Ernest D. Gomez

Targeted loss of Arx results in a developmental epilepsy mouse model and recapitulates the human phenotype in heterozygous females

Mutations in the X-linked aristaless-related homeobox gene (ARX) have been linked to structural brain anomalies as well as multiple neurocognitive deficits. The generation of Arx-deficient mice revealed several morphological anomalies, resembling those observed in patients and an interneuron migration defect but perinatal lethality precluded analyses of later phenotypes. Interestingly, many of the neurological phenotypes observed in patients with various ARX mutations can be attributed, in part, to interneuron dysfunction. To directly test this possibility, mice carrying a floxed Arx allele were generated and crossed to Dlx5/6(CRE-IRES-GFP)(Dlx5/6(CIG)) mice, conditionally deleting Arx from ganglionic eminence derived neurons including cortical interneurons. We now report that Arx(-/y);Dlx5/6(CIG) (male) mice exhibit a variety of seizure types beginning in early-life, including seizures that behaviourally and electroencephalographically resembles infantile spasms, and show evolution through development. Thus, this represents a new genetic model of a malignant form of paediatric epilepsy, with some characteristics resembling infantile spasms, caused by mutations in a known infantile spasms gene. Unexpectedly, approximately half of the female mice carrying a single mutant Arx allele (Arx(-/+);Dlx5/6(CIG)) also developed seizures. We also found that a subset of human female carriers have seizures and neurocognitive deficits. In summary, we have identified a previously unrecognized patient population with neurological deficits attributed to ARX mutations that are recapitulated in our mouse model. Furthermore, we show that perturbation of interneuron subpopulations is an important mechanism underling the pathogenesis of developmental epilepsy in both hemizygous males and carrier females. Given the frequency of ARX mutations in patients with infantile spasms and related disorders, our data unveil a new model for further understanding the pathogenesis of these disorders.

Intraoperative Resident Education for Robotic Laparoscopic Gastric Banding Surgery: A Pilot Study on the Safety of Stepwise Education

BACKGROUND Incorporation of robotic surgery into resident education poses questions regarding intraoperative teaching and patient care. This study aimed to evaluate the impact of gradually increasing resident console responsibility on resident competency and patient safety, in the presence of a proctor and bedside surgeon, for robotic laparoscopic-assisted gastric banding (R-LAGB) compared with the classical training model (CTM) of residents as first assistant. STUDY DESIGN Eight clinical year 4 (CY4) residents completed 60 R-LAGB using a one-to-one proctored training model (PTM). R-LAGB was distilled into 7 key steps: gastroesophageal-junction dissection, gastrohepatic ligament dissection, retrogastric space creation, band placement, band closure, gastrogastric suturing, and port placement. Residents performed more complex steps after each case to gain competency in all aspects of the operation. Patient demographics, comorbidities, operative complications, operating times, and clinical outcomes were compared with a control group of 287 R-LAGB cases completed using the CTM (n = 15 CY4 residents). RESULTS All residents using the PTM were able to successfully complete an R-LAGB as primary surgeon after a median of 8 operations (range 5 to 11); no residents in the CTM completed an R-LAGB as primary surgeon. Mean operative time was statistically greater in the PTM group (99.3 ± 22.1 minutes) vs CTM (91.5 ± 21.1 minutes) (p = 0.001). There were no intraoperative complications in either group; incidence of postoperative complications was similar between groups. CONCLUSIONS All residents in the proctored setting claimed competence and have persistent console experience without significantly increasing procedure complications. PTM, otherwise known as stepwise education, is a safe, standardized method to train surgical residents in R-LAGB.

A Randomized Controlled Trial to Assess the Effects of Competition on the Development of Laparoscopic Surgical Skills.

BACKGROUND Serious games have demonstrated efficacy in improving participation in surgical training activities, but studies have not yet demonstrated the effect of serious gaming on performance. This study investigated whether competitive training (CT) affects laparoscopic surgical performance. METHODS A total of 20 novices were recruited, and 18 (2 dropouts) were randomized into control or CT groups to perform 10 virtual reality laparoscopic cholecystectomies (LCs). Competitiveness of each participant was assessed. The CT group members were informed they were competing to outperform one another for a prize; performance ranking was shown before each session. The control group did not compete. Performance was assessed on time, movements, and instrument path length. Quality of performance was assessed with a global rating scale score. RESULTS There were no significant intergroup differences in baseline skill or measured competitiveness. Time and global rating scale score, at final LC, were not significantly different between groups; however, the CT group was significantly more dexterous than control and had significantly lower variance in number of movements and instrument path length at the final LC (p = 0.019). Contentiousness was inversely related to time in the CT group. CONCLUSION This was the first randomized controlled trial to investigate if CT can enhance performance in laparoscopic surgery. CT may lead to improved dexterity in laparoscopic surgery but yields otherwise similar performance to that of standard training in novices. Competition may have different effects on novices vs experienced surgeons, and subsequent research should investigate CT in experienced surgeons as well.

A practical system for recording instrument interactions during live robotic surgery

We have developed a system for measuring and recording the high-frequency vibrations that characterize instrument interactions during minimally invasive robotic surgery. Consisting of simple circuitry and a DVD recorder, this system is low-cost and easily implementable, requires no sterilization, and enables measurement of a validated, objective technical skill metric in both the simulated setting and the operating room. The vibration recordings of fourteen sleeve gastrectomies were processed by segmenting the operation into seven phases and calculating the root mean square (RMS) vibration within each phase. Statistical analysis showed that the observed differences match expectations drawn from knowledge of the operation, substantiating the premise that RMS vibration provides a good measure of the intensity of instrument interactions during live robotic surgery.

Consumer-based technology for distribution of surgical videos for objective evaluation.

BackgroundThe Global Operative Assessment of Laparoscopic Skill (GOALS) is one validated metric utilized to grade laparoscopic skills and has been utilized to score recorded operative videos. To facilitate easier viewing of these recorded videos, we are developing novel techniques to enable surgeons to view these videos. The objective of this study is to determine the feasibility of utilizing widespread current consumer-based technology to assist in distributing appropriate videos for objective evaluation.MethodsVideos from residents were recorded via a direct connection from the camera processor via an S-video output via a cable into a hub to connect to a standard laptop computer via a universal serial bus (USB) port. A standard consumer-based video editing program was utilized to capture the video and record in appropriate format. We utilized mp4 format, and depending on the size of the file, the videos were scaled down (compressed), their format changed (using a standard video editing program), or sliced into multiple videos. Standard available consumer-based programs were utilized to convert the video into a more appropriate format for handheld personal digital assistants. In addition, the videos were uploaded to a social networking website and video sharing websites.ResultsRecorded cases of laparoscopic cholecystectomy in a porcine model were utilized. Compression was required for all formats. All formats were accessed from home computers, work computers, and iPhones without difficulty. Qualitative analyses by four surgeons demonstrated appropriate quality to grade for these formats.ConclusionsOur preliminary results show promise that, utilizing consumer-based technology, videos can be easily distributed to surgeons to grade via GOALS via various methods. Easy accessibility may help make evaluation of resident videos less complicated and cumbersome.

Evaluation of high-fidelity simulation as a training tool in transoral robotic surgery

To develop and evaluate a high‐fidelity training simulator for transoral robotic posterior hemiglossectomy.

Predictors of Initial Technical Skill Acquisition in Otorhinolaryngology Residency Applicants

Objectives: (1) Investigate the utility of residency applicant characteristics as predictors of technical skill. (2) Demonstrate the feasibility of technical skill assessment in the residency interview setting. Methods: A cross-sectional study was performed in December of 2013 to identify residency applicant characteristics that may predict technical skill. During 2 residency interview days, 39 medical students performed up to 5 trials each of 2 box trainer tasks: myringotomy and endoscopic grasping. Subject performance was assessed by an attending surgeon using a global rating scale (GRS). Completion time and error counts were recorded. Applicant factors studied were United States Medical Licensing Examination Step 1 score, Alpha Omega Alpha status, medical school grades, and extracurricular activities. Pearson coefficients and Wilcoxon rank-sum tests were used to evaluate each applicant characteristic. Results: A total of 117 endoscopic grasping trials and 179 myringotomy trials were assessed. Thirty-eight of 39 subjects completed both tasks at least 3 times. Participation in competitive sports was associated with more errors during the first endoscopic grasping trial (W = 110.5, P = .0036) with no difference found in subsequent trials. Step 1 scores and honors grades in core clerkships did not correlate with performance metrics for either task during any trial. Participation in competitive sports did not correlate significantly with task performance for myringotomy. Conclusions: Common methods of residency applicant assessment do not predict performance on otolaryngology-specific task trainers. It is feasible to measure initial technical skill acquisition in the residency interview setting. It is unknown whether initial technical skill acquisition will correlate with technical skill during residency.