MT1 Flashcards
where are most retinal holes? what type are they most commonly?
- atrophic
- in the periphery
where are flap tears
at the equator
what type of holes have a less chance to cause an RD
free operculated holes
most breaks are in what quadrant of the retina
superior temporal
prevalence of RDs over lifetime
0.7%
incidence of retinal breaks in the population
5-7%
what % of holes are associated w/lattice?
80%
what are 3 goals of RD surgery
- put retina break back in apposition to the RPE/choroid in region of the breaks
- create chorioretinal adhesion around the breaks
- offset all vitreoretinal traction
in uncomplicated RD in the presence of a flap tear, what procedure had the lowest failure rate?
scleral buckle
what is the failure of vitrectomy vs. victrectomy +buckle in complicated RD
vitrectomy had lower failure than vit+buckle
definition of cryotherapy in RD
transconjunctival application of a freezing probe to form a chorioretinal adhesion
how does cyrotherapy work (molecular level)
expansion of high pressure nitrous oxide into end of a probe which generates temperatures of -89 degrees Celcius
when do you use cyrotherapy?
- retinal breaks
- can be used in conjunction with scleral buckling and pneumatic retinoplexy
advantages of cyrotherapy over laser photocoagulation
- treatment of anterior lesions
- treatment through media opacities, vitreous heme
- delivered upon lesions requiring scleral depression
post-procedure on cyrotherapy includes:
- patch eye for 4 hours
- chemosis is common
- refrain from strenuous physical activity for 1 week
complications of cyrotherapy
- inadvertent tissue freezing (ex: muscles causing transient diplopia, and adjacent tissue)
- dispersion of RPE cells
goals of scleral buckling therapy
- close retinal breaks by placing the sensory retina next to the RPE
- reduce the dynamic vitreo-retinal traction at sites of adhesion
indication for scleral buckling surgery
-routine rhegmatogenous retinal detachments
what are contraindications for scleral buckling surgery
- posterior retinal breaks
- proliferative vitreoretinopathy
what are the 3 types of explants for scleral buckling
- radial
- segmental circumferential
- encircling
radial explants for scleral buckling are for:
- breaks that extend more posterior
- large U-shaped tears
segmental circumferential explants for buckling are for:
- multiple breaks in more than one or two quadrants
- anterior breaks or wide breaks (dialysis)
encircling explants for buckling are for:
- breaks involving 3 or more quadrants
- extensive RD without detectable breaks
- moderate proliferative vitreoretinopathy
- lattice degeneration involving 3 or more quadrants
4 factors that affect buckle height
- diameter of explant
- separation of sutures
- tautness of sutures
- intraocular pressure
what causes increase buckle height?
- greater the explant diameter
- greater the separation of sutures
- tighter the sutures
- lower the IOP
steps of scleral buckling
- prep (dilation, sterilization, anesthesia)
- peritomy: resection of conjunctiva and Tenon’s capsule
- bridle sutures around EOMs
- localization of breaks
- cyrotherapy around retinal break
- application of scleral explant
- suture conjunctiva and Tenon’s
post-op management medications for scleral buckling
cycloplegic, antibiotic-steroid drops, pain meds
what are some surgical complications from scleral buckling
- buckle may be inadequate size, position, and indentation
- missed breaks
- fishmouthing
what will happen if buckle is too tight?
- radial retinal folds
- anterior segment ischemia
what are some causes of late failure of buckling
- proliferative vitreoretinopathy
- migration or extrusion of explant
- extraocular muscle imbalance
describe pneumatic retinopexy
-flotation force and surface tension of an intraocular gas bubble utilized in reattachment and closure of retinal breaks against the eye wall
indications for pneumatic retinopexy
- RD with posterior breaks
- RD w/ 1 or more breaks no larger than 1 clock hour
- breaks in superior retina (upper 8 clock hours)
contraindications of pneumatic retinpexy
- breaks larger than 1 clock hr or multiple breaks extending over 1 clock hour
- breaks in the inferior retina
- presence of proliferative vitreoretinopathy
- cloudy media which disallows full assessment of the retina
- severe or uncontrolled glaucoma
- physical limitations which limit ability to maintain post-op positioning
advantages of pneumatic retinopexy over scleral buckling
- outpatient setting
- no incisions required
- visual results are better
- lower incidence of cataracts (1/4th)
- morbidity of the eye is lower (pain, diplopia, nausea, psuedoptosis)
types of gas in pneumatic retinopexy
- air
- sulfur hexafluroride (SF6)
- perfluoroethane (C2F6)
- perfluoropropane (C3F8)
you want an intraocular bubble the size of ____ for pneumatic retinopexy
-1-1.5
laser photocoagulation or cyrotherapy?
-performed prior to gas injection
cyrotherapy
laser photocoagulation or cyrotherapy?
-better for posterior breaks and vitreous traction
-laser photocoagulation
laser photocoagulation or cyrotherapy?
-adhesion is much quizker and more form
laser photocoag.
how long does resorption of subretinal fluid take with the bubble in place against the break
24-48 hours
complications of pneumatic retinopexy
- fluid is not reabsorbing
- fish eggs
- trapped bubble
- subretinal gas
- increased IOP
- cataract formation
- new retinal breaks (7-23%)
treatment success w/initial pneumatic retinopexy treatment
63-84% success
advantages of vitrectomy
- direct relief of vitreous traction
- proliferative ret. can be removed w/membrane peeling
- combine w/scleral buckling
- complete reattachment at the time of surgery
- success rate 85-90%
contraindications for vitrectomy
-active neo of the iris (prognosis for the eye is poor)
vitrectomy studies in type I diabetics showed
non-clearing vit. heme should be operated on within 6 months
vitrectomy studies in type II diabetics showed
no difference in surgeries performed at 6 months or 1 year
