All Sections Flashcards
(102 cards)
1
Q
What are the layers of the skin?
A
Epidermis
- “Come Let’s Get Some Beer”
- Stratum corneum
- Stratum lucidum
- Stratum Granulosum
- Stratum Spinosum
- Stratum Basale
Dermis
- Upper (papillary)
- Lower (reticular)
Subcutaneous tissue
2
Q
Compare full-thickness vs split-thickness skin grafts.
A
Full-thickness includes all of the dermis down to subcutaneous tissue.
Split-thickness can be thin (epidermis), medium (papillary dermis), thick (reticular dermis).
3
Q
How thick are different types of STSG?
A
Thin: 0.005 - 0.012 in (0.2 - 0.3 mm)
Medium: 0.012 - 0.018 in (0.3 - 0.45 mm)
Thick: 0.018 - 0.030 in (0.45 - 0.75 mm)
4
Q
Describe the blood supply to the hand.
A
Source arteries
- Radial artery (b/w FCR/brachioradialis)
- Ulnar artery (lateral to ulnar nerve)
- Supplemental arteries
- anterior interosseus artery
- posterior interosseus artery
- median artery (occassionally)
(A) Superficial arch
- predominant supply is ulnar artery
- main supplier to the digits (except thumb and radial D2)
- digital arteries run volar to nerves in palm, dorsal in digits
(B) Deep arch
- predominant supply is radial artery
- supplies thumb and radial D2
(C) Dorsal arteries
- PI artery and dorsal perforating branch of AI artery form dorsal carpal arch –> dorsal MC arteries
(D) Veins
- Deep veins follow deep arterial system as venae comintantes
- Superficial veins on dorsal surface contribute to basilic (ulnar) and cephalic (radial) vein system
5
Q
Name the carpal bones.
A
“She Looks Too Pretty, Try To Call Her”
Scaphoid
Lunate
Triquetrum
Pisiform
Trapezium
Trapezoid
Capitate
Hamate
6
Q
Describe sensory distribution in the hand.
A
Median
- volar D1, D2, D3, radial side of D4
- dorsal D1, D2, D3, radial D4 (distal to PIPJ)
Ulnar
- volar and dorsal D5, ulnar side of D4
Radial
- dorsal hand excluding areas described above
7
Q
Describe the flexor mechanism.
A
- FDS inserts at proximal middle phalanx
- splits midway along proximal phalanx at Camper’s chiasm
- FDP inserts at proximal distal phalanx
8
Q
Describe the extensor mechanism.
A
- Extensor tendon runs midline, inserting as the central slip at the proximal middle phalanx
- Lateral bands branch off of central slip, just proximal to PIPJ, inserting into proximal distal phalanx at terminal insertion
- Triangular ligament runs within lateral bands near the terminal insertion
- Lumbricals and interossei insert into the extensor hood
- Extensor hood is made up of proximal sagittal fibres and distal oblique fibres, covering the proximal phalanx
9
Q
Label the following nail anatomy:
A
- Hyponychium
- Sterile matrix
- Germinal matrix
- Ventral floor
- Lunula
- Eponychium
- Dorsal root
- Distal phalanx
- Extensor tendon
- Flexor tendon
10
Q
Which type of tendons require operative repair?
A
Flexor tendons - all require OR repair.
Extensor = ER repair (unless proximal/multiple tendons).
11
Q
Label the following cross-section of the carpal tunnel:
A
- FCU tendon, ulnar nerve, ulnar artery
- Palmaris longus tendon, median nerve
- FPL, FCR, Radial artery
- Carpal bones: hamate, capitate, trapezoid, trapezium
- Carpal tunnel: transverse carpal ligament (flexor retinaculum), FDS x 4, FDP x 4, median nerve, FPL
- Note:
- FDS to long and ring are superficial, index and small are deep (think “34 is higher than 25”)
- FDP has one muscle belly (think one “profound” belly), whereas FDS divides into four bundles
12
Q
Name the six extensor compartments of the wrist.
A
Compartments lie under the extensor retinaculum.
Radial to medial:
- APL; EPB
- ECRL; ECRB
- EPL (passes around Lister’s tubercle)
- EDC (superficial); EIP (deep)
- EDM
- ECU
Note:
- EIP & EDC both supply the index finger, EDM & EDC both supply the small finger
- In both cases, EDC is radial and other extensor is ulnar
13
Q
Name the components of the brachial plexus (think of the acronym).
A
“Real Teens Drink Cold Beer”
- Roots (C5, C6, C7, C8, T1)
- Trunks (Superior, Middle, Inferior)
- Divisions (Anterior, Posterior)
- Cords (Lateral, Posterior, Medial)
- Branches (“MARMU” - musculocutaneous, axillary, radial, median, ulnar)
14
Q
What are causes of saddlenose deformity?
A
-
Granulomatous disorders
- Granulomatosis with polyangiitis
- Infection (mycobacterial - leprosy [Hansen’s])
- Sarcoidosis
-
Neoplastic conditions
- EBV-associated nasal lymphomas
- Relapsing polychondritis
- Primary atrophic rhinosinusitis
- Congenital syphilis
-
Iatrogenic
- Trauma (most common cause)
- Cocaine
- Surgery
- Radiations
15
Q
Draw/label the brachial plexus.
A
16
Q
Label the bones/landmarks of the face and skull.
A
- temporal
- ethmoid
- lacrimal
- maxilla
- nasal
- zygoma
- zygomatic process of temporal bone (zygomatic arch)
- alveolar process of maxilla
- mental foramen
- mandibular symphisis
- mastoid process
- sphenoid bone
- body of the mandible
17
Q
Name the craniofacial buttresses.
A
Horizontal buttresses
- Frontal bar
- Upper transverse maxillary (inferior orbital rim)
- Lower transverse maxillary (hard palate)
- Upper transverse mandibular
- Lower transverse mandibular
Vertical buttresses
- Medial maxillary (nasomaxillary)
- Lateral maxillary (zygomaticomaxillary)
- Posterior maxillary (pterygomaxillary)
- Posterior vertical (vertical mandible)
18
Q
What are the factors that determine lesion excision margins?
A
- Type of lesion
- Lesion diameter
- Lesion depth (for melanoma)
19
Q
List the precursors of BCC, SCC, and malignant melanoma.
A
BCC
- Nevus sebaceous of Jadassohn
SCC
- Actinic keratosis
- Bowen’s disease (SCC in situ)
- Bowenoid papulosis (genitals)
- Paget’s disease
- Leukoplakia (mouth)
- Erythroplasia (Bowen’s of the penis)
Malignant melanoma
- Lentigo maligna (in situ)
- Giant congenital nevus
- Dysplastic nevus
20
Q
Label the ear.
A
A. Crura of antihelix
B. Crus of helix
C. Anterior notch
D. Supratragal tubercle
E. Tragus
F. Intertragal notch
G. Lobule
H. External auditory meatus
I. Antitragus
J. Posterior auricular sulcus
K. Antihelix
L. Cavum conchae
M. Cymba conchae
N. Concha
O. Scaphoid fossa
P1. Helix
P2. Darwinian tubercle
Q. Triangular fossa
21
Q
What are the surgical margins for BCC, SCC, and melanoma?
A
BCC
- 3 mm for nonaggressive BCC subtypes (i.e., nodular and superficial) < 2 cm
- 5-mm margin for larger BCCs or BCCs with an aggressive histological subtype (i.e., infiltrative or micronodular)
SCC
- 4 mm margin for lower-risk lesions (well-differentiated, <2 cm, not on the scalp, ears, eyelids, lips, or nose, and do not involve subcutaneous fat)
- 6 mm margin for lesions that are larger than 2 cm, invasive to fat, or in high-risk locations (ie, central face, ears, scalp, genitalia, hands, feet)
Melanoma
- pTis melanoma (in situ): 5 mm margin
- pT1 melanoma (<1.0 mm): 1 cm margin
- pT2 melanoma (1.0–2.0 mm): 1–2 cm margin
- pT3 melanoma (2.0–4.0 mm): 1–2 cm margin
- A wider margin (2 cm) is optimal, where possible, depending on tumour site and surgeon/patient preference.
- pT4 melanoma (>4.0 mm): 2 cm margin
22
Q
What are the different subtypes of BCC?
A
- Noduloulcerative (typical)
- Pigmented variant
- Superifical variant
- Sclerosing (morpheaform) variant
23
Q
What are the subtypes of malignant melanoma?
A
- Lentigo maligna (in situ)
- Lentigo meligna melanoma (invading into dermis)
- Superficial spreading (most common)
- Nodular
- Acrolentiginous (palmar, plantar, subungual, mucous membranes)
24
Q
What are the 5-year survival rates for different Breslow depths/cancer stages of melanoma?
A
<1.0 mm (Stage I): 90%
- 0-2.0 mm (Stage II): 70%
- 0-4.0 mm (Stage III): 45%
>4.0 mm (Stage IV): 10%
25
What is a traumatic tattoo?
Traumatic tattos are permanent discolourations resulting from new skin growth over foreign material or dirt left in the dermis.
26
What is the toxic limit for lidocaine (Xylocaine)?
**5 mg/kg without** epinephrine (45-60 min)
**7 mg/kg** **with** epinephrine (2-6 h)
27
What is the toxic limit for bupivicaine (Marcaine)?
**2 mg/kg without** epinephrine (2-4 h)
**3 mg/kg with** epinephrine (3-7 h)
28
What are symptoms of lidocaine toxicity (local anaesthetic toxicity)?
**Initial signs:**
* circumoral numbness
* light-headedness
* drowsiness
**Later signs:**
* tremors
* seizures
**Late signs:**
* cardiac
* respiratory
29
Calculate the toxic limit and max bolus injection for a 70 kg patient, using 1% lidocaine without epinephrine.
Lidocaine w/o epi = 5 mg/kg
5 mg/kg X 70 kg = 350 mg
1% lidocaine = 10 mg/1000 mg = 10 mg/g = 10 mg/cc
350 mg / (10 mg/cc) = 35 cc
**Therefore, toxic limit is 350 mg and max bolus is 35 cc.**
More lidocaine can be added after 30 mins.
30
What can you do to ensure good suturing cosmesis?
* Make incisions along relaxed skin tension lines (Langer's lines)
* Attain close apposition of wound edges
* Minimise tension on skin by closing in layers
* Every wound edges
* Use appropriately size sutures
* 5-0, 6-0 on face
* 3-0, 4-0 elsewhere
* Ensure equal width and depth of tissue on both sides
* Remove sutures in a timely manner
* 5-7 d from face
* 10-14 d from scalp/extremities
31
What are the two important first steps to perform with a wound (besides asking about tetanus status)?
Irrigation & debridement
32
What does irrigating do?
Removes bacteria; removes nidi of infection from foreign material, surface clots, devitalised tissue.
33
What needle gauge and syringe size should be used for irrigation? What pound-force per square inch (psi) does this generate?
19-gauge needle
35 cc syringe
~ 18 psi
34
What must be done to ragged wound edges?
Irregular or ragged wound edges must be excised to produce sharp wound edges that will assist with healing when approximated.
Wounds left unapproximated \>8h should be debrided to ensure wound edges are optimised for healing.
35
List the following:
* absorbable monofilament sutures
* non-absorbable monofilament sutures
* absorbable multifilament sutures
* non-absorbable multifilament sutures
* absorbable monofilament sutures
* Monocryl
* PDS II (polydioxanone)
* Plain gut / fast absorbing gut
* non-absorbable monofilament sutures
* Prolene (polypropylene)
* Nylon (Ethilon)
* absorbable multifilament sutures
* Vicryl
* non-absorbable multifilament sutures
* Ethibond
36
List the uses of absorbable vs non-absorbable sutures, and monofilament vs multifilament sutures.
**Absorbable**
* Deep sutures under short-term tension
* Skin closure in children
* At least 50% of strength lost in 4 weeks
**Non-absorbable**
* Skin closure
* Sites of long-term tension
* Lower likelihood of wound dehiscence
* More difficult to tie
* Makes track marks
**Monofilament**
* Optimal for contaminated and infected wounds (lower likelihood of bacterial trapping)
* Slides through tissue w/ less friction
* More memory/stiffness
**Multifilament**
* AVOID in contaminated wounds
* Less memory/stiffness therefore easier to work with
37
List the different types of suturing methods and their benefits.
* **simple interrupted:** can almost always be used
* **subcuticular:** good cosmetic result but weak; used w/ deep sutures; not used in trauma
* **vertical mattress:** for areas difficult to evert (e.g. volar palm of hand)
* **horizontal mattress:** everting; time saving
* **running "baseball stitch":** time saving; good for haemostasis
38
List three other types of skin closure methods (not sutures).
1. **Tapes**
* ****may work for superficial wounds with opposable edges
* cannot be applied to actively bleeding wound
* will prevent surface marks
* can be applied primarily or after suture sutures have been removed
2. **Skin adhesives**
* ****e.g. Dermabond (2-octylcyanoacrylate)
* works well on small areas w/o much tension or shearing
* may cause irreversible tattooing
3. **Staples**
* ****steel-titanium alloys that incite minimal tissue reaction
* healing comparable to wounds closed by sutures
39
What are some tips for proper lesion excision?
* run incision along relaxed skin tension lines (minimises scar)
* use elliptical incision (prevents dog ears)
* length of ellipse will be approx. 3x width
* undermine wound edges to release tension (if needed)
* use layered closure, including dermal sutures, when wound is deeper than superficial (decreases tension)
40
Do relaxed skin tension lines (Langer's lines) run parallel or perpendicular to muscle fibres?
* Perpendicular to muscle fibres
* Parallel to existing wrinkle lines
41
Name the four types of skin biopsy.
1. **Shave biopsy**
* superficial lesions (non-pigmented)
2. **Needle biopsy**
* ****breast masses / LNs
3. **Incisional biopsy**
* ****punch or ellipse within lesion
* take biopsy along border with normal skin
* punch knives range from 2-10 mm diameter
* punches \>3mm best to be closed w/ sutures to prevent scarring
4. **Excisional biopsy**
* ****complete removal for diagnostic and/or therapeutic purposes
* best for small lesions that are easily removed and closed
* always requires suture closure
42
What are the risks and benefits of adding epinephrine to local anaesthetic?
**Risks**
* avoid in patients with vascular compromise
* can be used anywhere except significantly injured digits (e.g. saw injury)
* mantra of "fingers nose penis toes" no longer followed
**Benefits**
* constrict blood vessels which:
* decreases bleeding
* prolongs anaesthesia
* limits lidocaine toxicity
43
Which antiseptics can be used on the face?
**Chlorhexidine**
* comes in [c] 0.5-4% -- only use lower [c] on the face otherwise risk of burning mucous membranes
* flammable -- dry completely before cautery
**Betadine**
* 7.5% povidone-iodine safer around eyes/ears/mucous membranes
Both solutions are bacteriostatis and bactericidal.
44
Distinguish between laceration, abrasion, contusion, avulsion, puncture wound, and crush injury.
**Laceration**
* cut or torn tissue
**Abrasion**
* superficial skin layer removed; variable depth
**Contusion**
* injury caused by forceful blow; entire outer layer of skin is intact but injured
**Avulsion**
* tissue/limb forcefully separated from surrounding tissue, either partially or fully; "de-gloving"
**Puncture wound**
* cutaneous opening relatively small as compared with depth (e.g. needle)
* includes _bite wounds_
**Crush injury**
* caused by compression
Also: **Thermal and chemical wounds**
45
Define "wound".
Disruption of the normal anatomical relationships of tissue as a result of injury.
46
List local and general factors influencing wound healing.
**Local (reversible/controllable)**
* mechanical (local trauma, significant crush, avulsion, tension)
* blood supply (ischaemia/circulation)
* temperature
* technique and suture materials
* retained foreign body
* infection
* venous hypertension
* peripheral vascular disease
* haematoma/seroma (also increases infection rate)
**General (often irreversible)**
* age
* nutrition (protein, vitamin C, O2)
* smoking
* chronic illness (e.g. DM, cancer, CVD)
* immunosuppression (steroids, chemo)
* collagen vascular disease
* tissue irradiation
47
Name the layers of the upper eyelid (remember the 4-5-7 rule).
**Lower 5 mm: 4 layers**
1. skin (anterior lamella)
2. orbicularis oculi (anterior lamella)
3. tarsus (posterior lamella)
4. conjunctiva (posterior lamella)
**Middle 5 mm: 5 layers**
1. skin
2. orbicularis oculi
3. levator aponeurosis
4. tarsus
5. conjunctiva
**Upper 10 mm: 7 layers**
1. skin
2. orbicularis oculi
3. septum
4. preaponeurotic fat
5. levator aponeurosis
6. Müller's muscle (inserts into tarsus)
7. conjunctiva
48
Name the layers of the lower eyelid (4-7).
**Upper 5mm: 4 layers**
1. skin
2. orbicularis oculi
3. tarsus
4. conjunctiva
**Lower 5mm: 7 layers**
1. skin
2. orbicularis oculi
3. septum
4. pre-capsulopalpebral fascia fat
5. inferior sympathetic muscle (equivalent to Müller's in upper lid)
6. CPF (equivalent to levator aponeurosis)
7. conjunctiva
49
What is the distinction between canthopexy and canthoplasty?
**Canthopexy**: lateral canthal tendon of the eye is _not cut_, but is fixated to the orbital rim.
**Canthoplasty**: lateral canthal tendon is _cut_ and then secured to lateral orbital rim (at Whitnall's tubercle).
50
Define ectropion and entropion.
**Entropion**: eyelid inverted.
**Ectropion**: eyelid everted.
51
How long does it take a scar to fully mature?
1 to 2 years
52
What are the three phases of wound healing?
1. **Inflammatory (Days 1-6)**
* ****limits damage, prevents further injury
1. _Haemostasis_
* vasoconstriction + platelet plug
2. _Chemotaxis_
* __migration of macrophages and PMN
* neutrophils (24-48 h); macrophages (48-96 h); lymphocytes (5-7 d)
2. **Proliferative (Day 4 - Week 3)**
* ****fibroblasts attracted and activated by macrophage growth factors
1. _Collagen synthesis (mainly type III)_
* tensile strength begins to increase at 4-5 days__
2. _Angiogenesis_
* relieves ischaemia
3. _Epithelialization_
3. **Remodelling (Week 3 - 1 year)**
* ****increasing collagen organisation and stronger crosslinks
1. _Contraction_
2. _Scarring_
3. _Remodelling of scar_
* __type I replaces type III collagen until normal 4:1 ratio achieved
* peak tensile strength at 60 d -- 80% of pre-injury strength
53
Contrast hypertrophic and keloid scars.
**Type**
Hypertrophic
Keloid
**Definition**
Scar within original boundaries
Scar outside original boundaries
**Location**
Any location; often on extensor surfaces of joints
Commonly on sternal skin, shoulders, upper arms, earlobes, cheeks
**Change in size**
Regress with time
Grow for years
**Collagen**
Fewer thick collagen fibres
Thick collagen
**Mucoid matrix**
Scanty matrix
Mucoid matrix
**Elevation**
Flatten over time
Remain elevated \>4mm
**Initiation**
Appear within one month
Appear at 3 months or later
**Skin type**
Less association with pigmentation
More common in darker skin types (genetic component)
**Appearance**
Red, raised, widened, pruritic
Red, raised, widened beyond scar borders, pruritic (constant collagen deposition and growth)
**Treatment**
Massage, pressure garment, silicone sheeting, corticosteroid injection (Kenalog – triamcinolone), surgical excision (may recur)
Multimodal: pressure garments, silicone sheeting, steroid injection, fractional carbon dioxide ablative laser, radiation (sometimes with excision – high risk of recurrence)
54
What are the three causes of keloid scars?
1. Genetic factors (highest rates in African/Asian ethnicity)
2. Endocrine factors
3. Excess tension on wound or delayed closure (e.g. burn wounds)
55
Define "spread scar".
A spread scar is characterised by having the exactly same order of collagen fibres as normal scars. It is typically **flat**, **wide**, and often **dented**. Treatment is with surgical excision and closure.
56
Define "chronic wound".
A chronic wound fails to achieve primary wound healing within **4 to 6 weeks**. Common chronic wounds include **diabetic**, **pressure**, and **venous** **stasis** **ulcers**. Chronic wounds are treated with meticulous wound care +/- surgery.
57
What is the name of SCC arising in a chronic wound?
**Marjolin's ulcer.**
Arises secondary to genetic changes caused by chonic inflammation. Always consider a biopsy of a chronic wound.
58
What are the three types of wound healing?
**Primary intention**
* _Definition:_ wound closure by direct approximation of wound edges within hours of wound creation.
* _Indication_: recent (\<6 h); clean wound.
* _Contraindications_: bites (except on face); crush injury; infection; \>6-8 h since injury; retained FB
**Secondary intention (spontaneous)**
* _Definition_: wound left open to heal spontaneously
* **epithelialisation 1 mm/d** from wound margins
* **contraction** **by myofibroblasts at \<0.75 mm/d**
* granulation
* maintained in inflammatory phase until wound closed
* requires dressing changes
* inferior cosmetic result
* _Indication_: when primary closure not possible or indicated
**Third intention (delayed primary)**
* _Definition_: intentionally interrupt healing process, then close wound **4-10 d post-injury** after granulation tissue has formed and **\<105 bacteria/gram of tissue**
* _Indication_: contaminated; long time since injury; severe crush; significant tissue devitalisation; closure of fasciotomy wounds
* prolongation of inflammatory phase decreases bacterial count and lessens chance of infection after closure
59
Contrast contamination, colonisation, and infection.
**Contamination**: presence of _nonreplicating_ organisms within a wound.
**Colonisation**: presence of _replicating_ organisms within a wound.
**Infection**: greater than _105 microorganisms_ in a wound without intact epithelium; may also be infected with small amounts of a very virulent organism (e.g. GBS).
60
Which organism is the most common cause of necrotising fasciitis?
Group A Strep
61
What are three overarching risk factors for infection?
1. Virulence of infecting organism.
2. Amount of bacteria present.
3. Host resistance (host defenses).
62
A patient presents with an acute (\<24 h) contaminated wound. Describe the steps of treatment.
1. Cleanse and irrigate with NS or RL w/ pressure.
2. Evaluate for injury to underlying structures.
3. Control active bleeding.
4. Debride FB, devitalised tissue, old blood. Surgical debridement as needed.
5. Rx systemic antibiotics for obvious infection. Particularly: wound \>8 h; severely contaminated; bites; immunocompromised; involvement of deeper structures (e.g. joints, fractures).
6. +/- Tetanus.
7. +/- post-exposure tx of hep B, HIV, hep C (if titres confirmed at 6 mo).
8. Re-evaluate in 24-48 h for signs of superficial or deep infection.
* If evidence of infection, remove sutures to open infected portion, swab for c&s, irrigate, allow healing by 2ndary intention.
63
A patient comes in with a contaminated wound that has been present for \>24 h. How would you manage it?
1. **Irrigate and debride.**
* Remove particles that could cause traumatic tattooing.
2. **Systemic abx** if concern for worsening infxn (e.g. redness, welling, pain, clinically unwell).
3. **Topical antimicrobials**: beneficial for minor wounds, but doesn not add to systemic abx; may help with chronic wound healing.
4. **Closure via secondary intention** (most common), tertiary closure, skin graft, or skin flap.
* Successful closure depends on **bacterial count \<105/cm3 **prior to closure and **frequent dressing changes**.
64
What is a "biofilm"?
A biofilm is defined as “an assemblage of microbial cells that is irreversibly associated with a surface and enclosed in a matrix of primarily polysaccharide material".
65
What factors increase the risk of contracting tetanus?
**Wound characteristics**
**Tetanus-Prone**
**Not Tetanus-Prone**
Time since injury
\>6 h
\<6 h
Depth of injury
\>1 cm
\<1 cm
Mechanism of injury
Crush, burn, gunshot, frostbite, puncture through clothing, farming injury
Sharp cut (e.g. clean knife, clean glass)
Devitalised tissue
Present
Not present
Contamination (e.g. soil, dirt, saliva, grass
Yes
No
Retained foreign body
Yes
No
66
When is tetanus required for clean, minor wounds? When is it required for all other wounds?
**Clean, minor wounds**
**History of tetanus immunization**
**Td or Tdap\***
**Tig\*\***
Uncertain, \<3 doses, or 10 y since booster
Yes
No
3 doses
No
No
\*0.5 mL combined tetanus and diphtheria toxoids +/- acellular pertussis
\*\*Tetanus immune globulin, 250 U given at separate site from Td/Tdap
**All other wounds**
**History of tetanus immunization**
**Td or Tdap**
**Tig**
Uncertain, \<3 doses, or \>5 y since booster
Yes
Yes
3 doses
No
No^
^ Yes, if immunocompromised
67
What are the risks with more frequent dressing changes?
1. Decreased body temp
2. Cost
3. Outpatient inconvenience
4. Contamination
5. Pain
6. Trauma to wound
68
What are the common pathogens of dog and cat bites?
* **Pasteurella multocida**
* Staph aureus
* Strep viridans
69
What two investigations must be carried out when a patient presents with a bite injury?
1. **Radiographs** to r/o FB or fracture.
2. **Wound swab** - culture for aerobic and anaerobic organisms, gram stain.
70
What antibiotic & dose is used to treat dog and cat bites?
**Clavulin** (amoxicillin + clavulanic acid)
**500 mg PO q8h** started immediately
71
What is an important question to ask someone who comes in with an animal bite?
**Could the animal have rabies?**
Consider prophylaxis if unknown animal or animal showing symptoms of rabies.
Three types of rabies vaccines: 1.0 mL IM in deltoid, repeated on days 3, 7, 14, 28.
+/- Rabies Ig: 20 IU/kg around wound, or IM.
72
How are bite wounds treated?
1. **Aggressive irrigation and debridement**, with urgent **surgical exploration of joint** (if involved).
2. **Healing by secondary intention** is mainstay of treatment.
* Only consider primary closure for bite wounds on the face.
3. **Amox-clav 500 mg PO q8h**
* clinda 300 mg PO q6h + cipro 500 mg PO q12h if penicillin allergy
4. **Splint** in functional position (for hand wounds).
5. For animal bites: consider **rabies** and call Public Health if animal status is unknown.
73
What is the position of safe immobilisation ("intrinsic plus") of the hand? Why is it used?
**Wrist extended 20-30 degrees**
**MCP flexed 60-70 degrees**
**IPs fully extended**
**Thumb mid-abduction/extension**
The position of safety helps **prevent contracture of the joints** by:
* extending the wrist takes tension off extensors and keeps them from pulling MCPJ into extension
* stretching out the MCP collaterals in flexion
* stretching out the IP collaterals in extension
74
What is tenodesis function?
**Tenodesis function:** when the wrist is extended the fingers and thumb flex into the palm and when the wrist is flexed the fingers and thumb open.
75
What are the benefits of negative-pressure wound therapy?
**Promotes healing** through the following:
* removes exudate
* reduces bacterial count
* reduces edema
* promotes granulation
* increases perfusion (blood flow)
76
List nine components of the reconstruction ladder (or elevator).
1. Healing by secondary intention
2. Primary closure
3. Delayed closure
4. STSG
5. FTSG
6. Random pattern flap
7. Pedicle flap
8. Tissue expansion
9. Free flap
NPWT can go on different levels of the "elevator".
77
What are two causes of hypoalbuminaemia?
1. Inflammation
2. Inadequate nutritional intake
78
What antibiotic do patients have to be on when they are receiving leech treatment? What organism is the antibiotic covering in particular?
**Aeromonas** bacteria (gram neg anaerobe)
**Ciprofloxacin** 100% effective in studies
79
How does leeching word to decrease venous congestion?
Leeches release a polypeptide called **hirudin** that **inhibits** the thrombin-catalysed **conversion of fibrinogen to fibrin**.
Hirudin also **blocks platelet aggregation** in response to thrombin and may inhibit Factor X.
80
Define "skin graft".
Skin that is harvested from a donor site and transferred to the recipient site and **does not carry its own blood supply**.
81
What pressure is a VAC usually set at for a SG? What about for other wounds?
SG: **-75 mmHg**
Other wounds: **-125 mmHg**
Intermittent VAC = ?improved granulation
82
What is a sign of pseudomonas infection in a wound? Which two topical therapies can be used to treat it?
**Greenish** discolouration.
**Acetic acid** or **silver**.
83
What is an important concept when deciding on the layers in a wound dressing?
**Wet-to-dry** - keeps wound **moisturised** and allows some **mechanical** **debridement**.
84
What are important considerations for skin graft donor site selection?
* size
* hair pattern
* texture
* thickness of skin
* colour
* facial grafts best taken from "blush zones" above clavicle, such as pre/post auricular or neck
* STSG usually taken from inconspicuous areas such as the buttocks or lateral thigh
85
What are the three phases of skin graft "take"?
1. **Imbibition (first 48 h)**
* ****diffusion of nutrients from recipient site
2. **Inosculation (days 2-3)**
* ****vessels in graft connect with those in recipient bed
3. **Revascularisation (days 3-5)******
86
What factors threaten the survival of a skin graft?
* **poorly vascularised bed** (bone, tendon, irradiated tissue, infected wounds)
* **haematoma/seroma** (staples, sutures, splinting, pressure dressings, bolster dressing all used to prevent movement)
* **shearing**
* **bacterial count \>105**
87
Distinguish autograft vs allograft vs xenograft.
* **autograft**: from same individual
* **allograft**: from same species, different individual
* **xenograft**: from different species
88
What is the purpose of Scarpa fascia?
**No purpose**; it is a **vestigial structure** of the **panniculus carnosus** (animals such as horses and dogs can use it still to twitch).
Vestigial mucles of panniculus carnosus: platysma, palmaris brevis, dartos muscle (scrotum), some muscles of facial expression.
89
Compare STSG and FTSG.
**STSG**
**FTSG**
**Definition**
Epidermis + partial dermis
Epidermis + full dermis
**Donor site**
More sites
Sites limited by ability to close primarily
**Healing of donor site**
Re-epithelialisation via dermal appendages in graft and wound edges
Primary closure
**Re-harvesting**
~10 d (faster on scalp)
N/A
**Graft take**
More reliable, better survival (shorter nutrient diffusion distance)
Lower rate of survival (thicker, slower vascularisation)
**Contraction\***
Less primary contraction (less dermis); greater secondary contraction (decreased as graft gets thicker)
Greater primary contraction (more dermis); less secondary contracture
**Aesthetic**
Poor
Good
**Advantages**
Takes well in less favourable conditions.
Can cover larger area.
Can be meshed for greater area, extravasation of blood/serum, and to prevent covering of contaminated material.
Potential for healing in less favourable environment.
Large number of donor sites.
May use on face and fingers
Resists (secondary) contraction.
Better colour match.
**Disadvantages**
Contracts significantly (secondarily).
Abnormal pigmentation.
High susceptibility to trauma.
Requires well-vascularised bed.
Must remove fat from graft before application.
**Uses**
Large areas of skin.
Granulating tissue beds.
Face (colour match).
Site where thick skin or decreased contracture is desired (e.g. finger).
\*Primary: immediate upon harvesting (d/t elastin); Secondary: once place on wound bed and healing has occurred (d/t myofibroblasts).
90
How much of an increase in length can you get with a Z-plasty?
45 degree angle: **50%**
60 degree angle: **75%**
91
What is Parkland's formula?
Formula for fluid resuscitation to achieve haemostasis post-burn injury.
**4 mL X TBSA (%) X body weight (kg)**
50% given in first 8 hours.
50% given in next 16 hours.
92
What is Froment's sign?
Positive test: **flexion of IP joint of thumb** when grasping paper b/w thumb and index.
Indicates: adductor pollicis paralysis d/t ulnar nerve damage.
**Jeanne's sign** occurs when there is simultaneous **MCP extension** d/t additional ulnar nerve damage.
93
How does an ulnar claw form?
Ulnar nerve injury results in **weakened medial lumbricals** at D4 and D5. Loss of function of the lumbricals results in **hyperextension at the MCPJ** and **flexion at the IP joints** ("claw hand").
94
Which intrinsic hand muscles does the ulnar nerve innervate?
* medial two lumbricals
* hyopthenar muscles
* interossei
* adductor pollicis
* FPB (deep head)
95
Which instrinsic hand muscles does the median nerve innervate?
Think "**LOAF**":
Lateral (radial) two lumbricals
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis (superficial head)
96
What causes ulnar paradox?
How does it appear?
Ulnar paradox is a **lesion of the ulnar nerve at the elbow**.
In addition to the intrinsic hand muscles, **FCU** and the **medial two FDP** are paralysed.
Still have **hyperextension at MCPJ** (as with claw hand), but **no flexion at IPJ** as FDP paralysed.
97
What causes hand of benediction?
Which muscles are paralysed?
How can you test for it? What does it look like?
**Cause**: damage to **median nerve**.
All hand **flexors** are paralysed, except medial 2 FDP (innervated by ulnar nerve). Radial 2 lumbricals are also paralysed (as are thenar muscles),
**Test**: ask patient to **make a fist**. If present, index and (possibly) middle finger will not flex at IPJs. Middle finger may flex still due to quadriga effect.
98
What is the quadriga effect?
The **quadriga effect** is characterized by an active **flexion lag** in fingers adjacent to a digit with a previously injured or repaired flexor digitorum profundus tendon.
This can happen in rev amps if the FDP is pulled over the stump.
Named after the four horse-drawn chariot -- if one horse has a shortened lead, then the other three horses' leads will become slack.
99
List the four stages of development of ulcers.
1. **Hyperaemia**: disappears 1 h after pressure removed.
2. **Ischaemia**: follows 2-6 h of pressure.
3. **Necrosis**: follows \>6 h of pressure.
4. **Ulcer**: necrotic area breaks down.
100
What is the medical term for 'trigger finger'?
What is trigger finger?
**Stenosing tenosynovitis****.**
**Definition:** inflammation of synovium causes size discrepancy between tendon and sheath/pulley (most commonly at **A1 pulley**), resulting in **locking** of the thumb or finger in flexion or extension.
101
What are the two common organisms causing cellulitis?
1. Streptococcus pyogenes (GAS)
2. Staph aureus
102
