Arne Lindholm1, Ulf
Swensson1, Eje Collinder2*
*1 Mälaren Equine Hospital, Hälgesta 1,
S-193 91 Sigtuna, Sweden
2 Microbiology and Tumor Biology Centre,
Karolinska Institutet, von Eulers väg 5, S-171 77 Stockholm, Sweden
ABSTRACT
CO2 laser has been used for five years at Mälaren
Equine Hospital, as an alternative treatment of some equine diseases. The
application of CO2 laser has been studied for evaluation of its
appropriateness for treatment of the equine diseases sarcoids, lameness in
fetlock joints or pulmonary haemorrhage. During the last five years, above
100 equine sarcoids have been removed by laser surgery (CO2 laser) and so
far resulting in significantly few recurrences compared with results from
usual excision surgery. In one study, acute traumatic arthritis in fetlock
joints was treated three times every second day with defocalised CO2
laser. The therapeutic effectiveness of CO2 laser in this study was better
than that of the customary therapy with betamethasone plus hyaluronan.
During one year, chronic pulmonary bleeders, namely exercise induced
pulmonary haemorrhage, has been treated with defocalised CO2 laser. Six
racehorses have been treated once daily during five days. Until now, three
of these horses have subsequently been successfully racing and no symptoms
of pulmonary haemorrhage have been observed.
These studies indicate
that CO2 laser might be an appropriate therapy on sarcoids and traumatic
arthritis, and probably also on exercise induced pulmonary haemorrhage.
Other treatments for this pulmonary disease are few.
INTRODUCTION
At Mälaren Equine Hospital, the last five years CO2
laser has been used as an alternative for treatment of some equine
diseases. For treatment of the equine diseases sarcoids, traumatic
arthritis in fetlock joints and exercise induced pulmonary haemorrhage CO2
laser has been used as described below. Clinical effects of these laser
treatments are briefly reported and if they might be appropriate modes of
treatment.
CO2 LASER
The authors have used a CO2 laser, 25 W, with a scanning
device, focalised or defocalised. The laser consists of a CO2 emitter with
a wavelength of 10,600 nm. A visible Helium-Neon laser radiation
(Wavelength 632.8 nm) superimposed on the CO2 emitter showing the area
covered by the laser beam. With the scanning device the beam of the guide
light HeNe and the CO2 laser can be transformed from the shape of a point
into a line. The user has to adjust and set the length of this “line”, as
well as the height of the movement, to cover the area of the tissue to be
treated. At the scanner there is a timer that automatically switches off
the radiation after the desired treatment time set by the user. In that
way, the scanning device automatically directs an equal amount of
radiation over the actual tissue. To achieve the desired amount of
radiation to the tissue per cm2, the user has to combine the following
parameters: Watt, time and tissue area. This scanner has the advantage of
being able to shed the radiation equally over the treated tissue in a
controlled manner to avoid the risk of side effects, such as burning, or
uncontrolled over/underexposure.
SARCOIDS
Equine sarcoids are
defined as unique, benign, non-metastasising but locally aggressive,
fibroblastic skin tumours (1), but they have no relation to human
sarcoidosis (2). The etiology of sarcoids has been contentious, but both
epidemiology and clinical behaviour of sarcoids strongly suggest the
involvement of an infectious agent (both retroviruses and papilloma
viruses have been implicated), although numerous attempts of isolation
have met little reward. However, equine sarcoids are found world-wide and
comprise the most common tumour in equine practise. The lesions appear
solitary or multiple, sometimes at sites of previous wounds. Although
rarely pruritic or painful, the lesions have a reputation for being
notorious difficult to treat due to locally aggressive, infiltrative
growth, high rates of recurrence after excision, large size, multiple
lesions and/or localisation to sites compromising excision, like eyelids
(3). The clinical manifestations of sarcoids are very variable. Solitary
or multiple lesions can appear at any part of the body surface and growth
rate and size may vary from small, inactive nodules to large masses of
aggressive growing, secondary infected flesh, giving the impression of
infiltrating surrounding tissues. After the initial appearance, individual
sarcoids may retain static for years or fluctuate in size over a period of
time and occasionally regress, sometimes only to reappear later at
previous or new sites. Laser surgery has sometimes been used for treatment
of sarcoids (4).
The major problem associated with sarcoids in equine
practise is the high incidence of recurrence after surgery. The recurrence
rate of approximately 50 % within three years after excision, of which the
majority recurred within six months, has been reported (5). Because of
this great recurrence after treatment with classical excision surgery we
have used laser surgery to remove 105 sarcoids during the last four
years.
These sarcoids were situated on penis, preputium eyelids, close
to eyes and on the nose, back, neck and different other places in the
skin. The horses were tranquilised intramuscularly with detomidine, 0.5 ml
Domosedan® and butorphanol, 0.8 ml Torbugesic®. Thereafter the skin was
clipped and sterilised with alcohol after which a local anaesthesia was
performed with 2% Carbocain®
Method for laser incision: The body of
the tumours were lifted up and an articulated arm with a 125 mm handpiece
at 25 Watts in a continuous mode focalised to a spot light focus (0.2 mm
spot size) was used back and forth until the tumour was separated from its
base. After removal of the sarcoid the area site for the sarcoid and the
skin edges were sealed until complete haemostasis was achieved by heat.
This heat was achieved by using the handpiece laser defocalised, at a
distance from the tissue area that the spot size was 2-3 mm and
coagulation took place. The skin wound was left open without sutures. The
wound was then kept clean, but no other treatment was performed
afterward.
Out of cases older than 6 moths, 25 % recurred and 75 % are
recovered. This material comprises mostly Swedish Warmbloods, mean age of
the horses was seven years and mean time for the wound after surgery to be
healed was ten days.
This result might indicate for further use of CO2
laser on sarcoids. Especially when sarcoids are localised on troublesome
sites for surgery with a scalpel, such as eyelids, in the skin close to
the eye-globe, penis, preputium etc. - laser surgery should be the most
successful method.
TRAUMATIC ARTHRITIS
CO2 laser for treating traumatic arthritis in
equine fetlock joints, and their clinical effects, has been evaluated
together with a comparison with the effects of cortisone treatment. Before
treatment, the horses were placed in a stock under sedation with
detomidine intramuscularly, 0.5 ml Domosedan® and butorphanol, 0.8 ml
Torbugesic®. Our aim was to estimate the clinical effects of the customary
intra-articular treatment with betamethasone (?M) plus hyaluronan (HA) and
of CO2 laser, as modes of treatment upon traumatic arthritis in fetlock
joints. The intra-articular dose of ?M was 2 ml Celeston® bifas®; 6 mg/ml,
the intra-articular dose of HA was 2 ml Hylartil© vet 10 mg/ml, and the
dose of the defocalised CO2 laser was 60 Joule/cm2 tissue surface; six
minutes per treatment lateral and medial. The joints were treated three
times: on day 1, 3 and 5. No pain or side effects from that laser
treatment were noticed.
Altogether, 144 horses constituted the
experimental animals and 285 fetlock joints with acute traumatic arthritis
were included; 114 fetlock joints were treated with CO2 laser and 171
treated intra-articularly with ?M + HA, which is the most common treatment
of traumatic arthritis in fetlock joints. Thereafter, the lameness of the
treated fetlock joints was re-evaluated 3-4 weeks after treatment. The
recovered fetlock joints: 92 of the fetlock joints treated with CO2 laser,
80.7 %, and 116 of the fetlock joints treated with ?M + HA, 67.8 %. This
amount of recovered joints after CO2 laser-treatment was significantly
higher than that after ?M + HA – treatment.
The authors assume that
CO2 laser might be the best treatment for synovitis in horses,
particularly acute traumatic arthritis in fetlock joints. The mechanism
behind this effect of the laser treatment, however, remains relatively
unknown.
EXERCISE INDUCED PULMONARY HAEMORRHAGE
Until today, we have treated
six race horses (4 Thoroughbreds, 2 Standardbreds) diseased of so-called
exercise induced pulmonary haemorrhage with defocalised CO2 laser. Before
treatment, the horses were placed in a stock under sedation with
detomidine intramuscularly, 0.5 ml Domosedan® and butorphanol, 0.8 ml
Torbugesic®. The dose of defocalised CO2 laser was 60 Joule/ cm2 skin
surface over each lung, corresponding to about 20 minutes/side. The lungs
were treated once daily at 5 consecutive days. This group of horses
treated for exercise induced pulmonary haemorrhage is interesting, but too
small to draw finite conclusion from. However, three of these horses have
after laser treatment started and won race, and this result may encourage
us and/or others to use CO2 laser upon this pulmonary disease, as other
treatments are rare. In all horses of this group, the number of
macrophages decreased post treatment.
REFERENCES
1. Jackson, C.
(1936) The incidence and pathology of tumors of domestic animals in South
Africa. Ondertepoort J. Vet. Sci. Anim. Ind. 6: 16; 241-248; 375-385;
429.
2. Stannard, A.A. and Pulley LT (1978) Tumors of the skin and soft
tissues. In: Tumors in Domestic Animals, 2nd ed, JE Moulton (ed),
University of California Press, Berkley, Los angeles, pp: 16-74.
3.
Broström, H. (1995) Equine sarcoids. A clinical, epidemiological and
immunological study. Thesis, Swedish University of Agricultural Sciences,
Uppsala, Sweden.
4. Palmer, S.E. (1989) Carbon dioxide laser removal
of a verrucous sarcoid from the ear of a horse. JAVMA 195;
1125-1126.
5. Ragland, W.L. (1970) Equine sarcoid. Equine Vet. J. 2,
2-11.
*Correspondence author:
Eje Collinder
Microbiology and Tumor
Biology Centre
Karolinska Institutet
von Eulers väg 5
S-171 77
Stockholm
Sweden
