[Integrated navigation. Preclinical evaluation and initial clinical experience]

3D-based navigation in posterior stabilisations of the cervical and thoracic spine: problems and benefits. Results of 451 screws

INTRODUCTION

Navigated procedures in spinal surgery have been established due to an increasing demand for precision. Especially, 3D C-arms connected to navigation systems are being used more often and can be utilised intraoperatively for the planning and controlling of screw positions. This prospective study analyses our experiences with 3D-based navigation in posterior stabilisations in the cervical and thoracic spine.

METHODS

A 3D C-Arm (Ziehm Vision Vario 3D(®)) was connected to a navigation system (VectorVision, Brainlab(®)) and used for the placement of, in total, 451 screws among 67 patients. Of those, 14 patients had to undergo operations in the cervical and 53 in the thoracic spine. Postoperatively, the positioning was observed with computed tomography (CT).

RESULTS

The application time is approximately 6 min. In total, 354/451 (78.5%) screws could be inserted assisted with navigation, and 272/451 (60.3%) were controlled intraoperatively. Regarding the cervical spine, in 87.1% (61/70) of the screws, the navigation procedure was uneventful. The positioning of 63.2% (43/68) of the screws was checked intraoperatively. In the upper thoracic spine, 77% (293/381) could be placed with navigation and 59.6% (227/381) were controlled intraoperatively. Occasionally, the scanning setup was problematic. Correct placement was seen in 92.7% of screws; for the remaining screws, no revision was needed.

CONCLUSIONS

Intraoperative 3D imaging navigation for posterior spinal stabilisations is technically feasible and reliable in clinical use. The image quality depends on the individual bone density. With undisturbed visibility of the vertebral body, the reliability of 3D-based navigation is comparable to that of CT-based procedures. Additionally, it has the advantage of skipping the preoperative acquisition of data as well as the matching process, with reduced radiation doses.

[3D navigated osteosynthesis of calcaneal fractures. Open and minimally invasive techniques]

BACKGROUND

It is hypothesized that misplacement of sustentacular screws during osteosynthesis of intraarticular calcaneal fractures can be reduced with the help of navigation. A method for three-dimensional (3D) navigated placement of sustentacular screws for treating intraarticular calcaneal fractures is presented and evaluated.

MATERIAL AND METHODS

11 consecutive patients with 15 intraarticular calcaneal fractures were treated using 3D navigation. In 12 cases osteosynthesis was done through an extended lateral approach; in three cases, it was achieved through a minimally invasive percutaneous approach. For verification and documentation of the placed screws, a second 3D scan was performed.

RESULTS

A total of 20 screws were placed using 3D navigation. None of the navigated screws was misplaced. Extra operating time due to navigation averaged 11.9 minutes (+/-2.2 min).

CONCLUSION

Through a combination of intraoperative 3D imaging and navigation, placement of sustentacular screws is possible and can yield precise and reliable results. Especially in minimally invasive treatment, a high quality of osteosynthesis can be achieved.