Reliability of a region-locked 3D-printed template combined with a bi-directional matching scheme to assist screw placement for thoracolumbar fractures

Wenxi ZHANG; Jinhua ZHOU; Hua ZHU; Zhijun QIAO; Bo LIU

ABSTRACT

Objective:

To evaluate the reliability of a region-locked 3D-printed template combined with a bi-directional matching scheme in assistance of screw placement for thoracolumbar fractures.

Methods:

From January 2019 to March 2023, 52 patients with thoracolumbar fracture were treated at Department of Orthopedics, The People's Hospital of Liyang. They were 29 males and 23 females, with an age of (58.2±13.3) years. They were divided into a template group and a free-hand group according to the different screw placements. In the template group of 25 cases, a region-locked 3D-printed template combined with a bi-directional matching scheme was used to assist the pedicle positioning; in the free-hand group of 27 cases, the free hand screw placement was assisted only by image data and C-arm fluoroscopy. The operation time, intraoperative fluoroscopy frequency, intraoperative blood loss, complications, and placement accuracy were compared between the 2 groups. Visual analogue scale (VAS), Oswestry disability index (ODI), and anterior height ratio of the injured vertebra were compared between preoperation, 1 week postoperation, and the final follow-up, as well as between the 2 groups.

Results:

There were no statistically significant differences in the preoperative general data between the 2 groups, showing comparability ( P>0.05). All patients were followed up for (11.2±4.2) months. The differences were not statistically significant between the 2 groups in intraoperative blood loss, rate of complications, VAS or ODI at preoperation, 1 week postoperation, or the final follow-up, or in anterior height ratio of the injured vertebra ( P>0.05). In the template group, the operation time [(80.1±18.5) min] was significantly longer than that in the free-hand group [(69.4±16.6) min], the intraoperative fluoroscopy frequency [2 (2, 3) times] significantly lower than that in the free-hand group [3 (3, 4) times], and the placement accuracy [98.4% (127/129)] significantly higher than that in the free-hand group [91.8% (112/122)] (all P<0.05). All patients showed significant improvements in VAS, ODI and anterior height ratio of the injured vertebra at postoperative 1 week compared with the preoperative values, and the improvements at the last follow-up were significantly larger than those at postoperative 1 week ( P<0.05). No injury to the spinal cord, nerve root or blood vessel was observed postoperatively.

Conclusions:

In the treatment of thoracolumbar fractures, the screw placement assisted by a region-locked 3D-printed template combined with a bi-directional matching scheme is better than free-hand screw placement in terms of improved accuracy and reduced fluoroscopy, but the former incurs longer operative exposure than the latter. There is no significant difference between the 2 methods of screw placement in clinical efficacy.