Anterior quadratus lumborum catheters for elective cesarean section: A double-blind, randomized, placebo-controlled trial.

BACKGROUND: Optimizing pain management following cesarean section is crucial for the well-being of both mother and infant. Various types of quadratus lumborum blocks have exhibited reduced opioid consumption and pain scores after cesarean section. However, duration of block effect is relatively short. The aim of this study was to investigate the analgesic efficacy of the anterior quadratus lumborum catheters for cesarean section. METHODS: All 32 enrolled participants were allocated to postoperative bilateral ultrasound-guided anterior quadratus lumborum catheter placement with injection of 60 mL ropivacaine 0.375% after cesarean section. Randomization at 2 h resulted in either 60 mL ropivacaine 0.2% or 60 mL isotonic saline injected through the catheters, with subsequent 22-h infusion of either ropivacaine 0.2% or isotonic saline with an infusion rate of 4 mL h-1 per catheter. Participants in the active group received a total of 697 mg ropivacaine during the first 24 h. All participants received the standard postoperative multimodal pain regimen, and a final bilateral injection at 24-h post-catheter placement of 60 mL ropivacaine 0.375% in total. The primary outcome was time to first opioid administration. Secondary outcomes were pain scores, time to first ambulation, nausea and vomiting, accumulated opioid consumption, and catheter displacement rates. RESULTS: No significant intergroup differences were observed following the randomized intervention. Median time to first opioid (IQR) was (active vs. placebo) 414 (283, 597) vs. 428 (245, 552) minutes, with a median difference (CI) of -14 (-184 to 262) min, p = .32. CONCLUSION: Bilateral anterior quadratus lumborum catheters with continuous infusion did not prolong time to first opioid after elective cesarean section.

The intertransverse process block single- or multiple-injection? A study protocol.

BACKGROUND AND AIMS: Intertransverse process (ITP) blocks are applied on the posterior side of the thoracic paravertebral space. The modality is described as being a paravertebral block by proxy, possibly providing a similar analgesic effect as the thoracic paravertebral block. However, systematic evidence on anaesthetised dermatomes and the extent of cutaneous sensory loss following ITP blocks is sparse. This study aims to test the single- versus the multiple-injection ITP block. The primary outcome is the number of anaesthetised thoracic dermatomes for each block type. METHODS: Twelve healthy male volunteers will participate in this randomised, procedure-related, double-blinded, non-inferiority crossover trial after informed consent. Blinded participants will receive either a unilateral single-injection ITP block with 21 mL ropivacaine 7.5 mg/mL including two sham blocks or a unilateral multiple-injection ITP block with 3 × 7 mL ropivacaine 7.5 mg/mL on study Day 1, and the other modality on study Day 2. Block applicants will be blinded from outcome assessment and vice versa. Following block application sensory test by mechanical pinprick and temperature discrimination will be performed. Anterior truncal thermography will be measured three times after block application to compare skin temperature in the mid-clavicular line between the blocked and the contralateral non-blocked hemithorax. In addition, blood pressure changes are measured three times non-invasively. DISCUSSION: The current study will provide substantial knowledge regarding the cutaneous sensory loss of the ITP block. Furthermore, the study might provide insight regarding the possible clinical usage of thermography as a reliable instrument for measuring nerve block efficacy.

Ultrasound-guided multiple-injection costotransverse block for mastectomy and primary reconstructive surgery. A study protocol.

BACKGROUND: Post-operative pain amelioration following breast cancer surgery is inconsistent. The novel multiple-injection costotransverse block (MICB) mimics the thoracic paravertebral block by possible anaesthetising the ventral rami of the thoracic spinal nerves and the sympathetic trunk. Proof of concept has been determined in a cadaveric study and needs further clinical testing. METHODS: This double-blinded, randomised and placebo-controlled study investigates the efficacy of the ultrasound-guided MICB versus placebo in 36 patients undergoing unilateral mastectomy and primary subpectoral reconstruction surgery. Oral pre-operative medicine is standardised for all patients. Active group is pre-operatively administered MICB with three injections of each 10 ml of ropivacaine (5 mg/ml). The placebo group is pre-operatively administered three injections of each 10 ml of saline (0.9%). Standard general anaesthesia is induced and 30 min before emergence 0.2 µg/kg total body weight sufentanil IV, 1 g of paracetamol IV and 4 mg of ondansetron IV (post-operative nausea and vomiting, PONV, prophylaxis) will be administered. All patients are provided with a patient-controlled analgesia pump with morphine. The primary aim is total morphine consumption in the first 24 post-operative hours. Secondary aims are pain intensity, duration of the block, patient satisfaction, side effects, time to ambulation, time to discharge, and quality of recovery. DISCUSSION: Recruitment began in November 2019 and is expected to finish ultimo 2021. Results are expected to be published in an international peer-reviewed medical journal. The results will hopefully provide a substantial contribution to the knowledge of these new 'intertransverse process blocks' providing regional anaesthesia of the thoracic wall.

Ultrasound-guided transmuscular quadratus lumborum catheters for elective caesarean section: A protocol for a single-centre, double-blind randomised trial.

BACKGROUND: Management of moderate-to-severe post-operative pain after elective caesarean section (ECS) is internationally primarily based on either epidural catheters or opioids. However, both techniques are associated with some undesirable adverse events. Bilateral transmuscular quadratus lumborum (TQL) block has proven to reduce opioid consumption significantly in the first 24 post-operative hours following ECS and prolong time to first opioid (TFO) (Hansen CKD, Steingrimsdottir M, Laier GE, et al. Reg Anesth Pain Med. 2019; 10.1136/rapm-2019-100540). We present a randomised controlled trial aiming to investigate whether continuous analgesia via bilateral TQL catheters can prolong TFO after ECS. METHODS: This study is a double-blind, randomised, placebo-controlled trial. Patients should be 18 years or older and scheduled for ECS under spinal anaesthesia to be included. Main exclusion criteria are inability to cooperate, excessive daily intake of opioids and difficult ultrasound visualisation of muscular and fascial structures. Participants are randomised to receive ultrasound-guided injection of either 30 mL ropivacaine 0.2% bilaterally and an elastomeric pump containing 0.2% ropivacaine, or 30 mL saline bilaterally and an elastomeric pump containing saline, 2 hours after catheter placement. The primary endpoint is TFO. Secondary outcomes include pain intensity on a numeric rating scale (NRS), accumulated morphine consumption during 24 hours, displacement frequency of catheters and morphine-related adverse events. RECRUITMENT PERIOD: Four patients were included from September 2018 to November 2018. Inclusion was resumed in June 2019 and will continue until 24 patients with useful data have been included in the trial. Expected inclusion period is 10-14 months. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03663478. EudraCT: 2017-003625-15.

Transmuscular quadratus lumborum block for percutaneous nephrolithotomy: Study protocol for a dose-finding trial.

BACKGROUND: The objective of this trial is to optimize the transmuscular quadratus lumborum (TQL) block, by investigating the minimal effective volume (MEV90 ) of ropivacaine 0.75% for single-shot TQL block in percutaneous nephrolithotomy (PNL) patients. METHODS: This double-blind, randomized and controlled dose-finding trial is based on a biased coin up-and-down sequential design, where the volume of local anaesthetic administered to each patient depends on the response from the previous one. Investigating the TQL block, the first patient recruited receives 20 ml ropivacaine 0.75% preoperatively. In case of block failure, the next patient will receive the same volume with an increment of 2 ml. Given a successful block for the first patient, the next patient will be randomized to either a lower volume (previous volume with a reduction of 2 ml), or the same volume as the previous patient. The respective probabilities being b = 0.11 for a reduced volume and 1-b = 0.89 for the same volume. Block success is defined as patient reported pain score numeric rated scale (NRS) ≤3 (0-10/10) 30 minutes after arrival in the post anaesthesia care unit (PACU). The NRS pain score is our primary and only outcome for block success. A minimum of 25 eligible patients are needed to achieve precise estimation of MEV90 with narrow 95% confidence intervals derived by bootstrapping. DISCUSSION: Recruiting will begin June 2020 and is expected to finish November 2020. Data analysis will be performed at interims during and after the study. Results will be published in an international peer-reviewed medical journal.

An iliopsoas plane block does not cause motor blockade-A blinded randomized volunteer trial.

BACKGROUND: A femoral nerve block relieves pain after total hip arthroplasty, but its use is controversial due to motor paralysis accompanied by an increased risk of fall. Assumedly, the iliopsoas plane block (IPB) targets the hip articular branches of the femoral nerve without motor blockade. However, this has only been indicated in a cadaver study. Therefore, we designed this volunteer study. METHODS: Twenty healthy volunteers were randomly allocated to blinded paired active vs. sham IPB (5 mL lidocaine 18 mg/mL with epinephrine vs saline). The primary outcome was reduction of maximal force of knee extension after IPB compared to baseline. Secondary outcomes included reduction of maximal force of hip adduction, and the pattern of injectate spread assessed with magnetic resonance imaging. RESULTS: Mean (confidence interval) change of maximal force of knee extension from baseline to after IPB was -9.7 N (-22, 3.0) (P = .12) (n = 14). The injectate was consistently observed in an anatomically well-defined closed fascial compartment between the intra- and extra-pelvic components of the iliopsoas muscle anterior to the hip joint. CONCLUSION: We observed no significant reduction of maximal force of knee extension after an IPB. The injectate was contained in a fascial compartment previously shown to contain all sensory branches from the femoral nerve to the hip joint. The clinical consequence of selective anesthesia of all sensory femoral nerve branches from the hip could be a reduced risk of fall compared to a traditional femoral nerve block. Registration of Trial: The trial was prospectively registered in EudraCT (Reference: 2018-000089-12, https://www.clinicaltrialsregister.eu/ctr-search/search?query=2018-000089-12).

Transmuscular quadratus lumborum block for percutaneous nephrolithotomy reduces opioid consumption and speeds ambulation and discharge from hospital: a single centre randomised controlled trial.

BACKGROUND: Percutaneous nephrolithotomy (PNL) is associated with severe postoperative pain. The current study aimed to investigate the analgesic efficacy of transmuscular quadratus lumborum (TQL) block for patients undergoing PNL surgery. METHODS: Sixty patients were enrolled in this single centre study. The multimodal analgesic regime consisted of oral paracetamol 1 g and i.v. dexamethasone 4 mg before surgery and i.v. sufentanil 0.25 µg kg-1 30 min before emergence. After operation, patients received paracetamol 1 g regularly at 6 h intervals. Subjects were allocated to receive a preoperative TQL block with either ropivacaine 0.75%, 30 ml (intervention) or saline 30 ml (control). Primary outcome was oral morphine equivalent (OME) consumption 0-6 h after surgery. Secondary outcomes were OME consumption up to 24 h, pain scores, time to first opioid, time to first ambulation, and hospital length of stay. Results were reported as mean (standard deviation) or median (inter-quartile range). RESULTS: Morphine consumption was lower in the intervention group at 6 h after surgery (7.2 [8.7] vs 90.6 [69.9] mg OME, P<0.001) and at 24 h (54.0 [36.7] vs 126.2 [85.5] mg OME, P<0.001). Time to first opioid use was prolonged in the intervention group (678 [285-1020] vs 36 [19-55] min, P<0.0001). Both the time to ambulation (302 [238-475] vs 595 [345-925] min, P<0.004) and length of stay (2.0 [0.8] vs 3.0 [1.2] days, P≤0.001) were shorter in the intervention group. CONCLUSIONS: This is the first blinded, RCT that confirms that unilateral TQL block reduces postoperative opioid consumption and hospital length of stay. Further study is required for confirmation and dose optimisation. CLINICAL TRIAL REGISTRATION: NCT02818140.

Are single-injection erector spinae plane block and multiple-injection costotransverse block equivalent to thoracic paravertebral block?

BACKGROUND: Thoracic paravertebral block (TPVB) is considered the gold standard for hemithoracic regional anaesthesia. Erector spinae plane block (ESPB) is a new posterior thoracic wall block. Multiple-injection costotransverse block (MICB) mimics TPVB but with injection points within the thoracic intertransverse tissue complex and posterior to the superior costotransverse ligament. We aimed to compare the spread of injectate into the thoracic paravertebral space (TPVS) resulting from single-injection ESPB and MICB, respectively, with TPVB. METHODS: Ten soft-embalmed cadavers were utilised. In five cadavers, the right hemithorax was randomly allocated either to ultrasound-guided single-injection ESPB or single-injection TPVB; vice versa on the other side. In another five cadavers, the right hemithorax was randomly allocated either to ultrasound-guided MICB or multiple-injection TPVB. About 20 mL of dye was injected in each hemithorax with all techniques. RESULTS: With TPVB, the dye was consistently present in the TPVS with concomitant epidural spread in the majority of cases. The injectate spread into the TPVS with ESPB (60%) and MICB (100%). MICB consistently stained the ventral rami (T1-7), communicating rami and thoracic sympathetic trunk without epidural spread. Dissection after MICB revealed dye spread into the TPVS via the costotransverse foramina and along the dorsal branches of the posterior intercostal veins. CONCLUSIONS: Consistent spread of dye into the TPVS colouring the ventral rami, the communicating rami, and the sympathetic trunk was observed with MICB; in this respect equivalent to TPVB. ESPB exhibited only partial success and was not equivalent to TPVB. No epidural spread was found with neither MICB nor ESPB.

Cutaneous anaesthesia of hip surgery incisions with iliohypogastric and subcostal nerve blockade: A randomised trial.

BACKGROUND: Cutaneous nerve blockade may improve analgesia after hip surgery. Anaesthesia after the lateral femoral cutaneous (LFC) nerve block is too distal for complete coverage of most hip surgery incisions, which requires additional anaesthesia of the adjacent, proximal area. The transversalis fascia plane (TFP) block potentially anaesthetises the iliohypogastric and subcostal nerves. The primary aim of the present study was to investigate, if the TFP block provides cutaneous anaesthesia adjacent to the LFC nerve block. METHODS: Active vs placebo TFP blocks were compared in a paired randomised controlled trial (RCT) in 20 volunteers, who all had bilateral LFC nerve blocks. The day preceding the RCT, the area anaesthetised by a novel selective ultrasound guided subcostal nerve block was identified bilaterally in order to assess the contribution of the subcostal nerve to the area anaesthesia by the TFP block. RESULTS: Anaesthesia of the lateral hip region after TFP block was 80%. The cutaneous anaesthesia after active TFP block was in continuity with the LFC nerve block in 65%. Combined TFP and LFC nerve blockade significantly increased the coverage of hip surgery incisions compared to LFC nerve block alone. The success rate of blocking the subcostal nerve was 50% with the TFP block. CONCLUSION: The TFP block anaesthetises the skin proximal to the LFC nerve block by anaesthetising the iliohypogastric and subcostal nerves. TFP block as a supplement to LFC nerve block improves the coverage of the proximal surgical incisions used for hip surgery.

The Pathway of Injectate Spread With the Transmuscular Quadratus Lumborum Block: A Cadaver Study.

BACKGROUND: The spread of injectate resulting from a transmuscular quadratus lumborum (TQL) block and a transverse oblique paramedian (TOP) TQL block has never been examined. The aim of this cadaveric study was to investigate by which pathway the injectate spreads cephalad into the thoracic paravertebral space and which nerves were dyed by the injectate cephalad and caudad to the diaphragm when performing a TQL and a TOP TQL block. We also aimed to investigate whether the thoracic and lumbar sympathetic trunks as well as the lumbar plexus were covered by the injectate. METHODS: Ultrasound-guided bilateral TQL and TOP TQL injections were administered in 8 cadavers. A total of 16 injections were performed. With the TQL injection, the curvilinear transducer was oriented in the transverse plane above the iliac crest at the posterior axillary line to identify the Shamrock sign. With the TOP TQL injection, the same transducer was placed with a TOP orientation 3 cm lateral to the L2 spinous process to identify the L2 transverse process and the adjoining quadratus lumborum muscle. For both techniques, the needle was advanced in-plane to the transducer, with the end point in the interfascial plane between the quadratus lumborum and psoas major muscles. Thirty milliliters of dye solution was injected bilaterally for each technique. The spread of the dye was evaluated by subsequent dissection. RESULTS: In all successful injections, the dye was seen to spread into the thoracic paravertebral space and the intercostal spaces to surround the somatic nerves and the thoracic sympathetic trunk. The main pathway of spread of injectate was posterior to the medial and lateral arcuate ligaments. Caudad to the diaphragm, the injected dye surrounded the subcostal, iliohypogastric, and ilioinguinal nerves in all cases, whereas the genitofemoral and lateral femoral cutaneous nerves were dyed in a varying degree. No dye was seen to surround the lumbar plexus, femoral nerve, or lumbar sympathetic trunk. The pattern of spread was similar with the TQL and TOP TQL injections. CONCLUSIONS: The spread of injectate with the TQL and TOP TQL approaches is cephalad from the lumbar point of administration between the quadratus lumborum and psoas major muscles, predominantly via a pathway posterior to the arcuate ligaments and into the thoracic paravertebral space to reach the somatic nerves and the thoracic sympathetic trunk in the intercostal and paravertebral spaces. The lumbar plexus and lumbar sympathetic trunk are not affected.

Abdominal wall blocks in adults.

PURPOSE OF REVIEW: Abdominal wall blocks in adults have evolved much during the last decade; that is, particularly with the introduction of ultrasound-guided (USG) blocks. This review highlights recent advances of block techniques within this field and proposes directions for future research. RECENT FINDINGS: Ultrasound guidance is now considered the golden standard for abdominal wall blocks in adults, even though some landmark-based blocks are still being investigated. The efficiency of USG transversus abdominis plane blocks in relation to many surgical procedures involving the abdominal wall is the most common nerve block effect measurement investigated in goal-directed research. The advent of the various quadratus lumborum block techniques with a long-lasting analgesic effect have opened up a new area of research, and the use of liposomal bupivacaine for transversus abdominis plane blocks have been introduced with success. Future research should also investigate the effect of specific abdominal wall blocks on neuroendocrine and inflammatory stress response after surgery. SUMMARY: USG abdominal wall blocks in adults are commonplace techniques today. Most abdominal wall blocks are assigned evidence grade A or B according to the US Agency for Healthcare Policy and Research guidelines.

Combined saphenous and sciatic catheters for analgesia after major ankle surgery: a double-blinded randomized controlled trial.

PURPOSE: Continuous sciatic nerve block is used for pain management following major ankle surgery. Pain from the saphenous nerve territory often persists. We conducted a double-blinded randomized placebo-controlled trial to evaluate the effect of a supplementary saphenous catheter in the proximal thigh combined with a popliteal sciatic catheter and single-shot saphenous nerve block after major ankle surgery. METHODS: Fifty patients received both sciatic and saphenous continuous catheters inserted along the short axis of the nerves with ultrasound-guidance. All patients had an initial sciatic nerve block followed by a continuous sciatic catheter infusion and an initial saphenous nerve block with ropivacaine. Participants were then randomized to infusion of either ropivacaine or isotonic saline in the saphenous catheter for 48 hr postoperatively. The primary outcome was total intravenous morphine consumption during the first 48 hr postoperatively. Secondary outcomes were clinical analgesia, saphenous analgesia, territory of worst pain, and patient satisfaction. RESULTS: Forty-four patients were included in the analysis. The mean (SD) 48-hr morphine consumption was 24.7 (21.6) mg in the intervention group and 27.8 (20.1) mg in the placebo group (P = 0.63). The mean difference in 48-hr morphine consumption was 3.0 mg (95% confidence interval, -9.7 to 15.7). There were no differences regarding the secondary outcomes. CONCLUSION: A saphenous catheter with a low-dose continuous infusion of ropivacaine, as an adjunct to a sciatic catheter, had no effect on the postoperative analgesia after major ankle surgery when both catheters were inserted along the short axis of the nerves. This trial was registered at ClinicalTrials.gov (NCT01445210).

The Shamrock lumbar plexus block: A dose-finding study.

BACKGROUND: The Shamrock technique is a new method for ultrasound-guided lumbar plexus blockade. Data on the optimal local anaesthetic dose are not available. OBJECTIVE: The objective of this study is to estimate the effective dose of ropivacaine 0.5% for a Shamrock lumbar plexus block. DESIGN: A prospective dose-finding study using Dixon's up-and-down sequential method. SETTING: University Hospital Orthopaedic Anaesthesia Unit. INTERVENTION: Shamrock lumbar plexus block performance and block assessment were scheduled preoperatively. Ropivacaine 0.5% was titrated with the Dixon and Massey up-and-down method using a stepwise change of 5 ml in each consecutive patient. Combined blocks of the femoral, the lateral femoral cutaneous and the obturator nerve were prerequisite for a successful lumbar plexus block. PATIENTS: Thirty patients scheduled for lower limb orthopaedic surgery completed the study. MAIN OUTCOME MEASURES: The minimum effective anaesthetic volume of ropivacaine 0.5% (ED50) to achieve a successful Shamrock lumbar plexus block in 50% of the patients. Further analysis of the data was performed with a logistic regression model to calculate ED95 and to estimate the effective doses for a sensory lumbar plexus block not requiring a motor block of the femoral nerve. RESULTS: The Dixon and Massay estimate of the ED50 was 20.4 [95% confidence interval (95% CI) 13.9 to 30.0] ml ropivacaine 0.5%. The logistic regression estimate of the ED95 was 36.0 (95% CI 19.7 to 52.2) ml ropivacaine 0.5%. For a sensory lumbar plexus block, the ED50 was 17.1 (95% CI 12.3 to 21.9) ml and the ED95 was 25.8 (95% CI 18.6 to 33.1) ml. CONCLUSION: A volume of 20.4 ml ropivacaine 0.5% provided a successful Shamrock lumbar plexus block in 50% of the patients. A volume of 36.0 ml would be successful in 95% of the patients. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT01956617.

Perioperative transfusion threshold and ambulation after hip revision surgery--a randomized trial.

BACKGROUND: Transfusion with red blood cells (RBC) may be needed during hip revision surgery but the appropriate haemoglobin concentration (Hb) threshold for transfusion has not been well established. We hypothesized that a higher transfusion threshold would improve ambulation after hip revision surgery. METHODS: The trial was registered at Clinicaltrials.gov ( NCT00906295). Sixty-six patients aged 18 years or older undergoing hip revision surgery were randomized to receive RBC at a Hb threshold of either 7.3 g/dL (restrictive group) or 8.9 g/dL (liberal group). Postoperative ambulation was assessed using Timed Up and Go-test (TUG) and ability to walk was also assessed daily by a physiotherapist blinded to the allocation. RESULTS: Fifty-three patients were able to perform the TUG and included in the analysis. The TUG could be completed in a median of 36 sec vs. 30 sec in the restrictive group and the liberal group, respectively (P = 0.02). The mean difference in TUG was 14.5 sec (95% CI 2.8-26.2 sec). No difference was found in the day patients could perform TUG or walk 10 meters. The Hb at the day of testing was 10.2 g/dL in the restrictive group and 9.9 g/dL in the liberal group. Only 26 patients received RBC. CONCLUSIONS: A Hb transfusion threshold of 8.9 g/dL was associated with a statistically significantly faster TUG after hip revision surgery compared to a threshold of 7.3 g/dL but the clinical importance is questionable and the groups did not differ in Hb at the time of testing.

Insignificant influence of the intertransverse process block for major breast cancer surgery: a randomized, blinded, placebo-controlled, clinical trial.

INTRODUCTION: The intertransverse process (ITP) block mimics the thoracic paravertebral block and allegedly ameliorates hemithoracic postoperative pain. However, concerning major reconstructive breast cancer surgery the modality has never been tested against placebo in a randomized clinical trial. We aimed to assess the efficacy of the multiple-injection ITP block and hypothesized that the blockade would reduce postoperative opioid consumption. METHODS: We screened 58 patients with breast cancer scheduled for unilateral subpectoral implant-based primary breast reconstruction, involving mastectomy with complete fascial dissection of the major pectoral muscle. A randomization procedure allowed for the allocation of 36 patients to receive either unilateral multiple-injection active ITP block (0.5% ropivacaine 3×10 mL) or placebo ITP block (isotonic saline 3×10 mL) at T2, T4, T6 in a prospective, blinded, clinical trial. The primary outcome was total opioid consumption within the first 24 postoperative hours. Secondary outcomes included opioid consumption at 4-hour intervals, postoperative pain, patient satisfaction with block application, time to first opioid, ambulation and discharge, opioid-related side effects, and quality of recovery. RESULTS: Opioid consumption within the first 24 postoperative hours showed no significant reduction when comparing the active and placebo group median (IQR): 75.0 mg (45-135) vs 62.5 mg (30-115), p=0.5, respectively. We did not find any consequential clinically relevant results of the secondary outcomes. CONCLUSIONS: Following major reconstructive breast cancer surgery, a preoperative multiple-injection ITP block neither reduces 24-hour opioid consumption postoperatively nor promotes substantial clinical positive outcomes. TRIAL REGISTRATION NUMBER: EudraCT2019-001016-35.

No quadriceps muscle weakness following anterior quadratus lumborum block compared with placebo: a randomized, non-inferiority, blinded, volunteer trial.

BACKGROUND AND AIMS: Anterior quadratus lumborum block is a truncal block, applied in close proximity to the lumbar plexus, potentially causing lower limb weakness. This trial aimed to evaluate whether a unilateral anterior quadratus lumborum block caused quadriceps muscle weakness compared with placebo. METHODS: In this randomized, non-inferiority, triple-blind trial, 20 healthy volunteers received an active unilateral anterior quadratus lumborum block with 30 mL ropivacaine 0.75% and a placebo block on the contralateral side. Primary outcome was change in maximal quadriceps muscle strength from baseline to 60 min postblock compared with placebo. Secondary outcomes were change in single-leg 6 m timed hop test, change in Timed-Up and Go test, change in mean arterial pressure from baseline to 30 min postblock and dermatomal affection. RESULTS: There was no statistically significant difference in changes in maximal quadriceps muscle strength between active and placebo block; 15.88 N (95% CI -12.19 to +43.94), pnon-inf=0.003, indicating non-inferiority. Timed-Up and Go test was performed significantly faster 60 min postblock; -0.23 s (95% CI -0.38 to -0.08, p=0.005). Mean change in mean arterial pressure from baseline to 30 min postblock was 4.25 mm Hg (95% CI 0.24 to 8.26, p=0.04). Dermatome testing revealed an affection primarily of the lower abdomen (Th10-L1) with the active block. CONCLUSION: In this randomized controlled trial including healthy volunteers a unilateral anterior quadratus lumborum block does not cause statistical or clinical significant motor block of the quadriceps muscle compared with placebo. When administered correctly, the block can be used for procedures where early postoperative mobilization is essential. TRIAL REGISTRATION NUMBER: NCT05023343.

Anterior quadratus lumborum block does not reduce postoperative opioid consumption following laparoscopic hemicolectomy: a randomized, double-blind, controlled trial in an ERAS setting.

BACKGROUND AND AIMS: An opioid-sparing postoperative analgesic regimen following laparoscopic hemicolectomy is optimal to promote minimal postoperative pain, early mobilization, and improved quality of recovery. Various regional anesthesia techniques have been tested to improve postoperative pain management after laparoscopic hemicolectomy. In this study, we aimed to assess the effect of administering a preoperative bilateral ultrasound-guided anterior quadratus lumborum nerve block on postoperative opioid consumption after laparoscopic colon cancer surgery. METHODS: In this randomized, controlled, double-blinded trial, 69 patients undergoing laparoscopic hemicolectomy due to colon cancer were randomized to receive an anterior quadratus lumborum block with ropivacaine 0.375% 30 mL on each side or isotonic saline (placebo). The primary outcome measure was total opioid consumption during the first 24 hours postsurgery. The secondary outcome measures were pain scores, accumulated opioid consumption in 6-hour intervals, nausea and vomiting, ability of postoperative ambulation, time to first opioid, orthostatic hypotension or intolerance, postoperative Quality of Recovery-15 scores, surgical complications, length of hospital stay, and adverse events. RESULTS: The total opioid consumption in the first 24 hours postsurgery was not significantly reduced in the ropivacaine group compared with the saline group (mean 129 mg (SD 88.4) vs mean 127.2 mg (SD 89.9), p=0.93). In addition, no secondary outcome measures showed any statistically significant intergroup differences. CONCLUSION: The administration of a preoperative bilateral anterior quadratus lumborum nerve block as part of a multimodal analgesic regimen for laparoscopic hemicolectomy did not significantly reduce opioid consumption 24 hours postsurgery. Trial registration number NCT03570541.

Efficacy of the intertransverse process block: single or multiple injection? A randomized, non-inferiority, blinded, cross-over trial in healthy volunteers.

INTRODUCTION: The intertransverse process block is increasingly used to ameliorate postoperative pain following a plethora of surgical procedures involving the thoracic wall. Nevertheless, the optimal approach and cutaneous extent of the sensory block are currently unknown. We aimed to further describe the intertransverse process block, single injection versus multiple injection, and we hypothesized that the single-injection intertransverse process block is a non-inferior technique. METHODS: Twelve healthy male volunteers were cross-over randomized to receive either single-injection intertransverse process block with 21 mL ropivacaine 7.5 mg/mL, including two sham injections, at the thoracic level T4/T5 or multiple-injection intertransverse process block with three injections of 7 mL ropivacaine 7.5 mg/mL at the thoracic levels T2/T3, T4/T5 and T6/T7 at the first visit. At the second visit, the other technique was applied on the contralateral hemithorax. A non-inferiority margin of 1.5 anesthetized thoracic dermatomes was chosen. RESULTS: The mean difference (95% CI) in the number of anesthetized thoracic dermatomes was 0.82 (-0.41 to 2.05) pnon-inf<0.01 indicating non-inferiority favoring the single-injection technique.Both techniques anesthetized the ipsilateral thoracic wall and demonstrated contralateral cutaneous involvement to a variable extent. The multiple-injection intertransverse process block anesthetized a significantly larger cutaneous area on the posterior hemithorax and decreased mean arterial pressure at 30 and 60 min postblock application. Thoracic thermography showed no intermodality temperature differences yet compared with baseline temperatures both techniques showed significant differences. CONCLUSIONS: Single-injection intertransverse process block is non-inferior to multiple injection in terms of anesthetized thoracic dermatomes. Both techniques generally anesthetize the hemithoracic wall to a variable extent. EU CLINICAL TRIALS REGISTER: 2022-501312-34-01.

Effect of anterior quadratus lumborum block with ropivacaine on the immune response after laparoscopic surgery in colon cancer: a substudy of a randomized clinical trial.

BACKGROUND: Surgery induces a temporal change in the immune system, which might be modified by regional anesthesia. Applying a bilateral preoperative anterior quadratus lumborum block has proven to be a safe and effective technique in pain management after abdominal and retroperitoneal surgery, but the effect on the immune response is not thoroughly investigated. METHODS: This study is a substudy of a randomized, controlled, double-blinded trial of patients undergoing laparoscopic hemicolectomy due to colon cancer. Twenty-two patients were randomized to undergo either a bilateral anterior quadratus lumborum nerve block with a total of 60 mL ropivacaine 0.375% or placebo with corresponding isotonic saline injections. The main objective of this exploratory substudy was to investigate the systemic immune response in the first postoperative day by examining changes in blood transcript levels (n=750) and stimulated secretion of cytokines (n=17) on ex vivo activation with microbial ligands and anti-CD3/CD28. RESULTS: Using unsupervised data analysis tools, we observed no effect of the bilateral anterior quadratus lumborum nerve block on gene expression in immune cells (permutational multivariate analysis of variance using distance matrices: F=0.52, p=0.96), abundances of major immune cell populations (Wilcoxon rank-sum test: p>0.05), and stimulated cytokine secretion (Wilcoxon rank-sum test: p>0.05). CONCLUSIONS: Our study provides evidence that administration of bilateral anterior quadratus lumborum nerve block as a part of a multimodal analgesic regimen in an enhanced recovery after surgery for laparoscopic hemicolectomy in this cohort does not alter the systemic immune response.Trial registration number NCT03570541.