The article:  What is Osteomyelomyelitis? What Causes Osteomyelitis?” in Medical News Today: 10 Feb 2010-0:00PST

Dr. Cierny comments:

TYPES OF OSTEOMYELITIS: ‘Acute’,’ sub-acute’ and ‘chronic’ are time-related terms that parallel the fundamental principles and mechanisms  inherent to wound colonization by microorganisms.  Early in the course of infection, microorganisms are mobile (plankonic) and vulnerable to antibiotics and host defenses.   If the fracture is live and stable, the infection may resolve following adequate wound decompression, antimicrobials and the elimination of dead space (the acute wound).  After 2-3 weeks,  reactions between surface macromolecules begin forming at pathogen-substrate interfaces (sub-acute), resulting in a resilient “microzone’ of attachment in 4-6weeks that is precursor to a microbial-based, mucopolysaccharide “slime” that encompasses the entire colony.   Within the bio-slime (biofilm) microbial nutrition and growth are enhanced, protected from host defenses and the penetration /effects of antimicrobials.  The result is a profound compromise to the host: wound healing and fracture repair are impaired due to toxins produced by the pathogens and the by-products of host efforts to unsuccessfully destroy the biofilm colony. Curative treatment of such a biofilm-infection (chronic /refractory) requires both anti-microbial therapy and surgical removal of the entire biofilm burden.

WHAT ARE THE SIGNS AND SYMPTOMS OF OSTEOMYELITIS? See: http://www.osteomyelitis.com/html/osteomyelitis.html

WHAT ARE THE RISK FACTORS FOR OSTEOMYELITIS? Open fractures create “the perfect storm” for infection to complicate injury:  the initial wound is contaminated and injury to soft tissues potentiates an on going exposure to pathogens; surgical implants and dead bone fragments grant ‘safe-haven’ to proliferating microbes; ischemia, dead space and foreign bodies impede local immunity and the delivery of antibiotics; shock, injury and pre-existing health conditions compromise the host response.   The goals of treatment are three-fold: timely intervention; creation/maintenance of a clean, manageable wound; adequate and durable fracture fixation.

Surgical Site Infections (infection following elective surgery) are more common in compromised hosts,( ), long procedures (SSI) and operations where in a large surgical implant is used (substrat surfaces; see above).  OSTEOMYELITIS: CIERNY/MADER HOST STATUS  OSTEOMYELITIS: CIERNY/MADER CLASSIFICATION SYSTEM 

DIAGNOSIS OF OSTEOMYELITIS:   MALNUTRITION;   WHAT BLOOD TESTS ARE USED TO DIAGNOSE OSTEOMYELITIS?    DO POSITIVE CULTURES ALWAYS MEAN A BONE INFECTION IS PRESENT?   WHEN DO I NEED A NUCLEAR SCAN?

TYPES OF BONE INFECTIONS:   There are really only three etiologic categories of bone infection, not five:  hematogenous (blood-born) osteomyelitis;  contiguous-focus osteomyelitis;  and post-traumatic osteomyelitis.  Osteomyelitis due to vascular insufficiency is a form of contiguous focus infection since the lack of oxygen leads to breakdown of the integument (skin), ulceration and eventual exposure ( and contamination) of the underlying bone (a contiguous focus).  Ischemic compromise can  occur in patients with peripheral vascular disease, disruption of major bood vessels, diabetes (foot ulcers) and patients developing bed (decubitus) ulcers.

The categorization of bone infection into etiologic types,  however, does not help with establishing a treatment strategy or prognosis.  To do this, the chronology (see above), patient’s health and anatomic localization of the infection (in the bone itself) must be brought together into a staging system similar to those used for various forms of cancer.    For example, vertebral osteomyelitis is a regional localization of infection (the spine) as opposed to an anatomic localization (configuration) of the disease in the spinal bone (s) itself.  Spine infections occur following: blood-born contamination (hematogenous) to the marrow part of the bone or to the disc between the vertebral bodies;  as a contiguous focus infection (sacral decubitus ulcers); or following trauma (ie; post-operative, surgical site infections ).   Treatment will depend on the etiology, the timing (acute, subacute, chronic) and the extent to which the infection involves the bone (on the surface, in the marrow, fracture with instability, etc.).  That is why the CIERNY/MADER Clinical Staging System (1985)  is now accepted internationally as the gold standard for classifying bone infection in adults (all types, all etiologies, all locations) as it articulates the natural history of the disease with treatment and outcomes.