Cell-based regenerative approaches have been suggested as primary or adjuvant procedures for the treatment of degenerated intervertebral disc (IVD) diseases. Our aim was to evaluate the regenerative and immunogenic properties of mildly and severely degenerated cervical nucleus pulposus (NP) cells with regard to cell isolation, proliferation and differentiation, as well as to cell surface markers and co-cultures with autologous or allogeneic peripheral blood mononuclear cells (PBMC) including changes in their immunogenic properties after 3-dimensional (3D)-culture. Tissue from the NP compartment of 10 patients with mild or severe grades of IVD degeneration was collected. Cells were isolated, expanded with and without basic fibroblast growth factor and cultured in 3D fibrin/poly (lactic-co-glycolic) acid transplants for 21 days. Real-time reverse-transcription polymerase chain reaction (RT-PCR) showed the expression of characteristic NP markers ACAN, COL1A1 and COL2A1 in 2D- and 3D-culture with degeneration- and culture-dependent differences. In a 5,6-carboxyfluorescein diacetate N-succinimidyl ester-based proliferation assay, NP cells in monolayer, regardless of their grade of degeneration, did not provoke a significant proliferation response in T cells, natural killer (NK) cells or B cells, not only with donor PBMC, but also with allogeneic PBMC. In conjunction with low inflammatory cytokine expression, analyzed by Cytometric Bead Array and fluorescence-activated cell sorting (FACS), a low immunogenicity can be assumed, facilitating possible therapeutic approaches. In 3D-culture, however, we found elevated immune cell proliferation levels, and there was a general trend to higher responses for NP cells from severely degenerated IVD tissue. This emphasizes the importance of considering the specific immunological alterations when including biomaterials in a therapeutic concept. The overall expression of Fas receptor, found on cultured NP cells, could have disadvantageous implications on their potential therapeutic applications because they could be the targets of cytotoxic T-cell activity acting by Fas ligand-induced apoptosis.

Cervical corpectomies are increasingly used to treat degenerative, metastatic, inflammatory and traumatic multisegmental diseases. The postoperative results are thought to correlate mainly with the number of resected vertebral bodies. Thus, the aim of the study was to analyse complications and early outcome of these procedures to document the implant-related complications in order to set up a prospective clinical trial. Forty-five patients, who were treated in our department from 2011 to 2014 and who were available for a minimum follow-up of 1 year, were consecutively included in this retrospective evaluation. The median age was 61 (±11) years with a female to male sex ratio of 19 to 26, respectively. In these patients, cervical corpectomies (one-, two- and three-level procedures) were performed. The average number of resected levels was 1.2 levels. The intraoperative loss of blood (LOB), the red cell transfusions (rcT), the length of operation (LOO) and the usage of drains were investigated and correlated with intra- and postoperative complications. The mean LOO was 244 min (±68) with a mean LOB of 511 ml (±531). The overall complication rate was 22.9% (10 patients). Six patients (13.3%) had implant-related complications due to loosening and toggling of the screws and/or cage subsidence. Two patients (4.4%) had a postoperative haematoma and another two patients (4.4%) suffered from neurological deterioration due to an ongoing and severe myelopathic syndrome. All these patients received revision surgery. The average time from the first to revision surgery was 90 days. Cervical corpectomies still remain procedures with a high complication rate mainly represented by implant-related failures. These implant-related complications range from screw/plate loosening or toggling to graft dislocation with subsidence and might be associated with constructs extended to the C7 vertebral body. In our study population, the rate of implant failure was comparable to the literature, but not obviously correlated with the number of vertebral bodies resected. This may be attributed to the different disease entities. Thus, our results support the use of circumferential approaches for selected instability scenarios (metastatic or inflammatory diseases, kyphosis, osteoporosis, etc.) of one- and two-level corpectomies.

BackgroundOsteolytic lesions of the anterior aspects of C1 (lateral mass) are difficult to address in a minimally invasive fashion and are often treated by craniocervical instrumentation.MethodsWe report the feasibility and technical method of transoral vertebroplasty of the lateral mass of the atlas using image guidance and describe the workflow of the procedure. To our knowledge, there has not yet been a technical description of a transoral vertebroplasty using image guidance.ResultsAdequate positioning of the pedicle access needle using image guidance for addressing the lateral mass of C1 through a transoral, permuceous access can be achieved.ConclusionsWith the assistance of image guidance, it is safe and feasible to access the lateral mass of the atlas. This constitutes a minimally invasive and fast alternative for introducing the bone needle to C1 rather than using a fluoroscopic device alone.