
 the increased invasiveness of endoscopic procedures has resulted in a higher number of complications , such as bleeding or perforations .
although surgery still represents the mainstay in the management of these complications , new endoscopic devices have been developed to allow endoscopic treatment of fistulas , perforations , and post - polypectomy bleeding .
the ovesco over - the - scope clip ( otsc ) system ( ovesco endoscopy ag , tbingen , germany ) has shown promising results in the treatment of gastrointestinal fistulas 
 1 
 , iatrogenic perforations 
 2 
 , and bleeding 
 3 
 4 
 .
in addition , the ovesco otsc has been proposed for endoscopic full thickness resection ( eftr ) of epithelial and submucosal tumors 
 5 
 6 
 . 
 

( aponos medical , kingston , nh , united states ) , a new otsc device , has been introduced into clinical practice .
this device is conceptually similar to the ovesco system , but has some features which make it very attractive .
few studies have reported on the efficacy of this device in clinical practice 
 7 
 8 
 9 
 .
considering the emerging role of these devices in clinical practice , we decided to describe our experiences with this novel otsc system in the treatment of gastrointestinal wall defects and eftr . 

we describe the results of the treatment of 14 consecutive patients ( eight men , six women , 63???86 years ) with the padlock clip over an 18-month period in two endoscopy units .
indications for clipping were : ( i ) gastrointestinal fistulas or iatrogenic perforations , ( ii ) gastrointestinal bleeding but non - responder to thermal and/or mechanical treatments , and ( iii ) eftr of colonic lesions with non - lifting sign .
all patients provided informed consent to undergo endoscopy , and re - endoscopy was performed according to clinical follow - up . 

delivery system that consists of an applicator cap , similar to the variceal band - ligation cap ( 
 fig.?1 
 ) .
the applicator cap is available in two models : ( 1 ) standard for endoscopes with a diameter of distal tip between 9.5 and 11?mm , and ( 2 ) pro - select ? for endoscopes with a diameter of distal tip between 11.5 and 14?mm . in the standard model , the depth of the tissue chamber
model , the depth of the tissue chamber depends on the diameter of the distal tip of the scope , ranging from 8?mm for 12?mm scopes to 20?mm for 14?mm scopes . in our series , we used the standard model for gastroscopes and the pro - select ?
the padlock clip ( 
 a 
 ) and the lock - it ? delivery system ( 
 b 
 ) . 
 

the clip is preassembled in an opened position on the delivery system and it is released by a trigger cable running parallel to the scope that is connected to a handle ( 
 video 1 
 ) .
after suction of tissue into the cap to obtain adhesion to the instrument tip , the clip is released by pressing the handle which pushes the wire within the cable .
when deployed , the shape - memory effect and the high elasticity of nitinol cause the closure of the clip.?its six inner prongs penetrate and pull the tissue inward resulting in a pseudo - polyp of closed tissue ( 
 fig.?2 
 and 
 video 2 
 ) .
when performing eftr , the entrapped tissue is resected with an oval snare above the closed clip by applying cutting current ( 
 fig.?3 
 and 
 video 3 
 ) .
patients undergoing eftr have been hospitalized for one night and then discharged the day after if asymptomatic .
technical success was defined as closure of the clip and the successful resection of the trapped tissue ; specimens were classified as : ?
deep muscle resection ? ( dmr ) when a deep muscle margin was present at the vertical margin ; ?
if complete intestinal wall was included ; r1 resection if neoplastic tissue was still evident at the lateral margins , and r0 resection if no neoplastic remnant was evident . 
 
 ?
the gastric wall is going to be aspirated within the cap ( 
 b 
 ) .
the deployed padlock clip entraps the gastric wall and closes the fistula ( 
 c 
 ) . 
 
 ?
rectal depressed lesion iic with non - lifting sign . after marking the borders ( 
 a 
 ) ,
the pseudo - polyp resulting from entrapment of gastrointestinal wall into the clip ( 
 c 
 ) is resected with a snare ( 
 d 
 ) .
histology demonstrates adenoma with high grade dysplasia with clear mucosal lateral margins ( 
 e 
 ) .
the characteristics of the eight patients with fistulas , perforations , or post - polypectomy bleeding are summarized in ? 

indications for clipping were closure of gastrointestinal fistulas ( n?=?4 ) , management of iatrogenic gastrointestinal perforations ( n?=?2 ) , or hemostasis of post - polypectomy bleeding ( n?=?2 ) .
three clips were applied in the upper gastrointestinal tract ( stomach and duodenum ) and five clips in the lower gastrointestinal tract ( rectum and sigmoid colon ) . in one patient ,
the delivery system failed to release the clip into the duodenum and the wall defect was closed with two through - the - scope ( tts ) clips .
clinical success ( healing of defect or resolution of bleeding ) was achieved in all patients . in three patients , clinical follow - up
otsc , over - the - scope clip ; tts , through - the - scope . 
 in 
 table ? 2 

, we report the features of the six patients who underwent eftr . in four of the six patients , the indication was a recurrent adenoma after endoscopic mucosal resection ( emr , one in the rectum , one in the sigmoid colon , and one in the ascending colon ) or transanal endoscopic microsurgery ( tem , one patient ) ; in one patient , two ulcerated nodules were removed using two clips at ileorectal anastomosis in a patient operated for colon cancer ; and in the last case , a depressed scar in the rectum was removed ; it had resulted from previous forceps resection of a small infiltrating neuro - endocrine tumor .
, we obtained an r0 resection as defined by histology . in the case of anastomotic recurrence of adenocarcinoma
, an r1 resection was obtained , but no recurrence was seen at 6-month follow - up endoscopy .
histology demonstrated a dmr resection in three patients and a ftr in the remaining three .
follow - up ranged from 3 to 15 months and no recurrence was demonstrated either macroscopically or microscopically when the scars were biopsied .
emr , endoscopic mucosal resection ; lgd , low grade dysplasia ; hgd , high grade dysplasia ; net , neuro - endocrine tumor ; tem , transanal endoscopic microsurgery .

 the novel padlock clip is conceptually similar to the ovesco clip system , but padlock?s atypical design is likely to offer some advantages . in particular , the six inner prongs of the padlock system , which are placed in a circumferential fashion , create a firm hold of the tissue which is easily lifted within the cap without the need for further devices such as forceps or graspers .
moreover , the system allows a thorough closure as demonstrated by an ex vivo study in explanted porcine stomachs where gas inflation revealed a mean leak pressure of 68?mmhg 
 10 
 . 
  in eight out of 14 patients ,
successful otsc deployment was achieved in all but one patient , a patient with an iatrogenic perforation of the duodenum that was then successfully closed with two through - the - scope clips .
technical failure of clip release was probably due to the angulated position of the target site . in the other seven patients , the padlock clipping resulted in long - term clinical success , with definitive closure of the gastrointestinal defects and resolution of intraprocedural bleeding .
interestingly , in our series , the padlock clip was used successfully to treat two gastrointestinal fistulas after the application of an ovesco clip.?although no comparison studies between the two systems are available , padlock seems to be a reliable option in the management of gastrointestinal fistulas .
we describe for the first time the use of the padlock system to perform eftr in six patients , obtaining a ftr in 50?% of patients attempted and at least a dmr in the remaining 50?% .
we were able to achieve an r0 resection in five out of the six ( 83.3?% ) patients without any complications . in the single case in which resection was considered incomplete ,
although we could not exclude the presence of residual tumoral cells buried within the closure of the clip , no local recurrence was revealed by endoscopy with random biopsies at 6-month follow - up . 

fahndrick and sandmann 
 5 
 performed 17 eftr ( 14 in the colon ) without any complications using the standard ovesco clip , and achieved a complete resection in 70?% of patients , a ftr in 64?% and an r0 resection in 100?% .
6 
 used the dedicated ovesco device for eftr to perform resection in 25 patients ( to diagnose hirschsprung?s disease in one patient ) . in one patient ,
the progression of the scope was hindered by a diverticular stricture of the sigmoid colon ; in 20 out of 24 patients , the eftr was successful , with histologically proven ftr in 21 patients and r0 resection in 18 patients .
a grasping device was used to pull the tissue into the cap.?in our application of the padlock clip , we did not use any grasping forceps ( although it is theoretically possible ) .
in addition , the diameter of the padlock clip and the length of the cap are smaller than in the dedicated ovesco device for eftr .
these differences explain the smaller size of the specimens compared to the size of the specimens in the schmidt study 
 6 
 .
a combination of grasping and aspiration needs to be tested in a larger series and clinical trials to improve the outcomes of padlock clip - assisted eftr . 
 
the main limitations of our study were the small number of patients and the nature of the study ( non - controlled design , variable indications ) . despite these limitations
, the new padlock system seems to be an effective and safe tool , even when it is used to perform eftr .
however , further prospective clinical studies are needed to confirm its efficacy and safety , as well as to evaluate its correct use in clinical practice and explore new clinical indications .
 we describe our experience with a new over - the - scope clip ( otsc ) system ( padlock clip ? ) in the treatment of 14 patients . 
 eight of the 14 patients were treated for closure of gastrointestinal fistulas ( n?=?4 ) , iatrogenic gastrointestinal perforations ( n?=?2 ) , or hemostasis of post - polypectomy bleeding ( n?=?2 ) . 
 the site of clipping was the lower gastrointestinal tract in five patients and the upper gastrointestinal tract in three patients . 
 the clip was successfully delivered in seven out of the eight patients and clinical success was achieved in all patients . 
 endoscopic full thickness resection ( eftr ) was performed to treat six patients : four with recurrent adenoma ( n?=?4 ) , one with ulcerated nodules at ileorectal anastomosis , and one with a neuro - endocrine tumor of the rectum . 
 a complete intestinal wall resection was achieved in three of the six patients ( 50?% ) and an r0 resection in five of the six patients ( 83.3?% ) . 
 no complications related to the procedure and no recurrence at endoscopic follow - up were observed in any patient . 
 the novel padlock clip seems to be an effective and safe tool to treat gastrointestinal fistulas , perforations or post - polypectomy bleeding , and to perform eftr . 
Introduction
Case series
Discussion