endoscopic submucosal dissection ( esd ) was developed in japan for the treatment of early gastric cancer , and it is now also widely used to treat superficial esophageal cancer . since esd enables the removal of large cancerous lesions from the superficial layer of the esophagus , the indications for endoscopic dissection in guidelines for the diagnosis and treatment of esophageal cancer have been revised : the size limitation for removable lesions ( two - thirds of the circumference ) by endoscopic techniques has now been lifted . on the other hand , because esophageal stenosis is almost inevitable after the removal of subcircumferential and circumferential lesions , esophageal wall perforation during endoscopy and endoscopic balloon dilatation for the alleviation of stenosis is of particular concern in some cases . here
we present a case where conventional endoclip closure of a large perforation of the stenotic esophagus was not possible and non - surgical closure was achieved using the over - the - scope - clip ( otsc ) system ( ovesco endoscopy , gmbh , tuebingen , germany ) .
a 64-year - old woman presented with subcircumferential superficial esophageal carcinoma three - fourths the circumference of the esophagus in the upper thoracic esophagus ( fig . 
the depth of tumor invasion was evaluated as ct1a - mm by white light observation , narrow band imaging with magnifying endoscopy , and endoscopic ultrasound .
preoperative diagnosis was 0-iic , ct1a - mm , 40  mm , cn0 , cstage 0 . according to the japanese guidelines for the diagnosis and treatment of esophageal cancer , the cancer board for esophageal cancer of our hospital decided to perform esd . after obtaining informed consent
, esd was performed using an it knife nano ( kd-612 , olympus medical systems , tokyo , japan ) .
1b ) was necessary and to prevent the likely onset of stenosis , she received a local injection of triamcinolone acetonide ( 100  mg ) into the submucosa underlying the ulcer immediately after esd and was started on oral predonine therapy ( 30  mg / day ) 1  week after esd , which was tapered over a 2-month period .
histopathology findings indicated squamous cell carcinoma ( 0-iic type , t1a - mm , ly1 , v0 , hm( ) , and vm( ) ) .
additional treatment was considered because of the high risk for lymph node metastasis suggested by a positive finding of lymphatic involvement.fig . 
1endoscopic submucosal dissection ( esd ) and an ulcer showing stenosis and perforation . a superficial esophageal carcinoma about three - fourths the circumference of the esophagus located in the upper thoracic esophagus .
b immediately after esophageal endoscopic submucosal dissection ( esd ) , circumferential dissection was performed .
d large perforation due to the endoscope penetrating the wall in the upper - right side of the stenotic area endoscopic submucosal dissection ( esd ) and an ulcer showing stenosis and perforation . a superficial esophageal carcinoma about three - fourths the circumference of the esophagus located in the upper thoracic esophagus .
b immediately after esophageal endoscopic submucosal dissection ( esd ) , circumferential dissection was performed .
d large perforation due to the endoscope penetrating the wall in the upper - right side of the stenotic area two months after esd , upper endoscopy revealed a residual ulcer , but no stenosis .
distal end external diameter , 9.8  mm ) was inserted to traverse the stenosis but it penetrated the wall through to the mediastinum , leaving a perforation in the upper - right side of the stenotic area ( fig . 
. attempted closure with an endoclip ( olympus medical systems , tokyo , japan ) was unsuccessful due to the large size of the perforation and fragility of the ulcer floor .
the branches of the otsc twin grasper were released to grasp the sides of the lesion . because the perforation hole had gaping edges , i opened one branch and grasped one edge of the perforation first .
then i opened the other branch and maneuvered the grasper to the other edge and grasped it , and then retracted into the attachment to place the clip ( fig . 
the patient fasted and received antibiotics , and her only complaint was mild chest discomfort .
she did not develop fever , and both her leukocyte count and c reactive protein level were within normal range .
contrast radiography performed 5  days after the otsc procedure revealed no leakage ( fig . 
oral intake of food and fluid was resumed and 3  weeks after contrast radiography her condition was sufficiently improved . after discussing the option of surgical treatment which is standard for her with our thoracic surgeon , the patient declined surgery and opted instead for crt . because re - examination by ct revealed no metastasis , preventive crt was considered still effective , despite treatment was delayed by 1  month .
months after completing chemotherapy , the endoscope with a conventional - sized distal tip ( 9.8  mm ) could traverse the site despite the presence of minor stenosis ( fig . 
the patient reported no difficulties with nutritional intake . because mild chest discomfort continued due to the otsc
a the over - the - scope - clip ( otsc ) system showing the otsc twin grasper with its branches open outside the endoscope and two clips ( image reproduced with the permission of century medical inc . ,
b the perforation was closed by clipping the muscular layer with the otsc systemfig . 
3non - contrast radiography showing the otsc system in use ( left ) and contrast radiography showing no leakage ( right)fig . 
the endoscope could traverse the site despite the presence of minor stenosis suturing devices and perforation closure .
a the over - the - scope - clip ( otsc ) system showing the otsc twin grasper with its branches open outside the endoscope and two clips ( image reproduced with the permission of century medical inc . ,
b the perforation was closed by clipping the muscular layer with the otsc system non - contrast radiography showing the otsc system in use ( left ) and contrast radiography showing no leakage ( right ) endoscopic image taken 2 months after completing chemotherapy .
the number of cases of intraoperative perforation has increased as esophageal esd has becomes more widespread , and perforation is frequently caused by endoscopic balloon dilatation used to alleviate stenosis , a complication of endoscopic dissection of large lesions .
conservative therapy , such as perforation closure with an endoclip or placement of a nasogastric tube , is effective when the perforation is relatively small .
most perforations can typically be treated conservatively by fasting and administration of antibiotics . with a large perforation , serious mediastinitis and potentially fatal empyema
may develop and closure is therefore crucial but often difficult . the otsc system is a new endoscopic tool used for non - surgical treatment of gastrointestinal perforation , fistula , and anastomotic leak .
it is the first effective system for closing a fistula endoscopically and it is therefore attracting interest . to our knowledge , this is the first report of the otsc system being used to treat a large perforation of a stenotic lesion that developed after esophageal esd .
perforation of large lesions like this , which will likely have hard fibrotic edges and fragile surrounding tissue due to steroid treatment , occasionally need to be treated by surgical drainage or thoracotomy because of the difficulties in closing them with conventional endoclips .
the present case demonstrates that the otsc system can be used to close a large perforation of a stenotic site with good postoperative progress .
rotation of the otsc twin grasper is not perfect and the target tissue sometimes can not be grasped . also , once clips are placed , they are difficult to remove .
special care is required when employing the otsc system in organs with a narrow lumen , such as the esophagus and duodenum , because of the possible risk of stenosis . despite these limitations ,
the otsc system allows for the closure of large perforations not amenable to closure with conventional methods .
as demonstrated in the present study , the otsc system has good utility in difficult cases and thus warrants consideration .
 we report here a case of esophageal perforation made by an endoscope while treating cicatrical stenosis that developed after wide circumferential dissection of superficial esophageal carcinoma . 
 perforation closure with a conventional endoclip was difficult as the perforation was large and the surrounding tissue was fragile as a result of steroids administration for stenosis prevention . to avoid surgical intervention , we employed the over - the - scope - clip system and successfully closed the perforation . 
 the favorable outcome suggests the utility of the over - the - scope - clip system for closing perforations when conventional methods are ineffective . 
Introduction
Case report
Discussion