TY - JOUR
T1 - End Vertebra Versus Apical Vertebra
T2 - Where Are We More Likely to Misplace in Spine Deformity?
AU - Sarwahi, Vishal
AU - Wendolowski, Stephen F.
AU - Lo, Yungtai
AU - Thornhill, Beverly
AU - Amaral, Terry
N1 - Publisher Copyright:
© 2017 Wolters Kluwer Health, Inc. All rights reserved.
PY - 2020/2/1
Y1 - 2020/2/1
N2 - Background Data:Pedicle screws placement remains technically demanding. The thoracic curve apex is considerably difficult due to its unique morphology and severe rotation. In comparison the upper end vertebrae have smaller pedicles and limited soft tissue exposure. This study seeks to evaluate the likelihood of screw misplacement at the end vertebra and apex.Methods:A retrospective review of preoperative and postoperative computed tomographic (CT) scans of spinal deformity patients who underwent posterior spinal fusion with pedicle screw constructs between 2004 and 2011 was performed. Pedicles located at the upper instrumented vertebra (UIV) and lower instrumented vertebra (LIV), and the major and minor apices were evaluated. Pedicle morphology was studied on preoperative CT and screw placement on postoperative CT.Results:In total, 188 patients met the inclusion criteria, 172 had preoperative CT scans and 133 had postoperative CT scans. The UIV had a significantly lower percentage of normal pedicles (type A) compared with apex major, apex minor, or LIV (59.1% vs. 76.1% vs. 77.3% vs. 98.7%; P<0.001). UIV had significantly the lowest percentage of normal normally placed screws compared with LIV, apex major, or apex minor (69.4% vs. 97.3% vs. 87.6% vs. 92.1%; P<0.001). In a logistic regression adjusted for preoperative Cobb angles, UIV was more likely to have screws misplaced (odds ratio =7.56; 95% confidence interval, 4.01-14.30; P<0.001) and abnormal pedicles (odds ratio=2.81; 95% confidence interval, 1.52-5.19; P=0.001) compared with any other location studied. In abnormal pedicles, 41 (39.8%) of the 103 UIV screws were misplaced, whereas 10 (16.4%) of the 61 apex major, apex minor, or LIV screws were misplaced (P=0.007).Conclusions:The UIV presents more of a risk for pedicle screw misplacement and abnormal morphology when compared with LIV and apical vertebra. We believe these findings can aid in the surgeon's preoperative and intraoperative management to ensure increased success in accurate and safe pedicle screw placement.
AB - Background Data:Pedicle screws placement remains technically demanding. The thoracic curve apex is considerably difficult due to its unique morphology and severe rotation. In comparison the upper end vertebrae have smaller pedicles and limited soft tissue exposure. This study seeks to evaluate the likelihood of screw misplacement at the end vertebra and apex.Methods:A retrospective review of preoperative and postoperative computed tomographic (CT) scans of spinal deformity patients who underwent posterior spinal fusion with pedicle screw constructs between 2004 and 2011 was performed. Pedicles located at the upper instrumented vertebra (UIV) and lower instrumented vertebra (LIV), and the major and minor apices were evaluated. Pedicle morphology was studied on preoperative CT and screw placement on postoperative CT.Results:In total, 188 patients met the inclusion criteria, 172 had preoperative CT scans and 133 had postoperative CT scans. The UIV had a significantly lower percentage of normal pedicles (type A) compared with apex major, apex minor, or LIV (59.1% vs. 76.1% vs. 77.3% vs. 98.7%; P<0.001). UIV had significantly the lowest percentage of normal normally placed screws compared with LIV, apex major, or apex minor (69.4% vs. 97.3% vs. 87.6% vs. 92.1%; P<0.001). In a logistic regression adjusted for preoperative Cobb angles, UIV was more likely to have screws misplaced (odds ratio =7.56; 95% confidence interval, 4.01-14.30; P<0.001) and abnormal pedicles (odds ratio=2.81; 95% confidence interval, 1.52-5.19; P=0.001) compared with any other location studied. In abnormal pedicles, 41 (39.8%) of the 103 UIV screws were misplaced, whereas 10 (16.4%) of the 61 apex major, apex minor, or LIV screws were misplaced (P=0.007).Conclusions:The UIV presents more of a risk for pedicle screw misplacement and abnormal morphology when compared with LIV and apical vertebra. We believe these findings can aid in the surgeon's preoperative and intraoperative management to ensure increased success in accurate and safe pedicle screw placement.
KW - UIV
KW - apex
KW - kyphosis
KW - misplaced screws
KW - pedicle screw misplacements
KW - pedicle screws
KW - scoliosis
KW - spinal deformity
KW - spine
KW - upper instrumented vertebral
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U2 - 10.1097/BPO.0000000000001102
DO - 10.1097/BPO.0000000000001102
M3 - Article
C2 - 31923163
AN - SCOPUS:85077765576
SN - 0271-6798
VL - 40
SP - 53
EP - 59
JO - Journal of Pediatric Orthopaedics
JF - Journal of Pediatric Orthopaedics
IS - 2
ER -