Ruptured intracranial aneurysms(RIAs)are a leading cause of subarachnoid haemorrhage(SAH)and are associated with a poor prognosis and high mortality rate.Computed tomography angiography(CTA)is the preferred imaging mo...Ruptured intracranial aneurysms(RIAs)are a leading cause of subarachnoid haemorrhage(SAH)and are associated with a poor prognosis and high mortality rate.Computed tomography angiography(CTA)is the preferred imaging moda-lity for the diagnosis of RIAs,as it is considered to be a fast,economical,and less invasive method.In this letter,regarding an original study presented by Elmo-kadem et al,we present our insights and discuss how CTA can better assist in clinical decision-making for patients with RIAs complicated by SAH.展开更多
Background:To compare the safety and efficacy of LVIS stent-assisted coiling with those of laser-cut stent-assisted coiling for the treatment of acutely ruptured wide-necked intracranial aneurysms.Methods:Patients wit...Background:To compare the safety and efficacy of LVIS stent-assisted coiling with those of laser-cut stent-assisted coiling for the treatment of acutely ruptured wide-necked intracranial aneurysms.Methods:Patients with acutely ruptured wide-necked intracranial aneurysms treated with LVIS stent-assisted coiling(LVIS stent group)and laser-cut stent-assisted coiling(laser-cut stent group)were retrospectively reviewed from January 2014 to December 2017.Propensity score matching was used to adjust for potential differences in age,sex,aneurysm location,aneurysm size,neck width,Hunt-Hess grade,and modified Fisher grade.Perioperative procedure-related complications and clinical and angiographic follow-up outcomes were compared.Univariate and multivariate analyses were performed to determine the associations between procedure-related complications and potential risk factors.Results:A total of 142 patients who underwent LVIS stent-assisted coiling and 93 patients who underwent laser-cut stent-assisted coiling were enrolled after 1:2 propensity score matching.The angiographic follow-up outcomes showed that the LVIS stent group had a slightly higher complete occlusion rate and lower recurrence rate than the laser-cut stent group(92.7%vs 80.6%;3.7%vs 9.7%,P=0.078).The clinical outcomes at discharge and follow-up between the two groups demonstrated no significant differences(P=0.495 and P=0.875,respectively).The rates of intraprocedural thrombosis,postprocedural thrombosis,postoperative early rebleeding,and procedure-related death were 0.7%(1/142),1.4%(2/142),2.8%(4/142),and 2.1%(3/142)in the LVIS stent group,respectively,and 4.3%(4/93),2.2%(2/93),1.1%(1/93),and 3.2%(3/93)in the laser-cut stent group,respectively(P=0.082,0.649,0.651,and 0.683).Nevertheless,the rates of overall procedure-related complications and intraprocedural rupture in the LVIS stent group were significantly lower than those in the laser-cut stent group(5.6%vs 14.0%,P=0.028;0.7%vs 6.5%,P=0.016).Multivariate analysis showed that laser-cut stent-assisted coiling was an independent predictor for overall procedurerelated complications(OR=2.727,P=0.037);a history of diabetes(OR=7.275,P=0.027)and other cerebrovascular diseases(OR=8.083,P=0.022)were independent predictors for ischemic complications,whereas none of the factors were predictors for hemorrhagic complications.Conclusions:Compared with laser-cut stent-assisted coiling,LVIS stent-assisted coiling for the treatment of acutely ruptured wide-necked intracranial aneurysms could reduce the rates of overall procedure-related complications and intraprocedural rupture.展开更多
Background: It has been conclusively established that intracranial aneurysms measuring a diameter below 7 mm pose a minimal risk of rupture. Conversely, those exhibiting irregular morphology or featuring the presence ...Background: It has been conclusively established that intracranial aneurysms measuring a diameter below 7 mm pose a minimal risk of rupture. Conversely, those exhibiting irregular morphology or featuring the presence of a sac necessitate a more stringent and rigorous management approach. Objective: The primary aim of this study is to delve into the morphological features of ruptured aneurysms situated in distinct regions of the brain. Furthermore, we endeavor to assess the degree of safety and efficacy associated with stent-assisted embolization as a treatment modality for these ruptured aneurysms. Methods: This retrospective study encompassed a cohort of 467 patients who presented with intracranial ruptured aneurysms and were diagnosed through a combination of computed tomography (CT) and digital subtraction angiography (DSA) at Nanfang Hospital of Southern Medical University, spanning from January 2009 to December 2019. The following clinical parameters were meticulously recorded: aneurysm height, width, neck measurements, immediate Raymond grade assessments, and any perioperative complications experienced. Results: Within the study population, the average dimensions of ruptured aneurysms were found to be 4.26 ± 2.10 mm (width), 4.86 ± 2.38 mm (height), and 4.04 ± 1.87 mm (neck). Categorically, the most prevalent types of aneurysms were 170 cases of anterior communicating artery aneurysms (accounting for 36.4%), followed by 161 cases of posterior communicating artery aneurysms (34.5%), 56 cases of middle cerebral artery aneurysms (12.0%), 13 cases of anterior cerebral artery aneurysms (2.8%), 45 cases of paraclinoid aneurysms (9.6%), 6 cases of superior pituitary artery aneurysms (1.3%), 7 cases of anterior choroidal artery aneurysms (1.5%), and 9 cases of vertebrobasilar artery aneurysms (2.0%). Notably, 18 patients (3.9%) presented with ruptured aneurysms coexisting with ascus. Regarding treatment approaches, 228 cases (48.8%) underwent stent-assisted embolization, 234 cases (50.1%) received coils embolization, and 5 cases (1.1%) were treated with the dual-catheter technique. Immediately post-treatment, 422 patients (90.4%) attained a Raymond Class I status, with a procedure-related complication rate of 0.9%. Importantly, no statistically significant differences were observed in the incidence of perioperative complications across the three distinct treatment groups (P = 0.505). Conclusion: The outcomes of this study affirm the safety and efficacy of stent-assisted embolization as a treatment modality for ruptured aneurysms.展开更多
Background:The purpose of this analysis is to evaluate the current evidence with regard to the effectiveness and safety between coiling and clipping in patients with ruptured intracranial aneurysms(RIAs).Methods:We pe...Background:The purpose of this analysis is to evaluate the current evidence with regard to the effectiveness and safety between coiling and clipping in patients with ruptured intracranial aneurysms(RIAs).Methods:We performed a meta-analysis that compared clipping with coiling between July 2000 and September 2021.PubMed,EMBASE,and the Cochrane Library were searched for related articles systematically.And the treatment efficacy and postoperative complications were analyzed.Results:We identified three randomized controlled trials and thirty-seven observational studies involving 60,875 patients with ruptured cerebral aneurysms.The summary results showed that coiling was related a better quality of life(mRS0-2;OR=1.327;CI=1.093-1.612;p<0.05),a higher risk of mortality(OR=1.116;CI=1.054-1.180;p<0.05),higher rate of rebleeding(RR=1.410;CI=1.092-1.822;p<0.05),lower incidence of vasospasm(OR=0.787;CI=0.649-0.954;p<0.05),higher risk of hydrocephalous(RR=1.143;CI=1.043-1.252;p<0.05),lower risk of cerebral infarction(RR=0.669;CI=0.596-0.751;p<0.05),lower risk of neuro deficits(RR=0.720;CI=0.582-0.892;p<0.05),and a lower rate of complete occlusion(OR=0.495;CI=0.280-0.876;p<0.05).Conclusion:Coiling was significantly associated with a better life quality(mRS0-2),a lower incidence of postoperative complications,and a higher rate of mortality,rebleeding,hydrocephalous,and a lower rate of complete occlusion than clipping.展开更多
Background:Rebleeding can cause a catastrophic outcome after aneurysmal subarachnoid hemorrhage.A clinical+morphology nomogram was promoted in our previous study to assist in discriminating the rupture intracranial an...Background:Rebleeding can cause a catastrophic outcome after aneurysmal subarachnoid hemorrhage.A clinical+morphology nomogram was promoted in our previous study to assist in discriminating the rupture intracranial aneurysms(RIAs)with a high risk of rebleeding.The aim of this study was to validate the predictive accuracy of this nomogram model.Method:The patients with RIAs in two medical centers from December 2020 to September 2021 were retrospectively reviewed,whose clinical and morphological parameters were collected.The Cox regression model was employed to identify the risk factors related to rebleeding after their admission.The predicting accuracy of clinical+morphological nomogram,ELAPSS score and PHASES score was compared based on the area under the curves(AUCs).Results:One hundred thirty-eight patients with RIAs were finally included in this study,20 of whom suffering from rebleeding after admission.Hypertension(hazard ratio(HR),2.54;a confidence interval of 95%(CI),1.01-6.40;P=0.047),bifurcation(HR,3.88;95%CI,1.29-11.66;P=0.016),and AR(HR,2.68;95%CI,1.63-4.41;P<0.001)were demonstrated through Cox regression analysis as the independent risk factors for rebleeding after admission.The clinical+morphological nomogram had the highest predicting accuracy(AUC,0.939,P<0.01),followed by the bifurcation(AUC,0.735,P=0.001),AR(AUC,0.666,P=0.018),and ELAPSS score(AUC,0.682,P=0.009).Hypertension(AUC,0.693,P=0.080)or PHASES score(AUC,0.577,P=0.244)could not be used to predict the risk of rebleeding after admission.The calibration curve for the probability of rebleeding showed a good agreement between the prediction through clinical+morphological nomogram and actual observation.Conclusion:Hypertension,bifurcation site,and AR were independent risk factors related to the rebleeding of RIAs after admission.The clinical+morphological nomogram could help doctors to identify the high-risk RIAs with a high predictive accuracy.展开更多
Intracranial aneurysms have a high prevalence in the population and are associated with high rates of disability and mortality after rupture.It is essential to assess the rupture risk of unruptured intracranial aneury...Intracranial aneurysms have a high prevalence in the population and are associated with high rates of disability and mortality after rupture.It is essential to assess the rupture risk of unruptured intracranial aneurysms by selecting appropriate morphological parameters.However,there is still a need for consistent evidence-based medicine to provide a clinical reference.Therefore,the expert group has jointly written this consensus based on literature review and clinical experience,aiming to provide a standardized reference for predicting the development of intracranial aneurysms and evaluating their rupture risk factors.展开更多
Background:Tiny false intracranial rupture aneurysms are particularly rare. It is challenged both to neurosurgery and endovascular treatment.Methods:We present here five rare cases of perforator tiny aneurysms that we...Background:Tiny false intracranial rupture aneurysms are particularly rare. It is challenged both to neurosurgery and endovascular treatment.Methods:We present here five rare cases of perforator tiny aneurysms that were diagnosed based on DSA. These patients were found due to SAH, and they decided to treat these aneurysms with endovascular therapy. After numerous attempts, the coiling microcatheter failed to access the aneurysms. As a result, the aneurysms finally were treated with guidewire manipulation.Results:Mean follow-up time was about 10.4 months. The outcomes of the 5 cases were all surprisingly excel ent. The patients were followed up with angiography and telephone till now. No revascularization of aneurysm was found.Conclusions:This paper demonstrated for the first time to our knowledge that tiny false intracranial aneurysm may be treated with guidewire manipulation. While larger studies with long-term follow-up are required to validate these promising results, guidewire manipulation is a new approach worth considering when microcatheter cannot enter aneurysm.展开更多
The rupture of intracranial aneurysm would lead to serious consequences, and different shapes of aneurysm have different effects on the rupture. In this paper, a mechanical analysis method is proposed for calculating ...The rupture of intracranial aneurysm would lead to serious consequences, and different shapes of aneurysm have different effects on the rupture. In this paper, a mechanical analysis method is proposed for calculating the rupture trend of intracranial aneurysm based on three-dimensional image reconstruction and hemodynamic numerical calculation and evaluation. Firstly, the modeling of actual intracranial aneurysms was conducted based on CT intracranial aneurysm angiography plane images. Secondly, the model was simplified from the perspective of fluid mechanics analysis to establish the mechanical model of different forms of intracranial aneurysms. Then the flow mechanics characteristics of each model in rigid boundary and fluid-structure coupling boundary were analyzed. The simulation research was conducted on the condition of normal pressure difference and pressure pulsation, and the most dangerous position of intracranial aneurysms rupture was analyzed. The results validate the correctness of theoretical analysis.展开更多
Clipping and coiling are currently the two alternatives in treatment of ruptured cerebral aneurysms. In spite of some meritorious analysis, further discussion is helpful to understand the actual state of art. Retreatm...Clipping and coiling are currently the two alternatives in treatment of ruptured cerebral aneurysms. In spite of some meritorious analysis, further discussion is helpful to understand the actual state of art. Retreatment and rebleeding rates clearly favors clipping, although short-term functional outcome seems to be beneficial for clipping, while this different is not such if we perform the comparison at a longer follow up. Longterm follow ups and cost analysis are mandatory to have a clear view of the current picture in treatment of subarachnoid hemorrhage. Treatment strategy should be made by a multi-disciplinary team in accredited centers with proficient experience in both techniques.展开更多
基金Supported by Natural Science Foundation Project of Chongqing,No.CSTB2024NSCQ-MSX1265.
文摘Ruptured intracranial aneurysms(RIAs)are a leading cause of subarachnoid haemorrhage(SAH)and are associated with a poor prognosis and high mortality rate.Computed tomography angiography(CTA)is the preferred imaging moda-lity for the diagnosis of RIAs,as it is considered to be a fast,economical,and less invasive method.In this letter,regarding an original study presented by Elmo-kadem et al,we present our insights and discuss how CTA can better assist in clinical decision-making for patients with RIAs complicated by SAH.
基金This work was supported by the National Key Research and Development Program of China(grant no.: 2016YFC1300703)National Natural Science Foundation of China(grant no.: 81701136, 81571126).
文摘Background:To compare the safety and efficacy of LVIS stent-assisted coiling with those of laser-cut stent-assisted coiling for the treatment of acutely ruptured wide-necked intracranial aneurysms.Methods:Patients with acutely ruptured wide-necked intracranial aneurysms treated with LVIS stent-assisted coiling(LVIS stent group)and laser-cut stent-assisted coiling(laser-cut stent group)were retrospectively reviewed from January 2014 to December 2017.Propensity score matching was used to adjust for potential differences in age,sex,aneurysm location,aneurysm size,neck width,Hunt-Hess grade,and modified Fisher grade.Perioperative procedure-related complications and clinical and angiographic follow-up outcomes were compared.Univariate and multivariate analyses were performed to determine the associations between procedure-related complications and potential risk factors.Results:A total of 142 patients who underwent LVIS stent-assisted coiling and 93 patients who underwent laser-cut stent-assisted coiling were enrolled after 1:2 propensity score matching.The angiographic follow-up outcomes showed that the LVIS stent group had a slightly higher complete occlusion rate and lower recurrence rate than the laser-cut stent group(92.7%vs 80.6%;3.7%vs 9.7%,P=0.078).The clinical outcomes at discharge and follow-up between the two groups demonstrated no significant differences(P=0.495 and P=0.875,respectively).The rates of intraprocedural thrombosis,postprocedural thrombosis,postoperative early rebleeding,and procedure-related death were 0.7%(1/142),1.4%(2/142),2.8%(4/142),and 2.1%(3/142)in the LVIS stent group,respectively,and 4.3%(4/93),2.2%(2/93),1.1%(1/93),and 3.2%(3/93)in the laser-cut stent group,respectively(P=0.082,0.649,0.651,and 0.683).Nevertheless,the rates of overall procedure-related complications and intraprocedural rupture in the LVIS stent group were significantly lower than those in the laser-cut stent group(5.6%vs 14.0%,P=0.028;0.7%vs 6.5%,P=0.016).Multivariate analysis showed that laser-cut stent-assisted coiling was an independent predictor for overall procedurerelated complications(OR=2.727,P=0.037);a history of diabetes(OR=7.275,P=0.027)and other cerebrovascular diseases(OR=8.083,P=0.022)were independent predictors for ischemic complications,whereas none of the factors were predictors for hemorrhagic complications.Conclusions:Compared with laser-cut stent-assisted coiling,LVIS stent-assisted coiling for the treatment of acutely ruptured wide-necked intracranial aneurysms could reduce the rates of overall procedure-related complications and intraprocedural rupture.
文摘Background: It has been conclusively established that intracranial aneurysms measuring a diameter below 7 mm pose a minimal risk of rupture. Conversely, those exhibiting irregular morphology or featuring the presence of a sac necessitate a more stringent and rigorous management approach. Objective: The primary aim of this study is to delve into the morphological features of ruptured aneurysms situated in distinct regions of the brain. Furthermore, we endeavor to assess the degree of safety and efficacy associated with stent-assisted embolization as a treatment modality for these ruptured aneurysms. Methods: This retrospective study encompassed a cohort of 467 patients who presented with intracranial ruptured aneurysms and were diagnosed through a combination of computed tomography (CT) and digital subtraction angiography (DSA) at Nanfang Hospital of Southern Medical University, spanning from January 2009 to December 2019. The following clinical parameters were meticulously recorded: aneurysm height, width, neck measurements, immediate Raymond grade assessments, and any perioperative complications experienced. Results: Within the study population, the average dimensions of ruptured aneurysms were found to be 4.26 ± 2.10 mm (width), 4.86 ± 2.38 mm (height), and 4.04 ± 1.87 mm (neck). Categorically, the most prevalent types of aneurysms were 170 cases of anterior communicating artery aneurysms (accounting for 36.4%), followed by 161 cases of posterior communicating artery aneurysms (34.5%), 56 cases of middle cerebral artery aneurysms (12.0%), 13 cases of anterior cerebral artery aneurysms (2.8%), 45 cases of paraclinoid aneurysms (9.6%), 6 cases of superior pituitary artery aneurysms (1.3%), 7 cases of anterior choroidal artery aneurysms (1.5%), and 9 cases of vertebrobasilar artery aneurysms (2.0%). Notably, 18 patients (3.9%) presented with ruptured aneurysms coexisting with ascus. Regarding treatment approaches, 228 cases (48.8%) underwent stent-assisted embolization, 234 cases (50.1%) received coils embolization, and 5 cases (1.1%) were treated with the dual-catheter technique. Immediately post-treatment, 422 patients (90.4%) attained a Raymond Class I status, with a procedure-related complication rate of 0.9%. Importantly, no statistically significant differences were observed in the incidence of perioperative complications across the three distinct treatment groups (P = 0.505). Conclusion: The outcomes of this study affirm the safety and efficacy of stent-assisted embolization as a treatment modality for ruptured aneurysms.
文摘Background:The purpose of this analysis is to evaluate the current evidence with regard to the effectiveness and safety between coiling and clipping in patients with ruptured intracranial aneurysms(RIAs).Methods:We performed a meta-analysis that compared clipping with coiling between July 2000 and September 2021.PubMed,EMBASE,and the Cochrane Library were searched for related articles systematically.And the treatment efficacy and postoperative complications were analyzed.Results:We identified three randomized controlled trials and thirty-seven observational studies involving 60,875 patients with ruptured cerebral aneurysms.The summary results showed that coiling was related a better quality of life(mRS0-2;OR=1.327;CI=1.093-1.612;p<0.05),a higher risk of mortality(OR=1.116;CI=1.054-1.180;p<0.05),higher rate of rebleeding(RR=1.410;CI=1.092-1.822;p<0.05),lower incidence of vasospasm(OR=0.787;CI=0.649-0.954;p<0.05),higher risk of hydrocephalous(RR=1.143;CI=1.043-1.252;p<0.05),lower risk of cerebral infarction(RR=0.669;CI=0.596-0.751;p<0.05),lower risk of neuro deficits(RR=0.720;CI=0.582-0.892;p<0.05),and a lower rate of complete occlusion(OR=0.495;CI=0.280-0.876;p<0.05).Conclusion:Coiling was significantly associated with a better life quality(mRS0-2),a lower incidence of postoperative complications,and a higher rate of mortality,rebleeding,hydrocephalous,and a lower rate of complete occlusion than clipping.
基金the projects of National Natural Science Foundation of China(Grant Nos.82071296,81471210,and 81671129)"Major special projects in the 13th five-year plan"(Grant No.2016YFC1301800)+1 种基金"Major special projects in the 14th five-year plan"(Grant No.2021YFC2501100)The sponsors had no role in the design or conduct of this research.
文摘Background:Rebleeding can cause a catastrophic outcome after aneurysmal subarachnoid hemorrhage.A clinical+morphology nomogram was promoted in our previous study to assist in discriminating the rupture intracranial aneurysms(RIAs)with a high risk of rebleeding.The aim of this study was to validate the predictive accuracy of this nomogram model.Method:The patients with RIAs in two medical centers from December 2020 to September 2021 were retrospectively reviewed,whose clinical and morphological parameters were collected.The Cox regression model was employed to identify the risk factors related to rebleeding after their admission.The predicting accuracy of clinical+morphological nomogram,ELAPSS score and PHASES score was compared based on the area under the curves(AUCs).Results:One hundred thirty-eight patients with RIAs were finally included in this study,20 of whom suffering from rebleeding after admission.Hypertension(hazard ratio(HR),2.54;a confidence interval of 95%(CI),1.01-6.40;P=0.047),bifurcation(HR,3.88;95%CI,1.29-11.66;P=0.016),and AR(HR,2.68;95%CI,1.63-4.41;P<0.001)were demonstrated through Cox regression analysis as the independent risk factors for rebleeding after admission.The clinical+morphological nomogram had the highest predicting accuracy(AUC,0.939,P<0.01),followed by the bifurcation(AUC,0.735,P=0.001),AR(AUC,0.666,P=0.018),and ELAPSS score(AUC,0.682,P=0.009).Hypertension(AUC,0.693,P=0.080)or PHASES score(AUC,0.577,P=0.244)could not be used to predict the risk of rebleeding after admission.The calibration curve for the probability of rebleeding showed a good agreement between the prediction through clinical+morphological nomogram and actual observation.Conclusion:Hypertension,bifurcation site,and AR were independent risk factors related to the rebleeding of RIAs after admission.The clinical+morphological nomogram could help doctors to identify the high-risk RIAs with a high predictive accuracy.
基金supported by the Project of“Key Research&Development(R&D)Plan of Zhejiang Province”[NO.2019C03034].
文摘Intracranial aneurysms have a high prevalence in the population and are associated with high rates of disability and mortality after rupture.It is essential to assess the rupture risk of unruptured intracranial aneurysms by selecting appropriate morphological parameters.However,there is still a need for consistent evidence-based medicine to provide a clinical reference.Therefore,the expert group has jointly written this consensus based on literature review and clinical experience,aiming to provide a standardized reference for predicting the development of intracranial aneurysms and evaluating their rupture risk factors.
基金the National Natural Science Foundation of China (grant number 81171078, 81,541,029 and 81,271,166)
文摘Background:Tiny false intracranial rupture aneurysms are particularly rare. It is challenged both to neurosurgery and endovascular treatment.Methods:We present here five rare cases of perforator tiny aneurysms that were diagnosed based on DSA. These patients were found due to SAH, and they decided to treat these aneurysms with endovascular therapy. After numerous attempts, the coiling microcatheter failed to access the aneurysms. As a result, the aneurysms finally were treated with guidewire manipulation.Results:Mean follow-up time was about 10.4 months. The outcomes of the 5 cases were all surprisingly excel ent. The patients were followed up with angiography and telephone till now. No revascularization of aneurysm was found.Conclusions:This paper demonstrated for the first time to our knowledge that tiny false intracranial aneurysm may be treated with guidewire manipulation. While larger studies with long-term follow-up are required to validate these promising results, guidewire manipulation is a new approach worth considering when microcatheter cannot enter aneurysm.
文摘The rupture of intracranial aneurysm would lead to serious consequences, and different shapes of aneurysm have different effects on the rupture. In this paper, a mechanical analysis method is proposed for calculating the rupture trend of intracranial aneurysm based on three-dimensional image reconstruction and hemodynamic numerical calculation and evaluation. Firstly, the modeling of actual intracranial aneurysms was conducted based on CT intracranial aneurysm angiography plane images. Secondly, the model was simplified from the perspective of fluid mechanics analysis to establish the mechanical model of different forms of intracranial aneurysms. Then the flow mechanics characteristics of each model in rigid boundary and fluid-structure coupling boundary were analyzed. The simulation research was conducted on the condition of normal pressure difference and pressure pulsation, and the most dangerous position of intracranial aneurysms rupture was analyzed. The results validate the correctness of theoretical analysis.
文摘Clipping and coiling are currently the two alternatives in treatment of ruptured cerebral aneurysms. In spite of some meritorious analysis, further discussion is helpful to understand the actual state of art. Retreatment and rebleeding rates clearly favors clipping, although short-term functional outcome seems to be beneficial for clipping, while this different is not such if we perform the comparison at a longer follow up. Longterm follow ups and cost analysis are mandatory to have a clear view of the current picture in treatment of subarachnoid hemorrhage. Treatment strategy should be made by a multi-disciplinary team in accredited centers with proficient experience in both techniques.
