To the Editor:—
I was happy to see the well-illustrated technique of ophthalmic anesthesia described by Ripart et al. 1I also like the concept of using akinesia as an endpoint because it is easy to define and independent of the skills of the surgeon. Working with surgeons with surgical times ranging from 5 (clear cornea technique) to 100 min, I find that the faster surgeons do well with a patchy block.
I question the use of the word “efficient” in describing the medial canthus injection technique. Although their medial canthus technique is superior to their peribulbar technique, it is not superior to the peribulbar technique used by others. 2,3Some of the discrepancy may be in the definition of a successful block because it is possible to have akinesia but not analgesia.
For the past 10 yr, we have used the following technique for more than 30,000 patients. Ten milliliters of a mixture containing half 0.75% bupivacaine and 4% lidocaine with 25 IU hyaluronidase is injected with a 16-mm, 25-gauge needle through the lid as deep as possible into the peribulbar space, half inferior lateral and half medial superior. There have been no perforations and approximately 15 cases of bradycardia, easily treated, 25–45 min after block, which may represent central effects. We have seen several cases of postoperative ptosis of the upper lid, which resolved within 1 month, without treatment. There were no other complications.
For another study, we prospectively evaluated akinesia 10 min after block, as previously described, for cataract surgery on 458 patients without glaucoma and achieved 94% akinesia. Akinesia was not graded. Any motion was considered lack of akinesia.
I suspect that the higher success rate is caused by the injection of more drug and volume. Using 2% lidocaine rather than 4% or giving only the inferior injection reduced the rate of akinesia. Based on personal communications with other ophthalmic anesthetists, I believe that my results are typical and that a 39% failure rate for the peribulbar technique is atypical. A technique necessitating that almost 40% of the patients be reblocked would be of limited use clinically. Although a meta-analysis has not been performed, from these communications, I would expect a peribulbar perforation rate of less than 1:20,000. More cases will be necessary to show that the medial canthus technique described also has a low perforation rate.