title: Unusual association of ankylosing spondylitis with congenital spinal deformity.
abstract: METHODS
  In all, 4 cases of the coexistence of congenital spinal deformity (CSD) and ankylosing spondylitis (AS) were reviewed.
  
  
  OBJECTIVE
  To provide an insight into the unusual association between CSD and AS.
  
  
  BACKGROUND
  CSD combined with musculoskeletal anomalies, including clubfeet, Sprengel deformity, Klippel-Feil syndrome, and developmental dysplasia of the hip, has been described in the literature. Additionally, the rare coexistence between AS and other inflammatory joint diseases, such as systemic lupus erythematosus, mixed connective tissue disease, or Behçet disease, has also been reported. However, to the authors' knowledge, the coexistence of CSD and AS has not been described in the literature.
  
  
  METHODS
  In all, 4 patients presented with symptoms of lower back pain for at least 1 year. Among them, 3 patients (cases 1, 2, and 3) were initially diagnosed as CSD, and classified as butterfly vertebra in 2 patients (case 1, case 3), incarcerated hemivertebra in 1 patient (case 2). Furthermore, a diagnosis of coexistence of CSD and AS was proposed in these 3 cases with a delay in the diagnosis of AS for 1 to 10 years. The fourth patient sought initial medical attention in our hospital without delay in diagnosis. In case 1, polysegmental Smith-Petersen osteotomy and transpedicular fixation were performed, and drugs were administrated. Case 2, case 3, and case 4 were treated with amethopterin, folic acid, salicylazosulfapyridine, and celecoxib.
  
  
  RESULTS
  At the latest follow-up, 4 patients had no back pain and were satisfied with the outcome.
  
  
  CONCLUSIONS
  The coexistence of CSD and AS is very rare. However, it is necessary to consider the diagnosis of AS in CSD patients who present with symptoms such as inflammatory low back pain, morning stiffness, loss of global sagittal balance, and other clinical features can not be exclusively explained by CSD solely.
authors.affiliation: Spine Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China.
authors.forename: Bang-ping
authors.initials: BP
authors.lastname: Qian
authors.forename: Yong
authors.initials: Y
authors.lastname: Qiu
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.forename: Ze-zhang
authors.initials: ZZ
authors.lastname: Zhu
authors.forename: Wei-jun
authors.initials: WJ
authors.lastname: Wang
authors.forename: Wei-wei
authors.initials: WW
authors.lastname: Ma
mesh_terms: D000328:Adult; D006801:Humans; D008159:Lumbar Vertebrae / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D010027:Osteotomy; D011859:Radiography; D013167:Spondylitis, Ankylosing / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D013904:Thoracic Vertebrae / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000601:surgery; D016896:Treatment Outcome