Background : Cervical Pedicle Screw(CPS) placement is a challenging work due to high risk of neurovascular complications. Although there have been a number of different free-hand or navigation assisted techniques for CPS placement, perforations always occur during screw insertion, especially lateral perforation. The objective of this research is to describe a novel free-hand technique for subaxial CPS placement (C3–C7) for improving security and decreasing the chances of perforation.
Methods : Thirty-two patients undergoing surgery with CPS instrumentation (C3–C7) at our institute between June 2017 and December 2018 were included in the study. All the patients had cervical trauma, and pedicle screw insertion was made according to the free-hand “slide technique”. Lamina, lateral mass and facet joint of the target area were clearly exposed and the optimal entry point was found on the lateral mass posterior surface. A pedicular probe was then inserted and gently advanced. During the pedicle probe insertion, the cortex of the medial margin of the pedicle acted as a “slide” to permit safe insertion of the screw. If the pedicle screw pathway was intact, screw of appropriate size was carefully placed. Three-dimensional (3D) CT imaging reconstruction was performed in all the patients after surgery, and screw perforations were graded with the Gertzbein-Robbins classification.
Results : A total of 257 CPSs (C3-7) were inserted, of which 41 CPSs in C3, 61 CPSs in C4, 55 CPSs in C5, 53 CPSs in C6, and 47 CPSs in C7. The diameter and length of CPSs were 3.5 mm and 22-26 mm respectively. According to the Gertzbein-Robbins classification, grade 0, 231 screws; grade 1, 19 screws; and grade 2, 7 screws. No neurovascular complications occurred stemming from malpositioning of pedicle screws. In perforated screws (26 screws), lateral perforations were 16, medical perforations were 5, and inferior perforations were 4.
Conclusions : The initial usage result show the “slide technique” is a safe, effective and cost-effective technique for pedicle screw placement in the cervical spine. This is the first report of such technique, we recommend it to wide practical application though further studies are needed.