PMID- 34421433
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20220716
IS  - 1556-3316 (Print)
IS  - 1556-3324 (Electronic)
IS  - 1556-3316 (Linking)
VI  - 17
IP  - 2
DP  - 2021 Jul
TI  - Design, Fabrication, and Accuracy of a Novel Noncovering Lock-Mechanism Bilateral 
      Patient-Specific Drill Guide Template for Nondeformed and Deformed Thoracic 
      Spines.
PG  - 213-222
LID - 10.1177/1556331621996331 [doi]
AB  - Background: Pedicle screw (PS) placement has been widely used in fusion surgeries 
      on the thoracic spine. Achieving cost-effective yet accurate placements through 
      nonradiation techniques remains challenging. Questions/Purposes: Novel 
      noncovering lock-mechanism bilateral vertebra-specific drill guides for PS 
      placement were designed/fabricated, and their accuracy for both nondeformed and 
      deformed thoracic spines was tested. Methods: One nondeformed and 1 severe 
      scoliosis human thoracic spine underwent computed tomographic (CT) scanning, and 
      2 identical proportions of each were 3-dimensional (3D) printed. Pedicle-specific 
      optimal (no perforation) drilling trajectories were determined on the CT images 
      based on the entry point/orientation/diameter/length of each PS. 
      Vertebra-specific templates were designed and 3D printed, assuring minimal yet 
      firm contacts with the vertebrae through a noncovering lock mechanism. One model 
      of each patient was drilled using the freehand and one using the template guides 
      (96 pedicle drillings). Postoperative CT scans from the models with the inserted 
      PSs were obtained and superimposed on the preoperative planned models to evaluate 
      deviations of the PSs. Results: All templates fitted their corresponding vertebra 
      during the simulated operations. As compared with the freehand approach, PS 
      placement deviations from their preplanned positions were significantly reduced: 
      for the nonscoliosis model, from 2.4 to 0.9 mm for the entry point, 5.0 degrees  to 3.3 degrees  
      for the transverse plane angle, 7.1 degrees  to 2.2 degrees  for the sagittal plane angle, and 
      8.5 degrees  to 4.1 degrees  for the 3D angle, improving the success rate from 71.7% to 93.5%. 
      Conclusions: These guides are valuable, as the accurate PS trajectory could be 
      customized preoperatively to match the patients' unique anatomy. In vivo studies 
      will be required to validate this approach.
CI  - (c) The Author(s) 2021.
FAU - Ashouri-Sanjani, Mehran
AU  - Ashouri-Sanjani M
AD  - Department of Mechanical Engineering, Sharif University of Technology, Tehran, 
      Iran.
FAU - Mohammadi-Moghadam, Shima
AU  - Mohammadi-Moghadam S
AD  - Department of Mechanical Engineering, Sharif University of Technology, Tehran, 
      Iran.
FAU - Azimi, Parisa
AU  - Azimi P
AD  - Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, 
      Tehran, Iran.
FAU - Arjmand, Navid
AU  - Arjmand N
AD  - Department of Mechanical Engineering, Sharif University of Technology, Tehran, 
      Iran.
LA  - eng
PT  - Journal Article
DEP - 20210304
PL  - United States
TA  - HSS J
JT  - HSS journal : the musculoskeletal journal of Hospital for Special Surgery
JID - 101273938
PMC - PMC8361592
OTO - NOTNLM
OT  - 3D printing
OT  - drilling
OT  - fusion surgery
OT  - pedicle screws
OT  - template guides
OT  - thoracic spine
COIS- Declaration of Conflicting Interests: The author(s) declared no potential 
      conflicts of interest with respect to the research, authorship, and/or 
      publication of this article.
EDAT- 2021/08/24 06:00
MHDA- 2021/08/24 06:01
PMCR- 2022/07/01
CRDT- 2021/08/23 06:24
PHST- 2020/11/03 00:00 [received]
PHST- 2020/12/11 00:00 [accepted]
PHST- 2021/08/23 06:24 [entrez]
PHST- 2021/08/24 06:00 [pubmed]
PHST- 2021/08/24 06:01 [medline]
PHST- 2022/07/01 00:00 [pmc-release]
AID - 10.1177_1556331621996331 [pii]
AID - 10.1177/1556331621996331 [doi]
PST - ppublish
SO  - HSS J. 2021 Jul;17(2):213-222. doi: 10.1177/1556331621996331. Epub 2021 Mar 4.