Case Files Surgery, (LANGE Case Files) 4th Ed.

SECTION II. Clinical Cases

CASE 24

Following recovery from an exploratory laparotomy and repair of a colon injury caused by a gunshot wound to the abdomen, a 24-year-old man developed an infection in the superior portion of his wound that required local wound care. He was discharged from the hospital on postoperative day 10 and has returned approximately 2 weeks later for a follow-up visit to the outpatient clinic. The patient indicates that he has been doing well except for fluid drainage from his open midline abdominal wound. On physical examination, his temperature is 37.5°C (99.5°F), pulse rate 70 beats/min, blood pressure 130/80 mm Hg, and respiratory rate 18 breaths/min. The results of his cardiopulmonary examinations are within normal limits. Examination of the abdomen reveals a small amount of serosanguineous fluid from the superior aspect of his surgical incision. There is no redness, swelling, or tenderness around the incision. A 4-cm fascia defect in the superior aspect of the wound is present without signs of evisceration.

Images What are the complications associated with this condition?

Images What are the risk factors for this condition?

Images What is the best treatment?

ANSWERS TO CASE 24: Fascial Dehiscence and Incisional Hernia

Summary: A 24-year-old man presents with stable abdominal wound dehiscence 3 weeks following exploratory laparotomy for the treatment of traumatic injuries.

• Complications: Abdominal fascia dehiscence can lead to abdominal evisceration, the development of enterocutaneous fistulas, and the subsequent formation of incisional hernias.

• Risk factors: Contributing factors include technical failure of surgical techniques or anesthetic relaxation. The occurrence of a deep wound infection is contributory. Finally, patient factors include age more than 70 years, diabetes mellitus, malnutrition, and perioperative pulmonary disease.

• Best treatment: Local wound care, followed by elective repair of the fascia defect (incisional hernia) at a later time.

ANALYSIS

Objectives

1. Recognize the contributing factors and preventive measures for wound dehiscence and incisional hernias.

2. Learn the treatment of wound dehiscence and incisional hernias.

Considerations

Disruption of the fascia following an abdominal operation is referred to as fascial dehiscenceTwo factors guide the management of fascia dehiscence found in the early postoperative period: stability of the intra-abdominal contents and the presence or absence of ongoing infection. In this patient’s case, the dehiscence appears stable and without risk of evisceration. This opinion is based on the appearance of the wound and the event occurring 3 weeks after the initial surgery when fibrous scar formation should be sufficient to prevent abdominal evisceration. With the absence of symptoms, fever, and local infection, it is unlikely that an ongoing infectious process exists; however, the complete evaluation should include a leukocyte count with a differential. The treatment of stable wound dehiscence consists of local wound care. The patient needs to be advised that an incisional hernia will eventually develop and will require repair at a later time. Early reoperation is indicated for patients at risk for evisceration, enterocutaneous fistula, or uncontrolled sepsis.

APPROACH TO: Fascial Dehiscence and Incisional Hernias

DEFINITIONS

FASCIA DEHISCENCE: The disruption of fascia closure within days of an operation; this complication may occur with or without evisceration.

EVISCERATION: The presence of abdominal viscera (bowel or omentum) protruding through a fascial dehiscence or traumatic injury.

ENTEROCUTANEOUS FISTULA: A direct communication between the small bowel lumen and a skin opening. It can be the primary process leading to wound dehiscence, but this complication frequently develops from wound dehiscence and direct trauma to the underlying bowel. It can be a devastating complication leading to septic and metabolic derangements, long-term disability, and mortality.

INCISIONAL HERNIA: Delayed development of a fascia defect because of inadequate healing. For some patients this condition can remain undetectable for as long as 5 years after the operation.

ABDOMINAL WALL COMPONENT SEPARATION: This technique involves the separation of the anterior and posterior anterior abdominal fascial layers, followed by lateral release of the anterior fascial layer. Advancement of the anterior fascia for closure of a midline abdominal defect can then be accomplished. The advantage of this technique is that no prosthetic material is used so that infectious risks are low.

CLINICAL APPROACH

Physiology of Wound Healing

Fascial dehiscence and incisional hernias generally develop as a result of inadequate healing of the fascia closure after surgery. The phases of wound healing are the inflammatory, proliferation, and remodeling phases (Table 24–1). Numerous environmental and host factors can affect the wound-healing process (Table 24–2). An understanding of the temporal occurrence and clinical implications of wound-healing events helps with the appropriate management of these complications (Figure 24–1).

Table 24–1 • PHASES OF WOUND HEALING

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Table 24–2 • CLINICAL FACTORS AFFECTING WOUND HEALING

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Figure 24–1. Temporal relationships of wound repair and implications in management.

TREATMENT

Approximately 2% to 20% of patients who undergo abdominal surgery develop fascial defects, with the incidence increased fourfold in patients with wound infections. Factors contributing to dehiscence and hernia formation include the patient factors listed in Table 24–2, the technical characteristics listed in Table 24–3, and environmental factors such as tobacco smoking, which causes a decrease in collagen strength. It is generally believed that a significant proportion of fascial defects arise as a result of technical problems.

Table 24–3 • TECHNICAL FACTORS RELATED TO ABDOMINAL CLOSURE FAILURE

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Management

Fascial defects may be seen early in the postoperative course as drainage of serous or serosanguineous fluid from an otherwise normal wound or as development of a soft tissue mass beneath the incision. The discovery of significant fluid drainage from an abdominal incision should alarm the examiner to the possibility of fascia dehiscence. When this occurs in the early postoperative period, the initial management consists of opening of the skin incision and meticulously inspecting the wound and fascia. Depending on the precise timing and circumstances, the treatment may require an immediate return to the operating room for repair or initial local wound care with delayed repair of the hernia. Immediate surgery is indicated for evisceration, impending evisceration, and bowel exposure with a concern for enterocutaneous fistula formation, and untreated intra-abdominal infections. Factors favoring delayed management include a stable dehiscence with no exposed bowel and the risk of a “hostile” abdominal environment associated with reoperation at this time.

Incisional Hernia Repair

Unlike the repair of a groin hernia, the repair of an incisional hernia is associated with a high-wound infection rate (7%-20%) and a high-recurrence rate (20%-50%). Contributing to a poor outcome are the coexisting conditions that may have originally led to development of the hernia (wound infection, patient factors, and fascia weakness). Primary repair of an incisional hernia is performed infrequently because of the high rate of recurrence; therefore, whenever feasible, incisional hernias should be repaired with the placement of prosthetic material. The placement of polypropylene mesh in the peritoneal cavity can increase the risk of erosion into the hollow viscus and subsequent enterocutaneous fistula formation. Some of the newer products available include composite mesh containing expanded polytetrafluoroethylene (PTFE) on the inside and polypropylene on the outside. Most recently, biosynthetic prosthesis containing collagen harvested from cadavers or porcine sources have also become available for the repair of high-risk, contaminated wounds. Incisional ventral hernia repair can be accomplished either by open or laparoscopic approaches. The studies comparing open versus laparoscopic repairs have found reduced length of hospital stay and reduced wound complications and infections associated with the laparoscopic approach. The recurrence rates between the two repair approaches have been found to be similar.

COMPREHENSION QUESTIONS

24.1 Which of the following conditions has been shown to have detrimental effects on wound healing?

A. Obesity

B. Hyperthyroidism

C. C-reactive protein deficiency

D. Diabetes mellitus

E. Hypothyroidism

24.2 Five days following abdominal surgery, a patient is noted to have 30 to 40 mL of serosanguineous fluid draining from her midline laparotomy wound. Which of the following is the most appropriate management?

A. Reinforce the wound dressing and reassure the patient that it is a wound seroma that will resolve spontaneously.

B. Initiate antibiotic therapy.

C. Perform an immediate laparotomy.

D. Obtain a CT scan.

E. Open the wound to evaluate the fascia.

24.3 A 36-year-old nursing student undergoes a laparotomy for appendicitis and asks about the possibility of incisional hernia formation. Which of the following statements is true regarding incisional hernias?

A. The incidence may reach upward of 20% in infected wounds.

B. Repairs are generally associated with less than 2% recurrence.

C. Primary repair is associated with less infection and a lower recurrence rate.

D. Formation of a hernia is nearly always recognized within 3 months after surgery.

E. Incisional hernias do not develop in healthy patients without predisposing risk factors.

24.4 A 40-year-old man underwent celiotomy and lysis of adhesions for small bowel obstruction 8 days ago. He was discharged home on postoperative day 6. He returns to the outpatient clinic for follow-up. On examination he is noted to have a large amount of fluid drainage on his dressing. Which of the following would be helpful in differentiating abdominal wound dehiscence from enterocutaneous fistula?

A. Abdominal CT scan

B. Wound inspection for fascial defect

C. Blood sample for complete blood count analysis

D. Visual inspection of the drainage fluid

E. Bacterial culture of the fluid

24.5 Which of the following statements is most accurate of incisional hernia?

A. Laparoscopic approach to the repair of incisional hernia repair has lower rates of recurrence in comparison to open approaches.

B. The result of incisional hernia repair is more favorable than the outcome of inguinal hernia repair.

C. Incisional hernia recurrence is lower among patients who develop wound infections.

D. Early occurrence of incisional hernia following celiotomy is commonly associated with the onset of small bowel obstruction.

ANSWERS

24.1 D. Diabetes mellitus is associated with poor wound healing. Although obesity may predispose to wound separation and dehiscence, it does not lead to poor wound healing.

24.2 E. The drainage of a large amount of serosanguineous fluid is highly suggestive of fascia dehiscence; therefore, direct evaluation of the fascia should be performed. CT scan is not necessarily helpful in this situation because small fascial defects may not be visualized. Antibiotics are not necessary in this case because the characteristic of the drainage fluid does not suggest intra-abdominal infection.

24.3 A. The incidence of incisional hernia may approach 20% in infected wounds. Up to 20% to 50% of repairs may eventually fail. Primary repairs are seldom performed because of the high rate of hernia recurrence. Incisional hernias are contributed by a number of patient-related factors but also contributed by technical factors related to the abdominal operations.

24.4 D. Inspection of the drainage fluid may be helpful in differentiating fascia dehiscence from enterocutaneous fistula. Dehiscences are usually associated with the drainage peritoneal fluid that is serous or serosanguineous, while patients with enterocutaneous fistulas generally have drainage of enteric contents that is either bilious or feculent. Inspection of the wound would most likely show fascial defect and would not reliably differentiate the two processes. A CBC is helpful to suggest the presence or absence of occult intraabdominal infection. CT scan in this setting could help identify undrained fluid collections that may represent abscesses but does not reliably differentiate the two processes. Fluid bacterial cultures help identify possibilities of infections either from an intra-abdominal or subcutaneous source.

24.5 A. Incisional hernias could be repaired by open or laparoscopic approaches, and there is no difference in the recurrence rates between the two types of repairs. However, laparoscopic repairs appear to be associated with lower rates of wound complications and shorter length of hospital stay. The complications and recurrence rates of incisional hernia repair are higher than those associated with inguinal hernia repairs. Wound infections contribute to fascial destruction and dramatically increase the risk of incisional hernia development. While small bowel obstruction may increase abdominal pressure and contribute to incisional hernia development, this is a rare cause of incisional hernia.

CLINICAL PEARLS

Images The tensile strength of uncomplicated wounds steadily increases for approximately 8 weeks, when it reaches 75% to 80% of that of normal tissue; thereafter the wound continues to strengthen, but the strength never reaches that of uninjured tissue.

Images The use of braided, nonabsorbable suture material is associated with the entrapment of infected debris within the suture material and may lead to an increased number of infections. Therefore, this type of suture material should be avoided in the closing of an infected abdomen.

Images The 4:1 ratio refers to the optimal ratio of suture length to wound length that is required so that an adequate amount of tissue is incorporated into the fascia closure.

Images Reclosure of a previously healed fascial incision is associated with lower strength of healing and increased wound breakdown.

REFERENCES

Barbul A, Efron DT. Wound Healing. In: Brunicardi FC, Andersen DK, Billiar TR, et al, eds. Schwartz’s Principles of Surgery. 9th ed. New York, NY: McGraw-Hill; 2010:209-233.

Forbes SS, Eskicioglu C, McLeod RS, Okrainec A. Meta-analysis of randomized controlled trials comparing open and laparoscopic ventral and incisional hernia repair with mesh. Br J Surg. 2009;96:851-858.

Tufaro AP, Campbell KA. Incisional, epigastric, and umbilical hernias. In: Cameron JL, ed. Current Surgical Therapy. 9th ed. Philadelphia, PA: Elsevier Mosby; 2008:573-576.