When patient is not able to see in front, we need to do deformity correction by doing osteotomy at the level of lumbar spine as shown in picture.
2.The stability of the spine is compromised. An unstable spine means that it moves too much and the joints aren't controlling the spine mobility as they should. Spinal instability puts the patients more at risk for nerve damage.
3.Neurologic deficit exists. "Neurologic deficit" means a nerve problem that causes sensory (eg, pain, tingling sensations) and/or motor changes (eg, weakness).
4.Fracture - Fractures in ankylosing spondylitis are common due to stiff spine and osteoporosis. Fractures in ankylosing spondylitis are highly unstable and mostly associated with neurological deficit.