Cartilaginous Eustachian Tube Research Articles

CT features of abnormally whole-course wide eustachian tubes with microtia and atresia

Objective: To study the clinical and CT features of the abnormal whole-course wide of eustachian tube (AWWET) with microtia and atresia(MA). Methods: The clinical and CT data of 19 patients (20 ears) from January 2017 to December 2021 with AWWET with MA were retrospectively analyzed, including 15 males and 4 females. The age ranged from 5 to 16 years, with an average of 9.5 years. 50 patients with common MA without wide eustachian tube(ET) as a case control group, including 32 males and 18 females.The age ranged from 5 to 16 years, with an average of 9.2 years. 20 patients (40 ears) who had normal ear CT for tinnitus, otalgia as a normal control group, including 12 males and 8 females. The age ranged from 5 to 16 years, with an average of 12.5 years. We measured the dimension and length of the bony portion of the ET, the total length, the angle between the bony portion and the cartilage portion, and the horizontal angle of ET on CT imagings, and compared with 40 normal ears by SPSS 27.0 software. Results: According to the relationship between AWWET and tympanum, patients were divided into the communicated group and the blocked group. A male predominance, left ear predominance, with high incidence of hemifacial microsomia exhibited in both groups. AWWET was presented as a widened lumen on CT. In 11 ears (4 ears in the communicated group, 7 ears in the blocked group), ETs bifurcated, the upper bony tube extended to the sphenoid body, the lower part continued down to cartilaginous ET and opened onto the nasopharynx, with"mastoid-like"pneumatization of the sphenoid body in 6 ears. The middle ear deformity in case group was more serious than MA control group, especially the blocked group. The incidence of otitis media in the communicated group was lower than that in the MA control group, and 4 cases in the blocked group had effusion in the ET. Compaired with normal ear, the bony ET elongated significantly in the AWWET groups, and the whole course of ET was significantly shortened, specially in the blocked group. The angle between the bony ET and the cartilaginous ET was decreased and the horizontal angle of the ET increased in the AWWET groups, the difference was considered to indicate statistical significance(P<0.05). Conclusions: AWWET with MA is rare, a male predominance, left ear predominance, and with high incidence of hemifacial microsomia. The middle ear deformity is more serious than common MA, especially in the blocked group. The incidence of otitis media in the communicated group is significantly lower than that in the common MA, and the blocked group may be accompanied by ET inflammation.

Permanent occlusion of the Eustachian tube: a retrospective study on reopening procedures

PurposeThis study retrospectively evaluated the efficacy and versatility of reopening procedures for the permanent occlusion of the cartilaginous Eustachian tube (POET) by analyzing four consecutive cases.MethodsThe study included all patients diagnosed with POET who suffered from Eustachian tube occlusion and glue ear. A combined approach of endoscopic transnasal/transoral laser surgery was utilized to reopen the POET. This was subsequently followed by balloon dilation (BET) and stenting for a duration of six weeks. In one distinct case, the Eustachian tube orifice was approached via a transtympanic method, where a balloon catheter was placed. The primary outcome measures targeted the success rate of reopening, which was quantified using audiological outcomes and Eustachian tube patency verified by a positive Valsalva maneuver.ResultsFour patients, with an age range of 14–62 years (mean age of 29.3 years), were subject to Eustachian tube reopening. The duration of follow-up varied between 10 and 24 months, averaging at 16.2 months. Notably, 75% of the surgically treated ears displayed no evidence of glue ear upon their last follow-up and showed restoration of Eustachian tube patency. The procedures were executed without any surgical complications. The causes for POET in these patients were heterogeneous: two were attributed to scarring post adenoidectomy, one to occlusion following orthognathic surgery and the remaining one due to prior radiotherapy treatment for squamous cell carcinoma located at the soft palate.DiscussionTotal occlusion of the cartilaginous Eustachian tube may be linked to persistent middle ear diseases. It is imperative to conduct nasopharyngeal endoscopy in these cases. The findings from this study suggest that the Eustachian tube reopening procedure is predominantly effective and safe for patients with POET stemming from a variety of pathologies. Future research should focus on exploring advanced stenting devices and necessitate longer follow-up periods for comprehensive understanding.

Multiparametric Measurements of the Eustachian tube and Peritubal Region Using Computed Tomography as a Preoperative Workup for Tuboplasty.

Eustachian tube dysfunction (ETD) is considered a causative factor for middle ear disease as well as treatment failure. The pathogenesis may be a result of chronic infection, allergy, laryngopharyngeal reflux, primary mucosal disease, dysfunction of the dilation mechanism and anatomical obstruction. Hence, it becomes essential to know the structure and anatomical variations of the Eustachian tube(ET), particularly with the advent of novel therapeutic options such as tuboplasty to ensure optimal therapeutic outcome. This cross-sectional study is done to perform multiparametric measurements of the ET and peritubal region using computed tomography and develop a structured protocol for pre-tuboplasty workup. This study was done for a period of 20 months, in 100 normal subjects aged between 18 and 60 years, who underwent computed tomography (CT) study of the head and face region, for indications other than nasal/ pharyngeal and sinus disease. The mean bony, cartilaginous and overall ET lengths were higher in males. In females, the mean ET angles with Reid's plane were higher. Higher mean craniocaudal diameters of the ET lumen were observed in males. Carotid canal dehiscence was seen in equal prevalence on both sides (5%), with no significant gender differences. Therapeutic interventions such as eustachian tuboplasty will benefit from preoperative imaging based planning. This structured protocol provides standardization of pre-operative workup for tuboplasty.

Surgical Closure of the Eustachian Tube Through Middle Fossa and Transmastoid Approaches: A Pilot Cadaveric Anatomy Study.

Cerebrospinal fluid rhinorrhea after temporal bone surgery involves drainage from the Eustachian tube (ET) into the nasopharynx, causing significant patient morbidity. Variable anatomy of the ET accounts for failures of currently used ET obliteration techniques. To describe the surgical anatomy of the ET and examine possible techniques for ET closure through middle fossa (MF) and transmastoid approaches. We described the surgical anatomy of the ET from the MF and transmastoid approaches in 5 adult cadaveric heads, measuring morphometric and surgical anatomy parameters and establishing targets for definite ET obliteration. The osseous ET measured an average of 19.53 mm (±1.56 mm), with a mean diameter of 2.24 mm (±0.29 mm). The shortest distance between the greater superficial petrosal nerve and the ET junction was 6.61 mm (±0.61 mm). Shortest distances between the ET junction and the foramen spinosum and posterior border of the foramen ovale were 1.09 mm (±0.24 mm) and 2.03 mm (±0.30 mm), respectively. Closure of the cartilaginous ET may be performed by folding it in on itself, securing it by packing, suturing, or surgical clip ligation. Definite obliteration of the cartilaginous ET appears feasible and the most definite approach to eliminate egress of cerebrospinal fluid to the nasopharynx using the MF approach. This technique may be used as an adjunct to skull base procedures where ET closure is planned.

Reconstruction of the Obliterated Eustachian Tube: A Pilot Case Series.

To investigate the safety and early efficacy of a procedure for reconstruction of the obliterated Eustachian tube (ET). Retrospective case series. Patients with total obliteration of the cartilaginous ET, with intractable mucoid effusion causing repeated occlusion of tympanostomy tubes were included. Patients underwent endoscopic transnasal/transoral reconstruction of the obliterated ET using transtympanic illuminated guidewire guidance. A temporary stent (angiocatheter filled with bonewax) was placed to maintain patency while healing. In four cases an additional steroid-eluting propel stent was placed in the ET orifice. Main outcome measures were otomicroscopy results, absence of middle ear effusion, and nasopharyngoscopy showing patency of the ET orifice. Nine ETs (seven patients), ages 17-68 years (mean 37.9) underwent ET reconstruction. Follow-up ranged from 4 to 56 months (mean 30.9 months). 89% of operated ears had no effusion at last follow-up. Two patients (three Eustachian tubes) underwent successful reoperation. There were no complications directly related to the procedure. Etiologies of obliteration included scarring after sinus surgery, obstruction after maxillo-mandibular advancement surgery (two patients), bullous pemphigus, gunshot trauma, and previous patulous obliteration (two patients). Complete occlusion of the cartilaginous ET can be associated with intractable mucoid effusion; endoscopic examination should be considered in such cases. In this pilot study, ET reconstruction was found to be a safe and possibly effective procedure in patients with total obliteration of the ET from various etiologies. Larger studies with long term follow up are indicated. 4 Laryngoscope, 133:1970-1975, 2023.

Exploration of anatomical landmarks for performing an endoscopic transoral nasopharyngectomy.

Performing a nasopharyngectomy via a transoral approach has been reported; however, defining landmarks to facilitate this approach has not been addressed. This study aims to explore anatomical landmarks to aid in performing a nasopharyngectomy via the transoral corridor. An endoscopic transoral nasopharyngectomy was performed on six cadaveric specimens (12 sides). Related anatomical landmarks were defined, and the strategy to preserve the parapharyngeal internal carotid artery (pICA) was explored. An endoscopic transoral nasopharyngectomy was successfully achieved in all 12 sides. Utilizing the pterygoid hamulus as a landmark, the cartilaginous ET and attachments could be adequately exposed. Identification of the pICA is a prerequisite prior to Eustachian tube (ET) transection. The sphenoidal spine and the petrotympanic fissure could be sufficiently revealed in all 12 sides, which aided in transection of the cartilaginous ET without pICA injury. The ET and the prevertebral contents could be adequately removed via the transoral corridor. The pterygoid hamulus, sphenoidal spine and petrotympanic fissure serve as reliable landmarks for performing a transoral nasopharyngectomy. Identification of the pICA is a prerequisite prior to transection of the ET to avoid pICA injury.

Serial histological changes in the cartilaginous eustachian tube in the rat following balloon dilation.

Although balloon dilation has shown promising results in the treatment of dilatory Eustachian tube (ET) dysfunction, the histological effects of ET balloon dilation (ETBD) is unknown because histological examination of the whole human cartilaginous ET is impossible. Animal studies are needed to elucidate the effect of ETBD so we evaluated the histological changes after ETBD in a rat model. The left ET of 20 Wistar rats was dilated with a balloon catheter and the right ET was used as a control. Five rats were sacrificed immediately after ETBD, at 1, 4 and 12 weeks after the procedure for histological examination. The epithelial cells, presence of epithelial hyperplasia, and the proportion of the goblet cells in the epithelium; the vascular structures and dimensions of the submucosa; and presence of cartilage fracture and the area of the ET lumen were evaluated and compared between the groups. Desquamation of nearly all epithelial cells and the fracture of tubal cartilages were observed immediately after ETBD. At 1-week post-ETBD, the ciliated epithelial cells started to recover with epithelial hyperplasia. The goblet cells recovered by 4 weeks post-ETBD and epithelial hyperplasia decreased but was still present at 12 weeks post-ETBD. The depth of the submucosa increased and neovascularization in this region was observed at 1-week post-ETBD and persisted up to 12 weeks post-ETBD. The lumen of the cartilaginous ET increased immediately after ETBD but decreased at 1-week post-ETBD. The cartilaginous ET lumen recovered to the normal value at 4 weeks post-ETBD. This study is the first to describe the serial histological changes to the cartilaginous ET after ETBD and helps our understanding of the histological changes that occur after an ETBD intervention for intractable ET dysfunction.

Measurements of The Pediatric Cartilaginous Eustachian Tube: Implications for Balloon Dilation.

(1) Measure the cartilaginous Eustachian tube (ET) length using a computed tomography (CT) scan and (2) develop a prediction model to measure this length without the need of a CT scan. CT measurements in children. Children's Hospital. CT scans were reformatted to project the cranial and caudal limits of the cartilaginous ET. The length was measured in 193 children who underwent a neck CT scan for nonotologic indications. Five physicians independently reviewed all or some of these measures. Four different models based on age, age ranges, weight, and height were created and compared to predict ET length. The cartilaginous ET length was 25.3 ± 3.1 mm for the right and for the left ear. The mean ET length for the females was statistically significantly less than the length in males. The lower ET lengths in children as old as 5 years of age were less than the 2cm adult criteria used for catheter insertion. All 4 models performed equally well in predicting ET length. Model number 4, which is based on height, was the easiest to calculate ET length. The cartilaginous portion of the pediatric ET can be measured with good precision using reformatted CT images. We caution against using the "adult" criteria of 2cm for catheter insertion in children, especially those younger than 5 years of age. We recommend using a model utilizing height measures to estimate ET length or direct measurements from a reformatted CT scan. NA Laryngoscope, 133:396-402, 2023.

An Endoscopic Endonasal Nasopharyngectomy with Posterolateral Extension.

Background Invasion depth influences the choice for extirpation of nasopharyngeal malignancies. This study aims to validate the feasibility of endoscopic endonasal resection of lesions with a posterolateral invasion. As a secondary goal, the study intends to propose a classification system of endoscopic endonasal nasopharyngectomy determined by the depth of posterolateral invasion. Methods Eight cadaveric specimens (16 sides) underwent progressive nasopharyngectomy using an endoscopic endonasal approach. Resection of the torus tubarius, Eustachian tube (ET), medial pterygoid plate and muscle, lateral nasal wall, and lateral pterygoid plate and muscle were sequentially performed to expose the fossa of Rosenmüller, petroclival region, parapharyngeal space (PPS), and jugular foramen, respectively. Results Technical feasibility of endonasal nasopharyngectomy toward a posterolateral direction was validated in all 16 sides. Nasopharyngectomy was classified into four types as follows: (1) type 1: resection restricted to the posterior or superior nasopharynx; (2) type 2: resection includes the torus tubarius which is suitable for lesions extended into the petroclival region; (3) type 3: resection includes the distal cartilaginous ET, medial pterygoid plate, and muscle, often required for lesions extending laterally into the PPS; And (4) type 4: resection includes the lateral nasal wall, pterygoid plates and muscles, and all the cartilaginous ET. This extensive resection is required for lesions involving the carotid artery or extending to the jugular foramen region. Conclusion Selected lesions with posterolateral invasion into the PPS or jugular foramen is amenable to a resection via expanded endonasal approach. Classification of nasopharyngectomy based on tumor depth of posterolateral invasion helps to plan a surgical approach.

Morphological Analysis of the Adult Eustachian Tube: A Fresh-Frozen Human Cadaver Study.

To evaluate the dilated Eustachian tube (ET) anatomy configuration using fresh human cadavers. Fourteen ears from human cadavers were used to identify the ET configuration. The cadaver head was cut in the sagittal plane parallel to the nasal septum, dividing it into right and left sides. Silicone was then inserted into the ET through the nasopharyngeal orifice (NO). The volume and length of the impression were measured using 3D computed tomography imaging. The ET lumen was found to narrow from the NO to the isthmus, and the ET surface was concave anteriorly and convex posteriorly. The lower portion of the ET lumen was the most dilated and displayed a narrow top. The average volume of the ET impression was 1.4 ± 0.5 ml. The total length of the posterior side was 30.5 ± 3.6 mm, and that of the anterior side was 26.3 ± 3.4 mm. The widest ET area of the NO was 10.1 ± 0.9 mm in height and 8.0 ± 1.5 mm in width. The preisthmus was 2.4 ± 0.4 mm in height and 1.3 ± 0.5 mm in width. The height and width were 8.37 and 5.33 mm at the 5 mm point from the NO, and 5.51 and 1.94 mm at the 20 mm point from the NO, respectively. We evaluated the configuration of the cartilaginous ET lumen, which is the main target of balloon dilation, and our findings may give insights into this dilation process and assist with the further development of ET balloons and stents.

Do morphological differences in orientation of the Eustachian tube and dilator tubae muscle distinguish populations with high rates of middle ear disease?

Middle ear disease or otitis media (OM) is among the most common pediatric conditions globally. It is nearly ubiquitous among every human population, usually occurring within the first three postnatal years. The etiology of OM is known to be rooted in the short, horizontal cartilaginous Eustachian tubes (CET) of infants which are mechanically inefficient relative to those of adults. Yet, despite the presence of OM among all human populations, Inuit and Aboriginal Australian communities have been documented as exhibiting some of the highest rates globally. Little information exists on the normal morphology of the bony nasopharyngeal boundaries of these groups. We tested whether they could be distinguished from other human populations in the orientation of the cartilaginous Eustachian tube and dilator tubae (DT) belly of the tensor veli palatini muscle (TVP), the sole dilatory apparatus of the CET. Any morphological feature distinguishing groups with higher rates of OM may impact susceptibility. We reconstructed soft tissue CET and DT morphology from adult dry crania. The sample represented eight populations: Alaska (n=156); Aleutian Islands (n=14); China (n=37); Greenland (n=28); Australia (n=39); Germany (n=22); India (n=15); and West Africa (n=19). Alaskans, Aleuts, Greenlanders, and Australians were considered populations with high rates of OM while the remainder were used as comparator populations with relatively lower documented rates of OM. We assessed morphology from coordinate data collected along the posterior edges of the medial pterygoid plates, the hard palate, the basicranial midline, and the osseous orifice of the Eustachian tube. Angular measures were assessed from the coordinate data and Bonferroni-Dunn-adjusted multiple t-tests were performed. Results showed that the Alaskans exhibited the most horizontal orientation of the DT relative to the axis of its common tendon with the TVP palatal sub-belly (an infant-like trait), being significantly more horizontal (P<0.05) than among all other groups. This trait could impact the function of the CET, especially among infants whose DT orientation would be even more horizontal. The only measure that distinguished Alaskans, Greenlanders, and Australians from all other populations was the sagittal orientation of the CET, an additional trait that may impact DT function. The presence of these morphological features may thus be related to increased rates of OM.

Identification of critical windows in early development of human upper respiratory tract and middle ear disease.

Otitis media (OM) or middle ear disease is a prevalent pediatric condition generally related to early growth of the cartilaginous Eustachian tube (CET). This study used a developmental series of dry crania to reconstruct CET and dilator tubae (DT, the muscle opening the CET) morphology. Timing and directionality of CET and upper respiratory tract (URT) growth were investigated. Traditional and 3D geometric morphometrics (GM) were used to assess bony landmarks on the crania. The series was divided using dental eruption into seven growth stages ranging from before eruption of deciduous dentition (approximately the first 6 postnatal months) to eruption of the first permanent maxillary molar (after approximately 6 years). Bony endpoints of the CET and DT were used to calculate their morphology. GM analysis showed substantial shape differences between newborns, early infants, and all later developmental stages. Univariate measures showed the largest growth change between birth and 6months. Subsequently, CET morphology changed little in the latter half of year 1, instead maturing gradually until approximately 3 years whereas DT relative length and orientation finish growth by the end of year 1. Incongruence in slower CET growth and faster DT growth could impact CET function between 6 and 12 months and be a contributing factor of OM. Tubal aeration may improve after this time when both CET and DT morphology mature, coinciding with clinically reported drop-off in ear infections.

Developmental Anatomy of the Eustachian Tube: Implications for Balloon Dilation.

To describe the developmental anatomy of the eustachian tube (ET) and its relationship to surrounding structures on computed tomography. Case series with chart review. A tertiary care hospital. ET anatomy was assessed with reformatted high-resolution computed tomography scans from 2010 to 2018. Scans (n = 78) were randomly selected from the following age groups: <4, 5 to 7, 8 to 18, and >18 years. The following were measured and compared between groups: ET length, angles, and relationship between its bony cartilaginous junction and the internal carotid artery and between its nasopharyngeal opening and the nasal floor. The distance between the bony cartilaginous junction and internal carotid artery decreased with age between the <4-year-olds (2.4 ± 0.6 mm) and the 5- to 7-year-olds (2.0 ± 0.3 mm, P = .001). The ET length increased among the <4-year-olds (32 mm), 5- to 7-year-olds (36 mm), and 8- to 18-year-olds (41 mm, P < .0001). The cartilaginous ET increased among the <4-year-olds (20 mm), 5- to 7-year-olds (25 mm), and 8- to 18-year-olds (28 mm, P < .0001). The ET horizontal angle increased among the <4-year-olds (17°), 5- to 7-year-olds (21°), and 8- to 18-year-olds (23°, P≤ .003), but the ET sagittal angle did not statistically change after 5 years of age. The height difference between the nasopharyngeal opening of the ET and the nasal floor increased among the <4-year-olds (4 mm), 5- to 7-year-olds (7 mm), and 8- to 18-year-olds (11 mm, P < .0001). The ET elongates with age, and its angles and relationship to the nasal floor increase. Although some parameters mature faster, more than half of the ET growth occurs by 8 years of age, and adult morphology is achieved by early adolescence.

Balloon Dilation for Obstructive Eustachian Tube Dysfunction in Children.

Determine the safety and efficacy of balloon dilation of the Eustachian tube (ET) in pediatric patients. Retrospective matched cohort study. Tertiary medical center. Pediatric patients (<18 yr) with persistent (>1.5 yr) chronic Eustachian tube dysfunction (ETD) with previous tympanostomy tube (TT) insertion versus matched controls. Balloon dilation of the cartilaginous ET (BDET) was performed using concomitant myringotomy with/without tube placement and adjunctive procedures if indicated versus controls (TT). Otitis media with effusion (OME)/retraction with need for additional tube, tympanogram, audiogram, otomicroscopy, ET mucosal inflammation/opening score, and Valsalva maneuver. Forty six ETs (26 patients), ages 7 to 17 years (mean 12.5) underwent BDET. Mean follow-up was 2.3 years (standard deviation [SD], 1.1; range, 6 mo-5 yr). Significant improvements were observed for all measures. Tympanic membranes were healthy in 9% preoperatively, 38% at 6 months, 55% at 12 months, and 93% at 36 months postoperatively. Tympanograms improved to type A in 50% at 6 months, 59% at 12 months, and 85% at 36 months. Mean scores of mucosal inflammation declined from 3.2 (±0.6) preoperatively to 2.5 (±0.7) at 6 months and 1.7 (±0.6) at 36 months postoperatively. BDET had lower risk of failure versus TT insertion (adjusted hazard ratio [HR] 0.26; 95% confidence interval [CI]: 0.10, 0.70; p = 0.007). Probability of being failure free at 2 years was 87% (95% CI: 70, 94%) after BDET and 56% (95% CI: 40, 70%) after TT insertions. BDET is a safe and possibly effective procedure in selected pediatric patients with chronic ETD.

Tensor Veli Palatinopexy as a Novel Treatment for Eustachian Tube Dysfunction: A Cadaveric Feasibility Study.

To demonstrate the feasibility of a novel procedure whereby a suture is placed transorally in the tensor veli palatini muscle to tighten it, thereby dilating the cartilaginous portion of the eustachian tube (ET). The study design was a prospective cadaveric experiment to examine the feasibility of a novel treatment for ET dysfunction. Academic medical center in a research-oriented operating room with intraoperative computed tomography (CT) capabilities. Seven fresh-frozen cadaver heads were obtained, each of which was thawed for 36 hours prior to use. The preprocedural volumes of the cartilaginous ET were measured by filling the ET with an iodine-containing radiocontrast agent via the nasopharynx and then obtaining CT images. Submucosal flaps in the soft palate were raised, and sutures were placed in the tensor veli palatini bilaterally to increase tension. After completion of the procedure, contrast placement and CT imaging were repeated. Three-dimensional models of the ETs were created, and the volumes were measured and compared. Of the 14 ETs evaluated, 13 showed an increase in postprocedure volume. On average, postprocedure volumes showed a 57% increase from preprocedure volumes (mean relative change, 57.1%; P = .013). Placement of a tension-holding suture in the tensor veli palatini muscle can reliably dilate the cartilaginous portion of the ET. Such a procedure may be useful in the treatment of ET dysfunction.

Eustachian Tube: Computed Tomography Analysis.

Eustachian tube has a major role in ventilation, drainage, and protection of the middle ear. High resolution computed tomography magnifies the role of preoperative imaging for detailed inner and middle ear anatomical information. The aim of this study was to find an applicable way by computed tomography imaging for assessment of Eustachian tube. The goal was to provide improved understanding of the Eustachian tube measurements and the relationship with middle ear in Egyptian population. Computed tomography measurements for Eustachian tube were done including; length of the bony and cartilaginous portions, Total length of Eustachian tube, as well as the width and height of the tympanic orifice of the Eustachian tube. Also, tubotympanic and Reid plane- Eustachian tube angles were measured. Within 200 studied ears in 100 subjects, the mean total Eustachian tube length was 40.19 ± 3.05 mm, mean length of the bony Eustachian tube was 11.69 ± 1.8 mm with significant longer Eustachian tube on left side, The mean length of the cartilaginous Eustachian tube was 28.5 ± 2.95 mm with significantly longer cartilaginous and total length in male (P < 0.0001). The mean width and height of the tympanic orifice of the Eustachian tube was 5.4 ± 0.79 and 4.85 ± 0.75 mm, respectively. The mean tubotympanic angle of the Eustachian tube was 148.11 ± 2.82°. The mean Reid plane- Eustachian tube angle was 27.69 ± 2.08° with significantly wider angle in males (P < 0.022). The Eustachian tube measurements can easily be obtained on computed tomography images, and are representative for the Eustachian tube anatomy. There is importance of extending computed tomography examinations beyond the middle ear cavity and the mastoids to the Eustachian tube in order to have more data on its condition and relations with different pathological conditions. Computed tomography provides improved understanding of the Eustachian tube measurements and relationship with middle ear structures.

Practical Guide for Identification of Internal Carotid Artery During Endoscopic Nasopharyngectomy.

View Supplementary Video 1 Laryngoscope, 2020

The usefulness of Valsalva computed tomography as an assessment tool for the Eustachian tube

To determine the usefulness of 'computed tomography (CT) with Valsalva maneuver (VM)' (Valsalva CT) for localizing lesions of the eustachian tube (ET) and identifying characteristics of ET dysfunction (ETD). In this case-control study, 12, 17, and 25 patients with obstructive ETD (OETD), patulous eustachian tube (PET), and conductive hearing loss (control), respectively, underwent Valsalva CT in the supine position. The visualized length to total length ratio of the cartilaginous ET (VTRET) with and without VM were compared in the three groups. In the OETD group, obstructed areas of the ET were identified on multiplanar reconstructed images. VTRET without VM in the PET group was significantly higher than that in the control and OETD groups (p-values, 0.003 and 0.007, respectively). However, there was no significant difference between the control and OETD groups (p=0.053). VTRET with VM in the PET group was significantly higher than that in the other two groups (p<0.001), whereas that in the control group was significantly higher than that in the OETD group (p<0.001). In the OETD group, the obstructed area was clearly identified, and there were one, one, six, and eight patients in the isthmus; bony portion and isthmus; bony portion, isthmus, and cartilaginous portion; and isthmus and cartilaginous portion subgroups, respectively. Valsalva CT is particularly valuable as a visualization assessment tool for identifying obstructed areas in the OETD. It may help future research of disease-specific mechanical characteristics of the ET on controlling pressure variables.

The endoscopic endonasal eustachian tube anterolateral mobilization strategy: minimizing the cost of the extreme-medial approach.

The ventral jugular foramen and the infrapetrous region are difficult to access through conventional lateral and posterolateral approaches. Endoscopic endonasal approaches to this region are obstructed by the eustachian tube (ET). This study presents a novel strategy for mobilizing the ET while preserving its integrity. Qualitative and quantitative comparisons with previous ET management paradigms are also presented. Ten dry skulls were analyzed. Four ET management strategies were sequentially performed on a total of 6 sides of cadaveric head specimens. Four measurement groups were generated: in group A, the ET was intact and not mobilized; in group B, the ET was mobilized inferolaterally; in group C, the ET underwent anterolateral mobilization; and in group D, the ET was resected. ET range of mobilization, surgical exposure area, and surgical freedom were measured and compared among the groups. Wide exposure of the infrapetrous region and jugular foramen was achieved by removing the pterygoid process, unroofing the cartilaginous ET up to the level of the posterior aspect of the foramen ovale, and detaching the ET from the skull base and soft palate. Anterolateral mobilization of the ET facilitated significantly more retraction (a 126% increase) of the ET than inferolateral mobilization (mean ± SD: 20.8 ± 11.2 mm vs 9.2 ± 3.6 mm [p = 0.02]). Compared with group A, groups C and D had enhanced surgical exposure (142.5% [1176.9 ± 935.7 mm2] and 155.9% [1242.0 ± 1096.2 mm2], respectively, vs 485.4 ± 377.6 mm2 for group A [both p = 0.02]). Furthermore, group C had a significantly larger surgical exposure area than group B (p = 0.02). No statistically significant difference was found between the area of exposure obtained by ET removal and anterolateral mobilization. Anterolateral mobilization of the ET resulted in a 39.5% increase in surgical freedom toward the exocranial jugular foramen compared with that obtained through inferolateral mobilization of the ET (67.2° ± 20.5° vs 48.1° ± 6.7° [p = 0.047]) and a 65.4% increase compared with that afforded by an intact ET position (67.2° ± 20.5° vs 40.6° ± 14.3° [p = 0.03]). Anterolateral mobilization of the ET provides excellent access to the ventral jugular foramen and infrapetrous region. The surgical exposure obtained is superior to that achieved with other ET management strategies and is comparable to that obtained by ET resection.

Endoscopic Nasopharyngectomy Combined with a Nerve-sparing Transpterygoid Approach.

Surgical management of nasopharyngeal tumors has evolved in the endoscopic era. Lateral exposure remains difficult especially near the petrous internal carotid artery and bony Eustachian tube (ET). Our study examines the need to sacrifice the vidian and greater palatine nerves in order to successfully perform en bloc endoscopic nasopharyngectomy. Four cadaveric specimens (eight sides) were dissected bilaterally using a binarial, extended, endoscopic endonasal approach (EEA). Nasopharyngectomy was completed including an extended transptyergoid approach for resection of the cartilaginous ET at its junction with the bony ET. Dissection was attempted without sacrifice of the vidian or palatine nerves. Successful en bloc nasopharyngectomy combined with a nerve-sparing transpterygoid approach was achieved in all specimens with successful preservation of the palatine and vidian nerves. The approach provided exposure of foramen lacerum, the petrous carotid, foramen spinosum, and foramen ovale as well as all segments of the cartilaginous Eustachian tube, Meckel's cave and the parapharyngeal carotid. There was no inadvertent exposure or injury of the internal carotid artery. Endoscopic nasopharyngectomy combined with a nerve-sparing transpterygoid approach allows for en bloc resection of the cartilaginous Eustachian tube and nasopharyngeal contents with broad skull base exposure and preservation of the internal carotid artery, vidian and palatine nerves. VI Laryngoscope, 130:2343-2348, 2020.