Fig. 5.21 During injection of gas through the infusion line, you need to decompress the globe by holding the fluid needle in a trocar cannula to relieve pressure

Pits & Pearls

Most vitreoretinal surgeons use 20% SF6 as tamponade for macular hole. However, some surgeons prefer 15% C2F6, 14% C3F8 or even 1,000-cSt silicone oil. Silicone oil or heavy silicone oils are also a good choice for patients who are unable to position themselves in the prone position.

7. Removal of the trocars

The sclerotomies need not be sutured. Exception: open connection from sclerotomy and conjunctiva with potential vitreous wicking with a risk for endophthalmitis. The big advantage of not suturing is that a postoperative hypertension due to the expanding gas, though rare, allows the gas to escape through the unsutured sclerotomies.

5.425-Gauge Macular Peeling

DVD

Video 7c 25-gauge macular peeling

Macular peeling in 25-gauge has the advantage of less trauma to the conjunctiva and an improved sclerotomy closure related to to this type of surgery (Fig. 5.22). In 23-gauge, you sometimes need a suture for the sclerotomy; in 25-gauge, you almost never need a suture.

Most companies offer 23-gauge and 25-gauge custom packs including trocars, vitreous cutter and light pipe. In addition, you have to purchase two products: (1) A 25-gauge infusion needle (DORC) for the fluid needle and the syringe with the dye.

(2) 25-gauge Eckardt forceps (DORC and Geuder). The neurotomy knife is only available in 25-gauge.

Fig. 5.24 Injection of gas: Remove one or two instrument trocars. Inject the gas through the infusion line. The remaining air escapes through the open trocar and/or the sclerotomies. At last remove the infusion line with infusion trocar

Fluid needle: The fluid needle cannula comes with a soft tip (Fig. 5.23a, b). We remove the plastic tip of the infusion cannula with a needle holder in order to achieve an easier insertion into the trocars. We further recommend the use of the fluid needle with active aspiration because a passive fluid–air exchange with 25-gauge is really slow.

Insertion of trocars: Insert the 25-gauge trocars in a lamellar fashion as in 23-gauge. Gas tamponade: Remove one or both instrument trocars before injecting the gas (Fig. 5.24).

Reference

Romano MR, Groenwald C, Das R, Stappler T, Wong D, Heimann H (2009) Removal of Densiron-68 with a 23-gauge transconjunctival vitrectomy system. Eye (Lond) 23(3):715–717

Bimanual vitrectomy is an essential part of modern Minimal Incision Vitreoretinal Surgery (MIVS). By inserting a stationary chandelier light in the sclera (4-port vitrectomy, Fig. 6.1), the surgeon has two active hands. To operate with two active hands is a new and exciting method of surgery. For example, in retinal detachment surgery, one can indent the sclera with one hand and vitrectomize the vitreous base with the other hand. In diabetic retinopathy, one can apply laser photocoagulation up to the ora serrata with the help of a scleral depressor. One can remove membranes with two different instruments and also apply counteraction.

For optimal use of a chandelier light, three requirements have to be met:

1. Inferonasal insertion enabling a good rotation of the globe

2. A rigid cable allowing aiming the light source in all directions in the vitreous cavity

3. External light source for optimal illumination

Fig. 6.1 An eye with 4-port vitrectomy. In addition to the known 3-port system, a chandelier light fibre was firmly inserted into the sclera (top left)