[CLINICAL APPLICATION OF INDIVIDUALIZED REFERENCE MODEL OF SAGITTAL CURVES AND NAVIGATION TEMPLATES OF PEDICLE SCREW BY THREE-DIMENSIONAL PRINTING TECHNIQUE FOR THORACOLUMBAR FRACTURE WITH DISLOCATION].

OBJECTIVE

To evaluate the clinical significance of individualized reference model of sagittal curves and navigation templates of pedicle screw by three-dimensional printing technique for thoracolumbar fracture with dislocation.

METHODS

Between February 2011 and November 2013, 42 patients with thoracolumbar fracture and dislocation undergoing pedicle screw fixation were divided into 2 groups: traditional pedicle screw internal fixation by fluoroscopy assistant was used in 24 cases (control group), and individualized reference model of sagittal curves and navigation templates of pedicle screw were used in 18 cases (trial group). There was no significant difference in gender, age, injury causes, segment, degree of dislocation, and Frankel classification between 2 groups (P > 0.05). The operation time, intraoperative blood loss, perspective times, and dislocation rate, sagittal angle recovery rate at different time were compared. The success rate of pedicle screw insertion, sagittal screw angle, and Frankel classification were compared. The angle between sagittal screws, difference of screw entry point at horizontal position, and difference of screw inclined angle were compared.

RESULTS

The operating time, intraoperative blood loss, and perspective times in trial group were significantly lower than those in control groups (P < 0.05). All the patients were followed up 12-40 months (mean, 22 months). The dislocation rate at immediate after operation and last follow-up were significantly improved when compared with preoperative value in 2 groups (P < 0.05). At immediate after operation and last follow-up, the dislocation rate and sagittal angle recover rate in trial group were significantly better than those in control group (P < 0.05). There were significant differences in the one-time success rate, final success rate of pedicle screw insertion, and saggital screw angle between 2 groups (χ2 = 9.38, P = 0.00; χ2 = 10.95, P = 0.00; χ2 = 13.43, P = 0.00). The angle between sagittal screws, difference of screw entry point at horizontal position, and difference of screw inclined angle in trail group were significantly less than those in control group (P < 0.05). There was significant difference in the Frankel classification between 2 groups at last follow-up (Z = -1.99, P = 0.04).

CONCLUSION

The application of individualized reference model of sagittal curves and navigation templates of pedicle screw by three-dimensional printing technique for thoracolumbar fracture with dislocation has the advantages of shorter operation time, less intraoperative blood loss, better recovery of thoracolumbar dislocation, and better Frankel classification.