Patient, Procedure, People (PPP): recognising and responding to intraoperative critical events.

Intraoperative critical events are rarely experienced by individual surgeons but are commonly experienced at a workforce level. Finding unfamiliar or unexpected pathology, anatomy, haemorrhage or an iatrogenic organ or structure injury cannot be completely eliminated in the complex surgical environment. It is vital that an appropriate, safe response to these infrequent events takes place to prevent possible further harm to patients. This paper introduces 'Patient, Procedure, People', a tool adapted from aviation threat and error management (TEM) training. It allows surgical teams to improve situational awareness (SA), communicate effectively, flatten team hierarchy gradients and improve decision-making before responding to critical events. We review factors contributing to poor decision-making, with resulting errors. These include loss of SA (tunnel vision), acute stress reactions (fight-flight or freeze-hide) and limbic hijacking (surprise and startle events). Events may cause workload to increase beyond cognitive capacity, further exacerbating the situation. After completing initial actions to achieve a temporary 'place of safety', surgical teams may use the tool to effectively manage threat or mitigate error. Aviation is a high-reliability organisation that has pioneered human factors research and training. Airline pilots undergo regular simulated emergencies assessment, including mandatory human factors assessment. Although the complexities of the operating theatre do not currently lend themselves to high-fidelity simulation as in aviation, valuable transferrable lessons can be learnt from aviation's approach to TEM.

How safe is diathermy in patients with cochlear implants?

INTRODUCTION: Cochlear implants are surgically inserted electrical devices that enable severely or profoundly deaf individuals to interpret sounds from their environment and communicate more effectively. As a result of their electrical nature, they are susceptible to electromagnetic interference and can be damaged by excessive electrical energy. Surgical diathermy is one source of such potentially damaging energy. The British Cochlear Implant Group guidelines advise that monopolar diathermy should not be used in the head and neck region in patients with cochlear implants and that bipolar diathermy should not be used within 2cm of the implant (http://www.bcig.org.uk/site/public/current/safety.htm). METHODS: A questionnaire was provided to 36 surgeons working in different specialties in the head and neck region, inquiring as to their knowledge of the safety considerations when using diathermy in cochlear implant patients. Thirty-five surgeons provided responses. RESULTS: Overall, 77% of the respondents were unaware of the existence of published guidelines. Even when given an option to seek advice, 11% erroneously felt it was safe to use monopolar diathermy above the clavicles with a cochlear implant in situ and 49% felt that there was no restriction on the use of bipolar diathermy. CONCLUSIONS: There is a significant deficit in the knowledge of safe operating practice in the rapidly expanding population of patients with cochlear implants which threatens patient safety. Through this publication we aim to increase awareness of these guidelines among members of the surgical community and this paper is intended to act as a point of reference to link through to the published safety guidelines.

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.

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.

A case of cranial fasciitis masquerading as acute mastoiditis.

OBJECTIVE: We report a case of infection against a background of pre-existing cranial fasciitis. METHOD: Case report and review of world literature on cranial fasciitis. RESULTS: Cranial fasciitis of childhood is a benign condition and a rare variant of nodular fasciitis. We present the case of a 10-week-old infant with symptoms and signs consistent with a subperiosteal abscess complicating acute mastoiditis. Subsequent findings showed this to be an infection against a background of pre-existing cranial fasciitis. CONCLUSION: To our knowledge, this is the first such reported case in the literature. Knowledge of the distinctive histopathological features, coupled with an awareness of the condition, are crucial to establishing a definitive diagnosis of cranial fasciitis and, in turn, to instituting appropriate management. The aetiopathogenesis of the condition remains unclear.

Severe factor V deficiency presenting with intracranial haemorrhage during gestation.

We present a case of intracranial haemorrhage detected by ultrasound at 36 weeks gestation in a foetus who was ultimately diagnosed with severe factor V deficiency. An abnormality of the foetal heart rate, auscultated at a routine antenatal visit, prompted an investigation that led to an ultrasound examination and detection of an intracranial haemorrhage and low amniotic fluid volume. An intrauterine foetal demise was averted. The clinical scenario in this case raises the issue of how often a stillbirth with intracranial haemorrhage may result from unrecognized factor deficiency.

The preauricular sinus: A review of its aetiology, clinical presentation and management.

The preauricular sinus is a not uncommon finding in the paediatric population. Recent reports have added to our knowledge of this benign malformation. We review the current literature with respect to the aetiology of the condition, its clinical features, and associations with other congenital malformations. In those patients in whom a preauricular sinus is identified, we recommend associated congenital anomalies be sought. In selected cases, a renal ultrasound scan may be appropriate. Where no associated abnormalities are identified, and where the preauricular sinus is asymptomatic, there is consensus opinion that no further action is indicated. In the acute phase of infection, treatment comprises administration of appropriate antibiotics, and incision and drainage of an abscess if present. In the symptomatic preauricular sinus exhibiting recurrent or persistent infection, opinion regarding optimal management varies. Latest evidence suggests definitive surgical treatment offering the most favourable outcome is by wide local excision of the sinus, as opposed to the previously preferred technique of simple sinectomy. Magnification employed during surgery, and opening, and following from the inside as well as outside, branching tracts of the sinus may further minimise the risk of recurrence.

An experimental investigation of the resolution of tympanometry for micro-perforations of the tympanic membrane.

Tympanometry is well established as a useful tool in the field of otological diagnosis. There have been sporadic reports, however, of bizarre tympanograms in the presence of small perforations of the tympanic membrane. A model of the outer and middle ears was fabricated which was able to produce normal and pathological tympanograms. This model was used to investigate tympanometry in the presence of microperforations. A hypothesis for the mechanism of generation of sawtooth tympanograms in the presence of micro-perforations is postulated.

Large-angle electro-optic laser scanner on LiTaO(3) fabricated by in situ monitoring of ferroelectric-domain micropatterning.

We report on a horn-shaped electro-optic scanner based on a ferroelectric LiTaO(3) wafer that is capable of scanning 632.8-nm light by an unprecedented 14.88 degrees angle for extraordinary polarized light and by 4.05 degrees for ordinary polarized light. The device concept is based on micropatterning ferroelectric domains in the shape of a series of optimized prisms whose refractive index is electric field tunable through the electro-optic effect. We demonstrate what we believe is a novel technique of using electro-optic imaging microscopy for in situ monitoring of the process of domain micropatterning during device fabrication, thus eliminating imperfect process control based on ex situ monitoring of transient currents.

Abnormal positive potentials in round window electrocochleography.

OBJECTIVE: To describe an atypical waveform, termed an abnormal positive potential (APP), on round window electrocochleograms (RW ECochG) of children and to relate its occurrence to clinical history. STUDY DESIGN: APPs were identified prospectively, and a retrospective analysis was made of these patients' clinical histories, audiograms, and auditory outcomes (hearing aid, cochlear implant, or nonauditory communication) SETTING: Tertiary referral teaching hospital, day surgery and clinics. PATIENTS: All 431 children <110 months of age suspected of a severe to profound hearing loss who underwent RW ECochG from January 1993 to August 1997. INTERVENTION: Diagnostic RW ECochG for auditory threshold estimation. MAIN OUTCOME MEASURE: The presence on the RW ECochG of the APP: an early positive potential in the absence of a compound action potential (CAP). RESULTS: An APP was observed in 34 children. The APP was most marked in response to clicks and 8-kHz tones. The APP click threshold averaged 70 dB hearing loss. The brainstem evoked potential of these children showed an absence of waves, or a broad positive wave with no subsequent waves. Twenty-nine of 30 behavioral audiograms obtained were indicative of severe to profound hearing loss. Auditory outcomes were available from 26 children; 45% of them derived no help from a hearing aid, and 8 children received a cochlear implant. Clinical factors frequently associated with APP were prematurity in combination with kemicterus or hypoxia. CONCLUSIONS: APP thresholds were lower than neural thresholds or behavioral thresholds. Children with APP need close follow-up, because half of those studied needed nonauditory strategies to develop effective communication.

Performance after cochlear implantation: a comparison of children deafened by meningitis and congenitally deaf children.

The speech perception and speech production performance following cochlear implantation of congenitally deaf children and children deafened by meningitis were analysed. Three groups consisting of 70 congenitally deaf children, 22 children deafened by meningitis before two years of age and 14 children deafened by meningitis after two years of age were compared. The group deafened by meningitis after two years of age demonstrated significantly better speech perception than the other two groups. Their speech production appeared better but did not achieve statistical significance compared with the other two groups. There was no significant difference in either speech perception or speech production between the congenitally deaf group and the group deafened by meningitis before two years of age.

Positioning of the receiver-stimulator for the CI-24M cochlear implant in infants.

A new cochlear implant (CI-24M) has recently been released by Cochlear Ltd. The shape and size of the receiver-stimulator differs from that of the CI-22M. Infants as young as one year of age are now receiving cochlear implants. We have examined the likely effect of skull growth following the implantation of a CI-24M cochlear implant in an infant of this age.

Integrated electro-optic lens/scanner in a LiTaO3 single crystal.

We report what we believe to be the first stand-alone integrated electro-optic lens and scanner fabricated on a single crystal of Z-cut LiTaO(3). The independently controlled lens and scanner components consist of lithographically defined domain-inverted regions extending through the thickness of the crystal. A lens power of 0.233 cm(-1) kV(-1) and a deflection angle of 12.68 mrad kV(-1) were observed at the output of the device.

Traumatic laryngocoele.

This is the first reported case of a laryngocoele developing after laryngeal trauma. A 26-year-old man sustained a shotgun injury to his larynx. A large number of shotgun pellets was removed from his left vestibular fold. He subsequently developed a left-sided laryngocoele, probably due to fibrosis around the neck of the saccule. The laryngocoele was removed by an external approach.

Hairy polyp of the tonsil.

Hairy polyps or dermoids of the oro- and naso-pharynx are benign lesions containing elements of both ectodermal and mesodermal origin. We report a case of a hairy polyp arising from the tonsil in a three-week-old infant. This presented as an intermittent swelling in the mouth, which was successfully removed under general anaesthesia. To our knowledge this is only the third case of a hairy polyp arising at this site to be reported. We discuss the terminology applied to these lesions and review the literature.

Eye protection during mastoid surgery.

A questionnaire was sent to all Full Members of the British Association of Otolaryngologists to ascertain whether and what type of eye protection surgeons and theatre nurses wear during mastoid surgery. Despite Department of Health recommendations only 58 per cent of surgeons and 19 per cent of theatre nurses routinely wear any form of eye protection.

Spontaneous rupture of a congenital diaphragmatic eventration.

A 51-year-old man presented as an emergency with acute intestinal obstruction following herniation of abdominal contents into the left hemithorax through a spontaneous rupture of his eventrated left hemidiaphragm. He underwent a left thoracotomy with reduction of the herniated abdominal contents, repair of the diaphragmatic rupture and plication of the diaphragm. He made an uneventful recovery and remains asymptomatic. This is the first reported case of spontaneous rupture of an eventration of the diaphragm.

Preparation of cross-sectional specimens of ceramic thermal barrier coatings for transmission electron microscopy.

During the microstructural examination of ceramic thermal barrier coatings by transmission electron microscopy (TEM), initial efforts for the preparation of cross-sectional thin foils from interface regions by conventional means were mostly failures. Delamination of the Y2O3-stabilized ZrO2 ceramic coating from the nickel-base alloy substrate sometimes occurred during fine polishing at around 80 microns thickness but mostly occurred during dimpling. Because of this sensitivity, special techniques for mechanical handling were developed so that ion milling could give thin enough regions of the metal-ceramic interface. TEM showed convincingly that the highly fragile nature of the coatings is in fact due to the extensive porosity at the interface developed as a result of heat treatment.