Patient-reported outcome measures (PROMs) have become an important aspect of quality control in modern healthcare. In this prospective observational study on 199 patients undergoing thoracolumbar stabilization surgery, we quantified preoperative expectations and PROMs at six and twelve months after surgery, and we investigated what constitutes patient satisfaction with the outcome. We used the visual analogue scale (VAS) for pain and the Oswestry Disability Index (ODI). Preoperative expectations were high (expected ODI: 9 ± 13%; leg pain: 1.0 ± 1.4; back pain: 1.3 ± 1.5). Pain and disability improved substantially, but expectations were mostly unrealistic (ODI expectation fulfilled after six months: 28% of patients; back pain: 48%). However, satisfaction was high (70% at six months after surgery). Satisfied patients had significantly better pain and disability outcomes and higher rates of expectation fulfillment than non-satisfied patients. Patients undergoing revision stabilization had worse outcomes than all other diagnosis groups. Prior stabilization surgery was identified as an independent risk factor for dissatisfaction. There were no preoperative pain or disability levels that predicted dissatisfaction. The data presented in this study can provide benchmarks for diagnosis-specific PROM targets in thoracolumbar stabilization surgery. Future studies should investigate whether satisfaction can be influenced, e.g., by discussing realistic outcome targets with patients ahead of surgery.