Die digitale Volumentomographie in der HNO-Heilkunde

Anatomical Factors of the Anterior and Posterior Maxilla Affecting Immediate Implant Placement Based on Cone Beam Computed Tomography Analysis: A Narrative Review

BACKGROUND

The aim of this narrative review was to provide insights into the influence of the morphological characteristics of the anatomical structures of the upper jaw based on cone beam computed tomography (CBCT) analysis on the immediate implant placement in this region.

MATERIAL AND METHODS

To conduct this research, we used many electronic databases, and the resulting papers were chosen and analyzed. From the clinical point of view, the region of the anterior maxilla is specific and can be difficult for immediate implant placement.

FINDINGS

Anatomical structures in the anterior maxilla, such as the nasopalatine canal and accessory canals, may limit and influence the implant therapy outcome. In addition to the aforementioned region, immediate implant placement in the posterior maxilla may be challenging for clinicians, especially in prosthetic-driven immediate implant placement procedures. Data presented within the recently published materials summarize the investigations performed in order to achieve more reliable indicators that may make more accurate decisions for clinicians.

CONCLUSION

The possibility for immediate implant placement may be affected by the NPC shape in the anterior maxilla, while the presence of ACs may increase the incidence of immediate implant placement complications. The variations in IRS characteristics may be considered important criteria for choosing the implant properties required for successful immediate implant placement.

Cost-effective 3D scanning and printing technologies for outer ear reconstruction: current status

Current 3D scanning and printing technologies offer not only state-of-the-art developments in the field of medical imaging and bio-engineering, but also cost and time effective solutions for surgical reconstruction procedures. Besides tissue engineering, where living cells are used, bio-compatible polymers or synthetic resin can be applied. The combination of 3D handheld scanning devices or volumetric imaging, (open-source) image processing packages, and 3D printers form a complete workflow chain that is capable of effective rapid prototyping of outer ear replicas. This paper reviews current possibilities and latest use cases for 3D-scanning, data processing and printing of outer ear replicas with a focus on low-cost solutions for rehabilitation engineering.

Impact of intraoperative Cone-Beam Computed Tomography use on patient satisfaction after closed nasal reduction

Background: The aim of the study was to assess, whether there is a difference in aesthetic and functional patient satisfaction between closed nasal reductions with intraoperative Cone-Beam Computed Tomography (CBCT) and without using intraoperative medical imaging. Methods: A monocentric, retrospective cohort study of 43 patients (20 patients treated with intraoperative CBCT and 23 patients treated without intraoperative imaging) was conducted. Subjective postoperative aesthetic and functional aspects of the nose were assessed. Additionally, questions comparing the aesthetics and function of the nose before and after the accident and on the desire of revision surgery were asked. Results: Both the SCHNOS-C and total SCHNOS score in the non-CBCT group were higher than the respective scores of the CBCT-group. The comparison of SCHNOS-C between male subjects of the two groups showed no statistical significance. The comparison of SCHNOS-C between male and female subjects over both groups showed significantly higher scores for female subjects. Conclusions: Patients undergoing surgery with intraoperative CBCT imaging showed better aesthetical outcomes than patients, treated without intraoperative imaging. However, the difference showed no clinical importance, so that both strategies appear to have comparable outcomes regarding postoperative aesthetics and function of the nose. Gender instead of the different strategies could contribute to the demonstrated differences. Female subjects seem to be less satisfied with the aesthetics of their nose postoperatively, potentially being more sensitive to remaining nasal deformities after surgery.

Correlations between anatomical variations of the nasal cavity and ethmoidal sinuses on cone-beam computed tomography scans

Purpose

Anatomical variations of the external nasal wall are highly important, since they play a role in obstruction or drainage of the ostiomeatal complex and ventilation and can consequently elevate the risk of pathological sinus conditions. This study aimed to assess anatomical variations of the nasal cavity and ethmoidal sinuses and their correlations on cone-beam computed tomography (CBCT) scans.

Materials and Methods

This cross-sectional study evaluated CBCT scans of 250 patients, including 107 males and 143 females, to determine the prevalence of anatomical variations of the nasal cavity and ethmoidal sinuses. All images were taken using a New Tom 3G scanner. Data were analyzed using the chi-square test, Kruskal-Wallis test, and the Mann-Whitney test.

Results

The most common anatomical variations were found to be nasal septal deviation (90.4%), agger nasi air cell (53.6%), superior orbital cell (47.6%), pneumatized nasal septum (40%), and Onodi air cell (37.2%). Correlations were found between nasal septal deviation and the presence of a pneumatized nasal septum, nasal spur, and Haller cell. No significant associations were noted between the age or sex of patients and the presence of anatomical variations (P>0.05).

Conclusion

Radiologists and surgeons must pay close attention to the anatomical variations of the sinonasal region in the preoperative assessment to prevent perioperative complications.

[Standardization and modeling of surgical processes]

BACKGROUND

Due to the technological developments around the operating room, surgery in the twenty-first century is undergoing a paradigm shift.

OBJECTIVE

Which technologies have already been integrated into the surgical routine? How can a favorable cost-benefit balance be achieved by the implementation of new software-based assistance systems?

METHODS

This article presents the state of the art technology as exemplified by a semi-automated operation system for otorhinolaryngology surgery. The main focus is on systems for implementation of digital handbooks and navigational functions in situ.

RESULTS

On the basis of continuous development in digital imaging, decisions may by facilitated by individual patient models thus allowing procedures to be optimized. The ongoing digitization and linking of all relevant information enable a high level of standardization in terms of operating procedures. This may be used by assistance systems as a basis for complete documentation and high process reliability.

CONCLUSION

Automation of processes in the operating room results in an increase in quality, precision and standardization so that the effectiveness and efficiency of treatment can be improved; however, care must be taken that detrimental consequences, such as loss of skills and placing too much faith in technology must be avoided by adapted training concepts.

Indications of cone beam CT in head and neck imaging

CONCLUSION

Cone Beam Computed Tomography (CBCT) can be widely used in imaging of bony structures of the anterior and lateral skull base. Significant differences of applied dosages result from the different protocols of the various indications.

OBJECTIVES

CBCT is increasingly being used in head and neck imaging. Until now, no precise knowledge about its dedicated usage existed.

METHODS

All CBCT of 2012 and 2013 were analysed with regard to the technical parameters, the performance, and the indication for imaging.

RESULTS

In total, 1862 patients were examined in 2012 and 2013. The top eight indications of the anterior skull were (1) chronic rhinosinusitis with disturbed nasal breathing (30.3%); (2) chronic rhinosinusitis (17.6%); (3) midfacial traumatology (13.7%); (4) disturbed nasal breathing (12.8%); (5) acute rhinosinusitis (7.9%); (6) polyposis nasi (6.3%); (7) search for focus (3.9%); and (8) persistent rhinorrhea (1.2%). For the lateral skull base, the top eight were (1) control after cochlear implantation (28.4%); (2) cholesteatoma (19.7%); (3) visualization of ear anatomy (8.7%); (4) chronic otitis media mesotympanalis (6.3%); (5) conductive hearing loss (5.1%); (6) suspected mastoiditis (4.8%); (7) pathology of external auditory canal (4.8%); and (8) otosclerosis (3.3%). Applied dosage for the anterior skull base was significantly lower than for the lateral skull base (2.90 mGy vs 5.92 mGy, p < 0.05); 2.4% and 3.6% of patients' images, respectively, had to be repeated.

Normal Anatomy and Anatomic Variants of the Paranasal Sinuses on Computed Tomography

It is imperative for all imaging specialists to be familiar with detailed multiplanar CT anatomy of the paranasal sinuses and adjacent structures. This article reviews the radiologically relevant embryology of this complex region and discusses the region-specific CT anatomy of the paranasal sinuses and surrounding structures. Radiologists also need to know the clinical implications of identifying preoperatively the numerous anatomic variations encountered in this region and prepare a structured report according to the expectations of the referring clinician.

Differences of radiological artefacts in cochlear implantation in temporal bone and complete head

OBJECTIVES

Accurate radiological evaluation of cochlear implants is essential for improvement of devices and techniques and also for assessing the position of the electrodes within the cochlea. Radiological study of implants has focused on isolated temporal bones. Previous studies showed relevant sizes of artefacts (dimensions of the radiological image compared with the actual dimensions of the electrode) in visualization of cochlear implants in computed tomography and cone beam computed tomography (CBCT). In this study, we aimed to obtain CBCT images of cochlear electrodes in isolated temporal bones and in whole heads and to assess the differences in image quality between the two.

METHODS

Cochlear electrodes were implanted in three complete human heads. Radiological examinations were performed using a single CBCT scanner with varying x-ray tube currents, voltages, and rotation angles. The temporal bones were then removed and the same radiological examinations were repeated, with and without the receiver coils. Artefacts from a basal electrode (electrode 9) and an apical electrode (electrode 2) were calculated. These were compared with each other by measuring the diameter of the image of the electrode (electrode inclusive of imaging artefacts) and with the real electrode diameters from the manufacturer's data. Additionally, the radiological diameters (inclusive of artefact) of the electrodes were compared to the cross-sectional diameters of the basal and apical coils of the cochlea at the locations of these two electrodes.

RESULTS

In comparison to the real electrode diameters, radiological artefact proportions of 51-58% for electrode 9 and 56-61% for electrode 2 were calculated. The differences between whole head images (group 1) and temporal bone images with and without the receiver coil (groups 2 and 3) were highly significant for each protocol (P < 0.001).

DISCUSSION AND CONCLUSION

These results indicate that it is not possible reliably to determine the exact intracochlear positions of electrodes using CBCT. Imaging of isolated temporal bones produced significantly greater artefacts than imaging of the whole head. Evaluations of image quality based only on results for isolated temporal bones are not transferable to clinical situations, and should be assessed critically.

Phleboliths from venous malformations of the head and neck

Objectives/Hypothesis

Phleboliths in venous malformations (VM) of the head and neck are often observed and may cause significant symptoms. Only a few articles refer to the morphology and composition of the phleboliths in VM. The objective of this study was to analyse and to demonstrate their composition and morphology.

Methods

Patients with VM presenting to a vascular anomalies centre during a three-year period were identified. The incidence of phleboliths was analysed followed by morphological and structural analysis with cone beam tomography and X-ray diffraction.

Results

Phleboliths were identified in 28/98 patients with VM of the head and neck. Seven patients underwent conventional surgery to reduce the volume of the VM or to remove the phleboliths, which were localized in the cheek (3 cases), submandibular region (2 cases), infrahyoidal neck or upper eyelid (1 case each). The structural analysis showed that more advanced lamination and an increasing radiopacity of the cortex was observed in larger phleboliths. X-ray powder diffraction analysis revealed that the main constituent in the pulverized phleboliths was carbonate-fluorohydroxylapatite.

Conclusion

This study shows in a vivid way that phleboliths from VM of the head and neck area show a laminar structure and consist of apatite, without any indication of differences in their chemical composition. Treatment of localized intravascular coagulopathy in VM might be able to prevent the formation and the progression of phleboliths. Hypothetically, another option might be lithotripsy.

Analysis of pneumatization and neurovascular structures of the sphenoid sinus using cone-beam tomography (CBT)

BACKGROUND

The sphenoid sinus is a frequent target of paranasal sinus surgery. Because of the high risk of injuring the surrounding structures (e.g. internal carotid artery, optical nerve) a preoperative imaging is absolutely necessary.

PURPOSE

To analyze the possibilities of cone-beam computed tomography (CBCT), which is especially quite a new technique in ENT, in the evaluation of the sphenoid sinus, its surrounding structures, and the corresponding anatomical variations.

MATERIAL AND METHODS

This was a retrospective, single-centre study of 580 patients (1160 sides = cases). The Accu-I-Tomo-F17 was used. Pneumatization of sphenoid sinus, course of internal artery, course of optical nerve, and dehiscence of the bony canals were evaluated.

RESULTS

In the case of pneumatization a type I (completely missing or minimal sphenoid sinus) was found in two patients (0.3%), type II (posterior wall of sphenoid sinus is in front of the anterior wall of the sella) in 38 patients (6.6%), type III (posterior wall is between anterior and posterior wall of sella) in 332 patients (57,2%), type IVa (posterior wall is behind the posterior wall of sella without air dorsal the sella) in 104 patients (17.9%), and type IVb (similar to type IVa but with air dorsal the sella) in 104 patients (17.9%). In 1025 cases (89.5%) a smooth course of the internal carotid artery was found whereas a free course could be detected in 120 cases (10.5%). Defects of the bony canal of the optical nerve were found in 16.7% and of the internal carotid artery in 2.7% of the cases. The optical nerve showed a free course through the sphenoid in 151 cases (13.7%) and a smooth course in 1007 cases (87.0%).

CONCLUSION

CBCT could evaluate all relevant anatomic structures and answer the questions of different anatomical variants. A modified classification of the pneumatization of the sphenoid sinus could be described. Frequencies of anatomical variations are in accordance with the current literature of CT research.

Cone-beam computerized tomography imaging and analysis of the upper airway: a systematic review of the literature

A systematic review of the literature concerning upper airway imaging and analysis using cone-beam computed tomography (CBCT) was performed. A PubMed search (National Library of Medicine, NCBI; revised 9th January 2011) yielded 382 papers published between 1968 and 2010. The 382 full papers were screened in detail. 46 articles were considered clinically or technically relevant and were included in this systematic review. These were classified as articles on accuracy and reliability of CBCT imaging of the upper airway (n=4), accuracy and reliability of DICOM viewers (n=2), synopsis (n=10), technical (n=7) and clinical applications (n=27). When one paper was considered related to two or more categories, it was assigned to each relevant group. Results indicate that three-dimensional (3D) analysis of the upper airway using CBCT can be achieved in an accurate and reliable manner. Important obstacles still need to be addressed, including the impact of respiration phase, influence of tongue position and mandible morphology, longitudinal and cross-sectional 3D CBCT upper airway evaluation, and 3D CBCT definition of the anatomical boundaries of the upper airway.