Clinical characteristics of patients with spontaneous spinal epidural hematoma / 中华神经医学杂志

Objective To explore the etiology,clinical presentation and treatment of patients with spontaneous spinal epidural hematoma (SSEH). Methods Twelve patients diagnosed as having SSEH, admitted to our hospital from January 1995 to December 2010, were chosen in our study; 10 underwent surgical operation and 2 chose conversational therapy; the characteristics of onset,clinical presentations, diagnosis, treatment and results of follow-up were analyzed. Results No obvious reasons induced the onset of SSEH in these patients and all manifested as loss/decrement of myodynamia of the involved limbs,and bowel and bladder dysfunctions.Follow-up was performed for 6-18 months; 2 patients received hematoma lesion dissection by spinal canal decompression enjoyed entire recovery of neural dysfunction, while 8 showed no significant amelioration in spinal cord function besides mild improvement of bowel and bladder function; in the 2 patients chosing conversational therapy,1 achieved total recover of the nerve funtion and the other one partially recovered. Conclusion The etiology of SSEH remains indefinite and the prognosis is usually disappointed; permanent spinal cord dysfunction is seemly inevitable in most cases; prompt surgical intervention are of great importance for prognosis of SSEH and should be the first choice of therapy.

Pullout test in expansive unilateral open-door laminoplasty of the cervical spine with OsteoMed M3 plate and screws: the screw orientation matters / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the impact of screw orientation on the pullout strength of OsteoMed M3 titanium screws in expansive unilateral open-door laminoplasty of the cervical spine.</p><p><b>METHODS</b>Six fresh human cervical spine specimens were randomly numbered and OsteoMed M3 plate and screws were used for an expansive unilateral open-door laminoplasty. The screws were inserted in the lateral mass at different extraversion angles (0°, 30° and 45°). The maximum pullout strength was tested on the ElectroForce material testing machine.</p><p><b>RESULTS</b>The maximum pullout strength was 81.60∓7.33 N, 150.05∓15.57 N, and 160.08∓17.77 N in extraversion angle 0°, 30°, and 45° groups, respectively. The maximum pullout strength was significantly less in extraversion angle 0° group than in 30° and 45° groups (P<0.05), but similar in the latter two groups.</p><p><b>CONCLUSION</b>The pullout strength of the screws inserted at an extraversion angle over 30° provides stronger fixation than an angle of 0° in the unilateral open-door laminoplasty using OsteoMed M3 titanium plate and screws.</p>

Differentiation of spinal cord derived neural stem cells modified by BDNF gene / 中华神经医学杂志

Objective To study the differentiation potential of mouse spinal cord derived neural stem cells (NSCs) into neurons after being transfected with BDNF gene in vitro. Methods Spinal cord derived NSCs from the E14 fetus mouse were isolated and cultured in vitro; the retrovirus containing pLXSN-BDNF gene was established and transfected into thc above NSCs, and thea, spinal cord derived NSCs were induced to be differentiated into neuron-like cells. Immunohistochemistry was employed to detect and calculate the ratio of differentiation of NSCs into neurons. Results The NSCs cultured in vitro partly adhered to the wall and differentiated within 24 h of transfection with BDNF gene, and most of the NSCs adhered to the wall differentiated within 48 h of transfection. The level of neurons from spinal cord derived NSCs modified by BDNF gene was markedly increased as compared with that that from normal spinal cord derived NSCs (P＜0.05). Conclusion NSCs transfected by retroviral pLXSN-BDNF can promote the cell differentiation. BDNF gene can increase greatly the percentage of neurons in the course of inducing the differentiation of mouse NSCs.

Indication of fusion for degenerative lumbar spinal stenosis treated by "windows technique" laminoforaminotomy / 中华外科杂志

<p><b>OBJECTIVE</b>To explore the indications of fusion for degenerative lumbar spinal stenosis treated by "windows technique".</p><p><b>METHODS</b>From December 1999 to December 2005, 145 consecutive patients who were treated by primary decompression with "windows technique" laminoforaminotomy for degenerative lumbar spinal stenosis, a retrospective study, were divided into 3 groups (A and B and C) by preoperative lumbar conditions and surgical methods. In group A, 39 patients with spinal instability or degenerative lumbar spondylolisthesis or scoliosis underwent decompression and fusion; in group B, 31 patients with spinal instability or degenerative lumbar spondylolisthesis or scoliosis underwent decompression alone; In group C, 75 patients without spinal instability or degenerative lumbar spondylolisthesis or scoliosis were treated by decompression without fusion. On hospital medical records to review, they were followed up by telephone and out-patient referral. Statistics the duration of hospitalization, operative time, estimated blood loss; Observed recrudescence and reoperation and complication; and using Oswestry Disability Index and Visual Analog Scale and satisfaction rate for efficacy assessment, application SPSS 13.0 software.</p><p><b>RESULTS</b>All 145 patients had at least a 3-year follow-up (ranging 37 to 108 months). In the group C, the duration of hospitalization less than in the group A or B (P < 0.05); In the group A, the operative time and estimated blood loss greater than in the group B or C (P < 0.05); The group B treated by decompression alone in the presence of instability or spondylolisthesis or scoliosis showed the worst results by the Oswestry Disability Index or Visual Analog Scale or ate of satisfaction (P < 0.05). The same good results can be obtained in the group A and C. There were not different about recrudescence or reoperation or complication in the three groups.</p><p><b>CONCLUSIONS</b>Fusion should be performed on patients with instability or degenerative lumbar spondylolisthesis or scoliosis after primary decompression with "windows technique" laminoforaminotomy. The patient with simple lumbar spinal stenosis undergone primary surgery does not require fusion.</p>

Effect of continuous passive motion on basic fibroblast growth factor expression during tendon-bone repair after surgical repair of acute rupture of the supraspinatus tendon in rabbits / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the effect of continuous passive motion (CPM) on basic fibroblast growth factor (b-FGF) expression during tendon-bone repair in rabbits and explore the role of stress in the postoperative repair after acute rotator cuff injury.</p><p><b>METHODS</b>Sixteen rabbits randomized into CPM group (n=8) and non-CPM group (n=8) were subjected to surgically induced acute rupture of the supraspinatus tendon and subsequent surgical repair, with another two rabbits serving as the control. Two weeks after the operation, the rabbits in CPM group underwent CPM training, and those in non-CPM group were normally fed only. At 2, 4, 6, and 8 weeks after the operation, 2 rabbits from each group were sacrificed and the tissue samples were obtained for detecting the changes in b-FGF expression.</p><p><b>RESULTS</b>Two weeks after the operation, b-FGF expression was detected in both groups, and the CPM group showed slightly higher and more diffusive expression. At 4 weeks, b-FGF expression was significantly higher and distributed over a greater area in CPM group and in the non-CPM group. A large number of fibroblasts positive for b-FGF expression were identified in CPM group, aligning in parallel with the tendon membrane. At 6 weeks, b-FGF in the CPM group showed no obvious changes but that in the non-CPM group became lightened. At 8 weeks, b-FGF expression was reduced in both groups, which was more obvious in the non-CPM group.</p><p><b>CONCLUSION</b>CPM can promote b-FGF expression to enhance type III collagen synthesis at the tendon-bone interface in early stage of tendon-bone repair following acute rupture of supraspinatus tendon in rabbits, thereby contributing to tendon-bone recovery after rotator cuff injury.</p>

Three-dimensional visualization of the structures related to the anterior cervical segment approach / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish a digital model allowing three-dimensional visualization of the structures involved in the anterior cervical segment approach.</p><p><b>METHODS</b>Based on the imaging data obtained from CT angiography (CTA), magnetic resonance myelography (MRM) and continuous magnetic resonance imaging (MRI) of a healthy volunteer (scanning from the center of the head to the inferior border of the T3 level), image segmentation and reconstruction for the skeleton, arteries, veins, and spinal cord was conducted semi-automatically using the Mimics software according to the different thresholds of the tissues. The cervical plexus, brachial plexus and muscles of the neck were reconstructed with the Nerves pipe editor and the Med CAD module to establishing the three-dimensional model for displaying the structures involved in the anterior cervical segment approach.</p><p><b>RESULTS</b>A three-dimensional digital model of the structures involved in the anterior cervical segment anterior approach was established, which allowed the display of anatomical relations of the skeletal structure, aorta, superior vena cava, thyroid gland, hyoid bone, laryngeal cartilages, trachea, lung, 12 neck muscle groups, as well as the spinal cord, spinal nerves, cervical plexus, brachial plexus, and intervertebral disk of the neck.</p><p><b>CONCLUSION</b>The three-dimensional model established can allow the visualization of the important structures for the anterior cervical segment approach, and provides a medical teaching platform for anatomy and surgical training.</p>

Placement of short iliac screw using Galveston technique in lumbosacral fusion / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the effect of placement of short iliac screw using Galveston technique in lumbosacral fusion.</p><p><b>METHODS</b>From October 2003 to August 2007, 18 consecutive patients (mean age 46 years ranging from 25 to 62 years) received placement of short iliac screw in lumbosacral fusion. The patients were followed up for a mean of 18 months (12-23 months), and the effect of lumbosacral fusion was evaluated according to standing anterior-posterior and lateral plain films taken before and after the operation and at the follow-up and also on the basis of symptom relief.</p><p><b>RESULTS</b>The mean time of surgery was 210 min (180-290 min). No complications occurred during and after the operation. According to the evaluation criteria of surgical treatment of low back pain formulated by the spine group of Chinese Orthopedic Association, excellent clinical outcome was achieved in 12 cases, good outcome in 3 cases, and tolerable outcome in 2 cases, with the excellent and good outcome rate of 83%.</p><p><b>CONCLUSION</b>The Galveston technique for short iliac screw placement can obtain satisfactory outcome in the lumbosacral fusion.</p>

Effect of rotating magnetic field on pain threshold in rats' spinal cord:an analysis from processing time and angular velocity / 中华神经医学杂志

Objective To observe the effects of rotating magnetic field on the tail-flick latency (TFL)and mechanical withdrawal threshold(MWT)of rats and analyze it from processing time and angular velocity.Methods Forty-eight female SD rats were randomly assigned to 8 groups(n=6),which would be determined by 8 different time points(before treatment,treating for 10,20,30 and 60 min,10,20 and 30 min after treatment).The magnetic plate rotated near the lumbar of the rat at an angular velocity of 7300 r/min and the TFL and MWT with yon Frey hair test were determined at each time point.The second experiment was carried out on 40 female rats at an angular velocity of 6300,6800,7300 and 7800 r/min,respectively;TFL and MWT were determined 30 min after treatment.The data were statistically analyzed.Results The first experiment was concluded as follows:compared with that before treatment,TFL was statistically increased at treating for 10,20,30 and 60 min(P<0.05).The TFL gradually became shorten after the treatment,but it was still significantly longer 10 and 20 min after the treatment as compared with that before treatment(P<0.05).MWT increased significantly at treating for 30 and 60 min,and 10 min after treatment as compared with that before treatment(P<0.05).The second experiment showed that TFL significantly went up as the angular velocity increased(P<0.05).Significantly difference on MWT was found between the angular velocity of 7800 and 6300 r/min.Conclusion Pain threshold can be increased by rotating magnetic field following the increase of processing time and the angular velocity at a certain range,indicating that the rotating magnetic field might be a potential non-invasive pain alleviating method.

Biomechanical evaluation of asymmetrical posterior internal fixation for transforaminal lumbar interbody fusion with transfacetopedicular screws / 南方医科大学学报

<p><b>OBJECTIVE</b>To assess the biomechanical stability of asymmetrical posterior internal fixation for transforaminal lumbar interbody fusion (TLIF) with transfacetopedicular screws (TFPS).</p><p><b>METHODS</b>Range of motion (ROM) testing was performed in 7 fresh-frozen human cadaveric lumbar spine motion segments in flexion/extension, lateral bending, and axial rotation using 10.0 Nm torques at the L3-4 motion segment. The sequential test configurations included intact motion segment, TLIF and ipsilateral pedicle screw (PS), TLIF and ipsilateral PS plus contralateral TFPS according to Boucher technique, and TLIF and bilateral PS. The ROM was determined to assess the construct stability.</p><p><b>RESULTS</b>In flexion/extension, lateral bending, and axial rotation, no measureable difference was found in the ROM between the standard bilateral pedicle screw and the novel asymmetric posterior internal fixation after TLIF. After TLIF, the ipsilateral PS construct provided less segment stability than the novel asymmetric construct with TFPS in flexion, left bending and left rotation. In rotation, the novel asymmetric construct allowed for significant off-axial rotation motions detrimental to the stability and fusion.</p><p><b>CONCLUSION</b>Ipsilateral PS placement plus contralateral TFPS provides stability comparable to that of TLIF with bilateral PS, and can be an alternative in minimal invasive surgery.</p>

Biomechanical evaluation of the U shape lumbar biological dynamic fixation system / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate biomechanical characteristics of a new U-shaped lumbar bioelastic internal fixation deuice (UBD).</p><p><b>METHODS</b>Six fresh calf lumbar (L2-L5) samples were divided into 4 groups, namely the normal group, traumatic instability group, instability group with rigid internal fixation and instability group with UBD fixation. The vertebral 3-dimensional range of motion (ROM) and rigidity of the 4 group were tested.</p><p><b>RESULTS</b>Elastic fixation and rigid fixation both significantly increased vertebral segment stability for flexion, extension, lateral curvature and rotations. Compared with rigid fixation, elastic fixation obviously increased the ROM by 2.22 degrees in flexion and extension, but significantly decreased the rigidity in forward bending and backward bending and compression (P<0.01).</p><p><b>CONCLUSION</b>The UBD may enhance the load sharing and decrease stress-shielding and stress concentration without sacrificing lumbar stability.</p>

Construction of a three-dimensional lumbar spine model and its application in virtual surgery based on virtual reality technique / 中华神经医学杂志

Objective To construct a three-dimensional (3D) lumbar spine model to allow real-time complicated interactions in virtual lumbar surgery based on virtual reality technique. Methods The data of high-resolution CT slices were segmented and the contours were extracted. Surface rendering technique was adopted to construct of the lumbar spine model on the basis of serial contours, and the model was optimized according to the need of real-time interaction. Results The lumbar spine model with fewer polygons was characterized by high resolution and smoothness. After being loaded in the virtual surgery system, the model accurately displayed the anatomy of lumbar spine and allowed real-time interaction during the virtual surgery. Conclusion The 3D lumbar spine model constructed based on the CT slices is applicable for complicated interactions in virtual lumbar surgery.

Short-term clinical follow-up of metal-on-metal hip resurfacing arthroplasty / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the short-term outcome of patients receiving metal-on-mental hip resurfacing arthroplasty and analyze the factors affecting the result.</p><p><b>METHODS</b>In 13 patients receiving metal-on-metal hip resurfacing arthroplasties with scheduled follow-up, the treatment outcomes were assessed according to the Harris Hip Score.</p><p><b>RESULTS AND CONCLUSION</b>The short-term outcomes of hip resurfacing arthroplasties were encouraging, and intraoperative complications, infections, peripheral nerve palsy, hip dislocations or clinically overt lower limb deep vein thrombosis occurred in none of these cases. All the patients reported complete or major pain relief. Clinical assessment according to the Harris Hip Score revealed an improvement from an average score of 36.69 preoperatively to 89.63 after the surgery. Crutch use lasted for a maximum of 4 weeks postoperatively in these patients, after which the patients were all capable of walking without crutches with full weight-bearing.</p>

Recombinant human bone morphogenetic protein-2 promotes tendon-bone healing after anterior cruciate ligament reconstruction in rabbits / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) in promoting the tendon-bone healing in rabbits after anterior cruciate ligament reconstruction.</p><p><b>METHODS</b>Thirty normal adult New Zealand rabbits were divided into 3 groups for anterior cruciate ligament reconstruction using autologous semitendinosus tendons as the graft material. In the rhBMP-2 group, fibrin glue (FG) containing rhBMP-2 was applied to the interface between the tendon graft and the bone tunnel, while in the FG control group, only FG was applied. The blank control group received no treatment after the surgery. The grafts were collected at 2, 4, 8 weeks after the surgery for gross observation and histological examination of the graft incorporation.</p><p><b>RESULTS</b>In the FG control group, the tendon-bone interface was filled with granulation tissue 2 weeks after the surgery, and the newly generated tissue growing into the bone tunnel and fibroblasts were observed at 4 weeks. Till week 8, Sharpey's fibers were found in the interface with the formation of indirect insertion. In the rhBMP-2 group, the tendon-bone interface was filled with cartilage tissue at 2 weeks, and the four-layer direct insertion was formed at 4 weeks; till week 8, the interface was mainly composed of the direct insertion.</p><p><b>CONCLUSION</b>rhBMP-2 can induce direct insertion formation in the tendon-bone interface after early anterior cruciate ligament reconstruction. The direct insertion possesses better biomechanical properties than indirect insertion.</p>

Biomechanical reconstruction of the hip in metal-on-metal total hip resurfacing / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the effect of biomechanical reconstruction of the hip in metal-on-metal total hip resurfacing.</p><p><b>METHODS</b>Thirty patients undergoing hip resurfacing arthroplasties were enrolled in this study. The clinical outcomes of the patients were assessed according to the Harris Hip Score before and after the surgery, X-ray examinations and biomechanical reconstruction evaluations.</p><p><b>RESULTS</b>After the operation, the length of the patients' legs was shortened by a mean of 2.4 mm. and the femoral offset was decreased by a mean of 5.45 mm. No dislocation were be found in these patients. The preoperative Harris Hip Score was 36.69-/+7.16, significantly lower than that postoperative score (89.63-/+3.36, P<0.01).</p><p><b>CONCLUSION</b>Precise biomechanical reconstruction of the hip can be achieved in hip resurfacing arthroplasty, and the stability and functional restoration is guaranteed by large diameter prosthesis design.</p>

An experimental study on blocking paw withdrawal reflex by cutting magnetic curve with lumbar spine of rats / 中华神经医学杂志

Objective To observe nerve conduction blocking effects of magnetic curve cutting. Methods Twenty-four male SD rats were randomly assigned to 2 groups: experiment group and control group. In the former, rats were anesthetized and hung over a alum plate in which 20 pieces of magnet were embedded. The alum plate was rotated so as to the lumbar spine of the rat could cut magnetic curve passively at a speed of 60 m/s. The control group received the same treatment except that the magnets had no magnetism. The right paw of rat was clamped with a 100 g force for 1 s, and the withdrawal reflex was observed. Results During magnetic curves cutting, the paw withdrawal reflex disappeared in 91.67% rats of experimental group, whereas it existed in all rats of control group. The difference was statistically significan (P＜0.05). Withdrawal reflex was recovered in 83.33% of rats in experimental group as soon as the cutting stopped, and the control group still remained the reflex; there was no significant difference between the 2 groups (P＞0.05). The rats whose reflex failed to recover at first in experimental group, rcovered 5 minutes later. Conclusions When the lumbar spine of a rat cuts magnetic curve passively, the hindlimb withdrawal reflex will be blocked.

Surgery simulation with a percutaneous and transpedical interbody bone grafting apparatus / 南方医科大学学报

<p><b>OBJECTIVE</b>To develop a percutaneous and transpedical interbody bone grafting apparatus for vertebral bone defect reconstruction in thoracolumbar fracture correction via minimally invasive operation.</p><p><b>METHODS</b>The percutaneous and transpedical interbody bone grafting apparatus was designed with CAD software, and the reduction effect, range of bone grafting and surgical complications of the apparatus were investigated in adult cadaveric thoracolumbar body and with computerized surgical simulation.</p><p><b>RESULTS</b>The self-designed apparatus was convenient for percutaneous and transpedical interbody bone grafting that did not give rise to complications. CT showed large bone grafting area with increased density in the vertebral body corrected with this apparatus.</p><p><b>CONCLUSION</b>The designed apparatus allows easy manipulation and efficient bone grafting and repositioning. Minimally invasive interbody bone grafting in thoracolumbar fracture can be easily performed with proper application of the apparatus.</p>

A digital model for lumbar motion segment reconstruction and three-dimensional visualization / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish a digital model for reconstruction and three-dimensional visualization of lumbar motion segment from CT images.</p><p><b>METHODS</b>Based on 64 row spiral CT continuous 2-dimensional images of L4-L5 segments, the lumbar structure and various soft tissues were reconstructed with the Mimics software, followed by validation of this model using finite element analysis software.</p><p><b>RESULTS</b>The established three-dimensional digital model of lumbar motion segment included two vertebral bodies, cortical bone, cancellous bone, endplate, annulus fibrosus, nucleus pulposus and 6 types of ligaments. The output result of the digital model can be used to for research of computer aided design, rapid rototyping and finite element analysis.</p><p><b>CONCLUSION</b>The application of thin-layer CT and Dicom standard ensures more accurate digital model establishment, and Mimics software allows more convenient reconstruction of the human skeleton and various soft tissues to facilitate further research.</p>

Acidic fibroblast growth factor for preventing motor endplate degeneration and muscular atrophy after motor nerve injury: a morphological and electrophysiological study / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore measures to prevent motor endplate degeneration and muscular atrophy after motor nerve injury.</p><p><b>METHODS</b>Thirty Sprague-Dawley rats were randomized into 3 equal groups. In two of the groups, the right common peroneal nerves of the rats were transected and immediately sutured with implantation of collagen gel carrier of acidic fibroblast growth factor (aFGF) or the empty carrier into the denervated tibialis anterior muscles. In the control group, the transected nerves were sutured without implantation. Six weeks after the operation, morphological and electrophysiological examinations were performed.</p><p><b>RESULTS</b>In the control rats and those with empty collagen gel carrier implantation, obvious motor endplate degeneration and muscular atrophy occurred, which were not obvious in rats receiving aFGF carrier implantation. The decrement of repetitive nerve stimulation was significantly greater in the former two groups than in the latter.</p><p><b>CONCLUSION</b>Implantation of collagen gel carrier of aFGF may prevent motor endplate degeneration and facilitate functional recovery of the neuromuscular junction after motor nerve injury.</p>

Development of an anti-infection nano-hydroxypatite drug delivery microsphere and its drug-release in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To develop an anti-infection nano-hydroxypatite (nano-HA) microsphere for local drug delivery for treating osteomyelitis.</p><p><b>METHODS</b>The nano-HA was used as the core carrier to load gentamicin (GM) and coated with poly(-hydroxybutyrate-co- hydroxyvalerate)/polyethylene glycol (PHBV/PEG), which was degradable and biocompatible, to prepare nano-HA-PHBV/PEG-GM microsphere. The surface structure and in vitro drug-release of the microsphere were studied.</p><p><b>RESULTS</b>The microsphere had good drug delivery capability. The samples weighing 90 mg each were soaked in PBS and gentamicin release within the first day was 165.2 microg/ml, which maintained a low release rate in the following days. After 28 days, gentamicin release declined to 8.5 microg/ml, which was higher than the minimal inhibitory concentration of gentamicin (2 microg/ml).</p><p><b>CONCLUSION</b>The local drug delivery system has good drug-release performance in vitro and may possess potential value in clinical management of osteomyelitis.</p>

Finite element analysis of a new shape memory alloy cervical hook for atlantoaxial instability / 南方医科大学学报

The mechanics of a new shape memory alloy cervical hook for atlantoaxial instability was analyzed with finite element method on the basis of a three-dimensional model reconstructed from the images of CT scanning of an adult cadaveric upper cervical at 1-mm interval. The stress and displacement of every nodule and element in the course of deformation of the internal fixation were tested, and the results showed that the cervical hook was strong enough against tensile stress, which concentrates in the middle of the device. The pull was 237.58 N at the loading point. With such mechanical performance, this cervical hook can be reliable for correction of atlantoaxial instability.