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Biomedical subjects

G Lamas

Publications and source records attributed to G Lamas.

At least 55 records · Page 3Linked to original sources
PubMed1992

Visual improvement after transethmoid-sphenoid decompression in optic nerve injuries.

Transethmoid-sphenoid decompression has been performed on 11 patients with indirect optic nerve injury. Visual improvement occurred in 8 patients, including 4 patients with initial total blindness. Optic neuropathy improved even when there was a long interval, up to 92 days, between trauma and decompression. There is still controversy about the treatment of traumatic optic neuropathy. Our results suggest that surgery can be helpful in the management of this condition. Transethmoid-sphenoid optic nerve decompression is a minimally invasive procedure that gave, in this series, satisfactory results with low morbidity.

Adolescent↗
PubMed1992

[Surgical decompression of the optic nerve in intracanal injuries. Indications and results].

Fifteen patients with traumatic optic neuropathy (anatomical section excluded) underwent surgical anterior decompression of the optic nerve, via the trans ethmoid-sphenoid approach. Improvement of visual function assessed by visual acuity and visual field measurements, was obtained in 10 patients. Results remained stable for a follow-up period of at least 6 months. There was a delay of several weeks before improvement in some of the patients. Thus a long follow-up period seems recommended. Trans ethmoid-sphenoid optic nerve decompression is a reliable procedure with low morbidity, and represents a promising therapy for indirect injuries of the optic nerve.

Adolescent↗
PubMed1992

[X-ray computed tomography in surgical indication of physiological section of the optic nerve. Apropos of 15 cases].

Optic nerve trauma induces loss of vision and absence of direct pupillary light reflex. Persistence of consensual pupillary light reflex excludes anatomical section. Trans ethmoidal-sphenoidal decompression relieves the optic nerve and allows an improvement of visual function. Ten patients among 15 surgical decompressions recovered visual function. There is a good correlation between improvement and the release of an anatomical nerve compression. Recognition of direct or indirect computed tomographic signs of optic nerve compression are essential in the surgical indications. The prognosis post-surgical improvement is dependent on the sensitivity of computed tomography scan.

Craniocerebral Trauma↗
PubMed1991

[Chronic maxillary sinusitis of dental origin and nasosinusal aspergillosis. How to manage intrasinusal foreign bodies?].

About a series of 33 patients operated in the ENT Depart. Prof. Soudant-La Pitié-Salpêtrière Hospital-Paris. Any emphasis was put on 11 cases of aspergillosis sinusitis. Most of the time, clinical signs are non specific. But X rays studies are of great help for the diagnosis. Treatment of chronic sinusitis of dental origin, particularly aspergillosis, remains surgical: caldwell-luc operation or endonasal approach. As a conclusion, the authors suggest systematic removal of all intrasinusal foreign body.

Adult↗
PubMed1990

Estimates of selection and gene flow from measures of cline width and linkage disequilibrium in heliconius hybrid zones.

Hybrid zones can yield estimates of natural selection and gene flow. The width of a cline in gene frequency is approximately proportional to gene flow (sigma) divided by the square root of per-locus selection (square root of s). Gene flow also causes gametic correlations (linkage disequilibria) between genes that differ across hybrid zones. Correlations are stronger when the hybrid zone is narrow, and rise to a maximum roughly equal to s. Thus cline width and gametic correlations combine to give estimates of gene flow and selection. These indirect measures of sigma and s are especially useful because they can be made from collections, and require no field experiments. The method was applied to hybrid zones between color pattern races in a pair of Peruvian Heliconius butterfly species. The species are Müllerian mimics of one another, and both show the same changes in warning color pattern across their respective hybrid zones. The expectations of cline width and gametic correlation were generated using simulations of clines stabilized by strong frequency-dependent selection. In the hybrid zone in Heliconius erato, clines at three major color pattern loci were between 8.5 and 10.2 km wide, and the pairwise gametic correlations peaked at R approximately 0.35. These measures suggest that s approximately 0.23 per locus, and that sigma approximately 2.6 km. In erato, the shapes of the clines agreed with that expected on the basis of dominance. Heliconius melpomene has a nearly coincident hybrid zone. In this species, cline widths at four major color pattern loci varied between 11.7 and 13.4 km. Pairwise gametic correlations peaked near R approximately 1.00 for tightly linked genes, and at R approximately 0.40 for unlinked genes, giving s approximately 0.25 per locus and sigma approximately 3.7 km. In melpomene, cline shapes did not perfectly fit theoretical shapes based on dominance; this deviation might be explained by long-distance migration and/or strong epistasis. Compared with erato, sample sizes in melpomene are lower and the genetics of its color patterns are less well understood. In spite of these problems, selection and gene flow are clearly of the same order of magnitude in the two species. The relatively high per locus selection coefficients agree with "major gene" theories for the evolution of Müllerian mimicry, but the genetic architecture of the color patterns does not. These results show that the genetics and evolution of mimicry are still only sketchily understood.

Animals↗
PubMed1990

[The temporomandibular joint: anatomy, physiology, clinical review].

The temporomandibular joint (TM joint) is a synovial joint with two condylar surfaces and an intra-articular cartilaginous disc. Its development has two origins. Its physiology is complex and intimately related to dental occlusion, which is why we talk about the temporomandibular and dental joint. Recent neurophysiological data allow a better approach to TM joint dysfunction. The lateral pterygoid muscle plays decisive role in the pathogenesis of TM joint dysfunction.

Humans↗
PubMed1990

[Neurinoma of the 8th cranial nerve. Surgical indications in neurofibromatosis].

There are two types of neurofibromatosis, i.e. peripheral neurofibromatosis (type 1) and central neurofibromatosis (type 2). Neurinomas of the acoustic nerve are basically seen in central neurofibromatosis, in which case they are generally bilateral. Surgical indications for neurinoma are rare and 5 patients will be discussed: 2 of these underwent an operation on the neurinoma by the posterior route on several occasions, while 1 patient was operated by the trans-labyrinth route. Nuclear magnetic resonance remains the best means of monitoring.

Adult↗
PubMed1990

[Severe lesions of the petrous bone caused by pseudomonas aeruginosa].

Pseudomonas aeruginosa is often isolated in infections of the ear cleft. In some circumstances, this organism can cause serious petrous or peri-petrous lesions. Two pictures are seen: Malignant external otitis with severe headaches, signs of external otitis, and usually pseudomonas aeruginosa is isolated. This is usually seen in an elderly diabetic patient. Nerve paralysis is the main risk. The other complications, very grave in the past, are rare nowadays with the use of selective antibiotic treatment. Pseudomonas aeruginosa is also the causative organism in extensive osteitis of the skull base. Diagnostic problems are seen in case of specific infections or tumoral lesions. The treatment includes the same medications as for the malignant external otitis, as well as complete surgical excision.

Aged↗
PubMed1990

[The value of radiotherapy in the treatment of tympano-jugulare chemodectoma. Apropos of 18 cases].

Surgery is the standard treatment of tympano-jugular chemodectomas. Radiation therapy is used only for inoperable forms. Since the tumor most often does not regress completely after irradiation, radiation therapy is generally considered as palliative. From 1979 to 1988, 18 patients with this rare tumor were referred to the Necker Hospital Tumor Center for radiation therapy. These patients have now been followed for 2 to 11 years. Tumors were extensive (Fish Stage C and D) in 75% of the patients and half of these patients showed cranial nerve involvement in addition to the usual otovestibular anomalies. Three patients were referred for recurrent tumors and 7 patients had undergone surgery just prior to radiation therapy. Among the 11 patients treated with the tumor in place, 7 had more or less complete regression of symptoms and radiologic signs, 3 had no further progression of symptoms and radiologic signs and 1 had tumor progression and expired as the result of the disease. No patient receiving post-operative radiation therapy developed clinical or radiological evidence of recurrent tumor. Among the 18 patients treated, 2 died of intercurrent disease. Our experience shows that a dose of 45 Gy is suffisant, leaves no trace, and does not prevent subsequent surgery. In an extensive review of the literature, tumor growth stopped or regressed after radiation therapy in 90% of the patients reported. Therefore, if incomplete surgery or neurological operative sequelae seem unavoidable, we prefer radiation therapy to surgical management of this tumor.

Adult↗
PubMed1990

[Amyloidosis disclosed by ORL manifestations].

Amylosis is characterized by an infiltration of acellular substance into the tissues. This substance is mainly made of protein molecules. This disease is primary or secondary to general disorders. Its anatomical polymorphism can well involve the ENT system. Its clinical pictures are well known by the ENT specialist. About tow amyloid tumors diagnosed because of oropharyngeous signs, the authors remind the main symptoms at the upper airway and ENT tracts; the local, regional and general treatment will be discussed.

Aged↗
PubMed1990

[Post-traumatic decompression of the optic nerve. Ophthalmologic and x-ray computed tomographic evaluation. Results in a series of 23 cases].

Post traumatic optic nerve compression gives a Clinic picture of physiological section. CT Scan is consistent with optic canal lesion when considering direct signs (bony fragments compressing the nerve) or indirect (fractures and hematoma of posterior orbital wall, of posterior ethmoid, and sphenoid). 23 patients had a surgical decompression through transethmoidosphenoidal approach. A lesion of optic canal was found in 22 out of 23 cases. Improvement of vision was noted in 12 cases.

Adolescent↗
PubMed1990

[Frontal and ethmoidal mucoceles. Apropos of 17 cases].

We have been studying 17 cases for operated mucoceles over a period of 4 years. Usual predisposing factors are often present, however we found no underlying malignant tumor revealed by a mucocele. Surgical treatment always included exclusion and filling with bone grafts in case of frontal involvement. Small ethmoidal lesions without symptom found on the CT scan are worrying because of their potential deterioration; in such cases, our attitude has been surgical.

Adolescent↗
PubMed1990

[Sinusitis during intensive care. Prospective studies].

Two series of ICU patients, the first one with nasal endotracheal intubation, the other one with a tracheostomy, were included in a prospective and comparative study with repeated CT scans of the sinuses. Radiological sinus involvement is seen in both groups almost constantly; purulent sinusitis are often seen in both series. Unexplained fever should make us look for a sinusitis, even in patients with early tracheostomy. Moreover, our results ask for more study about associated causes, apart from nasal endotracheal intubation.

Critical Care↗
PubMed1990

[Endocranial complications of chronic otitis in adults].

47 patients with intracranial abscess were admitted in the neurosurgical department of Professor Fohanno Pitié-Salpêtrière Hospital, between 1973 and 1989. Most often central abscesses were found. In 9 cases, the ear was the primary septic focus: 3 chronic otitis with cholesteatoma, 6 chronic otitis without cholesteatoma. In most cases, treatment included: Immediate drainage, Delayed surgery for the primary focus.

Adult↗
PubMed1989

[Decompression of the optic nerve through the trans-ethmoid-sphenoidal approach in orbital injuries. Technic and results apropos of a new series].

An orbital injury can be responsible for compressing the optic nerve in the optic canal. This compression leads to a syndrome of physiological division with homo-lateral blindness and absence of pupillary reaction of light during stimulation of the injured eye, whereas the light reflex is present with contralateral stimulation. Computed tomography studies show the compression site directly: optic canal fracture, or indirectly: hematoma of posterior ethmoidal cells and sphenoidal sinus, fracture of the posterior part of the orbit. This type of injury can be improved by surgical decompression of the optic nerve via a trans-ethmoid-sphenoidal approach. The surgical technique will be first described. Then, the authors will report a series of 13 cases. In 6 cases, surgical decompression allowed recovery of visual acuity. The authors emphasize the uncomplicated post-operative course. Indeed, no complication was recorded and the hospitalization time was very short.

Adolescent↗
PubMed1989

[Anatomic considerations on the pyramid and nasal septum. Quantitative data apropos of 33 dissections on fresh corpses].

The authors have dissected a series of nasal pyramids and septum. The various a anatomical structures have been measured and their relations with surgical landmarks have been recorded. Histograms show their findings. Surgical interest was emphasized for each stage of dissection. Some important points have been noticed during this study. They could bring some explanations to certain failures encountered after a septorhinoplasty.

Adult↗
PubMed1988

[A controversial procedure: rhinoplasty in children].

Confronted with nose malformations in children, surgeons experience at the same time a legitimate desire to rapidly attend to the altered anatomical structures, and a fear to aggravate the lesions existing initially by operating during a period of growth. Numerous animal experiments have not been conclusive as far as these two contradictory theses are concerned. In all cases, prudence remains mandatory, that is prudence towards the operational indications (important functional impairment), the date of the intervention (risk minimization with age), assessment of expected results (secondary malformations occurring even very late postoperatively).

Adolescent↗