Evaluation of the predisposing factors and involved outcome of surgical treatment in bisphosphonate-related osteonecrosis of the jaw cases including bone biopsies

Abstract

Objectives: This study examined the statistical relevance of whether the systemic predisposing factors affect the prognosis of surgical treatment of bisphosphonate-related osteonecrosis of the jaw (BRONJ). All cases had undergone bone biopsies to determine the characteristics of the mechanisms of BRONJ by optical microscopy.

Materials and methods: The data included 54 BRONJ cases who underwent surgery and in whom bone biopsies were performed. The results of surgery were evaluated and the results were classified into 3 categories: normal recovery, delayed recovery, and recurrence after surgery. The medical history, such as diabetes mellitus, medication of steroids, malignancies on other sites was investigated for an evaluation of the systemic predisposing factors in relation to the prognosis. The three factors involved with the medication of bisphosphonate (BP) were the medication route, medication period, and drug holiday of BP before surgery. The serum C-terminal cross-linking telopeptide (CTX) value and presence of microorganism colony in bone biopsy specimens were also checked. Statistical analysis was then carried out to determine the relationship between these factors and the results of surgery.

Results: The group of patients suffering from diabetes and on steroids tended to show poorer results after surgery. Parenteral medication of BP made the patients have a poorer prognosis after surgery than oral medication. In contrast, the medication period and drug holiday of BP before surgery did not have significance with the results of surgery nor did the serum CTX value and presence of microorganism colony. Necrotic bone specimens in this study typically showed disappearing new bone formation around the osteocytic lacunae and destroyed Howship's lacunae.

Conclusion: Although many variables exist, this study could in part, predict the prognosis of surgical treatment of BRONJ by taking the patient's medical history.

Keywords: Bisphosphonate; Jaw diseases; Osteonecrosis.

Fig. 1. Distribution of surgical treatment results.

Fig. 2. Classification of systemic predisposing factors (medical and medication history). (DM: diabetes mellitus)

Fig. 3. A. Scoring system 1 calculated by adding all systemic predisposing factors. B. Scoring system 2 quotated from MUCONNS (Modified University of Connecticut Osteonecrosis Numerical Scale).

Fig. 4. A. Features about necrotic bone from biopsy specimen. The presence of cell components and blood vessels cannot be found and the formation of the new bones around the osteocystic lacunae are destroyed (black arrow). The boundaries adjacent to the necrotic bone sites are not smooth and show rugged feature in wavy aspects which is considered from loss of Howship's lacunae (arrowhead), and there is microorganism colony around the necrotic bone (white arrow). B. Condition around soft tissue nearby the necrotic bone. It shows typical forms of granulation tissue which include distribution of inflammatory cells and fibrosis (black arrows). Although this specimen was collected a little far from the necrotic bone, we can find microorganism colony (white arrow), and there are also bone fragments considered broken down from necrotic bone (arrowhead).

Fig. 5. A. Microorganism colony commonly appears not a capsular but a filamentous shape from each different stain (A: Gram staining, ×200, B: GMS staining, ×200, C: dPAS staining, ×200).