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Randomized Controlled Trial
. 2024 Feb 7;106(3):180-189.
doi: 10.2106/JBJS.23.00178. Epub 2024 Feb 7.

The Effect of Implant Density on Adolescent Idiopathic Scoliosis Fusion: Results of the Minimize Implants Maximize Outcomes Randomized Clinical Trial

A Noelle Larson  1 , David W Polly  2 , Paul D Sponseller  3 , Michael P Kelly  4 , B Stephens Richards  5 , Sumeet Garg  6 , Stefan Parent  7 , Suken A Shah  8 , Stuart L Weinstein  9 , Charles H Crawford 3rd  10 , James O Sanders  11 , Laurel C Blakemore  12 , Matthew E Oetgen  13 , Nicholas D Fletcher  14 , Walter K Kremers  15 , Michelle C Marks  16 , Ann M Brearley  17 , Carl-Eric Aubin  18 , Daniel J Sucato  5 , Hubert Labelle  7 , Mark A Erickson  6 ; the Minimize Implants Maximize Outcomes Study Group
Collaborators, Affiliations
Randomized Controlled Trial

The Effect of Implant Density on Adolescent Idiopathic Scoliosis Fusion: Results of the Minimize Implants Maximize Outcomes Randomized Clinical Trial

A Noelle Larson et al. J Bone Joint Surg Am. .

Abstract

Background: Severe adolescent idiopathic scoliosis (AIS) can be treated with instrumented fusion, but the number of anchors needed for optimal correction is controversial.

Methods: We conducted a multicenter, randomized study that included patients undergoing spinal fusion for single thoracic curves between 45° and 65°, the most common form of operatively treated AIS. Of the 211 patients randomized, 108 were assigned to a high-density screw pattern and 103, to a low-density screw pattern. Surgeons were instructed to use ≥1.8 implants per spinal level fused for patients in the high-implant-density group or ≤1.4 implants per spinal level fused for patients in the low-implant-density group. The primary outcome measure was the percent correction of the coronal curve at the 2-year follow-up. The power analysis for this trial required 174 patients to show equivalence, defined as a 95% confidence interval (CI) within a ±10% correction margin with a probability of 90%.

Results: In the intention-to-treat analysis, the mean percent correction of the coronal curve was equivalent between the high-density and low-density groups at the 2-year follow-up (67.6% versus 65.7%; difference, -1.9% [95% CI: -6.1%, 2.2%]). In the per-protocol cohorts, the mean percent correction of the coronal curve was also equivalent between the 2 groups at the 2-year follow-up (65.0% versus 66.1%; difference, 1.1% [95% CI: -3.0%, 5.2%]). A total of 6 patients in the low-density group and 5 patients in the high-density group required reoperation (p = 1.0).

Conclusions: In the setting of spinal fusion for primary thoracic AIS curves between 45° and 65°, the percent coronal curve correction obtained with use of a low-implant-density construct and that obtained with use of a high-implant-density construct were equivalent.

Level of evidence: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

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Conflict of interest statement

Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H763 ).

References

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