Effects of Mass vs Layered Closure on Incisional Surgical Site Infection Risk

Heart valve replacement surgery, operating room, Reykjavik, Iceland
Researchers conducted a study to compare the effects of mass vs layered closure on the risk for incisional surgical site infections among patients undergoing laparotomy via upper abdominal transverse incisions.

Compared with mass closure, layered closure of upper abdominal transverse incisions was independently associated with fewer incisional surgical site infections (SSI), according to study results published in Annals of Surgery.

In this interim analysis of an ongoing randomized controlled trial (ClinicalTrials.gov identifier: NCT03561727), researchers randomly assigned 268 patients undergoing laparotomy via upper abdominal transverse incisions in a 1:1 fashion to either mass or layered abdominal closure with continuous sutures. All patients were enrolled at a single-center in Warsaw, Poland between September 2018 and October 2020. The primary endpoint was incisional SSI, and patients were followed until November 2020. Characteristics of patients in both groups were similar, with the exception of sex, American Society of Anesthesiology (ASA) scores, transfusions, and thyroid disorders.

The researchers found that incisional SSI occurred more frequently among patients in the mass closure group vs those in the layered closure group (17.9% vs 6.0%; P =.004), with a relative risk reduction of 66.5%. In addition, the median duration of the procedure was increased among patients who underwent layered closure vs those who underwent mass closure (27.5 min vs 25.0 min; P =.044). Compared with patients in the mass closure group, the suture-to-wound length ratio was increased among those in the layered closure group (5.6 vs 8.1, respectively; P <.001). Of note, the rates of fascial dehiscence, mortality, severe morbidity, organ-space SSI, and length of postoperative hospitalization did not significantly differ between the groups.

Compared with mass closure, layered closure was found to be independently associated with a decreased risk for incisional SSI (odds ratio, 0.29; 95% CI, 0.12-0.69; P =.005). This independent effect of layered closure also was observed in multivariable analyses, which included covariates such as age, sex, BMI, ASA score, diabetes, smoking history, chronic obstructive pulmonary disease, preoperative laboratory parameters, chemotherapy, wound status, transfusions, and operative time.

This study was limited by its single-center design. In addition, these findings may not be generalizable to other populations as 77.2% of included patients underwent liver resection and those with BMIs greater than 35 kg/m2 were excluded.

“Incisional SSI rate may be considered an important indicator of technique efficacy in the absence of any other reliable data [regarding the] closure of transverse incisions” the researchers concluded.


Grąt M, Marcin M, Krasnodębski M, et al. Incisional surgical site infections after mass and layered closure of upper abdominal transverse incisions: first results of a randomized controlled trial. Ann Surg. 2021;274(5):690-697. doi: 10.1097/SLA.0000000000005128