Bradley Harris

Global sagittal axis: a step toward full-body assessment of sagittal plane deformity in the human body.

OBJECTIVE Sagittal malalignment requires higher energy expenditure to maintain an erect posture. Because the clinical impact of sagittal alignment is affected by both the severity of the deformity and recruitment of compensatory mechanisms, it is important to investigate new parameters that reflect both disability level and compensatory mechanisms for all patients. This study investigated the clinical relevance of the global sagittal axis (GSA), a novel measure to evaluate the standing axis of the human body. METHODS This is a retrospective review of patients who underwent full-body radiographs and completed health-related quality of life (HRQOL) questionnaires: Oswestry Disability Index (ODI), Scoliosis Research Society-22, EuroQol-5D (EQ-5D), and the visual analog scale for back and leg pain. The GSA was defined as the angle formed by a line from the midpoint of the femoral condyles to the center of C-7, and a line from the midpoint between the femoral condyles to the posterior superior corner of the S-1 sacral endplate. After evaluating the correlation of GSA/HRQOL with sagittal parameters, linear regression models were generated to investigate how ODI and GSA related to radiographic parameters (T-1 pelvic angle, pelvic retroversion, knee flexion, and pelvic posterior translation). RESULTS One hundred forty-three patients (mean age 44 years) were included. The GSA correlated significantly with all HRQOL (up to r = 0.6 with EQ-5D) and radiographic parameters (up to r = 0.962 with sagittal vertical axis). Regression between ODI and sagittal radiographic parameters identified the GSA as an independent predictor (r = 0.517, r2 = 0.267; p < 0.001). Analysis of standardized coefficients revealed that when controlling for deformity, the GSA increased with a concurrent decrease in pelvic retroversion (-0.837) and increases in knee flexion (+0.287) and pelvic posterior translation (+0.193). CONCLUSIONS The GSA is a simple, novel measure to assess the standing axis of the human body in the sagittal plane. The GSA correlated highly with spinopelvic and lower-extremities sagittal parameters and exhibited remarkable correlations with HRQOL, which exceeded other commonly used parameters.

Developing the Total Disability Index Based on an Analysis of the Interrelationships and Limitations of Oswestry and Neck Disability Index.

Study Design. Retrospective. Objective. This study assessed the feasibility of combining Oswestry and Neck Disability Index (ODI and NDI) into 1 shorter “Total Disability Index” (TDI) from which reconstructed scores could be computed. Summary of Background Data. ODI and NDI are not pure assessments of disability related to back and neck, respectively. Because of similarities/redundancies of questions, ODI scores may be elevated in neck-pain patients and the converse is true for NDI in back-pain patients. Methods. Spine patients completed ODI and NDI, and complaints were recorded as back pain (BP), neck pain (NP), or both (BNP). Questionnaire scores were compared across cohorts via descriptives and Spearman (&rgr;) correlations. In exploring the feasibility of merging ODI/NDI, TDI was constructed from 9 ODI and 5 NDI items. Extracting questions from TDI, reconstructed 9-item rODI and 10-item rNDI indices were formed and compared with true ODI/NDI. Results. There were a total of 1207 patients: 741 BP, 134 NP, and 268 BNP. Mean ODI was 37 ± 21 and mean NDI was 32 ± 21. Patients with concurrent BP and NP had significantly more disability. Seventy-eight patients of 134 (58%) patients with NP only had at least “moderate disability” by ODI and 297 of 741 (40%) patients with back pain only, had at least “moderate disability” by NDI. ODI versus NDI correlation was &rgr; = 0.755; ODI versus reconstructed rODI correlated at &rgr; = 0.985, and NDI versus reconstructed rNDI correlated at &rgr; = 0.967 (P < 0.01). Conclusion. Elevated ODI/NDI scores in patients with isolated complaints show that disability in 1 region affects scores on both surveys. This study constructed a 14-item TDI that represents every domain of ODI/NDI with exception of ODI “Sex Life.” From this TDI, reconstructed scores correlated near perfectly with true scores. TDI provides a more global assessment of spinal disability and is a questionnaire that reduces the time burden to patients. The TDI allows for simultaneous assessment of back, neck, and global spinal disability. Level of Evidence: 2

Investigating the Universality of Preoperative Health-Related Quality of Life (HRQoL) for Surgically Treated Spinal Deformity in Young Adults: A Propensity Score–Matched Comparison Between African and US Populations

STUDY DESIGN Retrospective analysis of propensity score-matched (PSM) observational cohorts. OBJECTIVES To evaluate and compare preoperative health-related quality of life (HRQoL) scores and radiographic measurements of young African and US adults with spinal deformity (ASD). SUMMARY OF BACKGROUND DATA Young ASD patients in the United States are motivated more to correct coronal and sagittal plane deformities than to alleviate pain. Motivations for surgical correction in young ASD patients in Africa have not been previously investigated. METHODS Retrospective review of two large databases of African and US patients with ASD. African patients who underwent ASD surgery were PSM by age, gender, and pelvic tilt with US patients. Preoperative radiographic parameters and HRQoL scores (ODI, SRS-22r, back/leg pain) were compared between cohorts. Pearson correlations used to evaluate relationships between radiographic parameters and HRQoL scores. RESULTS Fifty-four US patients (average age 22.9 ± 4.9 years; 0% African American) and 54 African patients (24.6 ± 7.2 years) met inclusion criteria. Compared to the United States, African patients had significantly lower body mass index (21.1 ± 3.3 vs. 24.6 ± 7.2) and more severe scoliosis, coronal malalignment, and sagittal malalignment (p < .05). Africans also had significantly better Oswestry Disability Index (12.8 vs. 17.7), worse Scoliosis Research Society questionnaire (SRS-22r)-Appearance (2.5 vs. 3.2), SRS-Function (3.3 vs. 3.9), and SRS-Total (3.2 vs. 3.5) scores than US patients (p < .05). SRS-Appearance scores correlated with Cobb angles of the upper thoracic (r = -0.321), thoracic (r = -0.277), and thoracolumbar (r = -0.300) curves for US patients. For African patients, global sagittal alignment and C7 inclination correlated with SRS-Appearance (r = -0.347, -0.346, respectively). CONCLUSIONS Young African ASD patients have significantly more severe deformity, less disability, and worse SRS-22r scores preoperatively than a matched cohort of US patients. Spinal deformity and associated poor self-image appear to be the major drivers of surgical intervention in this cohort. Global malalignment in African patients is most closely correlated with appearance scores and should be surgically addressed accordingly. LEVEL OF EVIDENCE Level III.