MSK Validation Study (MSK)

Prediction of Postoperative Global Sagittal Alignment Using Musculoskeletal Modeling - Validation Study

Spinal posture and imbalance are known to be related to increased muscle expenditure, with narrow "cone of economy" of muscle effort defining the most comfortable postures. Therefore, it is hypothesized that predicting the posture of the lowest muscle effort available for a patient with a given spinal alignment and body properties will correspond to the posture the patient will most likely assume. Based on established musculoskeletal models, a model application was configured to allow prediction of this optimal posture. This study aims to assess the validity of this approach and the value of using biomechanical modeling for pre-operative planning.

Study Overview

• Status: Completed
• Conditions: Proximal Junctional Kyphosis; Spino-pelvic Alignment; Thoracolumbar Spinal Fusion

Detailed Description

The objective of this study is to validate a novel method of post-operative posture prediction - a full-body biomechanical model based on an established technology and physiological reasoning. Specifically, the model ability to predict postoperative global sagittal alignment, including compensatory and reciprocal changes, from pre-operative radiographic imaging and the information about planned posture correction will be evaluated. This will be realized by comparing model-predicted radiographic measures and overall balance to follow-up patient radiographs.

Having demonstrated model validity to predict postoperative posture will allow to use this method for simulating various "what-if" scenarios to empower surgical planning by predicting expected outcomes. This can be used to optimizing preoperative planning, which has a potential to substantially improved surgery predictability and patient outcomes.

Furthermore, validated model will allow scientific investigation of the principles governing human posture and biomechanics of the pathological spine. Generated scientific knowledge of biomechanical factors influencing sagittal posture and surgery outcomes (e.g. number of levels fused, amount and distribution of posture correction, etc.) can lead to improvements in clinical management of spinal disorders.

• Study Type: Observational
• Enrollment (Actual): 200

Contacts and Locations

Study Locations

• United States
  • Colorado
    • Aurora, Colorado, United States, 80045
      • University of Colorado
  • Pennsylvania
    • Pittsburgh, Pennsylvania, United States, 15213
      • Univerisity of Pittsburgh Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: N/A

• Sampling Method: Non-Probability Sample

Study Population

At least 186 patients will be enrolled in this multicenter combined observational / in silico study, recruited into 3 groups (at least 62 cases each) according to the number of levels instrumented:

1. local fusion, 1-2 segments;
2. short fusion, 3-4 segments;
3. long fusion, 5+ segments.

Description

Inclusion Criteria:

1. Male or female patients
2. Any ethnicity
3. At least 18 years of age
4. Has undergone a thoracolumbar spinal fusion procedure

Exclusion Criteria:

1. Patient has had a prior spinal surgery in the thoracic and/or lumbar spine;
2. Patient presents scoliosis greater or equal to 20° T4-T12 Cobb angle;
3. Patient has been diagnosed with idiopathic adolescent scoliosis (treated or untreated);
4. Patient has other implants that obstruct the spine and/or pelvis in the lateral view;
5. Patient presents any of the following complications: pseudoarthrosis, instrumentation failure, instrumentation pull-out and/or requires a revision surgery at any time following the primary surgery and prior to 3 months post-op;
6. Patient is a prisoner.

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference between model-predicted and observed postural measures - Thoracic Kyphosis (TK)	The simulation-predicted posture will be compared against the posture observed at follow-up, using the thoracic kyphosis (TK) angle.	3 months
Difference between model-predicted and observed postural measures - Lumbar Lordosis (LL)	The simulation-predicted posture will be compared against the posture observed at follow-up, using the LL - lumbar lordosis (LL) angle.	3 Months
Difference between model-predicted and observed postural measures - T1 Pelvic Angle (TPA)	The simulation-predicted posture will be compared against the posture observed at follow-up, using the T1 pelvic angle (TPA).	3 Months
Difference between model-predicted and observed postural measures - Pelvic Incidence-Lumbar Lordosis Mismatch (∆PILL)	The simulation-predicted posture will be compared against the posture observed at follow-up, using the pelvic incidence-lumbar lordosis mismatch (∆PILL).	3 Months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Model sensitivity and specificity in predicting posture imbalance	A McNemar's test (a paired Chi-squared test) will be used to test the null hypothesis that the balance prediction is due to chance, allowing to assess if the model predictive power is better than random.	3 months

Collaborators and Investigators

• Sponsor: NuVasive
• Investigators: Study Director: Kyle Malone, MS, NuVasive

Study record dates

Study Major Dates

• Study Start (Actual): May 15, 2020
• Primary Completion (Actual): October 1, 2022
• Study Completion (Actual): October 1, 2022

Study Registration Dates

• First Submitted: June 2, 2020
• First Submitted That Met QC Criteria: June 4, 2020
• First Posted (Actual): June 9, 2020

Study Record Updates

• Last Update Posted (Estimated): December 22, 2025
• Last Update Submitted That Met QC Criteria: December 16, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Spinal Diseases; Bone Diseases; Spinal Curvatures; Kyphosis
• Other Study ID Numbers: NUVA.MSK1901

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No