Relation between CT scan findings and human sense of smell

Long-term olfactory dysfunction after single-nostril endoscopic transnasal transsphenoidal pituitary adenoma surgery

BACKGROUND

Over the past decade, the endoscopic transnasal transsphenoidal approach for pituitary adenomas has been widely adopted among neurosurgeons. However, olfactory disturbances have been observed after this procedure, and few studies on long-term (>6 mo) olfactory disturbance after endoscopic transnasal transsphenoidal pituitary adenoma surgery have been conducted. Although we perform minimally invasive endoscopic surgery, some patients continue to experience hyposmia, with some even experience long-term hyposmia. This impairment results in a considerable loss in quality of life. We present a series of patients who underwent minimally invasive single-nostril TSS for pituitary adenoma, including evaluation of their olfactory function. We further investigated the related risk factors for long-term olfactory dysfunction.

METHODS

One hundred sixty-one consecutive patients who met the study criteria underwent the single-nostril endoscopic transsphenoidal approach by the senior author. The Smell Diskettes Olfaction Test was used to evaluate olfactory function.

RESULTS

Postoperative olfactory disturbance in patients treated with endoscopic transnasal TSS is frequent. Of the study population, 67.1% of the patients were hyposmic or anosmic and 14.9% had long-term olfactory dysfunction. We also performed multivariate logistic regression analysis to compare the characteristics of patients with long-term olfactory dysfunction. Nasal symptoms (odds ratio [OR], 6.77) and smoking (OR, 14.77) were associated with long-term olfactory dysfunction after transnasal TSS.

CONCLUSIONS

Significant disturbances in olfactory performance occur after single-nostril transnasal TSS for pituitary adenoma. Furthermore, preoperative nasal disease and smoking appear to be risk factors for long-term olfactory dysfunction. Physicians should address clinical findings related to olfactory function and provide appropriate care.

Clinical and Radiological Evaluations of COVID-19 Patients With Anosmia: Preliminary Report

OBJECTIVES/HYPOTHESIS

To investigate clinical and radiological features of olfactory clefts of patients with mild coronavirus disease 2019 (COVID-19).

STUDY DESIGN

Prospective non controlled study.

METHODS

Sixteen COVID-19 patients were recruited. The epidemiological and clinical data were extracted. Nasal complaints were assessed through the 22-item Sino-Nasal Outcome Test. Patients underwent psychophysical olfactory testing, olfactory cleft examination, and computed tomography (CT) scans.

RESULTS

Sixteen anosmic patients were included. The mean Sniffin' Sticks score was 4.6 ± 1.7. The majority of patients had no endoscopical abnormality, with a mean olfactory cleft endoscopy score of 0.6 ± 0.9. The olfactory clefts were opacified in three patients on the CT scan. The mean radiological olfactory cleft score was 0.7 ± 0.8. There were no significant correlations between clinical, radiological, and psychophysical olfactory testing.

CONCLUSIONS

The olfactory cleft of anosmic COVID-19 patients is free regarding endoscopic examination and imaging. The anosmia etiology is not related to edema of the olfactory cleft.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:2526-2531, 2020.

Comparison of Olfactory Function and Quality of Life With Different Surgical Techniques for Nasal Septum Deviation

OBJECTIVE

To assess the nasal functions, nasal resistance, olfactory function, and quality of life in different surgical techniques for nasal septum deviation STUDY DESIGN:: Randomized controlled trial.

METHODS

This prospective controlled study was carried out on patients who underwent septoplasty. Patients participating in the study were divided into 2 groups; group 1: classic septoplasty (n: 25) and group 2: extracorporeal septoplasty (n: 14). The sinonasal outcome test-22 (SNOT-22), peak nasal flowmetry, and Connecticut Chemosensory Clinical Research Center test were applied to all patients before and 8 weeks after surgery. Surgical outcomes also assessed to evaluate complications 6 months after surgery.

RESULT

In total, 39 (27 males, 12 females) patients diagnosed with nasal septum deviation were included in this study. A septoplasty was performed in all patients: 25 of them (18 males, 7 females; mean age = 29.4 [range, 23-50] years) underwent classic septoplasties and 14 (9 males, 5 females; mean age = 31.3 [range, 23-50] years) underwent extracorporeal septoplasties. Airway openness was achieved in all patients. As a result, the SNOT-22 scores, peak nasal inspiratory flowmeter results, and smell function scores showed significant improvements (P < 0.001).

CONCLUSION

All corrective surgical methods for a septum deviation have positive effects on nasal airflow, quality of life, and olfaction. The rates of complications were not significantly different between 2 treatment groups.

The distribution of bleeding sites in idiopathic hidden arterial epistaxis

OBJECTIVE

To determine the frequency distribution of bleeding sites in idiopathic hidden arterial epistaxis.

METHODS

In this retrospective cohort study, 107 patients with hidden arterial epistaxis were endoscopically examined for sites of bleeding.

RESULTS

All sites of hidden arterial epistaxis were identified by endoscopic examination. Bleeding sites were identified at initial surgery in 103 patients and during the second surgery in 4. The bleeding sites included: the olfactory cleft region in 47 patients, the inferior meatus region in 29, the middle meatus region in 11, multiple bleeding sites (olfactory cleft and anterior septum) in 3, the anterior roof of the nasal cavity in 4, the nasal floor in 11 and the nasopharynx in 2. The bleeding points showed a white or red volcano-like bump in 75 patients, isolated prominent telangiectasia in 21 and mucosal ulceration in 11.

CONCLUSION

Common sites of hidden arterial epistaxis include the olfactory cleft, inferior meatus and middle meatus. However, there should be awareness of some uncommon bleeding sites (including the anterior roof of the nasal cavity, the nasal floor and the nasopharynx) and of multiple bleeding sites.

Correlation between olfactory function, trigeminal sensitivity, and nasal anatomy in healthy subjects

PURPOSE

Few studies have investigated the correlation between chemosensory function (trigeminal and olfactory) and nasal volume in humans, even though nasal anatomy is crucial for the sense of smell. Aim of this study was to evaluate these correlations in normosmic subjects.

METHODS

Two hundred and fifty-six healthy volunteers (age range 19-69 years) participated. Olfactory function was investigated for (the rose-like) phenylethyl alcohol odor threshold and odor identification (OI) using the Sniffin' Sticks test, while nasal structure was evaluated by acoustic rhinometry (AR); trigeminal sensitivity was assessed in terms of detection "thresholds" for the odorless carbon dioxide (CO₂).

RESULTS

There were negative correlations between olfactory sensitivity at threshold level and minimum cross-sectional area (MCSA) in both nostrils. No significant correlations were found between OI and nasal anatomy. Similar to olfactory sensitivity, with regard to the trigeminal stimulus CO₂ for the right nostril subjects were the more sensitive the smaller the MCSA.

CONCLUSIONS

The current results emphasize the significance of nasal anatomy for trigeminal/olfactory threshold perception. Interestingly, correlations were not found between suprathreshold odor identification and nasal anatomy. Other than odor identification, odor thresholds appear to depend on subtle differences in nasal anatomy.

Computed Tomography Scans in the Evaluation of Patients with Olfactory Dysfunction

Background

The necessity of computed tomography (CT) scans of the olfactory cleft and the sinuses in patients presenting with olfactory dysfunction is a matter of debate. This study aimed to investigate the significance of CT scans for the diagnosis of olfactory loss and for therapeutic decisions.

Methods

This retrospective study included 137 consecutive patients presenting with the main complaint of olfactory loss. Standardized history; ear, nose, and throat examination; and olfactory tests were administered. In addition, a CT scan of the nasal sinuses was obtained. The assumed diagnosis (sinonasal disease [SND] or non-SND) was compared with the diagnosis when additionally considering results from the CT scan.

Results

CT scans suggested SND in 7/101 patients without clinical evidence of its presence. In 12/36 patients with suspected SND-related olfactory loss, no signs of SND were detected in CT scans.

Conclusion

CT scans are useful to diagnose conductive/inflammatory olfactory loss in patients suspected of non-SND, which may then justify a course with systemic steroids. Alternatively, considering low costs and rare side effects of a short course with steroids in selected patients, CT scans appear to be of clinical significance only when surgical treatment is contemplated or where the use of systemic corticosteroids is not possible.

Lack of Significant Correlation between Rhinosinusitis Symptoms and Specific Regions of Sinus Computer Tomography Scans

Background

The sinonasal computer tomography (CT) scan is frequently used to help confirm the diagnosis of rhinosinusitis. However, little data exist correlating patient symptoms with CT findings.

Methods

Immediately preceding CT of the sinuses, 94 subjects without evidence of trauma, nasal tumors, or previous sinus surgery completed the Rhinosinusitis Outcome Measure 31 symptom questionnaire and were asked to locate areas of facial pain or pressure. CT scans were graded according to the Lund-MacKay system, and agger nasi and ethmoid bulla cells were measured. Data from CT scans and symptom/pain questionnaire responses were analyzed for significant correlations.

Results

No correlation was identified when comparing total Lund-MacKay scores, opacification of individual sinuses, and size of the agger nasi and ethmoid bulla cells with the Rhinosinusitis Outcome Measure 31 subset scores and areas of facial pain or pressure.

Conclusion

The sinus CT scan is a necessary tool for preoperative planning; however, it should not be used to predict symptoms or to localize areas responsible for facial pain or pressure.

Effects of radiofrequency and intranasal steroid treatments on respiratory and olfactory functions in nasal obstruction

OBJECTIVE

This study aimed to compare the effectiveness of radiofrequency ablation (RFA) and intranasal steroid (INS) treatments on respiratory and olfactory functions in patients with inferior concha hypertrophy and chronic nasal obstruction.

STUDY DESIGN AND SETTING

This was a prospective clinical trial performed at a tertiary referral center.

METHODS

We assessed patients with nasal obstruction between July 2011 and February 2012. The severity of the nasal obstruction in both groups was determined before treatment and 3 months after using a visual analog scale. For the purpose of an objective test, assessment was performed by the acoustic rhinometry. Using Sniffin' Sticks for test odor identification, the discrimination and thresholds were assessed in both groups.

RESULTS

The visual analog scale score after treatment was significantly lower in each group. Radiofrequency ablation treatment significantly improved the right minimal cross-sectional area 1 (MCA1), mean MCA1, and volume 1, as well as the right MCA2, mean MCA2, volume 2, and total volume. In the INS group, improvement was detected for the left MCA1, mean MCA1, and volume 1. Minimal cross-sectional area 2, volume 2, and total volume improved significantly after RFA treatment, but not after INS treatment.

CONCLUSIONS

Although RFA may be more effective in the posterior region of the nasal cavity, INS and RFA used in the treatment of inferior concha hypertrophy both had favorable effects on respiratory function. Intranasal steroid treatment provided improved discrimination and total score values, whereas RFA treatment improved only odor identification.

Olfactory function following nasal surgery

OBJECTIVE/HYPOTHESIS

This prospective study aimed to investigate predictors of nasal surgery in terms of olfactory function.

STUDY DESIGN

Prospective study.

METHODS

A total of 775 patients were included in this prospective study (482 men, 293 women; age range 10-81 years, mean age 41 years, standard deviation = 15.3 y). Prior to surgery, patients received a detailed otorhinolaryngologic examination including nasal endoscopy. Olfactory function was assessed with a standardized odor identification test ("Sniffin' Sticks"). In 356 patients, olfactory function was retested 4 months after surgery (63-339 days after surgery; mean 128 days, standard deviation = 29 days); 206 of these patients received sinus surgery, while 150 received surgery involving the septum.

RESULTS

Using a conservative definition of change of olfactory function, following sinus surgery, improvement of the sense of smell was found in 23%, no change was seen in 68%, and decreased function was seen in 9% of the patients; in patients with septum surgery, improvement was seen in 13%, no change in 81%, and decreased function in 7%. Patients exhibiting a postoperative decrease of olfactory function had significantly higher preoperative olfactory scores than patients who experienced improvement. In terms of the sense of smell, nasal surgery produced the highest success rates in patients with eosinophilia and a high degree of polyposis. Neither age nor sex had a major impact on the outcome of surgery in terms of olfactory function.

CONCLUSIONS

These results in a large group of patients confirm previous work. Apart from apparent success in 13 to 23% of patients, there is also a small but significant group of patients (7 to 9%) in whom olfactory function decreases after surgery. Because this decrease was mostly found in patients with relatively good preoperative olfactory function, this group should receive specific attention when counseling patients about the potential risks of nasal surgery.

Focal opacification of the olfactory recess on sinus CT: just an incidental finding?

BACKGROUND AND PURPOSE

The CT appearance of the anterior skull base has been investigated but with limited attention directed to the olfactory recess. As defined by opacity abutting the undersurface of the cribriform plate, the prevalence of olfactory recess opacity (ORO) on sinus CT was examined to clarify whether this should raise suspicion for an unsuspected pathologic process.

MATERIALS AND METHODS

Outpatient sinus CTs were evaluated for ORO in 500 consecutive patients (mean age, 46.9 years; 52.6% women). On a per-side basis (n = 1000), the presence of surgical changes, inflammatory sinus disease, and concha bullosa was determined by 2 neuroradiologists. Logistic regression was used to examine the association of ORO with these variables.

RESULTS

ORO was identified in 59 (11.8%) patients, bilateral in 27 (5.4%), and unilateral in 32 (6.4%). There were 343 of 1000 ethmoid sides that were diseased, and 66 (27.2%) showed ipsilateral ORO. In contrast, only 20 (3.0%) of 657 clear ethmoid sides showed ORO (P < .0001). ORO was significantly (P = .013) more common with previous surgery (18/75; 24.0%) than without (68/925; 7.4%). Ipsilateral concha bullosa was not associated with ORO. Of 32 patients with unilateral ORO, 5 (15.6%) had no ethmoid opacification or previous surgery, and 1 of these patients had an encephalocele causing the ORO. Finally, unilateral ORO was present in only 1 of 122 patients with completely clear sinuses (the encephalocele that was just mentioned).

CONCLUSION

ORO is distinctly uncommon without sinonasal inflammation or previous surgery. Isolated unilateral ORO raises suspicion for an underlying neoplasm or cephalocele and warrants further evaluation.

Inflammatory Obstruction of the Olfactory Clefts and Olfactory Loss in Humans: A New Syndrome?

The first step in the olfactory perception is the activation by odorants of sensory neurones in the olfactory epithelium. In humans, this sensory epithelium is located at 2 narrow passages, the olfactory clefts, at the upper part of the nasal cavities. Little is known about the physiology of these clefts. We examined, in 34 patients, the impact of obstructed clefts upon detection and postlearning identification of 5 odorants. The location and extension of the obstructions were assessed using endoscopy, CT scans, and MRI. The inflammatory obstruction was usually bilateral, extending anteroposteriorly, and confined to the clefts, with no sign of obstruction or any inflammatory disease in the rest of the nasal cavities and sinuses. When tested with 5 odorants, these patients showed greatly impaired olfaction compared with a group of 73 normosmic subjects. The majority of these 34 patients had sensory deficits equivalent to that found in another group of 41 congenital anosmic patients, where inspection with MRI indicated the lack of olfactory bulbs. This study demonstrates that the olfactory clefts, in human, function as an entity that is different from other regions of the nasal cavity and is the target for local inflammatory events that are apparently not responding to corticoid and antibiotic treatments.

Clinical assessment of patients with smell and taste disorders

Clinical assessment of the patient who has smell and taste disorders requires understanding of the etiology of the olfactory and gustatory disorders. Available clinical tests of olfactory and gustatory systems allow detecting and measuring the degree of the sensory loss, but are unable to determine the cause and give neither prognostic information nor therapeutic guidance. With physical examination, however, clinical history can help to establish the diagnosis and guide the treatment if available. A clinician evaluating a patient who has smell and taste loss must understand that "taste" complaints usually are symptoms of an olfactory dysfunction. The distinction between true gustatory loss (bitter, sweet, salty, sour, or umami) and olfactory loss, the inability to perceive complex flavors of food, will help clarify the patient's diagnosis. Easy-to-administer tests are available for olfactory (eg, UPSIT) and gustatory testing (eg, spatial tests, taste sticks, tasting tablets). In rare circumstances, imaging studies (eg, MRI, CT) are indicated.

Smell and taste disorders

Disorders of taste and smell can present a challenge to the facial plastic surgeon. Obtaining a detailed history and examination is the key to the diagnosis and work-up of olfactory and gustatory dysfunction. Easy-to-administer tests are available for olfactory evaluation(University of Pennsylvania Smell Identification Test) and gustatory (taste sticks, tasting tablets) evaluation. The prognosis and management of olfactory and gustatory disease depend on its etiology. Despite ongoing research, the treatment of the disorders of smell and taste is limited.

Olfactory cleft disease: an analysis of 13 cases

OBJECTIVES

Olfactory cleft disease was defined as (1) an olfactory disability related with a clinical and/or radiologic abnormality of the olfactory cleft and (2) a pathologic process limited to or predominating in the olfactory cleft. The objectives of this study were to describe the clinical and radiologic findings of this entity and to report the effect of medical therapy on the sense of smell.

STUDY DESIGN AND SETTING

Thirteen patients with the criteria of olfactory cleft disease were included in this retrospective study. All patients had bilateral olfactory cleft abnormalities. A complete ENT examination with endoscopic evaluation and a computed tomography scan were performed in all cases. An olfactory threshold test was available in 12 cases before and after medical therapy, which included oral and topically administered steroid therapy.

RESULTS

Olfactory disability was the major symptom of olfactory cleft disease. Other symptoms of chronic rhinosinus dysfunction was present in 75% of cases. Three pathologic processes were identified in patients with olfactory cleft disease: malformative, inflammatory, and inflammatory associated with anatomical deformities of olfactory cleft boundaries. Medical therapy was effective in lowering olfactory thresholds in 25% of the cases.

CONCLUSIONS AND SIGNIFICANCE

Olfactory cleft disease involves various pathophysiologic processes. Computed tomography scanning provides the most information for diagnosis. Indications of functional endoscopic surgery remain to be defined after failure of medical therapy.

Unilateral examination of olfactory threshold using the Jet Stream Olfactometer

OBJECTIVE

The Jet Stream Olfactometer, a modification by the T&T olfactometer, has been recently developed and is now commercially available. This Jet Stream Olfactometer can routinely measure the unilateral sense of smell. Clinical usefulness of the Jet Stream Olfactometer was evaluated.

METHODS

Twenty-three patients with sinus-related symptoms were examined. Unilateral olfactory acuity was examined using the Jet Stream Olfactometer and compared it with the anatomy of the olfactory cleft by computed tomographic (CT) scans.

RESULTS

In 13 of the 23 patients examined the right olfactory threshold was similar to that of the left. Of these 13, in seven patients there was transport damage of the odorants and in the other six there was sensorineural damage. Ten patients showed an apparent difference between the right and left smell thresholds. Anosmia in seven of these ten patients was due to a conductive olfactory disturbance resulting from rhinosinusitis, whereas sensorineural damage was recognized in the other three patients. The difference in the detection threshold between the right and left nasal cavities was well correlated to that of the opacity between the right and left olfactory clefts.

CONCLUSION

Jet Stream Olfactometer provides a convenient and reliable means for assessing the ability of unilateral smell.