Closing the Wound: an Eye-Opening Mechanism

Abstract

Background: Treatment of eye conditions, such as retinal detachment, macular pucker or macular holes, ask for an intervention named ”vitrectomy”. In a vitrectomy, multiple surgical instruments are brought into the eye, to facilitate removal of the vitreous humor. The instruments enter the eye through trocar ports that are placed in the sclera. Post operation, this passageway is removed, leaving an incision wound in the sclera. These wounds that remain after removal may cause complications such as hypotony and endophthalmitis. Current studies suggest that the frequency of these complications decreases when the incision architecture (i.e., the number of incision planes that are used to construct the
wound) , made during insertion of the trocar port, has better self sealing properties. The objective for this study is to develop and verify a surgical instrument that can consistently create the most effective self-sealing scleral incisions.
Method: An analysis is performed that investigates the relation between the incision architectures and the corresponding self-sealing characteristics. This analysis is done through information found in literature and an experiment. In this experiment, incisions with a variety of incision architectures are made in a setup that imitates the characteristics of the
human eye. Based on the analysis, incisions with a bi-planar architecture hold the greatest potential for consistent self-sealing incisions. A set of requirements are formulated that are used to generate a functional prototype that is capable of creating bi-planar incision. This concept consist of a high precision pin and slot mechanism linked to an actuation handle.
Verification of the established requirements and evaluation of the prototype performance are achieved by incisions in silicone slabs (i.e., eye phantoms).
Results: The defined Bi-planar architecture is set to have an oblique plane of 0.500 mm, a vertical plane of 0.250 mm and the angle between the two planes of 60.0◦. The Bi-Planar Incision Mechanism showed to have an mean oblique plane of 0.530 mm (SD = 0.043), a mean vertical plane of 0.248 mm (SD = 0.0286) and a mean angle of 60.08◦ (SD = 2.40).
The incision were performed with an average time to completion of 5.0 seconds (SD = 1.5).
Conclusion Using the Bi-Planar Incision Mechanism showed to be a successful method to make the desired bi-planar incisions. The result showed precise, accurate and fast incisions. The next step is to validate the self-sealing statistics in conditions that resemble those found in the operation room.