Effect of surgeon experience on technical efficiency.

Surgeon experience certainly improves their technical efficiency although it also causes physiological changes with aging. The authors hypothesized that surgeons' technical efficiency improves with increasing experience up to a point where it then decreases, which is a concave relationship. The authors collected data from all the surgical procedures performed at University Hospital from April through September in 2013-19. The dependent variable was defined as surgeons' technical efficiency scores that were calculated using output-oriented Charnes-Cooper-Rhodes model of data envelopment analysis. Inputs were defined as (1) the number of assistants and (2) the duration of surgical operation. The output was defined as the surgical fee for each surgery. Surgeon experience was defined as the number of years since medical school graduation. Five control variables were selected: surgical volume, gender, academic rank, surgical specialty, and the year of surgery. Multiple regression analysis using pooled and random-effects Tobit models was performed for our panel data. Totally 20,375 surgical procedures performed by 264 surgeons in 42 months were analyzed. The coefficients of experience and the square of experience were not significantly different from zero. The other coefficients were also insignificant. Surgeons' technical efficiency does not have a concave relationship with experience.

[Thoracic Endovascular Aortic Repair for Stanford Type B Acute Aortic Dissection with Right Leg Malperfusion:Report of a Case].

We report a case of complicated Stanford type B acute aortic dissection with malperfusion to the right leg. The patient received conservative treatment in a previous hospital. However, he complained of pain in the right leg, which had been gradually turning pale. The patient was diagnosed with complicated Stanford type B acute aortic dissection with right leg malperfusion and was transferred to our hospital for treatment. Thoracic endovascular aortic repair (TEVAR) to close the entry to the distal aortic arch was performed, and we embolized the left subclavian artery to prevent type Ⅱ endoleak and to extend the stent-graft landing zone. We implanted a bare stent into the right external iliac artery to enlarge its true lumen. The patient was discharged from our hospital 22 days postoperatively. After the operation, computed tomography( CT) scan showed an aortic false lumen remodeling.