Faculty Bibliography

MINI: Despite differences in sagittal malalignment, antero-posterior pelvic translation maintained the position of T9 in line with the ankles, independently of sagittal vertical axis. Pelvic tilt was directly predicted by lower limb compensatory mechanisms. Therefore, these adaptation mechanisms being included in pelvic tilt analysis, it does not need additional consideration in the surgical planning. STUDY DESIGN: Retrospective review. OBJECTIVE: To investigate the role of lower limbs compensation with progressive sagittal malalignment. SUMMARY OF BACKGROUND DATA: Although lower limb compensatory mechanisms are established response to progressive sagittal malalignment, their specific role and potential impact on surgical planning has not been evaluated. METHODS: Single center retrospective review of full body x-rays was performed in patients of age >20 years. Parameters were measured with dedicated software. Population was stratified by 50 mm intervals of sagittal vertical axis (SVA) and one-way ANOVA was performed to compare P.shift (P.shift = anteroposterior translation of the pelvis vs. the feet) across SVA groups. Anteroposterior offset of each vertebra in relation to a vertical line extended from the distal tibial metaphysis (TM) was investigated. Linear regression was performed to predict pelvic tilt (PT) using Knee angle (KA) and P.shift, whereas controlling for pelvic incidence minus lumbar lordosis mismatch (PI-LL) and SVA. RESULTS: A total of 2124 patient visits were included (PI = 55.1 +/- 14.1 degrees , PT=21.0 +/- 11 degrees , PI-LL=6.3 +/- 17.3 degrees , SVA = 29 +/- 51 mm). With progressively increased SVA, P.shift decreased from 30 to -100 mm (all P < 0.005). Analysis of vertebral offset from the distal tibial metaphysis revealed that T9 was aligned with the TM line across all SVA groups. Prediction of PT based on PI-LL and SVA yielded R=0.76 (P < 0.001). Subsequent addition of KA and P.shift as independent parameters using hierarchical multiple regression led to significant improvement in R, demonstrating the independent role of lower limbs parameters in PT prediction. KA and P.shift had a positive standardized coefficient (all P < 0.05). CONCLUSION: Lower limb compensatory mechanisms increase with progressive sagittal malalignment. Anteroposterior translation of pelvis allows the T9 vertebra to remain in line with the ankle ("conus of economy"). Lower limb compensatory mechanisms are positive predictors of PT and thus do not require additional consideration in surgical realignment planning. LEVEL OF EVIDENCE: 3.

OBJECTIVE Although 3-column osteotomy (3CO) can provide powerful alignment correction in adult spinal deformity (ASD), these procedures are complex and associated with high complication rates. The authors' objective was to assess complications associated with ASD surgery that included 3CO based on a prospectively collected multicenter database. METHODS This study is a retrospective review of a prospectively collected multicenter consecutive case registry. ASD patients treated with 3CO and eligible for 2-year follow-up were identified from a prospectively collected multicenter ASD database. Early ( 6 weeks after surgery) complications were collected using standardized forms and on-site coordinators. RESULTS Of 106 ASD patients treated with 3CO, 82 (77%; 68 treated with pedicle subtraction osteotomy [PSO] and 14 treated with vertebral column resection [VCR]) had 2-year follow-up (76% women, mean age 60.7 years, previous spine fusion in 80%). The mean number of posterior fusion levels was 12.9, and 17% also had an anterior fusion. A total of 76 early (44 minor, 32 major) and 66 delayed (13 minor, 53 major) complications were reported, with 41 patients (50.0%) and 45 patients (54.9%) affected, respectively. Overall, 64 patients (78.0%) had at least 1 complication, and 50 (61.0%) had at least 1 major complication. The most common complications were rod breakage (31.7%), dural tear (20.7%), radiculopathy (9.8%), motor deficit (9.8%), proximal junctional kyphosis (PJK, 9.8%), pleural effusion (8.5%), and deep wound infection (7.3%). Compared with patients who did not experience early or delayed complications, those who had these complications did not differ significantly with regard to age, sex, body mass index, Charlson Comorbidity Index, American Society of Anesthesiologists score, smoking status, history of previous spine surgery or spine fusion, or whether the 3CO performed was a PSO or VCR (p >/= 0.06). Twenty-seven (33%) patients had 1-11 reoperations (total of 44 reoperations). The most common indications for reoperation were rod breakage (n = 14), deep wound infection (n = 15), and PJK (n = 6). The 24 patients who did not achieve 2-year follow-up had a mean of 0.85 years of follow-up, and the types of early and delayed complications encountered in these 24 patients were comparable to those encountered in the patients that achieved 2-year follow-up. CONCLUSIONS Among 82 ASD patients treated with 3CO, 64 (78.0%) had at least 1 early or delayed complication (57 minor, 85 major). The most common complications were instrumentation failure, dural tear, new neurological deficit, PJK, pleural effusion, and deep wound infection. None of the assessed demographic or surgical parameters were significantly associated with the occurrence of complications. These data may prove useful for surgical planning, patient counseling, and efforts to improve the safety and cost-effectiveness of these procedures.

Introduction: Recent research in sagittal plane proposed ageadjusted alignment thresholds. However, impact of these thresholds on postoperative HRQL is yet to be investigated. This study aims to compare 2 yr clinical outcomes of patients (pts) who underwent surgical reconstructions based on their achievement to age-adjusted alignment ideals. Material and Methods: Retrospective review of prospectively collected database. Patients were included if > 18 years, underwent surgical correction of adult spinal deformity with a complete 2 yr FU. Pts were stratified into 3 groups based on achievement of age-adjusted thresholds in pelvic tilt (PT), pelvic incidence minus lumbar lordosis (PI-LL), sagittal vertical axis (SVA). First group included pts who reached the exact age-adjusted threshold +/-10 yrs (MATCHED), other two groups included pts who were over corrected (OVER), and under corrected (UNDER). Clinical outcomes including actual value and offset from age-adjusted ODI, SF36-PCS and SRS-22 (PROM) were compared between groups at 2 yr FU. Results: 343 patients (57.0 years and 83% F) were included. Sagittal profile of the population was: PT = 23.6degree, SVA = 65.8mm, PI-LL = 15.6degree. At 2-year follow-up there was a significant improvement in all sagittal modifiers with 25.7%, 24.3% and 33.1% of the patients matching their age alignment targets in terms of PT, PI-LL and SVA respectively. For PT and PI-LL the 3 groups (MATCHED, OVER, UNDER) had comparable values and offsets from age-adjusted PROM. However, for SVA groups, patients in UNDER had significantly worse HRQOL than the two other groups. Patients in PT, PI-LL, and SVA UNDER groups were significantly younger than the other groups, P < .05. Conclusion: At 2 yr following ASD surgical treatment only 24.3% to 33.1% of the pts reached age-adjusted alignment thresholds. Those under corrected in SVA demonstrated worse clinical outcomes. No significant improvements were found between matched and overcorrected pts, with overcorrection being an established risk for PJK. These results further emphasize the need for patient specific operative planning

STUDY DESIGN: Retrospective review of a prospective database. OBJECTIVE: To define the role of sagittal orientation of the construct at the upper instrumented levels in the development of proximal junctional kyphosis (PJK) in adult spinal deformity (ASD) patients. SUMMARY OF BACKGROUND DATA: PJK following ASD surgery remains challenging. The final alignment of the upper instrumented vertebral segments has been proposed as a risk factor for PJK, but has not been fully investigated. METHODS: ASD patients with 2-yr follow-up and long posterior fusion to the pelvis were analyzed. Radiographic measurements included pelvic incidence (PI), lumbar lordosis (LL), pelvic tilt (PT), SVA, and 2 UIV parameters: UIV slope (UIV vs horizontal) and inclination of the proximal-end of the construct. UIV parameters were secondarily evaluated with regard to the compensatory impact of post-PJK increased PT (PREF). A comparison between PJK and non-PJK patients was performed, according to the UIV location (UT = upper thoracic or TL = thoracolumbar). RESULTS: 252 patients (mean age 61.5 yo, 83% F) were included. PJK incidence was 56% at 2-yrs. PJK patients had a greater change in lumbar lordosis and thoracic kyphosis than non-PJK patients. In the UT group, there was no difference in UIV slope for PJK vs non-PJK. However PJK patients had a smaller inclination of the upper instrumented segments vs vertical (p < 0.001) and the PREF (p = 0.005). Similarly, in the LT group, PJK patients had a posterior inclination vs. the vertical (p < 0.001) and the PREF (p = 0.041). CONCLUSION: Analysis revealed that a more posterior construct inclination was present in patients who developed PJK. These results support previous hypotheses suggesting that PJK may develop in response to excessive spinal realignment. Proper rod contouring, especially at the proximal end may reduce the risk of PJK. LEVEL OF EVIDENCE: 3.

STUDY DESIGN: Retrospective study OBJECTIVE:: To propose radiographic characteristics of patients with cervical disability and to investigate the relevant parameters when assessing cervical alignment. SUMMARY OF BACKGROUND DATA: Although cervical kyphosis is traditionally recognized as presentation of cervical deformity, an increasing number of studies demonstrated that cervical kyphosis may not equal cervical deformity. Therefore, several other differentiating criteria for cervical deformity should be investigated and supported with quality of life scores. METHODS: A database of full-body radiographs was retrospectively reviewed. Patients without previous cervical surgery, with a well aligned thoracolumbar profile (defined as T1 pelvis angle (TPA) <15 degrees ) and with an available Neck Disability Index (NDI) score were reviewed in this study. Subjects were stratified into an asymptomatic (64 subjects with NDI15, VAS neck>3, or VAS arm>3). Independent t-tests were performed to investigate differences between two groups. Logistic regressions and principle component analyses were then performed. RESULTS: NDI averaged 5.43 in asymptomatic group, significantly smaller than symptomatic group (5.43 vs. 41.25). T-test revealed that C2-C7 SVA, McGregor slope (McGS) and the slope of line of sight (SLS were significantly different while C2C7 angle (Cervical curvature, CC) did not show statistical difference (P = 0.09). Logistic regressions were performed using the significantly different parameters as well as CC. Results identified C2-C7 SVA and SLS as independent risk factors for low HRQoL. The principle component analysis, lead to a new factor (0.55 x C2C7 SVA + 0.34 x C0C2 + 0.77 x CC) with strong correlations with NDI, VAS and EQ5D measurements. CONCLUSION: The traditional concept of cervical kyphosis should not be regarded as a standalone criterion of cervical deformity. The most clinically relevant components of cervical analysis are the C2-C7 SVA, C0C2 angle and C2C7 angle. In addition, the three components should be assessed in together in harmony and not individually. LEVEL OF EVIDENCE: 4.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: Assess outcomes of adult spinal deformity (ASD) surgery performed by 1 vs. 2 attending surgeons. SUMMARY OF BACKGROUND DATA: ASD centers have developed 2-attending teams in order to improve efficiency; their effects on complications and outcomes have not been reported. METHODS: ASD patients with >/=5 levels fused and > 2-year follow-up were included. Estimated blood loss (EBL), length of stay (LOS), operating room (OR) time, complications, quality of life (HRQOL) and X-rays were analyzed. Outcomes were compared between 1-surgeon (1S) and 2-surgeon (2S) centers. A deformity-matched cohort was analyzed. RESULTS: 188 patients in 1S and 77 in 2S group were included. 2S group patients were older and had worse deformity based on the SRS-Schwab classification (p < 0.05). There were no significant differences in levels fused (p = 0.57), LOS (8.7 vs. 8.9 days), OR time (445.9 vs. 453.2 min) or EBL (2008 vs. 1898 cc; p > 0.05). 2S patients had more 3-column osteotomies (3CO; p < 0.001) and used less bone morphogenetic protein 2 (BMP-2; 79.9 vs. 15.6%; p < 0.001). The 2S group had fewer intra-operative complications (1.3 vs. 11.1%; p = 0.006). Post-operative (6-weeks to 2-year) complications were more frequent in the 2S group (4.8 vs. 15.6%; p < 0.002). After matching for deformity, there were no differences in LOS (9.1 vs. 10.1 days), OR time (467.8 vs. 508.4 min) or EBL (3045 vs. 2247 cc; p = 0.217). 2S group used less BMP-2 (20.6 vs. 84.8%; p < 0.001), had fewer intra-operative complications (p = 0.015) but post-operative complications due to instrumentation failure/pseudarthrosis were more frequent (p < 0.01). CONCLUSIONS: No significant differences were found in LOS, OR time or EBL between the 1S and 2S groups, even when matching for severity of deformity. 2S group had less BMP-2 use, fewer intra-operative complications but more post-operative complications. LEVEL OF EVIDENCE: 2.

STUDY DESIGN: Single-center retrospective review. OBJECTIVE: This study evaluates the impact of increasing spinal deformity deviation from age-adjusted alignment ideals on lower extremity compensation. SUMMARY OF BACKGROUND DATA: Though current understanding of compensatory mechanisms in adult spinal deformity (ASD) is progressing due to full-body stereographic assessment, the impact of age-adjusted deformity targets on lower limb compensation remains unexamined. METHODS: ASD patients >/=18 years with biplanar full-body stereographic x-rays were included. Patients were stratified into age cohorts: <40y, 40-65y, >/=65y. Age-specific alignment goals (IDEAL) for pelvic tilt (PT), spino-pelvic mismatch (PI-LL), sagittal vertical axis (SVA), and T1 pelvic angle (TPA) were calculated for each patient using published formulas and compared to patients' real (ACTUAL) radiographic parameters. The difference between ACTUAL and IDEAL alignment (OFFSET) was calculated. ANOVA compared ACTUAL, IDEAL, and OFFSET between age groups, and OFFSET was correlated with lower-limb compensation (SFA: sacrofemoral angle, PS: pelvic shift, KA: knee angle, AA: ankle angle). RESULTS: 778 ASD patients (74.1% female) were included. ACTUAL and IDEAL alignments matched for PT (p = 0.37) in patients <40yrs, SVA (p = 0.12) in patients 40-65 yrs and PT, SVA and TPA (p > 0.05) in patients >/=65yrs. SVA and TPA OFFSETs decreased significantly with increasing age (p<0.001). Hip extension correlated with all OFFSETs in patients <40yrs (positively with PT, PI-LL, TPA; negatively with SVA). Knee flexion correlated with PI-LL, SVA, TPA, across all age groups with strongest correlations (0.52540yr) age groups. Posterior pelvic displacement correlated positively with all OFFSET groups, and was highest (0.526

PMID: 27974739

ISSN: 1528-1159

CID: 2363562