"Ultrasound vs. Landmark Technique for Spinal Anesthesia in Obese Women Undergoing Cesarean Section"

May 20, 2026 updated by: Kazi Mahzabin Arin, Bangladesh Medical University

Evaluation of Ultrasound Assisted Localisation of the Intervertebral Space Versus the Traditional Landmark Technique During Subarachnoid Block for Caesarean Section in Obese Parturient

The goal of this clinical trial is to evaluate whether the ultrasound-assisted technique improves the accuracy and safety of spinal anesthesia compared to the traditional landmark technique in obese women undergoing a cesarean section. The main questions it aims to answer are:

Does the ultrasound-assisted technique reduce the number of needle attempts required for successful spinal anesthesia? Does the ultrasound-assisted technique decrease the incidence of post-dural puncture headache (PDPH) and chronic low back pain at the needle insertion site? Does the ultrasound-assisted technique reduce procedure time compared to the landmark technique?

Participants will:

Receive spinal anesthesia using either the ultrasound-assisted technique or the traditional landmark technique for cesarean section.

Be monitored for the number of needle attempts, procedure time, and any post-operative complications such as PDPH or low back pain.

Follow up for three months after the procedure to assess any long-term effects, including chronic low back pain and quality of life.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This clinical trial is designed to compare two techniques for performing subarachnoid block (SAB) in obese women undergoing elective cesarean sections. The study aims to evaluate the effectiveness and safety of ultrasound-assisted spinal anesthesia versus the traditional landmark-guided technique. Both techniques are commonly used for regional anesthesia, but the effectiveness of ultrasound assistance in improving procedural accuracy, reducing complications, and enhancing the overall success rate in obese parturient has not been sufficiently studied.

Study Design

This is a randomized controlled trial conducted at the Obstetric Operating Theatre of Bangladesh Medical University (BMU). Participants will be randomly assigned to one of two groups: Group A (landmark technique) and Group B (ultrasound-assisted technique). The study will evaluate the following:

Primary Objective:

To assess the number of needle attempts required for successful subarachnoid block in both groups.

Secondary Objectives:

To evaluate the procedure time, incidence of post-dural puncture headache (PDPH), chronic low back pain at the needle insertion site, and quality of life related to pain.

Interventions

Both groups will receive the same local anesthetic agents for the SAB: 0.5% hyperbaric bupivacaine with 25 μg fentanyl. The techniques will differ in how the intervertebral space is located.

Group A (Landmark Technique): In this technique, the L3-L4 or L4-L5 intervertebral spaces will be identified using the traditional landmark method. The anesthesiologist will palpate the iliac crests to find Tuffier's line and will estimate the intervertebral space based on these bony landmarks.

Group B (Ultrasound-Assisted Technique): In this group, ultrasound guidance will be used to locate the intervertebral space. A low-frequency (2-5 MHz) curvilinear probe will be employed to visualize the lumbar spine. The procedure will include scanning the area to identify the midline, the interlaminar spaces, and the depth of the epidural and spinal spaces, ensuring that the correct intervertebral level is identified before needle insertion.

Randomization

Participants will be randomly assigned to one of the two intervention groups using Block randomization schedule. This will ensure that both groups are comparable at baseline and that the results are unbiased.

Procedure

Before the procedure, participants will undergo routine preoperative assessment, including fasting for 6 hours, intravenous line establishment, and monitoring. They will be positioned in a sitting position with a pillow for lumbar flexion. After preparing the skin with aseptic techniques, the spinal needle will be inserted according to the assigned technique.

In Group A, after identifying the L3-L4 or L4-L5 intervertebral space using the landmark technique, the anesthesiologist will administer the Subarachnoid Block (SAB). In Group B, ultrasound will be used to precisely identify the lumbar intervertebral spaces before needle insertion.

Follow-Up

Participants will be monitored for immediate postoperative complications, including Postdural puncture headache (PDPH), and will be assessed for chronic low back pain at the needle insertion after 3 months over phone. Additionally, the quality of life related to low back pain will be evaluated via phone interviews.

Expected Outcomes

The primary hypothesis is that the ultrasound-assisted technique will result in fewer needle attempts and a more accurate identification of the intervertebral space compared to the traditional landmark technique. Additionally, investigators expect to find that ultrasound assistance reduces the incidence of Postdural puncture headache (PDPH) and chronic low back pain, thereby improving the patient's overall quality of life postoperatively.

This trial will provide valuable insights into the effectiveness of ultrasound in improving the safety and accuracy of Subarachnoid Block (SAB) in obese parturient, potentially changing the standard of care in obstetric anesthesia for this patient population.

Study Type

Interventional

Enrollment (Actual)

60

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Bangladesh
      • Dhaka, Bangladesh, 1000
        • Bangladesh Medical University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Elective caesarean section
  • ASA physical status: Ⅱ
  • Obese parturient (BMI ≥ 30.1 kg/m²)

Exclusion Criteria:

  • Allergic to local anaesthetic (0.5% Bupivacaine hydrochloride with 8% Dextrose and 2 % Lidocaine hydrochloride USP)
  • Preexisting neurological deficit by clinical examination
  • Any contraindication to SAB
  • History of scoliosis or spinal instrumentation
  • Allergy to ultrasound transmission gel

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Group A: Landmark-Guided Spinal Anesthesia
In this arm, participants will receive subarachnoid block using the traditional landmark technique for spinal anesthesia. The L3-L4 or L4-L5 intervertebral space will be identified by palpating the iliac crests to locate Tuffier's line, and the spinal needle will be inserted based on these bony landmarks. The anesthetic agents administered will be 0.5% hyperbaric bupivacaine (10 mg) and 25 μg fentanyl (0.5 mL). The procedure will be performed by experienced anesthesiologists.
Procedure: Landmark-Guided Spinal Anesthesia
This intervention involves the use of traditional anatomical landmarks to locate the correct intervertebral space for performing subarachnoid block (SAB). The anesthesiologist identifies the L3-L4 or L4-L5 intervertebral space by palpating the iliac crests and using Tuffier's line as a reference. A 25G Quincke needle is used for SAB, and 0.5% hyperbaric bupivacaine with 25 μg fentanyl is administered. This technique is the standard approach used in many clinical settings for spinal anesthesia.
Experimental: Group B: Ultrasound-Assisted Spinal Anesthesia
In this arm, participants will receive subarachnoid block using the ultrasound-assisted technique. A low-frequency (2-5 MHz) curvilinear probe will be used to visualize the lumbar spine and identify the intervertebral space. The correct intervertebral space (L3-L4 or L4-L5) will be identified using real-time ultrasound imaging. The anesthetic agents administered will be 0.5% hyperbaric bupivacaine (10 mg) and 25 μg fentanyl (0.5 mL). This procedure will also be performed by experienced anesthesiologists with expertise in neuraxial ultrasound.
Procedure: Ultrasound-Assisted Spinal Anesthesia
This intervention utilizes ultrasound guidance to identify the correct intervertebral space for performing subarachnoid block (SAB). A low-frequency (2-5 MHz) curvilinear ultrasound probe is used to visualize the lumbar spine in real-time, ensuring precise identification of the L3-L4 or L4-L5 intervertebral space. The anesthesiologist places the needle based on ultrasound images that show the anatomical structures, such as the spinous processes and interlaminar spaces. The same anesthetic agents (0.5% hyperbaric bupivacaine and 25 μg fentanyl) are administered through a 25G Quincke needle for SAB.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of Needle Attempts for Successful Subarachnoid Block
Time Frame: During the procedure, until successful spinal needle placement
his is the key measure in your study, as it directly assesses the effectiveness of the two anesthesia techniques (ultrasound-assisted vs. landmark-guided) in achieving successful spinal anesthesia. Fewer needle attempts would indicate a higher success rate and a more efficient technique, making it the most critical outcome for evaluating the interventions.
During the procedure, until successful spinal needle placement

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Needle Insertion Site Accuracy in landmark technique group
Time Frame: Immediately after transferring the participants in the recovery room
This measure evaluates whether the correct intervertebral space was identified and the needle was inserted at the intended location. Accuracy will be assessed using ultrasound imaging in the recovery room to verify the spinal leve
Immediately after transferring the participants in the recovery room
Procedure Duration in minutes
Time Frame: During procedure
This outcome will assess the time taken to perform the spinal anesthesia procedure from the beginning of patient positioning for spinal anaesthesia to the successful Spinal Needle insertion.
During procedure
Incidence of Post-Dural Puncture Headache (PDPH)
Time Frame: Postoperative period (up to 72 hours)
The incidence of PDPH will be recorded in the immediate postoperative period. Participants will be monitored for symptoms such as headache, nausea, and neck stiffness, which are common after dural puncture.
Postoperative period (up to 72 hours)
Chronic Low Back Pain at Needle Insertion Site
Time Frame: 3 months post-procedure
Chronic low back pain at the needle insertion site will be evaluated via phone follow-up using the Numerical Rating Scale (NRS) to assess pain intensity. The impact on daily activities, including work, sleep disturbances, and mobility, will also be documented
3 months post-procedure
Impact of Chronic Low Back Pain on Quality of Life
Time Frame: 3 months post-procedure

Quality of life is assessed using the 12-Item Short Form Health Survey (SF-12), a validated, widely used questionnaire measuring health-related quality of life across two domains:

Physical Component Summary (PCS): captures physical functioning, bodily pain, and general physical health.

Mental Component Summary (MCS): captures emotional well-being, social functioning, vitality, and mental health.

Responses are collected via phone interview by trained study staff. Data are coded according to Short-Form-12 (SF-12) guidelines and aggregated into summary scores.

Score Range: 0-100, with higher scores indicating better quality of life (less limitation or distress).
3 months post-procedure

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Bangladesh Medical University

Investigators

  • Study Director: AKM Akhtaruzzaman, MD, Bangladesh Medical University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 1, 2025

Primary Completion (Actual)

August 30, 2025

Study Completion (Actual)

November 30, 2025

Study Registration Dates

First Submitted

May 8, 2026

First Submitted That Met QC Criteria

May 15, 2026

First Posted (Actual)

May 22, 2026

Study Record Updates

Last Update Posted (Actual)

May 22, 2026

Last Update Submitted That Met QC Criteria

May 20, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 5294

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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