The primary rationale for flexion-distraction is to open the posterior annulus and reduce intradiscal pressure by what mechanism?

The primary rationale for flexion-distraction is to open the posterior annulus and reduce intradiscal pressure by what mechanism?

• A. Increasing anterior shear
• B. Providing rotational correction
• C. Gapping of the posterior annulus
• D. Accelerating disc degeneration

Answer: (C)

Flexion-distraction decompresses the disc by distracting the motion segment in a flexed position, which mainly opens the posterior portion of the disc. This creates a gap in the posterior annulus, lowering intradiscal pressure and allowing the nucleus to spread out and the posterior structures to decompress. The resulting relief on the posterior annulus and nerve roots is the core therapeutic effect. Other options describe changes that aren’t how this technique works: increasing anterior shear doesn’t produce the posterior opening; rotational correction isn’t the primary mechanism; accelerating disc degeneration would be counterproductive to decompression.

Flexion-distraction decompresses the disc by distracting the motion segment in a flexed position, which mainly opens the posterior portion of the disc. This creates a gap in the posterior annulus, lowering intradiscal pressure and allowing the nucleus to spread out and the posterior structures to decompress. The resulting relief on the posterior annulus and nerve roots is the core therapeutic effect. Other options describe changes that aren’t how this technique works: increasing anterior shear doesn’t produce the posterior opening; rotational correction isn’t the primary mechanism; accelerating disc degeneration would be counterproductive to decompression.