Accuracy of Multilevel Registration in Image-Guided Pedicle Screw Insertion for Adolescent Idiopathic Scoliosis

Abstract

Running Head: Accuracy of Multilevel RegistrationAccuracy of Single-time, Multilevel Registration MINI ABSTRACTAccuracy of multilevel registration for skip pedicle screw placement during image-guided, computer-assisted spine surgery, in adolescent idiopathic scoliosis was assessed. Mean surgical time: 310 min. Pedicle violation observed in only 4/265 screws (1.5%). Mean registration error after point merge: 1.69±0.52: after surface merge 0.51±0.16. Multilevel registration may decrease operative time without compromising accuracy of pedicle screw placement. Accuracy of Multilevel Registration KEY POINTS Multilevel registration employs more than 6 registration points for two, three or four consecutive vertebra to shorten the surgical time.  Pedicle violation was observed in 1.5% of inserted screws.  Multilevel registration may decrease operative time without compromising accuracy of pedicle screw placement afforded by this technique in the setting of adolescent idiopathic scoliosis.  Mean correction rate of skip pedicle screw instrumentation was 66.2%. Accuracy of Multilevel Registration STRUCTURED ABSTRACTStudy Design: Retrospective clinical study. Objective: To assess the accuracy of multilevel registration for skip pedicle screw placement during image-guided, computer-assisted spine surgery, in the setting of adolescent idiopathic scoliosis (AIS). Summary of background data: Computerized frameless stereotactic image-guidance has been used recently to improve pedicle screw placement accurately and safety during spine surgery. Because of possible intervertebral motion and usual difference in patients' position between preoperative imaging and surgery, the imaging model and the surgically exposed spine may be significantly discordant. Consequently, current protocols suggested separate registration of each spinal level (single-level registration) before respective pedicle screw placement, a timeconsuming process. Moreover, although multilevel registration for lumbar spine has been reported, that for thoracic spine has not. Methods: Nineteen patients (1 male, and 18 females; mean age, 13.9 years) with AIS who underwent multilevel registration for skip pedicle screw placement were included. Variables including surgical time, blood loss, preoperative and 2-year post-operative Cobb angle, correction rate, and post-operative screw position by CT image were evaluated. Mean registration error (MRE) after point merge and again after surface merge were recorded for each consecutive vertebra of each case. Results: Mean surgical time was 310 min. (range, 168-420 min.). Mean blood loss 1138 g (range, 300-2300 g). Cobb angle before operation and at 2 years post-operation was 62.4 (43-100) degrees and 21.6 (9-42) degrees, respectively. Mean correction rate 66.2% (39.7-84.5%). Total 265 screws were inserted with CT-based navigation system. Pedicle violation was observed in only 4 screws (1.5%). No neurovascular complication occurred. After point merge, average MRE of all cases was 1.69±0.52mm, and after surface merge was 0.51...

Thoracolumbar instrumentation with CT-guided navigation (O-arm) in 270 consecutive patients: accuracy rates and lessons learned

“…14 However, our experience suggests that perhaps a larger volume of approximately [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] cases is required to demonstrate breach rates similar to those commonly reported in the literature. To our knowledge, the present report is the largest singlecenter series of thoracolumbar PSs placed using the O-arm and the first in the literature to quantify the learning curve for screw accuracy associ ated with this technology.…”

“…1,8 Since IGSS carries a reported mean registration error up to 2-3 mm, any fur ther changes to 3D anatomy subsequent to the registration scan may compromise PS accuracy rates. 17,23 In the present cohort, we did not routinely perform in traoperative CT scanning after hardware placement. This resulted in 4 returns to the operating room over a 54month period for a 1.5% reoperation rate secondary to malposi tioned screws.…”

Optimal surgical care for adolescent idiopathic scoliosis: an international consensus

“…(less complications of pedicle screws, less re-interventions), these studies do not report on cost effectiveness [18][19][20].…”

Reliability of the Planned Pedicle Screw Trajectory versus the Actual Pedicle Screw Trajectory using Intra-operative 3D CT and Image Guidance

“…5,6 Examples of these techniques include the use of anatomic landmarks, 7 laminotomy for palpation of the pedicle, plain radiography, fluoroscopic imaging (standard or image guidance), 8,9 and CT image guidance. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] Extensive literature has been published describing the technique, benefits, and drawbacks of each method, as well as comparisons between different approaches. [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] With its increasing use has come a multitude of studies regarding the safety of this technique.…”