Document Type : Original Article

Author

Department of Neurology, Siirt Training and Research Hospital, 56100, Siirt, Turkey

Abstract

Background: The Martin-Gruber anastomosis (MGA) represents a nerve innervation anomaly in the upper extremity, potentially leading to misinterpretation during standard nerve conduction studies (NCSs). This study aims to characterize the electrophysiological attributes of MGA in both healthy subjects and individuals diagnosed with carpal tunnel syndrome (CTS).
Methods: This case-control study involved the electrophysiological assessment of 506 forearms, segregated into two distinct groups: a CTS positive (+) case group and a CTS negative (-) control group. The evaluations were conducted over an average period of 8 months in the neurophysiology laboratory. The study encompassed 294 forearms from 147 healthy individuals without CTS and 212 forearms from 106 patients diagnosed with CTS, both clinically and electrodiagnostically.
Results: The relationship between the presence of type I MGA and the CTS (+) group was statistically significant (P = 0.002). Similarly, the relationship between the presence of type II MGA and the CTS (+) group was statistically significant (P = 0.013). On the other hand, the relationship between the presence of type III MGA and the CTS (+) group was not statistically significant (P = 0.208). Likewise, the relationship between the presence of type IV MGA and the CTS (+) group was not statistically significant (P = 0.807). The correlation between the side of type I MGA and the groups did not reach statistical significance (P = 0.770). 
The relationship between the side of type II MGA and the groups also did not attain statistical significance (P = 0.990). Similarly, the side of type III MGA and its association with the groups did not yield statistical significance (P = 0.402). Finally, the relationship between the side of type IV MGA and the groups was not statistically significant (P = 0.166).
Conclusion: The MGA represents a relatively frequent anatomical variation observed in the upper extremity. Notably, its presence demonstrated significance in the first dorsal interosseous (FDI) muscle (type II) and the abductor digiti minimi (ADM) muscle (type I) among patients with CTS. The present study emphasizes the importance of recognizing this variation during upper extremity NCSs for a correct diagnostic approach and treatment plan to avoid misdiagnosis of median-ulnar peripheral neuropathy.
 

Keywords

  1. Kaur N, Singla RK, Kullar JS. Martin-Gruber anastomosis- a cadaveric study in North Indian population. J Clin Diagn Res 2016; 10(2): AC09-AC11.
  2. Simon R, Aminoff M, Greenberg D. Clinical Neurology. 4th Stanford, CA: Appleton and Lange; 1999. p. 170-3.
  3. Erdem HR, Ergun S, Erturk C, Ozel S. Electrophysiological evaluation of the incidence of martin-gruber anastomosis in healthy subjects. Yonsei Med J 2002; 43(3): 291-5.
  4. Santoro L, Rosato R, Caruso G. Median-ulnar nerve communications: electrophysiological demonstration of motor and sensory fibre cross-over. J Neurol 1983; 229(4): 227-35.
  5. Iyer V, Fenichel GM. Normal median nerve proximal latency in carpal tunnel syndrome: A clue to coexisting Martin-Gruber anastomosis. J Neurol Neurosurg Psychiatry 1976; 39(5): 449-52.
  6. Simonetti S. Electrophysiological study of forearm sensory fiber crossover in Martin-Gruber anastomosis. Muscle Nerve 2001; 24(3): 380-6.
  7. Oh SJ. Electrophysiology. 3rd Philadelphia, PA: Lippincott Williams & Wilkins; 2003. p. 345-52.
  8. Simonetti S, Krarup C. Unusual ulnar sensory innervation and Martin-Gruber anastomosis in a patient with a carpal tunnel syndrome. J Neurol 2000; 247(2): 141-2.
  9. Oh SJ. Clinical electromyography: Nerve conduction studies. 3rd Philadelphia, PA: Lippincott Williams & Wilkins; 2003. p. 848.
  10. Lee KS, Oh CS, Chung IH, Sunwoo IN. An anatomic study of the Martin-Gruber anastomosis: Electrodiagnostic implications. Muscle Nerve 2005; 31(1): 95-7.
  11. Cho NS, Kim DH, Kim MY, Park BK. Electrophysiological and ultrasonographic findings in ulnar neuropathy with Martin-Gruber anastomosis. Muscle Nerve 2013; 47(4): 604-7.
  12. Burakgazi AZ, Russo M, Bayat E, Richardson PK. Underrecognized anomaly: proximal martin-gruber anastomosis at the elbow. J Clin Neurophysiol 2014; 31(1): 31-4.
  13. Gutmann L. Median--ulnar nerve communications and carpal tunnel syndrome. J Neurol Neurosurg Psychiatry 1977; 40(10): 982-6.
  14. Rubin DI, Dimberg EL. Martin-Gruber anastomosis and carpal tunnel syndrome: [corrected] morphologic clues to identification. Muscle Nerve 2010; 42(3): 457-8.
  15. Kayamori R. Electrodiagnosis in Martin-Gruber anastomosis. Nihon Seikeigeka Gakkai Zasshi 1987; 61(12): 1367-72. [In Japanese].
  16. American Association of Electrodiagnostic Medicine, American Academy of Neurology, and American Academy of Physical Medicine and Rehabilitation. Practice parameter for electrodiagnostic studies in carpal tunnel syndrome: Summary statement. Muscle Nerve 2002; 25(6): 918-22.
  17. Jablecki CK, Andary MT, Floeter MK, Miller RG, Quartly CA, Vennix MJ, et al. Practice parameter: Electrodiagnostic studies in carpal tunnel syndrome. Report of the American Association of Electrodiagnostic Medicine, American Academy of Neurology, and the American Academy of Physical Medicine and Rehabilitation. Neurology 2002; 58(11): 1589-92.
  18. American Association of Electrodiagnostic Medicine. Guidelines in electrodiagnostic medicine. Muscle Nerve 1992; 15(2): 229-53.
  19. Saba EK. Median versus ulnar medial thenar motor recording in diagnosis of carpal tunnel syndrome. Egypt. Rheumatol 2015; 37(3): 139-46.
  20. Preston DC, Shapiro BE. Electromyography and Neuromuscular Disorders: Clinical-electrophysiologic correlations. 3rd London, UK: W.B. Saunders; 2013.
  21. Di Stefano, V, Gagliardo A, Barbone F, Vitale M, Ferri L, Lupica A, et al. Median-to-Ulnar nerve communication in carpal tunnel syndrome: An electrophysiological study. Neurol Int 2021; 13(3): 304-14.
  22. Sarikcioglu L, Sindel M, Ozkaynak S, Aydin H. Median and ulnar nerve communication in the forearm: An anatomical and electrophysiological study. Med Sci Monit 2003; 9(9): BR351-56.
  23. Hasegawa O, Matsumoto S, Iino M, Kirigaya N, Mimura E, Wada N, et al. Prevalence of Martin-Gruber anastomosis on motor nerve conduction studies. No To Shinkei 2001; 53(2): 161-4. [In Japanese].
  24. Kimura J, Murphy MJ, Varda DJ. Electrophysiological study of anomalous innervation of intrinsic hand muscles. Arch Neurol 1976; 33(12): 842-4.
  25. Amoiridis G. Frequency of ulnar-to-median nerve anastomosis. Electromyogr Clin Neurophysiol 1992; 32(4-5): 255-6.
  26. Prates LC, de Carvalho VC, Prates JC, Langone F, Esquisatto MAM. The Martin-Gruber anastomosis in Brazilians: An anatomical study. Braz J Morphol Sci 2017; 20(3): 177-80.
  27. de Almeida JA, Vitti M, Garbino JA. Anatomical study of the Martin-Gruber anastomosis. Hansen Int 1999; 24(1): 15-20. [In Portuguese].
  28. Felippe MM, Telles FL, Soares ACL, Felippe FM. Anastomosis between median nerve and ulnar nerve in the forearm. J. Morphol Sci 2012; 29(1): 23-6.
  29. Kazakos KJ, Smyrnis A, Xarchas KC, Dimitrakopoulou A, Verettas DA. Anastomosis between the median and ulnar nerve in the forearm. An anatomic study and literature review. Acta Orthop Belg 2005; 71(1): 29-35.
  30. Rodriguez-Niedenfuhr M, Vazquez T, Parkin I, Logan B, Sanudo JR. Martin-Gruber anastomosis revisited. Clin Anat 2002; 15(2): 129-34.
  31. Shu HS, Chantelot C, Oberlin C, Alnot JY, Shao H. Martin-Gruber communicating branch: anatomical and histological study. Surg Radiol Anat 1999; 21(2): 115-8.
  32. Nakashima T. An anatomic study on the Martin-Gruber anastomosis. Surg Radiol Anat 1993; 15(3): 193-5.
  33. Uchida Y, Sugioka Y. Electrodiagnosis of Martin-Gruber connection and its clinical importance in peripheral nerve surgery. J Hand Surg Am 1992; 17(1): 54-9.
  34. Thomson A. Third Annual Report of Committee of Collective Investigation of Anatomical Society of Great Britain and Ireland for the Year 1891-92. J Anat Physiol 1893; 27(Pt 2): 183-94.
  35. Gruber W. Ueber die verbindung des nervus medianus mit dem nervus ulnaris am unterarme des menshen und der saugethiere. Arch Anat Phisiol 1870; 37: 501-22. [In German].
  36. Oh SJ. Clinical electromyography: Nerve conduction studies. 2nd Philadelphia, PA: Lippincott Williams & Wilkins; 1993. p. 314-33.
  37. Taams KO. Martin-Gruber connections in South Africa. An anatomical study. J Hand Surg Br 1997; 22(3): 328-30.
  38. Wilbourn A, Lambert E. The forearm median-to-ulnar nerve communication: electrodiagnostic aspects. Neurology 1976; 26: 368.
  39. Khosrawi S, Kianimehr L, Andalib S. The prevalence of Martin-Gruber anastomosis in Iranian subjects by electrodiagnostic criteria. Iran J Neurol 2015; 14(4): 231-2.
  40. Roy J, Henry BM, PEkala PA, Vikse J, Saganiak K, Walocha JA, et al. Median and ulnar nerve anastomoses in the upper limb: A meta-analysis. Muscle Nerve 2016; 54(1): 36-47.