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Objective To construct a new biomechanical testing system of in vitro spine based on LabVIEW and six-axis robot arm and conduct preliminary reliability studies, so as to make preparation for further studies on coupled motion testing. Methods By programming on LabVIEW platform, using Ethernet and Profibus to communicate the data of the robot arm with PC in real time, the displacement control and load control were realized, and the end position and rotation angle of the robot arm were read in real time. Through the force/torque sensor and data acquisition (DAQ), board DAQ, processing, storage and other functions were acquired. Using the digital micrometer and special stationary fixture, the 6-direction translation accuracy test was completed, and the data were analyzed. The flexion, extension, lateral flexion and rotation were applied on sheep spine specimen to draw the load-displacement curve, analyze and compare the experimental result, and verify the effectiveness of the biomechanical platform. Results A biomechanical test system with high precision for spine in vitro based on LabVIEW and 6-axis robot arm was developed and established, of which the average translational precision was 8.1 μm and the average translational accuracy was 56.7 μm. The program of control, data acquisition, data processing and storage were written, and the biomechanical test of the sheep spine was completed effectively. Conclusions This biomechanical test system based on Labview and 6-axis robot arm could complete the conventional three-dimensional spinal motion test with high precision and be used to conduct coupled motion test research in the next step.
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BACKGROUND: Minimally invasive percutaneous pedicle screw fixation possesses the advantages of less blood loss, less muscle and soft tissue dissection, and rapid recovery; however, accuracy of the screw positioning is the key to be successful.OBJECTIVE: To explore the application value of self-designed spinal localizer in the screw positioning for minimally invasive percutaneous pedicle screw fixation.METHODS: 428 patients with thoracolumber disorders were subjected to minimally invasive percutaneous pedicle screw fixation at the First Affiliated Hospital of University of South China, from March 2009 to March 2015, and randomly underwent the preoperative screw positioning by self-designed spinal localizer or one of traditional localizing methods (iliac crest, ribs, symptomatic vertebral appearance, skin marker, Kirscher wire, puncture needle localizations). The location accuracy, positioning time and radiographic times were compared among methods.RESULTS AND CONCLUSION: (1) Compared with the traditional localization methods, the self-designed spinal localizer was superior in accurate rate (P < 0.05), cost less positioning time (P < 0.05) and received less radiation (P < 0.05). (2) To conclude, the self-designed localizer exhibits a certain application value, which is an ideal method in preoperative localization for minimally invasive percutaneous pedicle screw fixation.
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Objective To evaluate the feasibility and efficacy of atlantoaxial fusion by flipping periosteum pedicle occipital outer plate.Methods Between March 2010 and June 2013,27 patients with atlantoaxial instability were treated by atlantoaxial fusion with flipping periosteum pedicle occipital outer plate and combining pedicle screws fixation.There were 16 males and 11 females with the age ranging from 23 to 56 years (with an average of 45.6 years) at time of surgery.There were 12 cases of fresh odontoid fracture with atlantoaxial instability,7 cases of old odontoid fracture combined with uneducable atlantoaxial dislocation,7 cases of congenital loose of odontoid process,and 1 case of rheumatoid arthritis.The visual analog scale (VAS) scores and Frankel grades were respectively used to evaluate the axial neck pain and the neurological deficit,and the results were compared before and after the operation.Bony fusion was observed by the midline sagittal CT scan images.Results All the patients were successfully operated.The operation time was 90 to 140 mins (with an average of 100 mins),and the blood loss was 100 to 600 ml (with an average of 160 ml).All patients were followed up for 18 to 39 months,with an average of 32.6 months.19 cases got solid fusion 3 months after surgery,and 7 cases got solid fusion 6 months after surgery,while 1 case got solid fusion 9 months after surgery.The average VAS score at final follow-up was 2.87± 1.03,which was significantly lower than that preoperatively 7.23± 1.65.Before the operation,nine cases presented spinal nerve function damage.At the final follow up time,7 cases returned to complete normal and 2 cases improved from grade C to grade D according to the Frankel classification.1 case was complicated with veiniplex injury with no heavy blood loss,due to successful hemostasia.Two screws were placed close to the vertebral artery canal,without clinical consequences.Conclusion The flipping periosteum pedicle occipital outer plate as a bone graft is one effective method for atlantoaxial fusion,which got great feasibility and safety.
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[Objective]To evaluate the effects of clinical application of B-twin and cage for treatment of lumbar degenetative disease. [Methods]From June 2004 to December 2007,a total of 112 patients with lumbar degenetative disease who underwent posterior lumbar interbody fusion(PLIF) with cage and 79 patients who underwent PLIF with B-twin were enrolled. Sixty patients were selected and randomly divided into two groups(30 in each group). The clinical curative effect, the rate of bone graft fusion, the intervertebral space height and complications in both groups were analyzed and compared.[Results]In the B-twin group, the treatment was a minimally invasive technique, which offered a satisfactory effect with good bone graft fusion, fewer complications and sooner recovery, but the cost was higher than that in cage group. The cage treatment was an open sugery for fenestration operation. It had more complications but more sufficient decompression and lower cost. The rates of bone graft fusion between the 2 groups were not different in statistics.[Conclusion]The B-twin and cage techniques are two treatmens for interbody fusion of lumbar degenetative disease. Both have advantages and clinical application value. It should be choosen according to different specific conditions in the clinical practice.
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[Objective]To evaluate the clinical outcome of anterior correction of thoracolumbar scoliosis utilizing Kaneda anterior scoliosis system(KASS).[Method]There were 43 cases of thoracolumbar scoliosis treated by anterior disc excision,interbody fusion and correction with KASS,male 17 cases,female 26 cases,idiopathic scoliosis 35 cases,and congenital scoliosis 8 cases.[Result]All cases had satisfactory correction results and the corrections were well maintained at average 22 months follow-up.The Cobbs angle of preoperation and postoperation were 66?(43?～98?)and 18?(0?～32?),the corrective rate was 91.7%.No case had death or neurological paralysic symptom.[Conclusion]Anterior correction of thoracolumbar scoliosis utilizing KASS can achieve satisfactory results with less fusion levels and can maintain the correction.It is a valuable surgical procedure for the correction of thoracolumbar scoliosis.
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[Objective]To introduce cervical laminoplasty fixation with Ti-mesh plates in posterior open door decompression and evaluate its clinical outcomes.[Method]A total of 27 cases with cervical spinal stenosis were treated by laminoplasty with mini titanium plates.The mean following-up time were 18 months.[Result]All cases were primary healed,the preoperative symptoms were improved satisfactorily with 88% good to excellent outcome over 6 months following-up.One case without relief of nurological symptoms underwent an additional anterior multilevel corpectomy.The surgical lamina achieved bone fusion without stenosis.[Conclusion]The laminoplasty with Ti-mesh plates restore spinal posterior construction with less loss of range of motion and maintain larminar in open position without stenosis.The surgical procedure is easier to perform with less complication rates.