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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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.

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>

Detection of gene expression pattern in the early stage after spinal cord injury by gene chip / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To study the changes of the gene expression pattern of spinal cord tissues in the early stage after injury by DNA microarray (gene chip).</p><p><b>METHODS</b>The contusion model of rat spinal cord was established according to Allen's falling strike method and the gene expression patterns of normal and injured spinal cord tissues were studied by gene chip.</p><p><b>RESULTS</b>The expression of 45 genes was significantly changed in the early stage after spinal cord injury, in which 22 genes up-regulated and 23 genes down-regulated.</p><p><b>CONCLUSIONS</b>The expression of some genes changes significantly in the early stage after spinal cord injury, which indicates the complexity of secondary spinal cord injury.</p>

Spontaneous spinal epidural hematom aand spontaneous spinal subdural hematoma:report of six cases / 中华骨科杂志

Objective To study the etiology,clinical presentation,MR images,treatment and prog-nosis of spontaneous spinal epidural and subdural hematoma.Methods From1995to2002,6cases diag-nosed as spontaneous spinal epidural and subdural hematoma were reviewed retrospectively.All of the pa-tients were males aging from30to68years with an average of 47years.The onset was acute while the pa-tients were in resting or light activity without prior history of any infection,administration of drugs or trau-ma.One patient had the history of hypertension,and another one was found to have diabetes after admission.The clinical characteristics were sudden pain involving neck,shoulder,chest and back,then dysfunction of motion and sensation of extremities and sphincter within few minutes.4cases of spontaneous spinal epidural hematoma were located at T 5~6 ,T 2~4 ,C 4~5 and C 6 ~T 1 respectively,and2cases of spontaneous spinal subdu ral hematoma at C 7 ~T 1 and C 7 ~T 2 respectively.Results All cases were proved with surgery and pathology.MR imaging showed occupying mass in the posterior or posteriolateral region inside the spinal canal.T 1 -weighted imaging was most useful owing to its typical signal changes with the hematoma.T 2 -weighted gra-dient echo sequence was capable to identify epidural and subdural spinal hematoma.Total laminectomy and hematoma debridement were performed.The outcome was closely related to the interval between the onset and surgery.The patients were followed up from6to18months with an average of 10months.All cases showed no significant improvement of spinal cord function except 5cases with incomplete recovery of sphincter function.Conclusion Spontaneous spinal epidural and subdural hematoma are rare entities.MRI is a most helpful diagnostic tool for this disorder.It should be stressed that early diagnosis and prompt surgical intervention are of great importance for prognosis of spontaneous spinal epidural hematoma.