Improving Accuracy of Landmarks for Neuraxial Blocks in Pregnancy: The Sacral Anatomical Interspace Landmark (SAIL) Technique

Study Overview
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Brief Summary
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This study is a randomized clinical trial to evaluate the accuracy of the novel SAIL technique compared to the classic intercristal line technique in estimating the L4-L5 interspace for labor epidural or spinal anesthesia placement. The investigators hypothesize that the SAIL technique will be more accurate in successfully locating the L4-L5 interspace in pregnant women than the classic intercristal line technique.

Detailed Description
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The current standard technique aiming at identifying the L4-L5 intervertebral space as a reference point before performing a neuraxial block relies on the correct clinical estimation of the intercristal line. The classic intercristal line technique uses an imaginary line that intersects the iliac crests to determine a safe puncture level to access. In pregnant women, the classic technique fails to identify the safe puncture level 40 % of the time. The newly proposed Sacral Anatomical Interspace Landmark (SAIL) technique consists of using the sacral bone to determine a safe puncture level to access. Lumbar ultrasound will determine the accuracy of each clinical technique in identifying the L4-L5 interspace (target).

Official Title
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A Novel Method of Improving Accuracy of Anatomical Landmarks for Neuraxial Blocks in Pregnancy: The Sacral Anatomical Interspace Landmark (SAIL) Technique

Conditions
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Pregnancy Related

Intervention / Treatment
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* Other: Classic Intercristal Line Technique
* Other: Novel SAIL Technique


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Ultrasound-determined gestation age greater than or equal to 37 weeks Expressed interest or indication for epidural anesthesia Patients in the first stage of labor Exclusion Criteria: Patients perceived or indicating that she is unable to cooperate with positioning BMI greater than 45 kg/m2 Previous spine surgery or known spinal deformities Impaired decision making abilities non-English speaking

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Interventional Model Description: All patients will undergo estimation of the L4-L5 interspace using the classic and novel technique, followed by identification of the interspace using lumbar ultrasound.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: All Patients<br>Estimates of the location of the L4-L5 intervertebral space will be done by the classic intercristal line technique and novel SAIL technique. Each technique will be performed by different randomly assigned investigators. * Both techiques will be assessed on all patients | Other: Classic Intercristal Line Technique<br>* Researcher will use the classic technique to estimate the L4-L5 interspace. The classic technique begins by palpating both the right and left posterior iliac crests and following the imaginary line that intersects each (intercristal line) with the non-dominant hand to the spine where it is estimated to intersect the L4 spinous process or L4-L5 interspace. A marker pen will mark an X lateral to the estimation, opposite side from the estimation of the other technique.<br>* Other names: Standard of Care;Other: Novel SAIL Technique<br>* Researcher will use the novel technique to estimate the L4-L5 interspace. The SAIL technique begins by palpating the sacrum and the researcher sliding the non-dominant hand up the dorsal surface of the sacrum to the first interspace (L5-S1) and then up one more interspace to estimate the L4-L5 interspace. A marker pen will mark an X lateral to the estimation, opposite side from the estimation of the other technique.<br>* Other names: Experimental;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Accuracy, as measured by percentage of estimations that correctly match ultrasound determined interspace | Percentage of trials for the novel and classic technique respectively that the estimation correctly matches the L4-L5 interspace as determined by lumbar paramedian ultrasound will serve as a measure of accuracy | From enrollment to the end of data collection, approximately 15 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Anatomical Landmarks