Version May 2024
INTRODUCTION — Diaphragmatic injury is uncommon, representing less than 1 percent of all traumatic injuries [1,2]. The diaphragm is usually injured in association with other thoracic and abdominal organs. Although diaphragmatic injury can be obvious (eg, herniation of abdominal contents on chest radiograph), the injury may be subtle, and imaging studies can be nondiagnostic. A high index of suspicion needs to be maintained because delayed diagnosis is associated with an increased risk for herniation and strangulation of abdominal organs, which can be life-threatening. For patients in whom the diagnosis is uncertain, diagnostic laparoscopy, thoracoscopy, or open surgical exploration may be needed to establish the diagnosis. When identified, diaphragm injury is repaired with open surgical or minimally invasive techniques, the choice and timing of which depends upon the presence of associated injuries and the overall condition of the patient.
This topic will discuss the recognition and surgical management of blunt and penetrating injury to the diaphragm. Injuries to associated thoracic and abdominal organs are discussed in separate topic reviews. The general approach to blunt and penetrating chest and abdominal trauma is also discussed elsewhere. (See "Initial evaluation and management of blunt thoracic trauma in adults" and "Initial evaluation and management of penetrating thoracic trauma in adults" and "Initial evaluation and management of blunt abdominal trauma in adults".)
ANATOMY OF THE DIAPHRAGM — The diaphragm (dia: across, phragm: fence) is the musculotendinous boundary between the negative-pressure thoracic cavity and positive-pressure abdominal cavity. The diaphragm plays a significant role in respiratory mechanics, and injury to the diaphragm impairs ventilation and oxygen delivery. The normal mechanics of respiration are discussed elsewhere. (See "Chest wall diseases and restrictive physiology", section on 'Normal structure and function'.)
The diaphragm is dome-shaped and attaches to the chest and abdominal walls circumferentially (figure 1). The liver, spleen, transverse colon, stomach, pancreas, adrenal glands, and kidneys contact the undersurface of the diaphragm. Thoracoabdominal structures, including the aorta, inferior vena cava, thoracic duct, esophagus, vagus nerves, and phrenic nerves, traverse the diaphragm through three major apertures (ie, aortic, caval, esophageal) (figure 2).
The diaphragm is composed of two muscle groups, costal and crural, which are compositionally and functionally distinct. Both groups are innervated by the phrenic nerves (figure 3 and figure 4). The costal muscle group that forms the diaphragmatic leaflets is thin, and contraction of its fibers flattens the diaphragm and lowers the ribs. The crural muscle groups are thicker but contribute minimally to the displacement of the diaphragm. The median arcuate ligament anterior to the aortic hiatus is formed by the continuation of the medial tendinous margins of the crura.
The costal and crural fibers insert into the central tendon (figure 1). The anterior portion of the tendon attaches to the posterior aspect of the xiphisternal junction. The posterior portion of the central tendon attaches to the first three lumbar vertebral bodies (L1-L3). Lateral insertions of the central tendon occur on the 6th rib anteriorly and the 12th rib posteriorly.
The vascular supply of the diaphragm is derived from the phrenic artery below the diaphragm and the pericardiophrenic arteries above the diaphragm (figure 2). The phrenic nerve originates from the anterior rami of C3, C4, and C5 and traverses the neck and mediastinum before inserting into the diaphragm centrally (figure 3 and figure 4). The outer rim of the diaphragmatic muscle is innervated laterally from the T7 through T12 (figure 1). The crural group of muscles receives innervation from the vagus nerve [3].
Diaphragmatic injury severity scale — Diaphragm injuries are classified according to the American Association for the Surgery of Trauma (AAST) organ injury scale. Increased morbidity and mortality has been correlated with increasing injury grade for some injuries (eg, liver, spleen, kidney) but, to date, not for diaphragmatic injuries. The diaphragmatic injury severity scale is as follows:
●Grade I: Contusion
●Grade II: Laceration ≤2 cm
●Grade III: Laceration 2 to 10 cm
●Grade IV: Laceration >10 cm; tissue loss ≤25 cm2
●Grade V: Laceration and tissue loss >25 cm2
TRAUMA EVALUATION — The initial resuscitation, diagnostic evaluation, and management of the patient with blunt or penetrating injury are based upon protocols from the Advanced Trauma Life Support (ATLS) program, established by the American College of Surgeons Committee on Trauma. The initial resuscitation and evaluation of the patient with blunt or penetrating abdominal or thoracic trauma is discussed elsewhere. (See "Initial evaluation and management of blunt abdominal trauma in adults" and "Initial evaluation and management of blunt thoracic trauma in adults" and "Initial evaluation and management of abdominal stab wounds in adults" and "Initial evaluation and management of abdominal gunshot wounds in adults" and "Initial evaluation and management of chest wall trauma in adults".)
In the setting of acute trauma, many patients cannot relate their symptoms or medical history due to altered mental status (eg, neurologic injury, intoxication) or because they are intubated and sedated. Every attempt should be made to identify preexisting medical conditions by contacting the patient's primary care physician or family members. The presence of significant medical comorbidities and medical conditions requiring antiplatelet or anticoagulation should be determined, as these may impact management decisions.
RECOGNITION OF DIAPHRAGMATIC INJURY — Studies using the National Trauma Data Bank (NTDB), the largest trauma registry in the world, have found an overall incidence of diaphragm injury of 0.46 percent [4]. A suspicion for diaphragmatic injury begins with the identification of the injury mechanism, physical examination of the patient, and assessment of associated injuries. Certain injury patterns increase the risk for diaphragmatic injury.
Injury mechanism — The diaphragm can be injured directly, due to an impalement or missile passing through it from the abdominal cavity to the thoracic cavity or vice versa, or indirectly from blunt rupture, which is caused by a sudden increase in intra-abdominal pressure that is sufficient to overcome the strength of the diaphragmatic tissue. Blunt diaphragm rupture usually causes large radial tears of the diaphragm, while penetrating injury leads to smaller rents that approximate the size of the penetrating impalement. As such, penetrating injuries are more likely to be missed. In a review of the National Trauma Data Bank, among those with diaphragmatic injury, 33 percent had a blunt mechanism and 67 percent had a penetrating mechanism [4]. Compared with penetrating diaphragmatic injuries, patients with blunt injury were significantly older (44 versus 31 years) and had a higher injury severity score (33 versus 24). (See 'Delayed presentation' below.)
Penetrating injury — Penetrating mechanisms to the thoracoabdominal region, such as stabs, gunshot, shotgun, and impalements, account for approximately 65 percent of all diaphragmatic injuries [2]. The diaphragm can rise as high as the fourth thoracic (T4) dermatome on the right and the fifth dermatome (T5) (figure 5) on the left with expiration, and it descends to as low as the eighth thoracic dermatome (T8) with deep inspiration. The lowest level of the lateral diaphragm attachment is the base of the 12th rib. Thus, any impalement or missile that passes through the chest or abdominal wall from T4 through T12 has the potential to injure the diaphragm. Penetrating injury due to stabbing is more common on the left compared with the right, presumably because the majority of assailants are right-handed, assuming a frontal assault.
Blunt diaphragmatic rupture — Blunt mechanisms account for the remaining 35 percent of diaphragmatic injuries and occur in 0.8 to 1.6 percent of patients sustaining blunt trauma. Motor vehicle collisions are responsible for up to 90 percent of blunt diaphragm rupture, with the remainder due to falls or crush injury, both of which can sufficiently elevate intra-abdominal pressure to rupture the diaphragm [2,5,6].
When the diaphragm contracts, the relaxed dome-shaped diaphragm flattens, which increases the volume of the thoracic cavity, decreases the volume of the abdominal cavity, and changes intrapleural and intra-abdominal pressure. During normal quiet breathing, intraperitoneal pressure ranges from +2 to +10 cm water (H2O), and intrapleural pressure is from -5 to -10 cm water, which results in a pleuroperitoneal gradient of +7 to +20 cm H2O in the supine position. With maximal inspiration, the diaphragm is forced downward and the pleuroperitoneal pressure gradient can rise as high as +100 cm H2O. Changes in the compliance of the abdominal or chest wall alter normal mechanics. (See "Chest wall diseases and restrictive physiology", section on 'Normal structure and function'.)
The application of blunt force to the abdomen or chest can result in pleuroperitoneal gradients of +150 to 200 cm H2O, which exceeds the strength of the muscle or tendinous tissues and can rupture or avulse the diaphragm from its attachments. (See 'Anatomy of the diaphragm' above.)
The left diaphragmatic leaflet is two to three times more likely than the right leaflet to be injured with blunt trauma [7-9]. Bilateral blunt rupture of the diaphragm occurs in 2 to 6 percent of patients [10]. In one retrospective study of 731 patients with traumatic diaphragm rupture, the left posterolateral region medial to the spleen was the most common site of injury [9]. This is felt to be due to a congenital weakness of this region. Another explanation may be that the liver protects the right diaphragm by attenuating or preventing the transmission of force across the diaphragm. However, a tendency toward more right-sided diaphragmatic injuries is observed as collision speed increases [11].
Associated injuries — At least 50 percent of patients with diaphragmatic injury also suffer associated injuries [9,12].
For penetrating trauma, the passage of an impalement or missile through the abdominal or chest walls rarely injures the diaphragm in isolation [2,9]. In one study, 75 percent of patients with penetrating diaphragmatic injury had an associated organ injury [7]. In another study, an average of two organ injuries were present in patients who suffered stab wounds and three organ injuries in those patients sustaining gunshot wounds [8]. In a study from the National Trauma Data Bank (NTDB), penetrating diaphragmatic injury was associated with liver and hollow viscus injuries [4]. Compared with penetrating injury, patients with blunt injuries had more injuries to the thoracic aorta (2.9 versus 0.5 percent), lung (48.7 versus 28.1 percent), bladder (5.9 versus 0.7 percent), and spleen (44.8 versus 29.1 percent).
The percentage of patients with a given injury who also have a traumatic diaphragmatic rupture are: liver (48 percent), hemothorax and/or pneumothorax (47 percent), spleen (35 percent), rib fracture (28 percent), bowel (23 percent), kidney (16 percent), pelvic fracture (14 percent), closed head injury (11 percent), thoracic aorta (4 percent), and spinal cord injury (4 percent) [2].
Clinical evaluation — The patient's abdomen and chest should be examined for the presence of contusions or ecchymoses that might suggest that significant blunt forces have been sustained. Although diaphragmatic excursion depends upon variables such as body build, body posture, and lung volume, any bullet or stab wound between the level of the T4 and T12 dermatomes (figure 5) has the potential to cause diaphragmatic injury, particularly if penetrating wounds are found on both sides of the diaphragm. Penetrating wounds in the posterior or flank region of the trunk can also lead to diaphragmatic injury. (See 'Anatomy of the diaphragm' above.)
The presence of a rent in the diaphragm can lead to acute herniation of abdominal contents into the chest (image 1). The finding of diminished breath sounds may indicate collapse of the lung due to herniation. If the stomach has herniated, air injected into the nasogastric tube may be heard in the chest upon auscultation, although this finding is nonspecific. (See "Inpatient placement and management of nasogastric and nasoenteric tubes in adults", section on 'Confirmation of placement'.)
Delayed presentation — The trauma patient may initially have no symptoms or signs to suggest an injury to the diaphragm, or associated injuries may be sufficiently severe that definitive evaluation for diaphragmatic injury is delayed. With time, the diaphragmatic defect due to injury has a tendency to become larger, and herniation of abdominal organs becomes more likely, particularly if left sided. In one small series of delayed diagnosis of traumatic diaphragm rupture, 3 of 16 patients (19 percent) had their injuries missed at initial laparotomy [13]. The majority of these injuries (15 out of 16) were on the left [13]. Small right-sided injuries may remain stable because the liver tamponades the defect preventing bowel herniation.
Patients with previous thoracoabdominal trauma who present with abdominal pain and nausea/vomiting should be evaluated for a possible missed diaphragmatic injury as a cause of gastrointestinal obstruction due to herniation (image 2). Failure to diagnose and repair the diaphragm can lead to intestinal strangulation and, potentially, death.
DIAGNOSTIC EVALUATION — The mechanism of injury and physical exam findings may suggest the need for additional evaluation beyond initial imaging studies that are typically obtained during trauma evaluation. Specifically, trauma mechanisms that confer large amounts of force to the anterior abdomen in association with the auscultation of bowel sounds or nasogastric suction over the left thorax should prompt immediate inclusion of traumatic diaphragmatic injury among the possible injuries impacting the patient.
While a diagnosis of diaphragmatic injury is often coincidentally made while using computed tomography (CT) to rule out significant life-threatening injuries (eg, traumatic aortic rupture or visceral injuries) (algorithm 1) [14], small tears may not be seen even with sophisticated imaging techniques. Advanced imaging techniques appear promising. Nevertheless, when there is a high index of suspicion for diaphragmatic injury, but initial trauma imaging is inconclusive, we agree with guidelines from the Eastern Association for the Surgery of Trauma (EAST) that recommend diagnostic laparoscopy (or thoracoscopy) for detection of diaphragmatic injury in most trauma patients [15]. Both diaphragmatic leaflets are typically easily seen with laparoscopy, and the overall risk of the procedure is low. Thoracoscopy may be more appropriate for posterior right-sided diaphragmatic injuries. For patients with difficult laparoscopic access due to multiple previous laparotomies, advanced imaging techniques can be used to further evaluate the diaphragm.
Findings suggestive of diaphragm injury on initial imaging
Ultrasound — The Focused Assessment with Sonography in Trauma (FAST) examination is an important component of trauma management that is used primarily to detect free intraperitoneal blood following trauma, particularly in patients who are hemodynamically unstable. (See "Initial evaluation and management of blunt abdominal trauma in adults", section on 'Ultrasound'.)
Ultrasound techniques can also be used to evaluate the diaphragm, but the use of ultrasound to identify traumatic diaphragmatic rupture is not standardized, and a negative study cannot be used to exclude the diagnosis [16-18]. To perform the examination, a 5.0- to 7.5-MHz linear array transducer is placed transversely on the abdomen with the transducer directed posteriorly toward the diaphragm. The diaphragm appears as a hyperechoic (ie, white) line superior to the liver. The diaphragm is followed from right to left and its continuity evaluated.
Findings on ultrasound consistent with diaphragmatic injury include discontinuity of the diaphragm, herniation of the liver or bowel loops through a diaphragmatic defect, floating diaphragm, and nonvisualization of the diaphragm. Indirect findings include pleural effusion or subphrenic fluid collection.
Plain chest radiography — The chest radiograph is the most commonly obtained imaging study used for the evaluation of trauma patients. Diaphragmatic injury on chest radiograph can be as obvious as identifying the stomach or other abdominal organs in the chest (image 3) or suggested by subtle, but nonspecific, signs, including asymmetric elevation of the hemidiaphragm, pleural effusion, basilar atelectasis, mediastinal shift, lack of clarity of the hemidiaphragm, irregular diaphragm contour, or rib fractures. Specific signs include abnormal nasogastric tube positioning with its distal end (tip) projecting above the hemidiaphragm (image 4) and presence of gas-containing hollow viscera into the thoracic cavity.
The sensitivity of initial portable chest radiography is 27 to 68 percent for the left hemidiaphragm and 17 to 33 percent for the right [19].
Computed tomography — Following blunt thoracoabdominal trauma, computed tomography (CT) is often performed as part of the initial trauma evaluation or based upon findings of a chest radiograph. CT is most commonly used in hemodynamically stable patients as a means to rule out solid organ and hollow viscus injuries.
CT can detect diaphragm injury and is more useful for assessing the posterior lumbar elements of the diaphragm (crura and arcuate ligaments) compared with the anterior leaflets. Portions of the diaphragm may be obscured due to similarity in attenuation levels to adjacent structures (eg, liver, spleen) (algorithm 1). Several direct and indirect signs on CT imaging can help establish the diagnosis of traumatic diaphragmatic rupture [20]. These include:
●Direct signs:
•Discontinuous diaphragm sign – Discontinuity of the diaphragm with segmental loss on imaging (image 5 and image 6).
•Dangling diaphragm sign – A comma-shaped fragment of the diaphragm as it curls inward, as seen on coronal reformations.
●Indirect signs:
•Diaphragm thickening – Thickening of the diaphragm at the site of injury, with or without retraction of the edges.
•Organ herniation sign – Presence of an intra-abdominal organ within the thoracic cavity through a defect in the diaphragm (image 7).
•Dependent viscera sign – With diaphragm rupture on the right, the upper one-third of the liver may abut the posterior ribs, and with left-sided rupture, the stomach or bowel may abut the posterior ribs or lie posterior to the spleen. This sign is seen on axial and sagittal reformations.
•Collar sign – The presence of a focal, waist-like constriction of the herniating abdominal viscus at the level of the torn diaphragm (better identified with sagittal and coronal views). Two rare variants of the collar sign have been described for right-sided organ herniation.
•Hump sign – Presence of a rounded portion of the liver herniating through the diaphragm, forming a hump-shaped mass, seen on coronal or sagittal reformations.
•Band sign – Presence of a linear lucency across the liver, along the torn edges of the hemidiaphragm, seen on coronal or sagittal reformations.
•Contiguous injury on both sides of the diaphragm – The ability to track an injury on both sides of the diaphragm even in the absence of seeing discontinuation of the diaphragm.
These signs of traumatic diaphragm rupture were evaluated in a series of CT scans of the thorax in 23 patients with clinically proven diaphragmatic injuries [20]. The discontinuity sign was the most common radiologic finding present in 95.7 percent of studies. Nevertheless, discontinuity of the posterior diaphragm can be an anatomic variant seen in at least 11 percent of individuals [21]; however, in the context of recent trauma, this finding warrants further investigation. Diaphragmatic thickening was the next most common finding in approximately 70 percent of studies. Contiguous injury was the most commonly seen in penetrating trauma and was reported in 83 percent of studies. The dependent viscera and collar signs are highly specific but are predominantly seen in patients with blunt trauma due to smaller size of defect in penetrating injuries. Similarly, the dangling diaphragm and organ herniation signs were seen more commonly in patients with blunt trauma.
In the available studies, 4- or 16-slice CT scanners have a sensitivity of 82 to 87 percent and specificity of 72 to 99 percent for detecting diaphragm injury due to penetrating trauma [22,23]. However, first- and second-generation imaging studies were prone to missing centrally located radial tears. Some of the limitations of earlier scanners are being overcome with newer helical and multidetector (up to 256-slice) computed tomography (MDCT) studies, which are able to acquire volumetric data, eliminate motion artifact, and provide excellent three-dimensional reconstruction [24]. However, because of the rarity of diaphragmatic injury, the sensitivity and specificity for detecting diaphragmatic injury with advanced CT technology have yet to be firmly established. We expect the accuracy to be improved due to better longitudinal and in-plane image resolution. Even with higher-resolution scans, injuries can be missed in intubated patients on positive pressure ventilation because the abdominal organs that might have herniated into the chest are pushed back into the abdomen. Sagittal reconstructions may be helpful to define the injury in these patients. Where available, multidetector CT scanning is the primary diagnostic modality for identifying patients who require repair of a diaphragmatic injury. However, many hospitals, including some Level I trauma centers, may not have the benefit of these high-resolution scanners that may alter the management approach. (See 'Management approach' below.)
CT tractography has been used to evaluate hemodynamically stable patients with back or flank stab wounds to estimate wound depth [25,26]. CT tractography is performed by inserting sterile sponges soaked with 10% povidone iodine (eg, Betadine) or contrast (eg, Visipaque) into the stab wound. Patients then undergo helical abdominal CT scanning with only intravenous contrast. These scans are reviewed by both the attending radiologist and trauma surgeon. Studies have found that 100 percent of patients with negative CT scans can be successfully observed without finding of any new injuries [25]. These data are to be interpreted with caution, since outcomes may be impacted by the packing technique used and the overall size of the penetrating wound. It is unknown whether this diagnostic approach is superior to traditional CT scanning, but it may be better for determining the wound trajectory. Certainly, Visipaque that is identified in the intraperitoneal or retroperitoneal space in either initial or subsequent imaging confirms traumatic violation.
Magnetic resonance imaging — Magnetic resonance imaging (MRI) can be time consuming to perform and often places the patient in a hospital location that is remote from ready access and intervention. For this reason, MRI does not play a significant role in the initial evaluation of the injured patient. However, MRI may be applicable in a subset of hemodynamically stable patients who cannot undergo computed tomography (eg, allergic to IV contrast) or in those for whom a suspicion for diaphragmatic injury remains high in spite of other negative diagnostic studies (image 2) [27].
Diagnostic laparoscopy/thoracoscopy — If the index of suspicion is high for diaphragmatic injury, but initial trauma imaging studies are inconclusive, minimally invasive techniques (laparoscopy, thoracoscopy) can be used to confirm (or rule out) a diaphragmatic injury, and when identified, to potentially repair it with minimally invasive techniques (algorithm 1) [28-31]. Although there is the theoretical concern for pneumothorax with insufflation of the abdomen in patients with diaphragmatic injury, this has not been described in the literature. We prefer to prepare the chest along with the abdomen in the event that a chest tube is needed.
Laparoscopy has a sensitivity of 88 percent and a specificity approaching 100 percent in the diagnosis of diaphragmatic injury [28]. In one retrospective review of 119 patients with left-sided penetrating thoracoabdominal trauma, 31 percent of the patients found to have diaphragmatic injury on laparoscopy had no abdominal tenderness, and normal chest radiograph was seen in 40 percent [30]. One fourth of patients did not have sufficient clinical signs and/or radiology examination to diagnose the injury.
Thoracoscopy can also be used to diagnose diaphragmatic injury and is particularly useful for the diagnosis of posterior right-sided diaphragmatic injuries [15]. In a small series of 14 patients, all injuries of the diaphragm were detected with thoracoscopy [31].
Role of diagnostic peritoneal lavage — Diagnostic peritoneal lavage (DPL) was commonly used in the past but has been supplanted by the Focused Assessment with Sonography for Trauma (FAST) examination and other imaging modalities for the diagnosis of diaphragmatic injury. The interpretation of DPL is discussed elsewhere. (See "Initial evaluation and management of blunt abdominal trauma in adults", section on 'Diagnostic peritoneal lavage' and "Diagnostic peritoneal lavage (DPL) or aspiration (DPA)".)
DPL may still play a role in the evaluation of penetrating thoracoabdominal trauma [32]. To improve its sensitivity for diagnosing diaphragmatic injuries in penetrating thoracoabdominal trauma, many clinicians have modified the red blood count (RBC) criteria, accepting lower RBC counts (5000 to 10,000/mm3) to decrease the rate of false negative results [33].
Diagnostic dilemmas — Imaging studies may be falsely positive for diaphragmatic injury.
●On plain radiography – Eventration of the diaphragm and Chilaiditi's sign may be seen on chest radiography [34].
•Eventration of the diaphragm is due to thinning and elevation of the diaphragm in such a manner that pneumoperitoneum or herniation of bowel seems to be present above the diaphragm. Eventration of the diaphragm is thought to be due to a congenital defect of the diaphragm or an acquired defect from complete or incomplete paralysis of the diaphragm. Hypoplasia of the lung on the involved side may contribute to the etiology in the congenital variant. The acquired variant usually occurs on the right side. If suspected, previous imaging studies, if available, should be compared with images obtained at the time of trauma admission.
•Chilaiditi's sign can also lead to a false positive diagnosis of diaphragmatic injury [35]. Chilaiditi's sign is due to a loop of bowel interposed between the liver and the diaphragm. Although the involved bowel is usually transverse colon, it can also be distended small bowel. When associated with abdominal pain, this entity is known as Chilaiditi's syndrome.
●On chest CT – Congenital or acquired diaphragmatic defects, physiologic fenestrations, or hematoma tracking adjacent the diaphragm might be seen.
•Congenital or acquired diaphragmatic defects or hernias are usually small and there are no other associated imaging signs of trauma.
•Physiologic fenestrations or pores are more frequently seen in older patients, posteriorly at the crura.
•Thickening of the diaphragm can be due to hematoma tracking along the diaphragm and not necessarily related to diaphragmatic injury.
COMPLICATIONS OF DIAPHRAGMATIC INJURY — Overall morbidity associated with diaphragmatic injury ranges from 30 to 68 percent and is related to the presence of associated injuries [8,36,37]. Patients suffering blunt trauma have higher complication rates (60 percent) compared with those who have penetrating trauma (40 percent) [38].
Herniation — The true incidence of abdominal organ herniation due to diaphragmatic injury is unknown since many cases likely go undiagnosed. Herniation of the stomach, spleen, colon, small intestine, and omentum occur on the left and, on the right, the liver or colon. Cardiac herniation has also been reported.
Patients with prior thoracoabdominal trauma who present with signs and symptoms consistent with gastrointestinal obstruction or ischemia should be evaluated for a possible missed diaphragmatic injury. (See 'Delayed presentation' above.)
Diaphragm paralysis — The diaphragm is the major muscle of respiration, and during quiet breathing, its contraction is responsible for 75 to 80 percent of tidal volume. With unilateral paralysis of the diaphragm, the normal hemidiaphragm descends normally, while the paralyzed hemidiaphragm moves upward. The resultant mediastinal shift reduces lung capacity by as much as 20 to 30 percent. (See "Diagnostic evaluation of adults with bilateral diaphragm paralysis".)
Although phrenic nerve injury associated with trauma is more commonly seen with high cervical spine injuries or penetrating neck trauma, injury to the phrenic nerves can occur as a result of thoracoabdominal trauma and its management, such as during emergent thoracotomy or repair of injuries to mediastinal structures. Phrenic nerve injury can also be due to diaphragm tears [39]. Patients with traumatic diaphragm paralysis who require ventilator support beyond two weeks may be candidates for diaphragmatic plication.
Diaphragm plication fixes a paralyzed hemidiaphragm in the flat position, decreasing its paradoxical movement and improving the overall efficiency of mechanical ventilation without impairing the potential for the recovery of diaphragm function (figure 6). The treatment of diaphragm paralysis is discussed elsewhere. (See "Treatment of bilateral diaphragmatic paralysis in adults".)
Pulmonary complications — Diaphragmatic injury is often accompanied by rib fractures and pulmonary contusion. Pulmonary complications are common with atelectasis occurring in 11 to 68 percent of patients, pleural effusion in 10 to 23 percent, and empyema in 2 to 10 percent with diaphragmatic injury [8,36,37]. Diagnosis and management of these complications are discussed in individual topic reviews. (See "Inpatient management of traumatic rib fractures and flail chest in adults".)
Biliary fistula — Combined injury of the liver, diaphragm, and lung can lead to biliary-pleural or bronchobiliary fistula formation. Biliary drainage from the thoracostomy tube establishes the diagnosis of biliary-pleural fistula. Bronchobiliary fistula occurs due to penetrating mechanisms that traverse a bronchus and biliary radical. The presenting symptom may be bilioptysis (coughing up bile).
The management of these traumatic fistulae is similar to that of biliary fistulae from other causes. Patients who develop fever, chills, or leukocytosis should undergo computed tomography of the chest and abdomen to identify any pleural fluid collections that should be percutaneously drained and cultured. The presence of bile confirms the presence of a biliary-pleural fistula. A HIDA scan can also be used for the diagnosis. Endoscopic retrograde cholangiopancreatography (ERCP) defines the anatomy of the injury and potentially offers treatment with sphincterotomy and/or biliary stent placement. (See "Overview of endoscopic retrograde cholangiopancreatography (ERCP) in adults".)
MANAGEMENT APPROACH — Hemodynamically stable patients with a negative physical exam and imaging studies can be observed (algorithm 1). Patients undergoing exploratory laparotomy for trauma for other reasons should have a thorough inspection of the diaphragm as a part of the trauma laparotomy. (See 'Trauma laparotomy' below.)
All left-sided diaphragm injuries and some right-sided injuries require repair when recognized (algorithm 1). Acute injuries are usually repaired using an abdominal approach. The force needed to cause blunt diaphragmatic injury is significant, and although diaphragmatic injury can be isolated, it is more likely to be associated with other injuries that may need repair. Similarly, abdominal exploration is generally indicated for penetrating injuries. (See 'Associated injuries' above.)
For right-sided diaphragmatic injuries, the Eastern Association for the Surgery of Trauma (EAST) guidelines suggest initial nonoperative management, rather than operative repair in patients who are hemodynamically stable without signs of peritonitis [15]. Small asymptomatic right-sided injuries that are "tamponaded" by the liver have a low risk for significant long-term sequelae. Overall morbidity of operative repair is higher compared with the low likelihood of delayed herniation or missed intra-abdominal injury associated with right-sided diaphragmatic injury.
Some patients with severe associated injuries may require delayed management of the diaphragmatic injury (algorithm 1). (See "Overview of damage control surgery and resuscitation in patients sustaining severe injury".)
The timeframe over which an acute injury becomes chronic is subject to debate. Once the repair becomes elective and there is no longer a concern for concomitant injury, the possibility of minimally invasive repair from either an abdominal or thoracic approach increases [30,40]. Chronic diaphragmatic hernia is typically repaired with a thoracic approach.
SURGERY
Preparation — The patient (or the patient's next of kin if the patient is intubated or unresponsive) should be informed that although exploration is being performed to manage identified injuries, other intra-abdominal injuries may be discovered that need specific management. (See 'Associated injuries' above.)
Blood products should be available in the event the patient becomes hemodynamically unstable. A trauma transfusion protocol should be in place including packed red blood cells, Fresh Frozen Plasma (FFP) or similar products (eg, PF24), platelets, and possibly antifibrinolytics. (See "Initial management of moderate to severe hemorrhage in the adult trauma patient" and "Etiology and diagnosis of coagulopathy in trauma patients" and "Massive blood transfusion" and "Ongoing assessment, monitoring, and resuscitation of the severely injured patient", section on 'Management'.)
Prophylactic antibiotics are administered to prevent surgical site infection. For emergency trauma surgery, antibiotic selection is the same as for elective surgery with administration of a first-generation cephalosporin (eg, cefazolin). If there is concern for or confirmed enteric or colorectal contamination, anaerobic coverage with metronidazole is appropriate. In the event that there is excessive blood loss (>1.5 L) requiring transfusion of more than 6 units of packed red blood cell products, redosing prophylactic antibiotics is recommended. Prophylactic antibiotics should also be redosed if the procedure is greater than three hours for cefazolin or two hours for cefoxitin. However, the use of damage control surgery principles should make long initial trauma laparotomy times extremely rare. (See "Antimicrobial prophylaxis for prevention of surgical site infection in adults" and "Overview of damage control surgery and resuscitation in patients sustaining severe injury".)
Trauma laparotomy — A midline trauma laparotomy incision from the xiphoid to pubis is used to evaluate the abdomen and retroperitoneum and rule out or repair identified injuries. Control of hemorrhage and gastrointestinal spillage are the first priorities. For patients who are hemodynamically stable and have undergone imaging that demonstrates only a traumatic diaphragmatic rupture without fluid in the abdomen, an upper midline incision can be performed initially and extended, if necessary. (See "Overview of damage control surgery and resuscitation in patients sustaining severe injury", section on 'Damage control laparotomy'.)
The abdominal surface of the diaphragm should be included as part of a standard abdominal exploration. After ligation and division of the falciform ligament, the right hemidiaphragm is inspected by downward traction on the liver. The liver does not usually need to be mobilized away from its coronary ligamentous attachments. Downward traction on the fundus of the stomach and dome of the spleen allows visualization of the left hemidiaphragm. The central tendon, the esophageal hiatus, and the diaphragmatic crura at the aortic hiatus should also be inspected to ensure they remain firmly attached to the lumbar vertebrae and are not torn.
When herniation of abdominal organs is present, the organs should be gently reduced from the diaphragmatic defect back into the abdominal cavity. Although gentle traction is usually always a successful approach to reducing displaced abdominal contents, occasionally injury to the spleen may become more severe with downward traction. In this setting, carefully extending the hernia defect facilitates an easier reduction of organs back into the abdomen. With chronic herniation, there is always a hernia sac with adhesions. Dissection of the hernia sac away from the abdominal contents is first necessary; then the abdominal organs can be reduced without causing injury. Any serosal or capsular tears that occur are identified and repaired.
The edges of the diaphragmatic defect are grasped with Allis clamps. This allows for caudad retraction of the injured diaphragm for better exposure during the suture repair and to ensure the safety of thoracic soft tissue structures adjacent and superior to the suture repair. The thoracic cavity is inspected through the defect for contamination or ongoing hemorrhage. If contamination exists, copious lavage is performed. Irrigation of the thoracic cavity through a laparotomy approach has been shown to be effective in controlling biliary, gastric, or enteric contamination in patients with penetrating trauma [41].
Any devitalized diaphragmatic tissue is debrided. The diaphragm is repaired with permanent suture or absorbable monofilament suture (Size 0, 1) in a running or interrupted fashion. The author prefers to use permanent monofilament suture. Gentle downward traction of the cardiac surface of the diaphragm away from the heart during the placement of sutures will avoid inadvertent cardiac injury. In rare cases of massive diaphragmatic and chest wall destruction, other surgical options are available (eg, diaphragm transposition) [42].
The diaphragm has an excellent blood supply (figure 2), and breakdown of repairs is generally uncommon. One cause of breakdown of the repair is failure to take significant bites of tissue during the repair. Infection can also contribute to breakdown of the repair. Antibiotics should be given prophylactically prior to surgery and are continued postoperatively if indicated for other reasons. (See 'Preparation' above.)
Minimally invasive approach
Laparoscopic surgery — For the patient with a diagnosed diaphragmatic injury in whom there is no concern for other abdominal injuries, minimally invasive (typically laparoscopic) management of these injuries is preferred [15]. When diaphragmatic injury is identified on laparoscopy or thoracoscopy, it may be amenable to repair using minimally invasive techniques, but if not, conversion to open surgery may be necessary. An open operative approach is acceptable and preferred for surgeons who would be more effective using a laparotomy. For patients with prior abdominal incisions in whom there is concern for adhesions in the midline, the alternative entry site in the left upper quadrant 3 cm below the costal margin (ie, Palmer's point) may not be as safe when there is left-sided trauma diaphragmatic hernia present. (See 'Surgery' above and "Abdominal access techniques used in laparoscopic surgery", section on 'Lateral abdomen/flank'.)
A Trauma Quality Improvement Program nationwide propensity-matched study comparing laparoscopic with open repair approaches for traumatic diaphragmatic injuries demonstrated that minimally invasive approaches had overall decreased morbidity and low conversion rates [43]. A retrospective review from South Africa demonstrated the feasibility of a minimally invasive approach. Among 45 hemodynamically stable patients with penetrating thoracoabdominal trauma, the overall success rate for the laparoscopic approach to diaphragmatic repair was 93 percent. Twenty-two patients had Grade 3 or 4 diaphragmatic injuries. The authors concluded that high injury severity score is not a contraindication to a laparoscopic approach, provided the patient remains hemodynamically stable. Patients who require a damage control approach should not be managed using a minimally invasive approach for diaphragmatic injuries.
Robotic surgery — A few case reports have been published detailing robotic diaphragmatic repair in trauma patients [44]. The principles that govern this minimally invasive approach are identical to those in laparoscopy. The patient should be hemodynamically stable, and the surgeon should be experienced in caring for associated injuries using the robotic approach or convert to an open approach, when needed. The practicality of deploying a robotic approach in the evening or at night has not been studied. However, there will be trauma patients with delayed diagnosis of diaphragmatic hernia in the initial or later hospitalizations. For this small cohort of patients, a robotic approach may be advantageous, particularly if there is a hostile abdomen and a thoracic approach is planned. In this circumstance, this has superior ergonomics for the surgeon, but is more costly. (See "Overview of minimally invasive thoracic surgery", section on 'VATS versus RATS'.)
Use of mesh — When there is no need for extensive debridement and there has been little diaphragmatic tissue destruction, more than enough diaphragmatic tissue should be available for a primary repair without the need for mesh material. In the rare instance that primary repair is not possible due to excess diaphragmatic tissue loss or chronic expansion of the defect (Grade IV or V injury), nonabsorbable prosthetic materials (eg, polytetrafluoroethylene, polyethylene) can be used, provided no colonic contamination is present. When contamination is present, the abdomen is copiously irrigated and an autologous tissue flap (eg, omentum, latissimus dorsi flap) or a bioprosthesis should be used [45].
Managing cardiac herniation — Acute cardiac herniation is usually due to high-speed motor vehicle collision [46]. The heart herniates inferiorly into the peritoneal cavity due to disruption of the central tendon. The diagnosis is established with chest radiograph or FAST examination. Repair of this injury is through a laparotomy incision.
MORTALITY — The mortality for diaphragmatic injury depends upon the trauma mechanism and presence of associated injuries. The National Trauma Data Bank (NTDB) reports an overall mortality of 25 percent for patients with diaphragmatic injury. The immediate 24-hour mortality from diaphragmatic injuries is due to associated injuries. Mortality is higher with blunt compared with penetrating injury due to the presence of significant associated thoracic or abdominal injuries [4,9]. In the NTDB study, patients with blunt diaphragmatic injury had a significantly higher mortality rate (19.8 versus 8.8 percent) [4]. Significantly more patients with blunt injury had pulmonary complications (14.8 versus 6.6 percent) and acute respiratory distress (7.4 versus 4.1 percent) compared with penetrating injuries.
Poor physiologic status upon presentation of the patient accompanied by continued hemorrhage is a predictor of death [9]. The mortality for delayed presentation of diaphragmatic injury for the patient with incarceration of gastrointestinal contents is approximately 20 percent, increasing to 40 to 57 percent when bowel strangulation is present [47].
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Thoracic trauma".)
SUMMARY AND RECOMMENDATIONS
●The diaphragm and diaphragmatic injury – The diaphragm is the musculotendinous boundary between the thoracic cavity and abdominal cavity and plays an important role in normal respiratory function. Diaphragmatic injury is uncommon, representing less than 1 percent of all traumatic injuries. A high index of suspicion for this injury is needed because delayed diagnosis is associated with an increased risk for herniation and strangulation of abdominal organs, which can be life-threatening. (See 'Anatomy of the diaphragm' above and 'Recognition of diaphragmatic injury' above.)
●Mechanisms of diaphragm injury – A suspicion for diaphragmatic injury begins with the identification of the injury mechanism, physical examination, and assessment of associated injuries. Direct injury to the diaphragm is due to an implement or missile passing through the diaphragm. Indirect injury is caused by a sudden increase in intra-abdominal pressure that is sufficient to overcome the strength of the diaphragmatic tissues. As such, penetrating injury leads to smaller rents that are more likely to be missed compared with blunt rupture, which typically causes large radial tears (See 'Recognition of diaphragmatic injury' above.)
●Associated injuries – The diaphragm is usually injured in association with other thoracic and abdominal organs. Blunt traumatic injuries that are highly associated (>30 percent) with diaphragmatic injury include hemothorax, liver injury, and splenic injury. Any penetrating mechanism found to involve organs on either side of the diaphragm is likely to be associated with a diaphragmatic injury. (See 'Associated injuries' above.)
●Diagnostic evaluation – The mechanism of injury and physical exam findings may suggest the need for additional studies beyond plain chest radiograph. Computed tomography (CT) is the primary imaging modality used to diagnose diaphragmatic injury. Features consistent with diaphragmatic injury on CT scan are listed above. Alternative modalities include ultrasound or magnetic resonance imaging (MRI). Small tears, particularly right-sided penetrating injuries, may not be identified by any imaging modality. (See 'Diagnostic evaluation' above.)
●Management
•Hemodynamically stable patients with a negative physical exam and imaging studies can be observed (algorithm 1). Small right-sided diaphragmatic injuries in hemodynamically stable patients can be managed expectantly. Patients who are being observed should be monitored for signs or symptoms that suggest herniation. (See 'Management approach' above.)
•Laparoscopic or thoracoscopic exploration (with or without robotic assistance) may be needed to obtain a diagnosis (and an opportunity for repair) for those in whom a high index of suspicion for diaphragmatic injury persists despite negative imaging studies.
•All left-sided diaphragmatic injuries and most right-sided injuries should be repaired when recognized (algorithm 1). Acute injuries of the diaphragm are repaired from the abdomen, often in conjunction with abdominal exploration to identify and repair other associated injuries. The diaphragm is repaired primarily unless a large defect is present, in which case prosthetic materials are used provided there is no colonic contamination. (See 'Surgery' above.)
●Mortality and complications – The overall mortality associated with diaphragmatic injury is 25 percent, primarily due to the presence of life-threatening chest or abdominal injury but can also result from complications of the injury itself. Complications of diaphragmatic injury include gastrointestinal herniation, pulmonary sequelae due to altered respiratory mechanics, diaphragm paralysis, and pleural fistula. Of these complications, gastrointestinal herniation contributes to mortality the most due to bowel ischemia and infarction. (See 'Mortality' above and 'Complications of diaphragmatic injury' above.)
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