Vascular stents are an essential tool in cardiovascular interventional therapy, and their demand is growing with the increasing incidence of cardiovascular diseases. Compared with permanent stents, which are prone to in-stent restenosis, and drug-eluting stents, which may cause late stent thrombosis, biodegradable stents offer advantages. After providing early radial support to prevent elastic recoil, biodegradable stents gradually degrade, allowing the vessel to regain its natural physiological contractility and undergo positive remodeling. A review of the current mainstream biodegradable metal stents, magnesium-based, iron-based, and zinc-based alloys, shows promising findings in both preclinical and clinical research. Magnesium-based stents exhibit good operability and low thrombosis rates, but their limitations include rapid degradation, hydrogen evolution, and significant pH changes in the microenvironment. Iron-based stents demonstrate excellent mechanical strength, formability, biocompatibility, and hemocompatibility, but their slow corrosion rate hampers broader clinical application; accelerating degradation remains key. Zinc-based alloys have a moderate degradation rate but relatively low mechanical strength; enhancing stent strength by alloying with other elements is the main improvement direction for zinc-based stents.
Humans ; Absorbable Implants ; Stents ; Alloys/chemistry* ; Magnesium/chemistry* ; Biocompatible Materials/chemistry* ; Zinc/chemistry* ; Drug-Eluting Stents ; Iron/chemistry* ; Metals/chemistry*

BACKGROUND: Loss of sacral slope has been shown to be an important anatomic basis for low back pain. The effect of sacral slope changes after lumbar fusion on pain relief remains unclear.OBJECTIVE: To analyze the variations of sacral slope and clinical significance at the early stage after posterior lumbar interbody fusion at L4-5.METHODS: Sixty patients with herniation at disc levels L4-5 and spinal stenosis (n=38) or lumbar spondylolisthesis at L4 (n=22) undergoing posterior lumbar interbody fusion were enrolled. All patients were followed up for 12-24 months to compare the sacral slop at baseline and postoperatively. The clinical outcomes were evaluated by MacNab criteria, and its correlation with age, sex and sacral slop variations was analyzed.RESULTS AND CONCLUSION: At 12-24 months postoperatively, the sacral slope in the two groups was significantly improved than that at baseline (P < 0.05), but there was no significant difference in sacral slop between two groups (P > 0.05). The age, sex and sacral slop variations showed no significant effects on the early clinical outcomes (P > 0.05).These results suggest that posterior lumbar interbody fusion can markedly improve the sacral slope in patients with spinal stenosis and lumbar spondylolisthesis at early period. Furthermore, age, sex, and sacral slope variations all show no obvious effect on postoperative early functional recovery.