Deviation Analysis of Atlantoaxial Pedicle Screws Assisted by a Drill Template

Autor: Todd J. Albert, Zhen Shan Yuan, Christopher K. Kepler, Hui Xie, Jian Bing Yuan, Yong Hu, Wei Xin Dong, Cheng Tao Wang
Rok vydání: 2014
Předmět:
Zdroj: Orthopedics. 37
ISSN: 1938-2367
0147-7447
Popis: Although C1–C2 pedicle screw fixation provides an excellent fusion rate and rigid fixation, this technique has a potential risk. It is essential to develop an accurate screwing method to avoid this neurovascular injury. To develop and validate the accuracy of a novel navigational template for C1–C2 pedicle screw placement in cadaveric specimens, computed tomography scans with 1-mm-wide cuts were obtained of 32 cadaveric cervical specimens. The authors developed 64 three-dimensional full-scale templates that were created by computer modeling with a rapid prototyping technique from the computed tomography data. Drill templates were constructed with a custom trajectory for each level and side. The drill templates were used to guide the establishment of a pilot hole for screw placement. The average distances between ideal and actual entry points of the C1 pedicle screws in the x, y, and z axes were 0.16±0.46 mm, 0.11±0.52 mm, and −0.01±0.54 mm, respectively, on the left side and 0.11±0.49 mm, 0.01±0.56 mm, and −0.09±0.59 mm, respectively, on the right side. The average distances between ideal and actual entry points of the C2 pedicle screws in the x, y, and z axes were 0.05±0.54 mm, 0.20±0.59 mm, and −0.06±0.58 mm, respectively, on the left side and 0.17±0.55 mm, 0.1±0.58 mm, and −0.01±0.49 mm, respectively, on the right side. Factors related to human error and imprecision are responsible for most malpositioning of instrumentation. The rapid prototyping drill template for C1–C2 screw placement is described to minimize human error, although it introduces error related to computer software and variation in manufacturing.
Databáze: OpenAIRE
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