Risk Factor Analysis of Proximal Junctional Kyphosis after Surgical Treatment of Adult Spinal Deformity with Oblique Lateral Interbody Fusion

Yoshinao Koike; Yoshihisa Kotani; Hidemasa Terao; Norimasa Iwasaki

doi:10.31616/asj.2019.0341

Risk Factor Analysis of Proximal Junctional Kyphosis after Surgical Treatment of Adult Spinal Deformity with Oblique Lateral Interbody Fusion

Asian Spine J. 2021 Feb;15(1):107-116. doi: 10.31616/asj.2019.0341. Epub 2020 Jun 12.

Authors

Yoshinao Koike¹, Yoshihisa Kotani^{1

2}, Hidemasa Terao^{1

3}, Norimasa Iwasaki³

Affiliations

¹ Spine and Spinal Cord Center, Department of Orthopaedic Surgery, Steel Memorial Muroran Hospital, Muroran, Japan.
² Department of Orthopedic Surgery, Kansai Medical University Medical Center, Moriguchi, Japan.
³ Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan.

Abstract

Study design: A single-center retrospective study.

Purpose: To investigate the prevalence of proximal junctional kyphosis (PJK) and its risk factors after surgical treatment of adult spinal deformity (ASD) with oblique lateral interbody fusion (OLIF).

Overview of literature: Correction of ASD using OLIF has been developed because it is less invasive, and enables correction of severe deformities. Although PJK is a well-recognized complication after the correction of spinal deformity, few studies have evaluated the prevalence and risk factors for PJK after OLIF for ASD.

Methods: We reviewed 74 patients who underwent surgery for ASD. PJK was defined as a proximal junction sagittal Cobb angle exceeding 10°, and at least 10° greater than the preoperative measurement. We investigated the following as risk factors: age, sex, body mass index, medical history, number of fused segments, number of interbody fusions, number of OLIFs, number of osteotomies, level of upper instrumented vertebrae, lowest instrumented vertebrae, and radiographic parameters.

Results: The mean follow-up duration was 22.4 months and the mean age of the patients was 73.6 years. PJK was present in 19/74 patients (25.7%) and absent in 55/74 (74.3%). In the univariate analysis, those with PJK had a significantly higher proportion of patients with a history of vertebral compression fracture (7/19 patients [36.8%] vs. 6/55 patients [10.9%], p=0.027). Those with PJK had a significantly higher proportion of patients with fusion to the pelvis (18/19 patients [94.7%] vs. 34/55 patients [61.8%], p=0.016). According to the multivariate analysis, fusion to the pelvis was a significant risk factor for PJK.

Conclusions: Fusion to the pelvis was the most important risk factor for PJK. A history of vertebral compression fracture served as an additional risk factor for PJK. Clinicians should consider these factors before treating ASD patients with OLIF.

Keywords: Adult spinal deformity; Lateral lumbar interbody fusion; Oblique lateral interbody fusion; Proximal junctional failure; Proximal junctional kyphosis.