Transpedicular implantation using a two-part navigation template in extremely small pedicles

Objective. To explore results of transpedicular screws insertion in extremely small pedicles using two-part navigation template. Material and Methods. Eleven consecutive patients with spinal deformities were included in the study. During surgery pedicle screws were implanted using two-part navigation templates with metallic adapter that allow to guide screw insertion as well as pedicle drilling (total of 98 screws including 60 screws in pedicle width lesser than 3.5 mm). Retrospective control group consisted of 46 patients treated using common design navigation templates that guide pedicle drilling only (total of 294 screws including 106 screws in pedicle width lesser than 3.5 mm). Malpositions with “empty” correct transpedicular channel and without one were reported separately. Results. In extremely small pedicles malposition without “empty” transpedicular channel (due to navigation template misplacement) rates were similar in both groups (8.3 % vs. 8.5 %; p > 0.05). Meanwhile malposition with “empty” transpedicular channel (because of secondary screw deviation) rate was significantly less in two-part template group than in common design template group (3.6 % vs. 17.5 %; p < 0.05). Conclusion. In pedicle width less than 3.5 mm application of two-part navigation template guiding transpedicular channel drilling and screw insertion allows to reduce the rate of malposition due to secondary screw deviation significantly, while the difference in malposition rate because of template misplacement is insignificant as compared with navigation template of common design.