This study evaluates the long-term survival of
spinal implants after surgical site infection (SSI) and the risk
factors associated with treatment failure. A Kaplan-Meier survival analysis was carried out on 43 patients
who had undergone a posterior spinal fusion with instrumentation
between January 2006 and December 2008, and who consecutively developed
an acute deep surgical site infection. All were appropriately treated
by surgical debridement with a tailored antibiotic program based
on culture results for a minimum of eight weeks. A ‘terminal event’ or failure of treatment was defined as implant
removal or death related to the SSI. The mean follow-up was 26 months
(1.03 to 50.9). A total of ten patients (23.3%) had a terminal event.
The rate of survival after the first debridement was 90.7% (95%
confidence interval (CI) 82.95 to 98.24) at six months, 85.4% (95%
CI 74.64 to 96.18) at one year, and 73.2% (95% CI 58.70 to 87.78)
at two, three and four years. Four of nine patients required re-instrumentation
after implant removal, and two of the four had a recurrent infection
at the surgical site. There was one recurrence after implant removal
without re-instrumentation. Multivariate analysis revealed a significant risk of treatment
failure in patients who developed sepsis (hazard ratio (HR) 12.5
(95% confidence interval (CI) 2.6 to 59.9); p <
0.001) or who
had >
three fused segments (HR 4.5 (95% CI 1.25 to 24.05); p = 0.03).
Implant survival is seriously compromised even after properly treated
surgical site infection, but progressively decreases over the first
24 months. Cite this article:
The purpose of this study was to determine whether
patients with a burst fracture of the thoracolumbar spine treated
by short segment pedicle screw fixation fared better clinically
and radiologically if the affected segment was fused at the same
time. A total of 50 patients were enrolled in a prospective study
and assigned to one of two groups. After the exclusion of three
patients, there were 23 patients in the fusion group and 24 in the
non-fusion group. Follow-up was at a mean of 23.9 months (18 to
30). Functional outcome was evaluated using the Greenough Low Back
Outcome Score. Neurological function was graded using the American
Spinal Injury Association Impairment Scale. Peri-operative blood transfusion requirements and duration of
surgery were significantly higher in the fusion group (p = 0.029
and p <
0.001, respectively). There were no clinical or radiological
differences in outcome between the groups (all outcomes p >
0.05).
The results of this study suggest that adjunctive fusion is unnecessary
when managing patients with a burst fracture of the thoracolumbar
spine with short segment pedicle screw fixation.