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 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.

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.

Reduction of pentylenetetrazole-induced seizure activity in awake rats by seizure-triggered trigeminal nerve stimulation.

Stimulation of the vagus nerve has become an effective method for desynchronizing the highly coherent neural activity typically associated with epileptic seizures. This technique has been used in several animal models of seizures as well as in humans suffering from epilepsy. However, application of this technique has been limited to unilateral stimulation of the vagus nerve, typically delivered according to a fixed duty cycle, independently of whether ongoing seizure activity is present. Here, we report that stimulation of another cranial nerve, the trigeminal nerve, can also cause cortical and thalamic desynchronization, resulting in a reduction of seizure activity in awake rats. Furthermore, we demonstrate that providing this stimulation only when seizure activity begins results in more effective and safer seizure reduction per second of stimulation than with previous methods. Seizure activity induced by intraperitoneal injection of pentylenetetrazole was recorded from microwire electrodes in the thalamus and cortex of awake rats while the infraorbital branch of the trigeminal nerve was stimulated via a chronically implanted nerve cuff electrode. Continuous unilateral stimulation of the trigeminal nerve reduced electrographic seizure activity by up to 78%, and bilateral trigeminal stimulation was even more effective. Using a device that automatically detects seizure activity in real time on the basis of multichannel field potential signals, we demonstrated that seizure-triggered stimulation was more effective than the stimulation protocol involving a fixed duty cycle, in terms of the percent seizure reduction per second of stimulation. In contrast to vagus nerve stimulation studies, no substantial cardiovascular side effects were observed by unilateral or bilateral stimulation of the trigeminal nerve. These findings suggest that trigeminal nerve stimulation is safe in awake rats and should be evaluated as a therapy for human seizures. Furthermore, the results demonstrate that seizure-triggered trigeminal nerve stimulation is technically feasible and could be further developed, in conjunction with real-time seizure-predicting paradigms, to prevent seizures and reduce exposure to nerve stimulation.

The effect of aluminium coating on elemental signals in X-ray microanalysis.

It has been determined that, in the normal range of aluminium coating thicknesses used to remove charge from non-conducting specimens in the electron microscope, no detectable influence on the elemental signals obtained in X-ray microanalysis is observed. This is in contrast to a previous report (Hopkins et al., J. Electron Microsc. Tech., 18:176-182, 1991) of a reduction in elemental signal with increasing aluminium coating thickness. An explanation of errors in the previous interpretation is provided.

Preparation of aqueous standards for low temperature X-ray microanalysis.

A technique, using Nuclepore polycarbonate membrane filters as a containing medium for very small volumes of ionic standard solutions, to produce homogeneous ice standards is described. The standards are suitable for use in a scanning electron microscope. The relationship between elemental X-ray counts and ionic concentration is found to be linear. The method is rapid and simple. Minimum detectable concentrations are given.

Determination of lipids in infant formula powder by direct extraction methylation of lipids and fatty acid methyl esters (FAME) analysis by gas chromatography.

Fatty acid methyl esters (FAMEs) of pure triglyceride standards, oils, and fat from dry matrixes were formed by transesterification using sodium methoxide in methanol-hexane. FAMEs were produced by direct addition of sodium methoxide-hexane to samples and heating to simultaneously extract and transesterify acyl lipids. FAMEs were quantitated by capillary gas chromatography (GC) over a fatty acid concentration range of 0 to 1.7 mg/mL (r > or = 0.9997). Total fat was calculated as the sum of individual fatty acids expressed as triglyceride equivalents, in accordance with nutrition labeling guidelines. Saturated, polyunsaturated, and monounsaturated fats were calculated as sums of individual free fatty acids. Absolute recoveries determined from individual fatty acids in test samples ranged from 69.7 to 106%. Recoveries (relative to the C13:0 internal standard) for individual fatty acids in test samples ranged from 95 to 106%. Reproducibility was constant at each fatty acid level in the reaction mixture (n = 5, coefficient of variation [CV] < 2%). Absolute recovery determined from the sum of total fatty acids in standard reference material (SRM) 1846 (powdered infant formula) was 96.4%. Analysis of SRM 1846 gave results that agreed closely with the certified fat and fatty acid values. Analysis of commercial infant formula gave results that were comparable to those obtained with AOAC Method 996.01. The direct extraction methylation procedure is rapid, and the transesterification of acyl lipids to form FAMEs is complete within 15 min. Classical saponification and refluxing are not required. This method provides FAMEs free of interferences and easily quantitated by GC or confirmed by GC/mass spectrometry (MS). Unambiguous MS identification of individual FAMEs derived from pure standards, SRM 1846, and powdered infant formula product was obtained.

Zero control reference materials for infant formula methods development.

A zero control reference material (ZRM) for milk and soy-based infant formula was manufactured and characterized. The ZRM was free of retinyl palmitate and all-rac-alpha-tocopheryl acetate. The composition was similar to commercially available infant formula. The ZRM provides a valuable tool to ascertain method performance.

Lipoma of the larynx.

Two cases of intrinsic laryngeal lipoma are added to the twenty-four cases recorded previously. Lipoma may occur anywhere beneath the skin over the entire body. In the larynx these tumours lie rather deep and it is therefore important to obtain a deep tissue biopsy. It is possible to remove a substantial part of the swelling endoscopically and to relieve the patient's symptoms. We feel that lipoma of the larynx may be more common than has hitherto been reported in the literature.

Distribution of ear drops in normal ears.

Ear drops are prescribed widely with little thought for the distribution inside the ear canal. This study compares the distribution of water and oil based drops. The results indicate that, under the test conditions, the penetration of ear drops is extremely variable. Water provided the greatest overall coverage, while the most viscous drops fared worst. It is suggested that in diseased ears even poorer penetration may result, which may explain the lack of response in some circumstances.

Distribution of ear drops using a non-aerosol spray delivery system.

The distribution of ear drops in normal ears is variable. A new product Otomize (Stafford-Miller) containing dexamethasone and neomycin has a non-aerosol spray mist delivery system. This has been applied to normal ears and found to be superior in its distribution to generally available ear drops previously assessed.

Unilateral nasal obstruction: an unusual presentation of a complication of nasotracheal intubation.

Partial avulsion of the middle turbinate is an unusual complication of nasotracheal intubation while minor nasal mucosal trauma is not uncommon. Nasal turbinate avulsion often presents with persistent epistaxis but in the case reported, unilateral nasal obstruction with minimal epistaxis was the presenting feature. Unilateral nasal obstruction following nasotracheal intubation should raise suspicion of significant disruption of the intranasal architecture.

Cutaneous nasal sarcoidosis--treatment by excision and split-skin grafting.

We report two cases of nasal sarcoidosis which are both treated by excision and split-skin graft and yield good results after one year and three years' follow-up.

Localized middle ear effusions: three unusual acute cases in adults.

Three cases of acute, non-suppurative otitis media in adults are described. They are unusual in that the effusion was confined to the upper middle ear, whilst the lower middle ear was aerated. The aetiology of such localized effusions, is probably related to the anatomy of the middle ear compartments, the mucosal folds forming them and the apertures allowing communication between them. The compartments are relatively constant and are a result of the embryological development of the middle ear. The localization of these effusions, demonstrates the segmental anatomy of the middle ear.

Staging carcinoma: its value in cancer of the larynx.

Three thousand four hundred and forty-five cases of cancer of the larynx were examined and 3,235 assigned to their TNM group. While good correlation with prognosis could be seen, the value of the detailed subsite (as opposed to the main laryngeal regions) was limited to defining T1a and T1b and aiding that of T2. T status gives some indication of prognosis, but the N status is of almost overriding importance.

Neonatal septal deviations.

In a review of 1000 consecutive neonates of all races, nasal septal deformity was identified in 29, an incident of 2.9%; significantly fewer cases were found in negroid babies (0.1 greater than P greater than 0.05). Ten cases (35%) underwent manipulation of the deviated septum. Six-monthly review revealed that symptoms associated with the septal deformity are rare. In 7 (44%) of the 16 cases not manipulated, the septum straightened spontaneously during the first few months of life. The appearance of the deviation is not of a dislocation of the caudal edge of the cartilage but a smooth concavity. In vitro compression of the neonatal nasal cavity reproduced this C-shaped deformity, but only temporarily. Histological serial sections of 6 postmortem nasal cavities showed that the high laminae of the vomer prevent any caudal dislocation of the septal cartilage.

Surgical approach to the parotid gland.

The key to surgical treatment of the parotid gland is adequate exposure and careful identification and protection of the facial nerve. The superficial and deep lobes of the gland can be removed from external approaches with little or no damage to the facial nerve if a careful and thoughtful surgical technique is employed.

Initial experience of a rapid-insertion bone-anchored hearing system: series of 20 consecutive implants.

Objective: The loading of bone-anchored hearing system sound processors usually occurs two to three months after surgical implant. This study examined a new bone-anchored hearing system coupling mechanism that permits loading at two weeks post-implantation without compromising osseointegration. Methods: Twenty implants were implanted into 15 patients. The interval between operation and time of processor loading was recorded, along with the cause of any delay and any late complications. Results: Two patients were fitted with implants at seven and nine weeks. The delay was a result of administrative errors; the patients reported no skin problems. Of the remaining 17 implants, 8 processors were fitted at 2 weeks, 1 at 3 weeks, 4 at 4 weeks, 3 at 7 weeks and 1 at 8 weeks. For those nine implants fitted later than two weeks, the delay was because of incomplete skin healing. Conclusion: The Oticon Medical Xpress system allowed processor loading at two weeks post-operatively, providing skin healing was adequate. Early loading occurred in approximately half of the patients. All patients were fitted within the two to three months traditionally allowed. Prolonged skin healing time was the main reason for the delayed fitting of sound processors.

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.

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.