SUMMARY Flail chest is a traumatic chest injury defined as segmental fractures of 3 or more consecutive ribs and is often associated with pulmonary injuries such as hemothorax and pneumothorax. Diagnosis is made with radiographs of the chest. Treatment can be nonoperative or operative depending on the presence of respiratory compromise, the number of consecutive rib fractures, and the presence of open fractures. EPIDEMIOLOGY Incidence approximately 300,000 cases per year, 7% require hospitalization for medical and/or surgical treatment greater number of fractured ribs correlates with increased morbidity and mortality ribs 7-10 are most commonly fractured Demographics bimodal distribution younger patients involved in trauma older patients with osteopenia ETIOLOGY Mechanism direct blunt vs penetrating trauma fracture at the site of impaction or at the angle (i.e. posterolateral bend) of the rib (i.e. biomechanically weakest point) pathologic / metastatic Associated Injuries fractures involving ribs 1, 2, or 3 associated with mediastinal injury (aorta or brachial plexus) and worse mortality fractures involving ribs 9 through 12 are associated with intra-abdominal organ injuries (hepatic and splenic most common) scapula fractures hemopneumothorax and/or pulmonary contusions clavicle fractures risk for progressive clavicle fracture displacement with ipsilateral upper rib fractures (i.e. ribs 1-4) ANATOMY Osteology 12 pairs of ribs; numbered 1 through 12 according to the corresponding thoracic vertebra to which they are connected posteriorly anterior ribs articulate with the sternum via the costal cartilage ribs 11-12 are "floating ribs" without anterior sternal costal cartilage attachment Neurovascular supply intercostal neurovascular bundle lies posterior-inferiorly adjacent to each rib within the costal groove PRESENTATION Symptoms pain bruising along chest wall respiratory difficulty Exam paradoxical respiration area of injury "sinks in" with inspiration, and expands with expiration (opposite of normal chest wall mechanics) chest wall deformity can be seen bony or soft-tissue crepitus is often noted IMAGING Radiographs low sensitivity with standard AP and lateral radiographs dedicated rib radiographs are more sensitive (added oblique views and higher energy radiation) may see associated hemothorax CT improved accuracy of diagnosis with CT (vs. radiographs) also shows associated thoracic or abdominal injuries best modality to assess displacement, segmental injuries, and need for surgery TREATMENT Nonoperative observation indications no respiratory compromise no flail chest segment (>3 consecutive segmentally fractured ribs) techniques supplemental O2 as needed incentive spirometry multimodal pain control Operative open reduction internal fixation indications displaced rib fractures associated with intractable pain recalcitrant to conservative measures flail chest segment (3 or more consecutive ribs with segmental injuries) rib fractures associated with failure to wean from a ventilator open rib fractures symptomatic nonunion follow Chest Wall Injury Society recommendations for surgical stabilization of rib fractures (SSRF) techniques plate and screw constructs intramedullary splinting outcomes surgical repair of flail chest has been shown to reduce rates of pneumonia, permanent chest deformity, and mortality also shown to reduce the need for tracheostomy, duration of mechanical ventilation, shorter ICU/hospital stays, and overall cost savings Techniques open reduction and internal fixation technique approach lateral thoracotomy treats anterolateral and posterolateral fractures with lateral decubitus positioning posterior paramedian approach treats very posterior rib fractures near costovertebral junction inframammary approach treats anterior fracture and costochondral dislocations via supine positioning contraindications hemodynamic instability spinal or pelvic fractures that must be stabilized before rib fixation COMPLICATIONS Nonunion persistent chest pain >3 months after injury obtain nonunion workup before fixation Intercostal neuralgia avoid injuring the intercostal neurovascular bundle during plating (located posteroinferior to rib) Periscapular muscle weakness Pneumonia Restrictive type pulmonary function PROGNOSIS Mortality rate as high as 33% when flail chest is present, 2.5% with surgical stabilization