Rib Fractures

It’s the usual ED shift, when you see the next patient listed to be seen with a chief complaint of “Mechanism of Injury: Cyclist struck”.  As you rehearse ATLS while approaching the stretcher, you encounter a young male in his 30s laying in pain on the stretcher clutching his chest, taking obviously painful breaths. After a brief history, the physical exam yields tenderness to palpation over the left chest wall with surrounding abrasions, and you suspect multiple rib fractures to be present. With this, you order analgesia and imaging and start to consider, what is the appropriate disposition for this patient? What else should you be concerned for? Is there anything else that you could do to help improve the patient’s outcome?

Background

Trauma remains one of the highest sources of morbidity and mortality in the United States and is the leading cause of morbidity and mortality in those younger than 45 years (1). Blunt mechanism specifically comprises 15% of trauma presenting to the ED of which more than 35% of patients are diagnosed with rib fractures (2,3). Understanding the anatomy of the ribs helps better clarify the reasoning behind the management and complications commonly associated with rib fractures.

Figure 1
From: Iaizzo PA, 2009 (4)

There are twelve pairs of ribs located bilaterally, which are connected posteriorly to the spine and anteriorly to either the sternum or costal cartilage, except for “floating ribs” 11 and 12. The first three ribs are relatively protected by other structures, namely the scapula and clavicles. Given this layer of security, fractures of these ribs usually indicate high energy trauma, which should raise the suspicion for additional injuries. Ribs 4-10, by virtue of their location and anatomy, are the most prone to fractures by blunt trauma. Lastly, ribs 11 and 12 tend to be more mobile and hence, less likely to fracture. That said, when fractured, they are also predisposed to injuring adjacent viscous structures that they would otherwise protect.

During normal physiology, the ribs aid in chest wall movement to help lung expansion and inspiration. Rib fractures can inhibit this process both through pain and mechanical limitation, often referred to as “pulmonary splinting.” Pulmonary splinting can lead to the host of complications detailed below. In addition, rib fractures can lead to direct trauma of nearby structures, notably the lung.  

The typical signs and symptoms associated with rib fractures include chest wall pain, pain with inspiration, crepitus, chest wall tenderness, and ecchymoses. Other findings to note include decreased breath sounds, abnormalities in chest wall motion, and abdominal tenderness as they may indicate more worrisome complications associated with rib fractures.

Management

Labs and imaging remain part of the routine work up when evaluating patients with blunt trauma and suspected rib fractures. Complete blood count, chemistry panel, coagulation profile, and type and screens are standard and can help help identify abnormalities such as significant anemia, thrombocytopenia and coagulopathies. For imaging, chest x-rays are strongly recommended by the American College of Radiology when evaluating for rib fractures (5). This modality not only is fast and inexpensive, it can rapidly diagnose other complications such as pneumothorax and hemothorax. However, the sensitivity for rib fractures on plain films is low; a review by Murphy et al. showed that x-rays only picked up one third of rib fractures seen on CT (6). Despite this increased sensitivity, CT is not routinely recommended for exclusively diagnosing rib fractures, but perhaps when assessing for associated injuries, such as lung and thoracic vessel injuries (5). Another modality to consider is bedside ultrasonography since it can yield quick results when concerned for complications such as pneumothorax (i.e. loss of lung-sliding) and intra-abdominal injuries (i.e. positive FAST).   

Figure 2
From: https://radiopaedia.org/articles/rib-fractures (7)

Adequate analgesia and incentive spirometry are mainstays of treatment for patients with rib fractures. Not only are rib fractures painful, suboptimal analgesia is associated with increased morbidity and mortality (8). Adequate analgesia is crucial to overcome and prevent pulmonary splinting; if splinting persists, patients may be predisposed to pneumonia and respiratory failure by ways of atelectasis and tachypnea causing muscle fatigue, respectively (8,9).

A common stepwise approach for analgesia includes (1) oral analgesia, (2) parenteral analgesia, and (3) regional nerve blocks, which have been shown to especially effective to eliminate pain in patients with rib fractures (10). Ultimately, the goal of analgesia is not only to improve pain, but to improve respiratory mechanics; if adequate ventilation is not achieved, non-invasive positive pressure ventilation (NIPPV) should be considered as an adjunct.

Complications

Rib fractures usually indicate  presence of other injuries. A review of more than 7,000 patients by Ziegler et al. found that only 6% of trauma patients were diagnosed with isolated rib fractures (11). The most common and concerning complications associated with rib fractures include:

• Pneumothorax occurs when traumatic forces cause tearing of the pleura.  Pneumothoraces are associated with 37% of rib fractures. In these patients, consider chest tube placement when clinically indicated (12).
• Hemothorax occurs when thoracic trauma leads to vascular injury, causing an accumulation blood in the pleural space. It is associated with 27% patients with rib fractures. Consider chest tube placement in these patients as well (12).
• Pulmonary contusion is a result of capillary breakage and bleeding into lung parenchyma and has an prevalence of 17% of patients with rib fractures (12). Pulmonary contusion can have a delayed presentation on plain films. This process usually requires supportive care only, but may progress to ARDS.  
• Flail chest is defined as defined as 3 or more contiguous rib fractures leading to paradoxical motion of chest wall during breathing. This causes impaired respiratory mechanics and leads to increased risk of pneumonia and respiratory failure. Flail chest occurs in 5.8% of patients presenting with rib fractures and has an associated mortality of 16%. Flail chest requires aggressive care with analgesia, NIPPV, pulmonary hygiene, and possibly surgical repair (12,13).
• Pneumonia is a delayed complication of rib fractures and is a significant source of morbidity and mortality in rib fractures, especially in the elderly (9).
• Visceral injuries, specifically splenic and liver injuries, occur in 2-4% rate of patients presenting with traumatic rib fractures and are associated with fractures of lower ribs (14).

Disposition     

Once the diagnosis of rib fractures is made, and the appropriate analgesia and interventions are performed, where should the patient go? Young patients with minimal injuries and minimal comorbidities that are adequately treated with PO medications are generally safe to be discharged home. Patients diagnosed with pneumothorax, hemothorax, pulmonary contusion, flail chest, respiratory compromise, or those that require ongoing parenteral analgesia should be considered for admission. Providers should have a low threshold for admission of the elderly (>65 years) due to their comorbidities and the increased risk of pneumonia and death associated with rib fractures (9). There is also an increasing risk of morbidity and mortality with each broken rib, so each additional rib fracture should lower the threshold for admission (9). For the patients in between, there are no clear clinical practice guidelines, and often clinical experience guides decision-making. The Battle Score is one studied and validated tool that can be used to determine admission decision based on the predicted complication rates from blunt chest trauma:

Figure 3: The Battle Score for Predicting Complications from Rib Fracture
From: Battle C et al, 2014 (2)

If the patient is admitted, then supportive care, analgesia, and adequate monitoring for potential complications is important. If the decision is to discharge the patient, then it is important to schedule close follow-up, ensure adequate analgesia, and promote the use of incentive spirometry to help decrease adverse outcomes.

References

1. Kochanek KD, Murphy SL, Xu J, Arias E. Mortality in the United States, 2013. NCHS Data Brief 2014;178:1–9.
2. Battle C, Hutchings H, Lovett S, Bouamra O, Jones S, Sen A, Gagg J, Robinson D, Hartford-Beynon J, Williams J, et al. Predicting outcomes after blunt chest wall trauma: development and external validation of a new prognostic model. Crit Care 2014;18:R98.
3. Liman ST, Kuzucu A, Tastepe AI, Ulasan GN, Topcu S. Chest injury due to blunt trauma. Eur J Cardiothorac Surg 2003;23:374–8
4. Iaizzo PA. Handbook of cardiac anatomy, physiology, and devices. New York, NY: Springer; 2009.
5. Rib Fractures. American College of Radiology ACR Appropriateness Criteria 2014
6. Murphy C, Rodriguez R. Rib Fractures in the PanScan Era. Annals of Emergency Medicine 2016;68(4).
7. Knipe H. Rib fractures | Radiology Reference Article [Internet]. Radiopaedia.org. [cited 2018 Aug 14];Available from: https://radiopaedia.org/articles/rib-fractures
8. Karmakar MK, Ho AM. Acute pain management of patients with multiple fractured ribs. Advances in pediatrics. 2003
9. Morley E, Johnson S, Leibner E, Shahid J. Emergency Department Evaluation And Management Of Blunt Chest And Lung Trauma. Emergency Medicine Practice 2016;18(6).
10.  PECS/SERRATUS [Internet]. Highland EM Ultrasound Fueled pain management. [cited 2018 Aug 14];Available from: http://highlandultrasound.com/rib-fractures/
11. Ziegler DW, Agarwal NN. The morbidity and mortality of rib fractures. J Trauma. 1994;37(6):975-979.
12. Sırmalı M. A comprehensive analysis of traumatic rib fractures: morbidity, mortality and management. European Journal of Cardio-Thoracic Surgery 2003;24(1):133–8.
13. Dehghan N, Mestral CD, Mckee MD, Schemitsch EH, Nathens A. Flail chest injuries. Journal of Trauma and Acute Care Surgery 2014;76(2):462–8.
14. Athanassiadi K, Theakos N, Kalantzi N, Gerazounis M. Prognostic factors in flail-chest patients. Eur J Cardiothorac Surg 2010; 38:466.

Disclaimer: This post is primarily written for board review purposes and may not include current evidence-based information

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