The learning curve for gasless transaxillary posterior endoscopic thyroidectomy for thyroid cancer: a cumulative sum analysis

Gasless transaxillary posterior endoscopic thyroidectomy (GTPET) is a new approach for thyroid cancer. It allows en bloc resection of the thyroid and central lymph nodes. Few studies have reported on the learning curve for GTPET.We examined the learning curve of GTPET for thyroid cancer by cumulative sum (CUSUM) analysis by retrospectively analyzing patients who underwent hemithyroidectomy with ipsilateral central neck dissection between December 2020 and September 2021 at a tertiary medical center, including the first patient. Moving average analysis and sequential time-block analysis were used for validation. Data on the clinical factors between the two periods were compared. In the overall cohort, the average time for GTPET for thyroid cancer was 113.25 min to harvest an average of 6.4 central lymph nodes. The CUSUM curve of the operative time indicated an inflection point after 38 patients. Moving average analysis and sequential time-block analysis validated the number of procedures needed for GTPET proficiency. (124.05 min vs. 107.63 min for the unproficient period vs. proficient period, respectively; P