Preclinical Validation of a Novel Device Designed to Reduce Biofilms on Percutaneous Osseointegrated Abutments.

AIM: To assess the efficacy of a prototype cleaning device in removing biofilm from skin-penetrating abutments. BACKGROUND: Adverse skin reactions around percutaneous osseointegrated implants have been linked to poor hygiene and infection. A cleaning device made from open-cell polyfoam has been developed to facilitate manual cleaning of abutments by the patient. METHODS: Serratia biofilm was grown on clean and sterile conical bone-anchored hearing system abutments including both pre-2007 (straight sided) and post-2007 (conical-sided) designs. Eighteen were photographed and then subjected to cleaning using a toothbrush or the cleaning device soaked in water or a proprietary mouthwash. Biofilm on a further group of 10 conical abutments was recorded using a scanning electron microscope before and after cleaning with the test device soaked in water. Quantitative analysis of the efficiency of the cleaning was made using image analysis. RESULTS: Removal of biofilm using a dry or wet toothbrush was not as effective as cleaning with the device. In 10 cases subjected to image analysis, approximately 90% of the biofilm was removed from the top third of the abutments, 85% from the middle third, and 48% from the basal third. CONCLUSION: The cleaning device is effective in removing most biofilm from the test abutments and represents a significant improvement in comparison with traditional methods such as a toothbrush.

A ten-year review of soft tissue reactions around percutaneous titanium implants for auricular prosthesis.

OBJECTIVES/HYPOTHESIS: Soft tissue reactions around abutments are the most common complications of percutaneous osseointegrated implants. The main objective of this study was to review our series of osseointegrated implants, evaluate the degree of adverse skin reactions around the auricular abutments, and compare with skin reactions in the pediatric bone-anchored hearing aid (BAHA) population. The reason for comparing these two groups was the difference in abutment shape and position in skin with different characteristics. STUDY DESIGN: A retrospective case analysis of 131 patient notes. METHODS: We retrospectively studied 131 pediatric and adult patients who underwent an osseointegrated auricular prosthesis over a 10-year period (1997-2007). RESULTS: There were 95 adults and 36 children who had been implanted and fitted with an auricular prosthesis during the 10-year study period. All patients were followed up postoperatively for a 2-year minimum up to a 14-year maximum follow-up. Thirteen (13/36, 36%) children and seven adults (7/95, 7%) had a skin reaction around the ear prosthesis. CONCLUSIONS: The literature review has supported our study results and has shown that children have higher skin reactions in both BAHA and auricular prostheses than adults. Adverse skin reactions in the pediatric auricular group were significantly lower that the pediatric BAHA group. LEVEL OF EVIDENCE: 4

Mechatronic feasibility of minimally invasive, atraumatic cochleostomy.

Robotic assistance in the context of lateral skull base surgery, particularly during cochlear implantation procedures, has been the subject of considerable research over the last decade. The use of robotics during these procedures has the potential to provide significant benefits to the patient by reducing invasiveness when gaining access to the cochlea, as well as reducing intracochlear trauma when performing a cochleostomy. Presented herein is preliminary work on the combination of two robotic systems for reducing invasiveness and trauma in cochlear implantation procedures. A robotic system for minimally invasive inner ear access was combined with a smart drilling tool for robust and safe cochleostomy; evaluation was completed on a single human cadaver specimen. Access to the middle ear was successfully achieved through the facial recess without damage to surrounding anatomical structures; cochleostomy was completed at the planned position with the endosteum remaining intact after drilling as confirmed by microscope evaluation.

Feasibility study of a hand guided robotic drill for cochleostomy.

The concept of a hand guided robotic drill has been inspired by an automated, arm supported robotic drill recently applied in clinical practice to produce cochleostomies without penetrating the endosteum ready for inserting cochlear electrodes. The smart tactile sensing scheme within the drill enables precise control of the state of interaction between tissues and tools in real-time. This paper reports development studies of the hand guided robotic drill where the same consistent outcomes, augmentation of surgeon control and skill, and similar reduction of induced disturbances on the hearing organ are achieved. The device operates with differing presentation of tissues resulting from variation in anatomy and demonstrates the ability to control or avoid penetration of tissue layers as required and to respond to intended rather than involuntary motion of the surgeon operator. The advantage of hand guided over an arm supported system is that it offers flexibility in adjusting the drilling trajectory. This can be important to initiate cutting on a hard convex tissue surface without slipping and then to proceed on the desired trajectory after cutting has commenced. The results for trials on phantoms show that drill unit compliance is an important factor in the design.

Perioperative considerations for children undergoing bone anchored hearing device surgery: an observational study.

The objective of the study was to identify important factors in the perioperative management of children undergoing bone anchored hearing device (BAHD) surgery in a paediatric tertiary centre. We also aim to compare current practice and identify any changes in practice with the previous study carried out in the same paediatric tertiary centre in 2000. Children undergoing BAHD surgery between January 2008 and January 2011 were identified on a departmental database. A retrospective case note review was performed and compared with data collected prior to 2000. In the study period, 194 children were identified to have had BAHD surgery. 134 case notes were available for analysis and of these children, 353 anaesthetics were identified. 45.5% of the children had a recognised syndrome or dysmorphism and 17% had a congenital cardiac anomaly. 16% of the children were classified as a grade 3 or 4 laryngoscopy, but 83.3% were managed with a laryngeal mask. 11.9% of the children had an intraoperative complication and 4.8% a postoperative complication. 88.4% of children were managed as day cases. Compared with the previous study in 2000, there was a smaller proportion of syndromic or dysmorphic children and a larger proportion of children were managed with a laryngeal mask. As BAHD surgery has become more common and as its indications have expanded, the perioperative management has evolved. The proportion of children with congenital heart disease has remained constant, but there has been a marked reduction in the number of children with syndromes involving the head and neck. We have found that even in complex craniofacial cases, the laryngeal mask is increasingly being used with good results. However, advanced paediatric airway experience was still required in a small number of cases, heightening the awareness that specialised paediatric support services are necessary for a comprehensive BAHD programme.

Comparison on intracochlear disturbances between drilling a manual and robotic cochleostomy.

During cochlear implantation, hearing preservation is a concern. Minimizing disturbances to the cochlea and protection of the underlying endosteal membrane during the formation of a cochleostomy are considered important factors. The robotic micro-drill system tested in this article is the first example of an autonomous surgical drill successfully producing a cochleostomy, which keeps the underlying endosteal membrane intact. This study compares induced disturbances within the cochlea during formation of cochleostomy using the robotic micro-drill with that of conventional manual drilling. The disturbance of the endosteal membrane is measured using a Microscope Scanning Vibrometer at a third window, produced in the cochlea. Results show that the highest velocity amplitude measured was associated with manual drilling technique. The robotic micro-drill technique produced only about 1% of the peak velocity amplitude seen in manual drilling and exhibited much more uniform behaviour, while keeping the underlying membrane intact. The technique applied when using the robotic drill could be a major step in reducing the trauma to the cochlea, by reducing disturbance levels.

Robustness analysis of a smart surgical drill for cochleostomy.

BACKGROUND: There is a need for sensor-guided robotic devices that discriminate working conditions and media, and control interaction of tool-points with respect to tissues. At the micro-surgical scale the need is to control exact penetration through flexible tissues and to control relative motion with respect to moving or deforming tissue targets and interfaces. METHODS: This paper describes a smart surgical drill that is able to control interaction with respect to the flexing tissue to avoid penetration or to control the extent of protrusion with respect to the position of the flexible tissue interface under drilling. The sensing scheme used is able to discriminate between the variations in types of conditions posed in the drilling environment. RESULTS: The fully autonomous system is able to respond to tissue type, behaviour and deflection in real time. The system is robust in terms of different drilling angle, thickness, stiffness, and disturbances encountered. Also it is intuitive to use, efficient to set up and uses standard drill bits. CONCLUSIONS: The smart drill has been used to prepare cochleostomies in theatre and was used to remove bone tissue leaving the endosteal membrane intact. This has enabled preservation of sterility and the drilling debris to be removed prior to insertion of the electrode. Results presented in this paper suggest that the robotic smart drill is tolerant and robust on various angled drilling trajectories with respect to tissues, tissue thickness, environmental disturbances, and has been used within the operating theatre.

Quality-of-life outcomes after bone-anchored hearing device surgery in children with single-sided sensorineural deafness.

OBJECTIVE: To report our experience in a series of children with single-sided sensorineural deafness where a bone-anchored hearing device (BAHD) was used for auditory rehabilitation. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral centre. PATIENTS: Eight children (4 boys and 4 girls) who had BAHD surgery for single-sided sensorineural deafness between 2007 and 2010. INTERVENTION(S): Bone-anchored hearing device was used for auditory rehabilitation. MAIN OUTCOME MEASURE(S): Glasgow Children's Benefit Inventory (GCBI), Single-sided Deafness (SSD) Questionnaire and change in health benefit scores (visual analogue scale). RESULTS: All but one of the children showed a positive GCBI score; the child that reported a negative score was because of low self confidence and self-esteem issues secondary to bullying at school. The results of the SSD questionnaire were generally positive with a mean satisfaction score of the BAHD as 9/10. All the children had an improvement in heath benefit. CONCLUSION: Our findings add further evidence to support patient perceived benefit of a BAHD in single sided sensorineural deafness in the paediatric population.

Cost-effectiveness analysis of the bone-anchored hearing device.

OBJECTIVE: To establish the cost-effectiveness of a bone-anchored hearing device (BAHD). To date, there has not been any formal economic analysis of this treatment. STUDY DESIGN: A prospective cohort case-control analysis. SETTING: Tertiary referral center, university hospital. PATIENTS: Between April 2007 and June 2008, all adult patients undergoing their first BAHD were contacted and invited to take part in this study. Data of 70 patients were completed during the study period and were analyzed. INTERVENTIONS: A health utility measure was made before and after the insertion of a BAHD to estimate the utility gain associated with this intervention. MAIN OUTCOME MEASURES: The cost and quality-adjusted life year (QALY) gain for each patient was established, and an incremental cost-effectiveness ratio (ICER) was calculated. RESULTS: The results of our analysis are that, compared with current standard care, the BAHD has an ICER of £17,610 (US $26,415) per QALY gained. The National Institute for Health and Clinical Excellence will endorse a health intervention as cost-effective if the ICER is below £20,000 to £30,000 per QALY (US $30,000-45,000). CONCLUSION: This technology is likely to be cost-effective at the current thresholds used by National Institute for Health and Clinical Excellence. Therefore, this study suggests the BAHD may be a cost-effective method of auditory rehabilitation.

The 8.5mm abutment in children: the Birmingham bone-anchored hearing aid program experience.

OBJECTIVE: To the best of our knowledge, the use of the 8.5-mm abutment and its long-term outcome in the pediatric population has not been reported in the medical literature. We describe our experience with the use of the 8.5-mm abutment in a series of 16 children who have required a long abutment. STUDY DESIGN: Retrospective case series review. SETTING: Tertiary hospital. PATIENTS: Patients younger than 16 years who had an 8.5-mm bone-anchored hearing aid abutment fitted. INTERVENTION: Use of an 8.5-mm bone-anchored hearing aid abutment. MAIN OUTCOME MEASURES: Indications and complications with using the 8.5-mm abutment. RESULTS: We have used the longer abutment on both 3- and 4-mm fixtures. We have found the need to use it particularly around the time of puberty when we observed soft tissue problems develop. Follow-up after insertion of the long abutment ranged from 6 months to 6 years. There was 1 fixture extrusion 2 years after a long abutment had been fitted. CONCLUSION: Overall, we have found the long abutment to be useful in a selected pediatric population.

The use of a bone-anchored hearing aid (Baha) in children with severe behavioural problems--the Birmingham Baha programme experience.

OBJECTIVE: A trial of a bone conductor is traditionally used to determine whether a bone-anchored hearing aid (Baha) will be beneficial to a child. However there is a subgroup of children where a Baha assessment is not possible due to severe behavioural/mental/sensory disorders. We describe our experience in a small series of such children. METHOD: Retrospective case series review of four children at the severe end of the spectrum of behavioural difficulties who underwent Baha implantation where no formal preoperative hearing aid assessment was possible. The Glasgow Children's Benefit Inventory and a visual analogue scale assessing health status were used to determine the benefit of Baha implantation in this group. RESULTS: There was no surgical morbidity in this group although a more intensive postoperative follow up was required. All four children wore their hearing aids at least 8h a day. Parents reported a positive impact of the Baha on the behaviour and mood of their children. The Baha showed a positive benefit when assessed using the Glasgow Children's Benefit Inventory and showed a positive change in health status. CONCLUSIONS: We feel that our early experience with Baha in children with severe behavioural difficulties has been positive to date. Multidisciplinary teams should not dismiss these children even if a trial of a bone conductor is not possible. We feel that the bone-anchored hearing aid has been successful in our cases because the children do not physically feel the presence of the hearing aid.

Fluid exudates from inflamed bone-anchored hearing aids demonstrate elevated levels of cytokines and biomarkers of tissue and bone metabolism.

OBJECTIVE: The purpose of the current study was to determine the presence of biomarkers of tissue and bone metabolism and 10 cytokines within the fluid exudate from around bone anchored hearing aids (BAHAs), with a view to understanding the mechanisms of peri-BAHA inflammation. STUDY DESIGN: Fluid exudate from around BAHAs was collected from volunteers (n = 10) with inflammation and controls (n = 10) without inflammation around the BAHA. SETTING: Studies of periodontitis and dental peri-implantitis have demonstrated that fluid exudate, arising from the hard tissue-soft tissue junction, is increased during disease; this fluid contains biomarkers of tissue metabolism, bone metabolism and inflammation. PATIENTS: Volunteers were recruited from the Queen Elizabeth Hospital, Birmingham, UK and New Cross Hospital, Wolverhampton, UK. INTERVENTIONS: This was an observational study and no interventions were carried out as part of the study. MAIN OUTCOME MEASURE: Biomarkers of tissue metabolism (MMP9, TIMP1 and 2), bone metabolism (RANKL and OPG) and cytokines (GM-CSF, interferon (IFN)-*, IL-1A, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10 and TNF>) were measured in the fluid samples by Luminex multianalyte assay. RESULTS: Volumes of fluid exudate were significantly higher (p < 0.05) at sites of inflammation than from un-inflamed tissues surrounding BAHAs. IL-1*, IL-6, IL-8, TNF*, MMP9, TIMP1 and 2 were found in both inflamed and un-inflamed samples and levels were significantly higher in samples from inflamed sites. RANKL, IFN*, IL-2, IL-4, and GM-CSF were detected only at inflamed sites whereas OPG, IL-5 and IL-10 were not detected in any samples. CONCLUSION: These data demonstrate that peri-BAHA tissues showing clinical signs of inflammation are associated with increased fluid exudate, which contains elevated levels of key biomarkers of inflammation and a biomarker profile that is consistent with increased tissue and bone remodeling around BAHAs.

Bilateral Bone-anchored Hearing Aid: impact on quality of life measured with the Glasgow Benefit Inventory.

OBJECTIVE: To investigate whether the fitting of bilateral Bone-anchored Hearing Aid (BAHA) would result in any additional improvement in patients' quality of life (QOL) over and above what we would experience from the fitting of a single-sided BAHA. STUDY DESIGN: Retrospective, anonymized, cross-sectional postal survey using the Glasgow Benefit Inventory (GBI). SETTING: Tertiary referral center. PATIENTS: All 93 adult patients who had been using bilateral BAHA for more than 6 months. INTERVENTION(S): Hearing rehabilitation using bilateral BAHA. MAIN OUTCOME MEASURE(S): These include the GBI benefit scores across the following domains: "overall benefit," "general health benefit," "physical health benefit," and "social benefit." Comparison of GBI scores against other otological interventions including single-sided BAHA. RESULTS: Response rate was 76%. Ninety-two percent of patients reported improvement in QOL. Positive QOL improvement scores were reported across all domains. Overall GBI benefit score was +ve 38. This is higher than the benefit scores reported by patients with single-sided BAHA, although this may not be statistically significant. CONCLUSION: After fitting the second BAHA, patients may report additional improvement in their QOL (of a smaller magnitude) over and above the initial improvement in their QOL after fitting of their first BAHA. In fact, the overall benefit score for bilateral BAHA seem to be close to that for cochlear implantation.

Bone-Anchored Hearing Aid: patient satisfaction with the Cordelle device.

OBJECTIVE: To assess patient satisfaction with the Bone-Anchored Hearing Aid (BAHA) Cordelle device and to identify any user- and device-related issues. STUDY DESIGN: Retrospective, anonymized, cross-sectional postal survey using the Entific Medical Systems questionnaire. SETTING: Tertiary referral center. PATIENTS: Fifty adult patients who had been using the BAHA Cordelle for more than 6 months. INTERVENTION: Hearing rehabilitation using BAHA Cordelle. MAIN OUTCOME MEASURES: Patients' satisfaction with the BAHA Cordelle in a variety of real-life hearing scenarios, their actual use of the device, and other issues with the device. RESULTS: Response rate was 66%. Responders were happy with their Cordelle in quiet situations and 1-to-1 conversations but less so in noisy or in group situations.However, approximately 80% of Cordelle users will use their device everyday for more than 8 h/d, and the overall satisfaction level is high. Compared with ear-level BAHA patients, Cordelle users are older and have mixed hearing loss with poorer sensorineural reserve, making hearing rehabilitation more challenging. CONCLUSION: The findings of this study support the use of the BAHA Cordelle as a viable, safe, low-morbidity hearing rehabilitation option in patients with mixed hearing loss with poor sensorineural reserve. Patients should be counseled appropriately to help manage their expectations.

Experience with the longer (8.5 mm) abutment for Bone-Anchored Hearing Aid.

BACKGROUND: Use of the longer (8.5 mm) abutment for a Bone-Anchored Hearing Aid has been helpful for a certain group of patients. The most common reason for its use is soft tissue problems with tissue overgrowth interfering with device function. The longer abutment has been used in our institution, a tertiary referral center, on a named patient basis since 2002, and more than 100 patients have received it. OBJECTIVES: This paper will review this subgroup of patients and describe their demographics. Comorbidity, smoking history, graft failure, infection, and index of deprivation will be looked at as contributing factors for this group with soft tissue problems. PATIENTS: We identified 111 patients who had longer abutments ordered for them, and a retrospective case review was performed. RESULTS: Eighty-one patients required soft tissue reduction surgery because of overgrowth, and all but one (80/81 [98.8%]) of these patients required no further surgery after having their 5.5-mm abutment changed to the 8.5-mm version. One patient underwent further surgery 10 months after the longer abutment was inserted but has been problem-free for 16 months since then. Length of follow-up ranged from 6 months to 5 years after converting to the longer abutment. CONCLUSION: We have found the longer abutment to be very successful for the small proportion of patients with troublesome soft tissue overgrowth. We would advocate its use when topical management and surgical intervention have failed to control the skin reaction.

The birmingham pediatric bone-anchored hearing aid program: a 15-year experience.

OBJECTIVE: To evaluate the complication rates and outcomes of children who were fitted with a bone-anchored hearing aid (BAHA) on the Birmingham BAHA program. STUDY DESIGN: Retrospective case analysis of clinical records of all children implanted at Birmingham Children's Hospital since the beginning of the program in 1992 until February 2007. PATIENTS: A total of 182 children younger than 16 years old fitted with a BAHA. Of these children, 107 had a significant medical history. RESULTS: Surgery was performed as a 2-stage procedure in 174 children. The healing time was between 3 and 4 months in 112 (64%) cases. Single-stage surgery was performed in 8 cases. Implant failures were 14% of 230 loaded fixtures (32 fixtures lost in total). Multiple-fixture failures (18 fixture failures) occurred in 7 patients. Adverse skin reactions appeared in 34 (17%) patients during a 15-year follow-up period. Revision surgery was undertaken in 14 (8%) cases because of skin overgrowth around the abutment. Five of these cases required multiple surgical skin reductions. CONCLUSION: The Birmingham Program has a high proportion of syndromic patients with complex medical problems. The fixture failure rate was found to be 14%. This included the multiple-fixture failures in children younger than 3 years old. There was 1 serious complication. The BAHA is a reliable and effective treatment for selected patients. Our program currently has 97% of its children wearing their BAHA on a daily basis with continuing audiologic benefit.

Quality of life in children fitted with a bone-anchored hearing aid.

OBJECTIVES: To evaluate the self-rated quality of life and benefits associated with the use of a Bone-Anchored Hearing Aid (BAHA). To assess any change in health status after a BAHA. STUDY DESIGN: This was a retrospective postal questionnaire study. The Glasgow Children's Benefit Inventory was the validated tool used.Children with a BAHA on the Birmingham pediatric Bone-Anchored Hearing Aid Programme from February 1992 to February 2007 were included. PATIENTS: One hundred fifteen children were sent a postal questionnaire. Eighty-four were returned, giving a response rate of 73%. All children had worn their BAHA for more than 6 months. Children with an implant-retained auricular prosthesis were excluded from the study, as were children who were older than 16 years at the time of the questionnaire. Patients with bilateral BAHA were advised to answer the questionnaire with reference to their first BAHA. RESULTS: The BAHA was a success in the pediatric population. All 84 children reported a positive benefit with their BAHA. The median benefit score was +54. No child demonstrated deterioration in health status after their BAHA. CONCLUSION: The use of a BAHA significantly enhanced general well-being, improved patient state of health (quality of life), and finally, was considered a success by patients and their families. This study demonstrates a significant benefit from BAHA as measured by the Glasgow Children's Benefit Inventory.

The role of bone anchored hearing aids in children with Down syndrome.

OBJECTIVES: To evaluate complication rates and outcomes of children with Down syndrome fitted with a Bone Anchored Hearing Aid (Baha). To evaluate whether the Bone Anchored Hearing Aid is a successful form of aural rehabilitation in children with Down syndrome from a patients' perspective. STUDY DESIGN: Retrospective case analysis and postal questionnaire study. SETTING: The Birmingham Children's Hospital, UK. METHODS: A total of 15 children were fitted with a Baha between February 1992 and February 2007. The age range was 2-15 years. A postal questionnaire was sent to each family. The Glasgow Children's Benefit Inventory (GCBI) was used in this study. OUTCOME MEASURES: Implantation results, skin reactions and other complications were recorded. Quality of life after receiving a Baha was assessed with the GCBI. RESULTS: All 15 patients are using their Baha 7 days a week for more than 8h a day after a follow-up of 14 months with continuing audiological benefit. No fixtures were lost, and skin problems were encountered in 3 (20%). Regarding quality of life, all 15 patients had improved social and physical functioning as a result of better hearing. CONCLUSIONS: Baha has an important role in the overall management of individuals with Down syndrome after conventional hearing aids and/or ventilation tubes have been considered or already failed. This study has shown a 20% rate of soft tissue reaction and there were no fixture losses in this group. No significant increase in complication rates was identified in children with Down syndrome. Finally, there was a significantly improved quality of life in children with Down syndrome after receiving their Baha. There was a high patient/carer satisfaction with Baha. Two of our series had bilateral two stage fixture procedures without any complications. More consideration should be given to bilateral bone anchored hearing aids in this group.

A new retractor for cochlear implantation.

In cochlear implantation and other major ear surgeries a post auricular incision is often used. Following this, fascia, muscle and fat is divided, and then a periosteal flap is raised. This creates different tissue planes which need to be held back and protected from the surgeon and the drill. We present a new device which provides excellent retraction for this procedure, does not put undue pressure on the pinna, while at the same time it allowing the surgeon an unobstructed view.

Unexpected exit of a cochlear implant electrode through the wall of the basal turn of the cochlea - a report on two patients.

We describe the unusual complication of the cochlear implant electrode eroding through the lateral bony wall of the cochlear basal turn in 2 different patients. This complication, occurring during life, has not been previously described in the literature. Radiological investigations were vital in making this diagnosis. We also discuss the likely pathophysiology behind this complication.