Quality of Life, Psychosocial Burden, and Structural-functional Status in Adults With Spinal Deformity.

Inclusion Criteria: 1. Voluntary written informed consent of the participant or their legally authorized representative has been obtained prior to any screening procedures 2. Age at inclusion 18 years or older. 3. Diagnosed with Adult spinal deformity 4. Planned routine management through one of the following pathways: 1. Conservative/non-operative management; 2. Primary ASD surgery; 3. Revision ASD surgery. 5. Ability to complete the Dutch-language questionnaire package. Exclusion Criteria: 1. No valid informed consent. 2. Missing baseline structural imaging required for endpoint determination. We allow images to be older than 2 years if no new radiographs are obtained, in accordance with the ALARA principle. 3. Inability to complete the Dutch-language questionnaire package. 4. Known cognitive impairment, severe psychiatric condition, or other condition that, in the Investigator's judgement, precludes valid informed consent or reliable completion of study assessments. 5. Primary spinal condition other than adult spinal deformity that is expected to invalidate endpoint assessment, including acute traumatic, infectious, tumour-related, or inflammatory spinal pathology as the main reason for presentation.