Free
Correspondence  |   July 2011
Seeing Eye to Eye on Ophthalmic Regional Anesthesia
Author Affiliations & Notes
  • Philippe Cuvillon, M.D., Ph.D.
    *
  • *Groupe Hospitalier Universitaire Caremeau, Nimes, France.
Article Information
Correspondence
Correspondence   |   July 2011
Seeing Eye to Eye on Ophthalmic Regional Anesthesia
Anesthesiology 7 2011, Vol.115, 209-210. doi:10.1097/ALN.0b013e31821d12aa
Anesthesiology 7 2011, Vol.115, 209-210. doi:10.1097/ALN.0b013e31821d12aa
In Reply:
We thank Dr. Palte for his interest in our work and pertinent comments.1 The 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.2 We 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.4–7 From 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.
References
Nouvellon E, Cuvillon P, Ripart J: Regional anesthesia and eye surgery. Anesthesiology 2010; 113:1236–42Nouvellon, E Cuvillon, P Ripart, J
Bloomberg LB: Administration of periocular anesthesia. J Cataract Refract Surg 1986; 12:677–9Bloomberg, LB
Pandey SK, Werner L, Apple DJ, Agarwal A, Agarwal A, Agarwal S: No-anesthesia clear corneal phacoemulsification versus  topical and topical plus intracameral anesthesia. Randomized clinical trial. J Cataract Refract Surg 2001; 27:1643–50Pandey, SK Werner, L Apple, DJ Agarwal, A Agarwal, A Agarwal, S
Ripart J, Prat-Pradal D, Vivien B, Charavel P, Eledjam JJ: Medial canthus episcleral (sub-Tenon) anesthesia imaging. Clin Anat 1998; 11:390–5Ripart, J Prat-Pradal, D Vivien, B Charavel, P Eledjam, JJ
Ripart J, Metge L, Prat-Pradal D, Lopez FM, Eledjam JJ: Medial canthus single-injection episcleral (sub-tenon anesthesia): Computed tomography imaging. Anesth Analg 1998; 87:42–5Ripart, J Metge, L Prat-Pradal, D Lopez, FM Eledjam, JJ
Ripart J, Lefrant JY, Vivien B, Charavel P, Fabbro-Peray P, Jaussaud A, Dupeyron G, Eledjam JJ: Ophthalmic regional anesthesia: Medial canthus episcleral (sub-tenon) anesthesia is more efficient than peribulbar anesthesia: A double-blind randomized study. Anesthesiology 2000; 92:1278–85Ripart, J Lefrant, JY Vivien, B Charavel, P Fabbro-Peray, P Jaussaud, A Dupeyron, G Eledjam, JJ
Ripart J, Lefrant JY, de La Coussaye JE, Prat-Pradal D, Vivien B, Eledjam JJ: Peribulbar versus  retrobulbar anesthesia for ophthalmic surgery: An anatomical comparison of extraconal and intraconal injections. Anesthesiology 2001; 94:56–62Ripart, J Lefrant, JY de La Coussaye, JE Prat-Pradal, D Vivien, B Eledjam, JJ