What is the management approach for a patient with a history of cardiac surgery via sternotomy, presenting with tenderness to the right of the sternotomy scar upon palpation?

Management of Tenderness Right to Sternotomy Scar on Palpation

Post-sternotomy pain is common, affecting more than half of patients after cardiac surgery, and requires systematic evaluation to distinguish benign musculoskeletal pain from serious complications like sternal wound infection, dehiscence, or cardiac issues. 1

Initial Clinical Assessment

Key Physical Examination Findings to Evaluate

• Assess for sternal stability: Palpate for sternal gap >3 mm, which correlates with significantly higher chest pain intensity and indicates sternal nonunion or dehiscence 1
• Examine for signs of infection: Look for erythema, warmth, purulent drainage, or fluctuance suggesting superficial or deep sternal wound infection 2
• Check for systemic signs: Fever, tachycardia, or hemodynamic instability may indicate mediastinitis or other serious complications 3
• Evaluate pain characteristics: Post-sternotomy pain syndrome presents as discomfort persisting for at least 2 months without apparent cause, with incidence ranging from 7% to 66% 1, 4

Timing Considerations

• Early postoperative period (<17 days): CT has 100% sensitivity but only 33% specificity for mediastinitis, as normal postoperative changes can mimic infection 1
• Beyond 17 days: CT sensitivity and specificity improve to 100% and 90% respectively for diagnosing mediastinitis 1
• Chronic pain (>2 months): Consider post-sternotomy pain syndrome, which is more prevalent in women within the first 3 months (51.4% vs 31.3% in men) 1

Diagnostic Imaging Strategy

When Imaging is Indicated

Order CT chest with contrast if any of the following are present:

• Clinical suspicion of sternal wound infection despite equivocal physical findings 1
• Concern for sternal dehiscence or nonunion based on palpable instability 1
• Need to assess degree of osseous healing and residual chest wall deformities 1
• Evaluation for alternative diagnoses if pain pattern is atypical 1

Advanced Imaging Considerations

• FDG-PET/CT: Useful for determining depth of infection and involvement of costal cartilages when deep sternal wound infection is suspected, with sensitivity 91% and specificity 97% for sternal wound infections (particularly valuable >6 months post-surgery) 1
• Bone scan: Maintains high negative predictive value for osteomyelitis in patients with equivocal CT findings 1

Management Algorithm

For Uncomplicated Post-Sternotomy Pain (No Red Flags)

Initiate multimodal analgesia:

• First-line: Acetaminophen 650 mg every 6 hours or 975 mg every 8 hours 5
• Add: Ibuprofen 600 mg every 6 hours for anti-inflammatory effect if not contraindicated 5
• Reserve opioids: Only for severe pain not controlled by non-opioid analgesics 5
• Consider osteopathic approaches: May successfully eliminate pain in select patients with post-sternotomy pain syndrome 4

For Suspected Sternal Dehiscence or Nonunion

• CT chest with 3-D reconstructions to characterize sternal gap and assess healing 1
• Sternal gap >3 mm requires surgical consultation for potential restabilization 1
• Incomplete osseous healing inversely correlates with pain intensity 1

For Suspected Deep Sternal Wound Infection

This is a surgical emergency with mortality up to 50%: 3

• Immediate surgical consultation for debridement 3
• CT chest to assess extent of infection and mediastinal involvement 1
• Consider FDG-PET/CT for preoperative planning of debridement procedures 1
• Long-term drainage with continuous lavage or negative pressure wound therapy for wound conditioning 3
• Radical debridement is the key point for successful treatment 3

Critical Pitfalls to Avoid

• Do not dismiss persistent pain as "normal": Pain persisting beyond 2 months warrants thorough evaluation 1, 4
• Avoid premature CT in early postoperative period: High false-positive rate in first 17 days post-surgery 1
• Do not overlook cardiac causes: In patients with prior CABG, acute graft stenosis/occlusion, pericarditis, or PE must be excluded 1
• Recognize that multiple pain mechanisms can coexist: Musculoskeletal pain, nerve entrapment, and infection may occur simultaneously 5
• Do not delay imaging if infection suspected: Deep sternal wound infections have devastating mortality and require urgent intervention 3

When to Escalate Care

Immediate cardiothoracic surgery consultation if:

• Signs of deep sternal wound infection or mediastinitis 3
• Sternal dehiscence with instability 1
• Hemodynamic compromise or signs of cardiac tamponade 1
• Progressive symptoms despite conservative management 4