title: Retaining intradiscal pressure after annulotomy by different annular suture techniques, and their biomechanical evaluations.
abstract: BACKGROUND
  The adverse effects of annulotomy during lumbar discectomy have been increasingly recognized, and methods are developing to repair the annular defect. Biomechanically, the repair should retain the intra-nuclear pressure, which is doubtful using the current suture techniques. Therefore, a new suture technique was designed and tested to close a simpler type of annular incision.
  
  
  METHODS
  A new suture technique, the modified purse-string suture, was introduced into a re-validated nonlinear finite element human disk model after creating a standard transverse slit incision, as well as two other suture techniques: either two simple sutures, or a horizontal crossed suture, and compared their contact pressure on the cleft contact surface. Then, porcine lumbar endplate-disk-endplate complexes with transverse slit incisions were repaired using the three techniques. Quantitative discomanometry was then applied to compare their leakage pressure, as a parameter of disk integrity.
  
  
  RESULTS
  In finite element model, the new technique created the greatest contact pressure along the suture range (the outer annulus), and generated a minimum contact pressure at the critical point, which was 68% and 55% higher than the other two suture techniques. In quantitative discomanometry, the new suture technique also had an average leakage pressure of 85% and 49% higher than the other two suture techniques.
  
  
  CONCLUSIONS
  The modified purse-string suture can generate higher contact pressure than the other two techniques at finite element analysis and in realistic animal models, which aids in retaining intra-discal pressure, and should be encouraged in clinical practice.
authors: Department of Orthopaedic Surgery, Buddhist Tzu Chi General Hospital, Taichung Branch, No. 66 Sec. 1 Fongsing Road, Tanzih Township. Taichung County, Taiwan.
authors: Yueh-Feng
authors: YF
authors: Chiang
authors: Chang-Jung
authors: CJ
authors: Chiang
authors: Chih-Hong
authors: CH
authors: Yang
authors: Zheng-Cheng
authors: ZC
authors: Zhong
authors: Chen-Sheng
authors: CS
authors: Chen
authors: Cheng-Kung
authors: CK
authors: Cheng
authors: Yang-Hwei
authors: YH
authors: Tsuang
mesh_terms: D002102:Cadaver; D019245:Compressive Strength; D003198:Computer Simulation; D017586:Diskectomy / Q000379:methods*; D055119:Elastic Modulus; D006801:Humans; D007403:Intervertebral Disc / Q000503:physiopathology* / Q000601:surgery*; D008954:Models, Biological; D011312:Pressure; D013314:Stress, Mechanical; D013536:Suture Techniques