ortho - chronic osteomyelitis

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.

THANK YOU.