Early experience on a modern, thin cochlear implant family. A retrospective, international multicenter study.

RATIONALE: Cochlear implantation is the most effective method of rehabilitation for patients with severe to profound sensorineural hearing loss. Binaural hearing forms the basis of the development of hearing-associated cortical networks in infants and toddlers, but simultaneous bilateral implantation is often postponed due to the demands of classical surgical methods, which are associated with large incisions and a deep bony well. OBJECTIVE: The authors report on the use of a modern, thin implant type and the possibilities it provided to simplify the surgical technique. METHODS AND RESULTS: Recent models of the Cochlear™ Nucleus® implant family were studied in an international retrospective multi-center study: 6 otolaryngologists in 5 centers shared their experiences on 73 consecutively implanted, thin implants. The surgical incision could be made shorter than before and only shallow bony wells or none at all were created in 4 out of 5 centers. No complications occurred. DISCUSSION: This study underlines that implants with thin electronics capsules enable a simplified, fast and safe implantation procedure that allows simultaneous bilateral cochlear implantation.

Revision operations after previous stapes surgery for persisting hearing loss.

OBJECTIVES: The aim of the study was to find out the reasons of the recurrent or persisting hearing loss after previous stapes surgery indicated for otosclerosis. BACKGROUND: Revision stapes surgery is a relatively safe surgical method. Recurrent or persisting conductive hearing loss is commonly caused by prosthesis dislocation and adhesions in the oval window. Hearing loss is directly proportional to the number of previous operations. METHOD: Retrospective analysis of 48 patients after revision stapes surgery was done over a period of 4 years (2005-2008). Improvement of the hearing and the reasons of a previous surgery failure were studied. RESULTS: RESULTS were compared to the other studies. The main reason of the failed surgery was adhesions and dislocation of the prosthesis. The mean postoperative air-bone gap was 12.0 dB. A mean postoperative air-bone gap closure within 10 dB occurred in 24 cases (55.8 %), between 11-20 dB occurred in 11 cases (25.6 %) and above 20 dB in 8 cases (18.6 %). The original prosthesis was replaced with a new one in 41 (95.3 %) cases. In 2 cases (4.7 %), previous prostheses were left in place and fixed by a ionomer glass cement to the long process of incus. CONCLUSION: Revision stapes surgery is a relatively safe surgical procedure allowing to improve hearing. The number of previous stapes surgery deteriorates hearing (p < 0.05) (Tab. 4, Ref. 20).

Our experience with surgical treatment of tympanojugular pragangliomas.

Tympanojugular paragangliomas are benign and slow growing lesions of the lateral skull base. Due to their localization and vascularity, they represent a surgical challenge. Treatment modalities include preoperative embolization of feeding vessels and tumour itself, surgical removal and irradiation. In our group, 16 patients with large tympanojugular paragangliomas have been operated in the period of 10 years. Surgical radicality has been achieved in 62.5%, in the rest of patients the tumour remnants were either irradiated with a Leksell gamma knife, or left without treatment in a wait-end-rescan approach. According to the benign character of the tumour, radicality is not always the highest goal, since a radical removal may be compromised by a high postoperative morbidity.

Occult thyroid carcinoma.

Some medical definitions remain the same for many years, others change due to the progress in the diagnostic tools, which are able to distinguish markers and symptoms until then undetectable. Occult thyroid carcinoma is a general term indicating clinically different situations, whereas the incidentally detected papillary thyroid microcarcinoma is the most important from the clinical point of view. It is fundamental, for therapeutic management, to determine biological parameters which would define a small group of papillary thyroid microcarcinomas with aggressive biological behaviour. The most promising genetic and molecular markers for papillary thyroid carcinoma risk stratification are discussed in this review. Preoperative evaluation of these markers, obtained through analysis of ultrasonography-guided fine needle biopsy specimens of papillary thyroid microcarcinoma, could be very valuable in guiding treatment of this type of cancer.

Complicated decisionmaking in indications for auditory brainstem implant (ABI) in a patient with neurofibromatosis 2.

A case of an accidental finding of neurofibromatosis 2 in a practically asymptomatic patient is described. Various therapeutic modalities, including restoration of hearing after vestibular schwannoma surgery with an auditory brainstem implant (ABI), are considered.

Magnetic resonance imaging of the rat brain after epileptic seizures--preliminary results.

The magnetic resonance imaging (MRI) of the rat brain after the epilepsy seizures has been performed. As a first step, the model of the kainic acid (KA) induced seizures has been conducted to examine the possibilities of magnetic resonance imaging system kept in disposition. Seven Wistar albino rats, weighing about 300 g, were used in this study. We administered six of them with intraperitoneal injection of 10 mg/kg of KA. The control animal received corresponding volume of the saline. Every animal was examined under systemic anaesthesia induced by an intraperitoneal injection of thiopental sodium approximately 15 minutes before scanning. Diffusion-weighted imaging (DWI) has been used to acquire the coronary scans of the rat brain. The progress of hyper intense signal at the cerebral cortex and amygdale has been observed. Marked asymmetry of the signal intensity between hemispheres has been discovered. Subsequently the experimental model of audiogenic epilepsy will be conducted.

Our surgical experience with large vestibular schwannomas.

Our aim is to remove large vestibular schwannomas (VS) radically with minimal morbidity. Usually, these tumours cannot not be treated by irradiation. In the years 1997-2003, 69 VS were operated in the Department of Otorhinolaryngology, Head and Neck Surgery of the First Medical Faculty in Prague, Czech Republic. Prevailing majority of these tumours were of the 4th grade (House classification), compressing the brainstem. Six patients in the group suffered from neurofibromatosis 2, in five cases the patients were indicated for neurosurgery due to rapid tumour growth after previous irradiation. All tumours were radically removed using a retromastoid osteoplastic and translab approach with an intraoperative nerve monitoring. Good function of the facial nerve was achieved in 90%. The nerve had to be resutured in 4 cases with consequent satisfactory results, cross anatomosis was not performed. Hearing function was preserved in 8% of patients only. In 6 patients with neurofibromatosis 2, the auditory brainstem implant (ABI) was used to preserve hearing. This study demonstrates that a radical removal of large vestibular schwannomas is possible using a minimally invasive surgical technique and peroperative nerve monitoring with a good impact on quality of life. Auditory brainstem implants bring a new chance of hearing after tumour removal in patients with NF2.

[Use of the auditory brainstem neuroprosthesis in the Czech Republic]. / Sluchová kmenová neuroprotéza v Ceské republice.

BACKGROUND: Auditory brainstem implant (ABI) is an electroprosthetic device enabling sound sensations in deaf persons with a bilateral lesion of auditory nerves. Stimulation of auditory nuclei in the floor of the IVth ventricle is realized by an electrode array introduced during surgery in the lateral recess of the IVth ventricle. METHODS AND RESULTS: The main indication group for ABI is represented by patients with neurofibromatosis 2 (NF2) suffering from bilateral vestibular schwannomas. During surgery aimed at tumour removal, auditory nerve function and integrity are almost always destroyed, therefore, an ABI can be introduced as an one stage procedure. Implantees use the device mainly as the aid in lipreading, only very rarely they can comprehend speech without visual cues. Auditory brainstem implant programme has been introduced in the Czech Republic in the year 1999. It was the very first ABI surgery in the Central Europe. Since that time, 5 patients had received the auditory brainstem implant, from which the first four use the device for a longer time. CONCLUSIONS: The last operated patient has not been activated yet. It may be said, that ABI represents a benefit to all our patients, in one implanted this benefit is significant, since he can understand speech without lipreading, the other implantees use the device as an aid in lipreading. In one female patient, the device benefit is severely limited by a motoric handicap after partial cerebellar resection during surgery. Nevertheless, she uses the implant on a daily basis, but contact with her is limited and difficult.

First auditory brainstem implant in the Czech Republic.

In the Czech Republic, the first implantation of a stimulation electrode into the brainstem was performed on 11 January 1999 in the Department of ORL, Head and Neck Surgery, The First Medical Faculty, Charles University in Prague, University Hospital Motol. The selected patient was a 40-year-old woman with neurofibromatosis type 2 (NF2) who had previously undergone bilateral vestibular schwannoma surgery. Both tumours had been radically removed, the left-sided tumour in 1987, the right-sided one in 1988. She had been completely deaf since the last operation, i.e., for 11 years. The surgery was realized by the international cooperation of three teams. Placement of the electrode pad of the Nucleus CI21 + 1M system on the ventral and dorsal cochlear nuclei was performed. Electrically evoked auditory brainstem responses (EABRs) proved the correct position of the electrode array. The post-operative course was uneventful. Six weeks after the surgery the patient received her speech processor. Since that time, the patient already absolved several sessions of a speech processor tune-up. She uses the device as an aid in lip-reading. No adverse or pathological side effects have been observed. The patient was the 45th person in Europe to receive an ABI and the first in the Czech Republic.

Surgical treatment strategy for thyroid gland carcinoma nodal metastases.

The authors present their experience with surgical treatment for nodal metastases of thyroid carcinoma based on neck dissections. The specificity of the surgical approach to the lymph nodes was determined by the biologic behavior of each thyroid tumor. Using the available literature on metastases from thyroid tumors, an opinion is supported that surgery for differentiated carcinomas (papillary and follicular neoplasms) can be more conservative and can be safely limited to modified neck dissections. In contrast, a more extended type of selective neck dissection, and only rarely a comprehensive neck dissection, is needed for medullary carcinoma. Because of its rapid spread to distant sites local aggressivity, extirpation of individual lymph nodes or neck dissection is not justified in patients with anaplastic thyroid carcinoma.

[Hydatidiform changes in the chorion]. / Hydatiformní zmeny choria.

Revision of 630 cases of mola enabled a description of morphology in complete hydatid mole, partial hydatid mole, hydropic degeneration and their relation to the origin of trophoblastic disease. A survey covers pathogenesis of molar syndrome, cytogenetic findings and genetic methods for discrimination of complete and partial hydatid mole. To express grade of certainty in diagnostic of the lesions is recommended.

Surgical procedure and results of implantation of the Czech cochlear neuroprosthesis.

A special surgical procedure was developed for the implantation of the Czech single-channel extracochlear neuroprosthesis. The implantation was performed in four adult, postlingually deaf subjects. In one patient a successful reimplantation was performed. The authors assess the implant patients' ability to differentiate changes in simple stimulation signals.

[Post-traumatic stenoses of the larynx and subglottic space]. / Poúrazové stenózy hrtanu a subglotického prostoru.

The authors give the basic principles of the etiopathogenesis of post-traumatic stenoses of the larynx and subglottic space. Therapeutic tactics are briefly described. Three basic types of treatment are illustrated on their own observations.

[Therapeutic and preventive care of trophoblastic disease in Czechoslovakia]. / Lécebne preventivní péce u trofoblastické nemoci v CSSR.

The authors list units of trophoblastic disease and its classification used and elaborated in the Centre for trophoblastic disease. The authors submit detailed information on the organization of diagnostic and therapeutic and preventive care of patients with trophoblastic disease in the CSSR. The authors draw attention to the establishment of a Centre for trophoblastic diseases (CTN) with the statute of a reference department. Reasons for its legalization are given. Its function and structure are described.

[Detection of hCG serum levels in choriocarcinoma using monoclonal antibodies]. / Sérové hladiny hCG u choriokarcinomu sledované pomocí monoklonálních protilátek.

hCG values and those of its alpha- and beta-subunits are assessed in the serum of all patients treated in the Centre of trophoblastic disease. Commercial RIA kits with conventional antibodies are used. There was an opportunity to work with kits of Serono Co. with monoclonal antibodies, the so-called hCG MAIA clone kit which assesses hCG and its beta-subunit. In this IRMA-MAIA system 240 sera of patients with choriocarcinoma were processed. Comparison of hCG values found in the IRMA-MAIA test with values assessed with kits from Kosice revealed the following: 33% of the values in MAIA were higher, 57% were in agreement. 10% of the specimens were MAIA negative, while the Kosice values were low (50-100 i.u./l) and a negative finding was assumed. The authors investigated low (or false positive) hCG values and values obtained during the so-called residual reaction. According to the obtained results in this system of three highly sensitive monoclonal antibodies no cross reaction with LH occurs.

[The present state of implantations of cochlear neuroprostheses worldwide]. / Soucasný stav implantací kochleárních neuroprotéz ve svete.

Cochlear implants provide the patient with acoustic perceptions. The quality of these perceptions varies individually and a technically more complicated implant does not imply a better quality of the achieved acoustic perceptions. The authors submit an account of the present state of cochlear implants on a world-wide scale as well as on the electrophysiological background of implantations, the type of electrodes, processing of the acoustic signal and surgical procedures. Development of the implant is an interdisciplinary problem in which otologists, audiologists, experts in electronics, electrophysiologists, phoniatrists and psychologists participate. The work was implemented during the preparation of the Czech single-channel electrocochlear neuroprosthesis.

[Selection of candidates for cochlear implants]. / Výber kandidátu kochleární implantace.

The successful results of cochlear implantation depend on the correct selection of patients. Suitable candidates for operation are healthy adult, postlingually deaf subjects with a positive promontor test and adequate motivation. In the selection participates an otologist, audiologist, phoniatrist and psychologist. The authors describe their own experience with the selection of hitherto implanted patients and the importance of different tests.

[The surgical approach and results of implantation of the Czech cochlear neuroprosthesis]. / Operacní postup a výsledky implantace ceské kochleární neuroprotézy.

For the implantation of the Czech single-channel extracochlear neuroprosthesis a special surgical procedure was elaborated. The implantation was performed in four adult, postlingually deaf subjects. In one patient a successful reimplantation was performed. The authors evaluate the ability of the patients with implants to differentiate changes of simple stimulating signals.