Presidential Greeting - American Society for Laser Medicine and ...

#1
AMERICAN SOCIETY FOR
LASER MEDICINE AND SURGERY
EXPERIMENTAL AND
TRANSLATIONAL
RESEARCH (FORMERLY
BASIC SCIENCE)
SAFETY AND EFFICACY OF INFRARED NEURAL
STIMULATION IN HUMANS
Jonathan Cayce, Jonathon Wells,
Jonathan Malphrus, Chris Kao, Sharon Thomsen,
Noel Tulipan, Peter Konrad, Duco Jansen,
Anita Mahadevan-Jansen
Vanderbilt University Nashville, TN; Lockheed Martin Aculight,
Bothel, WA; University of Texas, Austin, TX
Background: Infrared neural stimulation (INS) is a new
approach for precise neural stimulation that involves pulsed
infrared laser energy through a non-contact interface, and has
been well characterized in animal models. However to study the
potential of this new technique in humans, safety and efficacy
must be demonstrated. A preclinical safety and efficacy evaluation
of INS was conducted in patients undergoing selective dorsal root
rhizotomy.
Study: Seven patients undergoing selective dorsal root rhizotomy
were recruited for this study. Each patient was monitored by
electromyogram (EMG) recordings in seven muscle groups on
each leg. Electrical stimulation was used to identify dorsal lumbar
spinal roots which exhibited spasticity. Spinal roots identified for
transection were optically stimulated on 2–3 sites per nerve with
our safest clinical laser parameters and muscle responses were
recorded and compared to electrically evoked potentials prior to
transection. After laser stimulation, a small portion of the spinal
root was analyzed histologically.
Results: Infrared neural stimulation evoked neuromuscular
responses through anterograde, trans-synaptic excitation of
alpha-motor neurons, and demonstrated higher spatial precision
than electrical stimulation and no stimulation artifact.
Stimulation threshold was identified as 0.53 J/cm 2 . Overall
efficacy of INS in this study was 63% (34/54) for non-damaging
radiant exposures between 0.53 and 1.00 J/cm 2 . Damage
threshold was identified at 1.09 J/cm 2 . The overall safety ratio was
calculated as 2.05:1 which is similar to the safety ratio identified
in animal studies.
ß 2011 Wiley-Liss, Inc.
American Society for Laser Medicine and Surgery Abstracts 1
ABSTRACTS
Conclusion: This study represents the first application of INS to
humans. The advantages of INS (spatial selectivity, contact-free
delivery, and no stimulation artifact) demonstrated in animal
studies were preserved. These results establish the efficacy
needed for future studies to investigate the utility of INS for
peripheral nerve mapping applications and functional
applications.
#2
TREATING TRACHEAL STENOSIS USING LOW
LEVEL LASER THERAPY: AS A POTENTIAL TOOL
IN AN EXPERIMENTAL STUDY IN RAT MODEL
Nathali Pinto, Claudia Silva, Raduan Hage,
Neila Garcia, Emilia Arisawa,
M. Cristina Chavantes,
UNIVAP, São José dos Campos, Brazil; USP, São Paulo, Brazil
Background: Tracheal stenosis (TS) is a life threat complication
after traumatic procedures in the central airways conduct. The
study’s aim was to evaluate Low Level Laser Therapy (LLLT)
preventing and treating tracheal stenosis in an experimental rat
model that could help treating patients.
Study: At first stage of this study, 45 Wistar rats were
anesthetized and induced tracheal stenosis by surgical
procedure, divided in three groups (15 animals each one): Group 1
(G1)—Control group, in which laser were simulated; Group 2
(G2)—LLLT 24 hours after tracheal stenosis induction (surgical)
procedure; Group 3 (G3)—LLLT 7 days after tracheal stenosis
induction procedure. After tricotomy, G2 and G3 were irradiated
w/LLLT transcutaneously onto cervical area (? ¼ 685 nm,
P ¼ 150 mW, dose ¼ 100 J/cm 2 , T ¼ 13 min). As a second stage,
five animals of each group were sacrificed and tracheal tissue’s
samples were collected for histomorphometry by counting
apoptotic cells, after 3 laser application: G1A, G2A, G3A—7
days after laser irradiation; G1B, G2B, G3B—14 days post-LLLT;
G1C, G2C, G3C—21 days after irradiation.
Results: G1A presented a more intense inflammatory infiltrate in
the submucosa area, while G2A showed more cells w/a thin
submucosa and G3A an infiltrate loose tissue. G1B exhibited less
inflammatory infiltrate while compared w/G2B and G3B. G2C
presented an intense inflammatory infiltrate, when compared w/
G1C e G3C, which showed straighter w/a large number of
fibroblast near lesion. In all animals observed dilated glands on
the lesion area w/reduced number in G2C.
Conclusion: The results suggest that laser phototherapy is an
effective method to modulate granulated tissue in acute
inflammatory process and avoiding widespread granuloma and
scar tissue. The importance of this study for patients w/TS, it is
Published online in Wiley Online Library
(wileyonlinelibrary.com).
DOI 10.1002/lsm.21034