title: Tumor Occupation in the Spinal Canal and Clinical Symptoms of Cauda Equina Schwannoma: An Analysis of 22 Cases.
abstract: METHODS
  Retrospective, radiological study.
  
  
  OBJECTIVE
  To determine the relationship between clinical symptoms and the extent of tumor occupation of the spinal canal by cauda equina schwannoma.
  
  
  BACKGROUND
  Little is known about the relationship between the size of tumors of the cauda equina and the manifestation of clinical symptoms. We analyzed this relationship by estimating the percentage of tumor occupation (PTO) in the spinal canal in cauda equina schwannomas and by correlating this parameter with the presence and severity of clinical symptoms.
  
  
  METHODS
  Twenty-two patients (9 men and 13 women; age, 19-79 years; mean age, 55.3 years) who were radiologically diagnosed with schwannomas of the cauda equina between April 2004 and July 2014 were retrospectively analyzed. PTO was measured in axial and sagittal magnetic resonance imaging slices in which the cross-sectional area of the tumor was the largest. Data regarding clinical symptoms and results of physical examinations were collected from patient medical records. PTO differences between symptom-positive and -negative groups were analyzed for each variable.
  
  
  RESULTS
  In the 4 cases in which tumor presence was not related to clinical symptoms, PTO was 5%-10% (mean, 9%) in axial slices and 23%-31% (mean, 30%) in sagittal slices. In the 18 cases in which symptoms were associated with the tumor, PTO was 11%-86% (mean, 50%) in axial slices and 43%-88% (mean, 71%) in sagittal slices. PTO in axial slices was significantly higher in the presence of Déjèrine symptoms and/or muscle weakness, a positive straight leg raise test, and a positive Kemp sign.
  
  
  CONCLUSIONS
  PTO >20% in axial slices and >40% in sagittal slices can be an indication of symptomatic cauda equina schwannoma.
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Fujii
authors.affiliation: Department of Rehabilitation, Tsukuba Gakuen Hospital, Tsukuba, Japan.
authors.forename: Masataka
authors.initials: M
authors.lastname: Sakane
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Abe
authors.affiliation: Department of Orthopaedic Surgery, Kensei General Hospital, Sakuragawa, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Nakagawa
authors.affiliation: Department of Orthopaedic Surgery, Tokyo Medical University Ibaraki Medical Center, Inashiki, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Sakai
authors.affiliation: Department of Orthopaedic Surgery, Mito Kyodo General Hospital, Mito, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Tatsumura
authors.affiliation: Department of Orthopaedic Surgery, Kenpoku Medical Center Takahagi Kyodo Hospital, Takahagi, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Funayama
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Yamazaki
keywords: Cauda equina; Neurilemmoma; Surgery