Fu Zg

Bone marrow stromal cells differentiated into functional Schwann cells in injured rats sciatic nerve.

Bone marrow stromal cells (MSCs) have been shown to differentiate into various lineage cells including neural cells in vitro and in vivo. We therefore examined whether MSCs can differentiate into Schwann cells in injured peripheral nerves. After cultured in vitro, PKH-67-labeled MSCs were injected into the mechanically injured rat sciatic nerves. Three weeks after injection, immunofluorescent examinations were carried out. MSCs had been incorporated around the injured nerves and differentiated into Schwann cells. MSCs had accumulated mainly in the epineurium around the injured nerve. The incorporated cells partially expressed GFAP, S-100, and P75. These results confirmed the possibility that MSCs have the ability to differentiate into Schwann cells, and that injection of MSCs into the injured peripheral nerve would help repair damaged nerve.

Accurate Determination of Isthmus of Lumbar Pedicle : A Morphometric Study using Reformatted Computed Tomographic Images

Study Design. Lumbar pedicle isthmus, the narrowest section of pedicle, was investigated. Objective. To determine the lumbar pedicle isthmus accurately and measure related parameters. Summary of Background Data. Accurate anatomic knowledge of pedicle parameters is critical for a successful transpedicular procedure. Many studies on lumbar pedicle dimensions have been conducted, yet less is known about how to obtain these data and their veracity. In fact, the narrowest section is present in the pedicle, i.e., the isthmus of the pedicle. This is the bottleneck of the pedicle; to determine and measure it could illustrate the true morphologic characteristics of the lumbar pedicle. Methods. Ultra high-speed spiral CT scan of lumbar spine was performed in 41 patients of Chinese origin. After reformation of the original images, isthmus and transverse plane of pedicle axis were determined. Eleven dimensions of isthmus plane and three dimensions of transverse plane were calculated using software. Results. Pedicle endosteal width and height in female patients who were over the age of 50 were greater than those of female patients younger than 50 years old. The isthmus endosteal width from L1 to L5 was 5.2, 6.0, 7.5, 7.5, and 8.7 mm and 4.0, 4.1, 5.4, 5.7, and 7.1 mm, respectively, in men and women. Isthmus inclination inclined to midline with less than 10° above L3 but increased in L4 and 30° in L5. Conclusions. An objective narrowest section, the pedicle isthmus, exists in lumbar pedicle axis. The parameters of isthmus, especially isthmus endosteal width, show the morphologic characteristics of the lumbar pedicle and are the most important data provided for transpedicular procedures. The small pedicles of female patients over the age of 50 also show certain primary osteoporosis. Isthmus inclination puts the pedicle in a more complicated space position. A better understanding of the complicated structure of the pedicle isthmus guarantees success in transpedicular procedures.

Effect of Calcar Screw Use in Surgical Neck Fractures of the Proximal Humerus With Unstable Medial Support: A Biomechanical Study.

Objectives: To evaluate the effect of calcar screw use in proximal humeral fractures with unstable medial support treated with locked plates. Methods: Standard osteotomies were performed in 36 cadaveric humeri to create a surgical neck fracture proximal humeral model. For static testing, 12 pairs of humeri were divided into 4 groups: normal alignment and varus deformity groups with and without 5-mm medial deficiencies. Calcar screw function was measured in each group by axial, shear, and torsion stiffness tests. Another 6 pairs of humeri with 5-mm medial deficiencies were subjected to cyclic loading tests in the normal alignment model with and without calcar screw application. Results: Calcar screws improved rotational stability in the normal alignment (P = 0.007) and varus (P = 0.002) groups. Calcar screws improved static and cyclic axial (P = 0.004) and shear (P = 0.017) stability in the normal alignment group with medial deficiency. In specimens with normal alignment and intact medial cortex, calcar screws provided no advantage in axial (P = 0.535) or shear (P = 0.537) stiffness. Calcar screws did not provide sufficient axial (P = 0.782) or shear (P = 0.772) stability to avoid reduction loss in humeri with varus malreduction. Conclusions: In humeri with normal alignment, calcar screws can provide additional stability even when a medial deficiency exists. The use of calcar screws in humeri with varus deformity showed no biomechanical superiority.

The Experimental Study of Absorbable Chitin Conduit for Bridging Peripheral Nerve Defect with Nerve Fasciculu in Rats

To investigate the possibility of constructing artificial peripheral nerves using de-acetyl chitin conduit, the sciatic nerves defect model was built at left legs in SD rats. They were divided into 3 groups randomly: group A: nerve graft in situ (n = 12, gap distance 10 mm); group B: biological chitin conduit bridging the peripheral nerve defect (n = 12, gap distance 10 mm); group C: biological chitin conduit bridging the peripheral nerve defect with nerve fibers in conduits (n = 12, gap distance 10 mm). Electrophysiological examination, histological examination and re-myelinated axons counting were applied after 6th and 12th week after operation, respectively. Regenerated nerve fibers were seen in the distal nerve segments of all three groups. The nerve conduction velocity and the re-myelinated axons counting of group A were better than that of group C at both 6th and 12th week time points (p < 0.05). The nerve conduction velocity and the re-myelinated axons counting of group C were better than that of group B at both 6th and 12th week time points (p < 0.05). The repair effects of chitin conduit with nerve fibers in conduit bridging peripheral nerve defect (10 mm) were better than that of simple conduit bridging group, and that of group A (nerve graft group) was better than that of group C.

Effects of Hedysari Polysaccharides on Regeneration and Function Recovery Following Peripheral Nerve Injury in Rats

It has been demonstrated that aqueous extract of Radix Hedysari Prescription and modified Radix Hedysari Prescription could improve the regeneration of injured peripheral nerve. Radix Hedysari is a main component in these two formulas. We hypothesized that Hedysari polysaccharides (HPS), a main active ingredient, could also enhance peripheral nerve regeneration after nerve injury in adult animals. In the present study, we examined the effects of HPS on sciatic nerve regeneration for 6 weeks following clamping in rats (administrated orally of 2 ml HPS liquid daily, 0.25 g/ml). The results showed that HPS was able to enhance sciatic function index (SFI) value, tibial function index (TFI) value, peroneal nerve function index (PFI) value, conduction velocity, and the number of regenerated myelinated nerve fibers, suggesting the potential clinical application of HPS for the treatment of peripheral nerve injury in humans.

Randomized Prospective Study of Olecranon Fracture Fixation: Cable Pin System versus Tension Band Wiring

OBJECTIVE: This prospective, randomized study compared the effectiveness of the cable pin system (CPS) versus tension band wiring (TBW) for olecranon fracture fixation. METHODS: Patients with acute transverse or slight oblique olecranon fractures were randomly divided into two groups: one fixed by CPS and the other by TBW. Clinical outcome data were collected and analysed following a mean duration of 21 months. RESULTS: The mean ± SD fracture healing time was significantly shorter in the CPS group (n = 30; 9.73 ± 2.02 weeks) compared with the TBW group (n = 32; 11.13 ± 2.21 weeks). One patient in the CPS group and seven patients in the TBW group experienced postoperative complications; this difference was statistically significant. The mean ± SD Mayo Elbow Performance Score in the CPS group was significantly higher (88.67 ± 6.42) than that in the TBW group (80.78 ± 11.99). Logistic regression analysis showed an association between fixation method and fracture healing time, complications and elbow function. CONCLUSIONS: Internal fixation by CPS is an effective method for olecranon fracture and is associated with a shorter healing time, fewer complications and better function than TBW.

Radiological evaluation of reduction loss in unstable proximal humeral fractures treated with locking plates.

PURPOSE The aim of this study was to radiologically evaluate the risk of reduction loss after locking plate fixation of proximal humerus fractures. METHODS From September 2007 to April 2009, 71 patients (28 males, 43 females) with unstable proximal humeral fracture were treated with open reduction and internal fixation by locking plate. The mean follow-up time was 31.2 months (range: 26-47). The head-shaft angulation (HSA) and the humeral head height (HHH) in true anteroposterior (AP) were recorded and compared over time. All complications were noted. Shoulder function was measured by the Constant score. RESULTS Patients with ΔHSA >10° (t=2.740, P=0.008) and ΔHHH >5mm (t=2.55, P=0.019) were more likely to have impaired shoulder function. Varus collapse occurred most frequently in patients with initial reduction of HSA <125° (χ(2)=19.17, P<0.001, Fishers exact test F<0.001). Patients with >5mm HHH decrease were strongly associated with loss of reduction (χ(2)=24.23, P<0.001, F<0.001). CONCLUSIONS Dynamic change of HSA >10° and HHH >5mm were radiological factors that indicated poor shoulder function. Intra-operative HSA >125° should be achieved to avoid reduction loss following locking plate fixation of proximal humerus fracture. LEVEL OF EVIDENCE level IV.

Incidence of venous thromboembolism and hemorrhage related safety studies of preoperative anticoagulation therapy in hip fracture patients undergoing surgical treatment: a case–control study

BackgroundVenous thromboembolism is a common postoperative complication following orthopedic surgeries, with morbid and potentially fatal consequences. Perioperative low-molecular-weight heparin (LMWH) therapy can reduce the incidence of venous thromboembolism, but may also increase the risk of bleeding complications. Current literature reflects the need to balance the improved efficacy of early initiating prophylaxis with increased risk of perioperative bleeding. The purpose of this study was to compare the effectiveness and hemorrhage related safety of preoperative versus postoperative LMWH therapy for prevention of deep venous thrombosis (DVT) and pulmonary embolism (PE) in hip fracture patients.MethodsWe retrospectively evaluated 222 patients who underwent surgical treatment at Peking University Peoples Hospital between January 2009 and December 2010. Patients were allocated to two groups, receiving either preoperative or postoperative initiation of LMWH therapy for venous thromboembolism prophylaxis. Preoperative anticoagulation therapy was initiated 1–12 days prior to surgery (133 patients), and postoperative anticoagulation therapy was initiated 12 h after completion of surgery (89 patients). The preoperative group was further subdivided into four subgroups according to the time of initiation of therapy: 1–3 days before surgery (group A, 54 patients), 4–6 days before surgery (group B, 57 patients), 7–9 days before surgery (group C, 15 patients), and 10–12 days before surgery (group D, 7 patients). Occurrences of DVT, PE, adverse drug effects, intraoperative and postoperative bleeding were recorded, along with concentrations of preoperative and postoperative hemoglobin and length of hospital stay. The above parameters were compared between groups.ResultsAmong recipients of preoperative anticoagulation therapy, two patients developed postoperative PE (1.5 %), one patient developed DVT (0.75 %). In the group receiving postoperative initiation of anticoagulation therapy, one patient each developed PE and DVT (1.1 %, 1.1 %). There was no difference in the occurrence of PE and DVT between the two groups (P>0.05, Chi-square tests). We identified the incidences of major bleeding, minor bleeding, and intraspinal hematoma after spinal anesthesia, which were 0 %/0 %, 3.76 %/3.37 %, and 0 %/0 %, respectively in preoperative and postoperative anticoagulation groups. There was no significant difference in the incidence of bleeding complications between patients receiving preoperatively initiated LMWH with patients receiving postoperatively initiated LMWH. Spinal anesthesia was administered to 168 patients, with no cases of postoperative intraspinal hematoma.ConclusionsPreoperative anticoagulation therapy with LMWH may not increase intraoperative or postoperative blood loss, or the rate of intraspinal hematoma after spinal anesthesia, but also does not significantly reduce the risk of postoperative DVT or PE, compared to postoperative initiation.

Biomechanical Evaluation of a New Device for Internal Fixation of Femoral Neck Fractures

Abstract: This study aimed to compare the fixation stability of a new device (SCCAB) for femoral neck fractures and the cancellous lag screws. Standardized femoral neck osteotomies were created in seven pairs of cadaver femurs and stabilized with either SCCAB or cancellous lag screws. The specimens were subjected to incremental axial loading to 1300 N and cyclic loading at 1300 N for 104 cycles. No significant differences in downward femoral head displacement, change in the superior osteotomy gapping, and load to failure were observed between the two groups. SCCAB may be potentially useful to treat femoral neck fractures.

EGFP Expression Controlled by GFAP Promoter in Mesenchymal Cells: An Efficient Tool for Glial Lineage Selection and Transplantation

In order to demonstrate a new method to label and select enough glial cells from induced MSCs to provide cells for cell therapy, MSCs were induced with Beta-mercaptoethanol followed by retinoic acid, forskolin, basic-FGF, PDGF and heregulin. Induced MSCs were transfected with reconstructed vector pGFAP-EGFP by inserting GFAP promotor into pEGFP-N3 to substitute CMV promotor. Living cells against G418 were enriched and checked by flowcytometry. EGFP expressing cells were sorted and used for transplantation in vivo. Immunoelectronmicroscopy was accomplished using anti-EGFP to relocalize the transplanted cells. Almost all MSCs took on phenotypes of glial cells after induction, expressing S100 and GFAP. The EGFP expression rate of survived MSCs against G418 was 82.74%. Glial cells expressing EGFP accumulated mainly around the damaged nerve fibers. MSCs were relocalized by immunoelectronmicroscopy and remyelination was observed. EGFP expression controlled by GFAP promoter in mesenchymal cells was an efficient tool for glial lineage selection and transplantation. Induced MSCs can promote nerve regeneration by participating remyelination.