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Abstract Objectives To identify age-related radiographic risk factors for degenerative lumbar spinal stenosis (DLSS) and analyze correlations among them. Methods A total of 180 cases were enrolled in this study, and lumbar magnetic resonance was performed. Among them, 93 cases suffered DLSS and lumbar dynamic X-ray was examined. And following parameters were measured and evaluated: intervertebral disk height (IDH), the ratio of IDH(IDHL4-5/L3-4), initial IDH of L4-5(iIDHL4-5) in the DLSS group, disk degeneration (DD), cartilaginous endplate failure (CEF), Modic changes, the thickness of ligamentum flavum (LF), range of intervertebral motion (ROM), facet joint opening (FJO), facet joint angle (FJA), the standard cross-sectional area (SCSA) of the multifidus, erector spinae, and psoas major muscles. The data of two groups were compared, and the possible risk factors of DLSS were analyzed. Results Compared with the control group, the DLSS group had higher IDH except for L4-5 and larger iIDHL4-5 (P

Abstract Background We aimed to analyze the clinical results of Schwab grade 4 osteotomy combined with percutaneous pedicle screws (PPS) fixation for treatment of post-traumatic thoracolumbar kyphosis (PTK). Methods Thirty four patients with PTK (group A) were included in our study. The average age was 54.9 ± 3.3 years. All patients had severe back pain with 8.6 ± 1.3 VAS scores. The affected level was T12 in 16 patients and L1 in 18 patients. The average preoperative regional kyphosis angle (RKA) was 30.7 ± 6.00. Three patients had neurological dysfunction with ASIA grade D. All patients underwent Schwab grade 4 osteotomy combined with PPS fixation. The control group (Group B) were 26 PTK patients treated with Schwab grade 4 osteotomy and open pedicle screws fixation in our institution. Results Operation time in groups A and B was 280 ± 50 min and 210 ± 30 min, respectively (P 0.05). CT showed that the misplacement rate in groups A and B was 5.5 and 6.6% (P > 0.05). The average follow-up in groups A and B was 25.2 ± 7.6 months and 30.6 ± 2.7 months. No fracture and other complications were observed in both groups. Solid bone fusion was showed in all cases at 6 months follow-up. In groups A and B, all patients with preoperative neurological dysfunction recovered to ASIA grade E at the last follow-up. The VAS score of back pain improved significantly from 8.6 ± 1.3 to 1.6 ± 1.0 at the last follow-up in group A (P

Abstract Background Percutaneous vertebroplasty is the most common treatment for osteoporotic vertebral compression fracture. However, the morbidity of vertebroplasty-related complications, such as cement leakage, remains high. We tested a new technique of unilateral pulsed jet lavage and investigated its effect on the intravertebral pressure and bone cement distribution. Methods Thirty lumbar vertebrae (L1-L5) from six cadaver spines were randomly allocated into two groups (with and without irrigation). Prior to vertebroplasty, pulsed jet lavage was performed through one side of the pedicle by using a novel cannula with two concentric conduits to remove the fat and bone marrow of the vertebral bodies in the group with irrigation. The control group was not irrigated. Then, standardized vertebroplasty was performed in the vertebral bodies in both groups. Changes in the intravertebral pressure during injection were recorded. Computed tomography (CT) was performed to observe the cement distribution and extravasations, and the cement mass volume (CMV) was calculated. Results During cement injection, the average maximum intravertebral pressure of the unirrigated group was higher than that of the irrigated group (4.92 kPa versus 2.22 kPa, P < 0.05). CT scans showed a more homogeneous cement distribution with less CMV (3832 mm3 vs. 4344 mm3, P < 0.05) and less leakage rate (6.7% vs. 46.7%, P < 0.05) in the irrigated group than in the control group. Conclusions Unilateral pulsed jet lavage can reduce intravertebral pressure and lower the incidence of cement leakage during vertebroplasty. An enhanced bone cement distribution can also be achieved through this lavage system.

Abstract Background Recently, the excellent outcomes of temporary fixation of C1-2 without fusion in the treatment of odontoid fracture had been reported. It is still unclear if this technique could achieve the equivalent outcomes as the golden standard technique of anterior screw fixation. The objective of this study is to compare the clinical outcome of two treatments of fresh type II odontoid fracture: anterior cannulated screws fixation (ACSF) versus posterior instrumentation of C1-2 without fusion (PIWF). Methods This is a retrospective study. This series included 28 males and 8 females, and the mean age was 41.5 years (range, 22 to 70 years). Eleven patients were treated with ACSF, and 25 patients with PIWF. For PIWF, the implants were removed after fracture union was confirmed at 0.75~1.5 years later. All patients underwent preoperative and serial postoperative clinical examinations at approximately 3 months, 6 months, and annually thereafter. The neck disability index (NDI) was used to assess the neck discomfort caused by the operation. The range of rotary motion was evaluated at each visit. All fractures were reassessed postoperatively with serial X-films and CT scans of the cervical spine at each follow-up visit, to evaluate screw position, fracture alignment, and fusion status. Results All patients achieved immediate spinal stabilization after surgery, and none experienced neurologic deterioration. The follow-up periods ranged from 24 to 60 months. The average range of neck rotation was dramatically lost in PIWF after fixation (46° and 89° respectively in ACSF and PIWF), and recovered to 83° after the implant was removed. The NDI in PIWF was statistically higher than that in ACSF (5 and 13% respectively in ACSF and PIWF) after the first operation and decreased to 8% 1 year after the secondary operation. The fusion rates were 90.9 and 96% respectively in ACSF and PIWF. Both groups had a case of fracture non-union. Conclusions For fresh type II odontoid fractures, high rate of fracture union can be achieved by both ACSF and PIWF. For most fresh type II odontoid fractures, anterior screw fixation was the best option for its simplicity and preservation of normal atlanto-axial rotary function. Posterior instrumentation without fusion could preserve most of the atlanto-axial rotary function and lead to moderate neck discomfort and is also a good alternative if anterior screw fixation is contraindicated.

Several major vascular tissues, such as the aorta-gonad-mesonephros región (AGM), yolk sac, and fetal liver have been confirmed to possess hematopoietic function. Recently, the placenta has been demonstrated as another hematopoietic organ. However, it is not conclusive whether the placenta possesses hematopoietic ability. Therefore, we undertook a series of experiments to study the hematopoietic functions of placenta. Fetal blood circulation in the placenta is difficult to be eliminated and its interference in the study of placental hematopoiesis is inevitable. With the application of placental flushing, fetal blood contained in the placenta was eliminated. We then made the further study of placental hematopoiesis after the El2.5 placenta was flushed. Our studies showed that placental cells expressing Sca-1, CD117 and CD34 were mainly restricted to the embryonic vessels of E12.5 placenta. The results of fluorescence activated cell sorter (FACs) analysis and colony forming cells (CFC) assay demonstrated that both placenta and placental blood contained hematopoietic stem/progenitor cells (HS/PCs), including CFU-GMs, CFU-GEMMs, BFU-Es, and HPP-CFCs. The frequency of HS/PCs in the placenta was 2-3 times that of placental blood. Therefore, it is necessary to clear placental blood out of the placenta in the studies of the hematopoietic potential of placenta. The placenta still possessed the hematopoietic potential after the fetal blood is flushed out. These observations provide further evidences that the placenta is a hematopoietic organ, as has been proposed for other embryonic hematopoietic sites.