Objective To study the effect of wall thickness on the accuracy(trueness and precision)of 3D printed models.Methods The 3D scanning data of the standard gypsum dental arch model was imported into Exocad software.And four sets of models were de-signed,including horseshoe shaped solid model and horseshoe shaped hollow models with different wall thicknesses(2 mm,3 mm,4 mm).On the first and seventh day after printing,the 3D scanning data of resin models were imported into Geomagic software.Deviation analysis were performed on 3D printed models for the root mean square(root mean square,RMS).Results The trueness range of the four groups of printed models on the first day was(34.63±4.17)μm to(45.26±6.50)μm,there was no statistical difference.The pre-cision range was(30.25±10.18)μm to(47.65±14.77)μm,and the precision of the solid group was lower than the other three groups(P＜0.05).The trueness range of the four groups of printing models on the 7th day was(49.00±9.11)μm to(69.25±9.70)μm.The trueness of the 2 mm wall thickness group was lower than that of the solid group and the 4 mum wall thickness group(P＜0.05).Con-clusion The accuracy of printing models with different wall thicknesses was within the clinical acceptance range.There was no statisti-cally significant difference in the trueness values of the four groups of printing models on the first day.The precision value of the solid group was the lowest.On the 7th day,the trueness of the wall thickness of 2 mm group was lower than that of the solid group and the 4 mum wall thickness group.

Objective:To compare the impact of the AlignRT-based optical guidance method with the traditional marker line method on the accuracy of positioning, and explore the effect of patient′s different thoracic characteristic parameters on the precision of optical guidance positioning.Methods:A total of sixty breast cancer patients who received post breast-conserving radiotherapy at Anhui Cancer Hospital from July 2022 to September 2023 were retrospectively selected. Then these patients were equally divided into traditional cross hairs set-up (marker line group) and surface-guided set-up (SGRT group). The cone-beam CT scanning results were used as the gold standard, the three-dimensional set-up errors and the CTV-PTV target area external radiotherapy boundaries of two groups were studied comparatively. Multiple patient′s thoracic characteristic parameters were defined and the correction between each parameter and set-up error of SGRT was analyzed.Results:The mean value of three-dimensional set-up errors in the SGRT group and the marker line group was within 0.2 cm and 0.5 cm, respectively. The differences in three-dimensional set-up errors and total displacements between two groups were statistically significant ( z=-2.93, -3.21, -2.59, -4.76, P<0.05). The SGRT group reduced the CTV-PTV boundary from 0.5 cm of conventional marker line group to 0.3 cm. The thoracic aspect ratio H/W, the affected side pinch angle α1, and the healthy side pinch angle α2 were positively correlated with the x-direction posing error ( r=0.49, 0.59, 0.71, P<0.05); whereas, the affected side and the healthy side mammary gland heights D1 and D2 were negatively correlated with the z-direction posing error ( r=-0.46, -0.49, P<0.05). Conclusions:For breast-conserving postoperative radiotherapy patients, SGRT can obtain a more accurate radiotherapy set-up than the traditional marker line method, and can effectively reduce the target area externally expanded range. Meanwhile, the monitoring accuracy of SGRT is affected by the patient′s thoracic characteristic parameters, and clinical attention should be paid to breast-conserving radiotherapy patients with thick body shape, narrow body width, and small breast glands.

Objective To study the effect of wall thickness on the accuracy(trueness and precision)of 3D printed models.Methods The 3D scanning data of the standard gypsum dental arch model was imported into Exocad software.And four sets of models were de-signed,including horseshoe shaped solid model and horseshoe shaped hollow models with different wall thicknesses(2 mm,3 mm,4 mm).On the first and seventh day after printing,the 3D scanning data of resin models were imported into Geomagic software.Deviation analysis were performed on 3D printed models for the root mean square(root mean square,RMS).Results The trueness range of the four groups of printed models on the first day was(34.63±4.17)μm to(45.26±6.50)μm,there was no statistical difference.The pre-cision range was(30.25±10.18)μm to(47.65±14.77)μm,and the precision of the solid group was lower than the other three groups(P＜0.05).The trueness range of the four groups of printing models on the 7th day was(49.00±9.11)μm to(69.25±9.70)μm.The trueness of the 2 mm wall thickness group was lower than that of the solid group and the 4 mum wall thickness group(P＜0.05).Con-clusion The accuracy of printing models with different wall thicknesses was within the clinical acceptance range.There was no statisti-cally significant difference in the trueness values of the four groups of printing models on the first day.The precision value of the solid group was the lowest.On the 7th day,the trueness of the wall thickness of 2 mm group was lower than that of the solid group and the 4 mum wall thickness group.

Objective:To compare the impact of the AlignRT-based optical guidance method with the traditional marker line method on the accuracy of positioning, and explore the effect of patient′s different thoracic characteristic parameters on the precision of optical guidance positioning.Methods:A total of sixty breast cancer patients who received post breast-conserving radiotherapy at Anhui Cancer Hospital from July 2022 to September 2023 were retrospectively selected. Then these patients were equally divided into traditional cross hairs set-up (marker line group) and surface-guided set-up (SGRT group). The cone-beam CT scanning results were used as the gold standard, the three-dimensional set-up errors and the CTV-PTV target area external radiotherapy boundaries of two groups were studied comparatively. Multiple patient′s thoracic characteristic parameters were defined and the correction between each parameter and set-up error of SGRT was analyzed.Results:The mean value of three-dimensional set-up errors in the SGRT group and the marker line group was within 0.2 cm and 0.5 cm, respectively. The differences in three-dimensional set-up errors and total displacements between two groups were statistically significant ( z=-2.93, -3.21, -2.59, -4.76, P<0.05). The SGRT group reduced the CTV-PTV boundary from 0.5 cm of conventional marker line group to 0.3 cm. The thoracic aspect ratio H/W, the affected side pinch angle α1, and the healthy side pinch angle α2 were positively correlated with the x-direction posing error ( r=0.49, 0.59, 0.71, P<0.05); whereas, the affected side and the healthy side mammary gland heights D1 and D2 were negatively correlated with the z-direction posing error ( r=-0.46, -0.49, P<0.05). Conclusions:For breast-conserving postoperative radiotherapy patients, SGRT can obtain a more accurate radiotherapy set-up than the traditional marker line method, and can effectively reduce the target area externally expanded range. Meanwhile, the monitoring accuracy of SGRT is affected by the patient′s thoracic characteristic parameters, and clinical attention should be paid to breast-conserving radiotherapy patients with thick body shape, narrow body width, and small breast glands.

Objective:To investigate the clinical effect of proper management of inferior pancreaticoduodenal artery (IPDA) in laparoscopic pancreaticoduodenectomy (LPD).Methods:This is a retrospective case series study. The clinical and pathological data of 70 patients who received LPD due to pancreatic head tumors, periampullary tumors, or distal common bile duct tumors in the Pancreatic Center of the Second Clinical College of Guangzhou University of Chinese Medicine from January to December 2022 were retrospectively collected. There were 47 males(67.1%) and 23 females(32.9%),aged (59.9±12.8)years(range:13 to 87 years).The procedure of IPDA exposure was as follows:a middle approach was utilized to expose the right half of superior mesenteric artery(SMA) and its right branches between the SMA and superior mesenteric vein(SMV) in superior colonic region. In the subcolonic region,SMA trunk exposure via dissection along the jejunal artery from feet to head and identification the association between IPDA and jejunal artery were prior to IPDA root ligation and dissection. The safety and efficacy of intraoperative IPDA handling were assessed based on surgical videos. Follow-up was carried out in outpatient clinic or by telephone, and outpatient follow-up was conducted once every 1 to 3 months after surgery.Results:The percentage of total LPD was 98.6%(69/70),with all patients achieving R0 resection. Nine cases(12.9%) were involved in combined vascular resection and reconstruction,with 1 case (1.4%) requiring additional upper abdominal incision for vascular and gastrointestinal reconstruction,while the remaining eight cases (11.4%) were completed laparoscopically. The operative time was (432.7±115.4)minutes(range:282 to 727 minutes), and the blood loss was (140.0±125.7)ml(range:20 to 800 ml). Only two patients(2.9%) received fresh frozen plasma transfusion,with an average volume of 650 ml. Reliable ligation and safe handling of the IPDA were achieved in 91.4%(64/70) of cases, with 8.6%(6/70) suffering from IPDA injury-related bleeding. No one was converted to opened surgery. Pathologically,the mean tumor size was (3.3±1.6)cm (range:1 to 7 cm),and the mean number of harvested lymph nodes was 17.0±7.3(range:0 to 46). Lymph node metastasis was observed in 13 cases (18.6%). Five cases (13.2%) developed grade B pancreatic fistula,while no grade C pancreatic fistula occurred. Other complications included bile leakage in one case(1.4%),delayed gastric emptying in two cases(2.9%), lymphatic leakage in 2 cases(2.9%),intra-abdominal infection in 9 cases(12.9%),and fat liquefaction of surgical incision in 1 case(1.4%). Two cases(2.9%) experienced postoperative intra-abdominal bleeding,one due to mesangial bleeding of lesser curvature of the stomach and the other due to oozing from the hepatic arterial sheath. These bleeding events were not concerned with IPDA. The average length of postoperative hospital stay was (15.2±4.6)days(range:9 to 28 days).Conclusion:Proper intraoperative management of IPDA in LPD might reduce IPDA-related bleeding during and after surgery and improve the safety of LPD.

Total hip arthroplasty(THA)is an effective treatment for elderly femoral neck fractures,mid-to late-stage femoral head necrosis,and end-stage hip osteoarthritis.However,serious complications such as aseptic loosening of the prosthesis,peripheral fractures,and dislocation of the prosthesis still exist following THA,which makes the selection of the appropriate hip prosthesis type and placement position before THA an important challenge for surgeons.Currently,the commonly used preoperative planning methods for THA mainly rely on static images from two-dimensional(2D)X-ray or three-dimensional(3D)computed tomography(CT),which fail to adequately consider the hip joint in weight-bearing as well as motion,lumbar-hip joint changes,and prosthetic impingement during motion.Recently,the dual fluoroscopic imaging system,as a new in-vivo,dynamic radiological imaging technology,provides comprehensive and accurate dynamic 3D data for THA preoperative planning.However,the technical process and expert consensus on preoperative 3D planning of THA using a dual fluoroscopic imaging system have not yet been established,which affects the promotion and application of this technology.In light of the above,national orthopaedic experts and related professional representatives discussed and proposed seven consensus issues,and the'expert recommendation rate'and'strong recommendation rate'were obtained through a questionnaire survey on the recommendations of the participating experts.This consensus aims to provide guidance and reference for the standardised application of preoperative 3D planning of THA using the dual fluoroscopic imaging system.

There are many kinds of zirconia repair materials that have been introduced at home and abroad.Mechanical and aesthetic properties are the important factors for selecting zirconia materials.The process of diagnosis and treatment by dentists and the production by the workers in laboratory affect the final repair effects.To achieve accurate and efficient simulation of dental repair and treatment,effective cooperation between dentists and technicians is required.In this paper,the factors affecting mechanical and aes-thetic properties in the process of material selection,tooth wearing,restoration design and fabrication,concerning zirconia veneer,sin-gle-crown,fixed bridge and edentulous jaw implant fixed repair were discussed and summarized.The common failure reasons were ana-lyzed in order to improve the communication efficiency between dentists and technicians in the process of zirconia repair system and to a-chieve better repair effects.

Objective:To investigate the clinical effect of proper management of inferior pancreaticoduodenal artery (IPDA) in laparoscopic pancreaticoduodenectomy (LPD).Methods:This is a retrospective case series study. The clinical and pathological data of 70 patients who received LPD due to pancreatic head tumors, periampullary tumors, or distal common bile duct tumors in the Pancreatic Center of the Second Clinical College of Guangzhou University of Chinese Medicine from January to December 2022 were retrospectively collected. There were 47 males(67.1%) and 23 females(32.9%),aged (59.9±12.8)years(range:13 to 87 years).The procedure of IPDA exposure was as follows:a middle approach was utilized to expose the right half of superior mesenteric artery(SMA) and its right branches between the SMA and superior mesenteric vein(SMV) in superior colonic region. In the subcolonic region,SMA trunk exposure via dissection along the jejunal artery from feet to head and identification the association between IPDA and jejunal artery were prior to IPDA root ligation and dissection. The safety and efficacy of intraoperative IPDA handling were assessed based on surgical videos. Follow-up was carried out in outpatient clinic or by telephone, and outpatient follow-up was conducted once every 1 to 3 months after surgery.Results:The percentage of total LPD was 98.6%(69/70),with all patients achieving R0 resection. Nine cases(12.9%) were involved in combined vascular resection and reconstruction,with 1 case (1.4%) requiring additional upper abdominal incision for vascular and gastrointestinal reconstruction,while the remaining eight cases (11.4%) were completed laparoscopically. The operative time was (432.7±115.4)minutes(range:282 to 727 minutes), and the blood loss was (140.0±125.7)ml(range:20 to 800 ml). Only two patients(2.9%) received fresh frozen plasma transfusion,with an average volume of 650 ml. Reliable ligation and safe handling of the IPDA were achieved in 91.4%(64/70) of cases, with 8.6%(6/70) suffering from IPDA injury-related bleeding. No one was converted to opened surgery. Pathologically,the mean tumor size was (3.3±1.6)cm (range:1 to 7 cm),and the mean number of harvested lymph nodes was 17.0±7.3(range:0 to 46). Lymph node metastasis was observed in 13 cases (18.6%). Five cases (13.2%) developed grade B pancreatic fistula,while no grade C pancreatic fistula occurred. Other complications included bile leakage in one case(1.4%),delayed gastric emptying in two cases(2.9%), lymphatic leakage in 2 cases(2.9%),intra-abdominal infection in 9 cases(12.9%),and fat liquefaction of surgical incision in 1 case(1.4%). Two cases(2.9%) experienced postoperative intra-abdominal bleeding,one due to mesangial bleeding of lesser curvature of the stomach and the other due to oozing from the hepatic arterial sheath. These bleeding events were not concerned with IPDA. The average length of postoperative hospital stay was (15.2±4.6)days(range:9 to 28 days).Conclusion:Proper intraoperative management of IPDA in LPD might reduce IPDA-related bleeding during and after surgery and improve the safety of LPD.

Total hip arthroplasty(THA)is an effective treatment for elderly femoral neck fractures,mid-to late-stage femoral head necrosis,and end-stage hip osteoarthritis.However,serious complications such as aseptic loosening of the prosthesis,peripheral fractures,and dislocation of the prosthesis still exist following THA,which makes the selection of the appropriate hip prosthesis type and placement position before THA an important challenge for surgeons.Currently,the commonly used preoperative planning methods for THA mainly rely on static images from two-dimensional(2D)X-ray or three-dimensional(3D)computed tomography(CT),which fail to adequately consider the hip joint in weight-bearing as well as motion,lumbar-hip joint changes,and prosthetic impingement during motion.Recently,the dual fluoroscopic imaging system,as a new in-vivo,dynamic radiological imaging technology,provides comprehensive and accurate dynamic 3D data for THA preoperative planning.However,the technical process and expert consensus on preoperative 3D planning of THA using a dual fluoroscopic imaging system have not yet been established,which affects the promotion and application of this technology.In light of the above,national orthopaedic experts and related professional representatives discussed and proposed seven consensus issues,and the'expert recommendation rate'and'strong recommendation rate'were obtained through a questionnaire survey on the recommendations of the participating experts.This consensus aims to provide guidance and reference for the standardised application of preoperative 3D planning of THA using the dual fluoroscopic imaging system.

Humans ; Acetabulum ; Consensus ; Developmental Dysplasia of the Hip/therapy* ; Hip Joint ; Treatment Outcome ; China