Practical Pearls

Surgical Deroofing for Hidradenitis Suppurativa

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Hidradenitis suppurativa can present in varying degrees of severity; management often poses a challenge for primary care physicians and dermatologists. Deroofing is a surgical technique that has shown superiority over standard excision. We describe the deroofing procedure and review clinical data to provide instruction and support its use.



Practice Gap

Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition characterized by inflammatory nodules, abscesses, sinus tracts, fistulae, and scarring, mainly in intertriginous areas. The extent of disease—classified using the Hurley staging system (stages I–III)—helps guide treatment, which includes medical management and surgical intervention in later stages.

First-line treatment of HS includes topical or systemic medications, or both. Surgical therapy typically is reserved for refractory HS in moderate to severe disease (Hurley stages II and III) and is combined with pharmacotherapy. Specifically, clinical management guidelines issued by an expert committee of the United States and Canadian Hidradenitis Suppurativa Foundations recommend excision or deroofing for recurrent nodules and tunnels.1

Surgical options for HS that are available to the outpatient dermatologist include incision and drainage, electrosurgery, CO2 laser evaporation, excision, and deroofing (also known as unroofing).2 Deroofing is a fairly novel therapy; many dermatologists are unfamiliar with the procedure. A PubMed search of articles indexed for MEDLINE related to HS prior to 2010 revealed only 1 article containing the word deroofing and only 4 articles containing unroofing.

The pathophysiology of HS has important implications for successful treatment. Inflammation of the follicular pilosebaceous unit along with follicular occlusion create challenges with treatment.3 It is postulated that a defect in the glassy membrane of the infra-infundibular wall predisposes the pilosebaceous follicle to lose its structural integrality as pressure builds from plugging of the duct,4 which can result in the clinical hallmarks of HS including tunneling tracts, bridging nodules, abscesses, and fistulae that form with lateral expansion of the plugged follicle.

Leaking of the contents of these plugged follicles into surrounding tissue produces an inflammatory response in characteristic HS lesions. Because debris within the lesions moves laterally instead of being able to burst to the surface, the lesions have difficulty fully healing. Unroofing the lesions and removing built-up debris allows them to heal more expediently and quiets the underlying immune response by removing the stimulus.4

Herein, we describe the benefits, risks, and surgical process of deroofing for HS.

Technique and Tools

Deroofing is performed under local anesthesia, stepwise as follows:

1. Identify sinus tracts and infiltrate the area with lidocaine (Figure, A).

2. Use a blunt probe to define the borders of the area to be unroofed and to evaluate for any communicating sinus tracts (Figure, B).

3. Remove the roof of underlying abscesses and tracts, using a probe as a guide (Figure, C).

4. Enter through the skin or sinus opening using electrocautery or with a scalpel or scissors; perform blunt dissection.

5. Reflect back the entirety of skin overlying the probed areas and remove the skin to expose the base of the lesion (Figure, D).

6. Explore the exposed base and walls of the lesion with the probe again to assess for hidden tracts; take care not to create false tracts.

7. Debride the surgical wound using curettage or rough gauze grattage to remove remaining inflammatory debris or biofilm. To achieve hemostasis, apply aluminum chloride or ferric chloride. Coat the wound with petroleum jelly and gauze and allow it to heal by secondary intention.

8. Educate the patient on wound care—once-daily gentle cleansing with soap and water, followed by application of a moist dressing—which is similar to wound healing by secondary intention from other causes.2,4

Axilla affected by hidradenitis suppurativa with an area of prior deroofing

A, Axilla affected by hidradenitis suppurativa with an area of prior deroofing. New sinus tracts have formed peripherally and have been mapped out. The area has been infiltrated with lidocaine in preparation for deroofing. B, A blunt probe is used to define borders of the area to be unroofed by gently probing sinus tracts for communicating channels. An electrocautery device is used to cut and coagulate, using the probe as a guide. C, Gradually, areas are unroofed by cutting along the guiding probe, with caution to avoid creating iatrogenic sinus tracts. D, Skin overlying the probed area is reflected back and removed, exposing the base of the lesion. Grattage is used to gently debride the base. The electrocautery device can be used to stop any bleeding from unroofed areas.


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