Bisphosphonate-related Osteonecrosis of the Jaw

 

(BON) (BRONJ)

 

 

General Considerations

• Bisphosphonates are commonly prescribed for the treatment and prevention of
  • Osteoporosis (e.g. alendronate, risendronate, ibandronate)
• Osteolytic lesions in metastatic bone tumors (e.g. breast, prostate, multiple myeloma) (e.g. zoledronate, pamidronate)
• Hypercalcemia associated with malignancy
• Bind and inhibit osteoclastic activity
• There has been an association described between bisphosphonates, usually in higher doses in cancer patients, and avascular necrosis, especially of the mandible
  • Incidence has been most strongly correlated with pamidronate (Aredia) and zoledronic acid (Zometa)
• Many develop after tooth extraction which may serve as a trigger
• Latency of 5-36 months after therapy before osteonecrosis occurs
• More common with IV administration of drug than oral

Clinical Findings

• Exposed, non-vital bone
• Pain
• Swelling
• Trismus

Imaging Findings

• Confined to mandible (majority) and maxilla
• Mixed lytic and sclerotic lesion of the jaw
• Sequestration
• Pathologic fracture
• Periosteal reaction
• MRI-low T1 and T2 with exposed bone and low T1 and high T2 in unexposed bone

Differential Diagnosis

• Metastatic bone lesion
• Osteomyelitis

Treatment

• Difficult
• Discontinue bisphosphonate therapy
• Avoid dental extractions
• Medical therapy may include antibiotics used locally and systemically
• Surgical curettage has been used
• Chemical debridement with antiseptic irrigations
• Long-term antibiotic treatment may be useful

Complications

• Pathologic fracture
• Osteomyelitis
• Draining fistulae