scissors (Fig. 10.8), diamond-dusted membrane brush, extrusion tips (Fig. 10.9), and laser probes. These are listed in Table 10.1.

When cannulae are used, the potential is present for a greater flow of infusion fluid during the case, especially when pressurized infusion flow is used to maintain the intraocular pressure during surgery. Cannulae with silicone-covered openings have been developed that reduce the fluid flow when instruments are removed from the eye (Fig. 10.10). While these cannulae reduce fluid flow, sometimes they can be cumbersome when curved or silicone-tipped instruments must be inserted.

Small-incision vitreoretinal surgery may occasionally be enhanced by the addition of a fourth incision. The use of additional light fibers may be inserted

through the pars plana [52, 53]. This light fiber is inserted after a needle is inserted transconjunctivally to provide an opening, usually at the 6:00 position 3.5 mm posterior to the corneal limbus. The tip of the fiber is tapered and rounded to provide wide angle or panoramic illumination so that the surgeon has the ability to operate bimanually (Fig. 10.11).

10.2.4 Common Surgical Techniques

Selected techniques incorporating minimally invasive instrumentation are described for commonly operated vitreoretinal disorders [54–57]. The authors’ personal

Fig. 10.11 Twin 27-gauge lights can be used for chandelier light. The one shown here was developed by Claus Eckhardt

preferences are for the use of 23-gauge technology, and therefore most of the techniques illustrated will exhibit this size but are applicable to 25 gauge.

10.2.4.1 Macular Surgery

Macular disorders such as macular holes, macular pucker [Video 3], and vitreofoveal traction are excellent types of cases for small-incision vitrectomy [21, 58–65]. Since progression of nuclear cataract is a common development after macular surgery, the feasibility of combined phacoemulsification and intraocular lens (IOL) implantation with vitrectomy and membrane peeling [66, 67] is excellent and reduces the rehabilitation time for the patient. The use of small-incision approach reduces the postoperative recovery time and the amount of postoperative medications necessary for healing, allowing the patient to resume normal activity more quickly [68]. After central vitrectomy, if the posterior hyaloid is not separated, triamcinolone suspension (10 mg/mL) is injected into the vitreous cavity. After separating the posterior hyaloid, another intraoperative triamcinolone injection is sometimes used to delineate the extent of the epiretinal membrane. Another application of triamcinolone is sometimes

used to identify the edge of the internal limiting membrane (ILM), either in macular pucker or in macular hole surgery. At the conclusion of the procedure a fluidair exchange is done with the appropriate gas–air mixture for tamponade used. The bubble also provides an internal tamponade that closes the inner part of the incision and reduces the risk of postoperative hypotony.

When combined with cataract surgery it may be helpful to insert the infusion trocar-cannula in the inferonasal quadrant. The infusion line is clamped, and the cataract surgeon can proceed with surgery through a temporal incision if desired. The infusion line will not disturb the phacoemulsification and can be opened after the IOL is implanted, restoring a normal intraocular pressure. A suture closing the cataract incision wound, which temporarily reduces the risk of anterior chamber shallowing during the ensuing vitrectomy, is also preferable. Removal of a cataract provides greater visualization of macular detail and more complete removal of proliferative epiretinal tissue.

In most cases both 23and 25-gauge vitrectomy instrumentation would be able to provide excellent outcomes. A smaller incision using 25 gauge would be preferred to reduce postoperative leakage and hasten recovery. It is also feasible to combine 23or 25-gauge incisions with 20 gauge in some cases to allow some sclerotomies to be self-sealing (Fig. 10.12) The increased flexibility of 25 gauge can be managed since most of the membranes peeled are in the posterior pole, and less manipulation in the periphery is necessary. However, in highly myopic eyes some of the 25-gauge instruments are shorter in length in order to increase stiffness [69] and therefore it may be preferable to use 23-gauge instruments.

Fig. 10.12 A combination of 23and 25-gauge instruments may be used to maximize the advantages of a small-gauge sutureless entry with the efficiency of larger gauge instruments, the so-called hybrid approach. This is useful in cases where vitrectomy is combined with phacoemulsification and intraocular lens insertion, placing the infusion in the inferonasal quadrant prior to phacoemulsification (keeping infusion closed) allowing the cataract surgery to proceed unimpeded from the temporal approach. The infusion is then turned on to allow easier insertion of the remaining sclerotomies

10.2.4.2 Proliferative Diabetic Retinopathy

Small-incision vitrectomy can be used in most cases of proliferative diabetic retinopathy with some modifications of technique to maximize outcomes [70–73]. Vitreous hemorrhages as well as more advanced forms of fibrovascular proliferation resulting in traction retinal detachment have been successfully managed. A vitrectomy cutter probe with smaller diameter and a cutting port located closer to the end is helpful since the tip can access fibrovascular tissue more easily, shaving the tissue from the retinal surface [Video 4]. It is estimated that the need for vitreous scissors has been reduced by approximately 50%. The curved and vertically cutting vitreous scissors used in diabetic retinopathy have smaller blades and are less curved to allow them to pass through the cannula. This may be occasionally cumbersome and managed by removing a cannula and enlarging the conjunctival incision and single sclerotomy to accommodate a 20-gauge scissors when necessary.

In diabetic vitrectomy the use of preoperative bevacizumab (1.25 mg) injected intravitreally 3–4 days before surgery has reduced the frequency and extent of intraoperative bleeding. However, it is common to see

some slight oozing of blood from areas where attachments of epicenters of fibrovascular proliferation have been removed. When this is observed, it is preferable to suture any sclerotomy openings that might appear to leak in order to reduce the possibility that a prolonged period of hyopotony may persist in the first few hours postoperatively, promoting further bleeding. A single 8-0 reabsorbable suture can be passed transconjunctivally for this closure.

Good intraoperative visualization is necessary during diabetic vitrectomy and small incision vitrectomy may sometimes require the addition of additional light. A fourth pars plana incision can be used to place a “chandelier” light with broad illumination over the intended surgical area, or a multifunction illuminatedinfusion cannula can be placed at the pars. When these are used, a strong light source (usually xenon) can provide sufficient illumination to allow the placement of a forceps and scissors through the superior sclerotomy openings for bimanual epiretinal membrane dissection. In some patients, good visualization is limited by lens opacities, and cataract surgery with IOL implantation may be suggested approximately 2 weeks prior to vitrectomy. The complexity of the fibrovascular proliferation determines whether preemptive cataract surgery is done. We choose eyes in which membrane dissection will be required peripherally to the equator or even more anteriorly to the ora serrata.

10.2.4.3 Retinal Detachment

Vitrectomy is becoming the preferred method of managing retinal detachment. Minimally invasive vitrectomy has been implemented with success [17, 74–76], although some surgeons have reported a lower rate of successful primary repair [48, 77, 78]. The differences in the outcomes are unexplained since the instrumentation used is the same. The choice of case, the location of the retinal breaks, amount of laser photocoagulation, and the vitrectomy technique may all be factors. A randomized clinical trial (with large numbers of patients) comparing small-gauge vitrectomy to 20-gauge vitrectomy would provide evidence for the safety and efficacy of the minimally invasive approach. So far, no such study has been done.

The surgical objectives for successful management of rhegmatogenous retinal detachment are to remove vitreous as completely as possible around retinal