Ординатура / Офтальмология / Учебные материалы / Ocular Traumatology Springer
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2.12 Trauma By Blunt Object: Ruptures
Ferenc Kuhn
2.12.1Introduction
Rupture is the most severe type of injury; partially responsible for the poor prognosis is the instantaneous extrusion of tissues through the wound. Much of the damage occurs at the time of impact (Table 2.11.1) – this is the part of the damage the surgeon cannot influence; however, tissue incarceration and late scarring (Fig. 2.12.1) are significant threats, and here proper and timely intervention is able to positively impact the outcome. Eyes with posterior scleral extension fare much worse than eyes with only a limbal wound [1, 7], especially if primary or secondary retinal incarceration occurs (see Chap. 2.14).
2.12.2Evaluation
With regard to evaluation, see Chaps. 1.9 and 2.11 for details. Table 2.12.1 provides hints on how to recognize an occult rupture. Artifact may make it difficult on the CT to distinguish between a rupture and an IOFB [5].
Stepping on a grape closely approximates what happens to an eye that sustains a rupture.
Paradoxically, this also works as a “release” mechanism (see Chap. 2.8). Similarly, optic nerve evulsion is rare in ruptures and much more common with contusions (see Chap. 2.10).
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Fig. 2.12.1 Retinal detachment and PVR development following a scleral rupture. This histological specimen is from the enucleated eye of a 17-year-old boy who was injured by fireworks. He had NLP vision, total hyphema, traumatic aniridia and aphakia, and a very severe vitreous hemorrhage. The primary surgery was wound closure and hyphema removal. By day 11 the retina detached; during surgery it was found to have been incarcerated into the scleral wound. Retinectomy was performed with gas tamponade, and the visual acuity temporarily improved to HM. The retina subsequently redetached, the visual acuity became NLP, and by 5 months the eye was painful with an axial length of 17 mm. 1 sclera, 2 choroid, 3 detached retina. The arrowhead shows the site of the border of the retinotomy; the arrows show the path of the “flow” of proliferative cells, originating from the sclero-choroidal wound (Courtesy of A. Viestenz, Magdeburg, Germany)
Table 2.12.1 Findings that should raise the suspicion of an occult rupture
Variable |
Finding and comment |
History |
Injury caused by large, blunt object hitting the eye with substantial |
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momentum |
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Previous ocular surgery [7] |
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Eye has high myopia |
Visual acuity |
Significant loss [11], even NLP [4] |
IOP |
Usually low [11], although a normal or even increased IOP is also pos- |
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sible |
1 i.e., no eye wall rupture is visible at the lamp.
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2.12 Trauma By Blunt Object: Ruptures |
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Table 2.12.1 (continued) Findings that should raise the suspicion of an occult rupture |
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Variable |
Finding and comment |
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APD |
Usually present [11] |
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Slit lamp2 |
Thick subconjunctival hemorrhage (Fig. 2.1.2) should raise suspi- |
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cion [10], especially if chemosis [6] is also present |
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“Step” sign3,a |
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Presence of an unexplained bulgea under the conjunctiva4 |
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(Fig. 2.12.2) |
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Shallow AC in a phakic or pseudophakic eye [4], usually accompa- |
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nied by hyphema [6] |
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Deep AC in a previously phakic or pseudophakic eye [4] |
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Peaked pupil |
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Loss of the irisa |
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Loss of the lens/IOLa |
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Strands in the anterior vitreous, usually tainted with fresh blood, |
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pointing toward the anterior sclera in one direction (Fig. 2.4.1) |
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Ophthalmoscopy |
Vitreous hemorrhage [4] |
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Strands in the vitreous, usually tainted with fresh blood, pointing |
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toward the eye wall in one directiona |
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Retinal detachment
a Pathognomonical signs
2 Occasionally the anterior segment shows only minor abnormality, yet posterior scleral rupture and vitreous hemorrhage with retinal involvement are present.
3 The curvature of the bulging conjunctiva abruptly changes.
4 The crystalline lens
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Fig. 2.12.2 Subconjunctival luxation of the crystalline lens in an eye with occult rupture. This 84-year-old woman fell and hit her previously healthy eye with a large, blunt object; the visual acuity instantly became NLP. The lens was not found preoperatively.1 Intraoperatively, the lens could be discerned under the intact conjunctiva (arrows). The 13-mm-long wound was in the limbus, and , by 12 hours post-injury the retina was already detached due to a 360° dialysis. The eye underwent primary comprehensive reconstruction; visual acuity improved to 20/50 within 72 h
1 Once it was determined that the eye is likely to have suffered an open globe injury, evaluation was stopped, deferring the determination of further details until surgery.
Rupture rarely occurs at the point of impact; the eye wall gives way almost always at its weakest point (see Chap. 1.1). Typically, the rupture, in an eye without prior open globe surgery, is found at the:
•Limbus, where the radius of curvature of the cornea and sclera intersect (Fig. 2.12.2)
•Equator, behind the insertion of the extraocular muscles, where the sclera is the thinnest
•Lamina cribrosa
In eyes with prior open globe surgery (see Table 2.2.2), the wound represents a major hazard for rupture. The risk diminishes with time but never completely disappears [9]. The length of the wound and its construction also influence the risk [9]. In the USEIR database, 6% of all eyes with open globe injury had wound dehiscence; among eyes with rupture, the rate was
i.e., length and angle of the wound lips.
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16%. The greatest danger of wound dehiscence is in an eye that has undergone PK [2].
ZCave
Complete healing of a full-thickness corneal wound takes months, but even then the resistance of the scar never reaches that of the normal cornea [3]; the same is true for limbal wounds [8].
Ruptures may also occur at sites other than described above; they may be radial and extend very posteriorly. Multiple ruptures are often present; the surgeon must make sure that all have been identified.
2.12.2Management
•Take the patient to surgery as soon as possible. The ECH risk is high until the wound is closed.
•The risk of intraoperative ECH, as the wound is reopened for toilette, increases again; be prepared to immediately close the wound if sudden major tissue prolapse occurs (see Chap. 2.8).
•Decide whether you are going to follow a staged approach or perform primary comprehensive reconstruction; in the latter case, make sure all equipment/materials will be available (see Chap. 1.8). Early vitrectomy in an eye with an unsutured wound always raises the risk of intraoperative retinal extrusion into the orbit; this is discussed in detail in Chap. 2.14.
ZCave
Careful consideration is necessary regarding primary comprehensive reconstruction (see Chap. 1.8) if the rupture is too posterior to close (see Chap. 2.3). Since retinal incarceration is virtually assured, early vitrectomy with prophylactic chorioretinectomy (see Chap. 2.14) will be needed anyway. If vitrectomy is performed before the scleral wound had time to spontaneously close, the threat of intraoperative retinal extrusion is significant.
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•Be gentle and careful when opening the conjunctiva. If the wound is radial and posterior, it is always safer to close a smaller section of the scleral wound first, and only then continue with the conjunctival dissection (see Chap. 2.3).
•360º peritomy may be necessary if the wound cannot initially be located or multiple wounds are suspected.
•Use of traction sutures is very useful in keeping the globe in proper position and/or keeping the extraocular muscle away from the operative field.
•The assistant must be careful in dealing with the traction suture. If too much tension is put on the suture, it can exert substantial pressure on the eye, and risk tissue extrusion or ECH development.
•Excise or reposit all tissues before suture closure (see Chap. 2.4). If there is a large retinal prolapse, the chance of functional improvement is very low. Nevertheless, the condition remains manageable if most of the retina can be reposited and the posterior retina remains relatively intact (see Chaps. 2.4, 2.8). Even extrusion of most of the retina is not an automatic indication for primary enucleation (see Chaps. 1.4, 1.8).
•If the scleral wound is posterior, common sense is necessary to realize that it is time to halt the intervention to avoid further tissue prolapse (see Chap. 2.3).
•If additional surgical manipulations are needed (e.g., hyphema or lens removal), do not use the traumatic wound for access but prepare controlled surgical incisions (see Chap. 2.4).
•If the wound is in Zone III, there is an increased chance of incarcerating vitreous, even retina, in the wound, despite your best efforts. This and the inevitable scarring make PVR development a high risk; consider comprehensive primary surgery or early secondary surgery with prophylactic chorioretinectomy (Fig. 2.14.2D) if appropriate (see above and Chap. 2.14). If the retina does get caught by the developing scar and PVR surgery needs to be performed, the prognosis becomes extremely poor.
i.e., avoid exerting pressure on the eye.
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Fig. 2.12.3 Principles of the “well-digging” technique for severe, subacute vitreous hemorrhage. a Preoperative condition of the injured eye: severe vitreous hemorrhage. b The initial instinct of the surgeon is to” sweep horizontally” with the vitrectomy probe. c The recommended technique, however, is to proceed vertically (“well-digging”) on the nasal side. This reduces the risk of creating a large iatrogenic retinectomy. The arrows show the primary direction of the vitrectomy probe’s movements. Table 2.12.2 provides additional details
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•If the vitreous hemorrhage is very severe and the injury is at least a few days old, surgery becomes very difficult technically for several reasons.
–The blood has started to organize, and there are multiple whitish vitreous sheets, layer upon layer, with streaks of red blood on their surface. There is also liquid red blood trapped between these layers as well as subhyaloidally.
–The sheets resemble white, detached, necrotic retina, which does not bleed when bitten into with the vitreous probe. This makes distinction between the two tissues nearly or truly impossible.
–Release of the trapped blood may give the impression that an acute hemorrhage (ECH?) is occurring.
–These difficulties force the surgeon to apply a seemingly paradoxical technique: “vertical digging,” instead of “horizontal sweeping” (Fig. 2.12.3; Table 2.12.2).
•Postoperative management (see Chap. 1.8).
Table 2.12.2 Management of eyes with very severe, subacute vitreous hemorrhage
Surgical step |
Comment |
Select a very long4 infusion |
The risk of subretinal infusion should be minimized |
cannula |
|
Place the sclerotomies at |
The risk of retinal injury during instrument introduction/ |
no more than 3 mm from |
exchanges should be minimized |
the limbus5 |
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Sacrifice the lens if neces- |
The condition of the retina determines the outcome |
sary |
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4 Six or even 7 mm |
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5 Scleral transillumination (see Chap. 2.16), but especially the endoscope (see Chap. 2.20), is of great help in selecting a safe site. Transillumination is not able, however, to determine whether the cannula is subretinal.
This condition can occur after any injury, but it is most common in ruptures; therefore its management is discussed here.
Remember, even the most careful preoperative ultrasonography may not be able to tell with reliable certainty whether the retina is detached.
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Table 2.12.2 (continued) Management of eyes with very severe, subacute vitreous hemorrhage
Surgical step |
Comment |
Before actually opening the infusion line, turn the infusion cannula’s port toward the center of the pupil, and make sure it is not occluded by vitreous or retina
Use a wide-angle endoilluminator6 but at a reduced brightness
Place the vitrectomy probe nasally
Turn the vitrectomy probe vertical (downwards) and start removing the vitreous as if digging a well with a shovel
Proper infusion flow is crucial to maintain the preset IOP. The cannula’s port must be in the vitreous cavity, the flow must be free, and the loss of intraocular fluid must not exceed supply; BSS may be lost through the wound, an enlarged sclerotomy, or through aspiration (phacofragmentation; see Chap. 2.7)
Glare from white/light-colored vitreous sheets can be very distracting and hinders fine discrimination of structures
Even if this means using the nondominant hand, the vitrectomy probe should be inserted through the nasal sclerotomy so that its position can be vertical (see next)
The surgeon’s first instinct would be to carefully “peel” or shave off the vitreous layers horizontally so that as soon as the retina is detected behind the posterior cortical vitreous, cutting can be stopped. In reality, this poses
a much greater risk for the retina: there is usually no PVD,7 and because of the resemblance of the vitreous to the retina (see above), large areas of the retina can be removed before the surgeon realizes what is happening. Proceeding vertically, albeit in a narrow funnel (“welldigging”), does not eliminate the risk of inadvertent retinectomy, but this involves only a small area of the retina and does not threaten the macula. If an inadvertent retinectomy occurs and the vitrectomy probe’s port is subretinal, its position is immediately recognized and the exact location of the retina is revealed (Fig. 2.12.3)
6 A chandelier type of light, which would otherwise allow true bimanual surgery, is not recommended. The light pipe is more useful in these eyes because the surgeon can easily change the angle of illumination to help in tissue differentiation or use it to peep into the depth of the “well” created.
7 The retina may be detached, but it is still adherent to the posterior cortical vitreous.
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Table 2.12.2 (continued) Management of eyes with very severe, subacute vitreous hemorrhage
Surgical step |
Comment |
The “well” can slowly be widened
This allows increasing access to the posterior vitreous; the vitrectomy should proceed very carefully to avoid injury to retina that is still hidden behind layers of vitreous. If fresh blood is encountered, evacuate it with passive extrusion and be patient. Although the blood is most likely not a fresh hemorrhage, it can be. The vitreous, which
is now quite mobile, often clogs the extrusion needle’s port so be prepared to use the vitrectomy probe to do the aspiration: occasional single cuts may be needed to free the port, but be very careful to avoid retinal injury, especially when working on the temporal side
Separate the posterior |
If the retina is detached, this may be very difficult; once |
hyaloid from the retina |
the cleavage plane has been identified, PFCL can be |
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used. Unless there is a posterior retinal lesion, the PFCL |
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will push the retina back and help dissect the vitreous |
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(PVD). If there is a posterior retinal break, the PFCL will |
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probably leak through8 and will not help in the creation |
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of the PVD; in such cases detaching the vitreous is either |
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very laborious or may even be impossible at this stage; |
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“viscodelamination” does not work |
Complete the vitrectomy |
Be especially meticulous in the periphery and at the |
anteriorly |
wound site (see Chap. 2.9) |
Proceed as needed, based |
The most difficult task is now completed; the intraopera- |
on the actual findings |
tive findings determine all subsequent maneuvers (laser, |
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retinectomy, tamponade, etc.) |
8 And must be removed from the subretinal space later