3D-imaging in percutaneous spine surgery using the Surgivisio system

Navigated pedicle screw insertion with the Surgivisio system: Malposition rate and risk factors - about 648 screws

PURPOSE

Pedicle screw malposition rates vary greatly in scientific literature depending on the chosen criteria. Different techniques have been developed to lower the risk of screw malposition. Our primary objective is to evaluate the malposition rate associated with the use of the Surgivisio navigation system and to identify risk factors for screw malposition. The secondary objectives are to assess operating time and radiation data.

MATERIALS AND METHODS

We performed a monocentric retrospective consecutive case series. All patients operated for pedicle screw implantation using the Surgivisio system between September 2017 and June 2020 were included. Screw positioning was evaluated on postoperative CT scans using Heary and Gertzbein classifications. Thirteen potential risk factors for screw malposition were hypothesized and tested with a univariate and multivariate analysis.

RESULTS

Six hundred and forty-eight screws could be evaluated in 97 patients. Our study reported a 92.4% satisfactory screw implantation rate with a mean operative time per screw of 14.5±6.7minutes and a patient effective dose of 0.47±0.31 mSv per screw. One screw was neurotoxic and required an early revision (0.15%). Three risk factors for screw malposition have been identified in a multivariate analysis: female gender (OR=2.13 [1.11; 4], p=0.0219), an implantation level above D10 (OR=2.17 [1.13; 4.16], p=0.0197), and an "open" surgery (as opposed to percutaneous) (OR=3.47 [1.83; 6.56], p=0.0002).

CONCLUSION

Pedicle screw malposition rate and operative time with the Surgivisio navigation system are comparable with those reported in scientific literature. We theorized that intraoperative patient reference displacement could be a major cause of navigation failure.

LEVEL OF EVIDENCE

IV.

Surgical tips for the implantation of BDYNTM dynamic stabilization system: combining spinal navigation with motion preservation for low-grade lumbar degenerative spondylolisthesis

BACKGROUND

As required in every dynamic stabilization system, the implantation of the BDYNTM device implies a perfect positioning of the screws and rods to benefit from its biomechanical properties. To achieve this goal, intra-operative imaging seems mandatory.

METHOD

Through a case report of a patient with symptomatic grade I lumbar degenerative spondylolisthesis, we present the surgical tips for the implantation of BDYNTM dynamic stabilization system under the assistance of spinal navigation Surgivisio® 2D/3D.

CONCLUSION

The pedicular screw convergence, their placement in the pedicles, and the proper alignment of the BDYNTM system placed in neutral position are important steps of the surgery. Intra-operative spinal navigation helps achieving precise and safe positioning of the dynamic stabilization BDYNTM device taking optimal advantages of its biomechanical characteristics.

Virtual Scoliosis Surgery Using a 3D-Printed Model Based on Biplanar Radiographs

The aim of this paper is to describe a protocol that simulates the spinal surgery undergone by adolescents with idiopathic scoliosis (AIS) by using a 3D-printed spine model. Patients with AIS underwent pre- and postoperative bi-planar low-dose X-rays from which a numerical 3D model of their spine was generated. The preoperative numerical spine model was subsequently 3D printed to virtually reproduce the spine surgery. Special consideration was given to the printing materials for the 3D-printed elements in order to reflect the radiopaque and mechanical properties of typical bones most accurately. Two patients with AIS were recruited and operated. During the virtual surgery, both pre- and postoperative images of the 3D-printed spine model were acquired. The proposed 3D-printing workflow used to create a realistic 3D-printed spine suitable for virtual surgery appears to be feasible and reliable. This method could be used for virtual-reality scoliosis surgery training incorporating 3D-printed models, and to test surgical instruments and implants.

Screw misplacement in percutaneous posterior pelvic iliosacral screwing with and without navigation: A prospective clinical study of 174 screws in 127 patients

BACKGROUND

Recent studies of iliosacral screw fixation performed using intraoperative navigation systems have shown promising results. The Surgivisio Platform is a new-generation three-dimensional intraoperative navigation tool that has been used at our institution for 2years. The aim of this prospective study was to assess the contribution of navigation in terms of iliosacral screw positioning accuracy and of radiation exposure, by comparing outcomes with vs. without navigation.

HYPOTHESIS

Navigation allows more accurate percutaneous iliosacral screw positioning regardless of the type of screw fixation (with sacral dysmorphism and/or cemented screw fixation and/or multiple screw fixation).

MATERIALS AND METHODS

Between January 2018 and December 2019, consecutive patients who underwent percutaneous iliosacral screw fixation of pelvic ring fractures without vertical instability were included in this single-centre prospective study. Screw position accuracy was evaluated by postoperative high-resolution computed tomography (HRCT). Operative time, radiation dose, and complications were recorded.

RESULTS

We included 127 patients with 174 iliosacral screws, of which 129 were positioned under fluoroscopic guidance and 45 using navigation. According to the modified Gras classification, 7% (12/174) of the screws were incorrectly positioned and 2% (4/174) required repositioning. The frequency of screw malposition was not significantly different between the fluoroscopy and navigation groups (8.5%, 11/129 vs. 2.2%, 1/45, respectively; p=0.19). However, screw position in dysmorphic sacra was significantly better with navigation (p=0.04), whereas no significant difference in final screw position was found for cemented or multiple screw implantations. In the navigation group, the operative time was significantly longer (28.2min vs. 21.6min, p=0.003), and the mean dose-area product significantly greater (6.6Gy·cm² vs. 4.9Gy·cm², p=0.02). The complication rates were not different between the two groups.

CONCLUSION

In patients who have pelvic ring fractures without vertical instability, navigation of percutaneous iliosacral screw placement using the Surgivisio Platform improves screw positioning in dysmorphic sacra, at the cost of a longer operative time and greater radiation exposure of the patient.

LEVEL OF EVIDENCE

II, prospective study.

Does intraoperative 3D navigation improve SpineJack vertebral augmentation in thoracic and lumbar compression fracture?

INTRODUCTION

The aim of this retrospective study was to evaluate the effect of navigation on the positioning of the SpineJack implant in the treatment of thoracic and lumbar compression fractures.

METHODS

Between January 2018 and December 2019, all patients operated on for thoracic or lumbar fracture using the SpineJack device in stand-alone were included in this single-center study. The positioning of the SpineJack implant was analyzed on axial CT views by measuring the angle between the axis of the pedicle and the axis of the final implant. The relationships between implant positioning and the use of navigation or fluoroscopy, pedicle dimensions and levels of injury were analyzed. Surgical time, radiation exposure, radiological findings and complications were assessed.

RESULTS

One hundred patients were included, for 103 fractured vertebrae and a total of 205 implants, 148 placed under standard fluoroscopy and 57 with the Surgivisio navigation system. For pedicle diameters≥5mm (165 implants), the positioning of the implant relative to the axis of the pedicle was significantly better in the navigation group: 2°±1.4° (range, 0-7°) in the fluoroscopy group versus 1.2°±1.1° (range, 0-5°) in the navigation group (p=0.04). There were no significant differences in reduction of vertebral kyphosis angle or mean operating time. Dose area product (DAP) was significantly higher with navigation: 4.43Gy.cm² versus 0.47Gy.cm² (p<0.001) and dose to the surgeon significantly lower: 0.5 versus 1.6μSv (p<0.001). No difference was found regarding complications. Subgroup analysis showed significantly greater operative time and patient irradiation in the fluoroscopy group when pedicle diameter was less than 5mm.

CONCLUSION

This study demonstrates the interest of navigation for positioning the SpineJack implant with respect to the pedicle axis in vertebrae with pedicle diameter≥5mm. This study also confirmed the reliability of navigation and lower radiation dose to the surgeon, regardless of the fracture level. Navigation reduced operating time and patient irradiation for vertebrae with pedicle diameter<5mm.

LEVEL OF EVIDENCE

IV; retrospective study.