I read the article by Azad et al on “Modified needle drainage. A safe and efficient technique of subretinal fluid drainage in scleral buckling procedure” with interest. I would like to make a few comments, observations and suggestions. In the article they have compared drainage of subretinal fluid by two different techniques: 1) MND - modified needle technique of theirs and 2) CD - conventional technique as described by Schepens.
In the MND technique [Figure - 1] the authors use a straight 26 no. disposable needle on a syringe without the plunger and puncture the sclera perpendicularly while draining the subretinal fluid. Since they enter perpendicularly with a very sharp 26 no. needle there is no control over the force and the depth of puncture, leading to an increased risk of complications. They also attach a syringe (though without the plunger) thereby increasing the overall weight; the fine control is reduced as more force is now needed to overcome the weight of the syringe.
During my vitreous-retina fellowship (under Dr. P N Nagpal), we performed subretinal fluid drainage by a technique much better than the MND technique the authors describe, with few differences. Our technique [Figure - 2] consisted of using the same 26 no disposable needle but we would bend only the tip by 2 mm like in anterior capsulotomy and not bend the shaft. We would also not attach any syringe to it. We would then puncture the sclera such that the tip would be perpendicular to the sclera but the shaft would be tangential to the sclera and act like a guard to prevent entry beyond 2 mm. Since no syringe is attached the weight is reduced to ensure fine control. Following the puncture, we will immediately withdraw the needle and apply pressure over the globe. The bent tip length could be reduced in case of shallow detachments.
I have used this technique in several cases and I am sure there are many vitreous-retina surgeons who have also done so, with success. This technique is safer and quicker. Some of the cases of multiple punctures or complication the authors mention could be because of the perpendicular needle with syringe and lack of control over the depth of puncture.
I wish to thank the authors for bringing such a technique into consideration of the fraternity.
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1. Azad RV, Kumar A, Sharma YR, Rapal. Modified needle Drainage. |jA safe and efficient technique of subretinal fluid drainage in scleral buckling procedure Indian J Ophthalmol. 2004;52:211–14