Risk factors for surgical site infection in elective routine degenerative lumbar surgeries

Prediction models for risk assessment of surgical site infection after spinal surgery: A systematic review

Background

Spinal surgeries are a common procedure, but there is significant risk of adverse events following these operations. While the rate of adverse events ranges from 8% to 18%, surgical site infections (SSIs) alone occur in between 1% and 4% of spinal surgeries.

Methods

We completed a systematic review addressing factors that contribute to surgical site infection after spinal surgery. From the included studies, we separated the articles into groups based on whether they propose a clinical predictive tool or model. We then compared the prediction variables, model development, model validation, and model performance.

Results

About 47 articles were included in this study: 10 proposed a model and 5 validated a model. The models were developed from 7,720 participants in total and 210 participants with SSI. Only one of the proposed models was externally validated by an independent group. The other 4 validation papers examined the performance of the ACS NSQIP surgical risk calculator.

Conclusions

While some preoperative risk models have been validated, and even successfully implemented clinically, the significance of postoperative SSIs and the unique susceptibility of spine surgery patients merits the development of a spine-specific preoperative risk model. Additionally, comprehensive and stratified risk modeling for SSI would be of invaluable clinical utility and greatly improve the field of spine surgery.

Effect of pre-operative HbA1c and blood glucose level on the surgical site infection after lumbar instrumentation surgery

BACKGROUND

This study aims to investigate the effect of pre-operative hemoglobin A1c (HbA1c) and pre-operative blood glucose control on the rate of surgical site infection (SSI) after posterior lumbar instrumentation surgery in diabetes mellitus (DM) patients.

METHODS

A total of 1046 patients who had undergone posterior lumbar instrumentation surgery were reviewed. Based on pre-operative HbA1c, patients were divided into three groups: non-DM group, low HbA1c group (HbA1c < 7.0 % in DM) and high HbA1c group (≥7.0). As well, based on the status of blood glucose control in DM patients immediately before surgery, patients were divided into two groups: good control group (post-prandial blood glucose [PBG] < 200 mg/dl) and poor control group (≥200). The rate of SSI was compared among these groups.

RESULTS

SSI occurred in 1.9 % in non-DM group, 2.4 % in low HbA1c group, and 9.3 % in high HbA1c group. Compared with non-DM group, high HbA1c group had significantly higher rate of SSI (p = 0.001). There was not statistically different between non-DM and low HbA1c groups (p = 0.550). SSI occurred in 2.2 % in good control group, and 10.2 % in poor control group. The rate of SSI was significantly lower in good control group (p = 0.013).

CONCLUSION

This study showed that the rate of SSI after posterior lumbar instrumentation surgery tend to be higher in DM patients with high HbA1c. However, the rate might be reduced to the same level as that of non-DM group by lowering PBG to <200 mg/dl immediately before surgery.

Subcutaneous Lumbar Spine Index (SLSI) as a Risk Factor for Surgical Site Infection After Lumbar Fusion Surgery: A Retrospective Matched Case-Control Study

STUDY DESIGN

A retrospective matched case-control study.

OBJECTIVE

This study aims to investigate the value of Subcutaneous Lumbar Spine Index (SLSI) as a predictor of early surgical site infection (SSI) after lumbar intervertebral fusion surgery.

METHODS

A retrospective case-control study was performed on patients who underwent transforaminal lumbar interbody fusion (TLIF) from January 1, 2014 to December 31, 2019 in a single institution. Cases were defined as those who developed early SSI according to the US Center for Disease Control and Prevention criteria, and controls were matched from those patients without early SSI using the following matched criteria: gender, age, time of surgery and diabetes. Subcutaneous fat thickness (SFT) and SLSI were measured on preoperative MRI mid-sagittal T2 weighted images.

RESULTS

A total of 3615 patients who underwent TLIF were enrolled in this study. Thirty-three patients were included in early SSI, and sixty-six patients were selected as matched controls. Univariate analysis indicated that fusion levels (P = .007), operation time (P = .022), obesity (P = .013), SFT (P = .002) and SLSI (P = .001) were significantly associated with early SSI. Multiple logistic regression analysis revealed that multilevel fusion levels (P = .021), obesity (P = .035), a large SFT (P = .026) and a high SLSI (P = .012) were independent risk factors. Body mass index (BMI) and SLSI were moderately correlated (r2 = .55). ROC curve demonstrated that SLSI was more sensitive than SFT to predict the early SSI.

CONCLUSION

SLSI is a novel radiological risk factor for early SSI development and is a better indicator than SFT to predict early SSI risk after lumbar intervertebral fusion.

Establishment and validation of a nomogram model for postoperative surgical site infection after transforaminal lumbar interbody fusion: A retrospective observational study

BACKGROUND

Surgical site infection is one of the serious complications of transforaminal lumbar interbody fusion surgery, and many factors affect its occurrence.

METHODS

A total of 1,277 patients who underwent transforaminal lumbar interbody fusion between 2018 and 2021 were enrolled in this study. Subsequently, 1,277 patients were randomly assigned to a training cohort (N = 958) and a validation cohort (N = 319) in a 3:1 ratio. We developed a nomogram according to the results of binary logistic regression analysis in the training cohort. The nomogram's predictive accuracy and discriminative ability were evaluated by calibration curve and receiver operating characteristic analysis. Decision curve analysis was performed to estimate the clinical value of our nomogram.

RESULTS

In univariate and multivariate analysis, smoking, diabetes, intraoperative blood loss, American Society of Anesthesiologists class ≥III, serum calcium, albumin, and serum glucose were identified as significant independent predictors. The nomogram was developed using these independent predictors, which showed good diagnostic accuracy for surgical site infection of the training and validation cohorts. The calibration curves for the 2 cohorts showed optimal agreement between nomogram prediction and actual observation. The decision curve analysis of the nomogram model showed the great clinical use of the nomogram.

CONCLUSION

The nomogram based on smoking, diabetes, intraoperative blood loss, American Society of Anesthesiologists class, serum calcium, albumin, and serum glucose has the potential as a clinically useful predictive tool of surgical site infection after transforaminal lumbar interbody fusion surgery. It is helpful to visualize the risk factors of surgical site infection.

Complication Pattern of Sacral Primary Tumor Resection: A Study on the Risk Factors of Surgical Site Infection and Bowel or Bladder Dysfunction and Their Associations with Length of Hospital Stay

STUDY DESIGN

Retrospective open cohort study.

PURPOSE

The current study aimed to explore the pattern of complications after primary sacral tumor resection, to investigate the possible effect of several perioperative parameters on the development of complications, and to identify which complications are associated with the length of hospital stay (LOS).

OVERVIEW OF LITERATURE

Primary sacral tumor (pST) resection is associated with a high complication rate. However, the number of studies on these complications and their effect on LOS is limited.

METHODS

The clinical data of 140 patients with pST surgeries and 106 subsequent patients with local recurrence surgeries in four subgroups (index surgery, local recurrence surgery, malignant, and benign tumor) were prospectively collected and analyzed. The prognostic value of several perioperative factors on the development of surgical site infection (SSI), bowel and bladder dysfunction (BBD), and LOS was investigated using the logistic and linear regression models.

RESULTS

The overall complication rates were 61.2% after index surgeries and 50.9% after local recurrence surgeries. The most frequent complications were SSI, vegetative dysfunction, urinary tract infections, and neurological deterioration. Age >55 years, malignant tumors, and red blood cell transfusion had a predictive effect on the development of SSI in the logistic model (p<0.01, R2=0.43). Bilateral S2 or S3 resection commonly caused postoperative BBD (chi-square test=62.5, degrees of freedom=4, p<0.001). In the multiple linear regression model, wound dehiscence, BBD, systemic and urinary tract infection, cerebrospinal fluid leak, and neurologic deterioration were associated with a significantly long LOS (p<0.01, R2=0.62).

CONCLUSIONS

Surgical resection of pSTs has a high complication rate. Its common complications are SSI and BBD, both of which can have a significant influence on global therapeutic outcome. Malignant tumor diagnosis, old age, and red blood cell transfusion can remarkably increase the risk of SSI. Further, the development of BBD is significantly associated with the number of resected sacral nerve roots. By decreasing perioperative complications, LOS can decrease significantly.

Effect of Lower Extremity Osteoarthritis on Outcomes of Lumbar Decompression

BACKGROUND

The purpose of this study is to evaluate how hip or knee osteoarthritis (OA) and total joint arthroplasty impact the outcomes of patients undergoing lumbar decompression.

METHODS

A retrospective review of 342 patients undergoing lumbar decompression without fusion from January 2019 and June 2021 at a single institution was performed. Univariate and multivariate analyses were used to compare outcomes between patients with and without concomitant hip or knee OA.

RESULTS

Forty-six percent of patients had a hip or knee OA diagnosis and were higher risk as they were older, had higher BMIs, were more likely to be former smokers, had higher ASA scores, and were more likely to undergo 3+ level surgery. Postoperatively, after adjusting for differences between groups, hip or knee OA patients were more likely to be readmitted (OR=12.45, p=0.026) or have a complication (OR=13.77, p=0.031). However, patient reported outcomes as measured by Patient Reported Outcomes Measurement Information System-physical function. were similar at 1-3 months and 3-6 months. Higher levels of physical function were observed at 3-6 months postoperatively in hip OA patients with a history of THA.

CONCLUSION

Patients with concomitant hip or knee OA are at higher risk for readmission and postoperative complications but may achieve similar levels of physical function as those without OA.

Complication Pattern After Percutaneous Cement Discoplasty: Identification of Factors Influencing Reoperation and Length of Hospital Stay

OBJECTIVE

Percutaneous cement discoplasty (PCD) was introduced to treat symptomatic vertical instability of the lumbar spine in a minimally invasive way. The aim of the present study was to analyze the complication pattern after PCD and to identify factors that predict the chance of cement leakage, reoperation, and length of hospital stay (LOS).

METHODS

patients were treated with PCD within the study period. Clinical features and complications were analyzed by applying descriptive statistics, whereas perioperative factors predictive of cement leakage, reoperation, and LOS were identified by regression models.

RESULTS

Cement leakage rate was 30.4% in the total cohort; however, only fifth of them were symptomatic. Cement leakage itself did not have a significant influence on clinical outcome. Other complications and nonsurgical adverse events were registered only in 2.0% of cases. Age, subcutaneous fat tissue thickness, low viscosity cement, lower level of surgeon's experience and the number of operated levels were identified as risk factors of cement leakage (P < 0.01; c-index = 0.836). Type of procedure, Charlson comorbidity score, reoperation, and nonsurgical adverse events significantly increased the LOS (P < 0.01). Cement leakage, early surgical practice, and increased subcutaneous fat tissue thickness were risk factors for reoperation (P < 0.01; c-index = 0.72).

CONCLUSIONS

PCD is a relatively safe and effective procedure for treating spinal instability caused by advanced-stage disc degeneration characterized by vacuum phenomenon. Cement leakage is not uncommon but is only a radiologic complication without clinical consequences in most cases. On the other hand, it can increase the LOS and is a significant risk factor for reoperation.

The Percutaneous Endoscopic Lumbar Debridement and Irrigation Drainage Technique for the First-Stage Treatment of Spontaneous Lumbar Spondylodiscitis: A Clinical Retrospective Study

Background

Minimally invasive or open surgery is contentious in the treatment of spondylodiscitis, therefore finding a balance between the two is urgently needed. In this study, we propose a new treatment paradigm for treating spontaneous lumbar spondylodiscitis by percutaneous endoscopic lumbar debridement and irrigation drainage (PELDID). Then, the Pola classification was used to guide subsequent treatment.

Methods

From November 2017 to April 2019, this study collected data on 16 patients with lumbar spondylodiscitis who were surgically treated utilizing this treatment paradigm in our department. Clinical effectiveness was determined using the visual analogue scale (VAS), the Oswestry Disability Index (ODI), the MOS 36-item short-form health survey (SF-36), and Kirkaldy-Willis criteria.

Results

All 16 patients completed the treatment using the above paradigm and were followed up for 28.13 ± 10.15 months. The preoperative Pola classification is as follows: 7 cases of type A, 3 cases of type B, and 6 cases of type C. After the first-stage surgery, the evaluation results of Pola classification were as follows: 8 cases of type A, 8 cases of type B, and 0 cases of type C. Four patients received second-stage surgery with internal fixation through the paravertebral multifidus space approach and intervertebral bone graft fusion through the transforaminal approach, and the reoperation rate was 25% (4/16 cases). The Visual analogue scale (VAS), Oswestry Disability Index (ODI), and SF-36 score all improved significantly from 2.43 ± 0.89 to 0.18 ± 0.40, from 77.31% ± 11.15%to 16.93% ± 5.45%, and from 18.34 ± 7.47 to 80.3 ± 15.36. The CRP and ESR decreased dramatically from 49.61 ± 48.84 to12.50 ± 12.18 and from 65.56 ± 26.89 to 29.68 ± 20.68. There were no recurrences of infection in our study.

Conclusions

The paradigm of the first-stage PELDID technique combined with the Pola classification system to guide the second-stage treatment for spontaneous spondylodiscitis is a novel and effective strategy for treating spontaneous spondylodiscitis.

C-reactive protein to lymphocyte ratio as a new biomarker in predicting surgical site infection after posterior lumbar interbody fusion and instrumentation

Purpose

This study aims to evaluate the potential of C-reactive protein to lymphocyte count ratio (CLR) for the prediction of surgical site infection (SSI) following posterior lumbar interbody fusion (PLIF) and the instrumentation of lumbar degenerative diseases.

Methods

In this retrospective study, we considered patients with a lumbar degenerative disease diagnosis surgically treated by the instrumented PLIF procedure from 2015 to 2021. Patient data, including postoperative early SSI and other perioperative variables, were collected from their respective hospitalization electronic medical records. The receiver operator characteristic curve was constructed to determine the optimal cut-off value for CLR, and the ability to predict SSI was evaluated by the area under the curve (AUC). According to the cut-off value, patients were dichotomized with high- or low-CLR, and between-group differences were compared using univariate analysis. The independent impact of CLR on predicting SSI was investigated by multivariate logistics regression analysis.

Results

A total of 773 patients were included, with 26 (3.4%) developing an early SSI post-operation. The preoperative CLR was 11.1 ± 26.1 (interquartile range, 0.4–7.5), and the optimal cut-off was 2.1, corresponding to a sensitivity of 0.856, a specificity of 0.643, and an AUC of 0.768 (95% CI, 0.737–0.797). CLR demonstrated a significantly improved prediction ability than did lymphocyte count (P = 0.021) and a similar ability to predict an infection as C-response protein (P = 0.444). Patients with a high CLR had a significantly higher SSI incidence than those with a low CLR (7.6% vs. 0.8%, P < 0.001). After adjustment for numerous confounding factors, CLR ≥ 2.1 was associated with an 11.16-fold increased risk of SSI, along with other significant variables, i.e., diabetes, preoperative waiting time, and surgical duration.

Conclusion

A high CLR exhibited an improved ability to predict incident SSI and was associated with a substantially increased risk of SSI following instrumented PLIF. After better-design studies verified this finding, CLR could potentially be a beneficial tool in surgical management.

A scoping review of complication prediction models in spinal surgery: An analysis of model development, validation and impact

Background

Predictive analytics are being used increasingly in the field of spinal surgery with the development of models to predict post-surgical complications. Predictive models should be valid, generalizable, and clinically useful. The purpose of this review was to identify existing post-surgical complication prediction models for spinal surgery and to determine if these models are being adequately investigated with internal/external validation, model updating and model impact studies.

Methods

This was a scoping review of studies pertaining to models for the prediction of post-surgical complication after spinal surgery published over 10 years (2010-2020). Qualitative data was extracted from the studies to include study classification, adherence to Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) guidelines and risk of bias (ROB) assessment using the Prediction model study Risk Of Bias Assessment Tool (PROBAST). Model evaluation was determined using area under the curve (AUC) when available. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement was used as a basis for the search methodology in four different databases.

Results

Thirty studies were included in the scoping review and 80% (24/30) included model development with or without internal validation. Twenty percent (6/30) were exclusively external validation studies and only one study included an impact analysis in addition to model development and internal validation. Two studies referenced the TRIPOD guidelines and there was a high ROB in 100% of the studies using the PROBAST tool.

Conclusions

The majority of post-surgical complication prediction models in spinal surgery have not undergone standardized model development and internal validation or adequate external validation and impact evaluation. As such there is uncertainty as to their validity, generalizability, and clinical utility. Future efforts should be made to use existing tools to ensure standardization in development and rigorous evaluation of prediction models in spinal surgery.

C-reactive protein to albumin ratio (CAR) in predicting surgical site infection (SSI) following instrumented posterior lumbar interbody fusion (PLIF)

Identification of novel markers would contribute to the individualised risk assessment and development of a risk prediction model. This study aimed to investigate the role of the C-reactive protein to albumin ratio (CAR) in predicting surgical site infection (SSI) following instrumented posterior lumbar interbody fusion (PLIF) of lumbar degenerative diseases. This study enrolled patients who underwent PLIF and instrumentation for treatment of lumbar degenerative diseases between 2015 and 2020. Electronic medical records were inquired for data collection, with follow-up register for identifying SSI cases. The optimal cut-off for CAR was determined by constructing the receiver operator characteristic (ROC) curve. Patients with high- or low-CAR value were compared using the univariate analyses, and the association between CAR and the risk of SSI was investigated using multivariate logistics regression analysis. A total of 905 patients were enrolled, twenty-nine (3.2%) had developed an SSI with 72.4% occurring during index hospitalisation, and 11 (1.2%) had deep and 18 (2.0%) superficial SSIs. An SSI was associated with additional 10.7 days of index total hospital stay (P = .001). The CAR was 0-5.43 (median, 0.05), and the optimal cut-off was 0.09 and area under the curve was 0.720 (P < .001). 336 (37.1%) patients had a CAR ≥0.09 and 22 (6.5%) developed an SSI, with a crude risk of 5.6 relative to those with a low CAR. The multivariate analyses showed CAR ≥0.09 was associated with 8.06-fold increased risk of SSI, together with diabetes (P = .018), while hypertension was identified as a protective factor (OR, 0.34; 95%CI, 0.11-1.00, P = .049). High CAR is found to significantly predict the incident SSI following instrumented PLIF of lumbar degenerative diseases, and can be considered as a useful index in practice only after it is verified by future high-level evidences.

Incidence and risk factors associated with surgical site infection after surgically treated hip fractures in older adults: a retrospective cohort study

BACKGROUND

Surgical site infection (SSI) is one of the most common complications in the traumatic orthopedics field, but remains not adequately studied after hip fractures.

AIMS

This study aims to investigate the incidence and risk factors associated with SSI after surgically treated hip fractures in older adults.

METHODS

A retrospective cohort study including 2932 older adult patients (1416 with femoral neck fracture and 1516 with intertrochanteric fracture) surgically treated from Jan 2015 to Dec 2019 due to hip fractures was performed. Their data on demographics, injury-related data, surgery-related data, and preoperative laboratory test results were collected from hospitalization medical records. Univariate analyses were used to compare between the patients with and without SSI, and multivariate logistic regression analyses were used to identify the risk factors.

RESULTS

A total of 89 patients developed SSI, with an accumulated incidence rate of 3.04% (95%CI 2.41-3.66). Staphylococcus aureus was the most common source of infection. In univariate analysis, 11 items were found to be significant in femoral neck fractures and 5 items were found to be significant in intertrochanteric fracture. In the multivariable logistic regression model, cerebrovascular disease (OR 2.17, 95%CI 1.14-4.15) and hematocrit (HCT) (< Lower limit) (OR 3.46, 95%CI 1.13-10.56) were independent risk factors for SSI in femoral neck fracture. Heart disease (OR 2.13, 95%CI 1.18-3.85) was a risk factor for SSI, while LDH (> 250 U/L) (OR 0.44, 95%CI 0.20-0.95) was a protective factor for SSI in intertrochanteric fracture.

DISCUSSION

We observed 89 cases (3.04%) of SSI in 2932 older adult patients with hip fractures in this study. Cerebrovascular disease and lower HCT were two independent risk factors for SSI in femoral neck fracture, whereas heart disease was a risk factor and LDH was a protective factor for SSI in intertrochanteric fracture.

CONCLUSIONS

Targeted preoperative management, such as predicting the probability of SSI and taking appropriate measures accordingly is essential and highly regarded. Future multicentric studies with more patients evaluated are expected to better address the risk factors for SSI in older hip fracture patients.

Development and Internal Validation of Supervised Machine Learning Algorithms for Predicting the Risk of Surgical Site Infection Following Minimally Invasive Transforaminal Lumbar Interbody Fusion

Purpose: Machine Learning (ML) is rapidly growing in capability and is increasingly applied to model outcomes and complications in medicine. Surgical site infections (SSI) are a common post-operative complication in spinal surgery. This study aimed to develop and validate supervised ML algorithms for predicting the risk of SSI following minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF).

Methods: This single-central retrospective study included a total of 705 cases between May 2012 and October 2019. Data of patients who underwent MIS-TLIF was extracted by the electronic medical record system. The patient's clinical characteristics, surgery-related parameters, and routine laboratory tests were collected. Stepwise logistic regression analyses were used to screen and identify potential predictors for SSI. Then, these factors were imported into six ML algorithms, including k-Nearest Neighbor (KNN), Decision Tree (DT), Support Vector Machine (SVM), Random Forest (RF), Multi-Layer Perceptron (MLP), and Naïve Bayes (NB), to develop a prediction model for predicting the risk of SSI following MIS-TLIF under Quadrant channel. During the training process, 10-fold cross-validation was used for validation. Indices like the area under the receiver operating characteristic (AUC), sensitivity, specificity, and accuracy (ACC) were reported to test the performance of ML models.

Results: Among the 705 patients, SSI occurred in 33 patients (4.68%). The stepwise logistic regression analyses showed that pre-operative glycated hemoglobin A1c (HbA1c), estimated blood loss (EBL), pre-operative albumin, body mass index (BMI), and age were potential predictors of SSI. In predicting SSI, six ML models posted an average AUC of 0.60–0.80 and an ACC of 0.80–0.95, with the NB model standing out, registering an average AUC and an ACC of 0.78 and 0.90. Then, the feature importance of the NB model was reported.

Conclusions: ML algorithms are impressive tools in clinical decision-making, which can achieve satisfactory prediction of SSI with the NB model performing the best. The NB model may help access the risk of SSI following MIS-TLIF and facilitate clinical decision-making. However, future external validation is needed.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines for Perioperative Spine: Preoperative Surgical Risk Assessment

BACKGROUND

Patient factors (increased body mass index [BMI], smoking, and diabetes) may impact outcomes after spine surgery. There is a lack of consensus regarding which factors should be screened for and potentially modified preoperatively to optimize outcome.

OBJECTIVE

The purpose of this evidence-based clinical practice guideline is to determine if preoperative patient factors of diabetes, smoking, and increased BMI impact surgical outcomes.

METHODS

A systematic review of the literature for studies relevant to spine surgery was performed using the National Library of Medicine PubMed database and the Cochrane Library. Clinical studies evaluating the impact of diabetes or increased BMI with reoperation and/or surgical site infection (SSI) were selected for review. In addition, the impact of preoperative smoking on patients undergoing spinal fusion was reviewed.

RESULTS

A total of 699 articles met inclusion criteria and 64 were included in the systematic review. In patients with diabetes, a preoperative hemoglobin A1c (HbA1c) >7.5 mg/dL is associated with an increased risk of reoperation or infection after spine surgery. The review noted conflicting studies regarding the relationship between increased BMI and SSI or reoperation. Preoperative smoking is associated with increased risk of reoperation (Grade B). There is insufficient evidence that cessation of smoking before spine surgery decreases the risk of reoperation.

CONCLUSION

This evidence-based guideline provides a Grade B recommendation that diabetic individuals undergoing spine surgery should have a preoperative HbA1c test before surgery and should be counseled regarding the increased risk of reoperation or infection if the level is >7.5 mg/dL. There is conflicting evidence that BMI correlates with greater SSI rate or reoperation rate (Grade I). Smoking is associated with increased risk of reoperation (Grade B) in patients undergoing spinal fusion.The full guidelines can be accessed at https://www.cns.org/guidelines/browse-guidelines-detail/2-preoperative-surgical-risk-assessement.

Incidences and reasons of postoperative surgical site infection after lumbar spinal surgery: a large population study

PURPOSE

The purpose of this study was to determine the incidences of postoperative acute surgical site infection (SSI) after lumbar spinal surgery and its possible reasons in our hospital during the past 9 years.

METHODS

This is a retrospective study with a large sample size. The medical records of all included patients were reviewed, and patients with acute SSI were identified. The incidence and possible reasons of SSI were determined.

RESULTS

A total of 7240 patients who underwent posterior lumbar spinal surgery were included in this study, and the total incidence of postoperative SSI was 1.53% (111/7240). Gram-negative bacteria were found to be dominant in postoperative wound infections after lumbar spinal surgery. And Escherichia coli were the most common pathogen in patients with SSI. The rate of postoperative SSI following lumbar spinal surgery was increased at first and then decreased during the past 9 years. Additionally, from 2011 to 2014, it was mainly deep infection in these patients, and then was mainly superficial infection from 2015 to 2019. Patients with lumbar spinal stenosis had the highest incidence of postoperative SSI (2.39%, P < 0.001). There was also a significant difference for the number of SSI cases among different surgeons.

CONCLUSION

Based on a large population analysis, Gram-negative bacteria were the most common pathogen in postoperative SSI after lumbar spinal surgery. And patients with lumbar spinal stenosis had the highest incidence of SSI. Increasing the intervention of Gram-negative may be an important step to reduce the postoperative SSI after lumbar spinal surgery.

Perioperative antibiotic prophylaxis in spinal surgery

Study design: Complete audit cycle. Introduction: To highlight the unjustified overuse of perioperative antibiotics in clean non-instrumented lumbar spinal surgeries. To convince orthopedic surgeons in a methodological way of local field comparison between common practice on the use of perioperative antibiotics prophylaxis (PAP) in clean non-instrumented lumbar spinal surgeries and the ideal practice according to “The guidelines published by North American Spine Society (NASS)”. Methods: A complete audit cycle had been done. One hundred and eight patients underwent clean non-instrumented lumbar spinal surgeries in a tertiary spine center, during the period from the 1st of April to the 31st of June 2017 (primary audit period) and during the period from the 8th of May to the 21st of November 2018 (re-audit period). Group I: audit group (n = 54) was given the usual regimen (IV first-generation cephalosporin for 1–6 days, followed by oral antibiotics, till the removal of stitches) and Group II: re-audit group (n = 54) received only the IV antibiotics for one day). The study protocol was approved by our institution’s Ethical Committee (17100582). Results: This study showed a wide gap between international standards and local prescribing practices and calls for multiple interventions to improve our practice. Out of the 108 patients, only one case (1.85%) developed surgical site infection (SSI) in the audit group (Group I). The difference in infection rates between the two groups was statistically insignificant. Conclusion: A single-day postoperative dose of antibiotics effectively prevents postoperative wound infection following non-instrumented lumbar spinal surgery and is not associated with a higher infection rate.

Lumbar Intervertebral Spacer With Cement Augmentation of Endplates and Integrated Screws as a Fixation Device in an Osteoporotic Model: An In Vitro Kinematic and Load-to-Failure Study

BACKGROUND

Integrated lateral lumbar interbody fusion (LLIF) devices have been shown to successfully stabilize the spine and avoid complications related to posterior fixation. However, LLIF has increased subsidence risk in osteoporotic patients. Cement augmentation through cannulated pedicle screws enhances pedicle fixation and cage-endplate interface yet involves a posterior approach. Lateral application of cement with integrated LLIF fixation has been introduced and requires characterization. The present study set out to evaluate kinematic and load-to-failure properties of a novel cement augmentation technique with an integrated LLIF device, alone and with unilateral pedicle fixation, compared with bilateral pedicle screws and nonintegrated LLIF (BPS + S).

METHODS

Twelve specimens (L3-S1) underwent discectomy at L4-L5. Specimens were separated into 3 groups: (1) BPS + S; (2) polymethyl methacrylate (PMMA) augmentation, integrated LLIF, and unilateral pedicle screws (PMMA + UPS + iS); and (3) PMMA and integrated LLIF (PMMA + iSA) without posterior fixation. Flexion-extension, lateral bending, and axial rotation were applied. A compressive load was applied to L4-L5 segments until failure. An analysis was performed (P < .05).

RESULTS

Operative constructs significantly reduced motion relative to intact specimens in all motion planes (P < .05). BPS + S provided the most stability, reducing motion by 71.6%-86.4%, followed by PMMA + UPS + iS (68.1%-79.4%) and PMMA + iSA (62.9%-81.9%); no significant differences were found (P > .05). PMMA + UPS + iS provided the greatest resistance to failure (2290 N), followed by PMMA + iSA (1970 N) and BPS + S (1390 N); no significant differences were observed (P > .05).

CONCLUSIONS

Cement augmentation of vertebral endplates via the lateral approach with integrated LLIF moderately improved cage-endplate strength compared to BPS + S in an osteoporotic model; unilateral pedicle fixation further improved failure load. Reconstruction before and after application of unilateral pedicle screws and rods was biomechanically equivalent to anteroposterior reconstruction. Overall, initial results suggest that integrated LLIF with cement augmentation may be a viable alternative in the presence of osteoporosis.

Do Preoperative Epidural Steroid Injections Increase the Risk of Infection After Lumbar Spine Surgery?

STUDY DESIGN

Retrospective study.

OBJECTIVE

To elucidate an association between preoperative lumbar epidural corticosteroid injections (ESI) and infection after lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

ESI may provide diagnostic and therapeutic benefit; however, concern exists regarding whether preoperative ESI may increase risk of postoperative infection.

METHODS

Patients who underwent lumbar decompression alone or fusion procedures for radiculopathy or stenosis between 2000 and 2017 with 90 days follow-up were identified by ICD/CPT codes. Each cohort was categorized as no preoperative ESI, less than 30 days, 30 to 90 days, and greater than 90 days before surgery. The primary outcome measure was postoperative infection requiring reoperation within 90 days of index procedure. Demographic information including age, sex, body mass index (BMI), Charlson Comorbidity Index (CCI) was determined. Comparison and regression analysis was performed to determine an association between preoperative ESI exposure, demographics/comorbidities, and postoperative infection.

RESULTS

A total of 15,011 patients were included, 5108 underwent fusion and 9903 decompression only. The infection rate was 1.95% and 0.98%, among fusion and decompression patients, respectively. There was no association between infection and preoperative ESI exposure at any time point (1.0%, P = 0.853), ESI within 30 days (1.37%, P = 0.367), ESI within 30 to 90 days (0.63%, P = 0.257), or ESI > 90 days (1.3%, P = 0.277) before decompression surgery. There was increased risk of infection in those patients undergoing preoperative ESI before fusion compared to those without (2.68% vs. 1.69%, P = 0.025). There was also increased risk of infection with an ESI within 30 days of surgery (5.74%, P = 0.005) and when given > 90 days (2.9%, P = 0.022) before surgery. Regression analysis of all patients demonstrated that fusion (P < 0.001), BMI (P < 0.001), and CCI (P = 0.019) were independent predictors of postoperative infection, while age, sex, and preoperative ESI exposure were not.

CONCLUSION

An increased risk of infection was found in patients with preoperative ESI undergoing fusion procedures, but no increased risk with decompression only. Fusion, BMI, and CCI were predictors of postoperative infection.Level of Evidence: 3.

Can natural language processing provide accurate, automated reporting of wound infection requiring reoperation after lumbar discectomy?

BACKGROUND

Surgical site infections are a major driver of morbidity and increased costs in the postoperative period after spine surgery. Current tools for surveillance of these adverse events rely on prospective clinical tracking, manual retrospective chart review, or administrative procedural and diagnosis codes.

PURPOSE

The purpose of this study was to develop natural language processing (NLP) algorithms for automated reporting of postoperative wound infection requiring reoperation after lumbar discectomy.

PATIENT SAMPLE

Adult patients undergoing discectomy at two academic and three community medical centers between January 1, 2000 and July 31, 2019 for lumbar disc herniation.

OUTCOME MEASURES

Reoperation for wound infection within 90 days after surgery METHODS: Free-text notes of patients who underwent surgery from January 1, 2000 to December 31, 2015 were used for algorithm training. Free-text notes of patients who underwent surgery after January 1, 2016 were used for algorithm testing. Manual chart review was used to label which patients had reoperation for wound infection. An extreme gradient-boosting NLP algorithm was developed to detect reoperation for postoperative wound infection.

RESULTS

Overall, 5,860 patients were included in this study and 62 (1.1%) had a reoperation for wound infection. In patients who underwent surgery after January 1, 2016 (n=1,377), the NLP algorithm detected 15 of the 16 patients (sensitivity=0.94) who had reoperation for infection. In comparison, current procedural terminology and international classification of disease codes detected 12 of these 16 patients (sensitivity=0.75). At a threshold of 0.05, the NLP algorithm had positive predictive value of 0.83 and F1-score of 0.88.

CONCLUSION

Temporal validation of the algorithm developed in this study demonstrates a proof-of-concept application of NLP for automated reporting of adverse events after spine surgery. Adapting this methodology for other procedures and outcomes in spine and orthopedics has the potential to dramatically improve and automatize quality and safety reporting.

Evaluation of Predictive Models for Complications following Spinal Surgery

BACKGROUND

 Complications rates vary across spinal surgery procedures and are difficult to predict due to heterogeneity in patient characteristics, surgical methods, and hospital volume. Incorporation of predictive models for complications may guide surgeon decision making and improve outcomes.

METHODS

 We evaluate current independently validated predictive models for complications in spinal surgery with respect to study design and model generation, accuracy, reliability, and utility. We conducted our search using Preferred Reporting Items for Systematic Review and Meta-analysis guidelines and the Participants, Intervention, Comparison, Outcomes, Study Design model through the PubMed and Ovid Medline databases.

RESULTS

 A total of 18 articles met inclusion criteria including 30 validated predictive models of complications after adult spinal surgery. National registry databases were used in 12 studies. Validation cohorts were used in seven studies for verification; three studies used other methods including random sample bootstrapping techniques or cross-validation. Reported area under the curve (AUC) values ranged from 0.37 to 1.0. Studies described treatment for deformity, degenerative conditions, inclusive spinal surgery (neoplasm, trauma, infection, deformity, degenerative), and miscellaneous (disk herniation, spinal epidural abscess). The most commonly cited risk factors for complications included in predictive models included age, body mass index, diabetes, sex, and smoking. Those models in the deformity subset that included radiographic and anatomical grading features reported higher AUC values than those that included patient demographics or medical comorbidities alone.

CONCLUSIONS

 We identified a cohort of 30 validated predictive models of complications following spinal surgery for degenerative conditions, deformity, infection, and trauma. Accurate evidence-based predictive models may enhance shared decision making, improve rehabilitation, reduce adverse events, and inform best practices.

Clinical and radiological outcomes between biportal endoscopic decompression and microscopic decompression in lumbar spinal stenosis

BACKGROUND CONTEXT

Numerous minimal invasive techniques treating lumbar spinal stenosis have been introduced. Clinical results using biportal endoscopic spinal surgery has recently been introduced as a treatment option for lumbar spinal stenosis. The purpose of this study was to compare the clinical and radiologic outcome between microscopic unilateral laminotomy bilateral decompression and biportal endoscopic unilateral laminotomy bilateral decompression in patients with degenerative lumbar spinal stenosis.

METHOD

A total of 89 patients were evaluated for this study. Only single-level patients were enrolled for accurate comparison. Patients that underwent biportal endoscopic surgery were assigned to Group A, and patients that underwent microscopic surgery were designated Group B. Clinical outcomes were evaluated using modified Macnab criteria, Oswestry Disability Index, and Visual Analog Scale. Postoperative complications were checked until final follow up. Plain radiographs before and after surgery were compared to analyze the change of alignment.

RESULT

There was a significant difference between Group A and B in VAS of back on postoperative 2 months. Other clinical measurements except for postoperative 2 months VAS of back showed no significant difference. There were no significant differences between Group A and Group B regarding preoperative and postoperative radiological findings.

CONCLUSION

Two different decompression techniques preserve the spinal structure and exhibit a favorable clinical outcome and have the advantage of not causing postoperative instability in the short term follow up. Biportal endoscopic surgery may leads to less postoperative back pain than microscopic surgery, which may allow early ambulation and shorter hospitalization period.

Global Treatment Outcome after Surgical Site Infection in Elective Degenerative Lumbar Spinal Operations

Background: Surgical site infection (SSI) is a serious complication after routine lumbar spinal operations, and its effect on global treatment outcome (GTO) is less reported. The aim of the current study was to measure the impact of SSI on outcome, which was evaluated with patient reported outcome measures (PROMs) and patients' subjective judgment (GTO). Methods: A total of 910 patients underwent primary a single- or two-level lumbar decompression or instrumented fusion surgical procedure. Patients completed Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), and Core Outcome Measurement Index (COMI) at baseline and at two-year follow-up. The rate of improvement in PROMs was measured for the total cohort and the group of patients with SSI. Patients evaluated GTO on a five-point Likert scale. This study was approved by the Scientific and Research Ethics Committee of the Medical Research Council (number: 29970-3/2015/EKU) and the Institutional Review Board. Results: Regardless of the presence of SSI, significant improvement was measured in all PROMs without any difference in the rate of change between the clinical subgroups (non-SSI vs. SSI, dODI: p = 0.370, dCOMI: p = 0.383, dVAS: p = 0.793). In the total cohort, 87.3% of patients reported good outcome (N% = 87.3%). After an SSI, however, more patients (25.7%) reported poor outcome compared with those without the complication (chi-square test: value = 5.66; df = 1; p = 0.017; odds ratio = 2.49). Conclusions: Patients with successfully treated SSI can expect as good objective clinical result as patients without SSI while the subjective treatment outcome can be worse. The GTO could also be improved in complicated cases, however, with more extensive peri-operative patient education and information considering the patients' expectations, too.

Current Strategies in Prevention of Postoperative Infections in Spine Surgery

STUDY DESIGN

Narrative review.

OBJECTIVES

Postoperative surgical site infections (SSIs) are among the most common acute complications in spine surgery and have a devastating impact on outcomes. They can lead to increased morbidity and mortality as well as greater economic burden. Hence, preventive strategies to reduce the rate of SSIs after spine surgery have become vitally important. The purpose of this article was to summarize and critically analyze the available evidence related to current strategies in the prevention of SSIs after spine surgery.

METHODS

A literature search utilizing Medline database was performed. Relevant studies from all the evidence levels have been included. Recommendations to decrease the risk of SSIs have been provided based on the results from studies with the highest level of evidence.

RESULTS

SSI prevention occurs at each phase of care including the preoperative, intraoperative, and postoperative periods. Meticulous patient selection, tight glycemic control in diabetics, smoking cessation, and screening/eradication of Staphylococcus aureus are some of the main preoperative patient-related preventive strategies. Currently used intraoperative measures include alcohol-based skin preparation, topical vancomycin powder, and betadine irrigation of the surgical site before closure. Postoperative infection prophylaxis can be performed by administration of silver-impregnated or vacuum dressings, extended intravenous antibiotics, and supplemental oxygen therapy.

CONCLUSIONS

Although preventive strategies are already in use alone or in combination, further high-level research is required to prove their efficacy in reducing the rate of SSIs in spine surgery before evidence-based standard infection prophylaxis guidelines can be built.

Use of Intraoperative Tranexamic Acid and Wound Complications in Spine Surgery: A Retrospective Cohort Study

Study Design

A retrospective cohort study.

Purpose

This study aims to examine the effect of tranexamic acid (TXA) on postoperative wound healing in spine surgery.

Overview of Literature

TXA (Cyklokapron, Hexakapron) is a widely used anti-fibrinolytic drug that is shown to be effective in mitigating hemorrhage during and after surgery by competitively blocking plasminogen in fibrinolytic cascade. Plasminogen also plays a role in inflammatory and infectious diseases. The modulation of this role by TXA may influence the development of postoperative infectious complications.

Methods

We collected and reviewed the charts of 110 patients who underwent spine surgery at our academic center. We used multivariate regression analysis to assess the factors affecting surgical site infection (SSI).

Results

Of the 110 patients included in this study, 21 patients (19%) were categorized as having postoperative wound complications, 16 patients (14%) had deep or superficial wound infection, and five patients (4%) had wound dehiscence. Patients with a higher surgical invasiveness index score, longer surgeries, and older patients were found to be at risk for wound complications. TXA was determined not to be a direct risk factor for wound healing complications and SSIs.

Conclusions

We found no risk of wound healing complications and SSI directly attributable to preoperative and intraoperative treatment with TXA in spine surgeries.

Comparative outcomes of operative relative to medical management of spondylodiscitis accounting for frailty status at presentation

PURPOSE

Investigate outcomes in a spondylodiscitis (SD) patient cohort undergoing operative and medical treatment or medical treatment alone, accounting for frailty status at presentation.

METHODS

Patients >18 years old undergoing treatment for SD were retrospectively analyzed. The diagnosis of SD was made through a combination of clinical findings, MRI/CT findings, and blood/tissue cultures. Those who failed to respond to antibiotics, had deteriorating markers, or developed neurologic compromise were considered operative candidates. Patients were stratified based on operative (Op, operative plus medical management) or conservative (Cons, medical only) treatment. Univariate analyses identified differences in outcome measures across treatment groups. Conditional forward regression equations, controlling for patient age, identified predictors of increased mortality and inferior outcomes.

RESULTS

116 patients with SD were included. 73 underwent Cons treatment and 43 were Op. Op patients were significantly younger (62.9vs70.7yrs; p < 0.001) and less frail (1.09vs1.85; p < 0.006) than Cons patients, with significantly higher WCC and ESR. Cons pts had higher rates of isolated SD, but Op pts had higher rates of SD with associated SEA, VOM, psoas abscess, and para-vertebral abscess (all p < 0.05). Op pts had significantly lower 30-day mortality than Cons pts (2.3%vs17.8%, p = 0.016), and trended lower 1Y mortality (11.6%vs20.5%, p = 0.310) with similar SD recurrence rates (11.6%vs16.4%, p = 0.592). Patients with an mFI > 3 had significantly higher 30-day mortality (30.4% vs 7.5%, p = 0.003) and trended higher 1-year mortality regardless of intervention.

CONCLUSIONS

Operative intervention was associated with lower 30-day mortality significantly and 1-year mortality compared to conservative treatment, while an increased mFI was associated with higher short-term mortality.

Evaluation and Treatment of Tandem Spinal Stenosis

Tandem spinal stenosis (TSS) refers to simultaneous narrowing of noncontiguous regions of the spinal canal, typically the cervical and lumbar region. Symptomatic TSS may be present in more than 10% of patients presenting with spinal symptoms secondary to stenosis in any one region. Clinical presentation may present challenges because of a mixture of upper and lower motor neuron lesions that can confuse and mislead the clinician. Stenosis at another level may only be detected late, when there is failure to improve after treatment, and, if not detected, can result in either poor treatment outcomes or catastrophic complications. There is no uniform agreement in the management of TSS, and the reported surgical strategies include both simultaneous and staged approaches with each having positive and negative features. This article aims to provide the reader with details on the prevalence, evaluation, and guidance in treatment strategy for TSS.

Red flags for the early detection of spinal infection in back pain patients

BACKGROUND

Red flags are signs and symptoms that are possible indicators of serious spinal pathology. There is limited evidence or guidance on how red flags should be used in practice. Due to the lack of robust evidence for many red flags their use has been questioned. The aim was to conduct a systematic review specifically reporting on studies that evaluated the diagnostic accuracy of red flags for Spinal Infection in patients with low back pain.

METHODS

Searches were carried out to identify the literature from inception to March 2019. The databases searched were Medline, CINHAL Plus, Web of Science, Embase, Cochrane, Pedro, OpenGrey and Grey Literature Report. Two reviewers screened article texts, one reviewer extracted data and details of each study, a second reviewer independently checked a random sample of the data extracted.

RESULTS

Forty papers met the eligibility criteria. A total of 2224 cases of spinal infection were identified, of which 1385 (62%) were men and 773 (38%) were women mean age of 55 (± 8) years. In total there were 46 items, 23 determinants and 23 clinical features. Spinal pain (72%) and fever (55%) were the most common clinical features, Diabetes (18%) and IV drug use (9%) were the most occurring determinants. MRI was the most used radiological test and Staphylococcus aureus (27%), Mycobacterium tuberculosis (12%) were the most common microorganisms detected in cases.

CONCLUSION

The current evidence surrounding red flags for spinal infection remains small, it was not possible to assess the diagnostic accuracy of red flags for spinal infection, as such, a descriptive review reporting the characteristics of those presenting with spinal infection was carried out. In our review, spinal infection was common in those who had conditions associated with immunosuppression. Additionally, the most frequently reported clinical feature was the classic triad of spinal pain, fever and neurological dysfunction. This is an Open Access article distributed in accordance with the Creative Commons Attribution Non-Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

The effect of lumbar corticosteroid injections on postoperative infection in lumbar arthrodesis surgery

We sought to characterize the association between lumbar corticosteroid injections and postoperative infection rate for patients in the Military Health System undergoing lumbar arthrodesis. The Military Health System Data Repository was searched for all patients undergoing lumbar arthrodesis from 2009 to 2014. Current Procedural Terminology (CPT) codes were used to identify the subset of patients who also received preoperative lumbar corticosteroid injections. These patients were stratified by timing, type, and number of injections. Infection rates were compared to the control group of patients who did not receive preoperative lumbar corticosteroid injections. The search identified 3403 patients who had undergone lumbar arthrodesis from 2009 to 2014 within the Military Health System. 612 patients had received lumbar corticosteroid injections prior to surgery (348 epidural, 264 facet). The control group consisted of the remaining 2791 patients. Overall post-operative infection rate was 1.47% with an infection rate in the injection group of 1.14% versus 1.54% in the control group. When stratified by time, infection rates ranged from 0% to 1.85% in the injection groups. No differences between injection and control groups reached statistical significance in any subgroup analysis. Post-operative infection rate is not significantly increased in patients receiving lumbar corticosteroid injections (LCSIs) prior to lumbar arthrodesis. No differences were observed in infection rates based on timing, type, or number of injections prior to surgery.

Effects of Operating Room Size on Surgical Site Infection Following Lumbar Fusion Surgery

Background

Surgical site infections (SSIs) represent a devastating complication after spine surgery. Many factors have been identified, but the influence of operating room (OR) size on infection rate has not been assessed.

Methods

Two thousand five hundred and twenty-three patients who underwent open lumbar spine fusion at a single institution between 2010 and 2016 were included. Patients were dichotomized into large versus small groups based on OR volume. Bivariate logistic regression and a final multivariate model following a multicollinearity check were used to calculate odds of infection for all variables.

Results

A total of 63 patients (2.5%) developed SSIs with 46 (73%) in the larger OR group and 17 (27%) in the smaller OR group. The rate of SSIs in larger ORs was 3.02% compared with 1.81% in smaller ORs. Significant parameters impacting SSI in bivariate analysis included an earlier year of surgery, BMI > 30, more comorbidities, more levels decompressed and fused, smoking, and larger OR volumes. Multivariate analysis identified BMI > 30, Elixhauser scores, smoking, and increasing levels decompressed as significant predictors. Topical vancomycin was found to significantly decrease rate of infection in both analyses.

Conclusions

OR size (large versus small) was ultimately not a significant predictor of infection related to rates of SSIs, although it did show a clinical trend toward significance, suggesting association. Future prospective analysis is warranted.

Level of Evidence

3.

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

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.

Treatment of Isolated Serosanguinous Incision Drainage after Thoracolumbar Surgery: Is Surgical Management Always Necessary?

Background: There is no consensus regarding how to care for a patient presenting with early isolated incision drainage after thoracolumbar spine surgery. Although drainage is the most common presenting symptom of surgical site infection (SSI), it has low specificity for SSI in the absence of other symptoms. Given that invasive treatment for SSI is costly and high risk, it would be beneficial to determine whether antibiotic treatment alone is sufficient for isolated drainage and what factors predispose to failure of this conservative strategy. Methods: The authors retrospectively reviewed a clinical database of patients who underwent thoracolumbar spine surgery at a single center between 2012-2017. Patients were included if serosanguinous drainage was present within six weeks of surgery without other signs and symptoms of infection such as fever, chills, purulent discharge, fluctuance, wound dehiscence, or erythema. Results: Fifty-eight patients met the study inclusion criteria. After initial conservative management with antibiotics, drainage resolved in 51 patients. The seven patients with drainage that did not resolve were treated with operative surgical washout. Although the groups were similar in most respects, there was a significant difference in the American Society of Anesthesiologists (ASA) score, which is a marker of overall health (surgical group score 2.89 ± 0.33 versus 2.06 ± 0.61; p < 0.0001). In addition, patients with greater estimated blood loss, length of hospital stay, operative time, and spinal levels treated were more likely to require surgical washout, although these differences were not statistically significant. Groups were similar with respect to age, Body Mass Index, smoking status, diabetes mellitus status, revision versus primary surgery, and drainage latency. Conclusion: Most patients who present with isolated serosanguinous incision drainage within six weeks of surgery may be managed successfully using antibiotics only. Patients who fail to respond to conservative therapy have significantly worse general health, as indicated by the ASA score.

[Rheumatoid instability in the cervical spine : Diagnostic and therapeutic strategies]

BACKGROUND

The involvement of the cervical spine in rheumatoid arthritis (RA) continues to be of clinical importance even in this age of biologics. Pathophysiological changes begin with an isolated atlantoaxial subluxation and may progress to a complex craniocervical and subaxial instability. The onset of cervical myelopathy can occur at any time and leads to a deterioration of the prognosis for the patient.

THERAPY

Treatment of the rheumatoid cervical spine should be aimed at improvement of the symptoms and prevention of further progress of the disease. In the case of instability, this is only possible by surgical treatment. The increasing usage of biological agents has led to a change in the clinical picture of the cervical involvement in RA patients. There are fewer patients presenting with isolated atlantoaxial instability. In contrast, the number of patients with complex craniocervical and/or subaxial instabilities is increasing. Complex cervical instabilities may require a longer fusion from the occiput to the upper thoracic spine. Modern operative techniques make this complex surgery also possible in severely disabled patients with a high comorbidity.

Surgical site infection following elective orthopaedic surgeries in geriatric patients: Incidence and associated risk factors

The purposes of this study were to investigate the incidence of surgical site infection (SSI) following geriatric elective orthopaedic surgeries and identify the associated risk factors This was a retrospective two-institution study. Between January 2014 and September 2017, patients aged 60 years or older undergoing elective orthopaedic surgeries were included for data collection and analysis. SSI was identified through the review of patients' medical records for the index surgery and through the readmission diagnosis of SSI. Patients' demographics, characteristics of disease, surgery-related variables, and laboratory examination indexes were inquired and documented. Univariate and multivariate logistic analyses were performed to determine independent risk factors for SSI. There were 4818 patients undergoing elective orthopaedic surgeries, and within postoperative 1 year, 74 patients were identified to develop SSIs; therefore, the overall incidence of SSI was 3.64%, with 0.4% for deep and 1.1% for superficial infection. Staphylococcus aureus (25/47, 53.2%) and coagulase-negative staphylococci (11/47, 23.4%) were the most common causative pathogens; half of S. aureus SSIs were caused by Methicillin-resistant Staphylococcus aureus (MRSA) (12/25, 48.0%). Five risk factors were identified to be independently associated with SSI, including diabetes mellitus (odds ratio [OR], 3.7; 95% confidence interval [95% CI], 1.7-5.6), morbid obesity (OR, 2.6; 95% CI, 1.3-3.9), tobacco smoking (OR, 4.2; 95% CI, 2.1-6.4), surgical duration>75th percentile (OR, 1.9; 95% CI, 1.0-2.9), and ALB < 35.0 g/L (OR, 2.3; 95% CI, 1.3-3.4). We recommend the optimisation of modifiable risk factors such as morbid obesity, tobacco smoking, and lower serum albumin level prior to surgeries to reduce the risk of SSI.

Comparison of pyogenic postoperative and native vertebral osteomyelitis

BACKGROUND CONTEXT

Postoperative vertebral osteomyelitis (PVO) after spinal surgery is a clinical challenge. However, there is a paucity of evidence regarding the most likely etiologic organisms to guide the choice of empirical antibiotic therapy, and previous reports of treatment outcomes for PVO are scarce.

PURPOSE

To compare the microbiology, clinical characteristics, and outcomes of pyogenic PVO with native vertebral osteomyelitis (NVO).

STUDY DESIGN

Retrospective comparative study.

PATIENT SAMPLE

Patients with microbiologically proven vertebral osteomyelitis from three university-affiliated hospitals in South Korea between January 2005 and December 2015 with follow-up of at least 12 months after completion of antibiotics or until the patient was transferred. Patients who had a spine operation in the same location within 1 year of diagnosis, and all patients with remnant implants at the time of the vertebral osteomyelitis diagnosis, were defined as having PVO. The remainder of the patients was considered to have NVO. Spinal operations included discectomy, laminectomy, arthrodesis, and instrumentation for stabilization of the spine.

OUTCOME MEASURES

Overall mortality, neurologic outcomes, treatment failure, and relapse of infection.

METHODS

Demographic data, comorbidities, presenting symptoms, microbiological data, radiographic characteristics, laboratory data (including white blood cell counts, erythrocyte sedimentation rate, and C-reactive protein), surgical treatment, and neurologic outcomes for each patient were reviewed from electronic medical records and analyzed. Mortality rate, treatment failure, and relapse of infection were calculated for the two groups. Factors associated with treatment outcome were evaluated using univariate and multivariate logistic regression analyses.

RESULTS

The study evaluated 104 patients with PVO and 441 patients with NVO. In PVO, the most common isolate was Staphylococcus aureus (34%, n=35), followed by coagulase-negative staphylococci (31%, n=32). In NVO, the most common isolates were S. aureus (47%, n=206) and streptococci (21%, n=94). Of the staphylococci, the proportion of methicillin-resistant strains was significantly higher in PVO than that in NVO (75% vs. 39%, p<.001). The proportion of patients with gram-negative bacilli was 14% in PVO and 20% in NVO. Pre-existing or synchronous nonspinal infection was observed more frequently in NVO than in PVO (33% vs. 13%, p<.001). Although the duration of antibiotic use was similar in both groups, surgery for infection control was performed more frequently in PVO. The mortality rate was similar in both groups. However, the treatment failure and relapse rates at 12 months were higher in the PVO group (23% vs. 13%, p=.009; 14% vs. 7%, p=.028, respectively). Methicillin-resistant S.aureus was significantly associated with treatment failure or relapse via logistic regression (odds ratio 3.01, 95% confidence interval [1.71-5.32], p<.001; odds ratio 2.78, 95% confidence interval [1.40-5.49], p=.003).

CONCLUSIONS

Coverage of methicillin-resistant staphylococci should be considered when prescribing empirical antibiotics for PVO. Although surgery was performed more often in PVO than NVO, the treatment failure and relapse rates at 12 months were higher in PVO.

Risk of Surgical Site Infection and Mortality Following Lumbar Fusion Surgery in Patients With Chronic Steroid Usage and Chronic Methicillin-Resistant Staphylococcus aureus Infection

STUDY DESIGN

A retrospective database analysis among Medicare beneficiaries OBJECTIVE.: The aim of this study was to determine the effect of chronic steroid use and chronic methicillin-resistant Staphylococcus aureus (MRSA) infection on rates of surgical site infection (SSI) and mortality in patients 65 years of age and older who were treated with lumbar spine fusion.

SUMMARY OF BACKGROUND DATA

Systemic immunosuppression and infection focus elsewhere in the body are considered risk factors for SSI. Chronic steroid use and previous MRSA infection have been associated with an increased risk of SSI in some surgical procedures, but their impact on the risk of infection and mortality after lumbar fusion surgery has not been studied in detail.

METHODS

The PearlDiver insurance-based database (2005-2012) was queried to identify 360,005 patients over 65 years of age who had undergone lumbar spine fusion. Of these patients, those who had been taking oral glucocorticoids chronically and those with a history of chronic MRSA infection were identified. The rates of SSI and mortality in these two cohorts were compared with an age- and risk-factor matched control cohort and odds ratio (OR) was calculated.

RESULTS

Chronic oral steroid use was associated with a significantly increased risk of 1-year mortality [OR = 2.06, 95% confidence interval (95% CI) 1.13-3.78, P = 0.018] and significantly increased risk of SSI at 90 days (OR = 1.74, 95% CI 1.33-1.92, P < 0.001) and 1 year (OR = 1.88, 95% CI 1.41-2.01, P < 0.001). Chronic MRSA infection was associated with a significantly increased risk of SSI at 90 days (OR = 6.99, 95% CI 5.61-9.91, P < 0.001) and 1 year (OR = 24.0, 95%CI 22.20-28.46, P < 0.001) but did not significantly impact mortality.

CONCLUSION

Patients over 65 years of age who are on chronic oral steroids or have a history of chronic MRSA infection are at a significantly increased risk of SSI following lumbar spine fusion.

LEVEL OF EVIDENCE

3.

Prognosis of deep infection in spinal surgery using implants, treated by retention, removal of bone graft and lengthy antibiotherapy

OBJECTIVE

Surgical site infections (SSIs) are complications that predispose to a high risk of unfavourable surgical outcomes. The aim of this study was to assess the SSI rate in this type of patients and their prognosis with similar treatment.

MATERIALS AND METHODS

A retrospective case series of 799 patients above 18 years old with spinal instrumentation surgery, between January 2010 and December 2014 in the traumatology and orthopaedic surgery department of our institution. All patients with SSIs were treated by debridement, graft replacement, retention of the instrumentation and lengthy courses of antimicrobial therapy. The patients were followed up for a period of 12 months.

RESULTS

Of all the patients with arthrodesis, 32 (4%) had spinal SSIs. Three patients were lost to follow-up. The final sample analyzed comprised 29 cases, with a median age of 54.9 years (IQR, 45.7-67 years) and a Charlson comorbidity index of 2.0 (IQR; 0-3). A microbiological diagnosis was obtained in 75.8% of the cases. Of these, the ISSs were monomicrobial in 68.2% and polymicrobial in 31.8%. Once treatment had been completed, 96% were cured without sequelae, and the rate of recurrence and reoperation was 4%.

CONCLUSIONS

Treatment based on debridement, retention of the instrumentation, graft replacement and lengthy courses of antimicrobial therapy seems a very effective strategy in the treatment of patients with deep surgical site infection in spine surgery.

Surgical Site Infection in Spine Surgery: Who Is at Risk?

STUDY DESIGN

Retrospective literature review of spine surgical site infection (SSI).

OBJECTIVE

To perform a review of SSI risk factors and more specifically, categorize them into patient and surgical factors.

METHODS

A review of published literature on SSI risk factors in adult spine surgery was performed. We included studies that reported risk factors for SSI in adult spinal surgery. Excluded are pediatric patient populations, systematic reviews, and meta-analyses. Overall, we identified 72 cohort studies, 1 controlled-cohort study, 1 matched-cohort study, 1 matched-paired cohort study, 12 case-controlled studies (CCS), 6 case series, and 1 cross-sectional study.

RESULTS

Patient-associated risk factors-diabetes mellitus, obesity (body mass index >35 kg/m²), subcutaneous fat thickness, multiple medical comorbidities, current smoker, and malnutrition were associated with SSI. Surgical associated factors-preoperative radiation/postoperative blood transfusion, combined anterior/posterior approach, surgical invasiveness, or levels of instrumentation were associated with increased SSI. There is mixed evidence of age, duration of surgery, surgical team, intraoperative blood loss, dural tear, and urinary tract infection/urinary catheter in association with SSI.

CONCLUSION

SSIs are associated with many risk factors that can be patient or surgically related. Our review was able to identify important modifiable and nonmodifiable risk factors that can be essential in surgical planning and discussion with patients.

Risk factors for surgical site infection following lumbar spinal surgery: a meta-analysis

Objective

To identify risk factors for surgical site infection (SSI) in patients who had undergone lumbar spinal surgery.

Methods

Studies published in PubMed, Web of Science, and Embase were systematically reviewed to determine risk factors for SSI following lumbar spinal surgery. Results are expressed as risk ratios (RRs) with 95% CIs and weighted mean difference (WMD) with 95% CI. A fixed-effect or random-effect model was used to pool the estimates according to heterogeneity among the studies included.

Results

Sixteen studies involving 13,393 patients were included in this meta-analysis. Pooled estimates suggested that diabetes (RR 2.19, 95% CI 1.43–3.36; P<0.001), obesity (RR 2.87, 95% CI 1.62–5.09; P<0.001), BMI (WMD 1.32 kg/m², 95% CI 0.39–2.25; P=0.006), prolonged operating time (WMD 24.96 minutes, 95% CI 14.77–35.15; P<0.001), prolonged hospital stay (WMD 2.07 days, 95% CI 0.28–3.87; P=0.024), hypertension (RR 1.28, 95% CI 1.08–1.52; P=0.005), and previous surgery (RR 2.06, 95% CI 1.39–3.06; P<0.001) were independent risk factors for SSI in patients who had undergone lumbar spine surgery. Current smoking (RR 0.89, 95% CI 0.75–1.06; P=0.178), American Society of Anesthesiologists grade >2 (RR 2.63, 95% CI 0.84–8.27; P=0.098), increased age (WMD 1.43 years, 95% CI −1.15 to 4.02; P=0.278), COPD (RR 1.21, 95% CI 0.68–2.17; P=0.521), cardiovascular disease (RR 1.63, 95% CI 0.40–6.70; P=0.495), rheumatoid arthritis (RR 1.76, 95% CI 0.53–5.90; P=0.359), and osteoporosis (RR 1.91, 95% CI 0.79–4.63; P=0.152) were not risk factors for postoperative SSI.

Conclusion

Our results identified several important factors that increased the risk of postoperative SSI. Knowing these risk factors, surgeons could adequately analyze and evaluate risk factors in patients and then develop prevention measurements to reduce the rate of SSI.

Recurrent Surgical Site Infections in the Spine After Treatment With the Vacuum-assisted Closure (VAC) System

STUDY DESIGN

This study retrospectively reviewed recurrences of surgical site infections (SSI) in spinal patients treated with vacuum-assisted closure (VAC) technology.

OBJECTIVE

Identify patient and treatment factors associated with recurrence of SSI after VAC treatment.

SUMMARY OF BACKGROUND DATA

Patients treated with VAC can achieve healing of deep spine wound infections; however, some patients develop a recurrent infection. Risk factors associated with a recurrence have not been identified.

MATERIALS AND METHODS

One hundred and eleven patients with SSI after spine surgery from 2002 to 2010 were studied. They had been treated with irrigation and debridement, placement of VAC, and IV antibiotics. They subsequently were taken to surgery for primary closure of their wound. Patients with SSI who healed after the initial infection treatment were compared with patients who experienced recurrence. Patient and treatment factors that were studied included smoking status, body mass index, obesity status, diagnosis of diabetes, fusion surgery, methicillin-resistant Staphylococcus aureus, or polybacteria infection, number of irrigation and debridement treatments before closure, duration of IV antibiotic treatment, and duration of treatment time with VAC. Patients with SSI who healed after the initial treatment were compared with patients who experienced recurrence.

RESULTS

Fourteen patients had at least one recurrence of wound infection. None of the patient or treatment factors was associated with the recurrence of a SSI.

CONCLUSIONS

Among spine surgery patients with a SSI treated with the VAC system, those factors which predispose a patient to develop a recurrent SSI remain unknown.

LEVEL OF STUDY

Level IV.

Clinical and Radiological Outcomes of Unilateral Biportal Endoscopic Decompression by 30° Arthroscopy in Lumbar Spinal Stenosis: Minimum 2-Year Follow-up

Background

Open microscopic laminectomy has been the standard surgical method for degenerative spinal stenosis without instability till now. However, it is associated with complications such as paraspinal muscle injury, excessive bleeding, and wound infection. Several surgical techniques, including microendoscopic decompression, have been introduced to solve these problems.

Methods

Authors analyzed retrospectively 55 patients presenting with neurological symptoms due to degenerative lumbar spinal stenosis refractory to conservative treatment. Patients with foraminal stenosis requiring foraminal decompression were excluded. Two or three portals were used for each level. One portal was used for viewing purpose and the others for instrument passage. Unilateral laminotomy was followed by bilateral decompression under the view of 30° arthroscopy. Clinical outcomes were evaluated using modified Macnab criteria, Oswestry disability index (ODI), and visual analogue scale (VAS). Postoperative complications were checked during the 2-year follow-up. Plain radiographs before and after surgery were compared to analyze the change of disc height decrement and alignment.

Results

ODI scores improved from 67.4 ± 11.5 preoperatively to 19.3 ± 12.1 at 2-year follow-up (p < 0.01). VAS scores of the leg decreased from 7.7 ± 1.5 to 1.7 ± 1.5 at the final follow-up (p < 0.01). Per the modified Macnab criteria, 81% of the patients improved to good/excellent. No cases of infection occurred. The intervertebral angle was significantly reduced from 6.26° ± 3.54° to 5.58° ± 3.23° at 2 years postoperatively (p = 0.027) and the dynamic intervertebral angle changed from 6.54° ± 3.71° to 6.76° ± 3.59°, which was not statistically significant (p = 0.562). No significant change in slippage was observed (3.76% ± 5.01% preoperatively vs. 3.81% ± 5.28% at the final follow-up [p = 0.531]). The dynamic percentage slip did not change significantly, from 2.65% ± 3.37% to 2.76% ± 3.71% (p = 0.985). However, intervertebral distance decreased significantly from 10.43 ± 2.23 mm to 10.0 ± 2.24 mm (p = 0.000).

Conclusions

Full endoscopic decompression using a 30° arthroscopy demonstrated a satisfactory clinical outcome at the 2-year follow-up. This technique reduces wound infection rate and did not bring about postoperative segmental spinal instability. It could be a feasible alternative to conventional open microscopic decompression or fusion surgery for degenerative lumbar spinal stenosis.

The impact of type 2 diabetes on the peri- and postoperative outcomes of minimally invasive fusion techniques in the lumbar spine

BACKGROUND

The impact of diabetes on spinal surgery has been studied extensively, but very few studies have focused on minimal access spinal technologies (MAST) and complication rates in patients suffering from type 2 diabetes (T2DM). Diabetes increases the risk of wound healing disorders, complication rate and length of stay in the hospital. We focused on the peri- and postoperative complications of MAST in an unselected consecutive population of 187 patients suffering from degenerative disorders lumbar spine disorders. Since mostly older patients are affected by degenerative lumbar changes, we concentrated on T2DM.

METHODS

We evaluated perioperative and postoperative complication rates associated with MAST fusion techniques in lumbar spine surgery in patients suffering from T2DM compared to patients without diabetes. Lumbar fusion was performed using interbody and posterolateral fusion.

RESULTS

Eighteen female and sixteen male patients suffered from T2DM (15.65% and 22.22% respectively). No differences between patients with and without T2DM concerning surgery-related complications including infections, severe wound healing disorders or length of in-hospital stay were noted. Peri- or postoperative complication rates, as well as blood loss volumes, were evenly distributed between the two groups.

CONCLUSIONS

T2DM is not a risk factor for the occurrence of complications in MAST.

The Rothman Index as a predictor of postdischarge adverse events after elective spine surgery

BACKGROUND CONTEXT

The Rothman Index (RI) is a comprehensive rating of overall patient condition in the hospital setting. It is used at many medical centers and calculated based on vital signs, laboratory values, and nursing assessments in the electronic medical record. Previous research has demonstrated an association with adverse events, readmission, and mortality in other fields, but it has not been investigated in spine surgery.

PURPOSE

The present study aims to determine the potential utility of the RI as a predictor of adverse events after discharge following elective spine surgery.

STUDY DESIGN/SETTING

This retrospective cohort study was carried out at a large academic medical center.

PATIENT SAMPLE

A total of 2,687 patients who underwent elective spine surgery between 2013 and 2016 were included in the present study.

OUTCOME MEASURES

The occurrence of adverse events and readmission after discharge from the hospital, within postoperative day 30, was determined in the present study.

METHODS

Patient characteristics and 30-day perioperative outcomes were characterized, with events being classified as "major adverse events" or "minor adverse events" using standardized criteria. Rothman Index scores from the hospitalization were analyzed and compared for those who did or did not experience adverse events after discharge. The association of lowest and latest scores on adverse events was determined with multivariate regression, controlling for demographics, comorbidities, surgical procedure, and length of stay.

RESULTS

Postdischarge adverse events were experienced by 7.1% of patients. The latest and lowest RI values were significantly inversely correlated with any adverse events, major adverse events, minor adverse events and readmissions after controlling for age, gender, body mass index, American Society of Anesthesiologists (ASA) class, surgical site, and hospital length of stay. Rates of readmission and any adverse event consistently had an inverse correlation with lowest and latest RI scores, with patients at increased risk with lowest score below 65 or latest score below 85.

CONCLUSIONS

The RI is a tool that can be used to predict postdischarge adverse events after elective spine surgery that adds value to commonly used indices such as patient demographics and ASA. It is found that this can help physicians identify high-risk patients before discharge and should be able to better inform clinical decisions.

Implementation of an infection prevention bundle and increased physician awareness improves surgical outcomes and reduces costs associated with spine surgery

OBJECTIVE

Previous studies have demonstrated the efficacy of infection prevention protocols in reducing infection rates. This study investigated the effects of the development and implementation of an infection prevention protocol that was augmented by increased physician awareness of spinal fusion surgical site infection (SSI) rates and resultant cost savings.

METHODS

A cohort clinical investigation over a 10-year period was performed at a single tertiary spine care academic institution. Preoperative infection control measures (chlorohexidine gluconate bathing, Staphylococcus aureus nasal screening and decolonization) followed by postoperative infection control measures (surgical dressing care) were implemented. After the implementation of these infection control measures, an awareness intervention was instituted in which all attending and resident neurosurgeons were informed of their individual, independently adjudicated spinal fusion surgery infection rates and rankings among their peers. During the course of these interventions, the overall infection rate was tracked as well as the rates for those neurosurgeons who complied with the preoperative and postoperative infection control measures (protocol group) and those who did not (control group).

RESULTS

With the implementation of postoperative surgical dressing infection control measures and physician awareness, the postoperative spine surgery infection rate decreased by 45% from 3.8% to 2.1% (risk ratio 0.55; 95% CI 0.32–0.93; p = 0.03) for those in the protocol cohort, resulting in an estimated annual cost savings of $291,000. This reduction in infection rate was not observed for neurosurgeons in the control group, although the overall infection rate among all neurosurgeons decreased by 54% from 3.3% to 1.5% (risk ratio 0.46; 95% CI 0.28–0.73; p = 0.0013).

CONCLUSIONS

A novel paradigm for spine surgery infection control combined with physician awareness methods resulted in significantly decreased SSI rates and an associated cost reduction. Thus, information sharing and physician engagement as a supplement to formal infection control measures result in improvements in surgical outcomes and costs.

Risk Factors for Surgical Site Infection After Posterior Lumbar Spinal Surgery

STUDY DESIGN

A retrospective study.

OBJECTIVE

The purpose of this study was to identify the independent risk factors for postoperative surgical site infection (SSI) after posterior lumbar spinal surgery based on the perioperative factors analysis.

SUMMARY OF BACKGROUND DATA

SSI is one of the most common complications after spinal surgery. Previous studies have identified different risk factors for postoperative SSI after lumbar spinal surgery. However, most of the studies were focused on the patient and procedure-related factors. Few studies reported the correlation between laboratory tests and postoperative SSI.

METHODS

A retrospective study was carried out in a single institution. Patients who underwent posterior lumbar spinal surgery between January 2010 and August 2016 were included in this study. All patients' medical records were reviewed and patients with postoperative SSI were identified. Perioperative variables were included to determine the risk factors for SSI by univariate and multivariate regression analysis.

RESULTS

A total of 2715 patients undergoing posterior lumbar spinal surgery were included in this study. Of these patients, 64 (2.4%) were detected with postoperative SSI, including 46 men and 18 women. Diabetes mellitus (P = 0.026), low preoperative serum level of calcium (P = 0.009), low preoperative and postoperative albumin (P = 0.025 and 0.035), high preoperative serum glucose (P = 0.029), multiple fusion segments (P < 0.001), increased surgical time and estimated blood loss (P = 0.023 and 0.005), decreased postoperative hemoglobin (P = 0.008), and prolonged drainage duration (P = 0.016) were found to be the independent risk factors for SSI. Multilevel fusion and a history of diabetes mellitus were the two strongest risk factors (odds ratio = 2.329 and 2.227) for SSI.

CONCLUSION

Based on a large population analysis, previous reported risk factors for SSI were confirmed in this study while some new independent risk factors were identified significantly associated with SSI following lumbar spinal surgery, including preoperative low serum level of calcium, decreased preoperative and postoperative albumin, and decreased postoperative hemoglobin.

LEVEL OF EVIDENCE

4.

Reduction in surgical site infection with suprafascial intrawound application of vancomycin powder in instrumented posterior spinal fusion: a retrospective case-control study

OBJECTIVE Recent studies have demonstrated the efficacy of subfascial intrawound application of vancomycin powder in spine surgery in reducing the rate of surgical site infections (SSIs). However, to date no study has evaluated the efficacy and safety of suprafascial application of vancomycin powder in spine surgery. The purpose of this study was to quantify the rate of SSIs after open instrumented posterior spinal fusion with and without application of suprafascial vancomycin powder and to evaluate the rate of vancomycin powder-related local adverse effects. METHODS The authors conducted a single-center retrospective case-control study of adult patients undergoing open instrumented posterior fusion of the cervical, thoracic, or lumbar spine performed by a single surgeon from January 2010 through December 2016. In March 2013, routine application of 1 g of suprafascial vancomycin powder was started for all cases in addition to standard systemic antibiotic prophylaxis. Baseline demographics and operative data as well as the SSI rates were compared between the study groups. The incidence of vancomycin powder-related adverse effects was analyzed. RESULTS A total of 515 patients (268 in the untreated group and 247 in the treated group) were included in the study. The mean age was significantly higher in the treated group than in the untreated group (58.4 vs 54.4 years, p < 0.01). Operative variables were similar between the study groups. Patients receiving vancomycin powder had a significantly lower infection rate (5.6% in the untreated group vs 0% in the treated group, p < 0.001). No vancomycin powder-related adverse effects were identified in the treated group. CONCLUSIONS Routine application of suprafascial intrawound vancomycin powder in addition to systemic antibiotic prophylaxis is an easy-to-use, safe, and effective strategy for preventing SSIs after instrumented posterior spinal fusion. Suprafascial application of vancomycin powder could be a valuable alternative to previously reported subfascial distribution, minimizing the risk of local adverse drug reactions.

Management of spinal infection: a review of the literature

Spinal infection (SI) is defined as an infectious disease affecting the vertebral body, the intervertebral disc, and/or adjacent paraspinal tissue and represents 2–7% of all musculoskeletal infections. There are numerous factors, which may facilitate the development of SI including not only advanced patient age and comorbidities but also spinal surgery. Due to the low specificity of signs, the delay in diagnosis of SI remains an important issue and poor outcome is frequently seen. Diagnosis should always be supported by clinical, laboratory, and imaging findings, magnetic resonance imaging (MRI) remaining the most reliable method. Management of SI depends on the location of the infection (i.e., intraspinal, intervertebral, paraspinal), on the disease progression, and of course on the patient’s general condition, considering age and comorbidities. Conservative treatment mostly is reasonable in early stages with no or minor neurologic deficits and in case of severe comorbidities, which limit surgical options. Nevertheless, solely medical treatment often fails. Therefore, in case of doubt, surgical treatment should be considered. The final result in conservative as well as in surgical treatment always is bony fusion. Furthermore, both options require a concomitant antimicrobial therapy, initially applied intravenously and administered orally thereafter. The optimal duration of antibiotic therapy remains controversial, but should never undercut 6 weeks. Due to a heterogeneous and often comorbid patient population and the wide variety of treatment options, no generally applicable guidelines for SI exist and management remains a challenge. Thus, future prospective randomized trials are necessary to substantiate treatment strategies.