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Series 1: The Skin · Episode 12, not yet released

The Aesthetic Layer

The Anatomy of Injectables and Resurfacing

36 minutes. 24 references, each checked at source.

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Tetanus and botulism are the same molecular lesion. Tetanus toxin and botulinum toxin type B cleave the same SNARE protein, synaptobrevin, by the same mechanism, and produce opposite diseases, purely because of which neuron each one reaches.

Episode 12 of The Anatomy Purist, Series One: The Skin, the final episode of the series. Dev covers botulinum toxin type A: SNAP-25, the SNARE complex, and the full serotype discriminator. Why onset is one to three days, and why the delay is stoichiometric rather than pharmacokinetic, it is not slow binding. Upper and lower face targets and danger zones, including the corrugator rules with their provenance separated: at least 1 cm above the bony supraorbital ridge and nothing closer than 1 cm above the central eyebrow, both from the licensed product information; and medial to the mid-pupillary line, which is conventional injector teaching derived from the anatomy rather than label text. Eyelid ptosis, and why apraclonidine works through weak alpha-1 agonism on Müller's muscle rather than through its alpha-2 selectivity. Lateral rectus, not inferior oblique, as the cause of diplopia after crow's feet. HA filler injection planes. The Tyndall

Themes from this episode

Practice what you just heard

Two questions on the themes of this episode, free, marked as you go. Then one from the Vault on the same ground.

Question 1 · Applied

Which injection plane is safest for malar volumisation, and why?

Answer to see the explanation and the source.

Question 2 · Foundation

What is the molecular mechanism of botulinum toxin type A?

Answer to see the explanation and the source.

From the Vault, on the same theme

Head & Neck: Scalp, Face, Parotid & Facial Nerve · Purist Locked

Elevating a facelift flap over the zygomatic arch, you consider the temporal (frontal) branch of the facial nerve along the classically described line from just below the tragus to just above the lateral end of the eyebrow. In which tissue plane is the branch classically described as travelling just above the arch?

  • AIn the subcutaneous fat, immediately deep to the dermis
  • BBetween the superficial and deep layers of the deep temporal fascia, inside the fat pad
  • CDeep to the deep temporal fascia, on the surface of temporalis
  • DWithin the parotideomasseteric fascia, deep to the SMAS below the arch
  • EWithin the temporoparietal fascia, running close to its deep surface

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References

  1. Blasi J, Chapman ER, Link E, Binz T, Yamasaki S, De Camilli P, Südhof TC, Niemann H, Jahn R. Botulinum neurotoxin A selectively cleaves the synaptic protein SNAP-25. Nature. 1993;365(6442):160-3. PMID: 8103915.
  2. Simpson LL. The origin, structure, and pharmacological activity of botulinum toxin. Pharmacol Rev. 1981;33(3):155-88. PMID: 6119708.
  3. Carruthers JD, Carruthers JA. Treatment of glabellar frown lines with C. botulinum-A exotoxin. J Dermatol Surg Oncol. 1992;18(1):17-21. PMID: 1740562.
  4. Nestor M, Cohen JL, Landau M, Hilton S, Nikolis A, Haq S, Viel M, Andriopoulos B, Prygova I, Foster K, Redaelli A, Picaut P. Onset and duration of abobotulinumtoxinA for aesthetic use in the upper face: a systematic literature review. J Clin Aesthet Dermatol. 2020;13(12):E56-E83. PMID: 33488922.
  5. BOTOX / BOTOX Cosmetic (onabotulinumtoxinA) US Prescribing Information. 2024. §2.3, Glabellar Lines. Available from the FDA Drugs@FDA label repository.
  6. Khan S, Pathak G, Milgraum D, Tamhankar M, Milgraum S. Double vision due to lateral rectus injury after cosmetic botulinum toxin injections. Australas J Dermatol. 2023;64(3):e220-e223. PMID: 37386928.
  7. Wijemanne S, Vijayakumar D, Jankovic J. Apraclonidine in the treatment of ptosis. J Neurol Sci. 2017;376:129-32. PMID: 28431598.
  8. Scheinfeld N. The use of apraclonidine eyedrops to treat ptosis after the administration of botulinum toxin to the upper face. Dermatol Online J. 2005;11(1):9. PMID: 15748550.
  9. Rohrich RJ, Pessa JE. The fat compartments of the face: anatomy and clinical implications for cosmetic surgery. Plast Reconstr Surg. 2007;119(7):2219-27. PMID: 17519724.
  10. Rootman DB, Lin JL, Goldberg R. Does the Tyndall effect describe the blue hue periodically observed in subdermal hyaluronic acid gel placement? Ophthalmic Plast Reconstr Surg. 2014;30(6):524-7. PMID: 25192332.
  11. Beleznay K, Carruthers JDA, Humphrey S, Jones D. Avoiding and treating blindness from fillers: a review of the world literature. Dermatol Surg. 2015;41(10):1097-117. PMID: 26356847.
  12. Beleznay K, Carruthers JDA, Humphrey S, Carruthers A, Jones D. Update on avoiding and treating blindness from fillers: a recent review of the world literature. Aesthet Surg J. 2019;39(6):662-74. PMID: 30805636.
  13. DeLorenzi C. Complications of injectable fillers, part 2: vascular complications. Aesthet Surg J. 2014;34(4):584-600. PMID: 24692598.
  14. DeLorenzi C. New high dose pulsed hyaluronidase protocol for hyaluronic acid filler vascular adverse events. Aesthet Surg J. 2017;37(7):814-25. PMID: 28333326.
  15. Paap MK, Milman T, Ugradar S, Silkiss RZ. Assessing retrobulbar hyaluronidase as a treatment for filler-induced blindness in a cadaver model. Plast Reconstr Surg. 2019;144(2):315-20. PMID: 31348334.
  16. Paap MK, Milman T, Ugradar S, Goldberg R, Silkiss RZ. Examining the role of retrobulbar hyaluronidase in reversing filler-induced blindness: a systematic review. Ophthalmic Plast Reconstr Surg. 2020;36(3):231-8. PMID: 31880685.
  17. Hayreh SS, Zimmerman MB, Kimura A, Sanon A. Central retinal artery occlusion. Retinal survival time. Exp Eye Res. 2004;78(3):723-36. PMID: 15106952.
  18. Hetter GP. An examination of the phenol-croton oil peel: Part I. Dissecting the formula. Plast Reconstr Surg. 2000;105(1):227-39. PMID: 10626996.
  19. Rubin MG. Manual of Chemical Peels: Superficial and Medium Depth. Philadelphia: Lippincott Williams & Wilkins; 1995.
  20. Brody HJ. Chemical Peeling and Resurfacing. 3rd ed. Ch. 2, Depth of injury. *[Textbook, edition details to be confirmed against physical copy: publisher, place and year of publication not verified.]*
  21. Manstein D, Herron GS, Sink RK, Tanner H, Anderson RR. Fractional photothermolysis: a new concept for cutaneous remodeling using microscopic patterns of thermal injury. Lasers Surg Med. 2004;34(5):426-38. PMID: 15216537.
  22. Fitzpatrick TB. The validity and practicality of sun-reactive skin types I through VI. Arch Dermatol. 1988;124(6):869-71. PMID: 3377516.
  23. Ablative laser resurfacing. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. NCBI Bookshelf ID NBK557474.
  24. Standring S, ed. Gray's Anatomy: The Anatomical Basis of Clinical Practice. 42nd ed. Elsevier; 2020. Ch. 29 (Face and scalp), Ch. 32 (Nose), Ch. 41 (Orbit), Ch. 4 (Autonomic nervous system).
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