Anatomy + Suturing

Basic mammalian body plan; suturing a day 1 year one skill

What is suturing used for?

-Close wounds and support them during healing
-Ligate blood vessels and stop the bleeding (hemostasis)
-Support weak tissue (ex: hernia repair)

Types of needle holders

Mayo, olsen haegar, ghillies

Types of forceps

Tissue/serrated forceps, rat tooth forceps

Type of scissors

Mayo

Eyelet needle

Threaded through eye of needle, can be reused but will become blunt, creates bigger hole but is cheaper

Swaged on needle

Suture is directly attached to needle, single use (sharper), causes less tissue trauma and creates smaller hole, more expensive, comes in sterile prepped packets

Needles are usually what shapes? What are they used for?

Curved or straight, curved are used with instruments and straight are used with hands (rarely used at all)

Types of needle points

Tapercut, reverse cutting, round bodied

Tapercut needle point

Sharp but creates small hole
-Used in gut and bladder

Reverse cutting needle

strong, used for skin and fascia

Round bodied needle

Quite blunt, used in fat

What properties does suture material need to have?

Strong, uniform in size and diameter, easy to handle, good knot holding, not reactive, sterile, cost effective

Memory of suture

The tendency of the suture to return to its original packaged form (higher the memory the harder it is to handle - wants to keep its shape)

Handling of suture

Ease of use and ease of knot placement

Tensile strength of suture

Strength of the material

Duration of suture

Duration of strength (may lose strength but may not be full absorbed)

Types of suture material

Monofilament/multifilament, absorbable/non absorbable, natural/synthetic

Monofilament suture

Made of a single strong, cause less resistance (tissue drag), less likely to harbor bacteria

Multifilament suture

Made of several filaments that are twisted (catgut) or braided (polyglactin)
-Easier to handle but higher friction (greater tissue drag)
-Capillary action and can wick bateria

Non absorbable suture

Doesn't dissolve; long lasting
-used when sutures will be removed or long standing support needed from them (ex: hernia repair)
Ex: nylon (ethilon), polypropylene (prolene)

Absorbable suture

Provides support while wound is healing and are absorbed once has sufficient strength
-Different material break down at different rates
-Short duration = appreciable strength persists for less than 21 days
-Long duration = appreciable strength persists greater than 21 days
ex; Polydioxone, polyglicaprone, polyglactin 910, catgut

Polygalctin 910

Vicryl; multifilament braided synthetic material
-Easy to handle
-Strength reduced to 50% at 21 days
-Very popular
-Used for oral wounds, subQ, intradermal

Poliglecaprone 25

Monocryl, monofilament synthetic
-Strength reduced to 50% at 7 days
-Easy to handle
-Used for subcutaneous tissues, intradermal sutures, bladder and intestine

Polydioxanone

PDS, monofilament synthetic
-Long duration, 50% strength loss at 5-6 weeks
-Has a lot of memory so more difficult to handle
-Knot security is poorer than other materials
-Needs for throws
-Useful when longer support is needed
ex: linea alba, muscle intestine

Catgut

Multifilament natural material derived from sheep or cattle intestine
-Sometimes treated with chromium salts (chromic catgut)
-Causes intestine tissue reaction
-Unpredictable absorption
-Cheap
-Used for LIGATURES ONLY
-There are way better options than this one

Natural suture

Broken down by phagocytosis and proteolysis; varies between patients and wounds
-Associated with inflammatory reactions

Synthetic material suture

Made of chemical polymers which are broken down by hydrolysis ; very predictable

Ideal suture is...

synthetic (predictable absorption and loss of strength with less inflammation), monofilament (less drag and doesn't wick), low memory with good knot security, as strong as the tissues at placement

Two types of suture classifications

USP - United States Pharmacopoeia (6-0 small to 2 large)
PhEur - European Pharmacopoeia - metric (1.5 metric small to 5 metric large)

** see chart on common small animal materials and suture sizes**

***see front***

Suture knot is what part of the suture?

The weakest part, failure can have disastrous consequence
-Care must be taken to place throws properly so granny knots aren't tied
-Small diameter suture has greater knot security
-Monofilament has poor knot security because it has more memory and less friction

Throw

Basic unit of knot

Turn

Number of twists per throw (single turn, double turn, surgeons turn- starts most knots)
-Less slippage than single turn throw due to increased contact

Surgeons knot

Double throw followed by a single throw, used commonly and is secure

Square knot

Single throw followed by a single throw, commonly used knot to secure - reef knot

Granny knots

Weak knots, will unravel , asymmetric, caused but not altering direction of throws

How to try a basic knot

Place needle holders in the center of the knot, swap sides with your hands as each throw is tightened

How do you grip a needle holder?

Holding the needle mid shaft or 2/3rds from the point

For which tissue is simple continous not commonly used

Skin

What is the throw pattern for a surgeon's knot?

2-1-1

When starting a simple continous suture, how far from the incision should you begin?

.5cm

After placing a simple interrupted suture in the skin, what length should the ends be cut when using a surgeon's knot?

1-2cm

When holding your needle holders, which digits should be in the handle rings?

Thumb and ring finger

When performing a simple continous suture pattern how far apart should each insertion along the wound edge be?

5mm

What is the correct way to hold rat-toothed forceps

Pen grip non-dominant hand

Muscle fiber type 1

slow twitch, oxidative, white

Type 2a muscle

fast twitch oxidative glycolytic

Type 2b muscle

fast twitch glycolytic anaerobic

Selection for muscle mass has lead to what type of muscle fiber

Type 2

Anatomy

The scientific study of the body and how its parts are arranged

Gross anatomy

Study of structures that can be seen with the naked eye

Microscopic anatomy

deals with structures too small to be seen with the naked eye

Systematic anatomy

body structure is studied system by system

Why do we learn anatomy?

Have to understand normal tissue to understand its pathology
-Also direct application (surgery, imaging, exam)

Etymology

the study of word origins - intended to be descriptive or informative

Nomina atomica (NAV)

Internationally agree on terminology that is used - many words are anglicized

Medial plane

imaginary line that divides the body into equal left and right halves

Transverse plane

horizontal division of the body into upper and lower portions

Is directional terminology affected by posture or changes in position of the animal?

No! Seen from the animals point of view

Dorsal

toward the back

Caudal

Towards the tail

Ventral

Toward the belly

Cranial

Toward the head

Rostral

toward the nose

Proximal

Nearer to the trunk of the body (closer to the point of attachment)

Distal

away from the trunk or point of attachment

Medial

Towards the median plane

Lateral

Away from the median plane

Axial Directional Term

Close to the axis (between the digits)

Abaxial Directional Term

Away from the axis

Above the carpus (wrist)

cranial and caudal

Below the carpus

Dorsal and palmar

Hindlimb above the tarsus (ankle)

Cranial and caudal

Below the tarsus

Dorsal and plantar

Axial skeleton

skull, vertebral column, rib cage

appendicular skeleton

Bones of the limbs and limb girdles that are attached to the axial skeleton

Regions of the vertebral column

Cervical, thoracic, lumbar, sacral, caudal/coccygeal

Vertebral formula of a dog

C7, T13, L7, S3, Cy20-23

Limbs of the forelimb

Scapula, humerus, radius/ulna, carpal bones, metacarpal bones, phalanges (proximal, middle and distal phalanx)

Forelimb joints

Shoulder
Elbow
Carpus
Metacarpo-phalangeal / fetlock
Proximal interphalangeal
Distal interphalangeal

Hindlimb bones

Pelvis
Femur
Tibia & fibula
Tarsal bones
Metatarsal bones
Phalanges:
Proximal phalanx
Middle phalanx
Distal phalanx

Hind limb joints

Sacroiliac, hip, stifle, tarsus, metatarso-phalangeal/fetlock, proximal interphalangeal, distal interphalangeal

Trunk contains which 3 body cavities

Thoracic cavity, abdominal cavity, pelvic cavity

Dorsal limits

thoracic region of the vertebral column

Lateral limits

Ribcage (ribs and associated structures)

Ventral limits

sternum

Cranial limits

thoracic inlet

Caudal limits

diaphragm

cardiovascular system

heart and blood vessels

Respiratory system

Brings oxygen into the body. Gets rid of carbon dioxide.

Digestive system

Breaks down food into absorbable units that enter the blood for distribution to body cells.

Specific function of the thoracic wall

Aid in respiration (breathing) - expands and contracts along with breathing

Abdominal cavity dorsal limits

lumbar region of the vertebral column

Abdominal cavity lateral and ventral limits

muscular abdominal wall

Cranial limits of abdominal cavity

diaphragm

Caudal limits of abdominal cavity

Pelvic inlet

Is there a physical barrier between the abdominal and pelvic cavities?

No - because needs to be able to expand with digestion and pregnancy

What does the abdominal cavity contain

digestive system, urinary system, female reproductive system

Specific function of muscular abdominal wall

allows for expansion, aids in abdominal press

Pelvic cavity dorsal limit

Sacral region of vertebral column