1.Analysis of the causes of cage subsidence after oblique lateral lumbar interbody fusion
Zhong-You ZENG ; Ping-Quan CHEN ; Xing ZHAO ; Hong-Fei WU ; Jian-Qiao ZHANG ; Xiang-Qian FANG ; Yong-Xing SONG ; Wei YU ; Fei PEI ; Shun-Wu FAN ; Guo-Hao SONG ; Shi-Yang FAN
China Journal of Orthopaedics and Traumatology 2024;37(1):33-44
		                        		
		                        			
		                        			Objective To observe the cage subsidence after oblique lateral interbody fusion(OLIF)for lumbar spondylo-sis,summarize the characteristics of the cage subsidence,analyze causes,and propose preventive measures.Methods The data of 144 patients of lumbar spine lesions admitted to our hospital from October 2015 to December 2018 were retrospectively ana-lyzed.There were 43 males and 101 females,and the age ranged from 20 to 81 years old,with an average of(60.90±10.06)years old.Disease types:17 patients of lumbar intervertebral disc degenerative disease,12 patients of giant lumbar disc hernia-tion,5 patients of discogenic low back pain,33 patients of lumbar spinal stenosis,26 patients of lumbar degenerative spondy-lolisthesis,28 patients of lumbar spondylolisthesis with spondylolisthesis,11 patients of adjacent vertebral disease after lumbar internal fixation,7 patients of primary spondylitis in the inflammatory outcome stage,and 5 patients of lumbar degenerative scoliosis.Preoperative dual-energy X-ray bone mineral density examination showed 57 patients of osteopenia or osteoporosis,and 87 patients of normal bone density.The number of fusion segments:124 patients of single-segment,11 patients of two-seg-ment,8 patients of three-segment,four-segment 1 patient.There were 40 patients treated by stand-alone OLIF,and 104 patients by OLIF combined with posterior pedicle screw.Observed the occurrence of fusion cage settlement after operation,conducted monofactor analysis on possible risk factors,and observed the influence of fusion cage settlement on clinical results.Results All operations were successfully completed,the median operation time was 99 min,and the median intraoperative blood loss was 106 ml.Intraoperative endplate injury occurred in 30 patients and vertebral fracture occurred in 5 patients.The mean follow-up was(14.57±7.14)months from 6 to 30 months.During the follow-up,except for the patients of primary lumbar interstitial in-flammation and some patients of lumbar spondylolisthesis with spondylolisthesis,the others all had different degrees of cage subsidence.Cage subsidence classification:119 patients were normal subsidence,and 25 patients were abnormal subsidence(23 patients were grade Ⅰ,and 2 patients were grade Ⅱ).There was no loosening or rupture of the pedicle screw system.The height of the intervertebral space recovered from the preoperative average(9.48±1.84)mm to the postoperative average(12.65±2.03)mm,and the average(10.51±1.81)mm at the last follow-up.There were statistical differences between postop-erative and preoperative,and between the last follow-up and postoperative.The interbody fusion rate was 94.4%.The low back pain VAS decreased from the preoperative average(6.55±2.2 9)to the last follow-up(1.40±0.82),and there was statistically significant different.The leg pain VAS decreased from the preoperative average(4.72±1.49)to the final follow-up(0.60± 0.03),and the difference was statistically significant(t=9.13,P<0.000 1).The ODI index recovered from the preoperative av-erage(38.50±6.98)%to the latest follow-up(11.30±3.27)%,and there was statistically significant different.The complication rate was 31.3%(45/144),and the reoperation rate was 9.72%(14/144).Among them,8 patients were reoperated due to fusion cage subsidence or displacement,accounting for 57.14%(8/14)of reoperation.The fusion cage subsidence in this group had obvious characteristics.The monofactor analysis showed that the number of abnormal subsidence patients in the osteopenia or osteoporosis group,Stand-alone OLIF group,2 or more segments fusion group,and endplate injury group was higher than that in the normal bone mass group,OLIF combined with pedicle screw fixation group,single segment fusion group,and no endplate injury group,and the comparison had statistical differences.Conclusion Cage subsidence is a common phenomenon after 0-LIF surgery.Preoperative osteopenia or osteoporosis,Stand-alone OLIF,2 or more segments of fusion and intraoperative end-plate injury may be important factors for postoperative fusion cage subsidence.Although there is no significant correlation be-tween the degree of cage subsidence and clinical symptoms,there is a risk of cage migration,and prevention needs to be strengthened to reduce serious complications caused by fusion of cage subsidence,including reoperation.
		                        		
		                        		
		                        		
		                        	
2.Advances in the research of HIV-1 envelope glycoprotein gp120 inhibitors
Ming-hui XIE ; Zhao WANG ; Yan-ying SUN ; Xiang-yi JIANG ; Peng ZHAN ; Xin-yong LIU ; Dong-wei KANG
Acta Pharmaceutica Sinica 2023;58(3):616-628
		                        		
		                        			
		                        			 From the process of human immunodeficiency virus-1 (HIV-1) invading cells, the combination of gp120 and CD4 is the first step for HIV-1 to invade cells. Interfering with this process can prevent HIV from recognizing target cells and inhibit virus replication. Therefore, HIV-1 gp120 is an important part of the HIV-1 life cycle. Fostesavir, a phosphatate prodrug derived from the gp120 inhibitor BMS-626529 modified by the prodrug strategy, was approved for the treatment of adult patients with multidrug resistant HIV-1 infection by the US FDA and the European Medicines Agency in 2020 and 2021, respectively. In this review, we focus on the research progress of small molecule inhibitors targeting the interaction of gp120-CD4 from the perspective of medicinal chemistry, in order to provide reference for the subsequent research of gp120 inhibitors. 
		                        		
		                        		
		                        		
		                        	
3.Chemical constituents of diterpenoids from Boswellia carterii.
Rong-Ye WANG ; Hui XIA ; Yong-Xiang WANG ; Hao HUANG ; Bo-Kai WANG ; Meng DU ; Yue-Lin SONG ; Yun-Fang ZHAO ; Jiao ZHENG ; Hui-Xia HUO ; Jun LI
China Journal of Chinese Materia Medica 2023;48(9):2464-2470
		                        		
		                        			
		                        			This paper explored the chemical constituents of Boswellia carterii by column chromatography on silica gel, Sephadex LH-20, ODS column chromatography, and semi-preparative HPLC. The structures of the compounds were identified by physicochemical properties and spectroscopic data such as infrared radiation(IR), ultra violet(UV), mass spectrometry(MS), and nuclear magnetic resonance(NMR). Seven diterpenoids were isolated and purified from n-hexane of B. carterii. The isolates were identified as(1S,3E,7E,11R,12R)-11-hydroxy-1-isopropyl-4,8,12-trimethyl-15-oxabicyclo[10.2.1]pentadeca-3,7-dien-5-one(1),(1R,3S,4R,7E,11E)-4,8,12,15,15-pentamethyl-14-oxabicyclo[11.2.1]hexadeca-7,11-dien-4-ol(2), incensole(3),(-)-(R)-nephthenol(4), euphraticanoid F(5), dilospirane B(6), and dictyotin C(7). Among them, compounds 1 and 2 were new and their absolute configurations were determined by comparison of the calculated and experimental electronic circular dichroisms(ECDs). Compounds 6 and 7 were obtained from B. carterii for the first time.
		                        		
		                        		
		                        		
		                        			Molecular Structure
		                        			;
		                        		
		                        			Boswellia/chemistry*
		                        			;
		                        		
		                        			Diterpenes/chemistry*
		                        			;
		                        		
		                        			Mass Spectrometry
		                        			
		                        		
		                        	
4.Clinical and genetic characteristic in patients with disorders of sex development caused by Y chromosome copy number variant.
Jun Ke XIA ; Feng Yan TIAN ; Ya Qin HOU ; Yong Jiang ZHAO ; Xiang Dong KONG
Chinese Journal of Pediatrics 2023;61(5):459-463
		                        		
		                        			
		                        			Objective: To investigate the clinical phenotype and genetic characteristics of disorders of sex development (DSD) caused by Y chromosome copy number variant (CNV). Methods: A retrospective analysis was performed on 3 patients diagnosed with DSD caused by Y chromosome CNV admitted to the First Affiliated Hospital of Zhengzhou University from January, 2018 to September, 2022. Clinical data were collected. Clinical study and genetic test were performed by karyotyping, whole exome sequencing (WES), low coverage whole genome copy number variant sequencing (CNV-seq), fluorescence in situ hybridization (FISH) and gonadal biopsy. Results: The 3 children, aged 12, 9, 9 years, the social gender were all female, presented with short stature, gonadal dysplasia and normal female external genital. No other phenotypic abnormality was found except for case 1 with scoliosis. The karyotype of all cases were identified as 46, XY. No pathogenic vraiants were found by WES. CNV-seq determined that case 1 was 47, XYY,+Y(2.12) and case 2 was 46, XY,+Y(1.6). FISH concluded that the long arm of Y chromosome was broken and recombined near Yq11.2, and then produced a pseudodicentric chromosome idic(Y). The karyotype was reinterpreted as mos 47, X, idic(Y)(q11.23)×2(10)/46, X, idic(Y)(q11.23)(50) in case 1. The karyotype was redefined as 45, XO(6)/46, X, idic(Y)(q11.22)(23)/46, X, del(Y)(q11.22)(1) in case 2. 46, XY, -Y(mos) was found by CNV-seq in case 3, and the karyotype of 45, XO/46, XY was speculated. Conclusions: The clinical manifestations of children with DSD caused by Y chromosome CNV are short stature and gonadal dysgenesis. If there is an increase of Y chromosome CNV detected by CNV-seq, FISH is recommended to classify the structural variation of Y chromosome.
		                        		
		                        		
		                        		
		                        			Humans
		                        			;
		                        		
		                        			Female
		                        			;
		                        		
		                        			DNA Copy Number Variations
		                        			;
		                        		
		                        			In Situ Hybridization, Fluorescence
		                        			;
		                        		
		                        			Retrospective Studies
		                        			;
		                        		
		                        			Chromosomes, Human, Y
		                        			;
		                        		
		                        			Turner Syndrome
		                        			
		                        		
		                        	
5.Preliminary study on three-dimensional morphological reconstruction method for external nose defect based on three-dimensional face template.
Ao Nan WEN ; Yong WANG ; Hong Qiang YE ; Zi Xiang GAO ; Yu Jia ZHU ; Qing Zhap QIN ; Hui Zhen HU ; Yun Song LIU ; Yi Jiao ZHAO
Chinese Journal of Stomatology 2023;58(5):414-421
		                        		
		                        			
		                        			Objective: To provide a new solution for the digital design of nasal prostheses, this study explores the three-dimensional (3D) facial morphology completion method for external nasal defects based on the non-rigid registration process of 3D face template. Methods: A total of 20 male patients with tooth defect and dentition defect who visited the Department of Prosthodontics, Peking University School and Hospital of Stomatology from June to December 2022 were selected, age 18-45 years old. The original 3D facial data of patients were collected, and the 3D facial data of the external nose defect was constructed in Geomagic Wrap 2021 software. Using the structured 3D face template data constructed in the previous research of the research group, the 3D face template was deformed and registered to the 3D facial data of external nose defect (based on the morphology of non-defective area) by non-rigid registration algorithm (MeshMonk program), and the personalized deformed data of the 3D face template was obtained, as the complemented facial 3D data. Based on the defect boundary of the 3D facial data of the external nose defect, the complemented external nose 3D data can be cut out from the complemented facial 3D data. Then the nasofacial angle and nasolabial angle of the complemented facial 3D data and the original 3D facial data was compared and analyzed, the ratio between the nose length and mid-face height, nose width and medial canthal distance of the complemented facial 3D data was measured, the edge fit between the edge curve of the complemented external nose 3D data and the defect edge curve of the 3D facial data of external nose defect was evaluated, and the morphological difference of the nose between the complemented external nose 3D data and the original 3D facial data was analyzed. Results: There was no significant statistically difference (t=-0.23, P=0.823; Z=-1.72, P=0.086) in the nasofacial angle (28.2°±2.9°, 28.4°±3.5° respectively) and nasolabial angle [95.4°(19.2°), 99.9°(9.5°) respectively] between the 20 original 3D facial data and the complemented facial 3D data. The value of the ratio of nose length to mid-face height in the complemented facial 3D data was 0.63±0.03, and the value of the ratio of nose width to medial canthal distance was 1.07±0.08. The curve deviation (root mean square value) between the edge curve of the complemented external nose 3D data and the defect edge curve of the 3D facial data of external nose defect was (0.37±0.09) mm, the maximum deviation was (1.14±0.32) mm, and the proportion of the curve deviation value within±1 mm was (97±3)%. The distance of corresponding nose landmarks between the complemented facial 3D data and the original 3D facial data were respectively, Nasion: [1.52(1.92)] mm; Pronasale: (3.27±1.21) mm; Subnasale: (1.99±1.09) mm; Right Alare: (2.64±1.34) mm; Left Alare: (2.42± 1.38) mm. Conclusions: The method of 3D facial morphology completion of external nose defect proposed in this study has good feasibility. The constructed complemented external nose 3D data has good facial coordination and edge fit, and the morphology is close to the nose morphology of the original 3D facial data.
		                        		
		                        		
		                        		
		                        	
6.The design method of the digital sequential tooth-sectioning guide for the extraction of mandibular impacted third molars.
Zi Xiang GAO ; Yi Jiao ZHAO ; Yu Jia ZHU ; Ning XIAO ; Ao Nan WEN ; Wei ZHOU ; Bo Chun MAO ; Yun ZHANG ; Wei QI ; Yong WANG
Chinese Journal of Stomatology 2023;58(5):435-441
		                        		
		                        			
		                        			Objective: To explore a method for digitally designing and fabricating a sequential tooth-sectioning guide that can assist in the extraction of mandibular horizontal impacted third molars, preliminarily evaluate its feasibility and provide a reference for clinical application. Methods: Twenty patients with mandibular low level impacted third molars who visited the Department of General Dentistry, Peking University School and Hospital of Stomatology from March 2021 to January 2022 were selected. Cone-beam CT showed direct contact between the roots and mandibular canal, and full range impressions of the patients' intraoral teeth were taken and optical scans of the dental model were performed. The patients' cone-beam CT data and optical scan data were reconstructed in three dimensions, anatomical structure extraction, registration fusion, and the design of the structure of the guide (including crown-sectioning guide and root-sectioning guide) by Mimics 24.0, Geomagic Wrap 2021, and Magics 21.0 software, and then the titanium guide was three dimension printed, and the guide was tried on the dental model. After confirmation, the guide was used to assist the dentist in the operation. We observed whether the guide was in place, the number of tooth splitting, the matching of tooth splitting with the preoperative design, the operation time, and whether there were any complications. Results: In this study, 20 sectioning guides were successfully printed, all of them were well fitted in the patients' mouth, the average number of section was 3.4 times, the tooth parts was better matched with the preoperative design, and the average operative time of the guides was (29.2±9.8) minutes without complications such as perforation of the bone cortex. Conclusions: The use of sequential sectioning guides to assist in the extraction of mandibular impacted third molars was initially validated to accurately replicate the preoperative sectioning design, and is expected to provide a digital solution to improve surgical precision and ensure safety. Further studies with larger sample sizes are needed to evaluate its accuracy and safety.
		                        		
		                        		
		                        		
		                        	
7.Study on the method of automatically determining maxillary complex landmarks based on non-rigid registration algorithms.
Zi Xiang GAO ; Jing WANG ; Ao Nan WEN ; Yu Jia ZHU ; Qing Zhao QIN ; Yong WANG ; Yi Jiao ZHAO
Chinese Journal of Stomatology 2023;58(6):554-560
		                        		
		                        			
		                        			Objective: To explore an automatic landmarking method for anatomical landmarks in the three-dimensional (3D) data of the maxillary complex and preliminarily evaluate its reproducibility and accuracy. Methods: From June 2021 to December 2022, spiral CT data of 31 patients with relatively normal craniofacial morphology were selected from those who visited the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology. The sample included 15 males and 16 females, with the age of (33.3±8.3) years. The maxillary complex was reconstructed in 3D using Mimics software, and the resulting 3D data of the maxillary complex was mesh-refined using Geomagic software. Two attending physicians and one associate chief physician manually landmarked the 31 maxillary complex datasets, determining 24 anatomical landmarks. The average values of the three expert landmarking results were used as the expert-defined landmarks. One case that conformed to the average 3D morphological characteristics of healthy individuals' craniofacial bones was selected as the template data, while the remaining 30 cases were used as target data. The open-source MeshMonk program (a non-rigid registration algorithm) was used to perform an initial alignment of the template and target data based on 4 landmarks (nasion, left and right zygomatic arch prominence, and anterior nasal spine). The template data was then deformed to the shape of the target data using a non-rigid registration algorithm, resulting in the deformed template data. Based on the unchanged index property of homonymous landmarks before and after deformation of the template data, the coordinates of each landmark in the deformed template data were automatically retrieved as the automatic landmarking coordinates of the homonymous landmarks in the target data, thus completing the automatic landmarking process. The automatic landmarking process for the 30 target data was repeated three times. The root-mean-square distance (RMSD) of the dense corresponding point pairs (approximately 25 000 pairs) between the deformed template data and the target data was calculated as the deformation error of the non-rigid registration algorithm, and the intra-class correlation coefficient (ICC) of the deformation error in the three repetitions was analyzed. The linear distances between the automatic landmarking results and the expert-defined landmarks for the 24 anatomical landmarks were calculated as the automatic landmarking errors, and the ICC values of the 3D coordinates in the three automatic landmarking repetitions were analyzed. Results: The average three-dimensional deviation (RMSD) between the deformed template data and the corresponding target data for the 30 cases was (0.70±0.09) mm, with an ICC value of 1.00 for the deformation error in the three repetitions of the non-rigid registration algorithm. The average automatic landmarking error for the 24 anatomical landmarks was (1.86±0.30) mm, with the smallest error at the anterior nasal spine (0.65±0.24) mm and the largest error at the left oribital (3.27±2.28) mm. The ICC values for the 3D coordinates in the three automatic landmarking repetitions were all 1.00. Conclusions: This study established an automatic landmarking method for three-dimensional data of the maxillary complex based on a non-rigid registration algorithm. The accuracy and repeatability of this method for landmarking normal maxillary complex 3D data were relatively good.
		                        		
		                        		
		                        		
		                        			Male
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		                        			Female
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		                        			Humans
		                        			;
		                        		
		                        			Adult
		                        			;
		                        		
		                        			Imaging, Three-Dimensional/methods*
		                        			;
		                        		
		                        			Reproducibility of Results
		                        			;
		                        		
		                        			Algorithms
		                        			;
		                        		
		                        			Software
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		                        			Tomography, Spiral Computed
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		                        			Anatomic Landmarks/anatomy & histology*
		                        			
		                        		
		                        	
8.Precise application of Beichaihu and Nanchaihu in classical formulas.
Yu-Ping SHE ; Pei-Pei ZHANG ; Jing-Yan HU ; Yong-Hua GUO ; Qian CAO ; Xiang YIN ; Xiu-Hua HU ; Ting ZHAO ; Feng-Bo LIU ; Yuan ZHANG ; Sheng-Li WEI
China Journal of Chinese Materia Medica 2023;48(3):681-688
		                        		
		                        			
		                        			To maintain the precision and stability of the efficacy of classical formulas, this study compared the origins and specifications of Bupleuri Radix and revealed the precise application regularity of Bupleurum chinense(Beichaihu) and Bupleurum scorzonerifolium(Nanchaihu) in classical formulas. The efficacy and indications of formulas with Bupleuri Radix as the sovereign drug in the Treatise on Cold Damage and Miscellaneous Diseases(Shang Han Za Bing Lun) were investigated. The difference in the efficacy of Bupleuri Radix as well as the differences in the chemical composition, and liver-protecting and lipid-lowering effects of the decoctions of Beichaihu and Nanchaihu were analyzed with LC-MS technology based on the CCl_4-induced liver injury model in mice and sodium oleate-induced HepG2 hyperlipidemia cell model. The results showed that seven classical formulas with Bupleuri Radix as the sovereign drug in the Treatise on Cold Damage and Miscellaneous Diseases were mainly used in the treatment of digestive, metabolic, immune, circulatory, and other diseases. Bupleuri Radix mainly played the functions of protecting the liver, benefiting the gallbladder, and lowering the lipid, and had different focuses in different formulas. There were 14 differential components in the decoctions of Beichaihu and Nanchaihu, and the chemical structures of 11 components were identified, including 10 saponins and one flavonoid. The results of the liver-protecting efficacy experiment showed that compared with the Nanchaihu decoction, Beichaihu decoction could reduce the serum aspartate aminotransferase(AST) activity in liver injury model mice(P<0.01). The results of the lipid-lowering efficacy experiment proved that Beichaihu and Nanchaihu decoctions both showed highly significant differences in lowering the total cholesterol(TC) and triglyceride(TG) content in HepG2 cells(P<0.01), and Nanchaihu decoction was superior to Beichaihu decoction in lowering the lipid. The results of this study preliminarily proved that there were differences in chemical composition, and liver-protecting and lipid-lowering effects of Beichaihu and Nanchaihu decoctions, indicating that it was necessary to determine the precise origin of Bupleuri Radix in the clinical formulation of traditional Chinese medicine. The study provides a scientific basis for both precise clinical medication and purpose-based accurate quality evaluation of traditional Chinese medicine in clinical application.
		                        		
		                        		
		                        		
		                        			Animals
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		                        			Mice
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		                        			Liver
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		                        			Aspartate Aminotransferases
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		                        			Bupleurum
		                        			
		                        		
		                        	
9.Application of oblique lateral interbody fusion in the treatment of lumbar intervertebral disc degeneration in patients with Modic change and endplate sclerosis.
Ping-Quan CHEN ; Zhong-You ZENG ; Xing ZHAO ; Shi-Yang FAN ; Hong-Fei WU ; Wei YU ; Jian-Qiao ZHANG ; Yong-Xing SONG ; Shun-Wu FAN ; Xiang-Qian FANG ; Fei PEI ; Guo-Hao SONG
China Journal of Orthopaedics and Traumatology 2023;36(1):29-37
		                        		
		                        			OBJECTIVE:
		                        			To explore the feasibility and clinical effect of Stand-alone oblique lateral interbody fusion (OLIF) in the treatment of lumbar intervertebral disc degeneration with Modic changes and endplate sclerosis.
		                        		
		                        			METHODS:
		                        			A retrospective analysis was performed on 16 cases with lumbar intervertebral disc degeneration with Modic changes and endplate sclerosis admitted to three medical centers from January 2015 to December 2018. There were 6 males and 10 females, the age ranged from 45 to 67 years old with an average of (55.48±8.07) years old, the medical history ranged from 36 to 240 months with an average of (82.40±47.68) months. The lesion sites included L2,3 in 2 cases, L3,4 in 5 cases, and L4,5 in 9 cases. All patients presented with chronic low back pain with lower limb neurological symptoms in 3 cases. All patients were treated by Stand-alone oblique lateral lumbar interbody fusion. Clinical and radiological findings and complications were observed.
		                        		
		                        			RESULTS:
		                        			There was no vascular injury, endplate injury and vertebral fracture during the operation. The mean incision length, operation time, and intraoperative blood loss were(4.06±0.42) cm, (45.12±5.43) min, (33.40±7.29) ml, respectively. The mean visual analogue scale (VAS) of the incision pain was (1.14±0.47) at 72 hours after operation. There was no incision skin necrosis, poor incision healing or infection in patients. Sympathetic chain injury occurred in 1 case, anterolateral pain and numbness of the left thigh in 2 cases, and weakness of the left iliopsoas muscle in 1 case, all of which were transient injuries with a complication rate of 25%(4/16). All 16 patients were followed up from 12 to 36 months with an average of (20.80±5.46) months. The intervertebral space height was significantly recovered after operation, with slight lost during the follow-up. Coronal and sagittal balance of the lumbar spine showed good improvement at the final follow-up. There was no obvious subsidence or displacement of the cage, and the interbody fusion was obtained. At the final follow-up, Japanese Orthopaedic Association(JOA) score and Oswestry disability index(ODI) were significantly improved.
		                        		
		                        			CONCLUSION
		                        			As long as the selection of case is strict enough and the preoperative examination is sufficients, the use of Stand-alone OLIF in the treatment of lumbar intervertebral disc degeneration with Modic changes and endplate sclerosis has a good results, with obvious clinical advantages and is a better surgical choice.
		                        		
		                        		
		                        		
		                        			Male
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		                        			Female
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		                        			Humans
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		                        			Child, Preschool
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		                        			Intervertebral Disc Degeneration/surgery*
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		                        			Retrospective Studies
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		                        			Sclerosis
		                        			;
		                        		
		                        			Treatment Outcome
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		                        			Lumbar Vertebrae/surgery*
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		                        			Spinal Fusion/methods*
		                        			
		                        		
		                        	
10.Automatic determination of mandibular landmarks based on three-dimensional mandibular average model.
Zi Xiang GAO ; Yong WANG ; Ao Nan WEN ; Yu Jia ZHU ; Qing Zhao QIN ; Yun ZHANG ; Jing WANG ; Yi Jiao ZHAO
Journal of Peking University(Health Sciences) 2023;55(1):174-180
		                        		
		                        			OBJECTIVE:
		                        			To explore an efficient and automatic method for determining the anatomical landmarks of three-dimensional(3D) mandibular data, and to preliminarily evaluate the performance of the method.
		                        		
		                        			METHODS:
		                        			The CT data of 40 patients with normal craniofacial morphology were collected (among them, 30 cases were used to establish the 3D mandibular average model, and 10 cases were used as test datasets to validate the performance of this method in determining the mandibular landmarks), and the 3D mandibular data were reconstructed in Mimics software. Among the 40 cases of mandibular data after the 3D reconstruction, 30 cases that were more similar to the mean value of Chinese mandibular features were selected, and the size of the mandibular data of 30 cases was normalized based on the Procrustes analysis algorithm in MATLAB software. Then, in the Geomagic Wrap software, the 3D mandibular average shape model of the above 30 mandibular data was constructed. Through symmetry processing, curvature sampling, index marking and other processing procedures, a 3D mandible structured template with 18 996 semi-landmarks and 19 indexed mandibular anatomical landmarks were constructed. The open source non-rigid registration algorithm program Meshmonk was used to match the 3D mandible template constructed above with the tested patient's 3D mandible data through non-rigid deformation, and 19 anatomical landmark positions of the patient's 3D mandible data were obtained. The accuracy of the research method was evaluated by comparing the distance error of the landmarks manually marked by stomatological experts with the landmarks marked by the method of this research.
		                        		
		                        			RESULTS:
		                        			The method of this study was applied to the data of 10 patients with normal mandibular morphology. The average distance error of 19 landmarks was 1.42 mm, of which the minimum errors were the apex of the coracoid process [right: (1.01±0.44) mm; left: (0.56±0.14) mm] and maximum errors were the anterior edge of the lowest point of anterior ramus [right: (2.52±0.95) mm; left: (2.57±1.10) mm], the average distance error of the midline landmarks was (1.15±0.60) mm, and the average distance error of the bilateral landmarks was (1.51±0.67) mm.
		                        		
		                        			CONCLUSION
		                        			The automatic determination method of 3D mandibular anatomical landmarks based on 3D mandibular average shape model and non-rigid registration algorithm established in this study can effectively improve the efficiency of automatic labeling of 3D mandibular data features. The automatic determination of anatomical landmarks can basically meet the needs of oral clinical applications, and the labeling effect of deformed mandible data needs to be further tested.
		                        		
		                        		
		                        		
		                        			Humans
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		                        			Imaging, Three-Dimensional/methods*
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		                        			Mandible/diagnostic imaging*
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		                        			Software
		                        			;
		                        		
		                        			Algorithms
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		                        			Anatomic Landmarks/anatomy & histology*
		                        			
		                        		
		                        	
            
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