Clifton William, Edwards Steve, Dove Conrad, Damon Aaron, Simon Leslie, Rosenbush Kristin, Nottmeier Eric, Quinones-Hinojosa Alfredo, Pichelmann Mark
Department of Neurological Surgery, Mayo Clinic Florida, Jacksonville, Florida, USA.
Department of Neurological Surgery, Mayo Clinic Florida, Jacksonville, Florida, USA.
World Neurosurg. 2019 Jul;127:e738-e744. doi: 10.1016/j.wneu.2019.03.256. Epub 2019 Apr 2.
Atlantoaxial fusion often requires C2 nerve transection for complete C1 lateral mass exposure. Nerve transection is made ideally at the preganglionic segment proximal to the dorsal root ganglion to minimize the risk of postoperative dysesthesias. If the nerve is transected too proximally, cerebrospinal fluid leak may be encountered by violation of the dura and arachnoid where the sensory and motor nerve rootlets exit the subarachnoid space. In this study we aimed to quantify the length of the C2 nerve preganglionic segment using cadaveric specimens and develop a method for reliable intraoperative localization for sectioning during C1-2 arthrodesis.
Using microsurgical techniques, 16 C2 nerves from 8 frozen and injected cadaveric cervical spine specimens were dissected. Two key measurements were taken to establish a reliable method of preganglionic segment identification. The "sweet spot" for nerve transection was based on the approximate location of the midpoint of the preganglionic segment.
The final determination of the ideal spot for C2 nerve transection using these calculations was 3 mm lateral to the medial border of the lateral mass.
This anatomic study found remarkable consistency in the preganglionic segment length. The medial border of the lateral mass appeared to be a consistently reliable landmark for identification of the preganglionic segment of the C2 nerve root. By using relationships between known anatomic structures intraoperatively, safety of atlantoaxial fixation can be optimized to maximize complication avoidance and satisfactory patient outcomes.
寰枢椎融合术通常需要切断C2神经以充分暴露C1侧块。理想情况下，神经切断应在背根神经节近端的节前段进行，以尽量降低术后感觉异常的风险。如果神经切断位置过于靠近近端，在感觉和运动神经根穿出蛛网膜下腔处，硬脑膜和蛛网膜可能会被破坏，从而导致脑脊液漏。在本研究中，我们旨在使用尸体标本量化C2神经节前段的长度，并开发一种在C1-2关节固定术中进行可靠的术中定位以进行切断的方法。
使用显微外科技术，从8个冷冻并注射过的尸体颈椎标本中解剖出16条C2神经。进行了两项关键测量以建立一种可靠的节前段识别方法。神经切断的“最佳点”基于节前段中点的大致位置。
使用这些计算得出的C2神经切断理想点的最终确定位置为侧块内侧缘外侧3mm处。
这项解剖学研究发现节前段长度具有显著的一致性。侧块内侧缘似乎是识别C2神经根节前段的始终可靠的标志。通过术中利用已知解剖结构之间的关系，可以优化寰枢椎固定的安全性，以最大程度地避免并发症并获得满意的患者预后。
