ObjectiveTo summarize the research progress on spontaneous facet fusion (SFF) after lumbar spine surgery, and provide reference for further research on SFF. Methods The definition, development, clinical significance, and related influence factors of SFF were throughout reviewed by referring to relevant domestic and foreign literature in recent years. Results SFF is a phenomenon of joint space disappearance and fusion of upper and lower articular processes, which starts in a ring shape from the outermost edges to the central regions. Currently reported SFF occurred after posterior lumbar pedicle screw fixation. SFF may increase the stability of surgical segments and relieve clinical symptoms of patients. SFF is closely related to the method of lumbar internal fixation, facet osteoarthritis, interbody fusion, age, body mass index, type B fracture (according to AO classification), and the operative segment. Conclusion Most reported SFF occur after posterior lumbar pedicle screw fixation, which can increase lumbar stability, but the mechanism and influencing factors remain to be further clarified.
Objective To summarize the effect of cage height on outcomes of lumbar interbody fusion surgery and the importance of the cage height selection. Methods The related literature was widely reviewed to summarize the research progress on the complications caused by inappropriate height of the cage and the methods of selecting cage height. Results Inappropriate height of the cage can lead to endplate injury, cage subsidence, internal fixation failure, adjacent segmental degeneration, over-distraction related pain, insufficient indirect decompression, instability of operation segment, poor interbody fusion, poor sequence of spine, and cage displacement. At present, the selection of the cage height is based on the results of the intraoperative model test, which is reliable but high requirements for surgical experience and hard to standardize. ConclusionThe inappropriate height of the cage may have an adverse impact on the postoperative outcome of patients. It is important to develop a selection standard of the cage height by screening the related influential factors.
ObjectiveTo summarize the advances in research on Cage subsidence following lumbar interbody fusion, and provide reference for its prevention.MethodsThe definition, development, clinical significance, and related risk factors of Cage subsidence following lumbar interbody fusion were throughout reviewed by referring to relevant domestic and doreign literature in recent years.ResultsAt present, there is no consensus on the definition of Cage subsidence, and mostly accepted as the disk height reduction greater than 2 mm. Cage subsidence mainly occurs in the early postoperative stage, which weakens the radiological surgical outcome, and may further damage the effectiveness or even lead to surgical failure. Cage subsidence is closely related to the Cage size and its placement location, intraoperative endplate preparation, morphological matching of disk space to Cage, bone mineral density, body mass index, and so on.ConclusionThe appropriate size and shape of the Cage usage, the posterolateral Cage placed, the gentle endplate operation to prevent injury, the active perioperative anti-osteoporosis treatment, and the education of patients to control body weight may help to prevent Cage subsidence and ensure good surgical results.