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Otology & Neurotology 39:45–53 ß 2017, Otology & Neurotology, Inc.

Cochlear Implantation in Chronic Otitis Media With Cholesteatoma and Open Cavities: Long-term Surgical Outcomes Ashish Vashishth, Andrea Fulcheri, Sampath Chandra Prasad, Manjunath Dandinarasaiah, Antonio Caruso, and Mario Sanna Department of Otology and Skull Base Surgery, Gruppo Otologico, Piacenza, Rome, Italy

Objectives: To evaluate the long-term surgical outcomes of cochlear implantation (CI) in chronic otitis media (COM) with cholesteatoma and open cavities using subtotal petrosectomy (STP). To review device explantation (DE) patients and reimplantation considerations. Study Design: Retrospective review. Setting: Otology and skull base center. Patients and Methods: Charts of 35 patients (36 ears) with COM with cholesteatoma, including open cavities, who underwent CI were reviewed for surgical outcomes and DE. Patient demographics, pathologies, previous surgeries, staging of implantation, salient intraoperative findings at the time of implantation and follow-up were evaluated. Details of patients with DE were evaluated for cause, operative findings, and reimplantation considerations. Results: Mean age of patients was 65.94 years. Nineteen open cavities, 11 primary cholesteatomas, 3 petrous bone cholesteatomas, and 3 atelectatic middle ears represented the pathologies with 31 patients of CI with concurrent STP and

5 patients where implantation was staged. The mean followup was 7.16 years ranging from 2 to 13 years. Four patients (11%) had DE due to extrusion and cavity infection with three reimplanted in same or contralateral ear. All explantations occurred within 24 months of primary implantation. No residual or recurrent cholesteatoma was observed in any of the patients during follow-up. Conclusion: CI is feasible in COM with cholesteatoma and open cavities with the use of STP and single-stage implantation can be performed in the absence of purulence. Despite low risk of residual cholesteatoma post meticulous disease removal, risk of DE remains, particularly in open cavity patients, and is higher than standard implantation. Reimplantation is often possible with careful considerations. Key Words: Cholesteatoma—Chronic otitis media (COM)— Cochlear implantation (CI)—Open mastoid cavity—Subtotal petrosectomy (STP).

The rationale of obtaining an aseptic and stable field with adequate and lasting soft tissue cover is fundamental to favorable long-term outcomes in implantable auditory devices, particularly cochlear implantation (CI). Though normal implantation techniques have proven to be time tested in obtaining the above goals in the majority of patients, chronic otitis media (COM), particularly the squamous variant involving squamous epithelium in middle ear cleft, by its destructive, infective, and inflammatory properties, presents as a major disruption in achieving both asepsis and stability. Once considered a contraindication to CI (1), COM, particularly the squamous variant (SCOM), though ceases to be so, is accompanied albeit with significant alteration in surgical considerations and

highly variable outcomes, with possibility of complications, including device explantation (DE). Fisch and Mattox (2) in 1988 described the procedure of subtotal petrosectomy (STP) to isolate the middle ear cleft from external environment and nasopharynx by removal of mastoid cells, mucosa, epithelium, and closure of the external auditory canal (EAC) in a blind sac fashion with plugging of Eustachian tube (ET). Though initially described for the management of temporal bone tumors and skull base pathologies, it was applied to CI as well (3). The successful use of STP in refractory patients of SCOM, including radical draining or nonhealing cavities in pleuri-operated patients (4), seemed the logical prelude to its implementation in CI in SCOM and radical cavities (5–12). A few authors have suggested alternative soft tissue coverage techniques in open cavities (13) and canal wall reconstruction with or without staging of implantation (14). Despite these encouraging results, most studies report outcomes of COM in general with lack of raw data on exact nature and severity of pathology, coupled with relative paucity of patients with cholesteatomas or open cavities in the series.

Otol Neurotol 39:45–53, 2018.

Address correspondence and reprint requests to Ashish Vashishth, M.S., D.N.B., Department of Otology and Skull Base Surgery, Gruppo Otologico, Piacenza, Rome, Italy, 29121; E-mail: drashishvashishth@ gmail.com All authors take responsibility of the contents of the article. The present study was funded by The Mario Sanna Onlus Foundation. The authors disclose no conflicts of interest. DOI: 10.1097/MAO.0000000000001624

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Copyright © 2017 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.

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The current study was undertaken to review the cases of SCOM, including open cavities, that underwent CI, and to analyze the complications during long-term follow-up. METHODS Medical records were analyzed to identify patients with COM-related pathology who underwent CI with at least a 2year follow-up period postimplantation. Sixty-two patients were identified who underwent a CI with COM-related pathologies satisfying the above criteria. Patients with mucosal COM or recurrent otitis including tympanic membrane perforations, whether managed using STP or not, were excluded. Thirty-nine patients were identified with the above criteria with STP as the chief intervention for CI. One patient has since deceased due to unrelated causes and was hence excluded. One patient with surgery postradiation therapy for nasopharyngeal malignancy was excluded. Two patients had primary implantation done at another center and were referred for the management of array misplacement into petrous carotid and cavity infection respectively, and were also excluded. This yielded a study cohort of 35 patients (36 ears) who received a CI with STP with or without staging of the procedure. Figure 1 demonstrates the patient

inclusion flowchart from the pool of COM patients. The pathologies included in SCOM were radical/open cavities, cholesteatomas, retraction pockets, adhesive COM/middle ear atelectasis, and petrous bone cholesteatomas (PBC). Patient charts were evaluated for demographics, primary pathology, mention of previous surgeries, salient intraoperative findings at the time of implantation, duration of follow-up, and interval between primary STP and implantation where the same was staged. Our philosophy in SCOM is essentially of single-stage STP with CI in the absence of purulence. No canal wall reconstruction or open cavity retention has been performed for implantation in SCOM patients. Though our technique of STP in SCOM (4) and with relevance to CI has been described before (15–17), few salient features that need to be mentioned are the double-layered closure of EAC blind sac, ET obliteration with periosteum, cartilage and bone wax postmucosal coagulation, and cavity obliteration using abdominal fat graft. No temporalis or posteriorly based musculoperiosteal flap was used for obliteration. Abdominal fat graft is harvested shortly before the completion of bone work and is soaked in antibiotic solution containing Rifampicin till the point of placement in STP cavity. Standard antibiotic prophylaxis consisted of Piperacillin given intravenous from the time of induction to 3 days

FIG. 1. Flowchart elaborating patient inclusion (squamous COM) from pool of chronic otitis media (COM) and associated pathologies.

Otology & Neurotology, Vol. 39, No. 1, 2018


CI IN CHOLESTEATOMA AND OPEN CAVITIES postoperatively. Patients are routinely discharged on fourth postoperative day and continue the same antibiotic through intramuscular route for 6 more days till a total of 10 days postoperatively. Ceftriaxone is used as the alternative antibiotic in case of intolerance to Piperacillin. Some of the patients in the current study have been reported elsewhere previously (16,17). The general time of waiting before implant placement after STP is less than 6 months, based on observations during primary surgery, followed by imaging before definitive implantation. Receiver-stimulator (R/S) bed was drilled in all patients with sutures used for fixation of the same, except in patients of Oticon implants where R/S was fixed using screws to avoid migration. Preoperative high resolution computed tomography of the temporal bones and magnetic resonance imaging were done in all patients for disease evaluation and assessment of cochlear luminal patency. Routine postoperative radiological follow-up protocol at our institution is of computed tomography (CT) scan at yearly follow-up for the 1st 3 years and once in 2 years for the subsequent years, encompassing a cumulative 10-year follow-up. A note was made of postoperative complications. DE were evaluated for reasons and circumstances of re-exploration, operative findings, along with the temporal time pattern of the same and reimplantations, wherever performed. Fifteen Oticon (Neurelec/MXM), 14 Medel, and 7 Cochlear devices were used in the study group.

RESULTS The mean age of patients was 65.94 years with 25 males and 11 females. One patient had bilateral sequential implantation. The maximum age at implantation was 86 years with minimum being 17 years. Table 1 shows the demographics, surgical observations at the time of implantation, pathology, and follow-up periods of patients with no evidence of DE till date. Table 2 displays the patients who underwent DE with or without reimplantation with details on time to explantation and reasons for the same. Out of 36 ears, 31 were single-stage implantations with STP. Five ears were staged with the time between STP and implantation ranging from 2 months to 3 years. The longer periods ranging years between two procedures were due to the primary STP being performed for the management of SCOM/open cavity without any contemplation of CI. The decision to place an implant was taken later postsignificant deterioration in hearing. In none of the patients postprimary STP for staging was a primary CI deferred due to evidence of infection/cholesteatoma recurrence. All the patients who had DE had single-stage implantations, three with open cavities and one with cholesteatoma. The distribution of pathologies in single-stage implantation was: 1. Cholesteatomas: 11 (including three supralabyrinthine PBCs) 2. Radical/open cavities: 17 3. Atelectatic middle ears: 3 In staged procedures, primary STP was performed for cholesteatoma in three cases and open cavity in two instances respectively.

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In all the open mastoid cavities operated for STP with CI, three patients had residual cholesteatoma at the time of STP. Two of these underwent CI in the same setting postcomplete removal of cholesteatoma whereas one underwent staging of implantation due to the presence of extensive granulations. In addition, one patient of PBC had more than one open mastoidectomies before with incomplete cholesteatoma removal. Three patients with previous open cavity mastoidectomies despite not having any ‘‘residual cholesteatoma’’ had epithelium attached to exposed middle and posterior cranial fossa dura. In all the instances, disease removal at the time of STP was complete followed by CI in the same setting. The mean follow-up was 7.16 years ranging from 2 to 13 years. At the time of writing the current manuscript, no other patient in the above said category with primary implantation performed at our institution had any DE, even in cases with follow-up less than 2 years. Out of four DEs, three patients have been reimplanted with two in the same ear and one in the contralateral ear (using singlestage STP with CI). One patient remains to be implanted postevidence of granuloma formation in exploratory surgery 2 years following DE (Table 2, Patient 4). No other complications were observed in any patients. Two patients (Table 1, Patients 6 and 26) had preoperative facial paresis from previous surgeries or disease process itself. One patient (Table 1, patient 17) had complete basal turn scala tympani ossification necessitating scala vestibuli insertion. All patients of supralabyrinthine PBCs were managed using STP with translabyrinthine approach and CI (Table 1). Figure 2A and B shows preand postoperative CT images from a patient with PBC post-translabyrinthine approach and CI. Six patients had gross middle fossa dural exposure/meningo-encephalic herniation with adhered epithelium. No cholesteatoma recurrence was noted in any patient as observed on follow-up CT scans. All extrusions occurred trough postaural region with no breakdown of EAC closure. The minimum time between primary implantation and DE was 4 months with maximum being 24 months. Among the explanted devices, two each were present from Medel and Oticon. DISCUSSION Table 3 describes a brief review of literature highlighting selective publications on subset of patients with CI in COM with representation of pathologies, surgical techniques, follow-up, prospect of staging, and complications including DE. When confronted with a patient with SCOM or open cavity situation, pertinent questions regarding CI are the decision to perform obliteration of middle ear cleft or not and of staging the procedure. While there has been a growing consensus on the use of STP/middle ear obliteration in implantation in SCOM (6,8,9–12), few authors have used alternative methods such as canal wall reconstruction (14) and use of pericranial flaps with retention Otology & Neurotology, Vol. 39, No. 1, 2018


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TABLE 1. Demographic features, pathology, staging, previous surgeries, and salient operative findings at the time of implantation in patients not having any device explantation

S. No

Age/Sex

Pathology

No. of Previous Surgeries

Staging

Duration Between STP and Implantation If Staged

Side

1

82/F

PSRP with cholesteatoma

0

SS

N/A

Rt

2

68/M

Epitympanic cholesteatoma

0

SS

N/A

Lt

3 4 5

67/M 52/M 72/M

Radical cavity Post STP for cholesteatoma Cholesteatoma with LSSC fistula

1 3 2

SS Staged SS

N/A 5 months N/A

Lt Lt Rt

6 7

67/M 74/F

Radical cavity Radical cavity

4 1

SS SS

N/A N/A

Lt Rt

8 9

46/M 50/F

2 4

SS Staged

N/A 3 years

Lt Lt

10 11 12

73/F 65/M 79/M

Radical cavity STP for multiple open cavity surgeries Radical cavity PSRP with cholesteatoma Radical cavity

1 1 2

SS SS SS

N/A N/A N/A

Rt Lt Lt

13 14 15 16

64/M 66/F 78/M 56/F

Radical cavity Post STP for cholesteatoma Adhesive OM Cholesteatoma

1 2 1 1

SS Staged SS SS

N/A 2 years N/A N/A

Lt Rt Lt Lt

17

60/M

Atelectatic OM with TS

0

SS

N/A

Rt

18

77/M

2

Staged

8 months

Rt

19 20 21 22

72/M 71/M 73/M 73/M

Post STP for infected radical cavity Radical cavity Epitympanic cholesteatoma Radical cavity Supralabyrinthine PBC

2 0 1 0

SS SS SS SS TLA

N/A N/A N/A N/A

Rt Rt Lt Rt

23

71/F

24

0

SS

N/A

Rt

79/F

TM perforation with middle ear epithelization Supralabyrinthine PBC

0

SS TLA

N/A

Rt

25 26

65/F 78/F

Radical cavity Supralabyrinthine PBC

1 3

SS SS TLA

N/A N/A

Lt Rt

27

63/F

2

Staged

2 months

Lt

28 29

55/M 86/M

Post STP for cholesteatoma with ME hernia and LSSC fistula Cholesteatoma Radical cavity

0 1

SS SS

N/A N/A

Rt Rt

30 31 32

72/M 66/M 66/M

Radical cavity Radical cavity Radical cavity

1 1 1

SS SS SS

N/A N/A N/A

Lt Rt Lt

Salient Surgical Findings at the Time of Implantation Epithelium on stapes superstructure Epitympanic and mesotympanic epithelization, RW scarring with fibrous tissue. Hypotympanic and perilabyrinthine cells drilled RW TS N/A Epithelium inside ET and LSC, RW scarring and minor ossification Dehiscent facial nerve Dehiscent MCFD covered with epithelium RW TS N/A N/A N/A Epithelized MEH with RW scarring N/A RW scarring Drilling of hypotymapnic cells MEH with CSF leak and RW scarring Extensive mesotympanic and RW TS and ST ossification N/A

Follow-up in Years 6 2

13 12 13

12 13 11 8 2 7 7 4 7 11 9 10 6

N/A N/A N/A Exposed MCFD with epithelium, cholesteatoma invading LSSC and SSSC RW scarring

9 7 8 8

Cochlear invasion with cholesteatoma Polypoidal mucosa in cavity MCFD and PCFD covered with matrix, cholesteatoma at fundus of IAC N/A

2

N/A PCFD exposed and covered with epithelium with RW ossification N/A N/A N/A

3

8 3

4 4 4

8 10 4

IAC indicates internal auditory canal; LSSC, lateral semicircular canal; MCFD, middle cranial fossa dura; MEH, meningo-encephalic herniation; OM, otitis media; PBC, petrous bone cholesteatoma; PCFD, posterior cranial fossa dura; PSRP, posterior superior retraction pocket; RW, round-window; SS, single stage; SSSC, superior semicircular canal; ST, scala tympani; STP, subtotal petrosectomy; TLA, translabyrinthine approach; TS, tympanosclerosis.



67/M

17/M

63/M

2

3

4

Radical cavity

Cholesteatoma

Radical cavity

Radical cavity

2014

2013

2009

2010

Year of Implantation

N/A

N/A

20 months

12 months

Time to Re-exploration

N/A

N/A

Cavity infection and retroauricular retraction

R/S exposure (minimal)

Reason for Re-exploration

N/A

Cavity infection and extrusion

Musculoperiosteal occipital flap used for reinforcement and cavity adhesiolysis, no active infection observed N/A

R/S extrusion

Cavity infection with retroauricular fistula

Cavity infection

Reason for Explantation

Resuturing

Re-exploration for Cavity Inspection/Partial Extrusion

Purulence at fistula site. R/S removed, transected array left in cochlea Granulation and inflammatory tissue around the R/S, bed drilled. Array transected and left in cochlea.

Polypoidal inflamed tissue þþ, R/S and array removed R/S removed, transected array left in cochlea. Skin defect sutured using rotation flap

Findings at Explantation

All the patients underwent STP at the time of primary implantation. Patient no. 4 has not been reimplanted at the time of editing of this manuscript. R/S indicates receiver stimulator.

41/M

1

Age/Sex

Primary Pathology

TABLE 2. Details of patients undergoing explantation and reimplantation.

4 months

STP revised after 2 years of explantation. Presence of granuloma and inflammatory tissue noted, debridement done without fat and re-implantation.

11 months

Opposite side implanted after 1 week using STP

22 months

4 months

7 days

Interval Between Reimplantation 24 months

Time to Explantation From 1st Implantation

CI IN CHOLESTEATOMA AND OPEN CAVITIES 49



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FIG. 2. A, Supralabyrinthine petrous bone cholesteatoma with involvement of labyrinth, posterior cranial fossa dural plate, fallopian canal, middle fossa dural plate, and minor cochlear erosion. B, Same patient post single stage subtotal petrosectomy with translabyrinthine removal of cholesteatoma and cochlear implantation. The extent of bone removal and differential fat interface with tissues is visible.

of open cavity (13), though limited to few patients with variable follow-up and outcomes. The use of STP has been seen with favorable outcomes not just with CI but also with other auditory implantable devices such as active middle ear implants (18,19), and as a final management of recalcitrant chronic otitis with multiple previous surgeries as standalone procedure (4,20), or in the preparation of future implantable auditory devices (21). A recent systematic review and meta-analysis on surgical complications of CI in canal wall down mastoid cavities analyzed 42 articles encompassing 424 patients and proved a significantly fewer global complications rate in patients with EAC closure than maintaining a canal wall down cavity (22). They also found no significant differences between staging the procedure versus implantation and EAC overclosure in the same stage. Though they were unable to control for meatoplasty size in their analysis, in our opinion and shared by other authors (12), blind sac closure is possible in all cases with meatoplasty, though requiring more skin eversion and an eventual more lateral plane of closure. No pedicle flap closure or reinforcement was needed in any of the patients in the current study despite loss of meatal tissue due to previous surgeries. Most (31/36) patients in the current study were implanted in single-stage irrespective of canal wall down cavity or cholesteatoma, including three patients of PBCs that were implanted as single stage using translabyrinthine approach with STP. Similar opinion is shared by other authors (10,12) that single-stage surgery is feasible and preferable wherever disease clearance can be ensured in the absence of purulence. This carries relevance in reducing one more surgery for the patient including anesthesia concerns (more so in the elderly), repeated postaural incisions and the need to reharvest fat from the abdomen. Though disease clearance is relatively easy in patients of recurrent otitis or even in mucosal COM, it is always not so in SCOM patients. As Table 1 demonstrates, at the time of primary implantation, many patients in the

current series had adverse intraoperative findings such as the presence of epithelium on stapes and inside ET orifice, exposed middle, or posterior fossa dura with epithelium or meningo-encephalic herniation, tympanosclerosis, dehiscent facial nerve, round window scarring or ossification, labyrinthine/cochlear erosion, and CSF leak with cholesteatoma extending as far as the fundus of internal auditory canal in PBCs. Extensive drilling of cell tracts is crucial not only for creating bare bone for better adhesion of abdominal fat graft to the cavity walls, but also for the prevention of mucosal granulomas that can stem from residual buried inflamed mucosa harboring infection (12). Though no residual or recurrent cholesteatoma was observed in the present series, residual inflamed mucosa was possibly the reason for cavity infection and DE (Table 2, Patient 4) in one instance with mucosal granuloma observed on re-exploration postexplantation, thus preventing reimplantation till the time being. Variations of Middle Ear Exclusion/Obliteration Various authors use partial middle ear exclusion techniques such as blind sac closure of EAC leaving intact the pneumatized mastoid (23), EAC closure without ET or fat obliteration (5), possibly for the identification of recurrent cholesteatoma. The prospect of not obliterating a cavity with EAC closure to gain pneumatized space for the identification of cholesteatoma on CT scan does not hold true as in time, all cavities get partially obliterated with soft tissue or fibrosis rendering any imaging nonusable. On the other hand, fat in the cavity provides a good interface to differentiate from cholesteatoma on CT scanning. Linthicum published the long-term histopathological fate of mastoid obliteration tissues and concluded that fat retained its volume and consistency over years despite slightly increased fibrous septations, whereas muscle lost volume but retained as a hyaline cover over mastoid bone and could promote healing (24). In our own set of patients, no abnormal soft tissue density



30 patients

39 patients

Bernardeschi et al., 2015

Baranano et al., 2013

8 RMCs, 2 active COMs including 3 cholesteatomas Cholesteatomas (11), PBCs (3), RMCs (19), Adhesive OMs (3)

7 RMCs and 3 cholesteatomas

COM (17) patients including 5 cholesteatomas, 2 RMCs, 2 adhesive OMs and 8 COMs

RMCs (9), COMs with or without cholesteatoma (6) 24 COMs with 3 cholesteatomas

Active/inactive COM with/without cholesteatoma (7) All RMCs

4 Adhesive OMs and 5 RMCs

4 RMCs, 1 cholesteatoma, 4 COMs

4 Adhesive OMs, 2 RMCs, 1 eosinophilic OM

Pathologies Distribution

STP with or without rotation of temporalis muscle flap into cavity STP for open cavities, Combined approach tympanoplasty STP

STP with fat or musculoperiosteal flap obliteration CWDM with ET obliteration with EAC closure with fat obliteration STP

18 months–12 years, mean 7 years

Staged

Staged or single stage


Single stage or staged

Single stage or staged

Single stage


2 years- 13 years

8 months–10 years

3–58 months, mean 21 months

8–84 months

0.5–12.3 years, mean 5.8 years

Mean 38 months

Staged and single stage

Staged for active COMs, single stage for inactive RMCs Single stage

1 explantation in previously irradiated patient, 1 incidental cholesteatoma during reimplantation for device failure

18–48 months, mean 34 months

Single stage for transcanal implantation, staged

Transcanal implantation with ET obliteration, canal wall reconstruction with mastoid obliteration and single patients of STP RM with EAC closure and ICWM with implantation First stage RM with EAC closure without ET or cavity obliteration using fat RM with EAC closure, normal implantation for inactive COMs Meatal closure (5 patients) and anteriorly based postauricular pericranial flap in open cavity for implant protection (6 patients)

4 explantations including two for device exposure and two for infections. All but one patients reimplanted.

1 explantation in CI with tympanoplasty

3 explantations with one due to abscess, 1 electrode extrusion revised without explantation, 1 cavity emphysema and 1 EAC closure revision due to granulations None

1 device failure and 2 abdominal hematomas

2 recurrent cholesteatomas in meatal closure group, 2 device failures likely due to R/S placement too close to cavity edge leading to lack of fantail connection support and 1 extrusion managed using cartilage and fascia cover 1 blind sac fistula, revised without explantation

No major complications/ explantations

No explantations/extrusions

1 explantation post ICW procedure for perforation with granulations

Complications/Explantations

Follow-up

Staging

Surgical Interventions

CI indicates cochlear implant; COM, chronic otitis media; CWDM, canal wall down mastoidectomy; EAC, external auditory canal; ET, eustachian tube; ICWM, intact canal wall mastoidectomy; OM, otitis media; PBC, petrous bone cholesteatoma; RM, radical mastoidectomy; RMC, radical mastoid cavity/open mastoid cavity; SCOM, squamous chronic otitis media; STP, subtotal petrosectomy.

36 patients of SCOM

16 patients

Casserly et al., 2016

Current study

11 patients

Nieman et al., 2016

13 patients

19 patients

Wong et al., 2014

Postelmans et al., 2009

9 SCOM

Xenellis et al., 2008

19 patients with 10 SCOM

9 total. 5 SCOM

Yoo et al., 2014

Szymanski et al. 2016

7 total 6 SCOM

No. of Patients

Kojima et al. 2010

Studies

TABLE 3. Brief comparison of recent studies on cochlear implantation in chronic otitis media, with or without cholesteatoma or radical/open cavities

CI IN CHOLESTEATOMA AND OPEN CAVITIES 51



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interface was noted with respect to the fat in any of the patients during radiological follow-up. Nevertheless, despite the radiation exposure due to repeated CT scans, it is our view that radiological follow-up is required in these patients to evaluate possibility of residual cholesteatoma. Three of four patients undergoing DE had retraction and subsequent device exposure around the R/S and postaural region (Table 2). No other patients had any significant wound retraction or aesthetic concerns. The same could be attributable to the presence of fat in STP cavity. Obliteration of dead space in temporal bone and beyond using abdominal fat grafts is standard practice in the institution of study, including for tranlabyrinthine and other lateral skull base procedures. Though certain reduction in volume of fat is evident by the end of 1 year, rest of the fat retains its characteristics well over time, a feature observed even at the time of re-exploration many years after primary surgery. The STP cavity (with respect to CI) is much smaller than dead spaces created postinfratemporal fossa and translabyrinthine procedures, possibly explaining the lack of significant wound retraction in the current subset of patients. The presence of implantable devices in the same mileu, however, can potentially complicate wound retraction leading to DE, particularly in the presence of subclinical infection. Certain authors use musculoperiosteal (11) or temporalis muscle flaps (12) with or without fat grafts for cavity obliteration in STP in CI. Though they seem to reinforce the closure, at least in theory, no statistically significant difference was observed when use of fat alone, rotation of temporalis muscle over fat and use of alloplastic materials was compared in a large series of patients undergoing STP in the preparation for auditory implantation to compare their influence on wound healing and revision surgery (21).

presence of bacterial traces on the transected array removed during reimplantation, though dissimilar to the previous explanted R/S microflora and significantly lesser in terms of microbial burden. Nevertheless, such microbial traces may predispose for secondary infection in the reimplanted device and possible re-explantation, something observed in the above study (25). In one patient, implantation in the contralateral ear was feasible and the same was done using STP (presence of SCOM). Our higher incidence of implant extrusion (11.11%) in the current series as compared with Bernardeschi et al. (10) and others (Table 3) can be explained by the case selection in the current series, but goes on to proving that CI is certainly feasible in SCOM and in extensive disease if disease removal can be ensured. The risk of wound dehiscence is inherent to the pathology of SCOM and its surgical management using STP (4,20,21,26), as is to the procedure of CI as well over the R/S (27) and could be further compounded by extensive disease or multiple previous surgeries that create ischemia and fibrosis of postaural region due to compromised vascularity. Most patients in the current series had more than one previous surgery. Despite the patient selection, incidence of DE in this particular subset is significantly higher than standard implantation and implantation in SCOM. With most explantations (3/4) observed in patients with open cavities, it can be assumed that loss of vital soft tissue during open cavity mastoidectomies does pose a significant risk of DE, even among the subgroup of COM with squamous pathology. Though not use in the current series, the use of vascularized flaps such as temporoparietal fascial flap based on superficial temporal artery (20) seem a valid choice to manage at risk cases or for cavity reinforcement post-DE to augment wound healing.

Explantations The two most common complications of STP are postaural and blind sac fistula. Both in the context of CI can potentially lead to DE (Table 2). Though postaural fistula leading to exposure of R/S was the cause of explantation in two of four patients, evidence of infection in the form of frank purulence or unhealthy granulation tissue was observed in all the patients at the time of DE. When confronted with DE, the pertinent issues are reimplantation in the same or contralateral ear (should valid indications and prerequisites exist) and the time difference between explantation and reimplantation. Two patients were reimplanted in the same ear as indications to implant the other ear did not exist yet with one patient reimplanted as early as 7 days postexplantation due to the removal of the electrode array from cochlea because of the presence of granulation tissue around the cochleostomy site. Delaying reimplantation any further carried the potential to lose the cochlear lumen permanently due to fibrosis in previous tract sheath. Though it is a standard practice to cut the array during DE and leave the intracochlear portion in place to avoid fibrosis and loss of cochlear lumen, a recent study (25) did demonstrate the

Comparison to Noncholesteatomatous COM When reviewing explantations in patients of COM with mucosal disease (tympanic membrane perforations), explantations have been reported in the literature (6,7). While the presence of granulations despite previous intact canal wall mastoidectomy (7) and immunosuppression (9) has been observed in some reports, no apparent reason could be detected in others (6). Given the relatively small number of cases reported in most studies previously, no head-to-head comparisons could be drawn between cholesteatomatous and mucosal COM. In the current cohort of patients with COM and associated pathologies, none of the patients with mucosal COM had any cavity infection or DE. In our experience, CI in mucosal COM with tympanic membrane perforations is technically simpler and more predictable, whether performed using staged tympanoplasty or STP. The lack of adherent squamous epithelium or altered postaural and conchal soft tissue makes dissection in tissue planes simpler and wound closure more robust. However, the presence of active infection or unhealthy granulations must be sought for at the time of implantation to avoid cavity infection and DE.



CI IN CHOLESTEATOMA AND OPEN CAVITIES CONCLUSION CI is feasible in COM with cholesteatoma and open cavities with STP. Cases with extensive cholesteatoma or middle ear pathology and those with multiple previous surgeries, though technically challenging, can be implanted if disease removal is ensured using said protocols. Single-stage implantation is feasible in the absence of visible signs of infection, where the procedure can be staged. The risk of wound breakdown, device exposure, and cavity infection is certainly higher than normal implantation and can persist despite adequate disease control and the same must be communicated to the patients. Reimplantation in either ear is possible in most, if not all patients. REFERENCES 1. Belal A Jr. Contraindications to cochlear implantation. Am J Otol 1986;7:172–5. 2. Fisch U, Mattox D. Microsurgery of the Skull Base. Stuttgart, Germany: Georg Thieme Verlag; 1988. 3. Bendet E, Cerenko D, Linder TE, Fisch U. Cochlear implantation after subtotal petrosectomies. Eur Arch Otorhinolaryngol 1998;255:169–74. 4. Sanna M, Dispenza F, Flanagan S, De Stefano A, Falcioni M. Management of chronic otitis by middle ear obliteration with blind sac closure of the external auditory canal. Otol Neurotol 2007;29:19–22. 5. Xenellis J, Nicolopoulos TP, Marangoudakis P, Vlastarakos PV, Tsangaroulakis A, FerekIdis E. Cochlear implantation in atelectasis and chronic otitis media: Long-term follow-up. Otol Neurotol 2008;29:499–501. 6. Postelmans JT, Stokroos RJ, Linmans JJ, Kremer B. Cochlear implantation in patients with chronic otitis media: 7 years’ experience in Maastricht. Eur Arch Otorhinolaryngol 2009;266: 1159–65. 7. Yoo MH, Park HJ, Yoon TH. Management options for cochlear implantation in patients with chronic otitis media. Am J Otolaryngol 2014;35:703–7. 8. Wong MC, Shipp DB, Nedzelski JM, Chen JM, Lin VY. Cochlear implantation in patients with chronic suppurative otitis media. Otol Neurotol 2014;35:810–4. 9. Baranano CF, Kopelovich JC, Dunn CC, Gantz BJ, Hansen MR. Subtotal petrosectomy and mastoid obliteration in adult and pediatric cochlear implant recipients. Otol Neurotol 2013;34:1656–9. 10. Bernardeschi D, Nguyen Y, Smail M, et al. Middle ear and mastoid obliteration for cochlear implant in adults: Indications and anatomical results. Otol Neurotol 2015;36:604–9.

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11. Casserly P, Friedland PL, Atlas MD. The role of subtotal petrosectomy in cochlear implantation. J laryngol Otol 2016;130: S35–40. 12. Szymanski M, Ataide A, Linder T. The use of subtotal petrosectomy in cochlear implant candidates with chronic otitis media. Eur Arch Otorhinolaryngol 2016;273:363–70. 13. Nieman CL, Weinreich HM, Sharon JD, Chien WW, Francis HW. Use of pericranial flap coverage in cochlear implantation of the radical cavity: Rationale, technique and experience. Otolaryngol Head Neck Surg 2016;155:533–7. 14. Kojima H, Sakurai Y, Rikitake M, Tanaka Y, Kawano A, Moriyama H. Cochlear implantation in patients with chronic otitis media. Auris Nasus Larynx 2010;37:415–21. 15. Sanna M, Free R, Merkus P, et al. Surgery for Cochlear and Other Auditory Implants. Stuttgart: Georg Thieme Verlag; 2016. 16. Polo R, Del Mar Medina M, Aristegui M, et al. Subtotal petrosectomy for cochlear implantation: Lessons learnt after 110 cases. Ann Otol Rhinol Laryngol 2016;125:485–94. 17. Free RH, Falcioni M, Di Trapani G, Giannuzzi AL, Russo A, Sanna M. The role of subtotal petrosectomy in cochlear implant surgery— a report of 32 cases and review on indications. Otol Neurotol 2013;34:1033–40. 18. Verhaert N, Mojallal H, Schwab B. Indications and outcome for subtotal petrosectomy for middle ear implants. Eur Arch Otorhinolaryngol 2013;270:1243–8. 19. Henseler MA, Polanski JF, Schlegel C, Linder T. Active middle ear implants in patients undergoing subtotal petrosectomy: Long-term follow-up. Otol Neurotol 2014;35:437–41. 20. Yung M. The use of temporoparietal fascial flap to eliminate wound breakdown in subtotal petrosectomy for chronically discharging ears. Otol Neurotol 2016;37:248–51. 21. Lyutenski S, Schwab B, Lenarz T, Salcher R, Majdani O. Impact of surgical wound closure technique on the revision surgery rate after subtotal petrosectomy. Eur Arch Otorhinolaryngol 2016;273: 3641–6. 22. Hunter JB, O’Connell BP, Wanna GB. Systematic review and metaanalysis of surgical complications following cochlear implantation in canal wall down mastoid cavities. Otolaryngol Head Neck Surg 2016;155:555–63. 23. El-Kashlan HK, Arts HA, Telian SA. External auditory canal closure in cochlear implant surgery. Otol Neurotol 2003;24:404–8. 24. Linthicum FH Jr. The fate of mastoid obliteration tissue: A histopathological study. Laryngoscope 2002;112:1777–81. 25. Varadarajan VV, Dirain CO, Antonelli PJ. Microflora of retained intracochlear electrodes from infected cochlear implants. Otolaryngol Head Neck Surg 2017;157:85–91. 26. Vashishth A, Singh Nagar TR, Mandal S, Venkatachalam VP. Extensive intratemporal cholesteatomas: Presentation, complications and surgical outcomes. Eur Arch Otorhinolaryngol 2015;272: 289–95. 27. Gawecki W, Karlik M, Borucki L, Szyfter-Harris J, Wrobel M. Skin flap complications after cochlear implantations. Eur Arch Otorhinolaryngol 2016;273:4175–83.

