Advances in the application of spinal anesthesia in patients with spinal structural abnormalities

Spinal anesthesia is a fundamental and widely adopted technique in modern clinical practice. However, its application in patients with abnormal spinal anatomy remains contentious due to heightened risks of technical failure, neurological injury, and hemodynamic instability. This review synthesizes recent advances in the use of spinal anesthesia in this complex patient population, providing clinical insights and practical recommendations derived from a comprehensive analysis of over 40 studies retrieved from the PubMed and Web of Science databases. Findings suggest that subarachnoid block may offer higher success rates than epidural block in patients with a history of spinal surgery. Among individuals with scoliosis, the failure rate of neuraxial block was markedly higher in those with a Cobb angle greater than 50° (26.9%) compared to those with milder deformities (7.5%). Furthermore, symmetrical bilateral spread of local anesthetics was more frequently observed in patients with left-sided scoliosis (52.9%) than in those with right-sided curvature (28.1%). To optimize puncture success, a needle insertion angle of 4.1±2.45° from the midline is recommended for patients with Cobb angles less than 50°, and 9.14±2.45° for those with Cobb angles exceeding 50°. In cases of ankylosing spondylitis, the paramedian approach, in combination with electromagnetic needle tracking systems such as SonixGPS^®, has shown improved procedural efficacy. Despite these promising developments, large-scale, multicenter clinical trials are urgently required to establish standardized protocols, refine anesthetic dosing strategies, and reduce the incidence of neurological complications in patients with altered spinal anatomy.