Chest Wall and Diaphragm Injury

Abstract

Despite improvements in body armor, chest wall injuries are still common enough in combat settings that the surgeon must have more than passing familiarity with the management of them. The injuries can range from simple rib fractures to massive tissue and rib loss with eviscerated and injured lung, scapula or shoulder girdle involvement, hemorrhage, and open pneumothorax. The vast majority of chest wall injuries can be temporized with damage control measures until other pressing injuries and physiologic needs can be addressed and stabilized. The reconstruction of chest wall defects from tissue loss can and should be delayed until the patient is evacuated to higher levels of care, or at least until hemorrhage is well controlled, the patient resuscitated, and contamination/infection cleared up.

Civilian Translation of Military Experience and Lessons Learned

• William B. Long 

Key Similarities

• Diaphragm injuries are suspected based on mechanism of injury but can be difficult to confirm without operative exploration.

• Management of open pneumothorax , large traumatic chest wall defects, or impalements in civilian settings follows almost identical management algorithms as in military settings.

Key Differences

• Small diaphragmatic defects in stable penetrating trauma patients are much more common in civilian settings, are difficult to diagnosis with standard imaging modalities, and are amenable to laparoscopic and thoracoscopic techniques for diagnosis and management.

• Flail chest or multiple displaced rib fractures after blunt trauma are likely more common in civilian settings, are more likely to be closed fractures, and are therefore more amenable to early surgical rib fixation.

• Resource allocation and the remote locations associated with the military setting pose additional challenges that may require more temporizing with damage control techniques and staged approaches to chest wall and diaphragm injuries.

Discussion

Dr. Beekley and Dr. Tadlock’s chapter on chest wall and diaphragm injury provides an excellent primer on the management of diaphragmatic injuries, chest wall defects, and open pneumothorax , particularly in the setting of combat and injury from explosive or high-velocity weapons. These injuries are frequently obvious in those settings. Chest wall defects resulting in open pneumothorax are often dramatic, and the diaphragmatic injuries are often found incidental to exploration for control of hemorrhage and contamination in the chest and abdomen from these wounding mechanisms. While less common in civilian settings, these injuries are nevertheless encountered on occasion and should be managed by the principles outlined in the chapter.

In civilian settings, blunt trauma predominates and the penetrating injuries are more often caused by low energy/velocity mechanisms (e.g., stab and handgun wounds). Consequently, diaphragm injuries may be more difficult to diagnosis and a high index of suspicion must be maintained based on the mechanism and location(s) of injuries. Despite the wide array of imaging modalities available, small diaphragmatic defects from penetrating thoracoabdominal wounds can easily be missed and result in delayed presentation with diaphragmatic herniation, visceral obstruction, and even strangulation. Fortunately, these injuries are relatively easy to diagnose and repair at initial presentation via minimally invasive surgical techniques (primarily laparoscopy), modalities frequently not available in deployed military settings.

There is also a continually evolving understanding of rib fractures, and there are now multiple hardware sets specifically designed for surgical rib fixation. Many civilian centers have begun to expand the indications for surgical rib fixation beyond flail chest, with the recognition that there are longer term consequences to rib fractures in terms of pain, function, and disability than previously thought. These interventions are still under intensive study and the indications for surgical rib fixation in terms of number and location of rib fractures, objective functional criteria (e.g. VC, FEV1, and incentive spirometry performance), are still a matter of debate. The authors of this chapter are appropriately cautious in recommending that rib fixation be reserved for selected patients only at Role 3 facilities and higher.

Although the authors’ chapter is fairly comprehensive, there are a few fine points gained from years of experience that can be added to expand or refine their recommendations. These are added below.

Chest Wall Defects

Small chest wall defects (<4 cm in diameter) can be covered with an occlusive dressing. There is a theoretical advantage to placing a chest tube through a separate tube thoracostomy site in the chest wall, but the pleural cavity is already contaminated. Why add a new incision in the chest if you don’t need to? Put a chest tube in the hole already made by the projectile or object and secure the tube with sutures and wrap the Ioban around it. This chest tube is or others are temporary!

The decision to explore the pleural cavity can then be based on chest tube output of a massive air leak or blood, and other findings on chest X-ray, as is discussed in the chest injury section. Chest CT scans are helpful to assess lung damage and whether the lung is ripped, has a large lobar hematoma, a traumatic injury to the thoracic aorta, mediastinal hematoma, pneumopericardium, or unsuspected hemopericardium. Distance and time to the next echelon of care factors into these decisions. Otherwise CT of the chest is rarely needed in the acute setting to make this decision.

Large air leaks can be decreased with bronchial blockers of lobar or segmental bronchi in an emergency to buy time until the patient can be transferred to a higher echelon of care.

Irrigation or pulse lavage of the chest wall and pleural cavity is helpful to decrease contamination.

Flail Chest

There are many types of flail chest, ranging from sternal flail, parasternal flail, anterolateral flail, lateral flail, and paravertebral flail, each with its own unique challenges for reconstruction. Please make every effort to save large rib fragments (those than can hold two more screws) with attached viable intercostal muscles for later incorporation into a plated rib repair.

Organ Herniation Through the Chest Wall

Organs that can herniate though intercostal rib fractures include part of a lung, a whole lobe, liver, and spleen, with accompanying injury of a diaphragm. Organs that can herniate though intercostal rib fractures include part of a lung, a whole lobe of a lung, liver, and spleen. Any of these can present with accompanying injury of a diaphragm. Most of the time the skin is intact.

A CT scan of the chest wall with IV contrast helps to make the diagnosis of organ herniation. Unless there is danger of compromise of an organ’s blood supply, most organ herniation can be managed initially as a patient with an open chest wound, if the herniated organ is exposed. If not exposed and the organ blood supply is satisfactory, the patient can be referred to a higher echelon of care for definitive care.

Impalements of the Thorax

Impalements of the chest can happen in both civilian and military combat settings, as patients can fall onto a stake, a metal fence post, Rebar, a tree limb, or a piece of equipment. Patients who survive an impalement can usually make it to the nearest casualty center. The biggest threat to the patient’s life is either the patient pulls out the impaling object or somebody else does. This can cause exsanguinating hemorrhage or open pneumothorax . The wound and impaling object are always considered contaminated.

The prehospital care providers need training for extricating the patient from the scene while keeping the impaled object in the patient. This may require tools to cut the impaling object as it enters and or exits from the chest. Then the patient can be transported.

Removal of impaled objects of the thorax should be done in the OR with portable fluoroscopy equipment available. If this is not available, then the surgeon has to decide whether of transport the patient to a higher echelon of care or remove the impaling object with a thoracotomy .

Traumatic Pericardial Herniation

This rare entity can happen with both high energy blunt trauma , blast type concussion to the chest wall, and theoretically with penetrating injury. The left ventricle and part of the right herniates through the rent in the pericardium, and the pericardium constricts the heart in the atrioventricular groove, producing partial inflow occlusion and marked hypotension. The patient with this entity does not transport well. The patient should undergo a left anterolateral thoracotomy in the partial right lateral decubitus position to expose the left side of the heart. The edges of the pericardial rent are grasped with Allis clamps which are pulled gradually outward and the heart will have a few beats of tachycardia, and then reduces itself. The pericardium can be loosely reapproximated with 3-0 silk sutures and drained with a Blake drain.

Conclusion

It is incumbent on all trauma surgeons, both civilian and military, to learn the principles in diagnosis and management of these often challenging injuries, as the specter of mass shootings and terror attacks with explosive devices continues to blur the lines between civilian and military trauma.