Participants scheduled for elective cesarean sections under spinal anesthesia will be
divided into three groups: anterior Quadratus Lumborum block (QLB), intrathecal morphine,
and control groups, using the sealed-envelope randomization method. All participants will
receive detailed information and provide informed consent. Anesthesia for all patients
will be administered under spinal anesthesia. Spinal anesthesia will be performed with 12
mg of bupivacaine injected intrathecally at the L3-4 or L4-5 intervertebral space using a
25G spinocan needle.
In the intrathecal morphine group, 100 micrograms of morphine (0.1 mL) will be added to
the 12 mg of intrathecally administered bupivacaine. In the QLB and control groups,
intrathecal morphine will not be administered, and 0.1 mL of saline will be added to 12
mg of bupivacaine instead. In the anterior QLB block group, the block will be performed
postoperatively. Participants in the QLB group will be taken at the end of the surgery.
All blocks will be performed by the same anesthesiologist using ultrasound guidance. In
the Quadratus Lumborum block group, participants will be placed in the lateral decubitus
position. A convex ultrasound probe will be placed in sterile conditions along the
midaxillary line, in the subcostal area above the iliac crest, to visualize the quadratus
lumborum and psoas major muscles, as well as the L4 vertebral transverse process. Using
an in-plane technique, a 22G, 100 mm peripheral block needle will be advanced anterior to
the quadratus lumborum muscle and into the subfascial space between the quadratus
lumborum and psoas major muscles. After confirming the correct location with
hydrodissection, 20 mL of 0.25% bupivacaine will be injected slowly, observing the
fascial displacement on ultrasound. The same procedure will be repeated on the
contralateral side. All patients will be monitored in PACU for 30 minutes post-procedure.
The control and intrathecal morphine groups will not receive any postoperative
interventions. At the end of the surgery, once the modified Aldrete score is greater than
8, participants will be transferred to the ward due to the spinal anesthesia.
Postoperatively, when the spinal anesthesia level recedes by two dermatomes, patients
will receive 1g of intravenous paracetamol for analgesia. The postoperative analgesic
regimen will include paracetamol 1g every 6 hours (4x1g). In participants with NRS
(Numerical Rating Scale) scores greater than 3 during postoperative follow-up, 75 mg of
intravenous diclofenac sodium will be administered as rescue analgesia in the ward.
Diclofenac was not to be administered more than twice daily, and if the NRS score
remained ≥4 despite two doses, intravenous tramadol at a dose of 1 mg/kg was planned.
Participants will be evaluated at 2, 4, 8, 12, and 24 hours postoperatively by a blinded
anesthesiologist different from the one who performed the block. Resting and dynamic NRS
scores (rated on a scale of 0-10, where 0 indicates no pain and 10 indicates the most
severe pain; dynamic NRS scores will be assessed by asking the patient to cough) will be
recorded, along with the total amount of analgesics used in the first 24 hours
postoperatively, and the incidence of nausea, vomiting, and pruritus will also be
evaluated.