Risk factors for not reaching minimal clinically important difference at 90 days and 1 year after elective lumbar spine surgery: a cohort study.

OBJECTIVE: Patient-perceived functional improvement is a core metric in lumbar surgery for degenerative disease. It is important to identify both modifiable and nonmodifiable risk factors that can be evaluated and possibly optimized prior to elective surgery. This case-control study was designed to study risk factors for not achieving the minimal clinically important difference (MCID) in Patient-Reported Outcomes Measurement Information System Function 4-item Short Form (PROMIS PF) score. METHODS: The authors queried the Michigan Spine Surgery Improvement Collaborative database to identify patients who underwent elective lumbar surgical procedures with PROMIS PF scores. Cases were divided into two cohorts based on whether patients achieved MCID at 90 days and 1 year after surgery. Patient characteristics and operative details were analyzed as potential risk factors. RESULTS: The authors captured 10,922 patients for 90-day follow-up and 4453 patients (40.8%) did not reach MCID. At the 1-year follow-up period, 7780 patients were identified and 2941 patients (37.8%) did not achieve MCID. The significant demographic characteristic-adjusted relative risks (RRs) for both groups (RR 90 day, RR 1 year) included the following: symptom duration > 1 year (1.34, 1.41); previous spine surgery (1.25, 1.30); African American descent (1.25, 1.20); chronic opiate use (1.23, 1.25); and less than high school education (1.20, 1.34). Independent ambulatory status (0.83, 0.88) and private insurance (0.91, 0.85) were associated with higher likelihood of reaching MCID at 90 days and 1 year, respectively. CONCLUSIONS: Several key unique demographic risk factors were identified in this cohort study that precluded optimal postoperative functional outcomes after elective lumbar spine surgery. With this information, appropriate preoperative counseling can be administered to assist in shaping patient expectations.

The Potential Negative Effects of Smoking on Cervical and Lumbar Surgery Beyond Pseudarthrosis: A Michigan Spine Surgery Improvement Collaborative Study.

OBJECTIVE: To review the Michigan Spine Surgery Improvement Collaborative registry to investigate the long-term associations between current smoking status and outcomes after elective cervical and lumbar spine surgery. METHODS: Using the Michigan Spine Surgery Improvement Collaborative, we captured all cases from January 1, 2017, to November 21, 2020, with outcomes data available; 19,251 lumbar cases and 7936 cervical cases were included. Multivariate regression analyses were performed to assess the relationship of smoking with the clinical outcomes. RESULTS: Current smoking status was associated with lower urinary retention and satisfaction for patients after lumbar surgery and was associated with less likelihood of achieving minimal clinically important difference in primary outcome measures including Patient-Reported Outcomes Measurement Information System, back pain, leg pain, and EuroQol-5D at 90 days and 1 year after surgery. Current smokers were also less likely to return to work at 90 days and 1 year after surgery. Among patients who underwent cervical surgery, current smokers were less likely to have urinary retention and dysphagia postoperatively. They were less likely to be satisfied with the surgery outcome at 1 year. Current smoking was associated with lower likelihood of achieving minimal clinically important difference in Patient-Reported Outcomes Measurement Information System, neck pain, arm pain, and EuroQol-5D at various time points. There was no difference in return-to-work status. CONCLUSIONS: Our analysis suggests that smoking is negatively associated with functional improvement, patient satisfaction, and return-to-work after elective spine surgery.

Postoperative opioid prescription and patient-reported outcomes after elective spine surgery: a Michigan Spine Surgery Improvement Collaborative study.

OBJECTIVE: This study was designed to assess how postoperative opioid prescription dosage could affect patient-reported outcomes after elective spine surgery. METHODS: Patients enrolled in the Michigan Spine Surgery Improvement Collaborative (MSSIC) from January 2020 to September 2021 were included in this study. Opioid prescriptions at discharge were converted to total morphine milligram equivalents (MME). A reference value of 225 MME per week was used as a cutoff. Patients were divided into two cohorts based on prescribed total MME: ≤ 225 MME and > 225 MME. Primary outcomes included patient satisfaction, return to work status after surgery, and whether improvement of the minimal clinically important difference (MCID) of the Patient-Reported Outcomes Measurement Information System 4-question short form for physical function (PROMIS PF) and EQ-5D was met. Generalized estimated equations were used for multivariate analysis. RESULTS: Regression analysis revealed that patients who had postoperative opioids prescribed with > 225 MME were less likely to be satisfied with surgery (adjusted OR [aOR] 0.81) and achieve PROMIS PF MCID (aOR 0.88). They were also more likely to be opioid dependent at 90 days after elective spine surgery (aOR 1.56). CONCLUSIONS: The opioid epidemic is a serious threat to national public health, and spine surgeons must practice conscientious postoperative opioid prescribing to achieve adequate pain control. The authors' analysis illustrates that a postoperative opioid prescription of 225 MME or less is associated with improved patient satisfaction, greater improvement in physical function, and decreased opioid dependence compared with those who had > 225 MME prescribed.

Validation of the Benefits of Ambulation Within 8 Hours of Elective Cervical and Lumbar Surgery: A Michigan Spine Surgery Improvement Collaborative Study.

BACKGROUND: Early ambulation is considered a key element to Enhanced Recovery After Surgery protocol after spine surgery. OBJECTIVE: To investigate whether ambulation less than 8 hours after elective spine surgery is associated with improved outcome. METHODS: The Michigan Spine Surgery Improvement Collaborative database was queried to track all elective cervical and lumbar spine surgery between July 2018 and April 2021. In total, 7647 cervical and 17 616 lumbar cases were divided into 3 cohorts based on time to ambulate after surgery: (1) <8 hours, (2) 8 to 24 hours, and (3) >24 hours. RESULTS: For cervical cases, patients who ambulated 8 to 24 hours (adjusted odds ratio [aOR] 1.38; 95% CI 1.11-1.70; P = .003) and >24 hours (aOR 2.20; 95% CI 1.20-4.03; P = .011) after surgery had higher complication rate than those who ambulated within 8 hours of surgery. Similar findings were noted for lumbar cases with patients who ambulated 8 to 24 hours (aOR 1.31; 95% CI 1.12-1.54; P < .001) and >24 hours (aOR 1.96; 95% CI 1.50-2.56; P < .001) after surgery having significantly higher complication rate than those ambulated <8 hours after surgery. Analysis of secondary outcomes for cervical cases demonstrated that <8-hour ambulation was associated with home discharge, shorter hospital stay, lower 90-day readmission, and lower urinary retention rate. For lumbar cases, <8-hour ambulation was associated with shorter hospital stay, satisfaction with surgery, lower 30-day readmission, home discharge, and lower urinary retention rate. CONCLUSION: Ambulation within 8 hours after surgery is associated with significant improved outcome after elective cervical and lumbar spine surgery.

A Matched Cohort Analysis of Drain Usage in Elective Anterior Cervical Discectomy and Fusion: A Michigan Spine Surgery Improvement Collaborative (MSSIC) Study.

STUDY DESIGN: This is a retrospective, cohort analysis of multi-institutional database. OBJECTIVE: This study was designed to analyze the impact of drain use following elective anterior cervical discectomy and fusion (ACDF) surgeries. SUMMARY OF BACKGROUND DATA: After ACDF, a drain is often placed to prevent postoperative hematoma. However, there has been no high quality evidence to support its use with ACDF despite the theoretical benefits and risks of drain placement. METHODS: The Michigan Spine Surgery Improvement Collaborative database was queried to identify all patients undergoing elective ACDF between February 2014 and October 2019. Cases were divided into two cohorts based on drain use. Propensity-score matching was utilized to adjust for inherent differences between the two cohorts. Measured outcomes included surgical site hematoma, length of stay, surgical site infection, dysphagia, home discharge, readmission within 30 days, and unplanned reoperation. RESULTS: We identified 7943 patients during the study period. Propensity-score matching yielded 3206 pairs. On univariate analysis of matched cohorts, there were no differences in rate of postoperative hematoma requiring either return to OR or readmission. We noted patients with drains had a higher rate of dysphagia (4.6% vs. 6.3%; P = 0.003) and had longer hospital stay (P < 0.001). On multivariate analysis, drain use was associated with significantly increased length of stay (relative risk 1.23, 95% confidence interval [CI] 1.13-1.34; P < 0.001). There were no significant differences in other outcomes measured. CONCLUSION: Our analysis demonstrated that drain use is associated with significant longer hospital stay.Level of Evidence: 3.

Analysis of Factors Associated with Return-to-Work After Lumbar Surgery up to 2-Years Follow-up: A Michigan Spine Surgery Improvement Collaborative (MSSIC) Study.

STUDY DESIGN: Michigan Spine Surgery Improvement Collaborative (MSSIC) prospectively collects data on all patients undergoing operations for degenerative and/or deformity indications. OBJECTIVE: We aimed to identify which factors are significantly associated with return-to-work after lumbar surgery at long-term follow-up. SUMMARY OF BACKGROUND DATA: Prior publications have created a clinically relevant predictive model for return-to-work, wherein education, gender, race, comorbidities, and preoperative symptoms increased likelihood of return-to-work at 3 months after lumbar surgery. We sought to determine if these trends 1) persisted at 1 year and 2 years postoperatively; or 2) differed among preoperatively employed versus unemployed patients. METHODS: MSSIC was queried for all patients undergoing lumbar operations (2014-2019). All patients intended to return-to-work postoperatively. Patients were followed for up to 2 years postoperatively. Measures of association were calculated with multivariable generalized estimating equations. RESULTS: Return-to-work increased from 63% (3542/5591) at 90 days postoperatively to 75% (3143/4147) at 1 year and 74% (2133/2866) at 2 years postoperatively. Following generalized estimating equations, neither clinical nor surgical variables predicted return-to-work at all three time intervals: 90 days, 1 year, and 2 years postoperatively. Only socioeconomic factors reached statistical significance at all follow-up points. Preoperative employment followed by insurance status had the greatest associations with return-to-work. In a subanalysis of patients who were preoperatively employed, insurance was the only factor with significant associations with return-to-work at all three follow-up intervals. The return-to-work rates among unemployed patients at baseline increased from 29% (455/1100) at 90 days, 44% (495/608) at 1 year, and 46% (366/426) at 2 years postoperatively. The only two significant factors associated with return-to-work at all three follow-up intervals were Medicaid, as compared with private insurance, and male gender. CONCLUSION: In patients inquiring about long-term return-to-work after lumbar surgery, insurance status represents the important determinant of employment status.Level of Evidence: 2.

Work relative value units and perioperative outcomes in patients undergoing brain tumor surgery.

The work relative value unit (wRVU) is a commonly cited surrogate for surgical complexity; however, it is highly susceptible to subjective interpretation and external forces. Our objective was to evaluate whether wRVU is associated with perioperative outcomes, including complications, after brain tumor surgery. The 2006-2014 American College of Surgeons National Surgical Quality Improvement Program database was queried to identify patients ≥ 18 years who underwent brain tumor resection. Patients were categorized into approximate quintiles based on total wRVU. The relationship between wRVU and several perioperative outcomes was assessed with univariate and multivariate analyses. Subgroup analyses were performed using a Current Procedural Terminology code common to all wRVU groups. The 16,884 patients were categorized into wRVU ranges 0-30.83 (4664 patients), 30.84-34.58 (2548 patients), 34.59-38.04 (3147 patients), 38.05-45.38 (3173 patients), and ≥ 45.39 (3352 patients). In multivariate logistic regression analysis, increasing wRVU did not predict more 30-day postoperative complications, except respiratory complications and need for blood transfusion. Linear regression analysis showed that wRVU was poorly correlated with operative duration and length of stay. On multivariate analysis of the craniectomy subgroup, wRVU was not associated with overall or respiratory complications. The highest wRVU group was still associated with greater risk of requiring blood transfusion (OR 3.01, p < 0.001). Increasing wRVU generally did not correlate with 30 days postoperative complications in patients undergoing any surgery for brain tumor resection; however, the highest wRVU groups may be associated with greater risk of respiratory complications and need for transfusion. These finding suggests that wRVU may be a poor surrogate for case complexity.

The role of postoperative antibiotic duration on surgical site infection after lumbar surgery.

OBJECTIVE: Despite a general consensus regarding the administration of preoperative antibiotics, poorly defined comparison groups and underpowered studies prevent clear guidelines for postoperative antibiotics. Utilizing a data set tailored specifically to spine surgery outcomes, in this clinical study the authors aimed to determine whether there is a role for postoperative antibiotics in the prevention of surgical site infection (SSI). METHODS: The Michigan Spine Surgery Improvement Collaborative registry was queried for all lumbar operations performed for degenerative spinal pathologies over a 5-year period from 2014 to 2019. Preoperative prophylactic antibiotics were administered for all surgical procedures. The study population was divided into three cohorts: no postoperative antibiotics, postoperative antibiotics ≤ 24 hours, and postoperative antibiotics > 24 hours. This categorization was intended to determine 1) whether postoperative antibiotics are helpful and 2) the appropriate duration of postoperative antibiotics. First, multivariable analysis with generalized estimating equations (GEEs) was used to determine the association between antibiotic duration and all-type SSI with adjusted odds ratios; second, a three-tiered outcome-no SSI, superficial SSI, and deep SSI-was calculated with multivariable multinomial logistical GEE analysis. RESULTS: Among 37,161 patients, the postoperative antibiotics > 24 hours cohort had more men with older average age, greater body mass index, and greater comorbidity burden. The postoperative antibiotics > 24 hours cohort had a 3% rate of SSI, which was significantly higher than the 2% rate of SSI of the other two cohorts (p = 0.004). On multivariable GEE analysis, neither postoperative antibiotics > 24 hours nor postoperative antibiotics ≤ 24 hours, as compared with no postoperative antibiotics, was associated with a lower rate of all-type postoperative SSIs. On multivariable multinomial logistical GEE analysis, neither postoperative antibiotics ≤ 24 hours nor postoperative antibiotics > 24 hours was associated with rate of superficial SSI, as compared with no antibiotic use at all. The odds of deep SSI decreased by 45% with postoperative antibiotics ≤ 24 hours (p = 0.002) and by 40% with postoperative antibiotics > 24 hours (p = 0.008). CONCLUSIONS: Although the incidence of all-type SSI was highest in the antibiotics > 24 hours cohort, which also had the highest proportions of risk factors, duration of antibiotics failed to predict all-type SSI. On multinomial subanalysis, administration of postoperative antibiotics for both ≤ 24 hours and > 24 hours was associated with decreased risk of only deep SSI but not superficial SSI. Spine surgeons can safely consider antibiotics for 24 hours, which is equally as effective as long-term administration for prophylaxis against deep SSI.

Minimally Invasive Posterior Cervical Discectomy: 2-Dimensional Operative Video.

Minimally invasive posterior cervical microdiscectomy is an appropriate surgical approach for patients with foraminal stenosis from herniated disc with radicular symptoms that is not responsive to conservative management. While anterior cervical discectomy and fusion (ACDF) or arthroplasty is increasingly utilized to treat herniated disc, a posterior approach eliminates the risk of potential approach related injuries to the esophagus, carotid artery, or recurrent laryngeal nerve. Additional benefits of posterior decompression include avoidance of instrumentation, which represents an increased healthcare cost, as well as potential long-term risks of adjacent-level pathologies or device failures. A traditional open posterior cervical approach has the potential to cause significant postoperative pain due to dissection of the paraspinal musculature and the potential for disrupting the posterior tension band with inadvertent injury to the interspinous ligaments. Such disadvantages are reduced by utilizing the minimally invasive technique where a small tubular working channel is placed through a muscle splitting technique via a paramedian approach. This technique minimizes the need for muscle stripping, and thus decreases postoperative functional and structural disturbance. Discectomy in this case can also be safely performed with minimal retraction at the axilla of the nerve root. Additionally, this approach can be utilized in an ambulatory setting, which coupled with the lack of any additional instrumentation helps contribute to the overall healthcare cost savings of such a procedure. This video describes how the minimally invasive posterior cervical discectomy can be effectively and safely performed in this illustrative case. The patient consented to the procedure and publication.

Preoperative HbA1c > 8% Is Associated With Poor Outcomes in Lumbar Spine Surgery: A Michigan Spine Surgery Improvement Collaborative Study.

BACKGROUND: Preoperative hemoglobin A1c (HbA1c) is a useful screening tool since a significant portion of diabetic patients in the United States are undiagnosed and the prevalence of diabetes continues to increase. However, there is a paucity of literature analyzing comprehensive association between HbA1c and postoperative outcome in lumbar spine surgery. OBJECTIVE: To assess the prognostic value of preoperative HbA1c > 8% in patients undergoing elective lumbar spine surgery. METHODS: The Michigan Spine Surgery Improvement Collaborative (MSSIC) database was queried to track all elective lumbar spine surgeries between January 2018 and December 2019. Cases were divided into 2 cohorts based on preoperative HbA1c level (≤8% and >8%). Measured outcomes include any complication, surgical site infection (SSI), readmission (RA) within 30 d (30RA) and 90 d (90RA) of index operation, patient satisfaction, and the percentage of patients who achieved minimum clinically important difference (MCID) using Patient-Reported Outcomes Measurement Information System. RESULTS: We captured 4778 patients in this study. Our multivariate analysis demonstrated that patients with HbA1c > 8% were more likely to experience postoperative complication (odds ratio [OR] 1.81, 95% CI 1.20-2.73; P = .005) and be readmitted within 90 d of index surgery (OR 1.66, 95% CI 1.08-2.54; P = .021). They also had longer hospital stay (OR 1.12, 95% CI 1.03-1.23; P = .009) and were less likely to achieve functional improvement after surgery (OR 0.64, 95% CI 0.44-0.92; P = .016). CONCLUSION: HbA1c > 8% is a reliable predictor of poor outcome in elective lumbar spine surgery. Clinicians should consider specialty consultation to optimize patients' glycemic control prior to surgery.

Disparities in outcomes after spine surgery: a Michigan Spine Surgery Improvement Collaborative study.

OBJECTIVE: Most studies on racial disparities in spine surgery lack data granularity to control for both comorbidities and self-assessment metrics. Analyses from large, multicenter surgical registries can provide an enhanced platform for understanding different factors that influence outcome. In this study, the authors aimed to determine the effects of race on outcomes after lumbar surgery, using patient-reported outcomes (PROs) in 3 areas: the North American Spine Society patient satisfaction index, the minimal clinically important difference (MCID) on the Oswestry Disability Index (ODI) for low-back pain, and return to work. METHODS: The Michigan Spine Surgery Improvement Collaborative was queried for all elective lumbar operations. Patient race/ethnicity was categorized as Caucasian, African American, and "other." Measures of association between race and PROs were calculated with generalized estimating equations (GEEs) to report adjusted risk ratios. RESULTS: The African American cohort consisted of a greater proportion of women with the highest comorbidity burden. Among the 7980 and 4222 patients followed up at 1 and 2 years postoperatively, respectively, African American patients experienced the lowest rates of satisfaction, MCID on ODI, and return to work. Following a GEE, African American race decreased the probability of satisfaction at both 1 and 2 years postoperatively. Race did not affect return to work or achieving MCID on the ODI. The variable of greatest association with all 3 PROs at both follow-up times was postoperative depression. CONCLUSIONS: While a complex myriad of socioeconomic factors interplay between race and surgical success, the authors identified modifiable risk factors, specifically depression, that may improve PROs among African American patients after elective lumbar spine surgery.

The influence of sagittal spinopelvic alignment on patient discharge disposition following minimally invasive lumbar interbody fusion.

BACKGROUND: The aim of this study was to investigate the changes to spinopelvic sagittal alignment following minimally invasive (MIS) lumbar interbody fusion, and the influence of such changes on postoperative discharge disposition. METHODS: The Michigan Spine Surgery Improvement Collaborative was queried for all patients who underwent transforaminal lumbar interbody fusion (TLIF)or lateral lumbar interbody fusion (LLIF) procedures for degenerative spine disease. Several spinopelvic sagittal alignment parameters were measured, including sagittal vertical axis (SVA), lumbar lordosis, pelvic tilt, pelvic incidence, and pelvic incidence-lumbar lordosis mismatch. Primary outcome measure-discharge to a rehabilitation facility-was expressed as adjusted odds ratio (ORadj) following a multivariable logistical regression. RESULTS: Of the 83 patients in the study population, 11 (13.2%) were discharged to a rehabilitation facility. Preoperative SVA was equivalent. Postoperative SVA increased to 8.0 cm in the discharge-to-rehabilitation division versus a decrease to 3.6 cm in the discharge-to-home division (P<0.001). The odds of discharge to a rehabilitation facility increased by 25% for every 1-cm increase in postoperative sagittal balance (ORadj =1.27, P=0.014). The strongest predictor of discharge to rehabilitation was increasing decade of life (ORadj =3.13, P=0.201). CONCLUSIONS: Correction of sagittal balance is associated with greater odds of discharge to home. These findings, coupled with the recognized implications of admission to a rehabilitation facility, will emphasize the importance of spine surgeons accounting for SVA into their surgical planning of MIS lumbar interbody fusions.

Comparison of 30-day outcome following anterior cervical discectomy and fusion with or without instrumentation for cervical spondylosis: A review of 2352 elective cases.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) is a commonly performed procedure to address cervical myeloradiculopathy. However, 30-day outcomes after additional plating/instrumentation are not very clear. METHODS: The authors reviewed The National Surgical Quality Improvement Program database to identify all elective ACDF cases with or without instrumentation for patients having cervical spondylosis with or without myelopathy from 2011 to 2013 using current procedural terminology and International Classification of Disease-9 codes. We identified 2352 cases and subdivided these into two cohorts based on instrumentation procedures (588 cases without instrumentation and 1764 cases with instrumentation). Baseline differences in two cohorts were adjusted by propensity score matching analysis, yielding well-matched 583 pairs. RESULTS: Following propensity matching, the authors observed no significant difference in 30-day complication rates (prematch, 2.4% vs. 2.4%; and postmatch, 2.4% vs. 1.7%), readmission (prematch, 4.1% vs. 3.2%; and postmatch, 3.9% vs. 3.3%), and reoperation (prematch 0.9% vs. 1.8%; and postmatch 0.9% vs. 1.5%). CONCLUSION: Our results demonstrate similar 30-day outcomes in both cohorts and suggest that instrumentation can be safely implemented in the setting of ACDF.

The impact of 5-aminolevulinic acid on extent of resection in newly diagnosed high grade gliomas: a systematic review and single institutional experience.

BACKGROUND: Glioma surgery at its nascency relied predominantly on visual and tactile feedback for the removal of grossly abnormal tissue. This technique has inherent limitations in delineating infiltrative tumor from normal brain, thus limiting the ability to achieve a gross total resection consistently. Since extent of resection (EOR) is consistently correlated with measures of survival, fluorescence-guided surgery shows promise in improving our ability to treat high-grade gliomas (HGG). 5-Aminolevulinic acid (5-ALA) is a prodrug preferentially metabolized by glioma cells that allows direct, real-time visualization of pathologic tissue through fluorescence under blue light. OBJECTIVE: To report the relationship between 5-ALA and EOR in newly diagnosed HGG. To report our institutional experience including nuances of workflow. METHODS: The authors performed a systematic review of the available literature between 1998 and 2018 to isolate studies addressing the impact of fluorescence-guided surgery with 5-ALA on the EOR in newly diagnosed HGG. Search strategy was in adherence to the preferred reporting items for systematic reviews and meta-analyses methodology. RESULTS: Out of 741 unique articles, eight fulfilled our strict inclusion criteria. Fluorescence-guided resection led to greater EOR in all studies, with six demonstrating statistical significance (p < 0.05). Two studies additionally demonstrated statistically significant increase in progression-free survival in the 5-ALA groups. CONCLUSIONS: 5-ALA has an unambiguously positive impact on improving EOR for newly diagnosed HGG. Since the nature of modern glioma surgery includes a complex arsenal of surgical adjuncts, 5-ALA is seldom examined in isolation and can be complemented by intraoperative MRI.

Clinching the cause: A review of foot drop secondary to lumbar degenerative diseases.

Foot drop is defined as weakness on dorsiflexion of the foot. The top two most common etiologies for foot drop include lumbar degenerative disease and common peroneal nerve injury. This review provides "updates" on understanding the lumbar etiologies of foot drop. Since the publication of "Preoperative motor strength and time to surgery are the most important predictors of improvement in foot drop due to degenerative lumbar disease" in the Journal of Neurological Sciences, three cohort studies have been published on spinal causes of foot drop. Classification, clinical features, diagnosis, and pathogenesis that may 'clinch' the cause of foot drop are discussed in the context of these recent publications.

Risk Factors for Postoperative Infections After Single-Level Lumbar Fusion Surgery.

STUDY DESIGN: Retrospective multivariate analysis of a prospectively collected, multicenter database. OBJECTIVE: To identify patient characteristics and perioperative risk factors associated with postoperative infectious complications after single-level lumbar fusion (SLLF) surgery. SUMMARY OF BACKGROUND DATA: Postoperative infection is a known complication after lumbar fusion. Risk factors for infectious complications after lumbar fusion have not been investigated using select set of SLLF procedures. METHODS: Patients who underwent SLLF between 2006 and 2011 were identified from the American College of Surgeons National Surgical Quality Improvement Program database. Multivariate logistic regression analyses were performed to identify pre- and intraoperative risk factors associated with postoperative infection. RESULTS: A total of 3353 patients were analyzed in this study. Overall, 173 (5.2%) patients experienced a postoperative infection, including 86 (2.6%) surgical site infections (SSIs) and 111 (3.3%) non-SSI infectious complications (pneumonia, urinary tract infection, sepsis/septic shock). Twenty-four (0.7%) patients experienced both SSI and non-SSI infectious complications. Postoperative SSI were associated with obesity (odds ratio [OR], 1.628; 95% confidence interval [CI], 1.042-2.544), American Society of Anesthesiologists class more than 2 (OR, 2.078; 95% CI, 1.309-3.299), and operative time more than 6 hours (OR, 2.573; 95% CI, 1.310-5.056). Risk factors for non-SSI infectious complications included age (60-69 yr; OR, 3.279; 95% CI, 1.541-6.980; and ≥70 yr; OR, 3.348; 95% CI, 1.519-7.378), female sex (OR, 1.791; 95% CI, 1.183-2.711), creatinine more than 1.5 mg/dL (OR, 2.400; 95% CI, 1.138-5.062), American Society of Anesthesiologists class more than 2 (OR, 1.835; 95% CI, 1.177-2.860), and operative time more than 6 hours (OR, 3.563; 95% CI, 2.082-6.097). CONCLUSION: Across a wide study population, we identified that obesity, advanced American Society of Anesthesiologists classification, and longer operative time were predictive of postoperative SSI. We also demonstrated that increased age, female sex, serum creatinine more than 1.5 mg/dL, and prolonged operative duration are associated with non-SSI infectious complications after SLLF. Continued efforts to elucidate and optimize perioperative risk factors are warranted to improve outcomes in patients requiring spinal fusion. LEVEL OF EVIDENCE: 3.