Bae H G, Choi S K, Joo K S, Kim B T, Doh J W, Lee K S, Shin W H, Yun I G, Byun B J
Department of Neurosurgery, Soonchunhyang University Hospital, Seoul, South Korea.
Neurosurgery. 1999 Apr;44(4):841-6. doi: 10.1097/00006123-199904000-00082.
In the posterolateral extraforaminal and anterolateral retroperitoneal approaches to lumbar spinal lesions, the neural structures in the lumbar extraforaminal region are unfamiliar to many spinal surgeons. The purpose of this study was to determine the normal anatomic morphometric parameters for all lumbar nerve roots around their exits, from the intervertebral foramen to the surrounding bony structure.
A total of 15 adult fixed cadavers were studied. The extraforaminal course of the lumbar nerve roots and the forming plexus were measured segmentally, using standard calipers, and we selected the shortest distance from the bony landmarks to the nerve roots in the horizontal plane. The bony landmarks were the most medial superior border of the transverse process (TP), the most medial inferior border of the TP, the tip of the superior articular process, and the most dorsolateral margin of the intervertebral disc space. In addition, the angle of each root exiting from the intervertebral foramen was measured using a goniometer.
The mean distance from the medial superior border of the TP to the upper segment of the nerve root was 5.1 to 6.4 mm at L2-L5. The mean distance from the medial inferior border of the TP to the corresponding nerve root was 8.5 mm at L2 and L3 and 6 mm at L4 and L5. The mean distance from the tip of the superior articular process to the most dorsal border of the descending nerve trunk was 19 mm at L2 and L3 and 22 mm at L4 and L5. The main lumbar nerve trunk was located close to the most dorsolateral surface of the vertebral body and the intervertebral disc space, and it was topographically arranged dorsoventrally from the L5 to L2 nerve components. The average widths of the nerve trunk were 10, 14, and 25 mm at L3-L4, L4-L5, and L5-S1, respectively. The mean angles of the exiting roots in the extraforaminal region were 16 degrees at L2 and L3 and 25 degrees at L4 and L5.
The lumbar nerve component, including both the lumbar trunk and each exiting nerve root in the extraforaminal region (the so-called "danger zone"), was located anteriorly at a distance more than 5 mm from the TP, more than 19 mm from the superior articular process, and up to 25 mm from the intervertebral disc space. Based on our results, the danger zone occupied up to 25 mm forward from the intervertebral foramen at the lower lumbar segments. Therefore, during operations such as percutaneous posterolateral procedures and open posterolateral or anterolateral approaches, great care should be taken within 25 mm of the extraforaminal region, especially for the lower lumbar spine.
在腰椎病变的后外侧椎间孔外和前外侧腹膜后入路中，许多脊柱外科医生对腰椎椎间孔外区域的神经结构并不熟悉。本研究的目的是确定所有腰神经根在其出口周围，从椎间孔到周围骨性结构的正常解剖形态学参数。
共研究了15具成年固定尸体。使用标准卡尺对腰神经根的椎间孔外走行及形成的神经丛进行分段测量，并在水平面上选择从骨性标志到神经根的最短距离。骨性标志为横突最内侧上缘、横突最内侧下缘、上关节突尖以及椎间盘间隙最背外侧缘。此外，使用角度计测量各神经根从椎间孔穿出的角度。
L2-L5水平，从横突内侧上缘到神经根上段的平均距离为5.1至
6.4毫米。L2和L3水平，从横突内侧下缘到相应神经根的平均距离为8.5毫米，L4和L5水平为6毫米。L2和L3水平，从上关节突尖到下行神经干最背侧缘的平均距离为19毫米，L4和L5水平为22毫米。腰神经主干靠近椎体和椎间盘间隙的最背外侧表面，在地形上从L5至L2神经成分呈背腹排列。L3-L4、L4-L5和L5-S1水平神经干的平均宽度分别为10、14和25毫米。椎间孔外区域神经根穿出的平均角度在L2和L3为16度，在L4和L5为25度。
腰神经成分，包括腰神经主干和椎间孔外区域（即所谓的“危险区”）的每一条穿出神经根，位于前方距横突超过5毫米、距上关节突超过19毫米、距椎间盘间隙达25毫米处。根据我们的结果，在下腰椎节段，危险区从椎间孔向前占据达25毫米。因此，在诸如经皮后外侧手术以及开放后外侧或前外侧入路等手术过程中，在椎间孔外区域25毫米范围内应格外小心，尤其是在下腰椎。
