Osteomyelitis management: More art than science?

Abstract

Over the past 40 years, several authoritative reviews on osteomyelitis have been published in The New England Journal of Medicine (1–4). They have provided commentary on definition, pathogenesis, diagnosis and treatment. Simplistically, acute osteomyelitis is a newly recognized bone infection, and chronic osteomyelitis is the relapse of a previously treated or untreated infection (4). One hallmark of chronic osteomyelitis is necrotic bone, resulting from impaired blood flow related to raised intraosseous pressure (4). There are several staging systems for osteomyelitis to help guide therapeutic decisions and allow for comparisons across studies. The oldest of these is Waldvogel's staging system, which classifies osteomyelitis as hematogenous or contiguous, with contiguous further subdivided into the presence or absence of vascular insufficiency (5). This is probably the classification system most familiar to infectious diseases physicians, and it provides a framework for treatment recommendations in Mandell's Principles and Practice of Infectious Diseases (6) and The Sanford Guide to Antimicrobial Therapy 2006 (7). Another commonly applied staging system for long-bone osteomyelitis is the Cierny-Mader staging system, which is based on anatomy, physiological status of the host (normal or compromised), and systemic or local factors that affect immune surveillance, metabolism and bone vascularity (5,8). While the Cierny-Mader staging system is more detailed than the Waldvogel staging system, there are similarities in the anatomical stratification, with anatomical stage 1 (medullary) correlating with hematogenous, and anatomical stages two to four (superficial, localized and diffuse) related to contiguous, although the Cierny-Mader system better describes the extent of disease and surgical management. Integrating the anatomical and host factors in the Cierny-Mader system creates 12 potential clinical stages (9). Most cases of osteomyelitis in adults are contiguous, and the usual antecedent factors are trauma, surgery or pressure ulcers. Hematogenous osteomyelitis, when it occurs in adults, involves primarily the axial skeleton (10). Most of the other staging systems relate to anatomical and pathological features of the osteomyelitis, such as presence of sinuses, fracture (united or nonunion), duration of drainage and degree of bone loss (8). Clearly, these staging systems would be more familiar to orthopedic surgeons.