Ultrasound Guided Versus Land-mark Method for Spinal Anesthesia in Super Obesity Parturients

Comparison of Ultrasound and Anatomical Landmark Method in Spinal Anesthesia for Elective Cesarean Section in Super Obese Parturients With BMI ≥ 50 kg/m2. A Randomized Controlled Trial

This study will investigate whether an ultrasound-assisted technique is better than a classical land-mark technique to facilitate spinal anesthesia in the sitting position in super obese pregnant women with BMI ≥ 50 who will undergo elective cesarean section.

The primary objective of this study is the rate of successful dural puncture at the first attempt. It was assumed that ultrasound could facilitate neuraxial blockade in super obese (BMI ≥ 50 kg/m2), pregnant women, according to the Who classification, whose topographic anatomy is difficult.

Study Overview

Detailed Description

Spinal anesthesia is the most commonly used anesthesia method for elective cesarean deliveries. Anesthesiologists may struggle to determine the poorly palpable surface landmarks in super obese (BMI ≥ 50 kg/m2) pregnant women.

The manual palpation technique, preferred in neuraxial anesthesia, may be very difficult in super obese pregnant women due to difficulty identifying bone landmarks. Neuraxial ultrasound examination before spinal anesthesia may help spinal anesthesia performance and decrease the number of attempts in obese parturients.

This study will be a single-center, prospective, randomized, double-blinded trial in a university hospital. Patients scheduled for elective cesarean will be screened for enrollment in the study. The anesthetist administering spinal anesthesia and evaluating the data were blind to the distribution of patient groups. Ultrasonographic examinations were performed by a single investigator trained in this technique who performed more than 60 ultrasound-guided neuraxial blocks.

Study Type


Enrollment (Estimated)



  • 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 Contact

Study Locations

      • Karaman, Turkey, 70200
        • Karaman Training and Research Hospital

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

  • Adult

Accepts Healthy Volunteers



Inclusion Criteria:

  • Parturient who will receive selective cesarean delivery under spinal anesthesia
  • ASA 3 scheduled for elective sections
  • BMI≥50 kg/m2
  • Normal singleton pregnancy

    • 37 weeks of gestation

Exclusion Criteria:

  • Multiple gestations
  • Emergency C-section
  • Exist contraindications of spinal anesthesia
  • Local anesthetics allergy
  • BMI<50 kg/m2
  • History of lumbar spinal diseases and lumbar surgery
  • Parturient refusal

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Ultrasound method group
The ultrasound-assisted technique will be used for spinal anesthesia performance.

In the operating room, all of the patients will receive standard monitoring. Scans will be made in logiditunal parasagittal and transverse midline views with ultrasound. Needle entry sites in the L2-L3 and L3-L4 intervals will be determined as the intersection of the longiditunal and transverse lines.

When the spinal puncture operator is outside the room, Needle entry sites were marked for both groups.After skin marking, the pregnant woman will be asked to remain still and a subarachnoid puncture will be performed immediately. Spinal anesthesia will be administered with injection of intrathecal bupivacaine.

Experimental: Landmark method group
Land-mark assisted technique will be used for spinal anesthesia performance.
In the Landmark group, the injection site will be determined using the traditional method of palpating the posterior superior iliac spine.When the spinal puncture operator is outside the room, Needle entry sites were marked for both groups.After skin marking, the pregnant woman will be asked to remain still and a subarachnoid puncture will be performed immediately. Spinal anesthesia will be administered with injection of intrathecal bupivacaine.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The success rate of the first puncture
Time Frame: 30 minute
Success on a single-puncture attempt will be defined as reaching the subarachnoid space on the first insertion of the needle.
30 minute

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of skin punctures
Time Frame: 30 minute
Skin puncture is defined as any separate skin puncture attempt.
30 minute
Number of needle pass
Time Frame: 30 minute
Needle pass is defined as skin puncture plus number of redirection attempts
30 minute
The procedure duration time
Time Frame: 30 minute
The duration from initiation of location marking by palpation or ultrasound to obtaining free cerebrospinal fluid flow
30 minute
Time interval to determine needle insertion site
Time Frame: 30 minute
Time interval between the operator touches the parturient and the completion of the needle insertion point marking
30 minute
Time taken for spinal injection
Time Frame: 30 minute
The time interval between the needle insertion to visualization of cerebrospinal spinal fluid in the spinal needle.
30 minute
Number of puncture levels
Time Frame: 30 minute
Move to a second lumbar space after 3 needle insertion attempts
30 minute
Failure rate of spinal anesthesia
Time Frame: 120 minute
Number of parturients who need additional analgesic drug or conversion to general anesthesia
120 minute
Patient satisfaction The procedure duration
Time Frame: 120 minute
Patients rated their satisfaction as very satisfied, satisfied, or dissatisfied immediately after the procedure.
120 minute
incidence of complications during puncture
Time Frame: 120 minute
Incidence of radicular pain, paresthesia, and blood during spinal needle injection
120 minute
incidence of postoperative headache
Time Frame: 72 hours
12-72 hours following spinal anesthesia due to CSF leakage
72 hours
Incidence of hypotension
Time Frame: 2 hours
A systolic arterial pressure decrease of more than 25% from baseline or less than 90 mmHg
2 hours
dermatome level of sensory block
Time Frame: 10 minute
thoracic dermatome level of sensory block assessed by pinprick test
10 minute

Collaborators and Investigators

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


  • Principal Investigator: Ayşegül Bilge, MD, Karaman TRH

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 (Estimated)

May 7, 2024

Primary Completion (Estimated)

October 1, 2024

Study Completion (Estimated)

October 2, 2024

Study Registration Dates

First Submitted

April 4, 2024

First Submitted That Met QC Criteria

May 8, 2024

First Posted (Actual)

May 13, 2024

Study Record Updates

Last Update Posted (Actual)

May 13, 2024

Last Update Submitted That Met QC Criteria

May 8, 2024

Last Verified

April 1, 2024

More Information

Terms related to this study

Other Study ID Numbers

  • 11-2022/03

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product


Studies a U.S. FDA-regulated device product


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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