The Impact of Upper Cervical Spine Alignment on Patient-reported Outcome Measures in Anterior Cervical Decompression and Fusion.

STUDY DESIGN: This was a retrospective cohort study. OBJECTIVE: To determine the extent to which the upper cervical spine compensates for malalignment in the subaxial cervical spine, and how changes in upper cervical spine sagittal alignment affect patient-reported outcomes. SUMMARY OF BACKGROUND DATA: Previous research has investigated the relationship between clinical outcomes and radiographic parameters in the subaxial cervical spine following anterior cervical discectomy and fusion (ACDF). However, limited research exists regarding the upper cervical spine (occiput to C2), which accounts for up to 40% of neck movement and has been hypothesized to compensate for subaxial dysfunction. MATERIALS AND METHODS: Patients undergoing ACDF for cervical radiculopathy and/or myelopathy at a single center with minimum 1-year follow-up were included. Radiographic parameters including cervical sagittal vertical axis, C0 angle, C1 inclination angle, C2 slope, Occiput-C1 angle (Oc-C1 degrees), Oc-C2 degrees, Oc-C7 degrees, C1-C2 degrees, C1-C7 degrees, and C2-C7 degrees cervical lordosis (CL) were recorded preoperatively and postoperatively. Delta (Δ) values were calculated by subtracting preoperative values from postoperative values. Correlation analysis as well as multiple linear regression analysis was used to determine relationships between radiographic and clinical outcomes. Alpha was set at 0.05. RESULTS: A total of 264 patients were included (mean follow-up 20 mo). C2 slope significantly decreased for patients after surgery (Δ=-0.8, P =0.02), as did parameters of regional cervical lordosis (Oc-C7 degrees, C1-C7 degrees, and C2-C7 degrees; P <0.001, <0.001, and 0.01, respectively). Weak to moderate associations were observed between postoperative CL and C1 inclination ( r =-0.24, P <0.001), Oc-C1 degrees ( r =0.59, P <0.001), and C1-C2 degrees ( r =-0.23, P <0.001). Increased preoperative C1-C2 degrees and Oc-C2 degrees inversely correlated with preoperative SF-12 Mental Composite Score (MCS-12) scores ( r =-0.16, P =0.01 and r =-0.13, P =0.04). Cervical sagittal vertical axis was found to have weak but significant associations with Short Form-12 (SF-12) Physical Composite Score (PCS-12) ( r =-0.13, P =0.03) and MCS-12 ( r =0.12, P =0.05). CONCLUSION: No clinically significant relationship between upper cervical and subaxial cervical alignment was detected for patients undergoing ACDF for neurological symptoms. Upper cervical spine alignment was not found to be a significant predictor of patient-reported outcomes after ACDF. LEVEL OF EVIDENCE: Level III.

Stability in Direct Lateral vs Direct Anterior Total Hip Arthroplasty in the Context of Lumbar Spinal Fusion.

INTRODUCTION: Lumbar spinal fusion (LSF) may increase the risk of dislocation in patients who have undergone total hip arthroplasty (THA), especially when the LSF was done before the THA. Most publications evaluated patients who had undergone THA using a posterior approach to the hip, yet there are little data on the influence of other surgical approaches. The goal of this study was to evaluate the risk of THA dislocation with anterior supine-based surgical approaches to the hip in patients who have undergone surgical management of concurrent hip and spine pathology. METHODS: Patients older than 18 years who underwent an LSF and THA using a supine approach-either direct anterior (DA) or direct lateral (DL)-between 2000 and 2018 were identified. Only standard bearings (28-32-36-40 mm) were used. The dislocation rate was determined in this cohort. A subsequent analysis was conducted, stratifying patients based on the order in which they received the LSF or THA. RESULTS: A total of 582 surgical hip-spine patients were retrospectively identified and included in the cohort. Of total, 332 patients (57.0%) received an LSF before the THA; 250 (43.0%) had the fusion after a primary hip replacement. There were 143 patients (24.6%) in the DA group and 439 (75.4%) in the DL group. Overall, there were five dislocations (0.9%) in the entire cohort. CONCLUSIONS: In patients with simultaneous degenerative hip and lumbar spine pathology, anterior supine-based approaches demonstrate a low (<1%) risk of instability. Given the small number of total dislocation events (n = 5), additional analysis is warranted to assess the effect of different anterior approaches (DA versus DL) or timing of lumbar spinal surgery (before or after THA). LEVEL OF EVIDENCE: Level III.

The Role of Family-wise Error Rate in Determining Statistical Significance.

The threshold for statistical significance is determined by the maximum allowable probability of Type I error (α). For studies that test multiple hypotheses or make multiple comparisons, the probability of at least 1 Type I error (family-wise error rate; FWER) increases as the number of hypotheses/comparisons increase. It is generally best practice to set the acceptable threshold for FWER to be less than or equal to α. Bonferroni correction and Tukey honestly significant difference test are 2 of the more common methods to control for FWER. When doing exploratory analysis or evaluating secondary outcomes of a study, it may not be necessary or desirable to control for FWER, which reduces the power of the study. However, deciding to control for FWER should be decided during the design of the study.

Management of Acute Subaxial Trauma and Spinal Cord Injury in Professional Collision Athletes.

Sports-related acute cervical trauma and spinal cord injury (SCI) represent a rare but devastating potential complication of collision sport injuries. Currently, there is debate on appropriate management protocols and return-to-play guidelines in professional collision athletes following cervical trauma. While cervical muscle strains and sprains are among the most common injuries sustained by collision athletes, the life-changing effects of severe neurological sequelae (ie, quadriplegia and paraplegia) from fractures and SCIs require increased attention and care. Appropriate on-field management and subsequent transfer/workup at an experienced trauma/SCI center is necessary for optimal patient care, prevention of injury exacerbation, and improvement in outcomes. This review discusses the epidemiology, pathophysiology, clinical presentation, immediate/long-term management, and current return-to-play recommendations of athletes who suffer cervical trauma and SCI.

PEEK Versus Titanium Static Interbody Cages: A Comparison of 1-Year Clinical and Radiographic Outcomes for 1-Level TLIFs.

STUDY DESIGN: This was a retrospective cohort study. OBJECTIVE: This study evaluates the patient-reported Health Related Quality of Life outcomes and radiographic parameters of patients who underwent a single level transforaminal lumbar interbody fusion with either a polyetheretherketone (PEEK) or titanium interbody cage. SUMMARY OF BACKGROUND DATA: Spinal stenosis with instability is a common diagnosis that is often treated with interbody fusion, in particular transforaminal lumbar interbody fusion. Titanium and PEEK interbody cage properties have been extensively studied to understand their effect on fusion rates and subsidence. MATERIALS AND METHODS: A retrospective cohort study was conducted from a single, high volume, academic hospital. Health Related Quality of Life outcomes were obtained from Outcomes Based Electronic Research Database and electronic medical record chart review. Subsidence was defined as a loss of 2 mm or more in the anterior or posterior disk height. Spinopelvic alignment parameters measured were sacral slope, pelvic tilt, pelvic incidence, lumbar lordosis, segmental lordosis, and pelvic incidence-lumbar lordosis mismatch. Fusion rates were assessed by the Brantigan-Steffee criteria. RESULTS: The study included a total of 137 patients (108 PEEK, 29 titanium). Overall, no significant changes were noted between the 2 groups at 3 month or 1-year follow-up. Perioperatively, patients did report improvement in all outcome parameters within the PEEK and titanium groups. No significant difference was noted in subsidence rate between the 2 groups. Segmental lordosis significantly increased within the PEEK (+4.8 degrees; P<0.001) and titanium (+4.6 degrees; P=0.003) cage groups, however no difference was noted between groups. No significant difference was noted in fusion between the PEEK and titanium cage cohorts (92.6% vs. 86.2%; P=0.36). CONCLUSION: Overall, while PEEK and titanium cages exhibit unique biomaterial properties, our study shows that there were no significant differences with respect to patient-reported outcomes or radiographic outcomes between the 2 groups at the 1-year follow-up time point. LEVEL OF EVIDENCE: Level III.

Power Analysis for Null Hypothesis Significance Testing.

Before conducting a scientific study, a power analysis is performed to determine the sample size required to test an effect within allowable probabilities of Type I error (α) or Type II error (ß). The power of a study is related to Type II error by 1-ß. Most scientific studies set α=0.05 and power=0.80 as minimums. More conservative study designs will decrease α or increase power, which will require a larger sample size. The third and final parameter required for a power analysis is the effect size (ES). ES is a measure of the strength of the observation in the outcome of interest (ie, the dependent variable). ES must be estimated from pilot studies or published values. A small ES will require a larger sample size than a large ES. It is possible to detect statistically significant findings even for very small ES, if the sample size is sufficiently large. Therefore, it is also essential to evaluate whether ES is sufficiently large to be clinically meaningful.

Patient Outcomes Following Short-segment Lumbar Fusion Are Not Affected by PI-LL Mismatch.

STUDY DESIGN: This is a retrospective cohort study. OBJECTIVE: The objective of this study was to further elucidate the relationship between pelvic incidence-lumbar lordosis (PI-LL) mismatch and surgical outcomes in patients undergoing short segment lumbar fusions for degenerative lumbar disease. SUMMARY OF BACKGROUND DATA: There are few studies examining the relationship between spinopelvic parameters and patient reported outcome measurements (PROMs) in short segment lumbar degenerative disease. MATERIALS AND METHODS: A retrospective review was conducted at single academic institution. Patients undergoing 1- or 2-level lumbar fusion were retrospectively identified and separated into 2 groups based on postoperative PI-LL mismatch ≤10 degrees (NM) or PI-LL mismatch >10 degrees (M). Outcomes including the Physical Component Score (PCS)-12, Mental Component Score (MCS)-12, Oswestry Disability Index (ODI), Visual Analog Scale (VAS) back and leg scores were analyzed. Absolute PROM scores, the recovery ratio and the percentage of patients achieving minimum clinically important difference between groups were compared and a multiple linear regression analysis was performed. RESULTS: A total of 306 patients were included, with 59 patients in the NM group and 247 patients in the M group. Patients in the M group started with a higher degree of PI-LL mismatch compared with the NM group (22.2 vs. 7.6 degrees, P<0.001) and this difference increased postoperatively (24.7 vs. 2.5 degrees, P<0.001). There were no differences between the 2 groups in terms of baseline, postoperative, or Δ outcome scores (P>0.05). In addition, having a PI-LL mismatch was not found to be an independent predictor of any PROM on multivariate analysis (P>0.05). CONCLUSION: The findings in this study show that even though patients in the M group had a higher degree of mismatch preoperatively and postoperatively, there was no difference in PROMs. LEVEL OF EVIDENCE: Level III.

The Management of Acute Lumbar Stress Reactions of the Pedicle and Pars in Professional Athletes Playing Collision Sports.

Acute stress reactions in the lumbar spine most commonly occur in athletes at the pars interarticularis followed by the pedicle. These reactions occur as a result of repetitive microtrauma from supraphysiological loads applied to the lumbar spine. Characteristic motions such as trunk extension and twisting are also thought to play a role and may be sport-specific. Other risk factors include increased lumbar lordosis, hamstring and thoracolumbar fascia tightness, and abdominal weakness. On physical examination, pain is typically reproduced with lumbar hyperextension. Currently, magnetic resonance imaging or nuclear imaging remain the most sensitive imaging modalities for identifying acute lesions. In the elite athlete, management of these conditions can be challenging, particularly in those playing collision sports such as American football, hockey, or rugby. Nonoperative treatment is the treatment of choice with rehabilitation programs focused on pain-free positioning and progressive strengthening. Operative treatment is rare, but may be warranted for patients symptomatic for >12 months. Specialized diagnosis protocols as well as treatment and return to play guidelines from 4 physicians treating elite athletes playing collision sports are presented and reviewed.

Depression Identified on the Mental Component Score of the Short Form-12 Affects Health Related Quality of Life After Lumbar Decompression Surgery.

STUDY DESIGN: This was a retrospective comparative study. OBJECTIVE: The goal of this study was to further elucidate the relationship between preoperative depression and patient-reported outcome measurements (PROMs) following lumbar decompression surgery. SUMMARY OF BACKGROUND DATA: The impact of preoperative depression on PROMs after lumbar decompression surgery is not well established. METHODS: Patients undergoing lumbar decompression between 1 and 3 levels were retrospectively identified. Patients were split into 2 groups using a preoperative Mental Component Score (MCS)-12 threshold score of 45.6 or 35.0 to identify those with and without depressive symptoms. In addition, patients were also split based on a pre-existing diagnosis of depression in the medical chart. Absolute PROM scores, the recovery ratio and the percent of patients achieving minimum clinically important difference between groups were compared, and a multiple linear regression analysis was performed. RESULTS: A total of 184 patients were included, with 125 (67.9%) in the MCS-12 >45.6 group and 59 (32.1%) in the MCS-12 ≤45.6 group. The MCS-12 ≤45.6 and MCS<35.0 group had worse baseline Oswestry Disability Index (ODI) (P<0.001 for both) and Visual Analogue Scale Leg (P=0.018 and 0.024, respectively) scores. The MCS ≤45.6 group had greater disability postoperatively in terms of SF-12 Physical Component Score (PCS-12) (39.1 vs. 43.1, P=0.015) and ODI (26.6 vs. 17.8, P=0.006). Using regression analysis, having a baseline MCS-12 scores ≤45.6 before surgical intervention was a significant predictor of worse improvement in terms of PCS-12 [ß=-4.548 (-7.567 to -1.530), P=0.003] and ODI [ß=8.234 (1.433, 15.035), P=0.010] scores than the MCS-12 >45.6 group. CONCLUSION: Although all patients showed improved in all PROMs after surgery, those with MCS-12 ≤45.6 showed less improvement in PCS-12 and ODI scores.

How Does Smoking Influence Patient-reported Outcomes in Patients After Lumbar Fusion?

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: The goal of this study was to determine the effect of smoking on patient-reported outcome measurements (PROMs) after lumbar fusion surgery. SUMMARY OF BACKGROUND DATA: Although smoking is known to decrease fusion rates after lumbar fusion, there is less evidence regarding the influence of smoking on PROMs after surgery. METHODS: Patients undergoing between 1 and 3 levels of lumbar fusion were divided into 3 groups on the basis of preoperative smoking status: never smokers (NS); current smokers (CS); and former smokers (FS). PROMs collected for analysis include the Physical Component Score (PCS-12), Mental Component Score (MCS-12), Oswestry Disability Index (ODI), and Visual Analogue Scale back (VAS back) and leg (VAS leg) pain scores. Preoperative and postoperative PROMs were compared between groups. A multiple linear regression analysis was performed to determine whether preoperative smoking status was a predictor of change in PROM scores. RESULTS: A total of 220 (60.1%) NS, 52 (14.2%) CS, and 94 (25.7%) FS patients were included. Patients in most groups improved within each of the PROMs analyzed (P<0.05). VAS leg pain (P=0.001) was found to significantly differ between groups, with NS and FS having less disability than CS (3.6 vs. 2.0, P=0.010; and 3.6 vs. 2.4, P=0.022; respectively). Being a CS significantly predicted less improvement in ODI (P=0.035), VAS back (P=0.034), and VAS leg (P<0.001) compared with NS. In addition, NS had a significantly lower 30-day readmission rate than CS or FS (3.2% vs. 5.8% and 10.6%, respectively, P=0.029). CONCLUSION: CS exhibited worse postoperative VAS leg pain and a lower recovery ratio than never smokers. In addition, being in the CS group was a significant predictor of decreased improvement in ODI, VAS back, and VAS leg scores. LEVEL OF EVIDENCE: Level III.

Processing and Handling Cost of Single-use Versus Traditional Instrumentation for 1 Level Lumbar Fusions.

STUDY DESIGN: A single center, observational prospective clinical study. OBJECTIVE: The aim of this study was to compare the instrumentation-related cost and efficiency of single-use instrumentation versus traditional reusable instrument trays. SUMMARY OF BACKGROUND DATA: Single-use instrumentation provides the opportunity to reduce costs associated with cleaning and sterilizing instrumentation after surgery. Although previous studies have shown single-use instrumentation is effective in other orthopedic specialties, it is unclear if single-use instrumentation could provide economic advantages in spine surgery. MATERIALS AND METHODS: A total of 40 (20 reusable instrumentation and 20 single-use instrumentation) lumbar decompression (1-3 level) and fusion (1 level) spine surgeries were collected. Instrument handling, opening, setup, re-stocking, cleaning, sterilization, inspection, packaging, and storage were recorded by direct observation for both reusable and single-use instrumentation. The rate of infection was noted for each group. RESULTS: Mean time of handling instruments by the scrub nurse was 11.6 (±3.9) minutes for reusable instrumentation and 2.1 (±0.5) minutes for single-use instrumentation. Mean cost of handling reusable instruments was estimated to be $8.52 (±$2.96) per case, and the average cost to reprocess a single tray by Sterilization Processing Department (SPD) was $58. Thus, the median cost for sterilizing 2 reusable trays per case was $116, resulting in an average total Costresuable of $124.52 (±$2.96). Mean cost of handling single-use instrumentation was estimated to be $1.57 ($0.38) per case. CONCLUSION: Single-use instrumentation provided greater cost savings and reduced time from the opening of instrumentation to use in surgery when compared with reusable instrumentation.

Are Patient Outcomes Affected by the Presence of a Fellow or Resident in Lumbar Decompression Surgery?

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aim of this study was to determine whether the presence of a fellow or resident (F/R) compared to a physician assistant (PA) affected surgical variables or short-term patient outcomes. SUMMARY OF BACKGROUND DATA: Although orthopedic spine fellows and residents must participate in minimum number of decompression surgeries to gain competency, the impact of trainee presence on patient outcomes has not been assessed. METHODS: One hundred and seventy-one patients that underwent a one- to three-level lumbar spine decompression procedure at a high-volume academic center were retrospectively identified. Operative reports from all cases were examined and patients were placed into one of two groups based on whether the first assist was a F/R or a PA. Univariate analysis was used to compare differences in total surgery duration, 30-day and 90-day readmissions, infection and revision rates, patient-reported outcome measures (Short Form-12 Physical Component Score and Mental Component Score, Oswestry Disability Index, Visual Analog Scale [VAS] Back, VAS Leg) between groups. Multiple linear regression was used to assess change in each patient reported outcome and multiple binary logistic regression was used to determine significant predictors of revision, infection, and 30- or 90-day readmission. RESULTS: Seventy-eight patients were included in the F/R group compared to 93 patients in the PA group. There were no differences between groups for total surgery time, 30-day or 90-day readmissions, infection, or revision rates. Using univariate analysis, there were no differences between the two groups pre- or postoperatively (P > 0.05). Using multivariate analysis, presence of a surgical trainee did not significantly influence any patient reported outcome and did not affect infection, revision, or 30- and 90-day readmission rates. CONCLUSION: This is one of the first studies to show that the presence of an orthopedic spine fellow or resident does not affect patient short-term outcomes in lumbar decompression surgery. LEVEL OF EVIDENCE: 3.

Establishing the Injury Severity of Subaxial Cervical Spine Trauma: Validating the Hierarchical Nature of the AO Spine Subaxial Cervical Spine Injury Classification System.

STUDY DESIGN: Global cross-sectional survey. OBJECTIVE: The aim of this study was to validate the AO Spine Subaxial Cervical Spine Injury Classification by examining the perceived injury severity by surgeon across AO geographical regions and practice experience. SUMMARY OF BACKGROUND DATA: Previous subaxial cervical spine injury classifications have been limited by subpar interobserver reliability and clinical applicability. In an attempt to create a universally validated scheme with prognostic value, AO Spine established a subaxial cervical spine injury classification involving four elements: injury morphology, facet injury involvement, neurologic status, and case-specific modifiers. METHODS: A survey was sent to 272 AO Spine members across all geographic regions and with a variety of practice experience. Respondents graded the severity of each variable of the classification system on a scale from zero (low severity) to 100 (high severity). Primary outcome was to assess differences in perceived injury severity for each injury type over geographic regions and level of practice experience. RESULTS: A total of 189 responses were received. Overall, the classification system exhibited a hierarchical progression in subtype injury severity scores. Only three subtypes showed a significant difference in injury severity score among geographic regions: F3 (floating lateral mass fracture, P = 0.04), N3 (incomplete spinal cord injury, P = 0.03), and M2 (critical disk herniation, P = 0.04). When stratified by surgeon experience, pairwise comparison showed only two morphological subtypes, B1 (bony posterior tension band injury, P = 0.02) and F2 (unstable facet fracture, P = 0.03), and one neurologic subtype (N3, P = 0.02) exhibited a significant difference in injury severity score. CONCLUSION: The AO Spine Subaxial Cervical Spine Injury Classification System has shown to be reliable and suitable for proper patient management. The study shows this classification is substantially generalizable by geographic region and surgeon experience, and provides a consistent method of communication among physicians while covering the majority of subaxial cervical spine traumatic injuries.Level of Evidence: 4.

The Outcomes of Patients With Neck Pain Following ACDF: A Comparison of Patients With Radiculopathy, Myelopathy, or Mixed Symptomatology.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The goal of the present study was to determine whether neck pain responds differently to anterior cervical discectomy and fusion (ACDF) between patients with cervical radiculopathy and/or cervical myelopathy. SUMMARY OF BACKGROUND DATA: Many patients who undergo ACDF because of radiculopathy/myelopathy also complain of neck pain. However, no studies have compared the response of significant neck pain to ACDF. METHODS: Patients undergoing one to three-level primary ACDF for radiculopathy and/or myelopathy with significant (Visual Analogue Scale [VAS] ≥ 3) neck pain and a minimum of 1-year follow-up were included. Based on preoperative symptoms patients were split into groups for analysis: radiculopathy (R group), myelopathy (M group), or both (MR group). Groups were compared for differences in Health Related Quality of Life outcomes: Physical Component Score-12, Mental Component Score (MCS)-12, Neck Disability Index, VAS neck, and VAS arm pain. RESULTS: Two hundred thirty-five patients met inclusion criteria. There were 117 patients in the R group, 53 in the M group, and 65 in the MR group. Preoperative VAS neck pain was found to be significantly higher in the R group versus M group (6.5 vs. 5.5; P = 0.046). Postoperatively, all cohorts experienced significant (P < 0.001) reduction in VAS neck pain, (ΔVAS neck; R group: -2.9, M: -2.5, MR: -2.5) with no significant differences between groups. However, myelopathic patients showed greater improvement in absolute MCS-12 scores (P = 0.011), RR (P = 0.006), and % minimum clinically important difference (P = 0.013) when compared with radiculopathy patients. This greater improvement remained following regression analysis (P = 0.025). CONCLUSION: Patients with substantial preoperative neck pain experienced significant reduction in their neck pain, disability, and physical function following ACDF, whether treated for radiculopathy or myelopathy. However, in this study, only myelopathy patients had significant improvements in their mental function as represented by MCS improvements. LEVEL OF EVIDENCE: 3.

Risk Factors for Prolonged Opioid Use and Effects of Opioid Tolerance on Clinical Outcomes After Anterior Cervical Discectomy and Fusion Surgery.

STUDY DESIGN: Retrospective study. OBJECTIVE: The aim of this study was to determine risk factors for prolonged opioid use and to investigate whether opioid-tolerance affects patient-reported outcomes following anterior cervical discectomy and fusion (ACDF) surgery. SUMMARY OF BACKGROUND DATA: There is a lack of consensus on risk factors that can affect continued opioid use after cervical spine surgery and the influence of opioid use on patient-reported outcomes. METHODS: Ninety-two patients who underwent ACDF for degenerative cervical pathologies were retrospectively identified and their opioid usage before surgery was investigated using a state-sponsored prescription drug monitoring registry. Opioid-naïve and opioid tolerant groups were defined using criteria most consistent with the Federal Drug Administration (FDA) definition. Patient-reported outcomes were then collected, including the Short Form-12 (SF-12) Physical Component (PCS-12) and Mental Component (MCS-12), the Neck Disability Index (NDI), the Visual Analogue Scale Neck (VAS neck) and the Visual Analogue Scale Arm (VAS Arm) pain scores. Logistic regression was used to determine predictors for prolonged opioid use following ACDF. Univariate and multivariate analyses were conducted to compare change in outcomes over time between the two groups. RESULTS: Logistic regression analysis demonstrated that opioid tolerance was a significant predictor for prolonged opioid use after ACDF (odds ratio [OR]: 18.2 [1.46, 226.4], P = 0.02). Duration of usage was also found to be a significant predictor for continued opioid use after surgery (OR: 1.10 [1.0, 1.03], P = 0.03). No other risk factors were found to be significant predictors. Both groups overall experienced improvements in patient-reported outcomes after surgery. Multiple linear regression analysis, controlling for patient demographics, demonstrated that opioid-tolerant user status positively affected change in outcomes over time for NDI (ß = -13.7 [-21.8,-5.55], P = 0.002) and PCS-12 (ß = 6.99 [2.59, 11.4], P = 0.003) but no other outcomes measured. CONCLUSION: Opioid tolerance was found to be a significant predictor for prolonged opioid use after ACDF. Additionally, opioid-naïve and opioid-tolerant users experienced overall improvements across PROMs following ACDF. Opioid-tolerance was associated with NDI and PCS-12 improvements over time compared to opioid-naïve users. LEVEL OF EVIDENCE: 4.

Hepatitis C Virus Infection as a Predictor of Complications and Increased Costs Following Primary Lumbar Fusion Surgery.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aim of this study was to identify whether hepatitis C virus (HCV) diagnosis influences in-hospital lengths of stay (LOS), postoperative complications, readmission rates, or costs following primary posterior lumbar fusions in an elective setting. SUMMARY OF BACKGROUND DATA: Although joint arthroplasty literature has shown increased complication rates and costs for patients seropositive with HCV without liver disease compared to those without HCV, this comorbidity has not been explored in the spine literature. To our knowledge, this is the first publication in the lumbar spine literature to solely focus on HCV as the disease burden. METHODS: A national database was queried for patients who underwent primary lumbar spine fusion for degenerative lumbar pathology with Medicare insurance from 2005 to 2014. The 90-day postoperative complication rates, readmission rates, and treatment costs were queried. To limit confounding, HCV patients were matched with a control cohort of non-HCV patients using patient demographics, treatment modality, and comorbid conditions, and then analyzed by multivariate logistic regression. Patients with active liver disease were excluded to better isolate HCV as the comorbidity. RESULTS: A cohort of 28,841 patients were included in the final analysis. Postoperatively, compared to those without HCV infection, those with HCV had significantly higher odds of blood transfusions (odds ratio [OR]: 3.06), pneumonia (OR: 2.49), respiratory failure (OR: 2.49), urinary tract infections (OR: 1.89), wound-/implant-related infections (OR: 1.74), cerebrovascular events (OR: 1.70), or any postoperative complication within 90 days (OR: 2.93; all P < 0.0001). Furthermore, HCV positive patients had higher day of surgery costs ($28,713.26 vs. $25,448.26, P < 0.0001) and 90-day costs ($33,447.39 vs. $29,016.77, P < 0.0001). There was not a significant difference for patients with HCV infection compared to those without in regard to hospital LOS (10 days vs. 8 days, P = 0.332) and rates of a 90-day readmission (0.37% vs. 0.22%; OR: 1.70, 95% confidence interval: 1.00-2.90, P: 0.050). CONCLUSION: In patients undergoing primary lumbar fusion, a seropositivity for HCV without liver disease is associated with higher costs and complication rates, including higher rates of blood transfusion requirements and pneumonia-related complications. This data shed new light on elective spine surgery in HCV patients and may influence the risks and benefits considerations for surgeons considering lumbar fusion in this population. LEVEL OF EVIDENCE: 3.