'Mapping the area of anaesthesia following an ultrasound guided arm nerve block in health volunteers'

Phase 4

Completed

• Conditions: Sensory loss to pain; Anaesthesiology - Anaesthetics

• Registration Number: ACTRN12618000891224
• Lead Sponsor: Concord Repatriation General Hospital

Brief Summary

Background and Objectives: The aim of the study was to investigate a novel ultrasound-guided posterior antebrachial cutaneous nerve (PABCN) block based on visualising the nerve within the fat-filled flat tunnel (FFFT) and describe the area of cutaneous sensory loss. Methods: Twelve healthy volunteers were included in the study. The PABCN was identified within the FFFT in the upper arm using high frequency ultrasound. The nerve was blocked using an in-plane needle guidance technique with 1ml 2% lignocaine. Sensory loss to pinprick was evaluated 15 minutes after performing the block and the cutaneous sensory block area (CSBA) mapped. Results: Ultrasound visualization of the PABCN in the FFFT was possible in all volunteers. The median distance of the PABCN to the lateral epicondyle of the elbow was 67.5 (range, 54-105) mm. Sensory loss to pinprick extended from the posterior aspect of the distal upper arm and posterior forearm to the wrist. The median CSBA was 103 (range, 61-341) cm2. Two volunteers had sensory block over the anterior forearm of 29 and 10 cm2 respectively. This amounted to 11% and 4.5% of the total CSBA. One volunteer had a sensory block over the dorsum of the hand of 39cm2 (15% of the total CSBA). Conclusions: The results of this study indicate that the FFFT can be a useful sono-anatomical landmark in identifying the PABCN and may serve as a target for injection. Although sensory block is predominantly confined to the posterior distal arm and forearm, inter-individual variability in the area and distribution was observed. Sensory block in the anterior forearm and dorsum of the hand can occur.

Detailed Description

Not available

Study Timeline

• Results First Posted: 1900-01-01
• Study Start: 2018-05-28
• Study Completion: 2018-12-30
• Last Update Posted: 16 November 2020

Recruitment & Eligibility

• Status: Completed
• Sex: All
• Target Recruitment: 12

Inclusion Criteria

Healthy volunteers, male and female, aged 18 to 65 years old, BMI 18-35 kg/m2.

Exclusion Criteria

Known allergy to local anaesthetic drugs; injury, deformity or previous surgery to the right arm or PABCN; pain or pre-exiting neurological deficit of the right arm; identifying features on the arm such as tattoos, moles, scars or birthmarks.

Study & Design

• Study Type: Interventional
• Study Design: Not specified