Higgins Thomas F, Casey Virginia, Bachus Kent
University of Utah Department of Orthopaedics, Salt Lake City, Utah 84108, USA.
J Orthop Trauma. 2007 Mar;21(3):192-7. doi: 10.1097/BOT.0b013e318038d952.
To compare the heat generation and pressure generation of a prototype irrigating aspirating intramedullary reaming system to traditional stepwise reaming.
This in vitro study used 8 pairs of fresh-frozen human cadaver tibias. Thermocouples were mounted in the mid-diaphysis and distal diaphysis. A pressure transducer was placed distally to assess intramedullary pressure, a load cell measured axial load was applied by the surgeon, and the entire construct was placed in a 37 degrees C saline bath. One specimen from each pair underwent single-pass reaming with the prototype reamer irrigator aspirator (RIA), and the contralateral limb underwent standard stepwise reaming. All variables were recorded.
There were no significant differences in pressure applied to the load cells during reaming. The maximum temperatures reached in the distal diaphysis in the RIA group (42.0 +/- 9.1 degrees C) were significantly lower (P = 0.025) than in the standard reaming group (58.7 +/- 15.9 degrees C). The maximum pressure generated in the distal tibia in the RIA group (32.7 +/- 39.4 kPa) was significantly higher (P = 0.019) than in the standard reaming group (17.0 +/- 32.6 kPa).
This study demonstrated substantially decreased temperatures with the RIA prototype when compared with standard stepwise reaming. It appears that the continuous flow of room temperature saline irrigant into the system manages to cool the cortical bone, despite the aggressive nature of a single-pass reaming method. However, in this model, contrary to the findings of other studies, the RIA system did generate higher pressures in the distal tibial metaphysis, perhaps as a result of congestion within the outflow of the RIA system. The results of this study confirm that cortical heat generation is not a problem but definitely indicate further development of this prototype aspirator function is warranted, followed by careful in vivo evaluation.
比较一种原型冲洗吸引髓内扩髓系统与传统逐步扩髓的产热和压力产生情况。
这项体外研究使用了8对新鲜冷冻的人体尸体胫骨。热电偶安装在骨干中部和远端。在远端放置一个压力传感器以评估髓内压力，一个测力传感器测量外科医生施加的轴向负荷，整个装置置于37℃的盐水中。每对标本中的一个用原型扩髓冲洗吸引器（RIA）进行单次扩髓，对侧肢体进行标准逐步扩髓。记录所有变量。
扩髓过程中施加在测力传感器上的压力无显著差异。RIA组远端骨干达到的最高温度（42.0±9.1℃）显著低于标准扩髓组（58.7±15.9℃）（P = 0.025）。RIA组胫骨干远端产生的最大压力（32.7±39.4kPa）显著高于标准扩髓组（17.0±32.6kPa）（P = 0.019）。
本研究表明，与标准逐步扩髓相比，RIA原型系统的温度显著降低。尽管单次扩髓方法具有侵袭性，但室温盐水冲洗液持续流入系统似乎能够冷却皮质骨。然而，在该模型中，与其他研究结果相反，RIA系统在胫骨干远端确实产生了更高的压力，这可能是由于RIA系统流出道内的充血所致。本研究结果证实皮质骨产热不是问题，但明确表明该原型吸引器功能值得进一步开发，随后进行仔细的体内评估。
