Robotic resection of extrahepatic cholangiocarcinoma: Institutional outcomes of bile duct cancer surgery using a minimally invasive technique.

BACKGROUND AND OBJECTIVES: The purpose of this study is to report our early experience and outcomes, the first in North America, of Extrahepatic Cholangiocarcinoma (EHC) resection with Roux-en Y Hepaticojejunostomy reconstruction via the robotic approach. METHODS: With Institutional Review Board approval, 15 patients who underwent robotic resection of EHC were studied. RESULTS: Patients were 74 (73 ± 8.9) years of age. There were 9 men and 6 women. Average body mass index was 24 (27 ± 6.3) kg·m-2 . Mean & Median ASA class was 3. Median Tumor size was 2 (2 ± 1.3) cm. There were no intraoperative complications. Operative duration was 453 (443 ± 85.0) minutes and the estimated blood loss was 150 (182 ± 138.4) ml. No patient required admission to the intensive care unit. Hospital length of stay was 4 (6 ± 3.2) days. There was one patient with Clavien-Dindo Class 3 or greater complication. No mortality was seen in this series. DISCUSSION: Robotic resection of EHC is safe, feasible, and reproducible with excellent clinical outcomes. Consequently, the robotic technique should be considered in some patients requiring EHC resection.

Micro-mechanisms of failure in nano-structured maraging steels characterised throughin situmechanical tests.

High-pressure-torsion (HPT) processing introduces a large density of dislocations that form sub-grain boundaries within the refined nano-scale structure, leading to changes in precipitate morphology compared to hot-rolled maraging steels. The impact of such nanostructuring on the deformation and fracture micro-mechanisms is being reported for the first time usingin situcharacterization techniques along with transmission electron microscopy and atom probe tomography analysis, in this study. Digital image correlation has been used to quantify the full field strain maps in regions of severe strain localization as well as to determine the fracture toughness through critical crack tip opening displacements. It is seen that the phenomenon of planar slip leads to strain softening under uniaxial deformation and to crack branching under a triaxial stress state in hot rolled maraging steels. On the other hand, nano-structuring after HPT processing creates a large number of high angle grain boundaries as dislocation barriers, leading to strain hardening under uniaxial tension and nearly straight crack path with catastrophic fracture under triaxial stress state. Upon overaging, the hot-rolled sample shows signature of transformation induced plasticity under uniaxial tension, which is absent in the HPT processed overaged samples, owing to the finer reverted austenite grains containing higher Ni concentration in the latter. In the overaged fracture test samples of both the hot-rolled and HPT conditions, crack tips show a signature of strain induced transformation of the reverted austenite to martensite, due to the accompanying severe strain gradients. This leads to a higher fracture toughness even while achieving high strengths in the overaged conditions of the nanocrystalline HPT overaged samples. The results presented here will aid in design of suitable heat treatment or microstructure engineering of interface dominated nano-scale maraging steels with improved damage tolerance.

Management of lymphocele following anterior lumbar interbody fusion, case report and review of literature.

While anterior lumbar interbody fusion (ALIF) is known as an established and safe procedure for treatment of degenerative disc disease, albeit rare, the development of postoperative intra-abdominal or retroperitoneal collection of lymph warrants timely diagnosis and management. This study presents the case of a 62-year-old male who underwent L4-L5 and L5-S1 ALIF and developed a persistent left-sided fluid collection, resulting in a symptomatic retroperitoneal lymphocele confirmed by computed tomography (CT). After percutaneous drainage by interventional radiology (IR), output remained high at 1 liter (L) per day, necessitating sclerotherapy with doxycycline and ethanol. In the absence of improvement, a lymphangiogram demonstrating a persistent lymph leak and glue embolization was performed. Due to refractory symptoms, retroperitoneal exploration with methylene blue dye was utilized for lymphatic mapping, and a lymphatic capillary leak in proximity to the left iliac artery was identified and successfully ligated with resolution of symptoms. With suspected fluid collections following ALIF, confirmation with CT or ultrasound (US) imaging followed by percutaneous drainage and testing of fluid is necessary. In mild cases, drainage alone or nonsurgical chemical sclerotherapy may suffice. In symptomatic refractory cases, localization of the site with lymphangiogram or US-guided injection of methylene blue dye allows for easier identification and definitive management with either transabdominal laparoscopic fenestration or retroperitoneal surgical exploration and ligation.

Exposure to bile acids alters the intracellular location and function of MnSOD in Barrett's esophagus.

BACKGROUND: Oxidative stress secondary to bile-acid exposure has been associated with metaplastic degeneration of normal esophageal mucosa into Barrett's esophagus (BE) cells and eventually esophageal adenocarcinoma. We previously reported that the macromolecular response of BE cells to this stress was largely regulated by the expression of manganese-dependent mitochondrial superoxide dismutase (MnSOD). As the mitochondrion plays a vital role in MnSOD activation, this study sought to determine the location and activity of MnSOD within BE cells after exposure to oxidative stress. METHODS: A human BE cell line, BAR-T cell, was exposed 0.4 mM concentrations of taurocholic acid (Tau) or a 0.4 mM 1:1 mixture of bile salts for 4 h. Cell viability was performed with 3-(4, 5-dimthyl-thiazol-2-yl)-2, 5-diphenyltetrazolium bromide assays. Proteins were extracted and separated into mitochondrial, nuclear, and cytoplasmic fractions followed by analysis by a western blot and enzymatic activities. RESULTS: BAR-T cell showed resistance to the bile-salt insults. Expression of MnSOD was significantly increased in the cells exposed to a mixture of bile acids and Tau versus control. Mitochondria MnSOD is abundant and highly active. Nuclear fraction displayed presence of both MnSOD and Cu/zinc superoxide dismutase secondary to bile-acid exposure; however, the MnSOD was inactive in nuclear fraction. CONCLUSIONS: This is the first study to specifically evaluate cellular fraction MnSOD expression, increased in BE cells in response to the oxidative stress of bile exposure. Mitochondrial MnSOD contributes to resistance of BAR-T cells to the bile-salt insults. Further investigation is required to determine the potential correlation between bile exposure and BE to adenocarcinoma progression via MnSOD-mediated cell signaling.

The Effect of American Society of Anesthesiologists Score and Operative Time on Surgical Site Infection Rates in Major Abdominal Surgeries.

BACKGROUND: The objective of this study was to evaluate the influence of two crucial variables, the American Society of Anesthesiologists (ASA) score and operative time, on the occurrence of surgical site infections (SSIs) in the context of major abdominal surgical procedures. METHODOLOGY: A cross-sectional research study involved patients undergoing various gastrointestinal surgical procedures. Surgical details, procedure duration, and ASA score were meticulously documented. Patients were observed for surgical site infections (SSIs) during their inpatient stay until discharge. Following their discharge, patients were monitored in the outpatient department for a minimum of 30 days post-surgery, and those who underwent mesh procedures were observed for one year. RESULTS: In the overall study population, surgical site infections were identified in 42 cases, constituting 6.7%. There was a significant association between ASA grade and the incidence of surgical site infections (p=0.001), indicating a higher prevalence of infections in cases with elevated ASA grades. Furthermore, a statistically significant association exists between the average duration of surgery and the occurrence of surgical site infections (p=0.001). The mean surgery duration for cases with infections is reported as 206.33 min, with a standard deviation of 103.73, while for cases without infections, the mean duration is 99.72 min, with a standard deviation of 79.71. In the multivariate analysis, it was found that an ASA score of 3 or higher and operative time exceeding 90 min were identified as independent factors for predicting the likelihood of surgical site infections. CONCLUSION:  The significant associations identified between the American Society of Anesthesiologists (ASA) grade, average surgery duration, and SSIs underscore the importance of comprehensive preoperative assessment and procedural management in infection prevention.

Nondestructive material characterization and component identification in sheet metal processing with electromagnetic methods.

Electromagnetic methods for non-destructive evaluation (NDE) are presented, with which sheet metal components can be identified and their material properties can be characterized. The latter is possible with 3MA, the Micromagnetic Multiparametric Microstructure and stress Analyser. This is a combination of several micromagnetic NDE methods that make it possible to analyse the microstructure in a ferromagnetic material and to determine quantitative values of the mechanical material properties or the stress state. In the case of cold forming, the 3MA application for pre-process testing of sheet metal is discussed. Based on the 3MA information, the formability of the sheets can be predicted. To apply 3MA in-line, the influence of the relative speed and the relative distance between the 3MA probe head and the sheet was investigated. In a second study, a spatially resolved eddy current (EC) method was used to create an image of the intrinsic material microstructure of a component for its identification and traceability. It turned out, that these intrinsic fingerprint images can still be recognized even after subsequent plastic deformation or coating of the surface. This enabled the development of a marker-free traceability method for sheet metal processing. It is based on a low-cost array sensor and a specimen identification using robust and partly redundant features of the fingerprint images processed by machine learning (ML).

Impact of American Society of Anesthesiologists' Classification on Postoperative Satisfaction and Clinical Outcomes Following Lumbar Decompression: Cohort-Matched Analysis.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: The aim was to compare patient-reported outcomes (PROMs), minimum clinically important difference (MCID) achievement, and postoperative satisfaction following minimally invasive lumbar decompression in patients stratified by American Society of Anesthesiologists (ASA) classification. SUMMARY OF BACKGROUND DATA: Some guidelines recommend against performing elective procedures for patients with an ASA score of 3 or greater; however, long-term postoperative outcomes are not well described. METHODS: Primary, single-level, minimally invasive lumbar decompression procedures were identified. PROMs were administered at preoperative, 6-week, 12-week, 6-month, 1-year, 2-year timepoints and included Patient-Reported Outcomes Measurement Information System-Physical Function, visual analog scale (VAS) back/leg, Oswestry disability index (ODI), and 12-item short form physical component score. Satisfaction scores were collected postoperatively for VAS back/leg, ODI, and individual ODI subcategories. Patients were grouped (ASA<3, ASA≥3), and propensity scores were matched to control for significant differences. Demographic and perioperative characteristics were compared using χ 2 and the Student's t test. Mean PROMs and postoperative satisfaction were compared at each time point by a 2-sample t test. Postoperative PROM improvement from the preoperative baseline within each cohort was calculated with a paired t test. MCID achievement was determined by comparing ΔPROMs to established thresholds and comparing between groups using simple logistic regression. RESULTS: One hundred and twenty-nine propensity-matched patients were included: 99 ASA<3 and 30 ASA≥3. No significant demographic differences were observed between groups. ASA≥3 patients experienced significantly increased length of stay and postoperative narcotic consumption on surgery day ( P <0.048, all). Mean PROMs and MCID achievement did not differ. The ASA<3 cohort significantly improved from the preoperative baseline for all PROMs at all postoperative time points. ASA<3 patients demonstrated higher levels of postoperative satisfaction at 6 weeks for VAS leg, VAS back, ODI, sleeping, lifting, walking, standing, sex, travel, and at 6 months for VAS back ( P <0.045, all). CONCLUSION: ASA≥3 patients may achieve similar long-term clinical outcomes to ASA<3 patients, though they may show poorer short-term satisfaction for disability, leg pain, and back pain, which could be related to differing preoperative expectations.

Anterior Cervical Discectomy and Fusion Versus Cervical Disc Replacement for a Workers' Compensation Population in an Ambulatory Surgical Center.

STUDY DESIGN: Retrospective Cohort. OBJECTIVE: To evaluate patient-reported outcome measures (PROM) and minimal clinically important difference (MCID) achievement outcomes between anterior cervical discectomy and fusion (ACDF) and cervical disk replacement (CDR) in the Workers' Compensation (WC) population. SUMMARY OF BACKGROUND DATA: No studies to our knowledge have compared PROMs and MCID attainment between ACDF and CDR among patients with WC insurance undergoing surgery in an outpatient ambulatory surgical center (ASC). METHODS: WC insurance patients undergoing primary, single/double-level ACDF/CDR in an ASC were identified. Patients were divided into ACDF versus CDR. PROMs were collected at preoperative/6-week/12-week/6-month/1-year timepoints, including PROMIS-PF, SF-12 PCS/MCS, VAS neck/arm, and NDI. RESULTS: Seventy-nine patients were included, 51 ACDF/28 CDR. While operative time (56.4 vs. 54.4 min), estimated blood loss (29.2 vs. 25.9 mL), POD0 pain (4.9 vs. 3.8), and POD0 narcotic consumption (21.2 vs. 14.5 oral morphine equivalents) were higher in ACDF patients, none reached statistical significance ( P >0.050, all). One-year arthrodesis rate was 100.0% among ACDF recipients with available imaging (n=36). ACDF cohort improved from preoperative for PROMIS-PF from 12 weeks to 1 year, SF-12 PCS at 6 months, all timepoints for VAS neck/arm, and 12 weeks/6 months for NDI ( P ≤0.044, all). CDR cohort improved from preoperative for PROMIS-PF at 6 months, VAS neck/arm from 12 weeks to 1 year, and NDI at 12 weeks/6 months ( P ≤0.049, all). CDR cohort reported significantly lower VAS neck at 12 weeks/1 year and VAS arm at 12 weeks ( P ≤0.039, all). MCID achievement rates did not differ. CONCLUSION: While operative duration/estimated blood loss/acute postoperative pain/narcotic consumption were, on average, higher among ACDF recipients, these were not statistically significant, possibly due to the limited sample size. ACDF and CDR ASC patients generally demonstrated comparable arm pain/disability/physical function/mental health, though neck pain was significantly lower at multiple timepoints among CDR patients. Clinically meaningful PROM improvements were comparable. Larger, multicentered studies are required to confirm our results.

Trends in Emergency Department Computed Tomography Usage for Diagnosis of Peritonsillar Abscess.

OBJECTIVES: Peritonsillar abscess (PTA) is the most common deep neck space infection and a frequent cause for otolaryngology consultation. Patients often undergo computed tomography (CT) scan for confirmation in addition to physical examination. Our aims were to determine whether patients unnecessarily undergo CT scans in the emergency department (ED) when presenting with sore throat and identify physical examination characteristics that predict PTA. METHODS: The electronic medical records of all patients (>18 years) presenting to an ED between June 2014 and June 2015 with a primary diagnosis of acute pharyngitis, acute tonsillitis, or PTA were reviewed for presenting symptoms and diagnostic imaging use. RESULTS: Four hundred eight patients met inclusion criteria; 21 were diagnosed with PTA, including 13 based on history and physical alone. A total of 21 CT scans were ordered, 11 (52.3%) of which did not demonstrate abscess. Soft palatal fullness, uvular deviation, drooling, and muffled voice were all significantly associated with increased CT usage (all P values <.02). Rising subjective pain scores were associated with increased use of CT imaging (P = .029). Multivariable analyses revealed that soft palatal fullness, uvular deviation, and drooling were all significant predictors of PTA (all P values <.001). CONCLUSIONS: Patients with severe symptoms of PTA, including uvular deviation, drooling, and soft palatal fullness, were most likely to undergo CT imaging. Given the high likelihood of PTA, patients presenting with these symptoms could forego CT imaging, reducing exposure to ionizing radiation.

The Influence of Presenting Physical Function on Postoperative Patient Satisfaction and Clinical Outcomes Following Minimally Invasive Lumbar Decompression.

STUDY DESIGN: The study of retrospective cohort. OBJECTIVE: The aim was to compare patient-reported outcome measures (PROMs), satisfaction, and minimum clinically important difference (MCID) achievement following minimally invasive lumbar decompression (MIS-LD) in patients stratified by the preoperative patient-reported outcomes measurement information system physical function (PROMIS-PF) score. SUMMARY OF BACKGROUND DATA: Although prior studies have assessed the predictive utility of preoperative PROMIS-PF scores on patient outcomes in spinal fusion, its utility has not been studied for patients undergoing MIS-LD. METHODS: Primary, single/multilevel MIS-LD procedures were identified. PROMs were administered at preoperative/6-week/12-week/6-month/1-year/2-year time points and included PROMIS-PF/visual analog scale (VAS) back and leg/Oswestry Disability Index (ODI). Satisfaction scores were collected postoperatively. The patients were grouped by preoperative PROMIS-PF score (≤35, >35), with higher scores indicating improved physical function. Demographic/perioperative characteristics were compared using χ 2 /Student t test. Mean PROMs/postoperative satisfaction was compared utilizing 2-sample t test. Postoperative PROM improvement from preoperative was calculated with paired t tests. MCID achievement rates were compared using simple logistic regression. RESULTS: Two hundred and sixteen patients were included, 58 PROMIS-PF≤35 and 158 PROMIS-PF>35. Ethnicity/insurance differed ( P ≤0.004, all). Hospital length of stay was greater for PROMIS-PF>35 ( P =0.042). All preoperative mean PROMs significantly differed except for VAS Back. Several postoperative mean PROMs differed: PROMIS-PF at 6 weeks/12 weeks/6 months/1 year, SF-12 PCS at 6 weeks/12 weeks/1 year, VAS Back at 6 weeks/12 weeks, VAS leg at 6 weeks/12 weeks, and ODI at 6 weeks/12 weeks ( P <0.050, all). All PROMs significantly improved from preoperative at all postoperative time points ( P <0.003, all). The MCID achievement rates differed only for VAS back for 6 weeks, favoring PROMIS-PF>35 cohort ( P =0.001). Postoperative satisfaction was greater in PROMIS-PF>35 cohort for VAS leg at 6 weeks/12 weeks/6 months/2 years, VAS back at 6-weeks/12-weeks, and ODI at all time points ( P <0.037, all). Postoperative satisfaction was greater in PROMIS-PF>35 cohort for individual ODI categories: sleep at 6-weeks/12-weeks/1-year/2-years, lifting, walking, standing, and travel at all time points, and sexual at 6-weeks/12-weeks/1-year/2-years ( P <0.030, all). CONCLUSION: Poorer preoperative PROMIS-PF scores were associated with worse postoperative clinical outcomes and satisfaction. By stratifying patients with preoperative PROMIS-PF scores, surgeons may better predict postoperative clinical improvement and seek to manage patient expectations.

Does Baseline Mental Health Influence Outcomes among Workers' Compensation Claimants Undergoing Minimally Invasive Transforaminal Lumbar Interbody Fusion?

STUDY DESIGN: This was a retrospective cohort study. PURPOSE: This study investigated the influence of preoperative mental health on patient-reported outcome measures (PROMs) and minimal clinically important difference (MCID) among workers' compensation (WC) recipients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). OVERVIEW OF LITERATURE: No studies have evaluated the impact of preoperative mental functioning on outcomes following MIS TLIF among WC claimants. METHODS: WC recipients undergoing single-level MIS TLIF were identified. PROMs of Visual Analog Scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), 12-item Short Form Physical and Mental Composite Scale (SF-12 PCS/MCS), and Patient-Reported Outcomes Measurement Information System Physical Function evaluated subjects preoperatively/postoperatively. Subjects were grouped according to preoperative SF-12 MCS: <41 vs. ≥41. Demographic/perioperative variables, PROMs, and MCID were compared using inferential statistics. Multiple regression was used to account for differences in spinal pathology. RESULTS: The SF-12 MCS <41 and SF-12 MCS ≥41 groups included 48 and 45 patients, respectively. Significant differences in ΔPROMs were observed at SF-12 MCS at all timepoints, except at 6 months (p≤0.041, all). The SF-12 MCS <41 group had worse preoperative to 6-months SF-12 MCS, 12-weeks/6-months VAS back, 12-week VAS leg, and preoperative to 6-months ODI (p≤0.029, all). The SF-12 MCS <41 group had greater MCID achievement for overall ODI and 6-weeks/1-year/overall SF-12 MCS (p≤0.043, all); the SF-12 MCS ≥41 group had greater attainment for 6-month VAS back (p=0.004). CONCLUSIONS: Poorer mental functioning adversely affected the baseline and intermediate postoperative quality-of-life outcomes pertaining to mental health, back pain, and disability among WC recipients undergoing lumbar fusion. However, outcomes did not differ 1-2 years after surgery. While MCID achievement for pain and physical function was largely unaffected by preoperative mental health score, WC recipients with poorer baseline mental health demonstrated higher rates of overall clinically meaningful improvements for disability and mental health.

Single-Level Anterior Lumbar Interbody Fusion versus Minimally Invasive Transforaminal Lumbar Interbody Fusion at L5/S1 for an Obese Population.

STUDY DESIGN: Retrospective study. PURPOSE: To compare perioperative outcomes, patient-reported outcome measures (PROMs), and minimal clinically important difference (MCID) achievement rates for an obese patient cohort between single-level minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF) vs. anterior lumbar interbody fusion (ALIF). OVERVIEW OF LITERATURE: To the best of our knowledge, no study has compared the outcomes of MIS TLIF and ALIF in an obese population. METHODS: Obese patients (body mass index [BMI] ≥30.0 kg/m2) who underwent single-level MIS TLIF or ALIF at L5/S1 were included in the study. Demographic/perioperative variables, presenting patient pathology, and 1-year arthrodesis statistics were collected. PROM scores for Visual Analog Scale (VAS) back/leg, Oswestry Disability Index, 12-item Short Form Physical Composite Scale, and Patient-Reported Outcome Measurement Information System Physical Function (PROMIS-PF) were collected from preoperative and postoperative (6 weeks, 12 weeks, 6 months, 1 year, 2 years) PROMIS-PF. The obese patients were classified based on the procedure they underwent (MIS TLIF vs. ALIF). RESULTS: The criteria were met by 210 patients in total. After coarsened exact matching for Charlson comorbidity index score, degenerative spondylolisthesis, isthmic spondylolisthesis, degenerative scoliosis, foraminal stenosis, insurance, male, and ethnicity, 94 obese patients were included in the total cohort, with 59 receiving MIS TLIF and 35 receiving ALIF. ALIF recipients had higher PROMIS-PF scores at 6 weeks (p=0.014) and 12 weeks (p=0.030), as well as a higher VAS leg at 2 years (p=0.017). Following multiple regression accounting for differences in baseline BMI, only the 6-week PROMIS-PF significantly differed (p=0.028), with no other intergroup differences in mean PROMs between fusion types. Aside from a significantly higher 6-week MCID achievement rate for PROMIS-PF among ALIF recipients (p=0.006), no differences in attainment were observed. CONCLUSIONS: There were no statistically significant differences in perioperative characteristics, fusion rates, PROMs, or MCID achievement between obese patients receiving MIS TLIF vs. ALIF. As a result, our findings indicate that MIS TLIF and ALIF at L5/S1 are equally effective in an obese patient population.

Does Baseline Severity of Arm Pain Influence Outcomes Following Single-Level Anterior Cervical Discectomy and Fusion?

STUDY DESIGN: Retrospective cohort. PURPOSE: To assess preoperative arm pain severity influence on postoperative patient-reported outcomes measures (PROMs) and minimal clinically important difference (MCID) achievement following single-level anterior cervical discectomy and fusion (ACDF). OVERVIEW OF LITERATURE: There is evidence that preoperative symptom severity can affect postoperative outcomes. Few have evaluated this association between preoperative arm pain severity and postoperative PROMs and MCID achievement following ACDF. METHODS: Individuals undergoing single-level ACDF were identified. Patients were grouped by preoperative Visual Analog Scale (VAS) arm ≤8 vs. >8. PROMs collected preoperatively and postoperatively included VAS-arm/VAS-neck/Neck Disability Index (NDI)/12-item Short Form (SF-12) Physical Composite Score (PCS)/SF-12 mental composite score (MCS)/Patient-Reported Outcomes Measurement Information System physical function (PROMIS-PF). Demographics, PROMs, and MCID rates were compared between cohorts. RESULTS: A total of 128 patients were included. The VAS arm ≤8 cohort significantly improved for all PROMs excepting VAS arm at 1-year/2-years, SF-12 MCS at 12-weeks/1-year/2-years, and SF-12 PCS/PROMIS-PF at 6-weeks, only (p ≤0.021, all). The VAS arm >8 cohort significantly improved for VAS neck at all timepoints, VAS arm from 6-weeks to 1-year, NDI from 6-weeks to 6-months, and SF-12 MCS/PROMIS-PF at 6-months (p ≤0.038, all). Postoperatively, the VAS arm >8 cohort had higher VAS-neck (6 weeks/6 months), VAS-arm (12 weeks/6 months), NDI (6 weeks/6 months), lower SF-12 MCS (6 weeks/6 months), SF-12 PCS (6 months), and PROMISPF (12 weeks/6 months) (p ≤0.038, all). MCID achievement rates were higher among the VAS arm >8 cohort for the VAS-arm at 6-weeks/12-weeks/1-year/overall and NDI at 2 years (p ≤0.038, all). CONCLUSIONS: Significance in PROM score differences between VAS arm ≤8 vs. >8 generally dissipated at the 1-year and 2-year timepoint, although higher preoperative arm pain patients suffered from worse pain, disability, and mental/physical function scores. Furthermore, clinically meaningful rates of improvement were similar throughout the vast majority of timepoints for all PROMs studied.

Impact of Postoperative Length of Stay on Patient-Reported and Clinical Outcomes After Anterior Lumbar Interbody Fusion.

BACKGROUND: Existing literature has not yet evaluated the impact of postoperative length of stay (LOS) on patient-reported outcome measures (PROMs) and minimum clinically important difference (MCID) in patients undergoing anterior lumbar interbody fusion (ALIF). The authors investigates the influence of postoperative LOS following ALIF on PROMs and MCID achievement rates. METHODS: A single-surgeon database was retrospectively reviewed for patients undergoing single-level ALIF. The following 2 cohorts were studied: patients with LOS <45 hours and patients with LOS ≥45 hours. The following PROMs were recorded at preoperative and 6-week, 12-week, 6-month, 1-year, and 2-year postoperative timepoints: visual analog scale (VAS) back and leg, Oswestry Disability Index (ODI), 12-item short form (SF-12) physical composite score (PCS), and patient-reported outcome measurement information system physical function. MCID achievement was compared by LOS grouping using χ 2 analysis. The rates of complications by LOS grouping and the relative risk among demographic and perioperative characteristics for a longer hospital stay of ≥45 hours were calculated. RESULTS: A total of 52 subjects were included in each cohort. LOS ≥45 hours demonstrated worse ODI at 6 weeks and SF-12 PCS preoperative and at 12 weeks (P ≤ 0.026, all). LOS <45 hours demonstrated greater MCID rates for all PROMs except VAS back (P ≤ 0.004, all). Postoperative urinary retention (POUR), fever, and total complications (P ≤ 0.003, all) were associated with increased LOS. Diabetes (P = 0.037), preoperative VAS neck ≥7 (P = 0.012), and American Society of Anesthesiologists classification ≥2 (P = 0.003) served as preoperative risk factors for postoperative stay ≥45 hours. CONCLUSION: Following single-level ALIF, patients with shorter LOS demonstrated significantly greater overall MCID achievement for most PROMs. POUR, fever, and total complications were associated with longer LOS and greater blood loss. Diabetes and higher preoperative leg pain were identified as risk factors for longer LOS. CLINICAL RELEVANCE: Patients undergoing ALIF with shorter LOS had greater MCID achievement for disability, physical function, and leg pain outcomes. Patients with greater preoperative leg pain and diabetes may be at risk for longer LOS.

Validation of Neck Disability Index Severity among Patients Receiving One or Two-Level Anterior Cervical Surgery.

STUDY DESIGN: Retrospective cohort. PURPOSE: To evaluate the validity of established severity thresholds for Neck Disability Index (NDI) among patients undergoing anterior cervical discectomy and fusion (ACDF) or cervical disc arthroplasty (CDA). OVERVIEW OF LITERATURE: Few studies have examined the validity of established NDI threshold values among patients undergoing ACDF or CDA. METHODS: A surgical database was reviewed to identify patients undergoing cervical spine procedures. Demographics, operative characteristics, comorbidities, NDI, Visual Analog Scale (VAS), and 12-item Short Form (SF-12) physical and mental composite scores (PCS and MCS) were recorded. NDI severity was categorized using previously established threshold values. Improvement from preoperative scores at each postoperative timepoint and convergent validity of NDI was evaluated. Discriminant validity of NDI was evaluated against VAS neck and arm and SF-12 PCS and MCS. RESULTS: All 290 patients included in the study demonstrated significant improvements from baseline values for all patient-reported outcome measures (PROMs) at all postoperative timepoints (p<0.001) except SF-12 MCS at 2 years (p =0.393). NDI showed a moderate- to-strong correlation (r≥0.419) at most timepoints for VAS neck, VAS arm, SF-12 PCS, and SF-12 MCS (p<0.001, all). NDI severity categories demonstrated significant differences in mean VAS neck, VAS arm, SF-12 PCS, and SF-12 MCS at all timepoints (p<0.001, all). Differences between NDI severity groups were not uniform for all PROMs. VAS neck values demonstrated significant intergroup differences at most timepoints, whereas SF-12 MCS showed significantly different values between most severity groups. CONCLUSIONS: Neck disability is strongly correlated with neck and arm pain, physical function, and mental health and demonstrates worse outcomes with increasing severity. Previously established severity categories may be more applicable to pain than physical function or mental health and may be more uniformly applied preoperatively for cervical spine patients.

Improved detection of genetic markers of antimicrobial resistance by hybridization probe-based melting curve analysis using primers to mask proximal mutations: examples include the influenza H275Y substitution.

OBJECTIVES: Numerous real-time PCR assays have been described for detection of the influenza A H275Y alteration. However, the performance of these methods can be undermined by sequence variation in the regions flanking the codon of interest. This is a problem encountered more broadly in microbial diagnostics. METHODS: In this study, we developed a modification of hybridization probe-based melting curve analysis, whereby primers are used to mask proximal mutations in the sequence targets of hybridization probes, so as to limit the potential for sequence variation to interfere with typing. The approach was applied to the H275Y alteration of the influenza A (H1N1) 2009 strain, as well as a Neisseria gonorrhoeae mutation associated with antimicrobial resistance. Assay performances were assessed using influenza A and N. gonorrhoeae strains characterized by DNA sequencing. RESULTS: The modified hybridization probe-based approach proved successful in limiting the effects of proximal mutations, with the results of melting curve analyses being 100% consistent with the results of DNA sequencing for all influenza A and N. gonorrhoeae strains tested. Notably, these included influenza A and N. gonorrhoeae strains exhibiting additional mutations in hybridization probe targets. Of particular interest was that the H275Y assay correctly typed influenza A strains harbouring a T822C nucleotide substitution, previously shown to interfere with H275Y typing methods. CONCLUSIONS: Overall our modified hybridization probe-based approach provides a simple means of circumventing problems caused by sequence variation, and offers improved detection of the influenza A H275Y alteration and potentially other resistance mechanisms.

Consequences of Progressive Full-Thickness Focal Chondral Defects Involving the Medial and Lateral Femoral Condyles After Meniscectomy: A Biomechanical Study Using a Goat Model.

Background: Full-thickness chondral defects alter tibiofemoral joint homeostasis and, if left untreated, have the potential to progress to osteoarthritis. Purpose: To assess the effects of isolated and dual full-thickness chondral defect size and location on the biomechanical properties of the lateral femoral condyle (LFC) and medial femoral condyle (MFC) during dynamic knee flexion in goat knees without menisci. Methods: In 12 goat knees, we created progressively increasing full-thickness circular chondral defects (3-, 5-, and 7.5-mm diameter) in the weightbearing contact area of flexion and extension in the MFC, the LFC, or both. Each knee was fixed into a custom steel frame and attached to a motor with sensors inserted intra-articularly. For each testing condition, the knee was loaded to 100 N and underwent a dynamic range of motion between 90° of flexion and 30° of extension. The following parameters were collected: contact area, contact pressure, contact force, peak area, and peak pressure. Study Design: Controlled laboratory study. Results: The peak pressure at the defect rim of the MFC at full extension increased by 51.51% from no defect (1.887 MPa) to a 7.5-mm defect (2.859 MPa) (P < .001), and the peak pressure at the defect rim of the LFC at full extension increased by 139.14% from no defect (1.704 MPa) to a 7.5-mm defect (4.075 MPa) (P < .001). The peak pressures for LFC defects at all 3 diameters were significantly greater when compared with dual defects consisting of increasing LFC defect diameter and constant MFC defect diameter (P < .001 for all). Conclusion: Extremely large increases in peak pressure were seen at the rim of articular cartilage defects when evaluated under dynamic loading conditions. Isolated LFC defects experienced a greater increase in defect rim stress concentrations when compared with isolated MFC defects for equivalent increases in defect size. Defect size played a significant role independent of location for peak pressures on the MFC and LFC. Clinical Relevance: Significant rim-loading effects increase with defect size under dynamic loading and may result in increasingly rapid progression of articular cartilage lesions. Within the context of this goat model, findings suggest that lateral compartment chondral lesions are more likely to progress than medial compartment lesions of equivalent size.

History and Evolution of the Minimally Invasive Transforaminal Lumbar Interbody Fusion.

The minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is a popular surgical technique for lumbar arthrodesis, widely considered to hold great efficacy while conferring an impressive safety profile through the minimization of soft tissue damage. This elegant approach to lumbar stabilization is the byproduct of several innovations throughout the past century. In 1934, Mixter and Barr's paper in the New England Journal of Medicine elucidated the role of disc herniation in spinal instability and radiculopathy, prompting surgeons to explore new approaches and instruments to access the disc space. In 1944, Briggs and Milligan published their novel technique, the posterior lumbar interbody fusion (PLIF), involving continuous removal of vertebral bone chips and replacement of the disc with a round bone peg. The following decades witnessed several PLIF modifications, including the addition of long pedicle screws. In 1982, Harms and Rolinger sought to redefine the posterior corridor by approaching the disc space through the intervertebral foramen, establishing the transforaminal lumbar interbody fusion (TLIF). In the 1990s, lumbar spine surgery experienced a paradigm shift, with surgeons placing increased emphasis on tissuesparing minimally invasive techniques. Spurred by this revolution, Foley and Lefkowitz published the novel MIS-TLIF technique in 2002. The MIS-TLIF has demonstrated comparable surgical outcomes to the TLIF, with an improved safety profile. Here, we present a view into the history of the posterior-approach treatment of the discogenic radiculopathy, culminating in the MIS-TLIF. Additionally, we evaluate the hallmark characteristics, technical variability, and reported outcomes of the modern MIS-TLIF and take a brief look at technologies that may define the future MIS-TLIF.

Single-level Minimally Invasive Transforaminal Lumbar Interbody Fusion Versus Anterior Lumbar Interbody Fusion for the Surgical Treatment of Isthmic Spondylolisthesis.

INTRODUCTION: Limited studies have compared minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) with anterior lumbar interbody fusion (ALIF) for the treatment of isthmic spondylolisthesis. This study aims to compare perioperative variables, patient-reported outcome measures (PROMs), and minimal clinically important difference (MCID) achievement rates between these surgical approaches. METHODS: Patients with isthmic spondylolisthesis undergoing primary, single-level MIS TLIF or ALIF were identified in a surgical database. Patients were divided into MIS TLIF and ALIF cohorts. Demographics and perioperative characteristics were collected and compared between groups using the chi square test or Student t-test. PROMs including the Patient-Reported Outcomes Measurement Information System Physical Function, 12-Item Short Form Physical Composite Score, visual analog scale (VAS) back, VAS leg, and Oswestry Disability Index were collected at preoperative, 6-, 12-week, 6-month, 1-, and 2-year time points. Mean PROMs were compared using the Student t-test for independent samples. MCID attainment was determined using established values in the literature; achievement rates by grouping were compared using chi square analysis. RESULTS: One hundred seventy-one patients were included, 121 MIS TLIF and 50 ALIF. No demographic differences were observed. Mean surgical times were 139.7 minutes (MIS TLIF) and 165.5 minutes (ALIF) (P < 0.001). No other perioperative differences were observed. Mean estimated blood loss values were 63.8 mL (MIS TLIF) and 73.7 mL (ALIF). Mean postoperative lengths of stay were 43.9 hours (MIS TLIF) and 42.5 hours (ALIF). Mean PROMs did not markedly differ among groups at any time point. MCID attainment was markedly higher among MIS TLIF patients for the Oswestry Disability Index at 6 weeks (P = 0.046) and 12 weeks (P = 0.007), Patient-Reported Outcomes Measurement Information System Physical Function at 12 weeks (P = 0.015), and VAS leg at 6 weeks (P = 0.031) and 12 weeks (P = 0.045). No other notable differences were observed among MCID achievement by grouping. DISCUSSION: While single-level ALIF demonstrated markedly higher surgical times, other perioperative characteristics and PROMs were comparable among ALIF and MIS TLIF patients. Although MCID achievement rates were generally lower for disability and leg pain among ALIF patients, significance was not reached at 6 months, 1 year, or during the overall postoperative period after fusion.