Mroz Thomas E, Abdullah Kalil G, Steinmetz Michael P, Klineberg Eric O, Lieberman Isador H
Cleveland Clinic Lerner College of Medicine, Cleveland, OH 44195, USA.
J Spinal Disord Tech. 2011 Jun;24(4):264-7. doi: 10.1097/BSD.0b013e3181eed618.
In-vitro radiation exposure study.
To determine the radiation exposure to the eyes, extremities, and deep tissue during percutaneous pedicle screw placement.
Image-guided minimally invasive spinal surgery is typically performed with the use of fluoroscopy, exposing the surgeon and patient to ionizing radiation. The radiation dose to the surgeon has not been reported and risk to the surgeon performing this procedure over the long term is uncertain.
Percutaneous pedicle screws were placed in a cadaveric specimen from L2-S1 bilaterally using a cannulated pedicle screw system. Two fluoroscopes were used in the anteroposterior and lateral planes. The surgeon wore a thermolucent dosimeter ring on the right hand and badge over the left chest beneath the lead apron. Complete surgical time was recorded and a computed tomography scan was performed to assess screw placement. Radiation exposure was measured for total time of fluoroscopy use; average exposure per screw, surgical level, and dose to the eyes was calculated. This data was used to define the safety of percutaneous pedicle screw placement.
Total fluoroscope time for placement of 10 percutaneous pedicle screws was 4 minutes 56 seconds (29 s per screw). The protected dosimeter recorded less than the reportable dose. The ring dosimeter recorded 103 mREM, or 10.3 mREM per screw placed. All screws were within the bone confines with acceptable trajectory. Exposure to the eyes was 2.35 mREM per screw.
On the basis of this data, percutaneous pedicle screw placement seems to be safe. A surgeon would exceed occupational exposure limit for the eyes and extremities by placing 4854 and 6396 screws percutaneously, respectively. Lead protected against radiation exposure during screw placement. The "hands-off" technique used in this study is recommended to minimize radiation exposure. Lead aprons, thyroid shields, and leaded glasses are recommended for this procedure.
体外辐射暴露研究。
确定经皮椎弓根螺钉置入过程中眼睛、四肢和深部组织的辐射暴露情况。
图像引导下的微创脊柱手术通常使用荧光透视进行，使外科医生和患者暴露于电离辐射中。尚未有关于外科医生所受辐射剂量的报道，长期进行该手术的外科医生所面临的风险尚不确定。
使用空心椎弓根螺钉系统在一具尸体标本的双侧L2 - S1节段置入经皮椎弓根螺钉。在前后位和侧位平面使用两台荧光透视仪。外科医生右手佩戴热释光剂量计指环，在铅衣下左胸佩戴胸章。记录完整的手术时间，并进行计算机断层扫描以评估螺钉置入情况。测量荧光透视使用的总时间的辐射暴露；计算每颗螺钉、手术节段的平均暴露量以及眼睛所受剂量。这些数据用于确定经皮椎弓根螺钉置入的安全性。
置入10枚经皮椎弓根螺钉的荧光透视总时间为4分56秒（每颗螺钉29秒）。受保护剂量计记录的剂量低于可报告剂量。指环剂量计记录为103毫雷姆，即每置入一颗螺钉为10.3毫雷姆。所有螺钉均在骨边界内且轨迹可接受。每颗螺钉对眼睛的暴露量为2.35毫雷姆。
基于这些数据，经皮椎弓根螺钉置入似乎是安全的。外科医生分别经皮置入4854颗和6396颗螺钉时，才会超过眼睛和四肢的职业暴露限值。在螺钉置入过程中铅衣可防止辐射暴露。建议采用本研究中使用的“非接触”技术以尽量减少辐射暴露。对于该手术，建议使用铅衣、甲状腺防护装置和铅眼镜。
