[Complications of cochlear implant surgery in children and adults]

Pneumatocoele after cochlear implantation with lateral petrosectomy: A minor complication?

OBJECTIVE

To illustrate the clinical features and management of pneumatocoele presenting with a trap-valve mechanism after cochlear implantation with lateral petrosectomy (LP) in comparison with literature.

INTRODUCTION

Pneumatocoele is a rare complication of cochlear implant (CI) surgery, generally managed with conservative treatments.

METHODS

We describe a progressively increasing pneumatocoele with a trap-valve mechanism occurring one year after CI with LP, successfully managed with revision surgery. Literature review was performed on this topic.

RESULTS

Our case was the second ever reported in literature. It appeared consequently to forceful nose-blowing in a patient with refractory nasal polyposis. Unlike the pneumatocoeles reported after standard CI, we advised revision surgery as well as in the case of pneumatocoele after staged LP and CI. In both the patients subcutaneous air collection occurred as a late complication and an insufficient Eustachian tube closure was disclosed, which is considered a complication of LP itself. Surgical management was necessary in consideration of the risk of ascending infections associated with Eustachian tube patency in LP with CI.

CONCLUSION

We consider surgical treatment mandatory in pneumatocoele after CI with LP, it is indeed the sentinel of the restoration of Eustachian tube patency and the potential prelude to major complications.

Acquired cholesteatoma after cochlear implants: case series and literature review

PURPOSE

To assess the prevalence and management of acquired cholesteatoma after cochlear implantation in pediatric and adult patients.

METHODS

Retrospective case review of pediatric and adult cochlear implants (CI) followed at a tertiary referral center and literature review of acquired cholesteatoma after CI surgery, to identify its prevalence, cause, and treatment.

RESULTS

Nine pediatric CIs were diagnosed with cholesteatoma in seven patients after 6.4 ± 4 years from CI surgery, and two adults after 11.3 and 21.7 years from CI surgery. Thirty-four pediatric cases and 26 adult cases are described in the literature. Cholesteatoma has a prevalence of 0.54% in pediatric CIs, and 1.79% in adult CIs (case series and literature). Adult cases were diagnosed significantly later compared to pediatric cases (Mann-Whitney test, p = 0.0460). Three pediatric cholesteatomas were treated with conservative surgery and preservation of the CI; they all developed recurrent disease. The remaining pediatric cases underwent subtotal petrosectomy with simultaneous CI explantation and staged reimplantation. Only one case recurred. The adult cases underwent simultaneous subtotal petrosectomy, explantation, and reimplantation. Similarly, 33.3% of cases treated with conservative/reconstructive surgery in the literature required revision surgery or conversion to subtotal petrosectomy against 6.2% of subtotal petrosectomies in the literature.

CONCLUSIONS

Cholesteatoma after CI is a rare and late-onset complication of CIs. It is more prevalent in the adult CI population, although it affects children significantly earlier. The treatment of choice is subtotal petrosectomy and CI explantation with simultaneous or staged reimplantation.

En route to sound coding strategies for optical cochlear implants

Hearing loss is the most common human sensory deficit. Severe-to-complete sensorineural hearing loss is often treated by electrical cochlear implants (eCIs) bypassing dysfunctional or lost hair cells by direct stimulation of the auditory nerve. The wide current spread from each intracochlear electrode array contact activates large sets of tonotopically organized neurons limiting spectral selectivity of sound coding. Despite many efforts, an increase in the number of independent eCI stimulation channels seems impossible to achieve. Light, which can be better confined in space than electric current may help optical cochlear implants (oCIs) to overcome eCI shortcomings. In this review, we present the current state of the optogenetic sound encoding. We highlight optical sound coding strategy development capitalizing on the optical stimulation that requires fine-grained, fast, and power-efficient real-time sound processing controlling dozens of microscale optical emitters as an emerging research area.

Intra-cochlear differences in the spread of excitation between biphasic and triphasic pulse stimulation in cochlear implants: A modeling and experimental study

Triphasic pulse stimulation can prevent unpleasant facial nerve stimulation in cochlear implant users. Using electromyographic measurements on facial nerve effector muscles, previous studies have shown that biphasic and triphasic pulse stimulations produce different input-output functions. However, little is known about the intracochlear effects of triphasic stimulation and how these may contribute to the amelioration of facial nerve stimulation. The present study used a computational model of implanted human cochleae to investigate the effect of pulse shape on the intracochlear spread of excitation. Biphasic and triphasic pulse stimulations were simulated from three different cochlear implant electrode contact positions. To validate the model results, experimental spread of excitation measurements were conducted with biphasic and triphasic pulse stimulation from three different electrode contact positions in 13 cochlear implant users. The model results depict differences between biphasic and triphasic pulse stimulations depending on the position of the stimulating electrode contact. While biphasic and triphasic pulse stimulations from a medial or basal electrode contact caused similar extents of neural excitation, differences between the pulse shapes were observed when the stimulating contact was located in the cochlear apex. In contrast, the experimental results showed no difference between the biphasic and triphasic initiated spread of excitation for any of the tested contact positions. The model was also used to study responses of neurons without peripheral processes to mimic the effect of neural degeneration. For all three contact positions, simulated degeneration shifted the neural responses towards the apex. Biphasic pulse stimulation showed a stronger response with neural degeneration compared to without degeneration, while triphasic pulse stimulation showed no difference. As previous measurements have demonstrated an ameliorative effect of triphasic pulse stimulation on facial nerve stimulation from medial electrode contact positions, the results imply that a complementary effect located at the facial nerve level must be responsible for reducing facial nerve stimulation.

[Emphysema after cochlear implantation - risk factors and therapeutic options]

OBJECTIVE

In case of cochlear implantation seroma, hematoma, local wound infections or vertigo are rare but typical complications. In contrast, emphysema is seldom reported. They can occur after cochlear implantation both in the postoperative healing phase and years later. A therapeutic algorithm does not yet exist.

METHODS

We report on 3 patients with subcutaneous emphysema in the area of the receiver-stimulator. An unsystematic review of the literature of cases with emphysema after cochlear implantation highlights possible risk factors and the therapeutic options.

RESULTS

The 3 cases developed subcutaneous emphysema 2-11 month after cochlear implantation due to nose blowing or CPAP therapy in obstructive sleep apnea. The current literature reports another 35 cases of emphysema after cochlear implantation. Air insufflation via the Eustachian tube is the most frequently described cause. Diseases of the nose and sinuses, tube dysfunction and obstructive sleep apnea are potential risk factors. Pressure bandage, puncture, tympanic tubes, and surgical revision are common treatments.

CONCLUSIONS

Most emphysema can be controlled by conservative methods such as pressure bandaging and behavioral instruction. Punctures should be avoided due to the risk of upcoming infections. The prophylactic use of antibiotics seems dispensable. Surgical revision should be considered especially in cases of pneumocephalus with suspected leakage in the dura. The coverage of the mastoidectomy by a bony cap can be precautious and beneficial in cases with risk factors.

A novel radiological method to evaluate the posterior tympanotomy depth for cochlear implantation: our experience in 257 patients

PURPOSE

This study aimed to validate our novel proposed radiological evaluation of the posterior tympanotomy (PT) depth. This dimension represents the bone of the facial recess needed to be drilled to get access into the middle ear during cochlear implantation.

METHODS

It was a retrospective observational study that included 257 patients who underwent cochlear implantation from July 2018 to April 2021 in tertiary referral institutions. Two physicians evaluated the preoperative HRCT to measure the PT depth in the oblique para-sagittal cut. On the other hand, two other physicians evaluated the unedited surgical videos to judge the PT depth and classified it into an ordinary PT or deep PT. Then, the preoperative radiological measurements were correlated with the intraoperative findings.

RESULTS

The radiological PT depth ranged from 2.5 to 5.4 mm with a mean of 3.91 ± 0.886. Sixty-six patients had ordinary PT, and 191 patients had deep PT. Spearman's correlation coefficient revealed a strong correlation between the preoperative radiological PT depth measurements and the intraoperative PT depth judgments (p value < 0.0001).

CONCLUSIONS

We created a novel radiological method to measure the posterior tympanotomy depth. This method was valid, reproducible, and reliable in the preoperative radiological evaluation of the PT depth with high sensitivity (91.71%), specificity (90.62%), and accuracy (91.44%). We also found a significant impact of the PT depth on the PT difficulty during cochlear implantation.

Apical Reference Stimulation: A Possible Solution to Facial Nerve Stimulation

OBJECTIVES

Postimplantation facial nerve stimulation is a common side-effect of intracochlear electrical stimulation. Facial nerve stimulation occurs when electric current intended to stimulate the auditory nerve, spread beyond the cochlea to excite the nearby facial nerve, causing involuntarily facial muscle contractions. Facial nerve stimulation can often be resolved through adjustments in speech processor fitting but, in some instances, these measures exhibit limited benefit or may have a detrimental effect on speech perception. In this study, apical reference stimulation mode was investigated as a potential intervention to facial nerve stimulation. Apical reference stimulation is a bipolar stimulation strategy in which the most apical electrode is used as the reference electrode for stimulation on all the other intracochlear electrodes.

DESIGN

A person-specific model of the human cochlea, facial nerve and electrode array, coupled with a neural model, was used to predict excitation of auditory and facial nerve fibers. These predictions were used to evaluate the effectiveness in reducing facial nerve stimulation using apical reference stimulation. Predictions were confirmed in psychoacoustic tests by determining auditory comfort and threshold levels for the apical reference stimulation mode while capturing electromyography data in two participants.

RESULTS

Models predicted a favorable outcome for apical reference stimulation, as facial nerve fiber thresholds were higher and auditory thresholds were lower, in direct comparison to conventional monopolar stimulation. Psychophysical tests also illustrated decreased auditory thresholds and increased dynamic range during apical reference stimulation. Furthermore, apical reference stimulation resulted in lower electromyography energy levels, compared to conventional monopolar stimulation, which suggests a reduction in facial nerve stimulation. Subjective feedback corroborated that apical reference stimulation alleviated facial nerve stimulation.

CONCLUSION

Apical reference stimulation may be a viable strategy to alleviate facial nerve stimulation considering the improvements in dynamic range and auditory thresholds, complemented with a reduction in facial nerve stimulation symptoms.

[The Impact of Subtotal Petrosectomy in Cochlea Implantation]

INTRODUCTION

Cochlear Implantation (CI) in patients with chronic otitis media or existing open mastoid cavity can be challenging. Subtotal petrosectomy (STP) is an option to improve the safety of this procedure.

MATERIAL AND METHODS

Retrospective study with cases of STP prior CI.

RESULTS

25 patients could be enrolled in this investigation. Over all 26 STP were performed approximately 6 months before CI. The majority of the patients suffered from a chronic otitis media or had a preexisting open cavity; in one case a complex temporal bone fracture with destruction of the external auditory canal was the reason for this technique. After STP we observed three times a delayed wound healing at the closure of the external auditory meatus and a bleeding at the periumbilical region after harvesting fat of the abdominal wall. All patients could be provided with a CI. A recurrence of a cholesteatoma did not appear so far.

CONCLUSION

With this method CI is feasible even in cases of concurrent chronic otitis media or canal wall down situation. We are in favour of a staged procedure, nevertheless a simultaneous STP and CI is justifiable in individual patients.

Cochlear Pathomorphogenesis of Incomplete Partition Type II in Slc26a4-Null Mice

Incomplete partition type II (IP-II) is frequently identified in ears with SLC26A4 mutations. Cochleae with IP-II are generally observed to have 1½ turns; the basal turns are normally formed, and the apical turn is dilated or cystic. The objective of this study was to characterize the pathomorphogenesis of the IP-II cochlear anomaly in Slc26a4-null mice. Otic capsules were dissected from Slc26a4^Δ/+ and Slc26a4^Δ/Δ mice at 1 and 8 days of age and at 1 and 3 months of age. X-ray micro-computed tomography was used to image samples. We used a multiplanar view and three-dimensional reconstructed models to calculate the cochlear duct length, cochlear turn rotation angle, and modiolus tilt angle. The number of inner hair cells was counted, and the length of the cochlear duct was measured in a whole-mount preparation of the membranous labyrinth. X-ray micro-computed tomography mid-modiolar planar views demonstrated cystic apical turns in Slc26a4^Δ/Δ mice resulting from the loss or deossification of the interscalar septum, which morphologically resembles IP-II in humans. Planes vertical to the modiolus showed a similar mean rotation angle between Slc26a4^Δ/+ and Slc26a4^Δ/Δ mice. In contrast, the mean cochlear duct length and mean number of inner hair cells in Slc26a4^Δ/Δ mice were significantly smaller than in Slc26a4^Δ/+ mice. In addition, there were significant differences in the mean tilt angle and mean width of the modiolus. Our analysis of Slc26a4-null mice suggests that IP-II in humans reflects loss or deossification of the interscalar septum but not a decreased number of cochlear turns.

Pre- and post-operative imaging of cochlear implants: a pictorial review

Cochlear implants are increasingly used to treat sensorineural hearing disorders in both children and adults. Pre-operative computed tomography and magnetic resonance imaging play a pivotal role in patient selection, to rule out findings that preclude surgery or identify conditions which may have an impact on the surgical procedure. The post-operative position of the electrode array within the cochlea can be reliably identified using cone-beam computed tomography. Recognition of scalar dislocation, cochlear dislocation, electrode fold, and malposition of the electrode array may have important consequences for the patient such as revision surgery or adapted fitting.

Comparison of the Surgical Techniques and Robotic Techniques for Cochlear Implantation in Terms of the Trajectories Toward the Inner Ear

OBJECTIVES

The ideal outcome of cochlear implant surgery involves the insertion of the array inside the scala tympani of the cochlea with the least mechanical trauma. Recently, round window insertion and the direction in which the cochlea is approached have gained attention in this respect. The Angles of Cochlear Approach (ACA) can be defined with a plane in the plane of the basal turn, termed the in-plane angle, and the plane orthogonal to this plane, termed the out-plane angle. The aim of this study was to compare the trajectory angles for different surgical techniques of Veria, suprameatal, pericanal, and multiple posterior tympanotomy (PT) approaches, including an optimal trajectory that is simulated for robotic surgery.

MATERIALS AND METHODS

The trajectories of these surgical techniques were simulated on the same high-resolution computed tomography scan. The simulated trajectory angles were analyzed with dedicated software for medical images, defining the ACA and distances to critical otological structures.

RESULTS

The ACA are the smallest for surgical techniques that pass thought the PT. However, performing a surgical PT can include variability in the ACA, ranging from almost 0° to 20.8° in an out-plane angle, depending on how close a surgeon would approach the facial nerve. The Veria, Suprameatal approach (SMA), and peri-canal approaches have larger ACA and minimal distances to the ossicular chain and the ear canal. The maximum distance to the facial nerve and the widest out-plane angle is observe with a pericanal approach. The optimal PT approach refers to the trajectory without collisions and with the best possible ACA that can be planned.

CONCLUSION

Different surgical approaches yield important differences in the ACA. PT allows better ACA with maximum distances to the critical structures. However, the optimal PT trajectory simulated for robotic keyhole surgery is a further improvement on the trajectories through the facial recess.

CSF Gusher and Its Management in Cochlear Implant Patient with Enlarged Vestibular Aqueduct

Aim is to share our experience of CSF gusher and its management during cochlear implant surgery in patients with enlarged vestibular aqueduct. All cases underwent classic cochlear implant surgeries via Veria technique. It is a retrospective study done at Civil Hospital Ahmedabad from January 2013 to March 2018 with 415 patients. The study includes 39 children between age groups 2-8 years who have enlarged vestibular aqueduct. In all 39 patients with enlarged vestibular aqueduct during cochleostomy there was CSF gusher which was managed by the covering the cochleostomy site with temporalis fascia. There was no need for use of fibrin glue in any case. But it was kept in standby mode in case needed. And there was no post operative CSF otorrea in any patients. While preparing the patient for cochlear implant whenever you come across enlarged vestibular aqueduct via HRCT temporal bone and MRI of cochlea, be prepared for CSF gusher while doing the cochleostomy. Csf gusher is intra operative challenge rather than a bad prognostic determine for post operative audiologic out come. Keeping fibrin glue in stand by helps if major CSF leaks happens. Finally, we achieved a simple stepwise algorithm for the management of gusher during cochlear implantation.

Initial surgical and clinical experience with the Nucleus CI532 slim modiolar electrode in the UK

OBJECTIVE

The goal of this work is to describe the first experience in the UK with the slim pre-curved perimodiolar electrode Nucleus CI532 in a continuous series of patients in terms of surgical and clinical reliability and early performance outcomes.

METHOD

In this retrospective review we describe the complication rate (including electrode array tip fold-over), NRT thresholds, hearing preservation, power efficiency and CI performance outcomes in a continuous series of 40 cochlear implants CI532 performed between October 2016 and November 2017 in 17 adults and 13 children with severe to profound hearing loss.

RESULTS

Preliminary data from these groups reveals some low-frequency hearing preservation in the CI532 group although none of the patients were conventional hearing preservation candidates. NRT thresholds, power efficiency, and BKB sentences in quiet were measured at 3 and 6 months post activation. There were no significant differences in these results. The average BKB score in quiet increases from 22% pre-operatively to 58% at 3 months and 70% at 6 months. In addition, although hearing preservation was not an objective, low-frequency thresholds were preserved in 20% of cases at 3 and 6 months post-operatively. Complications were observed in 5 cases, one case with non-device related aerocoele and four related to the device array: two cases of tip roll over, one case of the electrode array being placed extra-cochlea, and one case with the electrode buckling into the middle ear. The last 2 cases were dealt with per-operatively.

DISCUSSION

Our preliminary results with the CI532 implant indicate that it may be reliably placed with standard surgical techniques but care is needed during the deployment of the electrode. Further initial data suggest that switch on and early electrophysiological measures are comparable to the existing CI 512 device. However whilst preliminary, our data suggest that it may be possible to use this electrode for hearing preservation. However, further studies are required to determine its definitive advantage over other electrode designs.

CONCLUSION

CI532 is a reliable device offering good initial results and could be an option for hearing preservation although further studies are required.

Meta-analysis of subjective complaints of vertigo and vestibular tests after cochlear implantation

OBJECTIVE

Postoperative vertigo is a common complaint after cochlear implantation, but published incidence rates differ vastly. The aim of the present study was to investigate both subjective complaints of vertigo before and after cochlear implantation and related vestibular diagnostic tests on cochlear implant candidates.

DATA SOURCES

We performed a systematic literature search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement in PubMed, Cochrane Register, and EMBASE.

REVIEW METHODS

We presented 116 eligible studies investigating subjective complaints of vertigo after cochlear implantation and/or related vestibular diagnostic tests. We conducted three meta-analyses of 46 eligible studies with matched pre- and postoperative data to calculate the odds ratio of new vertigo onset, as well as the impairment of vestibular receptors measured by nystagmography and cervical vestibular evoked myogenic potentials (cVEMP). Postoperative vertigo was calculated from 95 studies and further subdivided by mean age with pooled data.

RESULTS

We observed a significant increase in postoperative vertigo and significant impairment of nystagmography and cVEMP detection. Vertigo after cochlear implantation was reported in 9.3% of the patients with a continuous increase in patient age at surgery. In a subgroup of studies, new onset of vertigo was found in 17.4% of the patients. In addition, 7.2% of the patients had persisting vertigo complaints, whereas 11.6% described an altered vertigo quality and 7.7% had their preoperative complaints resolved. A comparison of round window approach and cochleostomy revealed significantly increased vertigo after cochleostomy. Both insertion methods showed similar effects in nystagmography and cVEMP testing.

CONCLUSION

Cochlear implantation has a significant impact on subjective vertigo and vestibular receptor function. This is affected by the patient's age at the time of surgery. The surgical technique (round window or cochleostomy) may influence the outcome, but this requires further investigation. Younger patients may compensate better following vestibular dysfunction. Perioperative testing is required to correlate vestibular impairment and subjective complaints. Laryngoscope, 2018 Laryngoscope, 128:2110-2123, 2018.

Surgical complications and their management in cochlear implantees less than 5 years of age: The KEMH Pune experience

OBJECTIVE

To evaluate the incidence of surgical complications of cochlear implantation and their management at K.E.M. hospital Pune.

METHODS

It was a retrospective and prospective observational study conducted from February 2006 to December 2015 in the paediatric age group of 12 months to 5 years (213 cases). The complications were divided into major and minor groups based on the classification proposed by Cohen and Hoffman.

RESULTS

The mean age of implantation was 3.03 years (ranged from 1 to 4.11 years). Sixteen patients had complications. The overall incidence of complications was 7.51% which comprised of major (2.34%) and minor (5.16%) complications. The commonest major complications were flap-related issues and the commonest minor complication was facial paresis.

DISCUSSION

The results of our study were compared with similar studies conducted in the past. All surgical complications were treated conservatively or surgically with success.

CONCLUSIONS

Cochlear implantation is the safe procedure in children between the age group of 12 months and less than 5 years.

Influence of insertion depth in cochlear implantation on vertigo symptoms and vestibular function

OBJECTIVES

The aim of the present study was to investigate the effect of the electrode insertion depth in vestibular function after cochlear implantation.

MATERIAL AND METHODS

In a retrospective observational study design, 41 adult patients who had undergone cochlear implantation between 2006 and 2012 at a tertiary referral university hospital were included. The postoperative performed radiograph images of the petrous bone were acquired according to the Stenvers method. These were analyzed to determine electrode insertion depth. Pre- and postoperative subjective vertigo symptoms were assessed by a questionnaire. The function of the horizontal semi-circular canal was evaluated by caloric irrigation and the function of the sacculus was tested by using cervical vestibular evoked myogenic potentials pre- and postoperatively.

RESULTS

The average electrode insertion depth was 464°. A certain variability of insertion depth existed among the different electrodes according to their designs. No statistical difference of the insertion depth was found between patients with or without vertigo. There was also no correlation between electrode insertion depth and alterations of the measurable vestibular function.

CONCLUSION

In our study the variability of insertion depth didn't have a significant influence on subjective vertigo, horizontal semi-circular canal function or saccular function. Plain radiography is a rapid, simple and cost-effective method to determine electrode insertion depth after implantation. However the scalar position of the electrode cannot be analyzed in plain radiography, so that an interscalar dislocation as a possible influence in vestibular function remains undetected.

Acute Mastoiditis in Children with Cochlear Implants

Objective

Acute mastoiditis is an uncommon but challenging condition when it occurs in children with cochlear implant. The literature is scarce as to the management of this condition with regards to explantation. The objective of the study is to determine the need for explantation in patients with cochlear implants who suffer from acute mastoiditis.

Data Sources

Online medical databases—PubMed, Ovid Medline, Ovid Medline in process, Embase, Cochrane Library, CINAHL, Biosis, Google Scholar, and Scopus.

Review Methods

A systematic review of all publications addressing the treatment of mastoiditis in cochlear implant children prior to November 2013 was conducted. Data were collected from online medical databases—PubMed, Ovid Medline, Ovid Medline in process, Embase, Cochrane Library, CINAHL, Biosis, Google Scholar, and Scopus. The review was performed in 3 phases; an initial screening review of abstracts was performed, followed by a detailed review of full articles based on inclusion and exclusion criteria, and lastly a final review to extract data from selected articles.

Results

Twelve articles were found eligible for this systematic review including a total of 43 patients. Subperiosteal abscess was present in 14.3%. All patients received intravenous antibiotics as an initial treatment, and if needed, surgical intervention was performed. Only 1 patient required explantation (2.3%).

Conclusion

Prompt, aggressive medical and if needed surgical therapy can help in saving the implant and result in a favorable outcome.

Cerebrospinal fluid gusher in cochlear implantation

OBJECTIVES

To share our experience of cerebrospinal fluid (CSF) gusher in cochlear implantation.

METHODS

Demographic, radiological, and surgical results of patients with CSF gusher in 523 consecutive cochlear implant recipients including children and adults as well as our management technique were evaluated and a review of the literature has been included.

RESULTS

Fifteen (2.87%) cases had CSF gusher. Two patients (13.3%) were adults with post-lingual hearing loss and the rest 12 (86.7%) were children with congenital hearing loss. Twelve patients (80%) had various types of inner ear malformation. Three patients (20%) had no predictable risk of CSF gusher from history or pre-operative imaging. In all patients, CSF gushers were controlled with our technique of packing the electrode entrance site with no additional measures.

CONCLUSION

CSF gusher may occur with post-lingual hearing loss and in children with apparently unremarkable imaging and history. Thus, surgeons should always be ready to manage it. Management of CSF gusher can be mainly performed during the initial surgery by precise tight packing of the electrode entrance site. Furthermore, non-surgical or surgical measures are rarely required to stop a persistent leak. Our results show that our management technique may be recommended as well.

Subcutaneous emphysema and pneumolabyrinth plus pneumocephalus as complications of middle ear implant and cochlear implant surgery

We conducted a retrospective case review at a tertiary academic medical center for the complications of pneumolabyrinth with pneumocephalus and subcutaneous emphysema after surgery for middle ear and cochlear implants. Charts of 76 cochlear implant and 2 middle ear implant patients from January 2001 through June 2009 were reviewed. We identified 1 cochlear implant recipient with pneumolabyrinth and pneumocephalus, and 1 middle ear implant recipient with subcutaneous emphysema. Surgical exploration was performed for the pneumolabyrinth with pneumocephalus; the subcutaneous emphysema was managed conservatively. The patient with the cochlear implant, who had had a ventriculoperitoneal shunt placed, experienced pneumolabyrinth with pneumocephalus 6 years after uneventful surgery. Middle ear exploration revealed no residual fibrous tissue seal at the cochleostomy. The middle ear and cochleostomy were obliterated with muscle, fat, and fibrin glue. The ventriculoperitoneal shunt was deactivated, with clinical and radiographic resolution. On postoperative day 5, the patient who had undergone the middle ear implant reported crepitance over the mastoid and implant device site after repeated Valsalva maneuvers. Computed tomography showed air surrounding the internal processor. A mastoid pressure dressing was applied and the subcutaneous emphysema resolved. These 2 cases support the importance of recognizing the clinical presentation of pneumolabyrinth with associated pneumocephalus, as well as subcutaneous emphysema. Securing the internal processor, adequately sealing the cochleostomy, and providing preoperative counseling regarding Valsalva maneuvers and the potential risk of cochlear implantation in the presence of a ventriculoperitoneal shunt may prevent adverse sequelae.

The role of subtotal petrosectomy in cochlear implant surgery--a report of 32 cases and review on indications

OBJECTIVE

To report and review 32 cases of subtotal petrosectomy (SP) in cochlear implant (CI) surgery and to define the indications and contraindications for this procedure.

STUDY DESIGN

Retrospective case review + case reports.

SETTING

Tertiary skull base center.

PATIENTS

Cochlear implant database: 32 subtotal petrosectomies in 31 patients.

INTERVENTIONS

Subtotal petrosectomy with blind sac closure of the external auditory canal, closure of Eustachian tube, and abdominal fat obliteration in combination with cochlear implantation.

RESULTS

Indications for SP in CI surgery were as follows: chronic otitis media (n = 4), previous radical cavity (n = 13), previous subtotal petrosectomy (n = 4), ossification of the cochlea (n = 5), malformation of the inner ear (n = 2), and temporal bone fracture (n = 4). One patient was simultaneously bilaterally implanted; 2 cases were revisions. All procedures were performed in 1 stage. In 2 cases, complications were encountered (6%), one of which lead to reoperation (3%). None of the patients was explanted.

CONCLUSION

Subtotal petrosectomy combined with cochlear implantation is a procedure required in specific situations and lowers the risk of repetitive ear infections, CSF leakage, and meningitis by closing off all connection with the external environment. Additionally, it gives excellent visibility and access in difficult anatomy or in drill-out procedures. The complication rate of 6% is comparable with normal cochlear implantation. Preservation of residual hearing can be considered the only absolute contraindication as an open external meatus is necessary for use of electroacoustic stimulation. Risks of the SP+CI procedure are infection of the abdominal fat, breakdown of the blind sac closure, and entrapped cholesteatoma. Follow-up with CT imaging is therefore mandatory.

Endocochlear inflammation in cochlear implant users: case report and literature review

OBJECTIVES

Cochlear implantation is a relatively safe procedure with a low complication rate. The overall rate of complications among cochlear implant patients ranges from 6% to 20%. Major complications are those that are life-threatening or require surgery, whereas minor complications are those that can be medically treated. Nonetheless, certain complications, even if highly rare, may require specific investigations and treatments. Among these rare complications are those with endocochlear involvement, such as cochleitis or labyrinthitis, with fibrosis or ossification that could lead to explantation. The aims of the present study were to report a particular case of post-operative cochleitis and to review the rate of complications after cochlear implantation, emphasising those conditions with proven endocochlear involvement.

METHODS

We refer to the case of an eight-year-old Italian boy affected by the sudden onset of headache, ipsilateral otalgia and facial paresis, who presented to our clinic for inexplicable worsening of the performance of his implant and his residual hearing, six years after surgery. A complete investigation including (clinical history, routine, autoimmune and serological blood tests, electrophysiological measurements from the cochlear implant and neuroimaging) was performed and is herein described. Additionally, a comprehensive review of the literature was conducted using internet search engines; 274 papers were selected, 88 of which were best suited to our purposes.

RESULTS

In our case, the progression of the symptoms and the performance decrement required explantation, followed by a complete recovery. Reviewing the literature revealed only three reports concerning cases of proven endocochlear phlogosis that required revision surgery. Wound swelling/infection and vertigo remain the two most common complications of cochlear implantation. Failure of the device is the third most frequent complication (10.06% of all complications and 1.53% of cochlear implantations). Other rare conditions (such as granulating labyrinthitis with cochlear fibrosis, ossification and erosion, silicone allergy and the formation of a biofilm around the internal device) are possible and unpredictable. Although rare (approximately 1%), such cases may require explantation.

CONCLUSIONS

Despite efforts by both surgeons and manufacturers, device-related and surgical complications still occur. These and other rare conditions demand specific management, and their frequency may be underestimated. Further studies are needed to assess more realistic rates of complications and devise more efficient strategies for early diagnosis and treatment.

[Vestibular dysfunction after cochlear implant in adults]

BACKGROUND

According to the literature, clinical vertigo after cochlear implant (CI) occurs in 0.33-75%, a peripheral vestibular loss of function in 20-75%.

MATERIALS AND METHODS

Between 2006 and 2009, 30 adults were implanted with a 22-channel Nucleus Freedom CI (41 operations). Cochleostomy was performed anterocaudal of the round window and the electrode inserted using the "off-stylet" technique into the scala tympani.

RESULTS

Clinical vertigo occurred after 10/41 (24.4%) operations: acutely in 5/41 (12.2%), continuous in 1/41 (2.4%), delayed for 6-18 months in 5/41 (12.2%). In the calorimetry, 3/27 (11.1%) vestibular organs displayed a loss of function (p = 0.16). Three of 8 patients (37.5%) with clinical vertigo after surgery showed a loss of vestibular function (p = 0.08).

CONCLUSION

Using the described techniques and materials, the risk of loss of vestibular function and the incidence of clinical vertigo can be minimized. Postoperative vertigo did not occur more often in patients with preoperative diminished vestibular function than in patients with normal findings. Therefore, preoperative vestibular function tests cannot be an indicator for the frequency of vertigo after CI. If one vestibular organ shows preoperative dysfunction, the non-affected normal vestibular organ should not be implanted.

The temporalis pocket technique for cochlear implantation: an anatomic and clinical study

OBJECTIVE

To describe the surgical anatomy and clinical outcomes of a technique for securing cochlear implant receiver/stimulators (R/S). Receiver/stimulators are generally secured by drilling a custom-fit seat and suture-retaining holes in the skull. However, rare intracranial complications and R/S migration have been reported with this standard method. Newer R/S designs feature a low profile and larger, rigid flat bottoms in which drilling a seat may be less appropriate. We report a technique for securing the R/S without drilling bone.

STUDY DESIGN

Anatomic: Forty-eight half-heads were studied. Digital photography and morphometric analysis demonstrated anatomic boundaries of the subpericranial pocket (t-pocket). Clinical: Retrospective series of 227 consecutive Cochlear implant recipients implanted during a 2-year period using either the t-pocket or standard technique. The main outcome measures were rates of R/S migration and intracranial complications. Minimum follow-up was 12 months.

RESULTS

The t-pocket is limited anteriorly by dense condensations of pericranium anteriorly at the temporal-parietal suture, posteroinferiorly at the lamdoid suture, and anteroinferiorly by the bony ridge of the squamous suture. One hundred seventy-one subjects were implanted using the t-pocket technique and 56 using the standard technique, with a minimum follow-up of 12 months. There were no cases of migration or intracranial complications in either group.

CONCLUSION

The t-pocket secures the R/S with anatomically consistent strong points of fixation while precluding dural complications. There were no cases of migration or intracranial complication noted. Further trials and device-specific training with this technique are necessary before it is widely adopted.

Bacterial infection complications in children with cochlear implants in the Czech Republic

OBJECTIVE

Studies describing wound infections after cochlear implantation are rare. Meticulous operative techniques and sufficient surgical skill can help to avoid severe postoperative complications. Minor complications such as seromas, superficial wound infections, skin emphysema, and swelling can all be successfully treated using conservative methods. Serious problems, however, could be caused by Pseudomonas aeruginosa and Staphylococcus aureus infections.

STUDY DESIGN

Retrospective case series.

SETTING

Pediatric cochlear implant center in the Czech Republic.

RESULTS

In our cohort of 360 children operated on between 1994 and 2009, there were no major surgical complications. However, there were four serious wound infections, two of which resulted in explantation of the device. Two patients with a well-bordered abscess formation were successfully treated with antibiotics and drainage. Explantation was required in another two children with refractory P. aeruginosa infection. Despite favorable sensitivity to a number of antibiotics, intravenous and intensive local treatment failed. After explantation, the operative sites healed immediately. Both children were successfully implanted contralaterally 6 months later. Detailed bacteriological tests from different parts of the device were performed.

CONCLUSION

The consequences of explantation were discussed in our cochlear implant center. Confirmed by the microbiological results and reports in the scientific literature, it seems preferable to cut the electrode near the cochlear array and leave it inside the cochlea in order to use the same ear for reimplantation at a later date.

[Present state of cochlear implant treatment in adults and children]

The technique of cochlear implantation was the first method which allowed replacement of a sense organ by a (partially) implantable electronic prosthesis. By this method the cells of the spiral ganglion of the cochlea are directly stimulated by the electrodes introduced into the cochlea, bypassing the functions of the outer and middle ear as well as the cochlea. Treatment with a cochlear implant (CI) has been established over the last 20-30 years as a reliable method for restoring hearing in adults and children with severe hearing disorders and is now a routine method in many centers. For optimal results in understanding speech and for children in the speech development phase, rehabilitation must be an integral part of the total treatment and follow soon after implantation. To achieve this early diagnosis of hearing difficulties or deafness is necessary, which is simplified by a consistent hearing screening of newborns, now a statutory procedure in Germany.

Extradural haematoma presenting as a contralateral sixth nerve palsy after cochlear implantation

Intracranial complications after cochlear implantation are rare. The authors present the case of a 13 month old boy with a contralateral abducens nerve palsy following cochlear implantation that led to the diagnosis of an extradural haematoma on computerised tomography scanning. The abducens palsy resolved after evacuation of the haematoma and the patient made an excellent recovery. The literature is reviewed and the mechanism of injury discussed.

Four years' experience with the minimally invasive surgical approach in cochlear implant surgery

This is a prospective study on 808 profoundly or totally deaf patients who underwent either unilateral or bilateral cochlear implantation, involving a minimally invasive surgical approach, at the Medical University of Hannover's Department of Otolaryngology between May 2001 and May 2005. Advanced Bionics, Cochlear and MED-EL devices were used, the latter having been in use at our department since the beginning of 2003. The aim of our investigation was to determine the optimal surgical technique, evaluate safety aspects and gauge patient satisfaction with this minimally invasive surgical approach during cochlear implantation. Surgical technique is analysed. Complications such as skin flap problems did not occur. The use of this minimally invasive surgical technique did not increase the surgical risk. This procedure proved both cosmetically and psychologically beneficial for patients, especially for children and their parents.

Management of otitis media-related diseases in children with a cochlear implant

CONCLUSION

In all, 4 of 19 children with a cochlear implant (CI) with otitis media developed cholesteatoma. The insertion of a CI may interfere with normal mastoid pneumatization, stimulate mucosa as foreign body, or act as a nidus of infection. Regular follow-up is necessary for children with a CI at the prevalent ages of otitis media. Antibiotic treatment is suggested whenever acute otitis media is suspected, to prevent chronic progress of infection, cholesteatoma, or even meningitis.

OBJECTIVE

To evaluate treatment modality and outcomes of otitis media-related diseases in children with a CI.

PATIENTS AND METHODS

This was a retrospective case review in a tertiary referral center of Taipei Medical University, Chi Mei Medical Center. All patients had a history of otitis media or related disease in the implanted ear. Treatments included antibiotics, tympanotomy, and tympanomastoidectomy.

RESULTS

In all, 19 of 186 children with a CI were identified as having otitis media, and 4 of them as having cholesteatoma. Among the others, 10 were identified as having acute otitis media, 4 as having middle ear effusion, and 1 as having mastoiditis in the implanted ear. Surgery was performed in children with cholesteatoma and mastoiditis. The CIs of three children were eventually explanted to eradicate cholesteatoma.

Does the surgical approach in cochlear implantation influence the occurrence of postoperative vertigo?

Objective

To investigate the impact of different cochleostomy techniques on vestibular receptor integrity and vertigo after cochlear implantation.

Study Design

Retrospective cohort study.

Subjects

A total of 62 patients (17 to 84 years of age) underwent implantation via an anterior or round window insertion approach.

Methods

Two groups of cochlear implant patients were compared with respect to their pre- and postoperative vestibular function and the occurrence of postoperative vertigo. The data were related to the different cochleostomy techniques. The patients were tested by a questionnaire (dizziness handicap inventory, DIH), caloric irrigation (vestibulo-ocular reflex, VOR) for the function of the lateral SCC and by vestibular evoked myogenic potential (VEMP) recordings for saccular function. RESULTS: Significant differences of postoperative VEMP responses (50% vs 13%) and electromystagmography (ENG) results (42.9% vs 9.4%) were found with respect to the 2 different insertion techniques. The number of patients with vertigo after the surgery as evidenced by DHI (23% vs 12.5%) was significantly different.

Conclusion

The used round window approach for electrode insertion should be preferred to decrease the risk of loss of vestibular function and the occurrence of vertigo.

Surgical emphysema: a rare complication following cochlear implantation

A case report of surgical emphysema following adult cochlear implantation. The clinical picture, investigations and management of this rare case will be discussed.

A multicenter study of device failure in European cochlear implant centers

OBJECTIVE

To evaluate the failure rate of cochlear implant systems across a range of European implant centers.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary care cochlear implant centers in Europe.

MATERIAL AND METHODS

A postal questionnaire was designed to assess the incidence and mode of total device failure and was sent to 34 European clinics.

RESULTS

Twenty seven (79%) centers replied providing data on 12,856 devices of which 488 (3.79%) had undergone total device failure. Of 8,581 Nucleus devices (Cochlear, Sydney, Australia), 169 had failed; of 1,761 Advanced Bionics systems (Advanced Bionics, Sylmar, USA), 123 had failed; of 1987 Med El devices (Med-El, Innsbruck, Austria), 179 had failed; and of 527 MXM devices (Laboratoires MXM, Vallauris, France), 17 had failed. Six (22%) centers never reported failures to competent authorities.

CONCLUSIONS

The study suggests that the overall reliability of cochlear implant systems is satisfactory but that reliability varies considerably between individual systems. There is a compelling need for agreed international definitions of failure and for the adoption of uniform reporting protocols. A common database, independent of the industry, would offer greater transparency to users and clinics.

Elimination of Facial Nerve Stimulation by Reimplantation in Cochlear Implant Subjects

HYPOTHESIS

Perimodiolar intracochlear electrodes with contacts facing towards the modiolus have limited current flow towards the outer wall of the cochlea and therefore, may reduce the occurrence of facial nerve stimulation (FN) in cochlear implant subjects.

BACKGROUND

Facial nerve stimulation is a well-known complication in cochlear implant treatment especially in the group of subjects with otosclerosis. The possible explanation of this side effect is a change of the electrical properties of the otosclerotic bone leading to leakage current and resulting in facial nerve stimulation.

METHODS

Four CI subjects who had been implanted with a Nucleus Mini22 device with a Nucleus Straight electrode between 9 to 12 years ago suffered from severe FN stimulation. Electrode contacts had to be switched off so that they could only use 4, 11, 13, and 15 electrodes of their usual set of 22. The switch off resulted in deteriorating speech understanding over time. Therefore, all subjects were reimplanted with a Nucleus 24R device with a Contour electrode. Preoperatively, the threshold of FN stimulation was obtained on all electrodes subjectively. Intraoperatively, FN stimulation thresholds were measured objectively with both, the old and the new device and were compared. NRT and SRT thresholds were also obtained with the reimplanted device to assure effective electrical stimulation of the auditory nerve.

RESULTS

In all four cases the postoperative fitting demonstrated no FN stimulation on all electrodes up to maximum comfortable level. The insertion of the Contour electrode array was complete in three cases, in one case the array could only be inserted partially similarly to the situation before the reimplantation. Speech perception tests showed a significant improvement in all subjects with the new device.

CONCLUSION

Electrodes with modiolar facing contacts and perimodiolar position like the Nucleus Contour electrode reduce the possibility of facial nerve stimulation significantly due to more focused electrical stimulation.

Kochleaimplantation bei Kindern im 1. Lebensjahr

BACKGROUND

The success of cochlear implants in children was followed by a stepwise reduction in age at time of surgery. As a result of newborn hearing-screening (NHS) and the reliable audiologic diagnostic procedure, the question is raised as to whether an implantation before the age of 1 year is effective and safe in terms of surgery and rehabilitation.

METHOD AND PATIENTS

This retrospective study included 27 children implanted before the age of 1 year (Gr. 1) and 89 children implanted between the age of 1 and 2 years (Gr. 2). Patient related data were analysed for individual history, surgery, rehabilitation and speech understanding.

RESULTS

The incidence of complications was not increased in Gr. 1. The fitting of a speech processor was effective and uneventful in all children. The development of hearing and speech understanding showed better results after 2 years in Gr. 1. This development is more obvious for absolute age and not to rehabilitation time.

CONCLUSION

In order to achieve an optimal timing for the development of speech understanding, cochlear implantation should be performed before the age of 2 years. This study revealed no additional risks for children in Gr. 1, but the development of speech understanding was better. As a consequence, cochlear implantation should be considered for very young children with an identified bilateral profound hearing loss.

Complications in Children with Long-Term Cochlear Implants

OBJECTIVES

To evaluate the complications in children who underwent cochlear implantation between 1991 and 2002 at Chi Mei Medical Center, Taipei Medical University.

METHOD

The medical records of 169 cases of pediatric cochlear implants from 1991 to 2002 with a follow-up period of 3-11 years were reviewed for demographics and complications. A follow-up phone call and clinical visits were performed to determine the long-term results.

RESULTS

The medical-surgical complications were facial nerve stimulation, transient dizziness, flap breakdown, minor change of taste, cholesteatoma, otitis media with effusion and mastoiditis. The device-related complications included 4 device failures and 1 device breakage in a traffic accident.

CONCLUSION

Chronic otitis media and cholesteatoma developed in children as long-term complications and surgical challenges. Nevertheless, cochlear implantation surgery in children is a reliable and safe procedure with a low percentage of severe complications. To prevent cholesteatoma formation, parents are advised to schedule a regular ENT consultation at least yearly for early identification and treatment in the stages of acute otitis media or drum retraction.

[Cochlear implants using the Ultracision harmonic scalpel]

We have evaluated the utility, indications and disadvantages of the Ultracision harmonic scalpel, in the cochlear implants, and his advantages compare to other electrocoagulation's systems. These aspects were evaluated in 50 cases of cochlear implants, made along the last years. We concluded that the Ultracision harmonic scalpel is indicated, mainly, in the otology field, in these situations in wich the cochlear implant is in the cochlea, and is mandatory the use of an electrocoagulation system. In this situation, the Ultracision harmonic scalpel was quick, safe and sure, and with many advantages, over the traditional scalpel and the bipolar diathermy.

Impact to the head increases cochlear implant reimplantation rate in children

OBJECTIVE

To describe the outcome of cochlear implantation in children and to discuss the cause and management of cochlear reimplantation.

STUDY DESIGN

Retrospective chart review.

METHODS

The medical records of 110 patients younger than 18 years of age, who underwent cochlear implantation at the Department of ORL, Head and Neck Surgery, of the University of Kiel, Germany, were reviewed for demographics, complications, and history of revision surgery. The patients had previously had implantation with either Nucleus (including the Contour) devices or MED-EL devices.

RESULTS

Length of use before cochlear explanation ranged from 4 days to 3.9 years. Reimplantation was caused by traumatic device failure, wrong electrode insertion and infection of implanted area. Results indicated a reimplantation rate of 5.4% in children compared to 0.8% in adults, mostly resulting from the greater risk of children receiving an impact to the head. Postoperative performance data showed no decrease in scores taken before failure.

CONCLUSIONS

Though young children who are developing their motor skills are probably at greater risk of a cochlear reimplantation resulting from device failure following head trauma, surgical revision with reimplantation can be performed safely and without decrement to performance.

[Cochlear implants in Aragón]

Cochlear implants are, actually, one of the major advances in the treatment for profound deafness. His use is, already, a routine in the daily practice of our specialty. Due to its special aspects, cochlear implants have to be done following a protocol that organizes and coordinates the different aspects of the diagnoses and treatment of profound deafness, in the different administrative and geographical fields. The health system in our country and the smale dimension of our area, has taken us to create and follow a special program in which all the available resources are used. Following this protocol, we have performed 63 cochlear implants, in the last 10 years. We show here the results and complications.

Epidural Hematoma After Cochlear Implantation In A 2.5-Year-Old Boy

OBJECTIVE

Report a case of an epidural hematoma after cochlear implantation in a 2.5-year-old boy, the diagnostic and therapeutical emergency management, as well as the postinterventional course and rehabilitation of the child.

STUDY DESIGN

Retrospective case review.

PATIENT

Two and a half-year-old boy, suffering from early onset, profound sensorineural hearing loss had been diagnosed at an age of 1.5 years, which had been more severe on the right side initially, but had progressed to bilateral deafness. INTERVENTION AND COMPLICATION: Cochlear implantation on the left side, followed up by an extensive epidural hematoma, causing intracranial compression with a midline shift of 15 mm to the right side. This initial complication was followed up by arterial infarction not only of the middle but also the posterior as well as the anterior cerebral artery, most likely caused by incarceration through the tentorium.

RESULTS

After immediate neurosurgical intervention and intensive care treatment including low-dose anticoagulation and high doses of corticosteroids, the child recuperated completely within 3 weeks without any remaining neurologic deficits.

CONCLUSION

In cochlear implantation, especially if placement of the implant housing is associated with considerable bone work, epidural hematoma has to be considered as an extremely rare, but life-threatening, complication.

Labyrinth dysfunction 8 months after cochlear implantation: a case report

OBJECTIVE

Investigate whether the cochleostomy is a possible port of entry for pneumolabyrinth and a resulting vertigo in patients provided with a cochlear implant.

STUDY DESIGN

Retrospective case review.

SETTING

Ludwig-Maximilians University of Munich, Hospital Grosshadern.

PATIENT

62-year-old patient who underwent implantation of a HiFocus II cochlear implant with positioner from Advanced Bionics (CLARION). Eight months postoperatively, the patient reported rotatory vertigo and right-side tinnitus after he had blown his nose harder than usual during an episode of rhinitis.

INTERVENTIONS

Preoperative and postoperative testing of both the petrosal bone with a CT scan and of balance function.

MAIN OUTCOME MEASURE

Air inclusion in the labyrinth.

RESULTS

In contrast to the preoperative high resolution computed tomography (CT) scan, air inclusion was seen in the labyrinth during the episode of vertigo. At the same time, balance function tests with Frenzel glasses revealed both spontaneous and provoked horizontal nystagmus to the right side. At follow-up 8 weeks later, the level of vertigo had significantly decreased. Twelve months later, the control CT showed the cochlear implant positioned correctly and no visible air in the labyrinth.

CONCLUSION

It is known that placement of the HiFocus II with Positioner from CLARION requires a relatively large cochleostomy of 1.5 mm. Moreover, in the connective tissue seal between the electrode and the positioner, the latter reaches into the tympanic cavity, and this is possibly the weak point. Further investigation will be needed to determine whether the large cochleostomy with the HiFocus II with positioner increases the predisposition to labyrinth dysfunction.