Safety and efficacy of navigated trocarless pedicle screw placement: Technical note

Background: Standard open techniques for pedicle screws placement require extensive tissue dissection for optimal screw trajectory. Furthermore, they have been associated with extensive blood loss, long hospital stays and, consequently, significant costs. Objective: To describe a percutaneous pedicle screw fixation performed with a novel navigated "one-step" system, underlining the safety and effectiveness of such technique. Methods: During a 43-month period, 43 patients with 230 pedicle screws were evaluated. Percutaneous pedicle screw fixation was performed in the lumbosacral region in 5 patients (12%), lumbar region in 13 (30%), thoracolumbar region in 21 (49%) and thoracic region in 4 (9%). We have compared the accuracy rates of screw placement achieved with percutaneous pedicle screw fixation using fluoroscopy, and neuronavigated percutaneous pedicle screw fixation using an innovative "one-step" technique. Results: Statistical differences in screws placement accuracy between the group A and B were evaluated by Fisher exact test. The accuracy rate of pedicle screws placement in group with the intraoperative navigation system was higher than that of the group with fluoroscopy (P = 0.04). There was no hardware failure except 3 screws of Group A (1.3%) that pulled out few weeks after surgery, There were a total of 6 SAR (2.61%) and only 1 of them belonged to group B, without the need of revision surgery (0.61% out of the total neuronavigated stabilizations), while the other 5 represent 7.35% of the total screws placed with fluoroscopy. In our patient series the risk of mispositioning has been reduced by 14.95% with the use of the neuronavigation system, considering as malposition the set of IMP and SAR. Conclusions: Percutaneous pedicle screw fixation with neuronavigated "one-step" technique represents a safe and effective tool in minimally invasive spine surgery that deserves a further investigation and widespread diffusion.