Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
Eur Spine J. 2013 May;22 Suppl 3(Suppl 3):S461-5. doi: 10.1007/s00586-012-2634-z. Epub 2012 Dec 28.
To evaluate L5 nerve root injuries caused by outwardly misplaced S1 pedicle screws. Pedicle screws remain the criterion standard for fixation of L5-S1 to correct lumbosacral instability. When inserting S1 pedicle screws, it is possible to injure the L5 nerve root if screws are inserted outwardly and the tip of the screw perforates the anterior cortex of the sacrum. Despite this risk, to our knowledge this type of injury has never been reported as a case series.
We experienced 2 cases of L5 nerve root injury caused by outwardly-inserted S1 pedicle screws. In both cases, bilateral S1 pedicle screws were inserted outwardly using a free-hand technique, and on one side, screws induced severe pain by impinging on an L5 root. Computed tomography after the selective rootgraphy of the injured nerve showed the nerve compressed laterally by screw threads in Case 1 and crushed between the screw threads and the sacral body in Case 2.
In both cases, leg pain disappeared immediately after the infiltration of the nerve with lidocaine, but symptoms recurred within a few days in Case 1 and within an hour in Case 2. Conservative treatment of three spinal nerve infiltrations was effective in Case 1, but reinsertion of the rogue screw was necessary in Case 2.
Surgeons should recognize that lateral inclination of S1 pedicle screws can cause L5 nerve root injury, which may require reinsertion of the screw, especially in cases where insertion is difficult because of overlapping surrounding muscle or bony tissue.
评估因 S1 椎弓根螺钉向外移位而导致的 L5 神经根损伤。椎弓根螺钉仍然是固定 L5-S1 以矫正腰骶部不稳定的标准方法。当插入 S1 椎弓根螺钉时，如果螺钉向外插入并且螺钉尖端穿透骶骨前皮质，就有可能损伤 L5 神经根。尽管存在这种风险，但据我们所知，这种类型的损伤从未作为病例系列报告过。
我们遇到了 2 例因向外插入的 S1 椎弓根螺钉引起的 L5 神经根损伤的病例。在这 2 个病例中，均使用徒手技术向外侧插入双侧 S1 椎弓根螺钉，其中一侧螺钉因压迫 L5 神经根而引起严重疼痛。受伤神经选择性神经根造影后的 CT 显示，在病例 1 中螺钉螺纹侧向压迫神经，在病例 2 中螺钉螺纹和骶骨体之间挤压神经。
在这 2 个病例中，向神经内注入利多卡因后腿部疼痛立即消失，但在病例 1 中数天后症状再次出现，在病例 2 中 1 小时后再次出现。对 3 例脊神经根浸润进行的保守治疗在病例 1 中有效，但病例 2 中需要重新插入脱位螺钉。
外科医生应该认识到 S1 椎弓根螺钉的外侧倾斜可能导致 L5 神经根损伤，可能需要重新插入螺钉，特别是在因周围肌肉或骨组织重叠而导致插入困难的情况下。
