Tui H. Bevin

Otago Glaucoma Surgery Outcome Study ☆: factors controlling capsule fibrosis around Molteno implants with histopathological correlation

OBJECTIVE To describe the histopathology of Molteno implant capsules in cases of primary and secondary glaucoma and to correlate them with surgical technique and clinical outcomes in quiet eyes. DESIGN Human tissue study with clinicopathological correlation. MATERIALS Seventy-five autopsy eyes or surgical pathology specimens obtained between 4 days and 23 years after insertion of Molteno implants were studied. Basic histologic features common to all bleb capsules were described, and the thickness was measured in 28 specimens from quiet eyes. MAIN OUTCOME MEASURES Histologic features of capsules, including wall thickness, distribution of inflammatory cells, and presence or absence of fibrodegeneration, were assessed by light microscopy. RESULTS Without aqueous flow (first stage of 2-stage insertion), the episcleral plates of Molteno implants were encapsulated by a very thin (20-60 micro m) avascular collagenous layer. The second stage of 2-stage insertion, with delayed drainage of aqueous and early temporary postoperative intraocular pressure (IOP) increase to 25 to 35 mmHg, produced thin (190-250 micro m) permeable capsules with fewer fibrovascular than fibrodegenerative components. Insertion of nonligatured implants with immediate aqueous flow produced thicker capsules (300-600 micro m) composed of an outer fibrovascular layer and an inner fibrodegenerative layer of approximately equal thickness. Three-stage insertion of modified Molteno implants with temporary externalization of aqueous flow onto the conjunctival surface and postoperative IOP not exceeding 12 mmHg produced the thickest (375-700 micro m) heavily fibrosed and impermeable capsules composed entirely of dense fibrovascular tissue without a fibrodegenerative layer. CONCLUSIONS Capsules around functioning Molteno implants evolved through a series of histologic stages. Without aqueous flow, the episcleral plate of the implant stimulated encapsulation by a thin avascular collagenous layer. With aqueous flow, an immediate inflammatory reaction developed in the episcleral connective tissues that included collagenous and vascular components. After a variable delay, a fibrodegenerative process developed in the deeper layers of the capsule. The fibrodegenerative process may depend on sufficient increases of IOP for aqueous to displace interstitial tissue fluid from the deeper layers of the capsule. The final thickness and permeability of the capsule probably depend on the relative intensity and timing of these opposing processes, which were influenced by surgical technique and postoperative management.

Long term follow up of bone derived hydroxyapatite orbital implants

Aims: To document the long term experience of bone derived hydroxyapatite orbital implants and compare results using scleral wrapped implants with those not using sclera. Methods: This retrospective case series reviewed the long term follow up of 118 patients with 120 eyes which had undergone enucleation and bone derived hydroxyapatite orbital implant insertion at Dunedin Hospital from 1977 until 2000. Patient details were obtained from theatre records, case note review, patient interview and examination, interview of patient relatives, and family general practitioner records. Results: Of the 120 eyes 84 had bone derived hydroxyapatite orbital implants with sclera and 36 without sclera. Follow up was 0.5–25 years (mean 8.9 years). 25 (19.3%) suffered minor complications of limited exposure of the implant which resolved spontaneously, with implant drilling or wound resuture. Nine (7.5%) suffered major complications requiring explantation. Major complications were more likely in cases with major tissue disruption, ischaemia, or inflammation. There were significantly fewer complications in the group where a bone derived hydroxyapatite orbital implant was implanted without a scleral covering (p<0.05). Conclusions: The placement of a bone derived hydroxyapatite orbital implant in the socket was associated with a low rate of long term complications and good cosmesis in most cases. The omission of a scleral covering over the hydroxyapatite sphere had some advantages and may prove to be the procedure of choice.

Anti-inflammatory fibrosis suppression in threatened trabeculectomy bleb failure produces good long term control of intraocular pressure without risk of sight threatening complications

Aims: To determine the long term outcome of systemic anti-inflammatory fibrosis suppression in cases of threatened trabeculectomy bleb failure in open angle glaucoma. Methods: This prospective non-comparative case series followed 77 eyes of 63 patients which showed signs of threatened early bleb failure and were treated with oral anti-inflammatory fibrosis suppression of prednisone, a non-steroidal anti-inflammatory agent, and colchicine taken for a mean period of 6 weeks, in addition to standard postoperative topical treatment, for a mean follow up of 6 years. Results: Trabeculectomy with anti-inflammatory fibrosis suppression controlled the IOP at ≤21 mm Hg with a probability of 0.91 (95% CI: 0.81 to 1.0) at 8 years and 0.89 (95% CI: 0.56 to 1.1) at 12 years. There were no reported cases of endophthalmitis, hypotonous maculopathy, late bleb leak, or serious systemic side effects. Conclusion: Anti-inflammatory fibrosis suppression provided good control of bleb fibrosis without risk of sight threatening complications in a patient group at high risk of bleb failure.

Otago glaucoma surgery outcome study: long-term follow-up of cases of primary glaucoma with additional risk factors drained by Molteno implants.

OBJECTIVE This study was undertaken to provide data on the long-term results of cases of primary open-angle glaucoma with additional risk factors drained by Molteno implants in the province of Otago, New Zealand. DESIGN Prospective, noncomparative case series PARTICIPANTS One hundred thirty eyes of 103 patients drained by Molteno implants as the first surgery between 1984 and 1999. INTERVENTION Insertion of Molteno implant (Ethicon Inc., Johnson & Johnson, Somerville, NJ) using the Vicryl-tie technique. MAIN OUTCOME MEASURES Intraocular pressure (IOP), visual acuity, visual field. RESULTS Insertion of a Molteno implant controlled the IOP at 21 mmHg or less with a probability of 1.0 (95% confidence interval [CI], 0.90, 1.0) at up to 7 or more years after surgery. The mean preoperative visual acuity of 20/160 improved to 20/50 after operation and then declined to 20/55 at 5 years and 20/80 after 10 years. The probability of retaining useful vision (visual acuity, >20/400; visual field, >5 degrees radius) was 0.86 (95% CI, 0.77, 0.94) and 0.78 (95% CI, 0.67, 0.89) at 5 and 7 or more years, respectively, after surgery. CONCLUSIONS The insertion of Molteno implants using the Vicryl-tie technique in this series of 130 cases of primary open-angle glaucoma with additional risk factors controlled the IOP in all cases.

Systemic anti-inflammatory fibrosis suppression in threatened trabeculectomy failure.

Purpose: To provide a rationale for the use of systemic anti‐inflammatory fibrosis suppression in the postoperative management of threatened early trabeculectomy bleb failure.

Otago Glaucoma Surgery Outcome Study: long‐term results of 841 trabeculectomies

Background:  To describe the long‐term outcomes of trabeculectomies performed at Dunedin Hospital and followed in the Otago Glaucoma Surgery Outcome Study.

Otago Glaucoma Surgery Outcome Study: long term results of cataract extraction combined with Molteno implant insertion or trabeculectomy in primary glaucoma

Background/Aims: To describe the long term results of cases of cataract extraction combined with either Molteno implant insertion or trabeculectomy for primary open angle glaucoma. Methods: This prospective case series followed cases which had cataract extraction and Molteno implant insertion (45 eyes) or trabeculectomy (94 eyes) followed up for a mean of 5.3 years and 3.9 years respectively. Results: Cataract extraction and Molteno implant insertion or trabeculectomy controlled the intraocular pressure at 21 mmHg or less with a probability of 1.00 (95% CI 0.93 to 1.00) at 10 years or more after operation and 0.94 (95% CI 0.89 to 0.99) and 0.73 (95% CI 0.46 to 0.99) at five and 10 years after operation respectively. Conclusions: Cataract extraction combined with insertion of Molteno implants or trabeculectomy controlled the intraocular pressure in 100% (45/45) and 94% (88/94) of cases respectively.

Long-term follow-up of traumatic glaucoma treated with molteno implants

PURPOSE To determine the long-term outcomes of patients with traumatic glaucoma treated with Molteno implants at Dunedin Hospital, New Zealand. DESIGN Prospective, noncomparative, interventional case series. PARTICIPANTS Thirty-eight patients with traumatic glaucoma and with a mean follow-up of 10.9 years. INTERVENTION Insertion of Molteno implant. MAIN OUTCOME MEASURES Intraocular pressure (IOP) and intraocular pressure-related surgical interventions after Molteno implant insertion. RESULTS Insertion of a Molteno implant controlled the IOP at 21 mmHg or less (with or without hypotensive medication) with a probability of 0.80 (95% confidence interval [CI], 0.66, 0.93) at 5 years and 0.72 (95% CI, 0.56, 0.88) at 10 years. At final follow-up, intraocular pressure was controlled solely with the implant in 26 cases and controlled with the addition of hypotensive medication in three cases, whereas nine eyes were failures. Eleven patients (29%) underwent intervention for implant repositioning or tube orifice blockage. Thirty-four double- and six single-plate Molteno implants were inserted. Two patients had implants replaced. Seventy-nine percent became aphakic or pseudophakic from their trauma before or at the time of Molteno implant insertion. There were no exclusions resulting from extensive ocular damage. CONCLUSIONS Insertion of Molteno implants in traumatic glaucoma produced intraocular pressure control at long-term follow-up in 76% of cases.

Long-term Results of Primary Trabeculectomies and Molteno Implants for Primary Open-Angle Glaucoma

OBJECTIVE To describe the long-term outcomes of primary trabeculectomies and primary Molteno implants performed in cases of primary open-angle glaucoma at Dunedin Hospital. METHODS Prospective comparative case series of 718 eyes (500 patients) and 260 eyes (195 patients) that had trabeculectomy and Molteno implants, respectively, at Dunedin Hospital as the first drainage operation for primary open-angle glaucoma between 1976 and 2007, and followed up for a mean of 7.7 (range, 0.0-28.0) and 5.0 (range, 0.0-27.4) years, respectively. RESULTS The probability of intraocular pressure (IOP) control at 21 mm Hg or less following trabeculectomy at 1, 2, 5, 10, 15, and 20 years was 0.95 (95% confidence interval [CI], 0.94-0.97), 0.93 (95% CI, 0.91-0.96), 0.89 (95% CI, 0.86-0.92), 0.82 (95% CI, 0.78-0.86), 0.74 (95% CI, 0.68-0.80), and 0.68 (95% CI, 0.59-0.77), respectively. There were 96 (13%) failures (using the >21-mm Hg definition of failure) in the trabeculectomy group by the final follow-up. The probability of IOP control at 21 mm Hg or less following Molteno implant insertion at 1, 2, 5, 10, 15, and 20 years was 0.98 (95% CI, 0.97-1.0), 0.97 (95% CI, 0.96-1.0), 0.96 (95% CI, 0.92-0.99), 0.96 (95% CI, 0.92-0.99), 0.91 (95% CI, 0.81-1.00), and 0.91 (95% CI, 0.81-1.00), respectively. In the Molteno implant group, there were 8 (3%) failures (using the >21-mm Hg definition of failure) by the final follow-up. CONCLUSION Insertion of a Molteno implant provided superior IOP control to trabeculectomy when carried out as a first operation in cases of primary glaucoma.

Otago glaucoma surgery outcome study: tissue matrix breakdown by apoptotic cells in capsules surrounding molteno implants.

PURPOSE To identify cell types and extracellular matrix components in Molteno implant capsules. METHODS Histologic features including cytology, distribution of apoptotic cells, cytoantigens, collagens, basement membranes, elastic fibers, and glycoproteins were examined by light microscopy. Findings were correlated with the clinical features of 19 ocular specimens with glaucoma that had been treated with Molteno implants 11 days to 20 years previously. RESULTS All but the earliest specimen capsules showed two layers: a moderately cellular outer layer of normally stained collagen and an inner avascular hypocellular layer of altered collagen. Capsules contained metabolically active fibroblasts and macrophages showing swelling, vacuolation, and apoptosis with localized loss of extracellular matrix in the inner layers of older capsules. Type I collagen was present in trace amounts. Collagens types III and VI and fibronectin were present in high concentrations in the capsules. Basement membrane material (collagen type IV and laminin) and thrombospondin were concentrated in the inner avascular layers. CONCLUSIONS These results support previous findings that the normal capsule life cycle includes continual inner surface degeneration and external surface renewal. The cells and tissue matrix components of the outer capsule layer matched those involved in the initial phase of wound healing in vascular connective tissue. The tissue matrix components and widespread apoptosis found in the inner fibrodegenerative layer reflect scar tissue remodelling induced by exposure to the aqueous.