This thesis aimed to evaluate the effectiveness of surgical treatment options to correct spinal malalignment and explore various concepts of pelvic osteotomies as a potential alternative to spinal correction osteotomies. The relationship between surgical correction of sagittal spinal alignment and patient-reported outcomes was evaluated through a systematic review and meta-analysis in Chapter 2. The study analyzed 34 observational studies involving 973 patients. Among the spinopelvic parameters examined, PT emerged as a key indicator, with significant correlations identified between reduced PT and improvements in the ODI and VAS scores. These findings highlight the importance of addressing PT during surgical planning to achieve optimal outcomes. However, the review revealed limitations in the available evidence, including methodological heterogeneity and a lack of randomized controlled trials. In Chapter 3, a survey conducted among Dutch spine surgeons revealed a broad awareness of the importance of sagittal balance in managing spinal disorders. While orthopedic surgeons demonstrated a higher adoption rate of spinopelvic parameters in decision-making, neurosurgeons applied these principles less consistently. These parameters were recognized as crucial for surgical planning, yet their application in routine practice varied. This disparity between theoretical knowledge and clinical implementation indicates a need for standardized diagnostic protocols and surgeon training. Chapter 4 describes an experimental study on cadaveric models to compare different surgical approaches for restoring lumbar lordosis. The different steps of posterior element resections as part of posterior interbody fusion each contributed statistically significantly to the restoration of segmental lordosis, with bilateral facetectomy contributing the most in percentage. Chapter 5 investigated the feasibility of reducing PI through a novel bilateral anterior open-wedge osteotomy of the ilium, termed BEPO. The BEPO effectively reduced PI, offering a promising alternative for correcting sagittal imbalance, particularly in cases where lumbar osteotomies are insufficient. The anatomical feasibility of the technique was supported, although correction was limited and clinical validation is necessary. In Chapter 6, various pelvic osteotomies were compared in an in-silico model. A-DPO appeared to be the most predictable and reliable DPO. However, it is technically demanding and shortens the pelvic floor ligaments. BEPO is less demanding and has minimal effect on the ligaments but requires more complex stabilization methods.