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Biomedical subjects

M Gersdorff

Publications and source records attributed to M Gersdorff.

At least 55 records · Page 3Linked to original sources
PubMed1995

Fatal encephalopathy after otoneurosurgery procedure with an aluminum-containing biomaterial.

Refractory status epilepticus was observed in two patients who underwent vestibular neurectomy. We investigated the relationship with the use of an aluminum containing bone cement during the procedure. Two patients developed focal and thereafter generalized seizures in the late postoperative period of vestibular neurectomy (respectively after 42 and 35 days). A cement (1 g aluminum-calcium fluorosilicate) was used during the procedure to bridge bone defects. Both patients presented cerebrospinal fluid fistula. Investigations excluded common etiologies, in particular infections, and a toxic origin was suspected. Aluminum concentration was determined repeatedly in serum urine, cerebrospinal fluid and retroauricular fistula. The highest aluminum values were respectively in case 1 and 2, 112 and 63 micrograms/L for the cerebrospinal fluid, 495 and 1440 micrograms/L for the fistula, 4.4 and 4.4 micrograms/L in serum. Desferrioxamine was used as chelating agent and aluminum elimination was analyzed in the urine. Status epilepticus became refractory to intensive care therapy. The patients never recovered normal consciousness. Case 1 died 143 days after the procedure and case 2 at 80 days from brain failure. Brain post-mortem examination was obtained in Case 2. Brain aluminum concentration was 2.5 micrograms/g (wet weight) (0.85 micrograms/g in a control non exposed cadaver). The cement (0.2 g) was incubated in vitro (16 h-37 degrees C) with the cerebrospinal fluid of a control patient (cerebrospinal fluid aluminum 8 micrograms/L): aluminum concentration reached 2750 micrograms/L. A close contact between an aluminum containing cement and the cerebrospinal fluid may have resulted in encephalopathy and fatal status epilepticus in these two patients.

Adult↗
PubMed1995

[Guillain-Barré syndrome and hypacusia].

Guillain-Barré's Syndrome and hearing loss. A child presenting Guillain-Barré's syndrome, together with bilateral hearing loss is presented. The incidence of hypoacusis is unknown. The necessity of behavioural audiometry and electrophysiologic testing is stressed.

Audiometry, Pure-Tone↗
PubMed1995

Myringoplasty: long-term results in adults and children.

This report presents the long-term results 3 years after primary myringoplasties performed with formolized fascia temporalis autografts. The overall closure rate was 87.7% of cases, with improvement in hearing in 67.2% of cases. The best results were achieved with total perforations, and not with partial posterior perforations, contrary to popular opinion. The anterior perforations were the most difficult to close. Anterior angle blunting was avoided by careful technique. Although the results of myringoplasty are clearly better in adults than in children, there is not a determined "frontier age" before which a child may not undergo operation. The state of the middle ear at the time of operation influences surgical outcome: wet ears have a higher rate of perforation, myringitis, and retraction pocket. Medical treatment is recommended prior to surgery in every discharging ear, as a diagnostic method rather than a therapeutic one. If the ear remains wet, chronic otitis media should be considered rather than simple perforation of the eardrum, and a mastoidectomy should be combined with the myringoplasty.

Adolescent↗
PubMed1993

[Bone and cartilage allografts in microsurgery of the ear].

The authors present there experience with bone allografts and costal cartilage allografts in middle ear microsurgery. A drastic selection of the doners and a careful preparation of the grafts avoid the risk of viral transmission to the receiver. The easy available materials can be used for reconstructing the ear drum, the ossicular chain and the tympanic bony wall. With good anatomical and functional results, even at long-term (3 and 4 years).

Bone Transplantation↗
PubMed1993

[The use of glass ionomer cement in otology and in otoneurosurgery].

The use of glass ionomer cement for mastoid obliteration, reconstruction of the external ear canal, closure of the translabyrinthine approach for acoustic neuroma and fixation of a cochlear implant in the temporal bone is described. Preliminary results are encouraging, although some epithelialisation defects may occur in the external ear canal.

Biocompatible Materials↗
PubMed1993

[Etiology and fate of true perilymphatic fistulae].

Perilymphatic fistulas of the round or oval window in a traumatic context or following middle ear surgery or pathology, are reported. Rapid surgical exploration secures the best clinical results.

Diagnosis, Differential↗
PubMed1992

Macroporous biphasic calcium phosphate efficiency in mastoid cavity obliteration: experimental and clinical findings.

Following our previous experimental studies on the performance of macroporous biphasic calcium phosphate (MBCP) in canine mastoid cavities, we used this material in patients requiring surgical intervention. Twenty-two cases were selected, and in eight specific cases a biopsy specimen was taken. Histologic, ultrastructural, and microanalysis studies were performed. This study demonstrates the effectiveness of MBCP implants as bone graft substitutes for mastoid cavity obliteration. Clinical evaluation of the series and histologic and ultrastructural results demonstrated the bioactivity and osteo-conduction of this material, with partial transformation of MBCP granules into lamellar bone after several months.

Adolescent↗
PubMed1992

[Contralateral ear in cholesteatoma].

The authors examine 224 contralateral files of patients suffering from cholesteatoma. They record that the systematic study of the opposite ear can prove to be of interest, given the numerous anomalies found. One ear in two has a contralateral pathology. In 32% of the cases, there is a retraction pocket, and in 14% a cholesteatoma. The mean time for a cholesteatoma to appear from a retraction pocket varies by 24 months in 44% of the cases, thus demonstrating the necessity of examining the opposite ear, as a dynamic evolution exists. Of these pockets, 2% in fact evolved, these statistics, to a true cholesteatoma.

Adolescent↗
PubMed1992

[Primary meningioma of the geniculate ganglion: apropos of a case].

Based on a clinical observation and a literature review, etiologic hypothesis, clinical, radiological and therapeutics characteristics of intratympanic primitive meningioma are described. Those tumors arise from arachnoid cells, some may be carried along the nerve sheath within the Fallopian canal during embryology.

Adult↗
PubMed1992

[Acute vertigo caused by cerebellar vascular accident].

At the beginning, small cerebellar strokes may present only with acute onset of vertigo, unsteadiness and unidirectional nystagmus, like a vestibular neuritis. In some cases, it is associated with tinnitus and hearing disturbance, like an endolymphatic hydrops. Other cases may mimic a benign cupulolithiasis, with only a paroxysmal positioning vertigo. Attention should be focused on transient associated symptoms: headache and blurred vision. One should not wait for classical cerebellar clinical signs: they are subtle and they appear late. Within a few days, the clinical picture will change: vertigo will disappear, while unsteadiness will progress. The electronystagmography confirms the integrity of the vestibular peripheric system. The cerebral CT Scan will show the ischaemic lesions only several days after the onset of the symptoms. A magnetic resonance imaging is far more efficient. Small cerebellar strokes have a good prognosis: complete recovery may be hoped with acetylsalicylic acid treatment and kinesitherapy.

Acute Disease↗
PubMed1992

[Somatosensory evoked potentials in peripheral diseases of the facial nerve: a new investigation method].

In 1988, at the Facial Nerve Congress in Rio de Janeiro, results of facial nerve somatosensory evoked potentials (SEPs) by electrical stimulation of the Ramsay-Hunt zone were presented. In the clinical phase of this work, we have tested 8 normal subjects and 5 patients with unilateral peripheral facial palsy by the SEP method. Significant and reproducible responses were obtained in the normal nerves; general wave-form and different parameters are described: latency of different activities, differences inter and intra-subjects. In one case, we performed a brain mapping by stimulation of the Ramsay-Hunt zone to improve the localization of the different activities and to differentiate them from a possible auditory response to the electrical stimulation. In the pathological nerves, we observed significant changes in the morphology of the cortical waves with regards to the healthy nerves. Detailed results are presented in two cases with a long-term follow-up. We concluded that the electrical stimulation of the Ramsay Hunt zone evokes a cortical response like the electrical stimulation of other cutaneous zones. This response is significantly altered in peripheral facial palsy. Following studies should define the prognostic value of such modifications.

Adult↗
PubMed1992

[Etiology of deafness in children].

A retrospective etiological study of 112 files of deaf children is presented. A prenatal etiology is found in 42.8%, a perinatal in 19.6% and a postnatal in 13.4% of the cases. No cause was suspected in 30.3% of the cases. These results emphasise existing literature.

Chromosome Aberrations↗
PubMed1992

[Value of evoked somatosensory potentials of the facial nerve].

We assessed the somatosensory evoked potentials (SEP) contribution to the evaluation of peripheral pathologies of the facial nerve. SEPs to electrical stimulation of the internal face of the auricle (Ramsay-Hunt zone) were recorded in 8 normal subjects and in 6 patients with unilateral peripheral facial palsy. Significant and reproducible cortical responses were obtained in all normal subjects and to stimulation of the healthy facial nerve in all patients. Brain mapping performed in one normal subject allowed us to locate the different activities on the cortex and to differentiate those from a possible auditory nerve response to electrical stimulation. When stimulating the pathological side, the cortical activities were altered when compared with those obtained by stimulation of the healthy side. In conclusion, the stimulation of the Ramsay-Hunt zone evokes a cortical response like those obtained by somatosensory stimulation of other cutaneous territories. These responses are significantly altered in peripheral facial palsy. Additional studies are needed to establish the prognostic value of these abnormalities.

Adult↗
PubMed1991

[Implantable hearing aids].

The purpose of these hearing aids is to improve the quantity and quality of amplification of the sound wave. Their operating principle is based on the existence of a transducer which transforms the electric signal captured by the microphone into a mechanical, vibrating wave. This transducer can act either directly on the temporal bone by short-circuiting the middle ear (and is then called a bone conduction implant) or directly on the ossicular chain (in which case it is called an ossicular transduction implant). A) There are 2 types of bone conduction implant: the "Audiant Bone Conduction" system of Hough-Vernon (Xomed), where an outside electromagnetic coil sends signals transcutaneously to a magnetic screw embedded on the temporal bone. Bone conduction must be normal. The "Bone Anchored Hearing Aid" (Nobelpharma) where the outside electromagnetic coil sends signals directly to the magnetic screw that is percutaneous. The mean thresholds in bone conduction can reach up to 45 dB. The drawbacks of this system lie in its inaesthetic appearance and the risk of infection. B) With ossicular transduction implants, the transducer may be: either an electromagnetic coil influencing a magnet fixed to the tympanum, on the ossicular chain, or replacing an element of the ossicular chain (these hearing aids are marketed by Richards); or a piezo-electric crystal which produces vibrations when it is subjected to an AC current, and which can be positioned on the stapes (Yanagihara). This system consumes less energy, gives excellent results for the high frequencies, but is more cumbersome.

Bone Conduction↗
PubMed1991

Results of cochlear implants in children.

About 700 children throughout the world have been implanted to date. Placing a cochlear implant represents no particular problem in the child. The incidence of complications is not high, being of about the same proportion as that in the adult. To obtain the best results, the selection of patients must be correct and carried out by a multi-disciplinary team of specialists, while the operated child must be subject to regular and intensive rehabilitation. The results appear to have become more satisfactory since the duration of sensory deprivation has been made shorter. In cases of congenital deafness in prelingual children, implantation should, ideally, take place before the age of six.

Age Factors↗