Question:

What corrections do you make with the needle and catheter when performing an infraclavicular block?

Answer:

Nowadays we do most of our infraclavicular blocks with ultrasound only.  We identify each cord and place the local anesthetic agent on that cord.

If, cowever, you don’t have access to ultrasound, corrections, or redirections, are  essential components of successful peripheral nerve block placement. In fact, it is in cases when redirections are needed that a strictly landmark-based approach would result in block failure. The important point about redirecting a needle or catheter is to understand the relationship between the elicited and desired motor response, and to understand the changes necessary to achieve the desired response. In the case of an infraclavicular block, knowledge of the relationship of the brachial plexus cords is essential. Since the cords are named after their relationship to the 2nd portion of the axillary artery, we know that the posterior cord will be further posterior to the lateral cord, and will redirect in that manner if a lateral cord response is found while a posterior cord response is desired (see Reg Anesth Pain Med 2004; 29: 125 – 9).

Basically you have to look at the pinkie:  “At the cords, the pinkie towards”.  If the posterior cord is stimulated, the pinkie moves posterior.  If the medial cord is stimulated, th epinkie moves medial.  And if the lateral cord is stimulated, the pinkie moves lateral (pronation of the hand).

Also, if you get a musculocutaneous nerve (biceps) or axillary nerve (deltoid) ISOLATED twitch, do not accept it and move the needle a little deeper.  A pectoralis major twitch means the needle is too anterior and it needs to be redirected more posterior.  If, lastly, the arm rotates it means the nerve to subscapularis muscle is stimulated and the needle is too deep.

Question:

Which infraclavicular landmark do you find most reliable?

Answer:

Most, if not all of our infraclavicular blicks, ultrasound or nerve stimultor, are done in the sagittal plane from a point just caudad of the clavicle in the deltopectoral trough. The classical landmarks as described through the years (VIP, pericoracoid, line from interscalene groove to deltopectoral groove (not to be confused with deltopectoral trough), however, will all typically result in a confluence of lines that outline the expected path of the brachial plexus, and the best approach to the cords of the plexus would be through this trough.  The deltopectoral trough is bordered by the clavicle cephalad, the pectoralis minor on its implant area on the coracoid process lateral, and the pectoralis major muscle medial.  An ultrasound probe placed in the trough in the sagittal plane make the artery easily visible.   Doppler identification of the artery is also useful for orientation. We have started to use this “superior approach to the cords” some years ago, in which we pass our needle directly under the clavicle at a point where the indentation just medial to the coracoid process is (see “Anesthesia and Orthopaedic Surgery”, Ed A P Boezaart, McGraw-Hill, Chapter 24, or Atlas of Regional Anesthesia and Anatomy for Orthopaedic Surgery, A P Boezaart. Elsevier, New York 2008). This approach may offer the advantage of less patient discomfort due to the avoidance of penetrating the pectoral minor or major muscles, a more direct route to the posterior cord with less risk of axillary artery puncture, and a less acute angle to the plexus that might make catheter placement easier to accomplish and ultrasound visualization of the needle better.

Question:

What cord do you preferentially block when doing an infraclavicular block?

Answer:

The location and type of surgery dictates what cord we preferentially block. If the proposed surgery falls in the distribution of a particular cord, we block that cord first, or place a catheter on it. For single injection blocks, it is our practice to locate all three cords, or at least two of the three cords, inject on the cord that is most appropriate for the surgery, then seek out the remaining cords and block them. We also have very good success when we block a combination of the posterior cord and one of the other cords (medial or lateral). (see Reg Anesth Pain Med 2004; 29: 125 – 9).  We have to obay Hilton’s Law of Anatomy though.  This Law states that a nerve that innervates a muscle that moves a joint or the skin overlying a joint, will also innervate that joint.  If one now thinks about that, all the joints of the upper limb are moved by muscles that are innervated by the entire brachial plexus.  This means that for any joint of the upper limb, the entire brachial plexus needs to be blocked.  The same is true for the lower limd and the lumbosacral plexus.

Question:

What do you think of a transarterial approach to the infraclavicular block?

Answer:

This is justifiably an outmoded technique.  In modern times most patients are on some sort of anticoagulat – even if it is only aspirin or NSAID, and if the artery bleeds, you cannot get to it to compress it like you can in the axilla.  Furthermore, we have much better ways of doing this block than that, but if you are alone in the middle of nowhere with only a needle and syringe, then okay, go for it (just kidding), but even then axillary block may be a better and more reliable choice.  If you are lucky the block may work, but I can almost guarantee you a failure if you don’t have the appropriate muscle twitches. We don’t want to rely on luck. These cords each lie in it’s own fascial sheath. We don’t try to get blood; if we do we regard it as a complication,  and even sometimes go for another approach,  i.e. supraclavicular or axillary. My advice to you is to forget that you ever heard about any trans-arterial techniques – axilla or infraclavicular, or anywhere else.

Question:

Can an infraclavicular block be used for gleno-humeral joint surgery? If yes, what are the concerns with the phrenic nerve? Please tell me a bit about the nerve supply of the shoulder joint.

Answer:

Of course infraclavicular block would be fine if combined with superficial cervical plexus block for the GH joint, since the axillary nerve supplies it. But if it involves the rotator cuff and subacromial and AC joints, you need to get the suprascapular nerve as well, which supplies the posterior parts of the rotator cuff, the subacromial joint and the AC joint. The articular branch of the lateral pectoral nerve, which comes off the lateral cord supplies the anterior parts of these joints, but remember that the medial pectoral nerve, which comes off the medial cord, has a connection to the lateral pectoral nerve. So ALL THREE the cords have to be blocked if the infraclavicular block is used for GH joint surgery (posterior goes to axillary, lateral to LPN and medial to MPN). Then the suprascapular nerve has to be blocked where it comes through the suprascapular notch or higher up in th einterscalene groove – and the superficial cervical plexus for good measure. Then if you are totally confused – do a GA, but if the lungs are so bad that you don’t want to do an interscalene, you probably don’t want to do a GA as well.

Remember severe COPD is not really a problem with phrenic nerve paresis. The diaphragms are flat in any case due to the hyperinflation in COPD of the lungs so they don’t really contribute to breathing. Granted it does not make the patient any better off to block their phrenics, but it likewise does not really harm them. Restrictive disease and mild to moderate COPD are, of course totally different stories.