经骶髂关节置入S1椎弓根螺钉的数字解剖学研究

目的 利用数字技术对骨盆后环结构进行解剖学测量,为经骶髂关节置入S1椎弓根螺钉固定提供临床解剖学依据. 方法 收集2008年1月至2011年12月期间共68例成人骨盆(136个半骨盆)的16排螺旋CT扫描数据,利用Mimics 10.01软件重建骨盆三维模型,模拟骶髂螺钉内固定.利用软件自带测量工具测量S1椎弓根宽度、高度、进钉点的位置、进钉方向,以及螺钉的长度和直径,并比较男女性、左右侧及 ＜50岁年龄组与≥50岁年龄组间上述指标的差异. 结果 S1椎弓根宽度、高度平均分别为(21.17±2.69)、(23.65 ±2.70) mm.螺钉进钉点、位于髂后上棘和髂前上棘连线前3/4或后1/4点的上方平均(10.90±5.14) mm处,螺钉在冠状面的夹角平均为32.74°±6.34°,螺钉在矢状面的夹角平均为57.08°±6.11°,螺钉长度平均为(75.92±6.82) mm.左、右侧上述测量指标比较差异均无统计学意义(P＞0.05).男、女性之间螺钉在冠状面、矢状面的夹角比较差异无统计学意义(P＞0.05),其余指标比较差异均有统计学意义(P＜0.05);＜50岁年龄组和≥50岁年龄组螺钉进钉点位置及螺钉长度比较差异有统计学意义(P＜0.05),其余指标比较差异均无统计学意义(P＞0.05).结论 本研究测得的S1椎弓根螺钉进钉点位置、螺钉长度及方向等可作为临床于术的参考依据.男女性之间、不同年龄组间上述指标存在一定差异,临床工作中需实行个体化置钉方案.     

水平方向骶髂关节螺钉固定治疗骶骨纵形骨折的安全性评价

目的探讨水平方向骶髂关节螺钉固定治疗骶骨纵形骨折的安全性。 方法收集2009年9月至12月期间100例不伴骨性疾病的骨盆CT容积性数据,男52例,女48例;平均年龄43.1岁（15 ～91岁）。重建三维模型,获得标准骶骨矢状面。在各个矢状层面标记骨皮质的外缘,从而确定手术的安全区,水平方向模拟置入1枚安全区所能容纳的最大螺钉,记录其直径。根据螺钉固定方式不同,分为单侧固定和贯穿固定。结果根据骶骨形态学评价标准,形态正常80例,变异20例,变异率为20.0％。单侧固定时螺钉直径：变异组S2[(14.92±2.57) mm]＞正常组S2[(12.37±1.84)rm] (P=0. 000)＞正常组S1[(11.87±3.92) mm] (P=0.319)＞变异组S3[(9.30±2.00) mm](P=0.000)。贯穿固定时螺钉直径：变异组S2[(13.63±2.68) mm]＞正常组S2[(11.48±1.92) mm](P=0.002)＞正常组S1[(10.40±4.05) mm](P=0.033)＞变异组S3[(7.95±2.26)mm](P=0.001)。正常组S2所能容纳螺钉最大直径与S1呈弱负相关,而各骶椎所能容纳螺钉最大直径与髋臼直径无相关。男性S2椎体所能容纳螺钉的平均直径大于女性,差异有统计学意义(P＜0.05),S1椎体在性别间差异无统计学意义（P＞ 0.05）。结论绝大多数中国人可以在骨盆后环以水平方向固定2枚直径为6.5 mm的骶髂关节螺钉,但安全区较小。螺钉的入点、规格及所固定椎体[S1椎体和（或）S2椎体]必须严格按照影像学表现进行选择。骶骨变异并不是骶髂关节螺钉固定术的禁忌证。     

肠道准备对经皮横向骶髂关节螺钉固定的影响

[目的]探讨肠道准备对经皮横向骶髂螺钉固定的影响。[方法]2015年8月~2018年12月,30例骶骨骨折行经皮横向S1骶髂关节螺钉置入治疗的患者纳入本研究,采用随机数字表法将患者分为两组,每组15例,准备组患者术前接受肠道准备,无准备组患者术前未接受肠道准备。比较两组手术时间、术中透视次数和曝光时间,以及影像测量的置钉偏差。[结果]准备组的手术时间显著短于无准备组,差异有统计学意义[(32.31±4.92)min vs(40.54±5.83)min,P<0.05)];准备组的术中X线暴露时间显著短于无准备组,差异有统计学意义[(62.59±5.79)s vs(83.19±6.41)s,P<0.05];准备组的术中透视次数显著少于无准备组,差异有统计学意义[(3.71±0.58)次vs(5.21±1.11)次,P<0.05]。术后CT三维重建测量螺钉与术前测量偏移方面,准备组的水平偏移小于无准备组,但差异无统计学意义[(5.53±2.21)°vs(5.63±1.97)°,P>0.05];准备组矢状位偏移小于无准备组,但差异无统计学意义[(4.32±2.08)°vs(4.52±1.91)°,P>0.05]。术后随访6~12个月,所有患者均未发生骶髂关节螺钉松动及断裂等并发症。[结论]肠道准备虽不能提高置钉准确率,但能够缩短手术时间和术中X线暴露时间。     

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     

Triangular osteosynthesis and iliosacral screw fixation for unstable sacral fractures: a cadaveric and biomechanical evaluation under cyclic loads

OBJECTIVE: To conduct a biomechanical comparison of a new triangular osteosynthesis and the standard iliosacral screw osteosynthesis for unstable transforaminal sacral fractures in the immediate postoperative situation as well as in the early postoperative weight-bearing period. DESIGN: Twelve preserved human cadaveric lumbopelvic specimens were cyclicly tested in a single-limb-stance model. A transforaminal sacral fracture combined with ipsilateral superior and inferior pubic rami fractures were created and stabilized. Loads simulating muscle forces and body weight were applied. Fracture site displacement in three dimensions was evaluated using an electromagnetic motion sensor system. INTERVENTION: Specimens were randomly assigned to either an iliosacral and superior pubic ramus screw fixation or to a triangular osteosynthesis consisting of lumbopelvic stabilization (between L5 pedicle and posterior ilium) combined with iliosacral and superior pubic ramus screw fixation. MAIN OUTCOME MEASURES: Peak loaded displacement at the fracture site was measured for assessment of initial stability. Macroscopic fracture behavior through 10,000 cycles of loading, simulating the early postoperative weight-bearing period, was classified into type 1 with minimal motion at the fracture site, type 2 with complete displacement of the inferior pubic ramus, or type 3 with catastrophic failure. RESULTS: The triangular osteosynthesis had a statistically significantly smaller displacement under initial peak loads (mean +/- standard deviation [SD], 0.163 +/- 0.073 cm) and therefore greater initial stability than specimens with the standard iliosacral screw fixation (mean +/- SD, 0.611 +/- 0.453 cm) ( = 0.0104), independent of specimen age or sex. All specimens with the triangular osteosynthesis demonstrated type 1 fracture behavior, whereas iliosacral screw fixation resulted in one type 1, two type 2, and three type 3 fracture behaviors before or at 10,000 cycles of loading. CONCLUSION: Triangular osteosynthesis for unstable transforaminal sacral fractures provides significantly greater stability than iliosacral screw fixation under in vitro cyclic loading conditions. In vitro cyclic loading, as a limited simulation of early stages of patient mobilization in the postoperative period, allows for a time-dependent evaluation of any fracture fixation system.     

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。     

Investigation of bone quality of the first and second sacral segments amongst trauma patients: concerns about iliosacral screw fixation

Background

Iliosacral screw fixation has become a common method for surgical stabilization of acute disruptions of the pelvic ring. Placement of iliosacral screws into the first sacral (S1) body is the preferred method of fixation, but size limitations and sacral dysmorphism may preclude S1 fixation. In these clinical situations, fixation into the second sacral (S2) body has been recommended. The objective of this study was to evaluate the bone quality of the S1 compared to S2 in the described “safe zone” of iliosacral screw fixation in trauma patients.

Materials and methods

The pelvic computed tomography scans of 25 consecutive trauma patients, ages 18–49, at a level 1 trauma center were prospectively analyzed. Hounsfield units, a standardized computed tomography attenuation coefficient, was utilized to measure regional cancellous bone mineral density of the S1 and S2. No change in the clinical protocol or treatment occurred as a consequence of inclusion in this study.

Results

A statically significant difference in bone quality was found when comparing the first and second sacral segment (p = 0.0001). Age, gender, or smoking status did not independently affect bone quality.

Conclusion

In relatively young, otherwise healthy trauma patients there is a statistically significant difference in the bone density of the first sacral segment compared to the second sacral segment. This study highlights the need for future biomechanical studies to investigate whether this difference is clinically relevant. Due to the relative osteopenia in the second sacral segment, which may impact the quality of fixation, we feel this technique should be used with caution.

Level of evidence

III     

Pseudoaneurysm of the superior gluteal artery during iliosacral screw fixation

We present a case of a pseudoaneurysm of the superior gluteal artery following placement of an iliosacral screw in a patient with an unstable pelvic ring fracture. Percutaneous fixation of posterior pelvic ring injuries is becoming a popular method for pelvic stabilization. Several techniques are available t achieve stability and allow early mobilization in patients with displaced pelvic fractures. Percutaneous screw fixation of sacral fractures or sacroiliac joint disruptions should reduce operative and anaesthesia times as well as blood loss, while lowering the risk of surgical wound problems are decreased. The risks with this technique are generally iatrogenic, related with surgeon's lack of experience or imaging difficulties at the time of screw placement. The present case report describes an injury to the superior gluteal arterial system during percutaneous iliosacral screw insertion.     

The invention of an iliosacral screw fixation guide and its preliminary clinical application

Objective: To introduce an iliosacral screw fixation guide and evaluate its efficacy in fixation of sacroiliac joint fracture‐dislocations. Methods: Between January 2011 and May 2011, eight patients (five men, three women) with sacroiliac joint fracture‐dislocation underwent percutaneous iliosacral screw fixation with the assistance of this minimally invasive guide and under CT guidance. The patients, aged from 26 to 56 years (mean 32 years), had vertically unstable pelvic fractures. Before surgery, six patients who had displacement of >2 cm in their sacroiliac joints underwent skeletal traction on the femoral condyle. The inserted sites were marked out on the affected side of their buttocks after the best screw trajectory had been determined under CT control. The gear that controls the direction of the minimally invasive guide was adjusted according to the inserting angle determined by CT scans. A K‐wire was inserted into the sacroiliac joint along the pilot sleeve of the guide, and a hollow screw (diameter 7.3 mm) was implanted into the sacroiliac joint along the K‐wire. Results: All eight operations were successful on the first attempt. The operations lasted from 10 to 20 minutes (mean 14 minutes). Immediate CT scans confirmed that all the screws had been placed in the desired positions, none had penetrated the bones and the configuration of the sacroiliac joints had been satisfactorily restored and firmly fixed. No patient experienced numbness or radiating pain in the lower limbs during surgery. There were no postoperative vascular or neurological complications. Conclusion: The minimally invasive guide can eliminate discrepancies resulting from the surgeon's own sensory input when inserting screws under the guidance of CT, making percutaneous iliosacral screw fixation more accurate, safe and simple.     

四种骶骨钉固定技术的生物力学比较

目的通过骨质疏松骶骨标本对4种骶骨椎弓根钉（双皮质、三皮质、标准骨水泥强化和终板下骨水泥强化）载荷后的下沉位移进行比较。方法取自11具新鲜骨质疏松尸体的骶骨标本用于实验。采用DEXA测定骨密度后在同一骶骨的左右侧随机置入直径7mm的双皮质和三皮质骶骨椎弓根钉。使用MTS试验机对螺钉进行30～250N压力加载2000次后取出螺钉。钉道内注入骨水泥（polymethylmethacrylate,PMMA）,将比双皮质或三皮质固定短5mm的螺钉再次置人（分别定义为标准和终板下PMMA强化）,并重复上述加载。记录加载后螺钉的下沉位移,进行比较。结果11具标本的骨密度为0．55～0．78g／cm^2,平均0．7lg／cm^2。三皮质和标准PMMA强化椎弓根钉间的下沉位移差异无统计学意义,此2种固定技术的下沉位移显著低于双皮质固定。终板下PMMA强化椎弓根钉的下沉位移显著低于其他固定技术。结论在骨质疏松状态下PMMA强化可显著提高骶骨钉一骨界面的结合强度。在上述4种骶骨固定技术中终板下PMMA强化椎弓根钉可获得最坚强的锚定。     

骶髂关节空心钉内固定导向器的研制及临床应用

目的 自行设计并研制一种骶骼关节空心钉内固定导向器,以期提高S1椎弓根空心钉置入的成功率及置入质量。方法 自行设计并研制的骶髂关节空心钉内固定导向器由带有测量长度的定位器、带有角度刻度表的水平面S1椎弓根空心钉置入角（TSA）、矢状面置入角(SSA)调节器及固定螺丝等组成。2006年6月至2009年10月共收治15例不稳定型骨盆骨折累及骶髂关节者,男6例,女9例;年龄19 ～ 60岁,平均45.6岁。不稳定型骨盆骨折经骶髂关节韧带3例,经骶骨Ⅰ区5例,累及骶骨Ⅱ区5例,累及骶骨Ⅲ区2例。15例患者均采用骶髂关节空心钉内固定导向器引导术中空心钉的操作,共置入18枚空心钉。结果 术后CT及X线片示18枚空心钉置入位置准确,与术前设计相比,具有相同或相近的TSA及SSA。结论 骶骼关节空心钉内固定导向器设计合理,使用方便,能提高S1椎弓根空心钉置入的准确性及置入质量,且可显著减少C型臂X线机的透视次数。     

CT引导下微创导向器在经皮骶髂关节螺钉固定中的初步应用

 目的 探讨CT引导下微创导向器辅助经皮骶髂关节螺钉固定的准确性。方法 2011年 1月至 5月, 采用 CT引导下微创导向器辅助经皮骶髂关节螺钉固定治疗骶髂关节骨折脱位患者 8例, 男 5例, 女 3例;年龄 26~56岁, 平均 32岁;均为垂直不稳定骨盆骨折。术前对 6例骶髂关节移位超过 2 cm的患者行股骨髁上骨牵引, 牵引重量为体重的 1/8~1/7。在 CT操作台的计算机屏幕上进行定位、测量最佳进针轨道后, 在患侧臀部标记定位。根据 CT扫描确定的进针角度调节导向器角度, 沿导向器前 端套筒打入克氏针, 并顺克氏针拧入 7.3 mm的空心螺钉。结果 8例患者均一次操作成功。手术时间 10~20 min, 平均 14 min。术后即刻行 CT扫描, 确认所有螺钉均位于术前预计的位置并完全位于骨内无 穿出, 骶髂关节形态恢复满意并得到确切固定。所有患者术中均未诉患侧下肢麻木或放射样疼痛, 术后患肢无一例发生血管、神经并发症。结论 导向器可避免 CT引导下骶髂关节螺钉固定时术者仅凭感觉判断进针角度而造成的偏差, 提高了CT引导下骶髂关节螺钉置入的准确性、安全性和简便性。     

Loosening of sacral screw fixation under in vitro fatigue loading.

Sacral screw fixation is frequently used for fusion of the lower lumbar spine, but sacral screws appear to offer less secure fixation than lumbar pedicle screws, and failure due to loosening under fatigue loading is common. The aim of this study was to examine in vitro the stability of medial and lateral bicortical and unicortical sacral screw fixation under a physiologically relevant fatigue-loading pattern. Bone mineral density, screw insertion torque, and screw-fixation stiffness were measured prior to cyclic loading between 40 and 400 N compression at 2 Hz for 20,000 cycles. The screw-fixation stiffness was measured every 500 cycles, and the axial pullout strength of the screws was recorded following loading. All of the lateral insertions loosened under the applied loading, but some of the medial insertions remained stable. Medial insertions proved stiffer and stronger than lateral insertions, and bicortical fixations were stronger than unicortical fixations. Bone mineral density and insertion torque were correlated with screw stiffness and pullout strength, although better correlation was found for insertion torque than bone mineral density. Bone mineral density is a good preoperative indicator of sacral screw-fixation strength, and insertion torque is a good intraoperative indicator. An insertion torque greater than 1.5 Nm is suggested as an indicative value for a stable medial unicortical insertion, whereas an insertion torque greater than 2 Nm suggests a stable medial bicortical insertion. It appears that, apart from the choice of technique (screw orientation and depth), minimizing the load on the screws during the initial part of the fusion process is also critical to maintain stability of the fused section and to obtain a solid fusion mass.     

骶髂关节空心钉内固定导向器的研制及临床应用

目的自行设计并研制一种骶骼关节空心钉内固定导向器,以期提高S．椎弓根空心钉置入的成功率及置入质量。方法自行设计并研制的骶髂关节空心钉内固定导向器由带有测长度的定位器、带有角度刻度表的水平面S1椎弓根空心钉置入角（TSA）、矢状面置入角（SSA）调节器及固定螺丝组成。2006年6月至2009年10月共收治15例不稳定型骨盆骨折累及骶髂复合体,男6例,女9例;年龄19-60岁,平均45．6岁。不稳定型骨盆骨折经骶髂关节韧带3例,经骶骨Ⅰ区5例,累及骶骨Ⅱ区5例,累及骶骨Ⅲ区2例。15例患者均采用骶髂关节空心钉内固定导向器引导术中S1椎弓根空心钉的操作,共置入18枚S,椎弓根空心钉。结果术后CT及X线片示18枚S1椎弓根空心钉置入位置准确,与术前设计相比,具有相同或相近的TSA及SSA。结论骶骼关节空心钉内固定导向器设计合理,使用方便,能提高S1椎弓根空心钉置入的准确性,提高置入质量,且可显著减少X线机的透视次数。     

Pedicle axis view combined by sacral mapping can decrease fluoroscopic shot count in percutaneous iliosacral screw placement

BackgroundPercutaneous iliosacral screw fixation of the posterior pelvic ring is a demanding procedure with high exposure to radiation. The conventional technique includes the use of three classical projections with the C-arm: inlet, outlet, and true lateral views. A projection in the axis of the upper sacral alar pedicles with a 30° cephalad and 30° ventral oblique view would help in obtaining a more accurate visualization of the safe corridor. Two subcutaneously placed K-wires, one placed horizontally and one vertically, may facilitate the starting point and aim changes by offering the surgeon an option for exactly matching the position of the sacrum with the image. The purpose of this study was to detect if the radiation application could be decreased by our new methodology.MethodsSeventeen patients with pelvic posterior ring disruptions, in which percutaneous iliosacral screw placement was indicated, were included in the study. Group 1 comprised 7 patients in whom conventional projections and technique were used. Group 2 comprised 10 patients in whom 30°–30° projection and sacral mapping technique via two subcutaneous K-wires were applied. Radiation exposure time, total fluoroscopic shot count, fluoroscopic shot count needed for only guide wire and screw placement, radiation dose, and complications were compared between the two groups.ResultsThe median number of fluoroscopic images for guide and screw placement was 132 (56–220) and 29.5 (19–83) in Groups 1 and 2, respectively, and the difference was statistically significant (p < 0.001). The median total fluoroscopic radiation time was 138 (68–234) and 52 (28–77) s in Groups 1 and 2, respectively, and the difference was significant (p < 0.001). Group 1 had a significantly higher median radiation dose than Group 2 [3020 (1502–6032) vs. 1192 (426–2359); (p = 0.001)].ConclusionsIliosacral screw placement with the help of sacral mapping and a fourth view, “30°–30°”, helps the surgeon to markedly reduce the fluoroscopic shots, radiation time and dose during guide wire and screw placement.Level of evidenceTherapeutic, Level II.     

前环皮下内置外固定架联合后环骶髂螺钉治疗不稳定骨盆骨折

目的评估应用前环皮下内置外固定架(internal fixation,INFIX)联合后环骶髂螺钉治疗不稳定骨盆骨折的临床疗效。方法2016年8月-2017年9月,采用前环皮下INFIX联合后环骶髂螺钉治疗不稳定骨盆骨折19例。其中男14例,女5例;年龄17~69岁,平均40.6岁。致伤原因:交通事故伤11例,高处坠落伤5例,重物砸伤3例。骨折根据Tile分型,B1型2例,B2型6例,C型11例。前环损伤包括双侧耻骨坐骨支骨折12例,单侧耻骨坐骨支骨折5例,耻骨联合分离2例;后环损伤包括骶髂韧带损伤2例,单侧髂骨骨折3例,单侧骶骨骨折11例,单侧骶髂关节脱位2例,双侧骶骨骨折1例。受伤至手术时间2~11 d,平均6.1 d。记录术中出血量及手术时间,观察骨折愈合情况及术后并发症情况。采用Matta评分标准评价骨折复位情况,采用Majeed评分标准评估患者术后功能。结果患者手术时间为47~123 min,平均61.4 min;术中出血量为50~115 mL,平均61.1 mL。术后1例发生植钉处切口浅表感染,1例发生单侧股外侧皮神经激惹,经相应处理后治愈或症状消失。无泌尿系统、生殖系统及肠道等损伤。所有患者均获随访,随访时间12~25个月,平均18.1个月。术后骨折均愈合,愈合时间8~13周,平均9.5周;无骨折不愈合、延迟愈合,内固定物松动、断裂等情况发生。2例术前腰骶丛神经损伤患者中,1例功能完全恢复,1例残留轻度跛行症状。末次随访时采用Matta评分标准评价骨折复位情况,获优13例、良6例,优良率100%;采用Majeed评分标准评价功能,获优15例、良4例,优良率100%。结论应用前环皮下INFIX联合后环骶髂螺钉治疗不稳定骨盆骨折临床疗效满意,并发症较少,是一种微创治疗骨盆环损伤的有效方法。