Vloka J D, Hadzić A, Lesser J B, Kitain E, Geatz H, April E W, Thys D M
Department of Anesthesiology, St. Luke's-Roosevelt Hospital Center, New York, NY 10025, USA.
Anesth Analg. 1997 Feb;84(2):387-90. doi: 10.1097/00000539-199702000-00028.
Sciatic nerve block in the popliteal fossa is associated with a highly variable success rate. Frequently, anesthesia is profound in the distribution of both the tibial (TN) and common peroneal nerves (CPN), although the response to nerve stimulation or paresthesia is obtained in the distribution of one division of the nerve. However, anesthesia in the distribution of only one division of the nerve is also a common occurrence under apparently identical clinical circumstances. Looking for a possible role of a common epineural sheath in these phenomena, we injected dye into the epineural sheath of the tibial nerve in 10 cadaver legs and observed its spread within the sheath. Injections of 15 mL and 30 mL of the dye resulted in a proximal spread of 147 +/- 34 mm and 172 +/- 50 mm, respectively, from the injection point 10 cm below the popliteal fossa crease. In a majority of the legs, the dye reached the division of the sciatic nerve in the popliteal fossa, bathing both the TN and CPN. Gross inspection and histologic examination of the sciatic nerve specimens revealed a common epineural sheath enveloping the TN and CPN. The presence of the common epineural sheath and its characteristics may have important clinical implications for sciatic nerve blockade in the popliteal fossa.
腘窝坐骨神经阻滞的成功率变化很大。通常，尽管在神经的一个分支分布区域获得了对神经刺激或异感的反应，但胫神经（TN）和腓总神经（CPN）分布区域的麻醉效果都很显著。然而，在明显相同的临床情况下，仅一个神经分支分布区域出现麻醉的情况也很常见。为了探究共同神经外膜鞘在这些现象中可能起到的作用，我们在10条尸体下肢的胫神经神经外膜鞘内注射了染料，并观察其在鞘内的扩散情况。分别注射15 mL和30 mL染料后，染料从腘窝皱襞下方10 cm处的注射点向近端扩散的距离分别为147±34 mm和172±50 mm。在大多数下肢中，染料到达了腘窝处坐骨神经的分支，使胫神经和腓总神经都被浸染。对坐骨神经标本的大体检查和组织学检查显示，有一个共同的神经外膜鞘包裹着胫神经和腓总神经。共同神经外膜鞘的存在及其特征可能对腘窝坐骨神经阻滞具有重要的临床意义。
