The relationship between median nerve axon count and clinical findings and electrophysiological parameters in patients with carpal tunnel syndrome

Aim: To determine the association of clinical and electrophysiological findings in cases of carpal tunnel syndrome (CTS) using motorunit (axon) number estimation (MUNE) of the median nerve and to evaluate how these findings can contribute to treatment planning.Material and Methods: Evaluation was made of 43 hands of 25 patients (22 females, 3 males, mean age 45.63±9.89 years) with clinicaland electrophysiological diagnosis proven CTS and a healthy control group of 50 hands of 25 subjects (21 females, 4 males, meanage 44.72±8.89 years). Electrophysiological nerve transmission measurements and CTS grading were applied. MUNE measurementwas made from the abductor pollicis brevis (APB) muscle with the incremental method.Results: According to the electrophysiological grading, the mean MUNE values were at Grade-0: 134.66±41.00, Grade-1: 78.83±33.51,Grade-2: 71.72±32.15 and Grade-3: 50.25±27.45. A positive correlation was determined between electrophysiological grading andAPB muscle atrophy, and median nerve latency. A negative correlation was determined with MUNE, muscle strength, median nerveamplitude and conduction velocity. Between MUNE and muscle strength, median nerve amplitude and conduction velocity there wasa positive correlation, between MUNE and median nerve latency, a negative correlation was found. According to regresion analysis,median nerve wrist segment sensory velocity and median nerve distal motor action potential amplitude were predictive parametersfor MUNE.Conclusion: Together with the clinical evaluation, patients with grade 3 and/or MUNE value below 2 standard deviations of normalaccording to the electrophysiological evaluation, should be considered for surgery, while in milder cases, it can be recommended thatclinical and electrophysiological follow-up is added to conservative treatment.

PDF

___

1. Shawn CR, Kevin RV, Christine MF, et al. Carpal tunnel syndrome severity staging using sonographic and clinical measures. Muscle Nerve. 2015;51:838-45.
2. Ibrahim I, Khan WS, Goddard N, et al. Carpal tunnel syndrome: a review of the recent literature. Open Orthop J 2012;6:69- 76.
3. Wipperman J, Goerl K. Carpal tunnel syndrome: diagnosis and management. am fam physician. 2016;94:993-9.
4. Shapiro BE, Preston DC. Entrapment and compressive neuropathies. Med Clin North Am 2009;93:285-315.
5. Atroshi I, Gummesson C, Johnsson R, et al. Prevalence of carpal tunnel syndrome in a general population. JAMA 1999;282:153-8.
6. Padua L, Coraci D, Erra C, et al. Carpal tunnel syndrome: clinical features, diagnosis, and management. Lancet Neurol 2016;15:1273-84.
7. Pedersen K, Duez V, Stallenberg B, et al. Evolution of clinical, electrophysiological, and radiological aspects of the carpal tunnel syndrome before and after surgery. Acta Neurol Belg 2017117:903-8.
8. Ceruso M, Angeloni R, Lauri G, et al Edition. Carpal tunnel syndrome. springer-verlag ISBN 3-540-22387-8, Berlin Heidelberg New York, 2007;63-96.
9. Brown WF. A method for estimating the number of motor units in thenar muscles and the changes in motor unit count with ageing. J Neurol Neurosurg Psychiatry 1972;35:845- 52.
10. Mc Comas AJ, Fawcett PR, Campbell MJ, et al. Electrophysiological estimation of the number of motor units within a human muscle. J Neurol Neurosurg Psychiatry 1971;34:121-31.
11. Levine DW, Simmons B, Koris MJ, et al. A self-administered questionnaire for the assessment of severity of symptoms and functional status in carpal tunnel syndrome. J. Bone Joint Surg Am. 1993;75:1585-92.
12. Delisa JA, Lee HJ, Lai KS, et al. Introduction, technical procedures. Manual of Nerve Conduction Velocity and Clinical Neurophysiology (Third Edition). New York: Raven Press; 1994;12-22.
13. Leis AA, Schenk MP. Median sinir iletim çalışmaları. sinir ileti çalışmaları ve elektromiyografi atlası. Çeviri Editörleri Öge AE, Matur Z. İstanbul: Nobel Tıp Kitabevleri, 2014;42-57.
14. Jablecki CK, Andary MT, Floeter MK, et al. Practice parameter: Electrodiagnostic studies in carpal tunnel syndrome. Report of the American Association of electrodiagnostic medicine; American academy of neurology and American academy of physical medicine and rehabilitation. Neurology 2002;58:1589-92.
15. Padua L, LoMonaco M, Gregori B, et al. Neurophysiological classification and sensitivity in 500 carpal tunnel syndrome hands. Acta Neurol Scand 1997;96:211-7.
16. Stevens JC. The electrodiagnosis of carpal tunnel syndrome. Muscle Nerve 1997;20:1477-86.
17. Mine HS, Cemile BTY, Hüseyin ÖŞ. Autonomic involvement in carpal tunnel syndrome –sympathetic skin response and skin temperature. Neurological Sci Neurophysiology 2018;35:14-20.
18. Kohara N. Clinical and electrophysiological findings in carpal tunnel syndrome. Brain Nerve 2007; 59:1229-38.
19. Atroshi I, Gummesson C, Johnsson R, et al. Diagnostic properties of nerve conduction tests in population-based carpal tunnel syndrome. BMC Musculoskelet Disord 2003;4:9.
20. Srikanteswara PK, Cheluvaiah JD, Agadi JB, et al. The relationship between nerve conduction study and clinical grading of carpal tunnel syndrome. J Clin Diagn Res 2016;10:OC13-8.
21. Padua L, Padua R, Aprile I, et al. Italian multicentre study of carpal tunnel syndrome. Differences in the clinical and neurophysiological features between male and female patients. J Hand Surg Br 1999;24:579-82.
22. Bayrak AO, Tilki HE, Coşkun M. Sympathetic skin response and akson count in carpal tunnel syndrome. J Clin Neurophysiol 2007;24:70-5.
23. Koç F, Yerdelen D, Sarıca Y. Motor unit number estimation in cases with carpal tunnel syndrome. Intern J Neuroscience 2006;116:1263-70.
24. Yilmaz O, Sunter G, Salcini C, et al. Motor unit number estimation ıs sensitive in detecting motor nerve ınvolvement in patients with carpal tunnel syndrome. J Clin Neurol 2016;12:166-71.
25. Caetano MR, Aksonal degeneration in association with carpal tunnel syndrome. Arq neuropsiquiatr 2003;61:48-50.