title: The incidence and risk factors for surgical site infection after clean spinal operations: A prospective cohort study and review of the literature Surgical Wound Infection Rates and Risk Factors in Spinal Fusion in a University Teaching Hospital in Madrid, Spain Surgical site infections following operative management of cervical spondylotic myelopathy: prevalence, predictors of occurence, and influence on peri-operative outcomes The Impact of Current Smoking and Smoking Cessation on Short-Term Morbidity Risk After Lumbar Spine Surgery Perioperative and delayed complications associated with the surgical treatment of cervical spondylotic myelopathy based on 302 patients from the AOSpine North America Cervical Spondylotic Myelopathy Study. Mortality and morbidity after spinal surgery in patients with Parkinson's disease: a retrospective matched-pair cohort study. Early surgical site infections in adult spinal trauma: a prospective, multicentre study of infection rates and risk factors. Predictors of Hospital Readmission and Surgical Site Infection in the United States, Denmark, and Japan: Is Risk Stratification a Universal Language? Does Minimally Invasive Surgery Have a Lower Risk of Surgical Site Infections Compared With Open Spinal Surgery? Infection Rate After Transoral Approach for the Upper Cervical Spine Intraoperative Fraction of Inspired Oxygen Is a Modifiable Risk Factor for Surgical Site Infection after Spinal Surgery Prospective multicenter surveillance and risk factor analysis of deep surgical site infection after posterior thoracic and/or lumbar spinal surgery in adults Risk factors for deep surgical site infections after spinal fusion Preoperative prealbumin level as a risk factor for surgical site infection following elective spine surgery Risk Factors for Infection After Spinal Surgery Deep-wound and organ-space infection after surgery for degenerative spine disease: an analysis from 2006 to 2012 Risk Factors for Postoperative Spinal Wound Infections After Spinal Decompression and Fusion Surgeries Surgical-site infection in spinal injury: incidence and risk factors in a prospective cohort of 518 patients Malnutrition Predicts Infectious and Wound Complications Following Posterior Lumbar Spinal Fusion Predicting surgical site infection after spine surgery: a validated model using a prospective surgical registry. Diabetes and Early Postoperative Outcomes Following Lumbar Fusion Risk factors for surgical site infection in elective routine degenerative lumbar surgeries. Patient factors, comorbidities, and surgical characteristics that increase mortality and complication risk after spinal arthrodesis: a prognostic study based on 5,887 patients. Postoperative Surgical Site Infections in Patients Undergoing Spinal Tumor Surgery: Incidence and Risk Factors Development of an Index to Characterize the “Invasiveness” of Spine Surgery: Validation by Comparison to Blood Loss and Operative Time Risk factors for surgical site infection after posterior cervical spine surgery: an analysis of 5,441 patients from the ACS NSQIP 2005-2012. Medicaid Status Is Associated With Higher Surgical Site Infection Rates After Spine Surgery Intraoperative and Early Postoperative Complications in Extreme Lateral Interbody Fusion: An Analysis of 600 Cases
abstract: Background : Postoperative infection is one of the most common complications after spine surgeries . In our study , surgical site infection ( SSI ) is described as ; superficial ( i.e. , skin and subcutaneous tissues ) and deep ( i.e. , fascia and muscles ) infections occurring in the short term ( i.e. , 1-month ) after spine surgeries ( Centers for Disease Control and Prevention definition 81.00–81.08 ) . To detect the risk factors for the occurrence of such a complication , studies require a large number of patients , a high quality of data and adequate analysis . In this study , we prospect ively enrolled 987 patients undergoing spinal surgery over a 3 years period . Methods : From November 2010 to November 2013 , 987 patients had a variety of spinal operations that included ; disc herniation , spinal stenosis , spondylolisthesis , fracture-dislocations , spine and spinal cord tumors , and syringomyelia . Patients under the age of 10 , those with a recent history of infection and antibiotherapy , and patients with immunodeficiency disorders were excluded . Results : Of the 987 spine procedures performed , 27 ( 2.73 % ) developed postoperative infections . Multi-variant data analysis indicated that multiple factors correlated with an increased risk of SSI in descending order ; trauma , a past history of diabetes , smoking , being confined to bed , in the perioperative period , mean blood sugar levels above 120 mg/dl , longer lengths of incisions , and longer hospital stay . Conclusion : Considering the preventable nature of most of the factors contributing to SSI , it should be possible to reduce these complications Study Design . Prospect i ve cohort study . Objective . To study risk factors linked to spinal fusion surgical wound infection ( SWI ) incidence and compare the incidence with rates in Madrid Region , Spain and United States as a whole . Summary of Background Data . SWI is one of the complications posed by spinal surgery . Indeed , spinal surgery has a higher infection rate than do other orthopedic surgeries such as total hip or knee arthroplasty . The study of risk factors that are susceptible to be modified will enable both the incidence of SWI and , by extension , related morbidity , mortality , and costs to be reduced . Methods . All patients undergoing spinal fusion at a tertiary hospital from June 2011 to June 2014 were included .  Infection rate was calculated , and the association between risk factors and SWI incidence was assessed by reference to odds ratio ( OR ) with univariate and multivariate analysis . Results . The study population ( n = 892 ) had a SWI rate of 3.9 % . The st and ardized infection ratio of our hospital was 0.58 with respect to the Madrid Region , 0.76 with respect to Spain 's national rate and 2.05 with respect to the US NHSN/CDC . The multivariate analysis showed that predictive factors of SWI were diabetes mellitus ( OR 2.81 , 95 % confidence interval , CI : 1.18–6.72 , P < 0.05 ) , chronic obstructive pulmonary disease ( COPD ) ( OR 5.16 , 95 % CI : 2.04–13.08 , P < 0.05 ) , duration of surgery higher than the 75th percentile ( OR 5.39 , 95 % CI : 1.77–110.84 , P < 0.05 ) and dirty surgery ( OR 14.01 , 95 % CI : 1.01–28.88 , P < 0.05 ) . Conclusion . Independent risk factors for SWI in spinal fusion are existence of diabetes mellitus , COPD , duration of surgery higher than the 75th percentile and dirty surgery . Knowing these risk factors enables action to be taken to reduce the SWI rate . Level of Evidence : Purpose Studies have examined  infection rates following spine surgery  and their relationship to post-operative complications and increased length of stay . Few studies , however , have investigated predictors of infection , specifically in the setting of operative intervention for cervical spondylotic myelopathy ( CSM ) . This study aims to identify the incidence and factors predictive of infection amongst this cohort . Methods This study performed a retrospective review of the prospect ively collected American College of Surgeons National Surgical Quality Improvement Program ( NSQIP ) data base . Patients included those treated surgically for CSM ( ICD-9 code 721.1 ) from 2010 to 2012 . Patient demographics and surgical data were collected with outcome variables including the occurrence of one of the following surgical site infections ( SSIs ) within 30 days of index operation : superficial SSI , deep incisional SSI , and organ/space SSI . Results 3057 patients were included in this analysis .  Overall infection rate was 1.15 % ( 35/3057 ) , of which 54.3 % ( 19/35 ) were superficial SSIs , 28.6 % ( 10/35 ) were deep incisional SSI , and 20 % ( 7/35 ) were peri-spinal SSI . Logistic regression revealed factors associated with SSI included : higher BMI [ OR 1.162 ( CI 1.269–1.064 ) , p = 0.001 ] and operative time ≥208 min [ OR 4.769 ( CI 20.220–1.125 ) , p = 0.034 ] . Conclusions The overall SSI rate for the examined CSM cohort was 1.15 % . This study identified increased BMI and operative time ≥208 min as predictors of infection in surgical CSM patients . This information should be carefully considered in delivering patient education and future efforts to optimize risk in CSM patients indicated for surgical intervention Study Design . A retrospective review of prospect ively collected data . Objective . The aim of this study was to determine the impact of current smoking or prior smoking cessation on 30-day morbidity risk following lumbar spine surgery . Summary of Background Data . Prior studies have reported conflicting data regarding the impact of smoking on morbidity risk , and few studies have investigated smoking cessation . Methods . A large , multicenter , prospect ively collected clinical registry was queried for all adult patients undergoing lumbar spine surgery in 2012 and 2013 , and 35,477 cases were identified .  Morbidity data are collected by on-site clinical personnel for 30 days postoperatively . Patients were divided into categories of “ never-smoker , ” for patients with no reported cigarette use ( n = 27,246 ) , “ former smoker , ” for patients who quit smoking more than 12 months before surgery ( n = 562 ) , and “ current smoker , ” for patients still using cigarettes ( n = 7669 ) . A univariate analysis was conducted to identify un-adjusted differences in morbidity risk , and a multivariate analysis was conducted in an attempt to control for confounders . Results . In the multivariate analysis , current smokers had a significantly higher risk of both superficial surgical site infection and overall wound complications , than never-smokers ( P < 0.05 for each ) . Current smokers also had a significantly higher risk of total 30-day morbidity ( P = 0.04 ) . There was a trend toward former smokers also having an increased risk , but this did not reach significance in any category . Patients with a pack-year smoking history of 1 to 20 pack-years and more than 40 pack-years both had a significantly higher risk of superficial surgical site infections ( P < 0.05 for each ) . Conclusion . Current smoking is associated with a small but significant increase in systemic morbidity and wound complications following elective lumbar spine procedures . Increasing pack year history was also associated with wound complication risk , suggesting a dose-related effect . The data provide preliminary support for future studies on smoking cessation . Level of Evidence : OBJECT Rates of complications associated with the surgical treatment of cervical spondylotic myelopathy ( CSM ) are not clear . Appreciating these risks is important for patient counseling and quality improvement . The authors sought to assess the rates of and risk factors associated with perioperative and delayed complications associated with the surgical treatment of CSM . METHODS Data from the AOSpine North America Cervical Spondylotic Myelopathy Study , a prospect i ve , multicenter study , were analyzed . Outcomes data , including adverse events , were collected in a st and ardized manner and externally monitored . Rates of perioperative complications ( within 30 days of surgery ) and delayed complications ( 31 days to 2 years following surgery ) were tabulated and stratified based on clinical factors . RESULTS The study enrolled 302 patients ( mean age 57 years , range 29 - 86 ) years . Of 332 reported adverse events , 73 were classified as perioperative complications ( 25 major and 48 minor ) in 47 patients ( overall perioperative complication rate of 15.6 % ) . The most common perioperative complications included minor cardiopulmonary events ( 3.0 % ) , dysphagia ( 3.0 % ) , and superficial wound infection ( 2.3 % ) . Perioperative worsening of myelopathy was reported in 4 patients ( 1.3 % ) . Based on 275 patients who completed 2 years of follow-up , there were 14 delayed complications ( 8 minor , 6 major ) in 12 patients , for an overall delayed complication rate of 4.4 % . Of patients treated with  anterior-only  ( n = 176 ) ,  posterior-only  ( n = 107 ) , and combined anterior-posterior ( n = 19 ) procedures , 11 % , 19 % , and 37 % , respectively , had 1 or more perioperative complications . Compared with anterior-only approaches , posterior-only approaches had a higher rate of wound infection ( 0.6 % vs 4.7 % , p = 0.030 ) . Dysphagia was more common with combined anterior-posterior procedures ( 21.1 % ) compared with anterior-only procedures ( 2.3 % ) or posterior-only procedures ( 0.9 % ) ( p < 0.001 ) . The incidence of C-5 radiculopathy was not associated with the surgical approach ( p = 0.8 ) . The occurrence of perioperative complications was associated with increased age ( p = 0.006 ) , combined anterior-posterior procedures ( p = 0.016 ) , increased operative time ( p = 0.009 ) , and increased operative blood loss ( p = 0.005 ) , but it was not associated with comorbidity score , body mass index , modified Japanese Orthopaedic Association score , smoking status , anterior-only versus posterior-only approach , or specific procedures . Multivariate analysis of factors associated with minor or major complications identified age ( OR 1.029 , 95 % CI 1.002 - 1.057 , p = 0.035 ) and operative time ( OR 1.005 , 95 % CI 1.002 - 1.008 , p = 0.001 ) . Multivariate analysis of factors associated with major complications identified age ( OR 1.054 , 95 % CI 1.015 - 1.094 , p = 0.006 ) and combined anterior-posterior procedures ( OR 5.297 , 95 % CI 1.626 - 17.256 , p = 0.006 ) . CONCLUSIONS For the surgical treatment of CSM , the vast majority of complications were treatable and without long-term impact . Multivariate factors associated with an increased risk of complications include greater age , increased operative time , and use of combined anterior-posterior procedures BACKGROUND CONTEXT There is a lack of information about postoperative outcomes and related risk factors associated with spinal surgery in patients with Parkinson 's disease ( PD ) . PURPOSE This study aim ed to investigate the postoperative morbidity and mortality associated with spinal surgery for patients with PD , and the risk factors for poor outcomes . STUDY DESIGN This is a retrospective matched-pair cohort study . PATIENT SAMPLE Data of patients who underwent elective spinal surgery between July 2010 and March 2013 were extracted from the Diagnosis Procedure Combination data base , a nationwide inpatient data base in Japan . OUTCOME MEASURES In-hospital mortality and occurrence of postoperative complications . METHODS For each patient with PD , we r and omly selected up to four age- and sex-matched controls in the same hospital in the same year . The differences in in-hospital mortality and occurrence of postoperative complications were compared between patients with PD and controls . A multivariable logistic regression model fitted with a generalized estimation equation was used to identify significant predictors of major complications ( surgical site infection , sepsis , pulmonary embolism , respiratory complications , cardiac events , stroke , and renal failure ) . Multiple imputation was used for missing data . RESULTS Among 154,278 patients undergoing spinal surgery , 1,423 patients with PD and 5,498 matched controls were identified .  Crude in-hospital mortality was higher in patients with PD than in controls ( 0.8 % vs. 0.3 % , respectively ) . The crude proportion of major complications was also higher in patients with PD ( 9.8 % vs. 5.1 % in controls ) . Postoperative delirium was more common in patients with PD ( 30.3 % ) than in controls ( 4.3 % ) . Parkinson 's disease was a significant predictor of major postoperative complications , even after adjusting for other risk factors ( odds ratio , 1.74 ; 95 % confidence intervals , 1.37 - 2.22 ; p<.001 ) . CONCLUSIONS Patients with PD had a significantly increased risk of postoperative complications following spinal surgery .  Postoperative delirium was the most frequently observed complication INTRODUCTION Spine surgery is known to have a high risk of surgical site infection ( SSI ) . Multiple studies have looked into the risk factors and incidence of SSI during elective surgery , but only two retrospective studies have specifically evaluated SSI during surgery following spine trauma . MATERIAL S AND METHODS This work was based on a prospect i ve cohort study that included all the patients operated on for spinal trauma at 13 French hospitals over a three-month period . The main endpoint was the occurrence of a SSI during the three-month period . Patients with multiple trauma or open fractures were excluded from the study . RESULTS Of the 169 patients re-examined after a minimum of three months , six had had an acute SSI ( 3.55 % ) . The following factors were significantly related to a SSI : age , ASA score , diabetes , procedure duration , delay elapsed between accident and procedure , number of levels fused , bleeding and prolonged presence of urinary catheter . DISCUSSION Our results were consistent with the published infection rates of 2 to 10 % . The risk factors identified have all been described in previous studies on elective spine surgery . LEVEL OF EVIDENCE Level IV , prospect i ve cohort study Study Design . Retrospective review of three spine surgery data bases . Objectives . The purpose of the present study is to determine whether predictors of  hospital readmission and surgical site infection ( SSI )  after lumbar fusion will be the same in United States , Denmark , and Japan . Summary of Background Data . Because clinical decision making becomes more data driven , risk stratification will be crucial to minimize complications . Spine surgeons worldwide face this issue , leading to parallel efforts to address risk stratification . This raises the question as to whether pooled data would be valuable and whether models generated in one country would be applicable to other population s. Methods . Predictors of SSI and 30-day readmission from three prospect i ve data bases ( National Neurosurgery Quality and Outcomes Data base [ N2QOD ] N = 2653 , DaneSpine N = 1993 , Japan Multicenter Spine Data base [ JAMSD ] N = 3798 ) were determined and compared to identify common or divergent predictive risks . Results . Predictive variables differed in the three data bases , for both readmission and SSI . Factors predictive for hospital readmission were American Society of Anesthesiologists ( ASA ) grade in N2QOD ( P = 0.013 , odds ratio [ OR ] 2.08 ) , fusion levels in DaneSpine ( P = 0.005 , OR 1.67 ) , and sex in JAMSD ( P = 0.001 , OR = 2.81 ) . Associated differences in demographics and procedural factors included mean ASA grade ( N2QOD = 2.45 , JAMSD = 1.72 ) and fusion levels ( N2QOD = 1.39 , DaneSpine = 1.52 , JAMSD = 1.34 ) . For SSI , sex ( P = 0.000 , OR = 3.30 ) , diabetes ( P = 0.000 , OR = 2.90 ) , and length of stay ( P = 0.000 , OR = 1.02 ) were predictive in JAMSD . No predictors were identified in N2QOD or DaneSpine . Conclusion . Predictors of SSI and hospital readmission differ in the United States , Denmark , and Japan , suggesting that risk stratification models may need to be population specific or adjusted . Some differences in measured parameters exist in the three data bases analyzed ; however , patient and procedure selection also appear to differ and may limit the ability to directly pool data from different regions . Therefore , risk stratification models developed in one country may not be directly applicable to other countries . Level of Evidence : Background Surgical site infection ( SSI ) ranges from 1.9 % to 5.5 % in most large series . Minimally invasive surgery ( MIS ) has been postulated to reduce SSI rates . Questions / purpose s(1 ) Is MIS associated with a lower incidence of SSI compared with open spinal surgery ? ( 2 ) Are there other independent risk factors associated with SSI ? ( 3 ) What bacteria are most common in spinal SSI ? Methods Medical records of 2299 patients who underwent transforaminal lumbar interbody fusion , laminectomy , or discectomy  were analyzed and selected for a nested case-control analysis . Twenty-seven cases with SSI were matched with 162 control subjects without SSI stratified based on procedure performed within 28 days of the case ’s date of surgery . Patients were identified from an institutional data base at a tertiary care hospital .  MIS involved spinal procedures performed through a tubular retractor system . Univariate and multivariate analyses were performed . Results Patients undergoing open spinal surgery were 5.77 times more likely to develop SSI compared with MIS approaches ( odds ratio [ OR ] , 5.77 ; 95 % confidence interval [ CI ] , 1.0–32.7 ; p = 0.048 ) . Also , from the multivariate regression model , diabetes ( OR , 4.7 ; 95 % CI , 1.3–17.0 ; p = 0.018 ) , number of levels operated on ( OR , 3.5 ; 95 % CI , 1.6–7.5 ; p = 0.001 ) , and body mass index ( OR , 1.2 ; 95 % CI , 1.0–1.3 ; p = 0.010 ) were predictive of an increased risk in SSI . Staphylococcus aureus was most frequently identified , being present in 12 of 21 ( 52.4 % ) patients in whom positive cultures were obtained . Four of the 12 patients had methicillin-resistant S aureus infection . Conclusions In our series , MIS has a lower incidence of SSI . The risk factors predictive of SSI should be further evaluated in well- design ed prospect i ve trials . Level of Evidence Level III , therapeutic study . See Guidelines for Authors for a complete description of levels of evidence Study Design . A retrospective review of prospect ively collected data bases of 139 consecutive patients who underwent transoral surgery for lesions of the upper cervical spine . Objective . To analyze the incidence and risk factors of local infection after  transoral surgery  for the craniocervical junction in a single institution and to compare the findings with the literature . Summary of Background Data . One of the primary risks associated with transoral approach for lesions in the upper cervical spine is postoperative surgical wound infection . Methods . From April 1994 to December 2012 , 139 consecutive transoral surgical procedures were performed at a single referral center . The mean age at presentation was 53.6 years ( range : 5–87 yr ) , and more than half of the patients were males ( 58.3 % ) . The majority of cases were experiencing rheumatic diseases ( 43.9 % ) , whereas tumor destruction was the indication for surgery in 23.7 % of the cases . A total of 23 % had fracture of the upper cervical spine and primary infection was found in 7 patients ( 5 % ) . The mean follow-up period was 4.5 years . Results . Infection of the pharyngeal wound occurred in 5 patients ( 3.6 % ) , solely in the rheumatic and tumor groups . The presentation was mostly in the first 4 months . A single patient with cage reconstruction after giant cell tumor C2 presented with a late infection 5 years postoperatively . Debridement and primary closure was possible in 2 patients , whereas flap coverage of the pharyngeal wall was necessary in 3 patients . The presence of implant did not have a statistically significant effect on the occurrence of infection . However , infection in the presence of titanium cage mostly necessitated flap coverage of the pharyngeal wall after removal of the cage . Conclusion . The transoral route has proved to be an invaluable method of approaching pathological lesions in the upper cervical spine . The infection rate in this work was 3.6 % . Patients with rheumatic diseases and patients presenting with tumors were more susceptible to postoperative surgical wound infection . Level of Evidence : Background : Surgical site infections ( SSI ) after spinal surgery increase morbidity , mortality , length of hospital stay , and costs . Most previously identified risk factors for these infections , such as severity of illness and procedure duration , are not amenable to intervention . This study sought to identify modifiable risk factors associated with SSI after spinal surgery . Methods : This is a case-control study including case identification and review of medical records . A total of 104 patients with SSI after spinal surgery were compared to 104 r and omly selected control patients without SSI after spinal surgery in a 926-bed tertiary care hospital in Baltimore , Maryl and , between April 1 , 2001 and December 31 , 2004 . Results : Multivariate analysis identified independent risk factors for SSI after spinal surgery including prolonged procedure duration ( odds ratio [ OR ] , 4.7 ; 95 % confidence interval [ 95 % CI ] , 1.6–14 ; P < 0.001 ) , American Society of Anesthesiologists score of 3 or greater ( OR , 9.7 ; 95 % CI , 3.7–25 ; P < 0.001 ) , lumbar-sacral operative level ( OR , 2.9 ; 95 % CI , 1.2–7.1 ; P = 0.02 ) , posterior approach ( OR , 3.5 ; 95 % CI , 1.2–9.7 ; P = 0.02 ) , instrumentation ( OR , 2.5 ; 95 % CI , 1.1–6.0 ; P = 0.03 ) , obesity ( OR , 4.0 ; 94 % CI , 1.6–10 ; P < 0.01 ) , razor shaving before surgery ( OR , 3.6 ; 95 % CI , 1.2–11 ; P = 0.02 ) , and intraoperative administered fraction of inspired oxygen of less than 50 % ( OR , 12 ; 94 % CI , 4.5–33 ; P < 0.001 ) . Conclusions : In addition to previously reported risk factors , this study identified intraoperative administered fraction of inspired oxygen of less than 50 % as an independent , modifiable risk factor for SSI after spinal surgery . Intraoperative administration of at least 50 % fraction of inspired oxygen should be tested prospect ively as an intervention to prevent SSI after spinal surgery Background Surgical site infection is a serious and significant complication after spinal surgery and is associated with high morbidity rates , high healthcare costs and poor patient outcomes . Accurate identification of risk factors is essential for developing strategies to prevent devastating infections . The purpose of this study was to identify independent risk factors for surgical site infection among posterior thoracic and /or lumbar spinal surgery in adult patients using a prospect i ve multicenter surveillance research method . Methods From July 2010 to June 2012 , we performed a prospect i ve surveillance study in adult patients who had developed surgical site infection after undergoing thoracic and /or lumbar posterior spinal surgery at 11 participating hospitals . Detailed preoperative and operative patient characteristics were prospect ively recorded using a st and ardized data collection format . Surgical site infection was based on the definition established by the Centers for Disease Control and Prevention . Results A total of 2,736 consecutive adult patients were enrolled , of which 24 ( 0.9 % ) developed postoperative deep surgical site infection . Multivariate regression analysis indicated four independent risk factors . Preoperative steroid therapy ( P = 0.001 ) , spinal trauma ( P = 0.048 ) and gender ( male ) ( P = 0.02 ) were statistically significant independent patient-related risk factors , whereas an operating time ≥3 h ( P < 0.001 ) was a surgery-related independent risk factor . Conclusion Preoperative steroid therapy , spinal trauma , male gender and an operating time ≥3 h were independent risk factors for deep surgical site infection after thoracic and /or lumbar spinal surgery in adult patients . Identification of these risk factors can be used to develop protocol s aim ed at decreasing the risk of surgical site infection Surgical site infections ( SSI ) are undesired and troublesome complications after spinal surgery . The reported infection rates range from 0.7 to 11.9 % , depending on the diagnosis and the complexity of the procedure . Besides operative factors , patient characteristics could also account for increased infection rates . Because the medical , economic and social costs of SSI are enormous , any significant reduction in risks will pay dividends . The purpose of this study is to compare patients who developed deep SSI following lumbar or thoracolumbar spinal fusion with a r and omly selected group of patients who did not develop this complication in order to identify changeable risk factors . With a case – control analysis nested in a historical cohort of patients who had had a spinal fusion between January 1999 and December 2008 , we identified 36 cases with deep SSI ( CDC criteria ) . Information regarding patient-level and surgical-level risk factors was derived from st and ardized but routinely recorded data and compared with those acquired in a r and om selection of 135 uninfected patients . Univariate analyses and a multivariate logistic regression were performed . The overall rate of infection in 1,615 procedures ( 1,568 patients ) was 2.2 % . A positive history of spinal surgery was associated with an almost four times higher infection rate ( OR = 3.7 , 95 % BI = 1.6–8.6 ) . The risk of SSI increased with the number of levels fused , patients with diabetes had an almost six times higher risk and smokers had more than a two times higher risk for deep SSI . The most common organism cultured was Staphylococcus aureus . All infected patients underwent at least one reoperation , including an open débridement and received appropriate antibiotics to treat the organism . Patients who had had a previous spinal surgery are a high-risk group for infection compared with those that never had surgery . Total costs associated with preventive measures are substantial and should be compensated by health care insurance companies by means of separate clinical pathways . High-risk patients should be informed about the increased risk of complications Background : Nutritional status is a critical factor in patient outcomes in a variety of medical context s. In the surgical fields , there is substantial evidence suggesting that clinical outcomes including infection risk and surgical efficacy may be affected by preoperative nutritional status . The purpose of this study is to evaluate preoperative serum prealbumin levels , the currently preferred serum biomarker of nutritional deficiency , in relation to the risk of developing a surgical site infection . Methods : A retrospective case – control series was conducted comparing prospect ively collected preadmission serum prealbumin levels  to the risk for surgical site infection following elective spine surgery .  The analysis was conducted under an approved institutional quality assurance protocol . Patients were identified by querying the department billing codes for deep wound washouts over a 3-year period . A cohort of 32 patients with preoperative prealbumin levels who underwent spine surgery complicated by postoperative deep tissue infection was identified . This was compared against a case – control cohort of 74 patients who underwent spine surgery and did not experience postoperative infection . Clinical variables included demographic information , body mass index , smoking , diabetes , steroid use , length of the procedure , and length of hospital stay . The data were analyzed using multivariate Cox regression . Results : Two variables : Preoperative prealbumin < 20 and diabetes were both statistically significant predictors for the risk of developing a postoperative infection with hazard ratios of 2.12 ( 95 % confidence interval [ CI ] : 1.03–4.37 ) and 2.22 ( 95 % CI : 1.04–4.75 ) , respectively . Conclusions : Our results reinforce the relationship between preoperative nutritional status and outcomes in elective spine surgery . The data indicate that preoperative prealbumin levels may be useful in risk stratification . Further study is needed to determine whether nutritional supplementation may reduce the risk of infection Study Design . A retrospective case control analysis of 48 cases of postoperative infection following spinal procedures .  Objectives . Spinal procedures that became infected after surgery were analyzed to identify the significance of preoperative and intraoperative risk factors . Characterization of the nature and timing of the infections was also performed . Summary of Background Data . The rate of postoperative infection following  spinal surgery  varies widely depending on the nature of the procedure and the patient ’s diagnosis . Preoperative comorbidities and risk factors also influence the likelihood of infection . Methods . A review of 1629 procedures performed on 1095 patients revealed that a postoperative infection  developed in 48 patients ( 4.4 % ) . Data regarding preoperative and intraoperative risk factors were gathered from patient charts for these and a r and omly selected control group of 95 uninfected patients . For analysis , these patient groups were further divided into adult and pediatric subgroups , with an age cutoff of 18 years . Preoperative risk factors review ed included smoking , diabetes , previous surgery , previous infection , steroid use , body mass index , and alcohol abuse . Intraoperative factors review ed included staging of procedures , estimated blood loss , operating time , and use of allograft or instrumentation . Results . The majority of infections occurred during the early postoperative period ( less than 3 months ) . Age > 60 years , smoking , diabetes , previous surgical infection , increased body mass index , and alcohol abuse were statistically significant preoperative risk factors . The most likely procedure to be complicated by an infection was a combined anterior/posterior spinal fusion performed in a staged manner under separate anesthesia . Infections were primarily monomicrobial , although 5 patients had more than 4 organisms identified . The most common organism cultured from the wounds was Staphylococcus aureus . All patients were treated with surgical irrigation and débridement , and appropriate antibiotics to treat the cultured organism . Conclusions . Aggressive treatment of patients undergoing complex or prolonged spinal procedures is essential to prevent and treat infections . Underst and ing a patient ’s preoperative risk factors may help the physician to optimize a patient ’s preoperative condition . Additionally , awareness of critical intraoperative parameters will helpto optimize surgical treatment . It may be appropriate to increase the duration of prophylactic antibiotics or implement other measures to decrease the incidence of infection for high risk patients Objective : To study the incidence and risk factors of deep-wound and organ-space surgical site infection ( SSI ) following surgery for degenerative spine disease . Methods : Data from the American College of Surgeons National Surgical Quality Improvement Program were obtained for the years 2006–2012 . All adult patients over 40 years of age who underwent elective cervical or lumbar spine surgery for degenerative spine disease were identified .  Rates of deep-wound and organ-space SSI were calculated for each procedure . A multivariate logistic regression analysis was conducted to identify independent risk factors for SSI development . Results : A total of 36,440 patients were identified , with 7,627 patients ( 20.93 % ) undergoing cervical spine surgery and 28,813 patients ( 79.07 % ) undergoing lumbar spine surgery .  The overall rate of SSI was 0.72 % ( n = 264 ) ; there were 189 deep-wound infections ( 0.52 % ) and 75 organ-space infections ( 0.21 % ) . The highest rates of SSI were for patients undergoing a posterolateral fusion of the lumbar spine ( 1.04 % ) , followed by patients undergoing a posterior cervical decompression ( 1.02 % ) ; the lowest rates were for patients undergoing cervical disc replacement ( 0.00 % ) . The multivariate analysis revealed that chronic steroid use ( OR 3.66 ) and increasing operative time ( OR 1.002 ) were the strongest independent risk factors for SSI development in the cervical spine , and renal morbidity ( OR 3.93 ) , hemato-oncological morbidity ( OR 2.55 ) , and chronic steroid use ( 2.04 ) were the strongest risk factors for lumbar SSI . Additionally , patients with a SSI had longer lengths of stay and higher mortality rates ( 0.76 % ) when compared to patients without a SSI ( 0.09 % ) . Conclusion : Deep-wound and organ-space infections are severe complications in patients undergoing spine surgery . In this study of a multi-centre and prospect ively collected data base , the rate of SSI was 0.72 % . Patients with renal disorders , chronic steroid use , hemato-oncological disease , and diabetes , among others , had significantly higher odds of SSI development Study Design . This is a multivariate analysis of a prospect ively collected data base . Objective . To determine preoperative , intraoperative , and patient characteristics that contribute to an increased risk of postoperative wound infection in patients undergoing spinal surgery .  Summary of Background Data . Current literature sites a postoperative infection rate of approximately 4 % ; however , few have completed multivariate analysis to determine factors which contribute to risk of infection . Methods . Our study identified patients who underwent a spinal decompression and fusion between 1997 and 2006 from the Veterans Affairs ’ National Surgical Quality Improvement Program data base .  Multivariate logistic regression analysis was used to determine the effect of various preoperative variables on postoperative infection . Results . Data on 24,774 patients were analyzed .  Wound infection was present in 752 ( 3.04 % ) patients , 287 ( 1.16 % ) deep , and 468 ( 1.89 % ) superficial . Postoperative infection was associated with longer hospital stay ( 7.12 vs. 4.20 days ) , higher 30-day mortality ( 1.06 % vs. 0.5 % ) , higher complication rates ( 1.24 % vs. 0.05 % ) , and higher return to the operating room rates ( 37 % vs. 2.45 % ) . Multivariate logistic regression identified insulin dependent diabetes ( odds ratios [ OR ] = 1.50 ) , current smoking ( OR = 1.19 ) ASA class of 3 ( OR = 1.45 ) or 4 to 5 ( OR = 1.66 ) , weight loss ( OR = 2.14 ) , dependent functional status ( 1.36 ) preoperative HCT < 36 ( 1.37 ) , disseminated cancer ( 1.83 ) , fusion ( OR = 1.24 ) and an operative duration of 3 to 6 hours ( OR = 1.33 ) or > 6 hours ( OR = 1.40 ) as statistically significant predictors of postoperative infection . Conclusion . Using multivariate analysis of a large prospect ively collected data from the National Surgical Quality Improvement Program data base , we identified the most important risk factors for increased postoperative spinal wound infection . We have demonstrated the high mortality , morbidity , and hospitalization costs associated with postoperative spinal wound infections . The information provided should help alert clinicians to presence of these risks factors and the likelihood of higher postoperative infections and morbidity in spinal surgery patients Purpose To investigate the incidence of surgical-site infection ( SSI ) and determinate the risk factors of SSI in the context of spinal injury . Methods From February 1 , 2011 to July 31 , 2011 , for a multicentre cohort of patients with acute spinal injury , we prospect ively censored those with SSI for at least 12 months . We recorded epidemiologic characteristics and details of surgical procedure and postoperative care for each patient . We calculated the incidence of SSI at 1 , 3 and 12 months after surgery . Univariate and multivariate analysis were used to establish the association of risk factors and SSI . We studied clinical outcomes by a visual analog scale for pain and physical and mental component summaries ( PCS and MCS ) of the Medical Outcomes Survey 36-Item Short Form ( SF-36 )  . Results At 1 year , among 518 patients , we recorded 25 SSI events , with median occurrence at 16 days ( 25–75 % quartile : 13–44 days ) . Incidence of SSI was 3.2 % ( 95 % confidence interval [ 1.9–5.3 % ] ) at 1 month , 3.7 % ( 95 % [ 2.2–5.8 % ] ) at 3 months and 4.6 % ( 95 % CI [ 3–6.9 % ] ) at 12 months . On multivariate analysis , age , presence of diabetes and surgical duration were predictors of SSI ( p = 0.009 , p = 0.047 , and p = 0.015 respectively ) . At 12 months , infected and non-infected patients did not differ in pain ( p = 0.58 ) or SF-36 PCS ( p = 0.8 ) or MCS ( p = 0.68 ) . Conclusions In this large prospect i ve multicentre study in the context of spinal injury , we obtained an equivalent incidence rate and risk factors of SSI as found in the literature for elective spinal surgery Study Design . A retrospective review of data collected prospect ively by the American College of Surgeons National Surgical Quality Improvement Program ( ACS-NSQIP ) . Objective . The aim of this study was to investigate the association between preoperative hypoalbuminemia , a marker for malnutrition , and complications during the 30 days following posterior lumbar fusion surgery . Summary of Background Data . Malnutrition is a potentially modifiable risk factor that may contribute to complications following spinal surgery . Although prior studies have identified associations between malnutrition , delayed wound healing , and surgical site infection ( SSI ) , the evidence for such a relationship within spine surgery is mixed . Methods . Patients who underwent posterior lumbar spinal fusion of one to three levels as part of the ACS-NSQIP were identified . Patients without preoperative serum albumin concentration were excluded . Outcomes were compared between patients with and without hypoalbuminemia ( defined as serum albumin concentration < 3.5 g/dL ) . All comparisons were adjusted for baseline differences between population s. Results . Four thous and three hundred ten patients were included . The prevalence of hypoalbuminemia was 4.8 % . In comparison to patients with normal albumin concentration , patients with hypoalbuminemia had a higher risk for occurrence of wound dehiscence [ 1.5 % vs. 0.2 % , adjusted relative risk ( RR ) = 5.8 , P = 0.006 ] , SSI ( 5.4 % vs. 1.7 % , adjusted RR = 2.3 , P = 0.010 ) , and urinary tract infection ( 5.4 % vs. 1.5 % , adjusted RR = 2.5 , P = 0.005 ) . Similarly , patients with hypoalbuminemia had a higher risk for unplanned hospital readmission within 30 days of surgery ( 11.7 % vs. 5.4 % , RR = 1.8 , P < 0.001 ) . Finally , patients with hypoalbuminemia had a longer mean inpatient stay ( 5.2 vs. 3.7 days , RR = 1.2 , P < 0.001 ) . Conclusion . The present study suggests that malnutrition is an independent risk factor for infectious and wound complications following posterior lumbar fusion . Malnutrition was also associated with an increased length of stay and readmission . Future studies should evaluate methods of correcting malnutrition before lumbar spinal surgery . Such efforts have the potential to meaningfully decrease the rates of adverse events following this procedure . Level of Evidence : BACKGROUND CONTEXT The impact of surgical site infection ( SSI )  is substantial . Although previous study has determined relative risk and odds ratio ( OR ) values to quantify risk factors , these values may be difficult to translate to the patient during counseling of surgical options . Ideally , a model that predicts absolute risk of SSI , rather than relative risk or OR values , would greatly enhance the discussion of safety of spine surgery . To date , there is no risk stratification model that specifically predicts the risk of medical complication . PURPOSE The purpose of this study was to create and vali date a predictive model for the risk of SSI after spine surgery . STUDY DESIGN This study performs a multivariate analysis of SSI  after spine surgery using a large prospect i ve surgical registry . Using the results of this analysis , this study will then create and vali date a predictive model for SSI after spine surgery . PATIENT SAMPLE The patient sample is from a high- quality surgical registry from our two institutions with prospect ively collected , detailed demographic , comorbidity , and complication data . OUTCOME MEASURES An SSI that required return to the operating room for surgical debridement . MATERIAL S AND METHODS Using a prospect ively collected surgical registry of more than 1,532 patients with extensive demographic , comorbidity , surgical , and complication details recorded for 2 years after the surgery , we identified several risk factors for SSI after multivariate analysis . Using the beta coefficients from those regression analyses , we created a model to predict the occurrence of SSI after spine surgery . We split our data into two subsets for internal and cross-validation of our model . We created a predictive model based on our beta coefficients from our multivariate analysis . RESULTS The final predictive model for SSI had a receiver-operator curve characteristic of 0.72 , considered to be a fair measure . The final model has been uploaded for use on SpineSage.com . CONCLUSIONS We present a vali date d model for predicting SSI after spine surgery . The value in this model is that it gives the user an absolute percent likelihood of SSI after spine surgery based on the patient 's comorbidity profile and invasiveness of surgery . Patients are far more likely to underst and an absolute percentage , rather than relative risk and confidence interval values . A model such as this is of paramount importance in counseling patients and enhancing the safety of spine surgery . In addition , a tool such as this can be of great use particularly as health care trends toward pay for performance , quality metrics ( such as SSI ) , and risk adjustment . To facilitate the use of this model , we have created a Web site ( SpineSage.com ) where users can enter patient data to determine likelihood for SSI Study Design . Retrospective cohort study using data from the Nationwide Inpatient Sample administrative data from 1988 through 2003 . Objective . To examine perioperative morbidity and mortality for patients with and without diabetes mellitus following lumbar spinal fusion . Summary of Background Data . Diabetes has been associated with worse outcomes in a variety of orthopedic procedures including spinal surgery . There is limited evidence that diabetic patients have more complications following lumbar fusion with little published data to support this conclusion . Methods . Data from 197,461 patients who underwent lumbar fusion were included . Over 11,000 patients ( 5.6 % ) with a postoperative diagnosis of diabetes mellitus were identified . Selected variables were used for comparison of patients with and without diabetes . Bivariate statistical analyses compared postoperative complication rates while multivariate statistics were used to determine likelihood of complications with diabetes . Results . Bivariate analysis demonstrated that diabetes was significantly associated with postoperative infection , need for transfusion , pneumonia , in-hospital mortality , and nonroutine discharge ( P ≤ 0.001 ) . Adjusted multivariate regression analyses , however , suggested no difference in mortality although infection , transfusion , and nonroutine discharge continued to be highly significant ( P ≤ 0.002 ) . Significantly higher inflation adjusted total charges were also present with patients with diabetes as well as increased lengths of stay ( P < 0.001 ) . Conclusion . This nationally representative study of in patients in the United States provides evidence that diabetes is associated with increased risk for postoperative complications , nonroutine discharge , increased total hospital charges , and length of stay following lumbar fusion . Prospect i ve studies to determine causality as well as the potential impact of diabetes control on these variables have not yet been done BACKGROUND CONTEXT Surgical site infection ( SSI ) is one of the most serious complications of spine surgery . Its predisposing factors , especially in routine surgeries , are less reported . However , a number of patient- and procedure-related risk factors could be avoided or at least determined preoperatively . Moreover , the patient-specific risk for SSI could be estimated before the elective surgery . PURPOSE The aim of the present study was to analyze the preoperatively determinable risk factors for SSI in patients who require elective routine surgery related to lumbar disc degeneration and to build a multivariable model for the individual risk prediction . STUDY DESIGN Analysis of prospect ively collected st and ardized clinical data and the validation of the results on an independent prospect i ve cohort were performed . PATIENT SAMPLE One thous and thirty ( N=1,030 ) patients were included in the study . All subjects underwent primary lumbar single- or two-level decompression , microdiscectomy , or instrumented fusion .  OUTCOME MEASURES Occurrence of an SSI defined according to the current Centers for Disease Control and Prevention guidelines that required surgical or nonsurgical therapy . METHODS The effect of preoperative patient characteristics , comorbidities , disease history , and invasiveness of the elective surgery on the risk of SSI was determined in uni- and multivariate logistic regression models in the test cohort ( N=723 ) . The performance of the final multivariable regression model was assessed by measuring its discriminative ability ( c-index ) in receiver operating characteristic analysis . Performance of the multivariable risk estimation model was tested on the validation ( N=307 ) cohort . RESULTS The prevalence of SSI was 3.5 % and 3.9 % in the test and in the validation cohorts , respectively . The final multivariable regression model predictive ( p=.003 ) for SSI contained the patient 's age , body mass index ( BMI ) , and the presence of 5 comorbidities , such as diabetes , ischemic heart disease , arrhythmia , chronic liver disease , and autoimmune disease as risk factors . The c-index of the model was 0.71 , showing good discriminative ability , and it was confirmed by the data of the independent validation cohort ( c=0.72 ) . CONCLUSIONS Predisposing factors for SSI were older age , higher BMI , and the presence of certain comorbidities in the present study . The cumulative number of risk factors significantly associated with the increasing risk for an SSI ( p<.0001 ) . Our model needs further validation but it may be used for individual risk assessment and reduction in the future BACKGROUND CONTEXT The impact of patient factors and medical comorbidities on the risk of mortality and complications after  spinal arthrodesis  has not been well described . Prior works have been limited by small sample size , single center data , or the inability to be broadly generalized . PURPOSE To determine if there is an association between the patient demographic factors , comorbidities , nutritional status , and surgical characteristics and the occurrence of mortality and complications after spinal arthrodesis . STUDY DESIGN Retrospective review of prospect ively collected data in the National Surgical Quality Improvement Program ( NSQIP ) . PATIENT SAMPLE Patients who underwent spinal arthrodesis and had data registered with the NSQIP between 2005 and 2010 . OUTCOME MEASURES Primary outcomes were death or any complication after  spinal arthrodesis . Secondary measures were the development of a specific complication , including wound infection , thromboembolic disease , or cardiac arrest/myocardial infa rct ion . METHODS The data set of the NSQIP from 2005 to 2010 was queried to identify all patients who underwent spinal arthrodesis .  Demographic information , body mass index ( BMI ) , medical comorbidities , arthrodesis procedure , operative time , American Society of Anesthesiologists ( ASA ) classification , and preoperative albumin were recorded for all patients identified . Mortality , the development of postoperative complications , and the presence of specific complications were also abstract ed . Risk factors for mortality and complications were initially evaluated using chi-square and univariate logistic regression analyses . The risk factors that maintained p values less than .2 in univariate analysis were then combined in a multivariate fashion that identified significant , independent , predictors of mortality and complications while controlling for other factors present in the model . Sensitivity analysis was also performed , discriminating between the impact of risk factors on major and minor complications and the relative contribution to overall risk of morbidity . Multivariate analysis result ed in odds ratios ( ORs ) with 95 % confidence intervals ( CIs ) for each risk factor . Only those predictors with ORs and 95 % CI exclusive of 1.0 and p values less than .05 were considered statistically significant . RESULTS In all , 5,887 patients who underwent spinal arthrodesis were identified . The average age of patients was 55.9 ( ±14.5 ) years . Twenty-five ( 0.42 % ) patients died after surgery , whereas 608 ( 10 % ) sustained a complication . Wound infection was the most common specific complication occurring in 2 % of the cohort . Age ( p=.03 ) and pulmonary conditions ( p=.002 ) were found to have a significant association with the risk of mortality . Age exceeding 80 years was found to carry the highest risk of mortality . Age , pulmonary conditions , BMI , history of infection , ASA classification more than 2 , neurologic conditions , resident ( i.e. , trainee ) involvement , and procedural times exceeding 309 minutes increased the risk of complications . Body mass index , ASA classification more than 2 , resident involvement , and procedural times exceeding 309 minutes were associated with the risk of infection . Although limited to univariate analysis , serum albumin 3.5 g/dL or less increased the risk of mortality , complications , wound infection , and thromboembolic disease . The OR for postoperative mortality among patients with albumin 3.5 g/dL or less was 13.8 ( 95 % CI , 4.6 - 41.6 ; p<.001 ) . CONCLUSIONS Several factors , including patients ' age , BMI , ASA classification more than 2 , pulmonary conditions , procedural times , and nutritional status likely influence the risk of postoperative morbidity to varying degrees . The risk factors identified here may be more generalizable to the American population as a whole because of the design and methodology of the NSQIP in comparison with previously published studies Study Design . We conducted a retrospective , case control study on patients undergoing surgery for spinal tumors . Objective . Our aim was to determine the incidence and to identify risk factors for surgical site infections ( SSIs ) in patients undergoing surgery for spinal tumors . Summary of Background Data . SSIs after spinal tumor surgery may be particularly devastating as they may add to substantial surgical morbidity and may further exacerbate already existing neurologic deficits . Incidence and risk factors predisposing to SSIs in patients undergoing surgery for spinal tumors are not well studied yet . Methods . Between January 1995 and February 2008 , 971 procedures for spinal tumors were performed on 739 patients . Excluding sacral tumors from the current study , 895 procedures on 678 patients were review ed to identify those cases with SSIs . Furthermore , 65 infected cases and a r and omly selected subset of 162 controls were analyzed by logistic regression modeling to identify the risk factors associated with SSIs . Results . There were 678 patients that were included in this study with 364 men ( 54 % ) and 314 women ( 46 % ) , with an average age of 47.2 year . Sixty-five patients who developed SSIs underwent a total of 162 procedures including 78 procedures for wound debridement and washout . The incidence of SSIs was 8.89 % for primary nonbony spinal tumors , 9.5 % for metastatic spinal tumors , and 13.7 % for primary bony spinal tumors . Staphylococcus aureus was the most commonly isolated organism ( n = 22 of 65 , 33 % ) . In the multivariate logistic regression model , previous spinal surgeries , complex plastic closures , increasing number of comorbidities , presence of a hospital acquired infection at the time of a previous surgery , and increasing duration of hospital stay during primary surgery were significantly associated with increased likelihood of developing postoperative SSIs . Conclusion . Surgery for spine tumors appears to be associated with a higher incidence of SSI than nontumor spine surgery . Identification of perioperative risk factors will help delineate this subset of patients with high risk for developing SSIs thus potentially allowing perioperative modification for such factors , which may lead to an overall better clinical outcome and patient satisfaction Study Design . Prospect i ve cohort study . Objective . To create and vali date an index describing the extent of spine surgical intervention to allow fair comparisons of complication rates among patients treated by different surgeons , devices , or hospitals . Summary of Background Data . Safety comparisons in spine surgery are limited by lack of methods that adjust for important variations in the surgical “ case-mix . ” Among other factors , the magnitude of an operation is likely to have a substantial influence on the likelihood of complications . Methods . We created a spine surgery invasiveness index defined as the sum , across all vertebral levels , of 6 possible interventions on each operated vertebra : anterior decompression , anterior fusion , anterior instrumentation , posterior decompression , posterior fusion , and posterior instrumentation . We assessed the validity of this index by examining its association with blood loss and surgery duration in 1723 spine surgeries , adjusting for important factors including age , gender , body mass index , diagnosis , neurologic deficit , revision surgery , and vertebral level of surgery . Results . Blood loss increased by 11.5 % and surgery duration increased by 12.8 minutes for each unit increase in the invasiveness index . The invasiveness index explained 44 % of the variation in blood loss and 52 % of the variation in surgery duration . For specific surgical components , blood loss increased by 9.4 % and surgery duration by 11.4 minutes for each vertebral level of anterior decompression , 19.4 % and 33.8 minutes for each segment of anterior instrumentation , 12.9 % and 22.7 minutes for each level of posterior decompression , and 25.1 % and 18.8 minutes for each segment of posterior instrumentation . Conclusion . An “ invasiveness ” index based on the number of vertebrae decompressed , fused , or instrumented showed the expected associations with both blood loss and surgery duration . This quantitative description of surgery invasiveness may be useful to adjust for surgical variations when making safety comparisons in spine surgery BACKGROUND CONTEXT The incidence of surgical site infection ( SSI ) following posterior cervical surgery has been reported as high as 18 % in the literature . Few large studies have specifically examined posterior cervical procedures . PURPOSE The study aims to examine the incidence , timing , and risk factors for SSI following posterior cervical surgery . DESIGN This is a retrospective cohort study of prospect ively collected data in a national surgical outcomes data base . PATIENT SAMPLE The sample includes patients who underwent posterior cervical spine surgery between 2005 and 2012 identified in the American College of Surgeons National Surgical Quality Improvement Project ( ACS NSQIP ) Participant Use Data File . OUTCOME MEASURES The 30-day rate of postoperative SSI , timing of diagnosis , and associated risk factors were determined . METHODS The ACS NSQIP was used to identify 5,441 patients who underwent posterior cervical spine surgery by Current Procedural Terminology codes from 2005 to 2012 . Thirty-day readmission data were obtained for 2011 - 2012 . The incidence and timing of SSI were determined . Multivariable logistic regression analysis was then performed to identify significant risk factors . RESULTS Of the 5,441 patients identified as having undergone posterior cervical surgery , 3,724 had a posterior cervical decompression , 1,310 had a posterior cervical fusion , and 407 underwent cervical laminoplasty .  Surgical site infection within 30 days was identified in 160 patients ( 2.94 % ) , with 80 of those cases being superficial SSI . There was no significant difference in SSI rate among the three procedure groups . The average time for diagnosis of SSI was over 2 weeks . In 2011 - 2012 , 36.9 % of patients with SSI were readmitted within 30 days . Several significant predictors of SSI were identified in univariate analysis , including body mass index ( BMI ) > 35 , chronic steroid use , albumin <3 , hematocrit <33 , platelets < 100 , higher American Society of Anesthesiologists class , longer operative time , and longer hospital admission . Independent risk factors , including BMI > 35 ( odds ratio [OR]=1.78 , p=.003 ) , chronic steroid use ( OR=1.73 , p=.049 ) , and operative time > 197 minutes ( OR=2.08 , p=.005 ) , were identified in multivariable analysis . CONCLUSIONS Optimization of preoperative nutritional status , serum blood cell counts , and operative efficiency may lead to a reduction in SSI rates . Obese patients and patients on chronic steroid therapy should be counseled on elevated SSI risk Study Design . The Spine End Results Registry ( 2003–2004 ) is a registry of prospect ively collected data of all patients undergoing spinal surgery at the University of Washington Medical Center and Harborview Medical Center . Insurance data were prospect ively collected and used in multivariate analysis to determine risk of perioperative complications . Objective . Given the negative financial impact of surgical site infections ( SSIs ) and the higher overall complication rates of patients with a Medicaid payer status , we hypothesized that a Medicaid payer status would have a significantly higher SSI rate . Summary of Background Data . The medical literature demonstrates lesser outcomes and increased complication rates in patients who have public insurance than those who have private insurance . No one has shown that patients with a Medicaid payer status compared with Medicare and privately insured patients have a significantly increased SSI rate for spine surgery . Methods . The prospect ively collected Spine End Results Registry provided data for analysis . SSI was defined as treatment requiring operative debridement . Demographic , social , medical , and the surgical severity index risk factors were assessed against the exposure of payer status for the surgical procedure . Results . The population included Medicare ( N = 354 ) , Medicaid ( N = 334 ) , the Veterans ' Administration ( N = 39 ) , private insurers ( N = 603 ) , and self-pay ( N = 42 ) . Those patients whose insurer was Medicaid had a 2.06 odds ( 95 % confidence interval : 1.19–3.58 , P = 0.01 ) of having a SSI compared with the privately insured . Conclusion . The study highlights the increased cost of spine surgical procedures for patients with a Medicaid payer status with the passage of the Patient Protection and Affordable Care Act of 2010 . The Patient Protection and Affordable Care Act of 2010 provisions could cause a reduction in reimbursement to the hospital for taking care of patients with Medicaid insurance due to their higher complication rates and higher costs . This very issue could inadvertently lead to access limitations . Level of Evidence : Study Design . Prospect i ve analysis of 600 extreme lateral interbody fusion ( XLIF ) approach procedures  for intraoperative and perioperative complications . Objective . To delineate and describe complications in a large , prospect i ve series of minimally invasive lateral lumbar fusion procedures ( XLIF ) . Summary of Background Data . While some small series of lateral lumbar fusion have discussed complications , no results from large studies have been reported . Methods . A total of 600 patients were treated with a lateral approach to fusion ( XLIF ) for degenerative spinal conditions . Data were collected prospect ively on all patients and analyzed for demographic , diagnostic , and hospitalization information to identify operative and early postoperative complications . Documented complication types and rates in this large series were compared with smaller prior reports on lateral approach fusions , as well as other minimally invasive ( mini-anterior lumbar interbody fusion and minimally invasive surgical [ MIS ] transforaminal lumbar interbody fusion ) and more traditional fusion approaches ( posterior intertransverse fusion , anterior lumbar interbody fusion , posterior lumbar interbody fusion , transforaminal lumbar interbody fusion ) . Results . Seven hundred forty-one levels were treated , 80.8 % single level , 15.0 % 2 level , 4.0 % 3 level , 0.2 % 4 level ; 59.3 % , including the L4 to L5 levels . A total of 99.2 % included supplemental internal fixation ; 83.2 % included pedicle screw fixation ( predominantly unilateral ) . Hemoglobin change from pre- to postoperation averaged 1.38 . Hospital stay averaged 1.21 days . The overall incidence of perioperative complications ( intraoperation and out to 6 weeks postoperation ) was 6.2 % : 9 ( 1.5 % ) in-hospital surgery-related events , 17 ( 2.8 % ) in-hospital medical events , 6 ( 1.0 % ) out-of-hospital surgery-related events , and 5 ( 0.8 % ) out-of-hospital medical events . There were no wound infections , no vascular injuries , no intraoperative visceral injuries , and 4 ( 0.7 % ) transient postoperative neurologic deficits . Eleven events ( 1.8 % ) result ed in additional procedures /reoperation . Conclusions . Compared with traditional open approaches , the MIS lateral approach to fusion by using the XLIF technique result ed in a lower incidence of infection , visceral and neurologic injury , and transfusion as well as markedly shorter hospitalization . Complications in MIS XLIF compare favorably with those from other MIS fusion procedures ; duration of hospitalization is shorter than with any previously reported technique
target: 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 .
background: Objective : To perform a review of SSI risk factors and more specifically , categorize them into patient and surgical factors .