COMPARISON OF LEVOBUPIVACAINE AND ROPIVACAINE IN QUADRATUS LUMBORUM BLOCK FOR POSTOPERATIVE ANALGESIA AFTER ABDOMINAL SURGERY

INTRODUCTION

Patients, who will have major abdominal surgery, need serious pain management at the postoperative period. Many trials revealed that, conventional pain management with intramuscular analgesics is insufficient for many patients. Postoperative pain remains a concern following surgery and is a source of morbidity, increased hospital stay, and dissatisfaction.

In the search for the wider analgesia coverage and long-lasting postoperative analgesia have been developed. Quadratus lumborum (QL) block, first reported in 2007 by Blanco, is a posterior abdominal wall block which permits spread of local anaesthetic agent behind the quadratus lumborum muscle into a triangular space known as a lumbar interfascial triangle which lies beside the middle layer of the thoracolumbar fascia.¹ This interfascial plane is in adjoining proximity with numerous sympathetic fibres and conjoin with the thoracic paravertebral space, thus preceding to a long-standing block with the capability to provide visceral analgesia.^2,3 Various studies are there showing effective post-operative analgesic profile of QL block.^4-6

Since the initial description, the block has experienced several modifications and today four types of the block are performed, which differ by the site of drug application. These are QLB 1 or lateral QLB, QLB 2 or posterior QLB, QLB 3, or anterior/transmuscular QLB, and QLB 4 or intramuscular QLB. Quadratus lumborum block 2 implies the application of medication on the posterior side of the QLM between the QLM and the medial lamina of TLF which separates QLM from the latissimus dorsi muscle and paraspinal muscles [erector spinae muscles (ESM)]. This is laterally from the attachment of IOM aponeurosis, in the to the so-called lumbar interfascial triangle.

Although the evidence base is weak and still growing, the data thus far suggest that quadratus lumborum block potentially results in extensive sensory blockade (T7–L2). Quadratus lumborum block may lead to dermatomal coverage required for abdominal surgery and hip surgery, representing an avenue for future research.^4,7

Ropivacaine and levobupivacaine, the newer long-acting LA agents and S (−) isomers with a favourable safety profile, were introduced into clinical practice. It has been recently demonstrated that levobupivacaine contributes a different clinical profile because of its high lipophilic and vasoconstrictor properties compared to ropivacaine. Ropivacaine is about 40% less potent than racemic bupivacaine, while levobupivacaine has the same potency of racemic bupivacaine.⁸

Levobupivacaine is the S(-) enantiomer of bupivacaine, a long acting amino-ester local anaesthetic agent. Levobupivacaine is the LA agent with a higher threshold for systemic toxicity and with lesser cardiac and central nervous system side effects. Single-shot regional anaesthesia using levobupivacaine has a long duration of analgesia compared to ropivacaine.⁷

Ropivacaine, is the local anesthetic with a better toxicity profile compared with alternatives, such as bupivacaine, is currently considered the safest, long-acting local anesthetic available in the market. Two trials comparing the plasma concentration after intravenous use of ropivacaine versus bupivacaine have demonstrated that ropivacaine requires a higher plasma concentration before toxicity develops.  Previous studies of peripheral nerve blocks (PNBs) with levobupivacaine have suggested that the duration of analgesia of levobupivacaine might be longer than that of an equivalent dose of bupivacaine or ropivacaine.⁹  So, we hypothesized that levobupivacaine will increase the time to rescue analgesia in comparison to ropivcaine in quadratus lumborum block too. In this study, we will compare levobupivacaine and ropivacaine in quadratus lumborum block for postoperative analgesia after abdominal surgery.

AIMS AND OBJECTIVES

AIM:

•      To compare Levobupivacaine and Ropivacaine in quadratus lumborum block for postoperative analgesia after abdominal surgery

OBJECTIVES

Primary Objective:

•      To study duration of analgesia i.e. time needed for  first rescue analgesia in postoperative period.

Secondary Objectives:

•      Total  rescue analgesic consumption in postoperative period

•      Postoperative pain scores using the visual analog scale (VAS) for pain at rest in the postoperative period at 0, 1, 6, 12, and 24 hours.

•      Postoperative patient’s hemodynamics by mean blood pressure and heart rate at 0, 1, 6, 12, and 24 hours.

•      Incidence of nausea and vomiting

•      To compare complications if any

MATERIAL AND METHODS

Study setting:

The study will be conducted in Department of Anesthesiology, King George’s Medical University, Lucknow after written informed consent will be obtained from either of the patients/Guardian.

Study duration : One year 

Study design:

Randomized parallel study

Sample size:

76

Inclusion Criteria:

·         Patients giving written consent will be taken

·         Patients of either sex aged 18-65 years

·         ASA I-II patients scheduled to undergone

Exclusion Criteria:

·         Local infection at site of block

·         Cardiovascular disease

·         H/o allergy to study medications

·         known hypersensitivity to LA

·         body mass index ≥35 kg/m², ≤16kg/m²

·         history of opioid addiction

·         bleeding diathesis

·         renal and hepatic dysfunctions

·         pregnancy

Methodology:

The study will be conducted after getting approval from ethics committee of King Georges Medical University, Lucknow after taking patient’s consent. A computer system will be used for randomization by creating a list of number each number referred to one of the two groups. Block randomization will be used to ensure equality of the groups. The patient’s will be divided into 2 groups using opaque sealed envelope technique. 

Group A : All patient received 0.25% Levobupivacaine with quadratus lumborum block

Group B:  All patients received 0..375% Ropivacaine  with quadratus lumborum block

A detailed preoperative check-up will carried out one day before surgery. The patients will explained in detail about the anaesthesia procedure. The patients will kept fasting as per institutional protocol (2 h for clear liquid and 6 h for semisolid and solid) before surgery. The patients will pre-medicated with tablets alprazolam 0.5 mg and pantoprazole 40 mg previous night of surgery.

In the operation theatre, an intravenous (IV) cannula of 18 G will be secured in non-dominant hand and ringer lactate at a rate of 10 ml/kg started. The standard ASA monitors in the form of electrocardiogram (ECG), pulse oximetry (SpO2), non-invasive blood pressure (NIBP) will be applied and baseline vital parameters will be recorded. All patients  will be given general anesthesia.

After attaching ASA standard monitors patients will be preoxygenated with 100% oxygen and premedicated with glycopyrolate  0.2mg/kg and fentanyl 2mcg/kg and anesthesia will be induced with propofol 2mg/kg inj., Vecronium 0.1mg/kg as muscle relaxant then airway will be secured  with endotracheal tube according to the weight of the patient and maintenance of anesthesia will be done with oxygen  and nitrous oxide(1:1), vecronium, fentanyl and sevoflurane. After the completion of surgery quadratus lumborum block will be performed bilaterally in both groups. For patients randomized to the study group, a curvilinear ultrasound probe will be placed in the posterior‐axillary line, right above the iliac crest to identify the transversus abdominis, quadratus lumborum, and psoas muscles. Using sterile technique, a 22 gauge  needle will be inserted and advanced under ultrasound guidance below the fascia covering of the QL muscle, with the tip of the needle ending between the psoas and QL muscles. The optimal point of injection will be determined using hydrodissection with 2 ml of 0.9% normal saline (NS). After correct tip placement, the drug will be injected in 5 ml increments with intermittent aspiration. During the injection, the distribution of LA will be observed as a hypoechoic enlargement on ultrasonography The group A will be given 20 ml of 0.25% inj. levobupivacaine on both sides of abdomen and group B  will be given 20 ml of 0.375% inj. ropivacaine with a total volume of 20 ml both sides of abdomen.

Duration of analgesia i.e. time to first rescue analgesia after surgery will be recorded. The HR, NIBP, SpO2 and respiratory rate (RR) will be recorded in the first 24 hrs. and other parameters like total analgesic consumption in postoperative period, postoperative pain scores using the visual analog scale (VAS) for pain at rest in the postoperative period at 0, 1, 6, 12 and 24 will be observed. If any patient will have VAS > 3, Inj Tramadol 2mg/kg will be given as first rescue analgesic and if after giving Tramadol, VAS will not decrease less than four within 30 minutes Inj Diclofenac will be used as second rescue analgesic. Adverse effects including nausea, vomiting, hypotension, bradycardia, arrhythmia any complications (LA toxicity)  till 24 h after surgery will be compared in both groups. The patient satisfaction will be graded as poor (1), fair (2), good (3), excellent (4).

Sample Size

The sample size formulae used are as follows: ¹⁰

**Risk of rate of post operative rescue analgesia in QL block group vs. Control group. 

Statistical analysis:

Data will be entered in Microsoft excel and analyzed using statistical software SPSS version25(Chicago, IL, USA). Student’s t test will be used to analyze parametric data, while the Mann-Whitney U test was applied to non-parametric data and Fisher’s test to categorical data. P values < 0.05 will be considered statistically significant.

Ethical approval:

It will be taken from the Institutional Ethics Committee of the university.  

REVIEW OF LITERATURE

Kumar GD  et al (2018)¹² conducted a prospective, randomized, double-blinded study total 70 adult patients were randomly allocated into two groups, where Group A received TAP block with 20 ml of 0.25% ropivacaine on each side (n = 35) and Group B received QL block with 20 ml of 0.25% ropivacaine on each side (n = 35). The time of block, duration of surgery, Numerical Pain Intensity Scale (NPIS) score at the 1st, 2nd, 4th, 8th, 12th, 16th, and 24th postoperative hours, and the total analgesic drug requirements were noted and compared between the two groups. The time for first analgesic requirement was 243.00 ± 97.36 min and 447.00 ± 62.52 min and the total analgesic consumption (morphine in mg) was 5.65 ± 1.55 and 3.25 ± 0.78 in Group A and Group B, respectively, both of which were statistically significant (P<0.01). There was a significant difference in postoperative pain scores (NPIS scale 0–10) at rest, between the two groups, up to 16 h. Patients who received QL block had a significant improvement in postoperative pain relief with reduced consumption of opioids.

Deng W  et al (2019)¹³ conducted a study that total 74 patients scheduled for laparoscopic colorectal surgery were randomly assigned into 2 groups. After surgery, patients received bilateral ultrasound-guided single-dose of QLB or TAPB. Each side was administered with 20 ml of 0.375% ropivacaine. All patients received sufentanil as patient-controlled intravenous analgesia (PCIA). Resting and moving numeric rating scale (NRS) were assessed at 2, 4, 6, 24, 48 hours postoperatively. The primary outcome measure was sufentanil consumption at predetermined time intervals after surgery. Patients in the QLB group used significantly less sufentanil than TAPB group at 24 and 48 hours (P < .05), but not at 6 hours (P = .33) after laparoscopic colorectal surgery. No significant differences in NRS results were found between the two groups at rest or during movement (P > .05). Incidence of dizziness in the QLB group was lower than in TAPB group (P < .05). The QLB is a more effective postoperative analgesia as it reduces sufentanil consumption compared to TAPB in patients undergoing laparoscopic colorectal surgery.

Wang Y et al (2021)¹⁴ evaluated the effect of ultrasound-guided quadratus lumborum block (QLB) preemptive analgesia on recovery in colon cancer patients undergoing open radical surgery in 56 patients. Patients were divided into two groups: Group Q (n=27), which received QLB combined general anesthesia, and Group C (n=29), which received general anesthesia only. Both groups were given self-controlled intravenous analgesia pump after surgery. The primary outcome is a series of parameters representing postoperative recovery. The secondary outcome was VAS scores and opioid consumption. The rest and active VAS scores were significantly lower in Group Q (P<0.01). The opioids consumption was significantly decreased in Group Q (P<0.05).

Murouchi, T, et al (2016)¹⁵ conducted a study that total II patients scheduled for laparoscopic ovarian surgery under general anesthesia. The patients received bilateral single-injection QLBS (20 mL of 0.375% ropivacaine per side). Arterial blood was sampled at 10, 20, 30, 45, 60, 90, and 120 minutes after ropivacaine administration. The results were retrospectively compared with the results of our previous study on lateral TAPB. The median duration of analgesia after QLB exceeded 24 hours and was significantly longer than the duration of lateral TAPB (P = 0.003). Quadratus lumborum block affected the T7-T12 dermatomes, whereas TAPB affected T10-T12. Arterial ropivacaine levels after block peaked at comparable time in the QLB and lateral TAPB groups (Tmax: 35 [SD, 13] vs 35 [SD, 11] minutes; P = 0.93). Peak ropivacaine concentrations were significantly lower in QLB than in lateral TAPB (Cmax: 1.0 [SD, 0.5] vs 1.8 [SD. 0.4] µg/mL; P = 0.0003). Quadratus lumborum block resulted in a widespread and long-lasting analgesic effect after laparoscopic ovarian surgery and resulted in lower peak arterial ropivacaine concentrations as compared with those of lateral TAPB after 150 mg ropivacaine injection.

Malav K,  etal (2018)¹⁶ conducted a prospective double-blind, randomised study was carried out in 100 patients of either sex, aged between 20 to 60 years, and American Society of Anesthesiologist (ASA) grades I and II. Patients were randomly allocated into groups R and L of 50 each with 0.5% ropivacaine and 0.5% levobupivacaine, respectively, for sciatic nerve block using the Labat approach. They assessed the onset and duration of sensory and motor block, duration of analgesia, consumption of analgesic, and any untoward effect over 24 hours. Both the groups were comparable with regard to demographic variables and onset of sensory and motor block (p>0.05). Group L compared to group R had significantly longer median (95% confidence interval) duration of sensory block (647.50 min [624.99–674.41] vs. 535 min [524.77–559.83], respectively; p<0.0001) as well as motor block (1065.0 min [1054.5–1068.90] and 945 min [947.13–1013.30], respectively; p<0.0001). Postoperative analgesia also lasted significantly longer in group L compared to group R (1320 min [1273.4–1321.8] vs. 840 min [759.23–812.77]; p<0.0001]). Patients in group L had significantly better visual analogue scale (VAS) score and lesser consumption of analgesics (p<0.0001). None of the groups developed any adverse effect over the observation period. Levobupivacaine provides prolonged postoperative analgesia in sciatic nerve block with reduction in postoperative analgesic consumption.

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14.                        Wang Y, Hu H, Feng C, Liu D, Ding N. Effect of Ultrasound-Guided Quadratus Lumborum Block Preemptive Analgesia on Postoperative Recovery of Patients with Open Radical Colon Cancer Surgery: A Retrospective Study. Cancer Manag Res. 2021 Sep 1;13:6859-6867.

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