RD, Tractional and Combined

55.1General Considerations1

55.1.1 Characteristics of the RD

Tractional RDs are recognized by the presence of preor subretinal membranes (bands/strands)2 and by the concave profile of the detached retina. The traction exerted by the membranes is stationary; the height and shape of the RD do not change with the position/movement of the eye/head.

Such membrane-related traction is also the dominant element in a combined RD; the presence of the retinal break does not determine the appearance or behavior of the RD, but it does have management implications (see below).

•If the eye had no surgery, the secondary break is usually small and often hidden underneath a membrane.

•In an operated eye3 the newly developed break is usually larger and has a typically oval shape (see Fig. 14.4).

1As discussed in Chap. 54 and shown in Table 54.1, even a rhegmatogenous RD is almost always caused by traction, but, traditionally, the term “tractional RD” is preserved for eyes in which there are clearly visible membranes or strands in front or underneath the retina. These elastic structures lead to the RD, without the need for, and presence of, a retinal break.

2For simplicity, all these structures, regardless of their size and shape, are referred to as “membrane” in this chapter.

3That is, recurring RD.

F. Kuhn, Vitreoretinal Surgery: Strategies and Tactics,

DOI 10.1007/978-3-319-19479-0_55

55.1.2 Management Principles

Because the traction is not dynamic, bedrest and bilateral patching do not change the height or size of the detachment. For the same reason, the progression of the RD is slow, even if a break is present.

Surgery is thus even less urgent than in eyes with a rhegmatogenous RD; conversely, it is even more crucial in these eyes than in those with a rhegmatogenous RD to completely eliminate the preretinal traction. Subretinal membranes do not require complete removal, breaking them into two may be sufficient, and those that may stretch enough to allow retinal reattachment in spite of their presence may be left behind (see Sect. 32.4).

Pearl

The proliferative process in front of the retina, as opposed to one that is subretinal, has a higher tendency to spread and recur.

If the membranes are vascularized, 2–3 days preoperatively an intravitreal bevacizumab injection should be given (see Sect. 52.1).

55.2Surgical Technique4

•Always perform a total vitrectomy.

– Depending on the etiology, a PVD may be complete, anomalous, or absent.

•Identify all preretinal membranes and remove them in their entirety.

•Before trying to remove the subretinal membranes, make sure that all preretinal membranes have been removed. This is especially important if a retinectomy is required.

Pearl

Increased mobility of the retina, which in an eye with rhegmatogenous RD makes the surgery technically more difficult, is a good sign in an eye with TRD: it is a sign that the tractional forces have been eliminated.

•In the periphery it may be impossible to separate the vitreous from the retina. In such cases a retinotomy must be performed central to the line of no separation, and the entire peripheral retina-vitreous-membrane complex needs to be removed (see Sect. 33.1).

4 More details are found in Chap. 32 as well as in Chaps. 52 and 53.

•The ciliary body must be thoroughly cleaned to reduce the risk of any future scar tissue destroying it and leading to phthisis (see Sect. 32.5).

•If the retina is shortened, retinectomy and SB are the two options to consider.

•Once an iatrogenic break is caused in an eye undergoing surgery for a TRD,5 it becomes an absolute necessity to remove all tractional forces in the vicinity of this break, even at the cost of causing more breaks.

•Unless the detachment is very shallow, the subretinal fluid should be drained through the existing break or through a newly created retinotomy.

Q&A

Q What are the criteria for selecting the site for the drainage retinotomy?

A It should be superior to the horizontal meridian, in a location that is central enough to allow complete drainage during a F-A-X yet peripheral enough for the resulting absolute scotoma not to be noticeable by the patient. It should be as far away from major blood vessels as possible (see also Sect. 32.4.1).

–As a reminder, always use diathermy to create the retinotomy. It not only prevents bleeding but also allows easy identification of the break in the airfilled eye.

•The air-test (see Sect. 31.1.2) helps determine whether a subretinal membrane will prevent retinal reattachment.

•For tamponade, silicone oil should be the default option6 since it has several advantages, including the following (see also Sect. 35.4.3):

–Prevention of postoperative bleeding.

–Allowing a clear retinal view from postoperative day 1.

–Reduction in the recurrence rate.

–Prevention of rapid retinal collapse in case of a recurrence.

5That is, making it a combined RD.

6If the RD involves only a small area and no break is present, there is no need to use oil.