Improving Neurosurgery Resident Microdissection Through Placental Simulation

ABSTRACT Prior work has shown that the human placenta is an available and realistic model for microdissection simulation. We sought to find a measurable improvement in the technical skills of neurosurgical residents with deliberate practice of microdissection tasks using a placental model. Postgraduate year (PGY) 1 to 3 neurosurgery residents were consented. A 1-min video of each participant's baseline skills skeletonizing placental vessels was recorded. Participants underwent 10 practice sessions with intermittent informal feedback for 30-60 min over 18 mo. Another 1-min video was recorded following the 10th dissection. The videos were blinded and assessed by 3 board eligible or certified microsurgical neurosurgeons using a modified Objective Structured Assessment of Aneurysm Clipping Skills. Performance was compared via t-testing among four domains: instrument handling, time flow and forward planning, quality of dissection, and respect for tissue. Microdissection, instrument handling, and quality of dissection were significantly improved after deliberate practice with the placental simulator (P < .05). Improvement was seen in time flow and forward planning and respect for tissue; however, this failed to be significant. Subjectively, residents expressed enjoyment performing the exercise. They also expressed a desire for demonstrations or videos to watch before practice sessions. The placental simulation model provides microsurgical skill development with minimal deliberate practice sessions. Practice exercises are favorably regarded and interest in continuing them is strong by residents. Residents expressed a desire to make the dissection more deliberate with demonstration, breakdown of steps, and mimicry, which could improve the effectiveness and enjoyment of the skills session.

The Water Channel Aquaporin 8 is a Critical Regulator of Intestinal Fluid Homeostasis in Collagenous Colitis

Background and Aims Diarrhoea is a common, debilitating symptom of gastrointestinal disorders. Pathomechanisms probably involve defects in trans-epithelial water transport, but the role of aquaporin [AQP] family water channels in diarrhoea-predominant diseases is unknown. We investigated the involvement of AQPs in the pathobiology of collagenous colitis [CC], which features chronic, watery diarrhoea despite overtly normal intestinal epithelial cells [IECs]. Methods We assessed the expression of all AQP family members in mucosal samples of CC patients before and during treatment with the corticosteroid drug budesonide, steroid-refractory CC patients and healthy controls. Samples were analysed by genome-wide mRNA sequencing [RNA-seq] and quantitative real-time PCR [qPCR]. In some patients, we performed tissue microdissection followed by RNA-seq to explore the IEC-specific CC transcriptome. We determined changes in the protein levels of the lead candidates in IEC by confocal microscopy. Finally, we investigated the regulation of AQP expression by corticosteroids in model cell lines. Results Using qPCR and RNA-seq, we identified loss of AQP8 expression as a hallmark of active CC, which was reverted by budesonide treatment in steroid-responsive but not refractory patients. Consistently, decreased AQP8 mRNA and protein levels were observed in IECs of patients with active CC, and steroid drugs increased AQP8 expression in model IECs. Moreover, low APQ8 expression was strongly associated with higher stool frequency in CC patients. Conclusion Down-regulation of epithelial AQP8 may impair water resorption in active CC, resulting in watery diarrhoea. Our results suggest that AQP8 is a potential drug target for the treatment of diarrhoeal disorders.