Ординатура / Офтальмология / Учебные материалы / Ocular Traumatology Springer
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2.14 Perforating Injuries |
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4 The idea of prophylactic chorioretinectomy came to the author upon observing no PVR in eyes undergoing vitrectomy with removal of the choroid and retina in eyes with malignant melanoma. It appears that the proliferative cells do not bridge the bare sclera to seed the retina if the scleral bridge is wide enough.
5 Numerous small gas bubbles form during the procedure. In phakic eyes, these bubbles collect behind the lens if there is still vitreous there, making it easier and less risky for the surgeon to remove both the bubbles and the retrolental vitreous. In pseudophakic eyes the bubbles usually migrate away from the visual center.
6 The goal is not to cut the retina and choroid with scissors or the vitrectomy probe, but to use the diathermy’s heat to actually destroy the entire tissue here.
7 i.e., the debris should be collected
8 The lesion is posterior to the equator.
ZPearl
The urgency to perform primary comprehensive surgery in an eye with rupture lies in the risk of retinal incarceration at the time of wound closure; the more posterior the wound, the higher this risk. In a perforating injury, the exit wound is rarely large enough to incarcerate the retina; the danger lies in events occurring postoperatively.
2.14.3.1Intraoperative Wound Reopening
2.14.3.1.1 Risk Factors |
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The risk factors are as follows: |
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• |
Large wound |
• |
Very fresh injury |
• |
Older patient |
• Significantly raised IOP (e.g., to stop an intraoperative hemorrhage).
2.14.3.1.2 Prevention
Prevention consists of:
400 Ferenc Kuhn
> Fig. 2.14.4 Schematic representation of IOP control during vitrectomy. a Traditional setup: the infusion bottle is directly connected to the eye through the infusion line. The IOP is regulated by up-or-down movements of the bottle, either electronically via the vitrectomy machine1 or manually. The problem with this setup is that the true IOP value is never known since there is no adjustment based on the distance of the patient’s head (eye) from the floor. b If (a) the air pump of the vitrectomy machine is used to drive the pressure inside the infusion bottle, and (b) the drip chamber of the infusion bottle is at the same distance from the floor as the patient’s eye, the air pressure set on the vitrectomy machine gives an accurate, digital reading of the actual IOP [6].
1 Newer machines even translate the bottle’s distance from the floor to mmHg.
•Delaying vitrectomy until the posterior wound is firmly closed
•Controlling and monitoring the IOP very closely during vitrectomy (Fig. 2.14.4)
2.14.3.1.3 Recognition
The pathognomic signs are:
• Full-thickness sclero-chorio-retinal folds radiating from the wound
• Rapidly collapsing globe due to increased intraorbital pressure exerted on the posterior sclera
2.14.3.1.4 Management
With regard to management:
•In the unlikely event that a posterior wound reopens during vitrectomy, the infusion must be turned off or at least significantly lowered so that additional fluid loss into the orbit is stopped.
•Silicone oil injection should be started as fast as possible, which reconstitutes the IOP and prevents further collapse of the eyeball. The amount of silicone oil implanted is usually half to two-thirds of the volume the eye would normally take.
As mentioned previously, the risk of wound reopening is much smaller if the injury is perforating, rather than a rupture.
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DO:
•try to verify whether the injury was penetrating or perforating
•if you are uncertain or if the injury is likely/definitely perforating, consider vitrectomy with prophylactic chorioretinectomy within the first few days post-injury
DON’T:
•try to suture-close an exit wound that is too posterior for convenient access
•panic in the unlikely case of intraoperative reopening of the exit wound: silicone oil implantation allows controlling the situation and the abandoned procedure can be completed in a subsequent surgery within days
Summary
Perforating injuries typically have very poor prognosis. Fortunately, in most eyes the outcome is poor not because the injury caused irreversible damage upon impact but because of subsequent scarring originating
from the exit wound. Early prophylactic chorioretinectomy is a very promising procedure in preventing this complication and improving the functional outcome.
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References
[1]Cardillo JA, Stout JT, LaBree L, Azen SP, Omphroy L, Cui JZ, Kimura H, Hinton DR, Ryan SJ (1997) Post-traumatic proliferative vitreoretinopathy. The epidemiologic profile, onset, risk factors, and visual outcome. Ophthalmology 104: 1166−1173
[2]Cleary PE, Ryan SJ (1979) Experimental posterior penetrating eye injury in the rabbit. II. Histology of wound, vitreous, and retina. Br J Ophthalmol 63: 312−321
[3]Kuhn F, Mester V, Morris R (2004) A proactive treatment approach for eyes with perforating injury. Klin Monatsbl Augenheilk 221: 622−628
[4]Schwartz S, Mieler WF (2002) management of eyes with perforating injury. In: Kuhn F, Pieramici D (eds) Ocular trauma: principles and practice. Thieme, New York, pp 273−279
[5]Vatne HO, Syrdalen P (1985) Vitrectomy in double perforating eye injuries. Acta Ophthalmol (Copenh) 63: 552−556
[6]Witherspoon CD, Morris R, Goggans WE (1986) Automated regulation of fluid infusion pressure during vitrectomy. Arch Ophthalmol 104: 1551
2.15 Injury Involving the Entire Globe
Ferenc Kuhn, Robert Morris, C. Douglas Witherspoon
2.15.1Introduction
Open globe injuries may cause substantial damage to the eye, making the situation akin to that of a polytraumatized person: the condition of one pathology influences the condition and treatment of another (Fig. 2.2.14). The most serious of the potential scenarios is when the retina requires major surgery urgently but the cornea has become opaque and interferes with visibility. Such an injury represents one of the most challenging indications for the ocular traumatologist, and the number of viable options is limited.
2.15.2Evaluation
The cornea is so badly damaged that even the color of the iris may be impossible to determine at the slit lamp (Fig. 2.2.14). The condition of the cornea may be due to the presence of multiple wounds with excessive edema and/or blood staining. The lens, if present at all (Fig. 2.12.2), is rarely clear. The vitreous hemorrhage is usually very severe, and the retina is often incarcerated in the wound. Early retinal detachment and the development of PVR are frequent complications. The visual acuity is typically in the NLP to HM range. The treatment should not be based on whether the visual acuity is NLP or greater (see Chap. 1.8).
Occasionally, a contusion can also inflict such damage.
406 Ferenc Kuhn, Robert Morris, C. Douglas Witherspoon
2.15.3Management Options
The outcome of the injury is primarily determined by the condition of the postequatorial retina. The main question is to what extent the traumatized cornea interferes with posterior segment surgery. The following management options are available:
•No surgery. Abandoning the eye is equal to a death sentence: spontaneous improvement is unreasonable to expect. Early phthisis is likely.
•Delayed surgery. Vitrectomy is performed only when the cornea’s interference with visibility is sufficiently reduced. Unfortunately, this is usually very late, and the prognosis of the injury is extremely poor.
•Timely but limited surgery. Vitrectomy is performed within the first 2 weeks, but it is not carried to completeness because the condition of the cornea does not permit it. The prognosis is very poor.
•Incremental surgeries. Posterior segment surgery is done in several surgical sessions. Even though performed early, each vitrectomy is incomplete, depending on the condition of the cornea. The disadvantages far outweigh the benefits; the prognosis is very poor.
•Endoscopy-assisted vitrectomy. The endoscopic approach has the advantage of bypassing the corneal interference (see Chap. 2.20). It also makes corneal transplantation potentially avoidable. Endoscopy-as- sisted vitrectomy has its own, significant technical difficulties, mainly that is performed without stereoscopy and surgery is not bimanual, and it requires considerable experience. Another factor to consider is the inability to postoperatively inspect the retina until the media opacity clears. Nevertheless, EAV is a viable option and should be high on the surgeon’s consideration list. In summary, the main advantage of the endoscope over the TKP is that the patient is spared the risks associated with PK if the corneal opacity is temporary.
Presuming that the optic nerve is not injured, the tissue (other than the postequatorial retina) with decisive impact on the outcome is the ciliary body (see Chap. 2.8). Not all eyes sustain irreversibly damage; with time some corneas recover.
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ZCave
Use of the endoscope in an eye that has sustained major damage to both the anterior and posterior segments demands a surgeon who has great experience in both ocular traumatology and endoscopy (see Chap. 2.20).
•Temporary keratoprosthesis vitrectomy. Considering all options this is the most promising alternative. Most trauma specialists have sufficient experience in vitrectomy as well as in corneal grafting; if not, two specialists should operate in a joint procedure (see below). In summary, the main advantage of the TKP over the endoscope is that it provides early vision restoration to the patient and retinal inspection to the surgeon.
ZPearl
There is no justification for abandoning eyes with serious anteriorand posterior segment trauma. Both the endoscope and the TKP allow the surgeon to perform uncompromising vitrectomy in the subacute period.
2.15.3.1TKP Vitrectomy
The TKP is an artificial, temporary graft, replacing the patient’s nontransparent cornea for the duration of posterior segment surgery (Fig. 2.15.1). Independent of design and material (Table 2.15.1), the TKP provides a crys- tal-clear view during vitrectomy while providing for the necessary closed globe environment. Ideally, a standard PK is performed at the conclusion of vitrectomy, replacing the TKP with donor tissue (Fig. 2.15.2). If a donor tissue is unavailable, two temporary solutions are available: the TKP is left in the cornea or the patient’s own damaged cornea is used as a graft.
Both are acceptable for a few days, and either of these solutions is preferred to delaying the vitrectomy.
408 Ferenc Kuhn, Robert Morris, C. Douglas Witherspoon
Fig. 2.15.1 The temporary keratoprosthesis (TKP) device intraoperatively. As opposed to a completely nontransparent cornea (see Fig. 2.2.14), the Landers TKP provides unhindered viewing of the retina. Use of a wide-angle system or a contact lens for fine epiretinal work are both possible
Fig. 2.15.2 PK to complete the procedure. At the end of surgery, a corneal graft is placed. There is excellent red reflex and the retina is attached
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2.15 |
Injury Involving the Entire Globe |
409 |
Table 2.15.1 A comparison of two temporary keratoprosthesis designs |
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Variable |
Eckardt [1] |
Landers [10] |
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Diameter |
7 or 8 mm |
7.2 or 8.2 mma |
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Phakic version available |
Yes |
Yes |
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Suture placement |
Up to surgeon |
Predetermined holes |
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Reusable |
Yesb |
Yes |
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Material |
Silicone |
PMMA |
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Manufacturer |
DORC1 |
Ocular instruments2 |
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A third device, the Aachen keratoprosthesis, has also been used on a temporary basis [3] a Provides 2.3× magnification and 30° field of static view
b Limited because the sutures eventually destroy the rim of the device 1 Zuidland, The Netherlands
2 Bellevue, Washington
!Pitfall
Timing is a critical issue. There is no rational reason to delay TKP vitrectomy for weeks; if intense topical corticosteroid therapy is employed after the initial surgery (see Chap. 1.8), surgery can be scheduled as early as a few days post-injury. The ideal time to perform TKP vitrectomy is within a few days, not after 3 weeks.
2.15.3.1.1The Surgeon
Depending on how (sub)specialized ophthalmology in the particular country is, TKP vitrectomy may be performed by a single individual from start to finish, or by two teams, an “anterior” and a “posterior” (Table 2.15.2). If a single surgeon performs the entire operation, he or she must be a vitrectomy specialist who is also experienced in anterior segment surgery, not the other way around: the major difficulty of surgery lies in dealing with