1
Q
What muscle opens the eye? What CN innervates it?
A
- Levator palpebrae superioris
- Innervated by CN III
2
Q
What CN innervates each of the following extraocular muscles?
- Medial rectus
- Lateral rectus
- Superior rectus
- Inferior rectus
- Superior oblique
- Inferior oblique
A
Mnemonic: LR6SO4R3
Lateral rectus = CN VI
Superior oblique = CN IV
Rest of the muscles: CN III
3
Q
What is the function of each of the following extraocular muscles?
- Medial rectus
- Lateral rectus
- Superior rectus
- Inferior rectus
- Superior oblique
- Inferior oblique
A
- Medial rectus = adducts
- Lateral rectus = abducts
- Superior rectus = upward gaze
- Inferior rectus = downward gaze
- Superior oblique = incyclotorsion
- Inferior oblique = excyclotorsion
4
Q
What pharyngeal arch do the muscles of facial expression originate?
A
Second pharyngeal arch
5
Q
Lower, middle and upper facial muscles originate from what embryonic structure?
A
- Lower face muscles: embyronic platysma; do NOT have bony insertions
- Upper and middle facial muscles: embryonic sphincter colli profundus muscle; have bony insertions
6
Q
True or false:
The supraorbital foramen (of CN V1) can be palpated along the orbital rim and the midpupillary line.
A
True
Inject perpendicular to skin at orbital rim at midpupillary line to numb forehead and frontal scalp
7
Q
Where is the infraorbital nerve (of CN V2) foramen located?
Describe the cutaneous and intraoral approach for anesthesia.
What would be numbed?
A
- Cutaneous approach: inject 1 cm inferior to orbital rim at midpupillary line
- Intraoral approach: inject between first and second upper premolars angling needle toward midpupillary line
- Numbs medial cheek, upper lip and nasal ala
8
Q
How would you perform a mental nerve (of CN V3) block?
Describe the cutaneous and intraoral approaches.
What would be numbed?
A
- Cutaneous approach: Inject perpendicular to skin at midpupillary line (2.5 cm lateral to the midline) and 1 cm inferior to the lower second premolar
- Intraoral approach: inject between the first and second lower premolars
- Numbs lower lip and portions of chin
9
Q
How would you perform a supratrochlear nerve (of CN V1) block?
What areas of the face would be numbed?
A
- Inject perpendicular to skin at junction of glabella and medial eyebrow
- Numbs mid forehead, glabella and frontal scalp
10
Q
Describe the approach to a median nerve block.
What tendon is your landmark? Where do you inject?
A
- Find palmaris longus tendon by touching thumb to last two digits of hand with wrist slightly flexed
- Median nerve is between palmaris longus and flexor carpi radialis tendons
- Inject to radial side of palmaris longus tendon at proximal wrist crease
11
Q
Describe the approach to an ulnar nerve block.
What tendons are landmarks? Where do you inject?
A
- Touch thumb to last two digits of hand with wrist turned in a slightly ulnar direction to identify palmaris longus and flexor carpi ulnaris tendons
- Inject radial to flexor carpi ulnaris tendon at proximal crease of wrist at ulnar styloid process
12
Q
Describe how to perform a posterior tibial nerve block.
What areas are made numb by this?
A
- Palpate posterior tibial artery near medial malleolus - nerve is lateral to artery
- Inject into groove between medial malleolus and Achilles tendon
- Numbs heel and middle of the sole of foot
13
Q
Describe how to perform a sural nerve block.
What areas are made numb by this?
A
- Inject into groove between lateral malleolus and Achilles tendon
- Numbs fifth toe and lateral side of sole of foot
14
Q
Describe how to perform a deep peroneal nerve block.
What areas are made numb by this?
A
- Ask patient to dorsiflex against resistance to visualize extensor hallucis longus tendon → inject lateral to this tendon down to bone
- Another approach is to inject subcutaneously between first and second toes
- Numbs skin between first and second toes
15
Q
Describe how to perform a saphenous and superficial peroneal nerve block.
What areas are made numb by this?
A
- Inject anesthestic subcutaneously from malleolus to malleolus on dorsal surface of foot
- Numbs instep and medial ankle (saphenous nerve), and skin of toes other than outside of fifth toe (sural nerve) and in between first and second toes (deep peroneal nerve)
16
Q
Describe how to find Erb’s point.
What nerves arise from here? What would nerve injury lead to?
A
- Draw an imaginary line from the angle of the jaw to the mastoid process.
- From the midpoint of this line, drop a perpendicular line down 6 cm, which will intersect with the posterior border of the sternocleidomastoid muscle.
- The cervical plexus emerges (lesser occipital, great auricular, transverse cervical and supraclavicular nerves)
- CN XI (spinal accessory nerve): innervates trapezius muscle → damage can result in winged scapula, shoulder and neck pain, shoulder drop, trapezius atrophy, arm paresthesias, or inability to abduct arm
17
Q
Describe how to find the temporal branch of CN VII.
What could nerve damage lead to?
Where is it most susceptible to injury?
A
- Draw a line from the earlobe to the lateral brow and from the tragus to highest forehead crease
- Damage results in brow ptosis and paralysis of frontalis → inability to elevate forehead
- Note its susceptibility to injury as it crosses temple
18
Q
At the jawline, what nerve is most susceptible to injury?
What can nerve damage result in?
A
- Marginal mandibular nerve → only has one ramus and covered only by skin and platysma, which is a thin muscle
- The marginal mandibular nerve is the facial nerve MOST susceptible to injury for this reason.
- Damage results in drooling and crooked smile
19
Q
Name the branches of the ophthlamic nerve.
A
- Nasociliary
- Frontal
20
Q
What is the sensory innervation to the nasal tip?
A
Anterior ethmoidal nerve (V1)
21
Q
What is innervated by the lesser occipital nerve?
A
Posterior notch of ear
22
Q
Regarding the properties of local anesthetics, what determines the following:
- Potency
- Duration of action
- Ester versus amide
What structural component binds to the sodium channel?
A
- Potency: lipid solubility → aromatic end
- Duration of action: protein binding
- Ester versus amide: intermediate chain
- Amine end binds to sodium channel
23
Q
All anesthetics except what are vasodilating?
A
Cocaine
This is why vasoconstrictors such as epinephrine are often added.
24
Q
What microsomal liver enzyme metabolizes amide local anesthetics?
A
Cytochrome P450 3A4
Therefore, use with caution in liver disease patients
25
In general regarding local anesthetics, which has a shorter duration of action - esters or amides?
**Esters** have a shorter duration of action.
26
True or false: Local anesthetics can be excreted in breast milk.
True
27
What serious adverse effect can prilocaine cause? How does this manifest?
In whom should prilocaine be avoided?
What is the treatment for this adverse effect?
**Methemoglobinemia**
Avoid in children under 1 year old and those with G6PD deficiency
Manifests as cyanosis
Treat with **methylene blue**
28
What life threatening adverse effect can bupivicaine cause?
Cardiac toxicity not preceded by convulsions and not responsive to resuscitation efforts
29
Local anesthetics affect which nerve fibers first?
**C-type fibers and A-delta fibers**
"You may feel pressure but not pain."
They affect A-beta fibers last, which are responsible for pressure.
30
Longest duration WITHOUT epinephrine?
Longest duration WITH epinephrine?
* Longest duration WITHOUT epinephrine: **ropivicaine (2-6 hours)**
* Longest duration WITH epinephrine: **bupivicaine (4-8 hours)**
31
In what conditions is epinephrine absolutely contraindicated?
* Pheochromocytoma
* Uncontrolled hyperthyroidism
32
If a true allergy to an anesthetic agent occurs, what should be given?
Antihistamines and consider epinephrine 0.3 mL 1:1000 subcutaneously
33
What should be given in moderate to severe lidocaine toxicity?
* Diazepam
* Maintain airway
* Respiratory support (in severe toxicity)
34
What does EMLA stand for and what is it made of?
In whom should it be avoided?
How is it usually applied? How long should you wait?
**E**utectic **M**ixture of **L**ocal **A**nesthesia
* Contains lidocaine and prilocaine in oil-in-water emulsion cream
* Caution in infants (methemoglobinemia due to prilocaine), around eye (corneal injury), broken skin, and large surface areas
* Applied under occlusion for up to 1 hour
35
What is another name for LMX?
Is occlusion needed?
In whom should it be avoided?
**L**iposomal **E**ncapsulated **L**idocaine
* Occlusion not needed
* Avoid in **children \< 20 kg with surface areas larger than 100 cm2; mucosal sites** (use benzocaine or tetracaine instead)
36
What are methods to decrease anesthetic injection pain?
1. Use small bore needles
2. Mix anesthetic fresh (makes it less acidic)
3. Alkalinize with sodium bicarbonate
4. Use topical anesthetic or cooling
5. Counter irritate skin around needle entry point
6. Warm lidocaine
7. Inject slowly
8. Re-enter at previously anesthetized sites
37
Which local anesthetic has the shortest duration of action?
Procaine
38
What are the three types of scalpel handles?
1. Bard-Parker
2. Bard-Parker round knurled handle
3. Beaver
39
What type of scissors are these?
**O'Brien**
Used for cutting suture in delicate areas and tight spaces
40
What type of scissors are these?
**Spencer**
Curved blade with notch on one blade at end for suture cutting
41
What is notable about povidone iodine / iodoform?
* Mechanism of action
* Coverage
* Cons
* Directly halogenates microbial proteins to form salts
* Broad antimicrobial activity, including to spores
* **Must completely dry to be bactericidal**
* **Neutralized by blood, sputum**
* Must be washed off to avoid contact dermatitis
* Can cause neonatal hypothyroidism when there is chronic maternal use
42
What is notable about chlorhexidine?
* Mechanism
* Coverage
* Duration of activity
* Cons
* Disrupts microbial cell membranes, precipitating out cell contents
* Broad spectrum coverage, including to viruses and TB
* Residual activity up to 6 hours
* Can cause keratitis, conjunctivitis, and otitis
43
What is notable about hexachlorophene?
* Mechanism
* Coverage
* Cons
* Disrupts microbial cell membranes; bacteriostatic
* Covers **gram + cocci but _nothing else_**
* **Teratogen**
* **Neurotoxicity in infants** as it can be absorbed through skin
44
What is notable about isopropyl alcohol?
* What is the optimal strength/concentration?
* Mechanism
* Cons
* 70% is optimal strength for antiseptic action
* Denatures proteins
* Fastest onset of action
* Flammable, irritant, no residual activity
45
What is the temperature of a steam autoclave?
* 2 Pascals of pressure and 121 degrees Celsius for 15-30 minutes
* Corrosive → can dull sharp instruments
46
Which sterilization method should be used for heat- and moisture-sensitive instruments?
Gas sterilization
47
What is suture memory a function of? (3)
1. Elasticity
2. Plasticity
3. Diameter
48
Name the best and worst suture types in terms of tissue reactivity and initial tensile strength for absorbable and nonabsorbable sutures.
49
Why is silk used on mucosal surfaces?
Knot security, pliability and ease of handling, despite increased tissue reactivity
50
What is the difference between elasticity and plasticity?
* Elasticity: snaps back into place after swelling ("poliglecaprone 25 has high elasticity")
* Plasticity: stretches and stays without breaking
51
What are treatment modalities for BCCs?
* ED&C
* Excision
* MMS
* Radiation
* Cryotherapy
* Topical imiquimod and 5-FU
* Intralesional interferon alpha
* PDT
* Vismodegib (inhibits sonic hedgehog signaling pathway by binding to smoothened receptor; belongs to 2-arylpyridine class)
52
What is the pathogenesis of BCCs?
* Inactivation of patched (PTCH) tumor suppressor gene
* Activation of smoothened (SMO) or hedgehog (SHH) genes
* Mutations in CDKN2A or point mutations in p53
53
What are genetic syndromes associated with BCCs? (7)
1. Gorlin syndrome (nevoid basal cell carcinoma syndrome)
2. Bazex-Dupre-Christol syndrome
3. Rombo syndrome
4. Brooke-Spiegler syndrome
5. Schopf-Schultz-Passarge syndrome
6. Linear unilateral BCC syndrome
7. Xeroderma pigmentosum
54
A 2.4 cm BCC on the thigh should be treated with what modality?
MMS as it is \> 2 cm
55
What is the risk of developing a second BCC within five years of the first?
40% within five years
56
What is the most common tumor to arise in a nevus sebaceous?
SPAP
57
What is the rate of metastasis of a SCC of the lip and ear?
* Lip: ~13%
* Ear: ~11%
58
What type of UVR promotes photocarcinogenesis, such as in a SCC?
What tumor suppressor genes can become inactivated?
UVB
* Can inactivate p53, p16, and p14
59
What genes can be mutated in PUVA-associated SCC? (2)
* p53 (tumor suppressor gene)
* Ras proto-oncogene
* Risk increases after 250 treatments
60
What particular biologic has been linked to increased risk of SCC?
What melanoma chemotherapy has been associated with eruptive keratoacanthomas as a side effect?
* Etanercept
* Vemurafenib
61
What type of NMSC is discoid lupus associated with?
SCC
62
Is an oral retinoid effective in preventing SCCs?
Yes, acitretin
63
Which of the following is more important for the development of BCCs, SCCs, and melanomas, respectively?
* Chronic sun exposure
* Intermittent high intensity sun exposure
* Chronic sun exposure → SCCs
* Intermittent high intensity sun exposure → BCCs
64
What is the mechanism of action of imiquimod?
TLR-7 inhibitor
65
What is the mechanism of action of 5-FU?
Thymidylate synthase inhibitor, blocking the synthesis of the pyrimidine called thymidine
66
Can PDT be used to treat:
* AK?
* SCCis?
* iSCC?
* AK: Yes
* SCCis: Yes
* iSCC: No
67
What gene is associated with familial melanoma?
**CDKN2A**
* Encodes p16 (required for cell cycle arrest) → negative regulator of Rb pathway
* Encodes p14 → negative regulator for p53 pathway (loss of p14 function decreases p53 function, leading to enhances survival of altered cells)
68
Half of all melanomas harbor a mutation in what oncogene?
**BRAF V600**
A protein kinase within RAS-RAF signaling pathway that plays role in cell growth and proliferation
69
What is the risk of developing a second melanoma after the first?
3.5-4.5%
70
What are examples of adjuvant therapies for metastatic melanoma?
* Interferon alpha
* Ipilimumab (CTLA-4 receptor antibody)
* Vemurafenib (BRAF inhibitor; used in BRAF V600E positive melanoma patients)
* PD-1 and PDL-1 inhibitors (e.g., nivolumab and pembrolizumab)
* MEK (mitogen-activated protein kinase kinase) inhibitors
* Dacarbazine
* Temozolomide
* High-dose IL-2
71
What is the most common type of melanoma?
Where are the most common locations for this subtype among men and women?
**Superficial spreading melanoma** (70% of all melanomas)
* Location: trunk (men) and legs (women)
72
Patients with nevus of Ota may be at higher risk of what type of melanoma?
Uveal melanoma
73
What type of melanoma does not have a radial growth phase?
Nodular melanoma
74
When should sentinel lymph node biopsy be considered?
Breslow depth \> 0.8 cm or \< 0.8 cm with ulceration
75
How often should a patient with newly-diagnosed melanoma be screened with a TBSE?
* q3 months for 2 years,
* q6 months for 3 years,
* Then annually
76
What type of electrosurgery causes collateral tissue damage?
Electrocoagulation
77
What temperature is needed for keratinocyte destruction?
-20 to -30 degrees Celsius
78
"*Fusiform* is a more accurate way to describe an elliptical shape."
79
What is an M-plasty used for?
Decrease scar length so as to not interfere with a free margin
80
What are the stages of healing after graft placement?
1. **Imbibition**: day 1
2. **Inosculation**: day 2-3
3. Epidermal proliferation: day 4-8
4. **Neovascularization:** day 7
5. Sensory nerve restoration: day 14 and beyond
81
When is the earliest that dermabrasion of a skin graft can occur?
4-6 weeks after skin grafting
82
What is a composite graft?
* What are the four stages of composite graft "take"?
A modified full thickness skin gtaft of skin plus cartilage, fat or perichondrium
* Usually used for repair of full thickness alar rim defects using ear helical rim or crus
* Four stages of graft take:
1. Initially graft blanches
2. Turns pale pink by 6 hours
3. Turns dusky blue by 24 hours (venous congestion)
4. Turns pink by day 7, indicating graft survival
83
What is the treatment for chondritis or perichondritis of a donor site for a free cartilage graft?
* Cool compresses
* NSAIDs
84
What is wound strength at the following points after surgery?
* 2 weeks
* 1 month
* 1 year
* 2 weeks: 3-5% normal wound strength
* 1 month: 35%
* 1 year: 80%
85
What is an axial pattern flap?
* How many stages are needed?
* When does pedicle division typically occur?
* What are two examples of axial pattern flaps?
* Axial pattern flap → flap based upon a named vessel for blood supply
* Require 2 stages for completion
* Pedicle division typically at 3 weeks
* Paramedian forehead flap → supratrochlear artery
* Abbé flap → superior or inferior labial artery
86
What are advancement and rotation flaps also known as?
What are transposition flaps also known as?
* Advancement and rotation flaps are also known as "sliding" flaps
* Transposition flaps are also known as "lifting" flaps
87
When a lip wedge repair is performed, what are the four layers involved in the closure?
1. Mucosa
2. Muscle
3. Dermis
4. Epidermis
88
When are mucosal advancement flaps classically used?
What undermining plane is desired?
* Restoring vermillion border
* Undermining takes place deep to minor salivary glands and superficial to orbicularis oris muscle
89
What is a Rintala flap?
* Superiorly based rectangular advancement flap for closure of midline defects of the proximal to mid-nose
90
What is a Peng flap?
* Used to repair central nasal tip defects (modification of Rintala flap)
91
What type of flap is a rotation flap?
Random pattern flap
92
In a rotation flap, what can be used to improve flap mobility and reduce wound tension?
A "back cut"
93
How do you recognize a rotation flap?
Where is the key stitch placed?
A curved line and a linear line
Key stitch at point of maximal tension as in picture
94
Rieger flap
* What are alternative names for it?
* What is it used for?
* The flap is elevated to what level to avoid a deformity?
* Where is the area of pivotal restraint?
* Also known as dorsal nasal rotation flap, Hatchet flap, and glabellar turn-down flap
* Used for medium-sized defects of distal third of the nose
* Flap elevated to level of perichondrium to include underlying nasal musculature to avoid "pig nose" deformity
* Area of pivotal restraint: ipsilateral medial canthus and attachment of nasal musculature to nasofacial sulcus
95
What is a Mustarde flap used for? What kind of flap is it?
Rotation flap of cheek and temple skin to close lower eyelid or infraorbital defect
Avoids wound closure tension along eyelid margin
96
* What is a modified Tenzel flap?
* What is it used for?
* To what level is the flap elevated?
* Combines features of both a rotation and advancement flap
* Used for partial thickness defects of mid to lateral lower eyelid
* Elevated just above orbicularis oris musculature
* Recruits tissue near lateral canthus to avoid ectropion
97
What kind of flap is a transposition flap? How do you recognize it?
A random pattern flap
Look for linear lines that zigzag ("little dipper")
Donor tissue not adjacent to flap, but lifts over intact skin to fit into primary defect
98
What is the difference between a nasolabial transposition flap and a nasolabial interpolation flap?
Both are transposition flaps
Nasolabial/melolabial transposition flap is a one-stage flap
Nasolabial/cheek-to-nose interpolation flap is a two-stage flap
99
What type of flap is a rhombic flap? How can you recognize it?
How many potential closures are there?
Where is the key stitch placed?
A transposition flap (originally described by Limberg)
Looks like a "question mark" or "big dipper"
Has eight potential closures
The secondary defect is closed first with the key stitch.
100
101
What is a DuFourmental flap?
* Modification of rhombic flap
* Narrows angle of tip of secondary defect (i.e., less than 60 degrees) and creates a shorter arc of rotation for flap
* Widened pedicle base, decrease in tip volume, decrease in pivotal restraint at flap base, creating lateral tip tension instead of vertical tip tension
102
In a bilobed flap, what is the order of defect closures?
1. Secondary lobe site (sometimes referred to as tertiary site) closed first
2. Flap sutured into primary defect
3. Trimming and suturing into place of secondary lobe into secondary defect
Make sure to undermine to the nasofacial sulcus
Incise down to periosteum and undermine in submuscular plane (subnasalis)
103
Where is the key stitch of a bilobed transposition flap?
104
How is the bilobed transposition flap designed?
105
For a paramedian forehead flap, what side is the pedicle positioned relative to the wound?
Pedicle positioning is contralateral to the predominant side of the wound to avoid flap torsion causing impaired blood supply
I.e., left-sided nasal defect should utilize a PMFF based on the right supratrochlear artery
106
What is a lip-switch flap?
What is the alternative name for this?
When is this used?
What named artery is it based on?
* An (axial) interpolation flap
* Also known as Abbé flap
* Includes both muscle and mucosa from donor flap
* Best flap for restoring full-thickness tissue and bulk
* Lip defects amenable to Abbé flap are lateral to midline and one-third to one-half of the lip and do not involve oral commissure
* Based on the superior or inferior labial artery (depending on which side the flap is coming from - upper or lower lip)
* Flap divided at 3 weeks per usual
107
If flap dehiscence occurs within 24 hours, what can you do? What if it occurs AFTER 24 hours?
* \<24 hours → okay to resuture
* \>24 hours → often left to heal by secondary intention
108
Ear helix pain one week after surgery may be due to what?
Chondritis (versus infection)
Treatment is NSAIDs
109
Flaps with arterial insufficiency can survive for how many hours? What about venous congestion?
* Arterial insufficiency (i.e., no bleeding after pinprick test) → 13 hours
* Venous congestion (i.e., brisk bleeding of dark blood after pinprick test) → 3 hours
110
What does a z-plasty do? When is it used?
Used for webbing or contraction
Ultimately lengthens the scar
111
What type of "closure" has the lowest rate of infection?
Secondary intention
112
What amount of brow elevation with surgery is acceptable?
Less than 3 mm
Anything more than 2-3 mm usually does not relax back to normal
113
What is a "snap" test?
A test of lid retraction
* Pull lower eyelid away from eye and release
* If "snaps" back, patient has good lid retraction
114
What is a Frost suspensino suture?
Prevents ectropion that may form due to postoperative edema
* Suture placed through the tarsus of lower lid and attached to overlying brow to create suspension sling
* Suture removed in 5-7 days
115
What complication can second intention healing of the medial canthus lead to?
Epicanthal webbing (see photo with bilateral webbing)
116
What is lagophthlamos?
Inability to completely close lid
Can occur due to graft contraction of upper eyelid
117
Which flap has the highest risk of trapdoor effect?
Bilobed transposition flap
118
What is the strength of a scar after 1 month?
35%
119
What is the plane of undermining in a mucosal advancement flap?
Deep to minor salivary glands
Superficial to orbicularis oris muscle
120
What treatment is needed after Mohs surgery of an angiosarcoma?
Adjunctive radiation therapy
121
What are "floaters"?
Tissue on the slide that is not a contiguous part of the specimen being examined
122
How does a MMS slide differ from a permanent section?
Frozen tissue versus paraffin embedded sectioning
123
Should patients stop ASA or anticoagulants prior to MMS?
No
124
How fast do fingernails and toenails grow per month?
How long does it take for fingernail from matrix to grow to distal free edge? What about toenails?
* Fingernails → 3 mm per month and 4-6 months from matrix to free edge
* Toenails 1 mm → per month and 1-1.5 years from matrix to free edge
125
Does the nail matrix have a granular layer?
No
126
What part of the nail matrix forms the dorsal and ventral surfaces of the nail plate?
* Dorsal surface → proximal nail matrix
* Ventral surface → distal nail matrix
Think of a rainbow!
127
What does the lunula represent?
Represents distal component of nail matrix
128
True or false:
Nail bed dermis sits directly atop the periosteum. There is no subcutaneous tissue underneath it.
True
129
Name the instrument
Freer septum elevator
Used for nail avulsion
130
Name the instrument
English anvil action nail splitter
Cutting blade opposite a flat blade
Used for splitting nail plate
131
Name the instrument
Double action nail clipper
Two sharp blades opposed to each other
Cuts thickened nail plates
132
What is the maximum time for tourniquet use on the digit when performing procedures?
15-20 minutes
133
When is epinephrine contraindicated for use in digital anesthesia?
Smoker, vasospastic, peripheral vascular disease, pheochromocytoma, connective tissue disease
134
What is maximum volume of anesthetic per digit during a block?
4 mL
135
When does fingernail development begin? Toenail development?
Fingernails → 10 weeks gestation
Toenails → 14 weeks gestation
136
What part of the nail unit contains melanocytes?
Nail matrix
137
What is the most common tumor of the nail bed?
Glomus tumor
138
How should a biopsy of the nail bed and nail matrix be oriented?
Nail bed → vertically/longitudinally
Nail matrix → horizontally/transversely
139
Visibly split nails after nail matrix biopsy likely involved what portion of the nail matrix?
Proximal nail matrix
Distal nail matrix is lower risk as split nail would be hidden in undersurface of nail
140
Nail plate thickness is related to what aspect of the nail matrix?
The length of the nail matrix affects the nail plate thickness
Horizontal excision of nail matrix can therefore lead to thin nail plates
141
What chemicals can be used for a chemical matricectomy?
Use either 88% phenol or 10% NaOH
After nail avulsion, 88% phenol is applied to nail matrix 2-3 times, then flushed with saline or alcohol
142
What are possible complications after nail surgery?
* Bleeding
* Infection
* Pain
* Pyogenic granuloma
* Reflex sympathetic dsytrophy (pain arising 10 days or more after procedure)
* Osteomyelitis
* Septic arthritis
143
When is trephination indicated?
Hematoma involving \>50% of nail bed
144
What can form if the dermis of proximal nail fold and the open matrix adhere to each other after nail surgery?
Pterygium
145
How deeply do superficial, medium and deep chemical peels penetrate?
* Superficial: epidermis to papillary dermis
* Medium: papillary dermis to upper reticular dermis
* Deep: mid reticular dermis
146
Name the types of superficial peels. (6)
1. Trichloroacetic acid (10-25%) ("TCA")
* Note that ONE coat of 35% TCA can also be considered a superficial peel
2. Jessner's solution
3. Salicylic acid
4. Solid carbon dioxide slush
5. Alpha hydroxy acid (20-70%) ("AHA")
6. Tretinoin solution
147
Do TCA peels "frost"? Do they need to be neutralized?
What can be added to a TCA peel to help treat melasma?
White frosting is common with TCA peels at concentrations \>25%
TCA does NOT need to be neutralized
Add 5% ascorbic acid to reduce tyrosinase activity to treat melasma
148
What comprises 100 mL of Jessner's solution?
* 14 g resorcinol
* 14 g salicylic acid
* 14 g 85% lactic acid
* Ethanol 95% (fill to 100 mL)
149
Do Jessner's solution peels frost? Do they need to be neutralized?
Jessner's solution peels do NOT frost and do NOT need to be neutralized
150
What adverse effects can two of the ingredients in Jessner's solution cause?
1. Salicylic acid → tinnitus
* Fluoresces under Wood's lamp to check for uniform application
2. Resorcinol → syncope and thyroid suppression
151
Do salicyclic acid chemical peels frost? Do they need to be neutralized? What should be considered for darker skin types?
Salicyclic acid peels "pseudo-frost" and do NOT need to be neutralized
Use lower concentrations (20%) in darker skin types
152
What is an example of an alpha hydroxy acid (AHA) chemical peel? What should be done before applying the chemical peel to the skin?
Glycolic acid
Degrease with acetone or alcohol before applying glycolic acid
153
Do alpha hydroxy acid (AHA) chemical peels frost? Do they need to be neutralized? How should they be used in darker skin types?
NO frosting
Neutralized with sodium bicarbonate
Can be used in ALL Fitzpatrick skin phototypes
154
Do tretinoin solution peels frost? Do they need to be neutralized?
Tretinoin solution peels neither frost nor need to be neutralized
155
What does "frosting" represent in a medium depth TCA (35-50%) peel? What affects the degree of frosting that occurs?
Frosting → visible reaction of precipitated protein
* Affected by: degreasing of skin, actinic damage, sebaceous quality of skin, amount and concentration of TCA used
156
What are the two types of deep chemical peels?
1. Phenol
2. Baker/Gordon
157
What are adverse effects of phenol chemical peels?
Renal toxicity and cardiotoxicity
* IVFs are given before and after peel
* Cardiac monitoring during and after peel
* No more than 50% of face can be covered within a 30 minute period
158
What comprises a Baker/Gordon chemical peel? (4)
1. Phenol 88%
2. Distilled water
3. Septisol liquid soap
4. Croton oil
159
What type of collagen fibers are replaced with what other type of collagen fibers after dermabrasion?
Type II collagen fibers → type I collagen fibers as skin heals
160
Which peels do NOT result in frosting? (4)
* AHA (e.g., glycolic acid)
* Tretinoin solution
* Jessner's solution
* Salicylic acid (pseudo-frosting)
161
A patient with a food allergy to strawberries should avoid what type of chemical peel?
Salicyclic acid
"Strawberries contain enough salicylic acid to be a common ingredient found in natural skincare to fight acne."
162
Is desquamation required for a glycolic acid peel to be effective?
No
163
What are the different levels/classifications of frosting? (3)
1. Level I → streaky
2. Level II → frosting with erythema visible through
3. Level III → solid white (papillary dermis penetrated)
164
What are the three commercially available types of botulinumtoxinA.
1. Ona-botulinumtoxinA (Botox)
2. Abo-botulinumtoxinA (Dysport)
3. IncobotulinumtoxinA (Xeomin)
165
* Which TWO neurotoxins must be stored frozen and refrigerated after reconstitution?
* Which ONE is okay to store at room temperature?
* Which ONE is free from complexing proteins?
* Ona-botulinumtoxinA (Botox) and abo-botulinumtoxinA (Dysport) must be stored frozen and refrigerated after reconstitution
* Inco-botulinumtoxinA (Xeomin) is okay to store at room temperature and free of complexing proteins
166
What are contraindications for neurotoxin use?
Myasthenia gravis, Lambert-Eaton syndrome, and ALS
Pregnancy category C
167
What are medications that can enhance the effect of neurotoxins?
Aminoglycosides, calcium channel blockers, and cyclosporine
168
What do the heavy and light chain of type A neurotoxins do?
* Heavy chain → attaches to axon terminals
* Light chain → degrades synaptosome-associated protein 25 kD (SNAP-25)
169
What is the mechanism of action of type A neurotoxins?
Inhibits release of ACh from pre-synaptic motor neurons
* Heavy chain binds to motor neuron
* Botulinum toxin endocytosis occurs
* Light chain inhibits ACh release by SNAP-25
170
What muscle should be injected with neurotoxin type A to address each of the following:
1. Gummy smile
2. Downturned mouth
3. Dimpled chin
1. Gummy smile → levator labii superioris alaeque nasi
2. Downturned mouth → depressor anguli oris
3. Dimpled chin → mentalis
171
What has occurred if brow ptosis happens after neurotoxin injection? Eyelid ptosis?
Brow ptosis → injection too low on forehead
Eyelid ptosis → injection or diffusion into levator palpebrae superioris
Could use Iopidine eyedrops TID for temporary elevation of eyelid/eyebrow of 1-2 mm
172
173
What botulinumtoxin serotype cleaves vesicle-associated membrane protein (VAMP)?
Serotype B
E.g., rimabotulinumtoxinB (Myobloc)
174
A patient reports dysphonia after botulinumtoxin injection. Where was the toxin likely injected?
Orbicularis oris
175
A vial of Botox is reconstituted with 5 mL of saline. How many units are in 0.1 mL?
(100 units per 5 mL) x 0.1 mL = 2 units
176
How long does it take botulinumtoxinA to show efficacy?
3-7 days
177
What is the best way to locate the tail end of the corrugator supercilli muscle?
Make an angry face
1 cm above orbital rim at mid-pupillary line
178
What is the Tyndall effect?
"Blue" nodules resulting from injections with hyaluronic acid filler that are too superficial
179
What are some examples of popular hyaluronic acid fillers? (3)
1. Restylane
2. Juvederm Ultra (and Ultra Plus)
3. Belotero
180
What does the "XC" mean in Juvederm XC?
X-tra comfort
Premixed with lidocaine
181
What are important things to know about polymethylmethacrylate ("PMMA")?
* What is the brand name?
* Is it permanent or not?
* What is needed before injection?
* What are possible adverse effects of PMMA?
1. Also known as "ArteFill"
2. Permanent filler
3. Skin test required 30 days before treatment
4. Place in deep dermis; nodule will form if injected into muscle
5. Granuloma formation possible
182
What is important to know about calcium hydroxylapatite?
* What is brand name?
* Is it temporary, semi-permanent, or permanent?
* How might you incidentally discover someone who has had this filler injected in their face?
* What kind of filler is it considered to be?
* Also known as Radiesse
* Considered "semi-permanent" with duration 9-18 months
* Radio-opaque → visualized on X-ray
* Considered a "stimulatory" filler (i.e., promotes fibroblast-driven collagenation)
* Used for HIV lipoatrophy
183
What are important things to know about poly-L-lactic acid?
* What is the brand name?
* What type of filler is it considered to be?
* What is unique about how it needs to be reconstituted?
* What are important possible adverse effects of poly-L-lactic acid injection?
* Also known as Sculptra
* Considered a "stimulatory" filler (e.g., stimulates fibroblast activity to form new collagen)
* Powder must be reconstituted in sterile water hours to one day prior to injection
* Subcutaneous papules and micronodules can result with superficial injection technique
* Can be associated with an idiopathic immunologic response in immunocompetent patients 9-12 months after injection (sudden onset inflammatory nodules with a cellulitic appearance)
* Used for HIV lipoatrophy
184
What two fillers can be used for HIV lipoatrophy?
185
If arterial injection occurs with a filler, what should be done?
* Warm compresses
* Nitric oxide paste
* Hyaluronidase
* LMWH
* Monitor for blindness, stroke
186
"Laser" is an acronym for what?
* **_L_**ight
* **_A_**mplification by
* **_S_**timulated
* **_E_**mission of
* **_R_**adiation
187
In the most basic sense, how do lasers work?
* Lasers use an energy source to excite a medium (gas, liquid, or solid), producing laser light
* Mirrors within the optical cavity amplify the energy of excited photons
* Excited photos are emitted through a delivery system (e.g., fiberoptic cable or articulated arm)
188
What is monochromicity?
Emission of a single wavelength
189
What is coherence?
* Light waves traveling in phase
* This property allows laser light to be focused to specific spot sizes
190
What is collimation?
* Term used to describe the parallel nature of coherent light waves
* Laser beams emit coherent, collimated light
* Laser beam does not widen much (i.e., remains focused) even when pointed to a greater distance because of this property
191
What is intense pulsed light (IPL)? Is it a laser?
* Filtered flashlamp emits pulses of broad wavelength, divergent light that cannot be tightly focused
* Filters used to focus
192
What is energy? What are its units of measure?
How is energy related to fluence?
* Fundamental unit of work measured in joules (J)
* Energy delivered per unit area is the fluence (J/cm2)
193
What is power? What are its units of measure?
How is it related to "irradiance"?
* Power → rate of energy delivery (i.e., J/sec) measured in watts (W)
* 1 W = 1 J/sec
* Irradiance → power delivered per unit area (W/cm2)
194
What is pulse duration?
How is it related to pulse width?
* Pulse duration → duration of laser exposure measured in fractions of seconds
* Pulse duration and pulse width are the SAME THING!
195
What is spot size?
How does spot size relate to laser beam scatter?
* Spot size → diameter of laser beam on skin surface measured in millimeters
* Larger spot size → decreased laser beam scatter to penetrate deeper
196
What is a chromophore? What are the three chromophores in skin?
* Chromophore → light absorbing molecule
* 3 chromophores in skin → water, hemoglobin, and melanin
197
What is thermal relaxation time (TRT)?
How can it be related to possible collateral tissue damage?
How can TRT be related to the target diameter?
* Thermal relaxation time (TRT) → amount of time required for heated tissue to lose half of its heat
* When pulse duration/width is longer than TRT → heat conducted to surrounding tissue → collateral tissue damage
* TRT ∝ square of target diameter, expressed in seconds
198
What is photomechanical effect?
* Photomechanical effect → when sudden tissue heating by laser beam produces a stress/shock/acoustic wave → results in tissue damage
* "Cavitation" is an example
* Water inside skin is vaporized → steam bubbles expand and collapse
* Causes whitening of treated tattoo
* Mechanism of vessel rupture by pulsed dye lasers
199
What is the overarching principle of laser parameters?
Selective photothermolysis
1. Wavelength of laser must be preferentially absorbed by target (chromophore)
2. Light pulse delivered (i.e., pulse width) must be short enough to affect target but not transfer heat to surrounding tissue
3. Fluence used should be enough to have therapeutic effect but less than the energy that leads to non-specific thermal damage
200
What are the four different wave forms that laser light can be delivered?
1. Continuous wave: constant beam of light with limited peak power
2. Quasi-continuous mode: train of low-energy pulses acting in aggregate like a continuous beam
3. Quality switch mode ("Q-switched"): sudden release of all excited energy from laser medium to produce very short pulse at very high peak power
4. Pulsed wave mode: pulsed light over short period of time producing high peak power
201
Lasers and light sources can cause eye damage.
* Lasers \< 800 nm can affect \_\_\_\_\_.
* Lasers \> 800 nm can affect \_\_\_\_\_.
* Xenon-chloride excimer (308 nm) can damage \_\_\_\_\_, causing \_\_\_\_\_\_.
* What type of laser has the greatest risk of retinal damage?
* Lasers \< 800 nm can affect _retina and choroid_ (target melanin).
* Lasers \> 800 nm can affect _cornea_ (target water).
* Xenon-chloride excimer (308 nm) can damage the lens, causing cataracts.
* Q-switched near-infrared devices pose the greatest risk of retinal damage.
202
Laser wavelengths can be classified in which four broad categories?
1. Ultraviolet (10 - 400 nm)
2. Visible (400 - 720 nm) → including argon, KTP, PDL, and ruby
3. Infrared (720 - 1,000,000 nm)
4. Radiofrequency
203
"Alex is always early at 7:55 a.m."
"Ruby Tuesday on I-694."
204
What is the laser light color for the following laers of the visible spectrum?
1. Argon
2. KTP
3. PDL
4. Ruby
1. Argon → blue-green
2. KTP → green
3. PDL → yellow
4. Ruby → red
205
What laser has the highest efficacy for hair reduction?
What laser is considred the safest for hair reduction in darker skin phototypes (although it is less efficacious)?
* Diode (800 nm) has highest efficacy for hair reduction
* Nd:YAG (1064 nm) considered safest for hair reduction in darker skin phototypes (although less efficacious)
206
What laser can be used for hair reduction in the following situations:
* Dark hair, lighter skin phototypes (2)
* Dark hair, darker phototypes (2)
* Light hair, lighter phototypes (2)
* Dark hair, lighter skin phototypes → Alex (755 nm) and Diode (800 nm)
* Dark hair, darker phototypes → Diode (800 nm) and 1064 nm (NdYAG)
* Light hair, lighter phototypes → Alex (755 nm) and IPL
207
Which tattoo pigment is most amenable to laser tattoo removal?
What tattoo pigment is most associated with allergic reaction?
* Black is most amenable to treatment
* Red is most associated with allergic reaction
208
Why may immediate pigment darkening occur with laser tattoo removal?
* Rust turns black (Fe2O3, ferric oxide → FeO, inferrous oxide)
* White turns to black or blue (Ti4+ in titanium dioxide reduced to → Ti3+)
209
Immediate tissue whitening after tattoo removal laser treatment with Q-switched ruby laser corresponds with what?
Cavitation
Water inside skin vaporized → steam bubbles expand and collapse
210
211
What lasers can be used in superficial pigmented lesions (e.g., ephelides, solar lentigos)? (4)
1. Q-switched ruby (694 nm)
2. Q-switched alexandrite (755 nm)
3. Intense pulsed light (IPL)
4. Q-switched frequency doubled Nd:YAG (532 nm)
212
What resurfacing lasers can be used to treat epidermal nevi? (2)
1. Pulsed CO2
2. Er:YAG
213
What lasers can be used to treat Nevus of Ota, nevus of Ito, and persistent Mongolian spots? (3)
1. Q-switched ruby (694 nm)
2. Q-switched alexandrite
3. Nd:YAG (1064 nm)
214
What laser can be used to treat drug-induced hyperpigmentation from the following agents:
* Amiodarone (1)
* Minocycline (3)
* Amiodarone-induced hyperpigmentation → Q-switched ruby (694 nm)
* Minocycyline-induced hyperpigmentation → Q-switched ruby (694 nm), Q-switched alexandrite (755 nm), or Nd:YAG (1064 nm)
215
What lasers/light-based devices can be used for facial telangiectasias? (3 + 1)
Which 3 of these 4 can be used for poikiloderma of Civatte?
1. KTP
2. PDL
3. Long-pulsed Nd:YAG (for larger vessels near nose)
4. IPL (not a laser)
* KTP, PDL, and IPL can be used for poikiloderma of Civatte.
216
What lasers/light-based devices can be used in the following:
* Striae rubra (2)
* Striae alba (2+1)
* Striae rubra: PDL, Nd:YAG (1064 nm)
* Striae alba: excimer (308 nm xenon chloride), 1550 nm nonablative resurfacing laser, IPL (not a laser)
217
What are the two types of skin resurfacing lasers?
Ablative and non-ablative
218
What are the three types of ablative skin resurfacing lasers?
1. CO2 (10,600 nm)
2. Er:YAG (2940 nm → corresponds to absorption peak of water, 3000 nm)
3. Plasma (using radiofrequency)
219
How do CO2 and Er:YAG compare in terms of the following:
* Recovery period duration
* Risk of post-inflammatory dyspigmentation
* Erythema
* Ability to induce new collagen formation post-operatively
* Recovery period duration → longer with CO2
* Risk of post-inflammatory dyspigmentation → increased with CO2
* Erythema → more with CO2
* Ability to induce new collagen formation post-operatively → better with CO2
220
What are two important infrared lasers?
1. Nd:YAG (1320 nm)
2. Diode (1450 nm)
221
What wavelength range is intense pulsed light (IPL)?
400 - 1200 nm
222
What is fractional resurfacing?
* Columns of ablation with intervening islands of normal skin → grid-like pattern
* Considered non-ablative even though it causes ablative microthermal injury zones
223
What pigments are used to produce red-colored tattoos?
Cinnabar (mercuric sulfide), cadmium selenide, sienna, azo dyes
224
What two lasers could be used to help remove green tattoo ink?
Which ONE laser can be used to treat red, yellow, light brown, violet, and white?
* Green → Q-switched Ruby (694 nm), Q-switched Alexandrite (755 nm)
* Red, yellow, light brown, violet, and white → Q-switched frequency doubled Nd:YAG (532 nm)
225
What injury can be expected with ocular exposure to IPL?
Damage to retina, iris, or uvea
226
At what wavelengths does the absorption spectrum of hemoglobin peak?
Hemoglobin absorption spectrum peaks at 490 nm and 540 nm
227
What is the most effective laser to treat facial telangiectasias?
PDL
228
What medium is used in a KTP laser?
Solid (i.e., potassium titanyl phosphate crystal)
229
Is laser treatment during pregnancy safe?
No
230
What is the gold standard for both anatomic and physiologic assessment of venous disease?
Duplex ultrasound
231
What after sclerotherapy facilitates endofibrosis?
Compression
232
What are the three main categories of sclerosing solutions?
1. Detergent
2. Osmotic
3. Chemical
233
234
What phenomenon can occur after injection of all sclerosing solutions (albeit transiently)?
Localized urticaria
235
What are the two highest risk sites for necrosis with sclerosing agents?
Dorsum of foot and ankle
236
What are the two most common locations for intra-arterial injection with sclerosing solution?
1. Posterior medial malleolus (posterior tibial artery)
2. Popliteal fossa
237
238
What endovenous ablation modalities can be used, such as when reflux is detected at great saphenous vein? (3)
1. Radio-frequency
2. Endovenous lasers targeting hemoglobin (810 nm, 940 nm, 980 nm)
3. Endovenous lasers targeting water (1320 nm, 1450 nm)
Sclerosing solutions are contraindicated when reflux is detected at great saphenous vein.
239
What is the laser wavelength of choice for leg telangiectasias?
Nd:YAG (1064 nm) is #1 choice
Long-pulsed Alexandrite (755 nm), diode, PDL, and pulsed KTP are secondary options
240
What is the best concentration of STS to use to treat venulectasias?
0.3-0.5%
241
What is the advantage of ambulatory phlebectomy compared with sclerotherapy?
Ambulatory phlebectomy is best for large bulging veins → reduced risk of post-inflammatory hyperpigmentation and necrosis
242
What sclerosing solution has the lowest risk of hyperpigmentation?
Chromated glycerin
243
Which sclerosing agent has the highest risk of cutaneous necrosis?
Hypertonic saline
244
What sclerosing agent is contraindicated in a patient taking antabuse?
Polidocanol, PLO (disulfiram-like reaction)
245
Is it legal to use a sclerosing solution that is NOT approved by the FDA?
No, the physician can be prosecuted. Note: this is different than off-label use of an FDA-approved medication.
246
What is the maximum lidocaine dose with tumescent anesthesia for liposuction?
55 mg/kg
35 - 45 mg/kg should be used in lean or older patients
247
Patients should be told to avoid what prior to liposuction?
What type of medication may affect lidocaine metabolism?
Avoid ASA, NSAIDs, vitamin E, alcohol, and herbal remedies for 2 weeks before procedure
Check medication list for CYP450 3A4 inhibitors, which affect lidocaine metabolism
248
Will liposuction improve the appearance of cellulite or skin tone?
No
249
Where do men and women typically store fat?
* Men → flanks
* Women → hips
250
What is the maximum amount of fat that can be extracted at once?
4,500 mL
251
What is the minimum hair density needed at the donor site for hair transplantation?
40 follicular units/cm2
252
What enzyme does finasteride inhibit?
Type II 5-alpha reductase (which converts testosterone → DHT)
253
What type of hair graft is used for eyebrows?
Axillary or pubic hairs
254
Why is it important to avoid sterile water when storing hair grafts?
Dehydration of hair grafts leads to graft death
255
What is the proper depth of hair graft placement?
4-6 mm
256
How do you calculate follicular unit density?
Divide the hair count by the follicle count within a 1 cm2 area
257
What are the most important cells for wound healing?
Macrophages
* Bactericidal, recruit fibroblasts, induce angiogenesis and secrete growth factors
258
What are the three phases of wound healing?
1. Inflammatory
2. Proliferative
3. Remodeling
259
What are examples of hydrophobic and hydrophilic dressings (non-adherent fabrics)?
* Hydrophobic → non-absorbent, occlusive → Vaseline gauze
* Hydrophilic → absorbent, non-occlusive → Adaptic
260
What are examples of antimicrobial dressings? (2)
1. Silver dressings
2. Cadexomer iodine
261
What should be checked prior to recommending compression for venous leg ulcers?
Ankle Brachial Index \< 0.5 → compression contraindicated
262
What are different forms of compression therapy? (6)
1. Unna boot (low absorbency, pressure varies over time)
2. Elastic wrap (single layer → difficult to maintain adequate pressure)
3. Graduated compression stockings (difficult to put on)
4. Four-layer bandage (orthopedic wool → crepe → elastic in figure-of-8 → elastic in spiral; change weekly; absorbent and maintains steady pressure)
5. Orthotics (adjustable; has Velcro)
6. Pneumatic compression (second-line; patient immobilized)
263
What are the 3 steps in the proliferative phase of wound healing?
1. Re-epithelialization
2. Angiogenesis
3. Fibroplasia
264
What is Apligraf?
Skin substitute made from human foreskin
265
What are the 4 stages of pressure ulcers?
1. Stage I → epidermis
2. Stage II → dermis
3. Stage III → subcutaneous
4. Stage IV → muscle and bone
266
What types of dressings should be avoided in infected wounds? (2)
Films and hydrocolloids
267
What dressings are useful in wounds with heavy exudate? (2)
Foams and alginates
268
In what patients should silver sulfadiazine, which otherwise has great antimicrobial coverage, be avoided?
* Sulfonamide allergy
* G6PD deficiency
* Renal or hepatic disease
* Porphyria
* Watch out for leukopenia
269
What dose of cephalexin should be prescribed prior to a procedure involving glabrous skin in high risk patient?
2 g cephalexin 30-60 minutes prior to procedure
270
Is antibiotic prophylaxis needed in a patient with mitral valve prolapse for a basal cell carcinoma excision of the back?
No
271
What prophylactic antibiotic can be given to a patient with a penicillin allergy who is undergoing a procedure of the glabrous skin?
Azithromycin, clarithromycin, or clindamycin
272
What is "Klein's Formula?
The recipe for standard tumescent anesthesia
* 500 mg/L lidocaine
* 0.5 mg/L epinephrine
* 10 mEq/L sodium bicarbonate
Solution should be warmed to 40 degrees Celsius and administered slowly
Up to 55 mg/kg lidocaine can be given using this technique
Surgery CORE
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