Pelvic obliquity correction in distraction based growing

spine constructs

Mathew Schur BA1, Lindsay M Andras MD1, Paul D Sponseller MD MBA2, John B Emans MD3, David L Skaggs MD MMM1, Growing Spine

Study Group

1.Children's Orthopaedic Center, Children's Hospital Los Angeles; 2.Department of Orthopaedic Surgery, Johns Hopkins Childrens Hospital, Johns Hopkins University; 3.Department of Orthopaedic Surgery,

Boston Children’s Hospital, Harvard Medical School

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ICEOS 2016

Disclosures

• Mathew Schur, BA – None • Lindsay M. Andras MD – Eli Lilly (c); Orthobullets (e) ; POSNA (f);

SRS (f)• Paul D. Sponseller MD, MBA – SRS (f); DePuy (a&e); Globus Medical

(e); JBJS (f); Oakstone Medical (e)• John B. Emans MD – JCO (f); Medtronic Sofamor Danek (b); Synthes

(b)• David L. Skaggs MD MMM – SRS & POSNA (a); Biomet (e); Grand

Rounds (b); Zipline Medical, Inc. (b & c); Medtronic (e); Johnson & Johnson (d); Wolters Kluwer Health - Lippincott Williams & Wilkins; Biomet Spine (e); Growing Spine Foundation (f); GSSG (f); JCO (f); Orthobullets (b), Spine Deformity (f)

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a. Grants/Research Support

b. Consultantc. Stock/Shareholderd. Speakers’ Bureaue. Other Financial

Support f. Board/Committee

member

Background

• The use of pelvic fixation in growing spine constructs allows for correction of the significant pelvic obliquity that can occur in patients with early-onset scoliosis (EOS)

• Multiple options exist to provide this fixation

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Objective

To determine if there is a difference in the correction of pelvic obliquity by different types of pelvic fixation

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Iliac screws S HooksSacral Alar Iliac Screws

Methods

• Neuromuscular, syndromic, and congenital EOS patients treated with bilateral distraction based implants with pelvic fixation from 1990 to 2013 were reviewed from a multicenter database.

• Patients were divided into groups by type of pelvic fixation

• Patients with less than 2 year follow-up or index instrumentation at ≥ 10 years of age were excluded

• Statistical significance analyzed via t-test

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Results

34 patients met the inclusion criteria:

• Iliac screws - 14 patients • Sacral-alar-iliac (SAI) screws – 6 patients• S hook fixation – 6 patients• S1 screws alone – 8 patients

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Results

Mean preoperative radiographic measurements• Cobb angle = 83 degrees• T1-S1 length = 250 mm• Pelvic obliquity = 16.6 degrees

Mean radiographic measurements at final follow-up• Cobb angle = 49 degrees• T1-S1 length = 320 mm• Pelvic obliquity = 7.5 degrees

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Results

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Type of pelvic fixation Number of patients

Preoperative pelvic

obliquity (degrees)

Postoperative pelvic obliquity

(degrees)

Percent correction

(%)

Iliac screws 14 20.6 ± 11.6 9.4 ± 6.7 54

S1 screws alone 8 15.3 ± 9.0 6.5 ± 6.1 57

SAI (± S1) screws 6 13.9 ± 18.3 3.0 ± 2.2 79

S hook iliac fixation 6 11.7 ± 7.3 8.9 ± 4.6 24

Discussion

• Overall, iliac screw, SAI screw, and S1 screw pelvic fixation achieved better correction of pelvic obliquity than S hooks

• No difference was found in the correction of Cobb angle or T1-S1 length

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ConclusionIn dual rod distraction based implants, pelvic

fixation with screws achieved better correction of pelvic obliquity than S hooks

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References

1. Moe JH, Kharrat K, Winter RB, et al. Harrington instrumentation without fusion plus external orthotic support for the treatment of difficult curvature problems in young children. Clin Orthop Relat Res 1984;185:35–45.

2. Akbarnia BA, Breakwell LM, Marks DS, et al. Dual growing rod technique followed for three to eleven years until final fusion: the effect of frequency of lengthening. Spine 2008;33:984–90.

3. Muharrem Y, and Olgun ZD. Growing rod concepts: state of the art. Eur Spine J. March 2013; 22(Suppl 2): 118-130.

4. Sponseller P, Yang, JS, Thompson GH, McCarthy RE, Emans JB, Skaggs DL, Asher MA, Yazici M, Poe-Kochert C, Kostial P, Akbarnia BA. Pelvic fixation of growing rods: Comparison of constructs. Spine. July 15 2009; 34(16): 1706-1710.

5. Brooks JT, Jain A, Perez-Grueso FS, Skaggs D, Thompson GH, Akbarnia BA, Sponseller PD. Paper #35: Pelvic anchor outcomes in growing rod constructs: An analysis of patients with a minimum of 4 years of postoperative follow-up. Spine Deformity. November 2014; 2(6): 512.

6. Protopsaltis T, Schwab F, Bronsard N, Smith JS, Klineberg E, Mundis G, Ryan DJ, Hostin R, Hart R, Burton D, Ames C, Shaffrey C, Bess S, Errico T, Lafage V. The T1 Pelvic Angle, a Novel Radiographic Measure of Global Sagittal Deformity, Accounts for Both Spinal Inclination and Pelvic Tilt and Correlates with Health-Related Quality of Life. J Bone Joint Surg Am. October 01 2014; 96(19): 1631-1640.

7. Thompson GH, Akbarnia BA, Campbell Jr. RM. Growing rod techniques in early-onset scoliosis. Journal of Pediatric Orthopaedics. April/May 2007; 27(3): 354-361.

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