Study design A retrospective review of prospectively collected data in an academic institution. Objective To evaluate the safety and efficacy of a new type of titanium mesh cage (TMC) in single-level, anterior cervical corpectomy and fusion (ACCF). Methods Fifty-eight patients consecutive with cervical spondylotic myelopathy (CSM) from cervical degenerative spondylosis and isolated ossification of the posterior longitudinal ligament were treated with a single-level ACCF using either a new type of TMC (28 patients, group A) or the traditional TMC (30 patients, group B). We evaluated the patients for TMC subsidence, cervical lordosis (C2-C7 Cobb and Cobb of fused segments) and fusion status for a minimum of 30 months postoperatively based on spine radiographs. In addition, neurologic outcomes were evaluated using the Japanese Orthopedic Association (JOA) scores. Neck pain was evaluated using a 10-point visual analog scale (VAS). Results The loss of height of the fused segments was less for group A than for group B (0.8 ± 0.3 vs. 2.8 ± 0.4 mm) (p \ 0.01); also, there was a lower rate of severe subsidence (C3 mm) in group A (4 %, 1/28) than in group B (17 %, 5/30) (p \ 0.01). There were no differences in the C2-C7 Cobb and Cobb of fused segments between the groups preoperatively or at final follow-up (p [ 0.05), but the Cobb of fused segments immediately postoperative were significantly less for group B than for group A (p \ 0.01). All patients, however, had successful fusion (100 %, each). Both groups had marked improvement in the JOA score after operation (p \ 0.01), with no significant differences in the JOA recovery ratio (p [ 0.05). The postoperative VAS neck pain scores for group A were significantly less than that for group B (p \ 0.05); severe subsidence was correlated with neck pain. Conclusions The new type of TMC provides comparable clinical results and fusion rates with the traditional TMC for patients undergoing single-level corpectomy. The new design TMC decreases postoperative subsidence (compared to the traditional TMC); the unique design of the new type of TMC matches the vertebral endplate morphology which appears to decrease the severity of subsidencerelated neck pain in follow-up.

The primary clinical and radiographic efficacies of Zero-P used in ACDF were satisfactory. The device could improve and maintain the cervical lordosis and disk height. The incidence of postoperative dysphagia was low. More patients and longer follow-up are demanded to confirm the results we have obtained in this study.

Background Intervertebral disc degeneration (IVDD) is the breakdown of the discs supporting the vertebrae. It is one of the most frequent causes of back pain worldwide. Currently, the clinical interventions for IVDD are mainly focused on symptom releases. Thus, new therapeutic options are needed. Methods Nucleus pulposus (NP) samples were obtained from 20 patients experiencing IVDD and 10 healthy volunteers compared for mRNA N6-methyladenosine (m6A) mRNA modification as well as methyltransferase (METT) like METTL3, METTL14, and Wilms’ tumor 1-associated protein mRNA and protein abundance following exosomes exposure from mesenchymal stem cells. In addition, microRNA expressions were also compared. The correlation between the NLR family pyrin domain containing 3 (NLRP3) and METTL14 was measured by luciferase reporter assay. Cytokines were evaluated using an enzyme-linked immunosorbent assay. METTL14, NLRP3, and insulin-like growth factor 2 mRNA-binding protein 2 mRNAs were measured via a quantitative reverse transcription-polymerase chain reaction. Protein was assayed using western blots. Cell death was assessed by propidium iodide staining, lactate dehydrogenase release, gasdermin-N domain abundance, and caspase-1 activation. Results The human umbilical cord mesenchymal stem cell (hucMSC) exosomes were found to effectively improve the viability of NP cells and protect them from pyroptosis through targeting METTL14, with a methyltransferase catalyzing m6A modification. METTL14 was highly present in NP cells from IVDD patients, which stabilize NLRP3 mRNA in an IGFBP2-dependent manner. The elevated NLRP3 levels result in the increase of interleukin 1β (IL-1β) and IL-18 levels and trigger pyroptotic NP cell death. Such pathogenic axis could be blocked by hucMSC exosomes, which directly degrade METTL14 through exosomal miR-26a-5p. Conclusions The results of the current study revealed the beneficial effects of hucMSC exosomes on NP cells and determined a potential mechanism inducing IVDD.