P93. Semitendinosus ligament reinforcement for prevention of proximal junctional kyphosis and failure in adult spinal deformity

Abstract

BACKGROUND CONTEXT Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) are well-recognized, but incompletely understood complications that can occur following posterior spinal fusion in adult deformity surgery. PJK prevention techniques have the potential to decrease morbidity by reducing eventual development of PJF. In this study we sought to describe the clinical results of a novel technique for interspinous ligament augmentation using a semitendinosus allograft. PURPOSE To assess the incidence of PJK and PJF after augmenting the uppermost instrumented vertebra (UIV) with a semintendinous allograft in patients undergoing complex spinal deformity surgery. STUDY DESIGN/SETTING Single institution retrospective review of a case series. PATIENT SAMPLE Consecutive series of adult spinal deformity patients at a single institution treated by two surgeons between 2015-2017. OUTCOME MEASURES Oswestry Disability Index (ODI), Proximal Junctional Kyphosis, Proximal Junctional Failure, Pelvic Incidence, Pelvic Tilt, Lumbar Lordosis, PI-LL Mismatch, Sagittal Vertical Axis (SVA), Thoracic Kyphosis, T1 Sagittal Tilt, UIV + 2 Sagittal Cobb Angle. METHODS Allograft ligament augmentation was used in a consecutive series of adult spinal deformity patients at a single institution by two surgeons between 2015-2017. Patient demographics, surgical details, ODI scores and complications were recorded. Preoperative and postoperative spinopelvic parameters were measured. PJK was defined as a sagittal Cobb angle between the uppermost instrumented vertebra (UIV) and two levels above the UIV (UIV +2) ≥10°and ≥10°compared to the preoperative measurement. PJF was defined as proximal junctional fracture, fixation failure, symptomatic PJK, or requiring revision of fusion within 1 year of surgery. Preoperative and postoperative ODI scores and spinopelvic parameters were compared using a Student's t-test. RESULTS A total of 48 patients (71% female, mean age 63 years) were included with average follow-up of 10.4 months. The UIV was most commonly upper thoracic (T2-T4) (60%) or T10 (38%). Sixty percent of cases were revision surgeries and 87.5% required osteotomies. Average ODI improved from 60% preoperatively to 40% at final follow-up (P CONCLUSIONS Interspinous ligament augmentation using a semitendinosus allograft represents a novel technique for the potential prevention of PJF. In this case series of patients at high risk for developing PJF, only 1 (2.1%) required a revision surgery for PJF. The use of this novel technique to reinforce the interspinous ligament may be considered in patients undergoing adult spinal deformity surgery at high risk for developing PJF. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.