AM ER IC AN JOUR NA L OF OTOLARY NG OLOG Y –H EA D A N D N E CK ME D I CI N E AN D SUR G E RY 3 5 ( 2 0 14 ) 25 7–2 6 0
Available online at www.sciencedirect.com
ScienceDirect www.elsevier.com/locate/amjoto
Cochlear implantation after resection of an intralabyrinthine schwannoma☆,☆☆,★ Christopher A. Schutt, MD⁎, John F. Kveton, MD Yale Department of Surgery, Section of Otolaryngology, New Haven, CT, USA
ARTI CLE I NFO
A BS TRACT
Article history:
Intralabyrinthine schwannomas are rare tumors of the distal ends of the cochlear and
Received 18 October 2013
vestibular nerve. Their presence can be debilitating secondary to symptoms of hearing loss, vertigo, tinnitus, and imbalance. Currently, treatment to restore hearing in those who have become profoundly deaf is not attempted. Additionally, resection in patients with functioning hearing is rare, as the surgery assures deafness. We report the first case demonstrating the feasibility of resection of an intralabyrinthine schwannoma with immediate cochlear implantation. This technique addresses the patients hearing status by taking into account advancing technology, allowing for an improved quality of life. © 2014 Elsevier Inc. All rights reserved.
1.
Introduction
Intralabyrinthine schwannomas are a type of rare tumor that represents a distinct clinical entity, separate from vestibular schwannomas [1–3]. Common complaints include hearing loss, vertigo, tinnitus, imbalance and aural fullness [1,2]. Because symptoms mimic many neurotologic pathologies, especially Meniere's disease, there is often a delay to diagnosis. Fluctuating hearing is found in only 3% of tumors helping in differentiation [2,4]. The diagnosis of an intralabyrinthine schwannoma is made by MRI, showing enhancement in T1 post-gadolinium images [4]. T2 images may further delineate the extent of the mass through loss of fluid signal, caused by the presence of tumor [5]. Surgical removal has previously been reserved for patients with debilitating vertigo in a non-hearing ear, in those rare cases of tumor growth and when concern about pathologic diagnosis exists, since the invasive nature of the surgery assures deafness [3]. These
treatments have not taken into account advancing technologies such as cochlear implants. Our case demonstrates the value of surgical treatment in effort to decrease vertigo and tinnitus while restoring hearing though the resection of tumor with immediate cochlear implantation.
2.
Case report
A 65-year-old male was seen in consultation for severe vertigo with imbalance associated with moderate to severe left fluctuating hearing loss and aural fullness for 3 months. The patient experienced progressive right profound hearing loss over the prior 12 years. Tinnitus occurred in both ears but was more prominent on the right side. Vestibular-evoked myopotentials were absent bilaterally indicating a peripheral pathology, but caloric examination was normal. A diagnosis of bilateral Meniere's disease was made and treatment with a
☆
Funding source: None. Conflicts of interest: None. ★ Research support: None. ⁎ Corresponding author. Yale Department of Surgery, Section of Otolaryngology, 333 Cedar Street, P.O. Box 208041, New Haven, CT 065208041, USA. Tel.: + 1 203 785 2181; fax: +1 203 785 3970. E-mail addresses: [email protected] (C.A. Schutt), [email protected] (J.F. Kveton). ☆☆
0196-0709/$ – see front matter © 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.amjoto.2013.11.002
258
AM ER IC AN JOUR NA L OF OTOLARY NG OLOG Y –H EA D A N D N E CK ME D I CI NE AN D SUR G E RY 3 5 ( 2 0 14 ) 25 7–2 6 0
low-salt diet and hydrochlorothiazide/triamterene was initiated. Medical treatment provided some relief of vertigo, but over 4 years, his left hearing loss progressed with continued imbalance and vertigo and a cochlear implant evaluation for his right profound loss was done. After passing implant criteria, MRI with gadolinium was obtained for surgical planning. T1 post-contrast images showed the presence of an enhancing mass in the right cochlea extending to the apical turn with additional involvement of the vestibule, saccule, and the superior and posterior semi-circular canals, consistent with an intravestibulocochlear schwannoma (Fig. 1). After the discussion with the patient resection of the schwannoma with immediate cochlear implantation was planned. Through a facial recess approach the basal turn of the cochlea was opened from the round window for 4–5 mm. The schwannoma filled the basal turn of the cochlea with apical extension and extension into the vestibule. The tumor was removed with meticulous microdissection and a Nucleus Freedom device (Cochlear: Macquarie Park, Australia) was inserted. Temporalis fascia was placed around the electrode along the exposed basal turn region. Postoperatively the patient had decreased complaints of tinnitus and vertigo, with excellent hearing results (Table 1; Fig. 2). The patient was able to use all electrodes of the cochlear implant without facial stimulation or pain. Yale IBR approval was obtained before the start of the investigation.
3.
Discussion
Intralabyrinthine schwannomas can be debilitating to patients, due to the significant hearing loss, tinnitus and vertigo they cause. Symptoms are hypothesized to occur in intracochlear pathology from the direct compression of the cochlear
Fig. 1 – (A) Axial T1 post-contrast image demonstrating the presence of cochlear and vestibular involvement. (B) Coronal T1 post-contrast image with visualization of an enhancing mass in the basal turn of the cochlea and apical extension. (C) Coronal T1 post-contrast image demonstrating involvement of the vestibule, common crus and extension into superior and posterior semicircular canals.
nerve [6,7]. When confined only to the vestibular system they are thought to decrease hearing by the production of endolymphatic hydrops, secondary to the compression of the ductus reunion and the saccule [1]. In both intracochlear and intravestibular schwannomas the tumor may change the metabolic milieu of the fluid within the inner ear, effecting hearing and balance, or directly cause impedance of fluid from a mass effect [3,7]. The intravestibulocochlear schwannoma encountered in our report may have caused hearing loss and vertigo secondary to any of the stated pathophysiologies. Importantly, no damage occurred to vital structures needed for cochlear implant candidacy. An intact spiral ganglion and nonpathologic cochlear nerve within the IAC were able to allow for the tonotopic transduction of sound. Our excellent hearing results are in agreement with the only other report to our knowledge of a cochlear implant after intralabyrinthine schwannoma resection [8]. Two other cochlear implants have been reported after resection of an IAC schwannoma with cochlear extension also achieving good hearing results [9–11]. Our report represents a large tumor with extensive involvement found to be present in only 5% of cases; however, implantation was still successful [5]. It is yet to be determined if smaller tumors or those limited to the vestibular system would have increased performance. If a patient's ability to receive a cochlear implant was questioned before resection, a promontory test could be performed. Comparison of results between implantation of intralabyrinthine and intracanalicular schwannomas has yet to be done. Anatomically, it is postulated that cochlear implants done after resection for an intralabyrinthine schawannoma will have improved performance in comparison due to the presence of an intact cochlear nerve with the absence of pathology from the spiral ganglion to the brain stem. The excellent hearing results found in our study and supported by the literature suggest that though further research is necessary, a new treatment paradigm may exist in the future. Currently, the rarity of the lesion prevents feasible analysis at a significant level. Most patients with this condition are serially monitored with MRI. Surgery occurs in only 7% to 47% of patients despite the presence of hearing loss and vertigo [2,3]. It is estimated that at presentation over 84% of patients with intralabyrinthine schwannomas have class D hearing by AAO guidelines [2]. Many of these may be candidates for cochlear implants. Importantly surgery should not be done in all patients, with a continued role for serial MRI and observation. The timing of implantation after resection still needs further assessment. As stated previously, the use of a cochlear implant in conjunction with this pathology has been reported in only one other instance. In that case the cochlear implant was not placed until 3 years after resection to assure diseasefree progression. The patient was only able to gain the use of apical electrodes as proximal electrodes were deactivated to reduce an unpleasant facial sensation. It is hypothesized that the widespread connective tissue found after delayed implantation allowed electrical spread [8]. Implantation was done directly after resection in our report with no complications allowing for full use of all electrodes. Immediate implantation seems necessary for optimal hearing results. This prevents postoperative tumor surveillance with MRI, but since
AM ER IC AN JOUR NA L OF OTOLARY NG OLOG Y –H EA D A N D N E CK ME D I CI N E AN D SUR G E RY 3 5 ( 2 0 14 ) 25 7–2 6 0
259
Fig. 2 – Preoperative and postoperative audiograms demonstrating hearing restoration.
intralabyrinthine schwannomas are slow growing, the possibility of significant recurrence is extremely low.
4.
by cochlear implantation. Our report demonstrates the ascertainment of good hearing results. Future treatment for this pathology may be done with awareness that auditory rehabilitation with cochlear implantation is possible.
Conclusion
In conclusion though difficult to study due to rarity, intralabyrinthine schwannomas are amenable to resection followed Table 1 – Hearing results reported per AAO guidelines. Hearing Preresults treatment PTA
Pretreatment WRS
Right ear 110 db Left ear 50 db
DNT 64%
Posttreatment PTA 25 db 40 db
Posttreatment WRS 84% 56%
REFERENCES
[1] Neff BA, Willcox Jr TO, Sataloff RT. Intralabyrinthine schwannomas. Otol Neurotol 2003;24:299–307. [2] Van Abel KM, Carlson ML, Link MJ, et al. Primary inner ear schwannomas: a case series and systematic review of the literature. Laryngoscope 2013;123:1957–66. [3] Kennedy RJ, Shelton C, Salzman KL, et al. Intralabyrinthine schwannomas: diagnosis, management, and a new classification system. Otol Neurotol Mar 2004;25: 160–7.
260
AM ER IC AN JOUR NA L OF OTOLARY NG OLOG Y –H EA D A N D N E CK ME D I CI NE AN D SUR G E RY 3 5 ( 2 0 14 ) 25 7–2 6 0
[4] Jackson LE, Hoffmann KK, Rosenberg SI. Intralabyrinthine schwannoma: subtle differentiating symptomatology. Otolaryngol Head Neck 2003;129:439–40. [5] Tieleman A, Casselman JW, Somers T, et al. Imaging of intralabyrinthine schwannomas: a retrospective study of 52 cases with emphasis on lesion growth. Am J Neuroradiol 2008;29:898–905. [6] Weed DT, Teague MW, Stewart R, et al. Intralabyrinthine schwannoma: a case report. Otolaryngol Head Neck 1994;111: 137–42. [7] DeLozier HL, Gacek RR, Dana ST. Intralabyrinthine schwannoma. Ann Otol Rhinol Laryngol 1979;88:187–91.
[8] Kronenberg J, Horowitz Z, Hildesheimer M. Intracochlear schwannoma and cochlear implantation. Ann Otol Rhinol Laryngol 1999;108:659–60. [9] Tono T, Ushisako Y, Morimitsu T. Cochlear implantation in an intralabyrinthine acoustic neuroma patient after resection of an intracanalicular tumor. Adv Otorhinolaryngol 1997;52:155–7. [10] Tono T, Ushisako Y, Morimitsu T. Cochlear implantation in an intralabyrinthine acoustic neuroma patient after resection of an intracanalicular tumor. J Laryngol Otol 1996;110:570–3. [11] Ahsan S, Telischi F, Hodges A, et al. Cochlear implantation concurrent with translabyrinthine acoustic neuroma resection. Laryngoscope 2003;113:472–4.
Available online at www.sciencedirect.com
ScienceDirect www.elsevier.com/locate/amjoto
Cochlear implantation after resection of an intralabyrinthine schwannoma☆,☆☆,★ Christopher A. Schutt, MD⁎, John F. Kveton, MD Yale Department of Surgery, Section of Otolaryngology, New Haven, CT, USA
ARTI CLE I NFO
A BS TRACT
Article history:
Intralabyrinthine schwannomas are rare tumors of the distal ends of the cochlear and
Received 18 October 2013
vestibular nerve. Their presence can be debilitating secondary to symptoms of hearing loss, vertigo, tinnitus, and imbalance. Currently, treatment to restore hearing in those who have become profoundly deaf is not attempted. Additionally, resection in patients with functioning hearing is rare, as the surgery assures deafness. We report the first case demonstrating the feasibility of resection of an intralabyrinthine schwannoma with immediate cochlear implantation. This technique addresses the patients hearing status by taking into account advancing technology, allowing for an improved quality of life. © 2014 Elsevier Inc. All rights reserved.
1.
Introduction
Intralabyrinthine schwannomas are a type of rare tumor that represents a distinct clinical entity, separate from vestibular schwannomas [1–3]. Common complaints include hearing loss, vertigo, tinnitus, imbalance and aural fullness [1,2]. Because symptoms mimic many neurotologic pathologies, especially Meniere's disease, there is often a delay to diagnosis. Fluctuating hearing is found in only 3% of tumors helping in differentiation [2,4]. The diagnosis of an intralabyrinthine schwannoma is made by MRI, showing enhancement in T1 post-gadolinium images [4]. T2 images may further delineate the extent of the mass through loss of fluid signal, caused by the presence of tumor [5]. Surgical removal has previously been reserved for patients with debilitating vertigo in a non-hearing ear, in those rare cases of tumor growth and when concern about pathologic diagnosis exists, since the invasive nature of the surgery assures deafness [3]. These
treatments have not taken into account advancing technologies such as cochlear implants. Our case demonstrates the value of surgical treatment in effort to decrease vertigo and tinnitus while restoring hearing though the resection of tumor with immediate cochlear implantation.
2.
Case report
A 65-year-old male was seen in consultation for severe vertigo with imbalance associated with moderate to severe left fluctuating hearing loss and aural fullness for 3 months. The patient experienced progressive right profound hearing loss over the prior 12 years. Tinnitus occurred in both ears but was more prominent on the right side. Vestibular-evoked myopotentials were absent bilaterally indicating a peripheral pathology, but caloric examination was normal. A diagnosis of bilateral Meniere's disease was made and treatment with a
☆
Funding source: None. Conflicts of interest: None. ★ Research support: None. ⁎ Corresponding author. Yale Department of Surgery, Section of Otolaryngology, 333 Cedar Street, P.O. Box 208041, New Haven, CT 065208041, USA. Tel.: + 1 203 785 2181; fax: +1 203 785 3970. E-mail addresses: [email protected] (C.A. Schutt), [email protected] (J.F. Kveton). ☆☆
0196-0709/$ – see front matter © 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.amjoto.2013.11.002
258
AM ER IC AN JOUR NA L OF OTOLARY NG OLOG Y –H EA D A N D N E CK ME D I CI NE AN D SUR G E RY 3 5 ( 2 0 14 ) 25 7–2 6 0
low-salt diet and hydrochlorothiazide/triamterene was initiated. Medical treatment provided some relief of vertigo, but over 4 years, his left hearing loss progressed with continued imbalance and vertigo and a cochlear implant evaluation for his right profound loss was done. After passing implant criteria, MRI with gadolinium was obtained for surgical planning. T1 post-contrast images showed the presence of an enhancing mass in the right cochlea extending to the apical turn with additional involvement of the vestibule, saccule, and the superior and posterior semi-circular canals, consistent with an intravestibulocochlear schwannoma (Fig. 1). After the discussion with the patient resection of the schwannoma with immediate cochlear implantation was planned. Through a facial recess approach the basal turn of the cochlea was opened from the round window for 4–5 mm. The schwannoma filled the basal turn of the cochlea with apical extension and extension into the vestibule. The tumor was removed with meticulous microdissection and a Nucleus Freedom device (Cochlear: Macquarie Park, Australia) was inserted. Temporalis fascia was placed around the electrode along the exposed basal turn region. Postoperatively the patient had decreased complaints of tinnitus and vertigo, with excellent hearing results (Table 1; Fig. 2). The patient was able to use all electrodes of the cochlear implant without facial stimulation or pain. Yale IBR approval was obtained before the start of the investigation.
3.
Discussion
Intralabyrinthine schwannomas can be debilitating to patients, due to the significant hearing loss, tinnitus and vertigo they cause. Symptoms are hypothesized to occur in intracochlear pathology from the direct compression of the cochlear
Fig. 1 – (A) Axial T1 post-contrast image demonstrating the presence of cochlear and vestibular involvement. (B) Coronal T1 post-contrast image with visualization of an enhancing mass in the basal turn of the cochlea and apical extension. (C) Coronal T1 post-contrast image demonstrating involvement of the vestibule, common crus and extension into superior and posterior semicircular canals.
nerve [6,7]. When confined only to the vestibular system they are thought to decrease hearing by the production of endolymphatic hydrops, secondary to the compression of the ductus reunion and the saccule [1]. In both intracochlear and intravestibular schwannomas the tumor may change the metabolic milieu of the fluid within the inner ear, effecting hearing and balance, or directly cause impedance of fluid from a mass effect [3,7]. The intravestibulocochlear schwannoma encountered in our report may have caused hearing loss and vertigo secondary to any of the stated pathophysiologies. Importantly, no damage occurred to vital structures needed for cochlear implant candidacy. An intact spiral ganglion and nonpathologic cochlear nerve within the IAC were able to allow for the tonotopic transduction of sound. Our excellent hearing results are in agreement with the only other report to our knowledge of a cochlear implant after intralabyrinthine schwannoma resection [8]. Two other cochlear implants have been reported after resection of an IAC schwannoma with cochlear extension also achieving good hearing results [9–11]. Our report represents a large tumor with extensive involvement found to be present in only 5% of cases; however, implantation was still successful [5]. It is yet to be determined if smaller tumors or those limited to the vestibular system would have increased performance. If a patient's ability to receive a cochlear implant was questioned before resection, a promontory test could be performed. Comparison of results between implantation of intralabyrinthine and intracanalicular schwannomas has yet to be done. Anatomically, it is postulated that cochlear implants done after resection for an intralabyrinthine schawannoma will have improved performance in comparison due to the presence of an intact cochlear nerve with the absence of pathology from the spiral ganglion to the brain stem. The excellent hearing results found in our study and supported by the literature suggest that though further research is necessary, a new treatment paradigm may exist in the future. Currently, the rarity of the lesion prevents feasible analysis at a significant level. Most patients with this condition are serially monitored with MRI. Surgery occurs in only 7% to 47% of patients despite the presence of hearing loss and vertigo [2,3]. It is estimated that at presentation over 84% of patients with intralabyrinthine schwannomas have class D hearing by AAO guidelines [2]. Many of these may be candidates for cochlear implants. Importantly surgery should not be done in all patients, with a continued role for serial MRI and observation. The timing of implantation after resection still needs further assessment. As stated previously, the use of a cochlear implant in conjunction with this pathology has been reported in only one other instance. In that case the cochlear implant was not placed until 3 years after resection to assure diseasefree progression. The patient was only able to gain the use of apical electrodes as proximal electrodes were deactivated to reduce an unpleasant facial sensation. It is hypothesized that the widespread connective tissue found after delayed implantation allowed electrical spread [8]. Implantation was done directly after resection in our report with no complications allowing for full use of all electrodes. Immediate implantation seems necessary for optimal hearing results. This prevents postoperative tumor surveillance with MRI, but since
AM ER IC AN JOUR NA L OF OTOLARY NG OLOG Y –H EA D A N D N E CK ME D I CI N E AN D SUR G E RY 3 5 ( 2 0 14 ) 25 7–2 6 0
259
Fig. 2 – Preoperative and postoperative audiograms demonstrating hearing restoration.
intralabyrinthine schwannomas are slow growing, the possibility of significant recurrence is extremely low.
4.
by cochlear implantation. Our report demonstrates the ascertainment of good hearing results. Future treatment for this pathology may be done with awareness that auditory rehabilitation with cochlear implantation is possible.
Conclusion
In conclusion though difficult to study due to rarity, intralabyrinthine schwannomas are amenable to resection followed Table 1 – Hearing results reported per AAO guidelines. Hearing Preresults treatment PTA
Pretreatment WRS
Right ear 110 db Left ear 50 db
DNT 64%
Posttreatment PTA 25 db 40 db
Posttreatment WRS 84% 56%
REFERENCES
[1] Neff BA, Willcox Jr TO, Sataloff RT. Intralabyrinthine schwannomas. Otol Neurotol 2003;24:299–307. [2] Van Abel KM, Carlson ML, Link MJ, et al. Primary inner ear schwannomas: a case series and systematic review of the literature. Laryngoscope 2013;123:1957–66. [3] Kennedy RJ, Shelton C, Salzman KL, et al. Intralabyrinthine schwannomas: diagnosis, management, and a new classification system. Otol Neurotol Mar 2004;25: 160–7.
260
AM ER IC AN JOUR NA L OF OTOLARY NG OLOG Y –H EA D A N D N E CK ME D I CI NE AN D SUR G E RY 3 5 ( 2 0 14 ) 25 7–2 6 0
[4] Jackson LE, Hoffmann KK, Rosenberg SI. Intralabyrinthine schwannoma: subtle differentiating symptomatology. Otolaryngol Head Neck 2003;129:439–40. [5] Tieleman A, Casselman JW, Somers T, et al. Imaging of intralabyrinthine schwannomas: a retrospective study of 52 cases with emphasis on lesion growth. Am J Neuroradiol 2008;29:898–905. [6] Weed DT, Teague MW, Stewart R, et al. Intralabyrinthine schwannoma: a case report. Otolaryngol Head Neck 1994;111: 137–42. [7] DeLozier HL, Gacek RR, Dana ST. Intralabyrinthine schwannoma. Ann Otol Rhinol Laryngol 1979;88:187–91.
[8] Kronenberg J, Horowitz Z, Hildesheimer M. Intracochlear schwannoma and cochlear implantation. Ann Otol Rhinol Laryngol 1999;108:659–60. [9] Tono T, Ushisako Y, Morimitsu T. Cochlear implantation in an intralabyrinthine acoustic neuroma patient after resection of an intracanalicular tumor. Adv Otorhinolaryngol 1997;52:155–7. [10] Tono T, Ushisako Y, Morimitsu T. Cochlear implantation in an intralabyrinthine acoustic neuroma patient after resection of an intracanalicular tumor. J Laryngol Otol 1996;110:570–3. [11] Ahsan S, Telischi F, Hodges A, et al. Cochlear implantation concurrent with translabyrinthine acoustic neuroma resection. Laryngoscope 2003;113:472–4.
