2023, Vol. 27 ›› Issue (27): 4408-4413

Risk and prevention of intervertebral implant subsidence after anterior cervical decompression and fusion

Peng Jiancheng1, Yao Xiaoling1, Ling Haiqian1, Lai Ying2, Li Jie1   

Abstract: BACKGROUND: Intervertebral implant subsidence is one of the common complications after anterior cervical decompression and fusion, and it is important to understand this complication.  
OBJECTIVE: To summarize the domestic and foreign articles on the subsidence of intervertebral implants after anterior cervical decompression and fusion in order to provide clinical guidance for spine surgeons.
METHODS: A computed-based online retrieval of CNKI, Wanfang and PubMed databases was conducted with Chinese and English keywords of “intervertebral implant, subsidence, anterior cervical decompression and fusion, cage, review, biomechanical analysis, three-dimensional finite element, three-dimensional printing technology, complications, biomaterials”.
RESULTS AND CONCLUSION: (1) Among the preoperative factors, osteoporosis, lower body mass index, higher T1 slope and inverted cervical spine angle were the risk factors for cage subsidence after anterior cervical approach. (2) C6/7 is the most common segment for the subsidence of the interbody cage after anterior cervical approach. The incidence of long segments is higher than that of short segments. Most articles believe that titanium plate-cage internal fixation system can effectively reduce the subsidence risk. (3) The width, diameter and height of the implant are related to the postoperative subsidence rate and the risk of subsidence increases when the implant is placed in the center of the endplate. (4) Rectangular, anatomical, 12-lobed, porous structure cage and bionic pit surface can effectively reduce the risk of subsidence when placed on the side of the cage. (5) Compared with titanium alloy cages, polyether ether ketone cages have lower subsidence risk. Degradable materials and composite materials have been studied more in recent years, but their safety and effectiveness still need to be further proved. (6) Excessive curettage of the endplate, excessive distraction of the intervertebral body, prolonged distraction of the cervical retractor, poor screw placement, and poor implant placement angle are the risk factors of postoperative intervertebral implant subsidence; premature cervical collar removal after surgery increases the risk of subsidence. (7) Biomechanical research, materials research, 3D printing technology, and long-term follow-up are effective ways to study the subsidence of intervertebral implants after anterior cervical decompression and fusion in the future.

Key words: intervertebral implant, subsidence, anterior cervical decompression and fusion, cage, review