Retaining intradiscal pressure after annulotomy by different annular suture techniques, and their biomechanical evaluations

Chiang, Yueh-Feng; Chiang, Chang-Jung; Yang, Chih-Hong; Zhong, Zheng-Cheng; Chen, Chen-Sheng; Cheng, Cheng-Kung; Tsuang, Yang-Hwei

doi:10.1016/j.clinbiomech.2011.09.008

« Previous Next »Clinical Biomechanics
Volume 27, Issue 3 , Pages 241-248, March 2012

Retaining intradiscal pressure after annulotomy by different annular suture techniques, and their biomechanical evaluations

Yueh-Feng Chiang
- Department of Orthopaedic Surgery, Buddhist Tzu Chi General Hospital, Taichung Branch, No. 66, Sec. 1, Fongsing Road, Tanzih Township. Taichung County, Taiwan
- Orthopaedic Biomechanics Laboratory, Institute of Biomedical Engineering, National Yang Ming University, No.155, Sec.2, Linong Street, Taipei City, Taiwan
Chang-Jung Chiang
- Department of Orthopedics, Shuang Ho Hospital, Taipei Medical University, No. 291,Jhongjheng Road, Zhonghe District, New Taipei City, Taiwan
Chih-Hong Yang
- Orthopaedic Biomechanics Laboratory, Institute of Biomedical Engineering, National Yang Ming University, No.155, Sec.2, Linong Street, Taipei City, Taiwan
- Department of Orthopaedic surgery, Kuang Tien General Hospital, No.117, Shatian Road., Shalu Township, Taichung County, Taiwan
Zheng-Cheng Zhong
- Institute of Physical Therapy and Assistive Technology, National Yang Ming University, No.155, Sec.2, Linong Street, Taipei City, Taiwan
Chen-Sheng Chen
- Institute of Physical Therapy and Assistive Technology, National Yang Ming University, No.155, Sec.2, Linong Street, Taipei City, Taiwan
Cheng-Kung Cheng
- Orthopaedic Biomechanics Laboratory, Institute of Biomedical Engineering, National Yang Ming University, No.155, Sec.2, Linong Street, Taipei City, Taiwan
- Corresponding author.
Yang-Hwei Tsuang
- Department of Orthopedics, Shuang Ho Hospital, Taipei Medical University, No. 291,Jhongjheng Road, Zhonghe District, New Taipei City, Taiwan
- Corresponding author.

Received 7 May 2011; accepted 20 September 2011. published online 17 October 2011.

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.

Findings

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.

Interpretation

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.

Keywords: annulotomy, intradiscal pressure, annular repair, modified purse-string suture (MPSS), finite element analysis, quantitative discomanometry