Anterior Quadratus Lumborum Block at Lateral Supra-Arcuate Ligament vs Lateral Quadratus Lumborum Block for Postoperative Analgesia after Laparoscopic Colorectal Surgery: A Randomized Controlled Trial.

BACKGROUND: Quadratus lumborum block (QLB) has been found to be advantageous for laparoscopic colorectal surgery. This study hypothesized that preoperative anterior QLB at lateral supra-arcuate ligament (QLB-LSAL) would decrease postoperative opioid usage and offer improved analgesia within the context of multimodal analgesia compared with lateral QLB (LQLB) for laparoscopic colorectal surgery. STUDY DESIGN: In this randomized controlled trial, 82 American Society of Anesthesiologists physical status I to III class colorectal cancer patients undergoing laparoscopic radical resection were enrolled and randomly assigned to receive either LQLB or QLB-LSAL (0.375% ropivacaine 0.3 mL/kg bilaterally for each group). The primary outcomes were the total intravenous morphine equivalent consumption at 24 hours postoperatively. RESULTS: Intravenous morphine equivalent consumption at 24 hours postoperatively was significantly reduced in the QLB-LSAL group compared with that in the LQLB group with per-protocol analysis (29.2 ± 5.8 vs 40.5 ± 9.6 mg, p < 0.001) and intention-to-treat analysis (29.6 ± 6.1 vs 40.8 ± 9.5 mg, p < 0.001). Time to first patient-controlled analgesia request was notably longer in the QLB-LSAL group than that in the LQLB group (10.4 ± 3.9 vs 3.7 ± 1.5 hours, p < 0.001). CONCLUSIONS: Preoperative bilateral ultrasound-guided QLB-LSAL reduces morphine usage and extends the duration until the first patient-controlled analgesia demand within the framework of multimodal analgesia when compared with LQLB after laparoscopic colorectal surgery.

Circum-Psoas Block versus Supra-Inguinal Fascia Iliaca Block for Postoperative Analgesia in Patients Undergoing Total Hip Arthroplasty: A Randomized Clinical Trial.

Purpose: Total hip arthroplasty (THA) is often associated with moderate to severe pain. The present study compared the efficacy of circum-psoas block (CPB) with supra-inguinal fascia iliaca block (SIFIB) for postoperative analgesia in patients undergoing THA. Patients and Methods: In this randomized trial, sixty-four patients undergoing THA were allocated randomly to the CPB group or SIFIB group with 40 mL of 0.3% ropivacaine. The primary outcome was dynamic pain score at 6 h postoperatively. Secondary outcomes included dynamic pain scores at 12, 24 and 48 h; static pain scores; sensory and motor block; opioid consumption; time to first opioid request; length of hospital stay; patient satisfaction; and adverse events. Results: CPB patients showed significantly lower dynamic pain scores at 6 (3.11 ± 0.66 vs 4.47 ± 0.74, respectively; P = 0.000), 12 (2.52 ± 0.73 vs 3.53 ± 0.85, respectively; P = 0.000) and 24 h (2.30 ± 0.57 vs 2.87 ± 0.71, respectively; P = 0.001) after surgery, as well as lower static pain scores at 6 and 12h (P = 0.001 and P = 0.033 respectively) than SIFIB patients. Lower opioid consumption was observed in the CPB group at 24 and 48 h (P = 0.000, both) than in the SIFIB group. Patients in the CPB group reported improved quadriceps strength at 6 and 12 h (P = 0.000, both), as well as better muscle strength of hip flexion at 6, 12 and 24 h (P = 0.000, P = 0.000 and P = 0.025 respectively). Compared with SIFIB, CPB was associated with increased sensory block coverage at 6, 12 and 24 h (P = 0.000, P = 0.000, and P =0.022, respectively). Conclusion: CPB has a greater potential to alleviate postoperative pain and improve recovery in THA patients than SIFIB.

NETO2-GluK2 interaction contributes to postoperative pain hypersensitivity through inducing PKCγ activation and synaptic incorporation of AMPA receptor GluR1 subunits in rat dorsal horn.

Important roles in the initiation and maintenance of postoperative pain are played by the functional control of kainate (KA) and α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors in the rat dorsal horn (DH). However, the mechanisms underpinning the cross-talk between spinal KA and AMPA receptors in postoperative pain are poorly understood. We hypothesized that after the rat's plantar incision, the synaptic incorporation of AMPA receptor GluR1 subunits in the DH ipsilateral to the incision would increase due to the interaction between GluK2 and neuropilin tolloid-like 2 (NETO2). Our findings showed that incision stimuli caused severe pain responses, as measured by cumulative pain scores. GluK2-NETO2 but not GluK2-NETO1interaction was upregulated in ipsilateral dorsal horn neurons (DHNs) at 6 h post-incision. At 6 h post-incision, NETO2 small interfering ribonucleic acid (siRNA) intrathecal pretreatment increased mechanical withdrawal thresholds to von Freys and decreased ipsilateral paw cumulative pain scores. Further, PKCγactivation and synaptic abundance of GluK2 and GluR1 subunits in the ipsilateral DH were decreased by intrathecal pretreatment with NETO2 siRNA at 6 h post-incision. In conclusion, our findings imply that GluK2-NETO2 interaction could trigger PKCγactivation and the synaptic incorporation of AMPA receptor GluR1 subunits in rat DHs, which in turn led to the enhanced pain hypersensitivity after surgery. It sheds light on the interplay between KA and AMPA receptors in DHNs, which is thought to contribute to postoperative pain.

Role of Vagus Nerve Stimulation in the Treatment of Chronic Pain.

Vagus nerve stimulation (VNS) can modulate vagal activity and neuro-immune communication. Human and animal studies have provided growing evidence that VNS can produce analgesic effects in addition to alleviating refractory epilepsy and depression. The vagus nerve (VN) projects to many brain regions related to pain processing, which can be affected by VNS. In addition to neural regulation, the anti-inflammatory property of VNS may also contribute to its pain-inhibitory effects. To date, both invasive and noninvasive VNS devices have been developed, with noninvasive devices including transcutaneous stimulation of auricular VN or carotid VN that are undergoing many clinical trials for chronic pain treatment. This review aimed to provide an update on both preclinical and clinical studies of VNS in the management for chronic pain, including fibromyalgia, abdominal pain, and headaches. We further discuss potential underlying mechanisms for VNS to inhibit chronic pain.

Effects of Unilateral Intermediate Cervical Plexus Block on the Diaphragmatic Function in Patients Undergoing Unilateral Thyroidectomy: A Randomized Controlled Study.

Background and Purpose: Although unilateral intermediate cervical plexus block (ICPB) can be used for perioperative analgesia in neck surgery, its effect on diaphragm function remains controversial. This prospective study aimed to examine whether unilateral ICPB with different concentrations of ropivacaine resulted in the diaphragmatic dysfunction in unilateral thyroidectomy. Methods: A total of 54 patients scheduled to undergo unilateral thyroidectomy under general anesthesia were randomly allocated to receive either 10 mL of 0.3% (Group L) or 0.5% (Group H) ropivacaine for ICPB. General anesthesia was then administered for surgery. The diaphragm thickness and diaphragmatic excursion were measured at three different times: before the ICPB, at 40 min and 4 h after the block. The primary outcome was the incidence of diaphragmatic dysfunction of the block side at 40 min and 4 h after ICPB. Secondary outcomes included the maximum pain score within 24 h after the surgery, rescue analgesics within 24 h after the surgery, and time to first ambulation. Results: The incidence of diaphragmatic dysfunction on the block side of Group H was higher than that of Group L at 40 min after block (58% vs 29%, P = 0.01). However, the incidence of diaphragmatic dysfunction was comparable between Group H and Group L (65% vs 46%) at 4 h after block placement. Within 24 h after the operation, the maximum VAS pain score of Group H was significantly lower than Group L (P = 0.04), and fewer patients in Group H required rescue analgesics (P < 0.01). Conclusion: The ICPB with different concentrations of ropivacaine can induce the ipsilateral diaphragmatic dysfunction. The high concentration of ropivacaine results in higher incidence of diaphragmatic dysfunction at 40 min, but comparable incidence at 4 h after block compared with lower concentration of ropivacaine. Chinese Clinical Trial Registry: ChiCTR2000029348.

Evaluation of Sensory Loss and Postoperative Analgesia Obtained by Diaphragmatic Apposition Zone Block Under Direct Laparoscopic Visualization in Patients Undergoing Nephrectomy: A Descriptive Study.

Purpose: Local anesthetics can spread into the subendothoracic fascia compartment via the arcuate ligament and apposition zone of the diaphragm after the anterior quadratus lumborum blocks. Therefore, a new block may be achieved if local anesthetic is administered into the diaphragmatic apposition zone (DAZ) under direct laparoscopic visualization by surgeons. Therefore, we evaluated the sensory loss and postoperative analgesic efficacy of this new block in patients receiving laparoscopic nephrectomy. Methods: A total of 28 patients scheduled to receive elective laparoscopic nephrectomy under general anesthesia were enrolled in this study. The DAZ blocks were performed in patients under direct laparoscopic visualization with 20 mL of 0.5% ropivacaine before the dissected kidneys or renal tumors were taken out from the incision. All patients received the intravenous patient-controlled analgesia after surgery. The dermatomes of sensory loss and the muscle weakness of quadriceps femoris were assessed at 2 h post-surgery in the wards. The postoperative pain was scored. The opioid consumption in the first 24 h after surgery was recorded. Results: The average number of dermatomes of sensory block was 8.6 ± 1.2. The highest level of sensory loss was T6 (T5-T6) [median (interquartile range, IQR)], and the lowest level of sensory block was L1 (L1-L2). The postoperative pain scores at rest or on movement at 2 h, 6 h, 12 h, 24 h and 48 h were kept at the low levels (less than 4). The muscle strength of the quadriceps femoris evaluated was 5 (5-5) points [median (IQR)]. Total dose of intravenous morphine equivalent consumption in the first 24 h after surgery was 21.2 ± 4.1 mg. Conclusion: The DAZ block manifests a wide dermatomal coverage of sensory loss and is associated with the low levels of postoperative pain intensity and opioid use. It provides a new postoperative analgesia option for patients undergoing laparoscopic nephrectomy.

Understanding fascial anatomy and interfascial communication: implications in regional anesthesia.

With the extensive application of ultrasound in regional anesthesia, there has been rapid development of interfascial plane block techniques recently. Compared with neuraxial anesthesia or nerve plexus blocks, the interfascial plane blocks have many advantages, such as technical simplicity, fewer complications and comparable or better analgesia. The concept of fascial interconnectivity is fundamental in understanding the effects and complications of interfascial plane blocks. Many fascial planes are continuous and communicate with each other without a clear anatomical boundary. The prevertebral fascia of the neck, endothoracic fascia of the chest, transversalis fascia of the abdomen, and the fascia iliaca of the pelvic cavity form a natural fascial continuation. This anatomical feature suggests that the space beneath the cervical prevertebral fascia, the thoracic paravertebral space, the space between transversalis fascia and psoas muscles (psoas major and quadratus lumborum), and the fascia iliaca compartment are a confluent potential cavity. Additionally, the permeability of the fascia at different anatomical locations to local anesthetics is different, which can also influence the block effect and the incidence of complications. This article summarizes the anatomical characteristics and communication relationships of the major fascia which are related to regional anesthesia, and their relationships with block effects and complications.

Evaluation of Sensory Loss Obtained by Circum-Psoas Blocks in Patients Undergoing Total Hip Replacement: A Descriptive Pilot Study.

Purpose: The transversalis fascia (TF) encases the quadratus lumborum and psoas major (PM) muscles, respectively, after they split caudalward approximately at the level of the iliac crest. The branches of the lumbar plexus variably exit medially and laterally from the TF-encased PM muscle. We hypothesized that the local anesthetic (LA) injections around the anterolateral edge of PM at the supra-iliac level and into the retro-psoas compartment at the L5/S1 level, which termed as the circum-psoas blocks, could block the lumbar plexus branches. Therefore, here we evaluated the sensory loss caused by the circum-psoas blocks. Methods: A total of 26 patients scheduled for total hip replacement were recruited for the study. After anesthesia induction, the ultrasound-guided circum-psoas blocks were performed in the lateral position with the affected side upward, in which the 0.3% ropivacaine was injected posterior to the TF and around the anterolateral edge of PM muscle at the supra-iliac level (25 mL), and into the retro-psoas compartment at the L5/S1 level (20 mL). The sensory block dermatomes and the muscle strength of quadriceps femoris were evaluated at 2 h or 6 h after surgery, respectively. The postoperative pain scores and opioid consumption were recorded. Results: The median (interquartile range) highest and lowest dermatomes of sensory block were T10 (T9-T10) and S2 (S2-S2), respectively. The muscle strength of the quadriceps femoris evaluated at 6 h post-surgery was 4 (4-5) points. Total postoperative equivalent milligrams of oral morphine consumption in the first 24 h were 11.3 ± 3.6 mg. Conclusion: The circum-psoas blocks may be a promising approach for postoperative analgesia of hip surgery, since they provide a dermatomal coverage of sensory block from T8-11 to S1-3. Clinical Trial Registration: Chinese Clinical Trial Registry, clinical trial number ChiCTR2100051247.

Supra-Arcuate Ligament Blocks: Anatomy, Mechanisms, and Techniques.

Quadratus lumborum block (QLB) is clinically used for postoperative analgesia of abdominal or hip surgery, which can reduce the dose of general anesthetic, inhibit postoperative pain, and promote postoperative rehabilitation. However, accumulated studies have shown several drawbacks of QLB, such as only a small portion of local anesthetic spread into the thoracic paravertebral space, relatively longer onset time, and easily-influenced block effect by the integrity of lumbar fascia, etc. Therefore, on the basis of traditional anterior QLB, our group proposed the techniques of a supra-arcuate ligament block, which include a paramedian short-axis scanning approach, paramedian long-axis scanning approach, infra-lateral arcuate ligament QLB with the apposition zone between diaphragm and quadratus lumborum as drug diffusion target and supra-arcuate ligament block under direct laparoscopic visualization. Recent studies have demonstrated that the supra-arcuate ligament blocks have the advantages of clear anatomy, are easy to perform, and have rapid onset, which avoid some drawbacks of the conventional QLB techniques. This article reviews the anatomical basis, sonoanatomy, technical points, and clinical considerations of supra-arcuate ligament blocks.