Development of technologies for placement of perineural catheters

Migration rate of proximal adductor canal block catheters placed parallel versus perpendicular to the nerve after total knee arthroplasty: a randomized controlled study

BACKGROUND

Perineural catheters placed parallel to the nerve course are reported to have lower migration rates than those placed perpendicular to it. However, catheter migration rates for a continuous adductor canal block (ACB) remain unknown. This study compared postoperative migration rates of proximal ACB catheters placed parallel and perpendicular to the saphenous nerve.

METHODS

Seventy participants scheduled for unilateral primary total knee arthroplasty were randomly assigned for parallel or perpendicular placement of the ACB catheter. The primary outcome was the migration rate of the ACB catheter on postoperative day (POD) 2. Catheter migration was defined as being unable to confirm saline administration via the catheter around the saphenous nerve at the mid-thigh level under ultrasound guidance. Secondary outcomes included active and passive range of motion (ROM) of the knee on postoperative rehabilitation.

RESULTS

Sixty-seven participants were included in the final analyses. The catheter migrated significantly less often in the parallel group (5 of 34 (14.7%)) than in the perpendicular group (24 of 33 (72.7%)) (p<0.001). The mean (SD) active and passive knee flexion ROM (degrees) improved significantly in the parallel than in the perpendicular group (POD 1: active, 88.4 (13.2) vs 80.0 (12.4), p=0.011; passive, 95.6 (12.8) vs 85.7 (13.6), p=0.004; POD 2: active, 88.7 (13.4) vs 82.2 (11.5), p=0.036; passive, 97.2 (12.8) vs 91.0 (12.0), p=0.045).

CONCLUSION

Parallel placement of the ACB catheter provided a lower postoperative catheter migration rate than perpendicular placement of the ACB catheter along with corresponding improvements in ROM and secondary analgesic outcomes.

TRIAL REGISTRATION NUMBER

UMIN000045374.

The use of extended release bupivacaine with transversus abdominis plane and subcostal anterior quadratus lumborum catheters: A retrospective analysis of a novel technique

Background and Aims

Liposomal bupivacaine (LB) is a formulation of local anesthetic that may exert analgesia over a prolonged period. Anecdotal use of LB suggests benefit and prolonged analgesia when used to supplement infiltration blocks. Our aim was to test the effect of a bolus of LB delivered through a nerve catheter in two types of interfascial plane blocks (transversus abdominis plane and anterior subcostal quadratus lumborum). The effect was evaluated through patient self-reporting of postsurgical pain up to 48 postoperative hours.

Material and Methods

Medical records of adult postoperative patients who received LB in a peripheral nerve catheter were followed retrospectively and analysed for pain scores and spread of dermatomal numbness over 48 h following the postoperative dose. A chart review of patients who qualified between June 2015 and March 2017 was performed, and clinical data were obtained from the institutional Perioperative Health Documentation System.

Results

Pain scores decreased following LB bolus, and all patients reported efficient block analgesia after bolus injection. Dermatomal numbness decreased gradually and was minimal by 48 h following bolus.

Conclusion

LB can be injected through a peripheral nerve catheter to prolong analgesia after catheter removal.

Ultrasound-Guided Continuous Femoral Nerve Block with Dexmedetomidine Combined with Low Concentrations of Ropivacaine for Postoperative Analgesia in Elderly Knee Arthroplasty

OBJECTIVES

This study aims to investigate the clinical effect of dexmedetomidine (DEX) combined with low concentrations of ropivacaine in ultrasound-guided continuous fem-oral nerve block for postoperative analgesia in elderly patients with total knee arthroplasty (TKA).

MATERIALS AND METHODS

Patients were divided into three groups: group C, group D1, and group D2. For postoperative analgesia, patients in group C were given 0.15% ropivacaine, patients in group D1 were given 0.15% ropivacaine + 0.02 μg × kg-1 × h-1 DEX, and patients in group D2 were given 0.15% ropivacaine + 0.05 μg × kg-1 × h-1 DEX. The visual analogue scores in the resting state, active state (AVAS), and passive functional exercise state (PVAS), degree of joint bending, and Ramsay scores were recorded.

RESULTS

The Ramsay scores were significantly higher, AVAS scores were significantly lower, PVAS scores were significantly decreased, the degree of joint bending was significantly higher, and the time to the first postoperative ambulation was shorter in groups D1 and D2 than group C. Furthermore, the time to the first postoperative ambulation was shorter in group D2 than in group D1, patients in groups D1 and D2 were more satisfied than patients in group C, and patients in group D2 were more satisfied than patients in group D1.

CONCLUSION

The protocol of 0.05 μg × kg-1 × h-1 of DEX combined with 0.15% ro-pivacaine in ultrasound-guided continuous femoral nerve block for postoperative analgesia in elderly patients with TKA provides a better analgesic effect than without DEX performance.

X.-Y.Z. and E.-F.Z. have contributed equally to this research.

Ultrasound guided repositioning of a new suture-method catheter for adductor canal block - a randomized pilot study in healthy volunteers

BACKGROUND

We performed a randomized, blinded pilot study in 12 volunteers to assess the feasibility to reposition an intentionally displaced suture-method catheter for two different insertion techniques for adductor canal block.

METHODS

Each volunteer had an ultrasound-guided suture-method catheter placed in the adductor canal (AC) in both legs. The catheters were placed using a perpendicular technique in one leg and a parallel technique in the other leg, according to randomization. 15 mL lidocaine 1% (LA) was injected in each catheter. Successful primary placement was defined as combined LA spread within the AC and loss of cold sensation 15 min after injection. All catheters were intentionally displaced, and subsequently repositioned using ultrasound. Another dose of lidocaine (15 mL 1%) was injected through the catheters and assessed for successful repositioning.

RESULTS

Successful primary placement was achieved in 83% (95% CI 55-95%) of catheters placed perpendicular to the AC, and in 75% (95% CI 47-91%) of catheters placed parallel to the AC. Of those with successful primary placement, 100% (95% CI 72-100%) of catheters placed perpendicular to the AC, and 67% (95% CI 35-88%)) placed parallel to the AC could be repositioned.

CONCLUSIONS

Placement and secondary repositioning after displacement of a suture-method catheter within the adductor canal is achievable. A perpendicular technique seems more reliable.

TRIAL REGISTRATION

NCT03315481 clinicaltrials.gov . The study was submitted on March 1, 2017. Due to clerical error, the study was posted on October 20, 2017.

Paths of femoral nerve catheters placed using ultrasound-guided in plane vs out of plane techniques: A randomized controlled clinical trial

BACKGROUND

Continuous blockade of the femoral nerve is widely used for postoperative analgesia after hip surgery. It can be achieved by ultrasound-guided placement of a femoral nerve catheter via either the in plane (IP) or out of plane (OOP) technique. On the basis of postoperative radiographs, we evaluated the paths of femoral nerve catheters with respect to both techniques and its effect on postoperative analgesia.

METHODS

Thirty-four patients were randomized to receive a radiopaque femoral nerve catheter via either the IP or OOP technique. The paths and tip position of the catheters were evaluated in postoperative frontal radiographs of the operated hip joint concerning a predefined target region and four neighboring regions. Pain scores were assessed using a numeric rating scale (0-10).

RESULTS

Sixteen IP patients and 18 OOP patients were included in the study. The catheter path was radiographically evaluated in 13 IP patients and in 10 OOP patients. The catheter tips were located within the target region in 39% of the IP group and in 50% of the OOP group. The catheter tip was 0.00 cm [-3.80 to 3.84] and -1.19 cm [-12.27 to 0.00] (median [range]) from the target region in the OOP group and IP group, respectively (P = .045). Catheters flipped distally more often in the IP group (IP: 61.5%, OOP: 10.0%; P = .01). There were no marked differences in the pain scores of either group.

CONCLUSION

Femoral nerve catheters inserted by the ultrasound-guided IP technique flip distally more frequently than catheters inserted by the OOP technique. Moreover, the distance between the catheter tip and the trunk of the femoral nerve is greater for IP catheters than for OOP catheters. Despite these findings, postoperative analgesia did not seem to differ between the 2 techniques.