Surgery

A

C

D

What is a hernia? What are the three components of a hernia? (LA)

Protrusion of an organ or tissue through a natural or traumatic opening

• Components of a hernia

  • Defect

  • Content

  • Sac

Internal vs external hernias? (LA)

• Internal hernia

  • A hernia  not involving the abdominal wall

  • Epiploic, mesenteric, diaphragmatic et al.

• External hernia

  • The hernia content protrudes through a defect in the abdominal wall

  • Umbilical, scrotal, ventral, prepubic

True/false: a one finger hernia has a worse prognosis due to bowel moving in and secreting fluid (LA)

true

How should you treat an umbilical hernia? (LA)

Conservative Treatment

• Manual reduction

  • Useful for small hernias (less than 2 fingers) with no infection

  • Owner is instructed to examine and reduce the hernia at once or twice daily

  • Hernia ring may close spontaneously

• Corset

  • Work well in calves but not in foals

  • Small hernias can be the most dangerous

• Ring scarification

  • Injection or topical application of irritant drugs

• Strangulation

  • Devices

    • Elastator bands

    • Strangulating sutures

    • Hernia clamps

    • ONLY tiny hernias, otherwise can cause infection!!

  • Induce necrosis and sloughing of the hernia sac

• Reserved for hernias that are <5cm, reducible and non-infected

Surgical Treatment

• Indications

  • Large reducible hernias

  • Small hernias which have not responded to conservative therapy

  • Mandatory for treatment of strangulated or irreducible umbilical hernias

• The optimal age for repair is 3-4 months

• Preferably after weaning

• Umbilical herniorrhaphy (open vs closed)

• Umbilical resection

  • Indications = Umbilical infection

    • Pain, swelling, heat, purulent drainage on physical examination

    • Thickened, enlarged vessels (often with a hypoechoic center) on ultrasound examination

    • Patent urachus

    • If unresponsive to conservative therapy

3 umbilical remnants in the horse (LA)

• Umbilical vein

  • Round ligament of the liver

• Umbilical arteries

  • Round ligaments of the bladder

• Urachus

What is a ventral hernia and its etiology? (LA)

• A hernia in the abdominal wall at a site other than a natural opening

• Etiology

  • Blunt trauma (kicks, thrusts)

  • Iatrogenic (incisional hernia)

• The size of the defect and content vary considerably

• Strangulation of contents is unusual

Timing of repair for ventral hernia (LA)

• Rarely do an immediate repair - unless strangulated

• Traumatic hernias

  • Immediate repair (within 8-12hrs of injury)

    • Required for strangulated hernia

    • Tissue damage and severe inflammatory reaction are unfavorable for healing

  • Delayed repair (after 6-8 weeks)

    • Inflammatory reaction has subsided and fibrosis at the site gives better purchase for sutures

  • Postoperative hernias

    • Repair is delayed until inflammation subsides and any infection in the wound is brought under control

Method of repair for a ventral hernia (LA)

• Depends on location and size of hernia

• Re-closure of fascial and muscle layers

• Mesh herniorrhaphy

  • Large defects

  • Hernias with a weak hernial ring.

  • Use of synthetic mesh to either bridge an abdominal wall defect or to reinforce closure of a defect with sutures

  • Mesh may be placed deep to the body wall, superficial to the body or both deep to and superficial to the body wall

  • Mesh should be used only under strict aseptic conditions. Infection of the implant and formation of draining tracts is a serious complication

What is a prepubic tendon rupture and how do you diagnose it? (LA)

Prepubic tendon rupture

• Usually occurs late term mares. Particularly draft breeds

• Occurs rarely in cattle

• Rupture may be either unilateral or bilateral

• Usually preceded by severe ventral edema (differentiate from physiological edema common in late term mares)

• May be avulsion of ventral musculature

Prepubic tendon rupture - diagnosis

• Imminent rupture

  • Caudoventral abdominal edema

  • Pain on palpation of the caudoventral abdomen

  • Reluctance to move the rear limbs

• Following rupture

  • Sagging of the caudoventral abdomen

  • Disruption of the prepubic tendon on rectal palpation or ultrasound

  • Rear limb discomfort

How do you treat a prepubic tendon rupture? (LA)

• Impending rupture

  • Strict rest

  • Control of edema

  • Consider induced parturition

• Following rupture

  • Prognosis for salvage of the mare is grave

  • Strict rest

  • Induced, attending foaling

  • Or terminal c-section

  • Successful

Describe a direct vs an indirect inguinal herniation. (LA)

• Indirect = Intestine within vaginal tunic - adjacent to the testicle

  • Only so much intestine can fit in here

  • Vaginal tunic can rupture and become a direct hernia

  • Much more common

  • Content enters the inguinal canal via an abnormally large vaginal ring. The superficial and deep rings are normall.

• Direct = direct defect in the peritoneum, intestine slipped down adjacent to the vaginal tunic =  allows for more intestine to fit. 

  • content passes through the body wall (internal oblique muscle) and into the inguinal canal

  • hernia content is outside the common tonic

Do umbilical hernias usually have signs in small animals?

No

True/false: umbilical hernias are not risky because there is no chance of bowel entrapment (small animals)

false!!!!!! bowel entrapment is a risk!!!!

If an umbilical hernia is soft, non-painful, and reducible, how should you approach treatment? What if it is firm, painful and associated with GI signs? (small animals)

Soft, non painful, reducible =

1. small ring - close at neutering if desired

2. large ring - have owner monitor - close at neutering.

Firm, painful, associated with GI signs = surgical emergency.

true/false: inguinal hernias are mostly seen in males (small animals)

false - 70-90% are females.

Estrus and pregnancy are risk factors

L > R

(LA) Congential inguinal hernias are almost always _______, however acquired hernias may be either indirect or direct

indirect

How do you treat a congenital scrotal hernia? (LA)

Congenital scrotal hernia - conservative treatment

• Indicated for small reducible hernias in foals

• Hernia is reduced at least twice daily. Close observation is mandatory to identify possible strangulation

• Most congenital hernias in foals will respond to this therapy within several weeks

• Heriation in newborn foals is associated with an abnormally large vaginal ring. Temporary herniation is relatively common since testicular descent is late (last trimester of gestation) and the testis is relatively large

  • Recommend primary closure castration when gelded

Congenital scrotal hernia - surgical treatment

• Indications

  • Piglet and lambs

  • Foals

    • Colic due to the hernia

    • Exceptionally large hernias

    • Hernias that fail to respond to conservative therapy in timely fashion (3-4 months)

• Technique = castration with a twist and tack (twist the spermatic cord about its long axis to obliterate the cavity of the vaginal tunics and anchored it to the superficial inguinal ring using a transfixing ligature)only works on indirect hernias

True/false: you diagnose a stallion with an acquired inguinal/scrotal hernia. Treatment is rest and monitor.

NOOOOOOOO!!! It is a surgical emergency!!!!!

• Herniorrhaphy with castration

• Resection of damaged intestine or

• Laparoscopy (it may be possible to save the testicle if it is not compromised)

C

F

a 7/o male intact lab undergoes negative abdominal exploratory. Locoregional anesthesia not provided. Which opioid is best for pain management post op?

1. hydromorphone

2. buprenorphine

3. tramadol

4. butorphanol

hydromorphone

Function of the skin

• Protection

• Regulation

• Sensation

• Immunosurveillance

Scalpel vs electrocautery vs laser

• Longer healing time using laser vs. scalpel

• Reduced inflammation and bleeding when using electrocautery than with scalpel

Phases of Wound Healing

• Inflammation

• Tissue formation

• Remodeling

Describe the inflammation phase of wound healing

• Begins with platelets - activate and degranulate

  • Potent callout for neutrophils

• Neutrophil migration into wound bed peak at ~48hrs

  • Clean up agent (using NETS)

    • Looking for bacteria

    • Looking for ROS

  • Releases cytokines to set up stage for next phase

• Associated with swelling, redness, pain, heat

• Calls in macrophages - inflammatory to regenerative

Describe the tissue formation phase of wound healing

• Defined by macrophages (architects)

• Tissue formation (beginning of granulation tissue) 3-5 days dog, 5-6 days cat

  • Angiogenesis

  • Fibroblasts

• Clinical implication

  • Angiogenesis = immature leaky vessels (clear fluid in wound - normal)

  • Fresh granulation bed = exudative wound

  • Wound fluid rich in cytokines and MMPs - can inhibit healing = frequent dressing changes

    • Want fluid to leave (keep wound dry) = cytokine soup = inhibits regeneration

  • Good granulation tissue = healthy wound, OK to close

• Absence of granulation tissue in an open wound by 3-5 days (dogs) or 5-6 days (cats) signals a problem

  • Excess necrotic tissue

  • Contamination

  • Poor perfusion

  • Infection

  • Poor patient health

Describe a clean wound

• Surgical wound made under conditions of asepsis

• ABX prophylaxis not required unless implants used/extended surgical time/break in asepsis

Describe a contaminated wound

• Open traumatic wound

• Wounds made with a major break in sterile technique eg spillage of GI contents

• ABX prophylaxis required

Describe a dirty/infected wound

• >10^5 bacteria per gram of tissue

• Clinically exhibits heat, pain, swelling, redness, and discharge

• Therapeutic abx required

• Purulent necrotic wound

• Established peritonitis

Descibe a clean contaminated wound

• Surgical wound under conditions of asepsis but during which respiratory, urinary, or alimentary tract is entered (this is on purpose)

• Abx prophylaxis required

How does wound classification dictate wound management

• Heavy contamination/established infection/necrotic tissue = period of open wound management prior to closure

• Minimally contaminated traumatic wound or clean surgical wound = can be closed immediately

Describe primary closure

• One stage surgical closure

• Success depends on

  • Good perfusion to wound bed and skin margins

  • Minimal exudate production

  • Ability to remove all foreign material from wound

  • Absence of any necrotic tissue

  • Minimal to no tension

• Restricted to clean, clean-contaminated and contaminated wounds where contamination can be managed

• If dehisces - you got it wrong

Describe delayed primary closure

• Wound is managed open until a healthy granulation bed has formed, then close

• Best method where

  • Wound viability is questionable

  • Limited tissue available if prematurely closed wound dehisces

Describe second intention healing

Wound managed open as it granulates, contracts, and epithelializes all the way to closure without surgical intervention

Patient factors that inhibit wound healing

• Diabetes mellitus - impaired macrophage function

• HAC

• FIV

• Steroids

• Chemotherapy

• Severe anemia

• Poor nutritional status

• Hypotension under GA

• Hypothermia under GA

• Length of time under GA

• Species = cats

Wound factors that inhibit wound healing

• Tension = poor found perfusion

• High mobility area

• Pressure points = point of elbow/hock

• Radiation site

• Highly productive wound

• Excessive suture material in wound bed

• Presence of foreign material or necrotic tissue

Active vs passive drains. Function? When to place? Complications?

• Active

  • Jackson pratt

  • Active suction

• Passive

  • Penrose

  • Relies on gravity

• Functions

  • Eliminate dead space

  • Remove excess fluid-macrophages don't swim

• When to place

  • At the time of surgical closure of healthy wounds where

    • Wound is exudative

    • When dead space can’t be effectively managed by other means (suture/bandages)

    • To manage a deep abscess (closed suction only)

• Complications

  • Foreign material in wound increases risk of dehiscence

  • potential for ascending bacterial infection

  • Potential for drain material to be accidentally retained in wound

Drain principles

• Drain should not exist through the primary incision

• For passive drains, exit point must be gravitationally dependent and amenable to aseptic management with bandaging

• In the case of the abdominal cavity, closed suction drains ONLY

• Avoid in oncologic surgery - they expand the surgical margin

• Use the smallest number of drains and size of drain possible

• Use active closed suction drains instead of passive where possible

• Remove the drain as soon as possible - typically 2-4 days

Penrose drains

• Only exist through ONE hole

• Don’t make exit point too tight

• No sutures anchoring drain in wound bed

• Don't - suture at both ends, fenestrate the drain, make the exit hole too small.

Basic wound management

1. wear gloves

2. apply sterile water/soluble gel to wound surface

3. clip local area generously

4. lavage

5. ± debride

6. ± forage exposed bony surfaces

7. wound ready for closure.

Difference between primary closure, delayed primary closure, and second intention healing

1. Primary closure - minimal contamination, no necrotic tissue remaining and little likelihood of late onset necrosis

2. Delayed primary closure - manage open until good granulation coverage signals a healthy wound - then close

3. Second intention healing - managed with bandaging until the wound contracts and epithelialized without surgical intervention - can be lengthy - typically reserved for small wounds or wounds with minimal available soft tissues to mobilize

Incidence of bandage injuries? Generally traced to what?

• Bandage injuries

  • 60% incidence - of which 40% mild, 10% moderate, 10% severe

  • Can generally be traced to:

    • Insufficient padding

    • Too long between bandage changes

    • Bandage allowed to become wet

    • Bandage too tight

    • Poor bandage technique

      • Toes left out

      • No allowance made for flexion of limb

    • Poor owner communication

    • Poor staff training or inappropriate task delegation

  • Ehmer sling - closed reduction of hip luxation. 50% incidence of soft tissue wounds, 18% severe

How to prevent bandage injuries

• Written and verbal owner instructions

• Written instructions signed by owner to acknowledge receipt

  • Restricted activity

  • Warning re potential for serious bandage injury

  • Instruct to re-present patient immediately if:

    • Bandage wet, soiled, or slipping

    • Patient chewing at bandage

    • Patient becomes lame or stops using limb

  • If can’t re-present immediately then remove bandage

Indications and goals of bandaging.

• Indications to bandage

  • To support/protect a surgical incision

  • To manage a contaminated traumatic wound until wound is suitable for delayed primary closure

  • To manage a wound to closure by second intention

• Goals

  • To maintain an optimal environment for wound healing

    • Mechanically stable

    • moist

    • Protected

What do bandages consist of?

• Contact layer

• Absorptive layer

• (splint)

• Outer layer

Bandages - Contact layer for minimal/moderately contaminated wound prior to granulation tissue formation

• Alginate dressings

• Soluble - forms a gel trapping contaminants and bacteria

• Non-traumatic

• Moist

Bandages - Contact layer for heavily contaminated/necrotic/infected wound prior to granulation tissue formation

• Honey soaked sterile gauze

• Saline soaked lap sponges - “wet to dry”

• Sugar under lap sponges

• But these dressings are traumatic and termed DEBRIDEMENT DRESSINGS

Bandages - contact layers for granulating wound

• Post formation of granulation tissue

  • Non-debridement dressing

  • hydrocolloid/hydrogel under non-adherent semi-occlusive dressing

  • Foam dressings eg mepilex

  • NOT telfa alone on an open wound - trying to avoid any dessication

    • Only useful for healing surgical incisions in first 6-12hr window

    • No absorption, fall off easily

Bandage change frequency

• Debridement dressing - Q6-24hrs depending on fluid production

• Non-debridement dressing (alginate/foam type Q2-4days)

• Change as soon as there is any strike through

• Adjust frequency of changes to wound appearance and the state of the contact layer at each change

• If $$$ is a problem - better to improvise with materials than compromise on frequency

How does honey work on wounds?

• Hyperosmolarity results in bacterial kill

• Antioxidants

  • Protects against free radicals

  • Chelates iron, preventing bacterial growth

  • Peroxidases contained in unpasteurized honey

• Acidity

  • pH 3.6-5.0

  • Promotes healing

  • Antimicrobial

• Viscous barrier to wound invasion

• Cheap and readily available

• No drug resistance recorded

• local honey

Purpose of absorptive layer when bandaging

• Absorbs exudate

• Distributes bandage pressure

• $$$

True/false: superficial wound cultures are usually helpful when determining wound management

False - All open wounds contain bacteria, often a mix of species

• Superficial wound cultures are rarely indicated/helpful

Systemic abx for open chronic wound management are indicated when:

• Acute traumatic wound

• The patient has systemic signs of infection

• There is evidence of

  • Abscess

  • Cellulitis >1cm beyond wound margin (get culture from here)

  • Osteomyelitis

  • Lymphangitis

• Not needed if:

  • Mild, local inflammation

  • Healthy granulation tissue covering full wound bed

Common causes of delayed second intention healing

• Excess bandage pressure-insufficient padding

• Excess time between bandage changes

• traumatic/desiccating contact layer

• Excess tension - poor availability of surrounding tissues limits contraction

• Poor wound vascularity - bony surfaces

Halsted’s principles

• Strict aseptic technique

• Gentle tissue handling

• Meticulous hemostasis

• Preservation of blood supply

• Obliteration of dead space

• Accurate apposition of tissue planes minimization of tension on tissues

True/false: Undermining and walking sutures will close 90% of wounds that are NOT on a distal extremity

true

Which part of the body would you use a free graft for? Describe the biology of a free graft.

Distal limb

How to close a wound under tension?

• Walking sutures

  • Tension suture

  • Dermis to fascia

  • PDS

  • Do not compromise blood supply, however skin sutures under tension will compromise blood supply and cause necrosis

• Multiple releasing incisions for distal extremity wounds

• Single releasing incision allowing skin to be mobilized and re-positioned to close a non-healing wound over a pressure point

Local flaps rely on…

local perfusion - no specific arterial supply.

Used for head neck and trunk

A caudal epigastric flap is an example of an _________.

axial parttern flap - used for head neck and trunk

What is a hernia?

A condition in which a part of an organ is displaced and protrudes through the wall of the cavity containing it

Contains a ring, sac, and contents.

What does a false hernia lack?

no epithelial lined sac.

Pathophysiology of a hernia

• Loss of domain

• Incarceration

  • Adhesions

  • Normal function may be impeded

• Strangulation

  • Blood supply compromised

  • Venous obstruction = congestion + transudate

  • Surgical emergency

Describe an umbilical hernia (SA)

• Common

• Congenital and heritable

• May have concurrent

  • Cardiac defects

  • Incomplete caudal sternal fusion

  • Cryptorchid

  • PPDH 

• Clinical signs rare

• May spontaneously resolve by 6 months of age

• Risk of bowel entrapment - see less often b/c small, but is a big problem.

Elective umbilical hernia repair (SA)

• Male - separate surgical incision

• Female - incorporate into spay incision

• Procedure

  • Careful skin incision over hernia

  • Dissect skin off of underlying tissue

  • Reduce or excise fat to expose ring

  • Close ring using PDS or similar.

When is an umbilical hernia an emergency in small animals?

• Intestinal adhesions

• Intestinal necrosis

• Septic abdomen

The inguinal canal contains

• Genital structures

  • Vaginal process

  • Spermatic cord (males), round ligament (females)

  • Genitofemoral artery, vein, nerve

• External pudendal vessels

Describe inguinal hernias in SA (signalment, risk factors). How to diagnose?

• 70-90% female - often see the uterus. Problematic (strangulation, pyometra)

• Estrus and pregnancy are risk factors

• L>R

Diagnose - palpation, rads/ultrasound

Surgical approach for inguinal hernia

• Multiple approaches

  • Over the hernia

  • Abdominal - easier to pull things back in through the abdomen. Helps if need to perform RNA

• Inguinal hernia surgery

  • Caudal midline laparotomy

  • Identify and reduce herniated structures to abdominal cavity

  • Increase hernial ring size if necessary

  • Check viability of all reduced tissue

  • Close inguinal ring

  • Important points

    • When closing the inguinal ring be careful of normal structures

      • Males: spermatic cord (with the genital branch of the genitofemoral nerve), ilioinguinal nerve, external pudendal  vessels (a and v)

      • Females: round ligament, genital branch of the genitofemoral nerve, and the ilioinguinal nerve, external pudendal vessels (a & v)

    • Always check the other side

    • If not reducible - dissect skin/mammary tissue laterally and caudally to expose hernia contents

What is a scrotal hernia?

• Variant of an inguinal hernia

• Viscera pass through internal inguinal ring. Inguinal canal, and external inguinal ring to end up in the scrotum

• Rare

• Often concurrent strangulation

• Chondrodystrophoid and brachycephalics

How does surgery differ for a reducible vs non reducible scrotal hernia?

• Reducible or non-reducible?

  • reducible 

    • Prescrotal incision running parallel to midline

    • Reduce and close external inguinal ring-partially if remaining intact, fully if neutering.

  • Non-reducible

    • Caudal midline laparotomy +/- = approach internal and external inguinal rings

    • Reduce hernial contents and evaluate viability

Abdominal wall ruptures are often caused by ________ therefore you must rule out concurrent ___________.

Polytrauma

• Rule out concurrent

  • Pneumothorax

  • Pulmonary contusions

  • V-tach

  • uroabdomen/hemoabdomen

  • Bile peritonitis

Describe the surgery for Abdominal wall ruptures, prepubic tendon avulsion/rupture and thoracic wall ruptures

• Abdomen

  • Approach via midline laparotomy

  • Care re aorta/ureters for repair of dorsolateral ruptures

  • In general

    • Fascia

    • Multiple layer

    • Pre-place sutures

    • 2/0 PDS

• Prepubic tendon avulsion/rupture

  • Pubis periosteum

  • Pre-drill holes in pubic brim

  • Non-absorbable suture

• Thoracic wall ruptures

  • May be no external punctures, but total loss/ separation of underlying thoracic wall musculature with rib separation/fracture and lung herniation

  • When exploring be prepared

    • Chest tube

    • PPV

    • Lung lobectomy.

Pathophysiology of diaphragm hernias

• Pathophysiology Polytrauma

  • Thoracic and abdominal pressures equalise

  • Loss of domain

    • Reduced tidal volume

    • Atelectasis

    • VQ mismatch

    • Impaired venous return

  • During induction - place them head up! Uses gravity to make sure things go into the abdomen, or if they are there we want them to stay there

  • incarceration/strangulation

  • Stomach

  • Liver lobe

  • Intestine

true/false: a gastric hernia is a true surgical emergency

true - stomach fills with gas. 

• Intubation, positive pressure ventilation, orogastric decompression, surgery

Clinical signs of diaphragmatic hernias

• dyspnea

• Decreased lung sounds 

• Asynchronous respiratory pattern - on inspiration thoracic wall moves out and abdominal wall moves in

Surgery for diaphragmatic hernia

• Immediate PPV

• Head up position

• Midline laparotomy

• Gentle traction to reduce organs

• Enlarge defect if necessary

• Before closing defect place small bore chest tube under direct palpation

• Seldinger technique

Post-op considerations and complications of diaphragmatic hernias

• Post op

  • May remain O2 dependent for 24-48hrs

  • Aspirate chest tube Q4

  • IV fluid support

  • Opioid analgesia

  • Early feeding

• Complications

  • Chronic

  • Intra-thoracic adhesions

  • Re-expansion pulmonary edema

  • Abdominal compartment syndrome = chronic ruptures - rare - bogota bag.

Peritoneopericardial diaphragmatic hernia (PPDH)

• Congenital

• Pericardial sac connects with abdominal cavity

• Frequently asymptomatic until

  • GI obstruction

  • Cardiac tamponade.

• Often concurrent with

  • Umbilical hernia

  • Caudal sternal defect-xiphoid absent

  • Identified at spay

• Surgery

  • Evacuate pericardial sac

  • Liver lobe herniation and necrosis

  • Complex

Surgical asepsis

• Complete absence of contamination by pathogenic organisms

• Prevents wound contamination by pathogenic organisms

  • Patient

  • OR personnel

  • Environment

_% of small animal surgical patients develop post-op wound infection

5%

Progression of surgical wound to infection depends on:

Which is most important?

• Microbial pathogens - most important

• Local wound environment

• Host defense mechanisms

Infection will develop if >___bacteria/gram of tissue

Dependent on

10^6

• dependent on:

  • Duration

    • For every hour of surgical time, infection rate approximately doubles

  • Type of procedure (degree of operative contamination)

    • Clean: 2.5-6%

    • Clean-contaminated: 2.5-9%

    • Contaminated: 5.5-28%

    • Dirty: 18-25%

  • Clean orthopedic procedures have higher infection rates than clean soft tissue procedures

Sources of microbial pathogens

• Endogenous

  • Within patient

  • Site-specific

• Exogenous

  • Air, surgeons, instruments, etc

  • Generally implicated in surgical infections (along with transient patient flora)

• Direct transfer

  • Blood, lymphatics, IV drugs, distant infection.

What is generalized pyoderma?

Elective procedures should not be performed if multiple skin lesions present: lesions likely contain bacteria that could contaminate the surgery site and/or incision = generalized pyoderma

Presurgical skin prep

• Humans - presurgical bathing conflicting results

  • Highest reduction of microbial counts when performed several times prior to surgery and with 4% chlorhexidine gluconate instead of other medicated soaps

• Veterinary - data not available

  • Prewash surgical site with a neutral, non-medicated soap is advised to start surgical antisepsis of the area

  • Veterinary patients do not dry - so don’t wash unless farm animals etc.

• Purpose: remove transient microorganisms and reduce resident flora for duration of surgery

• Clipping: within 4 hours of surgery = associated with lower incidence of surgical site infection

  • Preservation of the integrity of the natural skin barrier is key to reducing surgical site infection

    • Use least traumatic method (no razors): rashes and skin abrasions induced by shaving and clipping can provide a portal or entry for microorganisms

  • It is better to leave some hair than to give an animal clipper burn

Antiseptic application

• Scrub, paint, or spray equally control bacterial growth

• Povidone Iodine

  • More skin reactions including acute contact dermatitis (eye, prepuce)

• 4% chlorhexidine rinsed with saline or 70% isopropyl alcohol

  • Combination with 70%  isopropyl alcohol may result in higher residual antimicrobial activity7

  • CHXD 1% and 4% are effective

• CONTACT TIME!!!

• Single step process - faster and has been found to be equally effective sa the use of multiple soaps

• Alcohol based iodophor and chlorhexidine products seem to exhibit greater efficacy compared to the aqueous solutions

Describe how to drape your surgical patient

• Blood and fluid resistant

• Lint free, antistatic, able to maintain isothermic environment relative to patient

• Single-use disposable drapes: low cost and benefit in preventing SSI outweigh the use of reusable drapes

• Steps

  • Quarter drapes

    • Ideally disposable

    • Penetrating towel clamps

  • Second drapes

    • Should extend onto instrument table (which is first covered with its own drape

    • Clamps should not penetrate to deeper layers

• Ioban 2 self adhesive drapes

  • Sterile, waterproof, transparent and available with infused antimicrobial agents, typically an iodophor

  • Use of these with abbreviated skin preparation techniques is not superior to use of nonadhesive drapes

• Nonmedicated adhesive incise drapes should not be used because of their association with increased risk for surgical site infection

What is the primary source of surgical contamination

• Shedding OR personnel is primary sources of contamination = perineal area

• Closely weaved fabric decreases degree of bacterial dissemination, but overall effect of scrub suits on the environment is questionable - scrub suit with elastic cuffs or other occlusive seals better

• Routine laundering does little to decrease pathogenic bacteria on scrub suits

• Just a barrier

• Tuck top into pants

• No undershirts showing

• Tuck pants into socks

Purpose of pre surgical hand prep

• Hand hygiene is major deterrent for hospital acquired infections

• Purpose - remove and/or kill transient skin organisms and reduce resident microbiota for duration of the surgical procedure

  • Transient microbiota: colonize the superficial layers of the skin, easier to remove with hand washing, most common cause of surgical site infection

  • Resident microbiota: reside in the deeper layers of the skin, are more difficult to remove, considered to be less pathogenic on intact skin

• Ultimate goal: risk reduction for surgical site infections

Methods of hand prep

• Waterless

  • Hand washing increases prep time, cost, carbon footprint, water usage

  • Faucets common sources of pseudomonas spp and other gram negative bacteria

• Alcohol based hand rub is superior

  • The initial reduction of the resident skin flora (microbiota) is rapid and effective with alcohol-based hand rubs (bacterial regrowth to baseline values on the gloved hand takes more than 6 hours)

• Sublingual area is reported to have highest bacterial load despite hand scrubbing

true/false: Gown contamination in both open and closed technique 100% of the time, particularly around the cuff site, whereas no contamination patches were found when the assisted gloving technique was used.

true

which side is easier to ligate the vascular pedicle?

left - more caudal

leaves of the suspensory ligament

• Medial leaf = ipsilateral kidney

• Lateral leaf = bodywall at last rib

Describe feline spay flank approach

• Occasionally performed in a flank approach

• Landmarks - position in lateral with hindlimbs pulled caudally. The point of incision is the third point of an equilateral triangle created by the femoral head and the iliac crest

• Flank approach vs midline - more painful at 1 hour post op and discharge and less painful at 3d and 10d post op

  • See notes in powerpoint

Presentation and pathophysiology of pyometra

• Presentation

  • 4-10weeks post estrus (8yrs, nulliparous, large breed)

  • Depression, anorexia, vomiting, PU/PD

  • Purulent vaginal discharge in 75% = “open pyo”

• Pathophysiology

  • Endometrial hyperplasia, secondary infection E. coli

  • “Stump” pyometra can occur in spayed females, but concurrent with an ovarian remnant/exogenous progestogens

  • Septicemia, ADH antagonism by endotoxin

  • Obligate polyuria, sepsis -> severe dehydration, pre-renal azotemia, shock

    • NOT kidney disease = kidney can’t concentrate due to endotoxin.

How does a spay differ if the animal has a pyometra?

• Long midline incision

• Fully exteriorise uterus

• Gentle handling - can rupture

• Three clamp ligation technique ovarian pedicles

• Uterine vessels very prominent

  • Ligate each individually

  • Encircling ligature (Millers) below

• Don't oversew uterine stump

• Lavage abdomen with saline prior to closure

• Same approach with spay during C section