Continuous peripheral nerve blockade (CPNB) is a technique that promises much, delivers plenty, and may yet be capable of more. Attractive to patients and clinicians alike for its ability to prolong the duration of analgesia, and to allow individualized dosing to be tailored to need, the uses of CPNB extend beyond the confines of hospitals to the continuation of high-quality analgesia in the ambulatory setting. Postoperative benefits of CPNB include reduced use of opioids (and consequently reduced side effects),1–3 reduced pain on movement,1,4 and improved quality of sleep.5 Numerous other indications have been described, including the retrieval of trauma patients, and the induction of sympathectomy to improve peripheral perfusion.3 Technical advancements in equipment and nerve localization, combined with a range of local anesthetic drugs and delivery systems, provide the anesthesiologist with what may seem a dizzying array of variables in the practical application of this technique. In this issue of Anesthesia & Analgesia, Brian Ilfeld, himself a major contributor to evidence in the field of CPNB, reviews a very large and heterogeneous body of work relating to the applications of CPNB in modern anesthetic practice.3 The result is a comprehensive summary and insightful interpretation of the literature to date, as well as the exposure of many significant voids that still remain regarding the optimal use and delivery of this important treatment modality.
The postoperative aims of CPNB are intimately related to the surgical procedure concerned, whether or not a period of intense pain is expected (and for how long), and how motor blockade may impact upon the rehabilitation phase. A case in point is the use of continuous femoral nerve block (CFNB) following total knee arthroplasty (TKA), a surgical procedure often associated with severe pain, whose site is innervated by more than one major peripheral nerve, and which requires a period of intense postoperative physical therapy and rehabilitation. This is one of the most extensively researched applications of CPNB, with over 30 of the articles referred to in the accompanying review relating to CFNB in the setting of TKA.3 However, CFNB has been associated with quadriceps weakness,6,7 which may impair active participation in physical therapy, and has been implicated in falls.8 In fact, dense motor block to reduce muscle spasm was the postoperative goal for successful CFNB in one of the landmark studies designed to investigate the use of CFNB following TKA.4 This outdated paradigm included prolonged admissions in rehabilitation centers and involved passive motion rehabilitation techniques, as did another influential study of CFNB.9 In the modern-day reality of accelerated clinical pathways, the seemingly competing goals of analgesia and mobility surrounding TKA therefore merit thoughtful consideration and further evaluation. Furthermore, the ideal local anesthetic regime for CPNB must be defined by clinically meaningful outcomes for contemporary practice, especially pain and mobility during hospitalization and functional recovery in the longer term.
Delving more deeply into the objectives of CPNB therefore generates more questions. How may sensory and motor block be optimally balanced and how may this balance change at different anatomical sites? Whereas the combination of opioids and low-concentration local anesthetics in epidural infusions can produce effective analgesia with minimal motor block,10,11 there are limited data for how volume, concentration, and total mass of local anesthetic influence motor and sensory blocks in CPNB. It appears likely that the site of block may have a bearing on this, with anatomical differences in the spaces around nerves and topographical differences within the nerves themselves potentially playing a role in the relationship between concentration, volume, and clinical effects.12,13 Total drug dose appears to be the primary determinant of clinical effects in continuous lumbar plexus block,14 whereas profound sensory block appears more common in low-concentration, high-volume popliteal–sciatic block,12 and mixed results have been presented for continuous interscalene block.3 There are limited data on the optimal dose and concentration for CFNB following TKA, with most investigations focusing on the analgesic effects of changing concentration2,15 and scant evidence regarding the effects of concentration on motor block and mobility.16 Ilfeld and colleagues recently attempted to quantify the effects of a 4-day CFNB infusion, in comparison with a CFNB infusion stopped the morning after surgery, on readiness to hospital discharge following TKA, according to 3 explicit criteria relating to both mobility and analgesia.6,17 In 2 studies of near-identical methodology, but different settings (research center versus general orthopedic ward), the time to readiness to discharge in the 4-day CFNB group was significantly shorter, although the effect was less marked in the general orthopedic ward setting. Because all patients were ASA physical status II, and preoperative daily opioid use was an exclusion criterion, it is uncertain whether these results are generalizable to the wider TKA population. It is also noteworthy that although the mode of local anesthetic administration, patient-controlled bolus dosing instead of continuous rate infusion, can reduce the total consumption of local anesthetic without compromising analgesia,18–20 there is insufficient evidence to support any relative preservation of motor function.
In his review, Ilfeld addresses the evidence for alternatives to CPNB, and duly calls for further research.3 By targeting nerves more peripherally, CPNB could be used to more elegantly achieve analgesia with fewer troubling motor effects. One interesting and promising trial of continuous blockade of the obturator and saphenous nerves (adductor canal block) has reported pain scores and morphine consumption following TKA comparable to studies using femoral nerve block.21 Adductor canal block should theoretically have minimal motor effects; unfortunately, quadriceps strength was not an outcome measured in this preliminary study.
There is also a growing body of evidence around local infiltration analgesia (LIA) during and after major joint arthroplasty. The simplicity and apparent safety of this approach to analgesia, combined with an avoidance of the motor block associated with CPNB, make it particularly appealing as an alternative strategy. A recent review of the evidence on LIA for hip and knee arthroplasty commented on a number of methodological issues complicating data interpretation, but concluded that there is evidence to recommend intraoperative LIA for TKA for an initial postoperative analgesic effect of around 6 to 12 hours.22 There have been few direct comparisons of CFNB and LIA and only 1 double-blind randomized comparison of these 2 techniques.23 This study reported significantly less morphine use, and improved functional recovery at 6 weeks, in the CFNB group. In addition, there was no difference between groups in the secondary outcome of 2-minute walk tests on postoperative days 1 to 3. This is in contrast to a nonblinded comparison of CFNB with LIA, which reported lower pain scores, less morphine consumption, and a greater number of patients mobilizing more than 3 m on postoperative day 1 in the LIA group, although the CFNB local anesthetic infusion regimen was most unconventional.24 Another recent comparison of LIA and CFNB following TKA found pain scores and morphine consumption to be similar in the first 24 postoperative hours, but was not blinded, and had less robust methodology for data collection than did the study by Carli and colleagues.23,25 It is clear that high-quality double-blind trials are needed to further evaluate the roles of CFNB and LIA in the context of TKA.
Finally and importantly, with the exception of the comparison of CFNB and LIA by Carli and colleagues,23 most investigations of long-term outcomes suggest little impact of extended CPNB on measures of function in the months and years following hip or knee arthroplasty.1,4,9,26–31
Where then do catheters belong in modern practice? The potential applications are many, the variables in practice are myriad, but the aims of adequate analgesia combined with early mobilization, rapid hospital discharge, and the best possible long-term outcomes present a challenge not yet fully answered.
Name: Dorothea H. Morfey, BSc, MBBS, FRCA.
Conflict of Interest: Dr. Morfey has no conflict of interest to declare.
Name: Vincent W. S. Chan, MD, FRCPC.
Conflict of Interest: Dr. Chan receives equipment support and honoraria from Philips Medical Systems, SonoSite, and GE Medical.
Name: Richard Brull, MD, FRCPC.
Conflict of Interest: Dr. Brull has no conflict of interest to declare.
This manuscript was handled by: Spencer S. Liu, MD.
1. Salinas FV, Liu SS, Mulroy MF. The effect of single-injection femoral nerve block versus continuous femoral nerve block after total knee arthroplasty on hospital length of stay and long-term functional recovery within an established clinical pathway. Anesth Analg 2006;102:1234–9
2. Seet E, Leong WL, Yeo ASN, Fook-Chong S. Effectiveness of 3-in-1 continuous femoral block of differing concentrations compared to patient controlled intravenous morphine for post total knee arthroplasty analgesia and knee rehabilitation. Anaesth Intensive Care 2006;34:25–30
3. Ilfeld BM. Continuous peripheral nerve blocks: a review of the published evidence. Anesth Analg 2011;113:904–25
4. Capdevila X, Barthelet Y, Biboulet P, Ryckwaert Y, Rubenovitch J, d'Athis F. Effects of perioperative analgesic technique on the surgical outcome and duration of rehabilitation after major knee surgery. Anesthesiology 1999;91:8–15
5. Mariano ER, Afra R, Loland VJ, Sandhu NS, Bellars RH, Bishop ML, Cheng GS, Choy LP, Maldonado RC, Ilfeld BM. Continuous interscalene brachial plexus block via an ultrasound-guided posterior approach: a randomized, triple-masked, placebo-controlled study. Anesth Analg 2009;108:1688–94
6. Ilfeld BM, Le LT, Meyer RS, Mariano ER, Vandenborne K, Duncan PW, Sessler DI, Enneking FK, Shuster JJ, Theriaque DW, Berry LF, Spadoni EH, Gearen PF. Ambulatory continuous femoral nerve blocks decrease time to discharge readiness after tricompartment total knee arthroplasty: a randomized, triple-masked, placebo-controlled study. Anesthesiology 2008;108:703–13
7. Barrington MJ, Olive D, Low K, Scott DA, Brittain J, Choong P. Continuous femoral nerve blockade or epidural analgesia after total knee replacement: a prospective randomized controlled trial. Anesth Analg 2005;101:1824
8. Ilfeld BM, Duke KB, Donohue MC. The association between lower extremity continuous peripheral nerve blocks and patient falls after knee and hip arthroplasty. Anesth Analg 2010;111:1552–4
9. Singelyn FJ, Deyaert M, Joris D, Pendeville E, Gouverneur JM. Effects of intravenous patient-controlled analgesia with morphine, continuous epidural analgesia, and continuous three-in-one block on postoperative pain and knee rehabilitation after unilateral total knee arthroplasty. Anesth Analg 1998;87:88–92
10. Cohen SE, Yeh JY, Riley ET, Vogel TM. Walking with labor epidural analgesia: the impact of bupivacaine concentration and a lidocaine–epinephrine test dose. Anesthesiology 2000;92:387–92
11. Wilson MJA, MacArthur C, Cooper GM, Shennan A, COMET Study group UK. Ambulation in labour and delivery mode: a randomised controlled trial of high-dose vs mobile epidural analgesia. Anaesthesia 2009;64:266–72
12. Ilfeld BM, Loland VJ, Gerancher JC, Wadhwa AN, Renehan EM, Sessler DI, Shuster JJ, Theriaque DW, Maldonado RC, Mariano ER. The effects of varying local anesthetic concentration and volume on continuous popliteal sciatic nerve block: a dual-center, randomized, controlled study. Anesth Analg 2008;107:701–7
13. Le LT, Loland VJ, Mariano ER, Gerancher JC, Wadhwa AN, Renehan EM, Sessler DI, Shuster JJ, Theriaque DW, Maldonado RC, Ilfeld BM. Effects of local anesthetic concentration and dose on continuous interscalene nerve blocks: a dual-center, randomized, observer-masked, controlled study. Reg Anesth Pain Med 2008;33:518–25
14. Ilfeld BM, Moeller LK, Mariano ER, Loland VJ, Stevens-Lapsley JE, Fleisher AS, Girard PJ, Donohue MC, Ferguson EJ, Ball ST. Continuous peripheral nerve blocks: is local anesthetic dose the only factor, or do concentration and volume influence infusion effects as well? Anesthesiology 2010;112:347–54
15. Brodner G, Buerkle H, Van Aken H, Lambert R, Schweppe-Hartenauer ML, Wempe C, Gogarten W. Postoperative analgesia after knee surgery: a comparison of three different concentrations of ropivacaine for continuous femoral nerve blockade. Anesth Analg 2007;105:256–62
16. Paauwe JJ, Thomassen BJ, Weterings J, van Rossum E, Ausems ME. Femoral nerve block using ropivacaine 0.025%, 0.05% and 0.1%: effects on the rehabilitation programme following total knee arthroplasty: a pilot study. Anaesthesia 2008;63:948–53
17. Ilfeld BM, Mariano ER, Girard PJ, Loland VJ, Meyer RS, Donovan JF, Pugh GA, Le LT, Sessler DI, Shuster JJ, Theriaque DW, Ball ST. A multicenter, randomized, triple-masked, placebo-controlled trial of the effect of ambulatory continuous femoral nerve blocks on discharge-readiness following total knee arthroplasty in patients on general orthopaedic wards. Pain 2010;150:477–84
18. Singelyn FJ, Vanderelst PE, Gouverneur JM. Extended femoral nerve sheath block after total hip arthroplasty: continuous versus patient-controlled techniques. Anesth Analg 2001;92:455–9
19. Singelyn FJ, Gouverneur JM. Extended “three-in-one” block after total knee arthroplasty: continuous versus patient-controlled techniques. Anesth Analg 2000;91:176–80
20. Eledjam JJ, Cuvillon P, Capdevila X, Macaire P, Serri S, Gaertner E, Jochum D. Postoperative analgesia by femoral nerve block with ropivacaine 0.2% after major knee surgery: continuous versus patient-controlled techniques. Reg Anesth Pain Med 2002;27:604–11
21. Lund J, Jenstrup MT, Jaeger P, Sørenson AM, Dahl JB. Continuous adductor-canal-blockade for adjuvant post-operative analgesia after major knee surgery: preliminary results. Acta Anaesthesiol Scand 2011;55:14–9
22. Kehlet, Anderson LO. Local infiltration analgesia in joint replacement: the evidence and recommendations for clinical practice. Acta Anaesthesiol Scand 2011 EPub ahead of print
23. Carli F, Clemente A, Asenjo JF, Kim DJ, Mistraletti G, Gomarasca M, Morabito A, Tanzer M. Analgesia and functional outcome after total knee arthroplasty: periarticular infiltration vs continuous femoral nerve block. Br J Anaesth 2010;105:185–95
24. Toftdahl K, Nikolajsen L, Haraldsted V, Madsen F, Tonnesen EK, Soballe K. Comparison of peri- and intraarticular analgesia with femoral nerve block after total knee arthroplasty: a randomized clinical trial. Acta Orthop 2007;78:172–9
25. Affas F, Nygards EB, Stiller CO, Wretenberg P, Olofsson C. Pain control after total knee arthroplasty: a randomized trial comparing local infiltration anesthesia and continuous femoral block. Acta Orthop 2011;82 EPub ahead of print
26. Morin AM, Kratz CD, Eberhart LH, Dinges G, Heider E, Schwarz N, Eisenhardt G, Geldner G, Wulf H. Postoperative analgesia and functional recovery after total- knee replacement: comparison of a continuous posterior lumbar plexus (psoas compartment) block, a continuous femoral nerve block, and the combination of a continuous femoral and sciatic nerve block. Reg Anesth Pain Med 2005;30:434–45
27. Ilfeld BM, Ball ST, Gearen PF, Mariano ER, Le LT, Vandenborne K, Duncan PW, Sessler DI, Enneking FK, Shuster JJ, Maldonado RC, Meyer RS. Health-related quality of life after hip arthroplasty with and without an extended-duration continuous posterior lumbar plexus nerve block: a prospective, 1-year follow-up of a randomized, triple-masked, placebo-controlled study. Anesth Analg 2009;109:586–91
28. Ilfeld BM, Meyer RS, Le LT, Mariano ER, Williams BA, Vandenborne K, Duncan PW, Sessler DI, Enneking FK, Shuster JJ, Maldonado RC, Gearen PF. Health-related quality of life after tricompartment knee arthroplasty with and without an extended-duration continuous femoral nerve block: a prospective, 1-year follow-up of a randomized, triple-masked, placebo-controlled study. Anesth Analg 2009;108:1320–5
29. Ilfeld BM, Shuster JJ, Theriaque DW, Mariano ER, Girard PJ, Loland VJ, Meyer S, Donovan JF, Pugh GA, Le LT, Sessler DI, Ball ST. Long-term pain, stiffness, and functional disability after total knee arthroplasty with and without an extended ambulatory continuous femoral nerve block: a prospective, 1-year follow-up of a multicenter, randomized, triple-masked, placebo-controlled trial. Reg Anesth Pain Med 2011;36:116–20
30. Kadic L, Boonstra MC, De Waal Malefijt MC, Lako SJ, Van Egmond J, Driessen JJ. Continuous femoral nerve block after total knee arthroplasty? Acta Anaesthesiol Scand 2009;53:914–20
31. Shum CF, Lo NN, Yeo SJ, Yang KY, Chong HC, Yeo SN. Continuous femoral nerve block in total knee arthroplasty: immediate and two-year outcomes. J Arthroplasty 2009;24:204–9