Surgical Diseases 1 Flashcards
What are the 4 NRC Sx Classifications
- Clean (Non-traumatic, uninfected, no break in aseptic technique, non-inflamed; elective with 1º closure & no drain)
- Clean-Contaminated (Controlled entering into luminal organ, minor break in aseptic technique)
- Contaminated (Open, fresh traumatic wound; acute, non-purulent inflammation present; major break in aseptic technique e.g. spillage of abdominal contents)
- Dirty (Purulent inflammation; perforated organs; traumatic wound w/ devitalized tissue; foreign material or fecal contamination; procedure > 4 hours long)
NRC Surgical Classification
Routine spay or castration
Clean
NRC Surgical Classification
Exploratory laparotomy, no entering of luminal organs
Clean
NRC Surgical Classification
Exploratory laparotomy for FB removal
Clean-contaminated
NRC Surgical Classification
Cystotomy
Clean-contaminated
NRC Surgical Classification
Cystotomy/laparotomy with significant abdominal contamination
Contaminated
NRC Surgical Classification
Pyometra
Contaminated
NRC Surgical Classification
Peritonitis
Dirty
NRC Surgical Classification
Necrotic traumatic tissue > 4-hour duration with 1º closure
Dirty
Contamination vs Infection
Contamination: presence of any abnormal bacterial organisms in any field, WITHOUT inflamamtion
Infection: presence of inflammation AND 10^5 abnormal bacterial per gram
difference = presence of bacterial invasion/colonization
The 5 cardinal signs of inflammation:
- Redness
- Heat
- Swelling
- Pain
- Loss of function
The 6 Halsted’s Principles:
- Aseptic technique
- Gentle tissue handling
- Control hemorrhage
- Eliminate dead space
- Accurate apposition of tissue w/ minimal dead space
- Preservation of blood supply
How often should prophylactic ABX be administered and when should they be d/c
Start 30-60 mins prior to sx (ensures peak tissue concentration @ time of incision + throughout period of contamination) + re-dose every 2 half lives while incision is still actively open. D/c within 24h of closure.
E.g., cefazolin 1/2 life = 45mins -> re-dose q90mins
When are post-op ABX indicated?
- All Dirty procedures
- Pt is exhibiting clinical signs of illness (sepsis)
- When consequences of infection are catastrophic (permanent implants)
Absorbable suture definition
- Name the multifilaments (4)
- Name the monofilaments (2)
Loses tensile strength @ 60-90 days in living mammalian tissue
- Multi: Catgut, Chromic gut, Vicryl, Vicryl Rapide
- Mono: Monocryl, PDS II
Non-absorbable suture definition
- Name the multifilament
- Name the monofilaments (2)
Retains almost all tensile strength for > 60 days
- Multi: Silk
- Mono: Nylon, Prolene
Polyglactin 910
Vicryl
Poliglecaprone 25
Monocryl
Polydioxanone
PDS II
Polypropylene
Prolene
Which suture types can be used in contaminated wounds? (3)
Monocryl, PDS II, Prolene
How long does it take for monocryl to lose 50% of tensile strength? 100%?
50% lost @ 7 days
100% lost in 4 months
How long does it take Vicryl to lose 50% of tensile strength? 100%?
50% = 2-3 weeks
100% = 56-70 days
How long does it take PDS II to lose 50% of tensile strength? 100%?
50% = 4-6 weeks
100% = 6 months (have seen longer)
Which suture is good to use in tendons, ligaments, joint capsule, and fasica? Why?
Prolene (non-absorbable monofilament) b/c min. tissue reactivity + LEAST thrombogenic
Mono vs Multifilament
Mono:
- Pros: lower tissue drag, decreased capillarity
- Cons: decreased knot security, increased memory
Multi: opposite of mono
When to use taper point vs reverse-cutting suture needle
Taper Point: soft tissue, luminal organs
Reverse-Cutting: tough, thick, fibrous tissue or long/large incision
Suture choice for tie-over bandage for a necrotic wound
Prolene or Nylon (non-absorbable monofilaments) b/c tie-over bandages require stay sutures that need to maintain tensile strength for 5 weeks
Suture choice for entropion sx
Vicryl w/ long tags, 3-0 to 5-0
- absorbable multi; soft, min. tissue reactivity
Suture choice for PU surgery (urethra gets sutured!)
Taper point w/ absorbable monofilament (monocryl is softer than PDS II)
Suture choice for SCC removal on the pinna of an outdoor cat
Absorbable suture that does NOT stick around for long (vicryl; monocryl)
Suture choice in fast-healing tissue like oral mucosa
Monocryl, Vicryl
Suture choices for toe amputation (internal tissue + dermis)
- PDS II (tissue)
- Prolene or Nylon (dermis)
Long healing time b/c on extremtiy
What are the phases of wound healing
- Inflammatory/debridement
- Proliferative
- Maturation
What cells are key in inflammatory phase
Clotting factors (send 1st molecular signals), neutrophils (early- kill bacteria +debride necrotic tissue), and macrophages (days 3-5; phagocytosis)
Key characteristics of Proliferative Phase
- Granulation tissue (collagen, fibroblasts)
- Epithelialization (epithelial migration)
- Contraction (myofibroblasts)
Contraction v Contracture
Contraction: healthy migration of epithelial cells during proliferative phase (normal muscle shortening)
Contracture: abnormal shortening of muscles that leads to stiffness/shortening of joints or natural orifices, preventing normal movement/function
Purpose of Maturation phase
Remodeling//Strengthening
- skin will only regain ~80% of original strength
Why is proper oxygenation of healing tissue important?
- neutrophils need O2 to kill bacteria (free- oxygen radicals)
- needed for collagen production
What phase is inherently resistant to infection?
Granualtion tissue (proliferative phase)
What can delay and/or reverse the proliferative phase?
Presence of inflammation – infection or necrotic tissue
What is the goal of tissue debridement
To remove necrotic/devitalized/severely contaminated tissue, any foreign material in order to decrease risk of infection (which delays/prevents proliferative phase)
Surigcal debridement: layered vs. En Bloc
Surgical debridement = selective removal
Layered: begin at wound surface, then progress to depths
En bloc: excise entire wound + margin of normal tissue
“when in doubt, cut it out”
What is the most effective way to reduce bacterial numbers on wound surface?
LAVAGE!!
- large syringe + 18g needle
- fluids (tap water, 0.9% saline, LRS, NormR)
- saline bottle w/ puncture holes
When are topical ABX indicated?
Inflammatory/debridement phase
contraindicated during prolif phase
When are systemic ABX indicated and contraindicated?
Presence of infected tissue OR NRC Dirty classification
- NOT indicated for contaminated wound during inflammatory phase OR healthy wound during proliferative phase
- Primary closure (1st intension)
- Delayed primary closure
- Second intention
- Third intention
1. Primary closure (1st intension)
- surgical incision, clean/fresh wounds (< 6 hours old)
2. Delayed primary closure
- 3-5 days after injury, BEFORE granulation tissue appears
- used for heavilty contaminated/infected wounds, wounds > 6 hours old, mass removal
3. Second intention
- allow for contraction & epithelialization to occur
- small or large wounds; failure of 1ºclosure
4. Secondary Closure (3rd intention)
- wound closed > 5 days post injury
- granulation tissue present
- seeverly infected wounds/massive tissue destruction
Layers of a bandage
- Primary layer: dressing/contact layer
- Secondary layer: absorption, stabilization, and pressure (+/- splint)
- Tertiary layer: additional protection, pressure
Inflammatory vs proliferative phase Dressing goals
Inflammatory: debridgement + decontamination (ABX)
Proliferative: hold cytokines/cells in w/out disrupting fragile tissue
Dressings for inflammatory phase
- Wet-to-dry bandage
- Honey/sugar (hyperosmotic properties. non-selectively draws out fluid//bacteria)
Dressings for proliferatie phase
- tefla pad + triple ABX ointment
- petroelum-infused gauze
- hydrogel/hydrocolloids
- calcium alginate
- polyurathane foam
Does epithelial migration occur quicker in dry or moist wound environments? Why?
Moist
- physiologically favors cell migration/ECM formation
- promotes autolytic debridement
Do bandage changes occur more frequently in inflammatory or proliferative phase?
Inflammatory (q1-2 days)
proliferative = q3-7 days
3 most important considerations in fracture repair
Stress, strain, bending moment
How can the stress on a fracture be reduced?
Stress = force/unit area
- area is indirectly proportional to stress -> increase plate area (plate thickness) on fracture
- e.g., addition of plate rod increases unit area
Severity of bone fracture is directly correlated to what?
1. Rate of loading (viscoelastic property)
- Bone is stronger when loaded rapidly
2. Loading direction (anisotrophic nature)
- Bone is stronger/most resistant to axial/compressive loads
- bone is much less resistant to loads along its sides (radial), surface (tangential), and especially 90º to its long axis (transverse)
- Rapidly loaded bones release more energy when they reach failure point -> more complex fractures + greater soft tissue damage
- However, these bones are stronger and experience fewer fractures when impacted with rapidly loaded forces. will eventually fracture when failure point is reached.
What are the 4 principle forces causing fractures?
- Bending
- Torsional
- Compressional (axial load)
- Distraction
Biomechanics of Fractures
Stress and strain are scalar quantities. What does this mean (what do they measure)?
They measure the quantity and/or magnitude of something
other examples: temp, energy, speed, distance
Tensors are Scalars and Vectors. Vectors measure magnitude AND direction (force, acceleration velocity).
Blood supply to bone is sourced how?
Extraosseously -> important consideration for internal/external fixation!!
Main difference b/w non-locking and locking plates
Locking plates’ screws are locked into the plate itself, creating a fixed angle construct and b/w plate and bone and eliminating the need to rely on bone-plate friction for stability.
What are the only bones interlocking nails can be used on?
Femurl, tibia, humerus
Interlocking nails
Metallic implants used for the repair of traumatic long bone fractures
- large diameter rod inserted into medullary cavity -> secured w/ locking bolts going from one cortex to another, capturing the nail inside the medullary cavity
