Electrophysiological Efficiency of Surgical Treatment of Patients with Generalized Myasthenia Gravis
Author`s Contribution:
- Kharkiv National Medical University, Ukraine
- V. T. Zaycev Institute of General and Urgent Surgery of NAMS of Ukraine, Ukraine
Background and aim of study:
Myasthenia gravis (MG) is an autoimmune disease, the
basis of the pathogenesis of which is the autoimmune
process directed against the nicotine acetylcholine
receptor of the postsynaptic membrane of the muscle.
The pathogenetic mechanisms of the MG development
are closely related to thymus. Thymectomy
(thymomectomy) allows to achieve a high percentage
of remissions (60–80%). The use of
electrophysiological research methods is an important
element in the evaluation of the efficiency of treatment
of different clinical forms of MG, including surgical
treatment. The aim of the study was to estimate the
efficiency of surgical treatment of patients with
generalized MG using the analysis of the functional
state of neuromuscular synapse in the early and last
postoperative period.
Research methods:
The study was carried out in the myasthenic center
established in 2007 on the basis of the
thoracoabdominal surgery department of the GI
“Zaycev V. T. Institute of General and Emergency
surgery of the National Academy of Medical Sciences
of Ukraine” and the GI “Institute of Neurology,
Psychiatry and Narcology of the National Academy of
Medical Sciences of Ukraine”. The study group
consisted of 342 patients with a generalized MG.
Thymectomy (thymomectomy) was done to 263
patients. To study the effect of surgical treatment on
the basic parameters of the functional state of
neuromuscular junction, we used the values of “Delta”.
Results:
Analyzing the average values of changes of the main
neuromuscular transmission parameters after
thymectomy, thymomectomy in “Delta”, the following
features were identified: thymectomy, thymomectomy
had an immediate fast effect on muscle force, leading
to its increase by an average of 2 points, already in the
first days after the operation; the rapid increase in
muscle force corresponds to the effect of reversibility
of neuromuscular transmission disorders, manifested
by a significant increase in the amplitude of the Mresponse (144.4–166.4%) and the expressed decrease
in the decrement (by 22-27%). Thus, as a result of
thymectomy, thymomectomy, a very rapid change in
the functional state of the synapse occurs with the
restoration of all the affected neuromuscular links.
Nevertheless, the described immediate effect of
thymectomy, thymomectomy did not remain in all
patients further.
In comparison, in the late postoperative period (within
12 months after surgery), the maximum effectiveness
of surgery (complete remission, with no manifestations
of MG; a condition that does not require the use of
immunosuppressive therapy, even in maintenance
doses) depend on the type of synapses pathology. In
patients with Type I of MG maximum efficiency of
thymectomy, thymomectomy was noted in 64.8% of
cases, with Type II – in 23.5% and with Type III – only
in 15.0%. Accordingly, the lack of effectiveness (a
slight improvement in the state or lack of effect that
does not allow to reduce the dose of anticholinesterase
and glucocorticoid drugs by more than 50.0%) or
negative effectiveness of thymectomy, thymomectomy
was detected in 25.7% of patients with Type I, 70.7% –
with second and 80.0% – with third types of synapse
pathology.
Conclusion:
Evaluation of the results of the electrophysiological
study of patients with a generalized MG suggests that
there is an immediate efficiency of thymectomy,
thymomectomy, which in most patients manifests an
explicit improvement in the state and does not depend
on the type of synapses pathology. In studying the
long-term efficiency of thymectomy, thymomectomy,
we found a clear dependence between the type of MG
and the results of surgical treatment. Thus, the
objective evaluation of the efficiency of thymectomy,
thymomectomy should not be carried out earlier than
12 months from the operation. At the same time, it
should be noted that the results of such an evaluation
may be significantly different from the initial (in the
early postoperative period).
Keywords:
Copyright:
DOI and UDC:
DOI: 10.26697/ijes.2019.2.46; UDC:616.74-009.17:591.147.3-006.6]-089:612.014.42
Information about the authors:
Minukhin Dmitriy Valeriyovych – Doctor of
Philosophy in Medicine, Assistant Professor of
Department of Surgery No. 1, Kharkiv National
Medical University, Kharkiv, Ukraine.
Klimova Elena Mihaylivna – Doctor of Biological
Sciences, Professor, Head of Diagnostic Laboratory
with Immunoenzym and Immunofluorescence
Analysis, V. T. Zaitsev Institute of General and Urgent
Surgery of NAMS of Ukraine, Kharkiv, Ukraine.
Yevtushenko Denys Oleksandrovych – Doctor of
Medical Sciences, Professor of Department of Surgery
No. 1, Kharkiv National Medical University, Ukraine.