Surgeons should consider removal or replacement of implants following adult spinal deformity (ASD) surgery only in cases where there is recurrent infection or evidence of osteolysis—but rarely in the case of initial acute infections. This was the message from Ali Baaj (spinal neurosurgeon, Weill Cornell Medicine, New York Presbyterian Hospital, New York, USA), at the 5th Annual International Spinal Deformity Symposium (ISDS 2019; 5–7 December; New York, USA) who spoke on the subject of infection management in spinal deformity patients.
During his presentation, Baaj noted that current literature suggests that there is an incidence of infection in ASD patients between 6.2–14.8%. Around 6% of ASD patients, he noted, experience deep wound infections, while the readmission rate within 90 days stands at around 10.9%. Baaj outlined common risk factors for infection, which include advanced age, BMI, prior surgery, whether or not they have had a 3-column osteotomy, whether they are diabetic, the operation time and whether or not they are a smoker. “Everybody would agree that the vast majority of adult deformity patients would have, if not all of these risk factors, most of these risk factors. So we know that these are high risk patients to begin with,” he commented.
Turning to the microbiology of infections in ASD patients, he classified infections as being either ‘acute’ (manifesting within three months of procedure) or ‘delayed’ (arising three months and onwards). “Everybody easily identifies the acute infections,” he said. “We know it is usually a staph species, we know what it looks like.” However, Baaj identified delayed infections as an area of greater concern, noting that they can be harder to diagnose. “Something is probably brewing underneath,” he commented, “and that is usually P.acnes or some gram negative bacteria.”
Baaj advocated the use of Vancomycin powder in preventing infection, commenting that studies and practical evidence have shown that its use has improved infection rates. He also encouraged attendees to consider the use of plastics surgery closure to promote healing. “We employ plastics closure for all complex instrumented cases, all revision cases, oncology cases. We have found that the infection rates and the wound dehiscence rates have decreased significantly,” he said. Furthermore he commented that while minimally invasive procedures have been found to yield lower infection rates, these surgeries are typically carried out for less severe deformities.
Offering up practical advice based on recent literature and anecdotal evidence, Baaj posited that for acute infections, “debridement and antibiotics is really the standard,” adding: “You do not need to remove the hardware.”
Concluding the presentation, Baaj noted that it is important to warn patients of the high risk of infection prior to ASD surgery. He said: “Infections are common, you have to tell the patients. The number one complication is infection for sure.”
He added: “You can leave the hardware in for acute staph infections, I think everybody agrees with that, but you have to consider taking out the hardware if you have recurrent infections or evidence of osteolysis, barring instability.
“If you are getting a CT, and the screws are loosening, it is a recurrent infection, you have got to take out the hardware. If you feel that there is instability, or you are worried about the loss of correction, you may consider replacing them.”