Comparative Study between Type II and Type III Ultrasound-guided Quadratus Lumborum Block for Anlgesia after Cesarean

INTRODUCTION

Neuraxial anaesthesia (mainly spinal anaesthesia) is the anaesthetic technique of choice for elective cesarean delivery, which lacks the advantage of prolonged analgesia ¹. Unrestricted mother mobility, minimum maternal and neonatal adverse effects, rapid return to baseline functionality, and early release home are all aims of optimal pain treatment following caesarean delivery., which are the fundamental of early rehabilitation after surgery (ERAS) protocol ².

Poor maternal bonding with the newborn, nursing difficulties and an increased risk of prolonged pain and postpartum depression are linked to suboptimal analgesia. The most commonly used analgesics in these cases are NSAIDs and opioids. Nevertheless, the use of these drugs is limited by the associated side effects ³.

The quadratus lumborum muscle block can be done in various ways, each termed after the anatomical location of the needle tip in respect to the quadratus lumborum muscle ⁴ . It does not only provide somatic analgesia, but also it can efficiently reduce visceral pain by spreading the local anaesthetic to the paravertebral space. This block effectively provides analgesia from T7 to L1 dermatomes ⁵.

However, many trials have approved the efficacy of QLB in abdominal surgery. Literature review reveals that few studies have compared the effectiveness of different QLB approaches. To our knowledge, this study will be the first trial to investigate the difference in efficacy between ultrasonography-guided QLB type 2 and type 3 in providing analgesia after Cesarean Delivery.

PATIENTS AND METHODS

This study a prospective randomised controlled double-blinded clinical study. The study was performed after approval of the institutional ethical committee, Al-Azhar University Hospital in Cairo. We took informed written consent from all parturient for participating in the study and for portraying the block technique.

After obtaining informed consent, 102 parturients who were scheduled for elective cesarean section under spinal anaesthesia were equally randomised into three groups; QL2, QL3, and no QL group. We include patients with physical status 1 or 2 as determined by the American Society of Anesthesiologists, as well as a normal singleton pregnancy with a gestation of at least 37 weeks. Patients suffering coagulopathy, anatomical anomalies, local infection, anticoagulant use, or inability to interpret or use the verbal rating pain score system or the patient-controlled analgesia (PCA) pump were excluded.

To estimate sample size, the MedCalc® version 12.3.0.0 programme "Ostend, Belgium" was used, as well as a statistical calculator based on a 95 percent confidence interval and study power of 80 percent with a 5 percent error. A previous study showed that the percentage of parturient required analgesia among the QL group at 12.5%, whereas the requirement was 41.6% among the second⁶. As a result, we computed the sample size based on these values. The smallest sample size required to detect a difference was 97 individuals. If a 5% drop-out rate is assumed, the sample size will be 102 cases, subdivided into three groups, Group P (n=34), Group A (n=34), and Group C (n=34).

The parturient were randomly assigned into one of the study three groups using a computer-generated table. Concealment was ensured using sealed envelopes.

For all parturients, Cesarean section was done under spinal anaesthesia with 0.5% heavy Marcaine alone with no adjuvants according to the guidelines.

QL block technique:

At the operation end, bilateral, ultrasound-guided QL block was performed in the groups (A) and (P) while the patient was in lateral decubitus positions. The probe was manipulated to scan structures under it and demonstrate the transverse process of L2 or L3 lumbar vertebrae, the erector spinae muscle, quadratus lumborum muscle, and psoas muscles. A spinal needle 9cm in length was advanced as described before, cautiously visualising the whole needle throughout the procedure. The tip of the needle was placed according to the desired site of injection.

After we had double-checked that the needle tip was in the right place, aspiration was done. We injected 0.4 ml/kg of 0.25% bupivacaine plus 2mg dexamethasone on each side, and the hydro-dissection of the injectate in the targeted place of lumbosacral fascia and adjacent structure were real-time portrayed. We calculate the drug dosage according to body weight by Omni lean body mass online calculator.  

In the posterior approach (QLB II), the needle tip was placed in the middle layer of the thoracolumbar fascia between the posterior border of the QL muscle and erector spinae muscle.

In the anterior approach (QLP III), the needle tip was passed through the QL muscle and placed at the anterior lumbosacral fascia between the quadratus lumborum and psoas muscles.

We take care not to exceed the maximum acceptable dose of bupivacaine by adjusting the total volume of local anaesthetic injected as 2mg/kg. 

Postoperative management:

The postoperative VAS score was assessed at T0, T2,4,8,12,16 and 24 hours and indicated when the patient requested analgesia. All parturients of all groups (ketorolac 30mg and paracetamol 10 mg/kg infusion over 10 minutes) started on patient request when VAS ≥4. We recorded the time for each intervention. We reassessed the patient VAS after 30 minutes of ketorolac-paracetamol administration. If the score was still ≥ 4, we gave an IV bolus of nalbuphine (4 mg) and may be repeated after 30 minutes if VAS was still ≥ 4. The patient was reevaluated 30 minutes again after the second dose of nalbuphine. If (VAS) remain ≥ 4 despite NSAIDs and two successive doses of nalbuphine, we consider a failure of that technique but the patient data inter our analysis. In the first 24 hours, we considered four doses of ketorolac-paracetamol as the Maximum doses allowed. If the patient needed additional analgesia, nalbuphine top-up doses up to (0.45mg/kg) (30mg /day) were allowed in an average weighted parturient of 70  but no more. In cases of the maximum dose of nalbuphine in addition to the maximum allowable doses of ketorolac-paracetamol had been reached, we considered the patients dropped out, and we did not analyse his data. The modified Bromage score will assess quadriceps muscle weakness ⁸. The parturient with a score of more than one was recorded and hourly observed until fading of the motor effect and observer satisfaction score was included in the patient follow up sheet, and the observer was requested to report his opinion.

Statistical analysis:

Recorded data were analysed using the statistical package for social sciences, version 23.0 (SPSS Inc., Chicago, Illinois, USA). We used the Kruskall Wallis test for multiple-group comparisons in non-parametric data and  F-one way analysis of variance when comparing more than two means. We used the Post Hoc test: Tukey's test for multiple comparisons between different variables. We used independent-samples: t-test of significance when comparing two means and Mann Whitney U test for two-group comparison in non-parametric data. We used the Chi-square test and Fisher's exact test to compare groups with qualitative data instead of the Chi-square test only when the expected count in any cell was less than five. We accept The 95% confidence interval and the 5% margin of error. So, the p-value was considered significant if it was <0.05, highly significant if it was <0.001, and non-significant if it was >0.05.

RESULTS

The results of the present study are demonstrated in the following tables.

We aimed by our study to investigate postoperative analgesic efficacy after cesarean section of Two different approaches of quadratus lumborum block; posterior (QLB 2) and anterior (QLB 3) approaches compared to the conventional intravenous.

Table 1: Comparison between studied groups according to heart rate (beat/min).

Table 2: Comparison between studied groups according to mean arterial blood pressure (mmHg).

Table 3: Comparison between studied groups according to VAS score.

Table 4: Comparison between studied groups according to time to first postoperative analgesia (minutes) of nalbuphine. There was a highly statistically significant difference between groups according to time to first postoperative analgesia (minutes) of nalbuphine with a p-value

Table 5: Comparison between studied groups according to the first postoperative analgesic time (minutes) of Ketorolac-Paracetamol. There was a highly statistically significant difference between groups according to the first postoperative analgesic time (minutes) of Ketorolac-Paracetamol with a p-value

Table 6: Comparison between studied groups according to total ketorolac and paracetamol consumption (dose/day). There was a highly statistically significant difference between groups according to total ketorolac paracetamol consumption (dose/day) with a p-value p

Table 7: Comparison between studied groups according to quantitative of nalbuphine. There was a statistically significant higher nalbuphine use in group C than in group P and A, with a p-value (p

Table 8: Comparison between studied groups according to satisfaction score. There was a statistically significant higher satisfaction score in group A and group P than group C, with a p-value (p