Continuous femoral nerve analgesia after unilateral total knee arthroplasty: stimulating versus nonstimulating catheters

Assessing outcome in postoperative pain trials: are we missing the point? A systematic review of pain-related outcome domains reported in studies early after total knee arthroplasty

ABSTRACT

The management of acute postoperative pain remains suboptimal. Systematic reviews and Cochrane analysis can assist with collating evidence about treatment efficacy, but the results are limited in part by heterogeneity of endpoints in clinical trials. In addition, the chosen endpoints may not be entirely clinically relevant. To investigate the endpoints assessed in perioperative pain trials, we performed a systematic literature review on outcome domains assessing effectiveness of acute pain interventions in trials after total knee arthroplasty. We followed the Cochrane recommendations for systematic reviews, searching PubMed, Cochrane, and Embase, resulting in the screening of 1590 potentially eligible studies. After final inclusion of 295 studies, we identified 11 outcome domains and 45 subdomains/descriptors with the domain "pain"/"pain intensity" most commonly assessed (98.3%), followed by "analgesic consumption" (88.8%) and "side effects" (75.3%). By contrast, "physical function" (53.5%), "satisfaction" (28.8%), and "psychological function" (11.9%) were given much less consideration. The combinations of outcome domains were inhomogeneous throughout the studies, regardless of the type of pain management investigated. In conclusion, we found that there was high variability in outcome domains and inhomogeneous combinations, as well as inconsistent subdomain descriptions and utilization in trials comparing for effectiveness of pain interventions after total knee arthroplasty. This points towards the need for harmonizing outcome domains, eg, by consenting on a core outcome set of domains which are relevant for both stakeholders and patients. Such a core outcome set should include at least 3 domains from 3 different health core areas such as pain intensity, physical function, and one psychological domain.

Lower extremity regional anesthesia: essentials of our current understanding

The advent of ultrasound guidance has led to a renewed interest in regional anesthesia of the lower limb. In keeping with the American Society of Regional Anesthesia and Pain Medicine's ongoing commitment to provide intensive evidence-based education, this article presents a complete update of the 2005 comprehensive review on lower extremity peripheral nerve blocks. The current review article strives to (1) summarize the pertinent anatomy of the lumbar and sacral plexuses, (2) discuss the optimal approaches and techniques for lower limb regional anesthesia, (3) present evidence to guide the selection of pharmacological agents and adjuvants, (4) describe potential complications associated with lower extremity nerve blocks, and (5) identify informational gaps pertaining to outcomes, which warrant further investigation.

Continuous Femoral Nerve Blockade versus Epidural Analgesia for Postoperative Pain Relief in Knee Surgeries: A Randomized Controlled Study

Background:

Peripheral neural blockade provides effective analgesia with potentially less side effects than an epidural blockade. The present study was undertaken to compare continuous femoral nerve blockade (CFNB) with continuous epidural analgesia (CEA) for postoperative pain control in knee surgeries.

Materials and Methods:

The patients belonging to the American Society of Anesthesiologists Class I and II scheduled for various knee surgeries under spinal anesthesia were enrolled in this study. They were randomly divided into two equal groups of thirty patients each. The Group I patients received CFNB and in the Group II patients epidural catheter was placed preoperatively. Postoperatively, continuous infusion with 0.0625% bupivacaine and fentanyl 2 μg/ml started at 5 ml/h for 72 h in both the groups. Data on Visual Analog Scale (VAS) pain scores, hemodynamic changes, side effects at 0, 1, 6, 12, 24, 36, 48, 60, and 72 h and requirement of analgesic doses for the first 24 h of the surgery were noted.

Results:

In both the groups, pain was well controlled, mean VAS of pain were 0.2, 0.6, 2.47, 2.07, 2.73, 1.5, 1.43, 1.37, and 1.3 for femoral and 0.13, 0.93, 2.57, 2.17, 2.33, 1.6, 1.43, 1.30, and 1.33 for epidural group during 0, 1, 6, 12, 24, 36, 48, 60, and 72 h which was not statistically significant. Hemodynamics were stable throughout in both the groups. The patients in CEA had more incidences of pruritus and urinary retention.

Conclusion:

CFNB provides postoperative analgesia equivalent to that obtained with a CEA but with fewer side effects.

The role of continuous peripheral nerve blocks

A continuous peripheral nerve block (cPNB) is provided in the hospital and ambulatory setting. The most common use of CPNBs is in the peri- and postoperative period but different indications have been described like the treatment of chronic pain such as cancer-induced pain, complex regional pain syndrome or phantom limb pain. The documented benefits strongly depend on the analgesia quality and include decreasing baseline/dynamic pain, reducing additional analgesic requirements, decrease of postoperative joint inflammation and inflammatory markers, sleep disturbances and opioid-related side effects, increase of patient satisfaction and ambulation/functioning improvement, an accelerated resumption of passive joint range-of-motion, reducing time until discharge readiness, decrease in blood loss/blood transfusions, potential reduction of the incidence of postsurgical chronic pain and reduction of costs. Evidence deriving from randomized controlled trials suggests that in some situations there are also prolonged benefits of regional anesthesia after catheter removal in addition to the immediate postoperative effects. Unfortunately, there are only few data demonstrating benefits after catheter removal and the evidence of medium- or long-term improvements in health-related quality of life measures is still lacking. This review will give an overview of the advantages and adverse effects of cPNBs.

[Influence of femoral catheter stimulation intensity on post-surgical analgesia after total knee replacement]

INTRODUCTION

Stimulating catheters allow the catheter point to be positioned near the nerve, thus reducing the amount of local anaesthetic required for a successful block. There is currently a debate on what is the stimulation intensity required to provide adequate analgesia, although it does seem that if it is obtained with 1mAmp or less the block is more effective. The objective of the study was to demonstrate whether different neurostimulation intensities with the stimulating catheter at femoral nerve level, had an influence on the adequacy of post-surgical analgesia during the 48h after total knee arthroplasty.

MATERIAL AND METHODS

A comparative, prospective and randomised study was conducted on patients subjected to total knee replacement. After surgery with subarachnoid anaesthesia, a continuous femoral block was performed with a stimulating catheter at a neurostimulation intensity 0.2 and 0.5mAmp in Group 1, between 0.6 and 1mAmp in Group 2, equal or higher than 1.1mAmp in Group 3, and in Group 4 the catheter was introduced between 3-5cm without looking for a motor response. A dose of 0.2% ropivacaine 0.4mL/kg and an infusion at 5mL/h, with boluses of 10mL/30min, was administered via the catheter. Sciatic nerve block was also performed on all patients with 20ml of 0.5% ropivacaine. The patient demographics were recorded, as well as, post-surgical analgesia details, sensory and motor block in each area, boluses requested, rescue analgesia, and undesirable effects at 8, 16, 24, 36 and 48h.

RESULTS

A total of 124 patients were included, 32 in Group 1 (25.8%), 21 in Group 2 (16.9%), 31 in Group 3 (25%), and 40 in group 4 (32.3%). The 4 groups were homogeneous as regards age, height, weight and ASA. There were no statistically significant differences found in the post-operative pain, except during movement in the femoral area at 36 hours (p=.032). There were also no statistically significant differences found in the sensory block in the femoral area at 48 hours (p=.019) and in the femoral cutaneous nerve block at 8 hours (p=.049) or at 24 hours (p=.045). As regards motor block, differences were only found in the obturator nerve at 24 hours (p=.016). There were no differences in rescue analgesia, patient controlled analgesia (PCA) boluses requested or administered, except that the number of boluses requested at 16 hours was less in Group 3 (p=.049). There were also no significant differences in undesirable effects or in the level of satisfaction of the patients between the four groups.

CONCLUSIONS

In our study, no influence was found on the level of analgesia provided after knee replacement surgery with the neurostimulation intensity to which the neuromuscular system involved responded when a stimulating catheter is inserted at femoral level.

Low cost continuous femoral nerve block for relief of acute severe cancer related pain due to pathological fracture femur

Pathological fractures in cancer patient cause severe pain that is difficult to control pharmacologically. Even with good pain relief at rest, breakthrough and incident pain can be unmanageable. Continuous regional nerve blocks have a definite role in controlling such intractable pain. We describe two such cases where severe pain was adequately relieved in the acute phase. Continuous femoral nerve block was used as an efficient, cheap and safe method of pain relief for two of our patients with pathological fracture femur. This method was proved to be quite efficient in decreasing the fracture-related pain and improving the level of well being.

Continuous femoral versus posterior lumbar plexus nerve blocks for analgesia after hip arthroplasty: a randomized, controlled study

BACKGROUND

Hip arthroplasty frequently requires potent postoperative analgesia, often provided with an epidural or posterior lumbar plexus local anesthetic infusion. However, American Society of Regional Anesthesia guidelines now recommend against epidural and continuous posterior lumbar plexus blocks during administration of various perioperative anticoagulants often administered after hip arthroplasty. A continuous femoral nerve block is a possible analgesic alternative, but whether it provides comparable analgesia to a continuous posterior lumbar plexus block after hip arthroplasty remains unclear. We therefore tested the hypothesis that differing the catheter insertion site (femoral versus posterior lumbar plexus) after hip arthroplasty has no impact on postoperative analgesia.

METHODS

Preoperatively, subjects undergoing hip arthroplasty were randomly assigned to receive either a femoral or a posterior lumbar plexus stimulating catheter inserted 5 to 15 cm or 0 to 1 cm past the needle tip, respectively. Postoperatively, patients received perineural ropivacaine, 0.2% (basal 6 mL/hr, bolus 4 mL, 30-minute lockout) for at least 2 days. The primary end point was the average daily pain scores as measured with a numeric rating scale (0-10) recorded in the 24-hour period beginning at 07:30 the morning after surgery, excluding twice-daily physical therapy sessions. Secondary end points included pain during physical therapy, ambulatory distance, and supplemental analgesic requirements during the same 24-hour period, as well as satisfaction with analgesia during hospitalization.

RESULTS

The mean (SD) pain scores for subjects receiving a femoral infusion (n = 25) were 3.6 (1.8) versus 3.5 (1.8) for patients receiving a posterior lumbar plexus infusion (n = 22), resulting in a group difference of 0.1 (95% confidence interval -0.9 to 1.2; P = 0.78). Because the confidence interval was within a prespecified -1.6 to 1.6 range, we conclude that the effect of the 2 analgesic techniques on postoperative pain was equivalent. Similarly, we detected no differences between the 2 treatments with respect to the secondary end points, with one exception: subjects with a femoral catheter ambulated a median (10th-90th percentiles) 2 (0-17) m the morning after surgery, in comparison with 11 (0-31) m for subjects with a posterior lumbar plexus catheter (data nonparametric; P = 0.02).

CONCLUSIONS

After hip arthroplasty, a continuous femoral nerve block is an acceptable analgesic alternative to a continuous posterior lumbar plexus block when using a stimulating perineural catheter. However, early ambulatory ability suffers with a femoral infusion.

The effect of stimulating versus nonstimulating catheter techniques for continuous regional anesthesia: a semiquantitative systematic review

BACKGROUND AND OBJECTIVES

Stimulating catheters provide feedback regarding the location of the catheter tip in relation to the target nerve or plexus. There is debate concerning whether stimulating catheters may reduce the failure rate of postoperative analgesia or whether they may enhance functional recovery by providing superior and more reliable postoperative analgesia.

METHODS

Studies comparing the effect of stimulating versus nonstimulating catheters for postoperative analgesia were systematically and independently searched by 2 authors.

RESULTS

Eleven randomized controlled studies could be included in this review. One trial was performed in volunteers; the others were clinical trials in patients. Five trials were performed in patients scheduled for a femoral nerve catheter, 4 for a distal sciatic nerve catheter, 1 in patients receiving an interscalene nerve catheter, and 1 in patients with an infraclavicular brachial plexus block. A standard quantitative analysis was deemed inappropriate because of considerable heterogeneity regarding the investigated outcome parameters. A semiquantitative review revealed that efficacy (judged by reduction in the need for rescue analgesics, complete surgery block, or median effective local anesthetic volume blocking the nerve) suggests improvement in stimulating catheters compared with nonstimulating catheters. Patient satisfaction as well as functional recovery was poorly investigated, so no conclusions could be drawn.

CONCLUSIONS

Published reports of randomized controlled trials provide evidence for a better analgesic effect from stimulating catheters. Future trials should be conducted in a standardized manner with uniform reporting of outcomes, which may facilitate future quantitative analysis.

Ambulatory anesthesia and regional catheters: when and how

Several clinical trials have demonstrated the superiority of continuous peripheral nerve block compared with traditional opioid-based analgesia. The ability to provide safe and effective continuous peripheral nerve block at home is an attractive alternative to opioid-based analgesia with its related side effects. In this article, the practical issues related to catheter use in the ambulatory setting are discussed. Techniques for catheter placement, infusion regimens, patient education, and complications are subject to many institutional preferences. In this review, special emphasis is placed on evidence-based techniques.

[Pain therapy using stimulating catheters after total knee arthroplasty]

BACKGROUND

Epidural analgesia and continuous femoral nerve blocks are often used for pain therapy after total knee arthroplasty. The additional use of a continuous sciatic nerve block is controversially discussed. To avoid the problem of inaccurate placement a stimulating catheter may be useful. The aim of this study was to compare the effectiveness of a continuous femoral nerve block with an additional continuous sciatic nerve block for improved functional recovery and pain relief.

MATERIAL AND METHODS

An open randomized prospective controlled study was carried out with 54 patients to receive either a stimulating catheter placed in the femoral nerve sheath or two stimulating catheters placed in the femoral and in the sciatic nerve sheath or an epidural analgesia. Pain was recorded with the visual analogue scale at rest and with passive motion of the knee during the first 3 postoperative days. The angle of nearly pain-free bending of the knee, side effects and opioid consumption were recorded.

RESULTS

The reported pain scores and opioid consumption did not differ significantly between the groups. However, functional recovery up to the third postoperative day was significantly worse in the femoral catheter group.

CONCLUSION

Using stimulating catheters for pain therapy the three methods are largely comparable and other parameters should be used for individual selection.

Continuous peripheral nerve blocks in clinical practice

PURPOSE OF REVIEW

The present review highlights new insights into indications and guidance during procedures for continuous peripheral nerve blocks.

RECENT FINDINGS

Continuous peripheral nerve blocks consistently provide better analgesia than traditional systemic opioid-based analgesia. The literature shows that continuous peripheral nerve blocks prolong site-specific local anesthetic delivery in the outpatient setting, allow optimal analgesia, have minimal side effects, and avoid premature regression of an analgesic block. Furthermore, an improvement in patients' health-related quality of life or outcome benefits has been demonstrated. It appears that continuous peripheral nerve blocks are generally superior to intraarticular local anesthetic infusion for immediate postoperative pain, but new data demonstrate that, apart from a multimodal analgesia regimen, periarticular and intraarticular application of local anesthetics can improve early postoperative analgesia and mobilization. Finally, it seems that, only for interscalene and popliteal sciatic nerve blocks, the use of stimulating catheters slightly decreases visual analog scale scores for postoperative pain and intravenous opioid rescue analgesia. Ultrasound guidance offers the potential advantage to confirm catheter tip location.

SUMMARY

Continuous peripheral nerve blocks are essential in the perioperative anesthetic management of in-hospital or ambulatory patients. Ultrasound guidance and stimulating catheters can help anesthetists during the procedure.