BACKGROUND Femoroacetabular impingement(FAI)is a predisposing factor for secondary osteoarthritis of the hip joint.The two extensively described impingement mechanisms of FAI are CAM and Pincer-type.Initially managed ...BACKGROUND Femoroacetabular impingement(FAI)is a predisposing factor for secondary osteoarthritis of the hip joint.The two extensively described impingement mechanisms of FAI are CAM and Pincer-type.Initially managed conservatively,operative intervention should be offered to the persistently symptomatic patient.The measurement of the alpha angle is considered a standard method of assessing the severity of pathology in Cam-type FAI on pre-operative plain radiographs.The radiological correction of the alpha angle has not been previously compared between different surgical approaches.We hypothesize that there is no difference in alpha angle correction between Ganz surgical hip dislocation and the anterior mini-open approach.AIM To compare the magnitude of alpha angle correction achieved by using the Ganz surgical hip dislocation and the anterior mini-open approach.METHODS This is a retrospective study assessing seventy-nine patients identified in a 5-year period.These patients had preoperative radiographic evidence of FAI and underwent surgery by a single surgeon at our institution,a tertiary care center.Patients with missing radiographic documentation,radiographs with insufficient quality which then precluded accurate measurement of the angleα,a diagnosed congenital condition,isolated type II pathology(Pincer),and history of prior surgery were excluded from the study.Either the Ganz surgical hip dislocation or the anterior mini open approach was used.Postoperative radiographic evaluation of the alpha angle between the two surgical methods was done and corrected for age and gender using two-sample t-tests and Chi-square analyses.RESULTS A total of 79 patients met the inclusion and exclusion criteria.Forty-seven males(mean age of 35.3,range 16-53)and 32 females(mean age 36.7,range 16-60)were enrolled.Forty-seven patients underwent the anterior mini-open approach,and 32 underwent the Ganz surgical hip dislocation.There were no significant differences in age between the two surgical groups or in pre-and post-operative alpha angles based on patient gender.The mean pre-operative alpha angle for the Ganz surgical hip dislocation group was 88.0 degrees(SD 12.3)and 99.4 degrees(SD 7.2)for the anterior mini-open group.Mean post-operative angles were 49.9 degrees(SD 4.3)for the Ganz surgical hip dislocation and 43.8(SD 4.3)degrees for the anterior mini-open group.There was a statistically significant difference in patient’s pre-operative and post-operative angles(P=0.000)with both surgical approaches.CONCLUSION Statistically significant decreases in alpha angle were noted for both surgical techniques,with larger decreases seen in the anterior mini-open group.展开更多
AIM:To explore the effect of Alpha angle and Kappa angle before multifocal intraocular lenses(MIOLs)implantation on postoperative visual quality of patients.METHODS:Before and 3mo after cataract surgery,Alpha angle an...AIM:To explore the effect of Alpha angle and Kappa angle before multifocal intraocular lenses(MIOLs)implantation on postoperative visual quality of patients.METHODS:Before and 3mo after cataract surgery,Alpha angle and Kappa angle were collected using IOL Master 700,iTrace,and Pentacam for clinical observation.Postoperative visual quality indicators,including high-order aberrations(HOA),modulation transfer function(MTF)and point spread function(PSF),were collected using iTrace.multiple linear regression analysis was used to analyze the correlation of the Kappa angle and the Alpha angle with age,axial length(AL),anterior chamber depth(ACD),keratometry(K),lens thickness(LT)and corneal white to white distance(WTW).Pearson correlation coefficient was used to analyze the correlation between Alpha angle and Kappa angle;Bland Altman analysis was used to evaluate the consistency of pairwise detection results of three instruments.RESULTS:The Alpha angle was modeled as Alpha=2.230+0.003×age-0.036×AL-0.025×K-0.058×WTW and the Kappa angle was modeled as Kappa=0.685+0.003×age-0.013×K-0.061×WTW.The correlation between the total Alpha angle and Kappa angle of the three instruments was weakly positive(r=0.291,P=0.000).Comparing the measurement of Alpha angle and Kappa angle using three instruments,only IOL Master 700 and iTrace showed good consistency in measuring Kappa angle(P=0.4254).After 3mo of surgery,the Alpha angle and Kappa angle significantly decreased(P=0.011,0.018;P=0.008,0.036).△Kappa=1.136-0.021×AL-0.013×K.Kappa angle could positively predict HOA(β=0.18,P=0.000),MTF(β=0.171,P=0.000),PSF(β=0.088,P=0.000),Alpha angle cannot(P>0.05).CONCLUSION:The patients with older age,flatter K and shorter WTW should be alert to the possibility of larger Alpha angle and Kappa angle.Alpha angle should also consider the factor of AL.When selecting patients with MIOLs implantation,there is no need to consider the Alpha angle.Careful consideration should be given to the Kappa angle,and the preoperative standard of<0.5 mm can refer to△Kappa=1.136-0.021×AL-0.013×K and be appropriately relaxed.展开更多
AIM:To investigate how angles kappa and alpha affect postoperative visual quality in patients with multifocal intraocular lens(mIOLs)implantation.METHODS:Retrospective cases series.A total of 46 patients(46 eyes)who u...AIM:To investigate how angles kappa and alpha affect postoperative visual quality in patients with multifocal intraocular lens(mIOLs)implantation.METHODS:Retrospective cases series.A total of 46 patients(46 eyes)who underwent phacoemulsification were subsumed.The correlation between Preoperative angles kappa and alpha,wave-front aberrations and objective visual quality of cornea,internal,and total eye after surgery were analyzed using iTrace.RESULTS:The magnitude of angle kappa was negatively correlated with internal and total modulation transfer function(MTF)at 3 mm;the magnitude of angle kappa was positively correlated with astigmatism,trefoil,higher-order aberrations(HOAs)of both internal and total eye at 3 mm.The magnitude of angle alpha was negatively correlated with total MTF and total Strehl ratio at 3 mm.The magnitude of angle alpha was positively correlated with corneal coma at 5 mm,internal astigmatism at both 3 mm and 5 mm,and total spherical aberration(SA)at 3 mm.Multivariate linear regression analysis showed that,among candidate independent variables(kappa,alpha,astigmatism,SA,coma,trefoil,and HOAs),astigmatism is the only independent factor for altering corneal MTF at 3 mm and 5 mm;astigmatism and HOAs emerged as independent factors for altering internal MTF at 3 mm and 5 mm,and total MTF at 3 mm;astigmatism,SA and HOAs emerged as independent factors for altering total MTF at 5 mm.CONCLUSION:With greater preoperative angle kappa or angle alpha,patients who accept mIOL implantation tend to have larger internal astigmatism and HOAs,which resulting in poor visual quality,especially those with small pupil size.展开更多
Prediction of roadheader performance plays a significant role in the plan of tunnel construction, which is influenced by different key parameters, including rock strength, discontinuity in rock mass, type and specific...Prediction of roadheader performance plays a significant role in the plan of tunnel construction, which is influenced by different key parameters, including rock strength, discontinuity in rock mass, type and specifications of roadheader machine, and brittleness. The main aim of this study is to build a robust empirical equation based on rock mass properties for the roadheader performance prediction. For achieving the aim, a dataset composed of roadheader performance rate and rock properties is established using the dataset compiled from an underground coal mine located in a remote rugged desert environment some 85 km south of Tabas City in mid east Iran. By using gathered data, the statistical analyses are conducted between rock mass properties and roadheader performance to find whether there is a significant relationship between input variables and roadheader performance. The results show that rock mass properties have a considerable impact on the rate of the roadheader performance. It is demonstrated that the proposed model can accurately predict the roadheader performance as a function of rock mass properties.展开更多
文摘BACKGROUND Femoroacetabular impingement(FAI)is a predisposing factor for secondary osteoarthritis of the hip joint.The two extensively described impingement mechanisms of FAI are CAM and Pincer-type.Initially managed conservatively,operative intervention should be offered to the persistently symptomatic patient.The measurement of the alpha angle is considered a standard method of assessing the severity of pathology in Cam-type FAI on pre-operative plain radiographs.The radiological correction of the alpha angle has not been previously compared between different surgical approaches.We hypothesize that there is no difference in alpha angle correction between Ganz surgical hip dislocation and the anterior mini-open approach.AIM To compare the magnitude of alpha angle correction achieved by using the Ganz surgical hip dislocation and the anterior mini-open approach.METHODS This is a retrospective study assessing seventy-nine patients identified in a 5-year period.These patients had preoperative radiographic evidence of FAI and underwent surgery by a single surgeon at our institution,a tertiary care center.Patients with missing radiographic documentation,radiographs with insufficient quality which then precluded accurate measurement of the angleα,a diagnosed congenital condition,isolated type II pathology(Pincer),and history of prior surgery were excluded from the study.Either the Ganz surgical hip dislocation or the anterior mini open approach was used.Postoperative radiographic evaluation of the alpha angle between the two surgical methods was done and corrected for age and gender using two-sample t-tests and Chi-square analyses.RESULTS A total of 79 patients met the inclusion and exclusion criteria.Forty-seven males(mean age of 35.3,range 16-53)and 32 females(mean age 36.7,range 16-60)were enrolled.Forty-seven patients underwent the anterior mini-open approach,and 32 underwent the Ganz surgical hip dislocation.There were no significant differences in age between the two surgical groups or in pre-and post-operative alpha angles based on patient gender.The mean pre-operative alpha angle for the Ganz surgical hip dislocation group was 88.0 degrees(SD 12.3)and 99.4 degrees(SD 7.2)for the anterior mini-open group.Mean post-operative angles were 49.9 degrees(SD 4.3)for the Ganz surgical hip dislocation and 43.8(SD 4.3)degrees for the anterior mini-open group.There was a statistically significant difference in patient’s pre-operative and post-operative angles(P=0.000)with both surgical approaches.CONCLUSION Statistically significant decreases in alpha angle were noted for both surgical techniques,with larger decreases seen in the anterior mini-open group.
基金Supported by National Natural Science Foundation of China(No.81902751).
文摘AIM:To explore the effect of Alpha angle and Kappa angle before multifocal intraocular lenses(MIOLs)implantation on postoperative visual quality of patients.METHODS:Before and 3mo after cataract surgery,Alpha angle and Kappa angle were collected using IOL Master 700,iTrace,and Pentacam for clinical observation.Postoperative visual quality indicators,including high-order aberrations(HOA),modulation transfer function(MTF)and point spread function(PSF),were collected using iTrace.multiple linear regression analysis was used to analyze the correlation of the Kappa angle and the Alpha angle with age,axial length(AL),anterior chamber depth(ACD),keratometry(K),lens thickness(LT)and corneal white to white distance(WTW).Pearson correlation coefficient was used to analyze the correlation between Alpha angle and Kappa angle;Bland Altman analysis was used to evaluate the consistency of pairwise detection results of three instruments.RESULTS:The Alpha angle was modeled as Alpha=2.230+0.003×age-0.036×AL-0.025×K-0.058×WTW and the Kappa angle was modeled as Kappa=0.685+0.003×age-0.013×K-0.061×WTW.The correlation between the total Alpha angle and Kappa angle of the three instruments was weakly positive(r=0.291,P=0.000).Comparing the measurement of Alpha angle and Kappa angle using three instruments,only IOL Master 700 and iTrace showed good consistency in measuring Kappa angle(P=0.4254).After 3mo of surgery,the Alpha angle and Kappa angle significantly decreased(P=0.011,0.018;P=0.008,0.036).△Kappa=1.136-0.021×AL-0.013×K.Kappa angle could positively predict HOA(β=0.18,P=0.000),MTF(β=0.171,P=0.000),PSF(β=0.088,P=0.000),Alpha angle cannot(P>0.05).CONCLUSION:The patients with older age,flatter K and shorter WTW should be alert to the possibility of larger Alpha angle and Kappa angle.Alpha angle should also consider the factor of AL.When selecting patients with MIOLs implantation,there is no need to consider the Alpha angle.Careful consideration should be given to the Kappa angle,and the preoperative standard of<0.5 mm can refer to△Kappa=1.136-0.021×AL-0.013×K and be appropriately relaxed.
文摘AIM:To investigate how angles kappa and alpha affect postoperative visual quality in patients with multifocal intraocular lens(mIOLs)implantation.METHODS:Retrospective cases series.A total of 46 patients(46 eyes)who underwent phacoemulsification were subsumed.The correlation between Preoperative angles kappa and alpha,wave-front aberrations and objective visual quality of cornea,internal,and total eye after surgery were analyzed using iTrace.RESULTS:The magnitude of angle kappa was negatively correlated with internal and total modulation transfer function(MTF)at 3 mm;the magnitude of angle kappa was positively correlated with astigmatism,trefoil,higher-order aberrations(HOAs)of both internal and total eye at 3 mm.The magnitude of angle alpha was negatively correlated with total MTF and total Strehl ratio at 3 mm.The magnitude of angle alpha was positively correlated with corneal coma at 5 mm,internal astigmatism at both 3 mm and 5 mm,and total spherical aberration(SA)at 3 mm.Multivariate linear regression analysis showed that,among candidate independent variables(kappa,alpha,astigmatism,SA,coma,trefoil,and HOAs),astigmatism is the only independent factor for altering corneal MTF at 3 mm and 5 mm;astigmatism and HOAs emerged as independent factors for altering internal MTF at 3 mm and 5 mm,and total MTF at 3 mm;astigmatism,SA and HOAs emerged as independent factors for altering total MTF at 5 mm.CONCLUSION:With greater preoperative angle kappa or angle alpha,patients who accept mIOL implantation tend to have larger internal astigmatism and HOAs,which resulting in poor visual quality,especially those with small pupil size.
文摘Prediction of roadheader performance plays a significant role in the plan of tunnel construction, which is influenced by different key parameters, including rock strength, discontinuity in rock mass, type and specifications of roadheader machine, and brittleness. The main aim of this study is to build a robust empirical equation based on rock mass properties for the roadheader performance prediction. For achieving the aim, a dataset composed of roadheader performance rate and rock properties is established using the dataset compiled from an underground coal mine located in a remote rugged desert environment some 85 km south of Tabas City in mid east Iran. By using gathered data, the statistical analyses are conducted between rock mass properties and roadheader performance to find whether there is a significant relationship between input variables and roadheader performance. The results show that rock mass properties have a considerable impact on the rate of the roadheader performance. It is demonstrated that the proposed model can accurately predict the roadheader performance as a function of rock mass properties.
