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Extended Femoral Nerve Sheath Block After Total Hip Arthroplasty: Continuous Versus Patient-Controlled Techniques

Singelyn, François J. MD, PhD*; Vanderelst, Patrick E. MD†, and; Gouverneur, Jean-Marie A. MD*

doi: 10.1213/00000539-200102000-00033
REGIONAL ANESTHESIA AND PAIN MEDICINE: Research Report

We assessed the efficacy of patient-controlled analgesia (PCA) techniques for extended femoral nerve sheath block after total hip arthroplasty. Forty-five patients were divided into three groups of 15. Over 48 h, all patients received 0.125% bupivacaine with clonidine 1 μg/mL and sufentanil 0.1 μg/mL via a femoral nerve sheath catheter as a continuous infusion at 10 mL/h in Group 1, as PCA boluses only of 10 mL/h in Group 2, or as PCA boluses of 5 mL per 30 min in Group 3. Pain scores, sensory block, supplemental analgesia, bupivacaine consumption, side effects, and satisfaction scores were recorded. Pain scores at rest and supplemental analgesia were comparable in the three groups. At 48 h, pain relief on movement was significantly better in Group 3 than in Group 1 (P = 0.01). Bupivacaine consumption was significantly less in Groups 2 and 3 than in Group 1 (P < 0.001). Side effects were comparable in the three groups. Satisfaction scores were significantly higher in Group 3 than in the other groups (P < 0.01). We conclude that, to maintain extended femoral nerve sheath block after total hip arthroplasty, PCA techniques reduce the local anesthetic consumption without compromise in patient satisfaction or visual analog scale scores. Of the two PCA techniques tested, PCA boluses (5 mL per 30 min) of 0.125% bupivacaine with clonidine 1 μg/mL and sufentanil 0.1 μg/mL are associated with the smallest local anesthetic consumption and the most patient satisfaction.

Implications This study demonstrated that, after total hip arthroplasty, an extended femoral nerve sheath block consisting of patient-controlled analgesia boluses (5 mL per 30 min) of 0.125% bupivacaine with clonidine 1 μg/mL and sufentanil 0.1 μg/mL provides efficient postoperative analgesia and significantly minimizes local anesthetic consumption.

*Department of Anesthesiology, Université Catholique de Louvain School of Medicine, St Luc Hospital, Brussels, Belgium; and †Department of Anesthesiology, Cliniques St Pierre, Ottignies, Belgium

Presented in part at the 1997 Annual Meeting of the American Society of Anesthesiologists, San Diego, CA, October 21, 1997, and at the 1998 Annual Meeting of the International Anesthesia Research Society, Orlando, FL, March 11, 1998.

October 11, 2000.

Address correspondence and reprint requests to F.J. Singelyn, MD, PhD, Department of Anesthesiology, St Luc Hospital, Avenue Hippocrate 10/1821-B 1200, Brussels, Belgium.

Postoperative pain after total hip arthroplasty (THA) can be difficult to control. It is severe in half of patients at rest and is often exacerbated on movement or by severe reflex spasms of the quadriceps muscle (1). Postoperative pain relief can be achieved by a variety of techniques, such as IV patient-controlled analgesia (PCA) (2,3), epidural analgesia (3,4), and lumbar plexus blockade (5–7). Recently, it has been shown that extended femoral nerve sheath block provides comparable pain relief but is associated with fewer side effects and technical problems than IV PCA or patient-controlled epidural analgesia (PCEA) (6). It is therefore the preferred analgesic technique after unilateral THA.

The continuous infusion of 0.125% bupivacaine at the rate of 10 mL/h is effective to maintain extended femoral nerve sheath block (6). However, this technique leads to the administration of large volumes of local anesthetic with a potential risk of toxicity caused by accumulation of the drug after a prolonged period of infusion (8). A dose-sparing infusion technique is thus desirable. For example, after hand trauma surgery, a PCA technique via an axillary brachial plexus catheter provides good postoperative analgesia and reduces local anesthetic consumption by 70%(9). This technique has not yet been evaluated with a femoral nerve sheath catheter. The aim of the present study was to assess its efficacy after unilateral THA.

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Methods

After informed consent and with IRB approval, 45 ASA class I–III patients scheduled for elective unilateral THA under general anesthesia were included in this study. Patients were excluded if they had coagulation abnormality, were aged <18 or >80 yr, weighed <50 or >100 18 or 80 yr, weighed 50 or 100 kg, had a preexisting neurological deficit or diabetes, or were unable to understand pain scales or use a PCA device.

In all patients, a femoral nerve sheath block was performed before the induction of general anesthesia by using the landmarks of Winne et al. (10). The femoral artery was located below the inguinal ligament, and a 6-cm, 18-gauge, short-beveled, insulated needle through a plastic cannula (Alphaplex® set; Braun, Melsungen, Germany) was inserted just lateral to the artery. The femoral nerve was accurately located with a peripheral nerve stimulator (pulse duration, 40 μs; frequency, 1 Hz) (Anaestim MK III®; Meda, Antwerpen, Belgium). With a starting output of 100 nanocoulombs (nC) (2.5 mA), the needle was advanced with an angle of 30–45° to the skin until twitches of the quadriceps muscle (ascension of the patella) were elicited. Its position was then optimized and judged adequate when output lower than 40 nC (<1 mA) still elicited quadriceps contractions. By using a Seldinger technique, a 20-gauge catheter was then threaded 10–15 cm into the femoral nerve sheath. After a negative aspiration test for blood, 40 mL 0.25% bupivacaine with epinephrine 1:200,000 was injected through the catheter.

In all patients, general anesthesia was induced with 0.3 μg/kg sufentanil, 3–5 mg/kg thiopental, and 0.5 mg/kg atracurium. The trachea was intubated, and controlled ventilation was started. Anesthesia was maintained with a sufentanil infusion (0.005 μg · kg–1 · min–1 stopped approximately 45 min before the end of the procedure) and a mixture of nitrous oxide (66%) and isoflurane (0.5%–1%) in oxygen.

In all patients, ketorolac 30 mg IV was administered at the induction of general anesthesia and then three times daily during the first 48 h after surgery.

Thromboprophylaxis was given routinely with low-molecular-weight heparin, i.e., 7500 (<70 kg) or 10,000 (>70 kg) units nadroparin (Fraxiparine®; Sanofi-Winthrop, New York, NY) subcutaneously, and antiplatelet drug, i.e., 600 mg buflomédil (Loftyl®; Abbott, North Chicago, IL) PO, once daily, starting the evening of surgery.

In the recovery room, the correct position of the femoral nerve sheath catheter was confirmed by the presence of a sensory block (loss of cold sensation as assessed by using an ether-soaked swab) involving the distribution of the femoral nerve (anterior aspect of the thigh). Patients were then divided into three groups of 15 in a randomized fashion with a computer-generated list of random permutations. During the first 48 h after surgery, Group 1 received a continuous infusion of 0.125% bupivacaine with clonidine 1 μg/mL and sufentanil 0.1 μg/mL at the rate of 10 mL/h, Group 2 had PCA boluses only of 10 mL of the same solution with a lockout time of 60 min, and Group 3 had PCA boluses only of 5 mL of the same solution with a lockout time of 30 min. To blind the study, patients in Group 1 also had access to a PCA button, but it did not trigger any bolus administration.

Pain at rest and on movement (visual analog scale [VAS] ranging from 0 = no pain to 100 = worst pain imaginable) and sensory block (loss of temperature sensation assessed by using an ether-soaked swab) in the cutaneous distribution of the lateral femoral cutaneous (LFC) (lateral aspect of the thigh), femoral (anterior aspect of the thigh), and obturator (inner aspect of the knee) nerves were assessed 4, 24, and 48 h after the operation. A postoperative pain score (PPS) (0 = no pain; 1 = moderate pain only when moving; 2 = moderate pain at rest, severe pain when moving; 3 = constant severe pain) was also recorded by the nurses every 2 h during the first 12 h after surgery and then every 4 h. Supplemental postoperative analgesia was standardized. If PPS was ≥1, patients received 2 g of IV propacetamol, a derivative of paracetamol (Prodafalgan®; Upsamedica, Brussels, Belgium), followed by 10–20 mg of IM piritramide, a synthetic μ-agonist opioid (Dipidolor®; Janssen Pharmaceutica, Beerse, Belgium) if PPS remained unchanged after 30 min. Supplemental analgesia, bupivacaine consumption, side effects, and satisfaction score (with a VAS ranging from 0 = not satisfied to 100 = entirely satisfied) at the end of the study period were recorded. All data were collected by an anesthesiologist not involved in the administration of anesthesia or in patient care in the recovery room.

The patients were seen at the surgeon’s clinic 6 wk and 3 mo after the procedure. They were then asked about any adverse effects or complications.

On the basis of a previous study (11), we hypothesized that we could observe at least a 30% reduction in the consumption of bupivacaine between Groups 1 and 2. A power analysis (mean consumption of 500 [Group 1] and 350 [Group 2] mg of bupivacaine with a standard deviation of 80 mg) estimated that 10 patients would be needed in each group to provide a 95% chance of detecting such reduction at the 0.01 level of significance.

Statistical analysis was performed with the GB-Stat, version 6.5 (Dynamic Microsystems, Inc., Silver Spring, MD) computer package. Parametric data (age, weight, height, pain scores, supplemental analgesia, bupivacaine consumption, and satisfaction score) were compared by using one-way analysis of variance. Post hoc comparisons were performed with Dunnett two-tailed t-test by using Group 1 as the reference control group. PCA demands were analyzed with a Kruskal-Wallis test followed by Wilcoxon’s rank sum test for multiple comparisons. Discrete variables (sex ratio, sensory block, and side effects) were compared by using χ2(2) and Yates correction when appropriate. P < 0.05 was considered significant. Results are expressed as mean ± sd.

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Results

Population data are presented in Table 1. No statistically significant difference was noted among the groups. In the recovery room, complete loss of temperature sense in the distribution of the femoral nerve was observed in all patients.

Table 1

Table 1

The VAS scores at rest and on movement, nurse PPSs, supplemental analgesia, bupivacaine consumption, and satisfaction scores are presented in Table 2. Pain scores at rest were comparable in the three groups. When compared with Group 1, VAS on movement at 48 h was significantly lower in Group 3 (P < 0.01). Supplemental analgesia was not significantly different among the three groups. When compared with Group 1, bupivacaine consumption was significantly less in Groups 2 and 3 (P < 0.01). No difference was noted between these groups. At 48 h, satisfaction scores were significantly higher in Group 3 when compared with both other groups.

Table 2

Table 2

The use of PCA was significantly less frequent (23 ± 27, 54 ± 34, and 84 ± 109 demands per 48 h in groups 1, 2, and 3, respectively [overall P = 0.01]) in Group 1 than in both other groups (P < 0.05).

Sensory block in the cutaneous distribution of the LFC, femoral, and obturator nerves is presented in Table 3. No significant difference was noted among the groups. In the three groups, LFC and femoral nerve blocks were well maintained during the entire study period. Obturator nerve block was more evanescent, particularly in Group 2.

Table 3

Table 3

Except for nausea, vomiting, or both (3, 3, and 5 patients in groups 1, 2, and 3, respectively), no side effects or technical problems were noted in the three groups. No complication related to the analgesic technique was observed at 6 wk and 3 mo after the procedure in all patients.

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Discussion

Postoperative pain relief after THA can be achieved by a number of techniques. Because it provides a steady state of analgesia at rest, IV PCA with morphine produces better pain relief than conventional IM opioid therapy (2). However, it does not provide efficient analgesia on movement and is ineffective to prevent or relieve reflex spasms of the quadriceps muscle, which are frequent after hip surgery (12). Different studies have shown that, after hip surgery, epidural or intrathecal morphine gives superior pain relief compared with conventional IM opioids or IV PCA with morphine. However, the benefit in consistency and quality of pain control is offset by side effects, such as nausea, vomiting, pruritus, urinary retention, and a significant risk of respiratory depression (3,13). Epidural local anesthetics, with or without small doses of opioid, provide as efficient analgesia at rest as IV PCA with morphine but better analgesia on movement (4). However, local anesthetics induce some bilateral motor blockade, which makes the patient more nurse dependent, and sympathetic blockade, which requires hemodynamic monitoring.

After unilateral THA, single-dose femoral nerve block (0.5% bupivacaine 40 mL) provided better postoperative analgesia than IV PCA with morphine, but only during the first eight hours after surgery (5). Therefore, different authors have advocated the use of extended femoral nerve sheath block after such surgery (14). In a recent, large-scale (more than 1300 patients), prospective study, we demonstrated that such block is as efficient as IV PCA with morphine or PCEA. Because it induces fewer technical problems and side effects, it is presently the preferred technique (6). This study confirms the analgesic efficiency of extended femoral nerve sheath block after unilateral THA.

A continuous infusion of 0.125% bupivacaine at the rate of 0.14 mL · kg–1 · h–1 is optimal to maintain extended femoral nerve sheath block (15) : neither the extent of anesthesia nor the quality of analgesia is improved by increasing the infusion rate (16). However, this technique leads to the administration of large volumes of local anesthetic with a potential risk of toxicity caused by accumulation of the drug after prolonged periods of infusion (8). In this study, the use of PCA boluses alone provided efficient pain relief and a significant reduction (64% to 73%) in the local anesthetic consumption. Moreover, as expressed by the patients, this technique allowed rapid reinforcement of the block before a hip physiotherapy session. Of the two techniques tested, PCA boluses of five milliliters with a lockout time of 30 minutes were associated with the smallest local anesthetic consumption and the greatest patient satisfaction. It is therefore the recommended extended femoral nerve sheath block technique; however, this technique requires some time to teach the patient. The patient has to learn which pain will be relieved by the catheter (from the anesthetized area) and thus requires a PCA button push, and which pain will not be relieved by the catheter (outside the anesthetized area) and thus requires a nurse call for supplemental parenteral analgesia.

In our study, the extent of anesthesia during extended femoral nerve sheath block varied with time. Although the LFC and femoral nerve blocks were well maintained in the three groups, obturator nerve block was more evanescent, particularly at 48 hours after surgery. Similar results have been obtained by Barthelet et al. (17).

The choice of lockout intervals in our PCA groups was based on experience with PCEA. During PCEA, lockout intervals of at least 15 to 30 minutes are recommended to minimize the possibility of the patient self-administering a bolus dose before the previous dose has had time to exert its analgesic effect (18). Moreover, studies on labor pain relief have shown that the quality of analgesia is unaffected by the duration of the lockout interval as long as effective hourly doses of local anesthetic are administered (19). When considering our previous study during knee surgery (11) and the present one, we can speculate that it would be the same when using a PCA technique for continuous peripheral nerve block. However, further studies are required to confirm this statement.

In accordance with the concept of “balanced analgesia” advocated by Kehlet (20), IV ketorolac was systematically administered to all patients, and clonidine and sufentanil were included in our continuous infusion. When added to the local anesthetic solution, clonidine prolongs the duration of both anesthesia and analgesia after a single-shot brachial plexus block (21). Unpublished data support the same effects during continuous peripheral nerve block. This observation must be confirmed by a large randomized study.

In a recent metaanalysis, Picard et al. (22) concluded that there is no evidence for a clinically significant positive effect of opioids during peripheral nerve blocks. That is why, after the completion of the present study, we no longer add sufentanil to the local anesthetic solution used to maintain extended femoral nerve sheath block. No significant change in the efficiency of the technique was observed.

In this study, there were no complications attributable to the use of PCA techniques. However, the small number of patients does not permit us to make definitive conclusions about its relative safety.

In conclusion, this prospective, randomized, double-blinded study confirmed that, when associated with IV ketorolac, extended femoral nerve sheath block provides efficient pain relief after unilateral THA. It demonstrated that, compared with a continuous infusion, PCA techniques reduce the local anesthetic consumption without compromise in patient satisfaction or VAS scores. Of the two PCA techniques tested, PCA boluses of five milliliters of 0.125% bupivacaine with clonidine 1 μg/mL and sufentanil 0.1 μg/mL with a lockout time of 30 minutes were associated with the smallest local anesthetic consumption and the highest degree of patient satisfaction. It is therefore the recommended technique.

The authors are grateful to F. Veyckemans, MD, and L.J. Van Obbergh, MD, PhD, for their valuable criticism of the manuscript and their comments.

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References

1. Bonica J. Postoperative pain. In: Bonica J, ed. The management of pain. 2nd ed. Philadelphia: Lea & Febiger, 1990: 461–80.
2. Spetzler B, Anderson L. Patient-controlled analgesia in the total joint arthroplasty patient. Clin Orthop 1987; 215: 122–5.
3. Weller R, Rosenblum M, Conard P, Gross JB. Comparison of epidural and patient-controlled intravenous morphine following joint replacement surgery. Can J Anaesth 1991; 38: 582–6.
4. Bertini L, Tagariello V, Molino FM, et al. Patient-controlled postoperative analgesia in orthopedic surgery: epidural PCA versus intravenous PCA. Minerva Anestesiol 1995; 61: 319–28.
5. Fournier R, Van Gessel E, Gaggero G, et al. Postoperative analgesia with “3-in-1” femoral nerve block after prosthetic hip surgery. Can J Anaesth 1998; 45: 34–8.
6. Singelyn FJ, Gouverneur JM. Postoperative analgesia after total hip arthroplasty : IV PCA with morphine, patient-controlled epidural analgesia, or continuous “3-in-1” block: a prospective evaluation by our acute pain service in more than 1300 patients. J Clin Anesth 1999; 11: 550–4.
7. Stevens R, Van Gessel E, Flory N, et al. Lumbar plexus block reduces pain and blood loss associated with total hip arthroplasty. Anesthesiology 2000; 93: 115–21.
8. Esteve M, Veillette Y, Ecoffey C, Orhant EE. Continuous block of the femoral nerve after surgery of the knee: pharmacokinetics of bupivacaine. Ann Fr Anesth Réanim 1990; 9: 322–5.
9. Iskandar H, Rakotondriamihary S, Dixmérias F, et al. Analgesia with continuous axillary block after surgery for severe hand trauma: self-administration versus continuous injection. Ann Fr Anesth Réanim 1998; 17: 1099–103.
10. Winnie AP, Ramamurthy S, Durrani Z. The inguinal paravascular technique of lumbar plexus anesthesia: the “3-in-1” block. Anesth Analg 1973; 52: 989–96.
11. Singelyn FJ, Gouverneur JM. Extended “3-in-1” block after total knee arthroplasty: continuous vs patient-controlled techniques. Anesth Analg 2000; 91: 176–80.
12. Bonica J. Painful disorders of the thigh and knee. In: Bonica J, ed. The management of pain. 2nd ed. Philadelphia: Lea & Febiger, 1990: 1557–84.
13. Niemi L, Pitkänen M, Tuominen M, Rosenberg PH. Comparison of intrathecal fentanyl infusion with intrathecal morphine infusion or bolus for postoperative pain relief after hip arthroplasty. Anesth Analg 1993; 77: 126–30.
14. Striebel HW, Wilker E. Postoperative pain therapy following total endoprosthetic surgery on the hip using a continuous 3-in-1 blockade. Anasthesiol Intensivmed Notfallmed Schmerzther 1993; 28: 168–73.
15. Anker-Møller E, Spansberg N, Dahl JB, et al. Continuous blockade of the lumbar plexus after knee surgery: a comparison of the plasma concentrations and analgesic effect of bupivacaine 0.250% and 0.125%. Acta Anaesthesiol Scand 1990; 34: 468–72.
16. Van der Elst P, Singelyn F. Influence of different infusion rates on postoperative analgesic efficacy of continuous “3-in-1” block (CB) after total hip replacement [abstract]. Anesthesiology 1997; 87: A776.
17. Barthelet Y, Capdevila X, Bernard N, et al. Continuous analgesia with a femoral catheter: plexus or femoral nerve blockade? Ann Fr Anesth Réanim 1998; 17: 1199–205.
18. Marlowe S, Engstrom R, White P. Epidural patient-controlled analgesia (PCA): an alternative to continuous epidural infusions. Pain 1989; 37: 97–101.
19. Gambling D, Huber C, Berkowitz J, et al. Patient-controlled epidural analgesia in labour: varying bolus dose and lockout interval. Can J Anaesth 1993; 40: 211–7.
20. Kehlet H. Surgical stress: the role of pain and analgesia. Br J Anaesth 1989; 63: 189–95.
21. Singelyn F, Gouverneur JM, Robert A. A minimum dose of clonidine added to mepivacaine prolongs the duration of anesthesia and analgesia after axillary brachial plexus block. Anesth Analg 1996; 83: 1046–50.
22. Picard P, Tramèr M, McQuay H, Moore R. Analgesic efficacy of peripheral opioids (all except intra-articular): a qualitative systematic review of randomised controlled trials. Pain 1997; 72: 309–18.
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