Influence of different approaches to the cerebellopontine angle on the function of the intermediate nerve

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Surgery in the cerebellopontine angle (CPA) is a standard procedure at many centers. Outcome is focused mainly on preservation of hearing and facial function postoperatively. The nonmotor part of the facial nerve, the intermediate nerve, is nearly neglected nowadays.


A retrospective study was designed, including a questionnaire that was sent to 178 patients who had undergone surgery between 2000 and 2004. Data were obtained in 156 cases. The questionnaire was divided into five parts assessing the presence of increased tearing, reduced tearing, salivation disturbances, increased nasal secretions, and abnormalities in taste. Finally, a self-assessment of patient symptoms was analyzed.


Postoperatively, 70 patients (45%) experienced crocodile tears, whereas 62 (40%) had dry eyes. Disturbances in taste were noted in six patients (4%) preoperatively and in 52 patients (33%) after surgery. Increased nasal secretion was noted in 68 patients (44%) postoperatively. An analysis of the correlation between the surgical approach used and disturbances in the intermediate nerve revealed a strong tendency to a higher rate of symptoms following the middle fossa approach (p = 0.071, chi-square test).


Data in this study demonstrate the clinical importance of nonmotor defects associated with CPA tumor removal. More than 50% of the patients in this study reported postoperative crocodile tears, dry eyes, nasal secretions, and/or taste disturbances. These sequelae may affect both short- and long-term postoperative quality of life to the same extent as deafness or transient facial paresis. The risk of injury seems to be higher after the middle fossa approach.

Abbreviation used in this paper:CPA = cerebellopontine angle.

Article Information

Address correspondence to: Tobias Stripf, M.D., Department of Ear-Nose-Throat, Klinikum Lahr-Ettenheim, Klostenstr. 19, 77933 Lahr, Germany. email:

© AANS, except where prohibited by US copyright law.



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    Bar graphs depicting self-assessment of the symptoms (complaints) caused by crocodile tears (left) and dry eyes (right). These symptoms were rated using a 10-point scale in which 1 indicates no symptoms and 10 indicates a strong disturbance in daily life. The x axis represents the 10-point scale for rating symptoms.


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