Eur Arch Otorhinolaryngol DOI 10.1007/s00405-014-3214-0
OTOLOGY
Endoscopic assisted cochlear implants in ear malformations Daniele Marchioni • Davide Soloperto • Maria C. Guarnaccia • Elisabetta Genovese Matteo Alicandri-Ciufelli • Livio Presutti
•
Received: 18 March 2014 / Accepted: 28 July 2014 Ó Springer-Verlag Berlin Heidelberg 2014
Abstract The aim of present study is to describe the use of the endoscopic assisted cochlear implant approach in cases with severely malformed temporal bones and with anomalous anatomy of the inner ear and tympanic cavity. Eight patients with malformed middle and inner ear and bilateral profound hearing loss were operated using an endoscopic assisted cochlear implant procedure at our tertiary university referral center between January and September 2013. Five patients received a cochlear implant using a suprameatal endoscopic assisted approach. A chart review of clinical data and videos from the operations was performed. All procedures were re-analyzed and codified. In all patients, discharge from hospital was on the third day post-surgery. No immediate or late postoperative complications were noted. The current mean follow-up is 6 months, with range between 4 and 12 months. This approach proved to be successful in cochlear implant placement. It guaranteed a very good control on the facial nerve, even in cases with difficult anatomical conditions, mainly thanks to the endoscopic procedure. It also permitted an appropriate anatomical orientation of the abnormal middle ear with a direct safe cochleostomy, when the round window position would have been difficult to treat using a traditional approach.
D. Marchioni D. Soloperto (&) M. C. Guarnaccia E. Genovese M. Alicandri-Ciufelli L. Presutti Otolaryngology Department, University Hospital of Modena, Via del Pozzo 71, 41100 Modena, Italy e-mail: [email protected]
Keywords Cochlear implant Charge syndrome Ear malformations Suprameatal endoscopic approach CT scan classification
Introduction Twenty percent of all cases of congenital profound hearing loss have bony abnormalities of the labyrinth [1]. More recent studies report this incidence to be even higher (30 %), because of improvements in high-resolution computed tomographic (CT) scanning techniques and an increased awareness of cochlear malformations, so an increasing number of cochlear implants are being performed in malformed cochleae [2]. The stage at which the embryonic development of the cochlea is arrested produces a malformation with a certain degree of severity, so a cochlear malformation may vary from total aplasia, severe cochlear hypoplasia, mild cochlear hypoplasia (basal turn only), common cavity, severe incomplete partition, and mild incomplete partition to a subnormal cochlea that does not reach a full 2.5 turns [1, 3]. The cochlear malformation may present with a variety of bony abnormalities of the vestibule or semicircular canals or an enlarged vestibular aqueduct, and an abnormal anatomy of the tympanic cavity could also be present. In these cases, correct exposure of the anatomical landmarks, with knowledge of the relationship between the anomalous middle ear structures, is crucial to perform a safe and successful surgical intervention avoiding facial nerve injury and yielding the correct location of the cochleostomy for array insertion. Furthermore, the high risk of Gusher in these patients [4] and the status of the cochlear nerve in the internal auditory canal (IAC) must be considered before surgery. The present work reports our first
123
123
Cochlear hybrid L24 CP810 processor (left) IAC internal auditory canal, SC semicircular canal, EVA enlarged vestibular aqueduct, RW round window, FN facial nerve
Normal Normal Cystic cochlea; enlarged vestibule; incomplete partition type 1 Normal Normal 71 5
Non syndromic
Cochlear REST CP810 processor (right) 4 4
Non syndromic
Malformed
Abnormal course
Common cavity
Abnormal site. Round window covered, prolapsed tegmen
Normal
MEDEL concerto proc. Opus2 (left) Normal Covered by mucosal web Hypoplastic cochlea 16 3
Right microtia/neck fistula, left cholesteatoma
Malformed
Abnormal course below cochleariform process
EVA Incomplete partition type II
Cochlear hybrid L24 CP810 processor (right) Normal Abnormal site Cystic cochlea, hypoplastic vestibule; absent SC; common cavity Normal Normal 3 2
Non syndromic
Normal Abnormal RW covered by FN Hypoplastic; absent SC; incomplete partition type II Abnormal course Malformed
Ossicular chain Syndrome Age (years) Patient
Table 1 Patient characteristics
Audiologic testing included auditory brainstem response (ABR) measurements, behavioral audiometry, speech perception and communicative skills evaluation in the children; pure tone audiometry threshold, speech audiometry and speech perception tests in the adults. All patients were evaluated wearing hearing aids and the results were compared with those obtained after cochlear implantation. Formal speech perception testing was performed only with cooperative patients; some patients were not evaluated with standardized tests because of the subjects’ young ages and developmental delays. All patients were submitted to speech therapist observation to evaluate perceptive skills and administration of the McArthur Questionnaire to parents to assess communicative skills in the children. The speech perception evaluation was administered to assess auditory behavior; in the children, it was conducted with speech therapy observation, and word recognition test. In adults, the evaluation was performed by tests for the identification and recognition of words. We assessed the auditory threshold with the cochlear implant and speech perception skills for all the children at the time of diagnosis and at 3-month follow-up after auditory rehabilitation.
Facial nerve
Audiologic assessment
CHARGE
Cochlea/vestibule
Round window
IAC
Between September 2006 and December 2013, 121 cochlear implantations were performed at the ENT Department of University Hospital of Modena. A complete audiologic and neuroradiologic preoperative assessment was performed to confirm the indications for surgery and to study middle and inner ear status. Among the 121 subjects who underwent cochlear implantation, eight patients had an inner ear malformation. Of these, five subjects underwent an endoscopic assisted cochlear implant (EACI). Between January and December 2013, a chart and video review of those five operations was performed. Intraoperative anatomic findings and the degree of implant insertion were recorded, as well any surgical complications encountered during this approach. Based on the CT scan findings, all inner and middle ear malformations were analyzed and classified. A brain MRI exam was always performed, to check the cochlear nerve status. According to the classification by Sennaroglu and Saatci [3], these malformations represented varying degrees of abnormality. Patient characteristics are shown in Table 1.
4
Materials and methods
1
Cochlear implant
experience using an endoscopic assisted cochlear implants (EACI) in malformed ears.
MEDEL concerto proc. Opus2 (right)
Eur Arch Otorhinolaryngol
Eur Arch Otorhinolaryngol
Fig. 1 (patient number 3) Endoscopic approach. Left ear. a Endoscopic view of the tympanic eardrum, a 0° endoscope, 15 cm length, was used through the external auditory canal to create a tympanomeatal flap. b Endoscopic view of the tympanic cavity after tympanomeatal flap elevation. A malformed ear was detected; note the anomalous ossicular chain associated with a descending tympanic segment of the facial nerve. c Endoscopic detail of the anatomy of the
promontory region; a hypoplastic oval window is visible, the round window niche is also hypoplastic and covered by a microfold. d Endoscopic magnification of the tympanic segment of the facial nerve; the nerve is dehiscent with anomalous course, running under the cochleariform process. fn facial nerve, rw round window, ow oval window, lsc lateral semicircular canal, pe pyramidal eminence, pr promontory, cp cochleariform process
Surgical technique
evaluated (Fig. 2a, b). A diamond burr was used to remove the tegmen, to have a good exposure of the round window to perform an endoscopic cochleostomy. After optimal exposure of the membrane of the round window, a micro-hook was used to open the membrane, creating access to the scala tympani (Fig. 2c, d). After this surgical step, a piece of gel foam was placed on the cochleostomy site. When an unfavorable anatomical condition was found and the round window was inaccessible, a promontorial cochleostomy was performed, for example, when an anomalous course of the facial nerve over the round window niche was present, hiding the round window niche (Fig. 3a, b). In these cases, the promontorial cochleostomy maintained the facial nerve and round window niche under endoscopic control to avoid injury to the nerve. The cochleostomy was performed just anteriorly and inferiorly to the round window, carefully opening the scala tympani (Fig. 3c, d). A piece of gel foam was placed on the cochleostomy site.
Endoscopic steps A 0° endoscope, 15 cm in length, was inserted into the external auditory canal and used to create a tympanomeatal flap. This flap was elevated under endoscopic view, entering into the tympanic cavity (Fig. 1a, b). The flap was then pulled anteriorly, until the posterior border of the malleus was identifiable (Fig. 1b). After the creation of the tympanomeatal flap, an endoscopic check of the anatomical structures in the tympanic cavity was made (Fig. 1c, d). When an abnormal course of the facial nerve was found, the relationship of the nerve to the ossicular structures, round window niche and promontory was noted. Once the surgeon had clarified the anatomical relationship between the surrounding structures of the middle ear, the round window niche was identified and its accessibility
123
Eur Arch Otorhinolaryngol
Fig. 2 (patient number 5) Endoscopic transcanal approach to the round window niche and cochleostomy. Left ear. a Endoscopic view of the tympanic cavity after tympanomeatal flap elevation; b the round window niche was detected endoscopically, exposing all the surrounding anatomical structures and the round window membrane. c The tegmen and pillars of the round window niche were gently removed, and the membrane opened by performing a cochleostomy,
entering into the scala tympani. d Endoscopic magnification of the scala tympani. fn facial nerve, rw round window, pe pyramidal eminence, pr promontory, cp cochleariform process, ma malleus, s stapes, in incus, te tegmen, ap anterior pillar, pp posterior pillar, f finiculus, su subiculum, ac area concamerata, fu fustis, ts scala tympani
Microscopic steps
spaces (Fig. 4b). In cases where the mastoid air cells were well represented, a limited posterior tympanotomy was performed, to enlarge the surgical space for array introduction, and maintaining the integrity of the ossicles. The receiver–stimulator of the implant was fixed and covered under the temporalis muscle (Fig. 4c). The array was gently pushed through the passage which had been created, from the epitympanum into the mesotympanum; the array was then covered and gently inserted into the cochleostomy, through the external auditory canal (Fig. 4d). Intraoperative radiography was then performed to confirm the position of the array. A small piece of temporalis fascia was used with fibrin glue to seal the cochleostomy. The tympanomeatal flap was replaced and the external auditory canal was packed with fragments of gel foam. The subperiosteal flap was used to cover the receiver body and the retroauricular skin incision was sutured.
A retroauricular skin incision was made, identifying the plane of the temporal muscle fascia; a posterior periosteal flap was created and elevated, uncovering the mastoid bone. When mastoid cells were present and a deformity of the ossicles and facial nerve was not found, the surgical steps were performed in the same manner as in the suprameatal approach. An antrotomy, with an anterior atticotomy, was performed, using classic landmarks and maintaining the posterior wall of the external auditory canal (Fig. 4a). The anterior atticotomy proceeded through the suprameatal route until the incudo-malleolar joint and the anterior attic were exposed. When mastoid air cells were absent and there was insufficient space through the suprameatal route, the incus was removed, creating a wide connection between the posterior epitympanum and the mesotympanic
123
Eur Arch Otorhinolaryngol
Fig. 3 (patient number 1) Endoscopic approach. Right ear. a The tympanomeatal flap was elevated, and a malformed ear was detected; in this subject, an anomalous ossicular chain was observed; the facial nerve runs below the stapes on the promontory. b Endoscopic magnification of tympanic segment of the facial nerve. The nerve is dehiscent and runs below the stapes and over the round window niche
obscuring the round window. c Since the facial nerve obscured the round window, a promontorial cochleostomy was performed under endoscopic view, maintaining the anatomical landmarks under surgical control. d Endoscopic magnification on the promontorial cochleostomy. fn facial nerve, rw round window, ma malleus, s stapes, in incus, cp cochleariform process, ct chorda tympani
Fig. 4 (patient number 1) Microscopic suprameatal approach. Right ear. a A mastoid tunnel was drilled on the sclerotic mastoid identifying the dura of the middle cranial fossa superiorly, and maintaining the posterior wall of the external auditory canal. The mastoid bone was removed until the antrum and the epitympanum were exposed and the incus was detected. b The incus was removed,
creating a connection between the posterior epitympanum and the mesotympanic spaces. c The placement for the receiver–stimulator of the implant was created. d The array was introduced into the cochleostomy created previously through the suprameatal route. A piece of temporalis fascia was used to seal the cochleostomy
123
Eur Arch Otorhinolaryngol
Results Out of five subjects, two were male and three female (3 pediatric and 2 adult patients); mean age was 19.6 (range 3–71). During the radiological assessment, we noted the anatomical conformation of the middle and inner ear. In 3/5 subjects, an anomalous course of the facial nerve was found, detected by CT scan (Fig. 5), and in all five subjects, a malformed inner ear was present (Fig. 6). Regarding the inner ear malformations in these five subjects, on the basis of the Sennaroglu classification, we observed an Incomplete partition type I in one subject; an Incomplete partition type II in two subjects and a Common cavity in two subjects (Table 1). Middle ear endoscopic findings In all subjects, the endoscopic approach allowed us to recognize the anatomical conformation of the tympanic cavity. Regarding the malformations of the middle ear, we observed an anomalous course of the facial nerve in 3/5 subjects; in
Fig. 5 (patient number 1) Preoperative CT scan in subject with malformed middle ear (subject affected by CHARGE syndrome). a Axial view. A sclerotic mastoid (black triangle) without antrum cell, the epitympanic space is present with an anomalous incudomalleolar joint. b Axial view. Anomalous course of the tympanic segment of the facial nerve (white triangle) covering the round
123
one of these cases where a CHARGE syndrome (patient number 1) was detected, an aberrant course of the facial nerve was found, the nerve was dehiscent and located under the stapes over the promontory, obscuring the round window niche. In patient number 3, the round window was hidden and surgically inaccessible, due to displacement of the facial nerve; an anomalous course of the tympanic segment of the facial nerve was found, in association with a hypoplastic oval window; in this case, the nerve was dehiscent, partially covering the oval window and running below the cochleariform process. Patient number 4 presented a dehiscent tympanic segment of the facial nerve. In 3/5 subjects, an anomalous conformation or anatomical position of the round window membrane and niche was found. In 2/3 subjects (patient number 2 and 4), the niche of the round window was situated in a more cranial position and a tegmen removal was necessary to detect the membrane. In 1/4 subjects (patient number 1), because of the presence of an anomalous course of the facial nerve, the round window was covered by the nerve running below the oval window and ossicles, across the promontory.
window. c From analysis of the CT scan in the coronal view, the facial nerve runs over the promontory (white triangle) and over the round window niche (white arrow). d Coronal view. The cochlear nerve was detected in an anomalous position; aplasia of the nerve is suspected (black arrow)
Eur Arch Otorhinolaryngol Fig. 6 (patient number 2) Preoperative CT scan of subject with malformed inner ear (incomplete partition type I). a, b Axial view. The mastoid is pneumatised and ossicles are present. A malformed inner ear is visible: Aplasia of the semicircular canals with hypoplastic aspect of the vestibule is detected. c, d Coronal view. The normal partition in the cochlear spiral is absent, so the cochlea appears only as a single cavity. Bilaterally it looks like an empty cystic space and in a lateral position with respect to the promontory
Regarding the ossicles, in 3/5 subjects, a normoarticulated ossicular chain was present; in 2/3 subjects, an anomalous ossicular chain was found. In the patient affected by CHARGE syndrome (patient number 1), the stapes was fused with the long process of the incus, and in patient number 3, a rudimental incus and malleus were found in association with a hypoplastic oval window. Surgical approach In all five subjects, we were able to perform endoscopic assisted surgery. Endoscopic approach Direct endoscopic control of anatomical structures such as the facial nerve, the round window niche, the promontory and ossicles was achieved in all subjects, allowing the cochleostomy to be performed using the endoscopic approach. In four subjects, an endoscopic cochleostomy was performed through the round window niche; in two subjects, the round window membrane was found to be in an anomalous position. In 3/4 subjects, the tegmen of the round window niche was regularized with a diamond burr, until the round window membrane was identified. In one of these cases, a double membrane on the niche of the round window was detected and removed.
In one subject, a round window membrane was exposed endoscopically, without any drilling procedure. As a result of facial nerve displacement on the round window, a promontorial cochleostomy was performed in 1/5 subjects (patient number 1); in this case, drilling of the promontory area was performed just anteriorly and inferiorly with the respect of the round window, entering into the scala tympani and avoiding damage to the facial nerve (Fig. 3c, d). No intraoperative gusher was found in any subject. Microscopic approach In 3/5 subjects, a suprameatal approach was used due the presence of a sclerotic mastoid. In 2/3 of these subjects, as a result of the epitympanic conformation, incus removal was necessary to obtain a direct connection between the suprameatal route and the mesotympanic spaces. In 2/5 subjects, where normal mastoid air cells were present in association with a normal course of the facial nerve, a posterior tympanotomy was performed. In all cases, the receiver–stimulator of the implant was fixed and covered under the temporalis muscle. In 5/5 subjects, array insertion was performed through the cochleostomy previously created, without any problems. Neural responses were tested confirming the correct insertion of the electrode. In all subjects, a small piece of temporalis fascia was used with fibrin glue to seal the
123
Eur Arch Otorhinolaryngol
cochleostomy. A radiologic intraoperative X-ray was performed in all cases to verify the correct insertion of the electrode. All patients underwent an intraoperative facial nerve monitoring (NIM). Complications No intraoperative complications were observed in this series. In all subjects, discharge from hospital was usually on the third day postoperatively. No postoperative complications were noted. At present, the mean follow-up time is 6 months (range 4–12 months) and no complications have been reported. Audiologic results All patients exhibited profound hearing loss at preoperative evaluation. All of the implanted children showed varying degrees of auditory benefit as measured by routine audiometry and speech perception tests.
Discussion Middle/inner ear malformations present technical problems for cochlear implant surgery, most notably an anomalous course of the facial nerve may be present in these patients, and cerebrospinal fluid (CSF) gusher may be expected [5, 6]. Iatrogenic damage to the facial nerve is still a major surgical complication after cochlear implantation and anatomical exposure of the round window through posterior tympanotomy could be a problem in patients with cochleo-vestibular malformations, such as in syndromic patients. Sennaroglu et al. [7] reported their surgical results for cochlear implantation in malformed cochlea. From this experience, the authors stated that, during cochlear implantations in malformed ears, the standard mastoidectomy with a facial recess approach could be adopted, but the surgical approach must be tailored according to anatomical findings in individual patients. The surgeon must be ready to modify the surgical approach during surgery and in cases with difficult anatomy, a canal wall down technique might be used to identify the anatomical landmarks avoiding injury to the facial nerve. Some authors have suggested a subtotal petrosectomy approach, to obtain a better view of the surgical field. Free et al. [8] suggested subtotal petrosectomy in middle ear malformations to help identify available landmarks, if possible. Furthermore, the risk of developing meningitis during their lifetime is higher in subjects with inner ear malformations than in the normal population, even without CI surgery. In their experience with subtotal petrosectomy, they reported two middle ear malformations treated with this technique for CI; one of
123
these two procedures was complicated by a subcutaneous collection of CSF, postoperatively treated with sterile puncture and head bandage for 7 days. In our opinion, subtotal petrosectomy could be a good choice when an intraoperative CSF leakage/gusher has occurred and surgical management has been difficult. In these specific cases, this approach could allow better control of the CSF leakage, through obliteration of the Eustachian tube orifice and cavity, but some risks, related to the surgical procedure should be considered. First of all, the possibility of fat infection could be very dangerous, if the possible consequent infection spreads through the cochleostomy and develops into meningitis. Then, there is the possibility of entrapped cholesteatoma in the obliterated cavity. For this reason, prolonged postoperative follow-up is required (only a CT scan can be planned, as there is no possibility of performing MRI) and a staged procedure may be performed. To prevent facial paralysis and injury to the chorda tympani, other authors [9–11] have developed an alternative technique in which the electrode of the cochlear implant is introduced into the middle ear via a suprameatal route, in contrast to classic mastoidectomy with the posterior tympanotomy approach. This suprameatal approach differs from the classic approach in avoiding a mastoidectomy, so the facial nerve is protected by the body of the incus when the middle ear is entered by drilling the suprameatal tunnel. In recent years, the endoscopic approach to the tympanic cavity has improved, giving better knowledge of the anatomical structures and permitting a minimally invasive approach for selective diseases located in the tympanic cavity such as attic cholesteatoma [12–14]. When an unfavorable anatomical condition was detected during radiologic exam in the preoperative period in subjects who were candidates for cochlear implants, we started to use the endoscopic approach to magnify and identify the anatomy of the tympanic cavity. This series represents the first experience with endoscopic assisted surgery for malformed ears. In our series, we adopted a transcanalar approach to reach the tympanic cavity and to recognize the tympanic cavity endoscopically and we performed the cochleostomy under endoscopic control. The second part of the surgery was performed under microscopic view, creating a suprameatal or transmastoid facial recess route to reach the tympanic cavity, based on the characteristics of the mastoid on CT scan. Since the main issue in cochlear implants in malformed ears is correct exposure of the anatomical structures to obtain anatomical landmarks thus avoiding facial nerve injury and performing a correct cochleostomy for array insertion, we started to use the endoscopic approach routinely. The advantages of this technique can be so highlighted. First of all, endoscopic procedure helps the surgeon to recognize the anomalous anatomy of the tympanic cavity and the surrounding
Eur Arch Otorhinolaryngol
Fig. 7 (patient number 2) Transcanal endoscopic approach. Right ear. a After tympanomeatal flap elevation, the round window niche and membrane were endoscopically detected; b A diamond burr was used under endoscopic view to enlarge the niche of the round window, uncovering the round window membrane. c Endoscopic view of the round window membrane; the membrane was located
cranially in an anomalous position, close to the oval window and stapes. d Microscopic step. A transmastoid approach was performed maintaining the integrity of the external auditory canal; array insertion was carried out through the mastoid route into the cochleostomy previously created. rw round window, ma malleus, s stapes, in incus, ct chorda tympani
anatomical structures, thus performing a safe cochleostomy, especially in case of an abnomalous facial nerve course. The possibility of ‘‘looking around the corner’’ and the magnification of the structures using the endoscopic approach permit to explore the tympanic cavity and to check all anatomical features. The endoscopic step also permitted the transmastoid/suprameatal microscopic step to be performed more safely even in subjects with unfavorable conditions such as a sclerotic mastoid, by knowing the exact location of the anatomical structures going into the tympanic cavity such as the course of the facial nerve. Finally, it’s possible to preserve the integrity of the posterior canal wall and to have a direct exposure of the tympanic cavity anatomy (Fig. 7a–d), avoiding subtotal petrosectomy or an open approach as some authors have suggested for the treatment of malformed ears. No minor or major complications were observed in our series. Regard to audiologic results, owing to the unpredictable distribution of neural tissue in inner ear anomalies, the final outcome after implantation is not predictable in these patients. For these reasons, despite the challenging surgical approach adopted to position the electrodes correctly, the audiologic results could be lower than expected and not comparable
with respect to subjects with a normal anatomy, so the development of a surgical technique with low morbidity and with a minimally invasive approach should be considered in these subjects.
Conclusion From this preliminary report, endoscopic support is recommended especially when difficult anatomy is expected in candidates for cochlear implantation. Where the anatomical conditions are unfavorable for traditional transmastoid, facial recess surgery, such as in CHARGE syndrome or other conditions of ear abnormalities, an endoscopic transcanalar approach to the round window niche should be attempted. In contrast to the traditional microscopic approach, it allows better identification of promontorial structures, in particular, in malformed ears. This technique may also have applications within the field of cochlear and facial malformation, where traditional techniques and also neuroradiological investigations do not always provide satisfactory answers to the needs of the patient and the otosurgeon. Owing to the small number of
123
Eur Arch Otorhinolaryngol
subjects, further studies will also be necessary and each new technique introduced into surgery, possibly representing an advance in the ongoing process of development of scientific knowledge, always requires long-term validation and lengthy follow-up, designed to test possible criticality and confirm the results. Acknowledgments These cases were derived from the Otolaryngology Department, University Hospital of Modena. Conflict of interest All of the authors have read and approved the manuscript. None of them have any financial relationships to disclose.
References 1. Jackler RK, Luxford WM, House WF (1987) Congenital malformations of the inner ear: a classification based on embryogenesis. Laryngoscope 97:2–14 2. McClay JE, Tandy R, Grundfast K et al (2002) Major and minor temporal bone abnormalities in children with and without congenital sensorineural hearing loss. Arch Otolaryngol Head Neck Surg 128:664–671 3. Sennaroglu L, Saatci I (2002) A new classification for cochleovestibular malformations. Laryngoscope 112:2230–2241 4. Mylanus EAM, Rotteveel LJC, Leeuw RL (2004) Congenital malformation of the inner ear and pediatric cochlear implantation. Otol Neurotol 25:308–317 5. Hoffman RA, Downey LL, Waltzman SB, Cohen NL (1997) Cochlear implantation in children with cochlear malformations. Am J Otol 18:184–187
123
6. Graham JM, Phelps PD, Michaels L (2000) Congenital malformations of the ear and cochlear implantation in children: review and temporal bone report of common cavity. J Laryngol Otol Suppl 25:1–14 7. Sennaroglu L, Sarac S, Ergin T (2006) Surgical results of cochlear implantation in malformed cochlea. Otol Neurotol 27:615–623 8. Free R, Falcioni M, Di Trapani G, Giannuzzi A, Russo A, Sanna M (2013) The role of subtotal petrosectomy in cochlear implant surgery—a report of 32 cases and review on indications. Otol Neurotol 34:1033–1040 9. Kronenberg J, Migirov L, Dagan T (2001) Suprameatal approach: new surgical approach for cochlear implantation. J Laryngol Otol 115:283–285 10. Kronenberg J, Migirov L, Baumgartner WD (2004) The suprameatal approach in cochlear implant surgery: an alternative surgical approach to cochlear implantation. Otol Neurotol 25:41–44 11. Postelmans J, Van Spronsen E, Grolman W et al (2011) An evaluation of preservation of residual hearing using the suprameatal approach for cochlear implantation: can this implantation technique be used for preservation of residual hearing? Laryngoscope 121:1794–1799 12. Marchioni D, Alicandri-Ciufelli M, Piccinini A, Genovese E, Presutti L (2010) Inferior retrotympanum revisited: an endoscopic anatomic study. Laryngoscope 120(9):1880–1886 13. Marchioni D, Villari D, Mattioli F, Alicandri-Ciufelli M, Piccinini A, Presutti L (2013) Endoscopic management of attic cholesteatoma: a single-institution experience. Otolaryngol Clin North Am 46(2):201–209 14. Marchioni D, Grammatica A, Alicandri-Ciufelli M, Genovese E, Presutti L (2014) Endoscopic cochlear implant procedure. Eur Arch Otorhinolaryngol 271:959–966
OTOLOGY
Endoscopic assisted cochlear implants in ear malformations Daniele Marchioni • Davide Soloperto • Maria C. Guarnaccia • Elisabetta Genovese Matteo Alicandri-Ciufelli • Livio Presutti
•
Received: 18 March 2014 / Accepted: 28 July 2014 Ó Springer-Verlag Berlin Heidelberg 2014
Abstract The aim of present study is to describe the use of the endoscopic assisted cochlear implant approach in cases with severely malformed temporal bones and with anomalous anatomy of the inner ear and tympanic cavity. Eight patients with malformed middle and inner ear and bilateral profound hearing loss were operated using an endoscopic assisted cochlear implant procedure at our tertiary university referral center between January and September 2013. Five patients received a cochlear implant using a suprameatal endoscopic assisted approach. A chart review of clinical data and videos from the operations was performed. All procedures were re-analyzed and codified. In all patients, discharge from hospital was on the third day post-surgery. No immediate or late postoperative complications were noted. The current mean follow-up is 6 months, with range between 4 and 12 months. This approach proved to be successful in cochlear implant placement. It guaranteed a very good control on the facial nerve, even in cases with difficult anatomical conditions, mainly thanks to the endoscopic procedure. It also permitted an appropriate anatomical orientation of the abnormal middle ear with a direct safe cochleostomy, when the round window position would have been difficult to treat using a traditional approach.
D. Marchioni D. Soloperto (&) M. C. Guarnaccia E. Genovese M. Alicandri-Ciufelli L. Presutti Otolaryngology Department, University Hospital of Modena, Via del Pozzo 71, 41100 Modena, Italy e-mail: [email protected]
Keywords Cochlear implant Charge syndrome Ear malformations Suprameatal endoscopic approach CT scan classification
Introduction Twenty percent of all cases of congenital profound hearing loss have bony abnormalities of the labyrinth [1]. More recent studies report this incidence to be even higher (30 %), because of improvements in high-resolution computed tomographic (CT) scanning techniques and an increased awareness of cochlear malformations, so an increasing number of cochlear implants are being performed in malformed cochleae [2]. The stage at which the embryonic development of the cochlea is arrested produces a malformation with a certain degree of severity, so a cochlear malformation may vary from total aplasia, severe cochlear hypoplasia, mild cochlear hypoplasia (basal turn only), common cavity, severe incomplete partition, and mild incomplete partition to a subnormal cochlea that does not reach a full 2.5 turns [1, 3]. The cochlear malformation may present with a variety of bony abnormalities of the vestibule or semicircular canals or an enlarged vestibular aqueduct, and an abnormal anatomy of the tympanic cavity could also be present. In these cases, correct exposure of the anatomical landmarks, with knowledge of the relationship between the anomalous middle ear structures, is crucial to perform a safe and successful surgical intervention avoiding facial nerve injury and yielding the correct location of the cochleostomy for array insertion. Furthermore, the high risk of Gusher in these patients [4] and the status of the cochlear nerve in the internal auditory canal (IAC) must be considered before surgery. The present work reports our first
123
123
Cochlear hybrid L24 CP810 processor (left) IAC internal auditory canal, SC semicircular canal, EVA enlarged vestibular aqueduct, RW round window, FN facial nerve
Normal Normal Cystic cochlea; enlarged vestibule; incomplete partition type 1 Normal Normal 71 5
Non syndromic
Cochlear REST CP810 processor (right) 4 4
Non syndromic
Malformed
Abnormal course
Common cavity
Abnormal site. Round window covered, prolapsed tegmen
Normal
MEDEL concerto proc. Opus2 (left) Normal Covered by mucosal web Hypoplastic cochlea 16 3
Right microtia/neck fistula, left cholesteatoma
Malformed
Abnormal course below cochleariform process
EVA Incomplete partition type II
Cochlear hybrid L24 CP810 processor (right) Normal Abnormal site Cystic cochlea, hypoplastic vestibule; absent SC; common cavity Normal Normal 3 2
Non syndromic
Normal Abnormal RW covered by FN Hypoplastic; absent SC; incomplete partition type II Abnormal course Malformed
Ossicular chain Syndrome Age (years) Patient
Table 1 Patient characteristics
Audiologic testing included auditory brainstem response (ABR) measurements, behavioral audiometry, speech perception and communicative skills evaluation in the children; pure tone audiometry threshold, speech audiometry and speech perception tests in the adults. All patients were evaluated wearing hearing aids and the results were compared with those obtained after cochlear implantation. Formal speech perception testing was performed only with cooperative patients; some patients were not evaluated with standardized tests because of the subjects’ young ages and developmental delays. All patients were submitted to speech therapist observation to evaluate perceptive skills and administration of the McArthur Questionnaire to parents to assess communicative skills in the children. The speech perception evaluation was administered to assess auditory behavior; in the children, it was conducted with speech therapy observation, and word recognition test. In adults, the evaluation was performed by tests for the identification and recognition of words. We assessed the auditory threshold with the cochlear implant and speech perception skills for all the children at the time of diagnosis and at 3-month follow-up after auditory rehabilitation.
Facial nerve
Audiologic assessment
CHARGE
Cochlea/vestibule
Round window
IAC
Between September 2006 and December 2013, 121 cochlear implantations were performed at the ENT Department of University Hospital of Modena. A complete audiologic and neuroradiologic preoperative assessment was performed to confirm the indications for surgery and to study middle and inner ear status. Among the 121 subjects who underwent cochlear implantation, eight patients had an inner ear malformation. Of these, five subjects underwent an endoscopic assisted cochlear implant (EACI). Between January and December 2013, a chart and video review of those five operations was performed. Intraoperative anatomic findings and the degree of implant insertion were recorded, as well any surgical complications encountered during this approach. Based on the CT scan findings, all inner and middle ear malformations were analyzed and classified. A brain MRI exam was always performed, to check the cochlear nerve status. According to the classification by Sennaroglu and Saatci [3], these malformations represented varying degrees of abnormality. Patient characteristics are shown in Table 1.
4
Materials and methods
1
Cochlear implant
experience using an endoscopic assisted cochlear implants (EACI) in malformed ears.
MEDEL concerto proc. Opus2 (right)
Eur Arch Otorhinolaryngol
Eur Arch Otorhinolaryngol
Fig. 1 (patient number 3) Endoscopic approach. Left ear. a Endoscopic view of the tympanic eardrum, a 0° endoscope, 15 cm length, was used through the external auditory canal to create a tympanomeatal flap. b Endoscopic view of the tympanic cavity after tympanomeatal flap elevation. A malformed ear was detected; note the anomalous ossicular chain associated with a descending tympanic segment of the facial nerve. c Endoscopic detail of the anatomy of the
promontory region; a hypoplastic oval window is visible, the round window niche is also hypoplastic and covered by a microfold. d Endoscopic magnification of the tympanic segment of the facial nerve; the nerve is dehiscent with anomalous course, running under the cochleariform process. fn facial nerve, rw round window, ow oval window, lsc lateral semicircular canal, pe pyramidal eminence, pr promontory, cp cochleariform process
Surgical technique
evaluated (Fig. 2a, b). A diamond burr was used to remove the tegmen, to have a good exposure of the round window to perform an endoscopic cochleostomy. After optimal exposure of the membrane of the round window, a micro-hook was used to open the membrane, creating access to the scala tympani (Fig. 2c, d). After this surgical step, a piece of gel foam was placed on the cochleostomy site. When an unfavorable anatomical condition was found and the round window was inaccessible, a promontorial cochleostomy was performed, for example, when an anomalous course of the facial nerve over the round window niche was present, hiding the round window niche (Fig. 3a, b). In these cases, the promontorial cochleostomy maintained the facial nerve and round window niche under endoscopic control to avoid injury to the nerve. The cochleostomy was performed just anteriorly and inferiorly to the round window, carefully opening the scala tympani (Fig. 3c, d). A piece of gel foam was placed on the cochleostomy site.
Endoscopic steps A 0° endoscope, 15 cm in length, was inserted into the external auditory canal and used to create a tympanomeatal flap. This flap was elevated under endoscopic view, entering into the tympanic cavity (Fig. 1a, b). The flap was then pulled anteriorly, until the posterior border of the malleus was identifiable (Fig. 1b). After the creation of the tympanomeatal flap, an endoscopic check of the anatomical structures in the tympanic cavity was made (Fig. 1c, d). When an abnormal course of the facial nerve was found, the relationship of the nerve to the ossicular structures, round window niche and promontory was noted. Once the surgeon had clarified the anatomical relationship between the surrounding structures of the middle ear, the round window niche was identified and its accessibility
123
Eur Arch Otorhinolaryngol
Fig. 2 (patient number 5) Endoscopic transcanal approach to the round window niche and cochleostomy. Left ear. a Endoscopic view of the tympanic cavity after tympanomeatal flap elevation; b the round window niche was detected endoscopically, exposing all the surrounding anatomical structures and the round window membrane. c The tegmen and pillars of the round window niche were gently removed, and the membrane opened by performing a cochleostomy,
entering into the scala tympani. d Endoscopic magnification of the scala tympani. fn facial nerve, rw round window, pe pyramidal eminence, pr promontory, cp cochleariform process, ma malleus, s stapes, in incus, te tegmen, ap anterior pillar, pp posterior pillar, f finiculus, su subiculum, ac area concamerata, fu fustis, ts scala tympani
Microscopic steps
spaces (Fig. 4b). In cases where the mastoid air cells were well represented, a limited posterior tympanotomy was performed, to enlarge the surgical space for array introduction, and maintaining the integrity of the ossicles. The receiver–stimulator of the implant was fixed and covered under the temporalis muscle (Fig. 4c). The array was gently pushed through the passage which had been created, from the epitympanum into the mesotympanum; the array was then covered and gently inserted into the cochleostomy, through the external auditory canal (Fig. 4d). Intraoperative radiography was then performed to confirm the position of the array. A small piece of temporalis fascia was used with fibrin glue to seal the cochleostomy. The tympanomeatal flap was replaced and the external auditory canal was packed with fragments of gel foam. The subperiosteal flap was used to cover the receiver body and the retroauricular skin incision was sutured.
A retroauricular skin incision was made, identifying the plane of the temporal muscle fascia; a posterior periosteal flap was created and elevated, uncovering the mastoid bone. When mastoid cells were present and a deformity of the ossicles and facial nerve was not found, the surgical steps were performed in the same manner as in the suprameatal approach. An antrotomy, with an anterior atticotomy, was performed, using classic landmarks and maintaining the posterior wall of the external auditory canal (Fig. 4a). The anterior atticotomy proceeded through the suprameatal route until the incudo-malleolar joint and the anterior attic were exposed. When mastoid air cells were absent and there was insufficient space through the suprameatal route, the incus was removed, creating a wide connection between the posterior epitympanum and the mesotympanic
123
Eur Arch Otorhinolaryngol
Fig. 3 (patient number 1) Endoscopic approach. Right ear. a The tympanomeatal flap was elevated, and a malformed ear was detected; in this subject, an anomalous ossicular chain was observed; the facial nerve runs below the stapes on the promontory. b Endoscopic magnification of tympanic segment of the facial nerve. The nerve is dehiscent and runs below the stapes and over the round window niche
obscuring the round window. c Since the facial nerve obscured the round window, a promontorial cochleostomy was performed under endoscopic view, maintaining the anatomical landmarks under surgical control. d Endoscopic magnification on the promontorial cochleostomy. fn facial nerve, rw round window, ma malleus, s stapes, in incus, cp cochleariform process, ct chorda tympani
Fig. 4 (patient number 1) Microscopic suprameatal approach. Right ear. a A mastoid tunnel was drilled on the sclerotic mastoid identifying the dura of the middle cranial fossa superiorly, and maintaining the posterior wall of the external auditory canal. The mastoid bone was removed until the antrum and the epitympanum were exposed and the incus was detected. b The incus was removed,
creating a connection between the posterior epitympanum and the mesotympanic spaces. c The placement for the receiver–stimulator of the implant was created. d The array was introduced into the cochleostomy created previously through the suprameatal route. A piece of temporalis fascia was used to seal the cochleostomy
123
Eur Arch Otorhinolaryngol
Results Out of five subjects, two were male and three female (3 pediatric and 2 adult patients); mean age was 19.6 (range 3–71). During the radiological assessment, we noted the anatomical conformation of the middle and inner ear. In 3/5 subjects, an anomalous course of the facial nerve was found, detected by CT scan (Fig. 5), and in all five subjects, a malformed inner ear was present (Fig. 6). Regarding the inner ear malformations in these five subjects, on the basis of the Sennaroglu classification, we observed an Incomplete partition type I in one subject; an Incomplete partition type II in two subjects and a Common cavity in two subjects (Table 1). Middle ear endoscopic findings In all subjects, the endoscopic approach allowed us to recognize the anatomical conformation of the tympanic cavity. Regarding the malformations of the middle ear, we observed an anomalous course of the facial nerve in 3/5 subjects; in
Fig. 5 (patient number 1) Preoperative CT scan in subject with malformed middle ear (subject affected by CHARGE syndrome). a Axial view. A sclerotic mastoid (black triangle) without antrum cell, the epitympanic space is present with an anomalous incudomalleolar joint. b Axial view. Anomalous course of the tympanic segment of the facial nerve (white triangle) covering the round
123
one of these cases where a CHARGE syndrome (patient number 1) was detected, an aberrant course of the facial nerve was found, the nerve was dehiscent and located under the stapes over the promontory, obscuring the round window niche. In patient number 3, the round window was hidden and surgically inaccessible, due to displacement of the facial nerve; an anomalous course of the tympanic segment of the facial nerve was found, in association with a hypoplastic oval window; in this case, the nerve was dehiscent, partially covering the oval window and running below the cochleariform process. Patient number 4 presented a dehiscent tympanic segment of the facial nerve. In 3/5 subjects, an anomalous conformation or anatomical position of the round window membrane and niche was found. In 2/3 subjects (patient number 2 and 4), the niche of the round window was situated in a more cranial position and a tegmen removal was necessary to detect the membrane. In 1/4 subjects (patient number 1), because of the presence of an anomalous course of the facial nerve, the round window was covered by the nerve running below the oval window and ossicles, across the promontory.
window. c From analysis of the CT scan in the coronal view, the facial nerve runs over the promontory (white triangle) and over the round window niche (white arrow). d Coronal view. The cochlear nerve was detected in an anomalous position; aplasia of the nerve is suspected (black arrow)
Eur Arch Otorhinolaryngol Fig. 6 (patient number 2) Preoperative CT scan of subject with malformed inner ear (incomplete partition type I). a, b Axial view. The mastoid is pneumatised and ossicles are present. A malformed inner ear is visible: Aplasia of the semicircular canals with hypoplastic aspect of the vestibule is detected. c, d Coronal view. The normal partition in the cochlear spiral is absent, so the cochlea appears only as a single cavity. Bilaterally it looks like an empty cystic space and in a lateral position with respect to the promontory
Regarding the ossicles, in 3/5 subjects, a normoarticulated ossicular chain was present; in 2/3 subjects, an anomalous ossicular chain was found. In the patient affected by CHARGE syndrome (patient number 1), the stapes was fused with the long process of the incus, and in patient number 3, a rudimental incus and malleus were found in association with a hypoplastic oval window. Surgical approach In all five subjects, we were able to perform endoscopic assisted surgery. Endoscopic approach Direct endoscopic control of anatomical structures such as the facial nerve, the round window niche, the promontory and ossicles was achieved in all subjects, allowing the cochleostomy to be performed using the endoscopic approach. In four subjects, an endoscopic cochleostomy was performed through the round window niche; in two subjects, the round window membrane was found to be in an anomalous position. In 3/4 subjects, the tegmen of the round window niche was regularized with a diamond burr, until the round window membrane was identified. In one of these cases, a double membrane on the niche of the round window was detected and removed.
In one subject, a round window membrane was exposed endoscopically, without any drilling procedure. As a result of facial nerve displacement on the round window, a promontorial cochleostomy was performed in 1/5 subjects (patient number 1); in this case, drilling of the promontory area was performed just anteriorly and inferiorly with the respect of the round window, entering into the scala tympani and avoiding damage to the facial nerve (Fig. 3c, d). No intraoperative gusher was found in any subject. Microscopic approach In 3/5 subjects, a suprameatal approach was used due the presence of a sclerotic mastoid. In 2/3 of these subjects, as a result of the epitympanic conformation, incus removal was necessary to obtain a direct connection between the suprameatal route and the mesotympanic spaces. In 2/5 subjects, where normal mastoid air cells were present in association with a normal course of the facial nerve, a posterior tympanotomy was performed. In all cases, the receiver–stimulator of the implant was fixed and covered under the temporalis muscle. In 5/5 subjects, array insertion was performed through the cochleostomy previously created, without any problems. Neural responses were tested confirming the correct insertion of the electrode. In all subjects, a small piece of temporalis fascia was used with fibrin glue to seal the
123
Eur Arch Otorhinolaryngol
cochleostomy. A radiologic intraoperative X-ray was performed in all cases to verify the correct insertion of the electrode. All patients underwent an intraoperative facial nerve monitoring (NIM). Complications No intraoperative complications were observed in this series. In all subjects, discharge from hospital was usually on the third day postoperatively. No postoperative complications were noted. At present, the mean follow-up time is 6 months (range 4–12 months) and no complications have been reported. Audiologic results All patients exhibited profound hearing loss at preoperative evaluation. All of the implanted children showed varying degrees of auditory benefit as measured by routine audiometry and speech perception tests.
Discussion Middle/inner ear malformations present technical problems for cochlear implant surgery, most notably an anomalous course of the facial nerve may be present in these patients, and cerebrospinal fluid (CSF) gusher may be expected [5, 6]. Iatrogenic damage to the facial nerve is still a major surgical complication after cochlear implantation and anatomical exposure of the round window through posterior tympanotomy could be a problem in patients with cochleo-vestibular malformations, such as in syndromic patients. Sennaroglu et al. [7] reported their surgical results for cochlear implantation in malformed cochlea. From this experience, the authors stated that, during cochlear implantations in malformed ears, the standard mastoidectomy with a facial recess approach could be adopted, but the surgical approach must be tailored according to anatomical findings in individual patients. The surgeon must be ready to modify the surgical approach during surgery and in cases with difficult anatomy, a canal wall down technique might be used to identify the anatomical landmarks avoiding injury to the facial nerve. Some authors have suggested a subtotal petrosectomy approach, to obtain a better view of the surgical field. Free et al. [8] suggested subtotal petrosectomy in middle ear malformations to help identify available landmarks, if possible. Furthermore, the risk of developing meningitis during their lifetime is higher in subjects with inner ear malformations than in the normal population, even without CI surgery. In their experience with subtotal petrosectomy, they reported two middle ear malformations treated with this technique for CI; one of
123
these two procedures was complicated by a subcutaneous collection of CSF, postoperatively treated with sterile puncture and head bandage for 7 days. In our opinion, subtotal petrosectomy could be a good choice when an intraoperative CSF leakage/gusher has occurred and surgical management has been difficult. In these specific cases, this approach could allow better control of the CSF leakage, through obliteration of the Eustachian tube orifice and cavity, but some risks, related to the surgical procedure should be considered. First of all, the possibility of fat infection could be very dangerous, if the possible consequent infection spreads through the cochleostomy and develops into meningitis. Then, there is the possibility of entrapped cholesteatoma in the obliterated cavity. For this reason, prolonged postoperative follow-up is required (only a CT scan can be planned, as there is no possibility of performing MRI) and a staged procedure may be performed. To prevent facial paralysis and injury to the chorda tympani, other authors [9–11] have developed an alternative technique in which the electrode of the cochlear implant is introduced into the middle ear via a suprameatal route, in contrast to classic mastoidectomy with the posterior tympanotomy approach. This suprameatal approach differs from the classic approach in avoiding a mastoidectomy, so the facial nerve is protected by the body of the incus when the middle ear is entered by drilling the suprameatal tunnel. In recent years, the endoscopic approach to the tympanic cavity has improved, giving better knowledge of the anatomical structures and permitting a minimally invasive approach for selective diseases located in the tympanic cavity such as attic cholesteatoma [12–14]. When an unfavorable anatomical condition was detected during radiologic exam in the preoperative period in subjects who were candidates for cochlear implants, we started to use the endoscopic approach to magnify and identify the anatomy of the tympanic cavity. This series represents the first experience with endoscopic assisted surgery for malformed ears. In our series, we adopted a transcanalar approach to reach the tympanic cavity and to recognize the tympanic cavity endoscopically and we performed the cochleostomy under endoscopic control. The second part of the surgery was performed under microscopic view, creating a suprameatal or transmastoid facial recess route to reach the tympanic cavity, based on the characteristics of the mastoid on CT scan. Since the main issue in cochlear implants in malformed ears is correct exposure of the anatomical structures to obtain anatomical landmarks thus avoiding facial nerve injury and performing a correct cochleostomy for array insertion, we started to use the endoscopic approach routinely. The advantages of this technique can be so highlighted. First of all, endoscopic procedure helps the surgeon to recognize the anomalous anatomy of the tympanic cavity and the surrounding
Eur Arch Otorhinolaryngol
Fig. 7 (patient number 2) Transcanal endoscopic approach. Right ear. a After tympanomeatal flap elevation, the round window niche and membrane were endoscopically detected; b A diamond burr was used under endoscopic view to enlarge the niche of the round window, uncovering the round window membrane. c Endoscopic view of the round window membrane; the membrane was located
cranially in an anomalous position, close to the oval window and stapes. d Microscopic step. A transmastoid approach was performed maintaining the integrity of the external auditory canal; array insertion was carried out through the mastoid route into the cochleostomy previously created. rw round window, ma malleus, s stapes, in incus, ct chorda tympani
anatomical structures, thus performing a safe cochleostomy, especially in case of an abnomalous facial nerve course. The possibility of ‘‘looking around the corner’’ and the magnification of the structures using the endoscopic approach permit to explore the tympanic cavity and to check all anatomical features. The endoscopic step also permitted the transmastoid/suprameatal microscopic step to be performed more safely even in subjects with unfavorable conditions such as a sclerotic mastoid, by knowing the exact location of the anatomical structures going into the tympanic cavity such as the course of the facial nerve. Finally, it’s possible to preserve the integrity of the posterior canal wall and to have a direct exposure of the tympanic cavity anatomy (Fig. 7a–d), avoiding subtotal petrosectomy or an open approach as some authors have suggested for the treatment of malformed ears. No minor or major complications were observed in our series. Regard to audiologic results, owing to the unpredictable distribution of neural tissue in inner ear anomalies, the final outcome after implantation is not predictable in these patients. For these reasons, despite the challenging surgical approach adopted to position the electrodes correctly, the audiologic results could be lower than expected and not comparable
with respect to subjects with a normal anatomy, so the development of a surgical technique with low morbidity and with a minimally invasive approach should be considered in these subjects.
Conclusion From this preliminary report, endoscopic support is recommended especially when difficult anatomy is expected in candidates for cochlear implantation. Where the anatomical conditions are unfavorable for traditional transmastoid, facial recess surgery, such as in CHARGE syndrome or other conditions of ear abnormalities, an endoscopic transcanalar approach to the round window niche should be attempted. In contrast to the traditional microscopic approach, it allows better identification of promontorial structures, in particular, in malformed ears. This technique may also have applications within the field of cochlear and facial malformation, where traditional techniques and also neuroradiological investigations do not always provide satisfactory answers to the needs of the patient and the otosurgeon. Owing to the small number of
123
Eur Arch Otorhinolaryngol
subjects, further studies will also be necessary and each new technique introduced into surgery, possibly representing an advance in the ongoing process of development of scientific knowledge, always requires long-term validation and lengthy follow-up, designed to test possible criticality and confirm the results. Acknowledgments These cases were derived from the Otolaryngology Department, University Hospital of Modena. Conflict of interest All of the authors have read and approved the manuscript. None of them have any financial relationships to disclose.
References 1. Jackler RK, Luxford WM, House WF (1987) Congenital malformations of the inner ear: a classification based on embryogenesis. Laryngoscope 97:2–14 2. McClay JE, Tandy R, Grundfast K et al (2002) Major and minor temporal bone abnormalities in children with and without congenital sensorineural hearing loss. Arch Otolaryngol Head Neck Surg 128:664–671 3. Sennaroglu L, Saatci I (2002) A new classification for cochleovestibular malformations. Laryngoscope 112:2230–2241 4. Mylanus EAM, Rotteveel LJC, Leeuw RL (2004) Congenital malformation of the inner ear and pediatric cochlear implantation. Otol Neurotol 25:308–317 5. Hoffman RA, Downey LL, Waltzman SB, Cohen NL (1997) Cochlear implantation in children with cochlear malformations. Am J Otol 18:184–187
123
6. Graham JM, Phelps PD, Michaels L (2000) Congenital malformations of the ear and cochlear implantation in children: review and temporal bone report of common cavity. J Laryngol Otol Suppl 25:1–14 7. Sennaroglu L, Sarac S, Ergin T (2006) Surgical results of cochlear implantation in malformed cochlea. Otol Neurotol 27:615–623 8. Free R, Falcioni M, Di Trapani G, Giannuzzi A, Russo A, Sanna M (2013) The role of subtotal petrosectomy in cochlear implant surgery—a report of 32 cases and review on indications. Otol Neurotol 34:1033–1040 9. Kronenberg J, Migirov L, Dagan T (2001) Suprameatal approach: new surgical approach for cochlear implantation. J Laryngol Otol 115:283–285 10. Kronenberg J, Migirov L, Baumgartner WD (2004) The suprameatal approach in cochlear implant surgery: an alternative surgical approach to cochlear implantation. Otol Neurotol 25:41–44 11. Postelmans J, Van Spronsen E, Grolman W et al (2011) An evaluation of preservation of residual hearing using the suprameatal approach for cochlear implantation: can this implantation technique be used for preservation of residual hearing? Laryngoscope 121:1794–1799 12. Marchioni D, Alicandri-Ciufelli M, Piccinini A, Genovese E, Presutti L (2010) Inferior retrotympanum revisited: an endoscopic anatomic study. Laryngoscope 120(9):1880–1886 13. Marchioni D, Villari D, Mattioli F, Alicandri-Ciufelli M, Piccinini A, Presutti L (2013) Endoscopic management of attic cholesteatoma: a single-institution experience. Otolaryngol Clin North Am 46(2):201–209 14. Marchioni D, Grammatica A, Alicandri-Ciufelli M, Genovese E, Presutti L (2014) Endoscopic cochlear implant procedure. Eur Arch Otorhinolaryngol 271:959–966
