Implant-Associated Infection of Long-Segment Spinal Instrumentation: A Retrospective Analysis of 46 Consecutive Patients

Abstract

Study design: This single-center retrospective study analyzed patients with an implant-associated infection of spinal instrumentation (four or more segments) treated between 2010 and 2018.

Purpose: This study aimed to investigate the treatment of implant-associated infections of long-segment spinal instrumentation and to define risk factors for implant removal.

Overview of literature: Implant-associated infection occurs in 0.7%-20% of spinal instrumentation. Significant blood loss, delayed reoperation, and use of effective antibiotics are reported risk factors for implant removal.

Methods: Patients with superficial infections not involving the implant were excluded. All patients received surgical and antibiotic treatments according to our interdisciplinary osteomyelitis board protocol. An infection was considered healed if a patient showed no signs of infection 1 year after termination of treatment. The patients were divided into an implant retention group and implant removal group, and their clinical and microbiological data were compared.

Results: Forty-six patients (27 women, 19 men) with an implant-associated infection of long-segment spinal instrumentation and mean age of 65.3±14.3 years (range, 22-89 years) were included. The mean length of the infected instrumentation was 6.5±2.4 segments (range, 4-13 segments). Implant retention was possible in 21 patients (45.7%); in the other 25 patients (54.3%), a part of or the entire implant required removal. Late infections were associated with implant removal, which correlated with longer hospitalization. Both groups showed high postoperative complication rates (50%) and high mortality rates (8.7%). In 39 patients (84.8%), infection was eradicated at a mean follow-up of 18.9±11.1 months (range, 12-60 months). Three patients (6.5%) were lost to follow-up.

Conclusions: Implant-associated infections of long-segment spinal instrumentations are associated with high complication and mortality rates. Late infections are associated with implant removal. Treatment should be interdisciplinary including orthopedic surgeons and clinical infectiologists.

Keywords: Deep surgical site infection; Implant-associated infection; Long-segmental spinal instrumentation; Spinal infection.

Fig. 1.

Radiological examination (X-ray) of the lumbar spine in the anterior-posterior and lateral views in standing position of a patient receiving implant removal but no re-instrumentation due to an implant-associated infection. (A, B) Anterior-posterior and lateral views are the preoperative radiological examinations and demonstrate noticeable pedicle screw loosening. (C) and (D) show radiological examinations directly after implant removal, showing no significant loss of the sagittal or coronal balance. (E) and (F) demonstrate the radiological examinations during the follow-up examination (15 months after implant removal). No significant loss of the sagittal or coronal balance compared with the pre- and directly postoperative radiological examinations could be identified.