Spinopelvic dissociation: extended definition, physical examination, classification, and therapy

Spinopelvic dissociation (SPD) is generally caused by high-energy injury mechanisms, and, in the absence of timely diagnosis and treatment, it can lead to chronic pain and progressive deformity. However, SPD is difficult to manage because of its rarity and complexity. In this study, we re-defined SPD according to the mechanism of injuries and biomechanical characteristics of the posterior pelvic ring and developed new classification criteria and treatment principles based on the classification for SPD.

Between June 2015 and September 2020, 30 patients with SPD which were selected from 138 patients with pelvic fractures were enrolled. Physical examination was performed, classification criteria (301 SPD classification) were developed, and specific treatment standards were established according to the classifications.

The injury mechanisms and co-existing injuries did not significantly differ between the classical SPD patients and expanded SPD patients. The 301 SPD classification criteria covered all the patients. Fixation by biplanar penetration screws was used in 7 patients, 11 patients received fixation by uniplanar penetration screws, 6 patients used sacroiliac compression screws, 3 patients received uniplanar screws combined with sacroiliac compression screws, and open spondylopelvic fixation was used in only 3 patients. According to the Matta criteria, 19, 7, and 4 patients achieved excellent, good, and fair reduction. The Majeed function score of the patients ranged from 9 to 96 points, and the mean score was 72.9 ± 24.6 points.

The expanded definition for SPD is particularly significant for definite diagnosis and prevention of missing diagnosis, based on which the 301SPD classification criteria can more systemically guide the clinical treatment of SPD, increase the treatment efficacy, and reduce surgical trauma. Chinese Clinical Trial Registry: ChiCTR-IPR-16009340.