title: Characteristics of lumbar spondylolysis in elementary school age children.
abstract: OBJECTIVE
  Lumbar spondylolysis, a stress fracture of the pars interarticularis in the lumbar spine, is often precipitated by trauma, but there may be a congenital predisposition to this condition. There have been few studies on spondylolysis in young children, despite their suitability for studies on congenital defects. The aim of this study was to identify the clinical features of lumbar spondylolysis in elementary school age children in order to elucidate its pathogenesis.
  
  
  METHODS
  Thirty lumbar spondylolysis patients (23 boys, 7 girls, including a pair of twins; mean age 9.5 years, age range 5-12 years) were studied. Patient data on history of athletic activity, symptoms at first consultation, and radiological findings such as spinal level, stage of the stress fracture, and skeletal age were collected.
  
  
  RESULTS
  Among the 30 patients, 27 (21 boys, 6 girls) had L5 spondylolysis (90.0 %). Only 2 patients had no history of athletic activity at the first consultation. All patients, except for 2 whose diagnosis was incidental, complained of low back pain. In the 27 patients with L5 spondylolysis, 17 (63.0 %) had terminal-stage fracture and 25 (92.6 %) had spina bifida occulta (SBO) involving the S1 lamina. Sixteen of the 27 (59.3 %) had SBO involving the affected lamina (L5) and S1 lamina. In contrast, the 3 patients with L3 or L4 spondylolysis had no evidence of SBO. With respect to skeletal age, 23 of the 27 L5 spondylolysis patients (85.2 %) were in the cartilaginous stage while the remaining 4 patients were in the apophyseal stage.
  
  
  CONCLUSIONS
  Lumbar spondylolysis in elementary school age children was commonly a terminal-stage bone defect at L5, which was not necessarily related to history of athletic activity and was sometimes asymptomatic. It was often associated with SBO, indicating a possible congenital predisposition. These findings may provide further insight into the pathogenesis of lumbar spondylolysis.
authors.affiliation: Department of Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan. norinoridowluck@yahoo.co.jp.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Sakai
authors.affiliation: Department of Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Goda
authors.affiliation: Department of Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Fumitake
authors.initials: F
authors.lastname: Tezuka
authors.affiliation: Department of Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Takata
authors.affiliation: Department of Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Kosaku
authors.initials: K
authors.lastname: Higashino
authors.affiliation: Hachioji Sports Clinic, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sato
authors.affiliation: Hachioji Sports Clinic, Tokyo, Japan.
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Mase
authors.affiliation: Department of Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nagamachi
authors.affiliation: Department of Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Sairyo
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000209:etiology; D008159:Lumbar Vertebrae / Q000473:pathology; D008161:Lumbosacral Region / Q000473:pathology; D008297:Male; D012307:Risk Factors; D012727:Sex Characteristics; D016136:Spina Bifida Occulta / Q000150:complications; D013169:Spondylolysis / Q000209:etiology* / Q000473:pathology; D013177:Sports
keywords: Children; Elementary school; Immature spine; Lumbar spondylolysis; Skeletal age