Martus Jeffrey E, Hilmes Melissa A, Grice Jared V, Stutz Christopher M, Schoenecker Jonathan G, Lovejoy Steven A, Mencio Gregory A
Division of Pediatric Orthopaedics.
Division of Pediatric Radiology, Monroe Carell Jr Children's Hospital at Vanderbilt.
J Pediatr Orthop. 2018 May/Jun;38(5):249-253. doi: 10.1097/BPO.0000000000000810.
Factors that impact radiation exposure during operative fixation of pediatric supracondylar humerus (SCH) fractures have been investigated; however, no studies have measured the equivalent dose at the patient's radiosensitive organs. Our hypothesis was that intraoperative fluoroscopy exposes pediatric patients to a significant radiation load and lead shielding of radiosensitive organs is important. The goal of the study was to quantify the patient's radiation exposure during the procedure by measuring the radiation load at the thyroid and gonads.
A prospective quality improvement project of radiation exposure during percutaneous fixation of isolated SCH fractures was performed over a 4-week period. The c-arm image intensifier was used as the operating table and radiation dosimeters were positioned over the thyroid and gonadal lead shields. Fluoroscopy times were recorded, doses were calculated, and the dosimeters were analyzed. To assure that the prospective cohort was representative of a larger population of SCH fractures, demographics and fluoroscopy time of the prospective cohort were compared with a 12-month retrospective cohort in which dosimetry was not performed.
Prospective cohort-18 patients with type 2 (8) and type 3 (10) fractures were prospectively studied with intraoperative measurement of thyroid and gonadal radiation equivalent doses. Mean age was 4.9 years (1.9 to 9.5 y) and mean weight was 21.4 kg (13.1 to 33.5 kg). Mean fluoroscopy time was 65.0 seconds (25.3 to 168.4 s), and absorbed skin dose at the elbow was 0.47 mGy (0.18 to 1.21 mGy). The radiation dosimeters overlying the thyroid and gonads measured minimal radiation indicating equivalent doses of <0.01 mSv for all patients in the prospective cohort.Retrospective cohort-163 patients with type 2 (60) and type 3 (103) fractures were retrospectively studied. The mean age was 5.5 years (0.02 to 13.7 y) and weight was 21.6 kg (2.0 to 71.9 kg). Mean fluoroscopy time was 74.1 seconds (10.2 to 288.9 s), and absorbed skin dose at the elbow was 0.53 mGy (0.07 to 2.07 mGy).There were no statistically significant differences between the cohorts.
The smaller prospective cohort had fluoroscopy times and radiation doses that were not statistically different from the larger retrospective cohort, suggesting that the dosimeter measurements are representative of intraoperative radiation exposure during fixation of pediatric SCH fractures. The equivalent dose to the thyroid and gonads was minimal and approximates daily background radiation. Shielding of radiosensitive organs is appropriate when practical to minimize cumulative lifetime radiation exposure, particularly in smaller patients and when longer fluoroscopy times are anticipated.
Level 2.
影响小儿肱骨髁上骨折（SCH）手术固定期间辐射暴露的因素已得到研究；然而，尚无研究测量患者放射敏感器官处的当量剂量。我们的假设是术中透视会使小儿患者承受显著的辐射负荷，对放射敏感器官进行铅屏蔽很重要。本研究的目的是通过测量甲状腺和性腺处的辐射负荷来量化手术过程中患者的辐射暴露。
在4周期间对孤立性SCH骨折经皮固定时的辐射暴露开展了一项前瞻性质量改进项目。使用C形臂影像增强器作为手术台，并将辐射剂量计置于甲状腺和性腺铅屏蔽上方。记录透视时间，计算剂量，并对剂量计进行分析。为确保前瞻性队列能代表更多的SCH骨折患者群体，将前瞻性队列的人口统计学数据和透视时间与一个未进行剂量测定的12个月回顾性队列进行了比较。
前瞻性队列——对18例2型（8例）和3型（10例）骨折患者进行了前瞻性研究，术中测量了甲状腺和性腺的辐射当量剂量。平均年龄为4.9岁（1.9至9.5岁），平均体重为21.4千克（13.1至33.5千克）。平均透视时间为65.0秒（25.3至168.4秒），肘部皮肤吸收剂量为0.47毫戈瑞（0.18至1.21毫戈瑞）。置于甲状腺和性腺上方的辐射剂量计测量到的辐射极小，表明前瞻性队列中所有患者的当量剂量均<0.01毫希沃特。回顾性队列——对163例2型（60例）和3型（103例）骨折患者进行了回顾性研究。平均年龄为5.5岁（0.02至13.7岁），体重为21.6千克（2.0至71.9千克）。平均透视时间为74.1秒（10.2至288.9秒），肘部皮肤吸收剂量为0.53毫戈瑞（0.07至2.07毫戈瑞）。两个队列之间无统计学显著差异。
较小的前瞻性队列的透视时间和辐射剂量与较大的回顾性队列无统计学差异，这表明剂量计测量结果可代表小儿SCH骨折固定术中的辐射暴露情况。甲状腺和性腺的当量剂量极小，接近每日本底辐射。在可行时，对放射敏感器官进行屏蔽以尽量减少终生累积辐射暴露是合适的，尤其是对于较小的患者以及预期透视时间较长时。
2级。
