Wen-Fei Ni

Percutaneous pedicle screw fixation for neurologic intact thoracolumbar burst fractures.

Study Design Prospective consecutive series. Objective To evaluate the efficacy and safety of percutaneous pedicle screw fixation (PPSF) for thoracolumbar AO type A3 fractures with a specially designed surgical instrument system. Summary of Background Data Minimally invasive surgery including PPSF is becoming increasingly widespread in the spine surgery. The technique of PPSF was mostly used as supplemental fixation combined with minimally invasive posterior or anterior lumbar interbody fusion in management of lumbar degenerative disorders. There are fewer studies available in literature regarding PPSF without additional kyphoplasty or vertebroplasty for management of thoracolumbar burst fractures. Methods Thirty-six adult patients, who had single thoracolumbar AO type A3 fractures and the load-sharing score of 6 or less, underwent application of percutaneous short-segment pedicle screw fixation. Radiologic parameters including kyphotic angle and vertebral height loss were assessed before and after surgery, and functional outcome was evaluated by Prolo questionnaire. Results All patients were successfully managed with percutaneous minimal invasive procedures. The average operative time was 78 minutes (range 62 to 117 min). The average intraoperative blood loss was 75 mL (range 50 to 220 mL). After a mean follow-up of 48.5 months (range 32 to 63 mo), 31 of 36 (86.1%) patients had a satisfactory result (19 excellent and 12 good) and 5 of them fair. Conclusions Our clinical results suggest that PPSF can be an alternative for management of thoracolumbar AO type A3 fractures that have no neurologic deficits. With a specially designed percutaneous instrument and pedicle screw system, the procedure has been proved as relatively safe and a minimally invasive approach for the management of thoracolumbar burst fracture without neurologic deficit.

The Relationship Between Vitamin A and Risk of Fracture: Meta-Analysis of Prospective Studies

Osteoporotic fracture is a significant cause of morbidity and mortality and is a challenging global health problem. Previous reports of the relation between vitamin A intake or blood retinol and risk of fracture were inconsistent. We searched Medline and Embase to assess the effects of vitamin A (or retinol or beta‐carotene but not vitamin A metabolites) on risk of hip and total fracture. Only prospective studies were included. We pooled data with a random effects meta‐analysis with adjusted relative risk (adj.RR) and 95% confidence interval (CI). We used Q statistic and I2 statistic to assess heterogeneity and Eggers test to assess publication bias. Eight vitamin A (or retinol or beta‐carotene) intake studies (283,930 participants) and four blood retinol level prospective studies (8725 participants) were included. High intake of vitamin A and retinol were shown to increase risk of hip fracture (adj.RR [95% CI] = 1.29 [1.07, 1.57] and 1.40 [1.03, 1.91], respectively), whereas beta‐carotene intake was not found to increase the risk of hip fracture (adj.RR [95% CI] = 0.82 [0.59, 1.14]). Both high or low level of blood retinol was shown to increase the risk of hip fracture (adj.RR [95% CI] = 1.87 [1.31, 2.65] and 1.56 [1.09, 2.22], respectively). The risk of total fracture does not differ significantly by level of vitamin A (or retinol) intake or by blood retinol level. Dose‐response meta‐analysis shows a U‐shaped relationship between serum retinol level and hip fracture risk. Our meta‐analysis suggests that blood retinol level is a double‐edged sword for risk of hip fracture. To avoid the risk of hip fracture caused by too low or too high a level of retinol concentration, we suggest that intake of beta‐carotene (a provitamin A), which should be converted to retinol in blood, may be better than intake of retinol from meat, which is directly absorbed into blood after intake.

In vitro neural differentiation of bone marrow stromal cells induced by cocultured olfactory ensheathing cells

Bone marrow stromal cells (BMSCs) could be induced to differentiate into neural cells under certain conditions, nevertheless, optimal protocols that could be reproducible and reliable in generating transplantable BMSCs in vitro are still not available. We studied for the first time the neural differentiation of BMSCs induced by coculturing with olfactory ensheathing cells (OECs). BMSCs and OECs were isolated from bone marrow and nasal olfactory lamina propria of adult SD rats respectively, then brought to coculture with transwell culture dishes. At various time points (0h, 6h, 12h, 24h, 72h, 1 week and 2 weeks post-coculture), BMSCs were morphologically observed and processed for immunofluorescence and reverse transcription-polymerase chain reaction (RT-PCR). The number of cells assuming neural morphology dramatically increased at 1- and 2-week-post-coculture, so as the number of immunoreactive cells labeled by neural markers NSE, beta-III-tubulin, MAP2, GFAP and p75(NTR). Our findings demonstrate that BMSCs can efficiently differentiate into neural cells when coculturing with OECs, and the present protocol provides an alternative neurogenesis pathway for generating sufficient numbers of neural cells from BMSCs.

Microendoscopic anterior approach for irreducible atlantoaxial dislocation: surgical techniques and preliminary results.

Study Design Surgical techniques and preliminary results. Objective To describe and evaluate the safety and efficacy of a new minimal invasive technique for the irreducible atlantoaxial dislocation (IADD). Summary of Background Data Endoscope has been widely used in minimal invasive spinal surgery. However, there are no clinical reports regarding anterior approach for IADD in the literature. Methods Ten consecutive patients with IADD were treated by anterior release with microendoscopic aide and subsequently reduction, anterior transarticular screw fixation and morselized autologous bone grafts. There were 3 cases of odontiod dysplasia, 4, chronic odontiod fracture, 1, odontiod absence, 1 fasilar impression, and 1 malunion of odontoid fracture. According to Symon and Lavenders classification of disability, 6 cases were moderate disability, 3 severe nonbedbound, and 1 severe bedridden. The procedure was performed by the same surgeon (Yong-Long Chi). Results The new technique was performed successfully in all cases. All the patients underwent transarticular screw fixation and anterior morselized autograft fusion. The average operation time was 120 min (range, 90 to 150 min) and the mean estimated blood loss was 150 mL (range, 100 to 250 mL). Postoperative radiographs demonstrated that 9 cases restored anatomic position and 1 had partial reduction. According to the postoperative computed tomography all the screws were appropriately placed. Follow-up after surgery, longest is 16 months and minimal 8 months with a mean of 12 months, neurologic status was improved in all patients. There was no loss of fixation and solid fusion was achieved in all cases. Conclusions Surgical technique of microendoscopic anterior release, reduction, fixation, and fusion is safe and reliable minimally invasive for treating IADD.

Autologous Olfactory Lamina Propria Transplantation for Chronic Spinal Cord Injury: Three-Year Follow-Up Outcomes From a Prospective Double-Blinded Clinical Trial.

We did a clinical trial to determine whether olfactory mucosa lamina propria (OLP) transplants promote regeneration and functional recovery in chronic human spinal cord injury (SCI). The trial randomized 12 subjects to OLP transplants (n = 8) or control sham surgery (n=4). The subjects received magnetic resonance imaging (MRI), electromyography (EMG), urodynamic study (UDS), American Spinal Injury Association impairment scale (AIS), and other functional assessments. OLP-transplanted subjects recovered more motor, sensory, and bladder function compared to sham-operated subjects. At 3 years after OLP transplant, one patient improved from AIS A to C and another recovered from AIS A to B, two recovered more than three segmental sensory levels, two had less spasticity, two had altered H-reflexes and SSEP, two regained bladder and anorectal sensation and had improved bladder compliance on UDS. OLP-treated patients had partial or complete tissue bridges at the injury site compared to cavitary gaps in sham-operated patients. The limited recovery suggests that OLP transplants alone do not have significant benefits but may provide a rationale for larger randomized trials or combination therapies.

Analysis of differentially expressed lncRNAs in differentiation of bone marrow stem cells into neural cells.

Many studies have reported micro RNAs involved in the differentiation of bone marrow mesenchymal stem cells (BMSCs) into neural cells; however, the roles of long non-coding RNAs (lncRNAs) in the differentiation of BMSCs into neural cells remain poorly understood. We used microarray assays to compare the lncRNA and messenger RNA (mRNA) expression profiles in BMSCs and neural-induced BMSCs. We found a total of 24 lncRNAs and 738 mRNAs that were upregulated and 32 lncRNAs and 682 mRNAs that were downregulated in samples induced for 3h; 27 lncRNAs and 864 mRNAs that were upregulated and 37 lncRNAs and 968 mRNAs that were downregulated in 6h samples; and 23 lncRNAs and 1159 mRNAs that were upregulated or downregulated in both the 3h and 6h samples. For 23 differentially lncRNAs and 83 differentially mRNAs, 256 matched lncRNA-mRNA pairs were found. GO (Gene ontology) analysis showed that these lncRNAs were associated with biological processes, cellular components, and molecular functions. Twenty-five pathways were identified by pathway analysis. Then, RT-qPCR validation of the differentially expressed H19, Esco2, Pcdhb18, and RGD1560277 genes confirmed the microarray data. Our study revealed the expression patterns of lncRNAs in the differentiation of BMSCs into neural cells, and many lncRNAs were differentially expressed in induced BMSCs, suggesting that they may play key roles in processes of differentiation. Our findings may promote the use of BMSCs to treat neurodegenerative diseases and trauma.

Percutaneous posterior transdiscal oblique screw fixation with lateral interbody fusion: a radiological and cadaveric study

PurposeTo design and investigate a novel technique of percutaneous posterior transdiscal oblique screw fixation with lateral interbody fusion.MethodsCT scans of 45 patients were collected and imported into Mimics software for three-dimensional (3D) reconstruction. Cylinders were drawn to simulate the trajectory of the oblique screw. Six measurements were obtained for each unit to design a right size cage: a the distance between the intersection of the simulated trajectory of the screw with the inferior border of the upper vertebra and its anteroinferior corner; b the distance between the intersection of the simulated trajectory of the screw with the superior border of the inferior vertebra and its anterosuperior corner; h the height of the intervertebral space; θ the angle between simulated trajectory of screw and the upper endplate of inferior vertebra; uw: the width of the inferior endplate of upper vertebra; iw: the width of upper endplate of inferior vertebra. Three intact adult fresh-frozen cadaveric specimens were obtained, percutaneous posterior transdiscal oblique screw fixation was performed under X-ray apparatus, and interbody cage was implanted by assistance with special self-retaining retractor system and endoscope.ResultsAccording to the results of data measured from 3D images, trapezoid shape interbody cages with suitable size were designed. Percutaneous posterior oblique screw fixation with lateral interbody fusion was performed on three cadaveric specimens successfully.ConclusionUsing specially designed trapezoid shape interbody cages, assisted by intra-operative image intensification and endoscope, it is feasible to perform percutaneous posterior transdiscal oblique screw fixation with lateral interbody fusion technique.

Induced human bone marrow stromal cells differentiate into neural cells by bFGF and cocultured with olfactory ensheathing cells.

Bone marrow stromal cells (BMSCs) were considered as one of the strongest candidates for cell transplantations to treat neurological disorders. Previously, we had showed that BMSCs isolated from rats could be induced to differentiate into neural cells being cocultured with olfactory ensheathing cells (OECs). In this study, we further demonstrated the neural differentiation of human BMSCs (hBMSCs) when cocultured with OECs and daily supplement of bFGF (basic fibroblast growth factor). Transwell culture dishes with a 0.4-mm pore size were used to coculture hBMSCs and OECs. At different time points (12h, 24h, 3d, 7d, 14d), the induced hBMSCs were morphologically observed and performed immunocytofluorescence and quantitative RT-PCR (qRT-PCR). The number of neural markers-positive cells significantly increased after coculture, and gene expression of NSE, β-III-tubulin, MAP2, GFAP also dramatically increased. Our study suggested that hBMSCs could be induced into neuron-like cells under conditions of coculture with OECs and daily supplement of bFGF. The differentiated autologous hBMSCs had a great potential for transplantation to treat CNS lesion.

Management of acute combination atlas–axis fractures with percutaneous triple anterior screw fixation in elderly patients

INTRODUCTION Patients with combined C1-2 fractures were often treated by posterior arthrodesis. However, elderly patients with multiple injuries (such as brain injury), the large surgical trauma of posterior arthrodesis will increase the risk of perioperative mortality. A minimally invasive technique may be better for them, and decrease the risk of perioperative mortality. MATERIALS AND METHODS Seven patients with combined C1-2 fractures underwent percutaneous anterior odontoid screw and anterior C1-2 transarticular screws (percutaneous triple anterior screws fixation). The surgical technique of percutaneous triple anterior screws fixation is described. RESULTS The operation performed on all patients successfully without technical difficulties, and no intra-operative surgery-related complications such as vertebral artery, nerve injury and soft tissue complications occurred. No pullout, loosening, or breakage of internal screws was observed. C1/2 stable was found in all cases and radiographic union achieved in all odontoid fractures. CONCLUSION Using the appropriate instruments allied to intra-operative image-intensification, we suggest that percutaneous triple anterior screw fixation is reliable, effective and minimally invasive procedure for elderly and brain injured patients suffering of combined atlas-axis fractures. LEVEL OF EVIDENCE Level IV. Retrospective study.

The Outcomes of Minimally Invasive versus Open Posterior Approach Spinal Fusion in Treatment of Lumbar Spondylolisthesis: The Current Evidence from Prospective Comparative Studies

Purpose. To investigate the evidence of minimally invasive (MI) versus open (OP) posterior lumbar fusion in treatment of lumbar spondylolisthesis from current prospective literatures. Methods. The electronic literature database of Pubmed, Embase, and Cochrane library was searched at April 2016. The data of operative time, estimated blood loss and length of hospital stay, visual analog scale (VAS) of both lower back pain and leg pain, Oswestry disability index (ODI), SF-36 PCS (physical component scores) and SF-36 MCS (mental component scores), complications, fusion rate, and secondary surgery were extracted and analyzed by STATA 12.0 software. Results. Five nonrandom prospective comparative studies were included in this meta-analysis. The meta-analysis showed that the MI group had a significantly longer operative time than OP group, less blood loss, and shorter hospital stay. No significant difference was found in back pain, leg pain, ODI, SF-36 PCS, SF-36 MCS, complications, fusion rate, and secondary surgery between MI and OP groups. Conclusion. The prospective evidence suggested that MI posterior fusion for spondylolisthesis had less EBL and hospital stay than OP fusion; however it took more operative time. Both MI and OP fusion had similar results in pain and functional outcomes, complication, fusion rate, and secondary surgery.