Ultrasound-assisted Spinal Anaesthesia in Patients With Difficult Anatomical Landmarks

Study Overview
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Brief Summary
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Spinal anesthesia is the technique of choice in patients undergoing total joint arthroplasty at Toronto Western Hospital (UHN). The most significant predictor of the ease of performance of spinal anesthesia is the quality of palpable surface landmarks (the spinous processes of the lumbar vertebrae). These surface landmarks may be absent, indistinct or distorted in many of the patients presenting for total joint arthroplasty. This is because of obesity, previous spinal surgery, scoliosis and degenerative changes of aging. The investigators have shown in a previous study that a pre-procedural ultrasound scan of the spine can reliably identify an appropriate site for needle insertion in spinal anesthesia, and that this results in a high success rate on the first needle insertion attempt (84% vs 61-64% in published studies). The investigators therefore believe that this ultrasound-assisted technique of spinal anesthesia is extremely useful, especially in patients with poor-quality surface landmarks. However there are no published randomized controlled trials to date that compare the efficacy of the ultrasound-assisted technique with the traditional surface landmark-guided technique of spinal anesthesia.

Official Title
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A Randomised Controlled Trial of Ultrasound-assisted Spinal Anaesthesia in Patients With Difficult Anatomical Landmarks.

Conditions
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Spinal Anesthesia

Intervention / Treatment
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* Procedure: Ultrasound guidance
* Procedure: Manual palpation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Planned spinal anesthesia for elective lower limb surgery; and one or more of the following: Body mass index ≥ 35 kgm-2 Scoliosis or other spinal deformity Poorly palpable or impalpable spinous processes Exclusion Criteria: Patient refusal Contra-indications to regional anesthesia Known allergy to local anesthetics Bleeding diathesis Inability to provide informed consent

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Ultrasound<br>Use of ultrasound to identify vertebral interspaces for needle insertion. | Procedure: Ultrasound guidance<br>* ultrasound imaging<br>|
| Active Comparator: Palpation<br>Use of manual palpation to identify vertebral landmarks and vertebral interspaces for needle insertion. | Procedure: Manual palpation<br>* Manual Palpation of vertebra<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The success rate of dural puncture on the first needle insertion attempt. |  | within 2 hours prior to surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| number of needle insertions/re-directions; performance time; Pain score; Patient satisfaction; quality of ultrasound image; Correlation between palpation and ultrasound; Correlation between ultrasound and measured depth to i.t. space |  | within 2 hours prior to surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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spinal anesthesia, ultrasound, palpation, knee, hip, surgery, intervertebral space