1.Prognosis and its influencing factors in patients with non-gastric gastrointestinal stromal tumors at low risk of recurrence: a retrospective multicenter study in China
Linxi YANG ; Weili YANG ; Xin WU ; Peng ZHANG ; Bo ZHANG ; Junjun MA ; Xinhua ZHANG ; Haoran QIAN ; Ye ZHOU ; Tao CHEN ; Hao XU ; Guoli GU ; Zhidong GAO ; Gang ZHAI ; Xiaofeng SUN ; Changqing JING ; Haibo QIU ; Xiaodong GAO ; Hui CAO ; Ming WANG
Chinese Journal of Gastrointestinal Surgery 2024;27(11):1123-1132
Objective:To investigate the prognosis and the factors that influence it in patients with non-gastric gastrointestinal stromal tumors (GISTs) who are at low risk of recurrence.Methods:This was a retrospective cohort study. Clinicopathologic and prognostic data from patients with non-gastric GISTs and at low risk of recurrence (i.e., very low-risk or low-risk according to the 2008 version of the Modified NIH Risk Classification), who attended 18 medical centers in China between January 2000 and June 2023, were collected. We excluded patients with a history of prior malignancy, concurrent primary malignancy, multiple GISTs, and those who had received preoperative imatinib. The study cohort comprised 1,571 patients with GISTs, 370 (23.6%) of whom were at very low-risk and 1,201 (76.4%) at low-risk of recurrence. The cohort included 799 (50.9%) men and 772 (49.1%) women of median age 57 (16–93) years. Patients were followed up to July 2024. The prognosis and its influencing factors were analyzed. Receiver operating characteristic curves for tumor diameter and Ki67 were established, and the sensitivity, specificity, area under the curve (AUC) and optimal cut-off value with 95% confidence intervals were calculated. Propensity score matching was implemented using the 1:1 nearest neighbor matching method with a matching tolerance of 0.02.Results:With a median follow-up of 63 (12–267) months, the 5- and 10-year overall survival (OS) rates of the 1,571 patients were 99.5% and 98.0%, respectively, and the 5- and 10-year disease-free survival (DFS) rates were 96.3% and 94.4%, respectively. During postoperative follow-up, 3.8% (60/1,571) patients had disease recurrence or metastasis, comprising 0.8% (3/370) in the very low-risk group and 4.7% (57/1,201) in the low-risk group. In the low-risk group, recurrence or metastasis occurred in 5.5% (25/457) of patients with duodenal GISTs, 3.9% (25/645) of those with small intestinal GISTs, 9.2% (6/65) of those with rectal GISTs, and 10.0% (1/10) of those with colonic GISTs. Among the 60 patients with metastases, 56.7% (34/60) of the metastases were located in the abdominal cavity, 53.3% (32/60) in the liver, and 3.3% (2/60) in bone. During the follow-up period, 13 patients (0.8%) died of disease. Receiver operating characteristic curves were plotted for tumor diameter and Ki67 and assessed using the Jordon index. This showed that the difference in DFS between the two groups was statistically significant when the cutoff value for tumor diameter was 3.5 cm (AUC 0.731, 95% CI: 0.670–0.793, sensitivity 77.7%, specificity 64.1%). Furthermore, the difference in DFS between the two groups was statistically significant when the cutoff value for Ki67 was 5% (AUC 0.693, 95% CI: 0.624–0.762, sensitivity 60.7%, specificity 65.3%). Multifactorial analysis revealed that tumor diameter ≥3.5 cm, Ki67 ≥5%, and R1 resection were independent risk factors for DFS in patients with non-gastric GISTs at low risk of recurrence (all P<0.05). Furthermore, age >57 years, Ki67 ≥5%, and R1 resection were also independent risk factors for OS in patients with non-gastric GISTs at low risk of recurrence (all P<0.05). We also grouped the patients according to whether they had received postoperative adjuvant treatment with imatinib for 1 or 3 years. This yielded 137 patients in the less than 1-year group, 139 in the 1-year plus group; and 44 in both the less than 3 years and 3-years plus group. After propensity score matching for age, tumor diameter, Ki67, and resection status, the differences in survival between the two groups were not statistically significant (all P>0.05). The 10-year DFS and OS were 87.5% and 95.5%, respectively, in the group treated with imatinib for less than 1 year and 88.5% and 97.8%, respectively, in the group treated for more than 1 year. The 10-year DFS and OS were 89.6% and 92.6%, respectively, in the group treated with imatinib for less than 3 years and 88.0% and 100.0%, respectively, in the group treated with imatinib for more than 3 years. Conclusion:The overall prognosis of primary, non-gastric, low recurrence risk GISTs is relatively favorable; however, recurrences and metastases do occur. Age, tumor diameter, Ki67, and R1 resection may affect the prognosis. For some patients with low risk GISTs, administration of adjuvant therapy with imatinib for an appropriate duration may help prevent recurrence and improve survival.
2.Prognosis and its influencing factors in patients with non-gastric gastrointestinal stromal tumors at low risk of recurrence: a retrospective multicenter study in China
Linxi YANG ; Weili YANG ; Xin WU ; Peng ZHANG ; Bo ZHANG ; Junjun MA ; Xinhua ZHANG ; Haoran QIAN ; Ye ZHOU ; Tao CHEN ; Hao XU ; Guoli GU ; Zhidong GAO ; Gang ZHAI ; Xiaofeng SUN ; Changqing JING ; Haibo QIU ; Xiaodong GAO ; Hui CAO ; Ming WANG
Chinese Journal of Gastrointestinal Surgery 2024;27(11):1123-1132
Objective:To investigate the prognosis and the factors that influence it in patients with non-gastric gastrointestinal stromal tumors (GISTs) who are at low risk of recurrence.Methods:This was a retrospective cohort study. Clinicopathologic and prognostic data from patients with non-gastric GISTs and at low risk of recurrence (i.e., very low-risk or low-risk according to the 2008 version of the Modified NIH Risk Classification), who attended 18 medical centers in China between January 2000 and June 2023, were collected. We excluded patients with a history of prior malignancy, concurrent primary malignancy, multiple GISTs, and those who had received preoperative imatinib. The study cohort comprised 1,571 patients with GISTs, 370 (23.6%) of whom were at very low-risk and 1,201 (76.4%) at low-risk of recurrence. The cohort included 799 (50.9%) men and 772 (49.1%) women of median age 57 (16–93) years. Patients were followed up to July 2024. The prognosis and its influencing factors were analyzed. Receiver operating characteristic curves for tumor diameter and Ki67 were established, and the sensitivity, specificity, area under the curve (AUC) and optimal cut-off value with 95% confidence intervals were calculated. Propensity score matching was implemented using the 1:1 nearest neighbor matching method with a matching tolerance of 0.02.Results:With a median follow-up of 63 (12–267) months, the 5- and 10-year overall survival (OS) rates of the 1,571 patients were 99.5% and 98.0%, respectively, and the 5- and 10-year disease-free survival (DFS) rates were 96.3% and 94.4%, respectively. During postoperative follow-up, 3.8% (60/1,571) patients had disease recurrence or metastasis, comprising 0.8% (3/370) in the very low-risk group and 4.7% (57/1,201) in the low-risk group. In the low-risk group, recurrence or metastasis occurred in 5.5% (25/457) of patients with duodenal GISTs, 3.9% (25/645) of those with small intestinal GISTs, 9.2% (6/65) of those with rectal GISTs, and 10.0% (1/10) of those with colonic GISTs. Among the 60 patients with metastases, 56.7% (34/60) of the metastases were located in the abdominal cavity, 53.3% (32/60) in the liver, and 3.3% (2/60) in bone. During the follow-up period, 13 patients (0.8%) died of disease. Receiver operating characteristic curves were plotted for tumor diameter and Ki67 and assessed using the Jordon index. This showed that the difference in DFS between the two groups was statistically significant when the cutoff value for tumor diameter was 3.5 cm (AUC 0.731, 95% CI: 0.670–0.793, sensitivity 77.7%, specificity 64.1%). Furthermore, the difference in DFS between the two groups was statistically significant when the cutoff value for Ki67 was 5% (AUC 0.693, 95% CI: 0.624–0.762, sensitivity 60.7%, specificity 65.3%). Multifactorial analysis revealed that tumor diameter ≥3.5 cm, Ki67 ≥5%, and R1 resection were independent risk factors for DFS in patients with non-gastric GISTs at low risk of recurrence (all P<0.05). Furthermore, age >57 years, Ki67 ≥5%, and R1 resection were also independent risk factors for OS in patients with non-gastric GISTs at low risk of recurrence (all P<0.05). We also grouped the patients according to whether they had received postoperative adjuvant treatment with imatinib for 1 or 3 years. This yielded 137 patients in the less than 1-year group, 139 in the 1-year plus group; and 44 in both the less than 3 years and 3-years plus group. After propensity score matching for age, tumor diameter, Ki67, and resection status, the differences in survival between the two groups were not statistically significant (all P>0.05). The 10-year DFS and OS were 87.5% and 95.5%, respectively, in the group treated with imatinib for less than 1 year and 88.5% and 97.8%, respectively, in the group treated for more than 1 year. The 10-year DFS and OS were 89.6% and 92.6%, respectively, in the group treated with imatinib for less than 3 years and 88.0% and 100.0%, respectively, in the group treated with imatinib for more than 3 years. Conclusion:The overall prognosis of primary, non-gastric, low recurrence risk GISTs is relatively favorable; however, recurrences and metastases do occur. Age, tumor diameter, Ki67, and R1 resection may affect the prognosis. For some patients with low risk GISTs, administration of adjuvant therapy with imatinib for an appropriate duration may help prevent recurrence and improve survival.
3.Early effectiveness of computer navigation system-assisted transiliac-transsacral screws placement for posterior pelvic ring injuries.
Wenhao CAO ; Zhengguo ZHU ; Hongzhe QI ; Junjun TANG ; Wei ZHANG ; Jiaqi LI ; Shuangcheng LI ; Zhonghe WANG ; Changda LI ; Feng ZHOU ; Haoyang LIU ; Hua CHEN ; Peifu TANG
Chinese Journal of Reparative and Reconstructive Surgery 2023;37(9):1049-1054
OBJECTIVE:
To investigate the early effectiveness of transiliac-transsacral screws internal fixation assisted by augmented reality navigation system HoloSight (hereinafter referred to as "computer navigation system") in the treatment of posterior pelvic ring injuries.
METHODS:
A retrospective analysis was made in the 41 patients with posterior pelvic ring injuries who had been treated surgically with transiliac-transsacral screws between June 2022 and June 2023. The patients were divided into navigation group (18 cases, using computer navigation system to assist screw implantation) and freehand group (23 cases, using C-arm X-ray fluoroscopy to guide screw implantation) according to the different methods of transiliac-transsacral screws placement. There was no significant difference in gender, age, body mass index, causes of injuries, Tile classification of pelvic fracture, days from injury to operation, usage of unlocking closed reduction technique between the two groups ( P>0.05). The time of screw implantation, the fluoroscopy times, the guide wire adjustment times of each screw, and the incidence of complications were recorded and compared between the two groups. The position of the transiliac-transsacral screw was scanned by CT within 2 days after operation, and the position of the screw was classified according to Gras standard.
RESULTS:
The operation was successfully completed in both groups. The time of screw implantation, the fluoroscopy times, and the guide wire adjustment times of each screw in the navigation group were significantly less than those in the freehand group ( P<0.05). There were 2 cases of incision infection in the freehand group, and the incision healed by first intention after active dressing change; there was no screw-related complication in the navigation group during operation and early period after operation; the difference in incidence of complications between the two groups (8.7% vs. 0) was not significant ( P=0.495). According to the Gras standard, the screw position of the navigation group was significantly better than that of the freehand group ( P<0.05).
CONCLUSION
Compared with the traditional freehand method, the computer navigation system assisted transiliac-transsacral screws internal fixation in the treatment of posterior pelvic ring injuries has advantages of improving the accuracy of screw implantation and reducing radiation damage and the time of screw implantation.
Humans
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Retrospective Studies
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Surgical Wound Infection
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Replantation
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Body Mass Index
4.Oncological and reproductive outcomes after fertility-sparing surgery in patients with seromucinous borderline ovarian tumor: results of a large retrospective study
Dan WANG ; Shuangzheng JIA ; Congwei JIA ; Dongyan CAO ; Jiaxin YANG ; Junjun YANG ; Yang XIANG
Journal of Gynecologic Oncology 2022;33(S1):S5-
Objective:
To evaluate the oncological and reproductive outcomes in patients with seromucinous borderline ovarian tumors (SMBOT) treated with fertility-sparing surgery (FSS).
Methods:
We retrospectively reviewed the medical records of patients with SMBOT who underwent surgery between 2000 and 2019. A centralized histological review was performed and recurrence rates were compared between different surgical procedures.
Results:
A total of 105 patients fulfilled the inclusion criteria, of whom 65 underwent FSS and 40 were treated with radical surgery. Fourteen patients had recurrent disease after a median follow-up time of 59.6 months (range: 22.1–256.8 months). All but one relapsed with SMBOT. There was no significant difference in disease-free survival (DFS) between the 2 groups (p=0.141). Multivariate analysis showed that only bilateral involvement was associated with increased recurrence (p=0.008). In the subgroup of patients treated with conservative surgery, there was no significant difference in DFS with regard to surgical procedures (ovarian cystectomy vs. salpingo-oophorectomy, p=0.487). Of the 12 patients in the FSS group who developed recurrence, 11 underwent a second round of FSS and all remained alive with no evidence of disease at the end of follow-up. Of 20 patients desiring pregnancy, 16 patients were successful and resulted in 17 term deliveries.
Conclusion
FSS is feasible for young patients who wish to preserve their fertility. Patients initially treated with ovarian cystectomy may be managed by close surveillance if post-operative imaging are negative. Repeat FSS remains a valuable alternative for young patients with recurrent SMBOT after thorough communication.
5.Clinical features of severe adenovirus pneumonia with bacterial infection in children
Lifang ZHOU ; Zhenrong OUYANG ; Chongwei HAO ; Junjun LI ; Chenning CAO ; Shuangjie LI ; Yefei LEI
Chinese Pediatric Emergency Medicine 2022;29(6):446-450
Objective:To analyze the clinical characteristics of severe adenovirus pneumonia with bacterial infection in children, so as to provide clinical evidences for early diagnosis and reliable treatment.Methods:A total of 72 pediatric cases with severe adenovirus pneumonia admitted to Pediatric Intensive Care Unit at the First People′s Hospital of Chenzhou from January 2018 to August 2019 were included.The clinical features, laboratory and imaging data, efficacy of the treatments and prognosis were investigated retrospectively.Patients were divided into with bacterial infection group and without bacterial infection group.The clinical characteristics were analyzed.Results:Among the 72 children, there were 54 males and 18 females, aging from 3 months to 5 years, including 37cases with bacterial infection and 35 cases without bacterial infection.Compared with the group without bacterial infection, the group with bacterial infection had longer heat duration and hospital stay [12.0 (10.0, 18.5) days vs.10.0 (9.0, 12.0) days; 6.0(4.0, 7.0) days vs.11.0(6.5, 16.0) days, P<0.05], the incidences of diarrhea and hepatomegaly were higher[35.1% (13/37) vs.14.3%(5/35); 45.9%(17/37)vs.8.6%(3/35), P<0.05], the proportion of five lobes involved in lung imaging was higher [91.8% (34/37) vs. 57.1%(20/35), P<0.05]. The incidences of complications with respiratory failure, hemophagocytic lymphohistiocytosis, and bronchiolitis obliterans in the group with bacterial infection were significantly higher than those of without bacterial infection group ( P<0.05). Conclusion:For children under 2 years old age with severe adenovirus pneumonia, there are prolonged high fever and extensive pulmonary lesions.We should be highly alert to the combination of bacterial infection and timely anti-infection therapy.Children with severe adenovirus pneumonia with bacterial infection have severe clinical manifestations and many complications with respiratory failure, hemophagocytic lymphohistiocytosis, and bronchiolitis obliterans.
6.Deep learning reconstruction algorithm in improving portal vein CT image quality
Le CAO ; Xiang LIU ; Yannan CHENG ; Hui HAO ; Junjun LI ; Jian YANG
Journal of Xi'an Jiaotong University(Medical Sciences) 2022;43(6):912-917
【Objective】 To explore the value of deep learning reconstruction algorithm (DLIR) in improving image quality of portal vein. 【Methods】 We retrospectively enrolled 32 patients who underwent double-phasic enhanced abdominal CT scanning. Images at the portal venous phase were reconstructed using the 50% adaptive statistical iterative reconstruction (ASIR-V), DLIR at medium (DLIR-M) and high strength (DLIR-H). The CT value and image noise (standard deviation) of the main portal vein, the right portal vein branch, the left portal vein branch, and the paravertebral muscle were measured, and the contrast-noise-ratio (CNR) for vessels were calculated. Moreover, the edge-rising-slope (ERS) of the main portal vein edge was measured to evaluate image spatial resolution. The overall image noise, image contrast, and portal vein branch display were evaluated using a 5-point grading scale and image artifacts using a 4-point grading scare by two experienced radiologists. In addition, we calculated the display rate of small branches of the portal vein in the three reconstruction algorithms. 【Results】 Image noise of the DLIR images in the main portal vein, right branch and left branch was significantly lower than that of ASIR-V 50% images, of which the DLIR-H images had the lowest noise and highest CNR. The ERS of the DLIR images in the main portal vein was significantly higher than that of the ASIR-V 50% images. For qualitative analyses, the DLIR images were significantly better than the ASIR-V 50% ones (P<0.01). In addition, the display rates of small branches of the portal vein in DLIR images were (DLIR-M: 93.75%; DLIR-H: 100%), significantly higher than that of ASIR-V 50% (68.75%). 【Conclusion】 Compared with ASIR-V 50% images, DLIR images can significantly reduce the image noise and improve the spatial resolution of the portal vein and the display rate of small branches of the portal vein.
7.Dosimetric verification of stereotactic body radiotherapy treatment plan via ArcCHECK-3DVH system.
Shulin CHENG ; Dongyong SHAN ; Ke CAO ; Shizhen BIN ; Junjun ZHANG ; Tian TANG
Journal of Central South University(Medical Sciences) 2021;46(5):475-480
OBJECTIVES:
To study the feasibility of ArcCHECK-3DVH system in dosimetric verification for stereotactic body radiaotherapy (SBRT) with flattening filter free (FFF) model.
METHODS:
SBRT treatment plans for 57 patients were introduced into ArcCHECK phantom and recalculated. The calculated dose distribution of treatment planning system and the measured dose distribution of ArcCHECK phantom were compared by γ analysis. Then the 3 dimensional dose distribution of target and organs at risk was reconstructed by 3DVH software. The reconstructed dose and calculated dose with treatment planning system (TPS) were compared, and the dose volume γ pass rate and deviation of dose volume parameters to the target and organs at risk were quantitatively valuated.
RESULTS:
Based on the threshold criteria (3%, 3 mm, 10%), namely the deviation of measuring points between the planned value and the measured value was less than 3%, and the proportion of points with similar values in the plane or sphere with the center of the point and the radius of 3 mm was 10%, the relative and absolute dose pass rates of SBRT treatment plans in ArcCHECK system via γ analysis were greater than 95%. Based on the stricter threshold criteria (2%, 2 mm, 10%), the relative and absolute dose pass rates of SBRT treatment plan in ArcCHECK system via γ analysis were about 93%. In 3DVH dose verification, the γ pass rate of target and organs at risk was exceed 97%, and the deviations in 3DVH of the target and organs at risk were less than ±5%.
CONCLUSIONS
The ArcCHECK-3DVH system in dose verification can provide more comprehensive dose distribution information to reasonably evaluate the SBRT plan, with more significance for guiding clinical treatment.
Humans
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Phantoms, Imaging
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Quality Assurance, Health Care
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Radiometry
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Radiosurgery
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Radiotherapy Dosage
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Radiotherapy Planning, Computer-Assisted
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Radiotherapy, Intensity-Modulated
8. Incidence of chronic obstructive pulmonary disease and pneumoconiosis in different occupational positions among populations from jinchang cohort
Jianing CAO ; Desheng ZHANG ; Junjun HUANG ; Nan JIANG ; Haiyan LI ; Kaifang BAO ; Jie DING ; Xiaoliang CHEN ; Li MA ; Xiaobin HU ; Juansheng LI ; Xiaowei REN ; Ning CHENG ; Yana BAI
Chinese Journal of Industrial Hygiene and Occupational Diseases 2019;37(9):650-655
Objective:
To investigate the incidence and rank of chronic obstructive pulmonary disease and pneumoconiosis to the workers in different occupational positions in Jinchang Cohort.
Methods:
In January 2014, a cohort of follow-up population in jinchang city was taken as the research object, 17843 individuals among follow-up populations in Jinchang Cohort Study, removed the individuals with chronic obstructive pulmonary disease and pneumoconiosis before 2013, and counted the new incidence individuals diagnosed by the A-Class hospital in Grade III in Jinchang City, Gansu Province, as the investigation objects to investigate the incidence rate & rank of chronic obstructive pulmonary disease and pneumoconiosis. The statistical significance was tested by chi-square test.
Results:
The 2-year incidence rate of Chronic Obstructive Pulmonary Disease and Pneumoconiosis in the population of Jinchang Cohort Study were 11.60‰, 13.51‰ for male and 8.46‰ for female. the ranks of 2-year incidence rates of chronic bronchitis, emphysema, pneumoconiosis and other phenotypes of chronic obstructive pulmonary disease were 7.06‰、3.42‰、0.84‰、0.34‰, respectively. Incidence rate of chronic bronchitis among administrators and executive staffs were 10.45‰; incidence rate of chronic bronchitis among service staffs were 10.45‰; incidence rate of pneumoconiosis among mining staffs were 3.44‰.
Conclusion
The first incidence rank of chronic obstructive pulmonary disease and pneumoconiosis in Jinchang cohort is chronic bronchitis, and the risk factors are smoking and occupational exposure.
9.Dosimetric verification of flattening filter free model based on TrueBeam accelerator using ArcCheck system.
Yuxing ZHU ; Dongyong SHAN ; Shizhen BIN ; Junjun ZHANG ; Ji ZHANG ; Xiaoming LIU ; Ke CAO ; Shulin CHENG
Journal of Central South University(Medical Sciences) 2018;43(8):864-868
To study the feasibility of ArcCheck verification system in dosimetric verification for stereotactic radiotherapy (SRT) the stereotactic radiotherapy (SRT) with flattening filter free (FFF) model.
Methods: A total of 76 cases under SRT treatment plans were introduced into ArcCheck phantom and recalculated. Threshold criteria was set as (3%, 3 mm, 10%) or (2%, 2 mm, 10%). The calculated dose distribution and the measured dose distribution of ArcCheck phantom were compared by means of distance to agree (DTA) and Gamma analysis method respectively.
Results: Based on the threshold criteria (3%, 3 mm, 10%), the relative and absolute mean pass rates of SRT treatment plans by DTA and Gamma analysis were greater than 95%. Based on the threshold criteria (2%, 2 mm, 10%), the relative and absolute mean pass rates of SRT treatment plan by DTA and Gamma analysis were about 90%. The dose pass rate of Gamma analysis method was slightly higher than that of DTA analysis method (P<0.001).
Conclusion: The ArcCheck verification system is a rapid and accurate method for SRT dose verification, and discrepancies are found in different analysis methods.
Feasibility Studies
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Humans
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Phantoms, Imaging
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Radiosurgery
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methods
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Radiotherapy Dosage
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Radiotherapy Planning, Computer-Assisted
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Radiotherapy, Intensity-Modulated
10.Biomechanical study of lumbosacral spine fixation with double pedicle crew system by anterolateral approach in one stage
Yin YANG ; Xijing HE ; Junjun CAO ; Yanping ZHANG ; Hua GUO ; Lisheng WANG ; Jiantao LIU
Chinese Journal of Orthopaedics 2018;38(22):1374-1383
Objective To conduct the biomechanical evaluation of the effect of the new operative method,one stageanterior debridement and fusion combined withtitanium cage and dual screw-rod anterior instrumentation inter-fixation on the reconstruction of lumbosacral spine stability and provide biomechanical support for its further promotion in clinical practice.Methods Fifteen lumbosacral spine specimens were obtained from the department of anatomy,Xi'an Jiaotong University Health Science Center.Fracture,deformity and osteoporosis were removed by CT and bone density examination.The remaining specimens were randomly divided into intact group,anterior fixation group and posterior fixation group.L5 vertebral body and adjacent intervertebraldisc subtotal resection were performed on all specimens in the anterior fixation group and the posterior fixation group.The specimens in the anterior fixation group were fixed through titanium cage and dual screw-rod from front approach and the specimens inthe posterior group were fixed by dual screw-rod from posterior approach.Specimens in the intact group were not treated.All specimens were examined by X-ray and thin-slice CT after surgery to determine whether implant placement was appropriate andwhether there was spinal cord compression or not.Three groups of lumbosacral spine specimens were subjected to mechanical testsunder the conditions of flexion and extension,lateral bending,axial torsion and axial compression to evaluate the mechanical effect of anterior dual screw-rod system combined with titanium cage on the fixation of lumbosacral spine.Results All lumbosacralspine specimens were free of fractures,deformities,osteoporosis and other diseases.Postoperative imaging examination showed thatthe implant was in normal position and no adverse phenomena such as pedicle screw insertion into the spinal canal and spinalcord compression were observed.Mechanical test results in vitro showed that the load required for maximum loading displacement (5 mm) or rotation angle (5°) of the specimens in the intact group was less than that of the specimens in anterior and posterior fixation group in flexion,lateral bending and axial compression and torsion direction (Fflexion=1335.989,Pflexion=0.000;Fextenxion=166.688,Pextenxion=0.000;Fleft latebending=258.872,Pleft lateral bending=0.000;Fright lateral bending=335.766,Pright lateral bending=0.000;Faxial compression=481.444,Paxial compression =0.000;Fleft rotation=21.682,Pleft totation=0.000;Fright rolation=34.990,Pright rotation=0.000).When the maximum loading displacement (5 mm) was reached,the load required for the specimens in anterior fixation group was significantly greater than that for specimens in posterior fixation groupin the direction of flexion,left and right lateral bending and axial compression (Pflexion=0.000;Pleft lateral bending=0.006;Pright lateral bending=0.016;Paxial compression=0.000).However,the load required to reach the maximum loading displacement (5 mm) in the anterior fixation group in the direction of extension was significantly lower than that in the posterior fixation group (P=0.000).When the maximum load angle (5°) was reached intorsion direction,the required load of the specimens in both anterior and posterior fixation groups was similar (Pleft rotation=0.820;Pright rotation=0.259).Conclusion The anterior fixation of lumbosacral spine specimens with titanium cage combined with dualscrew rod can provide better immediate stability and its stability in flexion,lateral bending and axial compression is better than that of back double nailing rodfixed.

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