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. 2022 Nov 8;22(1):384.
doi: 10.1186/s12893-022-01829-z.

Cortical screw placement with a spinous process clamp guide: a cadaver study accessing accuracy

Xi-Nuo Zhang #  1 , Yi-Qi Zhang #  1 , Yu-Zeng Liu  1 , Qing-Jun Su  1 , Li Guan  1 , Dong-Yue Li  1 , Bao-Qing Pei  2 , Ai-Xing Pan  1 , Hong-Hao Yang  1 , Hong-Tao Ding  1 , Yong Hai  3 , Li-Jin Zhou  4
Affiliations

Cortical screw placement with a spinous process clamp guide: a cadaver study accessing accuracy

Xi-Nuo Zhang et al. BMC Surg. .

Abstract

Background and objective: The Cortical Bone Trajectory (CBT) technique provides an alternative method for fixation in the lumbar spine in patients with osteoporosis. An accuracy CBT screw placement could improve mechanical stability and reduce complication rates.

Purpose: The purpose of this study is to explore the accuracy of cortical screw placement with the application of implanted spinous process clip (SPC) guide.

Methods and materials: Four lumbar specimens with T12-S1 were used to access the accuracy of the cortical screw. The SPC-guided planning screws were compared to the actual inserted screws by superimposing the vertebrae and screws preoperative and postoperative CT scans. According to preoperative planning, the SPC guide was adjusted to the appropriate posture to allow the K-wire drilling along the planned trajectory. Pre and postoperative 3D-CT reconstructions was used to evaluate the screw accuracy according to Gertzbein and Robbins classification. Intraclass correlation coefficients (ICCs) and Bland-Altman plots were used to examine SPC-guided agreements for CBT screw placement.

Results: A total of 48 screws were documented in the study. Clinically acceptable trajectory (grades A and B) was accessed in 100% of 48 screws in the planning screws group, and 93.8% of 48 screws in the inserted screws group (p = 0.242). The incidence of proximal facet joint violation (FJV) in the planning screws group (2.1%) was comparable to the inserted screws group (6.3%) (p = 0.617). The lateral angle and cranial angle of the planned screws (9.2 ± 1.8° and 22.8 ± 5.6°) were similar to inserted screws (9.1 ± 1.7° and 23.0 ± 5.1°, p = 0.662 and p = 0.760). Reliability evaluated by intraclass correlation coefficients and Bland-Altman showed good consistency in cranial angle and excellent results in lateral angle and distance of screw tip.

Conclusions: Compared with preoperative planning screws and the actually inserted screws, the SPC guide could achieve reliable execution for cortical screw placement.

Keywords: Cadaveric study; Cortical bone trajectory; Guide; Lumbar spine fixation; Navigation.

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Conflict of interest statement

The study was conducted under the cooperation of the Orthopedic Department of Beijing Chaoyang Hospital, Peking Union Medical College, and Beihang University. The authors have no conflicts of interest to disclose in relation to this article.

Figures

Fig. 1
Fig. 1
A the measurement parameters of SPC guide; B cranial angle of the planned screws guided with SPC; C lateral angle of the planned screws guided with SPC; D distance between screw tip measured in preoperative spine 3D reconstructions
Fig. 2
Fig. 2
A Hardware of SPC guide; B the SPC guide was anchored on the specimen in sagittal view; C the SPC guide was anchored on the specimen in coronal view; D the SPC guide was anchored on the specimen in post-lateral view
Fig. 3
Fig. 3
A The SPC guide was anchored on the specimen in anteroposterior imaging; B the SPC guide was anchored on the specimen in sagittal imaging
Fig. 4
Fig. 4
A CT scan location image; B the first layer of 1.5 mm K-wires in L4 vertebrae; C the second layer of 1.5 mm K-wires in L4 vertebrae and pedicle; D the third layer of 1.5 mm K-wires in L4 pedicle
Fig. 5
Fig. 5
Bland–Altman Plots (95% limits of agreement) for planning screw in 3D reconstructions spine and inserted screw with SPC guide in lumbar specimens for (A) lateral angle, (B) cranial angle and (C) distance of screw tips
See this image and copyright information in PMC

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