Objective To compare the clinical outcomes between conventional percutaneous vertebroplasty (PVP) and targeted PVP in the treatment of osteoporotic vertebral compression fractures (OVCFs).Methods A retrospective cohort study was designed to review 215 cases of single level OVCFs hospitalized between January 2014 and December 2015.According to the procedure techniques,the patients were assigned to targeted PVP group (89 cases) and conventional PVP group (126 cases) which was further divided into sufficient filled subgroup (110 cases) and insufficient filled subgroup (16 cases) on basis of cement distribution.Key techniques of targeted PVP included accurate needle insertion to fractured area and cement injection using a push rob with a side opening.Operating time,cement injection volume,rate and types of cement leakage,cement distribution in the fractured area and visual analogue score (VAS) of back pain were compared between the two groups.Results Operating time in targeted PVP group was longer than that in conventional PVP group (P ＜ 0.05).There were no significant differences in cement injection volume and rate and types of cement leakage between the two groups (P ＞ 0.05).None in targeted PVP group showed insufficient cement distribution in fractured area,while 16 cases (12.7％) in conventional PVP group (P ＜ 0.05).No significant differences in preoperative VAS of back pain existed among targeted PVP group,sufficient subgroup and insufficient subgroup (P ＞ 0.05).VAS of back pain was significantly decreased after PVP in three groups (P ＜ 0.05).Difference in postoperative VAS of back pain between targeted PVP group and sufficient filled subgroup was insignificant (P ＞0.05).However,postoperative VAS of back pain in insufficient filled subgroup was significantly increased compared with targeted PVP group and sufficient filled subgroup (P ＜ 0.05).Conclusion Targeted PVP provides sufficient cement to fill the fractured area and decreases incidence of unsatisfactory clinical outcome compared with traditional PVP,indicating a secure and effective new technique in the treatment of OVCFs.

BACKGROUND:The problem of intervertebral disc injury and degeneration has been studied in many ways.Many studies have shown that intervertebral disc injury and degeneration is driven by mechanical loading factors.However,the potential relationship between common phenotypes of intervertebral disc injury and degeneration and mechanical loading factors has been rarely summarized. OBJECTIVE:To summarize the types of common structural abnormalities exhibited by intervertebral disc injury and degeneration in the published literature,and sum up the potential links to the types of mechanical loading that lead to these structural abnormalities in in vitro and ex vivo experimental studies. METHODS:Using the terms"intervertebral disc failure,intervertebral disc injury,mechanical load,mechanical factor,load factor,biomechanics"as Chinese and English key words in PubMed,CNKI,and WanFang databases,articles related to intervertebral disc injury degeneration and mechanical load factors were retrieved.Literature screening was performed according to the inclusion and exclusion criteria,and 88 articles were finally included. RESULTS AND CONCLUSION:(1)Common structural abnormalities of intervertebral discs include decreased intervertebral disc height,disc bulge,osteophyte formation,annulus fibrosus tear,intervertebral disc herniation or disc prolapse,endplate damage,Schmorl nodes and intervertebral disc calcification.Intervertebral discs are susceptible to mechanical load types such as compression,bending,axial rotation,and compound loads.(2)The compressive load mainly causes the decrease of the proteoglycan content and the water-binding ability of the intervertebral disc,leading to the decrease or swelling of the intervertebral disc and further damage and degeneration of the intervertebral disc.In addition,the excessive compressive load causes greater damage to the endplate.(3)Bending load and axial rotation load damage the annulus fibrosus more than the endplate,and prolonged or repeated bending loads can cause tearing of the fibrous annulus and herniation or prolapse of the intervertebral disc,while pure axial rotation loads can induce less damage to the intervertebral disc and only cause the tear of the annulus fibrosus.(4)However,when different load types act in combination,it is more likely to result in high stress on the disc and a greater risk of disc injury.(5)Injury and degeneration of the intervertebral disc present progressive structural damage,and early prevention and protection are particularly important in clinical practice.Future tissue engineering research can start with early repair of the intervertebral disc.