Accurate pedicle screw placement (PSP) is essential in spinal fusion surgery. Conventional navigation relies on computed tomography (CT) or fluoroscopy, which involves ionizing radiation and requires an error-prone registration procedure. We propose a pipeline that enables PSP planning directly on vertebral point clouds reconstructed from intraoperative RGB-D scans, using the SurgPointTransformer network. The system detects screw entry and pedicle regions, estimates initial trajectories, and refines them via anatomically constrained optimization. We evaluated our method on nine ex-vivo cadaveric specimens, comparing RGB-D–based planning to a CT-based baseline using both RGB-D reconstructions and ground-truth CT meshes. No significant differences were found in entry-point offset (3.53 ± 1.30 mm vs. 3.90 ± 1.29 mm), pedicle-center offset (1.58 ± 0.58 mm vs. 1.68 ± 0.59 mm), trajectory-angle error (7.31 ± 3.34<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="41598_2025_21477_Article_IEq1.gif" Format="GIF" Height="7" Rendition="HTML" Resolution="72" Type="Linedraw" Width="9" /> </InlineMediaObject> <EquationSource Format="TEX">\(^\circ\)</EquationSource> </InlineEquation> vs. 7.67 ± 3.59<InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="41598_2025_21477_Article_IEq1.gif" Format="GIF" Height="7" Rendition="HTML" Resolution="72" Type="Linedraw" Width="9" /> </InlineMediaObject> <EquationSource Format="TEX">\(^\circ\)</EquationSource> </InlineEquation>); all <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="41598_2025_21477_Article_IEq3.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="62" /> </InlineMediaObject> <EquationSource Format="TEX">\(p < 0.05\)</EquationSource> </InlineEquation>. Safety analysis using the Gertzbein–Robbins classification showed 100% radiologically optimal screw placement (grade A) with both methods. PSP planned from RGB–D reconstructions of the exposed dorsal surface alone achieved planning-level accuracy comparable to CT-based planning on the entire vertebral body. Prospective intraoperative validation is required to establish execution accuracy and clinical outcomes.

Feasibility of automatic screw planning via transformer-based shape completion from RGB-D imaging

期刊论文
出版模式：

开放获取
发表日期：

2025年10月28日

查看全文

Aidana Massalimova,
David Bauer,
Nicola Cavalcanti,
Fabio Carrillo,
Farshad Mazda,
Philipp Fuernstahl

摘要

Accurate pedicle screw placement (PSP) is essential in spinal fusion surgery. Conventional navigation relies on computed tomography (CT) or fluoroscopy, which involves ionizing radiation and requires an error-prone registration procedure. We propose a pipeline that enables PSP planning directly on vertebral point clouds reconstructed from intraoperative RGB-D scans, using the SurgPointTransformer network. The system detects screw entry and pedicle regions, estimates initial trajectories, and refines them via anatomically constrained optimization. We evaluated our method on nine ex-vivo cadaveric specimens, comparing RGB-D–based planning to a CT-based baseline using both RGB-D reconstructions and ground-truth CT meshes. No significant differences were found in entry-point offset (3.53 ± 1.30 mm vs. 3.90 ± 1.29 mm), pedicle-center offset (1.58 ± 0.58 mm vs. 1.68 ± 0.59 mm), trajectory-angle error (7.31 ± 3.34 \(^\circ\) vs. 7.67 ± 3.59 \(^\circ\) ); all \(p < 0.05\) . Safety analysis using the Gertzbein–Robbins classification showed 100% radiologically optimal screw placement (grade A) with both methods. PSP planned from RGB–D reconstructions of the exposed dorsal surface alone achieved planning-level accuracy comparable to CT-based planning on the entire vertebral body. Prospective intraoperative validation is required to establish execution accuracy and clinical outcomes.