Predictive model for distal junctional kyphosis after cervical deformity surgery.

dc.contributor.author

Passias, Peter G

dc.contributor.author

Vasquez-Montes, Dennis

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Poorman, Gregory W

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Protopsaltis, Themistocles

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Horn, Samantha R

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Bortz, Cole A

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Segreto, Frank

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Diebo, Bassel

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Ames, Chris

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Smith, Justin

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LaFage, Virginie

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LaFage, Renaud

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Klineberg, Eric

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Shaffrey, Chris

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Bess, Shay

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Schwab, Frank

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ISSG

dc.date.accessioned

2023-06-20T15:39:57Z

dc.date.available

2023-06-20T15:39:57Z

dc.date.issued

2018-12

dc.date.updated

2023-06-20T15:39:56Z

dc.description.abstract

Background context

Distal junctional kyphosis (DJK) is a primary concern of surgeons correcting cervical deformity. Identifying patients and procedures at higher risk of developing this condition is paramount in improving patient selection and care.

Purpose

The present study aimed to develop a risk index for DJK development in the first year after surgery.

Study design/setting

This is a retrospective review of a prospective multicenter cervical deformity database.

Patient sample

Patients over the age of 18 meeting one of the following deformities were included in the study: cervical kyphosis (C2-7 Cobb angle>10°), cervical scoliosis (coronal Cobb angle>10°), positive cervical sagittal imbalance (C2-C7 sagittal vertical axis (SVA)>4 cm or T1-C6>10°), or horizontal gaze impairment (chin-brow vertical angle>25°).

Outcome measures

Development of DJK at any time before 1 year.

Methods

Distal junctional kyphosis was defined by both clinical diagnosis (by enrolling surgeon) and post hoc identification of development of an angle<-10° from the end of fusion construct to the second distal vertebra, as well as a change in this angle by <-10° from baseline. Conditional Inference Decision Trees were used to identify factors predictive of DJK incidence and the cut-off points at which they have an effect. A conditional Variable-Importance table was constructed based on a non-replacement sampling set of 2,000 Conditional Inference Trees. Twelve influencing factors were found; binary logistic regression for each variable at significant cutoffs indicated their effect size.

Results

Statistical analysis included 101 surgical patients (average age: 60.1 years, 58.3% female, body mass index: 30.2) undergoing long cervical deformity correction (mean levels fused: 7.1, osteotomy used: 49.5%, approach: 46.5% posterior, 17.8% anterior, 35.7% combined). In 2 years after surgery, 6% of patients were diagnosed with clinical DJK; however, 23.8% of patients met radiographic definition for DJK. Patients with neurologic symptoms were at risk of DJK (odds ratio [OR]: 3.71, confidence interval [CI]: 0.11-0.63). However, no significant relationship was found between osteoporosis, age, and ambulatory status with DJK incidence. Baseline radiographic malalignments were the most numerous and strong predictors for DJK: (1) C2-T1 tilt>5.33 (OR: 6.94, CI: 2.99-16.14); (2) kyphosis<-50.6° (OR: 5.89, CI: 0.07-0.43); (3) C2-C7 lordosis<-12° (OR: 5.7, CI: 0.08-0.41); (4) T1 slope minus cervical lordosis>36.4 (OR: 5.6, CI: 2.28-13.57); (5) C2-C7 SVA>56.3° (OR: 5.4, CI: 2.20-13.23); and (6) C4_Tilt>56.7 (OR: 5.0, CI: 1.90-13.1). Clinically, combined approaches (OR: 2.67, CI: 1.21-5.89) and usage of Smith-Petersen osteotomy (OR: 2.55, CI: 1.02-6.34) were the most important predictors of DJK.

Conclusions

In a surgical cohort of patients with cervical deformity, we found a 23.8% incidence of DJK. Different procedures and patient malalignment predicted incidence of DJK up to 1 year. Preoperative T1 slope-cervical lordosis, cervical kyphosis, SVA, and cervical lordosis all strongly predicted DJK at specific cut-off points. Knowledge of these factors will potentially help direct future study and strategy aimed at minimizing this potentially dramatic occurrence.
dc.identifier

S1529-9430(18)30190-6

dc.identifier.issn

1529-9430

dc.identifier.issn

1878-1632

dc.identifier.uri

https://hdl.handle.net/10161/28233

dc.language

eng

dc.publisher

Elsevier BV

dc.relation.ispartof

The spine journal : official journal of the North American Spine Society

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10.1016/j.spinee.2018.04.017

dc.subject

ISSG

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Cervical Vertebrae

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Thoracic Vertebrae

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Humans

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Kyphosis

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Postoperative Complications

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Osteotomy

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Incidence

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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

Predictive model for distal junctional kyphosis after cervical deformity surgery.

dc.type

Journal article

duke.contributor.orcid

Passias, Peter G|0000-0002-1479-4070|0000-0003-2635-2226

duke.contributor.orcid

Shaffrey, Chris|0000-0001-9760-8386

pubs.begin-page

2187

pubs.end-page

2194

pubs.issue

12

pubs.organisational-group

Duke

pubs.organisational-group

School of Medicine

pubs.organisational-group

Clinical Science Departments

pubs.organisational-group

Orthopaedic Surgery

pubs.organisational-group

Neurosurgery

pubs.publication-status

Published

pubs.volume

18

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