Rod-lens Telescopes Research Articles

TRACHEOBRONCHIAL FOREIGN BODIES

Aspirated and ingested foreign bodies continue to present challenges to otolaryngologists. The major issues involve the accurate diagnosis and speedy, safe retrieval of the foreign body. The accurate diagnosis may allude physicians because often the initial choking incidents are not witnessed and the delayed residual symptoms may mimic other common conditions. The retrieval of foreign bodies has been facilitated by technical improvements with the rod lens telescope, video endoscopy, a broad range of a variety of sized forceps, and safer anesthesia. This article reviews the clinical presentation, diagnostic work-up, and appropriate management of foreign bodies in the aerodigestive tract.

Rigid Bronchoscopic Removal of Multiple Airway Foreign Bodies

Despite new equipment, such as the Hopkins rod-lens telescopes and optical forceps, foreign bodies in the airway continue to present a diagnostic and therapeutic challenge to the endoscopist. Airway foreign bodies are more common in children than adults and frequently, the patient may have aspirated more than one foreign body or the original foreign body fragments into pieces. Vegetable matter is the most frequently aspirated material by children. This material can swell as it absorbs water, it can cause an intense mucosal reaction and it can fragment during removal. A case with endoscopic photographs demonstrating these issues and a discussion are presented.

Visualizing the pediatric airway: three-dimensional modeling of endoscopic images.

Three-dimensional reconstruction of medical images has emerged as an important visualization tool for studying complex anatomy. These tools have found important applications in neurology and plastic surgery using computed tomography (CT) and magnetic resonance imaging (MRI) data. However, CT and MRI do not sufficiently delineate lesions of the pediatric airway. Inspection through the rod lens telescope remains the standard diagnostic method. A video recording of an endoscopic procedure is essentially a sequence of two-dimensional images captured as the telescope traverses the airway lumen. Using digitized endoscopic video recordings and computer graphics reconstruction techniques, we have developed a preliminary three-dimensional modeling system for the pediatric airway. A series of normal and abnormal telescopic airway examinations were video recorded. Serial sections were obtained by digitizing the video images at uniform intervals as the scope traversed the airway lumen between the vocal folds and the carina. The digitized images were calibrated and used to reconstruct the airway lumen in three dimensions. Classifying airway abnormalities according to the minimal cross-sectional area or with descriptive terms can be subjective and dependent on the endoscopist's observational skills. We hope that this preliminary work will lead to more precise and understandable methods for representing complex airway lesions.

Transnasal Repair of Choanal Atresia Using Telescopes

Choanal atresia, consisting of a unilateral or bilateral bony or membranous septum between the nose and the pharynx, occurs in approximately one of 7000 live births. Conventional treatment has consisted of watchful observation and elective surgical repair or immediate intervention using a variety of surgical techniques. We attempted transnasal repair using a telescope to remedy the obstruction. Over an 18-month period, six female and four male patients, who were between 3 weeks and 14 years of age at the time of surgery, underwent transnasal repair of unilateral or bilateral choanal atresia with the aid of a rod-lens telescope. All 10 patients had nasal stents made from endotracheal tubes that were fixed with sublabial and transseptal sutures. Seven patients remain free of symptoms 18 to 24 months after surgery. Three patients required revision surgery. Two of the revision cases recovered completely, with no restenosis 12 months after the second surgery. There were no postoperative complications. Transnasal repair of choanal atresia using a rod-lens telescope appears to be an effective procedure with low morbidity.

Continuous flow resectoscopes. Are the theory and design wrong?

The optical design of rod-lens telescopes has now reached a zenith. The only way of improving the resectoscope is to investigate the ergonomics and flow dynamics. We present a comparative analysis of the flow mechanics of continuous flow resectoscopes. The morphology, flow characteristics and irrigating potential (washout gradient) of several instruments were examined. It was found that when used with balanced continuous flow (inflow and outflow balanced), all of the endoscopes had poor visibility compared with unbalanced continuous flow (inflow > outflow). Possible changes in the design of the instruments are discussed.

Electronic imaging in endoscopy.

Endoscopy evolved from a hollow tube view of visually restricted areas into an expansive, distal representation of the anatomy. Rod lens telescopes, improved coherent imaging bundles, superior light sources, and other optical advances enhanced endoscopic observations. Yet complicated endoscopic procedures remained visible to the endoscopist alone, relegating assistance and consultation to verbal description of sophisticated visual observation. Instrumentational advances alone did not promote three crucial elements: participation, cooperation and documentation. The importance of these elements has increased with the need for coordinated assistance in complex operative endoscopic manipulations, as well as in a visual record for improved documentation and consultation. New imaging technologies are supplanting the unwieldy, often daunting equipment once required for photodocumentation. The charged couple device (CCD) 2/3 and 1/2 in. "chip" video camera miniaturization provides nearly weightless TV coobservation. Distal chip placement has created the "video endoscope". Combined with the 8 mm tape format, the chip has created a lightweight, single unit camera, monitor, and recorder. A recent advantage, magnetic disc recording, permits still video storage of up to 25 images. An electronic printer produces a hard color copy (4 x 5), which is inserted in the chart before the patient leaves the endoscopy room. The cost of the equipment can be shared in multidisciplinary institutions.