title: A comparative study for wide excision of malignant tumors distal to S2.
abstract: OBJECTIVE
  We conducted a retrospective study comparing 5 patients (Group A) who underwent posterior excision of tumors distal to S2 using a modified threadwire saw (MT-saw) with 5 similar patients (Group B) who underwent tumor excision using chisels and airtomes.
  
  
  METHODS
  The data of 10 patients were obtained from intra-operative records. A flexible silver guide probe connected to an MT-saw by a suture thread was devised for use in osteotomy passing through the S1 sacral canal in the lateral sacrum. Operative time, blood loss and excisional margins were compared between the two groups.
  
  
  RESULTS
  Group A had a shorter average operative time (2 hours 24 minutes) and smaller average blood loss (2,124.6 ml) than Group B. In Group A, one patient incurred an S1 nerve root injury, and all patients had wide histological margins. In Group B, one patient had an S1 nerve root injury and another tumor contamination due to a fracture.
  
  
  CONCLUSIONS
  The MT-saw greatly facilitated lateral sacral osteotomy and reduced the risk of tumor cell spread, permitting faster, safer excision with a wider margin.
authors.affiliation: Department of Orthopaedic Surgery, Nihon University School of Medicine, 30-1 Oyaguchi-kamimachi, Itabashi-ku, Tokyo 173-8610, Japan. sosaka@med.nihon-u.ac.jp
authors.forename: Shunzo
authors.initials: S
authors.lastname: Osaka
authors.forename: Hiromi
authors.initials: H
authors.lastname: Matsuzaki
authors.forename: Eiji
authors.initials: E
authors.lastname: Osaka
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Junnosuke
authors.initials: J
authors.lastname: Ryu
mesh_terms: D000328:Adult; D000368:Aged; D002817:Chordoma / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods; D012189:Retrospective Studies; D012447:Sacrum / Q000473:pathology / Q000601:surgery; D013125:Spinal Neoplasms / Q000473:pathology / Q000601:surgery*