The importance of cochlear nerve canal for the preoperative evaluation of children with high grade sensorineural hearing loss or deafness

Introduction:

Cochlear Implantation is the recommended therapy in children with high grade sensorineural hearing loss or deafness. However, an aplasia of cochlear nerve is a contraindication. So an adaequate preoperative imaging is necessary. In literature it is described a correlation between hypo- or aplasia of cochlear nerve and a stenosis of cochlear nerve canal (CNC).

Our aim was to correlate a hypo- or aplasia of cochlear nerve with diameter of cochlear nerve canal and internal auditory canal (IAC).

Methods:

We evaluated retrospectively the CT scan of all children with cochlear nerve hypo- or aplasia seen in MRI from 2014 to 2018. The diameter of CNC was assessed in axial CT scan and the height and the width of IAC in coronar reconstruction. The results were compared to the healthy sides.

Results:

There were 14 patients with hypo- or aplasia of cochlear nerve in MRI. In 6 children there was only the right side affected and in 4 children only the left side was affected. In 4 children we found a bilateral hypo- or aplasia of cochlear nerve. The diameter of CNC of the affected side (mean 1,09 mm) was significant smaller than the one of the healthy side (mean 2,32 mm). Also the height (mean 4,12 mm) and the width (mean 3,58 mm) of internal auditory canal of the affected side were significantly smaller than in the healthy side.

Conclusions:

CNC stenosis is a strong indicator for cochlear nerve deficiency. Also a small IAC can be a hint. In this patients there must be a special focus to the cochlear nerve with high resolution MRI.

Publication History

Publication Date:
23 April 2019 (online)