Leprosy Mailing List – March 11, 2021
Ref.: (LML) Neurophysiological comparative response to clinical and surgical treatment of the ulnar neuropathy in leprosy
From: Been Naafs, Munnekeburen, the Netherlands
Dear Pieter,
As you know, I am interested in nerve surgery and after working with Dr. Jan Van Droogenbroeck at ALERT in the 1970s, I became convinced that it was a valuable addition to the drug treatment of neuritis. That time there was much opposition against surgery, and it remained a matter of controversy as hardly objective comparison studies with medical intervention alone were done. One of the few studies was a left-right study done by Dr Van Droogenbroeck in the mid-1970s (1)and the one written by Dr E Wan et al. (2).
A few years ago, the ILSL decided to conduct such an investigation. This was not an easy undertaking. A lot of data became available. And after many years, under the responsibility of Dr. José Garbino, the electrophysiological part of the study was analysed and published. He sends me the published study (3). In the past he has written many papers on electrophysiological studies, before reading this study it is worthwhile to read: Neurophysiological patterns of ulnar nerve neuropathy in leprosy reactions (4).
It is a pure electro-neurophysiological study; possible function enhancements in Graded Sensory Testing and Voluntary Muscle Testing have not yet been analysed.
Patients with active neuropathy (clinical and electro-neurophysiological) 1-3 years after the start of treatment were included, provided that the ulnar nerve complaints were within the past six months. So, they were mainly patients with a long-standing neuropathy, but active in Type I Reaction within the last 6 months.
After one month of drug (steroid) treatment, the patients who showed no clinical and electro-neurophysiological improvement were randomly divided into two groups: one continuing drug therapy alone and one with additional surgical treatment. Drug treatment was the same in both groups based on clinical assessments. It could therefore be that the surgical group after some time received less steroids. But that must be seen after further analyses.
The neurophysiological follow-up consisted of the composite motor action potential (CMAP), distal latency (DL), conduction velocity (CV), the temporal dispersion around the elbow (TD) [surgery was performed here] and the F wave. The electro-neurophysiological criteria for acute or sub-acute demyelination were a TD greater than 50% and a CV less than 30% of normal limits. A conduction block was assumed when there was an amplitude reduction of the CMAP over the elbow of more than 30%.
The surgical technique was meticulous, based on the technique of Duerksen, Sirinivassan and Palande. The blood supply was preserved as much as possible.
The results before and after 1-3 years were compared.
Fifteen nerves were operated on and 12 nerves were treated with medications only. Two nerves were damaged too much, and these were analysed separately. There was no significant difference between the two groups.
The classification for everyone was Borderline.
It was found that the CMAP measured from all stimulated points (wrist, below elbow and above elbow) was significantly better for the surgically treated nerves. Two patients with Martin-Gruber were excluded from elbow stimulus analyses.
The temporal spread over the elbow shows more improvement in the surgically treated nerves compared to the medically treated nerves (in a trend line but not significant p = 0.08).
There was an improvement in CV between the two groups in favour of the surgical group between the 4th and 6th (final) evaluation (p = 0.027). But not between the first and the last evaluation. This is a strange finding. Was there a deterioration between the 1st and the 4th evaluation?
All other electro-neurophysiological parameters showed no significant change between groups.
The nerve with no motor response was as expected also unresponsive after surgery.
In the discussion the authors again note the significant improvement in CMAP's amplitude and state that this is the most sensitive parameter for nerve repair (it is unfortunate that this was only a neuro-electrophysiological paper, it would have been nice to see whether VMT and ST had improved).
They argue that the increase in CV is due to remyelination and decompression. (But why only between the 4th and the 6th and not between the 1st and 6th measurements?)
The TD deteriorated in 4 nerves, indicating new demyelination: a new type I response occurred in the 2 only medically treated patients. Subluxation was observed in the 2 operated patients.
In general, there is an improvement in some of the electro-neurophysiological parameters, but what is the benefit for the patient? It is agreed that one of the main indications of surgery is pain relief. This has not been assessed in this study.
The authors focus on electro-neurophysiology. Thus, this article is of particular interest to readers of LML using electro-neurophysiological studies.
I hope in future they can also analyse the other data collected.
References:
1.Van Droogenbroeck J.B.A. et Naafs B. Etude comparative d'une série de nerfs lépreux décomprimés chirurgicalement par rapport aux nerfs contralatéraux non-opérés. Méd. Trop. 1977;37: 771-776
2. Wan EL.,Noboa J. , BaltodanoPA., Martinez JousinR., EricsonWB., WiltonJP.,RossonGD., Lee DellonA.; Nerve decompression for leprous neuropathy: A prospective study from Ecuador; Leprosy Review; 2017; 88; 1; 95-108; DOI: 10.47276/lr.88.1.95
3.Borela MCM, Cury Filho M, Kirchner DR, Salgado MH, Virmond MCL, Garbino JA. Neurophysiological comparative response to clinical and surgical treatment of the ulnar neuropathy in leprosy. Acta Fisiatr.2020;27(3):125-130. DOI: 10.11606/issn.2317-0190.v27i3a166868.
4. Garbino J.A.,Naafs B, Ura S., Salgado M.H., Virmond M.Neurophysiological patterns of ulnar nerve neuropathy in leprosy reactions. Lepr Rev 81 (2010), 206-215
LML - S Deepak, B Naafs, S Noto and P Schreuder
LML blog link: http://leprosymailinglist.blogspot.it/
Contact: Dr Pieter Schreuder << editorlml@gmail.com
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