Seeing is Believing? Preoperative Magnetic Resonance Imaging for Pressure Ulcers: Implications for Surgical Management

BACKGROUND Pressure ulcers represent a particularly difficult disease process and remain a financially important entity. The underlying bone in advanced ulcers may harbor osteomyelitis. Radiologic diagnosis of osteomyelitis is confounded by chronic pressure and shear. We sought to determine the test characteristics of preoperative magnetic resonance imaging (MRI) in the diagnosis of osteomyelitis compared to intraoperative bone culture. METHODS A retrospective review of patients undergoing flap reconstruction who had preoperative MRI and intraoperative bone cultures between 1995 and 2015 was included. Recorded variables included age, sex, level of spinal cord injury and duration, preoperative MRI interpretation, microbiologic bone culture, smoking history, comorbidities, colostomy or urostomy, healing time, complications, length of stay, and discharge facility. RESULTS A total of 152 patients (175 flaps) were reconstructed, of which 41 patients (73 flaps) met inclusion criteria. Most patients were male (82.2%) with an average age of 50.4 years. Overall complication rate was 32.4% (n = 23) of which 34.7% (n = 8) were major. Positive and negative predictive MRI values were 84.6% and 16.7%, respectively. There were no significant differences in healing time or complication rate in those with or without osteomyelitis. Intraoperative growth was associated with decreased postoperative complications (hazard ratio = 0.361; P = 0.037). CONCLUSION Test properties of MRI for diagnosis of osteomyelitis in patients with chronic pressure ulcers have limited ability to diagnose osteomyelitis and do not aid in surgical management, but do increase health-care expense. The diagnosis of osteomyelitis by intraoperative bone cultures does not predict inferior outcomes and paradoxically may be associated with fewer postoperative complications.