Quadro-Iliac Plane Block Versus Wound Infiltration for Postoperative Pain After Single-Level Lumbar Discectomy

Investigation of the Effects of Quadro-Iliac Plane Block and Wound Infiltration on Postoperative Acute Pain After Single-Level Lumbar Discectomy Surgery

This prospective observational study aims to compare the effects of the Quadro-Iliac Plane Block (QIPB) and wound infiltration (WI) on postoperative acute pain in adult patients undergoing elective single-level lumbar discectomy. QIPB is a newly introduced ultrasound-guided fascial plane block, and it is currently being used in routine clinical practice in our anesthesiology department as part of postoperative analgesia for lumbar spine surgery. Wound infiltration is a conventional method in which local anesthetic is injected into the surgical field at the end of the procedure.

In this study, eligible patients will be monitored prospectively without randomization or alteration of standard care. Postoperative pain scores, opioid consumption, nausea and vomiting, patient satisfaction, and recovery parameters will be evaluated during the first 24 hours after surgery. The study aims to provide real-world clinical evidence comparing these two analgesic techniques in lumbar discectomy patients.

Study Overview

• Status: Completed
• Conditions: Regional Anaesthesia; Postoperative Pain Management; Lumbar Discectomy

Detailed Description

This prospective observational study aims to evaluate and compare the postoperative analgesic outcomes of two routinely used analgesic techniques-Quadro-Iliac Plane Block (QIPB) and wound infiltration (WI)-in adult patients undergoing elective single-level lumbar discectomy. Both QIPB and WI are standard components of postoperative pain management in our hospital, and the type of analgesic technique administered to each patient is determined solely by the attending anesthesiologist based on routine clinical judgment. The research team does not influence clinical decision-making, perform block procedures, or modify any aspect of patient care. All interventions included in this study reflect standard institutional practice.

The primary objective is to compare cumulative opioid consumption during the first 24 hours after surgery between patients receiving QIPB and those receiving WI. Secondary objectives include evaluating postoperative pain scores, early recovery parameters, patient satisfaction, postoperative nausea and vomiting (PONV), rescue analgesic requirements, block-related complications, and hospital length of stay.

Clinical Routine and Analgesic Protocol

All patients will be managed according to the standard multimodal analgesia protocol routinely used in our neurosurgery operating room. Intraoperatively, intravenous tenoxicam 20 mg, tramadol 100 mg and dexamethasone 8 mg will be administered as part of routine analgesic and antiemetic care. Paracetamol 1 g IV will be given at the end of surgery and continued at regular intervals postoperatively. Rescue analgesia will consist of intravenous tramadol 100 mg infused over 30 minutes, with a maximum daily dose of 300 mg; if pain remains uncontrolled (NRS ≥4). All patients will receive intravenous morphine patient-controlled analgesia (Body Guard 575 Pain Manager) with a standard setting of 1 mg bolus dose, a 10-minute lockout interval, and a 4-hour limit set to 80% of the maximum allowable dose.

Block Techniques (Performed as Part of Routine Care)

QIPB Group:

QIPB is a newly introduced interfascial block technique currently used in our clinic for postoperative lumbar spine analgesia. At the end of surgery and before extubation, the patient is placed in the prone position. A low-frequency convex ultrasound probe (2-6 MHz) is positioned at the L3 midline in the transverse plane to identify the spinous process. The probe is then moved laterally and caudally to visualize the attachment of the quadratus lumborum muscle to the iliac crest. Under ultrasound guidance, a 22G, 100-mm block needle is advanced into the fascial plane between the quadratus lumborum and erector spinae muscles. A total of 60 mL of 0.25% bupivacaine (30 mL per side) is injected bilaterally. The procedure is performed by experienced anesthesiologists as part of normal clinical practice.

Wound Infiltration Group (WI):

WI is a routine analgesic method performed in our operating room. At the end of surgery, before skin closure, 20 mL of 0.25% bupivacaine is infiltrated into the surgical field in multiple tissue layers. This procedure is performed entirely according to the attending anesthesiologist's habitual clinical practice.

Postoperative Assessment

Postoperative pain will be assessed using the 11-point Numeric Rating Scale (NRS; 0-10) at rest and during movement (deep breathing or coughing) at 0, 3, 6, 12, and 24 hours after surgery. PONV will be evaluated using a verbal descriptive scale. If PONV score is ≥3, 4 mg IV ondansetron will be administered. Patient satisfaction and quality of recovery will be assessed using the Turkish version of the QoR-15 questionnaire preoperatively, on postoperative day 1, and at discharge.

Block-related complications (hematoma, bleeding at the injection site, LAST), opioid-related side effects (itching, sedation, respiratory depression), time to first PCA demand, time to first mobilization, rescue analgesic requirements, and hospital length of stay will be recorded.

All data will be analyzed using SPSS software. Statistical tests will be selected based on data distribution, and a p-value < 0.05 will be considered statistically significant.

• Study Type: Observational
• Enrollment (Actual): 60

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Karabük, Turkey (Türkiye), 78200
    • Karabuk Training and Research Hospital, Department of Anesthesiology and Reanimation

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

Adult patients scheduled to undergo elective single-level lumbar discectomy at Karabuk Training and Research Hospital. Eligible participants will be evaluated preoperatively and enrolled prospectively according to predefined inclusion and exclusion criteria. No healthy volunteers are included.

Description

Inclusion Criteria:

• Adults aged 18 to 80 years
• Scheduled for elective single-level lumbar discectomy
• ASA physical status I-III
• Able to use patient-controlled analgesia (PCA)
• Able and willing to provide written informed consent

Exclusion Criteria:

• History of opioid use for longer than 4 weeks
• Presence of chronic pain before surgery (e.g., migraine, fibromyalgia)
• Alcohol or substance dependence
• Known allergy or hypersensitivity to local anesthetics or opioids
• Significant organ dysfunction (e.g., severe hepatic or renal disease)
• Revision or multilevel spine surgery
• Contraindications to regional anesthesia
• Severe psychiatric disorders limiting cooperation (e.g., psychosis, dementia)
• Pregnancy or breastfeeding
• Hematologic disorders

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Group QİPB; Patients receiving ultrasound-guided Quadro-Iliac Plane Block with 30 mL of 0.25% bupivacaine per side (total 60 mL) as part of routine postoperative analgesia after single-level lumbar discectomy.
Group WI; Patients receiving ultrasound-guided wound infiltration with 20 mL of 0.25% bupivacaine into the surgical field at the end of surgery as part of routine postoperative analgesia after single-level lumbar discectomy.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
24-hour cumulative opioid consumption	Total opioid consumption within the first 24 hours, including PCA-administered morphine and rescue analgesics converted to morphine milligram equivalents (MME).	postoperative day 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
12-hour cumulative opioid consumption	Total opioid consumption within the first 12 hours, including PCA-administered morphine and rescue analgesics converted to MME.	postoperative 12th hour
Block performance time	Total time (minutes) required to complete the QIPB procedure.	intraoperative period
Patient-reported quality of recovery (QoR-15 score)	Quality of recovery assessed using the validated 15-item QoR-15 questionnaire.	Postoperative day 1 and at postoperative day 2-4 day
Time to first PCA analgesic demand	Time at which the first analgesic is requested	Postoperative day 1
Number of patients requiring rescue analgesia	Number of patients who required rescue analgesia despite PCA use.	Postoperative day 1
Time to first mobilization	Time (hours) from the end of surgery to first assisted ambulation with a physiotherapist.	Postoperative day 2-4
Block-related complications	Incidence of complications such as bleeding, hematoma, or local anesthetic systemic toxicity (LAST).	Postoperative day 7
Opioid-related adverse effects	Presence of itching, sedation, fatigue, or respiratory depression related to opioid use.	Postoperative day 7
Length of hospital stay	Duration of hospitalization measured in hours or days.	Postoperative day 2-4
Postoperative pain scores (NRS at rest and activity)	Pain status at rest and while activity will be assessed by numeric rating scale (NRS) score at 0, 3, 6, 12, 18 and 24 hours after surgery. In addition, the time until the first analgesic requirement will be recorded. The NRS is an 11-point numeric scale that ranges from 0 to 10.	postoperative day 1
Postoperative nausea and vomiting incidence (PONV)	The severity of postoperative nausea and vomiting (PONV) will be assessed using a descriptive verbal rating scale at 0, 3, 6, 12, 18 and 24 hours after extubation. If a score of 3 or more, ondansetron 4 mg IV will be administered and will repeat after 8 hours if required (The PONV scale is 0 = no nausea; 1 = slight nausea; 2 = moderate nausea; 3 = vomiting once; and 4 = vomiting more than once).	Postoperative day 1

Collaborators and Investigators

• Sponsor: Elif Sarikaya Ozel
• Investigators: Principal Investigator: Elif Sarikaya Ozel, Karabuk Training and Research Hospital, Department of Anesthesiology

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2025
• Primary Completion (Actual): April 24, 2026
• Study Completion (Actual): May 1, 2026

Study Registration Dates

• First Submitted: November 15, 2025
• First Submitted That Met QC Criteria: November 15, 2025
• First Posted (Actual): November 20, 2025

Study Record Updates

• Last Update Posted (Actual): May 15, 2026
• Last Update Submitted That Met QC Criteria: May 13, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Wound Infiltration; Quadro-Iliac Plane Block; QIPB
• Other Study ID Numbers: QIPB-LD2026

Drug and device information, study documents

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