Sachin S. Pawar

Toward personalized nasal surgery using computational fluid dynamics.

OBJECTIVE To evaluate whether virtual surgery performed on 3-dimensional (3D) nasal airway models can predict postsurgical, biophysical parameters obtained by computational fluid dynamics (CFD). METHODS Presurgery and postsurgery computed tomographic scans of a patient undergoing septoplasty and right inferior turbinate reduction (ITR) were used to generate 3D models of the nasal airway. Prior to obtaining the postsurgery scan, the presurgery model was digitally altered to generate 3 virtual surgery models: (1) right ITR only, (2) septoplasty only, and (3) septoplasty with right ITR. The results of the virtual surgery CFD analyses were compared with postsurgical CFD outcome measures including nasal resistance, unilateral airflow allocation, and regional airflow distribution. RESULTS Postsurgery CFD analysis and all virtual surgery models predicted similar reductions in overall nasal resistance, as well as more balanced airflow distribution between sides, primarily in the middle region, when compared with the presurgery state. In contrast, virtual ITR alone produced little change in either nasal resistance or regional airflow allocation. CONCLUSIONS We present an innovative approach for assessing functional outcomes of nasal surgery using CFD techniques. This preliminary study suggests that virtual nasal surgery has the potential to be a predictive tool that will enable surgeons to perform personalized nasal surgery using computer simulation techniques. Further investigation involving correlation of patient-reported measures with CFD outcome measures in multiple individuals is under way.

Computed nasal resistance compared with patient-reported symptoms in surgically treated nasal airway passages: a preliminary report.

Background Nasal airway obstruction (NAO) is a common health condition impacting mood, energy, recreation, sleep, and overall quality of life. Nasal surgery often addresses NAO but the results are sometimes unsatisfactory. Evaluating surgical treatment efficacy could be improved if objective tests were available that correlated with patient-reported measures of symptoms. The goal of this study was to develop methods for comparing nasal resistance computed by computational fluid dynamics (CFD) models with patient-reported symptoms of NAO using early data from a 4-year prospective study. Methods Computed tomography (CT) scans and patient-reported scores from the Nasal Obstruction Symptom Evaluation (NOSE) scale and a visual analog scale (VAS) measuring unilateral airflow sensation were obtained pre- and postoperatively in two NAO patients showing no significant mucosal asymmetry who were successfully treated with functional nasal surgery, including septoplasty. Pre- and postsurgery CFD models were created from the CT scans. Numerical simulation of steady-state inspiratory airflow was used to calculate bilateral and unilateral CFD-derived nasal resistance (CFD-NR). Results In both subjects, NOSE and VAS scores improved after surgery, bilateral CFD-NR decreased, and unilateral CFD-NR decreased on the affected side. In addition, NOSE and VAS scores tracked with unilateral CFD-NR on the affected side. Conclusion These preliminary results suggest a possible correlation between unilateral NR and patient-reported symptoms and imply that analysis of unilateral obstruction should focus on the affected side. A formal investigation of unilateral CFD-NR and patient-reported symptoms in a series of NAO patients is needed to determine if these variables are correlated.BACKGROUND Nasal airway obstruction (NAO) is a common health condition impacting mood, energy, recreation, sleep, and overall quality of life. Nasal surgery often addresses NAO but the results are sometimes unsatisfactory. Evaluating surgical treatment efficacy could be improved if objective tests were available that correlated with patient-reported measures of symptoms. The goal of this study was to develop methods for comparing nasal resistance computed by computational fluid dynamics (CFD) models with patient-reported symptoms of NAO using early data from a 4-year prospective study. METHODS Computed tomography (CT) scans and patient-reported scores from the Nasal Obstruction Symptom Evaluation (NOSE) scale and a visual analog scale (VAS) measuring unilateral airflow sensation were obtained pre- and postoperatively in two NAO patients showing no significant mucosal asymmetry who were successfully treated with functional nasal surgery, including septoplasty. Pre- and postsurgery CFD models were created from the CT scans. Numerical simulation of steady-state inspiratory airflow was used to calculate bilateral and unilateral CFD-derived nasal resistance (CFD-NR). RESULTS In both subjects, NOSE and VAS scores improved after surgery, bilateral CFD-NR decreased, and unilateral CFD-NR decreased on the affected side. In addition, NOSE and VAS scores tracked with unilateral CFD-NR on the affected side. CONCLUSION These preliminary results suggest a possible correlation between unilateral NR and patient-reported symptoms and imply that analysis of unilateral obstruction should focus on the affected side. A formal investigation of unilateral CFD-NR and patient-reported symptoms in a series of NAO patients is needed to determine if these variables are correlated.

Objective measures in aesthetic and functional nasal surgery: perspectives on nasal form and function.

The outcomes of aesthetic and functional nasal surgery are difficult to assess objectively because of the intricate balance between nasal form and function. Despite historical emphasis on patient-reported subjective measures, objective measures are gaining importance in both research and the current outcomes-driven health care environment. Objective measures currently available have several shortcomings that limit their routine clinical use. In particular, the low correlation between objective and subjective measures poses a major challenge. However, advances in computer, imaging, and bioengineering technology are now setting the stage for the development of innovative objective assessment tools for nasal surgery that can potentially address some of the current limitations. Assessment of nasal form after aesthetic surgery is evolving from two-dimensional analysis to more sophisticated three-dimensional analysis. Similarly, assessment of nasal function is evolving with the introduction of computational fluid dynamics techniques, which allow for a detailed description of the biophysics of nasal airflow. In this article, we present an overview of objective measures in both aesthetic and functional nasal surgery and discuss future trends and applications that have the potential to change the way we assess nasal form and function.

Treatment of postnasal drip with proton pump inhibitors: a prospective, randomized, placebo-controlled study.

Background Patients commonly present with complaints of postnasal drainage (PND) without objective evidence to support a sinonasal or infectious etiology. PND has been attributed to extra-esophageal reflux (EER), and an empiric trial of antireflux medication often is used to treat PND and associated symptoms. This study was performed to (1) evaluate the relationship between symptoms of EER and PND and (2) assess the efficacy of proton pump inhibitors (PPIs) in the management of PND. Methods Patients with a chief complaint of PND without objective evidence of sinonasal inflammatory disease were enrolled in a prospective, double-blinded, randomized placebo-controlled trial using rabeprazole, 20 mg, orally twice daily or placebo for 90 days. Subjects completed two-site 24-hour pharyngeal pH probe monitoring before treatment. Outcome measures included pre- and posttreatment visual analog scales for PND symptoms, reflux symptom index, and reflux finding score (RFS). Results Forty-seven patients were enrolled (mean age, 55 years)—21 patients in the PPI group and 26 in the placebo group. Fifty-six percent of subjects had pH probe confirmed EER using a cutoff of pH < 5.0. Baseline symptom measures between subjects with and without EER were not different. Compared with placebo, subjects receiving rabeprazole reported significant reduction in PND frequency (p = 0.0180), hoarseness (p = 0.0164), and chronic cough (p = 0.0204). The RFS decreased slightly in the placebo group (p = 0.1490) whereas it increased slightly in the PPI group (p = 0.5235). This difference between groups was significant (p = 0.0272). Conclusion Although 50% of subjects had evidence of EER, there was no difference in baseline symptoms between subjects with and without. Our findings support the potential benefit of PPI therapy for reducing PND frequency, hoarseness, and chronic cough, and confirm a placebo effect for other laryngopharyngeal reflux symptoms. The effect on laryngeal findings is mixed and patients may experience symptomatic improvement before changes in laryngoscopic appearance.

Effects of Anatomy and Particle Size on Nasal Sprays and Nebulizers

Objective. To study the effects of nasal deformity on aerosol penetration past the nasal valve (NV) for varying particle sizes using sprays or nebulizers. Study Design. Computed mathematical nasal airway model. Setting. Department computer lab. Subjects and Methods. Particle deposition was analyzed using a computational fluid dynamics model of the human nose with leftward septal deviation and compensatory right inferior turbinate hypertrophy. Sprays were simulated for 10 µm, 20 µm, 50 µm, or particle sizes following a Rosin Rammler particle size distribution (10-110 µm), at speeds of 1, 3, or 10 meters per second. Nebulization was simulated for 1, 3.2, 6.42, or 10 µm particles. Steady state inspiratory airflow was simulated at 15.7 liters per minute. Results. Sprays predicted higher NV penetration on the right side for particle sizes >10 µm, with comparable penetration on both sides at 10 µm. Nearly 100% deposited in the nasal passages for all spray characteristics. Nebulizer predictions showed nearly 100% of particles <6.42 µm and more than 50% of 6.42 µm bypassing both sides of the nose without depositing. Of the nebulized particles that deposited, penetration was higher on the right at 10 µm, with comparable penetration on both sides at 6.42 µm. Spray penetration was highest at 10 µm, with more than 96% penetrating on both sides at 1 and 3 meters per second. Nebulization penetration was also highest at 10 µm (40% on the left, >90% on the right). Conclusion. In the presence of a septal deviation, sprays or nebulizers containing 10-µm particles may have good penetration beyond the NV. Nebulized particles <10 µm are likely to be respirable. Additionally, spray speeds above 3 meters per second may limit penetration.

Deviated nasal septum hinders intranasal sprays: a computer simulation study.

BACKGROUND This study investigates how deviated nasal septum affects the quantity and distribution of spray particles, and examines the effects of inspiratory airflow and head position on particle transport. METHODS Deposition of spray particles was analysed using a three-dimensional computational fluid dynamics model created from a computed tomography scan of a human nose with leftward septal deviation and a right inferior turbinate hypertrophy. Five simulations were conducted using FluentTM software, with particle sizes ranging from 20-110 μm, a spray speed of 3 m/s, plume angle of 68(deg), and with steady state inspiratory airflow either present (15.7 L/min) or absent at varying head positions. RESULTS With inspiratory airflow present, posterior deposition on the obstructed side was approximately four times less than the contralateral side, regardless of head position, and was statistically significant. When airflow was absent, predicted deposition beyond the nasal valve on the left and right sides were between 16% and 69% lower and positively influenced by a dependent head position. CONCLUSION Simulations predicted that septal deviation significantly diminished drug delivery on the obstructed side. Furthermore, increased particle penetration was associated with presence of nasal airflow. Head position is an important factor in particle deposition patterns when inspiratory airflow is absent.

Treatment of Prominent Ears and Otoplasty: A Contemporary Review

Prominent ears affect approximately 5% of the population and can have a significant psychological impact on patients. A wide variety of otoplasty techniques have been described, all sharing the goal of re-creating the normal appearance of the ear and achieving symmetry between the 2 sides. Recent trends in otoplasty techniques have consistently moved toward less invasive options, ranging from nonsurgical newborn ear molding to cartilage-sparing surgical techniques and even incisionless, office-based procedures. Herein, we review anatomy of the external ear, patient evaluation, the evolution of nonsurgical and surgical otoplasty techniques, otoplasty outcomes, and future trends for treatment of prominent ears.

Secondary Cleft Rhinoplasty

The cleft nasal deformity seen in patients with unilateral and bilateral cleft lip presents a formidable challenge for the facial plastic surgeon. The underlying anatomic deformities combined with scarring from previous procedures make secondary cleft rhinoplasty a difficult procedure for even the most experienced surgeons. Numerous techniques for secondary cleft rhinoplasty have been described in the literature over the past several decades, yet the lack of wide adoption of any given technique highlights the great variability seen with this problem. Regardless, the fundamental goals of achieving nasal symmetry with definition of the nasal base and tip, correction of nasal airway obstruction, and repair of nasal scarring or webbing have driven the progressive evolution of techniques developed to correct various aspects of the cleft nasal deformity. Despite the number of techniques that have been published, very few studies have looked specifically at outcomes in secondary cleft rhinoplasty, and further work is needed in this area. In this article, we will review anatomy of the cleft nasal deformity, repair strategies and timing, surgical techniques for both unilateral and bilateral cleft nasal deformity, and outcomes for secondary cleft rhinoplasty.

Frontal Sinus and Naso-orbital-Ethmoid Fractures

IMPORTANCE Frontal sinus and naso-orbital-ethmoid (NOE) fractures are among the most challenging injuries in the treatment of maxillofacial trauma. OBJECTIVE To summarize the current knowledge regarding frontal sinus and NOE fractures and to present some of the more recent, evidence-based literature to support current treatment recommendations. EVIDENCE REVIEW A PubMed search of articles from 1990 through 2013 was performed. Search terms included frontal sinus fracture, NOE fracture, naso-orbito-ethmoid fracture, naso-ethmoid-orbital fracture, and nasoethmoid fracture. FINDINGS Advances in sophisticated imaging and evolution in minimally invasive surgical techniques are introducing more conservative options that may provide better patient outcomes while minimizing the risks and morbidity associated with more traditional treatment approaches. CONCLUSIONS AND RELEVANCE The treatment of frontal sinus and NOE fractures is challenging, given the complex anatomy and associated pattern of injuries. Traditional treatment paradigms are evolving and support the role of more conservative treatment algorithms in selected patients.

The effect of acute pain crisis on exhaled nitric oxide levels in children with sickle cell disease

Exhaled nitric oxide (FENO) has been shown to be decreased in children with sickle cell disease. We sought to evaluate the effect of sickle cell vaso‐occlusive crisis (VOC) on FENO levels. We measured FENO levels in 42 children with sickle cell disease, 29 in their baseline health and 13 during an acute VOC. There was no difference in FENO levels between children at baseline (15.12 ± 9.32 ppb) and those during an acute VOC (15.68 ± 7.26 ppb; P = 0.794). FENO is not a useful marker of acute VOC in children with sickle cell disease. Pediatr Blood Cancer 2008;50:111–113.