surgical practice continues to rely largely on tradition rather than high-quality level I evidence. Incision hernia after laparotomy for treatment of abdominal aortic aneurysm (AAA) has a high incidence of 10% to 37% depending on the method of follow up (clinically, with ultrasound or with CT scan) and the duration of follow up.
It is known that the surgical technique used to close the fascia in mid line laparotomies is an important parameter with regard to wound complications like wound infections and incision hernias. At this moment the best results in a prospective randomised clinical trial considering incisional hernia rates and wound infections, have been reported by the surgeons from the Sundsvall clinic in Sweden. Their technique using a suture to wound length ratio of at least 4/1 and using many small stitches will be described in the protocol as the "Principles Technique". We want to explore if these results can indeed prevent incision hernias significantly if implemented with training and tutoring.
Methodology:Vascular surgeons,who are not using the principles yet, but show an interest to learn the Principles, will be asked to monitor a cohort of AAA patients using their current sutures and surgical techniques. Some of the vascular surgeons will undergo training and if wanted, proctoring during the first procedures using the Principles. A cohort of 120 AAA patients will be closed according to the Principles and monitored. The results of these 120 patients will be compared to the control group consisting of patients closed with the conventional technique by non---trained surgeons. Study hypothesis and sample size calculation: Investigators might improve the incision hernia rate after AAA treatment through a mid line incision at 12 months by using the Principles from an estimated 25% in the conventionally closed patients to 10% in the patients closed using the Principles.
Calculation:
To show a decrease of 60% in the incision hernia rate at 12 months(25% vs 10% incision hernias at 12 months)with a power of 80% and a significance level of 5%, investigators need 100 evaluable patients at 12 months in each arm. To compensate a 20% lost to follow up, we have to include at least 120 patients before the "principles training" and 120 patients afterwards. So the trial will end inclusions when 120 AAA patients have been entered using the Principles. Most likely the control group will be larger than these 120 patients,depending on the number of vascular surgeons participating in the teaching course and the timing of this course.
Primary endpoint:The incidence of incision hernias at 12 months will be determined by clinical examination.
Data management and ownership:
The data will be collected on a paper form and will be introduced in a database (SPSS Statistics, IBM) from which statistical analysis will be made.
