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BACKGROUND: 3D printed bone model was widely used in clinical teaching and simulated surgery training, but it did not pay enough attention to the construction of soft tissue, and the simulation was poor, which cannot reflect the soft tissue exposure process. OBJECTIVE: To explore the feasibility of constructing a simulated lumbar spine surgery model based on 3D printing technology for the training of lumbar pedicle screw placement in junior orthopedic surgeons. METHODS: The solid model of the lumbar spine was printed at the same proportion based on 3D printing technology, and the model of simulated lumbar spine surgery was constructed with plasticine and cloth. Thirty orthopedic residents performed lumbar pedicle screw placement alone on the simulated model, and performed once a day for 10 consecutive days. They recorded the operation time, and evaluated the accuracy of screw placement by postoperative CT scan. By comparing the operation time and screw placement accuracy of the operators in the early stage (the first 5 times) and the later stage (the last 5 times), all above parameters were statistically analyzed. This study was approved by the Ethics Committee of Zigong Fourth People's Hospital. RESULTS AND CONCLUSION: (1) In the early stage (the first 5 times), the average operation time was (100. 00+12. 67) minutes. In the later stage (the last 5 times), the average operation time was (83. 50+10. 14) minutes, and the difference was statistically significant (f=20. 67, P=0. 00). (2) The success rate of former screw placement (including grade I and II screw placement) was 88. 53%, and the failure rate (grade III screw placement) was 11. 47%. The success rate and failure rate of latter screw placement were 97. 47% and 2. 53%, respectively, with statistically significant difference (x2-20. 68, P=0. 00). (3) The simulated model of lumbar spine surgery based on 3D printing technology has high simulation and feasibility, and can be used for the training of lumbar pedicle screw placement in junior orthopedic surgeons.
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Objectives To evaluate the 3D printed navigation template used to assist axis pedicle lag-screw placement in the treatment of atypical Hangman's fracture(AHF).Methods From May 2015 to January 2017,12 patients with AHF were treated at Department of Orthopedics,The Fourth Peopled Hospital of Zigong.In their operation,the axis pedicle lag-screw placement was assisted by a 3D printed navigation template.They were 8 men and 4 women,aged from 27 to 53 years(average,45.6 years).There were 7 cases of type Ⅰ,4 cases type Ⅱ and one case of type HA according to the Levine-Edwards classification.There were 2 cases of grade D and 12 cases of grade E according to the assessment of America Spinal Injury Association(ASIA).Their preoperative and postoperative neck pain was evaluated by visual analogue scale(VAS);their preoperative and postoperative ranges of cervical motion were recorded and compared.To evaluate the postoperative safety of screws,the insertion point,position within the pedicle,axial angle and sagittal angle of the screws and maximum fracture displacement were compared between actual operation and simulative operation.Results A total of 12 guide plates were designed and printed;a total of 24 lag-screws were placed.All patients underwent surgery uneventfully.They were followed up for 12 to 20 months,with an average of 14.7 months.Two patients with ASIA grade D recovered to ASIA grade E at the last follow-up.All patients showed a significant improvement in neck pain.Their VAS score at 5 days after surgery(5.86±2.02) was significantly lower than their preoperative score(8.29±1.88)(P<0.05) and their VAS score at the last follow-up(1.73±0.87) was also significantly lower than that at 5 days after surgery(P<0.05).Their range of cervical motion at 6 months after surgery was significantly larger than that at 3 months after surgery(P<0.05);their range of cervical motion returned to normal roughly at the last follow-up,showing no significant difference from that at 6 months(P>0.05).Their postoperative X-ray and CT images showed that the dislocation was all corrected.The last follow-up showed no obvious vertebral instability,screw breakage or loosening.Postoperative CT showed that the 24 screws had been located completely in the pedicle(grade 0),indicating that the screw placement was 100% accurate.The postoperative deviation at insertion point(0.70±0.78 mm),deviation within the pedicle(1.3±0.82 mm),axial angle(8.26°±0.88°) and sagittal angle(22.62°±0.86°) of the screws showed no significant differences from the preoperative simulative data(P>0.05).There was a significant difference in the maximum fracture displacement between the preoperative data(3.94±0.38 mm) and the postoperative data(2.21±0.39 mm)(P<0.05).Conclusion The 3D printed navigation template can be used to better assist axis pedicle lag-screw placement in the treatment of AHF,because it ensures safe screw placement,leading to good reduction and fixation and precise match with the preoperative plan.
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BACKGROUND: It has been found that the distribution and diffusion degree of bone cement are the main factors influencing the clinical effect of percutaneous vertebroplasty. OBJECTIVE: To explore the feasibility of analyzing bone cement distribution form and diffusion degree based on Mimics software, and to evaluate the relationship of clinical efficacy with bone cement distribution form and diffusion degree. METHODS: A total of 170 cases of osteoporotic vertebral compression fracture admitted to Zigong No. 4 People's Hospital from January 2017 to March 2018 were included, including 41 cases of males and 129 cases of females aged 60-97 years. All of them were treated with percutaneous vertebroplasty. X-ray and CT examination were done at postoperative 2 days, and the bone cement distribution was classified into five types based on the distribution of bone cement in X-ray images, including type Ⅰ (most cement continuously and evenly distributed in the vertebral body), type Ⅱ (most cement distributed in the central vertebral bodies), type Ⅲ (most cement distributed on both sides of vertebral body), type Ⅳ (most cement distribution at the side of the vertebral bodies and the central), type Ⅴ (most cement distribution at the side of the vertebral body). Mimics project files were created based on CT image data to calculate bone cement volume and diffusion volume. After 6 months of follow-up, visual analogue scale score, Oswestry disability index and Cobb angle were compared among groups to analyze the relationship between bone cement distribution, bone cement diffusion volume, bone cement diffusion volume ratio and clinical efficacy. RESULTS AND CONCLUSION: (1) The visual analogue scale score and Oswestry disability index of the five types of bone cements were significantly improved at 2 days and 6 months after surgery compared with preoperative data (P < 0.05), the Cobb angle of the type Ⅰ group was significantly improved compared with preoperative data (P < 0.05), and the Cobb angles of the type Ⅱ-Ⅴ groups showed no difference from the preoperative data (P> 0.05). (2) The diffusion volume of bone cement was (6.69±1.19) mL, and the diffusion volume ratio of bone cement was (20.93±3.13) ％. There was no correlation between the volume of bone cement injection and the visual analogue scale score, Oswestry disability index and Cobb angle at 2 days and 6 months after surgery. There was a negative correlation between the bone cement dispersion volume and the visual analogue scale score at 6 months after surgery, and the Oswestry disability index score at 2 days and 6 months after surgery (P < 0.05), but the correlation was weak. The diffusion volume ratio of bone cement was negatively correlated with the visual analogue scale score and Oswestry disability index score at 2 days and 6 months after surgery (P < 0.05), showing a strong correlation. These findings show that, based on the three-dimensional reconstruction function of Mimics software, the diffusion volume and diffusion volume ratio of bone cement can be accurately calculated. The bone cement evenly distributed can alleviate the local kyphosis. The diffusion volume ratio of bone cement is positively correlated with clinical efficacy, which is more valuable than the volume of bone cement.
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Objective To explore the clinical efficacy of 3D printing technique in assisting sacroiliac screwing in combination with front ring nail-rod system for treatment of unstable pelvic fractures.Methods From July 2015 to June 2017,3D printing technique was used to assist the sacroiliac screwing in combination with front ring nail-rod system for 16 patients with unstable pelvic fracture at Orthopaedic Center,The Fourth People's Hospital of Zigong.They were 9 males and 7 females,aged from 19 to 60 years (average,39.8 years).By the Tile classification,5 cases were type B1,6 type B2,3 type B3 and 2 type C.Their operation duration,bleeding,fluoroscopy frequency,incision length,postoperative fracture reduction,success rate of sacroiliac screwing,accuracy of sacroiliac screwing,perioperative complications,weight-bearing exercise time,fracture healing time and the Majeed scores at the last follow-up were documented.Results All the 3D models and navigation templates were successfully designed and printed.Surgery succeeded in all the patients.Follow-ups ranged from 6 to 18 months,averaging 13.3 months.The bleeding ranged from 100 to 250 mL,averaging 162.4 mL;the operation duration ranged from 60 to 120 min,averaging 73.2 min;the intra-operative fluoroscopy frequency ranged from 13 to 31 times,averaging 17.4 times;the incision length ranged from 16 to 32 cm,averaging 21.1 cm.All the incisions healed by the first intention and all the fractures obtained osseous union after 90 to 120 d (average,102.3 d).No significant complications like neurovascular injury or pulmonary embolism happened.The weight-bearing exercise time ranged from 25 to 40 d,averaging 31.5 d.According to the Matta imaging scores,the reduction was rated as excellent in 12 cases and good in 4.Altogether 28 screws were inserted with a success rate of 100％.Compared with the preoperative simulated screwing,the actual screwing angle deviated postoperatively by 0.12° ± 0.32°,the X axis by 0.36 ± 1.24 mm,the Y axis by 0.36 ± 1.24 mm and the Z axis by 0.22 ± 1.26 mm,showing no statistically significant difference between the actual 3D deviations and the test value of 0 (P ＞ 0.05).Conclusion In the treatment of unstable pelvic fractures,3D printing technique can be used in preoperative preparation of the connecting rod in the front ring nail-rod system to assist the sacroiliac screwing,significantly shortening the operation duration,reducing bleeding,ensuring safe and accurate screwing,and facilitating functional recovery.
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Objective To construct a novel tissue?engineered bone matrix gelatin (BMG)/poly[butylene succinate?co?tere?phthalate] (PBST) biphasic scaffold for annulus fibrosus. Methods The PBST spinning fibers were prepared by electrospinning and the porosity and water absorption rate were tested. Rabbit annulus fibrosus cells were isolated, cultured and identified through SafraninOstaining, and collagenⅡimmunohistochemical staining in vitro. And then annulus fibrosus cells were implanted on the PBST fiber, whose growth situation was observed by scanning electron microscope (SEM). Then the BMG/PBST biphasic scaf?fold was constructed by BMG as the outer annular fibrosus and PBST fiber as the inner annular fibrosus. The annulus fibrosus cells were implanted on the biphasic scafflod and cultured for 3, 7 and 21 days in vitro. The biomechanical and biological property was observed at the predetermined time point. Results The porosity of the fiber was 61.83%±7.33%and its water absorption rate was 297.34%± 57.13%. The identified result of annulus fibrosus cells were positive, suggesting that the cells have still kept their annulus fibrosus cells characteristics. The cells growth could be observed through SEM at 3rd and 7th day after implanted on the fi?bers. After cultured on the BMG/PBST scaffold, HE staining proved that the cells could ingress into the inner of fiber with time. SafraninOstaining and collagenⅡimmunohistochemical staining proved that the cells can secreted abundant proteoglycan and collagenⅡ, the special annulus fibrosus cell extracellular matrix. Compared with the BMG/PBST scaffold without cells, the elastic modulus of biphasic scaffold was increased from 14.83±1.02 MPa to 17.56±1.47 MPa after cultured with cells for 21 days in vitro. Conclusion The novel tissue?engineered biphasic scaffold for annulus fibrosus constructed with BMG and PBST fiber spinning has good cytocompatibility and biomechanical characteristics, which provide a basis for the complete tissue engineered interverte?bral disc.
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Objective To fabricate a novel tissue-engineered cartilage with adipose-derived stem cells (ADSCs) seeded on the chitosan hydrogel scaffold to repair articular cartilage defect.Methods Adipose tissue and costal cartilage were harvested from New Zealand rabbits,and ADSCs in passage one and chondrocytes were obtained after the samples were digested and cultured in vitro.ADSCs were digested,suspended,seeded onto the sterile chitosan gel,and cultured in vitro for 1 week to fabricate the tissue-engineered cartilage.The defects were respectively filled with the tissue-engineered cartilage (composite group),chondrocyte suspension (cell group),chitosan gel (material group) and nothing at all (control group).At postoperative 12 weeks,cartilage repair was evaluated using the gross examination,histological staining,immunohistochemical staining and international cartilage repair society (ICRS) histological score.Results Effect of cartilage repair in composite group was significantly better compared to other groups.The regenerated tissue in composite group seemed tightly bound in normal tissue,with similar structure and extracellular matrix secretion.ICRS histological score in composite group was (13.89 ± 0.14) points,which differed significantly from (7.06 ± 0.19) points in control group,(7.14 ± 0.22) points in cell group and (7.46 ± 0.26) points in material group (P ＜0.01).Conclusion The tissue-engineered cartilage with ADSCs seeded onto the chitosan hydrogel is effective for repair of articular cartilage defect.
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BACKGROUND:Tissue-engineered intervertebral disc has provided a new biological therapeutic approach for intervertebral disc degeneration. Tissue-engineered annulus fibrosus is one key step of constructing a complete tissue-engineered intervertebral disc. OBJECTIVE:To sum up the research progress of tissue-engineered annulus fibrosus from the folowing aspects: structural features, scaffold materials, seed cels. METHODS:PubMed database and Wanfang database (2000-2015) were retrieved by the key words of “tissue engineering, intervertebral disc, annulus fibrosus, seed cel, scaffold, construction” in Chinese and in English, respectively. According to inclusion and exclusion criteria, 48 literatures were involved for summarization. RESULTS AND CONCLUSION: Previous studies about tissue-engineered annulus fibrosus only focused on cel adhesion, proliferation and extracelular matrix secretion on the scaffold. Currently, tissue-engineered annulus fibrosus exhibit similar features to the natural annulus fibrosus in the folowing aspects: cel function, tissue structure and mechanical features, and relevant animal experiments have achieved certain results in animal experiments. However, it is stil difficult to build a tissue-engineered annulus fibrosus entirely similar to the natural one, and we need to further improve scaffold materials, culture conditions, colection of seed cels. The current strategies of annulus fibrosus construction stil focus on single phase of scaffold, and the biphasic scaffold and complete intervertebral disc scaffold wil be the trend of the researches. Technology of induced differentiation of stem cels provides a broach source of seed cels for tissue-engineered annulus fibrosus.
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Objective To investigate the best digestion time for rabbit rib cartilage cells separation by collagenase Ⅱ diges‐tion method .Methods Rabbit cartilage tissue was taken from 3‐month‐old New Zealand white rabbits ,and then digested in 0 .2%collagenase Ⅱ solution for 4 ,8 ,12 ,16 and 20 h under vibration at 37 ℃ ,respectively .The corresponding experiments were named as group A ,B ,C ,D ,and E .The obtained primary cells were cultured and passaged after counting .The cell morphology ,proliferation rate ,secretion of extracellular matrix of passage 2 cells were compared to chose the best digestion time .Results The primary chon‐drocytes obtained in group C ,D and E were more than the other two group A and B .The chondrocytes cytoactive in group C and D were better than the other three group A ,B and E .The passage 2 chondrocytes in group C ,D had better secretion of extracellular matrix capability than the other three groups .Conclusion The best collagenase Ⅱ digestion time is 12 to 16 h ,at this digestion time period ,more primary chondrocytes with high cytoactive and strong proliferation capability can be obtained ,and the phenotype of their passage 2 cells is quite good .