10 Trocar Anterior Chamber Maintainer: An Improvised New Concept for Infusion and Endothelial Keratoplasty The merits of a closed chamber infusion system that helps to maintain the tonicity of the globe throughout intraocular surgery cannot be overstated. Maintenance of a deep anterior chamber (AC) is a prerequisite for safe, smooth performance of intraocular surgery because it prevents inadvertent and harmful touch to the corneal endothelium and also to various other structures. For the same reason sodium hyaluronate was introduced and it served as a major breakthrough for all anterior segment intraocular surgeries.1,2,3 Although the use of viscoelastic also plays an important role, its use for maintenance of an AC in corneal surgeries is not a prudent idea, more so with endothelial keratoplasty (EK) procedures. Blumenthal devised a simple and practical method for maintaining the AC with a device that he called the anterior chamber maintainer (ACM), which was made from a 21-gauge scalp vein (**butterfly**) set. Since the introduction of an ACM there have been various modifications to the ACM to suit the surgical condition of the eye. The ACM4,5,6 and trocar cannula are the most common methods employed for infusion by anterior segment and posterior segment surgeons, respectively. Introduction of the trocar cannula was a monumental advance in ophthalmology because it allowed, for the first time, controlled access to the posterior segment of the eye. It is also an integral part of modern pars plana vitrectomy for maintaining infusion in the eye.7,8,9,10,11 A 23-gauge (0.6 mm), 25-gauge (0.5 mm), or 27-gauge (0.4 mm) trocar system can be introduced transconjunctivally through the tenon’s layer to expose the sclera. Instead, trocars are placed through the conjunctiva and sclera to afford access to the vitreous and also to maintain infusion in the eye. We designed a trocar AC maintainer (TACM) to help surgeons achieve better infusion (► Fig. 10.1). The TACM can be used by anterior segment surgeons for air/fluid infusion into the eye.12 Fig. 10.1 Design of the trocar AC maintainer (TACM; Sterimedix). Taking into consideration the advantages of a trocar system, we employed a method of introducing the trocar cannula for AC maintenance that could be used by anterior segment surgeons with equal ease and élan. Initially we used normal trocars that were designed for posterior segment surgeries (► Fig. 10.2). Although we attained good infusion of air and fluid through it, we still felt the need for a trocar with a shorter blade so that any damage to the AC intraocular structures could be avoided (► Fig. 10.3). Before cannula insertion, the conjunctiva is displaced with a cotton tip to keep the conjunctival puncture away from the sclera–limbal wound. The cannula (on a trocar) is inserted into the limbus approximately 1 mm away, usually at a 45-degree angle (depending on the gauge) and parallel to the limbus. The trocar is then turned directly toward the center of the globe so that it enters the AC in front of the iris tissue. It is advanced until the hub of the cannula is flush with the sclera. The trocar is then removed, leaving the cannula in place. This maneuver allows a longer scleral wound and carries a lower risk of wound leakage. The infusion line is attached to the stent of the cannula, and the infusion is turned on. At the end of the surgical procedure, the surgeon just withdraws the TACM, and, because the wound is self-sealing, no leakage is observed (► Fig. 10.4). Fig. 10.2 A 23-gauge retinal trocar was used as the first trocar anterior chamber maintainer (TACM). (a) The 23-gauge trocar cannula system. (b) A trocar needle being inserted obliquely in the sclera about 1 mm away from the limbus. (c) The direction of the trocar needle is turned perpendicular toward the globe. The trocar is inserted in the eye so that it enters the eye in front of the iris. (d) The trocar is removed and the cannula is fixed in place. (e) The infusion line is attached to the cannula and the TACM is in place. (f) The cannula is removed and no active leakage is observed. The anterior chamber is well maintained.
10.1 Concept
10.2 Trocar Anterior Compartment Maintainer (TACM) Device
10.3 Procedure of Positioning TACM in AC
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