We thank Dr. Palte for his interest in our work and pertinent comments.1The references he cites are accurate. Concerning the relatively poor reproducibility of peribulbar anesthesia efficacy, our sentence should have been better formulated, such as: “Depending on the surgeon's request for akinesia, an additional injection may be required in 0% to as high as 50% of cases.” That might help to understand why we cited only the highest rate available in the literature.2We agree that the reblock rate of peribulbar anesthesia may vary dramatically depending on block quality but also on surgeon requests and the actual procedure.
The surgical procedure variability (i.e. , phakoemulsification; manual extracapsular cataract extraction, which is still in use in many developing countries; or posterior segment surgery) may explain the surgeon's request for a more or less efficacious block. Surgeon skill/experience is also a parameter to take into account. Indeed, for phakoemulsification performed by a skillful surgeon in selected patients, topical anesthesia alone (no akinesia), or even no anesthesia at all may be enough.3
A second parameter of variability is the numerous variants of peribulbar techniques (including number of injections, site of needle introduction, volume injected, and local anesthetic choice and adjuvants), which renders comparisons difficult.
Moreover, the reblock rate depends on the evaluation of block quality, which frequently is assessed via completely subjective methods, such as “deemed by the surgeon” with no other objective measurement. Therefore, reblock rate probably is not the best way to objectively assess block quality and compare various technique evaluations in the literature.
To conclude, based on clinical and anatomic studies, we are convinced that sub-Tenon blocks produce a more consistent (reproducible) anesthesia than do peribulbar injections. This probably is due to anatomic reasons explained in our previous articles.4–7From an anatomic point of view, the difference between both technique groups can be better understood by using an analogy with perimedullary blocks: peribulbar injection can be assimilated to epidural injection, whereas sub-Tenon block corresponds to spinal injection.
This reply is dedicated to Emmanuel Nouvellon, M.D., M.Sc., who passed away just after the publication of the cited review.
*Groupe Hospitalier Universitaire Caremeau, Nimes, France. email@example.com