|Year : 1982 | Volume
| Issue : 6 | Page : 579-581
Innovations of drainage of subretinal fluid
Manju Kulkarni, SS Badrinath
Sankara Nethralaya, 18, college road, Madras-6
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Kulkarni M, Badrinath S S. Innovations of drainage of subretinal fluid. Indian J Ophthalmol 1982;30:579-81
Drainage of subretinal fluid is the most crucial step in the Retinal Detachment Surgery. A previous study reportcd incidence of minor and major complications resulting from the release of subretinal fluid of 31% in 555 eyes operated for detachment of retina. We decided to use the operating microscope in the preparation of subretinal fluid drainage site and study its utility in prevention of complications.
| Materials and methods|| |
Fifty consecutive surgeries for detachment of retina wherein the subretinal fluid was evacuated forms the basis of the study. Both implant and explant buckling procedures were adopted. A careful indirect ophthalmoscopic inspection of the fundus was carried out to select drainage site. The blunt localising electrode of MIRA was used to depress the selected drainage site to eraluate the amount of fluid in the subretinal space. A site where it was maximal was chosen. Mostly it was on either side of horizontal recti far away from the vortex ampoulle and the long posterior ciliary artery and nerves. In some cases, it was in the bed of the buckle and in others it was outside.
The magnification and the illumination obtained with the operating microscope, were utilised in preparing and performing the release of subretinal fluid at the selected drainage site. The coaxial illumination offers shadow free operative site. 6X magnification was optimal, The arm extending from the floor stand from which the microscope is suspended was positioned at right angles to the drainage site.
Inspection of superficial layers and diathermisation of scleral vessels are carried out, Desmarre's scarifier is used to produce the radial cut in the sclera. 3/4 mm long sclerotomy is slowly and carefully made. The incision is always perpendicular to scleral surface. If sclera is too thick diathermy point is applied to edges of sclerotomy opening to make it gape. Thus the deep layers of sclera come into view and the gentle perpendicular incision is extended further deeper. Bleeding from any of the scleral vessels is stopped by diathermisation. As the deeper layers are incised a knuckle of choroid approximately 2 mm long is exposed bulging outwards from the depths of the wound Inspection of the kunckle of choroid for the presence of blood vessels and cauterisation of the same are carried out under the microscope. The herniating uveal tissue is pierced obliquely by the penetrating electrode without current. A small hole in the black choroidal tissue is visible through which the subretinal fluid drains slowly and continuously. Till the subretinal space has been emptied. Delibrate steps to keep the intracular pressure low, such as partial release of traction sutures, the retractor and loosening of mattress sutures holding the implant are undertaken to avoid precipitous release of subretinal fluid and consequent retinal incarceration. As more and more fluid is being drained, gentle pressure with cotton applicators sticks aids in making up the lost volume and bringing the ocular pressure to normal level. Excessive pressure and squeezing of the eye ball are avoided. When the drainage is complete the perforation site is closed. If it is located under the implant or explant. the mattress suture underlying it is first pushed up and tightened and if it is outside a 4/0 suture through lips of the sclerotomy applied prior to piercing of the choroid is tied before adjusting any other suture over the buckle. The operating microscope is used again at the procedure. After adjusting other mattress sutures, indirect ophthalmoscopic examination is carried out to study the fundus with particular reference to complications at the perforation site such as choroidal haemorrhage, retinal hole formation, incarceration, vitreous haemorrhage etc.
| Observations discussion|| |
I. The incidence of bleeding from the superficial scleral vessels and choroidal vessels while preparing the sclerotomy site and perforation of choroid has been reduced. [Table - 2]
2. The incidence of major complications such as retinal and vitreous haemorrhage have also been reduced. [Table - 1]
3. Multiple punctures, either at the same site or at different sites are known to produce more complications, particularly iatrogenic rectinal holes. The use of microscope improved the surgical efficiency and in F0% of the cases the puncture was successful at the first attempt. The greater magnification, improved illumination permitted accurate piercing of the choroid obliquely for a short distance.
4. The collagen fibres of sclera, arranged in 3 layers run in different directions in each layer, We observed that obliquely placed innermost layers needed a very sharp knife to be incised. The presence of even a thin layer of sclera or a few fibres of scleral tissue prevents escape of subretinal fluid though perforating electrode may have pierced all the layers incl . uding the choroid; such a thin layer of tissue also has a valve like effect permitting drainage of fluid at times only when the excessive pressure is applied to squeeze the eye from certain directions.
5. Flush of choroidal pigment is classically described as the end point of subretinal fluid drainage. We have observed that choroidal. pigment flow takes place throughout the subretinal fluid drainage.
6. Surprisingly in a large number of cases a small quantity of suprachoroidal fluid escapes on completion of sclerotomy incision. This seems to indicate that in majority of cases of detachment of retina, gross choroidal detachment tends to occur.
7. The use of microscope during this step of the operative procedure was found to be a time consuming, cumbersome and occassionally resulted in contamination due to inadvertant touching of the unsterile microscope parts.
8. It was difficult to obtain satisfactory view of the drinage site through the microscope if it was located far behind the equator since observation system of the microscope is vertically oriented.
[Table - 1], [Table - 2]