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Correspondence  |   September 2015
Benefits of Adding Sciatic Nerve Block to Femoral Nerve Block for Total Knee Arthroplasty
Author Affiliations & Notes
  • Rita B. Merman, M.D.
    University of Pittsburgh Medical Center, Presbyterian-Shadyside Hospital, Pittsburgh, Pennsylvania. mermanrb@upmc.edu
  • (Accepted for publication March 5, 2015.)
    (Accepted for publication March 5, 2015.)×
Article Information
Correspondence
Correspondence   |   September 2015
Benefits of Adding Sciatic Nerve Block to Femoral Nerve Block for Total Knee Arthroplasty
Anesthesiology 9 2015, Vol.123, 722-723. doi:10.1097/ALN.0000000000000770
Anesthesiology 9 2015, Vol.123, 722-723. doi:10.1097/ALN.0000000000000770
To the Editor:
Recently, Abdallah et al.1  reported the results of a double-blind, placebo-controlled, randomized trial that demonstrated the additional analgesic benefit of adding to a continuous femoral block, either a proximal (infragluteal) or a distal (popliteal) sciatic nerve block. There are a number of points in this article, which I would like to discuss. Contrary to the authors’ claim, this is not the first article to demonstrate that sciatic block makes an important contribution to continuous femoral block for analgesia after total knee arthroplasty (TKA). For example, they cite the study by Ben-David et al.2  who showed this quite convincingly more than 10 yr ago. In that study, the authors found that approximately 80% of patients, similar to the finding of Abdallah et al., have significant pain without the addition of a sciatic block. The following year, Pham Dang et al.3  conducted a randomized trial to confirm the finding of Ben-David et al. This recent article corroborates those decade old findings. Second, the failure of single-shot blocks to provide adequate duration of analgesia after TKA has been demonstrated previously.4 
Furthermore, other important issues warrant consideration. First, a preoperative single-shot sciatic block precludes distinguishing a postoperative foot drop as being due to the surgery (thus requiring action to be taken) as opposed to the block. For this reason, we recommend placing the continuous sciatic catheter with only saline and infusing local anesthetic only once intact sciatic function is demonstrated postoperatively. Second, a popliteal approach to sciatic block for TKA surgery is problematic, because it leaves any sciatic nerve injury because of the block indistinguishable from nerve injury because of the tourniquet and difficult to distinguish from nerve injury because of the surgery—with obvious medicolegal implications. A more proximal block of the sciatic nerve, such as with a gluteal approach, allows greater discrimination between a sciatic nerve injury because of the block as opposed to the tourniquet or the surgery.
Competing Interests
The author declares no competing interests.
Rita B. Merman, M.D, University of Pittsburgh Medical Center, Presbyterian-Shadyside Hospital, Pittsburgh, Pennsylvania. mermanrb@upmc.edu
References
Abdallah, FW, Chan, VW, Gandhi, R, Koshkin, A, Abbas, S, Brull, R The analgesic effects of proximal, distal, or no sciatic nerve block on posterior knee pain after total knee arthroplasty: A double-blind placebo-controlled randomized trial.. Anesthesiology. (2014). 121 1302–10 [Article] [PubMed]
Ben-David, B, Schmalenberger, K, Chelly, JE Analgesia after total knee arthroplasty: Is continuous sciatic blockade needed in addition to continuous femoral blockade?. Anesth Analg. (2004). 98 747–9 [Article] [PubMed]
Pham Dang, C, Gautheron, E, Guilley, J, Fernandez, M, Waast, D, Volteau, C, Nguyen, JM, Pinaud, M The value of adding sciatic block to continuous femoral block for analgesia after total knee replacement.. Reg Anesth Pain Med. (2005). 30 128–33 [Article] [PubMed]
Cappelleri, G, Ghisi, D, Fanelli, A, Albertin, A, Somalvico, F, Aldegheri, G Does continuous sciatic nerve block improve postoperative analgesia and early rehabilitation after total knee arthroplasty? A prospective, randomized, double-blinded study.. Reg Anesth Pain Med. (2011). 36 489–92 [Article] [PubMed]