Osteo/ORN/MRONJ Flashcards
MRONJ/ORN/Osto
Radiographic presentation of these diseases
- Abnormal bone architecture
- Increase radiopacity of the cortical bone
- Diffuse sclerosis in the bone marrow
- Sequestrum
Osteomyelitis
- Inflammatory process of the bone marrow that progress to the cortical bone and the periosteum.
Classification of osteomyelitis
- The Zurich classification system is based on clinical presentation radiographic appearance and the natural course of the disease
- Acute less than a month
- Primary chronic greater than 1 month
- Secondary
- suppurative (pus forming), or non-suppurative.
- Odontogenic mixed flora (primarily alpha- hemolytic Streptococci vs. Staphylococcus aureus seen in the axial skeleton.
Pathophysiology of osteomyelitis
Microorganisms: Access to the bone marrow
Infection of the bone marrow with increase in the intramedullary pressure
Micro vessels thrombosis
Necrosis of the Osteocyte and subsequently the bone
- MRI in acute osteomyelitis shows abnormal low T1 bone marrow signal
- CT scan can show the extent of lytic bone, keeping in mind 30% demineralization is required to appreciate changes.
- Technetium-99, although non-specific, will aid in identifying areas of higher blood flow and osteoblastic activity. As early as 3 days
- Gallium-67 aids in ruling out osteomyelitis from malignancy and trauma. Gallium-67 identifies inflammatory changes, as it binds to granulocytes.
ORN
- chronic and progressive disease that is defined as exposed, non-healed bone over a three-month period with no evidence of residual or recurrent cancer caused by radiation therapy to the head and neck region
- About 9% of patients who received more than 60Gy
- Can develop spontaneously or after insulting trauma
Classification of ORN
Marx staging system
* Based on the response to HBO
Stage 1: Resolution of the ORN after maximum of 40 sessions of HBO
Stage 2: Resolution of the ORN after maximum of 40 sessions of HBO + Sequestrectomy
Stage 3: Failed stage Il or ORN extends to the inferior border of the mandible or
Osteocutaneous fistula
Notani Staging
Stage 1: confined to the alveolar bone
Stage 2: Confined to the mandible above the level of the IAN canal
Stage 3: Extending deep to the level of the IAN canal, or pathologic fracture or fistula
Pathophysiology of ORN
Triple Hs theory
Hypoxia
Hypovascualr
Hypocellular
- ask for bone mapping , will tell you the radiation field and the intensity as well
MRONJ
- Exposed non-healing bone in the mandible or maxilla that persists for more than eight weeks in a person who received a systemic drug known to cause osteonecrosis but who has not received local radiation to the jaws.
- Patients at risk include DM, immunosuppressed, autoimmune disease, smokers.
Pathophysiology of MRONJ
1- Bone remodeling inhibition
2- Infection and inflammation
3- Inhibition of angiogenesis
4- Immune system dysfunction
5- Genetic predisposition
* Single-nucleotide Polymorphism
(SNP) found to be associated with the development of MRONJ P450 CYP2C8
Staging of MRONJ AAOMS system
At risk:
* Patient treated with IV or PO antiresorptive therapy
* Asymptomatic
* No radiographic changes
Stage O
* No evidence of exposed bone
* Non specific symptoms:
- Dull aching jaw pain
- Maxillary sinus pain
- Neurosensory disturbance
* Radiographic changes:
- Osteosclerosis
- Changes in the trabecular pattern of the bone
- Thickenings of the lamina dura
- Close follow up
Stage 1
* Exposed bone
* Fistula that can be probed to the bone.
* Asymptomatic
* Radiographic changes are similar to stage 0 disease
Stage 2
* Exposed bone
* Fistula that can be probed to the bone.
* Symptoms with evidence of active infection or inflammation
* Radiographic changes are similar to stage 0 disease
Stage 3
* Exposed necrotic bone extends beyond the boundary of the the alveolar bone
* Pathologic fracture
* Extraoral fistula
* Oro-antral/nasal communication
* Osteolysis extending to the inferior boarder of the mandible or th maxillary sinus floor
What is PET scan
Radiographic modulatiy using deoxy-glucose (FDG) as radiolabeled radiotracer. Any tissue with high metabolic rate has high standard uptake value (SUV) of FDG will lights up on PET scans.
