ObjectiveTo investigate the effectiveness of treatment of locked lower cervical fracture and dislocation with anterior cervical fusion and internal fixation combined with the release of the interlocking facet through the Luschka joint and anterior lamina space.MethodsTwelve patients with lower cervical interlocking fracture and dislocation were analyzed retrospectively between January 2013 and June 2015. There were 7 males and 5 females, aged 25-59 years with an average age of 38.4 years. The disease duration was 9.6 hours to 100 days with an average of 7.3 days. There were 8 cases of unilateral locking and 4 cases of bilateral locking; 4 cases of old injury and 8 cases of fresh injury. The injured segments were 2 cases of C3, 4, 5 cases of C4, 5, 3 cases of C5, 6, and 2 cases of C6, 7. According to Meyerding classification, there were 9 cases of grade Ⅰ and 3 cases of grade Ⅱ. According to the functional classification of American Spinal Injury Association (ASIA), there were 2 cases of grade C, 6 cases of grade D, and 4 cases of grade E. The interlocking facet was released through the Luschka joint and anterior lamina space, and the anterior cervical fusion and internal fixation were used to treat the fracture and dislocation of the lower cervical spine. The recovery of spinal cord function was judged by the functional classification of ASIA; visual analogue scale (VAS) score, neck disability index (NDI) score, modified Japanese Orthopaedic Association (m-JOA) score were used to evaluate the clinical efficacy; the Cobb angle of fusion segment were observed by X-ray film. The intervertebral bone graft fusion was evaluated at 6 months after operation.ResultsThe average operation time was 78.30 minutes, the average intraoperative blood loss was 167.30 mL, and the average postoperative drainage volume was 58.12 mL. No blood transfusion was given during or after operation. During the operation, there was no accidental injury of large blood vessels, esophagus, and trachea; no laryngo edema, dysphagia, hoarseness, and cerebrospinal fluid leakage occurred after operation; no spinal cord injury or nerve root injury aggravated; the incision healed by first intention, and no infection occurred. All 12 cases were followed up 15-20 months, with an average of 16.5 months. The symptoms and function of the nerve injury were significantly improved when compared with that before operation. Re-examination of the cervical spine X-ray film at 6 months after operation showed that the Cage or bone graft was not displaced or broken, the screw was not loosened or detached, and the intervertebral graft fusion rate was up to 100%. At last follow-up, the ASIA grade, Cobb angle of fusion segment, neck pain VAS score, m-JOA score, and NDI score were significantly improved when compared with preoperative one (P<0.05).ConclusionThe effectiveness of treatment of locked lower cervical fracture and dislocation with anterior cervical fusion and internal fixation combined with the release of the interlocking facet through the Luschka joint and anterior lamina space is clear, which not only can make the injured segment get satisfactory reduction, immediate stability and reconstruction, and full decompression, but also can effectively prevent the secondary injury of spinal cord.
Objective To evaluate the deviation between actual and simulated screw placement after cervical pedicle screw placement assisted by 3D printed navigation template, and analyze the correlation between screw placement deviation and navigation pipe length. Methods A total of 40 patients undergoing cervical 1-7 pedicle screw insertion assisted by 3D printed navigation template in Zigong Fourth People’s Hospital between February 2018 and August 2020 were included in this prospective study. These patients were divided into 3 groups randomly, including 12 patients with a 5-mm pipe length (5 mm group), 13 patients with a 10-mm pipe length (10 mm group), and 15 patients with a 15-mm pipe length (15 mm group). Three-dimensional modeling was performed on preoperative cervical CT images of these patients and simulated pedicle screw was placed. Individualized pedicle screw navigation templates were designed according to the position and direction of simulated pedicle screws, and 3D printing was performed on the cervical model and navigation templates. Preoperative 3D printed model and navigation templates were used to simulate the surgical process to confirm the safety of screws. During the operation, pedicle screw placement was performed according to the preoperative design and simulated surgical process. The postoperative CT images were registered with the preoperative CT images in 3D model. The safety of screw placement was evaluated by the postoperative screw placement Grade, and the accuracy of screw placement was evaluated by measuring the deviation of screw placement point and the deviation of screw placement direction in horizontal plane (inclination angle) and sagittal plane (head inclination angle). The influence of different navigation pipe lengths on the safety and accuracy of screw placement was analyzed. Results A total of 164 pedicle screws were inserted with navigation template assistance, including 48 screws (38 in Grade 0 and 10 in Grade 1) in the 5 mm group, 52 screws in the 10 mm group (all in Grade 0), and 64 screws (52 in Grade 0 and 12 in Grade 1) in the 15 mm group, and the difference in the grade among the three groups was statistically significant (P<0.05). When the navigation pipe length was 5, 10, and 15 mm, respectively, the screw entry point deviation was (1.87±0.63), (1.44±0.63), and (1.66±0.54) mm, respectively, the inclination angle deviation was (2.72±0.25), (0.90±0.21), and (1.84±0.35)°, respectively, and the head inclination angle deviation was (8.63±1.83), (7.15±1.38), and (8.24±1.52)°, respectively. The deviations in the 10 mm group were all significantly less than those in the other two groups (P<0.05). Conclusions In the cervical pedicle screw placement assisted by navigation template, all the screws were Grade 0 or Grade 1, with high safety. The mean deviation of the screw entry point is within 2 mm, with high accuracy. When the length of navigation pipe is 10 mm, the safety and accuracy of screw placement can be fully guaranteed.