525922
research-article2014
AORXXX10.1177/0003489414525922Annals of Otology, Rhinology & LaryngologyKeereweer et al
Article
Case Report: Traumatic Displacement of a Cochlear Implant Magnet
Annals of Otology, Rhinology & Laryngology 2014, Vol. 123(4) 229–231 © The Author(s) 2014 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/0003489414525922 aor.sagepub.com
Stijn Keereweer, MD1, Marc P. Van der Schroeff, MD, PhD1, and Bas Pullens, MD1
Abstract Objectives: To date, over 200 000 cochlear implants (CIs) have been implanted worldwide and the incidence is still increasing. We present a case of traumatic displacement of CI magnet to raise awareness about this complication and to highlight the need for vigilance during surgery as well as for proper counseling. Methods: The clinical presentation of a 1.5-year-old boy with a traumatic displacement of a CI magnet was presented and the literature was reviewed for this rare complication. Results: After minor head injury, the sound processor could no longer connect to the CI. X-ray imaging demonstrated displacement of the CI magnet. During revision surgery, the magnet was replaced by a new magnet in the silicon holding cap. Intraoperative impedance measurements were normal and the CI was successfully activated 4 weeks postoperatively. Conclusions: Clinicians and patients should be aware of the risk of displacement of the CI magnet after (minor) head injury. Young boys tend to have a higher risk for this complication. Keywords cochlear implant, traumatic displacement
Case Presentation A 1.5-year-old congenitally deaf boy had received a cochlear implant (CI), Cochlear Nucleus, in his right ear at 1 year of age according to standard procedures. This included drilling of a bony well for the magnet and placement of the CI using the tight-pocket technique, but tiedown sutures or rigid fixation were not used. Six months after the operation, the boy fell from the stairs resulting in minor head trauma, while wearing the sound processor. After this incident, the sound processor could no longer connect to the CI. Diffuse swelling without erythema was seen of the skin overlying the CI. X-ray imaging revealed displacement of the CI magnet that was no longer in its holding pocket but now placed directly on top of the titanium housing of the receiver-stimulator (Figure 1). During revision surgery, the magnet was replaced by a new magnet in the silicon holding cap (Figure 2). The silicon ring had only minor damage and the electrodes were not dislocated. Intraoperative impedance measurements were normal and the CI was successfully activated 4 weeks postoperatively.
Discussion To date, over 200 000 CIs have been implanted worldwide, and the incidence is still increasing. Magnet displacement
after magnetic resonance imaging is a rare but well-known complication that can occur even in compatible devices despite adequate precautionary measurements.1 Traumatic displacement of the CI magnet is even more uncommon, and is described in less than 0.5% of young children with a CI.2 Young boys have a greater risk of head trauma due to poorer motor control and explorative behavior.3 This complication was first described by Yun et al,3 who postulated that the risk of traumatic displacement of the magnet could be higher in small children due to a thinner scalp overlying the CI. Furthermore, they suggested that the higher curvature of the skull resulting from a relatively small head circumference could place the magnet at a greater angle relative to the stimulator-receiver.3 These features could also have played a role in our case of a young boy, resulting in dislocation of the magnet caused by wearing of the sound processor during trauma.
1
Department of Otorhinolaryngology, Sophia Children’s Hospital, Erasmus Medical Centre, Rotterdam, the Netherlands Corresponding Author: Stijn Keereweer, MD, Department of Otorhinolaryngology, Sophia Children’s Hospital, Erasmus Medical Centre, ‘s-Gravendijkwal 230, Rotterdam, 3015 CE, the Netherlands. Email: [email protected]
Downloaded from aor.sagepub.com at NORTH CAROLINA STATE UNIV on March 30, 2015
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Annals of Otology, Rhinology & Laryngology 123(4)
Figure 1. X-ray imaging showing displacement of the cochlear implant magnet. (A) Lateral view demonstrating the empty silicon holding cap (upper black arrow) and the magnet on top of the receiver-stimulator titanium housing (lower black arrow). (B) Frontal view. The empty silicon holding cap (upper white arrow) and the magnet on top of the receiver-stimulator titanium housing (lower white arrow) are shown.
Figure 2. Intraoperative findings and replacement of the cochlear implant (CI) magnet. (A) Diffuse swelling of the skin overlying the CI. (B) After formation of the skin flap, the CI magnet was found on top of the titanium housing. (C) The magnet was removed from the housing, and the empty silicon holding pocket is shown. (D) A new magnet was placed in the holding cap.
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Keereweer et al Declaration of Conflicting Interests
References
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
1. Deneuve S, Loundon N, Leboulanger N, et al. Cochlear implant magnet displacement during magnetic resonance imaging. Otol Neurotol. 2008;29:789-190. 2. Loundon N, Blanchard M, Roger G, et al. Medical and surgical complications in pediatric cochlear implantation. Arch Otolaryngol Head Neck Surg. 2010;136:12-15. 3. Yun JM, Colburn MW, Antonelli PJ. Cochlear implant magnet displacement with minor head trauma. Otolaryngol Head Neck Surg. 2005;133:275-277.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
Downloaded from aor.sagepub.com at NORTH CAROLINA STATE UNIV on March 30, 2015
research-article2014
AORXXX10.1177/0003489414525922Annals of Otology, Rhinology & LaryngologyKeereweer et al
Article
Case Report: Traumatic Displacement of a Cochlear Implant Magnet
Annals of Otology, Rhinology & Laryngology 2014, Vol. 123(4) 229–231 © The Author(s) 2014 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/0003489414525922 aor.sagepub.com
Stijn Keereweer, MD1, Marc P. Van der Schroeff, MD, PhD1, and Bas Pullens, MD1
Abstract Objectives: To date, over 200 000 cochlear implants (CIs) have been implanted worldwide and the incidence is still increasing. We present a case of traumatic displacement of CI magnet to raise awareness about this complication and to highlight the need for vigilance during surgery as well as for proper counseling. Methods: The clinical presentation of a 1.5-year-old boy with a traumatic displacement of a CI magnet was presented and the literature was reviewed for this rare complication. Results: After minor head injury, the sound processor could no longer connect to the CI. X-ray imaging demonstrated displacement of the CI magnet. During revision surgery, the magnet was replaced by a new magnet in the silicon holding cap. Intraoperative impedance measurements were normal and the CI was successfully activated 4 weeks postoperatively. Conclusions: Clinicians and patients should be aware of the risk of displacement of the CI magnet after (minor) head injury. Young boys tend to have a higher risk for this complication. Keywords cochlear implant, traumatic displacement
Case Presentation A 1.5-year-old congenitally deaf boy had received a cochlear implant (CI), Cochlear Nucleus, in his right ear at 1 year of age according to standard procedures. This included drilling of a bony well for the magnet and placement of the CI using the tight-pocket technique, but tiedown sutures or rigid fixation were not used. Six months after the operation, the boy fell from the stairs resulting in minor head trauma, while wearing the sound processor. After this incident, the sound processor could no longer connect to the CI. Diffuse swelling without erythema was seen of the skin overlying the CI. X-ray imaging revealed displacement of the CI magnet that was no longer in its holding pocket but now placed directly on top of the titanium housing of the receiver-stimulator (Figure 1). During revision surgery, the magnet was replaced by a new magnet in the silicon holding cap (Figure 2). The silicon ring had only minor damage and the electrodes were not dislocated. Intraoperative impedance measurements were normal and the CI was successfully activated 4 weeks postoperatively.
Discussion To date, over 200 000 CIs have been implanted worldwide, and the incidence is still increasing. Magnet displacement
after magnetic resonance imaging is a rare but well-known complication that can occur even in compatible devices despite adequate precautionary measurements.1 Traumatic displacement of the CI magnet is even more uncommon, and is described in less than 0.5% of young children with a CI.2 Young boys have a greater risk of head trauma due to poorer motor control and explorative behavior.3 This complication was first described by Yun et al,3 who postulated that the risk of traumatic displacement of the magnet could be higher in small children due to a thinner scalp overlying the CI. Furthermore, they suggested that the higher curvature of the skull resulting from a relatively small head circumference could place the magnet at a greater angle relative to the stimulator-receiver.3 These features could also have played a role in our case of a young boy, resulting in dislocation of the magnet caused by wearing of the sound processor during trauma.
1
Department of Otorhinolaryngology, Sophia Children’s Hospital, Erasmus Medical Centre, Rotterdam, the Netherlands Corresponding Author: Stijn Keereweer, MD, Department of Otorhinolaryngology, Sophia Children’s Hospital, Erasmus Medical Centre, ‘s-Gravendijkwal 230, Rotterdam, 3015 CE, the Netherlands. Email: [email protected]
Downloaded from aor.sagepub.com at NORTH CAROLINA STATE UNIV on March 30, 2015
230
Annals of Otology, Rhinology & Laryngology 123(4)
Figure 1. X-ray imaging showing displacement of the cochlear implant magnet. (A) Lateral view demonstrating the empty silicon holding cap (upper black arrow) and the magnet on top of the receiver-stimulator titanium housing (lower black arrow). (B) Frontal view. The empty silicon holding cap (upper white arrow) and the magnet on top of the receiver-stimulator titanium housing (lower white arrow) are shown.
Figure 2. Intraoperative findings and replacement of the cochlear implant (CI) magnet. (A) Diffuse swelling of the skin overlying the CI. (B) After formation of the skin flap, the CI magnet was found on top of the titanium housing. (C) The magnet was removed from the housing, and the empty silicon holding pocket is shown. (D) A new magnet was placed in the holding cap.
Downloaded from aor.sagepub.com at NORTH CAROLINA STATE UNIV on March 30, 2015
231
Keereweer et al Declaration of Conflicting Interests
References
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
1. Deneuve S, Loundon N, Leboulanger N, et al. Cochlear implant magnet displacement during magnetic resonance imaging. Otol Neurotol. 2008;29:789-190. 2. Loundon N, Blanchard M, Roger G, et al. Medical and surgical complications in pediatric cochlear implantation. Arch Otolaryngol Head Neck Surg. 2010;136:12-15. 3. Yun JM, Colburn MW, Antonelli PJ. Cochlear implant magnet displacement with minor head trauma. Otolaryngol Head Neck Surg. 2005;133:275-277.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
Downloaded from aor.sagepub.com at NORTH CAROLINA STATE UNIV on March 30, 2015
