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Biomedical subjects

D K Heuer

Publications and source records attributed to D K Heuer.

At least 19 recordsLinked to original sources

Fascia lata patch graft in glaucoma tube surgery.

PURPOSE: To determine if using human cadaveric fascia lata grafts to cover glaucoma implant tubes is safe and effective. METHODS: All patients who underwent glaucoma implant surgery at the Doheny Eye Institute between July 1993 and September 1993 received a fascia lata patch graft to cover the subconjunctival portion of the tube. These patients were followed prospectively for clinical signs of conjunctival breakdown, graft melt, tube erosion, graft-related inflammation, infection, and graft-related complications. RESULTS: Twenty-two eyes of 21 patients were followed for a mean of 19 months. All eyes tolerated the fascia lata grafts well without clinical evidence of graft-related conjunctival, scleral, or intraocular inflammation. No tube erosion or melting of the graft was observed in the study group. CONCLUSION: Preserved donor fascia lata was well tolerated as a grafting material in glaucoma implant surgery. No clinical signs of graft rejection, foreign body reaction, tube erosion, or graft melt were observed in the study group during the follow-up period.

Adolescent

Laser suture lysis after mitomycin C trabeculectomy.

PURPOSE: To evaluate the timing, efficacy, and complications of laser suture lysis (LSL) after mitomycin C trabeculectomy in patients with glaucoma at high risk for failure of filtering surgery. METHODS: The authors retrospectively reviewed the charts of 62 consecutive patients who underwent a total of 66 sessions of LSL after trabeculectomy with mitomycin C. RESULTS: The interval from surgery to LSL ranged from 2 to 65 days (mean +/- standard deviation, 17.9 +/- 14.9 days). The average intraocular pressure (IOP) reduction after LSL was 11.9 +/- 8.9 mmHg (range, 3-40 mmHg). A longer interval to LSL was correlated with a lesser degree of pressure reduction (P=0.0004, Wilcoxon rank-sum test). After LSL, hypotony developed in 13 (21%) patients (IOP < 6 mmHg on 2 consecutive measurements at least 24 hours apart). This resolved spontaneously after 7 to 304 days (104.1 +/- 109.1 days) in 12 (92%) of the 13 patients. Life-table success rates (success defined as 6 mmHg </= final IOP </= 21 mmHg) for the hypotony and no hypotony groups were 100% and 86% (at 6 months) and 96% and 86% (at 12 months), respectively. The final visual acuity worsened in a significantly greater percentage of patients in the hypotony group (46%) compared with the no-hypotony group (18%) (P = 0.06), Fisher's exact test). CONCLUSIONS: Laser suture lysis is safe and effective in augmenting aqueous filtration after mitomycin C trabeculectomy. A longer time interval between surgery and LSL may result in both a lesser degree of IOP reduction and a lower incidence of subsequent hypotony.

Adolescent

Intracameral tissue plasminogen activator after glaucoma surgery. Indications, effectiveness, and complications.

PURPOSE: To describe the authors' clinical experience with intracameral tissue plasminogen activator (tPA) after glaucoma surgery. METHODS: Retrospective review of medical records of all patients who received intracameral tPA after glaucoma surgery at the Doheny Eye Institute from November 4, 1992, to June 14, 1994. There were 20 tPA administrations (18 eyes of 17 patients) in doses ranging from 6 to 25 microgram. Indication for tPA administration was decreased bleb function secondary to blood/fibrin clot in aqueous outflow pathway. RESULTS: Tissue plasminogen activator was given after trabeculectomy (5 drug administrations) and combined cataract extraction/trabeculectomy procedures (9 drug administrations), with increased filtration in 12 (86%). There were five (36%) instances of hyphema and three (21%) of hypotony. All hyphemas occurred after doses of 25 microgram. Final IOP of 18 mmHg or lower and 6 mmHg or higher was achieved in 11 (92%) of 12 patients after a mean follow-up interval of 4.2+/-4.7 months. The six remaining tPA irrigations were done in five patients after glaucoma drainage implant surgery (n=4) or surgical/needle revision of a filtering bleb (n=2). CONCLUSIONS: Aqueous outflow obstruction from blood/fibrin clot after glaucoma surgery may be treated effectively with intracameral tPA in doses of 6 to 25 microgram. The authors recommend using a dose of less than or equal to 6 to 12.5 microgram to minimize risk of hyphema.

Adolescent

Suprachoroidal hemorrhage after Molteno implantation.

PURPOSE: The objective of this study is to identify the rate and the associated risk factors for suprachoroidal hemorrhage (SCH) after Molteno drain implantation. METHODS: Data from the Molteno pilot study and single versus double-plate Molteno study were reviewed retrospectively for the occurrence of SCH. Follow-up intervals, demographic variables, ocular data, and medical history were collected. RESULTS: SCH occurred in 6% of the patients enrolled in the Molteno studies; all cases were delayed and none were intraoperative. Significantly associated factors in a multiple logistic regression for SCH were the extent of intraocular pressure (IOP) drop after surgery, the post-operative IOP, a diagnosis of angleclosure glaucoma, and possibly the number of prior surgeries as well. Eyes with SCH did significantly less well in terms of visual acuity outcomes and were more likely to have inadequately controlled IOP. CONCLUSIONS: This study suggests that SCH occurs at the same frequency after Molteno implantation as after filtering surgery with antimetabolite use and that eyes with SCH do less well.

Adult

Pars plana Baerveldt tube insertion with vitrectomy in glaucomas associated with pseudophakia and aphakia.

PURPOSE: We reviewed the course of intraocular pressure, visual acuity, and complications in patients with shallow anterior chambers or vitreous prolapse who underwent insertion of glaucoma drainage tubes through the pars plana (after a complete posterior vitrectomy). METHODS: Thirteen patients (13 eyes) with uncontrolled glaucoma associated with shallow anterior chamber or vitreous prolapse and aphakia or pseudophakia underwent pars plana Baerveldt tube insertion after vitrectomy. RESULTS: In 11 eyes the intraocular pressure was less than or equal to 15 mm Hg at a minimum follow-up of one year; the other two eyes underwent additional glaucoma surgery. Two of the 11 eyes with controlled intraocular pressure had limitation of ocular motility postoperatively. No retinal complications had occurred in any of the 13 eyes. CONCLUSION: This technique of combined pars plana vitrectomy and pars plana insertion of a Baerveldt tube provides intraocular pressure control in eyes with shallow anterior chamber or vitreous prolapse and glaucoma associated with pseudophakia or aphakia.

Adolescent

Krupin disk implantation for complicated glaucomas.

BACKGROUND: The Krupin Eye Valve with Disk (Krupin disk) is a glaucoma shunt that incorporates a slit valve intended to minimize early postoperative hypotony. METHODS: The medical records of all patients who have undergone Krupin disk implantation at the Doheny Eye Institute between July 1990 and December 1992 (25 eyes of 25 patients) were reviewed. RESULTS: Intraocular pressure (IOP) was reduced from a mean of 36.1 +/- 11.5 mmHg to 15.3 +/- 7.5 mmHg at follow-up intervals of 4 to 19 months (mean, 13.2 months). On the first postoperative day, IOPs ranged from 0 to 40 mmHg. In two eyes (8%), the IOP was less than 6 mmHg, and in five eyes (20%) the IOP was more than 21 mmHg. Serous choroidal effusion and/or choroidal hemorrhage occurred in seven patients (28%). Six- and 12-month life-table success rates (6 < or = IOP < or = 21 mmHg) were 84% and 66%, respectively. CONCLUSION: The Krupin disk lowers IOP in most patients; however, the presence of a slit valve does not eliminate either early postoperative hypotony with its attendant complications or early IOP spikes.

Adolescent

Intermediate-term results of a randomized clinical trial of the 350- versus the 500-mm2 Baerveldt implant.

BACKGROUND: The Baerveldt glaucoma implant is a large equatorial aqueous shunting device that is installed through a single-quadrant conjunctival incision. The intermediate-term results of a randomized study comparing the 350- and 500-mm2 Baerveldt implants are reported. METHODS: Seventy-three patients with medically uncontrollable, nonneovascular glaucomas associated with aphakia, pseudophakia, or failed filters were enrolled in a randomized, prospective study comparing 350- and 500-mm2 Baerveldt implants. Surgical success was defined as 6 mmHg < or = final intraocular pressure < or = 21 mmHg without glaucoma reoperation or devastating complication. RESULTS: Of patients with 350- and 500-mm2 implants, 93% and 88%, respectively, achieved surgical success (18-month life-table analysis, P = 0.93). The 500-mm2 implants afforded intraocular pressure control with significantly fewer medications (0.7 versus 1.3; P = 0.006). The postoperative visual acuities remained within one line of the preoperative visual acuities or improved in 62% and 66% of patients in the 350- and 500-mm2 groups, respectively (P = 0.93). Complication rates were statistically similar. The most frequent ones in the 350- and 500-mm2 groups, respectively, were serous choroidal effusion (16% and 32%), strabismus (16% and 19%), anterior uveitis (14% and 11%), and corneal or corneal graft edema (11% each). CONCLUSION: The intermediate-term results of the 350- and 500-mm2 Baerveldt implants were statistically comparable with respect to surgical and visual outcomes, as well as complications, although the larger implant was associated with a higher rate of some complications. However, the 500-mm2 Baerveldt implant afforded intraocular pressure control with fewer medications than the 350-mm2 implant.

Adolescent

Aqueous tube shunt to a preexisting episcleral encircling element in the treatment of complicated glaucomas.

PURPOSE: The treatment of glaucoma after scleral buckling surgery is often problematic. The authors investigated a series of patients in whom a silicone tube was implanted to shunt aqueous from the anterior segment to the fibrous capsule surrounding a previously placed silicone episcleral encircling element. METHODS: Thirteen patients were retrospectively reviewed. In each patient, a silicone tube was inserted through a small incision into the fibrous capsule overlying the scleral explant. In most patients, no attempt was made to secure the distal end of the tube to the silicone band. The proximal end of the tube was inserted into the eye via a needle track. RESULTS: Successful control of intraocular pressure (IOP) (6 mm Hg < or = final IOP or < 21 mmHg with or without medication) was ultimately achieved in 11 (85%) of 13 patients (3 of the successful patients underwent one or more surgical revisions to relieve obstruction of the proximal and/or distal tube opening). Follow-up in these patients ranged from 8 to 49 months (mean +/- standard deviation, 21.7 +/- 14.1 months). The final postoperative visual acuities were within one line of the preoperative visual acuities or had improved in 11 (85%) patients. Complications included serous choroidal detachment (3 patients; 23%), conjunctival wound leak (2 patients; 15%), hyphema (1 patient; 8%), and tube obstruction by lens, iris, vitreous, or episcleral fibrous tissue (4 patients; 31%). CONCLUSION: Aqueous tube shunt to a pre-existing episcleral encircling element is useful in treating complicated glaucomas after scleral buckling surgery. Fibrous obstruction of the external tube opening is a frequent complication in the early postoperative period, but it may be relieved by surgical revision.

Adult

Epithelial ingrowth and glaucoma drainage implants.

BACKGROUND: The authors report four cases of conjunctival epithelial invasion into the fibrous capsule surrounding a Baerveldt glaucoma implant. All cases were associated with concurrent or recent prior scleral buckling surgery. METHODS: Three patients had postoperative conjunctival wound leaks, one in the immediate postoperative period and the other two at 9 and 17 days postoperatively after release of the tube ligature. In the fourth patient, a fistulous tract developed over the implant after a first-stage insertion. Histopathologic confirmation of subconjunctival epithelialization was obtained in two of these patients. RESULTS: Surgical revision was performed in all patients. Excision and debridement of all epithelium-lined subconjunctival tissues and extensive bipolar cautery were used in the three patients with wound leaks. Implant removal also was performed in one of these. Fistulectomy and bipolar cautery were used in the fourth patient. No recurrent wound leaks or other adverse sequelae were noted. CONCLUSIONS: Epithelial invasion of the subconjunctival space and inner bleb wall after implantation of glaucoma drainage devices can lead to breakdown of the conjunctival wound and persistent aqueous leak. Prior or concurrent scleral buckling surgery may predispose to this occurrence. Surgical revision involving epithelial debridement, cautery, and meticulous wound closure, with or without implant removal, has been used successfully in the management of this complication.

Adult

Rhegmatogenous retinal detachment after Molteno glaucoma implant surgery.

BACKGROUND: The Molteno implant is a device used for surgical treatment of complicated glaucoma. Rhegmatogenous retinal detachment (RD) is a relatively rare complication of Molteno implant surgery. This study was undertaken to evaluate the clinical features including the surgical management and postoperative outcome of patients with rhegmatogenous RD after Molteno implant surgery. METHODS: The authors reviewed 350 consecutive patients who had Molteno surgery and identified 16 patients with subsequent rhegmatogenous RD. They also studied one patient referred for RD repair after Molteno surgery at another institution. RESULTS: The risk of rhegmatogenous RD was 5%. Seventy percent (12/17) of the patients presented within 4 months of the Molteno procedure. Dialysis and flap tear were the most common types of retinal break found. Forty-one percent (7/17) of the patients had proliferative vitreoretinopathy. In three patients, clinical features suggested RD resulting from the Molteno procedure. In other patients, previous ocular surgery and underlying ocular disease may have contributed to the development of RD. Retinal detachment repair was attempted in all patients. Among 16 patients with at least 6 months of follow-up, 56% (9/16) had successful retina attachment. Forty-four percent (7/16) of the patients maintained formed vision. Eighteen percent (3/16) of the patients maintained visual acuity of at least 20/40. Intractable glaucoma did not develop in any of the patients with an attached retina. Recurrent RD, endophthalmitis, cyclitic membrane, or intractable glaucoma led to phthisis bulbi or enucleation in 44% (7/16) of the patients. CONCLUSION: A combined approach by vitreoretinal and glaucoma surgeons can restore vision and maintain glaucoma control in patients with rhegmatogenous RD associated with Molteno implant surgery.

Adolescent

Initial clinical experience with the baerveldt implant in complicated glaucomas.

BACKGROUND: The Baerveldt glaucoma implant is an aqueous shunting device with a large surface area that is installed through a conjunctival incision in one quadrant of the eye. This study presents the initial results of the first 13 patients who underwent Baerveldt implantation as part of the Food and Drug Administration approval process. METHODS: Thirteen patients with medically uncontrollable complicated glaucomas underwent one-stage implantation of either a 200- or 350-mm2 Baerveldt implant without postoperative systemic antifibrosis therapy. Surgical success was defined as intraocular pressure greater than or equal to 6 and less than or equal to 21 mmHg without glaucoma reoperation or devastating complication. RESULTS: Eight patients (62%) had successful surgical outcomes, with a mean follow-up of 17.3 +/- 7.0 months (+/- standard deviation) (range, 6-24 months). Seven (70%) of the ten patients with glaucomas associated with aphakia or pseudophakia had successful outcomes, whereas only one (50%) of the two patients with neovascular glaucomas had a successful outcome. One patient with glaucoma associated with nanophthalmos and an unsuccessful filtering procedure had a failed outcome. The postoperative visual acuities remained within one line of the preoperative visual acuities or improved in 62% of the patients. The most frequent complications among all patients were transient serous choroidal effusion (23%) and hyphema (15%). CONCLUSION: Initial results of the Baerveldt implant generally are comparable with other implants. It is easier to install and requires less extensive conjunctival dissection than other large implants. Additional studies are needed to evaluate the effectiveness of the Baerveldt implant in affording long-term intraocular pressure control.

Adult

Echographic evaluation of glaucoma shunts.

BACKGROUND: It is frequently impossible to determine by clinical examination alone if a filtering bleb is present over the equatorial plate(s) of a glaucoma shunt. This uncertainty can result in management dilemmas when patients with these devices have elevated intraocular pressures (IOPs). The authors describe how standardized echography can be used to determine if fluid is present around the plates and to characterize the blebs. METHODS: Four hundred twenty-seven plates in 269 patients who had undergone single- or double-plate Molteno implantation underwent standardized echography (both A- and B-scan examinations) to determine if blebs were present around the plates, primarily when results of slit-lamp examinations had been inconclusive. Bleb sizes, locations, and characteristics also were evaluated. RESULTS: Sixty-five percent of the plates had associated blebs, which were graded according to their sizes (small, medium, and large, in 29%, 44%, and 27% of plates with blebs, respectively). Fluid (which appeared as an echolucent area) could be seen underlying and/or overlying the plates (which appeared as echodense lines). Larger blebs were often associated with scleral flattening. Although bleb sizes did not necessarily correlate with the levels of IOP control, the presence of a bleb on ultrasound was indicative of tube patency. CONCLUSION: Standardized echography was invaluable in the postoperative management of patients who had undergone Molteno implantation because it demonstrated the presence or absence of blebs and characterized them when results of slit-lamp examinations had been inconclusive. This technique also can be used to evaluate similarly designed aqueous shunting devices.

Adult

Trabeculectomy and Molteno implantation for glaucomas associated with uveitis.

PURPOSE: This study compares the outcomes of trabeculectomy and Molteno implantation in the treatment of glaucomas associated with uveitis. METHODS: Forty-five patients with uveitis, who had undergone filtering surgery for glaucomas associated with uveitis, were reviewed retrospectively. Successful outcome was defined as final intraocular pressure (IOP) of 6 to 21 mmHg, with a minimum follow-up of 6 months without visually devastating complications or loss of light perception. RESULTS: One- and two-year life-table success rates, respectively, were 81% and 73% with trabeculectomy (16 patients); 53% and 31% with combined trabeculectomy and first-stage (reserve) Molteno implantation (19 patients); and 79% and 79% with one-stage Molteno implantation (10 patients). In 11 patients who underwent second-stage Molteno implantation after trabeculectomy failure, 1- and 2-year life-table success rates were 79% and 79%, respectively. Complications included surgically treated choroidal effusions (1/45; 2%), choroidal hemorrhages (3/45; 7%), and chronic hypotony (3/45; 7%). Follow-up in all groups ranged from 5 to 70 months (mean +/- standard deviation, 28 +/- 17 months). CONCLUSIONS: Trabeculectomy provides surprisingly good results in glaucomas associated with uveitis (modulation of wound healing with antimetabolites probably would afford an even higher success rate). However, when significant, immediate postoperative and/or moderate chronic postoperative inflammation is likely, aqueous drainage devices appear more likely to control IOP.

Adult

Mitomycin-C concentration in human aqueous humour following trabeculectomy.

The aim of the study was to determine mitomycin-C (MMC) concentrations in human aqueous humour during trabeculectomy and to correlate anterior chamber concentrations with method of application. MMC was applied intra-operatively by saturating sponges, ranging in size from 2 x 2 x 5 mm to 2 x 4 x 10 mm on dry cut, with 0.5 mg/ml MMC during trabeculectomy for 3-5 minutes. Applications to episclera were made in 18 cases and to the scleral bed after scleral flap dissection in 9 cases. Aqueous samples were collected by paracentesis with a 30 gauge needle 2-7 minutes after removal of sponge and external irrigation. Aqueous MMC concentrations were determined by high-performance liquid chromatography. Aqueous MMC concentration in 27 samples ranged from below minimum detectable concentration (less than 5 ng/ml) to 120.8 ng/ml. Mean aqueous drug levels obtained when the applications were to the scleral bed were 35.65 +/- 39.17 ng/ml (range 5-120.8 ng/ml). Applications on episclera gave mean aqueous concentrations of 4.98 +/- 9.11 ng/ml (range 0-33.3 ng/ml). The difference was statistically significant (p = 0.004). There were no correlations between sponge size, time of MMC exposure and aqueous MMC level. In conclusion, MMC is detectable in aqueous humour within minutes of external application and the aqueous concentration level is higher if the application is in the scleral bed than on the episclera. Toxicity of the drug at this concentration range for corneal endothelial cells needs further investigation via in vitro and clinical studies.

Adolescent

Incidence and management of glaucoma after intravitreal silicone oil injection for complicated retinal detachments.

BACKGROUND: Intravitreal silicone oil injection used for managing complicated retinal detachments can be associated with elevated intraocular pressure (IOP). This study was undertaken to determine the incidence of glaucoma in patients who underwent silicone oil injection, as well as to evaluate the effectiveness of medical and surgical therapy in patients in whom glaucoma developed. METHODS: The postoperative courses of 50 eyes of 47 consecutive patients who underwent pars plana vitrectomy and silicone oil injection for the management of complicated retinal detachments were reviewed retrospectively. The outcomes of patients who underwent silicone oil removal and/or glaucoma surgery also were evaluated. RESULTS: The mean overall postoperative IOP before any glaucoma surgery was 16.7 +/- 9.3 mmHg (range, 0 to 45 mmHg), with a mean follow-up of 16.6 +/- 12.1 months (range, 2 to 51 months). Twenty-four (48%) eyes had postoperative IOPs of at least 25 mmHg and IOP elevations of at least 10 mmHg above the preoperative levels. Twenty-one (42%) eyes underwent complete removal of silicone oil and/or glaucoma surgery to effect IOP control. The IOPs were controlled to 21 mmHg or less (but > 5 mmHg) in 8 of 14 eyes that underwent removal of silicone oil alone, in 3 of 5 eyes that underwent Molteno implantation, and in 1 eye that underwent Nd:YAG transscleral cyclophotocoagulation, but not in 1 eye that underwent a modified Schocket procedure (mean follow-up, 13.5 +/- 11.0 months; range, 0.2 to 33 months). CONCLUSION: Intraocular pressure elevation is a common occurrence after intravitreal silicone oil injection. The underlying mechanism may often be multifactorial in nature. Patients in whom uncontrolled IOP develops may benefit from aggressive medical and/or surgical treatment with silicone oil removal, glaucoma implants, or cyclodestructive procedures.

Adolescent

Which is better? One or two? A randomized clinical trial of single-plate versus double-plate Molteno implantation for glaucomas in aphakia and pseudophakia.

PURPOSE: Previous studies have suggested that primary double-plate Molteno implantation may be beneficial. Therefore, the authors performed a randomized clinical trial to evaluate the relative effectiveness and safety of single- versus double-plate Molteno implantation. METHODS: From March 1988 to February 1990, 132 patients who underwent Molteno implantation for medically uncontrollable non-neovascular glaucomas in aphakia or pseudophakia were randomly assigned to receive either single- or double-plate implants. RESULTS: The 1- and 2-year life-table success rates (success [survival] defined as 6 mmHg < or = final intraocular pressure [IOP] < or = 21 mmHg without additional glaucoma surgery or devastating complication) were 55% and 46% with single-plate implantation and 86% and 71% with double-plate implantation, respectively. The final postoperative visual acuities were within one line of the preoperative visual acuities or had improved in 73% and 80% of patients, respectively. Choroidal hemorrhages and/or effusions, corneal decompensation, flat anterior chambers, and phthisis bulbi were more common in the patients who had undergone double-plate Molteno implantation; however, transient elevations of IOP during the first few postoperative months were more common in the patients who had undergone single-plate Molteno implantation. CONCLUSIONS: Double-plate Molteno implantation more frequently affords IOP control than single-plate Molteno implantation; however, double plates are associated with greater risks of choroidal hemorrhages and/or effusions, corneal decompensation, flat anterior chambers, and phthisis bulbi.

Adolescent

Clinical experience with the single-plate Molteno implant in complicated glaucomas. Update of a pilot study.

Ninety-six patients who had undergone single-plate Molteno implantation for glaucomas with poor surgical prognoses were re-evaluated for long-term results. Control of intraocular pressure was achieved with one single-plate implant to a level less than 22 mmHg (but greater than 5 mmHg) without reoperation or devastating complications in 46% of the aphakic/pseudophakic eyes, 25% of eyes after failed filters, 25% of eyes with neovascular glaucomas, and 26% of eyes in patients younger than 13 years of age (life-table analysis at 5 years). Five-year success rates improved to 53%, 71%, 40%, and 56%, respectively, when data from second plates were included. Visual acuities improved or remained the same after one or two plates were implanted in 47% of aphakic/pseudophakic eyes, 17% of eyes after failed filters, 65% of eyes with neovascular glaucomas, and 63% of eyes in patients younger than 13 years of age on whom Snellen acuity was available. The most frequent overall complications after implantation of one or two plates included: corneal edema (19%), corneal graft decompensation (13%), and cornea-tube touch, retinal detachment, and cataract (8% each).

Adolescent