Management of vestibular schwannomas current trends

Introduction:

Management of vestibular schwannomas has undergone lots of changes during the past decade. Review of published literature exemplifies this fact. Various currently available management modalities to treat this condition are:

1. Observation

2. Stereotactic radiosurgery

3. Microsurgery

Among these three modalities stereotactic radiosurgery is evincing keen interest because of the precision of the procedure and lesser incidence of side effects. Advances in imaging technology have enabled early diagnosis of these lesions. About a decade back the sensitivity of imaging techniques used to identify lesions measuring 30 mm. Recent imaging modalities are accurate enough to identify even lesions measuring less than 10 mm. A stage has reached when surgeons are managing more intracanalicular lesions than ever before.

The current management modality of these tumors focusses on:

Preservation of hearing

Preservation of facial nerve functions.

Observation / Watchful waiting: This modality is preferred in managing patients with small asymptomatic / minimally symptomatic intracanalicular tumors. Since tumor doubling time of these lesions is prolonged (1-2 mm / year) this method warrants a trial. Advantages of this method are preservation of hearing and facial nerve function in these patients. Studies have also revealed that growth rates between intracanalicular and extracanalicular tumors are not significantly different. It is ideal to perform imaging at least twice a year within the first year of diagnosis and once a year from there on.

Positive features that could warrant this management modality include:

1. Excellent speech discrimination scores

2. Growth rate of less than 2.5 mm / year

Microscopic surgery:

This is indicated for small intracanalicular lesions with vestibular symptoms. Amount of tumor growth also is one important factor that could force the hands of a surgeon. Growth rate of more than 3mm / year is an indication for surgical intervention. Hearing can be conserved by using retrosigmoid / middle cranial fossa approach.

Stereotactic radiosurgery:

This is indicated in residual lesions after microscopic excision or rapidly enlarging canalicular lesions. Advantages of radiosurgery include:

1. Hearing preservation

2. Conservation of facial nerve function