Department of Electrical and Computer Engineering, University of British Columbia, 2332 Main Mall, Vancouver, BC, Canada.
Can J Anaesth. 2010 Apr;57(4):313-21. doi: 10.1007/s12630-009-9252-1.
In conventional practice of epidural needle placement, determining the interspinous level and choosing the puncture site are based on palpation of anatomical landmarks, which can be difficult with some subjects. Thereafter, the correct passage of the needle towards the epidural space is a blind "feel as you go" method. An aim-and-insert single-operator ultrasound-guided epidural needle placement is described and demonstrated.
Nineteen subjects undergoing elective Cesarean delivery consented to undergo both a pre-puncture ultrasound scan and real-time paramedian ultrasound-guidance for needle insertion. Following were the study objectives: to measure the success of a combined spinal-epidural needle insertion under real-time guidance, to compare the locations of the chosen interspinous levels as determined by both ultrasound and palpation, to measure the change in depth of the epidural space from the skin surface as pressure is applied to the ultrasound transducer, and to investigate the geometric limitations of using a fixed needle guide.
One subject did not participate in the study because pre-puncture ultrasound examination showed unrecognizable bony landmarks. In 18 of 19 subjects, the epidural needle entered the epidural space successfully, as defined by a loss-of-resistance. In two subjects, entry into the epidural space was not achieved despite ultrasound guidance.Eighteen of the 19 interspinous spaces that were identified using palpation were consistent with those determined by ultrasound. The transducer pressure changed the depth of the epidural space by 2.8 mm. The measurements of the insertion lengths corresponded with the geometrical model of the needle guide, but the needle required a larger insertion angle than would be needed without the guide.
This small study demonstrates the feasibility of the ultrasound-guidance technique. Areas for further development are identified for both ultrasound software and physical design.
在传统的硬膜外针放置实践中，确定棘突间水平并选择穿刺点是基于对解剖学标志的触诊，而对于某些患者来说，这可能会很困难。此后，正确地将针朝向硬膜外腔是一种盲目“摸着石头过河”的方法。本文介绍并演示了一种单点操作者超声引导下的硬膜外针置管方法。
19 名接受择期剖宫产的受试者同意同时进行预穿刺超声扫描和实时旁正中超声引导下的针插入。研究目的如下：测量实时引导下联合腰硬联合穿刺针插入的成功率，比较超声和触诊确定的选择棘突间水平的位置，测量施加在超声换能器上时从皮肤表面到硬膜外腔的深度变化，并研究使用固定针引导的几何限制。
19 名受试者中，有 1 名受试者因预穿刺超声检查显示不可识别的骨标志而未参与研究。在 19 名受试者中的 18 名中，硬膜外针成功进入硬膜外腔，这是通过阻力丧失来定义的。在 2 名受试者中，尽管进行了超声引导，但仍未能进入硬膜外腔。通过触诊确定的 19 个棘突间间隙中有 18 个与超声确定的一致。换能器压力使硬膜外腔的深度改变了 2.8 毫米。插入长度的测量结果与针引导的几何模型相对应，但与没有引导器时相比，针需要更大的插入角度。
这项小型研究证明了超声引导技术的可行性。确定了进一步开发超声软件和物理设计的领域。
