Injection Pressure & Adductor Canal Block

University of Miami26 enrolled

Overview

This is a prospective, randomized, single-blinded human clinical trial that will examine how injection pressure influences the spread of a given volume of injectate in the adductor canal, during adductor canal nerve block. The study population will be patients undergoing elective anterior cruciate ligament repair in the distal lower extremity and receiving preoperative adductor canal nerve blocks for postoperative analgesia. They will be randomized into two groups of 25 patients each. The investigators speculate that high injection pressures (\>20 psi) will lead to greater spread of local anesthetic than low injection pressures (\<15 psi) during mid-thigh adductor canal nerve blocks. The primary endpoint is the spread of injectate, defined as the distance between the uppermost and lowermost limits of spread of local anesthetic as assessed by ultrasound. The secondary endpoints are the incidence of femoral and sciatic nerve blocks 30 minutes after block placement, amount of IV opioid administered intraoperatively and postoperatively, preoperative and postoperative pain (Numeric Rating Scale, 0-10), and postoperative physical therapy milestone achievement.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

SINGLE

Enrollment

Conditions

Orthopedic Disorders Injury of Anterior Cruciate Ligament

Interventions

High Pressure InjectionPROCEDURE

Adductor canal block performed at greater than 20 psi injection pressure

Low Pressure InjectionPROCEDURE

Adductor canal block performed at less than 15 psi injection pressure

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion criteria: 1. Planned general anesthetic. 2. American Society of Anesthesia classes I, II, or III. 3. Patients aged 18-65. 4. English-speaking patients. Exclusion criteria: 1. ASA classes IV and V. 2. Patients younger than 18 or older than 65. 3. Contraindication to regional anesthesia (coagulopathy, patient refusal). 4. Allergy to local anesthetic or other study medications. 5. BMI \> 35 kg/m2. 6. Chronic opioid use (daily or almost daily use for \> 3 months). 7. Active illicit drug use. 8. Additional surgical site other than the limb for adductor canal block. 9. Pregnancy. 10. Preexisting neuropathy in the operative limb. 11. Inability to communicate to investigators or hospital staff. 12. Inability to speak or understand English.

Locations (1)

University of Miami Hospital

Miami, Florida, United States

Outcomes

Primary Outcomes

Spread of Injectate

Our primary endpoint is the spread of injectate, defined as the distance between the uppermost and lowermost limits of spread of local anesthetic as assessed by ultrasound.

Time frame: Immediate post-procedure on day 1

Secondary Outcomes

Number of Events of Femoral Nerve Block 30 Minutes After Block Placement

Sensory testing will use a pinprick method in the femoral (anterior thigh), saphenous (medial calf proximal to the medial malleolus, top of the patella) and sciatic (posterolateral calf, plantar surface of the foot) nerve distributions; if patients are unable to feel the stimulus in the femoral nerve distribution, then an outcome of a femoral nerve block will be recorded.

Time frame: post-procedure and postoperative on day 1

Number of Events of Sciatic Nerve Block 30 Minutes After Block Placement

Sensory testing will use a pinprick method in the femoral (anterior thigh), saphenous (medial calf proximal to the medial malleolus, top of the patella) and sciatic (posterolateral calf, plantar surface of the foot) nerve distributions; if patients are unable to feel the stimulus in the sciatic nerve distribution, then an outcome of a sciatic nerve block will be recorded.

Time frame: post-procedure and postoperative on day 1

Postoperative Pain Scores (Numeric Rating Scale, 0-10)

Patients will rate their pain after surgery on a scale from 0-10, with 0 being no pain, and 10 being the worst pain of their life.

Time frame: postoperative on day 1

Postoperative Physical Therapy Milestone Achievement

The patient will be evaluated by physical therapy postoperatively using the Lower Extremity Function Scale (LEFS). The LEFS is a self-reporting measure (0-80 score range, where 0 is complete disability and 80 is fully functional).

Data from ClinicalTrials.gov

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