Management of Acoustic
(Vestibular Schwannomas)File 1: Introduction to Acoustic Neuroma
G. OJEMANN, M.D. © Congress of Neurological Surgeons Honored
Originally Published Clinical Neurosurgery, Volume 40, Chapter
24, Pages 498-535, 1992
Used with permission of the Congress of Neurological Surgeons.
HTML Editor: Stephen B. Tatter, M.D.,
The information and reference materials contained herein are intended
solely to provide background information. They were written for an
audience of physicians. They are in no way intended to constitute
medical advise. For medical advise a physician must, of course, be
This chapter summarizes the consecutive
surgical treatment of 410 patients with unilateral acoustic neuromas
who were personally treated over a 14-year period from 1979 to 1992.
Patients with bilateral acoustic neuromas are not included. All
patients had a suboccipital approach. Although the approach was
suboccipital, the patients were evaluated and managed by a team.
The operations were done in corounction with an otologist surgeon
who exposed the internal auditory canal and dissected the tumor
in that area.
Over the years I have had the benefit
of working with otological surgeons Drs. William Montgomery, Joseph
B. Nadol, Jr., and Michael J. McKenna; neurosurgeon Dr. Robert Martuza;
otoneurologists Drs. Alfred Weiss and Stephen Parker; neurologist-neurophysiologist
Dr. Robert Levine; and neurophysiologist Dr. Stephen Ronner. All
have made important contributions in the management of the series
of patients I am reporting.
The chronological evolution of my experience
with acoustic neuromas has been summarized in a 1992 publication
(39). In the 1960s and 1970s there was a higher percentage of large
Our first goal was to improve the operative
morbidity and mortality and increase the preservation of facial
nerve function. This led to a plan utilizing the translabyrnthine
operations for smaller tumors and a combined two-stage operation
(translabrynthine and suboccipital approach) for larger tumors (44).
This plan was successful in achieving our initial goals. The advent
of computed tomography (CT) in 1973 was a major step in allowing
earlier and more precise diagnosis of acoustic neuromas. An early
publication summarized our experience with this study (7). Subsequently,
the entire subject of diagnosis of cerebellopontine angle tumors
was reviewed (28).
During the 1970s, as experience was
gained in the use of the operating microscope and in microsurgical
techniques, we found that for most tumors a one-stage suboccipital
operation gave as satisfactory a result as our previous two-stage
procedure. Occasionally, for large tumors a twostage suboccipital
approach was used. I used the sitting position and experience with
this approach was satisfactory, with a low operative mortality,
a high percentage of patients returning to normal activity, and
a significant preservation of facial nerve function (35, 36, 41).
In a few older patients I began to
use a modified supine position to avoid the risk of hypotension
(42). This position was more comfortable for the surgeon and more
physiological for the patient, the worry over air embolus was removed,
and there was excellent exposure of the tumor. Intermittent pulsation
of cerebrospinal fluid into the operative area did not present a
problem and tended to keep the nerves and vascular structures from
In 1979 1 shifted to this position
for almost all cerebellopontine angle tumors and experience with
this approach has been reported (39, 42, 43). This is why the series
reported in this chapter starts in 1979. At that time we were also
starting to save hearing in some patients.
In December 1991 the National Institutes
of Health held a Consensus Development Conference on acoustic neuroma
(9). It was estimated that between 2000 and 3000 new cases of unilateral
acoustic neuromas were diagnosed in the United States each year
(an incidence of about 1 per 100,000 per year). The panel concluded
that, "Treatment must be individualized and requires an
experienced, well-integrated, multidisciplinary team. The question
of whether and when to undertake treatment is complex. Currently,
the ideal treatment is the total excision of the tumor in a single
stage with preservation of neurological function" (9).
The need for research into the relative
benefits and risks of all management options was stressed. In this
report I present the microsurgical technique and the benefits and
risks of the suboccipital approach for surgical removal of these
tumors and suggest a management plan for patients with this tumor.