Richard M H Lee1,2, Yann Bouremel2, Ian Eames3, Steve Brocchini2,4, Peng Tee Khaw2. 1. Department of Ophthalmology, Chelsea and Westminster Hospital NHS Foundation Trust. 2. NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology. 3. UCL Department of Mechanical Engineering. 4. UCL School of Pharmacy, London, UK.
Abstract
PURPOSE: The aim of this study was to present a case of a Baerveldt glaucoma implant lumen being completely occluded with a 3-0 Supramid stent suture. PATIENT AND METHODS: The patient underwent Baerveldt glaucoma implant surgery with placement of an intraluminal 3-0 Supramid stent suture that acts to restrict flow across the device and reduce the risk of postoperative hypotony. Following suturing of the implant to the sclera, the device was flow tested. No flow was observed through the device tube and a significant ballooning of the tube diameter occurred with increased pressure on the device. The device was explanted from the eye and replaced with a different implant without further postoperative complication. The explanted device was assessed using custom microfluidic equipment in an in vitro environment. RESULTS: This phenomenon occurred despite using several different batches of the 3-0 Supramid stent suture and the device had to be removed and replaced with another device without complication. In vitro microfluidic assessment of the device demonstrated no flow across the device tube despite over 150 mm Hg of pressure being exerted on the device. CONCLUSIONS: We hypothesize that the blockage occurred at the junction between the device tube and plate and that the ballooning phenomenon observed was due to a defect in the tube wall. This case highlights the importance of flow testing all glaucoma drainage devices before insertion given the variation in manufacturing conditions to avoid the risk of intraoperative complications.
PURPOSE: The aim of this study was to present a case of a Baerveldt glaucoma implant lumen being completely occluded with a 3-0 Supramid stent suture. PATIENT AND METHODS: The patient underwent Baerveldt glaucoma implant surgery with placement of an intraluminal 3-0 Supramid stent suture that acts to restrict flow across the device and reduce the risk of postoperative hypotony. Following suturing of the implant to the sclera, the device was flow tested. No flow was observed through the device tube and a significant ballooning of the tube diameter occurred with increased pressure on the device. The device was explanted from the eye and replaced with a different implant without further postoperative complication. The explanted device was assessed using custom microfluidic equipment in an in vitro environment. RESULTS: This phenomenon occurred despite using several different batches of the 3-0 Supramid stent suture and the device had to be removed and replaced with another device without complication. In vitro microfluidic assessment of the device demonstrated no flow across the device tube despite over 150 mm Hg of pressure being exerted on the device. CONCLUSIONS: We hypothesize that the blockage occurred at the junction between the device tube and plate and that the ballooning phenomenon observed was due to a defect in the tube wall. This case highlights the importance of flow testing all glaucoma drainage devices before insertion given the variation in manufacturing conditions to avoid the risk of intraoperative complications.