Management of osteoradionecrosis of the jaws: An analysis of evidence

A Compromised Maxillofacial Wound Healing Model for Characterization of Particulate Bone Grafting: An In Vivo Study in Rabbits

Preclinical testing of tissue engineering modalities are commonly performed in a healthy wound bed. These conditions do not represent clinically relevant compromised oral wound environments due to radiation treatments seen clinically. This study aimed to characterize the bone regeneration outcomes in critical-sized mandibular defects using particulate grafting in an irradiated preclinical model of compromised wound healing. Sixteen New Zealand white rabbits were divided into two groups (n = 8/group), namely (i) irradiated (experimental) and (ii) non-irradiated (control). The rabbits in the experimental group received a total of 36 Gy radiation, followed by surgical intervention to create critical-sized (10 mm), full-thickness mandibular defects. The control group was subjected to the same surgical intervention. All defects were filled with bovine bone grafting material (Bio-Oss, Geistlich, Princeton, NJ, USA) and allowed to heal for 8 weeks. At the study endpoint, rabbits were euthanized, and their mandibles were harvested for micro-computed tomographic, histological, and histomorphometric processing and analysis. Qualitative histological analysis revealed increased levels of bone formation and bridging in the control group relative to the experimental group. This was accompanied by increased levels of soft tissue presence in the experimental group. Volumetric reconstruction showed a significantly higher degree of bone in the control group (27.59% ± 2.71), relative to the experimental group (22.02% ± 2.71) (p = 0.001). The irradiated rabbit model exhibited decreased bone regeneration capacity relative to the healthy subjects, highlighting its suitability as a robust compromised wound healing environment for further preclinical testing involving growth factors or customized, high-fidelity 3D printed tissue engineering scaffolds.

Occurrence of Jaw Osteonecrosis and Frequency of Prophylactic Tooth Extractions Prior to Head and Neck Radiotherapy: A Retrospective Study of 497 Irradiated Patients

Background/Objectives: This retrospective study examined the relationship between prophylactic tooth extraction (PTE) and the occurrence of jaw osteoradionecrosis (JORN) in patients undergoing head and neck radiotherapy (HNR). The primary objective was to determine whether PTE resulted in a JORN rate comparable to that of patients who did not require or undergo PTE. Methods: A total of 497 patients were included. The primary predictor variable was PTE, and the primary outcome was JORN occurrence. Statistical analyses included univariate, bivariate, and multivariate regression, as well as Cox regression. The significance threshold was set at p ≤ 0.005. Results: JORN was more frequent in the PTE group than in patients who did not require or undergo PTE (17.1% vs. 13.0%; hazard ratio [HR] 1.71, 95% CI: 1.08-2.71, p = 0.021). However, a significant association could not be confirmed using multiple logistic regression (odds ratio [OR] 1.36, 95% CI: 0.82-2.26, p = 0.236). Suggestive associations were observed for HNR dose (HR 1.03 per Gy, p = 0.007) and tumor location (pharyngeal HR 0.52, p = 0.03; laryngeal HR 0.51, p = 0.02). Conclusions: Patients with PTE showed a higher JORN rate but the findings were only marginally significant, and no causal relationship was established. The differing results between Cox and logistic regression suggest a time-dependent effect of PTE, with an increased early risk for JORN. Further studies are needed to determine whether greater emphasis should be placed on tooth-preserving measures, limiting extractions before HNR to strictly non-preservable teeth.

Hyperbaric Oxygen Therapy for the Treatment of Bone-Related Diseases

Hyperbaric oxygen therapy (HBOT) is a therapeutic modality that enhances tissue oxygenation by delivering 100% oxygen at pressures greater than 1 absolute atmosphere. In recent years, HBOT has shown considerable potential in the treatment of bone diseases. While excess oxygen was once thought to induce oxidative stress, recent studies indicate that when administered within safe limits, HBOT can notably promote bone healing and repair. Extensive basic research has demonstrated that HBOT can stimulate the proliferation and differentiation of osteoblasts and encourage bone angiogenesis. Furthermore, HBOT has been shown to exert a beneficial influence on bone metabolism by modulating the inflammatory response and redox status. These mechanisms are closely related to core issues of bone biology. Specifically, in the context of fracture healing, bone defect repair, and conditions such as osteoporosis, HBOT targets the key bone signaling pathways involved in bone health, thereby exerting a therapeutic effect. Several clinical studies have demonstrated the efficacy of HBOT in improving bone health. However, the optimal HBOT regimen for treating various bone diseases still requires further definition to expand the indications for its clinical application. This paper outlines the mechanisms of HBOT, focusing on its antioxidant stress, promotion of bone vascularization, and anti-inflammatory properties. The paper also describes the application of HBOT in orthopedic diseases, thereby providing a scientific basis for the development of precise and personalized HBOT treatment regimens in clinical orthopedics.

Cluster-Based Toxicity Estimation of Osteoradionecrosis Via Unsupervised Machine Learning: Moving Beyond Single Dose-Parameter Normal Tissue Complication Probability by Using Whole Dose-Volume Histograms for Cohort Risk Stratification

PURPOSE

Given the limitations of extant models for normal tissue complication probability estimation for osteoradionecrosis (ORN) of the mandible, the purpose of this study was to enrich statistical inference by exploiting structural properties of data and provide a clinically reliable model for ORN risk evaluation through an unsupervised-learning analysis that incorporates the whole radiation dose distribution on the mandible.

METHODS AND MATERIALS

The analysis was conducted on retrospective data of 1259 patients with head and neck cancer treated at The University of Texas MD Anderson Cancer Center between 2005 and 2015. During a minimum 12-month posttherapy follow-up period, 173 patients in this cohort (13.7%) developed ORN (grades I to IV). The (structural) clusters of mandibular dose-volume histograms (DVHs) for these patients were identified using the K-means clustering method. A soft-margin support vector machine was used to determine the cluster borders and partition the dose-volume space. The risk of ORN for each dose-volume region was calculated based on incidence rates and other clinical risk factors.

RESULTS

The K-means clustering method identified 6 clusters among the DVHs. Based on the first 5 clusters, the dose-volume space was partitioned by the soft-margin support vector machine into distinct regions with different risk indices. The sixth cluster entirely overlapped with the others; the region of this cluster was determined by its envelopes. For each region, the ORN incidence rate per preradiation dental extraction status (a statistically significant, nondose related risk factor for ORN) was reported as the corresponding risk index.

CONCLUSIONS

This study presents an unsupervised-learning analysis of a large-scale data set to evaluate the risk of mandibular ORN among patients with head and neck cancer. The results provide a visual risk-assessment tool for ORN (based on the whole DVH and preradiation dental extraction status) as well as a range of constraints for dose optimization under different risk levels.

Role of Photodynamic Therapy in Osteonecrosis and Osteoradionecrosis of the Jaws: A Systematic Review

Aim

Photodynamic therapy (PDT) is a minimally invasive treatment modality that has been used clinically for early stage and inoperable cancers. Successful use of this atraumatic therapy in osteoradionecrosis (ORN) and osteonecrosis of the jaws (ONJ) has been documented in the literature. The aim of this review was to systematically evaluate the role of photodynamic therapy in ORN and ONJ.

Methods

Two independent reviewers conducted an elaborate search in PubMed, Google Scholar and Cochrane's CENTRAL database for studies published on PDT as stand-alone or adjuvant therapy in ORN/ONJ until June 2022. The present study was based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Demographic data, type and stage of necrosis of the jaws, site, PDT protocol, time to heal and follow-up were evaluated. Eighteen articles were included totally based on the inclusion and exclusion criteria for final analysis.

Results

A total of 94 patients were included in the present review out of which 36 were males and 58 were females. Five studies reported the use of PDT as an adjuvant therapy in ORN. Thirteen studies reported successful outcomes with PDT in ONJ. Complete epithelialization was achieved with PDT ± other adjuvants in 86/94 (91.48%) patients. The time taken for regression of the lesion ranged between 4 days and 12 months with PDT in the present study.

Conclusion

The reviewed studies demonstrate the effectiveness of PDT, as an adjuvant therapy, in managing various stages of ORN and ONJ.

The added values of 18F-FDG PET/CT in differentiating cancer recurrence and osteoradionecrosis of mandible in patients with treated oral squamous cell carcinoma

BACKGROUND

Osteoradionecrosis (ORN) of the jaw requires a differential diagnosis to exclude cancer recurrence. Here, we sought to develop a scoring system comprising ¹⁸F-FDG PET/CT parameters for distinguishing between the two conditions in patients with oral squamous cell carcinoma (OSCC).

METHODS

The study consisted of 103 OSCC patients with suspected ORN of the jaw. All participants underwent ¹⁸F-FDG PET/CT imaging within 6 months of diagnostic histopathology. Following extraction of PET parameters, we identified clinical and imaging predictors of mandibular recurrence-free survival (MRFS) using receiver operating characteristic curve analysis and multivariate Cox regression models.

RESULTS

The results of histopathology revealed mandibular cancer recurrence in 24 patients (23.3%). Multivariate Cox regression analyses identified an age at diagnosis ≤ 52 years (P = 0.013), a location of the SUVmax voxel with soft tissue predominance (P = 0.019), and mandibular total lesion glycolysis (TLG) > 62.68 g (P < 0.001) as independent risk factors for MRFS. A scoring system was devised with scores from 0 (no risk factor) to 3 (presence of all three risk factors). High-risk patients with a score of 2-3 compared with score of 0-1 had a significantly higher likelihood of mandibular cancer recurrence (hazard ratio: 32.50, 95% confidence interval: 8.51-124.18, P < 0.001). The scoring system had a sensitivity of 87.50%, a specificity of 82.28%, and an accuracy of 83.50% for identifying mandibular cancer recurrence.

CONCLUSIONS

The scoring system of our study is clinically useful for identifying mandibular cancer recurrence in patients with suspected ORN of the jaw.

Cluster-Based Toxicity Estimation of Osteoradionecrosis via Unsupervised Machine Learning: Moving Beyond Single Dose-Parameter Normal Tissue Complication Probability by Using Whole Dose-Volume Histograms for Cohort Risk Stratification

Purpose

Given the limitations of extant models for normal tissue complication probability estimation for osteoradionecrosis (ORN) of the mandible, the purpose of this study was to enrich statistical inference by exploiting structural properties of data and provide a clinically reliable model for ORN risk evaluation through an unsupervised-learning analysis.

Materials and Methods

The analysis was conducted on retrospective data of 1,259 head and neck cancer (HNC) patients treated at the University of Texas MD Anderson Cancer Center between 2005 and 2015. The (structural) clusters of mandibular dose-volume histograms (DVHs) were identified through the K-means clustering method. A soft-margin support vector machine (SVM) was used to determine the cluster borders and partition the dose-volume space. The risk of ORN for each dose-volume region was calculated based on the clinical risk factors and incidence rates.

Results

The K-means clustering method identified six clusters among the DVHs. Based on the first five clusters, the dose-volume space was partitioned almost perfectly by the soft-margin SVM into distinct regions with different risk indices. The sixth cluster overlapped the others entirely; the region of this cluster was determined by its envelops. These regions and the associated risk indices provide a range of constraints for dose optimization under different risk levels.

Conclusion

This study presents an unsupervised-learning analysis of a large-scale data set to evaluate the risk of mandibular ORN among HNC patients. The results provide a visual risk-assessment tool (based on the whole DVH) and a spectrum of dose constraints for radiation planning.

Merits of the free periosteal femoral condyle flap in the management of advanced mandibular osteoradionecrosis

The management of advanced mandibular osteoradionecrosis (ORN) is poorly codified and requires repeated time-consuming, morbid surgical procedures. The free periosteal medial femoral condyle flap could be used for the management of extensive mandibular ORN with fracture, to avoid non-conservative surgery such as mandibulectomy. The purpose of this study was to report the authors' experience using periosteal flaps for advanced ORN and to assess the therapeutic effectiveness of these flaps in this context. A series of 10 patients who underwent bone revascularization with a free periosteal femoral flap for the management of advanced ORN (Notani class III) is reported. The onset of bone consolidation, length of hospital stay, duration of surgery, donor site morbidity, and the option of dental rehabilitation in the event of a successful outcome were assessed. Osteogenesis was observed in 70% of cases. Thirty percent of patients benefited from dental implant rehabilitation. The mean follow-up was 73.1 months. No patient experienced any sequelae at the flap harvest site. In the authors' opinion, the free periosteal medial femoral condyle flap appears to offer a therapeutic solution for patients with advanced stages of ORN.

Cell death mechanisms in head and neck cancer cells in response to low and high-LET radiation

Head and neck squamous cell carcinoma (HNSCC) is a common malignancy that develops in or around the throat, larynx, nose, sinuses and mouth, and is mostly treated with a combination of chemo- and radiotherapy (RT). The main goal of RT is to kill enough of the cancer cell population, whilst preserving the surrounding normal and healthy tissue. The mechanisms by which conventional photon RT achieves this have been extensively studied over several decades, but little is known about the cell death pathways that are activated in response to RT of increasing linear energy transfer (LET), including proton beam therapy and heavy ions. Here, we provide an up-to-date review on the observed radiobiological effects of low- versus high-LET RT in HNSCC cell models, particularly in the context of specific cell death mechanisms, including apoptosis, necrosis, autophagy, senescence and mitotic death. We also detail some of the current therapeutic strategies targeting cell death pathways that have been investigated to enhance the radiosensitivity of HNSCC cells in response to RT, including those that may present with clinical opportunities for eventual patient benefit.

Overview and Emerging Trends in the Treatment of Osteoradionecrosis

OPINION STATEMENT

Osteoradionecrosis (ORN) of the mandible is a rare but devastating complication which occurs following radiation therapy for head and neck malignancies. Left untreated, ORN often results in pathologic fracture of the mandible leading to pain, trismus, difficulty eating, and overall poor quality of life. Historically, early intervention relied on hyperbaric oxygen and local debridement. Patients whose disease progressed despite therapy required segmental resection of the mandible with osseous free flap reconstruction, a highly invasive operation. Patients that presented with a moderate disease without pathologic fracture were often doomed to fail non-operative management, ultimately leading to disease progression and fracture. The traditional dichotomous treatment paradigm left a void of options for patients with moderate disease. The ideal intervention for this category of patients would provide renewed vascularity to the diseased tissue bed allowing for the osteogenesis and reestablishment of strong, load-bearing bone. The innovative technique termed the vascularized fascia lata "rescue flap" has proven to be an effective treatment for moderate ORN and will likely transform dated treatment algorithms.

Surgical Management of Skull Base Osteoradionecrosis in the Cancer Population - Treatment Outcomes and Predictors of Recurrence: A Case Series

BACKGROUND

Skull base osteoradionecrosis (ORN) is a challenging treatment-related complication sometimes seen in patients with cancer. Although ORN management strategies for other anatomic sites have been reported, there is a paucity of data guiding the management of skull base ORN.

OBJECTIVE

To report a single-center tertiary care series of skull base ORN and to better understand the factors affecting ORN recurrence after surgical management.

METHODS

We conducted a retrospective cohort study of patients with skull base ORN treated at our center between 2003 and 2017. Univariate and multivariate binary logistic regressions were performed to identify predictors of recurrence.

RESULTS

A total of 31 patients were included in this study. The median age at ORN diagnosis was 61.1 yr (range, 32.8-84.9 yr). Of these 31 patients, 15 (48.4%) patients were initially treated medically. All 31 patients underwent surgery. Three (14.3%) of 21 patients treated with a free flap and 4 (50.0%) of 8 patients who underwent primary closure experienced recurrence. Cox regression analysis revealed that reconstruction with local tissue closure (P = .044) and ongoing treatment for active primary cancer (P = .022) were significant predictors of recurrence. The median overall survival from index surgery for ORN treatment was 83.9 mo. At 12-mo follow-up, 78.5% of patients were alive.

CONCLUSION

In this study, we assess the outcomes of our treatment approach, surgical debridement with vascularized reconstruction, on recurrence-free survival in patients with skull base ORN. Further studies with larger cohorts are needed to assess current treatment paradigms.

Practical Approach to Radiopaque Jaw Lesions

Radiopaque lesions of the jaw are myriad in type and occasionally protean in appearance. In turn, the radiologic analysis of these lesions requires a systematic approach and a broad consideration of clinical and imaging characteristics to enable reliable radiologic diagnosis. Initially categorizing lesions by attenuation pattern provides a practical framework for organizing radiopaque jaw lesions that also reflects important tissue characteristics. Specifically, the appearance of radiopaque lesions can be described as (a) densely sclerotic, (b) ground glass, or (c) mixed lytic-sclerotic, with each category representing a distinct although occasionally overlapping differential diagnosis. After characterizing attenuation pattern, the appreciation of other radiologic features, such as margin characteristics or relationship to teeth, as well as clinical features including demographics and symptoms, can aid in further narrowing the differential diagnosis and lend confidence to clinical decision making. The authors review the potential causes of a radiopaque jaw lesion, including pertinent clinical and radiologic features, and outline a simplified approach to its radiologic diagnosis, with a focus on cross-sectional CT. An invited commentary by Buch is available online. ^©RSNA, 2021.

Impaired Callus Formation in Pathological Mandibular Fractures in Medication-Related Osteonecrosis of the Jaw and Osteoradionecrosis

PURPOSE

Nonsurgical treatment of mandibular fractures secondary to medication-related osteonecrosis of the jaw (MRONJ) or osteoradionecrosis (ORN) mostly results in nonunion, whereas nonsurgical fracture treatment of atrophic fractures can achieve favorable results in selected cases. The aim of this study was to compare callus formation in pathological mandibular fractures due to MRONJ, ORN, or extreme mandibular atrophy.

METHODS

A retrospective cohort study reviewing the medical records of all MRONJ-, ORN-, or atrophy-related fractures treated at the departments of maxillofacial surgery in the Leuven or Lille university hospitals between 2010 and 2019 was undertaken. The primary predictor variable in this study was disease state (MRONJ, ORN, or extreme mandibular atrophy). The primary outcome variable was callus formation after 1 month of follow-up (present, absent). Additional study variables measured included patient age and gender. T-tests, Fisher exact tests, and multiple logistic regression were used for statistical analysis. The significance level was set at P < .05.

RESULTS

Seventy patients were analyzed (12 MRONJ cases, 54 ORN fractures, 4 atrophic fractures). The callus formation prevalence in nonsurgically approached fractures secondary to ORN and MRONJ after 1 month of follow-up was 3.03% (2/66 cases). In contrast, callus was detected in all patients in the mandibular atrophy-related fracture group. Osteonecrosis was statistically correlated with impaired callus formation (P = .0121).

CONCLUSION

Whereas one would expect indirect fracture healing and thus callus formation to occur in all non-surgically treated fractures, our data demonstrate its absence in the majority of MRONJ- and ORN-related fractures. Multiple plausible explanations for this phenomenon were identified: periosteal damage with loss of callus-forming cells, compromised vasculature, and bacterial colonization.

The Role of Hyperbaric Oxygen in Head and Neck Reconstruction and Facial Cosmetic Surgery

Hyperbaric oxygen (HBO) is a treatment modality with the primary mechanism of therapy being the delivery of oxygen to hypoxic tissues. A review of HBO applications in the field of head and neck reconstruction and facial cosmetic surgery is provided. HBO can be useful in the management of radiation sequelae and treatment of compromised flaps and grafts. It may also have application in tissue compromise following cosmetic surgery and dermal fillers. We provide evidence from the available literature as well as highlight our experience in using HBO in head and neck reconstruction.

Skeletal Stem Cells-A Paradigm Shift in the Field of Craniofacial Bone Tissue Engineering

Defects of the craniofacial skeleton arise as a direct result of trauma, diseases, oncological resection, or congenital anomalies. Current treatment options are limited, highlighting the importance for developing new strategies to restore form, function, and aesthetics of missing or damaged bone in the face and the cranium. For optimal reconstruction, the goal is to replace "like with like." With the inherent challenges of existing options, there is a clear need to develop alternative strategies to reconstruct the craniofacial skeleton. The success of mesenchymal stem cell-based approaches has been hampered by high heterogeneity of transplanted cell populations with inconsistent preclinical and clinical trial outcomes. Here, we discuss the novel characterization and isolation of mouse skeletal stem cell (SSC) populations and their response to injury, systemic disease, and how their re-activation in vivo can contribute to tissue regeneration. These studies led to the characterization of human SSCs which are able to self-renew, give rise to increasingly fate restricted progenitors, and differentiate into bone, cartilage, and bone marrow stroma, all on the clonal level in vivo without prior in vitro culture. SSCs hold great potential for implementation in craniofacial bone tissue engineering and regenerative medicine. As we begin to better understand the diversity and the nature of skeletal stem and progenitor cells, there is a tangible future whereby a subset of human adult SSCs can be readily purified from bone or activated in situ with broad potential applications in craniofacial tissue engineering.

Pentoxifylline, tocopherol, and sequestrectomy are effective for the management of advanced osteoradionecrosis of the jaws-a case series

BACKGROUND

The aim of the present study was to evaluate the efficacy of pentoxifylline and tocopherol for the management of osteoradionecrosis of the jaws.

METHODS

Twenty-five patients diagnosed with osteoradionecrosis of the jaws treated with pentoxifylline 400 mg + tocopherol 400 mg three times daily (tid) were evaluated. Clinical records and image tests were reviewed. All patients were previously submitted to head and neck radiation therapy and presented with a clinical and radiographic diagnosis of osteoradionecrosis of the jaws.

RESULTS

Following therapy with pentoxifylline and tocopherol, 76% (19/25) of the patients showed complete mucosal healing, in which 47.3% (9/19) did not undergo sequestrectomy. From this particular group, 77.7% (7/9) were in stage I and 33.3% (3/9) used the protocol for up to 3 months. Among those who underwent to sequestrectomy, complete mucosal healing was observed in 52.7% (10/19). Among these, 60% (6/10) were in stage I and 100% of the patients were using the protocol for more than 3 months. In all other patients, partial healing of the mucosa was observed since they presented advanced disease. These represented 24% of the sample (6/25), 66.6% (4/6) were in stage III, and 60% (4/6) used the protocol for over 6 months.

CONCLUSION

Pentoxifylline and tocopherol may provide effective management of osteoradionecrosis of the jaws, and the association with sequestrectomy may avoid major surgical procedures.

Dental prevention of maxillo-mandibular osteoradionecrosis: A ten-year retrospective study

INTRODUCTION

Osteoradionecrosis (ORN) remains a frequent complication of radiotherapy in head and neck cancer. As ORN management is often complex, it is essential to focus on its prevention, mainly by dental prophylaxis. The objectives of this study were to evaluate a dental preventive approach based on ORN data and to highlight individual risk factors statistically associated with time-to-ORN.

MATERIALS AND METHODS

A retrospective study (January 2004-December 2013) included 415 patients with head and neck cancer who received radiotherapy in their treatment with at least 50 Grays on maxillo-mandibular bones. Pre-radiotherapy dental assessment (clinical and radiological) and prevention (with standardised extraction protocol) were performed.

RESULTS

The ORN rate was 7.5%, with a dental origin in 35.5% of cases, mainly represented by dental infection in exclusive mandibular locations. More than 90% of patients were partially or completely dentate, and more than 70% had poor oral hygiene. Dental extractions were performed in 67.9% of patients before radiotherapy and in 42.9% after radiotherapy. Statistically significant risk factors associated with time-to-ORN were addictions (tobacco and alcohol), diabetes, oropharyngeal tumour location, combination of surgery followed by radiotherapy and post-radiotherapy dental extractions.

DISCUSSION AND CONCLUSION

Considering that ORN implies severe disabilities and complex management, the rate of 7.5% is unacceptable. A better dental prevention could reduce this rate by one-third. Dental extractions could be systematic in high-dose irradiation mandibular areas in patients presenting with poor oral hygiene and/or statistically significant risk factors for the occurrence of ORN. Moreover, favourable oral condition after radiotherapy should be maintained.

Research Frontiers in Oral Toxicities of Cancer Therapies: Osteoradionecrosis of the Jaws

The deleterious effects of head and neck radiation on bone, with osteoradionecrosis (ORN) as the major disabling side effect of head and neck cancer treatment, are difficult to prevent and hard to treat. This review focuses on the current state of the science regarding the pathobiology, clinical impact, and management of ORN. With regard to the pathobiology underlying ORN, it is not yet confirmed whether the current radiation schedules by 3-dimensional conformal radiotherapy and intensity modified radiotherapy result in an unchanged, decreased, or increased risk of developing ORN when compared with conventional radiation treatment, the main risk factor being the total radiation dose delivered on any clinically significant surface of the mandible.

With regard to the prevention of ORN, a thorough, early pre-irradiation dental assessment is still considered the first step to reduce the hazard of developing ORN post-radiotherapy, and hyperbaric oxygen (HBO) treatment reduces the risk of developing ORN in case of dental surgery in an irradiated field.

With regard to the treatment of ORN, the focus is bidirectional: elimination of the necrotic bone and improving the vascularity of the normal tissues that were included in the radiation portal. The cure rate of limited ORN by conservative therapy is approximately 50%, and the cure rate of surgical approaches when conservative therapy has failed is approximately 40%.

Whether it is effective to support conservative or surgical treatment with HBO as an adjuvant is not set. HBO treatment is shown to increase the vascularity of hard and soft tissues and has been reported to be beneficial in selected cases. However, in randomized clinical trials comparing the preventive effect of HBO on developing ORN with, eg, antibiotic coverage in patients needing dental surgery, the preventive effect of HBO was not shown to surpass that of a more conservative approach.

More recently, pharmacologic management was introduced in the treatment of ORN with success, but its efficacy has to be confirmed in randomized clinical trials. The major problem of performing well-designed randomized clinical trials in ORN is having access to large numbers of patients with well-defined, comparable cases of ORN. Because many institutions will not have large numbers of such ORN cases, national and international scientific societies must be approached to join multicenter trials. Fortunately, the interest of funding organizations and the number researchers with an interest in healthy aging is growing. Research aimed at prevention and reduction of the morbidity of cancer treatment fits well within these programs.

Management of incidental discovery of microscopic squamous cell carcinoma in zones of osteoradionecrosis of the mandible

OBJECTIVES

Osteoradionecrosis (ORN) of the mandible is a common complication of head and neck radiotherapy and often requires surgical treatment. Squamous cell carcinoma (SCC) can be exceptionally discovered within zones of ORN on histological examination of the operative specimen. The authors discuss the management of these lesions based on a short patient series.

MATERIALS AND METHODS

This single-centre retrospective study was based on patients managed between 2012 and 2014 for ORN with incidental discovery of microscopic SCC.

RESULTS

Five patients with incidental discovery of microscopic SCC in a zone of ORN of the mandible were included in this study. The mean time to onset of ORN after the end of radiotherapy for locally advanced SCC of the oral cavity or oropharynx was 42 months. Surgical treatment consisted of marginal or segmental mandibulectomy with free flap reconstruction. No recurrence was observed with a mean follow-up of 35 months [24-46].

CONCLUSION

The incidental discovery of microscopic SCC in a zone of ORN of the mandible is a rare event and has not been reported in the literature. Optimal management cannot be reliably defined due to the lack of data in the literature, but the present study supports careful histological examination of ORN specimens. Treatment must be as conservative as possible to avoid excessively invasive surgery.

Effect of Irrigation Time of Antiseptic Solutions on Bone Cell Viability and Growth Factor Release

Antiseptic solutions are commonly utilized to treat local infection in the oral and maxillofacial region. However, surrounding vital bone is also exposed to antiseptic agents during irrigation and may have a potential negative impact on bone survival. The aim of the present study was therefore to investigate the effect of rinsing time with various antiseptic solutions on bone cell viability, as well as their subsequent release of growth factors important for bone regeneration. The bone samples collected from porcine mandible were rinsed in the following commonly utilized antiseptic solutions; povidone-iodine (0.5%), chlorhexidine digluconate (CHX, 0.2%), hydrogen peroxide (1%), and sodium hypochlorite (0.25%) for 1, 5, 10, 20, 30, or 60 minutes and assessed for cell viability and release of growth factors including vascular endothelial growth factor, transforming growth factor beta 1, bone morphogenetic protein 2, receptor activator of nuclear factor kappa-B ligand, and interleukin-1 beta by enzyme-linked immunosorbent assay. It was found in all the tested groups that the long exposure of any of the tested antiseptic solutions drastically promoted higher cell death. Sodium hypochlorite demonstrated the significantly highest cell death and at all time points. Interestingly, bone cell viability was highest in the CHX group post short-term rinsing of 1, 5, or 10 minutes when compared with the other 4 tested groups. A similar trend was also observed in subsequent growth factor release. The present study demonstrated that of the 4 tested antiseptic solutions, short-term CHX rinsing (ideally within 1 minute) favored bone cell viability and growth factor release. Clinical protocols should be adapted accordingly.

Successful treatment of grade III osteoradionecrosis with mandibular fracture with pentoxifylline, tocopherol and clodronate

Osteoradionecrosis (ORN) is one of the most severe complications after head and neck radiotherapy. Once established, ORN is difficult to manage and is traditionally considered to be irreversible. Since the recent understanding of the pathophysiology of ORN is based on the concept of radiation-induced fibrosis, a new therapeutic medical regimen has been proposed comprising the combination of pentoxifylline, tocopherol and clodronate (PENTOCLO). A 55-year-old woman presented with grade III ORN with large intraoral bone exposure, a fracture of the left posterior horizontal branch and an orocutaneous fistula. Because she refused surgery, medical treatment with PENTOCLO was proposed. After 55months of treatment, there was complete mucosal coverage and complete consolidation of the fracture site around the orocutaneous fistula. PENTOCLO treatment can help some patients with grade III disease, as in this case. Further prospective randomized controlled trials are needed to confirm this result.

Teriparatide therapy for severe, refractory osteoradionecrosis of the jaw

Although osteoradionecrosis (ORN) is a serious complication of craniofacial radiotherapy, the current management methods remain suboptimal. Teriparatide (TPTD), a recombinant human parathyroid hormone (1-34), has shown beneficial effects on osseous regeneration in medication-related osteonecrosis of the jaw or periodontitis. However, TPTD therapy in irradiated bones has not been indicated yet because of the theoretical risk of osteosarcoma seen in rat models. Hence, we first report here two patients with tongue cancer with late-emerging ORN who were successfully treated with TPTD for 4-6 months with serum calcium and vitamin D supplementation. In contrast to the usual progress of ORN, the bone defect regenerated well and bone turnover markers including serum C-terminal telopeptide of type 1 collagen and osteocalcin were restored with TPTD therapy. Our experience might suggest that TPTD therapy with careful monitoring can provide an effective treatment option for patients with ORN in select refractory cases, with the benefits outweighing the potential risks.

Using the Nasoseptal Flap for Reconstruction after Endoscopic Debridement of Radionecrosis in Nasopharyngeal Carcinoma

Background

Radionecrosis is a complication of nasopharyngeal carcinoma (NPC) that is difficult to treat. Endoscopic debridement is the first-line treatment for radionecrosis. After debridement, however, either bone or the internal carotid artery is exposed and requires mucosal coverage.

Objectives

This study sought to demonstrate the effectiveness of a nasoseptal flap (NSF) after endoscopic debridement of radionecrosis in the reconstruction ofnasopharyngeal or skull base defects.

Methods

Nine patients with NPC who underwent navigation-guided endoscopic debridement, followed by NSF reconstruction between April 2013 and July 2016, were included. The patients' clinical features and outcomes were evaluated.

Results

All nine patients had headaches, and eight had a foul odor associated with their radionecrosis. One patient underwent three radiotherapy treatments, four had two treatments, and the remaining four had just one treatment. The foul odor disappeared after treatment in all the patients who had been affected. The headache was significantly reduced after treatment in all patients. The NSF detached in two patients. In one patient, NSF failed, and the patient experienced postoperative rupture of the internal carotid artery. In the seven other patients, the NSF successfully covered the resultant defects, despite one intraoperative internal carotid artery rupture. Only two patients required further debridement, whereas the others experienced complete healing after just one surgical procedure. The nasopharyngeal surface was healthy-appearing in eight patients (median follow-up, median 11 months).

Conclusion

Reconstruction by using NSF after endoscopic debridement for radionecrosis of NPC allowed for faster healing and reduced the need for further debridement.

Predictive factors for osteoradionecrosis of the jaws: A retrospective study

BACKGROUND

Osteoradionecrosis of the jaw (ORNJ) is a well-recognized complication of radiotherapy. The purpose of this study was to assess predictive factors for the development of ORNJ.

METHODS

A retrospective study of 325 patients with head and neck squamous cell carcinoma (HNSCC) treated at one institution between January 1, 1999, and December 31, 2008, was conducted. Outcome measure was the presence/absence of ORNJ. Time to event was recorded and Cox proportional hazard regression analysis was used to determine statistically significant predictive factors.

RESULTS

Fifty-nine patients had ORNJ. Statistical analysis using Cox regression analysis identified several statistically significant variables: dentoalveolar surgery; peri-resective surgery of the jaw; continued tobacco usage after radiotherapy, diabetes mellitus type 2 (DM2); and total radiation dose.

CONCLUSION

Patients at greater risk of developing ORNJ can be identified and measures can be instituted to reduce its incidence and expedite management when it does occur.

Chemical and Radiation-Associated Jaw Lesions

Osteonecrosis of the jaw is a major public health concern throughout the world. Use of radiotherapy for head and neck cancer and bone antiresorptives and antiangiogenic agents have increased its incidence. Medication-related osteonecrosis of the jaw is more common relative to other types of osteonecrosis. Osteoradionecrosis occurs despite better treatment planning and shielding to minimize collateral damage to bone. Other related necrotic lesions are secondary to usage of recreational drugs and steroids. This article provides comprehensive information about these different types of bone necrosis; provides the readers with radiographic diagnostic criteria and updates on current theories on pathophysiology of osteonecrosis.

Osteoradionecrosis of the jaws: definition, epidemiology, staging and clinical and radiological findings. A concise review

Osteoradionecrosis (ORN) of the jaws is a pernicious complication of radiation therapy for head and neck tumours. This article aims to provide an update on data related to the definition, epidemiology, staging, and clinical and radiological findings of ORN of the jaws. Using certain keywords, an electronic search was conducted spanning the period from January 1922 to April 2014 to identify the available related investigations. Pooled data were then analysed. ORN is described as exposed irradiated bone that fails to heal over a period of 3 months without evidence of persisting or recurrent tumour. The prevalence of ORN varies in the literature. Several staging or scoring systems of ORN have been proposed. Clinical findings include ulceration or necrosis of the mucosa with exposure of necrotic bone. Radiological findings are not evident in the early stages of ORN. Furthermore ORN may not be apparent in imaging even when the disease is advanced. Taking into account the severity of ORN and the difficulties in diagnosing it early and accurately, the clinician should be aware of this complex entity in order to prevent its appearance or the development of more severe complications.

Cost analysis of osteoradionecrosis

Objective:

Osteoradionecrosis is a significant complication of head and neck cancer treatment, and its most severe form (grade III) necessitates radical surgery. This study aimed to compare the cost of free-flap reconstructive surgery for grade III osteoradionecrosis and similar non-osteoradionecrosis cases in order to assess the cost burden of osteoradionecrosis treatment.

Methods:

All patients who underwent free-flap reconstructive surgery for osteoradionecrosis between July 2004 and July 2010 at Auckland City Hospital (19 patients) were identified, and relevant data were collected retrospectively. These patients were matched in terms of age and sex with patients who underwent free-flap reconstructive surgery.

Results:

The treatment cost was 44 per cent higher in osteoradionecrosis patients when compared to non-osteoradionecrosis patients.

Conclusion:

The significant financial burden on the health system, and the growing evidence for the effectiveness of pentoxifylline, tocopherol and clodronate, should prompt us to explore this alternative treatment further.

Metastatic gastric tube cancer detected in a resected mandibular bone with osteoradionecrosis

Osteoradionecrosis (ORN) of the jaw is an intractable complication of radiotherapy for head and neck cancer. However, osteolytic lesions are often hard to distinguish from malignancies. We report a rare case of metastatic cancer in a resected mandibular bone after segmental resection for ORN of the jaw. A 63-year-old male with a history of subtotal oesophageal resection for oesophageal cancer and reconstruction of the oesophagus with a gastric tube subsequently developed ORN of the jaw. Conservative treatment was unsuccessful and pathological fracture of the necrotic mandible occurred. The patient underwent segmental resection of the mandible and adenocarcinoma was detected in the resected mandibular bone. Immunohistochemical staining for cytokeratin 7 and 20 revealed that the adenocarcinoma had metastasized from the reconstructed gastric tube. This case highlights the fact that cancers of the gastric tube may metastasize to radiation-induced necrotic bone tissue in the mandible.

Osteoradionecrosis of the Posterior Maxilla: A New Approach Combining Erbium: Yttrium Aluminium Garnet Laser and Bichat Bulla Flap

Osteoradionecrosis (ORN) of the jaw is a complication of radiation therapy for head and neck cancers. We report a case of ORN of the posterior maxilla treated with Er: YAG laser and a pedicled buccal fat pad (bichat bulla adipose) flap. A 69-year-old man presented complaining of pain on left maxilla. He had received high-dose radiotherapy (90 Gy) for squamous cell carcinoma of the left soft palate 2 years earlier. Clinical and radiographic examinations revealed ORN of the left maxillary molar region and maxillary sinusitis. Daily home care consisted of 0.9% saline irrigation and 0.8% H2O2 gel application. Sequestrectomy and tooth extraction were followed by debridement with Er: YAG laser and repair with a pedicled buccal fat pad flap. Complete resolution of ORN and maxillary sinusitis was established one year postsurgically. The excellent clinical outcome suggests that Er: YAG laser debridement and pedicled buccal fat pad flap are a viable option to treat ORN of the posterior maxilla.

An Athymic Rat Model for Mandibular Osteoradionecrosis Allowing for Direct Translation of Regenerative Treatments

Objective

We aim to create a model of mandibular osteoradionecrosis in athymic rats. Athymic rats provide an immunosuppressed environment whereby human stem cells and biomaterials can be used to investigate regenerative solutions for osteoradionecrosis, bridging the gap between in vivo testing and clinical application.

Study Design

Prospective animal study.

Setting

Academic otolaryngology department laboratory.

Subjects and Methods

After Institutional Animal Care and Use Committee approval, 10 athymic nude rats were divided into 2 groups. The experimental group (n = 6) underwent irradiation (20 Gy), while the control group (n = 4) underwent sham irradiation catheter placement only. All 10 rats underwent extraction of the second mandibular molar 7 days later. The rats were sacrificed 28 days after dental extraction, and their mandibles were harvested. The mandibles were examined with histologic analysis and bone volume analysis based on 3-dimensional micro–computed tomography.

Results

All 10 rats survived the experiment period. Radiographic and histologic analysis revealed decreased bone formation in the experimental group compared with the control group. Jaw region volume ratio was 0.83 for the experimental group versus 0.97 in the control group ( P = .003). The region-of-interest volume ratio was 0.75 in the experimental group and 0.97 in the control group ( P = .005). Histologically, there were increased osteoclasts ( P = .02) and decreased osteoblasts ( P = .001) as well as increased fibrosis in the experimental group versus the control group.

Conclusion

Mandibular osteoradionecrosis can be effectively and reproducibly produced in an athymic rat model. This will allow further research to study regenerative medicine in an athymic rat model.

Osteoclastic resorptive capacity is suppressed in patients receiving hyperbaric oxygen therapy

BACKGROUND AND PURPOSE

Hypoxia, necrosis, and bone loss are hallmarks of many skeletal diseases. Hyperbaric oxygen therapy (HBO) is often used as an adjunctive therapy in these cases. However the in vivo effect of HBO on osteoclast formation has not been fully established. We therefore carried out a longitudinal study to examine the effect of HBO on osteoclast formation and bone resorptive capacity in patients who were referred to the Plymouth Hyperbaric Medical Centre.

METHODS

Osteoclast precursors were isolated from peripheral blood prior to and following 10 and 25 daily hyperbaric treatments (100% O2 at 2.4 atmospheres absolute ATA for 90 min) to determine osteoclast formation and resorptive capacity. The expression of key regulators of osteoclast differentiation RANK, Dc-STAMP, and NFATc1 was also assessed by quantitative real-time PCR.

RESULTS

HBO reduced the ability of precursors to form osteoclasts and reduced bone resorption in a treatment-dependent manner. The initial suppressive effect of HBO was more pronounced on mononuclear osteoclast formation than on multinuclear osteoclast formation, and this was accompanied by reduction in the expression of key regulators of osteoclast formation, RANK and Dc-STAMP.

INTERPRETATION

This study shows for the first time that in vivo, HBO suppresses the ability of monocytic precursors to form resorptive osteoclasts.

Reconstruction of severely infected gluteal osteoradionecrosis using negative-pressure wound therapy and latissimus dorsi musculocutaneous flaps

Radiotherapy is mandatory for aggressive cancer treatment. Unfortunately, the high-energy radiation used can lead to severe osteoradionecrosis. Radical debridement of devitalized bone and soft tissue coupled with reconstruction using well-vascularized tissues is the accepted treatment for this condition. However, osteoradionecrosis cannot be controlled easily or rapidly. The aim of this study was to present the results of the use of serial negative-pressure wound therapy (NPWT) in combination with a latissimus dorsi myocutaneous flap for treatment of gluteal osteoradionecrosis in a consecutive series of patients. Between January 2003 and December 2012, nine patients underwent reconstruction using serial NPWT and latissimus dorsi myocutaneous flaps. We applied negative-pressure dressings for at least 8 weeks. Final reconstruction was performed after the infection was controlled. The superior gluteal artery and vein were used as recipient vessels in all the cases. The mean interval between operation and radiation therapy was 28.3 ± 8.3 years, and the mean number of debridement performed was 6.3 ± 1. NPWT dressings were applied for 8-12 weeks (mean, 9.3 ± 2 weeks). The defects ranged in size from 14 × 8 cm to 18 × 15 cm. The flap size ranged from 15 × 10 cm to 18 × 15 cm. All flaps survived uneventfully except in one patient who experienced chronic seroma and wound dehiscence. There were no recurrences of osteomyelitis during the follow-up periods (mean, 14 ± 6.1 months). Based on the results obtained from this consecutive series of patients, we suggest that this methodology may provide an alternative approach for the treatment of severe osteoradionecrosis of the gluteal region.

Osteoradionecrosis of the exenterated orbit

Osteoradionecrosis (ORN) occurs in an estimated 2% of head and neck-irradiated patients. It is seen most commonly in the mandible with other reported sites including the maxilla, temporal bone, clavicle, and vertebrae. It is defined as an area of exposed devitalised irradiated bone, with failure to heal during a period of at least 3 months, in the absence of local neoplastic disease. We report 2 cases of ORN following postoperative radiotherapy given to patients who had undergone an orbital exenteration. ORN can develop spontaneously in one-third of cases, although in the majority of patients, it is induced by secondary trauma. Radiotherapy induces an endarteritis in the small blood vessels of bone, thus favouring the generation of small thrombi that obliterate the vascular lumen and interrupt tissue perfusion. Likewise, irradiation impairs the function of osteoblasts, manifesting as osteopenia, with impairment of the repair and remodelling capacity of bone. Prior radiation exposure can thus decrease bone vascularity and injure its reserve reparative capacity. It is important to differentiate ORN from local recurrence of malignancy, bone metastasis, radiation-induced sarcoma, and infection. CT and MRI are effective diagnostic tools. Clinical management of ORN is complex and unsatisfactory. Treatment remains difficult, and prevention is paramount. A history of radiotherapy should alert clinicians to detect bone exposure or excessively prolonged socket healing. Early diagnosis with a high index of suspicion can achieve higher control rates with conservative management. Our case series reports a rare, previously unreported, but important complication of radiation therapy of the exenterated orbit.

Osteoradionecrosis of the mandible: a case series at a single institution

BACKGROUND

Osteoradionecrosis (ORN) defines exposed irradiated bone, which fails to heal over a period of 3-6 months without evidence of residual or recurrent tumor. In the previous decades, a staging and treatment protocol suggested by Marx, has dominated the approach to ORN. However, recently this paradigm is shifting. The purpose of this study was to evaluate our institutional experience in managing ORN through a retrospective review of case series from a large urban academic cancer centre.

METHODS

A retrospective chart review was conducted to include all ORN cases from 2003 to 2009 diagnosed at the Department of Otolaryngology - Head and Neck Surgery and the Department of Dentistry. The staging of ORN was assessed as affected by tumor site, tumor stage, radiotherapy modality and dose, chemotherapy, dental work, and time to diagnosis. The effectiveness of hyperbaric oxygen therapy (HBO) and surgery in the management of ORN was evaluated.

RESULTS

Fourteen cases of ORN were documented (incidence 0.84%). Primary subsites included tonsils, tongue, retromolar trigone, parotid gland, soft palate and buccal mucosa. There were 5 (35.7%) stage 1, 3 (21.4%) stage 2, and 6 (42.9%) stage 3 cases. ORN severity was not significantly associated with gender, smoking, alcohol use, tumor site, T stage, N stage, AJCC stage, or treatment modality (radiation alone, surgery with adjuvant radiation or adjuvant chemoradiation). Patients treated with intensity-modulated radiotherapy developed less severe ORN compared to those treated with conventional radiotherapy (p < 0.015). ORN stage did not correlate with radiation dose. In one patient only dental procedures were performed following radiation and could be implicated as the cause of ORN. HBO therapy failed to prevent ORN progression. Surgical treatment was required for most stage 2 (partial resections and free tissue transfers) and stage 3 patients (mandibulectomies and free tissue transfers, including two flaps in one patient). At an average follow up of 26 months, all patients were cancer-free, and there was no evidence of ORN in 84% of patients.

CONCLUSIONS

In early ORN, we advocate a conservative approach with local care, while reserving radical resections with robust reconstruction with vascularized free tissue for advanced stages.

A retrospective study of outcomes in subjects of head and neck cancer treated with hyperbaric oxygen therapy for radiation induced osteoradionecrosis of mandible at a tertiary care centre: an Indian experience

Osteoradionecrosis (ORN) of the mandible is a rare complication of radiation therapy for head and neck cancer. It manifests as an area of exposed necrotic bone failing to heal for at least 3 months. Our study aims to determine the effectiveness of HBO in management of radiation induced mandibular ORN. A retrospective study of 33 subjects of mandibular ORN treated with HBOT during period 2009-2011 was carried out. The mean patient age was 60 years (range 41-80).They were treated in a multiplace hyperbaric chamber at 2.4 ATA, for 90 min once a day for up to 30 sessions. Pre and post treatment improvement in relation to symptoms, healing of intraoral wound and overall wellbeing were evaluated. Out of 33 Subjects, 48 % (n = 16) cases showed complete healing of wound, 18 % (n = 6) had marked healing, slight healing in 24 % (n = 8) cases and 9 % (n = 3) cases had no change in healing. 70 % (23 of 33) cases had significant reduction in pain, 62 % (18 of 29) cases had improved jaw opening, 41 % (11 of 27) cases and 71 % (20 of 28) cases showed improvement in ability to talk and mouth dryness respectively. Overall 85 % (28 of 30) cases showed improvement. Our clinical experience supports the efficacy of HBO treatment for radiation induced mandibular ORN and we recommend additional multicentric, prospective studies to be carried out defining the role of HBOT using at least 30 sessions in such cases.

Surgical outcome and prognostic factors after treatment of osteoradionecrosis of the jaws

PURPOSE

This prospective study attempts to identify prognostic factors for outcome in patients Classes 2 and 3 osteoradionecrosis (ORN) treated using individualized methods.

METHODS

From 2005 to 2010, patients with Classes 2 and 3 osteoradionecrosis of the jaws were treated by the same surgical team using standard protocols. The patients were evaluated prospectively and followed up for a minimum of 12 months after completion of treatment. Two examinations were performed at least six months apart.

RESULTS

A total of 94 patients were assessed. Local debridement was performed in 33 patients (35.1 %), a rim resection with the application of a reconstruction plate was performed in 35 patients (37.2 %), and continuity resection in 26 patients (27.7 %). Postoperative wound infections locally or at the neck were detected in 69 patients (70.2 %), failure to eradicate radionecrosis occurred in 50 patients (53.2 %). The location of the primary tumor (p = 0.023) and radiation dose (p = 0.049), were associated with a significant risk of development of ORN. Prognostic factors for failure of treatment were the extent of initial osteoradionecrosis (p = 0.049) surgical treatment (p < 0.0001), number of debridements (p < 0.0001), type of microvascular free flap with (p < 0.0001), and grossly infected ORN (p < 0.0001).

CONCLUSIONS

Several factors affect the outcome of treatment of ORN. We confirm many of the intuitive factors influence outcome of treatment and add evidence that complete removal of affected bone and watertight well vascularized coverage is the most useful treatment strategy.

Etiology and treatment of osteonecrosis of the mandible

AIM OF THE STUDY

Post-radiogenic osteonecrosis of the mandible is a serious complication in patients with combined treated head/neck tumors. Osteonecrosis of the mandible can also occur following administration of bisphosphonates. In the present article we would like to present our experiences over the last five years in treating both bisphosphonate-associated osteonecrosis and osteoradionecrosis.

MATERIAL AND METHODS

Of the patients treated in our hospital for bone necrosis of the mandible between January 2005 and June 2010, 16 were diagnosed with infected osteoradionecrosis and 10 with bisphosphonate-associated osteonecrosis. The patients with osteoradionecrosis were administered the classic osteomyelitis treatment. The same procedure was carried out on 5 of the 10 patients with bisphosphonate-associated osteonecrosis; the remaining 5 were treated conservatively due to advanced bone infection. The bone biopsies and specimens of both entities yielded by the surgical interventions were examined histologically after decalcification.

RESULTS

Of the 16 patients treated for infected osteoradionecrosis, 7 recovered after decortication and long-term antibiosis. In 7 cases consolidation did not occur until after osseous continuity resection. In 2 cases the progress of the intraosseous infection could not be stopped with treatment. A typical first symptom of bisphosphonate-associated osteonecrosis was an alveolus that would not heal after a tooth extraction. In 50% of patients with bisphosphonate-associated osteonecrosis recovery was successful with a combination of surgery and long-term antibiosis. In the other patients with advanced bisphosphonate-associated osteonecrosis no definitive cure for the infection of the necrotic bone was possible.

CONCLUSION

In terms of treatment, osteoradionecrosis proves complex, yet easier to treat than bisphosphonate-associated osteonecrosis. The removal of the infected bone tissue is often necessary, but it does not always lead to recovery. Therefore it can be concluded that prevention of intraosseous infection by consistent pretherapeutic dental hygiene is especially important.