Pathologic fractures in bisphosphonate-related osteonecrosis of the jaw-review of the literature and review of our own cases

Spontaneous Recovery of Pathological Fracture Caused by Medication-Related Osteonecrosis of the Jaw

Pathological fracture is one of the most serious complications in medication-related osteonecrosis of the jaw (MRONJ). This case is a report of an 87-year-old woman who had been diagnosed with pathological fracture due to MRONJ. The authors performed minimally invasive and conservative treatment, such as intraoral dressing, antibiotic therapy, and simple debridement, for patients with pathologic fractures due to MRONJ. After 1 year, the inflammatory symptoms disappeared and pathological fractures spontaneously recovered.

A Case Report of Oral Bisphosphonate Treatment for Osteoporosis Leading to Atypical Femoral Fracture and Pathologic Mandibular Fracture

BACKGROUND Bisphosphonates inhibit bone resorption in patients with postmenopausal osteoporosis and reduce osteoporotic fracture incidence. Medication-related osteonecrosis of the jaws (MRONJ) and atypical femoral fractures (AFF) are both rare but serious adverse effects of anti-resorptive drugs (ARD) such as bisphosphonates. The most advanced form of MRONJ is termed stage 3 and can lead to severe local sequelae like pathologic mandibular fractures (PMF). This study reports a case of MRONJ-related PMF and AFF with osteomyelitis secondary to bisphosphonate treatment for osteoporosis. CASE REPORT A 63-year-old white woman was diagnosed with PMF related to MRONJ stage 3 during treatment of an AFF with osteomyelitis. She had been treated for postmenopausal osteoporosis with 70 mg of alendronate weekly for 2 years. The PMF was treated by stable internal fixation combined with debridement and sequestrectomy, but further debridement was required and 2 mandibular implants were then removed. Postoperative recovery was uneventful and the mandibular infection was controlled after the second surgery. Three weeks later, she was discharged from the hospital, instructed to discontinue the use of alendronate, and referred for 30 sessions of hyperbaric oxygen therapy. At the 3-year follow-up, the PMF was completely healed without signs of mandibular infection or bone exposure. CONCLUSIONS This report raises awareness of both MRONJ and AFF as possible adverse effects of short-term bisphosphonate therapy for postmenopausal osteoporosis, and highlights the importance of dental and orthopedic follow-ups. It is crucial to emphasize the need for early diagnosis and treatment to prevent MRONJ progression to PMF.

The Role of Bone Grafts in Preventing Medication-Related Osteonecrosis of the Jaw: Histomorphometric, Immunohistochemical, and Clinical Evaluation in Animal Model

Objective

To evaluate the effects of inorganic bovine bone graft (Lumina Bone, Criteria, Brazil) and beta-tricalcium phosphate (β-TCP) graft (ChronOS, Synthes, Brazil) in rats with the risk of developing post-extraction medication-related osteonecrosis of the jaw (MRONJ).

Methods

Eighteen male Wistar rats weighing 350 to 450 g were induced to develop MRONJ using zoledronic acid for 5 weeks. In the sixth week, the right maxillary first molar was extracted. The animals in Group I (G1) did not receive bone grafts after tooth extraction, while Group II (G2) animals received inorganic bovine bone grafts, and Group III (G3) animals received beta-tricalcium phosphate (β-TCP) grafts. Clinical evaluation and histomorphometric and immunohistochemical analyses were performed. ANOVA and Tukey's statistical tests were used and a level of significance was considered to be 5%.

Results

In the clinical evaluation, animals from G2 and G3 did not present clinical manifestations of osteonecrosis, unlike the control group (G1) animals, which presented necrotic bone tissue exposure in all samples. In the histomorphometric evaluation, animals in G3 showed greater formation of bone tissue (66%) and less formation of bone lacuna (18%) than animals in G1 (58%/32%) and in G2 (59%/27%) (P < 0.05). Moderate (++) immunostaining was observed in G2 and G3 for RANKL, TRAP, and OC, while G1 showed moderate (++) labeling for OC and mild (+) immunostaining for TRAP and RANKL.

Conclusions

Greater formation of bone tissue and fewer bone lacunae were found in animals treated with β-TCP. In clinical evaluation, bone graft groups presented with the clinical manifestation of MRONJ and showed higher intensity of immunostaining for TRAP and RANKL. Despite the limitations of experimental animal studies, the results of this work may assist in the development of future clinical research for the prevention of MRONJ.

Vascularised periosteal free flap reconstruction for medication-related osteonecrosis of the jaw: a case series

Introduction: The standard of care for medication-related osteonecrosis of the jaw (MRONJ) involves anti-biotics and local debridement to promote tissue healing over exposed bone. We compare outcomes for patients with advanced MRONJ managed with vascularised periosteal radial forearm free flap (RFFF) ver-sus local nasolabial flap and conservative dental measures. Methods: A retrospective case series of patients presenting to the Alfred Hospital for evaluation and man-agement of stage II or above MRONJ between 1 January 2014 and 30 June 2018. The hospital database was searched And a medical record review performed. Results of pre- and post-treatment imaging were ana-lysed bya single senior radiologist blinded to treatment modality . Asymptomatic wound closure, radio-logical evidence of disease cessation and patient satisfaction at six months post-treatment according to treatment type were assessed. Results: Of the ten patients included in the study, four received dental measures, three received local na-solabial flap and three received RFFF flap. All flap reconstruction (6/6) showed asymptomatic wound clo-sure and patient satisfaction at six months follow-up compared to patients managed with dental measures (1/4). All RFFF patients (3/3) showed increased bone deposition radiologically at six months compared to the dental group who showed a mixed (3/4) picture or worsened (1/4) picture. Nasolabial flap patients showed a mixed (2/3) or improved radiological picture (1/3). Conclusion: MRONJ is a relapsing disease. Preliminary evidence suggests that radical debridement with local nasolabial flap or RFFF reconstruction for advanced MRONJ is more effective at halting the disease and alleviating morbidity than conservative dental measures alone.

Delayed Diagnosis of Unilateral Mandibular Condylar Fracture in a Posterior Edentulous Patient

Background

Fractures of the mandible are common in elderly patients, and among them, condylar fractures are the most frequent type. A change in occlusion is the most common physical finding in patients with fractures of the mandible. Therefore, it is challenging to identify mandibular fractures in posterior edentulous patients due to the lack of posterior occlusal contacts. It is crucial to do radiological investigations in such patients to exclude fractures. Case Presentation. This article describes a case of delayed diagnosis of a unilateral mandibular condylar fracture for a week's duration and treating the condition as temporomandibular pathology in a posterior edentulous, 52-year-old patient.

Conclusion

This clinical case highlights the importance of radiological investigations and occlusal analysis for early diagnosis of condylar fractures, particularly in posterior edentulous patients, lacking posterior occlusal contacts.

Retrospective evaluation of pathologic fractures in medication related osteonecrosis of the jaw

The aim of this study was to focus on the MRONJ-related pathologic fractures, their incidence, and to analyze possible causative factors for their occurrence. Pathologic fracture in patients suffering frm MRONJ were identified, examined in detail, and the patient characteristics were evaluated. In 116 patients (73 female and 43 male; mean age 62.08 ± 13.6 years), pathologic fracture incidence was found to be 4.31%. Zoledronic acid was the most commonly used anti-resorptive drug (77.8%). Median antiresorptive usage was 24 months. Five patients had pathologic fractures in the mandible. Four fracture patients had metastatic prostate cancer, and one had metastatic renal cell cancer. This case series study can provide clinical insight into which factors are associated with pathologic fractures. Cancer type, medical comorbidities, additive toxicity of the combination of antiresorptive and antiangiogenic drugs, specific pathogens, and dento-alveolar surgical procedures may be some of the important factors that need to be considered. Since MRONJ-related pathologic fracture management can be complicated, it may be good to focus on the causative factors and prevent occurrence with regular follow-up as often as possible in line with these factors.

The Use of Photodynamic Therapy on Medication-Related Osteonecrosis of the Jaws: Animal Study

Background/Aim: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) was first introduced in 2003 and its scope was expanded by the name medication-related osteonecrosis of the jaw (MRONJ), since 2014. This study aimed to evaluate the effects of photodynamic therapy (FDT) on tissue samples by histopathological and histomorphometric examination and serum TRACP-5b (Tartrateresistant acid phosphatase-5b) measurement in rats.

Material and Methods: 24 Sprague-Dawley male rats were divided into 3 groups comprising 8 animals. Zoledronic acid was administered to groups 1 and 2 and 0.9% sodium chloride was administered to group 3 intraperitoneally. After the injections were completed, dental extractions were performed. Photodynamic therapy was applied to group 2, three times a weekfor the two weeks after the extraction. In the 16th week, sacrification was performed. Rats were undergone histopathologic and histomorphometric evaluations.

Results: Photodynamic therapy has led to a decrease in epithelial opening and inflammation and an increase in the formation of new bone. Serum TRACP-5b values were shown to decrease significantly in the presence of osteonecrosis.

Conclusions: PDT was shown to be useful in reducing MRONJ risk in rats. As a serum biomarker, Serum TRACP-5b could be a valuable marker. Additional studies should confirm the findings.

Cardiovascular Calcification in Chronic Kidney Disease-Therapeutic Opportunities

Patients with chronic kidney disease (CKD) are highly susceptible to cardiovascular (CV) complications, thus suffering from clinical manifestations such as heart failure and stroke. CV calcification greatly contributes to the increased CV risk in CKD patients. However, no clinically viable therapies towards treatment and prevention of CV calcification or early biomarkers have been approved to date, which is largely attributed to the asymptomatic progression of calcification and the dearth of high-resolution imaging techniques to detect early calcification prior to the 'point of no return'. Clearly, new intervention and management strategies are essential to reduce CV risk factors in CKD patients. In experimental rodent models, novel promising therapeutic interventions demonstrate decreased CKD-induced calcification and prevent CV complications. Potential diagnostic markers such as the serum T50 assay, which demonstrates an association of serum calcification propensity with all-cause mortality and CV death in CKD patients, have been developed. This review provides an overview of the latest observations and evaluates the potential of these new interventions in relation to CV calcification in CKD patients. To this end, potential therapeutics have been analyzed, and their properties compared via experimental rodent models, human clinical trials, and meta-analyses.

Medication-related osteonecrosis of the jaw. Implant presence-triggered osteonecrosis: Case series and literature review

PURPOSE

The aim of this study was to review the characteristics of 'implant presence-triggered osteonecrosis' (IPTO) in the literature and identify possible differences between IPTOs and 'implant surgery-triggered osteonecrosis' (ISTO).

MATERIALS AND METHODS

Reviews using PubMed and the Cochrane Database of Systematic Reviews were performed from 2009-2018; the focus was on medication-related osteonecrosis of the jaw (MRONJ) and dental implants. In addition, the hospital records of all patients presented in our department with IPTO were retrospectively reviewed. In both studies, the following data were collected: the number of patients with ISTO or IPTO, age, gender, location, stage of MRONJ, number of implants involved in MRONJ, the elapsed time between the placement of the implants and the development of MRONJ, applied treatment and the presence of mandibular fractures and progress.

RESULTS

The literature review provided 111 articles. Nine of the articles were selected for bibliographic review. The number of osteonecrosis cases was significantly higher in the IPTO group (74 cases) compared with the ISTO group (27 cases). The duration of the anti-resorptive treatment (oral and intravenous) was also longer in the IPTO group. In our centre, seven patients with IPTO were chosen; however, no patients with ISTO were selected. The significant differences between the patients in our series and the information collected in the literature for the IPTO group were the time of ingestion of alendronate, the elapsed time from the placement of the implants to the development of the MRONJ and the number of implants linked to the development of a complication.

CONCLUSIONS

The use of antiresorptives causes osteonecrosis in patients with implants that are subjected to functional loading, and this occurs at a higher frequency than what is observed after implant placement surgery.

Further development of the MRONJ minipig large animal model

Medication-related osteonecrosis of the jaw (MRONJ) is a rare but serious and potentially severe side effect of antiresorptive therapy with bisphosphonates or denosumab. Recently, a large animal minipig MRONJ model was introduced which led to early necrotic lesions in the majority of extraction sites after bisphosphonate administration. The aim of this project was to modify the preoperative cumulative bisphosphonate dose (zoledronate) and hereby firstly to demonstrate the reliability and reproducibility of the established model. Secondly, the MRONJ lesions should be carefully investigated using clinical and μCT as well as detailed histological analyses. Twelve 1.5-year-old Göttingen minipigs were divided into three groups. In group 1 (n = 3) minipigs received weekly doses of zoledronate intravenously (0.05 mg/kg bodyweight) for 20 weeks. No interventions were performed. In group 2 (n = 6) animals received the identical zoledronate dosage as animals in group 1 and tooth extractions of two premolars (PM 2 and 4) in each jaw (maxilla and mandible) were performed after 12 weeks. Group 3 (n = 3) served as tooth extraction only control (no zoledronate administrations). The jaw-bones were subjected to detailed macroscopic, radiological and histological investigations. All extraction sites (24/24) in animals of group 2 showed clinical, radiological and histological signs of MRONJ (mainly stage II), whereas no bone necrosis was found in group 3. Animals of group 1 and group 2 showed further MRONJ lesions in areas where infections (periodontitis) were present. This is the first large animal model to show a 100% incidence of MRONJ at all extraction sites in bisphosphonate pretreated animals (group 2). In addition, in this preclinical model for MRONJ it is shown that tooth extractions are not mandatory for a MRONJ manifestation. MRONJ also developed in areas of gingival or periodontal infections.

Deep head and neck infection causing pathological fracture of the mandibular condyle

We report an unusual case of a 46-year-old male with a severe deep head and neck infection after extraction of two mandibular molars that led to a potentially life-threatening condition and caused pathological fracture of the mandibular condyle. This is the first published spontaneous pathological fracture of the mandibular condyle caused by an infection spread from a lower molar tooth. Based on CT scan we discuss the pathways of infection of odontogenic origin and the reflections of treatment. This case report illustrates an unusual presentation of a spontaneous pathological condylar fracture caused by a severe life-threatening infection after tooth extraction. It details the examination and management of the patient and reflections about the treatment.

Spontaneous fractures of the mandible concept & treatment strategy

Background

Spontaneous fractures of the mandible dispose a surgical challenge in comparisons to fractures caused by trauma due to several complicating factors. Additionally: controversies exist concerning the terminology of the field.

Material and Methods

We conducted a retrospective study of all patients with mandibular fractures, with exclusion of fractures of the coronoid process and the alveolar process, treated at the Department of Oral and Maxillofacial Surgery, Aalborg University Hospital, Denmark between February 2003 and February 2013. Data collected from the medical records included sex, age, cause of fracture, site of fracture, and treatment.

Results

We identified 517 patients with 684 mandible fractures. Twenty-five of these were spontaneous fractures and 659 fractures were of traumatic origin. Condylar fractures rarely occur spontaneously, but constitute the majority of the traumatic fractures. Excluding these fractures from the analysis, we found a non-surgical approach in 14 of 24 (58%) of the spontaneous fractures and 110 of 376 (29%) of the traumatic fractures. This was statistically significant.

Conclusions

We found a statistical significant difference in favor of non-surgical approach in spontaneous fractures and we discussed the treatment challenges of these fractures. We addressed the terminological controversies regarding pathological fractures, and suggested the term spontaneous fractures denoting a fracture occurring during normal jaw function being either pathological or non-pathological.

Key words:Mandibular fractures, spontaneous fractures, pathological fractures, traumatic fractures, treatment.

Photodynamic Inactivation of Actinomyces naeslundii in Comparison With Chlorhexidine and Polyhexanide--A New Approach for Antiseptic Treatment of Medication-Related Osteonecrosis of the Jaw?

PURPOSE

Local antimicrobial therapy is a fundamental principle in the treatment of lesions of medication-related osteonecrosis of the jaw. Antimicrobial photodynamic therapy (aPDT) as a local application for the treatment of microbial infections has become more widely used in recent years. In the mouth, the bone surface is in constant contact with saliva and thus cannot be kept sterile, making the development of strategies for disinfection even more important. Different methods currently in use include local rinses with chlorhexidine (CHX), polyhexanide (PHX), or aPDT. This study compared the efficiency of these 3 methods.

MATERIALS AND METHODS

The in vitro activity of 3 different agents against slowly growing Actinomyces naeslundii isolated from a patient with osteonecrosis was evaluated. PHX 0.04% solution, CHX 0.12% solution, and methylene blue (MB) based dye with a laser light of 660-nm wavelength (aPDT) were compared.

RESULTS

The decrease in colony-forming units by each method was measured using an in vitro killing assay based on a water-exposed surface in a well plate. MB dye with laser (10 seconds) decreased the bacterial load by more than 4 orders of magnitude and was superior to PHX and CHX exposure for 60 seconds.

CONCLUSION

Laser exposure alone and MB dye exposure alone decreased bacterial loads slightly, but less efficiently than 60-second exposure to PHX or CHX. The most effective means of decreasing colony-forming units was achieved by a combination of laser light and dye, which also can be used clinically.

Efficacy of systemic bisphosphonate delivery on osseointegration of implants under osteoporotic conditions: lessons from animal studies

BACKGROUND

The aim was to systematically review the role of systemic bisphosphonate (BP) delivery on osseointegration of implants under osteoporotic conditions.

METHODS

The addressed focused question was "Does systemic BP delivery enhance osseointegration of implants under osteoporotic conditions?" PubMed/MEDLINE and Google-Scholar databases were searched from 1994 up to and including December 2013 using different combinations of the following keywords: "bone to implant contact", "implant", "bisphosphonate", "osseointegration" and "osteoporosis". Review articles, case-reports, commentaries, letters to the Editor, unpublished articles and articles published in languages other than English were excluded.

RESULTS

Fifteen animal studies fulfilled our eligibility criteria. Osteoporotic conditions were induced via bilateral ovariectomy (OVX). BPs used in the studies were ibandronate, zoledronic acid and alendronate. Results from 12 studies showed that systemic BP delivery significantly increased bone volume and bone-to-implant contact under osteoporotic conditions. Two studies reported no significant difference in osseointegration among OVX animals with and without systemic BP delivery. In one study, systemic BP delivery negatively influenced implant osseointegration. Rough-surfaced and polished implants were used in 11 and one study respectively. In 3 studies implant surface characteristics remained unclear.

CONCLUSION

Within the limits of the present study, it is concluded that systemic BP delivery enhances implant osseointegration in animals with induced osteoporotic conditions. However, in a clinical scenario, the potential risk of BP related ONJ in osteoporotic patients undergoing dental implant therapy cannot be disregarded.