Use of the kickstand rod improves coronal alignment and maintains correction compared to control at 2 year follow-up.

Purpose: To assess and compare coronal alignment correction at 2 year follow-up in adult spinal deformity (ASD) patients treated with and without the kickstand rod (KSR) construct.
Methods: ASD patients who underwent posterior spinal fusion at a single-center with a preoperative coronal vertical axis (CVA) ≥ 3 cm and a minimum of 2 year clinical and radiographic follow-up were identified. Patients were divided into two groups: those treated with a KSR and those who were not. Patients were propensity score-matched (PSM) controlling for preoperative CVA and instrumented levels to limit potential biases that my influence the magnitude of coronal correction.
Results: One hundred sixteen patients were identified (KSR = 42, Control = 74). There were no statistically significant differences in patient characteristics (p > 0.05). At baseline, the control group presented with a greater LS curve (29.0 ± 19.6 vs. 21.5 ± 10.8, p = 0.0191) while the KSR group presented with a greater CVA (6.3 ± 3.6 vs. 4.5 ± 1.8, p = 0.0036). After 40 PSM pairs were generated, there were no statistically significant differences in baseline patient and radiographic characteristics. Within the matched cohorts, the KSR group demonstrated greater CVA correction at 1 year (4.7 ± 2.4 cm vs. 2.9 ± 2.2 cm, p = 0.0012) and 2 year follow-up (4.7 ± 2.6 cm vs. 3.1 ± 2.6 cm, p = 0.0020) resulting in less coronal malalignment one (1.5 ± 1.3 cm vs. 2.4 ± 1.6 cm, p = 0.0056) and 2 year follow-up (1.6 ± 1.0 vs. 2.5 ± 1.5 cm, p = 0.0110). No statistically significant differences in PROMs, asymptomatic mechanical complications, reoperations for non-mechanical complications were observed at 2 year follow-up. However, the KSR group experienced a lesser rate of mechanical complications requiring reoperations (7.1% vs. 24.3%. OR = 0.15 [0.03-0.72], p = 0.0174).
Conclusions: Patients treated with a KSR had a greater amount of coronal realignment at the 2 year follow-up time period and reported less mechanical complications requiring reoperation. However, 2 year patient-reported outcomes were similar between the two groups.
Competing Interests: Declarations. Competing interests: Fthimnir Hassan, Anson Bautista, Justin Reyes, Varun Puvanesarajah, Josephine Coury, and Sarthak Mohanty have no relevant financial or non-financial interests to disclose. Lawrence G. Lenke has received grant support from AO Spine, International Spine Summit Group, Scoliosis Research Society, EOS Technology and Setting Scoliosis Straight Foundation as a study investigator. Ronald A. Lehman has received grant support from the Department of Defense as a study investigator. Zeeshan M. Sardar, Joseph M. Lombardi, Ronald A. Lehman, and Lawrence G. Lenke have received consulting fees from Medtronic. Lawrence G. Lenke has received consulting fees from Acuity Surgical and Abryx. Lawrence G. Lenke has received reimbursements from Broadwater, AO Spine, and Scoliosis Research Society for attending meetings/travel. Ronald A. Lehman and Lawrence G. Lenke have received royalties and are patent holders from Medtronic. Ronald A. Lehman has received royalties and is a patent holder from Stryker. Joseph M. Lombardi has received consulting fees from Stryker. Ethical approval: AAAR6015. This retrospective chart review study involving human participants was in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The Human Investigation Committee (IRB) of Columbia University Irving Medical Center approved this study. Informed consent: Informed consent was obtained from all individual participants included in the study.
(© 2024. The Author(s), under exclusive licence to Scoliosis Research Society.)