Kyphosis

Fixed Sagittal Imbalance

Types of Sagittal Imbalance

Sagittal imbalance is either fixed or flexible. “Flexible” means the patient can stand up straight if they work at it (with their hips and knees straight), while “fixed” suggests they cannot. Similarly, the imbalance can be either compensated or decompensated. “Compensated” means the body can adapt (usually by flexing the knees and hips), while “decompensated” implies they cannot (see below). The problem leading to the imbalance is either local (a few vertebra causing significant tilt), regional (many vertebra causing a slow forward bend), or a mix of the two (see below).




Compensated vs. Decompensated Imbalance A) Compensated imbalance - A woman with traumatic lumbar kyphosis that compensates by extending her thoracic spine. Her weight-bearing (C7 plumb) line passes through S1. B) Decompensated fixed sagittal imbalance – the C7 plumb line is well anterior to S1.		Types of Fixed Sagittal Imbalance (FSI): FSI can be caused by a local problem involving a few vertebra, a global problem involving many vertebra, or a mix of the two.