Cochlear implant failures: lessons learned from a UK centre.

OBJECTIVES: To review our experience of cochlear implant failure and subsequent revision surgery, and to illustrate the experience we have gained by presenting a series of lessons learned. METHODS: A combined retrospective and prospective study of revision surgery in a UK regional cochlear implant centre. RESULTS: Of the 746 cochlear implantations undertaken, 33 (4.7 per cent of adults and 4.1 per cent of children) had a registered failure requiring re-implantation. The mean time to device failure was 60 months in adults and 35 months in children. Causes of cochlear implant failure were medical (n = 11), electrode displacement (n = 2), 'hard device failure' (n = 15) and 'soft device failure' (n = 5). Chronic suppurative otitis media and post-auricular mastoid abscess were the commonest causes of medical failure. There was one case of electrode array displacement as a direct result of skin flap revision surgery. In 80 per cent of cases, audiological performances were stable or improved following re-implantation. CONCLUSION: As the number of cochlear implants increase and patients outlive the lifespan of their devices, we will face a growing number of revision procedures. Audiologists and otologists should be competent in diagnosing and managing device failure and medical complications requiring cochlear re-implantation.

Bone anchored hearing aids: a second fixture reduces auditory deprivation in Cambridge.

Bone anchored hearing aids are well established for canal atresia, otosclerosis and chronic suppurative otitis media. Refinements in technique to maximise gain while keeping the complications to a minimum are desirable. This study was taken up in order to explore the potential advantage of a second or spare fixture placed at the time of primary surgery. A group of patients who underwent BAHA insertion at The Emmeline Centre for Cochlear Implants and Bone Anchored Hearing Aids, Addenbrookes hospital, Cambridge, UK with the placement of a spare fixture between 1999 and 2002 were compared to those patients with one fixture BAHA undertaken from 1991. Main outcome measures were complications encountered and duration of disability, (i.e. loss of hearing while waiting for new fixture placement). Both groups had similar incidence of complications, but the group with two fixtures suffered a shorter period of disability when a fixture failed. In our experience the use of second or spare fixture reduces the duration of disability. It engenders no additional complications with minimal extra cost.

Relative humidity of the external auditory canal in normal and abnormal ears, and its pathogenic effect.

OBJECTIVE: To find the relative humidity of the normal external ear canal and to demonstrate that the relative humidity of the external auditory canal was higher in abnormal ears, i.e. ears commonly associated with chronic discharge. SETTING: Secondary health care within the ENT departments of Addenbrooke's and Hinchingbrooke hospitals. DESIGN: A clinical observational study. PARTICIPANTS: Volunteers seen in ENT outpatients. Inclusion criteria for the normal ear group, was a normal ear with no history of infection or previous ear disease. Inclusion criteria for abnormal ear group commonly associated with chronic discharge. Exclusion criteria were the presence of pus or infection within the ear canal. METHOD: The relative humidity of the external ear canal was measured in normal and abnormal ears. Abnormal ears were grouped as those commonly associated with chronic discharge, mastoid cavities, tympanic perforations, recurrent otitis externa and hearing-aided ears. RESULTS: The range of relative humidity of normal ears is 40-70%. The humidity in abnormal ears was found to be significantly higher than the humidity in normal ears (P < 0.0001). CONCLUSION: The raised relative humidity in the external canal may explain the predisposition of certain abnormal ears to chronic discharge and infection. If the humidity of the canal could be brought down to a normal level, this could offer a new therapeutic treatment.

Bony overgrowth onto fixture component of a bone-anchored hearing aid.

An eight-year-old boy with Treacher Collins syndrome was fitted with a bone-anchored hearing aid. The audiometric result was excellent. Two years later, the abutment began to loosen and could not be tightened. It was thought that a new fixture would be required, with loss of use of the aid for three months. At surgery, bone was found to be growing over the hexagonal joint between fixture and abutment. A simple and rapid solution to this problem is described.

Subdural haematoma: a complication of cochlear implantation.

Cochlear implants have transformed the treatment of sensorineural hearing loss. They have few major complications. The authors describe the case of a man fitted with a cochlear implant who suffered a postoperative subdural haematoma. The haematoma is thought to have been caused by bleeding from emissary veins opened by the drill passages used to anchor the sutures for the receiver/stimulator. The authors have abandoned tie down sutures in cochlear implants, preferring an appropriately deep well with squared-off rims, which would secure the implant in place. They have had no further complications of this nature.

Cochlear implantation for progressive hearing loss.

The concept of neural plasticity and the early natural abilities of hearing children to acquire speech and language without instruction have led many authorities to advocate cochlear implantation before the age of 5 years in congenital deafness. Older children therefore become lower priority for scarce public funds because they are perceived to have passed the "window of opportunity" to learn speech, even if hearing is restored, and continue to rely on sign language. This paper shows that a subgroup of congenitally deaf children exists, who, having made good progress with conventional hearing aids, suffer a sudden or progressive hearing deterioration which arrests the speech development. Sixty children have been implanted in the Cambridge Programme, half for meningitis or other acquired losses and half for congenital prelingual deafness. Six of this latter group were congenital but progressive; their progress, deterioration, and improvement after implantation are summarised.

Paediatric cochlear implantation--the balance between professional caution and urgency of treatment.

There is a constant pressure to reduce the age of cochlear implantation in profoundly deaf children and thereby improve the auditory verbal language development in implantees. We effected a change in the regimen for the assessment of new referrals, and show how this has shortened the time taken in Cambridge to complete assessment and offer implantation in appropriate cases. We achieved a reduction in the duration of assessment of 2.8 months (which was not, however, statistically significant) by simple reorganization, while, we believe, maintaining the standards of assessment.

Physical and genetic characterization of the genome of Magnetospirillum magnetotacticum, strain MS-1.

Pulsed-field gel analysis of Magnetospirillum magnetotacticum, strain MS-1, indicates that the genome is a single, circular structure of about 4.3 mb. A few genes, identified by sequence similarity, have been localized and arranged in a map with dnaA, indicating the presumed origin of replication. There are at least two rRNA operons. In addition, rRNA genes are found on a 40 kb, possibly extrachromosomal, structure. The genes thought to be involved in magnetite synthesis, bfr and magA, are located in the same 17% of the genome. A one base pair-overlap seen in the bfr genes of MS-1 is found also in the closely related magnetic strain AMB-1, but not in the non-magnetic relative A. itersonii.

Per oral awake flexible fibre-optic laryngoscopy in the investigation of children with stridor without respiratory distress.

Use of rigid direct larygnoscopy (RDL) in the investigation of stridor in children is well recognized. This study presents awake flexible fibre-optic laryngoscopy (FFL) as the first line in investigation of children, under six months of age, who present with stridor without any associated respiratory distress. Using the per oral approach the procedures were conducted either in the out-patient department or in the ward. No anaesthesia, local or general, nor sedation was used. Of the 20 cases included in the study, in 16 (80 per cent) cases a working diagnosis was reached on awake FFL. Eleven had laryngomalacia, two subglottic stenosis, one glottic web and two were normal. Only four (20 per cent) cases needed RDL to reach a definitive diagnosis. There were no problems with the maintenance of the airway during the procedure. It is particularly useful in the diagnosis of functional abnormalities of the larynx, such as laryngomalacia and vocal fold palsies. Awake FFL using the per oral approach is a safe and reliable technique for reaching a working diagnosis in approximately 80 per cent of cases.

Computerized cochlear implant database system.

In an environment of clinical governance with increased demands for accountability it is very important that accurate, reliable and secure data records be maintained for easy retrieval, analysis and presentation when required. A database is a very versatile tool for this purpose. We describe here our experience in designing a database for cochlear implant patients in Cambridge, together with guidance for prospective designers in their chosen sub-specialty.

Further experience with fat graft obliteration of mastoid cavities for cochlear implants.

Obliteration of old mastoids and wet middle ears with autologous abdominal fat seems to be a reliable technique to render chronically discharging mastoid cavities or open middle ears dry and closed. This paper is the third in the series and looks at the intermediate results at five years. Of the 16 patients (one bilateral) 94.1 per cent of the ears are still dry and uninfected with closed external meati. Recurrent cholesteatoma was found in two patients at implantation and removed.

Cochlear implant failure due to unexpected absence of the eighth nerve--a cautionary tale.

We present a case of bilateral absence of the eighth cranial nerve in the internal auditory meatus (IAM). This caused total failure of responses after cochlear implantation in a six-year-old patient with congenital deafness. Pre-operative magnetic resonance (MR) imaging is important to show not only the anatomy of the middle and inner ears but also the structures in the IAM.

Surgical removal of 11 cochlear implants--lessons from the 11-year-old Cambridge programme.

This is a retrospective study of 10 patients (11 ears) out of 132 cochlear implant patients of the Cambridge cochlear implant programme. These patients have all been explanted. Individual problems have been studied, relevant literature reviewed and the pitfalls of implant surgery re-examined in the light of our experience.

Tracheostomy decannulation in children: approaches and techniques.

Various approaches and techniques are used in discontinuing tracheostomy in children. The variability in the use of resources is considerable. The objective of this study was to assess decannulation in children attended in a university-affiliated children's hospital. A retrospective analysis was made of the medical records of patients who had both tracheostomy (n = 177) and decannulation (n = 30) from 1985 to 1994. Tracheostomies, placed at a mean age of 38 months, were discontinued (on the average) 22 months later. Most children underwent airway endoscopy in the operating room in preparation for decannulation. Twenty-four children had downsizing, then capping of the tracheostomy as a functional trial. Six children underwent staged laryngotracheoplasty before decannulation. Two children had decannulation as part of a single-stage laryngotracheoplasty. Attention to at least one comorbid factor (e.g., pulmonary, neurologic, or cardiac disease) was important in the decannulation of each patient in this series. The individualization of tracheostomy decannulation is necessary for children.

The Scheibe cochlea deformity with macrocephaly: a case for single channel implantation.

An 11-year-old congenitally deaf child with bilateral primitive common cavity (Scheibe type) cochleosaccular dysplasia and benign familial macrocephaly was implanted with an extracochlear single channel device with an ear level speech processor. This paper describes the assessment, findings, dilemmas in decision making, surgical procedure and the favourable outcome after implanting. The relevant literature has been reviewed and our case is presented for the unusual combination of features.

Upper airway obstruction in children with Down syndrome.

OBJECTIVES: To analyze the complex nature of upper airway obstruction (UAO) and the response to surgery in children with Down syndrome. DESIGN: Retrospective medical chart review of all patients with Down syndrome who had UAO during a 5-year period. SETTING: Academic tertiary care children's hospital. PATIENTS: Seventy-one pediatric patients with Down syndrome who had significant UAO. Thirty-four patients had pulmonary artery hypertension; 44 patients had multiple sites of airway obstruction. The obstructive problems included lymphoid hyperplasia, macroglossia, narrow nasopharynx, laryngomalacia, congenital subglottic stenosis, tracheobronchomalacia, and tracheal stenosis. INTERVENTIONS: Children with Down syndrome and UAO underwent surgical procedures including tonsillectomy, adenoidectomy, tonsillar pillar plication, uvulopalatopharyngoplasty, anterior tongue reduction, tonguehyoid suspension, laryngotracheoplasty, and tracheotomy. MAIN OUTCOME MEASURES: Postoperative symptoms found on medical chart review, or parental telephone survey, or both, and results of postoperative diagnostic tests. Patients were grouped as "improved" or having "significant residual symptoms." RESULTS: Twenty-seven of the 55 surgical patients had mild obstructive symptoms, and most improved after tonsil or adenoid surgery, or both. The remaining patients were younger and had more severe symptoms, multiple sites of obstruction, and a high incidence of cardiac disease. Eleven (39%) of the 28 patients in this group had significant residual symptoms after surgery. Four children are tracheotomy-dependent. Five deaths occurred; 3 were attributable to the upper airway. CONCLUSIONS: Upper airway obstruction in children with Down syndrome often is a complex process with multifocal causes. Residual symptoms of airway obstruction are common after surgery. A comprehensive and individualized approach is important in the management of UAO in Down syndrome.

Patient performance over eighteen months with the Ineraid intracochlear implant.

We present our results with an 18-month follow-up for 15 adult patients treated with the Ineraid (formerly Symbion) four-channel intracochlear implant. All were postlingually deaf with profound or total hearing loss. Performance was tested in lipreading, implant only, and combined lipreading and implant modes using Boothroyd word lists, Bamford-Kowal-Bench (BKB) sentences, and Connected Discourse Tracking. Assessments were made after 10 hours of training and again at 9 and 18 months postimplantation. Mean scores at 18 months in the implant only mode were for Boothroyd word lists 39%, for BKB sentences 47%, and for connected discourse tracking 31 words per minute. In the combined implant and lipreading mode the mean scores were for Boothroyd word lists 85%, for BKB sentences 96%, and for connected discourse tracking 75 words per minute. A profile of implant performance against time shows that after 10 hours' training, 12 of the 15 subjects had some speech discrimination in the implant only mode for all three tests. When using their implant combined with lipreading, all 15 subjects improved their speech discrimination scores over those obtained with lipreading alone after 10 hours' training. By 9 months, all subjects had some speech discrimination in the implant only mode on all three tests. Between 9 and 18 months there was a slight trend toward improvement in implant performance, both when the implant was used alone and when it was combined with lipreading.

Cochlear implant results: a comparison of live-voice and videotaped tests.

The Cambridge Cochlear Implant Programme has so far implanted the Ineraid multichannel cochlear implant in 16 profoundly deaf adult patients; there has been a 9-month or longer follow-up period with these patients. We have evaluated these patients by open-set Bamford-Kowal-Bench (BKB) Standard Sentence List testing in two different delivery strategies, live-speaker testing by the same speaker and high-resolution videotaped testing. The performance in lip reading both before and 9 months after implantation has been tested, as well as performance with the implant alone and with the implant in conjunction with lip reading at the 9-month stage. We have compared the performance in these two delivery strategies and have found a significantly better performance in the live-speaker tests that is attributable to slower and perhaps more sympathetic delivery. We have also found evidence of a ceiling effect in the performance of the implant with lip reading in the live-speaker mode and, of greater importance, a floor effect in the performance of the implant alone with the videotaped test. These results and the implications for a complementary role of these two test-delivery modes are discussed.