ortho - chronic osteomyelitis
TRANSCRIPT
Chronic OsteomyelitisFrayna, Rajib V.
Gorospe, Paul Andrew M.Ismael, Janie-Vi V.
Liao, Jasper
OSTEOMYELITIS
Infection of bone and bone marrow
Subdivided into : Acute Subacute Chronic
In children, the long bones (such as the thigh bones) are usually affected by osteomyelitis.
In adults, the vertebrae and the pelvis are most commonly affected by osteomyelitis.
CLASSIFICATION
CHRONIC OSTEOMYELITIS
a severe, persistent, and sometimes incapacitating infection of bone and bone marrow
usually occur in adults
Chronic infection is more likely to develop in contiguous-focus than in hematogenous osteomyelitis
results when bone tissue dies as a result of the lost blood supply
relatively common as a sequelae from open fractures or gunshot wounds The presence of a foreign body makes establishment of
chronic infection.
ETIOLOGY
Inadequate treatment of acute osteomyelitis
A hematogenous type of osteomyelitis
Trauma
Iatrogenic causes such as joint replacements and the internal fixation of fractures
Compound fractures
Infection with organisms, such as Mycobacterium tuberculosis and Treponema species (syphilis)
Contiguous spread from soft tissues, as may occur with diabetic ulcers or ulcers associated with peripheral vascular disease
The specific microorganism(s) isolated from patients with bacterial osteomyelitis is often associated with the age of the patient or the clinical scenario.
Staphylococcus aureus is implicated in most cases of acute hematogenous osteomyelitis and is responsible for up to 90 percent of cases in otherwise healthy children.
Staphylococcus epidermidis, S. aureus, Pseudomonas aeruginosa, Serratia marcescens and Escherichia coli are commonly isolated in patients with chronic osteomyelitis.
Risk Factors
Recent trauma
Diabetes Mellitus
Hemodialysis Patients
IV Drug abuse
Immunocompromised Patients Altered neutrophil defense, humoral immunity and
cell-mediated immunity
HOST FACTORS THAT AFFECT WOUND HEALING
Diabetes
Use of steroids
Poor nutrition
Extensive scarring
Use of tobacco products
Cancer
Previous radiation therapy
Organ failure
Chronic lymphedema
Old age
Cardinal Signs of Chronic Osteomyelitis
Draining sinus tracts
Deformity
Instability and local signs of impaired vascularity, range of motion and neurologic status.
The incidence of deep musculoskeletal infection from open fractures has been reported to be as high as 23 percent.
Common Signs and Symptoms
Pain in the bone
Local swelling
Redness, and warmth
High fever
Nausea
An abscess at the site of infection.
Classification of Chronic Osteomyelitis
STAGE 1: Medullary Osteomyelitis
the biofilm nidus is confined to the endosteum as dense scar, infarcted marrow, dead bone, or a medullary implant. Soft-tissue involvement is usually reactive in nature and responsive to removal of the nidus and a short course of antibiotics.
STAGE 2: Superficial Osteomyelitis
the nidus is an exposed, bony surface at the base of a chronic, open wound. The medullary contents are not involved. Common examples include bone at the base of a pressure sore (decubitus) and chronic wounds associated with Papineau bone grafts.
STAGE 3: Localized Osteomyelitis
The hallmark of type III osteomyelitis is presence of a full-thickness, cortical sequestrum. The canal is involved (type I pattern), there may be a soft-tissue deficit (type II pattern), and in- dwelling hardware is commonly present. Example : an infected fracture union with plate
fixation and presence of a sequestered, butterfly fragment. To distinguish this from a type IV osteomyelitis, the involved bony segment will still be stable following a complete debridement.
STAGE 4: Diffuse Osteomyelitis
This is a permeative , through-and-through type of infection combining the characteristics of types I, II, and III osteomyelitis with the additional feature of instability intrinsically unstable rendered unstable with debridement
Diagnostic Tools
Diagnosis
based primarily on the clinical findings, with data from the initial history, physical examination and laboratory tests serving primarily as benchmarks against which treatment response is measured.
The palpation of bone in the depths of infected pedal ulcers in patients with diabetes mellitus is strongly correlated with the presence of underlying osteomyelitis (sensitivity, 66 percent; specificity, 85 percent; positive predictive value, 89 percent; negative predictive value, 56 percent).
Grayson ML, Gibbons GW, Balogh K, Levin E, Karchmer AW. Probing to bone in infected pedal ulcers. JAMA. 1995;273:721–3.
Radiologic assessment of chronic osteomyelitis is performed for the following reasons: (1) to evaluate bone involvement (eg, the extent of
active intramedullary infection or abscess superimposed on areas of necrosis, sequestrum and fibrosis)
(2) to identify soft tissue involvement (areas of cellulitis, abscess, and sinus tracts)
In osteomyelitis of the extremities, plainfilm radiography and bone scintigraphy remain the primary investigative tools
Eckman MH, Greenfield S, Mackey WC, Wong JB, Kaplan S, Sullivan L, et al. Foot infections in diabetic patients. JAMA. 1995;273:712–20.
The chronic phase of the disease is characterized by thick, irregular, sclerotic bone interspersed with radiolucencies, an elevated periosteum, and chronic draining sinuses .
Diagnostic Tools
For nuclear imaging, technetium Tc-99m methylene diphosphonate is the radiopharmaceutical agent of choice.
Tumeh SS, Tohmeh AG. Nuclear medicine techniques in septic arthritis and osteomyelitis. Rheum Dis Clin North Am. 1991;17:559–83.
The specificity of bone scintigraphy will not be high enough to confirm the diagnosis of osteomyelitis in many clinical situations.
Littenberg B, Mushlin AI. Technetium bone scanning in the diagnosis of osteomyelitis: a metaanalysis of test performance. Diagnostic Technology Assessment Consortium. J Gen Intern Med. 1992;7:158–64.
Nuclear Imaging using Tc-99m
POINT TO CONSIDER
On a bone scan, osteomyelitis often cannot be distinguished from a soft tissue infection, a neurotrophic lesion, gout, degenerative joint disease, postsurgical changes, a healing fracture, a noninfectious inflammatory reaction or a stress fracture. In many instances, a bone scan will be positive despite the absence of bone or joint abnormality.
MAGNETIC RESONANCE IMAGING
The use of MRI is expanding because of its high sensitivity and specificity as well as its ability to demonstrate associated soft tissue abnormalities.
Fauce, et.al ; Harrison’s Principles of Internal Medicine, 17th edition
MRI also provides greater spatial resolution in delineating the anatomic extension of infection.
Meyers SP, Wiener SN. Diagnosis of hematogenous pyogenic vertebral osteomyelitis by magnetic resonance imaging. Arch Intern Med. 1991;151:683–7
MRI
Ultrasound and CT Scan
Ultrasonography and computed tomographic (CT) scanning may be helpful in the evaluation of suspected osteomyelitis.
Boutin RD, Brossmann J, Sartoris DJ, Reilly D, Resnick D. Update on imaging of orthopedic infections. Orthop Clin North Am. 1998;29:41–66.
An ultrasound examination can detect fluid collections (e.g., an abscess) and surface abnormalities of bone (e.g., periostitis)
CT scan can reveal small areas of osteolysis in cortical bone, small foci of gas and minute foreign bodies.
GOLD STANDARD
Histopathologic and microbiologic examination of bone is the gold standard for diagnosing osteomyelitis. Cultures of sinus tract samples are not reliable for identifying causative organisms. Therefore, biopsy is advocated to determine the etiology of osteomyelitis.
Mackowiak PA, Jones SR, Smith JW. Diagnostic value of sinus-tract cultures in chronic osteomyelitis. JAMA. 1978;239:2772–5.
SURGICAL TREATMENT
Treatment Algorithm for Adult Chronic Osteomyelitis,2010*
Treatment Format
To justify the morbidity and risk of limb salvage, the expected outcome must offer distinct advantage(s) over an amputation or observation, alone. If treatment for cure is contraindicated or excessive, the patient is classified a C-host and offered palliation (incision/drainage, oral antibiotics, ambulatory aides, and pain medication).
Amputation is indicated when limb salvage and palliation are neither safe nor feasible.
Stage Directed Limb Salvage
STAGE 1: Medullary Osteomyelitis
requires surgical excision of the nidus through a cortical window either direct (unroofing the lesion) or indirect (reaming
through the canal) from above or below the nidus. Truncated lesions, at a diaphyseal-metaphyseal junction
(isthmus and beyond), require combined reaming and unroofing to complete the excision
Due to the limited involvement of investing soft tissues in type I lesions, the dead space remaining after debridement is usually confined to the medullary canal. A primary closure, an antibiotic depot within the canal and a short course of systemic antibiotics will, therefore, usually suffice for treatment.
STAGE 2: Superficial Osteomyelitis
preoperative planning must focus on restoration of the soft-tissue envelope
Surgical treatment begins with resection of soft tissues to viable/supple margins and the bone to the paprika sign. Paprika Sign – “bleeding bone”
Local transpositions and free flaps are the most common methods used to restore and reconstruct type II osteomyelitis.
STAGE 3: Localized Osteomyelitis
debridement commonly leads to a composite, hard, and soft-tissue deficit.
If the excision will be of such a magnitude as to threaten the mechanical stability of the remaining bony segment, the limb may be prophylactically stabilized with use of an osseous transfer , an external fixator, or stabilized in situ, following debridement, with an antibiotic depot (antibiotic-coated implant/spacers or antibiotic rods).
If osseous reconstruction is indicated or a significant dead space exists following debridement, reconstruction will usually follow a course of local antibiotic therapy
STAGE 4: Diffuse Osteomyelitis
Debridement of a type IV lesion always culminates in an unstable bony segment.
Instability, an insidious zone of injury, bone loss, and a predominantly compromised (B-host) patient population make type IV lesions the most difficult to treat.
Nearly all treatment protocols call for a staged reconstruction with the reconstruction later taking place as a clean procedure.
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