Anesth Analg 2004;99:954-955
© 2004 International Anesthesia Research Society
doi: 10.1213/01.ANE.0000131689.07385.34
LETTERS TO THE EDITOR
Postoperative Analgesia Following Total Knee Arthroplasty
Scott A. Lang, MD, and
M. E. Rooney, MD
Department of Anesthesia, University of Calgary, Calgary, Alberta, Canada
Department of Anesthesia, Victoria Hospital, Prince Albert, Saskatchewan, Canada
To the Editor:
Ben-David et al. (1) investigated the need for a continuous sciatic nerve block (CSI) in addition to a continuous femoral nerve block (CFI) for postoperative analgesia following total knee arthroplasty (TKA). Their experience suggests that approximately 80% of patients benefit from the addition of a CSI. Their study was motivated by concerns their surgeons had about the routine use of a CSI, namely a form of masked mischief (e.g., common peroneal nerve injury, compartment syndrome) (2). The authors responsibly remind us that there continues to be controversy regarding the need for a CSI following TKA and that, although their study and experience are suggestive of the need for a CSI (in addition to a CFI), larger randomized and blinded studies with standard postoperative rehabilitative regimens need to be done to confirm or refute their suspicions.
Our surgeons expressed similar concerns to us in the mid-1990s. We also found production pressure (3) to be a significant factor that discouraged our use of dual continuous peripheral nerve blocks. We developed a technique whereby the terminal fibers of both the sciatic and the obturator nerves can be blocked by intraoperative deposition of local anesthetic in the fat pad behind the knee (4). We called the technique the ‘transcruciate knee block." In a small group of patients we demonstrated the utility of the technique. Although the original description consists of a single injection, the technique can be modified by inserting and tunneling a catheter. The technique had two major advantages in our opinion. It helped eliminate production pressure. More importantly, it enhanced the analgesia provided by a CFI without blockade of the parent trunk of the sciatic nerve. We would predict the principle risks with the technique to be vascular injury and infection, although we feel these risks should be very low and manageable.
We did not have an opportunity to continue investigating the utility of the transcruciate knee block because of career choices and the reorganization of services within our health region. However, we would encourage further investigation of the technique if avoidance of sciatic nerve blockade is desirable and the incremental benefit of blocking the sciatic and obturator nerve contributions to the knee joint is substantial.
References
- 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.[Abstract/Free Full Text]
- Bromage PR. Masked mischief. Reg Anesth 1993; 18: 143–4.[Medline]
- The Anesthesia Patient Safety Foundation Newsletter: Production Pressure. 2001 (Spring);16(1). Available at http://www.gasnet.org/societies/apsf/loadurl/loadurl.php?www.gasnet.org/societies/apsf/newsletter/2001/spring/.
- Rooney ME, Lang SA, Klassen L. Intraoperative transcruciate injection: a new approach to postoperative analgesia following total knee arthroplasty. Techniques in Regional Anesthesia and Pain Management 1999; 3: 13–8.
Response
Bruce Ben-David, MD, and
Jacques Chelly, MD PhD
Clinical Associate Professor of Anesthesiology, University of Pittsburgh Medical Centers-Shadyside Hospital
Professor of Anesthesiology and Orthopedic Surgery, University of Pittsburgh Medical Centers, Pittsburgh, PA
In Response:
We appreciate the interest Drs. Lang and Rooney have shown in our work and their implicit endorsement of our conclusion that sciatic blockade is usually necessary after TKA to provide satisfactory conduction analgesia. It is particularly gratifying to see that the nature of discussion has shifted to a plane of how best, rather than whether, to provide continuous peripheral neural blockade for postoperative analgesia.
Certainly production pressures are a reality and, sadly, one can expect little patience for pain management practices that delay case flow. Yet it is hard to compare the situation today with that of only 10 years ago. Little dedicated equipment was then available for continuous peripheral neural blockade (CPNB) which usually required a fair amount of effort and jerry-rigging. Today multiple manufacturers market prepackaged CPNB sets, which greatly simplifies matters. Even more important than equipment advances has been the development of greater organizational sophistication. Production pressure becomes much more manageable if one is doing the blocks, as we are, in a properly equipped preoperative area, and if they are in the hands of a dedicated acute interventional pain service (AIPS). If blocks must be done by each individual anesthesiologist in the OR, then in all likelihood they will not be done at all. In our practice, the solution has been formation of a dedicated AIPS team whose sole function is to manage postoperative pain. The assigned attending will spend a week at a time on the service. His duties include both placing the blocks (single and/or continuous) and having primary responsibility for managing the patient’s pain postoperatively. Clearly, the economics and logistics of a dedicated acute pain service will vary for each institution and will require a certain amount of creative adaptation. However, over the years it has become clear to us that 1) a separate dedicated AIPS team with a consistent approach and 2) the continuity of patient care provided by at least weekly assignment of one of the team are critical elements of a successful acute pain program. A situation where each attending does or does not manage postoperative pain as time and inclination allow is a prescription for both problems and failure.
While the technique suggested by Drs. Lang and Rooney is interesting and may indeed prove useful, it raises several issues. Use of a single shot block provides time-limited relief and, in fact, will create the very situation postoperatively that we wish to avoid—the inability to distinguish nerve injury from neural blockade. Our method has evolved to the point where we now place the sciatic catheter using saline injectate only. No local anesthetic (LA) is administered via the catheter until, after surgery, the patient has demonstrated intact sciatic function and is complaining of posterior pain. As for use of a catheter passing through or in close proximity to the wound, in our experience, orthopedic surgeons are wary of placing infusion catheters in or about the wound when prosthetic implants are used. Since as many as 1% of implants may suffer from infection, then regardless of whether or not a surgical wound-sited LA catheter predisposes to infection, it will certainly predispose to medicolegal liability (as the catheter will doubtless be blamed for introducing infection). There are several companies currently marketing wound infusion catheters and pumps, and this seems to be a common theme of concern. There are, to our knowledge, no published direct comparisons of CPNB and LA wound infusions, but our impression remains consistent with that of Chelly et al. (1), who found superior analgesia from CPNB versus intraarticular LA infusion. Nevertheless, such an approach to the use of local anesthetic as part of a multimodal analgesic plan may be the most practical in many locales.
Reference
- Chelly JE, Harvey G, Duc V, et al. Ropivacaine infusions via perineural or intraarticular catheters for ambulatory postoperative pain management [abstract]. Anesthesiology 2000; 93: A875.
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