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Scalp Lacerations – “You Can Leave Your HAT On!”

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You can leave your “HAT” on: An approach to scalp lacerations and review of the hair apposition technique

Resident Clinical Pearl (RCP) – November 2018

Devon Webster – FMEM PGY1, Dalhousie University, Saint John, New Brunswick

Reviewed by Dr. David Lewis

 

Quick case!

Joe Cocker and Randy Newman had an altercation while debating who recorded the best version of “You can leave your hat on”. Randy won (mainly because he is still alive), but unfortunately he sustained a nasty head injury in the process. You deduce that he does not require a CT head but he’s got a 7 cm lac over his scalp. What should you do next?

 

Review of scalp anatomy:

The scalp is divided into 5 layers, which can conveniently be recalled using the mnemonic, SCALP:

  • Skin

    Ref 1

  • dense Connective tissue
  • Aponeurosis
  • Loose connective tissue
  • Periosteum

 

Recall that the dense connective tissue layer is richly vascularized. The tight adhesion of these vessels to the connective tissue inhibits effective vasoconstriction, hence the profuse bleeding often seen with scalp wounds.

The loose connective tissue layer = the DANGER ZONE when lacerated. This layer contains the emissary veins, which connect with the intracranial venous sinuses. Consequently, lacerations reaching this layer are high risk for spreading infection to the meninges

 

 

 

Examining the laceration:

Ref 2

Prior to choosing the most appropriate closure technique, the wound should be cleaned and cleared of debris and the depth of the wound should be determined.

  • Superficial wounds: generally do not gape and have not gone beyond the aponeurosis. Adherence to the aponeurosis should prevent the wound edges from separating.
  • Deep wounds: gape widely due to laceration of the aponeurosis in the coronal plane. Tension secondary to the occipitofrontalis muscles will pull the wound open in opposite directions.

 

Ref 2

(A) Scalp laceration that extends through the aponeurosis
(B) CT showing an associated skull fracture

 

Choosing a closure technique:

A. The HAT technique: Hair Apposition Technique

What it is: A fast and simple technique for superficial laceration closure whereby the physician twists hair on either side of the laceration together and seals the twist with a drop of glue for primary closure. Various advantages, as described below, including no need for follow up suture or staple removal.

When to use it: Consider using HAT for linear, superficial lacerations, <10 cm that have achieved appropriate hemostasis (assuming the patient has hair!).

The evidence for HAT: An RCT based out of Singapore, comparing suturing (n=93) to HAT (n=96) for scalp lacerations <10 cm found HAT to be equally acceptable if not superior to suturing. Patients were more satisfied (100% vs 75%), had less scarring (6.3% vs 20.4%), fewer complications (7.3% vs 21.5%), lower pain scores (2 vs 4), shorter procedure times (5 vs 15 min) and less wound breakdown (0% vs 4.3%) (Ref 4)

A follow up study by the same group assessing cost-effectiveness of HAT compared to suturing found a cost savings of $28.50 USD (95% CI $16.30 to $43.40) in favor of HAT when taking into consideration materials, staff time, need for removal appointments and treatment of complications (Ref 5)

A retrospective observational study comparing HAT (n=37) to suturing (n=48) and stapling (n=49) also found HAT to be superior to both suturing and stapling due to increased patient satisfaction at days 7 and 15, reduced pain, lower cosmetic issues and complication rates (Ref 6)

 

How to do HAT (see diagram):

  1. Choose 4-5 strands of hair in a bundle on either side of laceration
  2. Cross the strands
  3. Make a single twist to appose the wound edges
  4. Secure with a single drop of glue
  5. Advise patient that the glue will eventually come off on its on and no formal removal is required.

Cautions with HAT: avoid getting glue into the wound as it may result in wide scarring with a bald spot (Ref 3)

 

B. Wound Staples

If the HAT technique is not an option (no glue, bald, etc) and the lac is superficial (above the aponeurosis), staples are preferred over suturing due to Ref 3:

  • Rapid closure of wound edges
  • Non-circumferential wound closure avoid potential strangulation
  • No cross hatch marks
  • Less expensive

C. Wound Sutures

Sutures are appropriate for deep, gaping wounds or those requiring immediate hemostasis.

Suture is required for lacerations through the aponeurosis to reduce spread of infection, hematoma formation and increased scarring. Furthermore, inadequate repair of the aponeurosis may result in asymmetric contraction of the frontalis muscle (Ref 3)

 

 

Final thoughts post-closure:

  • White petroleum ointment is as effective as antibiotic ointment in post-procedural care (Ref 7). Furthermore, the next time you consider handing out bacitracin (or polysporin), recall that it was declared ‘contact allergen of the year for 2003’ by the American Contact Dermatitis Society. Bacitracin is among the top ten allergens in the US causing allergic contact dermatitis (Ref 8).
  • Wetting the wound as early as 12 hrs post-repair does not increase the risk of infection (Ref 7). Consider delaying wetting in the case of HAT.

Bottom line:

  • For superficial lacerations, <10 cm with adequate hemostatic control, the hair apposition technique is a fast, cost-effective method of wound closure with high patient satisfaction, reduced pain and lower complications compared to suturing and staples.
  • Lacerations through the aponeurosis require suturing to reduce rates of complications.
  • Consider use of petroleum jelly over antibiotic containing ointments such as polysporin.

 

Video

 

 

References:

 

1 Hunt, W. “The Scalp.” Teachmeanatomy.info. Last updated Oct 24, 2018. Accessed Nov 28, 2018. URL:  https://teachmeanatomy.info/head/areas/scalp/

2 Dickinson, E. Uptodate. Accessed Nov 28, 2018 URL: https://www.uptodate.com/contents/image?imageKey=EM%2F87633&topicKey=EM%2F16696&source=see_link

3 Hollander, J. “Assessment and management of scalp lacerations.” Uptodate. Updated Feb 23, 2018. Accessed Nov 28, 2018. URL: https://www.uptodate.com/contents/assessment-and-management-of-scalp-lacerations

4 Ong ME. “A randomized controlled trial comparing the hair apposition technique with tissue glue to standard suturing in scalp lacerations (HAT study).” Annals of Emergency Medicine. July 2002. 40:1. 19-26.

5 Ong ME. “Cost-effectiveness of hair apposition technique compared with standard suturing in scalp lacerations.” Annals of Emergency Medicine. 2005 Sept; 46(3):237-42.

6 Ozturk D. “A retrospective observational study comparing hair apposition technique, suturing and stapling for scalp lacerations.” World J Emerg Surg. 2013; 8:27.

7 Forsch, R. “Essentials of skin laceration repair.” American Family Physician.

8 Fraser, J. “Allergy to bacitracin.” Dermnet NZ. September 2015. Accessed on Nov 28, 2018 URL: https://www.dermnetnz.org/topics/allergy-to-bacitracin/

 

 Randy:

 

Joe:

 

 

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