USE OF THREE-DIMENSIONAL ENDOSCOPY IN ENDONASAL AND ANTERIOR SKULL BASE SURGERY

Objectives: The three dimensional (3D) endoscope is considered as a new surgical tool which used in different approaches in intranasal and anterior skull base surgical procedures. There are many advantages of the 3D endoscopy over the two dimensional (2D) one that have been demonstrated along clinical applications, surgical training and different experimental studies. Our study aimed to show the difference between using the 3D & 2D endoscopes during endonasal and anterior skull base surgery and its importance specially when used by novice users. Design: Our study is divided into two phases (clinical & cadaveric phases).In the clinical study we have done 52 endonasal & anterior skull base surgical procedures (26 study cases and 26 control cases).We recorded accuracy, duration and intraoperative complication for each case. The cadaveric study was performed on three cadavers, difference in accuracy and dissection time were recorded using 3D & 2D endoscopy for each side chosen by randomization. Results: In the clinical study, the cases done by 3D endoscope were significantly faster and more accurate with less intraoperative complications compared to cases done using 2D endoscope. In cadaveric dissection while using 3D endoscope there was better depth of perception regarding the anatomical landmarks compared to 2D endoscope. Conclusion: 3D endoscopy is an advanced instrument that allows better training for the coming generation of ENT surgeons. Both clinical and cadaveric studies offer a promising outcomes in both endonasal and anterior skull base surgery.

Endoscopic measurement of nasal septum perforations

Background Nasal septum perforations (NSP) have many uncomfortable symptoms for the patient and a highly negative impact on quality of life. NSPs are closed using patient-specific implants or surgery. Implants are created either under anesthesia using silicone impressions or using 3D models from CT data. Disadvantages for patient safety are the increased risk of morbidity or radiation exposure. Materials and methods In the context of otorhinolaryngologic surgery, we present a gentle approach to treating NSP with a new image-based, contactless, and radiation-free measurement method using a 3D endoscope. The method relies on image information only and makes use of real-time capable computer vision algorithms to compute 3D information. This endoscopic method can be repeated as often as desired in the clinical course and has already proven its accuracy and robustness for robotic-assisted surgery (RAS) and surgical microscopy. We expand our method for nasal surgery, as there are additional spatial and stereoperspective challenges. Results After measuring 3 relevant parameters (NSP extension: axial, coronal, and NSP circumference) of 6 patients and comparing the results of 2 stereoendoscopes with CT data, it was shown that the image-based measurements can achieve comparable accuracies to CT data. One patient could be only partially evaluated because the NSP was larger than the endoscopic field of view. Conclusion Based on the very good measurements, we outline a therapeutic procedure which should enable the production of patient-specific NSP implants based on endoscopic data only.

Surgical Guidance for Removal of Cholesteatoma Using a Multispectral 3D-Endoscope

We develop a stereo-multispectral endoscopic prototype in which a filter-wheel is used for surgical guidance to remove cholesteatoma tissue in the middle ear. Cholesteatoma is a destructive proliferating tissue. The only treatment for this disease is surgery. Removal is a very demanding task, even for experienced surgeons. It is very difficult to distinguish between bone and cholesteatoma. In addition, it can even reoccur if not all tissue particles of the cholesteatoma are removed, which leads to undesirable follow-up operations. Therefore, we propose an image-based method that combines multispectral tissue classification and 3D reconstruction to identify all parts of the removed tissue and determine their metric dimensions intraoperatively. The designed multispectral filter-wheel 3D-endoscope prototype can switch between narrow-band spectral and broad-band white illumination, which is technically evaluated in terms of optical system properties. Further, it is tested and evaluated on three patients. The wavelengths 400 nm and 420 nm are identified as most suitable for the differentiation task. The stereoscopic image acquisition allows accurate 3D surface reconstruction of the enhanced image information. The first results are promising, as the cholesteatoma can be easily highlighted, correctly identified, and visualized as a true-to-scale 3D model showing the patient-specific anatomy.

A multispectral 3D-Endoscope for Cholesteatoma Removal

We present a stereo-multispectral endoscopic prototype using a filter-wheel to guide the removal of cholesteatoma tissue in the middle ear. An image-based method is used that combines multispectral tissue classification for the detection of tissue to be removed and 3Dreconstruction to determine its metric dimensions. The multispectral illumination used for tissue classification ranges from λ = 400 nm to λ = 500 nm with step-size of 20 nm, which results in six different narrow-band illumination modes. For classical RGB imaging and metric calculations, a broadband illumination mode is applied before and after the narrow-band illumination. The spectral information is augmented into the broadband mode using an overlay technique. The combination of multispectral imaging with stereoscopic 3D-reconstruction results in new valuable visualization of intraoperative data. This allows to generate a 3D-model of the patients anatomy highlighting the identified malicious tissue and compare the anatomical dimensions with pre-operative CT data.

Endoscopic versus Microscopic Transsphenoidal Hypophysectomy: Comparison of the Endocrine Outcome – An Institutional Experience

BACKGROUND: The transnasal transsphenoidal endoscopic approach to the sella turcica is an overwhelming alternative to the microscopic approach for the past few decades assuming into prominence as a new technique, reaching nearly gold standard for this pathology. The endoscopic approach to the pituitary has redefined accurate visualization of the sella. The panoramic view afforded by the endoscope is unparalleled as compared with the traditional conical view of the microscope. AIMS: This study aims to compare both endoscopic and microscopic technologies, including advantages and disadvantages through the results of endocrine outcome. SETTINGS AND DESIGN: Our retrospective/prospective study included 46 microscopically and 39 endoscopically treated patients during the period of 2010–2018. Tumors were classified according to the diameter and clinical outcomes were evaluated. RESULTS: Our retrospective/prospective study included 46 microscopically and 39 endoscopically treated patients during the period of 2010–2018. Tumors were classified according to the diameter, hormone activity and clinical outcomes were evaluated. Comparison results revealed more efficacious and effective endocrine control and reestablishing the endocrine homeostasis utilizing the endoscopic technique, especially in secretory active macroadenomas. Further, the extension of the resection, which was better in endoscopic approach undouptedly contributed to better endocrine control of the disease. Complication rate, including endocrine, was lower following endoscopy compared with microsurgery. CONCLUSION: This technique evidenced to have a statistically significant reduction in operative time and length of hospital stay, as well as more radical safe resection and complication control. There is also a trend toward improved endocrine outcomes and rate of return of visual defects. These two approaches are still comparable with eloquent advantages and disadvantages, formulated as balanced dialectics. In addition, the use of endoscopes, including multilocular polifilament 3D endoscope, facilitates extended approaches, reaching a delicate skull base lesions that are suprasellar, retrosellar, and parasellar, which permits visualization beyond the abilities of the microscope.