Year : 1979 | Volume
: 27 | Issue : 4 | Page : 79--81
Release of subretinal fluid in retinal detachment surgery
SJ Shah, SS Badrinath
Vijaya Hospital, Vadapalani, 1, Arcot Road, Madras, India
S S Badrinath
Vijaya Hospital, Vadapalani, 1, Arcot Road, Madras
|How to cite this article:|
Shah S J, Badrinath S S. Release of subretinal fluid in retinal detachment surgery.Indian J Ophthalmol 1979;27:79-81
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Shah S J, Badrinath S S. Release of subretinal fluid in retinal detachment surgery. Indian J Ophthalmol [serial online] 1979 [cited 2020 Sep 23 ];27:79-81
Available from: http://www.ijo.in/text.asp?1979/27/4/79/32582
Release of subretinal fluid is an important and crucial step in the surgery for the detachment of retina. The evacuation of the subretinal fluid allows the approximation of the detached retina to the choroid, which has been treated either with diathermy or cryo therapy to result in a chorioretinal scar. The scleral indentation or the buckling with the solid silicone implants can be produced without undue elevation of intraocular pressure only if sufficient subretinal fluid has been drained. However, the release of subretinal fluid is one step which is fraught with complications.
Chignell had complications directly related to the release of subretinal fluid in 30% of his cases. Hitchings et al' had higher incidence of intraocular infection in cases which had undergone release of subretinal fluid.
Materials and Methods
The records of 555 patients operated for rhegmatogenous retinal detachment between 1970 and 1977 at the Vijaya Hospital and Voluntary Health Services were analysed. Most patients were subjected to scleral buckling procedure using solid silicone tires implant and encircling band. Diathermy in 336 and cyro therapy in 197 eyes were used to produce the adhesive choroiditis. The fluid was drained in 506 cases and not drained in 49 cases.
The surgical procedure: Release of subretinal fluid is generally performed through a single perforation, suitably placed, posterior to the undermined area itself or in the bed of the buckle. The perforation must be in a location where subretinal fluid is abundant and away from the vortex veins and the long ciliary arteries. The prefferred locations are: around the horizontal meridian and near 12 h. or 6 h. meridional scratch incision is made in the sclera, and its edges are caused to gape by applying surface diathermy on them. A suture is placed on the lips of the incision. A small knuckle of choroid is then exposed by further deepening the scleral incision, and it is treated with light surface diathermy in order to close choroidal vessels. Then the area is transilluminated as described above to ensure that no patent choroidal vessels remain. The choroidal knuckle is perforated with a fine diathermy needle and the subretinal fluid is allowed to escape. The suture over the perforation is temporarily tied, the mattress sutures over the silicone implant are pulled up, and any slack in the circling band is eliminated by pulling on the ends of the band. Then the fundus is carefully scrutinized with the ophthalmoscope, if subretinal fluid is still present in the area of the perforation, it is released. If a large pocket of fluid is present elsewhere and none is visible in the area of the perforation, a second perforation was done in order to empty the pocket of fluid. When all the subretinal fluid has escaped, the suture placed over the perforation is tied permanently. It is important not to pull the mattress sutures too tightly.
Observations and comments
1. Major and minor complications [Table 1] occurred in 31% of the 506 eyes operated wherein the subretinal fluid was drained. The incidence was only 4 0,/ o in 49 eyes wherein the fluid was not drained.
2. The incidence of complications between the diathermy and cryo therapy groups were similar (P=0.25) [Table 2].
3. The location of drainage site close to or away from the retinal break did not make a significant difference in the incidence of complication (P=0.10) [Table 3] A. Similarly the drainage in the bed or outside the bed did not have any significance (P=0.25) [Table 3] B Drainage was attempted in almost all meridians though more often closer to horizontal meridian. 75% of drainage for subretinal fluid was done in the 8° -10° and 2° -4° clock horizontal meridians. 74% of complications occurred in the above mentioned horizontal meridians. Drainage in 166 eyes in the upper half clock meridians resulted in 19% incidence in complications. Drainage in 253 eyes in the lower half clock meridians resulted in 24% incidence of complications. However, there is no statistically significant difference in the incidence of complication in the upper half clock meridians compared to the lower half clock meridians (P=0.10).
4. The aphakic patients were more vulnerable to complications during the release of subretinal fluid. There was no significant higher incidence of complications in myopes.
5. When perforation was done, the complications occurred in 22% of 419 eyes. The incidence increased with increasing number of attempts at drainage of subretinal fluid reaching 90% in cases with more than 4 perforations, most of them were major complications.
6. The retina was successfully reattached in 81% of the 515 eyes operated. Inspite of the development of drainage site complications seen in 156 cases the retina was successfully reattached in 124 cases, (79%). The vision improved in 105 (68%), maintained in 5 (3%) and deteriorated in 46 (29) eyes. The failure to reattach retina occurred in 24.5% of the cases in which drainage site complications occurred compared to 18.5% in the uncomplicated cases.
If buckle is placed properly even in cases where subretinal fluid is present at the conclusion of surgery, it tends to get absorbed and results in higher success rate of anatomical reattachment. Whereas, even if the fluid is drained till dry if the surgical procedure is faulty, it doess lead to failure of surgery.
In this series out of 116 failures the formation of a new retinal break was responsible for failure in 20 cases. The perforation site complication was directly responsible for failure in 9 cases (1.6%). Precaution to be observed in the release of subretinal fluid:
1. Drainage should be done where the subretinal fluid is maximal and abundant in quantity to be confirmed by ophthalmoscopy.
2. It should be done away from the long posterior ciliary arteries and vortex ampullae.
3. The drainage site must be prepared very cautiously using transillumination and choroidal diathermy.
4. Examine carefully on the operating table and rule out rapidly shifting nature of subretinal fluid.
5. Perform the drainage in the most dependent part. If necessary, turn the head to either one of the sides to make the drainage site more dependent than the rest of the areas.
6. Avoid drainage very far anteriorly.
7. Use sharp electrode for puncturing the choroid. Blunt electrodes would just push the choroid inwards without puncturing it.
8. If the eye is too soft, there is difficulty in draining the subretinal fluid. In such situations pull up one or two mattress sutures holding the implant to raise the intraocular pressure.
On the other hand, too high an intraocular pressure would result in sudden gush of subretinal fluid and incarceration of retina and must be avoided.
9. If the drainage stops, do not continue to squeeze the eye hard trying to get more subretinal fluid. That will only lead to incarceration of retina and even loss of vitreous.
Once the drainage stops, it is imperative to close the drainage site first before the scleral mattress sutures are pulled up and tightened.
|1||Chignell, A.H., 1972, Amer. J. Ophthal., 73, 860.|
|2||Hitchings, R.A., Levy, I.S. and Chignell, A.H., 1974, Brit. J. Ophthal., 58, 588.|