Case report: early bilateral simultaneous cochlear implantation in a five-year-old following head injury complicated by acute bacterial meningitis.

Meningitis is an important cause of profound sensorineural hearing loss, especially in children. In this case, a five-year-old suffered a head injury complicated by bacterial meningitis and developed a profound hearing loss. Magnetic resonance imaging at four weeks following injury showed evidence of developing labyrinthitis ossificans and a decision was made to perform bilateral cochlear implantation at an early stage. This report outlines the progress of this interesting case to date and discusses the rationale for the decision to implant in this way.

Development of the Midland adult cochlear implant programme.

This paper describes the development of adult cochlear implantation in Birmingham over its first six years, from 1990 to 1996. During this time 366 patients were referred to the implant programme, female referrals outnumbered males 1.2:1. Eight per cent of referrals were over the age of 70. The annual rate of referral suggests a fairly steady demand for the service. Approximately one third of patients referred each year were subsequently implanted. The centre is currently performing an average of 2 implants per month. The average time from referral to implant is approximately 19 months. The greatest number of referrals originated from health districts closest to the implant centre. An examination of patients implanted suggested an imbalance in the uptake of the service amongst the different socio-economic groups.

Outcomes from adult implantation, the first 100 patients.

We present the outcome of implantation in the first 100 adult patients treated under the Midland Cochlear Implant Programme. All patients were post-lingually deaf with profound or total hearing loss. Performance was tested in lip-reading, implant only and combined lip-reading and implant modes using BKB sentences, connected discourse tracking (CDT) and environmental sound recognition. Assessments were made at nine and 18 months post-implant. The dominant aetiologies were idiopathic and meningitis. Meningitis was associated with the greatest numbers of ossified cochleas. Forty-three per cent of cases of partial ossification were identified only at surgery. Four per cent of patients became non-users of their devices, however the majority used their implants for more than 12 hours each day. The mean scores at nine months post-implant, in the implant only mode, were for environmental sound recognition 56.7 per cent, for BKB sentences 46.6 per cent (80 per cent of patients scored above 0 per cent) and for CDT 31.2 words per minute (w.p.m.) (62 per cent scored above zero per cent). In the combined lip reading and implant mode the mean scores, at nine months, were for BKB sentences 81.5 per cent and for CDT 65.8 w.p.m. All results were sustained at 18 months. Patients reported that implantation significantly reduced their hearing handicap. Pre-operative measures of depression were also significantly reduced at nine months post-implant. Results were sustained at 18 months. Post-operative audiological outcomes in the electrical stimulation only mode correlated significantly with length of profound deafness. Results suggest that performance outcome is also related to the number of active electrodes.

Evaluation of cochlear implantation in post-meningitic adults.

Meningitis is an important cause of deafness and in some studies has been associated with poorer outcomes in adult patients following cochlear implantation. Of the first 100 adults implanted under the Midland Cochlear Implant Programme, 28 were deafened as a result of meningitis. We compare our experience with these patients with patients with a non-meningitic aetiology. A degree of cochlear ossification was a more common finding in the meningitic group. In six cases (four meningitis, two non-meningitis) ossification was encountered only during surgery, not being apparent on pre-operative radiology. The average scores achieved on auditory tests by the meningitic group were similar to those achieved by non-meningitic patients. At nine months, using only the implant, users were able to identify 54 per cent of common environmental sounds, achieved an average score of 30 words per minute on connected discourse tracking and identified an average of 42 per cent of words correctly in BKB sentences. Poorer outcomes were more commonly associated with cochlear ossification. In patients with cognitive and neurological sequelae, benefits with the implant were not always apparent in the early months, however, with intensive therapy these patients can obtain measurable sustained benefit from their implant.

Multi-channel cochlear implantation in patients with a post-traumatic sensorineural hearing loss.

There are few accounts of cochlear implantation in adults with post-traumatic sensorineural hearing loss. We report our experience with multichannel implantation in three such patients. Two patients experienced no cognitive or communication deficits as a result of their head injury. At nine months post-implant, compared with our experience of non-head-injured implantees, these patients achieved average or above average scores on audiological performance tests. The third patient presented with cognitive, behavioural and communicative deficits. The level of improvement achieved by this patient, when lip-reading was supplemented with electrical stimulation, in both BKB sentence and connected discourse tracking (CDT) tests was comparable with that of the non-head-injured group. However, his absolute performance at nine months post-implant was well below average. Performance at 18 months on BKB sentences and environmental sound recognition showed little change, and was again well below average, however his score on CDT with lip-reading and electrical stimulation improved considerably and was similar to the average achieved by the non-head-injured group. The major difficulties experienced with this patient were increasing depression and low implant use. Considerably more time was spent in the assessment and rehabilitation of this patient and involved liaison with a number of other agencies. When considering such patients for cochlear implantation it is strongly recommended that these additional requirements are taken into account.

In vitro production of parathyroid hormone-related protein by cholesteatoma and normal skin.

Severe inflammation and infection of the middle ear occasionally results in clinical evidence of bone resorption but with the addition of the cholesteatoma epithelium it becomes inevitable. This study examined production by the cholesteatoma epithelium of a bone resorbing factor, namely parathyroid hormone-related protein (PTH-rP), which would not be expected in inflammatory states alone. PTH-rP was detected in the conditioned medium of primary and secondary cell cultures derived from 12 cholesteatoma biopsies. The levels of PTH-rP were significantly greater than in control cultures of cells derived from normal scalp tissue. Production by the cholesteatoma epithelium may explain the increased incidence of bone resorption in this disease, particularly in cases where inflammation is minimal.

An in vitro growth study on cholesteatoma and normal skin.

The ability of cholesteatoma to grow rapidly within the ear is well recognized. This study aimed to quantify the in vitro growth of cholesteatoma derived cells. Following removal of cholesteatoma explant cultures were established. Cellular outgrowths were subcultured and a colony forming assay performed. Cells were repeatedly passaged every 14 days until senescence was observed. In comparison with cells derived from normal scalp skin, cholesteatoma derived cells demonstrated a lower colony forming efficiency in both primary and secondary subcultures, achieved fewer passages and cell generations in serial culture, and achieved a lower total population expansion. No evidence was found to suggest an intrinsic loss of growth control. It is proposed that the majority of cholesteatoma is composed of cells with a limited capacity for growth. Explant studies suggested that these may be the progeny of more highly proliferative cells situated at the neck of the cholesteatoma sac.

Implications for would healing of patient age and time elapsed since burn injury.

To determine the relationship between growth potential in culture and the age of the patient, skin biopsies were obtained from over 60 patients of varying ages. The relationship between the length of time elapsed since burn injury and growth potential was also examined, using biopsies obtained from patients with burns during their treatment. Keratinocytes were extracted from biopsies and assessed for colony-forming ability by standard methods. Repeated subculture of cells was undertaken to determine the reproductive capacity of cells in vitro. Age had no effect on the colony-forming ability of keratinocytes in primary culture; however age did affect the total number of generations achieved by these cells. The growth potential of keratinocytes from patients with severe burns showed considerable variation according to the amount of time which had elapsed since the injury. This was most apparent around one week post-burn. These results need to be investigated further to understand their clinical implications. The study provides an insight into the influence of age and physiological response on the wound healing process in burn injuries.

Implications for wound healing of patient age and time elapsed since burn injury.

To determine the relationship between growth potential in culture and the age of the patient, skin biopsies were obtained from over 60 patients of varying ages. The relationship between the length of time elapsed since burn injury and growth potential was also examined, using biopsies obtained from patients with burns during their treatment. Keratinocytes were extracted from biopsies and assessed for colony-forming ability by standard methods. Repeated subculture of cells was undertaken to determine the reproductive capacity of cells in vitro. Age had no effect on the colony-forming ability of keratinocytes in primary culture; however age did affect the total number of generations achieved by these cells. The growth potential of keratinocytes from patients with severe burns showed considerable variation according to the amount of time which had elapsed since the injury. This was most apparent around one week post-burn. These results need to be investigated further to understand their clinical implications. The study provides an insight into the influence of age and physiological response on the wound healing process in burn injuries.

Treatment of full skin thickness burn injury using cultured epithelial grafts.

This report presents the experience gained from 26 patients treated with autogenic cultured epithelial grafts (auto-CEG). All auto-CEG were applied to wounds clinically defined as full skin thickness injury. In total 89 separate sites were grafted. The overall estimate of 'take' ranged from 0 to 98 per cent with a mean value of 15 per cent. The highest level of 'take' (43 per cent) was observed when auto-CEG were applied to wounds which had been previously covered with allogenic split-thickness skin grafts. An increased incidence of wound colonization with pathogenic species of bacteria corresponded with a decreased graft 'take'. Ps. aeruginosa and Staph. aureus were found to be present on 32.6 per cent and 60.5 per cent of wound swabs respectively, where 10 per cent or less 'take' of auto-CEG was seen, indicating that bacterial infection is in part responsible for graft failure. However, in 20.9 per cent of such instances, no growth of bacteria was detected, perhaps suggesting that certain wound beds may not present the correct physical environment necessary to support proliferating epithelial cells isolated from their underlying dermal component.

Production of parathyroid-hormone-related protein by cholesteatoma cells in culture.

Specimens of cholesteatoma were removed at surgery from five patients who had evidence of bone resorption. Parathyroid-hormone-related protein (PTHrP) was detected, by radioimmunoassay, in conditioned media from keratinocyte cultures derived from all five samples. Concentrations of PTHrP in conditioned media from secondary cultures were higher for the cholesteatoma cells than for normal keratinocytes from controls matched for age and sex. Thus, production of PTHrP by cholesteatoma may be a contributory factor in the bone destruction commonly associated with this disorder.

The treatment of donor sites with cultured epithelial grafts.

In a significant number of elderly patients, the healing of split skin donor sites can be delayed. The cultured allogenic epithelial graft (CAG) has been reported to heal leg ulcers. The mechanism of action may be to improve the healing environment and thus stimulate the host skin cells. A clinical trial was undertaken to compare the healing rate of the donor sites of elderly patients using CAGs and two commercially available dressings. Compared to Jelonet, CAGs (p = 0.008) and OpSite (p = 0.013) significantly reduced the number of patients with delayed healing. There was no significant difference between CAGs and the occlusive dressing, OpSite.