What is Pars Plana Vitrectomy (PPV) for retinal detachment repair?

Pars Plana Vitrectomy (PPV) for Retinal Detachment Repair

Pars plana vitrectomy (PPV) is a surgical procedure that removes the vitreous gel from the eye to repair retinal detachment, achieving anatomic success rates of 88-96% with comparable outcomes to scleral buckling, and is particularly effective for pseudophakic retinal detachments and cases with complex or unseen breaks. 1, 2, 3

Surgical Technique and Objectives

The primary anatomic goal of PPV is to separate the posterior cortical hyaloid from the retinal surface of the macula. 1 The procedure involves:

• Core vitrectomy with removal of the vitreous gel to eliminate vitreoretinal traction 1
• Induction of posterior vitreous detachment (PVD) if not already present, often using triamcinolone acetonide to visualize the posterior vitreous 1
• Peripheral retinal examination for breaks or tears performed intraoperatively prior to air-fluid exchange to minimize postoperative retinal detachment risk 1
• Endolaser photocoagulation applied around retinal breaks to create chorioretinal adhesion 3
• Fluid-gas exchange or silicone oil tamponade to maintain retinal apposition during healing 2, 3

Anatomic and Visual Outcomes

PPV demonstrates excellent success rates across different patient populations:

• Overall single-surgery reattachment rate: 88-94% in complex rhegmatogenous retinal detachment 2
• Final reattachment rate: 96-97% after additional procedures if needed 2, 3
• Macula-attached detachments: 91% single-surgery success 3
• Macula-detached detachments: 86% single-surgery success 3
• Median visual acuity improvement from 20/300 preoperatively to 20/40 postoperatively in pseudophakic eyes 3

A Cochrane systematic review found low to very low certainty evidence indicating little or no difference between pars plana vitrectomy and scleral buckling in anatomical and visual acuity outcomes. 1

Indications and Patient Selection

PPV is particularly advantageous in specific clinical scenarios:

• Pseudophakic retinal detachments where lens removal is not a concern 4, 3
• Complex or multiple retinal breaks at different distances from the ora serrata 5
• Posterior retinal breaks difficult to access with scleral buckling 5
• Media opacities obscuring retinal breaks where visualization is compromised 5
• Dense vitreous hemorrhage preventing adequate fundus examination, where early vitrectomy (within 7 days) reduces risk of vision loss from macula-involving retinal detachment 1

Critical Intraoperative Considerations

Internal Limiting Membrane (ILM) Management

While the evidence primarily addresses macular hole surgery, ILM peeling during vitrectomy significantly reduces the likelihood of hole reopening but without demonstrable improvement in postoperative visual acuity. 1 The ILM may act as a scaffold for cellular proliferation causing persistent vitreoretinal traction. 1

Tamponade Selection

• Gas tamponade versus silicone oil shows statistically significant differences in redetachment rates in phakic eyes (p = 0.001), with gas performing better 2
• Reattachment rates are similar regardless of tamponade choice in pseudophakic eyes 2
• Postoperative positioning is critical to tamponade the retinal breaks and minimize cataract risk in phakic eyes 1

Complications and Risk Management

Common Complications

• Cataract formation is the most significant concern in phakic eyes, though this is not applicable in pseudophakic patients 5, 4
• Iatrogenic retinal breaks may develop during PVD creation, requiring careful intraoperative peripheral examination 1
• Macular pucker requiring surgery: 6% 3
• Cystoid macular edema: 17% 3
• Full-thickness macular holes: 2% 3
• Elevated intraocular pressure (IOP) postoperatively, particularly with gas tamponade 1

Critical Pitfalls to Avoid

• Failure to examine the peripheral retina intraoperatively before air-fluid exchange increases retinal detachment risk 1
• Inadequate patient counseling about postoperative positioning can compromise surgical success 1
• Use of nitrous oxide during general anesthesia within the last 10 minutes of air-fluid exchange results in unpredictable gas fill 1
• Travel to altitudes above 2000 feet postoperatively can cause dangerous IOP elevation 1
• Missing scheduled postoperative visits prevents early detection of IOP elevation, which can cause permanent vision loss especially in glaucoma patients 1

PPV Alone vs. Combined with Phacoemulsification

For phakic patients, the decision between PPV alone (PPVa) versus combined with phacoemulsification (PPVc) involves specific trade-offs: 6

• PPVc enhances peripheral retina visualization and vitreous base management but prolongs surgical time 6
• PPVc causes iatrogenic loss of accommodation in younger patients and risks postoperative anisometropia with unexpected refractive results 6
• PPVa requires superior technical skills to minimize lens damage and accelerates cataract development 6
• Anatomic RRD repair rates are generally comparable between PPVa and PPVc 6
• PPVc has fewer intraoperative complications but more postoperative complications 6
• Macula-off RRD treated with PPVc often results in undesirable myopic refractive error 6
• Refractive error remains essentially unchanged with PPVa (mean change -0.15 diopter) 3

Postoperative Management

Patients require close monitoring for:

• IOP elevation, particularly in the first postoperative period with gas tamponade 1
• Compliance with positioning instructions, typically face-down or specific head positioning for 1-2 weeks 1
• New symptoms including increased floaters, visual field loss, or decreased acuity requiring prompt re-evaluation 7
• Cataract progression in phakic eyes over subsequent months 5, 4

Prognostic Factors

Anatomic success is not significantly affected by:

• Lens status (phakic vs. pseudophakic): 94.9% vs. 93.1% reattachment rates 2
• Preoperative proliferative vitreoretinopathy (PVR) ≥ C1: 92.6% vs. 91.1% without PVR 2
• Axial length (≤24 mm vs. >24 mm): similar reattachment rates 2
• Anterior chamber vs. posterior chamber IOL: 91% vs. 88% reattachment rates 3