Osteoradionecrosis of the jaw: A mini review

Risk factors associated with the development of osteoradionecrosis (ORN) in Head and Neck cancer patients in Ireland: A 10-year retrospective review

BACKGROUND AND PURPOSES

To assess osteoradionecrosis (ORN) incidence in a population of Irish Head and Neck cancer (HNC) patients, and assess precipitating factors that may contribute to ORN development to aid prevention.

MATERIALS AND METHODS

Review of 1050 HNC patients attending the Dental Oncology Clinic, CUDSH between 2010 and 2021 identified 47 cases of ORN. Medical, dental and radiotherapy records of these forty-seven patients were retrospectively reviewed. Patient-, tumour-, and treatment-related variables were investigated in association with osteoradionecrosis development. Analysis conducted using SPSS, Pearson's Chi-square test (p < 0.05), and ordinal regression model.

RESULTS

ORN incidence was 4.4 %. Median time from radiotherapy (RT) to ORN development was 9.5 months (range 1-98.5 months). ORN development within the mandibular surgical site was significant (p <.001), presenting at a higher Notani grade (p =.002), in mid-mandibular body region (p =.028), at radiation doses ≥ 60 Gy (p =.035), due to induced causes (p =.029), and without resolution (p =.019).

CONCLUSION

This is the first retrospective study of ORN in HNC patients in Ireland over 10-year period. ORN incidence was extremely low (4.4%). As patients reported high smoking/alcohol use and poor dental attendance pre-diagnosis, this suggests intensive dental intervention pre/post-diagnosis contributed to low ORN rates. Mandibular surgery pre-RT increased risk of developing ORN at the surgical site. Therefore, we recommend future treatment planning should contour the surgical site, designating it an organ at risk (OAR), assigning a dose constraint, where oncologically possible, with emphasis on reducing the hot-spot to this region; findings reinforce importance of life-long expert dental care to reduce ORN incidence.

Proton FLASH Radiotherapy Ameliorates Radiation-induced Salivary Gland Dysfunction and Oral Mucositis and Increases Survival in a Mouse Model of Head and Neck Cancer

Head and neck cancer radiotherapy often damages salivary glands and oral mucosa, severely negatively impacting patients' quality of life. The ability of FLASH proton radiotherapy (F-PRT) to decrease normal tissue toxicity while maintaining tumor control compared with standard proton radiotherapy (S-PRT) has been previously demonstrated for several tissues. However, its potential in ameliorating radiation-induced salivary gland dysfunction and oral mucositis and controlling orthotopic head and neck tumor growth has not been reported. The head and neck area of C57BL/6 mice was irradiated with a single dose of radiotherapy (ranging from 14-18 Gy) or a fractionated dose of 8 Gy × 3 of F-PRT (128 Gy/second) or S-PRT (0.95 Gy/second). Following irradiation, the mice were studied for radiation-induced xerostomia by measuring their salivary flow. Oral mucositis was analyzed by histopathologic examination. To determine the ability of F-PRT to control orthotopic head and neck tumors, tongue tumors were generated in the mice and then irradiated with either F-PRT or S-PRT. Mice treated with either a single dose or fractionated dose of F-PRT showed significantly improved survival than those irradiated with S-PRT. F-PRT-treated mice showed improvement in their salivary flow. S-PRT-irradiated mice demonstrated increased fibrosis in their tongue epithelium. F-PRT significantly increased the overall survival of the mice with orthotopic tumors compared with the S-PRT-treated mice. The demonstration that F-PRT decreases radiation-induced normal tissue toxicity without compromising tumor control, suggests that this modality could be useful for the clinical management of patients with head and neck cancer.

Development and Standardization of an Osteoradionecrosis Classification System in Head and Neck Cancer: Implementation of a Risk-Based Model

PURPOSE

Osteoradionecrosis of the jaw (ORN) can manifest in varying severity. The aim of this study is to identify ORN risk factors and develop a novel classification to depict the severity of ORN.

METHODS

Consecutive patients with head and neck cancer (HNC) treated with curative-intent intensity-modulated radiation therapy (IMRT) (≥45 Gy) from 2011 to 2017 were included. Occurrence of ORN was identified from in-house prospective dental and clinical databases and charts. Multivariable logistic regression model was used to identify risk factors and stratify patients into high-risk and low-risk groups. A novel ORN classification system was developed to depict ORN severity by modifying existing systems and incorporating expert opinion. The performance of the novel system was compared with 15 existing systems for their ability to identify and predict serious ORN event (jaw fracture or requiring jaw resection).

RESULTS

ORN was identified in 219 of 2,732 (8%) consecutive patients with HNC. Factors associated with high risk of ORN were oral cavity or oropharyngeal primaries, received IMRT dose ≥60 Gy, current/ex-smokers, and/or stage III to IV periodontal condition. The ORN rate for high-risk versus low-risk patients was 12.7% versus 3.1% (P < .001) with an AUC of 0.71. Existing ORN systems overclassified serious ORN events and failed to recognize maxillary ORN. A novel ORN classification system, ClinRad, was proposed on the basis of vertical extent of bone necrosis and presence/absence of exposed bone/fistula. This system detected serious ORN events in 5.7% of patients and statistically outperformed existing systems.

CONCLUSION

We identified risk factors for ORN and proposed a novel ORN classification system on the basis of vertical extent of bone necrosis and presence/absence of exposed bone/fistula. It outperformed existing systems in depicting the seriousness of ORN and may facilitate clinical care and clinical trials.

Neurological complications of modern radiotherapy for head and neck cancer

Radiotherapy is one of the mainstay treatment modalities for the management of non-metastatic head and neck cancer (HNC). Notable improvements in treatment outcomes have been observed in the recent decades. Modern radiotherapy techniques, such as intensity-modulated radiotherapy and charged particle therapy, have significantly improved tumor target conformity and enabled better preservation of normal structures. However, because of the intricate anatomy of the head and neck region, multiple critical neurological structures such as the brain, brainstem, spinal cord, cranial nerves, nerve plexuses, autonomic pathways, brain vasculature, and neurosensory organs, are variably irradiated during treatment, particularly when tumor targets are in close proximity. Consequently, a diverse spectrum of late neurological sequelae may manifest in HNC survivors. These neurological complications commonly result in irreversible symptoms, impair patients' quality of life, and contribute to a substantial proportion of non-cancer deaths. Although the relationship between radiation dose and toxicity has not been fully elucidated for all complications, appropriate application of dosimetric constraints during radiotherapy planning may reduce their incidence. Vigilant surveillance during the course of survivorship also enables early detection and intervention. This article endeavors to provide a comprehensive review of the various neurological complications of modern radiotherapy for HNC, summarize the current incidence data, discuss methods to minimize their risks during radiotherapy planning, and highlight potential strategies for managing these debilitating toxicities.

Treatment Complications of Head and Neck Cancers and Rehabilitation Measures: A Narrative Review

Head and neck cancers (HNCs) are malignant tumors mainly from squamous cells in the head and neck tissues. Treatment involves a multidisciplinary approach with surgery, radiotherapy, and chemotherapy. However, the long-term prognosis for patients with advanced-stage tumors is guarded, with a median survival time of approximately 24 months. HNC patients have very high rates of depression and anxiety and the highest suicide rate among all cancers due to the intense and challenging nature of the treatment, underscoring the importance of our collective efforts. Rehabilitation success depends on various factors, including tumor, patient, and treatment-related factors. Patients may require post-treatment oral rehabilitation measures, including implants, obturators, and flexible dentures. These measures are crucial, but they often need to be more utilized. Patients may face challenges in maintaining oral hygiene and managing mucositis. Additionally, it is essential to address other intricacies such as trismus, xerostomia, gustatory dysfunctions, neuropathy, speech impairments, and psychological disturbances. Unfortunately, there is little literature on post-treatment rehabilitative measures. Despite its crucial role in improving patients' quality of life, rehabilitation often receives inadequate attention compared to treatment. Our narrative review, which covers various factors that affect rehabilitation, including oral rehabilitation measures and post-treatment complications, is anticipated to deliver practical insights to professionals and inspire positive changes in their regular practice.

Minimally Invasive Approach to Access Vessels for Microvascular Anastomosis in Head and Neck Reconstruction

OBJECTIVES

To describe our technique, review indications, and evaluate the outcomes of the minimal access approach for recipient vessel identification in microvascular tissue transfer.

METHODS

Retrospective chart review of all patients who underwent microvascular reconstruction using the minimal access technique between 2015 and 2021.

RESULTS

We report 236 cases, comprising 214 patients with a mean age of 60.2 years (3-88). The most common primary defect sites were the mandible (22.6%), cranium (14%), maxilla (13.2%), skull base (12.8%), and nose/nasal cavity (10.6%). Indications for free flap reconstruction included head and neck cancer extirpation (32.2%), osteoradionecrosis (29.7%), acquired deformity (14.0%), chronic wound (11.9%) and oral motor dysfunction (7.2%). Free flap donor sites used were the anterolateral thigh (84.3%), fibula (7.2%), and radial forearm (6.4%). Vessels utilized include superficial temporal (49.8%), facial (38.3%), angular (11.1%), and transverse cervical (0.4%). The overall complication rate was 14% (n = 33), with surgical complications at the recipient site accounting for 67.6% (n = 25). Flap failure occurred in 3.4% of procedures. Prior head and neck surgery and free flaps were associated with an increased risk of major recipient site complications (n = 20, p = 0.0257 and n = 14, p = 0.0117, respectively).

CONCLUSION

Minimal access techniques allow consistent recipient vessel identification for microvascular-free tissue transfer. These approaches may be utilized in reconstructing a broad range of head and neck defects, are low morbidity, and contribute to an overall shorter length of stay.

LEVEL OF EVIDENCE

2 Laryngoscope, 134:2177-2181, 2024.

Microstructural changes in the irradiated and osteoradionecrotic bone: a SEM study

Radiation exposure is a major health concern due to bone involvement including mandible, causing deleterious effects on bone metabolism, and healing with an increasing risk of infection and osteoradionecrosis. This study aims to investigate the radiotherapy-induced microstructural changes in the human mandible by scanning electron microscopy (SEM). Mandibular cortical bone biopsies were obtained from control, irradiated, and patients with osteoradionecrosis (ORN). Bone samples were prepared for light microscopy and SEM. The SEM images were analyzed for the number of osteons, number of Haversian canal (HC), diameter of osteon (D.O), the diameter of HC (D.HC), osteonal wall thickness (O.W.Th), number of osteocytes, and number of osteocytic dendrites. The number of osteons, D.O, D.HC, O.W.Th, the number of osteocytes, and osteocytic dendrites were significantly decreased in both irradiated and ORN compared to controls (p < .05). The number of HCs decreased in irradiated and ORN bone compared to the control group. However, this was statistically not significant. The deleterious effect of radiation continues gradually altering the bone quality, structure, cellularity, and vascularity in the long term (>5 years mean radiation biopsy interval). The underlying microscopic damage in bone increases its susceptibility and contributes further to radiation-induced bone changes or even ORN.

Case Report: Osteosclerotic metaphyseal dysplasia with optic nerve involvement and progressive osteonecrosis of the jaw due to a novel LRRK1 mutation

Background

Osteosclerotic metaphyseal dysplasia (OSMD, OMIM 615198) is an extremely rare autosomal recessive osteopetrosis disorder resulting in a distinctive pattern of osteosclerosis of the metaphyseal margins of long tubular bones. To date, only thirteen cases have been reported (eight molecularly confirmed). Five homozygous sequence variants in the leucine-rich repeat kinase 1 (LRRK1) gene have been identified to cause OSMD. We present two male siblings with OSMD with a novel LRRK1 variant.

Cases

The index case, now aged 6 years, was referred aged 9 months when diffuse sclerosis of the ribs and vertebral bodies, suggestive of osteopetrosis, was incidentally identified on a chest radiograph for suspected lower respiratory tract infection. Parents were consanguineous and of Pakistani origin. Further evaluation revealed developmental delay, nystagmus with bilateral optic nerve hypoplasia and severe visual impairment. Skeletal survey confirmed typical changes of OSMD, with widespread diffuse sclerosis and Erlenmeyer flask deformity of long bones. His older sibling, now aged 12 years, was 7 years at the time of referral and had similar clinical course and skeletal findings. Additionally, he had a chronic progressive osteonecrosis of the left mandible that required debridement, debulking and long-term antibiotics. Skeletal survey revealed findings similar to his sibling. Neither sibling had significant skeletal fractures or seizures. Unlike most previous reports suggesting sparing of the skull and lack of visual impairment, our patients had evidence of osteosclerosis of the cranium. Genetic screening for the common autosomal recessive and dominant pathogenic variants of osteopetrosis was negative. Whole Exome Sequencing (WES) followed by Sanger sequencing, identified a novel homozygous LRRK1 c.2506C>T p. (Gln836Ter) nonsense variant predicted to result in premature truncation of LRRK1 transcript.

Conclusion

Our cases confirm the autosomal recessive inheritance and expand the spectrum of genotype and phenotype of OSMD reported in the literature. Increasing reports of LRRK1 variants in this phenotype raise the question of whether LRRK1 should be included in targeted osteopetrosis panels. Bone histology in previous cases has shown this to be an osteoclast rich form of osteopetrosis raising the possibility that haematopoietic stem cell transplantation may be an appropriate treatment modality.

Development and Standardization of a Classification System for Osteoradionecrosis: Implementation of a Risk-Based Model

Purpose

Osteoradionecrosis of the jaw (ORN) can manifest in varying severity. The aim of this study is to identify ORN risk factors and develop a novel classification to depict the severity of ORN.

Methods

Consecutive head-and-neck cancer (HNC) patients treated with curative-intent IMRT (≥ 45Gy) in 2011-2018 were included. Occurrence of ORN was identified from in-house prospective dental and clinical databases and charts. Multivariable logistic regression model was used to identify risk factors and stratify patients into high-risk and low-risk groups. A novel ORN classification system was developed to depict ORN severity by modifying existing systems and incorporating expert opinion. The performance of the novel system was compared to fifteen existing systems for their ability to identify and predict serious ORN event (jaw fracture or requiring jaw resection).

Results

ORN was identified in 219 out of 2732 (8%) consecutive HNC patients. Factors associated with high-risk of ORN were: oral-cavity or oropharyngeal primaries, received IMRT dose ≥60Gy, current/ex-smokers, and/or stage III-IV periodontal disease. The ORN rate for high-risk vs low-risk patients was 12.7% vs 3.1% (p<0.001) with an area-under-the-receiver-operating-curve (AUC) of 0.71. Existing ORN systems overclassified serious ORN events and failed to recognize maxillary ORN. A novel ORN classification system, RadORN, was proposed based on vertical extent of bone necrosis and presence/absence of exposed bone/fistula. This system detected serious ORN events in 5.7% of patients and statistically outperformed existing systems.

Conclusion

We identified risk factors for ORN, and proposed a novel ORN classification system based on vertical extent of bone necrosis and presence/absence of exposed bone/fistula. It outperformed existing systems in depicting the seriousness of ORN, and may facilitate clinical care and clinical trials.

Valero's host index is useful in predicting radiation-induced trismus and osteoradionecrosis of the jaw risks in locally advanced nasopharyngeal carcinoma patients

BACKGROUND

In the absence of previous research, we sought to assess the H-Index's predictive significance for radiation-induced trismus (RIT) and osteoradionecrosis of the jaw (ORNJ) in patients with locally advanced nasopharyngeal carcinoma (LA-NPC) receiving concurrent chemoradiotherapy (C-CRT).

PATIENTS AND METHODS

The research comprised 295 LA-NPC patients who had C-CRT and pre- and post-C-CRT oral exams between June 2010 and December 2021. The H-Index was calculated using neutrophils, monocytes, lymphocytes, hemoglobin, and albumin measurements obtained on the first day of C-CRT. Patients were divided into three and two H-index groups, respectively, based on previously established cutoff values (1.5 and 3.5) and the cutoff value determined by our receiver operating characteristic (ROC) curve analysis. The primary objective was the presence of any significant connections between pretreatment H-Index groups and post-C-CRT RIT and ORNJ rates.

RESULTS

RIT and ORNJ was diagnosed in 46 (15.6%) and 13 (7.8%) patients, respectively. The original H-Index grouping could only categorize RIT and ORNJ risks at a cutoff value of 3.5, with no significant differences in RIT and ORNJ rates between groups with H-Index 1.5 and 1.5 to 3.5 (P < 0.05 for each). The ideal H-Index cutoff for both RIT and ORNJ rates was found to be 5.5 in ROC curve analysis, which divided the entire research population into two groups: H-Index ≤ 5.5 (N = 195) and H-Index > 5.5 (N = 110). Intergroup comparisons revealed that patients in the H-Index > 5.5 group had significantly higher rates of either RIT (31.8% vs. 5.9%; P < 0.001) or ORNJ (17.3% vs. 2.2%; P < 0.001) than their H-Index ≤ 5.5 counterparts. The results of the multivariate analysis showed that H-Index > 5.5 was independently linked to significantly higher RIT (P < 0.001) and ORNJ (P < 0.001) rates.

CONCLUSION

Pre-C-CRT H-Index > 5.5 is associated with significantly increased RIT and ORNJ rates in LA-NPC patients receiving definitive C-CRT.

Osseous Tissue Engineering in the Management of Mandibular Osteoradionecrosis - An Evaluative Study

Introduction

Osteoradionecrosis (ORN), a non-infectious, necrotic condition of the bone, occurs as a major complication of radiotherapy to the irradiated site. Simple irrigation of the involved bone to partial or complete resection of the involved bones is being employed in its conventional management. Osseous tissue engineering (OTE) provides a new strategy by regenerating bone cells along with biocompatible scaffolds and micromolecules to produce an engineered osseous tissue.

Materials and Methods

In this study, mandibular ORN following radiation secondary to oropharyngeal squamous cell carcinoma was included. OTE with composite engineered tissue containing a mixture of autologous culture expanded dental pulp stem cells (DPSCs), autologous uncultured bone marrow aspiration concentrate (BMAC) and autologous platelet-rich plasma (PRP) loaded in β-tricalcium phosphate (β-TCP) or hydroxyapatite (HA) sponge scaffold was used in the mandibular defect and the surrounding tissues. An assessment of clinical, radiological and functional attributes was done.

Results

A total of six cases with a mean age of 58.6 years were included in the study. We noted significant improvement in the mean post-operative score for pain and mouth opening; functional improvement in eating solid/liquid food, tongue movement, speech and deglutition were observed. The aesthetics was measured with Vancouver score and revealed a significance at P < 0.05; also lip competency and occlusion were noted in all the patients. No major complications were noticed until a mean follow-up of 28 months.

Discussion

Tissue engineering with a regenerative cocktail of autologous culture expanded DPSCs, autologous uncultured BMAC and autologous PRP loaded in HA or β-TCP utilised in the surgical reconstruction of the mandible is an effective treatment modality in the management of mandibular ORN following irradiation.