Table 1. Details of the systematic Review.

Author	No. of Patients	Approach	Functional gain
Sprinzl et al.2	12	Transmastoid retrosigmoid	25 db
Barbara et al.3	4	Transmastoid Retrosigmoid	36 db
Tsang et al.6	1	Transmastoid	24 db
Lassaletta et al.4	1	Retrosigmoid	43 db
Hassepass et al.8	2	Transmastoid	37 db