A computational fluid dynamics analysis of the effects of size and shape of anterior nasal septal perforations.

BACKGROUND: Nasal septal perforations (NSPs) often cause bleeding, crusting, obstruction, and/or whistling. The objective was to analyze the impact of anterior NSP size and shape on nasal physiology using computational fluid dynamics (CFD). METHODS: A 3-dimensional model of the nasal cavity was constructed from a radiologically normal CT scan using imaging software. Anterior NSPs (ovoid (ONSP): 0.5, 1, 2, and 3 cm long anterior-to-posteriorly and round (RNSP, 0.5 and 1 cm)) were virtually created in the model and divided into ventral, dorsal, anterior, and posterior regions. Steady-state inspiratory airflow, heat, and water vapor transport were simulated using Fluent CFD software. Air crossover through the perforation, wall shear, heat flux, water vapor flux, resistance, and humidification were analyzed. RESULTS: Air crossover and wall shear increased with perforation size. Regionally, wall shear and heat and water vapor flux were highest posteriorly and lowest anteriorly, generally increasing with size in those regions. RNSPs had greater heat and water vapor flux compared to corresponding size ONSPs. Resistance decreased by 10% or more from normal only in the 3 cm ONSP. Maximum water content was achieved more posteriorly in larger NSP nasal cavities. CONCLUSIONS: High wall shear and heat and water vapor flux in posterior perforation regions may explain the crusting most commonly noted on posterior NSP edges. This preliminary study suggests that larger NSPs have a greater effect on nasal resistance and water content. Decrease in resistance with larger NSP size may be implicated in reported symptomatic improvement following enlargement of NSPs for treatment.

A computational study of functional endoscopic sinus surgery and maxillary sinus drug delivery.

BACKGROUND: Topical medication is increasingly used following functional endoscopic sinus surgery (FESS). Information on particle sizes that maximise maxillary sinus (MS) delivery is conflicting, and the effect of antrostomy size on delivery is unclear. The purpose of this study was to estimate antrostomy and particle size effects on topical MS drug delivery. METHODOLOGY: Sinonasal reconstructions were created from a pre- and a post-FESS CT scan in each of four chronic rhinosinusitis patients. Additional models were created from each post-FESS reconstruction representing four alternative antrostomy sizes. Airflow and particle deposition were simulated in each reconstruction using computational fluid dynamics for nebulised and sprayed delivery. RESULTS: MS ventilation and drug delivery increased following FESS, the largest virtual antrostomy led to greatest delivery, and MS delivery was sensitive to particle size. Particles within a 5-18 µm and 5-20 µm size range led to peak MS deposition for nebulised and sprayed particles, respectively. Post-FESS increases in drug delivery varied across individuals and within individuals by the type of antrostomy created. CONCLUSION: Our findings suggest that FESS, particularly with larger antrostomies, improves topical drug delivery, and that certain particle sizes improve this delivery. Further research is needed to contextualise these findings with other post-surgical effects.

Different cellular p16(INK4a) localisation may signal different survival outcomes in head and neck cancer.

BACKGROUND: Recently, the management of head and neck squamous cell carcinoma (HNSCC) has focused considerable attention on biomarkers, which may influence outcomes. Tests for human papilloma infection, including direct assessment of the virus as well as an associated tumour suppressor gene p16, are considered reproducible. Tumours from familial melanoma syndromes have suggested that nuclear localisation of p16 might have a further role in risk stratification. We hypothesised p16 staining that considered nuclear localisation might be informative for predicting outcomes in a broader set of HNSCC tumours not limited to the oropharynx, human papilloma virus (HPV) status or by smoking status. METHODS: Patients treated for HNSCC from 2002 to 2006 at UNC (University of North Carolina at Chapel Hill) hospitals that had banked tissue available were eligible for this study. Tissue microarrays (TMA) were generated in triplicate. Immunohistochemical (IHC) staining for p16 was performed and scored separately for nuclear and cytoplasmic staining. Human papilloma virus staining was also carried out using monoclonal antibody E6H4. p16 expression, HPV status and other clinical features were correlated with progression-free (PFS) and overall survival (OS). RESULTS: A total of 135 patients had sufficient sample for this analysis. Median age at diagnosis was 57 years (range 20-82), with 68.9% males, 8.9% never smokers and 32.6% never drinkers. Three-year OS rate and PFS rate was 63.0% and 54.1%, respectively. Based on the p16 staining score, patients were divided into three groups: high nuclear, high cytoplasmic staining group (HN), low nuclear, low cytoplasmic staining group (LS) and high cytoplasmic, low nuclear staining group (HC). The HN and the LS groups had significantly better OS than the HC group with hazard ratios of 0.10 and 0.37, respectively, after controlling for other factors, including HPV status. These two groups also had significantly better PFS than the HC staining group. This finding was consistent for sites outside the oropharynx and did not require adjustment for smoking status. CONCLUSION: Different p16 protein localisation suggested different survival outcomes in a manner that does not require limiting the biomarker to the oropharynx and does not require assessment of smoking status.

Radiofrequency tissue volume reduction: multilesion vs single-lesion treatments for snoring.

OBJECTIVE: To compare the safety and efficacy of single-lesion and multilesion radiofrequency tissue reduction (RFTR) of the soft palate for the treatment of snoring. DESIGN: Prospective, nonrandomized clinical trial. SETTING: University hospital outpatient clinic. PATIENTS: Nonrandomized patients undergoing RFTR to treat socially unacceptable snoring. Of 47 patients, 16 received single-lesion treatments and 31 received multilesion treatments. INTERVENTION: Soft-palate RFTR was performed using a radiofrequency generator. Patients required 1 to 3 treatments based on improvement or withdrawal from the study, and each received 1, 3, or 4 lesions per treatment. Patients who received single-lesion therapy did not cross over into the multilesion group; however, 5 patients in the multilesion group received 4-lesion therapy after a treatment with 3 lesions. MAIN OUTCOME MEASURES: Outcome measures were determined using visual analog scale questionnaires assessing level of snoring (snoring index) and level of pain (pain index) associated with the procedure. Adverse events and complications during treatment were cataloged. Data were collected before the procedure, 6 weeks after each treatment, and an average of 16 months after the last procedure. RESULTS: Single-lesion and multilesion groups showed significant improvement in snoring after RFTR treatments (P<.01 for both). However, compared with the single-lesion group, the multilesion group required fewer treatments (1.94 vs 2.38; P =.05) and was more than twice as likely to be cured after 2 treatments (61% vs 25%; P =.02). A trend toward improved clinical outcomes with increased number of lesions and total energy per treatment was observed when patients treated with 1, 3, or 4 lesions were compared. The 4-lesion group had the most pronounced improvement in snoring index score per treatment, the lowest number of treatments required for cure, and the greatest percentage of patients cured after 2 treatment sessions. Follow-up demonstrated minimal relapse of snoring in the multilesion group at a mean of 16 months. Although there was a statistically significant increase in pain in the multilesion group vs the single-lesion group, this increase did not increase narcotic use or time off work and was considered minimal by reporting patients. CONCLUSION: Multilesion RFTR using higher energy levels per treatment is safe and has increased efficacy without increased complications relative to single-lesion therapy.