Deep wound infection following pediatric scoliosis surgery: incidence and analysis of risk factors

Deep wound infection after surgery for scoliosis correction is a severe complication that requires prolonged medical and surgical management.1 It is defined as a surgical site infection in which there is a direct communication between the associated infected material and the spinal instrumentation and bone graft/fusion mass.1–4 Infection can occur early or late, with signs of late infection appearing at an average of 3.1 (range 1.2–8.5) years postoperatively.5,6 The incidence of postoperative wound infection in patients with idiopathic scoliosis ranges from 1% to 5%, with the reported incidence being highly variable.1,5,7–9 By contrast, in patients with neuromuscular causes of scoliosis the rate is much higher, ranging from 4%–14% in some studies.1,4,10–13 Impaired immune status, poor personal hygiene and soiling of the wound have been suggested to contribute to the higher incidence of infection in patients with neuromuscular disorders.4 Other suggested risk factors include a higher degree of cognitive impairment,1 malnourishment,1,14 prolonged duration of surgery, large volumes of instrumentation and the presence of another remote infectious lesion.15 The use of allograft has also been suggested to increase the risk of infection, but this conclusion remains controversial.4,16,17 The diagnosis of infection is difficult to establish but is suggested by pain,18 the presence of a sinus tract, persistent or late postoperative wound drainage, erythema, wound dehiscence, positive culture from a wound aspirate, instrumentation failure/pseudoarthrosis and pathologic confirmation of the presence of inflammatory cells and/or the offending organism(s).1,3,5,6,19 Staphylococcus aureus1,12,15 and S. epidermidis2,5,20 have been reported to be the most common causative organisms. A high erythrocyte sedimentation rate (ESR) has also been reported to be associated with late infection.20 There is a substantial patient cost associated with the development of deep wound infection following scoliosis surgery. It can compromise the outcome of the deformity correction; especially in patients who require subsequent removal of the implants for effective eradication of the infectious agents.1 Other associated complications, including the development of sepsis, vertebral osteomyelitis, neurologic compromise and clinically important soft tissue defects, are additional sources of patient morbidity that in some cases may be life-threatening.1 As such, the identification of risk factors associated with the development of deep wound infection is paramount to develop measures to help prevent this devastating complication. To this end, the aim of our study was 2-fold: first, we sought to determine the incidence of deep wound infection following pediatric scoliosis surgery, and second, we sought to identify significant risk factors predisposing these patients to infection.