Particular Features of Surgical Site Infection in Posterior Lumbar Interbody Fusion.
BACKGROUND
Previous reports have observed differences only in infection rates between posterolateral fusion and posterior lumbar interbody fusion (PLIF). There have been no reports that describe the particular features of surgical site infection (SSI) in PLIF. In this study, we endeavor to identify the distinguishing characteristics and risk factors of SSI in PLIF.


METHODS
Our study undertook a review of a case series of an institute. Patients who had undergone PLIF consecutively in the author's hospital were reviewed. Two proactive procedures were introduced during the study period. One was irrigation of the autolocal bone, and the other was the intradiscal space irrigation with a nozzle. Infection rate and risk factors were analyzed. For subgroup analysis, the elapsed time to a diagnosis (ETD), clinical manifestations, hematologic findings, and causative bacteria were examined in patients with SSI.


RESULTS
In a total of 1,831 cases, there were 30 cases of SSI (1.6%). Long operation time was an independent risk factor (p = 0.008), and local bone irrigation was an independent protective factor (p = 0.001). Two cases of referred SSI were included in the subgroup analysis. There were 6/32 (19%) superficial incisional infections (SII), 6/32 (19%) deep incisional infections (DII), and 20/32 (62%) organ/space infections (O/SI). The difference of incidence among three groups was significant (p = 0.002).The most common bacteria encountered were methicillin-resistant Staphylococcus epidermidis followed by methicillin-resistant S. aureus in incisional infections, and no growth followed by S. epidermidis in O/SI. ETD was 8.5 ± 2.3 days in SII, 8.7 ± 2.3 days in DII and 164.5 ± 131.1 days in O/SI (p = 0.013).


CONCLUSIONS
The rate of SSI in PLIF was 1.6%, with the most common type being O/SI. The causative bacteria of O/SI was of lower virulence than in the incisional infection, and thus diagnosis was delayed due to its latent and insidious feature. Contamination of auto-local bone was presumed attributable to the progression of SSI. Irrigation of auto-local bone helped in the reduction of SSI.
Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea.
Jin Hak
JH
Kim
Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea.
Dong Ki
DK
Ahn
Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea.
Jin Woo
JW
Kim
Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea.
Go We
GW
Kim
D000368:Aged; D005260:Female; D006801:Humans; D015994:Incidence; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D013123:Spinal Fusion / Q000009:adverse effects*; D013530:Surgical Wound Infection / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology
Delayed diagnosis; Organ/space infection; Posterior lumbar interbody fusion; Surgical site infection