CHRONIC OSTEOMYELITIS

Presenter-Dr Md NayeemuddinModerator-Dr PG SHAH

INTRODUCTION

• In pre antibiotic era mortality and morbidity following osteomyelitis was very high.

• Antimicrobials drugs have changed the course of osteomyelitis but in developing and under developed countries , where health care facilities are inadequate ,osteomyelitis remains a problem.

Reason for such a situation(4 failures).

• Failure to suspect correct diagnosis within the first 3 – 4 days of onset due to lack of a “high index of suspicion”.

• Failure to perform the simple clinical investigations which can confirm the suspicion.

• Failure to initiate properly planned therapeutic program.

• Failure to continue treatment till the disease is eliminated.

INTRODUCTION (Contd).

• Hematogenous osteomyelitis is the generic name for a whole spectrum of clinical manifestations , the cause of which is infection of bone and marrow from circulating organisms in the blood from distant source.

• The infection can be acute , subacute and chronic osteomyelitis depending on the nature , virulence and dose of the infecting organisms , the age , immune system and general condition of host.

INTRODUCTION (Contd)

• ACUTE OSTEOMYELITIS – produces the signs of systemic and local infection

• SUBACUTE OSTEOMYELITIS – does not show signs of systemic involvement though local signs are there

• CHRONIC OSTEOMYELITIS – presents with discharging sinus and recurrent infections.

PATHOLOGY

• In any infection of bone , there is an attempt at repair that ,if incomplete it results in chronic persistence of infection.

• This repair is accomplised by hyperemia of the surrounding tissue , which effects the decalcification of the bone.

• Granulation tissue forms and carries in osteoclasts n osteoblasts.

PATHOLOGY(contd).

• Necrotic cancellous bone is readily absorbed and replaced by new bone.

• Dead cortex is gradually absorbed about its surface and is detached from living bone to form a sequestrum.(this requires several months)

• SEQUESTRUM – is a piece of dead bone , surrounded by infected granulation tissue trying to “eat” the sequestrum away. It appears pale having smooth inner surface and a rough outer.

Different types of SEQUESTRA TYPE DISEASE TUBULAR PYOGENIC

RING EXTERNAL FIXATORS

BLACK ACTINOMYCOSIS

CORALLIFORM PERTHE’S DISEASE

COKE TUBERCULOSIS

SANDY TUBERCULOSIS

FEATHERY SYPHILIS

PATHOLOGY (Contd)• When SEQUESTRUM IS COMPLETE, it lies in the free cavity

and is LESS attacked by granulation tissue and is absorbed more slowly.

• Meanwhile , the surrounding living bone attempts to wall off the infection by forming a thick , dense wall , the INVOLUCRUM.

• (INVOLUCRUM is the dense sclerotic bone overlying the sequestrum).

• An involucrum usually has multiple openings , the cloacae , through which exudate , bone debris , and sequestra find exit and pass through sinus tracts to the surface.

Pathology (contd).

• CONSTANT DESTRUCTION of neighboring soft tissue leads to

THIN skin which is easily traumatised , skin epithelium grows inwards to line the sinus tract.

• In chronic osteomyelitis of long standing , multiple cavities and sequestra exist throughout the bone

• The shaft becomes thickened , irregular and deformed.

BACTERIOLOGY• STAPHLOCOCCUS AUREUS ,is the most common infecting

organism.

• Other organisms are – group A streptococci , pseudomonas aeruginosa , proteus , E.coli , staphylococcus epidermidis .

• Hemophilus influenzae – culprit in childrens below 2 years of age.

• Bacteroids.

• Salmonella in patients suffering from sickle cell anaemia.

CLINICAL PICTURE

• During the period of inactivity no symptoms are present.

• The bone is misshapen and the shin is dusky ,thin , scarred and poorly nourished.

• A break in the skin causes an ulceration that is slow to heal.

• Muscles are scarred and cause contractures of the adjacent joints.

CLINICAL PICTURE(contd)

• Pain is aching type and usually worsens in the night.

• The overlying soft tissues become swollen , edematous , warm , reddened and tender.

• As the infection progresses a sinus is formed n is drained indefinitely.

• Spontaneous closure of the sinus and subsidence of infection often occur following explusion of large fragment.

CLINICAL PICTURE(contd)

• Recurrent flare ups occurs indefinitely over a period of months and years . A sinus may drain continously.

• Recurrent toxemia over a long period will causes amyloidosis.

DIAGNOSIS

• The diagnosis is based on Clinical , Laboratory and Imaging studies.

• The “GOLD STANDARD” is to obtain a biopsy specimen for histological and microbiological evaluation of the infected bone.

CLINICAL

• Physical examination should be focused on integrity of skin and soft tissue .

• Determination of area of tenderness.

• Assessing bone stability.

• And evaluation of neuro vascular status of the limb

LABORATORY • Lab studies generally are

nonspecific and give no indication for severity of the infection.

• ESR and C- Reactive protein are elevated in most patients.

• But WBC’S elevated in only 35%.

Multiple imaging technique are available to evaluate chronic osteomyelitis ,however no technique can absolutely confirm or

exclude presence of osteomyelitis.

• Imaging should be done to confirm the diagnosis and prepare for surgery.

• Initial plain radiographs to be performed it yields valuable info .

• Signs of cortical destruction and periosteal reaction strongly suggest the diagnosis of osteomyelitis.

• Sinography can be preformed if a sinus track is present and can be valuable adjunct to surgical planning.

• Isotopic bone scanning is more useful in acute osteomyelitis than chronic osteomyelitis.

• CT provides excellent definition of cortical bone and a fair evaluation of the surrounding soft tissues and is especially useful in identifying sequestra.

• MRI provides a fairly accurate measure of pathological insult to bone and soft tissue , so it is superior to CT in soft tissue evaluation.

• MRI may reveal a well defined rim of high signal intensity surrounding the focus of active disease (RIM SIGN).

TREATMENT

• Requires a multi faceted approach.• In addition to antibiotic and surgical debridement n

reconstruction.• 1st objective is removal of dead bones(sequestrum).• 2nd objective is to find a method of obliterating any

dead space left after debridement.• 3rd objective is to obtain soft tissue coverage of

exposed bone which is a part of the objective of the obliterating dead space.

TREATMENT(contd).

• In spite of somewhat clear objectives, the actual decision making process is not always easy or clear cut.

• The real test of a surgeon’s judgement lies not only in deciding when to operate , but also how to avoid meddlesome surgery.

• Total eradication of all areas of potentially infected bone is hardly possible.

TREATMENT(contd).• Surgery for osteomyelitis consists of sequestrectomy and

resection of scarred and infected bone and soft tissue.

• Ring External fixators are generally used for soft tissue and dead space management after radical debridement.

• The GOAL of surgery is to eradicate infection by achieving a viable and vascular environment.

• Extensive debridement creates a large dead space – this is treated with ANTIBIOTIC POLYMETHYL METH ACRYLATE (PMMA) beads that fills the dead space and prevents recurrences.

TREATMENT(contd).

• The duration of post operative antibiotics is controversial .

• Traditionally , a 6 week course of intravenous antibiotics is prescribed after surgical debridement.

TREATMENT(contd).• The methods to eliminate the dead space are –

1. Bone grafting with primary and secondary closure.2. Use of PMMA as a temporary filler of dead space.3. Local muscle flaps and skin grafting with or without

bone grafting.4. Microvascular transfer of muscle , osseous flaps.5. The use of bone transport (ILIZAROV TECHNIQUE).

TREATMENT(contd).

• SEQUESTRECTOMY AND CURETTAGE FOR CHRONIC OSTEOMYELITIS

SEQUESTRECTOMY means removal of the sequestrum .if it lies within the medullary cavity , a window is made in the overlying involucrum and the sequestrum removed .

One must wait for adequate involucrum formation before performing sequestrectomy.

SEQUESTRECTOMY AND CURETTAGE FOR CHRONIC OSTEOMYELITIS.

• Sequestrectomy and curettage require more time to perform and result in considerably more blood loss than an inexperienced surgeon would anticipate.

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

OPEN BONE GRAFTING

• Papineau et al described an open bone grafting technique for the treatment of chronic osteomyelitis .

• This procedure relies on the formation of healthy granulation tissue in a bed of bone graft that will become rapidly vascularised.

• The granulation tissue resists infection and is allowed to adequately drained.

• This technique is used when free flaps or soft tissue transfer options are limited because of anatomic location .

OPEN BONE GRAFTING (contd)

• Archdeacon and messerschmitt described a modification of the papineau technique using a vaccum assisted closure (VAC).

• VAC helps in decreasing the edema and for the closure of soft tissue dead space.

• It also promotes the formation of granulation tissue.

POLYMETHYLMETHACRYLATE ANTIBIOTIC BEAD CHAINS

• IT IS COMMONLY USED.

• Studies have shown that the local concentrations achieved are 200 times more than intravenous.

• High concentration can be achieved by primary closure of the wound.

• Short term (10 days), long term(80days) , permanent implantation of PMMA beads is possible.

BIODEGRADABLE ANTIBIOTIC DELIVERY SYSTEM

• It offers a significant advantage over PMMA in that a second procedure is not required to remove the implant.

• It is useful when bone stability is not an issue and soft tissue coverage is adequate.

• Many manufacturers produce a variety of bioabsorbable substrates(calcium sulfate or calcium phosphate)that can be mixed with antibiotics like vancomycin and tobramycin).

• Its still under study.

SOFT TISSUE TRANSFER

• It is mainly done to fill dead space which is left behind after extensive debridement.

• Success rate reported in the literature ranges from 66% to 100%.

• For eg chronic osteomyelitis of tibia a local muscle graft from gastrocnemius or soleus is used for transfer.

ILIZAROV TECHNIQUE

• This technique allows radical resection of the infected bone

• A corticotomy is performed through the normal bone proximal and distal to the area of the disease.

• Disadvantage is – long time to achieve solid unioun and high chances of infections.

• The treatment of segmental defects of upto 13cms can be achieved.

ADJUNCTIVE THERAPIES

• Hyperbaric Oxygen is not reliably effective but is used as more traditional methods of treatment.

• Bone morphogenic proteins (BMPs) and even Platelet Rich Plasmas (PRPs) have been advocated as it has the ability to acccelerate or enchance osteogenesis.

COMPLICATIONS• An acute exacerbation of the infections occurs commonly.• Growth Abnormalities : shortening –if growth plate is damaged. Lengthening – coz of increased vasularity of the growth plate due to near by osteomyelitis.

• Pathologic fracture .

• Joint stiffness – may occur because of scarring of soft tissues around the joint.

• Sinus tract malignancy – rare complication (squamous cell carcinoma)

• Muscle contracture.

• Epithelioma.

• Amyloidosis.