1. Intraoperative Iso-C C-arm navigation surgery for spinal and pelvic trauma Kobe Red Cross Hospital Yasuo Ito K. Koshimune, T. Takigawa, S. Nakahara, T. Morita Dept. of Orthopaedic Surgery, Kobe Red Cross Hospital JAPAN

2. Conflict of Interest I (or a member of my immediate family) have not received anything of value from or stock in a commercial company or institution related directly or indirectly to the subject of this presentation. Kobe Red Cross Hospital Disclosure information We (or a member of our immediate family) have not received anything of value from or stock in a commercial company or institution related directly or indirectly to the subject of this presentation.

3. Background Cervical pedicle screw has been shown to provide excellent mechanical strength. Abumi et al Screw misplacement leads to injury of the spinal cord, root, and vertebral artery. Kobe Red Cross Hospital Studies recommend navigation-assisted surgery for cervical pedicle screw fixation in order to prevent complications and increase accuracy.

4. Limitations of conventional CT-based navigation system Kobe Red Cross Hospital Special markers or anatomic landmarks are needed. Manual matching (registration) is subject to potential errors and time-consuming. Repeated and segmented registration must be needed for each vertebra. Changes in the anatomy cannot be detected intra- operatively.

5. Kobe Red Cross Hospital 2D projections in DR mode (50 in 1 minute / 100 in 1-2 minutes) 3D reconstruction 3D volume data 256 slices/scan approx. (12 cm) 3 Iso-C 3D with navigation system No manual registration ! Entire spine is matched to navi. images ! 3D images of intraoperative anatomy can be detected ! Real Time Navigation !!

6. Objectives Kobe Red Cross Hospital To evaluate prospectively the accuracy, feasibility, advantages and applications of intra-operative Iso-C 3D in cervical spinal surgery

7. Kobe Red Cross Hospital Patients and Methods 290 cases 131:cervical, 126:thoracolumbar, 33:pelvic trauma Pedicle Screws 1435 screws cervical : 553 screws, thoracolumbar: 882 screws Lateral mass screws 86 screws Odontoid screws 6 screws Iliac screws 112 screws Iliosacral screws 10 screws

8. Kobe Red Cross Hospital Grade 1: screw threads cut into the cortex Grade 2: screw perforation of the cortex by up to 2 mm Grade 3: screw perforation of the cortex by more than 2 mm Grade 1 Grade ３ Post-operative evaluation of pedicle screws (Thin-cut CT, 1.25mm) Grade 2 and Grade 3 regarded as misplacements

9. Kobe Red Cross Hospital Grade 2 ( < 2 mm): 10 screws 22 screws Grade 3 ( > 2 mm): 4 screws 7 screws Cortical perforation up to 2 mm cervical 43 / 1435 screws ( 3.0 %) thoracolumbar No deterioration in the initial neurological status No injured or irritated nerve root No vascular injury Results – pedicle screw

10. Kobe Red Cross Hospital The patient is positioned on a non-metallic carbon table to maximize image quality and to minimize artifacts. Clinical workflow in registration-free 3D navigation surgery A reference arc is placed on a spinous process Carbon table and Mayfield cramp

11. Kobe Red Cross Hospital It takes 120 seconds to obtain and reconstruct the 3D data.

12. Kobe Red Cross Hospital The image data is transferred directly to the navigation system. The screw trajectory is prepared using a cervical awl by Kotani et al

13. Intraoperative images of Iso-CImages of the navigated awl Case Presentation Case 1 55 y.o. Male Odontoid fracture

14. Kobe Red Cross Hospital Intraoperative images of Iso-C Postoperative sagittal image Case Presentation Case 1 55 y.o. Male Odontoid fracture

15. Case Presentation Case 2 76 y.o. Female Hangman fracture Percutaneous awling Percutaneous insertion of the osteosythesis screw

16. Case Presentation Case 2 76 y.o. Female Hangman fracture Intraoperative images of Iso-C Postoperative images

17. Advantages of Iso-C 3D C-arm Kobe Red Cross Hospital １． Accurate correlation between 3D images and current patient anatomy ２． Navigational support based on updated image data Educational tool for mastering surgical technique Applicable to minimally invasive surgery

18. Review of cervical or thoracic pedicle screw literature Kobe Red Cross Hospital Thoracic Weinstein et al (1988) 32 screws 21% Vaccaro et al (1995) 90 41% Abitol et al (1996) 48 50% Liljenqvist et al (1997) 120 25% Xu et al (1998) 95 54.7% Cinotti et al (1999) 126 24% Cervical Abumi et al (2000) 669 6.7% With Navi. ( Thoracic ) Youkilis et al (2001) 224 8.5% With Navi. and Iso-C (trauma) Our cases 1435 3.0 % “Miss” Percentage

19. Kobe Red Cross Hospital Disadvantages and Pitfalls (Iso-C3D, navigation surgery) Image quality Cost Navigation system, Iso-C3D, Carbon bed, Mayfield headholder Operating staff for navigation surgery Mechanical or Human error Interference between reference arc and probe Blurring of navigation images Eye movement between the operative field and monitor

20. Kobe Red Cross Hospital Conclusions Registration-free navigation surgery with the Iso-C was successfully used in 100 consecutive initial patients with cervical lesions Intraoperative 3D navigation showed significant advance in the safety and accuracy of operative procedures. This system will assist in performing truly minimally invasive surgeries.