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The effect of radiosurgery on cochlear implant function
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American Journal of Otolaryngology–Head and Neck Medicine and Surgery 32 (2011) 69 – 70 www.elsevier.com/locate/amjoto
Case reports
The effect of radiosurgery on cochlear implant function Soo-Keun Kong, MD, Eui-Kyung Goh, MD⁎, Il-Woo Lee, MD, Kyong-Myong Chon, MD Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine and Medical Research Institute, Pusan National University, Busan, South Korea Received 26 May 2009
Abstract
Cochlear implants are used worldwide for the treatment of severe to profound bilateral sensorineural hearing loss in both adults and children. A number of implantees are likely to be treated with radiosurgery later in life, but very little is known about the effects of radiosurgery on cochlear implants. We report a cochlear-implanted patient who underwent radiosurgery due to a recurrent meningioma. After radiosurgery, the impedance of the implant maintained a normal range, and auditory performance tests were unchanged as compared to before radiosurgery. This is the first report addressing the effects of radiosurgery in a patient with a cochlear implant. © 2011 Elsevier Inc. All rights reserved.
1. Introduction Cochlear implants are used worldwide for the treatment of severe to profound bilateral sensorineural hearing loss in both adults and children. A number of implantees are likely to be treated with radiosurgery later in life, but very little is known about the effects of radiosurgery on cochlear implants. Only 4 studies have focused on the influence of radiation therapy on cochlear implant function in vitro [1-4]. This is the first report addressing the effects of radiosurgery in a patient with a cochlear implant. 2. Case report A 48-year-old woman complained of right total deafness, present since childhood. In 1992, the patient developed left total deafness due to suppurative labyrinthitis, which developed secondary to left chronic otitis media. In 1993, she underwent a left tympanoplasty, and we planned left cochlear implantation. The next year, she underwent left
⁎ Corresponding author. Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine and Medical Research Institute, Pusan National University, 1-10, Ami-dong, Seo-gu, Busan 602-739, South Korea. Tel.: +82 51 240 7332; fax: +82 51 246 8668. E-mail address: [email protected] (E.-K. Goh). 0196-0709/$ – see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.amjoto.2009.08.005
cochlear implantation (CI 22M, Cochlear Ltd, Sydney, Australia) in our clinic. After implantation, the impedances of the electrodes were stable. Auditory performance (SRT 40dB, HINT scores 50/50) was excellent, and the categories of auditory performance scores were 7 [5]. There were no specific problems for ten years. In 2004, the patient complained of sudden dizziness. Computed tomographic brain scans demonstrated a high density, 2.8-cm diameter mass in the right supratent and infratent area (Fig. 1). We suspected a meningioma and transferred the patient to the neurosurgical clinic. Two months later, tumor removal was performed by a neurosurgeon via a right subtemporal craniotomy approach. Histopathological examination disclosed a meningioma. The patient's postoperative course was uneventful. We checked follow-up computed tomographic scans twice a year, and the 2007 follow-up computed tomographic scans revealed a 1.5-cm diameter mass at the same site. We did not check magnetic resonance imaging because the patient refused the demagnetization of implant. We decided to pursue radiosurgery for treatment of this recurrent meningioma because the patient refused surgery. Before pursuing this course of treatment, we explained the risk of implant failure to the patient. She had received a 26-Gy dose of radiosurgery in a single fraction. After radiosurgery, the impedances of the implant were still stable and auditory performance tests (SRT 40dB, HINT scores 50/50, and categories of auditory performance
70
S.-K. Kong et al. / American Journal of Otolaryngology–Head and Neck Medicine and Surgery 32 (2011) 69–70
Fig. 1. Axial computed tomographic scans showing a high-density mass in the right supratent and infratent area.
scores 7) were unchanged as compared to before the procedure. The patient was followed up for 2 years after radiosurgery, and auditory performance remained excellent.
single doses of radiation on the function of the Nucleus 24 k implant (Cochlear Ltd) and concluded that radiosurgery could be performed in patients with the Nucleus 24 k Cochlear implant with a low risk of implant failure at a total dose of up to 42.5 Gy. Klenzner et al [4] also evaluated the influence of conventional and hyperfractional radiotherapy on Nucleus CI24M and CI24R implants (Cochlear Ltd) and suggested that these types of therapy could be used safely with Nucleus CI24M and CI24R implants at doses of 80 Gy or less. Furthermore, the applicability of these results was suggested for clinical practice. The aforementioned studies investigated the effects of radiotherapy on cochlear implants in vitro, but there have been no reports addressing the effects of irradiation in patients with cochlear implants. We reviewed the 4 above studies before pursuing radiosurgery and felt that CI 22M cochlear implants would be able to undergo radiation therapy with a low risk of implant failure at 40 Gy or less. After radiosurgery, we found that the impedance of the implant was still normal and that auditory performance was unchanged as compared to before radiosurgery. We conclude that radiosurgery may have little influence on the risk of cochlear implant failure. Acknowledgment
3. Discussion The number of patients with cochlear implants is growing rapidly. Therefore, cochlear implantation centers should be aware of the potential consequences of radiotherapy in the area of the implant. Very little is known, however, about the specific effects of radiotherapy on cochlear implants. Baumann et al [1] reported that CLARION 1,2 implants (Advanced Bionics, Sylmar, Calif) safely withstood approximately 60 Gy of radiation before experiencing functional difficulties. Ralston et al [2] irradiated CI 22M and CI 24M (Cochlear Ltd) cochlear implants with 4MV photons from a linear accelerator with a single fraction of 2 Gy up to a total dose of 150 Gy. The implants were able to endure radiation therapy with a low risk of unacceptable device damage at 50 Gy or less. Klenzner et al [3] investigated the effects of large
This work was supported for two years by Pusan National University Research Grant. References [1] Baumann R, Lesinski-Schiedat A, Goldring JE, et al. The influence of ionizing radiation on the CLARION 1.2 cochlear implant during radiation therapy. Am J Otol 1999;20:50-2. [2] Ralston A, Stevens G, Mahomudally E, et al. Cochlear implants: response to therapeutic irradiation. Int J Radiat Oncol Biol Phys 1999;44:227-31. [3] Klenzner T, Lutterbach J, Aschendorff A, et al. The effect of large single radiation dose on cochlear implant function: implication for radiosurgery. Eur Arch Otorhinolaryngol 2004;261:251-5. [4] Klenzner T, Knapp F, Rohner F, et al. Influence of ionizing radiation on Nucleus 24 cochlear implants. Otol Neuotol 2005;26:661-7. [5] Archbold S, Lutman ME, Marshall DH. Categories of auditory performance. Ann Otol Rhinol Laryngol Suppl 1995;166:312-4.
American Journal of Otolaryngology–Head and Neck Medicine and Surgery 32 (2011) 69 – 70 www.elsevier.com/locate/amjoto
Case reports
The effect of radiosurgery on cochlear implant function Soo-Keun Kong, MD, Eui-Kyung Goh, MD⁎, Il-Woo Lee, MD, Kyong-Myong Chon, MD Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine and Medical Research Institute, Pusan National University, Busan, South Korea Received 26 May 2009
Abstract
Cochlear implants are used worldwide for the treatment of severe to profound bilateral sensorineural hearing loss in both adults and children. A number of implantees are likely to be treated with radiosurgery later in life, but very little is known about the effects of radiosurgery on cochlear implants. We report a cochlear-implanted patient who underwent radiosurgery due to a recurrent meningioma. After radiosurgery, the impedance of the implant maintained a normal range, and auditory performance tests were unchanged as compared to before radiosurgery. This is the first report addressing the effects of radiosurgery in a patient with a cochlear implant. © 2011 Elsevier Inc. All rights reserved.
1. Introduction Cochlear implants are used worldwide for the treatment of severe to profound bilateral sensorineural hearing loss in both adults and children. A number of implantees are likely to be treated with radiosurgery later in life, but very little is known about the effects of radiosurgery on cochlear implants. Only 4 studies have focused on the influence of radiation therapy on cochlear implant function in vitro [1-4]. This is the first report addressing the effects of radiosurgery in a patient with a cochlear implant. 2. Case report A 48-year-old woman complained of right total deafness, present since childhood. In 1992, the patient developed left total deafness due to suppurative labyrinthitis, which developed secondary to left chronic otitis media. In 1993, she underwent a left tympanoplasty, and we planned left cochlear implantation. The next year, she underwent left
⁎ Corresponding author. Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine and Medical Research Institute, Pusan National University, 1-10, Ami-dong, Seo-gu, Busan 602-739, South Korea. Tel.: +82 51 240 7332; fax: +82 51 246 8668. E-mail address: [email protected] (E.-K. Goh). 0196-0709/$ – see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.amjoto.2009.08.005
cochlear implantation (CI 22M, Cochlear Ltd, Sydney, Australia) in our clinic. After implantation, the impedances of the electrodes were stable. Auditory performance (SRT 40dB, HINT scores 50/50) was excellent, and the categories of auditory performance scores were 7 [5]. There were no specific problems for ten years. In 2004, the patient complained of sudden dizziness. Computed tomographic brain scans demonstrated a high density, 2.8-cm diameter mass in the right supratent and infratent area (Fig. 1). We suspected a meningioma and transferred the patient to the neurosurgical clinic. Two months later, tumor removal was performed by a neurosurgeon via a right subtemporal craniotomy approach. Histopathological examination disclosed a meningioma. The patient's postoperative course was uneventful. We checked follow-up computed tomographic scans twice a year, and the 2007 follow-up computed tomographic scans revealed a 1.5-cm diameter mass at the same site. We did not check magnetic resonance imaging because the patient refused the demagnetization of implant. We decided to pursue radiosurgery for treatment of this recurrent meningioma because the patient refused surgery. Before pursuing this course of treatment, we explained the risk of implant failure to the patient. She had received a 26-Gy dose of radiosurgery in a single fraction. After radiosurgery, the impedances of the implant were still stable and auditory performance tests (SRT 40dB, HINT scores 50/50, and categories of auditory performance
70
S.-K. Kong et al. / American Journal of Otolaryngology–Head and Neck Medicine and Surgery 32 (2011) 69–70
Fig. 1. Axial computed tomographic scans showing a high-density mass in the right supratent and infratent area.
scores 7) were unchanged as compared to before the procedure. The patient was followed up for 2 years after radiosurgery, and auditory performance remained excellent.
single doses of radiation on the function of the Nucleus 24 k implant (Cochlear Ltd) and concluded that radiosurgery could be performed in patients with the Nucleus 24 k Cochlear implant with a low risk of implant failure at a total dose of up to 42.5 Gy. Klenzner et al [4] also evaluated the influence of conventional and hyperfractional radiotherapy on Nucleus CI24M and CI24R implants (Cochlear Ltd) and suggested that these types of therapy could be used safely with Nucleus CI24M and CI24R implants at doses of 80 Gy or less. Furthermore, the applicability of these results was suggested for clinical practice. The aforementioned studies investigated the effects of radiotherapy on cochlear implants in vitro, but there have been no reports addressing the effects of irradiation in patients with cochlear implants. We reviewed the 4 above studies before pursuing radiosurgery and felt that CI 22M cochlear implants would be able to undergo radiation therapy with a low risk of implant failure at 40 Gy or less. After radiosurgery, we found that the impedance of the implant was still normal and that auditory performance was unchanged as compared to before radiosurgery. We conclude that radiosurgery may have little influence on the risk of cochlear implant failure. Acknowledgment
3. Discussion The number of patients with cochlear implants is growing rapidly. Therefore, cochlear implantation centers should be aware of the potential consequences of radiotherapy in the area of the implant. Very little is known, however, about the specific effects of radiotherapy on cochlear implants. Baumann et al [1] reported that CLARION 1,2 implants (Advanced Bionics, Sylmar, Calif) safely withstood approximately 60 Gy of radiation before experiencing functional difficulties. Ralston et al [2] irradiated CI 22M and CI 24M (Cochlear Ltd) cochlear implants with 4MV photons from a linear accelerator with a single fraction of 2 Gy up to a total dose of 150 Gy. The implants were able to endure radiation therapy with a low risk of unacceptable device damage at 50 Gy or less. Klenzner et al [3] investigated the effects of large
This work was supported for two years by Pusan National University Research Grant. References [1] Baumann R, Lesinski-Schiedat A, Goldring JE, et al. The influence of ionizing radiation on the CLARION 1.2 cochlear implant during radiation therapy. Am J Otol 1999;20:50-2. [2] Ralston A, Stevens G, Mahomudally E, et al. Cochlear implants: response to therapeutic irradiation. Int J Radiat Oncol Biol Phys 1999;44:227-31. [3] Klenzner T, Lutterbach J, Aschendorff A, et al. The effect of large single radiation dose on cochlear implant function: implication for radiosurgery. Eur Arch Otorhinolaryngol 2004;261:251-5. [4] Klenzner T, Knapp F, Rohner F, et al. Influence of ionizing radiation on Nucleus 24 cochlear implants. Otol Neuotol 2005;26:661-7. [5] Archbold S, Lutman ME, Marshall DH. Categories of auditory performance. Ann Otol Rhinol Laryngol Suppl 1995;166:312-4.