Traumatic Abdominal Wall Hernia

Published on 19/07/2015 by admin

Filed under Radiology

Last modified 19/07/2015

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 High-energy injuries: Motor vehicle accidents constitute ∼ 50% of cases, with seat belts increasing risk

– “High-riding” seat belt incorrectly placed over abdomen increases risk (muscle avulsion from iliac crest)
– Other traumatic injuries are common (∼ 80%), with up to 50% of patients suffering other abdominal injuries requiring surgery
image Low-energy injuries (most common in children): Impact by small blunt object (such as bicycle handlebar, i.e., handlebar hernia)

– Hernias can develop after minor trauma in children

CLINICAL ISSUES

• May be overlooked clinically at time of injury and often diagnosed due to hernia-related complications

image Only 22% of patients in 1 series had TAWH diagnosed clinically, making CT essential to diagnosis
image Complications: Incarceration; bowel strangulation, perforation, and ischemia
• Peak incidence in children < 10 years of age due to handlebar injuries

image 2nd most common age group is 20-50 years due to motor vehicle accidents
• Treatment: Delayed repair of hernia usually performed 6-8 weeks following high-energy injuries to allow primary tissue damage to subside
image
(Left) Axial CECT demonstrates small bowel and colon image herniating through a traumatic abdominal wall defect. At surgery, several segments of small bowel had serosal tears and avulsions, requiring resection.

image
(Right) Axial CECT demonstrates a traumatic lumbar hernia, with herniated abdominal fat covered only by the latissimus dorsi muscle image. Also noted is infiltration of the intraabdominal fat image adjacent to the hernia. At surgery, a serosal tear of the descending colon was identified.
image
(Left) Axial CECT demonstrates a large amount of hypoenhancing small bowel image herniated through a traumatic hernia of the right abdominal wall. Active arterial bleeding image is evident. Much of the herniated bowel was not viable at the time of surgery.

image
(Right) Axial CECT shows disruption of the abdominal wall muscles image in the left lower quadrant, with the muscles avulsed from their attachment to the iliac crest. Note the presence of adjacent subcutaneous hematoma image. This is a typical example of a seat belt injury.

TERMINOLOGY

Abbreviations

• Traumatic abdominal wall hernia (TAWH)

Definitions

• Traumatic disruption of musculature and fascia of anterior abdominal wall due to blunt trauma (in absence of penetrating injury) ± herniation of bowel or visceral organs into subcutaneous space
• Handlebar hernia: Localized abdominal wall hernia caused by handlebar (or similar) injury

IMAGING

General Features

• Best diagnostic clue

image Development of new abdominal wall hernia in patient with recent blunt trauma (without penetrating injury)
• Location

image Roughly 75% occur in lower abdomen

– May reflect inherent weakness of lower abdomen due to natural orifices (such as inguinal canals) and susceptibility to increased intraabdominal pressures
image Equally common in right and left sides of abdomen
image Common locations include

– Region of iliac crest in seat belt injury (site of lap and shoulder strap junction)
– Focal hernias often occur in lower abdomen lateral to rectus sheath or inguinal region
– Larger, diffuse abdominal wall defects most often sustained in motor vehicle accidents
– Rarely, hernias may occur through tear in retroperitoneum
• Size

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