Offset sublaminar hook is an efficient tool for the prevention of distal junctional failure after kyphotic deformity correction.

Abstract

Purpose: To assess the radiological outcomes and complications focusing on distal junctional failure (DJF) of adult spinal deformity patients who underwent thoracolumbar fixation with the use of offset sublaminar hooks (OSH) distally.

Methods: Retrospective review of a prospective, multicenter adult spinal deformity database (2 sites). Inclusion criteria were age of at least 18 years, presence of a spinal deformity with thoraco-lumbar instrumentation ending distally with OSH (pelvis excluded), with minimum 2 years of follow-up. Demographic data, spinopelvic parameters, functional outcomes and complications were collected. Data was analyzed using descriptive statistics. Statistical significance was set to p < 0.05.

Results: 32 patients met the inclusion criteria, with the main etiologies being Scheuermann kyphosis and post-traumatic kyphosis. There was a significant correction of thoracic or thoraco-lumbar kyphosis (from 83° to 45° in case of posterior column osteotomy, p < 0.001, and from 49° to 11° in case of a three-column osteotomy, p < 0.001). DJF occurred in 9.3% of the patients including 1 patient who presented distal hook dislodgement and 2 patients who presented a compression fracture below the lowest instrumented vertebra. Oswestry Disability Index score improved in the majority of the patients (from 34.3 to 18.1, p < 0.05).

Conclusions: This is the first paper to propose offset sublaminar hook as a safe and efficient tool for protection of the distal end of the construct in kyphotic ASD surgery when not going down to the pelvis. It showed satisfactory radiological and clinical outcome with an acceptable rate of complications and no distal junctional failure that required revision surgery.