title: The ATA and its surgical importance: a newly described ligament lying between the dural sac and the ligamentum flavum at the L5 level.
abstract: METHODS
  The anatomy of a new ligament in the human spine the ATA is described.
  
  
  OBJECTIVE
  To describe a new ligament; the ATA, which lies between the dural sac and the ligamentum flavum at the L5 level and to discuss it's surgical importance.
  
  
  BACKGROUND
  Postoperative cerebrospinal fluid (CSF) leakage translates into longer hospital stays with significant implications for the patient, the health care system, and society as a whole. To avoid injury to the dural sac during lumbar surgery, it is crucial to know the surgical anatomy and its variations.
  
  
  METHODS
  The length and the number of ATAs were examined in 14 consecutive patients, which underwent an L5 laminoflavectomy in our department. The ATA and its anatomic landmarks are described here for the first time in the literature. We named this ligament the ATA; reminding us to pay attention to the Terminal Attachment.
  
  
  RESULTS
  The presence of the ATA is demonstrated in 10 patients (71%). There was a double ATA in four patients (40%). The mean length of the ATA was 7.7 ± 1.8 mm. The ATA originates from the dorsal surface of the dura mater at the level of the superior border of the superior facet of the S1 vertebra and projects toward the ligamentum flavum. Histologic examination of the ATA revealed fibrous connective tissue.
  
  
  CONCLUSIONS
  In this preliminary study, we have described a new ligament, the ATA, between the dural sac and the ligamentum flavum at the L5 level. The ATA is an important structure that creates a potential risk for inadvertent dural lacerations during flavectomy. Dissecting the ATA before the flavectomy may be an important step in reducing postoperative cerebrospinal fluid leaks, which may result in significant benefits for patients and health care organizations.
authors.affiliation: Department of Neurological Surgery, Ankara Atatürk Research and Education Hospital, Bilkent, Ankara, Turkey. isolaroglu@ku.edu.tr
authors.forename: Ihsan
authors.initials: I
authors.lastname: Solaroglu
authors.forename: Ozerk
authors.initials: O
authors.lastname: Okutan
authors.forename: Ethem
authors.initials: E
authors.lastname: Beskonakli
mesh_terms: D000328:Adult; D000368:Aged; D004388:Dura Mater / Q000473:pathology*; D005260:Female; D006801:Humans; D007796:Laminectomy / Q000379:methods; D008022:Ligaments / Q000473:pathology*; D017843:Ligamentum Flavum / Q000473:pathology* / Q000601:surgery; D008159:Lumbar Vertebrae / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic