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Comparison of the Percutaneous Screw Placement Precision of Isocentric C-arm 3-dimensional Fluoroscopy-navigated Pedicle Screw Implantation and Conventional Fluoroscopy Method With Minimally Invasive Surgery

Nakashima, Hiroaki MD*; Sato, Kouji MD; Ando, Toshihiro MD; Inoh, Hidefumi MD; Nakamura, Hiroshi MD

doi: 10.1097/BSD.0b013e31819877c8
Original Articles

Study Design Retrospective clinical study to compare the percutaneous screw placement precision of isocentric C-arm (Iso-C) 3-dimensional fluoroscopy-navigated pedicle screw implantation and conventional fluoroscopy.

Objective The purpose of this study was to evaluate the accuracy of clinical percutaneous pedicle screw placement (PPSP) using Iso-C 3-dimensional fluoroscopy navigation.

Summary of Background Data The technique of PPSP recently has been applied to internal fixation for segmental lumbar instability as a form of minimally invasive spine surgery. The percutaneous insertion technique requires surgical skill and experience. The 3-dimensional fluoroscopy-based image-guidance navigation system has been proven to be effective in guiding accurate PPSP in the lumbar area of cadavers. However, there have been few clinical reports comparing the accuracy of Iso-C 3-dimensional fluoroscopy-navigated pedicle screw implantation and the conventional fluoroscopy method.

Methods Here, 300 percutaneous pedicle screws were evaluated; half of them were inserted under Iso-C 3-dimensional navigation and the others under fluoroscopy. The accuracy of pedicle screw placement was examined postoperatively using an axial 2-mm slice computed tomography. Screw malpositioning was classified either as exposed screw (<50% of the screw outside the pedicle) or perforated pedicle (>50% of the screw outside the pedicle boundaries).

Results Of the 150 pedicle screws placed with Iso-C 3-dimensional fluoroscopy-based image-guide assistance, 11 (7.3%) were classified as exposed screws and 0 (0%) as perforated pedicle. Of the 150 pedicle screws inserted under fluoroscopy, 18 (12%) were classified as exposed screw and 5 (3.3%) as perforated pedicle. The difference in frequency of screw misplacement between the procedure using Iso-C 3-dimensional fluoroscopy-based image-guide assistance and that using fluoroscopy was statistically significant (P<0.05; χ2 test).

Conclusions This study demonstrates the feasibility of placing percutaneous posterior lumbar pedicle screws with the assistance of Iso-C 3-dimensional navigation.

*Department of Orthopedic Surgery, Chubu Rosai Hospital

Department of Orthopaedic Surgery, Nagoya Daini Red Cross Hospital, Nagoya

Department of Orthopaedic Surgery, Anjo Kosei Hospital, Anjo, Japan

Reprints: Hiroaki Nakashima, MD, Department of Orthopedic Surgery, Chubu Rosai Hospital, 1-10-6 Komei, Minato-ku, Nagoya, Aichi 455-0018, Japan (e-mail:

Received for publication July 6, 2008; accepted December 8, 2008

© 2009 Lippincott Williams & Wilkins, Inc.