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At least 1,171 records · Page 65Linked to original sources
PubMed2006

A pilot study on slit lamp-adapted optical coherence tomography imaging of trabeculectomy filtering blebs.

BACKGROUND: Our study aims to identify anatomical characteristics of glaucoma filtering blebs by means of slit lamp-adapted optical coherence tomography (SL-OCT) and to identify new parameters for the functional prognosis of the filter in the early post-operative period. METHODS: Patients with primary open-angle glaucoma, aged 18 years and older, scheduled for primary trabeculectomy at the Department of Ophthalmology, Radboud University Nijmegen Medical Centre, were considered for our study. All patients underwent standardized trabeculectomy with intra-operative application of mitomycin C. The filtering blebs were evaluated clinically and with SL-OCT on day 1 and 1, 2, 4 and 12 weeks following surgery. The resulting data were analysed and weighed against surgical success. To better understand the SL-OCT data a small comparative histologic study was performed. RESULTS: The study included 20 eyes of 20 patients. After completion of our study, 15 eyes of 15 patients (mean age+/-SD 67 +/- 16 years) were eligible for data analysis and 5 eyes missed at least one follow-up visit. Filtering surgery was considered successful (intraocular pressure < or = 21 mmHg without antiglaucomatous medication) in 11 of 15 eyes. SL-OCT frequently demonstrated multiple hypo-reflective layers within Tenon's capsule ("striping" phenomenon) in the first post-operative week. Presumably, these layers corresponded with drainage channels in the histological specimen. These channels were present in functional filters but not in the failures. In addition, the visualisation of the sclera below the filtering zone was better defined in failures compared with successful filtering blebs ("shading" phenomenon). We observed no differences in the volume and clinical aspect of the blebs in the successful group compared with the unsuccessful group. CONCLUSIONS: Successful filtering blebs show characteristic optical properties on SL-OCT. These phenomena suggest a diffusely enhanced fluid content and the presence of intra-bleb drainage channels in functional filtering blebs.

Aged↗
PubMed2002

[Drainage systems in glaucoma surgery].

Glaucoma drainage devices, also known as aqueous shunts (AS) are widely used in the USA. They consist of a silicone tube that is inserted into the anterior chamber and connected to a plate made of silicone or polypropylene, the explant. The latter is positioned between the recti muscles and over several weeks the surrounding tissue forms a fibrous bleb around the plate. This serves as a permanent filtration reservoir.Recurrent failure of filtrating surgery is the main indication for the use of AS. Other indications include situations in which the formation of a filtering bleb seems to be unpromising because of extensive conjunctival scarring. Qualified success has been achieved for many years in 50-100% of the eyes treated depending on patient selection. The most serious complication is postoperative hypotonia that can lead to serious chorioidal detachment, suprachorioidal hemorrhage, flat anterior chamber and corneal decompensation. To avoid this complication some devices, i.e.the Ahmed Glaucoma and the Krupin valve have integrated mechanisms to sustain a residual intraocular pressure. With other devices i.e. the Molteno and the Baerveldt devices, the tube has to be temporarily ligated until bleb formation has started. On the other hand fibrous infiltration of the bleb 1-4 months after the surgery often leads to a reversible rise in introcular pressure, which can be treated by massaging the bulbus, needling the bleb or injection of antimetabolites. There are no obvious differences between the various forms of AS with regard to the success of pressure regulation. In summary,by close scrutiny of indications and management of complications,drainage systems are a useful option in the management of complicated glaucoma that carry a high risk of failure from conventional filtering surgery.

Equipment Design↗
PubMed1995

Perforation of the inferior vena cava by a recently inserted Greenfield filter.

The Greenfield filter is an effective device which provides protection against emboli to the lungs from the deep veins of the lower half of the body. Specific complications, such as perforation, may occur following the placement of caval filters. We report a case of inferior vena cava perforation by a Greenfield filter diagnosed at the time of surgery. With the increasing use of caval filter placement, specific complications such as this will be encountered.

Female↗
PubMed2000

Development of a completely closed circuit using an air filter in a drainage circuit for minimally invasive cardiac surgery.

The completely closed circuit system is the future direction of cardiopulmonary bypass because of its compactness and superior biocompatibility. The most serious obstacle for clinical application is the sucking of air bubbles into the drainage circuit. The purpose of this study was to remove the air bubbles from the drainage circuit. Infusing 50 ml/min of air bubbles into the drainage circuit of the usual closed circuit, and infusing 50, 100, and 150 ml/min of air into the drainage circuit of a newly developed closed circuit (drainage circuit using an air filter), the number and size of air bubbles were observed at the outlet of the arterial filter. In the usual closed circuit, many air bubbles of over 40 microm were detected within 5 s at a blood flow of 4 L/min because the centrifugal pump decreased the size of the bubbles, which then passed through the oxygenator and arterial filter. Air bubbles of over 40 micro were not detected in the newly developed closed circuit within 5 min at a blood flow of 4 L/min. The removal of air mixed into the completely closed circuit was possible with a drainage circuit using an air filter that was developed. The clinical use of the completely closed circuit for minimally invasive cardiac surgery (MICS) became possible based on this development.

Air↗
PubMed1981

Changes in left ventricular wall motion after coronary artery bypass surgery: signal or noise?

We evaluated changes in ventricular wall motion after surgery by comparing smoothed, filtered measurements of regional percent shortening (RPS) from right anterior oblique ventriculograms in 37 patients before and after surgery. After surgery there was a significant (p less than 0.05) decrease in the number of regions with hypokinetic wall motion. The distribution of RPS values was also different (p less than 0.005). However, the mean value of RPS for the surgery group as a whole was not significantly altered. These data were contrasted with RPS data from 11 control patients, who were each studied twice but did not have surgical intervention. Similar analysis of the control group did not show any significant change between studies in the number of hypokinetic regions, and the distributions of RPS for the first and second angiograms were not different. We found a 10.3% absolute mean change in repeated measurements of RPS in the control group. We conclude that significant changes occurred after surgery that were not evident in the control group, and the amount of variability in repeated measurements of RPS suggests that analysis should be applied to group rather than individual data.

Coronary Artery Bypass↗
PubMedDate not supplied

The outcome of the functioning filter after subsequent cataract extraction.

OBJECTIVE: To evaluate and compare the outcome of functioning filtration surgery followed by cataract surgery with posterior intraocular lens implantation by both phacoemulsification and extracapsular cataract extraction (ECCE) techniques in glaucomatous eyes. PATIENTS AND METHODS: We retrospectively evaluated the clinical course of 77 eyes (68 patients) that after successful trabeculectomy, underwent cataract surgery by either phacoemulsification or ECCE techniques. We determined the frequency of partial and absolute failure following cataract surgery by either phacoemulsification or ECCE in eyes with functioning trabeculectomies. Partial failure of intraocular pressure (IOP), control after cataract extraction was defined as the need for an increased number of antiglaucoma medications or argon laser trabeculoplasty to maintain IOP < or =21mm Hg. Complete failure of IOP control after cataract surgery was defined as an IOP >21 mm Hg on at least two consecutive measurements one or more weeks apart or the performance of additional filtration surgery. Failure rates were calculated using the Kaplan-Meier actuarial method. Failure rates between phacoemulsification and ECCE subgroups were compared using the log rank test. RESULTS: The probability of partial failure by the third postoperative year after cataract surgery was 39.5% in the phacoemulsification subgroup and 37.3% in the ECCE subgroup. This small difference is not statistically significant (P = 0.48). The probability of complete failure by the fourth postoperative year after cataract surgery was 12.0% in the phacoemulsification subgroup and 12.5% in the ECCE subgroup. This difference is also not statistically significant (P = 0.77). At the 6-month follow-up visit, visual acuity of both groups improved one or more lines in 87.0% of patients, and worsened one or more lines in 3.9% of patients. Sixty-one percent achieved visual acuity of 20/40 or better. The most frequent complication was posterior capsular opacification requiring laser capsulotomy that occurred in 31.2% of patients. CONCLUSION: Cataract extraction by either phacoemulsification or ECCE following trabeculectomy surgery may be associated with a partial loss of the previously functioning filter and the need for more antiglaucoma medications to control IOP.

Aged↗
PubMed1989

Monochromatic endoillumination for epimacular membrane surgery.

We attempted to simultaneously increase visualization of epimacular membranes and minimize retinal phototoxicity by filtering the light of the endoilluminator during vitreous surgery. The monochromatic filters we employed to eliminate short wavelengths were not useful because they reduced the level of illumination. We advise using the lowest level of illumination possible and an ultraviolet/infrared filter over the light source when working close to the retinal surface. The filter can be adapted to replace the fluorescein filter in the Ocutome console to facilitate insertion and withdrawal.

Evaluation Studies as Topic↗
PubMed1991

Variability of somatosensory cortical evoked potentials during spinal surgery. Effects of anesthetic technique and high-pass digital filtering.

The effects of anesthetic technique (nitrous oxide or propofol) and high-pass digital filtering on within-patient variability of posterior tibial nerve somatosensory cortical evoked potentials (PTN-SCEP) were compared prospectively in two groups of 20 patients undergoing spinal surgery. Average P1N1 amplitude was significantly higher and P1N1 amplitude variability lower during propofol/alfentanil anesthesia than during nitrous oxide/alfentanil anesthesia. Off-line 30-Hz high-pass digital filtering significantly reduced P1N1 amplitude variability without decreasing P1N1 amplitude. In 93 patients studied retrospectively, a significant negative logarithmic correlation (r = -0.77) was observed between P1N1 amplitude and P1N1 amplitude variability. This study shows the importance of maintaining the highest possible PTN-SCEP amplitudes during spinal surgery. Propofol/opioid anesthesia may be an alternative anesthetic technique to nitrous oxide/opioid anesthesia during spinal cord function monitoring.

Adult↗
PubMed1998

Management of large, leaking, and inadvertent filtering blebs with the neodymium:YAG laser.

OBJECTIVE: The purpose of the study was to test the efficacy of the neodymium:YAG (Nd:YAG) laser for repairing filtering blebs. DESIGN: The study design was a prospective study. PARTICIPANTS: Five eyes of five patients with leaking blebs (group 1), five eyes of five patients with large irritating blebs (group 2), and four eyes of four patients with inadvertent filtering blebs in the surgical wound after cataract surgery (group 3) were studied. INTERVENTION: The thermal mode of the Lasag Microrupter II Nd:YAG laser was used to treat the filtering blebs. The area of the bleb targeted for treatment was "painted" with methylene blue and then exposed to Nd:YAG laser treatment with an energy level of 2.5 to 3.75 J in a grid pattern. The aiming beam was focused on the conjunctiva, but the laser beam was offset according to the height of the bleb (offset of 0.9-1.5 mm, 4-5 on the Lasag) to selectively treat the internal surface of the bleb. MAIN OUTCOME MEASURES: Symptomatology, intraocular pressure (IOP), and complications were measured. RESULTS: After the laser treatment, all the leaks in group 1 were healed, all the patients in group 2 reported relief of their symptoms, and all blebs in group 3 shrank considerably. The IOP increased significantly (P < 0.001) after laser treatment in all three groups. This elevation appeared to diminish over time, with the major increase in IOP being recorded within the first month after the laser treatment. However, satisfactory IOP control was maintained in nearly all patients (13 to 14) who received none or one antiglaucoma medication. The visual acuity of one patient decreased significantly because of cataract formation. Complications included transient pressure rise (1 eye), bleb failure (1 eye), pupillary retraction toward the bleb (6 eyes), iatrogenic bleb leak (6 eyes), and cataract (1 eye). CONCLUSION: The continuous wave Nd:YAG laser is an effective tool for repairing bleb-related problems while maintaining successful filtration.

Aged↗
PubMed1997

Experimental and clinical study of detection of glioma at surgery using fluorescent imaging by a surgical microscope after fluorescein administration.

Total resection is the optimal treatment for malignant gliomas. However, an unexpected residual tumor mass is sometimes found on magnetic resonance imaging performed after an operation because of a macroscopically unclear margin of the tumor at surgery. This study was designed to evaluate the effectiveness of fluorescent imaging by a surgical microscope after fluorescein administration for the detection of gliomas at surgery. For this study, we produced two filters for the excitation and emission of fluorescein that can be easily fitted to and removed from a surgical microscope manually during the operation. For the experimental study, Wistar rat brains bearing C6 glioma were removed at appropriate intervals after intravenous administration of 10-20 mg kg-1 body weight of sodium fluorescein, and their surface and coronal section through the tumor were observed using a surgical microscope with the filters. In clinical cases, 1000 mg of sodium fluorescein was intravenously administered to five patients with glioma before tumor resection. In the experimental study, the C6 glioma itself and the edematous brain adjacent to the tumor (within 2-3 mm of the gross surface of the tumor) were well stained a brilliant yellowish green for a few hours. The normal brain was not stained. In clinical cases, the tumors were stained a brilliant yellowish green under fluorescent observation at surgery. The patients had no side effects. At all times the fluorescent observation could be quickly changed to ordinary observation by removing the filters from the surgical microscope. The tumor was also stained a faint yellow under ordinary nonfluorescent observation. Although this contributed to detection of the tumor, the fluorescent staining demarcated the tumor more clearly than nonfluorescent staining. These results suggest that this imaging technique by a surgical microscope with special filters at surgery may be practical and useful for detection of gliomas and warrants further clinical evaluations.

Animals↗
PubMed1977

[Considerations on surgery of the iris (author's transl)].

Surgery of the iris is of essential importance in anterior segment surgery. In angle closure glaucoma a peripheral iridectomy performed early enough, when the trabeculum is not yet altered, is curative. In simple glaucoma if a filtering operation is performed, the iridectomy is fundamental in order to have a good communication between the posterior chamber and the filtering bleb and to avoid iris incarceration into the filtering wound. In cataract surgery iridectomy is mandatory, especially in intracapsular extraction. In penetrating corneal grafts a patent iridotomy or iridectomy, or several, is a safety factor avoiding the consequences of pupillary block, anterior synechiae and irreducible mydriasis. Another important problem is the surgery of the iris for optical purposes. Other indications which are not discussed in this paper are trauma of the anterior segment of the eye, the removal of benign or malignant tumors, epithelial cysts etc.

Cataract Extraction↗
PubMed2005

[Cataract and combined cataract/glaucoma surgery as intraocular pressure-reducing procedure in eyes with relative anterior microphthalmos].

PURPOSE: Eyes with relative anterior microphthalmos (RAM) (normal [> 20.0 mm] axial length but disproportionally small anterior segment [horizontal corneal diameter < 11 mm]) often present with increased intraocular pressure. Under these difficult conditions cataract surgery alone or in combination with a glaucoma filtering procedure is often required. PATIENTS AND METHODS: We retrospectively reviewed the records of 71 patients (108 eyes) with RAM in whom cataract only (n = 72) or combined cataract/glaucoma surgery (n = 36) was performed. Preoperative clinical and biometric findings, intraoperative complications and postoperative results (visual acuity and intraocular pressure) were analysed. RESULTS: Median preoperative values were 7.46 mm for corneal curvature, 2.53 mm for anterior chamber depth and 22.44 mm for axial length. The implanted lens had a median 25.0 dioptric power. The IOP was reduced from 15.6 +/- 3.9 mm Hg to 13.5 +/- 3.1 mm Hg with cataract surgery alone and from 22.4 +/- 5.5 mm Hg to 15.4 +/- 4.0 mm Hg with combined surgery. Mean best corrected visual acuity improved from 0.4 +/- 0.2 to 0.79 +/- 0.25 with cataract surgery and from 0.5 +/- 0.3 to 0.81 +/- 0.24 with combined surgery. Intraoperatively only 3 eyes had a rupture of the posterior capsule and postoperatively 2 eyes developed malignant glaucoma in the combined group. CONCLUSIONS: The results show that, in eyes with RAM, cataract surgery alone or in combination with glaucoma surgery can be performed with excellent results and low complication rate if adequate precautions are taken (especially the use of hyperosmotic agents).

Adult↗
PubMed1975

Upper eyelid retraction after glaucoma filtering procedures.

After glaucoma filtration surgery, 2 patients developed overaction of Müller's muscle with resultant upper eyelid retraction. We theorize that stimulation of Müller's muscle is caused by a sympathomimetic chemical in the aqueous that travels from the bleb, under the bulbar and palpebral conjunctiva, to Muüller's muscle. In one case excision of Muüller's muscle relieved the retraction. In the other case, preventing aqueous from reaching Müller's muscle reduced the retraction.

Aged↗
PubMed2001

Glaucoma filtration surgery using amniotic membrane transplantation.

PURPOSE: To investigate the potential use of amniotic membrane transplantation (AMT) in the construction of glaucoma filtering blebs. METHODS: Twenty-four albino rabbits underwent glaucoma filtration surgery in one eye. In alternate cases, the conjunctival flap was replaced with AMT. Postoperative examination data were grouped into three time points. Six animals with AMT and six filtration surgery-controls were euthanatized at each of two postoperative time points, and tissue was obtained for histologic examination. Conjunctival biopsies were explanted for estimation of fibroblast outgrowth. RESULTS: Bleb formation was observed in all eyes, and amniotic membranes were epithelialized after 11.2 +/- 2.48 (mean +/- SD) days. Throughout the study IOPs were significantly lower in operated than unoperated fellow eyes. Between postoperative days 11 and 16 (the middle time point), the percentage IOP reduction in AMT eyes was significantly greater than in filtration surgery controls (P = 0.014), though not at other time points. Filtration surgery survival was significantly longer in the AMT group (22.3 +/- 3.8 days; mean +/- SE) than in "No AMT" controls (14.0 +/- 1.6 days; P = 0.035). In tissue culture, significantly less fibroblast outgrowth occurred from AMT explants when compared with unoperated conjunctiva (P = 0.01) between postoperative days 3 and 9 (the early time point). Amniotic membrane transplants were intact on histologic examination after 14 days but were associated with considerable granulomatous inflammation. After 36 days, the ocular surfaces remained clinically intact, but lysis of AMT was noted histologically. CONCLUSIONS: AMT exhibits potential as an alternative tissue to conjunctiva in the construction of glaucoma filtration blebs. The healing response as demonstrated by fibroblast outgrowth is retarded when compared with conventional conjunctival closure. The improvement in bleb survival must be weighed against the potential for complications related to delayed healing. In rabbits, human amniotic membrane elicited a late xenograft reaction, leading to granulomatous inflammation and dissolution of the membrane.

Amnion↗
PubMed1984

Body surface late potentials: effects of endocardial resection in patients with ventricular tachycardia.

We studied 37 patients undergoing endocardial resection for medically refractory ventricular tachycardia (VT). Each was studied before and after surgery by programmed ventricular stimulation and signal-averaged electrocardiography. Low-amplitude late potentials were identified preoperatively in 76% of patients. In the 24 patients without postoperative VT the effect of surgery was to shorten the filtered QRS duration (137 +/- 27 to 121 +/- 26 msec; p = .003), increase the voltage in the last 40 msec of the filtered QRS (16.5 +/- 16.1 to 39.0 +/- 29.4 microV; p = .003), and decrease the incidence of late potentials (71% to 33%; p = .03). The filtered QRS complex was unchanged in 13 patients whose VT persisted after surgery. No preoperative variable predicted which patients would not have inducible VT after surgery. However, loss of a late potential after surgery in nine of 10 patients was associated with absence of inducible VT (p less than .02). Loss of a late potential was not necessary for surgical success. Eight of 18 patients with a persistent late potential did not have inducible VT. The signal-averaged electrocardiogram predicted a successful outcome after endocardial resection if the late potential was no longer present.

Cardiac Pacing, Artificial↗
PubMed1996

Retinal irradiation from an operating microscope during vitrectomy: observation by endoscopy.

Phototoxic retinopathy due to light from the operating microscope has been reported during cataract surgery, as well as during vitreous surgery. A neutral density filter for the coaxial light or coverage of the cornea with various materials has been advocated to prevent retinal complications. However, it is difficult to actually monitor the fundus during surgery with usual methods. The author used an endoscope to demonstrate how intensively the light from the operating microscope is focused on the retinal surface during vitreous surgery.

Endoscopy↗