Advances in Vitreoretinal Surgery August 24, 2012



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Advances in Vitreoretinal Surgery

August 24, 2012

Jeremiah Brown, Jr., MS, MD

Brown Retina Institute

17319 IH35N, Suite 303

Schertz, TX 78154


Disclosures
I will be discussing the off label use of medications.
I lecture to physicians on behalf of Genentech and am a member of the speaker’s bureau.
Posterior Vitreous Detachment

1. Posterior vitreous separates from the retina and collapses anteriorly toward the vitreous base

2. Vitreous base straddles the ora serrata, 2mm anteriorly and 2-4 mm posteriorly.

3. Weiss ring: attachment of the vitreous at the optic nerve head

4. Traction at the vitreous attachment near the vitreous base or at the border of a lattice lesion may result in a retinal horseshoe tear
Posterior Vitreous Detachment


  1. Prevalence of PVD increases with age.

  2. Occurs earlier in myopia, after cataract surgery, open posterior capsule

  3. The prevalence of PVD is approximately 70% in persons over 70 years of age.

  4. PVD without vitreous hemorrhage has an incidence of retinal tear of only 2-4%.

Posterior Vitreous Detachment



  1. PVD with vitreous hemorrhage has an incidence of retinal tear of 70%.

  2. Symptoms present:

    1. days to weeks- see urgently

    2. weeks to months- see within 1 week

  3. If vitreous hemorrhage obscures view of fundus, ultrasound must be performed to rule out retinal detachment (RD).

  4. Bedrest, bilateral patching and head elevation may aid in clearing the visual axis and superior periphery.

Retinal Breaks

1. Retinal hole:

a) round atrophic break

2. Retinal tear:

a) break related to vitreoretinal traction

b) usually due to posterior vitreous detachment
Traumatic Retinal Breaks

1. Occur with open or closed ocular trauma

2. 75-86% of traumatic detachments due to blunt trauma

3. Both coup and contra-coup forces may cause retinal breaks.

4. Retinal dialyses account for 76% of retinal breaks after blunt trauma

5. Traumatic dialyses most commonly occur inferotemporally and superonasally

6. Late fibrocellular proliferation along the tract of penetrating trauma may result in a retinal break.

7. Traumatic retinal detachment frequently develops days or weeks following trauma when the vitreous overlying a traumatic break liquifies.


Asymptomatic Retinal Breaks

1. 5-6% of autopsy eyes and clinical studies, more common in myopes

a) round holes 76%

b) round hole with operculum 13%

c) horseshoe tears 10%

2. Progression to retinal detachment infrequent

3. If fellow eye has history of RD, 30% progress to RD

4. Retinal dialyses often progress


Lattice Degeneration

1. 8-10% of the population

2. 0.3-0.5% of patients with lattice degeneration develop retinal detachment

3. However, 20-40% of detachments are related to lattice

Prophylactic Treatment Of Retinal Breaks


  1. Acute, symptomatic retinal tears should be treated

2. Observe asymptomatic atrophic holes
Rhegmatogenous Retinal Detachment (RRD)

1. Types of retinal detachment

a) Rhegmatogenous rhegma= rent or fissure

b) Tractional diabetic retinopathy, inflammatory

c) Exudative tumors, inflammatory

2. A retinal tear can be identified in 97% of rhegmatogenous retinal detachments.

3. History of floaters and photopsia can be elicited in 50% of patients with RRD.

4. Other findings in RRD include:

a) “tobacco dusting” in the vitreous

b) lower IOP in the involved eye

c) corrugated appearance of detached retina

d) presence of fixed folds


Rhegmatogenous Retinal Detachment

1. Principles of retinal detachment surgery

a) identify all retinal breaks

b) close all retinal breaks

c) relieve vitreoretinal traction

d) create chorioretinal adhesion around the breaks

2. Overall reattachment rate in RRD surgery is > 90%
Method of Repair

Factors


1. Size and location of breaks

2. Presence of other pathology (e.g. lattice, hemorrhage, PVR)

3. Presence and stage of PVR

4. General health of patient


Timing of Repair

  1. Acute, macula attached RD: within 1-2 days

  2. Acute, macula detached RD: as soon as possible

  3. Chronic macula detached RD: not emergent

Proliferative Vitreoretinopathy

1. PVR is the principle cause of failure in retinal detachment surgery

2. Development of PVR is associated with:

a) access to retinal surface by liberated RPE cells (large retinal break/cryopexy)

b) presence of blood in vitreous, growth factors, fibronectin

c) presence of vitreous

d) inflammation


Retina Reattachment Techniques

1. Pneumatic retinopexy

2. Scleral buckle

3. Vitrectomy

4. Chorioretinal adhesion by cryopexy, laser retinopexy, or diathermy
Preoperative Management

1. Explanation of methods of repair

2. Bed rest for macular threatening and giant retinal tears

3. NPO for all but outpatient pneumatic retinopexy

4. Preoperative laboratory studies indicated by age and health status

5. Stop anticoagulants if possible


Laser / Cryopexy Demarcation

1. Small peripheral retinal detachments

2. Adequate demarcation important

3. Follow closely until good demarcation line present

4. Caution patient about symptoms of progression
Pneumatic Retinopexy

1. Ideal candidate

a) breaks in superior 8 clock hours

b) all breaks within 1 clock hour

c) no other retinal pathology

d) no PVR, vitreous hemorrhage

e) phakic

2. Procedure

a) retrobulbar or subconjunctival anesthesia

b) apply cryopexy to retinal breaks (or laser once retina is flat)

c) irrigate conjunctiva with betadyne

d) lid speculum

e) position patient

f) inject gas C3F8 or SF6

g) withdraw needle; cotton tipped applicator placed over exit site reduces gas escape

h) monitor central retinal artery perfusion

i) check IOP in 1 hour

j) instruct patient in positioning, steamroller technique

k) follow-up next day

l) fluid should decrease each day

m) strict positioning is key to success
Pneumatic Retinopexy

3. Complications

a) elevated IOP

b) vitreous hemorrhage

c) vitreous incarceration

d) subretinal gas

e) new or enlarged retinal tear

f) infection

g) cataract
Scleral Buckle Procedure

1. First performed in US in 1951

2. Relieves vitreous traction

3. Procedure

a) anesthesia: retrobulbar, MAC, GETA

b) conjunctival peritomy

c) isolate rectus muscles on traction sutures

d) inspect sclera

e) localize and mark breaks

f) apply cryopexy to breaks

g) choose an exoplant which fits the tears

h) preplace sutures

i) drain subretinal fluid

j) tighten buckle

k) examine retina for central retinal artery perfusion and position of breaks

l) closure


Scleral Buckle Procedure
Complications

a) disinsertion of rectus muscle

b) globe perforation

c) hemorrhage- suprachoroidal, subretinal, vitreous

d) retina or vitreous incarceration in drainage site

e) elevated intraocular pressure

f) myopia, astigmatism

g) diplopia

h) infection

i) buckle extrusion

j) erosion of buckle into eye
Pneumatic Retinopexy vs. Scleral Buckle Procedure

a) Pneumatic retinopexy study

b) For the ideal patient
PR SB

Initial reattachment 73% 82%

Final reattachment 99% 98%

Final visual acuity 20/25 20/30


Visual Prognosis

1. Macula-on detachment

87% achieve 20/50 or better

2. Macula-off detachment

37% achieve 20/50 or better

3. Visual prognosis improved if macula off less than one week.

4. Visual result after pneumatic retinopexy is better than that achieved with scleral buckling surgery
Bottom Line: Scleral buckle procedure is performed much less frequently now than in the past.
Pars Plana Vitrectomy

1. Surgical removal of the vitreous

2. Removes traction from the retina directly

3. Procedure

a) perform steps for scleral buckling if combining both procedures

b) place trocar canulas

c) wide field viewing

d) core vitrectomy

e) peel any membranes present

f) flatten the retina with air, PFO

i. drain through the break

ii. drainage retinotomy

g) endolaser

h) long acting gas tamponade C3F8 or SF6, silicone oil

i) close sclerotomies, conjunctiva
Pars Plana Vitrectomy for Retinal Detachment

Indications

a) proliferative vitreoretinopathy

b) giant retinal tear

c) vitreous hemorrhage obscuring tear

d) posterior breaks

e) intraocular foreign body

f) uveitis

g) tractional component

h) pseudophakic

i) any rhegmatogenous retinal detachment
Vitrectomy Complications

a) cataract

b) iatrogenic retinal breaks

c) elevated intraocular pressure

d) suprachoroidal, retinal, vitreous hemorrhage
Recurrent Retinal Detachment

a) new breaks

b) missed breaks

c) inadequate support by buckle

d) proliferative vitreoretinopathy
Vitrectomy in Diabetic Retinopathy

Indications

1. Non-clearing vitreous hemorrhage

2. Retinal detachment- tractional, rhegmatogenous

3. Premacular fibrosis

4. Diabetic macular edema with macular traction


Goals of Vitrectomy

1. Clear the vitreous cavity

2. Apply endolaser to induce regression of neovascularization

3. Relieve vitreoretinal traction

4. Reduce retinal ischemia
Technique

1. Vitrectomy to remove vitreous and hemorrhage

2. Silicone tipped cannula to remove subhyaloid hemorrhage

3. Segmentation- vitrectomy instrument or scissor can be used to isolate islands of adhesion

4. Delamination- retinal forceps with horizontally oriented scissors or the vitrectomy instrument can be used to achieve more complete dissection

5. Scleral buckle- avoid

6. Endolaser

7. Gas or silicone oil

8. Consider preoperative Avastin to decrease the activity of the neovascularization resulting in less intraoperative bleeding

Complications

1. Elevated intraocular pressure

2. Corneal epithelial defects, edema

3. Cataract

4. Vitreous hemorrhage

5. Fibrin membranes in the anterior chamber

6. Anterior segment neovascularization


Macular Hole

A. Demography

1. Women

2. Sixth - Eighth decades

3. Bilateral 25 - 30%

4. Occurs in 0.5% to 1% of the population

B. Pathology

1. Anterior-posterior vitreoretinal traction from partial PVD

2. Tangential surface traction

C. Macular Hole - Stages

1. Stage I - yellow spot (A) or yellow ring (B)

2. Stage II- Full thickness “can opener” like break

3. Stage III- Full thickness retinal hole often associated with drusen and cuff of subretinal fluid

4. Stage IV- Hole with operculum and PVD


Vitrectomy for Macular Hole

1. Relieve vitreoretinal traction

2. Tamponade

3. Technique



    1. engage the posterior vitreous with a soft tipped cannula or vitreous cutter

    2. peel vitreous cortex from retinal surface

    3. triamcinolone, ICG or Vision blue to identify ILM

    4. peel epiretinal membranes

    5. peel internal limiting membrane

    6. air/fluid exchange

    7. long acting gas SF6 or C3F8

Vitrectomy for Macular Hole

D. Visual prognosis

1. 93% closed with one operation

2. 87% 20/40 or better

dependent upon initial visual acuity


Epiretinal Membrane

A. Pathology

1. Glial proliferation through a defect in the internal limiting membrane

2. Usually preceded by posterior vitreous detachment

B. Visual loss

1. Contraction of epiretinal membrane with leakage from retinal capillaries

2. Elevation of retina off the RPE

3. Visual decline occurs over weeks to months then stabilizes

4. Threshold for operating varies depending on impact of acuity loss and surgeon preference
Pars Plana Vitrectomy

Technique

1. Core vitrectomy

2. Directly grasp membrane with forceps or MVR blade is used to incise the membrane

3. Retinal pick can be inserted into the opening to elevate membrane from surface of retina

3. Forceps are used to engage the edge and peel off the surface of the retina

4. Gas tamponade not necessary
Visual Prognosis

1. Macular edema and retinal distortion invariably improve

2. 50% improve 2 lines or more

3. 50% 20/80 or better

4. 40% 20/40 or better

5. Dependent upon initial visual acuity


23 and 25 gauge Transconjunctival Surgery

Bausch & Lomb

Dutch Ophthalmic Research Company

Alcon


Advantages

  1. Smaller wounds

  2. Preserves the conjunctiva

  3. Faster visual recovery

  4. Greater patient comfort

Potential disadvantages

Hypotony

Greater risk of infection

Higher rate of retinal detachment (controversial)
Eliminating Potential Disadvantages

Hypotony


  1. Proper wound construction

  2. Place a stitch when necessary

  3. Do not put excessive torque on the wound

Infection

  1. Displace conjunctiva from sclerotomy

  2. Povidone iodine prep

  3. Preoperative antibiotic drops

  4. Complete vitrectomy surrounding sclerotomy

  5. Plug the canulas before removal

Retinal detachment

  1. Proper wound construction

  2. Remove vitreous from the sclerotomy site

  3. Avoid rapid and frequent instrument exchanges

  4. Examine the peripheral retina after completing vitrectomy

  5. Plug the canulas before removal

Patient Care Information

A. Detailed discussion of disease process and prognosis preoperatively.

B. Surgical options and option of observation discussed with techniques, risks and benefits.

C. Visual prognosis following surgery discussed.

D. Patients’ misconceptions laid to rest


Patient Care Information

1. The eye is not removed during surgery.

2. The eye cannot be transplanted, only the cornea.

3. Unlike in the movies, dramatic improvement in vision seldom occurs on the day after retinal reattachment surgery.

4. Most retinal detachments occur spontaneously; the patient is not at fault.

5. You will not feel or see the silicone implant that has been sutured to the eye.


Post-operative Instructions

1. Do not allow water to get into eye for 2-3 days.

2. Ice packs may be placed over the lids two to four times daily.

3. Do not strain to have a bowel movement. Inform your doctor if you need a laxative.

4. Dilating, anti-inflammatory, and antibiotic drops will be instilled 2 to 4 times daily.

5. Specific instruction on use of eye drops.

6. You may wear your glasses. You may watch TV unless restricted by positioning. A television may be placed on the floor. Books may be read in your lap.

7. Vary your position frequently to prevent stiffness and boredom.

8. Gently clean your eyelids twice a day. Use a clean, wet washcloth. Never use the same washcloth twice. Avoid pressure on the eye.

9. For your comfort you may (particularly for scleral buckle patients):

- wear an eye pad to absorb excess tears.

- use ice packs over your operated eye to reduce swelling and discomfort.

- wear dark glasses or an eye pad. You may be sensitive to light because of pupil dilation.

10. You may:

- take a shower or tub bath; shampoo

- do light housework

- take walks and walk up and down stairs

11. Until permitted by your physician, do not

- return to school or work

- strain or lift over 20 pounds

- engage in any strenuous activity

- do garden or yard work

- drive a car

12. Instructions on positioning

13. Call for

a) increasing redness

b) increasing lid swelling

c) pain unrelieved by Tylenol



d) decreased vision

e) thick discharge

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