(1)
St. Johns, FL, USA
(2)
Helen Keller Foundation for Research and Education, International Society of Ocular Trauma, Birmingham, AL, USA
(3)
Consultant and Vitreoretinal Surgeon, Milos Eye Hospital, Belgrade, Serbia
(4)
Consultant and Vitreoretinal Surgeon, Zagórskiego Eye Hospital, Cracow, Poland
27.1 The Rationale for PPV
In a few indications, the surgeon’s only goal is to remove the vitreous, but in most cases, PPV is a means to accomplish a variety of additional goals such as releasing VR traction.
Pearl
The original term “vitrectomy” does not truly characterize the field today when most cases also involve retinal work. “Vitreoretinal surgery” is therefore a more proper term, but even this cannot fully encompass the technique’s full spectrum.
Table 27.1 lists a variety of conditions in which PPV is one of the treatment choices if not the most effective or only treatment option. In the absence of the vitreous gel, the disease would:
Table 27.1
Selected indications for PPV*
Indicationa | Comment |
|---|---|
AMD, dry | To address the VR traction and improve the oxygenation |
AMD, wet | Removal of the subretinal membrane or retinal translocation is very rarely done today, but remains an option in a few, carefully selected cases |
Anterior segment reconstruction | There are many conditions in which the anatomy of the anterior segment cannot or should not be restored without the use of the probe |
BRVO | PPV improves retinal oxygenation and is able to deal with the macular edema; it also allows the opening of the capsule strangulating the vein at the arteriovenous crossing |
Capsulectomy | The probe allows controlled opening of the capsule without leaving large floater/s behind; it also allows anterior vitrectomy, which is especially important in young children |
Cellophane maculopathy | Removal of the ILM is the only curative option |
Choroidal melanoma | PPV offers, in selected cases, long-term systemic prognosis that is not inferior to other treatment modalities while preserving vision without the risk of causing vision-destructive radiation retinopathy |
Coats’ disease | Complete vitrectomy with removal of preretinal membranes (and possibly draining the subretinal fluid) is an option in later stages or refractory cases |
CRVO | PPV improves retinal oxygenation and is able to deal with the macular edema; it also allows cannulating the major vessel for clog-opening drug infusion |
EMP | Removal of the scar (and for most surgeons of the ILM) is the only option that addresses the pathology itself, not simply its consequencesb |
Endophthalmitis | Not leaving pus (purulent vitreous) behind is the key to achieve the best possible prognosis |
Floaters/synchysis | If the patient is bothered by the mobile shadows the opacities cast on the retina, PPV has excellent prognosis at minimal riskc |
Glaucoma, ghost cell | Without clearing the reservoird, there is an almost infinite (re)supply of degenerated red blood cells |
Glaucoma, malignant | Removal of the vitreous creates space for the normal aqueous drainage pathway and prevents the aqueous from pushing the vitreous forward |
Hyphema (clotted) | It is rarely possible to remove the clot with forceps or simple aspiration; conversely, clot removal with the probe is possible even in phakic eyes, and the size of the clot is irrelevant |
IOL, luxated | Total or subtotal PPV must precede manipulations of the IOL, whether removal or repositioning is performed |
IOL, subluxated | Depending on the actual situation, capsulectomy, anterior vitrectomye, or true PPV may be necessary |
Iris-claw lensf implantation | As a minimum, judicious anterior vitrectomy is necessary |
Iris-IOL prosthesis implantation | As a minimum, judicious anterior vitrectomy is necessary |
Lens luxated into AC | As a minimum, vitreous removal from the AC and judicious anterior vitrectomy are necessary |
Lens luxated into vitreous/dropped nucleus | Total or subtotal PPV must be performed before the lens is removed via phacofragmentation or lensectomyg |
Lens subluxated | As a minimum, judicious anterior vitrectomy is necessary |
Lensectomy | The probe is used to remove the entire lensh |
Macular edema | Regardless of the etiology, the posterior hyaloid face must be detached and the ILMi should also be removed |
Macular hole | At least minimal vitrectomy is needed and the ILM is also removedj |
PDR | Complete vitrectomy is needed with removal of pre- and subretinal membranes |
Phacomatoses | Typically, PPV is employed to treat a secondary RD |
Prophylactic (e.g., high myopia) | To reduce the risk of RD, complete vitrectomy is performed, combined with lens removal (and possibly that of the lens capsules), and accompanied by judicious laser cerclage |
Pupilloplasty | Anterior vitrectomy is to be considered in the aphakic and occasionally the pseudophakic eye |
PVR | Complete vitrectomy is needed with removal of the pre- and subretinal membranes |
RD | Complete vitrectomy is recommended, possibly also ILM removal |
RD, central (high myopia), whether or not accompanied by a macular hole | As-complete-as-possible vitrectomy is necessary with peeling of the ILM in as large an area as possible |
RD, hemorrhagic | Complete vitrectomy with removal of the subretinal blood if it is, or threatening to become, submacular (see below); tPA may also have to be used |
RD, tractional | Complete vitrectomy is needed with removal of pre- and subretinal membranes |
Retinoschisis | Technically the vitrectomy can be very challenging and should thus be delayed until the macula is threatened; if PPV is necessary, it should be as complete as possible |
ROP | Vitrectomy is performed in the later stages and should be as complete as possible; the lens may be spared |
RPE transplantation | A complete vitrectomy is part of this complex procedure |
Silicone oil removal/exchange | The retina should always be very thoroughly examined to determine whether manipulations such as membrane peeling and/or retinectomy are needed; unless the oil was implanted for nontraditional uses such as a macular hole, there is always some risk of postoperative RD development |
Submacular hemorrhage | Complete vitrectomy with removal of the subretinal blood is necessary; it is crucial to do it early (see above) |
Suprachoroidal blood | If acute removal of the blood is neededk and the blood is still clotted, the probe is the only weapon the surgeon has to shave down the clot |
Toxocariasis | To remove the epiretinal scar; if a “collar button”l proliferation is present, the submacular part is usually left behind |
Trauma, contusion | Crucial to perform total vitrectomy |
Trauma, open globe | Crucial to perform total vitrectomy |
Uveitis | Total or subtotal vitrectomy is recommended, also ILM peeling if macular pathology such as edema is already present or expected |
VH | Less than subtotal vitrectomy is not recommended |
Vitreous prolapse into the AC | Complete removal of the vitreous from the AC, including from the surface of the iris, or at least severing its connections to the posterior vitreous |
VMTS | Subtotal or total vitrectomy to eliminate the traction not only centrally but also in the periphery and ILM peeling are recommended |
Not occur at all.
Have a smaller risk of occurring.
Have a more benign course.
Would resolve faster.
Have a slower progression.
Stop progressing.
Would not recur or have a lower risk of recurrence.
The absence of the vitreous gel in the vitreous cavity has further implications.
The oxygen tension in the posterior segment significantly increases once no gel is present. This is especially beneficial for patients with vein occlusion, diabetes, or poor circulation for other reasons – but makes cataract development a side effect, not a complication.1
The clearance of substances from the vitreous cavity increases after PPV. This is advantageous in vitreous (re)bleeding but disadvantageous if intravitreal medications are used.
27.2 How Much Vitreous to Remove?
Just as important as the question of how to remove the vitreous is how much to remove. The range stretches from “nonvitrectomizing” to “complete” PPV2 (see Fig. 27.1 and Table 27.2).
Fig. 27.1
Schematic representation of classifying the extent of vitreous removal. This is a personal, somewhat arbitrary, and not objectively measurable/verifiable attempt at distinction. The numbers represent percentages: 0%, nonvitrectomizing; 10%, minimal; 30%, core; 50%, semitotal; 80%, subtotal; 100%, total or complete (see Table 27.2 for more details)
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