Sunday, October 02, 2005

Chapter 5 - Managing Surgical Complications

Vitreous Prolapse

Causes of Vitreous Prolapse

  • Capsular tear

    • Anterior tear extending posteriorly - most common cause
    • Posterior tear - secondary to phaco too deep, I/A, or another instrument
    • Pre-existing condition, e.g.: posterior polar cataract, iatrogenic from prior pars plana vitrectomy, penetrating lens trauma

  • Zonular dialysis

    • Iatrogenic from forceful rotation or pulling on the capsule
    • Pre-existing condition, e.g.: trauma, pseudoexfoliation, Marfan's

Signs of Vitreous Prolapse

  • Denial
  • Chamber deepens
  • Pupil widens
  • Lens material no longer centered
  • Particles no longer come to phaco or I/A
  • Lens no longer rotates freely

Basic Principles of Vitrectomy

Vitreous Presenting early in case - while most of crystalline lens is in eye

  • Strongly consider converting to ECCE

    • If topical, do subtenons injection for additional anesthesia [view video ].
    • Close temporal incision with 10-0 nylon suture and follow ECCE steps except use lens loop
    • Have Wescott scissors ready when looping out lens to cut vitreous
    • Close with 3-4 Vicryl safety sutures

  • Sometimes you can proceed with Phaco very carefully

    • Seal off capsular hole with liberal use of Viscoat (cohesive OVD will not work)
    • Keep phaco occluded in the lens as much as possible
    • Consider using sheets glide to seal off hole -- trap nucleus in AC
    • Work with one or two large pieces (rather than chopping into many small bits which may fall into the posterior-pole of the eye)

  • Following removal of residual nucleus

    • Anterior vitrectomy, perform Weck cell vitrectomy (i.e., using a Weck cell sponge to pull vitreous from wound and cutting vitreous with Wescott scissors. Remember that tugging on the vitreous also applies forces that are tugging on the retina where the vitreous is attached.)
    • Dry removal of residual cortical material with syringe on 27 gauge cannula
    • Use J-cannula if needed for subincisional material
    • Consider staining with Kenalog
    • Place IOL if possible in sulcus or AC IOL (if AC, don't forget peripheral iridotomy to prevent pupil block glaucoma)
    • Use Miochol to bring pupil down, which seats sulcus IOL. Also, peaked pupil helps to detect vitreous that is coming forward into the anterior chamber.

Vitreous Presenting Mid-Case - while removing cortical material

  • Most common time vitreous presents
  • Place viscoat in area of tear or dialysis before removing instruments
  • Anterior vitrectomy

    • Split into an irrigating cannula (e.g. 23 guage cortex extractor) and the vitreous cutter (without sleeve)
    • Suture wound and use two paracenteses one for the cutter and one for irrigating cannula
    • Irrigate high and cut / suck low – creates a pressure gradient to push the V back . [view video]
    • Settings: low vacuum in the 100 range, low bottle height in the 50 range, max cut rate
    • Try to get some of the residual cortical material

  • Following anterior vitrectomy

    • Dry removal of residual cortical material with syringe on 27 gauge cannula
    • Use J-cannula if needed for subincisional material
    • Consider staining with kenalog (see below)
    • Place IOL if possible in sulcus or AC (if AC don't forget peripheral iridotomy) . [view video]
    • Miochol to bring pupil down

How to deal with Vitreous Presenting late in the case - while placing IOL

  • Stabilize the IOL by placing one haptic out of the wound or in the AC
  • Perform anterior vitrectomy as described above - attempt to get the cutter below the IOL
  • Place both haptics in the sulcus if possible (cannot use the Alcon SA60 lens in sulcus)
  • Use Weck cell sponge to ensure wound is clear of vitreous
  • Consider stain (see below)
  • Use Miochol in the anterior chamber to check pupil

Staining the Vitreous with Kenalog
[view video]

  • Great idea by Scott Burk at Cincinnati Eye
  • Prepare Kenalog by removing preservative and diluting 10:1

Modified Method (of Burk):

  • TB syringe to with 0.2 ml of well shaken Kenalog (40 mg/ml)
  • Remove the needle and replace with a 5 (or 22) micron syringe filter (Sherwood Medical)
  • Force the suspension through the filter and discard the preservative filled vehicle
  • The Kenalog will be trapped on the syringe side of the filter
  • Transfer the filter to a 5 ml syringe filled with balanced salt solution (BSS)
  • Gently force the BSS through the filter to further rinse out preservative
  • Repeat rinsing a few times
  • Place a 22 gauge needle on the distal end of the filter
  • Draw 2 ml of BSS into the syringe through the filter to resuspend the Kenalog
  • The Kenalog (now without preservative) will stain vitreous strands white



Post a Comment

Links to this post:

Create a Link

<< Home