|Year : 1961 | Volume
| Issue : 2 | Page : 20-24
Observations on Tamese's operation
BT Maskati, DG Mody
Department of Ophthalmology, K. E. M. Hospital, Bombay, India
|Date of Web Publication||31-Mar-2008|
B T Maskati
Department of Ophthalmology, K. E. M. Hospital, Bombay
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Maskati B T, Mody D G. Observations on Tamese's operation. Indian J Ophthalmol 1961;9:20-4
General improvement in surgical procedures and technique and the advent of antibiotics and corticosteroids largely reduced the many causes of partial to total annihilation of vision, but the vast debilitating group of degenerative conditions which from adolescence until death slowly but surely increase with wear and tear of life, have still remained factors for eventual blindness.
The understanding of these degenerative conditions is yet beyond us, as they are biologically determined and are part of genetic constitution.
Vasodilators, sympathectomy and other procedures either temporarily arrested the process or lead to mild transitory improvement, but ultimately the process of destruction continued to its tragic end.
Tamese's operation which aims at improving the choroidal circulation has certainly given a ray of hope to these seemingly hopeless cases; and this new idea has given an impetus to think and work on this particular aspect.
| Anatomical Basis|| |
The choroid consists mainly of blood vessels. The vessels are primarily nutritive; it nourishes the outer parts of the retina. The layer of rods and cones and the outer nuclear layer are avascular and nourished by the choriocapillaries which exist in fact for this purpose. The outer molecular layer also for the most part avascular is fed partly from the choroidal and partly from the retinal vessels, The rest of the layers of retina get their blood supply from arteria centralis retinae. The double vascular supply of the retina is very important when considering the lesions of the choroid and retina.
At macula the pigment layer and chorio-capillaries are thicker. The increased choroidal blood supply is necessary as the macula has no retinal blood vessels, this is necessary so that light can travel without hindrance to the receptive elements.
From these anatomical facts of vascular supply it is clear that in chronic central choroidoretinal lesions, either degenerative or post-inflammatory where scarring, pigment disturbances etc., have taken place as a result of sclerosis of choroidal vessels, improvement in circulation in that part by neovascularisation may help revive the perceptive elements to some extent and thus improve vision.
1. Primary pigmentory degenerations.
Though we do not know the cause, it is true that pigmentary degenerations do occur as a consequence of choroidal sclerosis, whether primary or secondary.
2. Primary choroidal sclerosis,
3. Sclerosis of choroidal vessels is observed in all conceivable forms of chorio-retinitis;
4. Senile macular degeneration;
5. Albuminuric retinitis;
6. Myopic degenerations;
7. Disciform degenerations of macula and other allied central lesions.
Operative Technique : [Figure - 1],[Figure - 2],[Figure - 3],[Figure - 4].
A retraction stitch is taken at 3 O'clock position at the limbus and eyeball retracted medially. About 8 mm., from limbus a conjunctival incision is taken, concentric with the lumbus and Tenon's capsule is cut exposing the external rectus muscle which is neatly separated. Two muscle stitches are taken at its insertion and is cut at the insertion and retracted laterally. A second retraction stitch is taken through the sclera at the ext. rectus insertion, this gives a little more working space at the posterior part of the eye-ball. Now the inferior oblique muscle is held in tentomy hook and dissected clean on its lateral aspect. A thin strip about 1.5 mm, in breadth and about 12-15 mm. in length is separated from its posterior edge and cut from its insertion. A 6-zero double-armed catgut stitch is taken through the cut end of the strip, and is left there. Now 2 mm. on outer side and above the insertion of the inferior oblique muscle a horizontal incision of about 3 mm. length is made in sclera and a sub-scleral pocket prepared of about 3 to 5 mm. in length by passing a thin iris repositor. Both the needles of the double-armed suture holding the muscle strip are passed underneath the prepared pocket and brought out and tied on the scleral surfac4 above the prepared pocket. This way the muscle strip snugly fits inside the pocket above the choroid. This manouver is easier in a myopic eye as the eye-ball is bigger.
The external rectus is sutured back in situ and Tenon's capsule and conjunctiva apposed. Pads are given to both eyes, first dressing is done on the third clay and then daily. Patient is discharged after 8 days. The most likely and feared complication during operation is puncture of choroid either during preparation of pocket or while passing the stitch. If it does happen it is not necessary to use the diathermy as it will produce more scarring, but complete the operation as usual.
| Case Reports|| |
[Table - 1] and [Figure - 1],[Figure - 2],[Figure - 3],[Figure - 4].
In all 21 eyes have been operated in 13 patients.
Fifteen eyes showed definite improvement.
Six eyes showed no improvement.
Out of 13 cases, 10 cases are of primary pigmentary degeneration, with macular affections.
Two cases of chorioretinitis.
One case of Disciform degeneration of macula.
| Discussion|| |
We know that the formation of new vessels in the retina is not uncommon, occurring in most inflammatory conditions and also where circulation has been impaired or obstructed. The process however is a purposeful one and represents an attempt to supply a system of collaterals which can take over the supply of an area, the nourishment of which has been impaired by vascular disease. This operation tries to achieve just the same thing in choroid. The muscle tissue in the suprachoroidal space acting as a foreign clement excites an irritative tissue response which ultimately leads to new vessel formation thus increasing the blood supply locally.
Is it only the new vessel formation, or the constant pull on choroid by the inferior oblique slip thereby probably augmenting the blood flow, that improves the circulation? These surmises can only be answered by some experimental study in lower animals which we shave already planned to carry out shortly in our department.
As we said before this operation has changed our mode of thinking and so it would not be very premature to mention here two suggestions which seem practicable to our mind.
(1) Why not utilise a small strip from each of the four recti muscles and place them in the sub-scleral pocket in four quadrants of the eye at the equator just as we place the strip from inf. oblique near the macula. This will improve the choroidal circulation on a wider area and improve the field of vision.
(2) Most of us have tried placenta grafting in subconjunctival pocket in these cases with very poor results. Now instead of the muscle strip if we can place a very thin slice of dried placenta in the subscleral pockets at macula and equatorial zone would it work? This method will have twofold advantages. Firstly it will excite the same irritative tissue response acting as a foreign substance. Secondly by liberating a biogenic stimulant which will come in direct contact and in greater concentration with the degenerated or the dying tissue, the end result might be more favourable.
Our initial experience of this operation raises hope that even if one does not succeed in improving the vision forthwith, its deterioration may be arrested and thus at least postpone sine die the tragic end.
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7]
[Table - 1]