Kast E, Mohr K, Richter H-P, Börm W
Neurosurgical Department, Kantonsspital Winterthur, Brauerstr. 15, Winterthur, 8401, Switzerland.
Eur Spine J. 2006 Mar;15(3):327-34. doi: 10.1007/s00586-004-0861-7. Epub 2005 May 24.
Today, posterior stabilization of the cervical spine is most frequently performed by lateral mass screws or spinous process wiring. These techniques do not always provide sufficient stability, and anterior fusion procedures are added secondarily. Recently, transpedicular screw fixation of the cervical spine has been introduced to provide a one-stage stable posterior fixation. The aim of the present prospective study is to examine if cervical pedicle screw fixation can be done by low risk and to identify potential risk factors associated with this technique. All patients stabilized by cervical transpedicular screw fixation between 1999 and 2002 were included. Cervical disorders included multisegmental degenerative instability with cervical myelopathy in 16 patients, segmental instability caused by rheumatoid arthritis in three, trauma in five and instability caused by infection in two patients. In most cases additional decompression of the spinal cord and bone graft placement were performed. Pre-operative and post-operative CT-scans (2-mm cuts) and plain X-rays served to determine changes in alignment and the position of the screws. Clinical outcome was assessed in all cases. Ninety-four cervical pedicle screws were implanted in 26 patients, most frequently at the C3 (26 screws) and C4 levels (19 screws). Radiologically 66 screws (70%) were placed correctly (maximal breach 1 mm) whereas 20 screws (21%) were misplaced with reduction of mechanical strength, slight narrowing of the vertebral artery canal (<25%) or the lateral recess without compression of neural structures. However, these misplacements were asymptomatic in all cases. Another eight screws (9%) had a critical breach. Four of them showed a narrowing of the vertebral artery canal of more then 25%, in all cases without vascular problems. Three screws passed through the intervertebral foramen, causing temporary paresis in one case and a new sensory loss in another. In the latter patient revision surgery was performed. The screw was loosened and had to be corrected. The only statistically significant risk factor was the level of surgery: all critical breaches were seen from C3 to C5. Percutaneous application of the screws reduced the risk for misplacement, although this finding was not statistically significant. There was also a remarkable learning curve. Instrumentation with cervical transpedicular screws results in very stable fixation. However, with the use of new techniques like percutaneous screw application or computerized image guidance there remains a risk for damaging nerve roots or the vertebral artery. This technique should be reserved for highly selected patients with clear indications and to highly experienced spine surgeons.
如今，颈椎后路稳定术最常通过侧块螺钉或棘突钢丝固定来实施。这些技术并不总能提供足够的稳定性，因此常需二期追加前路融合手术。近来，颈椎经椎弓根螺钉固定术被引入，以提供一期稳定的后路固定。本前瞻性研究的目的是检验颈椎椎弓根螺钉固定术能否以低风险完成，并确定与该技术相关的潜在风险因素。纳入了1999年至2002年间接受颈椎经椎弓根螺钉固定术的所有患者。颈椎疾病包括16例多节段退行性不稳定伴颈椎脊髓病、3例类风湿关节炎所致节段性不稳定、5例创伤以及2例感染所致不稳定。在大多数情况下，还进行了脊髓减压和植骨。术前和术后的CT扫描（层厚2毫米）及X线平片用于确定对线情况和螺钉位置的变化。对所有病例进行了临床结果评估。26例患者共植入94枚颈椎椎弓根螺钉，最常植入的节段是C3（26枚螺钉）和C4（19枚螺钉）。影像学检查显示，66枚螺钉（70%）位置正确（最大偏差1毫米），而20枚螺钉（21%）位置不当，导致机械强度降低、椎动脉管轻度狭窄（<25%）或侧隐窝狭窄，但未压迫神经结构。然而，所有这些位置不当的情况均无症状。另外8枚螺钉（9%）出现严重偏差。其中4枚显示椎动脉管狭窄超过25%，但所有病例均无血管问题。3枚螺钉穿过椎间孔，1例导致暂时麻痹，另1例出现新的感觉丧失。后1例患者接受了翻修手术。螺钉松动，必须进行纠正。唯一具有统计学意义的风险因素是手术节段：所有严重偏差均见于C3至C5节段。经皮置入螺钉降低了位置不当的风险，尽管这一发现无统计学意义。此外，还存在明显的学习曲线。颈椎经椎弓根螺钉内固定可实现非常稳定的固定。然而，使用经皮螺钉置入或计算机图像引导等新技术仍存在损伤神经根或椎动脉的风险。该技术应仅用于有明确适应证的高度选择的患者以及经验丰富的脊柱外科医生。
