骨水泥阻塞骨干髓腔后远侧骨干骨内压和骨血流改变的实验研究

目的]探讨骨水泥阻塞股骨近中段骨干髓腔后对股骨远端骨内压和骨血流的影响.方法]采取兔左侧股骨髓腔内灌注PMMA骨水泥而右侧不灌注作为正常对照的方法,制作骨水泥阻塞股骨近中段骨干髓腔的兔动物模型.将32只实验兔分成5组,随机取出8只不做模型作为正常对照组,其余24只制作模型后,根据不同的观察时间段随机分成术后当天（T0）、术后4周（T4）、术后8周（T8）、术后16周（Ti6）4个观察组,每组6只.使用生理测压仪,对正常和模型动物双侧股骨远端骨内压进行测量和比较.采用核素骨显像（ECT）方法,对模型动物双侧股骨远端动态和静态显像进行检测和比较.结果]（1）骨内压：正常兔股骨远端双侧骨内压无差异性（P＞0.05）：T0、T4、T8、T16实验侧骨内压明显增高,双侧有差异性（P＜0.01）.造模后在不同观察时间段对照侧骨内压均无差异性（P＞0.05）,实验侧处于持续骨内高压状态,T0与T4、T0与T8、T0与T16、T4与T8、T8与T16均无差异性（P＞0.05）,T4与T16有差异性（P＜0.05）;（2）核素骨显像：T0、T4实验侧核素计数均比对照侧明显降低,T8、T16实验侧核素计数均超过对照侧,T16最高;各时间段实验侧/对照侧核素计数比值中T0与T8、T0与T16、T4与T16、T8与T16、T4与T8均有差异性（P＜0.05）,而T0与T4无差异性（P＞0.05）.核素骨动态和静态显像的变化趋势完全一致.结论]骨水泥阻塞股骨近中段骨干髓腔后严重破坏了骨内和髓内的血液循环状态,引起了局部血流动力学的改变.导致股骨远端的骨内压和骨血流发生了一系列的变化,骨内压持续升高并长期存在.

Intraosseous pressure and blood flow of the distal femoral shiaft after blocking the proximal and middle femoral medullary cavity

Objective]To explore the effect on the distal femoral intraosseous pressure(IP) an blood flow after blocking proximal and middle femoral medullary cavity(FMC) with bone cement.Method] Twenty-four rabbit models were established whose proximal and middle FMC of left side was blocked with PMMA,while the right side femurs as control side without blocking,then randomly divided into 4 groups based on observation time-points postoperatively: 0 day(T_0),4th week(T_4),8th week(T_8) and 16th week(T_(16)) respectively.Another 8 rabbits without any blocking were as control group.Physiological pressure measuring instrument was used to detect,analyse and compare IP of bilateral distal FMC,radio nuclide bone imaging(RBI) was used to detect and compare the dynamic and static images of bilateral distal femurs,the same interesting region of distal femurs were selected and fixed during dynamic and static phases of blood flow,the nuclide counting ratio was compared between experimental and control sides.Result]There was no static difference(SD) of the IP between the both T_4,T_8 and T_(16),the IP of experimental side increased notably as compared with that of control side(P<0.05),while there was no SD of IP at different time points that sin the control sides.(P>0.05) The experimental sides showed continous high IP,but declined at T_(16).There was no SD between IP of T_0 and T_4, IP T_0 and T_8,IP T_0 and T_(16),IP T_4 and T_0,IP T_8 and T_(16)(P>0.05) except IP between T_4 and T_(16)(P<0.05).Compared the dynamic and static images at different time-points,the RBI of the experimental sides was lower than that of the control sides at T_4,while higher at T_8 and the highest at T_(16).There was no SD of the nuclide counting ratio between T_0 and T_8,T0 and T_(16),T_4 and T_(16),T_8 and T_(16),T_4 and T_8,respectively(P<0.05),except between T_0 and T_4(P>0.05).the dynamic and static RBI showed the same change tendency.Conclusion]The intraosseous and intramedullary blood circulation is severely damaged after blocking of the proximal and middle FMC with bone cement,it induces a long time high IP and a series of changes of blood flow at distal femur.