Persistent Lower Extremity Compensation for Sagittal Imbalance After Surgical Correction of Complex Adult Spinal Deformity: A Radiographic Analysis of Early Impact.


Achieving spinopelvic realignment during adult spinal deformity (ASD) surgery does not always produce ideal outcomes. Little is known whether compensation in lower extremities (LEs) plays a role in this disassociation. The objective is to analyze lower extremity compensation after complex ASD surgery, its effect on outcomes, and whether correction can alleviate these mechanisms. We included patients with complex ASD with 6-week data. LE parameters were as follows: sacrofemoral angle, knee flexion angle, and ankle flexion angle. Each parameter was ranked, and upper tertile was deemed compensation. Patients compensating and not compensating postoperatively were propensity score matched for body mass index, frailty, and T1 pelvic angle. Linear regression assessed correlation between LE parameters and baseline deformity, demographics, and surgical details. Multivariate analysis controlling for baseline deformity and history of total knee/hip arthroplasty evaluated outcomes. Two hundred and ten patients (age: 61.3 ± 14.1 years, body mass index: 27.4 ± 5.8 kg/m2, Charlson Comorbidity Index: 1.1 ± 1.6, 72% female, 22% previous total joint arthroplasty, 24% osteoporosis, levels fused: 13.1 ± 3.8) were included. At baseline, 59% were compensating in LE: 32% at hips, 39% knees, and 36% ankles. After correction, 61% were compensating at least one joint. Patients undercorrected postoperatively were less likely to relieve LE compensation (odds ratio: 0.2, P = .037). Patients compensating in LE were more often undercorrected in age-adjusted pelvic tilt, pelvic incidence, lumbar lordosis, and T1 pelvic angle and disproportioned in Global Alignment and Proportion (P < .05). Patients matched in sagittal age-adjusted score at 6 weeks but compensating in LE were more likely to develop proximal junctional kyphosis (odds ratio: 4.1, P = .009) and proximal junctional failure (8% vs 0%, P = .035) than those sagittal age-adjusted score-matched and not compensating in LE. Perioperative lower extremity compensation was a product of undercorrecting complex ASD. Even in age-adjusted realignment, compensation was associated with global undercorrection and junctional failure. Consideration of lower extremities during planning is vital to avoid adverse outcomes in perioperative course after complex ASD surgery.





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Publication Info

Williamson, Tyler K, Tyler K Williamson, Pooja Dave, Jamshaid M Mir, Justin S Smith, Renaud Lafage, Breton Line, Bassel G Diebo, et al. (2024). Persistent Lower Extremity Compensation for Sagittal Imbalance After Surgical Correction of Complex Adult Spinal Deformity: A Radiographic Analysis of Early Impact. Operative neurosurgery (Hagerstown, Md.), 26(2). pp. 156–164. 10.1227/ons.0000000000000901 Retrieved from

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Matthew Kelly

Associate Professor of Pediatrics

My research is broadly focused on elucidating the complex interactions that exist between the host microbiome and exogenous pathogens that cause infections in children. We have several ongoing projects evaluating: 1) the impact of the upper respiratory microbiome on the risk of colonization and invasion by bacterial respiratory pathogens among infants in Botswana; 2) associations between the gut microbiome of pediatric stem cell transplant recipients and the risk of infections (bloodstream infection, C. difficile infection) and graft-versus-host disease; and 3) the role of the gut and respiratory microbiomes in mediating COVID-19 infection susceptibility and disease severity in children. Ultimately, I aim to develop strategies that use targeted modification of the microbiome for the prevention of infections in children.

Peter Passias

Instructor in the Department of Orthopaedic Surgery

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