Primary Retinal Detachment

Complications of Drainage 41
encircling entailed. Drainage also shortened recovery time,
which both relieved the unease of the surgeon and shortened
hospital stays from weeks and months (Treatment of Samelsohn,
[7]).
Schepens reserved bed rest for macula-on retinal detachments.
For all other detachments, subretinal fluid was desirable, since it
made volume reduction more effective and safer: “In all other cases,
the patients are encouraged to be up and about, in order to keep
the retina detached prior to surgery, because the scleral buckling
operation, which necessarily decreases the volume of the eye, requires
the loss of ample subretinal fluid at the time of operation”
[2]. The amount of fluid to be removed from the eye was investigated
by Thompson and Michels. The volume displacement of a
2.5-mm-wide band was measured to be 0.5 ml; with explants, the
displaced volume could be close to 2 ml or up to 45% of the vitreous
cavity [24].
Complications of Drainage
Complications of drainage include hemorrhage, choroidal detachment,
retinal incarceration, iatrogenic retinal holes, and infection.
Cibis wrote about the uncertain nature of a release of subretinal
fluid:“This is perhaps the most dangerous step in any of the retinal
detachment procedures presently employed,except where Custodis’
technique is used” [25].
Intraocular bleeding (major retinal, subretinal, or vitreal) was
seen in 14.4% of drained versus 3.3% of undrained cases [26].
Choroidal detachment occurred in 8.6% of drained versus 1.6% of
undrained cases. Both bleeding and choroidal detachment reduced
the probability of reattachment and good postoperative vision
in this population-based study [26]. Choroidal edema was found
more frequently in older patients after drainage, hypotony, encircling,
larger buckles, more extensive cryopexy and more complete
vortex vein obstruction [19].