Does Thoracic Hypokyphosis Matter in Lenke Type 1 Adolescent Idiopathic Scoliosis?

Steven D Glassman; Daniel J Sucato; Leah Y Carreon; James O Sanders; Michael G Vitale; Lawrence G Lenke

doi:10.1016/j.jspd.2012.09.001

Does Thoracic Hypokyphosis Matter in Lenke Type 1 Adolescent Idiopathic Scoliosis?

Spine Deform. 2013 Jan;1(1):40-45. doi: 10.1016/j.jspd.2012.09.001. Epub 2013 Jan 3.

Authors

Steven D Glassman¹, Daniel J Sucato², Leah Y Carreon³, James O Sanders⁴, Michael G Vitale⁵, Lawrence G Lenke⁶

Affiliations

¹ Norton Leatherman Spine Center, 210 East Gray Street, Suite 900, Louisville, KY 40202, USA.
² Department of Pediatric Orthopedic Surgery, Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas, TX 75219, USA.
³ Norton Leatherman Spine Center, 210 East Gray Street, Suite 900, Louisville, KY 40202, USA. Electronic address: leah.carreon@nortonhealthcare.org.
⁴ Department of Orthopaedics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Box 665, Rochester, NY 14642, USA.
⁵ Columbia University and New York Presbyterian Hospital, 600 W. 168th Street, 7th Floor, New York, NY 10032, USA.
⁶ Department of Orthopaedic Surgery, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8233, Saint Louis, MO 63110, USA.

PMID: 27927321
DOI: 10.1016/j.jspd.2012.09.001

Abstract

Study design: We analyzed a prospective cohort of Lenke 1ABC adolescent idiopathic scoliosis (AIS) patients based on differences in T5-T12 sagittal alignment.

Objective: Our objective was to determine whether patients with hypokyphotic scoliosis demonstrate unique characteristics in terms of baseline health status and response to surgery.

Background summary: Right thoracic AIS often presents as a hypokyphotic scoliosis, with rotatory deformity resulting in a diminution of the normal thoracic kyphosis. The perceived importance is indicated by the inclusion of a sagittal plane modifier within Lenke's classification system for AIS and studies examining reduction strategies to restore thoracic kyphosis.

Methods: We grouped patients based on thoracic kyphosis, measured from T5 to T12, as either less than 10° (hypokyphotic) or greater than or equal to 10° (normal/kyphotic). We used Student t test for independent samples to compare continuous variables between the hypokyphotic and normal/kyphotic groups.

Results: There was a significant difference in age between groups (mean age, 14.9 years in the hypokyphotic group versus 13.4 years in the normal/kyphotic group; p = .007). Differences in baseline health status measures were statistically significant but small. Hypokyphotic patients reported less pain than normal/kyphotic patients, with a mean Scoliosis Research Society (SRS) Pain score of 4.15 versus 4.03 (p = .044), better SRS Mental Domain scores (4.06 vs. 3.92; p = .026), and better SRS Total scores (3.92 vs. 3.83, p = .027). The hypokyphotic group also had better SRS Appearance (3.36 vs. 3.30) and Activity scores (4.20 vs. 4.13), but these differences did not reach statistical significance.

Conclusions: There were no differences in baseline or 2-year postoperative outcome scores in Lenke 1 AIS patients with hypokyphosis compared with patients with normal sagittal alignment. Maintenance of or restoration to normal kyphosis in hypokyphotic patients with Lenke 1 AIS may not improve clinical outcome compared with patients who remain lordotic after surgical correction.

Keywords: Adolescent idiopathic scoliosis; Health status; SRS-22; Sagittal alignment; Thoracic hypokyphosis; Thoracic lordosis.