Team-Based Surgical Approach to Head and Neck Microvascular Free Flap Reconstruction.

Importance: Because microvascular free flap reconstruction is increasingly used to restore function in patients with head and neck cancer, there is a growing need for evidence-based perioperative care. Objective: To assess the association of different team-based surgical approaches with intraoperative and postoperative outcomes for patients undergoing head and neck free flap reconstruction. Design, Setting, and Participants: This retrospective cohort study of 733 patients was conducted at an academic tertiary care medical center. Head and neck oncologic procedures involving microvascular free flap reconstruction with available intraoperative data collected from January 1, 2000, to December 31, 2021, were included. Main Outcomes and Measures: Patient characteristics including demographic characteristics and comorbid conditions, operative variables, length of stay, and postoperative outcomes were measured. Descriptive statistics and effect size measures were performed to compare the 3 intraoperative surgical team approaches, specifically single surgeon, separate 2-team approach, and integrated 2-team approach; 1:1 nearest neighbor matching without caliper was performed to compare single- vs 2-team and separate and integrated 2-team approaches. Effect size measures including Cramer V for dichotomous variables, the Kendall W coefficient of concordance for ordinal variables, and η2 for continuous variables were reported with 95% CIs to describe precision. Results: Among 733 cases, there were no clinically significant differences in patient demographic characteristics, clinicopathologic characteristics, and choice of free flap reconstruction based on intraoperative surgical team approach. The mean (SD) age was 58.7 (12.4) years, and 514 were male (70.1%). In terms of operative and postoperative variables, there was a difference in operative times and intraoperative fluid requirements among the 3 different techniques, with the integrated 2-team approach demonstrating a mean reduction in operative time of approximately 2 hours (η2 = 0.871; 95% CI, 0.852-0.887; mean [SD] operative time = 541 [191] minutes for the single-surgeon approach, 399 [175] minutes for the integrated 2-team approach, and 537 [200] minutes for the separate 2-team approach) and lower fluid requirements of greater than 1 L (η2 = 0.790; 95% CI, 0.762-0.817). In both unadjusted analyses and propensity score matching, there were no clinically significant differences in terms of ischemia time, use of pressors, postoperative complications (including free flap failure, number of return trips to the operating room, length of stay, or 30-day readmission) based on intraoperative team approach. Conclusions and Relevance: Findings suggest that the integrated 2-team surgical approach for complex head and neck microvascular reconstruction can be used to safely decrease operative time, with no difference in postoperative outcomes.

Hypoglossal Nerve Stimulator Explantation: A Case Series.

Hypoglossal nerve stimulation (HGNS) has emerged as a successful surgical treatment strategy for moderate to severe obstructive sleep apnea in patients failing first-line positive airway pressure therapy. HGNS explantation due to adverse events such as pain and infection is rare and has yet to be well described. Here, our correspondence describes the first case series of patients who have undergone explantation of the Inspire HGNS system. Five patients were identified who underwent HGNS explantation. Three patients underwent explantation due to magnetic resonance imaging (MRI) incompatibility. One patient underwent explantation due to poor cosmesis. One patient underwent explantation due to surgical site infection. Average operative explant time was 163 minutes. MRI incompatibility, poor cosmesis, and device-related infection are reasons for HGNS explantation. Future need for MRI or chest wall surgery should be considered in patients being evaluated for HGNS implants.

Evaluation of In-Office Volitional Snore as a Screening Tool for Candidacy for Hypoglossal Nerve Stimulation.

Candidacy evaluation for hypoglossal nerve stimulation (HGNS) is resource intensive. This proof-of-concept study investigates use of in-office volitional snore during flexible laryngoscopy as an efficient, cost-effective screening tool for HGNS evaluation. Adults with moderate to severe obstructive sleep apnea that failed continuous positive airway pressure treatment (n = 41) underwent evaluation for HGNS from 2018 to 2019. Volitional snore and drug-induced sleep endoscopy (DISE) data were collected and scored by VOTE classification (velum/palate, oropharynx, tongue base, epiglottis). A chi-square test of independence was performed that demonstrated a significant relationship between volitional snore and DISE (χ2 = 4.39, P = .036) for velum collapse pattern. Sensitivity and specificity of volitional snore for detecting velum collapse pattern were 93.6% (95% CI, 75.6%-99.2%) and 40% (95% CI, 12.2%-73.8%), respectively, illustrating its utility in screening for HGNS. Patients who demonstrate anterior-posterior velum collapse on volitional snore may be excellent candidates for confirmatory DISE at the time of HGNS implantation.

Computational Study of the Effect of Homogeneous and Heterogeneous Bubbly Flows on Bulk Gas-Liquid Heat Transfer.

A numerical investigation is performed on buoyancy-driven homogeneous and heterogeneous bubbly flows to compare the bulk gas-liquid heat transfer effectiveness for Prandtl (Pr) numbers 0.2-20 and void fractions 〈 α g 〉 0.3-0.5. For this purpose, transient two-fluid model simulations of bubbles rising in a stagnant pool of liquid are conducted in a rectangular box by applying periodic boundary conditions to all the sides. The temperature difference ( Δ T ) between gas and liquid phase is averaged over the rectangular box and monitored with respect to time, the heat transfer rate is studied based on the time at which the Δ T tends to zero. The results of numerical study show that at low Pr numbers, faster decay of Δ T is observed for homogeneous flow of bubbles indicating higher heat transfer rate in comparison with the heterogeneous flow of bubbles for the same void fraction. On the contrary, for high Pr numbers, higher heat transfer rate is observed in heterogeneous flow compared to the homogeneous. The comparison of heat transfer behavior between different void fractions for heterogeneous flow show that, for low Pr numbers higher heat transfer rate is achieved for void fraction 0.4 in comparison with void fraction 0.5. And for high Pr numbers, higher heat transfer is observed for void fraction 0.5 in comparison with void fraction 0.4.

Effectiveness of pediatric drug-induced sleep endoscopy for REM-predominant obstructive sleep apnea.

STUDY OBJECTIVES: Because dexmedetomidine (DEX)-induced sedation mimics non-rapid eye movement (NREM) sleep, its utility in sedating children with REM-predominant disease is unclear. We sought to determine the effectiveness of pediatric drug-induced sleep endoscopy (DISE) using DEX and ketamine for children with REM-predominant OSA, specifically whether or not at least one site of obstruction could be identified. METHODS: A retrospective case series of children without tonsillar hypertrophy undergoing DISE at a tertiary pediatric hospital from 10/2013 through 9/2015 who underwent subsequent surgery to address OSA with polysomnography (PSG) before and after. RESULTS: We included 56 children, mean age 5.6±5.4 years, age range 0.1-17.4 years, mean BMI 20.3±7.4 kg/m2 (76±29 percentile). At least one site of obstruction was identified in all patients, regardless of REM- or NREM-predominance. The mean obstructive apnea-hypopnea index (oAHI) improved (12.6 ± 10.7 to 9.0 ± 14.0 events/h) in children with REM-predominant (P = 0.013) and NREM-predominant disease (21.3 ± 18.9 to 10.3 ± 16.2 events/h) (P = 0.008). The proportion of children with a postoperative oAHI < 5 was 53% and 55% for REM- and NREMpredominant OSA, respectively. Unlike children with NREM-predominant disease, children with REM-predominant disease had significant improvement in the mean saturation nadir (P < 0.001), total sleep time (P = 0.006), and sleep efficiency (P = 0.015). CONCLUSIONS: For children with OSA without tonsillar hypertrophy, DISE using DEX/ketamine was useful to predict at least one site of obstruction, even for those with REM-predominant OSA. DISE-directed outcomes resulted in significant improvements in mean oAHI, total sleep time, sleep efficiency, saturation nadir, and the proportion with oAHI < 5, after surgery for some children with REM-predominant disease.

Growth and Management of Repaired Complete Tracheal Rings after Slide Tracheoplasty.

OBJECTIVE: This study documents the growth and course of repaired complete tracheal rings over time after slide tracheoplasty. STUDY DESIGN: Case series with review. SETTING: Tertiary pediatric academic medical center. SUBJECTS/METHODS: Medical records of pediatric patients with confirmed tracheal rings on bronchoscopy who underwent slide tracheoplasty between January 2001 and December 2015 were reviewed. Patients who had operative notes documenting tracheal sizing over time were included. Exclusion criteria included tracheal stenosis not caused by complete tracheal rings, surgical repair prior to presentation at our institution, or lack of adequate sizing information. The postoperative follow-up was examined and airway growth over time documented. RESULTS: Of 197 slide tracheoplasties performed during the study time period, 139 were for complete tracheal rings, and 40 of those children met inclusion criteria. The median age at time of surgery was 7 months, and the median initial airway size was 3.9 mm (n = 34). The median growth postoperatively was 1.9 mm over a median follow-up period of 57 months (0.42 mm/year), which is similar to growth rates of unrepaired complete tracheal rings (P = .53). Children underwent a median of 10 postoperative endoscopies, with time between endoscopies increasing further out from surgery. The most commonly performed adjunctive procedure was balloon dilation. CONCLUSIONS: This is the first study documenting continued growth of repaired complete tracheal rings after slide tracheoplasty. Postoperative endoscopic surveillance ensures adequate growth. Intervals between airway endoscopies can be increased as the child gets older, as the airway increases in size, and as long as symptoms are minimal.

Unrepaired Complete Tracheal Rings: Natural History and Management Considerations.

Objectives To document the natural growth pattern of unrepaired complete tracheal rings (UCTRs) and describe the patient population managed conservatively. Study Design Case series with chart review. Setting Tertiary pediatric academic center. Subjects/Methods Medical records of patients with confirmed complete tracheal rings on bronchoscopy from 1993 to 2017 were reviewed. Patients aged 0 to 18 who had documented tracheal sizing over time and did not require surgical intervention were included. Exclusion criteria included tracheal stenosis not caused by complete tracheal rings. Comorbidities and airway characteristics were documented in addition to endoscopic findings. These were compared with children requiring surgical repair. Results In total, 149 patients with complete tracheal rings were identified. Twenty-five had UCTRs for an overall 16.8% rate of conservative management. Nineteen patients met inclusion criteria and underwent a total of 90 microlaryngoscopy and bronchoscopies (MLBs) with sizing. The growth of the UCTRs over time, based on MLB sizing, was chronicled. The median airway growth noted was 0.38 mm/y. A moderately strong positive correlation was seen between age and airway size ( rs = 0.72, P < .0001). Children with UCTRs were less likely to have long-segment involvement than those who required repair (92%, P = .024). Conclusions A select group of children with complete tracheal rings can be managed expectantly without surgical intervention. Conservative management may be less successful in children with long-segment complete tracheal rings. Airway growth does occur in this population and can be monitored over time. Having a standardized method for sizing UCTRs allows for more effective communication between providers and assurance of continued growth of the airway while following these patients.

Stochastic multistationarity in a model of the hematopoietic stem cell differentiation network.

A central issue in the analysis of multi-stable systems is that of controlling the relative size of the basins of attraction of alternative states through suitable choices of system parameters. We are interested here mainly in the stochastic version of this problem, that of shaping the stationary probability distribution of a Markov chain so that various alternative modes become more likely than others. Although many of our results are more general, we were motivated by an important biological question, that of cell differentiation. In the mathematical modeling of cell differentiation, it is common to think of internal states of cells (quanfitied by activation levels of certain genes) as determining the different cell types. Specifically, we study here the "PU.1/GATA-1 circuit" which is involved in the control of the development of mature blood cells from hematopoietic stem cells (HSCs). All mature, specialized blood cells have been shown to be derived from multipotent HSCs. Our first contribution is to introduce a rigorous chemical reaction network model of the PU.1/GATA-1 circuit, which incorporates current biological knowledge. We then find that the resulting ODE model of these biomolecular reactions is incapable of exhibiting multistability, contradicting the fact that differentiation networks have, by definition, alternative stable steady states. When considering instead the stochastic version of this chemical network, we analytically construct the stationary distribution, and are able to show that this distribution is indeed capable of admitting a multiplicity of modes. Finally, we study how a judicious choice of system parameters serves to bias the probabilities towards different stationary states. We remark that certain changes in system parameters can be physically implemented by a biological feedback mechanism; tuning this feedback gives extra degrees of freedom that allow one to assign higher likelihood to some cell types over others.

Outcomes of Drug-Induced Sleep Endoscopy-Directed Surgery for Pediatric Obstructive Sleep Apnea.

Objectives To determine the effectiveness of pediatric drug-induced sleep endoscopy (DISE)-directed surgery for children with infant obstructive sleep apnea (OSA) or OSA after adenotonsillectomy. Study Design Case series with chart review. Setting Tertiary care pediatric hospital. Subjects and Methods We included 56 children undergoing DISE from October 2013 to September 2015 who underwent subsequent surgery to address OSA. The primary outcome was successful response to DISE-directed surgery based on the postoperative obstructive Apnea-Hypopnea Index (oAHI). Wilcoxon matched-pairs signed-ranks tests were used to compare polysomnography variables before and after surgery, and regression was used to model response to surgery. Results We evaluated 56 patients with a mean age of 5.9 ± 5.5 years (range, 0.1-17.4) and mean body mass index of 21.2 ± 7.9 kg/m2 (percentile, 77 ± 30). The most commonly performed surgical procedures were adenoidectomy (48%, n = 27), supraglottoplasty (38%, n = 21), tonsillectomy (27%, n = 15), lingual tonsillectomy (13%, n = 7), nasal surgery (11%, n = 6), pharyngoplasty (7%, n = 4), and partial midline glossectomy (7%, n = 4). Mean oAHI improved from 14.9 ± 13.5 to 10.3 ± 16.2 events/hour, with 54% (30 of 56) of children with oAHI <5 and 16.1% (9 of 56) with oAHI <1. There was a significant improvement in oAHI ( P = .001) and saturation nadir ( P < .001) but not in time with end tidal carbon dioxide >50 mm Hg ( P = .14). Multivariable modeling, controlling for age, race, body mass index, sex, and baseline polysomnography variables, revealed that white race predicted success of DISE-directed surgery. Conclusion Fifty-four percent of children with infant OSA or persistent OSA after adenotonsillectomy had oAHI <5 events per hour after DISE-directed surgery. Only white race was predictive of oAHI <5 events per hour.

Trends in childhood pneumococcal vaccine coverage in Shanghai, China, 2005-2011: a retrospective cohort study.

BACKGROUND: In China, the pneumococcal conjugate vaccine (PCV7) and the pneumococcal polysaccharide vaccine (PPSV23) are not offered under the government's Expanded Program on Immunization and are instead administered for a fee. PCV7 is more effective and covers more serotypes associated with invasive disease in children, but is also more expensive, than PPSV23. Because of their expense, there is concern that these vaccines, especially PCV7, have low uptake particularly among non-locals, migrants from outside of Shanghai. This paper characterizes the differential coverage of PCV7 and PPSV23 between locals and non-locals in Shanghai, and illustrates coverage trends over time. METHODS: In this retrospective cohort study, children born between 2005 and 2011 were sampled from the Shanghai Immunization Program Information System. Bivariate and multivariable analyses examined the relationships between demographic characteristics, residency status (non-locals vs locals), and vaccination coverage. RESULTS: PPSV23 coverage (29.8 %) among children over 2 years of age was higher than PCV7 coverage (10.1 %) for locals and non-locals. Uptake of PCV7 increased substantially after children were 2 years of age. Overall, non-local populations had higher PPSV23 coverage (OR: 1.34; 98 % CI: 1.22, 1.46) but lower PCV7 coverage (OR: 0.617, 98 % CI: 0.547, 0.695) than locals. CONCLUSIONS: There is a need for increasing overall pneumococcal coverage in Shanghai children, particularly with the more effective PCV7 vaccine. Morbidity and mortality due to invasive pneumococcal disease for children <1 year of age are unlikely to be mitigated if the current age-related vaccination patterns are not improved.

Mandibular facial talon cusp: a rare case report.

Talon cusp (TC) is a relatively uncommon developmental anomaly characterized by cusp-like projections from the cemento-enamel junction to a variable distance toward the incisal edge of an anterior tooth. It usually presents on palatal/lingual surface of the anterior teeth. Studies have revealed that it consists of enamel, dentine and a variable amount of pulp tissue. Presence of this cusp on the facial surface of an anterior tooth is a rare finding with very few cases being reported in the literature. The effects of TCs are mainly aesthetic and functional. The management requires a sufficient knowledge of the present clinical entity and the problems associated with it. Early detection and treatment plays a very vital role in avoiding the future complications. The present case reports a 25-year-old male patient with a facial TC on the mandibular left central incisor in which a prophylactic enameloplasty was carried out to avoid the stagnation of debris and stain.