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Biomedical subjects

J Hamzavi

Publications and source records attributed to J Hamzavi.

8 recordsLinked to original sources
PubMed1998

[Function preserving surgical therapy of head-neck tumors with the CO2 laser].

The use of microscopically controlled laser surgery to treat tumors of the upper aerodigestive tract has as a function maintaining form of treatment gained significance. It is an alternative to conventional surgery, which often makes organ removal necessary. We report on our experience with 85 patients who underwent a laser surgical resection of malignomas of the upper aerodigestive tract. The aim of transoral laser surgery is a histologically confirmed radical tumor resection. Tumor resection can be individually adapted according to the tumor extent. An unnecessary resection of cartilage and muscles can be avoided. Provided the appropriate indication is given, laser surgery yields good oncologic and excellent functional results.

Adult↗
PubMed1997

[Initial experiences with the Combi-40 cochlear implant. Surgical aspects].

The rehabilitation of profoundly deaf patients by means of cochlear implants has become a well established form of therapy. Recently, large scale studies have pointed out a variety of surgical complications. A multiplicity of new implant types are each placing more specific demands on the surgeons. Based on the experience with about 160 cochlear implantations in total, the most suitable surgical technique for the implantation of the Combi 40 cochlear implant which has been used in 41 cases is presented. An extended retroauricular incision is made and a caudally based flap is fashioned. The implant bed is drilled 0.5-1 cm behind and above the mastoid cavity. Between the implant bed and the mastoid cavity a groove for the electrodes is drilled cranial of the implant site in the right ear and caudal in the left ear. Access to the scala tympani is gained by a promontory cochleostomy via a posterior tympanotomy of 2x3 mm. Videocontrolled microendoscopes are used to inspect the scala tympani prior to electrode insertion. Electrode insertions depths of up to 30 mm are usually achieved. The electrode and the implant are secured with ionomer-based cement. The described technique has up to now been successfully performed in 30 adults and 11 children.

Adult↗
PubMed1997

[Rehabilitation of patients with hearing loss by cochlear implants].

In the last decade, the rehabilitation of postlingually deaf adults and prelingually deaf children with cochlear implants has been established as a treatment of deafness. The technological development of the implant devices and improvement of the surgical technique have led to a considerable increase of hearing performance during the last years. The postlingually deaf adults are able to use the telephone and may be integrated in their original job. Prelingually deaf children can even visit normal schools after cochlear implantation and hearing rehabilitation training. In order to preoperatively establish the state of the cochlea, radiological diagnosis of the temporal bone is necessary. High resolution computerized tomography imaging of the temporal bone with coronar and axial 1 mm slices and MRI with thin slice technique (three dimensional, T2 weighted turbo-spinecho sequence with 0.7 mm slices) have proved to be valuable according to our experience. Furthermore a postoperative synoptical X-ray, in a modified Chausse III projection, offers good information about the position of the implant and insertion of the stimulating electrode into the cochlea.

Adult↗
PubMed1997

Cochlear implant deep electrode insertion: extent of insertional trauma.

We have recently undertaken deep insertions of the Combi-40 cochlear implant electrode (Med-E1 Corp., Innsbruck, Austria) into apical regions of the scala tympani using a cochleostomy approach. In order to examine the extent of the insertional trauma, 12 fresh human temporal bones were implanted with original Combi-40 electrodes. The specimens were histologically processed with the implants in place by employing a sawing and grinding technique. In most cases, only very discrete distortions of the epithelium of the spiral ligament occurred within the middle cochlear turns. Furthermore, a slight displacement of the basilar membrane caused by the electrode was occasionally seen. However, in 2 cases more severe damage such as basilar membrane rupture and electrode displacement was found. Attempts to insert the electrode beyond the point of first resistance resulted in electrode kinking within the basal cochlear turn with subsequent fracture of the osseous spiral lamina. According to our results, deep electrode insertions do not aggravate the insertional trauma provided no force is applied when resistance is felt.

Cochlea↗
PubMed1996

Auditory fractal random signals: experimental data and clinical application.

In the mammalian primary cochlear afferents, fractals in the postsynaptic bursting behaviour triggered by a constant perisynaptic release of glutamatergic transmitter agonists have been demonstrated. In order to test the validity of fractally coded auditory signal transmission in man, frequency, intensity and temporal resolution tests were performed in cochlear implanted patients. All patients clearly recognized the fractally coded signals transmitted to the cochlear implants. These first results demonstrate evidence for fractally coded auditory signal transmission in man.

Adult↗