SEVERE AND EXTREME IDIOPATHIC MEDIAN NERVE LESIONS AT THE WRIST: NEW INSIGHTS INTO ELECTRODIAGNOSTIC PATTERNS AND REVIEW OF THE LITERATURE PAUL SEROR, MD,1 and RAPHAELE SEROR, MD, PhD 1 2
2
Laboratoire d’electromyographie, Avenue Ledru Rollin, 75011 Paris, France Assistance Publique H^ opitaux de Paris, H^ opital Bic^ etre, Department of Rheumatology, Le Kremlin Bic^ etre, France
Accepted 13 May 2014 ABSTRACT: Introduction: We evaluated the electrodiagnostic (EDX) pattern of severe and extreme median nerve lesions at the wrist (MNLW) in patients with idiopathic carpal tunnel syndrome. Methods: EDX data were recorded in 229 patients with 314 severe and extreme MNLW and 447 patients with 777 nonsevere MNLW. We recorded distal motor latency (DML) to abductor pollicis brevis (APB) and second lumbricalis (2L), sensory conduction (SC) from digits 2 and 3, and needle examination of APB. Results: Preservation rate of DML to APB and 2L and of SC from digits 2 and 3 were 100%, 100%, 85%, and 76%, respectively, for severe MNLW, and 37%, 90%, 36%, and 26% for extreme MNLW. Active denervation, as demonstrated by fibrillation potentials, was found in 1% of non-severe NMLW, 7% of severe MNLW, and 56% of extreme MNLW cases. Conclusions: In idiopathic severe and extreme MNLW, the DML to the 2L and averaged SC from digit 2 can be present when other responses are absent. Muscle Nerve 51: 201–206, 2015
Few studies have reported severe and extreme median nerve lesions at the wrist (MNLW) (Table S1, refer to Supplementary Material available online).1–8 Some have reported data on nerve conduction studies, but fewer have reported needle electrode examination findings. Electrodiagnosis (EDX), including nerve conduction studies and needle examination, is the reference standard examination for diagnosis of carpal tunnel syndrome (CTS) and for evaluation of severity (axonal loss and active denervation). In all previous studies but 1,8 the sensory nerve action potential (SNAP) of the median nerve was found to disappear far earlier than the compound muscle action potential (CMAP) of the abductor pollicis brevis (APB), and the second lumbricalis (2L) CMAP may be preserved longer than that of the APB. Are severe and extreme MNLW characterized by specific electrodiagnostic patterns? To Additional Supporting Information may be found in the online version of this article. Abbreviations: 2L, second lumbricalis; APB, abductor pollicis brevis; CMAP, compound muscle action potential; CTS, carpal tunnel syndrome; DML, distal motor latency; EDX, electrodiagnosis or electrodiagnostic; MNLW, median nerve lesions at the wrist; OSCV, orthodromic sensory conduction velocity; SC, sensory conduction; SNAP, sensory nerve action potential Key words: abductor pollicis brevis; body mass index; carpal tunnel syndrome; motor conduction; second lumbricalis; sensory conduction Correspondence to: P. Seror; e-mail: [email protected] C 2014 Wiley Periodicals, Inc. V
Published online 15 May 2014 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/mus.24288
Median Nerve Wrist Lesions
address these diagnostic issues we prospectively investigated a large series of severe and extreme MNLW, compared findings with those for nonsevere MNLW, and reviewed the literature to propose recommendations for evaluating severe and extreme MNLW. METHODS Patients. We collected data prospectively from successive patients with classic or probable CTS referred to our 2 electrodiagnostic laboratories, 1 in Paris and 1 in an industrial eastern suburb, from 2006 to 2007. We further collected all successive cases of patients with severe MNLW up to mid2010 to increase the number of cases and to obtain a ratio of 1 severe to 2 non-severe cases. All clinical and EDX examinations were performed by 1 of the 2 investigators (P.S.) using the same protocol. All patients had clinical symptoms and signs of CTS, with EDX-confirmed MNLW. Clinical CTS criteria may be thenar muscle atrophy or weakness and permanent or intermittent symptoms of burning, tingling, hypesthesia, and paresthesia in the radial 3.5 digits (or of the whole hand), especially at night or on awakening. Our study excluded patients with polyneuropathic features, diabetes mellitus, severe chronic renal failure on dialysis, pregnancy, hypothyroidism, rheumatoid arthritis, wrist osteoarthritis, previous wrist fracture, multiple diseases, and permanent disability. All subjects gave informed consent for use of their data. The study was approved by the local committee on research ethics of Salpetrie`re Hospital. Epidemiologic Evaluation. Epidemiologic assessment included age, gender, height, weight, body mass index (BMI), occupational activity, and frequency of bilateral MNLW. Occupational activity was related to the intensity of occupational hand workload at the job and was stratified into 3 categories: (1) retiree, housewife, or unemployed (at least 6 months); (2) white-collar and computer users; and (3) blue-collar or manual workers. Electrophysiologic Evaluation. Electrophysiology included bilateral nerve conduction study of the median and ulnar nerves and needle examination of MUSCLE & NERVE
February 2015
201
1 muscle per myotome from C6 to C8 (biceps brachii, triceps brachii, first dorsal interosseous muscles) in the more symptomatic upper limb and both APBs. Skin temperature was measured, and hands were warmed prior to testing when it was
2
Laboratoire d’electromyographie, Avenue Ledru Rollin, 75011 Paris, France Assistance Publique H^ opitaux de Paris, H^ opital Bic^ etre, Department of Rheumatology, Le Kremlin Bic^ etre, France
Accepted 13 May 2014 ABSTRACT: Introduction: We evaluated the electrodiagnostic (EDX) pattern of severe and extreme median nerve lesions at the wrist (MNLW) in patients with idiopathic carpal tunnel syndrome. Methods: EDX data were recorded in 229 patients with 314 severe and extreme MNLW and 447 patients with 777 nonsevere MNLW. We recorded distal motor latency (DML) to abductor pollicis brevis (APB) and second lumbricalis (2L), sensory conduction (SC) from digits 2 and 3, and needle examination of APB. Results: Preservation rate of DML to APB and 2L and of SC from digits 2 and 3 were 100%, 100%, 85%, and 76%, respectively, for severe MNLW, and 37%, 90%, 36%, and 26% for extreme MNLW. Active denervation, as demonstrated by fibrillation potentials, was found in 1% of non-severe NMLW, 7% of severe MNLW, and 56% of extreme MNLW cases. Conclusions: In idiopathic severe and extreme MNLW, the DML to the 2L and averaged SC from digit 2 can be present when other responses are absent. Muscle Nerve 51: 201–206, 2015
Few studies have reported severe and extreme median nerve lesions at the wrist (MNLW) (Table S1, refer to Supplementary Material available online).1–8 Some have reported data on nerve conduction studies, but fewer have reported needle electrode examination findings. Electrodiagnosis (EDX), including nerve conduction studies and needle examination, is the reference standard examination for diagnosis of carpal tunnel syndrome (CTS) and for evaluation of severity (axonal loss and active denervation). In all previous studies but 1,8 the sensory nerve action potential (SNAP) of the median nerve was found to disappear far earlier than the compound muscle action potential (CMAP) of the abductor pollicis brevis (APB), and the second lumbricalis (2L) CMAP may be preserved longer than that of the APB. Are severe and extreme MNLW characterized by specific electrodiagnostic patterns? To Additional Supporting Information may be found in the online version of this article. Abbreviations: 2L, second lumbricalis; APB, abductor pollicis brevis; CMAP, compound muscle action potential; CTS, carpal tunnel syndrome; DML, distal motor latency; EDX, electrodiagnosis or electrodiagnostic; MNLW, median nerve lesions at the wrist; OSCV, orthodromic sensory conduction velocity; SC, sensory conduction; SNAP, sensory nerve action potential Key words: abductor pollicis brevis; body mass index; carpal tunnel syndrome; motor conduction; second lumbricalis; sensory conduction Correspondence to: P. Seror; e-mail: [email protected] C 2014 Wiley Periodicals, Inc. V
Published online 15 May 2014 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/mus.24288
Median Nerve Wrist Lesions
address these diagnostic issues we prospectively investigated a large series of severe and extreme MNLW, compared findings with those for nonsevere MNLW, and reviewed the literature to propose recommendations for evaluating severe and extreme MNLW. METHODS Patients. We collected data prospectively from successive patients with classic or probable CTS referred to our 2 electrodiagnostic laboratories, 1 in Paris and 1 in an industrial eastern suburb, from 2006 to 2007. We further collected all successive cases of patients with severe MNLW up to mid2010 to increase the number of cases and to obtain a ratio of 1 severe to 2 non-severe cases. All clinical and EDX examinations were performed by 1 of the 2 investigators (P.S.) using the same protocol. All patients had clinical symptoms and signs of CTS, with EDX-confirmed MNLW. Clinical CTS criteria may be thenar muscle atrophy or weakness and permanent or intermittent symptoms of burning, tingling, hypesthesia, and paresthesia in the radial 3.5 digits (or of the whole hand), especially at night or on awakening. Our study excluded patients with polyneuropathic features, diabetes mellitus, severe chronic renal failure on dialysis, pregnancy, hypothyroidism, rheumatoid arthritis, wrist osteoarthritis, previous wrist fracture, multiple diseases, and permanent disability. All subjects gave informed consent for use of their data. The study was approved by the local committee on research ethics of Salpetrie`re Hospital. Epidemiologic Evaluation. Epidemiologic assessment included age, gender, height, weight, body mass index (BMI), occupational activity, and frequency of bilateral MNLW. Occupational activity was related to the intensity of occupational hand workload at the job and was stratified into 3 categories: (1) retiree, housewife, or unemployed (at least 6 months); (2) white-collar and computer users; and (3) blue-collar or manual workers. Electrophysiologic Evaluation. Electrophysiology included bilateral nerve conduction study of the median and ulnar nerves and needle examination of MUSCLE & NERVE
February 2015
201
1 muscle per myotome from C6 to C8 (biceps brachii, triceps brachii, first dorsal interosseous muscles) in the more symptomatic upper limb and both APBs. Skin temperature was measured, and hands were warmed prior to testing when it was
