Patients aged 40-75 years affected by lumbar or thoraco-lumbar degenerative kyphoscoliosis presenting chronic low back pain from six months at least and/or neurological deficits who underwent a surgical correction of the deformity

Three different surgical techniques are used:

• lumbar fusion vs thoraco-lumbar fusion
• iliac fixation vs fixation to the sacrum
• posterior + interbody fusion vs posterior interbody fusion

The clinical status of the patients will be evaluated before surgery and at 1-3-6-12 months of follow up (and then annually) by: 1. Visual Analog Scale (VAS); 2. Oswestry Disability Index (ODI); 3. Quality of life (EuroQoL 5D) test.

The correction of the deformity with respect to the pre-operative status will be assessed by anteroposterior, bending and lateral full standing radiographs at 1-3-6-12 months of follow up (and then annually). Flexion/extension radiographs will be taken at 1-3-6-12 months after surgery in order to evaluate fusion and proper positioning of hardware. Successful arthrodesis (fusion) will be also confirmed by CT scan at 1 year.

Criteria of fusion evaluation:

1. Fusion certain
2. Fusion likely
3. Status uncertain
4. Pseudo arthrosis likely
5. Pseudo arthrosis certain

The psychological state of the patients will be evaluate before the surgical treatment and at 1-3-6-12 months after surgery (then annually).

To evaluate the psychological state of the patients the following questionnaires will be used:

• STAI to evaluate the anxiety state
• ZHUNG to evaluate the depressive state

Major and minor surgical complications will be recorded and analysed during the perioperative period (early complications) and at 1-3-6-12 months after surgery (late complications).