To suture or not to suture?

NICE (2014) recommend that first-degree tears where the wound is not in apposition and all second-degree tears should be sutured (although if following suturing of the muscles the skin is opposed, it does not need to be sutured). However, Elharmeel et al (2011) suggest that small tears can heal well without being sutured and short-term outcomes are similar to sutured tears; long-term outcomes were not evaluated in the studies they reviewed and the sample sizes were small. They conclude there is insufficient evidence to recommend whether suturing or non-suturing is best practice and propose women should be offered information and informed choice around perineal suturing until conclusive studies are available. The Royal College of Midwives (RCM) (2008) suggest there appears to be neither benefit nor disadvantage in relation to suturing or not suturing the skin. Viswanathan et al (2005) advise it is preferable to leave both the superficial vaginal and perineal skin unsutured.

When discussing with the woman whether or not to suture, the midwife should discuss the rationale for suturing, with the advantages and disadvantages, to allow the woman to make a more informed choice. The advantages of suturing include quicker initial healing of the tissues with better wound alignment compared with not suturing (Langley et al 2006, Leeman et al 2007) and reduced urinary problems (Metcalfe et al 2006). However, suturing can be a painful procedure in itself, may require the use of lithotomy, which can be difficult for some women (e.g. those with pelvic girdle pain) and may result in increased use of analgesia (Langley et al 2006, Leeman et al 2007). Metcalfe et al (2006) found reported levels of perineal pain were similar between sutured and unsutured women.

Choice of suture material

Both non-dissolvable and dissolvable sutures have been used over the years to repair perineal trauma with the latter being more popular in recent years. Kettle et al (2010) suggest the ideal suture material should be one that causes minimal tissue reaction, be able to hold the tissues in apposition during the healing process and be absorbed once healing has occurred. While the sutures remain in the tissues, the body views them as foreign material which may cause a significant inflammatory response. If microorganisms colonize the implanted sutures or knots it can be difficult to eradicate any resulting infection which may predispose to abscess formation and wound dehiscence (Kettle et al 2010).

Catgut, made from purified collagen derived from the small intestine of cattle or sheep or from beef tendon, retains full tensile strength for 10 days. It causes an inflammatory response within the tissues causing the suture to be broken down by proteolytic enzymes and phagocytosis, although absorption times can be unpredictable, particularly in the presence of a wound infection of malnutrition (Kettle et al 2010). Subsequently, both chromic catgut (treated with chromate salts to prevent the catgut absorbing so much water, which slows down the absorption process and reduces the inflammatory reaction) and softgut (catgut impregnated with glycerol to make it remain more supple and prevent excessive drying) were introduced (Kettle et al 2010). Catgut is no longer available to the UK market, having been replaced with synthetic sutures, but is still used in non-European countries (Kettle et al 2010). Additionally, because low-cost chromic catgut is more readily available, it is likely to be continued as the preferred suture material for perineal repair in most poorly resourced settings (Peveen & Shabbir 2009).

Synthetic sutures include polyglycolic acid (e.g. Dexon), Polyglactin 910 (e.g. Vicryl) and Vicryl Rapide) and Biosyn. The polyglycolic acid suture is made of 100% glycolide and is converted into a braided suture material which is similar to Vicryl. Kettle et al (2010) advise it is designed to maintain wound support for up to 30 days and be completely absorbed by 120 days. Polyglactin 910 is a copolymer of glycolide (90%) and lactide (10%) which is derived from glycolic and lactic acids. They are also braided and coated with a copolymer of lactide, glycolide, and calcium stearate to reduce bacterial adherence and tissue drag (Kettle et al 2010). They are absorbed more quickly, by 90 days. Vicryl Rapide has the same chemical composition as Polyglactin 910 but is irradiated during the sterilization process creating a faster absorption rate of 42 days while providing wound support for 14 days (Kettle et al 2010). Biosyn is a newer monofilament product composed of glycolide (60%), dioxanone (14%) and trimethylene carbonate (26%). It provides wound support for up to 21 days and is fully absorbed between 90 and 110 days (Kettle et al 2010) although Medtronic suggest their product is fully absorbed by 56 days (Medtronic 2008). This suture has less tissue drag and less tissue reactivity and promotes better wound healing (Medtronic 2008, Kettle et al 2010).

So which is the best type of suture to use for perineal repair? Kettle et al (2010) suggest catgut increases short-term pain and wound dehiscence with an increased need to resuture compared to synthetic sutures but also advise that there is an increased need to remove synthetic sutures. For synthetic sutures, Kettle et al (2010) suggest there is little difference between Polyglactin 910 and Vicryl Rapide. Fewer sutures required removing in the first 3 months with Vicryl Rapide use but there was a slightly increased risk of superficial partial skin dehiscence causing the skin edges to gape (much less than with catgut) (Kettle et al 2010).

Wound dehiscence is associated with infection and provides a potential route for systemic infection with increased risk for septic shock. Infection causes the edges of the wound to become softened which can lead to the suture cutting out of the tissue and causing the wound to breakdown (Kettle et al 2010). Harper (2011) cites the case of a maternal death from sepsis following a second-degree tear which became infected.

Overall the fast-absorbing polyglactin sutures are currently considered to be the suture material of choice as they are associated with less perineal pain, a reduced need for analgesia, less uterine cramping at 24–48 hours and at 6–8 weeks, a significant reduction in the need for suture removal, fewer healing problems in the short term, and earlier resumption of sexual activity (Greenberg et al 2004, Leroux & Bujold 2006, Viswanathan et al 2005). Size 2/0 is indicated for perineal tissue.