Osteoradionecrosis of the Jaws: Clinico-Therapeutic Management: A Literature Review and Update

Retrospective study of osteoradionecrosis in the jaws of patients with head and neck cancer

Objectives

Osteoradionecrosis (ORN) is one of the most severe complications resulting from radiotherapy (RT) in patients with head and neck cancer (HNC). It is characterized by persistent exposed and devitalized bone without proper healing for greater than 6 months after a high dose of radiation in the area. To describe the profile and dental management of ORN in HNC patients undergoing RT in an oncological clinical research center.

Materials and Methods

A retrospective descriptive study was performed to analyze dental records from HNC patients with ORN treated at an oncological clinical research center from 2013 to 2017. A total of 158 dental records for HNC patients were selected from a total of 583 records. Afterwards, this number was distributed to three examiners for manual assessments. Each examiner was responsible for selecting dental records that contained an ORN description, resulting in 20 dental records.

Results

Mean patient age was 60.3 years with males being the most affected sex (80.0%). The most affected area was the posterior region of the mandible (60.0%) followed by the anterior region of the mandible (20.0%) and the posterior region of the maxilla (10.0%). The factors most associated with ORN were dental conditions (70.0%) followed by isolated systemic factors (10.0%) and tumor resection (5.0%). There was total exposed bone closure in 50.0% of cases. The predominant treatment was curettage associated with chlorhexidine 0.12% irrigation (36.0%).

Conclusion

Poor dental conditions were related to ORN occurrence. ORN management through less invasive therapies was effective for the closure of exposed bone areas and avoidance of infection.

Osteoradionecrosis prevalence and associated factors: A ten years retrospective study

BACKGROUND

Osteoradionecrosis (ORN) is one of the most serious complications of head and neck radiotherapy and is considered a public health problem worldwide. This study aims to determine the prevalence and associated factors of ORN in patients undergoing radiotherapy for head and neck malignancy.

MATERIAL AND METHODS

A cross-sectional retrospective study was conducted, in which all medical records of patients undergoing head and neck radiation in the period between 2006 to 2015 (10 years) were examined. Clinical and demographic data were extracted. Multivariate Poisson regression analysis with robust variance was employed to access the relationship between ORN and independent variables (p < 0.05; 95% CI).

RESULTS

The sample comprised 413 medical records of patients undergoing radiotherapy. The prevalence of ORN was 9.7 %. Most participants were males (78.2%). The mean age of subjects was 55 years (± 14 years). The mandible was the main site of occurrence of ORN (85.0%). The following variables were associated with ORN : presence of oral mucositis (PR = 3.03; 95% CI: 1.30-7.03), history of smoking (PR = 0.23; 95% CI: 0.07-0.74), number of teeth removed before radiotherapy (PR = 1.06; 95% CI: 1.01-1.11) and visit to the dentist before radiation (PR = 0.08; 95% CI: 1.02-1.11).

CONCLUSIONS

The prevalence of ORN was low and was associated with the presence of oral mucositis and the number of removed teeth before radiation. Visiting the dentist before radiotherapy and stop-ping smoking were protective factors for ORN.

Current Understanding of the Pathophysiology of Osteonecrosis of the Jaw

PURPOSE OF REVIEW

Osteonecrosis of the jaw (ONJ) is a rare and severe necrotic bone disease reflecting a compromise in the body's osseous healing mechanisms and unique to the craniofacial region. Antiresorptive and antiangiogenic medications have been suggested to be associated with the occurrence of ONJ; yet, the pathophysiology of this disease has not been fully elucidated. This article raises the current theories underlying the pathophysiology of ONJ.

RECENT FINDINGS

The proposed mechanisms highlight the unique localization of ONJ. The evidence-based mechanisms of ONJ pathogenesis include disturbed bone remodeling, inflammation or infection, altered immunity, soft tissue toxicity, and angiogenesis inhibition. The role of dental infections and the oral microbiome is central to ONJ, and systemic conditions such as rheumatoid arthritis and diabetes mellitus contribute through their impact on immune resiliency. Current experimental studies on mechanisms of ONJ are summarized. The definitive pathophysiology is as yet unclear. Recent studies are beginning to clarify the relative importance of the proposed mechanisms. A better understanding of osteoimmunology and the relationship of angiogenesis to the development of ONJ is needed along with detailed studies of the impact of drug holidays on the clinical condition of ONJ.

Protective effects of α‑2‑macroglobulin on human bone marrow mesenchymal stem cells in radiation injury

Osteoradionecrosis of the jaws (ORNJ) is a complication of oral and maxillofacial malignancy that arises following radiotherapy; progressive jaw necrosis severely decreases the quality of life of patients. Human bone marrow mesenchymal stem cells (hBMMSCs) are a cell type with self‑renewal and pluripotent differentiation potential in the bone marrow stroma. These cells are associated with bone tissue regeneration and are one of the primary cell types affected by bone tissue radiation injury. α‑2‑macroglobulin (α2M) is a glycoprotein‑rich macromolecule that interacts with cytokines, growth factors and hormones to serve a variety of biological roles. In addition, α2M possesses radio‑protective effects. The aim of the present study was to investigate whether α2M has protective effects against radiation injury of hBMMSCs. Cell counting kit‑8 and colony formation assays were used to monitor cell proliferation. Western blot analysis and reverse transcription‑quantitative polymerase chain reaction were used to detect Beclin1, microtubule‑associated protein 1A/1B, sex determining region Y, Nanog, runt‑related transcription factor 2, osteoglycin and manganese superoxide dismutase expression. The formation of calcium nodules was evaluated by Alizarin red staining after osteogenic induction. Flow cytometric analysis of Annexin‑V and propidium iodide double staining was used to detect changes in apoptosis rate. Alkaline phosphatase and superoxide dismutase activity were determined using colorimetric assays. Reactive oxygen species levels were detected using 2',7'‑dichlorodihydrofluorescein diacetate. The results of the present study revealed that α2M increased the rate of proliferation, reduced autophagy, alleviated pluripotent differentiation injury, increased the osteogenic differentiation ability and decreased the rate of apoptosis in hBMMSCs following irradiation via an antioxidative pathway. In conclusion, α2M exhibited protective effects against radiation injury in hBMMSCs and may be considered a potential therapeutic agent for the prevention and treatment of ORNJ.

In-vivo imaging of the microvasculature of the soft tissue margins of osteonecrotic jaw lesions

Introduction Given the increasing incidence of medication-related jaw osteonecrosis, and recognition of the mucosal blood supply's importance, we have developed a non-invasive Real Time Optical Vascular Imaging (RTOVI) instrument. Imaging the red blood cells within the sub-mucosal capillary networks demonstrates the microcirculatory anatomy. We report a small trial, demonstrating the technique's viability, examining mucosal microcirculatory changes adjacent to osteonecrotic lesions.Aims Imaging the microvasculature of soft tissue margins of patients' exposed necrotic bone lesions in situ was intended to provide unique observational as well as quantitative data, using an image analysis routine, based on ImageJ software. Our interest was to evaluate whether this could offer valuable information for complex wound margin management.Methods Four osteoradionecrosis and four medication-related osteonecrosis patients (M:F 1:1 mean 68.25 years) were enrolled under the NRES Ethics 11/LON/0354 and KCL Research Ethics Committee (REC) BDM/14/15-14 approvals. Microvascular images from mucosal margins of exposed mandibular osteonecrosis lesions were compared with equivalent images from both uninvolved contralateral mucosa and similar mucosal sites in four healthy subjects.Results We demonstrated narrow hypo-vascularised oedematous lesion margins surrounded by a concentric inflammatory band and normal mucosa beyond. Parameters reporting individual capillary shape, via mean percentage of occupancy per capillary per field of view and capillary loop aspect ratio, differed significantly between groups (ANOVA, p = 0.0002 and p = 0.04 respectively). Values reporting capillary number and area showed expected changes but did not reach statistical significance.Conclusion This pilot study demonstrated the feasibility of mucosal microvascular imaging in assessing the microvascular changes found in the soft tissues at the margins of osteonecrotic lesions, with potential to inform therapeutic interventions and clinical decisions to continue or modify regime strategies at the earliest opportunity. Given the increasing incidence of medication-related jaw osteonecrosis, and the recognition of the importance of mucosal blood supply, we developed a non-invasive instrument demonstrating microcirculation anatomy by imaging transiting red blood cells.

Osteoradionecrosis of Jaw: An Institutional Experience

Aims and Objectives:

Osteoradionecrosis (ORN) of the jaw is a significant yet rare complication of radiotherapy (RT) associated with the management of head-and-neck malignancies. Recent decrease in the incidence of ORN following RT to the head and neck is being mainly attributed to refinement in RT techniques and improvement in our understanding of this morbid disease. The aim of this study is to assess the patients with ORN following head-and-neck RT to determine the various contributing risk factors involved in the development of ORN.

Subjects and Methods:

A retrospective data review from 2003 onward was conducted on the cases of ORN which presented to the Department of Dental and Oral Surgery, Christian Medical College, Vellore. Details of the patients with regard to the site of primary malignancy, type of treatment provided - RT alone or in combination of surgery and chemotherapy, dose of RT, presenting complaint, duration between the RT and presentation of ORN, and method of management considered were evaluated.

Results:

A total of 25 patients were evaluated. The average age of the 25 patients in our study was 58 years. Oropharynx (about 50%) was the leading site of primary malignancy. More than half of the patients in the study (52%) had undergone radical RT for the primary malignancy and all the patients were given >60 Gy dose of RT. About 48% of the patients in the study reported with pus discharge as their chief complaint. The average intervening time period from completion of RT to the presentation of ORN was 48 months. The mandibular alveolus was the most common site for ORN. Twelve of the 25 cases in the study were managed conservatively with only 3 patients requiring major resection.

Conclusion:

Due to its rare presentation, ORN still remains a challenge for the clinician in its management. Our study revealed that radical RT and concurrent chemo-RT for the oropharyngeal and base of the tongue malignancies have a higher risk of developing ORN. Patients subjected to the dose of RT above 60 Gy for head-and-neck malignancies have an increased risk of future ORN; henceforth, newer modality treatment like intensity-modulated RT regimen is recommended for such sites. Most of the patients in the study were satisfactorily managed of the symptoms with conservative modality treatment; hence, it is recommended to consider for surgical methods only in severe end-stage form of ORN.

Wound Healing Problems in the Mouth

Wound healing is a primary survival mechanism that is largely taken for granted. The literature includes relatively little information about disturbed wound healing, and there is no acceptable classification describing wound healing process in the oral region. Wound healing comprises a sequence of complex biological processes. All tissues follow an essentially identical pattern to complete the healing process with minimal scar formation. The oral cavity is a remarkable environment in which wound healing occurs in warm oral fluid containing millions of microorganisms. The present review provides a basic overview of the wound healing process and with a discussion of the local and general factors that play roles in achieving efficient would healing. Results of oral cavity wound healing can vary from a clinically healed wound without scar formation and with histologically normal connective tissue under epithelial cells to extreme forms of trismus caused by fibrosis. Many local and general factors affect oral wound healing, and an improved understanding of these factors will help to address issues that lead to poor oral wound healing.

Use of the Integra skin regeneration system in an intraoral mandibular defect in osteoradionecrosis

The objective was to trial the use of the Integra skin regeneration system intraorally to promote healing of an intraoral defect in osteoradionecrosis (ORN), thereby avoiding the necessity for mucosal flaps, free flaps, or skin grafts. A 54-year-old male patient presented with a pathological mandibular fracture at the angle, related to previous radiotherapy for tonsillar carcinoma, after the development of ORN. The fracture site was debrided and fixed with a reconstruction plate and the intraoral defect was dressed with the Integra two-layer system and an overlying pack. Three weeks later, the pack and silicone layer of the regeneration system were removed, showing early granulation over the previously exposed bone. At 8 weeks postoperative, the defect had healed completely with no need for further reconstruction. Using the method described, excellent healing was seen with the Integra skin regeneration system. A new use for the Integra skin regeneration system has been identified in the authors' unit. This method is minimally invasive and resulted in good healing in the case presented. The need for further reconstruction with associated increased patient morbidity was avoided in this case.