Importance of Hemoglobin A1c Levels for the Detection of Post-Surgical Infection Following Single-Level Lumbar Posterior Fusion in Patients with Diabetes / 대한신경손상학회지

OBJECTIVE: Several studies have reported that patients with diabetes mellitus (DM) are vulnerable to infection. However, the mechanism underlying this remains unclear. We hypothesized that preoperative blood glucose levels in patients with DM may be a risk factor for surgical site infection (SSI). We aimed to investigate the relationship between hemoglobin A1c (HbA1c) level and SSI incidence following single-level spinal fusion surgery. METHODS: Patients with DM who underwent single-level lumbar posterior fusion surgery were retrospectively reviewed. Ninety-two patients were included and classified into the SSI and SSI-free groups. Clinical data with demographic findings were obtained and compared. The HbA1c cut-off value was defined using receiver operating characteristic (ROC) and area under the curve (AUC) analyses, which showed a significantly increased SSI risk. Potential variables were verified using multiple logistic regression analysis. RESULTS: Among the enrolled patients, 24 had SSI and 68 did not within 1 year. The preoperative HbA1c level was higher in patients with SSI (6.8%) than in the non-infected patients (6.0%; p=0.008). ROC analysis showed that if the HbA1c level is higher than 6.9%, the risk of SSI significantly increases (p=0.003; AUC, 0.708; sensitivity, 62.5%; specificity, 70.6%). The preoperative HbA1c level was significantly correlated with SSI incidence, after adjusting for potential variables (p=0.008; odds ratio, 4.500; 95% confidence interval, 1.486–13.624). CONCLUSION: The HbA1c level, indicating glycemic control, in patients with DM may be a risk factor for SSI in single-level lumbar spine posterior fusion.

Effect of Modic Changes in Cervical Degenerative Disease

OBJECTIVE: Modic changes are signal intensity changes in adjacent vertebral bone marrow on magnetic resonance imaging. Few studies have investigated these changes with regard to the cervical spine. In this study, we investigated the associations between cervical degenerative disease and Modic changes. METHODS: We conducted a retrospective collection of radiological data in patients with neck pain at Pusan National University Yangsan Hospital from January 2010 to December 2014. A total of 169 patients were included in this study. Disc herniation grade, disc space height and global cervical lordosis (C2–C7 Cobb angle) were measured and analyzed. If Modic changes were present, we recorded the Modic change type based on the literature, vertebral level, age, sex, and surgical requirement. RESULTS: Sixty-six patients exhibited Modic changes in the cervical spine. Out of these 66 patients, Modic change type II (56 patients, 84.8%) and C5–6 vertebral level (23 patients, 34.8%) were the most predominant categories. Patients with Modic change showed worse outcomes in regard to disc herniation grade, disc space height and global cervical lordosis than patients without (p<0.01). Among 169 patients, 18 patients had undergone anterior cervical discectomy with fusion (ACDF). Patients with Modic changes (10 of 66 patients, 15.1%) had a greater probability of undergoing ACDF than those without (8 of 103 patients, 7.8%; p<0.01). CONCLUSION: Modic changes refer cervical degenerative changes, and incidence of ACDF is higher when the Modic changes are occurred.

Variation of C-Reactive Protein and White Blood Cell Counts in Spinal Operation: Primary Fusion Surgery Versus Revision Fusion Surgery

OBJECTIVE: Serum C-reactive protein (CRP) concentrations and white blood cell (WBC) count are commonly used to identify postoperative wound infections. We investigated whether changes in serum CRP levels and WBC counts actually differed between patients undergoing revision spinal fusion surgery and those undergoing a primary fusion. METHODS: Patients who underwent posterolateral fusion (PLF) surgery at Pusan National University Yangsan Hospital between October 2013 and April 2015 were considered for this study. Sixty-seven patients with primary lumbar PLF (pPLF) and 21 with revision PLF (rPLF) were enrolled. A retrospective assessment of preoperative and postoperative CRP levels and WBC count was undertaken. Also, we gathered peak CRP day, and CRP normalization days. Comorbidity data were also obtained to evaluate any effects on the course of CRP and WBC count postoperatively. RESULTS: CRP levels peaked at 3 days after surgery. The maximum CRP values recorded for each group: 4.17 (standard deviation [SD], 4.18) mg/dL and 4.88 (SD, 3.03) mg/dL for pPLF and rPLF. This difference was not statistically significant (p=0.24). A rapid fall in CRP within 5–9 days was observed for both groups. CONCLUSION: Out of our expectation, changes in CRP levels after spinal fusion surgery follow the same course regardless of whether it is a revision operation or not. Because of this result, both the primary PLF surgery and revision PLF surgery should be monitored using CRP in the similar way and the antibiotic administration should be determined.