title: Electrophysiologic correlates of weakness in L5/S1 radiculopathy.
abstract: BACKGROUND
  Management of patients with radiculopathy involves estimating the degree of physiologic and anatomic injury, and weighing that to predict the likely clinical course.
  
  
  OBJECTIVE
  To determine whether low distal peroneal and tibial CMAP amplitudes correlate with weakness and fibrillations of functionally relevant muscles in L5/S1 radiculopathy (LSR).
  
  
  METHODS
  We reviewed clinical and electrophysiologic data in 66 consecutive patients with LSR.
  
  
  RESULTS
  A significantly greater number of patients with low peroneal CMAP amplitudes had weakness of L5 (p = 0.025) and S1 innervated leg muscles (p < 0.001). Low tibial CMAP amplitudes were also associated with weakness of S1 innervated muscles (p < 0.038). The association of low peroneal CMAP amplitudes with weakness persisted when weakness of at least 3 muscles was considered in the analysis for L5 (p < 0.0001) and S1 (p = 0.014) innervated muscles.
  
  
  CONCLUSIONS
  Low peroneal and tibial CMAP amplitudes may serve as surrogate measures for segmental weakness of functionally relevant muscles in LSR.
authors.affiliation: Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, Beth Israel Medical Center. SScelsa@BethIsraelNY.org
authors.forename: S N
authors.initials: SN
authors.lastname: Scelsa
authors.forename: A R
authors.initials: AR
authors.lastname: Berger
authors.forename: S
authors.initials: S
authors.lastname: Herskovitz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004568:Electrodiagnosis; D004576:Electromyography; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000175:diagnosis / Q000503:physiopathology; D008159:Lumbar Vertebrae / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology; D018908:Muscle Weakness / Q000175:diagnosis / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000294:innervation; D009431:Neural Conduction / Q000502:physiology; D010543:Peroneal Nerve / Q000503:physiopathology; D011843:Radiculopathy / Q000175:diagnosis / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D012189:Retrospective Studies; D012447:Sacrum / Q000503:physiopathology; D013167:Spondylitis, Ankylosing / Q000175:diagnosis / Q000503:physiopathology; D013979:Tibial Nerve / Q000503:physiopathology