Instrumented fusion in the setting of primary spinal infection

The objective of this study is to investigate the morbidity and mortality associated with instrumented fusion in the setting of primary spinal infection.

A search was performed in the PubMed and Medline databases for clinical case series describing instrumented fusion in the setting of primary spinal infection between 2003 and 2013. The search was limited to the English language and case series including at least 20 patients. The primary outcome measure was postoperative infection (recurrent local infection) + surgical site infection (SSI); secondary outcome measures included reoperation rates, development of other complications, and perioperative mortality.

There were 26 publications that met the inclusion criteria, representing 931 patients with spondylodiscitis who underwent decompression, debridement, and instrumented fusion. Spinal infections occurred most commonly in the lumbosacral spine (39.1%) followed by the thoracic spine (27.1%). The most common microorganisms were Staphylococcus spp. After decompression, debridement, and instrumented fusion, the overall rate of postoperative infection was 6.3% (1.6% recurrent infection rate + 4.7% SSI rate). The perioperative complication rate was 15.4%, and the mortality rate was estimated at 2.3%. Reoperation for wound debridement, instrumentation removal, pseudoarthrosis, and/or progressive neurological deficit was performed in 4.5% of patients.

The findings in this literature review suggest that the addition of instrumentation in the setting of a primary spinal infection has a low local recurrent infection rate (1.6%). However, the combined risk of postoperative infection is 6.3% (recurrent infection + SSI), more than three-fold the current infection rate following instrumentation procedures for degenerative spine disease. Moreover, the addition of hardware does usher in complications such as instrumentation failure and pseudoarthrosis requiring reoperation.