核素扫描对成年犬股骨热灭活后再血管化的评价

Bone scintigraphy in evaluating revascularization of the heat devitalised autografts in adult dogs

目的建立长骨微波高温灭活的动物模型，将其再血管化过程的核素骨扫描（ＥＣＴ）表现与病理评价进行对比。方法选用成年杂种犬１６条，游离一侧股骨约８ｃｍ，隔热材料保护周围组织，间距２５ｃｍ置入微波天线２根，间断加热，维持骨皮质表面温度５０～６０℃３０分钟。术后不同时间进行ＥＣＴ检查，结合四环素荧光标记、印度墨汁灌注、ＨＥ染色等处理。结果通过微血管造影、四环素荧光标记等方法证实约有５ｃｍ～６ｃｍ骨段在灭活后完全失去血运。灭活骨段２周时无明显再血管化，ＥＣＴ表现为冷区。１２～１６周灭活骨段部分恢复血运，ＨＥ染色显示以骨吸收为主，仅见少量成骨，但ＥＣＴ显像均超过健侧对照。术后１年灭活骨段已恢复丰富血运伴明显原位性新骨形成，ＥＣＴ显像强度略低于健侧对照。结论早期ＥＣＴ的强阳性表现并不能反应热灭活皮质骨的活性，但却反应了良好的再血管化能力。

Objective To establish an animal model of microwave hyperthermic devitalization of long bones and compare bone scintigraphy of the devitalised bone with pathologic examination. Method 16 Mongrel adult dogs were used. Enght 8 cm of one femur of each dog was exposed and isolated by heat proof material.Two microwave antennas were inserted into the medullary cavity at a distance of 2 5 cm,and the bone was heated intermittently to maintain a surface temperature of 50℃ to 60℃ for 30 minutes.Bone scintigraphy was carried out at different postoperative time,combined with tetracycline labeling,microangiography with Indian ink and HE staining. Result About 5 cm～6 cm of segmental femur was deprived of blood supply after devitalization which was confirmed by microangiography and negative labeling of tetracyclines.At two weeks, the devitalised bone demonstrated a cold region on the scintiscan and no revascularization in microangiography.12～16 weeks after the operation,partial devitalised bone was revascularized and HE staining showed widel bone resorption and minimum formation of new bone.However,the radionuclide uptakes of the devitalised segments were greater than those of the normal femurs.At oneyear,the devitalised segment was well(not completely) revascularised and showed evident appositional new bone formation.The scintigraphic bone imaging was slightly lower than that of the normal femur. Conclusion A strong positive scintiscan in early stage might demonstrate a good potential of revascularization of the heat devitalised cortical bone rather than its viability.And the scintiscans of long term follow up more than one year should be more informative.