title: Histopathology of the filum terminale in children with and without tethered cord syndrome with attention to the elastic tissue within the filum.
abstract: OBJECTIVE
  To compare histologically transected fila from pediatric patients with tethered cord syndrome (TCS), with and without a low conus, with controls, focusing on collagenous and elastic tissue.
  
  
  METHODS
  Thirty fila from patients with TCS, including 5 where minimal cautery was used prior to filum section, were compared with fila from 27 pediatric cadavers without TCS (controls). Sections of fila were stained with H&E, Masson trichrome and Verhoeff von Gieson elastic stains, and 7 with Gordon and Sweet's reticulin stain.
  
  
  RESULTS
  Fila from controls showed loose fibrous connective tissue (FCT) with thin and evenly dispersed elastic fibers (EFs). Reticulin fibers (RFs) were seen in blood vessel walls and nerve twigs. Fat was identified microscopically in 2 fila. All fila from patients with TCS had dense FCT. The EFs were in normal numbers in 17, and focally or diffusely decreased in 13. All 25 patients where the fila were cauterized during resection had thick and coiled EFs. Coiling was not seen when minimal cautery was applied. RFs were seen in blood vessel walls and nerve twigs. Fat was identified in 19 patients. Findings were similar, whether the conus termination was normal or low.
  
  
  CONCLUSIONS
  The fila of all patients with TCS, whether or not the conus was low, showed abnormal FCT. EFs were decreased in 48 % of patients; however, there were thick and coiled EFs in all patients. Coiling of EFs, initially thought to be an abnormality in patients, is considered most likely to be a result of cautery (i.e., artifactual/iatrogenic coiling).
authors.affiliation: Division of Anatomic Pathology, Department of Pathology and Laboratory Medicine, British Columbia Children's Hospital, 4500 Oak Street, Vancouver, British Columbia, V6H 3N1, Canada. ghendson@cw.bc.ca.
authors.forename: Glenda
authors.initials: G
authors.lastname: Hendson
authors.affiliation: Division of Anatomic Pathology, Department of Pathology and Laboratory Medicine, British Columbia Children's Hospital, 4500 Oak Street, Vancouver, British Columbia, V6H 3N1, Canada.
authors.forename: Christopher
authors.initials: C
authors.lastname: Dunham
authors.affiliation: Division of Neurosurgery, Department of Surgery, British Columbia Children's Hospital, Vancouver, British Columbia, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Steinbok
mesh_terms: D000293:Adolescent; D001288:Attention; D002420:Cauda Equina / Q000000981:diagnostic imaging / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D003238:Connective Tissue / Q000000981:diagnostic imaging / Q000473:pathology*; D004547:Elastic Tissue / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009436:Neural Tube Defects / Q000000981:diagnostic imaging / Q000473:pathology*
keywords: Cautery; Fibrous connective tissue; Occult tethered cord; Reticulin