Individualized 3D printing navigation template for pedicle screw fixation in upper cervical spine

Abstract

PurposePedicle screw fixation in the upper cervical spine is a difficult and high-risk procedure. The screw is difficult to place rapidly and accurately, and can lead to serious injury of spinal cord or vertebral artery. The aim of this study was to design an individualized 3D printing navigation template for pedicle screw fixation in the upper cervical spine.MethodsUsing CT thin slices data, we employed computer software to design the navigation template for pedicle screw fixation in the upper cervical spine (atlas and axis). The upper cervical spine models and navigation templates were produced by 3D printer with equal proportion, two sets for each case. In one set (Test group), pedicle screws fixation were guided by the navigation template; in the second set (Control group), the screws were fixed under fluoroscopy. According to the degree of pedicle cortex perforation and whether the screw needed to be refitted, the fixation effects were divided into 3 types: Type I, screw is fully located within the vertebral pedicle; Type II, degree of pedicle cortex perforation is <1 mm, but with good internal fixation stability and no need to renovate; Type III, degree of pedicle cortex perforation is >1 mm or with the poor internal fixation stability and in need of renovation. Type I and Type II were acceptable placements; Type III placements were unacceptable.ResultsA total of 19 upper cervical spine and 19 navigation templates were printed, and 37 pedicle screws were fixed in each group. Type I screw-placements in the test group totaled 32; Type II totaled 3; and Type III totaled 2; with an acceptable rate of 94.60%. Type I screw placements in the control group totaled 23; Type II totaled 3; and Type III totaled 11, with an acceptable rate of 70.27%. The acceptability rate in test group was higher than the rate in control group. The operation time and fluoroscopic frequency for each screw were decreased, compared with control group.ConclusionThe individualized 3D printing navigation template for pedicle screw fixation is easy and safe, with a high success rate in the upper cervical spine surgery.

Systematic review of 3D printing in spinal surgery: the current state of play

“…A full-scale, stereoscopic understanding of the pathology allows for more detailed planning and simulation of the procedure (10)(11)(12)(13)(14)(15)(16)(17)(18)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(50)(51)(52). Assessing complex pathologies on a model overcomes many of the issues associated with traditional 3D imaging, such as the lack of realistic anatomical representation and the associated complexity of computer-related skills and techniques (10,12).…”

“…The improved visualization and preparation afforded by the use of individualized models has clinical benefits, with reduced operation time and perioperative blood loss being most commonly reported (11,13,14,(21)(22)(23)(26)(27)(28)30). Reduction in operation time of 15-20% has been reported in multiple studies (11,14,23) across various surgical procedures.…”

“…The main reasons given for reduced operation time included a more evolved understanding of the pathology, such as location and surgical approach, and the facilitation of pre-operative instrumentation decisions (14,16,(18)(19)(20)(21)24,27,28,50). Other clinical benefits such as improved diagnosis, reduction in fluoroscopy time, better communication within the surgical team and lower rates of screw misplacement have been reported when compared with the use of conventional imaging in pre-operative planning (11,14,20,26,30). Izatt et al (14) found that the use of a 3DP biomodel improved surgical outcomes in 78% of cases, though this is contradicted by Li et al (23) who reported no change in complication rates or clinical outcomes.…”

“…Guarino et al (13) also found that access issues were not only due to cost, but also a paucity of providers with the equipment and expertise to make the widespread use of this technology commercially viable. The learning curve for the required familiarity with the software has also been reported as a barrier (23,30). As time taken to create the models and the associated costs continue to decline, there should be an increase in the use of this technology in clinical practice.…”

“…The use of intra-operative imaging increases harmful radiation exposure for both doctors and patients (30,(34)(35)(36). 3DP guides may offer an alternative as a simple, convenient, low cost and complexequipment free way to improve the accuracy of pedicle screw placement (30)(31)(32)(33)(34)(35)(36)(37)(39)(40)(41)(42)(43).…”