Medical treatment of osteoradionecrosis of the mandible by PENTOCLO: Preliminary results

Managing Mandibular Osteoradionecrosis

OBJECTIVE

Mandibular osteoradionecrosis (MORN) is a morbid complication of head and neck radiation therapy. Recent advances in surgical and medical therapies underscore the need for a shift in traditional treatment paradigms and a disease grading system that can guide appropriate management.

DATA SOURCES

Pubmed/MEDLINE.

REVIEW METHODS

We conducted a detailed review of publications related to MORN, specifically focusing on its staging and management techniques. Articles meeting inclusion criteria were synthesized into a final narrative review.

CONCLUSION

There has been a paradigm shift away from hyperbaric oxygen therapy in the management of MORN. Growing evidence for the efficacy of pentoxifylline and tocopherol in early-stage disease and novel surgical techniques to manage moderate and late-stage disease warrant an updated staging stratification which is proposed.

IMPLICATIONS FOR PRACTICE

This review summarizes the clinical efficacy of established and novel therapeutic modalities currently available in treating MORN, emphasizing the significant advances achieved over the last decade. It introduces a contemporary staging and treatment algorithm which incorporates traditional, evidence-supported surgical and medical management with effective early intervention strategies.

Is the use of Pentoxifylline and Tocopherol effective in the treatment of Osteoradionecrosis of the jaws or for the treatment of medicationosteonecrosis of the jaw? An overview

PURPOSE

The aim of the present study was to determine the methodological quality of systematic reviews that evaluated the effectiveness of pentoxifylline and tocopherol (PENTO) in the treatment of osteoradionecrosis of the jaw (ORNJ) and medication-related osteonecrosis of the jaw (MRONJ).

METHODS

Searches were performed in Databases including PubMed, Scopus, LILACS, DARE, Cochrane Library, and SIGLE through OpenGrey until March 2024, were evaluated by two independent reviewers to answer the following question: Is the use of PENTO protocol effective in the treatment of ORNJ or for the treatment of MRONJ?

RESULTS

A total of 256 articles were initially identified; however, following the use of appropriate inclusion and exclusion criteria, five systematic reviews were identified for detailed analysis. The final study sample comprised 588 patients: 397 patients with ORN and 197 patients with MRONJ who were treated with PENTO. The total recovery of individuals who used the PENTO protocol was 62,2 % for ORN and 100 % for MRONJ, with a follow-up period of 1 month to 10 years. The methodological quality of the studies was assessed using the AMSTAR 2 tool, in which four were of low quality and 1 moderate quality.

CONCLUSION

The treatment of ORN and MRONJ with pentoxifylline and tocopherol has shown good results in the studies presented, with a partial or total reduction in bone exposure. However, the low quality of the relevant reports highlights the need for primary and secondary studies with better methodological rigor to reduce bias and provide reassurance for this treatment option.

Denosumab-Induced Maxillary Osteonecrosis: A Case Study on Long-Term Complications in Multiple Myeloma Treatment

Background: Targeted therapies like denosumab have revolutionized multiple myeloma (MM) treatment, improved patient outcomes while introducing long-term complications. This study explores a rare instance of delayed maxillary osteonecrosis post-denosumab therapy, delving into its pathophysiology and management. Methods: A 40-year-old male MM patient who developed a painful palatal lesion post denosumab treatment and diagnosed of maxillary osteonecrosis by computed tomography scan and surgical biopsy is presented. Treatment history, symptom progression, and response to the PENTOCLO protocol were analyzed. Results: Post-denosumab discontinuation osteonecrosis highlights its prolonged impact on bone metabolism. PENTOCLO treatment protocol led to significant improvement. Genetic factors influencing osteonecrosis susceptibility have been discussed and considered. Conclusions: This case underscores the need for vigilance regarding long-term complications in MM survivors, preventive strategies, including regular dental evaluations and reducing invasive dental procedures, are crucial. We advocate for an interdisciplinary approach and further research into tailored prevention and management of osteonecrosis in cancer survivors.

Prevention and Management of Osteoradionecrosis in Patients With Head and Neck Cancer Treated With Radiation Therapy: ISOO-MASCC-ASCO Guideline

PURPOSE

To provide evidence-based recommendations for prevention and management of osteoradionecrosis (ORN) of the jaw secondary to head and neck radiation therapy in patients with cancer.

METHODS

The International Society of Oral Oncology-Multinational Association for Supportive Care in Cancer (ISOO-MASCC) and ASCO convened a multidisciplinary Expert Panel to evaluate the evidence and formulate recommendations. PubMed, EMBASE, and Cochrane Library databases were searched for randomized controlled trials and observational studies, published between January 1, 2009, and December 1, 2023. The guideline also incorporated systematic reviews conducted by ISOO-MASCC, which included studies published from January 1, 1990, through December 31, 2008.

RESULTS

A total of 1,539 publications were initially identified. There were 487 duplicate publications, resulting in 1,052 studies screened by abstract, 104 screened by full text, and 80 included for systematic review evaluation.

RECOMMENDATIONS

Due to limitations of available evidence, the guideline relied on informal consensus for some recommendations. Recommendations that were deemed evidence-based with strong evidence by the Expert Panel were those pertaining to best practices in prevention of ORN and surgical management. No recommendation was possible for the utilization of leukocyte- and platelet-rich fibrin or photobiomodulation for prevention of ORN. The use of hyperbaric oxygen in prevention and management of ORN remains largely unjustified, with limited evidence to support its practice.Additional information is available at www.asco.org/head-neck-cancer-guidelines.

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.

Prophylactic Use of Pentoxifylline and Tocopherol for Prevention of Osteoradionecrosis of the Jaw after Dental Extraction in Post-Radiated Oral and Oropharyngeal Cancer Patients: An Initial Case Series

Osteoradionecrosis of the jaw is a morbid complication of radiotherapy in patients with oral and oropharyngeal cancers that may be precipitated by dental extractions. Pentoxifylline and tocopherol (PENTO) has been utilized in the management of osteoradionecrosis and as prophylaxis for post-radiated head and neck oncology patients requiring an invasive dental procedure. This observational study aims to report the outcome of the prophylactic use of PENTO in the prevention of osteoradionecrosis of the jaw after dental extractions in post-radiated oral and oropharyngeal cancer patients and to review the current literature on this topic. Four post-radiated oral and oropharyngeal oncology patients were referred to the dental oncology clinic of the University Dental Practice, University of Tennessee Health Sciences Center for dental extractions. All four patients were prescribed pentoxifylline 400 mg BID (twice a day) and tocopherol 400 IU BID (oral tablets) for 2 weeks before extraction(s) and for 6 weeks after extraction(s). All patients were followed up every week after the second week post-extraction if feasible until the extraction site(s) healed (covered by mucosa). The assessment endpoint was defined as 6 weeks post-extraction with the outcomes assessed as using four categories determined by the area of exposed bone: complete healing (complete mucosal coverage of extraction site); partial healing (reduction in size of extraction site); no change; and progression (increase in size of the extraction site). At the assessment endpoint, all patients had complete healing of all extraction sites. The ORN rate at the patient level (0/4) and individual tooth level (0/8) was 0%. All patients tolerated the PENTO medications and no adverse effects from the use of these medications were reported. This limited study in addition to the other reviewed studies estimates the rate of ORN at the patient level as 3.2% (14/436) for post-radiated head and neck oncology patients after dental extractions/invasive oral procedures. In conclusion, this PENTO regimen can reduce/prevent the incidence of ORN in post-radiated head and neck oncology patients. This safe and cost-effective protocol (PENTO regimen) should be further evaluated as prophylaxis for post-radiated head and neck oncology patients requiring an invasive dental procedure. We recommend large prospective studies to be carried out to further validate these findings.

Medication-related osteonecrosis of the jaw: evolving research for multimodality medical management

PURPOSE

Medication-related osteonecrosis of the jaw (MRONJ) is a debilitating side effect of antiresorptive and antiangiogenic agents that can lead to progressive bone destruction in the maxillofacial region. Dental surgery, including tooth extractions, commonly trigger the onset of MRONJ. While guidelines suggest avoiding extraction when possible, complete avoidance is not always feasible, as necrosis can develop from dental and periodontal disease without dental procedures. The goal of this article is to provide an update review of current preventive and therapeutic approaches for MRONJ.

METHODS

A comprehensive electronic search was conducted on PubMed/MEDLINE, Embase, and Scopus databases. All English articles encompassing randomized controlled trials, systematic reviews, observational studies, and case studies were reviewed. The current medical treatments and adjuvant therapies for managing MRONJ patients were critically assessed and summarized.

RESULTS

Pentoxifylline and alpha tocopherol (PENT-E), teriparatide, photobiomodulation (PBM), photodynamic therapy (PDT), and the use of growth factors have shown to enhance healing in MRONJ patients. Implementing these methods alone or in conjunction with surgical treatment has been linked to reduced discomfort and improved wound healing and increased new bone formation.

DISCUSSION

While several adjuvant treatment modalities exhibit promising results in facilitating the healing process, current clinical practice guidelines predominantly recommend antibiotic therapy as a non-surgical approach, primarily addressing secondary infections in necrotic areas. However, this mainly addresses the potential infectious complication of MRONJ. Medical approaches including PENT-E, teriparatide, PBM, and PDT can result in successful management and should be considered prior to taking a surgical approach. Combined medical management for both preventing and managing MRONJ holds potential for achieving optimal clinical outcomes and avoiding surgical intervention, requiring further validation through larger studies and controlled trials.

Mandibular Osteoradionecrosis: Defining the Microbial Milieu and Antimicrobial Resistance at the Time of Rescue Flap Surgery

OBJECTIVE

To report the microorganisms and their antibiotic sensitivity profile from tissue cultures and stains at the time of anterolateral thigh fascia lata (ALTFL) rescue flap for management of mandibular osteoradionecrosis (ORN).

METHODS

Retrospective chart review of patients who underwent ALTFL rescue flap for native mandibular ORN between 2011 and 2022.

RESULTS

Twenty-six cases comprising 24 patients (mean age 65.4 years, 65.4% male) with mandibular ORN from whom tissue cultures and gram stain were obtained at the time of ALTFL rescue flap. 57.7% grew bacterial species, while 34.6% grew fungal species. Multibacterial speciation was noted in 26.9% of cultures. A combination of bacterial and fungal growth was also seen in 15.4% of cases. All gram-positive cocci (GPC) were pansensitive to antibiotics except for one case of Staphylococcus aureus, which was resistant to levofloxacin. Gram-negative bacilli (GNB) species were isolated in 50.0% of cases. All fungal growth was due to Candida species. No growth was noted in 23.1% of cases. Multidrug resistance was noted in 53.8% of cases when GNB was isolated.

CONCLUSION

We report 76.9% of our cases of mandibular ORN had microbial growth from tissue cultures obtained at the time of the ALTFL rescue flap. Fungal growth was noted in a substantial number of cases and should be obtained as a specimen when pursuing culture-driven antibiotic therapy. Most GPCs were pansensitive to antibiotics, while GNBs were often the harbinger of multidrug resistant mandibular ORN.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:166-169, 2024.

Medication-related osteonecrosis in torus palatinus: Report of a case and literature review

BACKGROUND

Medication-related osteonecrosis of the jaw bones have been frequently reported. However, its occurrence in torus palatinus is very rare with only 10 cases published in the English-language literature.

CASE REPORT

We describe an additional case in a 79-year-old woman, who was referred for evaluation of a painful swelling with areas of suppuration on the hard palate.

CONCLUSION

Conservative treatment was performed and after spontaneous sequestrectomy, total healing was achieved.

The use of liquid formulation pentoxifylline and vitamin E in both established and as a prophylaxis for dental extractions "at risk" of osteoradionecrosis

BACKGROUND

Osteoradionecrosis (ORN) of the jaws remains one of the most debilitating complications of radiotherapy (RT) in patients with head and neck cancer (HNC). Liquid pentoxifylline and vitamin E (PVe) presents an alternative formulation to tablets for patients with dysphagia or enteric feeding.

OBJECTIVE

This study aimed to assess the clinical outcomes of using a liquid formulation of PVe for both established ORN and as a prophylaxis to avoid its occurrence after dental extractions. A secondary objective was to determine patient-reported side effects in relation to the liquid formulation of PVe.

STUDY DESIGN

The clinical records of 111 patients with HNC who were prescribed liquid PVe were reviewed retrospectively (66 with established ORN and 45 as prophylaxis before an invasive dental procedure).

RESULTS

In established ORN, 44% healed, and 41% were stable. In the prophylaxis group, 96% of surgical sites healed completely, with 4% (n = 2) developing ORN. Most patients (89%) were able to tolerate liquid PVe. Of the 11% (n = 12) who could not tolerate this regime, the most commonly reported side effect was gastric irritation (n = 5/12), whereas no more than 1 patient reported dizziness, malaise, and bleeding.

CONCLUSIONS

This retrospective review suggests that liquid PVe is efficacious for both established ORN and as a prophylaxis. Side effects reported were similar to those recognized for the tablet formulation.

Evaluation of Anterolateral Thigh Fascia Lata Rescue Flap for Mandibular Osteoradionecrosis

Importance

Mandibular osteoradionecrosis (ORN) is a progressive disease that can be difficult to treat. Conservative measures often fail, while conventional definitive management requires a morbid segmental resection with osteocutaneous reconstruction. Evidence of the anterolateral thigh fascia lata (ALTFL) rescue flap technique's safety, effectiveness, and long-term outcomes is needed.

Objective

To determine the long-term outcomes of the ALTFL rescue flap procedure for treating patients with mandibular ORN.

Design, Settings, and Participants

This was a retrospective medical record review performed at a single tertiary-level academic health care institution with patients who were appropriate candidates for the ALTFL procedure to treat mandibular ORN from March 3, 2011, to December 31, 2022. Data analyses were performed from January 1 to March 26, 2023.

Main Outcomes and Measures

Patient characteristics, preoperative radiographic Notani staging, intraoperative defect size, length of stay, complication rates, and clinical and radiographic findings of progression-free intervals.

Results

The study population of 43 patients (mean [SD] age, 66.1 [47-80] years; 24 [55.8%] male individuals) included 52 cases of mandibular ORN. The preoperative Notani staging of the study population was known for 46 of the 52 total cases: 11 cases (23.9%) were stage I; 21 (45.7%), stage II; and 14 (30.4%), stage III. The mean defect area was 20.9 cm2. Successful arrest of ORN disease progression was noted in the clinical and radiographic findings of 50 of the 52 (96.2%) cases, with only 2 (3.8%) cases subsequently requiring fibular free flap reconstruction. The major complication rate was 1.9% (1 case). Clinical and radiographic progression-free intervals were assessed, and no statistically significant differences were noted between Notani staging groups (log-rank P = .43 and P = .43, respectively); ie, patients with stage III disease had no significant difference in risk of clinical (HR, 0.866; 95% CI, 0.054-13.853) or radiographic (HR, 0.959; 95% CI, 0.059-15.474) progression vs those with stage I disease. Weibull profiling revealed 96.9%, 94.6%, and 93.1% successful mandibular ORN arrest at 1, 3, and 5 years, respectively. The major complication rate was 1.9%. Mean (SD) length of stay was 2.7 (0.0-7.0) days. Mean (SD) radiographic follow-up was 29.3 (30.7) months.

Conclusions and Relevance

The findings of this large retrospective patient case series support the continued success of the ALTFL rescue flap technique, a safe and highly effective long-term treatment for mandibular ORN in carefully selected patients.

Treating radiation‑related nasopharyngeal necrosis with endostar in patient with nasopharyngeal carcinoma: A report of two cases and a literature review

Radiation-related nasopharyngeal necrosis (RRNN) is a rare and often fatal complication in patients with nasopharyngeal carcinoma (NPC). Currently, no standard treatments are recommended for RRNN. The effects of traditional conservative treatments are suboptimal, and surgery for RRNN cannot be performed by inexperienced doctors. In the present study, the use of Endostar in two patients with RRNN was evaluated. Two patients with RRNN were treated at the Department of Oncology, Panyu Central Hospital (Guangzhou, China). Endostar was administrated (15 mg/day from day 1 to day 7, every three weeks) intravenously for four and seven cycles in a male and a female patient, respectively. The effects of Endostar were assessed using magnetic resonance imaging (MRI) and a nasopharyngoscope. The symptoms of RRNN in both patients were relieved after treatment with Endostar. MRI and nasopharyngoscope analysis revealed that necrosis of the nasopharynx was substantially decreased and nasopharyngeal ulcers were healed. Endostar has the potential to be a novel, effective therapy for the treatment of patients with RRNN. However, clinical trials are required to confirm the results of the present study.

Free Tissue Transfer for Skull Base Osteoradionecrosis: A Novel Approach in the Endoscopic Era

OBJECTIVES

Osteoradionecrosis (ORN) of the skull base and craniovertebral junction is a challenging complication of radiation therapy (RT). Severe cases often require surgical intervention through a multi-modal approach. With the evolution in endoscopic surgery and advances in skull base reconstruction, there is an increasing role for microvascular free tissue transfer (MFTT). We describe an endoscopic-assisted approach for the management of ORN of the skull base using fascia lata for MFTT.

STUDY DESIGN

Retrospective case series.

METHODS

Between 2017 and 2021, a review of all cases in which fascia lata MFTT was utilized for skull base ORN was performed. Patient demographics, preoperative characteristics, and postoperative outcomes with long-term follow-up were reviewed.

RESULTS

Five patients were identified. Mean duration to onset of ORN was 17 months following RT. A trial of antibiotics, hyperbaric oxygen (HBO), and/or limited debridement was attempted without success. Refractory pain and progressive osteomyelitis were unifying symptoms. All patients underwent endoscopic debridement of the affected region of ORN prior to MFTT. Vascularized fascia lata was inset through a combined endonasal and transoral corridor. There was improvement in chronic pain in the postop setting with no patients requiring continued antibiotics or HBO therapy. Mean post-op follow-up was 23 months.

CONCLUSIONS

With continued evolution in endoscopic, minimally invasive approaches, there is an expanding indication for early surgical management in refractory ORN. Fascia lata MFTT is a novel and effective strategy for the management of ORN of the skull base and upper cervical spine with excellent postoperative outcomes and limited patient morbidity.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:562-568, 2023.

Immune microenvironment: novel perspectives on bone regeneration disorder in osteoradionecrosis of the jaws

Osteoradionecrosis of the jaws (ORNJ) is a severe complication that occurs after radiotherapy of head and neck malignancies. Clinically, conservative treatments and surgeries for ORNJ exhibited certain therapeutic effects, whereas the regenerative disorder of the post-radiation jaw remains a pending problem to be solved. In recent years, the recognition of the role of the immune microenvironment has led to a shift from an osteoblasts (OBs) or bone marrow mesenchymal stromal cells (BMSCs)-centered view of bone regeneration to the concept of a complicated microecosystem that supports bone regeneration. Current advances in osteoimmunology have uncovered novel targets within the immune microenvironment to help improve various regeneration therapies, notably therapies potentiating the interaction between BMSCs and immune cells. However, these researches lack a thorough understanding of the immune microenvironment and the interaction network of immune cells in the course of bone regeneration, especially for the post-operative defect of ORNJ. This review summarized the composition of the immune microenvironment during bone regeneration, how the immune microenvironment interacts with the skeletal system, and discussed existing and potential strategies aimed at targeting cellular and molecular immune microenvironment components.

18F-FDG PET/CT for early response assessment of jaw osteoradionecrosis after the PENTOCLO protocol: A promising imaging modality

INTRODUCTION

The Pentoxifylline, Tocopherol and Clodronate protocol (PENTOCLO) showed promising results for jaw osteoradionecrosis (ORN) management. However, the clinical and radiological improvements are often delayed, leading to unwanted long-term treatment, with potential loss of opportunity for more radical surgical treatments. Our objective was to assess the diagnosis performance of ¹⁸F-FDG PET/CT to early predict ORN response to the PENTOCLO protocol.

MATERIALS AND METHODS

All patients from our center who were treated with the PENTOCLO protocol and with a ¹⁸F-FDG PET/CT performed at diagnosis and three months after the end of antibiotherapy were retrospectively included. The PENTOCLO protocol was always combined with prior appropriate antibiotherapy for six weeks. The healing endpoint was divided into healing, stability or worsening, according to the combination of clinical and radiological assessments at the date of last follow-up. For each patient, the difference between the maximal standardized uptake value (ΔSUVmax) of the ORN lesion at three months and baseline were computed. Diagnostic performance of ¹⁸F-FDG PET/CT was evaluated by sensitivity, specificity and the area under the receiver operating characteristic curve (ROC-AUC) of ΔSUVmax.

RESULTS

24 patients were included with an average follow-up of 29.3 months. The healing, stability and worsening rate were 25%, 62.5% and 12.5% respectively. The AUC for discriminating worsening vs stability or healing was 0.92 (IC95 [0.81-1.00]). A ΔSUVmax greater than or equal to 0 was predictive of a worsening with a sensitivity and specificity of 84 and 66% respectively.

CONCLUSION

¹⁸F-FDG PET/CT imaging could be useful for early prediction of PENTOCLO treatment resistance with appropriate antibiotherapy.

Aggressive Treatment Including Endonasal Surgical Sequestrectomy with Vascularized Nasoseptal Flap Can Improve Outcomes of Skull Base Osteoradionecrosis

Objective  Skull base osteoradionecrosis (SB-ORN) is a serious, potentially lethal complication of radiation therapy. We aimed to review the clinical characteristics and outcomes of SB-ORN according to the extent of treatment. Design  Retrospective analysis design was used for this study. Setting  The study was conducted in two tertiary care hospitals. Participants  Patients included who had been clinically diagnosed with SB-ORN from January 2006 to 2017. Main Outcome Measures  Clinical characteristics, including demographics, predisposing factors, presenting symptoms, radiological findings, treatment modalities, and treatment outcomes, were reviewed. Treatment was classified into conservative and aggressive types. Aggressive treatment included radical surgical removal of soft tissue and bony sequestrum with the placement of vascularized tissue. Treatment outcome was analyzed in terms of clinical control, survival, and carotid artery blow out. Results  Fifteen patients (11 males and 4 females) were identified during the study period. Eight patients were managed conservatively, whereas seven patients were managed with aggressive treatment. The 2-year survival was 75% in the aggressive treatment group and 15% in the conservative group (log-rank, p  = 0.049). The estimated 2-year blow out free rate was 46.7% for the conservative group and 100% for the aggressive group (log-rank, p  = 0.100). Conclusion  In patients with SB-ORN, aggressive management, including surgical removal of sequestrum and coverage with a pedicled flap, is associated with increased survival.

Pentoxifylline and tocopherol (vitamin E) with/without clodronate for the management of osteoradionecrosis: A scoping review

BACKGROUND

Treatment of osteoradionecrosis (ORN) is not a straightforward task, and it is unpredictable. However, a combination of pentoxifylline; an antioxidant drug, and tocopherol (vitamin E) works as a potent antifibrotic agent and have shown recently both significant and impressive results.

AIMS

This scoping review aims to investigate the most prescribed regimen of pentoxifylline and tocopherol with/without clodronate for the management of ORN.

METHODS

Ovid MEDLINE and EMBASE databases were used to retrieve eligible studies using planned search keywords. PROSPERO and Cohcarne library were also searched for ongoing or published systematic reviews, respectively. Included articles were grouped thematically according to the type of studies and accordingly they were summarized.

RESULTS

A total of 27 articles met the inclusion criteria and included in the data analyses. All the included articles were published between 1997 and 2020. Of these 27 included studies, two were randomized control trials, two were systematic reviews, six were retrospective studies, five were observational studies, seven were narrative reviews, four were case reports, and lastly one was an in-vitro study.

CONCLUSIONS

Treatment by PENTO (800 mg of pentoxifylline + 1000 IU of tocopherol) once daily for an early established ORN or PENTOCLO (PENTO regimen + 1600 mg of clodronate) once daily for the refractory/severe cases of ORN appears to be the most prescribed regimen used for the treatment of ORN using these drugs. These drugs appear safe, effective and inexpensive for the treatment of ORN.

Prophylactic pentoxifylline and vitamin E use for dental extractions in irradiated patients with head and neck cancer

OBJECTIVE

Osteoradionecrosis (ORN) of the jaw is preceded by dental extractions in up to 10% of cases. We present a case series of post-radiotherapy patients undergoing dental extractions who have received the prophylactic antifibrotic agents pentoxifylline and vitamin E (PVe) to prevent ORN.

STUDY DESIGN

A retrospective review was conducted of 219 patients with head and neck cancer (HNC) undergoing 1079 dental extractions between 2009 and 2020. Data regarding oncological treatment, prophylactic drug regimen, dental history, and clinical outcome was collected.

RESULTS

Twelve patients developed ORN at 17 extraction sites (ORN rates, 1.6% and 5.5% at tooth level and patient level, respectively). PVe regimen compliance significantly decreased ORN rates at the patient level (3.4% vs 11.5%; P < .03) and the tooth level (1.0% vs 3.5%; P < .01) compared with no PVe. Regimen compliance significantly reduced ORN rates in patients with oropharyngeal cancer (P < .01); in those with mandibular (P < .005) molar (P < .003), and flapless extractions (P < .04); in patients with radiation regions >40 Gy (P < .0009); and in those who underwent primary closure (P < .03). Machine learning analysis identified almost all these factors as influential at a tooth level for ORN.

CONCLUSIONS

PVe regimen compliance decreased dental extraction ORN rates more than the literature base rates of 7% at the patient level and 2% at the tooth level. Given its success in managing existing ORN, PVe could be extended prophylactically for dental extractions in irradiated patients with head and neck cancer.

Platelet-rich fibrin as a treatment option for osteoradionecrosis: A literature review

The aim of this review is to establish the usefulness and effectiveness of using platelet-rich fibrin (PRF) in the treatment of osteoradionecrosis (ORN) lesions. A review of the literature was performed using keywords through the PubMed-Medline and Cochrane Library search engine. Inclusion criteria were: (1) original publication in either the French or the English language, (2) studies conducted in humans, (3) presence of ORN lesions following head and neck radiotherapy (RT), (4) use of PRF or derivates in the treatment of ORN lesions, (5) clinical variables and outcomes mentioned in the study. Overall, four case reports were retained. Two publications were removed from the initial seven results after application of the inclusion criteria. A recent randomised clinical trial was not considered since the group analysed the effectiveness of leukocyte-enriched Plasmas-Rich-Fibrin (LPRF) in preventing ORN, but not in treating it. Therefore, four publications were retained for analysis. Results suggest that using PRF as an adjunct to surgical therapy is beneficial in treating ORN lesions although no controlled studies were found. Therefore, additional controlled clinical studies are warranted to better define the effectiveness and recommendation of this approach.

Surgical Management of Skull Base Osteoradionecrosis in the Cancer Population - Treatment Outcomes and Predictors of Recurrence: A Case Series

BACKGROUND

Skull base osteoradionecrosis (ORN) is a challenging treatment-related complication sometimes seen in patients with cancer. Although ORN management strategies for other anatomic sites have been reported, there is a paucity of data guiding the management of skull base ORN.

OBJECTIVE

To report a single-center tertiary care series of skull base ORN and to better understand the factors affecting ORN recurrence after surgical management.

METHODS

We conducted a retrospective cohort study of patients with skull base ORN treated at our center between 2003 and 2017. Univariate and multivariate binary logistic regressions were performed to identify predictors of recurrence.

RESULTS

A total of 31 patients were included in this study. The median age at ORN diagnosis was 61.1 yr (range, 32.8-84.9 yr). Of these 31 patients, 15 (48.4%) patients were initially treated medically. All 31 patients underwent surgery. Three (14.3%) of 21 patients treated with a free flap and 4 (50.0%) of 8 patients who underwent primary closure experienced recurrence. Cox regression analysis revealed that reconstruction with local tissue closure (P = .044) and ongoing treatment for active primary cancer (P = .022) were significant predictors of recurrence. The median overall survival from index surgery for ORN treatment was 83.9 mo. At 12-mo follow-up, 78.5% of patients were alive.

CONCLUSION

In this study, we assess the outcomes of our treatment approach, surgical debridement with vascularized reconstruction, on recurrence-free survival in patients with skull base ORN. Further studies with larger cohorts are needed to assess current treatment paradigms.

Postradiation Fractures after Combined Modality Treatment in Extremity Soft Tissue Sarcomas

Soft tissue sarcoma (STS) of the extremities is typically treated with limb-sparing surgery and radiation therapy; with this treatment approach, high local control rates can be achieved. However, postradiation bone fractures, fractures occurring in the prior radiation field with minimal or no trauma, are a serious late complication that occurs in 2–22% of patients who receive surgery and radiation for STS. Multiple risk factors for sustaining a postradiation fracture exist, including high radiation dose, female sex, periosteal stripping, older age, femur location, and chemotherapy administration. The treatment of these pathological fractures can be difficult, with complications including delayed union, nonunion, and infection posing particular challenges. Here, we review the mechanisms, risk factors, and treatment challenges associated with postradiation fractures in STS patients.

The use of pentoxifylline, tocopherol and clodronate in the management of osteoradionecrosis of the jaws

AIMS

Medical management of osteoradionecrosis (ORN) via pentoxifylline, tocopherol (PENTO) and clodronate (PENTOCLO) has shown both promise and early positive outcomes. We aimed to determine clinical outcomes for patients with established ORN managed solely via PENTO or PENTOCLO.

METHODS

The study retrospectively reviewed and collected data from the medical records of 169 patients diagnosed with ORN and treated via medical management. Patients that received any additional interventions such as surgery or hyperbaric oxygen were not included.

RESULTS

Medical management led to healed ORN in 54.4% (n = 92/169) of patients after an average of 12.9 months. Outcome comparison between PENTO and PENTOCLO identified the former regime to be significantly superior (p = 0.0001). There is an inverse relationship with increasing ORN severity and healing with medical management (p < 0.0001) with oropharyngeal cancer (p = 0.0347) patients responding favourably via this approach. Infection had a critical role in the final outcome with those healing requiring 1.3 antibiotic prescriptions, while those that had disease progression requiring 4.3 prescriptions.

CONCLUSION

Medical management is a viable treatment option for ORN. It appears to be most effective in Notani I and non-infected ORN. When healing was not achieved the regime was able to stabilise the condition.

Fasciocutaneous Flaps for Refractory Intermediate Stage Osteoradionecrosis of the Mandible-Is It Time for a Shift in Management?

PURPOSE

Historically, free tissue transfer has been reserved for advanced stage osteoradionecrosis (ORN) of the jaw with pathologic fracture or cutaneous fistula. The purpose of this study was to evaluate if in patients with recalcitrant intermediate stage ORN, would mandibular debridement in combination with vascularized soft tissue coverage result in durable symptom and disease resolution.

PATIENTS AND METHODS

A retrospective cohort study of patients with mandibular ORN was performed comparing a mandibular preserving approach with a fasciocutaneous forearm flap for progressive treatment-resistant intermediate stage ORN to mandibulectomy and vascularized bone flap (VBF) reconstruction for advanced stage ORN. The primary outcome was ORN resolution.

RESULTS

The sample was composed of 35 patients. One-hundred percent of patients undergoing a mandibular preserving approach experienced ORN resolution compared with 83.3% in the segmental mandibulectomy and VBF reconstruction group (P = .28). Patients in the mandibular preservation group experienced a shorter hospitalization (6 vs 9 days; P = .07), decreased length of surgery (384.9 vs 406.3 minutes; P = .01), and less delayed healing requiring local wound care (9.1 vs 45.8% of patients; P = .06).

CONCLUSIONS

A mandibular preserving approach is successful at arresting intermediate stage ORN and is associated with a decreased operative time, a shorter hospitalization, and less need for prolonged wound care when compared with VBF reconstruction for advanced stage ORN.

Preoperative status and treatment of osteoradionecrosis of the jaw: a retrospective study of 252 cases

Osteoradionecrosis of the jaw (ORNJ) is one of the most devastating and progressive complications of head and neck radiotherapy. It can cause emaciation, deformity, and pathological fractures, resulting in decreased quality of life. The aim of this study was to evaluate the preoperative index and outcomes of treatment for ORNJ. A retrospective study of 252 ORNJ cases treated at one institution between January 2010 and January 2018 was made. The abnormal items from the preoperative examination and follow-up after different treatments were recorded, and the differences between the noteworthy items were compared using univariate and multivariate models. Most ORNJ patients in the middle and late stages had abnormal items, such as hypoproteinaemia, anaemia, and leucocytosis. Partial mandibulectomy with flap reconstruction was significantly more effective than without reconstruction. Advanced ORNJ patients tended to have more abnormal items, which might have a negative influence on treatment. For better outcomes, it is essential and effective to completely remove the necrotic lesion and reconstruct it with a flap. The surgeons should provide sufficient perioperative management and strive for suitable surgical treatment.

Does hyperbaric oxygen therapy play a role in the management of osteoradionecrosis? A survey of Dutch oral and maxillofacial surgeons

For decades, hyperbaric oxygen (HBO) has often been part of the treatment of osteoradionecrosis (ORN), despite controversy in the literature about its efficacy. An online survey was conducted to investigate the use of HBO in the treatment of ORN by Dutch oral and maxillofacial surgeons and to assess their perception of its efficacy. Of the 53 Dutch oral and maxillofacial surgery units contacted, 49 (92%) replied. Thirty-five were not head and neck cancer (HNC) units or preferred partner (PP-HNC) units recognized by the Dutch Head and Neck Association. All HNC and PP-HNC units (group 1) treated ORN patients, compared to only 12 (34%) of the non-HNC units (group 2). The average number of ORN patients seen and treated was higher in group 1. The units in group 1 more often referred patients for HBO therapy (HBOT) than those in group 2 (93% vs 84%). The efficacy of HBOT in curing ORN, rated on a scale of 1 to 5 points, was 3.7 in group 1 and 3.2 in group 2. This survey shows a trend towards centralization of ORN care to more experienced units. These units tend to use HBOT in curing ORN.

External fixation greatly improves outcomes in the surgical treatment of osteoradionecrosis of the jaws without affecting quality of life: a five-year retrospective study

Osteoradionecrosis of the jaw can be treated using both conservative treatment and surgery. External fixation may be used to bridge large resection defects after sequestrectomy for stabilisation and before secondary mandibular reconstruction. We designed a retrospective analysis of 70 patients with osteoradionecrosis treated between the years 2014 and 2018, and found that the use of external fixation greatly improves their outcomes. Patients were grouped according to Notani's classification: those who had Notani I disease were treated surgically but without external fixation; and those with Notani II and Notani III disease were eligible for external fixation. In those with Notani II disease, there was a significant reduction in the number of pathological fractures that occurred with external fixation. In those with Notani III disease, the success rate of primary sequestrectomy was only 1:14; however, those treated with external fixation all successfully healed after their first operation. It was hypothesised that although external fixation would improve outcome, it would come at a detriment to their quality of life (QoL). However, in a subset of these patients, we showed that in addition to increasing successful healing, patients' QoL with the external fixator was no worse than when they had an active osteonecrotic lesion. The treatment of osteoradionecrosis is cumbersome and advanced stages are associated with more complications. The use of an external fixator significantly reduces the probability of pathological fractures and increases the rate of successful healing in patients after mandibular resection. It does this without greatly interfering with patients' lives, while improving their condition sufficiently to allow for subsequent mandibular reconstruction.

Chinese expert group consensus on diagnosis and clinical management of osteoradionecrosis of the mandible

Osteoradionecrosis of the mandible (MORN) is one of the most devastating complications caused by radiation therapy in the head and neck region. It is characterized by infection and chronic necrosis of the mandible as the main manifestation. Clinically, MORN-related symptoms include swelling, pain, dysphagia, trismus, masticatory or speech disorders, refractory orocutaneous fistula, bone exposure, and even pathological fracture. MORN has become a challenging clinical problem for oral and maxillofacial surgeons to deal with, but thus far, this problem has not been solved due to the lack of widely accepted treatment algorithms or guidelines. Because of the nonexistence of standardized treatment criteria, most clinical treatment against MORN nowadays is largely based on controversial empirical understandings, while recommendations on post-therapeutic evaluations are scarce. Therefore, to further unify and standardize the diagnosis and treatment of MORN, to decrease the huge waste of medical resources, and ultimately, to improve the wellbeing of the patients, the Chinese Society of Oral and Maxillofacial Surgery (CSOMS) convened an expert panel specialized in MORN from 16 domestic medical colleges and affiliated hospitals to discuss the spectrum of diagnosis and and formulate treatment. In addition, consensus recommendations were also revised with a comprehensive literature review of the previous treatment experiences and research pearls. This 'expert consensus statement on diagnosis and clinical management of MORN' is for clinical reference.

Research Frontiers in Oral Toxicities of Cancer Therapies: Osteoradionecrosis of the Jaws

The deleterious effects of head and neck radiation on bone, with osteoradionecrosis (ORN) as the major disabling side effect of head and neck cancer treatment, are difficult to prevent and hard to treat. This review focuses on the current state of the science regarding the pathobiology, clinical impact, and management of ORN. With regard to the pathobiology underlying ORN, it is not yet confirmed whether the current radiation schedules by 3-dimensional conformal radiotherapy and intensity modified radiotherapy result in an unchanged, decreased, or increased risk of developing ORN when compared with conventional radiation treatment, the main risk factor being the total radiation dose delivered on any clinically significant surface of the mandible.

With regard to the prevention of ORN, a thorough, early pre-irradiation dental assessment is still considered the first step to reduce the hazard of developing ORN post-radiotherapy, and hyperbaric oxygen (HBO) treatment reduces the risk of developing ORN in case of dental surgery in an irradiated field.

With regard to the treatment of ORN, the focus is bidirectional: elimination of the necrotic bone and improving the vascularity of the normal tissues that were included in the radiation portal. The cure rate of limited ORN by conservative therapy is approximately 50%, and the cure rate of surgical approaches when conservative therapy has failed is approximately 40%.

Whether it is effective to support conservative or surgical treatment with HBO as an adjuvant is not set. HBO treatment is shown to increase the vascularity of hard and soft tissues and has been reported to be beneficial in selected cases. However, in randomized clinical trials comparing the preventive effect of HBO on developing ORN with, eg, antibiotic coverage in patients needing dental surgery, the preventive effect of HBO was not shown to surpass that of a more conservative approach.

More recently, pharmacologic management was introduced in the treatment of ORN with success, but its efficacy has to be confirmed in randomized clinical trials. The major problem of performing well-designed randomized clinical trials in ORN is having access to large numbers of patients with well-defined, comparable cases of ORN. Because many institutions will not have large numbers of such ORN cases, national and international scientific societies must be approached to join multicenter trials. Fortunately, the interest of funding organizations and the number researchers with an interest in healthy aging is growing. Research aimed at prevention and reduction of the morbidity of cancer treatment fits well within these programs.

Protocol for prospective randomised assessor-blinded pilot study comparing hyperbaric oxygen therapy with PENtoxifylline+TOcopherol± CLOdronate for the management of early osteoradionecrosis of the mandible

INTRODUCTION

Osteoradionecrosis (ORN) of the mandible is a painful and debilitating condition occurring after radiotherapy to the head and neck to treat cancer. For decades, hyperbaric oxygen (HBO) has formed the mainstay of the early management of ORN. Literature about the efficacy of HBO is contentious. Recently, Oral and Maxillofacial surgical units in France and UK have trialled a combination of medications to treat ORN, also known as PENTOCLO (PENtoxifylline+TOcopherol±CLOdronate). This regime has shown promising results to date however randomised controlled trials in the area comparing HBO against PENTOCLO are lacking and there are no current trials registered in Europe, UK, Australia and the USA. The purpose of this pilot study is to generate a hypothesis that can be tested in large multi-centre controlled trials.

METHODS AND ANALYSIS

For this pilot study we will recruit 16 patients who will be randomly allocated to one of either HBO or PENTOCLO. After a 4 week period of uniform 'pre-treatment' medication patients will be commenced on their allocated treatment. Standard follow-up examination, imaging and photographs will be taken and de-identified and then presented to two Oral and Maxillofacial surgeons for allocation of a Notani & Lyons classification score. Data for each patient will be tracked over the 18 months of treatment and follow-up. The results will then be analysed using descriptive statistics and all patients included in an intention to treat analysis.

ETHICS AND DISSEMINATION

Ethical approval for this study has been granted by the South Metropolitan Health Service HREC (PRN RGS0000001193). Data generated by conducting this study will be uploaded to an open access repository in a de-identified form. Results from this study will be disseminated at national and international conferences as well as peer reviewed medical publications.

TRIAL REGISTRATION NUMBER

ACTRN12618001099213; Pre-results.

Heparan Sulfate Mimetics: A New Way to Optimize Therapeutic Effects of Hydrogel-Embedded Mesenchymal Stromal Cells in Colonic Radiation-Induced Damage

Clinical expression of gastrointestinal radiation toxicity on non-cancerous tissue could be very life threatening and clinicians must deal increasingly with the management of late side effects of radiotherapy. Cell therapy, in particular mesenchymal stromal cell (MSC) therapy, has shown promising results in numerous preclinical animal studies and thus has emerged as a new hope for patient refractory to current treatments. However, many stem cell clinical trials do not confer any beneficial effect suggesting a real need to accelerate research towards the successful clinical application of stem cell therapy. In this study, we propose a new concept to improve the procedure of MSC-based treatment for greater efficacy and clinical translatability. We demonstrated that heparan sulfate mimetic (HS-m) injections that restore the extracellular matrix network and enhance the biological activity of growth factors, associated with local injection of MSC protected in a hydrogel, that increase cell engraftment and cell survival, improve the therapeutic benefit of MSC treatment in two animal models relevant of the human pathology. For the first time, a decrease of the injury score in the ulcerated area was observed with this combined treatment. We also demonstrated that the combined treatment favored the epithelial regenerative process. In this study, we identified a new way, clinically applicable, to optimize stem-cell therapy and could be proposed to patients suffering from severe colonic defect after radiotherapy.

Protective role of α2-macroglobulin against jaw osteoradionecrosis in a preclinical rat model

OBJECTIVE

We have previously demonstrated the effect of alpha-2-macroglobulin (α2M) in the remediation of radiation-induced cellular damage. Here, we investigated the protective effects of α2M in a preclinical rat model of jaw osteoradionecrosis (ORN).

METHODS

Eighteen rats were divided randomly into three groups: the control group, the radiation therapy (RT) alone group, and the radiated mandibles pretreated with α2M (α2M + RT) group. One month after radiation, all left molar teeth were extracted. After another 3 months, the animals were sacrificed and body weight, histopathology, microcomputed tomography and immunofluorescence were evaluated in all groups.

RESULTS

The RT group showed serious alopecia, bone exposure, inflammation, necrosis, fibrosis, and the absence of new bone formation within the socket. The α2M + RT group exhibited less alopecia than the RT group and slight inflammation and fibrosis in the bone marrow cavity. The cortical bone was similar to normal bone tissue. Interestingly, compared with RT group, serum superoxide dismutase levels in the α2M + RT group increased at the 1th day (P = 0.037), 14th day (P = 0.012), while reactive oxygen species levels clearly decreased at the 1th day (P< 0.001), 14th day (P = 0.007), and 28th day (P = 0.013).

CONCLUSIONS

A clinically translational model of jaw ORN was successfully established and the application of α2M prior to radiation protected the bone from being injured by the radiation, possibly related to oxidative stress.

Management of incidental discovery of microscopic squamous cell carcinoma in zones of osteoradionecrosis of the mandible

OBJECTIVES

Osteoradionecrosis (ORN) of the mandible is a common complication of head and neck radiotherapy and often requires surgical treatment. Squamous cell carcinoma (SCC) can be exceptionally discovered within zones of ORN on histological examination of the operative specimen. The authors discuss the management of these lesions based on a short patient series.

MATERIALS AND METHODS

This single-centre retrospective study was based on patients managed between 2012 and 2014 for ORN with incidental discovery of microscopic SCC.

RESULTS

Five patients with incidental discovery of microscopic SCC in a zone of ORN of the mandible were included in this study. The mean time to onset of ORN after the end of radiotherapy for locally advanced SCC of the oral cavity or oropharynx was 42 months. Surgical treatment consisted of marginal or segmental mandibulectomy with free flap reconstruction. No recurrence was observed with a mean follow-up of 35 months [24-46].

CONCLUSION

The incidental discovery of microscopic SCC in a zone of ORN of the mandible is a rare event and has not been reported in the literature. Optimal management cannot be reliably defined due to the lack of data in the literature, but the present study supports careful histological examination of ORN specimens. Treatment must be as conservative as possible to avoid excessively invasive surgery.

Successful treatment of grade III osteoradionecrosis with mandibular fracture with pentoxifylline, tocopherol and clodronate

Osteoradionecrosis (ORN) is one of the most severe complications after head and neck radiotherapy. Once established, ORN is difficult to manage and is traditionally considered to be irreversible. Since the recent understanding of the pathophysiology of ORN is based on the concept of radiation-induced fibrosis, a new therapeutic medical regimen has been proposed comprising the combination of pentoxifylline, tocopherol and clodronate (PENTOCLO). A 55-year-old woman presented with grade III ORN with large intraoral bone exposure, a fracture of the left posterior horizontal branch and an orocutaneous fistula. Because she refused surgery, medical treatment with PENTOCLO was proposed. After 55months of treatment, there was complete mucosal coverage and complete consolidation of the fracture site around the orocutaneous fistula. PENTOCLO treatment can help some patients with grade III disease, as in this case. Further prospective randomized controlled trials are needed to confirm this result.

Osteoradionecrosis of the jaws: case series treated with adjuvant low-level laser therapy and antimicrobial photodynamic therapy

Background:

Osteoradionecrosis of the jaw (ORNJ) is the most severe and complex sequel of head and neck radiotherapy (RT) because of the bone involved, it may cause pain, paresthesia, foul odor, fistulae with suppuration, need for extra oral communication and pathological fracture. We treated twenty lesions of ORNJ using low-level laser therapy (LLLT) and antimicrobial photodynamic therapy (aPDT). The objective of this study was to stimulate the affected area to homeostasis and to promote the healing of the oral mucosa.

Methods:

We performed aPDT on the exposed bone, while LLLT was performed around the bone exposure (red spectrum) and on the affected jaw (infrared spectrum). Monitoring and clinical intervention occurred weekly or biweekly for 2 years.

Results:

100% of the sample presented clinical improvement, and 80% presented complete covering of the bone exposure by intact oral mucosa.

Conclusion:

LLLT and aPDT showed positive results as an adjuvant therapy to treat ORNJ.

Potential role of post-treatment follow-up FDG-PET CT to detect mandibular osteoradionecrosis: A case report

It was hypothesized that fluorodeoxyglucose (FDG) uptake on post-treatment follow-up positron emission tomography with computed tomography (PET CT; using PET CT to monitor and rule out recurrence and metastasis of head and neck carcinoma) would be useful for detecting and understanding the disease state of osteoradionecrosis (ORN) of the jaw. The present study included 14 patients who developed mandibular ORN following radiation therapy (RT) for head and neck cancer and underwent follow-up PET CT several times following RT. Areas exhibiting FDG uptake were retrospectively assessed on post-treatment follow-up PET CT images and were classified into three types: Spot type: Only spot accumulation of FDG; localized type: Accumulation of FDG restricted to within the bone resorption area; extensive type: Accumulation of FDG extending into surrounding soft tissue. PET classification at the time of clinical diagnosis of mandibular ORN in the 14 patients demonstrated the extensive type in 43%, localized type in 36% and spot type in 21%. An increased area of FDG uptake around the ORN was revealed retrospectively on post-treatment follow-up FDG PET-CT images in 50% of patients. Alterations in PET classification included spot type to localized type in 36% and localized type to extensive type in 14%. A significantly increased number of patients with extensive-type ORN (P=0.026) required surgery. Post-treatment follow-up FDG-PET CT may be useful for early detection and better understanding of ORN.