Development of a Low-Cost Laparoscope

Abstract

Laparoscopic surgery significantly improves clinical outcomes over open procedures by reducing infection risks, postoperative pain, and recovery times. However, in low- and middle-income countries (LMICs), the widespread adoption of minimally invasive surgery remains severely restricted by the high acquisition costs, continuous electrical power demands, and fragile optical architectures of conventional laparoscopic tower systems. This thesis presents the design, development, and validation of an ultra-low-cost, modular USB laparoscope engineered as a direct replacement for commercial instruments in routine surgical procedures.

Adopting a human-centered, context-driven design methodology, functional requirements were formulated through a literature review, live surgical observations, and semi-structured interviews with healthcare professionals experienced in low-resource environments. These evaluations established that device robustness, ease of reprocessing, and on-site repairability decisively outweigh kinematic versatility and minor cost differences.
In the preliminary phase, four commercial-off-the-shelf (COTS) CMOS camera modules were quantitatively benchmarked against state-of-the-art clinical laparoscopic towers (Stryker 1688 and Olympus OTV-S7) using standardized ISO optical metrics. While the commercial reference systems demonstrated wider diagonal fields of view and superior low-light robustness, the low-cost CMOS modules exhibited lower color reproduction errors (Delta E and Delta C) and significantly reduced geometric barrel distortion (under -1.8% versus up to -4.9%). The 2-megapixel GC2755 module was selected for prototype integration due to its superior spatial sharpness at functional working distances (20–50 mm) and its compact footprint, which uniquely enabled a fixed 30-degree oblique viewing angle within a standard 12 mm outer diameter stainless steel shaft.
A functional prototype was fabricated incorporating an in-shaft distal housing with isolated forward-facing LED channels, an independent acrylic optical window, and a modular, two-part PETG handle featuring an elastomeric O-ring seal, brass cable gland, and tactile orientation indicator. Manufactured at a total component bill of materials (BOM) cost of €45.53, the scope interfaces directly via a single 5V USB cable to a standard laptop, eliminating infrastructural dependencies on external light sources and dedicated processing units.

Mechanical characterization confirmed structural resilience under operational tensile (25 N), torsional (1.7 Nm), and transverse bending loads. Thermal testing verified that steady-state operating temperatures at the distal tip plateau at 38.1°C, remaining safely below the 48°C tissue-injury threshold while closely matching physiological core body temperature (37°C), providing an intrinsic anti-fogging effect. Finally, an evaluative usability study with six practicing surgical professionals yielded a median System Usability Scale (SUS) score of 83.75 (mean 83.75 ± 9.05), substantially exceeding the 68-point clinical acceptability baseline. The participating surgeons confirmed that the prototype can be operated intuitively without retraining and possesses adequate optical fidelity for diagnostic and basic surgical procedures, establishing a viable foundation for accessible minimally invasive surgery in resource-constrained settings.