Osteonecrosis of the jaw related to the use of bisphosphonates

Therapeutic strategy for atypical ulnar fracture in long use of bisphosphonate: A systematic review

BACKGROUND

Atypical fractures are caused by the combined effects of severe suppression of bone metabolism (SSBT) due to long-term bisphosphonate therapy and chronic repetitive bone microdamage. Atypical ulnar fractures (AUFs) due to SSBT are rare, and there is no standard treatment strategy for such fractures. The relevant literature was reviewed, and the treatment strategy for AUF is discussed.

METHODS

A systematic review was conducted. All studies on ulnar fractures in individuals with a history of bisphosphonate use were included, and the data were extracted and analyzed from the perspective of the therapeutic strategy.

RESULTS

Forty limbs of 35 patients were included. As for the treatment of AUF, 31 limbs were treated surgically, and conservative treatment with casting was performed for 9 limbs. The bone fusion rate was 22/40 (55.0%), and non-union was seen in all patients treated conservatively. There was a significant difference in the bone fusion rate between patients with surgical treatment and those with conservative treatment. The bone fusion rate of patients with parathyroid hormone (PTH) and surgery was 82.3% (14/17 limbs); the bone fusion rate with PTH and bone graft was 69.2% (9/13 limbs). However, there were no significant differences in the fusion rate in the groups with or without PTH, with or without bone grafting, or the combination of the two treatments. There was also no significant difference in the bone fusion rate in the groups with or without low-intensity pulsed ultrasound (LIPUS) treatment.

CONCLUSIONS

Based on the literature review, surgery is necessary to achieve bone union, but surgery alone is not adequate to achieve bony union. Bone grafting and the administration of PTH and LIPUS may promote early bone fusion, but the present study did not show significant advantages of these additional treatments for bone union.

Pathophysiology and therapeutic advances in myeloma bone disease

Bone disease is the most common complication in patients with multiple myeloma (MM), and it may lead to skeletal-related events (SREs) such as bone pain, pathological fractures, and spinal cord compression, which impair a patients' quality of life and survival. The pathogenesis of myeloma bone disease (MBD) involves disruption of bone reconstitution balance including excessive activation of osteoclasts, inhibition of osteoblasts, and participation of osteocytes and bone marrow stromal cells. Various factors, such as the receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin (OPG), dickkopf-1 (DKK-1), sclerostin, and activin-A, are involved in the development of MBD. Bisphosphonates and the anti-RANKL antibody denosumab are currently the main treatment options for MBD, delaying the onset of SREs. Denosumab is preferred in patients with MM and renal dysfunction. Although effective drugs have been approved, antimyeloma therapy is the most important method for controlling bone disease.

TNF-inhibitors or bisphosphonates in chronic nonbacterial osteomyelitis? - Results of an international retrospective multicenter study

Chronic nonbacterial osteomyelitis (CNO) can cause significant morbidity, including bone pain and damage. In the absence of clinical trials, treatments include non-steroidal anti-inflammatory drugs, corticosteroids, TNF-inhibitors (TNFi) and/or bisphosphonates. In a retrospective chart review in the United Kingdom and Germany, we investigated response to TNFi and/or pamidronate. Ninety-one patients were included, receiving pamidronate (n = 47), TNFi (n = 22) or both sequentially (n = 22). Patients with fatigue [p = 0.003] and/or arthritis [p = 0.002] were more frequently treated with TNFi than pamidronate. Both therapies were associated with clinical remission at 6 months, and reduction of bone lesions on MRI at 12 months. While not reaching statistical significance, pamidronate resulted in faster resolution of MRI lesions. Fewer flares were observed with TNFi. Failure to respond to pamidronate was associated with female sex [p = 0.027], more lesions on MRI [p = 0.01] and higher CRP levels [p = 0.03]. Randomized clinical trials are needed to confirm observations and generate evidence.

Myeloma Bone Disease: A Comprehensive Review

Multiple myeloma (MM) is a neoplastic clonal proliferation of plasma cells in the bone marrow microenvironment, characterized by overproduction of heavy- and light-chain monoclonal proteins (M-protein). These proteins are mainly found in the serum and/or urine. Reduction in normal gammaglobulins (immunoparesis) leads to an increased risk of infection. The primary site of origin is the bone marrow for nearly all patients affected by MM with disseminated marrow involvement in most cases. MM is known to involve bones and result in myeloma bone disease. Osteolytic lesions are seen in 80% of patients with MM which are complicated frequently by skeletal-related events (SRE) such as hypercalcemia, bone pain, pathological fractures, vertebral collapse, and spinal cord compression. These deteriorate the patient's quality of life and affect the overall survival of the patient. The underlying pathogenesis of myeloma bone disease involves uncoupling of the bone remodeling processes. Interaction of myeloma cells with the bone marrow microenvironment promotes the release of many biochemical markers including osteoclast activating factors and osteoblast inhibitory factors. Elevated levels of osteoclast activating factors such as RANK/RANKL/OPG, MIP-1-α., TNF-α, IL-3, IL-6, and IL-11 increase bone resorption by osteoclast stimulation, differentiation, and maturation, whereas osteoblast inhibitory factors such as the Wnt/DKK1 pathway, secreted frizzle related protein-2, and runt-related transcription factor 2 inhibit osteoblast differentiation and formation leading to decreased bone formation. These biochemical factors also help in development and utilization of appropriate anti-myeloma treatments in myeloma patients. This review article summarizes the pathophysiology and the recent developments of abnormal bone remodeling in MM, while reviewing various approved and potential treatments for myeloma bone disease.

Therapeutic targets in myeloma bone disease

Multiple myeloma (MM) is the second most common haematological malignancy and is characterized by a clonal proliferation of neoplastic plasma cells within the bone marrow. MM is the most frequent cancer involving the skeleton, causing osteolytic lesions, bone pain and pathological fractures that dramatically decrease MM patients' quality of life and survival. MM bone disease (MBD) results from uncoupling of bone remodelling in which excessive bone resorption is not compensated by new bone formation, due to a persistent suppression of osteoblast activity. Current management of MBD includes antiresorptive agents, bisphosphonates and denosumab, that are only partially effective due to their inability to repair the existing lesions. Thus, research into agents that prevent bone destruction and more importantly repair existing lesions by inducing new bone formation is essential. This review discusses the mechanisms regulating the uncoupled bone remodelling in MM and summarizes current advances in the treatment of MBD. LINKED ARTICLES: This article is part of a themed issue on The molecular pharmacology of bone and cancer-related bone diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.9/issuetoc.

Pediatric chronic nonbacterial osteomyelitis of the mandible: Seattle Children's hospital 22-patient experience

BACKGROUND

Studies evaluating treatment responses for chronic nonbacterial osteomyelitis (CNO) are lacking. We aimed to measure and compare response rates of medical treatments, time to response of medical treatments among patients with CNO of the mandible, and describe bacterial contamination rates from biopsy.

METHODS

We conducted a retrospective chart review of all patients diagnosed with CNO of mandible between 2003 and 2017 and extracted demographic, clinical, laboratory, imaging and surgical data. Detailed medication use and response to medications were recorded. The primary outcome was response to medical treatments defined as improvement of presenting symptoms, inflammatory markers, and imaging if available. Medical treatments included nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, disease modifying anti rheumatic drugs (DMARDs), anti-tumor necrosis factor (TNF) therapy, and pamidronate. Descriptive analysis was performed when appropriate. Multivariable logistic regression and Kaplan-Meier curves were applied to compare the responses to medical treatments and time to full response.

RESULTS

We identified 22 patients with a median age of 11 and 36% were female. Four patients (18%) had multifocal bone lesions. CT findings (n = 21) showed lytic lesions (62%) and sclerosis (90%). MRI (n = 14) revealed hyperintensity within bone marrow (100%), soft tissue (71%) and bony expansion (71%). Non-antibiotic treatments including NSAIDs (n = 18), glucocorticoids (n = 10), DMARDs (n = 9), anti-TNF therapy (n = 5) and pamidronate (n = 6) were applied. Rates of full responses to anti-TNF therapy (60%) and pamidronate (67%) were higher than that to NSAIDs (11%) (p < 0.05). Patients receiving pamidronate responded more rapidly than those receiving anti-TNF therapy (median two vs 17 months, p = 0.01) when there was a full response. All had bone biopsies. Intraoral biopsy was performed in 12 of 13 operated in our center and the most common contaminants were Neisseria spp and Streptococcus viridians.

CONCLUSION

Both anti-TNF and pamidronate appeared superior to NSAIDs alone in treating mandibular CNO. Patients receiving pamidronate responded faster than those receiving anti-TNF therapy.

Bones in Multiple Myeloma: Imaging and Therapy

F-fluorodeoxyglucose (FDG)-PET/CT, MRI, and other novel imaging modalities in the management of disease in patients with plasma cell dyscrasias. We also review the state of the art in treatment of MM bone disease (MMBD) and the role of bisphosphonates and denosumab, a monoclonal antibody that binds and blocks the activity of receptor activator of nuclear factor-kappa B ligand (RANKL), which was recently approved by the U.S. Food and Drug Administration for MMBD.

Comparing the Antimicrobial In Vitro Efficacy of Amoxicillin/Metronidazole against Azithromycin-A Systematic Review

On account of its proven clinical efficacy, the combination of systemically administered amoxicillin and metronidazole is frequently adjuncted to non-operative periodontal therapy and well documented. Potential drawbacks of this regimen, e.g., side effects and problems with the compliance, led to an ongoing search for alternatives. Azithromycin, an antibiotic extensively used in general medicine, has recently found its niche in periodontal therapy as well. This systematic review aimed to analyze the in vitro antimicrobial efficacy of amoxicillin plus metronidazole versus azithromycin. For this purpose, a systematic literature search was performed, and studies published up to 29 March 2018 referenced in Medline, Embase, Cochrane, and Biosis were independently screened by two authors. An additional hand search was performed and studies focusing on the evaluation of in vitro antimicrobial efficacy of amoxicillin + metronidazole or azithromycin on bacteria from the subgingival biofilm were included. English and German language research reports were considered. From 71 identified articles, only three articles were eligible for inclusion. These studies showed heterogeneity in terms of analytical methods and strains explored. However, all studies used multispecies biofilm models for analysis of the antimicrobial activity. Unanimously, studies reported on more pronounced antimicrobial effects when applying the combination of amoxicillin + metronidazole, compared to azithromycin. Based on the few studies available, the combination of amoxicillin + metronidazole seemed to display higher antimicrobial efficacy in vitro than azithromycin.

Multiple Myeloma and Bone: The Fatal Interaction

Multiple myeloma (MM) is the second-most-common hematologic malignancy and the most frequent cancer to involve bone. MM bone disease (MMBD) has devastating consequences for patients, including dramatic bone loss, severe bone pain, and pathological fractures that markedly decrease the quality of life and impact survival of MM patients. MMBD results from excessive osteoclastic bone resorption and persistent suppressed osteoblastic bone formation, causing lytic lesions that do not heal, even when patients are in complete and prolonged remission. This review discusses the cellular and molecular mechanisms that regulate the uncoupling of bone remodeling in MM, the effects of MMBD on tumor growth, and potential therapeutic approaches that may prevent severe bone loss and repair damaged bone in MM patients.

Oral alendronate in pediatric chronic recurrent multifocal osteomyelitis

Chronic recurrent multifocal osteomyelitis (CRMO) primarily affects children and adolescents, and is characterized by episodic sterile osteomyelitis over several years. No definitive treatment is available. Non-steroidal anti-inflammatory drugs (NSAID) are common first-line agents, but provide limited improvement in bone pain and do not affect disease duration. Several agents are utilized in the case of non-response to NSAID, including corticosteroids, methotrexate, and tumor necrosis factor-blocking agents. Bisphosphonates are increasingly being used. Most case series involve cyclic i.v. pamidronate, but this restricts the social lives of children and their families. Although oral medication has advantages over cyclic i.v. infusion because it does not require repeated hospital admissions, there have been no reports on treatment with oral bisphosphonates, such as alendronate, in pediatric CRMO patients. This case report describes the use of oral bisphosphonate as an alternative treatment in CRMO patients in whom standard therapy has failed.

Recurrent Monostotic Fibrous Dysplasia in the Mandible

Fibrous dysplasia (FD) is a condition in which normal bone marrow is replaced by an abnormal proliferation of new fibrous connective tissue. Female patient, white, 20 years old, attended the dental clinic reporting a slow increase in volume in the right mandible region over the last 5 years. She was examined by imaging: the panoramic X-ray revealed a lesion with the appearance of ground glass while the cone-beam computed tomography showed an extensive lesion in the region of the right hemimandible. The histopathological examination was compatible with fibrous dysplasia. Bone gammagraphy was indicated, plus an endocrinological study to eliminate polyostotic forms, which produced a negative result. Monostotic fibrous dysplasia in the right hemimandible was diagnosed. Conservative surgery was carried out and after 1 year recurrence of the tumour was observed. We may conclude that conservative surgery might not be the best choice for treatment for monostotic fibrous dysplasia in the mandible and that other options must be considered, such as radical surgery or the use of bisphosphonates. In our study, we may also conclude that it is very important to explain to the patient the possibility of recurrence of the lesion and the need for monitoring with periodic imaging studies.

Bone disease in multiple myeloma: pathophysiology and management

Myeloma bone disease (MBD) is a devastating complication of multiple myeloma (MM). More than 80% of MM patients suffer from destructive bony lesions, leading to pain, fractures, mobility issues, and neurological deficits. MBD is not only a main cause of disability and morbidity in MM patients but also increases the cost of management. Bone destruction and lack of bone formation are main factors in the development of MBD. Some novel factors are found to be involved in the pathogenesis of MBD, eg, receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegerin (OPG) system (RANKL/OPG), Wingless (Wnt), dickkopf-1 (Wnt/DKK1) pathway. The addition of novel agents in the treatment of MM, use of bisphosphonates and other supportive modalities such as radiotherapy, vertebroplasty/kyphoplasty, and surgical interventions, all have significant roles in the treatment of MBD. This review provides an overview on the pathophysiology and management of MBD.

Conservative treatment of bisphosphonate-related osteonecrosis of the jaw in multiple myeloma patients

The use of intravenous bisphosphonates (pamidronate or zoledronic acid) is the cornerstone for the management of multiple myeloma-(MM-) related bone disease. However, osteonecrosis of the jaw (ONJ) is a rare, but sometimes difficult to manage, adverse effect of bisphosphonates therapy. A retrospective review of all MM patients who were treated with bisphosphonates in our department, from 2003 to 2013, and developed ONJ was performed. According to inclusion criteria, 38 patients were studied. All these patients were treated as conservatively as possible according to the American Association of Oral and Maxillofacial Surgeons criteria. Patients were managed with observation, oral antibacterial mouth rinse with chlorhexidine, oral antibiotics, pain control with analgesics, nonsurgical sequestrectomy with or without simultaneous administration of antibiotics, or major surgery with or without antibiotics. Healing of the lesions was achieved in 23 (60%) patients who were treated with conservative measures; the median time to healing was 12 months (95% CI: 4–21). The number of bisphosphonates infusions influenced the time to healing: the median time to healing for patients who received <16 infusions was 7 months and for those with >16 infusions was it 14 months (P = 0.017). We conclude that a primarily nonsurgical approach appears to be a successful management strategy for bisphosphonate-related ONJ.

Incidence and risk of osteonecrosis of the jaw among the Taiwan osteoporosis population

Evidence of the incidence and risk of osteonecrosis of the jaw (ONJ) in Asian osteoporosis populations receiving different osteoporosis medications is lacking. We found that there is no excess incidence of or risk for ONJ in osteoporosis patients >50 years old using alendronate as compared with patients using raloxifene or calcitonin under real-world conditions in Taiwan.

INTRODUCTION

To provide information on ONJ in Asian populations, this study compares the incidence and risk of ONJ between patients receiving alendronate and those receiving non-bisphosphonate osteoporosis medications in Taiwan.

METHODS

Enrollees in the National Health Insurance Research Database (NHIRD) from 2003 to 2007, aged above 50 years, with vertebral/hip fracture, and new to osteoporosis therapy were recruited. Patients with Paget's disease or cancer during the baseline period were excluded. Patients were classified into either the alendronate or the calcitonin/raloxifene (control) group according to their exposure during follow-up. Previously proposed possible ONJ diagnosis codes were adopted as potential ONJ cases, but qualifying cases also had a repeated ONJ diagnosis within 8 weeks of the first diagnosis and received one or more broad-spectrum oral antibiotics. Cox modeling compared the risk of ONJ between the alendronate and the control groups, which were matched using propensity scores. Results were examined in series sensitivity analyses, including different cumulative dose groups.

RESULTS

We found 25 potential ONJ cases in the alendronate (N = 18,030) and 21 in the control groups (N = 25,615). Over the 6-year follow-up period, no increased risk of ONJ in the alendronate group in the original (hazard ratio (HR), 0.87; 95% confidence interval (CI), 0.47-1.58) or propensity score-matched cohorts (HR, 0.86; 95% CI, 0.44-1.69) was found. All comparison groups exhibited a similar incidence of ONJ, ranging from 6.9 to 8.2/10,000 person-years.

CONCLUSION

Under real-world conditions, there is no excess risk for ONJ in osteoporosis patients >50 years old using alendronate as compared with patients using raloxifene or calcitonin.

Expert opinion 2011 on the use of new anti-resorptive agents in the prevention of skeletal-related events in metastatic bone disease

Bisphosphonates have been a mainstay in the treatment of cancer-related bone disease and have greatly reduced the risk of skeletal complications. More recently, clinical studies suggested additional benefits of denosumab over zoledronic acid in the prevention of skeletal related events. Similar adverse event profiles have been reported for bisphosphonates and denosumab, with infrequent occurrences of osteonecrosis of the jaw with both agents, higher incidence of renal deterioration with zoledronic acid, and higher incidence of hypocalcaemia with denosumab. Based on current evidence, the American Society of Clinical Oncology (ASCO) and National Comprehensive Cancer Network (NCCN) guidelines do not recommend one drug class over the other in patients with metastatic bone disease. Denosumab, however, may present advantages over bisphosphonates in patients suffering from chronic renal insufficiency. Further research and growing clinical experience will refine the evidence based on which decisions in daily clinical practice can be taken.

Myeloma bone disease: Pathophysiology and management

Multiple myeloma bone disease is marked by severe dysfunction of both bone formation and resorption and serves as a model for understanding the regulation of osteoblasts (OBL) and osteoclasts (OCL) in cancer. Myeloma bone lesions are purely osteolytic and are associated with severe and debilitating bone pain, pathologic fractures, hypercalcemia, and spinal cord compression, as well as increased mortality. Interactions within the bone marrow microenvironment in myeloma are responsible for the abnormal bone remodeling in myeloma bone disease. Myeloma cells drive bone destruction that increases tumor growth, directly stimulates the OCL formation, and induces cells in the marrow microenvironment to produce factors that drive OCL formation and suppress OBL formation. Factors produced by marrow stromal cells and OCL promote tumor growth through direct action on myeloma cells and by increasing angiogenesis. Current therapies targeting MMBD focus on preventing osteoclastic bone destruction; however regulators of OBL inhibition in MMBD have also been identified, and targeted agents with a potential anabolic effect in MMBD are under investigation. This review will discuss the mechanisms responsible for MMBD and therapeutic approaches currently in use and in development for the management of MMBD.

Factors predicting the prognosis of oral alendronate-related osteonecrosis of the jaws: a 4-year cohort study

BACKGROUND

Studies concerning prognostic factors specific for alendronate-related osteonecrosis of the jaws (ONJ) are rare.

METHODS

We surveyed a cohort of 100 osteoporotic patients with 111 alendronate-related ONJ lesions treated during a 4-year period. Prognostic values of clinical variables and serum markers of bone turnover were assessed by univariate and multivariate analyses.

RESULTS

The cumulative complete response rate at 6 months was 48.65%. Serum bone-specific alkaline phosphatase (BSAP) level >10 μg/L, lesion depth ≦ 10 mm, and lesions in anterior regions denoted a better chance of healing within 6 months and the adjusted hazard ratios were 2.48 (95% confidence interval [CI], 1.41-4.37), 2.71 (95% CI, 1.57-4.70), and 3.94 (95% CI, 1.87-8.30), respectively.

CONCLUSIONS

Early discovery of lesions and prevention of their deeper extension are crucial for improving the prognosis of alendronate-related ONJ. A higher pretreatment level of BSAP indicates a better prognosis.

The effect of the combination of bisphosphonates and conventional chemotherapy on bone metabolic markers in multiple myeloma patients

PURPOSE

Urinary N-terminal telopeptides of type I collagen (uNTX), serum bone alkaline phosphatase (sBAP) have been acknowledged in observing bone metastases of solid tumors. The paper is designed to study the value of clinical application of uNTX and sBAP in the treatment of multiple myeloma (MM), as well as the action of bisphosphonates for osteolytic bone lesion.

METHODOLOGY

Thirty-three MM cases were treated with bisphosphonates (hereinafter called clodronate therapy group) and 20 MM cases were treated with simple chemotherapy (hereinafter called control group). uNTX and sBAP were tested during the courses of treatment three times (pretreatment, 3 months, and 6 months). uNTX was tested by enzyme-linked immunosorbent assay. sBAP was tested by chemiluminescence analysis. All the results were analyzed with t-test by using SPSS 11.0.

RESULTS

There were no significant differences between therapy and control groups: in uNTX (173.74 ± 14.55) and (129.79 ± 12.13) μg/l before treatment (P > 0.05). After 6 months there were significant differences between them: (85.71 ± 8.23) and (121.59 ± 12.43) μg/l (P < 0.05). And also there were significant differences among the courses in the therapy group. There were no significant differences between therapy and control groups in sBAP concentration: (4.78 ± 0.55) and (8.42 ± 1.32) μg/l before treatment (P > 0.05). After 6 months there were significant differences between them: (16.01 ± 0.52) and (9.62 ± 1.29) μg/l (P < 0.001). And also there were significant differences among the courses in the therapy group.

CONCLUSION

uNTX and sBAP were important to measure the situation of the osteolytic bone lesion in MM. Bisphosphonates can significantly reduce bone degradation and metabolism, improve the synthesis, which is valuable for the treatment of MM cases.

Antibiotic effects on bacterial profile in osteonecrosis of the jaw

OBJECTIVE

Oral infection is considered to play a critical role in the pathogenesis of bisphosphonate-related osteonecrosis of the jaw (BRONJ), and antibiotic therapy has become a mainstay of BRONJ therapy. This study was aimed to investigate the effect of antibiotics on bacterial diversity in BRONJ tissues.

MATERIALS AND METHODS

The bacterial profile from soft tissues associated with the BRONJ lesion was determined using 16S rRNA-based denaturing gradient gel electrophoresis (DGGE) and sequencing. Twenty BRONJ subjects classified as stage 0-2 were enrolled in this study, and patient groups were divided into an antibiotic cohort (n=10) treated with systemic antibiotic and a non-antibiotic cohort (n=10) with no prior antibiotic therapy.

RESULTS

The DGGE fingerprints indicated no significant differences in bacterial diversity of BRONJ tissue samples. Patients on antibiotics had higher relative abundance of phylum Firmicutes with bacterial species, Streptococcus intermedius, Lactobacillus gasseri, Mogibacterium timidum, and Solobacterium moorei, whereas patients without antibiotics had greater amounts of Parvimonas micra and Streptococcus anginosus. Thirty percent of bacterial populations were uncultured (yet-to be cultured) phylotypes.

CONCLUSION

This study using limited sample size indicated that oral antibiotic therapy may have a limited efficacy on the bacterial population associated with BRONJ lesions.

Effects of antiresorptive agents on osteomyelitis: novel insights into the pathogenesis of osteonecrosis of the jaw

The effects of antiresorptive agents (e.g., alendronate [Aln], osteoprotegerin [OPG]) on bone infection are unknown. Thus, their effects on implant-associated osteomyelitis (OM) were investigated in mice using PBS (placebo), gentamycin, and etanercept (TNFR:Fc) controls. None of the drugs affected humoral immunity, angiogenesis, or chronic infection. However, the significant (P < 0.05 vs. PBS) inhibition of cortical osteolysis and decreased draining lymph node size in Aln- and OPG-treated mice was associated with a significant (P < 0.05) increase in the incidence of high-grade infections during the establishment of OM. In contrast, the high-grade infections in TNFR:Fc-treated mice were associated with immunosuppression, as evidenced by the absence of granulomas and presence of Gram(+) biofilm in the bone marrow. Collectively, these findings indicate that although antiresorptive agents do not exacerbate chronic OM, they can increase the bacterial load during early infection by decreasing lymphatic drainage and preventing the removal of necrotic bone that harbors the bacteria.

Oral bisphosphonate-related osteonecrosis of the jaw: the first report in Asia

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a serious side effect of bisphosphonate therapy. The incidence of BRONJ is known to be low among patients treated with oral bisphosphonates. We investigated the prevalence, demographics, clinical manifestations, and treatment outcome of 24 patients with oral BRONJ in Asian populations.

INTRODUCTION

The long-term safety of oral bisphosphonates is clinically important considering the rare but potentially serious complications such as bisphosphonate-related osteonecrosis of the jaw (BRONJ) versus the effect of reducing and preventing osteoporotic fracture. The incidence of BRONJ is known to be low among patients treated with oral bisphosphonates around the world. However, the prevalence in those taking oral bisphosphonates for osteoporosis in Asian populations is unknown. Moreover, a recent article, showing that the majority of reported patients who received alendronate were Asian American, raised concern about the prevalence of oral BRONJ in Asian populations. The objective of this study was to investigate the estimated prevalence, clinical characteristics, and treatment outcome of oral BRONJ in Asian populations.

METHODS

From October 2005 to December 2008, a retrospective review of medical charts identified 24 patients receiving oral bisphosphonates diagnosed as BRONJ at the Department of Oral and Maxillofacial Surgery, Yonsei University Dental Hospital, Seoul, South Korea.

RESULTS

The estimated prevalence of oral BRONJ was 0.05-0.07%. The average oral bisphosphonate treatment duration was 43.1 months (range, 5-120 months). Treatment with oral antibiotics and/or surgery including sequestrectomy or alveolectomy showed relatively favorable results.

CONCLUSIONS

The prevalence of oral BRONJ in Korea is similar to that reported previously in Western populations. We suggest that recognition of BRONJ and appropriate management pre- and post-dental surgery might reduce the frequency of BRONJ among patients receiving oral bisphosphonates.

Osteonecrosis of the jaws: clinicopathologic and radiologic characteristics, preventive and therapeutic strategies

BACKGROUND

Bisphosphonate (BP) use has increased dramatically in recent years, becoming an integral part of the overall antineoplastic management of patients with metastatic bone disease. Even though their application has shown to be effective in reducing pain and minimizing the risk of skeletal-related events, their administration may bring also adverse events such osteonecrosis of the jaws (ONJ).

METHODS

After a thorough review of the literature, important aspects of the pathophysiology, diagnosis, prevention, and treatment of ONJ are presented.

RESULTS

ONJ is evident in up to 10% of patients receiving intravenous BP treatment. Despite the fact that its exact pathophysiology is unknown, it is characterized by bone necrosis that can occur either spontaneously or after dental surgery or tooth extraction. Panoramic radiographs are useful for the diagnosis and routine assessment of patients and computed tomography can differentiate between ONJ and metastatic disease. Additionally, magnetic resonance imaging depicts local disease extension readily, and scintigraphy is the most sensitive imaging modality for detecting early involvement. Preventive measures and routine dental evaluations are essential components of the overall patient management. In the event of ONJ, stage I or II should be managed conservatively, whereas more advanced stages (III and IV) should be treated surgically.

CONCLUSION

ONJ is a well-defined clinical entity that all medical and dental doctors should be aware of, since if it is not dealt with readily and effectively, it may deteriorate the clinical status and quality of life of affected patients.

A novel animal model to study non-spontaneous bisphosphonates osteonecrosis of jaw

The aim of this study was to evaluate a novel animal model of bisphosphonates-associated osteonecrosis, which realistically recapitulates the same pathological human condition. Five Wistar rats were given intravenous zoledronic acid 0.04 mg once a week for 5 weeks. After 2 weeks, the animals underwent the extraction of an upper molar, producing a 4 mm-diameter bone defect on the same site. After 7 weeks from the extraction, the animals were clinically examined and a bone scintigraphy was carried out. After an additional week, the rats were killed and both Computerized Tomography and histological analysis were performed. Five rats, not treated with zoledronic acid and exposed to the same surgical treatment, were used as controls. At 7 weeks after the extraction, all the rats treated with zoledronic acid showed expansion of the defect and bone exposure. These features were confirmed by bone scintigraphy. The rats of the control group demonstrated epithelialization of the bone defect and a normal uptake of the contrast medium during the scan. The Computerized Tomography scan disclosed irregularity of the cortical margin and bone destruction, which were not evident in the control group. On microscopy, the samples showed necrotic bone, loss of osteocytes and peripheral resorption without inflammatory infiltrate, while the controls showed normal bone healing. The rat treated with zoledronic acid can be considered a novel, reliable and reproducible animal model to understand better the pathophysiology of osteonecrosis of the jaw and to develop a therapeutic approach.

Osteotomy and primary wound closure in bisphosphonate-associated osteonecrosis of the jaw: a prospective clinical study with 12 months follow-up

GOALS OF WORK

This is a prospective clinical study aimed at assessing the success rate of osteotomy and primary wound closure in patients with bisphosphonate-associated osteonecrosis of the jaw (BONJ).

MATERIALS AND METHODS

Fifty patients who had received bisphosphonates intravenously and subsequently suffered from BONJ were included in the study. All patients underwent osteotomy of the affected jaw bone region and primary wound closure under general anaesthesia. They were followed up bimonthly for a period of 12 months.

RESULTS

Macroscopically altered bone could be completely removed in all cases. In two patients with plasmocytoma, major bleeding occurred postoperatively that required monitoring in an intensive care unit. In two cases, recurrence of BONJ was diagnosed during the first 2 months. In three patients, recurrence appeared between the fourth and the sixth month. In these cases, an additional osteotomy had to be performed. Six patients died during the follow-up period. In the remaining 39 patients, no signs of recurrence could be detected during the follow-up of 12 months. The success rate of the surviving patients was 89% after 1 year.

CONCLUSION

Due to the high success rate of osteotomy and primary wound closure, it should be checked for every patient suffering from BONJ if osteotomy is a viable treatment option.

Dental management of patients at risk of osteochemonecrosis of the jaws: a critical review

Osteonecrosis of the jaw bones is a complication of bisphosphonate (BP) drug usage characterised by trans-mucosal exposure of necrotic bone, often followed by infection and pain. Osteonecrosis is observed in cancer patients on high-potency intravenous BP more frequently than in osteoporotic individuals using low-potency oral BP. The management of osteonecrosis caused by BP is often unsatisfactory and control of risk factors is considered the most effective means of prevention. Surgical manipulation and dental infection of the jawbone are the major risk factors, hence it is suggested that careful management of oral health and relevant dental procedures may decrease the risk of osteonecrosis in individuals on BP. Recommendations for dentists and oral surgeons have been suggested by different groups of clinicians but they are often controversial and there is no clear evidence for their efficacy in reducing the likelihood of osteonecrosis development. This report critically reviews current dental recommendations for individuals using BP with the aim of helping the reader to transfer them into practice as part of pragmatic and non-detrimental clinical decisions making.

Cathepsin K inhibitors for osteoporosis and potential off-target effects

Cathepsin K is a highly potent collagenase and the predominant papain-like cysteine protease expressed in osteoclasts. Cathepsin K deficiencies in humans and mice have underlined the central role of this protease in bone resorption and, thus, have rendered the enzyme as an attractive target for anti-resorptive osteoporosis therapy. In the past decade, a lot of efforts have been made in developing highly potent, selective and orally applicable cathepsin K inhibitors. Some of these inhibitors have passed preclinical studies and are presently in clinical trials at different stages of advancement. The development of the inhibitors and preliminary results of the clinical trials revealed problems and lessons concerning the in situ specificity of the compounds and their tissue targeting. In this review, we briefly summarize the history of cathepsin K research and discuss the current development of cathepsin K inhibitors as novel anti-resorptives for the treatment of osteoporosis. We also discuss potential off-target effects of cathepsin K inhibition and alternative applications of cathepsin K inhibitors in arthritis, atherosclerosis, blood pressure regulation, obesity and cancer.

Pattern of intravenous bisphosphonate use in outpatient care in Germany

PURPOSE

Intravenous bisphosphonate therapy has recently been associated with the development of an osteonecrosis of the jaws (ONJ). If new adverse events have been linked to drugs, basic information on drug exposure in routine care is essential. The aim of this study was to investigate prevalence as well as duration and cumulative doses of intravenous bisphosphonate treatment.

METHODS

We analysed data of the statutory health insurance company Gmünder ErsatzKasse (GEK) over the years 2000-2006. We first estimated treatment prevalence in 2006. We further studied a cohort of new users of intravenous bisphosphonates who initiated treatment between 1 January 2001 and 31 December 2005. We used the Kaplan-Meier method to estimate the time to end of treatment (composite of discontinuation and death).

RESULTS

A total of 1024 patients received at least one dose of intravenous bisphosphonates in 2006. The most commonly prescribed agent was zoledronate (53.7%). After standardizing for sex and age, an estimated 0.1% of the German population would have been treated in 2006. Of 1259 new users in 2001-2005, an estimated 40% of men and 22% of women died within 12 months. The median treatment duration was 3.5 months in men and 5.7 months in women. This difference disappears when studying only survivors.

CONCLUSIONS

Although our study suggests that intravenous bisphosphonates were prescribed mainly for short durations, this result is strongly influenced by the fact that new users had a poor prognosis with a short life expectancy.

Bisphosphonate-related osteonecrosis of the jaw is associated with polymorphisms of the cytochrome P450 CYP2C8 in multiple myeloma: a genome-wide single nucleotide polymorphism analysis

We have explored the potential role of genetics in the development of osteonecrosis of the jaw (ONJ) in multiple myeloma (MM) patients under bisphosphonate therapy. A genome-wide association study was performed using 500 568 single nucleotide polymorphisms (SNPs) in 2 series of homogeneously treated MM patients, one with ONJ (22 MM cases) and another without ONJ (65 matched MM controls). Four SNPs (rs1934951, rs1934980, rs1341162, and rs17110453) mapped within the cytochrome P450-2C gene (CYP2C8) showed a different distribution between cases and controls with statistically significant differences (P = 1.07 × 10−6, P = 4.231 × 10−6, P = 6.22 × 10−6, and P = 2.15 × 10−6, respectively). SNP rs1934951 was significantly associated with a higher risk of ONJ development even after Bonferroni correction (P corrected value = .02). Genotyping results displayed an overrepresentation of the T allele in cases compared with controls (48% vs 12%). Thus, individuals homozygous for the T allele had an increased likelihood of developing ONJ (odds ratio 12.75, 95% confidence interval 3.7-43.5).