Nervus Intermedius Symptoms following Surgical or Radiation Therapy for Vestibular Schwannoma.
This study compares the functional outcomes of nevus intermedius impairment following surgery, radiation, or observation for the treatment of vestibular schwannoma.



Retrospective cohort study.



Tertiary care medical center.



We retrospectively examined 141 charts of patients with a vestibular schwannoma seen in the Dartmouth-Hitchcock Acoustic Neuroma Clinic between 2012 and 2014. Seventy-one patients underwent intervention (including radiation) as their primary treatment, and 70 were treated with observation. As part of routine care, patients were interviewed at clinic visits and with a questionnaire assessing nervus intermedius impairment.



At presentation, 25 patients (19%) reported nervus intermedius impairment. Most common disturbances were xerophthalmia (dry eyes, 13%) and dysgeusia (taste alteration, 7.6%). Postintervention, 35 patients (53%) had ≥1 symptoms of nervus intermedius dysfunction, which is increased in comparison with patients in the observation group (17 patients, 26.5%, P < .05). Twelve intervention patients had symptoms resolve postoperatively, making no long-term difference between the observation and intervention groups (P = .20). Motor function of the facial nerve postoperatively is correlated with nervus intermedius symptoms. Surgical approaches were compared with radiation therapy, and no significant difference in nervus intermedius outcomes was found.



This study demonstrates the clinical importance of monitoring nervus intermedius symptoms, since a high percentage of all patients undergoing intervention will be symptomatic during management. Patients with motor dysfunction are at a higher risk of developing nervus intermedius sequelae and need close follow-up. Although impairment is common, many symptoms will improve over time with no long-term difference between intervention patients and those under observation.
Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA Kathryn.y.noonan@hitchcock.org.
Kathryn Y
KY
Noonan
Northwestern Medical Center, Evanston, Illinois, USA.
Cong
C
Rang
Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA.
Katherine
K
Callahan
Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA.
Nathan E
NE
Simmons
Temple University, Philadelphia, Pennsylvania, USA.
Kadir
K
Erkmen
Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA.
James E
JE
Saunders
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005154:Facial Nerve / Q000528:radiation effects*; D020220:Facial Nerve Injuries / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000532:radiotherapy* / Q000601:surgery*; D019370:Observation; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
Wrisberg nerve; acoustic; facial nerve; intermediate nerve; nervus intermedius; neuroma surgery; radiosurgery; vestibular schwannoma