Modified Trabeculectomy Using Ologen® Collagen Matrix with or without A Cyclodestructive Procedure for Canine Glaucoma: A Retrospective Review of 14 Cases Sung-Jun Lee1 Joon-Young Kim2,† Soon-wuk Jeong1 1Department of Veterinary Surgery, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, Korea 2Veterinary Medical Teaching Hospital, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, Korea †Corresponding author: Joon-Young Kim Veterinary Medical Teaching Hospital, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, Republic of Korea Tel.: 82-2-444-6150 Fax: 82-2-444-4396 E-mail: [email protected] KEY WORDS: canine glaucoma, photocoagulation (TSCP); and group 3 (four cyclodestructive procedure, filtering eyes), MTO with endocyclophotocoagula- surgery, intraocular pressure, ologen® CM, tion (ECP). Data pertaining to signalment, trabeculectomy pre- and postoperative intraocular pressure ABSTRACT (IOP) and visual acuity, preoperative man- agement, detailed surgical procedures, post- Trabeculectomy in the dogs has not gener- ally used because of filtering bleb failure operative treatments, follow-up duration, due to episcleral fibrosis and subconjuncti- surgical outcomes, and complications were val scarring for glaucoma. To overcome this retrospectively reviewed. The outcomes of filtering bleb failure, we applied a modified trabeculectomy and bleb formation were trabeculectomy using ologen® Collagen evaluated using ultrasound biomicroscopy Matrix (CM) with or without a cyclode- (UBM). IOP was successfully stabilized at structive procedure for dogs with medically < 25 mmHg at different time points in 12 uncontrolled glaucoma. This study was of the 14 (85.7%) eyes. Six of nine eyes performed as retrospective case series. 14 (66.7%) maintained vision after surgery, and eyes of 12 dogs with medically uncontrolled two of five (40.0%) eyes with preoperative glaucoma was evaluated from 2015 through vision loss regained vision after surgery. All 2016. The dogs were divided into three eyes except two exhibited successful filter- groups: group 1 (six eyes), modified trabecu- ing bleb formation without major complica- lectomy using ologen® CM (MTO); group 2 tions. IOP showed no significant differences (four eyes), MTO with transscleral cyclo- among groups (P > 0.05). Modified trabecu- Intern J Appl Res Vet Med • Vol. 17, No. 2, 2019. 47 lectomy using ologen® CM is easy to per- of bleb-related complications such as bleb form and demonstrates successful outcomes leakage, subconjunctival tissue necrosis, with minimal postoperative complications. hypotony maculopathy, blebitis, and endo- This new surgical technique may be an ef- phthalmitis.2,7 Recently, tissue-engineered fective alternative procedure for IOP control implants were developed as alternatives to in canine glaucoma. MMC and 5-FU, with lesser adverse effects. One of these is the ologen® Collagen Matrix INTRODUCTION (ologen® CM, Aeon, Astron, Leiden, the Glaucoma is one of the common causes of 1, 2 Netherlands), which consists of lyophilized vision loss in humans and animals. Cur- porcine atelocollagen and glycosaminogly- rently, transscleral cyclophotocoagulation can with a 10- to 300-μm pore size. It is (TSCP), and endocyclophotocoagulation biodegradable and an implantable extra- (ECP) and are considered effective methods 3,4 cellular matrix (ECM) mimic specifically for lowering IOP in animals. But ECP is configured to support and modulate tissue generally performed at the time of phaco- repair processes in connective and epithelial emulsification with intraocular lens implan- ocular tissues.14 According to recently re- tation to prevent postoperative secondary 5 ported studies on glaucoma filtering surger- cataract formation. And TSCP can cause ies performed in animal models and humans, short- and long-term complications, such ologen® CM is effective in promoting bleb as postoperative intraocular hypertension, formation by modulating fibroblast migra- hyphema, uveitis, secondary cataract, and 4 tion and proliferation into the pore struc- ulcerative keratitis. In the field of veterinary tures and normalizing secreted collagen ophthalmology, the most common filter- and another extracellular matrix deposition, ing procedures involve the use of anterior 15,16 6 resulting in reduced scar formation. In chamber shunts or gonioimplantation. the present study, we aimed to determine Several reports have described gonioimplan- a surgical technique that is easier and less tation as an effective procedure for normal- complicated than gonioimplantation, which izing IOP and maintaining vision in dogs 2,7,8,9 is the most commonly used method, and in with medically uncontrolled glaucoma. our opinion, the use of ologen® CM for tra- However, it is associated with early and late beculectomy may be an effective alternative complications, including hypotony, ante- for the surgical treatment of canine glau- rior uveitis, tube obstruction, conjunctival coma. Although, to the best of our knowl- erosion, tube migration, corneal endothelial edge, no previous study has documented the decompensation, and filtering bleb failure, in 6,10 outcomes of modified trabeculectomy using humans and dogs. Trabeculectomy which ologen® CM with or without a cyclode- is another filtering surgery has not generally structive procedure for the treatment of used because of filtering bleb failure due canine glaucoma. The aim of the present to episcleral fibrosis and subconjunctival 4,6 study was to describe the surgical techniques scarring for glaucoma in the dogs. Exces- and clinical outcomes associated with modi- sive fibrosis of the filtering bleb may lead fied trabeculectomy using ologen® CM with to bleb failure and lower the success rate of or without a cyclodestructive procedure for filtering surgeries, including trabeculectomy medically uncontrolled glaucoma in 12 dogs and gonioimplantation, in both humans and (14 eyes). animals.11,12 To prevent bleb scarring, several adjunctive antimetabolies, including mito- MATERIALS AND METHODS mycin C (MMC) and 5-fluorouracil (5-FU), Review of medical records are commonly used.2,11,13 Although the use of The medical records at Veterinary Medi- antimetabolites during or following surgery cal Teaching Hospital (VMTH), Konkuk has improved the long-term success rate for University were reviewed to identify 14 filtering surgeries,2,8 it has increased the rate eyes of 12 dogs with medically uncontrolled Intern J Appl Res Vet Med • Vol. 17, No. 2, 2019. 48 Figure 1. Modified trabeculectomy with ologen® glaucoma treated by modified Collagen Matrix (CM) for medically uncontrolled trabeculectomy using ologen® CM glaucoma in dogs. (a) A fornix-based conjunctival/ with or without a cyclodestructive Tenon’s flap is prepared at the 12 o’clock position, 0.5 procedure (TSCP or ECP) from mm behind the superior limbus. (b) A rectangular 2.0 x 2015 through 2016. Data pertain- 2.0-mm2 wide, 300-μm thick limbal-based scleral flap ing to signalment, pre- and post- is dissected using a crescent knife. operative IOP and visual acuity, (c) A 1 to 1.5-mm trabeculectomy window is created preoperative management, detailed using a corneoscleral punch for glaucoma after the surgical procedures, postoperative placement of a stab incision using a No. 11 blade. (d) treatment, follow-up duration, sur- The scleral flap is repositioned with ologen® CM (8.0 gical outcomes, and postoperative × 2.0 × 2.0 mm) implanted beneath it. (e) Flap closure complications were collected. The is achieved with two interrupted sutures, one tight and outcomes of trabeculectomy and one loose, using 10-0 nylon on the bilateral edges of bleb formation were also evaluated the flap. (f) Another ologen® CM (10.0 × 8.0 × 2.0 using ultrasound biomicroscopy mm) implant is positioned over the scleral flap without (UBM). All eyes were divided the use of sutures. (g) The conjunctiva is closed with a into three groups according to the simple continuous suture pattern using 9-0 polyglactin surgical procedure. Six eyes (cases 910. 1–6, group 1) underwent modified trabeculectomy using ologen® CM (MTO), four eyes (cases 7–10, group 2) underwent MTO with TSCP, and four eyes (cases 11–14, group 3) underwent MTO with ECP. Pre- and postoperative IOP was evaluated using applanta- tion tonometry (Tonopen VetTM, Reichert. INC., Depew, NY, USA). All data were statistically analyzed using SPSS statistics 24.0 for Win- dows (IBM, Armonk, NY, USA). The normality of data distribution was evaluated using the Shapiro– Wilk test. One-way ANOVA and the Kruskal–Wallis test were per- formed to compare differences in mean IOP values at different time points (before surgery; 5 h, 1 day, and 1, 2, 3, 4, 5, 6, and 12 months after surgery) among the three groups. A P-value of <0.05 was considered statistically significant. Modified trabeculectomy using ologen® CM General anesthesia was induced with intravenous propofol (6 mg/ kg; Provive 1%, Myungmoon Pharm. Co., Ltd, Korea) and main- tained with 1.5%–2.0 % isoflurane Intern J Appl Res Vet Med • Vol. 17, No. 2, 2019. 49 TableSummary 1. of signalment and clinical data of surgical procedures performed in each case. Case Breed Age Cause of Pre-OP Surgery Pre-OP Post-OP Post-OP Follow-up Maintenance of IOP below 20 Complications No. glaucoma IOP visual status visual status visual status duration (weeks) mmHg during the follow-up period 1 ACS 3 Cataract 41 MTO Vision Vision 52 52 ○ None surgery maintained maintained 2 ECS 12 PACG 35 MTO Blind Vision 26 26 ○ None maintained