Comparison of surgical and electrodiagnostic findings in single root lumbosacral radiculopathies

Muscle Nerve. 2003 Jan;27(1):60-4. doi: 10.1002/mus.10291.


To identify the segmental innervation of L-2-S-1 muscles, we compared the preoperative electrodiagnostic examinations of 45 patients with single-level lumbosacral radiculopathies confirmed radiologically and surgically. The electrodiagnostic findings were classified as abnormal only by the needle examination and only if muscles demonstrated active denervation or a marked neurogenic motor unit potential firing pattern. In comparison to other surgical, intraoperative root stimulation, and clinical studies, we found several differences. Overall, there was little overlap among L-2-4, L-5, and S-1 radiculopathies. The tibialis anterior was predominantly L-5 innervated, the gastrocnemius (medial and lateral head) predominantly S-1 innervated, and the biceps femoris (short and long head) exclusively S-1 innervated. The two heads of biceps femoris were not affected in any patients with L-5 radiculopathy in whom they were examined. These findings help guide both the clinician and surgeon in the diagnosis and treatment of lumbosacral radiculopathies.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Electromyography*
  • Female
  • Humans
  • Lumbar Vertebrae
  • Lumbosacral Region / innervation
  • Male
  • Middle Aged
  • Muscle, Skeletal / innervation
  • Radiculopathy / diagnosis*
  • Radiculopathy / surgery*