HEAD & NECK SURGERY - Stanford University School of Medicine

S T ANFORD U NIVERSITY D EPARTMENT OF O TOLARYNGOLOGY – HEAD & N ECK S URGERY
R ESEARCH P ROGRAMS
Figure 2 – Generation of the Nyquist plot, an objective
representation of normal vocal fold vibration.
form of high-resolution MRI imaging for
the detection of early invasive cancer of
the vocal cords (Figure 3). High-resolution
MRI scanning may allow images of
the larynx at 8 to 10 times the resolution
of standard MRI, and a clinical trial is currently
underway to determine its role in
predicting invasion of the cartilage by
cancer.
Earlier detection of advanced disease
may afford higher rates of laryngeal conservation
in the future.
Figure 3 – High-resolution MRI of the human larynx.
14
CLINICAL RESEARCH IN
OTOLOGY-NEUROTOLOGY
Nikolas H. Blevins and Robert K. Jackler
Planned Subtotal Resection and
Stereotactic Radiotherapy for Acoustic
Neuroma
The advent of stereotactic radiosurgery
has provided the clinician with a nonsurgical
option to control the growth of
acoustic tumors. With the development
of the Cyberknife linear accelerator system,
Stanford has long been a pioneer in
the non-surgical management of skull
base disease. Despite considerable experience
with small acoustic tumors, the
role of radiosurgery into the treatment
of large tumors remains to be fully
defined. The potentially synergistic effect
of combined microsurgical resection and
stereotactic radiotherapy could offer
effective new options to individuals who
remain at most risk given conventional
treatment.
The Stanford Department of Otolaryngology
in collaboration with the departments
of Neurosurgery and Radiation
Oncology, is leading a prospective multicenter
trial to assess the efficacy of managing
large acoustic neuromas (over 3
cm) with a combination of planned
subtotal resection followed by stereotactic
radiosurgery. Patients enrolled in the
protocol will undergo planned subtotal
resection avoiding potentially injurious
dissection of the facial nerve from the
tumor capsule. Patients will be followed
with serial MRI scans, and will receive
stereotactic radiation to the tumor remnant
if growth is detected.
The prospective nature of this study will
provide valuable data towards establishing
optimal treatment of advanced disease,
while minimizing the risk of postoperative
facial nerve dysfunction.
Planned subtotal resection of an acoustic neuroma
The Stanford Cyberknife.
The Use of Stacked ABR for the
Assessment of Hearing Preservation in
Acoustic Neuroma Resection
Patients with small acoustic neuromas
and good hearing are faced with a
choice of treatment options. Whether
they choose to undergo microsurgical
resection or stereotactic radiotherapy
(such as with Cyberknife) can be largely
influenced by the likelihood of hearing
preservation. The short-term rates of
hearing preservation with stereotactic
radiation are excellent, but given the persistence
of tumor and possible long-term
neurovascular changes, hearing levels
may deteriorate with time. Microsurgery
in contrast, often places additional risks
to hearing in the short term. However,
the expectation for maintaining hearing
that is present post-operatively is quite
favorable. Unfortunately, there is a current
lack of preoperative predictors of
which patients are more likely to retain
hearing through a surgical procedure.
The Stanford Departments of Otolaryngology
and Audiology are engaged in a
prospective clinical trial to assess innovative
of electrophysiologic testing to predict
the success of hearing-preservation
attempts. The study applies highly sensitive
auditory brainstem response techniques
(“stacked ABR”) that may be an
accurate predictor of the potential for an
involved cochlear nerve to withstand surgical
manipulation and tumor extraction.
The development of such non-invasive
preoperative predictors will substantively
assist with patient counseling and
treatment planning in patients with
acoustic neuromas. Given this additional
information, patients and their clinicians
may make better-informed decisions
about the pursuit of treatment options.