Biomedical subjects

B F Engels

Publications and source records attributed to B F Engels.

5 recordsLinked to original sources

PubMed2003

UBM-guided chamber angle surgery for glaucoma management: an experimental study.

PURPOSE: The aim of this experimental study was to investigate the potential of ultrasound bimicroscopy (UBM)-guided chamber angle surgery as an alternative or supplement to gonioscopy and intraocular microendoscopy for intraoperative control. METHODS: In 15 porcine cadaver eyes, mechanical goniopuncture or punctual Er:YAG laser trabecular ablation was performed without operating microscope or gonioscopy, but with real-life ultrasound biomicroscopy monitoring with a 50 MHz transducer. Intraoperative localization of the microsurgical instruments and tissue-instrument contact were qualitatively evaluated. RESULTS: The instruments could be clearly visualized within the chamber angle and disturbing artefacts were only minimal when using mechanically fixed instruments in slow motion. Topographic localization, tissue contact, and penetration depth of the instruments entering the scleral were well illustrated as far as the technical resolution limits of UBM would allow. CONCLUSIONS: UBM can be used intraoperatively to monitor the correct manoeuvring of microsurgical instruments in selected ab interno procedures. Some adaptations and further modifications of the technique presented here will be necessary before UBM-guided surgery can be considered for clinical use in humans.

Animals↗

PubMed2002

Ultrasound biomicroscopy and its value in predicting the long term outcome of viscocanalostomy.

AIMS: To examine whether the early postoperative morphology at the site of sclerectomy, as visualised by ultrasound biomicroscopy (UBM), is an indicator of the mechanisms that lower intraocular pressure (IOP) and/or predictors of the long term outcome of viscocanalostomy. METHODS: 15 eyes of 14 patients with medically uncontrolled open angle glaucoma and no history of surgery underwent viscocanalostomy according to Stegmann's technique. Ultrasound biomicroscopy was performed during the first month after surgery. The following parameters were assessed: dimensions of the intrascleral "lake," presence of a filtering bleb, presence of a subconjunctival cavity or a suprachoroidal hypoechoic area, and the thickness of the residual trabeculocorneal membrane. A complete ophthalmological examination was performed the day before and the day after surgery. Follow up visits were scheduled 1 week, 4 weeks, 6 months, and 12 months after surgery. RESULTS: At 1 year successful control of IOP (<20 mm Hg) was achieved without further manipulation or medication in six of 15 eyes. The size of the intrascleral "lake" (average 0.62 mm(3)) did not correlate with later IOP; however, a visible route under the scleral flap and accidental perforation of the trabeculocorneal membrane were associated with long term lowering of IOP. Normal thickness of the trabeculocorneal membrane (0.10-0.15 mm) was indicative of IOP control with and without medication. When UBM showed an early collapse of the intrascleral cavity, control of IOP was not achieved. Other UBM findings did not predict long term function. CONCLUSION: In accordance with previous studies, the authors found that UBM examination is a useful method to evaluate outflow mechanisms after glaucoma surgery. This study shows that UBM imaging of external filtration during the early postoperative period can be used to predict the success of viscocanalostomy. However, to establish conclusively what parameters of UBM predict successful viscocanalostomy a larger number of patients must be studied.

Adult↗

PubMed2001

The suitability of the ultrasound biomicroscope for establishing texture in giant cell arteritis.

AIM: To establish whether ultrasound biomicroscope (UBM) is a helpful tool in locating the arterial segment responsible in patients with segmental attacks in giant cell arteritis METHODS: The superficial temporal arteries of 19 patients with suspected giant cell arteritis were examined with the UBM before biopsy. RESULTS: 20 specimens provided the histological proof of giant cell arteritis in five patients. Side differences, a dark perivascular halo, and high reflexivity of the intra-arterial space were found. CONCLUSION: it is assumed that there are two types of arteritic inflammation: (1) the occlusion of intra-arterial space due to intimal fibrosis (UBM: high reflexive "filling"), and (2) inflammation of the perivascular zone with oedematous thickening and infiltration of the media (UBM: dark halo) and its combination. UBM is helpful in obtaining an indication of the side and segment for biopsy.

Aged↗

PubMed2000

Ultrasound biomicroscopic patterns after glaucoma surgery in congenital glaucoma.

OBJECTIVE: This study aimed to demonstrate specific morphologic patterns in congenital glaucoma after various surgical procedures by means of ultrasound biomicroscopy (UBM) and to investigate correlations between UBM morphology and the effectiveness of glaucoma surgery in reducing intraocular pressure. DESIGN: Observational case series. PARTICIPANTS AND INTERVENTIONS: Thirty four eyes of 18 consecutive patients, not older than 18 years, with congenital glaucoma and with a history of previous antiglaucomatous surgery underwent UBM examination of the anterior chamber angle in the treatment area and in an untreated region. MAIN OUTCOME MEASURES: The morphology of the anterior chamber angle region and the tissue reflectivity were analyzed. RESULTS: Specific UBM patterns of the anterior chamber angle in congenital glaucoma were observed after goniotomy, trabeculotomy, trabeculectomy, deep sclerectomy, and cyclodialysis. In the first months after surgery, a limited correlation was found between morphology and the success of filtering surgery. Adhesions of the iris or the ciliary processes to the trabeculectomy cleft were detected in 19 of 25 eyes after filtering procedures. CONCLUSIONS: In cases of cloudy cornea and unknown previous glaucoma surgery, UBM can be used to identify the type and localization of previous surgery in congenital glaucoma, thus assisting surgical planning for subsequent glaucoma management. The correlation between UBM morphology and the effectiveness of filtering surgery is less convincing than previously demonstrated in adults, possibly underlining the importance of individual nonsurgical factors for prognosis in congenital glaucoma.

Adolescent↗

PubMed1999

[Ultrasound biomicroscopy diagnosis of congenital glaucoma].

BACKGROUND: In children with congenital glaucoma the assessment of the anterior chamber and the chamber angle might be difficult since scarring and opacities of the cornea are often seen. The purpose of our study was to reveal in vivo--morphology of the anterior segment in patients with congenital glaucoma and opaque cornea. PATIENTS AND METHODS: In 46 eyes of 23 children with different degrees of corneal opacities we performed ultrasoundbiomicroscopy (UBM) of the anterior chamber after having performed a complete ophthalmological examination in general anesthesia. RESULTS: Massive abnormalities of the anterior segment morphology were detected in 5 eyes with completely cloudy cornea. In eyes with partial opacity of the cornea, UBM gave additional information concerning the anterior chamber angle topography, as iris remnants in aniridia, or anterior synechia. CONCLUSION: Especially in cases with extensive corneal opacities the UBM allows us to get morphological and topographic information about the anterior segment and helps to establish an individual strategy for surgical management.

Anterior Eye Segment↗