A New CT-based Categorization of Inner Ear and Internal ... · based categorization that includes...
1
Poster Design & Printing by Genigraphics ® - 800.790.4001 CAP scores (Archbold et al 5 ) 0: no awareness of environmental sounds 4: discriminates at least two speech sounds 1: awareness of environmental sounds 5: understands common phrases without lip-reading 2: responds to speech sounds 6: understands conversation without lip-reading with a familiar talker 3: recognizes environmental sounds 7: can use the telephone with a familiar talker Hiroshi Yamazaki Department of Otolaryngology, Kobe City Medical Center General Hospital, Institute of Biomedical Research and Innovation, Japan Email: [email protected] Phone: +81-78-302-4321 Objective: (1) To reveal the relationship between cochlear implant (CI) outcomes and the types of inner ear and internal auditory canal (IAC) malformation and (2) to establish a high resolution CT (HRCT)-based classification of inner ear and IAC malformations for predicting CI outcomes. Methods: Twenty-four implantees with inner ear and/or IAC malformations were included in this study and they were categorized based on two CT findings: the presence of a bony modiolus in the cochlea and the diameters of the IAC and bony cochlear nerve canal (BCNC). Group 1 (n=11) was defined by both the presence of a bony modiolus and the patency of IAC and BCNC. Group 2 (n=7) showed a cystic cochlea without a bony modiolus. Narrow IAC or hypoplasia of BCNC was observed in Group 3 (n=6). There was no implantee who lacked a bony modiolus as well as showed stenosis of IAC or BCNC in this study. Cochlear implant (CI) outcomes were evaluated in these groups one to three years after implantation. RESULTS: All Group 1 patients showed good CI outcomes and could communicate orally, while all Group 3 patients had poor CI outcomes and required lip-reading or sign language to understand common phrases. The CI outcomes of Group 2 varied between cases, but many showed good CI outcomes. CONCLUSION: Our new CT-based categorization of inner ear and IAC malformations was effective in predicting CI outcomes. A New CT A New CT - - based Categorization of Inner Ear and Internal Auditory Canal Ma based Categorization of Inner Ear and Internal Auditory Canal Ma lformations lformations to Predict Cochlear Implant Outcomes to Predict Cochlear Implant Outcomes Hiroshi Yamazaki 1,3 , Sho Koyasu 2 , Saburo Moroto 1 , Rinko Yamamoto 1 , Tomoko Yamazaki 1 , Keizo Fujiwara 1 , Kyo Itoh 2 , Yasushi Naito 1,3 Between 2004 and 2010, 98 subjects under the age of 20 underwent cochlear implantations in our hospital. We examined inner ear and/or IAC malformations of these patients according to the existing classifications 2, 3, 4 (Table 1). We also categorized our patients with inner ear and/or IAC malformations based on the two criteria: the presence of the bony modiolus and the patency of BCNC and IAC (Figure 2). Onset of profound hearing loss occurred after the age of 5 (post-lingual) in 6 cases and between 2–5 years of age (peri-lingual) in 3 cases. The remaining 15 children were pre-lingually deafened. The mean age at implantation and the mean duration of deafness before implantation was 62.8 months and 27.2 months, respectively. CI outcomes were evaluated by CAP scores 5 and speech discrimination scores. We defined CAP scores of 5–7 as a good CI outcome and scores of 0–4 as a poor one, because a subject with CAP scores of 0–4 cannot understand common phrases without visual language. This study established a new CT-based categorization of both inner ear and IAC malformations. The categorization is simple and is defined by two criteria: the presence or absence of a bony modiolus in the cochlea and the diameters of the IAC and BCNC. We focused on these structures because the bony modiolus contains spiral ganglion cells, the major target of CI-mediated electrical stimulation, and their axons go through the BCNC and the IAC. Our new categorization is effective in predicting CI-aided hearing performance. Our new CT-based categorization based on the presence of a bony modiolus in the cochlea and the diameters of the IAC and BCNC was effective in predicting CI outcomes of children with inner ear and/or IAC malformations. The CI outcomes were the best in Group 1, followed by Group 2 and Group 3. Group 1 cases are good candidates for CI as their CI-aided hearing performance was high and no serious complications were observed. On the other hand, hearing improvement was limited in Group 3, and visual languages were necessary for cases to understand common phrases even after long term CI usage. CI outcomes varied between cases in Group 2, but many could understand common phrases without the need for visual languages. Inner ear and internal auditory canal (IAC) malformations account for approximately 25% of congenital sensorineural hearing loss and an increasing number of children with these malformations are being reported to undergo cochlear implantation. A CT-based classification of inner ear malformations based on the developmental arrest hypothesis was originally proposed by Jackler et al 1 and modified by Sennaroglu et al 2 (Figure 1). This classification of inner ear malformations is essential to investigate the etiology of inner ear malformations, but might not be sufficient for predicting CI outcomes since it does not include IAC malformations such as narrow IAC and hypoplasia of bony cochlear nerve canal (BCNC) which has a negative impact on CI outcomes due to cochlear nerve deficiency 3,4 . The purpose of this study, therefore, was to establish a new, simple CT- based categorization that includes both inner ear and IAC malformations for predicting CI outcomes. INTRODUCTION 1. Jackler RK, et al. Congenital malformations of the inner ear: a classification based on embryogenesis. Laryngoscope 1987:97:2-14. 2. Sennaroglu L. Cochlear implantation in inner ear malformations--a review article. Cochlear Implants Int 2010:11:4-41. 3. Papsin BC. Cochlear implantation in children with anomalous cochleovestibular anatomy. Laryngoscope 2005:115:1-26. 4. Miyasaka M, et al. CT and MR imaging for pediatric cochlear implantation: emphasis on the relationship between the cochlear nerve canal and the cochlear nerve. Pediatr Radiol 2010:40:1509-16. 5. Archbold S, et al. Categories of auditory performance. Ann Otol Rhinol Laryngol Suppl 1995:166:312-4. CONCLUSIONS DISCUSSION METHODS AND MATERIALS REFERENCES ABSTRACT CONTACT Types of inner ear and IAC malformations based on the existing classifications: Of the 98 subjects who underwent implantation prior to the age of 20 at our hospital, CT scans revealed inner ear and/or IAC malformations in 24 (24.5%) at the implanted side (Table 1). A new categorization of inner ear and IAC malformations: In Group 2 (n=7) and Group 3 (n=6), almost all subjects (6 and 5, respectively) were pre-lingually deafened. In Group 1 (n=11), 7 cases were post-lingually or peri-lingually deafened. The mean age at implantation was 75.4 months, 34.9 months, and 72.2 months in Groups 1, 2, and 3, respectively. The mean duration of deafness before implantation was 17.1 months, 30.3 months, and 42.2 months, respectively. MR imaging revealed cochlear nerve deficiency in all cases of Group 3. CI outcomes: The postoperative CAP score was 5 in all cases of Group 1 and reached 7, the maximum score, in 7 of 11 cases. However, the postoperative CAP score did not exceed 4 in all cases of Group 3. In Group 2, the postoperative CAP score remained 4 in 2 even after three years of CI usage, but reached 5 or 6 in the remaining 5 cases. Thus, all of Group 1 and 5 cases of Group 2 achieved good CI outcomes, while the remaining 8 cases including all of Group 3 showed poor CI outcomes (Figure 2). As shown in Figure 2, our new categorization enabled us to better discriminate between good and poor outcomes compared with existing categorization methods. The correct percentage of the closed-set infant word discrimination test was 80 in all cases of Group 1, while the score ranged from 40–60 in tested cases of Group 3. In Group 2, the correct percentage varied widely between cases, ranging from 55–100. RESULTS CC CC IP‐I IP‐I IP‐II IP‐II large vestibular aqueduct syndrome LVAS LVAS cochlear hypoplasia Labyrinth aplasia IP‐III IP‐III CH‐I, ‐II, ‐III CH‐I, ‐II, ‐III (Sennaroglu L. 2002, 2010) CH CH CC IP-I (CH-II ) CH-I IP-III absent CH-III IP-II LVAS present normal Patency of the IAC and BCNC (Miyasaka M, 2010) Narrow IAC <2mm Hypoplasia of BCNC <1.5mm NIAC NIAC HBCNC HBCNC coronal axial (Papsin BC, 2005) Presence of a bony modiolus Two criteria for our categorization Figure 1: Classification of Inner Ear Malformations Table 1: Imaging Findings in the 24 Implated Ears Figure 2: Two Criteria for Our Categorization Including both Inner Ear and IAC malformations * * The existing classifications Our new categorization Figure 2: Postoperative CAP Scores of 24 Patients Table 2. CI Outcomes of the Groups in Our New Categorization This caes with CH-III and HBCNC is plotted twice(*)
Transcript of A New CT-based Categorization of Inner Ear and Internal ... · based categorization that includes...
Poster Design & Printing by Genigraphics® - 800.790.4001
CAP scores (Archbold et al5)0: no awareness of environmental sounds 4: discriminates at least two speech sounds1: awareness of environmental sounds 5: understands common phrases without lip-reading2: responds to speech sounds 6: understands conversation without lip-reading with a familiar talker3: recognizes environmental sounds 7: can use the telephone with a familiar talker
Hiroshi YamazakiDepartment of Otolaryngology, Kobe City Medical Center General Hospital, Institute of Biomedical Research and Innovation, JapanEmail: [email protected]: +81-78-302-4321
Objective: (1) To reveal the relationship between cochlear implant (CI) outcomes and the types of inner ear and internal auditory canal (IAC) malformation and (2) to establish a high resolution CT (HRCT)-based classification of inner ear and IAC malformations for predicting CI outcomes.Methods: Twenty-four implantees with inner ear and/or IAC malformations were included in this study and they were categorized based on two CT findings: the presence of a bony modiolus in the cochlea and the diameters of the IAC and bony cochlear nerve canal (BCNC). Group 1 (n=11) was defined by both the presence of a bony modiolus and the patency of IAC and BCNC. Group 2 (n=7) showed a cystic cochlea without a bony modiolus. Narrow IAC or hypoplasia of BCNC was observed in Group 3 (n=6). There was no implantee who lacked a bony modiolus as well as showed stenosis of IAC or BCNC in this study. Cochlear implant (CI) outcomes were evaluated in these groups one to three years after implantation.RESULTS: All Group 1 patients showed good CI outcomes and could communicate orally, while all Group 3 patients had poor CI outcomes and required lip-reading or sign language to understand common phrases. The CI outcomes of Group 2 varied between cases, but many showed good CI outcomes.CONCLUSION: Our new CT-based categorization of inner ear and IAC malformations was effective in predicting CI outcomes.
A New CTA New CT--based Categorization of Inner Ear and Internal Auditory Canal Mabased Categorization of Inner Ear and Internal Auditory Canal Malformationslformationsto Predict Cochlear Implant Outcomesto Predict Cochlear Implant Outcomes
Hiroshi Yamazaki1,3, Sho Koyasu2, Saburo Moroto1, Rinko Yamamoto1, Tomoko Yamazaki1, Keizo Fujiwara1, Kyo Itoh2, Yasushi Naito1,3
Between 2004 and 2010, 98 subjects under the age of 20 underwentcochlear implantations in our hospital. We examined inner ear and/or IAC malformations of these patients according to the existing classifications2,
3, 4 (Table 1). We also categorized our patients with inner ear and/or IAC malformations based on the two criteria: the presence of the bony modiolus and the patency of BCNC and IAC (Figure 2).
Onset of profound hearing loss occurred after the age of 5 (post-lingual) in 6 cases and between 2–5 years of age (peri-lingual) in 3 cases. The remaining 15 children were pre-lingually deafened. The mean age at implantation and the mean duration of deafness before implantation was 62.8 months and 27.2 months, respectively. CI outcomes were evaluated by CAP scores5 and speech discrimination scores. We defined CAP scores of 5–7 as a good CI outcome and scores of 0–4 as a poor one, because a subject with CAP scores of 0–4 cannot understand common phrases without visual language.
This study established a new CT-based categorization of both inner ear and IAC malformations. The categorization is simple and is defined by two criteria: the presence or absence of a bony modiolus in the cochlea and the diameters of the IAC and BCNC. We focused on these structures because the bony modiolus contains spiral ganglion cells, the major target of CI-mediated electrical stimulation, and their axons go through the BCNC and the IAC. Our new categorization is effective in predicting CI-aided hearing performance.
Our new CT-based categorization based on the presence of a bony modiolus in the cochlea and the diameters of the IAC and BCNC was effective in predicting CI outcomes of children with inner ear and/or IAC malformations. The CI outcomes were the best in Group 1, followed by Group 2 and Group 3. Group 1 cases are good candidates for CI as their CI-aided hearing performance was high and no serious complications were observed. On the other hand, hearing improvement was limited in Group 3, and visual languages were necessary for cases to understand common phrases even after long term CI usage. CI outcomes varied between cases in Group 2, but many could understand common phrases without the need for visual languages.
Inner ear and internal auditory canal (IAC) malformations account for approximately 25% of congenital sensorineural hearing loss and an increasing number of children with these malformations are beingreported to undergo cochlear implantation.
A CT-based classification of inner ear malformations based on the developmental arrest hypothesis was originally proposed by Jackler et al1and modified by Sennaroglu et al2 (Figure 1). This classification of inner ear malformations is essential to investigate the etiology of inner ear malformations, but might not be sufficient for predicting CI outcomes since it does not include IAC malformations such as narrow IAC and hypoplasia of bony cochlear nerve canal (BCNC) which has a negative impact on CI outcomes due to cochlear nerve deficiency3,4.
The purpose of this study, therefore, was to establish a new, simple CT-based categorization that includes both inner ear and IAC malformations for predicting CI outcomes.
INTRODUCTION
1. Jackler RK, et al. Congenital malformations of the inner ear: a classification based on embryogenesis. Laryngoscope 1987:97:2-14.
2. Sennaroglu L. Cochlear implantation in inner ear malformations--a review article. Cochlear Implants Int 2010:11:4-41.
3. Papsin BC. Cochlear implantation in children with anomalous cochleovestibular anatomy. Laryngoscope 2005:115:1-26.
4. Miyasaka M, et al. CT and MR imaging for pediatric cochlear implantation: emphasis on the relationship between the cochlear nerve canal and the cochlear nerve. Pediatr Radiol 2010:40:1509-16.
5. Archbold S, et al. Categories of auditory performance. Ann Otol Rhinol Laryngol Suppl 1995:166:312-4.
CONCLUSIONS
DISCUSSION
METHODS AND MATERIALS
REFERENCES
ABSTRACT
CONTACT
Types of inner ear and IAC malformations based on the existing classifications: Of the 98 subjects who underwent implantation prior to the ageof 20 at our hospital, CT scans revealed inner ear and/or IAC malformations in 24 (24.5%) at the implanted side (Table 1).
A new categorization of inner ear and IAC malformations: In Group 2 (n=7) and Group 3 (n=6), almost all subjects (6 and 5, respectively) were pre-lingually deafened. In Group 1 (n=11), 7 cases were post-lingually or peri-lingually deafened. The mean age at implantation was 75.4 months, 34.9 months, and 72.2 months in Groups 1, 2, and 3, respectively. The mean duration of deafness before implantation was 17.1 months, 30.3 months, and 42.2 months, respectively. MR imaging revealed cochlear nerve deficiency in all cases of Group 3.
CI outcomes: The postoperative CAP score was 5 in all cases of Group 1 and reached 7, the maximum score, in 7 of 11 cases. However, thepostoperative CAP score did not exceed 4 in all cases of Group 3. In Group 2, the postoperative CAP score remained 4 in 2 even after three years of CI usage, but reached 5 or 6 in the remaining 5 cases. Thus, all of Group 1 and 5 cases of Group 2 achieved good CI outcomes, while the remaining 8 cases including all of Group 3 showed poor CI outcomes (Figure 2). As shown in Figure 2, our new categorization enabled us to better discriminate between good and poor outcomes compared with existing categorization methods. The correct percentage of the closed-set infant word discrimination test was 80 in all cases of Group 1, while the score ranged from 40–60 in tested cases of Group 3. In Group 2, the correct percentage varied widely between cases, ranging from 55–100.
RESULTS
CCCC
IP‐IIP‐I
IP‐IIIP‐II
large vestibularaqueduct syndrome
LVASLVAS
cochlearhypoplasia
Labyrinth aplasia
IP‐IIIIP‐III
CH‐I, ‐II, ‐IIICH‐I, ‐II, ‐III
(Sennaroglu L. 2002, 2010)
CHCH
CC IP-I
(CH-II )
CH-IIP-III
abse
nt
CH-IIIIP-II LVAS
pres
ent
normal
Patency of the IAC and BCNCPatency of the IAC and BCNC
(Miyasaka M, 2010)
Narrow IAC
<2mm
Hypoplasia of BCNC
<1.5mm
NIACNIAC HBCNCHBCNC
coronal axial
(Papsin BC, 2005)
Presence of a bony modiolusPresence of a bony modiolusTwo criteria for our categorizationTwo criteria for our categorization
Figure 1: Classification of Inner Ear Malformations
Table 1: Imaging Findings in the 24 Implated Ears
Figure 2: Two Criteria for Our Categorization Including both Inner Ear and IAC malformations
* *
The existing classifications Our new categorization
Figure 2: Postoperative CAP Scores of 24 Patients
Table 2. CI Outcomes of the Groups in Our New Categorization
This caes with CH-IIIand HBCNC is plotted twice(*)
