Robust, Low-Cost Laparoscope Could Improve Surgical Outcomes Worldwide

Laparoscopic surgery, a minimally invasive surgical technique for the chest and abdomen, significantly reduces post-procedure morbidity compared to open surgery. Despite its advantages, laparoscopic surgery remains largely inaccessible in low- and middle-income countries (LMICs) due to the high cost of the equipment and other logistical challenges.

To address this disparity, researchers at the University of Maryland, Makerere University, and Duke University developed a low-cost, durable, reusable, single-unit laparoscopic system, called KeyScope, using miniaturized CMOS and LEDs.

Standard-of-care (SOC) laparoscopes typically include a laparoscopic camera unit that contains a microelectronic video camera with a high-resolution CCD, a high-intensity light source coupled to a fiber optic light guide cable, rigid optics to transmit light through the body to the camera, and a digital video unit to record, process, and visualize video from the camera on a monitor.

At about $130,000 per unit, the cost of SOC laparoscopes is prohibitive for most LMICs. Also, the equipment used in SOC units is fragile and frequently in need of repair.

By replacing the delicate lens systems and fiber optic cables with LEDs and a CMOS detector at the device tip, the research team reduced the price of the KeyScope to about $1000, making its cost viable for LMICs.

A computer-aided design rendering of the low-cost laparoscope, called the KeyScope (left). KeyScope enables high resolution surgical imaging with a wide field of view, color accuracy, and low distortion, resulting in KeyScope images (right) comparable to a SOC laparoscopic device. Courtesy of Barnes et al., doi 10.1117/1.BIOS.2.2.022302.

The KeyScope connects to a laptop via a USB. The USB is used to power the device and send video data from the laparoscope to the laptop, which acts as the processing unit. This eliminates the need for expensive monitors and enables surgeons to continue to use the device for approximately two additional hours during power outages, or longer with additional laptop battery support. In areas with unreliable power sources — the case for many LMICs — this capability is crucial.

The device has a waterproof design and no detachable parts, making it suitable for submersion sterilization, a sterilization process that is commonly used in LMICs.

The researchers optimized the performance of the KeyScope using an iterative, human-centered design approach. They improved several design aspects over numerous iterations, providing enhanced image resolution at longer working distances, increasing light output, and testing the device’s performance in vivo.

To improve the light output, the team used a strobe approach, where LEDs were pulsed to increase the light intensity while simultaneously reducing heat production. The LEDs are pulsed in sync with the frame clock of the camera. Consequently, the LEDs always appear to be “on” to the surgeon viewing the video stream.

Pilot manufacturing of the third-generation KeyScope was performed in a local makerspace in Uganda to assess manufacturing feasibility in an LMIC. This enabled the researchers to identify the steps necessary to increase the efficiency and ease of the assembly process.

To evaluate the KeyScope performance in vivo, the third-generation design was tested in swine, a commonly used model for laparoscopy. Through in vivo testing, the researchers observed that cautery tools occasionally interfered with the video stream from the device when the ground pad was inadequately adhered to the subject. Thus, in the fourth-generation design, the camera and LEDs were electrically isolated from the device’s metal housing.

Each generation of the KeyScope was tested via a series of bench tests in a portable optical testing chamber to ensure image quality was preserved.

When the researchers compared standard image quality metrics from the KeyScope to a commercially available SOC laparoscope, they found that the resolving power, lens distortion, field of view, depth of field, and color reproduction accuracy in the enhanced version of the KeyScope were comparable or better than that of an SOC laparoscope at the distances commonly used during laparoscopic surgery. These results suggest that with the researchers achieved the performance criteria needed for laparoscopic procedures in LMICs with the KeyScope.

A company in Uganda demonstrated the capability to produce the device, ensuring that it can be serviced and distributed in Africa. The intent is to localize use of the KeyScope in resource-challenged areas and make it easy for LMICs to maintain.

The KeyScope could benefit hospitals that do not have access to laparoscopic equipment, and therefore perform open procedures, and hospitals that may have access to SOC laparoscopic equipment but find the equipment difficult to maintain.

Many could benefit by making laparoscopic surgery accessible to more patients worldwide. By addressing the specific needs and constraints of LMICs, the KeyScope has the potential to improve surgical outcomes and save lives in regions where advanced medical equipment is scarce.

The research was published in Biophotonics Discovery (www.doi.org/10.1117/1.BIOS.2.2.022302).