[Infections in surgery of idiopathic scoliosis]

In this retrospective study, we evaluated infectious complications in the patients undergoing surgical treatment for idiopathic scolions in order to identify risk factors for postoperative infections.

A total of 786 patients with idiopathic scoliosis were operated on during 24 years. In 754 (96%) cases, we used the posterior approach, involving posterior fusion and internal fixation, and subsequent immobilization in a brace. During that period, we recorded 15 (1.9%) deep wound infections in the area of fusion. Early infections were treated by debridement and lavage, with targeted administration of antibiotics, while instrumentation was kept in place. In late und recurrent infections, instrumentation was always removed.

We investigated a relationship between the infectious agent and the device used, the length of period between surgery and the onset of infection, the effect of device removal on curve progression, the agent causing infection and the effect of allergy to metal or infectious lesions at other body sites on the outbreak of infection.

Early infections (within 6 weeks) were observed in six, late in nine patients. Repeat operations were necessary on average after 487 days. Staphylococcus aureus, the most frequent infectious agent, was isolated from four patients; on four occasions, cultivation was negative. Allergy to nickel was found in four patients. Infection was most often associated with the most frequently used Harrington Instrumentation (six cases, 1.1%). However, in relation to the number of patients treated, infection frequency was highest in TSRH (5.0%) and Isola (4.8%) devices. When Miami Moss fixation or the anterior approach was used, no infection was recorded. In comparison with the non-infected cases, the patients with infectious complications showed the same average values for the curve before and after surgery. At a check up, however, the loss of correction increased to 6 degrees and, after instrumentation removal, to 10 degrees as against 3 degrees in the non-infected patients. Pseudoarthrosis developed in two cases.

The incidence of deep wound infections in patients who had surgery for idiopathic scoliosis was comparable with the data in the relevant literature. A higher number of infections, particularly late ones, in patients treated with the use of modern instrumentation is probably related to a higher volume of these implants. Early infections are a rare feature and their cause is known (allergy, sepsis). Treatment involves surgical intervention; in early infections, instrumentation is retained but is removed in late infections.

Even though our group included a low number of patients with infections, we can conclude that risk factors for the development of infectious complications associated with surgical treatment of idiopathic scoliosis are as follows: allergy, higher age, large volume of metal used for stabilization and the presence of another infectious lesion.