INTRODUCTION: Postoperative inflammatory parameters such as C-reactive protein (CRP), white blood cell count（WBC）and Neutrophil count (NC) are important markers to detect surgical site infection. There are some reports which describe that spine surgery with instrumentation elevates CRP compared with that without instrumentation. However, in all reports, they compared early postoperative inflammatory markers with or without instrumentation in different patients, although it widely changes for each patient. Therefore, we investigated the impact of early postoperative inflammatory reaction with or without instrumentation in the same patients.
METHODS: We reviewed the surgical database of all spine operations performed between June 2006 and November 2022 at our institution. During that period, we performed lumbar decompression surgery with or without instrumentation to treat 2328 consecutive patients with degenerative diseases. Of these, 66 had a history of two-time surgery, one with instrumentation, the other without instrumentation. There are 39 men and 27 women. Mean age at the first surgery was 69 years, and the second surgery was 74. CRP, WBC, and NC were measured before surgery and 1,3,7 and 14 days after surgery. Operating time and estimated blood loss were also recorded. Patients were followed at least 6 months after surgery to determine if any infection had developed.
RESULTS: No patient developed infection after both operations. Surgery without instrumentation (decompression alone) was performed to treat mean 1.6 level (range 1-4). Mean operating time was 65 (33-146) minutes, and blood loss was 62 (10-420) ml. Meanwhile, regarding surgery with instrumentation, all surgical procedures were posterior lumbar interbody fusion (PLIF) with pedicle screw instrumentation. Five patients were treated by 2-level and the other 61 by single-level. Mean operating time was 146 (99-258) minutes, and blood loss was 167 (30-650) ml. CRP: Upon comparing peak CRP concentrations between surgeries with and without instrumentation, it was discerned that the peak was consistently observed on day3 across all patients and both surgical procedures. Following PLIF procedure, there was a significantly elevated CRP concentration in comparison to the laminotomy procedure. Significant interactions were observed between time and PLIF in relation to CRP concentrations, as well as between time and number of operated level (N-level). Contrarily, age and gender did not influence the observed elevations. WBC: Following PLIF procedure, there was a significantly elevated WBC counts in comparison to the laminotomy procedure. Significant interactions were observed between time and PLIF in relation to WBC counts. NC: Following PLIF procedure, there was a significantly elevated NC in comparison to laminotomy procedure. Significant interactions were observed between time and PLIF in relation to NC, as well as between time and N-level. Contrarily, age and gender did not influence the observed elevations in CRP concentrations.
DISCUSSION: This is the first study which investigated early postoperative inflammatory markers after spine surgery with and without instrumentation in the same patients. Early postoperative trends were significantly higher after PLIF than after laminectomy for all three markers, with a significant interaction between time and N-level for CRP and NC. Differences with and without instrumentation were most pronounced for CRP.