Posture
How we use evidence
Evidence is necessary but not sufficient. We use the literature to anchor decisions, clinical judgment to apply them to the patient in front of us, and honest reassessment to change course when something is not working.
This page lists the studies we lean on, summarizes what each one tested, and is explicit about what it does and does not establish. A page that pretends the evidence is settled when it isn't loses the audience it should be earning.
Evidence base
Follicle-directed laser therapy
Long-pulsed Nd:YAG (1064 nm) is the most-studied device in HS. The trials below establish a real effect on lesion burden and a mechanistic basis at the follicular level.
- What it tested
- Long-pulsed Nd:YAG against control (treated vs untreated body sites in the same patient).
- What it found
- Significant reduction in modified Hidradenitis Suppurativa Lesion Area and Severity Index across treated sites.
- What it does not establish
- Single-center, short follow-up, intra-patient design. Establishes a real effect, not long-term durability.
- What it tested
- Long-pulsed Nd:YAG monthly for four months in Hurley I–II HS, with paired untreated control sites.
- What it found
- Statistically significant reduction in disease severity at treated sites versus untreated controls.
- What it does not establish
- Modest sample, four-month treatment window. Does not address Hurley III or established tracts.
- What it tested
- Pre- and post-treatment biopsies of HS-affected skin to characterize histologic changes after Nd:YAG therapy.
- What it found
- Reduction in follicular and perifollicular inflammation and folliculosebaceous unit destruction.
- What it does not establish
- Mechanistic, not outcome-based. Supports why follicle therapy works; does not measure clinical response.
Evidence base
1470 nm intralesional sinus tract closure
The HS-specific evidence base is led by a published technique paper for the 1470 nm intralesional approach, with earlier intralesional-diode precedent at a different wavelength. The durability of the underlying device-and-fiber technique is anchored separately in the pilonidal SiLaC literature, which we present below as a technical analog rather than as a direct HS outcomes claim.
- What it tested
- Intralesional 1470 nm diode laser with radial-emitting fiber for closure of established HS sinus tracts, with a step-by-step technical description.
- What it found
- Published series of intralesional 1470 nm laser treatment of HS sinus tracts report meaningful rates of primary tract healing and durable closure beyond 12 months. Specific outcome figures will be cited once Dr. Kamrava completes review of the underlying references.
- What it does not establish
- Technique paper. Not a head-to-head trial against excisional approaches. Quantitative outcome figures are held until Dr. Kamrava has personally reviewed the full paper.
- What it tested
- Intralesional diode laser delivered via fiber into HS lesions in 20 patients — same mechanistic approach as the 1470 nm technique, at a different wavelength (1064 nm).
- What it found
- Reduction in lesion activity and supportive evidence for the conceptual approach of fiber-delivered intralesional energy in HS.
- What it does not establish
- Different wavelength (1064 nm rather than 1470 nm) and small sample. Cited as supporting precedent for the intralesional concept, not as direct evidence for the 1470 nm device.
Technical analog: pilonidal SiLaC literature
The 1470 nm intralesional radial-fiber technique is well-established in pilonidal sinus disease, where Dr. Kamrava has personally performed several hundred procedures. The published pilonidal SiLaC literature establishes durability, low morbidity, and reproducibility of the underlying technique. HS sinus tract anatomy differs from pilonidal anatomy, so pilonidal outcome rates do not directly transfer — but the device, fiber, energy delivery, and closed-wound recovery model are the same.
- What it tested
- Multicentre cohort of patients treated with SiLaC (1470 nm intralesional radial-fiber) for pilonidal sinus disease.
- What it found
- Closure rates and morbidity profile consistent with a low-morbidity, durable alternative to excisional approaches in pilonidal disease.
- What it does not establish
- Pilonidal anatomy, not HS. The technique transfers; outcome rates do not.
- What it tested
- Outcomes of SiLaC for chronic pilonidal sinus disease in a single-center series.
- What it found
- Supports durability and reproducibility of the SiLaC technique, with a favorable morbidity profile.
- What it does not establish
- Pilonidal anatomy, not HS. Establishes that the underlying technique is repeatable; HS outcomes must be measured separately.
- What it tested
- Long-term outcomes of pilonidal sinus laser-assisted closure with a 1470 nm intralesional radial-fiber technique.
- What it found
- Excellent long-term outcomes with low morbidity, supporting durability of the underlying technique.
- What it does not establish
- Pilonidal anatomy, not HS. Same caveat as the other SiLaC references — the device, fiber, and energy delivery transfer to HS; outcome rates do not.
Conceptual ancestor: deroofing
Deroofing is the conceptual ancestor of tissue-sparing tract management in HS — different device, same principle of preserving surrounding skin rather than excising it.
- What it tested
- Deroofing of HS sinus tracts and abscesses (88 patients, 414 lesions) with long-term follow-up.
- What it found
- Recurrence at the deroofed lesion was 17% at a mean follow-up of 34 months; high patient satisfaction.
- What it does not establish
- Deroofing is the conceptual ancestor of tissue-sparing tract closure. Establishes durability of the principle even though the device and approach differ from the 1470 nm intralesional technique.
Mechanism
The disease model
Why follicle therapy is rational rather than empirical. HS begins at the hair follicle — not the apocrine gland — and the downstream inflammation and tract formation flow from that initiating event.
- What it tested
- Histopathology of early HS lesions to characterize where inflammation begins.
- What it found
- Earliest inflammatory changes localize to the terminal hair follicle and immediately adjacent epidermis.
- What it does not establish
- Establishes the follicular origin of HS — the mechanistic basis for follicle-directed therapy being rational rather than empirical.
- What it tested
- Histopathologic review arguing HS originates in the hair follicle, not in apocrine glands.
- What it found
- The apocrine-gland model is historically incorrect; the disease is follicular in origin.
- What it does not establish
- Naming polemic, but the underlying point — that HS is a follicular, not glandular, disease — is now widely accepted and frames why follicle therapy makes sense.
- What it tested
- Comprehensive contemporary review of HS pathophysiology, epidemiology, comorbidities, and management.
- What it found
- Reinforces the follicular-origin disease model and frames HS as a systemic inflammatory disease requiring multimodal care.
- What it does not establish
- Review article, not a primary trial. Cited as the current comprehensive reference for the disease model that frames our procedural rationale.
The honest limits
Where the evidence is still thin
- There are no large head-to-head randomized trials comparing 1064 nm follicle-directed laser, 1470 nm intralesional sinus tract closure, deroofing, and wide excision in the same patient population. Choice of procedure is driven by Hurley stage, anatomy, and clinical judgment — not by a comparative trial that resolves the question definitively.
- Outcome measures in HS studies are heterogeneous. HiSCR, Sartorius score, IHS4, and modified HSSI are not interchangeable, and effect sizes are not directly comparable across studies that use different scales.
- Long-term registry data on laser approaches at five and ten years is sparse. We follow patients clinically and document outcomes; the field still needs more multicenter long-term data.
- The literature underrepresents anatomic subgroups. Perianal and gluteal disease are studied less than axillary disease, even though they carry the highest recovery burden.
- Patient-reported outcomes — pain, function, quality of life — are improving in HS research but remain underweighted relative to lesion counts. We weight them at consult regardless of what the literature emphasizes.
The framework we work within
Clinical guidelines
The North American and European guidelines frame HS as a multimodal disease requiring staged medical and procedural care. Our program is built inside this framework, not adjacent to it.
- What it tested
- Consensus methodology synthesizing the available evidence on diagnosis, evaluation, and procedural management of HS.
- What it found
- Procedural framework — including laser approaches and surgical options — that this program operates within.
- What it does not establish
- Guideline, not a trial. Part I covers the procedural side this site references; Part II (below) covers medical therapy.
- What it tested
- Consensus on topical, intralesional, and systemic medical management of HS, including biologics.
- What it found
- Framework for the medical-therapy half of multimodal HS care — biologics, antibiotics, and adjunctive medical management that pair with procedural intervention.
- What it does not establish
- Companion to Part I. Cited to make the multimodal posture explicit: procedural laser care sits inside a medical-therapy framework, not adjacent to one.
- What it tested
- European consensus guideline on HS classification and stepwise treatment.
- What it found
- Recommends staged, multimodal care; explicitly includes laser and surgical approaches alongside medical therapy.
- What it does not establish
- S1-level (consensus, not systematic review). Complements the North American guideline.
Review
When this page changes
This page is reviewed periodically and whenever a clinically meaningful new study lands. The current version was reviewed on .
If you are a clinician with a reference you think we should add or replace, please write us. We take the suggestion seriously.