Practice Essentials
Diaphragmatic injuries are relatively rare and result from either blunt trauma or penetrating trauma. Diagnosis and treatment are similar regardless of mechanism, although many management issues are specific to blunt trauma. [1] Symptoms of diaphragmatic injuries frequently are masked by associated injuries. The diaphragm is integral to normal ventilation, and injuries can result in significant ventilatory compromise. Diagnosis may not be obvious. It is made preoperatively in only 40-50% of left-sided and 0-10% of right-sided blunt diaphragmatic ruptures. In 10-50% of patients, diagnosis is not made in the first 24 hours. In only approximately 3% of cases, is the injury bilateral. Early deaths usually result from associated injuries rather than the diaphragmatic tear. Mortality ranges from 5 to 30%. [2, 3, 4, 5]
The physical examination should focus initially on airway, ventilation, and circulation, with concomitant management of airway, ventilatory, or circulatory compromise. Examination of the neck and chest should include a particular focus on findings of tracheal deviation (ie, mediastinal shift), symmetry of chest expansion, and absence of breath sounds (ie, lung displacement).
Chest radiography is the single most important diagnostic study and may show elevation of the hemidiaphragm, a bowel pattern in the chest, or a nasogastric (NG) tube passing into the abdomen and then curling up into the chest. Chest radiograph of a blunt left diaphragmatic injury often shows an abnormal or wide mediastinum, even when the aorta is normal. The mediastinum should be investigated because of the association with aortic injury discussed previously.
Ultrasonography is used commonly in trauma and may visualize large disruptions or herniation; however, it may miss small tears from penetrating injuries.
CT scanning is helpful but not 100% sensitive because of its poor visualization of the diaphragm. A diagnosis can be made if herniation of abdominal contents is visualized. In a study by the Northern French Alps Emergency Network, of 31 patients with blunt trauma diaphragmatic injury, chest radiographs were diagnostic in only 18 of 29 patients and CT scan in 26 of 29. In the stable trauma patient, contrast-enhanced abdominothoracic CT with reconstruction was found to lead to early diagnosis. [6]
Meticulous attention to management of the ABCs, as with all patients, is the cornerstone for prehospital management of diaphragmatic injuries. The diagnosis is rarely made in the field, and no specific prehospital treatment is required. Treat the associated injuries and ensure adequate airway control and ventilation if signs of respiratory distress are present.
Focus on resuscitating the patient. As in all trauma patients, the ABCs are most important. Ensure a patent airway, assist ventilation if required, and begin fluid resuscitation if necessary. Place an NG tube when possible, as this will help in diagnosis if the NG tube appears in the chest on chest radiograph. Aspiration of gastric contents also helps decompress any abdominal herniation and lessen the abdominoperitoneal gradient that favors herniation into the chest. Consider placing a chest tube to drain any associated hemothorax or pneumothorax. Perform this with caution to prevent injury to herniated abdominal contents within the pleural cavity.
Guidelines
The Eastern Association for the Surgery of Trauma published the following guidelines for traumatic diaphragmatic injuries [7] :
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In left thoracoabdominal stab wound patients who are stable and do not have peritonitis, laparoscopy is recommended over CT to decrease the incidence of missed diaphragmatic injury.
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In penetrating thoracoabdominal trauma patients who are stable without peritonitis in whom a right diaphragmatic injury is confirmed or suspected, nonoperative over operative management is recommended in weighing the risks of delayed herniation, missed thoracoabdominal organ injury, and surgical morbidity.
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In stable patients with acute diaphragmatic injuries, abdominal rather than thoracic approach is recommended to decrease mortality, delayed herniation, missed thoracoabdominal organ injury, and surgical approach-associated morbidity.
Pathophysiology
Currently, 80-90% of blunt diaphragmatic ruptures result from motor vehicle crashes (MVCs). Falls and other traumatic events rarely are implicated. The mechanism of rupture is related to the pressure gradient between the pleural and peritoneal cavities. Lateral impact from an MVC is 3 times more likely than any other type of impact to cause a rupture, since it can distort the chest wall and shear the ipsilateral diaphragm. Frontal impact from an MVC can cause an increase in intra-abdominal pressure, which results in long radial tears in the posterolateral aspect of the diaphragm, its embryologic weak point.
Review of the historical clinical literature, including the series of Carter et al [8] , reveals that the majority (80-90%) of blunt diaphragmatic ruptures have occurred on the left side. The less common right-sided ruptures were seen to have more severe associated injuries and result in greater hemodynamic instability. They required greater force of impact, possibly because the liver provides protection or because of a weakness in the left diaphragm. [9] An autopsy series, however, revealed that left- and right-sided ruptures occurred almost equally. Most likely, these ruptures do occur equally, but the more severe injuries associated with right-sided ruptures cause more deaths and thus a lower rate of patient survival until diagnosis in the hospital. The relative frequencies of right-sided (20-30%) and bilateral (5-10%) ruptures have increased each decade, probably because improvement in trauma care has increased survival rates of patients with significant injuries.
In MVCs, the direction of impact may determine if an injury occurs and on what side. The likelihood of injury is related directly to the direction of impact and the person's position in the car. Persons involved in an ipsilateral impact are more likely to sustain diaphragmatic injury, commonly on the ipsilateral side. In the United States and Canada, this is seen as left-sided injuries in drivers and right-sided injuries in passengers.
Blunt trauma typically produces large radial tears measuring 5-15 cm, most often at the posterolateral aspect of the diaphragm. In contrast, penetrating trauma can create small linear incisions or holes, which are less than 2 cm in size and may present late, after years of gradual herniation and enlargement.
Penetrating injuries to the chest or abdomen also may injure the diaphragm. This specific injury is seen commonly where penetrating trauma is prevalent. This occurs most often from gunshot wounds but can result from knife wounds. Typically, the wounds are small, although occasionally a shotgun blast or an impalement causes a large defect. [10, 11]
Epidemiology
Traumatic diaphragmatic rupture (TDR) is uncommon, with the incidence ranging from 1% to 8% in blunt trauma patients. Left-sided diaphragmatic injuries account for 60-70% of cases. These injuries are most commonly accompanied by injuries to the stomach, colon, and spleen. Right-sided injuries represent 30-40% and require higher energy (ie, high-speed motor vehicle collisions). They generally involve the liver or colon. Bilateral injuries are extremely rare, occurring in approximately 3% of the patients. [12]
Diaphragmatic injuries are often related to thoracic and abdominal organ injuries (aorta, kidney, hollow viscera, liver, lung, spleen, pelvic and rib fractures) and severe complications (deep vein thrombosis, pulmonary embolism, hemopneumothorax, pneumonia, respiratory distress, sepsis), with a mortality of 20% being reported. [12]
