Intracranial complications of cochlear implantation

A monocenter, patient-blinded, randomized, parallel-group, non-inferiority study to compare cochlear implant receiver/stimulator device fixation techniques (COMFIT) with and without drilling in adults eligible for primary cochlear implantation

BACKGROUND

During the cochlear implantation procedure, the receiver/stimulator (R/S) part of the implant is fixated to prevent postoperative device migration, which could have an adverse effect on the position of the electrode array in the cochlea. We aim to compare the migration rates of two fixation techniques, the bony recess versus the subperiosteal tight pocket without bony sutures.

METHODS AND ANALYSIS

This single-blind randomized controlled trial will recruit a total of 112 primary cochlear implantation adult patients, eligible for implantation according to the current standard of practice. Randomization will be performed by an electronic data capture system Castor EDC, with participants block randomized to either bony recess or standard subperiosteal tight pocket in a 1:1 ratio, stratified by age. The primary outcome of this study is the R/S device migration rate; secondary outcomes include patient-experienced burden using the validated COMPASS questionnaire, electrode migration rate, electrode impedance values, speech perception scores, correlation between R/S migration, electrode array migration and patient complaints, assessment of complication rates, and validation of an implant position measurement method. Data will be collected at baseline, 1 week, 4 weeks, 8 weeks, 3 months, and 12 months after surgery. All data analyses will be conducted according to the intention-to-treat principle.

DISCUSSION

Cochlear implantation by means of creating a tight subperiosteal pocket without drilling a bony seat is a minimally invasive fixation technique with many advantages. However, the safety of this technique has not yet been proven with certainty. This is the first randomized controlled trial that directly compares the minimally invasive technique with the conventional method of drilling a bony seat.

TRIAL REGISTRATION

Netherlands Trial Register NL9698. Registered on 31 August 2021.

Variability in surgical techniques for cochlear implantation: an international survey study

OBJECTIVE

This study aimed to gain insight into current practices regarding the surgical techniques used for positioning and fixation of internal components of the cochlear implant.

METHODS

A questionnaire focused on surgical techniques used for cochlear implantation was distributed among 441 cochlear implant surgeons. Descriptive statistics were reported.

RESULTS

The questionnaire was completed by 59 surgeons working in 13 different countries. The most preferred incision shapes were the S-shape (41%) and the C-shape (36%). The preferred implantation angle for the receiver/stimulator device was either 45° (64%) or 60° (30%), relative to the Frankfurter Horizontal Plane. Most respondents used a drilled bony well with (42%) or without a subperiosteal pocket (31%) to fixate the receiver/stimulator device. All respondents used the facial recess approach. Most used the round window insertion technique to enter the scala tympani (73%). Approximately half of the respondents preferred the lateral wall electrode array, whereas the other half preferred the perimodiolar electrode array. During their career, most (86%) changed their technique towards structure preservation and minimizing trauma.

CONCLUSION

This study indicates variability in the surgical techniques used to position and fixate the internal components of the cochlear implant. Additionally, surgical preference transits towards structure preservation and minimal invasiveness.

Surgical Factors Influencing Wound Complication After Cochlear Implantation: A Systematic Review and Meta-Analysis

OBJECTIVE

To identify perioperative surgical factors associated with wound complications following cochlear implantation (CI).

DATA SOURCES

PubMed, Web of Science, and Cochrane databases.

STUDY SELECTION

Eligible studies included peer-reviewed research in English evaluating wound complications (wound infection, skin flap breakdown/dehiscence, seroma/hematoma) following CI. Studies with paired samples were included in the meta-analysis.

DATA EXTRACTION

Surgical factors (techniques and perioperative management) in CI and reported wound complications were examined. Level of evidence was assessed using the Oxford Centre for Evidence-based Medicine guidelines and bias was assessed using the NIH Quality Assessment Tool.

DATA SYNTHESIS

Twenty-six studies representing 10,214 cochlear implantations were included. The overall wound complications rate was 3.1% (range 0.03-13.9%). Eleven studies contained paired data and were used for meta-analysis regarding three different surgical factors: incision length, implant placement method, and antibiotic usage. Longer incision lengths (≥7 cm) demonstrated a higher risk of wound complications (risk ratio 2.27, p = 0.02, CI 1.16-4.43). Different implant placement techniques (suture fixation versus periosteal pocket) (p = 0.08, CI 0.92-3.69) and postoperative antibiotic regimens (postoperative use versus none) (p = 0.68, CI = 0.28-7.18) were not associated with differences in wound complication rates following CI.

CONCLUSIONS

Overall rate of wound complications following CI is low. Shorter incision length is associated with lower risk of wound complications. Differences in perioperative techniques and practices regarding implant placement and antibiotic use were not associated with differences in wound complication rates. Considering the low number and quality of studies, there is a need for research in CI outcomes using paired sample prospective designs and standardized reporting.

Complications of Cochlear Implant Surgery: A Public Implant Centre Experience

Objectives:

To determine the prevalence of complications of cochlear implant surgery in children with congenital profound sensorineural hearing loss.

Methods:

This study retrospectively & consecutively reviewed charts of children who underwent cochlear implantation from July 2015 to July 2019 at Cochlear Implant Centre of Otolaryngology Department of Capital Hospital, Islamabad Pakistan. These included cases of both genders aged one to 12 years operated at least one year before the time of data collection. Basic demographic data, complications including major and minor complications and treatment received was noted and statistically analyzed using SPSS-23. Results were presented using descriptive statistics.

Results:

Current study included a sample of N=251 having a mean age of 4.05±2.15 years including 154(61.4%) males and 97(38.6%) females revealed a prevalence of complications of 16(6.4%) with 4(1.6%) major and 12(4.8%) minor complications. Wound infection and acute otitis media with frequency of 3(1.2%) each were the commonest complications, followed by , facial nerve twitching, tinnitus and vertigo, infection and extrusion; and device failure in 2(0.8%) each. However, there was no significant association of complications with age group and gender with P=0.344 and P=0.519 respectively.

Conclusion:

Present public sector implant program is characterized with a very low prevalence of complications of 16(6.4%) with 4(1.6%) major and 12(4.8%) minor complications. Wound infection and acute otitis media were the commonest complications.

Comparison of Cochlear Implant Device Fixation-Well Drilling Versus Subperiosteal Pocket. A Cost Effectiveness, Case-Control Study

OBJECTIVE

To compare surgical characteristics and complications between well drilling (WD) and subperiosteal pocket techniques (SPT) for receiver/stimulator (R/S) fixation of cochlear implant (CI), and conduct cost-effectiveness analysis.

STUDY DESIGN

Retrospective clinical study, decision-analysis model.

SETTING

Tertiary referral center.

PATIENTS

Three-hundred and eighty-eight CI recipients with a minimum of 6-months follow-up.

INTERVENTIONS

CI surgery using either WD or SPT for R/S fixation. A decision-analysis model was designed using data from a systematic literature review.

MAIN OUTCOME MEASURES

Surgical operation time, rates of major and minor long-term complications were compared. Incremental cost-effectiveness was also estimated, comparing the two methods of fixation.

RESULTS

We compared 179 WD with 209 SPT. Surgery time was significantly shorter in SPT (148 versus 169 min, p = 0.001) and remained significant after adjustment for possible confounders. Higher rates of major complications requiring surgical intervention were found with SPT (10.5% versus 4.5%, p = 0.042), however, the difference was not significant after adjusting for follow-up time (47.8 versus 32.5 months for SPT, WD respectively; p < 0.001). The incremental cost-effectiveness ratio for WD (compared with SPT) was $48,795 per major complication avoided, which was higher than the willingness-to-pay threshold of $47,700 (average cost of 2 h revision surgery).

CONCLUSIONS

SPT was found to be faster but potentially risks more complications, particularly relating to device failure. Further long-term studies are required to validate these differences. Based on data from the current literature, neither of the methods is compellingly cost-effective over the other, and surgeons can base their choice on personal preference, comfort, and previous training.

The Diploic Veins: A Comprehensive Review with Clinical Applications

The diploic veins serve as an important connection between the extracranial and intracranial venous systems. They change in size during growth from adolescence to adulthood. The diploic space has been identified as an additional site of reabsorption of cerebrospinal fluid (CSF). Herein, the anatomy and physiology of the diploic veins are reviewed.

Subdural Hematoma: A Rare Adverse Complication From Bone-Anchored Hearing Aid Placement

OBJECTIVE

Bone-anchored hearing aids (BAHA) are bone conduction hearing aids commonly implantated by Ear, Nose, and Throat surgeons. We present the first documented case of a subdural hematoma secondary to primary fixation of a BAHA.

PATIENT

We present a 65-year-old male patient undergoing a left sided BAHA for bilateral chronic ear infections and difficulty wearing conventional hearing aids. The procedure was uneventful, however, the patient developed a postoperative large acute left temporoparietal intracerebral hematoma associated with an ipsilateral acute subdural hematoma. This required emergency transfer to the local tertiary neurosurgical center for a left decompressive craniotomy and evacuation of the hematoma.

RESULTS

The patient required a prolonged stay on an intensive care unit and was eventually discharged to the community for on-going neurological rehabilitation.

CONCLUSION

This is a rare and devastating complication BAHA surgery. Otologist, general ENT surgeons, and neurosurgeons should be aware of this life-threatening complication of BAHA surgery.

Radiologic Evidence of Cochlear Implant Bone Bed Formation Following the Subperiosteal Temporal Pocket Technique

Objective

To compare the thicknesses of bone beneath the internal receiver stimulator (IRS) with the symmetric contralateral unimplanted side in postoperative temporal high-resolution computed tomography (CT) and/or cranial CT of the patients for whom cochlear implants were secured by the subperiosteal temporal pocket technique.

Study Design

Case series with chart review.

Setting

Tertiary care hospital, cochlear implant referral center.

Subjects

Cochlear-implanted pediatric patients with postoperative temporal high-resolution CT and/or cranial CT were reviewed. The study group included 10 patients with Clarion devices (Advanced Bionics, Valencia, California).

Methods

Thicknesses of bone were recorded independently by 2 radiologists in the standardized coordinates of proximal, middle, and distal segments of both the IRS bed and the contralateral unimplanted side in each patient. Bone thickness differences in the proximal, middle, and distal segments of IRS were investigated. Any correlation between bone thickness differences and patient age at implantation or duration of implantation was also investigated.

Results

Mean values of bone thicknesses obtained from the IRS side and contralateral unimplanted side were, respectively, as follows: 2.40 ± 0.80 mm and 4.17 ± 1.10 mm in the proximal segment ( P = .0001); 1.48 ± 0.33 mm and 3.02 ± 0.85 mm in the middle segment ( P = .0001); and 2.13 ± 0.41 mm and 3.40 ± 0.61 mm in the distal segment ( P = .006). Significant positive correlation was found between patient age at implantation and decrement values in the distal segments ( r = 0.681, P = .03).

Conclusion

The subperiosteally secured IRS eventually creates its own well on the skull vault. This new radiologic evidence shows that device migration risk decreases over time, and it supports the findings of other clinical series showing device stability using the subperiosteal pocket technique.

Intraoperative seizure and cerebrospinal fluid leak during adult cochlear implant surgery

OBJECTIVE AND IMPORTANCE

To report a rare case of cerebrospinal fluid gusher and subsequent seizure immediately after cochlear implant electrode insertion.

CLINICAL PRESENTATION

After the cochlear implant electrode was inserted, brisk flow of 10 mL of cerebrospinal fluid was seen. The electrode was promptly inserted and the leak was additionally sealed with fascia. Seconds later, the patient had a tonic-clonic seizure lasting 30 seconds. Two additional episodes occurred during the case. Her postoperative course was uneventful with no subsequent seizures. The device has been successfully activated. Intervention & Technique: Postoperative imaging showed correct intracochlear placement of the electrode as well as an incidental enlarged vestibular aqueduct. Neurology consultation including electroencephalogram was unremarkable.

CONCLUSION

To our knowledge, this is the first report of a seizure temporally associated with cochlear implant electrode insertion. The significance and possible casual relationship between these two events is discussed.

228 Cases of Cochlear Implant Receiver-Stimulator Placement in a Tight Subperiosteal Pocket without Fixation

Objectives

(1) To investigate the outcomes of cochlear implant receiver-stimulator (RS) placement using a tight subperiosteal pocket technique without device fixation and (2) to compare the efficiency of this approach with the traditional bony well and trough technique.

Study Design

Case series with planned chart review.

Setting

Single tertiary academic referral center.

Subjects and Methods

All cochlear implant surgeries utilizing a tight subperiosteal pocket without additional fixation or use of a bone well were identified retrospectively. Revision cases were only included if the tight subperiosteal pocket technique was used during the initial surgery. Patients with less than 6 months of postoperative follow-up were excluded. Primary outcome measures included RS migration, flap complications, device failure, and percentage reduction in operative time.

Results

Two hundred twenty-eight cases (average age 45.3 years) met inclusion criterion and were analyzed. At a mean follow-up of 18.1 months, no patient experienced RS migration. One patient experienced a postoperative hematoma that was managed with observation. One patient developed a surgical site infection that resolved following exploration and intravenous antibiotics. The subperiosteal pocket technique resulted in an 18.9% reduction in total operative time compared to a more conventional RS placement method ( P < .01).

Conclusions

The tight subperiosteal pocket without fixation is a safe, durable, and time-saving technique for RS placement during cochlear implantation. Notably, device migration and flap complications are very uncommon.

Pediatric cochlear implant revision surgery and reimplantation: an analysis of 957 cases

OBJECTIVE

In this study causes, risk factors, prevention strategies, diffuculties encountered during revision cochlear implant surgery, reimplantation in pediatric age group were evaluated.

METHODS

Charts of 957 CI patients younger than 18 years of age implanted at Izmir Bozyaka Teaching and Research Hospital between 1998 and July 2012 and 18 referred CI complications at same age group were retrospectively evaluated. Revision and reimplantation surgeries were systematically reviewed.

RESULTS

We encountered 26 surgical complications in 24 patients and 36 device related problems in 36 patients. Eighteen referred cases including 7 surgical complications and 11 device related problems were also evaluated. A total number of 80 complications were evaluated. In 11 cases conservative management was successful, 19 revision surgery was performed but we failed in 4 cases. We reimplanted 48 cases and 4 additional cases were implanted after failed revision surgery. Implant was extracted in one case. In one case we could implant the other side. Forty-six of reimplantations were done in one stage surgery, 5 cases required second stage surgery.

CONCLUSIONS

Surgical complications and device related problems of cochlear implantation may be different in children and majority of them require revision surgery or reimplantation. Although surgical problems leading to revision surgery and reimplantation are expected to diminish by experience every center has to deal with device failures. Both revision surgery and reimplantation require extra care and it should be better carried out by experienced surgeons. Implant performances are expected to be comparable with primary implantations.

Early complications following cochlear implantation in children and their management

OBJECTIVES

To report the early postoperative complications of cochlear implantation (CI) in the pediatric population and discuss the intervention measures.

METHODS

We retrospectively analyzed 260 consecutive pediatric cochlear implantations performed at the First Affiliated Hospital of Zhengzhou University between March 2010 and July 2013. All patients were younger than 12 years old at the time of implantation, with a mean age of 4.3 years, and 47 cases had inner ear malformations. Complications correlated to age at CI and inner ear malformations were analyzed using the χ(2) test.

RESULTS

Of the 260 patients, early postoperative complications were observed in 17 (6.54%) cases, of which 16 (6.15%) were minor and one (0.38%) was major, none required surgical device removal or reimplantation. Among the 16 minor complications, transient vertigo was the most common (nine cases, 3.46%), three (1.15%) of them with severe CSF gusher during the surgery; followed by transient facial nerve palsy (two cases, 0.77%, both were reversible); external auditory canal injury, subcutaneous hematoma each in two cases (0.77%), and minor dural injury in one case (0.38%). One major complication included an epidural hematoma in a 7-year-old boy who recovered completely without any neurologic deficits following immediate evacuation. Inner ear malformations were significantly associated with the surgical complications, especially vertigo and gusher (P<0.05).

CONCLUSIONS

Cochlear implantation in children is fairly a safe procedure with a relatively low complication rate. The most common early postoperative complications are minor, but serious and life threatening complications rarely may occur. Awareness of complications helps clinicians to adopt the specific preventive measures and immediate interventions so that the outcome will be successful.

Cochlear implant fixation using a subperiosteal tight pocket without either suture or bone-recess technique

OBJECTIVES/HYPOTHESIS

To assess the complication and migration rates associated with the fixation of cochlear implant receiver-stimulators using a subperiosteal tight pocket without either suture fixation or bone recession.

STUDY DESIGN

Dual-institution retrospective case review.

METHODS

A retrospective case review was conducted at two tertiary referral centers. All patients who underwent cochlear implantation with device fixation using a subperiosteal tight pocket without suturing over the device or recessing of the receiver stimulator in bone were identified. There was a minimum follow-up period of 6 months. Outcome measures included intraoperative and postoperative complications, including evidence of device migration associated with interference with external device use or the need for revision surgery. Other outcome measures included soft tissue flap complications.

RESULTS

Sixty-two patients were identified with a mean age of 39 years, (range 1.5-5 years). The average follow-up period was 32.6 months (range 6-120 months). Device manufacturers included Cochlear Corporation (Denver, CO) (n=44), MED-EL (Durham, NC) (n=12), and Advanced Bionics (Valencia, CA) (n=6). There were no associated intraoperative complications related to subperiosteal pocket fixation of the receiver stimulator, and no cases of migration were identified.

CONCLUSION

Fixation of the cochlear implant receiver stimulator using a subperiosteal tight pocket without either suture fixation or bone recession has been demonstrated to be feasible across a range of patient demographics and cochlear implant devices. This method of fixation appears to allow for an efficient and minimally invasive approach without compromising patient safety or device performance.

LEVEL OF EVIDENCE

4.

Subdural haematoma as a rare complication of cochlear implantation: case report and literature review

OBJECTIVE

To report a case of subdural haematoma occurring as an extremely rare and life-threatening complication of cochlear implantation, and to explore the causative association between intracranial haemorrhage and cochlear implantation surgical techniques. This association has not previously been reviewed in depth.

CASE REPORT

A three-year-old boy was diagnosed with a large subdural haematoma, one week after cochlear implantation. After emergency evacuation of the haematoma, the patient made an excellent recovery and was discharged from hospital without any neurological deficit.

RESULTS

Mechanisms of injury are discussed and the literature reviewed, focusing on the possible causes of intracranial haemorrhage identified after cochlear implantation. Notably, bone drilling had been used in all reported cases, and the probable causative injury had always occurred after such drilling.

CONCLUSION

The issue of bone drilling during cochlear implantation is raised, and alternative methods of implant housing suggested, in order to avoid intracranial haemorrhage.

A simplified fixation of the new thin cochlear implant receiver-stimulators in children: long term results with the "back-pocket" technique

OBJECTIVE

To describe a simple technique for pediatric cochlear implant receiver-stimulators (R/S) fixation and long term results with it.

METHODS

Clinical sample include thirty-two children with severe-to-profound or profound hearing loss candidate for cochlear implantation. Low-profile devices were used (Med El Concerto and Nucleus CI512). The R/S was housed into a tight subperiosteal pocket carefully dissected behind the mastoidectomy. The pocket was closed with a single periosteal to bone suture around the posterior edge of mastoidectomy. No skull drilling was required for housing the device.

RESULTS

No intraoperative complications have been observed. 20% of operating time was saved. No migration of R/S over time was apparent at follow up.

CONCLUSIONS

The back-pocket technique seems effective in retaining the CI package and in optimizing surgical time and safety in pediatric cochlear implantation. It seems particularly suitable with new generation low profile CI devices.

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.

Delayed retroauricular cerebrospinal fluid (CSF) collection in cochlear implantation

In the literature, this is the first description of a delayed retroauricular cerebrospinal fluid (CSF) collection in a child after 18 months of cochlear implantation. During surgical revision, anomalous thinning of the dura and leakage of CSF was found beneath the receiver, requiring local sealing and repositioning. Exposure of the dura is a procedure usually performed during housing of the receiver to avoid excessive protrusion of the implant in subjects with insufficient bone thickness. In most cases, this has proved to be a safe procedure. However, in some cases, as in children, exposure of the dura should be undertaken with care.

Complications of cochlear implantation in adults

OBJECTIVES

We describe our experience of intraoperative and postoperative complications of cochlear implantation in an adult population.

METHODS

Between April 1986 and June 2010, the senior author (A.S.) performed 449 cochlear implantations in two different institutions. Of these, 212 implantations were in adults. The operative techniques were similar in all cases.

RESULTS

Complications were observed in 12 of the 212 adult cases (5.7%), of which 10 were major (4.7%) and 2 minor (1%). In 7 cases, reimplantation was necessitated by device failure (6 cases; 2.8%) or device extrusion (1 case; 0.5%). In 2 elderly patients (1%), a minor dural injury with a cerebrospinal fluid leak was controlled during the operation with temporalis fascia grafting. In 1 patient (0.5%), a subdural hematoma was observed after bipolar cauterization of a prominent diploic vein. In 2 subjects (1%), a wound infection was noted soon after implantation and was treated successfully on an outpatient basis.

CONCLUSIONS

Cochlear implantation is generally a safe procedure. The most common complication was device failure. Although complications in this adult population were rather uncommon, some of them were serious, and an immediate intervention was necessary for a successful outcome.

Cochlear reimplantation with same device: surgical and audiologic results

OBJECTIVES/HYPOTHESIS

To study to what extent it is possible to achieve identical insertion depths and to maintain the same performance after cochlear reimplantation.

STUDY DESIGN

Outcome research on a retrospective case series in a tertiary university referral center.

METHODS

Data were collected for 12 adults and three children who underwent reimplantation during the last 3 years with a new HiRes90K device with HiFocus 1J electrode owing to failure of the feed-through seal. Multislice computed tomography scans were used to compare positions of the original and newly placed electrode arrays. The speech-perception scores on a consonant-vowel-consonant word test before and after reimplantation were compared.

RESULTS

All reimplantations were successfully performed by two experienced cochlear implantation surgeons, and no complications were observed. Postoperative imaging showed that the average displacement of the new implant was only 0.59 mm. Reactivation of the implant gave immediate open set speech understanding in all patients, and speech perception rapidly returned to the previous level obtained with the original implant within weeks; it was even significantly better at the 3-month follow-up. No relation was found between changes in performance and the amount of displacement of the electrode array.

CONCLUSIONS

After cochlear reimplantation with the same device, electrode-array position can be accurately replicated and speech perception can be regained or even improved within weeks.

Complications in auditory brainstem implant surgery in adults and children

OBJECTIVE

Surgery for hearing restoration with auditory brainstem implantation (ABI) in patients with neurofibromatosis type 2 (NF2) is considered safe, as no increase in postoperative complications related to surgery or device implantation has been observed. Over the last 10 years, we have extended the use of ABI to nontumor (NT) adults and children with cochlear or cochlear nerve malfunctions who would not or did not benefit from a cochlear implant (CI). This article examines the complications encountered in ABI surgery in all patient groups.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

: One hundred fourteen ABI operations were performed in Verona (Italy) from 1997 to 2008 in 83 adults and 31 children. Thirty-six had NF2 (34 adults and 2 children), and 78 (49 adults and 29 children) had NT cochlear and cochlear nerve disorders.

INTERVENTION

A retrosigmoid-transmeatal approach was used in the NF2 cases, and a simple retrosigmoid approach was used in the NT patients.

MAIN OUTCOME MEASURES

Surgical complications are tabulated according to standard reporting categories and are presented separately and analyzed statistically for NF2, NT adults, and NT children. Complication rates are compared with those of CI and microvascular decompression surgery.

RESULTS

ABI surgery has a very low major complication rate, particularly in non-NF2 patients. Minor complications were easily controlled with complete resolution in all cases. Although the potential complications of intradural ABI implantation are more severe than those of a transmastoid approach for CIs, the actual observed complication rates in ABI candidates without NF2 tumors are comparable to those of CI surgery in both adults and children.

CONCLUSION

This study demonstrates that the ABI is a safe procedure when performed by an experienced surgical and rehabilitation team, and its benefits can be extended to a larger population of deaf patients.

Haematoma after cochlear implantation: management of a minor complication

CONCLUSIONS

The dimensions of the implant receiver and the material used have influenced the surgical approach leading to a reduction in complications. Ultrasonography of the haematoma is useful in the evaluation of dimensions, entity of fluid component and therapeutic options.

OBJECTIVE

Haematoma arising in the receiver area is considered a minor complication, nevertheless it can be complicated by infection and/or flap necrosis or fibrosis leading to difficulties in magnetic adherence of the receiver and rarely to explantation of the receiver. The objective of the study was to evaluate the clinical outcome of postoperative haematoma arising after cochlear implant surgery.

PATIENTS AND METHODS

This was a retrospective case series of 22 cochlear implant patients who developed post-implant haematoma over the receiver area. Haematoma extension and fluid collection were analysed via ultrasonography, implant type and predisposing factors such as trauma, coagulation disorders and type of skin incision.

RESULTS

Patients were divided into four groups on the basis of the main predisposing factor: coagulation disorders (n=7), trauma (n=3), revision surgery (n=6) and haematoma of unknown origin (n=6). The main factors correlated to haematoma onset were coagulation disorder, type of skin incision and flap revision. In all, 21 subjects had complete recovery and the speech perception performance was not compromised over time, while 1 subject (0.3%) with an extensive haematoma due to a pharmacologically induced coagulation disorder required explantation of the device.

Multicenter Evaluation of the Digisonic SP Cochlear Implant Fixation System with Titanium Screws in 156 Patients

Objectives:

We describe and evaluate the process of fixation of the Digisonic SP cochlear implant with two titanium screws.

Methods:

The characteristics of this implant allow cochlear implantation using a minimal incision, a subperiosteal pocket, and fixation with two titanium screws, without drilling a custom-fitted seat or creating suture-retaining holes in the skull. The fixation system relies on two tailfins for use of osseo-integratable screws, incorporated into the cochlear implant housing. The first version of this fixation system was modified after a case of device migration: The size of the titanium insert inside the silicone tailfin was increased. Data on 156 patients (8 months to 86 years of age) from a 4-year period in 6 cochlear implantation centers were retrospectively evaluated. Ten patients have undergone bilateral implantation.

Results:

Of 166 implantations, 4 postoperative infections and 1 device failure after head trauma were reported. No cerebrospinal fluid leaks or epidural hematomas were reported. One device migration was observed in the first series; no device migrations occurred in the second series.

Conclusions:

The fixation system with screws embedded in the Digisonic SP involves a fast and simple surgical technique that seems to efficiently prevent implant migration.

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.

Factors affecting choice of device by cochlear implant candidates

OBJECTIVE

To investigate the ways the various cochlear devices are chosen by candidates/surrogates and analyze the factors that influenced their decisions.

SETTING

University-affiliated tertiary referral center.

METHOD

: A questionnaire that included general items and questions on device's aesthetics, technical considerations, and quality was sent to 429 patients who underwent cochlear implantation between June 1997 and December 2006 in our department.

RESULTS

One hundred eighty-four questionnaires were returned, yielding a response rate of 42.9%. Some patients did not receive the questionnaires because of the postal address changes. In addition, recently implanted patients/their surrogates were more ready to answer on the questionnaire on decision-making process compared with those who received their devices before 2001. The Nucleus users were more influenced by the questions pertaining to the quality/reliability of the device than the aesthetic and technical aspects. The ABC users were more influenced by the aesthetic aspects, and the MED-EL users were generally influenced by all the groups of questions equally. Females used the Internet as the source of information on the devices significantly more than males, and their decisions were more influenced by their families than those of the males. In addition, the females were more influenced by the quality of a device's function compared with males. Pediatric candidates (aged 1-16 yr) were significantly more influenced by the experience of other implant users, the medical staff, and religious considerations than adults. Adults arrived at decisions more easily than children or their surrogates. The adults and older children were more influenced by the ease of the device's functioning compared with the young children.

CONCLUSION

Choosing the type of cochlear implant device is a highly individualized process that depends on various personal, social and cultural factors, and factors linked directly to the device itself.

Surgical and medical complications in different cochlear implant devices

CONCLUSION

There were no surgery-related complications among the patients in the current study. Positioner and removable magnets have been associated with postoperative problems, and the silicone devices were the only ones found by us to cause foreign body and allergic reactions.

OBJECTIVES

To evaluate the complication rate in patients who were implanted with cochlear devices manufactured by different companies.

PATIENTS AND METHODS

This retrospective study included all the patients who underwent cochlear implantation (138 Nucleus, 105 Med-El and 14 Clarion devices) via the suprameatal approach in our department during 2001-2007 and followed up for at least 18 months. Complications such as magnet displacement, foreign body reaction and protrusion of the positioner were considered as being implant-related. Allergy to implant, cholesteatoma, perforated tympanic membrane, intraoperative cerebrospinal fluid (CSF) leakage, wound breakdown, haematoma or seroma, and vestibular disturbances were considered to be patient-related.

RESULTS

Vestibular and wound problems emerged as the most common complications, but there were no significant differences in their rate of occurrence among the various devices. Explantation of the device was required in one case of foreign body reaction, one case of allergy to implant and one case of extrusion of the positioner followed by device failure.

Post-operative problems and complications in 313 consecutive cochlear implantations

Objective:

To describe problems and complications associated with cochlear implantation, and their management, in a Danish patient population comprising both paediatric and adult patients.

Design:

Retrospective chart review.

Setting:

Tertiary referral centre.

Subjects:

Three hundred and thirteen consecutive cochlear implantations were studied. The median age of the study population was 10 years. Sixty per cent of patients were children and 40 per cent were adult; 52 per cent were female and 48 per cent were male.

Intervention:

Two hundred and ninety-four patients received a Cochlear Nucleus®implant. The remaining 19 received an Advanced Bionics implant.

Main outcome measure:

Presence of problems and complications after cochlear implantation.

Results:

Post-operative complications were found in 15.7 per cent of patients. The majority of these complications (11.2 per cent) were minor; 4.5 per cent were major. The major complications included one patient with meningitis, one patient with multiple antibiotic resistantStaphylococcus aureusinfection of a radical cavity, and one diabetic patient who developed a severe skin infection and whose implant became exposed.

Conclusion:

Cochlear implantation is a safe procedure within the studied setting. However, it is essential that careful attention be paid to surgical planning and technique, and it is important that healthcare staff and patients be aware of the possible problems and complications.