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The more posterior a scleral wound, the more difficult it is to avoid incarcerating vitreous, choroid, even retina, in the suture track.

• The vitrectomy probe should be used to trim the vitreous at the level of the wound. The probe should not, however, be pushed deep inside the wound to avoid injuring the choroid.

• The assistant plays a crucial role in reducing the incarceration rate. Keeping a spatula over the wound as the surgeon introduces the suture, the assistant should gently push/hold the prolapsing tissues back.

• Interrupted, never running, sutures are to be used (Fig. 2.3.2).

8 i.e., holding the sclera against the movement of the spatula.

Fig. 2.3.2 Radial wound in the anterior sclera. a The conjunctiva has been carefully dissected to expose the scleral wound, which is approximately 4 mm long and makes a slight "S" curve. There is no tissue prolapse, but the dark color of the underlying uvea is visible at the bottom of the wound. b Closure is with interrupted, 8-0 vicryl sutures.

• The intended suture depth is ~80%. Unlike in the cornea, tissue edema is rarely an issue. If the suture is a 100% deep, this is not a problem unless the wound is posterior to the ora serrata; hemorrhage from the choroid is extremely rare, but any retinal injury must be avoided. Too shallow a suture track threatens with the suture "cheesewiring" as it is tightened.

• To prevent gaping, it is better to use an increased number of sutures, rather than ones with longer bite (see Chap. 2.2), especially in the anterior sclera, to avoid astigmatism.

• Unlike with corneal wounds, forceps use is mandatory to securely grasp the resistant sclera as the needle passes through; a firm grab also reduces the risk of inadvertent needle movement, which could push the needle holder against the globe and raise the IOP.

• It is often beneficial not to pass the needle through both wound edges with a single sweep, but introduce the needle on one side only, pull the

Fig. 2.3.2 Radial wound in the anterior sclera. a The conjunctiva has been carefully dissected to expose the scleral wound, which is approximately 4 mm long and makes a slight "S" curve. There is no tissue prolapse, but the dark color of the underlying uvea is visible at the bottom of the wound. b Closure is with interrupted, 8-0 vicryl sutures.

suture through as far as the tying will later require, then introduce the needle on the other side.

• Even when the wound is underneath an extraocular muscle, closure can often be accomplished without removing the muscle: the assistant should gently hold it away using a muscle hook or a suture.9

• If an extraocular muscle needs to be taken down, it should be carefully done so that it does not get "lost into orbit".10 Two sutures should firmly secure the muscle before it is severed, and two sutures should be used to fixate it back to the sclera.

• The more posterior the wound, the more difficult it is for the assistant to provide access to the operative field, for the surgeon to executive his planned maneuvers - and to do all this while avoiding pressure on the eye. Even minimal pressure can lead to ECH or retinal incarceration. The two key issues are: how to do the closure and when to stop it.

• The "close-as-you-go" technique for posterior wounds means that the wound is closed sequentially; the details are explained on Fig. 2.3.3.

• The surgeon needs both of his hands for suturing; the assistant's role is again crucial in providing access without pressure. The assistant's job is twofold: use of a properly sized retractor" to keep orbital fat and conjunctival tissues from collapsing onto the surgical field from the outside; and use of a spatula to hold back tissues from prolapsing into the wound from the inside.

9 The assistant must find the right balance between avoiding pressure on the globe while providing sufficient and convenient access for the surgeon for suture introduction.

10 The surgeon's attention is almost singularly focused on the wound, and there is always the risk of a "silly" mistake when performing tasks that in the "fog of war" appear as of secondary importance.

11 Ideally, the retractor is large so that it is able to keep all tissues away from the operative field, but the retractor may have to be "downsized" so that it does not become a physical obstacle interfering with the surgeon's own instruments. The assistant must be alert throughout the procedure and cautiously change the position of the retractor if necessary as the surgeon's tools are moved around.

Fig. 2.3.3 Radial wound in the posterior sclera: the "close-as-you-go" technique. a The conjunctiva is dissected anteriorly to confirm posterior continuation of the scleral wound. Even if the scleral wound's endpoint is not reached, the conjunctiva is not opened further posteriorly (see the text on details regarding cleaning the scleral surface). b The exposed scleral wound is closed with sutures. The direction of suture introduction is anterior to posterior: the "50% rule" does not apply. c The conjunctiva is dissected further posteriorly, avoiding any pressure on the sclera.1 Dissection should be stopped at a convenient point to allow suturing the newly exposed sclera (not shown here). Once the risk of exerting pressure on the globe is high and tissue extrusion becomes unavoidable, suturing of the sclera must stop, and the wound is left to spontaneously scar over (see the text for more details). The conjunctival wound is meticulously closed, and the patient must wear a shield over the eye for a few days

Fig. 2.3.3 Radial wound in the posterior sclera: the "close-as-you-go" technique. a The conjunctiva is dissected anteriorly to confirm posterior continuation of the scleral wound. Even if the scleral wound's endpoint is not reached, the conjunctiva is not opened further posteriorly (see the text on details regarding cleaning the scleral surface). b The exposed scleral wound is closed with sutures. The direction of suture introduction is anterior to posterior: the "50% rule" does not apply. c The conjunctiva is dissected further posteriorly, avoiding any pressure on the sclera.1 Dissection should be stopped at a convenient point to allow suturing the newly exposed sclera (not shown here). Once the risk of exerting pressure on the globe is high and tissue extrusion becomes unavoidable, suturing of the sclera must stop, and the wound is left to spontaneously scar over (see the text for more details). The conjunctival wound is meticulously closed, and the patient must wear a shield over the eye for a few days

1 This is the most important warning for the assistant who uses some type of retractor to make the operative field accessible for the surgeon (see text for further details).

• One useful trick to "increase the number of hands without increasing the number of hands"12 is to put two sutures into the conjunctiva first, and lift the conjunctiva up with these sutures. The sutures can be held against the shaft of the retractor so a single hand is now holding three "tools."

• Another trick is to not cut the proximal, just introduced scleral suture but to use this as a traction suture to gently pull and turn the globe. This suture can be clamped to the drape or be left very long and be held by the OR nurse - hers is now the fifth hand, but it is outside the immediate operative field. This second option is more advantageous than the clamping version since the traction suture is adjustable.

• Regardless of how effective and nontraumatic the assistant is in using the retractor, the wound may extend too far posteriorly to allow closure without increasing the threat of (further) extruding intraocular tissues and ECH.

Selected pathologies in eyes with full-thickness scleral wound, recorded in the USEIR database, are given in Table 2.3.1.

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