大鼠胫骨放射性骨坏死模型的建立及评估

目的:建立大鼠胫骨放射性骨坏死动物模型,通过大体观察和组织病理学方法对该模型进行评估.方法:选择6只Sprague-Dawley (SD)大鼠(体重200～250 g),使用直线加速器对SD大鼠右侧胫骨区进行60 Gy的照射,照射分4次完成,每次间隔2周.放疗后1、2、3及4周,大体观察放疗区变化,评估大鼠下肢放疗后毛发及皮肤改变.放疗后4周,利用组织病理学方法比较放疗区与非放疗区骨组织的变化,通过影像学检查判断骨破坏情况.采用SPSS 13.0软件包对数据进行统计学分析.结果:SD大鼠在完成放疗后1周,放疗区无显著变化,但与对侧相比,放疗侧下肢爪心颜色明显变红;放疗后2～3周,放疗区毛发脱落;放疗后4周,放疗区毛发完全脱落,且皮肤发生溃疡;放疗4周后组织病理切片H-E染色显示,放疗侧骨量显著少于对照侧,包括骨壁厚度、骨髓细胞及骨小梁数目.影像学检查发现放疗区明显骨破坏.结论:使用60 Gy剂量对SD大鼠胫骨分别进行4次照射,可成功构建大鼠胫骨放射性骨坏死模型.     

Human bone marrow stromal cells display variable anatomic site-dependent response and recovery from irradiation

Objectives

Orofacial bone is commonly affected by osteoradionecrosis (ORN) during head and neck cancer radiotherapy possibly due to interactions of several factors including radiation damage to resident bone marrow stromal cells (BMSCs). Irradiation causes DNA damage, triggers p53-dependent signalling resulting in either cell-cycle arrest or apoptosis. In same individuals, disproportionately higher rapid growth of orofacial BMSCs relative to those of axial/appendicular bones suggests their response to radiation is skeletally site-specific. We hypothesised that survival and osteogenic recovery capacity of irradiated human BMSCs is site-dependent based on anatomic skeletal site of origin.

Methods

Early passage BMSCs from maxilla, mandible and iliac crest of four normal volunteers were exposed to 2.5 to 10 Gy gamma radiation to evaluate clonogenic survival, effects on cell cycle, DNA damage, p53-related response and in vivo osteogenic regenerative capacity.

Results

Orofacial bone marrow stromal cells (OF-MSCs) survived higher radiation doses and recovered quicker than iliac crest (IC-MSCs) based on clonogenic survival, proliferation and accumulation in G₀G₁ phase. Post-irradiation p53 level was relatively unchanged but expression of p21, a downstream effector was moderately increased in OF-MSCs. Re-establishment of in vivo bone regeneration was delayed more in irradiated IC-MSCs relative to OF-MSCs.

Conclusions

Effect of irradiation on human BMSCs was skeletal site-specific with OF-MSCs displaying higher radio-resistance and quicker recovery than IC-MSCs.     

Management of patients at risk of osteoradionecrosis: results of survey of dentists and oral & maxillofacial surgery units in the United Kingdom,and suggestions for best practice

We aimed to find out whether dental practitioners take specific measures to identify patients who are at risk of osteoradionecrosis (ORN) of the jawbones; how oral and maxillofacial surgery units in the United Kingdom manage patients who have had radiotherapy and require dental extractions, and the evidence behind current practice.     

鼻咽癌放疗后颞骨放射性骨坏死的诊治

目的：探讨鼻咽癌放疗后颞骨放射性骨坏死的诊断和治疗。方法：21例（22耳）鼻咽癌放疗后颞骨放射性骨坏死患者，经耳镜及影像学检查16例17耳局限型，5例5耳弥漫型。17耳局限型及1耳弥漫型予耳内镜下死骨刮除术，4耳弥漫型行乳突根治加耳周带蒂筋膜转移填塞术。结果：局限型17耳中，12耳（70．6％）创面完全上皮化，无游离死骨形成而治愈；4耳（23．5％）好转，创面未完全上皮化，但随访无死骨形成；1耳（5．9％）未愈，呈进行性死骨发展。弥漫型5耳中，1耳行有限度的死骨刮除术，创面完全上皮化而治愈；乳突根治4耳中，治愈3耳，1耳死骨形成再次手术，仍有耳漏。结论：耳内镜及颞骨CT为该病提供不同特点的诊断价值，对局限型行局部死骨刮除术能获得较好的疗效，提高患者的生活质量；弥漫型手术选择应慎重，本病有进行性缓慢发展的可能，需定期随访。     

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.