Adjunctive hyperbaric oxygen in irradiated patients requiring dental extractions: outcomes and complications

Efficacy of adjunctive modalities during tooth extraction for the prevention of osteoradionecrosis: A systematic review and meta-analysis

BACKGROUND

Jaw osteoradionecrosis (ORN) is a complication in patients with previous head and neck radiotherapy. Its incidence increases with dental extractions. Hence, this review aimed to evaluate the efficacy of adjunctive treatment modalities undertaken at the time of extraction in previous head and neck radiotherapy patients in preventing ORN.

METHODS

A systematic review was conducted, where studies with data on ORN incidence after extraction with or without adjunctive interventions were included. Meta-analyses were conducted to estimate the pooled prevalence of ORN per intervention and the pooled odds ratio for incidence of ORN between interventions.

RESULTS

In total, 1520 patients in 29 studies were included. Interventions identified were hyperbaric oxygen (HBO), pentoxifylline-tocopherol (PENTO), antibiotics (ABX), platelet-rich fibrin and photobiomodulation. The pooled prevalence of ORN for HBO (4.6%), PENTO (3.4%) and ABX (3.8%) was significantly lower than the Control (17.6%). For studies with direct comparisons between groups, HBO had lower but not significant odds of developing ORN than the Control (OR 0.27) and ABX (OR 0.57).

CONCLUSIONS

HBO, PENTO and ABX may reduce the incidence of ORN compared to no intervention. Given that all three have similar incidences of ORN, ABX may be the most cost-effective and accessible adjunctive modality.

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.

Predictors of osteoradionecrosis following irradiated tooth extraction

Background

Tooth extraction post radiotherapy is one of the most important risk factors of osteoradionecrosis of the jawbones. The objective of this study was to determine the predictors of osteoradionecrosis (ORN) which were associated with a dental extraction post radiotherapy.

Methods

A retrospective analysis of medical records and dental panoramic tomogram (DPT) of patients with a history of head and neck radiotherapy who underwent dental extraction between August 2005 to October 2019 was conducted.

Results

Seventy-three patients fulfilled the inclusion criteria. 16 (21.9%) had ORN post dental extraction and 389 teeth were extracted. 33 sockets (8.5%) developed ORN. Univariate analyses showed significant associations with ORN for the following factors: tooth type, tooth pathology, surgical procedure, primary closure, target volume, total dose, timing of extraction post radiotherapy, bony changes at extraction site and visibility of lower and upper cortical line of mandibular canal. Using multivariate analysis, the odds of developing an ORN from a surgical procedure was 6.50 (CI 1.37–30.91, p = 0.02). Dental extraction of more than 5 years after radiotherapy and invisible upper cortical line of mandibular canal on the DPT have the odds of 0.06 (CI 0.01–0.25, p < 0.001) and 9.47 (CI 1.61–55.88, p = 0.01), respectively.

Conclusion

Extraction more than 5 years after radiotherapy, surgical removal procedure and invisible upper cortical line of mandibular canal on the DPT were the predictors of ORN.

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.

Hyperbaric oxygen treatment for the management of radiation-induced xerostomia

INTRODUCTION

Hyperbaric oxygen therapy (HBOT) is widely used for the treatment of the late effects of radiation therapy. We report a prospective observational cohort study of 51 patients designed to examine the effectiveness of hyperbaric oxygen treatment (HBOT) for xerostomia following radiotherapy.

METHODS

Objective (saliva volume) and subjective (quality of life scoring and visual analogue scale (VAS) of discomfort) measurements associated with xerostomia were compared prior to commencement of HBOT, after 30 sessions (over 6 weeks) of HBOT at 243 kPa for 90 minutes daily for five days per week and at 6-week review (12 weeks from commencement).

RESULTS

One hundred and one courses of treatment in 99 patients were examined. For 53 (53%) courses in 51 patients, data were recorded before and after HBOT and so could be included in the analysis. Thirty-four (34%) of these patients had complete data for all three time points. The unit of study was per treatment course, not per person. There were no major complications to HBOT. There was a statistically significant difference in saliva volume following HBOT (P = 0.016). The mean saliva volume increase was 0.9 mL over a 5-min collection period (95% CI 0.2-1.5). There was also a statistically significant improvement in discomfort after HBOT (P < 0.001) and QOL (P < 0.001). The mean visual analogue scale for discomfort (VAS on a 0-10 scale) score decreased by 1.4 units (95% CI 0.7-2.1), whilst the mean QOL score was 10 points lower after treatment (95% CI 5.9-14.4).

CONCLUSION

Hyperbaric oxygen therapy may be a safe and effective treatment for symptoms of xerostomia after radiation therapy and should be considered when available.

The role of hyperbaric oxygen therapy in the prevention and management of radiation-induced complications of the head and neck - a systematic review of literature

Radiation therapy for the treatment of head and neck cancer can injure normal tissues and have devastating side effects. Hyperbaric oxygen (HBO) is known to reduce the severity of radiation-induced injury by promoting wound healing. While most of the research in literature has focused on its efficacy in osteonecrosis, HBO has other proven benefits as well. The aim of this review was to identify the various benefits of hyperbaric oxygen therapy in patients who have undergone radiation for head and neck cancer. An electronic database search was carried out to identify relevant articles and selected articles were reviewed in detail. The quality of evidence for each benefit, including preserving salivary gland function, preventing osteonecrosis, dental implant success, and overall quality of life, was evaluated. Evidence showed that HBO was effective in improving subjective symptoms of xerostomia, swallowing, speech and overall quality of life. There was no conclusive evidence to show that HBO improved implant survival, prevented osteonecrosis, or improved salivary gland function. The high costs and accessibility of HBO therapy must be weighed against the potential benefits to each patient.

Fibular flap for mandible reconstruction in osteoradionecrosis of the jaw: selection criteria of fibula flap

BACKGROUND

Osteoradionecrosis is the most dreadful complication after head and neck irradiation. Orocutaneous fistula makes patients difficult to eat food. Fibular free flap is the choice of the flap for mandibular reconstruction. Osteocutaneous flap can reconstruct both hard and soft tissues simultaneously. This study was to investigate the success rate and results of the free fibular flap for osteoradionecrosis of the mandible and which side of the flap should be harvested for better reconstruction.

METHODS

A total of eight consecutive patients who underwent fibula reconstruction due to jaw necrosis from March 2008 to December 2015 were included in this study. Patients were classified according to stages, primary sites, radiation dose, survival, and quality of life.

RESULTS

Five male and three female patients underwent operation. The mean age of the patients was 60.1 years old. Two male patients died of recurred disease of oral squamous cell carcinoma. The mean dose of radiation was 70.5 Gy. All fibular free flaps were survived. Five patients could eat normal diet after operation; however, three patients could eat only soft diet due to loss of teeth. Five patients reported no change of speech after operation, two reported worse speech ability, and one patient reported improved speech after operation. The ipsilateral side of the fibular flap was used when intraoral soft tissue defect with proximal side of the vascular pedicle is required. The contralateral side of the fibular flap was used when extraoral skin defect with proximal side of the vascular pedicle is required.

CONCLUSIONS

Osteonecrosis of the jaw is hard to treat because of poor healing process and lack of vascularity. Free fibular flap is the choice of the surgery for jaw bone reconstruction and soft tissue fistula repair. The design and selection of the right or left fibular is dependent on the available vascular pedicle and soft tissue defect sites.

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.

Systematic review of hyperbaric oxygen therapy for the treatment of non-neurological soft tissue radiation-related injuries

PURPOSE

The purpose of this paper was to provide an evidence-based evaluation of the safety and effectiveness of hyperbaric oxygen therapy (HBOT) for the treatment of non-neurological soft tissue radiation-related injuries (STRI).

METHODS

Systematic searches of medical bibliographic databases, the Internet, and lists of references were conducted in December 2010 and April 2013 to identify relevant primary studies. Inclusion and classification of papers was resolved through the application of a predetermined protocol. Information on both the safety and effectiveness of HBOT was analyzed.

RESULTS

Forty-one articles were included, with 11 comparing HBOT to a regimen without HBOT. Comparative evidence varied considerably in methodological quality, and numerous limitations were identified. Absolute data showed that serious adverse events after HBOT were rare, while more common adverse events were minor and self-limiting. Compared to observation, conventional, or sham therapies, evidence of benefit in clinical outcomes was shown for HBOT for radiation proctitis and wounds in irradiated soft tissue of the head and neck, but not for postirradiation soft tissue edema or radiation cystitis. Clinical outcomes differed little between HBOT and argon plasma coagulation for radiation proctitis and between HBOT and hyaluronic acid for radiation cystitis.

CONCLUSIONS

HBOT is a safe intervention which may offer clinical benefits to patients suffering from radiation proctitis and non-neurological STRI of the head and neck. However, differing clinical responses across STRI demonstrate a need for further well-designed clinical trials to validate the use of HBOT for individual STRI, both as an adjunct to conventional treatments and relative to definitive treatments.

The use of computer-aided manufacturing during the treatment of the edentulous mandible in an oral radiation therapy patient: clinical report

This clinical report describes the treatment of an edentulous patient with previous radiation therapy to the base of the tongue. A computer-aided manufactured titanium framework was used to fabricate the implant-supported fixed complete denture and meet the functional and psychosocial needs of the patient.

Ionising irradiation-induced inhibition of differentiation of C3H10T1/2 cells to the osteoblastic lineage

PURPOSE

Previous studies using mouse osteoblast derived MC3T3-E1 and mouse myoblast derived C2C12 cells have not completely explained the mechanisms responsible for osteoradionecrosis. Thus, the aim of this study was to advance the in vitro experimental approaches for investigations of osteoradionecrosis.

MATERIALS AND METHODS

The pluripotent stem cell line, mouse embryo derived C3H10T1/2, was treated with all-trans-retinoic acid after irradiation (1, 3 and 6 Gy), and cell growth, cell cycle distribution, apoptosis, and alkaline phosphatase (ALP) activity were assessed.

RESULTS

We demonstrated that ionising radiation inhibited the growth and decreased ALP activity in C3H10T1/2 cells. The decrease in cell growth was not due to apoptosis but was due to cell cycle delay. The decrease in ALP activity persisted in cells that were induced to an osteoblastic lineage 24 h after irradiation.

CONCLUSIONS

Our results suggested that C3H10T1/2 cells are suitable for investigating the effects of ionising irradiation on osteoblast precursor cells.

Efficacy of pre- and postirradiation hyperbaric oxygen therapy in the prevention of postextraction osteoradionecrosis: a systematic review

PURPOSE

There is still considerable controversy regarding whether hyperbaric oxygen (HBO) therapy used preoperatively and postoperatively will prevent osteoradionecrosis in previously irradiated patients undergoing tooth extraction. The purpose of this systematic review was to evaluate the best evidence available in an attempt to find an answer to this question.

MATERIALS AND METHODS

The literature search on Medline covered the period from January 1948 to March 2008. Included were randomized clinical trials, prospective studies without randomization, case-control studies, retrospective studies, and observational studies with and without control groups. This search retrieved 696 citations, which was reduced to 14 acceptable publications based on an assessment of methodologic quality. They included 1 randomized clinical trial, 8 cohort-controlled studies, and 5 observational studies. These were analyzed for radiation dose, type of radiation, use of adjunctive cancer treatments, number and location of extractions, method of extraction, HBO protocol, and use of adjunctive therapy besides HBO.

RESULTS

Most of the studies had a small sample size, lacked specific inclusion and exclusion criteria, did not report the interval between radiation and extraction, and provided limited information on the method of extraction. There was also variation in HBO protocols, radiation dosage, the use of antibiotics, and the use of adjunctive cancer therapy.

CONCLUSION

On the basis of the best available evidence, there is currently insufficient information to show that the use of HBO reduces the incidence of osteoradionecrosis in irradiated patients requiring tooth extraction.

Osteoradionecrosis of the jaws--a current overview--Part 2: dental management and therapeutic options for treatment

PURPOSE

The aim of this paper is to explore the current theories about pretreatment assessment and dental management of patients receiving head and neck radiotherapy, and the therapeutic options to treat osteoradionecrosis of the jaws, based on the literature review.

DISCUSSION

Osteoradionecrosis is one of the most serious oral complications of head and neck cancer treatment. Osteoradionecrosis is a severe delayed radiation-induced injury, characterized by bone tissue necrosis and failure to heal. Osteoradionecrosis either stabilizes or gradually worsens and is notoriously difficult to manage. Because most cases occur in patients who were dentulous in the mandible at tumor onset, proper dental management is the single most important factor in prevention.

CONCLUSIONS

Complete dental clearance before treatment is no longer necessary. Controversy exists regarding the management of osteoradionecrosis of the maxillofacial skeleton because of the variability of this condition. The treatment of osteoradionecrosis has included local wound care, antibiotic therapy, surgical procedures, and the administration of hyperbaric oxygenation. Recently, new methods of treatment were introduced, according to the new theory about its pathophysiology.

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

PURPOSE

The aim of this paper is to explore the current theories about definition, classification, incidence and physiopathology of osteoradionecrosis (ORN) of the jaws. Moreover, it is discussed the predisposing and risk factors for the development of osteoradionecrosis based on the literature review.

DISCUSSION

Osteoradionecrosis is one of the most serious oral complications of head and neck cancer treatment. Osteoradionecrosis is a severe delayed radiation-induced injury, characterised by bone tissue necrosis and failure to heal. Osteoradionecrosis either stabilises or gradually worsens and is notoriously difficult to manage. The most widely accepted theory to explain its cause until recently was the theory of hypoxia, hypovascularity and hypocellularity. A new theory for the pathogenesis of osteoradionecrosis was proposed. The clinical presentations of osteoradionecrosis are pain, drainage and fistulation of the mucosa or skin that is related to exposed bone in an area that has been irradiated. The tumour size and location, radiation dose, local trauma, dental extractions, infection, immune defects and malnutrition can predispose its development.

CONCLUSIONS

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

Dental extractions and radiotherapy in head and neck oncology: review of the literature

Management of irradiated patients with cancer in the head and neck region represents a challenge for multidisciplinary teams. Radiotherapy promotes cellular and vascular decrease that results in a low response rate in the healing. Consequently, surgical procedures in irradiated tissues present high rates of complication. Osteoradionecrosis (ORN) is the most severe sequelae caused by radiotherapy. It is associated with previous extractions especially those carried out post-irradiation. The management of this side effect is difficult and can result in bone or soft tissue loss, affecting the quality of life. The literature regarding dental extractions performed before and after head and neck radiotherapy was evaluated, focusing on indications, criteria, surgical techniques and adjunctive therapies such as antibiotics and hyperbaric oxygen. Osteoradionecrosis can be minimized by oral evaluation and care prior to irradiation and healing time which allows tissue repair until the commencement of radiotherapy. In dental extractions realized after irradiation, minimal trauma, alveolectomy, primary alveolar closure and adjunctive therapies are recommended. Patients must be evaluated before radiation therapy and at that time all unrestorable teeth and/or teeth with periodontal problems must be extracted to reduce the post-radiotherapy exodontias that contribute to ORN. Once dental extractions become unavoidable after irradiation, additional care is needed.

Implant stability during osseointegration in irradiated and non-irradiated minipig alveolar bone: an experimental study

OBJECTIVES

Primary implant stability is related to local bone density. After insertion of an implant, implant stability is subject to changes due to bone remodeling. In patients who have undergone radiotherapy in the head and neck region, implant stability is impaired because irradiation reduces bone vitality. The current study was designed to monitor and test implant stability immediately after implant placement and during osseointegration in irradiated and non-irradiated minipig alveolar bone.

MATERIALS AND METHODS

All maxillary and mandibular premolars and molars of six adult Göttingen minipigs were extracted. The maxilla and mandible of three minipigs received three irradiation exposures at a total dose of 24 Gy. After irradiation, five initial implant holes were drilled in the residual alveolar ridge of each edentulous site. In order to assess bone vascularity, laser Doppler flowmetry recordings were carried out in the initial holes. A total of 120 implants were placed in the six minipigs. Subsequently, and at 8, 16, and 24 weeks after implant placement, implant stability was recorded by resonance frequency analysis (RFA). RFA values were expressed as an implant stability quotient (ISQ).

RESULTS

ISQ values recorded immediately after implant placement showed no differences between irradiated and non-irradiated minipigs. Repeated measurements at the four recording moments showed a decrease of ISQ values in all minipigs, being more pronounced in irradiated bone, when compared with non-irradiated bone. The results at the third and fourth recording moments showed a stabilization or even a slight increase of ISQ values.

CONCLUSIONS

The results document the negative effect of irradiation on bone vascularity and hence on implant stability.

Osteoradionecrosis prevention myths

PURPOSE

To critically analyze controversial osteoradionecrosis (ORN) prevention techniques, including preradiation extractions of healthy or restorable teeth and the use of prophylactic antibiotics or hyperbaric oxygen (HBO) treatments for preradiation and postradiation extractions.

METHODS

The author reviewed ORN studies found on PubMed and in other article references, including studies on overall ORN incidence and pre- and postradiation incidence, with and without prophylactic HBO or antibiotics.

RESULTS

Owing in part to more efficient radiation techniques, the incidence of ORN has been declining in radiation patients over the last 2 decades, but the prevention of ORN remains controversial. A review of the available literature does not support the preradiation extraction of restorable or healthy teeth. There is also insufficient evidence to support the use of prophylactic HBO treatments or prophylactic antibiotics before extractions or other oral surgical procedures in radiation patients.

CONCLUSIONS

To prevent ORN, irradiated dental patients should maintain a high level of oral health. A preradiation referral for a dental evaluation and close collaboration by a multidisciplinary team can be invaluable for radiation patients. As with most other dental patients, restorable and healthy teeth should be retained in irradiated patients. The use of prophylactic HBO or antibiotics should be reconsidered for preradiation and postradiation extractions.

Osteoradionecrosis of the mandible

PURPOSE OF REVIEW

Osteoradionecrosis of the mandible is a serious complication of radiation therapy to the head and neck. Given the increased use of radiation therapy and combined chemotherapy-radiation therapy regimens in treatment of head and neck malignancies, it is anticipated that osteoradionecrosis will continue to be an important clinical problem. Recently, new concepts have been introduced regarding the pathogenesis of osteoradionecrosis, and these ideas help outline new guidelines for treatment.

RECENT FINDINGS

Current literature focuses on the probability of a fibroatrophic mechanism for the development of osteoradionecrosis, rather than the traditional vascular insufficiency mechanism. Because of the evolution of this new idea, as well as a double-blinded, placebo-controlled study finding no benefit from the use of hyperbaric oxygen for advanced osteoradionecrosis of the mandible, new treatment considerations have emerged. Ongoing research is also being conducted to clarify the role of osteoclasts in the pathogenesis of osteoradionecrosis. Restoration of blood supply or vascularized tissue to the affected area continues to be of primary importance in the resolution of osteoradionecrosis.

SUMMARY

It is clear that the cause and pathogenesis of osteoradionecrosis are far more complex than originally believed. Current and future research on this multifaceted topic will focus on the cellular basis of this condition, because as it is elucidated, more effective medical treatment regimens will become evident.

Aseptic osteonecrosis in children and adolescents treated for hemato-oncologic diseases: a 13-year longitudinal observational study

Aseptic osteonecrosis (AON) is a serious long-term complication of childhood cancer therapy. A retrospective study was undertaken to describe treatment and long-term follow-up of patients with AON. Between 1990 and 2003, 630 consecutive children with various malignancies were treated at the University Children's Hospital in Graz, Austria. In nine of these patients presenting with skeletal symptoms, MRI revealed AON. All nine had hematologic malignancies. The median age at diagnosis of malignancy was 15.8 years (range 13.7-18.6 years), and the median interval between diagnosis of malignancy and onset of osteonecrosis-related symptoms was 16 months (range 6-53 months). All patients had received previous corticosteroid therapy. Treatment of AON included restriction of weight-bearing, physiotherapy, and analgesics. Three patients were treated with hyperbaric oxygen therapy combined with the prostacyclin analog iloprost, and one patient also received pamidronate, a second-generation bisphosphonate. This conservative treatment resulted in alleviation of symptoms in all patients. One patient had to undergo bilateral hip replacement and two had to undergo arthrotomy with sequestrotomy due to subsequent deterioration of symptoms. Close monitoring for skeletal symptoms is mandatory during follow-up of patients with hematologic malignancies. Previous corticosteroid treatment and age older than 10 years seem to be major risk factors. Early detection of AON leading to prompt intervention may prevent more severe morbidity.

Hyperbaric oxygen therapy in the treatment of radio-induced lesions in normal tissues: a literature review

Late complications are one of the major factors limiting radiotherapy treatment, and their treatment is not codified. Hyperbaric oxygen (HBO) has been used in combination with radiotherapy for over half a century, either to maximise its effectiveness or in an attempt to treat late complications. In this latter case, retrospective trials and case reports are prevailing in literature. This prompted European Society for Therapeutic Radiotherapy and Oncology and European Committee for Hyperbaric Medicine to organise a consensus conference in October 2001, dealing with the HBO indications on radiotherapy for the treatment and prevention of late complications. This updated literature review is part of the documents the jury based its opinion on. A systematic search was done on literature from 1960 to 2004, by only taking into account the articles that appeared in peer review journals. Hyperbaric oxygen treatment involving complications to the head and neck, pelvis and nervous system, and the prevention of complications after surgery in irradiated tissues have been studied. Despite the small number of controlled trials, it may be indicated for the treatment of mandibular osteoradionecrosis in combination with surgery, haemorrhagic cystitis resistant to conventional treatments and the prevention of osteoradionecrosis after dental extraction, whose level of evidence seems to be the most significant though randomised trials are still necessary. The other treatment methods are also outlined for each location.

Clinical implications of radionecrosis to the head and neck surgeon

Radiation necrosis is one of the most serious complications in the treatment of malignancies of the head and neck. As radiotherapy becomes more frequently used as a primary modality and in combination with chemotherapy and surgery, the head and neck surgeon needs to be able to prevent and recognize the often subtle signs and symptoms of radiation necrosis. The symptoms of necrosis can mimic the recurrence of cancer, which presents a diagnostic dilemma, because aggressive surgical biopsy may worsen necrosis and contribute to the formation of a fistula. This review provides a brief discussion of the diagnostic and treatment options for osteoradionecrosis and chondroradionecrosis in the head and neck.

Radiotherapy-induced mandibular bone complications

The mandible is among the bones most frequently affected by irradiation. The most severe post-radiation injury of the mandible is osteoradionecrosis (ORN). Conflicting data have been reported on the incidence of this complication, its aetiology and management. The incidence of mandibular ORN in head and neck cancer patients managed with radical or postoperative irradiation, has varied widely in the literature from 0.4% to 56%. The interpretation of data derived from particular series are difficult due to the different scoring methods and classification systems used for the evaluation of post-radiation bone damage. Although ORN occurs typically in the first three years after radiotherapy, patients probably remain at indefinite risk. The diagnosis of ORN is principally based on the clinical picture of chronically exposed bone. Radiological symptoms include decreased bone density with fractures, cortical destruction and loss of spongiosa trabeculation. Numerous factors that may be associated with the risk of ORN include treatment-related variables (for example, total radiotherapy dose, biologically effective dose, photon energy, brachytherapy dose rate, combination of external beam irradiation and interstitial brachytherapy, field size, fraction size, volume of the mandible irradiated with a high dose), patient-related variables (like deep parodontitis, pre-irradiation bone surgery, bad oral hygiene, alcohol and tobacco abuse, bone inflammation, dental extraction after radiotherapy) and tumour-related factors (tumour size or stage, proximity of the tumour to bone, anatomic tumour site). Primary management of post-radiation bone lesions include conservative modalities such as saline irrigations, antibiotics during infectious episodes, topically applied antiseptics, gentle sequestrectomy and removal of visibly loosened bone elements as well as treatment with hyperbaric oxygen (HBO). Surgery is reserved for persistent ORN and includes radical resection of the lesion(sequestrectomy, hemimandibulectomy etc.) with reconstruction. In recent years the introduction of preventive oral hygiene measures and meticulous dental evaluations before and after irradiation, improvement in radiotherapy techniques and the development of reliable diagnostic and therapeutic procedures have resulted in a decreased incidence of ORN. Nevertheless, given the severe impact of ORN on patient quality of life, research should be continued to further ameliorate this problem.