Objective: To compare the effectiveness and imaging features between implanting single and double Cage into intervertebral body through unilateral transforaminal lumbar interbody fusion (TLIF).
Methods: The clinical data were collected and analyzed from 104 patients who underwent unilateral TLIF between January 2013 and October 2014, who were divided into 2 groups: single Cage was implanted into intervertebral body in 64 cases (76 segments) in traditional group, and double Cage was implanted into intervertebral body in 56 cases (70 segments) in reformative group. There was no significant difference in age, gender, bone mineral density, operation segments between 2 groups (P > 0.05). The visual analogue scale (VAS), Oswestry disability index (ODI), and Japanese Orthopedic Association (JOA) scores were used to evaluate the effectiveness; the area of intervertebral bone-graft, fusion rate, height of intervertebral space, and the number of Cage subsidence were measured by CT scan.
Results: All the patients were followed up 12.85 months on average (range, 9-15 months). The VAS, ODI, and JOA scores were significantly improved at each time point after operation when compared with preoperative values (P < 0.05), and no significant difference was found between 2 groups (P > 0.05) except VAS and ODI at 12 months after operation (P < 0.05). However, the area of intervertebral bone-graft in reformative group [(5.94 ± 1.17) cm2] was significantly larger than that in traditional group [(4.81± 0.97) cm2] at 7 days after operation (t = -6.365, P = 0.000). At 3 and 12 months after operation, the fusion rate was respectively 84.2% and 92.1% in traditional group and was respectively 88.6% and 94.3% in reformative group. Although the height of intervertebral space were increased when compared with preoperative height, the incidence rates of Cages subsidence in traditional group were 44.74% and 47.37% respectively at 3 and 12 months after operation and were significantly higher those that in reformative group (11.43% and 14.29% respectively) (P < 0.05). In addition, the height difference between affected side and normal side in traditional group was significantly larger than that in reformative group (P < 0.05).
Conclusion: Both single and double Cage implanted into the intervertebral body through unilateral TLIF have good effectiveness. However, double Cage implanted into intervertebral body may hold the height of intervertebral space, reduce the incident rate of Cage subsidence, and prevent sagittal imbalance.