Welcome to this April twenty twenty-six installment of our Dermatologic Surgery journal review. Four pieces on the table today — a homegrown intraoperative device, a ten-year single-institution look at atypical fibroxanthoma, a brief commentary on tattoo-machine peel delivery, and a systematic review of how we actually measure function around the mouth. Let's get into it.

First up is a technique article — a "how we do it" piece describing a novel device for intraoperative measurement of incisional tension. You know the underlying problem intimately: tension drives hypertrophic scarring, and yet despite decades of research into suture technique and postoperative tension-offloading, nobody has had a simple, sterilizable, one-handed way to actually quantify tension on the table. Prior tensiometer prototypes existed in the biomechanics literature, but they were wired, cable-laden lab instruments — nothing you'd bring into a surgical field.

The authors' solution borrows from an industrial part: a lateral force gauge normally used to measure force on switches and valves. They adapted it by giving it two parallel hook-tipped probes instead of one, since skin tension is bidirectional — the wound edges pull apart, they don't push against a single point like a switch would. One probe is fixed and thin and extends forward; both hooks pierce the dermis and grab either side of the incision. You zero the dial while holding the two probes overlapped and aligned with the wound edges reduced — that alignment step turned out to be the key to reproducibility during development — then you release the probes and let the wound tension pull them apart; the dial reads out the separation force directly, in grams-force.

They built the device in three spring scale ranges — 300, 500, and 2000 grams — to cover a range of incision tensions, validated the prototype first on pig skin, then sterilized it with ethylene oxide gas for human use. Reliability testing had three separate physicians measure the same twenty incisions, and agreement between them was essentially perfect — an intraclass correlation coefficient of point-nine-nine-nine, which for a hand-held clinical gauge is about as good as you're going to get.

The clinically interesting part is a worked case: a five-by-four centimeter elliptical nevus excision on the shoulder, where they pre-planned three possible closure directions based on skin laxity. Before undermining, their tension readings confirmed their prediction of which direction would be lowest-tension. But after just one centimeter of subcutaneous dissection, the tension values actually shifted enough that the optimal closure direction changed — which is a genuinely useful pearl: your pre-undermining tension assessment may not survive undermining, so if you're going to trust a direction, you may want to check it again after you've released the tissue. Across fifty cases — mixed nevus excisions and scar revisions, incision widths one-and-a-half to seven-and-a-half centimeters — measured tension ranged from fifty up to about three hundred ten grams-force, which the authors note roughly tracks with prior published closure-force data using very different methodology.

Practically, there's no control group, no scar-outcome endpoint, and no blinded correlation yet between measured tension and eventual scar quality — so calling this practice-changing today would be overreaching. What is worth banking is the concept and the accessibility: they quote a build cost under forty dollars, a two-minute measurement time, and ethylene oxide compatibility. If a commercial or reproducible open-source version becomes available, this could plausibly become a real intraoperative decision aid for closure direction on cosmetically or functionally high-stakes tension-prone sites. For now, file it as an interesting proof-of-concept worth watching, not something to adopt tomorrow.

Second is a retrospective cohort study, a single tertiary-center ten-year chart review of atypical fibroxanthoma and its more aggressive cousin, pleomorphic dermal sarcoma — sometimes still called undifferentiated pleomorphic sarcoma, terminology this institution's records straddled across the study period. The clinical gap they're addressing is a familiar one: AFX and PDS sit on a histologic spectrum that's genuinely hard to separate on a superficial shave biopsy, yet the distinction matters enormously for prognosis and follow-up intensity, and there's relatively little published data specifically on AFX-to-PDS transformation.

Methodologically, this is exactly the kind of question a retrospective design suits well — you're not testing an intervention, you're characterizing the natural history and outcomes of an uncommon tumor over a decade, and a retrospective review lets you accumulate a meaningfully large single-institution series that a prospective study realistically couldn't assemble in reasonable time. Cases were confirmed by dermatopathology, debulk specimens were vertically sectioned during Mohs to assess deeper invasion, and PDS was specifically ruled out histologically by absence of subcutaneous invasion, necrosis, lymphovascular invasion, or perineural invasion. Statistics were kept simple and appropriate — Fisher's exact test for categorical comparisons, Wilcoxon rank-sum for continuous variables — nothing fancier is needed for this kind of descriptive comparison.

The numbers land where you'd expect from prior literature but with a few notable specifics. A hundred eight patients, a hundred thirteen AFX tumors, five PDS cases, two of which were AFX tumors that transformed. Mean age at diagnosis was seventy-four, and the great majority were male. Roughly seven in ten patients had a history of some systemic malignancy, and about six in ten had a prior cutaneous malignancy — mostly basal cell and squamous cell carcinoma. Only two patients were immunosuppressed. The scalp was the single most common site at about four in ten tumors, with over eight in ten tumors located above the neck overall — consistent with prior series. Of the hundred eleven tumors treated with Mohs, clearance was achieved in one stage in a bit over four in ten cases and within two stages in the large majority — useful for setting patient expectations on stage count for this tumor type. Average preoperative tumor size was about three and a half square centimeters, and interestingly the average difference between pre- and postoperative defect size — about three and a quarter square centimeters — exceeded the two-centimeter margin previously reported as sufficient to clear AFX by Mohs, though the authors reasonably attribute this to their larger average starting tumor size compared with that older series rather than a true margin discrepancy.

The recurrence numbers are the clinically load-bearing figures here: four of a hundred eight patients recurred, a recurrence rate of about three and a half percent, slightly better than the roughly seven percent historically quoted — plausibly a Mohs effect. Median time to recurrence was about sixteen and a half months, a bit longer than prior reports, which the authors speculate may reflect delayed presentation in their largely rural referral population. Age over seventy-four and male sex — both present in three of their four recurrent patients — echo previously identified risk factors. The standout clinical teaching point is the fourth patient: an immunosuppressed lung transplant recipient who, despite clear Mohs margins, had three multifocal local recurrences and ultimately transformed to PDS with metastasis. That's a direct, actionable signal that immunosuppression deserves heightened suspicion and closer surveillance even after histologically clear margins — clear margins do not fully neutralize risk in this subgroup. Half of their recurrent tumors transformed to PDS, in both an immunocompetent and an immunosuppressed patient, reinforcing that transformation isn't exclusively an immunosuppression phenomenon, though it may be more aggressive when it occurs in that setting.

Limitations are the expected ones for this design: single-center, retrospective, relatively small recurrence numbers driving wide uncertainty around any subgroup comparisons, and terminology drift between AFX, PDS, and UPS across the ten-year record that required some retrospective reclassification.

The practical takeaway for your own practice is incremental but real: this reinforces standard vigilant follow-up for AFX after Mohs, and it specifically flags that immunosuppressed patients with AFX warrant a lower threshold for closer, longer surveillance and a higher index of suspicion for transformation to PDS even when margins are clear — that's the one piece of this paper worth actively incorporating rather than just filing as confirmatory epidemiology.

Third, briefly, is a commentary — a short expert reaction piece, not a study — responding to a separate paper characterizing dermal tattoo-machine delivery versus conventional topical application of croton oil and Hetter's phenol-croton oil formula for chemical peels. The commentator, writing from Emory, calls the underlying paper thoughtful and thorough, praising its histologic characterization of this emerging technique — essentially micro-needling or tattoo-machine delivery of wounding peel agents. He frames it explicitly as potentially a pilot for future work exploring different Hetter or trichloroacetic acid concentrations delivered by this route. There's no independent data here and no new methodology to unpack — it's simply a colleague's endorsement and a nod toward where this line of peel-delivery research might go next. Nothing actionable to extract beyond awareness that mechanized delivery of peel agents is an area to watch.

Last is a systematic review examining functional outcome measures used across perioral surgery — oncologic, reconstructive, and cosmetic. The gap being addressed is straightforward: the perioral region does a lot of mechanical work — speech, oral continence, eating, expression — and while we have plenty of outcome instruments across these three surgical domains, nobody had systematically asked how well those instruments actually capture function, as opposed to just aesthetics or generic quality of life.

Methodologically this is a rigorous, PRISMA-guided, PROSPERO-registered search across four databases spanning over fifty years of literature, with independent dual screening and a third-reviewer tiebreaker — interrater agreement was strong pre-reconciliation and reached perfect agreement after reconciliation, which tells you the categorization scheme was workable and reproducible. Importantly, they applied real psychometric inclusion thresholds — instruments had to show expert-confirmed content validity, statistically tested construct validity, and adequate interobserver or internal-consistency reliability — so this isn't just a list of every scale ever published, it's a curated set of tools that actually met validation standards.

Out of nearly eleven thousand initial records, they landed on a hundred one validated tools total: seventeen oncologic, twenty-nine reconstructive, fifty-five cosmetic. The headline finding is a stark asymmetry — function was assessed in ten of the seventeen oncologic tools and twelve of twenty-nine reconstructive tools, but in only two of fifty-five cosmetic tools. Speaking and eating dominated in oncologic instruments; speaking and smiling dominated in reconstructive ones. The two cosmetic tools that did touch function — the Face-Q Adverse Effects: Lips scale and the Face-Q Early Life Impact scale — covered function narrowly, and notably the Lips scale lumped laughing and smiling together under a single vague "lip movement" item rather than assessing them as the discrete, separately-scored functions that oncologic and reconstructive tools treat them as. The great majority of cosmetic tools — forty-one of fifty-five — assessed aesthetics exclusively, with over half of those measuring just a single feature like wrinkle severity or volume.

The discussion connects this to a real and growing clinical exposure: perioral cosmetic treatments targeting static wrinkles and volume loss can inadvertently impair dynamic facial movement, and that risk is magnified by the sheer volume of minimally invasive perioral cosmetic procedures now being performed — yet the tools we use to evaluate outcomes in that space are almost blind to function. They also note that even the better-performing tools, like the Facial Clinimetric Evaluation Scale in reconstructive surgery or the Face-Q Head and Neck Scale in oncology, weren't purpose-built for the perioral region specifically — they're borrowed from broader facial reanimation or head-and-neck contexts.

The authors are appropriately modest about limitations, flagging that their bibliometric classification approach, while grounded in established psychometric standards, still carries some subjectivity in how outcomes were bucketed into functional versus aesthetic versus quality-of-life categories.

For your practice, this is squarely in the "interesting, not yet actionable" category in terms of a specific instrument to adopt — there's no single validated perioral-specific functional scale yet to hand your patients. But it is a useful conceptual flag, especially for anyone doing cosmetic perioral work — fillers, neuromodulators, lip procedures — where the literature's own outcome tools are essentially not measuring whether you've preserved or impaired lip movement, speech, or expression. It's a reasonable prompt to at least informally assess function, not just aesthetic result, in your own perioral cosmetic follow-up until better-validated tools catch up.

That wraps our four articles for this April issue — a promising but early-stage tension-measuring gauge, a solid decade-long AFX series with a real message about immunosuppressed surveillance, a brief supportive commentary on tattoo-machine peel delivery, and a systematic review exposing a real blind spot in how we measure perioral cosmetic outcomes. Thanks for listening, and we'll see you next month.