# Clinical Accuracy and Length of Percutaneous Pedicle Screw (PPS) Insertion in the Thoracic and Lumbar Spine Under Two-Dimensional Fluoroscopy: A Comparative Study of PPS Placement With Guidewireless and Conventional Guidewire Systems

## TL;DR

A study compared two methods for inserting spine screws and found the newer system was just as accurate but used shorter screws.

## Contribution

The VIPER PRIME system's guidewireless design achieved comparable accuracy to conventional systems while using shorter screws.

## Key findings

- The VIPER PRIME system achieved 100% accuracy in screw placement compared to 98.5% for the conventional system.
- Only 22% of VIPER PRIME screws exceeded 85% of vertebral body length, versus 62% for conventional screws.
- No severe complications or revisions occurred in either group.

## Abstract

Introduction

Minimally invasive spine surgery, particularly percutaneous pedicle screw (PPS) placement, has gained popularity. The VIPER PRIME™ Spine System (DePuy Synthes, Raynham, Massachusetts, United States), introduced in 2018, was designed to eliminate guidewire complications. This study compared the accuracy and insertion length of PPS placement using the Viper Prime system and the conventional guidewire system under two-dimensional fluoroscopy.

Methods

A total of 46 patients (30 men, 16 women; mean age 72.9 years) who underwent PPS fixation between 2018 and 2022 were included. Patients were divided into two groups: the VIPER PRIME group (N-group) and the conventional group (C-group). A total of 263 screws were inserted in the N-group and 133 screws in the C-group. All procedures were performed using two-dimensional fluoroscopic guidance.

Results

The N-group demonstrated 263/263 (100%) screws placement accuracy, with all screws classified as Zdichavsky grade Ia or Ib (used with permission from Springer Nature). The C-group achieved 131/133 (98.5%) screws placement accuracy. No severe complications or screw revisions occurred in either group. Analysis of screw length showed that only 59/263 (22%) screws in the N-group exceeded 85% of the vertebral body length, compared to 82/133 (62%) screws in the C-group.

Conclusion

The VIPER PRIME system demonstrated accuracy comparable to the conventional system in PPS placement under two-dimensional fluoroscopy. Its high precision is likely attributable to the ease of positioning and the relatively thick stylet, which is designed to be firmly grasped at a short length, reducing deflection during insertion. However, the integrated screw design may lead to the use of shorter screws to avoid anterior cortical breach. In patients with osteoporosis or those requiring stronger fixation, careful preoperative planning using three-dimensional computed tomography is recommended to ensure optimal screw length and placement.