Nervus Intermedius Outcomes after Vestibular Schwannoma Surgery and Radiosurgery: A Single Institution Experience

OBJECTIVEThe purpose of this prospective study was to evaluate the dysfunction of the nervus intermedius (NI) after vestibular schwannoma (VS) surgery. The authors present a clinically feasible method for this purpose.METHODSIn this prospective study, the authors included 30 patients who underwent surgery at the International Neuroscience Institute between May 2014 and February 2017 for resection of VS. The patients’ taste sensation was examined using taste strips. Lacrimation was tested using the Schirmer I test. The clinical evaluation was performed before surgery and repeated at 2 weeks and at 6 months after surgery as well as during the follow-up, which extended up to 2 years. The authors tested the correlation between the NI dysfunctions and the House-Brackmann grade of facial nerve palsy.RESULTSThe taste sensation was lost on the side of surgery in 2 patients (6.6%) and decreased in 4 patients (13.3%). The disturbance of taste sensation was not statistically correlated with dysfunctions of the motor portion of the facial nerve. The taste impairment resolved in 4 patients within 6 months, but 2 patients suffered from persistent loss of the taste sensation on the side of surgery during the follow-up. In 23 patients (76.6%), the baseline lacrimation was lower on the side of surgery, and it was significantly correlated with outcome for dysfunctions of the motor portion of the facial nerve. During the follow-up, baseline lacrimation improved in correlation with the improvement in the dysfunctions of the motor portion of the facial nerve. None of the patients reported change in salivation or nasal secretion.CONCLUSIONSThe NI can be affected after VS surgery. The disturbance of baseline lacrimal secretion was correlated with dysfunctions of the motor portion of the facial nerve. However, the disturbance of the taste sensation was not correlated with the grade of facial nerve palsy. Dysfunctions of the NI should be evaluated and separately reported while analyzing facial nerve outcome after VS surgery.

Download Full-text

Nervus intermedius dysfunction following Gamma Knife surgery for vestibular schwannoma

Journal of Neurosurgery ◽

10.3171/2012.10.jns12747 ◽

2013 ◽

Vol 118 (3) ◽

pp. 566-570 ◽

Cited By ~ 7

Author(s):

Seong-Hyun Park ◽

Kyu-Yup Lee ◽

Sung-Kyoo Hwang

Keyword(s):

Facial Nerve ◽

Gamma Knife ◽

Vestibular Schwannoma ◽

Primary Treatment ◽

Nasal Secretion ◽

Point Of View ◽

Gamma Knife Surgery ◽

Taste Disturbance ◽

Before And After ◽

Nervus Intermedius

Object The purpose of this study was to evaluate the function of the nervus intermedius, the nonmotor component of the facial nerve, following modern Gamma Knife surgery (GKS) for the treatment of vestibular schwannoma. Methods Sixty-five consecutive patients at our center underwent GKS as a primary treatment option for vestibular schwannoma between 2005 and 2010. The authors interviewed patients with a functional questionnaire to evaluate the function of the nervus intermedius before and after radiosurgery from their subjective point of view. Data from 50 patients treated using GKS for a unilateral vestibular schwannoma were obtained. Results Nine (18%) of 50 patients presented with at least one preradiosurgical disturbance of the nervus intermedius caused by the vestibular schwannoma itself, with dysfunctions of lacrimation, salivation, nasal secretion, and taste. Of the 41 patients without preradiosurgical disturbances, 9 (22%) experienced the onset of at least one new disturbance after GKS. Specifically for each dysfunction, of the 45 patients without a lacrimal disturbance before GKS, 5 (11.1%) had a new lacrimal disturbance after GKS. New onset of a salivary disturbance after GKS was reported in 3 (6.2%) of 48 patients. In 1 patient (2%), increased nasal secretion was noted 1 year after GKS. Five (10.6%) of 47 patients without a preradiosurgical taste disturbance experienced the symptom after GKS. No facial palsy developed in any patient before or after GKS. There was no significant correlation between postradiosurgical nervus intermedius dysfunction and tumor size, margin dose, or patient age. Conclusions The authors demonstrated that 22% of patients undergoing modern GKS for vestibular schwannoma experience various disturbances of nonmotor components of the facial nerve as a result of the radiosurgery. Through this study, we can provide useful information about the likelihood of certain postradiosurgical symptoms for vestibular schwannoma.

Download Full-text

Single-fraction vs. fractionated linac-based stereotactic radiosurgery for vestibular schwannoma: a single-institution study

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/s0360-3016(03)00444-9 ◽

2003 ◽

Vol 56 (5) ◽

pp. 1390-1396 ◽

Cited By ~ 145

Author(s):

O.W.M Meijer ◽

W.P Vandertop ◽

J.C Baayen ◽

B.J Slotman

Keyword(s):

Stereotactic Radiosurgery ◽

Vestibular Schwannoma ◽

Single Institution ◽

Single Fraction

Download Full-text

Nervus Intermedius Symptoms following Surgical or Radiation Therapy for Vestibular Schwannoma

Otolaryngology ◽

10.1177/0194599816655144 ◽

2016 ◽

Vol 155 (4) ◽

pp. 657-662 ◽

Cited By ~ 3

Author(s):

Kathryn Y. Noonan ◽

Cong Rang ◽

Katherine Callahan ◽

Nathan E. Simmons ◽

Kadir Erkmen ◽

...

Keyword(s):

Radiation Therapy ◽

Vestibular Schwannoma ◽

Nervus Intermedius

Download Full-text

Nervus intermedius function after vestibular schwannoma removal: Clinical features and pathophysiological mechanisms

The Laryngoscope ◽

10.1288/00005537-199508000-00007 ◽

1995 ◽

Vol 105 (8) ◽

pp. 809-813 ◽

Cited By ~ 32

Author(s):

Richard M. Irving ◽

Laura Viani ◽

David G. Hardy ◽

David M. Baguley ◽

David A. Moffat

Keyword(s):

Clinical Features ◽

Vestibular Schwannoma ◽

Pathophysiological Mechanisms ◽

Nervus Intermedius

Download Full-text

Pain-free and pain-controlled survival after sectioning the nervus intermedius in nervus intermedius neuralgia: a single-institution review

Journal of Neurosurgery ◽

10.3171/2018.3.jns172495 ◽

2019 ◽

Vol 131 (2) ◽

pp. 352-359 ◽

Cited By ~ 3

Author(s):

Katherine G. Holste ◽

Frances A. Hardaway ◽

Ahmed M. Raslan ◽

Kim J. Burchiel

Keyword(s):

Facial Pain ◽

Chart Review ◽

Clinical Presentation ◽

Neurovascular Compression ◽

Single Institution ◽

Free Survival ◽

Nervus Intermedius Neuralgia ◽

Nervus Intermedius ◽

Median Pain

OBJECTIVENervus intermedius neuralgia (NIN) or geniculate neuralgia is a rare facial pain condition consisting of sharp, lancinating pain deep in the ear and can occur alongside trigeminal neuralgia (TN). Studies on the clinical presentation, intraoperative findings, and ultimately postoperative outcomes are extremely limited. The aim of this study was to examine the clinical presentation and surgical findings, and determine pain-free survival after sectioning of the nervus intermedius (NI).METHODSThe authors conducted a retrospective chart review and survey of patients who were diagnosed with NIN at one institution and who underwent neurosurgical interventions. Pain-free survival was determined through chart review and phone interviews using a modified facial pain and quality of life questionnaire and represented as Kaplan-Meier curves.RESULTSThe authors found 15 patients with NIN who underwent microsurgical intervention performed by two surgeons from 2002 to 2016 at a single institution. Fourteen of these patients underwent sectioning of the NI, and 8 of 14 had concomitant TN. Five patients had visible neurovascular compression (NVC) of the NI by the anterior inferior cerebellar artery in most cases where NVC was found. The most common postoperative complaints were dizziness and vertigo, diplopia, ear fullness, tinnitus, and temporary facial nerve palsy. Thirteen of the 14 patients reportedly experienced pain relief immediately after surgery. The mean length of follow-up was 6.41 years (range 8 months to 14.5 years). Overall recurrence of any pain was 42% (6 of 14), and 4 patients (isolated NIN that received NI sectioning alone) reported their pain was the same or worse than before surgery at longest follow-up. The median pain-free survival was 4.82 years ± 14.85 months. The median pain-controlled survival was 6.22 years ± 15.78 months.CONCLUSIONSIn this retrospective review, sectioning of the NI produced no major complications, such as permanent facial weakness or deafness, and was effective for patients when performed in addition to other procedures. After sectioning of the NI, patients experienced 4.8 years pain free and experienced 6.2 years of less pain than before surgery. Alone, sectioning of the NI was not effective. The pathophysiology of NIN is not entirely understood. It appears that neurovascular compression plays only a minor role in the syndrome and there is a high degree of overlap with TN.

Download Full-text