What is the aim of this review?
The aim of this review was to find out whether subcuticular sutures (stitches placed under the skin) are effective for closing wounds after surgery. We were interested in all types of surgery except obstetric surgery (operations related to childbirth, e.g. caesarean sections). Cochrane researchers collected and analysed all studies related to this question and found 66 relevant randomised controlled trials. Randomised controlled trials are medical studies where patients are chosen at random to receive different treatments. This type of trial provides the most reliable health evidence.
In terms of wound infection following surgery, there is no clear difference between stitches that go under the skin and other methods of closing surgical wounds, such as standard stitches that go over the skin, surgical tape, staples, or glue. Stitches that go under the skin probably reduce wound complications compared with staples and improve patient satisfaction compared with stitches that go over the skin or staples. However, glue may improve patient satisfaction, and stitches that go over the skin and staples may be quicker for surgeons.
What was studied in the review?
Surgeons have various options for closing surgical wounds at the end of an operation. Skin closure can be carried out with stitches (sutures) that go under the skin, stitches that go over the skin, staples (clips), tissue adhesives (glue), tapes or other devices. Sutures can be absorbable (the stitches dissolve into the body as part of the healing process and do not need removing) or non-absorbable (the stitches need removing once the wound has healed).
Surgical site infections are a common problem after surgery and can cause a range of problems for patients. Surgical wounds can also cause unsightly scars if they do not heal correctly. We wanted to find out how stitches that go under the skin compare with other methods of closing surgical wounds in terms of infection, scarring, patient satisfaction, cost, pain, length of hospital stay and quality of life.
What are the main results of the review?
In March 2019, we searched medical databases and identified 66 studies that compared stitches that go under the skin with other methods of skin closure such as standard stitches, skin staples, tissue adhesive, tape, or surgical zippers. Sixty-four of these studies (involving 7487 participants) were used in our analysis. On average, each study involved 115 people. Most participants were adults (20 to 75 years) undergoing surgery in a hospital setting. Most studies did not state funding sources.
The majority of studies compared stitches that go under the skin with standard stitches, skin staples or tissue adhesives.
The main outcome of interest was whether wounds became infected. There was no clear difference between stitches that go under the skin and other closure methods in the number of people whose wounds became infected.
Compared with stitches that go over the skin, stitches that go under skin probably improve patient satisfaction. There is evidence that stitches that go under the skin probably prevent wound complications and improve patient satisfaction compared with skin staples. Stitches that go under the skin may prevent wound breakdown (skin separation) compared with staples or tissue adhesives, but tissue adhesives may improve patient satisfaction. However, alternative methods may be quicker for surgeons to use than stitches that go under the skin. There was no clear difference between stitches that go under the skin and the alternative closure methods for re-closure, pain, length of hospital stay and quality of life.
The studies we analysed often involved small numbers of participants and, in many cases, were not reported in a way that meant we could be sure they had been conducted robustly. We cannot, therefore, make conclusive statements about the effectiveness of stitches that go under the skin, and for all comparisons except the comparison with staples, better quality research is needed to form stronger conclusions.
How up to date is this review?
We searched for studies that had been published up to March 2019.
There is no clear difference in the incidence of SSI for subcuticular sutures in comparison with any other skin closure methods. Subcuticular sutures probably reduce wound complications compared with staples, and probably improve patient satisfaction compared with transdermal sutures or staples. However, tissue adhesives may improve patient satisfaction compared with subcuticular sutures, and transdermal sutures and skin staples may be quicker to apply than subcuticular sutures. The quality of the evidence ranged from high to very low; evidence for almost all comparisons was subject to some limitations. There seems to be no need for additional new trials to explore the comparison with staples because there are high-quality studies with large sample sizes and some ongoing studies. However, there is a need for studies exploring the comparisons with transdermal sutures, tissue adhesives, tapes and zippers, with high-quality studies and large sample sizes, including long-term assessments.
Following surgery, surgical wounds can be closed using a variety of devices including sutures (subcuticular or transdermal), staples and tissue adhesives. Subcuticular sutures are intradermal stitches (placed immediately below the epidermal layer). The increased availability of synthetic absorbable filaments (stitches which are absorbed by the body and do not have to be removed) has led to an increased use of subcuticular sutures. However, in non-obstetric surgery, there is still controversy about whether subcuticular sutures increase the incidence of wound complications.
To examine the efficacy and acceptability of subcuticular sutures for skin closure in non-obstetric surgery.
In March 2019, we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE (including In-Process & Other Non-Indexed Citations); Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting.
All randomised controlled trials which compared subcuticular sutures with any other methods for skin closure in non-obstetric surgery were included in the review.
Two review authors independently identified the trials, extracted data and carried out risk of bias and GRADE assessment of the certainty of the evidence.
We included 66 studies (7487 participants); 11 included trials had more than two arms. Most trials had poorly-reported methodology, meaning that it is unclear whether they were at high risk of bias. Most trials compared subcuticular sutures with transdermal sutures, skin staples or tissue adhesives. Most outcomes prespecified in the review protocol were reported. The certainty of evidence varied from high to very low in the comparisons of subcuticular sutures with transdermal sutures or staples and tissue adhesives; the certainty of the evidence for the comparison with surgical tapes and zippers was low to very low. Most evidence was downgraded for imprecision or risk of bias.
Although the majority of studies enrolled people who underwent CDC class 1 (clean) surgeries, two-thirds of participants were enrolled in studies which included CDC class 2 to 4 surgeries, such as appendectomies and gastrointestinal surgeries. Most participants were adults in a hospital setting.
Subcuticular sutures versus transdermal sutures
There may be little difference in the incidence of SSI (risk ratio (RR) 1.10; 95% confidence interval (CI) 0.80 to 1.52; 3107 participants; low-certainty evidence).
It is uncertain whether subcuticular sutures reduce wound complications (RR 0.83; 95% CI 0.40 to 1.71; 1489 participants; very low-certainty evidence). Subcuticular sutures probably improve patient satisfaction (score from 1 to 10) (at 30 days; MD 1.60, 95% CI 1.32 to 1.88; 290 participants; moderate-certainty evidence). Wound closure time is probably longer when subcuticular sutures are used (MD 5.81 minutes; 95% CI 5.13 to 6.49 minutes; 585 participants; moderate-certainty evidence).
Subcuticular sutures versus skin staples
There is moderate-certainty evidence that, when compared with skin staples, subcuticular sutures probably have little effect on SSI (RR 0.81, 95% CI 0.64 to 1.01; 4163 participants); but probably decrease the incidence of wound complications (RR 0.79, 95% CI 0.64 to 0.98; 2973 participants). Subcuticular sutures are associated with slightly higher patient satisfaction (score from 1 to 5) (MD 0.20, 95% CI 0.10 to 0.30; 1232 participants; high-certainty evidence). Wound closure time may also be longer compared with staples (MD 0.30 to 5.50 minutes; 1384 participants; low-certainty evidence).
Subcuticular sutures versus tissue adhesives, surgical tapes and zippers
There is moderate-certainty evidence showing no clear difference in the incidence of SSI between participants treated with subcuticular sutures and those treated with tissue adhesives (RR 0.77, 95% CI 0.41 to 1.45; 869 participants). There is also no clear difference in the incidence of wound complications (RR 0.62, 95% CI 0.35 to 1.11; 1058 participants; low-certainty evidence). Subcuticular sutures may also achieve lower patient satisfaction ratings (score from 1 to 10) (MD -2.05, 95% CI -3.05 to -1.05; 131 participants) (low-certainty evidence). In terms of SSI incidence, the evidence is uncertain when subcuticular sutures are compared with surgical tapes (RR 1.31, 95% CI 0.40 to 4.27; 354 participants; very low-certainty evidence) or surgical zippers (RR 0.80, 95% CI 0.08 to 8.48; 424 participants; very low-certainty evidence). There may be little difference in the incidence of wound complications between participants treated with subcuticular sutures and those treated with surgical tapes (RR 0.90, 95% CI 0.61 to 1.34; 492 participants; low-certainty evidence). It is uncertain whether subcuticular sutures reduce the risk of wound complications compared with surgical zippers (RR 0.55, 95% CI 0.15 to 2.04; 424 participants; very low-certainty evidence). It is also uncertain whether it takes longer to close a wound with subcuticular sutures compared with tissue adhesives (MD -0.34 to 10.39 minutes; 895 participants), surgical tapes (MD 0.74 to 6.36 minutes; 169 participants) or zippers (MD 4.38 to 8.25 minutes; 424 participants) (very low-certainty evidence). No study reported results for patient satisfaction compared with surgical tapes or zippers.