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Evaluating The Accuracy of Electrodiagnostic Study in Detecting Suprascapular Neuropathy in Cases of Chronic Shoulder Pain


Samar Gaber Soliman
Dina Mamdoh Serag
Hager Abd-Elmegeed Elaraby
Mohamed M. El-Ghanam
Dalia Salah Saif

Abstract

Background: Electrophysiological study involving electromyography (EMG) and nerve conduction studies are important tools for  diagnosis of entrapment neuropathy, as it had a great role in determining the etiology, and severity of entrapment, confirming the  diagnosis, detecting the site, quantifying the degree of compression as well as documenting the progression and prognosis of the  disorder.


Objectives: To assess the accuracy of electrophysiological studies in diagnosing suprascapular neuropathy in cases of chronic shoulder pain.


Patients and Methods: A controlled randomized prospective study was carried out on 180 patients with chronic shoulder pain. They  were recruited from outpatient clinics of rheumatology, physical medicine, and rehabilitation at our university. Electrophysiological study  regarding nerve conduction study (NCS) of both suprascapular nerves and EMG study to the supraspinatus and infraspinatus muscles  were carried out.


Results: Approximately 11.1% of patients of the current study were diagnosed as suprascapular neuropathy regarding abnormal motor  nerve conduction study results, and 9.4% of patients were diagnosed based on abnormal electromyographic findings. The latency and  amplitude of suprascapular nerve on motor nerve conductive (MNC) at cutoff value of >2.35, and <6.95 had accuracy of 69.1%, and 66.7%  to detect the occurrence of suprascapular neuropathy. The duration, and amplitude of supraspinatus MUAP on EMG at cutoff value of  >5.85, and <1.175 had an accuracy of 74.7%, and 74%, also, the duration, of infraspinatus MUAP on EMG at cutoff value of >6.1 had 79% accuracy, that means at those points, we could differentiate between the affected and non-affected suprascapular nerve. 


Conclusion:  Electrophysiological study involving electromyography (EMG), and nerve conduction studies is an important and accurate tool for  diagnosing suprascapular neuropathy in cases of chronic shoulder pain, with accurate and precise cutoff points, in addition to clinical  examination and radiological findings. 


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eISSN: 2090-7125
print ISSN: 1687-2002