CHRONIC OSTEOMYELITIS

Osteomyelitis

Osteomyelitis is defined as an inflammation of the bone caused by an infecting organism.

The infection may be limited to a single portion of the bone or may involve the marrow, cortex, periosteum, and the surrounding soft tissue.

CLASSIFICATION

Duration of symptoms (acute, subacute, and chronic)

Mechanism of infection exogenous or hematogenous.

Based on the host response to the disease. pyogenic or nonpyogenic

When the duration of osteomyelitis is more than 3 weeks, its called ch. Osteomyelitis.

Causes-1.Trauma causing open fractures.2.Post operative.3.Osteomyelitis with chronic etiology-- TB- Brodie’s abscess.- Fungal osteomyelitis.

CHRONIC OSTEOMYELITIS

Chronic osteomyelitis is difficult to eradicate completely.

Systemic symptoms may subside, but one or more foci in the bone may contain purulent material, infected granulation tissue, or a sequestrum

PATHOLOGY

Necrosis. stage of new bone formation involucrum. with sequestrum inside, with a persistent discharging sinus. pus from bone escapes through multiple hole in involucrum

CHRONIC OSTEOMYELITIS

The hallmark of chronic osteomyelitis is infected dead bone within a compromised soft-tissue envelope.

The infected foci within the bone are surrounded by sclerotic, relatively avascular bone covered by a thickened periosteum and scarred muscle and subcutaneous tissue.

This avascular envelope of scar tissue leaves systemic antibiotics essentially ineffective.

Chronic osteomyelitis

Secondary infections are common, and sinus track cultures usually do not correlate with cultures obtained at bone biopsy.

Multiple organisms may grow from cultures taken from sinus tracks and from open biopsy specimens of surrounding soft tissue and bone.

CLINICALLY

- Pain, swelling.- Discharging sinus. - Bone thickening.- Deformity.- Joint stiffness.- Shortening of limb, - Pathological fracture.- Sinus track

malignancy.

Cierny and Mader Staging System

MedullaryEndosteal disease

TypeI Medullary Endosteal disease

II Superficial Cortical surface infected because of coverage defect

III Localized Cortical sequestrum that can be excised without compromising stability

IV Diffuse Features of I, II, and III plus mechanical instability before or after débridementl sequestrum

D/D

1.TB osteomyelitis- watery discharge. - previous h/o TB, sinus with undermined

margin with blue colour.2. Ewing's sarcoma- A primary malignant

tumor of bone, usually arising as a central tumor in long bone. (biopsy)

3. Soft tissue chronic infection. (X-ray)

Diagnosis

Clinical, Laboratory, and Imaging studies.

The “gold standard” is to obtain a biopsy specimen for histological and microbiological evaluation of the infected bone.

Diagnosis

Clinical examination

- Integrity of the skin and soft tissue -areas of tenderness -assess bone stability - neurovascular status of the limb.

Laboratory investigations

Blood countsESRCRP

Imaging studies

Plain radiographs cortical destruction periosteal reaction Sequestrum

deformity Sclerotic bone

Sinography

CT Scan

Cortical bone and surrounding soft tissues and is especially useful in identifying sequestra.

MRI

The extent of the pathological insult by showing the margins of bone and soft-tissue edema.

Well-defined rim of high signal intensity surrounding the focus of active disease seen (rim sign).

TREATMENT

Supportive treatment .Antibiotics – to prevent spread.Surgery – sequestretomy + saucerization [cannot be eradicated without surgical

intervention]

Sequestrectomy and Curettage

Sinus tracks can be injected with methylene blue 24 hours before surgery to make them easier to locate and excise.

TECHNIQUE  

•    Expose the infected area of bone and excise all sinus tracks completely.

•    Incise the indurated periosteum and elevate it 1.3 to 2.5 cm on each side.

•    Use a drill to outline a cortical window at the appropriate site and remove it with an osteotome.

•    Remove all sequestra purulent material and scarred and necrotic tissue . If sclerotic bone seals off a cavity within the medullary canalopen it into the canal in both directions to allow blood vessels to grow into the cavity.

   After removing all suspicious matter, carefully excise the overhanging edges of bone and avoid leaving a cavity or dead space. If a cavity cannot be filled by the surrounding soft tissue, a local muscle flap or a free tissue transfer can be used to obliterate the dead space.

    If there is a nonunion present with any bony instability the bone must be stabilized preferably with an Ilizarov-type external frame.

   If possible close the skin loosely over drains and ensure that no excessive skin tension is present. If closure is impossible, pack the wound open loosely or apply an antibiotic bead pouch and plan for delayed closure or skin grafting at a later time.

    Appropriate antibiotics should be used before during and after the operation.

AFTER TREATMENT

6-week course of intravenous antibiotics is given after surgical débridement

The limb is splinted until the wound has healed, and then it is protected to prevent pathological fracture

Methods described to eliminate dead space

(1) Bone grafting with primary or secondary closure

(2) Antibiotic polymethyl methacrylate (PMMA) beads as a temporary filler of the dead space before reconstruction

(3) Local muscle flaps and skin grafting with or without bone grafting

(4) Microvascular transfer of muscle, myocutaneous, osseous, and osteocutaneous flaps

(5) The use of bone transport (Ilizarov technique).

Open Bone Grafting (Papineautechnique)

STAGE I: DéBRIDEMENT

STAGE II: GRAFTING (autogenous cancellous bone grafting)

STAGE III: WOUND COVERAGE

Papineau Technique

STAGE I: DéBRIDEMENT

STAGE II: GRAFTING

STAGE III: WOUND COVERAGE

In some cases, spontaneous epithelialization

otherwise, skin grafts myocutaneous flaps muscle pedicle flaps free flaps requiring microvascular anastomosis.

COMPLICATIONS

Joint stiffness.Shortening.Muscle contracture.Pathological fracture.Sinus track malignancy.Amyloidosis.

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