Skeletal complications of bisphosphonate use: what the radiologist should know

Visualising cervical lymph nodes in jaw osteonecrosis using diffusion-weighted imaging

OBJECTIVES

This study aimed to apply diffusion-weighted imaging to the evaluation of cervical lymph nodes affected by medication-related osteonecrosis of the jaw (MRONJ).

METHODS

This retrospective study analysed the diffusion-weighted imaging data of 70 patients with or without MRONJ (Stages 0-3). The mean apparent diffusion coefficient (ADC) values of the submandibular (level IB) and superior internal jugular (level IIA) nodes in the control and MRONJ groups were calculated, and differences were analysed using the Mann-Whitney test. Moreover, receiver operating characteristic (ROC) curve analysis was performed to evaluate the ability of ADC values to predict lymph nodes that were affected by MRONJ. p < 0.05 was considered statistically significant.

RESULTS

The median [interquartile range] (×10-3 mm2/s) of level IB was 0.74 [0.7-0.81] and 0.93 [0.84-1.09] and that of level IIA was 0.79 [0.76-0.85] and 0.97 [0.84-1.06] in the control and MRONJ groups respectively. ROC analysis revealed that the ADC value had excellent ability to discriminate between the control and MRONJ groups.

CONCLUSIONS

The study findings indicate that diffusion-weighted imaging can contribute to differentiation of MRONJ from other cervical lymph node diseases and facilitate early detection of MRONJ.

Rat Calvaria Model Mimicking the Intraoral Lesion of Medication-Related Osteonecrosis in the Jaw: A Preliminary Test

Numerous preclinical intraoral models have been proposed to study medication-related osteonecrosis of the jaws (MRONJ). However, an extraoral animal model is necessary to investigate the effects of interventions such as grafts or direct therapeutics. This study aimed to establish a MRONJ rat model on the calvaria. Seven rats were allocated to either the control or MRONJ group. The MRONJ group received injections of zoledronic acid and dexamethasone to induce osteonecrosis over 4 weeks. Two weeks after these injections, the maxillary first molar was extracted, and two calvaria defects were created using a 4 mm trephine burr. One defect was left untreated, while the other was filled with harvested calvaria bone. A histological examination of all calvaria in the MRONJ group revealed avascular necrosis and the destruction of cortical bone. An independent t-test and Pearson's correlation coefficient were used for statistical analysis and the evaluation of alveolar and calvaria defects. The total alveolar and calvaria defect volume in the control group was significantly smaller than that in the MRONJ group. A statistically significant correlation was observed between alveolar and calvaria defects (Pearson correlation = 0.6, p = 0.023). The autogenous grafts showed poor results in the MRONJ group since they failed to revascularize and exhibited necrosis. The calvaria in this study successfully mimicked MRONJ lesions with avascular necrosis. This preclinical model could be used to develop treatments that are applicable to MRONJ.

Radiologic findings of osteonecrosis, osteoradionecrosis, osteomyelitis and jaw metastatic disease with cone beam CT

PURPOSE

The purpose of this study was to assess CBCT scans of patients with medication related osteonecrosis of the jaws (MRONJ), osteoradionecrosis (ORN), osteomyelitis (OM) and jaw metastatic disease (JM), evaluate the presence and extent of radiologic findings, identify radiologic parameters that may distinguish the four entities and last, introduce a new modified radiographic index (CRIm), in order to contribute to the diagnosis of these conditions.

METHODS

Τwo major databases were retrospectively searched for fully documented and diagnosed CBCT scans of MRONJ, ORN, OM and JM from 2006 to 2019. 335 CBCT scans met the inclusion criteria and were assessed under standardized viewing conditions blindly by 2 observers. The CRIm index proposed in this study evaluates: lytic changes, sclerosis, periosteal bone formation, sequestration, non-healing extraction sockets and other findings which included: sinus implication, inferior alveolar canal implication and jaw fracture. Lytic changes, sclerosis, periosteal bone formation, sequestration and non-healing extraction sockets were scored as: absent (0), localized/single (1) and extensive/multiple (2). Each one of other findings were scored individually as: absent (0) and present (1). For statistical analysis t-test, Pearson's r correlation coefficient, one-way ANOVA and Bonferonni were performed.

RESULTS

Extensive lytic changes were the most common finding, especially for ORN, where it occurred in all CBCT scans (100%). The mean value of the CRIm index differs significantly between CBCT scans with MRONJ and JM, as well as between those with OM and JM (Bonferroni p < 0.001).

CONCLUSIONS

The new modified Composite Radiographic Index introduced in this study, appears to have improved an objective approach to the previously used Composite Radiographic Index by means of cumulative radiologic features. Τhe predominance of certain radiologic features in one or more of these entities may lead the diagnostician towards the correct diagnosis.

Therapy-induced bone changes in oncology imaging with 18F-sodium fluoride (NaF) PET-CT

¹⁸F-Sodium fluoride (¹⁸F-NaF) is a PET tracer that is mostly used in the evaluation of bone metastasis in oncology cases. Recently, ¹⁸F-NaF PET/CT is gaining wide popularity owing to its higher sensitivity over the other conventional bone tracer with higher and rapid single-pass extraction, negligible plasma protein binding, rapid blood, and renal clearance. In the era of constant evolution of cancer therapy regimens, considerable bone health impact is seen in the form of avascular necrosis, insufficiency fractures, among others. A significant number of these therapy-induced changes show high bone turnover and thereby ¹⁸F-NaF accumulation, mimicking metastatic lesions. This article summarizes and illustrates the pattern and morphological features of ¹⁸F-NaF PET/CT findings in these changes in the context of clinical and therapeutic history.

The value of diffusion-weighted imaging in the diagnosis of medication-related osteonecrosis of the jaws

OBJECTIVE

The purpose of this study was to assess apparent diffusion coefficient (ADC) values associated with medication-related osteonecrosis of the jaws (MRONJ) at each stage of the disease compared to controls.

STUDY DESIGN

The magnetic resonance imaging data of 38 patients in the 4 stages of MRONJ and 10 controls were analyzed. Mean ADC values of bone marrow in the controls and patients in each stage of MRONJ were calculated. The significance of differences was analyzed by using the Kruskal-Wallis test and post-hoc Mann-Whitney tests with Bonferroni adjustment. A receiver operating characteristic (ROC) curve was plotted to distinguish controls from MRONJ stage 0. P < .05 was considered statistically significant.

RESULTS

The mean ADC values of controls and stages 0 to 3 were significantly different, with the lowest value in the controls (P < .001). ROC analysis revealed a cutoff ADC value of 1.06 × 10^-3 mm²/s to distinguish between the control group and MRONJ stage 0 patients, producing values of sensitivity, specificity, accuracy, and area under the ROC curve ranging from 0.89 to 0.94.

CONCLUSIONS

The ADC values of bone marrow affected by MRONJ are significantly different among controls and stages 0 to 3. ADC values may be useful for distinguishing normal from MRONJ stage 0.

Bilateral Atypical Femur Fractures Complicated by Carbon Fiber Cephalomedullary Nail Fracture: A Case Report

CASE

A 69-year-old woman with a history of breast cancer, on long-term antiresorptive medications, was treated with carbon fiber cephalomedullary nails for bilateral atypical femur fractures. Her thigh pain was presumed to be from metastatic lesions and was treated with radiation without standard imaging. The index procedure was complicated by a left nail fracture. The patient underwent exchange cephalomedullary nail fixation with plate augmentation. At 1 year, the patient was asymptomatic with radiographs demonstrating healing.

CONCLUSION

This case highlights the importance of appropriate imaging in all patients with thigh pain on antiresorptive therapy and features an uncommon complication of carbon fiber cephalomedullary nail fixation.

Atypical femoral fractures from bisphosphonate in cancer patients - Review

Bisphosphonates are commonly used in patients with metastatic bone disease to prevent skeletal related events. Atypical femur fracture is a known complication of long-term bisphosphonate use but the incidence in cancer patients and pathogenesis are not well known. Several mechanisms of pathogenesis have been proposed including altered angiogenesis, altered bone mechanical properties, micro damage and bone remodeling suppression. Atypical femur fractures are atraumatic or minimally traumatic fractures in the sub trochanteric region or the femoral shaft. Awareness of atypical femur fractures is critical to diagnose and treat them in a timely manner. There is a paucity of data regarding the management of atypical femur fracture in patients with malignancy. Management options of atypical femur fractures include stopping bisphosphonates, initiating calcium/vitamin D supplementation and either surgery with internal fixation or conservative management. In the future, it will be important to explore the effect of continuous vs. intermittent exposure, cumulative dose and length of exposure on the incidence of this complication. Herein, we review the epidemiology, risk factors, management options and proposed mechanisms of pathogenesis of atypical femur fractures.

Molecular imaging of bone metastases using bone targeted tracers

Molecular imaging using bone targeted tracers has been used in clinical practice for almost fifty years and still plays an essential role in the diagnosis and follow-up of bone metastases. It includes both [99mTc]bisphosphonates for bone scan and [18F]NaF for positron emission tomography/computed tomography (PET/CT) which are very sensitive to detect osteoblastic activity, but it is important to consider several aspects to increase the specificity of reported findings (such as specific tracer characteristics and mechanism of action, patient's clinical history, common metastatic patterns, changes after treatment, limitations of the technique, variations and pitfalls). This will enable useful information for clinical management being provided in the report. Furthermore, iatrogenic skeletal adverse events are common and they should also be identified, as they have impact on patient's quality of life. This review makes a brief summary of the mechanism of action of bone targeted tracers, followed by a discussion of classic patterns of bone metastasis, treatment response assessment and iatrogenic skeletal complications. The value of hybrid imaging techniques with bone targeted tracers, including single photon emission computed tomography and PET/CT is also explored. The final part summarizes new bone targeted tracers with superior imaging characteristics that are being developed, and which may further enhance the applications of radionuclide bone imaging.

Medication related osteonecrosis of the jaw in osteoporotic vs oncologic patients-quantifying radiographic appearance and relationship to clinical findings

OBJECTIVES

To explore whether differences exist in the clinical and radiographic presentation of oncologic vs osteoporotic patients with medication-related osteonecrosis of the jaw (MRONJ).

METHODS

We retrospectively assessed panoramic radiographs and CBCT examinations of 70 MRONJ patients receiving antiresorptive medications for the management of either osteoporosis or bone malignancy. Radiographic features of MRONJ were documented and categorized according to severity. A composite radiographic index (CRI) was constructed to account for the heterogeneity in radiographic manifestations of MRONJ and further stratify extent of osseous changes.

RESULTS

Patients with osteoporosis were mostly older females and presented more frequently with Stage 2 MRONJ, while patients with malignancy were equally distributed between males and females, and presented mostly with Stage 1 MRONJ. Most MRONJ lesions in oncologic patients occurred in the mandible, whereas the maxilla and mandible were equally affected in osteoporotic patients. Patients with minimal radiographic changes (low CRI score) often presented with MRONJ in dentate areas, while most patients in medium and high CRI groups presented with MRONJ after recent tooth extraction. The low CRI group consisted of primarily oncologic patients, while osteoporotic vs oncologic patients were divided more evenly in the other CRI groups (p = 0.083). While CRI scores increased with clinical staging, a Spearman's rank correlation coefficient of 0.49 suggests that clinical appearance does not reliably predict osseous changes.

CONCLUSIONS

Our data identify differences in the MRONJ appearance of patients with osteoporosis vs malignancy and emphasize the significance of detailed radiographic assessment, in addition to the clinical appearance, in characterizing the osseous changes of the disease.

Detecting the earliest radiological signs of bisphosphonate-related osteonecrosis

Introduction Oral bisphosphonates are the most commonly prescribed anti-resorptive drugs used in the treatment of osteoporosis, but osteonecrosis of the jaw is a serious complication. The early diagnosis of this destructive side effect is crucial in preventing excessive bone loss, pain and infection.Objective To aid dental practitioners in the early identification of bisphosphonate-related osteonecrosis of the jaw.Method A scoping review was carried out.Data sources We searched MEDLINE via OVID, EMBASE via OVID, Dentistry and Oral Sciences Source (DOSS), Proquest Dissertation and Theses Search, to identify references that described clinical and radiological findings in medication-related osteonecrosis of the jaw (MRONJ).Data selection Nineteen references mentioned the earliest radiological changes in MRONJ with a description of the observations and were included in the analysis.Data synthesis The radiographic signs included osteosclerosis/lysis, widening of the periodontal ligament and thickening of the lamina dura and cortex. To assess the quality of original data on which recommendations had been made, these 19 studies were subjected to a quality appraisal.Conclusion Using bone exposure as a criterion for diagnosis of MRONJ, leads to delayed diagnosis and a poor response to treatment. In those patients at risk of bone exposure with MRONJ, insufficient information is present in the literature to allow the general dental practitioner to reliably identify the radiographic features indicating imminent bone exposure. A well-designed prospective study is needed.

Audit of Atypical Femoral Fractures and a Description of Some of Their Features

PURPOSE

Atypical femoral fractures (AFF) are recently described events related to osteoporosis and, potentially, a rare result of antiresorptive treatment.

METHODS

We set out to audit the diagnosis of AFF in an acute hospital. Charts and radiographs were reviewed retrospectively from patients diagnosed with subtrochanteric femoral fractures according to hospital discharge coding at Vancouver General Hospital (VGH), Canada, from January 2005 to March 2013.

RESULTS

A total of 3084 patients were discharged from the hospital with a diagnosis of hip fracture between 2005 and 2013. Of these, 204 were coded as having had subtrochanteric fractures; 178 of the patients thus coded had radiographic evidence of other fracture types-usually intertrochanteric fractures. Eleven patients did not have available radiographs. Of the remaining 193 patients whose radiographs were reviewed, 24 (12.4%) fulfilled the published criteria for AFF.

OUR OBSERVATIONS WERE

1) laterality: 13 of 24 AFF (54.2%) were right-sided; 2) there was only one incomplete AFF in this series: a completed fracture was an inclusion criterion, but 1 patient with an AFF had both that fracture and an incomplete fracture and further foci of periosteal or endosteal foci of new bone (PENB) involving the contralateral femur; 3) radiologists had only diagnosed AFF in only 1 of the 24 patients with characteristic radiographic signs of AFF; 4) all but 1 patient had a focus of periosteal and/or endosteal new bone (PENB) through which the fracture line invariably passed, and in the 1 exception the radiography was too poor to be sure of this but there was a symmetrical contralateral focus of PENB; 5) in 19 of 24 patients there was an adequate image of part of the contralateral femur and of these 12 (63%) had a contralateral focus of PENB situated ±2.5 cm from the index lesion site when measured from the upper aspect of the greater trochanter, and in another patient a prior fracture of the contralateral femur had been treated surgically and it was at a symmetrical contralateral location from the index fracture.; 6) in 3 of the 19 patients multiple foci of PENB were detected on the lateral aspect of the contralateral femur even though the examination was of limited extent; and 7) AFFs were associated with bisphosphonate medication in 75% of the patients studied.

CONCLUSIONS

Hospital discharge coding misclassified a great majority of femoral fractures as subtrochanteric. As an essential criteria for diagnosing AFF is their subtrochanteric location, this misclassification impaired our ability to retrospectively search for AFF patients. Radiologists tended not to report AFF when typical radiographic characteristics were present. Bilateral and multifocal disease is of interest in pointing to the diagnosis and in suggesting that the mechanism of injury in respect of these unusual fractures is more complex than simple low-energy trauma.

A case of early detection of bisphosphonate-related osteonecrosis of the jaw

Osteonecrosis of the jaws is an adverse reaction associated with the use of bisphosphonates. Although the diagnosis of bisphosphonate-related osteonecrosis of the jaw (BRONJ) is based on symptomatology, it is often detected late because the patients become symptomatic only after osteonecrosis is well established. We describe a case of early oral BRONJ detected by magnetic resonance imaging (MRI) accidentally. Head MRI revealed low signal of T1-weight images in left mandibula. Patient had been treated with minodronate for osteoporosis during 18 months. Based on the MRI findings and medication history, early stage BRONJ could be considered. Therefore minodronate was switched to teriparatide. Thereafter mandible pares-thesias, odontalgia and exposed bone were not observed. This case suggests that MRI is useful for the early detection of BRONJ.

Bisphosphonate-related osteonecrosis of the jaw: an Italian post-marketing surveillance analysis

OBJECTIVE

Although bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) is well recognized, little is known about it in terms of pathophysiology, epidemiology or management. We analyzed all suspected BRONJ reports sent to the Italian Pharmacovigilance Adverse Event Spontaneous Reporting System (Rete Nazionale Farmacovigilanza [RNF]) to determine their pattern and add new information about this relevant issue.

RESEARCH DESIGN AND METHODS

All suspected BRONJ sent to the RNF between 2003 and 2011 were retrieved. After a case-by-case assessment procedure, we analyzed BP type, BP exposure time and time since last use.

RESULTS

Between 2003 and 2011, 555 reports of osteonecrosis of the jaw (ONJ) after BP administration were recorded in the RNF. These events occurred mostly in patients affected by cancer (77.84%) in which zoledronate was the most frequently suspected BP. Most patients experienced ONJ after long-term use of the drug (median time of BP exposure being between 1.3 and 8.8 years). Interestingly, 139 (25.05%) cases of ONJ occurred between 2 and 121 months after BP withdrawal.

CONCLUSION

This study shows that BRONJ can occur much earlier than hitherto reported, adds new data on BRONJ onset following ibandronate treatment and reveals that patients who cease BP-based therapy develop ONJ, raising the question of post-treatment monitoring strategies.

Subtrochanteric femur fractures: review of the complete pathologic spectrum with emphasis on distinguishing imaging features

Subtrochanteric femur fractures result from a variety of mechanisms of injury and underlying pathologies. Radiologists can play a pivotal role by differentiating the etiology of a subtrochanteric femur fracture, which assists the orthopedic surgeon in choosing the correct method of treatment. To provide this valuable service, one must be familiar with the characteristic radiologic features of the numerous causative etiologies, ranging from Paget disease to underlying bone lesions to iatrogenic fractures.

Atypical femur fractures: a review

Bisphosphonates are one of the most commonly prescribed medications for the treatment of osteoporosis. Their use has greatly decreased the number of osteoporosis-related vertebral and nonvertebral fractures. Recently, however, a relationship between long-term bisphosphonate use and subtrochanteric and femoral shaft fractures has been elucidated. These low-energy fractures, termed atypical femur fractures, exhibit unique characteristics in their pathophysiology, presentation, and radiographic appearance compared with more traditional high-energy femur fractures. Here we provide a review based on the most recent literature of the pathophysiology, presentation, evaluation, and management of these fractures. Despite an abundance of literature, atypical femur fractures remain difficult to treat, and surgeons must be aware of the tricks and complications associated with their management.

Imaging findings of bisphosphonate-related osteonecrosis of the jaws: a critical review of the quantitative studies

Objectives. This paper offers a critical review of published information on the imaging strategies used for diagnosing bisphosphonate-associated osteonecrosis of the jaw (BRONJ) in patients taking intravenous bisphosphonates, pointing at the different methodologies and results of existing literature. Methods. Electronic literature search was performed in order to identify as many quantitative studies that discussed the imaging findings of BRONJ up to February 2014. Initially, the search for articles was based on the following four types of imaging modalities for evaluating BRONJ: computed tomography, plain film radiographs, magnetic resonance imaging, and nuclear bone scanning. Results. Eleven out of the 79 initially selected articles met the inclusion criteria. Most of the selected articles were cross-sectional studies. Regarding the selected studies, 54.5% have used plain films radiographs and 54.5% were based on computed tomography findings. All of the selected studies showed a small number of patients and none of the selected studies have tested the accuracy of the imaging examination for evaluating BRONJ. Conclusions. This critical review showed a scarcity of quantitative studies that analyzed the typical imaging findings related to BRONJ. Further studies are necessary in order to analyze the role of different imaging techniques in the assessment of BRONJ.

Basic research and clinical applications of bisphosphonates in bone disease: what have we learned over the last 40 years?

It is now 40 years since bisphosphonates (BPs) were first used in the clinic. So, it is timely to provide a brief review of what we have learned about these agents in bone disease. BPs are bone-specific and have been classified into two major groups on the basis of their distinct molecular modes of action: amino-BPs and non-amino-BPs. The amino-BPs are more potent and they inhibit farnesyl pyrophosphate synthase (FPPS), a key enzyme of the mavalonate/cholesterol biosynthetic pathway, while the non-amino-BPs inhibit osteoclast activity, by incorporation into non-hydrolyzable analogs of ATP. Both amino-BPs and non-amino-BPs can protect osteoblasts and osteocytes against apoptosis. The BPs are widely used in the clinic to treat various diseases characterized by excessive bone resorption, including osteoporosis, myeloma, bone metastasis, Legg-Perthes disease, malignant hyperparathyroidism, and other conditions featuring bone fragility. This review provides insights into some of the adverse effects of BPs, such as gastric irritation, osteonecrosis of the jaw, atypical femoral fractures, esophageal cancer, atrial fibrillation, and ocular inflammation. In conclusion, this review covers the biochemical and molecular mechanisms of action of BPs in bone, particularly the discovery that BPs have direct anti-apoptotic effects on osteoblasts and osteocytes, and the current situation of BP use in the clinic.