Pits & Pearls

PVD in RRD: In about 15% of patients with RRD, the vitreous is still attached at the posterior pole. One group at risk are myopic patients below the age of 50 years with multiple small round breaks. The vitreous may be very adherent to the retina in such cases, and trying to induce a PVD can lead to multiple iatrogenic breaks. These cases usually do very well with scleral buckling surgery. If in doubt, check the status of vitreous attachment/detachment with preoperative ultrasound before deciding to perform a vitrectomy.

Pits & Pearls

Triamcinolone and RRD: Many cases of RRD are caused by strong vitreoretinal adhesion. It may not be possible to separate vitreous and retina simply by engaging the vitreous with the vitreous cutter and pulling it off the retina – you may enlarge pre-existing breaks or induce iatrogenic breaks in some cases. If you find very strong vitreoretinal adhesions, it is advisable to ‘stop pulling’ and start ‘shaving’ the vitreous of the retina. This is facilitated by staining the adherent vitreous with triamcinolone. When staining the vitreous with triamcinolone, use minimal amounts and direct the injection it to the area of interest. Injecting too much triamcinolone may interfere with your view, and it can be cumbersome to remove this later on in the procedure.

4. Mark the breaks with endodiathermy

The key concept of all retinal detachment surgeries is to identify and treat all retinal breaks. Perform a thorough internal search for breaks following Lincoff’s rules that point to the most likely areas of retinal breaks. If you fail to identify and treat a retinal break in detached retina, failure and retinal re-detachment following vitrectomy are guaranteed. Mark the edges of the break with endodiathermy. A break, which is not marked, is hard to identify when it is attached to the underlying retinal pigment epithelium (Figs. 10.2 and 10.3).

Pits & Pearls No. 50

Macular hole in RRD: Always check for the presence of a macular hole. This is present in 2% of all retinal detachments, and if you do not consider it, chances are that you will miss it. Check either during the preoperative examination or during the surgery. This is important for prognostication and your surgery, as you may be able to perform an ILM-peeling during the vitrectomy

5. Injection of PFCL to posterior edge of break and drainage of subretinal fluid

The PFCL has three tasks in detachment surgery:

1.Stabilization of the mobile retina

2.Removal of the subretinal fluid

3.Elevation of the vitreous base

The PFCL pushes the subretinal fluid from the central pole towards the periphery

and presses it through the retinal break into the vitreous cavity. First, the PFCL is injected up to the posterior edge of the most central break, while we observe how the subretinal fluid is forced through the break into the vitreous cavity. The PFCL also has the effect that the mobile retina is attached, and a vitrectomy in the vicinity of the detached retina is less dangerous.

The following step is the drainage of subretinal fluid anterior to the break. Hold the tip of the fluid needle adjacent to the break and drain as much subretinal fluid as possible (Fig. 10.4). The residual subretinal fluid will be drained completely in a later step.

Pits & Pearls

PVD and PFCL: Make sure that you have created a posterior vitreous detachment and a sufficient core vitrectomy before injecting PFCL. PFCL and vitreous do not mix, and if too much vitreous is left at the posterior pole, multiple small bubbles of PFCL will be the result.

Pits & Pearls No. 51

Schlieren phenomenon: Inject PFCL slowly and watch for the ‘Schlieren phenomenon’. It takes some time for the subretinal fluid to be forced through a potentially small break into the vitreous cavity, and you may trap subretinal fluid if PFCL is injected too quickly. In particular in long-standing RRD, the subretinal fluid appears like a muddy stream when entering the vitreous cavity. This ‘Schlieren phenomenon’ may point to the location of the retinal break at the entry site of the Schlieren in cases of ‘unseen breaks’.

Pits & Pearls

PFCL is quite expensive. In more complicated cases, it may be necessary to perform multiple manipulations under PFCL, occasionally removing and then again adding PFCL at a later stage. If PFCL needs to be removed, one can easily aspirate it back into the injection syringe for re-injection at a later stage of the procedure.

Fig. 10.4 Drawing showing the drainage of subretinal fluid through the break after injection of PFCL

Water

Fluid needle

PFCL

cmolter

6. Vitrectomy of the tear flap and the peripheral vitreous

After ensuring the presence and completion of a PVD, the next step is to perform a trimming of the vitreous base. Start within the area of the break(s) and also remove the flap, as the vitreous traction on the flap caused the detachment. The scleral depressor in the second hand is a great help when indenting the retina (Figs. 10.5 and 10.6).

Pits & Pearls No. 52

Trimming of vitreous base: There are various ways to trim the vitreous base:

(a) bimanual technique using a scleral indentor, (b) removal under coaxial light (only with microscope illumination) by using a cotton wool swab or a scleral depressor to indent the sclera or (c) using the light fiber as an external scleral depressor (this gives you a focussed beam of light transsclerally to illuminate the vitreous base).

7. PFCL injection up to ora serrata or drainage of anterior subretinal fluid

Depending on the anterior/posterior location of the break, there is more or less subretinal fluid anterior to the break (trapped fluid). If a break is located at the ora serrata, you can drain the residual subretinal fluid with a complete PFCL fill. However, if the break is located at the equator, then a complete drainage is not possible with a complete PFCL fill. The subretinal fluid is trapped between the break and the ora serrata. In the first case, you can proceed with laser photocoagulation, and in the

Fig. 10.5 Due to the chandelier light, the surgeon has two free hands. With your left hand, you indent the retina and the tear. The right hand holds the vitreous cutter

Fig. 10.6 The flap of the tear has been removed with the vitreous cutter. This is necessary in order to remove the vitreous traction, which caused the retinal detachment

latter case, you can perform a partial laser photocoagulation and complete the laser after the fluid/air exchange in step 12.

If you want to remove the trapped fluid in this step, there are two possibilities: (1) Cut an iatrogenic break (retinotomy) close to the ora serrata and drain the fluid from there. (2) More elegant but technically more demanding is a sandwich technique as described in detail in step 12. In short, switch to fluid-air exchange. Place the opening of the fluid needle in front of the break. Now, the air will push the subretinal fluid down and out of the subretinal space through the break and fluid needle. Aspirate all water from the subretinal and preretinal space with only PFCL and air remaining inside the posterior segment. Residual subretinal fluid can be ‘milked’ out through the break using a bimanual technique with the scleral depressor and the fluid needle. Once all water is removed, inject more PFCL up to the ora serrata, now