Elsevier

Surgical Neurology

Volume 53, Issue 4, April 2000, Pages 383-390
Surgical Neurology

Peripheral nerve
Radiosurgery for bilateral neurinomas associated with neurofibromatosis type 2

https://doi.org/10.1016/S0090-3019(00)00174-9Get rights and content

Abstract

OBJECTIVE

The clinical course of bilateral acoustic tumors associated with neurofibromatosis (NF2) is generally troublesome, and no definite treatment strategy has been established. Follow-up results of bilateral acoustic tumors after radiosurgery are reported herein.

METHODS

The current indications for radiosurgery are 1) a growing tumor less than 30 mm in mean diameter, 2) the ipsilateral ear has no serviceable hearing, and 3) there is risk of brain stem compression or brain stem dysfunction. Twenty cases of bilateral acoustic tumors were treated with the gamma knife, including 7 males and 13 females. The mean age was 38.2 years and the mean tumor size 24.4 mm. The tumors were treated with mean maximum and marginal doses of 26.8 Gy and 13.0 Gy, respectively. Among them, 12 patients had profound hearing loss in the ipsilateral (treated) ear, but the other 8 had serviceable hearing.

RESULTS

Tumors treated with radiosurgery showed central necrosis in 60% of the cases at 6 months and in 70% at 9 months after radiosurgery. Thereafter, the tumors often demonstrated slow regression. The rate of tumor shrinkage was 20% at 12 months, 35% at 24 months, and almost 60% at 36 months. At the last follow-up (mean 33.6 months), the tumors demonstrated shrinkage in 50% and tumor control in 100%. The contralateral tumors were stable in 12 (60%) and enlarged in 8 (40%). Preservation of serviceable hearing ipsilaterally was obtained in 33.3%. Deterioration of ipsilateral facial nerve function, either in the natural course or as a complication, occurred in 10%.

CONCLUSIONS

Because of good tumor control and tumor shrinkage as well as an acceptable complication rate, radiosurgery should be incorporated in the treatment strategy for bilateral acoustic tumors associated with NF2.

Section snippets

Current indications for radiosurgery

Of primary cerebellopontine angle tumors less than 30 mm in mean diameter, those that are growing constantly or progressively in a short period are indicated for radiosurgery. Usually larger tumors which may compress the brain stem in patients with no serviceable hearing are selected for the treatment. When serviceable hearing is preserved without any progression of neurological signs, simple observation is usually recommended. However, if hearing is lost bilaterally, both tumors are treated

Neurological outcome

There was no mortality during the mean follow-up period of 33.6 months (range, from 18 to 84 months). Neurological signs were stable in many cases, but some worsened because of progression of contralateral tumors. Ipsilateral hearing in the treated ear deteriorated further in eight cases, remained stable in three, and improved in one after some fluctuation. The other eight were already deaf at the time of radiosurgery and showed no change subsequently.

Contralateral hearing did not improve in

NF2 18-year-old male

Because of hearing deterioration, a right acoustic tumor was treated with the gamma knife with a marginal dose of 12.5 Gy. Although the treated tumor showed minor shrinkage at 30 months, the contralateral tumor apparently enlarged, causing facial palsy, and was treated with a second course of radiosurgery (12 Gy at the margin). Both hearing preservation and tumor control were achieved in this case (Figure 3 A,B).

NF2 49-year-old male

Radiosurgery to the right acoustic tumor (13.8 Gy at the margin) resulted in a

Tumor control

The majority of unilateral acoustic tumors have reportedly been controlled or reduced in size after radiosurgery 9, 11, 12, 15, 16. Noren et al [11] presented the results of 36 acoustic neurinoma patients who had radiosurgery with the gamma knife between 1975 and 1980, in which 92% tumor growth control was achieved in a mean follow-up of more than 12 years. These favorable results prompted us to use the same procedure for NF2 tumors.

Besides tumor control, there are a couple of important points

Conclusion

Radiosurgery can control the majority of acoustic tumors associated with NF2 for a long time, whereas 40% of contralateral (untreated) tumors continue to grow. Although hearing preservation is often difficult, preservation of facial nerve function is excellent compared with operative intervention. Therefore, radiosurgery should be incorporated in the treatment of bilateral acoustic tumors. Combined treatment with operation and radiosurgery is preferable in cases of large tumors.

References (20)

  • P. Bentivoglio et al.

    Surgical management of acoustic neuromas during the last five years

    Surg Neurol

    (1988)
  • D. Baldwin et al.

    Bilateral cerebellopontine angle tumors in neurofibromatosis type 2

    J Neurosurg

    (1991)
  • R. Fahlbusch et al.

    Preservation of hearing in large acoustic neurinomas following removal via suboccipital-lateral approach

    Acta Neurochir(Wien)

    (1998)
  • G. Gardner et al.

    Hearing preservation in unilateral acoustic neuroma surgery

    Ann Otol Rhino Laryngol

    (1988)
  • M.E. Glasscock et al.

    Management of bilateral acoustic tumors

    Laryngoscope

    (1989)
  • M.E. Glasscock et al.

    Preservation of hearing in surgery for acoustic neuromas

    J Neurosurg

    (1993)
  • W.B. Gormley et al.

    Acoustic neuromasresults of current surgical management

    Neurosurgery

    (1997)
  • J.W. House et al.

    Facial nerve grading system

    Otolaryngol Head Neck Surg

    (1985)
  • M.E. Linskey et al.

    Tumor control after stereotactic radiosurgery in neurofibromatosis patients with bilateral acoustic tumors

    Neurosurgery

    (1992)
  • R.L. Martuza et al.

    Neurofibromatosis 2 (bilateral acoustic neurofibromatosis)

    Lancet

    (1988)
There are more references available in the full text version of this article.

Cited by (67)

  • Familial Neoplastic Syndromes

    2022, Neurologic Clinics
  • Neurofibromatosis type 2 (NF2): Diagnosis and management

    2013, Handbook of Clinical Neurology
    Citation Excerpt :

    It successfully controls tumor growth in 66–100% of cases over a 5-year period (Linskey et al., 1992; Subach et al., 1999; Kida et al., 2000; Mathieu et al., 2007; Vachhani and Friedman, 2007; Meijer et al., 2008; Rowe et al., 2008; Phi et al., 2009). It also carries a 33–57% chance of preserving serviceable hearing over a 5-year period (Linskey et al., 1992; Subach et al., 1999; Kida et al., 2000; Mathieu et al., 2007; Meijer et al., 2008; Rowe et al., 2008; Phi et al., 2009). There is a 0–10% risk of significant permanent facial weakness although 10–17% of patients develop at least a transient weakness (Linskey et al., 1992; Kida et al., 2000; Mathieu et al., 2007; Meijer et al., 2008; Rowe et al., 2008).

  • Brain tumors associated with neurofibromatosis

    2011, Brain Tumors: An Encyclopedic Approach, Expert Consult - Online and Print
View all citing articles on Scopus
View full text