Advances in Cervical Artificial Disc Replacement for Cervical Spondylosis

Anterior cervical decompression and fusion(ACDF)treatment for cervical spondylosis has been more than half a century,and achieved good clinical results.However,with the continuous extension of follow-up time,the fusion segment-associated postoperative complications emerged gradually.Reserved cervical stability and activity,the concept of non-fusion was born.As a non-fusion technique,cervical artificial disc replacement(CADR)developed rapidly.With the continuous development of artificial prosthesis materials and design concepts,and specification and proficiency of surgical procedures,CADR has achieved better short and mid-term clinical efficacy than ACDF.Compared with ACDF,the main advantages of CADR are that the postoperative recovery is quick,the activity and stability of cervical vertebra are maintained,the height of cervical intervertebral space is restored,and the stress of adjacent segments and the rate of surgical renovation are reduced.In clinical work,as an emerging technology,CADR requires spine surgeons to control the surgical indications,contraindications,and patients'conditions strictly.This article reviews the research progress of CADR in order to provide new ideas for clinical treatment of cervical spondylosis.

Application of a modified surgical position in anterior approach for total cervical artificial disc replacement

BACKGROUND Total cervical artificial disc replacement(TDR)has been considered a safe and effective alternative surgical treatment for cervical spondylosis and degenerative disc disease that have failed to improve with conservative methods.Positioning the surgical patient is a critical part of the procedure.Appropriate patient positioning is crucial not only for the safety of the patient but also for optimizing surgical exposure,ensuring adequate and safe anesthesia,and allowing the surgeon to operate comfortably during lengthy procedures.The surgical posture is the traditional position used in anterior cervical approach;in general,patients are in a supine position with a pad under their shoulders and a ring-shaped pillow under their head.AIM To investigate the clinical outcomes of the use of a modified surgical position versus the traditional surgical position in anterior approach for TDR.METHODS In the modified position group,the patients had a soft pillow under their neck,and their jaw and both shoulders were fixed with wide tape.The analyzed data included intraoperative blood loss,position setting time,total operation time,and perioperative blood pressure and heart rate.RESULTS Blood pressure and heart rate were not significantly different before and after body positioning in both groups(P>0.05).Compared with the traditional position group,the modified position group showed a statistically significantly longer position setting time(P<0.05).However,the total operation time and intraoperative blood loss were significantly reduced in the modified position group compared with the traditional position group(P<0.05).CONCLUSION The clinical outcomes indicated that total operation time and intraoperative blood loss were relatively lower in the modified position group than in the traditional position group,thus reducing the risks of surgery while increasing the position setting time.The modified surgical position is a safe and effective method to be used in anterior approach for TDR surgery.

The Artificial Disc Nucleus and Other Strategies for Replacement of the Nucleus Pulposus:Past,Present and Future Designs for an Emerging Surgical Solution

Nucleus Pulposus(NP)Replacement is a developing surgical methodology for the treatment of pathology related to degeneration of intervertebral discs(IVDs).This article provides necessary context regarding the patholo-gies treated with this technology,the biomechanical structure and function of the IVD,and the procedures this technology aims to replace.Primarily,it provides an overview and discussion of commercial and experimental preformed and in situ curing prosthesis designs reported in the scientific literature and summarizes the results of biomechanical and clinical studies evaluating their efficacy.Contextual and updated information on the most recent research into NP replacement with novel hydrogel and tissue engineering(TE)strategies is described.Replacement of the NP allows for potential improvement in the treatment of degenerative spinal pathologies through minimally invasive surgical techniques.

Recent Advances in Finite Element Applications in Artificial Lumbar Disc Replacement

As a new choice for the treatment of degenerative lumbar disease, artificial lumbar disc replacement has been widely used in clinical surgery. The finite element is a very effective method to predict and simulate the surgery effect. The purpose of this paper is to review the applications of finite element in artificial lumbar disc replacement, such as design of artificial lumbar disc prosthesis, risk and effect evaluation of artificial lumbar disc replacement, and assessment of operation methods. Lastly, we discuss the future development of finite element method applied in this field, including personalized design of the prosthesis, postoperative behavior guide, and artificial lumbar disc replacement combined with fusion surgery. In conclusion, as an invaluable complement to biomechanical experiments and clinical studies, the finite element method makes important contributions to our understanding of biomechanics of intervertebral disc, and plays an important role in the field of artificial lumbar disc replacement.

Potential Application of Entangled Porous Titanium Alloy Metal Rubber in Artificial Lumbar Disc Prostheses

Entangled Porous Titanium Alloy Metal Rubber(EPTA-MR)was used as a nucleus pulposus material in the design of non-fusion intervertebral disc prosthesis for the first time.A novel artificial lumbar intervertebral disc prosthesis was designed by reconstructing the lumbar model with reverse engineering technology,and the biomechanical behavior of the prosthesis was simulated under varied working conditions.The nucleus pulposus size was determined by the actual size of human prosthesis.EPTA-MR samples with different densities were prepared by medical titanium alloy wire experimental studies were conducted on static stiffness,damping energy consumption,and fatigue life.The results indicated that the static stiffness of EPTA-MR could reach approximately 1500 N mm and its loss factor remained higher than 0.2,and the variation range was relatively small,with excellent vibration damping capacity and bearing capacity.Among them,the overall performance of EPTA-MR with a density of 2.5 g em 3 was closer to that of the physiologic intervertebral disc.A macro experiment of five million fatigue vibration tests combined with microstructure observation exhibited a wear rate of only 0.9396 g-MC with no noticeable change in the internal micro-morphology.Therefore,the EPTA-MR has a broad application prospect as the nucleus pulposus material of artificial intervertebral disc prosthesis.