Comparative Study between Ultrasound Guided Quadratus Lumborum Plane Block Versus Ultrasound Guided Erector Spinae Plane Block for Postoperative Pain Relief in Patients undergoing Elective Caesarean Section

 INTRODUCTION

One of the most prevalent surgical procedures in the globe is a Caesarean section (CS). Both the mom and the newborn suffer from post-operative pain, especially in the first 48 hours following delivery.  ¹

Suboptimal analgesia has been linked to delayed functional recovery, delaying mobilization that might raise the risk of thromboembolic complications, weak mother-newborn bonding, breastfeeding problems, and an increased risk of persisting pain as well as postpartum depression. NSAIDS and opioids are the most commonly used analgesics. Nevertheless, the use of these drugs is limited by the associated side effects. ²

Blanco described the quadrates lumborum block (QLB) for the first time in 2007 ³. The main advantage of QLB over transverse abdominis plane block is that the local anesthetic agent is extended beyond the transverse abdominis plane to the thoracic paravertebral region. The greater the diffusion of local anesthetic agents, the broader the analgesic effect, and the longer the duration of the

administered local anesthetic solution's action. Prior studies indicated that QLB might reduce opioid requirements in the postoperative period. ⁴

The erector spinae plane block (ESPB) is an interfacial plane block that was initially described as an effective therapeutic approach for thoracic neuropathic pain by Forero et al in 2016 ⁵. ESP blocks are being used as one of the pain treatment techniques for patients of all generations (newborns, infants, children, adolescents, and adults) having abdominal and thoracic surgeries with minimal complications compared to opioid consumption. ⁶

PATIENTS AND METHODS

Study Design: prospective randomized controlled single blinded clinical study.

Ethical Considerations: The study was performed with the agreement of the Al-Azhar University Hospitals' institutional ethical committee in Cairo. All parturients gave written informed consent to participate in the research.

Eligibility Criteria and Assignment:

Following informed agreement, 50 pregnant women preparing for an elective cesarean delivery with spinal anaesthetic have been randomly assigned to one of two groups; QLP group and ESP group. We excluded patients with known hypersensitivity to study drugs, American Society of Anesthesiologists (ASA) class III and IV, [BMI]≥30kg/m², emergency operations, coagulation disorders and thrombocytopenia, infection at the injection site and insertion of needle, and patients' further refusal to participate in the study.

Randomization: Patients have been allocated to one of the study groups at random using a computer-generated table, with the randomized sequence hidden in sealed opaque envelopes.

Sample size: The sample size was calculated using Epi-Info software statistical package created by World Health organization and center for Disease Control and Prevention, Georgia, USA version 2002. The sample size was calculated at n=25 per each group. The criteria used for sample size calculation were as follows: 95% confidence limit, 80% power. Patients were randomized into 2 groups to receive either Quadratus lumborum block (QLB Group) or erector spinae block after spinal anesthesia (ESB). Each group constitute of 25 patients (n=25):

QLB Group: All members of this group were received bilateral quadratus lumborum block after spinal anesthesia at end of operation. The QLB was performed by using bupivacaine 0.25% (20 ml in eachside).

ESB Group: All members of this group were received bilateral erector spinae block after spinal anesthesia at end of operation. The ESB was performed by using bupivacaine 0.25% (20 ml in eachside).

Induction of anesthesia: For all patients, On arrival to the operative theatre monitor were be attached to the patient to display ECG, heart rate, non-invasive mean arterial blood pressure and oxygen saturation.Cesarean section was done under spinal anesthesia with 0.5% (2.2ml) heavy Marcaine.

QL block technique: Ultrasound guided QLB was performed by placing the patient in a lateral posture with the side that was to be anaesthetized turned upward. Skin and transducer preparation was done. The sterilized gel sufficiently coated the transducer ultrasound. The needle inserted from the posterior to anterior, toward the intersection of the tapering transverse abdominis muscles and the lateral border of the QL muscle. The transverses abdominis muscle's aponeurotic connection was then penetrated, and local anesthetic was deposited in the lateral border of the QL muscle at the intersection with the transversalis fascia (a possible area medial to the abdominal wall muscles and anterolateral to quadrates lumborum muscle).

ES Block technique: The ultrasound-guided ESB was performed by placing the patient in a lateral posture, having the side to be injected turned upward. A high-frequency linear ultrasound transducer had been sagittally positioned against thoracic vertebra 12 (T12) in the lateral posture and moved about 3-cm lateral to the spinous process of the spine. The tip of the transverse processes and the erector spinae muscle have been recognized, and a needle has been progressed in a plan from cephalic to caudal via the interfascial plane between the erector spinae and the underlying transverse process, followed by the injection of local anesthetic into the space between the two.

Postoperative measurements: Heart rate, Mean arterial blood pressure. Oxygen saturation was recorded before induction of spinal anesthesia, every 10 minutes intraoperatively and in PACU, then at 1,2,4,8,12,24 hours postoperatively. Patient satisfaction, Time of first analgesia required by the patient. Total amount of analgesia consumption (morphine) were be collected and recorded at the end of the 24 post-operative hours. Acute postoperative somatic and visceral pain within the first 24 hours postoperatively were assessed by using VAS (0-10) where 0=no pain, 10=worst pain at PACU and postoperative patient room at 1,2, 4,8,12,24hours postoperatively. For all patients of the two groups, ketolac (30mg iv infusion was given every 12 hours) rescue pain analgesia was given postoperatively for visual analogue scale (VAS)≥4 by morphine (.05mg/kg iv). VAS was reassessed 15 minutes later to any rescue analgesic injection.

Statistical analysis: The statistical package for social sciences, version 22.0, has been employed to analyze the data that has been collected (SPSS Inc., Chicago, Illinois, USA). The mean ± standard deviation (SD) of quantitative data is used (SD). The median, or frequency and percentage, of qualitative data are used. When comparing two means, the independent-samples t-test has been employed to determine significance. Mann-Whitney U test: used in non-parametric data for two-group comparisons. When comparing percentages between two qualitative variables, the Chi-square (x2) test of significance has been applied. The margin of error accepted is 5%, with a confidence interval of 95%. As a result, a P value of < 0.05 is deemed significant, whereas a P value of < 0.001 is regarded as highly significant.

RESULTS

The following tables and figures show the findings of the current research.

Table 1: Comparison of the studied groups based on demographic data.

Table 2: Comparison of study groups based on intra-operative mean arterial blood pressure (mmHg).

Table 3: Comparison of study groups based on intraoperative heart rate

Table 4: Comparison of study groups based on postoperative mean arterial pressure (MAP).

Table 5: Comparison of study groups based on postoperative heart rate.

Table 6: Comparison of study groups based on post-operative VAS.

Table 7: Comparison between studied groups according to pain assessment.

There is no statistically significant difference in mean arterial pressure or heart rate between the two groups. Furthermore, there was no statistically significant difference in postoperative mean arterial pressure or postoperative heart rate between the two groups.

Regarding pain assessment, no statistically significant differences exist between QLB and ESB regarding VAS score, morphine consumption, time of analgesia, and patient satisfaction.