You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
children have a natural tendency to put any small objects into their mouth ; occasionally these objects can be ingested in the airodigestive tract ; 80% of them will be stuck in the esophagus and 20% of them will lodge in the airway . in china , no statistical data on the incidence of esophageal foreign body is available , while the american association of poison control documented 182,105 incidents of foreign body ingestion by patients younger than 20 years in 1999 [ 1 , 2 ] . in most cases ,
the majority of patients with esophageal foreign bodies are children . unlike adults , the most common pediatric esophageal foreign bodies are blunt and round objects like coins , buttons , or button batteries .
the conventional method involves removal of the foreign body under direct vision using a rigid esophagoscope under general anesthesia .
in fact , the majority of blunt pediatric esophageal foreign bodies can be removed by a nonoperative foley catheter removal . in this report
we describe our experience of first 17 cases removing blunt radiopaque esophageal foreign bodies by a foley 's catheter without fluoroscopic guidance .
we evaluated the safety and efficacy of the foley catheter technique by identifying detailed records of our first 17 cases that had undergone a foley catheter removal of blunt radiopaque foreign bodies from may 2010 to may 2013 .
the materials needed for foreign body removal include a number of 14 to 18 foley catheters , a 10  ml syringe , tongue depressor , and saline water .
additionally , pediatric direct laryngoscope , rigid esophagoscope and bronchoscope , laryngeal and bronchial forceps , suction apparatus , and oxygen supply were kept ready .
all procedures were performed in the examination room of the ent inpatient department . no patient is sedated .
radiographic confirmation is obtained to find out the presence , location , and shape of the foreign bodies .
the balloon of the catheter is tested before insertion to make sure that it inflates symmetrically .
while the catheter is inserted transorally , patients sit or are held upright position on the edge of the examination table .
children are instructed to open their mouth naturally ; in uncooperative children , a tongue depressor is put intraorally and then its two sides are bristled to prevent the child from biting the catheter .
the operator holds the catheter in his left hand and inserts it by his / her right hand , while advancing it inferiorly , he or she makes the action of swallowing and asks the child to follow .
when the catheter passed about 2025  cm , the balloon is inflated with 5  ml air or saline . before the catheter
is withdrawn , patients are placed in a prone oblique position with head slightly out of the edge of the examination table .
the balloon expands the esophageal lumen and frees the impacted foreign body ; with moderate , steady traction , it pulls the foreign body out from the esophagus ; with aid of gravity , it will usually fall out of the mouth .
if balloon extraction fails to dislodge the foreign body because of under inflation or because the balloon is not down beyond the foreign body , correction is made with an additional 13  ml air or saline in the balloon or advancing the catheter deeper .
if these corrections are unsuccessful and the foreign body will not move after 3 attempts , the technique is abandoned and the patient is referred to the rigid esophagoscopic examination under general anesthesia immediately . after successful extraction , children are monitored for 30  mins and subsequently discharged .
the patents were instructed to feed the child with a soft diet and to return immediately if the child has symptoms of chest pain , fever , dysphagia , bloody saliva , respiratory difficulty , or abdominal pain .
a total of 17 children ( 9 boys and 8 girls ) with blunt esophageal foreign bodies , aged 20 months to 10 years , were included in the study .
chest roentgenograms were obtained in all the cases to identify the shape , size , and location of the foreign body ; in all the cases , the impacted foreign body was a blunt and flat radiopaque object ; 16 of them were metallic objects ( 11 coins , 2 buttons , 1 button battery , 1 key ring , and 1 heart shaped pendant ) and one of them was a round and flat stone .
foreign body was lodged in thoracic esophagus in 7 cases , at the thoracic inlet in 6 cases and in the cervical esophagus in 4 cases .
we were successful in 16 cases ; in 12 of them the foreign body was removed in the first attempt and in 4 of them the foreign body was extracted in the second attempt by slightly increasing the volume of the balloon .
we failed in one case ; this child has a heart shaped pendant in the level of 2nd thoracic vertebra ; after 3 unsuccessful attempts , we abandoned this method and had a rigid esophagascopic examination subsequently under general anesthesia . in the examination , nothing abnormal has been identified in the whole esophageal lumen .
an immediate fluoroscopy was given in the operation room under a c arm and the foreign body was detected in the stomach .
except the child who has rigid esophagoscopy under general anesthesia , all patients were discharged well on the same day after the procedure .
rigid esophagoscopy has long been hailed as the gold standard for the removal of esophageal foreign bodies in children .
if all types of esophageal foreign bodies were considered , rigid esophagoscope is the first choice of treatment ; however , the subset of blunt and flat esophageal foreign bodies can be removed by a nonoperative method with a foley catheter .
foley catheter removal of blunt pediatric esophageal foreign bodies was first reported by bigler in 1966 .
however , similar method existed long ago , according to the descriptions of paulus aegineta , in his book  six of epitome of medicine ;  during the peak of the byzantine period , foreign bodies were extracted from the esophagus by having the patient swallow a small , dry sponge on a string , allowing it to expand in the stomach and then withdrawing the sponge .
bigler hypothesized in his original article that distension of the balloon of a foley catheter filled with contrast media inferior to the impacted foreign body would dilate the esophageal lumen , free the impaction , and allow safe extraction of the blunt and flat foreign bodies under fluoroscopic monitoring .
because of no need for anesthesia , removal of blunt esophageal foreign bodies by this method has become a relatively common problem shared by radiologists , pediatric surgeons , otolaryngologists , emergency department physicians , and gastroenterologists . in real practice ,
certain modifications were made by some scholars , like inserting the catheter transorally , replacing contrast media with saline water or air , and performing the procedure without fluoroscopy [ 58 ] . by these modifications ,
the whole procedure becomes simpler , the radioactive contaminations can be avoided and the patients and their parents ' anxieties also can be eliminated .
we used this modified technique to remove blunt esophageal foreign bodies and succeeded in 16 out of 17 cases .
the main critical concern about foley catheter removal of esophageal foreign bodies was safety , because it carries certain blindness , resulting in esophageal perforation and airway compromise .
however , the incidence of all complications of foley catheter removal of blunt foreign bodies has been consistently low in all published series .
the largest survey of pediatric radiologists by campbell and condon included 2500 procedures with only one serious but reversible hypoxic episode .
the only one case of death in the literature till now , caused by aspiration of a coin during foley catheter removal , was reported in a survey by hawkins . at the same time he reported five patients who died while undergoing esophagoscopic removal of a coin under general anesthesia .
after 10 years of editing many articles on the pros and cons of foley catheter removal , berdon found that great differences in opinion existed among practitioners .
he concluded that  those who use the technique will continue to use it and feel comfortable : those that are not sold on the technique will remain unsold  . a review of 415 cases by schunk et al .
found minor complications like epistaxis and vomiting in 8 ( 2% ) patients and 4 ( 1% ) patients who had the major complications of mediastinitis , transient airway compromise , respiratory distress with uneventful recovery , and esophageal laceration requiring surgery .
two of these complications occurred in patients with nonradiopaque foreign bodies , the third complication was caused by an impaction of unknown duration , and the fourth occurred after multiple attempts including simultaneous use of two foley catheters .
actually , all the 4 major complications above can totally be prevented by careful patient selection and standard performance .
foley catheter method was contraindicated to the former three cases ; the fourth case was entirely the result of improper handling .
all of these show that , if performed under strict inclusion criteria and standard procedure , foley catheter removal can be the first choice of treatment for blunt and flat esophageal foreign bodies .
advantages of foley catheter method including that they are ( 1 ) easy to perform and learn ; ( 2 ) safe : complication rate is as low as 02% and can omit the potential complications of rigid esophagoscopy ; ( 3 ) efficient : success rat is 85100% ; ( 4 ) rapid : it rarely takes more than 20 minutes ; ( 5 ) having no need for anesthesia : it can prevent anesthesia related complications ; ( 6 ) haveing the possibility to be performed on outpatient basis . because it can obviate the need for anesthesia and hospitalization , this method is highly cost effective . in current health expense system in our region ,
the mean cost for foley catheter extraction without fluoroscopy on an outpatient basis is less than 200rmb ( cost for foreign body removal is 150rmb+cost for material is 35rmb ) ; rigid esophagoscopy under general anesthesia costs at least 4000rmb , which translates into savings of 3800rmb . to ensure safety and to improve success rate ,
firstly , this method should be administered only for blunt and flat radioopaque foreign bodies .
some scholars suggest that blunt non radiopaque foreign bodies also should be included in the indications of this method ; however , it is not easy to estimate the shape and size of this type of foreign bodies precisely , so they are preferably removed under rigid esophagoscopy
. the duration of impaction should not be longer than 72 hours , because success decreased to 50% if the duration was longer than 72 hours .
button batteries are an exception ; because the potential voltage burn and esophageal erosion can occur as early as 4 hours after ingestion , they should be removed endoscopically as early as possible . however
, if the impaction is of less than 2-hour duration , foley catheter extraction is an acceptable alternative [ 13 , 14 ] . in this series
we have a 4-year - old boy who had swallowed a button battery 30  mins earlier ; the battery was removed by a foley catheter in one attempt uneventfully .
this method is contraindicated in the following situations : ( 1 ) if the foreign body has been impacted for more than 72 hours , ( 2 ) if the esophagus was totally obstructed by impacted foreign body , ( 3 ) if we found suspected esophageal perforation , ( 4 ) if we found multiple foreign body impaction , ( 5 ) if patient has sign of airway distress , ( 6 ) if we found sharp edged foreign bodies , ( 7 ) and if we found button batteries that impacted for more than 2 hours .
some authors noted that children younger than 1.5 years seem to be at the highest risk for esophageal edema and failure of foley catheter extraction .
this may be due to the smaller caliber of the esophagus , the softer trachea that can be compressed easily , as well as the delayed diagnosis in nonverbal , and uncooperative infants .
our youngest patient was a 20-month - old child who had swallowed a flat and round stone for 4 hours ; the stone was removed in one attempt with a foley catheter .
secondly , during the procedure , it is strongly recommended to maneuver the child into a prone oblique position while withdrawing the catheter to eliminate the freed foreign body to advance toward stomach or to the airway by gravity
overdistention should be avoided . at first , inflate the balloon with 4 - 5  ml saline , if the balloon slips past the impacted object , try again with an additional 13  ml saline in the balloon . stop inflation if the patient feels pain .
if the impacted foreign body can not be removed after 3 attempts , this method should be abandoned and the child should be referred to rigid esophagoscopy under general anesthesia .
after 3 unsuccessful attempts in one of our cases , without obtaining another chest x - ray film , we have esophagascopic examination under general anesthesia and did not find anything abnormal in the whole esophageal lumen ; subsequently we have a fluoroscopy in the operating room under a c arm and found that the impacted object was already in the stomach .
so , before esophagascopic examination , it is very important to have another chest roentgenograms to see if the object moved or passed to the stomach . in
up to 16% patients , the foreign body will advance into the stomach ; this is not seen as a failure given that safe passage throughout the rest of the alimentary tract can usually be assumed .
thirdly , when performing this technique , it is preferable to keep pediatric laryngoscope , rigid esophagoscope and bronchoscope , suction apparatus , and oxygen supply readily available , so that we may utilize them in critical moments .
we have never required any of this equipment in all of our cases ; however , we think if conditions permit , this equipment will never be the fifth wheel of the coaching .
objective . to discuss the safety and efficacy of foley catheter removal of blunt pediatric esophageal foreign bodies . methods . analyzing our first 17 cases of pediatric esophageal foreign bodies removed by foley catheter method in respect of the efficacy , removal methods , and complications . 
 we also reviewed related literature and discussed the background , current status , and technical matters that need attention of this method . 
 results . in three - year period between may 2010 and may 2013 , in 16 out of 17 children blunt radiopaque foreign bodies impacted in the esophagus were successfully removed by a foley catheter . 
 there were no complications . 
 in one patient , the foreign body was advanced into stomach and came out with stool 2 days later . 
 conclusions . 
 the technique is safe , rapid , and cost - effective procedure and applicable for blunt , flat foreign bodies impacted in the esophagus .