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Biomedical subjects

M Portmann

Publications and source records attributed to M Portmann.

At least 19 recordsLinked to original sources
PubMed2003

[Invasive cholesteatoma of the old radical mastoidectomy].

OBJECTIVE: The aim of this study is to show the importance of computed tomography scanning (CT) and magnetic resonance imaging (MRI) in ancient radical cavities and to determinate the risk factors of an invasive cholesteatoma recurrency. MATERIAL AND METHOD: We present 4 cases of medial invasion in the petrous bone of a cholesteatoma without specific symptomatology which appeared many years after undergoing radical mastoidectomy for an acquired cholesteatoma. CONCLUSION: The analysis of this series allowed to put in evidence the factors of suspicion of an underlying cholesteatoma. They are: the age, an aural discharge, numerous surgical interventions, immunodeficiency, cholesteatoma in childhood and antecedent of facial nerve palsy. This trial emphasizes the importance of imaging (CT and MRI) in front of an ancient radical cavity which presents one or some of these factors in order to eliminate a recurrence of an invasive cholesteatoma. Let us note that the demand of the patients is sometimes aesthetic or functional.

Adult↗
PubMed1999

[Congenital cholesteatoma of the ear in the child. Clinical, follow-up and therapeutic analysis of a series of 34 cases].

Long a subject of debate, congenital cholesteatomas of the middle ear appear to be a specific clinical entity different from the much more frequent classical acquired cholesteoma. Characteristic features of congenital cholesteatomas are young age at diagnosis, typical peroperative presentation, satisfactory mastoid air cells in almost all cases, and associated congenital malformations, which may involve the otology system or not. Diagnosis is a difficult task due to the long latency period with no clinical manifestations. These congenital cholesteatomas appear to be more aggressive in a mastoid with functioning air cells. Thus open excision does not appear to be appropriate and should be reserved for selected cases. For us, the closed technique with two procedures is more adapted but requires good cooperation with the family. The risk of recurrence is however significant and at least comparable to that of acquired cholesteatomas in children. Follow-up should be persuade as long as possible. Functional results have been encouraging even though ossicular destruction is frequent. The quality of the auditory tube appears to be a determining factor.

Adolescent↗
PubMed1997

[Cholesteatoma of the middle ear in children. Clinical, developing and therapeutic study in a series of 215 consecutive cases].

A retrospective study of 215 cases of cholesteatoma in 199 children operated on from 1985 to 1996 was conducted. Mean age of the children was 9.6 years. Bilateral cholesteatoma was present in 32 cases (8%). The cause was congenital in 32 cases (16%), iatrogenic in 24 cases (11%) and secondary or acquired in 63%. The surgical procedure was a closed technique in 88%, an open technique with or without ossiculoplasty in 10%, and exclusion of the ear using the Rambo technique in exceptional cases (1%). The facial nerve was exposed in 17%. A labyrinth fistula was discovered in 4%, and an intracranial suppuration in only 0.5%. A secondary open procedure was required in 5 cases (2.5%) and secondary exclusion 3 times (1.5%). The ossicular chain was interrupted in 24.2% of the cases and ossicular rehabilitation was performed in 68% of the cases (39% type II, 29% type III), including 49% during the first procedure. At least 2 operations were needed in 62% of the children and 21% had 3 operations. Residual cholesteatomas were observed in 21.5% of all children in the series, 33% in those with a second operation. Recurrence rate was 10%. Mean hearing loss was 28 dB for a mean gain of 4 dB. Post-operative hearing capacity was socially useful in 64% of the cases, including 12% who had normal hearing. Labyrinthization was observed in 15 cases, including 4 cases with total hearing loss. These result are in general agreement with data in the literature. Our strategy is based on a closed procedure for cholesteatomy and systematic re-evaluation at 1 year. The open technique is useful for very extensive lesion on a narrow mastoid, either as second intention procedure or more rarely as a first intention procedure. Management in children differs from that in adults since in adults the destruction has usually progressed further in a mastoid which accepts an open procedure more readily.

Adolescent↗
PubMed1993

Concerning the late diagnosis of certain cerebellopontine angle tumors.

The sensitivity of diagnostic methods for cerebellopontine angle lesions (auditory nerve electrophysiology, computed tomography scanning, magnetic resonance imaging) has increased in recent years. Paradoxically, in our experience this has not led to an increased percentage of tumors detected at an early stage. In 1975 20% of tumors were confined to the internal auditory canal, whereas only 6.6% were intercanalicular in 1988. A detailed analysis of 120 recent cases included first symptoms, time between first symptoms and diagnosis, symptoms at diagnosis, and size of tumor. We conclude the low percentage of intracanalicular tumors in the recent series results from: (1) rapid growth in some cases; (2) slow enlargement of the tumor over a long time without compression of adjacent cranial nerves leading to a paucity of symptoms; (3) misleading clinical pictures, including sudden hearing loss and hydrops; and (4) tumor symptoms masked by unrelated pathologic processes (otosclerosis, presbyacusis, trauma).

Journal Article↗
PubMed1992

Laser micromanipulation in the mouse embryo: a novel approach to zona drilling.

OBJECTIVE: To introduce the use of excimer lasers for penetration of the zona pellucida for micromanipulation purposes. DESIGN: Cryopreserved two-cell mouse embryos were thawed and exposed to the 248-nm line of a krypton fluoride excimer laser (Lambda Physik EMG 202, Goettingen, Germany) creating a 2 to 4-micron opening in the zona pellucida. SETTING: The Laser Ablation Laboratory at DuPont and the in Vitro Fertilization Laboratory at The Medical Center. INTERVENTIONS: The embryos were exposed in either phosphate-buffered solution (PBS) or modified human tubal fluid (HTF) with the laser power varying from 1 to 2 J/cm2 and cultured in Ham's F-10 medium (GIBCO, Grand Island, NY) with 0.4% bovine serum albumin. MAIN OUTCOME MEASURES: The outcome of each experiment was measured by blastocyst formation of laser-exposed embryos as compared with a set of unexposed control embryos handled in a similar fashion. RESULTS: Successful laser penetration of the zona pellucida was achieved using the 248-nm line of a krypton fluoride excimer laser. A higher blastocyst formation was found for embryos exposed in PBS. The higher optical absorption of the modified HTF partially inhibited embryo development. The blastocyst statistics increased 2.5-fold times by reducing the exposure of the embryos to ablation by-products. CONCLUSIONS: The use of a krypton fluoride excimer laser was introduced as a new method to open the zona pellucida of two-cell mouse embryos without interrupting blastocyst formation.

Animals↗
PubMed1992

Problems in alloplastic middle ear reconstruction.

Alloplastic materials have been used in middle ear reconstruction since 1952. Biologically, biomaterials and specifically ceramics can be defined as being bioinert, bioactive or biodegradable; these terms being descriptive of the biochemical response provoked by the material in the host tissue. Various ceramics, carbons and polymers and their reactions have been studied by the author and his colleagues over the past 5 years utilising animal implantation and fibroblast culture studies aligned with experience from clinical usage. The qualities of the ideal alloplastic implant namely: biocompatibility, stabilisation and incorporation, the consistency of the implant and bioactive bonding and the biofunctionality or mechanics, are applied to the materials currently available. No single alloplastic material fulfills all criteria, the problems encountered in relation to the biomaterials are reported. A better understanding of the microstresses, fatigue and microfractures is necessary, before the ideal alloplastic biomaterial becomes available.

Animals↗
PubMed1992

[Congenital cholesteatoma of the middle ear and mastoid. Apropos of 5 cases].

Five cases of congenital cholesteatoma of the middle ear and mastoid as defined by Derlacki's criteria were encountered over a 14 month period. They make up 5% of all cases of cholesteatoma managed over the same period of time. Three were young children and all presented with unilateral hearing loss. One had associated multiple congenital abnormalities of the external and middle ear. Only in one patient was the diagnosis made on initial otoscopic examination and the remainder diagnosed on CTscan, myringotomy and tympanotomy. All were operated on; three by the intact canal wall technique, one by the canal down technique with mastoid cavity obliteration and one by atticotomy with lateral attic wall reconstruction. One patient required a second stage operation for excision of an extension of disease deep to the superior semicircular canal via the middle cranial fossa approach in order to preserve cochlear function. These five cases illustrate the diagnostic pitfalls of this condition in which silent danger lurks behind an intact tympanic membrane.

Adult↗
PubMed1992

[Apropos of the infratemporal pre-auricular approach (its value in the approach to the midline skull base].

The role of the infratemporal pre-auricular pathway to the median base of the skull resides in the fact that it enables very wide access to this region while sparing the facial and auditory nerves. Among the operations performed on the approaches of the base of the skull by their teams, the authors chose a particularly typical observation dealing with the indication of this pathway: a 34-year old male with a giant cholesteatoma of the tip of the petrous bone totally surrounding the internal carotid artery along its entire (intrapetrous) length, from the cervical region to the cavernous sinus, having invaded the clivus and pushed back the brainstem. This lesion is located on the side of the only healthy ear. The patient is completely deaf in the ear on the other side. The operation enabled its complete exeresis while respecting the facial, auditive and vestibular functions.

Adult↗
PubMed1991

[Biomaterials in otology].

Biomaterial may be biological or non-biological in origin. Only the latter will be considered here. Their possible use in otology is threefold: ossiculoplasty: the author recalls the different materials used during the past 30 years. Today, it seems that only certain ceramics are able to compete with auto and homografts. Hydroxylapatite ossicles are a perfectly good alternative; canal wall reconstruction in radical operations: in this context their role appears to be less satisfactory than that of autografts; cavity obliteration: very useful and effective when performed in the correct situation and under certain well-defined technical conditions. After outlining the different materials used in the past 30 years, the author draws upon the experience of his own school to give his personal opinion.

Biocompatible Materials↗