Suture technique
Incisional hernias are the most common long-term complication after laparotomy (4). They have a reported frequency of 11-16% in the literature (13). The actual rate of incidence is probably much higher, given that up to 30% of these hernias remain asymptomatic (5).
The INSECT study published in 2009 (2) used a three-arm design to study the postoperative course of 625 patients after interrupted sutures vs. rapidly or delayed absorbable running loop sutures. No significant differences between the individual techniques were identified for the formation of incisional hernias or for other study criteria (abdominal wound dehiscence, wound infections, pulmonary complications). This study, too, demonstrated more postoperative abdominal wall hernias than previously suspected. The results range up to 25% per department. The INSECT study triggered intensive discussions since it was realized that to reduce the rate of incisional hernias awareness of the topic of abdominal wall closure had to be heightened.
Between 1998 and 2020, a total of 6 meta-analyses on this topic have been published. The papers of Weiland et al. and Hodgson et al. favor running sutures (3,6). In the following year Rucinski et al. also preferred running sutures, with the choice of suture material being the focus of the analysis (7). In 2002, Van't Riet et al. published a meta-analysis of midline laparotomies which for the first time compared interrupted with running fascial sutures. No significant difference in terms of incisional hernia formation was found. Most of the included studies nevertheless favored running sutures, arguing that they were faster and easier to place (8). Gupta et al. published similar results in 2008, but unlike in the previous meta-analyses, interrupted sutures were preferred for the first time (9). In a 2010 meta-analysis on this topic comparing running with interrupted sutures in elective primary and secondary midline laparotomy, Diener et al. judged running sutures as the better technique (10).
In general, despite differences in results and arguments, suture techniques in midline laparotomy tend to favor running fascial suture, at least in elective procedures.
Clinical trials by Israelsson (15,16) have demonstrated the prophylactic value of running sutures with a suture-to-wound length ratio of at least 4:1 in the prevention of incisional hernias following laparotomy closure. The effect of running sutures with the propagated ratio of at least 4:1 is due to a reduction of the tissue damaging tensile forces in each stitch and a large amount of "spare material" in the coils of the suture, preventing an inappropriate increase in suture tension when the abdomen is distended.
The negative impact of high suture tension on perfusion, collagen synthesis, and mechanical strength of the laparotomy wound has been established experimentally (17). Peritoneum, adipose tissue, and muscles provide only minimal retention strength for the suture material and become necrotic within hours under the suture tension, which contributes to the loosening of the suture material (18). Only the bradytrophic tissue of the fascia offers mechanical resistance (19).
“Small tissue” bites
Israelsson et al. were able to demonstrate, first in experimental studies (19) and then in randomized clinical trials (20), that the infection rates and incisional hernia formation could be reduced by an innovative "short stitch" technique by shortening the stitch distance to the wound edge from 10 mm to 5‑8 mm which reduces tissue trauma.
This trial demonstrated a twofold increase in the risk of wound infection and a fourfold increase in the risk of incisional hernias in the "long stitch" group.
Sutures
Numerous studies and meta-analyses have clearly shown the superiority of delayed-absorbable (including non-absorbable) versus rapidly absorbable suture material in the short-term (postoperative abdominal wound dehiscence) and long-term (incisional hernia) postoperative period (2,10).
However, non-absorbable materials result in a 48% higher rate of suture fistulas, as well as an increase in postoperative wound pain with permanent mechanical tissue irritation (7). For the running fascial sutures currently in favor, size 1 looped sutures should be preferred. With an interval of 1 cm between the stitches and a distance of 1 cm from the edge of the wound to the point where the stitch enters the fascia, this results in a suture length consumption of at least four times the length of the incision (10).
The skin may be closed with a variety of materials. There are no meaningful randomized studies. However, skin staples appear to have the lowest rate of infection in contaminated wounds (22).
Wound drains
At present, there is no general agreement on the importance of subcutaneous sutures and subcutaneous wound drains. Several trials have demonstrated a lower rate of subcutaneous hematomas, seromas, and wound infections after suturing the subcutaneous tissue. The benefit of drains could not be confirmed in the studies conducted thus far (10,11).
Peritoneal sutures
Separate peritoneal sutures are considered obsolete in abdominal surgery today. They do not contribute to the mechanical strength of the abdominal incision and lead to pain and adhesions in the laparotomy region, presumably via increased peritoneal necrosis (14,21).
Abdominal wound dehiscence
Burst abdomen is a postoperative complication with high morbidity and mortality.
Incidence figures range from 0.5% to 3% (23,24,25,26). Predisposing factors are either patient-related or due to the surgical technique or the surgeon. There is no consensus on the ideal technique or material for abdominal wall closure (27,34,35). In terms of the risk of abdominal wound dehiscence, mass closure of the abdominal wall is superior to layered closure (28,29). Lacking balanced tension from stitch to stitch, interrupted sutures seem to be inferior to the running sutures (27,28,30). One important causal aspect is the pathological increase in intraabdominal pressure resulting from ileus, paralysis, peritonitis, and hematomas (31). Abdominal wound dehiscence is a complication in the early postoperative phase. Most authors attribute suture line failure to the sutures cutting through the edge of the fascia into the incision itself (7,28,32). Burst abdomen can be treated by definitive closure of the abdominal wall or fashioning a pressure-relieving intestinal stoma with early selective abdominal wall closure (35,36).