RESUMO
UNLABELLED: INDRODUCTION: The regular application of transit time flow measurement in microvascular anastomoses during heart surgery has lead to improvements of the outcome of coronary artery bypass grafts. Our study was meant to discover whether this measurement method was also applicable for evaluation and optimization of microvascular arterial anastomoses of radial forearm flaps. METHODS: In this prospective examination a combining ultrasound imaging and transit time flow measurement device (VeriQ, MediStim) was used during surgery to assess anastomotic quality of 15 radial forearm flaps. Pulsatility index (PI) and mean blood flow were measured immediately after opening the arterial anastomosis as well as 15 min afterwards. Furthermore, application time and description of handling were recorded seperately for every assessment. RESULTS: Mean blood flow immediately after opening the anastomosis and 15 min later were 3.9 and 3.4 ml/min resepectively showing no statistically significant difference (p=0.96). There was no significance in the increase of pulsatility index from 22.1 to 27.2 (p=0.09) during the same time range, either. Due to measurement results showing atypical pulse curves in 2 cases decision for surgical revision of the anastomoses was made. All forearm flaps showed good vascularisation during follow-up. Time for device set up, probe placement and measurements was about 20 min. Handling was described to be uncomplicated without exception. There were no noteworthy problems. CONCLUSION: Transit time flow measurement contributes to the improvement of anastomotic quality and therefore to the overall outcome of radial forearm flaps. The examined measurement method provides objective results and is useful for documentation purposes.
Assuntos
Anastomose Cirúrgica , Velocidade do Fluxo Sanguíneo , Volume Sanguíneo , Retalhos de Tecido Biológico/irrigação sanguínea , Retalhos de Tecido Biológico/cirurgia , Microcirurgia , Neoplasias Otorrinolaringológicas/cirurgia , Complicações Pós-Operatórias/diagnóstico , Complicações Pós-Operatórias/fisiopatologia , Análise de Onda de Pulso , Ultrassonografia/instrumentação , Humanos , Neoplasias Hipofaríngeas/cirurgia , Masculino , Pessoa de Meia-Idade , Neoplasias Orofaríngeas/cirurgia , Complicações Pós-Operatórias/cirurgia , Estudos Prospectivos , ReoperaçãoRESUMO
Atypical mycobacteriosis is a rare cause of cervical lymphadenitis that most frequently affects immunoincompetent children between the ages of 12 months and 5 years. The typical clinical manifestation is a painless unilateral cervical mass. The nonspecific clinical symptoms and laboratory parameters complicate diagnosis and, therefore, therapeutic management. Various therapeutic options, including surgery, antimycobacterial drug therapy and wait-and-scan approaches are discussed in the literature. Complete surgical excision has become the established treatment of choice. However, controlled randomized studies that clearly demonstrate the benefits of a particular type of therapy are lacking.
Assuntos
Antituberculosos/uso terapêutico , Excisão de Linfonodo/métodos , Tuberculose dos Linfonodos/diagnóstico , Tuberculose dos Linfonodos/terapia , Pré-Escolar , Terapia Combinada , Feminino , Humanos , Lactente , Imageamento por Ressonância Magnética/métodos , Masculino , Pescoço/patologia , Fatores de Risco , Tuberculose dos Linfonodos/microbiologiaRESUMO
BACKGROUND: The incidence of soft tissue tumors of the head and neck region is low: 300 and 3 in 100,000 for benign and malignant tumors, respectively. However, sarcomas particularly show a wide variety of different histological subtypes. This article provides an overview of the soft tissue tumors of the head and neck region treated in the authors' institution. MATERIAL AND METHODS: This is a retrospective study including 106 patients treated between 2002 and 2010 due to a soft tissue tumor. Tumor- and patient-specific data were collected (benign/malignant tumor, location, TNM classification, therapy, R classification, grade). RESULTS: In total, 77 benign tumors, 5 of intermediate benign/malignant nature and 24 sarcomas (with 7 different subtypes) were identified. Whereas the benign and intermediate tumors were treated by surgical removal, in 21 of the 24 sarcomas, treatment comprised a multimodal therapy regimen including radio- and/or chemotherapy. CONCLUSION: Whereas benign tumors can be successfully treated by surgical resection, there is no uniform therapy regimen for sarcomas due to the variety of different histological subtypes. Only case-specific interdisciplinary disease management can offer good perspectives for therapeutic success.
Assuntos
Neoplasias de Cabeça e Pescoço/epidemiologia , Neoplasias de Cabeça e Pescoço/terapia , Neoplasias de Tecidos Moles/epidemiologia , Neoplasias de Tecidos Moles/terapia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Alemanha/epidemiologia , Neoplasias de Cabeça e Pescoço/diagnóstico , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , Neoplasias de Tecidos Moles/diagnóstico , Resultado do Tratamento , Adulto JovemRESUMO
INTRODUCTION AND METHODS: Epiphora, which leads to blurry vision, is the leading symptom for intra- and/or postsaccal lacrimal duct stenosis. Due to the anatomy of the tear duct system, which lies between the fields of ophthalmology and otorhinolaryngology, and due to newly available techniques in interventional radiology to diagnose and treat patients with intra- and postsaccal lacrimal duct stenosis, various methods for diagnosis and treatment are available. We report the results of 107 patients who underwent endonasal dacryocystorhinostomy (DCR) between 2005 and 2011. RESULTS: Prior to the DCR, dacryocystography was performed in 95 of the 107 patients. In 68 of these 95 cases, balloon dilatation was unsuccessful. Histological examination of 64 patients showed chronic inflammation in 61 patients, non-Hodgkin's lymphoma was diagnosed in 2 patients and aspergilloma in1 patient. Over a follow-up time of 6 months to a maximum of 7 years we revised 15 of 107 patients, due to reocclusion after removal of the stent. None of these patients showed recurrence of epiphora. DISCUSSION: In comparison to transcutaneous DCR, endonasal DCR has certain benefits: it is less invasive, no visible scars occur because of the endonasal approach, and the function of the lacrimal pump remains uneffected. Furthermore, the possibility of co-treatment of endonasal pathologies during DCR exists. We observed no serious adverse events in our study group and the success rate was similar to other studies.
Assuntos
Dacriocistorinostomia/métodos , Dacriocistorinostomia/estatística & dados numéricos , Complicações Pós-Operatórias/epidemiologia , Transtornos da Visão/epidemiologia , Transtornos da Visão/prevenção & controle , Adulto , Comorbidade , Feminino , Alemanha , Humanos , Obstrução dos Ductos Lacrimais/diagnóstico , Obstrução dos Ductos Lacrimais/epidemiologia , Masculino , Pessoa de Meia-Idade , Equipe de Assistência ao Paciente/estatística & dados numéricos , Prevalência , Fatores de Risco , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: Quality of life is extraordinary affected by malignant tumors of the head and neck region as functions of social interaction are disturbed. MATERIALS AND METHODS: The influence of surgical treatment and postoperative radio(chemo)therapy (RCT) on the quality of life was studied in patients with head and neck cancer. Twenty patients treated with curative intention completed the questionnaires EORTC QLQ-C30 and EORTC QLQ-H&N35 at three time points. RESULTS: In most questions, patients reported poorer quality of life after RCT compared to postoperatively. Most of these differences were not significant. However, global quality of life and overall health was significantly worse after RCT as compared to postoperatively. CONCLUSION: Both operation and postoperative RCT, lead to decreased quality of life in patients with a head and neck cancer. In comparison, RCT seems to have a more pronounced effect on the quality of life than operative therapy.
Assuntos
Quimiorradioterapia/estatística & dados numéricos , Neoplasias de Cabeça e Pescoço/epidemiologia , Neoplasias de Cabeça e Pescoço/terapia , Procedimentos Cirúrgicos Otorrinolaringológicos/estatística & dados numéricos , Qualidade de Vida , Adulto , Idoso , Feminino , Alemanha/epidemiologia , Neoplasias de Cabeça e Pescoço/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Resultado do TratamentoRESUMO
The capability of the adult brain to generate new hippocampal neurons after brain insults like stroke is decreasing during the aging process. Recent evidence further indicates that the proliferative properties of the precursor cells change in the aged brain. We therefore analyzed the early proliferative response of distinct precursor cell populations in the subgranular zone of the dentate gyrus in 3 and 16 months old transgenic nestin-green-fluorescent protein mice 4 days after ischemic cortical infarcts. A detailed immunocytochemical analysis of proliferating precursors revealed a significant infarct-induced activation of the earliest radial glia-like precursor cells (type 1 cells) and the more differentiated precursor cell subtypes (type 2b cells) in young mice. In contrast the proliferation of early neuronal precursor cells (type 2a cells) was stimulated in the aged brain. Additional long-term experiments further demonstrated that this differential proliferative response of distinct precursor cells is associated with an enhanced number of newborn neurons in the young DG after stroke whereas this increase in neurogenesis was absent in the aged brain. However, our study demonstrates that even precursor cells in the aged hippocampus possess the ability to respond to remote cortical infarcts.
Assuntos
Envelhecimento/patologia , Acidente Vascular Cerebral/patologia , Animais , Proliferação de Células , Sobrevivência Celular , Infarto Cerebral/patologia , Giro Denteado/patologia , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Filamentos Intermediários/genética , Masculino , Camundongos , Camundongos Transgênicos , Proteínas do Tecido Nervoso/genética , Nestina , Células-Tronco Neurais/patologia , Neurogênese , Neuroglia/patologia , Neurônios/patologiaRESUMO
Castleman's disease, also called angiofollicular lymph node hyperplasia or benign giant lymphoma, is a rare lymphoproliferative disorder of unknown etiology. Three histologic subtypes are described--hyaline vascular (80-90%), plasma cell (10-20%), and mixed (rare). In the clinical setting, localized and multicentric entities are distinguished. Due to the lack of tumor-specific clinical, biochemical, and radiological features, final diagnosis of Castleman's disease depends on histopathology. Surgical tumor resection is the treatment of choice for localized disease. Prognosis is good, and adjuvant therapy is not required. Therefore, early invasive removal and histopathological differentiation from neoplasia is mandatory. In contrast, the prognosis for multicentric Castleman's disease remains poor even if multimodal treatment regimens are employed. Major clinical symptoms, histology, and therapy are summarized, and the disease characteristics are highlighted presenting the case of an 11-year-old girl. On admission, the patient complained of a painless pharyngeal tumor mass and ipsilateral lymph node swelling. Magnetic resonance imaging revealed a parapharyngeal contrast-enhancing lesion extending from the hypopharynx to the skull base without signs of infiltration and accompanied by ipsilateral lymph node hyperplasia of the neck. Laboratory test results were within normal limits. After tumor resection, histopathological examination, and clinical staging, localized Castleman's disease was diagnosed (hyaline vascular subtype).
Assuntos
Hiperplasia do Linfonodo Gigante/diagnóstico , Hiperplasia do Linfonodo Gigante/cirurgia , Otolaringologia/métodos , Neoplasias Faríngeas/diagnóstico , Neoplasias Faríngeas/cirurgia , Criança , Diagnóstico Diferencial , Feminino , HumanosRESUMO
Congenital high airway obstruction syndrome (CHAOS) from laryngeal atresia bears a poor prognosis for hydropic fetuses owing to cardiac failure. We attempted percutaneous fetoscopic and ultrasound-guided tracheal decompression in a hydropic human fetus with CHAOS associated with Fraser syndrome. Percutaneous fetoscopic and ultrasound-guided tracheal decompression was performed using three trocars under general materno-fetal anesthesia at 19 + 5 weeks of gestation. Abnormal fetoplacental blood flow normalized within hours as a result of the intervention. Furthermore, a normalization of lung : heart size and lung echogenicity was observed within days. Resolution of hydrops was complete within 3 weeks. Premature rupture of membranes and premature contractions prompted emergency delivery of the fetus by ex-utero intrapartum treatment (EXIT) at 28 + 2 weeks of gestation. Following delivery, the lungs could be ventilated at low pressures and ambient oxygen concentration. Weaning from ventilation was achieved at 18 days of postnatal life. Our experience indicated that percutaneous fetoscopic and ultrasound-guided decompression of the fetal trachea is feasible and may permit normalization of hemodynamics in hydropic human fetuses with CHAOS from laryngeal atresia. The procedure may also result in normalization of heart : lung size and provide the time needed to regain the function of the overstretched diaphragm in this grave fetal condition.
Assuntos
Obstrução das Vias Respiratórias/cirurgia , Doenças Fetais/cirurgia , Laringe/anormalidades , Ultrassonografia Pré-Natal/métodos , Descompressão Cirúrgica , Feminino , Fetoscopia/métodos , Humanos , Gravidez , Síndrome , Ultrassonografia de Intervenção/métodosRESUMO
For reconstruction in the head-neck region, either pedicled or free flaps can be used depending on the site of origin and the place of reconstruction. Pedicled flaps have definite limitations, therefore, free transplants are becoming continuously more popular. Today, microvascular reanastomosed transplants are those most commonly used in reconstructive head-neck surgery. In this contribution, we present and explain the most important types of flaps and their indications.
Assuntos
Cabeça/cirurgia , Pescoço/cirurgia , Procedimentos de Cirurgia Plástica/instrumentação , Procedimentos de Cirurgia Plástica/métodos , Retalhos Cirúrgicos , Cervicoplastia/instrumentação , Cervicoplastia/métodos , Humanos , Guias de Prática Clínica como Assunto , Padrões de Prática Médica , Resultado do TratamentoRESUMO
BACKGROUND: After pharyngolaryngectomy reconstructive procedures of the upper digestive tract are necessary. Since the introduction of microvascular tissue transplantation jejunal loops proved to be a versatile transplant. Nevertheless it has some disadvantages as i. e. the increased donor morbidity, a rather high sensitivity to hypoxia and the tendency of shrinkage and formation of stenosis. METHOD: We perform the reconstruction of the hypopharynx with the radial forearm flap. The fasciocutaneous flap is harvested on the radial artery in a size of 12 x 6 cm in average and is sutured U-shaped paramedian to the prevertebral fascia. In addition the posterior wall of the oesophagus and the oropharynx have to be adapted to the prevertebral fascia. RESULTS: Between 1997 and 2001 we performed these reconstructions in 20 patients. In one case we found a complete flap necrosis, which required secondary reconstruction with a pectoralis major flap. In 2 patients we saw a stenosis at the junction to the oesophagus, which was treated by revision surgery and bougienage. In 18 patients swallowing was regular. 6 patients were able to learn oesophageal speech. CONCLUSION: The radial forearm flap in its U-shaped transposition to the prevertebral fascia represents a functionally good reconstructive procedure for the hypopharynx.
Assuntos
Neoplasias Esofágicas/cirurgia , Neoplasias Hipofaríngeas/cirurgia , Hipofaringe/cirurgia , Laringectomia , Microcirurgia/métodos , Faringectomia , Retalhos Cirúrgicos , Neoplasias Esofágicas/patologia , Estenose Esofágica/cirurgia , Seguimentos , Humanos , Neoplasias Hipofaríngeas/patologia , Hipofaringe/patologia , Metástase Linfática , Estadiamento de Neoplasias , Complicações Pós-Operatórias/cirurgia , Reoperação , Voz Esofágica , Técnicas de SuturaRESUMO
OBJECTIVE: To analyze the advantages in safety and precision of biopsies of the petrous apex and petroclival region using open magnetic resonance imaging (MRI). SETTING: The University of Leipzig Medical Center. PATIENTS: Biopsies were taken in 13 patients with tumors of the petrous apex and petroclival region. INTERVENTION: With the patient in the 0.5-T intraoperative MRI system (Signa SP; General Electric Medical Systems, Boston, MA, U.S.A.), biopsies were taken from the petrous apex and the petroclival region under imaging control by transseptal, transsphenoidal access. The region of interest was approached with a virtual pointer (Flashpoint Position Encoder; Image Guided Technologies, U.S.A.) and marked with a gadolinium-filled pointer. RESULTS: In all patients, the authors obtained enough tissue for histologic study, which also proved to be the suspected tumor. One patient had a bone cyst, another had a malignant lymphoma, and another two a cholesterol granuloma originating from the petrous apex. Three other patients had metastases (carcinoma of the breast, bronchial carcinoma, and unknown origin). Three patients had a meningioma, and another three a chordoma. The authors did not see any postoperative complications. CONCLUSIONS: In the authors' experience, the transsphenoidal access is favorable for approaching and sampling lesions of the petrous apex and the petroclival region. This route, however, is disadvantageous because the course of the internal carotid artery and the brainstem narrow the surgical space to the petrous apex. Open MRI in these cases is very useful because it allows a safe approach to the tumor by navigation and by visualizing the anatomic structures in real-time imaging.
Assuntos
Fossa Craniana Posterior/patologia , Imageamento por Ressonância Magnética , Osso Petroso/patologia , Adulto , Idoso , Biópsia/instrumentação , Criança , Fossa Craniana Posterior/cirurgia , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osso Petroso/cirurgiaRESUMO
Magnetic resonance imaging (MRI) allows excellent tissue characterization in the area of the petroclival region and can depict lesions not visualized with ultrasound or computed tomography (CT). The aim of this study was to demonstrate the clinical feasibility and utility of an interactive MR-guidance system to target and biopsy tumors in the petroclival region. MRI-guided biopsies of 10 patients with tumors in the clivus and petrous apex were performed in an open 0.5-T MR system. Lesions were targeted through a transsphenoidal or transnasal approach. Imaging during biopsies was achieved by a combination of standard and interactive mode. T1-weighted spin-echo, T2-weighted fast spin-echo (FSE), and three-dimensional T1-weighted gradient-echo (GRE) scans (standard mode) were selected to provide optimal tissue characterization for both the lesion and surrounding structures and varied according to the anatomic site. For interactive imaging, T1-weighted GRE and T2-weighted FSE sequences were used. We performed MRI-guided transsphenoidal biopsies in 10 patients who had lesions identified by CT (n = 5) and/or MRI (n = 10). The indications for biopsies were to differentiate between suspected malignant processes (n = 4 ) and benign processes (n = 6). Lesions adjacent to structures like the internal carotid artery were accurately targeted in particular. All biopsies were performed successfully and were the basis for selection of further treatment. No complications occurred during the procedures. An open MR system allows interactive control of biopsies in the area of the petroclival region, providing maximum patient safety and diagnostic accuracy not possible in other systems. The advantages of MRI tissue characterization are combined with an interactive, one-step method of localization and targeting, as well as tissue sampling. J. Magn. Reson. Imaging 2001;13:3-11.
Assuntos
Biópsia por Agulha/métodos , Neoplasias Encefálicas/patologia , Imageamento por Ressonância Magnética , Neoplasias da Base do Crânio/patologia , Fossa Craniana Posterior , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osso Petroso , Radiologia IntervencionistaRESUMO
A 74-year-old man with diabetes mellitus type II, retinopathy and polyneuropathy suffered from exophthalmus, ptosis and diplopia. Magnetic resonance imaging and computer tomography showed a space-occupying process in the right orbital apex. An extranasal ethmoidectomy accompanied by an orbitotomia revealed the presence of septated hyphae. Aspergillus fumigatus was grown from the tissue. After surgical removal of the fungal masses, therapy with amphotericin B (1 mg kg(-1) body weight) plus itraconazole (Sempera, 200 mg per day) over 6 weeks was initiated. Five months later the patient's condition deteriorated again, with vomiting, nausea and pain behind the right eye plus increasing exophthalmus. Antifungal therapy was started again with amphotericin B and 5-fluorocytosine. Neutropenia did not occur. The patient became somnolent and deteriorated, a meningitis was suggested. Aspergillus antigen (titre 1:2, Pastorex) was detected in liquor. Anti-Aspergillus antibodies were not detectable. Both the right eye and retrobulbar fungal masses were eradicated by means of an exenteratio bulbi et orbitae. However, renal insufficiency and an apallic syndrome developed and the patient died. At autopsy, a mycotic aneurysm of the arteria carotis interna dextra was detected. The mycotic vasculitis of this aneurysm had caused a rupture of the blood vessel followed by a massive subarachnoidal haemorrhage. In addition, severe mycotic sphenoidal sinusitis and aspergillosis of the right orbit were seen, which had led to a bifrontal meningitis.
Assuntos
Aneurisma Infectado/microbiologia , Arterite/microbiologia , Aspergilose/complicações , Aspergillus fumigatus , Diabetes Mellitus Tipo 2/complicações , Meningite Fúngica/complicações , Doenças Orbitárias/complicações , Idoso , Antifúngicos/uso terapêutico , Antígenos de Fungos/líquido cefalorraquidiano , Aspergilose/tratamento farmacológico , Aspergillus fumigatus/imunologia , Aspergillus fumigatus/isolamento & purificação , Quimioterapia Combinada , Evolução Fatal , Seguimentos , Humanos , Imageamento por Ressonância Magnética , Masculino , Meningite Fúngica/líquido cefalorraquidiano , Meningite Fúngica/patologia , Doenças Orbitárias/diagnóstico , Tomografia Computadorizada por Raios XRESUMO
Intraoperative imaging in head and neck surgery is a useful tool in many situations. In addition to being helpful for intraoperative orientation, real-time imaging enables visualization of the progress of surgery and the completeness of tumor resection. Regions in the head and neck to which access is difficult, and which therefore have a high incidence of morbidity and risk for the patient, can be approached more easily and safely in an open MRI than in a conventional way. Interventions in the open MRI (Signa SP, 0.5 Tesla) were performed with nonmagnetic instruments and an MR-safe microscope. For intraoperative navigation, the integrated FlashPoint system is helpful, because it allows targeting of the tumor by a calculated virtual line. T1W spin-echo, T2W fast spin-echo, and 3D T1W gradient-echo sequences were used for high-resolution imaging. Real-time imaging is achieved by fast multiplanar spoiled gradient-echo sequences or T2 single-shot fast spin-echo sequences. From 1996 to the present, we biopsied 17 petroclival tumors, performed paranasal sinus surgery in five cases, biopsied two neck masses, and inserted tubes for brachytherapy in 12 cases. No complications were observed. In all surgical procedures, a good resolution was obtained with MRI, especially for soft-tissue structures. The tumor could be targeted exactly, and all specimens revealed the relevant histology. In paranasal sinus surgery, however, the success rate was lower because it was difficult to distinguish blood from pathologic tissue. The insertion of tubes for brachytherapy was successful in all cases. It was possible to apply the tubes parallel to each other, 1 cm apart. Relevant biopsies could be taken of both neck masses. The indications for the use of open MRI in otorhinolaryngology are biopsies of tumors in regions that are difficult to approach, such as the petrous apex and petroclival region, the parapharyngeal space, and the orbit. Furthermore, the open MRI can be useful in paranasal sinus surgery, in the evaluation of tissue resection, and in the detection of the anatomy of delicate structures such as the internal carotid artery, the skull base, and the orbit. In addition, active navigation in the open MRI is possible with the integrated FlashPoint system. The advantage over conventional navigation systems lies in the possibility of real-time imaging, which allows detection of tissue changes occurring during the procedure.
Assuntos
Imageamento por Ressonância Magnética/instrumentação , Neoplasias Otorrinolaringológicas/cirurgia , Biópsia/instrumentação , Humanos , Imageamento por Ressonância Magnética/normas , Neoplasias Otorrinolaringológicas/diagnóstico , Neoplasias Otorrinolaringológicas/patologia , Osso Petroso/patologiaRESUMO
We have recently developed an implantable piezoelectric hearing aid transducer that is suitable for implantation in patients with sensorineural hearing loss. The transducer does not transmit sound but conducts micromechanical vibrations to the cochlea. In ten cat ears we investigated the efficiency of the implantable transducer with respect to the direct transfer of vibrations within the audible frequency range via the ossicles to the cochlea or directly into the vestibule. The acoustically evoked brainstem potential (ABR) threshold was determined prior to implantation, and the middle ear was then opened and the piezoelectric transducer coupled to the ossicles or to the perilymph. Acoustically evoked brainstem potentials were recorded following stimulation at the umbo, long process of the incus, stapes head, stapes foot plate, and in the vestibulum. Comparisons of the acoustically and mechanically evoked thresholds revealed a good correlation of the two stimulation levels. An electrical transducer voltage of 1 V(RMS) produced equivalent sound pressure levels (SPL) of 100-128 dB at the tympanic membrane. To assess the hearing we compared stimulus-dependent latencies of the early potentials (peaks P1-P5) and thresholds. This evaluation was based on four ears with normal hearing in which the piezoelectric transducer was coupled to the long process of the incus. The mean values of the latencies and their scattering range correlated extremely well in the two stimulation modes. They were nearly identical when the equivalent SPL of 100 dB was assigned to the maximally applied electrical level of 0 dB. These in vitro and in vivo findings demonstrate that the characteristics of the transducer warrant its development further from the prototype stage to become a component of an implantable hearing device for patients with sensorineural hearing loss.
Assuntos
Auxiliares de Audição , Implantes Experimentais , Estimulação Acústica , Animais , Audiometria , Gatos , Potenciais Evocados Auditivos do Tronco Encefálico , Masculino , TransdutoresRESUMO
To evaluate occurrences of reinnervation and degeneration, the portio auricularis of the zygomatic muscle was reinnervated (either primary or secondary reinnervation) with an interval of 6 weeks, using a neuromuscular transplant of the sternohyoid muscle, which was left at the ansa hypoglossi. Histological examination was performed 6 and 12 weeks later. Enzymatic stains for myofibrillar ATPase were used for differentiation of muscle fibre types. Histomorphological features of denervation and reinnervation were analysed. Six weeks after denervation and primary neuromuscular transplantation, type grouping in regions close to the transplanted muscle were detectable as signs of reinnervation. After a period of 12 weeks, the progressing reinnervation was proved by type grouping in distal areas of the muscle far from the area of transplantation. At the same time, differentiation of fibre typing in the type grouping areas increased. All denervated and reinnervated muscles had pathological variations of fibre diameter. Primary reinnervated muscles showed tendency of normalization in variation of diameter. Compared with primary reinnervated muscles, secondary reinnervated muscles with an interval of 6 weeks showed pronounced polymorphology of fibres and a high pathological increase of the variation of fibre diameters. The interfascicular space was significantly spread. The tendency of reinnervation with incidence of fibre type grouping was comparable to primary reinnervated muscles and also occurred 6 weeks after transplantation.
Assuntos
Músculos Faciais/inervação , Paralisia Facial/cirurgia , Regeneração Nervosa/fisiologia , Transferência de Nervo/métodos , Animais , Paralisia Facial/patologia , Paralisia Facial/fisiopatologia , Nervo Hipoglosso/patologia , Nervo Hipoglosso/fisiopatologia , Denervação Muscular , Fibras Nervosas/patologia , Fibras Nervosas/fisiologia , Junção Neuromuscular/patologia , Junção Neuromuscular/fisiopatologia , Complicações Pós-Operatórias/patologia , Complicações Pós-Operatórias/fisiopatologia , CoelhosRESUMO
OBJECTIVE: For the surgical treatment of patients with moderate and severe sensorineural hearing loss, the authors have developed a totally implantable hearing device, the totally integrated cochlea amplifier (TICA). To evaluate the effectiveness of transducer and microphone of this device, three separate human studies were conducted. STUDY DESIGN: The first study using transducer prototypes involved self experiments in investigators with normal hearing. The second study used the transducer prototypes in patients with hearing loss, and the third study involved the temporary implantation of the final transducer prototype and microphone in patients undergoing otologic surgery. PATIENTS: In routine middle ear surgery, transducer prototypes were coupled to the ossicular chain of 28 patients. In addition to the transducer, in 5 patients the microphone was placed beneath the skin of the auditory canal, allowing the skin to cover the microphone membrane completely. RESULTS: The piezoelectric transducer reached an equivalent sound pressure level of 145 dB SPL < or =10 kHz. The dynamics for music reached 32 dB, which was identical with the results of the preoperative investigations using high-fidelity headsets (33 dB). The low nonlinear distortions of <0.1% and the frequency range of 10 kHz are reflected in the positive evaluation of the sound quality by 84% of the patients involved. When phonetically balanced speech material and music were presented under free field conditions at a sound level of 65 dB SPL, understanding of the phonetically balanced speech material was 100%. Most patients judged the presentations of music as clear and undistorted with all broadband components. CONCLUSIONS: Data in humans on the performance of the two main components of the TICA implant, the transducer and the microphone, are reported.