Zenghui Zhao

A hollow cylindrical nano-hydroxyapatite/polyamide composite strut for cervical reconstruction after cervical corpectomy☆

This retrospective study included 35 patients who had a nano-hydroxyapatite/polyamide (n-HA/PA) composite strut implanted for cervical reconstruction and fusion after corpectomy from 2006 to 2008. The average follow-up period was 38.5 months (range: 24-48 months). The Japanese Orthopedic Association score and visual analog pain scale score were significantly improved and maintained to the last follow-up. The cervical curvature and the height of fused segments were also corrected significantly and retained to the last follow-up. A total of 94.3% of patients had achieved radiographic bony fusion at the postoperative 24-month follow-up. One patient presented with subsidence of the n-HA/PA composite strut and dislodgement of the screws, but the patient had no discomfort and no additional surgery was needed. We conclude that the n-HA/PA composite strut is scientifically and technically sound for cervical reconstruction and interbody fusion after corpectomy with anterior plate fixation.

Evaluation of Anterior Cervical Reconstruction with Titanium Mesh Cages versus Nano-Hydroxyapatite/Polyamide66 Cages after 1- or 2-Level Corpectomy for Multilevel Cervical Spondylotic Myelopathy: A Retrospective Study of 117 Patients

Objective To retrospectively compare the efficacy of the titanium mesh cage (TMC) and the nano-hydroxyapatite/polyamide66 cage (n-HA/PA66 cage) for 1- or 2-level anterior cervical corpectomy and fusion (ACCF) to treat multilevel cervical spondylotic myelopathy (MCSM). Methods A total of 117 consecutive patients with MCSM who underwent 1- or 2-level ACCF using a TMC or an n-HA/PA66 cage were studied retrospectively at a mean follow-up of 45.28±12.83 months. The patients were divided into four groups according to the level of corpectomy (1- or 2-level corpectomy) and cage type used (TMC or n-HA/PA66 cage). Clinical and radiological parameters were used to evaluate outcomes. Results At the one-year follow-up, the fusion rate in the n-HA/PA66 group was higher, albeit non-significantly, than that in the TMC group for both 1- and 2-level ACCF, but the fusion rates of the procedures were almost equal at the final follow-up. The incidence of cage subsidence at the final follow-up was significantly higher in the TMC group than in the n-HA/PA66 group for the 1-level ACCF (24% vs. 4%, p = 0.01), and the difference was greater for the 2-level ACCF between the TMC group and the n-HA/PA66 group (38% vs. 5%, p = 0.01). Meanwhile, a much greater loss of fused height was observed in the TMC group compared with the n-HA/PA66 group for both the 1- and 2-level ACCF. All four groups demonstrated increases in C2-C7 Cobb angle and JOA scores and decreases in VAS at the final follow-up compared with preoperative values. Conclusion The lower incidence of cage subsidence, better maintenance of the height of the fused segment and similar excellent bony fusion indicate that the n-HA/PA66 cage may be a superior alternative to the TMC for cervical reconstruction after cervical corpectomy, in particular for 2-level ACCF.

Tranexamic acid reduces perioperative blood loss of posterior lumbar surgery for stenosis or spondylolisthesis: A randomized trial

Background: A prospective, randomized, double-blind, placebo-controlled study was performed. The routine usage of TA in spinal surgery is controversial. Only a few studies have focused on patients undergoing posterior lumbar surgery for stenosis or spondylolisthesis, although a large clinical cohort exists in the population. This study aimed to evaluate the effect and safety of TA in reducing perioperative blood loss in posterior lumbar surgery for stenosis or spondylolisthesis. Methods: 100 eligible patients out of 126 were randomized to receive either a bolus dose of 30 mg/kg TA i.v, a maintenance dosage of 2 mg/kg/h TA, or an equivalent volume of normal saline. The pedicle screw system was used for fixing in all the patients, followed by decompression and posterior lumbar interbody fusion. The primary outcomes were intraoperative estimated blood loss and total blood loss. The secondary outcomes were receiving packed red blood cells and postoperative hemoglobin and hematocrit levels. Results: In total, 4 patients were excluded from the analyses, 50 patients were in the TA group, and 46 in the placebo group. The demographic and baseline data between the groups were not statistically different. The intraoperative estimated blood loss and the total blood loss were 33% and 41% lower in the TA group than the placebo group, respectively. The blood transfusion rate did not vary significantly (P = 0.191). Except a patient with a dural tear in the placebo group, no other complications were observed. Conclusion: TA significantly reduced the perioperative blood loss in patients undergoing posterior lumbar surgery for stenosis or spondylolisthesis.

Functionalized d-form self-assembling peptide hydrogels for bone regeneration.

Bone defects are very common in orthopedics, and there is great need to develop suitable bone grafts for transplantation in vivo. However, current bone grafts still encounter some limitations, including limited availability, immune rejection, poor osteoinduction and osteoconduction, poor biocompatibility and degradation properties, etc. Self-assembling peptide nanofiber scaffolds have emerged as an important substrate for cell culture and bone regeneration. We report on the structural features (eg, Congo red staining, circular dichroism spectroscopy, transmission electron microscopy, and rheometry assays) and osteogenic ability of d-RADA16-RGD peptide hydrogels (with or without basic fibroblast growth factor) due to the better stability of peptide bonds formed by these peptides compared with those formed by l-form peptides, and use them to fill the femoral condyle defect of Sprague Dawley rat model. The bone morphology change, two-dimensional reconstructions using microcomputed tomography, quantification of the microcomputed tomography analyses as well as histological analyses have demonstrated that RGD-modified d-form peptide scaffolds are able to enhance extensive bone regeneration.

Long-term results of anterior cervical corpectomy and fusion with nano-hydroxyapatite/polyamide 66 strut for cervical spondylotic myelopathy

To assess the long-term clinical and radiographic outcomes of anterior cervical corpectomy and fusion (ACCF) with a neotype nano-hydroxyapatite/polyamide 66 (n-HA/PA66) strut in the treatment of cervical spondylotic myelopathy (CSM). Fifty patients with CSM who underwent 1- or 2-level ACCF with n-HA/PA66 struts were retrospectively investigated. With a mean follow-up of 79.6 months, the overall mean JOA score, VAS and cervical alignment were improved significantly. At last follow-up, the fusion rate was 98%, and the subsidence rate of the n-HA/PA66 strut was 8%. The “radiolucent gap” at the interface between the n-HA/PA66 strut and the vertebra was further noted to evaluate the osteoconductivity and osseointegration of the strut, and the incidence of it was 62% at the last follow-up. Three patients suffered symptomatic adjacent segment degeneration (ASD). No significant difference was detected in the outcomes between 1- and 2-level corpectomy at follow-ups. In conclusion, the satisfactory outcomes in this study indicated that the n-HA/PA66 strut was an effective graft for cervical reconstruction. Moreover, the osteoconductivity and osseointegration of the strut is still need to be optimized for future clinical application owing to the notably presence of “radiolucent gap” in present study.

Single-Stage Posterior Instrumentation and Unilateral Transpedicular Debridement for the Treatment of Thoracolumbar Tuberculosis: Three Years of Follow-Up

OBJECTIVE The present study compared the efficacy and safety of single-stage posterior instrumentation and unilateral transpedicular debridement with the traditional posterior operation for the treatment of thoracolumbar tuberculosis. METHODS Of the 97 included patients, 53 had undergone posterior unilateral transpedicular debridement and pedicle screw fixation (group A) and 44 had undergone the traditional posterior operation (group B). We compared the outcomes, including correction of kyphosis (Cobb angle), bone fusion rate, visual analog scale score, Frankel classification, and short-form 12-item health survey between the 2 groups. RESULTS All patients obtained intervertebral bone fusion. The mean interval to bone graft fusion was 4.1 months (range, 3-8 months). The patients in the 2 groups showed significant improvement in kyphosis correction, short-form 12-item health survey score, and nerve function. In addition, single-stage posterior instrumentation and unilateral transpedicular debridement resulted in comparable clinical outcomes for the treatment of thoracolumbar tuberculosis. However, the patients experienced less trauma, greater spinal stability, and better functional recovery compared with the traditional posterior operation group. CONCLUSIONS Our results suggest that single-stage posterior instrumentation and unilateral transpedicular debridement can be considered an effective and safe therapy for spinal tuberculosis with single-level and/or bi-level segments.

Establishment and characterization of human osteosarcoma cells resistant to pyropheophorbide-α methyl ester-mediated photodynamic therapy

The present study was performed to establish and characterize new human osteosarcoma cell lines resistant to pyropheophorbide-α methyl ester-mediated photodynamic therapy (MPPa-PDT). MPPa-PDT-resistant cells are isolated from the human osteosarcoma MG63 and HOS cell lines and two resistant populations were finally acquired, including MG63/PDT and HOS/PDT. Cell Counting Kit-8 (CCK-8) assay was used to determine the MPPa-PDT, cisplatin (CDDP) resistance and proliferation of MG63, MG63/PDT, HOS and HOS/PDT cells. The intracellular ROS were analyzed using DCFH-DA staining. The colony formation, invasion and migration of parental and resistant cells were compared. FCM was employed to examine the cell cycle distribution, the apoptosis rate and the proportion of CD133+ cells. The fluorescence intensity of intracellular MPPa was observed by fluorescence microscopy and quantified using microplate reader. The protein levels were assessed by western blotting (WB). Compared with two parental cells, MG63/PDT and HOS/PDT were 1.67- and 1.61-fold resistant to MPPa-PDT, respectively, and also exhibited the resistance to CDDP. FCM assays confirmed that both MG63/PDT and HOS/PDT cells treated with MPPa-PDT displayed a significantly lower apoptosis rate in comparison with their corresponding parental cells. The expression of apoptosis-related proteins (i.e. cleaved-caspase 3 and cleaved-PARP), intracellular ROS and the antioxidant proteins (HO-1 and SOD1) in MG63/PDT and HOS/PDT cells was also lower than that in parental cells. Both MG63/PDT and HOS/PDT cells exhibited changes in proliferation, photosensitizer absorption, colony formation, invasion, migration and the cell cycle distribution as compared to MG63 and HOS cells, respectively. Compared to MG63 and HOS cells, both resistant cell lines had a higher expression of CD133, survivin, Bcl-xL, Bcl-2, MRP1, MDR1 and ABCG2, but a lower expression of Bax. The present study successfully established two resistant human osteosarcoma cell lines which are valuable to explore the resistance-related mechanisms and the approaches to overcome resistance.