CT-to-fluoroscopy registration versus scan-and-plan registration for robot-assisted insertion of lumbar pedicle screws

OBJECTIVE Pedicle screw insertion for stabilization after lumbar fusion surgery is commonly performed by spine surgeons. With the advent of navigation technology, the accuracy of pedicle screw insertion has increased. Robotic guidance has revolutionized the placement of pedicle screws with 2 distinct radiographic registration methods, the scan-and-plan method and CT-to-fluoroscopy method. In this study, the authors aimed to compare the accuracy and safety of these methods. METHODS A retrospective chart review was conducted at 2 centers to obtain operative data for consecutive patients who underwent robot-assisted lumbar pedicle screw placement. The newest robotic platform (Mazor X Robotic System) was used in all cases. One center used the scan-and-plan registration method, and the other used CT-to-fluoroscopy for registration. Screw accuracy was determined by applying the Gertzbein-Robbins scale. Fluoroscopic exposure times were collected from radiology reports. RESULTS Overall, 268 patients underwent pedicle screw insertion, 126 patients with scan-and-plan registration and 142 with CT-to-fluoroscopy registration. In the scan-and-plan cohort, 450 screws were inserted across 266 spinal levels (mean 1.7 ± 1.1 screws/level), with 446 (99.1%) screws classified as Gertzbein-Robbins grade A (within the pedicle) and 4 (0.9%) as grade B (< 2-mm deviation). In the CT-to-fluoroscopy cohort, 574 screws were inserted across 280 lumbar spinal levels (mean 2.05 ± 1.7 screws/ level), with 563 (98.1%) grade A screws and 11 (1.9%) grade B (p = 0.17). The scan-and-plan cohort had nonsignificantly less fluoroscopic exposure per screw than the CT-to-fluoroscopy cohort (12 ± 13 seconds vs 11.1 ± 7 seconds, p = 0.3). CONCLUSIONS Both scan-and-plan registration and CT-to-fluoroscopy registration methods were safe, accurate, and had similar fluoroscopy time exposure overall.

Does the application of Robotics improve outcomes of pedicle screw insertion in spine surgery compared to conventional fluoroscopy guidance? A protocol for Systematic Review and Meta-Analysis

BackgroundPedicle screw insertion is routinely carried out in spine surgery that has traditionally been performed under fluoroscopy guidance. Robotic guidance has recently gained popularity in order to improve the accuracy of screw placement. However, it is unclear whether the use of robotics alters the accuracy of screw placement or clinical outcomes.ObjectivesThis systematic review aims to compare the results of pedicle screws inserted under fluoroscopy guidance, with those inserted under robotic guidance, in terms of both short-term radiographic outcomes, as well as long-term clinical outcomes.MethodsThis systematic review will be conducted according to the PRISMA guidelines. A literature search will be conducted on the electronic databases of PubMed, Embase, Scopus, and Ovid with a pre-determined search strategy. A manual bibliography search of included studies will also be done. Original articles in English that directly compare pedicle screw insertion under robotic guidance to those inserted under fluoroscopy guidance will be included. Data on outcomes will be extracted from included studies and analysis carried out with the help of appropriate software.

Patient-Matched 3-D-Printed Guides for the Insertion of Cervical Pedicle Screws in Tumor Surgery

Background. Pedicle screw fixation in the cervical spine provides biomechanical advantages compared to other stabilization techniques. However, pedicle screw insertion in this area is challenging due to the anatomical conditions with a high risk of breaching the small pedicles and violating the vertebral artery or neural structures. Today, several techniques to facilitate screw insertion and to make the procedure safer are used. 3-D-printed patient-matched guides based on a CT reconstruction are a helpful technique which allows to reduce operation time and to improve the safety of pedicle screw insertion at the cervical spine. Cases. 3-D-printed patient-matched drill guides based on a CT scan with a 3-D reconstruction of the spine were used in two challenging cervical spine surgical tumor cases to facilitate the implantation of the pedicle screws. The screw position was controlled postoperatively by means of the routinely performed CT scan. Results. Postoperative imaging (conventional radiographs and CT scan) revealed the correct position of the pedicle screws. The time needed for screw insertion was short, and the need for intraoperative fluoroscopy could be reduced. There was no intra- or postoperative complication related to the pedicle screw implantation. Both tumors could be removed completely. Conclusion. These preliminary results show that 3-D-printed patient-specific guides are a promising tool to support and facilitate the implantation of cervical pedicle screws. The time needed for insertion is short, and intraoperative fluoroscopy time can be reduced. This technique allows for both a meticulous preoperative planning and a correct and therefore safe intraoperative positioning of cervical spine pedicle screws.

727 Robotic Assisted Versus Fluoroscopic Guided Approach in Pedicle Screw Insertion: A Systematic Review and Meta-Analysis

Aim The robotic assisted surgery has become prevalent in most of the surgical subspecialty. The adaption of such technique in spine surgery has resulted in minimising several issues encountered with fluoroscopic guided approach. The aim of this study is to compare the outcomes of robotic assisted approach and fluoroscopic guided approach in pedicle screw insertion. Method PUBMED, EMBASE, MEDLINE and CENTRAL database were systematically searched from its inception until November 2020. All the studies comparing robotic assisted surgery and fluoroscopic guided approach in pedicle screw insertion were included for quantitative and qualitative analysis. Results Twenty-eight studies enrolling 2105 patients (robotic group: 1027, fluoroscopic: 1078) and total screws of 8668 screws (robotic group: 4217, fluoroscopic group: 4451) were eligible for inclusion, these studies consisted of 19 observational studies, 7 randomised controlled trials (RCTs) and 2 cadaveric study. Robotic assisted approach was associated with significantly higher accuracy (Grade A+B) (OR = 2.34; P &lt; 0.0001) and distance between pedicle and screw (MD: 1.69; P = 0.001), lower incident of facet joint violation (OR = 0.22; P &lt; 0.00001), screw revision (OR = 0.38; P = 0.009), intraoperative blood loss (MD: -116.95; P = 0.0006), shorter pedicle screw placement time (MD: -4.66; P &lt; 0.00001), radiation exposure time (MD:-5.27; P = 0.0001), radiation dose (MD:-22.30; P = 0.0002) and postoperative hospital stay (MD: -0.79; P = 0.02) compared to fluoroscopic guided approach. There was no significant difference in operative time and wound infection. Conclusions In this meta-analysis, robotic assisted approach is more effective in achieving better clinical outcomes compared to fluoroscopic guided technique in pedicle screw insertion. However, future adequately powered RCTs are warranted to generate standardised outcomes.

Accuracy assessment of pedicle screw insertion with patient specific 3D‑printed guides through superimpose CT-analysis in thoracolumbar spinal deformity surgery

Purpose In order to avoid pedicle screw misplacement in posterior spinal deformity surgery, patient specific 3D‑printed guides can be used. An accuracy assessment of pedicle screw insertion can be obtained by superimposing CT-scan images from a preoperative plan over those of the postoperative result. The aim of this study is to report on the accuracy of drill guide assisted pedicle screw placement in thoracolumbar spinal deformity surgery by means of a superimpose CT-analysis. Methods Concomitant with the clinical introduction of a new technique for drill guide assisted pedicle screw placement, the accuracy of pedicle screw insertion was analyzed in the first patients treated with this technique by using superimpose CT-analysis. Deviation from the planned ideal intrapedicular screw trajectory was classified according to the Gertzbein scale. Results Superimpose CT-analysis of 99 pedicle screws in 5 patients was performed. The mean linear deviation was 0.92 mm, the mean angular deviation was 2.92° with respect to the preoperatively planned pedicle screw trajectories. According to the Gertzbein scale, 100% of screws were found to be positioned within the “safe zone”. Conclusion The evaluated patient specific 3D-printed guide technology was demonstrated to constitute a safe and accurate tool for precise pedicle screw insertion in spinal deformity surgeries. Superimpose CT-analysis showed a 100% accuracy of pedicle screw placement without any violation of the pedicle wall or other relevant structures. We recommend a superimpose CT-analysis for the first consecutive patients when introducing new technologies into daily clinical practice, such as intraoperative imaging, navigation or robotics.

Stress distribution of different lumbar posterior pedicle screw insertion techniques: a combination study of finite element analysis and biomechanical test

At present, the pedicle screw is the most commonly used internal fixation device. However, there are many kinds of common posterior pedicle screw insertion techniques performed to reconstruct the lumbar stability. Therefore, spinal surgeons often face a difficult choice. The stress distribution of internal fixation system is an important index for evaluating safety. Unfortunately, little had been known about the difference of stress distribution of screw-rod systems that established by Roy-Camille, Magerl and Krag insertion techniques. Here, combination of finite element analysis and model measurement research was adopted to evaluate the difference of stress. Following different pedicle screw insertion techniques, three lumbar posterior surgery models were established after modeling and validation of the L1–S1 vertebrae finite element model. By analyzing the data, we found that stress concentration phenomenon was in all the postoperative models. Roy-Camille and Magerl insertion techniques led to the great stress on screw-rod systems. Then, fresh frozen calf spines were selected as a model for subsequent measurements. Fitted with a specially designed test pedicle screw, L5–L6 vertebrae were selected to repeat and verify the results of the finite element analysis. With the aid of universal testing machine and digital torque wrench, models simulated flexion, extension, lateral bending and rotation. Finally, the strain value was captured by the strain gauge and was then calculated as the stress value. Krag and Magerl were found to be the safer choice for pedicle screw insertion. Overall, our combination method obtained the reliable result that Krag insertion technique was the safer approach for pedicle screw implantation due to its relatively dispersive stress. Therefore, without the consideration of screw size, pedicle fill, bone density, and bone structures, we recommend the Krag insertion technique as the first choice to reconstruction of lumbar stability. Additionally, the combination method of finite element analysis and strain gauge measurement can provide a feasible way to study the stress distribution of spinal internal fixation.