Thoracic and Abdominal Complications After Posterior Fusion for Adolescent Idiopathic Scoliosis: Evidence and Clinical Implications

Background: Posterior spinal fusion (PSF) is an established treatment for progressive adolescent idiopathic scoliosis (AIS) requiring surgery. Thoracic and abdominal complications range from transient postoperative findings to uncommon emergencies. This narrative review examines their reported frequency, recognition, prevention, and management. Methods: Literature published between January 2000 and June 2026 was reviewed using PubMed/MEDLINE and Google Scholar, supplemented by reference-list screening. AIS-specific evidence was prioritized. Reports involving other deformities or surgical approaches and general management guidelines were used as explicitly identified contextual evidence. No pooled incidence estimates were calculated. Results: Reported frequencies depended strongly on outcome definitions, imaging protocols, surgical approach, and follow-up. Two retrospective AIS studies detected pleural effusion in 71.0% and 76.3% of patients on computed tomography approximately one week after PSF; in the latter study, all effusions were asymptomatic and required no treatment. These findings should not be equated with clinically significant pulmonary complications. Postoperative ileus was reported in 13.2% of one 318-patient AIS cohort aged 10–20 years, whereas superior mesenteric artery syndrome, chylothorax, hemothorax, and implant-related vascular injury were supported largely by small series or case reports. Enhanced recovery pathways were consistently associated with shorter hospitalization, but evidence that they prevent individual rare complications was limited. Accurate instrumentation, appropriate blood conservation, individualized nutritional assessment, opioid-sparing analgesia, and symptom-directed investigation support perioperative care. Conclusions: Thoracic and abdominal complications after PSF for AIS require separate interpretation of radiographic findings, clinically diagnosed events, and events requiring intervention. Persistent vomiting, progressive abdominal distension, respiratory deterioration, unexplained anemia, or hemodynamic instability warrant prompt reassessment. Management should follow the suspected diagnosis, patient physiology, and relevant pediatric or multidisciplinary guidance.