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Increased Accuracy in Lumbar Pedicle Screw Placement using Three Dimensional Image Guidance 2013

Category Interventional Austin C. Bourgeois, MD, BS
Judson Gash, MD
Rupert Stanborough
John Prenshaw
Rashad Daker, MD
Patrick Barlow
Geoffrey Laing, MD
William S. Reid, MD
Purpose Over the past 10 years, advanced imaging and minimally invasive techniques have achieved increased utilization in transforamainal lumbar interbody fusion (TLIF).  Three-dimensional stereotactic navigation utilizing intraoperative computed tomography (CT) is a technique that aims to reduce operative morbidity via increasing the accuracy of pedicle screw placement.  While preliminary data support this technique, it remains incompletely explored over a large patient subset.  This report presents the accuracy data from a consecutive series of 599 patients having a total of 2438 pedicle screws placed using 3-D image guidance.  To the authors’ best knowledge, this represents the largest single operator study of its kind. Materials & Methods The surgical procedures consisted of either a minimally invasive TLIF or a mini-open PLIF, performed over an 8-year period.  All lumbar pedicle screws were placed percutaneously using a 3-D image guided Sextant system (Medtronic, Inc.)  The accuracy of lumbar pedicle screw placement was retrospectively reviewed by a board certified radiologist in 599 patients utilizing post-operative CT scans with axial, coronal and sagittal images.  Pedicle breaches, when present, were recorded by distance of breach outside the pedicle (in mm) and direction of breach (medial, lateral, superior or inferior).  A total of 2107 pedicle screws were evaluated (86.4%). Results Out of 2107 pedicle screws there were 7 breaches.  5 were 3-4 mm and 2 were 1-2mm (5 medial, 2 lateral).  Only one patient out of 599 required postoperative screw revision due to a clinically symptomatic breach.  The breach rate was 0.3% (7 in 2107).  The clinically symptomatic breach rate was 1 in 2438 screws (0.04%). Conclusion Intraoperative fluoroscopic systems that produce multiplanar CT-like imaging combined with computerized image guidance systems (IGS), provide a highly accurate minimally invasive technique for the percutaneous placement of lumbar pedicle screws.  The presentation will include a focused discussion of the instrumentation and surgical techniques utilized in pedicle screw placement and provide practical insight for interpretation of post-operative lumbar spine CT exams. References 1. Arand M, Hassfeld S, Kinzl L, et al.  “Spinal navigation in cervical fractures - a preliminary clinical study on Judet-osteosynthesis of the axis.” Comp Aid Surg; (2001) 6:170–175. 2. Laine, T, Lund T, Ylikoski M.  “Accuracy of pedicle screw insertion with and without computer assistance: a randomized controlled clinical study in 100 consecutive patients.” Eur Spine J 9(3) 2000: 235–240. 3. Lavallee S, Sautot P, Troccaz J, et al. “Computer-assisted spine surgery: a technique for accurate transpedicular screw fixation using CT data and a 3-D optical localizer.” J.Image Guid.Surg; (1995) 1:65–73 4. Nolte L, Zamorano L, Arm E, et al.  “Image-guided computer-assisted spine surgery: a pilot study on pedicle screw fixation.” Stereotact.Funct.Neurosurg; (1996) 66:108–117. 5. Weidner, A, Wahler M, Chiu S Modification of C1-C2 transarticular screw fixation by image-guided surgery. Spine 25(20): 2668–2673:108–117.