a

b

Fig. 5.8 (a) “Infusion spatula”: When nuclear division is completed, the tip of a high-flow infusion handle is inserted to boost irrigation. It also serves as a blunt spatula to manipulate the nuclear pieces towards the tip opening, and is positioned between the posterior capsule and tip when occlusion break is imminent in order to mechanically protect the posterior capsule should chamber flattening occur. (b) Prototype of infusion spatula with oval cross-section and low-resistance shaft for maximum through-put of infusion fluid (Geuder, Germany)

along. The internal step from tip head to shaft significantly enhances the efficiency of the phaco tip and avoids tip obstruction (“clogging”) by nuclear pieces. To be efficient, this requires adaptations in the phaco technique. With strongly bevelled tips, direct nuclear cracking has turned out to be the most appropriate technique. For both the divide and conquer manoeuvres, the bevel is turned sideward. An additional infusion handle inserted through the side-port allows for very high vacuum and flow settings and saves phaco time and energy. This provides for both maximum efficiency and safety of phacoemulsification procedure.

5.1.2.4The OS3 and CataRhex SwissTech Platforms

The Oertli OS3 and Oertli CataRhex SwissTech platforms (Fig. 5.9) support both coaxial and bimanual MICS. While (sleeveless) bimanual MICS requires adjustments of fluidics and “cool phaco” power settings, which are readily available on these platforms by simply pressing the CMP cool micro pulse button, coaxial MICS with the Oertli CO-MICS tip needs an increase of the vacuum only.

However, in our experience the coaxial approach to MICS has two major advantages: (1) The sleeve seals the wound, thereby preventing fluid outflow. With sleeveless phaco tips, fluid loss is not only inevitable but also variable depending upon the relative orientation of the tip with regard to the wound. This leads to pressure fluctuations within the chamber which may be difficult to counterbalance and carry the risk of a chamber collapse in case of occlusion break. (2) The sleeve protects the surrounding wound tissue from mechanical and thermal damage [1, 2]. With sleeveless phaco tips, the wound slit must be kept as narrow as possible to provide a tight fit and thus avoid excessive fluid outflow. This may lead to tissue damage especially when instrument manipulation in a tight incision causes oar locking of the wound. Other advantages of coaxial MICS are improved fluidics as dealt with in Sect. 3.2 in Chap. 3 “How to better use fluidics in MICS”. Use of OS3 and CataRhex SwissTech platforms is therefore described for coaxial MICS only.

Equipment

No specific software or special tubing-system or other modification is required to do coaxial MICS with the OS3 and CataRhex SwissTech platforms. The CO-MICS 2 (Oertli) phaco tip and sleeve are mounted to the Oertli Hexadisq phaco hand piece. The front side of the sleeve must be positioned as illustrated in Fig. 5.10.

When appropriately adjusted, the front of the sleeve seals with the backside of the tip head, avoiding anteriorly directed inflow. With traditional tips, this coaxial inflow tends to push fragments away from the tip. With the CO-MICS 2 tip, the irrigation fluid inflow is essentially confined to the side openings.

Machine Settings

CO-MICS 2 works equally well with the venturi or the peristaltic pump of the OS3 platform. A venturi surgeon can stay with the venturi pump, a peristaltic surgeon with the peristaltic pump. In both cases the vacuum limit alone needs to be changed. Here are the rules of thumb:

Do not be afraid of working with high vacuum levels. CO-MICS 2 provides for excellent chamber stability and suppresses surges. The behaviour is very different from standard 2.8 mm incision tips, and is much smoother and more “forgiving”.

The CO-MICS 2 tip provides for astonishing phacoemulsification efficiency and chamber stability, inherent reduction of surge upon occlusion break and optimally preserves the integrity and self-sealing properties of the wound.

Take Home Pearls

ßWith up-to-date cataract equipment, it is possible to perform safe and efficient coaxial pha-

coemulsification through a 1.4 mm incision.

ßThe optimization of the small-incision phaco tip is based on physical principles of fluidics

and ultrasonics.

ßThe only change in the machine settings is the vacuum limit: the vacuum limit has to be raised

by approximately 150 mmHg in order to get the same quality and efficiency as with 19-gauge surgery.

ßCorneal micro-incisions must have a funnelshaped configuration.

ßSleeve-armed CO-MICS-style microtips perfectly protect and seal the incision while pro-

viding optimum fluidics and power efficiency.

ßStrongly bevelled micro-tips require an adapted divide-and-conquer technique.

ßThe additional use of an irrigation spatula (“hybrid phaco”) allows to safely perform high-

flow high-vacuum phaco and thus dramatically reduces phaco power consumption.

4.Ernest PH, Lavery KT, Kiessling LA. Relative strength of scleral corneal and clear corneal incisions constructed in cadaver eyes. J Cataract Refract Surg 1994; 20:626–629

5.Oki K. Normal tension cataract surgery. In: Video 20th Congress of the German Ophthalmic Surgeons, Nuremberg, 2007

6.Menapace R. Technique of “infusion-assisted coaxial microphacoemulsifaction”. J Cataract Refract Surg

7.Menapace R. Time, energy and fluid consumption with “infu- sion-assisted coaxial microphacoemulsifaction”. J Cataract Refract Surg