Skip-level anterior cervical discectomy and fusion with self-locking stand-alone PEEK cages for the treatment of 2 noncontiguous levels of cervical spondylosis.

STUDY DESIGN: Retrospectively study. OBJECTIVES: To evaluate clinical and radiologic outcomes of skip-level anterior cervical discectomy and fusion (ACDF) with self-locking stand-alone polyetheretherketone (PEEK) cages for the treatment of 2 noncontiguous levels of cervical disk degenerative disease (CDDD). SUMMARY OF BACKGROUND DATA: The use of stand-alone PEEK cages in ACDF has been proved to be safe and effective to treat CDDD. For 2 noncontiguous levels of CDDD, skip-level ACDF with self-locking stand-alone PEEK cages, which fuses only the involved levels without anterior plates, may be the optimal treatment choice. METHODS: Sixteen consecutive patients with 2 noncontiguous levels of CDDD underwent skip-level ACDF with self-locking stand-alone PEEK cages. Clinical outcomes were evaluated using Japanese Orthopaedic Association scores and Odom criteria. Fusion rate and time, cages subsidence, spinal curvature, intervertebral height at the operated level, and adjacent disk degeneration were assessed. RESULTS: Patients were followed up for average 43.6 months (range, 24-78 mo). The mean operative time was 113 minutes (range, 98-134 min) with an average blood loss of 62 mL (range, 47-76 mL). The Japanese Orthopaedic Association score, degree of spinal curvature, and intervertebral height were significantly increased at the final follow-up examination compared with preoperatively (P<0.05). Fifteen patients (93.8%) achieved solid fusion in an average time of 5.1 months. Three cages (9.38%) in 2 patients subsided. Radiologic evidence of adjacent segment degeneration was observed in 3 segments (6.25%; 2 infra-adjacent segments and 1 intermediate segment). No case had neurological deterioration postoperatively. No implant failure or migration was observed during follow-up. CONCLUSIONS: Treatment of 2 noncontiguous levels of CDDD with skip-level ACDF with self-locking stand-alone cages achieved good clinical and radiologic outcomes including a high fusion rate, low complication rate, and excellent maintenance of spinal curvature and intervertebral height.

Comparison of stand-alone polyetheretherketone cages and iliac crest autografts for the treatment of cervical degenerative disc diseases.

BACKGROUND: Anterior cervical decompression and fusion (ACDF) is a widely accepted surgical procedure for the treatment of cervical degenerative disc diseases. This retrospective study was designed to analyze and compare the efficacy and outcomes of anterior cervical fusion using stand-alone polyetheretherketone (PEEK) cages and autogenous iliac crest grafts with the anterior cervical plating system. METHODS: A total of 72 consecutive patients suffering from cervical degenerative disc diseases treated with ACDF from June 2005 to Dec 2008 were enrolled in the study. Patients in group A (40 patients, 64 segments) had anterior interbody fusion with stand-alone PEEK cages and patients in group B (32 patients, 51 segments) with autogenous iliac crest graft combined with anterior plate fixation. The operative time and intraoperative blood loss were recorded. Clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) scoring system; cervical lordosis, intervertebral height, and cervical fusion status were assessed on X-ray and computed tomography. FINDINGS: The mean follow-up period was 17.3 months in the stand-alone cage group and 23.2 months in the autologous iliac crest graft group. The operative time and intraoperative blood loss in group A were much less than those in group B (p < 0.05). All the patients in both groups got complete interbody fusion. Postoperative JOA scores in both group A and group B were more than the preoperative ones with significant differences, and the improvement rate of JOA scores had no statistical differences between group A and group B. Postoperative cervical physiological curvature and intervertebral height in both groups were better than the preoperative ones with statistical significances. CONCLUSIONS: The stand-alone PEEK cage is a good substitute for fusion in patients with cervical disc disease; it can effectively restore the cervical physiological curvature and the intervertebral height, facilitate radiological follow-up, cause few complications, and leads to satisfactory outcomes.

Thermosensitive hydrogels loaded with human-induced pluripotent stem cells overexpressing growth differentiation factor-5 ameliorate intervertebral disc degeneration in rats.

To evaluate the effects of thermosensitive hydrogels loaded with human-induced pluripotent stem cells transfected with the growth differentiation factor-5 (GDF5-hiPSCs) on rat intervertebral disc regeneration. GDF5-hiPSCs were cocultured with rat nucleus pulposus (NP) cells in vitro. Real-time PCR and western blot were used to determine the differentiation of hiPSCs. Rat caudal intervertebral discs were punctured using a needle under X-ray, and groups of coccygeal (Co) discs were subject to various treatments: Puncture group (Co6/7, punctured without treatment); Hydrogel group (Co7/8, 2 µl of hydrogel injected without cells); GDF5-hiPSCs + Hydrogel group (Co8/9, 2 µl of GDF5-hiPSCs-loaded hydrogel injected); and Normal control (Co5/6). X-ray, MRI, and histological evaluations were performed at 1, 2, and 3 months after cell transplantation and relative changes in the disc height index (DHI%) and voxel count were calculated and compared. GDF5-hiPSCs were successfully differentiated to a chondrogenic linage after cocultured with rat NP cells. In terms of X-ray, MRI, and HE staining scores, the GDF5-hiPSCs + Hydrogel group was significantly superior to the Puncture and Hydrogel groups (p < .05). Compared with the Normal group, the MRI-based voxel count of the GDF5-hiPSCs + Hydrogel group was significantly lower at 1, 2, and 3 months after cell transplantation (p < .05). However, there were no significant differences in histological scores at 1 and 2 months after cell transplantation compared with the Normal group (p > .05). In conclusion, thermosensitive hydrogel-encapsulated hiPSCs overexpressing the GDF5 gene ameliorated intervertebral disc degeneration.

Bioabsorbable self-retaining PLA/nano-sized ß-TCP cervical spine interbody fusion cage in goat models: an in vivo study.

STUDY DESIGN: This is an experimental animal study. OBJECTIVE: The objective of this study was to compare an anterior cervical discectomy and interbody fusion of a novel polylactide/nano-sized ß-tricalcium phosphate (PLA/nß-TCP) bioabsorbable self-retaining cervical fusion cage (BCFC) with an autologous bone graft and polyetheretherketone (PEEK) cages. BACKGROUND: Although PLA cervical cages have potential advantages compared with traditional materials, they are not currently routinely used in spine surgery because of undesirable effects such as the lack of osteoconductivity and osteolysis around the implant. This study involved the manufacturing of a bioabsorbable cage from PLA/nß-TCP that was then used as a device for anterior cervical discectomy and fusion (ACDF) on a goat cervical spine fusion model. MATERIALS AND METHODS: Eighteen goats underwent C3/C4 discectomy and were randomly divided into three groups based on the following methods: Group A (n=6), an autologous bone graft; Group B (n=6), PEEK cage filled with an autologous graft; and Group C (n=6), BCFC filled with an autologous iliac bone. Radiography was performed preoperatively and postoperatively and at 1, 4, 8, and 12 weeks after the operation. Disc space height (DSH) was measured at the same time. After 12 weeks, the fused segments were harvested and evaluated with functional radiographic views, biomechanical testing, and histological analyses. RESULTS: Over a 12-week period, the BCFC and PEEK cage groups exhibited significantly higher DSH values than the bone graft group. Additionally, the BCFC group yielded a significantly lower range of motion in axial rotation than both the autologous bone graft and PEEK cage groups. A histologic evaluation revealed an increased intervertebral bone volume/total volume ratio and better interbody fusion in the BCFC group than in the other groups. CONCLUSION: The BCFC device exhibited better results than the autologous bone graft and PEEK cages in single-level ACDF models in vivo. This device may be a potential alternative to the current PEEK cages.

Biomechanical stability of a bioabsorbable self-retaining polylactic acid/nano-sized ß-tricalcium phosphate cervical spine interbody fusion device in single-level anterior cervical discectomy and fusion sheep models.

PURPOSE: The aim of this study was to investigate the biomechanical stability provided by a novel, polylactic acid/nano-sized, ß-tricalcium phosphate, bioabsorbable, self-retaining cervical fusion cage (BCFC). METHODS: Quasistatic nonconstraining torques (maximum 1.5 NM) induced flexion, extension, lateral bending (±1.5 NM), and axial rotation (±1.5 NM) on 32 sheep cervical spines (C2-C5). The motion segment C3-C4 was first tested intact; the following groups were tested after complete discectomy: autologous tricortical iliac crest bone graft, Medtronic-Wego polyetheretherketone (PEEK) cage, Solis PEEK cage, and BCFC. The autologous bone graft group was tested with an anterior plate. The mean range of motion (ROM) was calculated from the load-displacement curves. RESULTS: BCFC significantly decreased ROM in lateral bending and axial rotation compared to other implants, and no significant difference in ROM between two types of PEEK cages and BCFC could be observed in flexion and extension. Anterior cervical plate (ACP) significantly decreased ROM in flexion and extension, but no significant difference in ROM between BCFC and bone graft plus ACP could be determined in lateral bending and axial rotation. CONCLUSION: The BCFC device showed better stability to autologous tricortical iliac crest bone graft and PEEK cages in single-level anterior cervical discectomy and fusion models and thus may be a potential alternative to the current PEEK cages.

Degradation and osteogenic potential of a novel poly(lactic acid)/nano-sized ß-tricalcium phosphate scaffold.

The purpose of this study was to investigate the influence of nano-sized ß-tricalcium phosphate (ß-TCP) on the biological performance of poly (lactic acid) (PLA) composite scaffolds by using in vitro degradation and an in vivo model of heterotopic bone formation. Nano-sized ß-TCP (nß-TCP) was prepared with a wet grinding method from micro-sized ß-TCP (mß-TCP), and composite scaffolds containing 0, 10, 30, or 50 wt% nß-TCP or 30 wt% mß-TCP were generated using a freeze-drying method. Degradation was assessed by monitoring changes in microstructure, pH, weight, and compressive strength over a 26-week period of hydrolysis. Composite scaffolds were processed into blocks, and implanted into muscular pockets of rabbits after loading with recombinant human bone morphogenetic protein-2 (rhBMP-2). New bone formation was evaluated based on histological and immunohistochemical analysis 2, 4, and 8 weeks after implantation. The in vitro results indicated that the buffering effect of nß-TCP was stronger than mß-TCP, which was positively correlated with the content of nß-TCP. The in vivo findings demonstrated that nß-TCP enhanced the osteoconductivity of the scaffolds. Although composite scaffolds containing 30% nß-TCP exhibited similar osteoconductivity to 50% nß-TCP, they had better mechanical properties than the 50% nß-TCP scaffolds. This study supports the potential application of a composite scaffold containing 30% nß-TCP as a promising scaffold for bone regeneration.

Three-level anterior cervical discectomy and fusion with self-locking stand-alone polyetheretherketone cages.

Anterior cervical plating is regarded as standard practice after multilevel anterior cervical discectomy and fusion. However, plate implantation in the anterior cervical spine poses a substantial risk of hardware-related complications. We retrospectively analyzed the efficacy and outcomes of 15 consecutive patients treated with a 3-level anterior cervical fusion using self-locking stand-alone polyetheretherketone (PEEK) cages. Patients were evaluated preoperatively and postoperatively using the Japanese Orthopedic Association (JOA) scale scores and radiographs. Clinical results were assessed using Odom's criteria. The mean JOA score (± standard deviation) improved significantly from 7.3 ± 1.5 points to 14.1 ± 1.3 points (p < 0.05) at the final follow-up. The outcomes were excellent for four patients (26.7%), good for nine patients (60%) and fair for two patients (13.3%). None of the patients experienced a poor clinical outcome. Thirteen patients achieved a solid fusion, after an average time of 5.7 months. The radiographic fusion rate of this procedure was 93.3%. Of 45 cages inserted in total, only four (8.89%) cages, in three patients, were found to have subsided. The degree of spinal curvature before surgery differed significantly from that immediately after surgery, and from that at the final follow-up examination (p < 0.05). Self-locking stand-alone PEEK cages packed with excised local osteophytes and calcium sulfate are safe and effective. This procedure can effectively restore cervical lordosis, obviate the complications related to graft harvest and screw-plate fixation, and lead to satisfactory outcomes.