Objective The stress distribution of the lumbar spine L1-5,fibrous rings and nucleus pulposus of the patient in mid-phase of single-leg support under slow-walking gait was studied,to determine the optimal correction angle of the osteotomy block in curved periacetabular osteotomy(CPO),and provide an individualized plan for clinical surgery.Methods The femur-pelvis-lumbar spine DICOM data of a patient and a healthy volunteer were obtained using CT scanning to construct a three-dimensional finite element model.The cortical bone,cancellous bone,and cartilages were delineated using the modeling software,and the model was analyzed by finite element method using simulation software.The patient's lateral center edge angle(LCEA)and anterior center edge angle(ACEA)were 15°,and 16 different postoperative models(LCEA=15°,25°,35°,45° and ACEA=15°,25°,35°,45°)were obtained by computer simulation of the surgical osteotomy process.The stress differences in the regions of interest of the model were compared and analyzed,which were also compared with those of patient before surgery and the healthy volunteer,so as to obtain the optimal surgical plan.Results The stresses applied to the lumbar spine decreased with increasing LCEA and ACEA angles,with the lowest stresses applied to the lumbar cones,nucleus pulposus,and annulus fibrosus in the LCEA=35°,ACEA=35° models;then,the stresses applied increased with increasing angles.Conclusions The optimal correction angle for LCEA and ACEA can be obtained using the finite element method,and this method is of great significance to improve the accuracy and efficiency of CPO for different patients.

In order to investigate the mechanical response of lumbar vertebrae during gait cycle in adolescents with idiopathic scoliosis (AIS), the present study was based on computed tomography (CT) data of AIS patients to construct model of the left support phase (ML) and model of the right support phase (MR), respectively. Firstly, material properties, boundary conditions and load loading were set to simulate the lumbar vertebra-pelvis model. Then, the difference of stress and displacement in the lumbar spine between ML and MR was compared based on the stress and displacement cloud map. The results showed that in ML, the lumbar stress was mostly distributed on the convex side, while in MR, it was mostly distributed on the concave side. The stress of the two types of stress mainly gathered near the vertebral arch plate, and the stress of the vertebral arch plate was transmitted to the vertebral body through the pedicle with the progress of gait. The average stress of the intervertebral tissue in MR was greater than that in ML, and the difference of stress on the convex and convex side was greater. The displacement of lumbar vertebrae in ML decreased gradually from L1 to L5. The opposite is true in MR. In conclusion, this study can accurately quantify the stress on the lumbar spine during gait, and may provide guidance for brace design and clinical decision making.
Humans ; Lumbar Vertebrae/diagnostic imaging* ; Scoliosis/diagnostic imaging* ; Adolescent ; Gait/physiology* ; Biomechanical Phenomena ; Tomography, X-Ray Computed ; Stress, Mechanical ; Female ; Male

Objective The stress distribution of the lumbar spine L1-5,fibrous rings and nucleus pulposus of the patient in mid-phase of single-leg support under slow-walking gait was studied,to determine the optimal correction angle of the osteotomy block in curved periacetabular osteotomy(CPO),and provide an individualized plan for clinical surgery.Methods The femur-pelvis-lumbar spine DICOM data of a patient and a healthy volunteer were obtained using CT scanning to construct a three-dimensional finite element model.The cortical bone,cancellous bone,and cartilages were delineated using the modeling software,and the model was analyzed by finite element method using simulation software.The patient's lateral center edge angle(LCEA)and anterior center edge angle(ACEA)were 15°,and 16 different postoperative models(LCEA=15°,25°,35°,45° and ACEA=15°,25°,35°,45°)were obtained by computer simulation of the surgical osteotomy process.The stress differences in the regions of interest of the model were compared and analyzed,which were also compared with those of patient before surgery and the healthy volunteer,so as to obtain the optimal surgical plan.Results The stresses applied to the lumbar spine decreased with increasing LCEA and ACEA angles,with the lowest stresses applied to the lumbar cones,nucleus pulposus,and annulus fibrosus in the LCEA=35°,ACEA=35° models;then,the stresses applied increased with increasing angles.Conclusions The optimal correction angle for LCEA and ACEA can be obtained using the finite element method,and this method is of great significance to improve the accuracy and efficiency of CPO for different patients.

Objective To establish preoperative and postoperative femoral-pelvic-lumbar spine models of patients with developmental dysplasia of the hip(DDH)and healthy volunteers and to study the biomechanical effects of curved periacetabular osteotomy on the lumbar spine.Methods Preoperative and postoperative femoral-pelvic-lumbar spine DICOM data from four patients with DDH and one healthy volunteer were acquired using CT scanning technology,and a three-dimensional finite element model was constructed.The offset method was used to divide the cortical and cancellous bones in Geomagic and the lumbar cartilage,sacroiliac joint,pubic symphysis,and other cartilages were added to SolidWorks.The model was analyzed using ANSYS for finite element analysis,and the gait was the mid-stage of single-leg support during slow walking.The biomechanical changes in the lumbar spine of patients with DDH before and after surgery were analyzed and compared,and the biomechanical data of the lumbar spine of patients after surgery were compared with those of healthy volunteers.Results The femoral-pelvic-lumbar spine models of four patients and a healthy volunteer were established.The results obtained by the established models under each working condition were within the range of the referenced literature,and the validity of the models was proved.The postoperative stresses on the lumbar spine,femoral neck,annulus fibrosus,and nucleus pulposus were much smaller than those of the patients in the preoperative state,and the postoperative stresses on the lumbar spine,femoral neck,annulus fibrosus,and nucleus pulposus of the patients were similar to those of healthy volunteers.Conclusions Curved periacetabular osteotomy significantly reduced the stresses on the lumbar spine and intervertebral discs.Additionally,the stresses on the annulus fibrosus were more uniform after surgery,which indicated that curved periacetabular osteotomy will adjust patients to a healthy state.This study provides a biomechanical basis for the clinical treatment of DDH and helps optimize surgical plans.

Objective:In this study, we aimed to compare the short-term safety of two digestive tract reconstruction techniques, laparoscopic total abdominal overlap anastomosis and laparoscopic-assisted end-to-side anastomosis, following radical resection of Siewert Type II adenocarcinoma of the esophagogastric junction.Methods:In this retrospective cohort study, we analyzed relevant clinical data of 139 patients who had undergone radical surgery for Siewert Type II esophagogastric junction adenocarcinoma. These included 89 patients treated at the First Affiliated Hospital of Air Force Medical University from November 2021 to July 2023, 36 patients treated at the First Affiliated Hospital of Xi'an Jiaotong University from December 2020 to June 2021, and 14 patients treated at the Yuncheng Central Hospital in Shanxi Province from September 2021 to November 2022. The group consisted of 107 men (77.0%) and 32 women (23.0%) of mean age 62.5±9.3 years. Forty-eight patients underwent laparoscopic total abdominal overlap anastomosis (overlap group), and 91 laparoscopic-assisted end-to-side anastomosis (end-to-side group). Clinical data, surgical information, pathological findings, postoperative recovery, and related complications were compared between the two groups.Results:There were no significant differences in general clinical data between the overlap and end-to-side anastomosis groups (all P>0.05), indicating comparability. There was no significant difference in operation time (267.2±60.1 minutes vs. 262.8±70.6 minutes, t=0.370, P=0.712). However, the intraoperative blood loss in the overlap group (100 [50, 100] mL) was significantly lower compared to the end-to-side group (100[50, 175] mL, Z=2.776, P=0.005). Compared to the end-to-side group, longer distances between the tumor and distal resection margin proximal(1.7±1.0 cm vs. 1.3±0.9 cm, t=2.487, P=0.014) and the tumor and distal resection margin (9.5±2.9 cm vs. 7.9±3.5 cm, t=2.667, P=0.009) were achieved in the overlap group. Compared with the end-to-side group, the overlap group achieved significantly earlier postoperative ambulation (1.0 [1.0, 2.0] days vs. 2.0 [1.0, 3.0] days, Z=3.117, P=0.002), earlier time to first drink (4.7±2.6 days vs. 6.2±3.0 days, t=2.851, P=0.005), and earlier time to first meal (6.0±2.7 days vs. 7.1±3.0 days, t=2.170, P=0.032). However, the hospitalization costs were higher in the overlap group (113, 105.5±37, 766.3) yuan vs. (97, 250.2±27, 746.9) yuan; this difference is significant ( t=2.818, P=0.006). There were no significant differences between the two groups in postoperative hospital stay, total number of lymph nodes cleared, or time to first postoperative flatus (all P>0.05). The incidence of surgery-related complications was 22.9%(11/48) in the overlap group and 19.8% (18/91) in the end-to-side group; this difference is not significant (χ2=0.187, P=0.831). Further comparison of complications using the Clavien-Dindo classification also showed no significant differences ( Z=0.406, P=0.685). Conclusions:Both laparoscopic total abdominal overlap anastomosis and laparoscopic-assisted end-to-side anastomosis are feasible for radical surgery for Siewert Type II esophagogastric junction adenocarcinoma. Laparoscopic total abdominal overlap anastomosis achieves longer proximal and distal resection margins and better postoperative recovery; however, end-to-side anastomosis is more cost-effective.

Objective:In this study, we aimed to compare the short-term safety of two digestive tract reconstruction techniques, laparoscopic total abdominal overlap anastomosis and laparoscopic-assisted end-to-side anastomosis, following radical resection of Siewert Type II adenocarcinoma of the esophagogastric junction.Methods:In this retrospective cohort study, we analyzed relevant clinical data of 139 patients who had undergone radical surgery for Siewert Type II esophagogastric junction adenocarcinoma. These included 89 patients treated at the First Affiliated Hospital of Air Force Medical University from November 2021 to July 2023, 36 patients treated at the First Affiliated Hospital of Xi'an Jiaotong University from December 2020 to June 2021, and 14 patients treated at the Yuncheng Central Hospital in Shanxi Province from September 2021 to November 2022. The group consisted of 107 men (77.0%) and 32 women (23.0%) of mean age 62.5±9.3 years. Forty-eight patients underwent laparoscopic total abdominal overlap anastomosis (overlap group), and 91 laparoscopic-assisted end-to-side anastomosis (end-to-side group). Clinical data, surgical information, pathological findings, postoperative recovery, and related complications were compared between the two groups.Results:There were no significant differences in general clinical data between the overlap and end-to-side anastomosis groups (all P>0.05), indicating comparability. There was no significant difference in operation time (267.2±60.1 minutes vs. 262.8±70.6 minutes, t=0.370, P=0.712). However, the intraoperative blood loss in the overlap group (100 [50, 100] mL) was significantly lower compared to the end-to-side group (100[50, 175] mL, Z=2.776, P=0.005). Compared to the end-to-side group, longer distances between the tumor and distal resection margin proximal(1.7±1.0 cm vs. 1.3±0.9 cm, t=2.487, P=0.014) and the tumor and distal resection margin (9.5±2.9 cm vs. 7.9±3.5 cm, t=2.667, P=0.009) were achieved in the overlap group. Compared with the end-to-side group, the overlap group achieved significantly earlier postoperative ambulation (1.0 [1.0, 2.0] days vs. 2.0 [1.0, 3.0] days, Z=3.117, P=0.002), earlier time to first drink (4.7±2.6 days vs. 6.2±3.0 days, t=2.851, P=0.005), and earlier time to first meal (6.0±2.7 days vs. 7.1±3.0 days, t=2.170, P=0.032). However, the hospitalization costs were higher in the overlap group (113, 105.5±37, 766.3) yuan vs. (97, 250.2±27, 746.9) yuan; this difference is significant ( t=2.818, P=0.006). There were no significant differences between the two groups in postoperative hospital stay, total number of lymph nodes cleared, or time to first postoperative flatus (all P>0.05). The incidence of surgery-related complications was 22.9%(11/48) in the overlap group and 19.8% (18/91) in the end-to-side group; this difference is not significant (χ2=0.187, P=0.831). Further comparison of complications using the Clavien-Dindo classification also showed no significant differences ( Z=0.406, P=0.685). Conclusions:Both laparoscopic total abdominal overlap anastomosis and laparoscopic-assisted end-to-side anastomosis are feasible for radical surgery for Siewert Type II esophagogastric junction adenocarcinoma. Laparoscopic total abdominal overlap anastomosis achieves longer proximal and distal resection margins and better postoperative recovery; however, end-to-side anastomosis is more cost-effective.

OBJECTIVE: To establish a finite element model of the knee joint based on coronal plane alignment of the knee (CPAK) typing method, and analyze the biomechanical characteristics of different types of knee joints. METHODS: The finite element models of the knee joint were established based on CT scan data of 6 healthy volunteers. There were 5 males and 1 female with an average age of 24.2 years (range, 23-25 years). There were 3 left knees and 3 right knees. According to the CPAK typing method, the knees were rated as types Ⅰ to Ⅵ. Under the same material properties, boundary conditions, and axial loading, biomechanical simulations were performed on the finite element model of the knee joint. Based on the Von Mises stress nephogram and displacement nephogram, the peak stresses of the meniscus, femoral cartilage, and tibial cartilage, and the displacement of the meniscus were compared among different types of knee joints. RESULTS: The constructed finite element model of the knee joint was verified to be effective, and the stress and displacement results were consistent with previous literature. Under the axial load of 1 000 N, the stress nephogram showed that the stress distribution of the medial and lateral meniscus and tibial cartilage of CPAK type Ⅲ knee joint was the most uneven. The peak stresses of the lateral meniscus and tibial cartilage were 9.969 6 MPa and 2.602 7 MPa, which were 173% and 165% of the medial side, respectively. The difference of peak stress between the medial and lateral femoral cartilage was the largest in type Ⅳ knee joint, and the medial was 221% of the lateral. The displacement nephogram showed that the displacement of the medial meniscus was greater than that of the lateral meniscus except for types Ⅲ and Ⅵ knee joints. The difference between medial and lateral meniscus displacement of type Ⅲ knee joint was the largest, the lateral was 170% of the medial. CONCLUSION In the same type of joint line obliquity (JLO), the medial and lateral stress distribution of the knee was more uniform in varus and neutral positions than in valgus position. At the same time, the distal vertex of JLO subgroup can help to reduce the uneven medial and lateral stress distribution of varus knee, but increase the uneven distribution of valgus knee.
Humans ; Finite Element Analysis ; Knee Joint/diagnostic imaging* ; Female ; Biomechanical Phenomena ; Adult ; Male ; Young Adult ; Stress, Mechanical ; Weight-Bearing/physiology* ; Computer Simulation ; Tomography, X-Ray Computed/methods* ; Cartilage, Articular/physiology* ; Range of Motion, Articular ; Menisci, Tibial/anatomy & histology* ; Tibia/anatomy & histology* ; Meniscus/diagnostic imaging* ; Femur/diagnostic imaging* ; Models, Biological

Sacral neuromodulation (SNM) procedure has become a new therapy to treat chronic constipation and fecal incontinence. The surgical procedure is easy and safe. It has a small incision compared with traditional surgery and is mainly used in patients whose traditional treatment was unsuccessful. Chronic constipation is one of the most common digestive symptoms. The quality of life in patients with severe constipation has decreased greatly. Although the incidence of fecal incontinence in China is not as high as that of constipation, it also seriously affects the life of the patients, resulting in a decline in the quality of life. Although the mechanism of SNM is uncertain, with more studies conducted, understanding has become more profound, and the curative effect has been recognized. SNM can improve the symptoms and the quality of life. Many studies have reported SNM treatment. Furthermore, some trials on SNM have been conducted. It is used after colorectal resections to promote symptoms of bowel dysfunction. However, few studies reported regarding SNM for constipation and fecal incontinence in China, and knowledge regarding SNM is limited. In this article, we will mainly discuss SNM in the treatment of chronic constipation and fecal incontinence, and its research progress on the mechanism and method, surgical procedure, effectiveness, complications, postoperative contraindications, and the population who need to pay attention, in order to provide reference for the treatment of SNM in China.

OBJECTIVETo assess the efficacy of sacral neuromodulation (SNM) in patients with intractable constipation.

METHODSA total of 7 patients with intractable constipation were treated with pereutaneous test stimulation of the S3 nerve root and were assessed by sacral never stimulation system in our department from January 2013 to January 2014. Four of these 7 patients received operation for constipation before. The efficacy was assessed by bowel habit diary, clinic constipation scores, subjective questionnaire and clinical signs.

RESULTSThe constipation symptoms were improved significantly in all the 7 patients. The frequency and volume of defecation per week were increased obviously, and the average urine was increased. Six patients underwent permanent implantation of the SNS system. After a median 4 months follow-up, the defecation frequency increased from 0.6 ± 0.5 to 8.0 ± 2.5 per week (P<0.01), and the defecation time decreased from (22.9 ± 11.5) to (3.7 ± 0.8) min (P<0.01). The Cleveland clinic constipation score decreased from 24.6 ± 4.2 to 9.0 ± 0.9 (P<0.01), and the visual analogue scale(VAS) score increased from 8.1 ± 0.9 to 82.5 ± 5.2 (P<0.01).

CONCLUSIONSNM is a clinically efficacious, minimally invasive and safe new technique, which offers an alternative treatment for the patients with intractable constipation resistant to conservative treatment, especially for the patients refractory to traditional operations.

Objective To assess the efficacy of sacral neuromodulation (SNM) in patients with intractable constipation. Methods A total of 7 patients with intractable constipation were treated with pereutaneous test stimulation of the S3 nerve root and were assessed by sacral never stimulation system in our department from January 2013 to January 2014. Four of these 7 patients received operation for constipation before. The efficacy was assessed by bowel habit diary, clinic constipation scores, subjective questionnaire and clinical signs. Results The constipation symptoms were improved significantly in all the 7 patients. The frequency and volume of defecation per week were increased obviously, and the average urine was increased. Six patients underwent permanent implantation of the SNS system. After a median 4 months follow-up, the defecation frequency increased from 0.6 ±0.5 to 8.0 ±2.5 per week (P<0.01), and the defecation time decreased from (22.9 ±11.5) to (3.7 ±0.8) min (P<0.01). The Cleveland clinic constipation score decreased from 24.6±4.2 to 9.0±0.9 (P<0.01), and the visual analogue scale(VAS) score increased from 8.1±0.9 to 82.5±5.2(P<0.01). Conclusion SNM is a clinically efficacious, minimally invasive and safe new technique, which offers an alternative treatment for the patients with intractable constipation resistant to conservative treatment , especially for the patients refractory to traditional operations.