Can Computerized Simulation be Used to Assess Surgical Proficiency in Laparoscopic Colorectal Surgeries? A Systematic Review.

INTRODUCTION: Computerized simulation (CS) of surgery in virtual reality (VR), augmented reality (AR) and mixed reality (MR) settings are used to teach foundational skills, but its applicability in advanced training is to be determined. This review aims to summarize the types of CS available for laparoscopic colorectal surgery (CRS) and its utility in assessment of proficiency. METHODS: A systematic review of CS in laparoscopic CRS was done on PubMed, Embase, Scopus and Cochrane Library databases. RESULTS: Eleven relevant observational studies were identified. The most common procedure simulated was laparoscopic colectomy. Assessment using performance metrics measured by the simulator such as path length moved by laparoscopic tools, procedure time and number of discrete movements had the most consistent differentiating ability between expert and non-expert cohorts. Surgeons fared similarly in proficiency scores in assessment with CS compared to assessment with traditional cadaveric or porcine models. CONCLUSION: CS of laparoscopic CRS may be used in assessment of proficiency using performance metrics measuring economy of movement. CS may be a viable assessment tool in advanced surgical training, but further studies should assess utility of incorporating it as a formal assessment tool in training programs.

Novel function of PIWIL1 in neuronal polarization and migration via regulation of microtubule-associated proteins.

BACKGROUND: Young neurons in the developing brain establish a polarized morphology for proper migration. The PIWI family of piRNA processing proteins are considered to be restrictively expressed in germline tissues and several types of cancer cells. They play important roles in spermatogenesis, stem cell maintenance, piRNA biogenesis, and transposon silencing. Interestingly a recent study showed that de novo mutations of PIWI family members are strongly associated with autism. RESULTS: Here, we report that PIWI-like 1 (PIWIL1), a PIWI family member known to be essential for the transition of round spermatid into elongated spermatid, plays a role in the polarization and radial migration of newborn neurons in the developing cerebral cortex. Knocking down PIWIL1 in newborn cortical neurons by in utero electroporation of specific siRNAs resulted in retardation of the transition of neurons from the multipolar stage to the bipolar stage followed by a defect in their radial migration to the proper destination. Domain analysis showed that both the RNA binding PAZ domain and the RNA processing PIWI domain in PIWIL1 were indispensable for its function in neuronal migration. Furthermore, we found that PIWIL1 unexpectedly regulates the expression of microtubule-associated proteins in cortical neurons. CONCLUSIONS: PIWIL1 regulates neuronal polarization and radial migration partly via modulating the expression of microtubule-associated proteins (MAPs). Our finding of PIWIL1's function in neuronal development implies conserved functions of molecules participating in morphogenesis of brain and germline tissue and provides a mechanism as to how mutations of PIWI may be associated with autism.