Penetrating Injuries and lOFBs

Ferenc Kuhn

2.13.1 Introduction

Penetrating and IOFB injuries have a lot in common (see Chap. 1.1), but they must be distinguished because of the retained FB's unique management implications. Even though both of these injury types have better prognosis than ruptures, the treatment can be very challenging and the outcome is ultimately determined by the expertise of the surgeon.

2.13.2 Evaluation

The most important question the evaluation should answer is whether an IOFB is present; every effort should be made to confirm its presence or lack thereof.1 If history and the test results collide, it is safer to presume that an IOFB is present. (See Chaps. 1.9 and 2.11 for details.)

By far CT is the most reliable method of finding an IOFB. For ferrous IOFBs, X-ray usually suffices, but it still has an up to 31% failure rate in detecting the splinter [4]. For nonmetallic IOFBs, the proportion of false-negative tests is much higher.

It is possible that the agent caused an occult penetrating wound in the sclera (Fig. 2.13.1). The length of the wound is, however, usually much smaller than a rupture's length.

1 Failure to do so has severe medical as well as legal consequences.

Fig. 2.13.1 Occult penetrating wound of the sclera. The patient felt a minor hit on his eye. On external inspection, a 0.5-mm conjunctival wound was seen. There is mild hemorrhage (as the patient looks down, these hemorrhages appear to be streaking toward the conjunctival wound), but no scleral wound is visible. Because history was also suggestive, a CT was performed, which identified a small IOFB (Courtesy of V. Mester, Abu Dhabi, U.A.E.)

Fig. 2.13.1 Occult penetrating wound of the sclera. The patient felt a minor hit on his eye. On external inspection, a 0.5-mm conjunctival wound was seen. There is mild hemorrhage (as the patient looks down, these hemorrhages appear to be streaking toward the conjunctival wound), but no scleral wound is visible. Because history was also suggestive, a CT was performed, which identified a small IOFB (Courtesy of V. Mester, Abu Dhabi, U.A.E.)

Pearl

The implications of an occult scleral penetrating wound are different from those resulting from a rupture. The ECH risk is much smaller if an occult penetrating wound is present, as opposed to the endophthalmitis risk, which is significant. If the retina has also been injured, it is likely to become incarcerated, and the risk of PVR is high; prophylactic cho-rioretinectomy (see Chap. 2.14) should be considered.

2.13.3 Management 2.13.3.1 Penetrating Injury

The management follows the steps outlined in Table 2.11.2.

2.13.3.2 IOFB Injury

The risk of endophthalmitis and toxicosis has a great impact on timing, although there are other factors to consider (Fig. 2.13.22; Table 2.13.1). Tables 2.13.2-2.13.4 provide details on several additional, important issues that need to be assessed. Also, a comparison of a large series of eyes with IOFB injury, encompassing a 5-decade interval, is given in Table 2.13.5.

Below is a brief review of the surgical steps in the actual management of eyes with a retained FB. The information is presented according to the location of the IOFB.3

A Controversial

As a general rule, a fresh IOFB should not be left in the eye; however, if the IOFB is verifiably inert, there is a sign or elevated risk of endophthalmitis, and no intraocular pathology has been caused, surgery may entail more complication than that to which the IOFB might lead. An individual decision must be made regarding management (see Chap. 1.4). The same dilemma arises if an old, symptomless IOFB is accidentally found (see later in this chapter).

2.13.3.2.1 Anterior Chamber

With regard to the anterior chamber:

• With rare exceptions, the entry wound should be closed and a paracentesis prepared for extraction.

• Only occasionally should a direct cut-down be employed, e.g., if the IOFB is very large or stuck in the angle or iris.

2 The understandable anxiety of the patient to have the foreign object removed from the eye as soon as possible adds to the general feeling of urgency.

3 Corneal and scleral FBs are technically not IOFBs; these are discussed in Chaps. 2.2 and 2.3, respectively.

Fig. 2.13.2 Flowchart showing the timing recommendations for eyes with IOFB injury. If the IOFB is in the posterior segment, its removal is almost always performed in the context of a complete vitrectomy (see text for further details)
Table 2.13.1 Timing of intervention in the management of eyes with IOFB injury: literature review

Published finding/recommendation

Comment

"IOFB removal within 24 h may in some clinical situations reduce the endophthalmitis risk" [12]

Triaging the cases was not random but based on surgeon availability; case characteristics were not balanced; the advantages of emergency removal therefore cannot be confirmed

"IOFB removal within 24 hours significantly reduces the endophthalmitis risk" [16]

The endophthalmitis rate was slightly higher in eyes with (7.4%) than without (5.1 %) IOFB removal; in 91 % of patients the endophthalmitis was already present when the patient presented; delay in wound closure was more important a risk factor than a delay in IOFB removal

Delay in vitrectomy and IOFB removal does not increase the endophthalmitis risk [6, 11, 17]

It is possible that the series were of insufficient power to detect the difference in outcome

Despite an average delay of 21 days from injury to IOFB removal, none of the 79 eyes developed endophthalmitis [8]

War injuries in a dry climate; severe trauma in many eyes and soil contamination may have occurred commonly

Endophthalmitis does not have an adverse effect on the outcome [9]

It is possible that the series was not of sufficient power to detect the difference in outcome; in 100% of patients the endophthalmitis was already present when the patient presented

"IOFB need not be considered an absolute indication for immediate intervention" [13]

The final visual acuity was independent of the interval between injury and IOFB removal - the results were actually better in the delayed-intervention group

"Prompt surgical intervention, the use of intravitreal antibiotics in high-risk-type injuries, and the possible use of vitrectomy surgery may reduce the incidence and severity of endophthalmitis" [18]

Of the 27 eyes, 26% had a positive intraocular culture; 17% of eyes underwent surgery later than 24 h post-injury (as late as 5 months); no case of endophthalmitis

Table 2.13.1 (continued) Timing of intervention in the management of eyes with IOFB injury: literature review

Published finding/recommendation

Comment

"There was no significant association between length of time to removal of IOFB and poor visual outcome" [26]

9% of patients presented with endophthalmitis; the median time to removal was 9 days (range 5-18 days)

Table 2.13.2 Important issues influencing the management of eyes with IOFB injury

Issue

Comment

Reliability of history

While most patients notice that an object hit their eyes and caused pain and visual loss, some people experience no adverse effect, and cannot recall any even if asked. Those who were bystanders are more likely not to have noticed the injury

Scleral vs corneal wound

Corneal entry means that the FB lost more of its momentum1 and is therefore less likely to cause serious damage [3]

Endophthalmitis risk: average vs high

High risk: lens injury [24]; soil contamination/rural setting [2]; and the presence of copper (the impact of timing is discussed in Table 2.13.1 )

Prophylactic antibiotics and method of application2

Some form of prophylaxis is recommended, even though there is no consensus in the literature as to the route of administration. It appears reasonable to use oral antibiotics (e.g., ciprofloxacin, moxifloxacin) if the risk of endophthalmitis is average; in high risk cases an intravitreal route is recommended (vancomycin, ceftazidine; see Chap. 2.17 for more details)

Wound length

The relation between wound length and the occurrence of retinal lesions due to impact is inversely proportional [15]

Location of retinal impact site

If the wound is corneal and an iris defect has also occurred, they provide trajectory information regarding the likely impact site (see Fig. 2.7.3)

Table 2.13.2 (continued) Important issues influencing the management of eyes with IOFB injury

Issue

Comment

Risk of retinal impact site

71 % for a single and 21% for two or more [17]. It is always important to carefully weigh the options regarding treatment of the impact site (Fig. 2.13.4)

Toxicosis (Table 2.13.3 shows additional details)

Copper content can lead to an acute, endophthalmitis-like condition or to chronic chalcosis if not removed in time [20]. Because of the danger of acute loss of vision, IOFBs containing copper should be removed as soon as possible [7]. Once the threat of the acute reaction passes, the toxicosis takes longer to develop than with ferrous IOFBs

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