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Objective:To investigate the safety and efficacy of short-segment fixation covering the fractured vertebrae via posterior intermuscular approach plus percutaneous kyphoplasty (PKP) through the outer upper edge of the base of the fractured vertebral pedicle in the treatment of osteoporotic thoracolumbar burst fracture.Methods:A retrospective case series study was used to analyze the clinical data of 56 patients with osteoporotic thoracolumbar burst fracture admitted to Ningbo No.6 Hospital from January 2018 to February 2021, including 24 males and 32 females; aged 56-72 years [(63.5±4.6)years]. All patients underwent short-segment fixation covering the fractured vertebrae via posterior intermuscular approach combined with PKP through the outer upper edge of the base of the fractured vertebral pedicle. The operation time, intraoperative blood loss, hospitalization day and surgery-related complications were recorded. The visual analogue score (VAS) of back pain, ratios of the anterior, middle and posterior height of the fractured vertebrae and kyphotic Cobb angle were compared before operation, at postoperative 2 days and at the final follow-up.Results:All patients were followed up for 12-28 months [(14.5±2.2)months]. The operation time was 55-85 minutes [(62.0±12.1)minutes], intraoperative blood loss was 80-150 ml [(94.0±18.5)ml], and hospitalization day was 5-9 days [(7.4±1.1)days]. Based on CT examination at postoperative 2 days, there were 2 patients with paravertebral cement leakage, 2 with intervertebral space leakage and 1 with intracanal leakage, but none reported associated clinical symptoms. No implant failure or fractures of adjacent segments was detected during the follow-up period. The VAS was significantly decreased from preoperative (7.5±1.2)points to (3.2±0.8)points at postoperative 2 days ( P<0.01), and the score was further lowered to (2.2±0.8)points at the final follow-up when compared with that at postoperative 2 days ( P<0.01). The ratios of the anterior, middle and posterior height of the fractured vertebrae and kyphotic Cobb angle were significantly improved at postoperative 2 days [(89.5±13.2)%, (85.8±7.9)%, (89.5±9.0)% and (5.6±3.2)°] when compared with those before operation [(48.9±11.8)%, (61.9±11.9)%, (79.9±9.8)% and (26.3±5.6)°] (all P<0.01). Slight losses were observed in the ratios of the anterior, middle and posterior height of the fractured vertebrae and kyphotic Cobb angle at the final follow-up [(87.0±12.7)%, (82.1±7.8)%, (88.6±10.0)% and (5.4±3.2)°], but not significantly different from those at postoperative 2 days (all P>0.05). Conclusion:Short-segment fixation covering the fractured vertebrae via posterior intermuscular approach plus PKP through the outer upper edge of the base of the fractured vertebral pedicle can safely and effectively treat osteoporotic thoracolumbar burst fracture, for it can significantly improve back pain, restore the height of the fractured vertebrae and correct the kyphotic deformity.
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Objective To assess the effects of axial spinous process-muscle-vascellum complex transplantation for posterior atlantoarial fusion.Methods Data of 27 cases with altantoarial disease who were treated by posterior atlantoarial fusion using axial spinous process-muscle-vascellum complex transplantation from June 2015 to June 2016 were retrospectively analyzed.There were 19 males and 8 females aged from 9 to 68 years old (mean,41.0±15.4 years old).Two cases were diagnosed with atlanto-axial instability.Fourteen cases were diagnosed with atlas fracture and eleven cases were diagnosed atlanto-axial fracture.All the 27 patients suffered from neck pain or limitations of cervical motion.All patients were assessed clinically by atlantoaxial reduction and bone graft fusion.The pre-operative and post-operative atlanto-dens interval (ADI),visual analogue scale (VAS),Japanese Orthopaedic Association scores (JOA),improvement rate of JOA score and axial symptoms were measured and statistically analyzed.Complications were recorded.Clinical outcome of latest follow-up was evaluated by X-ray and CT scan.Results The time of operation was 2.0-2.5 h and blood loss was 150-300 ml.All the patients were followed-up for 9 to 18 months (mean,11.5±2.1 months).The VAS of neck pain improved from 3.6±2.7 (range,2.0-5.0) pre-operatively to 1.4±0.2 (range,0-2.0) 12 months postoperatively (P=0.000).The JOA score improved from 11.7± 1.9 (range,10.0-15.0) pre-operatively to 15.3±0.6 (range,14.0-17.0)12 months post-operatively (P=0.000).The improvement rate of JOA score at the latest follow-up was 54.1％± 12.4％,including 23 cases (85.19％) excellent,and 4 cases (14.81％) good.The results of axial symptoms were no-symptom in 22 cases (81.48％) and mild symptoms in 5 cases (18.52％).Postoperative cervical spine X-ray and CT showed that the sagittal cervical spine alignment was restored.There was statistically significant difference between ADI of 4.3±1.1 mm (range,3.9-4.5 mm) pre-operatively to 2.5± 0.4 mm (range,2.1-2.6 mm) 12 months post-operatively,which was improved significantly (P=0.000).There were no complications found during the follow-up.Conclusion The application of axial spinous process-muscle-vascellum complex transplantation for posterior atlantoaxial fixation can preserve the dynamic function of muscles and reduce the postoperative pain,as well as avoid donor site morbidity.
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Objective To explore the biomechanical properties of posterior occipital condyle screws compared with common occipitocervical fusion internal fixation and it's impacts upon stress of hypoglossal canals.Methods Finite element models based on the occipitocervical CT data of one 28-year-old male healthy volunteer were built,including normal model,instability model,internal fixation model by occipital condyle screws,internal fixation model by occipital plate screws,and internal fixation model by transarticular screws.Fifty N gravity and 1.5 N · m torque were exerted upon the surface of occipital bone so that the models could perform lateral bending,flexion,extension,and rotational motions.The motion range and stress distribution of internal fixation were compared under varying conditions among different occipitocervical fusion models.In addition,the impact of occipital condyle screw upon hypoglossal canals was examined.Results Compared with instability model,the motion range in the internal fixation model by occipital condyle screws declined by 96.8％,95.6％,95.0％ and 98.5％ respectively in lateral bending,flexion,extension and rotation.In the internal fixation by occipital plate screws,the motion range decreased by 96.3％,95.7％,98.4％ and 99.6％ respectively.In the internal fixation by transarticular screws,the motion range exhibited a decline of 95.7％,94.0％,94.3％ and 98.9％,respectively.The stress peaks in the occipital condyle screw were 192.4 MPa,201.6 MPa and 187.6 MPa under lateral bending,flexion,and rotation conditions,respectively.The stress peaks in the occipital plate screw were 279.6 MPa,213.7 MPa,and 154.1 MPa,respectively.The stress peaks in the transarticular screw were 232.4 MPa,220.9 MPa,and 224.5 MPa,respectively.The stress impact peak of occipital condyle screw on the hypoglossal canals wall was 12.96 MPa,and the content deformationunder the hypoglossal canal was 0.64％.Conclusions The occipital condyle screw internal fixation has similar stability with common occipitocervical fusion fixations.The occipital condyle screw has more uniform stress distribution and less effect on the hypoglossal canals,and hence is safe and reliable as anchor point on the cranial side in occipitocervical fusion.
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Objective To investigate the safety of the occipital condylar screw with vertical position and evaluate the selection strategy of the posterior approach of the posterior occipital condylar screw in Chinese people.Methods The clinical imaging data of 60 outpatients from September 2013 to September 2015 were retrospectively analyzed,36 male and 24 female,the average age was 41.6±9.2 (range from 25-58),Excluded occipitocervical injury,tumor and deformity patients.We built a three-dimensional digital model and simulated placing screw by utilizing CT data on Mimics software,after that we took the occipital condyle posterior medial and lateral midpoint as the entry point,then made 2 points equidistantly to the midpoint in vertical direction.We put 3.5 mm diameter virtual screws in 4 different conditions:largest cranial angle,smallest cranial angle,longest screw path and shortest screw path.Then we assessed the anatomical relationship between the screw and the hypoglossal canal or the atlanto-occipital joint by a three-dimensional window and measured the cranial angle,medial angle and length of screw path,then calculated the safety angle of the cranial angle,the successful rate of setting screw,and compared the safety of different screw points by 3-Matic software.Results 120 occipital condyles were obtained from the CT data of 60 patients by Mimics software.There was no significant difference in the data of the cranial angle,medial angle,safety range and length between both left and right sides.The obtained safe cranial angle of each point respectively was 20.9°±6.0° (lowest point),17.0°±6.2° (middle point),and 11.6°±7.1°(top point),obviously the largest angle was in the lower point and the smallest was in the top point.The difference was statistically significant.We then acquired the successful rates of different cranial angle of each point,the highest successful rate was 99.17％,96.67％,74.17％ in lowest,middle and top point when cranial angle were 3°or 4°,3°and 0°respectively.The successful rates of lower point and niddle point were significantly higher than the top point,and the difference was statistically significant.The medial angle parameters obtained were 34.41°±2.59°on left and 34.06°±2.44°on right,and there was no significant difference.The length parameters of the longest screw path acquired were 23.09± 1.47 mm,22.84± 1.40 mm and 23.15± 1.45 mm at top,middle and lowest entry point.The average value of shortest screw path of each point was 21 mm,and there was no significant difference among every entry point.Conclusion Among the occipital condyle posterior screw entering points,selecting the lower point can improve the success rate and safety;the change of nail enter point in the vertical direction has little effect on the length of the nail.We can increase the safety and reduce the risk of occipital condylar screw placement as far as possible through the three-dimensional digital technology.
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Objective To evaluate the clinical effect of postural reduction combined with miniincision screw-rod system and percutaneous kyphoplasty (PKP) in treating osteoporotic thoracolumbar burst fractures.Methods A retrospective case series study was performed for data of 35 patients with osteoporotic thoracolumbar burst fractures without neurological deficits undergone mini-incision screw-rod system fixation and PKP between January 2012 and January 2014.There were 14 males and 21 females,with a mean age of 63.2 years (range,50-72 years).Operation time,intraoperative blood loss,complications,visual analogue score (VAS),height of fractured vertebrae and kyphosis Cobb angle were recorded.Results Operation time was (49.6 ± 6.8) min,and intraoperative blood loss was (45.6 ±7.8)ml.All patients were followed up for 9-18 months (mean,13.5 months).No intraoperative or postoperative serious complications occurred,including intracanal cement leakage,breakage or loosening of the screws.VAS of back pain was decreased from (8.4 ± 1.1)points preoperatively to (3.5 ± 0.6)points postoperatively (P ＜ 0.05).Height of the fractured vertebrae was improved from (49.62％ ± 5.68)％ preoperatively to (86.64 ± 6.63) ％ postoperatively (P ＜ 0.05).Kyphosis Cobb angle was improved from (28.12 ± 1.06) °preoperatively to (5.15 ± 1.08) °postoperatively (P ＜0.05).At the final follow-up,VAS was further decrease and vertebral height and Cobb’ s showed a slight loss of correction.Conclusion Postural reduction combined with mini-incision screw-rod system and PKP can relieve back pain,restore the height of injured vertebrae,correct kyphotic deformity and reduce operation time and blood loss,indicating a minimally invasive,safe and effective procedure for treatment of osteoporotic thoracolumbar burst fractures.
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Hyaluronic acid (HA) is an important biomaterial as the extracellular matrix in human body. We produced HA by fermentation of Streptococcus iniae (Strep.). Production of HA by Strep. was evaluated and further improved by strain mutation by ultraviolet. One strain with higher HA yield and lower content of protein was obtained. Its HA yield increased from (82.3±3.3) mg/L to (120±10.6) mg/L, and protein decreased from (0.178±0.011) mg/L to (0.032±0.017) mg/L. The molecular weight (MW) of HA yield from Strep. is about 3.0×10⁵ Da. Using the method of freezing and thawing, HA aqueous solution was transferred into hydrogel. This HA hydrogel, casted on sterilized non-woven fabric, was applied to repair rabbit skin with full-thickness defect. The preliminary results of the animal tests displayed that HA hydrogel obviously reduced the inflammation around the wound and promoted the skin regeneration comparing with the control tests.