Table 2.

Study characteristics for insertion speed of electrode array

	Mean age in years (range)	Gender (male/female)	Cochleostomy/round window	Electrode	Insertion length (mm)/time period (min)†	Insertion speed (mm/min, mean±SD)	Follow-up range (months)	Complete hearing preservation (%)
Gstoettner et al. [38]	46.13 (7.62-71.32)	2/7	2/7	MED-EL FlexEAS	18-22/3	Nil	6-17	44.4
Kuthubutheen et al. [39]	8 (1-15)	2/3	0/5	MED-EL FlexEAS	18/2	Nil	8-20	100
de Carvalho et al. [40]	47 (29-63)	5/1	1/5	MED-EL FlexEAS	18-24/3	Nil	14-18	16.7
Gotamco et al. [13]	18.03±22.07*	18/17	0/35	Nucleus Slim Straight CI422	25/nil	35.37±17.30	6	77.1

*This author recorded the mean age with standard deviation, ^†The authors of the first three papers only recorded the data of insertion length and time period without calculating for speed. SD: Standard deviation