18F-FDG-PET/CT localizes intervertebral disc space infection following posterior lumbar interbody fusion surgery leading to successful retention of percutaneously inserted pedicle screws: a case report.

Introduction: Postoperative infection is a potentially devastating complication of spine surgery and an appropriate strategy and timely decision-making are essential for successful treatment of deep surgical site infection (SSI) after spinal instrumentation surgeries. However, there is a lack of consensus on implant removal or retention. We report on a case of deep SSI after posterior lumbar interbody fusion (PLIF) surgery in which we achieved clinical cure by debridement and removal of the interbody fusion cage without removing the percutaneously inserted pedicle screws (PPS).

Case presentation: A case was a 53-year-old woman with deep SSI after PLIF surgery using the PPS system at the L4-5 level. Computed tomography (CT) showed no clear radiolucent line around the screws and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET)/CT demonstrated abnormal FDG uptake around the cages and no uptake around the pedicle screws. Intervertebral cages were removed and iliac bone grafts were inserted between the vertebral bodies, without removing the pedicle screws. The infection was cleared and bone fusion was achieved after the revision surgery.

Discussion: Targeting active infection using FDG-PET/CT is considered useful in narrowing the surgical margins and determining whether to preserve instrumentation in revision surgery after SSI. PLIF using the PPS system could be useful in preventing the easy spread of infection from the intervertebral space to the insertion point of PPS through the interstitial space.