A randomized comparison of long-and short-axis imaging for in-plane ultrasound-guided femoral perineural catheter insertion

Proximal versus distal adductor canal blocks for total knee arthroplasty: A protocol for randomized controlled trial

BACKGROUND

Currently, there remains a paucity of literature about the efficiency of proximal adductor canal block (PACB) versus distal adductor canal block (DACB) for pain management after total knee arthroplasty (TKA). The purpose of this study is to perform a randomized controlled trial to compare the efficiency of PACB versus DACB for early postoperative pain treatment after TKA.

METHODS

This study is a 2-arm, parallel-group, randomized controlled trial that is conducted at a single university hospital in China. Subjects presenting for unilateral TKA are randomized in a 1:1 ratio to either a PACB or DACB group. The primary outcome of this noninferiority study is opioid consumption within the first 24 hours following surgery. Secondary outcomes include quadriceps strength, pain scores, distance ambulated, and patient satisfaction. Continuous variables are compared using Student t test.

RESULTS

This clinical trial is expected to provide evidence of whether the PACB and DACB provide similar analgesia after TKA.

TRIAL REGISTRATION

This study protocol was registered in Research Registry (researchregistry5440).

Multiple versus single doses of dexamethasone in total hip arthroplasty: A protocol of randomized controlled trial

BACKGROUND

Reduction of post-operative pain, nausea, and vomiting in patients undergoing total hip arthroplasty (THA) may facilitate earlier discharge from hospital and reduce healthcare costs. The recommended dose regimen of dexamethasone in THA has not been determined. The purpose of this study was performed to compare the efficiency of multiple versus single doses of dexamethasone for early postoperative pain treatment after THA.

METHODS

This study was a randomized controlled trial which conducted in our hospital. Informed consent for participation in this trial was obtained from each patient before surgery. Two hundred patients undergoing THA received 1 dose of intravenous dexamethasone and 1 dose of normal saline (Group A), or 2 doses of intravenous dexamethasone (Group B). The primary outcome was visual analog scale pain scores in the immediate postoperative period. Secondary outcomes included postoperative opioid use, length of hospital stay, activity level during physical therapy, and hip range of motion.

RESULTS

This clinical trial might provide some insights to estimate the safety of dexamethasone.

TRIAL REGISTRATION

This study protocol was registered in Research Registry (researchregistry5460).

Peripheral nerve catheters: A critical review of the efficacy

Continuous peripheral nerve blocks are commonly used for postoperative analgesia after surgery. However, catheter failure may occur due to either primary (incorrect insertion) or secondary reasons (displacement, obstruction, disconnection). Catheter failure results in unanticipated pain, need for opioid use, and risk of readmission or delay in hospital discharge. This review aimed to assess definition and frequency of catheter failure, and discuss the alternatives to prolong duration of single-shot nerve blocks. A literature search was performed on peripheral catheters reporting failure as the main outcome measure. Thirty-three studies met the selection criteria, comprising 2711 catheters. Literature review suggests that peripheral nerve catheters have clinically significant failure rate when the assessment is performed using an objective (imaging) method. Subjective methods of assessment (without imaging) may underestimate the incidence of catheter failure.

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.

Pediatric Ambulatory Continuous Peripheral Nerve Blocks

Despite the widespread use of ambulatory continuous peripheral nerve blocks in adults, its use in children has been sporadic. Indications for the use of ambulatory continuous peripheral nerve block in children involve orthopedic procedure, where significant pain is anticipated beyond 24 hours. Techniques to place the perineural catheters in children are similar to that used in adults. The incidence of serious side effects in pediatric ambulatory continuous peripheral nerve block is extremely rare. When this is combined with the potential to increase patient and family satisfaction and decrease opioid-related side effects, ambulatory continuous peripheral nerve block become a compelling choice.

Deep and superficial circumflex iliac arteries and their relationship to the ultrasound-guided femoral nerve block procedure: A cadaver study

The in-plane lateral to medial approach is a standard technique for ultrasound-guided femoral nerve block (USG-FNB). The first bifurcation of the femoral artery, which consists of the deep artery of the thigh (DAT) or occasionally the lateral circumflex femoral artery (LCFA), is regarded as the distal border for this procedure. We sometimes detect arteries along the estimated needle trajectory for USG-FNB. The superficial (SCIA) and deep (DCIA) circumflex iliac arteries run laterally parallel to the inguinal ligament from the femoral or external iliac artery. The relationship between the SCIA and DCIA and other anatomical structures related to USG-FNB around the femoral triangle region was studied by gross anatomical examination of 100 formalin-fixed adult cadavers. At least one SCIA and one DCIA were identified around each femoral triangle; 81.8% of SCIA and 58% of DCIA originated from the femoral artery. All DCIA coursed between the fascia lata and fascia iliaca and 80% of SCIA penetrated the fascia lata. In 94% of femoral triangles, at least one arterial branch heading towards the lateral part of the thigh originated from the femoral artery from the level of the inguinal ligament to the first bifurcation of the femoral artery. The presence of SCIA and DCIA should be considered during USG-FNB using the in-plane lateral to medial approach to avoid inadvertently injuring them, as they are occasionally located along the presumed needle trajectory superficial to the fascia iliaca. Clin. Anat. 30:413-420, 2017. © 2017 Wiley Periodicals, Inc.

Randomized comparison of popliteal-sciatic perineural catheter tip migration and dislocation in a cadaver model using two catheter designs

BACKGROUND

New catheter-over-needle (CON) technology for continuous peripheral nerve blockade has emerged, but its effect on the risk of perineural catheter tip dislocation is unknown. Less flexible catheters may be more likely to migrate away from the nerve with simulated patient movement. In the present study, we evaluated catheter tip migration between CON catheters and traditional catheter-through-needle (CTN) catheters during ultrasound-guided short-axis in-plane (SAX-IP) insertion.

METHODS

We evaluated the migration of popliteal-sciatic catheters in a prone, unembalmed male cadaver. Thirty catheter placement trials were divided randomly into two groups based on the catheter type: CON or CTN. A single anesthesiology resident placed the catheters by SAX-IP insertion, and the catheters were then examined by ultrasound before and after ipsilateral knee range of motion (ROM) exercises (0°-130° flexion). A blinded expert regional anesthesiologist performed caliper measurements on the ultrasound images before and after the ROM exercises. The primary outcome was the change in distance from the catheter tip to the center of the nerve (cm) between before and after the ROM exercises.

RESULTS

The change in the tip-to-nerve distance (median [10th-90th percentile]) was 0.06 (-0.16 to 0.23) cm for the CTN catheter and 0.00 (-0.12 to 0.69) for the CON catheter (P = 0.663). However, there was a statistically significant increase in dislocation out of the nerve compartment for the CON catheter (4/15; 0/15 for CTN) (P = 0.043).

CONCLUSIONS

Although the use of different catheter designs had no effect on the change in the measured migration distance of popliteal-sciatic catheters, 27% of the CON catheters were dislocated out of the nerve compartment. These results may influence the choice of catheter design when using SAX-IP perineural catheter insertion.

Can bedside patient-reported numbness predict postoperative ambulation ability for total knee arthroplasty patients with nerve block catheters?

BACKGROUND

Adductor canal catheters offer advantages over femoral nerve catheters for knee replacement patients because they produce less quadriceps muscle weakness; however, applying adductor canal catheters in bedside clinical practice remains challenging. There is currently no patient-reported outcome that accurately predicts patients' physical function after knee replacement. The present study evaluates the validity of a relatively new patient-reported outcome, i.e., a numbness score obtained using a numeric rating scale, and assesses its predictive value on postoperative ambulation.

METHODS

We conducted a retrospective cohort study pooling data from two previously-published clinical trials using identical research methodologies. Both studies recruited patients undergoing knee replacement; one studied adductor canal catheters while the other studied femoral nerve catheters. Our primary outcome was patient-reported numbness scores on postoperative day 1. We also examined postoperative day 1 ambulation distance and its association with postoperative numbness using linear regression, adjusting for age, body mass index, and physical status.

RESULTS

Data from 94 subjects were included (femoral subjects, n = 46; adductor canal subjects, n = 48). Adductor canal patients reported decreased numbness (median [10(th)-90(th) percentiles]) compared to femoral patients (0 [0-5] vs. 4 [0-10], P = 0.001). Adductor canal patients also ambulated seven times further on postoperative day 1 relative to femoral patients. There was a significant association between postoperative day 1 total ambulation distance and numbness (Beta = -2.6; 95% CI: -4.5, -0.8, P = 0.01) with R(2) = 0.1.

CONCLUSIONS

Adductor canal catheters facilitate improved early ambulation and produce less patient-reported numbness after knee replacement, but the correlation between these two variables is weak.

Comparative effectiveness of infraclavicular and supraclavicular perineural catheters for ultrasound-guided through-the-catheter bolus anesthesia

OBJECTIVES

Using a through-the-needle local anesthetic bolus technique, ultrasound-guided infraclavicular perineural catheters have been shown to provide greater analgesia compared to supraclavicular catheters. A through-the-catheter bolus technique, which arguably "tests" the anesthetic efficacy of the catheter before initiating an infusion, has been validated for infraclavicular catheters but not supraclavicular catheters. This study investigated the through-the-catheter bolus technique for supraclavicular catheters and tested the hypothesis that infraclavicular catheters provide faster onset of brachial plexus anesthesia.

METHODS

Preoperatively, patients were randomly assigned to receive either a supraclavicular or an infraclavicular catheter using an ultrasound-guided nonstimulating catheter insertion technique with a mepivacaine bolus via the catheter and ropivacaine perineural infusion initiated postoperatively. The primary outcome was time to achieve complete sensory anesthesia in the ulnar and median nerve distributions. Secondary outcomes included procedural time, procedure-related pain and complications, and postoperative pain, opioid consumption, sleep disturbances, and motor weakness.

RESULTS

Fifty patients were enrolled in the study; all but 2 perineural catheters were successfully placed per protocol. Twenty-one of 24 (88%) and 24 of 24 (100%) patients in the supraclavicular and infraclavicular groups, respectively, achieved complete sensory anesthesia by 30 minutes (P= .088). There was no difference in the time to achieve complete sensory anesthesia. Supraclavicular patients reported more sleep disturbances postoperatively, but there were no statistically significant differences in other outcomes.

CONCLUSIONS

Both supraclavicular and infraclavicular perineural catheters using a through-the-catheter bolus technique provide effective brachial plexus anesthesia.

A pilot in vitro evaluation of the "air test" for perineural catheter tip localization by a novice regional anesthesiologist

The "air test" is used clinically to infer perineural catheter location and has been recently evaluated for use by experts. However, its utility for practitioners with less experience is unknown. We tested the hypothesis that the air test, when performed by a novice regional anesthesiologist, will improve assessment of perineural catheter tip position in a validated porcine-bovine model and determined the test's positive and negative predictive values, sensitivity, and specificity for a novice. In contrast to the results of the expert study, the air test did not improve the novice's assessment of perineural catheter tip location over chance.

Evidence-based medicine for ultrasound-guided regional anesthesia

Available evidence favoring the use of ultrasound for regional anesthesia is reviewed, updated, and critically assessed. Important outcome advantages include decreased time to block onset; decreased risk of local anesthetic systemic toxicity; and, depending on the outcome definition, increased block success rates. Ultrasound guidance, peripheral nerve blocks, and central neuraxial blocks are discussed.

A randomized comparison of proximal and distal ultrasound-guided adductor canal catheter insertion sites for knee arthroplasty

OBJECTIVES

Proximal and distal (mid-thigh) ultrasound-guided continuous adductor canal block techniques have been described but not yet compared, and infusion benefits or side effects may be determined by catheter location. We hypothesized that proximal placement will result in faster onset of saphenous nerve anesthesia, without additional motor block, compared to a distal technique.

METHODS

Preoperatively, patients receiving an ultrasound-guided nonstimulating adductor canal catheter for knee arthroplasty were randomly assigned to either proximal or distal insertion. A local anesthetic bolus was administered via the catheter after successful placement. The primary outcome was the time to achieve complete sensory anesthesia in the saphenous nerve distribution. Secondary outcomes included procedural time, procedure-related pain and complications, postoperative pain, opioid consumption, and motor weakness.

RESULTS

Proximal insertion (n = 23) took a median (10th-90th percentiles) of 12.0 (3.0-21.0) minutes versus 6.0 (3.0-21.0) minutes for distal insertion (n = 21; P= .106) to anesthetize the medial calf. Only 10 of 25 (40%) and 10 of 24 (42%) patients in the proximal and distal groups, respectively, developed anesthesia at both the medial calf and top of the patella (P= .978). Bolus-induced motor weakness occurred in 19 of 25 (76%) and 16 of 24 (67%) patients in the proximal and distal groups (P = .529). Ten of 24 patients (42%) in the distal group required intravenous morphine postoperatively, compared to 2 of 24 (8%) in the proximal group (P = .008), but there were no differences in other secondary outcomes.

CONCLUSIONS

Continuous adductor canal blocks can be performed reliably at both proximal and distal locations. The proximal approach may offer minor analgesic and logistic advantages without an increase in motor block.

Real-time sonographically guided percutaneous dilatational tracheostomy using a long-axis approach compared to the landmark technique

OBJECTIVES

Sonographic evaluation of neck anatomy before performing percutaneous dilatational tracheostomy (PDT) has been shown to predict PDT success. In this study, we compared the real-time, long-axis, in-plane approach to the traditional bronchoscopically guided landmark technique.

METHODS

Data were analyzed from a prospectively maintained PDT database at a university tertiary care medical intensive care unit. A convenience sample of adult patients requiring PDT for prolonged mechanical ventilation dependence was enrolled. Critical care fellows, under direct supervision of an attending intensivist, performed all PDTs. Tracheostomy performance from the sonographically guided and landmark techniques was compared.

RESULTS

Twenty-three patients were enrolled: 11 in the sonography group and 12 in the landmark group. Initial midline introducer needle puncture was achieved in 72.7% in the sonography group compared to 8.3% in the landmark group (P< .001). The mean number of introducer needle punctures ± SD was significantly lower in the sonography group compared to the landmark group (1.4 ± 0.7 versus 2.6 ± 0.9; P < .001). The total tracheostomy time was 11.4 ± 4.2 minutes in the sonography group versus 15.3 ± 6.8 minutes in the landmark group (P = .12). Sonography accurately predicted tracheal ring space insertion in 90.9% of patients. Procedural complications did not differ significantly between the groups.

CONCLUSIONS

Percutaneous dilatational tracheostomy under real-time sonographic guidance using a long-axis approach may increase the rate of midline punctures and decrease the number of needle punctures when compared to the landmark technique. Sonographic guidance can also help guide accurate and efficient placement of a tracheostomy tube into the desired tracheal ring space.

Continuous adductor canal blocks are superior to continuous femoral nerve blocks in promoting early ambulation after TKA

BACKGROUND

Femoral continuous peripheral nerve blocks (CPNBs) provide effective analgesia after TKA but have been associated with quadriceps weakness and delayed ambulation. A promising alternative is adductor canal CPNB that delivers a primarily sensory blockade; however, the differential effects of these two techniques on functional outcomes after TKA are not well established.

QUESTIONS/PURPOSES

We determined whether, after TKA, patients with adductor canal CPNB versus patients with femoral CPNB demonstrated (1) greater total ambulation distance on Postoperative Day (POD) 1 and 2 and (2) decreased daily opioid consumption, pain scores, and hospital length of stay.

METHODS

Between October 2011 and October 2012, 180 patients underwent primary TKA at our practice site, of whom 93% (n = 168) had CPNBs. In this sequential series, the first 102 patients had femoral CPNBs, and the next 66 had adductor canal CPNBs. The change resulted from a modification to our clinical pathway, which involved only a change to the block. An evaluator not involved in the patients' care reviewed their medical records to record the parameters noted above.

RESULTS

Ambulation distances were higher in the adductor canal group than in the femoral group on POD 1 (median [10(th)-90(th) percentiles]: 37 m [0-90 m] versus 6 m [0-51 m]; p < 0.001) and POD 2 (60 m [0-120 m] versus 21 m [0-78 m]; p = 0.003). Adjusted linear regression confirmed the association between adductor canal catheter use and ambulation distance on POD 1 (B = 23; 95% CI = 14-33; p < 0.001) and POD 2 (B = 19; 95% CI = 5-33; p = 0.008). Pain scores, daily opioid consumption, and hospital length of stay were similar between groups.

CONCLUSIONS

Adductor canal CPNB may promote greater early postoperative ambulation compared to femoral CPNB after TKA without a reduction in analgesia. Future randomized studies are needed to validate our major findings.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Application of echogenic technology for catheters used in ultrasound-guided continuous peripheral nerve blocks

Limited data exist regarding the echogenicity of perineural catheters, but visualization is crucial to ensure accurate placement and efficacy of the subsequent local anesthetic infusion. The objective of this study was to determine the comparative echogenicity of various regional anesthesia catheters. In an in vitro porcine-bovine model, we compared the echogenic qualities of 3 commercially available regional anesthesia catheters and 1 catheter under development to optimize echogenicity. Outcomes included visual echogenicity ranking, image quality, and scanning time, as assessed by 2 blinded investigators. The experimental catheter was found to be more echogenic than 2 of the 3 comparators.