Laparoscopy training of novices with complex curved instruments using 2D- and 3D-visualization.

PURPOSE: Beside many advantages, disadvantages such as reduced degrees of freedom and poorer depth perception are still apparent in laparoscopic surgery. 3D visualization and the development of complex instruments are intended to counteract the disadvantages. We want to find out whether the use of complex instruments and 3D visualization has an influence on the performance of novices. METHODS: 48 medical students with no experience in laparoscopic surgery or simulator-based laparoscopy training were included. They were randomized in four groups according to a stratification assessment. During a structured training period they completed the FLS-Tasks "PEG Transfer", "Pattern Cut" and "Intracorporeal Suture" and a transfer task based on these three. Two groups used conventional laparoscopic instruments with 3D or 2D visualization, two groups used complex curved instruments. The groups were compared in terms of their performance. RESULTS: In 2D laparoscopy there was a better performance with straight instruments vs. curved instruments in PEG Transfer and Intracorporeal Suture. In the transfer task, fewer errors were made with straight instruments. In 2D vs. 3D laparoscopy when using complex curved instruments there was an advantage in Intracorporeal Suture and PEG Transfer for 3D visualization. Regarding the transfer exercise, a better performance was observed and fewer errors were made in 3D group. CONCLUSION: We could show that learning laparoscopic techniques with complex curved instruments is more difficult with standard 2D visualization and can be overcome using 3D optics. The use of curved instruments under 3D vision seems to be advantageous when working on more difficult tasks.

A Robotic Camera Holder Controlled by Head Movements: Exploring This New Robot-Surgeon Interface.

Background. Most robotic camera steering devices (RCSDs) require active steering by the surgeon and necessarily increase workload. Clinical experience shows that standard laparoscopic procedures can be performed safely as solo surgery aided by RCSDs. No evidence exists concerning exploratory or emergency procedures. We compared the performance during unexpected laparoscopic tasks on surgical simulators aided either by an RCSD controllable by head movements of the surgeon or by a human camera assistant. Methods. Forty-five medical students without previous experience with minimal invasive surgery were randomized in 2 groups, and they performed standard and unexpected laparoscopic tasks requiring complex camera movements on box trainers either using an RCSD or assisted by a human camera assistant. Efficiency and performance parameters were recorded. Results. Performance in simulated standard procedures was equivalent. In simulated exploratory procedures, we saw significantly better performance scores in the conventional group versus the RCSD group. The strongest factor for these differences was the longer camera-adjusting time in the RCSD group versus the conventional group (PEG task = 208 ± 51 seconds vs 170 ± 36 seconds, P = .005; suture task = 563 ± 126 seconds vs 454 ± 201 seconds, P = .041). Conclusion. These results, obtained on surgical simulators, indicate that the solo approach to standard surgical tasks, facilitated by an RCSD controllable by head movements, can most likely be viewed as safe. Exploratory procedures with a relevant chance for complications or procedures that require rapid, often, or complex camera movements should rather be performed with a human camera assistant.

Sensory Qualities Point to Different Structural and Functional Skin Patterns in Chronic Pruritus Patients. A Translational Explorative Study.

Chronic pruritus (CP) is often accompanied by paresthetic sensations like warmth, burning and stinging. The aim of this study was to analyze, whether divergent sensations are linked to structural and functional skin alterations in clinically diagnosed CP patients. Clinical responses to capsaicin, histamine, and to thermal and mechanical stimulation, intraepidermal nerve fiber density, and epidermal expression of transient receptor potential (TRP)-channels were investigated in healthy controls, and in CP patients, reporting either warmth (CP-W) or neuropathic sensations (CP-N). In CP-W, pinprick hyperalgesia and increased sensitivity to capsaicin were aligned with increased epidermal TRPV1 expression, while smaller histamine axon reflex erythema matched with significantly reduced intraepidermal nerve fiber density. CP-N showed earlier onset of sensations after capsaicin stimulation, significantly increased warmth detection threshold, and higher epidermal expression of TRPV4 compared to healthy controls. The present study contributes to the neurobiological understanding of the divergence of sensory sensations in CP, indicating new treatment targets.