Search PubMedSearch

PubMed · 8473205

[3D endoscopy].

Abstract

With the aid of a 6 mm 0 degree stereo-endoscope supplied with a 100 Hz monitor and high-speed liquid crystal shutter, three-dimensional endoscopy of the upper airway was realized for the first time. The equipment used is based on alternating sequential projections of left and right eye images on a single tv screen. Two high-speed liquid crystal stereo switches (LCSS) are integrated in glasses and a rapid switching time of 100 microseconds is used. In a comparative study this innovative endoscopic technique was tested for its practicability in sinus surgery and endoscopy of the upper airway. With this equipment an excellent view was obtained of the pharynx, larynx and trachea. For sinus surgery, however, a stereoendoscope with smaller dimensions has to be developed.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

J Strutz. 1993. [3D endoscopy].. https://pubmed.ncbi.nlm.nih.gov/8473205/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Assessment of shoulder dimensions and angles of porcelain bonded to metal crown preparations.

The metal ceramic crown is the most popular extracoronal restoration in the United Kingdom. These restorations may fail because of fracture or esthetics. A potential cause of failure is the quality and width of the facial shoulder preparation. In this study 24 extracted human teeth were prepared to receive metal ceramic crowns by one of three dentists. Preparations were replicated and scanned in the midfacial plane by a coordinate measuring machine with a noncontact probe. The x, y, and z surface coordinates were recorded. The results indicated a mean (+/-SD) shoulder width value of 0.752 mm (+/-0.174 mm) and a shoulder angle of 108.54 (+/-15.06) degrees. From these data it would appear that there are deficiencies in shoulder preparations, particularly in width. These inadequacies may have implications for longevity of the restoration and periodontal health in a clinical situation.

Computer Graphics

Fibre recruitment and shape changes of knee ligaments during motion: as revealed by a computer graphics-based model.

A computer graphics-based model of the knee ligaments in the sagittal plane was developed for the simulation and visualization of the shape changes and fibre recruitment process of the ligaments during motion under unloaded and loaded conditions. The cruciate and collateral ligaments were modelled as ordered arrays of fibres which link attachment areas on the tibia and femur. Fibres slacken and tighten as the ligament attachment areas on the bones rotate and translate relative to each other. A four-bar linkage, composed of the femur, tibia and selected isometric fibres of the two cruciates, was used to determine the motion of the femur relative to the tibia during passive (unloaded) movement. Fibres were assumed to slacken in a Euler buckling mode when the distances between their attachments are less than chosen reference lengths. The ligament shape changes and buckling patterns are demonstrated with computer graphics. When the tibia is translated anteriorly or posteriorly relative to the femur by muscle forces and external loads, some ligament fibres tighten and are recruited progressively to transmit increasing shear forces. The shape changes and fibre recruitment patterns predicted by the model compare well qualitatively with experimental results reported in the literature. The computer graphics approach provides insight into the micro behaviour of the knee ligaments. It may help to explain ligament injury mechanisms and provide useful information to guide the design of ligament replacements.

Computer Graphics