Hardware failure following multilevel posterior percutaneous fixation using the minimally invasive antepsoas (MIS-ATP) approach in adult spine deformity.

Background: Adult spinal deformities (ASDs) requiring long fusions to the lumbosacral junction are notorious for L5-S1 pseudarthrosis and hardware-related complications. The minimally invasive surgery antepsoas (MIS-ATP) technique allows for substantial anterior column reconstruction thereby reducing the risk of posterior hardware-related complications. This study investigates the incidence of posterior hardware-related complications following long-segment fusion (seven or more vertebrae) using MIS-ATP and posterior percutaneous fixation (PPF).

Methods: This is a retrospective review of patients who underwent long spinal fusion (MIS-ATP + PPF) to the sacrum and pelvis for the management of ASD between 2008 and 2019. Postoperative clinical complications and radiographic parameters were collected and analyzed. The following postoperative variables were collected: surgical site infections, neuro-vascular injuries, implant fracture, implant displacement, hardware prominence and related pain, pseudarthrosis, junctional disease (proximal and distal), and need for surgical revision.

Results: A total of 143 patients were included in this study. The most common indications for fusion included: degenerative scoliosis (76.9%) and degenerative spondylolisthesis (17.5%). The average number of fused vertebrae per individual was 8.7. The most common levels fused were: T12-S1 anterior/T10-S1 posterior (53.1%). Forty-four patients (30.8%) experienced a total of 48 complications: pseudarthrosis (2.1%), deep infections (4.2%), painful iliac hardware (5.6%), pedicle screw complications (6.3%), and proximal junctional disease (PJD) (9.8%). Of these, 30 patients (21%) required revision surgery, mostly due to PJD (8 patients; 5.6%).

Conclusions: Long spinal fusions to the sacrum and pelvis are technically challenging and notorious for hardware failure (HF) and revision surgeries. The use of MIS-ATP fusion coupled with PPF could provide a safe and effective strategy against posterior HF. Furthermore, additional benefits of the MIS-ATP technique are inherent to its relatively safe approach-related profile.