How Does Oxymetazoline Change Nasal Aerodynamics and Symptomatology in Patients with Turbinate Hypertrophy?

OBJECTIVES

Oxymetazoline relieves nasal obstructive symptoms via vasoconstriction, however, the changes in nasal structures and aerodynamics that impact symptoms the most remain unclear.

METHODS

This prospective, longitudinal, and single blinded cohort study applied Computational Fluid Dynamic (CFD) modeling based on CT scans at baseline and post-oxymetazoline on 13 consecutive patients with chronic nasal obstruction secondary to inferior turbinate hypertrophy from a tertiary medical center. To account for placebo effect, a sham saline spray was administered with subject blindfolded prior to oxymetazoline, with 30 min rest in between. Nasal Obstruction Symptom Evaluation (NOSE) and unilateral Visual Analogue Scale (VAS) scores of nasal obstructions were collected at baseline, after sham, and 30 min after oxymetazoline.

RESULTS

Both VAS and NOSE scores significantly improved from baseline to post-oxymetazoline (NOSE: 62.3 ± 12.4 to 31.5 ± 22.5, p < 0.01; VAS: 5.27 ± 2.63 to 3.85 ± 2.59, p < 0.05), but not significantly from baseline to post-sham. The anatomical effects of oxymetazoline were observed broadly throughout the entire length of the inferior and middle turbinates (p < 0.05). Among many variables that changed significantly post-oxymetazoline, only decreased nasal resistance (spearman r = 0.4, p < 0.05), increased regional flow rates (r = -0.3 to -0.5, p < 0.05) and mucosal cooling heat flux (r = -0.42, p < 0.01) in the inferior but not middle turbinate regions, and nasal valve Wall Shear Stress (WSS r = -0.43, p < 0.05) strongly correlated with symptom improvement.

CONCLUSION

Oxymetazoline broadly affects the inferior and middle turbinates, however, symptomatic improvement appears to be driven more by global nasal resistance and regional increases in airflow rate, mucosal cooling, and WSS, especially near the head of the inferior turbinate.

LEVEL OF EVIDENCE

3: Well-designed, prospective, single blinded cohort trial. Laryngoscope, 134:1100-1106, 2024.

3D Printing as a Planning Tool to Optimize Sinonasal Irrigation

BACKGROUND

Topical sinus irrigation plays a critical role in the management of sinonasal diseases. Yet, the penetration of irrigant to targeted sinuses may be highly variable and difficult to predict. Here, we investigate the use of 3D printing as a planning tool to optimize outcomes.

METHODS

Eight post-operative models were 3D printed with a FormLabs Form3 printer based on individual CT scans. Irrigations were performed and video recorded with a squeeze bottle attached via silicon water-tight seal, in 4 head positions: 45° to-the-side, 90° to-the-side, 45° forward and 45° to-the-side, and 90° forward, with irrigation fluid entering the upper (conventional) or lower (backfill) nostrils.

RESULTS

Significant individual variations were observed in sinus penetration as a function of head position. In general, the maxillary sinus was the easiest to irrigate in most head positions (P < .05), followed by frontal and ethmoid, with sphenoid being the most difficult. Both the 90°-to-the-side and the 90°-forward positions were significantly more effective than the others (P < .05), with 90°-forward better for frontal sinuses and 90°-to-the-side superior for all other sinuses. The backfill was significantly superior to conventional technique in head positions involving a side tilt (P < .05).

CONCLUSION

Variations in technique and position significantly impacted irrigation outcome. Backfill irrigation that pushes fluid against gravity to pool around the ostium, seems to provide overall better outcomes. This study demonstrates the advantage of 3D printing as a rapid planning tool to guide irrigation strategies.

Intraoperative Predictor of Remission in Cushing Disease

BACKGROUND

Cushing disease represents a challenge for neurosurgeons, with high recurrence rates reported. Characteristics associated with remission are incompletely understood; thus, an intraoperative predictor for outcome would be valuable for assessing resection of adrenocorticotropic hormone (ACTH) secreting tissue.

OBJECTIVE

To evaluate whether intraoperative ACTH measurement could predict outcome after surgery for Cushing disease.

METHODS

Retrospective cohort study of 55 consecutive encounters with Cushing disease who had peripheral plasma ACTH levels measured intraoperatively before, during, and after tumor resection. The primary outcome measure was remission, defined by either 2 negative 24-hour urine free cortisol or 2 negative midnight salivary cortisol measurements. A logistic regression machine learning model was generated using recursive feature elimination.

RESULTS

Fifty-five operative encounters, comprising 49 unique patients, had a mean follow-up of 2.73 years (±2.11 years) and a median follow-up of 2.07 years. Remission was achieved in 69.1% (n = 38) of all operations and in 78.0% (n = 32) of those without cavernous sinus invasion. The final ACTH level measured intraoperatively correctly predicted outcome (area under the curve = 0.766; P value = .002). The odds ratio of remission in patients with the lowest quartile vs highest quartile final intraoperative ACTH was 23.4 ( P value = .002). Logistic regression machine learning model resulted in incorporating postoperative day 1 morning cortisol, final intraoperative ACTH that predicted outcome with an average area under the curve of 0.80 ( P = .0027).

CONCLUSION

Intraoperative ACTH may predict outcome after surgery in Cushing disease; furthermore, investigation is warranted.

Spontaneous rhinorrhea: a possible concealing initial symptom of ecchordosis physaliphora. Illustrative case

BACKGROUND

Spontaneous rhinorrhea may be the initial manifestation of ecchordosis physaliphora (EP). There are currently 47 published cases of symptomatic EP, with spontaneous rhinorrhea being one of the most prevalent symptoms. The authors report 1 case as a cause of cerebrospinal fluid (CSF) fistula.

OBSERVATIONS

A 46-year-old woman presented to the authors' clinic with meningitis secondary to nasal CSF leakage. The computed tomography (CT) scan indicated an imperceptibly thin/dehiscent focus along the posterior wall of the sphenoid air cell's midline. A tumor was identified during endoscopic endonasal CSF repair surgery. EP was diagnosed in the frozen and final pathology.

LESSONS

EP should be considered as a potential cause of spontaneous rhinorrhea. This initial clinical manifestation accounts for 35% of symptomatic EP cases. The prepontine and posterior sphenoid sinus wall appear to be the locations with the highest susceptibility. Surgical therapy of the fistula without excision of the lesion may result in insufficient issue resolution and recurrence.

Otolaryngologists' radiological assessment of nasal septum deviation symptomatology

OBJECTIVES

Nasal Septal Deviation (NSD) is one of the most common causes of nasal obstruction. This study aims to further examine the clinical utility of imaging assessment in the workup and management of symptomatic nasal septal deviation, across all levels of medical training.

STUDY DESIGN

Cross-sectional survey.

METHODS

CT scans of 10 confirmed NSD patients and 36 healthy controls (HC) were mixed and emailed through anonymous REDCap surveys to otolaryngologists in the US. The HC had no reported sinonasal obstruction symptoms-NOSE (NSD: 62.2 ± 12.5; HC: 5.69 ± 5.99, p < 0.05); SNOT-22 (NSD: 31.4 ± 14.5; HC: 9.72 ± 10.76, p < 0.05). The images consisted of a coronal slice at each subject's most deviated location. Participants were instructed to choose the patients suspected to present with symptoms of sinonasal obstruction.

RESULTS

88 otolaryngologists responded to the survey. 18 were excluded due to incomplete responses. On average, they identified 64.2 ± 29.8% of symptomatic NSD subjects correctly, but misidentified 54.6 ± 34.6% of HC as symptomatic. Their decisions were strongly correlated to degree of NSD (r = 0.69, p < 0.05). There exists a significant degree of NSD among HC (38.7 ± 17.2%), which does not significantly differ from symptomatic subjects (51.0 + 18.7%, p = 0.09). Residents and fellows performed similarly, with responses correlated between levels of training (r = 0.84-0.96, p < 0.05).

CONCLUSIONS

The incorporation of a substantial number of otolaryngologists, large patient sample, and blind mixing with HC gives us greater insight to the relative contribution of the extent of septal deviation to symptoms of nasal obstruction. Although NSD is a common factor contributing to nasal obstruction, the results of this study suggest that it is difficult to reliably infer obstructive symptoms based on degree of NSD on CT.

LEVEL OF EVIDENCE

Three.

Machine Learning-Based Analysis and Prediction of Unplanned 30-Day Readmissions After Pituitary Adenoma Resection: A Multi-Institutional Retrospective Study With External Validation

BACKGROUND

Unplanned readmission after transsphenoidal resection of pituitary adenoma can occur in up to 10% of patients but is unpredictable.

OBJECTIVE

To develop a reliable system for predicting unplanned readmission and create a validated method for stratifying patients by risk.

METHODS

Data sets were retrospectively collected from the National Surgical Quality Improvement Program and 2 tertiary academic medical centers. Eight machine learning classifiers were fit to the National Surgical Quality Improvement Program data, optimized using Bayesian parameter optimization and evaluated on the external data. Permutation analysis identified the relative importance of predictive variables, and a risk stratification system was built using the trained machine learning models.

RESULTS

Readmissions were accurately predicted by several classification models with an area under the receiving operator characteristic curve of 0.76 (95% CI 0.68-0.83) on the external data set. Permutation analysis identified the most important variables for predicting readmission as preoperative sodium level, returning to the operating room, and total operation time. High-risk and medium-risk patients, as identified by the proposed risk stratification system, were more likely to be readmitted than low-risk patients, with relative risks of 12.2 (95% CI 5.9-26.5) and 4.2 (95% CI 2.3-8.7), respectively. Overall risk stratification showed high discriminative capability with a C-statistic of 0.73.

CONCLUSION

In this multi-institutional study with outside validation, unplanned readmissions after pituitary adenoma resection were accurately predicted using machine learning techniques. The features identified in this study and the risk stratification system developed could guide clinical and surgical decision making, reduce healthcare costs, and improve the quality of patient care by better identifying high-risk patients for closer perioperative management.

Evidence of Nasal Cooling and Sensory Impairments Driving Patient Symptoms With Septal Deviation

OBJECTIVES/HYPOTHESIS

About 260,000 septoplasties are performed annually in the US to address nasal septal deviation (NSD). Yet, we do not consistently understand what aspects of NSD result in symptoms.

STUDY DESIGN

Blinded cohort study.

METHODS

Two fellowship-trained surgeons blindly reviewed computerized tomography (CTs) of 10 confirmed NSD patients mixed with 36 healthy controls. All patients were correctly identified, however, 24/36 controls were falsely identified by both surgeons as patients (33.3% specificity), which were grouped as asymptomatic NSD (aNSD), while the remaining controls as non-NSD (healthy). Acoustic rhinometry, rhinomanometry, individual CT-based computational fluid dynamics and nasal sensory testing were applied to address the puzzling questions of why these aNSD had no symptoms and, more fundamentally, what caused symptoms in sNSD patients.

RESULTS

aNSD reported no nasal symptoms - Nasal Obstruction Symptom Evaluation score (sNSD: 60.50 ± 13.00; aNSD: 5.20 ± 5.41; non-NSD: 6.66 ± 7.17, P < .05); 22-item Sino-Nasal Outcome Test score (sNSD: 32.60 ± 14.13; aNSD: 10.04 ± 10.10; non-NSD: 9.08 ± 12.42, P < .001). No significant differences in measured nasal resistance, minimum cross-sectional area (MCA), degree of septal deviation, and nasal airflow distributions were found between sNSD and aNSD groups. Only three variables differentiate sNSD versus aNSD: anterior averaged heat flux on deviated side, inferior turbinate peak heat flux on non-deviated side, and nasal cool sensitivity measured by menthol lateralization threshold, with no significant differences among these variables found between the two healthy groups (aNSD vs. non-NSD). These variables by themselves or combined can differentiate sNSD from controls with higher specificity than the physicians (ROC area under the curve = 0.84 with 70% sensitivity and 91.6% specificity).

CONCLUSIONS

This study sheds light on the potential mechanisms of NSD symptomatology: distorted nasal cooling due to NSD exacerbated by poorer nasal mucosal sensitivity. It further supports our previous hypothesis that nasal obstruction complaints do not result directly from obstruction, rather from the capacity of our nose to subjectively sense airflow cooling.

LEVEL OF EVIDENCE

3 Laryngoscope, 132:509-517, 2022.

Use of computational fluid dynamics (CFD) to model observed nasal nitric oxide levels in human subjects

BACKGROUND

Upper airway nitric oxide (NO) is physiologically important in airway regulation and defense, and nasal NO (nNO) levels typically exceed those in exhaled breath (fractional exhaled NO [FeNO]). Elevated concentrations of NO sampled from the nose, in turn, reflect even higher concentrations in the paranasal sinuses, suggesting a "reservoir" role for the latter. However, the dynamics of NO flux within the sinonasal compartment are poorly understood.

METHODS

Data from 10 human subjects who had previously undergone both real-time nNO sampling and computed tomography (CT) scanning of the sinuses were analyzed using computational fluid dynamics (CFD) methods. Modeled and observed nNO values during the initial 2-s transient ("spike") during nasal exhalation were then compared.

RESULTS

Examining the initial 2-s transient spike for each subject (as well as the pooled group), there was a statistically significant correlation between modeled and observed nNO levels, with r values ranging from 0.43 to 0.89 (p values ranging from <0.05 to <0.0001). Model performance varied between subjects, with weaker correlations evident in those with high background (FeNO) levels. In addition, the CFD simulation suggests that ethmoid sinuses (>60%) and diffusion process (>54%) contributed most to total nasal NO emissions.

CONCLUSION

Analysis of this dataset confirms that CFD is a valuable modeling tool for nNO dynamics, and highlights the importance of the ethmoid sinuses, as well as the role of diffusion as an initiating step in sinonasal NO flux. Future model iterations may apply more generally if baseline FeNO is taken into account.

Complications after 1002 endoscopic endonasal approach procedures at a single center: lessons learned, 2010-2018

OBJECTIVE

The endoscopic endonasal approach (EEA) has evolved into a mainstay of skull base surgery over the last two decades, but publications examining the intraoperative and perioperative complications of this technique remain scarce. A prior landmark series of 800 patients reported complications during the first era of EEA (1998-2007), parallel to the development of many now-routine techniques and technologies. The authors examined a single-institution series of more than 1000 consecutive EEA neurosurgical procedures performed since 2010, to elucidate the safety and risk factors associated with surgical and postoperative complications in this modern era.

METHODS

After obtaining institutional review board approval, the authors retrospectively reviewed intraoperative and postoperative complications and their outcomes in patients who underwent EEA between July 2010 and June 2018 at a single institution.

RESULTS

The authors identified 1002 EEA operations that met the inclusion criteria. Pituitary adenoma was the most common pathology (n = 392 [39%]), followed by meningioma (n = 109 [11%]). No patients died intraoperatively. Two (0.2%) patients had an intraoperative carotid artery injury: 1 had no neurological sequelae, and 1 had permanent hemiplegia. Sixty-one (6.1%) cases of postoperative cerebrospinal fluid leak occurred, of which 45 occurred during the original surgical hospitalization. Transient postoperative sodium dysregulation was noted after 87 (8.7%) operations. Six (0.6%) patients were treated for meningitis, and 1 (0.1%) patient died of a fungal skull base infection. Three (0.3%) patients died of medical complications, thereby yielding a perioperative 90-day mortality rate of 0.4% (4 deaths). High-grade (Clavien-Dindo grade III-V) complications were identified after 103 (10%) EEA procedures, and multivariate analysis was performed to determine the associations between factors and these more serious complications. Extradural EEA was significantly associated with decreased rates of these high-grade complications (OR [95% CI] 0.323 [0.153-0.698], p = 0.0039), whereas meningioma pathology (OR [95% CI] 2.39 [1.30-4.40], p = 0.0053), expanded-approach intradural surgery (OR [95% CI] 2.54 [1.46-4.42], p = 0.0009), and chordoma pathology (OR [95% CI] 9.31 [3.87-22.4], p < 0.0001) were independently associated with significantly increased rates of high-grade complications.

CONCLUSIONS

The authors have reported a large 1002-operation cohort of EEA procedures and associated complications. Modern EEA surgery for skull base pathologies has an acceptable safety profile with low morbidity and mortality rates. Nevertheless, significant intraoperative and postoperative complications were correlated with complex intradural procedures and meningioma and chordoma pathologies.

Endoscopic Endonasal Transtubercular Approach for Resection of Giant Pituitary Adenomas With Subarachnoid Extension: The "Second Floor" Strategy to Avoid Postoperative Apoplexy

BACKGROUND

Giant pituitary adenomas (GPAs) with subarachnoid extension can be challenging to achieve a gross total resection through a single endonasal or transcranial approach, and any residual tumor is at risk for postoperative apoplexy. Intraoperative venous congestion of the suprasellar tumor can occur following resection of the sellar tumor, limiting tumor descent, and leading to suprasellar residual. We propose a technique for resecting the suprasellar component first, which we call the "second floor" strategy (SFS) for GPA.

METHODS

A retrospective review of cases from 2010-2020 identified 586 endoscopic endonasal approaches (EEAs) for pituitary adenoma resection. We report the rate of postoperative apoplexy and describe the SFS technique used in 2 cases.

RESULTS

Of 586 cases, 2 developed symptomatic postoperative apoplexy (0.3%), and a third transferred to our care after undergoing postoperative apoplexy. All 3 cases had subarachnoid extension of a pituitary adenoma, underwent EEA, and had residual suprasellar tumor. All 3 had permanent morbidity due to the postoperative apoplexy including blindness, stroke, or death, despite undergoing reoperation. The SFS was used for reoperation on 1 of these patients and as a primary strategy in a fourth patient who presented with a GPA with subarachnoid extension. We describe the SFS technique and demonstrate it with a 2-dimensional operative video.

CONCLUSIONS

Postoperative apoplexy of residual adenoma is a rare but serious complication after GPA resection. The proposed SFS allows early access to the suprasellar tumor and may improve the ability to safely achieve a gross total resection without need for additional procedures.

Collagen Matrix With Mucoperiosteum Graft as an Effective Fatless Flapless Reconstruction After Endoscopic Pituitary Adenoma Resection

BACKGROUND

Proper skull base reconstruction after endoscopic endonasal pituitary surgery is of great importance to decrease the rate of complications.

OBJECTIVE

To assess the safety and efficacy of reconstruction with materials other than fat graft and naso-septal flaps (NSF) to avoid their associated morbidities.

METHODS

The authors' institutional database for patients who underwent endoscopic endonasal approach for pituitary adenoma was reviewed. Exclusion criteria included recurrence, postradiation therapy, and reconstruction by fat graft or NSF. They were divided into group A, where collagen matrix (CM) (DuraGen® Plus Matrix, Integra LifeSciences Corporation, Plainsboro, New Jersey) alone was used; group B, where CM and simple mucoperiosteum graft were used and group C, which included cases without CM utilization.

RESULTS

The study included 252 patients. No age, gender, or body mass index statistically significant difference between groups. Group B included the largest tumor size (23.0 mm) in comparison to groups A (18.0 mm) and C (13.0 mm). Suprasellar extension was more frequently present (49.4%) in comparison to groups A (29.8%, P = .001) and C (21.2%, P < .001). Postoperative cerebrospinal fluid (CSF) leak rate was 0%, 2.9%, and 6% in groups A, B, and C, respectively. In group B, the CSF leak rate decreased from 45.9% intraoperatively to 2.9% postoperatively (P < .001). In group A, the CSF leak reduction rate was almost statistically significant (P = .06).

CONCLUSION

Utilization of CM and simple mucosperiosteal graft in skull base reconstruction following pituitary adenoma surgery is an effective method to avoid the morbidities associated with NSF or fat graft.

The role of indocyanine green fluorescence in endoscopic endonasal skull base surgery and its imaging correlations

OBJECTIVE

The use of endoscope-integrated indocyanine green (E-ICG) has recently been introduced in skull base surgery. The quantitative correlation between E-ICG and T1-weighted gadolinium-enhanced (T1WGd) images for skull base tumors has not been previously assessed, to the authors' knowledge. In this study, the authors investigated the indications for use and the limitations of E-ICG and sought to correlate the endoscopic fluorescence pattern with MRI contrast enhancement.

METHODS

Following IRB approval, 20 patients undergoing endoscopic endonasal skull base surgery between June 2017 and August 2018 were enrolled in the study. Tumor fluorescence was measured using a blue color value and blood fluorescence as a control. Signal intensities (SIs) of tumor T1WGd images were measured and the internal carotid artery (ICA) SI was used as a control. For pituitary adenoma, the pituitary gland fluorescence was also measured. The relationships between ICG fluorescence and MRI enhancement measurements were analyzed.

RESULTS

Data showed that in pituitary adenoma there was a strong correlation between the ratios of gland/blood fluorescence to gland/ICA SI (n = 8; r = 0.92; p = 0.001) and tumor/blood fluorescence to tumor/ICA SI (n = 9; r = 0.82; p = 0.006). In other pathologies there was a strong correlation between the ratios of tumor/blood fluorescence and tumor/ICA SI (n = 9; r = 0.74; p = 0.022). The ICG fluorescence allowed perfusion assessment of the pituitary gland as well as of the nasoseptal flaps. Visualization of the surrounding vasculature was also feasible.

CONCLUSIONS

Defining the indications and understanding the limitations are critical for the effective use of E-ICG. Tumor fluorescence seems to correlate with preoperative MRI contrast enhancement.

Regional Peak Mucosal Cooling Predicts Radiofrequency Treatment Outcomes of Nasal Valve Obstruction

OBJECTIVES/HYPOTHESIS

Low energy radiofrequency may offer effective treatment for narrow or obstructed nasal valve, yet its precise mechanism is not fully understood.

STUDY DESIGN

Prospective, nonrandomized, case series.

METHODS

Twenty prospective patients with internal nasal valve obstruction underwent office-based Vivaer treatment (Aerin Medical, Inc) under local anesthesia. Computational fluid dynamics (CFD) models were constructed based on the pre- and 90 days post-procedure computed tomography (CT) scans to identify salient changes in nasal airflow parameters.

RESULTS

Patients' Nasal Obstruction Symptom Evaluation score (NOSE: pre-treatment 78.89 ± 11.57; post-treatment 31.39 ± 18.30, P = 5e-7) and Visual Analog Scale of nasal obstruction (VAS: pre-treatment 6.01 ± 1.83; post-treatment 3.44 ± 2.11, P = 1e-4) improved significantly at 90 days after the minimally invasive approach. Nasal airway volume in the treatment area increased ~7% 90 days post-treatment (pre-treatment 5.97 ± 1.20, post-treatment 6.38 ± 1.50 cm³ , P = .018), yet there were no statistically significant changes in the measured peak nasal inspiratory flowrate (PNIF, pre-treatment: 60.16 ± 34.49; post-treatment: 72.38 ± 43.66 ml/s; P = .13) and CFD computed nasal resistance (pre-treatment: 0.096 ± 0.065; post-treatment: 0.075 ± 0.026 Pa/(ml/s); P = .063). As validation, PNIF correlated significantly with nasal resistance (r = 0.47, P = .004). Among all the variables, only the peak mucosal cooling posterior to the nasal vestibule significantly correlated with the NOSE at baseline (r = -0.531, P = .023) and with post-treatment improvement (r = 0.659, P = .003).

CONCLUSION

Minimal remodeling of the nasal valve (7% in this study) may have a profound effect on perceived nasal obstruction, despite little effect on nasal resistance, or PNIF. The results corroborated our previous findings that subjective relief of nasal obstruction correlates with regional mucosal cooling rather than nasal resistance or peak flow rate, a potential target for future effective, personalized therapeutic approaches.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E1760-E1769, 2021.

The Eustachian Tube as a Landmark for Early Identification of the Abducens Nerve During Endonasal Transclival Approaches

BACKGROUND

Expanded endonasal approaches have the potential to injure the abducens nerve (cranial nerve [CN] VI). The nerve's root entry zone (REZ) and cisternal segment (CS) are particularly prone to injury during the clivus resection and dural incision of transclival approaches.

OBJECTIVE

To investigate the role of the eustachian tube (ET) as a surgical landmark for the REZ and CS of CN VI.

METHODS

Transclival expanded endonasal approaches were performed bilaterally in 6 fresh-frozen cadaveric specimens (12 sides). Anatomic relationships between ET and CN VI were documented with neuronavigation.

RESULTS

The mean vertical distance from the inferior brainstem point to the horizontal projection of CN VI REZ, CS midpoint, and interdural segment (ID) were 26.38 mm (95% confidence interval [CI] 17.36-35.4), 38.61 mm (95% CI 25.61-51.61), and 42.68 mm (95% CI 30.14-55.22), respectively. The relative vertical distance from the ET to the horizontal projections of the REZ, CS midpoint, and its ID were 6.43 mm (95% CI 3.25-9.61), 18.66 mm (95% CI 11.52-25.8), and 22.72 mm (95% CI 16.02-29.42), respectively. In the axial plane the angles between the ET and (1) the REZ and its midline horizontal projection point, (2) the midpoint and its midline horizontal projection point, and (3) ID and its midline horizontal projection point were 9.81 ± SD 5.20°, 18.50 ± SD 4.87°, and 24.71 ± SD 6.21°, respectively.

CONCLUSION

The ET may serve as a constant landmark to reliably predict the position of the REZ and CS of CN VI.

Anatomic Nuances of the Ophthalmic Artery Origin from a Ventral Viewpoint: Considerations and Implications for Endoscopic Endonasal Surgery

BACKGROUND

The origin of the ophthalmic artery is within the surgical field of endoscopic endonasal approaches (EEAs) to the suprasellar and parasellar regions. However, its anatomy from the endoscopic point-of-view has not been adequately elucidated.

OBJECTIVE

To highlight the anatomy of the ophthalmic artery origin from an endoscopic endonasal perspective.

METHODS

The origin of the ophthalmic artery was studied bilaterally under endoscopic visualization, after performing transplanum/transtubercular EEAs in 17 cadaveric specimens (34 arteries). Anatomic relationships relevant to surgery were evaluated. To complement the cadaveric findings, the ophthalmic artery origin was reviewed in 200 "normal" angiographic studies.

RESULTS

On the right side, 70.6% of ophthalmic arteries emerged from the superior aspect, while 17.6% and 11.8% emerged from the superomedial and superolateral aspects of the intradural internal carotid artery, respectively. On the left, 76.5%, 17.6%, and 5.9% of ophthalmic arteries emerged from the superior, superomedial, and superolateral aspects of the internal carotid, respectively. Similar findings were observed on angiography. All ophthalmic arteries emerged at the level of the medial opticocarotid recess. Overall, 47%, 26.5%, and 26.5% of ophthalmic arteries (right and left) were inferolateral, inferior, and inferomedial to the intracranial optic nerve segment, respectively. On both sides, the intracranial length of the ophthalmic artery ranged from 1.5 to 4.5 mm (mean: 2.90 ± standard deviation of 0.74 mm).

CONCLUSION

Awareness of the endoscopic nuances of the ophthalmic artery origin is paramount to minimize the risk of sight-threatening neurovascular injury during EEAs to the suprasellar and parasellar regions.

Sellar Cholesterol Granuloma Mimicking Cystic Sellar Lesions: A Report of Three Cases and Literature Review

BACKGROUND

Cystic lesions in the sellar region include a variety of entities, such as craniopharyngioma, Rathke cleft cyst (RCC), intrasellar arachnoid cyst, cystic pituitary adenomas, cholesterol granulomas (CGs), and xanthogranulomas (XGs). The distinction among them remains a preoperative challenge due to similarities in their clinical and radiologic findings.

CASE DESCRIPTION

We describe 3 cases with cystic sellar lesions. The first patient is a woman who presented with headache and hormonal disturbances, including high levels of prolactin, with a sellar and suprasellar cystic lesion discovered on magnetic resonance imaging. She was initially treated with dopamine agonists with normalization of prolactin levels but no changes on the size of the lesion. She underwent an endoscopic endonasal resection and the histology resulted in a CG/XG. The second patient is a woman who consulted for an incidentally discovered sellar cyst. During the follow-up, the lesion demonstrated enlargement with compression of the optic chiasm. With a preoperative diagnosis of RCC, the lesion was removed through an endoscopic endonasal transsellar approach. Final pathologic diagnosis was consistent with CG/XG. The third case was that of a man who presented with refractory headaches and vision loss, with a sellar/suprasellar cystic lesion on magnetic resonance imaging. He underwent endoscopic endonasal transsellar surgery for resection of what preoperatively was thought to be a giant RCC; final pathology again was consistent with CG/XG.

CONCLUSIONS

CG/XG is an uncommon pathology with unspecific clinical and radiologic features. However, this pathology should be considered in the differential diagnosis of mixed cystic/solid lesions in the sellar region.

Improving Function in Cavernous Sinus Meningiomas: A Modern Treatment Algorithm

Background: The efficacy and safety of radiosurgery led to paradigm shift in the management of cavernous sinus meningiomas. Nevertheless, patients are still significantly affected by cranial nerve deficits related to the mass effect of these tumors. Our management strategy involves the combination of a functional surgical decompression followed by radiation therapy. Methods: We reviewed a single institution's cohort of patients who underwent endoscopic endonasal decompression (EED) for symptomatic meningiomas primarily involving the cavernous sinus (CS) from 2010 to 2016. The preoperative neuro-ophthalmological exam was compared to the 1- and 6-month postoperative exams. The patient's length of hospital stay, complications, and radiological and clinical follow-up were noted. Results: A total of 17 patients underwent EED for CS meningiomas that fit our radiological criteria. The final outcome at the 6-month visit showed five patients (62.5%) with normalization of deficit and three patients (37.5%) with partial improvement of the CNII deficit. Out of the 12 patients who had cavernous sinus cranial nerves (CSCN) deficits, the final outcome at the 6-month visit showed four patients (33.33%) with normalization of deficit, seven patients (58.3%) with partial improvement, and one patient (8.33%) with no improvement. There were no intraoperative complications. Conclusion: The EED for CS meningiomas is a valuable technique when addressing acute/subacute CNII and CSCN deficits. This conservative surgical approach showed good functional outcomes, low morbidity, and low complication rates. However, it does not exempt the need for radiosurgery/radiation therapy for control of tumor growth.

The Angelina Dissectors: A Novel Design of Dissectors for Endoscopic Endonasal Approaches

Background  The description and refinement of the transsphenoidal approach would not be possible without new tools and technologies developed by surgeons to facilitate this approach, which is nowadays the standard procedure for more than 90% of sellar lesions. The latest major change in transsphenoidal surgery was the introduction of the rigid endoscope and the subsequent description of the endoscopic endonasal approach. Traditional bayoneted instruments, when used for this technique, were inadequate. New instruments designed, specifically for this technique, are necessary to facilitate the surgeon's work and improve patient outcome. Objective  This study describes a novel design of dissectors created specifically for endoscopic endonasal approaches. Methods  To develop and design the Angelina dissectors, we used our extensive surgical experience to identify the shortcomings of the available dissectors used for transsphenoidal surgery and created the Angelina dissectors. Results  The Angelina dissector was designed with a unique shaft shape which facilitates endoscopic endonasal surgery. Conclusion  Even though an endoscopic endonasal approach is possible using other instruments, the design of these dissectors aids the surgeon's work. It is our impression, based on personal experience that it allows more freedom of movement and dexterity during the procedure, which could translate as an improved patient outcome.

Surgical outcomes of the endonasal endoscopic approach within a standardized management protocol for repair of spontaneous cerebrospinal fluid rhinorrhea

OBJECTIVE

Spontaneous CSF leaks are rare, their diagnosis is often delayed, and they can precipitate meningitis. Craniotomy is the historical "gold standard" repair for these leaks. An endonasal endoscopic approach (EEA) offers potentially less invasiveness and lower surgical morbidity than a traditional craniotomy but must yield the same surgical success. A paucity of data exists studying EEA as the primary management for spontaneous CSF leaks.

METHODS

The authors retrospectively reviewed patients undergoing spontaneous CSF rhinorrhea repair at their institution from July 2010 to August 2018. Standardized management includes EEA as first-line treatment, and lumbar puncture (LP) performed 24-48 hours postoperatively. If opening pressure on LP is elevated, CSF diversion or acetazolamide therapy is used as needed. Perioperative lumbar drains are not used.

RESULTS

Of 46 patients identified, the most common CSF rhinorrhea etiology was encephalocele (28/46, 60.9%), and the most common location was cribriform/ethmoid (26/46, 56.5%). Forty-three patients underwent EEA alone, and 3 underwent a simultaneous EEA/craniotomy. The most common repair strategy was nasoseptal or other pedicled flaps (18/46, 39.1%). Postoperatively, 15 patients (32.6%) received CSF diversion due to elevated ICP, with BMI > 40 kg/m2 being a significant risk factor (odds ratio 4.35, p = 0.033) for postrepair shunt placement. Twelve patients received acetazolamide therapy for treatment of mildly elevated pressures. The average opening pressure of the shunted group was 36 cm H2O and the average for the acetazolamide-only group was 26 cm H2O. Two patients underwent CSF leak repair revision, one because of progressive fungal sinusitis and the other because of recurrent CSF leak. The mean follow-up duration was 15 months.

CONCLUSIONS

The paradigm of EEA repair of spontaneous CSF rhinorrhea with postoperative LP to identify undiagnosed idiopathic intracranial hypertension appears to be safe and effective. In the authors' cohort, morbid obesity was statistically associated with the need for postoperative CSF diversion. This has implications for future surgical treatment as obesity levels continue to rise worldwide.

Quantitative analysis of the surgical exposure and surgical freedom between transcranial and transorbital endoscopic anterior petrosectomies to the posterior fossa

OBJECT

This study proposes a variation of the transorbital endoscopic approach (TOEA) that uses the lateral orbit as the primary surgical corridor, in a minimally invasive fashion, for the posterior fossa (PF) access. The versatility of this technique was quantitatively analyzed in comparison with the anterior transpetrosal approach (ATPA), which is commonly used for managing lesions in the PF.

METHODS

Anatomical dissections were carried out in 5 latex-injected human cadaveric heads (10 sides). During dissection, the PF was first accessed by TOEAs through the anterior petrosectomy, both with and without lateral orbital rim osteotomies (herein referred as the lateral transorbital approach [LTOA] and the lateral orbital wall approach [LOWA], respectively). ATPAs were performed following the orbital approaches. The stereotactic measurements of the area of exposure, surgical freedom, and angles of attack to 5 anatomical targets were obtained for statistical comparison by the neuronavigator.

RESULTS

The LTOA provided the smallest area of exposure (1.51 ± 0.5 cm2, p = 0.07), while areas of exposure were similar between LOWA and ATPA (1.99 ± 0.7 cm2 and 2.01 ± 1.0 cm2, respectively; p = 0.99). ATPA had the largest surgical freedom, whereas that of LTOA was the most restricted. Similarly, for all targets, the vertical and horizontal angles of attack achieved with ATPA were significantly broader than those achieved with LTOA. However, in LOWA, the removal of the lateral orbital rim allowed a broader range of movement in the horizontal plane, thus granting a similar horizontal angle for 3 of the 5 targets in comparison with ATPA.

CONCLUSIONS

The TOEAs using the lateral orbital corridor for PF access are feasible techniques that may provide a comparable surgical exposure to the ATPA. Furthermore, the removal of the orbital rim showed an additional benefit in an enhancement of the surgical maneuverability in the PF.

Remote Leptomeningeal Dissemination in Olfactory Neuroblastoma Mimicking Multiple Parasagittal Meningiomas: Diagnostic and Therapeutic Challenge

BACKGROUND

Olfactory neuroblastoma (ON) is a highly aggressive and locally recurrent neoplasm. Distant systemic metastases are not uncommon, but remote leptomeningeal dissemination is extremely rare.

CASE DESCRIPTION

We report 2 cases of ON previously treated with endoscopic endonasal radical surgical resection and radiotherapy. After a relatively long period of disease-free survival, multiple leptomeningeal lesions were seen around the sagittal sinus giving a radiologic appearance of parasagittal meningiomas. Both patients underwent surgery and multimodal treatment with radiotherapy and chemotherapy for the disseminated disease. Pathologic examination confirmed the parasagittal lesions as metastatic ON.

CONCLUSIONS

A high suspicion of secondary disease should be maintained in patients with previous history of ON and parasagittal leptomeningeal enhancing lesion, particularly when multiple lesions are detected around the sagittal sinus. Radical resection and multimodal treatment are warranted to improve long-term outcome. Understanding the venous drainage route as a potential pathway for remote seeding from the primary site of disease has therapeutic implications. We postulate that en-bloc tumor resection and proximal sagittal sinus ligation might reduce potential for leptomeningeal metastasis.

Peak Sinus Pressures During Sneezing in Healthy Controls and Post-Skull Base Surgery Patients

OBJECTIVES/HYPOTHESIS

Patients are frequently advised to sneeze with an open mouth and avoid nose-blowing following an endoscopic endonasal approache (EEA) to the skull base, despite a lack of quantitative evidence. This study applies computational fluid dynamics (CFD) to quantify sinus pressures along the skull base during sneezing.

STUDY DESIGN

Case-control series.

METHODS

Computed tomography or magnetic resonance imaging scans of four post-EEA patients and four healthy controls were collected and analyzed utilizing CFD techniques. A pressure drop of 6,000 Pa was applied to the nasopharynx based on values in the literature to simulate expiratory nasal airflow during sneezing. Peak pressures along the skull base in frontal, ethmoid, and sphenoid sinuses were collected.

RESULTS

Significant increases in skull base peak pressure was observed during sneezing, with significant individual variations from 2,185 to 5,685 Pa. Interestingly, healthy controls had significantly higher pressures compared to post-EEA patients (5179.37 ± 198.42 Pa vs. patients 3,347.82 ± 1,472.20 Pa, P < .05), which could be related to higher anterior nasal resistance in unoperated healthy controls (0.44 ± 0.22 vs. 0.31 ± 0.16 Pa/mL/sec for patients, P = .38). The sinus pressure buildup may be due to airway resistance functioning as a valve preventing air from being released quickly. Supporting this theory, there was a strong correlation (r = 0.82) between peak skull base pressure and the ratio of anterior resistance to total resistance. Within-subject variation in pressures between different skull base regions was much lower (average = ~5%).

CONCLUSIONS

This study provided the first quantitative analysis of air pressure along the skull base during sneezing in post-EEA patients through CFD, suggesting that pressure buildup may depend on individual anatomy.

LEVEL OF EVIDENCE

3b Laryngoscope, 130:2138-2143, 2020.

Extended Endoscopic Endonasal Clipping of Intracranial Aneurysms: An Anatomic Feasibility Study

BACKGROUND

Intracranial aneurysms (IAs) located in the midline region represent formidable challenge owing to their deep location. The objective of this study was to assess feasibility and identify the limitations of endoscopic endonasal clipping of IAs. We further aimed to describe the locations and characteristics of aneurysms that may be amenable for endoscopic endonasal clipping; thus outlining the indications of these approaches.

METHODS

Fifteen latex-injected cadaveric heads were used for endoscopic endonasal exposure of anterior and posterior cerebral circulations. An aneurysm simulator model with 2 different sizes was used at the common sites for IAs to emulate a real surgery. Key measured parameters included "exposure of vessels and their respective perforators," "ability to gain proximal/distal control," and "possibility of clip placement" according to the size, direction, and location of the aneurysm model. Maneuverability of instruments and the need for pituitary gland transposition were assessed and recorded as well.

RESULTS

Exposure of the anterior communicating artery complex and the common sites of posterior circulation aneurysms were feasible. The size, location, and direction of the aneurysm model had an impact on obtaining proximal and/or distal control, and the ability of clip placement.

CONCLUSIONS

Clipping of midline aneurysms of the posterior circulation is feasible via endoscopic endonasal approach. Small-sized ventrally and medially directed aneurysm models carried a better probability of getting proximal and/or distal control, as well as better overall ability to place a clip. The endonasal route seems to provide a limited condition for proper management of anterior circulation aneurysms.

Asymptomatic vs symptomatic septal perforations: a computational fluid dynamics examination

BACKGROUND

A nasal septal perforation (NSP) can lead to frustrating symptoms for some patients while remaining completely asymptomatic for others, without a clear mechanism differentiating them.

METHODS

We applied individual computed tomography (CT)-based computational fluid dynamics (CFD) to examine the nasal aerodynamics differences between 5 asymptomatic and 15 symptomatic NSP patients. Patients' symptoms were confirmed through interviews, 22-item Sino-Nasal Outcome Test score (asymptomatic, 25 ± 18.8; symptomatic, 53.7 ± 18.2), nasal obstruction symptom evaluation score (asymptomatic, 28.0 ± 32.1; symptomatic, 62.2 ± 32.2), and review of medical history.

RESULTS

No statistical differences were found in perforation location, size (asymptomatic, 1.94 ± 1.88 cm² ; symptomatic, 1.36 ± 1.44 cm² ), nasal resistance (asymptomatic, 0.059 ± 0.012 Pa·s/mL; symptomatic, 0.063 ± 0.022 Pa·s/mL), and computed flow rate shunting across the perforation (asymptomatic, 52.9 ± 30.9 mL/s; symptomatic, 27.4 ± 23.6 mL/s; p > 0.05). However, symptomatic patients had significantly higher wall shear stress (WSS) and heat flux, especially along the posterior perforation margin (WSS, 0.54 ± 0.12 vs 1.15 ± 0.49 Pa, p < 0.001; heat flux, 0.21 ± 0.05 vs 0.37 ± 0.14 W/cm² , p < 0.01). A WSS cutoff at 0.72 Pa can separate asymptomatic vs symptomatic NSP with 87% sensitivity and 100% specificity. Flow visualization showed flow peaks toward the posterior margin that may be responsible for the high WSS and heat flux among symptomatic NSPs.

CONCLUSION

This study is the first CFD examination of asymptomatic and symptomatic NSP with regional aerodynamics and stress abnormalities, beyond size or location, being implicated as the mechanism behind the symptomology of NSP. This finding could serve as an objective basis for future personalized treatment decisions and optimization.

Computational fluid dynamic analysis of aggressive turbinate reductions: is it a culprit of empty nose syndrome?

BACKGROUND

Empty nose syndrome (ENS) remains highly controversial, with aggressive inferior turbinate reduction (ITR) or mucociliary dysfunction frequently implicated. However, the appropriate degree of ITR is highly debatable.

METHODS

We applied individual computed tomography (CT)-based computational fluid dynamics (CFD) to 5 patients receiving relatively aggressive ITR but with no ENS symptoms, and compared them to 27 symptomatic ENS patients who all had histories of aggressive ITRs, and 42 healthy controls. Patients' surgical outcomes were confirmed with 22-item Sino-Nasal Outcome Test (SNOT-22) (ITR: 6.40 ± 4.56; ENS: 58.2 ± 15.9; healthy: 13.2 ± 14.9), Nasal Obstruction Symptom Evaluation (NOSE) scores (ITR: 4.00 ± 2.24; ENS: 69.4 ± 17.1; healthy: 11.9 ± 12.9), and Empty Nose Syndrome 6-Item Questionnaire (ENS6Q) (≥11 for ENS).

RESULTS

Both aggressive ITR without ENS symptoms and symptomatic ENS patients had significantly lower nasal resistance (ITR: 0.059 ± 0.020 Pa·s/mL; ENS: 0.052 ± 0.015 Pa·s/mL; healthy: 0.070 ± 0.021 Pa·s/mL) and higher cross-sectional areas surrounding the inferior turbinate (ITR: 0.94 ± 0.21 cm² ; ENS: 1.19 ± 1.05 cm² ; healthy: 0.42 ± 0.22 cm² ) than healthy controls. The lack of significant differences among patient groups indicated similar degrees of surgeries between ITR with and without ENS symptom cohorts. However, symptomatic ENS patients have paradoxical significantly less airflow in the inferior meatus (ITR: 47.7% ± 23.6%; ENS: 25.8% ± 17.6%; healthy: 36.5 ± 15.9%; both p < 0.01), but higher airflow around the middle meatus (ITR: 49.7% ± 22.6%; ENS: 66.5% ± 18.3%; healthy: 49.9% ± 15.1%, p < 0.0001) than aggressive ITR without symptoms and controls. Aggressive ITR patients have increased inferior meatus airflow as expected (p < 0.05). This imbalanced airflow produced less inferior wall-shear-stress distribution among symptomatic ENS patients only (ITR: 42.45% ± 11.4%; ENS: 32.2% ± 12.6%; healthy: 49.7% ± 9.9%). ENS patients (n = 12) also had impaired nasal trigeminal function, as measured by menthol lateralization detection thresholds (ITR: 15.2 ± 1.2; ENS: 10.3 ± 3.9; healthy: 13.8 ± 3.09, both p < 0.0001). Surprisingly, aggressive ITR patients without ENS symptoms have better menthol lateralization detection thresholds (LDTs) than healthy controls.

CONCLUSION

Although turbinate tissue loss is linked with ENS, the degree of ITR that might distinguish postoperative patient satisfaction in their nasal breathing vs development of ENS symptoms is unclear. Our results suggest that a combination of distorted nasal aerodynamics and loss of mucosal sensory function may potentially lead to ENS symptomology.

Erratum: Endoscopic Endonasal Transplanum-Transtuberculum Sellae Approach for the Resection of a Diaphragma Sellae Meningioma

[This corrects the article DOI: 10.1055/s-0038-1624587.].

Nasal Structural and Aerodynamic Features That May Benefit Normal Olfactory Sensitivity

Nasal airflow that effectively transports ambient odors to the olfactory receptors is important for human olfaction. Yet, the impact of nasal anatomical variations on airflow pattern and olfactory function is not fully understood. In this study, 22 healthy volunteers were recruited and underwent computed tomographic scans for computational simulations of nasal airflow patterns. Unilateral odor detection thresholds (ODT) to l-carvone, phenylethyl alcohol (PEA) and d-limonene were also obtained for all participants. Significant normative variations in both nasal anatomy and aerodynamics were found. The most prominent was the formation of an anterior dorsal airflow vortex in some but not all subjects, with the vortex size being significantly correlated with ODT of l-carvone (r = 0.31, P < 0.05). The formation of the vortex is likely the result of anterior nasal morphology, with the vortex size varying significantly with the nasal index (ratio of the width and height of external nose, r = -0.59, P < 0.001) and nasal vestibule "notch" index (r = 0.76, P < 0.001). The "notch" is a narrowing of the upper nasal vestibule cartilage region. The degree of the notch also significantly correlates with ODT for PEA (r = 0.32, P < 0.05) and l-carvone (r = 0.33, P < 0.05). ODT of d-limonene, a low mucosal soluble odor, does not correlate with any of the anatomical or aerodynamic variables. The current study revealed that nasal anatomy and aerodynamics might have a significant impact on normal olfactory sensitivity, with greater airflow vortex and a narrower vestibule region likely intensifying the airflow vortex toward the olfactory region and resulting in greater olfactory sensitivity to high mucosal soluble odors.

Erratum: Endoscopic Endonasal Transtuberculum Sellae Approach for the Resection of Suprasellar Epidermoid Cyst

[This corrects the article DOI: 10.1055/s-0038-1624590.].

The Role of Endonasal Endoscopic Optic Nerve Decompression as the Initial Management of Primary Optic Nerve Sheath Meningiomas

Background  The management of optic nerve sheath meningiomas (ONSMs) remains controversial. Surgical decompression through traditional resective techniques has been associated with significant morbidity. While radiation therapy, the current modality of choice is not exempt of risks. Transnasal endoscopic optic nerve decompression (EOND) offers a direct route to the orbit, optic canal, and orbital apex, providing a minimally invasive alternative. Objective  The main objective of this article is to assess EOND as the initial management of symptomatic patients with primary ONSM. Methods  Patients with ONSMs without a history of radiotherapy who underwent EOND were retrospectively reviewed. Postoperative imaging, duration of follow-up, and visual outcomes at the last ophthalmology visit were assessed. Results  Four women (age range 25-63 years) with primary ONSMs that underwent EOND were identified. All patients displayed subjective and objective baseline signs of vision loss. Additionally, baseline proptosis, diplopia, optic nerve atrophy, and ocular pain were identified. In none of the cases, the optic nerve sheath was breached. Following EOND, all patients deferred treatment with adjuvant radiotherapy. At a mean postoperative follow-up of 14 months, all patients were clinically stable without evidence of disease progression on imaging or physical examination. At last ophthalmologic evaluation, three out of four showed objective improvements from baseline visual acuity and visual field (remaining patient had baseline optic nerve atrophy). Conclusion  These results suggest that EOND could be a viable initial treatment modality of selected primary ONSM cases. Further studies are warranted to determine long-term efficacy and its role in a stepwise progression of management, preceding radiotherapy.

Comparative Analysis of the Exposure and Surgical Freedom of the Endoscopic Extended Minipterional Craniotomy and the Transorbital Endoscopic Approach to the Anterior and Middle Cranial Fossae

BACKGROUND

Numerous minimally invasive approaches to the skull base have been successively developed. Knowledge of the surgical nuances of a specific approach may facilitate approach selection. This study sought to compare the nuances of an extended version of the minipterional craniotomy (EMPT) with those of the transorbital endoscopic approach (TOEA) to the anterior and middle cranial fossae (ACF and MCF, respectively).

OBJECTIVE

To quantitatively analyze and compare the area of exposure and surgical freedom between EMPT and TOEA to the ACF and MCF.

METHODS

EMPT and TOEA were carried out in 5 latex-injected cadaveric heads, bilaterally (10 sides). For each approach, the area of exposure, surgical freedom, and angle of attack were obtained with neuronavigation and statistically compared.

RESULTS

No significant difference was found between the mean area of exposure of EMPT and TOEA at the ACF and MCF (P = .709 and .317, respectively). The mean exposure area at the ACF was of 13.4 ± 2.6 cm2 (mean ± standard deviation) and 13.0 ± 1.9 cm2 for EMPT and TOEA, respectively. Except for the crista galli, EMPT afforded a larger area of surgical freedom at all targets. EMPT also achieved significantly greater attack angles in vertical axis except to the crista galli. The horizontal attack angles to all targets were similar between approaches.

CONCLUSION

EMPT and TOEA offer a comparable area of exposure at the ACF and MCF in the cadaver; however, the instrument maneuverability afforded by EMPT is superior. Further studies are necessary to better define their precise surgical application.

Computational fluid dynamics after endoscopic endonasal skull base surgery-possible empty nose syndrome in the context of middle turbinate resection

BACKGROUND

Empty nose syndrome (ENS) is a rare and debilitating disease with a controversial definition, etiology, and treatment. One puzzling fact is that patients who undergo an endoscopic endonasal approach (EEA) often have resection of multiple anatomic structures, yet seldom develop ENS. In this pilot study, we analyzed and compared the computational fluid dynamics (CFD) and symptoms among post-EEA patients, ENS patients, and healthy subjects.

METHODS

Computed tomography scans of 4 post-EEA patients were collected and analyzed using CFD techniques. Two patients had significant ENS symptoms based on results of the Empty Nose Syndrome 6-item Questionnaire (score >11), whereas the other 2 were asymptomatic. As a reference, their results were compared with previously published CFD results of 27 non-EEA ENS patients and 42 healthy controls.

RESULTS

Post-EEA patients with ENS symptoms had a similar nasal airflow pattern as non-EEA ENS patients. This pattern differed significantly from that of EEA patients without ENS symptoms and healthy controls. Overall, groups with ENS symptoms exhibited airflow dominant in the middle meatus region and a significantly lower percentage of airflow in the inferior turbinate region (EEA with ENS, 17.74 ± 4.00% vs EEA without ENS, 51.25 ± 3.33% [t test, p < 0.02]; non-EEA ENS, 25.8 ± 17.6%; healthy subjects, 36.5 ± 15.9%) as well as lower peak wall shear stress (EEA with ENS, 0.30 ± 0.13 Pa vs EEA without ENS, 0.61 ± 0.03 Pa [p = 0.003]; non-EEA ENS, 0.58 ± 0.24 Pa; healthy subjects, 1.18 ± 0.81 Pa).

CONCLUSION

These results suggest that turbinectomy and/or posterior septectomy may have a varying functional impact and that ENS symptoms go beyond anatomy and correlate with aerodynamic changes. The findings open the door for CFD as a potential objective diagnosis tool for ENS.

Modified endoscopic endonasal approach with a minimally invasive transoral approach-an adjunct to infrapetrous approaches

OBJECTIVES/HYPOTHESIS

To evaluate the potential of a minimally invasive transoral-transpalatal approach (MITA) to the retrocarotid petrous apex, as an adjunct to endoscopic endonasal approaches (EEAs).

STUDY DESIGN

Cadaver study.

METHODS

Five cadaveric specimens were dissected raising an inverted U-shaped palatal mucoperiosteal flap, and drilling a rectangular palatotomy (between the greater palatine foramens, and just anterior to the palatine aponeurosis). This allowed a transpterygoid EEA with cross-court access (contralateral line of sight), followed by an extradural clivectomy that exposed the petroclival junction bilaterally. Surgical targets were marked on the posterior and medial surface of the petrous internal carotid artery (ICA), at its anterior genu, midhorizontal portion, and posterior genu. For each target and approach, the surgical freedom and angles of approach (in the horizontal and vertical planes) were calculated and statistically compared.

RESULTS

Compared to EEA, the MITA resulted in greater surgical freedom for all targets, with the highest values at the anterior genu (1,661.37 mm² vs. 312.76 mm² , P <.001), and maintaining superiority in this regard all the way to the posterior genu (847.84 mm³ vs. 138.91 mm³ , P < .005). MITA also offered greater angles of approach for all targets.

CONCLUSIONS

This study suggests that the MITA may be indicated to supplement the exposure provided by a transpterygoid EEA. This technique, associated with low potential morbidity, offers an alternative to internal carotid lateralization while managing extradural lesions that are adjacent to the petrous ICA.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:339-343, 2019.

Surgical simulation of a catastrophic internal carotid artery injury: a laser-sintered model

BACKGROUND

The catastrophic and rare nature of an internal carotid artery (ICA) injury during endonasal surgery limits training opportunities. Cadaveric and animal simulation models have been proposed, but expense and complicated logistics have limited their adoption. Three-dimensional (3D) printed models are portable, modular, reusable, less costly, and proven to improve psychomotor skills required for managing different lesions. In this study we evaluate the role of a simplified laser-sintered model combined with standardized training in improving the effectiveness of managing an ICA injury endoscopically.

METHODS

A 3-mm defect was created in the parasellar carotid canal of a laser-sintered model representing a sphenoid sinus. Artificial blood was directed to simulate the copious bleeding arising from an ICA injury. Twenty otolaryngologists and 26 neurosurgeons, with varying training and experience levels, were individually asked to stop the "bleeding" as they would in a clinical scenario, and provided no other instructions. This was followed by individualized formative training and a second simulation. Volume of blood loss, time to hemostasis, and self-assessed confidence scores were compared.

RESULTS

At the end of the study, time to hemostasis was reduced from 105.49 seconds to 40.41 seconds (p < 0.001). The volume of blood loss was reduced from 690 to 272 mL (p < 0.001), and the confidence scores increased in 95.7% of participants, from an average of 3 up to 8.

CONCLUSION

This ICA injury model, along with a formal training algorithm, appears to be valuable, realistic, portable, and cost-effective. Significant improvement in all parameters suggests the acquisition of psychomotor skills required to control an ICA injury.

Endonasal anatomy of the olfactory neural network: Surgical implications

OBJECTIVES/HYPOTHESIS

Define the anatomic distribution of the olfactory filaments within specific mucosal regions of the nasal cavity.

STUDY DESIGN

Cadaveric study.

METHODS

Seventeen cadaveric specimens (34 sides) were dissected to study the anatomical distribution and density of olfactory fila within different regions of the nasal cavity. Olfactory fila were dissected retrogradely to their point of entry into the anterior cranial fossa through the cribriform plate. Anatomic relationships among various components of the olfactory system and their corresponding arterial supply were determined subjectively.

RESULTS

The highest density of olfactory fila was found at the mucosa of the ethmoid roof and superior turbinates. Olfactory fila were found at regions not previously considered to be part of the olfactory system: lateral wall of the nose, ethmoidal bullae, and between the os sphenoidale and arc of the posterior choana. Furthermore, at the septum, 20% of the olfactory fila crossed contralaterally before exiting the nose. The anterior ethmoidal arteries were the primary blood supply to the olfactory epithelium.

CONCLUSIONS

This study suggests that olfactory filaments extend beyond previously established boundaries. These findings may have clinical implications regarding oncologic resections and could serve as the foundation for the development of techniques that better preserve olfactory function.

LEVEL OF EVIDENCE

NA Laryngoscope, 2473-2477, 2018.

Endoscopic Endonasal Focal Transclival-Medial Condylectomy Approach for Resection of a Foramen Magnum Meningioma: 2-Dimensional Operative Video

The endoscopic endonasal approach (EEA) provides direct access to foramen magnum meningiomas; however, it often requires extensive exposure including septal flap elevation with septum removal, complete sphenoidotomy, and panclivectomy.

We present a case of a 54-yr-old-female with an incidental foramen magnum lesion followed up with serial imaging who presented 10 mo later with progressive neck discomfort and episodes of dizziness, with confirmed tumor progression and further brainstem compression. A focal transclival EEA with medial condylectomy was performed preserving the upper two-thirds of the clivus, the nasal septum, and the sphenoid sinus. Gross total removal of a meningioma WHO Grade-1 was achieved with dura resection on the majority of the tumor (Simpson 2). Closure was achieved with a random pedicled inverted V nasaopharyngeal flap. There were no complications, all symptoms improved, and no recurrence was seen in 12 mo of follow-up.

IRB approval was neither required nor saught for this single case report. The patient gave informed consent.

Endoscopic endonasal approaches for the management of skull base meningiomas: selection criteria and clinical outcomes

BACKGROUND

Meningiomas are the most common primary intracranial tumor, arising from different locations, including the skull base. Despite advances in adjuvant treatments, surgical resection remains the main and best treatment for meningiomas. New surgical strategies, such as the endoscopic endonasal approach, have greatly contributed in achieving maximum and total safe resection, preserving the patient's neurological function.

METHODS

Based on the senior authors large experience and a review of the current literature, we have compiled this paper.

RESULTS

We review the surgical technique used at our institution and the most relevant aspects of patient selection when considering resecting a skull base meningioma using the the EEA. Further consideration is given to some skull base meningiomas arising from specific locations with some case examples.

CONCLUSIONS

The EEA is not an ideal approach for every skull base meningioma. Careful evaluation of the neurovascular structures surrounding the tumor is imperative to select the appropriate surgical corridor for a safe resection. Nevertheless, for appropriately selected cases, the endoscopic technique is a very valuable tool with some evidences of being superior to the microscopic transcranial approach. A dual-trained surgeon, in both endoscopic and transcranial approaches, is the best alternative to achieve the best patient outcome.

Analysis of the far-medial transoral endoscopic approach to the infratemporal fossa

OBJECTIVES/HYPOTHESIS

To demonstrate anatomic relationships of the far-medial transoral endoscopic assisted approach (FMT-EAA) to the infratemporal fossa (ITF) and define the corridor dimensions, surgical freedom, and limitations associated with this approach.

STUDY DESIGN

Cadaveric study.

METHODS

Twenty ITFs (10 specimens) were dissected with the assistance of 0 °, 30 °, and 45 ° rod-lens endoscopes. Image guidance was used to confirm and measure the corridors' structural boundaries and document the anatomical relationships encountered in this approach.

RESULTS

Access to the ITF via the FMT-EAA can be divided into two secondary surgical corridors: the superomedial and inferolateral triangles, each of which provides access to different areas. The superomedial triangle is bounded medially by the lateral pterygoid plate and posterolateral maxillary sinus wall, superiorly by the greater sphenoid wing, and inferolaterally by the lateral pterygoid muscle. The inferolateral triangle is bounded superiorly by the lower head of the lateral pterygoid muscle, inferiorly by the medial pterygoid muscle, and laterally by the mandible. Using a standard 19-mm endoscope, the FMT-EAA achieves a mean surgical freedom of 231 mm and 161 mm in the vertical and horizontal planes, respectively.

CONCLUSIONS

FMT-EAA adequately exposes critical structures of the ITF. This technique is a viable option for the management of selected ITF lesions, either alone or in combination with alternative minimally invasive approaches to the region.

LEVEL OF EVIDENCE

NA Laryngoscope, 128:2273-2281, 2018.

Comparative Analysis Between Lateral Orbital Rim Preservation and Osteotomy for Transorbital Endoscopic Approaches to the Cavernous Sinus: An Anatomic Study

BACKGROUND

Transorbital endoscopic approach (TOEA) to the cavernous sinus (CS) is a novel surgical technique. However, the necessity of lateral orbital rim (LOR) osteotomy is questionable.

OBJECTIVE

To illustrate the surgical dissection of TOEAs to CS and to investigate the additional benefit of LOR osteotomy.

METHODS

Anatomic dissections were carried out in 7 cadaveric heads (14 sides). The TOEAs were performed before and after LOR osteotomy; herein referred as the lateral transorbital approach (LTOA) and the lateral orbital wall approach (LOWA), respectively. The stereotactic measurements of the area of exposure, surgical freedom, and angles of attack around CS were quantified.

RESULTS

LOWA increased larger area of exposure than LTOA at entry site (5.3 ± 0.6 cm2 and 2.6 ± 0.6 cm2, respectively; P &lt; .001) but both of these techniques provided similar area of exposure at the surgical target site. With regard to the surgical freedoms, those afforded by LOWA were all significantly superior at all of the surgical targets with the difference ranged from 106.6% to 172.5%. No significant differences were found between the vertical angles produced by either approach. On the other hand, the horizontal angles achieved by LOWA were significantly more favorable.

CONCLUSION

The TOEAs, either with or without LOR osteotomy are feasible for CS exposure. Although the incremental effect of maneuverability is attained following the LOR osteotomy, it should be performed selectively. Additional research is needed to further validate the safety and efficacy, as well as for precisely defining the clinical application of these techniques.

Giant Olfactory Groove Meningioma—2-Staged Approach: 2-Dimensional Operative Video

A 42-yr-old female presented with an olfactory groove meningioma causing progressive vision loss and anosmia. Given the size of the tumor, we opted for a 2-stage surgery: endoscopic endonasal approach (EEA) followed by a craniotomy. Stage I surgery was a transcribriform transplanum EEA using a binostril 4-hand/2 surgeons (ENT and neuro) technique, with the patient positioned supine with the head slightly turned to the right side and tilted to the left, fixed in a 3-pin head clamp, under imaging guidance, in which we drilled out all the affected skull base bone, devascularized and debulked the tumor. Stage II surgery was done through a right frontotemporal craniotomy 2 mo later. The surgery and postoperative period was uneventful with no complications and no need for further reconstruction of the skull base. The patient's vision was normalized. Postoperative magnetic resonance imaging (MRI) confirmed a Simpson Grade 1 resection.

 The rationale behind this staged approach is that we have found when using a transcranial 1-stage approach the brain edema and necessary retraction required for resection leads to brain injury, oftentimes readily identified in the diffusion-weighted imaging MRI which are associated with different degrees of cognitive impairment. The skull base bone involved is usually not removed via transcranial approaches.

 Despite requiring a second surgery, this staged approach allows a true total resection (including the affected bone) and in the transcranial stage the brain is more relaxed, with less edema, reducing the need for retraction, which may lead to a better outcome.

 The patient has given assent and written consent for videos, images, or clinical or genetic information to be published.

Endoscopic Endonasal Approach to a Suprasellar Craniopharyngioma

We present the case of a 57-year-old male who presented with progressive right side vision loss whose workup revealed a large suprasellar lesion with invasion of the third ventricle. The pituitary stalk was not visible.

Hormonal panel showed no hormonal deficits. The initial diagnosis was of a type II transinfundibular craniopharyngioma (as classified by Kassam et al).

An endoscopic endonasal transplanum transtuberculum approach was done using a standard binostril four-hand technique, with the patient positioned supine with the head turned to the right side and tilted to the left, fixed in a three-pin head clamp, under imaging guidance. The tumor was carefully dissected away from the optic apparatus while preserving the vessels, mainly the superior hypophyseal artery. The stalk was identified around the tumor and preserved. The third ventricle was entered and inspected at the end of the procedure and a near-total resection (a small residual in the right hypothalamus) with decompression of the optic apparatus was achieved. Reconstruction was done in a multilayered fashion, using collagen matrix and a nasoseptal flap. Patient had an uneventful postoperative stay and was discharged on POD 4, neurologically stable with no hormonal deficits. Pathology confirmed an adamantinomatous craniopharyngioma. Due to a small growth of the residual, patient underwent fractionated stereotactic radiation (50.4Gy in 28 sessions). He presented with panhypopituitarism 2 years after radiation therapy. At 3-month follow-up, his vision was back to normal and 6-year postoperative magnetic resonance imaging showed no signs of recurrence.

The link to the video can be found at: https://youtu.be/chG7XIz7a_A .

Endoscopic Endonasal Resection of a Suprasellar Pituitary Adenoma Mimicking Tuberculum Sellae Meningioma in a Patient with an Intrasellar Persistent Trigeminal Artery

A 50-year-old female with an incidentally diagnosed suprasellar lesion was initially managed conservatively due to the presence of an intrasellar persistent trigeminal artery going through the dorsum sellae and fundamentally forming the blood supply of the entire posterior circulation. Serial follow-up brain magnetic resonance imaging (MRI) revealed progressive enlargement of the suprasellar lesion over 4 years period. Surgery was indicated after the initial tumor growth; however, the patient refused surgery for fear of complications related to the persistent trigeminal artery. Two-and-a-half years later, she presented with deterioration of vision. Formal visual field testing revealed a right temporal field defect. Brain MRI demonstrated significantly enlarged suprasellar lesion, most consistent with tuberculum sellae meningioma, exerting mass effect on the optic apparatus. The patient underwent endoscopic endonasal resection of the lesion through a transplanum/transtuberculum approach. Intraoperatively, absence of hypertrophic McConnel arteries, hyperostosis, and the fact that the dura was soft and not under tension was against the diagnosis of tuberculum sellae meningioma. Additionally, the tumor consistency was similar to a pituitary adenoma. A complete resection was accomplished and multilayer skull base reconstruction was performed with no complications. On postoperative day 1 (POD 1), she was operated upon for the evacuation of small suprasellar hematoma associated with vision deterioration. Histopathological examination confirmed the diagnosis of atypical pituitary adenoma with K_i -67 labeling index of 4 to 5%. The patient ultimately recovered well with improved vision, and was discharged on POD 4 with no new neurological deficits. At 4 years follow-up, her vision was normalized and brain MRI showed no residual or recurrent lesion. The link to the video can be found at: https://youtu.be/QZmzctjAEbw .

Investigation of the abnormal nasal aerodynamics and trigeminal functions among empty nose syndrome patients

BACKGROUND

Abnormal nasal aerodynamics or trigeminal functions have been frequently implicated in the symptomology of empty nose syndrome (ENS), yet with limited evidence.

METHODS

Individual computed tomography (CT)-based computational fluid dynamics (CFD) was applied to 27 ENS patients to simulate their nasal aerodynamics and compared with 42 healthy controls. Patients' symptoms were confirmed with Empty Nose Syndrome 6-item Questionnaire (ENS6Q), 22-item Sino-Nasal Outcome Test (SNOT-22), and Nasal Obstruction Symptom Evaluation (NOSE) scores. Nasal trigeminal sensitivity was measured with menthol lateralization detection thresholds (LDTs).

RESULTS

ENS patients had significantly lower (∼25.7%) nasal resistance and higher (∼2.8 times) cross-sectional areas compared to healthy controls (both p < 0.001). Despite inferior turbinate reductions, CFD analysis demonstrated that ENS patients had increased airflow concentrated in the middle meatus region (66.5% ± 18.3%) compared to healthy controls (49.9% ± 15.1%, p < 0.0001). Significantly less airflow (25.8% ± 17.6%) and lower peak wall shear stress (WSS) (0.58 ± 0.24 Pa) were found in the inferior meatus (vs healthy: 36.5% ± 15.9%; 1.18 ± 0.81 Pa, both p < 0.05), with the latter significantly correlated with the symptom scores of ENS6Q (r = -0.398, p = 0.003). Item-wise, complaints of "suffocation" and "nose feels too open" were also found to be significantly correlated with peak WSS around the inferior turbinate (r = -0.295, p = 0.031; and r = -0.388, p = 0.004, respectively). These correlations were all negative, indicating that less air-mucosal stimulations resulted in worse symptom scores. ENS patients (n = 12) also had impaired menthol LDT when compared to healthy controls (p < 0.0001).

CONCLUSION

This is the first CFD examination of nasal aerodynamics in a large cohort of ENS patients. The results indicated that a combination of loss of neural sensitivity and poorer inferior air-mucosal stimulation may potentially lead to ENS symptomology.

Endoscopic Endonasal Transtuberculum Sellae Approach for the Resection of Suprasellar Intrainfundibular Epidermoid Cyst

A 49-year-old female presented with intense headaches of 3 months duration. Brain magnetic resonance imaging (MRI) was performed and showed a sellar–suprasellar lesion extending into the third ventricle. A presumptive diagnosis of a craniopharyngioma was made. Since the patient did not have any visual deficits, she opted for conservative management. Four months later, she started to have progressive deterioration of vision; thus, surgery was indicated.

The patient underwent endoscopic endonasal resection of the lesion through a transtuberculum sellae approach. The patient was positioned supine with the head slightly extended and the face turned to the right side. Following the essence of a binostril four-hand technique, a total gross resection of the lesion was achieved and multilayer skull base reconstruction was performed utilizing collagen matrix and nasoseptal flap; with no intraoperative complications.

The patient's postoperative course was uneventful with the improvement in her vision, and she was discharged on postoperative day 4 with no new neurological deficits. Histopathological examination confirmed the diagnosis of an epidermoid cyst. Postoperative pituitary gland function was within normal limits except for mild diabetes insipidus for which she is on DDAVP 0.1 mg twice daily. At 4 years follow-up, the patient was doing well, her vision was normalized, and brain MRI revealed no evidence of residual or recurrent lesion.

The link to the video can be found at: https://youtu.be/OqDFpa_Xq78 .