Alikhan Flashcards
(161 cards)
1
Q
What are Langer’s lines?
A
Lines along skin that will “gape when punctured with a spike”
Run parallel to underlying muscles (in contrast to relaxed skin tension lines, which run perpendicular to underlying muscles”
2
Q
What are relaxed skin tension lines?
A
Lines that run perpendicular to underlying muscles
Also known as Kraissl and Borges lines
3
Q
What are the important branches of the external carotid artery?
A
- Superficial temporal artery (temple, scalp, lateral forehead)
- Maxillary artery (supplies infraorbital and mental arteries)
- Facial artery (supplies superior and inferior labial arteries)
4
Q
What regions of the face does the superficial temporal artery supply?
A
Temple, scalp and lateral forehead
5
Q
What arteries are supplied by the maxillary artery? (2)
What regions of the face does each of these arteries supply? (2 each)
A
- Infraorbital artery (mid face, nasal dorsum)
- Mental artery (lower lip, chin)
6
Q
What arteries does the facial artery supply? (2)
What regions of the face do these arteries supply? (5)
A
- Superior labial artery
- Inferior labial artery
These supply the upper and lower lips, chin, nasal ala and columella.
7
Q
What is important about the facial artery and filler injection?
A
The facial artery courses medially deep to melolabial fold, giving rise to the angular artery at the base of the ala.
This area is susceptible to intra-arterial injection during filler injection!
8
Q
What branch of the internal carotid artery does the facial artery anastamose with?
A
Dorsal nasal artery (a branch of the internal carotid artery)
Occurs near medial canthus
9
Q
What artery is responsible for most of the facial arteries supplied by the internal carotid artery?
A
Ophthalmic artery
10
Q
What are the important branches of the ophthalmic artery? (9)
What regions of the face do these branches all supply? (4)
A
- Retinal
- Supraorbital
- Supratrochlear
- Infratrochlear
- Dorsal nasal
- External nasal
- Anterior ethmoidal
- Posterior ethmoidal
- Lacrimal
These branches supply the retina, forehead, upper dorsal nose and eyelids.
11
Q
What is the risk of injection of steroids or filler into the glabella?
A
Intraarterial injection of the underlying supratrochlear artery and its anastamoses may occur.
This can lead to skin necrosis or blindness due to communication with the retinal artery.
12
Q
Where do the supratrochlear and supraorbital veins drain?
What is the related “danger triangle”?
A
Drain through orbit into the cavernous sinus
The danger triangle extends from corners of mouth to nasal bridge.
Infections of danger triangle can cause cavernous sinus thrombosis, meningitis and brain abscesses for this reason.
13
Q
Into what lymph nodes do each of the following facial areas drain?
- Forehead, lateral temporal, frontal and periocular areas
- Medial midface
- Lower face
A
- Forehead, lateral temporal, frontal and periocular areas
- Upper jugular nodes
- Medial midface
- Submandibular nodes
- Lower face
- Submental nodes
14
Q
What does SMAS stand for?
A
Superficial musculoaponeurotic system
15
Q
Relative to the superficial musculoaponeurotic system (SMAS), where are motor and sensory nerves located?
A
- Motor nerves are deep to SMAS
- Sensory nerves are superficial to SMAS
16
Q
Sensory innervation of the face is almost entirely supplied by what cranial nerve?
A
CN V (trigeminal nerve)
17
Q
What syndromes can damage to CN V (trigeminal nerve) lead to? (2)
A
- Trigeminal trophic syndrome (classically involving the nasal ala, upper lip or paranasal area)
- Frey’s syndrome (also known as auriculotemporal syndrome; gustatory sweating of facial and periauricular areas with eating)
18
Q
What are the three branches of CN V (trigeminal nerve)?
A
- Ophthalmic (V1)
- Maxillary (V2)
- Mandibular (V3)
19
Q
What are the three major branches of CN V1 (ophthalmic nerve)?
A
- Frontal (two divisions: supraorbital and supratrochlear nerves)
- Nasociliary (three divisions: infratrochlear and anterior ethmoidal nerves)
- Ciliary (supplies lacrimal nerve)
20
Q
What is Hutchinson’s sign?
A
- Involvement of nasociliary branch by VZV
- Presents with distal nasal vesicles and ulcers
- Almost always associated with herpes zoster ophthalmicus!
21
Q
What are the three main divisions of CN V2 (maxillary nerve)?
A
- Infraorbital (includes nasal sidewall, nasal ala and upper lip)
- Zygomaticofacial (malar eminence)
- Zygomaticotemporal (temple and supratemporal scalp)
22
Q
What are the main divisions of CN V3 (mandibular nerve)?
A
- Auriculotemporal (superior portion of anterior external ear, external auditory canal, temple, temporoparietal scalp, TMJ, parasympathetic innervation of parotid gland)
- Buccal
- Inferior alveolar
- Mental (chin and lower lip)
- Lingual (somatic sensation of anterior two-thirds of tongue)
23
Q
What nerve may be injuried with TMJ surgery or parotidectomy?
A
Auriculotemporal nerve
- Can lead to paresthesia of anterior external ear and temple, as well as Frey syndrome
24
Q
What cervical nerves provide the sensory innervation to the following areas?
- Neck, postauricular scalp
- Occipital scalp (majority)
- Lateral neck, angle of jaw, majority of external ear (anterior and posterior portions, and earlobe), postauricular scalp
- Anterior neck
- Anterior chest and shoulder
A
- Neck, postauricular scalp
- Lesser occipital (C2)
- Occipital scalp (majority)
- Greater occipital (C2)
- Lateral neck, angle of jaw, majority of external ear (anterior and posterior portions, and earlobe), postauricular scalp
- Great auricular (C2, C3)
- Anterior neck
- Transverse cervical (C2, C3)
- Anterior chest and shoulder
- Supraclavicular (C3, C4)
25
In decreasing order, name the sensory nerves innervating the ear. (4)
1. **Great auricular** (majority of posterior ear, three-fourths of anterior ear)
2. **Auriculotemporal** (anterior-superior quadrant of ear, external auditory meatus, superior portion of posterior helix)
3. **CNs VII, IX, X** (conchal bowl and external auditory meatus)
4. **Lesser occipital** (posterior notch)
26
A ring block around ear anesthetizes everything except what structures?
Conchal bowl and external auditory meatus
These are innervated by CNs VII, IX and X.
27
What is the maximum volume of anesthetic that can be used in a digital block?
Use 1-2 mL on each side
**Do NOT exceed 8 mL per digit** to avoid tourniquet effect.
Safe to use lido+epi unless patient has underlying vasooclusive disease
28
What nerves provides taste and somatic sensory input to the tongue? (3)
1. Taste: **CN VII** (anterior 2/3) and **CN IX** (posterior 1/3)
2. Somatic sensory: **CN V3** (via lingual nerve, anterior 2/3) and **CN IX** (posterior 1/3)
29
Name the regions of the hand given sensory innervation by the following nerves.
* Ulnar
* Radial
* Median
30
Name the regions of the foot given sensory innervation by the following nerves.
* Deep peroneal
* Posterior tibial
* Saphenous
* Superficial peroneal
* Sural
31
Where does CN VII (facial nerve) emerge from?
What are its 5 branches?
CN VII emerges from stylomastoid foramen, then travels within parotid gland and splits into 5 branches
1. Temporal
2. Zygomatic
3. Buccal
4. Mandibular
5. Cervical
Mnemonic: "To Zanzibar By Motor Car"
32
What muscles are innervated by the **temporal branch of CN VII**? (3)
1. **Frontalis** (eyebrow elevation; horizontal forehead wrinkles)
2. **Corrugator supercilii** (pulls brows inferomedially; scowling appearance, vertical glabellar lines)
3. Upper portion of **orbicularis oculi** (tight closure of eyelids, blinking; "crow's feet")
33
What muscles are innervated by the zygomatic branch of CN VII? (4)
1. Lower portion of orbicularis oculi (for tightly shutting eyelids)
2. Alar portion of nasalis (flares nostrils)
3. Procerus (horizontal glabellar lines)
4. Zygomaticus major (main muscle responsible for smiling)
34
What muscles are innervated by the buccal branch of CN VII? (9)
1. Buccinator (important masticator; keeps food from accumulating between cheek and teeth)
2. Depressor septi nasi (pulls columella toward lip)
3. Transverse portion of nasalis ("bunny lines")
4. Orbicularis oris (important for clear, unmuffled speech)
5. Zygomaticus major and minor (responsible for smiling)
6. Risorius (lesser role in smiling)
7. Levator anguli oris
8. Levator labii superioris ("gummy smile")
9. Levator labii superioris alaque nasi (flares nostril and elevates upper lip)
35
What muscles are innervated by the (marginal) mandibular branch of CN VII? (5)
1. Orbicularis oris
2. Depressor anguli oris (responsible for "RBF")
3. Depressor labii inferioris
4. Mentalis (lower lip protrusion, chin elevation)
5. Upper portion of platysma
36
Why is the **marginal mandibular nerve** at highest risk of permanent motor deficits?
What does such a deficit look like?
* It has only 1-2 rami and is covered by thin skin and platysma only.
* Face appears normal at rest but asymmetric with smiling
* Inability to evert lower lip
* Drooling
37
What muscle is innervated by the **cervical branch of CN VII**? (1)
**Platysma** (depresses lower jaw, tenses neck skin)
Damage could lead to **inability to grimace**.
38
What are possible treatments for vascular occlusion from filler/steroid injection at the **angular artery (base of ala)** or **supratrochlear artery (glabella)**? (3)
1. Nitroglycerin paste
2. LMWH
3. Hyaluronidase (if HA filler used)
39
How does the **temporal nerve** (of CN VII) course?
* Runs diagonally from 0.5 cm below tragus to 1.5 cm above lateral eyebrow
* Superficially located within fascia as it **crosses zygomatic arch**, where it is most susceptible to injury, leading to **unilateral frontalis paralysis and eyelid ptosis**
40
Where is the **marginal mandibular nerve** (of CN VII) most susceptible to injury?
**2-3 cm inferolateral to oral commissure as it passes over mandible**
Leads to facial asymmetry upon smiling, inability to protrude lower lip and drooling
41
Where is **Erb's point**?
**6 cm inferior** to midpoint of imaginary line drawn between **mastoid process and angle of jaw** (along **posterior border of SCM**)
* **Spinal accessory (CN XI), great auricular and lesser occipital nerves** arise here.
42
Damage to the **ulnar nerve at the medial epicondyle of humerus** leads to what "deformity"?
**"Claw-hand deformity"**
* Weakness with wrist flexion
* Loss of flexion of fourth and fifth digits
* Los of sensation in ulnar distribution
43
What is the name of the **most common** scalpel handle?
**Bard-Parker** (standard) handle
44
What is the **name of the scalpel** used for confined spaces or delicate tissue?
**Beaver** handle
45
Name the scissor type.
**Iris scissors**
* Sharp-tipped, short-handled
* Blades may be straight or curved
* Best for sharp dissection
46
Name the scissor type.
**Gradle scissors**
* Similar to iris scissors, but blades are curved and tapered to fine point at tip
* Best for dissection of delicate tissue such as **periorbital skin**
47
Name the scissors type.
**Castroviejo scissors**
* Similar in appearance to **Westcott scissors**
* Good for **delicate eyelid dissection**
48
Name the scissors type.
**Westcott scissors**
* Spring-loaded instrument
* Similar in appearance to **Castroviejo scissors**
* Good for **delicate eyelid dissection**
49
Name the scissors type.
**Mayo scissors**
* **1:1 handle-to-blade ratio**
* Used for **coarse dissection**
50
Name the scissors type.
**Metzenbaum scissors**
* Long handles with blunt tips
* Used for **blunt dissection in areas requiring long reach**
51
Name the scissor type.
| (Pay attention to the handles.)
**Supercut scissors**
* Denoted with **black handles**
* **One blade has a razor edge**
* Supercut blades are available across most scissor types
52
Name the forceps type.
**Adson forceps**
* Relatively large forceps
* Useful for trunk and extremities
53
Name the forceps type.
**Bishop-Harmon forceps**
* Used for **delicate tissues like eyelids**
* Always have **3 holes in handles**
54
Name the forceps type.
**Jeweler's forceps**
* Have **very pointy ends**
* Used for suture removal
55
Name the instrument.
**Periosteal elevator**
* Used to remove periosteum or separate nail plate from nail bed
56
What are the three parts of a surgical needle?
1. **Shank (swage)**: connects needle to suture; weakest part of needle
2. **Body**: strongest part of needle; most common curvature is 3/8 circle
3. **Tip**: can be round (tapered) or cutting
57
When should a **round (tapered)** needle tip be used?
**Deep soft tissues (muscle and fat)**
* Less likely than cutting needles to tear tissues
* Difficult to pass through skin
58
What is the difference between a **conventional cutting** and **reverse cutting** needle point?
* **Conventional cutting**: cutting surface is on inner portion of needle arc (**i.e., facing the wound edge**); **increased risk of sutures tearing through wound edge**
* **Reverse cutting**: cutting surface is on **outer portion** of needle arc; **decreased risk of sutures tearing through wound edge**
59
What type of special knot can be used to tie the end of a running subcuticular suture?
**Aberdeen hitch knot**
60
What is the benefit and risk of **running locked sutures**?
Provides hemostasis but risks strangulation
61
What is the benefit of **vertical mattress sutures**?
**Strongly everts wound edges**
| (**V**ertical = e**V**ert)
62
What is the benefit and risk of **horizontal mattress sutures**?
Provides hemostasis but risks strangulation
Do not use in poorly vascularized areas
63
What is the benefit of **running horizontal mattress sutures**?
**Increased eversion, less strangulation risk**
Improved outcomes relative to simple running sutures, but takes longer
64
What is a **tip stitch**?
**Half-buried horizontal mattress suture**
Best stitch for flap and M-plasty tips
65
What are general suture removal recommendations in terms of days until removal for head/neck and trunk/extremities.
* Head/neck: 7 days or fewer
* Trunk/extremities: 10-14 days
*
66
Regarding absorbable sutures, by what mechanism are the following broken down?
* **Natural fibers**
* **Synthetic fibers**
* **Natural fibers**: digested by **proteolysis**
* **Synthetic fibers**: broken down by **hydrolysis**
Note the absorption rate is increased in moist areas, febrile or protein-deficient patients.
67
How do natural versus synthetic absorbable suture materials compare in terms of degradation mechanism, speed of degradation and inflammatory response?
68
How do monofilament versus multifilament (braided) sutures compare in terms of knot security, coefficient of friction (COF), rates of bacterial infections, capillarity, pliability, memory and inflammatory response?
69
Regarding suture properties, what is "**ease of handling**"?
**Ease with which suture is used**
* **Inversely proportional to memory**
* **Directly proportional to pliability**
Multifilament (braided) sutures have increased ease of handling.
70
Regarding suture properties, what is "capillarity"?
**Ability of suture to absorb/transfer fluid from wound surface to wound**
* Conduit of bacteria
* **Multifilament (braided) sutures have increased capillarity, increasing infection risk.**
71
Regarding suture properties, what is "size" (i.e., **USP size**)?
Diameter of suture material required to achieve a given tensile strength
**More zeroes = smaller suture** (i.e., 6-0 suture is smaller than 5-0 suture)
**Inherent strength of material also affects USP size** (i.e. Prolene is stronger than gut, so 4-0 Prolene is smaller in diameter than 4-0 gut)
72
Regarding suture properties, what is "**tensile strength**"?
**Force required to snap suture**
* Synthetic sutures generally stronger than natural materials
* A suture that has been knotted only has 1/3 of its original tensile strength
73
Regarding suture properties, what is "**coefficient of friction**" (COF)?
**Degree of friction when trying to pull suture through tissue**
* **Increased COF leads to stronger knot security**
* Braided sutures have increased COF
* I.e., polypropylene (Prolene) has very low COF and easily slides through tissue, so more throws are needed to secure knot
74
Regarding suture properties, what is "**pliability**"?
**Ease with which suture can be bent into a knot**
* May be perceived as the suture "**stiffness**"
* **Pliability and memory are two main determinants of suture's "ease of handling"**
75
Regarding suture properties, what is "memory"?
**Tendency of suture to retain original configuration**
* Determined by elasticity, plasticity and suture diameter
* Increased memory leads to decreased knot security and ease of handling
* Monofilament sutures have increased memory versus multifilament (braided) sutures
76
Regarding suture properties, what is "**plasticity**"?
**Ability of suture to retain its tensile strength after being stretched into a new shape**
* Increased plasticity allows suture to stretch to accomodate post-operative swelling without cutting into tissue
* Prolene has increased plasticity relative to nylon
77
What are important components of **fast-absorbing gut** in terms of configuration, tensile strength (50%), absorption and tissue reactivity?
* Configuration: virtually monofilament
* Tensile strength (50%): 3-5 days
* Absorption: 21-42 days
* Tissue reactivity: low
* Often used for skin grafts
78
What are important components of **chromic gut** in terms of configuration, tensile strength (50%), absorption and tissue reactivity?
* Configuration: virtually monofilament
* Tensile strength (50%): 21-28 days
* Absorption: 90 days
* Tissue reactivity: **moderate (but less than plain gut)**
* **Pretreated with chromium salts to slow degradation** (as plain gut degrades within 70 days)
79
What are important components of **polyglecaprone-25** in terms of brand name, configuration, tensile strength (50%), absorption and tissue reactivity?
* Brand name: **Monocryl**
* Configuration: virtually monofilament
* Tensile strength (50%): 7-10 days
* Absorption: 90-120 days
* Tissue reactivity: **minimal**
* Least inflammatory with highest initial tensile strength
80
What are important components of **plain gut** in terms of configuration, tensile strength (50%), absorption and tissue reactivity?
* Configuration: virtually monofilament
* Tensile strength (50%): 7-10 days
* Absorption: 70 days
* Tissue reactivity: **moderate to high**
81
What are important components of **silk** in terms of configuration, ease of handling, tissue reactivity and common use?
* Configuration: **braided**
* Ease of handling: **gold standard** (#1)
* Tissue reactivity: High (second only to #1: plain gut)
* Used on mucosal surfaces
82
What are important components of **polypropylene** in terms of brand name, configuration, tissue reactivity and common use?
* Brand name: **Prolene**
* Configuration: monofilament
* Tissue reactivity: **least inflammatory nonabsorbable suture** (note that polyglecaprone-25 or Monocryl is the least inflammatory absorbable suture)
* Enhanced plasticity allows it to stretch with post-operative swelling rather than cut into tissue
83
What are important components of **nylon** in terms of brand name, configuration, tissue reactivity and common use?
* Brand name: **Ethilon (**or Dermalon)
* Configuration: monofilament
* Tissue reactivity: very low
* Clear nylon can be used as a permanent deep suture for periosteal tacking or prevent scar spread
84
Arrange the following absorbable sutures in terms of time required to decrease to 50% initial tensile strength from most to least. What is most and least?
* Polyglecaprone 25 ("Monocryl) and surgical gut
* Polyglyconate ("Maxon") and Polydioxanone ("PDS II")
* Polyglycolic acid ("Dexon") and chromic gut
* Polyglactin 910 ("Vicryl)
* Fast-absorbing gut
**Most to least time to decrease to 50% initial tensile strength suture types**
1. Polyglyconate ("Maxon") = Polydioxanone ("PDS II")
2. **Polyglactin 910 ("Vicryl)**
3. Polyglycolic acid ("Dexon") = chromic gut
4. **Poliglecaprone 25 ("Monocryl") = surgical gut**
5. **Fast-absorbing gut**
85
Arrange the following absorbable sutures in terms of initial tensile strength from most to least. What is most and least?
* Polyglecaprone 25 ("Monocryl)
* Polyglyconate ("Maxon")
* Surgical gut
* Polyglycolic acid ("Dexon")
* Polyglactin 910 ("Vicryl)
* Polydioxanone ("PDS II")
**Most to least initial tensile strength suture types**
1. **Poliglecaprone 25 ("Monocryl")**
2. Polyglyconate ("Maxon")
3. Polydioxanone ("PDS II")
4. **Polyglactin 910 ("Vicryl)**
5. Polyglycolic acid ("Dexon")
6. **Surgical gut**
86
Arrange the following absorbable sutures in terms of absorption time from most to least. What is most and least?
* Polyglyconate ("Maxon")
* Polyglecaprone 25 ("Monocryl) and polyglycolic acid ("Dexon")
* Surgical gut and polyglactin 910 ("Vicryl)
* Polydioxanone ("PDS II")
* Fast-absorbing gut
**Most to least absorption time suture types**
1. Polydioxanone ("PDS II")
2. Polyglyconate ("Maxon")
3. **Poliglecaprone 25 ("Monocryl") =** polyglycolic acid ("Dexon")
4. **P****olyglactin 910 ("Vicryl) = surgical gut**
5. **Fast-absorbing gut**
87
Arrange the following absorbable sutures in terms of tissue reactivity from most to least. What is most and least?
* Polyglyconate ("Maxon") and polyglecaprone 25 ("Monocryl)
* Surgical gut
* Polyglycolic acid ("Dexon") and polyglactin 910 ("Vicryl)
* Polydioxanone ("PDS II")
**Most to least tissue reactive suture types**
1. **Surgical gut**
2. Polyglycolic acid ("Dexon") = **polyglactin 910 ("Vicryl)**
3. Polydioxanone ("PDS II")
4. Polyglyconate ("Maxon") = **poliglecaprone 25 ("Monocryl")**
88
Among **nonabsorbable** suture types, what has the highest and lowest initial tensile strength?
Highest and lowest initial tensile strength suture types
* Highest initial tensile strength: **stainless steel** (#1 overall) and **polyester** (#1 nonmetal suture)
* Lowest initial tensile strength: **silk**
89
Among **nonabsorbable** suture types, what is most and least tissue reactive?
Most and least tissue reactive suture types
* Most tissue reactive: **silk**
* Least tissue reactive: **polypropylene (Prolene)**
90
What is **triclosan**?
An antibiotic coating for sutures that decreases surgery site infections relative to noncoated sutures
91
What are the two categories of tissue adhesives?
How do they compare in terms of time to dry?
In what patients should these be avoided due to allergy?
**Octyl and butyl cyanoacrylates**
* Octyl ("Dermabond")
* Butyl ("Liquiband" and "GluSeal")
* Butyl dries faster than octyl (30 seconds versus 150 seconds)
* Butyl ultimately is more rigid than octyl
* Cannot be used in acrylate-allergic patients
92
What are the three main categories of **afferent sensory fibers**?
1. **C fibers**: diffuse, dull, aching pain
2. **A-delta fibers**: sharp, localized pain and temperature
3. **A-beta fibers**: vibration and light pressure
**A-beta fibers respond slowest to local anesthetic**, so the patient may feel pressure after anesthesia injection.
93
What is the mechanism by which local anesthetics work?
**Reversible inhibition of Na+ influx** blocks nerve conduction
94
What is the difference between **amide** and **ester** anesthetics?
* Where are they metabolized?
* What are allergic reactions commonly due to?
* What are contraindications?
**Amides** have **2 Is** in their name; **esters** have only **1 I**
* **Amides**: metabolized via **CYP 3A4** in _liver_; allergic reactions are rare and usually to **methylparaben preservative**; contraindication: end-stage liver disease
* **Esters**: metabolized via **pseudocholinesterases** in _plasma_; _renally excreted_, **frequent allergic reactions to PABA metabolite**; contraindications: allergy to PABA, pseudocholinesterase deficiency, renal insufficiency
95
What component of an anesthetic's chemical structure affects its **potency and duration of action**?
**Aromatic end**
This affects its lipophilicity as well.
96
The **PABA metabolite** of ester anesthetic agents cross-reacts with what contact allergens?
Mnemonic: "**PPPESTAA**"
* **P**araphenylenediamine (PPD)
* **P**ABA
* **P**ara-aminosalicylic acid
* **E**thyleneiamine
* **S**ulfonamides
* **T**hiazides
* **A**nesthetics (esters)
* **A**zo dyes
97
What component of an anesthetic's chemical structure affects its **onset of action**?
**Amine end**
Hydrophilic end that binds Na+ channels
98
How long does the **full vasoconstrictive effect** take for epinephrine-mixed anesthetic agents?
**7-15 minutes**
99
How do you mix **sodium bicarbonate in lidocaine**?
Add 1 mL of 8.5% sodium bicarbonate to 10 mL of 1% lidocaine with epinephrine (i.e., a 1:10 mix)
100
What is the mechanism by which **sodium bicarbonate** enhances injected anesthesia?
* Raises pH to physiologic level
* Anesthetic remains neutral/uncharged, so it **more rapidly crosses nerve membranes**
* Advantages: **increased speed of onset and decreased injection pain** (due to physiologic pH)
* Disadvantages: **decreased shelf life** because of epinephrine degradation (**1 week only**)
101
What are advantages and disadvantages of mixing **hyaluronidase** with injectable anesthetic?
* Advantages: **increased anesthetic diffusion** and **decreased tissue distortion** from fluid infiltration
* Disadvantages: **decreased duration** and **increased toxicity** (due to increased absorption); **contains contact allergen thimerosal**
102
* What is the maximum dose (mg/kg) of tumescent anethesia?
* How is 1% lidocaine diluted in tumescent anesthesia?
* What are advantages of tumescent anesthesia?
**55 mg/kg**
* **10-fold dilution of 1% lidocaine with 1:100,000 epinephrine** leads to 0.1% lidocaine with 1:1,000,000 epinephrine
* Advantages: **decreased bleeding, increased duration**; avoids complications associated with general surgery
103
Which anesthetic agent has the **fastest onset of action**?
**Lidocaine (\<1 min)**
Anesthetic of choice in pregnant women
104
What is the important potential risk of **prilocaine**?
**Risk of methemoglobinemia**
* Increased risk of G6PD deficiency and in children \<1 years old
* Component of topical EMLA
105
Which anesthetic agent has the **longest duration of action when combined with epinpehrine**?
**Bupivicaine** (Marcaine)
* Duration of action up to 8 hours
* Sometimes added to lidocaine for big Mohs cases to provide long-lasting anesthesia
106
What are two notable risks of **bupivicaine** (Marcaine)?
1. Highest risk of **cardiac toxicity**
2. Risk of fetal bradycardia
107
What anesthetic agent has the **longest duration of action in the absence of epinephrine**?
**Ropivicaine**
* Duration of action of up to 6 hours without epinephrine
* (Bupivicaine has the longest duration of action with epinephrine.)
108
What are the signs/symptosm of mild, moderate, severe and life-threatening lidocaine overdose?
* Mild: metallic taste, **circumoral numbness** ("Happily buzzed and tingly feeling")
* Moderate: **tinnitus, slurred speech** ("Hammered! Can't hear or speak well"
* Severe: seizures, cardiopulmonary depression ("**Severe alcohol poisoning**")
* Life-threatening: coma and cardiopulmonary arrest
109
What is the reversal agent for benzodiazepine overdose?
Flumazenil
110
Sensory innervation of the foot
111
112
113
Landmarks for **median and ulnar nerve blocks**. The tendons can be easily visualized and palpated.
114
115
What hand hygiene agent(s) reduce bacterial counts most?
1. **70% Alcohol or 70% alcohol + chlorhexidine**
2. Chlorhexidine only
3. Iodophors
4. Triclosan
5. Soap
(Note that 70% alcohol is more effective than 100% alcohol.)
116
Where should use of **chlorhexidine** be avoided?
**Eyes** (corneal damage) or **ears** (ototoxic)
* *Serratia* may colonize chlorhexidine bottles, leading to infection
117
What is **topical alcohol** inactive against?
* **Spores (i.e., *C. difficile*)**
* Protozoan oocysts
* Certain nonenveloped viruses
118
What is the longest acting **topical antiseptic**?
**Chlorhexidine**
* \>6 hours
* Remains bound to stratum corneum
119
What are important things to know about the topical antiseptics **chloroxylenol (parachlorometaxylenol)** and **hexachlorophene**?
**Chloroxylenol** is inactive against **Pseudomonas**
**Hexachlorophene is neurotoxic and teratogenic**, so is not used anymore
120
What are important things to know about topical antiseptics **iodine and iodophores**?
* **Very broad spectrum coverage**, including **bacterial spores**
* Can cause skin irritation and discoloration
* **Inactivated by blood and sputum**
* ***_Must wait for it to dry to be effective!_***
121
What are important things to know about the topical antiseptic "**quaternary ammonium compounds**" (e.g., **Benzalkonium**)?
* **Inactivated by organic materials - even cotton gauze**
* Used in **eyedrops**
122
What is important to know about the topical antiseptic **triclosan**?
* **Not as effective** as alcohol, chlorhexidine, or iodophors
* Binds **enoyl-acyl carrier protein reductase** in bacteria to interfere with RNA, fatty acid, and protein synthesis
123
What is important to know about the topical antiseptic **soap and water**?
* Highly effective against **C. difficile** and **Norwalk virus**
* **Most appropriate for soiled hands**
124
What is the mechanism of action of **cryosurgery**?
1. **Extracellular dehydration** due to formation of ice crystals in extracellular space, causing an extracellular hyperosmotic gradient that dehydrates adjacent cells
2. **Membrane rupture** due to intracellular ice crystal formation
3. Initial **vasoconstriction** causes transient anoxia
4. **Compensatory vasodilation** with _thawing_ releases **harmful free radicals**
125
What is the optimal freezing technique with cryotherapy?
**Rapid freezing** + **slow thawing** favors intracellular ice formation
126
What are the optimal parameters of the design of the fusiform excision?
* Apical angles ≤ 30º
* Length : width ratio ≥3 : 1
* Parallel to relaxed skin tension lines
127
In what body areas may a crescent excision (instead of a fusiform excision) be better? (at least 2)
1. Cheek
2. Chin
128
In what body areas may an **M-plasty** (instead of a fusiform excision) be better? (at least 2)
**M-plasty is used to shorten length of excision** so that incision does not extend into an undesired location.
1. Perioral
2. Periocular
129
1. In what body areas is an S-plasty ("lazy S") better than a fusiform excision?
2. What does an S-plasty do to change the properties of the resulting scar?
* **Used on convex surfaces**, such as the **forearm** and **shin**, and for **excisions crossing over a joint**, such as the **elbow** or **knee**
* **Increases total scar length** but linear distance between apices remains the same
* **Redistributes tension** along different vectors, decreasing tension at central portion of scar
* **Decreases scar contraction**
130
* A **lip wedge excision** can be used to repair defects **up to what length** of the lower lip?
* What must be done before defect closure is performed to ensure cosmesis?
* **1/3** of the length of the lower lip
* **Mark vermillion border before closure** to ensure precise realignment
* The lip must be **closed in a layered fashion** in a particular order.
131
**In what order** must the defect resulting from **lip wedge excision** be closed?
1. **Submucosal layer**: use silk or polyglactin 910 (Vicryl) and bury knots away from oral cavity
2. **Orbicularis oris muscle**: use polyglactin 910 to maintain oral sphincter competence (critical step!)
3. **Dermis and subcutaneous tissue**: use polyglactin 910 to reapproximate vermillion-cutaneous border
4. **Epidermis**: use nylon with hypereversion to avoid depressed scar
132
Name the desired undermining plane for the following:
* Cheek
* Ear
* Eyebrow
* Eyelid
* Forehead
* Lateral neck
* Cheek: **mid-subQ plane** → avoids parotid duct, CN VII, vascular structures
* Ear: **perichondrium**
* Eyebrow: **subQ**, deep to hair bulbs
* Eyelid: **immediately above orbicularis oculi muscle**
* Forehead: deep subQ plane **just above frontalis**; occasionally undermine in avascular subgaleal plane for large/deep wounds
* Lateral neck: **superficial subQ plane** → avoids CN XI and Erb's point
133
Name the desired undermining plane for the following:
* Lip
* Mandible
* Nose
* Scalp
* Temple
* Lip: **immediately above orbicularis oris muscle →** avoids cutting into muscle and labial artery branches
* Mandible: **superficial subQ plane** above marginal mandibular nerve
* Nose: submuscular fascia/periosteum/perichondrium (**deep to SMAS/nasalis muscle**) → relatively avascular plane
* Scalp: **subgaleal** → avascular plane
* Temple: **superficial subQ plane** → avoids temporal branch of CN VII and temporal artery
134
What is wound strength at the following post-operative times?
* 1 week
* 2 weeks
* 1 month
* 1 year and beyond
* 1 week = 5%
* 2 weeks = \<10%
* 1 month = 40%
* 1 year and beyond = **80% (maximum strength)**
135
What is the **MMS cure rate** for the following skin cancers?
* BCC/SCC (primary and recurrent)
* DFSP
* MMIS (lentigo maligna)
* **Primary BCC: 97-99%** (vs **93% for WLE**)
* **Recurrent BCC: 90-95%** (vs **80% for WLE**)
* **DFSP (treatment of choice)**: 98-100%
* Otherwise, MMS cure rate is **≥90% for most other skin cancers**.
136
What are **histochemical stains** that can be used for Mohs tissue processing? (2)
1. **H&E** (cell nuclei = blue, cytoplasm and ECM = pink)
2. **Toluidine blue** (cell nuclei = blue, polysaccharides = purple)
137
Regarding flaps, define the following terms:
* Primary defect
* Secondary defect
* Primary flap lobe
* Secondary flap lobe
* **Primary defect**: operative wound requiring repair
* **Secondary defect**: operative wound created by flap elevation and primary defect closure
* **Primary flap lobe**: flap portion covering primary defect
* **Secondary flap lobe**: flap portion covering secondary defect
138
Regarding flaps, define the following terms:
* Pedicle (flap base)
* Flap tip
* Pivot point
* Key stitch
* **Pedicle** (flap base): vascular base of flap → provides blood flow to flap
* **Flap tip**: portion of flap furthest from blood supply/pedicle → **highest risk for necrosis**
* **Pivot point**: point on base of flap around which flap transposes/rotates → **critical to undermine** for flap movement
* **Key stitch**: **critical initial stitch** required to move flap onto primary defect
139
Regarding flaps, define the following terms:
* Axial pattern flap
* Name three on face and their blood supply source
* Random pattern flap
* Name their general blood supply source
* **Axial pattern flap**: flaps based on a **named vessel** in pedicle
* Paramedian forehead flap (supratrochlear artery)
* Dorsal nasal rotation "Rieger" flap (angular artery)
* Abbe cross-lip flap (labial artery)
* **Random pattern flap**: flaps with unnamed musculocutaneous arteries within pedicle; perfused by **anastomotic subdermal and dermal vascular plexuses**
140
On the face, a rotation flap pedicle should be positioned where in relation to the defect?
Flap pedicle should be placed inferolateral to defect to increase lymphatic drainage → avoid flap lymphedema
141
At how many weeks is an **interpolation (two-stage transposition) flap** divided and inset?
3 weeks
142
Name the flap.
| (Key stitch marked with a star)
Burow's advancement flap
143
Name the flap.
| (Key stitch marked with a star)
Crescenteric advancement flap
144
Name the flap.
| (Key stitch marked with a star)
V-to-Y advancement flap
Formerly, "island pedicle flap"
145
Name the flap.
| (Key stitch marked with a star)
Mustarde type rotation flap
146
147
Name the flap type.
| (Key stitch is marked with a star)
Bilobed transposition flap
148
Name the flap type.
| (Key stitch marked with a star)
Nasolabial/melolabial transposition (modified banner) flap
149
What are the **4 phases of graft healing**?
1. **Imbibition** (24-48 hours): passive diffusion of nutrients to graft from plasma exudate of wound bed
2. **Inosculation** (2-3 days, lasts 7-10 days): linkage of dermal vessels between graft and recipient wound bed
3. **Neovascularization** (day 7): occurs in conjunction with inosculation; capillary and lymphatic ingrowth from recipient to graft
4. **Reinnervation/maturation** (≥ 2 months to years)
150
Regarding a FTSG:
* How much should the graft be oversized?
* What is defatting?
* Oversize graft by 10-20%
* Remove adipose tissue on graft (as fat thought to reduce graft survival, which is controversial)
151
Regarding delayed grafting, how long is the wound allowed to granulate before grafting is performed?
1-3 weeks → granulation tissue promotes graft survival
152
What is a **Burow's graft**?
* **FTSG derived from adjacent (discarded) skin**
* Most often used when primary repair does not fully close defect or when defects span two cosmetic units (allows primary closure of one unit and graft of the second cosmetic unit)
153
When does **dermabrasion** of a FTSG take place?
4-6 weeks post-op
154
What should be done to the graft if **graft necrosis** (indicated by black color) occurs?
**Do NOT remove graft** as it serves as a biologic dressing
155
If MRSA surgical site infection is suspected, what are three antibiotics that could be used?
1. Bactrim
2. Clindamycin
3. Doxycycline
156
What is the on differential diagnosis for a surgical site infection?
Contact dermatitis (usually itchy) and inflammatory suture reaction (usually presents later)
157
What is the classic teaching about **resuturing** in the setting of **wound dehiscence** occuring within 24 hours of surgery and \>24 hours?
* Resuture if within 24 hours
* Allow to granulate on its own if \>24 hours
158
What is the treatment for chondritis after surgery?
* May be associated with *Pseudomonas*
* Treat with **NSAIDs and quinolones**
159
How long after surgery do **spitting sutures** and/or **suture granulomas** typically occur?
1-3 months postop
* Remove spitting sutures
* Okay to leave suture granulomas alone as they self-resolve
160
What is the mechanism of action of the following for scar treatment:
* Steroids
* Imiquimod
* 5-FU
* **Steroids**: binding of **nuclear steroid receptor** decreases fibroblast activity and collagen production
* **Imiquimod**: stimulates **IFN-alpha** (increasing collagen breakdown) → decreases **TGF-beta** levels (increased in keloids)
* **5-FU**: blocks **TGF-beta-2 gene** in fibroblasts → decreasing collagen production
161
If a subungual hematoma occurs, what may be considered? (2)
* **Trephination** ("burr holing") indicated if hematoma **\>50% of nail**
* May occur in combination with **fractured distal phalanx → X-rays recommended**
