A Novel Classification of Sagittal Spinal Alignment to Aid Surgical Planning for Adult Spinal Deformity

Condition(s) studied

Investigational drug(s) / intervention(s)

Correction strategy in reference to our PI-dependent clustering of sagittal alignment: For type I patients (PI \< 39.56°), the target LL = -0.13\*PI2+9.36\*PI-134.08; for type II patients (39.56° ≤ PI \< 49.16°), the target LL = 0.45\*PI+26.57; for type III patients (49.16° ≤ PI \< 58.31°), the target LL = -0.15\*PI2+17.09\*PI-420.57; for type IV patients (PI \> 58.31°), the target LL = 0.06\*PI2-7.55\*PI+289.77. Prediction intervals of 95% confidence is adopted as the target LL range.

Correction strategy in reference to the SAAS score: This new score is composed of three sagittal parameters (PI-LL, PT and TPA). For these three parameters, points were assigned based on offset with age-adjusted targets 0 points if the parameter was within 10 years of the patient's age (Match). For each 20 years above the age-adjusted target, 1 point was added (e.g., + 1 point between + 10 and + 30, + 2 points between +30 and +50). Conversely, 1 point was subtracted for each 20 years below the age-adjusted target (e.g., -1 point between -10 and -30, -2 points between -30 and -50). SAAS was calculated by adding all 3 components, creating a discreet score that could have a negative value (under corrected) or positive value (over corrected). SAAS was sub-categorized into "SAAS-Under" if it was less than -1, "SAAS-Match" if it was between -1 and + 1 or "SAAS-Over" if it was greater than + 1.

Study summary

Surgical outcomes, including radiographic outcomes, patient-reported outcomes, postoperative complications, and revision surgery rates, were compared in patients with adult spinal deformity who underwent correction surgery with reference to our pelvic incidence-dependent (PI-dependent) clustering of sagittal spinal alignment and existing standards (sagittal age-adjusted score \[SAAS\], global alignment and proportion \[GAP\] score, and Roussouly classification). Our findings may provide tangible guidance for surgical decision-making in ASD.

Eligibility

Primary outcome measure(s)

• Proximal Junctional Kyphosis — Two years after surgery
  Proximal junctional kyphosis (PJK) was defined by a proximal junctional angle (PJA) (Cobb angle between the superior endplate of UIV+2 and inferior endplate of UIV) of \> 10° and a PJA angle difference of \> 10° from baseline at any time point up to latest follow-up.

Trial sites (1)

More Xuanwu Hospital, Beijing trials in China

Other trials for the same condition