Skipping Pedicle Screw Insertion Into Infected Vertebra is a Risk Factor for Revision Surgery for Pyogenic Spondylitis in the Lower Thoracic and Lumbar Spine

Background Surgical intervention for pyogenic spondylitis is indicated when conservative treatment fails and biomechanical instability persists. Whether to insert pedicle screws into all vertebrae, including the most erosive vertebrae, or whether to skip 1 vertebra in pedicle screw insertion remains controversial.

Methods A single-institution retrospective cohort study was conducted in consecutive patients with pyogenic spondylitis in the lower thoracic and lumbar spine (T9–S1) between January 2008 and December 2016. The patients were treated with interbody fusion plus posterior stabilization using pedicle screws and were divided into 2 groups as follows: (1) patients in whom 1 vertebra, usually the most erosive, was skipped in pedicle screw insertion (Group Skipping) and (2) pedicle screw insertion into all vertebrae (Group All). Patients' operation data were evaluated, and clinical outcomes were compared between the 2 groups. There were no significant differences between the 2 groups in terms of age, sex, past histories, blood loss, operation time, the presence of abscesses, or operative approach.

Results The length of fixation was greater by 1 vertebral level in the Group Skipping than in the Group All, and the rate of revision surgery for pseudarthrosis was higher in the Group Skipping than in the Group All (P = .02). There was no statistically significant difference between the 2 groups in terms of the mean segmental lordotic angle or Barthel Index.

Conclusions Skipping pedicle screw insertion for pyogenic spondylitis in posterior fixation led to an increased number of fixed vertebrae and may be a risk factor for revision surgery for pseudarthrosis.

Level of Evidence 4.

Clinical Relevance The insertion of short pedicle screws at the infected vertebra can prevent early treatment failure and increase the biomechanical stability of construct.