Percutaneous screw placement in the lumbar spine with a modified guidance technique based on 3D CT navigation system

Abstract

Several guidance techniques have been employed to increase accuracy and reduce surgical time during percutaneous placement of pedicle screws (PS). The purpose of our study was to present a modified technique for percutaneous placement of lumbar PS that reduces surgical time. We reviewed 23 cases of percutaneous PS placement using our technique for minimally invasive lumbar surgeries and 24 control cases where lumbar PS placement was done via common technique using Jamshidi needles (Becton, Dickinson and Company, Franklin Lakes, NJ, USA). An integrated computer-guided navigation system was used in all cases. In the technique modification, a handheld drill with a navigated guide was used to create the path for inserting guidewires through the pedicles and into the vertebral bodies. After drill removal, placement of the guidewires through the pedicles took place. The PS were implanted over the guidewires, through the pedicles and into the vertebral bodies. Intraoperative computed tomography was performed after screw placement to ensure optimal positioning in all cases. There were no intraoperative complications with either technique. PS placement was correct in all cases. The average time for each PS placement was 6.9 minutes for the modified technique and 9.2 minutes for the common technique. There was no significant difference in blood loss. In conclusion, this modified technique is efficient and contributes to reduced operative time.

Keywords: Pedicle screws (PS); computed tomography (CT); navigation; percutaneous technique.

Figure 1

Percutaneous implantation of the navigational frame in the posterior superior iliac bone.

Figure 2

O-arm in the final position for intraoperative CT of the lumbar spine.

Figure 3

The navigation system used for guidance during the procedure (left screen). A camera is integrated into the system for the navigation of the instruments (placed above the two screens). The right screen is connected to the C-Arm.

Figure 4

Docking the navigated drill guide to the transverse process and facet junction (axial, sagittal, and coronal images of the lumbar spine based on the intraoperative CT scan). The schematic outside the vertebral body (left upper and lower images) shows the actual position of the drill guide at the entry point to the pedicle. The inner projection (middle upper and lower images) represents the path (trajectory) for screw placement that will be created after the cannulation. Images obtained by the navigational system.

Figure 5

Image of the drill that is used for pedicle and vertebral body cannulation through the navigated drill guide. The drill stop (arrow) is preset by the surgeon according to the length of the screw that is going to be used.

Figure 6

Cannulation of the pedicle is taking place through the navigated drill guide.

Figure 7

Fluoroscopic image showing the cannulation of the pedicle by the drill on the left side (upper arrow) and a pedicle screw is already placed (lower arrow). Note inserted guidewires on right side of image.

Figure 8

Images obtained from the navigational system (axial, coronal, and sagittal images of the lumbar spine) showing the screw trajectory during screw insertion to the lumbar spine above the guidewires.