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Biomedical subjects

T Somers

Publications and source records attributed to T Somers.

At least 37 records · Page 2Linked to original sources
PubMed1997

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.

Adolescent↗
PubMed1997

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.

Adolescent↗
PubMed1997

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.

Adult↗
PubMed1997

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.

Adolescent↗
PubMed1997

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.

Audiometry, Pure-Tone↗
PubMed1997

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.

Adolescent↗
PubMed1996

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.

Animals↗
PubMed1996

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.

Child↗
PubMed1996

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.

Adolescent↗
PubMed1996

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.

Administration, Topical↗
PubMed1996

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.

Adult↗
PubMed1996

Neonatal hearing screening with otoacoustic emissions: an evaluation.

For several years now, it is possible to test the cochlear function immediately after birth in an easy way by means of click evoked otoacoustic emissions. Thanks to this early detection, hearing aid fitting and appropriate hearing rehabilitation can now be started at a very young age, which significantly enhances the possibility of integration of the congenitally hard of hearing in society. An international consensus is growing to endorse a universal neonatal hearing screening in western societies. Setting up screening programs necessitates good preparation, continuous quality control and regular analysis of procedures and results. The present paper evaluates the procedure as organised from January 1993 till December 1994 in the University ENT-Department of the Sint-Augustinus Hospital. Of the 907 included neonates who were considered not to be at risk for hearing loss, 81% passed the test immediately, and 93% passed after maximum 3 tests. Some changes in the initial procedure increased the prevalence of emissions from 69% to 84%. The practical problems of the screening program and especially the importance of a stringent follow-up procedure in case of failure, are discussed.

Algorithms↗
PubMed1996

Hearing preservation surgery for acoustic neuroma.

Nowadays smaller acoustic tumors are being detected earlier. We started to remove these tumors with attempt of preservation of hearing in 1994. Since 1994, in an attempt to preserve hearing, the retrosigmoid approach was used. Our first results are presented and criteria of preoperative selection and postoperative evaluation are discussed. A fair chance to keep a useful hearing can be given to a patient with a small tumor, preferrably smaller than 1,5 cm and provided that the average hearing levels differ by no more than 30 dB from the other ear. In all the other cases the translabyrinthine route remains the preferred approach.

Adult↗
PubMed1994

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.

Ear, Inner↗
PubMed1994

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.

Adolescent↗
PubMed1994

The bone anchored hearing aid and auricular prosthesis.

The bone anchored hearing aid (B.A.H.A.) has been fitted to 10 of our patients presenting a bilateral profound conductive hearing loss and who were unable to wear a classical hearing aid. The group of patients with bilateral inoperable aural atresia (n = 5) formed the main indication and were found to give the best results. Cases with bilateral chronic otitis media (n = 5), presenting otorrhea each time a classical hearing aid was worn, formed the second indication. Audiometric performances are dependent on the bone conduction thresholds. The auricular epithesis has been adapted in 11 cases, mainly for atretic ears. The surgery for B.A.H.A. and epithesis is now routinely performed in one stage and has been found safe and reliable. The skin reactions around the abutments (total number fixtures = 32) were found to be rare and often easy to treat. Only around one abutment further subcutaneous tissue reduction was necessary to stabilize the skin. The B.A.H.A. and auricular epithesis are valuable alternatives in those cases where the limits of reconstructive (middle or outer ear) surgery are reached.

Adolescent↗
PubMed1990

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.

Bone Transplantation↗