Comparative Analysis of Radiologic Outcomes Between Polyetheretherketone and Three-Dimensional-Printed Titanium Cages After Transforaminal Lumbar Interbody Fusion.

OBJECTIVE: Transforaminal lumbar interbody fusion (TLIF) is performed worldwide with polyetheretherketone (PEEK) and titanium (Ti) cages for the treatment of degenerative lumbar diseases. The aim of this study was to compare radiologic outcomes between a PEEK and three-dimensional-printed titanium (3DP-Ti) cage after TLIF with >1 year of follow-up. METHODS: A total of 140 patients with degenerative lumbar diseases who underwent TLIF operation were included in this study. Intervertebral disc height and whole lumbar lordosis were measured and evaluated from the preoperative stage to the final follow-up. Subsidence of the cage was indicated if the cage sunk into the adjacent vertebral body or if there was a reduction in height of the fused segment by ≥3 mm during the postoperative follow-up. Migration of the cage was determined as the displacement of the interbody cage by ≥2 mm during the postoperative period. Fusion status was assessed at the 1 year and final follow-up using standard methods. RESULTS: Both disc height and lumbar lordosis were well maintained throughout the study period, and no significant differences were observed between PEEK and 3DP-Ti groups. Both PEEK and 3DP-Ti cages demonstrated low rates of cage subsidence, with no significant difference was noted. A significant cage migration rate was observed in the PEEK group and the revision operation was required for 2 patients. The fusion rate of this study was not found to be statistically significant, although the 3DP-Ti cage was known to have an improved fusion rate than PEEK cage after lumbar interbody fusion. CONCLUSIONS: Radiologic results suggest that the 3DP-Ti cage may be a better interbody cage for TLIF than is the PEEK cage.

A composite of polymethylmethacrylate, hydroxyapatite, and ß-tricalcium phosphate for bone regeneration in an osteoporotic rat model.

The purpose of this study was to test several modifications of the polymethylmethacrylate (PMMA) bone cement by incorporating osteoconductive and biodegradable materials for enhancing bone regeneration capacity in an osteoporotic rat model. Three bio-composites (PHT-1 [80% PMMA, 16% HA, 4% ß-TCP], PHT-2 [70% PMMA, 24% HA, 6% ß-TCP], and PHT-3 [30% PMMA, 56% HA, 14% ß-TCP]) were prepared using different concentrations of PMMA, hydroxyapatite (HA), and ß-tricalcium phosphate (ß-TCP). Their morphological structure was then examined using a scanning electron microscope (SEM) and mechanical properties were determined using a MTS 858 Bionics test machine (MTS, Minneapolis, MN, USA). For in vivo studies, 35 female Wister rats (250 g, 12 weeks of age) were prepared and divided into five groups including a sham group (control), an ovariectomy-induced osteoporosis group (OVX), an OVX with pure PMMA group (PMMA), an OVX with PHT-2 group (PHT-2), and an OVX with PHT-3 group (PHT-3). In vivo bone regeneration efficacy was assessed using micro-CT and histological analysis after injecting the prepared bone cement into the tibial defects of osteoporotic rats. SEM investigation showed that the PHT-3 sample had the highest porosity and roughness among all samples. In comparison to other samples, the PHT-3 exhibited favorable mechanical properties for use in vertebroplasty procedures. Micro-CT and histological analysis of OVX-induced osteoporotic rats revealed that PHT-3 was more effective in regenerating bone and restoring bone density than other samples. This study suggests that the PHT-3 bio-composite can be a promising candidate for treating osteoporosis-related vertebral fractures.

Efficacy of a newly designed helical-shaped 3D-printed titanium cage for cervical vertebral defect healing in rabbits.

Three-dimensional (3D) printed titanium (Ti-6Al-4V alloy) cages are widely used for spinal fusion applications. However, the structural design and shape of the cages are a major determinant of the optimal clinical outcome. In this study, we constructed a newly designed 3D-printed helical-shaped titanium cage (HTC) with a flexible body, and compared its healing and fusion efficacy in cervical vertebral defects after corpectomy in rabbits to that of a 3D-printed traditional titanium cage (TTC). We performed radiological examinations 1 and 16 weeks after TTC and HTC implantation. We assessed bone ingrowth in TTC and HTC using micro-computed tomography (micro-CT) and histological staining of tissue sections at 16 weeks. The radiographic data showed that the HTC-implanted group had better restoration of vertebral height than the TTC group, indicating a lower risk of cage subsidence. The micro-CT and histological observations showed that HTC promoted bone regeneration and osseointegration more effectively than TTC. Histomorphometry further revealed significant new bone formation in the HTC group compared to the TTC group. These findings demonstrate that HTC has better healing and bone fusion effects than TTC in cervical vertebral defects in rabbits, indicating its potential clinical value.