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Biomedical subjects

D Chauvaud

Publications and source records attributed to D Chauvaud.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Simple retinal detachment: computer reconstruction of visual perception during the first month after surgery].

Visual function during the first month following ab externo surgery for retinal detachment with raised macula has been inadequately investigated. We present through pictures the patient's perception of his visual function after surgical intervention consisting of cryotherapy, draining, scleral buckling, and gas. The patient used image processing software to modify the pictures seen by the nonoperated eye in order to reproduce his visual perception with the operated eye. Results show the relation between visual perception and clinical examination. When the surgical procedure is undergone early, visual recovery only requires a few days and color vision returns quickly. Hyalitis and gas perception prevails at first, then visual acuity increases progressively and efficiently.

Color Perception↗
PubMed1999

e-PTFE as scleral buckling episcleral implants: an experimental and histopathologic study.

To investigate the effects of focal implantation of expanded polytetrafluoroethylene (e-PTFE) episcleral implants (i.e., explants or exoplants) on surrounding ocular tissues, an experimental and histopathological study was performed. Twenty-seven Fauve de Bourgogne rabbits eyes were implanted for a period of 3-11 months with oval-shaped e-PTFE episcleral implants. A newly formed capsule constantly encased the implants. Affected by the only two severe complications observed, 2 eyes had an endocapsular acute inflammation and could not be included in the study. Finally, 25 eyes were studied histopathologically. Neither intrusion nor extrusion of episcleral implants was observed. Other changes were related to implant characteristics. The inner surface of the capsule was often covered with numerous giant cells attesting to a foreign-body granuloma developed against the irregular outline of the episcleral implants. The porosity of the material was closely related to its surface irregularity, and also allowed its colonization by a fibrovascular and inflammatory tissue mainly in its peripheral layers. Under episcleral implants, sclera was both thinned and invaginated. Expanded PTFE hydrophobia was the other factor that might have suscitated granuloma. These microscopic changes are in contrast with an overall good apparent experimental tolerance to the material. However, additional studies on the long term behavior of this material would be helpful.

Animals↗
PubMed1999

Scleral and episcleral histological changes related to encircling explants in 20 eyes.

PURPOSE: To investigate scleral and episcleral histological alterations induced by encircling explants used in scleral buckling procedures. METHODS: We performed a histopathological study of 20 enucleated eyes after failure of retinal detachment surgery including encircling scleral buckle. RESULTS: Nonabsorbable materials were encapsulated and often gave rise to a limited scleral invagination. The inner capsular surface was regular in 10 silicone explants, it was partially covered with hydrogel fragments and a granulomatous foreign body giant cell reaction in 8 hydrogel explants. One Arruga thread was encased in fibrosis and a catgut circle showed no encapsulation. Other changes were mostly related to the long-standing retinal detachment: peripheral anterior synechiae, anterior uveal effusion, persistent retinal detachment, retinal gliosis, retinal atrophy, retinal breaks, and silicone oil droplets. CONCLUSION: All nonabsorbable explants underwent encapsulation and prompted scleral invagination. A granulomatous reaction accompanied hydrogel fragmentation. The long term fragmentation impact on implanted eyes remains unknown.

Adult↗
PubMed1999

Experimental encircling scleral buckle with silicone and hydrogel: histopathologic and comparative study of 26 rabbit eyes.

PURPOSE: To analyze histologic changes induced by encircling elements, rabbit eyes were implanted with two different biomaterials. MATERIALS AND METHODS: Thirty-seven rabbit eyes (37 rabbits) were implanted with encircling oval episcleral elements. Two materials were used: silicone sponge and hydrogel. The animals were killed and their eyes collected for histopathology. Of 37 eyes, 26 that were implanted for 111 to 455 days were selected for the study. RESULTS: In 26 eyes, scleral buckling was visible. Scleral examination showed a regular erosion under the buckle, mainly with silicone. All explants were surrounded by a fibrous capsule, which was smooth and regular with silicone. With hydrogel, fragmentation was observed with a giant cell reaction. Capsule thickness increased, mainly with hydrogel. CONCLUSION: Fragmentation affected segmental or circumferential hydrogel explants. As in silicone explants, the capsule surface was normal when the hydrogel surface was respected. The fragmentation mechanism remains unclear.

Animals↗
PubMed1999

[Long-term comparative anatomic results of retinal detachment with vitreoretinal proliferation operated with or without using liquid perfluorocarbons].

PURPOSE: To investigate whether peroperative perfluorocarbon liquids (PFCL) improve the long term anatomical success of retinal detachment associated with severe proliferative vitreoretinopathy (PVR). PATIENTS AND METHODS: The charts of 62 successive patients operated on for retinal detachment associated with severe PVR were retrospectively analyzed. For one group of 39 patients PFCL were used intraoperatively to improve membrane dissection. The anatomical status of the two groups were compared one month after surgery and at least 6 months after silicone oil ablation. RESULTS: Anatomical success was observed in 84.6% in the group of patients operated with PFCL compared to 52% in the other group (P = 0.005). At the end of the follow up, anatomical success was observed in 64% of patients operated with PFCL compared to 61% in the control group (P = 0.8). However, recurrences were observed later in the group operated on with PFCL. CONCLUSION: Perfluorocarbons liquids significantly improve the initial reattachment of retinal detachment complicated with severe PVR, but they do not seem to improve their final anatomical status.

Adult↗
PubMed1999

[Histological changes related to scleral buckling for treatment of retinal detachment].

Treatment of retinal detachment frequently uses biocompatible materials to obtain scleral buckling. These materials are not devoid of consequences on surrounding tissues. In 3 eyes enucleated for failure of surgical treatment using scleral buckling materials, the changes prompted by episcleral implants could be observed. The sclera underwent both an inversion of its curvature and a reduction of its thickness under the material, as well as an encapsulation of the material was observed. While a silicone sponge was used in part to encircle one of these eyes, its capsular inner surface was regular and smooth. In contrast, hydrogel implants used in the three eyes showed a peripheral fragmentation prompting in two of them a typical foreign body giant cell granulomatous reaction. Changes in scleral curvature and scleral thinning were observed reflecting the consequences of the buckling procedure. The capsule formation occurred as it does for any nonabsorbable matérial implanted in tissues. Degradation and fragmentation of the hydrogel material suscitated a granuloma in response to fragments. These hydrogel specific changes should be recognized on microscopic examination of slides of either capsule or eyes previously in contact with this implanted material. They attested of the instability of hydrogel after implantation.

Aged↗
PubMed1998

Encapsulation of scleral buckling materials. A study of sixty specimens.

OBJECTIVE: The purpose of the study was to obtain information on the encapsulation of two nonabsorbable biomaterials (silicone and hydrogel) used as explants in scleral buckling in retinal detachment surgery. DESIGN: The study design was a histopathologic study on a cohort of capsule fractions and complete eyes. PARTICIPANTS: Fifty-nine patients participated in this study, in which 60 specimens, including 37 hydrogel and 21 silicone capsule specimens as well as 2 whole eyes, were gathered. There were no control subjects. INTERVENTION: The capsule specimens were obtained from eyes operated on previously for scleral buckling for retinal detachment. The two whole eyes were enucleated. All specimens were studied with routine optic microscopy. MAIN OUTCOME MEASURES: Patient characteristics, type of scleral buckling, and number of operations performed were analyzed. Histologically, the capsular structure, its interface with the explant, and its different components also were studied. Remnants of the buckling material also were investigated. RESULTS: There were 45 male and 14 female patients, with a mean age of 49 years. Histologically, capsule specimens had a fibrous matrix with fibroblasts and few inflammatory cells. Eighteen (48.6%) of 37 hydrogel capsule specimens displayed hydrogel fragments surrounded by a foreign body giant cell granuloma in 16 cases. CONCLUSION: Nonabsorbable materials undergo encapsulation after implantation on the eye surface. Giant cell granuloma was observed in some hydrogel capsule specimens in relation to hydrogel fragmentation. The exact origin of this fragmentation remains unknown.

Adolescent↗
PubMed1998

Silicone oil removal combined with macular pucker dissection: a retrospective review of 14 cases.

PURPOSE: Silicone oil must be removed from the eye to avoid late complications after the surgical management of proliferative vitreoretinopathy (PVR). Macular pucker, frequently observed after retinal detachment surgery, is responsible for visual impairment. The safety of a procedure combining epimacular membrane peeling and silicone oil removal was retrospectively evaluated. METHODS: Fourteen eyes that had previously undergone vitrectomy and silicone oil tamponade for rhegmatogenous retinal detachment with severe PVR, penetrating or blunt trauma, and intraocular foreign bodies were included. Silicone oil tamponade was maintained for a mean period of 30 weeks (range, 12-108 weeks). The removal of silicone oil was combined with the peeling of an epimacular membrane. RESULTS: Mean follow-up after silicone oil removal was 86 weeks (range, 13-234 weeks). The final retinal reattachment rate was 78%. Macular pucker recurred in one eye after a 24-month period. Best-corrected visual acuity improved two lines or more in eight eyes (57%) and reached 20/200 or better in eight eyes (57%) at last follow-up. CONCLUSION: Macular pucker dissection and silicone oil removal can be safely combined. This single procedure can obviate the need for further surgery in eyes that have already undergone multiple operations and allows good visual recovery.

Adolescent↗
PubMed1997

Choroidal neovascularization complicating epiretinal membrane removal.

PURPOSE: Surgical removal of epiretinal membranes generally leads to anatomic and functional improvement. Main complications include cataract, retinal breaks and detachment. We describe the onset of a juxtafoveal choroidal neovascularization 2 years after surgery of an epiretinal membrane. METHODS: The neovascular membrane was treated by argon laser photocoagulation. RESULTS: Complete obliteration of the neovascularization was obtained resulting in functional improvement. CONCLUSIONS: Although rare, choroidal neovascularization as a complication of epiretinal membrane surgery must be suspected in case of poor visual outcome or relapse of symptoms.

Adult↗
PubMed1997

[Posterior scleral reinforcement surgery].

UNLABELLED: Scleral reinforcement is proposed to stabilize the visual acuity in patients with macular myopic staphyloma. Although many patients have been treated, this procedure is still debated. PURPOSE: Evaluation of the feasibility of scleral reinforcement and the operative risk of this procedure. PATIENTS AND METHODS: Patients were eligible for this prospective study patients with a clinical history of visual loss, staphyloma concerning the macular area associated with atrophic lesion and or lacquer cracks. Sixteen eyes in 13 successive patients have been operated on with a single band of PTFE. RESULTS: At the last examination, visual acuity was unchanged for 14 cases. In one case, an improvement of the vision was related to the disappearing of a macular detachment by shortening of the axial length. In one case, vision decline was associated with inadequate band position. Diplopia occurred in 2 cases. A choroidal detachment, and a vitreous haemorrhage disappeared without sequelae. CONCLUSION: An accurate technique is necessary to avoid operative risk. Further long term studies are needed to assess the benefit of scleral reinforcement.

Adult↗
PubMed1997

[Rigid endoscope with Gradient-index lenses. Preliminary studies].

PURPOSE: Endoscopes for use in ophthalmology can be manufactured in dimensions smaller than 0.89 mm. MATERIALS: Gradient-index lenses that give a higher resolution than fiber bundles can be miniaturized down to 0.35 mm. RESULTS: We used this new endoscope in 6 eyes of 6 patients during anterior segment surgery. Preliminary clinical experience has demonstrated the usefulness and practical application of this new instrument. CONCLUSION: The clear views the instrument provides of the ciliary sulcus and ciliary body behind the iris make it useful in secondary posterior chamber intraocular lens implantation, retroprosthetic membrane behind keratoprosthesis, Molteno valve, and in endolaser photocoagulation.

Aged↗
PubMed1996

[Rhegmatogenous retinal detachment].

Among all the types of retinal detachments, the most common are rhegmatogenous detachments, as defined by the presence of a break in the retina. This is the predominant factor in their mechanism. For this reason, treatment is exclusively surgical and consists of sealing the retinal holes by adhesion. The main cause is modification of the vitreous fluid due to age. Presently, surgery obtains good functional results if undertaken rapidly: retinal detachment is an emergency. An essential factor in prophylaxy is information of patients and physicians.

Humans↗