Ultrasound-guided Nerve Blocks for the Sciatic and Saphenous Nerves: Characteristics of the Single Penetration Dual Injection (SPEDI) Technique

Bispebjerg Hospital60 enrolled

Overview

Background and aims: Ultrasound-guided (USG) nerve blocks of the sciatic nerve (popliteal level = PL) and the saphenous nerve (mid-femoral level = MFL) provides analgesia following leg surgery. Traditionally two separate injections are performed. The aim was to describe a novel, faster USG block combination requiring only one skin penetration to block the sciatic and saphenous nerves; i.e. the SPEDI block = Single PEnetration Dual Injection. Methods: A randomized, controlled and double-blinded trial. Following ethics committee approval 60 patients will be randomized to the administration of an USG SPEDI block compared to two separate USG blocks of the saphenous (MFL) and sciatic (PL) nerves. Blocks will be performed after induction of general anaesthesia. Outcome measures will be performance time (primary outcome measure), Post-Anaesthesia Care Unit pain scores (VAS scores 0-10), block difficulty level (easy, middle, difficult), opioid consumption (in the PACU), serum-ropivacaine pharmacokinetics (blood sample 0-180 minutes). Both block combinations will be evaluated by MR imaging (MRI). Hypothesis: The USG SPEDI block combination is expected to be performed significantly faster without moving the leg, and achieve successful perioperative pain management. The SPEDI block may find important use in the emergency setting.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Enrollment

Conditions

Lower Leg Surgery, e.g. Ankle Fractures

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * lower leg surgery * American Society of Anesthesiologist (ASA) score I-III * Can cooperate in the study * Speaks and understand the Danish language * General anesthesia Exclusion Criteria: * Intake of oral morphine above 40 mg per day * Know allergy to ropivacaine * Abuse of alcohol or other substance abuse * Neuropathy * Pregnant * Nerve block contraindicated

Outcomes

Primary Outcomes

Performance time (seconds and minutes). Time measurement from the time the ultrasound transducer is placed on the skin and until the needle is taken out of the body.

The time measurement is done with a normal clock - measuring seconds and minutes.

Time frame: The measurement (seconds and minutes) will take place in the operating room. This will normally be within a time frame of 1 minute to 10 minutes.

Secondary Outcomes

Pain score (VAS score 0-10).

Time frame: When the patient are evaluated in the recovery unit upon arrival and when the patient is discharged from the recovery unit. This means from time 0 hours (arrival in the PACU) and normally until 2 hours after arrival in the PACU.

Sensory dermatome testing.

Sensory dermatome testing is done with cold ethanol on skin test. All dermatomes on the leg and foot are tested, and there is a comparison of the outcome between the operated leg and the not-operated leg.

Time frame: Normally until 2 hours postoperatively.