endovascular coiling of cerebral aneurysms has become widely accepted as a safe and effective alternative to surgical clipping of cerebral aneurysms.14 advancements in technology , such as trackable balloons , self expanding stents , and flow diverters , allow endovascular treatment of most cerebral aneurysms.511 however , aneurysm residuals or recanalization remains a challenge . to this end , continued effort must be made to advance coil technology in order to improve long term occlusion rates . the medina coil was designed as a next generation coil technology that incorporates the versatility , technical performance , and safety profile of coils with excellent filling capabilities and , hopefully , more robust long term occlusion rates . this report details the initial clinical experience with this next generation three - dimensional coil in order to assess the immediate periprocedural safety in the treatment of cerebral aneurysms . the medina coil has been granted ce mark clearance from the european union notified body , and is designed to treat all saccular aneurysms of any morphology or location . the medina coil is a three - dimensional coil made from a radiopaque , shape set core wire , and shape memory alloy outer filaments that are shaped into petals . when deployed , the medina coil begins in a linear configuration and then deforms to fill space within the aneurysm . in its unconstrained state , the device retains a linear form with the petals unfolding into a wave form pattern , as shown in figure 1 . but , as the device is introduced into an aneurysm , it bends on itself and deforms to both cover the aneurysm ostium as well as to create a stable structure , while still allowing contrast flow for visualization . similar to conventional coils , it can be retracted and repositioned or removed completely , as desired . loops rather than thinner wires , as with conventional coils , which allows for stable anchoring of the coil within the aneurysm sac . the filler coils are softer , and are designed to fill the internal space within the framing coils . patients were selected based on aneurysm size of at least 5  mm in diameter , as the smallest currently available device is 5  mm in diameter . briefly , a 6 f groin sheath was used in the groin to allow a 6 f guide catheter to be placed into the distal cervical vertebral or carotid artery . patients were heparinized with 5000 units , and no one received antiplatelet agents prior to surgery . a 0.021  inch prowler ( codman , nadick , massachusetts , usa ) or 0.021  inch rebar ( micro therapeutics , irvine , california , usa ) microcatheter a medina framing coil was chosen using sizing selection in the same manner as choosing traditional coils . if the deployed coil configuration was felt to be unacceptable at any point during the deployment , the coil could always be retracted and redeployed , consistent with current conventional coils . subsequent coils were then sequentially placed until placement of further coils was not possible or felt to be unnecessary . procedure time was defined as the length of time that the microcatheter was present in the aneurysm . clinical outcomes were documented at discharge by the patients primary treating physician ( om ) . the medina coil has been granted ce mark clearance from the european union notified body , and is designed to treat all saccular aneurysms of any morphology or location . the medina coil is a three - dimensional coil made from a radiopaque , shape set core wire , and shape memory alloy outer filaments that are shaped into petals . when deployed , the medina coil begins in a linear configuration and then deforms to fill space within the aneurysm . in its unconstrained state , the device retains a linear form with the petals unfolding into a wave form pattern , as shown in figure 1 . but , as the device is introduced into an aneurysm , it bends on itself and deforms to both cover the aneurysm ostium as well as to create a stable structure , while still allowing contrast flow for visualization . similar to conventional coils , it can be retracted and repositioned or removed completely , as desired . loops rather than thinner wires , as with conventional coils , which allows for stable anchoring of the coil within the aneurysm sac . the filler coils are softer , and are designed to fill the internal space within the framing coils . patients were selected based on aneurysm size of at least 5  mm in diameter , as the smallest currently available device is 5  mm in diameter . briefly , a 6 f groin sheath was used in the groin to allow a 6 f guide catheter to be placed into the distal cervical vertebral or carotid artery . patients were heparinized with 5000 units , and no one received antiplatelet agents prior to surgery . a 0.021  inch prowler ( codman , nadick , massachusetts , usa ) or 0.021  inch rebar ( micro therapeutics , irvine , california , usa ) microcatheter a medina framing coil was chosen using sizing selection in the same manner as choosing traditional coils . if the deployed coil configuration was felt to be unacceptable at any point during the deployment , the coil could always be retracted and redeployed , consistent with current conventional coils . subsequent coils were then sequentially placed until placement of further coils was not possible or felt to be unnecessary . procedure time was defined as the length of time that the microcatheter was present in the aneurysm . clinical outcomes were documented at discharge by the patients primary treating physician ( om ) . aneurysm locations were middle cerebral ( n=3 ) , anterior communicating ( n=2 ) , basilar apex , carotid terminus , ophthalmic , posterior communicating , and pericallosal arteries ( table 1 ) . all aneurysms were treated electively , although one patient had suffered a subarachnoid hemorrhage 1  month prior to treatment and one other patient had bled a year prior to treatment . summary of nine initially treated aneurysms , with location , size , number of coils used , procedure time , and angiographic outcome procedure time was defined as placement of first coil introduced into the microcatheter to last coil detached . acom , anterior communicating artery ; mca , middle cerebral artery ; pcom , posterior communicating artery . all aneurysms were treated with medina coils alone , except for one case in which a remaining filling segment at the aneurysm base was too small to accommodate a 5  mm filling coil , and therefore a traditional coil was used . no periprocedural or postprocedure related clinical complications , such as stroke or aneurysm bleeding , were encountered . acute residual contrast filling within the coil loops was present in all cases except one , where the final device implanted was a conventional coil . one aneurysm treated was a 6  mm wide necked middle cerebral artery bifurcation aneurysm residual 1  month after surgical clipping . procedure time was recorded from the first coil introduced into the microcatheter to the last coil detached . a patient with multiple intracranial aneurysms presented for elective endovascular treatment of his aneurysms . the aneurysm at the carotid terminus measured 5.2  mm4.9  mm with a broad neck ( figure 2 ) . the aneurysm was treated with a single 6  mm medina framing coil through a prowler plus microcatheter with a 9  min procedure time . control angiography demonstrated significant contrast flow within the coil loops , but apparent stagnation in flow . follow - up angiogram at 1  month was performed during workup to address the patient s remaining cerebral aneurysms . follow - up angiogram demonstrated > 95% occlusion of the aneurysm with a small neck residual , which was present immediately postprocedure and remained stable in size . ( a ) working frontal digital subtraction angiography ( dsa ) of a 5  mm left carotid terminus aneurysm . ( b , left ) native magnified working view of the coil mass filling the aneurysm and ( right ) the same projection dsa of the aneurysm occluded with a very small neck residual . ( c ) one month follow - up dsa magnified working view with stable aneurysm occlusion and a very small neck remnant . this patient experienced a  subarachnoid hemorrhage 1  month previously from a 17  mm9  mm with 5.5  mm neck left anterior communicating region aneurysm ( figures 3 and 4 ) . an 8  mm medina framing coil was used to secure the dome of the aneurysm . a second 7  mm median framing coil was complexed with the first coil and used to create a proximal basket covering the aneurysm ostium . complexing framing coils to create a larger or longer coil mass is a common endovascular strategy for oblong and narrow aneurysms or when the aneurysm is much larger than the available coils . the remaining unfilled coil volume within the framing basket was subsequently filled with a 6  mm medina filling coil and then two 5  mm filling coils . the final angiogram showed coils filling the aneurysm with some contrast penetrating the proximal coil mass , and the patency of the parent anterior cerebral and anterior communicating arteries and their distal branches . ( a , b ) a patient who experienced a subarachnoid hemorrhage , 1  month previously , from a 17  mm9  mm with 5.5  mm neck left anterior communicating region aneurysm , as shown by three - dimensional digital subtraction angiography ( dsa ) and frontal working view . ( c ) final subtracted frontal ( left ) and native lateral ( right ) dsa control angiogram showing coils filling the aneurysm , with some contrast penetrating the proximal coil mass and patency of the parent anterior cerebral artery and anterior communicating arteries and their distal branches . ( a ) subtracted ( left ) and native ( right ) digital subtraction angiography ( dsa ) working view shows an 8  mm framing coil was used to secure the dome of the aneurysm . ( b ) subtracted ( left ) and native ( right ) dsa working view shows a second 7  mm framing coil was complexed with the first coil and used to create a proximal basket covering the aneurysm ostium . ( c ) subtracted ( left ) and native ( right ) dsa working view shows the remaining unfilled coil volume within the framing basket was subsequently filled with a 6  mm and then two 5  mm filling coils . the aneurysm at the carotid terminus measured 5.2  mm4.9  mm with a broad neck ( figure 2 ) . the aneurysm was treated with a single 6  mm medina framing coil through a prowler plus microcatheter with a 9  min procedure time . control angiography demonstrated significant contrast flow within the coil loops , but apparent stagnation in flow . follow - up angiogram at 1  month was performed during workup to address the patient s remaining cerebral aneurysms . follow - up angiogram demonstrated > 95% occlusion of the aneurysm with a small neck residual , which was present immediately postprocedure and remained stable in size . ( a ) working frontal digital subtraction angiography ( dsa ) of a 5  mm left carotid terminus aneurysm . ( b , left ) native magnified working view of the coil mass filling the aneurysm and ( right ) the same projection dsa of the aneurysm occluded with a very small neck residual . ( c ) one month follow - up dsa magnified working view with stable aneurysm occlusion and a very small neck remnant . this patient experienced a  subarachnoid hemorrhage 1  month previously from a 17  mm9  mm with 5.5  mm neck left anterior communicating region aneurysm ( figures 3 and 4 ) . an 8  mm medina framing coil was used to secure the dome of the aneurysm . a second 7 mm median framing coil was complexed with the first coil and used to create a proximal basket covering the aneurysm ostium . complexing framing coils to create a larger or longer coil mass is a common endovascular strategy for oblong and narrow aneurysms or when the aneurysm is much larger than the available coils . the remaining unfilled coil volume within the framing basket was subsequently filled with a 6  mm medina filling coil and then two 5  mm filling coils . the final angiogram showed coils filling the aneurysm with some contrast penetrating the proximal coil mass , and the patency of the parent anterior cerebral and anterior communicating arteries and their distal branches . ( a , b ) a patient who experienced a subarachnoid hemorrhage , 1  month previously , from a 17  mm9  mm with 5.5  mm neck left anterior communicating region aneurysm , as shown by three - dimensional digital subtraction angiography ( dsa ) and frontal working view . ( c ) final subtracted frontal ( left ) and native lateral ( right ) dsa control angiogram showing coils filling the aneurysm , with some contrast penetrating the proximal coil mass and patency of the parent anterior cerebral artery and anterior communicating arteries and their distal branches . ( a ) subtracted ( left ) and native ( right ) digital subtraction angiography ( dsa ) working view shows an 8  mm framing coil was used to secure the dome of the aneurysm . ( b ) subtracted ( left ) and native ( right ) dsa working view shows a second 7  mm framing coil was complexed with the first coil and used to create a proximal basket covering the aneurysm ostium . ( c ) subtracted ( left ) and native ( right ) dsa working view shows the remaining unfilled coil volume within the framing basket was subsequently filled with a 6  mm and then two 5  mm filling coils . the aneurysm at the carotid terminus measured 5.2  mm4.9  mm with a broad neck ( figure 2 ) . the aneurysm was treated with a single 6  mm medina framing coil through a prowler plus microcatheter with a 9  min procedure time . control angiography demonstrated significant contrast flow within the coil loops , but apparent stagnation in flow . follow - up angiogram at 1  month was performed during workup to address the patient s remaining cerebral aneurysms . follow - up angiogram demonstrated > 95% occlusion of the aneurysm with a small neck residual , which was present immediately postprocedure and remained stable in size . ( a ) working frontal digital subtraction angiography ( dsa ) of a 5  mm left carotid terminus aneurysm . ( b , left ) native magnified working view of the coil mass filling the aneurysm and ( right ) the same projection dsa of the aneurysm occluded with a very small neck residual . ( c ) one month follow - up dsa magnified working view with stable aneurysm occlusion and a very small neck remnant . this patient experienced a  subarachnoid hemorrhage 1  month previously from a 17  mm9  mm with 5.5  mm neck left anterior communicating region aneurysm ( figures 3 and 4 ) . an 8  mm medina framing coil was used to secure the dome of the aneurysm . a second 7  mm median framing coil was complexed with the first coil and used to create a proximal basket covering the aneurysm ostium . complexing framing coils to create a larger or longer coil mass is a common endovascular strategy for oblong and narrow aneurysms or when the aneurysm is much larger than the available coils . the remaining unfilled coil volume within the framing basket was subsequently filled with a 6  mm medina filling coil and then two 5  mm filling coils . the final angiogram showed coils filling the aneurysm with some contrast penetrating the proximal coil mass , and the patency of the parent anterior cerebral and anterior communicating arteries and their distal branches . ( a , b ) a patient who experienced a subarachnoid hemorrhage , 1  month previously , from a 17  mm9  mm with 5.5  mm neck left anterior communicating region aneurysm , as shown by three - dimensional digital subtraction angiography ( dsa ) and frontal working view . ( c ) final subtracted frontal ( left ) and native lateral ( right ) dsa control angiogram showing coils filling the aneurysm , with some contrast penetrating the proximal coil mass and patency of the parent anterior cerebral artery and anterior communicating arteries and their distal branches . ( a ) subtracted ( left ) and native ( right ) digital subtraction angiography ( dsa ) working view shows an 8  mm framing coil was used to secure the dome of the aneurysm . ( b ) subtracted ( left ) and native ( right ) dsa working view shows a second 7  mm framing coil was complexed with the first coil and used to create a proximal basket covering the aneurysm ostium . ( c ) subtracted ( left ) and native ( right ) dsa working view shows the remaining unfilled coil volume within the framing basket was subsequently filled with a 6  mm and then two 5  mm filling coils . wide necked medium and large sized aneurysms remain a common but challenging group of aneurysms in which to effect successful endovascular treatment . adjunctive devices such as balloons and stents are often required to achieve acceptable endovascular results , but these techniques have been reported to carry a higher risk.5 our early human experience with the medina coil , a next generation coil system , demonstrates the familiar coil ease of use methods and periprocedural safety . additionally , we experienced relatively short procedure times while utilizing few adjunctive technologies . the reported incidence of residual aneurysm necks after surgical clipping ranges from 3.8% to 18%.12 even after complete surgical clipping of an aneurysm , regrowth is thought to occur in up to 15% and rerupture in 2.7% of patients.13 
 14 a large endovascular series demonstrated recanalization rates as high as 42% in small aneurysms with wide necks.15 large and giant aneurysms demonstrated much higher recanalization rates of 87% and 90%.15 these limitations continue to drive innovation of new devices , such as flow diverters and bioactive coils.3 
 4 
 10 the medina coil is , very simply , an advanced coil technology that has some useful similarities with conventional coils , such as device size selection with framers and fillers . the final deployed device construct takes advantage of its surrounding filament design to provide improved volumetric filling of the aneurysm , and to hopefully result in better long term occlusion rates . at this early point of device use , the long term implications are unclear , but the early successful use of the technology in a safe manner consistent with current coil technology is extremely encouraging . to date , three of the medina treated aneurysms have reached a point at which follow - up angiography was possible . this limited angiographic follow - up provides an early indication that , like many traditional coils , this device progressively occludes aneurysms over time . these results are particularly exciting given the relative complexity of the aneurysms treated to date . in our experience , aneurysms treated with conventional coils tend to require about one coil per millimeter in length of the largest aneurysm dimension . additionally , we feel that the operative risk associated with placement of conventional coils increases as the number of coils placed increases . the medina coil was able to treat medium and large aneurysms with fewer coils than we thought would be expected if using conventional coils . an advantage of the medina coil design is that it places broader loops at the aneurysm neck that contain future coil loops , minimizing herniation or prolapse into the parent artery . anecdotally , this seems to improve the safety of placing subsequent coils into the aneurysm . the medina coil design was associated with very fast procedure times , with several aneurysms treated in < 10  min . there are limitations to this report , most significantly that it is a single center , operator adjudicated study . however , the early periprocedural safety of the medina coil appears to be well demonstrated . as more delayed angiographic data become available , and larger numbers of aneurysms receive treatment with the medina coil , it is possible that this technology will represent a major step forward in endovascular coil embolization of cerebral aneurysms . the medina coil system is a next generation coil that combines the familiar procedural safety and technique concepts associated with conventional coils with improved circumferential aneurysm filling , which it is thought will lead to improved long term outcomes . however , the data presented here demonstrate that , at a minimum , the medina coil system can be used safely to effect aneurysm embolization and that , in human cases , it functions in a manner consistent with current conventional coil technology .
introductionintracranial saccular aneurysms , if untreated , carry a high risk of morbidity and mortality from intracranial bleeding . 
 embolization coils are the most common treatment . 
 we describe the periprocedural safety and performance of the initial human experience with the next generation medina coil system.methodsthe medina coil system is a layered three - dimensional coil made from a radiopaque , shape set core wire , and shape memory alloy outer coil filaments . 
 nine aneurysms in five patients were selected for treatment with the medina coil system.resultsnine aneurysms in five patients , ranging from 5 to 17  mm in size in various locations , were treated with the medina coil system . 
 no procedural or periprocedural complications were encountered . 
 procedure times , number of coils used to treat the aneurysm , and use of adjunctive devices were much less than anticipated if conventional coil technology had been used.conclusionsthe medina coil system is a next generation coil that combines all of the familiar and expected procedural safety and technique concepts associated with conventional coils . 
 we found improved circumferential aneurysm filling , which may lead to improved long term outcomes , with fewer devices and faster operating times .