Alimentary tract foreign body ingestion is common in pediatrics, especially in neonates and toddlers . Among them, more than 80% need no intervention and the foreign body will pass out uneventfully. Only 20% call for further attention, and less than 1% require surgery . Treatments are different for different categories of foreign bodies. The wait-and-see strategy can be used in the ordinary foreign body, such as coins, jewelries, and small toys. However for the remaining 20% of patients who have fish bones, jujube pits, batteries, or magnets ingestions, active intervention is needed. Unlike other foreign bodies, ingested magnets can attract each other across bowel loops, and cause gastrointestinal wall ischemia, pressure necrosis or perforation [8-9]. Other studies also described intestinal obstruction from internal hernia and volvulus of intestine, fistula formation , and hemorrhage when the mesenteric was involved . Midget J reported a twenty-month old boy who had ingested magnets, causing intestinal necrosis and abdominal sepsis, which led to death [11-12]. Additionally, Waters AM  reported another case of death due to the hemorrhage from an esophago-aortic fistula induced by ingestion of magnets. Thus, the risk of ingestion of magnets remains higher than the ingestion of ordinary foreign bodies.
Rare-earth magnet, made from NdFeB (neodymium iron boron), a newly developed magnetic material, has a maximum magnetic energy force 5 to 10 times than that of the ordinary ferrite [12, 14-15], suggesting that the tiny rare-earth magnet can produce a huge magnetic force. It was primarily developed for industrial manufacturation such as electrical machinery, medical apparatus and instruments, in order to decrease the volume of production and enlarge its properties. However, in recent years, it has been largely used in toy production. Buckyball, made of this type of magnet and mostly consisting of 216 magnets all 5mm in size, is a colorful toy that is cheap to afford. It is also able to activate thinking skills and motivate creativity (Fig 4 A-B). Although it was developed only for people older than 14 years of age for entertainment and stress release (Fig 4 C-D), it has been given to children of all ages.
An earlier study revealed that from 2003 to 2009, 38 cases of magnetic foreign body ingestion were identified, of which 8 cases were multiple magnet ingestion, and the number continues to grow . Another investigation in 2013 reported that during 2002 and 2011, there had been more than 22,000 pediatric magnetic foreign body ingestion cases in America, and the investigation showed a 5-fold increase comparing the first and the last 2 years . In the year 2014, Buckyballs and high-powered magnets were mandatorily recalled by the consumer product safety commission in the United States, and since the recall, a significant decrease was reported in multiple mini-magnet ingestion . However, unlike the United States, our results (Fig 1 A) reveal that alimentary tract Buckyball injuries are still increasing sharply in China annually, with no trend of decline.
Our investigation showed the peak age of the children who ingested the magnets was between 1 and 3 years old, and between 6 to 11 years old (Table 1), which was consistent with De Roo AC’s study in 2013 . This may be explained by the fact that toddlers explore the world with their mouths and may accidentally swallow the Buckyballs when playing, and as a means for school aged children to boast of their bravery, as reported by one patient in this study. However, 71 of the 74 patients ingested the Buckyballs unintentionally, a finding consistent with the reports from De Roo AC  and the NASPGHAN . Other special reasons such as psychological disorders or allotriophagia [15, 16] were not found in this study. The ingestion displayed an obvious male predominance at any age period (Table 1), which was in accordance with other reports . This may be attributed to the mischievous and curious nature of boys.
Beyond the rising popularity of Buckyball, severe injuries occurred. Since it was first introduced to the market in 2009 [14, 19], the number of irreversible injuries has increased because of its powerful magnetic force . Unlike ordinary magnets, Buckyballs can attract each other even through 6 layers of intestinal walls , with an average distance of 3.5cm , and this strength increases when multiple Buckyballs are ingested . Symptoms were not specific, and were dependent on the time of presentation and location of the Buckyballs, but more than half of the patients (40/74) presented with abdominal pain. Richard Sola Jr concluded that abdominal pain was one risk factor for emergency surgery . Other complications, such as ischemia and necrosis, gastrointestinal perforation (Fig 3 A), abscess, ileus, and gastrointestinal fistula (Fig 3 B-C) also proved to be critical. Diagnosis and treatment algorithm were published by the NASPGHAN in 2012 , and patients in this study who were managed according to the algorithm attained satisfactory results.
Although treatment is of great significance, prevention is much more important. China should take measures for prevention of Buckyballs ingestion, and these suggestions listed should be followed. Firstly, on the national administration level, the production and trade of Buckyballs as well as other high-powered magnetic toys should be stopped . The serious complications that could arise should also be publicized and reinforced by various media means. Secondly, on the production level, a national policy should be implemented, targeted towards pediatric toy productions. The magnetic toy size should be enlarged and the material used to make such toys should either revert back to the ordinary magnet that has low magnetic energy product  or use a magnetic force lowered to the flux index of 50kG2 . Warning labels should be much more prominent. Thirdly, on the consumer level, parents and caregivers should be made aware about the potential risk of the toy [11, 19, 24]; and children younger than 14 years old or who have psychological disorders and allotriophagia should refrain from playing with it. Parents should monitor their children more closely when playing with magnetic toys and also educate them about the right way to play with such toys [4, 25]. Additionally, children should be taught not only about the side effects of ingesting foreign objects, but also to stop instigating harmful ingestion among their peers. When evaluating the complaints of unexplained abdominal pain, clinicians should inquire specifically about the possible ingestions that a child might have made .