The indications for surgery in flail chest and rib fracture repair are summarized in Table 137-1. Both acute and chronic problems are amenable to surgery.
Table 137-1Potential Indications for Repair of Rib Fracture ||Download (.pdf) Table 137-1Potential Indications for Repair of Rib Fracture
|Flail chest inclusion criteria |
Failure to wean from ventilator
Paradoxical movement visualized during weaning
No significant pulmonary contusion
No significant brain injury
|Reduction of pain and disability |
Painful, movable rib fractures
Failure of narcotics or epidural pain catheter
Fracture movement exacerbates pain
Minimal associated injuries (AIS <2)
|Chest wall deformity/defect |
Chest wall crush injury with collapse of the structure of the chest wall and loss of thoracic volume
Severely displaced, multiple rib fractures or tissue defect that may result in permanent deformity or pulmonary hernia
Severely displaced fractures are significantly impeding lung expansion or rib fractures are impaling the lung
Patient is expected to survive any other injuries
|Symptomatic rib fracture nonunion |
CT scan evidence of fracture nonunion (>2 mos after injury)
Patient reports persistent, symptomatic fracture movement
Thoracotomy for other indications (i.e., “on the way out”)
Flail chest is a complex injury involving multiple rib fractures that cause a segment of the thoracic cage to separate from and move independently of the remaining chest wall. To be classified as flail chest, the segment must involve at least two consecutive ribs, and each rib must have a minimum of two fractures. Large fail segments involve more than two ribs, a greater proportion of the chest wall, and often extend bilaterally or involve the sternum (Fig. 137-1). Flagel et al. found that age greater than 45 years and presence of six or more rib fractures are associated with a worse prognosis and higher complication rate. They further reported that the larger the force applied to the chest wall, lungs, and intrathoracic organs, the greater the severity of pain and physiologic derangement.11
Flail chest and flail mediastinum.
Clinically, flail chest is diagnosed when an unstable segment of the rib cage causes paradoxical motion of the chest wall visible on respiration (Fig. 137-2 A,B). Sternal flail occurs when the sternum becomes dissociated from the hemithoraces as a result of either unilateral or bilateral rib fractures associated with costochondral dissociation. These anatomical and mechanical changes will eventually lead to respiratory fatigue, inadequate ventilation, atelectasis, ventilation/perfusion mismatch (shunt), hypoxemia, and pulmonary failure (Fig. 137-3). Two randomized trials have been conducted supporting the notion that selected patients with flail chest may experience short- and long-term benefits from operative repair. The surgically repaired groups in both trials demonstrated significantly fewer days on the ventilator and in the ICU, and had a lower incidence of hospital-acquired pneumonia, better pulmonary function at 1 month follow-up, and a higher rate of return to work at 6 months compared with the nonoperative groups. Visual chest wall deformity or persistent flail chest occurred less frequently in the operative groups, whereas forced vital capacity and total lung capacity were significantly higher in the operative groups at 2 months.12,13
Paradoxical motion of the chest wall caused by at least two adjacent fractured ribs. This causes paradoxical breathing, with the lung underlying the injured area contracting on inspiration and bulging on expiration and mediastinal swing with hemodynamic instability.
The pathophysiology of respiratory failure secondary to flail chest.
Recent, nonrandomized, cohort comparison trials have generally confirmed these findings with the caveat that flail chest repair is usually not advised in patients with significant pulmonary contusions.14–16 The optimal number of days after injury to perform repair is controversial: one trial randomized patients at 5 days12 and the other at 36 to 48 hours.13 In our experience, the repair can be safely performed up to 15 days after injury, before a healing callus begins to form around the fractures, as after this point the callus must be removed to achieve complete alignment of the rib fragments and bony union.
On the basis of our 10-year clinical experience, we developed a new classification for flail chest (Table 137-2), using the vector of the force (blow) applied to the chest (Fig. 137-4) as a guide to determining the optimal approach for treatment of complex chest wall injuries.17 The chest wall is similar to a ring. When sufficient force is applied to one side of the ring, the energy associated with the force is transmitted to the opposite side. Depending on the magnitude of the force, the structures contained within the chest, such as the lung, heart, and mediastinal structures, may cause the ring to break at two points. Most patients presenting with flail chest have unilateral flail segments with minimal respiratory derangement. These injuries are classified as type I. The majority of these patients can be treated with pain management, respiratory therapy, and early ambulation. Patients with type II injuries require repair of at least one side of the chest, since the intrathoracic structures will have absorbed some of the force transmitted to the opposite side. The exception is the patient who sustains a lateral blow followed by a “counter coup” injury. Patients presenting with type III, IV, and V flail chest have sustained substantial trauma to their chest, and most likely require immediate surgical repair. Figure 137-5 offers a simplified guideline for the management of rib fracture and flail chest.
Vector of force blow applied to the chest wall, lateral, bilateral, frontal, diagonal (seat belt injuries) and downward displacement.
Simplified guideline for repair of rib fractures.
Table 137-2Proposed Classification for Flail Chest ||Download (.pdf) Table 137-2Proposed Classification for Flail Chest
|TYPE ||COMPARTMENTS ||VECTOR OF FORCE |
|I ||Lateral, one side only ||Lateral blow (R or L) |
|II ||Bilateral ||Lateral blow (R and L) |
|III ||Central Sternal fracture-costochondral disruption +/– rib fractures ||Anteroposterior blow to the chest and sternum |
|IV ||Mixed (III + I or II) ||Anteroposterior blow to the chest and sternum + lateral blow |
|V ||Lung herniation or intrathoracic visceral herniation, or Lung destruction with any of the above ||Any of the above combinations usually require thoracotomy for repair |
Chest wall defects/deformities occur in a variety of traumatic circumstances and are characterized by severely displaced rib fractures that visibly deform the chest wall with or without soft tissue loss. Paradoxical motion may not be present in many of these patients, especially in patients with adequate pulmonary reserve. Minimal to moderate-sized tissue defects (<10 × 10 cm) can be caused by penetrating missiles or impalement by surrounding objects during a motor vehicle crash (MVC) or fall. Repair of both rib fractures and soft tissue may be indicated to restore an incompetent or “caved in” segment of the chest wall. Nonoperative management will eventually lead to the development of chest wall herniation. Larger chest wall defects, such as those resulting from close-range shotgun blasts or explosions should be repaired by a multidisciplinary team, including plastic, orthopedic, and neurosurgeons. Diaphragmatic transposition, involving detachment of the diaphragm peripherally and suture above the chest wall defect, has been described for lower chest wall defects.18 This procedure converts the chest wall injury to an abdominal wall defect and provides soft tissue support for the rib cage.
Acute Pain and Disability Reduction
The majority of rib fractures heal without complications and long-term disability. However, patients may present several months after traumatic injury with displaced and movable rib fractures. These patients do not require assisted ventilation, such as BiPAP, but do experience persistent, unrelenting pain with respiration, coughing, or mobilization. Such patients may benefit from having their fractures surgically stabilized. One should exercise clinical judgment, however, and disclose the risks of long-term pain and disability that may persist despite a successful surgical repair.
A small percentage of rib fractures do not heal, presumably because the angulation and displacement of the fracture is too severe. Although a fibrous capsule may envelope the fracture, bony union has not occurred. A chronic nonunion may cause intermittent discomfort associated with movement of the fracture and can be quite disabling for the patient. The rationale for nonunion repair is based on the assumption that without intervention, complete bony healing will not occur. It is of paramount importance that the fibrous callous enveloping the nonunion be resected and a plate placed to fixate the rib ends.
Thoracotomy for Other Indications
A patient with multiple rib fractures or flail chest who needs a thoracotomy for another indication, for example, open pneumothorax, pulmonary laceration, retained hemothorax, or diaphragm laceration, is a candidate for rib fracture repair provided it does not increase the morbidity of the original operation. Otherwise the repair should be delayed and undertaken when the patient is stable. Thoracotomy for nontraumatic indications, for example, tumor resection, also may result in rib fractures that may need to be surgically repaired.
Technical Considerations of Rib Fracture Repair
The goals of rib fracture repair are to target unstable fractures and flail chest segments, improve respiratory function, promote early separation from mechanical ventilator support, ensure early ambulation, decrease the need for prolonged pain medication, decrease recovery time, and accelerate the patient's return to work. The chest anatomy is unique owing to the tight association between the mechanical properties of the chest wall, muscles, and ribs with the underlying lung parenchyma, heart, and mediastinal structures (Fig. 137-6). The human rib thickness ranges from 8 to 12 mm and has a relatively thin (1–2 mm) cortex that surrounds the soft marrow. Individual ribs do not have an abundance of stress tolerance, and the rib with its thin cortex does not hold a cortical screw as well as bone, which has a thicker cortex. Rib fractures may be comminuted, oblique, displaced, or fragmented in several areas along the same rib, further increasing the challenge for a reliable repair. In addition, the intercostal nerve lies along the undersurface of the rib. Intercostal nerve injury during operation or crimping may lead to post-thoracotomy pain syndrome.
Rib cage, lung parenchyma, and mediastinal structures.