The Diagnosis of Acoustic Neuromas

1973 ◽  
Vol 6 (2) ◽  
pp. 391-400 ◽  
Author(s):  
Galdino E. Valvassori
Keyword(s):  
Acoustic Neuromas

Human Neurofibromas in Co-Culture with Mouse Neurons

1982 ◽  
Vol 40 ◽  
pp. 194-195
Author(s):  
R.L. Martuza ◽  
T. Liszczak ◽  
A. Okun ◽  
T-Y Wang
Keyword(s):  
Schwann Cell ◽  
Schwann Cells ◽  
Genetic Disorder ◽  
Cranial Nerves ◽  
Sympathetic Nerves ◽  
Acoustic Neuromas ◽  
Spinal Roots ◽  
Neural Crest Origin ◽  
Multiple Abnormalities ◽  
Other Neoplasms

Neurofibromatosis (NF) is an autosomal dominant genetic disorder with a prevalence of 1/3,000 births. The NF mutation causes multiple abnormalities of various cells of neural crest origin. Schwann cell tumors (neurofibromas, acoustic neuromas) are the most common feature of neurofibromatosis although meningiomas, gliomas, and other neoplasms may be seen. The schwann cell tumors commonly develop from the schwann cells associated with sensory or sympathetic nerves or their ganglia. Schwann cell tumors on ventral spinal roots or motor cranial nerves are much less common. Since the sensory neuron membrane is known to contain a mitogenic factor for schwann cells, we have postulated that neurofibromatosis may be due to an abnormal interaction between the nerve and the schwann cell and that this interaction may be hormonally modulated. To test this possibility a system has been developed in which an enriched schwannoma cell culture can be obtained and co-cultured with pure neurons.

Lesions Mimicking Small Acoustic Neuromas

2016 ◽  
Vol 77 (S 02) ◽  
Author(s):  
Matthias Scheich ◽  
Rudolf Hagen ◽  
Desiree Ehrmann-Müller ◽  
Hans-Ullrich Völker
Keyword(s):  
Acoustic Neuromas

Long-Term Radiologic Follow-Up of Tumor Remnants after Subtotal Resection of Acoustic Neuromas

Skull Base ◽  
2007 ◽  
Vol 16 (S 1) ◽  
Author(s):  
Fred Barker ◽  
Steven Kalkanis ◽  
Michael McKenna ◽  
Dennis Poe ◽  
Joseph Nadol ◽  
...  
Keyword(s):  
Subtotal Resection ◽  
Acoustic Neuromas

Microsurgical Treatment of Small Acoustic Neuromas

Skull Base ◽  
2007 ◽  
Vol 17 (S 2) ◽  
Author(s):  
Bharat Guthikonda ◽  
Myles Pensak ◽  
Ravi Samy ◽  
Philip Theodosopoulos
Keyword(s):  
Microsurgical Treatment ◽  
Acoustic Neuromas

Staged Resection of Large Acoustic Neuromas: Indications, Surgical Results, Facial Nerve Outcomes, and Complications

Skull Base ◽  
2007 ◽  
Vol 17 (S 2) ◽  
Author(s):  
James Liu ◽  
Ilman Kim ◽  
Matthew Hunt ◽  
Sean McMenomey ◽  
Johnny Delashaw, Jr.
Keyword(s):  
Facial Nerve ◽  
Surgical Results ◽  
Acoustic Neuromas

Stereotactic radiotherapy for the treatment of acoustic neuromas

2004 ◽  
Vol 101 (Supplement3) ◽  
pp. 362-372 ◽  
Author(s):  
Michael T. Selch ◽  
Alessandro Pedroso ◽  
Steve P. Lee ◽  
Timothy D. Solberg ◽  
Nzhde Agazaryan ◽  
...  
Keyword(s):  
Stereotactic Radiotherapy ◽  
Tumor Size ◽  
Cranial Nerve ◽  
Target Volume ◽  
Tumor Control ◽  
Content Type ◽  
Seventh Cranial Nerve ◽  
Acoustic Neuromas ◽  
Fine Print

Object. The authors sought to assess the safety and efficacy of stereotactic radiotherapy when using a linear accelerator equipped with a micromultileaf collimator for the treatment of patients with acoustic neuromas. Methods. Fifty patients harboring acoustic neuromas were treated with stereotactic radiotherapy between September 1997 and June 2003. Two patients were lost to follow-up review. Patient age ranged from 20 to 76 years (median 59 years), and none had neurofibromatosis. Forty-two patients had useful hearing prior to stereotactic radiotherapy. The fifth and seventh cranial nerve functions were normal in 44 and 46 patients, respectively. Tumor volume ranged from 0.3 to 19.25 ml (median 2.51 ml). The largest tumor dimension varied from 0.6 to 4 cm (median 2.2 cm). Treatment planning in all patients included computerized tomography and magnetic resonance image fusion and beam shaping by using a micromultileaf collimator. The planning target volume included the contrast-enhancing tumor mass and a margin of normal tissue varying from 1 to 3 mm (median 2 mm). All tumors were treated with 6-MV photons and received 54 Gy prescribed at the 90% isodose line encompassing the planning target volume. A sustained increase greater than 2 mm in any tumor dimension was defined as local relapse. The follow-up duration varied from 6 to 74 months (median 36 months). The local tumor control rate in the 48 patients available for follow up was 100%. Central tumor hypodensity occurred in 32 patients (67%) at a median of 6 months following stereotactic radiotherapy. In 12 patients (25%), tumor size increased 1 to 2 mm at a median of 6 months following stereotactic radiotherapy. Increased tumor size in six of these patients was transient. In 13 patients (27%), tumor size decreased 1 to 14 mm at a median of 6 months after treatment. Useful hearing was preserved in 39 patients (93%). New facial numbness occurred in one patient (2.2%) with normal fifth cranial nerve function prior to stereotactic radiotherapy. New facial palsy occurred in one patient (2.1%) with normal seventh cranial nerve function prior to treatment. No patient's pretreatment dysfunction of the fifth or seventh cranial nerve worsened after stereotactic radiotherapy. Tinnitus improved in six patients and worsened in two. Conclusions. Stereotactic radiotherapy using field shaping for the treatment of acoustic neuromas achieves high rates of tumor control and preservation of useful hearing. The technique produces low rates of damage to the fifth and seventh cranial nerves. Long-term follow-up studies are necessary to confirm these findings.

Diagnostic Implications of Stimulus Polarity Effects on the Auditory Brainstem Response

2002 ◽  
Vol 13 (02) ◽  
pp. 072-082 ◽  
Author(s):  
Cynthia G. Fowler ◽  
Christopher D. Bauch ◽  
Wayne O. Olsen
Keyword(s):  
Mayo Clinic ◽  
Auditory Brainstem Response ◽  
Auditory Brainstem ◽  
The Other ◽  
Intersubject Variability ◽  
Acoustic Neuromas ◽  
Full Complement ◽  
Brainstem Response ◽  
Polarity Effects ◽  
Click Polarity

The purpose of this study was to determine whether clicks presented in rarefaction or condensation modes produce more accurate diaghostic information. Subjects were 20 consecutive patients who were seen at the Mayo Clinic for unilateral acoustic neuromas. The nontumor ear served as a control to minimize intersubject variability in the latencies. A standard audio logic evaluation was followed by an auditory brainstem response (ABR) test for which the stimuli were rarefaction and condensation clicks. Responses were analyzed for the presence of waves I, III, and V; absolute latencies of waves I, III, and V; interpeak intervals I–III, III–V, and I–V; and interaurallatency difference for wave V. The results indicated that measures from both polarities were similar in this set of patients and that neither click polarity provided diagnostic advantages over the other. Recommendations are to collect ABRs to both click polarities individually to obtain the full complement of waves on which to base the diagnostic impression.

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