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Intercostobrachial nerve blockade using high resolution ultrasound:
A Volunteer study
A. Thallaj 1, M.Al Harbi 2 , T. Alzahrani 3, S. El-Tallawy 4, A. Alsaif 5,
and M. Alnajjar 6
1.
2.
3.
4.
5.
6.
Ahmed Thallaj [email protected]
Mohammed Khulaif Al Harbi [email protected]
Tariq Al Zahrani [email protected]
Salah El Tallawy [email protected]
Abdulaziz Al Saif [email protected]
Mohanad Al Najjar [email protected]
1,3,6 Associate Professor, Department of Anesthesia, King Saud University
College Of Medicine
2 Assistant professor,King Saud Bin Abdulaziz University for Health ScienceRiyadh
5 Associated Professor, Department of Surgery,
6 Consultant , Department of Anesthesia,
College of Medicine, King Saud University, Riyadh, KSA
Correspondent author:
Mohammed Al Harbi MD,FRCPC
E-mail: [email protected]
Riyadh 11472, P.O. Box 7805
Anesthesia Department,King Abdulaziz Medical City
Riyadh, KSA.
Short running title:
Ultrasound investigation of the ICBN
Conflict of interest statements: None
1
ABSTRACT
Background: ICBN is a sensory nerve arises mainly from T2, and is not anesthetized by
brachial plexus block. Clinically, ICBN blockade is necessary for any surgical procedure where
the surgical incision extends into the axilla or into the upper medial arm.
Purpose: Our objective was to test the hypothesis that identification and blockade of the ICBN
can be achieved under US guidance. Small volume of local anesthetic would be effective.
Design: A prospective volunteer clinical trial.
Patients: 28 adult male volunteers.
Methods: 6-15 Mhz linear US probe was positioned at the apex of the axilla and scan the
axillary vein in short axis view.When the axillary vein reachs the lateral border of the pectoralis
major muscle, the ICBN apprears superior and posterior to the vein. Blockade of the ICBN was
performed with a 22-G 50 mm facet tip needle in an in-plain technique. 1 ml Lidocaine 2% was
injected under direct US control. A sensory map of the blocked area was developed relative to
medial aspect of the humeral head.
Results: Ultrasound visualization of the nerve superficial and posterior to the axillary vein at a
distance 1.48+0.17 (mean + SD) was possible in all cases. The ICBN appears as hyper-echoic
oval shaped structure. The nerve diameter was 2.3+0.28 mm and depth was 9+ 0.28 mm. The
sensory blocked area relative to the medial aspect of the humeral head was as follows: 6.3+ 1.6
cm anteriorly, 6.2+2.9 cm posteriorly, 9.4+2.9 cm proximally and 9.2+4.4 cm distally. Blockade
of the ICBN with 1 ml of local anesthetic through an "in plane technique" was successful in all
cases.
Conclusion: The study describes the sonographic anatomical details of the ICBN and its sensory
distribution that helps in successfully performing selective US guided blockade of this nerve.
Abreviation: ICBN: Intercostobrachial nerve
US: Ultrasound
2
Introduction
The intercostobrachial nerve (ICBN) is a pure sensory nerve arises primarily from the
second intercostal nerve (T2) with occasional contribution from T1 or T3. Therefore,
ICBN is not a component of the brachial plexus and is not anesthetized by brachial
plexus block. In its extra-thoracic course, the ICBN runs parallel to the axillary vein at a
distance of around 1.5 cm in a vertical dimension and provides sensory supply to the
axilla, upper medial arm and a small area at the upper lateral chest (1, 2). Clinically,
ICBN block is necessary for any surgical procedure where the surgical incision extends
into the axilla or into the upper medial arm. ICBN blockade may help reducing noxious
stimulation associated with the use of tourniquet during upper limb surgery (3). Selective
ICBN
blockade
technique
has
not
been
described
in
the
literature,
but
rather
subcutaneous ring infiltration to block the nerve endings (4 ). US have proven to be a
valuable tool for direct identification of small nerves such as medial antebrachial
cutaneous nerve of the forearm (5) . Consequently, the ICBN can also be identified by
US. We designed a prospective, volunteer study to describe a technique for US
visualization and guided blockade of ICBN followed by mapping its sensory skin supply.
Methods
After the institution’s IRB approval; an informed written consent was obtained
from all volunteers prior to their recruitment. A total number of thirty nine hospital staff
were interviewed, Eleven staff were excluded according to the exclusion criteria of the
study.
Inclusion criteria:
-
Adult male patients.
-
Body mass index < 30.
-
Agreed and consented for US examination with subsequent blockade of the ICBN.
Exclusion criteria:
-
History of allergy to Local Anesthetics.
-
Previous surgery at or near the site of study.
-
Pre-existing neurological disease.
-
Patients on anticoagulant therapy or history of coagulopathy.
3
The study included twenty eight volunteers at King Khalid University hospital from
November 2012 till September 2013 . All the volunteers underwent US identification and
subsequent blockade of the ICBN.
On the day of the study, the volunteers were admitted to the Block room and an IV
line was established. Each volunteer was placed on supine position with his arm
abducted and elevated above head level. An US scan was performed with 6-15 MHz ,
50mm linear probe (Sonosite M-Turbo, Sonosite Inc, Bothhell. WA, USA). The probe
positioned at the apex of the axillary fossa to scan the axillary vein in short axis view,
the depth on US screen was set to 2.7 cm, the US probe slide proximally towards the
base of the axilla, at a distance of approximately 6 cm proximal to the medial aspect of
the humeral head (Fig 1), the axillary vein becomes deeper on US screen and inferior to
the postero-lateral border of the Pectoralis Major muscle (Fig 2). The probe is then
positioned slightly oblique, and the depth on US screen was reduced to 1.5 cm for clear
identification of the nerve in cross section view. At this point, the ICBN appeared as
hyper-echoic oval structure surrounded by fascial split superior and posterior to the
axillary vein, midway on an imaginary line crossing the borders of the Pectoralis Major
and Latissimus Dorsi muscles as illustrated in (Figure 3). Releasing the pressure applied
on US probe frequently reveals a small hypoechoic rounded collapsible vessels visualized
anterior or posterior to the nerve. The pressure on the probe is reapplied again. The area
of interest was zoomed to measure the horizontal nerve diameter and its depth in
addition to the distance of the nerve to the axillary vein and nerve to lateral border of
the Pectoralis Major muscle. The nerve to medial aspect of the humeral head distance
was measured using measuring tape. Subsequently, the nerve was traced toward its distal
end as it became more superficial and divided into two or three smaller branches.
After surgical disinfection of the axillary area and sterile preparation of the US
probe, blockade of the ICBN is performed with a prefilled 22-Gauge ,50 mm facet tip
needle (Pajunk, Geisingen, Germany) in an in-plain technique. After a negative aspiration
an one ml of Lidocaine 2% was injected under direct US visualization. All the blocks
were performed by the same anesthesiologist.
4
Sensory blockade was assessed by another investigator every 2 minutes for the
first ten minutes. The onset of the block was determined by lose of cold sensation at
the skin of the axillary area.
Blocked area was tested to pinprick and compared to contra lateral side. Sensory block
was graded on a scale from (0- 10); with “0” representing complete absence of sensation
and “10” represents no difference compared to the other side. Finally, a sensory map was
drawn in relation to the medial aspect of the humeral head which represent (0 ) grade on
the scale i,e complete sensory blockade.
Twenty-four hours after performance of the ICBN block, sensory integrity of the
particular area was re-tested and compared to the contra lateral side to ensure accuracy
of the block and reduce the risk of bias.
Results
Twenty eight
male volunteers were included
in
the study analysis;
their
demographic data were included in table (1). US visualization of the ICBN was possible
in all cases. The mean horizontal nerve diameter was 2.3+0.28 mm (mean + SD) and the
mean depth was 9+0.28 mm. The nerve location in all cases was superior and posterior
to the axillary vein at a point where the axillary vein approaches the posterolateral border
of the Pectoralis Major muscle. The mean distance between the nerve and the Axillary
vein was 1.48 + 0.17 cm. The nerve visualized posterior to the lateral border of the
Pectoralis Major muscle at a mean distance of 1.7 + 0.54 cm and 5.6+1.4 cm proximal to
the medial aspect of the humeral head.
Blockade of the ICBN was successful in all volunteers. Comparing the sensory block
distribution of all the volunteers revealed, a constant sensory blocked area relative to the
medial aspect of the humeral head which could be assessed as the following : 6.3+ 1.6
cm anteriorly, 6.2+2.9 cm posteriorly, 9.4+2.9 cm proximally and 9.2+ 4.4 cm distally (Table
2). Figure (4) illustrates an example of the sensory distribution of a successful ICBN
block. We did not detect any related side effects within twenty four hours after nerve
blockade.
5
Discussion
This study describes the Sono-anatomy of the ICBN with subsequent blockade of this
small sensory nerve under real time ultrasound guidance. We were able to show that US
visualization of the ICBN within a fascial pocket was possible in all the cases.
The significance of ICBN as a supplement to brachial plexus block for shoulder surgery
has been recognized for many years, especially for Bankart procedure (6, 7). Raj (8)
suggested intercostal T2 block at the posterior axillary line to cover ICBN sensory area
while Balas (9, 10) performed T2 blockade through paravertebral approach. However,
axillary subcutaneous infiltration to peripherally block the ICBN endings remained the
most popular approach. The later involves injection of local anesthetic subcutaneously
forming a wheal along the axillary crease from the anterior head of the Deltoid muscle
to the long head of the Triceps muscle (4).
We know from our earlier experience that small nerves can be visualized by the use of
Ultrasound and successful blockade is feasable (5), and the operator should rely on a
prominent anatomical sono-landmarks. Identification of the axillary vein and the lateral
border of Pectoralis Major muscle, and more importantly; the relationship between the
above two anatomical structures are required to localize the potential area of ICBN. The
ICBN is best identified where the axillary vein approaches the lateral border of the
Pectoralis Major muscle. The dynamic image was more helpful than static one. As the US
probe was moved towards the apex of the axilla, the nerve fibers are
smaller branches
dividing into
running in more superficial plane. Moreover, the ICBN either passes
near or cross-over the axillary lymph node (11), and the dynamic image in such case is
a more reliable method to outline the ICBN from the neighboring structures. The operator
should keep in mind the superficial course of the ICBN in the axillary fossa, and not to
be confused with other nerves running at deeper plane such as the Long Thoracic and
Thoracodorsal nerves.
The blocked sensory area was semi-rounded shape and distributed around the medial
aspect of the humeral head, therefore, in order to obtain an informative map, we’ve
chosen this anatomical bony landmark to be the center of ICBN sensory map. Moreover,
many volunteers experienced numbed area reaches distally as far as the medial aspect of
the elbow joint, but we choose to map area graded as “0” on the sensory scale only.
6
The volunteers in this study were all male gender, have normal or low body mass
index; therefore, our observation might not be applied to patients with higher body mass
index or female gender.
In Conclusion Our results show that US can be used reliably to visualize the ICBN, and
injection of one ml of local anesthetics under direct US visualization can successfully
block the ICBN which can be used as a supplemental block for upper limb anesthesia.
We recommend further studies to support this finding and to apply these finding to
improve patients care
References:
1. Loukas M, Hullett J, Louis RG, Jr., Holdman S, Holdman D. The gross anatomy of the
extrathoracic course of the intercostobrachial nerve. Clinical Anatomy 2006; 19:106-111.
2. O’Rourke MG, Tang TS, Allison SI, Wood W. The anatomy of the extrathoracic
intercostobrachial nerve. Australian & New Zealand Journal of Surgery 1999; 69:860864.
3. Abram S. Central hyperalgesic effects of noxious stimulation associated with the use of
tourniquets. Reg Anesth Pain Med 1999;24:99-101.
4. Urmey WF. Upper Extremity Blocks. In: Brown DL, ed. Regional Anesthesia and
Analgesia. 1st ed. Philadelphia: Saunders; 1996:254-278. (ICBN BLOCK
DESCRIPTION).
5. Thallaj A, Marhofer P, Kettner SC, Al-Majed M, Al-Ahaideb A, Moriggl B. Highresolution ultrasound accurately identifies the medial antebrachial cutaneous nerve at the
midarm level: a clinical anatomic study. Reg Anesth Pain Med. 2011 Sep-Oct;36(5):499501.
6. Adriani J. Labat’s regional anesthesia, techniques and clinical applications. Philadelphia:
WB Sunders, 1967:242-59.
7. Mitchell EI, Murphy FL, Wyche MQ, Torg JS. Interscalene brachial plexus block
anesthesia for the modified Bristow procedure. Am J Sports Med 1982;10:79-82.
8. Raj PP. Ancillary measures to assure success. Reg Anesth 1980;5:9-12.
9. Balas GI. Regional anesthesia for surgery on the shoulder. Anesth Analg 1971;50:103642.
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10. Dekrey JA, Balas GI. Regional anesthesia for surgery on the shoulder. A review of 1500
cases. Reg Anaesth 1981;4(7):46-8.
11. Taylor KO. Morbidity associated with axillary surgery for breast cancer. ANZ Journal of
Surgery 2004; 74:314-317.
Figure legends
Fig (1):
Simulation of US probe and needle position for in-plane ICBN block technique
The circle: denotes the medial aspect of the humoral head
The curved line: denotes the lateral border of the pectoralis major
Fig (2):
A: US short axis view at the base of the axillary area
Shows the ICBN as an oval shaped hyper-echoic structure posterior to
Lateral border of the Pectoralis Major muscle, superior and posterior to the axillary vein
B: Diagram of short axis view at the base of the axillary area
PM: Pectoralis Major muscle, ICBN: Intercostobrachial nerve.
AX: Axillary vein
Fig (3):
Us short axis view at the base of axillary area after reducing the depth to 1.5 Cm for clear ICBN
visualization; note the fascicular structure of the nerve
PM: Pectoralis Major muscle, ICBN: Intercostobrachial nerve.
Figure (4):
Illustration of a case of a sensory block distribution 10 min after ICBN blockade
HH: Medial aspect of the humeral head
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Table (1): Patient’s Demographic
No. of volunteers
28
Sex
All males (n = 28)
Age, yrs
35.1+12.2
BMI
24.6+3
Data expressed as Mean+SD
Table (2): Sensory blocked area relative to the medial aspect of the humeral head
-
Anterior
6.3+1.6
-
Posterior
6.2+2.9
-
Proximal
9.4+2.9
-
Distal
9.2+4.4
Data expressed in cm (Mean+SD)
9