Dynamic changes of the pelvis and spine are key to predicting postoperative sagittal alignment after pedicle subtraction osteotomy: a critical analysis of preoperative planning techniques.

dc.contributor.author

Smith, Justin S

dc.contributor.author

Bess, Shay

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Shaffrey, Christopher I

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Burton, Douglas C

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Hart, Robert A

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Hostin, Richard

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Klineberg, Eric

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International Spine Study Group

dc.date.accessioned

2023-08-30T00:21:56Z

dc.date.available

2023-08-30T00:21:56Z

dc.date.issued

2012-05

dc.date.updated

2023-08-30T00:21:55Z

dc.description.abstract

Study design

Retrospective, radiographical analysis of mathe-matical formulas used to predict sagittal vertical axis (SVA) after pedicle subtraction osteotomy (PSO).

Objective

Evaluate the ability of different formulas to predict SVA after PSO.

Summary of background data

Failure to achieve optimal spinal alignment after spinal fusion correlates with poor outcomes. Numerous mathematical models have been proposed to aid preoperative PSO planning and predict postoperative SVA. Pelvic parameters have been shown to impact spinal alignment; however, many preoperative planning models fail to evaluate these. Compensatory changes within unfused spinal segments have also been shown to impact SVA. Predictive formulas that do not evaluate pelvic parameters and unfused spinal segments may erroneously guide PSO surgery. A formula that integrates pelvic tilt (PT) and spinal compensatory changes to predict optimal SVA has been previously proposed.

Methods

Comparative analysis of 5 mathematical models used to predict optimal postoperative SVA (<5 cm) after PSO was performed using a multicenter PSO database.

Results

Radiographs of 147 patients, mean age 52 years (SD = 15 yr), who received 147 PSOs (42 thoracic and 105 lumbar) were evaluated. Mean preoperative and postoperative SVA was 108 mm (SD = 95 mm) and 30 mm (SD = 60 mm; P < 0.001), respectively. Each mathematical formula provided unique prediction for postoperative SA (Pearson R < 0.15). Formulas that neglected pelvic alignment poorly predicted final SVA and poorly correlated with optimal SVA. Formulas that evaluated pelvic morphology (pelvic incidence) had improved SVA prediction. The Lafage formulas, which incorporate PT and spinal compensatory changes, had the best SVA prediction (P < 0.05) and best correlation with optimal SVA (R = 0.75).

Conclusion

Preoperative planning for PSO is essential to optimize postoperative spinal alignment. Mathematical models that do not consider pelvic parameters and changes in unfused spinal segments poorly predict optimal postoperative alignment and may predispose to poor clinical outcomes. The Lafage formulas, which incorporated PT and spinal compensatory changes, best predicted optimal SVA.
dc.identifier.issn

0362-2436

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1528-1159

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https://hdl.handle.net/10161/28868

dc.language

eng

dc.publisher

Ovid Technologies (Wolters Kluwer Health)

dc.relation.ispartof

Spine

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10.1097/brs.0b013e31823b0892

dc.subject

International Spine Study Group

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Pelvis

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Spine

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Humans

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Radiography

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Treatment Outcome

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Preoperative Care

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Osteotomy

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Postoperative Period

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Retrospective Studies

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Predictive Value of Tests

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Adult

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Aged

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Middle Aged

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Female

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Male

dc.title

Dynamic changes of the pelvis and spine are key to predicting postoperative sagittal alignment after pedicle subtraction osteotomy: a critical analysis of preoperative planning techniques.

dc.type

Journal article

duke.contributor.orcid

Shaffrey, Christopher I|0000-0001-9760-8386

pubs.begin-page

845

pubs.end-page

853

pubs.issue

10

pubs.organisational-group

Duke

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School of Medicine

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Clinical Science Departments

pubs.organisational-group

Orthopaedic Surgery

pubs.organisational-group

Neurosurgery

pubs.publication-status

Published

pubs.volume

37

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