Medical student experience with robot-assisted surgery after limited laparoscopy exposure.

The purpose of the study was to evaluate the objective and subjective experience of medical students completing robotic surgery tasks after limited laparoscopy exposure. Twenty-three medical students without previous laparoscopy and robotic surgery experience self-enrolled into 0 min (n = 11), 20 min (n = 6), and 40 min (n = 6) laparoscopy training groups. Subjects completed rope passing and ball placement tasks on a laparoscopy trainer before repeating similar tasks on the Senhance Surgical System, a robot-assisted digital laparoscopy device. Videos were recorded to evaluate objective measures including time, completion rate, clutch use, out of view instruments, ball drops, and manual adjustments. The NASA-TLX survey was administered to assess subjective experience using workload and task demand measures. There were no statistically significant differences in objective performance between the groups (p > 0.05). Subjects who completed laparoscopy training reported higher workloads, but these differences were not statistically significant (p > 0.05). NASA-TLX workload was correlated with time performance on Pearson and Spearman tests (r = 0.623, rho = 0.681, p < 0.01). Initial experience of medical students with robot-assisted surgery did not differ significantly after limited laparoscopy exposure.

Quantitative correlation between light depolarization and transport albedo of various porcine tissues.

We present a quantitative study of depolarization in biological tissues and correlate it with measured optical properties (reduced scattering and absorption coefficients). Polarized light imaging was used to examine optically thick samples of both isotropic (liver, kidney cortex, and brain) and anisotropic (cardiac muscle, loin muscle, and tendon) pig tissues in transmission and reflection geometries. Depolarization (total, linear, and circular), as derived from polar decomposition of the measured tissue Mueller matrix, was shown to be related to the measured optical properties. We observed that depolarization increases with the transport albedo for isotropic and anisotropic tissues, independent of measurement geometry. For anisotropic tissues, depolarization was higher compared to isotropic tissues of similar transport albedo, indicating birefringence-caused depolarization effects. For tissues with large transport albedos (greater than ~0.97), backscattering geometry was preferred over transmission due to its greater retention of light polarization; this was not the case for tissues with lower transport albedo. Preferential preservation of linearly polarized light over circularly polarized light was seen in all tissue types and all measurement geometries, implying the dominance of Rayleigh-like scattering. The tabulated polarization properties of different tissue types and their links to bulk optical properties should prove useful in future polarimetric tissue characterization and imaging studies.