A smart micro-drill for cochleostomy formation: a comparison of cochlear disturbances with manual drilling and a human trial.

BACKGROUND: Cochleostomy formation is a key stage of the cochlear implantation procedure. Minimizing the trauma sustained by the cochlea during this step is thought to be a critical feature in hearing preservation cochlear implantation. The aim of this paper is firstly, to assess the cochlea disturbances during manual and robotic cochleostomy formation. Secondly, to determine whether the use of a smart micro-drill is feasible during human cochlear implantation. MATERIALS AND METHODS: The disturbances within the cochlea during cochleostomy formation were analysed in a porcine specimen by creating a third window cochleostomy, preserving the underlying endosteal membrane, on the anterior aspect of the basal turn of the cochlea. A laser vibrometer was aimed at this third window, to assess its movement while a traditional cochleostomy was performed. Six cochleostomies were performed in total, three manually and three with a smart micro-drill. The mean and peak membrane movement was calculated for both manual and smart micro-drill arms, to represent the disturbances sustained within cochlea during cochleostomy formation. The smart micro-drill was further used to perform live human robotic cochleostomies on three adult patients who met the National Institute of Health and Clinical Excellence criteria for undergoing cochlear implantation. RESULTS: In the porcine trial, the smart micro-drill preserved the endosteal membrane in all three cases. The velocity of movement of the endosteal membrane during manual cochleostomy is approximately 20 times higher on average and 100 times greater in peak velocity, than for robotic cochleostomy. The robot was safely utilized in theatre in all three cases and successfully created a bony cochleostomy while preserving the underlying endosteal membrane. CONCLUSIONS: Our experiments have revealed that controlling the force of drilling during cochleostomy formation and opening the endosteal membrane with a pick will minimize the trauma sustained by the cochlea by a factor of 20. Additionally, the smart micro-drill can safely perform a bony cochleostomy in humans under operative conditions and preserve the integrity of the underlying endosteal membrane.

Bone-anchored hearing aids for people with bilateral hearing impairment: a systematic review.

BACKGROUND: Bone-anchored hearing aids (BAHAs) are indicated for people with conductive or mixed hearing loss who can benefit from amplification of sound. In resource limited health care systems, it is important that evidence regarding the benefit of BAHAs is critically appraised to aid decision-making. OBJECTIVE OF REVIEW: To assess the clinical effectiveness of BAHAs for people with bilateral hearing impairment. TYPE OF REVIEW: Systematic review. SEARCH STRATEGY: Nineteen electronic resources were searched from inception to November 2009. Additional studies were sought from reference lists, clinical experts and BAHA manufacturers. EVALUATION METHOD: Inclusion criteria were applied by two reviewers independently. Data extraction and quality assessment of full papers were undertaken by one reviewer and checked by a second. Studies were synthesised through narrative review with tabulation of results. RESULTS: Twelve studies were included. Studies suggested audiological benefits of BAHAs when compared with bone-conduction hearing aids or no aiding. A mixed pattern of results was seen when BAHAs were compared to air-conduction hearing aids. Improvements in quality of life with BAHAs were found by a hearing-specific instrument but not generic quality of life measures. Issues such as improvement of discharging ears and length of time the aid can be worn were not adequately addressed by the studies. Studies demonstrated some benefits of bilateral BAHAs. Adverse events data were limited. The quality of the studies was low. CONCLUSIONS: The available evidence is weak. As such, caution is indicated in the interpretation of presently available data. However, based on the available evidence, BAHAs appear to be a reasonable treatment option for people with bilateral conductive or mixed hearing loss. Further research into the benefits of BAHAs, including quality of life, is required to reduce the uncertainty.

Biofilm formation on bone-anchored hearing aids.

OBJECTIVE: To investigate microbiological biofilm contamination of retrieved bone-anchored hearing aids. MATERIALS AND METHODS: Nine failed, retrieved bone-anchored hearing aids and 16 internal screws were examined by scanning electron microscopy. A fixture from a failing implant, which had been removed and disassembled under aseptic conditions, was cultured. Finally, an internal screw from a new, unimplanted fixture was examined by scanning electron microscopy. RESULTS: Debris was seen on the fixture and abutment of all bone-anchored hearing aids, and on the heads of the 16 internal screws. On eight screws, biofilm extended down the shaft to the threads, where it was several micrometres thick. Culture of a failing fixture yielded staphylococcus. The new, unimplanted fixture internal screw showed evidence of scratching and metallic debris on the threads, which may interfere with close fitting of the screw and subsequently facilitate microleakage. CONCLUSION: There may be a link between internal microbial contamination and failure of bone-anchored hearing aids.

Bone-anchored hearing aids (BAHAs) for people who are bilaterally deaf: a systematic review and economic evaluation.

BACKGROUND: A bone-anchored hearing aid (BAHA) consists of a permanent titanium fixture, which is surgically implanted into the skull bone behind the ear, and a small detachable sound processor that clips onto the fixture. BAHAs are suitable for people with conductive or mixed hearing loss who cannot benefit fully from conventional hearing aids. OBJECTIVES: To assess the clinical effectiveness and cost-effectiveness of BAHAs for people who are bilaterally deaf. DATA SOURCES: Nineteen electronic resources, including MEDLINE, EMBASE and The Cochrane Library (inception to November 2009). Additional studies were sought from reference lists and clinical experts. REVIEW METHODS: Inclusion criteria were applied by two reviewers independently. Data extraction and quality assessment were undertaken by one reviewer and checked by a second. Prospective studies of adults or children with bilateral hearing loss were eligible. Comparisons were BAHAs versus conventional hearing aids [air conduction hearing aid (ACHA) or bone conduction hearing aid (BCHA)], unaided hearing and ear surgery; and unilateral versus bilateral BAHAs. Outcomes included hearing measures, validated measures of quality of life (QoL), adverse events and measures of cost-effectiveness. For the review of cost-effectiveness, full economic evaluations were eligible. RESULTS: Twelve studies were included (seven cohort pre-post studies and five cross-sectional 'audiological comparison' studies). No prospective studies comparing BAHAs with ear surgery were identified. Overall quality was rated as weak for all included studies and meta-analysis was not possible due to differences in outcome measures and patient populations. There appeared to be some audiological benefits of BAHAs compared with BCHAs and improvements in speech understanding in noise compared with ACHAs; however, ACHAs may produce better audiological results for other outcomes. The limited evidence reduces certainty. Hearing is improved with BAHAs compared with unaided hearing. Improvements in QoL with BAHAs were identified by a hearing-specific instrument but not generic QoL measures. Studies comparing unilateral with bilateral BAHAs suggested benefits of bilateral BAHAs in many, but not all, situations. Prospective case series reported between 6.1% and 19.4% loss of implants. Most participants experienced no or minor skin reactions. A decision analytic model was developed. Costs and benefits of unilateral BAHAs were estimated over a 10-year time horizon, applying discount rates of 3.5%. The incremental cost per user receiving BAHA, compared with BCHA, was £ 16,409 for children and £ 13,449 for adults. In an exploratory analysis the incremental cost per quality-adjusted life-year (QALY) gained was between £ 55,642 and £ 119,367 for children and between £ 46,628 and £ 100,029 for adults for BAHAs compared with BCHA, depending on the assumed QoL gain and proportion of each modelled cohort using their hearing aid for ≥ 8 or more hours per day. Deterministic sensitivity analysis suggested that the results were highly sensitive to the assumed proportion of people using BCHA for ≥ 8 hours per day, with very high incremental cost-effectiveness ratio values (£ 500,000-1,200,000 per QALY gained) associated with a high proportion of people using BCHA. More acceptable values (£ 15,000-37,000 per QALY gained) were associated with a low proportion of people using BCHA for ≥ 8 hours per day (compared with BAHA). LIMITATIONS: The economic evaluation presented in this report is severely limited by a lack of robust evidence on the outcome of hearing aid provision. This has lead to a more restricted analysis than was originally anticipated (limited to a comparison of BAHA and BCHA). In the absence of useable QoL data, the cost-effectiveness analysis is based on potential utility gains from hearing, that been inferred using a QoL instrument rather than measures reported by hearing aid users themselves. As a result the analysis is regarded as exploratory and the reported results should be interpreted with caution. CONCLUSIONS: Exploratory cost-effectiveness analysis suggests that BAHAs are unlikely to be a cost-effective option where the benefits (in terms of hearing gain and probability of using of alternative aids) are similar for BAHAs and their comparators. The greater the benefit from aided hearing and the greater the difference in the proportion of people using the hearing aid for ≥ 8 hours per day, the more likely BAHAs are to be a cost-effective option. The inclusion of other dimensions of QoL may also increase the likelihood of BAHAs being a cost-effective option. A national audit of BAHAs is needed to provide clarity on the many areas of uncertainty surrounding BAHAs. Further research into the non-audiological benefits of BAHAs, including QoL, is required.

The bone-anchored hearing aid in the rehabilitation of single-sided deafness: experience with 58 patients.

OBJECTIVES: To assess the efficacy of the bone-anchored hearing aid (BAHA) in the rehabilitation of single-sided deafness (SSD). STUDY DESIGN: Retrospective case-control series review. SETTING: Tertiary referral unit. PATIENTS: Fifty-eight consecutive patients that had a bone-anchored hearing aid for single-sided deafness completed outcome questionnaires, building upon earlier audiological assessment of 19 patients. Single-sided deafness controls (n = 49) were mainly acoustic neuroma patients. MAIN OUTCOME MEASUREMENTS: speech discrimination testing in directional noise, speech and spatial qualities of hearing questionnaire and the Glasgow Benefit Inventory (GBI). RESULTS: The mean follow-up time was 28.4 months. Five (13%) of the bone-anchored hearing aid patients were non-users because of lack of benefit. The audiometric testing confirmed that when noise was on the bone-anchored hearing aid side speech perception was reduced but benefited when noise was on the side of the hearing ear. There was no difference between the Speech and Spatial Qualities of Hearing Scores in bone-anchored hearing aid users and controls. In particular there was no difference in the spatial subscores. In the bone-anchored hearing aid users the median Glasgow Benefit Inventory score was 11. If the non-users are included then 13 (22%) patients had no or detrimental (negative) Benefit scores. No or negative benefit scores were more frequent in those deaf for <10 years. In open-field questions, patients felt the bone-anchored hearing aid was most useful in small groups or in 'one-to-one' conversation. CONCLUSIONS: Bone-anchored hearing aid rehabilitation for single-sided deafness is less successful than for other indications, reflected here by relatively low median Glasgow Benefit Inventory scores. There was also no significant difference between controls and bone-anchored hearing aid users in the Speech and Spatial Qualities of Hearing Questionnaire. Patients with a longer duration of deafness report greater subjective benefit than those more recently deafened, perhaps due to differing expectations.

Robotics can lead to a reproducibly high-quality operative result for ear, nose, and throat patients.

The success rates and morbidity of operations on the ear, nose, and throat (ENT) have improved markedly in the last 20-25 years. This has been largely due to improved vision, by microscopes and endoscopes, and has led to a greatly reduced hospital stay. During this time there has been minimal improvement in surgical tools. This paper discusses the need for robotic tools, detailing the clinical constraints that proposed solutions need to adhere to, and presenting a recently trialled micro drilling robot for creating a cochleostomy in the cochlear implant procedure.

The effect of operating time on surgeons' muscular fatigue.

INTRODUCTION: A study was completed to determine if operating has an effect on a surgeon's muscular fatigue. SUBJECTS AND METHODS: Six head and neck surgery consultants, two ENT registrars, 20 normal controls from two tertiary referral centres in the West Midlands participated in the study. Electromyography (EMG) measurements were taken throughout a day of operating and fatigue indices were compared to controls performing desk work. RESULTS: The percentage changes in mean frequency of muscular contractions were examined; there was no significant difference in fatigue levels between consultants and registrars. Operating led to an increase in fatigue in all subjects, compared to no increase in controls performing desk work. It was also found that the brachioradialis muscle is used more than the mid-deltoid muscle and, hence, fatigues at a faster rate. CONCLUSIONS: Surgeons should be aware that their muscular fatigue levels will increase as an operation progresses; therefore, if possible, more complex parts of the operation should be performed as early as possible, or, in the case of a very long operation, a change in surgeon may be necessary.

An autonomous surgical robot for drilling a cochleostomy: preliminary porcine trial.

OBJECTIVE: To produce an autonomous drilling robot capable of performing a bony cochleostomy whilst minimising the damage to the underlying cochlear endosteum. DESIGN: In this laboratory based study, a robotic drill was designed to measure the changes in force and torque experienced by the tool point during the drilling process. This information is used to predict the point of breakthrough and stop the drill prior to damaging the underlying endosteal membrane. SETTING: Aston University. PARTICIPANTS: Five porcine cochleas. MAIN OUTCOMES MEASURES: An assessment was made of whether a successful bony cochleostomy was performed, the integrity of endosteal membrane was then assessed. RESULTS: The autonomous surgical robotic drill successfully performed a bony cochleostomy and stopped without damaging the endosteal membrane in all five cases. CONCLUSIONS: The autonomous surgical robotic drill can perform a cochleostomy whilst minimising the trauma to the endosteal membrane. The system allows information about the state of the drilling process to be derived using force and torque data from the tool point. This information can be used to effectively predict drill breakthrough and implement a control strategy to minimise drill penetration beyond the far surface.

ENT challenges at the small scale.

BACKGROUND: In this paper we consider two relatively frequently performed operations in the field of ear, nose and throat (ENT) surgery and consider how they could be improved by using robotic applications. We consider currently available robots and propose theoretical robotic solutions. METHODS: The application of robotic systems for both cochlear implantation and endoscopic sinus surgery was considered. Currently available robotic systems were reviewed and those with potential use in ENT surgery were identified. For aspects of operations where there is no available technology, hypotheses are presented on how robots could help. RESULTS: Three robotic systems were identified with potential usage in ENT: the Pathfinder neurosurgical robot, the Acrobot knee replacement system and the autonomous smart drill for drilling a cochleostomy. CONCLUSIONS: The challenge for the future of ENT is being able to perform tasks beyond the level of human perception and abilities. The examples presented here demonstrate that microtechnologies could be used to reduce complications, decrease operating time and improve clinical results.

A new method of construction of obturators for nasal septal perforations and evidence of outcomes.

Septal obturators and buttons for nasal septal perforations are often poorly tolerated. We describe a new method of obturator construction using three-dimensional imaging which more closely replicates the true anatomy of the defect. Patients were assessed using a questionnaire relating to how symptoms had changed between having no obturator, a conventional obturator and the new CT obturator. Eight of nine patients had an improvement in total symptom scores comparing old obturators to new CT obturators and this was significant with a P-value of 0.018 using Student's paired t-test. The majority of patients were satisfied with the new obturators and reported an overall improvement of symptoms.

Etanercept, a tumour necrosis factor alpha receptor antagonist, and methotrexate in acute sensorineural hearing loss.

Patients with autoimmune inner-ear disease (AIED) are treated with high doses of steroids in the short term when suffering an acute hearing loss. As a consequence, substances such as methotrexate have been employed in the role of steroid-sparing agents. Additionally, it is known that tumour necrosis factor alpha (TNFalpha) is an important mediator of the inflammatory process, inhibition of which may be of benefit in AIED. This case report illustrates the use of a TNFalpha inhibitor in combination with methotrexate, which is known to be an effective combination in rheumatoid arthritis but has yet to be described for sensorineural hearing loss. We conclude that progressive AIED may respond well to TNFalpha inhibition, whilst more difficult cases, such as this example, could benefit from combining such therapy with methotrexate.

Non-users and limited users of cochlear implants.

This study evaluates the incidence of non-use and limited use of cochlear implants and attempts to identify predictors of such outcome. This involved a retrospective analysis of questionnaires, clinical and audiological data of 423 cochlear implant recipients from the Midland Adult Cochlear Implant Programme and Birmingham Paediatric Cochlear Implant Programme between 1990 and 2000. Of the 172 children in the paediatric programme 5 (2.9%) were non/limited users and of the 251 adults in the adult programme 7 (2.78%) were non/limited users. Thus in total 12 (2.82%) recipients were deemed to be either limited users (0.94%) or non-users (1.89%) of their implants. The mean duration of deafness prior to implantation was around 10 years in both the paediatric and adult groups. In the paediatric group, peer pressure played a prominent role in the non-use of implant. Depression, tinnitus, concomitant neurological problems and non-auditory stimulation seemed to be the predominant reasons in the older age group. The reasons for limited use were cognitive slowing and problems with background noise.

Detection of laryngeal carcinoma and epithelial hyperplastic laryngeal lesions via a rapid-access dysphonia clinic.

Recent government initiatives in the UK have focused on streamlining oncology services by reducing waiting times between urgent referral, assessment and treatment of patients with possible cancer. The performance of the Quick Early Diagnosis Dysphonia Clinic of the Queen Elizabeth Hospital, Birmingham, between May 1997 and April 2001 was reviewed. Of 721 patients reviewed, 123 (17 per cent) had clinically suspicious laryngeal lesions. Thirteen cases of epithelial hyperplastic laryngeal lesions and 27 laryngeal malignancies were diagnosed. There was no statistical link between early cancer detection and assessment within two weeks of referral. However, rapid-access clinics for dysphonia serve an important role in the reassurance and multidisciplinary management of patients with persistent hoarseness. Greater financial commitments are necessary to achieve compliance with objectives for a maximum two-week wait for patients with suspected laryngeal malignancy.

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.

Clinical experience with the Vibrant Soundbridge implant device.

OBJECTIVE: To evaluate the full degree and range of benefits provided by the Vibrant Soundbridge (VSB; Symphonix Devices, Inc., San Jose, CA, U.S.A.) and analyze pre-and postoperative results of audiologic tests. STUDY DESIGN: Single-subject study with each subject serving as his or her own control. SETTING: Multicenter clinical study conducted at 10 centers in Europe. PATIENTS: 47 patients who met the selection criteria for participation in the study. INTERVENTIONS: Implantation of the VSB direct-drive middle ear hearing device. MAIN OUTCOME MEASURES: Average change in unaided thresholds with the patient wearing headphones at each frequency pre-and postsurgery was measured. A mean threshold change less than 5 dB across all frequencies was considered clinically nonsignificant. RESULTS: 47 patients had successful surgery for implantation and fitting with the VSB device. CONCLUSION: The VSB is a new middle ear implant device that can be used safely in the treatment of patients with moderate to severe sensorineural hearing loss.

Adult cochlear implantation: the Birmingham and United Kingdom experiences.

Cochlear implantation has been called a modern miracle and has probably exceeded the expectations of even its most ardent early pioneers. The capabilities of the preprogrammed brain permits patients, within minutes of activation, to appreciate common sounds not heard for many years and within days and weeks to comprehend open-set language without lip reading and even to use the telephone. In the last two decades, cochlear implantation has been widely accepted by the medical community, and rapid developments have been made in the technology and reliability of the devices by the manufacturers.

Osseo-integration in Paget's disease: the bone-anchored hearing aid in the rehabilitation of Pagetic deafness.

The first report of a patient with gross Paget's disease and progressive hearing loss who successfully underwent hearing rehabilitation with an osseo-integrated hearing aid is presented. The otological manifestations of Paget's disease and the principles of osseo-integration are discussed. The use of a bone-anchored hearing aid (BAHA) in selected patients with Paget's disease can provide useful amplification and hearing rehabilitation.