Search PubMed⌕ Search

Biomedical subjects

A Mermoud

Publications and source records attributed to A Mermoud.

At least 19 recordsLinked to original sources
PubMed2006

[Dosage and kinetics of MMC release of a collagen implant used as a delivery device in glaucoma surgery in the rabbit eye].

PURPOSE: To determine the absorption and the release of mitomycin-C from a collagen implant and tissue impregnation in the anterior structures of the rabbit eye. METHODS: Determining the quantity of mitomycin-C that a collagen implant can absorb with the difference between dry and soaked weight. Mitomycin-C release was measured in vitro using spectrophotometry. The measurement was repeated using a bioassay. Ocular tissue impregnation was determined in 12 eyes of six rabbits. Sclera, implant, aqueous, and ciliary body specimens were collected for concentration measurement using HPLC from 1 to 6 h after surgery. RESULTS: The mean mitomycin-C quantity absorbed in the implant was 3.22+/-0.2 microg. In vitro release was 0.13 mg/ml after 10 min and 0.05 microg/ml at 6 h. The bioassay showed almost no antifibrotic activity in sclera. In vivo release of mitomycin-C was high from the first to the sixth hour. CONCLUSION: After filtering surgery, mitomycin-C in the collagen implant is clearly released and ocular tissues are effectively impregnated.

Animals↗
PubMed2006

[Deep nonpenetrating sclerectomy: technical aspects].

Classical trabeculectomy is affected by numerous and serious drawbacks that have led to the development of nonpenetrating surgery. In this new filtering technique, the aqueous outflow through the juxtacanalicular trabeculum and Schlemm's canal is selectively increased without penetrating the anterior chamber. This is best performed by means of a careful and precise dissection of the outflow resistance pathway and by removing its most resistant portion. This requires both mastery of the microdissection technique and high-precision surgical tools. Finally, sound knowledge of the morphological features of such delicate structures is of paramount importance to avoid intra- and postoperative complications.

Glaucoma↗
PubMed2006

[How does nonpenetrating surgery work?].

The aqueous leaves the anterior segment via two different pathways, the classical and the uveoscleral routes. The main resistance to aqueous egress lies at the level of the juxtacanalicular trabeculum and the inner wall of Schlemm's canal. Impaired function of either one of these structures leads to a decrease in the outflow facility which eventually results in a significant increase in intraocular pressure. Success of non-penetrating surgery lies in the physical removal of these resisting elements without compromising of the structural integrity of the eye, thus preventing a sudden drop in the intraocular pressure. The selective filtration through the trabeculodescemetic membrane, the evacuation of the aqueous in the intrascleral space, the subconjunctival bleb and the subchoroidal space, and the final drainage into collector channels and drain veins are the key elements for a successful deep sclerectomy.

Humans↗
PubMed2006

[Adjuvants to nonpenetrating surgery: drains and implants].

The nonpenetrating filtering procedure requires a functioning intrascleral space. This space is created after a careful dissection and resection of the deep scleral flap. In order to prevent a collapse of the remaining superficial flap that forms the roof of the intrascleral cavity, a space maintainer is usually inserted at this stage of surgery. Two different types of drainage devices are used: absorbable and nonabsorbable implants. The first type is currently made of porcine collagen material that is slowly absorbed over time, whereas the second is usually made of nondegradable materials that permanently remain in the scleral bed. No significant differences in the surgical technique can be found between the two types of implant. The long-term results are fairly similar for both of them, the absorbable implant being slightly more advantageous.

Dissection↗
PubMed2006

[Complications of deep nonpenetrating sclerectomy].

The typical complications related to nonpenetrating surgery are the rupture of the trabeculodescemetic membrane; postoperative ocular hypertension, which requires a laser goniopuncture; fibrosis of the filtering bleb, which is best cured by local antimetabolite application; or the development of a polycystic bleb, which is efficiently resolved by needling. While small perforation of the trabeculodescemetic membrane can be handled using simple countermeasures, large breaks ultimately result in converting the surgery into a penetrating procedure akin to trabeculectomy. Other classical complications can arise that comprise shallow anterior chamber, positive Seidel, hyphema, severe inflammation, choroidal detachment, or prolonged hypotony with associated maculopathy. They can occur in other types of filtering surgery as they are not specific to the nonpenetrating procedure and they differ only in prevalence.

Glaucoma↗
PubMed2005

Deep sclerectomy in one eye vs deep sclerectomy with collagen implant in the contralateral eye of the same patient: long-term follow-up.

PURPOSE: To compare prospectively the results of deep sclerectomy (DS) vs deep sclerectomy with collagen implant (DSCI). METHODS: Randomized prospective trial involving 26 eyes (13 patients) with medically uncontrolled primary and secondary open angle glaucoma. Collagen implant was randomly assigned to one eye of each patient. RESULTS: The mean follow-up period was 49.5 (SD 20) months for the DS-treated eyes, and 56.5 (SD 14) months for the DSCI-treated eyes (P=0.4). The mean preoperative intraocular pressure (IOP) was 24.1 (SD 7) mmHg for the DS-treated eyes, and 25.3 (SD 6) mmHg for the DSCI-treated eyes (P=0.5). The mean IOP at the first postoperative day was 6.4 (SD 3) mmHg for the DS-treated eyes, and 3.7 (SD 2) mmHg for the DSCI-treated eyes (P=0.05). The mean IOP at 12 months postoperative day was 15.4 (SD 3) mmHg for the DS group, and 10.4 (SD 4) mmHg for the DSCI-treated eyes (P=0.04), while at 48 months it was 16 (SD 3) mmHg for the DS group, and 10 (SD 4) mmHg for the DSCI-treated eyes (P=0.005). Complete success rate, defined as an IOP lower than 21 mmHg without medication, was 38% (5/13 patients) at 48 months for the DS-treated eyes, and 69% (9/13 patients) for the DSCI-treated eyes. Qualified success rate: patients who achieved IOP below 21 mmHg with or without medication, was 69% (9/13 patients) at 48 months and 100% (13/13 patients) for the DSCI group. The mean number of medications was reduced from 2.4 (SD 0.8) to 1.1 (SD 1) after DS, and was reduced from 2.2 (SD 0.7) to 0.4 (SD 0.6) in the DSCI group (P=0.001). For those eyes treated with DSCI, IOP was 3.21 mmHg lower than for those treated with DS (P<0.0001). CONCLUSION: The use of a collagen implant in DS seems to enhance the success rates, provides significantly lower IOP levels, and lowers the need for postoperative medications.

Aged↗
PubMed2005

Ex-PRESS implant.

Explore the source record for details and available documents.

Filtering Surgery↗
PubMed2004

Deep sclerectomy for the management of uncontrolled uveitic glaucoma: preliminary data.

BACKGROUND: If medical treatment fails in uveitic glaucoma a surgical approach should be considered. Classical trabeculectomy is known to have a less favourable outcome in uveitis. Our intention is to report the first series of uveitis patients with glaucoma resistant to medical therapy who were treated with deep sclerectomy (DS). PATIENTS AND METHODS: Fourteen eyes of 13 patients (mean age 39.0 +/- 18.5 years; range 8 to 76 years) with chronic uveitis underwent non-penetrating filtering surgery from 1995 to 2003. All patients had their uveitis controlled before and after surgery by immunomodulatory therapy. Non-penetrating filtering surgery consisted of DS with collagen implant (Staar(R)) in 4 eyes, DS with draining device (T-Flux Ioltech(R)) in 2 patients, DS without implant in 7 patients and with viscocanalostomy in 1 patient. Nine eyes (65 %) received mitomycin C peri-operatively. RESULTS: Intra-ocular pressure (IOP) was reduced from a mean pre-operative value of 42.8 +/- 13.6 mmHg to a 1-year mean post-operative value of 12.1 +/- 4.0 (71.7 % reduction). Eleven of the 14 eyes completed 12 months of follow-up, resulting in complete success in 5 (45.4 %) and in qualified success in 5 (45 %) and in failure in one patient (9.2 %), later controlled by a second operation. Anti-glaucomatous medication was reduced from a mean of 3.7 +/- 0.5 medications preoperatively to 1.2 +/- 0.8 medications (71.4 % reduction) at the 12 month follow-up. Nine of the 14 patients achieved a 24 month follow-up with a mean IOP of 14.1 +/- 3.8 mmHg and mean of anti-glaucomatous medications of 1.6. Four patients have been examined 4 years after the DS: mean IOP was 13.2 +/- 2.2 mmHg and mean medication 1.7 +/- 1.0. Post-operative complications included one case of lens opacity and 2 cases of hypotony lasting for five months and four weeks after the intervention respectively. CONCLUSION: Non-penetrating filtering surgery controlled the intra-ocular pressure in 90 % of eyes with uveitic glaucoma resistant to medical therapy at 12 months. Surgical complications were low which may explain the high success rate of the procedure, compared to classical penetrating surgery.

Adolescent↗
PubMed2004

T-Flux implant versus Healon GV in deep sclerectomy.

PURPOSE: To compare the efficacy and safety of T-Flux implant versus Healon GV in deep sclerectomy. METHODS: Randomized prospective trial of 23 eyes of 20 patients with medically uncontrolled open angle glaucoma over a period of 24 months, who underwent deep sclerectomy with either Healon GV or T-Flux implant. RESULTS: Mean postoperative intraocular pressure was 13.2 +/- 3.0 mm Hg with T-Flux implant (group 1) and 12.2 +/- 3.5 mm Hg with Healon GV (group 2), with a pressure reduction of 53.0% in group 1 (13.2 mm Hg vs. 28.1 mm Hg) and of 48.1% in group 2 (12.2 mm Hg vs. 23.5 mm Hg). Qualified and complete successes were 100% and 95.4% respectively. Pressures equal to or less than 15 mm Hg were 81.8% in group 1 and 90.9% in group 2 with or without treatment, and 63.6% in group 1 and 81.8% in group 2 without treatment. The number of glaucoma treatments dropped from 2.5 +/- 0.9 to 0.4 +/- 0.7 in group 1 and from 2.2 +/- 1.0 to 0.2 +/- 0.4 in group 2. The goniopuncture rate was 63.6% in group 1 and 36.4% in group 2, with a mean pressure drop of 6.1 +/- 3.9 mm Hg and 3.25 +/- 1.2 mm Hg respectively. Overall, slit-lamp diagnosed surgery-related complications included positive Seidel (13.6%), hyphaema (22.7%), choroidal detachment, and iris incarceration (4.5% each). At 2 years, ultrasound biomicroscopy showed mainly low reflective (40.1%) and flattened (36.4%) blebs. Principally latter ones were associated with the need for adjunctive treatment. A hypoechoic area in the suprachoroidal space was seen in at least 59.1% of eyes at 2 years and was not associated with lower intraocular pressure. CONCLUSION: Deep sclerectomy is an effective and safe surgery. However, longer follow up and larger study groups are required to assess the additional benefit of nonabsorbable implants.

Aged↗
PubMed2004

Low first postoperative day intraocular pressure as a positive prognostic indicator in deep sclerectomy.

AIM: To study the possibility of using intraocular pressure (IOP) in the first postoperative day after sclerectomy as a prognostic indicator. METHODS: Non-randomised prospective trial involving 105 eyes of 105 patients with medically uncontrolled primary and secondary open angle glaucoma. Visual acuity, IOP, and slit lamp examinations were performed before and after surgery at 1 and 7 days, and 1, 3, 6, 9, 12, 18, 24, 30, 36, 48, 54, 60, and 66 months. Visual field examinations were repeated every 6 months. A split point on day 1 IOP of less than or equal to 5 mm Hg (61%) versus more than 5 mm Hg (39%) was used. The first postoperative day IOP was examined in relation to the need for subsequent Nd:YAG goniopuncture, the subsequent use of postoperative antiglaucoma medications, and as a stratification variable in the Kaplan-Meier analyses. RESULTS: The mean follow up was 43.2 (SD 14.3) months. The mean preoperative IOP was 26.8 (SD 7.7) mm Hg; the mean postoperative IOP was 5.1 (3.3) mm Hg at day 1 and 11.8 (3.1) mm Hg at month 60. Patients with IOP </=5 mm Hg had significantly fewer Nd:YAG goniopunctures (p = 0.0478). A significant (log rank test 0.0122) improvement for those with IOP </=5 mm Hg in terms of survival was detected using the most stringent criterion (IOP </=15 mm Hg with no medications). For patients with first postoperative day IOP </=5 mm Hg, the median time to failure was 24 months (95% CI: 12 to 30), but for those with an IOP >5 mm Hg, the median time to failure was only 6 months (CI 2 to 9). No significant difference in postoperative antiglaucoma medications was observed. CONCLUSION: First postoperative day IOP can be considered to be a significant prognostic indicator in deep sclerectomy.

Antihypertensive Agents↗
PubMed2004

Influence of non-penetrating glaucoma surgery on aqueous outflow facility in isolated porcine eyes.

PURPOSE: To investigate, in vitro, the influence of non-penetrating glaucoma surgery (NPGS) and the influence of tightly suturing the superficial scleral flap on the aqueous outflow facility of isolated porcine eyes. MATERIALS AND METHODS: The anterior chambers of 12 enucleated porcine cadaver eyes were cannulated and perfused. NPGS was performed by the same surgeon. The overall ocular aqueous outflow facilities were assessed before and after the surgical interventions of NPGS, as well as after scleral flap closure. RESULTS: The mean (SD) aqueous outflow facility, which was 0.164 (0.014) microl/min/mm Hg before surgery, increased significantly after NPGS to 1.584 (0.217) microl/min/mm Hg, p<0.001. When the superficial flap was closed, the aqueous outflow facility significantly decreased (0.754 (0.107) microl/min/mm Hg, p<0.001) but remained significantly higher than preoperatively (p<0.01). After suturing the superficial flap, the overall resistance increased to 1.625 (0.210) microl/min/mm Hg. The difference in the resistance to outflow before and after flap closure was 0.848 (0.169) microl/min/mm Hg. CONCLUSION: After NPGS suturing the scleral flap can modulate aqueous outflow resistance. The experimental set up described might provide an efficient model for the technical training of glaucoma surgeries.

Animals↗
PubMed2004

Comparative study between deep sclerectomy with and without collagen implant: long term follow up.

AIM: To identify the value of using collagen implant in deep sclerectomy. METHODS: A prospective randomised trial of 104 eyes (104 patients) with medically uncontrolled primary and secondary open angle glaucoma. All patients had deep sclerectomy (DS), half of them with and the other half without a collagen implant (CI) sutured in the scleral bed. The main outcome measures were intraocular pressure (IOP), visual acuity, number of treatments preoperative and postoperative, and Nd:YAG goniopunctures. RESULTS: Mean follow up period was 44.5 (SD 21) months for the DS group and 43.9 (SD 14) months for the deep sclerectomy with a collagen implant (DSCI) group. The mean preoperative IOP was 23.3 (SD 7.2) mm Hg for the DS group and 25.6 (SD 4.9) mm Hg for the DSCI group. The mean IOP at the first postoperative day was 6.1 (SD 4.21) mm Hg for the DS group and 5.1 (SD 3.3) mm Hg for the DSCI group. At 48 months IOP was reduced by 40% (14 versus 23.3 mm Hg) for the DS group and by 50% (12.7 versus 25.6 mm Hg) for the DSCI group. Complete success rate, defined as IOP lower than 21 mm Hg without medication, was 34.6% (18/52 patients) at 48 months for the DS group, and 63.4% (33/52 patients) for the DSCI group. Qualified success rate; patients who achieved IOP below 21 mm Hg with or without medication, was 78.8% (41/52 patients) at 48 months and 94% (49/52 patients) for the DSCI group. The mean number of medications was reduced from 2.1 (SD 0.8) to 1.0 (SD 1) after DS, and was reduced from 2.2 (SD 0.7) to 0.4 (SD 0.6) in the DSCI group (p = 0.001) CONCLUSION: The use of a collagen implant in DS enhances the success rates and lowers the need for postoperative medication.

Aged↗
PubMed2003

Aqueous dynamic and histological findings after deep sclerectomy with collagen implant in an animal model.

AIM: The use of an animal model to study the aqueous dynamic and the histological findings after deep sclerectomy with (DSCI) and without collagen implant. METHODS: Deep sclerectomy was performed on rabbits' eyes. Eyes were randomly assigned to receive collagen implants. Measurements of intraocular pressure (IOP) and aqueous outflow facility using the constant pressure method through cannulation of the anterior chamber were performed. The system was filled with BSS and cationised ferritin. Histological assessment of the operative site was performed. Sections were stained with haematoxylin and eosin and with Prussian blue. Aqueous drainage vessels were identified by the reaction between ferritin and Prussian blue. All eyes were coded so that the investigator was blind to the type of surgery until the evaluation was completed. RESULTS: A significant decrease in IOP (p<0.05) was observed during the first 6 weeks after DSCI (mean IOP was 13.07 (2.95) mm Hg preoperatively and 9.08 (2.25) mm Hg at 6 weeks); DS without collagen implant revealed a significant decrease in IOP at weeks 4 and 8 after surgery (mean IOP 12.57 (3.52) mm Hg preoperatively, 9.45 (3.38) mm Hg at 4 weeks, and 9.22 (3.39) mm Hg at 8 weeks). Outflow facility was significantly increased throughout the 9 months of follow up in both DSCI and DS groups (p<0.05). The preoperative outflow facility (OF) was 0.15 (0.02) micro l/min/mm Hg. At 9 months, OF was 0.52 (0.28) microl/min/mm Hg and 0.46 (0.07) micro l/min/mm Hg for DSCI and DS respectively. Light microscopy studies showed the appearance of new aqueous drainage vessels in the sclera adjacent to the dissection site in DSCI and DS and the apparition of spindle cells lining the collagen implant in DSCI after 2 months. CONCLUSION: A significant IOP decrease was observed during the first weeks after DSCI and DS. DS with or without collagen implant provided a significant increase in outflow facility throughout the 9 months of follow up. This might be partly explained by new drainage vessels in the sclera surrounding the operated site. Microscopic studies revealed the appearance of spindle cells lining the collagen implant in DSCI after 2 months.

Animals↗
PubMed2003

Five year results of viscocanalostomy.

AIM: To prospectively study the success rate and complications of viscocanalostomy, a non-penetrating glaucoma surgery. METHODS: Prospective non-randomised consecutive case series of 57 eyes (57 patients) with medically uncontrolled primary and secondary open angle glaucoma. Viscocanalostomy was performed on all participants with injection of viscoelastic in the surgically created ostia of Schlemm's canal as well as in the scleral bed, the superficial scleral flap was loosely sutured. Intraocular pressure, visual acuity, and number of goniopunctures were measured. RESULTS: The mean follow up period was 34.1 months. The mean preoperative intraocular pressure (IOP) was 24.6 mm Hg; while the mean postoperative IOP was 5.6 mm Hg at day 1 and 13.9 mm Hg at 36 month. Patients who achieved IOP below 21 mm Hg with or without medication were 90% at 60 months, complete success rate (IOP<21 mm Hg without medication) was 60% at 60 months. 21 patients (37%) needed Nd:YAG goniopuncture postoperatively to control raised IOP, mean time for goniopuncture application was 9.4 months, mean pre-goniopuncture IOP was 20.4 mm Hg and mean postgoniopuncture IOP was 12.6 mm Hg (p <0.0001). CONCLUSION: Viscocanalostomy appears to be a promising modification of filtering surgery.

Aged↗
PubMed2003

Four years later: a clinical update on latanoprost.

PURPOSE: Almost five years have elapsed since the introduction of latanoprost on several markets and considering the large number of publications dealing with it, the authors felt that it was worth re-evaluating the drug. METHODS: The criterion used to select trials for inclusion in the review was: all articles mentioning the drug in common electronic data-bases; these were then screened and considered, on the basis of methodological quality. RESULTS: Experimental data suggest that latanoprost acts by remodeling the extracellular matrix in the ciliary muscle, thus increasing the flow of aqueous humor through the ciliary muscle bundles of the uveoscleral pathway. POAG: Latanoprost persistently improves the pulsatile ocular blood flow in primary open angle glaucoma (POAG). Recent trials confirmed the greater IOP-lowering efficacy of latanoprost vs. timolol, dorzolamide, brimonidine and unoprostone. Trials lasting up to 24 months showed that latanoprost is effective in long-term treatment of POAG and ocular hypertension (OH), with no signs of loss of efficacy when compared to timolol or dorzolamide. Latanoprost provides better control of circadian IOP. Non-responders to beta-blockers should preferably be switched to latanoprost monotherapy before a combination therapy is started. The possibility of a fixed combination of latanoprost and timolol has been explored, with promising results. NTG: Latanoprost is effective in normal tension glaucoma (NTG), lowering IOP, improving pulsatile ocular blood flow and increasing ocular perfusion pressure. OTHER GLAUCOMAS: Latanoprost may provide effective IOP control in angle-closure glaucoma after iridectomy, in pigmentary glaucoma, glaucoma after cataract extraction and steroid-induced glaucoma. However, latanoprost was effective in only a minority of pediatric cases of glaucoma and is contraindicated in all forms of uveitic glaucoma. SAFETY: In the articles reviewed, new or duration-related adverse events were reported.

Antihypertensive Agents↗
PubMed2002

Free conjunctival autologous graft for bleb repair and bleb reduction after trabeculectomy and nonpenetrating filtering surgery.

PURPOSE: To describe methods and outcomes of excisional revision of a filtering bleb (bleb revision) using free conjunctival autologous graft either for bleb repair or for bleb reduction after trabeculectomy and deep sclerectomy with an implant. METHODS: Retrospective medical records were reviewed for a consecutive non-comparative case series comprising patients who underwent excisional revision of a filtering bleb between May 1998-January 2001. Excisional revision using free conjunctival autologous graft (bleb revision) was performed either for bleb repair, to treat early and late leaks and hypotony with maculopathy, or for bleb reduction, to improve ocular pain, discomfort, burning, foreign body sensation, tearing, and fluctuations of visual acuity. The revision consisted of bleb excision and free conjunctival autologous graft. The bleb histopathology was analyzed in patients who underwent bleb repair. RESULTS: Sixteen patients were included in the study, consisting of nine patients who had a trabeculectomy and seven patients who had a deep sclerectomy with an implant. Bleb revision was necessary in 14 patients due to leaking filtering bleb (bleb repair), and in 2 patients due to bleb dysesthesia (bleb reduction). After a follow-up of 15.1 +/- 8.4 months, the mean intraocular pressure (IOP) rose from 7.8 +/- 6.3 mm Hg to 14.3 +/- 6.5 mm Hg, and the visual acuity from 0.4 +/- 0.3 to 0.7 +/- 0.3, with a P value of 0.008 and 0.03, respectively. The complete success rate at 32 months, according to the Kaplan-Meier survival curve, was 38.3%, and the qualified success rate was 83.3%. Four patients (25%) required additional suturing for persistent bleb leak. To control IOP, antiglaucoma medical therapy was needed for six patients (37.5%) and repeated glaucoma surgery was needed for one patient. CONCLUSION: Free conjunctival autologous graft is a safe and successful procedure for bleb repair and bleb reduction. However, patients should be aware of the postoperative possibility of requiring medical or surgical intervention for IOP control after revision.

Adult↗
PubMed2002

Descemet membrane detachment after nonpenetrating filtering surgery.

PURPOSE: To make surgeons performing nonpenetrating filtering surgery aware of an unusual complication namely Descemet membrane detachment. METHODS: We retrospectively reviewed nine eyes of nine patients seen in our hospital with Descemet membrane detachment occurring after nonpenetrating filtering surgery from January 1994 to December 2000. RESULTS: Both planar and nonplanar detachments were reported. Neither scrolls nor tears in the Descemet membrane were observed in any patient. After viscocanalostomy (four patients), the detachment was generally noticed shortly after the procedure and the cornea maintained its clarity. After deep sclerectomy with a collagen implant (five patients), it developed weeks to months postoperatively with adjacent corneal edema. Four patients had descemetopexy. None required more than one procedure. However, at the last visit, two detachments persisted although they had diminished in size: one after viscocanalostomy and conservative treatment and one after descemetopexy after deep sclerectomy with a collagen implant. To date otherwise, no signs of significant corneal damage could be observed clinically nor by specular microscopy and pachymetry. CONCLUSIONS: The diagnosis of Descemet membrane detachment can be easily overlooked or misdiagnosed. The clinical presentation, clinical course, and pathogenesis depend on the type of nonpenetrating filtering surgery performed. Ophthalmologists should be aware of this unusual complication, which is likely to be more common after nonpenetrating filtering surgery than after trabeculectomy. A period of observation before attempting descemetopexy is recommended.

Adult↗