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Biomedical subjects

Peter Stalmans

Publications and source records attributed to Peter Stalmans.

11 recordsLinked to original sources
PubMed2007

Sub-inner limiting membrane haemorrhage: causes and treatment with vitrectomy.

BACKGROUND: Preretinal haemorrhages usually occur at the interface between the posterior hyaloid and inner limiting membrane (ILM). Less frequently, they are located between the ILM and the retinal nerve fibre layer. Sub-ILM haemorrhages have been described in a variety of clinical settings and often lead to severe visual impairment because of their predilection for the macular region. METHODS: A consecutive series of five cases in which sub-ILM haemorrhages were clinically suspected and confirmed during early vitrectomy with ILM peeling were reviewed. RESULTS: Sub-ILM haemorrhages were clinically suspected in five patients (median age 32 years) based on the fundoscopic appearance and clinical setting of Terson's syndrome (n = 1), Valsalva retinopathy (n = 2), blood dyscrasia (n = 1) and blunt facial trauma (n = 1). Vision was severely impaired in all patients (to hand movements in four of five) because of a premacular location of the haemorrhage. All patients were treated with early pars plana vitrectomy because of insufficient spontaneous visual recovery after a median of 6 weeks. The sub-ILM location of the haemorrhage could be confirmed intraoperatively in all patients by biostaining of the membrane overlying the haemorrhage. ILM peeling and aspiration of the haemorrhage resulted in excellent visual recovery in all patients. No procedure-related complications were observed. CONCLUSIONS: Sub-ILM haemorrhages often occur in a specific clinical context and can lead to severe visual impairment in young patients. Given the excellent results and low complication rates, timely surgical intervention is justified when spontaneous resorption is insufficient.

Adult↗
PubMed2006

Expression of VEGF and PEDF in choroidal neovascular membranes following verteporfin photodynamic therapy.

PURPOSE: To examine the impact of photodynamic therapy (PDT) on pigment epithelium derived factor (PEDF) expression in human choroidal neovascularization (CNV) membranes with regard to vascular endothelial growth factor (VEGF) expression. DESIGN: Interventional case series. METHODS: Retrospective review of interventional case series of 42 patients (42 eyes) who underwent removal of CNV. CNV was secondary to age-related macular degeneration (AMD) in all cases. Fifteen patients were treated with PDT, 3 to 246 days before surgery. CNV were stained for CD34, CD105, cytokeratin 18, VEGF, and PEDF. Twenty-seven CNV without previous treatment were used as control. RESULTS: Specimens without pretreatment disclosed varying degrees of vascularization, VEGF, and PEDF expression by different cells. Specimens treated by PDT, three days previously showed mostly occluded vessels lined with damaged endothelial cells (EC). In contrast, specimens excised at later time points after PDT were highly vascularized with healthy EC. This chronology was associated with an impressive VEGF immunoreactivity increased considerably in retinal pigment epithelial cells as well as significantly reduced PEDF expression in EC and stroma. CONCLUSIONS: PDT induces a selective vascular damage in CNV. The effectiveness of PDT, however, seems to be jeopardized by a rebound effect initiated by an enhanced VEGF and reduced PEDF expression in CNV.

Aged↗
PubMed2006

Systemic absorption of 5-fluorouracil during vitrectomy.

PURPOSE: The aim of this study is to determine if systemic absorption is present after 5-fluorouracil (5FU) is used in the vitrectomy infusion. DESIGN: A two-case clinical study. METHODS: A catabolite of 5FU, alpha-fluoro-beta-alanine (FBAL), was measured in urine samples of two patients who underwent vitrectomy using 5FU in the infusion fluid. RESULTS: In both patients, FBAL was found in the urine samples collected up to 48 hours after the surgery, although in significantly different concentrations. CONCLUSIONS: The use of 5FU in the vitrectomy infusion fluid to prevent the formation of proliferative vitreoretinopathy may lead to significant general absorption and may be avoided in children and young adults.

Absorption↗
PubMed2006

Optical coherence tomographic documentation of the formation of a traumatic macular hole.

PURPOSE: To assess how optical coherent tomography 3 (OCT3) images help explain the mechanism of traumatic macular hole formation. DESIGN: Observational case report. METHOD: A patient presented with an altered foveal depression after a unilateral blunt eye trauma. After four days, the injury developed into an impending macular hole. Follow-up was done by ophthalmic examination, fundus photography, and OCT3. RESULTS: Fundus examination showed a macular edema at first presentation, with a dot hemorrhage next to the fovea and a perifoveal little yellow ring. Minimal macular edema and a small foveal depression were seen on OCT3. After four days, an impending hole had formed. The foveal cyst closed after one month, but subretinal fluid persisted for months. After six months, full recovery was observed. CONCLUSIONS: Subclinical foveal changes occurred directly after the trauma, preceding macular hole formation. OCT3 allows detection of small lesions, which helps explain the pathogenesis of traumatic macular hole formation.

Adult↗
PubMed2006

Results of compensatory extraocular muscle surgery after macular translocation.

PURPOSE: Macular translocation is an optional surgical treatment for age-related macular degeneration. However, this technique induces postoperative torsional complaints and surgical counterrotation of the globe is mandatory. The purpose of this study is to report the effect of compensatory extraocular muscle surgery upon the torsional complaints in patients who underwent a macular translocation procedure. DESIGN: The pre- and postoperative data on the first 35 patients in our department who underwent a counterrotation procedure after macular translocation surgery are reviewed. METHODS: From November 2001 to January 2005, 35 patients underwent a macular translocation procedure, with subsequent extraocular muscle surgery to counterrotate the eye. Three types of rectus muscle transposition procedures were used: full-tendon transposition of two opposite rectus muscles, "crossed" half-tendon transposition of all rectus muscles ('split & cross' procedure), and "uncrossed" half-tendon transposition of all rectus muscles ('split & neighbor cross' procedure). In the majority of patients these procedures were associated with oblique muscle surgery. RESULTS: With the selected procedures, retinal excyclodeviations are easier to correct then retinal incyclodeviations. In our hands, full-tendon transposition of two opposite rectus muscles with or without associated oblique muscle surgery, never corrects more than 30 degrees. 'Split & cross' procedures combined with oblique muscle surgery are sufficient for retinal excyclodeviations of 30-45 degrees and for incyclodeviations of up to 30 degrees; 'split & neighbor cross' procedures combined with oblique muscle surgery are sufficient for retinal excyclodeviations of 45-65 degrees and for incyclodeviations of up to 40 degrees . CONCLUSIONS: The effect of the various procedures appears to be predictable. It is possible to select a surgical procedure as a function of the amount of retinal cyclodeviation.

Adult↗
PubMed2003

Trypan blue not toxic for retinal pigment epithelium in vitro.

PURPOSE: To investigate whether trypan blue has a toxic effect on cultured retinal pigment epithelial (retinal pigment epithelium) cells. DESIGN: Experimental study with a direct live/dead cell staining technique using fluorescent dyes. METHODS: Cultured human retinal pigment epithelium cells were exposed for 5 minutes to various concentrations of trypan blue (0.06%, 0.15%, 0.30%), and cell viability was confocally measured. RESULTS: No increased cell death was found in cultures incubated in any of the trypan blue concentrations used. CONCLUSION: These findings indicate that a short exposure of trypan blue does not have a toxic effect on cultured retinal pigment epithelium cells.

Cell Survival↗
PubMed2003

Anatomical and visual outcome of macular hole surgery with infracyanine green-assisted peeling of the internal limiting membrane, endodrainage, and silicone oil tamponade.

PURPOSE: To evaluate the anatomical and visual outcome in macular hole patients who underwent surgery with infracyanine green-assisted internal limiting membrane peeling. DESIGN: A prospective case series with 51 consecutive eyes of 49 patients with idiopathic, iatrogenic, or traumatic Stage 2, 3, or 4 macular holes. METHODS: After removing the vitreous, in all eyes infracyanine green-assisted removal of the internal limiting membrane was performed. Patients older than 65 years of age underwent a simultaneous phacoemulsification. At the end of surgery, a silicone oil tamponade was used in all cases, and all patients were asked to position face down for 24 hours. Optical coherence tomography was performed preoperatively and postoperatively to determine the macular hole stage/size and the anatomical closure rate, respectively. RESULTS: The mean follow-up time was 9.8 months (range, 6-26 months). The overall median duration between the first symptoms and the surgery was 5 months. The overall anatomical success rate after one surgery was 92% (47 eyes), while that of chronic and nonchronic ones was 72.3% and 97.5%, respectively. The median preoperative visual acuity was 20/160 (range, 20/30 to counting fingers) and increased to 20/50 (range, 20/20 to 20/400) postoperatively. The mean increase in visual acuity was 3.7 lines (range, -4 to 10 lines). Of all 51 operated-on eyes, 26 (51%) eyes had a final visual acuity of 20/50 or better. CONCLUSIONS: These findings indicate that infracyanine green-assisted removal of the retinal internal limiting membrane appears to induce a high incidence of anatomical closure, with good visual outcome.

Adult↗
PubMed2003

Trypan blue staining in vitreoretinal surgery.

PURPOSE: To evaluate the efficacy of trypan blue for staining the internal limiting membrane (ILM) and epiretinal membranes (ERM) in vitreoretinal surgery. DESIGN: Prospective noncomparative case series. PARTICIPANTS: Fifty eyes of 50 patients with macular pucker (n = 22), macular hole (n = 18), or a combination (n = 2), proliferative vitreoretinopathy (n = 5), or diabetic retinopathy (n = 3). METHODS: Trypan blue 0.2% was used to stain the ILM or ERM during vitreoretinal surgery. MAIN OUTCOME MEASURES: The intraoperative visibility of the membranes was scored as poor, moderate, good, or excellent. RESULTS: The application of trypan blue onto the ILM or the ERM resulted in a useful bluish staining, facilitating the identification, delineation, and removal of the membranes in all surgeries. No residual staining or adverse effects related to the dye were observed. CONCLUSIONS: Trypan blue stains both ILM and ERM and might be an useful tool in vitreoretinal surgery.

Adult↗
PubMed2002

Trypan blue staining of epiretinal membranes in proliferative vitreoretinopathy.

OBJECTIVE: To determine whether trypan blue staining facilitates epiretinal membrane (ERM) removal in proliferative vitreoretinopathy. METHODS: In 10 patients undergoing vitrectomy for proliferative vitreoretinopathy, ERM peeling was performed without staining the tissue, until no additional ERMs were clearly visible. Then, after a fluid-air exchange, 0.06% trypan blue solution was applied onto the retinal surface. After 1 minute, all excess dye was removed and, after an air-fluid exchange, ERM peeling was completed. Excised ERM specimens were analyzed by transmission electron microscopy. MAIN OUTCOME MEASURES: For each patient, the efficacy of trypan blue staining of ERMs during surgery was scored. RESULTS: In all patients, intraoperative staining of ERMs with trypan blue was found to be a useful adjunct, since the dye consistently improved direct visualization and delineation of ERMs and facilitated ERM removal. A clear contrast was created between the stained ERMs and the nonstaining, underlying retina. Electron microscopy showed that only ERM tissue was removed. No adverse reactions related to the use of the dye were observed up to 3 months after surgery. CONCLUSIONS: Trypan blue may be an important new tool in the surgical management of proliferative vitreoretinopathy, since it may allow a more complete and safer ERM removal.

Aged↗
PubMed2002

Toxic effect of indocyanine green on retinal pigment epithelium related to osmotic effects of the solvent.

PURPOSE: To investigate whether the toxic effect on cultured retinal pigment epithelial (RPE) cells after application of indocyanine green is related to the osmolarity of the solvent or to toxic effects of the dye and evaluate whether these changes also occur using infracyanine green. DESIGN: Experimental study with a direct live/dead cell staining technique using fluorescent dyes. METHODS: Cultured human RPE cells were exposed to various solutions and cell viability was confocally measured. RESULTS: Increased cell death was found in cultures incubated in the hypoosmotic solvent that is generally used for indocyanine green (P <.001, n = 12). Addition of indocyanine green did not alter this observation (P <.001, n = 12). In cultures exposed to a 5% glucose solution, no increased cell death was found (P =.94, n = 12), nor when infracyanine green was added (P =.13, n = 12). CONCLUSION: The observed toxicity of indocyanine green on RPE cells is probably related to the hypo-osmolarity of the solvent and may be avoided by using infracyanine green dissolved in glucose 5%.

Cell Death↗