Behavior of higher-order MDD on energy ratios at the interface of thermoelastic and piezothermoelastic mediums.

This paper investigates the intricate energy distribution patterns emerging at an orthotropic piezothermoelastic half-space interface by considering the influence of a higher-order three-phase lags heat conduction law, accompanied by memory-dependent derivatives (referred to as HPS) within the underlying thermoelastic half-space (referred to as TS). This study explores the amplitude and energy ratios of reflected and transmitted waves. These waves span various incident types, including longitudinal, thermal, and transversal, as they propagate through the TS and interact at the interface. Upon encountering the interface, an intriguing dynamic unfolds: three waves experience reflection within the TS medium, while four waves undergo transmission into the HPS medium. A graphical representation effectively illustrates the impact of higher-order time differential parameters and memory to offer comprehensive insights. This visual representation reveals the nuanced fluctuations of energy ratios with the incidence angle. The model astutely captures diverse scenarios, showcasing its ability to interpret complex interface dynamics.

Nasal nitric oxide flux from the paranasal sinuses.

PURPOSE OF REVIEW: Upper airway nitric oxide (NO) is physiologically important in airway regulation and defense, and can be modulated by various airway inflammatory conditions, including allergic rhinitis and chronic rhinosinusitis - with and without polyposis. Paranasal sinuses serve as a NO 'reservoir', with concentrations typically exceeding those measured in lower airway (fractional exhaled NO or FeNO) by a few orders of magnitude. However, the dynamics of NO flux between the paranasal sinuses and main nasal airway, which are critical to respiratory NO emission, are poorly understood. RECENT FINDINGS: Historically, NO emissions were thought to be contributed mostly by the maxillary sinuses (the largest sinuses) and active air movement (convection). However, recent anatomically-accurate computational modeling studies based on patients' CT scans showed that the ethmoid sinuses and diffusive transport dominate the process. SUMMARY: These new findings may have a substantial impact on our view of nasal NO emission mechanisms and sinus physiopathology in general.

Tissue-engineered composite tracheal grafts create mechanically stable and biocompatible airway replacements.

We tested composite tracheal grafts (CTG) composed of a partially decellularized tracheal graft (PDTG) combined with a 3-dimensional (3D)-printed airway splint for use in long-segment airway reconstruction. CTG is designed to recapitulate the 3D extracellular matrix of the trachea with stable mechanical properties imparted from the extraluminal airway splint. We performed segmental orthotopic tracheal replacement in a mouse microsurgical model. MicroCT was used to measure graft patency. Tracheal neotissue formation was quantified histologically. Airflow dynamic properties were analyzed using computational fluid dynamics. We found that CTG are easily implanted and did not result in vascular erosion, tracheal injury, or inflammation. Graft epithelialization and endothelialization were comparable with CTG to control. Tracheal collapse was absent with CTG. Composite tracheal scaffolds combine biocompatible synthetic support with PDTG, supporting the regeneration of host epithelium while maintaining graft structure.

Evidence of Nasal Cooling and Sensory Impairments Driving Patient Symptoms With Septal Deviation.

OBJECTIVES/HYPOTHESIS: About 260,000 septoplasties are performed annually in the US to address nasal septal deviation (NSD). Yet, we do not consistently understand what aspects of NSD result in symptoms. STUDY DESIGN: Blinded cohort study. METHODS: Two fellowship-trained surgeons blindly reviewed computerized tomography (CTs) of 10 confirmed NSD patients mixed with 36 healthy controls. All patients were correctly identified, however, 24/36 controls were falsely identified by both surgeons as patients (33.3% specificity), which were grouped as asymptomatic NSD (aNSD), while the remaining controls as non-NSD (healthy). Acoustic rhinometry, rhinomanometry, individual CT-based computational fluid dynamics and nasal sensory testing were applied to address the puzzling questions of why these aNSD had no symptoms and, more fundamentally, what caused symptoms in sNSD patients. RESULTS: aNSD reported no nasal symptoms - Nasal Obstruction Symptom Evaluation score (sNSD: 60.50 ± 13.00; aNSD: 5.20 ± 5.41; non-NSD: 6.66 ± 7.17, P < .05); 22-item Sino-Nasal Outcome Test score (sNSD: 32.60 ± 14.13; aNSD: 10.04 ± 10.10; non-NSD: 9.08 ± 12.42, P < .001). No significant differences in measured nasal resistance, minimum cross-sectional area (MCA), degree of septal deviation, and nasal airflow distributions were found between sNSD and aNSD groups. Only three variables differentiate sNSD versus aNSD: anterior averaged heat flux on deviated side, inferior turbinate peak heat flux on non-deviated side, and nasal cool sensitivity measured by menthol lateralization threshold, with no significant differences among these variables found between the two healthy groups (aNSD vs. non-NSD). These variables by themselves or combined can differentiate sNSD from controls with higher specificity than the physicians (ROC area under the curve = 0.84 with 70% sensitivity and 91.6% specificity). CONCLUSIONS: This study sheds light on the potential mechanisms of NSD symptomatology: distorted nasal cooling due to NSD exacerbated by poorer nasal mucosal sensitivity. It further supports our previous hypothesis that nasal obstruction complaints do not result directly from obstruction, rather from the capacity of our nose to subjectively sense airflow cooling. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:509-517, 2022.

Use of computational fluid dynamics (CFD) to model observed nasal nitric oxide levels in human subjects.

BACKGROUND: Upper airway nitric oxide (NO) is physiologically important in airway regulation and defense, and nasal NO (nNO) levels typically exceed those in exhaled breath (fractional exhaled NO [FeNO]). Elevated concentrations of NO sampled from the nose, in turn, reflect even higher concentrations in the paranasal sinuses, suggesting a "reservoir" role for the latter. However, the dynamics of NO flux within the sinonasal compartment are poorly understood. METHODS: Data from 10 human subjects who had previously undergone both real-time nNO sampling and computed tomography (CT) scanning of the sinuses were analyzed using computational fluid dynamics (CFD) methods. Modeled and observed nNO values during the initial 2-s transient ("spike") during nasal exhalation were then compared. RESULTS: Examining the initial 2-s transient spike for each subject (as well as the pooled group), there was a statistically significant correlation between modeled and observed nNO levels, with r values ranging from 0.43 to 0.89 (p values ranging from <0.05 to <0.0001). Model performance varied between subjects, with weaker correlations evident in those with high background (FeNO) levels. In addition, the CFD simulation suggests that ethmoid sinuses (>60%) and diffusion process (>54%) contributed most to total nasal NO emissions. CONCLUSION: Analysis of this dataset confirms that CFD is a valuable modeling tool for nNO dynamics, and highlights the importance of the ethmoid sinuses, as well as the role of diffusion as an initiating step in sinonasal NO flux. Future model iterations may apply more generally if baseline FeNO is taken into account.

Computational modeling of nasal nitric oxide flux from the paranasal sinuses: Validation against human experiment.

BACKGROUND: Nitric oxide (NO) is important in respiratory physiology and airway defense. Although the paranasal sinuses are the major source of nasal NO, transport dynamics between the sinuses and nasal cavities are poorly understood. METHODS: Exhaled nasal NO tracings were measured in two non-asthmatic subjects (one with allergic rhinitis, one without) using NO analyzer connected via face mask. We subsequently performed computational fluid dynamics NO emission simulations based on individual CT scans and compared to the experimental data. RESULTS: Simulated exhaled NO tracings match well with experimental data (r > 0.84, p < 0.01) for both subjects, with measured peaks reaching 319.6 ppb in one subject (allergic-rhinitis), and 196.9 ppb in the other. The CFD simulation accurately captured the peak differences, even though the initial sinus NO concentration for both cases was set to the same 9000 ppb based on literature value. Further, the CFD simulation suggests that ethmoid sinuses contributed the most (>67%, other sinuses combined <33%) to total nasal NO emission in both cases and that diffusion contributes more than convective transport. By turning off diffusion (setting NO diffusivity to ~0), the NO emission peaks for both cases were reduced by >70%. CONCLUSION: Historically, nasal NO emissions were thought to be contributed mostly by the maxillary sinuses (the largest sinuses) and active air movement (convection). Here, we showed that the ethmoid sinuses and diffusive transport dominate the process. These findings may have a substantial impact on our view of nasal NO emission mechanisms and sinus physiopathology in general.

Regeneration of partially decellularized tracheal scaffolds in a mouse model of orthotopic tracheal replacement.

Decellularized tracheal scaffolds offer a potential solution for the repair of long-segment tracheal defects. However, complete decellularization of trachea is complicated by tracheal collapse. We created a partially decellularized tracheal scaffold (DTS) and characterized regeneration in a mouse model of tracheal transplantation. All cell populations except chondrocytes were eliminated from DTS. DTS maintained graft integrity as well as its predominant extracellular matrix (ECM) proteins. We then assessed the performance of DTS in vivo. Grafts formed a functional epithelium by study endpoint (28 days). While initial chondrocyte viability was low, this was found to improve in vivo. We then used atomic force microscopy to quantify micromechanical properties of DTS, demonstrating that orthotopic implantation and graft regeneration lead to the restoration of native tracheal rigidity. We conclude that DTS preserves the cartilage ECM, supports neo-epithelialization, endothelialization and chondrocyte viability, and can serve as a potential solution for long-segment tracheal defects.

Inferior meatus augmentation procedure (IMAP) normalizes nasal airflow patterns in empty nose syndrome patients via computational fluid dynamics (CFD) modeling.

BACKGROUND: Empty nose syndrome (ENS) is a controversial upper airway disorder most commonly associated with tissue loss from the inferior turbinates. The inferior meatus augmentation procedure (IMAP) has been shown to effectively reduce ENS symptoms in a durable manner, but the precise mechanisms that may govern this symptomatic improvement remain unknown. METHODS: Five patients with ENS who underwent bilateral IMAP via submucosal costal cartilage implant were assessed. Pre-implant and 6 months post-implant computed tomography (CT) imaging for each ENS patient was analyzed in a blinded fashion using computational fluid dynamics (CFD) modeling to investigate intrapatient changes in airflow parameters. RESULTS: Following surgery, ENS patients have significantly improved symptoms as indexed by Empty Nose Syndrome 6-Item Questionnaire (ENS6Q) scoring (pre-implant: 14.00 ± 4.06 [mean ± standard deviation]; 95% confidence interval [CI], 10.44 to 17.56; post-implant: 4.8 ± 2.77; 95% CI, 2.37 to 7.23; Cohen's d = 2.64; p = 0.02). Using CFD, a significant shift in nasal airflow patterns was observed, where airflow deviates away from the middle meatus upon hitting the implant (pre-implant: 67.13% ± 11.14%; 95% CI, 60.22% to 74.04%; post-implant: 46.18% ± 12.81%; 95% CI, 38.23% to 54.12%; d = 1.74; p < 0.05) toward the inferior meatus (pre-implant: 30.55% ± 11.29%; 95% CI, 23.55% to 37.55%; post-implant: 42.59% ± 9.60%; 95% CI, 36.63 to 48.54%; d = 1.14; p < 0.05). No significant changes were found in nasal resistance (pre-implant: 0.102 ± 0.015; 95% CI, 0.092 to 0.112 Pa*s/mL; post-implant: 0.105 ± 0.041; 95% CI, 0.081 to 0.130 Pa*s/mL). In addition, the improvement of ENS6Q scoring significantly correlated with percent reduction in aberrant airflow through the middle meatus (R2 = 0.60, p = 0.04). CONCLUSION: This study supports our prior working hypothesis that disordered vectors of nasal airflow congregate in the middle meatus contribute to ENS symptoms, not nasal resistance. Moreover, these data illuminate a paradoxical, but consistent, restoration of nasal airflow to the inferior meatus following the replacement of turbinate tissue volume in the inferior meatus via IMAP surgery, potentially due to the Coanda effect.

Regional Peak Mucosal Cooling Predicts Radiofrequency Treatment Outcomes of Nasal Valve Obstruction.

OBJECTIVES/HYPOTHESIS: Low energy radiofrequency may offer effective treatment for narrow or obstructed nasal valve, yet its precise mechanism is not fully understood. STUDY DESIGN: Prospective, nonrandomized, case series. METHODS: Twenty prospective patients with internal nasal valve obstruction underwent office-based Vivaer treatment (Aerin Medical, Inc) under local anesthesia. Computational fluid dynamics (CFD) models were constructed based on the pre- and 90 days post-procedure computed tomography (CT) scans to identify salient changes in nasal airflow parameters. RESULTS: Patients' Nasal Obstruction Symptom Evaluation score (NOSE: pre-treatment 78.89 ± 11.57; post-treatment 31.39 ± 18.30, P = 5e-7) and Visual Analog Scale of nasal obstruction (VAS: pre-treatment 6.01 ± 1.83; post-treatment 3.44 ± 2.11, P = 1e-4) improved significantly at 90 days after the minimally invasive approach. Nasal airway volume in the treatment area increased ~7% 90 days post-treatment (pre-treatment 5.97 ± 1.20, post-treatment 6.38 ± 1.50 cm3 , P = .018), yet there were no statistically significant changes in the measured peak nasal inspiratory flowrate (PNIF, pre-treatment: 60.16 ± 34.49; post-treatment: 72.38 ± 43.66 ml/s; P = .13) and CFD computed nasal resistance (pre-treatment: 0.096 ± 0.065; post-treatment: 0.075 ± 0.026 Pa/(ml/s); P = .063). As validation, PNIF correlated significantly with nasal resistance (r = 0.47, P = .004). Among all the variables, only the peak mucosal cooling posterior to the nasal vestibule significantly correlated with the NOSE at baseline (r = -0.531, P = .023) and with post-treatment improvement (r = 0.659, P = .003). CONCLUSION: Minimal remodeling of the nasal valve (7% in this study) may have a profound effect on perceived nasal obstruction, despite little effect on nasal resistance, or PNIF. The results corroborated our previous findings that subjective relief of nasal obstruction correlates with regional mucosal cooling rather than nasal resistance or peak flow rate, a potential target for future effective, personalized therapeutic approaches. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E1760-E1769, 2021.

Current trends in the diagnosis and management of gestational diabetes mellitus in the United States.

OBJECTIVE: To assess current practice patterns among members of the Society for Maternal-Fetal Medicine (SMFM) with respect to the diagnosis and management of gestational diabetes mellitus (GDM). METHODS: A 38 question survey on GDM diagnosis and management was distributed to SMFM members. RESULTS: 2330 SMFM members were surveyed with a 40% response rate. Overall, 90.6% of respondents recommend a 2-step (versus a 1-step) diagnostic test. Cutoff values for the 1-h-50 g glucose challenge test vary from 130-140 mg/dL, but the majority (83%) adopts Carpenter Coustan criteria for the 3-h-100 g oral glucose tolerance test. The majority recommend glucose testing four times a day, with 55% preferring post-prandial testing at 2 h. Glyburide is used by 57% as a first-line agent, while 4% use metformin. Long-acting insulin analogs (glargine and/or detemir) are used by 46% and 33.6% of respondents, respectively. Antenatal testing is recommended by 38.7% for diet-controlled GDM compared to 98.7% for pharmacologically controlled GDM, with 56% starting by 34 weeks gestation. Most respondents recommend delivery of diet-controlled GDM at 40 weeks and pharmacologically controlled GDM at 39 weeks. Most (69%) offer elective cesarean section for an estimated fetal weight of >4500 g. CONCLUSIONS: There is significant variation in the diagnosis and management of GDM among SMFM members.

Comparison of VivaSight double-lumen tube with a conventional double-lumen tube in adult patients undergoing video-assisted thoracoscopic surgery.

The efficiency of a double-lumen tube depends on its position in the airways, which can be verified by fibreoptic bronchoscopy. The VivaSight DL is a single-use double-lumen tube with a camera embedded in the tube's right side. The view from the camera appears continuously on a monitor. In this prospective study of 71 adult patients, we compared intubation times using either the VivaSight DL or a conventional double-lumen tube. Median (IQR [range]) duration of intubation with visual confirmation of tube position was significantly reduced using the VivaSight DL compared with the conventional double-lumen tube (51 (42-60 [35-118]) s vs 264 (233-325 [160-490]) s, respectively, p < 0.0001). None of the patients allocated to the VivaSight DL required fibreoptic bronchoscopy during intubation or surgery. The VivaSight DL enables significantly more rapid intubation compared with the conventional double-lumen tube.

Randomized controlled trial of insulin detemir versus NPH for the treatment of pregnant women with diabetes.

OBJECTIVE: We sought to determine if insulin detemir (IDet) is noninferior to insulin neutral protamine Hagedorn (NPH) for the treatment of gestational diabetes mellitus (GDM) and type 2 diabetes mellitus (T2DM) in pregnancy. STUDY DESIGN: We conducted a randomized, controlled noninferiority trial of women with GDM and T2DM who entered our Diabetes in Pregnancy Program from March 2013 through October 2014. Exclusion criteria were type 1 diabetes, age <18 years, and insulin allergy. Women who failed to achieve good glycemic control (GC) (mean blood glucose [BG] <100 mg/dL) on diet and/or hypoglycemic agents were randomized to receive either IDet or NPH, with short-acting insulin aspart added as needed. Patients were instructed to test BG 4 times a day (fasting and 2-hour postprandial). Targets of GC were fasting BG <90 mg/dL and postprandial BG <120 mg/dL, and insulin was adjusted as needed to achieve the targets. The primary outcome was overall mean BG during insulin treatment; secondary outcomes included overall mean postprandial and fasting BG, median number of weeks to achieve GC, percent of patients with overall GC, maternal weight gain, perinatal/neonatal outcomes, and number of hypoglycemic events. Power analysis (90% power) determined that 88 patients would need to be randomized, assuming a maximal acceptable difference in overall mean BG of 7 mg/dL (SD ± 10 mg/dL). A per protocol analysis was performed. RESULTS: In all, 105 women were randomized. Eighteen women were excluded leaving 87 participants for analysis (45 NPH, 42 IDet). Maternal characteristics were similar in both groups. The difference in the mean BG of the groups was 2.1 mg/dL with a 1-sided upper 95% confidence limit of 5.5 mg/dL (less than the maximal acceptable difference of 7 mg/dL; P = .2937). There was no significant difference in the primary outcome when an intent-to-treat analysis was performed or when the T2DM patients were excluded. The time to achieve GC was similar in both groups. There were no differences in perinatal outcomes and maternal weight gain among the groups. There were more hypoglycemic events per patient in the NPH group. CONCLUSION: IDet is noninferior to insulin NPH for the treatment of GDM and T2DM in pregnancy.

Autovalidation rates in an outpatient coagulation laboratory.

INTRODUCTION: To determine the rates of autovalidation in our outpatient coagulation laboratory. METHODS: We retrospectively identified all coagulation tests analyzed during the month of January 2014 from our laboratory information system (LIS) (N = 16 116), from around 800 000 active members of Clalit Health Services (a health maintenance organization). The integrated system includes a single centrifugation of all collection tubes, analyzers that rerun or reflex tests according to the test results, and a laboratory information system that sends orders to the analyzer, autovalidates test results, and automatically sends critical value results to a list for immediate physician communication. Reasons for technician validation are tests rerun for confirmation or because of analyzer errors and test results that require reflex testing. All other test results are sent automatically to the laboratory information system without the need for technician review. RESULTS: There were 362 test results with analyzer errors, 91 results rerun for confirmation (thrombophilia test results outside the reference interval), and 50 tests with mixing studies and reflex testing for factor XI activity levels (total = 3.1%, 503/16116), resulting in an autovalidation rate of 96.9% (95% confidence interval - 96.6-97.2%). CONCLUSIONS: We conclude that an integrated system can result in a high autovalidation rate in a high-volume outpatient coagulation laboratory.

Evaluation of a new double-lumen endobronchial tube with an integrated camera (VivaSight-DL(™) ): a prospective multicentre observational study.

The VivaSight-DL(™) is a new single-use double-lumen endobronchial tube with an integrated camera. We studied this device in 151 consecutive patients scheduled for elective thoracic surgery in four different hospitals. Endobronchial intubation was successful in 148 patients (98%) (95% CI 94-99%). Median (IQR [range]) endobronchial intubation time was 59 (47-82 [17-932]) s and lung isolation was successfully achieved in 147 (99%) patients (95% CI 96-99%). A fibreoptic bronchoscope was required to assist endobronchial tube placement in 19 (13%) patients (95% CI 8-19%). Sore throat was reported by 37 (25%) patients (95% CI 18-33%), but no major complications were observed. We have reported the successful use of the VivaSight double-lumen tube for endobronchial intubation in a multicentre observational trial.

Early rehabilitation treatment in newborns with congenital muscular torticollis.

BACKGROUND: Congenital Muscular Torticollis (CMT) is the most common form of torticollis in infants; on clinical presentation it is classified into 3 types: 1) postural torticollis, with postural deformity only in the neck; 2) muscular torticollis, where neck deformity is associated with muscle tightness and restricted passive range of motion (ROM); and 3) sternomastoid tumor or pseudotumor, with a fibrotic, sternocleido-mastoid muscle mass and passive ROM limitations. AIM: The aim of this study was to evaluate the physical therapy outcome of infants with CMT treated either by parents using a home exercise program, or by a physical therapist. DESIGN: Longitudinal study. SETTING: Outpatients with CMT at our Department of Physical Medicine and Rehabilitation. POPULATION: Fifty consecutive newborns with CMT, referred by the primary pediatrician: METHODS: In our study, 50 infants with CMT were evaluated and treated either by a physical therapist or by parents using a home program. RESULTS: Sixteen females (32%) and 34 males (68%), aged 10.2 weeks (SD 6.66); 23 of the infants (46%) presented with more severe articular limitations than the others (P=0.002) and were therefore prescribed outpatient treatment by a physical therapist; the remaining 27 less severe cases (54%) were prescribed a home therapy program. 49 infants achieved full resolution after an average of 81.06 days (SD 64.05) of rehabilitation treatment. The group of patients who were treated at home achieved resolution more quickly (72.8 vs. 91.1 days), although statistical significance was not reached. CONCLUSIONS: Infants with CMT who were treated early, either at home or in the outpatient clinic, completely recovered normal neck movement in a short time. It is important not to discharge patients until they have achieved full resolution of CMT symptoms to exclude the minimal risk of relapse. CLINICAL REHABILITATION IMPACT: This study demonstrates the importance of early treatment in cases of congenital muscular torticollis.

Acute leukemia detection rate by automated blood count parameters and peripheral smear review.

INTRODUCTION: It is unclear what minimal criteria will identify all new cases of acute leukemia in adults in various settings. METHODS: To determine the adult acute leukemia detection rate of the various criteria, we recorded complete blood count (CBC) test results from consecutive patients with leukemia (130 hospitalized patients and 96 outpatients) and from consecutive patients without leukemia (34,827 hospitalized and 33,695 outpatients). RESULTS: Basic criteria for a reflex review (hemoglobin, platelets, and a five-part differential) detected 91% of new hospital leukemia patients (118 of 130) compared to 75% (72 of 96) outpatients. No cases were missed if we did reflex testing when there was either one of the basic criteria or an increased proportion of large unstained cells (LUC), but five cases were missed using the blast flag instead of the LUC. Adding the LUC to basic criteria resulted in the detection of all cases of acute leukemia. The cost of detection of one case of acute leukemia was 1029 and 425 peripheral smear reviews in hospital and outpatients, respectively. CONCLUSION: We conclude that basic criteria available on most hematology analyzers along with the LUC identify all adult patients with acute leukemia in both hospital and outpatient settings with minimal peripheral smear review rates.

Labor induction in nulliparous women with an unfavorable cervix: double balloon catheter versus dinoprostone.

OBJECTIVE: We sought to compare the efficacy of the double-balloon catheter and dinoprostone for induction of labor among nulliparous women with an unfavorable cervix. STUDY DESIGN: Nulliparous women with a Bishop score <6 were randomized to receive a 10-mg intra-vaginal dinoprostone insert or a double-balloon catheter. Primary outcome was time to delivery. Statistical analyses were performed by intention to treat using the chi-square, Fisher's exact, and Student's t-test, as appropriate. RESULTS: The mean induction-to-delivery time was shorter in the double-balloon group as compared to the dinoprostone group (17.9±5.8 vs. 26.3±9.7 h) as was the time from induction to vaginal delivery (19.13±5 vs. 24.45±8.7 h, respectively). More women in the catheter group were delivered within 24 h compared to the dinoprostone group (87.1% vs. 47.4%). Approximately 50% of women in both groups delivered by cesarean section. CONCLUSION: Induction of labor with the double-balloon catheter in nulliparous women with an unfavorable cervix is associated with a shorter time to delivery compared to dinoprostone.

Trial of labor versus repeat cesarean: are patients making an informed decision?

OBJECTIVE: Most women eligible for a trial of labor after a cesarean (TOLAC) undergo an elective repeat cesarean section (ERCS). We hypothesized that this is largely because of poor patient education. STUDY DESIGN: This was a prospective study of women who presented to our hospital from November 2010 through July 2011 who were candidates for TOLAC. Women filled out a questionnaire prior to their scheduled ERCS or upon admission for TOLAC. A χ(2) and a Student t test were used, as appropriate. RESULTS: The study included 155 women, 87 for TOLAC and 68 for ERCS. Women in both groups demonstrated a lack of knowledge on the risks and benefits of TOLAC and ERCS. When patients perceived their providers as having a preference for ERCS, very few chose TOLAC, whereas the majority chose TOLAC if this was their provider's preference. CONCLUSION: Candidates for TOLAC appear to know little about the risks and benefits associated with their mode of delivery, and provider preference affects this choice.