Regional Anesthesia Education Initiatives

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Category #5 - Blocks above the clavicle (CPVD, ISB, SCB)
Cervical Paravertebral Block for chronic pain CCPVB for shoulder surgery
Cervical Paravertebral Block for chronic pain
Question:
"I did the first cervical paravertebral block as described by Boezaart in a patient with complex regional pain syndrome of the right upper limb. Everything went smoothly and exactly as described in the excellent movie. The patient reported sensation just before muscular twitches. When the current was decreased to 0.04 milliamps with very minimal muscle twitches, the patient was still reporting "paraesthesia". I needed to dilate the space with 10 ml of .4 and 10 ml of .2% ropivacaine before I could thread in an ordinary epidural catheter. The result was good but the patient reported difficulty in breathing and also hoarseness. Three dimensional x-ray reconstruction confirmed spread of local anesthetic agent anterior to the nerve root spanning from C-4 to T-1. The right vocal chord paralysis could also be seen. After six hours, the hoarseness disappeared, the patient was complaining of discomfort in the neck and insisted on catheter removal". Why the neck discomfort?
Answer:
Thank you for your interesting questions. I think chronic pain scenarios as you describe is a bare landscape that begs to be visited by continuous nerve blocks. This block that you described is not consistent with the block described by me in the movie nor the literature. I suggest that you revisit the movie since I do not advocate, "dilating the space", and I certainly do not advocate the use of an "ordinary epidural catheter". I use stimulating catheters and "dilating the space" makes this impossible. The finding of sensory pulsations down the arm (which you call "paraesthesia") is very common especially in young people, since the roots of the brachial plexus are approached from posterior, where the roots have already split into sensory posterior fibers and anterior motor fibers. The pain that this patient complained of in the neck is very common with catheter procedures from posterior, as opposed to single-injection approaches from posterior as reported in the recent literature (see Anesth Analg 2005; 100: 1496 - 8 and Reg Anesth Pain Med 2005; 30: 238 - 242). When we started doing this block some 8 years ago, our first 48 patients all complained of posterior pain and this was due to the catheter penetrating the extensor muscles of the neck. As our experience grew, we learned that there is a "window" between the trapezius muscle and levator scapulae muscle at the level of C6. Entering between these muscles and pushing these muscles apart with the fingers of the non-operative hand, will ensure that your future patients do not have this neck pain. The ones that do, it is my contention, are the ones in who you were not successful in separating these muscles and you actually penetrated them. In our institution, we typically get severe neck pain in patients in the July to October period of our academic calendar, since that is the time that the new residents and fellows are still inexperienced with this block. After November, they usually start to comprehend this and this is normally the end of the problem until the end of June the next year. Again, I would urge you to study the movies on the website (http://RAEducation.com) and perhaps download this particular movie and Tutorial. This is certainly an advanced block and should not be viewed as a basic block and should not be done by people who do not frequently perform continuous nerve blocks. In our pilot study, the first 48 patients all had major shoulder surgery and all of them reported that the shoulder felt great but they all requested that we remove the catheter because of the severe pain in the neck (see Reg Anesth Pain Med 2003: 28: 406 - 13). This is similar to your experience. The vocal chord paralysis is obviously due to recurrent laryngeal nerve paralysis and as you know, the recurrent laryngeal nerve is a branch of the vagus nerve and this nerve is frequently blocked with most approaches to the roots of the brachial plexus. I take exception to the ill-informed and sarcastic reply of Michael F to your question posted on the NYSORA website, but I do agree with Jeffrey (I assume that is you) who replied on May 28th. The reason why your patient suffered pain in the neck only later, was obviously because the regional anesthetic that you used to place this block had worn off by then. To answer Jeffrey's questions; if he looks at the transection of the neck as posted in the tutorial and movie sections of the RAEducation.com website, he will see how far the extensor muscles of the neck does go lateral. This is usually not further than the lateral border of trapezius at the C6 level. I also agree that ropivacaine 0.2% may solve the motor paralysis problem that Jeffrey has but the motor sparring is not the only reason why I prefer the posterior approach. The other reasons are that it is easier to do and to teach, it is the only continuous nerve block needed for the entire upper extremity and our results with it have been spectacular. In fact, since we removed the continuous interscalene block from our practice, we have peace and quite from our surgical colleagues and our patients. But again, this is NOT a basic block and should NOT be done by occasional regional or orthopaedic anesthesiologists. Finally, the ignorance of Michael F. is eloquently displayed in his follow-up letter where he actually admits that he has never done this block before. I would therefore, urge you not to pay any attention to his recommendations. I trust that this explanation may add some value to your practice. Please feel free to make liberal use of our "Ask the Experts" section on the website (http://www.RAEducation.com) and remember to nominate the expert that you would like to answer your questions. Yours Sincerely Andre P. Boezaart, MD, Ph.D

CCPVB for shoulder surgery
Question:
Why is the posterior approach a better choice for arthroscopic surgery of the shoulder? Is that because its relative motor sparing effect?
Answer:
There is no definite data available in the literature to answer this question so the best I can do is to provide you with my personal opinion on this matter. Motor sparing is one of the big advantages of the posterior approach or the cervical paravertebral block but it is not the only advantage. Other advantages include the fact that, certainly in our experience, we do not threaten the area of maximum irritation of the brachial plexus namely where it crosses the first rib with this approach. Many cases of arthroscopy of the shoulder and subacromial decompression are because of existing brachial plexitis, which causes shoulder pain. The patient ends up at the office of a shoulder surgeon who does what a shoulder surgeon does, namely operate the shoulder. It is wise if the patient complains of pain distal to the elbow not to do a brachial plexus block for this patient until the pathology becomes clear, since pain and paresthesia distal to the elbow is almost never a symptom of bona fide shoulder pathology. Other reasons why we prefer the cervical paravertebral block, which by the way is not a basic block and should not be performed by people who only occasionally do regional anesthesia, includes the fact that you can use one block (well) for any major surgery of the entire upper limb and you therefore, do not have to learn or teach any of the other procedures like continuous interscalene block, continuous supraclavicular block, continuous infraclavicular block or continuous axillary block. All four blocks have good indications but with experience, you will find that their performance is disappointing to say the least. If the cervical paravertebral block replaces all four continuous blocks, you will have peace and quiet in your practice. This is an easy block to do and an easier block to teach since there is a boney backstop which removes complexity but it has rules and these rules have to be obeyed diligently. When Kappis described the cervical paravertebral block for the first time in 1912, he noticed that all the dangerous structures in the posterior triangle of the neck are situated anterior to the brachial plexus. This includes the vertebral arteries, artery and veins, all the big arteries of the neck and all the other nerves that one does not want to block. It therefore makes perfect sense to approach the brachial plexus from posterior. When Kappis first described this block, he did not have access to a nerve stimulator and he did not know when he went through the brachial plexus other than by eliciting paresthesia. If however, you did not get paresthesia, it was possible to penetrate the brachial plexus and structures anterior to the brachial plexus. Nowadays, with the use of modern nerve stimulators, you will have a definite motor response when you get near the brachial plexus with the needle. As previously said no studies that compare the interscalene block with a paravertebral block has been done and I am anxiously awaiting these studies. Please note again that the above is only my personal opinion but I do hope that it satisfactorily answers your question. Please feel free to contact me personally if you do have any further question or to pose any further questions on the website. Please note that you are free to address your questions to any of the superb panel of experts that we have available for you. Yours sincerely, André Boezaart


Question:
What are your thoughts on pectoral versus deltoid twitch when performing an interscalene block?
Answer:
Both of these responses are adequate, since both of these responses are derived from the brachial plexus. In fact, we accept any brachial plexus response from the anterior shoulder, pectorals, arm or hand. For interscalene block, we are most comfortable with a biceps twitch. However, it is essential that the response seen is indeed a plexus response. When performing an interscalene block, there are several motor responses that can be seen that may confuse the practitioner. A true deltoid twitch occurs when the 5th and 6th cervical roots are stimulated. However, stimulating the dorsal scapular nerve will result in twitching of the rhomboid muscles. The rhomboid stimulation via the dorsal scapular nerve draws the vertebral border of the scapula medially and upwards. This movement can easily be confused with a deltoid twitch, but its blockade will certainly not be confused with analgesia. Likewise, the nerve to levator scapula and the 11th cranial nerve to trapezius can falsely resemble a deltoid twitch. As a general rule of thumb, any anterior chest and arm motor response will result in a successful interscalene block, while posterior chest motor responses (rhomboid for example) will result in a failed block. Motor responses in-between (deltoid) can cause confusion.


Question:
Do you find that you get ulnar sparing when using the posterior approach to the interscalene space?
Answer:
We do not typically find ulnar sparing with the cervical paravertebral block. In fact, we have had very good success with the CCPVB for wrist, elbow and hand surgery. The reason is that this block is done on the level of the roots of the brachial plexus, which are in the same compartment.



Question:
What is the loss of resistance in a cervical paravertebral actually caused by?
Answer:
The loss of resistance in the CCPVB is more correctly a change in resistance that is found when the needle tip passes through the attachments of the medial and posterior scalene muscle to the transverse processes of the vertebrae into the space between the anterior and middle scalene muscles.



Question:
Why do you use loss of resistance with a cervical vertebral block?
Answer:
The loss of resistance in the CCPVB is more correctly a change in resistance. It is much more subtle than the loss of resistance appreciated when passing through ligamentum flavum, for example. As a result, we perform the loss of resistance with nerve stimulation as a means to appreciate the subtlety of the change of resistance present when doing this block. This allows us to perform this block post-operatively where motor responses due to nerve stimulation are painful and undesirable, through only the loss of resistance technique, when necessary. It is also better to have two positive confirmatory tests of correct needle placement than one.


Question:
How can I learn more about the cervical paravertebral block?
Answer:
Please visit the RA Education website at http://RAEducation.com and download these movies. There are three movies on the CCPVB. One is a 3-minute movie, a 10-minute workshop and a full demonstration of the block. You will also find a full narrative on the block. Please also see Reg Anesth Pain Med 2003: 28: 241 - 244 and Reg Anesth Pain Med 2003; 28: 406 - 413 for the original description and our experience with the first 256 CCPVB/s.


Question:
What is your experience with CCPVB in kids?
Answer:
My personal use of cervical paravertebral block in kids is limited to oncology patients and trauma. As you know, kids don't get shoulder operations for the usual adult indications and I actually believe that is why nerve injuries are so seldom seen in kids. Kids just don't get interscalene blocks. And interscalene blocks with the Winnie approach is in my opinion and experience responsible for most of the nerve damage that we see and read about. It has nothing to do with awake vs. asleep. My shoulder blocks in kids are for kids with shoulder and humerus surgery due to bone tumors or fractures. Here I use the paravertebral approach and do it under GA after explaining our (prevailing wisdom) approach and possible higher incidence of complications of blocks under GA to the parents (although I seriously do not believe this to be true!). If not under GA, I use remifentanyl 0.3 - 0.5 microgram per kg as bolus for the placement of the block.