In leprosy axillary and cervical nerve blocks are not recommended

Leprosy Mailing List – February 1^st, 2010

Ref.: In leprosy axillary and cervical nerve blocks are not recommended

From: Grace Warren, Sidney , Australia

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Dear Salvatore,

I note with interest the various responses to the letter from Angelika (LML Jan. 23^rd Jan. 2010). I am fascinated by the many suggestions and yes I understand that the tight tourniquet could be a problem and has caused many problems but, I would be grateful if this paper of mine could be included to show workers that they do not need to inject the nerves directly and in a patient with marked nerve damage the extra needle damage may well be the last straw and produce the paralysis. I have seen it in non-leprosy people with otherwise normal nerve function, sometime producing severe lasting pain sometime producing paralysis.

In Leprosy we can never be sure exactly how much of a nerve has been damaged or completely destroyed and/or if we have got rid of all the infection that is destroying or has destroyed that group of nerve fibres, and hence if there is ever likely to be a further neural deficit in the future.

For good rehabilitation as soon as diagnosis is made, we should strengthen every muscle in the limb to its maximum and assess the detailed function of all nerves affected. Some nerve may have been damaged and yet may recover with time and good medication. Every patient with nerve damage in the arm, ought to be taught full hand exercises. Details of these exercises, are given in my book “The care of the neuropathic limb” (Parthenon – 1999). I will ask Dr Noto to publish a revision of those exercises in the LML. The idea is to help physiotherapists and other involved health workers in restore fuction in weak intrinsics etc.

After the disease is controlled and the muscle function has plateaued we can then assess what measures, surgical or otherwise can assist that person to rehabilitation.

In leprosy the nerves are involved very early in the disease but may not show a deficit for a prolonged period of time. When the nerve is damaged it does not show obvious deficient function until about 10% (some say 15%) of the nerve fibres of any one modality are damaged, so palpating a nerve may suggest it is OK but in fact some 6-8-10% of its fibres may be NON functioning and yet there is no obvious sign of the functional deficit.

Even skilled technicians cannot detect the functional deficit, initially, and may say ”No obvious deficit”- so when assessing a hand with a weakness of thumb opposition for example, one must assume that there is a weakness of the other medially innervated intrinsic muscles and even if not detectable at present there will be some deficit of the other modalities of that nerve in the future or there will be some sensory abnormality even if one cannot record anything definite. All the nerves in the arm are likely to be affected to some degree even if we cannot record it.

It is also wise to remember that in lepromatous leprosy the nerve damage is not obvious early and I have had patients who were initially “ cured” of the active infection before 1960, and recorded as “No neural deficit” and developed a neural deficit in the 1970s! Was this just that the continuation of the “healing” fibrosis in the nerves from the disease has eventually squeezed the life out of the remaining fibres or was it relapse? It was not obviously relapse as no other lesions were found just a progressive (usually ulnar) palsy! So One should bear this in mind when planning surgery so that one selects muscles for transfer carefully so that there are possibilities available if something further is needed in future.

The basic treatment of the patient is important in the long term rehabilitation of the patient. If the patient has any other disease like tuberculosis, typhoid or just a septic foot, anaemia, some intercurrent disease. Is he malnourished? We cannot expect good recovery for the malnourished!

When a nerve block is put in it is aimed at defunctioning some of the nerves, albeit temporarily. However in most nerve blocks one manages to damage some nerves permanently! I assume just by the needle hitting the nerve and I realised this to my disgust many years ago (in the i960s!). When I had two patients, within a few months, who developed radial nerve palsy from brachial plexus anaesthesia. As a medical student I had discovered that a cervical plexus block was more likely to produce problems and it is also much more difficult to put in for people who are not yet fully experienced. When I have to use an arm block now I use an upper arm or brachial block, which is much easier to insert and just as good for anything below the elbow.

For operations on leprosy patients the use of general sedation and ketamine is usually more than adequate, supplemented by a little local at incision sites if needed. Most of them if they have a paralysis due to leprosy also do have reduced sensory perception, and a good sedative plus ketamine is usually effective. However for that, one needs a suitable assistant to give the anaesthetic as he may need respiratory assistance or other medication. In many situations there is not other “doctor” to help.

An excellent alternate method is a “Biers Block” using a tourniquet on the arm and then injecting local anaesthetic into the vessels distal to the tourniquet . This is effective if one knows one can do the surgery within the hour or so .

The good old Karigiri Cocktail is excellent requiring NO injection of nerves and I still use that when a good anaesthetic doctor is not available. In many centres that I have visited teaching over the years, I have used Karigiri Cocktail by choice as I know it well and the patient has no post op discomfort from the anaesthetic! Again a good sedative with properly given preoperative sedation, seconal and phenergan and later morphine and scopolamine and Intravenous pethedine and largactil! (I wrote it up in Leprosy review in 1974!).

Second I note two of the hands used Palmaris tendon as the transferred tendon . We know it is never very strong . Sometimes I suspect the patient can never use it in isolation. I rarely if ever use it as an active transfer . If they can work it, it is very weak and not really strong enough to give a good thumb opponents as the patient needs a strong grip and Palmaris will never give that! Nor will the Extensor Pollicis Longus. Yes I have used it as a tenodesis for an intrinsic replacement when there is nothing else one can steal!

The object of the operation is to improve function and many of our patients need a strong grip . I often used is as a graft when it was not convenient to get a piece of leg fascia . I wonder what graft the surgeon used to extend Palmaris so it would reach the thumb? (aH I see fascia lata for at least one case) . So I would recommend that before any surgery the patient does 3 months of good physio under supervision (but he or she does it all himself) strengthening every muscle available and then make the assessment as to what to use. If you do not want a sublimus for opponens of thumb (it is the best usually I think) then the Flexor carpi radialis muscle can be quite effective or a wrist extensor (NOT flexor carpi ulnaris) that is too important in stabilising the wrist) - but in leprosy I rarely use Extensor carpi radialis longus or Extensor carpi radialis Brevis as the chances of needing an intrinsic is great- also the Pronator teres is excellent if done the correct way!, even brachioradialis in a very bad arm!

We always have to take into consideration the possibility that there is further progression of the neural deficit and be prepared to deal with it! Patients may have multiple bouts of paralysis because of relapses and inadequate therapy in the initial stages. The MDT regimens as suggested by WHO may be inadequate.

Now, in the first case mentioned I see weak thumb muscles I wonder how weak? And I wonder if intensive exercises would have restored enough function to have eliminated the need for surgery.

I note he used fascia as graft would have been easier to use Flexor carpi radialis as motor and palmaris as graft! Sounds now as if he will need a full radial nerve reconstruction . It is unlikely that the nerve will recover from the block injection . The steroids not much use, certainly do not give for more that 6 weeks at the most and as the nerve only regenerates at 1 inch per month it will be many months before one can say nothing doing! I advise all patients have Multivits with at least 10mgms Vit B and Vit C and zinc before and after surgery and for a t least a few months after .

Case two . Horrors high medial palsy as well, that arm is going to be a real challenge . No use giving steroid to long! That result means that the transfer does not work and apparently there is no long muscle left that is going to be worth transferring . Work with him 6 months to maintain mobility and then re-assess .

I do not mind if you write then and say what muscles do function and their strength I use the 0-5 voluntary muscle test (VMT) scale . Electrical tests do not really help . It is what the patient can do himself that counts . A wrist brace all the time now (in the post operative period). It may help him to try and use the fingers to encourage reuse of any nerve/muscle fibers still intact . I have produced some amazingly functioning arms is cases like this if the patient is realty prepared to persist and we get tensions etc correct ..

Case three is much the same. Do not try and rush. Remember the nerves re-grow at one inch per month! And from an axillary damage it is many inches to the muscle affected!

I hope this will warn THAT IN LEPROSY (and some other diseases) AXILLARY AND CERVICAL NERVE BLOCKS ARE NOT RECOMMENDED for reconstructive surgery . And people on poor diets or with other diseases need all the assistance they can get medically to encourage return of function of partly affected nerves .

Dr Grace Warren

The Hong Kong Leprosy Hospital., Hay Ling Chau 1959-1975;

Adviser in Leprosy and Reconstructive Surgery for The Leprosy Mission in Asia 1975-1994.