Early-phase enhanced inflammatory reaction after spinal instrumentation surgery

Logistic regression model predicts early surgical site infection after spinal fusion: a retrospective cohort study

OBJECTIVE

This study aimed to develop a diagnostic model for predicting early surgical site infection (SSI) based on postoperative inflammatory markers after spinal fusion surgery.

METHODS

In this retrospective study, we analysed the trends of inflammatory markers between SSI and non-SSI groups. The data were randomly divided into training cohort and validation cohort (ratio 7:3). The variables for SSI were analysed using stepwise logistic regression to develop the prediction model. To evaluate the model, we analysed its sensitivity, specificity, positive predictive value, negative predictive value, as well as the area under the curve in the validation cohort. Calibration plots and decision curve analysis were employed to assess the calibration and clinical usefulness of the model.

FINDINGS

We observed significant changes in inflammatory markers on the seventh day after surgery. The prediction model included four variables on the seventh day after surgery: body temperature, C-reactive protein, erythrocyte sedimentation rate and neutrophil counts. After binary processing of these data, the simplified model achieved an area under the curve of 0.86 (95% confidence interval (CI): 0.81-0.92) in the training cohort and 0.9 (95% CI: 0.82-0.98) in the validation cohort. Calibration plots and decision curve analysis demonstrated that the proposed model was effective for the diagnosis of SSI.

CONCLUSION

We developed and validated a prediction model for diagnosing early infection after spinal fusion.

Risk Factors for Postoperative Surgical Site Infection in Patients Undergoing Spinal Tumor Surgery

STUDY DESIGN

A retrospective comparative case-control study.

OBJECTIVE

The aim of this study was to determine the risk factors for postoperative surgical site infection (SSI) in patients with spinal tumors requiring reoperation during the perioperative period.

SUMMARY OF BACKGROUND DATA

SSI is a common postoperative complication of spinal surgery. The occurrence of SSI not only increases the mortality rate but prolongs the patient's hospital stay and increases the medical cost.

METHODS

Included in this study were 202 patients with spinal tumors who received surgical treatment between January 2008 and December 2018, of whom 101 patients who developed SSI and underwent secondary surgery were used as the SSI group, and the other 101 patients with no SSI who were matched with the SSI group by age (±10), pathologic diagnosis (malignant/no-malignant), tumor site (C/T/L/S), surgical approach (anterior/posterior/combined), and surgical team were used as the control group. The clinical data of the 202 patients in both groups were analyzed by logistic regression modeling to identify SSI-associated risk factors.

RESULTS

Multivariate logistic regression analysis showed that the revision status ( B =1.430, P =0.028), the number of spinal levels fused ≥4 ( B =0.963, P =0.006), and the use of bone cement ( B =0.739, P =0.046) were significantly associated with the increased risk of developing postoperative SSI.

CONCLUSIONS

This study identified the revision status, the number of spinal levels fused ≥4, and the use of bone cement as independent risk factors for SSI in patients with spinal tumors who underwent reoperation during the perioperative period.

Post-operative C-reactive protein and white blood cells changes pattern following spinal deformity surgery and its clinical correlation

OBJECTIVE

Following the changing pattern of post-operative CRP and WBC counts and compare them to the patient's clinical condition to find which one is better for early detection of early infection.

METHODS

A total of 50 patients who underwent spinal deformity correction surgery without clinical signs of infection such as fever, wound redness, or discharge were enrolled in this prospective study. The C-reactive protein (CRP) and white blood cell (WBC) counts were measured the 2nd and 7th post-operative days. We try to detect the type of correlation between both CRP and WBCs level and clinical condition of patient regarding wound local condition.

RESULTS

All cases showed high CRP by the 2nd day post-operative which decreased significantly but not reaching normal levels even by the 7th day. All cases showed elevated WBCs count by the 2nd day which decreased to normal levels by the 3rd day in 86% of patients, and by the 7th day, 94% of cases showed normal levels. In addition, WBCs in the 2nd day post-operative significantly positive correlated with fusion level and operative time. There was no significant correlation between WBCs and blood transfusion or age. No significant correlation between CRP and number of fusion levels, blood transfusion nor operative time.

CONCLUSION

WBCs count returned earlier to normal levels than CRP in our cases, so monitoring early changes in the 1st week in WBCs count pattern is more indicative of an ongoing infectious process.

A prospective study to identify preoperative serum parameters for spinal implant infection detected by sonication fluid culture

PURPOSE

Low-virulent microorganisms identified on pedicle screws by sonication fluid culture (SFC) are an important cause of implant loosening. While sonication of explanted material improves the detection rate, the risk of contamination exists and no standardized diagnostic criteria for chronic low-grade spinal implant-related infection (CLGSII) are stablished. Besides, the role of serum C-reactive protein (CRP) and procalcitonin (PCT) in CLGSII has not been adequately investigated.

METHODS

Blood samples were collected prior to implant removal. To increase sensitivity, the explanted screws were sonicated and processed separately. Patients exhibiting at least one positive SFC were classified in the infection group (loose criteria). To increase specificity, the strict criteria only considered multiple positive SFC (≥ 3 implants and/or ≥ 50% of explanted devices) as meaningful for CLGSII. Factors which might promote implant infection were also recorded.

RESULTS

Thirty-six patients and 200 screws were included. Among them, 18 (50%) patients had any positive SFCs (loose criteria), whereas 11 (31%) patients fulfilled the strict criteria for CLGSII. Higher serum protein level was the most accurate marker for the preoperative detection of CLGSSI, exhibiting an area under the curve of 0.702 (loose criteria) and 0.819 (strict criteria) for the diagnosis of CLGSII. CRP only exhibited a modest accuracy, whereas PCT was not a reliable biomarker. Patient history (spinal trauma, ICU hospitalization and/or previous wound-related complications) increased the likelihood of CLGSII.

CONCLUSION

Markers of systemic inflammation (serum protein level) and patient history should be employed to stratify preoperative risk of CLGSII and decide the best treatment strategy.

Delayed Infection 34 Months After IntraSPINE® Dynamic Internal Insertion

Introduction

Postoperative surgical site infection remains one of the major complications after spinal surgery. IntraSPINE^® (intraspine) is a dynamic intralaminar device introduced by Cousin Biotech and is indicated for the surgical treatment of lumbar spine disorders. There are no reports on delayed surgical site infection (SSI) after lumbar surgery using this device.

Case Presentation

A 29-year-old male patient was admitted to our department with complaints of moderate pain and chronic subcutaneous abscess with purulent flow from his old surgical scar. Thirty-four months ago, he underwent a traditional open bilateral L4 laminotomy without discectomy and intraspine insertion for the treatment of L4-5 central lumbar spinal stenosis at another hospital. The patient was discharged 4 days after surgery without radiating pain, and the surgical wound was well healed. He gradually returned to his normal activity and work. However, he experienced moderate pain, redness and swelling of his old surgical scar approximately one month before coming to our hospital, but he did not receive any treatment. One month later, he had a mass with purulent discharge at the surgical scar site, and he visited our hospital on December 29th, 2020. Based on the physical examination and MRI findings, delayed -SSI was diagnosed. The patient underwent removal of the intraspine device, debridement and wound closure with closed drainage. The wound healed satisfactorily, and the patient had no complaints more than 2 years later.

Conclusion

A delayed surgical site infection following intraspine insertion may have occurred.

Temporal Evolution of White Blood Cell Count and Differential: Reliable and Early Detection Markers for Surgical Site Infection Following Spinal Posterior Decompression Surgery

Introduction

For early detection of surgical site infection (SSI) following spinal decompression surgery, we compared temporal changes in the values of laboratory markers that are not affected by operative parameters.

Methods

The study included 302 patients, which were divided into an SSI group (patients who developed deep SSI) and a non-SSI group for analysis. We reviewed data on C-reactive protein level, total white blood cell (WBC) count, and WBC differential percentage and count before spinal decompression, on postoperative day 1, and on postoperative day 4. We identified laboratory markers that are not affected by operative parameters (operating time, intraoperative blood loss, and number of operative segments). Laboratory markers with a significant difference observed between the peak or nadir value and the value in the subsequent survey day were considered as an indicator of SSI. We examined the utility of each indicator by calculating sensitivity and specificity. Furthermore, we investigated the utility of the combination of all five indicators (wherein the recognition of one marker was considered positive).

Results

Temporal changes in five laboratory markers were considered indicators of SSI. The changes from postoperative day 1 to postoperative day 4 were as follows: (1) increased WBC count (42% sensitivity, 88% specificity), (2) increased neutrophil percentage (25% sensitivity, 96% specificity), (3) increased neutrophil count (25% sensitivity, 94% specificity), (4) decreased lymphocyte percentage (25% sensitivity, 95% specificity), and (5) decreased lymphocyte count (25% sensitivity, 85% specificity). The combination of these five markers showed a 50% sensitivity, 81% specificity, and 0.65 AUC.

Conclusions

Five markers were found to be reliable indicators of SSI following spinal decompression surgery because they were not affected by operative parameters. The combination of all five indicators had moderate sensitivity and high specificity. Therefore, this may be reliable and useful for the early detection of SSI.

A novel approach for identifying serological markers indicative of surgical-site infection following spine surgery: Postoperative lymphopenia is a risk factor

BACKGROUND

Postoperative lymphopenia (PL) after spine surgery is reported to be an indicator of surgical-site infection (SSI). PL without SSI is often encountered, resulting in a treatment dilemma. We focused on PL, so as to improve the accuracy of detecting SSI.

METHODS

In total, 329 patients underwent spine surgery, including nine patients presenting with SSI. The complete blood cell counts, differential counts, and C-reactive protein (CRP) level were measured pre-surgery and on postoperative days 2, 7, and 14. The relationships between PL and SSI were evaluated, and PL and non-PL conditions were compared among all cases. We then divided the patients into two groups: PL and non-PL, and determined the useful serological markers using receiver operating characteristic curves.

RESULTS

Sixty-one patients presented with PL, including four with SSI. However, PL was not directly suggested as a biomarker of SSI (p = 0.067). We revealed PL as a risk factor for SSI (p = 0.004, Odds ratio: 7.54). Among all cases, the lymphocyte count and CRP level differed significantly between the PL and non-PL groups at all perioperative time-points. The white blood cell count, neutrophil count, and CRP levels on postoperative day 7 significantly differed between the SSI and non-SSI cases in the PL group. The area under the curve (AUC) for CRP was greater than that of the other parameters. The neutrophil count was only effective as a marker in the non-PL group. The combination of two cutoff values (CRP: 3.7 mg/dL (PL group) and neutrophil count: 6172/μL (non-PL group)) presented high specificity (87.2%) and sensitivity (88.9%), while only one cutoff value (CRP: 2.9 mg/dL) had a specificity of 77.4% and sensitivity of 77.8%.

CONCLUSIONS

Approximately one-fifth of patients developed PL post-surgery, which was a risk factor for SSI, with constant high inflammation. Grouping based on PL and establishing diagnostic cutoff values are more appropriate than establishing only one cutoff value for overall cases.

Establishment of a suitable combination of serological markers to diagnose surgical site infection following spine surgery: A novel surgical site infection scoring system

BACKGROUND

The accuracy rates of several effective serological markers of surgical site infection following spine surgery are unclear. We aimed to verify the accuracy of each significant marker and identify the most suitable and effective combination of these markers for the diagnosis of surgical site infection following spine surgery.

METHODS

This retrospective study enrolled 329 patients who underwent spine surgery for causes other than infectious spondylitis, including 9 patients with surgical site infection. Complete blood cell count, differential counts, and C-reactive protein levels were measured preoperatively and postoperatively (days 2 and 7). Serological data were compared among non-surgical site infection and surgical site infection cases. Cutoff values for items presenting significant differences were determined using receiver operating characteristic curves. Ratios in each serological factor at each time-point were compared. Combinations of these factors on postoperative day 7 and ratio items were investigated to determine the most suitable combination comprising the least number of items.

RESULTS

Significant differences were noted among four factors on postoperative day 7, except for the lymphocyte count. For the ratio items, significant differences were observed among 6 items. The combination of these ten markers was examined; each factor was assigned 1 point. The most suitable combination comprising 4 items, including neutrophil count, neutrophil-to-lymphocyte ratio, lymphocyte count ratio, and C-reactive protein ratio, presented an AUC of 0.95, with a cutoff value, sensitivity, and specificity of 3 points, 0.89, and 0.92, respectively.

CONCLUSION

The combination of four markers is the most suitable criterion for the surgical site infection scoring system following spine surgery, where scores of ≥3 points strongly indicate surgical site infection. This criterion may be a strong tool for detecting surgical site infection.

Protein Supplement and Enhanced Recovery After Posterior Spine Fusion Surgery: A Randomized, Double-blind, Placebo-controlled Trial

STUDY DESIGN

This was a randomized, double-blind clinical trial study.

OBJECTIVE

The objective of this study was to evaluate the effect of protein supplementation on vertebral fusion and enhanced recovery after posterior spine fusion (PSF) surgery.

SUMMARY OF BACKGROUND DATA

Nonfusion is one of the most common complications of lumbar spine surgery. It has been shown that protein plays an important role in bone repair; however, its correlation to vertebral fusion following PSF surgery is unknown.

PATIENTS AND METHODS

In this randomized, double-blind clinical trial study, the intervention group received a diet with 1.2 g of protein plus high-protein supplement (36 g whey protein), and the control group received a similar diet, except for starch as a placebo from 48 hours before to 1 month after surgery.

RESULTS

The intervention group showed a significantly higher rate of vertebral fusion compared with the control group (P=0.019). Surgical site infection and pain were significantly lower in the intervention group. A significant difference was found in the wound healing rate in favor of the intervention group. The rates of decrease in serum high-sensitivity C-reactive protein levels and increase in serum levels of insulin-like growth factor 1, albumin, total protein, and alkaline phosphatase were greater in the intervention group than in the control group (P<0.001).

CONCLUSIONS

Increased protein intake improves vertebral fusion and enhances recovery in patients undergoing PSF. This was the first study to investigate the effect of protein on fusion and healing factors; as a result, further clinical trials are needed to confirm the current results.

Inflammatory biomarkers to predict postoperative infectious complications after cytoreductive surgery and HIPEC for peritoneal carcinomatosis

BACKGROUND

Early detection of postoperative infectious complications (IC) is crucial after Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). The aim of this study was to evaluate the predictive role of early postoperative inflammatory biomarkers level for the detection of postoperative IC.

METHODS

a retrospective study was performed including 199 patients treated with complete CRS/HIPEC for PC from various primary origins from September 2012 to January 2021. Patients were monitored by a routine measurement of inflammatory biomarkers (CRP, leukocytes, neutrophils, lymphocytes, neutrophile-to-lymphocyte ratio and platelets-to-lymphocyte ratio). Inflammatory biomarkers were compared between patients with vs without IC.

RESULTS

IC occurred for 68 patients (34.2%). CRP values were significantly higher in patients with IC on POD 3, 5 and 7 (CRP = 166 mg/L [128-244], 155 mg/L [102-222] and 207 mg/L [135-259], respectively). The CRP on POD7, with a cut-off value of 100 mg/L, was an excellent predictor of postoperative IC (AUC = 90.1%). The CRP on POD 5, with a cut-off value of 90 mg/L, was a good predictor of postoperative IC (AUC = 83.2%). NLR values were significantly higher in patients with IC on POD 3, 5 and 7. NLR on POD 5 and 7 higher than 9.7 and 6.3, respectively, were fair predictors (AUC = 70.8 and 79.6, respectively).

CONCLUSION

CRP levels between POD3 and 7 are the best predictors of postoperative IC after CRS/HIPEC. The presence of postoperative IC should be suspected in patients with CRP higher than 140 mg/L, 90 mg/L or 100 mg/L on PODs 3, 5 or 7.

Changes in Invasiveness and Latent Infection Rate Associated with Switching the Approach in Total Hip Replacement

Purpose:

Muscle-sparing approaches for total hip replacement (THR) involve learning curves. This study aimed to clarify changes in invasiveness and infection rate with changes in approach.

Methods:

One surgeon changed the approach of THR from Dall’s approach (Dall) to anterolateral modified Watson-Jones approach (OCM). Another changed from Dall to a direct anterior approach (DAA). Another 3 surgeons changed from posterolateral approach (PL) to OCM. Subjects were 150 cases, comprising the last 25 cases with conventional approaches and the first 25 cases with new approaches (Dall to OCM: 25 + 25; Dall to DAA: 25 + 25; PL to OCM: 25 + 25 cases). Differences in operative time, bleeding volume, hospital stay, haemoglobin (Hb), white blood cell count, lymphocyte count, creatine kinase (CK) and C-reactive protein (CRP) were investigated.

Results:

In the change from Dall to OCM, only hospital stay decreased. In the change from Dall to DAA, hospital stay and CRP decreased, but bleeding volume increased. In the change from PL to OCM, operative time, CRP and CK decreased, but Hb also decreased. Cases with lymphocyte count <1000/μL or lymphocytes comprising <10% of total white blood cells at around day 4 after surgery were defined as latent infection cases. In these cases, operative time was longer, Hb was lower and CK was higher.

Conclusion:

Introducing muscle-sparing approaches improved many markers of invasiveness, but some items deteriorated. In the early stages of introducing a new approach, choosing cases without obesity and without high muscle volume may reduce the risk of infection.

Serum C-reactive protein and WBC count in conservatively and operatively managed bacterial spondylodiscitis

PURPOSE

C-reactive protein (CRP) and white blood cell (WBC) count are routine blood chemistry parameters in monitoring infection. Little is known about the natural history of their serum levels in conservative and operative spondylodiscitis treatment.

METHODS

Pre- and postoperative serum levels of CRP and WBC count in 145 patients with spondylodiscitis were retrospectively assessed. One hundred and four patients were treated by debridement, spondylodesis, and an antibiotic regime, 41 only with a brace and antibiotics. The results of the surgical group were compared to 156 patients fused for degenerative disc disease (DDD).

RESULTS

Surgery had a significant effect on peak postoperative CRP levels. In surgically managed patients, CRP peaked at 2-3 days after surgery (spondylodiscitis: pre-OP: 90 mg/dl vs. post-OP days 2-3: 146 mg/dl; DDD: 9 mg/dl vs. 141 mg/dl; p < 0.001), followed by a sharp decline. Although values were higher for spondylodiscitis patients, dynamics of CRP values were similar in both groups. Nonoperative treatment showed a slower decline. Surgically managed spondylodiscitis showed a higher success rate in identifying bacteria. Specific antibiotic treatment led to a more predictable decline of CRP values. WBC did not show an interpretable profile.

CONCLUSION

CRP is a predictable serum parameter in patients with spondylodiscitis. WBC count is unspecific. Initial CRP increase after surgery is of little value in monitoring infection. A preoperative CRP value, and control once during the first 3 days after surgery is sufficient. Closer monitoring should then be continued. Should a decline not be observed, therapy needs to be scrutinized, antibiotic treatment reassessed, and concomitant infection contemplated.

Interleukin-6 as inflammatory marker of surgical site infection following spinal surgery

BACKGROUND

In order to elucidate whether serum inflammatory markers identify patients with local surgical site infection(SSI) as underlying disease for recurrent or new symptomatology following spine surgery, we evaluated the diagnostic potential of interleukin-6(IL-6) as a marker of SSI. The diagnostic significance of IL-6 was compared to the standard serum inflammatory markers C-reactive protein(CRP) and white blood cell count (WBCC).

METHOD

Ninety-eight consecutive patients with readmission due to recurrent or new symptomology after spinal surgery of degenerative spine disorders entered the study. Baseline patients' characteristics and the abovementioned inflammatory markers were collected, and arithmetical means with standard deviation, area under the curve (AUC), thresholds, sensitivity, specificity, positive(+)likelihood ratio (LR), and negative(-)LR with corresponding 95% confidence interval(95%CI) were calculated and correlated with presence or absence of SSI.

RESULTS

Nine patients suffered from a SSI, whereas the remaining 89 patients had a recurrent/adjacent-segment degenerative disorder without evidence of infection. The most significant parameter for diagnosing a SSI was serum IL-6 (cut-off value > 15.3 pg/ml, AUC = 0.954, SE = 85.7%, SP = 97.3%), followed by CRP (cut-off value = 0.8 mg/dl, AUC = 0.916, SE = 88.9%, SP = 84.5%) CONCLUSIONS: In the case of recurrent or new symptomatology following spinal surgery, serum IL-6 has the highest diagnostic potential for diagnosing spinal SSI.

Usefulness of inflammatory markers and clinical manifestation for an earlier method to diagnosis surgical site infection after spinal surgery

PURPOSE

To put forward a method for earlier diagnosis of surgical site infection (SSI) after spinal surgery and identify the best cut-offs of the selective signs.

METHODS

Ninety cases were prospectively collected in consecutive patients who underwent spinal surgery. The patients were divided into the SSI group and the normal group. White blood cell (WBC) count, lymphocyte count, serum amyloid A (SAA), procalcitonin (PCT) and C-reactive protein (CRP) were collected pre-operatively and at three andsix days post-operatively. Erythrocyte sedimentation rates (ESR) were acquired pre-operatively and at six days post-operatively. Body temperature (BT) was measured every day during hospitalisation. The conditions of the surgical sites were recorded at three and six days post-operatively. Differences of BT, the conditions of the wound and the values of the inflammatory markers between the two groups were studied. Finally, we used the receiver operating characteristic curve (ROC curve) to determine the best cut-offs of the selected signs.

RESULTS

Of the 90 patients, SSI occurred in seven and five of them reached a definite diagnosis of SSI as their bacterial cultures were positive. Significant differences were found in CRP levels at three and six days post-operatively with a cut-off of > 59.4 mg/L and > 34.9 mg/L, respectively; ESR level at six days post-operatively with a cut-off of > 51.5 mm/h; PCT at three days post-operatively with a cut-off of > 0.11 ng/mL; and BT at three days post-operatively with a cut-off of > 37 °C. Also, examination of the wound is also an important sign of SSI.

CONCLUSION

CRP, ESR and PCT are considered useful markers for earlier diagnosis of SSI. Combining the above markers with BT and the wound condition yields more accurate results.

Increased interleukin-6 and C-reactive protein levels after instrumented lumbar spine fusion in older patients

PURPOSE

Interleukin 6 (IL-6) and the acute phase C-reactive protein (CRP) blood concentrations after lumbar spine fusion may be affected by age. The purpose of this prospective observational study was to assess postoperative serum levels of pro-inflammatory IL-6 and CRP after instrumented lumbar spine fusion surgery. We hypothesized that older patients would have increased levels of IL-6 and CRP after surgery.

METHODS

IL-6 and high-sensitive CRP biochemical marker levels were measured before instrumented spinal fusion, and postoperatively at 1 and 3 days, 6 weeks, and 3 months. The 49 patients in this sample were divided into two groups: age ≤ 60 years ( n = 23) and age > 60 years ( n = 26).

RESULTS

Acute changes in IL-6 high-sensitivity and CRP from preoperative levels to postoperative day (POD) 1 increased with age. Mean (95% CI) difference between the age-groups in changes of IL-6 at PODs 1 and 3 was 45 pg/ml (10-83, p = 0.014) and 20 pg/ml (5-36, p = 0.021), respectively. Mean (95% CI) difference between groups in changes of CRP at PODs 1 and 3 was 9.6 mg/l (-3.5 to 22.7, p = 0.47) and 24.8 mg/l (-17 to 67, p = 0.33), respectively. Both groups had decreased IL-6 and CRP levels at 6 weeks after surgery compared to the preoperative level.

CONCLUSIONS

Elevation of IL-6 and CRP is stronger in patients over 60 years old after instrumented lumbar spinal fusion. The CRP and IL-6 are sensitive markers for acute postoperative inflammation. Even high acute CRP values do not necessarily indicate postoperative infection.

Retrospective study to evaluate the clinical significance of a second rise in C-reactive protein level following instrumented spinal fusion surgery

BACKGROUND

This study aimed to identify the incidence and causes of a second rise in C-reactive protein (CRP) levels following spinal instrumentation surgery and to help determine how an abnormal CRP response should be interpreted and managed during postoperative care.

METHODS

The medical records of 948 patients who underwent instrumented spine fusion surgery and met the inclusion criteria were retrospectively reviewed to assess the frequency and causes of a second rise (SR) of CRP. A SR of CRP was defined when the CRP level after postoperative day 7 increased by more than 0.5 mg/dl from that at the previous time-point. The diagnostic cut-off value of CRP elevation for detection of surgical site infection (SSI) was determined. Cut-off values were analyzed using receiver operating characteristic (ROC) curves. Bayes' theorem was used to determine blood test posterior probabilities for SSI-positive cases using cutoff values of re-evaluated CRP levels.

RESULTS

SR of CRP occurred in 107 of the 948 patients. Of the patients with SR of CRP, 38 (35%) patients had developed SSI, 33 (31%) patients had causes other than SSI, and the remaining 36 patients had unidentified causes. Among the patients with SR, excluding those with causes other than SSI, the best diagnostic cut-off value of SR for detection of SSI was 3.04 mg/dl (area under the curve was 0.74). The posterior test probability was 84.4%.

CONCLUSIONS

For patients with SR of CRP, who had no causes other than SSI, an SR value of 3.04 mg/dl correlated with a high probability of developing SSI.

Lymphocyte Count at 4 Days Postoperatively: A Reliable Screening Marker for Surgical Site Infection After Posterior Lumbar Decompression Surgery

STUDY DESIGN

Case-control study.

OBJECTIVE

To identify laboratory markers for surgical site infection (SSI) in posterior lumbar decompression surgery, which are not affected by operative factors, and to determine the diagnostic cutoffs of these markers.

SUMMARY OF BACKGROUND DATA

Numerous laboratory markers are used for the early detection of SSI; however, these markers may be affected by operative factors.

METHODS

The study included 182 participants. They were divided into an SSI group (patients who developed deep SSI; n = 8) and a no-SSI group (n = 174). We reviewed data on the C-reactive protein level and total white blood cell count and differential count before posterior lumbar decompression surgery and 1 and 4 days postoperatively. We determined which markers differed significantly between the groups and identified the markers that were not affected by operative factors (operative time, intraoperative blood loss, and number of operative segments) in the no-SSI group. We then determined the diagnostic cutoffs of these unaffected markers using receiver operating characteristic curves.

RESULTS

We identified the lymphocyte percentage at 4 days postoperatively (cutoff, <19.4%; sensitivity, 80.0%; specificity, 62.5%; area under the curve, 0.78) and lymphocyte count at 4 days postoperatively (cutoff, <1010/μL; sensitivity, 93.7%; specificity, 62.5%; area under the curve, 0.78) as reliable markers.

CONCLUSION

Lymphocyte percentage and count at 4 days postoperatively are reliable markers for SSI after posterior lumbar decompression surgery. Lymphocyte count at 4 days postoperatively can be considered as a superior marker for screening because it has a high sensitivity and can be measured early.

LEVEL OF EVIDENCE

4.

Postoperative Changes in Presepsin Level and Values Predictive of Surgical Site Infection After Spinal Surgery: A Single-Center, Prospective Observational Study

STUDY DESIGN

Single-institutional, prospective observational study.

OBJECTIVE

To elucidate the perioperative kinetics of presepsin (PSEP) in patients undergoing spinal surgery, and to evaluate the possibility of PSEP in the early diagnosis of surgical site infection (SSI).

SUMMARY OF BACKGROUND DATA

Early diagnosis of SSI after spinal surgery is important. Although several biomarkers have been used as early indicators of SSI, the specificity of these markers in SSI diagnosis was not high. PSEP was found as a novel diagnostic marker for bacterial sepsis in 2004. However, its kinetics after spinal surgery and its usefulness in early diagnosis of SSI have never been evaluated.

METHODS

A total of 118 patients who underwent elective spinal surgery were enrolled. PSEP was measured before, immediately after, 1 day after, and 1 week after surgery. In patients without postoperative infection, perioperative kinetics of PSEP were analyzed. PSEP levels in patients with postoperative infection were also recorded separately, and their utility in SSI diagnosis was evaluated.

RESULTS

In the 115 patients without postoperative infection, the median PSEP value was 126, 171, 194, and 147 pg/mL before, immediately after, 1 day after, and 1 week after surgery, respectively. Compared with the preoperative value, PSEP was significantly higher immediately after surgery and the next day, and return to the preoperative level 1 week after surgery. The estimated reference value for 95 percentile in patients without postoperative infection was 297 pg/mL 1 week after surgery. In three patients with postoperative infection, higher levels (>300 pg/mL) were observed 1 week after surgery.

CONCLUSION

In patients after spinal surgery without infectious complications, blood levels of PSEP may immediately increase and return to preoperative levels 1 week after surgery. The PSEP value of 300 pg/mL 1 week after surgery might be used as a novel indicator for suspected SSI.

LEVEL OF EVIDENCE

4.

Comparison of neutrophil and lymphocyte at 1 and 4 days postoperatively: reliable and early detection markers for surgical site infection following instrumented spinal fusion

Introduction

To identify the temporal comparison of biochemical markers for early detection of surgical site infection (SSI) following instrumented spinal fusion that are not affected by operative factors.

Methods

We reviewed data on C-reactive protein level and total white blood cell count and differential count before instrumented spinal fusion and at 1, 4, and 7 days postoperatively. The 141 patients in our sample were divided into an SSI group (patients who developed deep SSI) and a non-SSI group. We investigated the peak or nadir value day and identified those not affected by operative circumstances (operating time, intraoperative blood loss, and number of fusion segments) in the non-SSI group. If there was a significant difference between the peak or nadir value day and the next survey day, we considered the temporal comparison between these unaffected markers as an indicator of SSI and examined the usefulness of these indicators by calculating sensitivity and specificity. Furthermore, we investigated the usefulness of the combination of these markers (if even each one marker was recognized, we considered it positive).

Results

Four biochemical markers of SSI were selected: neutrophil percentage at postoperative day 4 more than day 1 (sensitivity 36%, specificity 95%), neutrophil count at postoperative day 4 more than day 1 (sensitivity 46%, specificity 93%), lymphocyte percentage at postoperative day 4 less than day 1 (sensitivity 36%, specificity 90%), and lymphocyte count at postoperative day 4 less than day 1 (sensitivity 36%, specificity 90%). The combination of these markers showed sensitivity 100%, specificity 80%, respectively.

Conclusions

Four markers are reliable indicators for early detection of SSI following spinal instrumented fusion because they are not affected by operative factor. The combination of each indicator had both high sensitivity and specificity. Therefore, it is reliable and much useful for early detection of SSI.

White Blood Cell Count and C-Reactive Protein Variations After Posterior Surgery With Intraoperative Radiotherapy for Spinal Metastasis

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To evaluate the feasibility of blood test parameters [white blood cell (WBC) count and C-reactive protein (CRP)] for predicting and diagnosing postoperative infection after posterior surgery with intraoperative radiotherapy (IORT) for spinal metastasis.

SUMMARY OF BACKGROUND DATA

Posterior surgery with IORT is effective for treating spinal metastasis, as we previously reported. However, the procedure requires that the patient be transferred from the operating room to the irradiation room. In addition, the patient's general status is often poor, and the risk of postoperative infection is high.

MATERIALS AND METHODS

A total of 279 patients who underwent IORT for the treatment of spinal metastasis between August 2004 and June 2013 were included in this study. The WBC count (/10 μL) and CRP level (mg/dL) were recorded in all patients preoperatively and on alternative days for up to 7 days after surgery. We assessed the development of surgical-site infection (SSI) for up to 1 month after surgery.

RESULTS

SSI occurred in 41 patients (14.7%). The preoperative WBC count and CRP level did not differ between the infected and noninfected patients. The WBC counts on postoperative day (POD) 1 and POD 7 and the CRP levels on POD 7 were significantly higher in the infected patients (8.8 vs. 10.0, P=0.04; 6.1 vs. 8.8, P=0.002; 3.89 vs. 9.50, P<0.001). A receiver-operating characteristic curve analysis of the WBC count and CRP level for detecting SSI showed cutoff values of 9.6 (WBC count, POD 1), 6.5 (WBC count, POD 7), and 5.0 (CRP level, POD 7).

CONCLUSIONS

A high WBC count and CRP level on POD 7 may be used to predict or detect SSI. In particular, a CRP level of 5.0 mg/dL on POD 7 strongly suggests the future development of SSI (sensitivity: 78%, specificity: 74%).

Postoperative Kinetics of C-Reactive Protein and Erythrocyte Sediment Rate in One-, Two-, and Multilevel Posterior Spinal Decompressions and Instrumentations

STUDY DESIGN

Prospective study.

OBJECTIVE

To characterize the normal pattern of kinetics of postoperative C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) after decompression, spinal instrumentation, and posterolateral fusion in 1, 2, and more than 2 levels.

METHODS

Blood specimens were obtained from patients who underwent posterior decompression, instrumentation with pedicular screws, and posterolateral fusion from June 2009 to January 2011. CRP and ESR levels were measured on the day before surgery and on postoperative days 1, 3, 7, 11, 14, 28, and 42.

RESULTS

Mean CRP levels peaked on the third day postoperatively in all groups. By day 7 postoperatively, it had dropped rapidly. At the 14th and 28th postoperative days, decreases to normal CRP levels were found in 16% and 80% of all patients, respectively. The pattern of decline in CRP was similar among groups. Values of ESR increased and peaked between the third and seventh postoperative days. ESR values gradually decreased. At the 42 day postoperatively, ESR level still remain above normal values in all groups.

CONCLUSIONS

We compared conventional operation groups of 1-, 2-, and more than 2-level posterior instrumentation and found no statistically significant differences in the peak of CRP level, the ESR value, and the pattern of decline. CRP levels of 80% of the patients returned to normal within 4 weeks.

Deep spinal infection in instrumented spinal surgery: diagnostic factors and therapy

AIM

Postoperative surgical site infections (SSI) are complication of spinal surgery. These complications may lead to a poor outcome with neurological deficits, spinal deformity and chronic pain. The purpose of this study is to explore the statistical value of diagnostic parameters and the proper therapy.

METHOD

We retrospectively reviewed 550 patients who underwent spinal instrumentation at our department from January 2011 to December 2015. The SSI was present in 16 patients out of 550 operated. Diagnostic criteria of SSI were the positivity of the surgical wound swab or blood culture, the clinical findings, positivity of laboratory tests and radiological elements. All patients had peri-operative antibiotic prophylaxis. Diagnostic laboratory findings were compared with a homogeneous control group of 16 patients and analyzed by univariate statistical analysis with Chi-square test for the discrete variables. P<0,05 was considered statistically significant.

RESULTS

Matching the SSI patients with a group of control, fever was not statistically significant for diagnosis as number of leukocytes, neutrophils and lymphocytes. On the contrary values of ESR and CRP were statistically significant with p <0, 01. The hardware was removed only in 3 patients (18%) out of 16 SSI patients.

CONCLUSION

In this study the statistically significant parameters to diagnose SSI are ESR and CRP values. The leucocytes count, number of lymphocytes and presence of fever integrates the data of ESR and CRP with no statistical significance. Most patients with SSI reach clinical healing with favorable outcome by means of target antibiotic therapy without hardware removal.

Surgical Site Infections Caused by Methicillin-resistant Staphylococcus epidermidis After Spinal Instrumentation Surgery

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To determine relevant demographics, clinical presentations, and outcomes of surgical site infections (SSIs) after spinal instrumentation (SI) surgery caused by methicillin-resistant Staphylococcus epidermidis (MRSE).

SUMMARY OF BACKGROUND DATA

This is the first study looking specifically at MRSE-related SSIs after SI surgery.

METHODS

We performed a retrospective review of patients with MRSE-related SSIs from 665 consecutive cases of SI surgery performed between 2007 and 2014 at our institution.

RESULTS

During the study period, SSIs occurred in 21 patients. MRSE was isolated from cultures obtained from surgical wounds in nine of the 21 patients (43%). There were four males and five females with a mean age of 63.9 ± 15.1 years. Six patients presented with inflammatory signs, such as wound drainage, pyrexia, erythema, and elevated C-reactive protein. Three patients did not have signs of infection, but had early implant failure, and were diagnosed by positive cultures collected at the time of revision surgery. The mean time from index surgery to the diagnosis of infection was 23.6 days (range, 7-88 days). In one patient, the implant was removed before antibiotic treatment was administered because of implant failure. Eight patients were managed with antibiotics and implant retention. During the follow-up period, MRSE-related SSIs in seven of the eight patients were resolved with implant retention and antibiotics without the need for further surgical intervention. One patient did not complete the antibiotic course because of side effects, and implant removal was required to control the infection.

CONCLUSION

Early detection, surgical debridement, and administration of appropriate antibiotics for a suitable duration enabled infection control without the need for implant removal in the treatment of MRSE-related SSI after SI surgery.

LEVEL OF EVIDENCE

4.

Lymphopenia at 4 Days Postoperatively Is the Most Significant Laboratory Marker for Early Detection of Surgical Site Infection Following Posterior Lumbar Instrumentation Surgery

Study Design

Case control study.

Purpose

To identify the most significant laboratory marker for early detection of surgical site infection (SSI) using multiple logistic regression analysis.

Overview of Literature

SSI is a serious complication of spinal instrumentation surgery. Early diagnosis and treatment are crucial.

Methods

We retrospectively reviewed the laboratory data of patients who underwent posterior lumbar instrumentation surgery for degenerative spinal disease from January 2003 to December 2014. Six laboratory markers for early SSI detection were considered: renewed elevation of the white blood cell count, higher at 7 than 4 days postoperatively; renewed elevation of the C-reactive protein (CRP) level, higher at 7 than 4 days postoperatively; CRP level of >10 mg/dL at 4 days postoperatively; neutrophil percentage of >75% at 4 days postoperatively; lymphocyte percentage of <10% at 4 days postoperatively; and lymphocyte count of <1,000/µL at 4 days postoperatively.

Results

Ninety patients were enrolled; five developed deep SSI. Multivariate regression analysis showed that a lymphocyte count of <1,000/µL at 4 days postoperatively was the sole significant independent laboratory marker for early detection of SSI (p=0.037; odds ratio, 11.9; 95% confidence interval, 1.2–122.7).

Conclusions

A lymphocyte count of <1,000/µL at 4 days postoperatively is the most significant laboratory marker for early detection of SSI.

Relationship between preoperative serum rapid turnover proteins and early-stage surgical wound infection after spine surgery

PURPOSE

Malnutrition is one of the important risk factors for postoperative complications. Transferrin, prealbumin, and retinol-binding protein, so-called rapid turnover proteins (RTPs), may be the better indicators for early detection of nutritional deficits. However, few studies have described the impact of serum RTP levels on postoperative surgical site infection (SSI) in spine surgery. The purpose of this study was to investigate the relationship between preoperative serum RTPs and postoperative SSI.

METHODS

The data of 105 patients (64 male, 41 female; average age 64.4 years; age range 20-88 years) who underwent spine surgery in a single institution between 2014 and 2015 were retrospectively analyzed. Preoperative total lymphocyte count, serum albumin, transferrin, prealbumin, retinol-binding protein, pre-and postopeartive C-reactive protein (CRP), white blood cell count (WBC), and total lymphocyte count were evaluated. Postoperative CRP, WBC, and total lymphocyte count were repeated two or three times/week until hospital discharge. A broad spectrum penicillin or second generation cephalosporin was administered as a prophylactic antibiotic to each patient. When repeated CRP elevation or lymphopenia (no more than 10% or 1000/μL) after postoperative day 3 or 4 was observed, possible SSI was diagnosed. Variables between possible SSI group and non-SSI group were compared using Mann-Whitney U or Chi square test. All variables on univariate analysis were included in multiple logistic regression analysis to identify risk factors for possible postoperative SSI.

RESULTS

Thirty-five patients were diagnosed with possible SSI. The mean operative time of possible SSI group was significantly longer (p = 0.036), preoperative total lymphocyte count and serum prealbumin level of possible SSI group were significantly lower (p = 0.002, p = 0.048, respectively) than that of non-SSI group. On univariate analysis, operative time (p = 0.012), preoperative total lymphocyte count (p = 0.041), serum albumin level (p = 0.038), and serum prealbumin level (p = 0.044) were significant contributors to possible SSI, and multiple logistic regression analysis revealed that operative time was the significant contributor to possible SSI (odds ratio 1.008, 95% confidence interval (CI) 1.001-1.015, p = 0.024).

CONCLUSIONS

A low prealbumin level is a possible risk factor for early-stage SSI in spine surgery, though it was not statistically significant; operative time was the most important indicator of SSI on multivariate analysis.

Lymphocyte Count at 4 Days Postoperatively and CRP Level at 7 Days Postoperatively: Reliable and Useful Markers for Surgical Site Infection Following Instrumented Spinal Fusion

STUDY DESIGN

A case-control study.

OBJECTIVE

The objective of this study is to identify biochemical markers for surgical site infection (SSI) in posterior instrumented spinal fusion that are not affected by operative circumstances and to determine diagnostic cutoffs for these markers.

SUMMARY OF BACKGROUND DATA

Numerous biochemical markers may be used for early detection of SSI; however, these markers may be affected by operative factors.

METHODS

We reviewed data on C-reactive protein level and total white blood cell count and differential count before instrumented spinal fusion and at 1, 4, and 7 days postoperatively. The 141 patients in our sample were divided into an SSI group (patients who developed deep SSI) and a no-SSI group. We determined which markers differed significantly between groups and identified those not affected by operative circumstances (operating time, intraoperative blood loss, number of fusion segments) in the no-SSI group. Then, we determined diagnostic cutoffs for these unaffected markers by using receiver-operating characteristic curves.

RESULTS

Three markers were selected: lymphocyte count at 4 days postoperatively (cutoff 1180/μL, sensitivity 90.9%, specificity 65.4%, area under the curve [AUC] 0.80), lymphocyte count of at 7 days postoperatively (cutoff <1090/μL, sensitivity 63.6%, specificity 78.5%, AUC 0.77), and C-reactive protein level at 7 days postoperatively (cutoff >4.4 mg/dL, sensitivity 90.9%, specificity 89.2%, AUC 0.95).

CONCLUSION

Lymphocyte count at 4 and 7 days postoperatively and C-reactive protein level at 7 days postoperatively are reliable markers for SSI following instrumented spinal fusion. Lymphocyte count at 4 days should be useful for screening because of its high sensitivity and because it can be measured early. C-reactive protein level at 7 days should be useful for definitive diagnosis given its high sensitivity and specificity and large AUC.

LEVEL OF EVIDENCE

4.

Lymphopenia and Elevated Blood C-Reactive Protein Levels at Four Days Postoperatively Are Useful Markers for Early Detection of Surgical Site Infection Following Posterior Lumbar Instrumentation Surgery

STUDY DESIGN

Case-control study.

PURPOSE

To identify the characteristics of candidate indexes for early detection of surgical site infection (SSI).

OVERVIEW OF LITERATURE

SSI is a serious complication of spinal instrumentation surgery. Early diagnosis and treatment are crucial for the welfare of the patient postoperation.

METHODS

We retrospectively reviewed laboratory data of patients who underwent posterior lumbar instrumentation surgery for degenerative spine disease. The sensitivity and specificity of six laboratory markers for early detection of SSI were calculated: greater elevation of the white blood cell count at day 7 than at day 4 postoperatively, greater elevation of the C-reactive protein (CRP) level at day 7 than at day 4 postoperatively, a CRP level of >10 mg/dL at 4 days postoperatively, neutrophil percentage of >75% at 4 days postoperatively, a lymphocyte percentage of <10% at 4 days postoperatively, and a lymphocyte count of <1,000/µL at 4 days postoperatively. Statistical analysis was via Fisher's exact test and a p-value of <0.05 was considered significant.

RESULTS

In total, 85 patients were enrolled. Of these, five patients developed deep SSI. The sensitivity and specificity of each index were as follows: index 1, 20.0% and 77.5%; index 2, 20.0% and 83.8%; index 3, 40.0% and 97.5%; index 4, 40.0% and 86.3%; index 5, 0% and 96.3%; and index 6, 80.0% and 80.0%. A significant difference was noted for indexes 3 and 6.

CONCLUSIONS

A CRP level of >10 mg/dL at 4 days postoperatively would be useful for definitive diagnosis of SSI, and a lymphocyte count of <1,000/µL at 4 days postoperatively would be a useful screening test for SSI. Although laboratory markers for early detection of SSI have been frequently reported, we believe that it is important to understand the characteristics of each index for a precise diagnosis.

Surgical Site Infections After Pediatric Spine Surgery

Surgical site infection (SSI) after spinal deformity surgery is a complication in the pediatric population resulting in high morbidity and cost. Despite modern surgical techniques and preventative strategies, the incidence remains substantial, especially in the neuromuscular population. This review focuses on recent advancements in identification of risk factors, prevention, diagnosis, and treatment strategies for acute and delayed pediatric spine infections. It reviews recent literature, including the best practice guidelines for infection prevention in high-risk patients. Targets of additional research are highlighted to assess efficacy of current practices to further reduce risk of SSI in pediatric patients with spinal deformity.

Postoperative complications of spine surgery

A variety of surgical approaches are available for the treatment of spine diseases. Complications can arise intraoperatively, in the immediate postoperative period, or in a delayed fashion. These complications may lead to severe or even permanent morbidity if left unrecognized and untreated [1-4]. Here we review a range of complications in the early postoperative period from more benign complications such as postoperative nausea and vomiting (PONV) to more feared complications leading to permanent loss of neurological function or death [5]. Perioperative pain management is covered in a separate review (Chapter 8).

Efficacy of Antibiotics Sprayed into Surgical Site for Prevention of the Contamination in the Spinal Surgery

Study Design

Retrospective study.

Purpose

To evaluate the effect of intraoperative wound application of vancomycin on preventing surgical wound contamination during instrumented lumbar spinal surgery.

Overview of Literature

Postoperative infection is the one of the most devastating complications of lumbar surgery. There are a few reports showing the benefits of intraoperative wound application of vancomycin during spinal surgery. However, there is no report about the effectiveness of local vancomycin instillation in prevention of surgical wound contamination.

Methods

Eighty-six patients underwent instrumented lumbar spinal surgery. Mean patient age was 65.19 years (range, 23-83 years). There were 67 females and 19 males. During surgery, vancomycin powder was applied into the surgical site before closure in 43 patients (antibiotic group) and vancomycin powder was not applied into the surgical site before closure in 43 patients (control group). The tip of the surgical drain was cultured to evaluate surgical wound contamination. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were measured on the first, third, seventh, and fourteenth day after the operation.

Results

We found two patients with a positive culture from the tip of surgical drains in the antibiotic group, and one patient with a positive culture from the tip of the surgical drain in the control group. Postoperative ESR and CRP levels did not show significant differences between the two groups. On the third postoperative day, ESR in patients of the antibiotic group was more significantly decreased than that in patients of the control group, while CRP level did not show a significant difference between the two groups.

Conclusions

There was no evidence to suggest that intraoperative vancomycin application is effective in decreasing the risk of postoperative wound infection after instrumented posterior lumbar fusion surgery.

Routine clinical markers of the magnitude of the systemic inflammatory response after elective operation: a systematic review

BACKGROUND

Operative injury to the body from all procedures causes a stereotypical cascade of neuroendocrine, cytokine, myeloid, and acute phase responses. This response has been examined commonly by the use of cortisol, interleukin-6 (IL-6), white cell count, and C-reactive protein (CRP). We aimed to determine which markers of the systemic inflammatory response were useful in determining the magnitude of injury after elective operations.

METHODS

A systematic review of the literature was performed using surgery, endocrine response, systemic inflammatory response, cortisol, IL-6, white cell count, and CRP. For each analyte the studies were grouped according to whether the operative injury was considered to be minor, moderate, or major and then by the operative procedure.

RESULTS

A total of 164 studies were included involving 14,362 patients. The IL-6 and CRP responses clearly were associated with the magnitude of operative injury and the invasiveness of the operative procedure. For example, the peak CRP response increased from 52 mg/L with cholecystectomy to 123 mg/L with colorectal cancer resection, 145 mg/L with hip replacement, 163 mg/L after abdominal aortic aneurysm repair, and 189 mg/L after open cardiac surgery. There also appeared to be a difference between minimally invasive/laparoscopic and open procedures such as cholecystectomy (27 vs 80 mg/L), colorectal cancer resection (97 vs 133 mg/L), and aortic aneurysm repair (132 vs 180 mg/L).

CONCLUSION

Peak IL-6 and CRP concentrations consistently were associated with the magnitude of operative injury and operative procedure. These markers may be useful in the objective assessment of which components of Enhanced Recovery after Surgery are likely to improve patient outcome and to assess the possible impact of operative injury on immune function.

Sequential Changes of Plasma C-Reactive Protein, Erythrocyte Sedimentation Rate and White Blood Cell Count in Spine Surgery : Comparison between Lumbar Open Discectomy and Posterior Lumbar Interbody Fusion

Objective

C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are often utilized to evaluate for postoperative infection. Abnormal values may be detected after surgery even in case of non-infection because of muscle injury, transfusion, which disturbed prompt perioperative management. The purpose of this study was to evaluate and compare the perioperative CRP, ESR, and white blood cell (WBC) counts after spine surgery, which was proved to be non-infection.

Methods

Twenty patients of lumbar open discectomy (LOD) and 20 patients of posterior lumbar interbody fusion (PLIF) were enrolled in this study. Preoperative and postoperative prophylactic antibiotics were administered routinely for 7 days. Blood samples were obtained one day before surgery and postoperative day (POD) 1, POD3, and POD7. Using repeated measures ANOVA, changes in effect measures over time and between groups over time were assessed. All data analysis was conducted using SAS v.9.1.

Results

Changes in CRP, within treatment groups over time and between treatment groups over time were both statistically significant F(3,120)=5.05, p=0.003 and F(1,39)=7.46, p=0.01, respectively. Most dramatic changes were decreases in the LOD group on POD3 and POD7. Changes in ESR, within treatment groups over time and between treatment groups over time were also found to be statistically significant, F(3,120)=6.67, p=0.0003 and F(1,39)=3.99, p=0.01, respectively. Changes in WBC values also were be statistically significant within groups over time, F(3,120)=40.52, p<0.001, however, no significant difference was found in between groups WBC levels over time, F(1,39)=0.02, p=0.89.

Conclusion

We found that, dramatic decrease of CRP was detected on POD3 and POD7 in LOD group of non-infection and dramatic increase of ESR on POD3 and POD7 in PLIF group of non-infection. We also assumed that CRP would be more effective and sensitive parameter especially in LOD than PLIF for early detection of infectious complications. Awareness of the typical pattern of CRP, ESR, and WBC may help to evaluate the early postoperative course.

Is Minimally Invasive Spine Surgery Also Minimally Pro-Inflammatory? Muscular Markers, Inflammatory Parameters and Cytokines to Quantify the Operative Invasiveness Assessment in Spine Fusion

Over the last decades, minimally invasive surgery (MIS) techniques entered in the surgical routine due to their major advantage in reducing the unnecessary exposure of tissue and, thus, the trauma. Even in the context of orthopedics and spine surgery these practices have been widely developed and applied. Besides the clinical outcome of the patients, few studies have quantitatively assessed the traumatic and inflammatory effects of a specific surgical technique. Indeed, currently, a universally accepted biological outcome measure, such as a panel of biochemical markers, to define the success of MIS approach is still lacking. We reviewed the literature to collect the published data regarding the quantitative analysis of trauma induced by either conventional or minimally invasive surgery with the aim of highlighting evidence useful to guide future studies. Previous publications show some evidence in support of the hypothesis that MIS approaches are less traumatic, and possibly less pro-inflammatory, than conventional ones. Creatin kinase (as a marker of muscular damage) and C-reactive protein (as a marker of systemic inflammation) seem to reproducibly follow different trends in minimally invasive surgery compared to conventional procedures. Moreover, cytokines, such as interleukin (IL)-6 and IL-10 are also promising markers in this context.

Surgical site infections following spine surgery: eliminating the controversies in the diagnosis

Surgical site infection (SSI) following spine surgery is a dreaded complication with significant morbidity and economic burden. SSIs following spine surgery can be superficial, characterized by obvious wound drainage or deep-seated with a healed wound. Staphylococcus aureus remains the principal causal agent. There are certain pre-operative risk factors that increase the risk of SSI, mainly diabetes, smoking, steroids, and peri-operative transfusions. Additionally, intra-operative risk factors include surgical invasiveness, type of fusion, implant use, and traditional instead of minimally invasive approach. A high level of suspicion is crucial to attaining an early definitive diagnosis and initiating appropriate management. The most common presenting symptom is back pain, usually manifesting 2–4 weeks and up to 3 months after a spinal procedure. Scheduling a follow-up visit between weeks 2 and 4 after surgery is therefore necessary for early detection. Inflammatory markers are important diagnostic tools, and comparing pre-operative with post-operative levels should be done when suspecting SSIs following spine surgery. Particularly, serum amyloid A is a novel inflammatory marker that can expedite the diagnosis of SSIs. Magnetic resonance imaging remains the diagnostic modality of choice when suspecting a SSI following spine surgery. While 18F-fluorodeoxyglucose-positron emission tomography is not widely used, it may be useful in challenging cases. Despite their low yield, blood cultures should be collected before initiating antibiotic therapy. Samples from wound drainage should be sent for Gram stain and cultures. When there is a high clinical suspicion of SSI and in the absence of superficial wound drainage, computed tomography-guided aspiration of paraspinal collections is warranted. Unless the patient is hemodynamically compromised, antibiotics should be deferred until proper specimens for culture are secured.

Normal behavior of plasma procalcitonin in adolescents undergoing surgery for scoliosis

Background and Aims:

Surgical site infections are relatively common after spinal deformity surgery. Early detection of deep wound infections is important, since it may allow retention of spinal instrumentation. However, serum C-reactive protein and erythrocyte sedimentation rate may remain elevated for almost 6 weeks, making differential diagnosis of systemic inflammatory response and acute deep bacterial wound infection difficult. Plasma procalcitonin has been suggested to be a useful indicator for bacterial infection. However, there are no studies evaluating behavior of procalcitonin in patients undergoing major spine surgery with instrumentation.

Materials and Methods:

A total of 50 consecutive adolescents (37 idiopathic scoliosis and 13 neuromuscular scoliosis, mean age = 15 years at surgery and follow-up time = 21 months (range = 12–29 months)) undergoing scoliosis surgery participated in this prospective follow-up study. White blood cell count, serum C-reactive protein, and plasma procalcitonin levels were measured on the day before surgery, on the day of surgery, and daily thereafter for 1 week. None of the patients developed signs of acute or delayed wound infection during the follow-up period; however, two neuromuscular scoliosis patients developed severe postoperative pneumonia, and their inflammatory parameter data will be reported separately.

Results:

Plasma procalcitonin levels peaked on the first postoperative day (mean = 0.19 ng/mL, range = 0.04–1.29 ng/mL), and mean values were less than 0.5 ng/mL during the whole first postoperative week, while C-reactive protein remained elevated during the whole first postoperative week (highest mean value = 63.8 mg/L (range = 5–248 mg/L) on third postoperative day). Patients with idiopathic scoliosis had lower C-reactive protein levels (p < 0.05 from first to sixth postoperative day) and lower procalcitonin levels (p < 0.05 from third to seventh postoperative day) than neuromuscular scoliosis patients. Two patients with postoperative pneumonia showed elevated procalcitonin values over the whole postoperative week (22.34 ng/mL and 0.72 ng/mL highest values, respectively).

Conclusions:

Elevated plasma procalcitonin levels seem useful when excluding acute deep wound infection from systemic inflammatory response.

Endoscopy-assisted posterior lumbar interbody fusion in a single segment

Posterior lumbar interbody fusion (PLIF) has been routinely performed for the treatment of lumbar segmental lesions. However, traditional PLIF procedures can result in a variety of approach-related morbidities. The purpose of this study was to determine the efficacy of endoscopy-assisted PLIF in lumbar arthrodesis. From July 2005 to May 2007, a total of 56 patients underwent PLIF, including 24 endoscopy-assisted operations (endoscopic group) and 32 traditional open operations (open group). The perioperative data, clinical outcomes and radiographic results were compared. The intraoperative bleeding volume, postoperative drainage volume, intraoperative and postoperative allogeneic blood transfusion volumes, values for C-reactive protein and erythrocyte sedimentation rate on postoperative day 3 and postoperative hospitalization days were decreased in the endoscopic group (p<0.05), while the operative time was longer than that of the open group (p=0.026). According to the Visual Analog Scale for pain, the postoperative low back pain score in the endoscopic group was lower than that observed in the open group (p<0.05). In the endoscopic group, the excellent and good outcome rate was 87.5%, the incidence of complications was 8.3%, and the intervertebral fusion rate was 100%. There were no significant differences for these outcomes when compared with the open group (p>0.05). Endoscopy-assisted PLIF can achieve a clinical efficacy similar to that of traditional open operations while minimizing destruction to adjacent tissues. This technique is safe and is characterized by less bleeding, less tissue trauma, decreased postoperative pain, rapid recovery, and a shorter postoperative hospital stay.

Elevated serum lactoferrin and neopterin are associated with postoperative infectious complications in patients with acute traumatic spinal cord injury

INTRODUCTION

Several studies have shown that lactoferrin (LF) and neopterin (NT) are correlated with infection. The aim of this study is to determine whether serum levels of LF and NT are associated with postoperative infectious complications in patients with acute traumatic spinal cord injury.

MATERIAL AND METHODS

A total of 268 patients with acute traumatic spinal cord injury who underwent spinal surgery were enrolled in this study. Serum levels of LF, NT, and C-reactive protein (CRP), in addition to white blood cell count (WBC) and erythrocyte sedimentation rate (ESR), were measured preoperatively and 24 h postoperatively.

RESULTS

In total, 22 of 268 patients (8.2%) developed postoperative infectious complications. The levels of serum LF, NT, and CRP were significantly higher in the infected patients than in the non-infected patients. No significant differences were observed in postoperative WBC count and ESR between the two groups. Multivariate logistic regression revealed that LF (OR: 1.004 (1.002-1.007)), NT (OR: 1.137 (1.054-1.227)), and CRP (OR: 1.023 (1.002-1.044)) were significantly associated with the presence of postoperative infectious complications. The area under receiver operating characteristic curves for LF, NT, and CRP was 0.709, 0.779, and 0.629, respectively.

CONCLUSIONS

Elevated serum concentrations of LF and NT are associated with early infection after surgery. Compared to CRP, elevated levels of LF and NT are better indicators for predicting postoperative infectious complications in patients with acute traumatic spinal cord injury.

Infection with spinal instrumentation: Review of pathogenesis, diagnosis, prevention, and management

Background:

Instrumentation has become an integral component in the management of various spinal pathologies. The rate of infection varies from 2% to 20% of all instrumented spinal procedures. Every occurrence produces patient morbidity, which may adversely affect long-term outcome and increases health care costs.

Methods:

A comprehensive review of the literature from 1990 to 2012 was performed utilizing PubMed and several key words: Infection, spine, instrumentation, implant, management, and biofilms. Articles that provided a current review of the pathogenesis, diagnosis, prevention, and management of instrumented spinal infections over the years were reviewed.

Results:

There are multiple risk factors for postoperative spinal infections. Infections in the setting of instrumentation are more difficult to diagnose and treat due to biofilm. Infections may be early or delayed. C Reactive Protein (CRP) and Magnetic Resonance Imaging (MRI) are important diagnostic tools. Optimal results are obtained with surgical debridement followed by parenteral antibiotics. Removal or replacement of hardware should be considered in delayed infections.

Conclusions:

An improved understanding of the role of biofilm and the development of newer spinal implants has provided insight in the pathogenesis and management of infected spinal implants. This literature review highlights the mechanism, pathogenesis, prevention, and management of infection after spinal instrumentation. It is important to accurately identify and treat postoperative spinal infections. The treatment is often multimodal and prolonged.

Diagnostic usefulness of white blood cell and absolute neutrophil count for postoperative infection after anterior cervical discectomy and fusion using allograft and demineralized bone matrix

Study Design

Prospective study.

Purpose

We investigated normative temporal levels of white blood cell (WBC) and absolute neutrophil count (ANC) in uncomplicated anterior cervical discectomy and fusion (ACDF) using allograft and demineralized bone matrix (DBM).

Overview of Literature

No study has investigated the diagnostic usefulness of WBC and ANC for postoperative infection following ACDF using allograft and DBM.

Methods

Blood samples of 85 patients, who underwent one or two-level ACDF, were obtained and evaluated before surgery and on the first, third, fifth, seventh, fourteenth, thirtieth, and ninetieth postoperative days. No infection was found in all patients for at least one year follow-up period.

Results

Mean WBC and ANC values increased significantly and reached peak levels on the first postoperative day. The peaked levels rapidly decreased but still remained elevated above the preoperative levels on the third postoperative day. The levels returned close to the preoperative levels on the fifth postoperative day. The mean WBC and ANC values did not get out of their normal reference ranges throughout the follow-up periods. One-level and two-level ACDF exhibited a similar course of postoperative changes in WBC and ANC values and no significant difference in mean levels of WBC and ANC throughout the follow-up periods.

Conclusions

Uncomplicated ACDF using allograft and DBM showed normal values of WBC and ANC during the early postoperative period. Therefore, significant abnormal values of WBC and ANC at an early postoperative period suggest the possibility of the development of acute postoperative infection after ACDF using allograft and DBM.

Normal range of the inflammation related laboratory findings and predictors of the postoperative infection in spinal posterior fusion surgery

BACKGROUND

Inflammation related hematological parameters vary greatly depending on patients. It is not well known how much increase of which parameter warrants suspicion of postoperative infection. This study proposes to identify the normal range and the predictive factors for postoperative infection by conducting a time series analysis of the hematological parameters of patients after the spinal posterior fusion.

METHODS

A retrospective study was done with 608 patients who underwent spinal posterior fusion with pedicle screw fixation. Laboratory assessment including the leucocyte, neutrophil, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) of patients for 2 weeks after operation. The patients were divided into the one-level fusion group (group I), the two-level fusion group (group II), the three or multi-level fusion or reoperation group (group III), and the postoperative infection group (group IV). Blood was drawn before breakfast prior to the operation, and then 2-3 days, 4-7 days, 8-11 days, and 12-14 days after the operation. The leucocyte count, neutrophil count, CRP, and ESR were measured.

RESULTS

From 4-7 days after the operation, the CRP and neutrophil count of group IV were significantly higher than those of group I and II, and from 8-11 days after operation, the CRP and neutrophil counts were significantly higher than those of all groups. Twelve to fourteen days after the operation, the neutrophil count of group IV was significantly higher than that of group I and II, while the neutrophil count of group III was also higher than that of group I. The lower limit of the 95% confidence interval (CI) of the CRP and neutrophil count group IV was greater than the upper limit of the 95% CI of group I and II. The ESR of group IV was significantly higher than that of group I and III.

CONCLUSIONS

If the postoperative CRP and neutrophil counts are high, or if the CRP begins to rise again 8 days after the operation, the likelihood of infection increases, but caution must be exercised in interpreting the results. If the hematological parameters are higher than the lower limit of the 95% CI of the postoperative infection group, infection must be strongly suspected.

Postoperative changes of early-phase inflammatory indices after uncomplicated anterior cervical discectomy and fusion using allograft and demineralised bone matrix

PURPOSES

We investigated sequential levels of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) in uncomplicated ACDF (anterior cervical discectomy and fusion) using allograft and DBM (demineralised bone matrix) for primary cervical spondylosis and/or disc herniation. To our knowledge, there has been no study to investigate the diagnostic value of CRP and ESR for postoperative infection in ACDF using allograft and DBM.

METHODS

Blood samples of 85 patients, who underwent one- (n = 51) or two-level (n = 34) ACDF, were obtained and evaluated before surgery and on the first, third, fifth, seventh, 14th, 30th, and 90th postoperative days. No infection was found in any patient for at least one year follow-up period.

RESULTS

Mean CRP value increased significantly on the first postoperative day and reached a peak on the third postoperative day. The peak level rapidly decreased but remained elevated on the fifth, seventh, and 14th postoperative days. Mean ESR value increased significantly and reached a peak on the third postoperative day. The peak level gradually decreased but remained elevated on the fifth and seventh postoperative days. One- and two-level ACDF exhibited similar postoperative changes in CRP and ESR values and no significant difference in mean levels of CRP and ESR throughout the follow-up periods.

CONCLUSIONS

This study demonstrates that uncomplicated ACDF using allograft and DBM showed significant abnormal values of CRP and ESR during the early postoperative period. This result suggests that abnormal values of CRP and ESR in the early postoperative period do not indicate acute postoperative infection after ACDF using allograft and DBM. Straying from the normal course, such as a second rise or a failure to decrease, of CRP and ESR is more important to signpost acute postoperative infection in ACDF using allograft and DBM.

Spondylodiscitis: standards of current treatment

BACKGROUND

Spinal infections are an important clinical problem that often require aggressive medical therapy, and sometimes even surgery. Known risk factors are advanced age, diabetes mellitus, rheumatoid arthritis, immunosuppression, alcoholism, long-term steroid use, concomitant infections, poly-trauma, malignant tumor, and previous surgery or invasive procedures (discography, chemonucleolysis, and surgical procedures involving or adjacent to the intervertebral disc space). The most common level of involvement is at the lumbar spine, followed by the thoracic, cervical and sacral levels: lesions at the thoracic spine tend to lead more frequently to neurological symptoms.

OBJECTIVE

The aim of the current paper is to describe current evidence-based standards of therapy in the management of SD by emphasizing pharmacological therapy and principles and indications for bracing and surgery.

METHODS

A PubMed and Google Scholar search using various forms and combinations of the key words: spondylodiscitis, spine, infection, therapy, surgery, radiology, treatment. Reference citations from publications identified in the literature search were reviewed. Publications highlighted in this article were extracted based on relevancy to established, putative, and emerging diagnostic and therapeutic standards, either conservative (antibiotic therapy and bracing) or surgical.

FINDINGS

To date, conservative therapy, based on targeted antibiotic therapy plus bracing, represents the mainstay in the management of SD. Proper diagnosis and tailored therapy can improve clinical results and decrease the chance of failure. Surgery should be an option only for patients with complications of this disease, namely deformity, neural compression and neurological compromise. Current standards in the setting of SD are continuously evolving, as can be seen in the recent advances in the field of radiological diagnostics, and the use of growth factors and cell-therapy strategies to promote infection eradication and bone healing after surgery.

The utility of erythrocyte sedimentation rate values and white blood cell counts after spinal deformity surgery in the early (≤3 months) post-operative period

PURPOSE

The erythrocyte sedimentation rate (ESR) and white blood cell (WBC) count are frequently obtained in the work-up of post-operative fever. However, their diagnostic utility depends upon comparison with normative peri-operative trends which have not yet been described. The purpose of this study is to define a range of erythrocyte sedimentation rates and white blood cell counts following spinal instrumentation and fusion in non-infected patients.

METHODS

Seventy-five patients underwent spinal instrumentation and fusion. The erythrocyte sedimentation rate and white blood cell count were recorded pre-operatively, at 3 and 7 days post-operatively, and at 1 and 3 months post-operatively.

RESULTS

Both erythrocyte sedimentation rate and white blood cell count trends demonstrated an early peak, followed by a gradual return to normal. Peak erythrocyte sedimentation rates occurred within the first week post-operatively in 98% of patients. Peak white blood cell counts occurred with the first week in 85% of patients. In the absence of infection, the erythrocyte sedimentation rate was abnormally elevated in 78% of patients at 1 month and in 53% of patients at 3 months post-operatively. The white blood cell count was abnormally elevated in only 6% of patients at 1 month post-operatively. Longer surgical time was associated with elevated white cell count at 1 week post-operatively. The fusion of more vertebral levels had a negative relationship with elevated erythrocyte sedimentation rate at 1 week post-operatively. The anterior surgical approach was associated with significantly lower erythrocyte sedimentation rate at 1 month post-operatively and with lower white cell count at 1 week post-operatively.

CONCLUSION

In non-infected spinal fusion surgeries, erythrocyte sedimentation rates are in the abnormal range in 78% of patients at 1 month and in 53% of patients at 3 months post-operatively, suggesting that the erythrocyte sedimentation rate is of limited diagnostic value in the early post-operative period.

Infections in spinal instrumentation

Surgical-site infection (SSI) in the spine is a serious postoperative complication. Factors such as posterior surgical approach, arthrodesis, use of spinal instrumentation, age, obesity, diabetes, tobacco use, operating-room environment and estimated blood loss are well established in the literature to affect the risk of infection. Infection after spine surgery with instrumentation is becoming a common pathology. The reported infection rates range from 0.7% to 11.9%, depending on the diagnosis and complexity of the procedure. Besides operative factors, patient characteristics could also account for increased infection rates. These infections after instrumented spinal fusion are particularly difficult to manage due to the implanted, and possibly infected, instrumentation. Because the medical, economic and social costs of SSI after spinal instrumentation are enormous, any significant reduction in risks will pay dividends. The goal of this literature review was to analyse risk factors, causative organisms, diagnostic elements (both clinical and biological), different treatment options and their efficiency and consequences and the means of SSI prevention.

Bacterial wound contamination during simple and complex spinal procedures. A prospective clinical study

BACKGROUND CONTEXT

Spinal procedures have a potential of intraoperative contamination. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) have been used to diagnose postoperative infections after spinal surgery. However, it has not been demonstrated if there is an association between surgical site contamination and clinical manifestation of postoperative infection based on inflammatory markers and patients' clinical course.

PURPOSE

The purpose of this prospective study was to evaluate the association between surgical site contamination and the development of a postoperative infection in simple and complex surgical procedures. C-reactive protein and ESR levels were observed. The correlation between their values, surgical time, type of surgical procedures, and contaminated surgical sites was investigated.

STUDY DESIGN

Prospective clinical study.

PATIENT SAMPLE

The study consisted of 40 patients divided into two groups. Group A included 20 patients (mean age, 46.2 years; 12 women and 8 men) who underwent an open discectomy for a lumbar herniated disc. Group B consisted of 20 patients (mean age, 67.9 years; 11 women and 9 men) who underwent a decompression and instrumented fusion for lumbar spinal stenosis. They were followed up for an average of 26.7 months (range, 11-40 months).

OUTCOME MEASURES

Samples were obtained for cultures in standard time intervals during surgery. The types of bacteria cultured were evaluated, and CRP and ESR levels were measured.

METHODS

Simple lumbar discectomy (Group A, 20 patients) and instrumented lumbar decompression for degenerative lumbar stenosis (Group B, 20 patients) were performed in a prospective consecutive series of patients. All patients were operated by the same surgeon in the same operating room. Surgical site preparation in each patient was done by a standard manner. Samples were obtained for cultures in standard time intervals during surgery. C-reactive protein and ESR levels were measured preoperatively on the 3rd, 7th, and 21st postoperative days, and the clinical course of each patient was recorded.

RESULTS

From 40 patients, three patients in Group A and five patients in Group B, a total of eight patients (20%) had positive cultures for bacteria. There was no statistical significance between contamination and duration of surgery in both groups. None of the patients with positive intraoperative cultures developed any clinical signs of superficial or deep postoperative spinal infection, and no additional antibiotic treatment was administered. Three patients with negative cultures developed a postoperative infection. There were no differences in CRP and ESR values between patients with contamination and noncontamination in both groups. C-reactive protein and ESR levels were significantly elevated in complex procedures (Group B) than in simple procedures (Group A). Statistical analysis of CRP and ESR values in both groups and types of bacteria cultured intraoperatively are presented.

CONCLUSIONS

The results of this study demonstrate that intraoperative contamination can occur during simple and complex spinal procedures. In the absence of postoperative signs of infection in patients with intraoperative contamination, there is no need of continuing antibiotic treatment. Postoperative kinetics of CRP and ESR showed to be the same in patients with and without intraoperative contamination. Higher levels of inflammatory markers were noted in complex spinal procedures where instrumentation was applied.

CRP and leukocyte-count after lumbar spine surgery: fusion vs. nucleotomy

BACKGROUND

Despite the fact that C-reactive protein (CRP) levels and white blood cell (WBC) count are routine blood chemistry parameters for the early assessment of wound infection after surgical procedures, little is known about the natural history of their serum values after major and minimally invasive spinal procedures.

METHODS

Pre- and postoperative CRP serum levels and WBC count in 347 patients were retrospectively assessed after complication-free, single-level open posterior lumbar interlaminar fusion (PLIF) (n = 150) for disc degeneration and spinal stenosis and endoscopically assisted lumbar discectomy (n = 197) for herniated lumbar disc. Confounding variables such as overweight, ASA classification, arterial hypertension, diabetes mellitus, and perioperative antibiotics were recorded to evaluate their influence on the kinetics of CRP values and WBC count postoperatively.

RESULTS

In both procedures, CRP peaked 2-3 days after surgery. The maximum CRP level was significantly higher after fusion: mean 127 (SD 57) (p < 0.001). A rapid fall in CRP within 4-6 days was observed for both groups, with almost normal values being reached after 14 days. Only BMI > 25 and long duration of surgery were associated with higher peak CRP values. WBC count did not show a typical and therefore interpretable profile.

CONCLUSION

CRP is a predictable and responsive serum parameter in postoperative monitoring of inflammatory responses in patients undergoing spine surgery, whereas WBC kinetics is unspecific. We suggest that CRP could be measured on the day before surgery, on day 2 or 3 after surgery, and also between days 4 and 6, to aid in early detection of infectious complications.