• Olusola Allen Akinmola National Postgrduate Medical College of Nigeria (NPMCN)


Surgical procedures on the lower arm are quite suited for brachial plexus anaesthesia. The
trend in my centre, however, has been to administer general anaesthesia for operations on and
below the elbow. The axillary brachial plexus block avoids the problems of endotracheal
intubation and other general anaeathesia-related adverse effects and provides improved early
postoperative pain relief. The transarterial technique for axillary plexus block enables local
anaesthetic to be deposited immediately adjacent to the axillary artery and in close proximity to
the individual nerves of the brachial plexus within the axillary sheath. It has been proven to be
efficacious and safe. In a resource-poor setting like ours, where advanced technical equipment like
ultrasound machine and nerve stimulator are lacking, there is a need to have an effective and safe
technique of axillary brachial plexus block for lower arm operations. Hence, the evaluation of two
different techniques of transarterial axillary brachial plexus blocks.
This is a prospective, randomized, double blind comparative trial, which was approved by
the Health Research Ethics Committee of National Hospital, Abuja. American Society of
Anaesthesiologists physical status classes I and II subjects aged between 18 and 60 years drawn
from both sexes scheduled for elective procedures on the elbow, forearm, wrist and the hand
participated in the study. The patients were randomly allocated to receive a single (posterior)
injection, group A (n=35) or double (posterior and anterior) injections, group B (n=35) of 40 mL
pre-mixed solution containing 20 mL 1% lidocaine with adrenaline 1: 200,000 and 20 mL 0.25%
plain bupivacaine into the axillary sheath. Patients in the posterior group (group A) received the
entire solution posterior to the axillary artery while those in the double group (group B) received
20 mL each of same local anaesthetic mixture, posterior and anterior to the axillary artery. A
multiparameter patient monitor (Mindray BeneView T5) was attached and baseline vital signs
were measured. A venous access was established in each patient and an intravenous infusion of
lactated Ringers solution was commenced, and, transarterial axillary brachial plexus block was
established. In all the patients, the success rate, performance time, time to block readiness for
surgery, total anaesthetic time, need for rescue analgesics, and occurrence of adverse events were
A total of 70 patients were randomized equally into group A and group B. The socio
demographic characteristics and ASA status of patients in both groups were similar. The groups
did not differ significantly in success rate (group B 91% versus group A 88%, p=0.434). Time for
block performance was prolonged (9.20 ± 2.56 minutes versus 8.06 ± 1.83 minutes, p=0.035) and
block readiness for surgery was shortened (23.43 ± 4.82 minutes versus 26.18 ± 4.93 minutes,
p=0.022) in group B but total anaesthesia-related time was similar in the two groups (p=0.204).
The onset of sensory block was hastened in group B (double injection) in the median nerve
(p=0.042), musculocutaneous nerve (p=0.019), medial cutaneous nerve of the forearm (p=0.001)
and the medial cutaneous nerve of the arm (p=0.004). Also, the duration of sensory analgesia
(375.00 ± 62.84 minutes versus 329.03 ± 51.08 minutes, p=0.002) and motor block (346.88 ±
45.04 minutes versus 319.35 ± 47.46 minutes, p=0.021) was longer in group B (double injection
technique) compared to group A (single injection). The occurrence of tourniquet pain (p=0.232),
accidental paraesthesia (p=0.274), intra-operative opioid use (p=0.403), and conversion to general
anaesthesia (p=0.690) was similar in both groups. There were no significant adverse events and
patients in both groups expressed high level of satisfaction with the technique of anaesthesia.
The study showed that the single and double injection transarterial techniques of axillary
plexus block with 40 mL 1% lidocaine in 1: 200,000 adrenaline and 0.25% plain bupivacaine
mixture ensured similar clinical success rate with minimal side effects. The double injection
technique results showed longer duration of sensory analgesia, thus, may be a more favourable
technique for surgery on and below the elbow.