I thank Dr. Ben-David for his interest in our recently published paper on the risks associated with high injection pressure during lumbar plexus blockade.1
Here is my brief reply:
1. Dr. Hadzic is a shareholder at Macosta-Medical USA (Houston, TX); none of the remaining authors have financial interest in the device used in the study. In hindsight, although we simply studied the effect of injection pressures on epidural spread during lumbar plexus block rather than the actual devices or means of monitoring, this probably would have been best disclosed a priori.
2. It would be logical to assume that a small volume of injectate is unlikely to lead to epidural/contralateral spread of the local anesthetic, regardless of the injection pressure. Our findings, however, specifically indicate that high injection pressure during a standard single-shot technique of lumbar plexus block using 35 ml carries a significant risk of this complication. Administration of local anesthetic through a small-gauge indwelling catheter may involve an entirely different process and/or injection pressure considerations. This was not the subject of our study, and I do not have data to comment on this objectively.
3. I appreciate Dr. Ben-David’s description of an alternative technique consisting of paravertebral L1 to L2 low-volume injections for postoperative analgesia after hip arthroscopy.2
In our study, a lumbar plexus block was used as anesthesia for knee surgery, rather than for postoperative analgesia as in Dr. Ben-David’s publication.1,2
Equating anesthesia with analgesia remains a common source of discussion bias when discussing regional techniques; techniques used for analgesia are not universally interchangeable with techniques used for anesthesia. Finally, an anecdotal publication of two successful patient management scenarios using a new technique does not support claims of greater safety, efficacy, and ease-of-use advantages.2
Jeff Gadsden, M.D., F.R.C.P.C., F.A.N.Z.C.A.
St. Luke’s-Roosevelt Hospital Center, Columbia University College of Physicians and Surgeons, New York, New York. email@example.com
1. Gadsden JC, Lindenmuth DM, Hadzic A, Xu D, Somasundarum L, Flisinski KA: Lumbar plexus block using high-pressure injection leads to contralateral and epidural spread. Anesthesiology 2008; 109:683–8
2. Lee EM, Murphy KP, Ben-David B: Postoperative analgesia for hip arthroscopy: Combined L1 and L2 paravertebral blocks. J Clin Anesth 2008; 20:462–5
© 2009 American Society of Anesthesiologists, Inc.