Midline vs. Paramedian Approaches for US-assisted Spinal Anesthesia

Study Overview
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Brief Summary
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Ultrasound has emerged as an useful tool for neuraxial blockade. The aim of this study is to compare the efficacy and safety between the midline approach and paramedian approach for ultrasound-assisted spinal anesthesia in adult patients.

Official Title
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Midline Versus Paramedian Approaches for Ultrasound-assisted Spinal Anesthesia: a Randomized Controlled Trial

Conditions
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Anesthesia, Spinal, Ultrasonography

Intervention / Treatment
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* Procedure: ultrasound-assisted midline approach
* Procedure: ultrasound-assisted paramedian approach


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients scheduled to undergoing elective orthopedic surgery under spinal anesthesia, with ASA physical status classification I, II, III Exclusion Criteria: Patients with contraindication to spinal anesthesia (coagulopathy, local infection, allergy to local anesthetic) Patients with morbid cardiac diseases Pregnancy Patients with previous history of lumbar spinal surgery Patients with anatomical abnormality of lumbar spine

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Midline group<br>Preprocedural ultrasound-assisted midline approach of spinal anesthesia will be performed. 0.5% heavy bupivacaine will be injected to intrathecal space for spinal anesthesia. | Procedure: ultrasound-assisted midline approach<br>* A preprocedural ultrasound scanning will be done, and skin marking will be made. The needle entry point and insertion angle will be determined based on ultrasound scanning. Spinal anesthesia will be performed via midline approach.<br>|
| Active Comparator: Paramedian group<br>Preprocedural ultrasound-assisted paramedian approach of spinal anesthesia will be performed. 0.5% heavy bupivacaine will be injected to intrathecal space for spinal anesthesia. | Procedure: ultrasound-assisted paramedian approach<br>* A preprocedural ultrasound scanning will be done, and skin marking will be made. The needle entry point and insertion angle will be determined based on ultrasound scanning. Spinal anesthesia will be performed via paramedian approach.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| the number of needle passes | the number of forward advancements of the spinal needle in a given interspinous space, i.e., withdrawal and redirection of spinal needle without exiting the skin | Intraoperative (from the first insertion of needle to patient's skin, until the completion of spinal anesthetic injection) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of spinal needle insertion attempts | the number of times the spinal needle was withdrawn from the skin and reinserted | Intraoperative (from the first insertion of needle to patient's skin, until the completion of spinal anesthetic injection) | 
| Time for identifying landmarks | time from placement of the ultrasound probe on the skin to the completion of markings. | intraoperative (time taken for establish the landmark, from start of US scanning to completion of scanning | 
| Time taken for performing spinal anesthetic | time from needle insertion to the completion of injection | Intraoperative (from insertion of the needle to the completion of injection) | 
| dermatome level of sensory block | thoracic dermatome level of sensory block assessed by loss of cold sensation tested with 2% chlorhexidine swab | 20 minutes after the completion of spinal anesthetic injection | 
| Incidence of radicular pain, paraesthesia, and blood tapping in the spinal needle | Incidence of radicular pain, paraesthesia, and blood tapping in the spinal needle during the spinal anesthesia procedure | Intraoperative (from the first insertion of needle, until the completion of spinal anesthetic injection) | 
| Periprocedural pain | 11-point verbal rating scale (0=no pain, 10=most pain imaginable) | Patients will be asked immediately after the completion of spinal anesthesia | 
| Periprocedural discomfort score | 11-point verbal rating scale (0=no discomfort, 10=most discomfort imaginable) | Patients will be asked immediately after the completion of spinal anesthesia | 
| Patient satisfaction score of spinal anesthesia procedure | 11-point verbal rating scale (0=very unsatisfied, 10=very satisfied) | Patients will be asked immediately after the completion of spinal anesthesia |