骶髂螺钉置入S1椎弓根的形态学研究

目的研究S1椎弓根的形态学特点，探讨经骶髂关节置入S1椎弓根螺钉的可行性。方法测量16具尸体骨盆标本双侧S1椎弓根前后缘的高度、深度(S1椎弓根最狭窄处的宽度)、骶翼深度、骶翼高度。测量骨盆出口位X线片上S1椎弓根的高度，并与肉眼解剖比较。在轴位CT图像上测量髂骨后缘到骶翼、S1椎弓根、S1椎弓根纵轴的距离、髂骨外板与骶椎前缘皮质的距离。观察S1椎弓根矢状切面，评估置入2枚经S1椎弓根骶髂螺钉的安全区。结果椎弓根前后缘的高度平均为30．2mm、26．Imm，椎弓根深度和骶翼深度平均为27．8mm、45．8mm，骶翼后部平均高度为28．7mm。骨盆出口位X线片上S1椎弓根的平均高度是20mm，小于肉眼解剖测量结果(P＜0．0001)。轴位CT图像上，S1椎弓根纵轴在髂骨外板投影点到髂骨后缘的距离平均为32．5mm，到坐骨大切迹最高点的距离平均为38．6mm，髂骨外板到S1椎体前缘皮质的距离平均为105．2mm。结论置入1枚S1椎弓根螺钉是安全的，常规置入2枚椎弓根螺钉可能较困难。     

经S2椎弓根骶髂关节螺钉固定CT和解剖学研究

目的 :为经S2 椎弓根水平骶髂关节螺钉固定提供解剖学依据。方法 :对 2 2个骨盆标本进行解剖学研究 ,测量经S2 椎弓根骶髂关节螺钉固定的进针点、进针方向、钉道直径、进针点至S2 椎体中心和椎弓根中心距离、S2 椎弓根横断面形状。结果 :螺钉进针点在髂后下棘前方 2 8 7mm (15 0～34 5mm) ,坐骨切迹上方 15 3mm(10 0～ 2 2 0mm) ;进针方向垂直于正中矢状面且与髂骨翼外侧面夹角为 6 2 4°(5 5°～ 72°) ;钉道直径为 11 5mm (8 5～ 14 0mm) ;进针点至S2 椎体中心距离 6 4 7mm(5 5 3～ 77 6mm) ;进针点至S2 椎弓根中心距离为 5 3 1mm(45 3～ 6 4 8mm) ;S2 椎弓根横截面呈三角形。结论 :经S2 椎弓根水平骶髂关节螺钉固定的进针点应位于髂后下棘前方 30mm ,坐骨切迹上方15mm ;进针方向垂直于正中矢状面且与髂骨翼外侧面夹角为 6 0°;S2 椎弓根钉道直径较小 ,经S2 椎弓根水平骶髂关节螺钉固定应选择直径较小的短螺钉。     

骶髂关节经皮拉力螺钉固定钉道参数的解剖学测量

目的 为经S_1椎弓根水平骶髂关节拉力螺钉固定术提供应用解剖学依据.方法 2008年6月至2009年7月收集50个成人骨盆的螺旋CT扫描数据,重建骨盆三维模型,模拟经皮托力螺钉固定.测量S_1椎弓根的宽和高、骶髂关节拉力螺钉的进针点和进针方向、进针点至S_1椎体对侧前皮质和髂后上棘的距离.结果 S_1椎弓根的宽和高分别为(20.43±1.63)mm和(20.26±0.99)mm;2枚螺钉的进针点均在髂前上棘和髂后上棘的连线上方,至髂后上棘的距离分别为(49.87±6.80)mm和(51.11±7.15)mm.螺钉平行进入S_1椎弓根,与髂骨翼后外侧面垂直,与冠状面和欠状面的夹角分别为18.35°±5.20°和77.62°±3.98°.进针点到S1椎体对侧前皮质的距离分别为(76.08±4.32)mm和(77.62±3.98)mm.骶髂关节拉力螺钉的长度、S_1椎弓根的高度和宽度、进针点到髂后上棘的距离、进针点与冠状面的夹角在男女之间差异有统计学意义(P<0.05).结论 正常成人在S_1椎弓根水平均町置入2枚直径为6.5 mm的拉力螺钉,钉道参数的解剖学测量为骶髂关节拉力螺钉固定手术导航模板的设计提供了理论基础.     

经骶髂关节置入骶1椎弓根螺钉的解剖学和影像学测量

目的:通过S1椎弓根的解剖学和影像学测量,探讨经骶髂关节置入S1椎弓根螺钉的可行性。方法:测量16具尸体骨盆标本双侧S1椎弓根前后缘的高度、深度(S1椎弓根最狭窄处的宽度)、骶翼深度、骶翼高度。测量骨盆出口位X线片上S1椎弓根的高度,并与解剖学测量结果比较。在轴位CT上测量髂骨后缘到骶翼、S1椎弓根、S1椎弓根纵轴的距离、髂骨外板与骶椎前缘皮质的距离。观察S1椎弓根矢状切面,评估置入2枚经S1椎弓根骶髂螺钉的安全区。结果:S1椎弓根前、后缘的高度平均为30.2mm和26.1mm,椎弓根深度和骶翼深度平均为27.8mm和45.8mm,骶翼后部平均高度为28.7mm。骨盆出口位X线片上S1椎弓根的平均高度是20mm,小于解剖学测量结果(P<0.0001)。轴位CT上,S1椎弓根纵轴在髂骨外板投影点到髂骨后缘的距离平均为32.5mm,到坐骨大切迹最高点的距离平均为38.6mm,髂骨外板到S1椎体前缘皮质的距离平均为105.2mm。结论:置入1枚S1椎弓根螺钉是安全的,常规置入2枚椎弓根螺钉可能较困难。     

骶髂螺钉固定在骶髂关节脱位中的应用解剖学研究

目的 :为应用骶髂螺钉固定骶髂关节脱位提供形态学依据。方法 :对 3 0具成人干燥骨盆标本 ,模拟骶髂螺钉内固定手术并作CT扫描 ,对进针点与不同解剖结构之间的距离、进针的方向、进针的深度以及S1骶孔上方的骶骨翼的前后径和上下径进行测量。结果 :进针点距臀肌线的距离为 ( 2 0 70± 3 2 7)mm ,距坐骨大切迹的距离为( 3 5 0 0± 1 91)mm ;轴位及冠状位CT测量进针与髂骨外板的交角分别为 ( 90 18± 2 69)°和 ( 90 40± 2 87)° ;进针深度为 ( 67 77± 3 63 )mm ;S1骶孔上方骶骨翼的前后径和上下径分别为 ( 18 2 6± 2 0 6)mm和 ( 18 74± 1 5 1)mm。结论 :临床应用骶髂螺钉固定需选择恰当的进针点和进针方向 ,术中需行骨盆正位、入口位和出口位的透视以确定螺钉植入的准确性     

骨盆后环MRI图像参数测量及临床意义

目的 应用MRI图像测量骨盆后环相关参数,为仰卧位S1椎弓根水平骶髂置钉术提供解剖学依据.方法 测量骶髂关节角度,椎弓根有效长度、直径、高度,及直径7.2 mm螺钉在椎弓根内的活动范围.结果 S1椎弓根有效长度:(74.0±5.4)mm,直径:(14.4±2.3)mm;骶髂关节角度:(29.0±9.1)°.横断位S1椎弓根角度:(28.6±8.0)°,螺钉移动范围:(7.8±3.4)°-(41.6±5.7)°.冠状位S1椎弓根高度:(21.9±2.8)mm,角度:(21.3±4.6)°,螺钉移动范围:(7.6±1.1)°～(31.4±3.8)°.结论 经S1椎弓根置入1枚7.2 mm螺钉较为安全,置人2枚较为困难;向前20～30°,向足端倾斜5～15°,是仰卧位骶髂置钉术的安全途径.     

髂一髂拉力螺钉在骨盆后环损伤中应用的安全性研究

目的利用CT测量数据,为跨骶骨的髂一髂拉力螺钉技术在骨盆后环损伤中的应用提供理论依据。方法选取2008--2012年问在我院行骨盆cT检查的患者资料,男、女各60例,分别测量骨盆后环在髂后上棘水平双侧髂骨最佳进针点之间连线的距离以及该连线距离骶管后缘和髂后上棘高点的距离,通过SPSS14．0软件对数据进行分析,计量数据以（x±s）来表示,以获得最佳进针范围。结果髂后上棘高点距离最佳进针点连线的垂直距离男性为（1．66±0．358）cm,女性为（1．38±0．267）cm;最佳进针点连线距离骶管后缘的垂直距离男性为（0．76±0．204）cm,女性为（1．34±0．328）cm;髂后上棘水平在安全进针范围内双侧髂骨外板之间的距离的平均数值,男性为（11．56±0．652）cm,女性为（12．36±0．968）cm。结论跨骶骨的髂一髂拉力螺钉技术在骨盆后环损伤中的应用安全。     

加长骶髂螺钉固定相关参数的放射解剖学研究

[目的]通过测定S1、S2加长骶髂螺钉可置钉区域的相关指标,为加长骶髂螺钉固定的临床实践提供解剖学依据。[方法]对66名成人进行骨盆CT扫描,对S1、S2加长骶髂螺钉可置钉区域的长、宽、高进行测量,对进钉点作量化定位。对上述指标行统计学描述,并对左右两侧、S1、S2两节段、S1、S2各自不同层面的同种数值进行比较。[结果]模拟左右两侧置钉的相关测量所得同种数值无显著性差异;S1、S2加长骶髂螺钉安全置钉区域的髂骨长度均>16 mm;S1、S2可置钉区域的宽、高均>7.3 mm,且整体而言S1比S2具有更大的宽度值和高度值;加长骶髂螺钉最佳进钉点的量化定位参考范围,S1:髂后上棘前方42.21～63.69mm,坐骨大切迹最高点上方32.77～53.75mm。S2:髂后上棘前方22.68～54.28 mm,坐骨大切迹最高点上方14.06～33.70 mm。[结论](1)S1、S2加长骶髂螺钉的置入具有解剖学的可行性;(2)同一节段左右两侧置入加长骶髂螺钉的各项指标无差异;(3)螺纹长度为16mm的7.3 mm部分螺纹空心钉和6.5 mm部分螺纹松质骨螺钉均可作为加长骶髂拉力螺钉使用;(4)S1、S2均有置入至...     

椎弓根螺钉+髂骨螺钉系统固定治疗骨盆后环不稳

目的探讨椎弓根螺钉结合髂骨螺钉复位固定治疗骨盆后环不稳定的临床疗效。方法对12例骶髂关节骨折(脱位)患者采用后路椎弓根螺钉结合髂骨螺钉复位固定。结果患者骶髂关节均达到解剖复位,未发生血管、神经损伤等并发症。12例均获随访,时间6～16个月。骶髂关节均获融合。结论椎弓根螺钉结合髂骨螺钉固定对于骨盆后环不稳定骨折脱位有良好的复位固定作用,临床疗效良好。     

以S_1椎弓根为轴固定术治疗骨盆后环损伤

目的探讨以S1椎弓根为轴固定术治疗骨盆后环损伤的疗效。方法将2004年1月～2007年6月治疗资料完整54例骨盆后环损伤进行分析,侧方途径采用俯卧位、仰卧位及仰卧位CT引导下经皮置入1枚骶髂空心螺钉固定治疗骨盆后环损伤。后路途径在髂骨后部、一侧S1椎弓根及另一侧S1椎弓根或L5椎弓根各置入1枚多轴椎弓根螺钉,形成骶-髂或腰-骶-髂固定术,配合骨盆前方固定重建骨盆环稳定性。结果平均随访18个月,骨折均愈合。无明显盆部畸形、双下肢不等长和骶髂部疼痛。按Majeed功能评定标准,优良率92.6%(50/54)。结论根据患者病情和骨折类型,选择以S1椎弓根为轴固定术治疗骨盆后环损伤,可取得满意疗效。     

寰椎后弓-横突髓腔钉道的影像解剖学参数及其临床意义

目的通过影像归档和通信系统(PACS)测量成人寰椎后弓-横突髓腔钉道的解剖学参数,并结合临床病例探讨其临床意义。方法选择2016年1月—2017年6月本院PACS中18~70岁患者的颈椎三维CT数据,共200例,男女各100例,年龄(54.95±11.93)岁。选取寰椎后弓-横突髓腔最长轴切面为测量截面,利用PACS测量软件手工测量该截面入钉点与后结节距离、入钉角度与矢状面夹角、入钉角度与横截面夹角、钉道长度、椎动脉沟狭窄处髓腔高度和入钉点髓腔最大高度等解剖学参数,所得数据纳入统计学分析。结合临床病例探讨其可行性。结果入钉点与后结节距离为(7.45±1.75)mm,入钉角度与矢状面夹角为54.26°±6.06°,入钉角度与横截面夹角为9.15°±3.40°、钉道长度为(18.55±3.75)mm,椎动脉沟狭窄处髓腔高度为(2.09±0.81)mm,入钉点髓腔最大高度为(4.93±0.37)mm。男性寰椎后弓-横突髓腔钉道在入钉点与后结节距离、钉道长度、椎动脉沟狭窄处髓腔高度和入钉点髓腔最大高度均大于女性,差异有统计学意义(P0.05),不同性别之间入钉角度与矢状面夹角和入钉角度与横截面夹角差异无统计学意义(P0.05)。经有限病例初步证实该置钉方式具有可行性。结论寰椎后弓-横突髓腔的解剖学特点能够满足置钉要求,在常规寰椎椎弓根螺钉进钉点狭小无法置钉或钉道破裂置钉失败时,可以当做替代置钉钉道方案。     

Cervical pedicle screw fixation at C6 and C7: A cadaveric study

Background:Cervical pedicle screw fixation is an effective method for treating traumatic and non traumatic injuries. But many studies have reported higher incidence of cervical pedicle penetration, so many research efforts have aimed at improving the accuracy of cervical screw fixation. Most of the anatomical studies on cervical pedicle screw placement previously published focused on the measurements of anatomical parameters, the entry point of pedicle screw is vague. We preliminarily designed a C3, C4 and C5 pedicle screw fixation method that had clear entry point and clinical cases confirmed that this method is feasible and safe. So we did this study of cervical pedicle screw fixation for C6 and C7 vertebrae.Results:In C6, the PW and PH were 6.12 ± 0.78 and 7.48 ± 0.81 mm, respectively. In C7, the PW and PH were 6.85 ± 0.73 and 8.03 ± 0.38 mm, respectively. The LSC was 30.83 ± 0.91 mm. Two E angles were identified, namely E1 and E2 and their values were 89.61 ± 1.24 and 59.71 ± 1.10°, respectively. Meanwhile, F averaged 75.86 ± 1.12°.Conclusion:The intersection of the horizontal line through the midpoint of the transverse process root and vertical line through the intersection of the posterolateral and posterior planes of the isthmus can be used as an entry point for C6 and C7 pedicle screw fixation. The screws should be inserted at 60 or 90° with the posterolateral isthmus in the horizontal plane and at 75° with the posterior isthmus in the sagittal plane. The LSC should not exceed 30 mm.     

强直性脊柱炎伴胸腰椎后凸畸形腰椎及S1椎弓根的解剖特征及临床意义

目的:通过对强直性脊柱炎(ankylosing spondylitis,AS)伴胸腰椎后凸畸形和椎间盘退变性疾病(disc degenerative disease,DDD)患者L1-S1椎弓根CT扫描相关参数的测量,研究两者椎弓根解剖参数差异,为临床手术中置钉提供参考依据。方法:选取2012年3月至2014年11月行截骨矫形手术治疗并有完整术前临床及影像学资料的男性AS伴后凸畸形患者30例(AS组),年龄23~51岁,平均(35.7±9.5)岁,同时选取行手术治疗具有完整术前全腰椎及骶椎CT扫描全部附件结构影像清晰易辨的男性DDD患者30例(DDD组),年龄39~64岁,平均(52.4±8.9)岁。分别测量L1-S1节段椎弓根内聚角(pedicle transverse angle,EA),椎弓根矢状角(pedicle inclined angle,FA),椎弓根宽度(pedicle width,PW),椎弓根钉道长度(pedicle screw path length,PL),椎弓根高度(pedicle height,PH),统计比较是否存在差异。结果:AS组和DDD组椎弓根宽度(PW)自L1-S1均是逐渐增大的,AS组PW在L5、S1均显著大于DDD组,分别为(16.47±2.66)mm vs.(14.51±2.11)mm和(21.76±2.97)mm vs.(18.87±2.14)mm(P0.05);椎弓根钉道长度(PL)自L1-S1在AS组均大于DDD组(P0.05);PL两组最大值均在L3节段;AS组椎弓根内聚角(EA)在L1-S1均较DDD组小;AS矢状角(FA)在L3-S1显著小于DDD组(P0.05),分别为(-2.88±10.24)°,(-7.88±10.22)°,(-7.70±10.40)°,(-5.15±10.25)°vs.(4.05±2.21)°,(7.79±4.38)°,(7.07±3.21)°,(12.62±3.21)°。结论:在AS伴后凸畸形患者腰椎及S1椎弓根置钉时可选用更粗更长螺钉来增加内固定强度,需注意适当减小内聚角,并根据矢状面形态调整头尾向。     

Feasibility and accuracy of computer-assisted individual drill guide template for minimally invasive lumbar pedicle screw placement trajectory

ObjectiveTo discuss the feasibility and accuracy of a specific computer-assisted individual drill guide template (CIDGT) for minimally invasive lumbar pedicle screw placement trajectory (MI-LPT) through a bovine cadaveric experimental study.DesignA 3-D reconstruction model, including lumbar vertebras (L1–L5), was generated, and the optimal MI-LPTs were determined. A drill guide template with a surface made of the antitemplate of the vertebral surface, including the spinous process and the entry point vertebral surface, was created by reverse engineering and rapid prototyping techniques. Then, MI-LPTs were determined by the drill guide templates, and the trajectories made by K-wires were observed by postoperative CT scan.SettingGeneral Hospital of Shenyang Military Area Command of Chinese PLA.ResultsIn total, 150 K-wires for MI-LPTs were successfully inserted into L1-L5. The required mean time and fluoroscopy times between fixation of the template to the spinous process, entry point vertebral surface, and insertion of the K-wires for minimally invasive lumbar pedicle screw placement trajectories into each vertebra were 79.4 ± 15.0 s and 2.1 ± 0.8 times. There were no significant differences between the preoperative plan and postoperative assessment in the distance from the puncture to the midline and inclination angles according to the different levels (P > 0.05, respectively). The mean deviation between the preoperative plan and postoperative assessment in the distance from the puncture to the midline and inclination angles were 0.8 ± 0.5 mm and 0.9 ± 0.5°, respectively.ConclusionsThe potential use of the novel CIDGT, which was based on the unique morphology of the lumbar vertebra to place minimally invasive lumbar pedicle screws, is promising and could prevent too much radiation exposure intraoperatively.     

基于磁共振神经显像技术解剖学研究的TLIF操作安全性分析

 目的 通过磁共振神经显像技术(magnetic resonance neurography, MRN)测量腰骶神经根及毗邻结构相关解剖参数,分析腰椎各节段经椎间孔腰椎体间融合术(transforaminal lumbar interbody fusion,TLIF)的安全性。方法 选取12名(男、女各6名)正常健康志愿者,采用3.0 T磁共振成像仪行腰骶神经根扫描,通过Osirix软件进行三维成像并测量神经根与上位椎弓根间距,神经根与下位椎弓根间距,神经根与矢状面夹角,上、下相邻椎弓根间距,上、下相邻神经根间距。结果 12名志愿者L₁～L₅神经根通过MRN技术均获得良好显像。L₁～L₅神经根与上位椎弓根间距、神经根与矢状面夹角呈逐渐变小趋势;而神经根与下位椎弓根间距,上、下相邻椎弓根间距则变化规律不明显。与TLIF术中操作空间密切相关的神经根与下位椎弓根间距男、女分别为(8.99±0.88) mm ~(10.72±1.01)mm和(7.76±0.46) mm～(8.54±0.65) mm,大多数受试者各节段均< 10mm,且女性数据明显小于男性。同节段左、右侧的差异无统计学意义。结论 根据以上解剖学测量,进行TLIF操作时对上位神经根具有一定骚扰,对某些患者存在一定的损伤风险。     

Location of the tibial tunnel aperture affects extrusion of the lateral meniscus following reconstruction of the anterior cruciate ligament

The anterior root of the lateral meniscus provides functional stability to the meniscus. In this study, we evaluated the relationship between the position of the tibial tunnel and extrusion of the lateral meniscus after anterior cruciate ligament reconstruction, where extrusion provides a proxy measure of injury to the anterior root. The relationship between extrusion and tibial tunnel location was retrospectively evaluated from computed tomography and magnetic resonance images of 26 reconstructed knees, contributed by 25 patients aged 17–31 years. A measurement grid was used to localize the position of the tibial tunnel based on anatomical landmarks identified from the three‐dimensional reconstruction of axial computed tomography images of the tibial plateaus. The reference point‐to‐tibial tunnel distance (mm) was defined as the distance from the midpoint of the lateral edge of the grid to the posterolateral aspect of the tunnel aperture. The optimal cutoff of this distance to minimize post‐operative extrusion was identified using receiver operating curve analysis. Extrusion of the lateral meniscus was positively correlated to the reference point‐to‐tibial tunnel distance (r ² = 0.64; p < 0.001), with a cutoff distance of 5 mm having a sensitivity to extrusion of 83% and specificity of 93%. The mean extrusion for a distance >5 mm was 0.40 ± 0.43 mm, compared to 1.40 ± 0.51 mm for a distance ≤5 mm (p < 0.001). Therefore, a posterolateral location of the tibial tunnel aperture within the footprint of the anterior cruciate ligament decreases the reference point‐to‐tibial tunnel distance and increases extrusion of the lateral meniscus post‐reconstruction. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1625–1633, 2017.

     

儿童S2髂骨螺钉置钉可行性分析及钉道规划

目的:利用计算机三维重建及模拟置钉技术评估S₂髂骨螺钉在国人儿童应用可行性,且优化测量其钉道参数。方法:选取2018年12月至2020年12月行骨盆CT扫描且年龄5~16岁的儿童骨盆影像学资料83例,排除骨折、畸形、肿瘤等情况,其中男44例,女39例,年龄(10.66±3.52)岁,依据年龄分为4组(A组5~7岁;B组8~10岁;C组11~13岁;D组14~16岁)。将获得的原始CT数据导入Mimics软件中,三维重建骨盆骨性结构,并在三维视图模拟分别以螺钉最大头倾角、最小头倾角置入直径6.5 mm S₂髂骨螺钉。随后在3-Matic软件中分别测量最大头倾角和最小头倾角下螺钉冠状位夹角、矢状位尾倾角、横断位外展角、置钉总长度、骶骨内螺钉长度、髂骨宽度、进钉点距皮肤距离。比较分析不同年龄段儿童S₂髂骨螺钉置钉参数间的差异及性别与左右侧别间差异。结果:83例儿童均可置入直径6.5 mm S₂髂骨螺钉。各置钉参数左右侧别间比较,差异无统计学意义(P>0.05)。5~7岁儿童螺钉冠状位角度小于其他年龄段(P<0.05);但在螺钉矢状位角度上,在螺钉最大头倾角下5~7岁儿童可获得较大角度,但在最小头倾角下较大角度获得年龄组为11~13岁。螺钉横断位角度各年龄组差异无统计学意义(P>0.05)。5~7岁男童在最大头角下的冠状位角度和最小头倾角下的矢状位角度均大于女童(P<0.05);8~10岁女童最小头倾角下的冠状位角度大于男童(P<0.05);其余置钉角度参数男女性别间差异均无统计学意义(P>0.05)。各年龄组间,髂骨最小宽度、最长钉道距离及骶骨内螺钉长度差异随年龄增长,均呈增长趋势(P<0.05)。5~7岁及8~10岁女童皮肤距离均大于男性(P<0.05)。男童在14~16岁髂骨最小宽度宽于同阶段女童(P<0.05)。而5~7岁及11~13岁女童,最长钉道距离长于同阶段男童(P<0.05)。结论:5~16岁儿童骨盆可安全容纳直径6.5 mm S₂髂骨螺钉置入,但是由于儿童骨盆骨性结构处于发育生长时期,需精准评估,规划合理钉道、选择合适螺钉长度。     

Proposed alternative revision strategy for broken S1 pedicle screw: radiological study,review of the literature,and case reports

Background contextThere have been many reports outlining differing methods for managing a broken S1 screw. To the authors' best knowledge, the technique used in the present study has not been described previously. It involves insertion of a second pedicle screw without removing the broken screw shaft.Study designRadiological study, literature review, and two case reports of the surgical technique.PurposeTo report a proposed new surgical technique for management of broken S1 pedicle screws.MethodsComputed tomography (CT) scans of 50 patients with a total of 100 S1 pedicles were analyzed. There were 25 male and 25 female patients with an average age of 51 years ranging from 36 to 68 years. The cephalad-caudal length, medial-lateral width, and cross-sectional area of the S1 pedicle were measured and compared with the diameter of a pedicle screw to illustrate the possibility of inserting a second screw in S1 pedicle without removal of the broken screw shaft. Two case reports of the proposed technique are presented.ResultsThe left and right S1 pedicle cross-sectional area in female measured 456.00±4.00 and 457.00±3.00 mm², respectively. The left and right S1 pedicle cross-section area in male measured 638.00±2.00 and 639.00±1.00 mm², respectively. There were statistically significant differences when comparing male and female S1 pedicle length, width, and cross-sectional area (p<.05). At 2-year follow-up, the two case reports of the proposed technique showed resolution of low back pain and radicular pain. Plain radiograph and CT scan showed posterolateral fusion mass and hardware in good position with no evidence of screw loosening.ConclusionsThe S1 pedicle dimensions measured on CT scan reviewed in the present study showed that it may be anatomically feasible to place a second screw through the S1 pedicle without the removal of the broken screw shaft. This treatment method will reduce the complications associated with other described revision strategies for broken S1 screws.