Surgical wounds: Strategies for minimizing complications

September 1, 2012
Pedro F. Escobar, MD
Pedro F. Escobar, MD

,
Jason Knight, MD
Jason Knight, MD

A look at how to minimize complications arising from surgical wounds.

Key Points

Wound infection and suprafascial wound separation are common events that result in readmission in 1% of women who undergo cesarean delivery.1 Wound infection complicates 1.5% to 3.8% of cesarean deliveries, whereas suprafascial wound separation complicates 3.6% of cesarean deliveries1-3 In patients undergoing abdominal hysterectomy, incidence of wound infection is as high as 11%, whereas approximately 2% have suprafascial wound separation.4,5

Fascial dehiscence is rare, complicating 0.4% of total abdominal hysterectomies.6 In several series, it was not observed after obstetric or gynecologic procedures in which a Pfannensteil incision was used.7,8 Risk of wound infection is lower with a laparoscopic approach than with abdominal hysterectomy (OR 0.31; 95% CI 0.12-0.77), with the largest series demonstrating a wound infection rates of 3% versus 22%, respectively.9,10 In a systematic review, incidence of trocar site hernia was estimated to be 0.5%.11

Factors associated with wound complications can be categorized as host-related or unrelated. Host-related risk factors include comorbidities such as diabetes, obesity, poor nutritional status, and smoking. Factors unrelated to the host typically involve the perioperative environment: adequacy of skin preparation, preoperative antibiotics, and postoperative wound care. This article discusses how optimizing these factors, to the extent possible, will increase the likelihood of uneventful wound healing.

Poorly controlled diabetes mellitus (DM), obesity, malnutrition, smoking, and immune compromise have all been demonstrated to be independent risk factors for wound complications.12 Wound complications-and most notably infection and wound breakdown-are more common in obese patients and 2-fold more prevalent in those with DM.13 Tight glycemic control during the perioperative period is associated with decreased incidence of wound complications.14 Hyperglycemia is associated with decreased cytokine expression and delayed re-epithelialization, conditions that conceivably increase wound infection risk.15 The independent association between obesity and increased risk of wound complications is more difficult to explain. Nonetheless, among obstetric and gynecologic patients, increasing thickness of subcutaneous tissue is associated with increased risk of wound infection.4,16 Smoking is a risk factor for wound infection, with an odds ratio of 1.2 (CI 1.14-1.32).17 It has been shown to decrease oxygen tension within the wound bed, a putative mechanism for the observed association between smoking and SSI.18

Malnutrition is often encountered in patients with advanced gynecologic malignancy but rarely in women undergoing benign obstetric and gynecologic procedures. Serum albumin levels are a reliable marker of nutritional status, and perioperative hypoalbuminemia is associated with increased incidence of wound complications and perioperative morbidity.19 Nutrition therapy to facilitate wound healing should be considered for patients who cannot tolerate oral nutrition within 7 days of surgery.20

Pregnancy is not considered a risk factor for wound complications, but it is worth acknowledging that its attendant hormonal milieu may impact the body's response to surgical wounds. Both estrogen and progesterone impact wound healing. Estrogen inhibits macrophage inhibiting factor (MIF), a potent pro-inflammatory protein. In mice, hypoestrogenism with overexpression of MIF results in excessive wound inflammation and poor wound healing.21 The role of progestins in wound healing is less clear. Progesterone has been associated with cytokine response to injury, and in one mouse study, progesterone supplementation improved wound healing in castrated female mice.22 Serum cortisol levels more than double by 26 weeks' gestation.23 Chronic steroid use in humans and pulsed steroid administration in mice are associated with increased wound failure rates.24,25

Studies in rats demonstrate that wounds occurring during pregnancy heal with less tensile strength than those in non-pregnant rats.26 Whether these observations suggest a clinically significant difference in wound healing during pregnancy in humans has yet to be determined. Well-controlled comparisons of surgical wound morbidity in pregnant versus non-pregnant women are lacking, but data derived from 183 laparoscopic appendectomies performed during pregnancy revealed no hernias and only one wound infection.27