| ObjectiveTo design patient-specific, thoracic multi-level navigational templates, and applying the templates in models and surgeries, to evaluate its accuracy, safety and stability in assisting pedicle screw placement.MethodsTwenty cases who needed thoracic surgeries from January 2015 to December 2016 were divided into two groups, with ten cases each: one group-the control group,used the traditional freehand pedicle fixation method.and the other group-the experiment group, used digital navigational templates assisted fixation. After CT scan of the ten cases in the experiment group, the original data were made for digital reconstruction, mocking pedicle screw placement,and designing multi-level navigational templates by the software of Mimics 17.0 and 3-Matic 9.0. Then created the thoracic model and multi-level navigational templates using laser rapid prototyping,and tested their stability and accuracy in vitro and in vivo experiments. Then applying the multi-level navigational templates in thoracic surgeries of the experiment group, with each operation time, blood lose, and adverse reactions related to the screw placement recorded. After postoperative CT scans, observed the screw position, graded them, and evaluate the accuracy of multi-level navigational templates assisted placement. Then compared, analyzed and discussed the above data with that of the ten cases in the control group, with freehand fixations.ResultsThe experimental group included four cases with scoliosis, two cases with thoracic tuberculosis, and four cases with thoracic spinal stenosis; four cases are male and six female, with an average age of 32.7, ranging from 11 to 51.The control group included four cases with scoliosis, two cases with thoracic tuberculosis, and four cases with thoracic spinal stenosis; five cases are male and five female, with an average age of 33.9, ranging from 12 to 55.For the experiment group, ten sets of spinal models were reconstructed and created for the surgery, thirty two multi-level navigational templates were designed and created, with each case cost an average of 7.6 hours in designing templates, ranging from 4.5 to 15 hours. The creation of spinal models and navigation templates cost an average of 4.2 hours, ranging from 3 to 5 hours. In vitro experiments showed that the multi-level navigational templates fusion with the spinal models stably and firmly, and the drill channels were all within pedicle part of the spinal model. A total of 103 pedicle screws were inserted for the experiment group, among which 84 screws (81.6%)were grade 0, 17(16.5%)grade 1,2(1.9%) grade 2, and 0(0%) grade 3 ones; 19 perforated screws(18.4%)(include grade 1, grade 2 and grade 3). In sum, 101(98.1%)out of the 103 screws were acceptable(grade 0 and grade 1 screws),while another two(1.9%)were unacceptable ones (grade 2 and grade 3 screws). Among the experiment group, 55 screws were inserted for the scoliosis cases, with 43 screws(78.2%)were grade 0, 11(20.0%) grade 1,1(1.8%) grade 2,and 0(0%)grade 3 ones;12 perforated screws(21.8%)(include grade 1, grade 2 and grade 3).In sum, 54(98.2%)out of the 55 screws were acceptable(grade 0 and grade 1 screws), and one screw(1.8%)were unacceptable ones(grade 2 and grade 3 screws). Besides, 48 screws were inserted for the thoracic tuberculosis, and thoracic spinal stenosis cases, with 41 screws(85.4%)were grade 0, 6(12.5%)grade 1,1(2.1%) grade 2,and 0(0%) grade 3 ones ;7 perforated screws(14.6%)(include grade 1, grade 2 and grade 3). In sum, 47(97.9%)out of the 48 screws were acceptable (grade 0 and grade 1 screws),and one screw(2.1%)were unacceptable ones(grade 2 and grade 3 screws).As for the control group, a total of 96 pedicle screws were inserted, among which 60 screws(62.5%)were grade 0, 22(22.9%) grade 1,9(9.4%) grade 2,and 5(5.2%) grade 3 ones;36 perforated screws(37.5%)(include grade 1, grade 2 and grade 3). In sum, 82(85.4%) out of the 96 screws were acceptable (grade 0 and grade 1 screws),while another 14(14.6%)were unacceptable ones(grade 2 and grade 3 screws). Among the control group, 48 screws were inserted for the scoliosis cases, with 28 screws(58.3%)were grade 0, 14(29.2%) grade 1,3(6.3%)grade 2,and 3(6.3%) grade 3 ones;20 perforated screws(41.7%)(include grade 1,grade 2 and grade 3). In sum, 42(87.5%)out of the 48 screws were acceptable(grade 0 and grade 1 screws), and 6 screws(12.5%)were unacceptable ones(grade 2 and grade 3 screws). Besides, 48 screws were inserted for the thoracic tuberculosis, and thoracic spinal stenosis cases, with 32 screws(66.7%)were grade 0, 8(16.7%) grade 1,6(12.5%) grade 2,and 2(4.2%)grade 3 ones;16 perforated screws(33.3%)(include grade 1, grade 2 and grade 3).In sum, 40(83.3%) out of the 48 screws were acceptable (grade 0 and grade 1 screws), and 8 screws(16.7%)were unacceptable ones(grade 2 and grade 3 screws).The experiment group showed statistically difference (P < 0.05) in the screw grading, perforated screws ratio and accuracy rate for setting thoracic pedicle screws, compared with the control group. Moreover, the experiment group,including scoliosis, thoracic tuberculosis, and thoracic spinal stenosis cases,showed statistically difference (P < 0.05) in the screw grading, perforated screws ratio and accuracy rate for setting thoracic pedicle screws, compared with the control group. While there were no statistically difference(P > 0.05)between the two groups in operation time and blood lose, with operation time of 136.0±26.3 minutes for the experiment group vs.control group's 159.0±43.8 minutes,and blood lose of 400±352ml and 395±307ml respectively. There were no surgery relevant complications for patients in the two groups.ConclusionThe above findings suggested that patient-specific,multi-level navigational templates for thoracic pedicle screw placement is a safe and efficient method,showing its advantages in high stability, high accuracy and good applicability. |
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