Classification of Adult Spinal Deformity: Review of Current Concepts and Future Directions

Abstract

Although adult spinal deformity (ASD) has become a global health problem, the classification system and optimal surgical treatment for ASD is yet to be standardized worldwide. A significant part of the population, as high as 10%, in industrialized societies will be aged above 65 years within the next 10 years. Herein, a systematic review of the scientific literature related to the classification and treatment of ASD was conducted wherein historical to the most recent classifications of ASD were reviewed. By discussing the benefits and limitations of the previous classification systems and considering the factors affecting the clinical outcomes of surgical treatment of ASD, this article would like to propose future directions for the development of a new classification system for ASD.

Adult Spinal Deformity: Current Concepts and Decision-Making Strategies for Management

“…Classification systems for ASD demonstrate that clinical outcomes are vital for the accurate characterization of specific disorders that would facilitate evidence-based decision-making and management [16,17]. In 2005, Aebi [18] proposed a classification system based on etiology that is uniquely helpful in understanding the natural history of ASD.…”

“…In 2005, Aebi [18] proposed a classification system based on etiology that is uniquely helpful in understanding the natural history of ASD. However, Bess et al [16] proposed a new classification system that was based on "high-impact, clinically significant radiographic parameters" through a prospective study that investigated the clinical outcomes [17,19,20]. In 2012, the Scoliosis Research Society (SRS) Adult Deformity Committee revised the previously proposed system in order to include the pelvic parameters owing to substantial correlations with health-related quality of life (HRQoL) [17,19].…”

“…However, Bess et al [16] proposed a new classification system that was based on "high-impact, clinically significant radiographic parameters" through a prospective study that investigated the clinical outcomes [17,19,20]. In 2012, the Scoliosis Research Society (SRS) Adult Deformity Committee revised the previously proposed system in order to include the pelvic parameters owing to substantial correlations with health-related quality of life (HRQoL) [17,19]. Currently, the SRS-Schwab adult spine deformity classification is considered the standard system because all of its modifiers include spinopelvic parameters and owing to a strong correlation with the HRQoL scores [1,16].…”

“…These criteria apply to curves >30°. The modifiers include type T (thoracic only; thoracic major curve >30° at the apical level of T9 or higher), type L (TL/lumbar only; isolated thoracolumbar or lumbar curve >30° at the apical level of T10 or lower), type D (double major curve with thoracic and thoracolumbar/lumbar curve >30°), and type N (normal; no definite coronal deformity) [16][17][18][19].…”

“…If PT is <20°, the modifier is "0"; if the degree is 20°-30°, the modifier is "+"; if the degree is >30°, the modifier is "++. " Increases in PT correlate to pain and disability [16][17][18][19][20].…”