快速成形个体化导航模板辅助枢椎椎板螺钉的植入

目的 观察快速成形(rapid prototyping,RP)个体化导航模板在C2椎板螺钉植入中的初步临床应用.方法 对患者行上颈椎CT连续扫描,三维重建软件Amira 3.1建立C2三维模型,以STL格式导出模型.在UG Imageware 12.0平台打开三维重建模型.利用逆向工程(reverse engineering,RE)原理寻找C2椎板螺钉的最佳进钉钉道.提取椎板的表面解剖学形态,建立与椎体后部解剖学形态一致的模板.拟合模板和椎板孔道成定位模板,将椎体和定位模板通过激光RP技术生产出实物模板,手术时利用实物导航模板与椎体的后部结构相吻合,通过导航孔进行C2椎板螺钉的定位,植入椎板螺钉.术后根据X线片和CT扫描评价椎板螺钉的位置.结果 采用RP导航模板为5例患者植入C2椎板螺钉,术后CT扫描显示椎板螺钉的位置准确,未出现相关C2椎板螺钉植入的并发症.结论 利用RE原理和RP技术生产出的导航模板具有较好的准确性,为C:椎板螺钉的置钉提供了一种新的方法 ,具有较大的应用前景.     

快速成型导向模板技术在枢椎椎板交叉螺钉置钉中的应用

 目的 验证在快速成型导向模板辅助下枢椎椎板交叉螺钉置钉的安全性、准确性及偏差因素分析。方法 选取正常颈椎标本18具,行螺旋CT扫描。扫描数据经Mimics软件三维重建后行枢椎椎板交叉螺钉最佳钉道的计算机辅助设计,建立与枢椎椎板及棘突后表面解剖结构互补的基板,组合形成导向模板。在激光快速成型机上进行导向模板实体化,利用导向模板辅助置钉。扫描置钉后的标本,分割重建螺钉钉道路径。将置钉前后的标本配对拟合,测量理想钉道与实际螺钉的进钉点及进钉角度。结果 上、下位椎板螺钉理想钉道长度分别为(29.12±1.39)、(29.62±1.40) mm;内倾角分别为56.20°±2.07°、56.02°±1.72°。下位椎板螺钉实际钉道内倾角和尾倾角分别为56.28°±1.54°、0.13°±0.65°;上位椎板分别为55.48°±1.75°、-0.19°±1.54°。下位椎板螺钉进钉点在X、Y、Z轴上的偏移分别为(0.69±1.79)、(2.54±4.86)、(0.63±1.37) mm;上位椎板分别为(0.64±1.61)、(2.36±4.85)、(0.62±1.38) mm。理想钉道与实际螺钉进钉点、钉道方向的差异无统计学差异。结论 利用数字化快速成型导向模板技术辅助枢椎椎板交叉螺钉置钉提高了置钉的安全性和准确性,理论上可降低椎动脉和脊髓损伤的风险。     

数字化导航模板在上颈椎椎弓根定位中的初步临床应用

目的 观察数字化导航模板在上颈椎椎弓根定位中的初步临床应用.方法 对患者进行CT连续扫描,三维重建软件Amira 3.1建立上颈椎三维模型,以STL格式导出模型.在UG Imageware 12.0平台打开三维重建模型,定位三维参考平面.利用RE原理寻找椎弓根的最佳进钉钉道.提取椎板的表面解剖学形态,建立与椎体后部解剖学形态一致的模板.拟合模板和椎弓根孔道成定位模板,将椎体和定位模板通过激光RP技术生产出实物模板,手术时利用建立的定位模板与椎体的后部结构相吻合,通过导航孔进行上颈椎椎弓根的定位,置入椎弓根螺钉.术后根据X线片和CT扫描评价椎弓根螺钉的位置.结果 通过3例患者建立了制作个体化导航模板的方法,术后CT扫描显示椎弓根螺钉的位置准确,未出现相关椎弓根钉置入并发症.结论 利用RE原理和RP技术生产出的导航模板具有较好的准确性,为上颈椎椎弓根置钉提供了一种新的方法,具有较大的应用前景.     

Placement of C2 laminar screws using three-dimensional fluoroscopy-based image guidance

The use of C2 laminar screws in posterior cervical fusion is a relatively new technique that provides rigid fixation of the axis with minimal risk to the vertebral artery. The techniques of C2 laminar screw placement described in the literature rely solely on anatomical landmarks to guide screw insertion. The authors report on their experience with placement of C2 laminar screws using three-dimensional (3D) fluoroscopy-based image-guidance in eight patients undergoing posterior cervical fusion. Overall, fifteen C2 laminar screws were placed. There were no complications in any of the patients. Average follow-up was 10 months (range 3–14 months). Postoperative computed tomographic (CT) scanning was available for seven patients allowing evaluation of placement of thirteen C2 laminar screws, all of which were in good position with no spinal canal violation. The intraoperative planning function of the image-guided system allowed for 4-mm diameter screws to be placed in all cases. Using modified Odom’s criteria, excellent or good relief of preoperative symptoms was noted in all patients at final follow-up. Eric W. Nottmeier, MD is a paid consultant for BrainLAB.     

标杆型3D打印导板辅助寰枢椎椎弓根置钉准确度分析

目的探讨标杆型3D打印导板辅助寰枢椎椎弓根置钉的可行性,并进行置钉准确度分析。方法 2014年6月—2015年8月,本院收治寰枢椎脱位患者21例,男12例,女9例;年龄12~54岁,平均42.6岁。术前使用Mimics 17.0软件和3-matic 9.0软件为每例患者制作标杆型3D打印导板,术中使用标杆型3D打印导板辅助寰枢椎椎弓根置钉,术后患者行颈椎CT平扫。在Mimics 17.0软件中,将手术前后的寰枢椎模型及螺钉配对拟合,调整空间坐标轴,测量并比较术前预设钉道与术后实际钉道的内倾角、头倾角、进钉点坐标。结果 21例患者手术顺利,手术时间(193±51)min,术中出血量(384±127)m L。共置入寰椎椎弓根螺钉30枚,枢椎椎弓根螺钉42枚。除2枚寰椎椎弓根螺钉侵入椎管≤2 mm外,其他螺钉均位于椎弓根骨皮质内。寰椎左右侧预设最佳钉道内倾角度分别为9.4°±1.8°、9.8°±1.6°,实际钉道内倾角度分别为8.7°±1.6°、10.6°±2.2°;左右侧预设最佳钉道头倾角度分别为8.9°±2.5°、8.8°±2.3°,实际钉道头倾角度分别为9.3°±2.9°、9.4°±3.5°。枢椎左右侧预设最佳钉道内倾角度分别为21.9°±6.6°、22.4°±6.9°,左右侧实际钉道内倾角度分别为24.1°±6.3°、20.8°±6.4°;左右侧预设最佳钉道头倾角度分别为23.7°±7.3°、24.2°±7.2°,左右侧实际钉道头倾角度分别为22.1°±7.9°、22.3°±7.6°。寰枢椎术后实际钉道与术前预设最佳钉道的内倾角、头倾角、进钉点坐标差异均无统计学意义(P0.05)。结论标杆型3D打印导板辅助寰枢椎椎弓根置钉方向可调整性好,置钉准确度较高,为临床寰枢椎置钉提供了一种新的方法。     

计算机辅助导航模板在下颈椎椎弓根定位中的临床应用

目的 利用逆向工程(reverse engineering,RE)原理和快速成型(rapid prototyping,RP)技术设计一种新的下颈椎椎弓根定位的方法,并探讨其临床应用.方法 采用患者CT连续扫描数据集,三维重建软件Amira 3.1建立颈椎三维模型,以STL格式导出模型.在UG Imageware 12.0平台打开三维重建模型,定位三维参考平面.利用RE原理寻找椎弓根的最佳进钉钉道.提取椎板的表面解剖学形态,建立与椎体后部解削学形态一致的模板.拟合模板和椎弓根孔道成定位模板,将椎体和定位模板通过激光Rp技术生产出实物模板,手术时利用建立的定位模板与椎体的后部结构相吻合,通过导航孔进行下颈椎椎弓根的定位,植入椎弓根螺钉.术后根据X线片和CT扫描评价椎弓根螺钉的位置.结果 建立了制作个体化导航模板的方法,通过RP技术生产出的导航模板具有较好的准确性,适用于颈椎椎弓根螺钉的导航定位.结论 利用RE原理和RP技术为颈椎椎弓根的定位提供了一种新的方法,该方法为下颈椎椎弓根螺钉植入提供了一种新的方法,具有较大的应用前景.     

Rapid prototype patient-specific drill template for cervical pedicle screw placement.

OBJECTIVE: To assess the feasibility and accuracy of a drill template for the placement of a cervical pedicle screw in a single vertebral level. MATERIALS AND METHODS: A volumetric CT scan was performed on a cadaver cervical spine. Using computer software, a drill template with a predefined trajectory was constructed that was designed to match the posterior surface of the right side of the fifth cervical vertebra. A physical template was created from the computer model using a rapid prototyping machine. The drill template was used to guide drilling of a pilot hole, and a CT scan was performed to assess the accuracy of this hole. A 3.5-mm diameter pedicle screw was placed in the pilot hole. The spine was then dissected to separate the vertebrae and the trajectory of the screw was visually inspected. RESULTS: The feasibility of this patient-specific rapid prototyping technique was demonstrated. Imaging and visual inspection confirmed accurate placement of the pilot hole and cervical pedicle screw without cortical violation. CONCLUSIONS: The potential use of drill templates to place cervical pedicle screws is promising. Our initial methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the cervical spine.     

Application of navigation template to fixation of sacral fracture using three-dimensional reconstruction and re-verse engineering technique

Objective: To provide a new method in the fixation of sacral fracture by means of three-dimensional reconstruc-tion and reverse engineering technique.Methods: Pelvis image data were obtained from three-dimensional CT scan in patients with sacral fracture. The data were transferred into a computer workstation. The three-dimensional models of pelvis were reconstructed using Amira 3.1 software and saved in STL format. Then the three-dimensional fracture models were imported into Imageware 9.0 software. Different situations of reduction (total reduction, half reduction and non-reduction) were simulated using Imageware 9.0 software. The best direction and loca-tion of extract iliosacral lag screws were defined using re-verse engineering according to these three situations and navigation templates were designed according to the ana-tomic features of the postero-iliac part and the channel. The exact navigational template was made by rapid prototyping.Drill guides were sterilized and used intraoperatively to as-sist in surgical navigation and the placement of iliosacral lag screws.Results: Accurate screw placement was confirmed with postoperative X-ray and CT scanning. The navigation template was found to be highly accurate. Conclusion: The navigation template may be a useful method in minimal-invasive fixation of sacroiliac joint fracture.     

改良金属个性化导航模板辅助颈椎椎弓根置钉的准确性

目的探讨利用激光选区熔化成型技术制作金属材质手术导航模板的可行性及准确性。方法选取新鲜成人正常颈椎标本(C_(1～6))8具,随机分为金属导航模板组(金属组)和树脂导航模板组(树脂组),每组4具。所有标本均通过CT扫描获取dicom格式数据,将数据导入计算机后,根据分组设计并制作金属或树脂颈椎椎弓根螺钉导航模板。2组分别在相应导航模板辅助下置入椎弓根螺钉,行CT钉道扫描,对2种模板的准确性和安全性进行评价。结果8具标本分别于C1～6的每个节段置入2枚螺钉,每组48枚,共计96枚。金属组置钉准确率为87.5%(42/48),树脂组为70.8%(34/48),2组比较差异有统计学意义(P 0.05)。金属组置钉安全率为97.9%(47/48),树脂组为93.8%(45/48),2组比较差异无统计学意义(P 0.05)。结论利用激光选区熔化成型技术制作的改良金属个性化导航模板具有良好的置钉准确性和安全性,为颈椎椎弓根螺钉的精确置入提供了一种新的方法。     

Correlation between computed tomography measurements and direct anatomic measurements of the axis for consideration of C2 laminar screw placement

BackgroundC2 laminar screws are becoming an increasingly used method of fixation. They allow for avoidance of fixation through the C2 pedicle, eliminating the risk of vertebral artery injury. Recent studies have described the anatomic considerations of this technique in a large cadaveric population. In clinical practice, however, direct measurement is impractical and preoperative imaging must be relied upon to determine whether or not this technique can be safely used.PurposeTo evaluate the ability of computed tomography (CT) to accurately assess critical dimensions of the C2 vertebrae with regard to intralaminar screw placement.Study design/settingCadaveric analysis.MethodsThe C2 vertebrae of 84 adult spines were randomly selected from a large cadaveric collection. Direct measurements were performed to determine laminar thickness, estimated screw length, and spinolaminar angle. Fine cut axial CT scans were then performed on all specimens and all measurements were repeated from these images. Correlation coefficients were calculated to determine the ability of CT scan to accurately determine these measurements.ResultsCT scan measurements were found to be highly correlated with direct measurements for both left and right mean laminar thickness (0.975 and 0.947, respectively). Screw lengths using CT scan were found to be significantly longer than previously reported direct measurements (24.8 vs. 28.8 mm; p<.01). The mean CT spinolaminar angle was 42.45°, whereas it was 48.47° on direct measurement. Correlation coefficient for spinolaminar angle measurements was low (0.23); however, this is likely because of measurement variability.ConclusionsGiven the high degree of correlation between CT measurements and direct anatomic measurements, we conclude that CT scan can accurately determine laminar thickness, a measurement critical to safe placement of intralaminar screws. It appears that longer screw lengths that were previously reported may be safely used while remaining intra-osseous. We continue to advocate preoperative planning using CT to identify patients whose lamina may be unable to accommodate safe screw placement using this technique.     

Rapid prototyping drill guide template for lumbar pedicle screw placement

To develop a novel method of spinal pedical stereotaxy by reverse engineering and rapid prototyping techniques, and to validate its accuracy by experimental and clinical studies. Methods: A 3D reconstruction model for the desired lumbar vertebra was generated by using the Mimics 10.11 software, and the optimal screw size and orientation were determined using the reverse engineering software. Afterwards, a drill template was created by reverse engi-neering principle, whose surface was the antitemplate of the vertebral surface. The drill template and its correspond-ing vertebra were manufactured using the rapid prototyping technique. Results: The accuracy of the drill template was con-firmed by drilling screw trajectory into the vertebral biomodel preoperatively. This method also showed its ability to cus-tomize the placement and size of each screw based on the unique morphology of the lumbar vertebra.The drill tem-plate fits the postural surface of the vertebra very well in the cadaver experiment. Postoperative CT scans for controlling the pedicle bore showed that the personalized template had a high precision in cadaver experiment and clinical application. No misplacement occurred by using the per-sonalized template. During surgery, no additional computer assistance was needed.Conclusions: The authors have developed a novel drill template for lumbar pedicle screw placement with good applicability and high accuracy. The potential use of drill templates to place lumbar pedicle screws is promising. Our methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the lumbar spine.     

Rapid prototyping drill guide template for lumbar pedicle screw placement

To develop a novel method of spinal pedical stereotaxy by reverse engineering and rapid prototyping techniques, and to validate its accuracy by experimental and clinical studies. Methods: A 3D reconstruction model for the desired lumbar vertebra was generated by using the Mimics 10.11 software, and the optimal screw size and orientation were determined using the reverse engineering software. Afterwards, a drill template was created by reverse engi-neering principle, whose surface was the antitemplate of the vertebral surface. The drill template and its correspond-ing vertebra were manufactured using the rapid prototyping technique. Results: The accuracy of the drill template was con-firmed by drilling screw trajectory into the vertebral biomodel preoperatively. This method also showed its ability to cus-tomize the placement and size of each screw based on the unique morphology of the lumbar vertebra.The drill tem-plate fits the postural surface of the vertebra very well in the cadaver experiment. Postoperative CT scans for controlling the pedicle bore showed that the personalized template had a high precision in cadaver experiment and clinical application. No misplacement occurred by using the per-sonalized template. During surgery, no additional computer assistance was needed.Conclusions: The authors have developed a novel drill template for lumbar pedicle screw placement with good applicability and high accuracy. The potential use of drill templates to place lumbar pedicle screws is promising. Our methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the lumbar spine.     

Rapid prototyping drill guide template for lumbar pedicle screw placement

To develop a novel method of spinal pedical stereotaxy by reverse engineering and rapid prototyping techniques, and to validate its accuracy by experimental and clinical studies. Methods: A 3D reconstruction model for the desired lumbar vertebra was generated by using the Mimics 10.11 software, and the optimal screw size and orientation were determined using the reverse engineering software. Afterwards, a drill template was created by reverse engi-neering principle, whose surface was the antitemplate of the vertebral surface. The drill template and its correspond-ing vertebra were manufactured using the rapid prototyping technique. Results: The accuracy of the drill template was con-firmed by drilling screw trajectory into the vertebral biomodel preoperatively. This method also showed its ability to cus-tomize the placement and size of each screw based on the unique morphology of the lumbar vertebra.The drill tem-plate fits the postural surface of the vertebra very well in the cadaver experiment. Postoperative CT scans for controlling the pedicle bore showed that the personalized template had a high precision in cadaver experiment and clinical application. No misplacement occurred by using the per-sonalized template. During surgery, no additional computer assistance was needed.Conclusions: The authors have developed a novel drill template for lumbar pedicle screw placement with good applicability and high accuracy. The potential use of drill templates to place lumbar pedicle screws is promising. Our methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the lumbar spine.     

Rapid prototyping drill guide template for lumbar pedicle screw placement

To develop a novel method of spinal pedical stereotaxy by reverse engineering and rapid prototyping techniques, and to validate its accuracy by experimental and clinical studies. Methods: A 3D reconstruction model for the desired lumbar vertebra was generated by using the Mimics 10.11 software, and the optimal screw size and orientation were determined using the reverse engineering software. Afterwards, a drill template was created by reverse engi-neering principle, whose surface was the antitemplate of the vertebral surface. The drill template and its correspond-ing vertebra were manufactured using the rapid prototyping technique. Results: The accuracy of the drill template was con-firmed by drilling screw trajectory into the vertebral biomodel preoperatively. This method also showed its ability to cus-tomize the placement and size of each screw based on the unique morphology of the lumbar vertebra.The drill tem-plate fits the postural surface of the vertebra very well in the cadaver experiment. Postoperative CT scans for controlling the pedicle bore showed that the personalized template had a high precision in cadaver experiment and clinical application. No misplacement occurred by using the per-sonalized template. During surgery, no additional computer assistance was needed.Conclusions: The authors have developed a novel drill template for lumbar pedicle screw placement with good applicability and high accuracy. The potential use of drill templates to place lumbar pedicle screws is promising. Our methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the lumbar spine.     

Rapid prototyping drill guide template for lumbar pedicle screw placement

To develop a novel method of spinal pedical stereotaxy by reverse engineering and rapid prototyping techniques, and to validate its accuracy by experimental and clinical studies. Methods: A 3D reconstruction model for the desired lumbar vertebra was generated by using the Mimics 10.11 software, and the optimal screw size and orientation were determined using the reverse engineering software. Afterwards, a drill template was created by reverse engi-neering principle, whose surface was the antitemplate of the vertebral surface. The drill template and its correspond-ing vertebra were manufactured using the rapid prototyping technique. Results: The accuracy of the drill template was con-firmed by drilling screw trajectory into the vertebral biomodel preoperatively. This method also showed its ability to cus-tomize the placement and size of each screw based on the unique morphology of the lumbar vertebra.The drill tem-plate fits the postural surface of the vertebra very well in the cadaver experiment. Postoperative CT scans for controlling the pedicle bore showed that the personalized template had a high precision in cadaver experiment and clinical application. No misplacement occurred by using the per-sonalized template. During surgery, no additional computer assistance was needed.Conclusions: The authors have developed a novel drill template for lumbar pedicle screw placement with good applicability and high accuracy. The potential use of drill templates to place lumbar pedicle screws is promising. Our methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the lumbar spine.     

Rapid prototyping drill guide template for lumbar pedicle screw placement

To develop a novel method of spinal pedical stereotaxy by reverse engineering and rapid prototyping techniques, and to validate its accuracy by experimental and clinical studies. Methods: A 3D reconstruction model for the desired lumbar vertebra was generated by using the Mimics 10.11 software, and the optimal screw size and orientation were determined using the reverse engineering software. Afterwards, a drill template was created by reverse engi-neering principle, whose surface was the antitemplate of the vertebral surface. The drill template and its correspond-ing vertebra were manufactured using the rapid prototyping technique. Results: The accuracy of the drill template was con-firmed by drilling screw trajectory into the vertebral biomodel preoperatively. This method also showed its ability to cus-tomize the placement and size of each screw based on the unique morphology of the lumbar vertebra.The drill tem-plate fits the postural surface of the vertebra very well in the cadaver experiment. Postoperative CT scans for controlling the pedicle bore showed that the personalized template had a high precision in cadaver experiment and clinical application. No misplacement occurred by using the per-sonalized template. During surgery, no additional computer assistance was needed.Conclusions: The authors have developed a novel drill template for lumbar pedicle screw placement with good applicability and high accuracy. The potential use of drill templates to place lumbar pedicle screws is promising. Our methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the lumbar spine.     

Rapid prototyping drill guide template for lumbar pedicle screw placement

To develop a novel method of spinal pedical stereotaxy by reverse engineering and rapid prototyping techniques, and to validate its accuracy by experimental and clinical studies. Methods: A 3D reconstruction model for the desired lumbar vertebra was generated by using the Mimics 10.11 software, and the optimal screw size and orientation were determined using the reverse engineering software. Afterwards, a drill template was created by reverse engi-neering principle, whose surface was the antitemplate of the vertebral surface. The drill template and its correspond-ing vertebra were manufactured using the rapid prototyping technique. Results: The accuracy of the drill template was con-firmed by drilling screw trajectory into the vertebral biomodel preoperatively. This method also showed its ability to cus-tomize the placement and size of each screw based on the unique morphology of the lumbar vertebra.The drill tem-plate fits the postural surface of the vertebra very well in the cadaver experiment. Postoperative CT scans for controlling the pedicle bore showed that the personalized template had a high precision in cadaver experiment and clinical application. No misplacement occurred by using the per-sonalized template. During surgery, no additional computer assistance was needed.Conclusions: The authors have developed a novel drill template for lumbar pedicle screw placement with good applicability and high accuracy. The potential use of drill templates to place lumbar pedicle screws is promising. Our methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the lumbar spine.     

Rapid prototyping drill guide template for lumbar pedicle screw placement

To develop a novel method of spinal pedical stereotaxy by reverse engineering and rapid prototyping techniques, and to validate its accuracy by experimental and clinical studies. Methods: A 3D reconstruction model for the desired lumbar vertebra was generated by using the Mimics 10.11 software, and the optimal screw size and orientation were determined using the reverse engineering software. Afterwards, a drill template was created by reverse engi-neering principle, whose surface was the antitemplate of the vertebral surface. The drill template and its correspond-ing vertebra were manufactured using the rapid prototyping technique. Results: The accuracy of the drill template was con-firmed by drilling screw trajectory into the vertebral biomodel preoperatively. This method also showed its ability to cus-tomize the placement and size of each screw based on the unique morphology of the lumbar vertebra.The drill tem-plate fits the postural surface of the vertebra very well in the cadaver experiment. Postoperative CT scans for controlling the pedicle bore showed that the personalized template had a high precision in cadaver experiment and clinical application. No misplacement occurred by using the per-sonalized template. During surgery, no additional computer assistance was needed.Conclusions: The authors have developed a novel drill template for lumbar pedicle screw placement with good applicability and high accuracy. The potential use of drill templates to place lumbar pedicle screws is promising. Our methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the lumbar spine.     

Rapid prototyping drill guide template for lumbar pedicle screw placement

To develop a novel method of spinal pedical stereotaxy by reverse engineering and rapid prototyping techniques, and to validate its accuracy by experimental and clinical studies. Methods: A 3D reconstruction model for the desired lumbar vertebra was generated by using the Mimics 10.11 software, and the optimal screw size and orientation were determined using the reverse engineering software. Afterwards, a drill template was created by reverse engi-neering principle, whose surface was the antitemplate of the vertebral surface. The drill template and its correspond-ing vertebra were manufactured using the rapid prototyping technique. Results: The accuracy of the drill template was con-firmed by drilling screw trajectory into the vertebral biomodel preoperatively. This method also showed its ability to cus-tomize the placement and size of each screw based on the unique morphology of the lumbar vertebra.The drill tem-plate fits the postural surface of the vertebra very well in the cadaver experiment. Postoperative CT scans for controlling the pedicle bore showed that the personalized template had a high precision in cadaver experiment and clinical application. No misplacement occurred by using the per-sonalized template. During surgery, no additional computer assistance was needed.Conclusions: The authors have developed a novel drill template for lumbar pedicle screw placement with good applicability and high accuracy. The potential use of drill templates to place lumbar pedicle screws is promising. Our methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the lumbar spine.     

Rapid prototyping drill guide template for lumbar pedicle screw placement

To develop a novel method of spinal pedical stereotaxy by reverse engineering and rapid prototyping techniques, and to validate its accuracy by experimental and clinical studies. Methods: A 3D reconstruction model for the desired lumbar vertebra was generated by using the Mimics 10.11 software, and the optimal screw size and orientation were determined using the reverse engineering software. Afterwards, a drill template was created by reverse engi-neering principle, whose surface was the antitemplate of the vertebral surface. The drill template and its correspond-ing vertebra were manufactured using the rapid prototyping technique. Results: The accuracy of the drill template was con-firmed by drilling screw trajectory into the vertebral biomodel preoperatively. This method also showed its ability to cus-tomize the placement and size of each screw based on the unique morphology of the lumbar vertebra.The drill tem-plate fits the postural surface of the vertebra very well in the cadaver experiment. Postoperative CT scans for controlling the pedicle bore showed that the personalized template had a high precision in cadaver experiment and clinical application. No misplacement occurred by using the per-sonalized template. During surgery, no additional computer assistance was needed.Conclusions: The authors have developed a novel drill template for lumbar pedicle screw placement with good applicability and high accuracy. The potential use of drill templates to place lumbar pedicle screws is promising. Our methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the lumbar spine.