Learning curve and volume outcome relationship of endoscopic trans-oral versus trans-axillary thyroidectomy; A...

In the modern era, minimally invasive surgery is rapidly evolving and even replacing conventional open techniques in many surgical fields. Thyroidectomy was not an exception, with the introduction of multiple endoscopic thyroidectomy techniques. Trans-oral endoscopic trans-vestibular thyroidectomy (TOT) is a novel technique with promising outcomes. We conducted this meta-analysis to compare surgical outcomes and learning curves for TOT and other endoscopic thyroidectomy techniques.

A systematic review in PubMed, MEDLINE, and EMBASE databases was conducted searching for publications on TOT versus trans-axillary thyroidectomy (TAT). The primary endpoint was operative (OR) time. Secondary endpoints were number of harvested lymph nodes (LNs), estimated blood loss (EBL), recurrent laryngeal nerve (RLN) injury, hoarseness, seroma, infection, chyle leak, hypocalcemia, hospital length of stay (LOS), and Cost. We also investigated the learning curve for each technique. Leave-out-out analysis, meta-regression, and subgroup analysis were used. Random effect inverse variance method was utilized.

Among 3820 retrieved studies, 15 studies (10 unmatched and 5 matched), with 2173 (TOT: 1024(47.12%) and TAT:1149(52.87%)) patients, met the inclusion criteria. The operative time and harvested L. Ns number were higher in TOT versus TAT (standard mean difference (SMD) = 0.72 [95%CI 0.07; 1.37], P = 0.029 and SMD = 0.32 [95%CI 0.02; 0.62], P = 0.036 respectively) while less EBL in TOT versus TAT (SMD = -0.26 [-0.43; -0.09], P = 0.0018). All other outcomes showed no significant difference between both groups. Weighted mean values for TOT and TAT were 158.03 vs 144.97 min for OR time, 6.33 vs 5.16 for harvested LNs, and $5,919.05 vs $6,253.79 for the cost. Statistical significance in learning curve development was noticed ranging between 6 and 15 annual cases.

Trans-oral thyroidectomy is a safe and reliable technique with outcomes comparable to other endoscopic techniques. It provides better access to the central compartment with a more feasible LN dissection. Improvement in surgical outcomes is expected with growing learning curve and technique mastery.