CLINICAL ARTICLE J Neurosurg Spine 28:512–519, 2018 P roximal junctional kyphosis (PJK) is a well-rec- ognized, yet incompletely defned, complication in patients undergoing instrumented fusion for spinal deformity. The condition most commonly presents with abnormal kyphosis immediately above the upper instru- mented vertebra (UIV). The angle of kyphosis is mea- sured using the sagittal Cobb angle between the inferior endplate of the UIV and superior endplate of the second vertebral body above the UIV (UIV+2). The defnition of PJK varies in the literature, and some suggest that PJK ABBREVIATIONS PJA = proximal junctional angle; PJF = proximal junctional failure; PJK = proximal junctional kyphosis; UIV = upper instrumented vertebra. SUBMITTED January 4, 2017. ACCEPTED September 19, 2017. INCLUDE WHEN CITING Published online February 23, 2018; DOI: 10.3171/2017.9.SPINE1710. * M.M.S. and V.D. contributed equally to this work. Ligament augmentation for prevention of proximal junctional kyphosis and proximal junctional failure in adult spinal deformity *Michael M. Safaee, MD, 1 Vedat Deviren, MD, 2 Cecilia Dalle Ore, BA, 1 Justin K. Scheer, MD, 3 Darryl Lau, MD, 1 Joseph A. Osorio, MD, PhD, 1 Fred Nicholls, MD, 4 and Christopher P. Ames, MD 1,2 Departments of 1 Neurological Surgery and 2 Orthopedic Surgery, University of California, San Francisco, California; 3 Department of Neurological Surgery, University of Illinois, Chicago, Illinois; and 4 Department of Orthopedic Surgery, University of Calgary, Alberta, Canada OBJECTIVE Proximal junctional kyphosis (PJK) is a well-recognized, yet incompletely defned, complication of adult spinal deformity surgery. There is no standardized defnition for PJK, but most studies describe PJK as an increase in the proximal junctional angle (PJA) of greater than 10° –20° . Ligament augmentation is a novel strategy for PJK reduction that provides strength to the upper instrumented vertebra (UIV) and adjacent segments while also reducing junctional stress at those levels. METHODS In this study, ligament augmentation was used in a consecutive series of adult spinal deformity patients at a single institution. Patient demographics, including age; sex; indication for surgery; revision surgery; surgical approach; and use of 3-column osteotomies, vertebroplasty, or hook fxation at the UIV, were collected. The PJA was measured preoperatively and at last follow-up using 36-inch radiographs. Data on change in PJA and need for revision surgery were collected. Univariate and multivariate analyses were performed to identify factors associated with change in PJA and proximal junctional failure (PJF), defned as PJK requiring surgical correction. RESULTS A total of 200 consecutive patients were included: 100 patients before implementation of ligament augmenta- tion and 100 patients after implementation of this technique. The mean age of the ligament augmentation cohort was 66 years, and 67% of patients were women. Over half of these cases (51%) were revision surgeries, with 38% involving a combined anterior or lateral and posterior approach. The mean change in PJA was 6° in the ligament augmentation group compared with 14° in the control group (p < 0.001). Eighty-four patients had a change in PJA of less than 10° . In a multivariate linear regression model, age (p = 0.016), use of hook fxation at the UIV (p = 0.045), and use of ligament augmentation (p < 0.001) were associated with a change in PJA. In a separate model, only ligament augmentation (OR 0.193, p = 0.012) showed a signifcant association with PJF. CONCLUSIONS Ligament augmentation represents a novel technique for the prevention of PJK and PJF. Compared with a well-matched historical cohort, ligament augmentation is associated with a signifcant decrease in PJK and PJF. These data support the implementation of ligament augmentation in surgery for adult spinal deformity, particularly in patients with a high risk of developing PJK and PJF. https://thejns.org/doi/abs/10.3171/2017.9.SPINE1710 KEY WORDS proximal junctional kyphosis; proximal junctional failure; spinal deformity; ligament augmentation J Neurosurg Spine Volume 28 • May 2018 512 ©AANS 2018, except where prohibited by US copyright law Unauthenticated | Downloaded 05/11/22 04:51 AM UTC