Template For Pedicle Screw Placement Research Articles

Real-Time Navigation with Guide Template for Pedicle Screw Placement Using an Augmented Reality Head-Mounted Device: A Proof-of-Concept Study.

This study aims to explore the real-time navigation with guide template using an augmented reality head-mounted device (ARHMD) for pedicle screw placement. The spatial coordinate relationships between augmented reality images and real objects were established through the custom-made guide template, and the registration and tracking were completed using an ARHMD. The feasibility and accuracy of this method were verified by pedicle screw placement in 2 lumbar models. According to the Gertzbein-Robbins grading scale, the accuracy of pedicle screw placement was assessed. The navigation errors were estimated by measuring the deviation values of entry point and trajectory angle. A total of 20 pedicle K-wires were placed into L1-L5 in 2 lumbar models, which were successfully completed, with an average time of 11.5min per model and 69s per screw. The overall K-wires placement accuracy was 100% (20 screws). The navigation error was 2.77 ± 0.82mm for the deviation value of entry point, and 3.03° ± 0.94° for the deviation value of trajectory angle. The application of an ARHMD combined with guide template for pedicle screw placement is a promising navigation approach.

A multi-level drill guide template improves the accuracy of pedicle screw placement in lumbar spine.

Free-hand technique is widely used in pedicle screw placement for lumbar spine and generally safe; however, screw malposition still occurs. To develop a novel multi-level drill guide template for pedicle screw placement in lumbar spine and evaluate its accuracy. Twelve lumbar cadaveric specimens were randomly allocated into guide template group (n=6) and free-hand group (n=6). Computed tomography (CT) scans were obtained for reconstruction of three-dimensional (3D) model of each lumbar vertebra, and further an individual guide template was designed. Then the templates and their corresponding vertebra were developed by rapid prototyping (RP) technology. With the guide of the templates, screws were inserted via mini-open Wiltse approach. The positions of the screws were assessed based on postoperative CT images. In total, 120 pedicle screws inserted (guide template group: n=60 vs. free-hand group: n=60). For all 30 vertebras in the guide template group, all pre-designed personalized drill guide templates can be fitted into the facet joints of each vertebra well. Furthermore, our results revealed a significant improvement for the guide template group in the accuracy rate (p=0.026). Armed with advantages of minimal invasion, enhanced accuracy and safety, the novel technique of multi-level drill guide template can be properly applied in pedicle screw placement for lumbar spine and promises to be a potential option in clinical application.

A medium invasiveness multi-level patient\u2019s specific template for pedicle screw placement in the scoliosis surgery

BackgroundSeveral methods including free-hand technique, fluoroscopic guidance, image-guided navigation, computer-assisted surgery system, robotic platform and patient’s specific templates are being used for pedicle screw placement. These methods have screw misplacements and are not always easy to be applied. Furthermore, it is necessary to expose completely a large portions of the spine in order to access fit entirely around the vertebrae.MethodsIn this study, a multi-level patient’s specific template with medium invasiveness was proposed for pedicle screw placement in the scoliosis surgery. It helps to solve the problems related to the soft tissues removal. After a computer tomography (CT) scan of the spine, the templates were designed based on surgical considerations. Each template was manufactured using three-dimensional printing technology under a semi-flexible post processing. The templates were placed on vertebras at four points—at the base of the superior-inferior articular processes on both left–right sides. This helps to obtain less invasive and more accurate procedure as well as true-stable and easy placement in a unique position. The accuracy of screw positions was confirmed by CT scan after screw placement.ResultsThe result showed the correct alignment in pedicle screw placement. In addition, the template has been initially tested on a metal wire series Moulage (height 70 cm and material is PVC). The results demonstrated that it could be possible to implement it on a real patient.ConclusionsThe proposed template significantly reduced screw misplacements, increased stability, and decreased the sliding & the intervention invasiveness.

Accuracy of a patient-specific template for pedicle screw placement compared with a conventional method: a meta-analysis.

Accurate placement of pedicle screws in spine surgery is a challenge for surgeons. Patient-specific template techniques have the potential for improving the accuracy of screw placement. The target of this analysis was to investigate differences in terms of accuracy of pedicle screw insertion between patient-specific template assistance and the conventional free-hand method for reconstruction of spinal stability. The Cochrane Library, Ovid, Web of Science, PubMed, EMBASE and CNKI database were searched until February 2017 for a systematic review, and several comparative studies were screened for comparisons of accuracies of pedicle screw insertion with patient-specific assistance and conventional methods. Primary outcomes extracted from papers that met the selection criterion were expressed as odds ratios for dichotomous outcomes with a 95% confidence interval. A χ 2 test and I 2 statistics were used to evaluate heterogeneity. A total of ten RCTs and two prospective cohort studies were finally chosen for the analysis of accuracy rates. Study quality was assessed using the Cochrane Collaboration's Tool and Newcastle-Ottawa Quality Assessment Scale. There were obvious differences between them, and the accuracy rate of screw implantation among a patient-specific template assistance set was statistically significantly higher than the conventional free-hand set (OR 95% CI 3.78-6.41, P<0.01); in vitro: OR 95% CI 3.93-7.42, P<0.01; in vivo: OR 95% CI 2.49-6.44, P<0.01. The template-assisted technique is superior to the conventional method for the reduction of pedicle violation. The template-assisted technique is a promising technique that should be considered as another available navigation tool for surgeons to improve the accuracy of pedicle screw placement. As an available technique for emerging applications in spine surgeries, this technique will face challenges but ultimately prove successfully.

CLINICAL APPLICATION OF A DRILL GUIDE TEMPLATE FOR PEDICLE SCREW PLACEMENT IN SEVERE SCOLIOSIS.

ABSTRACTObjective: To evaluate the accuracy and the effect of drill guide template for pedicle screw placement in severe scoliosis.Method: Eight patients with rigid scoliosis were enrolled, five males and three females, ranging from nine to 23 years old. A three-dimensional CT scan of the spine was performed and saved as a DICOM file type. The multi-level template was designed by Mimics software and manufactured according to the part of the most severe deformity. The drill template was placed on the corresponding vertebral surface. Pedicle screws were carefully inserted across the trajectory of the template. Postoperatively, the positions of the pedicle screws were evaluated by CT scan and graded for validation.Results: No spinal cord injury or nerve damage occurred. All patients had satisfactory outcomes. The abnormalities and the measures observed during operation were the same as those found in the preoperative period. The position of the pedicle screws was accurate, according to the postoperative X-ray and CT scan. The rate of scoliosis correction was 60%. Compared with controls, surgery time, blood loss and radiation were significantly lower.Conclusion: With the application of multi-level template, the placement of pedicle screws shows high accuracy in scoliosis with shorter surgical time, less blood loss and less radiation exposure. Level of Evidence III, Retrospective Comparative Study.

Preliminary application of a multi-level 3D printing drill guide template for pedicle screw placement in severe and rigid scoliosis

Accurate implantation of pedicle screw in spinal deformity correction surgeries is always challenging. We have developed a method of pedicle screw placement in severe and rigid scoliosis with a multi-level 3D printing drill guide template. From November 2011 to March 2015, ten patients (4 males and 6 females) with severe and rigid scoliosis (Cobb angle >70° and flexibility <30%)were included. Multi-level template was designed and manufactured according to the part (two or three levels) of the most severe deformity. The drill template was then placed on the corresponding vertebral surface. Then, pedicle screws were carefully inserted along the trajectories. The other screws were placed in free hand. After surgery, the positions of the pedicle screws were evaluated by CT scan and graded for validation. 48 screws were implanted using templates, other 104 screws in free hand, and the accuracies were 93.8 and 78.8%, respectively, with significant difference. The deformity correction ratio was 67.1 and 41.2% in coronal and sagittal plane post-operatively, respectively. The average operation time was 234.0±34.1min, and average blood loss was 557±67.4ml. With the application of multi-level template, the incidence of cortex perforation in severe and rigid scoliosis decreased and this technology is, therefore, potentially applicable in clinical practice.