探讨伽马刀立体定向放射外科（SRS）如何选择合适长度的头架固定螺钉。

选取2013年1月至2019年11月西安长安医院肿瘤科治疗的535例脑疾病患者作为研究对象。每例患者均需采集左前额、右前额、左后枕、右后枕的颅骨外板厚度以及头皮+颅骨外板厚度2组数据，这样每人可获取4组常用螺钉植入点的8个数据，各位点所测数据命名规则为R_额皮、R_额板、L_额皮、L_额板、L_枕皮、L_枕板、R_枕皮、R_枕板。分别比较左右额皮、额板、枕皮、枕板，及同侧额皮与枕皮各位点厚度的差异，并进行性别及年龄分层分析。

各螺钉植入点厚度分别为：R_额皮=（0.733±0.139）cm，R_额板=（0.337±0.087）cm；L_额皮=（0.719±0.152）cm，L_额板=（0.318±0.079）cm；L_枕皮=（1.069±0.208）cm，L_枕板=（0.364±0.068）cm；R_枕皮=（1.085±0.212）cm，R_枕板=（0.341±0.058）cm。各配对螺钉植入点厚度比较：左右额皮、左右枕皮分别比较差异均无统计学意义（P>0.05）；左右额板、左右枕板、左额皮与左枕皮、右额皮与右枕皮比较差异均具有统计学意义（P<0.05）。男女不同性别之间以及>60岁与≤60岁年龄组之间差异均无统计学意义（P>0.05）。

对于拟行伽马刀SRS头架螺钉固定治疗的患者，如选用表皮进钉建议参考左右前额进皮长度0.8 cm左右，后枕进皮长度1.1 cm左右；如果选用透皮从外板进钉建议参考四个位点进板深度均≤0.3 cm；该方案也更加符合个体化原则。

To solve the problem of how to choose the appropriate screw for stereotaxic radio surgery (SRS).

Five hundred and thirty-five patients with brain diseases, admitted to Oncology Department of Xi’an Chang’an Hospital from January 2013 to November 2019 were selected. Each patient needs to collect two sets of data at four fixed points data of the thickness of the plating and the scalp. Eight data were obtained for each patient, the naming rules of the measured data at each site are R_{forehead-scrap}, R_{forehead-plate}, L_{forehead-scrap}, L_{forehead-plate}, L_{occipital-scrap}, L_{occipital-plate}, R_{occipital-scrap}, and R_{occipital-plate}. The difference of the left and right forehead scrap and left and right foreheads, left and right occipital scraps and left and right occipital plates were compared, and whether there is a difference between the same forehead scrap and occipital scrap.

The mean and standard deviation of the thickness of each screw point were: R_{forehead-scrap}=(0.733±0.139)cm, R_{forehead-plate}=(0.337±0.087)cm; L_{forehead-scrap}=(0.719±0.152)cm, L_{forehead-plate}=(0.318±0.079)cm; L_{occipital-scrap}=(1.069±0.208)cm, L_{occipital-plate}=(0.364±0.068)cm; R_{occipital-scrap}=(1.085±0.212)cm, R_{occipital-plate}=(0.341±0.058)cm. There was no significant difference in the left and right forehead scrap, and left and right occipital scrap (P>0.05). There was significant difference in the thickness of the left and right frontal skin, left and right occipital skin, left frontal skin and left occipital skin, right frontal skin and right occipital skin (P<0.05). There was no significant difference between men and women of different genders, and between the groups of >60 years old and ≤60 years old (P>0.05).

For patients treated with gamma knife SRS, implanting screws from the scalp: the forehead length is about 0.8 cm, and the occipital lengh is about 1.1 cm. Implanting screws from the plate the nail length is recommended to be ≤0.3 cm, the scheme is more in line with the individuation principle.