Blunt Trauma as a Cause of Rib Chondro-osteitis: A Case Study
Rib chondro-osteitis is rare and usually caused by tuberculosis. A 63-year-old man presented with fever, painful swelling, and a burning sensation in the parasternal right submammary region. He had a history of cardiac interventions: percutaneous transcatheter angioplasty with stenting 1 year prior and coronary artery bypass graft surgery 16 years before; therefore, he was on dual antiplatelet therapy. He sustained blunt chest trauma 5 months before admission.
A chest wall abscess was suspected and fine needle aspiration of the lesion revealed the presence of purulent fluid. Culture results were positive for Staphylococcus aureus and intravenous antibiotic therapy was started. Computed tomography showed a lesion involving the sternal, chondral, and proximal costal portions of the fourth, fifth, and sixth anterior costal arches. The patient was diagnosed with costal chondo-osteitis following blunt trauma.
Following aggressive surgical debridement, the wound was managed with topical negative pressure therapy (constant -125 mm Hg setting with daily dressing changes). After 15 days, culture results were negative, the wound bed contained healthy granulation tissue, and the defect was surgically closed using a myocutaneous flap. No recurrence or complications have been observed during the 2-year follow-up. This is the first reported case of pyogenic, posttraumatic, costal chondro-osteitis secondary to a blunt trauma of the chest wall.
Potential Conflicts of Interest: none disclosed
Osteitis of the ribs is a rare disease in the antibiotic era1–3; tuberculosis, responsible for most hematogenous forms, is the most frequent etiological factor for osteitis occurring in developing countries.2 The only relatively recent report (by Bishara et al3) describes 106 cases of rib osteomyelitis: mycobacterial and bacterial infections accounted for 88% of cases, fungal infection was the second most common etiology (10%), and the majority of patients were children and young adults (mean age 26 years). Pyogenic rib infection may be a complication following either a surgical thoracotomy or a penetrating trauma; Staphylococcus aureus is the most frequently encountered causative agent.4 In cases of S. aureus, the etiological mechanism is bacterial contamination from a skin wound. Similarly, osteomyelitis of the ribs associated with deep sternal wound infections is rarely encountered following cardiac surgery; if it occurs, it is usually observed in the early postoperative months.1
Rib osteomyelitis usually involves the anterior or posterior costal arch and consists of the colliquative degeneration of both bone and chondral portions of the ribs. Hence, rib osteomyelitis should be diagnosed as chondro-osteitis. Both the hematogenous and the penetrating mechanisms of inoculation imply the infection propagated from within the bone; therefore, surgical excision of the affected segments of the rib is crucial for successful treatment. Generally, combined surgical and medical therapies are employed.
The use of topical negative pressure wound therapy (NPWT), an emerging option for wound healing,5,6 has never been reported in the literature for the management of rib chondro-osteitis. However, it has been reported to be successful in a case series of 13 patients with deep infections following surgical thoracotomy7 and in the management of thoracotomy infections in a pediatric patient at the present authors’ institution.8
Mr. K, a 63-year-old grocer with a history of diabetes mellitus (controlled with oral hypoglycemics), hypertension, hypercholesterolemia, and multiple myocardial infarctions between 1982 and 1992, underwent triple coronary artery bypass graft surgery in 1992. In 2007, a percutaneous transcatheter angioplasty was performed with stenting of the left anterior descending coronary artery, at which time clopidogrel was prescribed in adjunct to the antiplatelet therapy with acetylsalicylic acid that he used previously.
Mr. K was readmitted to the authors’ hospital in April 2008 with a 10-day history of fever, painful swelling, and a burning sensation in the parasternal right submammary region. The previous sternotomy incision appeared completely normal. Mr. K reported that 5 months earlier he had experienced a blunt chest trauma — a 25-Kg bologna sausage had accidentally fallen on his chest.
A chest wall abscess was suspected. Fine-needle aspiration of the lesion revealed the presence of purulent fluid. Culture results, including fungal-specific cultures, grew methicillin-sensitive S. aureus. Two sets of blood cultures were negative for bacterial and fungal growth.
A chest x-ray showed signs of reduced bone density at the anterior portion of the fifth right rib with extension to the junction between costal cartilage and sternum; no pathologic findings were observed at the site of the previous sternotomy.
A computed tomography (CT) scan of the chest showed the previous sternotomy appeared normal with no evidence of diastasis of the sternal edges. However, a massive amount of purulent fluid was observed within the subcutaneous layer at the distal end of the right parasternal area. Fluid collection extended approximately 7 cm into the craniocaudal and 4.5 cm along the transverse diameter and the anteroposterior direction; at the superior level, the fluid extended toward the right side, causing thickening and structural inhomogeneity of the homolateral pectoral muscle. At the level of the right pectoral region, the lesion reached the maximum thickness of 2.9 cm, 8 cm along the transverse axis and 5.5 cm on the craniocaudal extension. The purulent collection reached the medial and chondral portion of the anterior arches of the fourth, fifth, and sixth right ribs. The most severe structural involvement was evident at the level of the fifth costal arch (see Figure 1).
Immediately after cultures were obtained, empirical antibiotic therapy was started with 2.2 g amoxicillin-clavulanic acid every 8 hours. When the culture results became available on day 3 of hospitalization, the amoxicillin dose was increased to 2.2 g every 4 hours and debridement surgery was planned for the following day.
An anterolateral submammary incision was made under general anesthesia. Extensive debridement was performed, involving the subcutaneous tissue, the muscular plane, and the costal arches. The inflamed pericostal tissue was resected at the level of the anterior arch of the fourth, fifth, and sixth right ribs up to the condrosternal junction. However, no portion of the affected ribs, albeit widely scraped by debridement maneuvers, was excised.
The standard vacuum-assisted closure (VAC) system (V.A.C. Therapy®, KCI, San Antonio, TX)5,6 was applied in the operating room using a constant negative pressure setting of –125 mm Hg. Dressings were changed every 24 hours with no anesthesia necessary and swab cultures were obtained every 3 days. On postoperative day 15, when culture results were no longer positive, the wound bed was uniformly filled with granulation tissue. When the size of the wound bed had reduced from 15 cm (initial length of the surgical incision) to about 10 cm, the wound was surgically closed using a myocutaneous flap. Antibiotic therapy was continued in the hospital for a total of 3 weeks. No complications from NPWT were observed throughout the hospital stay period. Among salient laboratory values, Mr. K’s white blood cell count decreased progressively from 21,000/mm3 at admission to 8,800/mm3 on day 15 following surgery. His fasting blood glucose was 122 mg/dL at admission and 105 mg/dL the day after; it increased to 176 mg/dL after NPWT initiation, then decreased the following day and remained within the normal range throughout hospital stay. C-reactive protein was 67 mg/L upon admission, 23 mg/L after 1 week, 18 mg/L after 2 weeks, and 4.5 mg/L the day before discharge. Creatinine clearance remained normal throughout admission.
Mr. K was discharged on postoperative day 23 and thereafter was seen on an outpatient basis, monthly for the first 6 months, then every 2 to 3 months. During the next 2 years, no evidence of reinfection was observed, either clinically or through laboratory investigations.
Rib chondro-osteitis in cardiothoracic surgery patients has been previously described as the extension of a deep sternal wound infection complicating a median sternotomy; it is generally observed in the early postoperative period. Delayed chest wall complications of median sternotomy also have been described,9 but they generally occur within the first four postoperative months. Purulent discharge or painful chest wall swelling are the two most common presentations of rib osteomyelitis; aspiration of pus from the lesion may be helpful for an early diagnosis. Although a routine chest x-ray may fail to detect early chest wall infections, a chest CT can accurately demonstrate rib lesions and changes of the overlying soft tissues and pericostal edema can be readily diagnosed by ultrasound scanning.10
The patient in this case report presented with characteristics not previously reported in the medical literature. The rib osteitis was a new event that occurred several years following sternotomy and the original wound appeared to be completely unrelated to the costal infective focus. In the current case, rib chondro-osteitis appeared to be the result of a blunt trauma and no inoculation was demonstrated, in contrast with the posttraumatic cases described in the literature.3 The occurrence of rib chondro-osteitis in this immunocompetent patient, with no apparent risk factors, could be related to the following putative mechanism: the reported blunt trauma and aggressive dual antiplatelet therapy he was receiving may have prompted the formation of a deep chest wall hematoma, surrounding the anterior costal arch. A spontaneous bacteriaemia nay have caused S. aureus to seed at the level of the pericostal hematoma, secondarily involving the ribs from the outside.
The use of topical NPWT following surgery for chondro-osteitis also has not been reported previously. Mr. K responded well to the combination of intravenous antibiotic and topical NPWT, and the wound was able to be surgically closed after 15 days of treatment. No radical excision of the affected ribs was necessary and the NPWT dressing sponges were applied just over the pericostal plane.
The literature2,3 recommends a combined surgical and medical approach to treat rib osteitis. Treatment generally includes aggressive subperiostal excision of the affected part of the ribs — extending debridement to the chondro-sternal junction — combined with a targeted antibacterial drug regimen. Generally, the wound is left open with daily dressing changes and complete healing may require months that sometimes involve surgical re-explorations and excision of unhealthy rib ends. Because the incidence of rib osteitis is very low, this usual treatment modality is recommended on the basis of outdated observational reports and case studies involving only a small number of patients.2,3,10 In Mr. K’s case, secondary surgical reconstruction of the chest wall was simple and he was discharged after a relatively short and uneventful hospital stay. Pleural complications (eg, empyema) of infected thoracotomies as reported by others11 did not occur. The decision to use NPWT, avoiding aggressive bone resection, was guided by the authors’ previous success with this treatment in the management of deep sternal wound infections and thoracotomy infections following cardiothoracic surgery in both adult and pediatric patients8,12 and its success reported in other case series.7 All patient outcomes are the result of a variety of factors. Because these infections are rare, treatment continues to be guided by reported case studies and case series. In this case, the medical and surgical interventions described led to an excellent outcome while avoiding extensive bone resection and facilitating secondary surgical closure.
Rib osteomyelitis, a rare condition in developed countries, usually presents in a hematogenous form or secondary to a wound infection following penetrating trauma or surgery. This case study suggests that other mechanisms (ie, blunt trauma) also may cause rib chondro-osteitis. The excellent outcome achieved with surgical debridement (even without rib excision), culture-guided antibiotic therapy, and NPWT suggests that evaluations of this approach in the management of more commonly observed forms of rib osteomyelitis are warranted.
Dr. De Feo is Associate Professor of Cardiothoracic Surgery, Department of Cardiothoracic Sciences, Second University Naples, V. Monaldi Hospital, Naples, Italy. Dr. Rossi is a staff radiologist, Department of Radiology, V. Monaldi Hospital. Dr. Durante-Mangoni is Research Professor of Internal Medicine, Department of Cardiothoracic Sciences, Second University Naples, V. Monaldi Hospital. Dr. Cotrufo is a full Professor of Cardiothoracic Surgery, Department of Cardiovascular Surgery, “Pineta Grande” Hospital, Castelvolturno (CE), Italy. Dr. Della Corte is a Research Professor of Cardiothoracic Surgery, Department of Cardiothoracic Sciences, Second University Naples, V. Monaldi Hospital. Please address correspondence to: Alessandro Della Corte, MD, PhD, V. Monadi Hospital, Via L. Bianchi, 80131 Naples, Italy; email: firstname.lastname@example.org.