Table 4. Comparison between gasless and gas-inflated techniques.

Features		Gasless	Gas-inflated
Common features		Same patient position
		Single hidden axillary incision
		Same sentinel lymph node biopsy procedure
Differences
	Size of the initial incision	≥ 4 cm	Depends on the single port ring size; usually 2.5–3.5 cm
	Subcutaneous flap lifting	Self-retractor (Chung's)	Gas insufflation
	Working space area	Wide	Small space for port insertion
	Surgical field	Open	Closed
	Use of suction device	Easy	Difficult
	Use of a single-port device	No	Yes or no
	Nipple margin biopsy method	Manual	Robot-assisted
	Advantage	• Less fogginess because of open surgical field	• Possibly less bleeding because of CO2 gas insufflation
		• Steady elevation of subcutaneous flaps	• Less need for additional manipulations for setting the robotic arms
		• No air leak	• Dissection of subcutaneous flaps while maintaining dome shape of the breast
		• Surgeons with experience performing gasless thyroidectomy using a self-retractor are familiar with this technique
	Disadvantages	• Inevitable need to manipulate the position of the self-retractor to maintain a proper surgical view	• Visual disturbance by smoke
			• Potential risk of gas leak
			• Subcutaneous emphysema
			• Hypercapnia
			• Air embolism