54.4.3 Major Intraoperative Complications of SB

Fig. 54.10 A buckle too high. This eye has a high chance of developing anterior segment ischemia, becomes (even more) myopic, and shows a hourglass appearance because the wide band is pulled too tight. The technical problem with an eye having such a distorted contour is that there are many areas inside the vitreous cavity that remain inaccessible to the surgeon

54.5.1 Preoperative Examination

¥This can be kept to the minimum: making the diagnosis.64 In sharp contrast to the needs of SB or pneumatic retinopexy, the Þne details can be established intraoperatively.65

¥It is important, though, to determine whether the macula is off (timing, see above, Sect. 54.3.1) and if it is, whether it is partial (to avoid causing a macular fold; see

Sect. 31.1.2).

54.5.2 Surgical Steps

54.5.2.1 Sclerotomies

The position of the break/s does not inßuence their placement. If the RD is bullous, be careful not to insert the cannula under the retina (see Sect. 21.6).

54.5.2.2 Vitreous Removal

¥Determine if the media are sufÞciently clear to visualize the posterior retina. In the rare cases with severe VH, assume the retina is just behind the probe and proceed very cautiously from anterior to posterior; otherwise, the standard P-A approach is employed.

¥The vitreous removal must be complete (see Chap. 27), starting with a PVD (using TA to mark it),66 which should be extended as far anterior as possible. More than half of the eyes will not have a PVD posterior to the retinal tear.

64History (ßashes, curtain etc.); slit lamp/IBO; ultrasonography in the presence of fundus-blocking media opacity Ð but keep in mind that in up to a Þfth of the eyes with VH, the diagnosis of RD may be false.

65These details will also be much more accurate than any preoperative examination would allow.

66The lack of PVD does not become evident unless the surgeon actively searches for the presence of vitreous on the posterior retina.

Pearl

The key to surgical success is removal of the entire vitreous. Redetachment in the absence of PVR is almost always caused by traction exerted by the residual vitreous.

ÐIndirect evidence of vitreous being present on the retinal surface posterior to the tear is provided by the retina moving toward the probe when aspiration/ßow is activated. Conversely, if gel, rather just ßuid, is present and the probe is pushed toward the detached retina, the retina will move away from the probe (see Sect. 27.3.1).

Q&A

Q How far anteriorly should the vitreous be separated from the retina?

A In principle, the further anteriorly, the better. In some eyes it is at the equator where they become inseparable; in others it is more anteriorly. Using two instruments (such as the light pipe as the second one) can help with the separation, but eventually it becomes either impossible to detach the vitreous or its cost is too high because additional retinal tears form. This is the line at which the vitreous must be left behind but shaved to as close to the retina as possible (the rather drastic alternative is a retinectomy; see

Sects. 27.2 and 33.1).

¥The vitreous may be so adherent to the still-attached retina that if separation is attempted by using high aspiration/ßow, the 2 tissues do not separate, but the choroid is pulled off.67

¥If the retina is very mobile, the risk of eating into it with the probe is high, even when using a high cut rate at a low ßow/aspiration. Scleral indentation and/or the use of PFCL helps reduce the movement of the retina. Draining the subretinal ßuid does not help because the IMP is broken (see Sect. 26.3.2).

¥If a ßapped tear is present, it must be excised68 so that the remaining retinal edge is ßush. The entire area must be traction-free.

¥360¡ scleral indentation is used to complete the peripheral vitrectomy. Even in a phakic eye, this is relatively easy to accomplish without risking lens integrity Ð provided the sclerotomies were placed correctly (see Sect. 21.2). Pneumovitrectomy (see Fig. 14.1 and Sect. 27.3.2) is a safe and effective technique to allow maximal gel removal at the vitreous base.

¥Finally, the vitreous must be removed from behind the lens (see Sect. 27.5.3).

67Should this occur, the separation attempt must immediately be abandoned. The choroid will with time re-adhere to the sclera; there is no need for any special intervention. The choroidal detachment is more common in eyes with severe injury or if a subretinal strand (see Sect. 32.4.1) is being pulled.

68Obviously, any blood vessel bridging the tear and the retina must be cauterized Þrst.

478 54 Retinal Detachment

With the vitrectomy complete, the surgeon must decide whether to peel the ILM (see Table 54.9).

Table 54.9 ILM removal in eyes with RD

aThis is one area where I can foresee my philosophy change in the future and remove the ILM in every case.

A bullous retina is a challenge during vitreous removal because it threatens to enter the port. Low ßow/aspiration, high cut rate, scleral indentation, and keeping the retina away with the light pipe are all helpful in reducing the risk.

Pearl

A retinal break that is inferior is not by itself an indication for placing an inferior scleral buckle or using silicone oil. If the sclerotomies were properly placed (see Sect. 21.2.2) and all traction has been eliminated around the break, the risk of redetachment is not higher than with a superior break.

54.5.2.3 Intraoperative Retinal Reattachment

See Sect. 31.1.2 for details of draining the subretinal ßuid (F-A-X). Only a few additional issues are mentioned here.

¥I always mark the posterior edge of all retinal breaks69 with diathermy so that they are easily visible in an air-Þlled eye.70

ÐThe reason to mark the posterior edge is to indicate the central-most point for the laser treatment (which is done under air) so that at least 2 rows will be placed posterior to it.

ÐIf the break is large, its extension on the frontal plane must also be marked, identical to the markings seen on Fig. 54.5.

69Except if they are in a cluster and at equidistance from the ora serrata; here a single mark is sufÞcient.

70Unless it is giant tear, breaks tend to become invisible under air.