Osteoradionecrosis of the jaws--a current overview--part 1: Physiopathology and risk and predisposing factors

Endothelial progenitor cells improve the therapeutic effect of mesenchymal stem cell sheets on irradiated bone defect repair in a rat model

Background

The reconstruction of bone defects is often impaired by radiotherapy since bone quality is compromised by radiation. This study aims to investigate the therapeutic efficacy of the composite cell sheets-bone marrow mesenchymal stem cell (BMSC) sheets cocultured with endothelial progenitor cells (EPCs)-in the healing of irradiated bone defects and the biological effects of EPCs on the osteogenic properties of BMSC sheets.

Methods

BMSCs and EPCs were isolated from rat bone marrow. BMSCs were used to form cell sheets by the vitamin C inducing method. EPCs were seeded on BMSC sheets to make EPCs–BMSC sheets. Osteogenesis of EPCs–BMSC sheets and BMSC sheets were tested. In vitro osteogenesis tests included ALP, Alizarin Red S, Sirius Red staining, qRT-PCR and Western blot analysis after 3 and 7 days of osteogenic incubation. Subcutaneous osteogenesis was tested by H&E staining and immunohistochemical staining 8 weeks after transplantation. EPCs–BMSC sheets and BMSC sheets were used in the 3 mm defects of non-irradiated and irradiated rat tibias. Micro-CT and histological analysis were used to test the healing of bone defects 4 and 8 weeks after transplantation.

Results

EPCs–BMSC sheets showed enhanced osteogenic differentiation in vitro with increased expression of osteoblastic markers and osteogenesis related staining compared with BMSC sheets. In subcutaneous osteogenesis test, EPCs–BMSC sheets formed larger areas of new bone and blood vessels. The EPCs–BMSC group had the highest volume of newly formed bone in the defect area of irradiated tibias.

Conclusions

EPCs improved the osteogenic differentiation of BMSC Sheets and enhanced the ectopic bone formation. EPCs–BMSC sheets promoted bone healing in irradiated rat tibias. EPCs–BMSC sheets are potentially useful in the reconstruction of bone defect after radiotherapy.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1517-4) contains supplementary material, which is available to authorized users.

Imaging Evaluation of the Head and Neck Oncology Patient

Imaging plays a multifaceted role in the diagnosis and characterization of head and neck oncological patients and is integral to their care. Given the complexity of treatment, a multimodality approach is often necessary. With the advent of new technologies, imaging can also be used to predict tumor behavior and treatment response. In this chapter, with selected case examples, we describe the various imaging modalities available and offer suggestions on their utilization.

Immunoprecipitation high performance liquid chromatographic analysis of healing process in chronic suppurative osteomyelitis of the jaw

PURPOSE

Chronic suppurative osteomyelitis (CSO) of the jaw is one of the most difficult infectious diseases to manage, because it causes progressive bony destruction and is associated with bacterial inhabitation of the sequestra. A combination of antibiotic therapy and surgical debridement is often used to treat CSO. Nevertheless, various systemic conditions can lead to life-threatening complications.

METHODS

The present study aimed to explore the wound healing progress in 16 cases of CSO through protein expression analysis of postoperative exudates (POE) that were collected 6 h, 1 day, and 2 days after saucerization and/or decortication. A bony lesion was removed during surgery and then examined pathologically, and the CSO POE was examined by immunoprecipitation thus high performance chromatography (IP-HPLC). The POE at 6 h was used as a comparative control.

RESULTS

Histologically the CSO lesion showed a necrotic granulomatous lesion heavily infiltrated with polymorphonuclear leukocytes, macrophages, and plasma cells, admixed with multiple sequestra inhabited by bacterial colonies. The IP-HPLC analysis displayed a slight increase in innate immunity-related proteins, i.e., NFkB, TNFα, IL-1, IL-6, IL-28, and LL-37, but a gradual decrease of bacteria-related inflammatory proteins, i.e., IL-8, IL-12, CD31, CD68, and lysozyme. The angiogenesis-related proteins, i.e., VEGF-A and VEGF-C, were slightly decreased but TGF-β1 and bFGF were markedly increased on day 2. The osteogenesis-related proteins, i.e., OPG and ALP, were slightly increased, while the osteoclastogenesis-related protein, RANKL was slightly decreased compared to the control.

CONCLUSION

These findings indicate that the infected CSO undergoes a rapid wound healing process with active osteogenesis and a gradual decrease in bacteria-related inflammation, predicting a favorable prognosis after surgery. Moreover, IP-HPLC can be useful in monitoring the POE and wound healing processes during the postoperative period.

Late Temporal Lobe Extensive Osteoradionecrosis Post Radiation for Nasopharyngeal Carcinoma: Case Series

Osteoradionecrosis is one of the most serious complications of radiotherapy for nasopharyngeal carcinoma. We report three cases of osteoradionecrosis in temporal lobe who presented differently few years after completion of radiotherapy. Cranial magnetic resonance image showed lesions in temporal lobe either unilateral or bilateral with mass effect. One of the cases even showed disease progression few years after the initial diagnosis of osteoradionecrosis. Diagnosis of osteoradionecrosis for all three patients was confirmed by biopsy.

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.

Intensity-modulated proton therapy and osteoradionecrosis in oropharyngeal cancer

PURPOSE

We compared mandibular doses and osteoradionecrosis in patients with oropharyngeal cancer after intensity-modulated radiation therapy (IMRT) or intensity-modulated proton therapy (IMPT).

METHODS AND MATERIALS

We identified 584 patients who received definitive radiotherapy for oropharyngeal cancer from January 2011 through June 2014 at MD Anderson Cancer Center (534 IMRT and 50 IMPT). The dosimetric variables and osteoradionecrosis were compared with Chi-square test or Fisher's exact test.

RESULTS

Median follow-up time for all patients (534 IMRT and IMPT) was 33.8months (33.8months IMRT vs. 34.6months IMPT, P=0.854), and median time to osteoradionecrosis was 11.4months (range 6.74-16.1months). Mandibular doses were lower for patients treated with IMPT (minimum 0.8 vs. 7.3Gy; mean 25.6 vs. 41.2Gy; P<0.001), and osteoradionecrosis rates were lower as well: 2% IMPT (1 grade 1), 7.7% IMRT (12 grade 4, 5 grade 3, 1 grade 2 and 23 grade 1). Osteoradionecrosis location depended on the primary tumor site and high-dose field in the mandible.

CONCLUSIONS

Osteoradionecrosis events were significantly associated with higher dose irradiation to mandibular. Use of IMPT minimized excess irradiation of the mandible and consequently reduced the risk of osteoradionecrosis for oropharyngeal cancer.

The Use of Hyperbaric Oxygen for the Prevention and Management of Osteoradionecrosis of the Jaw: A Dana-Farber/Brigham and Women's Cancer Center Multidisciplinary Guideline

BACKGROUND

Osteoradionecrosis of the jaw (ORN) is an infrequent yet potentially devastating complication of radiation therapy to the head and neck region. Treatment options include antimicrobial therapy, local sequestrectomy, resection, and the use of hyperbaric oxygen (HBO). Published data on ORN are difficult to compare because of the lack of a universally accepted classification and staging system, and the literature on the use of HBO to either prevent or successfully manage ORN is controversial and inconclusive. Therefore, we aimed to establish a standard approach for using HBO at our institution.

MATERIALS AND METHODS

A literature search was conducted of articles published in the English language between January 1980 and January 2016. Retrieved articles were evaluated by two independent reviewers. Isolated case reports, abstracts, case series, review articles, and cohort studies without a control group were excluded; summary data were extracted from the remaining studies. A panel of experts from Head and Neck Oncology and Oral Medicine from the Dana-Farber Cancer Institute and Brigham and Women's Hospital reviewed the summary data and established multidisciplinary guidelines on the use of HBO for the prevention and management of ORN.

RESULTS

Seven studies were evaluated and reviewed by the multidisciplinary panel. There was no consistent evidence in support of HBO for either the prevention or management of ORN.

CONCLUSION

Based on the available evidence and expert opinion, routine use of HBO for the prevention or management of ORN is not recommended and is rarely used at our institution. The Oncologist 2017;22:343-350 IMPLICATIONS FOR PRACTICE: The Division of Head and Neck Oncology of Dana-Farber/Brigham and Women's Cancer Center does not recommend the routine use of HBO for the prevention or management of ORN. Adjunctive HBO may be considered for use on a case-by-case basis in patients considered to be at exceptionally high risk who have failed conservative therapy and subsequent surgical resection.

The Osteosarcoradionecrosis as an Unfavorable Result Following Head and Neck Tumor Ablation and Microsurgical Reconstruction

Osteoradionecrosis is preferably called osteosarcoradionecrosis to adequately cover the scope of the problem: multitissue necrosis. The changes following radiotherapy and leading to necrosis are further classified into 2 phases based on improved understanding of the underlying mechanisms. The reversible-damage phase could respond to the medical treatment, while the irreversible damage phase or osteosarcoradionecrosis may benefit from complete resection and free flap reconstruction. The role of ablation and reconstruction in paving the road for the development of osteosarcoradionecrosis is discussed, a case study provided, and a refined reconstructive approach proposed.

Potential risk factors for jaw osteoradionecrosis after radiotherapy for head and neck cancer

INTRODUCTION

To identify potential risk factors for the development of jaw osteoradionecrosis (ORN) after 3D-conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) among patients with newly diagnosed head and neck cancer.

MATERIAL AND METHODS

This study included 776 patients who underwent 3D-CRT or IMRT for head and neck cancer at the Department of Radiotherapy at the University Hospital Halle-Wittenberg between 2003 and 2013. Sex, dental status prior to radiotherapy, tumor site, bone surgery during tumor resection, concomitant chemotherapy, and the development of advanced ORN were documented for each patient. ORN was classified as grade 3, 4, or 5 according to the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer classification or grade 3 or 4 according to the late effects in normal tissues/subjective, objective, management, and analytic scale. The cumulative incidence of ORN was estimated. Cox regression analysis was used to identify prognostic risk factors for the development of ORN.

RESULTS

Fifty-one patients developed advanced ORN (relative frequency 6.6 %, cumulative incidence 12.4 %). The highest risk was found in patients who had undergone primary bone surgery during tumor resection (hazard ratio [HR] = 5.87; 95 % confidence interval [CI]: 3.09-11.19) and in patients with tumors located in the oral cavity (HR = 4.69; 95 % CI: 1.33-16.52). Sex, dentition (dentulous vs. edentulous), and chemotherapy had no clinically relevant influence.

DISCUSSION AND CONCLUSION

In contrast to most previous studies, we noted a low cumulative incidence of advanced ORN. Patients with tumors located in the oral cavity and those who undergo bone surgery during tumor resection prior to RT may be considered a high-risk group for the development of ORN.

Osteoradionecrosis and medication-related osteonecrosis of the jaw: similarities and differences

The purpose of this study was to compare medication-related osteonecrosis of the jaw (MRONJ) with osteoradionecrosis (ORN). Group 1 comprised 74 MRONJ patients (93 lesions) and group 2 comprised 59 ORN patients (69 lesions). Patient characteristics, clinical presentation of the lesions, the presence of complications, and the relationship with previous dental extractions were analyzed for both groups. Significant differences were found between the groups with regard to the characteristics of the patient populations, extraction as the precipitating event, the type of initial complaint, the prevalence of pain, and the location of the lesions. In the ORN group, significantly more patients complained of pain (P=0.0108) compared with the MRONJ group. Furthermore, significantly more pathological fractures (P<0.0001) and skin fistulae (P<0.0001) occurred in the ORN group. The treatment was more often conservative in the MRONJ group than in the ORN group (61.3% vs. 36.2%). Despite similarities in terms of imaging, risk factors, prevention, and treatment, MRONJ and ORN are two distinct pathological entities, as highlighted by the differences in patient characteristics, the initial clinical presentation, course of the disease, and outcome.

Comparison of the incidence of osteoradionecrosis with conventional radiotherapy and intensity-modulated radiotherapy

BACKGROUND

Modern techniques of radiotherapy are supposed to decrease the incidence of osteoradionecrosis of the mandible (ORNM). The purpose of this study was to compare the incidence of ORNM after intensity-modulated radiotherapy (IMRT) in comparison to conventional 3D conformal radiotherapy techniques (conventional RT).

METHODS

We conducted a retrospective study of consecutive unselected patients treated in a single institution between 2002 and 2012. To minimize confounding effects, only patients with oropharyngeal carcinoma without surgery of the primary site were included.

RESULTS

The cohorts included 145 patients in the conventional RT group and 89 patients in the IMRT group. Total incidence rate of ORNM was similar for both groups with rates of 11% versus 10% (n = 16 for conventional RT and n = 9 for IMRT; p = 1.0). Subanalysis revealed more ORNM in T4 classified lesions with IMRT (p = .007). Analysis of different risk factors showed no statistically significant difference between ORNM and no-ORNM patients.

CONCLUSION

We found no reduction in ORNM with IMRT. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1708-1716, 2016.

The role of myofibroblasts in the development of osteoradionecrosis in a newly established rabbit model

This study aimed to establish a proper animal model of osteoradionecrosis of jaws (ORNJ) and to observe preliminarily the characteristics of myofibroblasts, the key effector cell of fibrosis, in ORNJ. Rabbit mandibles were irradiated at three different doses based on a human equivalent radiation schedule, and examined by gross manifestation, single-photon emission computed tomography (SPECT), micro-computed tomography, sequential fluorochrome labeling, and histology. Immunohistochemistry staining of α-SMA was applied to detect the existence of myofibroblasts. The exposed necrotic bone, which is the main indication of ORNJ, started to be observed at all rabbits at 9 Gy. With the radiation dose increasing, the microarchitecture of the irradiated mandibles was more destroyed, the metabolism and mineralization of the irradiated mandibles diminished, the osteocytes number decreased, and more mature bones were substituted by fibrosis in the irradiated mandibles. In addition, as the radiation dose increased, the myofibroblast number increased and collected around the separated sequestrum, which indicated that myofibroblasts might relate to the pathogenesis of ORNJ. In summary, a clinically translational ORNJ model was successfully established in our study, and the role of myofibroblasts in the pathogenesis of ORNJ is described for the first time.

Low-level laser therapy/photobiomodulation in the management of side effects of chemoradiation therapy in head and neck cancer: part 2: proposed applications and treatment protocols

PURPOSE

There is a large body of evidence supporting the efficacy of low-level laser therapy (LLLT), more recently termed photobiomodulation (PBM) for the management of oral mucositis (OM) in patients undergoing radiotherapy for head and neck cancer (HNC). Recent advances in PBM technology, together with a better understanding of mechanisms involved and dosimetric parameters may lead to the management of a broader range of complications associated with HNC treatment. This could enhance patient adherence to cancer therapy, and improve quality of life and treatment outcomes. The mechanisms of action, dosimetric, and safety considerations for PBM have been reviewed in part 1. Part 2 discusses the head and neck treatment side effects for which PBM may prove to be effective. In addition, PBM parameters for each of these complications are suggested and future research directions are discussed.

METHODS

Narrative review and presentation of PBM parameters are based on current evidence and expert opinion.

RESULTS

PBM may have potential applications in the management of a broad range of side effects of (chemo)radiation therapy (CRT) in patients being treated for HNC. For OM management, optimal PBM parameters identified were as follows: wavelength, typically between 633 and 685 nm or 780-830 nm; energy density, laser or light-emitting diode (LED) output between 10 and 150 mW; dose, 2-3 J (J/cm(2)), and no more than 6 J/cm(2) on the tissue surface treated; treatment schedule, two to three times a week up to daily; emission type, pulsed (<100 Hz); and route of delivery, intraorally and/or transcutaneously. To facilitate further studies, we propose potentially effective PBM parameters for prophylactic and therapeutic use in supportive care for dermatitis, dysphagia, dry mouth, dysgeusia, trismus, necrosis, lymphedema, and voice/speech alterations.

CONCLUSION

PBM may have a role in supportive care for a broad range of complications associated with the treatment of HNC with CRT. The suggested PBM irradiation and dosimetric parameters, which are potentially effective for these complications, are intended to provide guidance for well-designed future studies. It is imperative that such studies include elucidating the effects of PBM on oncology treatment outcomes.

Mandibular changes on panoramic imaging after head and neck radiotherapy

OBJECTIVES

Changes to the radiographic appearance of the jaws after head and neck radiotherapy have not been thoroughly characterized. This retrospective study examines changes to the appearance of the mandible on panoramic images following intensity-modulated radiotherapy (IMRT) and relates these changes to medical co-morbidities and radiation dose.

STUDY DESIGN

The medical and dental charts, and panoramic images of 126 patients who received IMRT at the Princess Margaret Hospital between January 1, 2005, and December 31, 2008, were analyzed independently by three observers.

RESULTS

Of the 126 patients, 75 (60%) had post-IMRT changes, as seen on panoramic images; most, 66 (88%), consisted of widened periodontal ligament space (WPLS). The median time to WPLS was 29 months after IMRT. Female gender and radiation dose correlated with decreased time to WPLS.

CONCLUSIONS

These results indicate that WPLS is a common radiographic sequela after head and neck radiotherapy, underscoring its clinical significance as a reliable marker of irradiated bone. Furthermore, this type of WPLS needs to be differentiated from odontogenic inflammatory disease and cancer recurrence to avoid unnecessary treatment that may precipitate osteoradionecrosis.

[Osteoradionecrosis of the sternoclavicular joint]

BACKGROUND/OBJECTIVE

Osteoradionecrosis is a rare, but feared, late complication after radiotherapy of the head and neck region. Its localization to the sternoclavicular joint has rarely been described so far.

MATERIALS AND METHODS

Data are from a retrospective study that included all patients admitted to the authors' clinic with osteoradionecrosis of the sternoclavicular joint during the last 5 years. Therapy and outcome were evaluated and compared to the established literature.

RESULTS

Over the past 5 years, 2 patients have been treated for pronounced osteoradionecrosis of the sternoclavicular joint. Both patients had received postoperative radiotherapy for tumors of the neck and chest, and presented with lesions involving the clavicle and the sternum. After eliminating the suspicion of recurrent cancer, both radiologic imaging and histopathologic evaluation confirmed an infection. Aggressive debridement with partial claviculectomy, partial sternectomy, and reconstruction using a pectoralis flap lead to the patients' recovery.

CONCLUSION

Osteoradionecrosis does not only affect bone, but also the surrounding soft tissue. Due to the changes associated with previous radiotherapy, osteoradionecrosis should always be treated with radical debridement of the infected area, followed by flap reconstruction using unaffected tissue. The prognosis for the patient is then good.

Nonodontogenic mandibular lesions: differentiation based on CT attenuation

Mandibular lesions are classified as odontogenic and nonodontogenic based on the cell of origin. Odontogenic lesions are frequently encountered at head and neck imaging. However, several nonodontogenic pathologies may also involve mandible and present further diagnostic dilemma. Awareness of the imaging features of nonodontogenic lesions is crucial in order to guide clinicians in proper patient management. Computed tomography (CT) may provide key information to narrow diagnostic considerations. Nonodontogenic mandibular lesions may have lytic, sclerotic, ground-glass, or mixed lytic and sclerotic appearances on CT. In this article, our aim is to present various nonodontogenic lesions of the mandible by categorizing them according to their attenuations on CT.

Magnetic resonance imaging of the maxilla and mandible: signal characteristics and features in the differential diagnosis of common lesions

The maxilla and mandible are among the most difficult areas of the body to image with magnetic resonance techniques owing to the geometry of the jaws as well as the frequent susceptibility artifacts from dental restorations or appliances. This chapter briefly reviews the essentials of imaging techniques and basic anatomy and discusses the most common inflammatory conditions, benign and malignant lesions of the jaws, and temporomandibular joint. This review emphasizes and illustrates specific magnetic resonance features that facilitate characterization and diagnostic differentiation of these lesions. As the focus of this review is on the differentiation of infection and benign and malignant disease, a discussion of internal derangements and associated inflammatory disorders of the temporomandibular joint is beyond the scope of this review and is not discussed.

Hydrogen-rich saline may be an effective and specific novel treatment for osteoradionecrosis of the jaw

Hydrogen, a therapeutic medical gas, can exert antioxidant activity via selectively reducing cytotoxic reactive oxygen species such as hydroxyl radicals. Hydrogen-rich saline is an alternative form of molecular hydrogen that has been widely used in many studies, including metabolic syndrome, cerebral, hepatic, myocardial ischemia/reperfusion, and liver injuries with obstructive jaundice, with beneficial results. Osteoradionecrosis of the jaw is a serious complication following radiotherapy for head and neck cancers. It has long been known that most radiation-induced symptoms are caused by free radicals generated by radiolysis of H₂O, and the hydroxyl radical is the most reactive of these. Reducing the hydroxyl radical can distinctly improve the protection of cells from radiation damage. We hypothesized that hydrogen-rich saline might be an effective and specific method of managing and preventing osteoradionecrosis of the jaw.

Treatment of pathologic fracture following postoperative radiation therapy: clinical study

Background

Pathologic fractures are caused by diseases that lead to weakness of the bone structure. This process sometimes occurs owing to bony change after radiation therapy. Treatment of pathologic fractures may be difficult because of previous radiation therapy.

Methods

In this study, we analyzed clinical and radiographic data and progress of five patients with mandibular pathological fractures who had received postoperative radiation therapy following cancer surgery.

Result

Patients received an average radiation dose of 59.2 (SD, 7.2) Gy. Four of five patients exhibited bone union regardless of whether open reduction and internal fixation (OR/IF) was performed. Patients have the potential to heal after postoperative radiation therapy. Treatment of a pathologic fracture following postoperative radiation therapy, such as traditional treatment for other types of fractures, may be performed using OR/IF or CR. OR/IF may be selected in cases of significant bone deviation, small remaining bone volume, or occlusive change.

Conclusion

Patients have the potential to heal after postoperative radiation therapy.

Development of mandibular osteoradionecrosis in rats: Importance of dental extraction

OBJECTIVES

To develop an animal model of mandibular osteoradionecrosis (ORN) using a high-energy radiation source (as used in human therapeutics) and to assess the role of tooth extraction on ORN development.

MATERIALS AND METHODS (STUDY DESIGN)

Ten animals were irradiated with a single 35- or 50-Gy dose. Three weeks later, the second left mandibular molar was extracted from three animals in each group. Nine weeks after irradiation, the animals were euthanized, with an injection of contrast agent in the bloodstream to highlight vascularization. Mandibles were harvested and studied using micro-CT, histology, tartrate-resistant acid phosphatase activity and scanning electron microscopy.

RESULTS

This study demonstrates that a single 50-Gy dose associated with molar extraction is necessary for ORN development. In these conditions, absence of healing of the mucosa and bone, dental effects, fibrosis, an increase in osteoclast activity and a decrease in vascularization were observed. We also determined that molar extraction increases the impact of the cellular effects of radiation.

CONCLUSION

The mandibular ORN animal model was validated after 50-Gy irradiation and molar extraction. The results of this study therefore support an animal ORN model and tissue engineering strategies will now be developed to regenerate bone for patients with head and neck cancer.

Effect of Fluoride-Modified Titanium Surface on Early Adhesion of Irradiated Osteoblasts

Objective. The present study aimed to investigate the effect of fluoride-modified titanium surface on adhesion of irradiated osteoblasts. Materials and Methods. Fluoride-modified surface was obtained and the morphology, roughness, and chemical composition of the surface were evaluated by scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy, respectively. The adhesion of irradiated osteoblast-like cells, in terms of number, area, and fluorescence intensity on the titanium surface, was evaluated using immunofluorescence staining. Results. Numerous nanosize pits were seen only in the F-TiO surface. The pits were more remarkable and uniform on F-TiO surface than on TiO surface; however, the amplitude of peaks and bottoms on F-TiO surface appeared to be smaller than on TiO surface. The Sa value and Sdr percentage of TiO surfaces were significantly higher than those of F-TiO surface. The concentrations of main elements such as titanium, oxygen, and carbon were similar on both surfaces. The number of irradiated osteoblasts adhered on the control surface was larger than on fluoride-modified surface. Meanwhile, the cells on the fluoride-modified surface formed more actin filaments. Conclusions. The fluoride-modified titanium surface alters the adhesion of irradiated osteoblasts. Further studies are needed to investigate the proliferation, differentiation, maturation, gene expression, and cytokine production of irradiated osteoblasts on fluoride-modified titanium surface.

Dental implants in irradiated versus nonirradiated patients: A meta-analysis

The purpose of the present meta-analysis was to test the null hypothesis of no difference in dental implant failure rates, postoperative infection, and marginal bone loss for patients being rehabilitated by dental implants and being previously irradiated in the head and neck region versus nonirradiated patients against the alternative hypothesis of a difference. The study suggests that irradiation negatively affects the survival of implants, as well as the difference in implant location (maxilla vs mandible), but there is no statistically significant difference in survival when implants are inserted before or after 12 months after radiotherapy. The study failed to support the effectiveness of hyperbaric oxygen therapy in irradiated patients. It was observed that there was a tendency of lower survival rates of implants inserted in the patients submitted to higher irradiation doses. The results should be interpreted with caution because of the presence of uncontrolled confounding factors in the included studies.

Influence of genetic background and oxidative stress response on risk of mandibular osteoradionecrosis after radiotherapy of head and neck cancer

BACKGROUND

Osteoradionecrosis (ORN) of the mandible is a severe complication of head and neck radiotherapy (RT) treatment, where the impact of individual radiosensitivity has been a suggested explanation.

METHODS

A cohort of patients with stage II/III ORN was compared to matched controls. Blood was collected and irradiated in vitro to study the capacity to handle radiation-induced oxidative stress. Patients were also genotyped for 8 single-nucleotide polymorphisms (SNPs) in genes involved in the oxidative stress response.

RESULTS

A difference in 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) levels was found between the patient cohorts (p = 0.01). The SNP rs1695 in glutathione s-transferase p1 (GSTP1) was also found to be more frequent in the patients with ORN (p = .02). Multivariate analysis of the clinical and biological factors revealed concomitant brachytherapy plus the 2 biomarkers to be significant factors which influense risk of mandibular osteoradionecrosis after radiotherapy of head and neck cancer.

CONCLUSION

The current study indicates that oxidative stress response contributes to individual radiosensitivity and healthy tissue damage caused by RT and may be predicted by biomarker analysis.

Osteonecrosis of the Jaws in Dogs in Previously Irradiated Fields: 13 Cases (1989-2014)

The aim of this report was to characterize osteonecrosis of the jaws (ONJ) in previously irradiated fields in dogs that underwent radiotherapy (RT) for oral tumors. Osteoradionecrosis of the jaw (ORNJ) was further defined as osteonecrosis in a previously irradiated field in the absence of a tumor. Thirteen dogs clinically diagnosed with 15 ONJ lesions were included in this retrospective case series. Medical records were reviewed for: breed, sex, weight, and age of the patient, tumor type, location in the oral cavity and size, location of the ONJ, time from RT to ONJ onset, known duration of the ONJ, and tumor presence. Where available, histological assessment of tissues obtained from the primary tumor, and tissues obtained from the ONJ lesion, was performed, and computed tomographic (CT) images and dental radiographs were reviewed. RT and other treatment details were also reviewed. Twelve dogs developed ONJ in the area of the previously irradiated tumor or the jaw closest to the irradiated mucosal tumor. Recurrence of neoplasia was evident at the time of ONJ diagnosis in five dogs. Time from RT start to ONJ onset varied from 2 to 44 months. In three cases, ORNJ developed after dental extractions in the irradiated field. Dental radiographs mostly revealed a moth-eaten pattern of bone loss, CT mostly revealed osteolysis, and histopathology was consistent with osteonecrosis. To conclude, development of ONJ/ORNJ following RT is a rare, but potentially fatal complication. Patients undergoing RT may benefit from a comprehensive oral and dental examination and treatment prior to RT.

Osteoradionecrosis of the mandible: through a radiologist's eyes

Head and neck malignancies constitute a major cause of morbidity and mortality all over the world. Radiotherapy plays a pivotal role in the management of these tumours; however, it has associated complications, with mandibular osteoradionecrosis (ORN) being one of the gravest orofacial complications. Early diagnosis, extent evaluation, and detection of complications of ORN are imperative for instituting an appropriate management protocol. ORN can closely mimic tumour recurrence, the differentiation of which has obvious clinical implications. The purpose of the present review is to acquaint the radiologist with the imaging features of mandibular ORN and the ways to differentiate ORN from tumour recurrence.

Proposal for a new staging system for osteoradionecrosis of the mandible

A new staging system for osteoradionecrosis of the mandible has been retrospectively applied to a group of 31 patients. In this system clinicoradiographic signs and symptoms are incorporated in a simplified manner. For imaging purposes the use of plain radiographs such as periapical films and panoramic radiographs is recommended, mainly because of their readily availability. The presented staging system seems well reproducible, facilitating the comparison of study groups dealing with the various issues of osteoradionecrosis of the mandible. It is yet to be evaluated whether the presently proposed staging system is useful for management purposes.

Three-phase bone scintigraphy for imaging osteoradionecrosis of the jaw

This study evaluates the diagnostic utility of 3-phase bone scintigraphy for diagnosing osteoradionecrosis of the jaw (ORNJ).

METHODS

Thirty-two consecutive patients with a history of radiation to the head and neck region (range, 62-70 Gy; mean, 68 Gy; median, 69 Gy) due to squamous cell cancer and suspected ORNJ underwent 3-phase bone scans after injection of 520 to 750 MBq of Tc-MPD. In addition to planar scans, tomographic images (SPECT) were acquired in the second phase and SPECT/CT images during the third phase. Histopathologic findings (n = 18) and clinical follow-up (n = 14) served as reference standard for osteoradionecrosis.

RESULTS

The first, second, and third phases of planar images were rated positive in 18/32 patients (56.3%), 25/32 (78.1%), and 27/32 patients (84.4%), respectively. The late SPECT was positive in all patients (32/32, 100%), respectively. Histopathologic findings available in 18/32 patients (56.3%) confirmed ORNJ in all subjects. Acute inflammation was histologically proven in 18/18 specimens (100%) and additional chronic inflammation in 12/18 (66.7%). In 13/18 (72.2%) specimens, superinfection was evident histopathologically. A photopenic defect with surrounding hypermetabolism, a reported hallmark of ORJN, was found in less than 5%.

CONCLUSIONS

The predominant scintigraphic pattern of osteoradionecrosis includes increased bone mineralization phase in all patients. Central photopenia, reportedly a typical bone scan finding in bisphosphonate-induced osteonecrosis, was not characteristic for ORNJ. A differentiation of acute from chronic inflammatory processes was not possible.

Oral and dental late effects in survivors of childhood cancer: a Children's Oncology Group report

PURPOSE

Multi-modality therapy has resulted in improved survival for childhood malignancies. The Children's Oncology Group Long-Term Follow-Up Guidelines for Survivors of Childhood, Adolescent, and Young Adult Cancers provide practitioners with exposure- and risk-based recommendations for the surveillance and management of asymptomatic survivors who are at least 2 years from completion of therapy. This review outlines the pathophysiology and risks for oral and dental late effects in pediatric cancer survivors and the rationale for oral and dental screening recommended by the Children's Oncology Group.

METHODS

An English literature search for oral and dental complications of childhood cancer treatment was undertaken via MEDLINE and encompassed January 1975 to January 2013. Proposed guideline content based on the literature review was approved by a multi-disciplinary panel of survivorship experts and scored according to a modified version of the National Comprehensive Cancer Network "Categories of Consensus" system.

RESULTS

The Children's Oncology Group oral-dental panel selected 85 relevant citations. Childhood cancer therapy may impact tooth development, salivary function, craniofacial development, and temporomandibular joint function placing some childhood cancer survivors at an increased risk for poor oral and dental health. Additionally, head and neck radiation and hematopoietic stem cell transplantation increase the risk of subsequent malignant neoplasms in the oral cavity. Survivors require routine dental care to evaluate for potential side effects and initiate early treatment.

CONCLUSIONS

Certain childhood cancer survivors are at an increased risk for poor oral and dental health. Early identification of oral and dental morbidity and early interventions can optimize health and quality of life.

Mesenchymal stem cells systemically injected into femoral marrow of dogs home to mandibular defects to enhance new bone formation

Musculoskeletal diseases cost the U.S. $849 billion annually. To date, there has been no proof that remote long bone mesenchymal stem cells (BMSC) can home to craniofacial defects for bone regeneration. There has been no report that systemic BMSC injection can increase new bone formation in large animals. The objectives of this study were to use a sex-mismatched canine model for systemic BMSC injection and homing to mandibular defects and to investigate appendicular BMSC migration to craniofacial defects to increase new bone formation. Male beagle dog BMSC were injected into the femoral marrow cavity of female dogs upon which mandibular defects were created. The dogs were sacrificed at 6 weeks. Cells with Y chromosome markers were detected in defects of female dogs with systemic male BMSC injection, indicating the homing of the transplanted BMSC from femoral marrow to the mandibular defect. New bone formation in dogs with systemic BMSC injection was 20-40% higher than control without BMSC injection (p<0.05). Mineralized new bone percentage was increased by 20-40% due to systemic BMSC injection (p<0.05). In conclusion, this study proved that (1) allogeneic BMSC injected into long bone marrow are capable of homing to both appendicular and craniofacial bone in large animals and (2) systemically injected BMSC can significantly increase new bone formation in dog's mandibular defects. These results may help advance the understanding of stem cell homing and present a therapy to enhance bone repair, which may have a wide applicability to the regenerative medicine field.

Osteoradionecrosis of the mandible: a review

BACKGROUND

Osteoradionecrosis is a serious complication of radiotherapy that often leads to severe facial deformity, pain, pathological fracture, sequestration of devitalized bone, and orocutaneous fistulas. Preventive measures for osteoradionecrosis are the best treatment plan to avoid osteoradionecrosis. Radical surgery is indicated when conservative methods fail or when severe bone and soft-tissue necrosis prevails.

CASE REPORT

The purpose of this paper is to explore the recent theories about the definition, classification, incidence, and pathophysiology of osteoradionecrosis (ORN) of the jaws. The predisposing and risk factors for the development of osteoradionecrosis based on the literature review along with case report are also discussed.

DISCUSSION

A better understanding on the risk factors responsible for causing ORN and the underlying pathophysiology may improve our ability to prevent this complication and help to improve the prognosis for those being treated for osteoradionecrosis.

Posttreatment CT and MR imaging in head and neck cancer: what the radiologist needs to know

In patients with head and neck cancer, posttreatment imaging can be complicated and difficult to interpret because of the complexity of the surgical procedures performed and the postirradiation changes, but such imaging is critical for the evaluation of (a) the response to therapy and (b) tumor control. Posttreatment changes are affected by the type of surgery performed, reconstruction, neck dissection, and radiation therapy. Three types of flaps are used for reconstruction in the head and neck region: (a) the local flap, with geometric repositioning of adjacent tissue; (b) the pedicle flap, with rotation of donor tissue and preservation of the original vascular system; and (c) the free flap, with transfer of tissue that is revascularized by using microvascular surgical techniques. The posttreatment imaging findings in patients with head and neck cancer can be divided into four groups: altered anatomy secondary to surgical reconstruction, tumor recurrence, potential postsurgical complications, and possible postirradiation changes. Potential postsurgical complications are wound infection, abscess, fistula, flap necrosis, hematoma, chylous fistula, and serous retention. Possible postirradiation changes include mucosal necrosis, osteoradionecrosis, radiation-induced vasculopathy, radiation pneumonitis, radiation lung fibrosis, radiation-induced brain necrosis, and radiation-induced secondary malignancies. A familiarity with the imaging characteristics of posttreatment changes and of the potential complications caused by surgery and irradiation and an ability to differentiate these findings from tumor recurrence are essential for posttreatment surveillance and follow-up management of patients with head and neck cancer.

Raman spectroscopy demonstrates Amifostine induced preservation of bone mineralization patterns in the irradiated murine mandible

PURPOSE

Adjuvant radiotherapy in the management of head and neck cancer remains severely debilitating. Fortunately, newly developed agents aimed at decreasing radiation-induced damage have shown great promise. Amifostine (AMF) is a compound, which confers radio-protection to the exposed normal tissues, such as bone. Our intent is to utilize Raman spectroscopy to demonstrate how AMF preserves the mineral composition of the murine mandible following human equivalent radiation.

METHODS

Sprague Dawley rats were randomized into 3 experimental groups: control (n=5), XRT (n=5), and AMF-XRT (n=5). Both XRT and AMF groups underwent bioequivalent radiation of 70Gy in 5 fractions to the left hemimandible. AMF-XRT received Amifostine prior to radiation. Fifty-six days post-radiation, the hemimandibles were harvested, and Raman spectra were taken in the region of interest spanning 2mm behind the last molar. Bone mineral and matrix-specific Raman bands were analyzed using one-way ANOVA, with statistical significance at p<0.05.

RESULTS

The full-width at half-maximum of the primary phosphate band (FWHM) and the ratio of carbonate/phosphate intensities demonstrated significant differences between AMF-XRT versus XRT (p<0.01) and XRT versus control (p<0.01). There was no difference between AMF-XRT and control (p>0.05) in both Raman metrics. Computer-aided spectral subtraction further confirmed these results where AMF-XRT was spectrally similar to the control. Interestingly, the collagen cross-link ratio did not differ between XRT and AMF-XRT (p<0.01) but was significantly different from the control (p<0.01).

CONCLUSION

Our novel findings demonstrate that AMF prophylaxis maintains and protects bone mineral quality in the setting of radiation. Raman spectroscopy is an emerging and exceptionally attractive clinical translational technology to investigate and monitor both the destructive effects of radiation and the therapeutic remediation of AMF on the structural, physical and chemical qualities of bone.

Mesenchymal stem cells show radioresistance in vivo

Irradiation impacts on the viability and differentiation capacity of tissue-borne mesenchymal stem cells (MSC), which play a pivotal role in bone regeneration. As a consequence of radiotherapy, bones may develop osteoradionecrosis. When irradiating human bone-derived MSC in vitro with increasing doses, the cells’ self-renewal capabilities were greatly reduced. Mitotically stalled cells were still capable of differentiating into osteoblasts and pre-adipocytes. As a large animal model comparable to the clinical situation, pig mandibles were subjected to fractionized radiation of 2 χ 9 Gy within 1 week. This treatment mimics that of a standardized clinical treatment regimen of head and neck cancer patients irradiated 30 χ 2 Gy. In the pig model, fractures which had been irradiated, showed delayed osseous healing. When isolating MSC at different time points post-irradiation, no significant changes regarding proliferation capacity and osteogenic differentiation potential became apparent. Therefore, pig mandibles were irradiated with a single dose of either 9 or 18 Gy in vivo, and MSC were isolated immediately afterwards. No significant differences between the untreated and 9 Gy irradiated bone with respect to proliferation and osteogenic differentiation were unveiled. Yet, cells isolated from 18 Gy irradiated specimens exhibited a reduced osteogenic differentiation capacity, and during the first 2 weeks proliferation rates were greatly diminished. Thereafter, cells recovered and showed normal proliferation behaviour. These findings imply that MSC can effectively cope with irradiation up to high doses in vivo. This finding should thus be implemented in future therapeutic concepts to protect regenerating tissue from radiation consequences.

The convergence of radiation and immunogenic cell death signaling pathways

Ionizing radiation (IR) triggers programmed cell death in tumor cells through a variety of highly regulated processes. Radiation-induced tumor cell death has been studied extensively in vitro and is widely attributed to multiple distinct mechanisms, including apoptosis, necrosis, mitotic catastrophe (MC), autophagy, and senescence, which may occur concurrently. When considering tumor cell death in the context of an organism, an emerging body of evidence suggests there is a reciprocal relationship in which radiation stimulates the immune system, which in turn contributes to tumor cell kill. As a result, traditional measurements of radiation-induced tumor cell death, in vitro, fail to represent the extent of clinically observed responses, including reductions in loco-regional failure rates and improvements in metastases free and overall survival. Hence, understanding the immunological responses to the type of radiation-induced cell death is critical. In this review, the mechanisms of radiation-induced tumor cell death are described, with particular focus on immunogenic cell death (ICD). Strategies combining radiotherapy with specific chemotherapies or immunotherapies capable of inducing a repertoire of cancer specific immunogens might potentiate tumor control not only by enhancing cell kill but also through the induction of a successful anti-tumor vaccination that improves patient survival.

Myofibroblasts and their resistance to apoptosis: a possible mechanism of osteoradionecrosis

Osteoradionecrosis (ORN) in the head and neck area is the most devastating long-term complication of radiotherapy, with slow progression and inability to heal spontaneously. ORN can lead to intolerable pain, fractures, and sequestration of devitalized bone and fistulae, making oral feeding impossible and causing facial deformation. In spite of its notorious reputation over at least 90 years, the precise pathogenesis of ORN has not been fully clarified, which has led to obstacles in the management of the disease. Several theories about its pathogenesis have been formulated, and radiation-induced fibrosis is the newest one. According to this theory, ORN is essentially a type of fibrosis induced by radiotherapy, and antifibrosis therapy has been shown to be effective in its treatment. We assumed that ORN, like fibrosis in other organs, is the result of a process of fibrogenesis in which myofibroblasts are the key effector cells. The uninterrupted accumulation of myofibroblasts and consequent persistent excess production of collagenous extracellular matrix and tensile force result in loss of normal function and ultimately radiation-induced fibrosis. During this process, myofibroblasts may be protected from apoptosis by acquiring an immune-privileged capacity, which allows continuous matrix synthesis. If this hypothesis proves to be correct, it would enable better understanding of the cellular and molecular mechanisms underlying the pathogenesis and progression of ORN, and would help improve our ability to prevent occurrence of ORN, give an earlier diagnosis, and treat it more effectively.

Life-threatening cervical spine collapse as a result of postradiation osteonecrosis-case report and review of the literature

BACKGROUND

Mandibular osteoradionecrosis (ORN) is a well-known complication of head and neck radiotherapy; however, ORN of the cervical spine is rarely reported.

METHODS

Herein, we present a patient with a history of tonsillar carcinoma treated with chemoradiation who developed acute, severe progressive neck pain due to cervical spine collapse as a result of ORN. We also discuss diagnosis and treatment of cervical ORN based on a review of the literature.

RESULTS

The patient was successfully treated with antibiotics and surgical debridement and fixation.

CONCLUSION

Delayed diagnosis of cervical ORN can result in marked disability and pain due to spinal cord compression, as well as serious deformity and instability requiring surgical intervention, and even death. It is important for otolaryngologists who treat head and neck malignancies to be aware of this potential complication so that patients may be diagnosed as early as possible and treated with conservative measures.

[Radiation-related caries: etiology and possible preventive strategies. What should the radiotherapist know?]

BACKGROUND

After radiation treatment of head-and-neck cancer, the impairment of patient's quality of life still remains an issue. After completion of the treatment course, a substantial number of patients develop so-called radiation caries. In addition, almost 50% of all cases of infectious osteoradionecrosis (iORN) of the jaws are directly associated with radiation caries. This review addresses our current knowledge on the etiology and pathogenesis of radiation caries including possible preventive strategies.

MATERIALS AND METHODS

A PubMed search using the terms "radiation caries" ("radiation related caries", "radiation related damage to dentition") and "radiogenic caries" ("postradiation caries", "dental complications and radiotherapy") was performed. The analysis of its content focused on the etiology, the pathogenesis, and the available knowledge on prophylaxis as well as treatment of radiation caries.

RESULTS

For this review, 60 publications were selected. As main causal factors for radiogenic caries, either indirect impairment, resulting from alterations in the oral environment (e.g., radiation-induced xerostomia) or direct radiation-induced damage in teeth hard tissues are discussed. Radiation caries remains a lifelong threat and, therefore, requires permanent prevention programs.

CONCLUSION

To enable optimal medical care of the patients during the time course of radiotherapy as well as afterwards, close interdisciplinary cooperation between radiotherapists, oral surgeons, otorhinolaryngologists, and dentists is absolutely essential.

Feasibility of treating irradiated bone with intramedullary delivered autologous mesenchymal stem cells

Background. We aimed to explore (i) the short-term retention of intramedullary implanted mesenchymal stem cells BMSCs and (ii) their impact on the bone blood flow and metabolism in a rat model of hindlimb irradiation. Methods. Three months after 30 Gy irradiation, fourteen animals were referred into 2 groups: a sham-operated group (n = 6) and a treated group (n = 8) in which ¹¹¹In-labelled BMSCs (2 × 10⁶ cells) were injected in irradiated tibias. Bone blood flow and metabolism were assessed by serial ^99mTc-HDP scintigraphy and 1-wk cell retention by recordings of ^99mTc/¹¹¹In activities. Results. The amount of intramedullary implanted BMSCs was of 70% at 2 H, 40% at 48 H, and 38% at 168 H. Bone blood flow and bone metabolism were significantly increased during the first week after cell transplantation, but these effects were found to reduce at 2-mo followup. Conclusion. Short-term cell retention produced concomitant enhancement in irradiated bone blood flow and metabolism.