Development and clinical application of a new transverse process retractor based on computer-aided design and 3D printing technology / 中国骨伤

OBJECTIVE@#To manufacture a new type of transverse process retractor by using computer-aided design(CAD) combined with 3D printing technology and investigate its clinical application effect.@*METHODS@#A new type of transverse protrusion retractor was developed by CAD combined with 3D printing technology. From September 2018 to September 2019, the new transverse process retractor was applied in clinic. Sixty patients with lumbar single segment lesions who needed treatment by pedicle screw fixation, bone grafting and interbody fusion were divided into new transverse process retractor group and control group, with 30 cases in each group. There were 14 males and 16 females in new type transverse process retractor group, the age was (68.0±4.3) years old on average; lesion segment of 8 cases were L3,4, 9 cases were L4,5, 13 cases were L5S1;5 cases of lumbar disc herniation, 20 cases of lumbar spinal stenosis, 5 cases of degenerative lumbar spondylolisthesis;new transverse process retractor was used to pedicle screw placement. While there were 15 males and 15 females in control group, with an average age of (69.2±4.5) years old;lesion segment of 8 cases were L3,4, 10 cases were L4,5, 12 cases were L5S1;5 cases of lumbar disc herniation, 21 cases of lumbar spinal stenosis, 4 cases of degenerative lumbar spondylolisthesis;the traditional lamina retractor was used for soft tissue pulling and finished pedicle screw placement by freehand. The length of surgical incision, the time required for inserting a single screw, fluoroscopy times, the times of adjusting the positioning needle or screw in insertion process, and the visual analogue scale (VAS) of surgical incision 72 hours after operation were compared between two groups.@*RESULTS@#Using CAD and 3D printing technology, a new type of transverse protrusion retractor was developed quickly. The length of surgical incision, the time required for inserting a single screw, fluoroscopy time, and the times of adjusting the positioning needle or screw in insertion process in new transverse process retractor group were less than those in control group(P<0.05). There was no significant difference in VAS of lumbar incision pain at 72 hours after operation between two groups(P>0.05).@*CONCLUSION@#Using CAD combined with 3D printing technology to develop a new transverse protrusion retractor has the advantages of convenient design, short development cycle and low cost. It provides a new idea for the research and development of new medical devices. The new transverse process retractor has the advantages of easy operation, reliable fixation, less damage to paravertebral muscle, convenient pedicle screw placement, reducing fluoroscopy time and so on.

3D printing technology assisted the preoperative planning and application value in adult kyphoscoliosis deformity / 中国骨伤

OBJECTIVE@#To explore the application value of 3D printing technology in preoperative surgery plan and intraoperative auxiliary operation for adult kyphoscoliosis deformity.@*METHODS@#The clinical data of 12 adult patients with kyphoscoliosis deformity treated from September 2017 to January 2019 were retrospectively analyzed. There were 3 males and 9 females, aged from 21 to 63 years old with an average of (47.67±13.32) years old. Among them, 4 cases were congenital kyphoscoliosis, 2 cases were old tuberculosis thoracolumbar kyphosis ; 2 cases were idiopathic kyphoscoliosis, 4 cases were degenerative kyphoscoliosis. The CT scan data of the patient's spine was imported into Mimics17.0 software to establish the three dimensional model of the spine, and the spine model was produced by 3D printer. Using the spine model simulated operation, preoperative surgery program planning and formulated a precise surgery, and further analysed postoperative imaging parameters improvement. All the patients were followed up for more than 1 year. Before and after operation and at the last follow-up, the scoliosis Cobb angle, maximum kyphosis Cobb angle, and coronal plane balance (distance between C 7 plumbline and center sacral vertical line, CPL-CSVL), sagittal plane balance (sagittal vertical axis, SVA), pelvic parameters and other related imaging parameters were measured to further evaluate its orthopedic effect.@*RESULTS@#Twelve patients with spine deformity were treated with different osteotomy and internal fixation fusion methods under the guidance of a 1∶1 spine model (pedicle screw placement of 4 patients with severe deformity were assisted by pedicle screw guide plates), nail placement and osteotomy have good effects, no major tissue damage such as blood vessels, nerves and spinal cord during and after surgery, no complications such as cerebrospinal fluid leakage and infection. Preoperative Cobb angle of scoliosis was (56.5±22.5) °, Cobb angle of kyphosis was (65.2±19.5) °, C PL-CSVL was (45.8±16.9) mm, SVA was (48.7±25.4) mm. Postoperative at 4 weeks, Cobb angle of scoliosis was (20.8±11.5) °, and Cobb angle of kyphosis was (22.0±6.6) °, with correction rates of (65.1±9.7)% and (64.6± 10.6)%, respectively ; C PL-CSVL was (22.3±8.9) mm, and SVA was (23.3±13.1) mm, all of which were significantly improved compared with preoperative results. The mean follow-up time was (18.5±7.9) months in 12 patients. At the last follow-up, the Cobb angles of scoliosis and kyphosis were (22.2±10.8) ° and (23.6±7.7) °, respectively, C PL-CSVL was (23.5±10.8) mm, and SVA was (24.7±12.5) mm. The results were statistically significant compared preoperative (0.05).@*CONCLUSION@#The 3D print model can visually and clearly show the vertebral morphology and structure of adult kyphoscolisis and its spatial relationship with the adjacent vertebrae, blood vessels, and nerves, which provides a good and intuitive stereoscopic anatomical structure observation for the individualization of the surgical plan. Pre-simulation of operations to determine the internal fixation, fusion segment and osteotomy orthopedic way, may to provide a reference for actual clinical surgery, and can improve the accuracy and safety of surgery.

Experimental study of individualized 3D printing-guided template combined with thoracolumbar pedicle screw placement for the treatment of ankylosing spondylitis / 中国骨伤

OBJECTIVE@#To evaluate accuracy and safety of individualized 3D printing guided template for thoracolumbar pedicle screw placement in patients with ankylosing spondylitis.@*METHODS@#From January 2016 to September 2019, thoracolumbar spine three-dimensional CT data of 8 patients with ankylosing spondylitis were included, Mimics 17.0 and ideaMaker computer software were applied to design thoracolumbar pedicle screw guided template of patients with AS, physical model of all patients (T-L)were printed by 3D printer, 2 parts in each patient, and divided into guide-plate-assisted screw group (experimental group) and free-hand nail group (control group). Thoracolumbar pedicle screws of both groups were placed by the same spinal surgeon. The accuracy of pedicle screw placement between two groups were evaluated according to results of postoperative CT, the accuracy of the fixation of thoracolumbar pedicle screw was divided into 4 grades, grade 0 and 1 screws were acceptable nails, grade 2 and 3 screws were unacceptable nails. The diameter and length of pedicle screws, the distance between entry point and posterior median line designed by preoperative 3D printing were compared with actual use in operation.@*RESULTS@#Twenty three blocks of thoracolumbar 3D printing screw of ankylosing spondylitis guided templates were designed and printed in guide-plate-assisted screw group, 46 screws were inserted and 44 screws were accepted. The time of implanting a screw into thoracolumbar pedicle was (4.20±1.15) min, the frequency of X-ray was (5.00±1.25) times and the average adjustment times of screw and Kirschner needle during screw placement was (1.76±1.32) times. In the control group, 46 nails were placed by traditional surgical method and 30 screws were accepted. The time of implanting a screw into thoracolumbar pedicle was (14.67±2.23) min, the frequency of X-ray fluoroscopy was (14.46±2.21) times and the average times of Kirschner needle adjustment was (4.76±3.39) times. The success rates between experimental group and control group were 95.65%(44 / 46) and 56.22%(30 / 46) respectively, and had statistical difference (χ=13.538, 0.05). The operation time of inserting a single screw, the times of X-ray fluoroscopy, and the average times of adjustment screw and Kirschner needle in experimental group were significant less than those in control group(<0.01).@*CONCLUSION@#The personalized guide template assisted the thoracolumbar fixation designed by 3D printing could significantly improve safety, accuracy and efficiency of surgery, especially suitable for thoracolumbar vertebral bodies requiring posterior pedicle screw fixation for fracture or dislocation with AS.

Determination of painful vertebrae treated by kyphoplasty in multiple-level vertebral compression fractures / 中华外科杂志

<p><b>OBJECTIVE</b>To explore how to determine painful vertebrae treated by kyphoplasty in multiple-level osteoporotic vertebral compression fractures and clinical outcome.</p><p><b>METHODS</b>From October 2002 to June 2005, 51 consecutive procedures with kyphoplasty were performed on 35 patients with multiple-level osteoporotic vertebral compression fractures. There were 51 painful vertebrae among 120 vertebral compression fractures. The painful vertebra was determined by the signal intensity changes in MR images, combined with radiography and local percussion pain before operation. Only painful vertebrae were treated by kyphoplasty. Preoperative, postoperative and final follow-up visual analog scale (VAS) and radiographic findings such as vertebral height and Cobb angle were recorded and analyzed.</p><p><b>RESULTS</b>All patients tolerated the procedure well with immediate relief of their back pain after kyphoplasty and they can walk at 1-3 days after the procedure. There were 3 vertebrae (3/51) occurred asymptomatic extravasation of cement. 31 cases were followed up for mean 16.2 months (range 6-44 months). VAS reduced from preoperative 8.7 to final follow-up 2.1 (P <0. 01). At final follow-up the vertebral height had a recovery rate of 59.17%, and the mean Cobb angle was improved 10.1 degrees. There was a significant improvement between preoperative and final follow-up values (P < 0.01).</p><p><b>CONCLUSIONS</b>The painful vertebra can be determined by signal intensity changes in MR series images in multiple-level osteoporotic vertebral compression fractures. Selecting painful vertebrae to be treated by kyphoplasty can make patients with multiple-level VCFs gain an excellent result.</p>

The relationship between lumbosacral transitional vertebra and the lumbar disc herniation / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the relationship between lumbosacral transitional vertebra and the lumbar disc herniation (LDH).</p><p><b>METHODS</b>The X-ray photographs of lumbar vertebra were retrospectively studied of patients with and without LDH confirmed by surgery, furthermore, the differential incidence of LDH between the two groups and the relationship between transitional vertebra and the position of disc herniation were statistically analyzed.</p><p><b>RESULTS</b>The incidence of lumbosacral transitional vertebra was 18.3% in the control group, 52.7% in the LDH group, the difference was statistically significant. In the group with single lumbosacral transitional vertebra, there was 75.9% of LDH occurred on the same side of the transitional vertebra, 81.8% of which occurred at the upper one disc of the transitional vertebra; whereas 17.2% of LDH on the opposite side of the transitional vertebra, 80.0% of which occurred at the lower one disc of the transitional vertebra.</p><p><b>CONCLUSIONS</b>There is a closer relationship between lumbosacral transitional vertebra and the LDH, and the lumbosacral transitional vertebra is one of the important factors in the emergence of LDH.</p>

Selectivity and individualization of transpedicular balloon kyphoplasty for aged osteoporotic spinal fractures / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the selectivity and individualization of transpedicular balloon kyphoplasty for aged osteoporotic spinal fracture.</p><p><b>METHODS</b>Twenty-two consecutive procedures were performed in 17 aged patients with osteoporotic spinal compression fractures from April 2002 to June 2004. The signal changes in different sequences were confirmed by magnetic resonance imaging before the procedures. This operation involved the percutaneous insertion of two inflatable bone tamps into a fractured vertebral body transpedicularly under fluoroscopic guidance. Every patient was treated individually, according to the results of radiography and CT scan before operation. Preoperative and postoperative complications, visual analogue scale, and radiographic findings such as vertebral height and Cobb angle were recorded and analyzed.</p><p><b>RESULTS</b>All patients tolerated the procedure well with immediate relief of their back pain in 24 hours. There was no leakage of cement into the epidura. The mean loss percent of the anterior and middle vertebral heights were (35.32 +/- 13.15)% and (27.53 +/- 12.61)% before operation, and (14.21 +/- 12.43)% and (16.2 +/- 7.5)% after operation. The height restoration of vertebra was confirmed by X-ray after the procedure (P < 0.01). The mean kyphosis was improved from (25.3 +/- 4.2) degrees to (8.6 +/- 5.1) degrees. No complications occurred. No patient had nerve injury. The patients were allowed to walk next day after the procedure.</p><p><b>CONCLUSION</b>The selectivity and individualization of transpedicular balloon kyphoplasty for aged osteoporotic spinal fractures has satisfactory short-term clinical efficacy. It is also an effective way to prevent complications.</p>

The contrast study between single and double balloon bilateral dilatation of kyphoplasty / 中华外科杂志

<p><b>OBJECTIVE</b>To contrast single and double balloon-inflated kyphoplasty for vertebral compression fractures (VCFs) and evaluate its clinical efficacy.</p><p><b>METHODS</b>From May 2000 to May 2004, 90 consecutive procedures were performed in 58 patients who suffered from painful vertebral compression fractures, transferring tumour and angioma. Ninety vertebrae were inflated while 62 as A group were double balloon and 28 as B group were single balloon, fracture reduction and bone cement augmentation. Preoperative and postoperative symptom levels, variables, complications were recorded and the vertebral height and Cobb angle were measured and analyzed.</p><p><b>RESULTS</b>All patients' pain was alleviated or disappeared without syndrome, and the vertebral height and Cobb angle of both groups were improved. The average recovery rate was 72.6% (22.9% approximately 100%), Cobb angle from 17.9 degrees (3.1 degrees approximately 31.6 degrees ) were corrected to 9.6 degrees (0.6 degrees approximately 28.2 degrees ), the average angle was 8.7 degrees (0.3 degrees approximately 27.2 degrees ), and the contrast between preoperative and postoperative showed obvious differences (P <0.001). The average recovery rate of A group was 77.6% (55.3% approximately 100%), B group was 64.3% (22.9% approximately 100%). The average postoperative Cobb angle of A group was 9.9 degrees (0.3 degrees approximately 27.2 degrees ), B group was 8.6 degrees (0.6 degrees approximately 19.8 degrees ) (P >0.05).</p><p><b>CONCLUSIONS</b>As a promising minimally invasive surgery, balloon kyphoplasty can provide early relief of pain and improve the function as well as spinal alignment in treatment of painful compression fracture owing to recovering the vertebral height and Cobb angle of the vertebral body. Single balloon-inflated kyphoplasty can improve VCFs as double balloon.</p>