title: Ten percent of patients with adolescent idiopathic scoliosis have variations in the number of thoracic or lumbar vertebrae.
abstract: BACKGROUND
  Surveys have demonstrated that wrong-site surgery of the spine is performed by up to 50% of spine surgeons over the course of a career. Inaccurate identification of appropriate vertebral levels is a common reason for wrong-site spine surgery. The present study examined the prevalence of variations in the number of vertebrae in patients with adolescent idiopathic scoliosis.
  
  
  METHODS
  A retrospective review of radiographs and reports of 364 consecutive patients undergoing operative treatment for adolescent idiopathic scoliosis at a single center was performed. The study included eighty-eight male patients (24%) and 276 female patients (76%) with a mean age of fourteen years (range, ten to twenty years). Radiographs were reviewed to assess the number of thoracic and lumbar vertebrae and the presence of a lumbosacral transitional vertebra.
  
  
  RESULTS
  Ten percent of the patients (thirty-eight) had an atypical number of vertebrae in the thoracic and/or lumbar spine. Twenty-one patients (5.8%) had an atypical number of thoracic vertebrae, with fourteen having eleven thoracic vertebrae and seven patients having thirteen. Twenty-four patients (6.6%) had an atypical number of lumbar vertebrae, with four having four lumbar vertebrae and twenty patients having six. A lumbosacral transitional vertebra was present in 6.3% (twenty-three) of the patients. Multilevel vertebral anomalies were present in 1.9% of the patients (seven of 364). A variation in the number of vertebrae had been identified in 0.5% (two) of the reports by the radiologist.
  
  
  CONCLUSIONS
  Variations in the number of thoracic or lumbar vertebrae were found in 10% of patients with adolescent idiopathic scoliosis but had been identified in only 0.5% of the radiology reports.
authors: Children's Orthopaedic Center, Children's Hospital Los Angeles, 4650 Sunset Boulevard, Los Angeles, CA 90027, USA.
authors: David A
authors: DA
authors: Ibrahim
authors: Karen S
authors: KS
authors: Myung
authors: David L
authors: DL
authors: Skaggs
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000002:abnormalities* / Q000000981:diagnostic imaging; D008297:Male; D019300:Medical Errors / Q000517:prevention & control; D011859:Radiography; D012189:Retrospective Studies; D012600:Scoliosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D013904:Thoracic Vertebrae / Q000002:abnormalities* / Q000000981:diagnostic imaging; D055815:Young Adult