Anatomical variations of interest for posterior nasal nerve cryotherapy in the treatment of chronic rhinitis: A radioanatomic study

KEY POINTS

An unfavorable insertion of the middle turbinate for cryotherapy was present in 74.2% of cases. Placing cryoprobe 15-30 mm above the nasal floor targets the nerves in 95.8% of cases. Centering the cryoprobe 38 mm behind the inferior turbinate axilla targets the nerves in 94.6% of cases.

Anatomic Relationship Between the Head of the Middle Turbinate and First Olfactory Filum: A Radiographic Assessment

BACKGROUND

The endoscopic modified Lothrop procedure (EMLP) has become a frequently utilized procedure in rhinologic surgery. One of the most serious complications of the procedure is cerebrospinal fluid leak, which may occur due to lack of recognition of the anterior skull base in the region of the first olfactory filum (FOF), or direct injury to the FOF itself.

OBJECTIVES

To evaluate the position of the head of the middle turbinate (MT) relative to the FOF, which is an important landmark in the EMLP.

METHODS

A series of previously obtained patient computed tomography scans of the sinus were reviewed. A reproducible process was implemented to obtain the measurements. First, the FOF was identified on an axial series. Using a localization feature of the radiographic software, this anteroposterior (AP) position could be visualized in a coronal plane. Subsequently, the MT was viewed in a sagittal plane, where a measurement between the head of the MT and the AP position of the FOF could be performed.

RESULTS

The AP distance between the head of the MT and the FOF was measured in 92 patients. The head of the MT was either at or anterior to the FOF in all measured subjects. The mean anterior distance of the head of the MT to FOF was 3.6 mm (±2.4 mm) on the right, and 3.8 mm (±2.2 mm) on the left. The range in AP distance was 0 to 12 mm. There was no significant difference in AP distance between the head of the MT and FOF based on gender (P = .413) or diagnosis (P = .254).

CONCLUSIONS

In our study, the head of the MT was reliably at or anterior to the FOF in all subjects, suggesting its utility as a fixed landmark in endoscopic sinus surgery, particularly in the EMLP.

LEVEL OF EVIDENCE

N/A.

A Consistent Endoscopic Landmark to Identify the Anterior Ethmoidal Artery

OBJECTIVE

The anterior ethmoidal artery (AEA) is an important structure to identify during endoscopic sinus surgery. Although identification on imaging is easily taught, a consistent endoscopic landmark for the AEA, independent of anatomic ethmoid cell variation, is lacking, leaving many surgeons unclear about the exact location without dependence on navigation. Here, we describe a consistent endoscopic landmark, regardless of anatomical ethmoid variation.

METHODS

We prospectively enrolled adult patients undergoing endoscopic surgery involving frontal and ethmoid sinuses in this observational study. The AEA landmark was defined simply as the septation or ridge one step back along the ethmoid skull base from the posterior table of the frontal sinus. The gold standard to calculate the sensitivity of our endoscopic landmark was an image-navigation system, registered to within 1.5 mm accuracy, locating the AEA within three planes. Both endoscopic and computerized tomography (CT) images of the pointer at the landmark were taken simultaneously. The concordance of endoscopic to navigation images was independently assessed by three blinded rhinologists.

RESULTS

Forty patients were included in our study with 73 sides analyzed. Diagnoses included chronic rhinosinusitis without polyps (52.5%), with polyps (22.5%), recurrent acute sinusitis (15%), sinonasal tumors (7.5%), and odontogenic sinusitis (2.5%). The AEA was accurately identified using our endoscopic landmark in 97.3% of the cases (71/73). Of the two cases in which the AEA was not found within the landmark, the artery was located ≤1 mm posteriorly.

CONCLUSION

We describe a consistent endoscopic landmark to identify the AEA, conserved across various clinical diagnoses and anatomic variations in sinus structure.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:1096-1099, 2024.

Impact of long-term nasal airflow deprivation on sinonasal structures and chronic rhinosinusitis in total laryngectomy patients

Objective

Total laryngectomy (TL) patients are good models in which to evaluate the effects of nasal airflow cessation on the sinonasal tract. Here, we evaluated changes in sinonasal structures and association with sinus opacification in the computed tomography (CT) images 3 years post-TL.

Methods

Patients who underwent TL from 2005 to 2017 in a teaching academic center were reviewed retrospectively. Patients with a final follow-up CT taken less than 3 years after TL, tracheoesophageal puncture, inadequate CT image, or history of sinonasal surgery were excluded. The control group included patients who underwent a partial laryngectomy or hypopharyngectomy without requiring a tracheotomy for more than a month. Altogether, 45 TL patients and 38 controls were selected. The volume of all four paranasal sinuses, inferior turbinate soft tissue volume (ITSTV), maxillary sinus natural ostium (MSNO) mucosal width, and Lund-Mackay scores (LMS) were measured on preoperative and postoperative CT scans.

Results

The mean duration between surgery and the final CT scan was 6.3 ± 2.4 and 5.5 ± 2.3 years for the TL and control groups, respectively. Neither group showed significant changes in the four paranasal sinuses' volume or MSNO mucosa width. The ITSTV decreased significantly, from 4.6 ± 1.3 to 2.8 ± 1.1 mL (p < .001), in the TL group, regardless of the presence of nasal septal deviation, showing ITSTV reduction on both concave and convex sides. By contrast, the control group showed no significant changes in ITSTV. Postoperative LMS changes in both groups were insignificant. The number of patients with LMS aggravation or alleviation was the same in both groups, regardless of preoperative sinus opacification.

Conclusions

Paranasal sinus structures and sinus opacification are not affected significantly by nasal airflow cessation; however, the inferior turbinate mucosa is affected by long-term discontinuation of nasal airflow.

Level of Evidence

4 (case-control study).

Biological sex as a modulator in rhinologic anatomy, physiology, and pathology: A scoping review

BACKGROUND

Biological sex is increasingly recognized as a critical variable in health care. The authors reviewed the current literature regarding sex-based differences in rhinology to summarize the data and identify critical knowledge gaps.

METHODS

A scoping review was conducted. Publications reporting sex-based differences in anatomy, physiology, and pathology focusing on disease prevalence, disease burden, and outcomes in rhinology were identified.

RESULTS

Seventy-five relevant manuscripts were identified. While paranasal sinuses are of similar size at birth, they become larger in males leading to differences in ostium location. Females outperform males in olfactory identification but only in the 18- to 50-year age group. Estrogen and progesterone administration can impact muscarinic and α1 -adrenergic nasal mucosa receptor density. Chronic rhinosinusitis (CRS) and CRS without nasal polyps are more prevalent in females while CRS with nasal polyps is more prevalent in males. CRS symptom burden is higher in females before and after endoscopic sinus surgery; however, no difference in endoscopic sinus surgery utilization was found based on sex. Allergic rhinitis is more common in males before puberty and in females after puberty. Epistaxis is more prevalent in males and postmenopausal females compared with premenopausal females, perhaps from differences in sex-hormonal and hypertension status. In nasopharyngeal carcinoma, the incidence of sinus abnormalities was higher in males than females.

CONCLUSIONS

Although many sex-based differences exist in rhinology, further research is necessary to offer evidence-based treatment guidelines. Gonadal hormones should be studied as a therapeutic in rhinologic pathology as baseline physiologic differences exist such as those found in nasal mucosa receptor density.

Volumetric Changes of the Paranasal Sinuses with Age: A Systematic Review

BACKGROUND

There are four pairs of paranasal sinuses: maxillary, ethmoidal, frontal, and sphenoidal. It is common to see changes in size and shape throughout life, so understanding the effect of age on sinus volume can help in radiographic studies and in planning dental and surgical procedures in the sinus-nasal region. The aim of the present systematic review was to perform a qualitative synthesis of available studies which assess the volumetric characteristics of the sinuses and their changes according to age.

MATERIALS AND METHODS

The present review followed PRISMA 2020 guidelines. A systematic advanced electronic search was performed in five databases (Medline (via PubMed), Scopus, Embase, Cochrane, and Lilacs) in June-July 2022. Studies that assessed the volumetric changes of paranasal sinuses with age were eligible for inclusion. A qualitative synthesis of the methodology and results of the included studies was performed. Quality assessment was performed using the NIH quality assessment tool.

RESULTS

A total of 38 studies were included in the qualitative synthesis. Most authors who studied the maxillary and ethmoidal sinuses concluded that it begins its development from birth until the maximum peak of growth, from which it begins to decrease in volume with age. Results regarding the volumetric changes of the frontal and sphenoidal sinuses are mixed.

CONCLUSIONS

Based on the results of the studies included in the present review, it can be concluded that the volume of the maxillary and ethmoidal sinus appears to decrease with age. Conclusions on the volumetric changes of the sphenoidal and frontal sinuses require further evidence.

Development of an optimized preoperative computed tomography imaging checklist for endoscopic sinus surgery utilizing a systematic review of the literature and the modified Delphi method

BACKGROUND

Critical review of computed tomography (CT) imaging is essential in preoperative planning for endoscopic sinus surgery. In this study, we used a systematic review and a modified Delphi method to develop a comprehensive checklist that facilitates preoperative review of sinus CT imaging.

METHODS

We performed a systematic review of PubMed, Embase, CINAHL, Cochrane, and Web of Science databases to identify existing checklists developed to evaluate sinus CT imaging. An inclusive list of items from these checklists was compiled and a modified Delphi methodology was used to assign ranked priority. The Delphi process involved 14 rhinologists and had three phases: an initial survey with Likert priority (scale of 1-9) and two rounds of live discussions followed by survey to confirm consensus.

RESULTS

Ninety-seven possible checklist items were identified from a systematic review and panelist input. On initial survey, 63 items reached a consensus score of 7+, and 13 items had near consensus scores between 6 and 7; two of these 13 borderline items were retained after subsequent panelist discussion. The resulting items were consolidated into an 11-item disease checklist and a 24-item anatomical checklist; the anatomical checklist was further divided into six subsections: nasal cavity, maxillary, ethmoid, sphenoid, frontal, skull base, and orbit. Additionally, panelists identified six core aspects of patient history to consider prior to surgery.

CONCLUSIONS

After establishing content validity through a systematic literature review and a modified Delphi method, we developed a comprehensive checklist for preoperative sinus CT imaging review; implementation and evaluation of validity among trainees will suggest overall utility.

Three-Dimensional Volumetric Analysis of Frontal Ethmoidal Cells and Evaluation of Influential Factors: A Helical Computed Tomography Study

In the present study, we aimed to assess frontal ethmoidal cells by using segmentation 3D software to establish a possible correlation between volume variation and both gender and age, as well as a relationship with Keros classification. Helical computed tomography images were obtained from 71 patients for analysis, in which the agger nasi cell, supra agger cell, supra agger frontal cell, supra bulla frontal cell, supraorbital ethmoidal cell, supra bulla cell, and frontal septal cell were identified and segmented to obtain their volume. Significant differences in volume were found for age and gender regarding agger nasi cells (p-value = 0.017), supra agger cells (p-value < 0.001), and frontal septal cells (p-value = 0.049). In the frontal septal cells, an increase of one year in age reduced the volume by 0.309, on average. According to Keros classification, the mean volumes were 10.07 and 25.64, respectively, for types II and III, both being greater than that of type I. Extracting volumetric data by using segmentation software in agger nasi cells, supra agger cells, and frontal septal cells may be useful for obtaining additional information related to age, in addition to possibly contributing to elucidating the anatomical variations in the region and an identification forensic tool.

Radiological Assessment of High Anterior Septal Deviation and Its Impact on Sinus Access

OBJECTIVES/HYPOTHESIS

High anterior septal deviation (HASD) is an underreported anatomic variant that can affect the decision to perform septoplasty for access during sinus surgery and ease of postoperative debridement. This study aims to 1) describe an objective method of assessing HASD, and 2) explore its prevalence and implications for performing septoplasty.

STUDY DESIGN

Retrospective cross-sectional study.

METHODS

Computed tomography scans from 2014 to 2020 were retrospectively reviewed. Two independent observers measured the following with respect to midline: distance to septum (SDD), distance to lateral nasal wall (LNW), and septal deviation angle (SDA).

RESULTS

A total of 147 patients were included, with excellent interrater reliability across 99 patients (0.8-0.9). Mean measurements across all patients were SDD (2.77 mm ± 1.34), SDD/LNW (0.26 ± 0.12), and SDA (8.9° ± 4.0). Of 102 patients who underwent sinus surgery, 47 received septoplasty. Compared to the non-septoplasty cohort, the septoplasty cohort had a greater mean SDD (3.61 mm ± 1.48 vs. 2.27 mm ± 0.95; d = 1.10 [95% CI 0.67-1.51]), SDD/LNW (0.34 ± 0.13 vs. 0.21 ± 0.09; d = 1.18 [95% CI 0.76-1.60]), and SDA (11.1° ± 4.3 vs. 7.3° ± 3.4; d = 1.00 [95% CI 0.58-1.40]). Receiver operating characteristic cutoffs were SDD ≥2.43 mm, SDD/LNW ≥0.25, and SDA ≥7.6°, corresponding to a 49%-58% prevalence of HASD.

CONCLUSION

HASD is relatively common and the methods described herein can reliably assess its dimensions. Measurements of SDD, SDD/LNW, and SDA exceeding cutoffs determined by this study may represent clinically significant deflections prompting consideration of septoplasty. These methods may aid in preoperative planning.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Endoscopic Endonasal Prelacrimal Approach: Radiological Considerations, Morbidity, and Outcomes

OBJECTIVE/HYPOTHESIS

This study describes a multicentric experience with the use of prelacrimal approach (PLA), focusing on preoperative radiological parameters potentially associated with surgical outcomes and postoperative morbidity.

STUDY DESIGN

Retrospective case-series.

METHODS

A retrospective review of patients undergoing PLA in three European referral centers was performed. The post-operative morbidity was analyzed in relation to two radiological parameters: width of prelacrimal recess (WPR) and internal angle of pyriform notch (APN).

RESULTS

The study included 28 patients affected by Schneiderian papilloma (20 cases), inflammatory disease (6 cases), schwannoma (1 case), and osteoma (1 case). The most reported sequela was paresthesia of ipsilateral anterior superior alveolar process (25% of the cases). An association between post-operative morbidity and APN was observed (P = .047).

CONCLUSIONS

Preoperative radiological evaluation of WPR is crucial in understanding the feasibility of the approach, while APN measurement may predict postoperative morbidity, which is paramount in the patients' counseling.

LEVEL OF EVIDENCE

4 case-series Laryngoscope, 131:1715-1721, 2021.

Development of a self-directed sinonasal surgical anatomy video curriculum: Phase 1 validation

BACKGROUND

Sinusitis is a common outpatient diagnosis made by physicians and is a reason for referral to otolaryngologists. A foundation in basic sinonasal anatomy is critical in understanding sinus pathophysiology and avoiding complications. Our objective in this study was to develop and to validate a self-directed surgical anatomy video for medical students.

METHODS

Two multimedia videos were developed highlighting sinonasal anatomy. In Video 1 we included audio narration and radiologic imaging. Video 2 incorporated highlighted images from a sinus surgery video. An assessment was developed to test sinonasal anatomy landmarks, spatial recognition of structures, and their clinical relevance. An expert panel of rhinologists scored face and content validity of the curriculum videos and assessment. Factor analysis was used to separate questions into face and content validity domains, and a one-sample t test was performed.

RESULTS

The panel scored face validity (Videos 1 and 2: 4.4/5) and content validity (Video 1: 4.5/5, 0.83; Video 2: 4.3/5, 0.75) significantly higher than a neutral response. There were no statistical differences for face or content validity between videos. The assessment was rated suitable (29%) or very suitable (57%) for testing basic sinonasal surgical anatomy, and the majority (71%) of respondents agreed (14%) or strongly agreed (57%) that the assessment thoroughly covered the sinus anatomy content with which medical students should be familiar.

CONCLUSION

We have developed two videos and an assessment that highlight and test sinonasal anatomy. Future studies will aim to identify whether the use of a self-directed video curriculum improves sinonasal anatomy awareness and whether incorporation of surgical endoscopic videos augments training.

The Risks of Complications During Endoscopic Sinus Surgery in Cystic Fibrosis Patients: An Anatomical and Endoscopic Study

OBJECTIVE/HYPOTHESIS

An increasing proportion of adult cystic fibrosis (CF) patients is being referred to endoscopic sinus surgery (ESS) in order to relieve the symptoms of chronic rhinosinusitis (CRS). Given that CFTR mutations profoundly alter sinonasal development, we want to explore the relationship between their peculiar surgical anatomy and the risk of postoperative complications.

STUDY DESIGN

Retrospective case-control study.

METHODS

Paranasal sinuses CT scans of 103 CF adult patients with CRS were compared to those belonging to a cohort of 100 non-CF adult patients to explore their anatomical differences. Secondly, CF and non-CF patients who received primary/revision ESS were analyzed in order to assess their preoperative CT scan in terms of surgically relevant variants, and according to the CLOSE checklist. Surgical outcomes were statistically compared in order to explore the differences between groups.

RESULTS

CF group presented more frequently with smaller and less pneumatized paranasal sinuses and a higher Lund-Mckay score compared with controls. No anatomical differences emerged in terms of genotype stratification. Non-CF CRS patients undergoing ESS showed a significantly deeper olfactory fossa and a more frequent supraorbital pneumatization compared to CF patients (P < .001 and P = .031, respectively). Whereas this latter group underwent more often aggressive surgical procedures (P = .001), no difference in terms of postoperative adverse events was found (P = .620).

CONCLUSIONS

Despite receiving more often aggressive ESS procedures, adult CF patients do not show an increased risk of postoperative complication and this may be linked to a different proportion of anatomical and surgically-relevant variants.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E2481-E2489, 2021.

High Variability of Postsurgical Anatomy Supports the Need for Individualized Drug-Eluting Implants to Treat Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is a common disease in the general population that is increasing in incidence and prevalence, severely affecting patients’ quality of life. Medical treatment for CRS includes self-management techniques, topical and oral medical treatments, and functional endoscopic sinus surgery (FESS). FESS is a standard procedure to restore sinus ventilation and drainage by physically enlarging the inflamed sinus passageways. Nasal drug-releasing stents are implanted to keep the surgically expanded aperture to the sinus frontalis open. The outcome of such an intervention is highly variable. We defined the anatomical structures which should be removed, along with ‘no-go areas’ which need to be preserved during FESS. Based on these definitions, we used cone beam computed tomography (CBCT) images to measure the dimensions of the frontal neo-ostium in 22 patients. We demonstrate anatomical variability in the volume and diameter of the frontal sinus recess after surgery. This variability could be the cause of therapy failure of drug-eluting implants after FESS in some patients. Implants individually made to fit a given patient’s postsurgical anatomy may improve the therapeutic outcome.

Chronic rhinosinusitis: assessment of changes in nociceptive neurons

BACKGROUND

Pain is a major symptom of chronic rhinosinusitis (CRS). It is mainly associated with CRS without nasal polyps (CRSsNP) and has a major impact in the decision to move on to surgery. Patients with CRS with nasal polyps (CRSwNP) are characterized by trigeminal hypoesthesia and suffer from less pain. The aim of this study was to investigate whether CRS induces alterations in the peripheral nociceptive neurons, mainly focusing on quantitative changes.

METHODS

Sinus mucosa and inferior turbinate (IT) samples were obtained from patients with CRS, and IT tissue of healthy patients served as controls. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was performed for neuronal markers including CNTNAP2, FAM19A1, GFRA2, NEFH, NTRK1, PLXNC1, RET, SCN10A, SCN11A, TRPV1, and PGP 9.5; enzyme-linked immunosorbent assay (ELISA) was performed for KCNK18, SCN10A, MRGPRD, and MAP2. For PGP 9.5, immunohistochemistry was additionally used to analyze tissue slides.

RESULTS

We included 35 patients with CRSsNP, 47 patients with CRSwNP, and 18 control patients. No differences in expression of the neuronal markers were observed between CRSsNP, CRSwNP, and controls. SCN10A was the only marker exclusively expressed on nociceptive neurons in sinus tissue. No histological difference in nerve fibers was observed between sinus mucosa of both phenotypes.

CONCLUSION

Our results indicate that the nociceptive nerve density in CRSwNP is not lower than in CRSsNP, as was assumed previously. The nociceptive neurons in sinonasal mucosa cannot be classified into subtypes due to the lack of specificity of the respective marker genes. Our findings question the generally accepted claim that nasal polyp tissue does not contain any nerves.

Location of the Sphenoid Sinus Ostium in Relation to Adjacent Anatomical Landmarks

PURPOSE

The variability of sphenoid pneumatization and its relationship with the surrounding structures has been suggested. The aim of this study was to examine the effect of the surrounding bony structures on the position of the sphenoid ostium (SO).

METHODS

A prospective radiological review of computed tomography images of paranasal sinuses of 150 patients (300 sides) was conducted. Parameters investigated included the presence of Onodi cells, sphenoid rostrum pneumatization, and the type of sphenoid pneumatization on the coronal and sagittal planes. Their effect was studied on the vertical and horizontal plane using lines of measurement 1 through 5.

RESULTS

The most common location of the SO on the horizontal plane was found to be in the middle third and was significantly affected by the rostrum pneumatization (P value <.001) and sphenoid pneumatization on the coronal plane (P value = .018). The location of the SO on the vertical plane was most commonly in the middle third. It was significantly affected by Onodi cell pneumatization (P value = .021) as well as the sphenoid height (P value <.001).

CONCLUSIONS

Pneumatization of the sphenoid sinus and adjacent bony structures can affect the location of the SO. Presence of rostrum pneumatization and lateral sphenoid pneumatization shift the SO laterally. Presence of Onodi cell and low sphenoid roof shift the SO inferiorly. These variations need to be studied carefully before surgery in order to avoid operative complications.

Virtual coach: the next tool in functional endoscopic sinus surgery education

BACKGOUND

Functional endoscopic sinus surgery (FESS) can be challenging as novices become accustomed to handling endoscopes and instruments while navigating complex sinonasal anatomy. Experts demonstrate fluid and efficient motions when addressing pathology. The training process from novice to expert relies on hands-on experience in cadaveric laboratories and preceptorship models that require significant time and expense. This study aims to validate the use of a virtual coach to guide users step-by-step through a basic FESS.

METHODS

Seventeen surgeons were grouped into novice (n = 10) and expert (n = 7) based on self-reported levels of surgical experience. Users were trained using the maxillary antrostomy module in the Neurorhinological Surgery (NRS) simulator combining the physical craniofacial model with virtual reality (VR)-tracked surgical instruments in the VR operating room. The virtual coach guided the user using surgical videos, auditory, and visual cues. The coach recorded data for each subject including the number of times borders of the nasal cavity were encountered and time to completion. Users graded the usefulness of the virtual coach on a Likert questionnaire.

RESULTS

Face validity of our NRS simulator was replicated by user questionnaires, and construct validity replicated by differentiation between novice and expert level surgeons (p < 0.01). Novices contacted a significantly higher number of anatomic borders (n = 17) and had a longer operative time (t = 370 seconds). All users reported high scores on the benefit and usefulness of the virtual coach.

CONCLUSION

The virtual coach provides a useful tool to enhance FESS education by providing objective real-time data in a novel mixed-reality surgical environment.

Risk factors in lateral window sinus elevation surgery

Maxillary sinus augmentation is the most predictable of the pre-prosthetic surgical procedures. There are, however, known and well-documented complications that can and do occur. The most common are the intraoperative complications of sinus membrane perforation and bleeding, and the postoperative complications of sinus graft infections, sinus infections, and sinusitis. The majority of these complications can be prevented, or their incidence greatly reduced, through a thorough understanding of maxillary sinus anatomy, the multifaceted etiologies of these conditions, and the steps that can be taken to avoid them. This volume of Periodontology 2000 will discuss both the preoperative and intraoperative procedures that will prevent these untoward outcomes and the necessary treatment modalities that will limit their adverse effects.

Evaluation of three-dimensional contraction of the volume of grafts after staged augmentation of the sinus floor, and an analysis of influential factors

Our aim was to evaluate the volume by which grafts contract after augmentation of the sinuses by three-dimensional analysis on cone-beam computed tomographs (CT), and to investigate the factors that influence the outcomes. The sinus floor was augmented with deproteinised bovine bone mineral in 58 patients with 123 edentulous sites related to 67 sinuses. The outcomes of augmentation were analysed by both linear and volumetric measurements on cone-beam CT images taken immediately after operation and six months later. Mathematical models were established to investigate the influence of anatomical characteristics of the sinuses and patient-related factors on contraction of the volume of the grafts. The mean reduction in the height of the grafts on site-based analysis was 17.8% after six months, and the contraction in volume on sinus-based analysis was 22.7 %. Of the edentulous sites 20/123 (16%) could not have implants 10 mm long inserted at the second stage operation because of insufficient bony height. Linear regression indicated that the type of edentulism (single or multiple teeth lost) was significantly associated with contraction in the volume of the grafts (p=0.006). Mixed model regression showed that the reduction in the height of the grafts was significantly influenced by the width of the sinus floor and the angle between the lateral and the medial wall of sinus (p=0.001, p=0.000). The reduction in height of the grafts and contraction in volume on linear and volumetric measurements six months after augmentation were roughly 18% and 22%, respectively. A wide sinus, large lateromedial angle, and loss of multiple teeth under the same sinus strongly predict that large amount of grafts will resorb. The anatomy of the sinus and patients' characteristics should be taken into consideration before treatment.

Image quality and dose reduction in sinus computed tomography using iterative reconstruction: a cadaver study

Background

Concerns about radiation dose in computed tomography (CT) imaging have renewed interest in iterative reconstruction (IR), a technique which has the potential to produce images with less noise at lower radiation doses than traditional filtered back projection (FBP). This study aimed to assess whether application of IR could provide comparable quality sinus CT images to FBP at lower kilovolt (kV) and milliamp (mA) settings, and to establish optimal scan settings for sinus imaging.

Methodology/Principal

30 sinus CT scans were performed on 5 cadaver heads at two kV setting and three mA settings. Each scan was reconstructed using FBP and 3 IR settings, yielding a total of 120 images series. Each image set was blinded and randomly reviewed by 3 rhinologists and 2 neuroradiologists. Using a 5-point Likert scale, 16 anatomical landmarks, were graded with respect to image quality. Data were assessed with respect to dose and IR settings using statistical analysis.

Results

Higher kV and mAs settings produced significantly higher quality images for structure identification across all 16 landmarks; however, the suitability for surgery did not increase in a linear fashion and plateaued by a total radiation dose of 0.1201 mSv. IR algorithm did not provide a benefit in the overall score of scans at a fixed kV and mAs.

Conclusions

Identification of structures in sinus CT imaging significantly correlate with the kV and mA and overall dose of radiation; however, IR did not provide additional benefit in the image quality.

Teaching Residents Frontal Sinus Anatomy Using a Novel 3-Dimensional Conceptualization Planning Software-Based Module

BACKGROUND

The Frontal Sinus Masterclass (FSMC) is an effective method for teaching frontal sinus anatomy. A third party developed new software using the same 3-dimensional building block concept. The authors sought to determine whether the use of the software for the educational module yielded similar results to the original FSMC, which used wooden blocks.

METHODS

The study was performed at a sinus course for residents. A precourse test assessed the ability to decipher frontal sinus anatomy prior to the course. Computed tomography (CT) scans of the sinuses were evaluated in triplanar view, and participants attempted to reconstruct the anatomy using the new software. Subsequently, the course instructor explained the anatomy and showed a short corresponding surgical video of the frontal sinusotomy. Cases progressed in anatomical difficulty and inflammatory load. A postcourse test determined knowledge after the course.

RESULTS

In sum, 50 residents completed the pre- and postcourse tests. Overall scores increased from 60.5% to 65.2% ( P = .004). Subanalysis also demonstrated improved ability to locate the frontal drainage pathway from 32.5% to 46% ( P = .011) and label the frontal recess cell structures from 64% to 67.6% ( P = .045).

CONCLUSION

There is minimal literature on proven methods for teaching frontal sinus anatomy. Objectively, participants of the modified FSMC simulation training using new software improved their ability to recognize cells of the frontal recess on CT scans. They especially exhibited better localization of the frontal sinus drainage pathway. Subjectively, participants reported benefit from the course and felt they would be better surgeons.

International assessment of inter- and intrarater reliability of the International Frontal Sinus Anatomy Classification system

BACKGROUND

Inconsistencies in the nomenclature of structures of the frontal sinus have impeded the development of a validated "reference standard" classification system that surgeons can reliably agree upon. The International Frontal Sinus Anatomy Classification (IFAC) system was developed as a consensus document, based on expert opinion, attempting to address this issue. The purposes of this study are to: establish the reliability of the IFAC as a tool for classifying cells in the frontal recess among an international group of rhinologists; and improve communication and teaching of frontal endoscopic sinus surgery (ESS).

METHODS

Forty-two computed tomography (CT) scans, each with a marked frontal cell, were reviewed by 15 international fellowship-trained rhinologists. Each marked cell was classified into 1 of 7 categories described in the IFAC, on 2 occasions separated by 2 weeks. Inter- and intrarater reliability were evaluated using Light's kappa (κ), the interclass correlation coefficient (ICC), and simple proportion of agreement.

RESULTS

Interrater reliability showed pairwise κ values ranging from 0.7248 to 1.0, with a mean of 0.9162 (SD, 0.0537). The ICC was 0.98. Intrarater reliability showed κ values ranging from 0.8613 to 1.0, with a mean of 0.9407 (SD, 0.0376). The within-rater ICC was 0.98.

CONCLUSION

Among a diverse sample of rhinologists (raters), there was substantial to almost perfect agreement between raters, and among individual raters at different timepoints. The IFAC is a reliable tool for classification of cells in the frontal sinus. Further outcome studies are still needed to determine the validity of the IFAC.

Lateral frontoethmoidal cell obstructing frontal sinus drainage pathway - report of six cases

The European Anatomical Position Paper on the Anatomical Terminology of the Internal Nose and Paranasal Sinuses distinguishes anterior, posterior, medial and lateral frontoethmoidal cells. The lateral cells have not been characterized yet. Other classifications (Lee and Kuhn, International Frontal Sinus Anatomy Classification) neglect them. The aim of this study is to describe lateral frontoethmoidal cells in rhinosinusitis patients.

METHOD

Analysis of medical records and computed tomography (CT) examinations using multiplanar reconstruction with adjustable planes. The lateral cell extending between the frontal beak and the skull base pushing the frontal sinus drainage pathway medially/anteromedially was identified in 6 patients. These cells could not be classified as anterior, posterior or medial according to existing classifications. Four patients were operated on previously due to sinonasal symptoms. The lateral frontoethmoidal cell is an underestimated anatomical variation that may contribute to the persistence of inflammatory disease and can be easily overlooked preoperatively.

Anatomy of the posterior and middle ethmoidal arteries via computed tomography

OBJECTIVE

The aim of this study is to investigate the anatomy of the posterior and middle ethmoidal arteries from the viewpoint of an endoscopic sinus surgeon.

METHODS

Based on 100 computed tomography images, the anatomical position of the posterior ethmoidal artery in relation to the posterior ethmoid cells was classified into five types. The presence of the posterior and middle ethmoidal arteries, their distance from the skull base, and their length exposed in the ethmoid cells were measured. The association of patients' age and sex, presence of the middle ethmoidal artery, and anatomical type of the posterior ethmoidal artery with the posterior ethmoidal artery distance from the ethmoid roof was analyzed.

RESULTS

The posterior ethmoidal artery's position, relative to the ethmoid cell walls, was most often near the first wall, anterior to the optic canal (92.5%). The posterior ethmoidal artery's distance from the skull base ranged from 0 to 6.4 mm (mean: 1.2 mm). Older age, longer length of the posterior ethmoidal artery exposed in the ethmoid cells, and absence of the middle ethmoidal artery were positively associated with a longer posterior ethmoidal artery distance from the skull base.

CONCLUSION

Attention should be paid to the posterior and middle ethmoidal arteries.

Dimensions of the medial wall of the prelacrimal recess

BACKGROUND

Addressing anterior maxillary sinus pathology endoscopically that is inaccessible with an endoscopic modified medial maxillectomy requires either a prelacrimal approach (PLA) or an endoscopic Denker's approach (EDA). The PLA involves removing the medial wall of the prelacrimal recess (PLR), which is the bone between the pyriform aperture (PA) and nasolacrimal duct (NLD), from nasal floor to orbital floor. The PLA preserves the inferior turbinate and NLD, whereas both are sacrificed during an EDA. The purpose of this computed tomography (CT)-based study was to determine the anteroposterior and superoinferior dimensions of the medial wall of the PLR.

METHODS

One hundred thirty-one triplanar sinus CT scans of patients with various rhinologic diseases, but with intact bony PLR walls, were reviewed to assess dimensions of the medial wall of the PLR. The anteroposterior distances from the PA to the inferior-most, middle, and superior-most aspects of the NLD were measured. The height from the nasal floor to orbital floor was also measured. Combining left and right sides, there were 262 measurements.

RESULTS

The anteroposterior distances between the PA and the NLD were as follows: inferior: mean, 8.4 mm (standard error [SE], 0.2; range, 1.9-14.2); middle: mean, 7.6 mm (SE, 0.2; range, 0-13.6); and superior: mean, 5.5 mm (SE, 2.5; range, 0-11.9). The mean height of the medial wall of the PLR was 26.5 mm (SE, 0.2; range, 18.5-39.9).

CONCLUSION

The anteroposterior and superoinferior dimensions of the medial wall of the PLR are variable, with the anteroposterior dimension being widest inferiorly. Its dimensions should be evaluated preoperatively when considering endoscopic approaches to or through the anterior maxillary sinus.

The Terracol and Ardouin developmental model of frontal sinus drainage pathway and surrounding spaces: a radiologic validation

BACKGROUND

The complexity of the frontal sinus drainage pathway (FSDP) can be challenging even for expert surgeons. Several classifications have been proposed to simplify the understanding of FSDP, whose anatomical variability can be simplified based on the knowledge of its developmental mechanisms.

METHODS

Cone-beam computed tomography studies performed at the Unit of Radiology of the University of Brescia between March and November 2012 were retrospectively analyzed. FSDP was classified as medial or lateral to the vertical portion of the uncinate process and the following anatomical variants were studied: agger nasi cell, Kuhn's cells, suprabullar cell, supraorbital ethmoid cell, suprabullar frontal cell, and frontal septal cell. The developmental model of the FSDP proposed by Terracol and Ardouin was analyzed and expected associations between the position of the drainage pathway and anatomical variants were formulated. Statistical associations between anatomical variants and the position of FSDP were calculated and compared with expected associations to validate the developmental model.

RESULTS

The anatomical variants of FSDP statistically validated the developmental model of Terracol and Ardouin.

CONCLUSION

Knowledge of the possible developmental patterns of FSDP helps the surgeon in the understanding of the complexity of the frontoethmoidal region.

Anatomic relationship of the first olfactory neuron and trochlea: cadaveric study with surgical implications

BACKGROUND

Iatrogenic injury to the trochlea is a potential complication of the Draf III or endoscopic modified Lothrop procedure; however, the location of the trochlea from within the sinus cavity has yet to be clearly characterized. We performed the first cadaveric study assessing the position of the trochlea in relation to the first olfactory neuron, a commonly identified landmark during the Draf III procedure.

METHODS

Thirteen external dissections of the trochlea were performed on 7 disarticulated cadaveric heads via an extended Lynch type incision. An endoscopic Draf III procedure was then performed on all cadavers. A burr hole was then created at the trochlear fovea. A straight vector between the trochlear attachment and the ipsilateral first olfactory neuron was then created. The vector was then viewed from within the sinuses using a 30-degree endoscope. The endoscope was maneuvered to create an upright midline view centered on the olfactory neurons. An image was subsequently captured and analyzed using ImageJ software to calculate a vector angle. The linear distance between the 2 structures was also recorded.

RESULTS

Relative to the first olfactory neuron, the trochlea was found to be 19.52 ± 4.68 mm away and at an angle of 39.42 ± 8.54 degrees in the anterolateral, superior direction along the frontal bone.

CONCLUSION

We report the first anatomical dissection characterizing the position of the trochlea relative to the ipsilateral first olfactory neuron. Intraoperative recognition of this relationship during Draf III procedures can prevent potential injury to the trochlea.

Anterior superior alveolar nerve injury after extended endoscopic medial maxillectomy: a preclinical study to predict neurological morbidity

BACKGROUND

Endoscopic medial maxillectomies (EMMs) are used to optimize exposure of the maxillary sinus and retromaxillary areas. Although in type D EMM (Sturmann-Canfield procedure) the anterior superior alveolar nerve (ASAN) is always at risk of injury, only 29% of patients complained of alveolar process and dental anesthesia. The purpose of this anatomical study is to assess the neural anastomotic network of the ASAN (ASAN-NAN) and describe different extensions of type D EMMs in a preclinical setting.

METHODS

The ASAN and its medial anastomotic branches (MABs) and lateral anastomotic branches (LABs) were evaluated by cone-beam computerized tomography (CBCT). Five different extensions of type D (D1 to D5) EMMs were identified and nerves at risk of injury in each type were assessed by CBCT. Moreover, quantification of surgical corridors was performed on cadaver heads with a neuronavigation system.

RESULTS

Fifty-seven CBCT scans were analyzed. The ASAN would be spared in 16.3% of cases with a type D1 EMM, while it would be injured in the majority of type D2 to D5 resections. At least 1 nerve of the ASAN-NAN was spared in 96.6%, 93%, 74.6%, 0%, and 65.8% of type D1 to D5 EMMs, respectively. Two cadaver heads were dissected and the incremental volume and number of maxillary subsites exposed was assessed in type D1 to D5 EMMs.

CONCLUSION

ASAN function impairment is probably compensated by LABs and MABs. If this hypothesis will be validated in a prospective study on patients, preoperative CBCT evaluation could predict neurological morbidity after type D EMM, and allow tailoring the procedure to minimize impairment of the ASAN-NAN.

Educational utility of advanced three-dimensional virtual imaging in evaluating the anatomical configuration of the frontal recess

BACKGROUND

Endoscopic sinus surgery represents a cornerstone in the professional development of otorhinolaryngology trainees. Mastery of these surgical skills requires an understanding of paranasal sinus and skull-base anatomy. The frontal sinus is associated with a wide range of variation and complex anatomical configuration, and thus represents an important challenge for all trainees performing endoscopic sinus surgery.

METHODS

Forty-five otorhinolaryngology trainees and 20 medical school students from 5 academic institutions were enrolled and randomized into 1 of 2 groups. Each subject underwent learning of frontal recess anatomy with both traditional 2-dimensional (2D) learning methods using a standard Digital Imaging and Communications in Medicine (DICOM) viewing software (RadiAnt Dicom Viewer Version 1.9.16) and 3-dimensional (3D) learning utilizing a novel preoperative virtual planning software (Scopis Building Blocks), with one half learning with the 2D method first and the other half learning with the 3D method first. Four questionnaires that included a total of 20 items were scored for subjects' self-assessment on knowledge of frontal recess and frontal sinus drainage pathway anatomy following each learned modality. A 2-sample Wilcoxon rank-sum test was used in the statistical analysis comparing the 2 groups.

RESULTS

Most trainees (89%) believed that the virtual 3D planning software significantly improved their understanding of the spatial orientation of the frontal sinus drainage pathway.

CONCLUSION

Incorporation of virtual 3D planning surgical software may help augment trainees' understanding and spatial orientation of the frontal recess and sinus anatomy. The potential increase in trainee proficiency and comprehension theoretically may translate to improved surgical skill and patient outcomes and in reduced surgical time.

Agger-bullar classification (ABC) of the frontal sinus drainage pathway: validation in a preclinical setting

BACKGROUND

The anatomy of structures surrounding the frontal sinus drainage pathway (FSDP) is extremely complex and challenging for endoscopic sinus surgeons. The anatomical nomenclature of this area reflects this complexity and lack of agreement regarding anatomical variants of this region is present in the literature. This work presents a new classification system of the air spaces surrounding the FSDP, called the agger-bullar classification (ABC), and compares it with the most widely used anatomical classification of the frontoethmoidal region, the modified Bent and Kuhn classification (MBKC).

METHODS

Fourteen human heads underwent cone beam computed tomography (CT) scan and subsequently endoscopic dissection. Anatomical data were collected by 2 radiologists in consensus, an expert surgeon, and a novice surgeon. The radiologists filled the anatomical report after examining the CT scan, and the expert surgeon had both CT scan and endoscopic dissection available. A record of the dissection was obtained to allow the novice surgeon to compile the report. Interrater agreement regarding each variable of the classification systems was estimated through Cohen's kappa value. Cohen's kappa values of variables referring to the same anatomical subunit were matched to compare ABC with MBKC.

RESULTS

For both air spaces in front and behind the FSDP, interrater agreement values of the variables of the ABC were significantly higher than the corresponding variables of the MBKC.

CONCLUSION

This preclinical study demonstrates the potential of the ABC system. Although the ABC may improve preoperative anatomical assessment of the frontoethmoidal area, validation in a clinical setting is required.

Surgical Anatomy of the Medial Wall of the Orbit in 14 Human Cadavers

Objective The aim of our study is to present the anatomical landmarks to perform an endoscopic endonasal approach to the medial wall of the orbit (EEAMO). Material and Methods We performed 14 complete nasal and orbital endoscopic dissections in 7 adult cadaveric heads. Results The EEAMO provides a surgical corridor between the medial rectus muscle superiorly and the inferior rectus muscle inferiorly .The mean distance between the ethmoidal crest and medial rectus muscle was 1.5 cm (range, 1.3-1.9 cm). The width of the medial rectus muscle was 1.2 cm (range, 1-1.5 cm). The main vascular structure in this retrobulbar space was the ophthalmic artery that crosses over the optic nerve in 86% of the cases. In its intraorbital route, the anterior ethmoidal artery and the ethmoidal nerves were situated inferior to the superior oblique muscle in all cases. The posterior ethmoidal artery was found superior to it. We could identify the inferior division of the oculomotor nerve in this surgical approach. Conclusions The EEAMO allows adequate exposure of the space between the medial rectus muscle and the inferior rectus muscle. The location of the ethmoidal crest of the palatine bone, and its relationship with the medial rectus muscle, is a useful anatomical landmark for this surgical approach.

Incidence of middle turbinate lateralization after axillary flap approach to the frontal recess

BACKGROUND

The axillary flap approach (AFA) to the frontal recess improves visualization and clearance while minimizing use of angled endoscopes. However, some argue that it destabilizes the middle turbinate (MT) and increases risk of MT lateralization (MTL). We aimed to establish rates of MTL after AFA, as well as to determine whether other surgical or disease factors affect lateralization.

METHODS

This study was a retrospective chart review. Endoscopic postoperative videos between 3 and 9 months (short-term) and greater than 9 months (long-term) were reviewed blind to surgery performed. Presence of MTL, ability to pass an endoscope into the middle meatus, and ability to evaluate the frontal recess were recorded. Surgical characteristics obtained from the chart review included: MT conchopexy, septoplasty, concha bullosa, and primary vs revision surgery. Patient characteristics included age, sex, polyposis, asthma, and smoking. Cases were excluded if the MT was absent.

RESULTS

A total of 124 patients (248 operated sides) were included in the short-term cohort. Similar numbers of primary (52.4%) and revision (47.6%) cases were performed, 42.3% had polyposis, and 38% asthmatics. Overall rate of MTL was 14.5%, with an inability to examine the frontal recess in 12.1%. Suture conchopexy of the MT through the septum did not affect lateralization. Results were statistically similar in the long-term cohort.

CONCLUSION

The AFA yielded a 14.5% and 17.4% MTL in the short-term and long-term cohorts, respectively. This rate appears consistent with reports in the literature that did not use the axillary flap. No patient or surgical factor was found to affect rates of lateralization.