title: Innervation of "painful" lumbar discs.
abstract: METHODS
  The authors investigated the innervation of discographically confirmed degenerated and "painful" human intervertebral discs.
  
  
  OBJECTIVE
  To determine the type and distribution patterns of nerve fibers present in degenerated human intervertebral discs.
  
  
  BACKGROUND
  The innervation of intervertebral discs has previously been extensively described in fetal and adult animals as well as humans. However, little is yet known about the innervation of severely degenerated human lumbar discs. The question may be posed whether a disc that has been removed for low back pain possesses an increased innervation compared with normal discs.
  
  
  METHODS
  The presence of nerve fibers was investigated using acetylcholinesterase enzyme histochemistry, as well as neurofilament and substance P immunocytochemistry. From 10 degenerated and 2 control discs, the anterior segments were excised and their nerve distribution studied by examining sequential sections.
  
  
  RESULTS
  In all specimens, nerve fibers of different diameters were found in the anterior longitudinal ligament and in the outer region of the disc. In 8 of 10 degenerated discs, fibers were also found in the inner parts of the disc. Substance P-immunoreactive nerve fibers were sporadically observed in the anterior longitudinal ligament and the outer zone of the anulus fibrosus.
  
  
  CONCLUSIONS
  Findings indicate a more extensive disc innervation in the severely degenerated human lumbar disc compared with normal discs. The nociceptive properties of at least some of these nerves are highly suggested by their substance P immunoreactivity, which provides further evidence for the existence of a morphologic substrate of discogenic pain.
authors.affiliation: Department of Neurosurgery, Groningen University, The Netherlands.
authors.forename: M H
authors.initials: MH
authors.lastname: Coppes
authors.forename: E
authors.initials: E
authors.lastname: Marani
authors.forename: R T
authors.initials: RT
authors.lastname: Thomeer
authors.forename: G J
authors.initials: GJ
authors.lastname: Groen
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis; D000328:Adult; D001808:Blood Vessels / Q000473:pathology; D004268:DNA-Binding Proteins / Q000032:analysis; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007403:Intervertebral Disc / Q000737:chemistry / Q000294:innervation* / Q000473:pathology; D007405:Intervertebral Disc Displacement / Q000473:pathology*; D017116:Low Back Pain / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000033:anatomy & histology* / Q000601:surgery; D008297:Male; D008465:Mechanoreceptors / Q000276:immunology / Q000473:pathology; D008875:Middle Aged; D050778:NFATC Transcription Factors; D009413:Nerve Fibers, Myelinated / Q000737:chemistry / Q000473:pathology; D009687:Nuclear Proteins / Q000032:analysis; D013373:Substance P / Q000032:analysis; D014157:Transcription Factors / Q000032:analysis
chemical_list: D004268:DNA-Binding Proteins; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D014157:Transcription Factors; D013373:Substance P; D000110:Acetylcholinesterase