VAS scruff surgery method

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No ancedotal stuff please.
Pet cancer treatment can cost ten thousand USA dollars. This forum is for people to tell us how they were able to obtain cancer treatment when they had no pet health insurance to cover the cost. Rabie Vaccine caused cancer often is paid for by the company that produced the vaccine even when not legally required to do so.

VAS scruff surgery method

Postby guest » Fri Oct 03, 2003 7:10 pm

The Use of a Latissimus Dorsi Muscle Flap for Scapular Reconstruction in a Cat Following Fibrosarcoma Excision

Sherman O. Canapp Jr, DVM, MS; F. A. Mann, DVM, MS, Diplomate ACVS, Diplomate ACVECC; Carolyn J. Henry, DVM, MS, Diplomate ACVIM (Oncology); Jimmy C. Lattimer, DVM, MS, Diplomate ACVR (Radiology, Radiation Oncology)
Journal of the American Animal Hospital Association
May 1, 2001




Keywords: Feline; Latissimus Dorsi Muscle Flap;Scapular Reconstruction;Fibrosarcoma 


A latissimus dorsi muscle flap was used to reconstruct a proximal scapular defect in a cat after excision of a fibrosarcoma that had recurred after eight surgeries, radiation therapy, and chemotherapy. To obtain appropriate surgical margins, infraspinatus and supraspinatus myectomy and scapular spinous ostectomy were performed. The latissimus dorsi muscle flap was rotated into the defect and anchored to four holes placed in the cranial border of the scapula. The cat showed no lameness at 6, 21, 42, and 147 days after surgery. The latissimus dorsi muscle flap was suc-cessful for proximal scapular reconstruction in this cat. J Am Anim Hosp Assoc 2001; 37: 283- 289.


Introduction
The awareness of vaccine-associated sarcomas in cats has been increas-ing. 1
Many epidemiological studies have reported an increase in the inci-dence
of feline soft-tissue sarcomas, mostly fibrosarcomas, at typical
vaccination sites. 2,3 The sites that have been reported with greatest fre-quency
are the dorsal cervical, interscapular, and femoral regions. 4-7 A
statistically significant association between feline leukemia virus (FeLV)
and rabies vaccinations and the development of fibrosarcomas at the
reported injection sites has been reported. 2 Other injectable products
including the feline rhinotracheitis-calici-panleukopenia (FVRCP) vac-cine 8,9
and lufenuron 10 have also been incriminated in the development of
sarcomas.
Vaccine-associated fibrosarcoma (VAFS) is typically a poorly encapsu-lated
neoplasm that grows by extension and spreads within fascial
planes. 11 Therefore, treatment of VAFS requires aggressive surgical exci-sion.
Preoperative radiation therapy to shrink the size of the tumor and
postoperative radiation therapy to treat residual microscopic disease have
been reported. 12-16 Additional adjuvant chemotherapy using mitox-antrone,
vincristine sulfate, cyclophosphamide, carboplatin, and doxoru-bicin
hydrochloride has been described. 11,17-22 The use of acemannan, an
immunostimulant, has also been reported as a valuable adjuvant therapy
for fibrosarcomas in cats. 5,23
The cat in this report was treated by wide surgical excision, which
included the infraspinatus and supraspinatus muscles and scapular spine,
followed by reconstruction using a latissimus dorsi muscle flap and post-operative
radiation therapy. This surgical procedure was performed after
eight previous surgeries, radiation therapy, and chemotherapy failed to
provide local control of the VAFS.


Case Report
A 12-year-old, spayed female, domestic longhair indoor cat was presented
to the University of Missouri-Columbia Veterinary Medical Teaching Hos-pital
(UMCVMTH) with a 2.5-year history of recurrent VAFS and a recent
mass located over the left scapular region. Prior to presentation, the cat had
eight surgeries for the treatment of VAFS located on both shoulders and
dorsal midline above the shoulders. The original tumor was 4
cm in diameter and located on the dorsal midline between
the scapulae; this mass was surgically removed by the pri-mary
care veterinarian 2.5 years prior to presentation to the
UMCVMTH. The mass was submitted for histopathology
and was identified as a fibrosarcoma. Ten months later, a
second mass was identified and removed from the same
location. A third mass was discovered on the right shoulder
and was surgically excised 2 months later and again 4
months later. Three months later, a mass was surgically
excised from the left shoulder region. Two more masses
were discovered and removed from the right shoulder 2
months and 4 months later. All tumors were submitted for
histopathology and were identified as fibrosarcomas with
incomplete margins. Two months later, another mass was
discovered over the right shoulder region, and the cat was
referred to a specialty surgery referral service for consulta-tion.
Following surgical excision, histopathological identifi-cation
revealed another fibrosarcoma, which according to the
pathologist was invading the muscle fascia of the triceps.
The surgeon then referred the cat to the UMCVTH for radia-tion
therapy and chemotherapy.
On physical examination at the UMCVMTH, the cat was
slightly overweight (4.12 kg) with a body condition score of
4 out of 5, 24 had shaved areas over the right shoulder, and
lumps (i. e., hemoclips) that were palpated under the skin.
Complete blood count (CBC), serum biochemistry profile,
and urine analysis were within reference ranges for the labo-ratory.
Feline leukemia virus and feline immunodeficiency
virus (FIV) tests were negative. Thoracic radiographs
showed no signs of metastatic disease. A computed tomogra-phy
(CT) scan was performed and revealed an area of con-trast a
and uptake in the right scapular region. Eighteen
treatments of radiation therapy (310 cGy per treatment, five
treatments per week using a 6-MV electron beam) and two
treatments of mitoxantrone (5 mg/ M 2 , intravenously [IV] q
21 days) chemotherapy were administered. Complications
from the treatments were mild and included a decreased
appetite, leukopenia (4.5 ´ 10 3 cells/ µL; reference range, 5.5
to 19.50 ´ 10 3 cells/ µL), and lymphopenia (0.72 ´ 10 3
cells/ µL; reference range, 1.50 to 7.0 ´ 10 3 cells/ µL).
One week after radiation therapy and chemotherapy, a
recheck examination was performed by the referring veteri-narian.
At that time, the cat still had a mild lymphopenia
(1.23 ´ 10 3 cells/ µL) and thrombocytopenia (91 ´ 10 3
cells/ µL; reference range, 160 to 600 ´ 10 3 cells/ µL). Three
weeks after radiation therapy, the cat was rechecked at the
UMCVMTH and appeared to be in good physical condition,
showing no signs of metastasis on thoracic radiographs and a
CBC and serum biochemistry within reference ranges. The
following week, a recheck CT scan showed evidence of
tumor growth over the left scapula, outside the previous radi-ation
treatment field. Surgery and follow-up radiation ther-apy
were scheduled for later that week.
On physical examination at the time of CT, a 2 ´ 3 ´ 2-
cm, firm, movable, nonpainful mass could be palpated over
the left scapula to approximately 3 cm from the border of the
scapula. No other abnormalities were discovered on physical
examination. A preoperative CBC revealed a mild lym-phopenia
(1.21 ´ 10 3 cells/ µL); serum biochemistry profile
and urine analysis were within reference ranges. The cat was
premedicated with buprenorphine b (0.005 mg/ kg body
weight, intramuscularly [IM]) and glycopyrrolate c (0.01
mg/ kg body weight, IM). General anesthesia was induced
with ketamine d (10 mg/ kg body weight, IV) and Valium e
(0.5 mg/ kg body weight, IV) and maintained with
isoflurane. f The cat was clipped from the left axillary region
dorsally to the dorsal border of the right scapula and from
just caudal to the occipital crest to the end of the thoracic
vertebrae. The cat was placed in sternal recumbency on a
rolled towel and aseptically prepared for surgery. A 2.5-cm
border around the mass was identified and marked using
electrosurgery [Figure 1]. After the skin incision, electro-surgery
was used to cut through subcutaneous (SC) tissues
and muscle layers. The latissimus dorsi muscle was bluntly
dissected and retracted caudoventrally with Gelpi retractors.
The teres major, infraspinatus, and supraspinatus muscles
were transected using electrosurgery [Figure 2]. Then the
infraspinatus and supraspinatus muscles were elevated off
the scapula using an Adson periosteal elevator. The scapular
spine was removed along with the infraspinatus and
supraspinatus muscles, using bone cutters and rongeurs. The
mass within the muscles, the scapular spine, and associated
cutaneous tissues was then removed [Figure 3], and cut sur-faces
were stained with India ink. The mass was placed in
10% neutral buffered formalin and submitted for histopatho-logical
evaluation. To reconstruct the scapular dead space,
the latissimus dorsi muscle was incised from its attachment
on the humerus and was elevated. An 18-gauge needle was
then used to create four holes in the cranial aspect of the
scapula through which the latissimus dorsi muscle flap was
anchored to the scapula with 3-0 polydioxanone sutures g
[Figure 4]. To cover the surface defect, the ventral skin mar-gin
was "walked" dorsally by placing simple interrupted
sutures, using 3-0 polydioxanone, g in the SC tissue and
underlying fascia. The dorsal skin margin was "walked" ven-
trally. Once adequate apposition of tissues was achieved, 4-0
polyglecaprone h was used in a simple interrupted SC pattern.
Skin closure was obtained using 35R stainless steel staples i
[Figure 5].
Following surgery, the cat showed no signs of complica-tions
from the reconstruction other than a mild (i. e., 2 out of
5) 25 lameness on the operated limb in the early postoperative
period. This lameness subsided over the 3 days of postopera-tive
hospitalization. The cat had normal range of motion on
flexion and extension, as well as abduction and adduction of
the operated shoulder, with minimal signs of discomfort. No
reconstruction-related problems (e. g., swelling, discharge, or
excessive inflammation) were noted during the 3-day post-operative
hospitalization. The cat was dismissed from the
UMCVMTH and scheduled for follow-up radiation therapy
at 3 weeks after surgery.
The histopathology report stated that the tumor was mor-phologically
consistent with fibrosarcoma. Present within
the subcutis and invading the subjacent skeletal muscle was a
moderately well-demarcated, nonencapsulated, multilobular,
expansile nodule composed of densely cellular, interwoven
bundles of spindle-shaped cells suspended in a collagenous
matrix. The cells had moderately anisokaryotic, oval,
coarsely reticular nuclei with one to three variably distinct
nucleoli and scant amounts of eosinophilic cytoplasm. There
were four to 10 mitoses per high-power field and interstitial
and perivascular aggregates of lymphocytes and plasma
cells. Neoplastic cells lined the deep margin in one section
and extended to the lateral inked margins in multiple sec-tions.
Neoplastic tissue lined but did not invade the
periosteal surface, and there was no evidence of infiltration
of the marrow spaces in the section examined.
Reevaluation 3 weeks following surgery showed no evi-dence
of reconstructive failure. The cat showed no signs of
lameness and had normal range of motion in the left thoracic
limb. No new masses could be palpated on physical exami-nation.
Radiation therapy was begun at that time and contin-ued
for 18 treatments (310 cGy per treatment using a 6-MV
electron beam). Following the 18th treatment (5,580 cGy
total dose) of radiation therapy, the cat was reevaluated for
signs of reconstructive failure or complications. On physical
examination, the cat had good range of motion in the left
shoulder, which was similar to that of the right shoulder. To
assess for muscular atrophy, measurements (of circumfer-ence)
were obtained using a standard tape measure. Mea-surements
of the right thoracic limb were 10.5 cm (proximal
humerus), 8.0 cm (distal humerus), and 6.0 cm (proximal
radius/ ulna). Measurements for the left (operated) thoracic
limb were 12.5 cm (proximal humerus), 8.5 cm (distal
humerus), and 8.0 cm (proximal radius/ ulna). Suture mate-rial
could be palpated beneath the skin at the level of the left
scapular border and between the shoulder blades. No new
masses were discovered on physical examination.
Reevaluation at 105 days following surgery showed no
evidence of reconstructive failure. The cat showed no signs
of lameness and had normal range of motion in the left tho-racic
limb. Once again to assess for muscular atrophy, mea-surements
were obtained using a standard tape measure.
Measurements of the right thoracic limb were 10.7 cm (prox-imal
humerus), 8.1 cm (distal humerus), and 6.0 cm (proxi-mal
radius/ ulna). Measurements of the left (operated)
thoracic limb were 12.6 cm (proximal humerus), 8.5 cm (dis-tal
humerus), and 8.1 cm (proximal radius/ ulna). No new
masses could be palpated on physical examination, nor were
any identified on CT scan with contrast.
No evidence of tumor recurrence was noted on CT scan
during the cat's recheck examination (136 days after surgery);
however, 160 days after surgery, a lump was noted by the
owner. The cat was once again presented to the UMCVMTH
for evaluation. This new mass was located at the craniodorsal
aspect of the left scapula and measured to be approximately
0.75 cm in diameter and 0.5 cm thick. Computed tomography
revealed that the mass had extensions into surrounding tis-sues.
The owners elected for an excisional biopsy but did not
wish to pursue further radiation therapy or aggressive surgical
procedures. At the time of surgery, the previously performed
latissimus dorsi muscle flap was identified and appeared to
have healed well to the scapula. Results of histopathology
identified the mass to be yet another fibrosarcoma with neo-plastic
cells extending beyond the surgical margins. It was
then recommended that acemannan therapy j (1 mg/ kg body
weight intraperitoneal injections weekly for 6 weeks) be initi-ated.
The owners elected to have the acemannan therapy initi-ated
by the referring veterinarian.


No complications or adverse reactions attributable to the
weekly intraperitoneal acemannan injections were noted.
Following 6 weeks of injections (270 days after surgery), a
new mass was discovered at the site of the previous exci-sional
biopsy. The owners decided not to pursue further diag-nostics
or treatments and elected euthanasia.


Discussion
The latissimus dorsi muscle is uniquely positioned for
extraordinary utility as a reconstructive tool. The latissimus
dorsi muscle has been used for scapular osteomyocutaneous
flaps, 26 myocutaneous flaps, 27 free parascapular flaps, 28 and
for dynamic cardiomyoplasty. 29 As described in this report,
the latissimus dorsi muscle was used to reconstruct and
replace scapular tissues.
The versatility of the latissimus dorsi muscle in transfer
as a muscle or myocutaneous flap unit permits closure of a
variety of difficult, complex wounds. Previous reports have
illustrated variations of flap design for reconstruction of the
shoulder and chest wall, 30 hand, 31 head and neck, 32 full-thickness
abdominal wall defects, 33 urinary bladder wall, 34
and extremities. 35 In these reports, the flap was based on
either the proximal or distal blood supply. The flap in these
reports was either transferred as a single unit or split longitu-dinally,
with or without overlying skin.
Although numerous procedures have been performed
using the latissimus dorsi muscle in human and veterinary
surgery, the muscle is quite different between humans and
animals. 36 In a study comparing the latissimus dorsi muscle
of humans to that of the canine, gross and histological studies
were carried out to identify anatomical and histochemical
properties that may be relevant to its use as a resource mus-cle.
The study found that in both human and canine latissimus
dorsii, three distinct muscle segments were observed that dif-fered
in direction of fibers, fiber characteristics, thickness,
and blood supply. The entire canine latissimus dorsi could be
separated into superficial and deep layers, whereas only the
anterolateral segment of human latissimus dorsi was sepa-rated
further by the neurovascular bundle. Histochemical
studies suggested significant differences between the ratios of
fast to slow fibers in the superior and anterolateral segments
of human muscle. 36 A comparative study in the feline species
has not been identified by the authors. However, the anatomi-cal
and experimental evaluation of the feline latissimus dorsi
muscle was performed to assess its potential use as a free
muscle flap. 37 The study showed the mean length and width
of the latissimus dorsi muscle was 19.0 and 5.4 cm, respec-tively.
The dominant vascular pedicle was the thoracodorsal
artery and vein. The average length and diameter of the thora-codorsal
artery was 2.7 cm and 0.6 mm, respectively. Minor
vascular pedicles were provided by branches of intercostal
arteries. Numerous choke anastomoses existed between the
two pedicle systems. Viability of muscle flaps based on sub-jective
evaluation, angiography, and histopathology was 66%
and 100% in the heterotrophic and orthotopic placements,
respectively; flap failure seemed to be caused by both arterial
and venous thromboses. 37
The latissimus dorsi muscle is a flat, triangular muscle
overlying the dorsal half of the lateral thoracic wall, and it is
the broadest of the skeletal muscles, with the exception of
the cutaneous trunci muscle. Its origin is the thoracolumbar
fascia from the spinous processes of the lumbar and the last
seven or eight thoracic vertebrae and a muscular attachment
to the last two or three ribs. Its insertion is the teres major
tuberosity of the humerus and the teres major tendon. The
action of the latissimus dorsi is to draw the ipsilateral limb
caudally and to flex the shoulder joint. Its innervation is via
the thoracodorsal nerve. 38 The thoracodorsal and lateral
arteries supply the dorsal and ventral portions of the latis-simus
dorsi muscle, respectively. Blood supply is also pro-vided
to the dorsal portion of the latissimus dorsi by the
intercostal arteries. 38
The cat in this report required a latissimus dorsi muscle
flap because of the need for aggressive surgical excision.
The fact that this was the cat's ninth surgery supports the
claim that complete surgical excision becomes more difficult
with increasing numbers of surgeries and that obtaining
complete margins at the initial surgery is crucial for cure.
Aggressive surgical intervention for the treatment of VAFS,
including excision of epaxial muscles, dorsal cervical verte-bral
processes, partial scapulectomy, hemipelvectomy, or
amputation, may be necessary to remove the entire tumor. 1
In this case, only the scapular spine was partially removed
along with the proximal scapular periosteum. On
histopathology there was no evidence of tumor involvement
within the periosteum.
Combining treatment modalities is indicated when single
modality treatment does not result in adequate tumor con-trol
or if the cosmetic or functional outcome of single
modality treatment is less than desirable. 39 In this case, pre-vious
surgical intervention was used with chemotherapy and
radiation therapy and proved to be unsuccessful in provid-ing
local control. Postoperative radiation therapy was again
used in this case for any microscopic tumor that may have
been left behind. The use of radiation therapy for the treat-ment
of VAFS is still controversial. Previous reports sug-gested
that VAFS was not radiosensitive, regardless of
radiation type used. 40,41 Those reports show that radiation
failure most commonly results in local recurrence within, or
at the edge of, the radiation field. 40-42 In another study, the
results of surgery and radiation therapy in 24 cats with
VAFS showed that only six (25%) cats had local recurrence,
with a median progression-free interval of 28 days. 13 In
some veterinary oncology centers, presurgical radiation ther-apy
is used to minimize the amount of viable tumor around
the palpable tumor. 12 Chemotherapy may be an important
adjuvant to radiation therapy for the control of distant tumor
spread. 43 The use of chemotherapy to treat measurable
tumors, using mitoxantrone or doxorubicin, has been contro-versial;
although not adequately tested, chemotherapy has
proven unsuccessful for local control according to most stud-ies. 14,17,39,43
However, while chemotherapy may not provide
local control for VAFS, it may help to delay or prevent
metastasis.


The use of acemannan, an immunostimulant derived from
aloe vera plant extract, has been reported to be a valuable
adjuvant therapy for fibrosarcomas in cats. 5,23,44 Studies
have shown positive results in cats with VAFS when com-bined
with other treatment modalities, including surgery and
radiation therapy. 5,23,44 It is believed that acemannan exerts
its antitumor activity through macrophage activation and the
release of tumor necrosis factor, interleukin-1, and inter-feron. 23,44
As supported by the literature, the cat in this
report showed no adverse effects from the use of
acemannan. 5,23,44 While acemannan therapy appears to be
safe, more studies are needed to determine its efficacy for
the treatment of VAFS.
As with any muscular flap, circulation and adjacent tissue
viability are crucial to success. Radiation therapy affects tis-sue
viability and circulation and may disrupt healing and
graft take. Reports have shown that skin flaps have failed
because of radiation injury to tissues within the flap itself. 45
It is well established that radiation therapy can affect normal
tissue viability through a late sequela of vascular injury. 46
This injury occurs as a result of depletion of "target" cells,
such as endothelial cells in blood vessels. 47 In this case, radi-ation
therapy was begun 3 weeks after the surgical excision
and reconstruction were performed. While it is well recog-nized
that neovascularization begins days after surgery, there
is no doubt that the flap may have been challenged postoper-atively
due to the radiation therapy. In addition, poor vascu-larization
will delay healing if the tissue is traumatized
months or years after irradiation. 48
In selected cases, partial scapulectomy may be indicated
for the surgical treatment of VAFS. 49 Partial scapulectomy
can preserve limb function and may be considered a viable
alternative to limb amputation. Extrapolating from the
results of this case, it can be anticipated that a latissimus
dorsi muscle flap may also be utilized to reconstruct the
proximal defect and add protection and support following
partial scapulectomy.
The prevalence of VAFS has been reported to be five in
every 10,000 vaccinated cats. 3 In vaccinated cats, the median
age for those with VAFS has been reported to be 8 years,
compared to 11 years for nonvaccination-site sarcomas. 3
Tumor development following vaccinations has been
reported to range from 3 months to 3 years, with the average
being 340 days. 2 According to one study, the median dis-ease-
free interval in five cats with fibrosarcoma tumor cells
at the margin of the resected specimens was 112 days, versus
700 days for 26 cats with negative tumor margins. 12 In that
study, no relationship was discovered between tumor vol-ume,
number of prior tumor excisions, concomitant use of
chemotherapy or various descriptors of the radiation therapy
technique, and disease-free interval. 12 In another, more
recent study of 45 cats that had one or more surgeries, or sur-gery
and radiation therapy for the treatment of soft-tissue
VAFS, there was an overall median tumor-free interval of 10
months and a median survival time of 11.5 months. 1 Age,
sex, breed, vaccination or FeLV status, tumor location, or
histopathological grade did not affect median tumor-free
interval (> 16 months versus 4 months) and survival time
(> 16 months versus 9 months) for those with incomplete
excisions. Radiation therapy did not seem to extend tumor-free
interval and survival times. 1 The cat in this study had
incomplete excisions following all eight surgeries, and at the
time of euthanasia was out 1,030 days since the first surgery.
According to one report, potential prognostic factors include
grade, resection margins, size, location, histopathological
type, and previous treatment, with grade and margins being
the most important. 39
Until the therapeutic benefits of chemotherapy and radia-tion
are more definitively documented for VAFS, surgical
excision remains the mainstay of treatment. Vaccine-associ-ated
fibrosarcoma is relatively slow growing and tends to
grow in a path of least resistance and invade surrounding tis-sues,
making a pseudocapsule of compressed cells. Because
the pseudocapsule marginal excision is of questionable bene-fit,
a minimum of 3-cm margins is recommended. 12,39 Mar-gins
should be inked, as in this case, prior to
histopathological analysis to aid in assessment of excision
completeness.


Conclusion
When aggressive surgery for VAFS is required and surgical
margins include portions of the scapula and its associated
musculature, a latissimus dorsi muscular flap should be con-sidered
for reconstruction. Based on the results of this case,
the use of a latissimus dorsi muscle flap represents a reliable
and effective technique to reconstruct large proximal scapu-lar
defects in cats. The latissimus dorsi flap can be translo-cated
without causing significant lameness and, based on
observations in this case, was apparently able to withstand
the effects of radiation.


a Hypaque 76 (diatrizoate meglumine and diatrizoate sodium injection
USP); Nycomed, Inc., Princeton, NJ b
Buprinex; Reckitt and Colman Pharmaceuticals Inc., Richmond, VA c
Robinul; A. H. Robbins Co., Richmond, VA d
Ketaset; Fort Dodge Animal Health, Fort Dodge, IA e
Diazepam; Schein Pharmaceutical Inc., Florham Park, NJ f
Isoflo; Abbott Laboratories, North Chicago, IL g
PDSII; Ethicon, Inc., Johnson and Johnson Co., Sommerville, NJ h
Monocryl; Ethicon, Inc., Johnson and Johnson Co., Sommerville, NJ i
Appose Unity; American Cyanamid Co., Wayne, NJ j
Acemannan; Carrington Laboratories, Inc., Erving, TX
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