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R. S. Hoffman |
surgeon, irrigation can be accomplished with the bimanual irrigation handpiece that can also function as the second “side-port” instrument negating the need for an irrigating chopper.
The greatest criticism of biaxial phaco lies in the fluidics and the current limitations in intraocular lens technology that could be utilized through these microincisions in the US. Because of the size of these incisions, less fluid flows into the eye than what occurs in coaxial techniques. Most, current irrigating choppers integrate a 20-gauge lumen that limits fluid inflow. This can result in significant chamber instability when high vacuum levels are utilized and occlusion from nuclear material at the phaco tip is cleared. Thus, infusion needs to be maximized by placing the infusion bottle on a separate IV pole that is set as high as possible. Also, vacuum levels usually need to be lowered below 350 mmHg to avoid significant surge flow, although newer phacoemulsification machines continue to improve the ability to raise vacuum and maintain a stable anterior chamber.
6.8.4 Final Thoughts
Ultimately, the surgeons and the marketplace forces will dictate how cataract surgical technique will evolve. The hazards and the prolonged recovery time of large incision intraand extracapsular surgery eventually spurred the acceptance of phacoemulsification, despite the difficult learning curve. Surgeons comfortable with their extracapsular skills disparaged phaco until the advantages were too powerful to ignore. Similar inertia has been evident in transitioning to foldable IOLs, clear corneal incisions, and topical anesthesia and the use of these practices is increasing every year. The future lens procedure of choice will eventually be decided by its potential advantages over traditional methods and by the collaboration of surgeons and industry to deliver a safe and effective technology. Biaxial microincision phacoemulsification is the next step in the evolution of phacoemulsification.
Take Home Pearls
ßThe capsulorhexis can be started using the sharp tip of a single blade of the rhexis forceps
in the open position and then completed by grasping the edge of the rhexis in a standard fashion.
ßIt should be ensured that the leading tip of the chopping element is past the internal incision
opening prior to rotating the chopper handpiece and inserting the remainder of the irrigating chopper.
ßCortical cleaving hydrodissection should be performed and the lens should be rotated prior
to performing hydrodelineation. This will insure that both the endonucleus and the epinucleus are freely mobile. Free mobility of both the epinucleus and the endonucleus will greatly facilitate lens removal with a biaxial method.
ßThe vertical chopping element of the chopper should be rotated counter-clockwise into a
horizontal position when aspirating the epinucleus, to lessen the likelihood of tearing the posterior capsule with the chopper.
ßBiaxial I&A facilitates cortex removal by allowing easy access to 360° of the capsular
fornices. This lessens the chances for capsule tearing during the removal of subincisional cortex.
References
1. Agarwal A, Agarwal A, Agarwal S et al (2001) Phakonit: phacoemulsification through a 0.9 mm corneal incision. J Cataract Refract Surg 27:1548–1552
2.Shock JP (1972) Removal of cataracts with ultrasonic fragmentation and continuous irrigation. Trans Pac Coast Otoophthalmol Soc Annu Meet 53:139–144
3.Girard LJ (1978) Ultrasonic fragmentation for cataract extraction and cataract complications. Adv Ophthalmol 37:127–135
4.Fine IH (1998) The choo-choo chop and flip phacoemulsification technique. In: Elander R (ed) Operative techniques in cataract and refractive surgery. W.B. Saunders, Philadelphia, PA, pp 61–65
5.Fine IH, Packer M, Hoffman RS (2001) The use of power modulations in phacoemulsification: choo choo chop and flip phacoemulsification. J Cataract Refract Surg 27: 188–197
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6.Masket S, Tennen DG (1996) Astigmatic stabilization of 3.0 mm temporal clear corneal cataract incisions. J Cataract Refract Surg 22:1451–1455
7.Shearing SP, Relyea RL, Loaiza A, Shearing RL (1985) Routine phacoemulsification through a one-millimeter nonsutured incision. Cataract 2:6–10
8.Tsuneoka H, Shiba T, Takahashi Y (2001) Feasibility of ultrasound cataract surgery with a 1.4 mm incision. J Cataract Refract Surg 27:934–940
9.Tsuneoka H, Shiba T, Takahashi Y (2002) Ultrasonic pha-
coemulsification using a 1.4 mm incision: clinical results. J Cataract Refract Surg 28:81–86
6.9BiMICS vs. CoMICS: Our Actual Technique (Bimanual Micro Cataract Surgery vs. Coaxial Micro Cataract Surgery)
Jerome Bovet
Core Messages
ßReduction of the incision size is one of the goals of microincision cataract surgery in order
to avoid induced astigmatism.
ßA balance between irrigation and aspiration is the key element to avoid complications in pha-
coemulsification by microincision.
ßThe inflow of the fluid inside the anterior chamber is as important as the outflow.
6.9.1 Introduction
Bimanual and coaxial microincision cataract surgery are not two conflicting surgical techniques, but rather, they are the products of a common goal to control better, and reduce induced astigmatism during cataract surgery [12] (Fig. 6.71). The 3 mm incision has already become obsolete, just as that of the 12 mm and subsequently, the 6 mm incisions [4, 14]. The decrease in the size of cataract incisions will reduce, if not eliminate, induced astigmatism, thus bringing the surgery under better control of the surgeon [9]. Likewise, it opens the door to refractive lens surgery (as an application of bioptics to cataract surgery), combining both phacoemulsification and intraocular lens (IOL) implantation with LASIK during presby surgery.
J. Bovet
clinique de l’oeil, 15 bois de la chapelle, 1213 Onex, Geneva, Switzerland
e-mail: jbovet@vision.tv