Three-dimensional printed artificial vertebral body versus titanium mesh cage and nanohydroxyapatite/polyamide-66 cage in anterior cervical corpectomy and fusion: a retrospective cohort study with a minimum 5-year follow-up.

backgroundAnterior cervical corpectomy and fusion (ACCF) is a commonly performed procedure for cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL), but the choice of reconstructive device after corpectomy remains unsettled. Titanium mesh cages (TMCs) and nanohydroxyapatite/polyamide-66 (n-HA/PA66) cages are both widely used in clinical practice, although subsidence and postoperative loss of cervical alignment remain important concerns. Three-dimensional printed artificial vertebral bodies (3DP-AVBs) have been introduced as an alternative reconstructive option. This study assessed the long-term radiographic and clinical outcomes of 3DP-AVB, n-HA/PA66, and TMC reconstruction after single-level ACCF.

methodsThis retrospective cohort study included 101 patients with CSM or OPLL who underwent single-level ACCF at two centres. Reconstruction was performed using a 3DP-AVB (n = 33), an n-HA/PA66 cage (n = 34), or a TMC (n = 34). Clinical and radiographic data were reviewed with a minimum follow-up of 5 years. Radiographic outcomes included fusion status, subsidence, fused segment height (FSH), and cervical sagittal alignment. Clinical outcomes included the Visual Analog Scale (VAS), Japanese Orthopaedic Association (JOA) score, and Neck Disability Index (NDI). Complications and revision procedures were also recorded.

resultsAt final follow-up, the 3DP-AVB group had less loss of FSH than the n-HA/PA66 and TMC groups (1.99 ± 0.73 vs. 2.80 ± 0.70 vs. 3.07 ± 0.81 mm; P < 0.001) and better preservation of cervical sagittal alignment (C2-7 Cobb angle, 19.47 ± 3.31° vs. 15.19 ± 3.25° vs. 15.75 ± 3.54°; P < 0.001). The unweighted subsidence rate was lower in the 3DP-AVB group (15.2% vs. 32.4% vs. 44.1%; P= 0.036), whereas IPTW-weighted analysis showed a numerically lower but nonsignificant trend (17.9% vs. 35.7% vs. 45.8%; P = 0.067). Fusion was achieved in all patients by 12 months. All three groups improved after surgery. Differences in JOA and NDI were observed at 3 months and remained significant at final follow-up (final JOA, 15.09 ± 1.28 vs. 13.59 ± 1.37 vs. 13.53 ± 1.44; final NDI, 10.03 ± 1.57 vs. 11.88 ± 1.45 vs. 11.88 ± 1.61; both  P < 0.001). VAS scores were similar among groups.

conclusionsIn patients undergoing single-level ACCF, 3DP-AVB reconstruction was associated with better preservation of fused segment height and cervical sagittal alignment during long-term follow-up than n-HA/PA66 or TMC reconstruction. Although subsidence was less frequent in the 3DP-AVB group in the unweighted analysis, the IPTW-weighted comparison showed only a nonsignificant trend and should be interpreted cautiously. All three reconstructive methods achieved fusion and postoperative clinical improvement. Compared with the other two implants, 3DP-AVB may provide greater radiographic durability. Although JOA and NDI scores were statistically more favorable in the 3DP-AVB group, the clinical relevance of these differences should be interpreted cautiously.