Continuous basal infusion versus programmed intermittent bolus for quadratus lumborum block after laparoscopic colorectal surgery: a randomized-controlled, double-blind study.

BACKGROUND: Quadratus lumborum block (QLB) has recently attracted attention as a part of multimodal analgesia after abdominal surgery. It has been shown that programmed intermittent boluses of local anesthetic can produce better analgesia and wider sensory blockade compared with continuous basal infusion with some peripheral nerve blocks. The present study was conducted to see if this theory holds true for QLB in patients undergoing laparoscopic colorectal surgery. METHODS: Fifty patients undergoing laparoscopic colorectal surgery were divided into 2 groups to receive continuous basal infusion (group C) or programmed intermittent boluses (group PIB) of local anesthetic. After surgery, patients received the posterior approach to QLB and a catheter was introduced bilaterally. Patients in group C received a continuous infusion of 0.15% levobupivacaine at 3 ml/h, and those in group PIB received a bolus of 12 ml every 4 h. All patients received intravenous patient-controlled analgesia using fentanyl. Measurements were taken for cumulative fentanyl consumption, pain scores, cutaneous sensory blockade, analgesic requirements, and adverse events for 46 h. RESULTS: The primary outcome of cumulative fentanyl consumption at 22 h showed no significant difference between the groups [group C: 11.9 (11.2-15.5) µg/kg (median (interquartile range)) and group PIB: 12.3 (11.6-15.3), p = 0.473]. Pain scores, demands for rescue analgesics, and spread of cutaneous sensory blockade were similar for the two groups. CONCLUSION: Programmed intermittent boluses of local anesthetic for continuous QLB did not produce better analgesia or wider sensory blockade compared with continuous basal infusion in patients undergoing laparoscopic colorectal surgery.

Continuous quadratus lumborum block and femoral nerve block for total hip arthroplasty: a randomized study.

BACKGROUND: Continuous femoral nerve block (FNB) has been effectively used after total hip arthroplasty (THA). Recently the anterior approach to quadratus lumborum block (QLB) has been shown to produce postoperative pain relief after THA. Continuous QLB would benefit from a catheter insertion site that is farther away from the surgical site compared with continuous FNB. In this randomized controlled study, we compared analgesic effects of the two techniques in patients undergoing THA. METHODS: Thirty patients undergoing THA were randomly allocated into two groups receiving continuous QLB and FNB. Under ultrasound guidance, QLB and FNB were conducted before general anesthesia using 0.25% levobupivacaine 30 ml and 0.5% levobupivacaine 15 ml, respectively, and a catheter was introduced. Postoperatively, all patients received continuous infusion of 0.125% levobupivacaine at 4 ml/h. Postoperative measurements included visual analog scale (VAS) pain scores at rest and on movement, postoperative analgesic demands, cutaneous sensory blockade and adverse events for 48 h. RESULTS: Six patients were excluded and 24 patients (13 and 11 patients in QLB group and FNB, respectively) were analyzed. VAS scores on movement at 6 h [median (IQR): 67 (41-80) and 38 (22-41) in QLB and FNB groups, respectively, p = 0.008] and 24 h [60 (40-80) and 39 (28-64) in QLB and FNB groups, respectively, p = 0.018] were lower with FNB than with QLB. QLB did not produce consistent cutaneous sensory blockade. CONCLUSIONS: Analgesic effects of continuous QLB were inferior to those of continuous FNB in patients undergoing THA under the current study condition.

Incidence and effects of unintentional intraneural injection during ultrasound-guided subgluteal sciatic nerve block.

BACKGROUND: The present study was conducted to determine the incidence of unintentional intraneural injection during ultrasound-guided subgluteal sciatic nerve block using a low-frequency transducer. We also observed the effects of intraneural injection using ropivacaine and mepivacaine. METHODS: Enrolled in the study were 325 patients undergoing arthroscopic knee surgery, who each received a subgluteal sciatic nerve block under ultrasound guidance using 1.5% mepivacaine with 1:400,000 epinephrine or 0.5% ropivacaine. A block needle was inserted in-plane with the ultrasound transducer (5-2 MHz curved array) and advanced slowly under real-time ultrasound guidance until it was positioned immediately adjacent to the nerve. Twenty milliliters of either anesthetic was then injected to produce a circumferential spread. An ultrasound video was recorded and used to examine whether the local anesthetic was injected intraneurally. Sensory and motor blockade was evaluated for 30 mins after completion of the block. Duration of the block and any neurologic complications were also examined. RESULTS: Intraneural injection was detected in 46 patients (16.3%; 95% confidence interval, 12.3%-20.3%). Onset of sensory and motor blockade was significantly faster in patients with intraneural injection than those without either mepivacaine or ropivacaine. Duration of sensory blockade was similar between patients with and without intraneural injection. No patient developed postoperative neurologic complications. CONCLUSIONS: Unintentional intraneural injection occurred at an incidence rate of 16.3% for the ultrasound-guided subgluteal approach to the sciatic nerve. Intraneural injection of mepivacaine or ropivacaine hastened the onset of blockade but did not affect block duration, and it did not result in clinical neural injury in our small sample of patients.

[Continuous peripheral nerve block with a catheter placed under ultrasound guidance for analgesia after major orthopedic surgery].

BACKGROUND: This prospective study was conducted to investigate the effects and complications of continuous peripheral nerve blocks after major orthopedic surgery using a catheter placed under ultrasound guidance. METHODS: We studied 182 adult patients who underwent one of three types of major orthopedic surgery and received peripheral nerve blocks with one or two perineural catheters: continuous femoral nerve block after reconstruction of the anterior cruciate ligament, n=93; continuous femoral with or without sciatic nerve block after total knee arthroplasty, n=39; and continuous brachial plexus block after arthroscopic surgery of the shoulder, n=50. All the patients received additional single peripheral nerve block and/or general anesthesia for surgery. A continuous injection of 0.2-0.25% ropivacaine was started immediately after surgery at a rate of 4-6 ml x hr(-1), with a 3 ml patient-controlled bolus available every 30 min, and lasted for at least 48hr. Pain was evaluated at rest and during movement, RESULTS: Despite large inter-individual variation, continuous peripheral nerve block produced satisfactory postoperative analgesia without any apparent major complications. CONCLUSIONS: Peripheral nerve block and catheter placement under ultrasound guidance may help manage postoperative analgesia after orthopedic surgery easily, reliably and safely.

Ultrasound-guided peripheral nerve blocks for anterior cruciate ligament reconstruction: effect of obturator nerve block during and after surgery.

PURPOSE: Three studies were conducted to determine whether and how the obturator nerve bears relevance to intra- and postoperative pain in patients undergoing anterior cruciate ligament (ACL) reconstruction using a hamstring autograft. METHODS: Patients undergoing arthroscopic ACL reconstruction using a hamstring autograft were enrolled in three studies. In the first study, we studied the analgesic effect of combined posterior lumbar plexus (PLP) and sciatic nerve blocks as well as combined femoral, lateral femoral cutaneous, and sciatic nerve blocks during and for 24 h after surgery. The second study was conducted to compare the analgesic effect of the combination of femoral, lateral femoral cutaneous, and sciatic nerve blocks with and without an obturator nerve block. Finally, we compared a postoperative continuous femoral nerve block and PLP block both during and for 48 h after surgery. RESULTS: In the first study, patients receiving the PLP block required significantly less fentanyl intraoperatively than those given the femoral nerve block. In the second, significantly less fentanyl was required during surgery for patients with the obturator nerve block than for those without. Finally, the continuous postoperative PLP block showed higher visual analog pain scores than those with the continuous femoral nerve block during movement at 48 h. CONCLUSION: The present results suggest the involvement of the obturator nerve in ACL reconstruction using a hamstring autograft. However, although obturator nerve blockade is crucial for intraoperative analgesia, a continuous obturator nerve block is not necessary beyond 24 h postoperatively.