SIR Flat CAP (Safety In Radiology - Flat-Packed Compact Airborne Precaution): A Low-Cost, Portable, Negative-Pressure Isolation Barrier Shield for Protecting Frontline Healthcare Workers.

Introduction Multiple barrier shields have been described since the start of the COVID-19 pandemic. Most of these are bulky and designed for use in the main anesthetic or radiology departments. We developed a portable, negative-pressure barrier shield designed specifically for portable ultrasound examinations. A novel supine cough generation model was developed together with a reverse qualitative fit test to simulate real-world aerosol droplet generation and dispersion for evaluating the effectiveness of the barrier shield. We report the technical specifications of this design, named "SIR Flat CAP" from Safety In Radiology - Flat-packed Compact Airborne Precaution, as well as its performance in reducing the spread of droplets and aerosols.  Methods The barrier shield was constructed using 1 mm acrylic panels, clear packing tape, foam double-sided tape, and surgical drapes. Negative pressure was provided via hospital wall suction. A supine cough generation model was developed to simulate cough droplet dispersal. A reverse qualitative fit test was used to assess for airborne transmission of microdroplets. Results The supine cough generation model was able to replicate similar results to previously reported supine human cough generation dispersion. The use of the barrier shield with negative-pressure suction prevented the escape of visible droplets, and no airborne microdroplets were detected by reverse qualitative fit testing from the containment area. Conclusions The barrier shield significantly reduces the escape of visible and airborne droplets from the containment area, providing an additional layer of protection to front-line sonographers.

Utility of Seated Lateral Radiographs in the Diagnosis and Classification of Lumbar Degenerative Spondylolisthesis.

STUDY DESIGN: Retrospective cohort study. PURPOSE: Our goal was to determine which radiographic images are most essential for degenerative spondylolisthesis (DS) classification and instability detection. OVERVIEW OF LITERATURE: The heterogeneity in DS requires multiple imaging views to evaluate vertebral translation, disc space, slip angle, and instability. However, there are several restrictions on frequently used imaging perspectives such as flexion-extension and upright radiography. METHODS: We assessed baseline neutral upright, standing flexion, seated lateral radiographs, and magnetic resonance imaging (MRI) for patients identified with spondylolisthesis from January 2021 to May 2022 by a single spine surgeon. DS was classified by Meyerding and Clinical and Radiographic Degenerative Spondylolisthesis classifications. A difference of >10° or >8% between views, respectively, was used to characterize angular and translational instability. Analysis of variance and paired chi-square tests were utilized to compare modalities. RESULTS: A total of 136 patients were included. Seated lateral and standing flexion radiographs showed the greatest slip percentage (16.0% and 16.7%), while MRI revealed the lowest (12.2%, p <0.001). Standing flexion and lateral radiographs when seated produced more kyphosis (4.66° and 4.97°, respectively) than neutral upright and MRI (7.19° and 7.20°, p <0.001). Seated lateral performed similarly to standing flexion in detecting all measurement parameters and categorizing DS (all p >0.05). Translational instability was shown to be more prevalent when associated with seated lateral or standing flexion than when combined with neutral upright (31.5% vs. 20.2%, p =0.041; and 28.1% vs. 14.6%, p =0.014, respectively). There were no differences between seated lateral or standing flexion in the detection of instability (all p >0.20). CONCLUSIONS: Seated lateral radiographs are appropriate alternatives for standing flexion radiographs. Films taken when standing up straight do not offer any more information for DS detection. Rather than standing flexion-extension radiographs, instability can be detected using an MRI, which is often performed preoperatively, paired with a single seated lateral radiograph.

The Implication of Preoperative Central Stenosis on Patient-Reported Outcomes After Lumbar Decompression Surgery.

OBJECTIVE: To assess the impact of central stenosis severity on patient-reported outcomes after lumbar decompression. METHODS: Patient diagnosis, demographics, and surgical characteristics were collected via query search and manual chart review of electronic medical records. The inclusion criteria were posterior lumbar decompressions from 2014-2020, with accessible magnetic resonance imaging reports. As previously validated by Lee et al., central stenosis was determined on magnetic resonance imaging and graded as none, mild, moderate, or severe. Patients were dichotomized into 2 groups to improve statistical power for comparisons: none or mild central stenosis and moderate or severe central stenosis. Patient-reported outcome measures (PROMs) were compared between cohorts at 1 year postoperatively. Statistical significance was set at P < 0.05. RESULTS: On bivariate analysis, no significant differences were noted between cohorts with regard to preoperative, 1-year postoperative, and delta PROMs. In addition, no significant difference in the number of patients attaining minimal clinically important difference (MCID) for each PROM was noted between cohorts. With the exception of mental score of the Short Form-12 survey, all intragroup preoperative to postoperative PROMs indicated significant improvement (all P < 0.05) after lumbar decompression surgery. Multivariate regression identified moderate or severe central canal stenosis as a significant independent predictor of improvement in visual analog scale back (estimate = -1.464, P = 0.045). CONCLUSIONS: We demonstrate that patients with moderate or severe central spinal stenosis may have more improvement in back pain than those with mild or no central stenosis after lumbar spine decompression surgery.

Clinical Outcomes of Robotic Versus Freehand Pedicle Screw Placement After One-to Three-Level Lumbar Fusion.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: The purpose of this study is to compare patient-reported outcome measures (PROMs) for patients undergoing one-to three-level lumbar fusion using robotically assisted vs freehand pedicle screw placement. METHODS: Patients who underwent either robotically assisted or freehand pedicle screw placement for one-to three-level lumbar fusion surgery from January 1, 2014 to August 31, 2020 at a single academic institution were identified. Propensity score matching was performed based on demographic variables. Clinical and surgical outcomes were compared between groups. Recovery Ratios (RR) and the proportion of patients achieving the minimally clinically important difference (%MCID) were calculated for Oswestry Disability Index, PCS-12, MCS-12, VAS Back, and VAS Leg at 1 year. Surgical outcomes included complication and revision rates. RESULTS: A total of 262 patients were included in the study (85 robotic and 177 freehand). No significant differences were found in ΔPROM scores, RR, or MCID between patients who underwent robotically assisted vs freehand screw placement. The rates of revision (1.70% freehand vs 1.18% robotic, P = 1.000) and complications (.57% freehand vs 1.18% robotic, P = .546) were not found to be statically different between the 2 groups. Controlling for demographic factors, procedure type (robotic vs freehand) did not emerge as a significant predictor of ΔPROM scores on multivariate linear regression analysis. CONCLUSIONS: Robotically assisted pedicle screw placement did not result in significantly improved clinical or surgical outcomes compared to conventional freehand screw placement for patients undergoing one-to three-level lumbar fusion.

Does Facet Distraction Affect Patient Outcomes After ACDF?

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aim of this study is to determine if there is a correlation between the amount of facet distraction and postoperative patient-reported outcomes after ACDF. METHODS: A retrospective cohort analysis of patients undergoing 1 to 3 level ACDF for degenerative pathologies at a single academic center was performed. Each patient received upright, lateral cervical spine x-rays at the immediate postoperative time point from which interfacet distance (facet distraction) was measured. Patient-reported outcome measures including NDI, PCS-12, MCS-12, VAS Neck, and VAS Arm pain scores were obtained preoperatively and at short-term (<3 months) and long-term (>1 year) follow-up. Receiver operating curves were generated to evaluate the possibility of a critical interfacet distraction distance. Univariate and multivariate analysis were performed to compare outcomes between groups based on the degree of facet distraction. RESULTS: A total of 229 patients met the inclusion criteria. Receiver operating curves failed to yield a critical interfacet distraction distance associated with worse post-operative outcomes. Patients were instead grouped based on facet distraction distance below and above the third quartile (0.8mm-2.0 mm, 2.0mm-3.7 mm), with 173 and 56 patients in each respective group. Univariate analysis did not detect any statistically significant differences in outcome measures, recovery ratio, or % MCID achievement at short- and long-term follow-up between groups. Multivariate analysis also failed to demonstrate any significant differences between the facet distraction groups. CONCLUSION: Increased interfacet distance did not correlate with increased neck pain or disability after an ACDF.

Does change in focal lordosis after spinal fusion affect clinical outcomes in degenerative spondylolisthesis?

Study Design: Retrospective cohort study. Objective: The objective of this study is to determine the effect of focal lordosis and global alignment and proportion (GAP) scores on patient reported outcome measures (PROMs) after posterior lumbar fusion for patients with 1- or 2-level lumbar degenerative spondylolisthesis (DS). Summary of Background Data: In patients with DS, improvements in spinopelvic parameters are believed to improve clinical outcomes. However, the effect of changing focal lordosis in patients with 1-or 2-level degenerative lumbar spondylolisthesis is unclear. Materials and Methods: Postoperative spinopelvic parameters and perioperative focal lordosis changes were measured for 162 patients at a single academic center from January 2013 to December 2017. Patients were divided into three groups: >2° (lordotic group), between 2° and -2° (neutral group), and -2°° (kyphotic group). Patients were then reclassified based on GAP scores. Recovery ratios (RR) and the number of patients achieving the minimal clinically important difference (MCID) were calculated for PROMs. Standard descriptive statistics were reported for patient demographics and outcomes data. Multiple linear regression analysis controlled for confounders. Alpha was set at P < 0.05. Results: There was no significant association between change in focal lordosis and surgical complications including adjacent segment disease (P = 0.282), instrumentation failure (P = 0.196), pseudarthrosis (P = 0.623), or revision surgery (P = 0.424). In addition, the only PROM affected by change in focal lordosis was Mental Component Scores (ΔMCS-12) (lordotic = 2.5, neutral = 8.54, and kyphotic = 5.96, P = 0.017) and RR for MCS-12 (lordotic = 0.02, neutral = 0.14, kyphotic 0.10, P = 0.008). Linear regression analysis demonstrated focal lordosis was a predictor of decreased improvement in MCS-12 (ß = -6.45 [-11.03- -1.83], P = 0.007). GAP scores suggested patients who were correctly proportioned had worse MCID compared to moderately disproportioned and severely disproportioned patients (P = 0.024). Conclusions: The change in focal lordosis not a significant predictor of change in PROMs for disability, pain, or physical function. Proportioned patients based on the GAP score had worse MCID for Oswestry Disability Index. Level of Evidence: III.

Perioperative Chanage in Cervical Lordosis and Health-Related Quality-of-Life Outcomes.

BACKGROUND: Surgeons have scrutinized spinal alignment and its impact on improving clinical outcomes following anterior cervical discectomy and fusion (ACDF). The primary analysis of this study examines the relationship between change in perioperative cervical lordosis (CL) and health-related quality-of-life (HRQOL) outcomes after ACDF. Secondary analysis evaluates the effects of fusion construct length on outcomes in patients grouped by preoperative cervical alignment. METHODS: A retrospective cohort study was performed on an institutional database including patients who underwent 1- to 3-level ACDF. C2-C7 CL was measured preoperatively and at final follow-up. For primary analysis, patients were classified based on their perioperative cervical lordotic correction: (1) kyphotic, (2) maintained, and (3) restored. For secondary analysis, patients were categorized based on their preoperative C2-C7 CL: (1) kyphotic, (2) neutral, and (3) lordotic. Demographics and perioperative change in patient-reported outcome measures were compared between groups. RESULTS: A total of 308 patients were included. A significant difference was noted among maintained, restored, and kyphotic groups in terms of delta physical compositeshort form-12 score (ΔPCS-12) (9.0 vs 10.3 vs 1.5; P = 0.04) and delta visual analog scale score (ΔVAS) for arm pain (-0.9 vs -3.8 vs -0.6; P = 0.03). Regression analysis revealed significantly greater improvement of PCS-12 (ß: 8.6; P = 0.03) and VAS arm (ß: -2.0; P = 0.03) scores in restored patients compared with kyphotic patients. The length of fusion construct in patients grouped by preoperative cervical alignment had no significant impact on the clinical outcomes on regression analysis. CONCLUSIONS: Significantly greater PCS-12 and VAS arm improvement were seen in patients whose cervical sagittal alignment was restored to neutral/lordotic compared with those who remained kyphotic. Multivariate analysis demonstrated no association between construct length and perioperative outcomes. CLINICAL RELEVANCE: The results of this study highlight the importance of sagittal alignment and restoration of CL after short-segment ACDF. Irrespective of preoperative sagittal alignment, the length of ACDF fusion construct does not have a significant impact on clinical outcomes.

CO2 surgical laser for treatment of stress urinary incontinence in women: a randomized controlled trial.

BACKGROUND: Stress urinary incontinence is a common condition that can be treated conservatively and/or surgically. Given the risks of surgery, developing effective nonsurgical treatment options would be beneficial. Some studies have suggested that laser therapy may improve or cure stress urinary incontinence. However, there is a lack of sham-controlled randomized controlled trials to judge treatment efficacy. OBJECTIVE: This study aimed to compare the effects of CO2 vaginal laser vs sham therapy for treating stress urinary incontinence. STUDY DESIGN: This was a multicenter, participant-blinded, sham-controlled, parallel group (1:1) superiority randomized controlled trial performed in outpatient clinics in 2 hospitals. We included women aged 18 to 80 years with objective and subjective stress urinary incontinence. Participants had undertaken or declined supervised pelvic floor muscle training. Intervention was performed using a CO2 fractionated vaginal laser. Participants underwent 3 treatments, 4 weeks apart, with increasing energy and density settings. Sham treatment was performed using an identical technique with a deactivated pedal. The primary outcome was the subjective stress urinary incontinence rate (proportion with leak with cough, sneeze, or laughter) at 3 months after completion of treatment. Secondary outcomes included objective stress urinary incontinence, change in the disease-specific patient-reported outcomes, health-related quality of life, and adverse effects. Categorical outcomes were compared using the chi square test and continuous outcomes using analysis of covariance, adjusting for the baseline score. RESULTS: There were 52 participants who received laser and 49 who received sham treatment. One participant in each group withdrew from the study before the endpoint, and 2 participants in the laser group did not participate in the follow-up visits. Participant mean age was 53 (34-79) years. Mean body mass index was 26.1 (18.1-49.6); 90% were vaginally parous. At 3 months, there was no difference between the sham and active treatment arm in subjective stress urinary incontinence (46 [96%] vs 48 [98%]; relative risk, 0.98 [95% confidence interval, 0.91-1.05]; P=.55) or in objective stress urinary incontinence (37 [80%] vs 33 [80%]; relative risk, 0.99 [95% confidence interval, 0.81-1.23]; P=.995). Patient-reported outcomes and health-related quality of life were also comparable between the groups. Vaginal bleeding occurred in 3 participants after laser and 1 participant after sham treatment. Pain during treatment did not differ between laser and sham treatment. CONCLUSION: We were unable to show an improvement in stress urinary incontinence after CO2 vaginal laser therapy compared with sham treatment.

The Effect of L5-S1 Degenerative Disc Disease on Outcomes of L4-L5 Fusion.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aim was to investigate the clinical relevance of preoperative caudal adjacent segment degeneration (ASD) in patients undergoing isolated L4-5 fusion to determine a threshold of degeneration at which a primary L4-S1 fusion would be warranted. SUMMARY OF BACKGROUND DATA: Increased motion and biomechanical forces across the adjacent caudal segment in isolated L4-L5 fusion leads to concerns regarding the increased incidence of revision surgery because of the development of ASD. METHODS: Patients who underwent isolated L4-L5 fusion between 2014 and 2019 were reviewed. Pfirrmann grading and the disc heights of the caudal level relative to the rostral level were used to quantify preoperative adjacent degenerative disc disease. To assess the influence of preoperative caudal degenerative disc disease, preoperative disc height ratios (DHRs) were compared for patients who reported minimal, moderate, and severe Oswestry disability index (ODI) sores on postoperative assessment. For each patient-reported outcome measure (PROM), adjacent DDD was compared for those who did and did not meet MCID. An area under curve analysis was used to identify a threshold of degeneration impacting outcomes from the preoperative DHR. RESULTS: A total of 123 patients were studied with an average follow-up of 2.11 years. All patients demonstrated a significant improvement in all PROMs after surgery. When categorizing patients based on the severity of postoperative ODI scores, there were no preoperative differences in the L5-S1 Pfirrmann grading or DHRs. There was a significant association between greater preoperative anterior DHR and an increased number patients who met MCID for visual analog scale back. There were no radiographic differences in preoperative L5-S1 Pfirrmann grade or DHR for ODI, visual analog scale leg, MCS-12, or PCS-12. area under curve analysis was not able to identify a preoperative DHR threshold that reflected worse MCID for any PROM. CONCLUSION: No preoperative radiographic indicators of caudal ASD were predictive of worse clinical outcomes after isolated L4-5 fusion. LEVEL OF EVIDENCE: Level III.

Comparison of Outcomes Including or Excluding the Level of Listhesis After ACDF in the Setting of Degenerative Spondylolisthesis.

STUDY DESIGN: This was a retrospective cohort study. OBJECTIVE: The goal of this study is to evaluate the outcomes of patients with cervical degenerative spondylolisthesis (DS) undergoing anterior cervical discectomy and fusion (ACDF), specifically comparing surgeries that include versus exclude the DS level. SUMMARY OF BACKGROUND DATA: DS has been extensively studied in the lumbar spine associated with both back and leg pain leading to worse patient quality of life measures. Conversely, there is a relative dearth of literature regarding surgical and clinical outcomes in the setting of cervical DS. MATERIALS AND METHODS: A total of 315 patients undergoing ACDF between 2014 and 2018 with minimum of 1-year postoperative patient-reported outcome measures (PROMs) were retrospectively reviewed. Forty-six patients were found to have DS and were categorized based on whether an ACDF was performed at the same level (SL) or at a different level (DL) than the spondylolisthesis. Patient demographics, surgical parameters, preoperative and postoperative radiographs, and PROMs were compared between groups. RESULTS: Of the 315 patients, a total of 46 met the inclusion criteria including 21 SL and 25 DL patients. There were no significant differences in patient demographics between the groups. The SL cohort had a significantly worse preoperative sagittal vertical axis (SL: 34.4 vs. 26.1, P=0.025) but no difference in postoperative or delta sagittal vertical axis. Both patient cohorts reported significant postoperative improvement in all PROMs, except Short-Form 12 Mental Component Score in the SL group. There were no differences between the groups regarding Visual Analog Scale Neck, Visual Analog Scale Arm, Neck Disability Index, or Short-Form 12 Physical Component Score. Regression analysis demonstrated SL to be a significant negative predictor for improvement in Short-Form 12 Mental Component Score (ß: -11.27, P=0.10). CONCLUSION: Patients treated only at their neurologically symptomatic levels, excluding asymptomatic listhesis in their construct, can expect equivalent radiographic as well as physical function, disability, and pain outcomes 1 year after ACDF compared with patients whose listhetic level was included in their construct. LEVEL OF EVIDENCE: Level III.

Patients With Preoperative Cervical Deformity Experience Similar Clinical Outcomes to Those Without Deformity Following 1-3 Level Anterior Cervical Decompression and Fusion.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aim was to compare the outcomes of patients with incompletely corrected cervical deformity against those without deformity following short-segment anterior cervical decompression and fusion for clinically significant radiculopathy or myelopathy. SUMMARY OF BACKGROUND DATA: Cervical deformity has increasingly been recognized as a driver of disability and has been linked to worse patient-reported outcomes measures (PROMs) after surgery. METHODS: Patients 18 years or above who underwent 1-3 level anterior cervical decompression and fusion to address radiculopathy and/or myelopathy at a single institution between 2014 and 2018 with at least 1 year of PROMs were reviewed. Patients were categorized based on cervical deformity into 2 groups: sagittal vertebral axis (cSVA) ≥40 mm as the deformity group, and cSVA <40 mm as the nondeformity group. Patient demographics, surgical parameters, preoperative and postoperative radiographs, and minimum 1-year PROMs were compared. RESULTS: Of the 230 patients, 191 (83%) were in the nondeformity group and 39 (17%) in the deformity group. Patients with deformity were more likely to be male (69.2% vs. 40.3%, P<0.001) and have a greater body mass index (32.8 vs. 29.7, P=0.028). The deformity group had significantly greater postoperative cSVA (44.2 vs. 25.1 mm, P<0.001) but also had significantly greater ∆cSVA (-4.87 vs. 0.25 mm, P=0.007) than the nondeformity group. Both groups had significant improvements in visual analog scale arm, visual analog scale neck, Short-Form 12 Physical Component Score, and neck disability index (NDI) (P<0.001). However, the deformity group experienced significantly greater ∆NDI and ∆mental component score (MCS)-12 scores (-19.45 vs. -11.11, P=0.027 and 7.68 vs. 1.32, P=0.009). CONCLUSIONS: Patients with preoperative cervical sagittal deformity experienced relatively greater improvements in NDI and MCS-12 scores than those without preoperative deformity. These results suggest that complete correction of sagittal alignment is not required for patients to achieve significant clinical improvement. LEVEL OF EVIDENCE: III.

Effect of a Mandatory Prescription Drug Monitoring Program on Patient-initiated Phone Calls After Spine Surgery.

STUDY DESIGN: This was a retrospective cohort study. OBJECTIVE: The objective of this study was to determine the effect of a statewide, government-mandated prescription drug monitoring program (PDMP) on patient-initiated phone calls after lumbar and cervical spinal surgery. SUMMARY OF BACKGROUND DATA: Prior studies have examined the most common reasons for a postoperative phone calls, most of which pertain to pain or prescription medications. However, no studies have investigated the effects of mandatory opioid prescription reporting on these calls. METHODS: Patients who underwent lumbar decompression, lumbar fusion, or posterior cervical fusion were retrospectively identified. Patients were sorted into 1 of 2 cohorts based on their procedure date's relation to the initiation of the state's PDMP: "pre-PDMP" and "post-PDMP." All clinical and demographic data were obtained from electronic health records. Telephone communications from or on behalf of patients were retrospectively reviewed. Multivariable logistic regression was performed to determine independent factors associated with a postoperative phone call. RESULTS: Five hundred and twenty-five patients (2689 phone calls) were included in the study. Average number of phone calls per patient increased significantly after PDMP implementation among lumbar (3.27 vs. 5.18, P<0.001), cervical (5.08 vs. 11.67, P<0.001), and all (3.59 vs. 6.30, P<0.001) procedures. Age [odds ratio (OR): 1.05 (1.01, 1.09), P=0.02], cervical procedure [OR: 4.65 (1.93, 11.21), P=0.001], and a post-PDMP date of surgery [OR: 6.35 (3.55, 11.35), P<0.001] were independently associated with an increased likelihood of a postoperative phone call. A higher percentage of calls were in reference to postoperative care (4.6% vs. 2.4%, P=0.01) and wound care (4.3% vs. 1.4%, P<0.001) in the post-PDMP cohort compared with the pre-PDMP cohort. CONCLUSIONS: Patient-initiated telephone calls increased significantly after implementation of a mandatory statewide PDMP. Increasing age, operation involving the cervical spine, and surgery occurring after implementation of the state's PDMP were independently associated with an increased likelihood of postoperative phone call to health care providers.

Circumferential fusion with open versus percutaneous posterior fusion for lumbar isthmic spondylolisthesis.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To investigate the clinical and radiographic differences between patients who underwent anterior lumber interbody fusion (ALIF) with either open or percutaneous posterior fusion for lumbar isthmic spondylolisthesis. SUMMARY OF BACKGROUND DATA: Circumferential fusion for isthmic spondylolisthesis is commonly performed with superior clinical outcomes, fusion rates, and restoration of sagittal balance when compared to posterior fusion alone. The outcomes comparing traditional open versus percutaneous posterior fusion in this setting have not been fully evaluated. METHODS: A retrospective review of patients who underwent ALIF with either traditional open or percutaneous posterior fusion for isthmic spondylolisthesis between 2014 and 2019 was conducted. Patient demographics, surgical characteristics, and radiographic and clinical outcomes were compared between groups. RESULTS: A total of 79 patients were included in the final analysis, with 49 in the Open group and 30 in the Percutaneous group. No differences were found with regard to demographic factors between groups including sex, body mass index (BMI), diabetic status, and smoking status. The percutaneous group had less estimated blood loss (EBL, 69.2 mL) and shorter length of stay (3.06 days) compared to the open group (446 mL, p = 0.017; 3.98 days, p = 0.003). Both groups demonstrated significant improvement in all clinical outcome measures after surgery (PCS-12, MCS-12, ODI, VAS Back, and VAS Leg scores). The percutaneous group achieved greater ∆VAS Back (Open = 3.55, Perc = 5.17; p = 0.045) and also had a significantly greater improvements in recovery ratio for VAS Back (Open: 0.43, Perc: 0.73; p = 0.037) and ODI (Open: 0.40, Perc = 0.67; p = 0.031). Regression analysis demonstrated percutaneous surgery to be significant predictor of superior improvement in VAS Back scores (ß = 1.957, p = 0.027). CONCLUSION: ALIF with percutaneous posterior fusion affords greater improvement in back pain and disability when compared to ALIF with open posterior fusion for isthmic spondylolisthesis. LEVEL OF EVIDENCE: III.

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.

Timing of Preoperative Surgical Antibiotic Prophylaxis After Primary One-Level to Three-Level Lumbar Fusion.

OBJECTIVE: The purpose of this study was to examine the relationship between timing of preoperative surgical antibiotic prophylaxis and postoperative surgical site infections (SSIs) among patients with 1-level to 3-level lumbar fusion. METHODS: Patients having undergone a primary 1-level to 3-level lumbar fusion at a single institution were allocated into 5 groups based on the time from preoperative antibiotic administration to incision (group A, 0-15 minutes; group B, 16-30 minutes; group C, 31-45 minutes; group D, 46-60 minutes; and group E, 61+ minutes). Timing of antibiotic administration as a continuous variable was also analyzed. All patients received irrigation with 3 L of normal saline containing bacitracin as well as local administration of vancomycin powder. SSIs were identified by the definition set forth by the 2017 Centers for Disease Control and Prevention guidelines. RESULTS: Among 1131 patients, 27 (2.4%) were found to have an SSI. Compared with patients with antibiotic administration within 0-15 minutes before incision, patients with administration 61+ minutes before incision (group 4) had significantly higher odds of developing an SSI (P < 0.001). Patients had a 1.05-fold higher likelihood of infection for each additional minute delay of administration before incision (P < 0.001). Receiver operating characteristic analysis reported an area under the curve of 0.733 and 0.776 for time as a continuous and categorical variable, respectively. Age (P = 0.02), body mass index (P = 0.03), diabetes mellitus diagnosis (P = 0.04), and type of antibiotic (P = 0.004) were significant predictors of SSI. CONCLUSIONS: Our results show that preoperative antibiotic administration beyond 1 hour in patients who have undergone lumbar fusion is associated with higher rates of SSI.

Static Versus Expandable Polyether Ether Ketone (PEEK) Interbody Cages: A Comparison of One-Year Clinical and Radiographic Outcomes for One-Level Transforaminal Lumbar Interbody Fusion.

OBJECTIVE: To examine the effect of static versus expandable polyether ether ketone (PEEK) cages on both clinical and radiographic outcomes. METHODS: A retrospective cohort study was conducted on patients who underwent one-level transforaminal lumbar interbody fusion with either a static or expandable PEEK cage. Patient outcomes were obtained from chart review and radiographic outcomes were measured using standing, lateral radiographs. Recovery ratios and the proportion of patients achieving the minimally clinically important difference were calculated for Oswestry Disability Index (ODI), Physical Component Score-12, Mental Component Score-12, visual analogue scale for back, and visual analogue scale for leg at 1 year and compared between groups. Multivariate linear regression analysis was performed to determine the effect of cage type on the change in patient-reported outcome measures, controlling for demographic factors. RESULTS: A total of 240 patients (137 static, 103 expandable) were included in the final analysis. ΔPhysical Component Score-12 scores at 3 months were significantly greater for the static group (16.0 vs. 10.0, P = 0.043) compared with the expandable group. Multivariate regression demonstrated that use of an expandable cage was associated with greater improvements in ΔODI (ß: -7.82, P = 0.048) at 1 year. No differences were found in the perioperative change in sagittal spinal alignment within or between groups at 1 year. Subsidence rates failed to show any statistically significant difference between the 2 groups. CONCLUSIONS: Transforaminal lumbar interbody fusion with an expandable PEEK cage is an independent predictor of improved ODI scores at 1 year. Our study showed no significant differences in subsidence rates or changes in sagittal spinal alignment between static and expandable PEEK cages.

Nonperturbative Infrared Finiteness in a Superrenormalizable Scalar Quantum Field Theory.

We present a study of the IR behavior of a three-dimensional superrenormalizable quantum field theory consisting of a scalar field in the adjoint of SU(N) with a φ^{4} interaction. A bare mass is required for the theory to be massless at the quantum level. In perturbation theory, the critical mass is ambiguous due to IR divergences, and we indeed find that at two loops in lattice perturbation theory the critical mass diverges logarithmically. It was conjectured long ago in [R. Jackiw et al., Phys. Rev. D 23, 2291 (1981)PRVDAQ0556-282110.1103/PhysRevD.23.2291, T. Appelquist et al., Phys. Rev. D 23, 2305 (1981)PRVDAQ0556-282110.1103/PhysRevD.23.2305] that superrenormalizable theories are nonperturbatively IR finite, with the coupling constant playing the role of an IR regulator. Using a combination of Markov Chain Monte Carlo simulations of the lattice-regularized theory, frequentist and Bayesian data analysis, and considerations of a corresponding effective theory, we gather evidence that this is indeed the case.

Comparison Between Three- and Four-Level Anterior Cervical Discectomy and Fusion: Patient-Reported and Radiographic Outcomes.

OBJECTIVE: We compared the long-term clinical and radiographic outcomes after 3- and 4-level anterior cervical discectomy and fusion (ACDF) in a retrospective cohort study. METHODS: Patients who had undergone primary 3- or 4-level ACDF were retrospectively identified. The demographic data and patient-reported outcome measures (PROMs) were collected through a review of the medical records. PROM surveys were administered preoperatively for baseline measurements and at 1 year postoperatively. The surveys included the Neck Disability Index, 12-item short-form physical component summary, 12-item short-form mental component summary, and visual analog scale (VAS) scores for neck and arm pain. The cervical sagittal alignment parameters included C2-C7 lordosis, segmental lordosis, the sagittal vertical axis (SVA), and the T1 slope. Multivariate regression models were used to compare the changes in the PROMs and radiographic measurements over time between 3- and 4-level ACDF. Correlation coefficients were calculated to compare the delta scores for the PROMs and radiographic measurements. RESULTS: The VAS scores for neck and arm pain had significantly improved from baseline in both cohorts. Only the 3-level group showed significant improvements perioperatively in the Neck Disability Index and 12-item short-form physical component summary. No significant differences were found in the improvement in clinical outcomes between the 2 groups. The pooled results demonstrated a significant negative correlation between the perioperative changes in segmental lordosis and VAS scores for arm pain. A significant negative correlation was also found between the perioperative changes in the SVA and 12-item short-form mental component summary and VAS scores for neck pain. C2-C7 lordosis significantly increased postoperatively only in the 3-level ACDF group. CONCLUSIONS: Patients undergoing both 3- and 4-level ACDF experienced significant clinical improvement without significant differences between the 2 groups. The radiographic measures of segmental lordosis and SVA also correlated with the changes in clinical outcomes.

Impact of preoperative weakness and duration of symptoms on health-related quality-of-life outcomes following anterior cervical discectomy and fusion.

BACKGROUND CONTEXT: The majority of patients with preoperative upper extremity weakness show improvements in motor function after anterior cervical discectomy and fusion (ACDF). Although numerous studies have examined both the extent and time course to which motor function can be expected to improve, few have shown that these improvements in motor function translate to improved health related quality of life (HRQOL) outcomes. PURPOSE: The purpose of this study was to examine the effect of preoperative weakness and duration of symptoms on HRQOL outcomes in patients who underwent ACDF. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: Adult patients who underwent an ACDF procedure at an academic hospital from January 2015 to December 2016 by a fellowship-trained spine surgeon. OUTCOME MEASURES: The primary outcomes of interest were HRQOL outcomes: Short Form-12 Physical/Mental Component Scores (SF-12 PCS/MCS), Neck Disability Index (NDI), and Visual Analog Scale Arm/Neck scores (VAS Arm/Neck). METHODS: Patient demographics, surgical case characteristics, and motor strength exams were collected in patients who underwent ACDF over a 2-year period. Preoperative weakness was defined by a strength grade ≤3 (on a scale from 0 to 5) in at least one upper extremity muscle group. Multivariate linear regression analysis was performed to determine the effect of the preoperative weakness on HRQOL outcomes. RESULTS: Of the 276 patients identified, 45 (16.3%) showed evidence of preoperative weakness, 44 (97.8%) of which showed subsequent postoperative motor improvements after ACDF. All patients reported significant improvements in all HRQOL outcome measures. Patients with preoperative weakness reported significantly worse preoperative VAS Arm (6.9 vs. 5.2; p=.01) and VAS Neck (6.1 vs. 4.8; p=.02) pain scores. Compared with patients without preoperative weakness, those with preoperative weakness reported significantly more improvement in NDI (ß: -10.9; p=.001). Patients with symptoms greater than or equal to 12 months and preoperative weakness showed significantly less improvement in NDI (ß: 14.8; p=.03). CONCLUSIONS: Patients with preoperative weakness generally exhibited worse pain and HRQOL measures preoperatively, and showed greater potential for improvement after ACDF. Patients with a shorter duration of preoperative weakness had greater potential for improvement in HRQOL measures after ACDF compared with those with longer duration of symptoms. ACDF is an effective procedure to improve strength and HRQOL measures across all patient groups under appropriate indications.