Otolaryngology–Head and Neck Surgery

The use of endoscopic approaches for sinonasal malignancy resection has increased, but survival data are limited secondary to disease rarity and new surgical technique. Here we present a systematic review and meta-analysis of endoscopic endonasal resection of sinonasal malignancy.

MEDLINE, PubMed Central, NCBI Bookshelf, Cochrane Library, clinicaltrials.gov, National Guideline Clearinghouse.

PRISMA/MOOSE guidelines were followed. MeSH terms were “endoscopic” AND (“esthesioneuroblastoma” OR “sinonasal adenocarcinoma” OR “squamous cell carcinoma” OR “sinonasal undifferentiated carcinoma”). For studies in which individual-level data were available, results were obtained by direct pooling. For studies in which only summary Kaplan-Meier curves were available, numerical data were extracted, traced, and aggregated by fitting a Weibull model.

Of 320 studies identified, 35 case series were included (n = 952 patients), with 15 studies analyzed via aggregate modeling and 20 studies analyzed via direct pooling. Two- and 5-year survival rates for patients in aggregate modeling were 87.5% and 72.3%, respectively (mean follow-up: 32.9 months). Two- and 5-year survival for patients in direct pooling were 85.8% and 83.5%, respectively (mean follow-up: 43.0 ± 19.5 months). Significant overall survival difference was found between low- and high-grade cancers (P = .015) but not between low- and high-stage cancers (P = .79).

Overall 2- and 5-year survival rates are comparable and sometimes greater than those from open craniofacial resection. Survival rates significantly differ by cancer grade but not stage. Journals and investigators should be encouraged to publish retrospective and prospective case series with staged survival updates based on established guidelines.

The orbital blowout fracture is a common facial injury, carrying with it a risk of visual impairment and undesirable cosmetic results unless treated properly. Optimal timing of the surgical treatment is still a matter of debate. We set out to determine whether a meta-analysis would bring us closer to an answer to this question.

PubMed, EMBASE, Web of Science, and the Cochrane Library were searched from January 1980 to August 2014. We applied the following inclusion criteria: isolated blowout fractures, presenting early and late surgery groups (<14 and >14 days). Patients were evaluated for diplopia and enophthalmos.

We followed the statements of PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses). Pooled odds ratios were estimated with the fixed effects method of Mantel-Haenszel.

We identified 5 studies with available outcome data (N = 442). Patients in the late group showed an odds ratio of 3.3 (P = .027) for persistent postoperative diplopia as compared with the early group. We found no significant difference between the groups when assessing postoperative enophthalmos as an isolated symptom.

We found a significantly increased risk of persistent diplopia in patients who were operated >14 days after the trauma.

To develop a predictive model for the risk of complications after thyroid and parathyroid surgery.

Case series with planned chart review of patients undergoing surgery, 2007-2013.

Kaiser Permanente Northern California and Kaiser Permanente Southern California.

Patients (N = 16,458) undergoing thyroid and parathyroid procedures were randomly assigned to model development and validation groups. We used univariate analysis to assess relationships between each of 28 predictor variables and 30-day complication rates. We subsequently entered all variables into a recursive partitioning decision tree analysis, with P < .05 as the basis for branching.

Among patients undergoing thyroidectomies, the most important predictor variable was thyroid cancer. For patients with thyroid cancer, additional risk predictors included coronary artery disease and central neck dissection. For patients without thyroid cancer, additional predictors included coronary artery disease, dyspnea, complete thyroidectomy, and lobe size. Among patients undergoing parathyroidectomies, the most important predictor variable was coronary artery disease, followed by cerebrovascular disease and chronic kidney disease. The model performed similarly in the validation groups.

For patients undergoing thyroid surgery, 7 of 28 predictor variables accounted for statistically significant differences in the risk of 30-day complications; for patients undergoing parathyroid surgery, 3 variables accounted for significant differences in risk. This study forms the foundation of a parsimonious model to predict the risk of complications among patients undergoing thyroid and parathyroid surgery.

To identify factors associated with postoperative hypocalcemia after thyroid surgery and to understand the relationship among hypocalcemia, length of hospitalization, and costs of care.

Retrospective database analysis.

Discharge data from the Nationwide Inpatient Sample for 620,744 patients who underwent thyroid surgery from 2001 to 2010 were analyzed through cross-tabulations and multivariate regression modeling. Hypocalcemia, length of stay, and costs were examined as dependent variables. Secondary independent variables included magnesium and phosphate metabolism disorders, vitamin D deficiency, menopause, sex, extent of surgery, malignancy, and surgeon volume.

Hypocalcemia was reported in 6% of patients and was significantly more common for the following variables: women, age <65 years, patients from the Northeast, total thyroidectomy ± neck dissection patients, low-volume surgical care, malignancy, recurrent laryngeal nerve injury, and patients with disorders of magnesium or phosphate metabolism (P < .001). Magnesium and phosphate disorders were present in <1% of patients. Magnesium disorders were significantly more likely for patients with hypocalcemia (7%; P < .001), and hypocalcemia was present in 52% of patients with magnesium disorders (P < .001). On multiple logistic regression analysis, the odds of hypocalcemia were greatest for patients with magnesium disorders (odds ratio, 12.71; 95% confidence interval, 8.59-18.82). This relationship was not attenuated by high-volume surgical care. Hypocalcemia and magnesium disorders were both associated with increased length of stay and costs, with a greater effect for magnesium disorders than for hypocalcemia (P < .001).

Disorders of magnesium metabolism are an independent risk factor for postthyroidectomy hypocalcemia and are associated with significantly increased costs and length of stay.

Analyze the correlation between online-based review websites and the Press Ganey Patient Satisfaction Survey (PGPSS) in an academic otolaryngology department.

Retrospective cross sectional.

Tertiary academic institution.

All available data were collected for Vitals.com and Healthgrades.com, along with PGPSS data for 16 otolaryngology attending physicians from 2012 to 2014. A mean rating was calculated for each topic category for online websites and compared with 7 PGPSS content questions using zero-order correlations. A paired t test was used to analyze the difference between the PGPSS and online scores.

There were no statistically significant correlations between time spent with the patient (r = 0.391, P = .208) and overall provider scores (r = 0.193, P = .508) when compared between Vitals.com and the PGPSS. The correlations were not statistically significant when Healthgrades.com was compared with the PGPSS in the items “probability of recommending the provider” (r = −0.122, P = .666) and “trust in provider” (r = −0.025, P = .929). The most important factors in a patient recommending the provider were as follows, per resource: time spent with the patient for Vitals.com (r = 0.685, P = .014), listening for Healthgrades.com (r = 0.981, P ≤ .001), and trust in the provider for the PGPSS (r = 0.971, P ≤ .001).

This study suggests that online-based reviews do not have statistically significant correlations with the widely used PGPSS and may not be an accurate source of information for patients. Patients should have access to the most reliable and least biased surveys available to the public to allow for better-informed decisions regarding their health care.

(1) Reanalyze publicly available genomic data for HPV-negative oral cavity squamous cell carcinoma to look for candidate biomarkers. (2) Evaluate the association of the identified biomarkers with survival.

Retrospective cohort study.

Tertiary care.

Gene expression barcode analysis was applied to an existing publicly available data set of 54 HPV-negative oral cavity squamous cell carcinoma tumor samples to identify candidate genes associated with poor prognosis. Genes identified were evaluated for their association with survival on the basis of univariable and multivariable Cox proportional hazards models.

Three genes were found to be associated with poor prognosis. The most significant association was seen with spectrin expression. Subjects whose tumors expressed spectrin were 4.60 times more likely (hazard ratio; 95% confidence interval: 1.88-11.25) to die at any given time when compared with those without spectrin (P = .001). On univariable analysis, subjects with late-stage cancer were 6.34 times more likely (hazard ratio; 95% confidence interval: 1.41-28.53; P = .02) to die at any given time, but interestingly, after controlling for spectrin, this effect was attenuated (P = .07). Despite controlling for several possible confounding effects, the effect of spectrin remained hazardous throughout all multivariable models. This was true even after controlling for cancer stage and extracapsular extension (P = .004).

Our analysis of public genomic data shows promise in identifying biomarkers that may allow clinicians to make more accurate survival predictions. Spectrin is a strong candidate for further biomarker testing.

The present study was conducted to determine the preventive efficacy of vitamin C/E complex supplementation for radiotherapy (RT)–induced xerostomia in patients with head and neck cancer.

Prospective, double-blinded, randomized, placebo-controlled study.

A single tertiary referral institution.

The trial group (n = 25) received antioxidant supplements (100 IU of vitamin E + 500 mg of vitamin C) twice per day during RT, while the control group (n = 20) received an identical placebo. Pre-RT and 1 and 6 months post-RT, patient-reported xerostomia questionnaires, observer-rated xerostomia score, and salivary scintigraphy were serially obtained to compare xerostomia severity between the 2 groups.

The trial group showed greater improvements in xerostomia questionnaire and score at 6 months post-RT when compared with those at 1 month post-RT (P = .007 and .008, respectively). In contrast, the control group showed no changes between 1 and 6 months post-RT. By salivary scintigraphy, there was no difference in maximal accumulation or ejection fraction between the 2 groups. However, the trial group maintained significantly better oral indices at the prestimulatory (P = .01) and poststimulatory (P = .009) stages at 1 month post-RT, compared with the control group. At the final follow-up, there was no difference in overall survival and disease-free survival between the 2 groups.

Our data suggest that short-term supplementation with an antioxidant vitamin E/C complex exerts a protective effect against RT-induced xerostomia.

To assess the diagnostic accuracy of fine-needle aspiration (FNA) of the parotid and submandibular glands.

Case series with chart review.

Tertiary referral academic center.

Retrospective analysis was performed for all parotid and submandibular gland FNAs from a single center from 2001 to 2014. There were 1283 FNAs performed for 1076 patients. Of these, 343 cases had surgical follow-up (parotid gland, n = 272; submandibular gland, n = 71). Cases were included where the patient had a preoperative FNA, followed by surgical excision. Correlation of preoperative FNA results to final surgical pathology was performed, with measures of diagnostic accuracy computed.

Malignancy was identified in 29.0% of parotid tumors and 42.3% of submandibular tumors, based on final pathology. FNA was nondiagnostic due to insufficient cellularity for evaluation in 22 of 343 cases (6.4%) and indeterminate in 39 of 343 cases (11.4%). Diagnostic accuracy in the parotid and submandibular glands for distinguishing benign from malignant pathology was determined as follows, respectively: sensitivity, 75.0% and 91.3%; specificity, 95.1% and 94.1%; positive predictive value, 84.9% and 91.3%; and negative predictive value, 91.2% and 94.4%.

FNA has high accuracy in identifying malignancy in parotid and submandibular gland lesions when performed at a high-volume center. Preoperative FNA results provide otolaryngologists with valuable diagnostic information that may influence the surgical management of salivary gland tumors. FNA, in conjunction with cross-sectional imaging, is useful in counseling patients for a complete informed consent.

To determine the variables that are predictive of failed decannulation (FD), delayed decannulation (DD), and days to decannulation in patients who underwent head and neck cancer resection with free tissue transfer reconstruction for head and neck squamous cell carcinoma.

Case series with chart review.

Tertiary care otolaryngology–head and neck surgery referral center.

Patients (N = 108) were included who underwent head and neck cancer resection with free tissue transfer reconstruction and tracheostomy between 2011 and June 2014. Patients with laryngectomy, previous tracheostomy, and other airway pathology necessitating tracheotomy were excluded. Preoperative patient variables and cancer site/staging variables were analyzed, as well as extent of structures resected and type of reconstruction. Univariate and multivariate binary logistic and Cox regression analyses were used to determine predictors of FD and DD. Cox regression analysis was used to determine predictors of days to decannulation.

Of the 108 included patients, 16 had FD, and 26 had DD. Univariate analysis demonstrated that advanced stage (r = 0.233, P = .021), total glossectomy (r = 0.924, P < .001), anterolateral thigh flap reconstruction (r = 0.906, P < .001), smoking at time of surgery (r = 0.319, P = .002), and pack years (r = 0.322, P = .001) were associated with FD. Cox regression analysis showed that total glossectomy, exp(B) = 15.837 (95% confidence interval [95% CI]: 1.949-128.679); anterolateral thigh flap reconstruction, exp(B) = 8.439 (95% CI: 2.435-29.620); and smoking status, exp(B) = 2.970 (95% CI: 1.617-5.456) were independent predictors of days to decannulation and FD.

Patients with total glossectomy defects and those who continue to smoke are at increased risk for FD and DD. Aggressive smoking cessation programs may decrease the risk of FD and DD. Patients should be counseled about their risk profiles.

Early differentiation of patients with unilateral vocal fold paralysis (VFP) who recover from those who do not and consequently require permanent medialization laryngoplasty (ML) remains a challenge. The goal of this study is to identify factors that predict the need for ML.

Case series with chart review.

Academic center.

A total of 507 records of patients with VFP were analyzed, of which 252 met criteria and were stratified according to whether or not they obtained ML. Demographic information and clinical features were analyzed to determine predictors of ML. A nomogram was generated according to the significance and utility of these parameters.

Of 252 patients, 86 underwent ML, and 166 did not. No differences in age or sex were observed between the ML and non-ML patients (P = .27 and P = .35, respectively). The most common cause of VFP was iatrogenic injury (62.79%, ML; 49.40%, non-ML). ML correlated with VFP secondary to neoplastic disease (odds ratio [OR], 2.14; 95% confidence interval [95% CI], 1.01-4.53) and iatrogenic injury (OR 1.73; 95% CI 1.01-2.94). ML had an inverse correlation with idiopathic VFP (OR, 0.40; 95% CI, 0.20-0.79). Patients in the ML group were more likely to have left-sided VFP, to have a history of aspiration, and to present ≥90 days from onset and less likely to have had temporary injection augmentation.

Clinical features may be used to predict the likelihood of a patient obtaining ML. Nomograms may be useful to counsel patients who would benefit from early definitive surgery.

The effect of vocal fold medialization (VFM) on vocal improvement in persons with unilateral vocal fold immobility (UVFI) is well established. The effect of VFM on the symptom of dysphagia is uncertain. The purpose of this study is to evaluate dysphagia symptoms in patients with UVFI pre- and post-VFM.

Case series with chart review.

Academic tertiary care medical center.

The charts of 44 persons with UVFI who underwent VFM between June 1, 2013, and December 31, 2014, were abstracted from a prospectively maintained database at the University of California, Davis, Voice and Swallowing Center. Patient demographics, indications, and type of surgical procedure were recorded. Self-reported swallowing impairment was assessed with the validated 10-item Eating Assessment Tool (EAT-10) before and after surgery. A paired samples t test was used to compare pre- and postmedialization EAT-10 scores.

Forty-four patients met criteria and underwent either vocal fold injection (73%) or thyroplasty (27%). Etiologies of vocal fold paralysis were iatrogenic (55%), idiopathic (29%), benign or malignant neoplastic (9%), traumatic (5%), or related to the late effects of radiation (2%). EAT-10 (mean ± SD) scores improved from 12.2 ± 11.1 to 7.7 ± 7.2 after medialization (P < .01) with a follow-up of 119 ± 65 days.

Patients with UVFI suffer from dysphagia and report significant improvement in swallowing symptoms following VFM. The symptomatic improvement appears to be durable over time.

Previous research has shown that office-based laryngoscopic procedures can induce hemodynamic changes, including tachycardia and severe hypertension, calling into question the safety of these procedures. However, comparison between office and operating room (OR) procedures has not been carried out. Therefore, we prospectively measured hemodynamic variables in both settings to compare hemodynamic changes between office and OR procedures.

Prospective cohort study.

Single academic center.

Subjects undergoing office and OR laryngoscopic procedures were prospectively identified, and 92 OR and 70 office subjects were included. Heart rate and blood pressure were measured at established time points before, during, and after the procedures. Descriptive and comparative statistical analyses were conducted.

Severe hemodynamic events, either tachycardia or severe hypertension (blood pressure >180 mm Hg systolic or >110 mm Hg diastolic), occurred significantly more frequently in OR than office procedures (41% vs 20%; P = .006). OR severe hemodynamic events occurred more commonly than previously reported rates in the office (41% vs 28%; P = .012). Regression analyses showed that the odds of having a severe hemodynamic event were 3.66 times higher in OR versus office procedures.

Severe hemodynamic events are more likely to occur in the OR than in the office during laryngologic procedures. While larger studies will be required to establish rates of dangerous cardiovascular events in laryngoscopic procedures, hemodynamic parameters indicate that office-based procedures have a safety benefit for procedures that can be conducted in either setting.

Access to hearing health care is limited in many parts of the world, creating a lack of prompt diagnosis, which further complicates treatment. The use of portable audiometry for hearing loss testing can improve access to diagnostics in marginalized populations. Our study objectives were twofold: (1) to determine the prevalence of hearing loss in children aged 4 to 11 years in Iqaluit, Nunavut, and (2) to test and demonstrate the use of our tablet audiometer as a portable hearing-testing device in a remote location.

Prospective cross-sectional observational.

Remote elementary schools in 3 Canadian Northern communities.

Tablet audiometers were used to test hearing in 218 children. Air conduction pure tones thresholds were obtained at 500, 1000, 2000, and 4000 Hz. Children with hearing loss ≥30 dB in either ear were referred for audiology services.

Tablet audiometry screening testing revealed abnormal results in 14.8% of the study participants. No significant difference in the rate of hearing loss was seen by sex; however, the rate of hearing loss decreased significantly with increasing age. The median duration of the hearing test was 5 minutes 30 seconds.

Of the study population, 14.8% tested positive for hearing loss based on our interactive tablet audiometer. In this setting, the tablet audiometer was both time efficient and largely language independent. This type of testing is valuable for providing much-needed hearing health care for high-risk populations in rural and remote areas where audiology services are often unavailable.

Melanin pigmentation is present in the human inner ear. In this study, we quantify the melanin pigmentation in the vestibular system and examine racial differences of vestibular melanin pigmentation using human cadaveric temporal bone specimens.

Basic research.

Laboratory.

Light microscopy was used to examine specimens from 40 left temporal bones from the Johns Hopkins Human Temporal Bone Collection. Color images of (1) ampulla of the horizontal canal, (2) utricular wall, (3) endolymphatic duct, and (4) posterior ampullary nerve as it enters the posterior canal were acquired with a digital camera attached to the microscope and image acquisition software. Acquired images of each anatomic area of interest were processed offline through ImageJ. Melanin content was then compared according to ethnicity, age, sex, and location.

Fifteen African American and 25 Caucasian specimens were analyzed. Mean age was 68.8 years. African American specimens had a significantly greater amount of pigment at all 4 sampled locations as compared with Caucasian specimens (P < .01). Between sexes, there was a statistically significant difference (P < .05) at the posterior ampullary nerve, with males having more than females. Melanin content was not associated with age.

There is greater melanin pigmentation within the vestibular system of African Americans than in Caucasians, similar to what has been described in the cochlea. Racial differences in vestibular physiologic function have been observed in the literature and may be explained by differences in melanin pigmentation.

To evaluate the influence of the electrode placement on hearing performance in adult patients who were simultaneously and bilaterally cochlear implanted.

Case series with planned data collection.

Tertiary referral university centers.

The postoperative computed tomography scan was studied for 19 patients who were simultaneously and bilaterally implanted with a long straight electrode array. The size of the cochlea was measured in consideration of the major cochlear diameter and cochlear height. The electrode-to-modiolus distance for the electrodes positioned at 180 and 360 degrees and the angular depth of insertion of the array were also measured. Speech perception was assessed at 1 and 5 years postimplantation with disyllabic word lists in quiet and in noise, with the speech coming from the front and a background noise (cocktail party) coming from 5 loudspeakers.

At 1 year postimplantation, the electrode-to-modiolus distance at 180 degrees was correlated with the speech perception scores in both quiet and noise. In patients with a full electrode insertion, no correlation was found between the angular depth of insertion and hearing performance. The speech perception scores in noise gradually declined as a function of the number of inserted and active electrodes. No relationship between electrode position and speech perception scores was found at 5 years postimplantation.

In adult patients who were simultaneously and bilaterally implanted, the use of a long straight array, the full electrode array insertion, and the proximity to the modiolus might be determining factors to obtain the best speech performance at 1 year, without influence on the speech perception scores after long-term use.

To evaluate the histopathologic changes of dark, transitional, and hair cells of the vestibular system in human temporal bones from patients with chronic otitis media.

Comparative human temporal bone study.

Otopathology laboratory.

To compare the density of vestibular dark, transitional, and hair cells in temporal bones with and without chronic otitis media, we used differential interference contrast microscopy.

In the chronic otitis media group (as compared with the age-matched control group), the density of type I and type II hair cells was significantly decreased in the lateral semicircular canal, saccule, and utricle (P < .05). The density of type I cells was also significantly decreased in the chronic otitis media group in the posterior semicircular canal (P = .005), but that of type II cells was not (P = .168). The mean number of dark cells was significantly decreased in the chronic otitis media group in the lateral semicircular canal (P = .014) and in the posterior semicircular canal (P = .002). We observed no statistically significant difference in the density of transitional cells between the 2 groups (P > .1).

The findings of our study suggest that the decrease in the number of vestibular sensory cells and dark cells could be the cause of the clinical symptoms of imbalance of some patients with chronic otitis media.

To examine the sensitivity and specificity of history, physical examination, and radiologic studies as predictors of foreign body aspiration in children.

Case series with chart review.

Tertiary care children’s hospital.

Medical records were reviewed for 102 children who presented to our institution from 2006 to 2013 with suspected foreign body aspiration and who underwent endoscopy. Data included symptoms, physical examination, radiologic, and endoscopy findings. Descriptive statistics, sensitivity and specificity, and univariate and multivariable analyses were performed.

A total of 102 patients were included (62% male). The mean age was 3.3 years (SD, 3.7). A foreign body was identified on endoscopy in 69 cases (68%). The most common presenting symptoms were cough (88%), choking/gagging (67%), and wheezing (57%). Decreased breath sounds and wheezing on examination were independently associated with increased odds of foreign body. The most common abnormal radiographic finding was air trapping (33%). The most frequent items retrieved were fragments of seeds and nuts (49%). There were no serious complications related to endoscopy. The sensitivity and specificity of any finding on history, physical examination, and imaging were 100% and 3%, 90% and 33%, 61% and 77%, respectively. Having a positive history, examination, and chest radiograph combined was 46% sensitive and 79% specific.

Patients with airway foreign bodies have varied presentations. The presence of any radiologic finding suggests that endoscopy should be performed, as a foreign body is probable. The absence of any history or physical examination finding was associated with a low likelihood of a foreign body.

To determine the effect of ibuprofen on posttonsillectomy bleeding when compared with codeine in posttonsillectomy analgesia.

Case series with chart review.

Tertiary care children’s hospital, Philadelphia, Pennsylvania.

On July 1, 2012, our institution transitioned from acetaminophen with codeine to ibuprofen for posttonsillectomy analgesia. Pediatric patients (0-18 years old) who underwent surgery from July 1, 2010, to June 30, 2012, were placed in the codeine cohort, and those who underwent surgery from July 1, 2012, to June 30, 2014, were placed in the ibuprofen cohort.

A total of 6014 patients underwent tonsillectomy between July 1, 2010, and June 30, 2014, and 211 patients presented for posttonsillectomy hemorrhage during the same period. The incidence of readmission for posttonsillectomy hemorrhage was 3.4% and 3.6% (P = .63; odds ratio [OR] = 1.07; 95% confidence interval [95% CI]: 0.811-1.410) for the codeine and ibuprofen groups, respectively, and the incidence of second operation for control of posttonsillectomy bleeding for the codeine and ibuprofen groups was 1.9% and 2.2% (P = .54; OR = 1.117; 95% CI: 0.781-1.600), respectively. Patients aged 11 to 18 years demonstrated a higher incidence of posttonsillectomy bleeding events overall. When age is controlled, multivariate logistic regression demonstrated no statistically significant increase in posttonsillectomy bleeding events among pediatric patients treated with ibuprofen versus patients treated with codeine (readmission: P = .617; OR = 0.932; 95% CI: 0.707-1.228; reoperation: P = .513; OR = 0.887; 95% CI: 0.618-1.272).

Age is an independent risk factor for posttonsillectomy bleeding. When age is controlled, there is no statistically significant increase in the incidence of posttonsillectomy bleeding events among patients treated with ibuprofen when compared to patients treated with codeine.

This computational study aims to (1) use virtual surgery to theoretically investigate the maximum possible change in nasal aerodynamics after turbinate surgery, (2) quantify the relative contributions of the middle and inferior turbinates to nasal resistance and air conditioning, and (3) quantify to what extent total turbinectomy impairs the nasal air-conditioning capacity.

Virtual surgery and computational fluid dynamics.

Academic tertiary medical center.

Ten patients with inferior turbinate hypertrophy were studied. Three-dimensional models of their nasal anatomies were built according to presurgery computed tomography scans. Virtual surgery was applied to create models representing either total inferior turbinectomy (TIT) or total middle turbinectomy (TMT). Airflow, heat transfer, and humidity transport were simulated at a steady-state inhalation rate of 15 L/min. The surface area stimulated by mucosal cooling was defined as the area where heat fluxes exceed 50 W/m².

In both virtual total turbinectomy models, nasal resistance decreased and airflow increased. However, the surface area where heat fluxes exceed 50 W/m² either decreased (TIT) or did not change significantly (TMT), suggesting that total turbinectomy may reduce the stimulation of cold receptors by inspired air. Nasal heating and humidification efficiencies decreased significantly after both TIT and TMT. All changes were greater in the TIT models than in the TMT models.

TIT yields greater increases in nasal airflow but also impairs the nasal air-conditioning capacity to a greater extent than TMT. Radical resection of the turbinates may decrease the surface area stimulated by mucosal cooling.

To directly measure the spatial mapping in the olfactory bulb by odor presentation and by direct electrical stimulation.

Experimental (animal).

University research laboratory.

Odor (n = 8) and electrical stimulation (n = 4) of the olfactory bulb in rats were used to demonstrate the spatial mapping of neural responses in the olfactory bulb. Both multiunit responses to odor stimulation and evoked potential responses to localized electrical stimulation were measured in different regions of the olfactory bulb.

Responses that were recorded simultaneously from an array of 32 electrodes positioned at different locations within the olfactory bulb were mapped. Results show different spatial patterns of neural activity for different odors (odor maps). Direct stimulation of the olfactory bulb with electrical current pulses from electrodes positioned at different locations was also effective in generating spatial patterns of neural activity.

These data suggest that by programming an array of stimulating electrodes, it should be possible to selectively activate different regions of the olfactory bulb, generating unique patterns of neural activity as seen in normal smell.