Medical Student University of Arizona College of Medicine - Phoenix Phoenix, Arizona, United States
Introduction: Hardware failure (HF) is a common risk in patients who undergo instrumented spine surgery. To our knowledge, there is a paucity of information regarding the timing of presentation, revision surgery, and outcomes of patients with HFs after spine surgery. The aim of this study was to investigate the incidence, temporal trends, and characteristics of HFs after spine surgery.
Methods: A systematic search of Pubmed was performed for articles relevant to the management of HF after spine surgery. Search terms used were: hardware, failure, rod, screw, break, loose, instrumentation and spine surgery. Data was extracted from select publications.
Results: Ten studies, identifying a total of 14588 patients with an average age of 56.7, were selected for final review. The overall incidence of HF was 1% (134 patients) with screw loosening demonstrating the greatest incidence (6.1%). The time to diagnose a HF ranged from 1 week to about 7.8 years after the index procedure, with cage subsidence, screw plowing, distal junctional failure and screw loosening occurring in ≤ 3 months and rod breakage and pseudoarthrosis after 20 months. The rate of revision surgery for HF was 65% (Table 1). A figure was developed to visually demonstrate the timeline of each hardware failure’s time to failure and average time to failure (figure 1). A new classification system (Table 2) was also developed to assist with clinical indications and timing for surgery based on symptoms, radiographic evidence, type of failure, and spine stability.
Conclusion : This work introduces a new classification of hardware failures and delineates the nature and timing to failure. The four classes are: Incidental and asymptomatic, incidental and likely needs revision, symptomatic and needs revision electively, and symptomatic and needs urgent revision.
