3.
The annual incidence is approximately 10: 10 000;
Retinal detachment associated with premature vitreous detachment;
Particularly important predisposing entities include:
High myopia (> 6.0 D);
Pseudophakia and aphakia (cataract surgery has been performed on only approximately
3% general population);
Blunt and penetrating ocular trauma ( severe ocular trauma is believed to be responsible for
10 – 15 % of retinal detachments);
Cytomegalovirus retinitis ( breaks are development at sites of prior inflammation).
15% of symptomatic PVD have tears
Asymptomatic breaks occur in 7% of patients over the age of 40
Lattice is present in 8% of general population and 30% of RD have lattice related tears
4.
Retinal breaks- around retinal scars, cystic tufts, meridional
complexes, lattice degeneration.
Breaks at the posterior margin of the vitreous base,typically occur in the
presence of posterior vitreous detachment -PVD.
6.
The forces tending to maintain retinal attachment are:
1. The hydraulic force from the intraocular pressure (IOP);
2. The increased oncotic pressure within the choroid, relative to the subretinal
space;
3. The RPE pump, which transports ions and fluid from the subretinal space into
the choriocapillaris.
The forces promote movement of liquid vitreous through the retinal break into
the subretinal space:
1. Vitreous traction;
2. Gravity, which may increase the patency of a superior
retinal break and allow more fluid to pass through;
3. Eye movements, which may exacerbate vitreoretinal traction
and increase the formation of RRD.
7. Total or superior
detachment
In 93% original
break placed…
Supero-temporal
or supero- nasal
detachment
In 98% original
break placed…
inferior
detachment
In 95% original
break placed…
8. Preoperative evaluation;
1. Complete medical history;
2. Family history;
3. Ocular history;
4. Complete eye exsamination.
Identification of all retinal breaks;
Complate sealing of all retinal breaks;
Relif of vitreoretinal traction.
10. Scleral buckling works through at least three mechanisms:
1. The procedure directly offsets antero-pesterior vitreous traction along the
surface of the buckle;
2. The buckle displase the retinal break centrally, where the break becomes
tamponaded by cortical vitreous, preventing further flow of fluid
through the break;
3. The buckle displaces subretinal fluid away from the break and alters the
shape of eyewall, thus reducing the effects of the intraocular fluid
currents.
11.
Cryotherapy
Diathermy
Laser treatment with the argon or the diode laser
Complications of cruopexy
Excessive treatment formation new breaks;
May generate breakdown of the blood-ocular battier ( leading to prolonged postoperative
inflammation and possibly increasing the risk of postoperative PVR) ;
Scleral perforation.
12. 1.Silicone sponge
2.Solid silicone rubber :
Bands;
Straight strips;
Symmetric and asymmetric tires.
Ecircling exoplant use in the following cases:
Multiple breaks;
Aphakic or pseudophakic eyes;
High myopia;
Extensive areas of lattice degeneration;
PVR
Giant tears
Eyes with very thin sclera.
Segmental circumferential buckles are indicated in closely spaced retinal breaks without the presence
of other retinal pathology.
Radial exoplants are preferred:
Large horseshoe tears;
Relatively posterior tears.
These elements are affixed to the episcleral surface with 5.0 polyester or nylon
or passing the elements through small lamellar scleral tunnels.
14.
Dislocation of buckling elements;
Scleral perforation;
Anisometropia- encircling elements may induce an average of approximately 2D of
myopia;
Strabismus;
Vortex veins could be compressed, possibly leading to choroidal detachment and IOP
elevation.
15. The most popular alternative technique to routine scleral buckling is pneumatic
retinopexy.
Intravitreal injection of an expansile gas bubble;
Cryopexy or laser photocoagulation of the break;
Appropriate postoperative head positioning.
Indications:
The single break in the superior 6 clock hours;
Multiple breaks –spaced closely together (preferably within 1-2 cluck hours);
Phakic and pseudophakic patients, if the view of the peripheral retina is adequate.
Contraindications:
Break larger than one clock-hour;
Multiple breaks extending more than three clock hours;
Breaks located in the inferior four clock-hours of the eye;
Significant traction on the retinal tears;
Patients who are unable to maintain adequate position;
Advanced glaucoma;
Cloudy media which prevent identification and tretment of the breaks.
16. Advantages:
Shorter time of surgery;
Less inflammation;
Less cost to the patient;
General anesthesia is not required.
Complications:
High –intraocular pressure may develop while introducing the gas into the intraocular cavity;
Gas – bubble may be pulling on the vitreous and retina which may result in bleeding or a retinal tear 15 %
The subretinal fluid may shift to the macular area;
Injection of gas into the space of petit,it breaks the anterior hyaloid and enters the vitreous cavity;
Small gas bubbles in the subretinal space;
Cataract formation;
Endoftalmitis;
PVR;
Reopening of retinal breaks .
19.
Sulfur hexafluoride- SF6 -- doubles its size in 36 hours, last about 10-14 days;
Perfluoropropane- C3 F8 -- quadruples it in 36 hours , last about 55-65 days.
A
0.3 ml gas- bubble covers more than 450 of the area of the retina
A 1.2 ml bubble to cover 80 to 900
In most cases a gas bubble volume of 1 ml, which requires an injection of 0.5 ml of pure SF6, is enough.
The area of the breaks should be covered by the bubble for at least 5 days.
The correct head position should be maintained for about 16 hours a day.
The subretinal fluid will be absorbed within approximately 24 hours.
Retinal reattachment has been achieved in 80-84 % .
With subsequent scleral buckling , the retina has been reattached in 98 % of the cases.
20.
The Lincoff balloon is another alternative to create a temporal buckling effect.it was
described by Harvey Lincoff in 1979. this is made of siliconized latex,at the end of a soft
plastic tube,are introduced in the subconjunctival space,the subretinal fluid absorbs
through the retinal pigment epithelium.the balloon inflated with 0.5 ml of sterile
water,when it lies derectly beneath the break this usually requires an additional 0.75 to 1.0
ml of water.after 7 days, the balloon is completely deflated and withdrawn under topical
anesthesia.
Indications:
Small retinal tears located superiorly with little amount of subretinal fluid;
Multiple breaks clustered within one clock hour;
Tears located 6 mm at the equator,not too posterior, have no PVR.
Reattachment of rhe retina has been reported in 64 % to 96 % of
cases, with the balloon tecgnique alone.
21. This works best with small,localized, peripheral detachments and occasionally
with retinal dialyses;
This technique may be useful in patients who have severe medical problems;
In situations where access to an operating room is limited.
22. The surgical technique consists in performing a pars plana vitrectomy.after core
vitrectomy, emphasis is placed on removing vitreous adherent to the margin of the retinal
breaks. Once the vitrectomy has been completed, additional heavy fluid (perfiorocarbon
liquids) is injected to flatten the retina.the subretinal fluid will be pushed through the
retinal break,when the heavy fluid is naer the posterior edge of the tears, an extrusion
cannula is placed in the break and a total fluid-gas exchange is performed, which
reattaches the retina.
Alternatives for draining the subretinal fluid are:
The passage of an extendable silicon extrusion catheter through a retinal break;
Transcleral drainage;
Making a posterior or anterior retinotomy.
Once the retinal is flat ,retinal breaks are treated with endolaserphotocoagulation or
external cryopexy.
23.
Sulfur hexafluoride- SF6 . The effect of the gas bubble on smoothong retinal folds and
flattening fish mouth tears is only required for a short period. Air is preferable in situations
in which the volume of gas is adequate to tamponade the break.
Perfluoropropane—C3F8 used in rhegmatogenous retinal detachment with severe PVR
and severe diabetic retinopathy.
Silicone oil - - use in patients who need ti travel by plane soon after surgery;
When vitreoretinal traction has not been relived or when it will recur;
Severe cases of retinal detachment;
Viral retinitis;
Severe trauma.
Problems with silicon oil :
Second surgical procedure- about 3 or 6 months after the initial surgery;
May stimulate a peri-silicone proliferation of scar tissue.
Single-operation success is in 78 %;
With one or more operation-in 89 % .
24. 1. failure to re-attach the retina:
Delayed fluid resorption- due to open retinal breaks ,abnormal RPE with a coexisting
choroiditis;
Failure due to retinal breaks– the original breaks were not sufficiently sealed,breaks that
were missed during the original surgery,new breaks;
Hemorrhage– resulting in PVR.vitrectomy is indicated if the hemorrhage does not clear
spontaneously or if re-detachment develops;
Ishemia-cerclage is typically contraindicated in patientsw with sickle cell disease and
should be used with caution in diabetic patients;
2. late re-detachment:
PVR – usually presents 6-12 weeks after initial repair;
Functional (visual) failures- epiretinal membrane ( macular pucker ).