Facing the Inevitable: Being Prepared for Regulatory Requirements for Laboratory Developed Tests

OBJECTIVES

We introduce regulatory terms, definitions, and the Quality System Regulation as proposed by the US Food and Drug Administration in the 2014 draft guidance entitled Framework for Regulatory Oversight of Laboratory Developed Tests and explore medical device requirements applicable to a laboratory environment to design, develop, and validate laboratory developed tests (LDTs).

METHODS

We performed nine interviews with laboratory professionals to explore concerns and challenges regarding the draft, translated the results into operational factors, and surveyed professionals to test the factors that would comprise a regulatory quality management system framework.

RESULTS

Nine interviewees and 35 survey respondents shared concerns of risk classification, process validation, patient safety, and general ambiguity regarding the proposed requirements for development of LDTs.

CONCLUSIONS

Respondents agree that a regulatory quality management system is needed in laboratories that develop LDTs, but the translation and method for design control to a clinical laboratory do not exist. As a result, laboratories are taking the wait-and-see approach.

Iatrogenic facial nerve injuries during chronic otitis media surgery: a multicentre retrospective study

OBJECTIVES

To give an insight into why, when and where iatrogenic facial nerve (FN) injuries may occur and to explain how to deal with them in an emergency setting.

DESIGN AND SETTING

Multicentre retrospective study in eight tertiary referral hospitals over 17 years.

PARTICIPANTS

Twenty patients with partial or total FN injury during surgery for chronic otitis media (COM) were revised.

MAIN OUTCOME MEASURES

Indication and type of surgery, experience of the surgeon, intra- and postoperative findings, value of CT scanning, patient management and final FN outcome were recorded.

RESULTS

In 12 cases, the nerve was completely transected, but the surgeon was unaware in 11 cases. A minority of cases occurred in academic teaching hospitals. Tympanic segment, second genu and proximal mastoid segments were the sites involved during injury. The FN was not deliberately identified in 18 patients at the time of injury, and nerve monitoring was only applied in one patient. Before revision surgery, CT scanning correctly identified the lesion site in 11 of 12 cases and depicted additional lesions such as damage to the lateral semicircular canal. A greater auricular nerve graft was interposed in 10 cases of total transection and in one partially lesioned nerve: seven of them resulted in an HB III functional outcome. In two of the transected nerves, rerouting and direct end-to-end anastomosis was applied. A simple FN decompression was used in four cases of superficially traumatised nerves.

CONCLUSIONS

We suggest checklists for preoperative, intraoperative and postoperative management to prevent and treat iatrogenic FN injury during COM surgery.

Shared vision between fathers and daughters in family businesses: the determining factor that transforms daughters into successors

Family businesses are critical to the United States economy, employing 63% of the workforce and generating 57% of GDP (University of Vermont, 2014). Family business continuity, however, remains elusive as approximately 70% of family businesses do not survive the second generation (Poza, 2013). In order to augment our understanding of how next generation leaders are chosen in family businesses, we examine daughter succession. Using a sample of pairs of family business fathers and daughters and drawing on an earlier study of the dearth of successor daughters in family businesses (Overbeke et al., 2013), we reveal that shared vision between fathers and daughters is central to daughter succession. Self-efficacy and gender norms influence shared vision and when fathers and daughters share a vision for the future of the company, daughters are likely to be transformed into successors.

Psychosocial interventions for managing pain in older adults: outcomes and clinical implications

Interest in the use of psychosocial interventions to help older adults manage pain is growing. In this article, we review this approach. The first section reviews the conceptual background for psychosocial interventions with a special emphasis on the biopsychosocial model of pain. The second section highlights three psychosocial interventions used with older adults: cognitive behavioural therapy, emotional disclosure, and mind-body interventions (specifically mindfulness-based stress reduction and yoga). The final section of the paper highlights important future directions for work in this area.

Multidisciplinary management of vestibular schwannomas: state of the art

The preferred setting for the treatment for vestibular schwannoma these days is multidisciplinary and multimodal. A balance has to be struck between a wait-and-scan attitude and a more active approach (surgery or radiotherapy). An initial wait-and-scan attitude is a reasonable management option because many tumours do not grow during a prolonged period of observation. The different surgical approaches may or may not involve attempts to preserve hearing. Stereotactic radiotherapy as treatment of choice is often considered in the elderly patient presenting with a vestibular schwannoma smaller than 2.5 cm with documented growth. This paper will review current treatment modalities and the respective pros and cons. A decisional algorithm as currently adopted by our skull base team is presented at the end of the paper.

Prognostic significance of electrophysiological tests for facial nerve outcome in vestibular schwannoma surgery

OBJECTIVE

To assess the prognostic significance of pre-operative electrophysiological tests for facial nerve outcome in vestibular schwannoma surgery.

METHODOLOGY

Retrospective study design in a tertiary referral neurology unit. We studied a total of 123 patients with unilateral vestibular schwannoma who underwent microsurgical removal of the lesion. Nine patients were excluded because they had clinically abnormal pre-operative facial function. Pre-operative electrophysiological facial nerve function testing (EPhT) was performed. Short-term (1 month) and long-term (1 year) post-operative clinical facial nerve function were assessed.

RESULTS

When pre-operative facial nerve function, evaluated by EPhT, was normal, the outcome from clinical follow-up at 1-month post-operatively was excellent in 78% (i.e. HB I-II) of patients, moderate in 11% (i.e. HB III-IV), and bad in 11% (i.e. HB V-VI). After 1 year, 86% had excellent outcomes, 13% had moderate outcomes, and 1% had bad outcomes. Of all patients with normal clinical facial nerve function, 22% had an abnormal EPhT result and 78% had a normal result. No statistically significant differences could be observed in short-term and long-term post-operative facial function between the groups.

CONCLUSION

In this study, electrophysiological tests were not able to predict facial nerve outcome after vestibular schwannoma surgery. Tumour size remains the best pre-operative prognostic indicator of facial nerve function outcome, i.e. a better outcome in smaller lesions.

Diffusion-weighted magnetic resonance imaging of the temporal bone

This paper summarizes the value of diffusion-weighted magnetic resonance imaging in the evaluation of temporal bone pathology. It highlights the use of different types of diffusion-weighted magnetic resonance imaging in the different types of cholesteatoma, prior to first stage surgery and prior to second look surgery. The value of diffusion-weighted magnetic resonance imaging in the evaluation of pathology of the apex of the petrous bone and the cerebellopontine angle is also discussed.

Imaging of intralabyrinthine schwannomas: a retrospective study of 52 cases with emphasis on lesion growth

BACKGROUND AND PURPOSE

Only a few case reports and small series of intralabyrinthine schwannomas (ILSs) have been reported. The purpose of this study was to assess prevalence, MR characteristics, location, clinical management, and growth potential/patterns of ILSs in the largest series reported.

MATERIALS AND METHODS

Lesion localization, MR characteristics, lesion growth, and clinical management were reviewed in 52 patients diagnosed with an ILS between February 1991 and August 2007 in 2 referral centers. The number of ILSs and vestibulocochlear schwannomas in the cerebellopontine angle/internal auditory canal was compared to assess the prevalence.

RESULTS

ILSs most frequently originate intracochlearly, are hyperintense on unenhanced T1-weighted images, enhance strongly after gadolinium administration, and are sharply circumscribed and hypointense on thin heavily T2-weighted 3D images. The scala tympani is more frequently or more extensively involved than the scala vestibuli. Follow-up MR imaging, available in 27 patients, showed growth in 59% of subjects. Growth was seen from the scala tympani into the scala vestibuli and from the scala vestibuli to the saccule and vice versa. Twelve lesions were resected, and the diagnosis of ILS histopathologically confirmed.

CONCLUSION

ILSs can account for up to 10% of all vestibulocochlear schwannomas in centers specializing in temporal bone imaging, grow in more than 50%, and are most frequently found intracochlearly, often anteriorly between the basal and second turn. Cochlear ILSs most often originate in the scala tympani and only later grow into the scala vestibuli. Growth can occur from the cochlea into the vestibule or vice versa through the anatomic open connection between the perilymphatic spaces in the scala vestibuli and around the saccule.

Transient depression of inner ear function after stapedotomy: skeeter versus CO(2) laser technique

Performing stapes surgery for otosclerosis is known to be potentially irreversibly harmful to the inner ear function in about 1% of the cases. An early postoperative transient depression of the bone conduction thresholds is frequently detected after stapes surgery. The purpose of this study was to compare the evolution of bone conduction thresholds after primary stapedotomy with two different techniques: skeeter versus CO(2) laser stapedotomy. Audiological data of 336 otosclerosis operations performed by 2 surgeons between 1997 and 2003 were subjected to analysis. The calibrated hole in the footplate was performed randomly either with the skeeter drill or with the CO(2) laser. Preoperative bone conduction thresholds were compared with the postoperative levels (day 2-3, week 2, week 6 and month 6) in all patients. Evolution of the bone conduction was compared for the two studied subgroups (laser versus skeeter).

Single-shot, turbo spin-echo, diffusion-weighted imaging versus spin-echo-planar, diffusion-weighted imaging in the detection of acquired middle ear cholesteatoma

Diagnosis of acquired middle ear cholesteatoma on MR imaging is mostly done on late postgadolinium T1-weighted MR images and/or echo-planar (EPI) diffusion-weighted (DWI) MR images. We describe the appearance of a case of a complicated attical middle ear cholesteatoma on single-shot (SS) turbo spin-echo (TSE) DWI compared with EPI-DWI. This case suggests a higher reliability of SS TSE-DWI in the diagnosis of acquired middle ear cholesteatoma.

Allograft tympanoplasty

Tympano-ossicular allografts are human transplants of the tympanic membrane alone or with the ossicles included. The authors review its use in their department since the introduction of the technique 40 years ago by J. Marquet. The advantages of the technique (near normal anatomical and physiological reconstruction) are discussed, as well as its disadvantages (time consuming harvesting, risk of disease transmission). Some technical modifications for specific indications have been adapted in our department and are described in detail. The authors believe that the tympano-ossicular allograft is the material of choice in extensively diseased middle ears destroyed by chronic otitis media with or without cholesteatoma.

Otosclerosis: a genetically heterogeneous disease involving at least three different genes

Otosclerosis is caused by abnormal bone homeostasis of the otic capsule, resulting in hearing impairment in 0.3%-0.4% of the white population. The etiology of the disease remains unclear and environmental as well as genetic factors have been implicated. We localized the first autosomal-dominant locus to chromosome 15 in 1998 (OTSC1) in an Indian family and, recently, we reported the localization of a second gene for otosclerosis to a 16 cM interval on chromosome 7q (OTSC2). In this study, we recruited and analyzed nine additional families (seven Belgian and two Dutch families with 53 affected and 20 unaffected subjects) to investigate the importance of these loci in autosomal-dominant otosclerosis. We completed linkage analysis with three microsatellite markers of chromosome 15 (D15S652, D15S1004, D15S657) and five microsatellite markers of chromosome 7 (D7S495, D7S2560, D7S684, D7S2513, D7S2426). In two families, results compatible with linkage to OTSC2 were found, but in the seven remaining families OTSC1 and OTSC2 were excluded. Heterogeneity testing provided significant evidence for genetic heterogeneity, with an estimated 25% of families linked to OTSC2. These results indicate that, besides OTSC1 and OTSC2, there must be at least one additional otosclerosis locus.

CT and MR imaging of congential abnormalities of the inner ear and internal auditory canal

The embryology of the inner ear must be known as many of the inner ear malformations present as a result of the arrest during the various stages of embryology. These malformations are described in this "embryologic" perspective and specific names for certain malformations are no longer used. Both CT and MR can be used to look at inner ear malformations but often both techniques are complementary. However, CT is preferred when associated middle- or external ear malformations must be excluded. Magnetic resonance is preferred when subtle changes in the membranous labyrinth or abnormalities of the nerves in the internal auditory canal must be visualised. The CT and MR technique must however be adapted as more and more subtle congenital malformations can only be seen when the right technique is used. The heavily T2-weighted gradient-echo or fast spin-echo MR techniques are mandatory if malformations of the inner ear must be excluded. The purpose of this paper is to describe the techniques used to study these patients and to give an overview of the most frequent and important congenital malformations which can be found in the inner ear and internal auditory canal/cerebellopontine angle.

A Two-stage bipodal screening model for universal neonatal hearing screening

OBJECTIVE

A model is proposed for universal neonatal hearing screening.

METHODS

The screening model is two-staged because it consists of a first test and, in case of failure (1.4% of the subjects), of a retest 3 weeks later. It is bipodal because it involves both the hospital audiologic department and a central Well Baby Organization. The idea is to have a maximal number of newborns tested at the maternity by trained audiologists and to have the Well Baby Organization trace and chase the missing subjects. The model has been evaluated during 1 calendar year (1999) in a maternity with 2,012 newborns.

RESULT

The result is a coverage of 99.3%. Most newborns (97.3%) were tested at the maternity ward with a total time investment of less than 15 minutes per child. The actual test time is 2 minutes, 12 seconds (median value). The Well Baby Organization keeps track of all the results and has to test no more than 2% of the newborns. Sensitivity and specificity were not the primary outcomes of this evaluation, but they were similar to those of a previous study evaluating the screen procedure on a larger scale, giving a sensitivity of approximately 100% and a false alarm rate of 1/1,000.

CONCLUSION

These figures demonstrate that universal neonatal hearing screening is feasible within the existing health care structure, with unprecedented coverage, sensitivity, and specificity.

Giant congenital intracranial epidermoid tumor: a case report

A case of a large epidermoid tumor in a middle-aged woman with limited symptomatology is reported. Intracranial epidermoid tumors are slow growing and benign lesions. Although the treatment of choice consists in complete resection, partial removal may be preferred in some very extended cases presenting with minimal symptomatology because of the lower morbidity involved. This case illustrates a key-hole approach via a retrolabyrinthine route with preservation of all labyrinthine structures, including the endolymphatic sac and duct. The epidermoid was partially removed by extensive intracapsular debulking under endoscopic control with the aim of decreasing cerebral compression. All cranial nerve functions were preserved and the 6 month postoperative imaging has remained unchanged over a 2-year long follow-up period. The literature regarding this rare pathology is also reviewed.

Contralateral Suppression of Transient Evoked Otoacoustic Emissions: Normative Data for a Clinical Test Set-Up

HYPOTHESIS

Contralateral suppression of transient evoked otoacoustic emissions (TEOAEs) can be used in a clinical set-up using a procedure based on a unique and robust parameter to quantify the magnitude of suppression for a subject.

BACKGROUND

TEOAEs can be suppressed by delivering contralateral white noise (WN). This suppression is thought to be mediated via the efferent nerve fibers that innervate the outer hair cells. The ipsilateral TEOAE-eliciting click stimulus level and the contralateral WN level have a strong impact on the recorded level of suppression.

METHODS

TEOAEs were recorded using the nonlinear stimulation mode in two conditions (with and without contralateral WN). An optimal TEOAE-eliciting click stimulus level and contralateral WN level were defined to obtain a unique and robust parameter to quantify the magnitude of suppression.

RESULTS

Suppression of TEOAEs with contralateral WN can be measured in a clinical set-up using nonlinear stimulation, and the level of suppression is of the same order of magnitude as measures using the linear stimulation recording mode. The level of suppression appears to be "locked" to the interaural difference between ipsilateral TEOAE-eliciting broadband click stimulus level and the contralateral WN level.

CONCLUSIONS

A procedure is proposed to record contralateral suppression in a clinical set-up, and normative data are given for a normal-hearing population (n = 60).

A second gene for otosclerosis, OTSC2, maps to chromosome 7q34-36

Otosclerosis due to abnormal bone homeostasis of the otic capsule is a frequent cause of hearing loss in adults. Usually, the hearing loss is conductive, resulting from fixation of the stapedial footplate, which prevents normal ossicular vibration in response to sound. An additional type of sensorineural hearing loss may be caused by otosclerotic damage to the cochlea. The etiology of the disease is unknown, and both environmental and genetic factors have been implicated. Autosomal dominant inheritance with reduced penetrance has been proposed, but large families are extremely rare. To elucidate the pathogenesis of the disease, identification of the responsible genes is essential. In this study, we completed linkage analysis in a Belgian family in which otosclerosis segregates as an autosomal dominant disease. After excluding linkage to a known locus on chromosome 15 (OTSC1), we found linkage on chromosome 7q, with a multipoint LOD score of 3.54. Analysis of key recombinant individuals maps this otosclerosis locus (OTSC2) to a 16-cM interval on chromosome 7q34-36 between markers D7S495 and D7S2426.

Prognostic value of magnetic resonance imaging findings in hearing preservation surgery for vestibular schwannoma

OBJECTIVE

The purpose of this study was to determine whether three magnetic resonance imaging (MRI) findings (tumor size, extension to the fundus, intralabyrinthine signal intensity) have a predictive value to hearing preservation in vestibular schwannoma surgery.

STUDY DESIGN

A retrospective study was conducted of preoperative high-resolution MR images in a series of consecutive hearing preservation attempts for vestibular schwannomas.

PATIENTS

Twenty-six consecutive records of patients with an acoustic tumor removed via a retrosigmoid transcanal approach were analyzed, and the MR images were reviewed blindly and compared with postoperative hearing.

SETTING

The study took place in a tertiary referral center. Imaging Techniques: The MR sequences used in this study were unenhanced and gadolinium-enhanced T1-weighted spin-echo images and gradient echo images (3DFT-CISS).

MAIN OUTCOME MEASURES

The predictive value of three MRI signs was analyzed: tumor size, lateral extension of the tumor (with and without obliteration of the fundus), and the maintenance of, or decrease in, the intralabyrinthine signal intensity on the affected side in comparison with the signal intensity on the opposite normal side as seen on 3DFT-CISS images.

RESULTS

The tumor size in ears in which hearing was preserved averaged 15 mm and was 17 mm in those cases where hearing was not preserved. Hearing was preserved in 50% of ears when the tumor did not extend to the fundus but in only 33% when the fundus was obliterated by tumor. A "normal" intralabyrinthine signal on CISS images (being an isointense signal when compared with the contralateral unaffected ear) was followed by hearing preservation in 82% of ears, whereas in cases where the intralabyrinthine signal was low, hearing was preserved in only 20%. This correlation was statistically significant (p < 0.05).

CONCLUSION

The intralabyrinthine signal intensity on 3DFT-CISS gradient-echo images is a valuable additional tool for determining candidacy for hearing preservation surgery. In two cases with preoperative decrease in signal intensity of the intralabyrinthine fluids, control MRI after surgery showed spontaneous recovery of normal intralabyrinthine signal intensity. The authors hypothesize that vascular compression in the internal auditory canal by the tumor is responsible for the observed intralabyrinthine signal decrease.

Audiological findings in large vestibular aqueduct syndrome

An enlarged vestibular aqueduct is a congenital disorder causing early onset and progressive hearing loss in children. This paper presents the audiological findings at first presentation and the audiological evolution in 10 consecutive cases presenting with hearing loss and showing a large vestibular aqueduct on imaging. The reported onset of the hearing loss is within the first few years of life. Most of the cases (80%) showed bilateral involvement. The sex ratio was 1. Patients presented on average at age 5 with a median hearing loss of 62 dB at the speech frequencies. The hearing loss was essentially asymmetrical with an interaural difference, of 33 dB and it was a mixed type of hearing loss in 90% of the cases. The authors claim that the conductive component of this hearing loss is a pure cochlear conductive loss which may be pathognomonic for the disease. The presence of a conductive component in a child is easily misinterpreted as a middle ear ventilation problem or in case of good ventilation as an ossicular problem (type otosclerosis). In addition and in contrast to most literature data, the authors did not find evidence for stabilization of the hearing loss but they found a steady decrease of the hearing at an average rate of 4 dB/year.

Neonatal hearing screening with transient evoked otoacoustic emissions: a learning curve

The present paper reports on the implementation of a neonatal hearing screening programme in a private hospital in Belgium. A maternity-based neonatal hearing screening project with transient evoked otoacoustic emissions (TEOAEs) was started in 1993. The cost of the test was not covered by the public health insurance, so the parents had to pay the full cost for screening their child (approximately 30 Euro). Since 1993 the programme strategies have been changed on several occasions to improve the quality and efficacy. A retrospective analysis was performed on: (1) the test pass rate; (2) the coverage; and (3) the number of children who become 'Lost to follow-up' after failing the initial test. The data show a steady learning curve with a time course of several years. They also demonstrate that it is worthwhile and feasible to run a high-quality screening programme in a private establishment.

Large intrapetrous facial schwannoma presenting as a glomus tumor

A 45 y old man suffered since a long time from right-sided hearing loss, tinnitus and, very recently, facial palsy. CT-scanning and MRI showed a very large intrapetrous lesion centered on the jugular foramen suggestive for a glomus tumor. During surgery a facial schwannoma was disclosed. The management and therapy of this lesion is discussed.

A new autosomal-dominant locus (DFNA12) is responsible for a nonsyndromic, midfrequency, prelingual and nonprogressive sensorineural hearing loss

OBJECTIVE

This study aimed to report on the audiologic findings of a nonsyndromic autosomal-dominant hearing loss of which the gene (DFNA 12) recently was found to map to chromosome 11q22-24. The study also aimed to propose and evaluate an algorithm based on the audiometric findings to discriminate between affected and unaffected family members before genetic linkage analysis.

STUDY DESIGN

The study design was a retrospective analysis of the audiometric data of genetically affected and unaffected patients.

SETTING

The study was conducted at a tertiary referral center.

PATIENTS

A total of 17 genetically affected and 54 unaffected family members were studied.

INTERVENTIONS

Pure-tone audiometry with air and bone conduction and construction and evaluation of an algorithm were performed.

MAIN OUTCOME MEASURES

The type and degree of hearing loss as compared to age and gender-dependent values according to the International Organization for Standardization 7029 standard were measured. For this comparison, the variable "hearing standard deviations" (HSD) is introduced and is defined as the number of standard deviations that a hearing threshold is lying above the age and gender-related median at the given frequency. A description of the algorithm and an evaluation in terms of alpha- and beta-error also were measured.

RESULTS

The hearing loss is nonsyndromic, sensorineural, moderate-to-moderately severe (pure-tone average, 51 dB at age 18 years), with an early onset (probably prelingual) and no progression. It affects all frequencies but mainly the midfrequencies (500, 1,000, and 2,000 Hz). The algorithm consists of an analysis of variance to determine the frequency that is most sensitive for the genetic trait under study and on the ranking of the family members according to their hearing loss (HSD) at this frequency. Individual persons are labeled as "affected" or "unaffected" according to this ranking.

The LAURA Pediatric Cochlear Implant Program in Antwerp: what have we learnt in 5 years?

The LAURA Cochlear Implant Program at the University of Antwerp was initiated 5 years ago. Up to now 50 children have received the LAURA cochlear implant (Philips Hearing Implants). Our accumulated experience in selecting the patients, counselling their parents, implanting and fitting the device allowed us to gradually modify the inclusion/exclusion criteria for cochlear implantation and achieve very rewarding results. The most important change was the gradual shift towards a younger age at implantation, our youngest implantee being 11 months old. In this paper we describe the rationale for this change, as well as the prerequisites for a successful pediatric cochlear implant program.

Growth factors in tympanic membrane perforations

OBJECTIVE

Little is known about the arrested healing of chronic central tympanic membrane perforations and the mechanism involved in this process. Some authors have traced the failure to a growth factor deficiency at the perforation margin. In addition, recently, several growth factors have been tried out to improve tympanic membrane (TM) closure in animals. The authors sought to determine the expression of some well-known growth factor peptides in normal human TM and in TMs with a chronic central perforation.

MATERIALS AND METHODS

Total TM specimens were obtained from patients with a normal TM (N = 10) soon after death and from patients with a chronic perforation (N = 20) undergoing myringoplasty with use of an allograft TM. Formaldehyde solution-fixed TMs were analyzed after immunohistochemical staining using highly purified monoclonal antibodies to determine whether epidermal growth factor receptor (EGF-r), transforming growth factor-alpha (TGF-alpha), basic fibroblast growth factor (b-FGF), or transforming growth factor-beta 1 (TGF-beta 1) was expressed in the TMs.

RESULTS

The distribution pattern for EGF-r, TGF-alpha, and b-FGF was similar in perforated and nonperforated TMs. In contrast to this, TGF-beta 1 staining was markedly different in perforated and nonperforated TMs. No or minimal TGF-beta 1 was observed in normal TMs, whereas TGF-beta 1 staining was prominent in perforated membranes, mostly at the perforation border.

CONCLUSIONS

The authors experimental findings imply that EGF-r, b-FGF, and TGF-alpha expression are not significantly different in TMs with and without a central chronic perforation. However, for TGF-beta 1, the authors found an increased staining pattern in perforated TMs when compared with that of normal TMs, and staining at the fibrotic and scarred perforation margin was pronounced. Based on these findings, the authors speculate on the possible role of TGF-beta 1 in the development of the fibrotic scar at the perforation margin explaining the deficient healing pattern of tympanic membranes in chronic otitis media. Possible clinical implications for the future, including growth factor therapy, are discussed.

Box and whisker plots for graphic presentation of audiometric results of conductive hearing loss treatment

The Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery has published guidelines for the reporting of audiometric results of middle ear interventions. It recommends the reporting of several audiometric variables by means of two summary parameters: means and standard deviation. This article advocates the use of other summary statistics, namely the median, quartiles, and extremes, because they do not require a normal distribution of the audiometric data and they are not sensitive to variations of the extreme values. On the basis of the exploratory data analysis, we propose a graphic method to present the Committee's variables in terms of their summary statistics. This "multiple box and whisker plot" offers a detailed and accurate overview of six variables in one graph.

Mutations in the human alpha-tectorin gene cause autosomal dominant non-syndromic hearing impairment

The tectorial membrane is an extracellular matrix of the inner ear that contacts the stereocilia bundles of specialized sensory hair cells. Sound induces movement of these hair cells relative to the tectorial membrane, deflects the stereocilia, and leads to fluctuations in hair-cell membrane potential, transducing sound into electrical signals. Alpha-tectorin is one of the major non-collagenous components of the tectorial membrane. Recently, the gene encoding mouse alpha-tectorin (Tecta) was mapped to a region of mouse chromosome 9, which shows evolutionary conservation with human chromosome 11q (ref. 3), where linkage was found in two families, one Belgian (DFNA12; ref. 4) and the other, Austrian (DFNA8; unpublished data), with autosomal dominant non-syndromic hearing impairment. We determined the complete sequence and the intron-exon structure of the human TECTA gene. In both families, mutation analysis revealed missense mutations which replace conserved amino-acid residues within the zona pellucida domain of TECTA. These findings indicate that mutations in TECTA are responsible for hearing impairment in these families, and implicate a new type of protein in the pathogenesis of hearing impairment.

Total auricular repair: bone anchored prosthesis or plastic reconstruction?

Major breakthroughs in implantology and prosthetic materials, but also in reconstructive surgery of the auricle, have opened new possibilities in the rehabilitation of patients with an absent auricle. The management of such cases and the surgical results in 62 cases are presented. Thirty-five bone-anchored prostheses have been adapted and 27 total auricular reconstructions performed. As long as the conditions of osseo-integration are respected, surgery for an epithesis is easy and comprises no major risks. The side effects of the percutaneous connection (mainly skin reactions) are often minor. All patients are satisfied with their prosthesis and wear it all day long. For the total auricular repair, mainly in major congenital malformations, two techniques were adopted: first the Brent technique followed by the Nagata technique, preferred nowadays. The Brent technique was found safe with good results, but the modification by NAGATA offered two additional advantages: a reduction of the operative stages from 4 to 2 and a better definition of the auricular reliefs by the more elaborate fabrication of the framework. With increasing experience the results of the total auricular reconstructions improved significantly and became more predictable. Also the advantages and disadvantages of both (the reconstructive and prosthetic) approaches are discussed.

Use of antibiotic prophylaxis in ear surgery

A prospective, double-blind, randomized, placebo-controlled study was performed to evaluate the effect of antibiotic prophylaxis in ear surgery. The present study reports on the results of 750 patients, half of whom received cefuroxime for 1 day, the other half, placebo. All postoperative infections occurring within 2 weeks after the intervention were recorded, together with several preoperative and perioperative parameters. It is concluded that exploratory tympanoplasties (including stapedotomy) and "dry perforation" tympanoplasties should be considered "clean" operations according to the American National Research Council and do not benefit from antibiotic prophylaxis. On the other hand, tympanoplasties performed on draining ears and on ears with cholesteatoma should be considered "dirty" operations for which antibiotic prophylaxis may decrease the postoperative infection rate by factor 3. All postoperative infections healed without sequels under proper treatment, except for three that resulted in graft necrosis--one in the placebo group and two in the cefuroxime group. In consequence, prophylaxis may not be mandatory in the dirty group, although the authors advocate its use for the sake of patient and surgeon comfort.

Stimulation of epithelial healing in chronic postoperative otorrhea using lyophilized cultured keratinocyte lysates

OBJECTIVE

After tympanoplasty, despite a closed tympanic graft, some patients continue to have persistent otorrhea due to insufficient epithelial healing and granulation tissue formation in the depths of the outer ear canal. When all medical therapies fail, many otologists undertake revision surgery, usually with free skin grafting. To avoid surgery, the authors sought to improve this condition with a lysate of lyophilized cultured allogeneic keratinocytes.

STUDY DESIGN AND PATIENTS

In this prospective pilot study, lyophilized cultured allogeneic keratinocyte lysates have been administered in 27 patients. These patients had uncontrollable otorrhea that resisted medical (topical) therapy for at least 6 months.

MAIN OUTCOME MEASURE

The criterion of success was a complete epithelialization and cessation of otorrhea.

RESULTS

After an average of 2 applications, cessation of otorrhea was achieved in 20 cases (74%). Three patients (11%) relapsed after 3 months. The other ears (63%) still were dry at the 1-year final evaluation.

CONCLUSIONS

These results are similar to those obtained after application of sheets of viable cultured keratinocytes of autologous as well as of allogeneic origin. Because the soluble lysate can be incorporated into ototopical drops, the lysate technique is more "user-friendly" and can be applicable in any outpatient clinic. Because keratinocytes contain many growth factors (e.g., epidermal growth factor, basic fibroblast growth factor, platelet-derived growth factor, transforming growth factor), the authors speculate that the release of those intracellular growth factors is responsible for the observed therapeutic effect. This form of therapy by its combination of several growth factors might be considered a more physiologic method than the, also still experimental, growth factor therapy in which high doses of only single growth factor are used.

Tympano-ossicular allografts for cholesteatoma in children

At the Sint Augustinus Hospital, Antwerp, Belgium, all children with cholesteatoma are operated by a canal wall up approach and immediate reconstruction with a tympano-ossicular allograft. In the majority of the cases, a second stage is performed after 1 year. This paper presents the results of a retrospective review of the charts of 103 consecutive children treated between 1979 and 1995. The mean patient age was 10 years and the mean postoperative follow-up was 4.5 years. In 28 children residual cholesteatoma was found at the second stage operation and 20 developed recurrent cholesteatoma in the course of time. So far no residual cholesteatoma surfaced after the staged procedure, but 11 children needed more than two operations to control recurrent disease. An intact, trouble-free graft was present in 79 children at the latest follow-up. The median postoperative bone-conduction thresholds were equal to the preoperative thresholds. The median postoperative air-conduction thresholds improved in 50% of the cases, remained unchanged in 25%, and deteriorated in 25% of the cases. It is concluded that the tympano-ossicular allograft technique is effective and safe and offers good anatomical and acceptable functional results.

A gene for autosomal dominant nonsyndromic hearing loss (DFNA12) maps to chromosome 11q22-24

We performed linkage analysis in a Belgian family with autosomal dominant midfrequency hearing loss, which has a prelingual onset and a nonprogressive course in most patients. We found LOD scores >6 with markers on chromosome 11q. Analysis of key recombinants maps this deafness gene (DFNA12) to a 36-cM interval on chromosome 11q22-24, between markers D11S4120 and D11S912. The critical regions for the recessive deafness locus DFNB2 and the dominant locus DFNA11, which were previously localized to the long arm of chromosome 11, do not overlap with the candidate interval of DFNA12.

Aplasia and hypoplasia of the vestibulocochlear nerve: diagnosis with MR imaging

PURPOSE

To introduce aplasia or hypoplasia of the vestibulocochlear nerve (VCN) as a possible cause of hearing loss and to identify the magnetic resonance (MR) imaging characteristics of this entity.

MATERIALS AND METHODS

In seven patients with congenital deafness or unexplained sensorineural hearing loss, MR imaging enabled diagnosis of aplasia or hypoplasia of the VCN. Axial (0.7-mm) three-dimensional Fourier transformation-constructive interference in steady state (3DFT-CISS) images and parasagittal reconstruction images perpendicular on the course of the VCN were obtained. Twenty normal inner ears were also studied; their findings were compared with those of the patients.

RESULTS

The facial nerve and inferior and superior vestibular and cochlear branches of the VCN were identified on the MR images in the 20 normal inner ears. Aplasia of the VCN was detected in two patients with normal labyrinths but with a severe stenosis of the internal auditory canal. A common VCN with absence of the cochlear branch was found bilaterally in two patients with a congenital malformation of the labyrinth. A common VCN with absence or hypoplasia of the cochlear branch was found in three patients with normal internal auditory canals and labyrinths.

CONCLUSION

Submillimetric gradient-echo images (eg, 3DFT-CISS) should always be used to exclude aplasia or hypoplasia of the cochlear branch of the VCN in all cochlear implant candidates and patients with congenital deafness. This entity, which can occur with or without associated labyrinthine malformation, should be confirmed in two planes.

Revision stapes surgery

This paper reports on the analysis of 332 otosclerosis revision operations. The results have been evaluated with reference to the type of the procedure at primary surgery, the alleged cause of failure and the applied technical solution. The need for revision surgery was found higher after primary total stapedectomy (3.4 per cent) than after partial stapedectomy (2.2 per cent) or stapedectomy (two per cent). The reason for revision varied according to the originally applied technique eg a migrated piston, a too short piston and a lateralized graft are almost exclusively found after total stapedectomies. The median hearing gain after revision of stapedectomy and partial stapedectomy was higher (20 dB and 18 dB respectively) than that after revision surgery for total stapedectomy (12 dB), but significantly lower than hearing gain after primary surgery (32 dB). Revisions yielded better results in the case of primary interventions with the use of a piston or pistonwire than in the case of primary interventions with a wire-type prosthesis. The risk for sensorineural loss (one per cent) was not higher than in primary surgery.

Treatment of chronic postoperative otorrhea with cultured keratinocyte sheets

Cultured allogeneic ear keratinocyte sheets were used to treat 26 ears presenting with long-standing (average 37 months) chronic otorrhea, resistant to regular treatment, long after surgery for atresia (n = 8), cholesteatoma (n = 10), and chronic otitis media (n = 8). Complete epithelial healing and cessation of otorrhea were obtained in 18 cases (69%), following an average of 2.2 weekly applications. Temporary epithelial healing lasting at least 3 months was observed in 3 patients (12%) subsequently needing repeated applications. Lack of complete epithelialization was documented in 5 cases (19%). In 3 of those 5 cases, a reason could be determined. The authors speculate that the allocultured keratinocytes are able to promote migration and proliferation of resident cells at the wound edges, despite their short survival time, by release of keratinocyte-stimulating factors.

Allograft tympanoplasty type 1 in the childhood population

Seventy allograft type 1 tympanoplasties in children under 16 years of age were studied retrospectively. Only patients with a tympanic membrane perforation without cholesteatoma and a normal ossicular chain were included. Short-term and long-term anatomic and functional results were analyzed after a mean follow-up of 40 months. The overall short-term take rate was 97% and the long-term take rate was 88%. A number of variables with alleged prognostic value for surgical outcome were analyzed, but none showed statistical correlation with either anatomic or functional results. A median hearing gain of 10 dB was achieved, which was stable over time. We conclude that allograft tympanoplasty type 1 in this group of children is anatomically and functionally successful regardless of age.

Long-acting growth hormones produced by conjugation with polyethylene glycol

Derivatives of human growth hormone (hGH) of increasing size were produced by reaction with the N-hydroxysuccinimide ester of polyethylene glycol-5000 (PEG5000), a 5-kDa reagent that selectively conjugates to primary amines. By adjusting the reaction conditions and purification procedure, it was possible to isolate hGH derivatives containing up to seven PEG moieties that altered the Stokes radius and thereby the effective molecular masses of the unmodified hormone from 22 to 300 kDa. Fortunately, the most reactive amines were ones that did not lie in either of the two sites important for receptor binding. Nonetheless, increasing the level of PEG modification linearly reduced the affinity of hGH for its receptor and increased the EC50 in a cell-based assay up to 1500-fold. Most of the reduction in affinity was the result of slowing the association rate for the receptor. The clearance rate of hGH in rats was inversely proportional to effective molecular weight and closely fit a filtration model. We have tested the potency of these analogs by injecting them daily or every 6 days into hypophysectomized rats and determining the effects on body and organ growth. The efficacy of these analogs was optimal for hGH conjugated with 5 eq of PEG5000, and the potency was increased by about 10-fold compared with unmodified hGH. Such PEG-hGH derivatives show promise as long-acting alternatives to daily injections of hGH. More generally these studies show that improving hormone clearance properties, even at the expense of reducing receptor binding affinity, can lead to dramatic increases in hormone efficacy.

Numerical assessment of TOAE screening results: currently used criteria and their effect on TOAE prevalence figures

The literature on neonatal hearing screening by means of oto-acoustic emissions (OAE's) presents various prevalence figures, and gives little quantitative information on the procedure used to score the recordings. If the OAE test is to be interpreted by users who do not have the opportunity to develop intuitive interpretation skills through extensive training, a clear numerical decision criterion is needed. The present paper discusses the scoring procedure used by 25 teams, which together screen 22,356 neonates annually. More than 60% of the groups involved in this study use visual interpretation of the recorded OAE response, together with numerical criteria. Amongst the teams, 21 different ways of numerical scoring are used. It is shown that for a given set of OAE recordings, prevalence varies from 61% to 90%, depending on the numerical decision criterion being applied. We conclude that at this moment no consensus exists regarding the numerical criterion to be used when assessing OAE screening results. In view of the strong effect of criteria on the outcome of OAE screening, such consensus is urgently needed, but should be based on sensitivity and specificity figures for each scoring technique.

Lysates from cultured allogeneic keratinocytes stimulate wound healing after tympanoplasty

In the past, cultured keratinocyte allografts have been used with benefit in the treatment of burn wounds and leg ulcers. Since in burn wounds autologous and allogeneic fresh keratinocyte cultures were found to give similar favorable results as lysates of allogeneic cultured cells, the authors investigated whether this lysate mixed in an antibiotic suspension would also accelerate the epithelial healing after routine tympanoplasty. In a double blind setting the healing process in 50 consecutive tympanoplasty ears was studied: an acceleration of healing of 8 days was observed in the lysate-treated group (39.25 days) as compared with the control group (47.23 days). The percentage of ears which healed within 6 weeks (after 5 weekly applications of 200 microliters suspension in both groups) was significantly higher in the treated group (61%) than in the control population (36%). Although the therapeutical effect of the keratinocyte lysate in this study is believed to be due primarily to its mitogenic activity through growth factors or cytokines, at present it is still unclear which growth factors are involved and which combinations of these factors have to be present to modulate the different stages of the complex healing processes.

The LAURA multichannel cochlear implant in a true Mondini dysplasia

A congenitally deaf child with bilateral Mondini dysplasias of the inner ear was successfully implanted with a LAURA multichannel cochlear prosthesis. This is the first report of a patient with a Mondini dysplasia in whom a LAURA multichannel cochlear prosthesis was successfully implanted. The cerebrospinal fluid leakage typically occurring after cochleostomy in similar patients was readily controlled, indicating that the deformity present was not a contra-indication for cochlear surgery. The audiological results obtained are described in detail. Since the internal unit of the LAURA prosthesis is very flexible, various speech processing strategies, such as continuous interleaved and phase-locked continuous interleaved strategies, can be tried and evaluated.

Statistical analysis of otosclerosis surgery performed by Jean Marquet

The early and long-term hearing results of 1,681 primary otosclerosis operations performed by the same surgeon, Jean Marquet, were reviewed retrospectively and analyzed with very strict statistical standards. Significantly better short- and long-term results were achieved with the stapedotomy technique compared to total stapedectomy, mainly at the higher frequencies (4 and 8 kHz) important for speech discrimination. Whatever technique was used to open the footplate (micropick, microdrill, or laser), no statistical audiometric difference could be found. The results were equal whether or not the stapedial tendon was preserved. Perioperative problems like pronounced oozing, difficult anatomic relationships, and accidental perilymph aspiration could affect hearing at higher frequencies. The calibrated hole technique was equally as good as conventional oval window sealing in sealing of the fenestra to prevent fistula. The stapedotomy technique was found the safest, having fewer complications.

Preoperatively diagnosed utricular neuroma treated by selective partial labyrinthectomy

Unlike the acoustic neuroma that occupies the internal acoustic meatus and extends into the cerebellopontine angle, the true intralabyrinthine neuroma is an extremely uncommon finding. The majority of the published cases were found at autopsy or during destructive labyrinthectomy for uncontrollable Meniere's syndrome. To the best of our knowledge, we present the smallest exclusively intrautricular neuroma that has ever been diagnosed preoperatively. Detailed magnetic resonance imaging studies allowed the detection of this tumor, measuring only 3.5 mm in diameter. The tumor was removed via atticomastoidectomy and partial labyrinthectomy. The diagnostic workup, radiographic characteristics, and surgical treatment are discussed, together with a review of the literature.

Two-stage repair of extensive subglottic tracheal stenosis

The authors describe an open technique that has been used over the past 25 years to reconstruct the subglottic tracheal region in two stages after extensive laryngotracheal stenosis. After submucosal resection of fibrous tissue and reconstruction of the subglottic and tracheal skeleton by means of two autologous osseous grafts, a large laryngotracheostomy is created during the initial stage. Some weeks later, in the second stage, the anterior wall is closed, using two cervical hinge-door flaps. Ten patients have undergone this procedure, with a minimum follow-up of 3 years. All of the patients were decannulated upon completion of the treatment without recurrence of stenosis during the follow-up period.