Real-time Ultrasound-guided Spinal Anesthesia:A Feasibility Study

Study Overview
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Brief Summary
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The traditional landmarks to locate the injection site and orientation of the spinal needle for spinal anesthesia are based on palpation of surface bony landmarks. However the actual injection target into the CSF is located at an unknown depth inside the patients 3 dimensional spinal anatomy which can itself vary in its orientation relative to these surface markers.Also bony surface markers may not be palpable in some patients or the patient may have altered spinal alignment. Thus an already blind procedure can become even more misguided involving multiple trial and error needle insertions. On the other hand ultrasound allows visualisation of deep target structures which are impalpable, it allows assessment of spinal alignment and thus directs the orientation of the seeking needle more accurately. Performing US in real-time during needle insertion gives continuous feedback about the correct needle approach path which should reduce the number of blind needle passes.

Official Title
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Feasibility Study of the Use of Real-time Ultrasound Guidance to Administer Spinal Anesthesia

Conditions
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Ultrasound Spinal Anesthesia

Intervention / Treatment
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* Procedure: Real-time ultrasound guided spinal anesthesia


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Consenting patients of at least 18 years of age undergoing spinal anesthesia for elective lower limb surgery Exclusion Criteria (are as for Spinal anesthesia generally) Patient refusal Sepsis or local infection at the site of injection Hypovolemia Coagulopathy (INR ≥1.5, Platelets < 75X 109 /L, anticoagulant therapy) Indeterminate neurologic disease Increased intracranial pressure Local anesthetic allergy Infection distinct from the site of injection Unknown duration of surgery

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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients requiring spinal anesthesia for lower limb surgery<br>Patients of at least 18 years of age undergoing spinal anesthesia for elective lower limb surgery will be recruited. Therefore inclusion and exclusion criteria are the same as for traditionally administered spinal anesthesia as below. Additionally we will exclude those patients who are incapable of providing fully informed consent, patients who are currently enrolled in other studies and patients with communication difficulties | Procedure: Real-time ultrasound guided spinal anesthesia<br>* The neuraxial US scan will be performed with the patient in the sitting or lateral position with the hip and knees slightly flexed using full aseptic technique. The spinal needle will be inserted in real-time under direct ultrasound guidance to administer the spinal anesthetic.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of ventral passes of the spinal needle into the patient |  | Assessed at time of spinal anesthetic injection (baseline) | 
| Rate of successful performance of real-time ultrasound guided spinal needle insertion |  | Assessed at time of spinal anesthetic injection (baseline) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time for the procedure from first needle contact to the skin to injection of the medication into the spinal canal |  | Assessed at time of spinal anesthetic injection (baseline) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Spinal anesthesia, ultrasound, real-time