Terrell Jesse A, Blake Charles Richard
Ophthalmology, Baylor College of Medicine, Houston, USA.
Ophthalmology, University of Florida, Gainesville, USA.
Cureus. 2021 Sep 6;13(9):e17771. doi: 10.7759/cureus.17771. eCollection 2021 Sep.
Purpose Variation among aqueous humor outflow from venting slits performed on glaucoma drainage device tubing often occurs even when physician technique and equipment are held constant. Our hypothesis is that there are dimensional differences within the tubing, even among the same make and model of glaucoma drainage device (GDD) implants. Methods Prior to surgical implantation, excess glaucoma drainage tubing was collected for analysis. The tubing samples were sliced horizontally, and the external tube, internal lumen, and wall dimension measurements were collected microscopically. Groups were divided based upon brand and model and then statistically analyzed using an independent t-test. A total of 28 tubes were analyzed, consisting of 7 Molteno and 21 Baerveldt implants. Results The mean external diameter for the Molteno group was 656 ± 20µm, significantly larger than the Baerveldt external diameter of 620 ± 13µm (P<0.05). The mean internal diameter among Molteno lumens was 344 ± 13µm, also statistically larger than the mean internal diameter of 309 ± 18µm for Baerveldt tubes (P<0.05). The Molteno luminal wall width varied significantly less than the Baerveldt wall, 18% versus 28%, respectively (P<0.05). The tubings' wall widths variation translated into highly significant off-centered lumens among both brands. Conclusion Our findings suggest that there are significant variations among glaucoma implant dimensions between and within the multiple makes and models. The discrepancies among tubal wall thickness and off-centered lumens are undetectable to the naked eye. Importantly, this may result in significant aqueous humor outflow variation following the creation of venting slits secondary to the found irregular luminal diameters and tube wall thicknesses.
目的 即使医生技术和设备保持不变，青光眼引流装置管道上的引流切口处房水流出量仍常常出现差异。我们的假设是，即使在同一品牌和型号的青光眼引流装置（GDD）植入物中，管道内部尺寸也存在差异。方法 在手术植入前，收集多余的青光眼引流管道进行分析。将管道样本水平切片，通过显微镜收集外部管道、内部管腔和管壁尺寸测量数据。根据品牌和型号进行分组，然后使用独立t检验进行统计分析。共分析了28根管道，其中包括7根莫尔滕诺（Molteno）植入物和21根贝尔维尔德（Baerveldt）植入物。结果 莫尔滕诺组的平均外径为656±20µm，显著大于贝尔维尔德组的620±13µm（P<0.05）。莫尔滕诺管腔的平均内径为344±13µm，在统计学上也大于贝尔维尔德管的平均内径309±18µm（P<0.05）。莫尔滕诺管腔壁宽度的变化明显小于贝尔维尔德管，分别为18%和28%（P<0.05）。两种品牌管道的管壁宽度变化导致管腔高度偏心。结论 我们的研究结果表明，多种品牌和型号的青光眼植入物之间以及内部存在显著尺寸差异。管壁厚度和偏心管腔之间的差异肉眼无法察觉。重要的是，由于发现的管腔直径和管壁厚度不规则，这可能导致引流切口形成后房水流出量出现显著差异。
