Lateral QL Block vs Intrathecal Morphine for Cesarean Section

Comparison of the Analgesic Efficacy of Lateral Quadratus Lumborum Block and Intrathecal Morphine for Postoperative Pain Management Following Cesarean Delivery Under Spinal Anesthesia: A Randomized Controlled Trial

Effective postoperative analgesia after cesarean delivery is essential for maternal recovery, early mobilization, breastfeeding, and maternal-infant bonding. Although intrathecal morphine (ITM) is considered the gold standard for post-cesarean analgesia, its use is associated with opioid-related adverse effects. Ultrasound-guided lateral quadratus lumborum block (QLB-I) has emerged as a promising alternative. This randomized, double-blind, non-inferiority trial aims to compare the postoperative analgesic efficacy of lateral QLB-I with ITM. Secondary outcomes include postoperative opioid consumption, pain scores, opioid-related adverse effects, quality of recovery (ObsQoR-11T), and maternal satisfaction.

Study Overview

• Status: Not yet recruiting
• Conditions: Postoperative Pain; Anesthesia; Regional Anesthesia
• Intervention / Treatment: Drug: ıv morphine PCA; Procedure: Lateral Quadratus Lumborum Block; Procedure: Intrathecal morphine

Detailed Description

Effective postoperative analgesia following cesarean delivery is essential not only for improving maternal comfort but also for facilitating early mobilization, breastfeeding, and maternal-infant bonding. Inadequate pain control has been associated with delayed mobilization, pulmonary complications, postpartum depression, and the development of chronic postsurgical pain (CPSP).

Intrathecal morphine (ITM) has long been regarded as the gold standard for post-cesarean analgesia, providing effective pain relief for 18-24 hours after a single dose. However, its use is limited by opioid-related adverse effects, including pruritus, postoperative nausea and vomiting (PONV), sedation, and urinary retention. These adverse effects may reduce maternal satisfaction and negatively affect breastfeeding and early mobilization.

In recent years, quadratus lumborum block (QLB) has emerged as an effective alternative for postoperative analgesia in abdominal surgery. Among the various QLB approaches, the lateral QLB-I technique has attracted considerable interest because of its ease of ultrasound-guided application, low incidence of motor block, and potential to provide extensive visceral and somatic analgesia. Previous studies have demonstrated that QLB can effectively attenuate both somatic and visceral pain, with cranial spread of local anesthetic along the thoracolumbar fascia reaching the ventral rami of the thoracic nerves (Blanco, 2015; Elsharkawy, 2019).

Randomized controlled trials in patients undergoing cesarean delivery have shown that QLB reduces postoperative opioid consumption, lowers pain scores, and improves patient satisfaction compared with control groups (Salama, 2020; Zhu, 2021). However, studies directly comparing QLB with ITM remain limited. Current evidence suggests that the analgesic efficacy of QLB may be comparable to that of ITM, although robust evidence demonstrating non-inferiority is still lacking.

Compared with ITM, the principal advantages of lateral QLB include the absence of motor blockade, the potential to reduce opioid-related adverse effects, and facilitation of early mobilization. Although ITM provides potent analgesia, demonstrating that the analgesic efficacy of lateral QLB is clinically equivalent within a non-inferiority margin not exceeding 10 mg intravenous morphine milligram equivalents (IV-MME) would represent a clinically acceptable outcome in terms of patient comfort and safety.

Accordingly, the primary objective of this study is to determine whether lateral QLB-I provides non-inferior postoperative analgesia compared with ITM. Secondary objectives include a comprehensive evaluation of adverse effects, quality of recovery using the ObsQoR-11T, and postoperative opioid consumption.

• Study Type: Interventional
• Enrollment (Estimated): 56
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Burhan Dost; Phone Number: +903623121919; Email: burhandost@hotmail.com
• Study Contact Backup: Name: Esra Turunc; Phone Number: +903623121919; Email: esra.kiymaz.ek@gmail.com

Study Locations

• Turkey (Türkiye)
  • Samsun, Turkey (Türkiye)
    • Ondokuz Mayis University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Women aged between 18 and 45 years.
• Singleton term pregnancy (≥37 weeks of gestation).
• American Society of Anesthesiologists (ASA) physical status II.
• Scheduled to undergo elective cesarean delivery via a Pfannenstiel incision.
• Planned to receive spinal anesthesia for cesarean delivery.
• Provision of written informed consent following a comprehensive explanation of the study.
• Sufficient cognitive capacity to understand and complete the study assessment instruments, including the Numeric Rating Scale (NRS) and the ObsQoR-11T.

Exclusion Criteria:

• Known allergy or hypersensitivity to any of the study medications, including morphine, bupivacaine, or fentanyl.
• Coagulopathy (international normalized ratio [INR] >1.5 or platelet count <100,000/mm³).
• Current treatment with anticoagulant or antiplatelet agents (e.g., heparin, low-molecular-weight heparin, or aspirin >100 mg/day).
• Infection, hematoma, or skin lesion at the planned block insertion site.
• Diagnosis of preeclampsia, eclampsia, or HELLP syndrome.
• Placenta previa, placenta accreta spectrum, or placental abruption.
• Gestational diabetes mellitus or chronic hypertension.
• Emergency cesarean delivery indicated because of fetal distress.
• Conversion to general anesthesia during cesarean delivery.
• History of chronic pain syndrome (e.g., fibromyalgia, lumbar disc herniation, or neuropathic pain).
• Regular use of opioids or psychotropic medications within the preceding 3 months.
• Diagnosis of epilepsy, severe anxiety disorder, or major depressive disorder.
• Obesity (body mass index >35 kg/m²).
• Severe systemic disease, including New York Heart Association (NYHA) class III or IV heart failure, hepatic or renal failure, advanced respiratory disease, or obstructive sleep apnea.
• Advanced pulmonary disease requiring continuous positive airway pressure (CPAP) therapy.
• Inadequate spinal anesthesia or the requirement for supplemental intraoperative analgesia.
• Surgical duration exceeding 120 minutes.
• Excessive intraoperative blood loss (≥1,000 mL) or the need for blood transfusion.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group QLB; LQLB (Active) + Sham ITM	Drug: ıv morphine PCA; A standardized IV PCA protocol will be initiated for all patients using a PCA device (Body Guard 575 pain manager, UK), programmed to deliver morphine boluses of 0.01-0.015 mg/kg (IBW), with a 6-minute lockout and a 4-hour maximum dose of 0.1-0.15 mg/ kg (IBW). No basal infusion will be used.; Other Names: PCA; Procedure: Lateral Quadratus Lumborum Block; Active Lateral QLB Local anesthetic: 0.25% bupivacaine, 0.4 mL/kg perside (maximum 30 mL per side). Maximum total dose: Bupivacaine ≤2.5 mg/kg (maximum approximately 150 mg). Timing: Immediately after completion of surgery. The patient will be positioned supine or in a slight lateral decubitus position. A high-frequency linear US transducer (5-12 MHz) will be placed on the anterolateral abdominal wall at the T12-L1 level. The fascial plane will be identified under ultrasound guidance. A 22-gauge, 100-mm needle will be advanced using an in-plane approach, and after negative aspiration, the local anesthetic will be injected incrementally with hydrodissection confirming correct spread. Sham ITM: The spinal anesthesia technique will be identical to that of the active ITM group. Morphine will be replaced with 0.2 mL preservative-free normal saline, while maintaining an identical syringe volume (2.7 mL) and appearance.; Other Names: Lateral QLB
Experimental: Group ITM; ITM (Active) + Sham QLB	Drug: ıv morphine PCA; A standardized IV PCA protocol will be initiated for all patients using a PCA device (Body Guard 575 pain manager, UK), programmed to deliver morphine boluses of 0.01-0.015 mg/kg (IBW), with a 6-minute lockout and a 4-hour maximum dose of 0.1-0.15 mg/ kg (IBW). No basal infusion will be used.; Other Names: PCA; Procedure: Intrathecal morphine; Hyperbaric 0.5% bupivacaine 12.5 mg, fentanyl 20 µg, and morphine 80 µg (0.08 mg). Spinal anesthesia will be performed at the L3-L4 or L4-L5 intervertebral space using a 25-gauge Quincke spinal needle. The study solution will be prepared to a total volume of 2.7 mL. Sham QLB Following completion of surgery, the patient will be positioned in the lateral decubitus position. The ultrasound transducer will be placed over the lateral QLB scanning window. A 22-gauge needle will be advanced into the skin and subcutaneous tissue only, without entering the fascial plane. To maintain procedural standardization and preserve blinding, 1-2 mL of normal saline will be injected into the subcutaneous tissue. Procedure duration, patient positioning, ultrasound probe placement, and dressing application will be identical to those used for the active lateral QLB-I procedure. A sterile dressing will be applied at the end of the procedure.; Other Names: ITM

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cumulative equivalent morphine consumption in the first 24 hours after surgery	The total dose of morphine administered via the patient-controlled analgesia (PCA) device, together with all rescue opioids administered during the first 24 postoperative hours following surgery, will be converted to morphine milligram equivalents (MME) using validated conversion factors and summed.	postoperative day 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cumulative equivalent morphine consumption in the first 48 hours after surgery	The total dose of morphine administered via the patient-controlled analgesia (PCA) device, together with all rescue opioids administered during the first 48 postoperative hours following surgery, will be converted to morphine milligram equivalents (MME) using validated conversion factors and summed.	postoperative day 2

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time of first analgesic request	Time at which the first analgesic is requested	postoperative day 1
The number of patients requiring rescue analgesics	The number of patients requiring rescue analgesics will be recorded over 24 hours.	postoperative day 1
Cumulative equivalent morphine consumption in the first 12 hours after surgery	The total dose of morphine administered via the patient-controlled analgesia (PCA) device, together with all rescue opioids administered during the first 12 postoperative hours following surgery, will be converted to morphine milligram equivalents (MME) using validated conversion factors and summed.	postoperative day 1
Postoperative pain scores	Pain status at rest and while activity will be assessed by NRS score at 0, 3, 6, 12, 24,36 and 48. hours after surgery. The NRS is an 11-point numeric scale that ranges from 0 to 10.	postoperative day 2
area under the NRS score curve (AUC) for resting	area under the NRS score curve (AUC) for resting and active 48 hours after surgery	postoperative day 2
Integrated Analgesic Score	Composite outcome integrating pain burden (AUC) and opioid consumption (IV-MME), expressed as the Integrated Analgesia Score (IAS), with lower scores indicating better overall analgesic efficacy.	postoperative day 2
Effective Analgesic Score	The Integrated Analgesia Score (IAS) will be calculated by jointly evaluating the mean pain scores (NRS, 0-10) and cumulative intravenous morphine milligram equivalent (IV-MME, mg) consumption over the 0-48-hour postoperative period.	postoperative day 2
ObsQoR-11T (Obstetric Quality of Recovery) score	A validated patient-reported outcome measure assessing the quality of postoperative recovery after cesarean delivery. The questionnaire consists of 11 items evaluating pain, physical comfort, physical independence, emotional state, and the ability to care for the newborn, with higher scores indicating better quality of recovery. Scores range from 0 to 110, with higher scores indicating better recovery. Assessments will be performed preoperatively (baseline) and at 24 and 48 hours postoperatively.	postoperative day 2
The number of patients requiring postoperative antiemetics.	The number of patients requiring treatment and PONV scores will be recorded in the post-anesthesia care unit (PACU) and at 3, 6, 12, 24, 36, and 48 hours postoperatively. PONV will be assessed using a 4-point scale: 0 = no nausea or vomiting; 1 = mild nausea; 2 = one episode of vomiting; and 3 = more than one episode of vomiting.	postoperative day 2
The incidences of post-operative pruritus	The presence and severity of pruritus will be assessed using a four-point scale where 0 indicates no pruritus, 1 indicates mild pruritus, 2 indicates moderate pruritus, and 3 indicates severe pruritus. A score of ≥1 will be considered the presence of pruritus.	postoperative day 2
Sedation score	Sedation levels will be assessed using the Pasero Opioid-Induced Sedation Scale (POSS) and recorded during the first 48 postoperative hours in the post-anesthesia care unit (PACU) and at 3, 6, 12, 24, 36, and 48 hours postoperatively. Sedation will be graded as follows: S = awake and alert; 1 = slightly drowsy, easily aroused; 2 = frequently drowsy, easily aroused, drifts off to sleep during conversation; 3 = somnolent, difficult to arouse; and 4 = minimal or no response to verbal or physical stimulation. Opioid-induced sedation will be defined as a POSS score ≥3 or a respiratory rate <8 breaths/min.	postoperative day 2
The incidences of Urinary retention	Number of patients with urinary retention (defined as failure to achieve spontaneous voiding within 8 hours after Foley catheter removal)	postoperative day 2
The morbidity of patients	The patients comorbidities will be assessed using the Charlson Comorbidity Index	Postoperative 1 month on an average
The number of patients with complications	The number of patients has any complications -directly related to the block or the drug used in the block- will be recorded	Postoperative 1 month on an average
Delayed onset of lactation	Delayed onset of lactation will be defined as the maternal report of milk coming in (based on subjective breast fullness and the transition from colostrum to mature milk) occurring more than 48 hours after delivery.	postoperative day 2
Apgar scores	Apgar scores at 1 and 5 minutes will be recorded. In addition, the need for neonatal intensive care unit (NICU) admission and any requirement for additional neonatal resuscitation will be documented.	postoperative day 1

Collaborators and Investigators

• Sponsor: Ondokuz Mayıs University
• Investigators: Principal Investigator: Burhan Dost, Ondokuz Mayıs University

Study record dates

Study Major Dates

• Study Start (Estimated): July 15, 2026
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: July 10, 2026
• First Submitted That Met QC Criteria: July 14, 2026
• First Posted (Actual): July 17, 2026

Study Record Updates

• Last Update Posted (Actual): July 17, 2026
• Last Update Submitted That Met QC Criteria: July 14, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: postoperative pain; cesarean delivery; intrathecal morphine; postoperative opioid consumption; lateral quadratus lumborum block
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain, Postoperative; Investigative Techniques; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Immunologic Techniques; Immunologic Tests; Skin Tests; Immune System Phenomena; Antigen-Antibody Reactions; Passive Cutaneous Anaphylaxis
• Other Study ID Numbers: VLQLBITM1

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No