Fibular free flap necrosis after mandibular reconstruction surgery with osteoradionecrosis: Establishment and verification of an early warning model

OBJECTIVE

Fibular free flap necrosis (FFFN) is the most common complication in patients with osteoradionecrosis (ORN) after mandibular reconstruction surgery. However, there are no effective forecasting tools at present. This research is aimed to establish and verify a nomogram model to predict the risk of FFFN after mandibular reconstruction surgery in ORN patients.

METHODS

A total of 193 ORN patients with mandibular reconstruction using fibular free flap (150 cases in the model group and 43 cases in the validation group) were enrolled in this study. In the model group, the variables were optimized by lasso regression. Then the prediction model was established by binary logistic regression analysis, and the nomogram was drawn. The bootstrap self-sampling method was used for internal verification. Moreover, 43 cases in the validation group were used for external validation.

RESULTS

The results of lasso regression and binary logistic regression analysis showed that the radiotherapy interval (≤2 years), trismus, diabetes, without deep venous anastomoses, and American society of anesthesiologists (ASA) III were the independent risk factors for FFFN after mandibular reconstruction surgery in ORNJ patients (P<0.05). Based on the above-mentioned risk factors, the nomogram model was established. The AUC values of the model group and the validation group were 0.936 and 0.964, respectively. The curve analysis showed that when the probability thresholds of the model group and the validation group were 5.699%∼98.229% and 0.413%∼99.721%, respectively. So the patient's clinical net profit rate was the highest.

CONCLUSION

A nomogram combining the factors of radiotherapy interval (≤2 years), trismus, diabetes, without deep venous anastomoses, and ASA III provided a comparatively effective way to predict the risk of FFFN after mandibular reconstruction surgery in ORN patients, which has distinct applied clinical value.

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.

Extranodal natural killer/T cell lymphoma nasal type simulating osteoradionecrosis with metachronic B lymphoma in the pelvis: Case report

Extranodal Natural Killer/T Cell Lymphoma Nasal Type (EN-NK/T-CL-NT) is a non-Hodgkin extranodal lymphoma of unfavorable prognosis due to its aggressive nature. This neoplasm mainly affects the paranasal sinuses, nasopharynx, oropharynx, oral cavity, palate, and rarely intestinal, gastric and skin regions. 50-year-old female with a history of lymphoma in nasal and pelvic region. At four years of tumors-free, has facial asymmetry, accompanied by sub-palpebral, nasal and lip edema. Intraoral examination revealed a large ulceration suggestive of osteoradionecrosis. Gum biopsy shows Extranodal NK/T Cell Lymphoma Nasal Type (EN-NK/T-CL-NT). In this case we highlight the characteristics of EN-NK/T-CL-NT with a presentation of osteoradionecrosis-like. Unfortunately, the nature of this tumor led to the patient's death. Clinical follow-up of patients with cancer is imperative to mend and/or decrease treatment complications, as well as to identify second primary tumors or the spread of the underlying disease.

Radiologic findings of osteonecrosis, osteoradionecrosis, osteomyelitis and jaw metastatic disease with cone beam CT

PURPOSE

The purpose of this study was to assess CBCT scans of patients with medication related osteonecrosis of the jaws (MRONJ), osteoradionecrosis (ORN), osteomyelitis (OM) and jaw metastatic disease (JM), evaluate the presence and extent of radiologic findings, identify radiologic parameters that may distinguish the four entities and last, introduce a new modified radiographic index (CRIm), in order to contribute to the diagnosis of these conditions.

METHODS

Τwo major databases were retrospectively searched for fully documented and diagnosed CBCT scans of MRONJ, ORN, OM and JM from 2006 to 2019. 335 CBCT scans met the inclusion criteria and were assessed under standardized viewing conditions blindly by 2 observers. The CRIm index proposed in this study evaluates: lytic changes, sclerosis, periosteal bone formation, sequestration, non-healing extraction sockets and other findings which included: sinus implication, inferior alveolar canal implication and jaw fracture. Lytic changes, sclerosis, periosteal bone formation, sequestration and non-healing extraction sockets were scored as: absent (0), localized/single (1) and extensive/multiple (2). Each one of other findings were scored individually as: absent (0) and present (1). For statistical analysis t-test, Pearson's r correlation coefficient, one-way ANOVA and Bonferonni were performed.

RESULTS

Extensive lytic changes were the most common finding, especially for ORN, where it occurred in all CBCT scans (100%). The mean value of the CRIm index differs significantly between CBCT scans with MRONJ and JM, as well as between those with OM and JM (Bonferroni p < 0.001).

CONCLUSIONS

The new modified Composite Radiographic Index introduced in this study, appears to have improved an objective approach to the previously used Composite Radiographic Index by means of cumulative radiologic features. Τhe predominance of certain radiologic features in one or more of these entities may lead the diagnostician towards the correct diagnosis.

Comparison of maximum and mean standardized uptake values of jaw pathologies with bone SPECT/CT: an especial focus on medication-related osteonecrosis of the jaw

OBJECTIVES

To investigate the comparison of maximum and mean standardized uptake values (SUVs) of jaw pathologies with bone Single-photon emission computed tomography/computed tomography (SPECT/CT), and a special focus on medication-related osteonecrosis of the jaw (MRONJ).

METHODS

Eighty-nine patients with jaw pathologies (63 MRONJ, 13 chronic osteomyelitis, 11 osteoradionecrosis and 2 primary intraosseous carcinoma) underwent bone SPECT/CT scans acquisition at 4 h after intravenous injection of Tc-99m hydroxymethylene diphosphonate in this prospective study. The evaluation of mean and maximum SUVs of jaw pathologies were performed using Q. Metrix and Xeleris workstation and defined the data automatically. Statistical analyses were performed by Pearson's correlation coefficient for comparison of maximum and mean SUVs and Mann-Whitney U-test for SUVs of MRONJ. A P value lower than 0.05 was considered to indicate statistical significance.

RESULTS

Maximum SUVs of MRONJ, chronic osteomyelitis, osteoradionecrosis and primary intraosseous carcinoma were 17.6 ± 8.4, 21.7 ± 7.1, 11.9 ± 4.8 and 26.6 ± 7.0, respectively. Mean SUVs of MRONJ, chronic osteomyelitis, osteoradionecrosis and primary intraosseous carcinoma were 10.1 ± 4.9, 11.9 ± 3.3, 7.0 ± 2.8 and 10.1 ± 4.5, respectively. The maximum SUV of jaw pathologies was significantly correlated with the mean SUV (Y = 0.494X + 1.228; R2 = 0.786; P < 0.001). Furthermore, maximum and mean SUVs of MRONJ had significant differences in underlying diseases, medication and staging.

CONCLUSION

The maximum and mean SUVs with bone SPECT/CT can be an effective tool for the quantitative evaluation of jaw pathologies, especially MRONJ.

Osteoradionecrosis of the Cervical Spine: An Analysis of the Literature

OBJECTIVES

The purpose of this manuscript is to review the current literature on osteoradionecrosis of the cervical spine (C-ORN) and to summarize the risk factors, presenting symptoms and management strategies of this rare condition.

STUDY DESIGN

A systematic review of the literature on C-ORN was completed using PubMed. Nineteen articles met criteria; 97 patient cases were identified. Statistical analysis was completed from the patient cases.

RESULTS

Of the analyzed patients, 72% are male and 28% are female with an average age of 57.7 years. Nasopharyngeal carcinoma was the most common initial diagnosis (72%). Thyroid and other lower neck cancers were associated with a later onset of C-ORN compared with other cancers. C-ORN more commonly occurred in the clivus to C2 (55.3%, P = .004). Onset of C-ORN significantly differed for men (n = 6.99 years) and women (n = 17.5 years) (P = .022).

CONCLUSION

C-ORN can be a devastating complication of head and neck radiation therapy. C-ORN is associated with nasopharyngeal carcinoma, and most commonly affects the area of the clivus to cervical vertebrae C2. Cancers of the lower neck and female sex are associated with later onset. Initial presentation ranges from asymptomatic to severe neurologic deficits; the degree of intervention should be congruent with the severity of presenting symptoms. As long-term survival of patients with head and neck cancer increase, this complication may become more prevalent.

18F-FDG PET/CT in Osteoradionecrosis of the Hyoid

Osteoradionecrosis (ORN) is a well-documented complication following radiation treatment for head and neck malignancy. Facial bones, mainly the mandible, laryngeal cartilage, and skull, are frequently involved sites for ORN. A rare site for ORN is the hyoid, with very limited cases described in the literature. Recognition of the imaging pattern of hyoid ORN is critical to avoid misdiagnosis of recurrent disease, prompting early treatment.

Quantitative Dynamic Contrast-Enhanced MRI Identifies Radiation-Induced Vascular Damage in Patients With Advanced Osteoradionecrosis: Results of a Prospective Study

PURPOSE

We aim to characterize the quantitative dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) parameters associated with advanced mandibular osteoradionecrosis (ORN) compared with the contralateral normal mandible.

METHODS AND MATERIALS

Patients with a diagnosis of advanced ORN after curative-intent radiation treatment of head and neck cancer were prospectively enrolled after institutional review board approval and study-specific informed consent were obtained. Quantitative maps generated with the Tofts and extended Tofts pharmacokinetic models were used for analysis. Manual segmentation of advanced ORN 3-dimensional volume was done using anatomic sequences to create ORN volumes of interest (VOIs). Subsequently, normal mandibular VOIs were segmented on the contralateral healthy mandible of similar volume and anatomic location to create control VOIs. Finally, anatomic sequences were coregistered to DCE sequences, and contours were propagated to the respective parameter maps.

RESULTS

Thirty patients were included. The median time to ORN diagnosis after completion of IMRT was 38 months (range, 6-184 months), whereas median time to ORN progression to advanced grade after initial diagnosis was 5.6 months (range, 0-128 months). There were statistically significant higher K^trans and V_e in ORN-VOIs compared with controls (0.23 vs 0.07 min^-1, and 0.34 vs 0.15; P < .0001 for both). The average relative increase of K^trans in ORN-VOIs was 3.2-fold higher than healthy mandibular control VOIs. Moreover, the corresponding rise of V_e in ORN-VOIs was 2.7-fold higher than in the controls. Using combined K^trans and V_e parameters, 27 patients (90%) had at least a 200% increase of either of the studied parameters in the ORN-VOIs compared with their healthy mandible VOIs.

CONCLUSIONS

Our results confirm that there is a quantitatively significant higher degree of leakiness in the mandibular vasculature as measured using DCE-MRI parameters of areas with advanced ORN versus healthy mandible.

Challenges threaten, opportunity awaits hyperbaric medicine and the head and neck cancer patient

Over the past four decades, hyperbaric oxygen (HBO2) therapy has played a prominent role in both the prevention and treatment of mandibular osteoradionecrosis (ORN). It has done so on the strength of laboratory observations and clinical reports, yet only limited efficacy data. This dual role has come under increasing scrutiny in the modern radiotherapy (RT) and surgical eras. The ability to spare healthy "non-target" tissue has markedly improved since the two-dimensional planning and delivery techniques in use when HBO2's prophylactic value was first demonstrated. A recent study failed to identify this same benefit in patients who received high-precision imaging and conformal RT. HBO2 therapy is under challenge as preferred treatment for early stage ORN. A recently introduced "fibroatrophic" mechanism contrasts with the hypovascular-hypocellular-hypoxic injury pattern that formed the basis for HBO2's therapeutic use. This alternative pathophysiologic state appears to benefit from an oral antioxidant medication regimen. The continuing necessity of HBO2 in support of mandibular reconstruction for advanced ORN is in question. Microsurgery-based vascularized bone flaps increasingly represent standard care, invariably in the absence of perioperative HBO2. Renewed interest in hyperbaric oxygen as a radiation sensitizer offers some promise. Hypoxia remains a critical radio-resistant factor in many solid tumors. Malignant gliomas have been a primary focus of several small studies, with resulting improvements in local control and median survival. Hyperbaric radiation sensitization has recently addressed oropharyngeal cancer. Preliminary data indicates that addition of HBO2 to chemo-radiation standard of care is technically feasible, well tolerated and safe. A Phase II efficacy trial will investigate the potential for of HBO2 to improve progression-free and relapse-free survival in newly diagnosed locally advanced head and neck cancers. What follows is a review and summary of relevant peer-reviewed literature.

Association between pain severity and clinicohistopathologic findings in the mandibular canal and inferior alveolar nerve of patients with advanced mandibular osteoradionecrosis

OBJECTIVE

Pain is one of the most problematic symptoms in patients with osteoradionecrosis of the jaws. This study investigated the associations between pain severity and morphologic alterations of the mandibular canal and inferior alveolar nerve, in respective computerized tomography images and resected specimens of mandibular osteoradionecrosis.

STUDY DESIGN

We assessed 14 lesions in 13 patients who underwent segmental mandibulectomy for surgical debridement and simultaneous reconstruction with free fibula flap (1 patient exhibited bilateral lesions). The extent of the mandibular canal bone defect on preoperative coronal computerized tomography images and the number of inferior alveolar nerve fascicles in resected specimens were evaluated. Comparisons were made between the slight pain and extreme pain groups. In most of the patients in the extreme pain group, either mandibular canal bone defects were absent or entire circumferential defects were present; inferior alveolar nerve fascicles were either distinguishable or completely absent in the resected specimens.

RESULTS

Although there was no statistically significant association between extreme pain and computerized tomography or histopathologic findings, the histopathologically indistinguishable inferior alveolar nerve fascicles was significantly associated with slight pain.

CONCLUSIONS

The degree of degeneration of mandibular canal and inferior alveolar nerve may be associated with pain severity in patients with mandibular osteoradionecrosis.

Heterogeneity of Necrotic Changes between Cortical and Cancellous Bone in Mandibular Osteoradionecrosis: A Histopathological Analysis of Resection Margin after Segmental Mandibulectomy

BACKGROUND

This study aimed to analyze differences in necrotic changes between cortical and cancellous bone in resection margins after segmental mandibulectomy for advanced mandibular osteoradionecrosis.

METHODS

Anteroposterior bone specimens from eleven patients who underwent segmental mandibulectomy with simultaneous free fibula flap reconstruction for advanced osteoradionecrosis were analyzed histopathologically for the presence of necrotic bone based on the presence of blood vessels within Haversian canals.

RESULTS

Ten of eleven (91%) cortices near the inferior border of the mandible at the anterior margins were necrotic. All cancellous bones at the anterior margins were viable. Seven of eleven (64%) cortices near the inferior border of the mandible at the posterior margins were necrotic. Three of eleven (27%) cancellous bones at the posterior margins were necrotic.

CONCLUSION

Necrotic changes are more prevalent in cortices than in cancellous bones in mandibular osteoradionecrosis, probably due to a decrease of periosteal blood supply caused by radiotherapy.

MD Anderson Head and Neck Cancer Symptom Working Group. Dose-volume correlates of mandibular osteoradionecrosis in Oropharynx cancer patients receiving intensity-modulated radiotherapy: Results from a case-matched comparison

PURPOSE

To determine dosimetric parameters associated with osteoradionecrosis (ORN) in oropharyngeal cancer (OPC) patients in the IMRT era.

MATERIAL AND METHODS

Subsequent to institutional review board approval, we identified ORN in OPC patients treated with IMRT from 2002 to 2013. 1:2 case-control matching was implemented. Mandibular dose-volume histograms (DVH) were extracted. Dosimetric parameters were compared using non-parametric stats. Recursive partitioning analysis (RPA) was done to identify DVH correlates of ORN.

RESULTS

68 ORN cases and 131 controls were matched. Median follow-up was 41months and median time to development of ORN was 16months. Mandibular mean dose was significantly higher in the ORN cohort (48.1 vs 43.6Gy, p<0.0001). However, the maximum dose was not statistically different. DVH bins from V35 to V73 were all significantly higher in the ORN cohort compared with controls (p<0.0006). Two DVH parameters were identified in RPA analysis, V43 and V58. The majority (81%) of ORN cases were observed with both V44≥42% and V58≥25%.

CONCLUSIONS

Our data demonstrate that a wide range of DVH parameters in the intermediate and high beam path were all significantly higher in ORN patients. Mandibular V44<42% and V58<25% represent reasonable DVH constraints for IMRT plan acceptability, when tumor coverage is not compromised.

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.

Role of parathyroid hormone in regeneration of irradiated bone in a murine model of mandibular distraction osteogenesis

BACKGROUND

The purpose of this study was to measure the histologic and histomorphometric effects of parathyroid hormone (PTH) treatment on irradiated bone undergoing distraction osteogenesis (DO).

METHODS

Thirty-four rats were divided into 3 groups. The control group underwent DO and the radiation control group underwent radiotherapy (RT) before DO. The PTH group underwent RT and received PTH during DO. Quantitative histology and histomorphometry were performed.

RESULTS

RT resulted in a depletion of osteocytes and increase in empty lacunae. Treatment with PTH resulted in an increase in osteocyte counts and decrease in empty lacunae (p < .05), restoring osteocytes to levels seen in nonradiated bone (p = .121). RT decreased bone volume to tissue volume (BV-TV) ratio and increased osteoid volume to tissue volume (OV-TV) ratio, signifying increased immature bone formation. PTH treatment restored OV-TV ratio to that observed in nonradiated bone.

CONCLUSION

PTH treatment of irradiated bone enhanced bone regeneration and restored osteocyte counts and OV-TV ratio to levels comparable to nonradiated bone. © 2016 Wiley Periodicals, Inc. Head Neck 39: 464-470, 2017.

Radiation-Induced Petrous Internal Carotid Artery Aneurysm

Iatrogenic internal carotid artery aneurysm is a rare complication of irradiation. There are few reported cases in the literature. A case of radiation-induced petrous internal carotid artery aneurysm in a patient with nasopharyngeal cancer treated with radiotherapy is reported. The approach to managing such an aneurysm is discussed.

Raman spectroscopy delineates radiation-induced injury and partial rescue by amifostine in bone: a murine mandibular model

Despite its therapeutic role in head and neck cancer, radiation administration degrades the biomechanical properties of bone and can lead to pathologic fracture and osteoradionecrosis. Our laboratories have previously demonstrated that prophylactic amifostine administration preserves the biomechanical properties of irradiated bone and that Raman spectroscopy accurately evaluates bone composition ex vivo. As such, we hypothesize that Raman spectroscopy can offer insight into the temporal and mechanical effects of both irradiation and amifostine administration on bone to potentially predict and even prevent radiation-induced injury. Male Sprague-Dawley rats (350-400 g) were randomized into control, radiation exposure (XRT), and amifostine pre-treatment/radiation exposure groups (AMF-XRT). Irradiated animals received fractionated 70 Gy radiation to the left hemi-mandible, while AMF-XRT animals received amifostine just prior to radiation. Hemi-mandibles were harvested at 18 weeks after radiation, analyzed via Raman spectroscopy, and compared with specimens previously harvested at 8 weeks after radiation. Mineral (ρ958) and collagen (ρ1665) depolarization ratios were significantly lower in XRT specimens than in AMF-XRT and control specimens at both 8 and 18 weeks. amifostine administration resulted in a full return of mineral and collagen depolarization ratios to normal levels at 18 weeks. Raman spectroscopy demonstrates radiation-induced damage to the chemical composition and ultrastructure of bone while amifostine prophylaxis results in a recovery towards normal, native mineral and collagen composition and orientation. These findings have the potential to impact on clinical evaluations and interventions by preventing or detecting radiation-induced injury in patients requiring radiotherapy as part of a treatment regimen.

Management of osteonecrosis of the jaws induced by radiotherapy in oncological patients: preliminary results

OBJECTIVE

Osteoradionecrosis (ORN) is a bone aseptic necrosis which develops on post-irradiated bone tissue of patients who underwent radiotherapy for head-neck tumors. The mandible presents a higher risk to develop ORN, if compared to the maxillary bone, due to its lower vascularization. The aim of the present study is to clinically assess the regenerative ability by the epithelial and connective tissues, in response to ORN onset.

PATIENTS AND METHODS

Authors have verified the importance of the surgical-pharmacological treatment, as an effective protocol for eliminating the exposed bone sequestration, as well as the teeth eventually damaged by the radiotherapy, assessing that the epithelium can regenerate only on healthy and vital tissues.

RESULTS

The reported patient underwent resection of a portion of the left mandible with an incomplete healing after the surgery. A second curettage was scheduled in order to remove the bands of necrotic tissue and to obtain a clinical remission of symptoms.

CONCLUSIONS

In patients undergoing radiotherapy, the dental surgeon should be able to give an early diagnosis of the dental and maxillofacial related pathologies; he should also detect all the possible infective sources and administer any possible treatment in a short time, before the beginning or the prosecution of radiotherapy.

Osteo-radio-necrosis (ORN) and bisphosphonate-related osteonecrosis of the jaws (BRONJ): the histopathological differences under the clinical similarities

OBJECTIVES

Both osteoradionecrosis (ORN) and bisphosphonate associated osteonecrosis of the jaws (BRONJ) present clinically as regions of exposed necrotic bone. The study aimed to demonstrate the histopathological differences behind the observed clinical similarities.

STUDY DESIGN

Ten ORN specimens and ten BRONJ specimens were used, as well as ten samples of normal mandibular bone as control. Two bone-specific stainings were used, i.e. Sirius Red for the study of the relative presence of collagen types I and III and toluidine blue for the study the osteon density.

RESULTS

The Red Green Blue (RGB)-analysis of the specimens stained with Sirius Red identified significant differences between the chromatic patterns observed in bone preparations of patients suffering from ORN when compared to both BRONJ and control samples. Moreover, the osteon density of the BRONJ samples was significantly lower when compared to ORN and normal bone samples.

CONCLUSIONS

The demonstrated differences in the bone architecture and in the bone collagen content between the two pathological conditions most likely reflect underlying pathophysiological differences.

Sternoclavicular osteoradionecrosis following treatment for head and neck cancer

Osteoradionecrosis (ORN) is a well described complication of radiation therapy (RT) for head and neck cancer (HNC), with a past reported incidence as high as 10-18% [1,4] mostly involving the mandible. ORN rarely involves the sternoclavicular complex in HNC patients treated with RT. Here, we present a case of HNC treated with combined (cytotoxic) chemotherapy and radiation therapy (CCRT) complicated by ORN and osteomyelitis of the sternoclavicular complex involving large segments of both clavicles, the sternum, and the trachea.

A model of mandibular irradiation in the rabbit: preliminary results

Radiotherapy is widely used in the treatment of head and neck cancers. Its major adverse effect is osteoradionecrosis, which can occur during the whole life of the patient, involving the vital prognosis. The aim of the study was to develop a model for irradiation of the rabbit mandible in order to have a better knowledge of radiotherapy-induced bone alterations and thus a better prevention and treatment of osteoradionecrosis. The control group consisted in 7 rabbits and was used to assess anatomical and histological parameters of the rabbit's mandible. A first group of 14 rabbits was weekly irradiated at doses of 5.5 Gy during 5 weeks, at a total dose of 46.8Gy. Sacrifices were done at 1 week, 4 weeks, 12 weeks and 24 weeks. As histological analysis did not reveal statistical differences with the control group, a second group (3 rabbits) was weekly irradiated at 8.0, 8.5 and 9 Gy during 5 weeks. The first histological results seem to show vascular alterations, bone cells decrease and alterations of bone architecture. The role of intra alveolar collagen sponges, PRF®, ultrasounds and stem cells in bone regeneration after radiotherapy will be further studied.

Long-term results of brachytherapy in early mobile tongue cancer with 10-year minimal follow-up

AIM

To retrospectively analyze the long-term toxicities of low-dose-rate interstitial brachytherapy (LDR-BT) with related prognostic factors for patients with early mobile tongue cancer (T1/2N0M0) at a minimum of 10 years' follow-up.

PATIENTS AND METHODS

The records of 187 patients treated with LDR-BT between 1980 and 2000, out of whom 25 were treated with additional prior external beam irradiation, were reviewed.

RESULTS

Overall survival at 15 and 20 years was 88.4% and 76.2%, respectively. Complications included tongue ulcer (26%), tongue erosion (3%), tongue atrophy (2%), bone exposure (15%), and osteoradionecrosis (4%). No patient presented xerostomia or taste disorders. Multivariate analysis revealed that tongue ulcer and the use of spacer were significantly associated with bone exposure and osteoradionecrosis. Local recurrence was demonstrated in 15 (8%) cases, 93% of which were salvaged by operation. Fifty patients (27%) experienced neck metastasis.

CONCLUSION

LDR-BT is an acceptable treatment option, with low rates of long-term toxicity.

Cervical spine complications after treatment of nasopharyngeal carcinoma

PURPOSE

Radiotherapy has been the mainstay treatment for nasopharyngeal carcinoma (NPC) and has achieved good disease control. However, irradiation is associated with potential complications such as osteoradionecrosis (ORN) and infection. There is sparse description in the literature of such complications and how they are best managed. The objectives of the study are: (1) to describe the complications at the cervical spine after surgical and radiotherapy treatment for NPC (2) to identify key principles in the diagnosis and treatment of these complications.

METHODS

A retrospective review of all patients with cervical spine complications after radiation treatment and surgery for NPC treated in a tertiary referral center, since 1990.

RESULTS

Fourteen patients with cervical spine ORN and infections were found with an average duration to diagnosis of 8.6 years. All 14 patients had mucosal and deep biopsies and none had tumor recurrence. Four patients had ORN, eight had osteomyelitis and two patients had both ORN and osteomyelitis.

CONCLUSIONS

Radiotherapy complications usually have delayed and subtle presentations. ORN progresses slowly and can often be treated conservatively. Infections should be treated aggressively with surgical debridement and the results are generally good. Patients should be regularly followed-up with transoral examination to assess the integrity of the posterior pharyngeal wall and imaging to assess for ORN. Pharyngeal defects raise concern for cervical spine infections. Coverage of pharyngeal defects in these patients is important to prevent recurrent infection.

Hyperbaric oxygen therapy and delayed radiation injuries (soft tissue and bony necrosis): 2012 update

Informal surveys at CME meetings have shown that approximately one-third of patients in the United States receive hyperbaric oxygen (HBO2) for delayed radiation injury. More than 600,000 patients receive radiation for malignancy in our country annually, and about one-half will be long-term survivors. Serious radiation complications occur in 5-10% of survivors. A large population of patients is therefore at risk for radiation injury. HBO2 has been applied to treat patients with radiation injury since the mid-1970s. Published results are consistently positive, but the level of evidence for individual publications is usually not high level, consisting mostly of case series and case reports. Only a rare randomized controlled trial has been accomplished. Radiation injury is one of the UHMS "approved" indications, and third-party payors will usually reimburse for this application. This updated review summarizes the publications available reporting results in treating radiation-injured patients. Mechanisms of HBO2 in radiation injury are discussed briefly. Outcome is reported on a mostly anatomic basis though due to the nature of the injury a positive outcome at one anatomic site is supportive of HBO2 at other sites. The potential benefit of prophylactic HBO2 before frank damage is also discussed in high-risk patients. The concerns of HBO2 enhancing growth of or precipitating recurrence of malignancy is discussed and largely refuted.

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.

Massive osteoradionecrosis of facial bones and soft tissues

Osteoradionecrosis (ORN) is one of the most serious and uncommon complications in head and neck irradiation for cancer. It is defined as a combination of necrotic soft tissue and bone not being able to heal spontaneously, it demonstrates a general resistance to antibiotics and requires conservative surgical management. Even with modern radiation therapy, its incidence is highly unpredictable and varies between 4-30%. We report on a patient with a huge open cavitation in the cheek, communicating with the mouth and extending to contralateral periodontal gingival and temporal fossa. He had been treated with radiation therapy for nasopharyngeal cancer 5 years ago and presented with restriction of the opening of the mouth. Osteonecrosis complicated with osteomyelitis was evident in bilateral mandible and maxillary bones and the temporal bone. The ramus of the mandible and zygomatic arc were resected, subtotal maxillectomy was performed and the defect was repaired by a free double island flap from the scapular and parascapular osteocutaneous latissimus dorsi muscle flap supplied by subscapular artery. To our knowledge, this is the most extensive bone and soft tissue destruction due to radiation reported in the literature.

A preliminary investigation into the effects of X-ray radiation on superficial cranial vascularization

Radiation therapy (RT) is an established treatment modality for malignant neoplasms. RT induces tissue damage that may lead to osteoradionecrosis in more severe cases. Suitable animal models to study RT-induced changes in membranous craniofacial bone are currently not available. The aim of this study was therefore to quantify RT-induced changes in cranial microcirculation using a newly developed calvaria chamber model and to relate these changes to RT-induced histological damage. New Zealand white rabbits received a total radiation dose of 18.75 Gy through the calvaria chamber, and the number of vessels, the vessel length density (VLD), and angiogenic sprouting were quantified on a weekly basis during a 12-week period. At the end of 12 weeks, the RT-treated (n = 5) or control (n = 5) calvarias were biopsied for histopathological analysis. RT resulted in a steep reduction in the number of vessels and the VLD during the first 3 weeks, particularly in larger-diameter vessels, followed by a flat stabilization/remodeling phase in the subsequent 9 weeks that never restored to baseline values. Histomorphometric analysis revealed a high degree of osteocytic depletion, prominent hypocellularity in the lacunae and intraosseous vasculature, enlarged and nonconcentric Haversian systems, and a severely disorganized bone matrix in the RT-treated calvarias. Despite the prevalence of some angiogenic potential, the RT-induced effects in the early phase persisted in the intermediate to late phase, which may have contributed to the poor recovery of the RT-treated bone.

Tension pneumocephalus--a rare complication of radiotherapy: a case report

We present a rare case of tension pneumocephalus due to high-dose radiotherapy used to treat nasopharyngeal carcinoma. A skull base defect causing tension pneumocephalus was identified and was repaired successfully. The case emphasizes the importance of careful consideration before applying irradiation treatment to patients with head and neck malignancy and urges early detection of potentially life-threatening complications.

[Surgical treatment of diffused osteoradionecrosis of temporal bone in cases with nasopharyngeal carcinoma after radiotherapy]

OBJECTIVE

To investigate the effective treatment method of osteoradionecrosis (ORN) of temporal bone in the patients with nasopharyngeal carcinoma (NPC) after radiotherapy.

METHODS

Eight NPC patients (8 ears) with ORN of temporal bone accepted surgical treatment, 2 ears undergoing radical mastoidectomy, 2 ears undergoing extensive radical mastoidectomy, 5 ears undergoing radical mastoidectomy and obliteration with transferring local vascularized fascia flaps.

RESULTS

Five of the 8 ears (62.5%) achieved dry ear, including 4 ears undergoing radical mastoidectomy and obliteration with vascularized fascia flaps, and 1 ear undergoing radical mastoidectomy. Two of the 8 ears (25%) still had infection and were not fully epithelized, but without sequestration, including 1 ear undergoing mastoidectomy and obliteration with vascularized fascia flaps, and 1 ear undergoing extensive radical mastoidectomy. One of the 8 ears (12.5%) which had received radical mastoidectomy needed revision surgery because of re-sequestration.

CONCLUSION

The surgical treatment for diffused ORN of temporal bone by radical mastoidectomy and obliteration with local vascularized flaps is effective. The main objective of the surgery is get excellent drainage and prevention of complications.

Increased numbers of osteoclasts expressing cysteine proteinase cathepsin K in patients with infected osteoradionecrosis and bisphosphonate-associated osteonecrosis—a paradoxical observation?

Erosion of the bone is a common problem in patients suffering from infected osteoradionecrosis (IORN) or bisphosphonate-associated osteonecrosis (BON). Besides inflammatory mechanisms and infectious agents, osteoclasts were recently suggested to be specifically involved in the osteolytic mechanisms. We therefore investigated the immunohistochemical labeling of the cysteine proteinase cathepsin K, which plays a central role in osteoclast-mediated bone resorption, in tissue specimens of patients with BON (n=9; four male, five female; mean age=69.2 years) and IORN (n=10; nine male, one female; mean age=60.5 years), and compared the results with control specimens (n=8; six male, two female; mean age=60 years). In all cases, osteoclasts were the predominant cell type expressing cathepsin K. For semiquantitative analysis, we therefore defined osteoclasts as multinuclear giant cells attached to the bone and expressing cathepsin K. Significantly higher numbers of osteoclasts were found for both types of osteonecrosis when compared with the control group (BON+IORN vs controls: P=0.0000036). Within the pathological lesions, IORN cases exhibited significantly less osteoclasts than BON (P=0.00097). Our study verified increased numbers of osteoclasts in patients suffering from BON and IORN. Although it is known that bisphosphonates (and to a lesser extent, irradiation, too) decrease osteoclast function, these findings suggest a critical involvement of osteoclasts in the mechanisms of bone destruction in the respective lesions.

Osteonecrosis of the jaws in patients treated with bisphosphonates - histomorphologic analysis in comparison with infected osteoradionecrosis

BACKGROUND

Patients treated with bisphosphonates because of bone metastases have been shown to develop osteonecrosis of the jaws. In the present study, we examined the histologic findings of these cases. As similarities between this disorder and infected osteoradionecrosis (IORN) are described, both lesions were compared.

METHODS

We investigated eight patients with bisphosphonate treatment and osteonecrosis (four female, four male; median age: 65.6 years; cancer: multiple myeloma in five patients, breast cancer in three patients; mandibular involvement in five patients, maxillar involvement in three cases), and 10 patients suffering from IORN (all male; median age: 61.3 years; cancer: squamous cell carcinoma in nine patients, adenoid cystic carcinoma in one patient; mandibular involvement in all cases). Multicentric and bilateral involvement was common in the bisphosphonate group. Histologically, the bone revealed diffuse and patchy areas of necrosis in the bisphosphonate group, while in IORN osteonecrosis was larger and not diffusely distributed.

RESULTS

In all cases, we found Actinomyces attached to the necrotic bone tissue. In five of eight bisphosphonates cases, and in six of 10 IORN cases, numerous osteoclasts could be detected close to vital bone exhibiting signs of bone resorption. Pseudoepitheliomatous hyperplasia (PH) was revealed in five of eight bisphosphonate patients, and in seven of 10 IORN patients.

CONCLUSION

We conclude that Actinomyces is involved in the chronic, non-healing inflammatory processes as a characteristic feature of both diseases. Together with the associated presence of increased osteoclast numbers, we suggest that both factors may be involved in osteolytic mechanisms.

A clinical staging system and treatment guidelines for maxillary osteoradionecrosis in irradiated nasopharyngeal carcinoma patients

PURPOSE

To develop a clinical staging system for maxillary osteoradionecrosis (ORN) in irradiated nasopharyngeal carcinoma (NPC) patients.

METHODS AND MATERIALS

The data of maxillary ORN cases among 1,758 irradiated NPC patients were analyzed. A staging system based on the degrees of bone exposure (E), infection (I), and bleeding (B) was developed. Correlations between various clinical parameters and stages of maxillary ORN and relationships between treatment modalities and outcomes at each stage were evaluated. Cumulative success of treatment and risk factors that affect treatment outcomes were analyzed.

RESULTS

The incidence of maxillary ORN was 2.7% (48/1,758). TNM stage of NPC (p < 0.001), radiation dose (p = 0.029), and tooth extraction (p < 0.001) appeared to have significant influences on disease severity. Success rates between conservative therapy and surgical treatment were not significantly different for Stage I ORN but differed significantly for Stage II (p = 0.013) and Stage III (p = 0.008) lesions. Grade 3 infection and bleeding significantly jeopardized treatment success (p = 0.043 and 0.015, respectively). The risk ratios of treatment failure for Grade 3 infection and bleeding were 2.523 (p = 0.034) and 3.141 (p = 0.027), respectively.

CONCLUSIONS

More serious maxillary ORN tended to occur in cases with more advanced NPC, higher radiation dose, and history of tooth extraction. Surgical treatment was usually required in Stage II and III ORN. The grades of infection and bleeding are important factors in guidance of treatment and prediction of outcomes.

Actinomyces in infected osteoradionecrosis—underestimated?

Infected osteoradionecrosis (IORN) is a severe complication of radiation therapy for head and neck cancer. Infected osteoradionecrosis can lead to fracture and often requires subsequent jaw resection. It is known that irradiated bone is highly susceptible to infections, mainly with Candida species and cariogenic bacteria. Only very few data exist on Actinomyces in IORN. The study population consisted of 31 patients (7 female, 24 male; median age, 58.3 years). All patients exhibited clinical and radiological signs of IORN (infection, mucosa or skin fistula, and sequestrated bone). To detect Actinomyces colonies, histological examination was performed using several staining procedures (hematoxylin-eosin, Gram, Grocott, periodic acid-Schiff). In addition, a semi-nested polymerase chain reaction (PCR) approach was designed targeting the 16S ribosomal RNA gene. We found prominent Actinomyces colonies in 20 (64.5%) of 31 patients. Most of these lesions were localized in the mandible (16/20). Most interestingly, Actinomyces were almost exclusively found attached to the necrotic bone. PCR testing confirmed the presence of Actinomyces-specific DNA sequences (Actinomyces israelii). We show that Actinomyces is considerably more frequent in IORN than previously demonstrated. We suggest that these organisms are involved in the chronic, nonhealing inflammatory processes and the purulent discharge, which are known as characteristics of IORN. It remains to be investigated whether Actinomyces could be involved in the osteolytic mechanisms. From the histopathologic perspective, detection of Actinomyces is important because these bacteria have been shown to be associated with prolonged treatment duration.

Expression of bone morphogenic protein 2/4, transforming growth factor-β1, and bone matrix protein expression in healing area between vascular tibia grafts and irradiated bone—experimental model of osteonecrosis

PURPOSE

For the surgical treatment of osteoradionecrosis after multimodal therapy of head-and-neck cancers, free vascular bone grafts are used to reconstruct osseous structures in the previously irradiated graft bed. Reduced, or even absent osseous healing in the transition area between the vascular graft and the irradiated graft bed represents a clinical problem. Inflammatory changes and fibrosis lead to delayed healing, triggered by bone morphogentic protein 2/4 (BMP2/4) and transforming growth factor (TGF)-beta(1). Given the well-known fibrosis-inducing activity of TGF-beta(1), an osteoinductive effect has been reported for BMP2/4. However, the influence of irradiation (RT) on this cytokine expression remains elusive. Therefore, the aim of the present in vivo study was to analyze the expression of BMP2/4, TGF-beta(1), collagen I, and osteocalcin in the transition area between the bone graft and the graft bed after RT.

METHODS AND MATERIALS

Twenty Wistar rats (male, weight 300-500 g) were used in this study. A free vascular tibia graft was removed in all rats and maintained pedicled in the groin region. Ten rats underwent RT with 5 x 10 Gy to the right tibia, the remainder served as controls. After 4 weeks, the previously removed tibia grafts were regrafted into the irradiated (Group 1) and nonirradiated (Group 2) graft beds. The interval between RT and grafting was 4 weeks. After a 4-week osseous healing period, the bone grafts were removed, and the transition area between the nonirradiated graft and the irradiated osseous graft bed was examined histomorphometrically (National Institutes of Health imaging program) and immunohistochemically (avidin-biotin-peroxidase complex) for the expression of BMP2/4, TGF-beta(1), collagen I, and osteocalcin.

RESULTS

Absent or incomplete osseous healing of the graft was found in 9 of 10 rats after RT with 50 Gy and in 1 of 10 of the rats with nonirradiated osseous grafts. Histomorphometrically, the proportion of osseous healing in the transition area was 17% in Group 1 and 48% in Group 2 (p = 0.001). Compared with the nonirradiated rats, reduced enchondral and perichondral ossification was found in the healing area after RT, with a reduction of BMP2/4 and osteocalcin expression. TGF-beta(1) and collagen I expression in the transition area to the irradiated osseous graft bed was significantly increased compared with that in the nonirradiated osseous graft bed.

CONCLUSION

After RT, osseous healing of vascular bone grafts is significantly reduced and may be a result of radiation-induced inhibition of BMP2/4 and osteocalcin expression. In addition, induction of TGF-beta(1) and collagen I expression occurs. Because the effects of the TGF-beta superfamily are manifold and partially unknown, additional research directions could be in the exogenous application of BMP2/4 and inhibition of TGF-beta(1) by antibody treatment to search for appropriate therapeutic approaches for improving osseous healing in the irradiated graft bed.

Osteonecrosis after arthroscopic meniscectomy using radiofrequency

The purpose of this report is to describe a case of osteonecrosis that occurred after arthroscopic meniscectomy associated with a radiofrequency device. The patient developed increasing knee pain and disability 6 months after arthroscopic meniscectomy. Magnetic resonance imaging showed subchondral osteonecrosis of both femoral condyles with cyst formation.

Aspergillosis of the temporomandibular joint following irradiation of the parotid region: a case report

We report a case of aspergillosis in the right temporomandibular joint (TMJ) with a history of parotid carcinoma and post-irradiation otitis. Previous treatment attempts with surgery and antibiotics were unsuccessful. Radical debridement of the glenoid fossae, supplemented with amphotericin B and adjunct hyperbaric oxygen (HBO) therapy, was provided to resolve the symptoms. This case report highlights the need to be aware of the possibility of invasive mycosis in immunocompromised patients.

Management of cervical metastases in advanced squamous cell carcinoma of the base of tongue

OBJECTIVE

To clarify the role of neck dissection following primary radiotherapy for treatment of squamous cell carcinoma of the base of tongue.

DESIGN

Case series.

SETTING

Academic, tertiary care medical center.

PATIENTS OR OTHER PARTICIPANTS

A consecutive series of 45 patients with biopsy-proven squamous cell carcinoma of the base of tongue and cervical metastases treated with primary radiotherapy at The University of California, San Francisco, was examined. Patients with a prior history of neck irradiation, neck dissection, or head and neck cancer within 5 years were excluded.

MAIN OUTCOME MEASURES

Overall survival and regional control.

RESULTS

Of the 45 patients treated with definitive radiotherapy, 25 (56%) achieved a complete response, 13 (29%) achieved a partial response, 4 (9%) were nonresponders, and 3 (7%) did not complete radiotherapy. Two thirds of the complete responders had N2 or N3 disease; 3 had recurrences in the neck, 1 of which was an isolated neck recurrence. Of the 13 partial responders, 5 had isolated persistence of disease, with 4 undergoing neck dissections. The only long-term survivors among the partial responders were those 4 who underwent a neck dissection. Overall survival was 50% at 3 years and 32% at 5 years. Regional control for complete responders was 84% at 5 years.

CONCLUSIONS

The low rate of isolated regional recurrence in patients with a complete response to radiotherapy supports the practice of surveillance alone in such patients. Patients with less than a complete response appear to benefit from prompt surgical salvage.

Imaging of mandibular osteoradionecrosis

Because the diagnosis of mandibular ORN can often essentially be based on clinical grounds, radiology is used for confirmation and evaluation of the extent of the bone involvement. The localization and extent of the bone destruction can be better evaluated with CT than with conventional occlusal or panoramic films. Nevertheless, plain films often provide sufficient information for patient management. Based on the clinical evaluation and plain imaging findings, a decision can be made to treat patients conservatively or surgically.

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.

Osteoradionecrosis of the mandible: scientific basis for clinical staging

Osteoradionecrosis of the mandible can be a serious complication of radiotherapy for head and neck cancer. The disorder generally presents in one of several distinct clinical variations. This is probably because of a complex interaction of etiologic factors. A clinical staging system for the disorder is described. Such a system is necessary for the conduct of clinical research, and for the development and assessment of treatment regimens.

[Mature bone radionecrosis: from recent physiopathological knowledge to an innovative therapeutic action]

Osteoradionecrosis is a severe radiotherapy (RT) injury by healing failure, late effect and spontaneously irreversible by tissue death. Histologically, it consists in a pagetoid mosaic that combines a defective osteogenesis with an osteoclastic osteolysis and more marginally an osteolytic osteolysis, turned to account to fibroblastic and collagenic fibrosis. Several pathogenic hypotheses favor sometimes a vascular hypoxic hypotheses, sometimes a fibro-atrophic hypothesis. Various events start up or favour ORN as traumatisms (dental extraction, surgery,...) or bacterian infection on fistula. In clinic, adult mature bone concerned is the mandible after head and neck RT by septic ORN, and the hip after pelvic RT by aseptic ORN. For each, epidemiology, clinic and therapeutic aspects are developed. Usual therapeutic attitudes consisted in restriction of defavorable associated events (dental extraction, infection, RT dose, chemotherapy,...) and devitalized tissue removal. Physiopathological therapeutic innovatives aspects are proposed to struggle against radiation-induced fibrosis associated and to limit bone destruction.

[Mechanical changes in bone after roentgen irradiation with low dosage]

We investigated the micromechanical properties using doses from 1 up to 7 Gray and could observe a roughening on the surface of the bone material in the microscopic range by scanning acoustic microscopic measurements. In addition, a preceding irradiation promoted an extension of microcracks during the polishing process indicating an embrittlement. After irradiation and removal of the surface layer, the SAM measurements indicate a preferential increasing of hardness of softer regions. These results are consistent with our measurements by environmental scanning electron microscopy.

Hyperbaric oxygen in the therapeutic management of osteoradionecrosis of the facial bones

This paper reviews all 17 cases of facial bone osteoradionecrosis (ORN) which were treated in Adelaide, South Australia, in a nine-year period (1987 1996). This was 1.2% of all cases of head and neck cancer treated with radiotherapy (RT). Fourteen cases received treatment following the Marx principles of staging and the protocols of hyperbaric oxygen plus or minus surgery. The three exclusions were two patients who died of recurrent cancer before treatment was complete and one who declined treatment. The eleven cases of mandibular ORN occurred within a few years of the initial RT treatment. All except one occurred after surgical trauma, with dental extractions being the factor in nine cases. All responded to HBO, with or without surgery depending on stage. The three cases of temporal bone ORN were all of late spontaneous onset. All were stage I and all responded to HBO alone. This study shows that the incidence of ORN in Adelaide is low, probably through use of conservative doses of RT and good preventative protocols. The treatment with HBO plus or minus surgery was effective.