Perforating Injuries

Ferenc Kuhn

2.14.1 Introduction

Eyes with a perforating injury1 pose unique challenges for the surgeon because access to, and therefore closure of, the posterior (exit) wound is usually impossible, making retinal incarceration in the wound likely. This incarceration may occur primarily (i.e., at the time of the injury or during wound closure if it was possible to suture it) or secondarily (i.e., as the scar forms at the wound). Presence of a posterior (exit) wound therefore has important management but also prognostic implications: in a metaanalysis of 15 published reports, the anatomical success rate was only 69%, the functional2 only 56% [4].

2.14.2 Evaluation

The possibility of an exit wound should be suspected based on information gained from history; objects that are sharp, short in one diameter but long in the other, and have significant momentum are more likely to perforate the eyeball than objects that are large and blunt. Detailed knowledge of the

1 An injury with internal scleral (although not full thickness) or at least choroidal involvement may have similar consequences to a trauma that is truly perforating, and should be treated accordingly.

2 Defined as a final visual acuity of 5/200 or better.

object's characteristics (e.g., size and shape) along with the circumstances of the injury (e.g., the force of the strike, the patient's distance from the event) must be sought - information of the object and the injury is necessary to make an intelligent prediction.3 (See Chaps. 1.9 and 2.11 for details on evaluation.)

2.14.3 Management

In general, the steps outlined in Table 2.11.1 should be followed; there are, however, additional factors to consider:

• Wound closure. The exit wound is rarely located anteriorly enough to allow convenient access and suturing. Forceful inspection and suturing of the wound must be avoided (see Chap. 2.3).

• Spontaneous closure of the wound. This starts by an outside-in mechanism4 within hours [2], and clinical experience shows that in 24 h most wounds are sealed with sufficient strength so as to withstand the typical IOP values employed during vitrectomy.

• Timing of reconstruction. Whether a staged approach or a primary comprehensive surgery is performed depends on factors described previously (see Chaps. 1.8, 2.11, 2.12). As a general rule, it is much less urgent to indicate primary comprehensive surgery in an eye with a perforating injury compared with a ruptured eye.5

• The PVR threat remains significant (Table 2.14.1), even with early vitrectomy and laser treatment, and despite the use of scleral buckling [5].

3 A good example is one of the author's latest cases: an 11-year-old boy was injured while sharpening a stick with a knife. He was pulling the pocket knife toward himself, the knife slipped, and caused a 9-mm-long corneal laceration; the iris and lens were also injured. To cause such a long wound, the blade had to penetrate deep into the eye. A perforating injury was therefore suspected, and confirmed during vitrec-tomy.

4 i.e., from the episclera inward.

5 The wound is smaller; therefore, the incarceration is more likely to be secondary (see above).

Table 2.14.1 The PVR rates and visual outcomes in different types of injury (%).

Injury type

PVR rate [1]

Final visual acuity'

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