Magnetic Foreign Body Injuries: A Large Pediatric Hospital Experience Matt Strickland, MD, BASc1,2, Daniel Rosenfield, MD1,3, and Annie Fecteau, MDCM, MSc1,2 Objective To examine trends in magnet-related injuries and hypothesize that changes are a result of new neodymium-iron-boron magnets that are smaller, stronger, and commonly sold in sets.
Study design In this retrospective chart review, we searched our institution’s electronic patient record for patients less than 18 years old who were diagnosed with magnetic foreign body ingestion between 2002 and 2012. Cases were analyzed for patient, magnetic foreign body, and management characteristics. Incidence rates and case characteristics were compared between the first 8 years of the study period and the last 3. Results We identified 94 patients who met our search criteria. Of confirmed ingestions, the median age was 4.5 years and 65% were male. The incidence of visits increased between the 2002-2009 period and the 20102012 period by a factor of 2.94 (95% CI, 1.84-4.70), whereas the incidence of injuries involving multiple magnets increased by a factor of 8.40 (95% CI, 3.44-20.56). The volume of the magnets decreased from 878.6 mm3 to 259.8 mm3. Six cases required surgical removal of the magnets because of intra-abdominal sepsis or concern for imminent bowel perforation. Conclusions Since 2002, there has been a significant increase in the incidence of magnetic foreign body injuries. These injuries have increasingly involved multiple, smaller magnets and required operative intervention. (J Pediatr 2014;-:---).
P
ediatric magnet ingestions have received increasing attention over the past 10 years. Although most smooth, ingested foreign bodies pass innocuously through the gastrointestinal tract,1 multiple magnets pose the unique danger of being able to attract each other through different loops of bowel, arresting their movement, and potentially causing mural pressure necrosis. This can lead to bowel perforation, fistula formation, volvulus, obstruction, intra-abdominal sepsis, and death.1-6 With the advent of stronger neodymium-iron-boron magnets and their inclusion as part of children’s toys, jewelry, and desk toys, there has been a documented increase7-9 in the number of cases resulting in serious morbidity6 and in rare cases, mortality.4,5 Injury surveillance data from the US,4 Canada,10 and Australia11 suggested as early as 2006 that this was a developing trend. More recently, 2 groups7,8 examined data from the US National Electronic Injury Surveillance System and showed that the rate of magnet-related injury had increased dramatically over the period from 2002 to 2011. One large, urban pediatric hospital in the US has published its experience and demonstrated an apparent increase in the number of ingestions and an increasing proportion involving multiple magnets.12 The purpose of our study was to examine the epidemiology and temporal trends of magnet-related injury at a large, Canadian pediatric hospital. Where possible, we aimed to examine the type and number of magnets involved to seek evidence on how shifting magnet technology was involved in this evolving injury pattern. We hypothesized that there would have been a significant increase in magnet-related injury from 2002-2012, with a detectable shift toward smaller magnets and ingestions involving multiple magnets. With this, we expected to find an increase in the morbidity associated with these ingestions.
Methods We performed a retrospective study of all emergency department (ED) visits between April 1, 2002 and December 31, 2012, to a single urban tertiary care pediatric ED with an average annual volume of approximately 55 000 visits over the study period. This included patients referred by community physicians directly to our gastrointestinal, otolaryngology, and general surgery services via the ED. (In these cases, the patients are not assessed by the emergency staff, but are held in the ED until assessed by the consultant services.) Our hospital serves as 1 of 4 acute-care pediatric hospitals in Ontario, Canada, a province of 13.5 million people. It acts as a referral center for all pediatric subspecialties as well as being the local hospital for children living in the surrounding urban neighborhoods. We identified cases by searching through all ED visits with International Classification of Diseases, 10th revision (ICD-10) codes corresponding to foreign From the Hospital for Sick Children, Division of General 1
2
Surgery, and 3Department of Pediatrics. University of Toronto, Toronto, Ontario, Canada
ED ICD-10 IRR
Emergency department International Classification of Diseases,10th revision Incidence rate ratio
The authors declare no conflicts of interest. 0022-3476/$ - see front matter. Copyright ª 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jpeds.2014.04.002
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bodies in the alimentary tract (T18.x). In the province of Ontario, all hospital diagnoses and procedures are labeled and collected using ICD-10 codes for administrative purposes. We also reviewed the administrative database of consultations performed by the general surgery service to assure no cases were missed. All charts were reviewed by authors M.S. or D.R. to identify patients who met the inclusion criteria. This criteria included all patients under 18 years of age suspected of or confirmed to have a magnet ingestion via parental report, diagnostic imaging, or pathology report. Children presenting on multiple occasions with respect to the same ingestion event were abstracted as a single case. We did not include patients who were seen with a foreign body in the external eye, ear, respiratory tract, or genitourinary tract. We chose to limit our scope to the alimentary tract because the majority of complications reported with magnet ingestions arise from perforations and fistulae of the stomach, small bowel, and colon.6 We collected data on patient demographics; type of imaging obtained and findings; patient disposition; procedures or operations; length of hospital stay; and specialist consults. For all encounters where diagnostic imaging was available, 2 observers independently examined the films to assess for number, shape, and approximate size (using the linear measurement tool of our digital image viewing software [GE Centricity RA1000 Workstation v 3.2; GE, Little Chalfont, United Kingdom]) of
Table I. Summary of patient demographics, care received, and magnet characteristics Alimentary tract magnet ED presentations Confirmed magnets (%)* Ingestions Anal insertions Suspected magnet ingestion (%)† Multiple magnets (% of confirmed ingestion) Magnets with other metallic FB (% of confirmed ingestion) Sex (% of confirmed ingestion) M Female Age in years, median Minimum Maximum Developmental disabilities (% of confirmed ingestion) Autism Global developmental delay Diagnostic tests (%) Imaging Blood work Procedures (% of confirmed ingestion) Esophagogastroduodenoscopy Colonoscopy Rigid sigmoidoscopy Rigid esophagoscopy Surgical removal Shape of magnet assessed (% of confirmed ingestion) Spherical Cylindrical Other
94 75 (80) 72 3 19 (20) 30 (42) 2 (3) 47 (65) 25 (35) 4.6 1.1 13.1 4 (5) 3 (4) 1 (1)
the magnets. Magnet volume was calculated for foreign bodies where orthogonal views allowed both observers to confidently assess the shape and obtain necessary measurements to calculate the approximate volume. To examine whether a difference in magnet-injury epidemiology might be attributable to the widespread introduction of small spherical magnet sets in 2009,13,14 we compared the first 8 years (2002-2009, period 1) of the study period to the last 3 years (2010-2012, period 2). We used our institution’s annually reported number of ED visits to create magnet-related injury rates. We used Poisson regression as well as 2-tailed t tests with unequal variance to compare incidence rates and magnet characteristics between these 2 time periods. The study was approved by the hospital’s Research Ethics Board.
Results Between April 1, 2002 and December 31, 2012, a total of 2722 patient visits were classified as injury because of alimentary tract foreign bodies. Upon reviewing these files, 94 unique children were identified as meeting our inclusion criteria. In 75, magnets were confirmed after removal or by a combination of history of magnet ingestion and at least one radioopaque foreign body seen on medical imaging. The remaining 19 patients presented because of suspicion of ingestion, but either no magnets were found on imaging or no further workup was conducted. Demographic data are summarized in Table I. The incidence rate ratio (IRR) of magnet-related injuries after the introduction of the desk toys was 2.94 (95% CI, 1.84-4.70). The IRR for magnet-related injuries with multiple magnets was 8.4 (95% CI, 3.44-20.56). The year-to-year IRR over the entire study period was 1.08 (95% CI, 0.61-1.55) for magnet-related injuries and 2.13 (95% CI, 1.23-3.02) for cases involving multiple magnets. Incidence over time is illustrated in the Figure.
72 (100) 11 (15) 7 (10) 1 (1) 1 (1) 1 (1) 6 (8) 66 (88) 30 (46) 28 (42) 8 (12)
M, male. *Either confirmed at time of removal or by a history of suspected or witnessed magnet ingestion and presence of radio-opaque FB on imaging. †Presented with history of magnet ingestion but no workup was conducted or imaging failed to confirm presence of radio-opaque FB.
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Figure. Incidence (per 100 000 ED visits) of alimentary tract magnet injuries over time. Strickland, Rosenfield, and Fecteau
- 2014
ORIGINAL ARTICLES
The median approximated volume of individual magnets, as determined from dimensions obtained on radiography, went from 878.6 mm3 in period 1 to 259.8 mm3 in period 2 (P = .04). Median age of patients at presentation did not increase significantly over the course of the study period (4.5 vs 4.7, P = .3). Six surgical interventions (Table II) were performed for intra-abdominal sepsis (defined by clinical criteria, including tachycardia, pyrexia, and/or worsening peritonitis) secondary to gastrointestinal perforation. All 6 of these cases occurred in the last 2 years of our study period (2011-2012) and are summarized in Table II. Furthermore, there were 10 endoscopic removals of magnets, all in 2010 and later.
Discussion This single institutional series identifies a significant increase in the incidence rate of multiple magnet-related injuries between 2002 and 2012. More concerning than the simple rise in incidence, however, is the increased number of high-risk injuries featuring multiple, smaller magnets. These changes are in keeping with the documented technological shift from ferrite magnets to neodymium-iron-boron magnets that are approximately 10-20 times more powerful and often sold as sets of 125 or 216 spheres approximately 5 mm in diameter or as part of toy construction kits. The increase in injuries that we report has developed despite new magnetspecific toy standards, labeling requirements, product recalls, and safety advisories4,15,16 all issued in the past 10 years as dangers were identified.
Our data demonstrate a further important trend in the morbidity of magnets in the alimentary tract. All 16 cases requiring operative or endoscopic intervention occurred during the last 3 years of the study period. It is worth reporting that of the children requiring surgical intervention, all 6 were males. This finding is different from other case series in the literature, where the sex demographics of those requiring operations reflect that of the overall ingesting population. Although we did not have any deaths in this series, a number of our patients did require laparotomies and some required small bowel resections for intra-abdominal sepsis. Shortly after the end of our study period, Health Canada, the national department responsible for public health, issued a recall of neodymium-iron-boron magnet sets marketed as desk toys.17 This was escalated to the country’s first-ever mandatory product recall after one manufacturer failed to comply.14 Although curbing future supply will likely have a protective effect against further magnet-related injuries, there are hundreds of thousands of magnet sets already in the homes of Canadian consumers and these pose an ongoing threat to children.18 Magnets for refrigerators, jewelry, and other uses are not covered as part of the recall and online sales of similar toys are difficult to police. Therefore, in the near future, education for physicians and parents on the health dangers of magnets will be an important pillar in the prevention of further injuries. Recently published algorithms outline how primary care physicians and specialists can work together collaboratively to manage these patients.19 Our study had limitations. It was a retrospective chart review based on ICD-coded ED visits and an administrative
Table II. Summary of cases managed surgically Year
Age
Sex
No. of magnets
LOS (days)
Operation
2011
3 y 10 m
M
5
2
2011
3 y 2 mo
M
3
4
2011
3 y 4 mo
M
17
8
2012
12 y 1 mo
M
3
8
Laparoscopy with exteriorization of appendix, enterotomy via appendix, removal of magnets from caecum, appendectomy. Laparoscopy with exteriorization of small bowel, enterotomy, removal of magnets, and repair of small bowel fistula. Laparoscopy converted to laparotomy with enterotomy and gastrotomy for removal of magnets, small bowel resection (3.0 cm), side-to-side stapled anastomosis, and primary repair of perforations. Laparoscopy, converted to laparotomy with enterotomy, removal of FB from small bowel, and primary repair.
2012
3 y 0 mo
M
4
8
2012
3 y 3 mo
M
3
4
Laparoscopy with exteriorization of small bowel, enterotomy, removal of magnets, and primary repair of 8 perforations. Laparoscopy with exteriorization of small bowel, enterotomy, extraction of magnets, resection of small bowel (4.5 cm), and end-to-end anastomosis.
Complications None.
None.
Ileus. Postoperative fever. Returned with superficial surgical site infection.
Returned within 6 mo with small bowel obstruction. Laparotomy with, lysis of adhesions. Postoperative fever.
None.
LOS, length of stay.
Magnetic Foreign Body Injuries: A Large Pediatric Hospital Experience
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database and, as such, cases may have been missed due to improper coding. As a tertiary referral center for pediatric subspecialty care, patients are referred from across the province with high care requirements. Our rates of magnetrelated injuries requiring procedures for removal are thus likely exaggerated compared with the province-wide incidence among pediatric ED visits. Even before the recent federal government action against magnets, several lower-profile warnings, news stories, and toy recalls had elevated public awareness of the dangers of magnet ingestion. This may have driven more parents to seek medical care for alimentary tract magnets in the latter part of our study period. Increasing awareness amongst physicians may also have decreased the threshold to perform endoscopy for magnet retrieval, inflating the number of interventions in the latter part of our study period. In addition, early in the study, many of the balls in children’s ball-and-rod construction sets were not actually magnetic, relying on magnets in the rods instead. Some of the confirmed, radio-opaque ingested spheres reported by parents as magnetic may have simply been the inert ball component of these sets. Our institutional experience from 2002-2012 demonstrates a recent rise in alimentary tract magnets and incidence of multiple magnet ingestion. We further showed a statistically significant decrease in the size of implicated magnets and a trend toward greater morbidity. This data spans a greater than 10-year period before the Canadian government placed heavy restrictions on the sale of small, powerful magnet sets. Given the existing number of magnet sets as well as other, uncontrolled sources of magnets already in homes and schools, education of parents, teachers, and primary care physicians will be important to prevent further harm. n Submitted for publication Nov 13, 2013; last revision received Feb 6, 2014; accepted Apr 2, 2014. Reprint requests: Matt Strickland, MD, BASc, Division of General Surgery, c/o The Hospital for Sick Children, 555 University Ave, Rm 1526, Toronto, Ontario, Canada M5G 1X8. E-mail: [email protected]
References 1. Tavares MM, Saladino RA, Gaines BA, Manole MD. Prevalence, Clinical Features and Management of Pediatric Magnetic Foreign Body Ingestions. J Emerg Med 2013;44:261-8. 2. Nui A, Hirama T, Katsuramaki T, Maeda T, Meguro M, Nagayama M, et al. An intestinal volvulus caused by multiple magnet ingestion: an unexpected risk in children. J Pediatr Surg 2005;40:e9-11. 3. Rosenfield D, Strickland M, Fecteau A. Cases: magnet ingestion by a 3year-old boy. CMAJ 2013;185:972-4.
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Vol. -, No. 4. US Consumer Product Safety Commission. Child’s death prompts replacement program of magnet building sets. 2006 Mar 31; Release #06–127. Available at: http://www.cpsc.gov/en/Recalls/2006/ChildsDeath-Prompts-Replacement-Program-of-Magnetic-Building-Sets. Accessed May 1, 2014. 5. Consumers’ Federation of Australia. ACT: ban on small high powered magnets. 2012 Aug 30. Available at: http://consumersfederation.org. au/act-ban-on-small-high-powered-magnets/. Accessed May 1, 2014. 6. Naji H, Isacson D, Svensson J, Wester T. Bowel injuries caused by ingestion of multiple magnets in children: a growing hazard. Pediatr Surg Int 2012;367-74. 7. Silverman J, Brown J, Willis M, Ebel B. Increase in pediatric magnetrelated foreign bodies requiring emergency care. Ann Emerg Med 2013;62:604-8. 8. Abbas M, Oliva-Hemker M, Choi J, Lustik M, Gilger M, Noel A, et al. Magnet ingestions in children presenting to US emergency departments, 2002-2011. J Pediatr Gastroenterol Nutr 2013;57:18-22. 9. Brown JC, Otjen JP, Drugas GT. Magnet Ingestions in Children: An Emerging Problem. Washington, DC: Pediatric Academic Societies’ Annual Meeting; May, 2012. 10. Canadian Hospitals Injury Reporting and Prevention Program. CHIRPP injury report: injuries associated with magnets. Public Health Agency of Canada. 2006. Available at: http://www.phac-aspc.gc.ca/injury-bles/ chirpp/injrep-rapbles/magnets-aimants07-eng.php. Accessed May 1, 2014. 11. Swaminathan M, Baker R, Scott D. Injuries due to magnets in children: an emerging hazard. Queensland Injury Surveillance Unit Injury Bulletin. 2010;109. Available at: http://www.qisu.org.au/ ModCoreFilesUploaded/Bulletin109259.pdf. Accessed May 1, 2014. 12. Agbo C, Lee L, Chian V, Landscahft A, Kimia T, Monuteaux M, et al. Magnet-related injury rates in children. J Pediatr Gastroenterol Nutr 2013;57:14-7. 13. Stevenson T. Safety standard for magnet sets. Fed Regist 2012;77:53781801. 14. Health Canada. Health Canada orders NeoMagnetic Gadgets Inc. to recall magnet sets. Health Canada Consumer Product Recall. 2013 Jun 20;RA-34263. Available at: http://healthycanadians.gc.ca/recall-alertrappel-avis/hc-sc/2013/34263r-eng.php. Accessed May 1, 2014. 15. Health Canada. MAGZ Magzoid Magnetic Construction System. Health Canada Consumer Product Recall. 2009 Sep 17;RA-500002103. Available at: http://www.healthycanadians.gc.ca/recall-alert-rappel-avis/hcsc/2009/12762r-eng.php. Accessed May 1, 2014. 16. Health Canada. Health Canada reminds Canadians of the dangers of small magnets. 2008 Sep 15;RA-110002394. Available at: http://www. healthycanadians.gc.ca/recall-alert-rappel-avis/hc-sc/2008/13252a-eng.php. Accessed May 1, 2014. 17. Health Canada. Health Canada is taking action to have small, powerful magnet sets removed from the marketplace. Health Canada Advisory. 2013 May 22;RA-31619. Available at: http://www.healthycanadians.gc. ca/recall-alert-rappel-avis/hc-sc/2013/31619a-eng.php. Accessed May 1, 2014. 18. Health Canada. Level 2 Risk Assessment. Case # 2012–005721. Date Approved: 2013-03-08. 19. Hussain SZ, Bousvaros A, Gilger M, Mamula P, Gupta S, Kramer R, et al. Management of ingested magnets in children. J Pediatr Gastroenterol Nutr 2012;55:239-42.
Strickland, Rosenfield, and Fecteau
Study design In this retrospective chart review, we searched our institution’s electronic patient record for patients less than 18 years old who were diagnosed with magnetic foreign body ingestion between 2002 and 2012. Cases were analyzed for patient, magnetic foreign body, and management characteristics. Incidence rates and case characteristics were compared between the first 8 years of the study period and the last 3. Results We identified 94 patients who met our search criteria. Of confirmed ingestions, the median age was 4.5 years and 65% were male. The incidence of visits increased between the 2002-2009 period and the 20102012 period by a factor of 2.94 (95% CI, 1.84-4.70), whereas the incidence of injuries involving multiple magnets increased by a factor of 8.40 (95% CI, 3.44-20.56). The volume of the magnets decreased from 878.6 mm3 to 259.8 mm3. Six cases required surgical removal of the magnets because of intra-abdominal sepsis or concern for imminent bowel perforation. Conclusions Since 2002, there has been a significant increase in the incidence of magnetic foreign body injuries. These injuries have increasingly involved multiple, smaller magnets and required operative intervention. (J Pediatr 2014;-:---).
P
ediatric magnet ingestions have received increasing attention over the past 10 years. Although most smooth, ingested foreign bodies pass innocuously through the gastrointestinal tract,1 multiple magnets pose the unique danger of being able to attract each other through different loops of bowel, arresting their movement, and potentially causing mural pressure necrosis. This can lead to bowel perforation, fistula formation, volvulus, obstruction, intra-abdominal sepsis, and death.1-6 With the advent of stronger neodymium-iron-boron magnets and their inclusion as part of children’s toys, jewelry, and desk toys, there has been a documented increase7-9 in the number of cases resulting in serious morbidity6 and in rare cases, mortality.4,5 Injury surveillance data from the US,4 Canada,10 and Australia11 suggested as early as 2006 that this was a developing trend. More recently, 2 groups7,8 examined data from the US National Electronic Injury Surveillance System and showed that the rate of magnet-related injury had increased dramatically over the period from 2002 to 2011. One large, urban pediatric hospital in the US has published its experience and demonstrated an apparent increase in the number of ingestions and an increasing proportion involving multiple magnets.12 The purpose of our study was to examine the epidemiology and temporal trends of magnet-related injury at a large, Canadian pediatric hospital. Where possible, we aimed to examine the type and number of magnets involved to seek evidence on how shifting magnet technology was involved in this evolving injury pattern. We hypothesized that there would have been a significant increase in magnet-related injury from 2002-2012, with a detectable shift toward smaller magnets and ingestions involving multiple magnets. With this, we expected to find an increase in the morbidity associated with these ingestions.
Methods We performed a retrospective study of all emergency department (ED) visits between April 1, 2002 and December 31, 2012, to a single urban tertiary care pediatric ED with an average annual volume of approximately 55 000 visits over the study period. This included patients referred by community physicians directly to our gastrointestinal, otolaryngology, and general surgery services via the ED. (In these cases, the patients are not assessed by the emergency staff, but are held in the ED until assessed by the consultant services.) Our hospital serves as 1 of 4 acute-care pediatric hospitals in Ontario, Canada, a province of 13.5 million people. It acts as a referral center for all pediatric subspecialties as well as being the local hospital for children living in the surrounding urban neighborhoods. We identified cases by searching through all ED visits with International Classification of Diseases, 10th revision (ICD-10) codes corresponding to foreign From the Hospital for Sick Children, Division of General 1
2
Surgery, and 3Department of Pediatrics. University of Toronto, Toronto, Ontario, Canada
ED ICD-10 IRR
Emergency department International Classification of Diseases,10th revision Incidence rate ratio
The authors declare no conflicts of interest. 0022-3476/$ - see front matter. Copyright ª 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jpeds.2014.04.002
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bodies in the alimentary tract (T18.x). In the province of Ontario, all hospital diagnoses and procedures are labeled and collected using ICD-10 codes for administrative purposes. We also reviewed the administrative database of consultations performed by the general surgery service to assure no cases were missed. All charts were reviewed by authors M.S. or D.R. to identify patients who met the inclusion criteria. This criteria included all patients under 18 years of age suspected of or confirmed to have a magnet ingestion via parental report, diagnostic imaging, or pathology report. Children presenting on multiple occasions with respect to the same ingestion event were abstracted as a single case. We did not include patients who were seen with a foreign body in the external eye, ear, respiratory tract, or genitourinary tract. We chose to limit our scope to the alimentary tract because the majority of complications reported with magnet ingestions arise from perforations and fistulae of the stomach, small bowel, and colon.6 We collected data on patient demographics; type of imaging obtained and findings; patient disposition; procedures or operations; length of hospital stay; and specialist consults. For all encounters where diagnostic imaging was available, 2 observers independently examined the films to assess for number, shape, and approximate size (using the linear measurement tool of our digital image viewing software [GE Centricity RA1000 Workstation v 3.2; GE, Little Chalfont, United Kingdom]) of
Table I. Summary of patient demographics, care received, and magnet characteristics Alimentary tract magnet ED presentations Confirmed magnets (%)* Ingestions Anal insertions Suspected magnet ingestion (%)† Multiple magnets (% of confirmed ingestion) Magnets with other metallic FB (% of confirmed ingestion) Sex (% of confirmed ingestion) M Female Age in years, median Minimum Maximum Developmental disabilities (% of confirmed ingestion) Autism Global developmental delay Diagnostic tests (%) Imaging Blood work Procedures (% of confirmed ingestion) Esophagogastroduodenoscopy Colonoscopy Rigid sigmoidoscopy Rigid esophagoscopy Surgical removal Shape of magnet assessed (% of confirmed ingestion) Spherical Cylindrical Other
94 75 (80) 72 3 19 (20) 30 (42) 2 (3) 47 (65) 25 (35) 4.6 1.1 13.1 4 (5) 3 (4) 1 (1)
the magnets. Magnet volume was calculated for foreign bodies where orthogonal views allowed both observers to confidently assess the shape and obtain necessary measurements to calculate the approximate volume. To examine whether a difference in magnet-injury epidemiology might be attributable to the widespread introduction of small spherical magnet sets in 2009,13,14 we compared the first 8 years (2002-2009, period 1) of the study period to the last 3 years (2010-2012, period 2). We used our institution’s annually reported number of ED visits to create magnet-related injury rates. We used Poisson regression as well as 2-tailed t tests with unequal variance to compare incidence rates and magnet characteristics between these 2 time periods. The study was approved by the hospital’s Research Ethics Board.
Results Between April 1, 2002 and December 31, 2012, a total of 2722 patient visits were classified as injury because of alimentary tract foreign bodies. Upon reviewing these files, 94 unique children were identified as meeting our inclusion criteria. In 75, magnets were confirmed after removal or by a combination of history of magnet ingestion and at least one radioopaque foreign body seen on medical imaging. The remaining 19 patients presented because of suspicion of ingestion, but either no magnets were found on imaging or no further workup was conducted. Demographic data are summarized in Table I. The incidence rate ratio (IRR) of magnet-related injuries after the introduction of the desk toys was 2.94 (95% CI, 1.84-4.70). The IRR for magnet-related injuries with multiple magnets was 8.4 (95% CI, 3.44-20.56). The year-to-year IRR over the entire study period was 1.08 (95% CI, 0.61-1.55) for magnet-related injuries and 2.13 (95% CI, 1.23-3.02) for cases involving multiple magnets. Incidence over time is illustrated in the Figure.
72 (100) 11 (15) 7 (10) 1 (1) 1 (1) 1 (1) 6 (8) 66 (88) 30 (46) 28 (42) 8 (12)
M, male. *Either confirmed at time of removal or by a history of suspected or witnessed magnet ingestion and presence of radio-opaque FB on imaging. †Presented with history of magnet ingestion but no workup was conducted or imaging failed to confirm presence of radio-opaque FB.
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Figure. Incidence (per 100 000 ED visits) of alimentary tract magnet injuries over time. Strickland, Rosenfield, and Fecteau
- 2014
ORIGINAL ARTICLES
The median approximated volume of individual magnets, as determined from dimensions obtained on radiography, went from 878.6 mm3 in period 1 to 259.8 mm3 in period 2 (P = .04). Median age of patients at presentation did not increase significantly over the course of the study period (4.5 vs 4.7, P = .3). Six surgical interventions (Table II) were performed for intra-abdominal sepsis (defined by clinical criteria, including tachycardia, pyrexia, and/or worsening peritonitis) secondary to gastrointestinal perforation. All 6 of these cases occurred in the last 2 years of our study period (2011-2012) and are summarized in Table II. Furthermore, there were 10 endoscopic removals of magnets, all in 2010 and later.
Discussion This single institutional series identifies a significant increase in the incidence rate of multiple magnet-related injuries between 2002 and 2012. More concerning than the simple rise in incidence, however, is the increased number of high-risk injuries featuring multiple, smaller magnets. These changes are in keeping with the documented technological shift from ferrite magnets to neodymium-iron-boron magnets that are approximately 10-20 times more powerful and often sold as sets of 125 or 216 spheres approximately 5 mm in diameter or as part of toy construction kits. The increase in injuries that we report has developed despite new magnetspecific toy standards, labeling requirements, product recalls, and safety advisories4,15,16 all issued in the past 10 years as dangers were identified.
Our data demonstrate a further important trend in the morbidity of magnets in the alimentary tract. All 16 cases requiring operative or endoscopic intervention occurred during the last 3 years of the study period. It is worth reporting that of the children requiring surgical intervention, all 6 were males. This finding is different from other case series in the literature, where the sex demographics of those requiring operations reflect that of the overall ingesting population. Although we did not have any deaths in this series, a number of our patients did require laparotomies and some required small bowel resections for intra-abdominal sepsis. Shortly after the end of our study period, Health Canada, the national department responsible for public health, issued a recall of neodymium-iron-boron magnet sets marketed as desk toys.17 This was escalated to the country’s first-ever mandatory product recall after one manufacturer failed to comply.14 Although curbing future supply will likely have a protective effect against further magnet-related injuries, there are hundreds of thousands of magnet sets already in the homes of Canadian consumers and these pose an ongoing threat to children.18 Magnets for refrigerators, jewelry, and other uses are not covered as part of the recall and online sales of similar toys are difficult to police. Therefore, in the near future, education for physicians and parents on the health dangers of magnets will be an important pillar in the prevention of further injuries. Recently published algorithms outline how primary care physicians and specialists can work together collaboratively to manage these patients.19 Our study had limitations. It was a retrospective chart review based on ICD-coded ED visits and an administrative
Table II. Summary of cases managed surgically Year
Age
Sex
No. of magnets
LOS (days)
Operation
2011
3 y 10 m
M
5
2
2011
3 y 2 mo
M
3
4
2011
3 y 4 mo
M
17
8
2012
12 y 1 mo
M
3
8
Laparoscopy with exteriorization of appendix, enterotomy via appendix, removal of magnets from caecum, appendectomy. Laparoscopy with exteriorization of small bowel, enterotomy, removal of magnets, and repair of small bowel fistula. Laparoscopy converted to laparotomy with enterotomy and gastrotomy for removal of magnets, small bowel resection (3.0 cm), side-to-side stapled anastomosis, and primary repair of perforations. Laparoscopy, converted to laparotomy with enterotomy, removal of FB from small bowel, and primary repair.
2012
3 y 0 mo
M
4
8
2012
3 y 3 mo
M
3
4
Laparoscopy with exteriorization of small bowel, enterotomy, removal of magnets, and primary repair of 8 perforations. Laparoscopy with exteriorization of small bowel, enterotomy, extraction of magnets, resection of small bowel (4.5 cm), and end-to-end anastomosis.
Complications None.
None.
Ileus. Postoperative fever. Returned with superficial surgical site infection.
Returned within 6 mo with small bowel obstruction. Laparotomy with, lysis of adhesions. Postoperative fever.
None.
LOS, length of stay.
Magnetic Foreign Body Injuries: A Large Pediatric Hospital Experience
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database and, as such, cases may have been missed due to improper coding. As a tertiary referral center for pediatric subspecialty care, patients are referred from across the province with high care requirements. Our rates of magnetrelated injuries requiring procedures for removal are thus likely exaggerated compared with the province-wide incidence among pediatric ED visits. Even before the recent federal government action against magnets, several lower-profile warnings, news stories, and toy recalls had elevated public awareness of the dangers of magnet ingestion. This may have driven more parents to seek medical care for alimentary tract magnets in the latter part of our study period. Increasing awareness amongst physicians may also have decreased the threshold to perform endoscopy for magnet retrieval, inflating the number of interventions in the latter part of our study period. In addition, early in the study, many of the balls in children’s ball-and-rod construction sets were not actually magnetic, relying on magnets in the rods instead. Some of the confirmed, radio-opaque ingested spheres reported by parents as magnetic may have simply been the inert ball component of these sets. Our institutional experience from 2002-2012 demonstrates a recent rise in alimentary tract magnets and incidence of multiple magnet ingestion. We further showed a statistically significant decrease in the size of implicated magnets and a trend toward greater morbidity. This data spans a greater than 10-year period before the Canadian government placed heavy restrictions on the sale of small, powerful magnet sets. Given the existing number of magnet sets as well as other, uncontrolled sources of magnets already in homes and schools, education of parents, teachers, and primary care physicians will be important to prevent further harm. n Submitted for publication Nov 13, 2013; last revision received Feb 6, 2014; accepted Apr 2, 2014. Reprint requests: Matt Strickland, MD, BASc, Division of General Surgery, c/o The Hospital for Sick Children, 555 University Ave, Rm 1526, Toronto, Ontario, Canada M5G 1X8. E-mail: [email protected]
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Strickland, Rosenfield, and Fecteau
