{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,21]],"date-time":"2026-10-21T00:38:39Z","timestamp":1792543119742,"version":"4.5.0"},"reference-count":15,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,10,16]]},"abstract":"<jats:sec>\n                    <jats:title>OBJECTIVE<\/jats:title>\n                    <jats:p>Intraoperative 3D image\u2013guided navigation has improved the accuracy of posterior screw placement in spine surgery. However, discrepancies between planned and achieved screw trajectories remain underexplored. In this study, authors assessed these deviations across spinal regions and their potential correlation with screw misplacement.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>METHODS<\/jats:title>\n                    <jats:p>They prospectively analyzed patients undergoing posterior instrumented fusion surgery between 2021 and 2023. Screw placement accuracy was graded using the 2-mm increment basis of the Gertzbein and Robbins (GR) classification. Additionally, angulation discrepancies between planned and achieved trajectories were measured in the axial and sagittal planes. Statistical analyses included Kruskal-Wallis, Dunn\u2019s post hoc, and Spearman correlation tests.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>RESULTS<\/jats:title>\n                    <jats:p>The study included 725 pedicle and lateral mass screw trajectories in 121 patients. Overall, 95.0% of screws were placed with acceptable accuracy (cervical spine: GR grade A and B; all other spine regions: GR grade A\u2013C). Axial screw trajectory divergence was highest in the subaxial cervical spine (4.2\u00b0 \u00b1 3.0\u00b0), significantly exceeding those in the atlantoaxial (2.6\u00b0 \u00b1 2.1\u00b0), thoracic (2.6\u00b0 \u00b1 2.2\u00b0), and lumbar (2.9\u00b0 \u00b1 3.2\u00b0) regions (p &lt; 0.01). Sagittal divergence was greater in the subaxial cervical spine (4.1\u00b0 \u00b1 4.0\u00b0) than in the thoracic spine (2.8\u00b0 \u00b1 2.7\u00b0; p &lt; 0.001). The correlation between trajectory deviations and screw misplacement was weak or absent.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>CONCLUSIONS<\/jats:title>\n                    <jats:p>Screw trajectory deviations vary by spinal region, with the greatest axial discrepancies observed in the subaxial cervical spine. These findings highlight the importance of recognizing intraoperative navigation limitations and refining surgical techniques to optimize accuracy. Monitoring screw trajectories may enhance training and improve patient safety.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3171\/2026.5.spine2699","type":"journal-article","created":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T00:00:58Z","timestamp":1791936058000},"page":"1-6","source":"Crossref","is-referenced-by-count":0,"title":["Mind the gap: discrepancies between planned and achieved screw trajectories in 3D-navigated spine surgery"],"prefix":"10.3171","author":[{"given":"Ulf","family":"Bertram","sequence":"first","affiliation":[{"name":"Department of Neurosurgery, RWTH Aachen University, Medical Center, Aachen;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Laure","family":"Weis","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, RWTH Aachen University, Medical Center, Aachen;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tobias P.","family":"Schmidt","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, RWTH Aachen University, Medical Center, Aachen;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexander","family":"Romagna","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Muenchen Klinik Bogenhausen, Munich, Germany;"},{"name":"Department of Neurosurgery, University Hospital Salzburg Paracelsus Medical University, Salzburg, Austria; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Miguel","family":"Pishnamaz","sequence":"additional","affiliation":[{"name":"Department of Orthopaedics, Trauma and Reconstructive Surgery, RWTH Aachen University Hospital, Aachen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hans","family":"Clusmann","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, RWTH Aachen University, Medical Center, Aachen;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christian","family":"Blume","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, RWTH Aachen University, Medical Center, Aachen;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christian-Andreas","family":"Mueller","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, RWTH Aachen University, Medical Center, Aachen;"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"key":"b1","series-title":"World Neurosurg","first-page":"e378","article-title":"Intraoperative computed tomography-assisted spinal navigation in dorsal cervical instrumentation: a prospective study on accuracy regarding different pathologies and screw types","volume":"149","author":"Bertram U","year":"2021","unstructured":"Bertram U, Schmidt TP, Clusmann H,  Intraoperative computed tomography-assisted spinal navigation in dorsal cervical instrumentation: a prospective study on accuracy regarding different pathologies and screw types. World Neurosurg. 2021;149:e378\u2013e385. doi:10.1016\/j.wneu.2021.02.014"},{"issue":"2","key":"b2","series-title":"J Neurosurg Spine","first-page":"113","article-title":"Pedicle screw navigation: a systematic review and meta-analysis of perforation risk for computer-navigated versus freehand insertion","volume":"17","author":"Shin BJ","year":"2012","unstructured":"Shin BJ, James AR, Njoku IU, H\u00e4rtl R. Pedicle screw navigation: a systematic review and meta-analysis of perforation risk for computer-navigated versus freehand insertion. J Neurosurg Spine. 2012;17(2):113\u2013122. doi:10.3171\/2012.5.SPINE11399"},{"issue":"3","key":"b3","series-title":"Global Spine J","first-page":"1018","article-title":"Accurate placement and revisions for cervical pedicle screws placed with or without navigation: a systematic review and meta-analysis","volume":"14","author":"Bindels BJJ","year":"2024","unstructured":"Bindels BJJ, Dronkers BEG, Smits MLJ, Verlaan JJ. Accurate placement and revisions for cervical pedicle screws placed with or without navigation: a systematic review and meta-analysis. Global Spine J. 2024;14(3):1018\u20131037. doi:10.1177\/21925682231196456"},{"issue":"9","key":"b4","series-title":"Eur Spine J","first-page":"2937","article-title":"Comparison of major spine navigation platforms based on key performance metrics: a meta-analysis of 16,040 screws","volume":"32","author":"Bonello JP","year":"2023","unstructured":"Bonello JP, Koucheki R, Abbas A,  Comparison of major spine navigation platforms based on key performance metrics: a meta-analysis of 16,040 screws. Eur Spine J. 2023;32(9):2937\u20132948. doi:10.1007\/s00586-023-07865-4"},{"issue":"2_suppl","key":"b5","series-title":"Global Spine J","first-page":"27S","article-title":"Percutaneous posterior cervical pedicle instrumentation (C1 to C7) with navigation guidance: early series of 27 cases","volume":"12","author":"Coric D","year":"2022","unstructured":"Coric D, Rossi V. Percutaneous posterior cervical pedicle instrumentation (C1 to C7) with navigation guidance: early series of 27 cases. Global Spine J. 2022;12(2_suppl):27S\u201333S. doi:10.1177\/21925682211029215"},{"issue":"6","key":"b6","series-title":"J Neurol Surg A Cent Eur Neurosurg","first-page":"537","article-title":"First experience using a new minimally invasive screw-rod system for completely percutaneous pedicle screw fixation of the cervical spine","volume":"86","author":"Scholz C","year":"2025","unstructured":"Scholz C, Hohenhaus M, Hubbe U,  First experience using a new minimally invasive screw-rod system for completely percutaneous pedicle screw fixation of the cervical spine. J Neurol Surg A Cent Eur Neurosurg. 2025;86(6):537\u2013543. doi:10.1055\/a-2479-5742"},{"issue":"1","key":"b7","series-title":"J Spine Surg","first-page":"96","article-title":"A new minimally invasive cervical pedicle screw (CPS) fixation system using intra-operative computed tomography-guided navigation","volume":"11","author":"Blume C","year":"2025","unstructured":"Blume C, Schmidt TP, Mueller CA,  A new minimally invasive cervical pedicle screw (CPS) fixation system using intra-operative computed tomography-guided navigation. J Spine Surg. 2025;11(1):96\u2013103. doi:10.21037\/jss-24-45"},{"issue":"1","key":"b8","series-title":"Nagoya J Med Sci","first-page":"155","article-title":"Trends in the numbers of spine surgeries and spine surgeons over the past 15 years","volume":"84","author":"Kobayashi K","year":"2022","unstructured":"Kobayashi K, Sato K, Kato F,  Trends in the numbers of spine surgeries and spine surgeons over the past 15 years. 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Spine (Phila Pa 1976). 1990;15(1):11\u201314. doi:10.1097\/00007632-199001000-00004"},{"issue":"3","key":"b11","series-title":"J Neurol Surg A Cent Eur Neurosurg","first-page":"191","article-title":"Accuracy of intraoperative computed tomography assisted dorsal instrumentation in spinal revision surgery","volume":"82","author":"Bertram U","year":"2021","unstructured":"Bertram U, Clusmann H, Geiger MF, Riabikin A, Mueller CA, Blume C. Accuracy of intraoperative computed tomography assisted dorsal instrumentation in spinal revision surgery. J Neurol Surg A Cent Eur Neurosurg. 2021;82(3):191\u2013196. doi:10.1055\/s-0040-1721016"},{"key":"b12","series-title":"Statistical Power Analysis for the Behavioral Sciences","author":"Cohen J","year":"1988","unstructured":"Cohen J. Statistical Power Analysis for the Behavioral Sciences. 2nd ed. Lawrence Erlbaum Associates; 1988. 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Medicina (Kaunas). 2022;58(9):1200. doi:10.3390\/medicina58091200"},{"issue":"4","key":"b14","series-title":"J Neurosurg Spine","first-page":"519","article-title":"Three-dimensional assessment of robot-assisted pedicle screw placement accuracy and instrumentation reliability based on a preplanned trajectory","volume":"33","author":"Jiang B","year":"2020","unstructured":"Jiang B, Pennington Z, Zhu A,  Three-dimensional assessment of robot-assisted pedicle screw placement accuracy and instrumentation reliability based on a preplanned trajectory. 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