Prior to the 1950s, the approach to treating skeletal trauma or deformity of the chest was largely nonoperative. Advances in anesthesia, cardiothoracic surgery, bioprosthetic materials, and mechanical ventilation in the second half of the 20th century reduced the morbidity and mortality of operating in the chest, creating a safer environment for surgical intervention. Potential indications for rib fracture repair include flail chest, non-united rib fractures refractory to conventional pain management, chest wall deformity or defect, and trauma-associated rib fracture and respiratory failure which may be repaired during thoracotomy for other traumatic injury. Several effective repair systems have been developed. These have made plating of ribs and stabilization of the chest wall safe, effective, and easy to perform. Future directions for progress on this important surgical problem include the development of minimally invasive techniques and the conduct of multicenter, randomized trials. In this chapter, we propose a unique classification for flail chest based on vector force applied to the chest wall and its underlying physiologic response to that force.

Flail chest has been alternately described as “stoved-in” or “crushed” chest. Nonoperative approaches have included external strapping, placement of sandbags, or positioning of the patient with the injured side down. These methods have been used with relative success to stabilize unilateral flail chest, but for complex injuries, such as bilateral flail chest, mediastinal flail, and large chest wall soft tissue defects, a different strategy is clearly required. External fixation combined with traction was eventually described and largely used during the initial phase of management of flail chest. The prolonged bed rest necessary for fracture union, however, led surgeons to consider internal fixation. Intramedullary “rush nail” fixation was first reported in 1956.¹ Another major factor was the introduction of positive pressure mechanical ventilation. Its adoption and success in preventing respiratory failure in patients with multiple rib fractures and flail chest rendered external fixation/traction obsolete.

By the 1960s and 1970s surgeons recognized that select patients with flail chest might benefit from surgical fixation even after brief periods of mechanical ventilation had failed. Sporadic series attempting rib fracture repair using a number of techniques, including plating, wiring, and intramedullary rods, were reported.^2–9 Brunner was the first to successfully repair a case of sternal flail using a substernal stainless steel prosthesis, the same technique used to reconstruct pectus excavatum.¹⁰

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.

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

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

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.