Surgical Wound Complications

With Special Attention on the Morbidly Obese Cesarean Section Patient

Click here to see a slideshow of two patients with surgical wound complications.

A wound dehiscence represents a disruption or separation of the normal incisional healing process following surgery. The extent of the involvement may be superficial or partial when the skin and the subcutaneous tissue are involved, or deep and complete when the wound extends to the level of the fascia. 

Despite well-meaning preventive measures, surgical wound complications do occur. No single cause can account for this. Rather, a combination of known risk factors, preoperative comorbidities, surgical technique, postoperative care, and timely follow-up is responsible.

Early diagnosis, evaluation, and appropriate treatment with close follow-up are needed to avoid potential serious medical consequences. Unfortunately, these things do not always happen. At times there is a tendency of the surgeon or health care provider to minimize or underappreciate a surgical wound complication and miss the extent of the problem, which delays the appropriate treatment. Often the patient may downplay their condition hoping the problem will get better on its own, thus avoiding early detection.

Common causes leading to wound dehiscence in this patient population include deep soft tissue infection, wound seroma and/or hematoma, obesity with a body mass index greater than 40, diabetes, poor nutritional state, anemia, increased intra-abdominal pressure and repeat same-site surgical incisions. Additional factors include smoking, chronic obstructive pulmonary disease, steroid use, emergency surgery, intraoperative complications, and the need for transfusions.

The consequences of delayed treatment of a surgical wound complication are many: Serious wound infection, delayed healing, hospital readmission, the need for reoperation, a prolonged protracted recovery, and patient dissatisfaction.

A Closer Look at the Connection Between Obesity and Surgical Complications

There are anatomical reasons why morbidly obese people are at higher risk for surgical complications. The main functions of subcutaneous adipose tissue are insulation and thermoregulation along with caloric reserve and body contouring. Metabolically adipose tissue is relatively inactive, lacks resilience, and has limited tensile strength. Its poor vascularity results from a relative tissue hypoxia due to the high ratio of tissue mass to capillaries. Additionally, sleep apnea, which is common in the obese patient, indirectly leads to a decrease in tissue oxygenation.

This is important because a surgical incision causes localized tissue damage. The amount of damage is increased in an obese patient relative to the depth of the incision. This large and now damaged surface area of relatively hyper-perfused tissue produces edema, which is in part the etiology for seroma formation. Meticulous hemostasis is required to avoid hematoma formation. These common problems will compromise wound repair and healing.

Fascia consists of silvery-white sheets of supportive connective tissue primarily composed of protein collagen. It encloses the peritoneal cavity and surrounds all of the body's tissues and organs, providing support and stability. The fascia’s tensile strength arises from its structure: densely packed bundles of fibril chains attached to each other by cross-linkage forming a triple helix configuration woven together like rope. The bundles are oriented in a wavy directional pattern, which affords flexibility and is augmented by elastin fibers and myofibroblast cells. This stretchability of the fascia promotes durability and structural resistance to force and pressure. Fascia is relatively avascular, and once injured or surgically incised, heals by protein synthesis and collagen fibril production by the fibroblasts within the fascia. This is an ongoing process that requires continual remodeling. Once compromised and healed the fascia never regains its full original tensile strength.

A serious surgical complication is an evisceration, which occurs when there is a break in the supporting fascia and underlying peritoneum resulting in the protrusion of an intraperitoneal organ above the existing fascia. Although this is rare, it represents a surgical emergency and requires urgent repair.

Obesity can be viewed as a significant independent factor to predict surgical site infection and wound dehiscence. Initially, wound separation is often accompanied by serosanguineous drainage. Typically, local pain, tenderness, and periwound erythema is present. However, in the obese patient these classic signs and symptoms may not initially be present. This delay occurs if the pathological process is located deep within the extensive subcutaneous tissue and has not migrated to the surface. Chills and fever along with malaise arise late in presentation and indicate a diffuse underlying infection.

Treating a Dehisced Incision

Once a diagnosis is made the dehisced incision should be probed with a long cotton-tip applicator. Often a deeply loculated collection will be revealed and additionally this is a simple way to initially assess for fascial integrity. The applicator should hit a firm, intact fascial wound base. With an early evisceration the applicator will plunge deeply. A lower abdominal ultrasound can be used to further evaluate the situation.

Healing improves when the wound is completely opened. Often, this is not the case and the wound is merely packed. Enlarging the wound site allows for proper wound drainage, and the evacuation of any seroma, hematoma, or abscess if present. It also facilitates debridement and debulking of nonviable subcutaneous tissue. Tangential excision of the wound edge can also be performed along with complete removal of any undermining if present. This is important because undermining creates a dead space between the skin edge and the wound base, halting epithelial migration and causing the wound to stall. This necessary treatment often requires a return to the operating room with anesthesia; however, the procedure can occasionally be performed using local anesthesia in the outpatient clinic.

Negative pressure wound therapy (NPWT) is often indicated to treat a dehisced wound and wound preparation prior to the application of the wound VAC (3M) is essential to ensure a positive outcome. The wound VAC should be set at 75 mmHg to run continuously and changed on a Monday–Wednesday–Friday basis. The reason for this lower initial setting is to prevent capillary occlusion of the subcutaneous tissue which can occur with a higher setting. If there is an initial positive response with granulation tissue formation the VAC pressure can be increased in increments.

All wounds are colonized with bacteria; however, not all wounds are infected. Antibiotics are not indicated unless there is extensive bacterial invasion of the periwound causing a systemic response such as fever, chills, tachycardia, malaise, or positive blood culture. This is usually not the case if treatment is initiated early.

Appropriate absorptive dressings are important to assist with moist wound care. Gauze packing and the wet-to-dry dressings are no longer considered standard of care and are not recommended. The gauze dries out preventing drainage, is unable to adequately absorb inflammatory exudate, traumatizes the wound tissues when removed, and is painful to the patient. Dakin's solution, betadine and hydrogen peroxide are cytotoxic and should not be used. Close monitoring of the wound appearance, size, and drainage is necessary to assess healing progress and should be used to modify treatments if indicated.  

A high-protein diet supplemented with amino acid additives containing arginine should be employed. Vitamin C, a key component in collagen synthesis that assists in fascial repair, should be added to the diet. A special cesarean-section binder should be utilized to support the fascial repair and retract the overlying pannus away from the incision. This will aid in preventing moisture-associated skin damage, remove overlying pressure to the incision, and provide some comfort. Referral to an advanced wound care center is recommended.

A Guide to the Surgical Technique

Preoperative conditioning begins with skin hygiene utilizing a pH-balanced soap so as to not disrupt the skin's normal acid mantle. Appropriate diet and tight glycemic control in the patient with diabetes are essential. Preoperative OR antibiotic dosing needs to be adjusted to the patient's weight. Proper incision location and gentle handling of the tissues are important.

The use of electrocautery for the skin incision and dissection leads to increased tissue destruction resulting from an electrical current burn and significantly increases wound edema. Electrocautery should be used for point hemostasis.

Separate tissue layer closures are needed to obliterate potential dead space. Wound irrigation with saline only and not cytotoxic solutions should be used. Fascial closure should be performed with a tapered atraumatic needle and not a cutting needle. Sutures should be spaced 1.0 cm apart to avoid tight closure which can lead to tissue necrosis. In dealing with a reoperative Pfannenstiel incision, the original should be used, removing the avascular incisional scar. A newly located second incision should be avoided. This can create an ischemic skin bridge, which poses a problem with healing.

At the time of fascial closure, the quality of the fascia should be assessed and closure should not be placed with extreme tension. A biological mesh may be indicated to facilitate the closure. While not ideal, this may alleviate and evisceration complication and a possible future incisional hernia. Skin sutures should be placed 1 to 1½ cm apart to avoid skin edge necrosis.

Recently, the utilization of a disposable, one-time use NPWT dressing system has gained attention. It is applied over the wound at the end of surgery for use as a prophylactic measure for high-risk surgical patients. It can be utilized as the postoperative dressing for up to 1 week. A subcuticular skin closure should not be used as this creates an incisional seal, which negates the benefits of utilizing this NPWT system.

Skin retention sutures and closed hemoduct drainage are other options to consider depending upon the operative situation. If used, the retention sutures should be horizontal mattress sutures spaced 2.0 to 3.0 cm from the wound edge to avoid trauma and should not be tightly closed as to avoid localized ischemia. A closed suction drain is occasionally indicated. The purpose of the drain placement is to detect early bleeding, prevent fluid collection and assist in closing residual dead space within the subcutaneous tissue. The drain is not meant to prevent infection. It should be removed within 3 to 4 days of the procedure.

A cesarean-section binder should be employed. This differs from the traditional abdominal binder in that it is constructed to lift up a lower abdominal wall pannus rather than constricting it. Home support is mandatory to avoid excessive work and repetitive heavy lifting such as when caring for a newborn and other children at home. Early follow-up to inspect the wound is needed.

James V. Stillerman, MD, CWSP, FACCWS, is the Medical Director of Samaritan Medical Center for Advanced Wound Care in Watertown, NY. He is board certified in advanced wound care by the American Board of Wound Management and has 35 years of experience including vascular surgery. Dr. Stillerman is a board member for Hospice in Jefferson County, New York. Most recently, he received the SAWC Grand Rounds award for his poster presentation the treatment of enterocutaneuos fistulas. Dr. Stillerman has initiated a wound care lecture series for teaching the medial students and medical residents. He also provides lectures to many of the regional wound care centers. He is currently is developing a wound care treatment template to assist the emergency department, local nursing homes and hospital with wound care and prevention. He also consults via telemedicine as an adjunctive evaluation tool.

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