Section 10.2: Surgical Wounds, Dehisced Incisions & Fistulas

Surgical Wounds, Dehisced Incisions & Fistulas

Surgical wounds represent a major portion of acute and chronic wound care consultations across inpatient surgical units, outpatient wound centers, and long-term care settings. While clean surgical incisions approximated with sutures or staples usually heal uneventfully, complications such as surgical site infections (SSIs), mechanical tension, breakdown (dehiscence), organ exposure (evisceration), and abnormal tract formation (enterocutaneous fistulas) create complex clinical challenges. ABWM CWS candidates must demonstrate expertise in surgical healing mechanisms, risk stratification, emergency evisceration protocols, and enterocutaneous fistula pouching techniques.

---

1. Intentions of Surgical Wound Healing

Wound healing after surgical intervention occurs through three distinct anatomical pathways, categorized by the timing and method of closure.

---

2. Surgical Wound Dehiscence & Evisceration

Dehiscence is defined as the partial or total separation of previously approximated surgical wound layers (epidermal, dermal, subcutaneous, or fascial). When dehiscence involves all layers of the abdominal wall, allowing abdominal viscera (most commonly small intestine) to protrude outside the abdominal cavity, the condition is termed evisceration.

Dehiscence Risk Factors & Etiologies

Dehiscence occurs when localized mechanical forces exceeding the tensile strength of the healing tissue or suture line coincide with impaired cellular repair. Key predisposing factors include:

1. Local & Infection Factors: Surgical Site Infection (SSI) is the leading cause of dehiscence. Bacterial pathogens release collagenases and proteases that degrade the newly synthesized fibrin-collagen matrix. Seroma or hematoma accumulation creates fluid pressure that separates tissue planes.
2. Mechanical Stress Factors: Sudden increases in intra-abdominal pressure from violent coughing, postoperative emesis, severe abdominal distension, ileus, or ascites place intense shearing tension on fascial closure lines.
3. Systemic & Host Factors:
   • Severe Malnutrition: Hypoalbuminemia (serum albumin < 3.5 g/dL) and low prealbumin (< 15 mg/dL) impair fibroblast proliferation and collagen synthesis.
   • Obesity (BMI > 30 kg/m²): Adipose tissue has poor vascularity, predisposing to localized fat necrosis and ischemia. Increased abdominal mass exerts constant outward tension on fascial sutures.
   • Diabetes Mellitus: Uncontrolled hyperglycemia impairs neutrophil chemotaxis, phagocytosis, and collagen cross-linking.
   • Immunosuppression & Steroid Use: Systemic corticosteroids inhibit inflammatory mediator release, macrophage recruitment, and fibroblast activation.
   • Advanced Age & Tobacco Use: Impaired microvascular perfusion and diminished tissue elasticity.

Clinical Presentation: The Warning Sign

The classic pathognomonic indicator of impending deep sub-fascial abdominal dehiscence is copious, salmon-colored (serosanguineous) wound drainage appearing between postoperative days 4 and 14. This fluid represents peritoneal fluid mixed with red blood cells leaking through a disrupted fascial layer beneath intact superficial skin sutures.

Emergency Evisceration Management Protocol

Evisceration is a surgical emergency requiring immediate bedside intervention while preparing the patient for emergency laparotomy:

1. Call for Immediate Surgical Assistance: Alert the operating room and surgical team.
2. Position the Patient: Place the patient in low Fowler's position (head of bed elevated 15–30 degrees) with flexed knees and hips. This position minimizes intra-abdominal pressure and reduces tension on the abdominal wall.
3. Protect the Viscera: Immediately cover the exposed bowel with sterile towels or gauze sponges saturated with warm sterile normal saline. DO NOT attempt to push protruded organs back into the abdominal cavity, as this risks bowel perforation and peritoneal contamination.
4. Maintain Moisture & Heat: Apply an occlusive sterile drape over the moist dressings to prevent heat loss and tissue desiccation.
5. Keep NPO & Support Hemodynamics: Withhold all oral intake, initiate intravenous fluid hydration, deliver supplemental oxygen, and monitor vital signs closely for septic or hemorrhagic shock.

---

3. Enterocutaneous Fistulas (ECFs)

An Enterocutaneous Fistula (ECF) is an abnormal epithelialized or tract-like conduit communicating between the lumen of the gastrointestinal tract and the cutaneous surface of the skin.

Etiology & Classification Systems

Approximately 75% to 85% of ECFs occur as iatrogenic complications of abdominal surgery (e.g., anastomotic breakdown, accidental enterotomy during lysing of adhesions, or erosion from abdominal drains/mesh). The remaining cases arise spontaneously from inflammatory bowel disease (Crohn's disease), radiation enteritis, abdominal malignancies, or penetrating trauma.

ECFs are primarily classified by daily volume of fluid output:

• Low-Output ECF: < 200 mL / 24 hours. Frequently originates from the distal ileum or colon. Carries a higher rate of spontaneous closure.
• Moderate-Output ECF: 200 to 500 mL / 24 hours.
• High-Output ECF: > 500 mL / 24 hours. Typically originates from the stomach, duodenum, or proximal jejunum. High-output fistulas drain caustic, enzyme-rich fluids, presenting high risks for severe electrolyte depletion, metabolic acidosis, hypovolemic shock, and rapid peristomal tissue breakdown.

Management Principles: The SNAP / SOW Protocol

Definitive surgical repair of an ECF is routinely delayed for 3 to 6 months after onset to allow resolution of severe intra-abdominal inflammation and dense peritoneal adhesions ("frozen abdomen"). Interim conservative management follows the SNAP protocol:

S — Skin Protection & Effluent Containment (SOW: Skin-barrier / Ostomy / Wound manager)
N — Nutrition Optimization & Fluid Balance (Restoring positive nitrogen balance)
A — Anatomy Delineation (Fistulogram, CT imaging to identify fistula origin)
P — Plan Definitive Surgery (Delayed 3–6 months for optimal healing)

Peristomal Skin Protection & Effluent Management (SOW)

Fistula effluent from the proximal GI tract contains concentrated sodium, potassium, bicarbonate, and digestive enzymes (trypsin, lipase, pepsin). When this effluent contacts skin, it causes rapid enzymatic digestion of the stratum corneum, leading to severe excoriation, denudation, and intense pain.

1. Skin-Barrier & Pouching Systems (SOW): Apply flexible hydrocolloid skin-barrier wafers, protective barrier rings, and moldable pastes to create an airtight seal around the fistula orifice. Custom pouches or flexible ostomy appliances with drainable ports allow continuous collection and accurate volume measurement.
2. Negative Pressure Wound Therapy (NPWT) with Fistula Isolation: For complex, high-output fistulas situated within open abdominal wounds, NPWT can be applied with specialized silicone fistula isolation rings or specialized pouch-ing-within-a-vacuum techniques. The isolation ring shields the fistula tract while negative pressure collects effluent and promotes surrounding granulation tissue growth.

---

Surgical Closure & Tissue Transfer (Grafts and Flaps)

Domain 3 also assesses surgical closure or tissue transfer. Match reconstructive complexity to defect depth, perfusion, contamination, and patient goals.

Pre-transfer checklist for the specialist: confirm arterial inflow/venous outflow, eradicate deep infection or osteomyelitis when feasible, optimize nutrition/glucose, eliminate dead space, and plan off-loading so the reconstruction is not destroyed by the original etiology (especially plantar DFU pressure). Postoperatively, monitor flap color, capillary refill, Doppler signals, and congestion; venous obstruction is an emergency.