Compact light-emitting diode lighting ring for video-assisted thoracic surgery

Affordable Laparoscopic Camera System (ALCS) Designed for Low- and Middle-Income Countries: A Feasibility Study

BACKGROUND

Minimally invasive surgical techniques (MISTs) could have tremendous benefits in resource-poor environment. There is growing interest in MISTs in most low- and middle-income countries (LMIC), but its adoption has remained limited; this is largely due to high cost of the initial setup, lack of technological backup and limited access to training among others. An affordable laparoscopic setup will go a long way in improving access to MISTs.

METHODS

A common zero degrees 10 mm scope is attached on the camera of a low-price smartphone. Two elastic bands are used to fix the scope right in front of the smartphone's main camera; alternatively, a low-cost camera coupler can be used. The device is covered with sterile transparent drapes and a light source connected with a fiber-optic cable for endoscopic use. The image can be seen in real time on a common TV screen through an HDMI connection to the smartphone, with a sterile drape.

RESULTS

We were able to perform the five tasks of the Fundamentals of Laparoscopic Surgery curriculum, using our vision system with proficiency. In a pig model, we performed a tubal ligation to simulate an appendectomy and we were able to suture. No major differences were measured between the two connection systems.

CONCLUSIONS

A low-cost laparoscopic camera system can benefit surgeons and trainees in LMICs. The system is already attractive for use during training, but further studies are needed to evaluate its potential clinical role in LMICs.

Miniature ureteroscope distal tip designs for potential use in thulium fiber laser lithotripsy

Thulium fiber laser lithotripsy using smaller optical fibers may enable development of miniature ureteroscopes. Two ureteroscope distal tip prototypes were built and characterized. The first design was 4.5-French (Fr) [1.5-mm outer diameter (OD)], five channel tip, housing 200-μm inner diameter (ID) dedicated central channel for insertion of 100-μm core fibers and four surrounding channels, each with 1.5 Fr (510-μm ID) for instrumentation, irrigation, imaging, and illumination, respectively. The second design was 6.0-Fr (2.0-mm OD), three-dimensional printed tip with larger, hemispherical common working channel and separate detection port integrated with ring lighting. Standard instruments, including optical fibers, guidewires, and stone baskets, were inserted through working channels to demonstrate feasibility. Gravitational and manual pump-assisted saline irrigation rates were measured. Luminous intensity distribution curves (LIDCs) were modeled for both ring and conventional lighting designs. Imaging was conducted using 3000, 6000, and 10,000 pixel, miniature, flexible endoscopes with 0.4-, 0.6-, and 0.9-mm OD, to differentiate between urinary stones and ureter wall, for potential clinical application. The multichannel ureteroscope tip with 1.5-Fr working channel yielded a gravitational saline flow rate of 3.9  ±  0.2  mL  /  min compared to 31.3  ±  0.6  mL  /  min for standard (3.6 Fr) ureteroscope channel. Manual, pump-assisted irrigation increased flow rate to 32.5  ±  3.0  mL  /  min. The 6000 pixel, 0.6-mm OD, flexible endoscope provided a balance of clear differentiation between stones and ureter wall and sufficiently small OD. A ring lighting configuration provided more uniform illumination than conventional cross-lighting geometry as demonstrated by LIDCs. With further development, these miniature ureteroscope tip designs may be integrated into a fully functional ureteroscope to permit ureteral access with minimal trauma and improved patient safety and comfort.

Supercontinuum as a light source for miniaturized endoscopes

In this work, we have successfully implemented supercontinuum based illumination through single fiber coupling. The integration of a single fiber illumination with a miniature CMOS sensor forms a very slim and powerful camera module for endoscopic imaging. A set of tests and in vivo animal experiments are conducted accordingly to characterize the corresponding illuminance, spectral profile, intensity distribution, and image quality. The key illumination parameters of the supercontinuum, including color rendering index (CRI: 72%~97%) and correlated color temperature (CCT: 3,100K~5,200K), are modified with external filters and compared with those from a LED light source (CRI~76% & CCT~6,500K). The very high spatial coherence of the supercontinuum allows high luminosity conduction through a single multimode fiber (core size~400μm), whose distal end tip is attached with a diffussion tip to broaden the solid angle of illumination (from less than 10° to more than 80°).