exam 1 material Flashcards
define absorbable suture
loss of tensile strength within 60-90 days
define non-absorbable suture
retains tensile strength >60 days
describe catgut/chromic gut
natural, completely absorbed in 2-3 weeks, high reactivity, chromium gut has chromium salt added to decrease reactivity, accelerated loss of tensile strength in infected wounds
name some uses for catgut/chromic gut
ligation of small vessels, rapidly healing tissue like mucosa, gingeva
describe monocryl
poligelecaprone 25, monofilament, synthetic, absorbable, 50% loss of tensile strength at 1 week
uses for monocryl
subcutaneous tissue, bladder
decribe vicryl
polygalactin 910, braided multifilament, synthetic, 50% tensile strength lost at 2-3 weeks
describe vicryl rapide
vicryl treated with irradiation that loses 50% strength at 5 days
when should you not use braided suture
infected wounds and delicate tissue
describe PDS
polydiaxanone suture, monofilament, synthetic, longest lasting of absorbables, 50% strength at 5-6 weeks
describe silk
natural, braided multifilament, high reactivity, 56% tensile strength at 12 weeks
describe prolene
polypropylene, monofilament, resistant to degradation, non-absorbable, low tissue reactivity
uses for prolene
tendons, ligaments, joint capsule, fascia, things you want to hold as long as possible
describe nylon
polyamide, usually monofilament, non-absorbable, 50% tensile strength at 12 weeks in acidic environment
most common feline cutaneous neoplasm that likes the ear
basal cell tumor
second most common feline cutaneous neoplasm
mast cell tumor
who can benefit from lateral ear canal resection? what does it acheive?
mildly affected patients with chronic ear infections, no stenosis, no boney changes. allows owner to get drops directly into the horizontal canal
who can benefit from vertical ear canal resection
when vertical ear canal is affected, but horizontal is clear. uncommon
what are the indications for total ear canal ablation
unresponsive chronic otitis externa, stenotic canals, failed previous resections, neoplasia, soft tissue extension of infection
what procedure must be paired with a total ear canal ablation
lateral bulla osteotomy
what is the goal of lateral bulla osteotomy? what is special about this procedure in cats?
improves drainage by removing secretory epithelium. cat bulla has 2 chambers and both must be treated
what procedure can be done for otitis media
TECA with LBO
how do you remove a nasopharyngeal polyp? bulla polyp?
traction and VBO, respectively
what procedure can be done for otitis interna
establish drainage usually with VBO. signs may or may not improve
where do large breeds vs brachycephalics usually get entropion
lateral canthus and medial canthus, respectively
who can benefit from temporary tacking for entropion
young animals or those with high anesthetic risk or spastic entropion
what is the most common surgical technique for permanent correction of entropion
hotz-celcus
what techniques may be combined for entropion involving the lateral canthus
holz-celcus and lateral wedge resection
what are indications for tarsorrhaphy
proptosis, lagophthalmos
how are proptosis and exophthalmus different
proptosis involves the eyelid entrapped behind the globe
exophthalmus has the globe pushed forward but no entrapment of lids
what are good prognostic indicators for vision following proptosis
menace, dazzle, consensual PLR
what are indications for enucleation with a proptosis case
ruptured globe, optic nerve avulsion, 3 or more extraocular muscles severed, complete hyphema
how are eye meds applied after tarsorraphy
medial canthus left open
what structures are removed in enucleation
globe, third eyelid and gland, conjunctiva, eyelid margins with meibomian glands
what are the indications for enucleation
-blind, painful eye
-ocular congenital defects resulting in chronic problems
-severe intraocular infections with significant globe destruction and source or systemic infection
-extensive intraocular tumors
-extensive intraocular inflammation that is uncontrolled and/or blind
-extensive trauma
-end-stage glaucoma
what are the two approaches to enucleation
subconjunctival - faster and less pain
transpalpebral - preferred for severe infection and large neoplasia
how much of the eyelid margin is removed to include the meibomian glands
5-8mm
what are the layers of closure for enucleation
orbital cone, subQ, skin
are eyelid tumors more aggressive in dogs or cats
cats. remove as soon as you see it or it will just get harder
dog eyelid tumors usually benign
what size tumors are able to be removed with wedge or house resection
involving <1/3 of lid length
what are the layers of a wedge resection or lateral canthotomy closure
tarsoconjunctival later and skin layer
use figure 8 for margin of skin closure
what is the normal size of the kidneys
2-2.5 x length of adjacent vertebrae
how much kidney function is lost in an azotemic patient
> 75%
why are we moving away from renal needle biopsy and nephrotomy
damage to kidney
why is pyelolithotomy preferred over nephrotomy
no occlusion of renal blood flow, no damage to renal parenchyma
but moving away from this as well
where should you ligate ureters during a nephrectomy
close to the bladder to decrease risk of infection of blind stump
why should ureter surgery be preformed by specialists
prone to leakage and stricture
what is neouteterocystotomy for
treatment of ectopic ureters
what is ureterotomy for
removal of calculi
what do you have to be careful of at the bladder trigone
ureters enter there, so avoid suturing this area
also, a lot of cell regeneration occurs there, so be careful in general
why do you have to be careful with the lateral ligaments of the bladder
ureters and umbilical arteries live there
what is the blood supply to the bladder
cranial vesicular artery in 50% of adult dogs (branch of umbilical artery), caudal vesicular artery (branch of urogenital a.), internal pudendal veins
what is the innervation to the bladder
hypogastric (sympathetic, retention), pelvic (parasympathetic, bladder emptying, pudendal (somatic, to external urethra sphincter)
must preserve nerves during surgery to preserve bladder function
how do you ensure no leakage after closing cystotomy
retrograde flush
how long for cystotomy site to heal
14-21 days
which direction should you flush when doing cystotomy for calculi
normograde and retrograde. finish with retrograde
what must you do after stone removal surgery
post-op radiographs! 15-20% have residual stones
how much of the bladder can be removed
75%
what are the preferred locations of urethrostomy in dogs and cats
scrotal in dogs, perineal in cats
should you place a catheter after perineal urethrostomy
no!
what is the quantitative definition of infection
10^5 bacterial organisms/gram
how long does it take a normal skin wound to heal
7-14 days
what percent of clean surgeries become contaminated? infected?
100% contaminated
2-5% infected
what are good go-to antibiotics for surgical site infection
cephalexin as 1st line
clavamox as 2nd line
define clean surgery
do not enter organs and no current infection
define clean contaminated surgery
enter hollow viscous organ without spillage
define contaminated surgery
spilled contents from hollow organ during surgery
define dirty surgery
enter surgery with active infection
ex: pyometra, cystotomy w/ UTI, pyoderma
what endocrinopathies increase risk of surgical site infection
hyperadrenocorticism, hypothyroidism
what are the most important factors in preventing surgical site infection
aseptic technique and maintaining healthy tissue
what NRC surgical classifications should you give perioperative antibiotics to?
clean-contaminated, contaminated, and dirty
not clean!
what are halsted’s principles
gentle tissue handling, meticulous control of hemorrhage, strict aseptic technique, preserve blood supply to tissues, eliminate dead space, appose tissues accurately with minimal tension
what NRC surgical classifications should you give therapeutic antibiotics to?
dirty (contaminated is controversial)
what are the key points to prophylactic antibiotics
target expected bacteria, ensure peak tissue concentration at the time of incision and throughout period of contamination, discontinue within 24 hours of surgery
T/F: aseptic scrubbing gets rid of all bacteria on the skin
F - 20% remains after scrub b/c bacteria live in hair follicles
what is the suggested perioperative antibiotic for most surgeries? when should it be given?
cefazolin 30-60 min prior to incision and redosed every 90 min
what is the rule of thumb for redosing antibiotics during surgery
time dependent antibiotics should be given every 2 half lives as long as incision is open
T/F: postoperative antibiotics are not indicated for prophylaxis
T - prophylactic antibiotics should be discontinued within 24 hours of surgery
exceptions - some implants where infection would be disastrous, devitalized tissue or dead space you can’t eliminate
what are the main cells active in the inflammatory phase of healing and what do they do
1 - platelets form blood clot and send signals to attract neutrophils
2 - neutrophils kill bacteria, debride necrotic tissue, and attract macrophages
3 - macrophages are the “master conductors”, day 3-5, phagocytosis
what are the classic signs of inflammation
heat, redness, swelling, loss of function
what are the gross characteristics of the inflammatory phase of healing? how long does this last?
cardinal signs of inflammation, purulent exudate, more exudate than wounds in proliferative phase, necrotic tissue, lasts 5-6 days
if necrotic skin is present, what stage of healing is the wound in
inflammatory
what cells are key to the proliferative phase of healing
fibroblasts
what are the gross characteristics of the proliferative phase of healing? when does this phase begin?
glanulation tissue (angiogenesis and collagen), epithelialization, contraction. starts around day 4
T/F: granulation tissue is prone to infction
false. HIGHLY resistant to infection
what cells are responsible for wound contraction
myofibroblasts
describe contraction vs contracture
contraction is a normal process that shrinks wounds
contracture is contraction that occurs over joints or natural orifices and is a pathologic process
what happens during the maturation phase of wound healing
closed wound strengthens, but never reaches the original strength
neutrophils need oxygen to work. below what level impairs their function
below 40 mmHg
does the center of a wound in the inflammatory phase have increased or decreased oxygen
decreased b/c larger gap between vessels
does the center of a wound in the proliferative phase have increased or decreased oxygen
granulation tissue has increased capillary density, so increased oxygen
how can the doctor control the phases of healing
debride to shorted the inflammatory phase
why does poor tissue oxygenation delay wound healing
neutrophils rely on oxygen, so increased risk of infection
collagen production requires oxygen, so shower proliferation
when you see a patient with a fresh wound, how do you decide to give antibiotics or not
contamination becomes infection in 6 hours. if you get to the wound before 6 hours, you can lavage and prevent infection. after 6 hours, should give antibiotics
what should you use to clean a wound
same solutions you use for surgical prep. not scrub! nothing with bubbles b/c hey inhibit fibroblasts
what is the best way to debride a wound
surgically!
what is autolytic debridement
done by the body and takes weeks
if in doubt, cut it out. but…
if it’s skin, leave it in.
(dead skin reveals itself after a few days. be more aggressive with debridement of subQ and muscle)
what is the most effective way to reduce bacterial numbers on the surface of a wound
lavage
saline ideal, but may use any IV fluid or tap water
may add chlorhexidine solution or povidone iodine solution
what is the ideal pressure for lavage
8 psi
what is primary wound closure
closing the wound the day you meet it
what is delayed primary wound closure
closing days later, but before granulation tissue
what is secondary wound closure
closing skin over granulation tissue
what is second intention healing
allowing the wound to heal by contraction and epithelialization
when should you not use primary closure
dirty/infected wounds, if waiting for new tissue to declare itself dead, burns, bite wounds, gunshot wounds, snake bites, too much tension
what are the goals of the primary bandage layer during the inflammatory phase
debridement and reduce bacterial contamination
what are the goals of the primary bandage layer during the proliferative phase
don’t disrupt new tissue, hold cells and cytokines in. want something non-adherent and occlusive
what general type of wound dressings are recommended
moist wound healing dressings
describe telfa + triple antibiotic in terms of debridement, antibacterial, non-adherent, and occlusive
no debridement
very antibacterial
is non-adherent
is occlusive
describe petroleum infused gauze in terms of debridement, antibacterial, non-adherent, and occlusive
no debridement
no antibacterial
is non-adherent
is occlusive
describe honey/sugar in terms of debridement, antibacterial, non-adherent, and occlusive
yes debridement
pretty antibacterial
is non-adherent
+/- occlusive
describe hydrogel in terms of debridement, antibacterial, non-adherent, and occlusive
no debridement
no antibacterial
pretty non-adherent
pretty occlusive
uncommonly used
describe polyurethane foam in terms of debridement, antibacterial, non-adherent, and occlusive
no debridement
no antibacterial
pretty non-adherent
is occlusive
basically bandaids/probably won’t stay on
describe calcium alginate in terms of debridement, antibacterial, non-adherent, and occlusive
yes debridement
no antibacterial
pretty non-adherent
is occlusive
which specific dressing is more desirable during the inflammatory phase
honey/sugar b/c has debridement and antibacterial properties
how often do you change bandages during the inflammatory phase? proliferative phase?
inflammatory - once per day for 2-5 days
proliferative - once you see the granulation tissue, slowly space out the changes. skip one day then if it looks good skip 2 days and so on. max of every 5 days
what are the down sides of second intention healing
takes a long time, alopecic, thin, shiny, fragile
when should topical antibiotics be used on wounds
generally indicated during inflammatory phase
not necessary and may be detrimental during proliferative phase
when can systemic antibiotics be used for wounds
indicated with infected tissue, controversial for contamination in inflammatory phase, not indicated for healthy wound during proliferative phase
how much fluid can be picked up with abdominocentesis
5-25 mL/kg
how do you determine if abdominal fluid is hemorrhagic or not
compare PCV/TS to serum. closer to serum level = more likely hemorrhage.
for DPL, >2-5% is diagnostic. do not need to compare with serum
what values are higher in free fluid than in serum? lower? what type of effusion is associated with each change?
higher - creatinine (urine), potassium (urine), bilirubin (bile), lactate (septic)
lower - glucose (septic)
how much fluid can be detected with diagnostic peritoneal lavage
1-5 mL/kg
how long does it take for a bilious effusion to show clinical signs? what are your first steps as a clinician?
4-6 weeks before detection
stabilize patient first. not emergent surgery
what are your steps as a clinician treating uroabdomen
drain with peritoneal catheter abdominocentesis and urinary catheter, stabilize patient, then surgical repair
what are your steps as a clinician treating hemoabdomen
find the source, conservative management (fluids, blood products, compressive bandages, stabilization, keep them calm, pain meds, monitor PCV), intervene surgically if medical management not working. fix them before DIC (petechiae, requiring too much blood, coagulation issues)
what are your steps as a clinician treating septic abdominal effusion
find the source (likely a ruptured hollow viscous organ), stabilize patient, EMERGENCY SURGERY
define true hernia vs false hernia
true hernia - contents contained within an anatomical hernial sac
false hernia - contents lack a hernial sac
what type of hernias are traumatic hernias
false hernia
what does incarcerated mean
stuck in a spot
what does strangulated mean
stuck and constricted, cutting off blood supply
T/F: traumatic hernias are emergent
false - most traumatic hernias are not emergent. stabilize and evaluate entire patient
how long can you postpone surgery on a traumatic hernia
3-5 days to allow declaration of nonviable tissues
when are hernias emergent?
penetrating wounds, incarcerated or strangulated tissues, other injuries warranting emergent intervention (severe hemorrhage, septic abdomen, pneumoperitoneum)
what is primary vs secondary peritonitis
primary has no inciting cause. secondary does
is prognosis better or worse with aseptic peritonitis
worse because no pathogen to treat
what type of peritonitis is most common
secondary generalized septic
what body system is the most likely to cause peritonitis
GIT
what clin path changes will be seen with peritonitis
marked neutrophilia (toxic), anemia, hypoproteinemia, hyper/hypoglycemia, electrolyte abnormalities (Na and Cl low with vomit, K low with anorexia), azotemia, liver enzyme elevation
what will be seen on abdominal radiographs with peritonitis
lack of serosal detail, ground glass appearance, gas behind diaphragm
with peritonitis, neutrophils will be high or low?
usually high but can be very very low with overwhelming inflammation
name some negative prognostic factors with peritonitis
refractory hypotension, cardiovascular collapse, respiratory distress, DIC, plasma lactate >2.5 mmol/L, ionized hypocalcemia, MODS
T/F: NSAIDs are sufficient for pain control with peritonitis
false. need opioids like methodone
what antibiotics should be used for peritonitis
cefoxitin and ampicillin sulbactam, empirical treatment usually accurate, but always good to culture
how should the small intestine be closed
full thickness, single later, appositional
what kind of hemostats are used to handle intestines
doyans
where should you cut for R&A
near a main artery branch for better blood supply to the wound edge. this may be farther from the spot you planned to cut
in addition to careful apposition of intestines during R&A, what else needs to be closed
the mesentery to prevent strangulation
what should be added to saline for intra-op peritoneal lavage
nothing! just warm saline
after peritonitis surgery, the abdomen flushes out well and mild inflammation is present. how should you close?
consider primary closure
after peritonitis surgery, the abdomen still has extensive fibrin tags, debris, necrosis, or severe peritoneal inflammation OR you don’t know the cause of the peritonitis. how should you close?
consider drainage options. use 2-3 drains because the omentum will clog the drains
are malignant tumors in young dogs usually more or less biologically aggressive than older dogs
more aggressive
T/F: palpation of regional lymph nodes can be used to determine if a cancer is metastatic
false - palpation alone can’t determine if metastatic. gives you a clue, but can feel normal and have metastatic dz
what is important to remember about diagnosing mast cell tumors
they love lymph nodes. aspirate nodes even if palpate normally
what is needed to grade a tumor
biopsy! not FNA
when should you do a biopsy instead of just FNA
when info about tumor type and grade would result in a change in choice of treatment option, extent of treatment (margins), or owner’s willingness to treat
what type of masses should not be FNA-ed
TCC b/c risk of seeding tumor
adrenal mass b/c sensitive area
what type of needle-core biopsy is used for soft tissues? bone?
soft tissue - tru-cut
bone - jamshidi
how can you improve diagnostic accuracy with needle-core biopsy
b/c it takes a small tissue sample, you should take multiple samples
what techniques are used for incisional biopsy
wedge or punch biopsy
T/F: oral tumor biopsy can be done with sedation and without local anesthetic
true. not usually painful
what needs to be considered when doing an incisional biopsy
need to be able to resect biopsy scar en bloc with tumor b/c contaminated with tumor cells
what needs to be considered before doing an excisional biopsy
resection does not have definitive margins, so it is diagnostic but may not be therapeutic. best to do FNA or needle core biopsy first!
what should you plan for when doing an excisional biospy
plan that biopsy tract will have to be surgically removed if incompletely excised. DO NOT TAKE FASCIAL PLANE. only consider in areas with sufficient soft tissue coverage. NOT DISTAL LIMBS
what factors are used in the WHO tumor stagins system
local tumor size/invasion, lymph node involvement, metastasis present
what is the most common mistake in tumor removal surgery
using too low of a surgical dose
what is radical resection
removal of a body part
ex: splenic hemangiosarc, limb amputation for OS
what is wide resection
lateral and deep surgical margins to remove the complete tumor burden (gross and microscopic). precise amount depends on tumor type and biological behavior
what lateral margins are recommended for wide margin resection
1 cm for most benign masses
2 cm for grade 1 or 2/low grade MCT
3 cm for soft tissue sarcomas
4-8 cm for intestinal tumors
5+ cm for feline injection site sarcomas
what deep margins are recommended for wide margin resection
minimum of 1 fascial plane. 2 planes for feline injection site sarcomas
what are natural tissue barriers? list examples
any tissue with resistance against tumor invasion
ex: muscle fascia, joint capsule, tendon, sheath, epineurium, cartilage, pleura, peritoneum
what is marginal resection
incomplete excision of a tumor with residual microscopic disease
what should be paired with marginal resection
adjuvant treatment for microscopic dz, like radiation
what are your options following unplanned marginal resection
- no tx
- staging resection of surgical wound - take a small sliver and repeat until you got it all
- wide resection of surgical wound - get it all in 1 revision
- adjuvant tx, like radiation
what is debulking/intralesional surgery
incomplete resection of tumor with residual gross disease. this is rarely acceptable treatment for cancer
what should be avoided for cancer surgeries
directly grasping tumor with instruments, penetrating tumor capsule, drains, flaps without confirmation of complete margins
what areas are considered contaminated during cancer surgery
biopsy tracts, subQ tissue undermined, donor sites and incisions for flaps, drain tracts
what is the most common type of sectioning for histopath
radial
what does histopath tell us about tumors
risk of local recurrence and mets, necessity of further tx, prognosis
