Greater Palatine Canal: Computed Tomography-Based Anatomic Analysis And Clinical Significance for the Sinus and Skull Base Surgeon.

OBJECTIVE: Our aim is to describe the location and course of the greater palatine canal (GPC) by analyzing its relationship with anatomical landmarks that can be used during endoscopic sinus surgery. This information might help prevent injury to the neurovascular bundle. METHODS: A retrospective evaluation of paranasal sinus CT scans of 100 consecutive random patients, 200 sides, was performed. Five measurements related to the course of the GPC were conducted, from cranial to caudal. The anatomical landmarks were the inferior bony border of the sphenopalatine foramen to the cranial entrance of the GPC, the distance from the most dorsal, and inferior bony insertion of the middle turbinate and the inferior turbinate bones to the anterior margin of the GPC. The angle between the horizontal palatine bone and the GPC, its length, and the prevalence of osteophytes in GPC was also assessed. RESULTS: The mean distance of the inferior border of the sphenopalatine foramen to the cranial entrance of the GPC was 9.39 ± 1.72 mm. The mean distance of the dorsal insertion of the middle turbinate to the anterior margin of the GPC was 3.89 ± 0.93 mm. The distance of the dorsal insertion of the inferior turbinate to the anterior margin of the GPC was 3.16 ± 0.81 mm. The mean angle between the horizontal palatine bone and the GPC was 114.33 ± 10.92º and the mean length of the GPC was 30.23 ± 3.74 mm. None of the measurements showed a significant difference between the two sides. CONCLUSIONS: The landmarks used are easy to locate and assess on CT scans. These findings may help to make dissection safer in pathologies related to the pterygopalatine fossa, lateral sphenoid sinus or adjacent skull base.

Three-dimensional structure of the basal lamella of the middle turbinate.

The middle turbinate's basal lamella (3BL) is a variable landmark which needs to be understood in endoscopic transnasal skull base surgery. It comprises an anterior frontal and a posterior horizontal part and appears in its simplest depiction to be "L"-shaped, when viewed laterally. In this study we analyzed its 3D morphology and variations focusing on a precise and systematic description of the anatomy. CBCTs of 25 adults, 19 cadavers and 6 skulls (total: 100 sides) were investigated with the 3DSlicer software, creating 3D models of the 3BL. We introduced a novel geometrical classification of the 3BL's shape, based on segments. We analyzed their parameters and relationship to neighboring structures. When viewed laterally, there was no consistent "L"-shaped appearance of the 3BL, as it is frequently quoted. A classification of 9 segment types was used to describe the 3BL. The 3BLs had in average of 2.95 ± 0.70 segments (median: 3), the most frequent was the horizontal plate (23.05% of all segments), next a concave/convex plate (22.71%), then a sigma plate (22.37%). Further types were rare. We identified a horizontal plate in 68% of all lateral views whilst 32% of the 3BLs were vertical. A sigma-concave/convex-horizontal trisegmental 3BL was the most common phenotype (27%). Globally, the sigma-concave/convex pattern was present in 42%. The 3BL adhered the ethmoidal bulla in 87%. The segmenting method is eligible to describe the 3BL's sophisticated morphology.

Mixed response and mechanisms of resistance to larotrectinib in metastatic carcinoma ex pleomorphic adenoma of the parotid harboring an NTRK2 fusion: A case report.

INTRODUCTION: Standardized systemic treatment options are lacking for carcinoma ex pleomorphic adenoma, which is a rare and aggressive tumor primarily found in salivary glands.Here we report the case of a 63-year-old male with carcinoma ex pleomorphic adenoma of the left parotid and parapharyngeal space harboring a neurotrophic receptor tyrosine kinase (NTRK) 2 fusion who was treated with a small molecule inhibitor that targets the tropomyosin receptor kinase (TRK) proteins. To the best of our knowledge, no similar case has been described in the literature so far. PATIENT CONCERNS: After multiple surgical resections and radiotherapy for localized cancer disease over several years, our patient again developed an increasing swelling and pain around the left ear and numbness of the left half of the face. DIAGNOSIS: Magnetic resonance imaging and positron emission tomography/computed tomography scans showed tumor recurrence in the left parotid, below the left ear, and in the parapharyngeal space, as well as metastases of the lungs and cervical lymph nodes. As data on the efficacy of systemic therapies for inoperable carcinoma ex pleomorphic adenoma are scarce, we performed a next-generation sequencing that revealed the presence of a hitherto unknown NTRK2 fusion. INTERVENTIONS: Treatment with the TRK inhibitor larotrectinib was initiated, which induced rapid symptom improvement. However, part of the tumor had to be removed shortly afterwards due to local progression. Molecular testing did not demonstrate any alterations accounting for resistance to larotrectinib, with maintenance of the NTRK2 fusion. OUTCOMES: Three months later, imaging confirmed mixed response. While the reason for this remains unknown, the patient is in good condition and continues to receive larotrectinib. CONCLUSION: It remains unclear why our patient showed mixed response to larotrectinib and further studies are needed to explore other possible mechanisms of resistance.

3D endoscopy shows enhanced anatomical details and depth perception vs 2D: a multicentre study.

PURPOSE: The current standard endoscopic technique is a high resolution visualisation up to Full HD and even 4 K. A recent development are 3D endoscopes providing a 3-dimensional picture, which supposedly gives additional information of depth, anatomical details and orientation in the surgical field. Since the 3D-endoscopic technique is new, little scientific evidence is known whether the new technique provides advantages for the surgeon compared to the 2D-endoscopic standard technique in FESS. This study compares the standard 2D-endoscopic surgical technique with the new commercially available 3D-endoscopic technique. METHODS: The prospective randomized interventional multicenter study included a total of 80 referred patients with chronic rhinosinusitis with and without polyps without prior surgery. A bilateral FESS procedure was performed, one side with the 2D-endoscopic technique, the other side with the 3D-endoscopic technique. The time of duration was measured. Additionally, a questionnaire containing 20 items was completed by 4 different surgeons judging subjective impression of visualisation and handling. RESULTS: 2D imaging was superior to 3D apart from "recognition of details", "depth perception" and "3D effect". For usability properties 2D was superior to 3D apart from "weight of endoscopes". Mean duration for surgery was 26.1 min for 2D and 27.4 min. for 3D without statistical significance (P = 0.219). CONCLUSION: Three-dimensional endoscopy features improved depth perception and recognition of anatomic details but worse overall picture quality. It is useful for teaching purposes, yet 2D techniques provide a better outcome in terms of feasibility for routine endoscopic approaches.

Preoperative risk assessment for ambulatory sinonasal surgery.

OBJECTIVES: An increasing proportion of patients who are candidates for endoscopic sinus surgery can be treated as an outpatient. A preoperative risk assessment is needed to evaluate eligibility for day surgery. This study analyses the effectiveness of a risk assessment scoring system which examines medical, procedure-related, and socioeconomic factors. DESIGN: Prospective multicenter study. SETTING: Three center study including Klinik Hirslanden, Zurich, Switzerland, Luzerner Kantonsspital, Lucerne, Switzerland and HNO-Klinik München-Bogenhausen, Munich, Germany. PARTICIPANTS: Patients with endoscopic sinus procedures between January 1st, 2017 and December 31st, 2018. MAIN OUTCOME MEASURES: The "day surgery risk score" consisted of three subgroups with medical, procedure-related and socioeconomic risk factors were assessed to determine if these predicted the severity of postoperative complications. RESULTS: Three-hundred and one patients who underwent endoscopic sinus surgery were included. The score resulted in a median value of 5 [5, 5]. In the Receiver-Operating Curve (ROC-the true-positive rate against the false-positive rate), the Area Under the Curve (AUC) was 0.59 with 95% confidence interval from 0.49 to 0.69, indicating that the "day surgery risk score" may be no better at predicting the likelihood of a complication than a random classification model. CONCLUSIONS: The "day surgery risk score" is a straightforward risk assessment which combines medical, procedure-related, and socioeconomic factors. The score is easy to use but in trying to decide whether a patient is eligible for ambulatory endoscopic sinus surgery it did not predict whether a complication was more likely to occur.

Endoscopic unilateral transethmoid-paraseptal approach to the central skull base.

Objectives: The endoscopic technique in transnasal skull base surgery offers optimal visualization and free manipulation in the surgical field. However, it may cause approach-related sinonasal injury, influencing patients' quality of life (QOL). To minimize rhinological morbidity without restrictions in surgical manipulation and tumor resection, we introduced the unilateral transethmoidal-paraseptal approach. In this article, we analyzed the long-term results and sinonasal outcome of this technique. Study Design: Retrospective analysis of medical records. Methods: Forty-two consecutive patients underwent surgery between June 2010 and March 2014 using the transethmoid-paraseptal approach. Perioperative work-up included neurological, radiological, endocrinological, ophthalmological, and rhinological analysis. Patients' preoperative, 1-month and 1-year postoperative QOL was measured using the Sino-Nasal Outcome Test (SNOT-22). Results: At all individuals, a unilateral transethmoid-paraseptal approach was performed. Removal of the turbinates, posterior septal resection or a conversion to biportal surgery could be avoided in all cases. There were no intraoperative neurovascular complications. All patients had a notable improvement in any disease-related symptoms, as well as by objective criteria. Complete tumor resection was aimed in 39 cases and achieved in 31 of them. The SNOT-22 scores transiently worsened 1 month after surgery and non-significantly improved after 1 year, compared with the preoperative status. A subgroup of 7 patients with preoperative sinonasal disease evidence showed continuous significant improvement (p < .05) of SNOT-22 scores across time. The smell screening tests showed no significant difference across time. Conclusion: The described approach allows safe removal of various skull base lesions without deterioration in sinonasal QOL and smell function. Level of Evidence: 4.

How I do it: the mononostril endonasal transethmoidal-paraseptal approach.

BACKGROUND: The use of endoscopes in transnasal surgery offers increased visualization. To minimize rhinological morbidity without restriction in manipulation, we introduced the mononostril transethmoidal-paraseptal approach. METHODS: The aim of the transethmoidal-paraseptal approach is to create sufficient space within the nasal cavity, without removal of nasal turbinates and septum. Therefore, as a first step, a partial ethmoidectomy is performed. The middle and superior turbinates are then lateralized into the ethmoidal space, allowing a wide sphenoidotomy with exposure of the central skull base. CONCLUSIONS: This minimally invasive transethmoidal-paraseptal approach is a feasible alternative to traumatic transnasal concepts with middle turbinate and extended septal resection.

The effect of "Pyriform Turbinoplasty" on nasal airflow using a virtual model.

BACKGROUND: A new procedure, pyriform turbinoplasty, is described and nasal airflow is measured before and after this procedure in a virtual model. METHODOLOGY: Pyriform turbinoplasty is the submucosal reduction of the bone of the frontal process of the maxilla and the lacrimal bone. It opens part of the lateral margin of the nasal valve area with minimal damage to nasal mucosa. The resection of bone in this area can be extended by "nasal wall lateralization" when the lacrimal bone that joins the uncinate process behind the lacrimal duct as well as the base of the inferior turbinate and the edge of the maxilla at the rim of the pyriform aperture are removed. Nasal airflow was simulated using computational fluid dynamics and ANSYS Fluent solver. RESULTS: Analysis using fluid dynamics showed that these procedures help ventilation in the main airflow areas without substantially altering the normal pattern of airflow. CONCLUSIONS: The changes after performing a pyriform turbinoplasty seem to be an improvement when compared to the changes after inferior turbinate surgery that can misdirect the airflow largely through the inferior meatus.

Combined transnasal and transcranial removal of a giant clival chordoma.

Clival chordomas confront the surgeon with the task of resecting an aggressively invasive and destructive tumor in a critical surrounding. For many, mainly smaller, chordomas, the transnasal transclival approach is a feasible and safe surgical access. Larger tumors and especially those with extensive intradural, retrochiasmal, and/or deep cervical expansion are mostly approached by open craniotomy. Staged procedures are also commonly used in the case of expansive tumor growth. We present the first case of a single-session combined transnasal and transcranial approach to radically resect a large clival chordoma.

Evaluation of an anatomic model of the paranasal sinuses for endonasal surgical training.

OBJECTIVES: To assess the suitability of a new anatomic model of the paranasal sinuses for endonasal surgical training. STUDY DESIGN: Prospective observational pilot study. METHODS: A new anatomic model of the paranasal sinuses was developed by the Department of Anatomy at the University of Zurich. The practicability of the model was evaluated by three experienced endoscopic sinus surgeons with a special focus on its possible use in training. Standardized surgical procedures were performed under simulated real-life conditions in the operating theatre. RESULTS: The endoscopic appearance of the nasal airway closely resembled real human tissue and the detailed anatomy of the model allowed the same structured surgical steps to be performed as in real life in the absence of bleeding. CONCLUSION: This anatomic model is a readily available teaching tool for endoscopic sinus surgeons.

The anatomy of the sphenopalatine artery for the endoscopic sinus surgeon.

BACKGROUND: This study was performed to determine the variations in the branching pattern of the sphenopalatine artery medial to the crista ethmoidalis. Seventy-seven cadaver head sides that had been sectioned sagittally in the midline with their septum removed were used after injecting pink latex to highlight the arterial vessels. METHODS: The mucosa from the middle meatus from the level of the basal lamella was removed until the artery and its branches were seen and then was examined under the microscope to identify the position of the arterial branches. RESULTS: The sphenopalatine artery and its branches were identified in 75 specimens. Of these 75 specimens, 73 (97%) had 2 or more branches medial to the crista ethmoidalis, 49 (67%) had 3 or more branches, 26 (35%) had 4 or more branches, and 1 specimen had 10 branches. In two specimens the artery presented as a single trunk. CONCLUSION: The sphenopalatine artery normally starts to branch lateral to the crista ethmoidalis and these branches vary widely. It is important that the surgeon who undertakes ligation or cautery of the artery is aware of these variations, otherwise they may overlook some of the branches. With an endoscopic approach, removal of the crista ethmoidalis helps visualize these branches.

Olfaction in rhinology--methods of assessing the sense of smell.

Olfactory disorders frequently occur in rhinological disease. Different subjective and objective test methods are available to assess the sense of olfaction. Among the subjective methods, screening tests and threshold measurements are commonly used to quantify hyposmia or anosmia. Qualitative methods are available using discrimination and identification tests. Objective methods are used in research and in some medicolegal situations. Objective tests include olfactory evoked potentials, functional Magnetic Resonance Imaging and functional Positron Emission Tomography. The measurement of the sense of smell helps to assess the whole spectrum of the effects of nasal disease. This is especially important before rhinological surgery, because a non-detected smell disorder in patients with rhinological disease is common. The assessment of a pre-existing hyposmia or anosmia helps to avoid a postoperative claim that this was caused by surgery. A variety of validated screening tests for olfaction is available and they are a useful tool to document whether a patient is able to smell.

Male subjects who could not perceive the pheromone 5a-androst-16-en-3-one, produced similar orbitofrontal changes on PET compared with perceptible phenylethyl alcohol (rose).

BACKGROUND: The aim of this study was to evaluate in how far cerebral blood flow changes in male subjects when exposed to a pheromone that they cannot consciously smell. METHODS: We used a boar taint steroid (5a-Androst-16-en-3-one), which is similar to human axillary sweat but could not be detected by the human volunteers who participated in this study. RESULTS: The pheromone produced activation of the orbitofrontal and frontal cortex in comparison to a baseline condition. The same regions were activated when the subjects smelled a rose-like odour. CONCLUSION: This study shows that a pheromone, which is not consciously detected, can evoke a response in the brain that is similar to a detectable odour.

Endoscopic sinus surgery: advantages of the bimanual technique.

BACKGROUND: The orthodox endoscopic sinus surgical technique is "one-handed," which means that the surgeon holds the endoscope in one hand and uses the free hand for other instruments or suction. This technique has its limitations. When there is a lot of bleeding or when tension needs to be kept on tissue so that it can be cut cleanly, this is best done using both hands. This "bimanual" technique was described > 10 years ago, and although it offers several advantages, it is rarely used. The main reason is the requirement for two trained endoscopists. In a prospective randomized interventional study, the duration of the operation using the one-handed technique as opposed to the bimanual technique was compared. METHODS: Patients undergoing endoscopic sinus surgery for chronic rhinosinusitis were evaluated. One side of the nose underwent the conventional one-handed technique, while the other side had the bimanual technique. The operation time for each side was noted. RESULTS: Fifty patients (31 men and 19 women) with a mean age of 47.6 years (22-80 years) were evaluated. The mean operation time with the one-handed technique was 39.3 minutes (9-93 minutes). With the bimanual technique, the mean operation time was 31.0 minutes (6-78 minutes). The reduction in operation time with the bimanual technique was 21% and was highly significant (p < 0.001). CONCLUSION: The bimanual endoscopic sinus surgery technique leads to a significant reduction in operation time. The patient may benefit from a shorter operation time and the surgeon has better visibility that may reduce the incidence of complications. Furthermore, there are potential economic advantages because of the increased efficiency of surgical time.

Objective assessment of tip projection and the nasolabial angle in rhinoplasty.

OBJECTIVE: To provide an objective method to measure the extent of nasal tip projection and the nasolabial angle. DESIGN: We retrospectively studied preoperative and postoperative images using a novel approach. The constant position of the cornea in lateral views and the diameter of the iris in frontal views were used to standardize and compare digitalized images of patients before and after surgery. We tested this objective assessment technique using the digitized slides of patients with saddle nose deformities and measured changes in their nasal tip projection and nasolabial angle. We included 63 patients who had undergone an open rhinoplasty with the I-beam technique by the same surgeon over a 7-year period. We tested the reproducibility of these measurements with 10 independent investigators. We also determined whether the measurements using this objective technique correlated with the surgeon's or patients' subjective assessments of the outcome. RESULTS: We were able to use the objective measurement technique in 42 patients (67%). It was not possible to use the technique in 21 patients (33%) because the photographic conditions had not been fulfilled. The measurement variability of 10 different investigators expressed as standard deviations in percentage of the mean value was 6.7% for nasal tip projection and 1.3% for the nasolabial angle. The surgeon's subjective assessment of the outcome correlated with the objective changes of nasal tip projection (P = .045) and the nasolabial angle (P = .045). There was no correlation between the patients' assessments and the objective measurements. CONCLUSIONS: The objective measurements tested were easy to use and investigator independent. They also correlated with the surgeon's assessment of outcome.