Chinese Journal Of Clinical Anatomy ›› 2018, Vol. 36 ›› Issue (2): 137-140.doi: 10.13418/j.issn.1001-165x.2018.02.004

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Accuracy of patient-specific drill template cervical pedicle screws insertion via cortical bone trajectory

PENG Peng1, ZHU Mei-song2, ZHANG Xin-tao3, DU Bing-ran1, LI Wen-rui1, LI Jian-y 1,4   

  1. 1. Department of Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Southern Medical University, Guangzhou 510515,China; 2. Department of Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou 510282,China; 3. Department of Image, The Third Affiliated Hospital, Southern Medical University, Guangzhou 510282,China; 4. Nanhai Hospital, Southern Medical University, Foshan 528244,Guangdong Province,China
  • Received:2017-11-14 Online:2018-03-25 Published:2018-05-04

Abstract:

Objective To validate the security and accuracy of cervical pedicle screws insertion (CPSI) with the assistance of patient-specific drill templates (PDTs) via cortical bone trajectory. Methods  Four normal cervical spine specimens(C3~7) were selected and randomly divided into two groups. All specimens received CT scan. After images processing, the individual guide templates with cortical bone trajectory (CBT) were designed and subsequently produced by rapid prototyping (RP) and computer numerical control (CNC) technology, respectively. Then, their security and accuracy were evaluated in facilitating CPSI. Results The absolute deviations at the entry point were (0.28±0.24) mm in group RP and (0.32±0.23) mm in group CNC on the transverse plane, and were (0.30±0.20) mm in group RP and (0.52±0.44) mm in group CNC on the sagittal plane. The absolute deviations at the midpoint of the pedicle were (0.26±0.22) mm in group RP and (0.39±0.32) mm in group CNC on the transverse plane, and were (0.37±0.29) mm in group RP and (0.49±0.50) mm in group CNC on the sagittal plane. For the screw position, 20 screws position were in grade 1 in group RP; 19 screws position were in grade 1 and 1 was in grade 2 in group CNC. No statistically significant difference existed (P>0.05) in deviation and screw position between the two groups. Conclusion CNC-PDTs via cortical bone trajectory are viable in facilitating CPSI with good feasibility and accuracy. It is a new alternative method to lower cervical pedicle insertion.

Key words:  Cortical bone trajectory; CNC; Guide templates; Lower cervical,  Pedicle screws