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Pedicle Screw Insertion Accuracy Using O-Arm, Robotic Guidance, or Freehand Technique

A Comparative Study

Laudato, Pietro Aniello, MD, PhD; Pierzchala, Katarzyna, PhD; Schizas, Constantin, MD, FRCS

doi: 10.1097/BRS.0000000000002449

Study Design. A retrospective radiological study.

Objective. The aim of this study was to evaluate the accuracy of pedicle screw insertion using O-Arm navigation, robotic assistance, or a freehand fluoroscopic technique.

Summary of Background Data. Pedicle screw insertion using either “O-Arm” navigation or robotic devices is gaining popularity. Although several studies are available evaluating each of those techniques separately, no direct comparison has been attempted.

Methods. Eighty-four patients undergoing implantation of 569 lumbar and thoracic screws were divided into three groups. Eleven patients (64 screws) had screws inserted using robotic assistance, 25 patients (191 screws) using the O-arm, while 48 patients (314 screws) had screws inserted using lateral fluoroscopy in a freehand technique. A single experienced spine surgeon assisted by a spinal fellow performed all procedures. Screw placement accuracy was assessed by two independent observers on postoperative computed tomography (CTs) according to the A to D Rampersaud criteria.

Results. No statistically significant difference was noted between the three groups. About 70.4% of screws in the freehand group, 69.6% in the O arm group, and 78.8% in the robotic group were placed completely within the pedicle margins (grade A) (P > 0.05). About 6.4% of screws were considered misplaced (grades C&D) in the freehand group, 4.2% in the O-arm group, and 4.7% in the robotic group (P > 0.05). The spinal fellow inserted screws with the same accuracy as the senior surgeon (P > 0.05).

Conclusion. The advent of new technologies does not appear to alter accuracy of screw placement in our setting. Under supervision, spinal fellows might perform equally well to experienced surgeons using new tools. The lack of difference in accuracy does not imply that the above-mentioned techniques have no added advantages. Other issues, such as surgeon/patient radiation, fiddle factor, teaching suitability, etc., outside the scope of our present study, need further assessment.

Level of Evidence: 3

Spine Unit, Département des Neurosciences Cliniques, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland

Centre d’Imagerie BioMédicale (CIBM), École polytechnique fédérale de Lausanne, Lausanne, Switzerland

Neuro-Orthopaedic Spine Unit, Hirslanden Group of Private Hospitals, Clinique Cecil, Lausanne, Switzerland.

Address correspondence and reprint requests to Constantin Schizas, MD, FRCS, Clinique Cecil, Lausanne 1003, Switzerland; E-mail:

Received 17 March, 2017

Revised 14 May, 2017

Accepted 26 June, 2017

The manuscript submitted does not contain information about medical device(s)/drug(s).

No funds were received in support of this work.

No relevant financial activities outside the submitted work.

Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.