A comparative study on the accuracy of pedicle screw placement assisted by personalized rapid prototyping template between pre- and post-operation in patients with relatively normal mid-upper thoracic spine.

Hu, Yong; Yuan, Zhen-shan; Spiker, William; Dong, Wei-xin; Sun, Xiao-yang; Yuan, Jian-bing; Zhang, Jiao; Zhu, Bingke; Spiker, William Ryan

<bold>Purpose: </bold>The aim of this study was to assess the accuracy of rapid prototyping drill template technique for placing pedicle screws in the mid-upper thoracic vertebrae in clinics.<bold>Methods: </bold>151 consecutive patients underwent thoracic instrumentation and fusion for a total of 582 pedicle screws placed in the mid-upper thoracic vertebrae. Using computer software, the authors constructed drill templates that fit onto the posterior elements of the mid-upper thoracic vertebrae with drill guides designed to instrument the pedicles. The start point and three dimensional location of the planned and inserted screws were measured and compared.<bold>Results: </bold>Grading of the CT scans revealed 559 (96.1 %) out of 582 screws completely within the desired pedicle. The direction of pedicle violation included 5 medial, 2 airball, and 16 lateral. The paired t test suggested that these results were statistically significant in more than half of the locations (T1-left-TA(P = 0.024), T2-left-SA(P = 0.031), T3-left-SA(P = 0.014), T4-left-TA(P = 0.004), T5-left-TA(P = 0.034), T7-left-TA(P = 0.000). T1-right-TA(P = 0.049), T2-right-TA(P = 0.044), T3-right-TA(P = 0.014), T5-right-TA(P = 0.013)). The paired t-test suggested that these results were statistically significant at several locations (T4-left-Δy(P = 0.041), T5-left-Δx(P = 0.016), T3-right-Δy(P = 0.015)).<bold>Conclusion: </bold>Use of a rapid prototyping drill template to assist in the placement of mid and upper thoracic pedicle screws may lead to increased accuracy. This patient specific technology must be combined with an understanding of the patients' anatomy and carefully secured to the posterior elements intraoperatively to avoid nerve or vascular complications.

RAPID prototyping; PEDICLE flaps (Surgery); BONE screws; THORACIC vertebrae; SPINAL surgery; SURGERY

European Spine Journal, 2016, Vol 25, Issue 6, p1706

0940-6719

Academic Journal

10.1007/s00586-016-4540-2