Pelvic Obliquity Correction in Distraction-Based Growth Friendly Implants

Mathew Schur; Lindsay M Andras; Rajan Murgai; Ali A Siddiqui; Nicholas R Gonsalves; Paul D Sponseller; John B Emans; Michael G Vitale; David L Skaggs; Growing Spine Study Group; Children's Spine Study Group

doi:10.1016/j.jspd.2019.03.003

Pelvic Obliquity Correction in Distraction-Based Growth Friendly Implants

Spine Deform. 2019 Nov;7(6):985-991. doi: 10.1016/j.jspd.2019.03.003.

Affiliations

¹ Children's Orthopaedic Center, Children's Hospital Los Angeles, 4650 Sunset Blvd, Los Angeles, CA 90027, USA.
² Division of Pediatric Orthopaedics, Johns Hopkins Children's Center, 1800 Orleans St, Baltimore, MD 21287, USA.
³ Department of Orthopaedic Surgery, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA.
⁴ Columbia University Medical Center, Morgan Stanley Children's Hospital of New York - Presbyterian, 3959 Broadway, New York, NY 10032, USA.
⁵ Children's Orthopaedic Center, Children's Hospital Los Angeles, 4650 Sunset Blvd, Los Angeles, CA 90027, USA. Electronic address: dskaggs@chla.usc.edu.
⁶ Growing Spine Foundation, 555 East Wells Street, Suite 1100, Milwaukee, WI 53202, USA.
⁷ Children's Spine Study Group, P.O. Box 397, Valley Forge, PA 19481, USA.

PMID: 31732012
DOI: 10.1016/j.jspd.2019.03.003

Abstract

Design: Multicenter retrospective review.

Objective: To evaluate radiographic outcomes and complication rates of patients treated with distraction based implants and pelvic fixation with either screws (sacral-alar-iliac [SAI] screws or iliac screws) or hooks (S hook iliac fixation).

Summary of background data: Multiple options exist for pelvic fixation in distraction-based growing rod systems; however, limited comparative data are available.

Methods: Early-onset scoliosis (EOS) patients of all diagnoses with distraction-based implants that had pelvic fixation from 2000 to 2013 were reviewed from two EOS multicenter databases. Patients were divided into two groups by type of pelvic fixation: (1) screw group (SAI screws or iliac screws) or (2) S hooks. Exclusion criteria were as follows: index instrumentation ≥10 years old and follow up <2 years. A total of 153 patients met the inclusion criteria. Mean age at index surgery was 6.1 years (range 1.0-9.9 years) and mean follow-up was 4.9 years.

Results: Pelvic fixation in the 153 patients was as follows: screw group = 42 and S hook group = 111. When comparing patients with >20° of initial pelvic obliquity, the screw group had significantly more correction; mean 26° ± 13° for the screw group versus mean 17° ± 7° in the S hook group (p = .039). There was no significant difference in change in T1-S1 length (40 vs. 39 mm, p = .89) or correction of Cobb angle (30° vs. 24°, p = .24). The total complication rate for the screw group was 14% (6/42) versus 25% (28/111) in the S hook group, though this did not achieve significance (p = .25). The most common complications were device migration (13), implant failure (8), and implant prominence (4) for S hooks and implant failure (3), implant prominence (2), and device migration (1) for the screw group.

Conclusion: In distraction-based growth-friendly constructs, pelvic fixation with screws achieved better correction of pelvic obliquity than S hooks. Complications were almost twice as common with S hooks than screws, though this did not reach statistical significance.

Keywords: Complications; Distraction-based growth friendly implants; Early onset scoliosis; Lumbar lordosis; Pelvic obliquity.

Publication types

Comparative Study
Multicenter Study

MeSH terms

Bone Screws / adverse effects
Child
Child, Preschool
Follow-Up Studies
Humans
Ilium* / diagnostic imaging
Ilium* / surgery
Infant
Internal Fixators / adverse effects
Osteogenesis, Distraction* / instrumentation
Pelvic Bones* / anatomy & histology
Pelvic Bones* / diagnostic imaging
Pelvic Bones* / surgery
Postoperative Complications / epidemiology
Radiography / methods
Retrospective Studies
Sacrum / diagnostic imaging
Sacrum / surgery
Scoliosis* / diagnostic imaging
Scoliosis* / surgery
Surgical Instruments / adverse effects
Treatment Outcome