Chapter 28: Diaphragm

The diaphragm, the most important muscle of respiration, separates the thorax and the abdomen. It can be injured in isolation or involved with injury in either body cavity, and the most challenging concern is the identification of injury. Initially the injury may be asymptomatic with later development of herniation and strangulation of the stomach or other viscera.

Traumatic diaphragmatic rupture was first reported by Sennertus in 1541, and Ambroise Paré was the first to report a series of diaphragmatic perforations found at autopsy.¹ Paré also described gastric and colonic incarceration in a ruptured diaphragm and the consequences.² The diagnosis was made in an antemortem fashion for the first time by Bowditch in 1853,³ and it was not until 1886 that Riolfi was credited with the first successful repair.⁴ The first acute repair by Walker in 1899 was in a patient who had been struck by a falling tree.⁵ The largest early review of 378 diaphragmatic hernias was by Hedblom in 1925.⁴

The diaphragm is a dome-shaped musculofibrous septum separating the abdomen and thorax. It is bounded above by both pleural spaces and the pericardium, which is attached to the central tendon. Structures immediately adjacent to the inferior side of the diaphragm include the liver, spleen, stomach, and to varying degrees the colon, omentum, and small bowel. The origin of the diaphragm includes the lower sternum, lower six costal cartilages and adjacent ribs, and medial and lateral lumbocostal arches. The crura, two tendinous pillars, arise from the lumbar vertebrae. The insertion of the diaphragm is into the central tendon, an aponeurosis, located at the top of the dome, oriented transversely, and separated into three segments. At rest the diaphragm rises to the level of the fourth intercostal space on the right and the fifth intercostal space on the left. At maximal contraction the diaphragm descends two rib spaces bilaterally. The aorta passes behind the diaphragm and between the crura where it has no attachments. Along with the aorta the thoracic duct and azygous vein pass through this opening. The esophagus traverses the esophageal hiatus mostly composed of the right crus along with the vagus nerves. The inferior vena cava passes through its hiatus at the junction of the right and middle leaflets of the central tendon to which it may be adherent (Fig. 28-1).

The blood supply to the diaphragm is multiply redundant making necrosis extremely rare.⁶ The major source of blood supply to the abdominal side of the diaphragm is the inferior phrenic arteries, which are branches of the abdominal aorta or celiac trunk. Additional blood supply is from the superior phrenic, pericardiophrenic, musculophrenic, and the intercostal arteries. Lymphatic drainage is rich on both sides of the diaphragm with the peritoneal surface the major contributor to peritoneal lymphatic drainage. Innervation is principally through the phrenic nerves with some contribution of the sixth or seventh intercostal nerves to the costal region of the diaphragm. Both phrenic nerves enter the diaphragm near the anterior border of the central tendon. These nerves give branches along the thoracic surface of the diaphragm before penetrating it to spread branches in anterior, posterior, and lateral directions. The nerves are often buried deep in the muscle, and one should not rely on visualizing the nerves in order to choose incisions in the diaphragm. Safe diaphragm incisions that protect the phrenic nerves are depicted in Fig. 28-2.

The diaphragm is a vital muscle involved in the function of both the digestive and respiratory systems. It participates in breathing, swallowing, coughing, defecation, emesis, micturition, parturition, sneezing, and vocalization.⁷ In humans it is the most important muscle of inspiration and can independently generate negative intrapleural pressure sufficient for respiration.⁸ The innervation of the diaphragm is centrally unified in the spinal cord, and the entire diaphragm from the crura to the lateral margins has motor neuron origins intermingled within the spinal cord.⁹ The crural components, however, may have their function overridden through peripheral or central mechanisms related to function of the gastrointestinal tract.

Perforation of the diaphragm can lead to acute changes in physiology. The displacement of abdominal viscera into the chest due to the pressure gradient between the abdomen and the chest may compromise both cardiac and respiratory function. Cardiac dysfunction due to reduced ventricular filling can lead to decreased cardiac output. Significant compression of the pulmonary parenchyma can lead to impaired ventilation on the ipsilateral side, and, if more severe, mediastinal shift and compression of the contralateral lung. As with any herniation of portions of the gastrointestinal tract, sequelae such as ischemia, necrosis, and perforation may develop. Unfortunately, there are no long-term outcome data that describe diaphragmatic function after repair for trauma. There are many reports of delayed repairs of diaphragmatic injuries, and this suggests that repair is durable and has little impact on either pulmonary or gastrointestinal tract function.

The reported incidence of injuries to the diaphragm after blunt trauma ranges from less than 1 to 7% and from 10 to 15% in victims of penetrating trauma.^10,11,12 This wide range stems from an inability to identify injuries treated at nontrauma centers, death prior to hospital admission, and missed injuries after admission to a trauma center despite complete evaluation. A query of the National Trauma Data Bank (NTDB) for the years 2002–2007 demonstrated an incidence of 0.43% or 10,128 injuries among 2,349,554 patients (Table 28-1).¹² In a study at one center that included data from the medical examiner, survival to hospital admission was 87% indicating a relatively small fraction of patients are missed due to death.¹³ The highest rate of injury occurs in patients sustaining penetrating trauma to the thoracoabdominal region where the incidence of diaphragm injury has been reported to range as high as 42%.¹⁴ In one study of asymptomatic patients with penetrating thoracoabdominal trauma an injury rate of 24% was documented when mandatory laparoscopy was performed.¹⁵

Most traumatic diaphragmatic hernias occur on the left side.¹⁰ In the past, a congenital weakness in the left hemidiaphragm was thought to predispose to injury.¹¹ It is more likely, however, that the liver affords some protection to the right hemidiaphragm by mitigating the effects of blunt kinetic energy applied to the abdomen.¹⁶ The kinetic injury needed to create a right-sided diaphragmatic injury is greater than that needed to create a left-sided injury.¹⁷ Similarly, penetrating injury to the diaphragm has a left-sided predilection secondary to the prevalence of right-handed assailants.^18,19 Recent data, however, suggest that right-sided injuries may be more frequent than previously noted. In 2013, Zarour et al reviewed 773 patients with diaphragmatic injury and noted that 57% of injuries were on the left, 40% on the right and 3% were bilateral.²⁰ Penetrating wounds typically result in a smaller injury, but these injuries may enlarge over time and eventually cause acute incarceration and/or strangulation of abdominal viscera.^18,19,20,21

Grimes classified diaphragmatic injuries into the following three phases of presentation: acute, or during the period of recovery from injury; latent, an asymptomatic period; and obstructive, during which time herniation leads to cardiovascular compromise or gastrointestinal obstruction or perforation.²² Presentation in the acute phase is often dominated by symptoms from concomitant injuries. Patients may have minimal signs of external injury or be experiencing severe shock and respiratory compromise that may or may not be directly related to the diaphragmatic injury. In the less severely injured, possible signs and symptoms include shoulder pain, epigastric pain, vomiting, dyspnea, absent breath sounds, or bowel sounds heard during auscultation of the chest.²³ It is likely that the advent of routine helical computed tomography (CT) scanning has decreased the incidence of missed diaphragmatic injuries after blunt trauma.²⁴ While the majority of injuries are diagnosed acutely, case series have reported 3–15% of cases presenting in the late or obstructive phase.^25,28

In the latent phase visceral herniation is asymptomatic and may be discovered as an incidental finding on radiographic studies performed for other reasons. Patients presenting in the obstructive phase often experience nausea, vomiting, early satiety, pain, dyspnea, postprandial pain, or generalized chest and abdominal pain. Patients may also present in extremis with signs and symptoms of septic shock due to ischemia or perforation related to strangulation or gangrene of incarcerated viscera or with cardiovascular collapse due to compression.^21,26

Blunt diaphragmatic injury typically involves high-energy compression-type mechanisms, and associated injuries are common. Traumatic brain injury is present in half of the patients and is predictive of mortality.²³ Other associated injuries include pelvic fractures, long bone fractures, and rib fractures. Intrathoracic injuries include pneumothorax, pulmonary contusion, lung lacerations, blunt myocardial injury, and aortic rupture.^16,23,27 Solid organ injuries are the most common associated intra-abdominal injuries.^16,27,28

Penetrating injuries also have high rates of associated injuries, especially to intra-abdominal viscera, but include hemothorax and pneumothorax as well. Specific intra-abdominal organs typically injured with penetrating diaphragmatic injury include the upper abdominal organs.^14,19,23,28 A list of associated injuries identified in patients with an injury to the diaphragm in the National Trauma Data Bank (NTDB) is presented in Table 28-2.

Diaphragmatic rupture is often asymptomatic, or the presentation is dominated by other injuries making an immediate diagnosis difficult. Information about the mechanism of injury should be obtained from prehospital personnel. In patients involved in motor vehicle crashes, information about the velocity and direction of impact, the severity of vehicular damage, the presence of passenger-compartment intrusion, and the presence or absence of deformity of the steering wheel will be helpful to indicate the severity of the crash. Injuries are graded according to the American Association for the Surgery of Trauma-Organ Injury Scale for Diaphragmatic Injuries (Table 28-3).²⁹

In penetrating trauma any injury to the thoracoabdominal area should raise suspicion for a potential diaphragmatic injury. Although most stab wounds that result in diaphragmatic injury will be in this region, gunshot wounds that injure the diaphragm may occur anywhere on the trunk.²⁶

The initial diagnostic study for any patient where there is suspicion for injury to the diaphragm is a plain chest x-ray. Sensitivity of a chest x-ray for diaphragmatic injury has been reported to be in the range of 27–62% for left-sided injuries and 18–33% for right-sided injuries.³⁰ The finding pathognomonic for blunt and some penetrating injuries of the hemidiaphragm is visualization of a hollow viscus above it with or without an area of constriction at the level of the diaphragm. Identification of the stomach above the diaphragm is often facilitated by the abnormal position of a nasogastric or orogastric tube (Fig. 28-3). Loss of a smooth, diaphragmatic contour, ipsilateral pleural effusion, ipsilateral elevated hemidiaphragm, and mediastinal shift represent nonspecific findings associated with diaphragmatic herniation. Contrast swallow studies and enemas as well as fluoroscopy have been used in the past and are potentially helpful (Fig. 28-4); however, their use has been largely supplanted by cross-sectional imaging techniques.

Helical CT for the detection of blunt diaphragmatic disruption has a reported sensitivity of 71–100% and specificity of 75–100%, and sensitivity improves to 78–100% if only left-sided injuries are included.³¹ Multidetector CT (MDCT) scans with multiplanar reformatted images may improve diagnostic accuracy, though no large studies evaluating accuracy have been published. Findings consistent with diaphragmatic disruption include the following: direct visualization of the defect; segmental nonvisualization of the diaphragm; herniation of viscera; constriction of a herniated viscus or a “collar sign” (Fig. 28-5); dependent viscera sign or contact of intra-abdominal organs with the posterior chest wall; thickening of the diaphragm; and active extravasation of contrast at the level of the diaphragm. MDCT has been evaluated in patients with penetrating trauma with a reported sensitivity and specificity of 87% and 72%, respectively, in one study.³² In addition to the signs above, contiguous visceral injuries on both sides of the diaphragm are an important potential finding in penetrating trauma.

A recent study from Montreal questioned the efficacy of imaging modalities in the identification of traumatic diaphragmatic injury. They evaluated 105 patients over 13 years and noted that laparotomy for associated injury was the most common mechanism (57%) by which diaphragmatic injury was identified. A chest x-ray as read by an attending radiologist identified an additional 44% of injuries, although only 10% of these injuries were identified by the trauma team. Cross sectional imaging with CT identified the remaining 11% of injuries.²⁸

Magnetic resonance imaging (MRI) provides excellent resolution of the diaphragm and separates it from surrounding structures including the liver and atelectatic lung.³¹ In general, a distinct defect in the diaphragm can be visualized on MRI in addition to the other signs typically found on a CT scan (Fig. 28-6). MRI is limited in application due to issues with the time required, location of scanners in most institutions, and poor access to the patient during the study. In the hemodynamically normal patient with equivocal CT findings, MRI may have a role, though there have not been any large studies examining its accuracy to date.

Ultrasound has been reported in two case series to be capable of providing the diagnosis of diaphragmatic rupture after blunt abdominal trauma.^33,34 Findings on ultrasound consistent with diaphragmatic rupture have included identification of viscera within the chest, visualization of the edge of the disruption, inability to visualize the diaphragm, and lack of diaphragmatic excursion in a spontaneously breathing patient. In patients with right-sided ruptures, a finding of liver sliding against the chest wall has also been reported.³⁵

Using the best noninvasive methods available, a preoperative diagnosis can be obtained only approximately 70% of the time.³⁶ Although thoracoscopy and laparoscopy are invasive, they have been used as diagnostic modalities after penetrating thoracoabdominal injuries that may have injured the diaphragm.^14,15,20 As the sensitivity of CT scanning improves, the need for thoracoscopy and laparoscopy may decline; however, none of the studies has compared the accuracy of CT scanning to that of laparoscopy.^14,15,20

Recently, a significant body of literature has evaluated both laparoscopy and thoracoscopy in the management of patients with traumatic injuries. Laparoscopy in select hemodynamically normal patients can decrease nontherapeutic laparotomy rates and reduce hospital costs, with a low rate of missed injuries.³⁷ In one study 36% of patients with a penetrating thoracoabdominal injury and a normal chest x-ray were documented to have a diaphragmatic injury.¹⁴ Due to the high rate of associated intra-abdominal injuries, finding a penetrating diaphragmatic injury on laparoscopy mandates laparotomy unless the surgeon has the laparoscopic skills to comfortably exclude and treat an intra-abdominal injury. Video-assisted thoracoscopic surgery is most commonly used for the evaluation of the diaphragm at the time of evacuation of retained hemothorax and/or empyema.³⁷ A potential diagnostic algorithm for identifying diaphragmatic injury is presented in Fig. 28-7.

The two principles of repairing acute diaphragmatic hernias are complete reduction of the herniated organs back into the abdominal cavity and watertight closure of the defect to prevent recurrence. Given the high rate of associated abdominal injuries (generally 1.6 intra-abdominal injuries per patient on average), repair of the acutely injured diaphragm is best performed via an exploratory laparotomy.^28,38,39 The right hemidiaphragm is best inspected after transection of the falciform ligament and downward traction of the liver. The left hemidiaphragm can be inspected by applying gentle downward retraction of the spleen and greater curvature of the stomach. The central tendon of the diaphragm should also be examined, along with the esophageal hiatus. Reduction of the intra-abdominal contents is generally not difficult in the period immediately following injury. If the herniated contents are difficult to reduce, the phrenotomy can be partially extended to facilitate reduction, with care taken to avoid injury to the phrenic nerve.

It may be necessary to carefully debride the edges of a laceration if devitalized tissue is found, as with a high-velocity missile or close-range shotgun wound. The edges of the diaphragmatic laceration should then be grasped with Allis clamps, and the laceration spread apart to inspect the ipsilateral pleural cavity. This allows for evaluation of ongoing hemorrhage from within the thoracic cavity, as well as the determination of the degree of contamination between the abdominal and thoracic cavities. Small diaphragmatic disruptions, commonly seen after penetrating trauma, can generally be repaired using interrupted nonabsorbable sutures. Larger defects, more likely associated with blunt trauma, may be repaired in a number of different ways, including interrupted figure of eight or horizontal mattress sutures, a running hemostatic suture line, or a double layer repair, using a combination of the two methods (Fig. 28-8). Generally, a no. 0- or 1-monofilament or braided nonabsorbable suture is used. The authors prefer a no. 1-nonabsorbable monofilament placed in an interrupted fashion for the repair of traumatic diaphragmatic defects. In patients in whom a laceration through the central tendon exposes the inferior aspect of the heart, meticulous attention is given to the placement of the sutures to prevent inadvertent puncture or laceration of the myocardium. At the completion of the repair, the integrity of the suture line may be tested by increasing intrathoracic pressure with the administration of large tidal volumes and assessment of diaphragmatic motion. This maneuver is repeated with the field flooded with sterile saline to determine if there is escape of air through the suture line.

In cases where there is concomitant injury to a hollow viscus in the abdomen, contamination of the chest will have occurred due to the pressure gradient between the positive pressure in the abdomen and the negative pressure in the thoracic cavity. In this event, careful irrigation of the thoracic cavity through the diaphragmatic disruption is necessary prior to diaphragmatic repair, as empyema is three times more prevalent when there is an associated injury to the bowel.^28,40 Zellweger et al⁴¹ studied the management of patients with penetrating thoracoabdominal wounds that injured the diaphragm and gastrointestinal tract and/or liver. He demonstrated that a transdiaphragmatic washout of the pleural cavity was an effective strategy to decrease thoracic contamination.⁴¹

Laparoscopic repair of diaphragmatic injuries is feasible. A diaphragmatic injury diagnosed by laparoscopy in the absence of other injuries mandating laparotomy or thoracotomy can be repaired with this approach.³⁶ Laparoscopic repairs of diaphragmatic injuries can be performed with sutures or staples.^14,15 The decision to proceed laparoscopically should be solely dependent on the skill of the operating surgeon. For laparoscopic explorations to rule out a left-sided diaphragmatic injury where diaphragmatic repair is contemplated, also, port placement is important. The initial port should be at the level of the umbilicus or just above depending on the patient’s body habitus. A sub-xiphoid port is placed for retraction of the liver, and a port is placed laterally on the left side just below the costal margin. This port is utilized to maintain traction on the stomach or other cranially herniated abdominal organs. The umbilical port is utilized for the 30° laparoscopic camera. Two additional ports in the bilateral mid-clavicular lines are used as working ports. These two ports are also placed in a subcostal location. After placing the patient in steep reverse Trendelenburg position and careful reduction of the abdominal contents back into the abdomen, the defect is repaired. Techniques of repair are identical to the open methods. For right-sided injuries, port placement is similar, moving the left lateral subcostal port to the right. The right lobe of the liver is retracted medially or caudally. The falciform ligament and the right triangular ligament may require division for adequate retraction and exposure of the injury.

At times, a thoracotomy is required for the management of a massive hemothorax, defined as greater that 1500 cc of blood on insertion of a chest tube or in the first 15–30 minutes or more than 200 cc of blood per hour for the first 4 hours after trauma.⁴² A laceration of the right hemidiaphragm with an associated laceration of the liver may present as a massive hemothorax, with the diagnosis made at the time of thoracotomy. In this scenario, the diaphragm may be repaired through the chest, but a formal laparotomy will be necessary for the operative management of the hepatic injury and to rule out other associated intra-abdominal injuries.

For thoracoscopic management of a known diaphragmatic injury, the patient is placed in the lateral decubitus position with the arm abducted to allow maximal superior displacement of the scapula. The initial 2 cm incision should be placed just below the tip of the scapula. Two further incisions are then placed to complete a triangle based on the patient’s intrathoracic anatomy. The principles of visceral reduction and the technique of repair remain similar to those used in open surgery.

Disruption of the diaphragm following high energy crushing injuries or major deceleration can result in avulsion of the diaphragm from its attachments to the chest wall. Repair of this injury may require an ipsilateral thoracotomy, which allows horizontal mattress sutures to be placed around the ribs and secures the diaphragm into its normal anatomic position. In the presence of a flail segment of the ipsilateral chest wall, formal fixation of the ribs may be required to facilitate this complex repair of the diaphragm.²³ Prosthetic material for diaphragmatic reconstruction in the acute setting is rarely indicated, as tissue retraction and loss has not occurred and concomitant gastrointestinal injuries may lead to an increased rate of postoperative infection.

Massive diaphragmatic destruction such as that caused by thoracoabdominal shotgun injuries merits special mention. Bender and Lucas⁴³ described the immediate reconstruction of the chest wall following this type of injury by first detaching the affected hemidiaphragm anteriorly, laterally, and posteriorly. The diaphragm was then translocated to a position above the full-thickness chest wall defect, which converted the defect functionally into an abdominal wall defect. This is performed by suturing the ribs at a higher intercostal space, while the abdominal wall defect was managed with local wound care in anticipation of reconstruction with either split-thickness skin grafts or myocutaneous flaps at a later date.⁴³

Patients who initially sustain small, undetected, diaphragmatic lacerations may remain asymptomatic or may experience a progressive increase in visceral herniation of the omentum or all or a portion of a hollow viscus.^44,45 The diaphragm as a muscle is quick to retract and atrophies. Therefore, tissue that could be approximated easily on the day of injury retracts in the latent or obstructive phase to the point where approximation is impossible at a late reoperation.

Chronic diaphragmatic hernias can be repaired either transabdominally or transthoracically, with the choice generally determined by the subspecialization of the surgeon.^46,47 The classical teaching, however, is that large chronic posttraumatic diaphragmatic hernias be approached using a thoracotomy to allow for lysis of intrathoracic adhesions. On occasion, a combined approach may be indicated to complete the procedure safely and effectively. The transthoracic approach offers several benefits including the direct visualization of intrathoracic adhesions, which may extend all the way to the apex of the pleural cavity, and avoidance of abdominal adhesions from the prior trauma.^48,49,50,51 The thoracic approach has been performed successfully using both open and thoracoscopic techniques.^52,53,54 The open procedure is generally performed through the seventh or eighth intercostal space using a posterolateral approach. On rare occasions, an extension along the costal arch into a thoracoabdominal incision may be needed to allow access to the abdominal cavity.

As noted above, the transabdominal approach is often considered less attractive, due to the inherent difficulty of visualizing adhesions to the lung and other intrathoracic structures, and dealing with potential dense intra-abdominal adhesions from prior trauma and/or surgery. Additionally, if the procedure cannot be completed at laparotomy, the incision will need to be closed and the patient repositioned for a posterolateral thoracotomy. This is because it is difficult to visualize the posterior diaphragm from an anterolateral approach. Laparoscopy has been described for the reduction of chronic diaphragmatic hernias, as well, although problems with the iatrogenic pneumothorax have mandated the insertion of a thoracostomy tube.^{50,55,56,57,58} No matter which approach is used, current recommendations support the role of open surgery for patients with defects greater than 10 cm and for those whose hernia extends to or through the esophageal hiatus.⁵⁵

Careful dissection is required to free the entire diaphragm from its adhesions to surrounding tissues. Once mobilized, the edges should be brought together to evaluate for tension. If the edges can be approximated easily, the repair should be performed primarily as described in the section on acute diaphragmatic injuries. Generally, defects up to 8 cm can be closed primarily.⁵⁹ Primary repair of larger defects in the diaphragm will cause unacceptable flattening of the diaphragm, and prosthetic material will be needed to reconstruct the diaphragm. Many different prostheses have been used, including mersilene, polytetrafluoroethylene (PTFE), polypropylene, and polydioxanone meshes.^{49,55,60,61,62,63} Recently, a 2-mm thick PTFE patch has been advocated as an excellent material for reconstructing the diaphragm as it provides the necessary strength and is watertight.⁵⁹ Generally, the patch is sutured using a running 0-nonabsorbable suture around the edges of the defect, often starting medially (Fig. 28-9). The patch must be tailored to minimize laxity in the diaphragm. Full-thickness bites in the diaphragm are necessary, with care taken to avoid injury to underlying structures. Other alternatives to synthetic mesh include a bovine pericardial patch, which in case series has proven to be an effective alternative to prosthetic materials.⁶⁴

For injuries extending laterally to the chest wall without adequate tissue for fixation, the prosthetic can be secured with interrupted sutures placed around the ribs, following the natural course of the native diaphragm. Medially, the mesh can be secured either to pericardium or to the posterior crus if inadequate native diaphragmatic tissue exists.⁵⁹ In contaminated fields, autologous tissue may be used instead of PTFE to reconstruct large diaphragmatic defects. Latissimus dorsi, rectus abdominis, external oblique, and transversus abdominis flaps have been described, mainly in pediatric populations.^{65,66,67,68,69} The benefit of autologous tissue in the pediatric population is that it allows for growth of the child. A surgical algorithm to approach diaphragmatic injuries is presented in Fig. 28-10.

Mortality following diaphragmatic injury is dependent on the severity of the associated injuries.²⁸ Mortality rates vary between 18 and 40%, depending on mechanism of injury (blunt vs penetrating).^28,36 Recurrence rates of diaphragmatic hernias following repair are difficult to ascertain; however, it appears that the recurrence rate is higher when absorbable suture is used for the initial repair.²⁸

Postoperative morbidity directly related to the acute surgical repair includes suture line dehiscence or failure of the diaphragmatic repair, paralysis of the hemidiaphragm secondary to an iatrogenic injury to the phrenic nerve, respiratory insufficiency, empyema, and subphrenic abscess. The complication rate after repair of a diaphragmatic injury has ranged from 30 to 68%.^70,71 Atelectasis has been documented in 11–68% of patients, with pneumonia and pleural effusions reported in another 10–23%. Sepsis, multiorgan system failure, hepatic abscess, and empyema have been reported in 2–10% of patients.^70,71

When complication rates were compared in blunt versus penetrating injuries of the diaphragm in one review, patients with blunt trauma had a 60% complication rate versus 40% complication rate in those with penetrating trauma.⁷² Most of the morbidity reported in these studies is clearly the result of the large number of associated injuries present in association with diaphragmatic injuries.^70,72 Mortality following repair of a chronic diaphragmatic hernia depends entirely on the presence or absence of obstructive symptoms at the time of presentation. A mortality of less than 10% is expected in patients with asymptomatic diaphragmatic hernias, and this is related to the patient’s comorbidities and not to the repair.^26,73 Patients presenting with gastrointestinal obstruction have a significantly higher morbidity (>60%) and mortality (25–80%). This reinforces the need to pursue the diagnosis and surgical management of diaphragmatic injuries prior to the onset of obstructive symptoms with chronic hernias.^19,26,37

Blunt ruptures of the central tendon of the diaphragm involving the pericardium are rare and may present as acute injuries or as chronic hernias following missed injuries. Most are caused by combined blunt trauma to the chest and abdomen; however, isolated trauma to either one of the cavities can also cause this entity. Simultaneous rupture of the pericardium into the left and the right pleural spaces has also been described, as has herniation of the heart inferiorly into the peritoneal cavity.⁷⁴ There is a high incidence of associated injuries including musculoskeletal injuries that occur predominantly on the left side of the body. The organs most frequently involved in pericardial herniation are the transverse colon, stomach, omentum, liver, and small bowel. Exploratory laparotomy is recommended as the preferred approach for the acute repair of these injuries.⁷⁴

Diaphragmatic injuries may be associated with other severe life-threatening injuries as after blunt trauma or may be subtle in their presentation in a patient with a stab wound to the left thoracoabdominal area. In either situation a high index of suspicion is necessary to make the diagnosis. As modern imaging techniques improve, diagnosis may become less difficult. Once the diagnosis is made, repair in the acute phase can usually be accomplished using the surgical techniques described. In the latent or obstructive phases of presentation, repair or reconstruction of the diaphragm may be a surgical challenge. If gastrointestinal obstruction, perforation or ischemia occur with a chronic post-traumatic diaphragmatic hernia, postoperative morbidity and mortality are significant.