An innovative self-stabilised 3D-printed artificial vertebral body designed for clinical application and comparison...

Corpectomy and bone defects reconstruction is a key surgical technique in spinal diseases treatment. Popular bone defect reconstruction methods include titanium mesh cage (TMC) fixation plate systems and traditional 3D-printed artificial vertebral body (3D-AVB). In our previous study, we conceptualised and created a self-stabilised 3D-printed artificial vertebral body (3D-SAVB) system and tested its clinical safety and efficacy, but have not compared with the conventional implants. This study was designed to compare our innovative 3D-SAVB system with a conventional 3D-AVB system, both mechanically and clinically.

This study included 33 patients with cervical spondylotic myelopathy who underwent single-level ACCF using the TMC, 3D-AVB, and 3D-SAVB systems. The operation time, intraoperative blood loss, neurological function recovery rate, average subsidence length, and cervical lordosis correction (C2-7 Cobb angle change) rates of the TMC, 3D-AVB, and 3D-SAVB groups were tested to compare their performance, and we selected four representative clinical cases with various diseases who underwent 3D-SAVB surgery for follow-up studies to demonstrate the clinical effect. In addition, finite element analysis was used to compare the stability, stress distribution, and artificial vertebral body stress of the 3D-SAVB, 3D-AVB, and TMC systems.

The neurological function recovery rates of the TMC (84.8 ± 10.7 %), 3D-AVB (74.3 ± 7.9 %), and SAVB (85.99 ± 13.2 %) groups showed no significant difference (p > 0.05). The mean operation time of the TMC group (119.3 ± 21.5 min) is significant more than the 3D-SAVB (76.1 ± 23.1 mm) and 3D-AVB (82.6 ± 21.3 mm) groups (p < 0.05). The intraoperative blood loss of the TMC group (218.2 ± 51.5 ml) was significantly greater than that of the 3D-SAVB (187.6 ± 43.2 ml) and 3D-AVB groups (195.6 ± 31.3 ml) (p < 0.05). The mean subsidence length of the TMC group (3.5 ± 0.6 mm) was significantly greater than the 3D-AVB (1.3 ± 0.5 mm, p < 0.001) and 3D-SAVB (1.2 ± 1.1 mm, p = 0.002). The lordosis correction (C2-7 Cobb angle change) rate of the 3D-SAVB [(60.38 ± 6.2)%] and 3D-AVB [(61.4 ± 7.9)%] groups was significantly higher than that of the TMC group [(32.35 ± 3.7)%] (p < 0.05). Patients treated with the 3D-SAVB system achieved satisfactory treatment results with no postoperative complications during the follow-up period. The failed TMC fixation plate system underwent revision surgery using 3D-SAVB and demonstrated a superior prognosis. The biomechanical test showed that the 3D-SAVB system had greater longitudinal stability (p < 0.01), better stress distribution (p < 0.01), and less vertebral stress (p < 0.01) than the 3D-AVB and TMC systems.

These results demonstrate the mechanical advantages and great clinical application potential of our innovative 3D-SAVB system for challenging spinal surgeries.

The 3D-SAVB system eliminates the need for supplementary fixation plates, reduces surgical complications like subsidence, and improves cervical lordosis correction. Its biomechanical superiority and clinical efficacy support its adoption as a next-generation spinal implant.