human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: 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 
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agent
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 .
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: 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 
    Output:
    