Scientific Articles   |    
Prognosis for Congenital Scoliosis Due to a Unilateral Failure of Vertebral Segmentation
Michael J. McMaster, MD, DSc, FRCS1; Marianne E. McMaster1
1 Department of Orthopaedic Surgery, Scottish National Spine Deformity Centre, Royal Hospital for Sick Children, Edinburgh, Scotland, UK EH9 1LF
View Disclosures and Other Information
  • Disclosure statement for author(s): PDF

Investigation performed at the Royal Hospital for Sick Children, Edinburgh, Scotland

Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. None of the authors, or their institution(s), have had any financial relationship, in the thirty-six months prior to submission of this work, with any entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. Also, no author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.

Copyright © 2013 by The Journal of Bone and Joint Surgery, Inc.
J Bone Joint Surg Am, 2013 Jun 05;95(11):972-979. doi: 10.2106/JBJS.L.01096
5 Recommendations (Recommend) | 3 Comments | Saved by 3 Users Save Case



Congenital scoliosis due to a unilateral failure of vertebral segmentation usually has a poor prognosis. However, not all curves progress to the same degree or develop the same spinal deformity.


The medical records and spine radiographs of 171 patients with a scoliosis due to unilateral unsegmented bar were reviewed retrospectively. The mean patient age at diagnosis was 9.3 years. Thirty-six patients had immediate surgery, 103 immature patients were followed untreated or before surgery for a mean duration of 3.6 years, twenty-eight patients were seen untreated at skeletal maturity, and four patients had no follow-up.


The unsegmented bar occurred at all levels; the mean extent was three vertebrae (range, two to eight vertebrae). Before the age of ten years, patients had a mean rate of scoliosis progression without treatment for all regions of the spine of 2° to 3° per year. By the age of ten years, seventy-three patients who had been seen untreated or prior to treatment had a mean scoliosis of 50° (range, 18° to 100°). After the age of ten years, these patients had an increase in the mean rate of scoliosis progression, but this rate varied per year depending on the affected region of the spine: 7° for the thoracolumbar curve, 5° for the midthoracic curve, and 4° for the upper thoracic curve. Spine surgery was performed on seventy-four patients who had a mean age of 12.2 years and a mean scoliosis of 78° for thoracolumbar curves, 66° for midthoracic curves, and 54° for upper thoracic curves. Of the patients with midthoracic congenital scoliosis, 24% developed a lower structural compensatory curve, which became larger and more deforming than the congenital curve, 22% had congenital rib fusions, and 16% had occult intraspinal anomalies.


Prognosis depends on growth imbalance at the site of the unsegmented bar as well as the location and extent of the bar, age at diagnosis, and spinal growth remaining.

Level of Evidence: 

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Figures in this Article
    Sign In to Your Personal ProfileSign In To Access Full Content
    Not a Subscriber?
    Get online access for 30 days for $35
    New to JBJS?
    Sign up for a full subscription to both the print and online editions
    Register for a FREE limited account to get full access to all CME activities, to comment on public articles, or to sign up for alerts.
    Register for a FREE limited account to get full access to all CME activities
    Have a subscription to the print edition?
    Current subscribers to The Journal of Bone & Joint Surgery in either the print or quarterly DVD formats receive free online access to JBJS.org.
    Forgot your password?
    Enter your username and email address. We'll send you a reminder to the email address on record.

    Forgot your username or need assistance? Please contact customer service at subs@jbjs.org. If your access is provided
    by your institution, please contact you librarian or administrator for username and password information. Institutional
    administrators, to reset your institution's master username or password, please contact subs@jbjs.org


    Accreditation Statement
    These activities have been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education (ACCME) through the joint sponsorship of the American Academy of Orthopaedic Surgeons and The Journal of Bone and Joint Surgery, Inc. The American Academy of Orthopaedic Surgeons is accredited by the ACCME to provide continuing medical education for physicians.
    CME Activities Associated with This Article
    Submit a Comment
    Please read the other comments before you post yours. Contributors must reveal any conflict of interest.
    Comments are moderated and will appear on the site at the discretion of JBJS editorial staff.

    * = Required Field
    (if multiple authors, separate names by comma)
    Example: John Doe

    Related Content
    The Journal of Bone & Joint Surgery
    JBJS Case Connector
    Topic Collections
    Related Audio and Videos
    PubMed Articles
    Clinical Trials
    Readers of This Also Read...
    JBJS Jobs
    New York - Icahn School of Medicine at Mount Sinai
    District of Columbia (DC) - Children's National Medical Center
    S. Carolina - Department of Orthopaedic Surgery Medical Univerity of South Carlonina
    W. Virginia - Charleston Area Medical Center