Hemoglobin Levels Pre- and Posttreatment as a Surrogate for Disease Severity in Early-Onset Scoliosis

Michael Glotzbecker; Patricia Miller; Michael Vitale; Leah DeWitt; Alexandra Grzywna; Jeffrey Sawyer; Joshua Pahys; Patrick Cahill; John Emans; Children's Spine Study Group

doi:10.1016/j.jspd.2018.11.002

Hemoglobin Levels Pre- and Posttreatment as a Surrogate for Disease Severity in Early-Onset Scoliosis

Spine Deform. 2019 Jul;7(4):641-646. doi: 10.1016/j.jspd.2018.11.002.

Authors

Michael Glotzbecker¹, Patricia Miller², Michael Vitale³, Leah DeWitt², Alexandra Grzywna², Jeffrey Sawyer⁴, Joshua Pahys⁵, Patrick Cahill⁶, John Emans²; Children's Spine Study Group

Affiliations

¹ Department of Orthopaedic Surgery, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA. Electronic address: Michael.Glotzbecker@childrens.harvard.edu.
² Department of Orthopaedic Surgery, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA.
³ Department of Orthopaedic Surgery, Morgan Stanley Hospital, 3959 Broadway, New York, NY 10032, USA.
⁴ Department of Orthopaedic Surgery, Campbell Clinic Orthopaedics, 1211 Union Ave Suite 500, Memphis, TN 38104, USA.
⁵ Department of Orthopaedic Surgery, Shriners Hospital for Children, 3551 N Broad St, Philadelphia, PA 19140, USA.
⁶ Department of Orthopaedic Surgery, Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104, USA.

PMID: 31202383
DOI: 10.1016/j.jspd.2018.11.002

Abstract

Study design: Prospective cohort.

Objective: To compare preoperative hemoglobin levels to postoperative hemoglobin levels in patients with early-onset scoliosis (EOS).

Summary of background data: Elevated hemoglobin (Hgb) may be a marker for preoperative hypoxia in patients with EOS and thoracic insufficiency syndrome (TIS). The changes in Hgb level after treatment may be a surrogate marker for improved oxygenation.

Methods: Because normal levels of Hgb vary with patient age, Hgb z scores were calculated by dividing age-adjusted mean Hgb levels by the age-adjusted standard deviation. Elevated Hgb was defined by a hemoglobin z score >1. Patients with a baseline Hgb value measured before initial implantation with at least one follow-up measurement, at 6, 12, or 18 months, were included in longitudinal analysis. Change in Hgb z score as well as change in curve magnitude over time was assessed using piecewise linear mixed modeling for patients with elevated Hgb and those without.

Results: Two hundred sixty-seven patients with EOS were treated surgically over the study period. Average age at initial implantation was 6.8 years. Forty-eight (18%; 95% confidence interval = 13.7%, 23.2%) subjects had an elevated Hgb (z score > 1) level before implantation procedure. Hgb levels decreased in subjects with elevated Hgb from implantation to 6 months (p < .001) with no change in Hgb from 6 to 12 months (p = .46) or from 12 to 18 months (p = .59), but an overall decrease from preoperative to 18 months (p < .001). There was no change in Hgb levels for subjects without elevated Hgb from implantation to 6 months (p = .94), from 6 to 12 months (p = .61), or from 12 to 18 months (p = .78).

Conclusions: In some patients with EOS and TIS, there appears to be significant positive impact on oxygenation from distraction instrumentation as evidenced by a meaningful proxy measurement: improvement in abnormal preoperative Hgb levels after surgery.

Level of evidence: III.

Keywords: EOS; Early Onset Scoliosis; Hemoglobin; Pulmonary function.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Child
Child, Preschool
Female
Hemoglobins / analysis*
Humans
Hypoxia / diagnosis
Hypoxia / etiology
Male
Prospective Studies
Respiratory Function Tests
Scoliosis* / blood
Scoliosis* / complications
Scoliosis* / epidemiology
Scoliosis* / surgery
Severity of Illness Index
Treatment Outcome

Substances

Hemoglobins