From day 2 to day 7, we recommend ‘sitting up’ if all breaks are above the horizontal meridian. If inferior breaks are present, the posture should support the breaks; for example, ‘left cheek to pillow’ in a break in the nasal inferior quadrant of the left eye. If breaks in the superior and inferior periphery are present, a supine position ‘flat on the back’ or ‘alternating sides, left and then right cheek to pillow’ are recommended. Posture should be carried out for a week, day and night, for a minimum of 50 min on the hour.

10.2Retinal Detachment Complicated by Proliferative Vitreoretinopathy (PVR)

The surgical treatment of PVR detachment is one of the most challenging vitreoretinal surgeries, because the removal of membranes is technically very complex. If you place an encircling band, perform the surgery under general anaesthesia. There is some controversy concerning whether it is necessary to place an encircling band in PVR detachment. Previously, an encircling band for PVR detachment was a must; today, it is performed less often.

In a mild PVR detachment, we do not use an encircling band. In a more pronounced PVR detachment, we place an encircling band. You can also start the surgery without an encircling band, and then later if the retina does not attach, place an encircling band.

Regarding the strategy of PVR surgery, two schools can be distinguished. One school (US) puts the emphasis on staining and meticulous peeling of all epiand subretinal membranes. The rationale is if you leave membranes at the edges of the retinotomy, then they will contract and you are forced to perform a more central retinotomy. And if you leave membranes at the posterior pole, then the whole retina will contract. The other school (HH) places the emphasis on early and relatively large retinotomies. Only substantial epiretinal membranes are usually peeled with this approach.

Overall, PVR surgery consists of the four major tools of membrane peeling, retinotomy, silicone oil tamponade with optional encircling band.

DVD

Video 15a–c PVR detachment, peeling techniques for PVR detachment and PVR detachment secondary to trauma

Instruments

1.Encircling band

2.4-port trocar

3.120D lens, for peeling: 90D lens

4.Chandelier light

5.Vitreous cutter

6.Endodiathermy

7.Endolaser

8.Fluid needle

9.Scleral depressor

10.Membrane pic

11.Eckardt forceps

If available

12.Knob spatula

13.Crocodile forceps

14.Straight vitreous scissors

15.Vertical (retinotomy) scissors

16.CRVO/neurotomy knife

Dye

Trypan blue

Tamponade

Intraoperative: PFCL

Postoperative: Light and heavy silicone oils and occasionally long-acting gases

Individual steps

1.Encircling band

2.4-port system

3.Phacoemulsification

4.Vitrectomy

5.Staining of the membranes with trypan blue

6.Peeling of PVR membranes

7.Check if retina attaches under air or PFCL

8.Retinotomy

9.Photocoagulation of breaks

10.Tamponade

11.Removal of the trocars

1. Encircling band

Perform a perilimbal conjunctival opening over 360º. Place traction sutures beneath the four horizontal muscles. Then the encircling band is placed under the muscles. Start with the lateral rectus muscle, then superior, medial and then finally inferior. It should be noted that the encircling band is placed beneath the entire muscle; otherwise it may cause ischaemia. You may take a surgical forceps as help. It is important to make sure that the encircling band does not rotate. The open ends should be placed in the temporal quadrants. Then the encircling band is sutured with mattress sutures to the sclera, quadrant after quadrant.

Regarding positioning of the encircling band (Supramid 4-0, 5-0 polyester from Alcon), there are several guidelines: Usually, the encircling band is positioned on the equator. A good clinical guideline is to identify the vortex veins on the sclera. The equator is exactly halfway between the exiting vortex veins and the insertion of the recti muscles. Alternatively, you can slightly rotate the globe and judge where the equator is. Finally, you can measure the distance from the limbus: A good rule of thumb is to use the axial length divided by two as the distance from limbus to the mid of the encircling band.

Do not suture in the quadrant of sleeve placement as yet. First attach the Watzkesleeve to the silicone band. The sleeve is fastened on a straight clamp, and both ends of

the silicone band are inserted in the sleeve. Then the sleeve is removed from the clamp. Subsequently, the silicone band is sutured to the inferotemporal or superotemporal quadrant of the sclera. Do not tighten the encircling band before placement of the trocars; otherwise there will be a sharp rise in intraocular pressure with a significant decompression when you place your first trocar. We recommend tightening the encircling band towards the end of the procedure. The two loose ends are pulled until the encircling band sits tight on the sclera and you see an impression of the retina. With a constriction of the globe of approximately 10% (i.e. 7 mm constriction of the cerclage), you are on the safe side. (Caution: A too tight encircling band can cause anterior ischaemic syndrome, pain and a venous outflow obstruction).

2. 4-port system

3. Phacoemulsification

4. Vitrectomy

(See surgery for retinal detachment above)

Pits & Pearls No. 57

Posterior synechiae: How do you remove posterior synechiae? (1) Simultaneous injection of viscoelastics and delamination with the viscoelastics cannula. (2) If the adhesions are too strong, you can cut them with a (curved) vitreous scissors. If the pupil is fixed with a reasonable pupil size, it is sometimes advisable to perform this at the end of the procedure before the tamponade is installed. This is because dissection of synechiae may cause a significant haemorrhage in the anterior chamber and you start a complicated case with a poor view, potentially a small pupil and the need for cleaning up an anterior chamber haemorrhage.

5. Staining of the membranes with trypan blue

Some PVR membranes cannot easily be detected, we recommend therefore to stain the membranes with trypan blue. Inject the dye ideally in an air-filled vitreous cavity. In a water-filled vitreous cavity, it requires a larger amount of dye and a longer time to aspirate the dye. In an air-filled vitreous cavity, you can drop the dye directly on the membranes and reach selectively a higher concentration of the dye and a better staining of the membranes (Fig. 10.16).

6. Peeling of PVR Membranes

The peeling of PVR membranes is very laborious and time consuming. Begin at the posterior pole and work your way up to the periphery. When you peel the PVR membranes, you have to work two-handed and dissect bluntly without scissors. Depending on the strength of the membrane, in one hand you hold an Eckardt forceps or a crocodile forceps and in the other hand the membrane pic. Grasp the

Fig. 10.16 Drop trypan blue in the air-filled eye on the membranes, in order to visualize them better. Always stain the posterior pole as well because there are often membranes here, which can be easily removed

membrane with the forceps and pull it up a little bit with help of the membrane pic. Then you switch the membrane pic for the knob spatula and delaminate the membrane of the retina with its blunt tip. It is important to identify the correct plane; this is the key to successful membrane peeling. Find the gap between the membrane and the retina and work your way along this gap with Eckardt forceps and the knob spatula. You can also work well with Eckardt forceps in one hand and the crocodile forceps in the other.

If you fail to mobilize the membrane, although you have identified the gap, you can take the straight scissors and cut the membrane off the retina while pulling it (Fig. 10.17). The straight scissors are especially needed for the circular membranes in the periphery. Do not use scissors for the central membranes in order to avoid breaks.

Pits & Pearls No. 58

Removal of PVR membranes: After silicone oil tamponade, peripherally located membranes in particular are very difficult to mobilize from the retina. A neurotomy (CRVO) knife can be very helpful. With its help, you can delaminate the membrane of the retina, and with countertraction of the forceps in the second hand, you can pull/draw it from the retina (Figs. 10.18–10.22).

7. Check if retina attaches under air or PFCL possibly retinectomy

The goal is to mobilize the retina. To check whether the retina is sufficiently mobile, inject air, drain the subretinal fluid and examine whether the retina attaches. If the retina does not attach, perform an air/fluid exchange and continue working and that means in more precise terms: peeling or retinotomy. Alternatively, use a PFCL tamponade. Again, a retina that does not flatten under PFCL will not flatten under any other tamponade.

Fig. 10.17 Also in PVR detachment, membranes can be removed more easily with bimanual surgery. Here the Eckardt forceps grasps the membrane, and the straight vitreous scissors cut it

Fig. 10.18 PVR membranes can be peeled well with the CRVO-knife and the Eckardt forceps. If you work bimanually, you can perform countertraction

Fig. 10.19 Inferonasal PVR detachment after primary detachment surgery. The white membranes are contracted posterior hyaloid, which was not completely removed in the first surgery

Fig. 10.20 The same eye. After complete bimanual removal of the posterior hyaloid, the retina reattached completely. Therefore, only a gas tamponade was performed

Fig. 10.21 An example for a PVR detachment after an unsuccessful buckle surgery

Fig. 10.22 The same eye after extensive peeling, laser and silicone oil tamponade. No retinectomy was performed

Fig. 10.23 Retinotomy in an eye with PVR detachment. First cauterize the retina. Then cut with the vitreous cutter along the cauterized retina (approx. 300 cuts/min)

Fig. 10.24 Now a fluid against air exchange is performed. It is important to drain the fluid completely from the edges of the retinectomy

8. Retinotomy

When performing a retinotomy, two golden rules apply: (1) place the retinotomy as peripheral as possible, ideally at the ora serrata and (2) make it larger than you think. As a rule of thumb, use the area of contracted retina as your guidance and add at least one clock hour on each side. If the retinotomy is placed at the ora serrata, diathermy is usually not necessary, as the first bit of retina is almost avascular. If you have to go more central than this, we recommend that you perform diathermy first in order to minimize the risk for haemorrhages that are both cumbersome to remove and may also trigger more PVR postoperatively.

Then cut the retina with the vertical scissors or the vitreous cutter (Fig. 10.23). If you have to place the retinotomy more centrally, remove all retina anterior to the retinotomy edge with the vitreous cutter; otherwise this ischaemic retina may cause rubeosis iridis. Use a PFCL fill to check if the retina flattens completely. If not, start again either with more membrane peeling or extent the retinotomy. An important part of the surgery is the fluid-air or PFCL-silicone oil exchange. All water (BSS) needs to be removed from the edge of the retinectomy (Figs. 10.24 and 10.25). Otherwise you will have ‘slippage’, i.e. the posterior retina slides towards the posterior pole.