Lateral Quadratus Lumborum Block Versus Transversus Abdominis Plane Block in Laparoscopic Surgery
Lateral Quadratus Lumborum Block Versus Transversus Abdominis Plane Block in Laparoscopic Surgery
The transversus abdominis plane (TAP) block is an already established technique and is
 considered now as an efficient part of the multimodal pain management approach for abdominal
 surgical procedures. The quadratus lumborum block (QLB) is a recently described regional
 block that was first described by Blanco et al , which has been reported to provide an
 effective analgesia for upper and lower abdominal surgeries. The aim of this study is to
 compare the analgesic efficacy of TAP block and QLB 1 after laparoscopic abdominal surgery
 regarding opioid consumption, duration of analgesia and visual analog score.

 This prospective randomized controlled observer-blinded study compared between the analgesic
 efficacy between TAP block (n=25) versus QL block (n=25) in patients aged (18-60) years of
 American society of anesthesiologists physical status class I & II scheduled for elective
 laparoscopic abdominal surgical procedures. The primary outcome was the cumulative morphine
 consumption at first 24 hours postoperatively. Secondary outcomes included VAS scores, first
 analgesic requirements and any postoperative complications
This prospective randomized, observer-blinded paralleled groups study was conducted following
 the tents of the Declaration of Helsinki. This study was approved by the local institutional
 ethics committee and local institutional review board of Fayoum university hospital and
 written informed consent was obtained from 50 adult patients scheduled for elective
 laparoscopic abdominal surgical procedures (inguinal hernia repair-missed IUCD
 extraction-appendectomy-ovarian vein ligation) between July 2019 and February 2020.

 Patients were randomly allocated into two groups (QLB group n=25 and TAPB group n=25) using
 computer generated random numbers kept in separate opaque envelopes that were opened by the
 study investigator just before the block. The patient and the data collector were unaware of
 the group allocation till the end of the study.

 Pre-operative assessment (History, examination and investigations) was done (according to the
 local protocol designed to evaluate the patients). Demographic characteristics: age, weight,
 height and BMI were recorded in preoperative assessment of patients. All patients received
 150 mg Ranitidine oral tablet at night and on the morning just before the operation as a
 premedication. Before surgery, the participants received education about the VAS pain score
 (0-10) (where 0 = no pain and 10 = worst comprehensible pain) and the details of the nerve
 block procedures. After a 6 hrs fasting, the patients were taken to the operation theatre.

 Upon arrival to the operating room standard monitors (Pulse oximeter, noninvasive blood
 pressure monitoring, capnography and electrocardiogram) were applied and continued all over
 the operation, an 18 gauge peripheral intravenous (IV) cannula was inserted, IV midazolam
 0.03 mgkg-1, metoclopramide 10 mg, and ceftriaxone 1 gm were administered to all patients as
 premedication then pre-oxygenation with O2 100% for at least 3 min then induction of
 anesthesia was done with fentanyl 1μgkg-1, propofol 1.5-2 mgkg-1 and atracurium 0.5 mgkg-1.
 Anesthesia was maintained by volume controlled ventilation (VCV) tidal volume 6-8 mlkg-1 with
 oxygen and air (50:50) with target of EtCO2≈ 35-40 mmHg, isoflurane 1:1.5 % volume
 concentration and atracurium 0.1 mgkg-1 every 20-30 minutes.

 The study solution was prepared in two syringes each contained 20 ml of bupivacaine 0.25%. By
 the end of surgery and before recovery from general anesthesia, either blocks were done using
 a high-frequency ultrasound probe Active Array L12-4 (8-13MHz) of an ultrasound machine
 (Philips clear vue350, Philips healthcare, Andover MA01810, USA) and a 22-gauge, 50 mm
 echogenic needle (Stimuplex D; B Braun, Germany).

 For the ultrasound-guided quadratus lumborum block group, the patient was placed in lateral
 position and skin sterilization was done with povidone iodine. Then a high frequency linear
 probe was placed above the iliac crest to recognize the three layers of the abdominal wall
 muscles. Transversus abdominis was traced posteriorly until the transversus aponeurosis
 appeared, then the probe tilted slightly caudal to enhance the appearance of transversus
 aponeurosis. QL was identified medial to the aponeurosis of transversus abdominis muscle.
 Then the needle was inserted from supero-anterior to postero-inferior and advanced using in
 plane technique till the needle tip reached the anterolateral border of the QL at its
 junction with transversalis fascia. After negative aspiration (to exclude intravascular
 injection), the correct needle position was confirmed by hydrodissection using 1mL of normal
 saline. Then 20 mL of 0.25% bupivacaine was applied. The same technique was performed on the
 other side.

 For the ultrasound-guided TAP block, skin sterilization was done with povidone iodine. The
 probe was placed in the mid-axillary line above the level of the anterior superior iliac
 spine, then slided cranially till the three abdominal wall muscles identified (External
 oblique muscle (EAO), internal oblique muscle (IOM) and transverse abdominis muscle (TAM)).
 The needle was advanced using in-plane technique till it reached the transvers abdominis
 plane between the IOM and TAM, the correct needle position was proved by hydrodissection
 using 1 mL of normal saline. An injection of 20 mL of 0.25% bupivacaine was applied. The same
 technique was performed on the other side.

 After performing the block anesthesia was discontinued and tracheal extubation was done once
 the patient fulfilled the extubation criteria. Patients were transferred to post-anesthetic
 care unit (PACU), where they were discharged from the PACU after a modified Aldrete score≥9.
 Visual analogue scale (VAS) was used to assess postoperative pain. All patients received
 analgesics according to the local institutional protocol as following (paracetamol 1gm IV
 infusion/8 hrs and ketorolac 30 mg IM/12 hrs.). A postoperative rescue analgesia with
 morphine sulfate IV was given to patients with VAS >4 at a bolus dose of 3 mg increments with
 a maximum dose of 15mg per 4 hours or 45mg per 24 hours.

 Sample size was estimated using G*Power© software version 3.1.9.2 (Institute of experimental
 psychology, Heinrich Heine University, Dusseldorf, Germany)149 with total opioid consumption
 among the two groups as the main primary outcome. Previous similar researches150 demonstrated
 that the effect size between the two groups was expected to be large of 1.12 and it
 calculated that 42 patients (21 patients per group) would provide to achieve a power of 95%
 with type I error rate of 0.05. However, we assigned 50 patients (25 patients per group) to
 compensate for data loss. The collected data were organized, tabulated and statistically
 analyzed using SPSS software statistical computer package version 22 (SPSS Inc, USA). Data
 were tested for normality using shapiro-wilks test. Numerical variables such as age, body
 weight, height and BMI were normally distributed and were described as mean ± standard
 deviation (SD). An independent t-test was used to compare the mean values of the two groups.
 Other variables were not normally distributed and were presented as median and interquartile
 range (IQR); Mann-Whitney U test was used as a test of significance. The time-to-event
 variable (time to analgesic request) was evaluated using the Kaplan-Meier method, and the
 logrank test was used to compare the groups. Qualitative data were presented as numbers and
 percentages, and the chi-squared test was used to determine significance. A two-sided P-value
 of <0.05 was considered statistically significant.
Inclusion Criteria:

 -  Patients scheduled for elective laparoscopic abdominal surgeries (inguinal hernia
 repair-missed IUCD extraction-appendectomy-ovarian vein ligation)

 -  Patient aged 18-60 years

 -  American Society of Anesthesiologists Physical Status I or II.

 Exclusion Criteria:

 -  Patient refusal

 -  Body mass index (BMI) > 40 kilogram/square meter

 -  Contraindication to regional anesthesia (coagulopathy, allergy to local anesthetic,
 sever thrombocytopenia or infection at puncture site)

 -  Sepsis

 -  Chronic pain condition requiring the intake of opioids at home

 -  Any significant neurological, cardiovascular or respiratory disease.