Smith Paul N, Leditschke Anne, McMahon Damian, Sample Roxanne R, Perriman Diana, Prins Anne, Brüssel Thomas, Li Rachel W
Medical School, College of Medicine and Health Sciences, The Australian National University, Canberra, Australia.
J Orthop Res. 2008 Oct;26(10):1327-33. doi: 10.1002/jor.20564.
Intramedullary reamed nailing causes elevation in intramedullary pressure and extravazation of intramedullary contents into the venous blood system. This study investigated the effect of an intramedullary suction system, recently developed in our laboratory, on the pressure and fat extravazation in isolated bovine bone and a sheep model. During reaming, the pressure with and without suction was recorded at each step of the procedure. Hemodynamic parameters of mean arterial blood pressure, pulmonary artery pressure, pulmonary arterial CO(2) (PaCO(2)), heart rate, and oxygen saturation were monitored. Blood and lung tissue samples were collected for the examination of medullary fat intravazation. The increases of intramedullary pressure were dramatically reduced in the suction group (p < 0.05) in both in vitro and in vivo experiments. PaCO(2) was significantly lower in the suction group than nonsuction group (32 vs. 40 mmHg, respectively, p = 0.02), while oxygen saturation was higher in the suction group (99 vs. 91 mmHg, respectively, p = 0.009). Histological data revealed a significant higher count of fat emboli in sheep lung tissue in the nonsuction group. Total lipids in lung specimens was lower in the suction group (7.6 mg/g tissue) than in the nonsuction group (13.6 mg/g, p = 0.04). The suction system appears to control the surge in intramedullary pressure and therefore prevent fat embolism.
髓内扩髓钉固定会导致髓内压力升高以及髓内成分外渗至静脉血液系统。本研究调查了我们实验室最近研发的一种髓内吸引系统对离体牛骨和绵羊模型中压力及脂肪外渗的影响。在扩髓过程中，记录有吸引和无吸引情况下每个步骤的压力。监测平均动脉血压、肺动脉压、肺动脉二氧化碳分压（PaCO₂）、心率和血氧饱和度等血流动力学参数。采集血液和肺组织样本以检测髓内脂肪的外渗情况。在体外和体内实验中，吸引组的髓内压力升高均显著降低（p < 0.05）。吸引组的PaCO₂显著低于非吸引组（分别为32 mmHg和40 mmHg，p = 0.02），而吸引组的血氧饱和度更高（分别为99 mmHg和91 mmHg，p = 0.009）。组织学数据显示，非吸引组绵羊肺组织中的脂肪栓子数量显著更多。吸引组肺标本中的总脂质含量（7.6 mg/g组织）低于非吸引组（13.6 mg/g，p = 0.04）。该吸引系统似乎能够控制髓内压力的激增，从而预防脂肪栓塞。
