Accuracy of Percutaneous Pedicle Screw Placement after Single-Position versus Dual-Position Insertion for Lateral Interbody Fusion and Pedicle Screw Fixation Using Fluoroscopy

Abstract

Study design: Retrospective study.

Purpose: The purpose of this study was to compare the accuracy of percutaneous pedicle screw (PPS) placement between prone and lateral decubitus positions during lateral lumbar interbody fusion (LLIF) and to evaluate the tendency of PPS positioning based on simple computed tomography measurements with patients in the lateral decubitus position.

Overview of literature: There is insufficient information in the literature regarding the accuracy of inserting a PPS using fluoroscopy in patients in the lateral decubitus position.

Methods: We included 62 patients who underwent combined LLIF surgery and PPS fixation for degenerative lumbar spondylolisthesis with spinal canal stenosis. We compared the patient demographics and the accuracy of fluoroscopy-guided PPS placement between two groups: patients who remained in the lateral decubitus position for the pedicle screw fixation (single-position surgery [SPS] group) and those who were turned to the prone position (dual-position surgery [DPS] group).

Results: There were 40 patients in the DPS group and 22 in the SPS group. Of the 292 PPSs, only 12 were misplaced. In other words, 280/292 screws (95.9%) were placed correctly in the pedicle's cortical shell (grade 0). PPS insertion did not cause neurological, vascular, or visceral injuries in either group. The breach rates for the DPS and SPS groups were 4.1% (grade 1, 5 screws; grade 2, 3 screws; grade 3, 0 screw) and 4.1% (grade 1, 2 screws; grade 2, 2 screws; grade 3, 0 screw), respectively. Although there were no statistically significant differences, the downside PPS had more screw malpositioning than the upside PPS.

Conclusions: We found that PPS insertion with the patient in the decubitus position under fluoroscopic guidance might be as safe and reliable a technique as PPS insertion in the prone position, with a misplacement rate similar to that previously published.

Keywords: Accuracy; Dual-position surgery; Lateral lumbar interbody fusion; Percutaneous pedicle screw; Single-position surgery.

Fig. 1

(A, B) Intraoperative photograph of percutaneous pedicle screw insertion in the lateral decubitus position.

Fig. 2

The insertion angle (⋆) was measured by subtracting the angle between the line passing through the center of the percutaneous pedicle screw after surgery and using axial computed tomography scans.

Fig. 3

(A) Comparison of the insertion angle of percutaneous pedicle screws in L4 and L5 (n=190) after surgery between the dual-position surgery (DPS) and single-position surgery (SPS) groups. (B) Comparison between the DPS and SPS groups in L4. (C) Comparison between the DPS and SPS groups in L5. DP-PPS, dual-position percutaneous pedicle screw; SP-PPS, single-position percutaneous pedicle screw. *p<0.05, **p<0.01, and ***p<0.001 between groups.

Fig. 4

A 73-year-old female patient with degenerative spondylolisthesis underwent L4–5 XLIF+SP-PPS. (A) Immediate postoperative computed tomography scans showed a lateral misplacement of the L4 PPS on the downside (grade 2). (B) PPS insertion at L5 posed no problem. PPS, percutaneous pedicle screw; XLIF, extreme lateral interbody fusion; SP-PPS, single-position percutaneous pedicle screw.

Fig. 5

This figure is the same case as in Fig. 4. (A) Intraoperative radiograph evaluation. (B) Postoperative radiograph evaluation. Immediately after surgery, the radiograph did not seem to cause any problems with percutaneous pedicle screw (PPS) insertion. However, because we put a pillow (arrow) under the patient’s body, the patient’s body was rotated slightly, so we made the wrong decision during surgery and did not notice the PPS’s lateral displacement.