the short double - balloon enteroscope ( dbe ) is considered a useful device for endoscopic retrograde cholangiopancreatography ( ercp ) in patients with surgically altered anatomies.1 one reason for this is that the short length of the scope allows many conventional ercp accessories to be used , unlike the long dbe
. however , the narrow working channel of the scope , with a 2.8-mm diameter , limits the procedures and treatments that can be performed . on the other hand ,
a useful overtube - assisted technique with the long single - balloon enteroscope replaced by a conventional forward - viewing upper endoscope , which enables the use of conventional accessories after reaching the target site , was reported.2 however , the scope exchange can be difficult , especially if the overtube collapses due to an acute angulated site,3 and the diameter of the working channel of currently available upper scopes is only 2.8-mm . a newly developed short dbe ( ei-580bt ; fujifilm , tokyo , japan ) , whose working channel is enlarged to 3.2 mm in diameter ( figs 1 and 2 ) , represents a novel innovation for patients with surgically altered anatomies .
herein , we report three patients in whom this new scope contributed to efficient technique and ideal treatment for stent placement .
a 37-year - old woman who had undergone living donor liver transplantation with right lobe graft for congenital biliary atresia was admitted for cholangitis due to benign recurrent biliary obstruction .
3a ) , and cholangiogram showed benign strictures of the bile duct ( b6 , b7 , and b8 ) and bilioenteric anastomotic stricture ( fig .
3b ) . we planned to place as many plastic stents as possible in order to achieve sufficient dilation of these strictures .
first , 0.035-inch ( revowave ; piolax , kanagawa , japan ) and 0.025-inch ( visiglide2 ; olympus , tokyo , japan ) guidewires were inserted in b7 and b6 , respectively ( fig .
while maintaining a 0.025-inch guidewire in b6 , a 7-f plastic stent ( through pass ; gadelius , tokyo , japan ) was smoothly advanced using a 0.035-inch guidewire , and was placed into b7 ( fig .
secondly , the 0.035-inch guidewire was reinserted in b6 , and a second 7-f plastic stent ( through pass ; gadelius ) was placed into b6 using the guidewire , still maintaining the 0.025-inch guidewire in place .
similarly , the 0.035-inch guidewire was reinserted in b8 , and a third 7-f plastic stent ( through pass ; gadelius ) was placed into b8 ( fig .
3e ) . finally , a fourth 7-f plastic stent ( through pass ; gadelius ) was successfully placed into b6 using the 0.025-inch guidewire that was initially inserted ( fig .
three months later , these four plastic stents were exchanged safely and accurately by the same methods due to persistent biliary strictures , which were improved but still present ( table 1 ) .
a 78-year - old man who had received chemotherapy for postoperative recurrence of gastric cancer in the intra - abdominal lymph nodes and lung after distal gastrectomy with roux - en - y reconstruction was admitted for jaundice .
computed tomography imaging revealed distal malignant biliary obstruction ( mbo ) due to enlarged lymph nodes .
4a ) , biliary cannulation was successfully performed ; a cholangiogram showed a 15-mm long distal biliary obstruction ( fig .
4b ) . following endoscopic sphincterotomy using a sphincterotome ( rotacut ; medi - globe gmbh , achenmhle , germany ) , a partially covered self - expandable metal stent ( csems ) with a delivery system of 8.5-f diameter and 194-cm working length ( wallflex biliary rx stent ; boston scientific , natick , ma , usa ; 10 mm60 mm ) was successfully deployed ( fig .
after resolution of jaundice , chemotherapy was resumed , and no recurrent biliary obstruction occurred for 13 months ( table 1 ) . a 59-year - old woman who had undergone total gastrectomy with roux - en - y due to gastric cancer was admitted for abdominal pain due to cancer recurrence .
computed tomography imaging revealed malignant afferent - loop obstruction , involving the third portion of the duodenum .
therefore , duodenal stent placement was attempted as palliative therapy using the newly developed short dbe . after reaching the lesion ( fig .
5a ) , small - bowel enema showed stenosis of approximately 40-mm in length ( fig .
5b ) . then , an uncovered self - expandable metal stent ( usems ) ( niti - s d pyloric / duodenal uncovered stent ; taewoong medical , gimpo , korea ; 18-mm in diameter , 6-cm in length ) with a delivery system of 9-f diameter and 220-cm working length was smoothly advanced via the through - the - scope technique , and placed correctly and safely under endoscopic view and fluoroscopic guidance using the new scope ( fig . 5c 
a 37-year - old woman who had undergone living donor liver transplantation with right lobe graft for congenital biliary atresia was admitted for cholangitis due to benign recurrent biliary obstruction .
3a ) , and cholangiogram showed benign strictures of the bile duct ( b6 , b7 , and b8 ) and bilioenteric anastomotic stricture ( fig .
3b ) . we planned to place as many plastic stents as possible in order to achieve sufficient dilation of these strictures .
first , 0.035-inch ( revowave ; piolax , kanagawa , japan ) and 0.025-inch ( visiglide2 ; olympus , tokyo , japan ) guidewires were inserted in b7 and b6 , respectively ( fig .
while maintaining a 0.025-inch guidewire in b6 , a 7-f plastic stent ( through pass ; gadelius , tokyo , japan ) was smoothly advanced using a 0.035-inch guidewire , and was placed into b7 ( fig .
secondly , the 0.035-inch guidewire was reinserted in b6 , and a second 7-f plastic stent ( through pass ; gadelius ) was placed into b6 using the guidewire , still maintaining the 0.025-inch guidewire in place .
similarly , the 0.035-inch guidewire was reinserted in b8 , and a third 7-f plastic stent ( through pass ; gadelius ) was placed into b8 ( fig .
3e ) . finally , a fourth 7-f plastic stent ( through pass ; gadelius ) was successfully placed into b6 using the 0.025-inch guidewire that was initially inserted ( fig .
three months later , these four plastic stents were exchanged safely and accurately by the same methods due to persistent biliary strictures , which were improved but still present ( table 1 ) .
a 78-year - old man who had received chemotherapy for postoperative recurrence of gastric cancer in the intra - abdominal lymph nodes and lung after distal gastrectomy with roux - en - y reconstruction was admitted for jaundice .
computed tomography imaging revealed distal malignant biliary obstruction ( mbo ) due to enlarged lymph nodes .
4a ) , biliary cannulation was successfully performed ; a cholangiogram showed a 15-mm long distal biliary obstruction ( fig .
4b ) . following endoscopic sphincterotomy using a sphincterotome ( rotacut ; medi - globe gmbh , achenmhle , germany ) , a partially covered self - expandable metal stent ( csems ) with a delivery system of 8.5-f diameter and 194-cm working length ( wallflex biliary rx stent ; boston scientific , natick , ma , usa ; 10 mm60 mm ) was successfully deployed ( fig .
after resolution of jaundice , chemotherapy was resumed , and no recurrent biliary obstruction occurred for 13 months ( table 1 ) .
a 59-year - old woman who had undergone total gastrectomy with roux - en - y due to gastric cancer was admitted for abdominal pain due to cancer recurrence .
computed tomography imaging revealed malignant afferent - loop obstruction , involving the third portion of the duodenum .
therefore , duodenal stent placement was attempted as palliative therapy using the newly developed short dbe . after reaching the lesion ( fig .
5a ) , small - bowel enema showed stenosis of approximately 40-mm in length ( fig .
, an uncovered self - expandable metal stent ( usems ) ( niti - s d pyloric / duodenal uncovered stent ; taewoong medical , gimpo , korea ; 18-mm in diameter , 6-cm in length ) with a delivery system of 9-f diameter and 220-cm working length was smoothly advanced via the through - the - scope technique , and placed correctly and safely under endoscopic view and fluoroscopic guidance using the new scope ( fig . 5c 
this newly developed short dbe with an enlarged working channel represents technological innovation in endoscopic stent placement for patients with surgically altered anatomies ; the double guidewire technique was efficient and effective for multiple stent placement .
csems placement , which represents standard treatment for mbo , and usems placement , as palliative treatment for malignant afferent - loop obstruction , were both performed in a technologically sound and safe manner .
first , we demonstrated multiple 7-f plastic stent placements with the double guidewire technique using standard guidewires , such as 0.035-inch and 0.025-inch guidewires , employing the newly developed short dbe .
the conventional short dbe with a small , 2.8-mm working channel does not allow placement of a 7-f stent while also maintaining a second standard guidewire in place . therefore , we would need to perform biliary stenting one by one : a repeated process consisting of targeting the bile duct using a standard guidewire and placing a plastic stent within the duct
. however , this impractical procedure carries a potential risk with the increasing number of stents placed : a greater number of stents would make it more difficult to identify and target the bile duct using the guidewire .
previously , we reported that a 0.018-inch guidewire was useful in the double guidewire technique as a landmark guidewire when performing partial stent - in - stent placement of metallic stents using conventional short dbe.4 however , a 0.018-inch guidewire is inadequate for biliary stenting , because of its reduced stiffness .
the ability to maintain a 0.025-inch guidewire is more useful and reasonable for definitive and efficient biliary stent placement . in the second case
, we describe a patient with postoperative distal mbo due to lymph node metastases , in whom the newly developed short dbe contributed to transpapillary csems placement , by through - the - scope methods .
csems is useful for the treatment of distal mbo , because of its long - term patency compared with usems.5,6 however , although successful scope insertion and cholangiogram were achieved using a conventional short dbe , a csems that can be placed using the short dbe with a small working channel was unavailable ; therefore , an usems or plastic stent must be selected for distal mbo .
the availability of not only usems but also csems is critically important from a clinical perspective , because it allows postoperative patients with distal mbo to receive the standard treatment , similar to that used in patients with normal anatomies .
thirdly , we report a postoperative patient with malignant afferent - loop obstruction , in whom the new scope contributed to the placement of the usems , designed as a duodenal stent , by through - the - scope methods .
conventional dbe could never allow gastrointestinal metal stent placement for malignant gastrointestinal obstruction such as an afferent - loop obstruction , because of the narrow working channel of the scope .
therefore , one common practice is to insert the conventional dbe to the stricture and subsequently remove it , leaving the overtube ; the self - expandable metal stent is then placed through the over - tube under fluoroscopic guidance.7,8 this technique is useful , but stent placement using the new scope , and the through - the - scope method , as in our case , is more ideal for achieving correct and safe stent placement.9 the wider working channel of this new scope also facilitates smoother accessory insertion and high suction performance , which can reduce procedure time and stress on endoscopists . in addition , this new scope allows for improved and easier scope insertion , by producing gradual stiffness with advanced force transmission for better stability and adaptive bending .
additionally , the smaller turning radius allows for improved viewing of the target site and a better environment for treatment .
this scope is expected to be useful in improving the ability to obtain successful diagnosis and therapy for various digestive diseases in patients with surgically altered anatomies .
this newly developed short dbe brings about technological innovation in stent placement , and therefore standard , efficient , and safe treatment can be performed even in patients with surgically altered anatomies .
 a newly developed short double - balloon enteroscope with a working channel enlarged to a diameter of 3.2 mm is a novel innovation in stent placement for patients with surgically altered anatomies . 
 herein , we report three patients in whom this new scope contributed to an efficient technique and ideal treatment . in the first case , 
 the double guidewire technique was efficient and effective for multiple stent placements . in the second case , covered self - expandable metal stent ( sems ) placement , which is the standard treatment for malignant biliary obstruction , 
 could be performed in a technologically sound and safe manner . in the third case , 
 sems placement was performed as palliative treatment for malignant afferent - loop obstruction ; this procedure could be performed soundly and safely using the through - the - scope technique . 
 the wider working channel of this new scope also facilitates a smoother accessory insertion and high suction performance , which reduces procedure time and stress on endoscopists . 
 furthermore , this new scope , which has advanced force transmission , adaptive bending , and a smaller turning radius , is expected to be highly successful in both diagnosis and therapy for various digestive diseases in patients with surgically altered anatomies . 
INTRODUCTION
CASE REPORTS
1. Case 1
2. Case 2
3. Case 3
DISCUSSION