Vitreoretinal Surgeries

Indications & Pre-op Eval - Setting the Stage

• Indications:
  • Retinal Detachment (RD): Rhegmatogenous, Tractional
  • Vitreous Hemorrhage (non-clearing)
  • Macular Hole, Epiretinal Membrane (ERM)
  • Proliferative Diabetic Retinopathy (PDR) complications (TRD, VH)
  • Endophthalmitis, Intraocular Foreign Body (IOFB)
• Pre-op Evaluation:
  • History (systemic/ocular), Visual Acuity (VA), IOP
  • Slit-lamp & dilated fundus exam (indirect ophthalmoscopy)
  • Key Investigations:
    • B-scan: Essential for opaque media (VH, cataract)
    • OCT: Macular details (MH, ERM)
  • Systemic fitness, consent (risks/benefits)

  ⭐ B-scan ultrasonography is indispensable for diagnosing RD and planning surgery when media opacity obscures the fundus view.

Core Surgical Steps - Eye's Inner Workings

• Setup: Anesthesia (Peribulbar/GA). Conjunctival peritomy.
• Ports (Sclerotomies): 3 ports via pars plana.
  • Sizes: 23G, 25G, 27G.
  • Placement: Infusion (maintains IOP), Light pipe (illumination), Vitrector (cuts/aspirates vitreous).
  • Distance: 3.5-4 mm (phakic/pseudophakic), 3-3.5 mm (aphakic) from limbus.
• Vitrectomy: Core (central) & Peripheral (base, often with scleral depression).
• Pathology Management: Membrane peeling, endolaser photocoagulation.
• Tamponade: Fluid-Air Exchange (FAX) → Gas ($SF_6$, $C_3F_8$) / Silicone Oil.
• Closure: Sutureless (small gauge) or sutured ports.

⭐ Silicone oil provides longer tamponade than gas; preferred for inferior breaks or Proliferative Vitreoretinopathy (PVR).

Intraocular Tamponades - Space Fillers Supreme

• Function: Internal retinal support, appose retina to RPE.
• Types:
  • Gases: Absorb spontaneously.
    • Air (shortest acting, ~3 days).
    • Expansile: SF6 (~2 wks), C2F6 (~4 wks), C3F8 (~8 wks).
    • 📌 Mnemonic (Expansion/Duration↑): Some Fine Carbon lasts Long (SF6 < C2F6 < C3F8 < Silicone Oil).
    • Non-expansile conc: SF6 20%, C3F8 14%.
    • Caution: No air travel/N2O with expansile gas.
  • Silicone Oil: Long-term; optically clear.
    • Viscosities: 1000, 5000 cS.
    • Needs removal. Complications: Emulsification, keratopathy, ↑IOP.

⭐ Gases cause initial myopic shift (bubble acts as minus lens); Silicone oil causes hyperopic shift (acts as plus lens).

Post-op & Complications - Aftercare & Alerts

• Immediate Aftercare
  • Strict head positioning (e.g., face-down with gas).
  • Meds: Topical steroids, antibiotics, cycloplegics, analgesics.
  • Monitor IOP (target <21 mmHg); report significant ↑.
  • Activity: Avoid strenuous tasks, head jerks, rubbing.
• Critical Alerts (Seek Urgent Review)
  • Sudden, severe, or increasing pain.
  • Marked ↓vision, new floaters/flashes, field defects (curtain).
  • Signs of infection: ↑Redness, discharge, lid swelling.
• Key Complications
  • Early: ↑IOP, corneal edema, uveitis, vitreous hemorrhage.
  • Late: Endophthalmitis (⚠️ emergency!), recurrent RD, PVR, CME, ERM, cataract.

⭐ Staphylococcus epidermidis is the most frequent cause of post-vitrectomy endophthalmitis.

Specific VR Surgeries - Spotlight Procedures

• Pars Plana Vitrectomy (PPV):
  • Uses: RD, VH, ERM, MH, Endophthalmitis.
  • Core: Vitreous removal, address pathology, tamponade (gas/oil).
• Scleral Buckling (SB):
  • For RRD: esp. phakic, young, inferior breaks. Supports break.
• Pneumatic Retinopexy (PR):
  • Select RRDs: Superior breaks (e.g., 10-2 o'clock), clear media. Gas + laser/cryo.
• Macular Hole Surgery:
  • PPV + ILM peel + gas. High success.
  • 
• ERM Peeling: PPV to remove macular scar tissue.

⭐ ILM peeling in macular hole surgery boosts anatomical closure (>90%) & vision.

High‑Yield Points - ⚡ Biggest Takeaways

• Pars Plana Vitrectomy (PPV): Mainstay for posterior segment issues like RD, vitreous hemorrhage.
• PPV also treats macular holes, epiretinal membranes, and removes intraocular foreign bodies (IOFBs).
• Tamponade: Silicone oil or gases (SF6, C3F8); specific post-op positioning is critical with gas.
• Endolaser photocoagulation seals retinal breaks and is used for panretinal photocoagulation (PRP).
• Scleral buckling: External procedure, often for phakic RDs with peripheral breaks.
• Commonest PPV complication: iatrogenic cataract; others: raised IOP, endophthalmitis.