Shriners Hospital for Children, Philadelphia, Pennsylvania 19140, USA.
Neurosurgery. 2010 Feb;66(2):290-4; discussion 294-5. doi: 10.1227/01.NEU.0000363853.62897.94.
The placement of thoracic pedicle screws, particularly in the deformed spine, poses unique challenges, and a learning curve. We measured the in vivo accuracy of placement of thoracic pedicle screws by computed tomography in the deformed spine by a single surgeon over time.
After obtaining institutional review board approval, we retrospectively selected the first 30 consecutive patients who had undergone a posterior spinal fusion using a pedicle screw construct for adolescent idiopathic scoliosis by a single surgeon. The average patient age was 14 years, and their preoperative thoracic Cobb angle was, on average, 62.6 degrees. Patients were divided into 3 groups: group A, patients 1 to 10; group B, patients 11 to 20; and group C, patients 21 to 30. Intraoperative evaluation of all pedicle screws included probing of the pedicle screw tract, neurophysiologic monitoring, and fluoroscopic confirmation. Postoperative computed tomographic scans were evaluated by 2 spine surgeons, and a consensus read was established, as previously described (Kim YJ, Lenke LG, Bridwell KH, Cho YS, Riew KD. Free hand pedicle screw placement in the thoracic spine: is it safe? Spine. 2004;29(3):333-342), as (1) "in," axis of pedicle screw within the confines of the pedicle; or (2) "out," axis of pedicle screw outside the confines of the pedicle.
A total of 553 thoracic pedicle screws were studied (group A, n = 181; group B, n = 189; group C, n = 183) with 64 graded as out (medial, 35; lateral, 29), for an overall breach rate of 11.6%. When the breach rates were stratified by the surgeon's evolving experience, there was a temporal decrease in the breach rate (group A, 15.5%; group B, 10.6%; group C, 8.7%; P < .05). This decreased breach rate was reflected in fewer medial breaches over time (group A, 9.4%; group B, 5.8%; group C, 3.8%; P < .05). Similar trends were observed for the concave periapical screws, although statistical significance was not attained (group A, 21.2%; group B, 16.2%; group C, 10.5%).
The overall accuracy of placement of thoracic pedicle screws in the deformed spine was 88.4%, with no neurologic or visceral complications. One patient from group A returned to the operating room on postoperative day 2 for removal of an asymptomatic left T7 thoracic pedicle screw abutting the aorta. As surgeon experience increased, there was an overall decreased breach rate, which was mainly reflected in fewer medial breaches.
在变形的脊柱中，胸椎椎弓根螺钉的植入，尤其是在变形的脊柱中，具有独特的挑战和学习曲线。我们通过一位外科医生对 30 例连续接受青少年特发性脊柱侧凸后路脊柱融合术的患者的术后 CT 扫描，测量了在变形的脊柱中植入胸椎椎弓根螺钉的体内准确性。
获得机构审查委员会批准后，我们回顾性地选择了 30 例由同一位外科医生采用椎弓根螺钉系统治疗的特发性脊柱侧凸患者，这些患者连续接受了后路脊柱融合术。患者的平均年龄为 14 岁，术前胸椎 Cobb 角平均为 62.6 度。患者分为 3 组：A 组，患者 1 至 10 例；B 组，患者 11 至 20 例；C 组，患者 21 至 30 例。所有椎弓根螺钉的术中评估均包括椎弓根螺钉通道探查、神经生理监测和透视确认。术后对 2 位脊柱外科医生进行 CT 扫描评估，并建立了共识阅读，如前所述（Kim YJ、Lenke LG、Bridwell KH、Cho YS、Riew KD。徒手椎弓根螺钉置入在胸椎：安全吗？脊柱。2004；29（3）：333-342），如（1）“内”，椎弓根螺钉的轴在椎弓根的范围内；或（2）“外”，椎弓根螺钉的轴超出椎弓根的范围。
共研究了 553 个胸椎椎弓根螺钉（A 组，n=181；B 组，n=189；C 组，n=183），其中 64 个被评为“外”（内侧，35 个；外侧，29 个），总体突破率为 11.6%。当根据外科医生不断发展的经验对突破率进行分层时，突破率呈时间性下降（A 组，15.5%；B 组，10.6%；C 组，8.7%；P<.05）。突破率的下降反映在时间上内侧突破的减少（A 组，9.4%；B 组，5.8%；C 组，3.8%；P<.05）。尽管未达到统计学意义，但对于凹侧根尖螺钉也观察到类似的趋势（A 组，21.2%；B 组，16.2%；C 组，10.5%）。
在变形的脊柱中，胸椎椎弓根螺钉的总体植入准确性为 88.4%，无神经或内脏并发症。A 组的 1 例患者在术后第 2 天返回手术室，取出了一个无症状的左侧 T7 胸椎椎弓根螺钉，该螺钉紧贴主动脉。随着外科医生经验的增加，总体突破率下降，这主要反映在更少的内侧突破。
