The diagnosis and management of infection following instrumented spinal fusion

Abstract

A 10-year retrospective audit. (1) The incidence of infection; (2) causative organisms; (3) whether eradication of infection is achievable with spinal implant retention; (4) patient outcome. The reported incidence of infection following posterior spinal instrumentation is between 2.6 and 3.8%. Management of infection is controversial, with some advocating serial wound debridement while others report that infection cannot be eradicated with retention of implants. There are no published data demonstrating that propionibacteria are associated with early postoperative infection. The management of infected cases at our institution includes eventual removal of their implants. Our population was identified by studying the case notes of all patients who had undergone removal of spinal implants and cross-referencing this population with positive microbiology or histology reports. The incidence of infection was 3.7%. Propionibacteria were isolated in 45% of cases. The diagnosis of infection was unexpected in 25% of patients, following removal of implants for prominence of implants or back pain. Sixty per cent of patients with acute postoperative deep wound infection had continuing active infection on subsequent removal of implants, despite long-term antibiotics and wound debridement. Fourty-six per cent of patients had a stable, pain-free spine at the end of their treatment. This is the largest reported series of infections following posterior spinal instrumented fusions of which we are aware. Propionibacteria are a common cause of infection and successful eradication of infection cannot be reliably achieved with antibiotics and wound debridement alone.

Infections in spinal instrumentation

“…Pull ter Gunne et al [12] found that wound drainage was the most frequently seen sign indicating SSI and was present in 67.9% of deep SSI and 64.6% of isolated superficial SSI. In the study of Collins et al [11], the mean time for infection diagnosis was 14 months (days to years postoperatively); 24.3% were detected or more years after initial surgery. These demonstrate the need for longterm follow-up following instrumented spinal surgery in order to obtain a more accurate indication of the incidence of infection.…”

“…After closure, the appropriate antibiotics are administered for two to six weeks [4,[42][43][44][45][46]. Collins et al [11] reported that nine (40%) of 15 patients treated with antibiotic therapy and wound debridement with implant retention had an active infection at the time of implant removal despite antibiotic therapy. Infection could not always be eradicated with implant retention.…”

“…Mean Physical Component Summary was 41.4 in the infection group and 44.3 in the control group (P00.6). Collins et al [11] found poorer outcomes, reporting that only 46% of patients had stable pain free spines when implants were removed in established fusions.…”

Postoperative Complications of Suction Drain in Patients Submitted to 1-Level Lumbar Arthrodesis

“…Infection of the surgical site is one of the most commonly observed complications in spine surgery, occurring in 2.2% to 8.5% of cases where instrumentation is required. 17,18 Some studies have shown procedure infection rates that reach as high as 20%. 19 In this study we observed infection in 5% (two superficial and one deep) of the total number of surgeries performed, two recorded in the group using a drain and one in the group not using a drain, with the beginnings of this complication seen on the 14th day after surgery.…”

Infections associated with spinal implants

“…Consideration should also be given to identifying potential infections by nasal swabs and the use of antibiotic nasal ointment, wound lavage with normal saline or with normal saline and antibiotic [39]. More chronic infections have been shown to be associated with propionibacterium acnes [40,43].…”