实验性长骨缺损的一期骨外固定治疗

Experimentalstudiesofsegmentalbonedefectstreatedbyskeletalexternalfixation

为观察加压外固定的骨断端和骨延长区微循环的重建过程及血流动力学的变化，作者以羊胫骨干骨缺损为模型，进行了微血管造影和铸型、墨汁灌注透明切片、放射微球法局部血流量测定等观察。结果证实延长区血管极丰富，与延长速度（１．０ｍｍ／天）同步生长，并随延长区新生骨皮质出现逐渐向正常皮质骨血管系统衍变。延长结束２周时血流量达高峰（５４．５６±８．５３ｍｌ／ｍｉｎ／１００ｇ）。骨缺损断端皮质血管于术后７周长入间隙并相互吻合，此时血流量达（３１．８２±２．８５ｍｌ／ｍｉｎ／１００ｇ）。术后１２周仍比正常皮质骨血流量（３．０２±０．１３ｍｌ／ｍｉｎ／１００ｇ）高２倍，断端对位良好，呈一期愈合。作者认为胫骨干骺端血循环丰富，延长区骨修复迅速，加压外固定同样可出现骨折一期愈合。

Bonytissueofanaverageof13.6%oftheoriginallength(OL)wasresectedfromthetibiashaftin26maturegoats.Thefractureendswerecompresivelyfixedwithskeletalexternalfixa-tion(SEF).Simultaneously,uppermetaphysiotomywasperformedtolengthenthetibiawithalengthen-ingrateof1.0mm/dandatotallengthening20.14%ofOL.Therestorationofbloodcirculationandthehemodynamicchangesduringtherepairprocessofthecompressivelyfixedboneendsandthemeta-physiotomysitewerestudiedwithangiography,microvascularcast,Chineseinkpermeatedtransparentthickslide,andradioactivemicrospheremeasurementofregionalbloodflow(RBF).Itwasfoundthattherewereabundantvascularnetworksinthelengthenedzone.Thebloodvesselsnotonlycouldkeepupwiththesamelengtheningrateofgrowing,butalsoweregradulyconvertedintotheHaversiansysteminthenewlyformedcortexofthelengthenedarea.Inthe2ndweekafterthecesationofbonelengthen-ing,theRBFofthelengthenedzonereachedthemaximum(54.56±8.53ml/min/100g).Itwasalsofoundthatinthe7thpostoperativewek,theveselsofthecortexoftheosteotomyshorteningendscouldgrowacrossthespacebetweenthemandanastomosewitheachother.TheRBFatthistimewas31.82±2.85ml/min/100g.Inthe12thweekafteroperation,theRBFwasstil2timeshigherthanthatofthenormalcortex(3.02±0.13ml/min/100g).Theprimaryhealingcouldbeobservedunderthewelreductionandstablecompresiveexternalfixation.ThesefindingsprovideatheoreticalbasisfortheclinicalapplicationofSEFforthetreatmentoftibialshaftdefectsornonunionassociatedwithlimbshortening.